Refine
Year of publication
- 2016 (1772) (remove)
Document Type
- Article (1185)
- Postprint (209)
- Doctoral Thesis (197)
- Other (69)
- Review (50)
- Monograph/Edited Volume (17)
- Preprint (16)
- Part of a Book (14)
- Conference Proceeding (6)
- Master's Thesis (4)
Language
- English (1772) (remove)
Is part of the Bibliography
- yes (1772) (remove)
Keywords
- German (11)
- Magellanic Clouds (8)
- aggression (8)
- children (8)
- climate change (8)
- prosody (8)
- sentence processing (8)
- adolescents (7)
- prevalence (7)
- self-paced reading (7)
Institute
- Institut für Biochemie und Biologie (283)
- Institut für Geowissenschaften (283)
- Institut für Physik und Astronomie (254)
- Institut für Chemie (198)
- Mathematisch-Naturwissenschaftliche Fakultät (79)
- Institut für Ernährungswissenschaft (75)
- Institut für Mathematik (71)
- Department Psychologie (62)
- Department Linguistik (53)
- Humanwissenschaftliche Fakultät (40)
Species can adjust their traits in response to selection which may strongly influence species coexistence. Nevertheless, current theory mainly assumes distinct and time-invariant trait values. We examined the combined effects of the range and the speed of trait adaptation on species coexistence using an innovative multispecies predator–prey model. It allows for temporal trait changes of all predator and prey species and thus simultaneous coadaptation within and among trophic levels. We show that very small or slow trait adaptation did not facilitate coexistence because the stabilizing niche differences were not sufficient to offset the fitness differences. In contrast, sufficiently large and fast trait adaptation jointly promoted stable or neutrally stable species coexistence. Continuous trait adjustments in response to selection enabled a temporally variable convergence and divergence of species traits; that is, species became temporally more similar (neutral theory) or dissimilar (niche theory) depending on the selection pressure, resulting over time in a balance between niche differences stabilizing coexistence and fitness differences promoting competitive exclusion. Furthermore, coadaptation allowed prey and predator species to cluster into different functional groups. This equalized the fitness of similar species while maintaining sufficient niche differences among functionally different species delaying or preventing competitive exclusion. In contrast to pre-
vious studies, the emergent feedback between biomass and trait dynamics enabled supersaturated coexistence for a broad range of potential trait adaptation and parameters. We conclude that accounting for trait adaptation may explain stable and supersaturated species coexistence for a broad range of environmental conditions in natural systems when the absence of such adaptive changes would preclude it. Small trait changes, coincident with those that may occur within many natural populations, greatly enlarged the number of coexisting species.
Species can adjust their traits in response to selection which may strongly influence species coexistence. Nevertheless, current theory mainly assumes distinct and time-invariant trait values. We examined the combined effects of the range and the speed of trait adaptation on species coexistence using an innovative multispecies predator–prey model. It allows for temporal trait changes of all predator and prey species and thus simultaneous coadaptation within and among trophic levels. We show that very small or slow trait adaptation did not facilitate coexistence because the stabilizing niche differences were not sufficient to offset the fitness differences. In contrast, sufficiently large and fast trait adaptation jointly promoted stable or neutrally stable species coexistence. Continuous trait adjustments in response to selection enabled a temporally variable convergence and divergence of species traits; that is, species became temporally more similar (neutral theory) or dissimilar (niche theory) depending on the selection pressure, resulting over time in a balance between niche differences stabilizing coexistence and fitness differences promoting competitive exclusion. Furthermore, coadaptation allowed prey and predator species to cluster into different functional groups. This equalized the fitness of similar species while maintaining sufficient niche differences among functionally different species delaying or preventing competitive exclusion. In contrast to previous studies, the emergent feedback between biomass and trait dynamics enabled supersaturated coexistence for a broad range of potential trait adaptation and parameters. We conclude that accounting for trait adaptation may explain stable and supersaturated species coexistence for a broad range of environmental conditions in natural systems when the absence of such adaptive changes would preclude it. Small trait changes, coincident with those that may occur within many natural populations, greatly enlarged the number of coexisting species.
Species can adjust their traits in response to selection which may strongly influence species coexistence. Nevertheless, current theory mainly assumes distinct and time-invariant trait values. We examined the combined effects of the range and the speed of trait adaptation on species coexistence using an innovative multispecies predator-prey model. It allows for temporal trait changes of all predator and prey species and thus simultaneous coadaptation within and among trophic levels. We show that very small or slow trait adaptation did not facilitate coexistence because the stabilizing niche differences were not sufficient to offset the fitness differences. In contrast, sufficiently large and fast trait adaptation jointly promoted stable or neutrally stable species coexistence. Continuous trait adjustments in response to selection enabled a temporally variable convergence and divergence of species traits; that is, species became temporally more similar (neutral theory) or dissimilar (niche theory) depending on the selection pressure, resulting over time in a balance between niche differences stabilizing coexistence and fitness differences promoting competitive exclusion. Furthermore, coadaptation allowed prey and predator species to cluster into different functional groups. This equalized the fitness of similar species while maintaining sufficient niche differences among functionally different species delaying or preventing competitive exclusion. In contrast to previous studies, the emergent feedback between biomass and trait dynamics enabled supersaturated coexistence for a broad range of potential trait adaptation and parameters. We conclude that accounting for trait adaptation may explain stable and supersaturated species coexistence for a broad range of environmental conditions in natural systems when the absence of such adaptive changes would preclude it. Small trait changes, coincident with those that may occur within many natural populations, greatly enlarged the number of coexisting species.
Well-developed phonological awareness skills are a core prerequisite for early literacy development. Although effective phonological awareness training programs exist, children at risk often do not reach similar levels of phonological awareness after the intervention as children with normally developed skills. Based on theoretical considerations and first promising results the present study explores effects of an early musical training in combination with a conventional phonological training in children with weak phonological awareness skills. Using a quasi-experimental pretest-posttest control group design and measurements across a period of 2 years, we tested the effects of two interventions: a consecutive combination of a musical and a phonological training and a phonological training alone. The design made it possible to disentangle effects of the musical training alone as well the effects of its combination with the phonological training. The outcome measures of these groups were compared with the control group with multivariate analyses, controlling for a number of background variables. The sample included N = 424 German-speaking children aged 4–5 years at the beginning of the study. We found a positive relationship between musical abilities and phonological awareness. Yet, whereas the well-established phonological training produced the expected effects, adding a musical training did not contribute significantly to phonological awareness development. Training effects were partly dependent on the initial level of phonological awareness. Possible reasons for the lack of training effects in the musical part of the combination condition as well as practical implications for early literacy education are discussed.
Reconstructions of the deposition rate of windblown mineral dust in ocean sediments offer an important means of tracking past climate changes and of assessing the radiative and biogeochemical impacts of dust in past climates. Dust flux estimates in ocean sediments have commonly been based on the operationally defined lithogenic fraction of sediment samples. More recently, dust fluxes have been estimated from measurements of helium and thorium, as rare isotopes of these elements (He-3 and Th-230) allow estimates of sediment flux, and the dominant isotopes (He-4 and Th-232) are uniquely associated with the lithogenic fraction of marine sediments. In order to improve the fidelity of dust flux reconstructions based on He and Th, we present a survey of He and Th concentrations in sediments from dust source areas in East Asia, Australia and South America. Our data show systematic relationships between He and Th concentrations and grain size, with He concentrations decreasing and Th concentrations increasing with decreasing grain size. We find consistent He and Th concentrations in the fine fraction (<5 mu m) of samples from East Asia, Australia and Central South America (Puna-Central West Argentina), with Th concentrations averaging 14 mu g/g and He concentrations averaging 2 mu cc STP/g. We recommend use of these values for estimating dust fluxes in sediments where dust is dominantly fine-grained, and suggest that previous studies may have systematically overestimated Th-based dust fluxes by 30%. Source areas in Patagonia appear to have lower He and Th contents than other regions, as fine fraction concentrations average 0.8 mu cc STP/g and 9 mu g/g for He-4 and Th-232, respectively. The impact of grain size on lithogenic He and Th concentrations should be taken into account in sediments proximal to dust sources where dust grain size may vary considerably. Our data also have important implications for the hosts of He in long-traveled dust and for the He-3/He-4 ratio used for terrigenous He in studies of extraterrestrial He in sediments and ice. We also investigate the use of He/Th ratios as a provenance tracer. Our results suggest differences in fine fraction He/Th ratios between East Asia, Australia, central South America and Patagonia, with ratios showing a positive relationship with the geological age of source rocks. He/Th ratios may thus provide useful provenance information, for example allowing separation of Patagonian sources from Puna-Central West Argentina or Australian dust sources. He/Th ratios in open-ocean marine sediments are similar to ratios in the fine fraction of upwind dust source areas. He/Th ratios in mid-latitude South Atlantic sediments suggest that dust in this region primarily derives from the Puna-Central West Argentina region (23-32 degrees S) rather than Patagonia (>38 degrees S). In the equatorial Pacific, He/Th ratios are much lower than in extratropical Pacific sediments or potential source areas measured as a part of this study (East Asia, South America, Australia) for reasons that are at present unclear, complicating their use as provenance tracers in this region. (C) 2015 Elsevier Ltd. All rights reserved.
The horse is a fascinating animal symbolizing power, beauty, strength and grace. Among all the animal species domesticated the horse had the largest impact on the course of human history due to its importance for warfare and transportation. Studying the process of horse domestication contributes to the knowledge about the history of horses and even of our own species.
Research based on molecular methods has increasingly focused on the genetic basis of horse domestication. Mitochondrial DNA (mtDNA) analyses of modern and ancient horses detected immense maternal diversity, probably due to many mares that contributed to the domestic population. However, mtDNA does not provide an informative phylogeographic structure. In contrast, Y chromosome analyses displayed almost complete uniformity in modern stallions but relatively high diversity in a few ancient horses. Further molecular markers that seem to be well suited to infer the domestication history of horses or genetic and phenotypic changes during this process are loci associated with phenotypic traits.
This doctoral thesis consists of three different parts for which I analyzed various single nucleotide polymorphisms (SNPs) associated with coat color, locomotion or Y chromosomal variation of horses. These SNPs were genotyped in 350 ancient horses from the Chalcolithic (5,000 BC) to the Middle Ages (11th century). The distribution of the samples ranges from China to the Iberian Peninsula and Iceland. By applying multiplexed next-generation sequencing (NGS) I sequenced short amplicons covering the relevant positions: i) eight coat-color-associated mutations in six genes to deduce the coat color phenotype; ii) the so-called ’Gait-keeper’ SNP in the DMRT3 gene to screen for the ability to amble; iii) 16 SNPs previously detected in ancient horses to infer the corresponding haplotype. Based on these data I investigated the occurrence and frequencies of alleles underlying the respective phenotypes as well as Y chromosome haplotypes at different times and regions. Also, selection coefficients for several Y chromosome lineages or phenotypes were estimated.
Concerning coat color differences in ancient horses my work constitutes the most comprehensive study to date. I detected an increase of chestnut horses in the Middle Ages as well as differential selection for spotted and solid phenotypes over time which reflects changing human preferences.
With regard to ambling horses, the corresponding allele was present in medieval English and Icelandic horses. Based on these results I argue that Norse settlers, who frequently invaded parts of Britain, brought ambling individuals to Iceland from the British Isles which can be regarded the origin of this trait. Moreover, these settlers appear to have selected for ambling in Icelandic horses.
Relating to the third trait, the paternal diversity, these findings represent the largest ancient dataset of Y chromosome variation in non-humans. I proved the existence of several Y chromosome haplotypes in early domestic horses. The decline of Y chromosome variation coincides with the movement of nomadic peoples from the Eurasian steppes and later with different breeding practices in the Roman period.
In conclusion, positive selection was estimated for several phenotypes/lineages
in different regions or times which indicates that these were preferred by humans. Furthermore, I could successfully infer the distribution and dispersal of horses in association with human movements and actions. Thereby, a better understanding of the influence of people on the changing appearance and genetic diversity of domestic horses could be gained. My results also emphasize the close relationship of ancient genetics and archeology or history and that only in combination well-founded conclusions can be reached.
When realizing a programming language as VM, implementing behavior as part of the VM, as primitive, usually results in reduced execution times. But supporting and developing primitive functions requires more effort than maintaining and using code in the hosted language since debugging is harder, and the turn-around times for VM parts are higher. Furthermore, source artifacts of primitive functions are seldom reused in new implementations of the same language. And if they are reused, the existing API usually is emulated, reducing the performance gains. Because of recent results in tracing dynamic compilation, the trade-off between performance and ease of implementation, reuse, and changeability might now be decided adversely.
In this work, we investigate the trade-offs when creating primitives, and in particular how large a difference remains between primitive and hosted function run times in VMs with tracing just-in-time compiler. To that end, we implemented the algorithmic primitive BitBlt three times for RSqueak/VM. RSqueak/VM is a Smalltalk VM utilizing the PyPy RPython toolchain. We compare primitive implementations in C, RPython, and Smalltalk, showing that due to the tracing just-in-time compiler, the performance gap has lessened by one magnitude to one magnitude.
Arsenosugars are water-soluble arsenic species predominant in marine algae and other seafood including mussels and oysters. They typically occur at levels ranging from 2 to 50 mg arsenic/kg dry weight. Most of the arsenosugars contain arsenic as a dimethylarsinoyl group (Me2As(O)-), commonly referred to as the oxo forms, but thio analogues have also been identified in marine organisms and as metabolic products of oxo-arsenosugars. So far, no data regarding toxicity and toxicokinetics of thio-arsenosugars are available. This in vitro-based study indicates that thio-dimethylarsenosugar-glycerol exerts neither pronounced cytotoxicity nor genotoxicity even though this arsenical was bioavailable to human hepatic (HepG2) and urothelial (UROtsa) cells. Experiments with the Caco-2 intestinal barrier model mimicking human absorption indicate for the thio-arsenosugar-glycerol higher intestinal bioavailability as compared to the oxo-arsenosugars. Nevertheless, absorption estimates were much lower in comparison to other arsenicals including arsenite and arsenic-containing hydrocarbons. Arsenic speciation in cell lysates revealed that HepG2 cells are able to metabolise the thio-arsenosugar-glycerol to some extent to dimethylarsinic acid (DMA). These first in vitro data cannot fully exclude risks to human health related to the presence of thio-arsenosugars in food. (C) 2016 Elsevier GmbH. All rights reserved.
