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Plasma carotenoids, tocopherols, and retinol in the age-stratified (35–74 years) general population
(2016)
Blood micronutrient status may change with age. We analyzed plasma carotenoids, α-/γ-tocopherol, and retinol and their associations with age, demographic characteristics, and dietary habits (assessed by a short food frequency questionnaire) in a cross-sectional study of 2118 women and men (age-stratified from 35 to 74 years) of the general population from six European countries. Higher age was associated with lower lycopene and α-/β-carotene and higher β-cryptoxanthin, lutein, zeaxanthin, α-/γ-tocopherol, and retinol levels. Significant correlations with age were observed for lycopene (r = −0.248), α-tocopherol (r = 0.208), α-carotene (r = −0.112), and β-cryptoxanthin (r = 0.125; all p < 0.001). Age was inversely associated with lycopene (−6.5% per five-year age increase) and this association remained in the multiple regression model with the significant predictors (covariables) being country, season, cholesterol, gender, smoking status, body mass index (BMI (kg/m2)), and dietary habits. The positive association of α-tocopherol with age remained when all covariates including cholesterol and use of vitamin supplements were included (1.7% vs. 2.4% per five-year age increase). The association of higher β-cryptoxanthin with higher age was no longer statistically significant after adjustment for fruit consumption, whereas the inverse association of α-carotene with age remained in the fully adjusted multivariable model (−4.8% vs. −3.8% per five-year age increase). We conclude from our study that age is an independent predictor of plasma lycopene, α-tocopherol, and α-carotene.
Gut bacteria exert beneficial and harmful effects in metabolic diseases as deduced from the comparison of germfree and conventional mice and from fecal transplantation studies. Compositional microbial changes in diseased subjects have been linked to adiposity, type 2 diabetes and dyslipidemia. Promotion of an increased expression of intestinal nutrient transporters or a modified lipid and bile acid metabolism by the intestinal microbiota could result in an increased nutrient absorption by the host. The degradation of dietary fiber and the subsequent fermentation of monosaccharides to short-chain fatty acids (SCFA) is one of the most controversially discussed mechanisms of how gut bacteria impact host physiology. Fibers reduce the energy density of the diet, and the resulting SCFA promote intestinal gluconeogenesis, incretin formation and subsequently satiety. However, SCFA also deliver energy to the host and support liponeogenesis. Thus far, there is little knowledge on bacterial species that promote or prevent metabolic disease. Clostridium ramosum and Enterococcus cloacae were demonstrated to promote obesity in gnotobiotic mouse models, whereas bifidobacteria and Akkermansia muciniphila were associated with favorable phenotypes in conventional mice, especially when oligofructose was fed. How diet modulates the gut microbiota towards a beneficial or harmful composition needs further research. Gnotobiotic animals are a valuable tool to elucidate mechanisms underlying diet-host-microbe interactions.
Subsurface microbial communities undertake many terminal electron-accepting processes, often simultaneously. Using a tritium-based assay, we measured the potential hydrogen oxidation catalyzed by hydrogenase enzymes in several subsurface sedimentary environments (Lake Van, Barents Sea, Equatorial Pacific, and Gulf of Mexico) with different predominant electron-acceptors. Hydrogenases constitute a diverse family of enzymes expressed by microorganisms that utilize molecular hydrogen as a metabolic substrate, product, or intermediate. The assay reveals the potential for utilizing molecular hydrogen and allows qualitative detection of microbial activity irrespective of the predominant electron-accepting process. Because the method only requires samples frozen immediately after recovery, the assay can be used for identifying microbial activity in subsurface ecosystems without the need to preserve live material. We measured potential hydrogen oxidation rates in all samples from multiple depths at several sites that collectively span a wide range of environmental conditions and biogeochemical zones. Potential activity normalized to total cell abundance ranges over five orders of magnitude and varies, dependent upon the predominant terminal electron acceptor. Lowest per-cell potential rates characterize the zone of nitrate reduction and highest per-cell potential rates occur in the methanogenic zone. Possible reasons for this relationship to predominant electron acceptor include (i) increasing importance of fermentation in successively deeper biogeochemical zones and (ii) adaptation of H(2)ases to successively higher concentrations of H-2 in successively deeper zones.
In the study of relativistic jets one of the key open questions is their interaction with the environment on the microscopic level. Here, we study the initial evolution of both electron-proton (e(-)-p(+)) and electron-positron (e(+/-)) relativistic jets containing helical magnetic fields, focusing on their interaction with an ambient plasma. We have performed simulations of "global" jets containing helical magnetic fields in order to examine how helical magnetic fields affect kinetic instabilities such as the Weibel instability, the kinetic Kelvin-Helmholtz instability (kKHI) and the Mushroom instability (MI). In our initial simulation study these kinetic instabilities are suppressed and new types of instabilities can grow. In the e(-)-p(+) jet simulation a recollimation-like instability occurs and jet electrons are strongly perturbed. In the e(+/-) jet simulation a recollimation-like instability occurs at early times followed by a kinetic instability and the general structure is similar to a simulation without helical magnetic field. Simulations using much larger systems are required in order to thoroughly follow the evolution of global jets containing helical magnetic fields.
Decreasing groundwater levels in many parts of Germany and decreasing low flows in Central Europe have created a need for adaptation measures to stabilize the water balance and to increase low flows. The objective of our study was to estimate the impact of ditch water level management on stream-aquifer interactions in small lowland catchments of the mid-latitudes. The water balance of a ditch-irrigated area and fluxes between the subsurface and the adjacent stream were modeled for three runoff recession periods using the Hydrus-2D software package. The results showed that the subsurface flow to the stream was closely related to the difference between the water level in the ditch system and the stream. Evapotranspiration during the growing season additionally reduced base flow. It was crucial to stop irrigation during a recession period to decrease water withdrawal from the stream and enhance the base flow by draining the irrigated area. Mean fluxes to the stream were between 0.04 and 0.64 ls(-1) for the first 20 days of the low-flow periods. This only slightly increased the flow in the stream, whose mean was 57 ls(-1) during the period with the lowest flows. Larger areas would be necessary to effectively increase flows in mesoscale catchments.
Die vorliegende Arbeit beschäftigt sich mit dem Einfluss der Organisationsform von Mikrofinanzinstitutionen (MFIs) auf deren soziale Performance. In diesem Kontext wird die soziale Performance als die direkte Übersetzung der sozialen Mission der MFIs in die Praxis verstanden. Konkret wird die soziale Performance der zwei Organisationsformen Shareholder Owned Firm (SOF) sowie Non-Governmental Organisation (NGO) betrachtet und verglichen. Dieser Vergleich stützt sich auf die in der Fachwelt häufig vertretene Annahme, dass NGO MFIs eine höhere soziale Performance aufweisen als SOF MFIs, da sie dem Nonprofit-Sektor zugeschrieben werden können. Die bis dato vorhandenen relevanten empirischen Forschungen zu dem Thema werden anhand einer Literaturdiskussion analysiert. Bislang existiert nur eine relativ geringe Anzahl an empirischen Forschungen in diesem Themenfeld, da die Erforschung der sozialen Performance von MFIs ein recht neues Forschungsgebiet darstellt. Die Ergebnisse der Literaturdiskussion verdeutlichen zudem, dass hinsichtlich des Einflusses der Organisationsform von MFIs auf deren soziale Performance keine eindeutige Aussage getroffen werden kann, da die betrachteten Studien zu unterschiedlichen Resultaten kommen. Die Ergebnisse deuten jedoch darauf hin, dass in einigen geografischen Regionen der Welt NGO MFIs eine bessere soziale Performance aufweisen als SOF MFIs. Insgesamt liefert die Arbeit einen wichtigen Überblick über den Forschungsstand auf diesem Forschungsgebiet und deckt diverse Forschungslücken auf, welche in zukünftigen Untersuchungen berücksichtigt werden sollten.
Venomous snakes often display extensive variation in venom composition both between and within species. However, the mechanisms underlying the distribution of different toxins and venom types among populations and taxa remain insufficiently known. Rattlesnakes (Crotalus, Sistrurus) display extreme inter-and intraspecific variation in venom composition, centered particularly on the presence or absence of presynaptically neurotoxic phospholipases A2 such as Mojave toxin (MTX). Interspecific hybridization has been invoked as a mechanism to explain the distribution of these toxins across rattlesnakes, with the implicit assumption that they are adaptively advantageous. Here, we test the potential of adaptive hybridization as a mechanism for venom evolution by assessing the distribution of genes encoding the acidic and basic subunits of Mojave toxin across a hybrid zone between MTX-positive Crotalus scutulatus and MTX-negative C. viridis in southwestern New Mexico, USA. Analyses of morphology, mitochondrial and single copy-nuclear genes document extensive admixture within a narrow hybrid zone. The genes encoding the two MTX subunits are strictly linked, and found in most hybrids and backcrossed individuals, but not in C. viridis away from the hybrid zone. Presence of the genes is invariably associated with presence of the corresponding toxin in the venom. We conclude that introgression of highly lethal neurotoxins through hybridization is not necessarily favored by natural selection in rattlesnakes, and that even extensive hybridization may not lead to introgression of these genes into another species.
Effects of data and model simplification on the results of a wetland water resource management model
(2016)
This paper presents the development of a wetland water balance model for use in a large river basin with many different wetlands. The basic model was primarily developed for a single wetland with a complex water management system involving large amounts of specialized input data and water management details. The aim was to simplify the model structure and to use only commonly available data as input for the model, with the least possible loss of accuracy. Results from different variants of the model and data adaptation were tested against results from a detailed model. This shows that using commonly available data and unifying and simplifying the input data is tolerable up to a certain level. The simplification of the model has greater effects on the evaluated water balance components than the data adaptation. Because this simplification was necessary for large-scale use, we suggest that, for reasons of comparability, simpler models should always be applied with uniform data bases for large regions, though these should only be moderately simplified. Further, we recommend using these simplified models only for large-scale comparisons and using more specific, detailed models for investigations on smaller scales.
Background:
Skewed body size distributions and the high relative richness of small-bodied taxa are a fundamental
property of a wide range of animal clades. The evolutionary processes responsible for generating these distributions
are well described in vertebrate model systems but have yet to be explored in detail for other major terrestrial
clades. In this study, we explore the macro-evolutionary patterns of body size variation across families of Hexapoda
(insects and their close relatives), using recent advances in phylogenetic understanding, with an aim to investigate
the link between size and diversity within this ancient and highly diverse lineage.
Results:
The maximum, minimum and mean-log body lengths of hexapod families are all approximately log-normally
distributed, consistent with previous studies at lower taxonomic levels, and contrasting with skewed distributions
typical of vertebrate groups. After taking phylogeny and within-tip variation into account, we find no evidence for a
negative relationship between diversification rate and body size, suggesting decoupling of the forces controlling these
two traits. Likelihood-based modeling of the log-mean body size identifies distinct processes operating within
Holometabola and Diptera compared with other hexapod groups, consistent with accelerating rates of size evolution
within these clades, while as a whole, hexapod body size evolution is found to be dominated by neutral processes
including significant phylogenetic conservatism.
Conclusions:
Based on our findings we suggest that the use of models derived from well-studied but atypical clades,
such as vertebrates may lead to misleading conclusions when applied to other major terrestrial lineages. Our results
indicate that within hexapods, and within the limits of current systematic and phylogenetic knowledge, insect
diversification is generally unfettered by size-biased macro-evolutionary processes, and that these processes over large
timescales tend to converge on apparently neutral evolutionary processes. We also identify limitations on available
data within the clade and modeling approaches for the resolution of trees of higher taxa, the resolution of which may
collectively enhance our understanding of this key component of terrestrial ecosystems.
Lake Towuti is a tectonic basin, surrounded by ultramafic rocks. Lateritic soils form through weathering and deliver abundant iron (oxy)hydroxides but very little sulfate to the lake and its sediment. To characterize the sediment biogeochemistry, we collected cores at three sites with increasing water depth and decreasing bottom water oxygen concentrations. Microbial cell densities were highest at the shallow site a feature we attribute to the availability of labile organic matter (OM) and the higher abundance of electron acceptors due to oxic bottom water conditions. At the two other sites, OM degradation and reduction processes below the oxycline led to partial electron acceptor depletion. Genetic information preserved in the sediment as extracellular DNA (eDNA) provided information on aerobic and anaerobic heterotrophs related to Nitrospirae. Chloroflexi, and Therrnoplasmatales. These taxa apparently played a significant role in the degradation of sinking OM. However, eDNA concentrations rapidly decreased with core depth. Despite very low sulfate concentrations, sulfate-reducing bacteria were present and viable in sediments at all three sites, as confirmed by measurement of potential sulfate reduction rates. Microbial community fingerprinting supported the presence of taxa related to Deltaproteobacteria and Firmicutes with demonstrated capacity for iron and sulfate reduction. Concomitantly, sequences of Ruminococcaceae, Clostridiales, and Methanornicrobiales indicated potential for fermentative hydrogen and methane production. Such first insights into ferruginous sediments showed that microbial populations perform successive metabolisms related to sulfur, iron, and methane. In theory, iron reduction could reoxidize reduced sulfur compounds and desorb OM from iron minerals to allow remineralization to methane. Overall, we found that biogeochemical processes in the sediments can be linked to redox differences in the bottom waters of the three sites, like oxidant concentrations and the supply of labile OM. At the scale of the lacustrine record, our geomicrobiological study should provide a means to link the extant subsurface biosphere to past environments.
Background:
Deception can distort psychological tests on socially sensitive topics. Understanding the cerebral
processes that are involved in such faking can be useful in detection and prevention of deception. Previous research
shows that faking a brief implicit association test (BIAT ) evokes a characteristic ERP response. It is not yet known
whether temporarily available self-control resources moderate this response. We randomly assigned 22 participants
(15 females, 24.23
±
2.91
years old) to a counterbalanced repeated-measurements design. Participants first com-
pleted a Brief-IAT (BIAT ) on doping attitudes as a baseline measure and were then instructed to fake a negative dop
-
ing attitude both when self-control resources were depleted and non-depleted. Cerebral activity during BIAT perfor
-
mance was assessed using high-density EEG.
Results:
Compared to the baseline BIAT, event-related potentials showed a first interaction at the parietal P1,
while significant post hoc differences were found only at the later occurring late positive potential. Here, signifi-
cantly decreased amplitudes were recorded for ‘normal’ faking, but not in the depletion condition. In source space,
enhanced activity was found for ‘normal’ faking in the bilateral temporoparietal junction. Behaviorally, participants
were successful in faking the BIAT successfully in both conditions.
Conclusions:
Results indicate that temporarily available self-control resources do not affect overt faking success on
a BIAT. However, differences were found on an electrophysiological level. This indicates that while on a phenotypical
level self-control resources play a negligible role in deliberate test faking the underlying cerebral processes are markedly different.
Background:
Arising from the relevance of sensorimotor training in the therapy of nonspecific low back pain patients and from the value of individualized therapy, the present trial aims to test the feasibility and efficacy of individualized sensorimotor training interventions in patients suffering from nonspecific low back pain.
Methods and study design:
A multicentre, single-blind two-armed randomized controlled trial to evaluate the
effects of a 12-week (3 weeks supervised centre-based and 9 weeks home-based) individualized sensorimotor exercise program is performed. The control group stays inactive during this period. Outcomes are pain, and pain-associated function as well as motor function in adults with nonspecific low back pain. Each participant is scheduled to five measurement dates: baseline (M1), following centre-based training (M2), following home-based training (M3) and at two follow-up time points 6 months (M4) and 12 months (M5) after M1. All investigations and the assessment of the primary and secondary outcomes are performed in a standardized order: questionnaires – clinical examination – biomechanics (motor function). Subsequent statistical procedures are executed after the examination of underlying assumptions for parametric or rather non-parametric testing.
Discussion:
The results and practical relevance of the study will be of clinical and practical relevance not only for researchers and policy makers but also for the general population suffering from nonspecific low back pain.
Trial registration:
Identification number DRKS00010129. German Clinical Trial registered on 3 March 2016.
Background:
All living cells display a rapid molecular response to adverse environmental conditions, and
the heat shock protein family reflects one such example. Hence, failing to activate heat shock proteins can impair
the cellular response. In the present study, we evaluated whether the loss of different isoforms of heat shock
protein (
hsp
) genes in
Caenorhabditis elegans
would affect their vulnerability to Manganese (Mn) toxicity.
Methods:
We exposed wild type and selected
hsp
mutant worms to Mn (30 min) and next evaluated
further the most susceptible strains. We analyzed survi
val, protein carbonylation (as a marker of oxidative
stress) and Parkinson
’
s disease related gene expression immediately after Mn exposure. Lastly, we observed
dopaminergic neurons in wild type worms and in
hsp-70
mutants following Mn treatment. Analysis of the
data was performed by one-way or two way ANOVA, depending on the case, followed by post-hoc
Bonferroni test if the overall
p
value was less than 0.05.
Results:
We verified that the loss of
hsp-70, hsp-3 and chn-1
increased the vulnerability to Mn, as
exposed mutant worms showed lower survival rate and increased protein oxidation. The importance of
hsp-70
against Mn toxicity was then corroborated in dopaminergic neurons, where Mn neurotoxicity was
aggravated. The lack of
hsp-70
also blocked the transcriptional upregulation of
pink1
, a gene that has been
linked to Parkinson
’
sdisease.
Conclusions:
Taken together, our data suggest that Mn exposu
re modulates heat shock protein expression,
particularly HSP-70, in
C. elegans
.Furthermore,lossof
hsp-70
increases protein oxidation and dopaminergic
neuronal degeneration following manganese exposure, which is associated with the inhibition of
pink1
increased expression, thus pot
entially exacerbating the v
ulnerability to this metal.
Background:
Environmental stress puts organisms at risk and requires specific stress-tailored responses to maximize
survival. Long-term exposure to stress necessitates a global reprogramming of the cellular activities at different
levels of gene expression.
Results:
Here, we use ribosome profiling and RNA sequencing to globally profile the adaptive response of
Arabidopsis thaliana
to prolonged heat stress. To adapt to long heat exposure, the expression of many genes is
modulated in a coordinated manner at a transcriptional and translational level. However, a significant group of
genes opposes this trend and shows mainly translational regulation. Different secondary structure elements are
likely candidates to play a role in regulating translation of those genes.
Conclusions:
Our data also uncover on how the subunit stoichiometry of multimeric protein complexes in plastids
is maintained upon heat exposure.
Background:
First metabolomics studies have indicated that metabolic fingerprints from accessible tissues might
be useful to better understand the etiological links between metabolism and cancer. However, there is still a lack
of prospective metabolomics studies on pre-diagnostic metabolic alterations and cancer risk.
Methods:
Associations between pre-diagnostic levels of 120 circulating metabolites (acylcarnitines, amino acids,
biogenic amines, phosphatidylcholines, sphingolipids, and hexoses) and the risks of breast, prostate, and colorectal
cancer were evaluated by Cox regression analyses using data of a prospective case-cohort study including 835
incident cancer cases.
Results:
The median follow-up duration was 8.3 years among non-cases and 6.5 years among incident cases of
cancer. Higher levels of lysophosphatidylcholines (lysoPCs), and especially lysoPC a C18:0, were consistently related
to lower risks of breast, prostate, and colorectal cancer, independent of background factors. In contrast, higher
levels of phosphatidylcholine PC ae C30:0 were associated with increased cancer risk. There was no heterogeneity
in the observed associations by lag time between blood draw and cancer diagnosis.
Conclusion:
Changes in blood lipid composition precede the diagnosis of common malignancies by several years.
Considering the consistency of the present results across three cancer types the observed alterations point to a
global metabolic shift in phosphatidylcholine metabolism that may drive tumorigenesis.
Aim: We aimed to identify patient characteristics and comorbidities that correlate with the initial exercise capacity of
cardiac rehabilitation (CR) patients and to study the significance of patient characteristics, comorbidities and training
methods for training achievements and final fitness of CR patients.
Methods: We studied 557 consecutive patients (51.7 Æ 6.9 years; 87.9% men) admitted to a three-week in-patient CR.
Cardiopulmonary exercise testing (CPX) was performed at discharge. Exercise capacity (watts) at entry, gain in training
volume and final physical fitness (assessed by peak O 2 utilization (VO 2peak ) were analysed using analysis of covariance
(ANCOVA) models.
Results: Mean training intensity was 90.7 Æ 9.7% of maximum heart rate (81% continuous/19% interval training, 64%
additional strength training). A total of 12.2 Æ 2.6 bicycle exercise training sessions were performed. Increase of training
volume by an average of more than 100% was achieved (difference end/beginning of CR: 784 Æ 623 watts  min). In the
multivariate model the gain in training volume was significantly associated with smoking, age and exercise capacity at
entry of CR. The physical fitness level achieved at discharge from CR as assessed by VO 2peak was mainly dependent on
age, but also on various factors related to training, namely exercise capacity at entry, increase of training volume and
training method.
Conclusion: CR patients were trained in line with current guidelines with moderate-to-high intensity and reached a
considerable increase of their training volume. The physical fitness level achieved at discharge from CR depended on
various factors associated with training, which supports the recommendation that CR should be offered to all cardiac
patients.
Editorial
(2016)
Background
Antiphospholipid antibodies (aPL) can be detected in asymptomatic carriers and infectious patients. The aim was to investigate whether a novel line immunoassay (LIA) differentiates between antiphospholipid syndrome (APS) and asymptomatic aPL+ carriers or patients with infectious diseases (infectious diseases controls (IDC)).
Methods
Sixty-one patients with APS (56 primary, 22/56 with obstetric events only, and 5 secondary), 146 controls including 24 aPL+ asymptomatic carriers and 73 IDC were tested on a novel hydrophobic solid phase coated with cardiolipin (CL), phosphatic acid, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylserine, beta2-glycoprotein I (β2GPI), prothrombin, and annexin V. Samples were also tested by anti-CL and anti-β2GPI ELISAs and for lupus anticoagulant activity. Human monoclonal antibodies (humoAbs) against human β2GPI or PL alone were tested on the same LIA substrates in the absence or presence of human serum, purified human β2GPI or after CL-micelle absorption.
