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A list of rare or interesting phanerogams from Potsdam and surroundings is presented. Most of them were recorded between 2006 and 2008. In some cases short remarks about the taxonomy, distribution and other details are given. The collections of Geranium purpureum and Parietaria judaica are the first records for Brandenburg. The collections of Agastache foeniculum, Coreopsis lanceolata, Geranium nodosum, Hieracium amplexicaule, Juncus ensifolius, Lactuca virosa, Sedum sarmentosum and Verbena bonariensis are probably the first information about adventive occurences of these species in this Federal State. Viscum album is reported on rare host species: Chaenomelis sp., Quercus spp. and Rosa hybrids.
Bemerkenswerte Pilzfunde auf der 38. Brandenburgischen Botanikertagung in Groß Pinnow/Uckermark
(2010)
Der Beitrag geht mit den Texten des Autors Bernd Wagner auf eine Reise, die sowohl unterschiedliche Raeume wie unterschiedliche Zeiten betrifft. Insbesondere die Zeitmauer von Berlin (Ost) nach Berlin (West), die in Wagners Leben einen tiefen Einschnitt hinterliess, zeigt die Dialektik von Diskontinuitaet und Kontinuitaet im Denken und Schreiben Bernd Wagners. Bereits fuer den DDR-Autor Wagner waren Zeitreisen als "Reisen im Kopf" (so auch der Titel seines letzten Bandes in der offiziellen DDR-Literatur) ein schier unerschoepfliches Thema unangepassten Erzaehlens. Es entstanden durch die Erzaehlung Freiraeume, die von der Phantasie erschlossen wurden und die sich ueber die Mauern und Grenzen des tatsaechlichen Lebens hinwegsetzten. Mit der "Wut im Koffer" zeigt der Reisende Wagner auch nach dem Mauerfall, dass sein Reisegepaeck immer griffbereit ist. Ob es ihn nach Chihuahua oder Bali verschlaegt - er bleibt neugierig den eigenen Wegen auf der Spur.
The present study shows that small admixtures of one chlorophyll a (Chla) molecule per several hundred lipid molecules have strong destabilizing effect on lipid bilayers. This effect is clearly displayed in the properties of the L-alpha-H-II transformations and results from a Chla preference for the H-II relative to the L-alpha phase. Chla disfavors the lamellar liquid crystalline phase L-alpha and induces its replacement with inverted hexagonal phase H-II, as is consistently demonstrated by DSC and X-ray diffraction measurements on phosphatidylethanolamine (PE) dispersions. Chla lowers the L-alpha-H-II transition temperature (42 degrees C) of the fully hydrated dipalmitoleoyl PE (DPoPE) by similar to 8 degrees C and similar to 17 degrees C at Chla/DPoPE molar ratios of 1:500 and 1:100, respectively. Similar Chla effect was recorded also for dielaidoyl PE dispersions. The lowering of the transition temperature and the accompanying significant loss of transition cooperativity reflect the Chla repartitioning and preference for the H-II phase. The reduction of the H-II phase lattice constant in the presence of Chla is an indication that Chla favors v phase formation by decreasing the radius of spontaneous monolayer curvature, and not by filling up the interstitial spaces between the H-II phase cylinders. The observed Chla preference for H-II phase and the substantial bilayer destabilization in the vicinity of a bilayer-to-nonbilayer phase transformation caused by low Chla concentrations can be of interest as a potential regulatory or membrane-damaging factor.
To improve our mechanistic understanding and predictive capacities with respect to climate change effects on the spring phytoplankton bloom in temperate marine systems, we used a process-driven dynamical model to disentangle the impact of potentially relevant factors which are often correlated in the field. The model was based on comprehensive indoor mesocosm experiments run at four temperature and three light regimes. It was driven by time-series of water temperature and irradiance, considered edible and less edible phytoplankton separately, and accounted for density- dependent grazing losses. It successfully reproduced the observed dynamics of well edible phytoplankton in the different temperature and light treatments. Four major factors influenced spring phytoplankton dynamics: temperature, light (cloudiness), grazing, and the success of overwintering phyto- and zooplankton providing the starting biomasses for spring growth. Our study predicts that increasing cloudiness as anticipated for warmer winters for the Baltic Sea region will retard phytoplankton net growth and reduce peak heights. Light had a strong direct effect in contrast to temperature. However, edible phytoplankton was indirectly strongly temperature-sensitive via grazing which was already important in early spring at moderately high algal biomasses and counter-intuitively provoked lower and later algal peaks at higher temperatures. Initial phyto- and zooplankton composition and biomass also had a strong effect on spring algal dynamics indicating a memory effect via the broadly under-sampled overwintering plankton community. Unexpectedly, increased initial phytoplankton biomass did not necessarily lead to earlier or higher spring blooms since the effect was counteracted by subsequently enhanced grazing. Increasing temperature will likely exhibit complex indirect effects via changes in overwintering phytoplankton and grazer biomasses and current grazing pressure. Additionally, effects on the phytoplankton composition due to the species-specific susceptibility to grazing are expected. Hence, we need to consider not only direct but also indirect effects, e.g. biotic interactions, when addressing climate change impacts.