Towards the assimilation of tree-ring-width records using ensemble Kalman filtering techniques
(2016)
This paper investigates the applicability of the Vaganov–Shashkin–Lite (VSL) forward model for tree-ring-width chronologies as observation operator within a proxy data assimilation (DA) setting. Based on the principle of limiting factors, VSL combines temperature and moisture time series in a nonlinear fashion to obtain simulated TRW chronologies. When used as observation operator, this modelling approach implies three compounding, challenging features: (1) time averaging, (2) “switching recording” of 2 variables and (3) bounded response windows leading to “thresholded response”. We generate pseudo-TRW observations from a chaotic 2-scale dynamical system, used as a cartoon of the atmosphere-land system, and attempt to assimilate them via ensemble Kalman filtering techniques. Results within our simplified setting reveal that VSL’s nonlinearities may lead to considerable loss of assimilation skill, as compared to the utilization of a time-averaged (TA) linear observation operator. In order to understand this undesired effect, we embed VSL’s formulation into the framework of fuzzy logic (FL) theory, which thereby exposes multiple representations of the principle of limiting factors. DA experiments employing three alternative growth rate functions disclose a strong link between the lack of smoothness of the growth rate function and the loss of optimality in the estimate of the TA state. Accordingly, VSL’s performance as observation operator can be enhanced by resorting to smoother FL representations of the principle of limiting factors. This finding fosters new interpretations of tree-ring-growth limitation processes.
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.
The article focuses on comparative complementisers in comparative clauses expressing inequality in various languages, with particular attention paid to their role as lexicalising negative polarity. I argue that the relevant property follows from degree semantics, in that the comparative subclause encodes the inequality of the degree expressed by a matrix clausal element and the one expressed by the comparative operator. Just like ordinary negation, this has to be encoded overtly; however, as it does not constitute an instance of genuine clausal negation, the property cannot be encoded by an operator, and hence must be realised on a functional head, which is either the complementiser or a separate polarity head.
In experiments investigating sentence processing, eye movement measures such as fixation durations and regression proportions while reading are commonly used to draw conclusions about processing difficulties. However, these measures are the result of an interaction of multiple cognitive levels and processing strategies and thus are only indirect indicators of processing difficulty. In order to properly interpret an eye movement response, one has to understand the underlying principles of adaptive processing such as trade-off mechanisms between reading speed and depth of comprehension that interact with task demands and individual differences. Therefore, it is necessary to establish explicit models of the respective mechanisms as well as their causal relationship with observable behavior. There are models of lexical processing and eye movement control on the one side and models on sentence parsing and memory processes on the other. However, no model so far combines both sides with explicitly defined linking assumptions.
In this thesis, a model is developed that integrates oculomotor control with a parsing mechanism and a theory of cue-based memory retrieval. On the basis of previous empirical findings and independently motivated principles, adaptive, resource-preserving mechanisms of underspecification are proposed both on the level of memory access and on the level of syntactic parsing. The thesis first investigates the model of cue-based retrieval in sentence comprehension of Lewis & Vasishth (2005) with a comprehensive literature review and computational modeling of retrieval interference in dependency processing. The results reveal a great variability in the data that is not explained by the theory. Therefore, two principles, 'distractor prominence' and 'cue confusion', are proposed as an extension to the theory, thus providing a more adequate description of systematic variance in empirical results as a consequence of experimental design, linguistic environment, and individual differences. In the remainder of the thesis, four interfaces between parsing and eye movement control are defined: Time Out, Reanalysis, Underspecification, and Subvocalization. By comparing computationally derived predictions with experimental results from the literature, it is investigated to what extent these four interfaces constitute an appropriate elementary set of assumptions for explaining specific eye movement patterns during sentence processing. Through simulations, it is shown how this system of in itself simple assumptions results in predictions of complex, adaptive behavior.
In conclusion, it is argued that, on all levels, the sentence comprehension mechanism seeks a balance between necessary processing effort and reading speed on the basis of experience, task demands, and resource limitations. Theories of linguistic processing therefore need to be explicitly defined and implemented, in particular with respect to linking assumptions between observable behavior and underlying cognitive processes. The comprehensive model developed here integrates multiple levels of sentence processing that hitherto have only been studied in isolation. The model is made publicly available as an expandable framework for future studies of the interactions between parsing, memory access, and eye movement control.
As the world cannot be adequately understood from the vantage point of a single language, the literatures of the world can no longer be trimmed to a single world literature in the Goethean sense. This recognition bodes well for the future of philology and of literary production. Through multiperspectival writing, knowledge of life may be attainable without being reduced to a single political, medial, cartographical, geocultural, or aesthetic logic. As a laboratory for polylogical thinking, literature does not represent reality, as Erich Auerbach put it. Rather, it represents multiple lived, experienced, or relivable realities. Whoever is open to a polylogical reception of the literatures of the world can perceive and experience how life knowledge transforms into lived knowledge and how knowledge for survival turns into knowledge for living together. However, literature can be more than it is only if it stays aware of the void, of lack, of privation, of the interminable: aware of the end that never is an end. Such a planetary concept of the literatures of the world offers valuable opportunities to all those who do not fall into the trap of contenting themselves with a supposed abundance of text.
Touring Katutura!
(2016)
Guided sightseeing tours of the former township of Katutura have been offered in Windhoek since the mid-1990s. City tourism in the Namibian capital had thus become, at quite an early point in time, part of the trend towards utilising poor urban areas for purposes of tourism – a trend that set in at the beginning of the same decade. Frequently referred to as “slum tourism” or “poverty tourism”, the phenomenon of guided tours around places of poverty has not only been causing some media sensation and much public outrage since its emergence; in the past few years, it has developed into a vital field of scientific research, too. “Global Slumming” provides the grounds for a rethinking of the relationship between poverty and tourism in world society.
This book is the outcome of a study project of the Institute of Geography at the School of Cultural Studies and Social Science of the University of Osnabrueck, Germany. It represents the first empirical case study on township tourism in Namibia. It focuses on four aspects:
1. Emergence, development and (market) structure of township tourism in Windhoek
2. Expectations/imaginations, representations as well as perceptions of the township and its inhabitants from the tourist’s perspective
3. Perception and assessment of township tourism from the residents’ perspective
4. Local economic effects and the poverty-alleviating impact of township tourism
The aim is to make an empirical contribution to the discussion around the tourism-poverty nexus and to an understanding of the global phenomenon of urban poverty tourism.
Total protein concentration (TPC) is a key parameter in many biochemical experiments and its quantification is often necessary for isolation, separation, and analysis of proteins. A sensitive and rapid nanobead-based TPC quantification assay based on Forster Resonance Energy Transfer (FRET) has been developed. A new, highly luminescent Tb(III) complex has been synthesised and applied as donor in this FRET assay with an organic dye (Cy5) as acceptor. FRET-induced changes in luminescence have been investigated both at donor and acceptor emission wavelength using time-resolved luminescence spectroscopy with time-gated detection. In the assay, the Tb(III) complex and fine-tuned polyglycidyl methacrylate (PGMA) nanobeads ensure that an improvement in sensitivity and background reduction is achieved. Using 40 nm large PGMA nanobeads loaded with the Tb(III) complex, it is possible to determine TPC down to 50 ng mL(-1) in just 10 minutes. Through specific assay components the sensitivity has been improved when compared to existing nanobead-based assays and to currently known commercial methods. Additionally, the assay is relatively insensitive to the presence of contaminants, such as non-ionic detergents commonly found in biological samples. Due to no need for any centrifugal steps, this mix-and-measure bioassay can easily be implemented into routine TPC quantification protocols in biochemical laboratories.
This study presents new insights into null subjects, topic drop and the interpretation of topic-dropped elements. Besides providing an empirical data survey, it offers explanations to well-known problems, e.g. syncretisms in the context of null-subject licensing or the marginality of dropping an element which carries oblique case. The book constitutes a valuable source for both empirically and theoretically interested (generative) linguists.
To turn or not to turn?
(2016)
Bacteria typically swim in straight runs, interruped by sudden turning events. In particular, some species are limited to a reversal in the swimming direction as the only turning maneuver at their disposal. In a recent article, Grossmann et al (2016 New J. Phys. 18 043009) introduce a theoretical framework to analyze the diffusive properties of active particles following this type of run-and-reverse pattern. Based on a stochastic clock model to mimic the regulatory pathway that triggers reversal events, they show that a run-and-reverse swimmer can optimize its diffusive spreading by tuning the reversal rate according to the level of rotational noise. With their approach, they open up promising new perspectives of how to incorporate the dynamics of intracellular signaling into coarse-grained active particle descriptions.
Forecasting the onset and withdrawal of the Indian summer monsoon is crucial for the life and prosperity of more than one billion inhabitants of the Indian subcontinent. However, accurate prediction of monsoon timing remains a challenge, despite numerous efforts. Here we present a method for prediction of monsoon timing based on a critical transition precursor. We identify geographic regions-tipping elements of the monsoon-and use them as observation locations for predicting onset and withdrawal dates. Unlike most predictability methods, our approach does not rely on precipitation analysis but on air temperature and relative humidity, which are well represented both in models and observations. The proposed method allows to predict onset 2 weeks earlier and withdrawal dates 1.5 months earlier than existing methods. In addition, it enables to correctly forecast monsoon duration for some anomalous years, often associated with El Nino-Southern Oscillation.
We contribute to the theoretical understanding of randomized search heuristics by investigating their optimization behavior on satisfiable random k-satisfiability instances both in the planted solution model and the uniform model conditional on satisfiability. Denoting the number of variables by n, our main technical result is that the simple () evolutionary algorithm with high probability finds a satisfying assignment in time when the clause-variable density is at least logarithmic. For low density instances, evolutionary algorithms seem to be less effective, and all we can show is a subexponential upper bound on the runtime for densities below . We complement these mathematical results with numerical experiments on a broader density spectrum. They indicate that, indeed, the () EA is less efficient on lower densities. Our experiments also suggest that the implicit constants hidden in our main runtime guarantee are low. Our main result extends and considerably improves the result obtained by Sutton and Neumann (Lect Notes Comput Sci 8672:942-951, 2014) in terms of runtime, minimum density, and clause length. These improvements are made possible by establishing a close fitness-distance correlation in certain parts of the search space. This approach might be of independent interest and could be useful for other average-case analyses of randomized search heuristics. While the notion of a fitness-distance correlation has been around for a long time, to the best of our knowledge, this is the first time that fitness-distance correlation is explicitly used to rigorously prove a performance statement for an evolutionary algorithm.
Two experiments examined how individuals respond to a restriction presented within an approach versus an avoidance frame. In Study 1, working on a problem-solving task, participants were initially free to choose their strategy, but for a second task were told to change their strategy. The message to change was embedded in either an approach or avoidance frame. When confronted with an avoidance compared to an approach frame, the participants’ reactance toward the request was greater and, in turn, led to impaired performance. The role of reactance as a response to threat to freedom was explicitly examined in Study 2, in which participants evaluated a potential change in policy affecting their program of study herein explicitly varying whether a restriction was present or absent and whether the message was embedded in an approach versus avoidance frame. When communicated with an avoidance frame and as a restriction, participants showed the highest resistance in terms of reactance, message agreement and evaluation of the communicator. The difference in agreement with the change was mediated by reactance only when a restriction was present. Overall, avoidance goal frames were associated with more resistance to change on different levels of experience (reactance, performance, and person perception). Reactance mediated the effect of goal frame on other outcomes only when a restriction was present.
Two experiments examined how individuals respond to a restriction presented within an approach versus an avoidance frame. In Study 1, working on a problem-solving task, participants were initially free to choose their strategy, but for a second task were told to change their strategy. The message to change was embedded in either an approach or avoidance frame. When confronted with an avoidance compared to an approach frame, the participants’ reactance toward the request was greater and, in turn, led to impaired performance. The role of reactance as a response to threat to freedom was explicitly examined in Study 2, in which participants evaluated a potential change in policy affecting their program of study herein explicitly varying whether a restriction was present or absent and whether the message was embedded in an approach versus avoidance frame. When communicated with an avoidance frame and as a restriction, participants showed the highest resistance in terms of reactance, message agreement and evaluation of the communicator. The difference in agreement with the change was mediated by reactance only when a restriction was present. Overall, avoidance goal frames were associated with more resistance to change on different levels of experience (reactance, performance, and person perception). Reactance mediated the effect of goal frame on other outcomes only when a restriction was present.
Two experiments examined how individuals respond to a restriction presented within an approach versus an avoidance frame. In Study 1, working on a problem-solving task, participants were initially free to choose their strategy, but for a second task were told to change their strategy. The message to change was embedded in either an approach or avoidance frame. When confronted with an avoidance compared to an approach frame, the participants’ reactance toward the request was greater and, in turn, led to impaired performance. The role of reactance as a response to threat to freedom was explicitly examined in Study 2, in which participants evaluated a potential change in policy affecting their program of study herein explicitly varying whether a restriction was present or absent and whether the message was embedded in an approach versus avoidance frame. When communicated with an avoidance frame and as a restriction, participants showed the highest resistance in terms of reactance, message agreement and evaluation of the communicator. The difference in agreement with the change was mediated by reactance only when a restriction was present. Overall, avoidance goal frames were associated with more resistance to change on different levels of experience (reactance, performance, and person perception). Reactance mediated the effect of goal frame on other outcomes only when a restriction was present.