Results
Comparison of LIA with the aPL-classification assays revealed good agreement for IgG/IgM aß2GPI and aCL. Anti-CL and anti-ß2GPI IgG/IgM reactivity assessed by LIA was significantly higher in patients with APS versus healthy controls and IDCs, as detected by ELISA. IgG binding to CL and ß2GPI in the LIA was significantly lower in aPL+ carriers and Venereal Disease Research Laboratory test (VDRL) + samples than in patients with APS. HumoAb against domain 1 recognized β2GPI bound to the LIA-matrix and in anionic phospholipid (PL) complexes. Absorption with CL micelles abolished the reactivity of a PL-specific humoAb but did not affect the binding of anti-β2GPI humoAbs.
Conclusions
The LIA and ELISA have good agreement in detecting aPL in APS, but the LIA differentiates patients with APS from infectious patients and asymptomatic carriers, likely through the exposure of domain 1.
A model analysis of mechanisms for radial microtubular patterns at root hair initiation sites
(2016)
Plant cells have two main modes of growth generating anisotropic structures. Diffuse growth where whole cell walls extend in specific directions, guided by anisotropically positioned cellulose fibers, and tip growth, with inhomogeneous addition of new cell wall material at the tip of the structure. Cells are known to regulate these processes via molecular signals and the cytoskeleton. Mechanical stress has been proposed to provide an input to the positioning of the cellulose fibers via cortical microtubules in diffuse growth. In particular, a stress feedback model predicts a circumferential pattern of fibers surrounding apical tissues and growing primordia, guided by the anisotropic curvature in such tissues. In contrast, during the initiation of tip growing root hairs, a star-like radial pattern has recently been observed. Here, we use detailed finite element models to analyze how a change in mechanical properties at the root hair initiation site can lead to star-like stress patterns in order to understand whether a stress-based feedback model can also explain the microtubule patterns seen during root hair initiation. We show that two independent mechanisms, individually or combined, can be sufficient to generate radial patterns. In the first, new material is added locally at the position of the root hair. In the second, increased tension in the initiation area provides a mechanism. Finally, we describe how a molecular model of Rho-of-plant (ROP) GTPases activation driven by auxin can position a patch of activated ROP protein basally along a 2D root epidermal cell plasma membrane, paving the way for models where mechanical and molecular mechanisms cooperate in the initial placement and outgrowth of root hairs.
Infants start learning the prosodic properties of their native language before 12 months, as shown by the emergence of a trochaic bias in English-learning infants between 6 and 9 months (Jusczyk et al., 1993), and in German-learning infants between 4 and 6 months (Huhle et al., 2009, 2014), while French-learning infants do not show a bias at 6 months (Hohle et al., 2009). This language-specific emergence of a trochaic bias is supported by the fact that English and German are languages with trochaic predominance in their lexicons, while French is a language with phrase-final lengthening but lacking lexical stress. We explored the emergence of a trochaic bias in bilingual French/German infants, to study whether the developmental trajectory would be similar to monolingual infants and whether amount of relative exposure to the two languages has an impact on the emergence of the bias. Accordingly, we replicated Hohle et al. (2009) with 24 bilingual 6-month-olds learning French and German simultaneously. All infants had been exposed to both languages for 30 to 70% of the time from birth. Using the Head Preference Procedure, infants were presented with two lists of stimuli, one made up of several occurrences of the pseudoword /GAba/ with word-initial stress (trochaic pattern), the second one made up of several occurrences of the pseudoword /gaBA/ with word-final stress (iambic pattern). The stimuli were recorded by a native German female speaker. Results revealed that these French/German bilingual 6-month olds have a trochaic bias (as evidenced by a preference to listen to the trochaic pattern). Hence, their listening preference is comparable to that of monolingual German-learning 6-month-olds, but differs from that of monolingual French-learning 6-month-olds who did not show any preference (Noble et al., 2009). Moreover, the size of the trochaic bias in the bilingual infants was not correlated with their amount of exposure to German. The present results thus establish that the development of a trochaic bias in simultaneous bilinguals is not delayed compared to monolingual German-learning infants (Hohle et al., 2009) and is rather independent of the amount of exposure to German relative to French.
Liverwort Blasia pusilla L. recruits soil nitrogen-fixing cyanobacteria of genus Nostoc as symbiotic partners. In this work we compared Nostoc community composition inside the plants and in the soil around them from two distant locations in Northern Norway. STRR fingerprinting and 16S rDNA phylogeny reconstruction showed a remarkable local diversity among isolates assigned to several Nostoc clades. An extensive web of negative allelopathic interactions was recorded at an agricultural site, but not at the undisturbed natural site. The cell extracts of the cyanobacteria did not show antimicrobial activities, but four isolates were shown to be cytotoxic to human cells. The secondary metabolite profiles of the isolates were mapped by MALDI-TOF MS, and the most prominent ions were further analyzed by Q-TOF for MS/MS aided identification. Symbiotic isolates produced a great variety of small peptide-like substances, most of which lack any record in the databases. Among identified compounds we found microcystin and nodularin variants toxic to eukaryotic cells. Microcystin producing chemotypes were dominating as symbiotic recruits but not in the free-living community. In addition, we were able to identify several novel aeruginosins and banyaside-like compounds, as well as nostocyclopeptides and nosperin.
Drugs as instruments
(2016)
Neuroenhancement (NE) is the non-medical use of psychoactive substances to produce a subjective enhancement in psychological functioning and experience. So far empirical investigations of individuals' motivation for NE however have been hampered by the lack of theoretical foundation. This study aimed to apply drug instrumentalization theory to user motivation for NE. We argue that NE should be defined and analyzed from a behavioral perspective rather than in terms of the characteristics of substances used for NE. In the empirical study we explored user behavior by analyzing relationships between drug options (use over-the-counter products, prescription drugs, illicit drugs) and postulated drug instrumentalization goals (e.g., improved cognitive performance, counteracting fatigue, improved social interaction). Questionnaire data from 1438 university students were subjected to exploratory and confirmatory factor analysis to address the question of whether analysis of drug instrumentalization should be based on the assumption that users are aiming to achieve a certain goal and choose their drug accordingly or whether NE behavior is more strongly rooted in a decision to try or use a certain drug option. We used factor mixture modeling to explore whether users could be separated into qualitatively different groups defined by a shared "goal X drug option" configuration. Our results indicate, first, that individuals decisions about NE are eventually based on personal attitude to drug options (e.g., willingness to use an over-the-counter product but not to abuse prescription drugs) rather than motivated by desire to achieve a specific goal (e.g., fighting tiredness) for which different drug options might be tried. Second, data analyses suggested two qualitatively different classes of users. Both predominantly used over-the-counter products, but "neuroenhancers" might be characterized by a higher propensity to instrumentalize over-the-counter products for virtually all investigated goals whereas "fatigue-fighters" might be inclined to use over-the-counter products exclusively to fight fatigue. We believe that psychological investigations like these are essential, especially for designing programs to prevent risky behavior.
Calcularis is a computer-based training program which focuses on basic numerical skills, spatial representation of numbers and arithmetic operations. The program includes a user model allowing flexible adaptation to the child's individual knowledge and learning profile. The study design to evaluate the training comprises three conditions (Calcularis group, waiting control group, spelling training group). One hundred and thirty-eight children from second to fifth grade participated in the study. Training duration comprised a minimum of 24 training sessions of 20 min within a time period of 6-8 weeks. Compared to the group without training (waiting control group) and the group with an alternative training (spelling training group), the children of the Calcularis group demonstrated a higher benefit in subtraction and number line estimation with medium to large effect sizes. Therefore, Calcularis can be used effectively to support children in arithmetic performance and spatial number representation.
Effects of resistance training in youth athletes on muscular fitness and athletic performance
(2016)
During the stages of long-term athlete development (LTAD), resistance training (RT) is an important means for (i) stimulating athletic development, (ii) tolerating the demands of long-term training and competition, and (iii) inducing long-term health promoting effects that are robust over time and track into adulthood. However, there is a gap in the literature with regards to optimal RT methods during LTAD and how RT is linked to biological age. Thus, the aims of this scoping review were (i) to describe and discuss the effects of RT on muscular fitness and athletic performance in youth athletes, (ii) to introduce a conceptual model on how to appropriately implement different types of RT within LTAD stages, and (iii) to identify research gaps from the existing literature by deducing implications for future research. In general, RT produced small -to -moderate effects on muscular fitness and athletic performance in youth athletes with muscular strength showing the largest improvement. Free weight, complex, and plyometric training appear to be well -suited to improve muscular fitness and athletic performance. In addition, balance training appears to be an important preparatory (facilitating) training program during all stages of LTAD but particularly during the early stages. As youth athletes become more mature, specificity, and intensity of RT methods increase. This scoping review identified research gaps that are summarized in the following and that should be addressed in future studies: (i) to elucidate the influence of gender and biological age on the adaptive potential following RT in youth athletes (especially in females), (ii) to describe RT protocols in more detail (i.e., always report stress and strain based parameters), and (iii) to examine neuromuscular and tendomuscular adaptations following RT in youth athletes.
Previous research on the interplay between static manual postures and visual attention revealed enhanced visual selection near the hands (near-hand effect). During active movements there is also superior visual performance when moving toward compared to away from the stimulus (direction effect). The "modulated visual pathways" hypothesis argues that differential involvement of magno- and parvocellular visual processing streams causes the near-hand effect. The key finding supporting this hypothesis is an increase in temporal and a reduction in spatial processing in near-hand space (Gozli et al., 2012). Since this hypothesis has, so far, only been tested with static hand postures, we provide a conceptual replication of Gozli et al.'s (2012) result with moving hands, thus also probing the generality of the direction effect. Participants performed temporal or spatial gap discriminations while their right hand was moving below the display. In contrast to Gozli et al (2012), temporal gap discrimination was superior at intermediate and not near hand proximity. In spatial gap discrimination, a direction effect without hand proximity effect suggests that pragmatic attentional maps overshadowed temporal/spatial processing biases for far/near-hand space.
An exploration of rhythmic grouping of speech sequences by french- and german-learning infants
(2016)
Rhythm in music and speech can be characterized by a constellation of several acoustic cues. Individually, these cues have different effects on rhythmic perception: sequences of sounds alternating in duration are perceived as short-long pairs (weak-strong/iambicpattern), whereas sequences of sounds alternating in intensity or pitch are perceived as loud-soft, or high-low pairs (strong-weak/trochaic pattern). This perceptual bias-called the lambic-Trochaic Law (ITL) has been claimed to be an universal property of the auditory system applying in both the music and the language domains. Recent studies have shown that language experience can modulate the effects of the ITL on rhythmic perception of both speech and non-speech sequences in adults, and of non-speech sequences in 7.5-month-old infants. The goal of the present study was to explore whether language experience also modulates infants' grouping of speech. To do so, we presented sequences of syllables to monolingual French- and German-learning 7.5-month-olds. Using the Headturn Preference Procedure (HPP), we examined whether they were able to perceive a rhythmic structure in sequences of syllables that alternated in duration, pitch, or intensity. Our findings show that both French- and German-learning infants perceived a rhythmic structure when it was cued by duration or pitch but not intensity. Our findings also show differences in how these infants use duration and pitch cues to group syllable sequences, suggesting that pitch cues were the easier ones to use. Moreover, performance did not differ across languages, failing to reveal early language effects on rhythmic perception. These results contribute to our understanding of the origin of rhythmic perception and perceptual mechanisms shared across music and speech, which may bootstrap language acquisition.
Relatedness strongly influences social behaviors in a wide variety of species. For most species, the highest typical degree of relatedness is between full siblings with 50% shared genes. However, this is poorly understood in species with unusually high relatedness between individuals: clonal organisms. Although there has been some investigation into clonal invertebrates and yeast, nothing is known about kin selection in clonal vertebrates. We show that a clonal fish, the Amazon molly (Poecilia formosa), can distinguish between different clonal lineages, associating with genetically identical, sister clones, and use multiple sensory modalities. Also, they scale their aggressive behaviors according to the relatedness to other females: they are more aggressive to non-related clones. Our results demonstrate that even in species with very small genetic differences between individuals, kin recognition can be adaptive. Their discriminatory abilities and regulation of costly behaviors provides a powerful example of natural selection in species with limited genetic diversity.
Background:
Exercising at intensities where fat oxidation rates are high has been shown to induce metabolic benefits in recreational and health-oriented sportsmen. The exercise intensity (Fat peak ) eliciting peak fat oxidation rates is therefore of particular interest when aiming to prescribe exercise for the purpose of fat oxidation and related metabolic effects. Although running and walking are feasible and popular among the target population, no reliable protocols are available to assess Fat peak as well as its actual velocity (V PFO ) during treadmill ergometry. Our purpose was therefore, to assess the reliability and day-to-day variability of V PFO and Fat peak during treadmill ergometry running.
Methods:
Sixteen recreational athletes (f = 7, m = 9; 25 ± 3 y; 1.76 ± 0.09 m; 68.3 ± 13.7 kg; 23.1 ± 2.9 kg/m 2 ) performed 2 different running protocols on 3 different days with standardized nutrition the day before testing. At day 1, peak oxygen uptake (VO 2peak ) and the velocities at the aerobic threshold (V LT ) and respiratory exchange ratio (RER) of 1.00 (V RER ) were assessed. At days 2 and 3, subjects ran an identical submaximal incremental test (Fat-peak test) composed of a 10 min warm-up (70 % V LT ) followed by 5 stages of 6 min with equal increments (stage 1 = V LT , stage 5 = V RER ). Breath-by-breath gas exchange data was measured continuously and used to determine fat oxidation rates. A third order polynomial function was used to identify V PFO and subsequently Fat peak . The reproducibility and variability of variables was verified with an int raclass correlation coef ficient (ICC), Pearson ’ s correlation coefficient, coefficient of variation (CV) an d the mean differences (bias) ± 95 % limits of agreement (LoA).
Results:
ICC, Pearson ’ s correlation and CV for V PFO and Fat peak were 0.98, 0.97, 5.0 %; and 0.90, 0.81, 7.0 %, respectively. Bias ± 95 % LoA was − 0.3 ± 0.9 km/h for V PFO and − 2±8%ofVO 2peak for Fat peak.
Conclusion:
In summary, relative and absolute reliability indicators for V PFO and Fat peak were found to be excellent. The observed LoA may now serve as a basis for future training prescriptions, although fat oxidation rates at prolonged exercise bouts at this intensity still need to be investigated.
Background The prognostic effect of multi-component cardiac rehabilitation (CR) in the modern era of statins and acute revascularisation remains controversial. Focusing on actual clinical practice, the aim was to evaluate the effect of CR on total mortality and other clinical endpoints after an acute coronary event.
Design Structured review and meta-analysis.
Methods Randomised controlled trials (RCTs), retrospective controlled cohort studies (rCCSs) and prospective controlled cohort studies (pCCSs) evaluating patients after acute coronary syndrome (ACS), coronary artery bypass grafting (CABG) or mixed populations with coronary artery disease (CAD) were included, provided the index event was in 1995 or later.
Results Out of n=18,534 abstracts, 25 studies were identified for final evaluation (RCT: n=1; pCCS: n=7; rCCS: n=17), including n=219,702 patients (after ACS: n=46,338; after CABG: n=14,583; mixed populations: n=158,781; mean follow-up: 40 months). Heterogeneity in design, biometrical assessment of results and potential confounders was evident. CCSs evaluating ACS patients showed a significantly reduced mortality for CR participants (pCCS: hazard ratio (HR) 0.37, 95% confidence interval (CI) 0.20-0.69; rCCS: HR 0.64, 95% CI 0.49-0.84; odds ratio 0.20, 95% CI 0.08-0.48), but the single RCT fulfilling Cardiac Rehabilitation Outcome Study (CROS) inclusion criteria showed neutral results. CR participation was also associated with reduced mortality after CABG (rCCS: HR 0.62, 95% CI 0.54-0.70) and in mixed CAD populations.
Conclusions CR participation after ACS and CABG is associated with reduced mortality even in the modern era of CAD treatment. However, the heterogeneity of study designs and CR programmes highlights the need for defining internationally accepted standards in CR delivery and scientific evaluation.
SOPARSE predicts so-called local coherence effects: locally plausible but globally impossible parses of substrings can exert a distracting influence during sentence processing. Additionally, it predicts digging-in effects: the longer the parser stays committed to a particular analysis, the harder it becomes to inhibit that analysis. We investigated the interaction of these two predictions using German sentences. Results from a self-paced reading study show that the processing difficulty caused by a local coherence can be reduced by first allowing the globally correct parse to become entrenched, which supports SOPARSE’s assumptions.
Consonants have been proposed to carry more of the weight of lexical processing than vowels. This consonant bias has consistently been found in adults and has been proposed to facilitate early language acquisition. We explore the origins of this bias over the course of development and in infants learning different languages. Although the consonant bias was originally thought to be present at birth, evidence suggests that it arises from the early stages of phonological and (pre-)lexical acquisition. We discuss two theories that account for the acquisition of the consonant bias: the lexical and acoustic-phonetic hypotheses.
Skipping a grade, one specific form of acceleration, is an intervention used for gifted students. Quantitative research has shown acceleration to be a highly successful intervention regarding academic achievement, but less is known about the social-emotional outcomes of grade-skipping. In the present study, the authors used the grounded theory approach to examine the experiences of seven gifted students aged 8 to 16 years who skipped a grade. The interviewees perceived their feeling of being in the wrong place before the grade-skipping as strongly influenced by their teachers, who generally did not respond adequately to their needs. We observed a close interrelationship between the gifted students' intellectual fit and their social situation in class. Findings showed that the grade-skipping in most of the cases bettered the situation in school intellectually as well as socially, but soon further interventions, for instance, a specialized and demanding class- or subject-specific acceleration were added to provide sufficiently challenging learning opportunities.
Robust appraisals of climate impacts at different levels of global-mean temperature increase are vital to guide assessments of dangerous anthropogenic interference with the climate system. The 2015 Paris Agreement includes a two-headed temperature goal: "holding the increase in the global average temperature to well below 2 degrees C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 degrees C". Despite the prominence of these two temperature limits, a comprehensive overview of the differences in climate impacts at these levels is still missing. Here we provide an assessment of key impacts of climate change at warming levels of 1.5 degrees C and 2 degrees C, including extreme weather events, water availability, agricultural yields, sea-level rise and risk of coral reef loss. Our results reveal substantial differences in impacts between a 1.5 degrees C and 2 degrees C warming that are highly relevant for the assessment of dangerous anthropogenic interference with the climate system. For heat-related extremes, the additional 0.5 degrees C increase in global-mean temperature marks the difference between events at the upper limit of present-day natural variability and a new climate regime, particularly in tropical regions. Similarly, this warming difference is likely to be decisive for the future of tropical coral reefs. In a scenario with an end-of-century warming of 2 degrees C, virtually all tropical coral reefs are projected to be at risk of severe degradation due to temperature-induced bleaching from 2050 onwards. This fraction is reduced to about 90% in 2050 and projected to decline to 70% by 2100 for a 1.5 degrees C scenario. Analyses of precipitation-related impacts reveal distinct regional differences and hot-spots of change emerge. Regional reduction in median water availability for the Mediterranean is found to nearly double from 9% to 17% between 1.5 degrees C and 2 degrees C, and the projected lengthening of regional dry spells increases from 7 to 11%. Projections for agricultural yields differ between crop types as well as world regions. While some (in particular high-latitude) regions may benefit, tropical regions like West Africa, South-East Asia, as well as Central and northern South America are projected to face substantial local yield reductions, particularly for wheat and maize. Best estimate sea-level rise projections based on two illustrative scenarios indicate a 50cm rise by 2100 relative to year 2000-levels for a 2 degrees C scenario, and about 10 cm lower levels for a 1.5 degrees C scenario. In a 1.5 degrees C scenario, the rate of sea-level rise in 2100 would be reduced by about 30% compared to a 2 degrees C scenario. Our findings highlight the importance of regional differentiation to assess both future climate risks and different vulnerabilities to incremental increases in global-mean temperature. The article provides a consistent and comprehensive assessment of existing projections and a good basis for future work on refining our understanding of the difference between impacts at 1.5 degrees C and 2 degrees C warming.
Studies investigating the effect of increasing CO2 levels on the phosphorus cycle in natural waters are lacking although phosphorus often controls phytoplankton development in many aquatic systems. The aim of our study was to analyse effects of elevated CO2 levels on phosphorus pool sizes and uptake. The phosphorus dynamic was followed in a CO2-manipulation mesocosm experiment in the Storfjarden (western Gulf of Finland, Baltic Sea) in summer 2012 and was also studied in the surrounding fjord water. In all mesocosms as well as in surface waters of Storfjarden, dissolved organic phosphorus (DOP) concentrations of 0.26aEuro-+/- aEuro-0.03 and 0.23aEuro-+/- aEuro-0.04aEuro-A mu molaEuro-L-1, respectively, formed the main fraction of the total P-pool (TP), whereas phosphate (PO4) constituted the lowest fraction with mean concentration of 0.15aEuro-A +/- aEuro-0.02 in the mesocosms and 0.17aEuro-A +/- aEuro-0.07aEuro-A mu molaEuro-L-1 in the fjord. Transformation of PO4 into DOP appeared to be the main pathway of PO4 turnover. About 82aEuro-% of PO4 was converted into DOP whereby only 18aEuro-% of PO4 was transformed into particulate phosphorus (PP). PO4 uptake rates measured in the mesocosms ranged between 0.6 and 3.9aEuro-nmolaEuro-L(-1)aEuro-h(-1). About 86aEuro-% of them was realized by the size fraction < aEuro-3aEuro-A mu m. Adenosine triphosphate (ATP) uptake revealed that additional P was supplied from organic compounds accounting for 25-27aEuro-% of P provided by PO4 only. CO2 additions did not cause significant changes in phosphorus (P) pool sizes, DOP composition, and uptake of PO4 and ATP when the whole study period was taken into account. However, significant short-term effects were observed for PO4 and PP pool sizes in CO2 treatments > aEuro-1000aEuro-A mu atm during periods when phytoplankton biomass increased. In addition, we found significant relationships (e.g., between PP and Chl a) in the untreated mesocosms which were not observed under high fCO(2) conditions. Consequently, it can be hypothesized that the relationship between PP formation and phytoplankton growth changed with CO2 elevation. It can be deduced from the results, that visible effects of CO2 on P pools are coupled to phytoplankton growth when the transformation of PO4 into POP was stimulated. The transformation of PO4 into DOP on the other hand does not seem to be affected. Additionally, there were some indications that cellular mechanisms of P regulation might be modified under CO2 elevation changing the relationship between cellular constituents.
Introduction
Genes involved in body weight regulation that were previously investigated in genome-wide association studies (GWAS) and in animal models were target-enriched followed by massive parallel next generation sequencing.