Bottom-up effects of plant diversity on multitrophic interactions in a biodiversity experiment
(2010)
Brandenburg
(2010)
Bulk electron transport and charge injection in a high mobility n-type semiconducting polymer
(2010)
Bulk electron transport in a high mobility n-type polymer is studied by time-of-flight photocurrent measurements and electron-only devices. Bulk electron mobilities of similar to 5 x 10(-3) cm(2)/Vs are obtained. The analysis of the electron currents suggests the presence of an injection barrier for all conventionally used low workfunction cathodes.
Calcineurin activity augments cAMP/PKA-dependent activation of V-ATPase in blowfly salivary glands
(2010)
We have examined the role of the Ca2+-dependent protein phosphatase 2B (calcineurin) in the regulation of the vacuolar H+-ATPase (V-ATPase) in blowfly salivary glands. In response to the neurohormone serotonin [5-hydroxytryptamine (5-HT)] and under the mediation of the cAMP/PKA signaling pathway, the secretory cells assemble and activate V-ATPase molecules at the apical membrane. We demonstrate that the inhibition of calcineurin activity by cyclosporin A, by FK- 506, or by prevention of the elevation of Ca2+ diminishes the 5-HT-induced assembly and activation of V-ATPase. The effect of calcineurin on V-ATPase is mediated by the cAMP/PKA signaling pathway, with calcineurin acting upstream of PKA, because 1) cyclosporin A does not influence the 8-(4-chlorophenylthio) adenosine-3',5'-cyclic monophosphate (8-CPT-cAMP)-induced activation of V-ATPase, and 2) the 5-HT-induced rise in cAMP is highly reduced in the presence of cyclosporin A. Moreover, a Ca2+ rise evoked by the sarco(endo) plasmic reticulum Ca2+-ATPase (SERCA) inhibitor cyclopiazonic acid leads to an increase in intracellular cAMP concentration and a calcineurin-mediated PKA- dependent activation of V-ATPase. We propose that calcineurin activity mediates cross talk between the inositol 1,4,5- trisphosphate/Ca2+ and the cAMP/PKA signaling pathways, thereby augmenting the 5-HT-induced rise in cAMP and thus the cAMP/PKA-mediated activation of V-ATPase.
Campos, vivencias y convivencias : Emma Kann, Jorge Semprn y las literaturas sin residencia fija
(2010)
In this article, five cases of odontogenous dysfunctions and musculoskeletal complaints are presented. A common finding in all patients of this study was that the presence of joint complaints was related to deficits in the corresponding muscular function. These deficits were determined by manual muscle tests as described by Kendall et al. [Muscles - Testing and Function, ed 4. Baltimore, Williams and Wilkins, 1993] and were eliminated immediately by a neural therapeutic test injection into the disturbed dental region. The therapy provided solely aimed to eliminate the odontogenous dysfunction. No other therapeutic measures were carried out with regard to the patients' respective muscle, tendon, or joint complaints.
TSPs (tailspike proteins) are essential infection organelles of bacteriophage P22. Upon infection, P22TSP binds to and cleaves the O-antigen moiety of the LPS (lipopolysaccharide) of its Salmonella host To elucidate the role of TSP during infection, we have studied binding to oligosaccharides and polysaccharides of Salmonella enteric Typhimurium and Enteritidis in vitro. P22TSP is a trimeric beta-helical protein with a carbohydrate-binding site on each subunit. Octasaccharide O-antigen fragments bind to P22TSP with micromolar dissociation constants. Moreover, P22TSP is an endorhamnosidase and cleaves the host O-antigen. Catalytic residues lie at the periphery of the high-affinity binding site, which enables unproductive binding modes, resulting in slow hydrolysis. However, the role of this hydrolysis function during infection remains unclear. Binding of polysaccharide to P22TSP is of high avidity with slow dissociation rates when compared with oligosaccharides. In vivo, the infection of Salmonella with phage P22 can be completely inhibited by the addition of LPS, indicating that binding of phage to its host via TSP is an essential step for infection.