Theses
(2016)
Responsive inverse opal hydrogels functionalized by boroxole moieties were synthesized and explored as sensor platforms for various low molar mass as well as polymeric diols and polyols, including saccharides, glycopolymers and catechols, by exploiting the diol induced modulation of their structural color. The underlying thermoresponsive water-soluble copolymers and hydrogels exhibit a coil-to-globule or volume phase transition, respectively, of the LCST-type. They were prepared from oligoethylene oxide methacrylate (macro)monomers and functionalized via copolymerization to bear benzoboroxole moieties. The resulting copolymers represent weak polyacids, which can bind specifically to diols within an appropriate pH window. Due to the resulting modulation of the overall hydrophilicity of the systems and the consequent shift of their phase transition temperature, the usefulness of such systems for indicating the presence of catechols, saccharides, and glycopolymers was studied, exploiting the diol/polyol induced shifts of the soluble polymers’ cloud point, or the induced changes of the hydrogels’ swelling. In particular, the increased acidity of benzoboroxoles compared to standard phenylboronic acids allowed performing the studies in PBS buffer (phosphate buffered saline) at the physiologically relevant pH of 7.4. The inverse opals constructed of these thermo- and analyte-responsive hydrogels enabled following the binding of specific diols by the induced shift of the optical stop band. Their highly porous structure enabled the facile and specific optical detection of not only low molar mass but also of high molar mass diol/polyol analytes such as glycopolymers. Accordingly, such thermoresponsive inverse opal systems functionalized with recognition units represent attractive and promising platforms for the facile sensing of even rather big analytes by simple optical means, or even by the bare eye.
The authors report on the fabrication of a thermoresponsive biosensor for the amperometric detection of glucose. Screen printed electrodes with heatable gold working electrodes were modified by a thermoresponsive statistical copolymer [polymer I: poly(omega-ethoxytriethylenglycol methacrylate-omega-3-(N,N-dimethyl-N-2-methacryloyloxyethyl ammonio) propanesulfonate-co-omega-butoxydiethylenglycol methacrylate-co-2-(4-benzoyl-phenoxy)ethyl methacrylate)] with a lower critical solution temperature of around 28 degrees C in aqueous solution via electrochemically induced codeposition with a pH-responsive redox-polymer [polymer II: poly(glycidyl methacrylate-co-allyl methacrylate-co-poly(ethylene glycol) methacrylate-co-butyl acrylate-co-2-(dimethylamino) ethyl methacrylate)-[Os(bpy)(2)(4-(((2-(2-(2-aminoethoxy) ethoxy) ethyl) amino) methyl)-N,N-dimethylpicolinamide)](2+)] and pyrroloquinoline quinone-soluble glucose dehydrogenase acting as biological recognition element. Polymer II bears covalently bound Os-complexes that act as redox mediators for shuttling electrons between the enzyme and the electrode surface. Polymer I acts as a temperature triggered immobilization matrix. Probing the catalytic current as a function of the working electrode temperature shows that the activity of the biosensor is dramatically reduced above the phase transition temperature of polymer I. Thus, the local modulation of the temperature at the interphase between the electrode and the bioactive layer allows switching the biosensor from an on-to an off-state without heating of the surrounding analyte solution. (C) 2015 American Vacuum Society.
A series of hydrophobically end-capped linear triblock copolymers as well as of three-arm and four-arm star block copolymers was synthesized in a one-pot procedure from N,N-dimethylacrylamide (DMA) and N, N-diethylacrylamide (DEA). The sequential reversible addition-fragmentation chain transfer (RAFT) polymerization of these monomers via the R-approach using bi-, tri- and tetrafunctional chain transfer agents (CrAs) bearing hydrophobic dodecyl moieties proceeded in a well-controlled manner up to almost quantitative conversion. Polymers with molar masses up to 150 kDa, narrow molar mass distribution (PDI <= 1.3) and high end group functionality were obtained, which are thermoresponsive in aqueous solution showing a LCST (lower critical solution temperature) transition. The temperature-dependent associative behavior of the polymers was examined using turbidimetry, static and dynamic light scattering (SLS, DLS), and small angle neutron scattering (SANS) for structural analysis. At 25 degrees C, the polymers form weak transient networks, and rather small hydrophobic domains are already present for polymer concentrations of 5 wt%. However, when heating above the LCST transition (35-40 degrees C) of the PDEA blocks, the enhanced formation of hydrophobic domains is observed by means of light and neutron scattering. These domains have a size of about 12-15 nm and must be effectively physically cross-linked as they induce high viscosity for the more concentrated samples. SANS shows that these domains are ordered as evidenced by the appearance of a correlation peak. The copolymer architecture affects in particular the extent of ordering as the four-arm star block copolymer shows much more repulsive interactions compared to the analogous copolymers with a lower number of arms. (C) 2016 Elsevier Ltd. All rights reserved.
Thermophony in real gases
(2016)
A thermophone is an electrical device for sound generation. The advantages of thermophones over conventional sound transducers such as electromagnetic, electrostatic or piezoelectric transducers are their operational principle which does not require any moving parts, their resonance-free behavior, their simple construction and their low production costs.
In this PhD thesis, a novel theoretical model of thermophonic sound generation in real gases has been developed. The model is experimentally validated in a frequency range from 2 kHz to 1 MHz by testing more then fifty thermophones of different materials, including Carbon nano-wires, Titanium, Indium-Tin-Oxide, different sizes and shapes for sound generation in gases such as air, argon, helium, oxygen, nitrogen and sulfur hexafluoride.
Unlike previous approaches, the presented model can be applied to different kinds of thermophones and various gases, taking into account the thermodynamic properties of thermophone materials and of adjacent gases, degrees of freedom and the volume occupied by the gas atoms and molecules, as well as sound attenuation effects, the shape and size of the thermophone surface and the reduction of the generated acoustic power due to photonic emission. As a result, the model features better prediction accuracy than the existing models by a factor up to 100. Moreover, the new model explains previous experimental findings on thermophones which can not be explained with the existing models.
The acoustic properties of the thermophones have been tested in several gases using unique, highly precise experimental setups comprising a Laser-Doppler-Vibrometer combined with a thin polyethylene film which acts as a broadband and resonance-free sound-pressure detector. Several outstanding properties of the thermophones have been demonstrated for the first time, including the ability to generate arbitrarily shaped acoustic signals, a greater acoustic efficiency compared to conventional piezoelectric and electrostatic airborne ultrasound transducers, and applicability as powerful and tunable sound sources with a bandwidth up to the megahertz range and beyond.
Additionally, new applications of thermophones such as the study of physical properties of gases, the thermo-acoustic gas spectroscopy, broad-band characterization of transfer functions of sound and ultrasound detection systems, and applications in non-destructive materials testing are discussed and experimentally demonstrated.
Widespread landscape changes are presently observed in the Arctic and are most likely to
accelerate in the future, in particular in permafrost regions which are sensitive to climate warming. To assess current and future developments, it is crucial to understand past
environmental dynamics in these landscapes. Causes and interactions of environmental variability can hardly be resolved by instrumental records covering modern time scales. However, long-term
environmental variability is recorded in paleoenvironmental archives. Lake sediments are important archives that allow reconstruction of local limnogeological processes as well as past environmental changes driven directly or indirectly by climate dynamics. This study aims at
reconstructing Late Quaternary permafrost and thermokarst dynamics in central-eastern Beringia,
the terrestrial land mass connecting Eurasia and North America during glacial sea-level low stands. In order to investigate development, processes and influence of thermokarst dynamics, several sediment cores from extant lakes and drained lake basins were analyzed to answer the
following research questions:
1. When did permafrost degradation and thermokarst lake development take place and what were enhancing and inhibiting environmental factors?
2. What are the dominant processes during thermokarst lake development and how are
they reflected in proxy records?
3. How did, and still do, thermokarst dynamics contribute to the inventory and properties of organic matter in sediments and the carbon cycle?
Methods applied in this study are based upon a multi-proxy approach combining
sedimentological, geochemical, geochronological, and micropaleontological analyses, as well as
analyses of stable isotopes and hydrochemistry of pore-water and ice. Modern field observations of water quality and basin morphometrics complete the environmental investigations.
The investigated sediment cores reveal permafrost degradation and thermokarst dynamics on different time scales. The analysis of a sediment core from GG basin on the northern Seward
Peninsula (Alaska) shows prevalent terrestrial accumulation of yedoma throughout the Early to
Mid Wisconsin with intermediate wet conditions at around 44.5 to 41.5 ka BP. This first wetland
development was terminated by the accumulation of a 1-meter-thick airfall tephra most likely originating from the South Killeak Maar eruption at 42 ka BP. A depositional hiatus between 22.5 and 0.23 ka BP may indicate thermokarst lake formation in the surrounding of the site which forms a yedoma upland till today. The thermokarst lake forming GG basin initiated 230 ± 30 cal a
BP and drained in Spring 2005 AD. Four years after drainage the lake talik was still unfrozen below 268 cm depth.
A permafrost core from Mama Rhonda basin on the northern Seward Peninsula preserved a
full lacustrine record including several lake phases. The first lake generation developed at 11.8 cal ka BP during the Lateglacial-Early Holocene transition; its old basin (Grandma Rhonda) is still partially preserved at the southern margin of the study basin. Around 9.0 cal ka BP a shallow and more dynamic thermokarst lake developed with actively eroding shorelines and potentially intermediate shallow water or wetland phases (Mama Rhonda). Mama Rhonda lake drainage at 1.1 cal ka BP was followed by gradual accumulation of terrestrial peat and top-down refreezing of the lake talik. A significant lower organic carbon content was measured in Grandma Rhonda deposits (mean TOC of 2.5 wt%) than in Mama Rhonda deposits (mean TOC of 7.9 wt%) highlighting the impact of thermokarst dynamics on biogeochemical cycling in different lake generations by thawing and mobilization of organic carbon into the lake system.
Proximal and distal sediment cores from Peatball Lake on the Arctic Coastal Plain of Alaska revealed young thermokarst dynamics since about 1,400 years along a depositional gradient based on reconstructions from shoreline expansion rates and absolute dating results. After its initiation as a remnant pond of a previous drained lake basin, a rapidly deepening lake with increasing oxygenation of the water column is evident from laminated sediments, and higher Fe/Ti and Fe/S ratios in the sediment. The sediment record archived characterizing shifts in depositional regimes and sediment sources from upland deposits and re-deposited sediments from drained thaw lake basins depending on the gradually changing shoreline configuration. These changes are evident from alternating organic inputs into the lake system which highlights the potential for thermokarst lakes to recycle old carbon from degrading permafrost deposits of its catchment.
The lake sediment record from Herschel Island in the Yukon (Canada) covers the full Holocene period. After its initiation as a thermokarst lake at 11.7 cal ka BP and intense thermokarst activity until 10.0 cal ka BP, the steady sedimentation was interrupted by a depositional hiatus at 1.6 cal ka BP which likely resulted from lake drainage or allochthonous slumping due to collapsing shore lines. The specific setting of the lake on a push moraine composed of marine deposits is reflected in the sedimentary record. Freshening of the maturing lake is indicated by decreasing electrical conductivity in pore-water. Alternation of marine to freshwater ostracods and foraminifera confirms decreasing salinity as well but also reflects episodical re-deposition of allochthonous marine sediments.
Based on permafrost and lacustrine sediment records, this thesis shows examples of the Late Quaternary evolution of typical Arctic permafrost landscapes in central-eastern Beringia and the complex interaction of local disturbance processes, regional environmental dynamics and global climate patterns. This study confirms that thermokarst lakes are important agents of organic matter recycling in complex and continuously changing landscapes.
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.
Block copolypeptoids comprising a thermosensitive, crystallizable poly(N-(n-propyl)glycine) block and a watersoluble poly(N-methylglycine) block, P70My (y = 23, 42, 76, 153, and 290), were synthesized bY ring-opening polymerization of the corresponding N-alkylglycine N-carboxyanhydrides (NCAs) and examined according to their thermo-induced aggregation and crystallization in water by turbidimetty, micro-differential scanning calorimetry (micro-DSC); cryogenic scanning electron microscopy (cryo-SEM), analytical ultracentrifugation (AUC), and static light scattering (SLS). At a temperature above the cloud point temperature, the initially formed micellar aggregates started to crystallize and grow into larger complex assemblies of about 100-500 nm, exhibiting flower-like (P70M23), ellipsoidal (P70M42 and P70M72) or irregular shapes (P70M153 and.P70M290).
The influence of the temperature in the gas-filled cavities on the charging process of ferroelectret film systems has been studied in hysteresis measurements. The threshold voltage and the effective polarization of the ferroelectrets were determined as functions of the charging temperature TP. With increasing TP, the threshold voltage for triggering dielectric barrier discharges in ferroelectrets decreases. Thus, increasing the temperature facilitates the charging of ferroelectrets. However, a lower threshold voltage reduces the attainable remanent polarization because back discharges occur at lower charge levels, as soon as the charging voltage is turned off. The results are discussed in view of Paschen's law for electrical breakdown, taking into account the respective gas temperature and a simplified model for ferroelectrets. Our results indicate that the thermal poling scheme widely used for conventional ferroelectrics is also useful for electrically charging ferroelectrets.
Ferroelectrets (sometimes also called piezoelectrets) are relatively new members of the family of piezo-, pyro-, and ferroelectric materials.1–5 As their name indicates, ferroelectrets are space-charge electrets that show ferroic behavior. They are non-uniform electret materials or materials systems with electrically charged internal cavities. As space-charge electrets, ferroelectrets usually do not contain any molecular dipoles. However, the cavities inside the material can be turned into macroscopic dipoles through a series of micro-plasma discharges at high electric fields, so-called dielectric barrier discharges (DBDs).6–8 The gas inside the cavities is ionized when the internal electric field exceeds the threshold for electrical breakdown, generating charges of both polarities.9 The positive and negative charges travel in opposite directions, and are eventually trapped at the internal top and bottom surfaces of the cavities, respectively. After charging, the cavities may be regarded as macroscopic dipoles that can be switched by reversing the applied voltage.
An electric-polarization-vs.-electric-field (P(E)) hysteresis is considered as an essential criterion for ferroelectricity. P(E)-hysteresis curves are usually characterized by the spontaneous polarization, the coercive field, and the remanent polarization. Recently, we have demonstrated P(E)-hysteresis loops on two different types of ferroelectrets, namely, cellular polypropylene ferroelectrets and tubular-channel fluoroethylene-polypropylene copolymer ferroelectrets.10,11 The P(E)-hysteresis loops not only prove the ferroic behavior of ferroelectrets, but also allow us to determine such parameters as the coercive field and the remanent polarization.