Methods
We enriched and re-sequenced continuous genomic regions comprising FTO, MC4R, TMEM18, SDCCAG8, TKNS, MSRA and TBC1D1 in a screening sample of 196 extremely obese children and adolescents with age and sex specific body mass index (BMI) >= 99th percentile and 176 lean adults (BMI <= 15th percentile). 22 variants were confirmed by Sanger sequencing. Genotyping was performed in up to 705 independent obesity trios (extremely obese child and both parents), 243 extremely obese cases and 261 lean adults.
Results and Conclusion
We detected 20 different non-synonymous variants, one frame shift and one nonsense mutation in the 7 continuous genomic regions in study groups of different weight extremes. For SNP Arg695Cys (rs58983546) in TBC1D1 we detected nominal association with obesity (p(TDT) = 0.03 in 705 trios). Eleven of the variants were rare, thus were only detected heterozygously in up to ten individual(s) of the complete screening sample of 372 individuals. Two of them (in FTO and MSRA) were found in lean individuals, nine in extremely obese. In silico analyses of the 11 variants did not reveal functional implications for the mutations. Concordant with our hypothesis we detected a rare variant that potentially leads to loss of FTO function in a lean individual. For TBC1D1, in contrary to our hypothesis, the loss of function variant (Arg443Stop) was found in an obese individual. Functional in vitro studies are warranted.
We elicited the production of various types of relative clauses in a group of German-speaking children with specific language impairment (SLI) and typically developing controls in order to test the movement optionality account of grammatical difficulty in SLI. The results show that German-speaking children with SLI are impaired in relative clause production compared to typically developing children. The alternative structures that they produce consist of simple main clauses, as well as nominal and prepositional phrases produced in isolation, sometimes contextually appropriate, and sometimes not. Crucially for evaluating the movement optionality account, children with SLI produce very few instances of embedded clauses where the relative clause head noun is pronounced in situ; in fact, such responses are more common among the typically developing child controls. These results underscore the difficulty German-speaking children with SLI have with structures involving movement, but provide no specific support for the movement optionality account.
Comparative literature on institutional reforms in multi-level systems proceeds from a global trend towards the decentralization of state functions. However, there is only scarce knowledge about the impact that decentralization has had, in particular, upon the sub-central governments involved. How does it affect regional and local governments? Do these reforms also have unintended outcomes on the sub-central level and how can this be explained? This article aims to develop a conceptual framework to assess the impacts of decentralization on the sub-central level from a comparative and policyoriented perspective. This framework is intended to outline the major patterns and models of decentralization and the theoretical assumptions regarding de-/re-centralization impacts, as well as pertinent cross-country approaches meant to evaluate and compare institutional reforms. It will also serve as an analytical guideline and a structural basis for all the country-related articles in this Special Issue.
Although there is ample evidence linking insecure attachment styles and intimate partner violence (IPV), little is known about the psychological processes underlying this association, especially from the victim’s perspective. The present study examined how attachment styles relate to the experience of sexual and psychological abuse, directly or indirectly through destructive conflict resolution strategies, both self-reported and attributed to their opposite-sex romantic partner. In an online survey, 216 Spanish undergraduates completed measures of adult attachment style, engagement and withdrawal conflict resolution styles shown by self and partner, and victimization by an intimate partner in the form of sexual coercion and psychological abuse. As predicted, anxious and avoidant attachment styles were directly related to both forms of victimization. Also, an indirect path from anxious attachment to IPV victimization was detected via destructive conflict resolution strategies. Specifically, anxiously attached participants reported a higher use of conflict engagement by themselves and by their partners. In addition, engagement reported by the self and perceived in the partner was linked to an increased probability of experiencing sexual coercion and psychological abuse. Avoidant attachment was linked to higher withdrawal in conflict situations, but the paths from withdrawal to perceived partner engagement, sexual coercion, and psychological abuse were non-significant. No gender differences in the associations were found. The discussion highlights the role of anxious attachment in understanding escalating patterns of destructive conflict resolution strategies, which may increase the vulnerability to IPV victimization.
School shooters are often described as narcissistic, but empirical evidence is scant. To provide more reliable and detailed information, we conducted an exploratory study, analyzing police investigation files on seven school shootings in Germany, looking for symptoms of narcissistic personality disorder as defined by the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) in witnesses' and offenders' reports and expert psychological evaluations. Three out of four offenders who had been treated for mental disorders prior to the offenses displayed detached symptoms of narcissism, but none was diagnosed with narcissistic personality disorder. Of the other three, two displayed narcissistic traits. In one case, the number of symptoms would have justified a diagnosis of narcissistic personality disorder. Offenders showed low and high self-esteem and a range of other mental disorders. Thus, narcissism is not a common characteristic of school shooters, but possibly more frequent than in the general population. This should be considered in developing adequate preventive and intervention measures.
This doctoral thesis seeks to elaborate how Wittgenstein’s very sparse writings on ethics and ethical thought, together with his later work on the more general problem of normativity and his approach to philosophical problems as a whole, can be applied to contemporary meta-ethical debates about the nature of moral thought and language and the sources of moral obligation. I begin with a discussion of Wittgenstein’s early “Lecture on Ethics”, distinguishing the thesis of a strict fact/value dichotomy that Wittgenstein defends there from the related thesis that all ethical discourse is essentially and intentionally nonsensical, an attempt to go beyond the limits of sense. The first chapter discusses and defends Wittgenstein’s argument that moral valuation always goes beyond any ascertaining of fact; the second chapter seeks to draw out the valuable insights from Wittgenstein’s (early) insistence that value discourse is nonsensical while also arguing that this thesis is ultimately untenable and also incompatible with later Wittgensteinian understanding of language. On the basis of this discussion I then take up the writings of the American philosopher Cora Diamond, who has worked out an ethical approach in a very closely Wittgensteinian spirit, and show how this approach shares many of the valuable insights of the moral expressivism and constructivism of contemporary authors such as Blackburn and Korsgaard while suggesting a way to avoid some of the problems and limitations of their approaches. Subsequently I turn to a criticism of the attempts by Lovibond and McDowell to enlist Wittgenstein in the support for a non-naturalist moral realism. A concluding chapter treats the ways that a broadly Wittgensteinian conception expands the subject of metaethics itself by questioning the primacy of discursive argument in moral thought and of moral propositions as the basic units of moral belief.
Die vorliegende Arbeit beschäftigt sich mit Qualitätsmanagementsystemen in Nonprofit-Organisationen. Sie stellt dabei das Spannungsfeld verschiedener Akteursinteressen innerhalb von Nonprofit-Organisationen in den Vordergrund. Dies erfolgt anhand des mikropolitischen Ansatzes, der allen Akteuren innerhalb einer Organisation eigene Interessen zugesteht, die sie durch Taktiken und Strategien in Machtkämpfen versuchen durchzusetzen.
Untersucht wird der Prozess der Entstehung und Evaluation von konkreten Maßnahmen, den sogenannten Qualitätszielen, und den Einfluss von pädagogischen Mitarbeitenden auf deren Formulierung. Dies erfolgt anhand einer Einzelfallstudie. Mithilfe von qualitativen Interviews wurde untersucht, inwieweit pädagogische Mitarbeitende die Einflussmöglichkeiten des Qualitätsmanagementsystems zur strategischen Organisationsentwicklung und Durchsetzung eigener Interessen nutzen.
Die Ergebnisse zeigen, dass es zwei Typen von Mitarbeitenden gibt, aktive und passive, die entweder einen Machtgewinn oder -verlust erleben. Aufgrund der kooperativen Art der Kommunikation und Entscheidungsfindung sowie kaum divergierenden Interessen zwischen den verschiedenen Akteuren bleiben die vorhandenen Einflussmöglichkeiten im Sinne von organisationsinternen Machtkämpfen und mikropolitischen Taktiken bisher jedoch weitestgehend ungenutzt. Diese Falleigenschaften erklären, wieso der mikropolitische Ansatz bei der Analyse nicht zu den antizipierten Resultaten geführt hat.
HPI Future SOC Lab
(2016)
The “HPI Future SOC Lab” is a cooperation of the Hasso Plattner Institute (HPI) and industrial partners. Its mission is to enable and promote exchange and interaction between the research community and the industrial partners.
The HPI Future SOC Lab provides researchers with free of charge access to a complete infrastructure of state of the art hard and software. This infrastructure includes components, which might be too expensive for an ordinary research environment, such as servers with up to 64 cores and 2 TB main memory. The offerings address researchers particularly from but not limited to the areas of computer science and business information systems. Main areas of research include cloud computing, parallelization, and In-Memory technologies.
This technical report presents results of research projects executed in 2016. Selected projects have presented their results on April 5th and November 3th 2016 at the Future SOC Lab Day events.
We do magnetohydrodynamic (MHD) simulations of local box models of turbulent Interstellar Medium (ISM) and analyse the process of amplification and saturation of mean magnetic fields with methods of mean field dynamo theory. It is shown that the process of saturation of mean fields can be partially described by the prolonged diffusion time scales in presence of the dynamically significant magnetic fields. However, the outward wind also plays an essential role in the saturation in higher SN rate case. Algebraic expressions for the back reaction of the magnetic field onto the turbulent transport coefficients are derived, which allow a complete description of the nonlinear dynamo. We also present the effects of dynamically significant mean fields on the ISM configuration and pressure distribution. We further add the cosmic ray component in the simulations and investigate the kinematic growth of mean fields with a dynamo perspective.
Jeden Tag werden unzählige Mengen an medizinischen Patientendaten in Krankenhäusern und Arztpraxen digital gespeichert. Für Forschungszwecke werden diese Daten bisher größtenteils nicht verwendet. Ziel dieser Arbeit ist es täglich anfallende anonymisierte Patientendaten, die aus einer Praxis für ganzheitliche Innere Medizin stammen, zu analysieren. Aufgrund mangelnder Kooperation seitens des Anbieters der Praxissoftware konnten die Patientendaten nicht automatisch extrahiert werden. Daher wurde eine Auswahl an Diagnosen und anthropometrischen Parametern manuell in eine Datenbank übertragen. Informationen über die Behandlung wurden dabei nicht berücksichtigt. Data-Mining Verfahren ermöglichen die Forschung auf der Grundlage von alltäglichen Patientendaten. Durch die Anwendung maschinellen Lernens kann Präventionsmedizin und die Überwachung von Behandlungsverläufen unterstützt werden.
Das Potenzial der Analyse dieser sonst weitgehend ungenutzten Daten wird anhand von Untersuchungen zur Komorbidität verdeutlicht. Dabei zeigt sich, dass einerseits das Metabolische Syndrom und dessen Komponenten zusammen mit Krebserkrankungen ein Cluster bilden und andererseits psychosomatische Störungen vermehrt mit Autoimmunerkrankungen der Schilddrüse auftreten. Außerdem wird eine noch nicht schulmedizinisch anerkannte Stoffwechselerkrankung, die Hämopyrrollaktamurie (HPU) untersucht. Diese lässt sich durch eine vermehrte Ausscheidung von Pyrrolen im Urin nachweisen. Bezüglich der Patienten bei denen ein HPU-Test vorliegt, weisen 84 % einen erhöhten Titer auf. Diese Beobachtung steht im Widerspruch zur vorherigen Annahme, dass in etwa 10 % der Bevölkerung von HPU betroffen sind.
Präventives Handeln ermöglicht es Gesundheit zu erhalten. Zu diesem Zweck ist es notwen- dig Krankheiten möglichst früh zu erkennen. In dieser Studie können Entscheidungsbaum-Modelle die Hashimoto Thyreoiditis mit einer Genauigkeit von 87.5 % bei einem Patienten diagnostizieren. Defizite durch die fehlenden Informationen über die medikamentöse Behandlung werden anhand des Modells zur Vorhersage von Hypothyreoiditis (Genauigkeit von 60.9 %) aufgezeigt.
Mit Hilfe von STATIS, das auf einer Erweiterung der Hauptkomponentenanalyse basiert, die es ermöglicht mehrere Tabellen simultan zu vergleichen, wurde der Behandlungsverlauf von 20 Patienten über einen Zeitraum von fünf Jahren überwacht. Anhand von Hypertonie wird gezeigt, dass sich sich die Patenten bezüglich Ihrer Laborwerte voneinander unterscheiden und sich Muster für Krankheiten erkennen lassen.
Diese Arbeit demonstriert den Nutzen, der durch die vermehrte Analyse alltäglicher hochdimensionaler und heterogener Daten erbracht werden kann.
Design and Implementation of service-oriented architectures imposes a huge number of research questions from the fields of software engineering, system analysis and modeling, adaptability, and application integration. Component orientation and web services are two approaches for design and realization of complex web-based system. Both approaches allow for dynamic application adaptation as well as integration of enterprise application.
Commonly used technologies, such as J2EE and .NET, form de facto standards for the realization of complex distributed systems. Evolution of component systems has lead to web services and service-based architectures. This has been manifested in a multitude of industry standards and initiatives such as XML, WSDL UDDI, SOAP, etc. All these achievements lead to a new and promising paradigm in IT systems engineering which proposes to design complex software solutions as collaboration of contractually defined software services.
Service-Oriented Systems Engineering represents a symbiosis of best practices in object-orientation, component-based development, distributed computing, and business process management. It provides integration of business and IT concerns.
The annual Ph.D. Retreat of the Research School provides each member the opportunity to present his/her current state of their research and to give an outline of a prospective Ph.D. thesis. Due to the interdisciplinary structure of the research school, this technical report covers a wide range of topics. These include but are not limited to: Human Computer Interaction and Computer Vision as Service; Service-oriented Geovisualization Systems; Algorithm Engineering for Service-oriented Systems; Modeling and Verification of Self-adaptive Service-oriented Systems; Tools and Methods for Software Engineering in Service-oriented Systems; Security Engineering of Service-based IT Systems; Service-oriented Information Systems; Evolutionary Transition of Enterprise Applications to Service Orientation; Operating System Abstractions for Service-oriented Computing; and Services Specification, Composition, and Enactment.
Mit der Patientenmobilitätsrichtlinie (2011/24/EU) wurde eine verbindliche gesetzliche Grundlage geschaffen, im Bereich der hochspezialisierten Gesundheitsversorgung freiwillig und in strukturierter Form in europäischen Referenznetzwerken (ERN) von Gesundheits-dienstleistern und Fachzentren zusammenzuarbeiten. Dabei kommt dem Austausch von Fachwissen eine besondere Bedeutung zu. Diese qualitative Studie geht der Frage nach, wel-che wesentlichen Faktoren den Informations- und Wissensaustausch sowie das Lernen in Netzwerken beeinflussen und wie diese gefördert werden können. Es werden Netzwerkkoor-dinatoren und deren steuernde Einheiten in den hochspezialisierten Versorgungsbereichen Krebs und Seltene Erkrankungen in Deutschland und in Frankreich sowie auf europäischer Ebene befragt. Die Studie wird durch einen Literaturvergleich von bi- und trilateralen Ge-sundheitskooperationen mit multilateralen Netzwerken ergänzt. Für die ERN wird die zentra-le Bedeutung der digitalen Medien und Technologien herausgearbeitet sowie die Empfeh-lung ausgesprochen, die ERN ein systematisches Wissensverwendungs- und -generierungskonzept erarbeiten zu lassen. Durch die zukünftigen ERN wird die vernetzte Informationsgesellschaft Einzug in die medizinische Praxis halten.
This paper deals with the teaching of grammar in the English as a foreign language (EFL) classroom. In this context, a course book (English G 21 A2) is examined in regard to whether it is compatible with current theories about second language acquisition (SLA).
At the beginning of this paper, views on grammar teaching from the past and the present are summarized and this is followed by an analysis of the current curriculum concerning its guidelines for grammar teaching in the foreign language classroom. This analysis concludes that the curriculum of Brandenburg hardly gives any recommendations regarding the question of which grammatical phenomena should to be taught. This explains, at least partly, the important position course books take in the foreign language classroom. Teachers use them as a source of material as well has a guideline for which topics can be taught and in which order.
The following part gives an overview of cognitive models of SLA and foreign language teaching, among others Krashen’s Monitor Hypothesis, R. Ellis’ Weak Interface Model and Pienemann’s Processability Theory. On the basis of these models criteria for the ideal design of a course book, which would support grammar teaching according to current findings, are developed. Among those criteria are the offering of a lot of input in the target language, provision of practice activities and consciousness-raising activities, taking into consideration the sequence of acquisition and the provision of a diagnostic tool which enables the students to find out in which areas of the target language they need to improve. Furthermore, the inclusion of opportunities for (individual) revision is regarded as essential. All of those criteria are of course given under the reservation that the influence of course books on the happenings in the classroom is restricted as the final decisions are made by the teacher in the teaching situation.
In the analysis, one communicative intention which is usually a topic in the English lessons between the third and sixth year of learning is focused on. This communicative intention is talking about the future. First, the possibilities to express futurity in the English language are analysed and reduced for the use in teaching. The chosen course book is then described and analysed and the way the book deals with the topic of talking about the future is compared to the criteria which where specified earlier in the paper. This comparison showed that the book is compatible with SLA theories in many ways (e.g. concerning the explanations of grammatical structures) but that there is still room for improvement (e.g. concerning the amount of input and the number of consciousness-raising activities).
Faktor Mensch
(2016)
Eine Krisensituation ist eine Umbruchssituation. Sie kann als Chance, als Herausforderung sowie im Sinne einer SCHUMPETER’SCHEN „schöpferischen Zerstörung“ als Ausgangspunkt von bedeutsamen Veränderungen und neuen Entwicklungsmöglichkeiten begriffen werden. Die Krisensituation der 1970er und 1980er Jahre bildet dahingehend durch ihre Einzigartigkeit einen herausragenden wirtschaftshistorischen Untersuchungsgegenstand. Für die westeuropäischen Staaten waren es nicht nur Jahre einer, nach der außergewöhnlich langen Boomzeit der „Wirtschaftswunderjahre“, problematischen sozialen und wirtschaftliche Situation. Es war auch eine Zeit eines bedeutungsvollen und beschleunigten Wandels. Die Gleichzeitigkeit vieler Veränderungen, das zeitliche Zusammentreffen von konjunkturellen und strukturellen Problemlagen sowie die äußerst kritische Situation an den westeuropäischen Arbeitsmärkten bildete eine multiple Krisensituation. Deren Auswirkungen waren weitreichender, als es von den Zeitgenossen erahnt werden konnte. Es gab nicht nur Änderungen im (wirtschafts-)politischen Makrogefüge vieler Volkswirtschaften, auch bedeutende Einflüsse waren auf der Mikroebene feststellbar. Marktorientierte Unternehmen mussten sich auf die neue Situation einstellen und im Rahmen einer Neupositionierung von Betriebsstrategien, organisatorischen Umgestaltungen und einer stärkeren Ressourcenorientierung betriebswirtschaftlich handeln. Das schien letztlich zu einer stärkeren Beachtung und Entwicklung der in den Unternehmen vorhandenen humanen und sozialen Ressourcen zu führen.
Diese Arbeit stellt die Hypothese auf, dass umfassende organisatorische Veränderungen und strategische Neupositionierungen, insbesondere die effektivere Nutzung sowie der intensive Auf- und Ausbau betriebsinterner Personalressourcen Unternehmen maßgeblich halfen, die Krisensituation der 1970er und 1980er Jahre besser und nachhaltiger überwinden zu können. Anders als die bisherige wirtschaftshistorische Forschungsliteratur nimmt diese Dissertation nicht die makroökonomisch Perspektive in den Fokus, sondern untersucht die Hypothese anhand mehrerer Unternehmensfallstudien. Ausgewählt sind drei Großunternehmen der westeuropäischen Elektroindustrie. Diese Arbeit liefert mit dieser Untersuchung einen weiteren Baustein zur wirtschaftshistorischen Annäherung an die 1970er und 1980er Jahre und leistet ebenso einen Beitrag zur Fortschreibung der Firmengeschichte der drei Unternehmen.
Die Elektrobranche fand bisher wirtschaftshistorisch nur wenig Beachtung, dennoch ist sie ein gutes Beispiel für die umfassende Veränderungssituation jener Jahre. Entsprechende Sekundärquellen sind für diesen Zeitraum für die drei Unternehmen kaum vorhanden. Aus diesem Grund bildet eine Vielzahl von Archivalien das Fundament dieser Arbeit. Sie werden als Primärquellen aus den jeweiligen Unternehmensarchiven als Basis der Fallanalyse herangezogen. Mit Hilfe zahlreicher Dokumente des betrieblichen „Alltagsgeschäfts“, wie beispielsweise Daten des betrieblichen Personal- und Rechnungswesens, Protokolle von Sitzungen der Arbeitsnehmervertreter, des Aufsichtsrats oder des Vorstands sowie interne Strategiepapiere und Statistiken, wird nicht nur der anfangs aufgestellten Hypothese nachgegangen, sondern auch mehrerer sich aus ihr ergebende Fragenkomplexe. Im Rahmen derer wird untersucht, wie die Unternehmen – die Beschäftigten, die Leitungsebenen und die Aufsichtsräte – auf die Krisensituation reagierten, ob sie ggf. ihrerseits Einfluss darauf zu nehmen versuchten und welche betriebswirtschaftlichen Schlüsse daraus gezogen wurden. Es wird hinterfragt, ob eine stärkere Ressourcenorientierung wirklich eine neue Strategieperspektive bot und es diesbezüglich zu einer stärkeren Beachtung humaner und sozialer Ressourcen im Unternehmen kam. Diese Arbeit untersucht, ob gezielt zur Krisenüberwindung in diese Ressourcen investiert wurde und diese Investitionen halfen, die Krisensituation erfolgreich zu überstehen und nachhaltig den Unternehmenserfolg zu sichern.
The Milky Way is only one out of billions of galaxies in the universe. However, it is a special galaxy because it allows to explore the main mechanisms involved in its evolution and formation history by unpicking the system star-by-star. Especially, the chemical fingerprints of its stars provide clues and evidence of past events in the Galaxy’s lifetime. These information help not only to decipher the current structure and building blocks of the Milky Way, but to learn more about the general formation process of galaxies.
In the past decade a multitude of stellar spectroscopic Galactic surveys have scanned millions of stars far beyond the rim of the solar neighbourhood. The obtained spectroscopic information provide unprecedented insights to the chemo-dynamics of the Milky Way. In addition analytic models and numerical simulations of the Milky Way provide necessary descriptions and predictions suited for comparison with observations in order to decode the physical properties that underlie the complex system of the Galaxy.