Adipogenesis is governed by a well-documented cascade of transcription factors. However, less is known about non-transcription factors that govern early stages of adipogenesis. Here we show that cellular retinol-binding protein type I (CRBP-I), a small cytosolic binding protein for retinol and retinaldehyde, is specifically restricted to preadipocytes in white adipose tissue. The absence of CRBP-I in mice (CRBP-I-KO mice) leads to increased adiposity. Despite increased adiposity, CRBP-I-KO mice remain more glucose tolerant and insulin sensitive during high-fat-diet feeding. 3T3-L1 cells deficient in CRBP-I or mouse embryonic fibroblasts derived from CRBP-I-KO mice had increased adipocyte differentiation and triglyceride (TG) accumulation. This was due to increased expression and activity of PPAR gamma, while other transcription factor pathways in early and late differentiation remained unchanged. Conversely, the overexpression of CRBP-I in 3T3-L1 cells results in decreased TG accumulation. In conclusion, CRBP-I is a cytosolic protein specifically expressed in preadipocytes that regulates adipocyte differentiation in part by affecting PPAR gamma activity.
A large number and wide variety of lake ecosystem models have been developed and published during the past four decades. We identify two challenges for making further progress in this field. One such challenge is to avoid developing more models largely following the concept of others ('reinventing the wheel'). The other challenge is to avoid focusing on only one type of model, while ignoring new and diverse approaches that have become available ('having tunnel vision'). In this paper, we aim at improving the awareness of existing models and knowledge of concurrent approaches in lake ecosystem modelling, without covering all possible model tools and avenues. First, we present a broad variety of modelling approaches. To illustrate these approaches, we give brief descriptions of rather arbitrarily selected sets of specific models. We deal with static models (steady state and regression models), complex dynamic models (CAEDYM, CE-QUAL-W2, Delft 3D-ECO, LakeMab, LakeWeb, MyLake, PCLake, PROTECH, SALMO), structurally dynamic models and minimal dynamic models. We also discuss a group of approaches that could all be classified as individual based: super-individual models (Piscator, Charisma), physiologically structured models, stage-structured models and traitbased models. We briefly mention genetic algorithms, neural networks, Kalman filters and fuzzy logic. Thereafter, we zoom in, as an in-depth example, on the multi-decadal development and application of the lake ecosystem model PCLake and related models (PCLake Metamodel, Lake Shira Model, IPH-TRIM3D-PCLake). In the discussion, we argue that while the historical development of each approach and model is understandable given its 'leading principle', there are many opportunities for combining approaches. We take the point of view that a single 'right' approach does not exist and should not be strived for. Instead, multiple modelling approaches, applied concurrently to a given problem, can help develop an integrative view on the functioning of lake ecosystems. We end with a set of specific recommendations that may be of help in the further development of lake ecosystem models.
In one of the data mining techniques, change-point detection is of importance in evaluating time series measured in real world. For decades this technique has been developed as a nonlinear dynamics. We apply the method for detecting the change points, Singular Spectrum Transformation (SST), to the climate time series. To know where the structures of climate data sets change can reveal a climate background. In this paper we discuss the structures of precipitation data in Kenya and Wrangel Island (Arctic land) by using the SST.
Chanson und Volkslied : Repression und Konkurrenzen einer Gattung im Frankreich des 19. Jahrhunderts
(2010)
We investigate the characteristics of time-delay systems in the presence of Gaussian noise. We show that the delay time embedded in the time series of time-delay system with constant delay cannot be estimated in the presence noise for appropriate values of noise intensity thereby forbidding any possibility of phase space reconstruction. We also demonstrate the existence of complete synchronization between two independent identical time-delay systems driven by a common noise without explicitly establishing any external coupling between them.