It is widely accepted that Paschen breakdown is the underlying mechanism for the inception of DBDs in ferroelectrets.12–14 On this basis, the charging behavior and the resulting piezoelectricity of ferroelectrets in different gases at various pressures have been studied.15–17 Paschen's law describes the conditions for electrical breakdown in a gas at a constant temperature (usually room temperature), and it needs to be modified for gas breakdown at other temperatures. The temperature stability of the piezoelectricity in ferroelectrets after charging at elevated temperatures was investigated by several researchers.18–21 Recently, a preliminary report about the effects of the charging temperature on the hysteresis loops in ferroelectrets has been presented.22
In this letter, the influence of the gas temperature on the charging of ferroelectret systems is investigated in more detail by means of quasi-ferroelectric hysteresis-loop measurements. Teflon™ fluoroethylenepropylene (FEP) copolymer samples with tubular channels were prepared via thermal lamination as described previously.23 To this end, two FEP films with a thickness of 50 μm each were laminated at 300 ° C
around a 100 μm thick polytetrafluoroethylene (PTFE) template (total area 35 mm × 45 mm) that contains parallel rectangular openings (area 1.5 mm × 40 mm each). After lamination, the template was removed, which results in an FEP film system with open tubular channels. The samples were metallized on both surfaces with aluminum electrodes of 20 mm diameter.
P(E)-hysteresis loops were obtained with a modified Sawyer–Tower (ST) circuit.10,11 A high-voltage (HV) capacitor C1 (3 nF) and a large standard capacitor Cm (1 μF) were connected in series with the sample. A bipolar sinusoidal voltage with a frequency of 10 mHz was applied from an HV power supply (FUG HCB 7-6500) controlled by an arbitrary-waveform generator (HP 33120a). The voltage Vout
on Cm is measured by means of an electrometer (HP 3458a), and the charge flowing through the circuit is determined as Q(t)=CmVout(t)
. The experiments were carried out at isothermal conditions in a Novocontrol® Quatro cryosystem.
With the modified ST circuit, Q–V loops have been measured on a tubular-channel FEP ferroelectret system at different temperatures. The sample capacitance of about 34.5 pF is determined by a linear fit of the initial part of the Q–V curve recorded at 20 °C
, where the voltage has been raised up from zero on a fresh sample. The hysteresis loops are obtained from the Q–V curves by subtracting the contribution that results from charging of the sample capacitance.10 Figure 1 shows the hysteresis loops of the sample at −100, 0, and +100 ° C, respectively. According to previous theoretical and experimental studies,24,25 the length of each of the horizontal sides of the parallelogram-like hysteresis loops is given by 2Vth where Vth is the threshold voltage. As the charging temperature decreases, the hysteresis loop becomes wider and less high, i.e., the threshold voltage increases, while the polarization at maximum voltage decreases.
The "VISTA near-infrared YJK(s) survey of the Magellanic Clouds System" (VMC) is collecting deep K-s-band time-series photometry of pulsating variable stars hosted by the two Magellanic Clouds and their connecting Bridge. In this paper, we present Y, J, K-s light curves for a sample of 4172 Small Magellanic Cloud (SMC) Classical Cepheids (CCs). These data, complemented with literature V values, allowed us to construct a variety of period-luminosity (PL), period-luminosity-color (PLC), and period-Wesenheit (PW) relationships, which are valid for Fundamental (F), First Overtone (FO), and Second Overtone (SO) pulsators. The relations involving the V, J, K-s bands are in agreement with their counterparts in the literature. As for the Y band, to our knowledge, we present the first CC PL, PW, and PLC relations ever derived using this filter. We also present the first near-infrared PL, PW, and PLC relations for SO pulsators to date. We used PW(V, K-s) to estimate the relative SMC-LMC distance and, in turn, the absolute distance to the SMC. For the former quantity, we find a value of Delta mu = 0.55. +/- 0.04 mag, which is in rather good agreement with other evaluations based on CCs, but significantly larger than the results obtained from older population II distance indicators. This discrepancy might be due to the different geometric distributions of young and old tracers in both Clouds. As for the absolute distance to the SMC, our best estimates are mu(SMC) = 19.01 +/- 0.05 mag and mu(SMC) = 19.04 +/- 0.06 mag, based on two distance measurements to the LMC which rely on accurate CC and eclipsing Cepheid binary data, respectively.
We present K-s-band light curves for 299 Cepheids in the Small Magellanic Cloud (SMC) of which 288 are new discoveries that we have identified using multi-epoch near-infrared photometry obtained by the VISTA survey of the Magellanic Clouds system (VMC). The new Cepheids have periods in the range from 0.34 to 9.1 d and cover the magnitude interval 12.9 <= currency sign < K-s > <= currency sign 17.6 mag. Our method was developed using variable stars previously identified by the optical microlensing survey OGLE. We focus on searching new Cepheids in external regions of the SMC for which complete VMC K-s-band observations are available and no comprehensive identification of different types of variable stars from other surveys exists yet.
The reservoir competence and long life expectancy of edible dormice, Glis glis, suggest that they serve as efficient reservoir hosts for Lyme disease (LD) spirochetes. Their arboreality, however, may reduce the probability to encounter sufficient questing Ixodes ricinus ticks to acquire and perpetuate LD spirochetes. To define the potential role of this small arboreal hibernator in the transmission cycle of LD spirochetes, we examined their rate and density of infestation with subadult ticks throughout the season of activity. Of the 1081 edible dormice that we captured at five study sites in Southern Germany and inspected for ticks at 2946 capture occasions, 26 % were infested with at least one and as many as 26 subadult ticks on their ear pinnae. The distribution of ticks feeding on edible dormice was highly aggregated. Although only few individuals harbored nymphal ticks soon after their emergence from hibernation, the rate of nymphal infestation increased steadily throughout the season and reached about 35 % in September. Dormice inhabiting a site with few conspecifics seemed more likely to be infested by numerous ticks, particularly nymphs, than those individuals living in densely populated sites. Male dormice were more likely to be parasitized by numerous nymphs than were females, independent of their age and body mass. Our observation that season, population density, and sex affect the rates of ticks feeding on edible dormice suggests that the contribution of edible dormice to the transmission cycle of LD spirochetes depends mainly on their ranging behavior and level of activity.
Crowdsourcing platforms provide an affordable approach for recruiting large and diverse samples in a short time. Past research has shown that researchers can obtain reliable data from these sources, at least in domains of research that are not affectively involving. The goal of the present study was to test if crowdsourcing platforms can also be used to conduct experiments that incorporate the induction of aversive affective states. First, a laboratory experiment with German university students was conducted in which a frustrating task induced anger and aggressive behavior. This experiment was then replicated online using five crowdsourcing samples. The results suggest that participants in the online samples reacted very similarly to the anger manipulation as participants in the laboratory experiments. However, effect sizes were smaller in crowdsourcing samples with non-German participants while a crowdsourcing sample with exclusively German participants yielded virtually the same effect size as in the laboratory.
White adipose tissue (WAT) is actively involved in the regulation of whole-body energy homeostasis via storage/ release of lipids and adipokine secretion. Current research links WAT dysfunction to the development of metabolic syndrome (MetS) and type 2 diabetes (T2D). The expansion of WAT during oversupply of nutrients prevents ectopic fat accumulation and requires proper preadipocyte-to-adipocyte differentiation. An assumed link between excess levels of reactive oxygen species (ROS), WAT dysfunction and T2D has been discussed controversially. While oxidative stress conditions have conclusively been detected in WAT of T2D patients and related animal models, clinical trials with antioxidants failed to prevent T2D or to improve glucose homeostasis. Furthermore, animal studies yielded inconsistent results regarding the role of oxidative stress in the development of diabetes. Here, we discuss the contribution of ROS to the (patho) physiology of adipocyte function and differentiation, with particular emphasis on sources and nutritional modulators of adipocyte ROS and their functions in signaling mechanisms controlling adipogenesis and functions of mature fat cells. We propose a concept of ROS balance that is required for normal functioning of WAT. We explain how both excessive and diminished levels of ROS, e. g. resulting from over supplementation with antioxidants, contribute to WAT dysfunction and subsequently insulin resistance.
Two visual world eyetracking experiments investigated how acoustic cue value and statistical variance affect perceptual uncertainty during Cantonese consonant (Experiment 1) and tone perception (Experiment 2). Participants heard low- or high-variance acoustic stimuli. Euclidean distance of fixations from target and competitor pictures over time was analysed using Generalised Additive Mixed Modelling. Distance of fixations from target and competitor pictures varied as a function of acoustic cue, providing evidence for gradient, nonlinear sensitivity to cue values. Moreover, cue value effects significantly interacted with statistical variance, indicating that the cue distribution directly affects perceptual uncertainty. Interestingly, the time course of effects differed between target distance and competitor distance models. The pattern of effects over time suggests a global strategy in response to the level of uncertainty: as uncertainty increases, verification looks increase accordingly. Low variance generally creates less uncertainty, but can lead to greater uncertainty in the face of unexpected speech tokens. (C) 2016 Elsevier Inc. All rights reserved.
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.
In this study we investigated conditions for loss of GPS signals observed by the Swarm satellites during a 2 year period, from December 2013 to November 2015. Our result shows that the Swarm satellites encountered most of the total loss of GPS signal at the ionization anomaly crests, between +/- 5 degrees and +/- 20 degrees magnetic latitude, forming two bands along the magnetic equator, and these low-latitude events mainly appear around postsunset hours from 19: 00 to 22: 00 local time. By further checking the in situ electron density measurements of Swarm, we found that practically, all the total loss of GPS signal events at low latitudes are related to equatorial plasma irregularities (EPIs) that show absolute density depletions larger than 10 x 10(11) m(-3); then, the Swarm satellites encountered for up to 95% loss of GPS signal for at least one channel and up to 45% tracked less than four GPS satellites (making precise orbit determination impossible). For those EPIs with density depletions less than 10 x 10(11) m(-3), the chance of tracked GPS signals less than four reduces to only 1.0%. Swarm also observed total loss of all GPS signal at high latitudes, mainly around local noon, and these events are related to large spatial density gradients due to polar patches or increased geomagnetic/auroral activities. We further found that the loss of GPS signals were less frequent after appropriate settings of the Swarm GPS receivers had been updated. However, the more recent period of the mission, e.g., after the GPS receiver settings have been updated, also coincides with less severe electron density depletions due to the declining solar cycle, making GPS loss events less likely. We conclude that both lower electron density gradients and appropriate GPS receiver settings reduce the probability for Swarm satellites loss of GPS signals.
This article introduces the concept of sustainability-rooted anticonsumption (SRAC), which refers to consumers' anticonsumption practices of voluntary simplicity in living and, on a smaller level, collaborative consumption and boycotting with the goal of supporting sustainable economic development. The SRAC measurement approach is validated based on three empirical studies. Results of a representative German sample (Study 2) reveal that SRAC is predominantly negatively linked to consumer overconsumption dispositions. Exemplary, voluntary simplification and boycott intention may result in declining levels of indebtedness. Study 3 shows that psychosocial well-being is positively related to SRAC and overconsumption. However, a simplified lifestyle and a greater willingness to boycott are not necessarily associated with psychosocial well-being. This article provides insights for practitioners and policymakers to leverage existing SRAC values via “new” business models (sharing offers) or to influence the existing level of consciousness to effectively pave the way for solid progress in the sustainability movement.
This article introduces the concept of sustainability-rooted anticonsumption (SRAC), which refers to consumers' anticonsumption practices of voluntary simplicity in living and, on a smaller level, collaborative consumption and boycotting with the goal of supporting sustainable economic development. The SRAC measurement approach is validated based on three empirical studies. Results of a representative German sample (Study 2) reveal that SRAC is predominantly negatively linked to consumer overconsumption dispositions. Exemplary, voluntary simplification and boycott intention may result in declining levels of indebtedness. Study 3 shows that psychosocial well-being is positively related to SRAC and overconsumption. However, a simplified lifestyle and a greater willingness to boycott are not necessarily associated with psychosocial well-being. This article provides insights for practitioners and policymakers to leverage existing SRAC values via “new” business models (sharing offers) or to influence the existing level of consciousness to effectively pave the way for solid progress in the sustainability movement.
Iceland is located on the Mid-Atlantic Ridge which is the plate boundary between the Eurasian and the North American plates. It is one of the few places on earth where an active spreading centre is located onshore but the stress pattern has not been extensively investigated so far. In this paper we present a comprehensive compilation of the orientation of maximum horizontal stress (S-Hmax). In particular we interpret borehole breakouts and drilling induced fractures from borehole image logs in 57 geothermal wells onshore Iceland. The borehole results are combined with other stress indicators including earthquake focal mechanism solutions, geological information and overcoring measurements resulting in a dataset with 495 data records for the S-Hmax orientation. The reliability of each indicator is assessed according to the quality criteria of the World Stress Map project The majority of S-Hmax orientation data records in Iceland is derived from earthquake focal mechanism solutions (35%) and geological fault slip inversions (26%). 20% of the data are borehole related stress indicators. In addition minor shares of S-Hmax orientations are compiled, amongst others, from focal mechanism inversions and the alignment of fissure eruptions. The results show that the S-Hmax orientations derived from different depths and stress indicators are consistent with each other.
The resulting pattern of the present-day stress in Iceland has four distinct subsets of S-Hmax orientations. The S-Hmax orientation is parallel to the rift axes in the vicinity of the active spreading regions. It changes from NE-SW in the South to approximately N-S in central Iceland and NNW-SSE in the North. In the Westfjords which is located far away from the ridge the regional S-Hmax rotates and is parallel to the plate motion. (C) 2016 Elsevier B.V. All rights reserved.
This article is a response to calls in prior research that we need more longitudinal 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 expectations, 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 16 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 membership. 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.
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.