In the thesis various approaches are taken to connect modern theoretical modelling of galaxy formation and evolution with observations from Galactic stellar surveys. With its focus on the chemo-kinematics of the Galactic disk this work aims to determine new observational constraints on the formation of the Milky Way providing also proper comparisons with two different models. These are the population synthesis model TRILEGAL based on analytical distribution functions, which aims to simulate the number and distribution of stars in the Milky Way and its different components, and a hybrid model (MCM) that combines an N-body simulation of a Milky Way like galaxy in the cosmological framework with a semi-analytic chemical evolution model for the Milky Way. The major observational data sets in use come from two surveys, namely the “Radial Velocity Experiment” (RAVE) and the “Sloan Extension for Galactic Understanding and Exploration” (SEGUE).
In the first approach the chemo-kinematic properties of the thin and thick disk of the Galaxy as traced by a selection of about 20000 SEGUE G-dwarf stars are directly compared to the predictions by the MCM model. As a necessary condition for this, SEGUE's selection function and its survey volume are evaluated in detail to correct the spectroscopic observations for their survey specific selection biases. Also, based on a Bayesian method spectro-photometric distances with uncertainties below 15% are computed for the selection of SEGUE G-dwarfs that are studied up to a distance of 3 kpc from the Sun.
For the second approach two synthetic versions of the SEGUE survey are generated based on the above models. The obtained synthetic stellar catalogues are then used to create mock samples best resembling the compiled sample of observed SEGUE G-dwarfs. Generally, mock samples are not only ideal to compare predictions from various models. They also allow validation of the models' quality and improvement as with this work could be especially achieved for TRILEGAL. While TRILEGAL reproduces the statistical properties of the thin and thick disk as seen in the observations, the MCM model has shown to be more suitable in reproducing many chemo-kinematic correlations as revealed by the SEGUE stars. However, evidence has been found that the MCM model may be missing a stellar component with the properties of the thick disk that the observations clearly show. While the SEGUE stars do indicate a thin-thick dichotomy of the stellar Galactic disk in agreement with other spectroscopic stellar studies, no sign for a distinct metal-poor disk is seen in the MCM model.
Usually stellar spectroscopic surveys are limited to a certain volume around the Sun covering different regions of the Galaxy’s disk. This often prevents to obtain a global view on the chemo-dynamics of the Galactic disk. Hence, a suitable combination of stellar samples from independent surveys is not only useful for the verification of results but it also helps to complete the picture of the Milky Way. Therefore, the thesis closes with a comparison of the SEGUE G-dwarfs and a sample of RAVE giants. The comparison reveals that the chemo-kinematic relations agree in disk regions where the samples of both surveys show a similar number of stars. For those parts of the survey volumes where one of the surveys lacks statistics they beautifully complement each other. This demonstrates that the comparison of theoretical models on the one side, and the combined observational data gathered by multiple surveys on the other side, are key ingredients to understand and disentangle the structure and formation history of the Milky Way.
Die vorliegende explorative empirische Untersuchung muslimischer Frauengruppen leistet einen Beitrag zur Erforschung des religiösen Wandels im religiösen Feld in Deutschland. Zum einen werden damit erstmals qualitative Daten zu religiösen Gruppen muslimischer Frauen erhoben. Zum anderen liefern die analysierten Anlässe der Gruppengründung und die Gruppenziele Einblicke in die relevanten Themen des religiös-muslimischen Engagements im Zeitverlauf. Gemäß der explorativen Konzeption interessiert sich diese Studie insbesondere für die Vielfalt muslimischer Frauengruppen in Deutschland. Es wurde gefragt, welche Selbstbeschreibungen als muslimische Frauengruppen sich derzeit erkennen lassen? Dazu wurden thematische Leitfadeninterviews mit Ansprechpartnerinnen muslimischer Frauengruppen im religiösen Feld (2006-2011) durchgeführt.
Die Gründungen der zwölf untersuchten muslimischen Frauengruppen lagen im Zeitraum von 1978 bis 2009. Dies umfasst im Hinblick auf das muslimisch-religiöse Engagement Phasen mit unterschiedlichen Schwerpunkten, die von der Verfestigung der religiösen Strukturen über den Kampf um rechtliche Gleichstellung als religiöse Minderheit bis zu einer Auseinandersetzung mit der staatlichen Islampolitik reichen. Die ältesten der untersuchten Gruppen reflektieren in ihrem historischen Verlauf den Aufbau der religiösen Strukturen, indem sie zunächst Räume für sich in den Gemeinden schufen. Diese füllten sie in Form von religiösen Bildungsprozessen und zwar indem sie einander an ihren Kenntnissen teilhaben ließen und gemeinsam die religiöse Quelle erschlossen. Andere Gruppen schlossen sich zusammen, um von den Kenntnissen religiöser Expertinnen zu profitieren, wieder andere etablierten Angebote, die über den eigenen Gruppenzusammenhang hinausreichten. Mit dieser Ausrichtung der Weltgestaltung ging auch die Gründung einer Organisation, d.h. ein Wandel der Sozialform einher.
Die Ergebnisse konstatieren eine Kontingenz hinsichtlich der Selbstzuordnung muslimische Frauengruppe. Es handelt sich um historisch spezifische Selbstzuschreibungen, die Ausdruck eines religiösen Wandels im muslimisch-religiösen Feld initiiert von muslimischen Frauen sind. Zentrales Ergebnis ist hier, dass die Gruppen zwar hinsichtlich ihrer Formen heterogen sind, allerdings eine Verbindungslinie in ihren Kernideen als Frauengruppen- und Organisationen besteht. Es zeigt sich durch alle Phasen des muslimisch-religiösen Engagements im religiösen Feld ein hohes Interesse an religiösen Bildungsthemen seitens muslimischer Frauen. Diese sind verbunden mit der Auseinandersetzung mit dem religiösen Geschlechterverhältnis.
Die Aufmerksamkeit, die das religiöse Geschlechterverhältnis im Kontext des Institutionalisierungs- und Partizipationsprozess des Islam im politischen Feld derzeit besitzt, kann einerseits als spezifisch gelten. Andererseits zeigen historische Kontextualisierungen mit der religiösen Frauenbewegung im 19. Jahrhundert, dass auch hier über religiöse Geschlechterbilder Partizipationsfragen verhandelt wurden.
Die Ergebnisse dieser Studie belegen die Relevanz von religiösen Gruppen innerhalb religiöser Wandlungsprozesse. Weiterhin liefern sie neue Erkenntnisse hinsichtlich des Verhältnisses von religiöser Individualisierung und Gruppenbindung: Muslimische Frauen vergemeinschaften sich aus religiösen Bildungszwecken innerhalb von religiösen Gruppen und behandeln dabei Themen ihre weibliche religiöse Identität und die religiöse Lebensführung als Frau betreffend und dies stärkt ihre individuelle religiöse Bindung.
In the current paradigm of cosmology, the formation of large-scale structures is mainly driven by non-radiating dark matter, making up the dominant part of the matter budget of the Universe. Cosmological observations however, rely on the detection of luminous galaxies, which are biased tracers of the underlying dark matter. In this thesis I present cosmological reconstructions of both, the dark matter density field that forms the cosmic web, and cosmic velocities, for which both aspects of my work are delved into, the theoretical formalism and the results of its applications to cosmological simulations and also to a galaxy redshift survey.The foundation of our method is relying on a statistical approach, in which a given galaxy catalogue is interpreted as a biased realization of the underlying dark matter density field. The inference is computationally performed on a mesh grid by sampling from a probability density function, which describes the joint posterior distribution of matter density and the three dimensional velocity field. The statistical background of our method is described in Chapter ”Implementation of argo”, where the introduction in sampling methods is given, paying special attention to Markov Chain Monte-Carlo techniques. In Chapter ”Phase-Space Reconstructions with N-body Simulations”, I introduce and implement a novel biasing scheme to relate the galaxy number density to the underlying dark matter, which I decompose into a deterministic part, described by a non-linear and scale-dependent analytic expression, and a stochastic part, by presenting a negative binomial (NB) likelihood function that models deviations from Poissonity. Both bias components had already been studied theoretically, but were so far never tested in a reconstruction algorithm. I test these new contributions againstN-body simulations to quantify improvements and show that, compared to state-of-the-art methods, the stochastic bias is inevitable at wave numbers of k≥0.15h Mpc^−1 in the power spectrum in order to obtain unbiased results from the reconstructions. In the second part of Chapter ”Phase-Space Reconstructions with N-body Simulations” I describe and validate our approach to infer the three dimensional cosmic velocity field jointly with the dark matter density. I use linear perturbation theory for the large-scale bulk flows and a dispersion term to model virialized galaxy motions, showing that our method is accurately recovering the real-space positions of the redshift-space distorted galaxies. I analyze the results with the isotropic and also the two-dimensional power spectrum.Finally, in Chapter ”Phase-space Reconstructions with Galaxy Redshift Surveys”, I show how I combine all findings and results and apply the method to the CMASS (for Constant (stellar) Mass) galaxy catalogue of the Baryon Oscillation Spectroscopic Survey (BOSS). I describe how our method is accounting for the observational selection effects inside our reconstruction algorithm. Also, I demonstrate that the renormalization of the prior distribution function is mandatory to account for higher order contributions in the structure formation model, and finally a redshift-dependent bias factor is theoretically motivated and implemented into our method. The various refinements yield unbiased results of the dark matter until scales of k≤0.2 h Mpc^−1in the power spectrum and isotropize the galaxy catalogue down to distances of r∼20h^−1 Mpc in the correlation function. We further test the results of our cosmic velocity field reconstruction by comparing them to a synthetic mock galaxy catalogue, finding a strong correlation between the mock and the reconstructed velocities. The applications of both, the density field without redshift-space distortions, and the velocity reconstructions, are very broad and can be used for improved analyses of the baryonic acoustic oscillations, environmental studies of the cosmic web, the kinematic Sunyaev-Zel’dovic or integrated Sachs-Wolfe effect.
Trotz aller Bemühungen um Chancengleichheit entscheiden sich weitaus weniger Frauen als Männer für einen MINT-bezogenen Studiengang oder Beruf. Auch in der heranwachsenden Generation deutscher Schülerinnen liegt die Motivation einen naturwissenschaftlichen Beruf zu ergreifen unter dem Durchschnitt deutscher Schüler. Schulleistungsuntersuchungen belegen, dass vor allem Schülerinnen der Sekundarstufe I ein deutlich geringeres Interesse an Fächern der Naturwissenschaften, insbesondere Physik, aufweisen als gleichaltrige Jungen. Aus diesem Grund widmet sich die vorliegende Untersuchung der Frage, ob es bereits am Ende der Grundschulzeit einen geschlechtstypischen Unterschied des Interesses am Fach Physik bei Schülerinnen und Schüler gibt. Teil der schriftlichen Befragung wurden Schülerinnen und Schüler der sechsten Klasse des Landes Brandenburg (N=235). Die Datenerhebung erfolgte mittels eines eigens entwickelten Messinstrumentes (.52≤α≤.79). Es lassen sich mit Effektstärken von |d|_1=.38, |d|_2=.27, |d|_3=.18 sowie |d|_4=.28 Unterschiede mit einer teils geringen praktischen Bedeutsamkeit zugunsten der befragten Jungen finden. Zudem deuten die Ergebnisse darauf hin, dass sowohl Jungen als auch Mädchen, die der Ansicht sind, dass das eigene Geschlecht generell mehr Interesse an Physik aufweist, tatsächlich selbst mehr Interesse als das jeweils andere Geschlecht haben. Eine Interpretation der Ergebnisse sowie Limitationen und Implikationen der Untersuchung werden diskutiert.
In the past decades, development cooperation (DC) led by conventional bi- and multilateral donors has been joined by a large number of small, private or public-private donors. This pluralism of actors raises questions as to whether or not these new donors are able to implement projects more or less effectively than their conventional counterparts. In contrast to their predecessors, the new donors have committed themselves to be more pragmatic, innovative and flexible in their development cooperation measures. However, they are also criticized for weakening the function of local civil society and have the reputation of being an intransparent and often controversial alternative to public services. With additional financial resources and their new approach to development, the new donors have been described in the literature as playing a controversial role in transforming development cooperation. This dissertation compares the effectiveness of initiatives by new and conventional donors with regard to the provision of public goods and services to the poor in the water and sanitation sector in India.
India is an emerging country but it is experiencing high poverty rates and poor water supply in predominantly rural areas. It lends itself for analyzing this research theme as it is currently being confronted by a large number of actors and approaches that aim to find solutions for these challenges .
In the theoretical framework of this dissertation, four governance configurations are derived from the interaction of varying actor types with regard to hierarchical and non-hierarchical steering of their interactions. These four governance configurations differ in decision-making responsibilities, accountability and delegation of tasks or direction of information flow. The assumption on actor relationships and steering is supplemented by possible alternative explanations in the empirical investigation, such as resource availability, the inheritance of structures and institutions from previous projects in a project context, gaining acceptance through beneficiaries (local legitimacy) as a door opener, and asymmetries of power in the project context.
Case study evidence from seven projects reveals that the actors' relationship is important for successful project delivery. Additionally, the results show that there is a systematic difference between conventional and new donors. Projects led by conventional donors were consistently more successful, due to an actor relationship that placed the responsibility in the hands of the recipient actors and benefited from the trust and reputation of a long-term cooperation. The trust and reputation of conventional donors always went along with a back-up from federal level and trickled down as reputation also at local level implementation. Furthermore, charismatic leaders, as well as the acquired structures and institutions of predecessor projects, also proved to be a positive influencing factor for successful project implementation.
Despite the mixed results of the seven case studies, central recommendations for action can be derived for the various actors involved in development cooperation. For example, new donors could fulfill a supplementary function with conventional donors by developing innovative project approaches through pilot studies and then implementing them as a supplement to the projects of conventional donors on the ground. In return, conventional donors would have to make room the new donors by integrating their approaches into already programs in order to promote donor harmonization. It is also important to identify and occupy niches for activities and to promote harmonization among donors on state and federal sides.
The empirical results demonstrate the need for a harmonization strategy of different donor types in order to prevent duplication, over-experimentation and the failure of development programs. A transformation to successful and sustainable development cooperation can only be achieved through more coordination processes and national self-responsibility.
Im Graduiertenkolleg NatRiskChange der Universität Potsdam und anderen Forschungseinrichtungen werden beobachtete sowie zukünftig mögliche Veränderungen von Naturgefahren untersucht. Teil des strukturierten Doktorandenprogramms sind sogenannte Task-Force-Einsätze, bei denen die Promovierende zeitlich begrenzt ein aktuelles Ereignis auswerten. Im Zuge dieser Aktivität wurde die Sturzflut vom 29.05.2016 in Braunsbach (Baden-Württemberg) untersucht.
In diesem Bericht werden erste Auswertungen zur Einordnung der Niederschläge, zu den hydrologischen und geomorphologischen Prozessen im Einzugsgebiet des Orlacher Bachs sowie zu den verursachten Schäden beleuchtet.
Die Region war Zentrum extremer Regenfälle in der Größenordnung von 100 mm innerhalb von 2 Stunden. Das 6 km² kleine Einzugsgebiet hat eine sehr schnelle Reaktionszeit, zumal bei vorgesättigtem Boden. Im steilen Bachtal haben mehrere kleinere und größere Hangrutschungen über 8000 m³ Geröll, Schutt und Schwemmholz in das Gewässer eingetragen und möglicherweise kurzzeitige Aufstauungen und Durchbrüche verursacht. Neben den großen Wassermengen mit einer Abflussspitze in einer Größenordnung von 100 m³/s hat gerade die Geschiebefracht zu großen Schäden an den Gebäuden entlang des Bachlaufs in Braunsbach geführt.
Die Gründung des Europäischen Stabilitätsmechanismus (ESM) durch einen völkerrechtlichen Vertrag außerhalb der EU-Verträge ist mit mehreren Nachteilen verbunden. So schwächt die Zersplitterung der Rechtsquellen die europäischen Institutionen und deren Legitimation. Auch kann der ESM nicht ohne weiteres auf die Strukturen und das Personal der Europäischen Kommission zurückgreifen. Daher ist eine Integration des ESM in das Gemeinschaftsrecht sinnvoll. Dies setzt eine Rechtsgrundlage voraus. Die Arbeit kommt unter Berücksichtigung der deutschen und französischen Positionen sowie der einschlägigen Rechtsprechung des EuGH zu dem Ergebnis, dass die bestehenden EUVerträge keine Rechtsgrundlage für die Integration des ESM in das Gemeinschaftsrecht enthalten. Vor diesem Hintergrund ist eine Änderung des AEUV gemäß dem ordentlichen Vertragsänderungsverfahren unumgänglich. Damit sollte eine ausdrückliche Rechtsgrundlage für einen gemeinschaftsrechtlichen Stabilitätsmechanismus geschaffen werden. In der Arbeit wird ein konkreter Formulierungsvorschlag für eine derartige Rechtsgrundlage entwickelt, auf deren Basis der Rat mit einer Verordnung einen gemeinschaftsrechtlichen Stabilitätsmechanismus schaffen kann. Außerdem werden die wesentlichen Strukturprinzipien für den gemeinschaftsrechtlichen Stabilitätsmechanismus entwickelt, im Hinblick auf Trägerschaft, Governance, Finanzierung, demokratische Kontrolle und die verfügbaren Finanzhilfeinstrumente.
In der vorliegenden Arbeit wird die planetare Grenzschicht in Ny-Ålesund, Spitzbergen, sowohl bezüglich kleinskaliger („mikrometeorologischer“) Effekte als auch in ihrer Kopplung mit der Synoptik untersucht. Dazu werden verschiedene Beobachtungsdaten aus der Säule und in Bodennähe zusammengezogen und bewertet. Die so gewonnenen Datensätze werden dann zur Validierung eines nicht-hydrostatischen, regionalen Klimamodells genutzt. Weiterhin werden orographisch bedingte Einflüsse, die Untergrundbeschaffenheit und die lokale Heterogenität der Unterlage untersucht. Hierzu werden meteorologische Größen, wie die Variabilität der Temperatur und insbesondere die jährliche Windverteilung in Bodennähe untersucht und es erfolgt ein Vergleich von in-situ gemessenen turbulenten Flüssen von den Eddy-Kovarianz-Messkomplexen bei Ny-Ålesund und im Bayelva-Tal unter demselben Aspekt. Es zeigt sich, dass der Eddy-Kovarianz-Messkomplex im Bayelva-Tal sehr stark durch eine orographisch bedingte Kanalisierung der Strömung beeinflusst ist und sich nicht für Vergleiche mit regionalen Klimamodellen mit horizontalen Auflösungen von <1km eignet. Die hohe Bodenfeuchte im Bayelva-Tal führt zudem zu einem deutlich kleineren Bowen-Verhältnis, als es für diese Region zu erwarten ist. Der Eddy-Kovarianz-Messkomplex bei Ny-Ålesund erweist sich hingegen als geeigneter für solche Modellvergleiche, aufgrund der typischen, küstennahen Windverteilung und des repräsentativen Footprints. Letzteres wird durch die Bestimmung der Footprint-Klimatologie des Jahres 2013 mit einem aktuellen Footprint-Modell erarbeitet.
Weiterhin wird die Auswirkung von (Anti-) Zyklonen über den Archipel auf die zeitliche Variabilität der lokalen Grenzschichteigenschaften untersucht und bewertet. Dazu wird ein Zyklonen-Detektions-Algorithmus auf ERA-Interim-Reanalysedatensätze angewendet, wodurch die Häufigkeit von nahezu ideal konzentrischen Hoch- und die Tiefdruckgebieten für drei Jahre bestimmt wird. Aus dieser Verteilung werden insgesamt drei interessante Zeiträume zu verschiedenen Jahreszeiten ausgewählt und im Rahmen von Prozessstudien die lokalen bodennahen meteorologischen Messungen, der turbulente Austausch an der Oberfläche und die Grenzschichtdynamik in der Säule untersucht. Die zeitliche Variabilität der dynamischen Grenzschichtstabilität in der Säule wird anhand von zeitlich hoch aufgelösten vertikalen Profilen der Bulk-Richardson-Zahl aus Kompositprofilen aus Fernerkundungsinstrumenten (Radiometer, Wind-LIDAR) sowie Mastdaten (BSRN-Mast) untersucht und die Grenzschichthöhe ermittelt. Aus diesen Analysen ergibt sich eine deutliche Abhängigkeit der thermischen Stabilität beim Durchzug von Fronten, eine damit einhergehende erhebliche Abhängigkeit der Grenzschichtdynamik und der Grenzschichthöhe sowie des turbulenten Austauschs von der zeitlichen Variabilität der Windgeschwindigkeit in der Säule.
Auf Grundlage der Standortanalysen und Prozessstudien erfolgt ein Vergleich der bodennahen Messungen und den Beobachtungen aus der Säule, sowohl von den genannten Fernerkundungsinstrumenten als auch von In-situ-Messungen (Radiosonden) für den Zeitraum einer Radiosondierungskampagne mit dem nicht-hydrostatischen, regionalen Klimamodel WRF (ARW). Auf Grundlage der Fragestellung, inwieweit aktuelle Schemata die Grenzschichtcharakteristika in orographisch stark gegliedertem Gelände in der Arktis reproduzieren können, werden zwei Grenzschichtparametrisierungsschemata mit verschiedenen Ordnungen der Schließung validiert. Hierzu wird die zeitliche Variabilität der Temperatur, der Feuchte und des Windfeldes in der Säule bis 2000m in den Simulationen mit den Beobachtungsdaten vergleichen. Es wird gezeigt, dass durch Modifikation der Initialwertfelder eine sehr gute Übereinstimmung zwischen den Simulationen und den Beobachtungen bereits bei einer horizontalen Auflösung von 1km erreicht werden kann und die Wahl des Grenzschichtschemas nur untergeordneten Einfluss hat. Hieraus werden Ansätze der Weiterentwicklung der Parametrisierungen, aber auch Empfehlungen bezüglich der Initialwertfelder, wie der Landmaske und der Orographie, vorgeschlagen.