New amphiphilic block copolymers consisting of N-vinyl pyrrolidone and vinyl acetate were synthesized via controlled radical polymerization using a reversible addition/fragmentation chain transfer (RAFT)/macromolecular design via the interchange of xanthates (MADIX) system. The synthesis was carried out in 1,4-dioxane as process solvent. In order to get conclusions on the mechanism of the polymerization the molecular structure of formed copolymers was analysed by means of different analytical techniques. C-13 NMR spectroscopy was used for the determination of the monomer ratios. End groups were analysed by means of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. This technique was also used to determine possible fragmentations of the RAFT end groups. By means of a combination of size exclusion chromatography, C-13 NMR and static light scattering molar mass distributions and absolute molar masses could be analysed. The results clearly show a non-ideal RAFT mechanism.
PVP-block-PVAc block copolymers were synthesized by controlled radical polymerization applying a RAFT/MADIX system and were investigated by HPLC and by coupling of chromatography to FT-IR spectroscopy and MALDI-TOF MS. Chromatographic methods (LACCC and gradient techniques) were developed that allowed a separation of block copolymers according to their repeating units. The results of the spectroscopic and spectrometric analysis clearly showed transfer between radicals and process solvent. With the use of hyphenated techniques differences between main and side products were detected. In agreement with previously published results, obtained by NMR, SEC, static light scattering and MALDI- TOF MS, our data proved a non-ideal RAFT polymerization.
Serotonin plays a key role in modulating various physiological and behavioral processes in both protostomes and deuterostomes. The vast majority of serotonin receptors belong to the superfamily of G-protein-coupled receptors. We report the cloning of a cDNA from the honeybee (Am5-ht1A) sharing high similarity with members of the 5-HT1 receptor class. Activation of Am5-HT1A by serotonin inhibited the production of cAMP in a dose-dependent manner (EC50 = 16.9 nM). Am5-HT1A was highly expressed in brain regions known to be involved in visual information processing. Using in vivo pharmacology, we could demonstrate that Am5-HT1A receptor ligands had a strong impact on the phototactic behavior of individual bees. The data presented here mark the first comprehensive study-from gene to behavior-of a 5-HT1A receptor in the honeybee, paving the way for the eventual elucidation of additional roles of this receptor subtype in the physiology and behavior of this social insect.
The method of current extraction under linear increasing voltages (CELIV) allows for the simultaneous determination of charge mobilities and charge densities directly in thin-film geometries as used in organic photovoltaic (OPV) cells. It has been specifically applied to investigate the interrelation of microstructure and charge-transport properties in such systems. Numerical and analytical calculations presented in this work show that the evaluation of CELIV transients with the commonly used analysis scheme is error prone once charge recombination and, possibly, field- dependent charge mobilities are taken into account. The most important effects are an apparent time dependence of charge mobilities and errors in the determined field dependencies. Our results implicate that reports on time-dependent mobility relaxation in OPV materials obtained by the CELIV technique should be carefully revisited and confirmed by other measurement methods.
In terms of the constructivist-orientated sociology of knowledge the social change of Christian religion turns out to be a reconstruction of central forms of knowledge. Mission and Ecumenism are two cornerstones of development This will be demonstrated using, Protestantism as an example. While the recourse on the notion of mission is enabling Christian religion to objectify itself as an integrative world religion against its societal environment, the Ecumenical leitmotif focuses on the denominational fragmented inner relations. Thereby Mission and Ecumenism are not only acting as semantics of,self-description. As distinct knowledge systems they are also standing for a programmatic change of the theological reservoir of knowledge.
Stress is known to induce cigarette craving in smokers, but the underlying mechanisms are widely unknown. We investigated how dependence severity, smoking habits and stress-induced cortisol secretion are associated with increased cigarette craving after a standardised laboratory stressor. Hundred and six healthy participants (50 men, age 18-19 years) underwent a standardised public speaking stress task. In all, 35 smoked daily (DS), 13 smoked occasionally (OS), and 58 never smoked (NS). Smoking was unrestricted until 2 h before stress onset. Plasma cortisol was measured before and up to 95 min after the stressor. All current smokers rated intensity of cigarette craving immediately before and immediately after the stressor using the Brief Questionnaire of Smoking Urges (BQSU). Cortisol levels significantly increased in response to stress in all groups. The magnitude of this stress response was significantly lower in DS compared with OS and NS but did not differ between OS and NS. Baseline BQSU scores were significantly higher in DS than OS. BQSU scores increased significantly during the stress period and were positively correlated to the cortisol response in the DS but were unrelated to their nicotine dependence scores. In OS, no change in cigarette craving could be observed. In daily smokers, cigarette craving is increased after compared with before stress exposure and is related to the magnitude of cortisol stress response rather than to severity of nicotine dependence. This result supports, but does not prove, the concept that hypothalamus-pituitary-adrenal stimulation is one of the mechanisms how stress can elicit cigarette craving.