The spring of Nadaouiyeh Ain Askar - Paleoecology of a Paleolithic oasis in arid central Syria
(2016)
The site Nadaouiyeh Aïn Askar, an ancient artesian spring near the village of El Kowm, Central Syria, is an example of long lasting human occupation in a desert environment throughout the Middle and Late Pleistocene. The excavations expose a succession of sedimentary units, containing an artifact assemblage assigned to the Acheulean techno-complex. Unit VI, attributed to the Marine Isotope Stage 13, is rich in ostracod valves and was chosen for the present environmental study. From these sediments Heterocypris salina, H. incongruens, Cyprideis torosa, Ilyocypris cf. bradyi, I. inermis, I. cf. gibba, Darwinula stevensoni, Plesiocypridopsis newtoni, Pseudocandona compressa, Candona cf. neglecta, Pseudocandona sp., Trajancypris sp., Physocypria sp. and Mixtacandona sp. are documented for the first time in the Middle Pleistocene of the arid environment of central Syria. Data from these microfossils as well as geochemical proxies implicate three phases, turning the wetland from a palustrine setting into a spring supplied pond with increasing salinity. The high mineralization of the spring waters enables a discussion about early hominin adaptability to brackish waters as drinking water resources, common within the steppe and desert environments along the “out-of-Africa”—corridor in the eastern Mediterranean.
The physiological functions of sphingolipids in animals have been intensively studied, while less attention has been paid to their roles in plants. Here, we reveal the involvement of sphingolipid delta8 desaturase (SlSLD) in the chilling resistance of tomato (Solanum lycopersicum cv. Micro-Tom). We used the virus-induced gene silencing (VIGS) approach to knock-down SlSLD expression in tomato leaves, and then evaluated chilling resistance. Changes in leaf cell structure under a chilling treatment were observed by transmission electron microscopy. In control plants, SlSLD was highly expressed in the fruit and leaves in response to a chilling treatment. The degree of chilling damage was greater in SlSLD-silenced plants than in control plants, indicating that SlSLD knock-down significantly reduced the chilling resistance of tomato. Compared with control plants, SlSLD-silenced plants showed higher relative electrolytic leakage and malondialdehyde content, and lower superoxide dismutase and peroxidase activities after a chilling treatment. Chilling severely damaged the chloroplasts in SlSLD-silenced plants, resulting in the disruption of chloroplast membranes, swelling of thylakoids, and reduced granal stacking. Together, these results show that SlSLD is crucial for chilling resistance in tomato.
Mountain and upland regions provide a wide range of ecosystem services to residents and visitors. While ecosystem research in mountain regions is on the rise, the linkages between sociocultural benefits and ecological systems remain little explored. Mountainous regions close to urban areas provide numerous benefits to a large number of individuals, suggesting a high social value, particularly for cultural ecosystem services. We explored and compared visitors' valuation of ecosystem services in the Pentland Hills, an upland range close to the city of Edinburgh, Scotland, and urban green spaces within Edinburgh. Based on 715 responses to user surveys in both study areas, we identified intense use and high social value for both areas. Several ecosystem services were perceived as equally important in both areas, including many cultural ecosystem services. Significant differences were revealed in the value of physically using nature, which Pentland Hills users rated more highly than those in the urban green spaces, and of mitigation of pollutants and carbon sequestration, for which the urban green spaces were valued more highly. Major differences were further identified for preferences in future land management, with nature-oriented management preferred by about 57% of the interviewees in the Pentland Hills, compared to 31% in the urban parks. The study highlights the substantial value of upland areas in close vicinity to a city for physically using and experiencing nature, with a strong acceptance of nature conservation.
Human development has far-reaching impacts on the surface of the globe. The transformation of natural land cover occurs in different forms, and urban growth is one of the most eminent transformative processes. We analyze global land cover data and extract cities as defined by maximally connected urban clusters. The analysis of the city size distribution for all cities on the globe confirms Zipf’s law. Moreover, by investigating the percolation properties of the clustering of urban areas we assess the closeness to criticality for various countries. At the critical thresholds, the urban land cover of the countries undergoes a transition from separated clusters to a gigantic component on the country scale. We study the Zipf-exponents as a function of the closeness to percolation and find a systematic dependence, which could be the reason for deviating exponents reported in the literature. Moreover, we investigate the average size of the clusters as a function of the proximity to percolation and find country specific behavior. By relating the standard deviation and the average of cluster sizes—analogous to Taylor’s law—we suggest an alternative way to identify the percolation transition. We calculate spatial correlations of the urban land cover and find long-range correlations. Finally, by relating the areas of cities with population figures we address the global aspect of the allometry of cities, finding an exponent δ ≈ 0.85, i.e., large cities have lower densities.
The scaling behavior of rainfall has been extensively studied both in terms of event magnitudes and in terms of spatial extents of the events. Different heavy-tailed distributions have been proposed as candidates for both instances, but statistically rigorous treatments are rare. Here we combine the domains of event magnitudes and event area sizes by a spatiotemporal integration of 3-hourly rain rates corresponding to extreme events derived from the quasi-global high-resolution rainfall product Tropical Rainfall Measuring Mission 3B42. A maximum likelihood evaluation reveals that the distribution of spatiotemporally integrated extreme rainfall cluster sizes over the oceans is best described by a truncated power law, calling into question previous statements about scale-free distributions. The observed subpower law behavior of the distribution's tail is evaluated with a simple generative model, which indicates that the exponential truncation of an otherwise scale-free spatiotemporal cluster size distribution over the oceans could be explained by the existence of land masses on the globe.
A broad array of new provenance and stable isotope data are presented from two magnetostratigraphically dated sections in the south-eastern Issyk Kul basin of the Central Kyrgyz Tien Shan. The results presented here are discussed and interpreted for two plausible magnetostratigraphic age models. A combination of zircon U-Pb provenance, paleocurrent and conglomerate clast count analyses is used to determine sediment provenance. This analysis reveals that the first coarse-grained, syntectonic sediments (Dzhety Oguz formation) were sourced from the nearby Terskey Range, supporting previous thermochronology-based estimates of a ca. 25-20 Ma onset of deformation in the range. Climate variations are inferred using carbonate stable isotope (delta O-18 and delta C-13) data from 53 samples collected in the two sections and are compared with the oxygen isotope compositions of modern water from 128 samples. Two key features are identified in the stable isotope data set derived from the sediments: (1) isotope values, in particular delta C-13, decrease between ca. 26.0 and 23.6 or 25.6 and 21.0 Ma, and (2) the scatter of delta O-18 values increased significantly after ca. 22.6 or 16.9 Ma. The first feature is interpreted to reflect progressively wetter conditions. Because this feature slightly post-dates the onset of deformation in the Terskey Range, we suggest that it has been caused by orographically enhanced precipitation, implying that surface uplift accompanied late Cenozoic deformation and rock uplift in the Terskey Range. The increased scatter could reflect variable moisture source or availability caused by global climate change following the onset of Miocene glaciations at ca. 22.6 Ma, or enhanced evaporation during the Mid-Miocene climatic optimum at ca. 17-15 Ma.
Among the bloom-forming and potentially harmful cyanobacteria, the genus Microcystis represents a most diverse taxon, on the genomic as well as on morphological and secondary metabolite levels. Microcystis communities are composed of a variety of diversified strains. The focus of this study lies on potential interactions between Microcystis representatives and the roles of secondary metabolites in these interaction processes.
The role of secondary metabolites functioning as signaling molecules in the investigated interactions is demonstrated exemplary for the prevalent hepatotoxin microcystin. The extracellular and intracellular roles of microcystin are tested in microarray-based transcriptomic approaches. While an extracellular effect of microcystin on Microcystis transcription is confirmed and connected to a specific gene cluster of another secondary metabolite in this study, the intracellularly occurring microcystin is related with several pathways of the primary metabolism. A clear correlation of a microcystin knockout and the SigE-mediated regulation of carbon metabolism is found. According to the acquired transcriptional data, a model is proposed that postulates the regulating effect of microcystin on transcriptional regulators such as the alternative sigma factor SigE, which in return captures an essential role in sugar catabolism and redox-state regulation.
For the purpose of simulating community conditions as found in the field, Microcystis colonies are isolated from the eutrophic lakes near Potsdam, Germany and established as stably growing under laboratory conditions. In co-habitation simulations, the recently isolated field strain FS2 is shown to specifically induce nearly immediate aggregation reactions in the axenic lab strain Microcystis aeruginosa PCC 7806. In transcriptional studies via microarrays, the induced expression program in PCC 7806 after aggregation induction is shown to involve the reorganization of cell envelope structures, a highly altered nutrient uptake balance and the reorientation of the aggregating cells to a heterotrophic carbon utilization, e.g. via glycolysis. These transcriptional changes are discussed as mechanisms of niche adaptation and acclimation in order to prevent competition for resources.
Background The importance of trunk muscle strength (TMS) for physical fitness and athletic performance has been demonstrated by studies reporting significant correlations between those capacities. However, evidence-based knowledge regarding the magnitude of correlations between TMS and proxies of physical fitness and athletic performance as well as potential effects of core strength training (CST) on TMS, physical fitness and athletic performance variables is currently lacking for trained individuals. Objective The aims of this systematic review and meta-analysis were to quantify associations between variables of TMS, physical fitness and athletic performance and effects of CST on these measures in healthy trained individuals. Data Sources PubMed, Web of Science, and SPORTDiscus were systematically screened from January 1984 to March 2015. Study Eligibility Criteria Studies were included that investigated healthy trained individuals aged 16-44 years and tested at least one measure of TMS, muscle strength, muscle power, balance, and/or athletic performance. Results Small-sized relationships of TMS with physical performance measures (-0.05 <= r <= 0.18) were found in 15 correlation studies. Sixteen intervention studies revealed large effects of CST on measures of TMS (SMD = 1.07) but small-to-medium-sized effects on proxies of physical performance (0 <= SMD <= 0.71) compared with no training or regular training only. The methodological quality of CST studies was low (median PEDro score = 4). Conclusions Our findings indicate that TMS plays only a minor role for physical fitness and athletic performance in trained individuals. In fact, CST appears to be an effective means to increase TMS and was associated with only limited gains in physical fitness and athletic performance measures when compared with no or only regular training.
Treatment delivery factors (i.e., therapist adherence, therapist competence, and therapeutic alliance) are considered to be important for cognitive behavioral therapy (CBT) for panic disorder and agoraphobia (PD/AG). In the current study, four independent raters conducted process evaluations based on 168 two-hour videotapes of 84 patients with PD/AG treated with exposure-based CBT. Two raters evaluated patients’ interpersonal behavior in Session 1. Two raters evaluated treatment delivery factors in Session 6, in which therapists provided the rationale for conducting exposure exercises. At the 6-month follow-up, therapists’ adherence (r = 0.54) and therapeutic alliance (r = 0.31) were significant predictors of changes in agoraphobic avoidance behavior; therapist competence was not associated with treatment outcomes. Patients’ interpersonal behavior in Session 1 was a significant predictor of the therapeutic alliance in Session 6 (r = 0.17). The findings demonstrate that treatment delivery factors, particularly therapist adherence, are relevant to the long-term success of CBT for PD/AG.
The competition between charge extraction and nongeminate recombination critically determines the current-voltage characteristics of organic solar cells (OSCs) and their fill factor. As a measure of this competition, several figures of merit (FOMs) have been put forward; however, the impact of space charge effects has been either neglected, or not specifically addressed. Here we revisit recently reported FOMs and discuss the role of space charge effects on the interplay between recombination and extraction. We find that space charge effects are the primary cause for the onset of recombination in so-called non-Langevin systems, which also depends on the slower carrier mobility and recombination coefficient. The conclusions are supported with numerical calculations and experimental results of 25 different donor/acceptor OSCs with different charge transport parameters, active layer thicknesses or composition ratios. The findings represent a conclusive understanding of bimolecular recombination for drift dominated photocurrents and allow one to minimize these losses for given device parameters.
Flood generation at the scale of large river basins is triggered by the interaction of the hydrological pre-conditions and the meteorological event conditions at different spatial and temporal scales. This interaction controls diverse flood generating processes and results in floods varying in magnitude and extent, duration as well as socio-economic consequences. For a process-based understanding of the underlying cause-effect relationships, systematic approaches are required. These approaches have to cover the complete causal flood chain, including the flood triggering meteorological event in combination with the hydrological (pre-)conditions in the catchment, runoff generation, flood routing, possible floodplain inundation and finally flood losses.
In this thesis, a comprehensive probabilistic process-based understanding of the causes and effects of floods is advanced. The spatial and temporal dynamics of flood events as well as the geophysical processes involved in the causal flood chain are revealed and the systematic interconnections within the flood chain are deciphered by means of the classification of their associated causes and effects. This is achieved by investigating the role of the hydrological pre-conditions and the meteorological event conditions with respect to flood occurrence, flood processes and flood characteristics as well as their interconnections at the river basin scale.
Broadening the knowledge about flood triggers, which up to now has been limited to linking large-scale meteorological conditions to flood occurrence, the influence of large-scale pre-event hydrological conditions on flood initiation is investigated. Using the Elbe River basin as an example, a classification of soil moisture, a key variable of pre-event conditions, is developed and a probabilistic link between patterns of soil moisture and flood occurrence is established. The soil moisture classification is applied to continuously simulated soil moisture data which is generated using the semi-distributed conceptual rainfall-runoff model SWIM. Applying successively a principal component analysis and a cluster analysis, days of similar soil moisture patterns are identified in the period November 1951 to October 2003.
The investigation of flood triggers is complemented by including meteorological conditions described by a common weather pattern classification that represents the main modes of atmospheric state variability. The newly developed soil moisture classification thereby provides the basis to study the combined impact of hydrological pre-conditions and large-scale meteorological event conditions on flood occurrence at the river basin scale.
A process-based understanding of flood generation and its associated probabilities is attained by classifying observed flood events into process-based flood types such as snowmelt floods or long-rain floods. Subsequently, the flood types are linked to the soil moisture and weather patterns. Further understanding of the processes is gained by modeling of the complete causal flood chain, incorporating a rainfall-runoff model, a 1D/2D hydrodynamic model and a flood loss model. A reshuffling approach based on weather patterns and the month of their occurrence is developed to generate synthetic data fields of meteorological conditions, which drive the model chain, in order to increase the flood sample size. From the large number of simulated flood events, the impact of hydro-meteorological conditions on various flood characteristics is detected through the analysis of conditional cumulative distribution functions and regression trees.