Background: Low back pain (LBP) is one of the world wide leading causes of limited activity and disability. Impaired motor control has been found to be one of the possible factors related to the development or persistence of LBP. In particularly, motor control strategies seemed to be altered in situations requiring reactive responses of the trunk counteracting sudden external forces. However, muscular responses were mostly assessed in (quasi) static testing situations under simplified laboratory conditions. Comprehensive investigations in motor control strategies during dynamic everyday situations are lacking. The present research project aimed to investigate muscular compensation strategies following unexpected gait perturbations in people with and without LBP. A novel treadmill stumbling protocol was tested for its validity and reliability to provoke muscular reflex responses at the trunk and the lower extremities (study 1). Thereafter, motor control strategies in response to sudden perturbations were compared between people with LBP and asymptomatic controls (CTRL) (study 2). In accordance with more recent concepts of motor adaptation to pain, it was hypothesized that pain may have profound consequences on motor control strategies in LBP. Therefore, it was investigated whether differences in compensation strategies were either consisting of changes local to the painful area at the trunk, or also being present in remote areas such as at the lower extremities.
Methods: All investigations were performed on a custom build split-belt treadmill simulating trip-like events by unexpected rapid deceleration impulses (amplitude: 2 m/s; duration: 100 ms; 200 ms after heel contact) at 1m/s baseline velocity. A total number of 5 (study 1) and 15 (study 2) right sided perturbations were applied during walking trials. Muscular activities were assessed by surface electromyography (EMG), recorded at 12 trunk muscles and 10 (study 1) respectively 5 (study 2) leg muscles. EMG latencies of muscle onset [ms] were retrieved by a semi-automatic detection method. EMG amplitudes (root mean square (RMS)) were assessed within 200 ms post perturbation, normalized to full strides prior to any perturbation [RMS%]. Latency and amplitude investigations were performed for each muscle individually, as well as for pooled data of muscles grouped by location. Characteristic pain intensity scores (CPIS; 0-100 points, von Korff) based on mean intensity ratings reported for current, worst and average pain over the last three months were used to allocate participants into LBP (≥30 points) or CTRL (≤10 points). Test-retest reproducibility between measurements was determined by a compilation of measures of reliability. Differences in muscular activities between LBP and CTRL were analysed descriptively for individual muscles; differences based on grouped muscles were statistically tested by using a multivariate analysis of variance (MANOVA, α =0.05).
Results: Thirteen individuals were included into the analysis of study 1. EMG latencies revealed reflex muscle activities following the perturbation (mean: 89 ms). Respective EMG amplitudes were on average 5-fold of those assessed in unperturbed strides, though being characterized by a high inter-subject variability. Test-retest reliability of muscle latencies showed a high reproducibility, both for muscles at the trunk and legs. In contrast, reproducibility of amplitudes was only weak to moderate for individual muscles, but increased when being assessed as a location specific outcome summary of grouped muscles. Seventy-six individuals were eligible for data analysis in study 2. Group allocation according to CPIS resulted in n=25 for LBP and n=29 for CTRL. Descriptive analysis of activity onsets revealed longer delays for all muscles within LBP compared to CTRL (trunk muscles: mean 10 ms; leg muscles: mean 3 ms). Onset latencies of grouped muscles revealed statistically significant differences between LBP and CTRL for right (p=0.009) and left (p=0.007) abdominal muscle groups. EMG amplitude analysis showed a high variability in activation levels between individuals, independent of group assignment or location. Statistical testing of grouped muscles indicated no significant difference in amplitudes between LBP and CTRL.
Discussion: The present research project could show that perturbed treadmill walking is suitable to provoke comprehensive reflex responses at the trunk and lower extremities, both in terms of sudden onsets and amplitudes of reflex activity. Moreover, it could demonstrate that sudden loadings under dynamic conditions provoke an altered reflex timing of muscles surrounding the trunk in people with LBP compared to CTRL. In line with previous investigations, compensation strategies seemed to be deployed in a task specific manner, with differences between LBP and CTRL being evident predominately at ventral sides. No muscular alterations exceeding the trunk could be found when being assessed under the automated task of locomotion. While rehabilitation programs tailored towards LBP are still under debate, it is tempting to urge the implementation of dynamic sudden loading incidents of the trunk to enhance motor control and thereby to improve spinal protection. Moreover, in respect to the consistently observed task specificity of muscular compensation strategies, such a rehabilitation program should be rich in variety.
Prevalence of Achilles tendinopathy increases with age, leading to a weaker tendon with predisposition to rupture. Previous studies, investigating Achilles tendon (AT) properties, are restricted to standardized isometric conditions. Knowledge regarding the influence of age and pa-thology on AT response under functional tasks remains limited. Therefore, the aim of the thesis was to investigate the influence of age and pathology on AT properties during a single-leg vertical jump.
Healthy children, asymptomatic adults and patients with Achilles tendinopathy participated. Ultrasonography was used to assess AT-length, AT-cross-sectional area and AT-elongation. The reliability of the methodology used was evaluated both Intra- and inter-rater at rest and at maximal isometric plantar-flexion contraction and was further implemented to investigate tendon properties during functional task. During the functional task a single-leg vertical jump on a force plate was performed while simultaneously AT elongation and vertical ground reaction forces were recorded. AT compliance [mm/N] (elongation/force) and AT strain [%] (elongation/length) were calculated. Differences between groups were evaluated with respect to age (children vs. adults) and pathology (asymptomatic adults vs. patients).
Good to excellent reliability with low levels of variability was achieved in the assessment of AT properties. During the jumps AT elongation was found to be statistical significant higher in children. However, no statistical significant difference was found for force among the groups. AT compliance and strain were found to be statistical significant higher only in children. No significant differences were found between asymptomatic adults and patients with tendinopathy.
The methodology used to assess AT properties is reliable, allowing its implementation into further investigations. Higher AT-compliance in children might be considered as a protective factor against load-related injuries. During functional task, when higher forces are acting on the AT, tendinopathy does not result in a weaker tendon.
Diese Arbeit ist im Bereich des Qualitätsmanagements (QM) in öffentlichen Organisationen zu verorten. Sie fragt konkret, welche Faktoren eine effektive Implementierung des QM-Systems Common Assessment Framework (CAF) in Deutschen Bundesbehörden beeinflussen. Auf der Basis des soziologischen Neo-Institutionalismus wurden Hypothesen zu möglichen Einflussfaktoren aufgestellt. Im Rahmen einer systematischen Fallauswahl wurden folgende Organisationen untersucht: das Bundeskartellamt, das Bundeszentralamt für Steuern sowie die Staatsbibliothek zu Berlin. Für den empirischen Teil dieser Arbeit wurden halbstrukturierte Leitfadeninterviews mit Experten der ausgewählten Organisationen geführt. Im Rahmen einer qualitativen Inhaltsanalyse wurden diese dann ausgewertet und mit einer „cross case synthesis“ nach Yin (2014) anschließend theoriegeleitet analysiert.
Es lassen sich letztendlich drei entscheidende Bedingungen für eine effektive CAF-Implementierung in Bundesbehörden ableiten: Zum einen die formale Unterstützung der jeweiligen Hausleitung, die eine aktive Rolle innerhalb des CAF-Projektes einnimmt und dabei auch alle mittleren Führungsspitzen zielführend mit einbinden sollte, beispielsweise durch die Übernahme der QM-Projektleitung. Zum anderen ist es für eine zielkohärente Handlungsweise aller Organisationsmitgliedern vonnöten, die verschiedenen Steuerungsinstrumente im Rahmen einer mittelfristigen Gesamtstrategie miteinander zu verzahnen und so formal zu institutionalisieren. Außerdem ist die formale Institutionalisierung einer QM-Einheit, nahe der Hausleitung außerhalb der Fachabteilungen angesiedelt, zu empfehlen. Es hat sich im Rahmen der untersuchten Fallbeispiele gezeigt, dass diese Einheiten ein größeres Potential aufweisen, sich zu QM- und CAF-Kompetenzzentren zu entwickeln und unnötige Arbeiten, die das CAF-Engagement der Mitarbeiterschaft schmälern würden, von eben jener fernzuhalten.
Durch diese Ergebnisse konnte die Arbeit zwei entscheidende Beiträge leisten: Die Forschungslandkarte der QM- und CAF-Forschung in öffentlichen Organisationen wies, speziell auf Bundesebene, vorab verschiedenste weiße Flecken auf, die von dieser Arbeit teilweise gefüllt werden konnten. Zum anderen ist es auf Basis dieser Forschungsarbeit nun möglich, Verwaltungspraktikern konkrete Handlungsempfehlungen an die Hand zu geben, wenn diese erstmals CAF in ihrer Organisation implementieren möchten oder bei einer schon erfolgten Einführung des QM-Instruments nachsteuern möchten.
Difficulties with object relative clauses (ORC), as compared to subject relative clauses (SR), are widely attested across different languages, both in adults and in children. This SR-ORC asymmetry is reduced, or even eliminated, when the embedded constituent in the ORC is a pronoun, rather than a lexical noun phrase. The studies included in this thesis were designed to explore under what circumstances the pronoun facilitation occurs; whether all pronouns have the same effect; whether SRs are also affected by embedded pronouns; whether children perform like adults on such structures; and whether performance is related to cognitive abilities such as memory or grammatical knowledge. Several theoretical approaches that explain the pronoun facilitation in relative clauses are evaluated. The experimental data have been collected in three languages–German, Italian and Hebrew–stemming from both children and adults.
In the German study (Chapter 2), ORCs with embedded 1st- or 3rd-person pronouns are compared to ORCs with an embedded lexical noun phrase. Eye-movement data from 5-year-old children show that the 1st-person pronoun facilitates processing, but not the 3rd-person pronoun. Moreover, children’s performance is modulated by additive effects of their memory and grammatical skills. In the Italian study (Chapter 3), the 1st-person pronoun advantage over the 3rd-person pronoun is tested in ORCs and SRs that display a similar word order. Eye-movement data from 5-year-olds and adult controls and reading times data from adults are pitted against the outcome of a corpus analysis, showing that the 1st-/3rd-person pronoun asymmetry emerges in the two relative clause types to an equal extent. In the Hebrew study (Chapter 4), the goal is to test the effect of a special kind of pronoun–a non-referential arbitrary subject pronoun–on ORC comprehension, in the light of potential confounds in previous studies that used this pronoun. Data from a referent-identification task with 4- to 5-year-olds indicate that, when the experimental material is controlled, the non-referential pronoun does not necessarily facilitate ORC comprehension. Importantly, however, children have even more difficulties when the embedded constituent is a referential pronoun. The non-referentiality / referentiality asymmetry is emphasized by the relation between children’s performance on the experimental task and their memory skills.
Together, the data presented in this thesis indicate that sentence processing is not only driven by structural (or syntactic) factors, but also by discourse-related ones, like pronouns’ referential properties or their discourse accessibility mechanism, which is defined as the level of ease or difficulty with which referents of pronouns are identified and retrieved from the discourse model. Although independent in essence, these structural and discourse factors can in some cases interact in a way that affects sentence processing. Moreover, both types of factors appear to be strongly related to memory. The data also support the idea that, from early on, children are sensitive to the same factors that affect adults’ sentence processing, and that the processing strategies of both populations are qualitatively similar.
In sum, this thesis suggests that a comprehensive theory of human sentence processing needs to account for effects that are due to both structural and discourse-related factors, which operate as a function of memory capacity.
Quantitative thermodynamic and geochemical modeling is today applied in a variety of geological environments from the petrogenesis of igneous rocks to the oceanic realm. Thermodynamic calculations are used, for example, to get better insight into lithosphere dynamics, to constrain melting processes in crust and mantle as well as to study fluid-rock interaction. The development of thermodynamic databases and computer programs to calculate equilibrium phase diagrams have greatly advanced our ability to model geodynamic processes from subduction to orogenesis. However, a well-known problem is that despite its broad application the use and interpretation of thermodynamic models applied to natural rocks is far from straightforward. For example, chemical disequilibrium and/or unknown rock properties, such as fluid activities, complicate the application of equilibrium thermodynamics.
One major aspect of the publications presented in this Habilitationsschrift are new approaches to unravel dynamic and chemical histories of rocks that include applications to chemically open system behaviour. This approach is especially important in rocks that are affected by element fractionation due to fractional crystallisation and fluid loss during dehydration reactions. Furthermore, chemically open system behaviour has also to be considered for studying fluid-rock interaction processes and for extracting information from compositionally zoned metamorphic minerals. In this Habilitationsschrift several publications are presented where I incorporate such open system behaviour in the forward models by incrementing the calculations and considering changing reacting rock compositions during metamorphism. I apply thermodynamic forward modelling incorporating the effects of element fractionation in a variety of geodynamic and geochemical applications in order to better understand lithosphere dynamics and mass transfer in solid rocks.
In three of the presented publications I combine thermodynamic forward models with trace element calculations in order to enlarge the application of geochemical numerical forward modeling. In these publications a combination of thermodynamic and trace element forward modeling is used to study and quantify processes in metamorphic petrology at spatial scales from µm to km. In the thermodynamic forward models I utilize Gibbs energy minimization to quantify mineralogical changes along a reaction path of a chemically open fluid/rock system. These results are combined with mass balanced trace element calculations to determine the trace element distribution between rock and melt/fluid during the metamorphic evolution. Thus, effects of mineral reactions, fluid-rock interaction and element transport in metamorphic rocks on the trace element and isotopic composition of minerals, rocks and percolating fluids or melts can be predicted.
One of the included publications shows that trace element growth zonations in metamorphic garnet porphyroblasts can be used to get crucial information about the reaction path of the investigated sample. In order to interpret the major and trace element distribution and zoning patterns in terms of the reaction history of the samples, we combined thermodynamic forward models with mass-balance rare earth element calculations. Such combined thermodynamic and mass-balance calculations of the rare earth element distribution among the modelled stable phases yielded characteristic zonation patterns in garnet that closely resemble those in the natural samples. We can show in that paper that garnet growth and trace element incorporation occurred in near thermodynamic equilibrium with matrix phases during subduction and that the rare earth element patterns in garnet exhibit distinct enrichment zones that fingerprint the minerals involved in the garnet-forming reactions.
In two of the presented publications I illustrate the capacities of combined thermodynamic-geochemical modeling based on examples relevant to mass transfer in subduction zones. The first example focuses on fluid-rock interaction in and around a blueschist-facies shear zone in felsic gneisses, where fluid-induced mineral reactions and their effects on boron (B) concentrations and isotopic compositions in white mica are modeled. In the second example, fluid release from a subducted slab and associated transport of B and variations in B concentrations and isotopic compositions in liberated fluids and residual rocks are modeled. I show that, combined with experimental data on elemental partitioning and isotopic fractionation, thermodynamic forward modeling unfolds enormous capacities that are far from exhausted.
In my publications presented in this Habilitationsschrift I compare the modeled results to geochemical data of natural minerals and rocks and demonstrate that the combination of thermodynamic and geochemical models enables quantification of metamorphic processes and insights into element cycling that would have been unattainable so far.
Thus, the contributions to the science community presented in this Habilitatonsschrift concern the fields of petrology, geochemistry, geochronology but also ore geology that all use thermodynamic and geochemical models to solve various problems related to geo-materials.
Intracontinental deformation usually is a result of tectonic forces associated with distant plate collisions. In general, the evolution of mountain ranges and basins in this environment is strongly controlled by the distribution and geometries of preexisting structures. Thus, predictive models usually fail in forecasting the deformation evolution in these kinds of settings. Detailed information on each range and basin-fill is vital to comprehend the evolution of intracontinental mountain belts and basins. In this dissertation, I have investigated the complex Cenozoic tectonic evolution of the western Tien Shan in Central Asia, which is one of the most active intracontinental ranges in the world. The work presented here combines a broad array of datasets, including thermo- and geochronology, paleoenvironmental interpretations, sediment provenance and subsurface interpretations in order to track changes in tectonic deformation. Most of the identified changes are connected and can be related to regional-scale processes that governed the evolution of the western Tien Shan.
The NW-SE trending Talas-Fergana fault (TFF) separates the western from the central Tien Shan and constitutes a world-class example of the influence of preexisting anisotropies on the subsequent structural development of a contractile orogen. While to the east most of ranges and basins have a sub-parallel E-W trend, the triangular-shaped Fergana basin forms a substantial feature in the western Tien Shan morphology with ranges on all three sides. In this thesis, I present 55 new thermochronologic ages (apatite fission track and zircon (U-Th)/He)) used to constrain exhumation histories of several mountain ranges in the western Tien Shan. At the same time, I analyzed the Fergana basin-fill looking for progressive changes in sedimentary paleoenvironments, source areas and stratal geometrical configurations in the subsurface and outcrops.
The data presented in this thesis suggests that low cooling rates (<1°C Myr-1), calm depositional environments, and low depositional rates (<10 m Myr-1) were widely distributed across the western Tien Shan, describing a quiescent tectonic period throughout the Paleogene. Increased cooling rates in the late Cenozoic occurred diachronously and with variable magnitudes in different ranges. This rapid cooling stage is interpreted to represent increased erosion caused by active deformation and constrains the onset of Cenozoic deformation in the western Tien Shan. Time-temperature histories derived from the northwestern Tien Shan samples show an increase in cooling rates by ~25 Ma. This event is correlated with a synchronous pulse
iv
in the South Tien Shan. I suggest that strike-slip motion along the TFF commenced at the Oligo-Miocene boundary, facilitating CCW rotation of the Fergana basin and enabling exhumation of the linked horsetail splays. Higher depositional rates (~150 m Myr-1) in the Oligo-Miocene section (Massaget Fm.) of the Fergana basin suggest synchronous deformation in the surrounding ranges. The central Alai Range also experienced rapid cooling around this time, suggesting that the onset of intramontane basin fragmentation and isolation is coeval. These results point to deformation starting simultaneously in the late Oligocene – early Miocene in geographically distant mountain ranges. I suggest that these early uplifts are controlled by reactivated structures (like the TFF), which are probably the frictionally weakest and most-suitably oriented for accommodating and transferring N-S horizontal shortening along the western Tien Shan.
Afterwards, in the late Miocene (~10 Ma), a period of renewed rapid cooling affected the Tien Shan and most mountain ranges and inherited structures started to actively deform. This episode is widely distributed and an increase in exhumation is interpreted in most of the sampled ranges. Moreover, the Pliocene section in the basin subsurface shows the higher depositional rates (>180 m Myr-1) and higher energy facies. The deformation and exhumation increase further contributed to intramontane basin partitioning. Overall, the interpretation is that the Tien Shan and much of Central Asia suffered a global increase in the rate of horizontal crustal shortening. Previously, stress transfer along the rigid Tarim block or Pamir indentation has been proposed to account for Himalayan hinterland deformation. However, the extent of the episode requires a different and broader geodynamic driver.
Kritische Anthropologie?
(2016)
This article compares Max Horkheimer’s and Theodor W. Adorno’s foundation of the Frankfurt Critical Theory with Helmuth Plessner’s foundation of Philosophical Anthropology. While Horkheimer’s and Plessner’s paradigms are mutually incompatible, Adorno’s „negative dialectics“ and Plessner’s „negative anthropology“ (G. Gamm) can be seen as complementing one another. Jürgen Habermas at one point sketched a complementary relationship between his own publicly communicative theory of modern society and Plessner’s philosophy of nature and human expressivity, and though he then came to doubt this, he later reaffirmed it. Faced with the „life power“ in „high capitalism“ (Plessner), the ambitions for a public democracy in a pluralistic society have to be broadened from an argumentative focus (Habermas) to include the human condition and the expressive modes of our experience as essentially embodied persons. The article discusses some possible aspects of this complementarity under the title of a „critical anthropology“ (H. Schnädelbach)
This article is a response to calls in prior research that we need more longitudi-nal analyses to better understand the foundations of PSM and related prosocial values. There is wide agreement that it is crucial for theory-building but also for tailoring hiring practices and human resource development programs to sort out whether PSM-related values are stable or developable. The article summarizes existent theoretical expecta-tions, which turn out to be partially conflicting, and tests them against multiple waves of data from the German Socio-Economic Panel Study which covers a time period of sixteen years. It finds that PSM-related values of public employees are stable rather than dynamic but tend to increase with age and decrease with organizational member-ship. The article also examines cohort effects, which have been neglected in prior work, and finds moderate evidence that there are differences between those born during the Second World War and later generations.
Precision horticulture encompasses site- or tree-specific management in fruit plantations. Of decisive importance is spatially resolved data (this means data from each tree) from the production site, since it may enable customized and, therefore, resource-efficient production measures.
The present thesis involves an examination of the apparent electrical conductivity of the soil (ECa), the plant water status spatially measured by means of the crop water stress index (CWSI), and the fruit quality (e.g. fruit size) for Prunus domestica L. (plums) and Citrus x aurantium, Syn. Citrus paradisi (grapefruit). The goals of the present work were i) characterization of the 3D distribution of the apparent electrical conductivity of the soil and variability of the plant’s water status; ii) investigation of the interaction between ECa, CWSI, and fruit quality; and iii) an approach for delineating management zones with respect to managing trees individually.
To that end, the main investigations took place in the plum orchard. This plantation got a slope of 3° grade on Pleistocene and post-Pleistocene substrates in a semi-humid climate (Potsdam, Germany) and encloses an area of 0.37 ha with 156 trees of the cultivar ˈTophit Plusˈ on a Wavit rootstock. The plantation was laid in 2009 with annual and biannual trees spaced 4 m distance along the irrigation system and 5 m between the rows. The trees were watered three times a week with a drip irrigation system positioned 50 cm above ground level providing 1.6 l per tree per event. With the help of geoelectric measurements, the apparent electrical conductivity of the upper soil (0.25 m) was measured for each tree with an electrode spacing of 0.5 m (4-point light hp). In this manner, the plantation was spatially charted with respect to the soil’s ECa. Additionally, tomography measurements were performed for 3D mapping of the soil ECa and spot checks of drilled cores with a profile of up to 1 m. The vegetative, generative, and fruit quality data were collected for each tree. The instantaneous plant water status was comprehensively determined in spot checks with the established Scholander method for water potential analysis (Scholander pressure bomb) as well as thermal imaging. An infrared camera was used for the thermal imaging (ThermaCam SC 500), mounted on a tractor 3.3 m above ground level. The thermal images (320 x 240 px) of the canopy surface were taken with an aperture of 45° and a geometric resolution of 8.54 x 6.41 mm. With the aid of the canopy temperature readings from the thermal images, cross-checked with manual temperature measurements of a dry and a wet reference leaf, the crop water stress index (CWSI) was calculated. Adjustments in CWSI for measurements in a semi-humid climate were developed, whereas the collection of reference temperatures was automatically collected from thermal images.