This study models maximum temperatures in Switzerland monitored in twelve locations using the generalised extreme value (GEV) distribution. The parameters of the GEV distribution are determined within a Bayesian framework. We find that the parameters of the underlying distribution underwent a substantial change in the beginning of the 1980s. This change is characterised by an increase both in the level and the variability. We assess the likelihood of the heat wave of the summer 2003 using the fitted GEV distribution by accounting for the presence of a structural break. The estimation results do suggest that the heat wave of 2003 is not that statistically improbable if an appropriate methodology is used for dealing with nonstationarity.
Physical interactions in quantum many-body systems are typically local: Individual constituents interact mainly with their few nearest neighbors. This locality of interactions is inherited by a decay of correlation functions, but also reflected by scaling laws of a quite profound quantity: the entanglement entropy of ground states. This entropy of the reduced state of a subregion often merely grows like the boundary area of the subregion, and not like its volume, in sharp contrast with an expected extensive behavior. Such "area laws" for the entanglement entropy and related quantities have received considerable attention in recent years. They emerge in several seemingly unrelated fields, in the context of black hole physics, quantum information science, and quantum many-body physics where they have important implications on the numerical simulation of lattice models. In this Colloquium the current status of area laws in these fields is reviewed. Center stage is taken by rigorous results on lattice models in one and higher spatial dimensions. The differences and similarities between bosonic and fermionic models are stressed, area laws are related to the velocity of information propagation in quantum lattice models, and disordered systems, nonequilibrium situations, and topological entanglement entropies are discussed. These questions are considered in classical and quantum systems, in their ground and thermal states, for a variety of correlation measures. A significant proportion is devoted to the clear and quantitative connection between the entanglement content of states and the possibility of their efficient numerical simulation. Matrix-product states, higher-dimensional analogs, and variational sets from entanglement renormalization are also discussed and the paper is concluded by highlighting the implications of area laws on quantifying the effective degrees of freedom that need to be considered in simulations of quantum states.
Shallowly situated evaporites in built-up areas are of relevance for urban and cultural development and hydrological regulation. The hazard of sinkholes, subrosion depressions and gypsum karst is often difficult to evaluate and may quickly change with anthropogenic influence. The geophysical exploration of evaporites in metropolitan areas is often not feasible with active industrial techniques. We collect and combine different passive geophysical data as microgravity, ambient vibrations, deformation and hydrological information to study the roof morphology of shallow evaporites beneath Hamburg, Northern Germany. The application of a novel gravity inversion technique leads to a 3-D depth model of the salt diapir under study. We compare the gravity-based depth model to pseudo-depths from H/V measurements and depth estimates from small-scale seismological array data. While the general range and trend of the diapir roof is consistent, a few anomalous regions are identified where H/V pseudo-depths indicate shallower structures not observed in gravity or array data. These are interpreted by shallow residual caprock floaters and zones of increased porosity. The shallow salt structure clearly correlates with a relative subsidence in the order of 2 mm yr(-1). The combined interpretation of roof morphology, yearly subsidence rates, chemical analyses of groundwater and of hydraulic head in aquifers indicates that the salt diapir beneath Hamburg is subject to significant ongoing dissolution that may possibly affect subrosion depressions, sinkhole distribution and land usage. The combined analysis of passive geophysical data may be exemplary for the study of shallow evaporites beneath other urban areas.
Comparing continuous and discrete birthday coincidences : "Same-Day" versus "Within 24 Hours"
(2010)
In its classical form the famous birthday problem (Feller 1968; Mosteller 1987) addresses coincidences within a discrete sample space, looking at births that fall on the same calendar day. However, coincidence phenomena often arise in situations in which it is more natural to consider a continuous-time parameter. We first describe an elementary variant of the classical problem in continuous time, and then derive and illustrate close approximate relations that exist between the discrete and the continuous formulations.