The results show the existence of catchment-scale soil moisture patterns, which comprise of large-scale seasonal wetting and drying components as well as of smaller-scale variations related to spatially heterogeneous catchment processes. Soil moisture patterns frequently occurring before the onset of floods are identified. In winter, floods are initiated by catchment-wide high soil moisture, whereas in summer the flood-initiating soil moisture patterns are diverse and the soil moisture conditions are less stable in time. The combined study of both soil moisture and weather patterns shows that the flood favoring hydro-meteorological patterns as well as their interactions vary seasonally. In the analysis period, 18 % of the weather patterns only result in a flood in the case of preceding soil saturation. The classification of 82 past events into flood types reveals seasonally varying flood processes that can be linked to hydro-meteorological patterns. For instance, the highest flood potential for long-rain floods is associated with a weather pattern that is often detected in the presence of so-called ‘Vb’ cyclones. Rain-on-snow and snowmelt floods are associated with westerly and north-westerly wind directions. The flood characteristics vary among the flood types and can be reproduced by the applied model chain. In total, 5970 events are simulated. They reproduce the observed event characteristics between September 1957 and August 2002 and provide information on flood losses. A regression tree analysis relates the flood processes of the simulated events to the hydro-meteorological (pre-)event conditions and highlights the fact that flood magnitude is primarily controlled by the meteorological event, whereas flood extent is primarily controlled by the soil moisture conditions.
Describing flood occurrence, processes and characteristics as a function of hydro-meteorological patterns, this thesis is part of a paradigm shift towards a process-based understanding of floods. The results highlight that soil moisture patterns as well as weather patterns are not only beneficial to a probabilistic conception of flood initiation but also provide information on the involved flood processes and the resulting flood characteristics.
Low Earth orbiting geomagnetic satellite missions, such as the Swarm satellite mission, are the only means to monitor and investigate ionospheric currents on a global scale and to make in situ measurements of F region currents. High-precision geomagnetic satellite missions are also able to detect ionospheric currents during quiet-time geomagnetic conditions that only have few nanotesla amplitudes in the magnetic field. An efficient method to isolate the ionospheric signals from satellite magnetic field measurements has been the use of residuals between the observations and predictions from empirical geomagnetic models for other geomagnetic sources, such as the core and lithospheric field or signals from the quiet-time magnetospheric currents. This study aims at highlighting the importance of high-resolution magnetic field models that are able to predict the lithospheric field and that consider the quiet-time magnetosphere for reliably isolating signatures from ionospheric currents during geomagnetically quiet times. The effects on the detection of ionospheric currents arising from neglecting the lithospheric and magnetospheric sources are discussed on the example of four Swarm orbits during very quiet times. The respective orbits show a broad range of typical scenarios, such as strong and weak ionospheric signal (during day- and nighttime, respectively) superimposed over strong and weak lithospheric signals. If predictions from the lithosphere or magnetosphere are not properly considered, the amplitude of the ionospheric currents, such as the midlatitude Sq currents or the equatorial electrojet (EEJ), is modulated by 10–15 % in the examples shown. An analysis from several orbits above the African sector, where the lithospheric field is significant, showed that the peak value of the signatures of the EEJ is in error by 5 % in average when lithospheric contributions are not considered, which is in the range of uncertainties of present empirical models of the EEJ.
Low Earth orbiting geomagnetic satellite missions, such as the Swarm satellite mission, are the only means to monitor and investigate ionospheric currents on a global scale and to make in situ measurements of F region currents. High-precision geomagnetic satellite missions are also able to detect ionospheric currents during quiet-time geomagnetic conditions that only have few nanotesla amplitudes in the magnetic field. An efficient method to isolate the ionospheric signals from satellite magnetic field measurements has been the use of residuals between the observations and predictions from empirical geomagnetic models for other geomagnetic sources, such as the core and lithospheric field or signals from the quiet-time magnetospheric currents. This study aims at highlighting the importance of high-resolution magnetic field models that are able to predict the lithospheric field and that consider the quiet-time magnetosphere for reliably isolating signatures from ionospheric currents during geomagnetically quiet times. The effects on the detection of ionospheric currents arising from neglecting the lithospheric and magnetospheric sources are discussed on the example of four Swarm orbits during very quiet times. The respective orbits show a broad range of typical scenarios, such as strong and weak ionospheric signal (during day- and nighttime, respectively) superimposed over strong and weak lithospheric signals. If predictions from the lithosphere or magnetosphere are not properly considered, the amplitude of the ionospheric currents, such as the midlatitude Sq currents or the equatorial electrojet (EEJ), is modulated by 10-15 % in the examples shown. An analysis from several orbits above the African sector, where the lithospheric field is significant, showed that the peak value of the signatures of the EEJ is in error by 5 % in average when lithospheric contributions are not considered, which is in the range of uncertainties of present empirical models of the EEJ.
Background: Word retrieval in aphasia involves different levels of processinglemma retrieval, grammatical encoding, lexeme retrieval, and phonological encodingbefore articulation can be programmed and executed. Several grammatical, semantic, lexical, and phonological characteristics, such as word class, age of acquisition, imageability, and word frequency influence the degree of success in word retrieval. It is, however, not yet clear how these factors interact. The current study focuses on the retrieval of nouns and verbs in isolation and in sentence context and evaluates the impact of the mentioned factors on the performance of a group of 54 aphasic speakers.Aims: The main aim is to measure the effect of word frequency on the retrieval of nouns and verb by disentangling the influence of word class, age of acquisition, imageability, and lemma and lexeme frequencies on word retrieval in aphasia.Methods & Procedures: Four tests for retrieval of nouns, verbs in isolation, and infinitives and finite verbs were administered to 54 aphasic speakers. The influence of lemma and lexeme frequency, Age of Acquisition on the word retrieval abilities was analysed.Outcomes and Results: Word class, age of acquisition, and imageability play a significant role in the retrieval of nouns and verbs: nouns are easier than verbs; the earlier a word has been learned and the more concrete it is, the easier it is to retrieve. When performance is controlled for these factors, lemma frequency turns out to play a minor role: only in object naming does it affect word retrieval: the higher the lemma frequency of a noun, the easier it is to access. Such an effect does not exist for verbs, neither on an action-naming test, nor when verbs have to be retrieved in sentence context. Lexeme frequency was not found to be a better predictor than lemma frequency in predicting word retrieval in aphasia.Conclusions: Word retrieval in aphasia is influenced by grammatical, semantic, and lexical factors. Word frequency only plays a minor role: it affects the retrieval of nouns, but not of verbs.
This study on analogical reasoning evaluates the impact of fluid intelligence on adaptive changes in neural efficiency over the course of an experiment and specifies the underlying cognitive processes. Grade 10 students (N = 80) solved unfamiliar geometric analogy tasks of varying difficulty. Neural efficiency was measured by the event-related desynchronization (ERD) in the alpha band, an indicator of cortical activity. Neural efficiency was defined as a low amount of cortical activity accompanying high performance during problem-solving. Students solved the tasks faster and more accurately the higher their FI was. Moreover, while high FI led to greater cortical activity in the first half of the experiment, high FI was associated with a neurally more efficient processing (i.e., better performance but same amount of cortical activity) in the second half of the experiment. Performance in difficult tasks improved over the course of the experiment for all students while neural efficiency increased for students with higher but decreased for students with lower fluid intelligence. Based on analyses of the alpha sub-bands, we argue that high fluid intelligence was associated with a stronger investment of attentional resource in the integration of information and the encoding of relations in this unfamiliar task in the first half of the experiment (lower-2 alpha band). Students with lower fluid intelligence seem to adapt their applied strategies over the course of the experiment (i.e., focusing on task-relevant information; lower-1 alpha band). Thus, the initially lower cortical activity and its increase in students with lower fluid intelligence might reflect the overcoming of mental overload that was present in the first half of the experiment. (C) 2016 Elsevier Inc. All rights reserved.
Background: Aggression is a severe behavioral problem that interferes with many developmental challenges individuals face in middle childhood and adolescence. Particularly in the peer and in the academic domain, aggression inhibits the individual from making important learning experiences that are predictive for a healthy transition into adulthood. Furthermore, the resulting developmental deficits have the propensity to feedback and to promote aggression at later developmental stages. The aim of the present PhD thesis was to investigate pathways and processes involved in the etiology of aggression by examining the interrelation between multiple developmental problems in the peer and in the academic domain. More specifically, the relevance of affiliation with deviant peers as a driving mechanism for the development of aggression, factors promoting the affiliation with deviant peers (social rejection; academic failure), and mechanisms by which affiliation with deviant peers leads to aggression (external locus of control) were investigated.
Method: The research questions were addressed by three studies. Three data waves were available for the first study, the second and third study were based on two data waves. The first study specified pathways to antisocial behavior by investigating the temporal interrelation between social rejection, academic failure, and affiliation with deviant peers in a sample of 1,657 male and female children and adolescents aged between 6 and 15 years. The second study examined the role of external control beliefs as a potential mediator in the link between affiliation with deviant peers and aggression in a sample of 1,466 children and adolescents in the age of 9 to 19 years, employing a half-longitudinal design. The third study aimed to expand the findings of Study 1 and Study 2 by examining the differential predictivity of combinations of developmental risks for different functions of aggression, using a sample of 1,479 participants in the age between 9 and 19 years. First, profiles of social rejection, academic failure, and affiliation with deviant peers were identified, using latent profile analysis. Second, prospective pathways between risk-profiles and reactive and proactive aggression were investigated, using latent path analysis.
Results: The first study revealed that antisocial behavior at T1 was associated with social rejection and academic failure at T2. Both mechanisms promoted affiliation with deviant peers at the same data wave, which predicted deviancy at T3. Furthermore, both an indirect pathway via social rejection and affiliation with deviant peers and an indirect pathway via academic failure and affiliation with deviant peers significantly mediated the link between antisocial behavior at the first and the third data wave. Additionally, the proposed pathways generalized across genders and different age groups. The second study yielded that external control beliefs significantly mediated the link between affiliation with deviant peers and aggression, with affiliation with deviant peers at T1 predicting external control beliefs at T2 and external control beliefs at T1 predicting aggressive behavior at T2. Again, the analyses provided no evidence for gender and age specific variations in the proposed pathways. In the third study, three distinct risk groups were identified, made up of a large non-risk group, with low scores on all risk measures, a group characterized by high scores on social rejection (SR group), and a group with the highest scores on measures of affiliation with deviant peers and academic failure (APAF group). Importantly, risk group membership was differentially associated with reactive and proactive aggression. Only membership in the SR group at T1 was associated with the development of reactive aggression at T2 and only membership in the APAF group at T1 predicted proactive aggression at T2. Additionally, proactive aggression at T1 predicted membership in the APAF group at T2, indicating a reciprocal relationship between both constructs.
Conclusion: The results demonstrated that aggression causes severe behavioral deficits in social and academic domains which promote future aggression by increasing individuals’ tendency to affiliate with deviant peers. The stimulation of external control beliefs provides an explanation for deviant peers’ effect on the progression and intensification of aggression. Finally, multiple developmental risks were shown to co-occur within individuals and to be differentially predictive of reactive and proactive aggression. The findings of this doctoral dissertation have possible implications for the conceptualization of prevention and intervention programs aimed to reduce aggression in middle childhood and adolescence.
Buyer-seller negotiations have significant impact on a company’s profitability, which makes practitioners aim at maximizing their performance. One lever for increasing bargaining performance is to pursue a clearly defined aspiration, i.e. one’s most desired outcome. In this context, the author explores the role of such aspirations in the three negotiation phases: preparation, bargaining, and striking a deal. She investigates determinants of aspirations, unintended consequences such as unethical bargaining behavior, and the consequences of overly ambitious aspirations. As a result, she does not only close existing gaps in negotiation research, but also derives valuable implications for practitioners
The interplay of an enzyme with a multiblock copolymer PDLCL containing two segments of different hydrophilicity and degradability is explored in thin films at the air-water interface. The enzymatic degradation was studied in homogenous Langmuir monolayers, which are formed when containing more than 40 wt% oligo(epsilon-caprolactone) (OCL). Enzymatic degradation rates were significantly reduced with increasing content of hydrophobic oligo(omega-pentadecalactone) (OPDL). The apparent deceleration of the enzymatic process is caused by smaller portion of water-soluble degradation fragments formed from degradable OCL fragments. Beside the film degradation, a second competing process occurs after adding lipase from Pseudomonas cepacia into the subphase, namely the enrichment of the lipase molecules in the polymeric monolayer. The incorporation of the lipase into the Langmuir film is experimentally revealed by concurrent surface area enlargement and by Brewster angle microscopy (BAM). Aside from the ability to provide information about the degradation behavior of polymers, the Langmuir monolayer degradation (LMD) approach enables to investigate polymer-enzyme interactions for non-degradable polymers. (C) 2016 Elsevier Ltd. All rights reserved.
The recruitment order of scapular muscles depends on the characteristics of the postural task
(2016)
Previous studies show that the scapular muscle recruitment order could possibly change according to the characteristics of the postural task. We aimed to compare the activation latencies of serratus anterior (SA), upper, middle, and lower trapezius (UT, MT and LT, respectively) between an unpredictable perturbation (sudden arm destabilization) and a predictable task (voluntary arm raise) and, to determine the differences in the muscle recruitment order in each task. The electromyographic signals of 23 participants were recorded while the tasks were performed. All scapular muscles showed earlier onset latency in the voluntary arm raise than in the sudden arm destabilization. No significant differences were observed in the muscle recruitment order for the sudden arm destabilization (p > 0.05). Conversely, for voluntary arm raise the MT, LT SA and anterior deltoid (AD) were activated significantly earlier than the UT (p < 0.001). Scapular muscles present a specific recruitment order during a predictable task: SA was activated prior to the AD and the UT after the AD, in a recruitment order of SA, AD, UT, MT, and LT. While in an unpredictable motor task, all muscles were activated after the destabilization without a specific recruitment order, but rather a simultaneous activation. (C) 2016 Elsevier Ltd. All rights reserved.