The bonitur data were transformed with the help of a variance stabilization process into a normal distribution. The statistical analyses as well as the automatic evaluation routine were performed with several scripts in MATLAB® (R2010b and R2016a) and a free program (spatialtoolbox). The hot spot analysis served to check whether an observed pattern is statistically significant. The method was evaluated with an established k-mean analysis. To test the hot-spot analysis by comparison, data from a grapefruit plantation (Adana, Turkey) was collected, including soil ECa, trunk circumference, and yield data. The plantation had 179 trees on a soil of type Xerofkuvent with clay and clay-loamy texture. The examination of the interaction between the critical values from the soil and plant water status information and the vegetative and generative plant growth variables was performed with the application from ANOVA.
The study indicates that the variability of the soil and plant information in fruit production is high, even considering small orchards. It was further indicated that the spatial patterns found in the soil ECa stayed constant through the years (r = 0.88 in 2011-2012 and r = 0.71 in 2012-2013). It was also demonstrated that CWSI determination may also be possible in semi-humid climate. A correlation (r = - 0.65, p < 0.0001) with the established method of leaf water potential analysis was found. The interaction between the ECa from various depths and the plant variables produced a highly significant connection with the topsoil in which the irrigation system was to be found. A correlation between yield and ECatopsoil of r = 0.52 was determined. By using the hot-spot analysis, extreme values in the spatial data could be determined. These extremes served to divide the zones (cold-spot, random, hot-spot). The random zone showed the highest correlation to the plant variables.
In summary it may be said that the cumulative water use efficiency (WUEc) was enhanced with high crop load. While the CWSI had no effect on fruit quality, the interaction of CWSI and WUEc even outweighed the impact of soil ECa on fruit quality in the production system with irrigation. In the plum orchard, irrigation was relevant for obtaining high quality produce even in the semi-humid climate.
Kommunikative Vernunft
(2016)
Jürgen Habermas explicates the concept of communicative reason. He explains the key assumptions of the philosophy of language and social theory associated with this concept. Also discussed is the category of life-world and the role of the body-mind difference for the consciousness of exclusivity in our access to subjective experience. as well as the role of emotions and perceptions in the context of a theory of communicative action. The question of the redemption of the various validity claims as they are associated with the performance of speech acts is related to processes of social learning and to the role of negative experiences. Finally the interview deals with the relationship between religion and reason and the importance of religion in modern, post-secular societies. Questions about the philosophical culture of our present times are discussed at the end of the conversation.
This article explores a recent performance of excerpts from T.S. Eliot’s Four Quartets (1935/36–1942) entitled Engaging Eliot: Four Quartets in Word, Color, and Sound as an example of live poetry. In this context, Eliot’s poem can be analysed as an auditory artefact that interacts strongly with other oral performances (welcome addresses and artists’ conversations), as well as with the musical performance of Christopher Theofanidis’s quintet “At the Still Point” at the end of the opening of Engaging Eliot. The event served as an introduction to a 13-day art exhibition and engaged in a re-evaluation of Eliot’s poem after 9/11: while its first part emphasises the connection between Eliot’s poem and Christian doctrine, its second part – especially the combination of poetry reading and musical performance – highlights the philosophical and spiritual dimensions of Four Quartets.
This article first outlines different ways of how psycholinguists have dealt with linguistic diversity and illustrates these approaches with three familiar cases from research on language processing, language acquisition, and language disorders. The second part focuses on the role of morphology and morphological variability across languages for psycholinguistic research. The specific phenomena to be examined are to do with stem-formation morphology and inflectional classes; they illustrate how experimental research that is informed by linguistic typology can lead to new insights.
The present study approaches the Spanish postposed constructions creo Ø and creo yo ‘[p], [I] think’ from a cognitive-constructionist perspective. It is argued that both constructions are to be distinguished from one another because creo Ø has a subjective function, while in creo yo, it is the intersubjective dimension that is particularly prominent. The present investigation takes both a qualitative and a quantitative perspective. With regard to the latter, the problem of quantitative representativity is addressed. The discussion posed the question of how empirical research can feed back into theory, more precisely, into the framework of Cognitive Construction Grammar. The data to be analyzed here are retrieved from the corpora Corpus de Referencia del Español Actual and Corpus del Español.
Complex networks are ubiquitous in nature and society. They appear in vastly different domains, for instance as social networks, biological interactions or communication networks. Yet in spite of their different origins, these networks share many structural characteristics. For instance, their degree distribution typically follows a power law. This means that the fraction of vertices of degree k is proportional to k^(−β) for some constant β; making these networks highly inhomogeneous. Furthermore, they also typically have high clustering, meaning that links between two nodes are more likely to appear if they have a neighbor in common.
To mathematically study the behavior of such networks, they are often modeled as random graphs. Many of the popular models like inhomogeneous random graphs or Preferential Attachment excel at producing a power law degree distribution. Clustering, on the other hand, is in these models either not present or artificially enforced.
Hyperbolic random graphs bridge this gap by assuming an underlying geometry to the graph: Each vertex is assigned coordinates in the hyperbolic plane, and two vertices are connected if they are nearby. Clustering then emerges as a natural consequence: Two nodes joined by an edge are close by and therefore have many neighbors in common. On the other hand, the exponential expansion of space in the hyperbolic plane naturally produces a power law degree sequence. Due to the hyperbolic geometry, however, rigorous mathematical treatment of this model can quickly become mathematically challenging.
In this thesis, we improve upon the understanding of hyperbolic random graphs by studying its structural and algorithmical properties. Our main contribution is threefold. First, we analyze the emergence of cliques in this model. We find that whenever the power law exponent β is 2 < β < 3, there exists a clique of polynomial size in n. On the other hand, for β >= 3, the size of the largest clique is logarithmic; which severely contrasts previous models with a constant size clique in this case. We also provide efficient algorithms for finding cliques if the hyperbolic node coordinates are known. Second, we analyze the diameter, i. e., the longest shortest path in the graph. We find
that it is of order O(polylog(n)) if 2 < β < 3 and O(logn) if β > 3. To complement
these findings, we also show that the diameter is of order at least Ω(logn). Third, we provide an algorithm for embedding a real-world graph into the hyperbolic plane using only its graph structure. To ensure good quality of the embedding, we perform extensive computational experiments on generated hyperbolic random graphs. Further, as a proof of concept, we embed the Amazon product recommendation network and observe that products from the same category are mapped close together.
During the last decade, high intensity interval training (HIIT) has been used as an alternative to endurance (END) exercise, since it requires less time to produce similar physiological adaptations. Previous literature has focused on HIIT changes in aerobic metabolism and cardiorespiratory fitness, however, there are currently no studies focusing on its neuromuscular adaptations.
Therefore, this thesis aimed to compare the neuromuscular adaptations of both HIIT and END after a two-week training intervention, by using a novel technology called high-density surface electromyography (HDEMG) motor unit decomposition. This project consisted in two experiments, where healthy young men were recruited (aged between 18 to 35 years). In experiment one, the reliability of HDEMG motor unit variables (mean discharge rate, peak-to-peak amplitude, conduction velocity and discharge rate variability) was tested (Study 1), a new method to track the same motor units longitudinally was proposed (Study 2), and the level of low (<5Hz) and high (>5Hz) frequency motor unit coherence between vastus medialis (VM) and lateralis (VL) knee extensor muscles was measured (Study 4). In experiment two, a two-week HIIT and END intervention was conducted where cardiorespiratory fitness parameters (e.g. peak oxygen uptake) and motor unit variables from the VM and VL muscles were assessed pre and post intervention (Study 3).
The results showed that HDEMG is reliable to monitor changes in motor unit activity and also allows the tracking of the same motor units across different testing sessions. As expected, both HIIT and END improved cardiorespiratory fitness parameters similarly. However, the neuromuscular adaptations of both types of training differed after the intervention, with HIIT showing a significant increase in knee extensor muscle strength that was accompanied by increased VM and VL motor unit discharge rates and HDEMG amplitude at the highest force levels [(50 and 70% of the maximum voluntary contraction force (MVC)], while END training induced a marked increase in time to task failure at lower force levels (30% MVC), without any influence on HDEMG amplitude and discharge rates. Additionally, the results showed that VM and VL muscles share most of their synaptic input since they present a large amount of low and high frequency motor unit coherence, which can explain the findings of the training intervention where both muscles showed similar changes in HDEMG amplitude and discharge rates.
Taken together, the findings of the current thesis show that despite similar improvements in cardiopulmonary fitness, HIIT and END induced opposite adjustments in motor unit behavior. These results suggest that HIIT and END show specific neuromuscular adaptations, possibly related to their differences in exercise load intensity and training volume.
This work reports about new high-resolution imaging and spectroscopic observations of solar type III radio bursts at low radio frequencies in the range from 30 to 80 MHz. Solar type III radio bursts are understood as result of the beam-plasma interaction of electron beams in the corona. The Sun provides a unique opportunity to study these plasma processes of an active star. Its activity appears in eruptive events like flares, coronal mass ejections and radio bursts which are all accompanied by enhanced radio emission. Therefore solar radio emission carries important information about plasma processes associated with the Sun’s activity. Moreover, the Sun’s atmosphere is a unique plasma laboratory with plasma processes under conditions not found in terrestrial laboratories. Because of the Sun’s proximity to Earth, it can be studied in greater detail than any other star but new knowledge about the Sun can be transfer to them. This “solar stellar connection” is important for the understanding of processes on other stars.
The novel radio interferometer LOFAR provides imaging and spectroscopic capabilities to study these processes at low frequencies. Here it was used for solar observations.
LOFAR, the characteristics of its solar data and the processing and analysis of the latter with the Solar Imaging Pipeline and Solar Data Center are described. The Solar Imaging Pipeline is the central software that allows using LOFAR for solar observations. So its development was necessary for the analysis of solar LOFAR data and realized here. Moreover a new density model with heat conduction and Alfvén waves was developed that provides the distance of radio bursts to the Sun from dynamic radio spectra.
Its application to the dynamic spectrum of a type III burst observed on March 16, 2016 by LOFAR shows a nonuniform radial propagation velocity of the radio emission. The analysis of an imaging observation of type III bursts on June 23, 2012 resolves a burst as bright, compact region localized in the corona propagating in radial direction along magnetic field lines with an average velocity of 0.23c. A nonuniform propagation velocity is revealed. A new beam model is presented that explains the nonuniform motion of the radio source as a propagation effect of an electron ensemble with a spread velocity distribution and rules out a monoenergetic electron distribution. The coronal electron number density is derived in the region from 1.5 to 2.5 R☉ and fitted with the newly developed density model. It determines the plasma density for the interplanetary space between Sun and Earth. The values correspond to a 1.25- and 5-fold Newkirk model for harmonic and fundamental emission, respectively. In comparison to data from other radio instruments the LOFAR data shows a high sensitivity and resolution in space, time and frequency.
The new results from LOFAR’s high resolution imaging spectroscopy are consistent with current theories of solar type III radio bursts and demonstrate its capability to track fast moving radio sources in the corona. LOFAR solar data is found to be a valuable source for solar radio physics and opens a new window for studying plasma processes associated with highly energetic electrons in the solar corona.
Proteins are natural polypeptides produced by cells; they can be found in both animals and plants, and possess a variety of functions. One of these functions is to provide structural support to the surrounding cells and tissues. For example, collagen (which is found in skin, cartilage, tendons and bones) and keratin (which is found in hair and nails) are structural proteins. When a tissue is damaged, however, the supporting matrix formed by structural proteins cannot always spontaneously regenerate. Tailor-made synthetic polypeptides can be used to help heal and restore tissue formation.
Synthetic polypeptides are typically synthesized by the so-called ring opening polymerization (ROP) of α-amino acid N-carboxyanhydrides (NCA). Such synthetic polypeptides are generally non-sequence-controlled and thus less complex than proteins. As such, synthetic polypeptides are rarely as efficient as proteins in their ability to self-assemble and form hierarchical or structural supramolecular assemblies in water, and thus, often require rational designing. In this doctoral work, two types of amino acids, γ-benzyl-L/D-glutamate (BLG / BDG) and allylglycine (AG), were selected to synthesize a series of (co)polypeptides of different compositions and molar masses.
A new and versatile synthetic route to prepare polypeptides was developed, and its mechanism and kinetics were investigated. The polypeptide properties were thoroughly studied and new materials were developed from them. In particular, these polypeptides were able to aggregate (or self-assemble) in solution into microscopic fibres, very similar to those formed by collagen. By doing so, they formed robust physical networks and organogels which could be processed into high water-content, pH-responsive hydrogels. Particles with highly regular and chiral spiral morphologies were also obtained by emulsifying these polypeptides. Such polypeptides and the materials derived from them are, therefore, promising candidates for biomedical applications.
Extreme hydro-meteorological events, such as severe droughts or heavy rainstorms, constitute primary manifestations of climate variability and exert a critical impact on the natural environment and human society. This is particularly true for high-mountain areas, such as the eastern flank of the southern Central Andes of NW Argentina, a region impacted by deep convection processes that form the basis of extreme events, often resulting in floods, a variety of mass movements, and hillslope processes. This region is characterized by pronounced E-W gradients in topography, precipitation, and vegetation cover, spanning low to medium-elevation, humid and densely vegetated areas to high-elevation, arid and sparsely vegetated environments. This strong E-W gradient is mirrored by differences in the efficiency of surface processes, which mobilize and transport large amounts of sediment through the fluvial system, from the steep hillslopes to the intermontane basins and further to the foreland. In a highly sensitive high-mountain environment like this, even small changes in the spatiotemporal distribution, magnitude and rates of extreme events may strongly impact environmental conditions, anthropogenic activity, and the well-being of mountain communities and beyond. However, although the NW Argentine Andes comprise the catchments for the La Plata river that traverses one of the most populated and economically relevant areas of South America, there are only few detailed investigations of climate variability and extreme hydro-meteorological events.
In this thesis, I focus on deciphering the spatiotemporal variability of rainfall and river discharge, with particular emphasis on extreme hydro-meteorological events in the subtropical southern Central Andes of NW Argentina during the past seven decades. I employ various methods to assess and quantify statistically significant trend patterns of rainfall and river discharge, integrating high-quality daily time series from gauging stations (40 rainfall and 8 river discharge stations) with gridded datasets (CPC-uni and TRMM 3B42 V7), for the period between 1940 and 2015. Evidence for a general intensification of the hydrological cycle at intermediate elevations (~ 0.5 – 3 km asl) at the eastern flank of the southern Central Andes is found both from rainfall and river-discharge time-series analysis during the period from 1940 to 2015. This intensification is associated with the increase of the annual total amount of rainfall and the mean annual discharge. However, most pronounced trends are found at high percentiles, i.e. extreme hydro-meteorological events, particularly during the wet season from December to February.An important outcome of my studies is the recognition of a rapid increase in the amount of river discharge during the period between 1971 and 1977, most likely linked to the 1976-77 global climate shift, which is associated with the North Pacific Ocean sea surface temperature variability. Interestingly, after this rapid increase, both rainfall and river discharge decreased at low and intermediate elevations along the eastern flank of the Andes. In contrast, during the same time interval, at high elevations, extensive areas on the arid Puna de Atacama plateau have recorded increasing annual rainfall totals. This has been associated with more intense extreme hydro-meteorological events from 1979 to 2014. This part of the study reveals that low-, intermediate, and high-elevation sectors in the Andes of NW Argentina respond differently to changing climate conditions.
Possible forcing mechanisms of the pronounced hydro-meteorological variability observed in the study area are also investigated. For the period between 1940 and 2015, I analyzed modes of oscillation of river discharge from small to medium drainage basins (102 to 104 km2), located on the eastern flank of the orogen. First, I decomposed the relevant monthly time series using the Hilbert-Huang Transform, which is particularly appropriate for non-stationary time series that result from non-linear natural processes. I observed that in the study region discharge variability can be described by five quasi-periodic oscillatory modes on timescales varying from 1 to ~20 years. Secondly, I tested the link between river-discharge variations and large-scale climate modes of variability, using different climate indices, such as the BEST ENSO (Bivariate El Niño-Southern Oscillation Time-series) index. This analysis reveals that, although most of the variance on the annual timescale is associated with the South American Monsoon System, a relatively large part of river-discharge variability is linked to Pacific Ocean variability (PDO phases) at multi-decadal timescales (~20 years). To a lesser degree, river discharge variability is also linked to the Tropical South Atlantic (TSA) sea surface temperature anomaly at multi-annual timescales (~2-5 years).
Taken together, these findings exemplify the high degree of sensitivity of high-mountain environments with respect to climatic variability and change. This is particularly true for the topographic transitions between the humid, low-moderate elevations and the semi-arid to arid highlands of the southern Central Andes. Even subtle changes in the hydro-meteorological regime of these areas of the mountain belt react with major impacts on erosional hillslope processes and generate mass movements that fundamentally impact the transport capacity of mountain streams. Despite more severe storms in these areas, the fluvial system is characterized by pronounced variability of the stream power on different timescales, leading to cycles of sediment aggradation, the loss of agriculturally used land and severe impacts on infrastructure.
Solar-like stars maintain their magnetic fields thanks to a dynamo mechanism. The Babcock-Leighton dynamo is one possible dynamo that has the particularity to require magnetic flux tubes. Magnetic flux tubes are assumed to form at the bottom of the convective zone and rise buoyantly to the surface. A delayed dynamo model has been suggested, where the delay accounts for the rise time of the magnetic flux tubes; a time, that has been ignored by former studies.
The present thesis aims to study the applicability of the flux tube/Babcock-Leighton dynamo to other stars. To do so, we attempt to constrain the rise time of magnetic flux tubes thanks to the first fully compressible MHD simulations of rising magnetic flux tubes in stratified rotating spherical shells.
Such simulations are limited to an unrealistic parameter space, therefore, a scaling relation is required to scale the results to realistic physical regimes. We extended earlier works on 2D scaling relations and derived a general scaling law valid for both 2D and 3D. We then carried out two large series of numerical experiments and verified that the scaling law we have derived indeed applies to the fully non-linear case. It allowed us to extract a constraint for the rise time of magnetic flux tubes that is valid for any solar-like star. We finally introduced this constraint to a delayed dynamo model.
By carrying out simulations of a mean-field, delayed, flux tube/Babcock-Leighton dynamo, we were able to identify a new dynamo regime resulting from the delay. This regime requires delays about an entire cycle and exhibits subequipartition magnetic activity. Revealing this new regime shows that even for long delays the flux tube/Babcock-Leighton dynamo can still deliver non-decaying solutions and remains a good candidate for a wide range of solar-like stars.
Diese Arbeit befasst sich mit der Herstellung und Charakterisierung von thermoresponsiven Filmen auf Goldelektroden durch Fixierung eines bereits synthetisierten thermoresponsiven Polymers. Als Basis für die Entwicklung der responsiven Grenzfläche dienten drei unterschiedliche Copolymere (Polymere I, II und III) aus der Gruppe der thermisch schaltbaren Poly(oligo(ethylenglykol)methacrylate).
Die turbidimetrischen Messungen der Copolymere in Lösungen haben gezeigt, dass der Trübungspunkt vom pH-Wert, der Gegenwart von Salzen sowie von der Ionenstärke der Lösung abhängig ist. Nach der Charakterisierung der Polymere in Lösung wurden Experimente der kovalenten Kopplung der Polymere I bis III an die Oberfläche der Gold-Elektroden durchgeführt. Während bei Polymeren I und II die Ankopplung auf einer Amidverbrückung basierte, wurde bei Polymer III als alternative Methode zur Immobilisierung eine photoinduzierte Anbindung unter gleichzeitiger Vernetzung gewählt. Der Nachweis der erfolgreichen Ankopplung erfolgte bei allen Polymeren elektrochemisch mittels Cyclovoltammetrie und Impedanzspektroskopie in K3/4[Fe(CN)6]-Lösungen. Wie die Ellipsometrie-Messungen zeigten, waren die erhaltenen Polymer-Filme unterschiedlich dick. Die Ankopplung über Amidverbrückung lieferte dünne Filme (10 – 15 nm), während der photovernetzte Film deutlich dicker war (70-80 nm) und die darunter liegende Oberfläche relativ gut isolierte.
Elektrochemische Temperaturexperimente an Polymer-modifizierten Oberflächen in Lösungen in Gegenwart von K3/4[Fe(CN)6] zeigten, dass auch die immobilisierten Polymere I bis III responsives Temperaturverhalten zeigen. Bei Elektroden mit den immobilisierten Polymeren I und II ist der Temperaturverlauf der Parameterwerte diskontinuierlich – ab einem kritischen Punkt (37 °C für Polymer I und 45 °C für Polymer II) wird zunächst langsame Zunahme der Peakströme wird deutlich schneller. Das Temperaturverhalten von Polymer III ist dagegen bis 50 °C kontinuierlich, der Peakstrom sinkt hier durchgehend.
Weiterhin wurde mit den auf Polymeren II und III basierten Elektroden deren Anwendung als responsive Matrix für Bioerkennungsreaktionen untersucht. Es wurde die Ankopplung von kleinen Biorezeptoren, TAG-Peptiden, an Polymer II- und Polymer III-modifizierten Elektroden durchgeführt. Das hydrophile FLAG-TAG-Peptid verändert das Temperaturverhalten des Polymer II-Films unwesentlich, da es die Hydrophilie des Netzwerkes nicht beeinflusst. Weiterhin wurde der Effekt der Ankopplung der ANTI-FLAG-TAG-Antikörper an FLAG-TAG-modifizierte Polymer II-Filme untersucht. Es konnte gezeigt werden, dass die Antikörper spezifisch an FLAG-TAG-modifiziertes Polymer II binden. Es wurde keine unspezifische Anbindung von ANTI-FLAG-TAG an Polymer II beobachtet. Die Temperaturexperimente haben gezeigt, dass die thermische Restrukturierung des Polymer II-FLAG-TAG-Filmes auch nach der Antikörper-Ankopplung noch stattfindet. Der Einfluss der ANTI-FLAG-TAG-Ankopplung ist gering, da der Unterschied in der Hydrophilie zwischen Polymer II und FLAG-TAG bzw. ANTI-FLAG-TAG zu gering ist.