Objectives: This study investigated the psychological as well as neuroendocrine stress response across one week before an important sport competition, introducing the cortisol awakening response (CAR) to sport psychological research. Methods: On three days in the week before the German Nationals, martial artists (N = 17) reported their competitive state anxiety and collected five samples of salivary cortisol during the first hour after awakening. Results: Hierarchic-linear models and multiple regressions were conducted. Despite a significant rise in "somatic anxiety" (p < .05), the increment of CAR across the week remained non-significant. A moderator function of competitive anxiety on the released amount of cortisol in the morning was not found significant. Results did not show any significant regression of changes in the neuroendocrine response on changes in state anxiety. Conclusion: Non- significant increments of CAR with a closer proximity to the competition may be interpreted as a possible habituation of basal hypothalamus-pituitary-adrenal activity. Moreover, athletes appear to have a lower CAR than found in norm studies, which points to further investigation of interindividual and situational effects on the temporal pattern of the neuroendocrine response to sport competitions.
We consider large populations of phase oscillators with global nonlinear coupling. For identical oscillators such populations are known to demonstrate a transition from completely synchronized state to the state of self-organized quasiperiodicity. In this state phases of all units differ, yet the population is not completely incoherent but produces a nonzero mean field; the frequency of the latter differs from the frequency of individual units. Here we analyze the dynamics of such populations in case of uniformly distributed natural frequencies. We demonstrate numerically and describe theoretically (i) states of complete synchrony, (ii) regimes with coexistence of a synchronous cluster and a drifting subpopulation, and (iii) self-organized quasiperiodic states with nonzero mean field and all oscillators drifting with respect to it. We analyze transitions between different states with the increase of the coupling strength; in particular we show that the mean field arises via a discontinuous transition. For a further illustration we compare the results for the nonlinear model with those for the Kuramoto-Sakaguchi model.
Computational analysis of virtual team collaboration in teh early stages of engineering design
(2010)
Despite many previous Studies on the association between hyperthyroidism and the hyperadrenergic state, controversies still exist. Detrended fluctuation analysis (DFA) is a well recognized method in the nonlinear analysis of heart rate variability (HRV), and it has physiological significance related to the autonomic nervous system. In particular, an increased short-term scaling exponent alpha 1 calculated from DFA is associated with both increased sympathetic activity and decreased vagal activity. No study has investigated the DFA of HRV in hyperthyroidism. This study was designed to assess the sympathovagal balance in hyperthyroidism. We performed the DFA along with the linear analysis of HRV in 36 hyperthyroid Graves' disease patients (32 females and 4 males; age 30 +/- 1 years, means +/- SE) and 36 normal controls matched by sex, age and body mass index. Compared with the normal controls, the hyperthyroid patients revealed a significant increase (P < 0.001) in alpha 1 (hyperthyroid 1.28 +/- 0.04 versus control 0.91 +/- 0.02), long-term scaling exponent alpha 2 (1.05 +/- 0.02 versus 0.90 +/- 0.01), overall scaling exponent alpha (1.11 +/- 0.02 versus 0.89 +/- 0.01), low frequency power in normalized units (LF%) and the ratio of low frequency power to high frequency power (LF/HF); and a significant decrease (P < 0.001) in the standard deviation of the R-R intervals (SDNN) and high frequency power (HF). In conclusion, hyperthyroidism is characterized by concurrent sympathetic activation and vagal withdrawal. This sympathovagal imbalance state in hyperthyroidism helps to explain the higher prevalence of atrial fibrillation and exercise intolerance among hyperthyroid patients.
The first conformational analysis of 3-silathiane and its C-substituted derivatives, namely, 3,3-dimethyl-3- silathiane 1, 2,3,3-trimethyl-3-silathiane 2, and 2-trimethylsilyl-3,3-dimethyl-3-silathiane 3 was performed by using dynamic NMR spectroscopy and B3LYP/6-311G(d,p) quantum chemical calculations. From coalescence temperatures, ring inversion barriers ;G; for 1 and 2 were estimated to be 6.3 and 6.8;kcal/mol, respectively. These values are considerably lower than that of thiacyclohexane (9.4;kcal/mol) but slightly higher than the one of 1,1- dimethylsilacyclohexane (5.5;kcal/mol). The conformational free energy for the methyl group in 2 (;;G°;=;0.35;kcal/mol) derived from low-temperature 13C NMR data is fairly consistent with the calculated value. For compound 2, theoretical calculations give ;E value close to zero for the equilibrium between the 2-Meax and 2-Meeq conformers. The calculated equatorial preference of the trimethylsilyl group in 3 is much more pronounced (;;G°;=;1.8;kcal/mol) and the predominance of the 3-SiMe3 eq conformer at room temperature was confirmed by the simulated 1H NMR and 2D NOESY spectra. The effect of the 2-substituent on the structural parameters of 2 and 3 is discussed.