The Proteasome Acts as a Hub for Plant Immunity and Is Targeted by Pseudomonas Type III Effectors
(2016)
Recent evidence suggests that the ubiquitin-proteasome system is involved in several aspects of plant immunity and that a range of plant pathogens subvert the ubiquitin-proteasome system to enhance their virulence. Here, we show that proteasome activity is strongly induced during basal defense in Arabidopsis (Arabidopsis thaliana). Mutant lines of the proteasome subunits RPT2a and RPN12a support increased bacterial growth of virulent Pseudomonas syringae pv tomato DC3000 (Pst) and Pseudomonas syringae pv maculicola ES4326. Both proteasome subunits are required for pathogen-associated molecular pattern-triggered immunity responses. Analysis of bacterial growth after a secondary infection of systemic leaves revealed that the establishment of systemic acquired resistance (SAR) is impaired in proteasome mutants, suggesting that the proteasome also plays an important role in defense priming and SAR. In addition, we show that Pst inhibits proteasome activity in a type III secretion-dependent manner. A screen for type III effector proteins from Pst for their ability to interfere with proteasome activity revealed HopM1, HopAO1, HopA1, and HopG1 as putative proteasome inhibitors. Biochemical characterization of HopM1 by mass spectrometry indicates that HopM1 interacts with several E3 ubiquitin ligases and proteasome subunits. This supports the hypothesis that HopM1 associates with the proteasome, leading to its inhibition. Thus, the proteasome is an essential component of pathogen-associated molecular pattern-triggered immunity and SAR, which is targeted by multiple bacterial effectors.
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.
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.
The present study investigates to what extent morphological priming varies across different groups of native speakers of a language. In two masked-priming experiments, we investigate the processing of morphologically complex Turkish words in Turkish heritage speakers raised and living in Germany. Materials and experimental design were based on Kırkıcı and Clahsen’s (2013) study on morphological processing in Turkish native speakers and L2 learners, allowing for direct comparisons between the three groups. Experiment 1 investigated priming effects for morphologically related prime-target pairs. Heritage speakers showed a similar pattern of results as the L1 comparison group, with significant priming effects for prime-target pairs with inflected primes (e.g. ‘sorar-sor’ asks-ask) as well as for prime-target pairs with derived primes (e.g. ‘sağlık-sağ’ health-healthy). In Experiment 2, we measured priming effects for prime-target pairs which were semantically and morphologically unrelated, but only related with regard to orthographic overlap (e.g. ‘devre-dev’ period-giant). Unlike both L1 speakers raised in Turkey and highly proficient L2 learners, heritage speakers also showed significant priming effects in this condition. Our results suggest that heritage speakers differ from both native speakers and L2 learners in that they rely more on (orthographic) surface form properties of the stimulus during early stages of word recognition, at the expense of morphological decomposition.
The use of high-frequency sensors on profiling buoys to investigate physical, chemical, and biological processes in lakes is
increasing rapidly. Profiling buoys with automated winches and sensors that collect high-frequency chlorophyll fluorescence
(ChlF) profiles in 11 lakes in the Global Lake Ecological Observatory Network (GLEON) allowed the study of the vertical
and temporal distribution of ChlF, including the formation of subsurface chlorophyll maxima (SSCM). The effectiveness of 3
methods for sampling phytoplankton distributions in lakes, including (1) manual profiles, (2) single-depth buoys, and (3)
profiling buoys were assessed. High-frequency ChlF surface data and profiles were compared to predictions from the
Plankton Ecology Group (PEG) model. The depth-integrated ChlF dynamics measured by the profiling buoy data revealed a
greater complexity that neither conventional sampling nor the generalized PEG model captured. Conventional sampling
techniques would have missed SSCM in 7 of 11 study lakes. Although surface-only ChlF data underestimated average water
column ChlF, at times by nearly 2-fold in 4 of the lakes, overall there was a remarkable similarity between surface and mean
water column data. Contrary to the PEG model’s proposed negligible role for physical control of phytoplankton during the
growing season, thermal structure and light availability were closely associated with ChlF seasonal depth distribution. Thus,
an extension of the PEG model is proposed, with a new conceptual framework that explicitly includes physical metrics to
better predict SSCM formation in lakes and highlight when profiling buoys are especially informative.
In 2002 Germany adopted an ambitious national sustainability strategy, covering all three sustainability spheres and circling around 21 key indicators. The strategy stands out because of its relative stability over five consecutive government constellations, its high status and increasingly coercive nature. This article analyses the strategy's role in the policy process, focusing on the use and influence of indicators as a central steering tool. Contrasting rationalist and constructivist perspectives on the role of knowledge in policy, two factors, namely the level of consensus about policy goals and the institutional setting of the indicators, are found to explain differences in use and influence both across indicators and over time. Moreover, the study argues that the indicators have been part of a continuous process of ‘structuring’ in which conceptual and instrumental use together help structure the sustainability challenge in such a way that it becomes more manageable for government policy.
In 2002 Germany adopted an ambitious national sustainability strategy, covering all three sustainability spheres and circling around 21 key indicators. The strategy stands out because of its relative stability over five consecutive government constellations, its high status and increasingly coercive nature. This article analyses the strategy's role in the policy process, focusing on the use and influence of indicators as a central steering tool. Contrasting rationalist and constructivist perspectives on the role of knowledge in policy, two factors, namely the level of consensus about policy goals and the institutional setting of the indicators, are found to explain differences in use and influence both across indicators and over time. Moreover, the study argues that the indicators have been part of a continuous process of ‘structuring’ in which conceptual and instrumental use together help structure the sustainability challenge in such a way that it becomes more manageable for government policy.
Acquired tolerance to heat stress is an increased resistance to elevated temperature following a prior exposure to heat. The maintenance of acquired thermotolerance in the absence of intervening stress is called ‘thermomemory’ but the mechanistic basis for this memory is not well defined. Here we show that Arabidopsis HSP21, a plastidial small heat shock protein that rapidly accumulates after heat stress and remains abundant during the thermomemory phase, is a crucial component of thermomemory. Sustained memory requires that HSP21 levels remain high. Through pharmacological interrogation and transcriptome profiling, we show that the plastid-localized metalloprotease FtsH6 regulates HSP21 abundance. Lack of a functional FtsH6 protein promotes HSP21 accumulation during the later stages of thermomemory and increases thermomemory capacity. Our results thus reveal the presence of a plastidial FtsH6–HSP21 control module for thermomemory in plants.
The cytoskeleton is an essential component of living cells. It is composed of different types of protein filaments that form complex, dynamically rearranging, and interconnected networks. The cytoskeleton serves a multitude of cellular functions which further depend on the cell context. In animal cells, the cytoskeleton prominently shapes the cell's mechanical properties and movement. In plant cells, in contrast, the presence of a rigid cell wall as well as their larger sizes highlight the role of the cytoskeleton in long-distance intracellular transport. As it provides the basis for cell growth and biomass production, cytoskeletal transport in plant cells is of direct environmental and economical relevance. However, while knowledge about the molecular details of the cytoskeletal transport is growing rapidly, the organizational principles that shape these processes on a whole-cell level remain elusive.
This thesis is devoted to the following question: How does the complex architecture of the plant cytoskeleton relate to its transport functionality? The answer requires a systems level perspective of plant cytoskeletal structure and transport. To this end, I combined state-of-the-art confocal microscopy, quantitative digital image analysis, and mathematically powerful, intuitively accessible graph-theoretical approaches.
This thesis summarizes five of my publications that shed light on the plant cytoskeleton as a transportation network: (1) I developed network-based frameworks for accurate, automated quantification of cytoskeletal structures, applicable in, e.g., genetic or chemical screens; (2) I showed that the actin cytoskeleton displays properties of efficient transport networks, hinting at its biological design principles; (3) Using multi-objective optimization, I demonstrated that different plant cell types sustain cytoskeletal networks with cell-type specific and near-optimal organization; (4) By investigating actual transport of organelles through the cell, I showed that properties of the actin cytoskeleton are predictive of organelle flow and provided quantitative evidence for a coordination of transport at a cellular level; (5) I devised a robust, optimization-based method to identify individual cytoskeletal filaments from a given network representation, allowing the investigation of single filament properties in the network context. The developed methods were made publicly available as open-source software tools.
Altogether, my findings and proposed frameworks provide quantitative, system-level insights into intracellular transport in living cells. Despite my focus on the plant cytoskeleton, the established combination of experimental and theoretical approaches is readily applicable to different organisms. Despite the necessity of detailed molecular studies, only a complementary, systemic perspective, as presented here, enables both understanding of cytoskeletal function in its evolutionary context as well as its future technological control and utilization.
Generalizing a linear expression over a vector space, we call a term of an arbitrary type tau linear if its every variable occurs only once. Instead of the usual superposition of terms and of the total many-sorted clone of all terms in the case of linear terms, we define the partial many-sorted superposition operation and the partial many-sorted clone that satisfies the superassociative law as weak identity. The extensions of linear hypersubstitutions are weak endomorphisms of this partial clone. For a variety V of one-sorted total algebras of type tau, we define the partial many-sorted linear clone of V as the partial quotient algebra of the partial many-sorted clone of all linear terms by the set of all linear identities of V. We prove then that weak identities of this clone correspond to linear hyperidentities of V.
This book offers a clear, critical, and comprehensive overview of theoretical and experimental work on information structure. Different chapters examine the main theories of information structure in syntax, phonology, and semantics as well as perspectives from psycholinguistics and other relevant fields. Following the editors’ introduction the book is divided into four parts. The first, on theories of and theoretical perspectives on information structure, includes chapters on topic, prosody, and implicature. Part II covers a range of current issues in the field, including focus, quantification, and sign languages, while Part III is concerned with experimental approaches to information structure, including processes involved in its acquisition and comprehension. The final part contains a series of linguistic case studies drawn from a wide variety of the world’s language families
Age of acquisition (AOA) has frequently been shown to influence response times and accuracy rates in word processing and constitutes a meaningful variable in aphasic language processing, while its origin in the language processing system is still under debate. To find out where AOA originates and whether and how it is related to another important psycholinguistic variable, namely semantic typicality (TYP), we studied healthy, elderly controls and semantically impaired individuals using semantic priming. For this purpose, we collected reaction times and accuracy rates as well as event-related potential data in an auditory category-member-verification task. The present results confirm a semantic origin of TYP, but question the same for AOA while favouring its origin at the phonology-semantics interface. The data are further interpreted in consideration of recent theories of ageing. (C) 2016 Elsevier Ltd. All rights reserved.
The origin of ambling horses
(2016)
Horseback riding is the most fundamental use of domestic horses and has had a huge influence on the development of human societies for millennia. Over time, riding techniques and the style of riding improved. Therefore, horses with the ability to perform comfortable gaits (e.g. ambling or pacing), so-called ‘gaited’ horses, have been highly valued by humans, especially for long distance travel. Recently, the causative mutation for gaitedness in horses has been linked to a substitution causing a premature stop codon in the DMRT3 gene (DMRT3_Ser301STOP) [1]. In mice, Dmrt3 is expressed in spinal cord interneurons and plays an important role in the development of limb movement coordination [1]. Genotyping the position in 4396 modern horses from 141 breeds revealed that nowadays the mutated allele is distributed worldwide with an especially high frequency in gaited horses and breeds used for harness racing [2]. Here, we examine historic horse remains for the DMRT3 SNP, tracking the origin of gaitedness to Medieval England between 850 and 900 AD. The presence of the corresponding allele in Icelandic horses (9th–11th century) strongly suggests that ambling horses were brought from the British Isles to Iceland by Norse people. Considering the high frequency of the ambling allele in early Icelandic horses, we believe that Norse settlers selected for this comfortable mode of horse riding soon after arrival. The absence of the allele in samples from continental Europe (including Scandinavia) at this time implies that ambling horses may have spread from Iceland and maybe also the British Isles across the continent at a later date.
BACKGROUND: The etiology of low back pain (LBP), one of the most prevalent and costly diseases of our time, is accepted to be multi-causal, placing functional factors in the focus of research. Thereby, pain models suggest a centrally controlled strategy of trunk stiffening in LBP. However, supporting biomechanical evidence is mostly limited to static measurements during maximum voluntary contractions (MVC), probably influenced by psychological factors in LBP. Alternatively, repeated findings indicate that the neuromuscular efficiency (NME), characterized by the strength-to-activation relationship (SAR), of lower back muscles is impaired in LBP. Therefore, a dynamic SAR protocol, consisting of normalized trunk muscle activation recordings during submaximal loads (SMVC) seems to be relevant. This thesis aimed to investigate the influence of LBP on the NME and activation pattern of trunk muscles during dynamic trunk extensions.
METHODS: The SAR protocol consisted of an initial MVC reference trial (MVC1), followed by SMVCs at 20, 40, 60 and 80% of MVC1 load. An isokinetic trunk dynamometer (Con-Trex TP, ROM: 45° flexion to 10° extension, velocity: 45°/s) and a trunk surface EMG setup (myon, up to 12 leads) was used. Extension torque output [Nm] and muscular activation [V] were assessed in all trials. Finally, another MVC trial was performed (MVC2) for reliability analysis. For SAR evaluation the SMVC trial values were normalized [%MVC1] and compared inter- and intra-individually.
The methodical validity of the approach was tested in an isometric SAR single-case pilot study (S1a: N = 2, female LBP patient vs. healthy male). In addition, the validity of the MVC reference method was verified by comparing different contraction modes (S1b: N = 17, healthy individuals). Next, the isokinetic protocol was validated in terms of content for its applicability to display known physiological differences between sexes in a cross-sectional study (S2: each n = 25 healthy males/females). Finally, the influence of acute pain on NME was investigated longitudinally by comparing N = 8 acute LBP patients with the retest after remission of pain (S3). The SAR analysis focused on normalized agonistic extensor activation and abdominal and synergistic extensor co-activation (t-tests, ANOVA, α = .05) as well as on reliability of MVC1/2 outcomes.