Für die Untersuchungen mit Polymer III-Elektroden wurde neben dem hydrophilen FLAG-TAG-Peptid das deutlich hydrophobere HA-TAG-Peptid ausgewählt. Wie im Falle der Polymer II Elektrode beeinflusst das gekoppelte FLAG-TAG-Peptid das Temperaturverhalten des Polymer III-Netzwerkes nur geringfügig. Die gemessenen Stromwerte sind geringer als bei der Polymer III-Elektrode. Das Temperaturverhalten der FLAG-TAG-Elektrode ähnelt dem der reinen Polymer III-Elektrode – die Stromwerte sinken kontinuierlich bis die Temperatur von ca. 40 °C erreicht ist, bei der ein Plateau beobachtet wird. Offensichtlich verändert FLAG-TAG auch in diesem Fall nicht wesentlich die Hydrophilie des Polymer III-Netzwerkes. Das an Polymer III-Elektroden gekoppelte hydrophobe HA-TAG-Peptid beeinflusst dagegen im starken Maße den Quellzustand des Netzwerkes. Die Ströme für die HA-TAG-Elektroden sind deutlich geringer als die für die FLAG-TAG-Polymer III-Elektroden, was auf geringeren Wassergehalt und dickeren Film zurückzuführen ist. Bereits ab 30 °C erfolgt der Anstieg von Stromwerten, der bei Polymer III- bzw. bei Polymer III-FLAG-TAG-Elektroden nicht beobachtet werden kann. Das gekoppelte hydrophobe HA-TAG-Peptid verdrängt Wasser aus dem Polymer III-Netzwerk, was in der Stauchung des Films bereits bei Raumtemperatur resultiert. Dies führt dazu, dass der Film im Laufe des Temperaturanstieges kaum noch komprimiert. Die Stromwerte steigen in diesem Fall entsprechend des Anstiegs der temperaturabhängigen Diffusion des Redoxpaares. Diese Untersuchungen zeigen, dass das HA-TAG-Peptid als Ankermolekül deutlich besser für eine potentielle Verwendung der Polymer III-Filme für sensorische Zwecke geeignet ist, da es sich deutlich in der Hydrophilie von Polymer III unterscheidet.
Numerous reports of relatively rapid climate changes over the past century make a clear case of the impact of aerosols and clouds, identified as sources of largest uncertainty in climate projections. Earth’s radiation balance is altered by aerosols depending on their size, morphology and chemical composition. Competing effects in the atmosphere can be further studied by investigating the evolution of aerosol microphysical properties, which are the focus of the present work.
The aerosol size distribution, the refractive index, and the single scattering albedo are commonly used such properties linked to aerosol type, and radiative forcing. Highly advanced lidars (light detection and ranging) have reduced aerosol monitoring and optical profiling into a routine process. Lidar data have been widely used to retrieve the size distribution through the inversion of the so-called Lorenz-Mie model (LMM). This model offers a reasonable treatment for spherically approximated particles, it no longer provides, though, a viable description for other naturally occurring arbitrarily shaped particles, such as dust particles. On the other hand, non-spherical geometries as simple as spheroids reproduce certain optical properties with enhanced accuracy. Motivated by this, we adapt the LMM to accommodate the spheroid-particle approximation introducing the notion of a two-dimensional (2D) shape-size distribution.
Inverting only a few optical data points to retrieve the shape-size distribution is classified as a non-linear ill-posed problem. A brief mathematical analysis is presented which reveals the inherent tendency towards highly oscillatory solutions, explores the available options for a generalized solution through regularization methods and quantifies the ill-posedness. The latter will improve our understanding on the main cause fomenting instability in the produced solution spaces. The new approach facilitates the exploitation of additional lidar data points from depolarization measurements, associated with particle non-sphericity. However, the generalization of LMM vastly increases the complexity of the problem. The underlying theory for the calculation of the involved optical cross sections (T-matrix theory) is computationally so costly, that would limit a retrieval analysis to an unpractical point. Moreover the discretization of the model equation by a 2D collocation method, proposed in this work, involves double integrations which are further time consuming. We overcome these difficulties by using precalculated databases and a sophisticated retrieval software (SphInX: Spheroidal Inversion eXperiments) especially developed for our purposes, capable of performing multiple-dataset inversions and producing a wide range of microphysical retrieval outputs.
Hybrid regularization in conjunction with minimization processes is used as a basis for our algorithms. Synthetic data retrievals are performed simulating various atmospheric scenarios in order to test the efficiency of different regularization methods. The gap in contemporary literature in providing full sets of uncertainties in a wide variety of numerical instances is of major concern here. For this, the most appropriate methods are identified through a thorough analysis on an overall-behavior basis regarding accuracy and stability. The general trend of the initial size distributions is captured in our numerical experiments and the reconstruction quality depends on data error level. Moreover, the need for more or less depolarization points is explored for the first time from the point of view of the microphysical retrieval. Finally, our approach is tested in various measurement cases giving further insight for future algorithm improvements.
Möglichkeiten der Mittelstandsförderung durch Vergaberechtsgestaltung und Vergaberechtspraxis
(2016)
Die Förderungswürdigkeit und die Förderungsfähigkeit mittelständischer Unternehmen ist ein gesamteuropäisches, wirtschaftspolitisches Anliegen. Hiervon zeugen zum einen zahlreiche Regelungen im Primär-, Sekundär-, Verfassungs- und einfachgesetzlichem Recht, zum anderen auch die Bedeutung der mittelständischen Unternehmen im wirtschaftlichen, gesellschaftlichen und sozialen Gefüge. So herrscht innerhalb der Europäischen Union nicht nur der Slogan „Vorfahrt für KMU“, sondern auch die im Frühjahr 2014 verabschiedeten Vergaberichtlinien legten ein besonderes Augenmerk auf die Förderung des Zugangs der KMU zum öffentlichen Beschaffungsmarkt. Denn gemessen am Steuerungs- und Lenkungspotenzial der Auftragsvergabe, deren Einfluss auf die Innovationstätigkeit der Wirtschaft sowie deren Auswirkungen auf die Wirtschafts- und Wettbewerbstätigkeit auf der einen Seite und dem gesamtwirtschaftlichen Stellenwert der mittelständischen Unternehmen auf der anderen Seite, sind mittelständische Unternehmen trotz zahlreicher europäischer und nationaler Initiativen im Vergabeverfahren unterrepräsentiert. Neben der undurchsichtigen Regelungsstruktur des deutschen Vergaberechts, unterliegen die mittelständischen Unternehmen vom Beginn bis zum Ende des Vergabeverfahrens besonderen Schwierigkeiten. Dieser Ausgangsbefund wurde zum Anlass genommen, um die Möglichkeiten der Mittelstandsförderung durch Vergaberechtsgestaltung und Vergaberechtspraxis erneut auf den Prüfstand zu stellen.
Infants' lexical processing is modulated by featural manipulations made to words, suggesting that early lexical representations are sufficiently specified to establish a match with the corresponding label. However, the precise degree of detail in early words requires further investigation due to equivocal findings. We studied this question by assessing children’s sensitivity to the degree of featural manipulation (Chapters 2 and 3), and sensitivity to the featural makeup of homorganic and heterorganic consonant clusters (Chapter 4). Gradient sensitivity on the one hand and sensitivity to homorganicity on the other hand would suggest that lexical processing makes use of sub-phonemic information, which in turn would indicate that early words contain sub-phonemic detail. The studies presented in this thesis assess children’s sensitivity to sub-phonemic detail using minimally demanding online paradigms suitable for infants: single-picture pupillometry and intermodal preferential looking. Such paradigms have the potential to uncover lexical knowledge that may be masked otherwise due to cognitive limitations. The study reported in Chapter 2 obtained a differential response in pupil dilation to the degree of featural manipulation, a result consistent with gradient sensitivity. The study reported in Chapter 3 obtained a differential response in proportion of looking time and pupil dilation to the degree of featural manipulation, a result again consistent with gradient sensitivity. The study reported in Chapter 4 obtained a differential response to the manipulation of homorganic and heterorganic consonant clusters, a result consistent with sensitivity to homorganicity. These results suggest that infants' lexical representations are not only specific, but also detailed to the extent that they contain sub-phonemic information.
Das Widerspenstige bändigen
(2016)
Dem Handeln von Lehrkräften wird in der schulischen Praxis wie in der wissenschaftlichen Literatur ein wesentlicher Einfluss auf die Qualität von schulischem Unterricht zugesprochen. Auch wenn umfangreiche normative Vorstellungen über ein gutes Lehr-Handeln bestehen, so gibt es wenig Erkenntnis darüber, welche Gründe Lehrkräfte für ihr pädagogisches Handeln haben. Das Handeln von Lehrkräften kann nur dann adäquat erfasst werden, wenn Bildung einerseits als Weitergabe von Kultur an die nachfolgende Generation und andererseits als eine vom sich bildenden Subjekt ausgehende Selbst- und Weltverständigung verstanden wird. Damit einhergehende Anforderungen an die Lehrkraft stehen notwendigerweise in Widerspruch zueinander; dies gilt besonders für eine Gesellschaft mit großer kultureller und sozialer Heterogenität. Bei der Suche nach Zusammenhängen zwischen Persönlichkeit, pädagogischem Wissen oder Kompetenzen und einem unterrichtlichen Handeln wird häufig von einer Bedingtheit dieses Handelns ausgegangen und dieses auf kognitive Aspekte und an externen Normen orientierte Merkmale verkürzt. Ertragreicher für eine Antwort auf die Frage nach den Begründungen sind wissenschaftliche Arbeiten, die Professionalität als eine Bezugnahme auf einen besonderen strukturellen Rahmen beschreiben, der durch Widersprüche geprägt ist und Entscheidungen zu den Spannungsfeldern pädagogischer Verhältnisse erfordert. Die subjektwissenschaftliche Lerntheorie bietet eine Basis für ein Verständnis eines Lernens in institutionellen Kontexten ausgehend von den Lerninteressen der Schülerinnen und Schüler. Lehren kann darauf bezugnehmend als Unterstützung von Selbst- und Weltverständigungsprozessen durch Wertschätzung, Verstehen und Angebote alternativer Bedeutungshorizonte verstanden werden. Das Handeln von Lehrkräften ist als sinngebende Bezugnahme auf daraus resultierende sowie institutionelle Anforderungen mittels gesellschaftlicher Bedeutungsstrukturen verstehbar. Das handelnde Subjekt erschließt sich selbst und die Welt mit Hilfe von Bedeutungen. Diese können verstanden werden als der Besonderheit der Biographie, der gesellschaftlichen Position sowie der Lebenslage geschuldete Reinterpretationen gesellschaftlicher Bedeutungsstrukturen. Im empirischen Verfahren können mittels eines Übergangs von sequentiellen zu komparativen Analysen Positionierungen als thematisch spezifische und über die konkrete Handlungssituation hinausreichende Bedeutungs-Begründungs-Zusammenhänge rekonstruiert werden. Daraus werden situationsunabhängige Strukturmomente des Gegenstands Lehren an beruflichen Schulen aber auch komplexe, situationsbezogene subjektive Bedeutungs-Begründungs-Muster abgeleitet. Als wesentliche strukturelle Merkmale lassen sich die Schlüsselkategorien ‚Deutungsmacht‘ und ‚instrumentelle pädagogische Beziehung‘ aus dem empirischen Material unter Zuhilfenahme weiterer theoretischer Folien entwickeln. Da Deutungsmacht auf Akzeptanz angewiesen ist und in instrumentellen Beziehungen eine kooperative Bezugnahme auf den Lehr-Lern-Gegenstand allenfalls punktuell erfolgt, können damit asymmetrische metastabile Arrangements zwischen einer Lehrkraft und Schülerinnen und Schülern verstanden werden. Als empirische Ausprägungen weist Deutungsmacht die Varianten ‚absoluter Anspruch‘, ‚Akzeptanz der Fragilität‘ und ‚Akzeptanz der Legitimität eines Infragestellens‘ auf. Bei der zweiten Schlüsselkategorie treten die Varianten ‚strukturelle Prägung‘, ‚unspezifischer allgemein-menschlicher Charakter‘ und ‚Außenprägung‘ der instrumentellen pädagogischen Beziehung auf. Die Bedeutungs-Begründungs-Musters weisen teilweise Inkonsistenzen und Übergänge in den Positionierungen bezogen auf die dargestellten Varianten auf. Nur bei einem Teil der Muster sind Bemühungen um Wertschätzung und Verstehen der Schülerinnen und Schüler plausibel ableitbar, gleiches gilt in Hinblick auf eine Offenheit für eine Revision der Muster. Die Muster, wie etwa ‚Durchsetzend-ertragendes Nachsteuern‘, ‚Direktiv-personalisierendes Praktizieren‘ oder ‚Regulierend-flexibles Managen‘ sind zu verstehen als Bewältigungsmodi der kontingenten pädagogischen (Konflikt-)Situationen, auf die sich die Fallschilderungen beziehen. Die jeweilige Lehrkraft hat dieses Muster in dem beschriebenen Fall genutzt, was allerdings keine Aussage darüber zulässt, auf welche Muster die Lehrkraft in anderen Fällen zugreifen würde. Die Ergebnisse der vorliegenden Arbeit eignen sich als eine heuristische bzw. theoretische Folie, die Lehrkräfte beim Erschließen ihres eigenen pädagogischen Handelns - etwa in einer als Fallberatung konzipierten Fortbildung - unterstützen kann. Möglich sind Anschlüsse an andere theoretische Ansätze zum Handeln von Lehrkräften aber auch deren veränderte Einordnung. Erweitert werden die Optionen, dieses Handeln über wissenschaftliche Zugänge zu erfassen.
Eye movements serve as a window into ongoing visual-cognitive processes and can thus be used to investigate how people perceive real-world scenes. A key issue for understanding eye-movement control during scene viewing is the roles of central and peripheral vision, which process information differently and are therefore specialized for different tasks (object identification and peripheral target selection respectively). Yet, rather little is known about the contributions of central and peripheral processing to gaze control and how they are coordinated within a fixation during scene viewing. Additionally, the factors determining fixation durations have long been neglected, as scene perception research has mainly been focused on the factors determining fixation locations. The present thesis aimed at increasing the knowledge on how central and peripheral vision contribute to spatial and, in particular, to temporal aspects of eye-movement control during scene viewing. In a series of five experiments, we varied processing difficulty in the central or the peripheral visual field by attenuating selective parts of the spatial-frequency spectrum within these regions. Furthermore, we developed a computational model on how foveal and peripheral processing might be coordinated for the control of fixation duration. The thesis provides three main findings. First, the experiments indicate that increasing processing demands in central or peripheral vision do not necessarily prolong fixation durations; instead, stimulus-independent timing is adapted when processing becomes too difficult. Second, peripheral vision seems to play a prominent role in the control of fixation durations, a notion also implemented in the computational model. The model assumes that foveal and peripheral processing proceed largely in parallel and independently during fixation, but can interact to modulate fixation duration. Thus, we propose that the variation in fixation durations can in part be accounted for by the interaction between central and peripheral processing. Third, the experiments indicate that saccadic behavior largely adapts to processing demands, with a bias of avoiding spatial-frequency filtered scene regions as saccade targets. We demonstrate that the observed saccade amplitude patterns reflect corresponding modulations of visual attention. The present work highlights the individual contributions and the interplay of central and peripheral vision for gaze control during scene viewing, particularly for the control of fixation duration. Our results entail new implications for computational models and for experimental research on scene perception.
Water scarcity, adaption on climate change, and risk assessment of droughts and floods are critical topics for science and society these days. Monitoring and modeling of the hydrological cycle are a prerequisite to understand and predict the consequences for weather and agriculture. As soil water storage plays a key role for partitioning of water fluxes between the atmosphere, biosphere, and lithosphere, measurement techniques are required to estimate soil moisture states from small to large scales.
The method of cosmic-ray neutron sensing (CRNS) promises to close the gap between point-scale and remote-sensing observations, as its footprint was reported to be 30 ha. However, the methodology is rather young and requires highly interdisciplinary research to understand and interpret the response of neutrons to soil moisture. In this work, the signal of nine detectors has been systematically compared, and correction approaches have been revised to account for meteorological and geomagnetic variations. Neutron transport simulations have been consulted to precisely characterize the sensitive footprint area, which turned out to be 6--18 ha, highly local, and temporally dynamic. These results have been experimentally confirmed by the significant influence of water bodies and dry roads. Furthermore, mobile measurements on agricultural fields and across different land use types were able to accurately capture the various soil moisture states. It has been further demonstrated that the corresponding spatial and temporal neutron data can be beneficial for mesoscale hydrological modeling. Finally, first tests with a gyrocopter have proven the concept of airborne neutron sensing, where increased footprints are able to overcome local effects.
This dissertation not only bridges the gap between scales of soil moisture measurements. It also establishes a close connection between the two worlds of observers and modelers, and further aims to combine the disciplines of particle physics, geophysics, and soil hydrology to thoroughly explore the potential and limits of the CRNS method.
This two-wave longitudinal study examined how developmental changes in students’ mastery goal orientation, academic effort, and intrinsic motivation were predicted by student-perceived support of motivational support (support for autonomy, competence, and relatedness) in secondary classrooms. The study extends previous knowledge that showed that support for motivational support in class is related to students’ intrinsic motivation as it focused on the developmental changes of a set of different motivational variables and the relations of these changes to student-perceived motivational support in class. Thus, differential classroom effects on students’ motivational development were investigated. A sample of 1088 German students was assessed in the beginning of the school year when students were in grade 8 (Mean age D 13.70, SD D 0.53, 54% girls) and again at the end of the next school year when students were in grade 9. Results of latent change models showed a tendency toward decline in mastery goal orientation and a significant decrease in academic effort from grade 8 to 9. Intrinsic motivation did not decrease significantly across time. Student-perceived support of competence in class predicted the level and change in students’ academic effort. The findings emphasized that it is beneficial to create classroom learning environments that enhance students’ perceptions of competence in class when aiming to enhance students’ academic effort in secondary school classrooms.
Subcultures creating culture
(2016)
The purpose of this work is to apply the methods of textual semiotics to subcultures, in particular to the little known glam subculture. Subcultures have been the main research field of the Birmingham Centre for Contemporary Cultural Studies, known for its interdisciplinary approach, and for its focus on the creative aspects of subculture. Hebdige, in particular, introduced many semiotic elements in his work, as the aberrant decoding after Eco and the cultural creativity via bricolage after Lévi-Strauss. His definition of subculture as symbolic resistance has been criticized by the following post-subcultural researchers for its abstractness and lack of cohesion.
Semiotics eventually have been expelled from the set of tools used in sociology for the analysis of subcultures. Nowadays, the studies on subcultures have a strong ethnographic focus. Due to terminological proliferation and a descriptive approach, it is difficult to compare them on a common basis.
Textual semiotics, through the concept of semiosphere developed by Lotman, allows to go back to the intuitions of Hebdige, organizing the semiotic elements already present in his work into a wider system of interpretation. The semiosphere offers a coherent theoretical horizon as a basis for further analysis, and a new methodological perspective focusing on the cultural. In this thesis for the first time the work of Lotman is applied to the study of a subculture.
Dietary approaches contribute to the prevention and treatment of type 2 diabetes. High protein diets were shown to exert beneficial as well as adverse effects on metabolism. However, it is unclear whether the protein origin plays a role in these effects. The LeguAN study investigated in detail the effects of two high protein diets, either from plant or animal origin, in type 2 diabetic patients. Both diets contained 30 EN% protein, 40 EN% carbohydrates, and 30 EN% fat. Fiber content, glycemic index, and composition of dietary fats were similar in both diets. In comparison to previous dietary habits, the fat content was exchanged for protein, while the carbohydrate intake was not modified. Overall, both high protein diets led to improvements of glycemic control, insulin sensitivity, liver fat, and cardiovascular risk markers without remarkable differences between the protein types.
Fasting glucose together with indices of insulin resistance were ameliorated by both interventions to varying extents but without significant differences between protein types. The decline of HbA1c was more pronounced in the plant protein group, whereby the improvement of insulin sensitivity in the animal protein group. The high protein intake had only slight influence on postprandial metabolism seen for free fatty acids and indices of insulin secretion, sensitivity and degradation. Except for GIP release, ingestion of animal and plant meals did not provoke differential metabolic and hormonal responses despite diverse circulating amino acid levels.
The animal protein diets led to a selective increase of fat-free mass and decrease of total fat mass, which was not significantly different from the plant protein diet. Moreover, the high protein diets potently decreased liver fat content by 42% on average which was linked to significantly diminished lipogenesis, free fatty acids flux and lipolysis in adipose tissue. Moderate decline of circulating liver enzymes was induced by both interventions. The liver fat reduction was associated with improved glucose homeostasis and insulin sensitivity which underlines the protective effect of the diets.
Blood lipid profile improved in all subjects and was probably related to the lower fat intake. Reductions in uric acid and markers of inflammation further argued for metabolic benefits of both high protein diets. Systolic and diastolic blood pressure declined only in the PP group pointing a possible role of arginine.
Kidney function was not altered by high protein consumption over 6 weeks. The rapid decrease of serum creatinine in the PP group was noteworthy and should be further investigated. Protein type did not seem to play a role but long-term studies are warranted to fully elucidate safety of high protein regimen.
Varying the source of dietary proteins did not affect the mTOR pathway in adipose tissue and blood cells under neither acute nor chronic settings. Enhancement of whole-body insulin sensitivity suggested also no alteration of mTOR and no impairment of insulin sensitivity in skeletal muscle.
A remarkable outcome was the extensive reduction of FGF21, critical regulator of metabolic processes, by approximately 50% independently of protein type. Whether hepatic ER-stress, ammonia flux or rather macronutrient preferences is behind this paradoxical finding remains to be investigated in detail.
Unlike initial expectations and previous reports plant protein based diet had no clear advantage over animal proteins. The pronounced beneficial effect of animal protein on insulin homeostasis despite high BCAA and methionine intake was certainly unexpected assuming more complex metabolic adaptations occurring upon prolonged consumption. In addition, the reduced fat intake may have also contributed to the overall improvements in both groups.
Taking into account the above observed study results, a short-term diet containing 30 EN% protein (either from plant or animal origin), 40 EN% carbohydrates, and 30 EN% fat with lower SFA amount leads to metabolic improvements in diabetic patients, regardless of protein source.
The present work is a case study contributing to the major planning project “Suedlink”. It is structured as follows: first, in a theoretical part, mandatory theories of social acceptance (Wüstenhagen et al., 2007), steps of participation (Münnich, 2014), and the governance theory (Benz and Dose, 2011) are elaborated. Secondly, the relevant methods are discussed. Thirdly, in a qualitative analytical part, the information that were gathered from the expert interviews are analyzed with the use of the aforementioned theories. In the fourth place, an empirical quantitative analysis of data regarding the public acceptance towards Suedlink is presented.