During hopping an early burst can be observed in the EMG from the soleus muscle starting about 45 ms after touch-down. It may be speculated that this early EMG burst is a stretch reflex response superimposed on activity from a supra-spinal origin. We hypothesised that if a stretch reflex indeed contributes to the early EMG burst, then advancing or delaying the touch-down without the subject's knowledge should similarly advance or delay the burst. This was indeed the case when touch-down was advanced or delayed by shifting the height of a programmable platform up or down between two hops and this resulted in a correspondent shift of the early EMG burst. Our second hypothesis was that the motor cortex contributes to the first EMG burst during hopping. If so, inhibition of the motor cortex would reduce the magnitude of the burst. By applying a low-intensity magnetic stimulus it was possible to inhibit the motor cortex and this resulted in a suppression of the early EMG burst. These results suggest that sensory feedback and descending drive from the motor cortex are integrated to drive the motor neuron pool during the early EMG burst in hopping. Thus, simple reflexes work in concert with higher order structures to produce this repetitive movement.
We consider the suppression of spatiotemporal chaos in the complex Ginzburg-Landau equation by a combined global and local time-delay feedback. Feedback terms are implemented as a control scheme, i.e., they are proportional to the difference between the time-delayed state of the system and its current state. We perform a linear stability analysis of uniform oscillations with respect to space-dependent perturbations and compare with numerical simulations. Similarly, for the fixed-point solution that corresponds to amplitude death in the spatially extended system, a linear stability analysis with respect to space-dependent perturbations is performed and complemented by numerical simulations.
Eye-movement control during scene viewing can be represented as a series of individual decisions about where and when to move the eyes. While substantial behavioral and computational research has been devoted to investigating the placement of fixations in scenes, relatively little is known about the mechanisms that control fixation durations. Here, we propose a computational model (CRISP) that accounts for saccade timing and programming and thus for variations in fixation durations in scene viewing. First, timing signals are modeled as continuous-time random walks. Second, difficulties at the level of visual and cognitive processing can inhibit and thus modulate saccade timing. Inhibition generates moment-by-moment changes in the random walk's transition rate and processing-related saccade cancellation. Third, saccade programming is completed in 2 stages: an initial, labile stage that is subject to cancellation and a subsequent, nonlabile stage. Several simulation studies tested the model's adequacy and generality. An initial simulation study explored the role of cognitive factors in scene viewing by examining how fixation durations differed under different viewing task instructions. Additional simulations investigated the degree to which fixation durations were under direct moment-to-moment control of the current visual scene. The present work further supports the conclusion that fixation durations, to a certain degree, reflect perceptual and cognitive activity in scene viewing. Computational model simulations contribute to an understanding of the underlying processes of gaze control.
Current reversal is an intriguing phenomenon that has been central to recent experimental and theoretical investigations of transport based on ratchet mechanism. By considering a system of two interacting ratchets, we demonstrate how the coupling can be used to control the reversals. In particular, we find that current reversal that exists in a single driven ratchet system can ultimately be eliminated with the presence of a second ratchet. For specific coupling strengths a current-reversal free regime has been detected. Furthermore, in the fully synchronized state characterized by the coupling threshold k(th), a specific driving amplitude a(opt) is found for which the transport is optimum.
We derive local integral and sup-estimates for the curvature of stable marginally outer trapped surfaces in a sliced space-time. The estimates bound the shear of a marginally outer trapped surface in terms of the intrinsic and extrinsic curvature of a slice containing the surface. These estimates are well adapted to situations of physical interest, such as dynamical horizons.
Retinoids are essential in vertebrate reproduction and embryonic development. All-trans-retinoic acid (ATRA) is tightly regulated during these processes. CYP26A1 is mainly responsible for its degradation. To study the role of CYP26A1 during implantation, we applied R115866, a CYP26A1-specific antagonist, to rats during early gestation days (GD). On GD 6.5 and 12 samples were collected and the number of embryos was evaluated. ATRA concentration increased in uterus and serum, mRNA expression of CYP26A1 and CRABP2 increased in the liver, but not in the uterus. Uterine COX1 and 17 beta HSD mRNA expression was decreased. The number of embryos on GD 12 was not altered in this setting. It can be concluded that uterine expression of the analyzed retinoid-response genes during early gestation is not altered by this R115866 treatment and instead indirectly via ATRA. From our experiment we cannot confirm that ATRA obtains a major influencing role in the regulation of embryonic implantation.