RESULTS: During the methodological validation of the protocol (S1a), the isometric SAR was found to be descriptively different between individuals. Whereas torque output was highest during eccentric MVC, no relevant difference in peak EMG activation was found between contraction modes (S1b). The isokinetic SAR sex comparison (S2), though showing no significant overall effects, revealed higher normalized extensor activation at moderate submaximal loads in females (13 ± 4%), primarily caused by pronounced thoracic activation. Similarly, co-activation analysis resulted in significantly higher antagonistic activation at moderate loads compared to males (33 ± 9%). During intra-individual analysis of SAR in LBP patients (S3), a significant effect of pain status on the SAR has been identified, manifesting as increased normalized EMG activation of extensors during acute LBP (11 ± 8%) particularly at high load. Abdominal co-activation tended to be elevated (27 ± 11%) just as the thoracic extensor parts seemed to take over proportions of lumbar activation. All together, the M. erector spinae behaviour during the SAR protocol was rather linear with the tendency to rise exponentially during high loads. For the level of normalized EMG activation during SMVCs, a clear increasing trend from healthy males to females over to non-acute and acute LBP patients was discovered. This was associated by elevated antagonistic activation and a shift of synergistic towards lumbar extensor activation. The MVC data revealed overall good reliability, with clearly higher variability during acute LBP.
DISCUSSION: The present thesis demonstrates that the NME of lower back muscles is impaired in LBP patients, especially during an acute pain episode. A new dynamic protocol has been developed that makes it possible to display the underlying SAR using normalized trunk muscle EMG during submaximal isokinetic loads. The protocol shows promise as a biomechanical tool for diagnostic analysis of NME in LBP patients and monitoring of rehabilitation progress. Furthermore, reliability not of maximum strength but rather of peak EMG of MVC measurements seems to be decreased in LBP patients. Meanwhile, the findings of this thesis largely substantiate the assumptions made by the recently presented ‘motor adaptation to pain’ model, suggesting a pain-related intra- and intermuscular activation redistribution affecting movement and stiffness of the trunk. Further research is needed to distinguish the grade of NME impairment between LBP subgroups.
When trying to extend the Hodge theory for elliptic complexes on compact closed manifolds to the case of compact manifolds with boundary one is led to a boundary value problem for
the Laplacian of the complex which is usually referred to as Neumann problem. We study the Neumann problem for a larger class of sequences of differential operators on
a compact manifold with boundary. These are sequences of small curvature, i.e., bearing the property that the composition of any two neighbouring operators has order less than two.
The Musical Novel: Imitation of Musical Structure, Performance and Reception in Contemporary Fiction
(2016)
The importance of intraspecific trait variability for community dynamics and ecosystem functioning has been underappreciated. There are theoretical reasons for predicting that species that differ in intraspecific trait variability will also differ in their effects on ecosystem functioning, particularly in variable environments. We discuss whether species with greater trait variability are likely to exhibit greater temporal stability in their population dynamics, and under which conditions this might lead to stability in ecosystem functioning. Resolving this requires us to consider several questions. First, are species with high levels of variation for one trait equally variable in others? In particular, is variability in response and effects traits typically correlated? Second, what is the relative contribution of local adaptation and phenotypic plasticity to trait variability? If local adaptation dominates, then stability in function requires one of two conditions: (i) individuals of appropriate phenotypes present in the environment at high enough frequencies to allow for populations to respond rapidly to the changing environment, and (ii) high levels of dispersal and gene flow. While we currently lack sufficient information on the causes and distribution of variability in functional traits, filling in these key data gaps should increase our ability to predict how changing biodiversity will alter ecosystem functioning.
Formate dehydrogenases (FDHs) are capable of performing the reversible oxidation of formate and are enzymes of great interest for fuel cell applications and for the production of reduced carbon compounds as energy sources from CO2. Metal containing FDHs in general contain a highly conserved active site, comprising a molybdenum (or tungsten) center coordinated by two molybdopterin guanine dinucleotide molecules, a sulfido and a (seleno-)cysteine ligand, in addition to a histidine and arginine residue in the second coordination sphere. So far, the role of these amino acids in catalysis has not been studied in detail, because of the lack of suitable expression systems and the lability or oxygen sensitivity of the enzymes. Here, the roles of these active site residues is revealed using the Mo-containing FDH from Rhodobacter capsulatus. Our results show that the cysteine ligand at the Mo ion is displaced by the formate substrate during the reaction, the arginine has a direct role in substrate binding and stabilization, and the histidine elevates the pK(a) of the active site cysteine. We further found that in addition to reversible formate oxidation, the enzyme is further capable of reducing nitrate to nitrite. We propose a mechanistic scheme that combines both functionalities and provides important insights into the distinct mechanisms of C-H bond cleavage and oxygen atom transfer catalyzed by formate dehydrogenase.
In this Thesis, the properties of aqueous hemicellulose polysaccharides are investigated using computer simulations. The high swelling capacity of materials composed of these molecules allows the generation of directed motion in plant materials entirely controlled by water uptake.
To explore the molecular origin of this swelling capacity, a computational model with atomistic resolution for hemicellulose polysaccharides is build and validated in comparison with experiments. Using this model, simulations of small polysaccharides are employed to gain an understanding of the interactions of these molecules with water, the influence of water on their conformational freedom, and the swelling capacity quantified in terms of osmotic pressure. It is revealed that the branched hemicellulose polysaccharides show different hydration characteristics compared to linear polysaccharides.
To study swelling properties on length and time scales that exceed the limitations imposed by atomistic simulations, a procedure to obtain transferable coarse-grain models is developed. The transferability of the coarse-grain models over both different degrees of polymerization as well as different solute concentrations is demonstrated. Therefore, the procedure allows the construction of large coarse-grained systems based on small atomistic reference systems. Finally, the coarse-grain model is applied to demonstrate that linear and branched polysaccharides show a different swelling behavior when coupled to a water bath.
One hallmark of aging is the accumulation of protein aggregates, promoted by the unfolding of oxidized proteins. Unraveling the mechanism by which oxidized proteins are degraded may provide a basis to delay the early onset of features, such as protein aggregate formation, that contribute to the aging phenotype. In order to prevent aggregation of oxidized proteins, cells recur to the 20S proteasome, an efficient turnover proteolysis complex. It has previously been shown that upon oxidative stress the 26S proteasome, another form, dissociates into the 20S form. A critical player implicated in its dissociation is the Heat Shock Protein 70 (Hsp70), which promotes an increase in free 20S proteasome and, therefore, an increased capability to degrade oxidized proteins. The aim of this study was to test whether or not Hsp70 is involved in cooperating with the 20S proteasome for a selective degradation of oxidatively damaged proteins. Our results demonstrate that Hsp70 expression is induced in HT22 cells as a result of mild oxidative stress conditions. Furthermore, Hsp70 prevents the accumulation of oxidized proteins and directly promotes their degradation by the 20S proteasome. In contrast the expression of the Heat shock cognate protein 70 (Hsc70) was not changed in recovery after oxidative stress and Hsc70 has no influence on the removal of oxidatively damaged proteins. We were able to demonstrate in HT22 cells, in brain homogenates from 129/SV mice and in vitro, that there is an increased interaction of Hsp70 with oxidized proteins, but also with the 20S proteasome, indicating a role of Hsp70 in mediating the interaction of oxidized proteins with the 20S proteasome. Thus, our data clearly implicate an involvement of Hsp70 oxidatively damaged protein degradation by the 20S proteasome. c) 2016 The Authors. Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
The Groningen gas field serves as a natural laboratory for production-induced earthquakes, because no earthquakes were observed before the beginning of gas production. Increasing gas production rates resulted in growing earthquake activity and eventually in the occurrence of the 2012M(w) 3.6 Huizinge earthquake. At least since this event, a detailed seismic hazard and risk assessment including estimation of the maximum earthquake magnitude is considered to be necessary to decide on the future gas production. In this short note, we first apply state-of-the-art methods of mathematical statistics to derive confidence intervals for the maximum possible earthquake magnitude m(max). Second, we calculate the maximum expected magnitude M-T in the time between 2016 and 2024 for three assumed gas-production scenarios. Using broadly accepted physical assumptions and 90% confidence level, we suggest a value of m(max) 4.4, whereas M-T varies between 3.9 and 4.3, depending on the production scenario.
The matrix metalloproteinases (MMP) MMP-2 and MMP-9 are physiological regulators of vascular remodelling. Their dysregulation could contribute to vascular calcification. We examined the role of the MMP-2 and MMP-9 in uraemic vascular calcification in vivo and in vitro. The impact of pharmacological MMP inhibition on the development of media calcifications was explored in an aggressive animal model of uraemic calcification. In addition, the selective effects of addition and inhibition, respectively, of MMP-2 and MMP-9 on calcium-/phosphate-induced calcifications were studied in a murine cell line of vascular smooth muscle cells (VSMCs). High-dose calcitriol treatment of uraemic rats given a high phosphate diet induced massive calcifications, apoptosis and increased gene expressions of MMP-2, MMP-9 and of osteogenic transcription factors and proteins in aortic VSMC. The MMP inhibitor doxycycline prevented the VSMC transdifferentiation to osteoblastic cells, suppressed transcription of mediators of matrix remodelling and almost completely blocked aortic calcifications while further increasing apoptosis. Similarly, specific inhibitors of either MMP-2 or -9, or of both gelatinases (Ro28-2653) and a selective knockdown of MMP-2/-9 mRNA expression blocked calcification of murine VSMC induced by calcification medium (CM). In contrast to MMP inhibition, recombinant MMP-2 or MMP-9 enhanced CM-induced calcifications and the secretion of gelatinases. These data indicate that both gelatinases provide essential signals for phenotypic VSMC conversion, matrix remodelling and the initiation of vascular calcification. Their inhibition seems a promising strategy in the prevention of vascular calcifications.
Large, compressional earthquakes cause surface uplift aswell as widespread mass wasting. Knowledge of their trade-off is fragmentary. Combining a seismologically consistent model of earthquake-triggered landsliding and an analytical solution of coseismic surface displacement, we assess how the mass balance of single earthquakes and earthquake sequences depends on fault size and other geophysical parameters. We find that intermediate size earthquakes (M-w 6-7.3) may cause more erosion than uplift, controlled primarily by seismic source depth and landscape steepness, and less so by fault dip and rake. Such earthquakes can limit topographic growth, but our model indicates that both smaller and larger earthquakes (M-w < 6, M-w > 7.3) systematically cause mountain building. Earthquake sequences with a Gutenberg-Richter distribution have a greater tendency to lead to predominant erosion, than repeating earthquakes of the same magnitude, unless a fault can produce earthquakes with M-w > 8 or more.
The 2014 April 1, M-w 8.1 Iquique (Chile) earthquake struck in the Northern Chile seismic gap. With a rupture length of less than 200 km, it left unbroken large segments of the former gap. Early studies were able to model the main rupture features but results are ambiguous with respect to the role of aseismic slip and left open questions on the remaining hazard at the Northern Chile gap. A striking observation of the 2014 earthquake has been its extensive preparation phase, with more than 1300 events with magnitude above M-L 3, occurring during the 15 months preceding the main shock. Increasing seismicity rates and observed peak magnitudes accompanied the last three weeks before the main shock. Thanks to the large data sets of regional recordings, we assess the precursor activity, compare foreshocks and aftershocks and model rupture preparation and rupture effects. To tackle inversion challenges for moderate events with an asymmetric network geometry, we use full waveforms techniques to locate events, map the seismicity rate and derive source parameters, obtaining moment tensors for more than 300 events (magnitudes M-w 4.0-8.1) in the period 2013 January 1-2014 April 30. This unique data set of fore- and aftershocks is investigated to distinguish rupture process models and models of strain and stress rotation during an earthquake. Results indicate that the spatial distributions of foreshocks delineated the shallower part of the rupture areas of the main shock and its largest aftershock, well matching the spatial extension of the aftershocks cloud. Most moment tensors correspond to almost pure double couple thrust mechanisms, consistent with the slab orientation. Whereas no significant differences are observed among thrust mechanisms in different areas, nor among thrust foreshocks and aftershocks, the early aftershock sequence is characterized by the presence of normal fault mechanisms, striking parallel to the trench but dipping westward. These events likely occurred in the shallow wedge structure close to the slab interface and are consequence of the increased extensional stress in this region after the largest events. The overall stress inversion result suggests a minor stress rotation after the main shock, but a significant release of the deviatoric stress. The temporal change in the distribution of focal mechanisms can also be explained in terms of the spatial heterogeneity of the stress field: under such interpretation, the potential of a large megathrust earthquake breaking a larger segment offshore Northern Chile remains high.
Teacher judgments in terms of grades, proficiency assessments, and recommending placement in ability groups can have important consequences for a child’s future educational path. Whether or not students’ sociodemographic background characteristics are systematically related to teacher judgments has been a controversial topic of discussion. Using data from the TIMSS-Transition Study (N = 3285 fourth graders) administered across 13 German federal states in the 2006–2007 school year and survey data from parents and teachers, we investigated whether or not the average classroom socioeconomic status is reflected in teacher judgments and also examined possible underlying processes. We also probed the role of teachers’ own socioeconomic backgrounds (at the age of 16) in their later susceptibility to differentially judge students from different socioeconomic backgrounds and in differentially composed classrooms. Multilevel regression analyses revealed that, after controlling for differences in achievement (as indicated by standardized tests), teachers’ judgments were associated with the classrooms’ socioeconomic composition, and this finding could not be attributed to the average levels of motivation or behavior in the classroom. Teachers were similarly likely to exhibit such differential judgments regardless of their own socioeconomic background. These findings are discussed in the context of their implications for educational policy.
We analyze the link between R&D, innovation, and productivity in MSMEs with a special focus on micro firms with fewer than 10 employees; usually constituting the majority of firms in industrialized economies. Using the German KfW SME-panel, we examine to what extent micro firms are different from other firms in terms of innovativeness. We find that while firms engage in innovative activities with smaller probability, the smaller they are, for those firms that do make such investment, R&D intensity is larger the smaller firms are. For all MSMEs, the predicted R&D intensity is positively correlated with the probability of reporting innovation, with a larger effect size for product than for process innovations. Moreover, micro firms benefit in a comparable way from innovation processes as larger firms, as they are similarly able to increase their labor productivity. Overall, the link between R&D, innovation, and productivity in micro firms does not largely differ from their larger counterparts. (C) 2016 Elsevier B.V. All rights reserved.