In this case study, with the use of qualitative and quantitative methods, two questions are answered: first, which governance aspects were relevant for the priority use of underground cables for the construction of high voltage direct current transmission lines? For this question, intensive document analysis and different expert interviews were conducted. Secondly, the central question of the present work addresses the question whether local or/and individual factors affect the public acceptance towards SüdLink. Here, in particular, it is interesting to analyze if the priority use of underground cables affected the people’s acceptance towards SuedLink. In order to respond to both questions, an online survey was conducted among citizen initiatives, district administrators, and individuals in social media during March till July 2016. Thereafter, the data was analyzed with the use of descriptive quantitative methods. The data shows, that underground cables not necessarily increase public acceptance (see also Menges and Beyer, 2013). On the contrary, individual and local criteria were relevant for the survey respondents. For example criteria such as the quality of participation, distance between home and transmission lines, and the additional financial burden (taxes, higher prices for electricity) were important for the evaluation. In addition, survey respondents who participated in citizen initiatives were more critical against the priority use of underground cables and SuedLink in general. Likewise, residential homeowners rejected every form of transmission lines.
Durch die Zunahme metabolischer Stoffwechselstörungen und Erkrankungen in der Weltbevölkerung wird in der Medizin und den Lebenswissenschaften vermehrt nach Präventionsstrategien und Ansatzpunkten gesucht, die die Gesundheit fördern, Erkrankungen verhindern helfen und damit auch die Gesamtlast auf die Gesundheitssysteme erleichtern. Ein Ansatzpunkt wird dabei in der Ernährung gesehen, da insbesondere der Konsum von gesättigten Fetten die Gesundheit nachträglich zu beeinflussen scheint. Dabei wird übersehen, dass in vielen Studien Hochfettdiäten nicht ausreichend von den Einflüssen einer zum Bedarf hyperkalorischen Energiezufuhr getrennt werden, sodass die Datenlage zu dem Einfluss von (gesättigten) Fetten auf den Metabolismus bei gleichbleibender Energieaufnahme noch immer unzureichend ist.
In der NUtriGenomic Analysis in Twins-Studie wurden 46 Zwillingspaare (34 monozygot, 12 dizygot) über einen Zeitraum von sechs Wochen mittels einer kohlenhydratreichen, fettarmen Diät nach Richtlinien der Deutschen Gesellschaft für Ernährung für ihr Ernährungsverhalten standardisiert, ehe sie zu einer kohlenhydratarmen, fettreichen Diät, die insbesondere gesättigte Fette enthielt, für weitere sechs Wochen wechselten. Beide Diäten waren dem individuellen Energiebedarf der Probanden angepasst, um so sowohl akut nach einerWoche als auch längerfristig nach sechs Wochen Änderungen des Metabolismus beobachten zu können, die sich in der vermehrten Aufnahme von (gesättigten) Fetten begründeten.
Die über die detaillierte Charakterisierung der Probanden an den klinischen Untersuchungstagen generierten Datensätze wurden mit statistischen und mathematischen Methoden (z.B. lineare gemischte Modellierung) analysiert, die der Größe der Datensätze und damit ihrem Informationsvolumen angepasst waren.
Es konnte gezeigt werden, dass die metabolisch gesunden und relativ jungen Probanden, die eine gute Compliance zeigten, im Hinblick auf ihren Glukosestoffwechsel adaptieren konnten, indem die Akutantwort nach einer Woche im Nüchterninsulin und dem Index für Insulinresistenz in den weiteren fünf Wochen ausgeglichen wurde.
Der Lipidstoffwechsel in Form der klassischen Marker wie Gesamtcholesterin, LDL und HDL war dagegen stärker beeinflusst und auch nach insgesamt sechs Wochen deutlich erhöht.
Letzteres unterstützt die Beobachtung im Transkriptom des weißen, subkutanen Fettgewebes, bei der eine Aktivierung der über die Toll-like receptors und das Inflammasom vermittelten subklinischen Inflammation beobachtet werden konnte.
Die auftretenden Veränderungen in Konzentration und Komposition des Plasmalipidoms zeigte ebenfalls nur eine teilweise und auf bestimmte Spezies begrenzte Gegenregulation.
Diesbezüglich kann also geschlussfolgert werden, dass auch die isokalorische Aufnahme von (gesättigten) Fetten zu Veränderungen im Metabolismus führt, wobei die Auswirkungen in weiteren (Langzeit-)Studien und Experimenten noch genauer untersucht werden müssen. Insbesondere wäre dabei ein längerer Zeitraum unter isokalorischen Bedingungen von Interesse und die Untersuchung von Probanden mit metabolischer Vorbelastung (z.B. Insulinresistenz).
Darüber hinaus konnte in NUGAT aber ebenfalls gezeigt werden, dass die Nutrigenetik und Nutrigenomik zwei nicht zu vernachlässigende Faktoren darstellen. So zeigten unter anderem die Konzentrationen einiger Lipidspezies eine starke Erblichkeit und Abhängigkeit der Diät.
Zudem legen die Ergebnisse nahe, dass laufende wie geplante Präventionsstrategien und medizinische Behandlungen deutlich stärker den Patienten als Individuum mit einbeziehen müssen, da die Datenanalyse interindividuelle Unterschiede identifizierte und Hinweise lieferte, dass einige Probanden die nachteiligen, metabolischen Auswirkungen einer Hochfettdiät besser ausgleichen konnten als andere.
Der Fall der Rachel Dolezal
(2016)
Die Amerikanerin Rachel Dolezal war bis ins Jahr 2015 als Afroamerikanerin bekannt. Als Aktivistin der National Association for the Advancement of Colored People setzte sie sich für die Rechte der afroamerikanischen Bevölkerung ein, lebte in einem schwarzen Umfeld und lehrte an einer Universität Afroamerikanische Studien. „I identify as black“ antwortete sie auf die Frage eines amerikanischen Fernsehmoderators, ob sie Afroamerikanerin sei. Ihre Kollegen und ihr näheres Umfeld identifizierten sie ebenfalls als solche. Erst, als regionale Journalisten auf sie aufmerksam wurden und ihre Eltern sich zu Wort meldeten, wurde deutlich, dass Dolezal eigentlich eine weiße Frau ist. Dolezals Eltern bestätigten dies, indem sie Kindheitsfotos einer hellhäutigen, blonden Rachel veröffentlichten. Dolezals Verhalten entfachte daraufhin eine rege mediale Diskussion über ihre Person im Kontext von Ethnizität und »Rasse«.
Die Verfasserin greift Dolezals Fall exemplarisch auf, um der Frage nachzugehen, ob ein Doing Race nach Belieben möglich ist. Darf sich Dolezal als schwarz identifizieren, obwohl sie keine afrikanischen Vorfahren hat? Welche gesellschaftliche Wissensvorräte schränken diese Wahl ein und welche Konsequenzen ergeben sich daraus? Anhand einer Diskursanalyse amerikanischer Zeitungsartikel geht die Verfasserin diesen Fragen nach. Hierbei werden »Rasse« und Ethnizität als soziale Konstruktionen, basierend auf dem Konzept von Stephen Cornell und Douglas Hartmann, betrachtet.
The optical properties of semiconductor nanocrystals (SC NCs) are largely controlled by their size and surface chemistry, i.e., the chemical composition and thickness of inorganic passivation shells and the chemical nature and number of surface ligands as well as the strength of their bonds to surface atoms. The latter is particularly important for CdTe NCs, which – together with alloyed CdxHg1−xTe – are the only SC NCs that can be prepared in water in high quality without the need for an additional inorganic passivation shell. Aiming at a better understanding of the role of stabilizing ligands for the control of the application-relevant fluorescence features of SC NCs, we assessed the influence of two of the most commonly used monodentate thiol ligands, thioglycolic acid (TGA) and mercaptopropionic acid (MPA), on the colloidal stability, photoluminescence (PL) quantum yield (QY), and PL decay behavior of a set of CdTe NC colloids. As an indirect measure for the strength of the coordinative bond of the ligands to SC NC surface atoms, the influence of the pH (pD) and the concentration on the PL properties of these colloids was examined in water and D2O and compared to the results from previous dilution studies with a set of thiol-capped Cd1−xHgxTe SC NCs in D2O. As a prerequisite for these studies, the number of surface ligands was determined photometrically at different steps of purification after SC NC synthesis with Ellman's test. Our results demonstrate ligand control of the pH-dependent PL of these SC NCs, with MPA-stabilized CdTe NCs being less prone to luminescence quenching than TGA-capped ones. For both types of CdTe colloids, ligand desorption is more pronounced in H2O compared to D2O, underlining also the role of hydrogen bonding and solvent molecules.
The collision of bathymetric anomalies, such as oceanic spreading centers, at convergent plate margins can profoundly affect subduction dynamics, magmatism, and the structural and geomorphic evolution of the overriding plate. The Southern Patagonian Andes of South America are a prime example for sustained oceanic ridge collision and the successive formation and widening of an extensive asthenospheric slab window since the Middle Miocene. Several of the predicted upper-plate geologic manifestations of such deep-seated geodynamic processes have been studied in this region, but many topics remain highly debated. One of the main controversial topics is the interpretation of the regional low-temperature thermochronology exhumational record and its relationship with tectonic and/or climate-driven processes, ultimately manifested and recorded in the landscape evolution of the Patagonian Andes. The prominent along-strike variance in the topographic characteristics of the Andes, combined with coupled trends in low-temperature thermochronometer cooling ages have been interpreted in very contrasting ways, considering either purely climatic (i.e. glacial erosion) or geodynamic (slab-window related) controlling factors.
This thesis focuses on two main aspects of these controversial topics. First, based on field observations and bedrock low-temperature thermochronology data, the thesis addresses an existing research gap with respect to the neotectonic activity of the upper plate in response to ridge collision - a mechanism that has been shown to affect the upper plate topography and exhumational patterns in similar tectonic settings. Secondly, the qualitative interpretation of my new and existing thermochronological data from this region is extended by inverse thermal modelling to define thermal histories recorded in the data and evaluate the relative importance of surface vs. geodynamic factors and their possible relationship with the regional cooling record.
My research is centered on the Northern Patagonian Icefield (NPI) region of the Southern Patagonian Andes. This site is located inboard of the present-day location of the Chile Triple Junction - the juncture between the colliding Chile Rise spreading center and the Nazca and Antarctic Plates along the South American convergent margin. As such this study area represents the region of most recent oceanic-ridge collision and associated slab window formation. Importantly, this location also coincides with the abrupt rise in summit elevations and relief characteristics in the Southern Patagonian Andes. Field observations, based on geological, structural and geomorphic mapping, are combined with bedrock apatite (U-Th)/He and apatite fission track (AHe and AFT) cooling ages sampled along elevation transects across the orogen. This new data reveals the existence of hitherto unrecognized neotectonic deformation along the flanks of the range capped by the NPI.
This deformation is associated with the closely spaced oblique collision of successive oceanic-ridge segments in this region over the past 6 Ma. I interpret that this has caused a crustal-scale partitioning of deformation and the decoupling, margin-parallel migration, and localized uplift of a large crustal sliver (the NPI block) along the subduction margin. The location of this uplift coincides with a major increase of summit elevations and relief at the northern edge of the NPI massif. This mechanism is compatible with possible extensional processes along the topographically subdued trailing edge of the NPI block as documented by very recent and possibly still active normal faulting. Taken together, these findings suggest a major structural control on short-wavelength variations in topography in the Southern Patagonian Andes - the region affected by ridge collision and slab window formation.
The second research topic addressed here focuses on using my new and existing bedrock low-temperature cooling ages in forward and inverse thermal modeling. The data was implemented in the HeFTy and QTQt modeling platforms to constrain the late Cenozoic thermal history of the Southern Patagonian Andes in the region of the most recent upper-plate sectors of ridge collision. The data set combines AHe and AFT data from three elevation transects in the region of the Northern Patagonian Icefield. Previous similar studies claimed far-reaching thermal effects of the approaching ridge collision and slab window to affect patterns of Late Miocene reheating in the modelled thermal histories. In contrast, my results show that the currently available data can be explained with a simpler thermal history than previously proposed. Accordingly, a reheating event is not needed to reproduce the observations. Instead, the analyzed ensemble of modelled thermal histories defines a Late Miocene protracted cooling and Pliocene-to-recent stepwise exhumation. These findings agree with the geological record of this region. Specifically, this record indicates an Early Miocene phase of active mountain building associated with surface uplift and an active fold-and-thrust belt, followed by a period of stagnating deformation, peneplanation, and lack of synorogenic deposition in the Patagonian foreland. The subsequent period of stepwise exhumation likely resulted from a combination of pulsed glacial erosion and coeval neotectonic activity. The differences between the present and previously published interpretation of the cooling record can be reconciled with important inconsistencies of previously used model setup. These include mainly the insufficient convergence of the models and improper assumptions regarding the geothermal conditions in the region. This analysis puts a methodological emphasis on the prime importance of the model setup and the need for its thorough examination to evaluate the robustness of the final outcome.
In this paper we report an experimental and computational study of liquid acetonitrile (H3C–C[triple bond, length as m-dash]N) by resonant inelastic X-ray scattering (RIXS) at the N K-edge. The experimental spectra exhibit clear signatures of the electronic structure of the valence states at the N site and incident-beam-polarization dependence is observed as well. Moreover, we find fine structure in the quasielastic line that is assigned to finite scattering duration and nuclear relaxation. We present a simple and light-to-evaluate model for the RIXS maps and analyze the experimental data using this model combined with ab initio molecular dynamics simulations. In addition to polarization-dependence and scattering-duration effects, we pinpoint the effects of different types of chemical bonding to the RIXS spectrum and conclude that the H2C–C[double bond, length as m-dash]NH isomer, suggested in the literature, does not exist in detectable quantities. We study solution effects on the scattering spectra with simulations in liquid and in vacuum. The presented model for RIXS proved to be light enough to allow phase-space-sampling and still accurate enough for identification of transition lines in physical chemistry research by RIXS.
The excitation of localized surface plasmons in noble metal nanoparticles (NPs) results in different nanoscale effects such as electric field enhancement, the generation of hot electrons and a temperature increase close to the NP surface. These effects are typically exploited in diverse fields such as surface-enhanced Raman scattering (SERS), NP catalysis and photothermal therapy (PTT). Halogenated nucleobases are applied as radiosensitizers in conventional radiation cancer therapy due to their high reactivity towards secondary electrons. Here, we use SERS to study the transformation of 8-bromoadenine (8BrA) into adenine on the surface of Au and AgNPs upon irradiation with a low-power continuous wave laser at 532, 633 and 785 nm, respectively. The dissociation of 8BrA is ascribed to a hot-electron transfer reaction and the underlying kinetics are carefully explored. The reaction proceeds within seconds or even milliseconds. Similar dissociation reactions might also occur with other electrophilic molecules, which must be considered in the interpretation of respective SERS spectra. Furthermore, we suggest that hot-electron transfer induced dissociation of radiosensitizers such as 8BrA can be applied in the future in PTT to enhance the damage of tumor tissue upon irradiation.
Macrocycles based on L-cystine were synthesized by ring-closing metathesis (RCM) and subsequently polymerized by entropy-driven ring-opening metathesis polymerization (ED-ROMP). Monomer conversion reached ∼80% in equilibrium and the produced poly(ester-amine-disulfide-alkene)s exhibited apparent molar masses (Mappw) of up to 80 kDa and dispersities (Đ) of ∼2. The polymers can be further functionalized with acid anhydrides and degraded by reductive cleavage of the main-chain disulfide.
Savannas cover a broad geographical range across continents and are a biome best described by a mix of herbaceous and woody plants. The former create a more or less continuous layer while the latter should be sparse enough to leave an open canopy. What has long intrigued ecologists is how these two competing plant life forms of vegetation coexist.
Initially attributed to resource competition, coexistence was considered the stable outcome of a root niche differentiation between trees and grasses. The importance of environmental factors became evident later, when data from moister environments demonstrated that tree cover was often lower than what the rainfall conditions would allow for. Our current understanding relies on the interaction of competition and disturbances in space and time. Hence, the influence of grazing and fire and the corresponding feedbacks they generate have been keenly investigated. Grazing removes grass cover, initiating a self-reinforcing process propagating tree cover expansion. This is known as the encroachment phenomenon. Fire, on the other hand, imposes a bottleneck on the tree population by halting the recruitment of young trees into adulthood. Since grasses fuel fires, a feedback linking grazing, grass cover, fire, and tree cover is created. In African savannas, which are the focus of this dissertation, these feedbacks play a major role in the dynamics.
The importance of these feedbacks came into sharp focus when the notion of alternative states began to be applied to savannas. Alternative states in ecology arise when different states of an ecosystem can occur under the same conditions. According to this an open savanna and a tree-dominated savanna can be classified as alternative states, since they can both occur under the same climatic conditions. The aforementioned feedbacks are critical in the creation of alternative states. The grass-fire feedback can preserve an open canopy as long as fire intensity and frequency remain above a certain threshold. Conversely, crossing a grazing threshold can force an open savanna to shift to a tree-dominated state. Critically, transitions between such alternative states can produce hysteresis, where a return to pre-transition conditions will not suffice to restore the ecosystem to its original state.
In the chapters that follow, I will cover aspects relating to the coexistence mechanisms and the role of feedbacks in tree-grass interactions. Coming back to the coexistence question, due to the overwhelming focus on competition and disturbance another important ecological process was neglected: facilitation. Therefore, in the first study within this dissertation I examine how facilitation can expand the tree-grass coexistence range into drier conditions. For the second study I focus on another aspect of savanna dynamics which remains underrepresented in the literature: the impacts of inter-annual rainfall variability upon savanna trees and the resilience of the savanna state. In the third and final study within this dissertation I approach the well-researched encroachment phenomenon from a new perspective: I search for an early warning indicator of the process to be used as a prevention tool for savanna conservation. In order to perform all this work I developed a mathematical ecohydrological model of Ordinary Differential Equations (ODEs) with three variables: soil moisture content, grass cover and tree cover.
Facilitation: Results showed that the removal of grass cover through grazing was detrimental to trees under arid conditions, contrary to expectation based on resource competition. The reason was that grasses preserved moisture in the soil through infiltration and shading, thus ameliorating the harsh conditions for trees in accordance with the Stress Gradient Hypothesis. The exclusion of grasses from the model further demonstrated this: tree cover was lower in the absence of grasses, indicating that the benefits of grass facilitation outweighed the costs of grass competition for trees. Thus, facilitation expanded the climatic range where savannas persisted into drier conditions.
Rainfall variability: By adjusting the model to current rainfall patterns in East Africa, I simulated conditions of increasing inter-annual rainfall variability for two distinct mean rainfall scenarios: semi-arid and mesic. Alternative states of tree-less grassland and tree-dominated savanna emerged in both cases. Increasing variability reduced semi-arid savanna tree cover to the point that at high variability the savanna state was eliminated, because variability intensified resource competition and strengthened the fire disturbance during high rainfall years. Mesic savannas, on the other hand, became more resilient along the variability gradient: increasing rainfall variability created more opportunities for the rapid growth of trees to overcome the fire disturbance, boosting the chances of savannas persisting and thus increasing mesic savanna resilience.
Preventing encroachment: The breakdown in the grass-fire feedback caused by heavy grazing promoted the expansion of woody cover. This could be irreversible due to the presence of alternative states of encroached and open savanna, which I found along a simulated grazing gradient. When I simulated different short term heavy grazing treatments followed by a reduction to the original grazing conditions, certain cases converged to the encroached state. Utilising woody cover changes only during the heavy grazing treatment, I developed an early warning indicator which identified these cases with a high risk of such hysteresis and successfully distinguished them from those with a low risk. Furthermore, after validating the indicator on encroachment data, I demonstrated that it appeared early enough for encroachment to be prevented through realistic grazing-reduction treatments.
Though this dissertation is rooted in the theory of savanna dynamics, its results can have significant applications in savanna conservation. Facilitation has only recently become a topic of interest within savanna literature. Given the threat of increasing droughts and a general anticipation of drier conditions in parts of Africa, insights stemming from this research may provide clues for preserving arid savannas. The impacts of rainfall variability on savannas have not yet been thoroughly studied, either. Conflicting results appear as a result of the lack of a robust theoretical understanding of plant interactions under variable conditions. . My work and other recent studies argue that such conditions may increase the importance of fast resource acquisition creating a ‘temporal niche’. Woody encroachment has been extensively studied as phenomenon, though not from the perspective of its early identification and prevention. The development of an encroachment forecasting tool, as the one presented in this work, could protect both the savanna biome and societies dependent upon it for (economic) survival. All studies which follow are bound by the attempt to broaden the horizons of savanna-related research in order to deal with extreme conditions and phenomena; be it through the enhancement of the coexistence debate or the study of an imminent external threat or the development of a management-oriented tool for the conservation of savannas.
We present new experimental data of the low-temperature metastable region of liquid water derived from high-density synthetic fluid inclusions (996–916 kg m−3) in quartz. Microthermometric measurements include: (i) prograde (upon heating) and retrograde (upon cooling) liquid–vapour homogenisation. We used single ultrashort laser pulses to stimulate vapour bubble nucleation in initially monophase liquid inclusions. Water densities were calculated based on prograde homogenisation temperatures using the IAPWS-95 formulation. We found retrograde liquid–vapour homogenisation temperatures in excellent agreement with IAPWS-95. (ii) Retrograde ice nucleation. Raman spectroscopy was used to determine the nucleation of ice in the absence of the vapour bubble. Our ice nucleation data in the doubly metastable region are inconsistent with the low-temperature trend of the spinodal predicted by IAPWS-95, as liquid water with a density of 921 kg m−3 remains in a homogeneous state during cooling down to a temperature of −30.5 °C, where it is transformed into ice whose density corresponds to zero pressure. (iii) Ice melting. Ice melting temperatures of up to 6.8 °C were measured in the absence of the vapour bubble, i.e. in the negative pressure region. (iv) Spontaneous retrograde and, for the first time, prograde vapour bubble nucleation. Prograde bubble nucleation occurred upon heating at temperatures above ice melting. The occurrence of prograde and retrograde vapour bubble nucleation in the same inclusions indicates a maximum of the bubble nucleation curve in the ϱ–T plane at around 40 °C. The new experimental data represent valuable benchmarks to evaluate and further improve theoretical models describing the p–V–T properties of metastable water in the low-temperature region.