Dantes Teufel spricht nicht
(2010)
Das Auswärtige Amt
(2010)
Im "WeltTrends Lehrtext 16" werden wichtige Phasen der Entwicklung des bundesdeutschen Auswärtigen Dienstes dargestellt: Von der Neugründung des Auswärtigen Amtes über dessen Rolle bei der Westintegration der Bundesrepublik Deutschland und bei der Umsetzung der Ostpolitik, bei der Gestaltung des Verhältnisses zwischen den beiden deutschen Staaten bis hin zur Wiedervereinigung. Abschließend werden die umfassenden Reforminitiativen vorgestellt, mit denen der Auswärtige Dienst auf die neuen Herausforderungen dieses Jahrhunderts reagiert.
Das Bundesland
(2010)
Das deutsche Parlament
(2010)
Das Land und die Bezirke
(2010)
Mit dem vorliegenden "WeltTrends Lehrtext 17" wird die "Trilogie zu den auswärtigen deutschen Diensten", die eröffnet wird mit dem "Lehrtext 15" (Deutsche Außenministerien. Der auswärtige Dienst Deutschlands von den Anfängen bis 1945) und ihre Fortsetzung im "Lehrtext 16" (Das Auswärtige Amt. Der auswärtige Dienst der Bundesrepublik Deutschland) findet, komplettiert. Den Abschluss bildet eine weitgefächerte Auseinandersetzung mit der Außenpolitik und Diplomatie der Deutschen Demokratischen Republik: vom Aufbau und der Funktionsweise des außenpolitischen Apparates über das außenpolitische Personal bis zur Abwicklung des Ministeriums für Auswärtige Angelegenheiten.
Objective: The prevalence of unknown impaired fasting glucose (IFG), impaired glucose tolerance (IGT), or type 2 diabetes mellitus (T2DM) is high. Numerous studies demonstrated that IFG, IGT, or T2DM are associated with increased cardiovascular risk, therefore an improved identification strategy would be desirable. The objective of this study was to create a simple and reliable tool to identify individuals with impaired glucose metabolism (IGM). Design and methods: A cohort of 1737 individuals (1055 controls, 682 with previously unknown IGM) was screened by 75 g oral glucose tolerance test (OGTT). Supervised machine learning was used to automatically generate decision trees to identify individuals with IGM. To evaluate the accuracy of identification, a tenfold cross-validation was performed. Resulting trees were subsequently re-evaluated in a second, independent cohort of 1998 individuals (1253 controls, 745 unknown IGM). Results: A clinical decision tree included age and systolic blood pressure (sensitivity 89.3%, specificity 37.4%, and positive predictive value (PPV) 48.0%), while a tree based on clinical and laboratory data included fasting glucose and systolic blood pressure (sensitivity 89.7%, specificity 54.6%, and PPV 56.2%). The inclusion of additional parameters did not improve test quality. The external validation approach confirmed the presented decision trees. Conclusion: We proposed a simple tool to identify individuals with existing IGM. From a practical perspective, fasting blood glucose and blood pressure measurements should be regularly measured in all individuals presenting in outpatient clinics. An OGTT appears to be useful only if the subjects are older than 48 years or show abnormalities in fasting glucose or blood pressure.
Der Einfluss subsilbischer Frequenzen auf die Verbflexion im normalen und gestörten Spracherwerb
(2010)
Ischnopsyllus variabilis (WAGNER, 1898), a model of survival strategy of rare insects? The present paper reports a collection of Ischnopsyllus variabilis in the Schorfheide, a region in the north of Brandenburg (Germany). This bat flea is very rare and the specimens are seldom encountered. The collection of 5 males and 21 females of I. variabilis from summer roosts of the Nathusius`pipistrelle (Pipistrellus nathusii) is a remarkable documentation, since it represents the largest known population of the flea in Europe. Moreover, the data reported here emphasizes for the first time that the Nathusius` pipistrelle is the main host of I. variabilis. The development of the larvae take place in maternity colonies of this bat species. The occurrence of a local concentration of rare specimens may be a vital necessity for the long range survival. Hence, I. variabilis may represent an appropriate model for the understanding of ecology of rare insects, since a local population could be the origin for a scattered distribution over larger areas. The spread of the flea is promoted by the expansive seasonal migrations of the Nathusius`pipistrelle. The exact mechanisms and parameters underlying such an accumulation of specimens in a special maternity colony are still unknown and require further investigations.