International Max Planck Research School

München, Germany

International Max Planck Research School

München, Germany

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Dallmeyer A.,Max Planck Institute for Meteorology | Claussen M.,Max Planck Institute for Meteorology | Claussen M.,University of Hamburg | Otto J.,International Max Planck Research School
Climate of the Past | Year: 2010

The impact of vegetation-atmosphere and ocean-atmosphere interactions on the mid- to late Holocene climate change as well as their synergy is studied for different parts of the Asian monsoon region, giving consideration to the large climatic and topographical heterogeneity in that area. We concentrate on temperature and precipitation changes as the main parameters describing monsoonal influenced climates. For our purpose, we analyse a set of coupled numerical experiments, performed with the comprehensive Earth system model ECHAM5/JSBACH-MPIOM under present-day and mid-Holocene (6 k) orbital configurations (Otto et al., 2009b). The temperature change caused by the insolation forcing reveals an enhanced seasonal cycle, with a pronounced warming in summer (0.58 K) and autumn (1.29 K) and a cooling in the other seasons (spring: -1.32 K; winter: -0.97 K). Most of this change can be attributed to the direct response of the atmosphere, but the ocean, whose reaction has a lagged seasonal cycle (warming in autumn and winter, cooling in the other seasons), strongly modifies the signal. The simulated contribution of dynamic vegetation is small and most effective in winter, where it slightly warms the near-surface atmosphere (approx. 0.03 K). The temperature difference attributed to the synergy is on average positive, but also small. Concerning the precipitation, the most remarkable change is the postponement and enhancement of the Asian monsoon (0.46 mm/day in summer, 0.53 mm/day in autumn), mainly related to the direct atmospheric response. On regional average, the interactive ocean (ca. 0.18 mm/day) amplifies the direct effect, but tends to weaken the East Asian summer monsoon and strongly increases the Indian summer monsoon rainfall rate (0.68 mm/day). The influence of dynamic vegetation on precipitation is comparatively small (<0.04 mm/day). The synergy effect has no influence, on average. © Author(s) 2010.

Rimac A.,Max Planck Institute for Meteorology | Rimac A.,International Max Planck Research School | Von Storch J.-S.,Max Planck Institute for Meteorology | Eden C.,University of Hamburg | Haak H.,Max Planck Institute for Meteorology
Geophysical Research Letters | Year: 2013

The wind power input to near-inertial (NI) motions is studied using a global eddy-permitting ocean general circulation model. The model is forced by high- (1-hourly, at 0.35° resolution) and low-resolution (6-hourly, at 1.875° resolution) wind data. A change from low- to high-resolution forcing results in an increase in NI kinetic energy by a factor three and raises the wind-generated power input to NI motions from 0.3 TW to 1.1 TW. Time and space filtering of the wind fields yield less kinetic energy, with a larger drop from time filtering. This strong sensitivity to wind forcing points to a possible underestimation of the wind-generated energy available for deep ocean mixing in previous studies based on low-resolution winds. © 2013. American Geophysical Union. All Rights Reserved.

Lee S.,University of Tübingen | Lee S.,International Max Planck Research School | Ruiz S.,University of Tübingen | Ruiz S.,International Max Planck Research School | And 7 more authors.
Neurorehabilitation and Neural Repair | Year: 2011

Background. Studies with real-time functional magnetic resonance imaging (fMRI) demonstrate that humans volitionally regulate hemodynamic signals from circumscribed regions of the brain, leading to area-specific behavioral consequences. Methods to better determine the nature of dynamic functional interactions between different brain regions and plasticity due to self-regulation training are still in development. Objective. The authors investigated changes in brain states while training 6 healthy participants to self-regulate insular cortex by real-time fMRI feedback. Methods. The authors used multivariate pattern analysis to observe spatial pattern changes and a multivariate Granger causality model to show changes in temporal interactions in multiple brain areas over the course of 5 repeated scans per subject during positive and negative emotional imagery with feedback about the level of insular activation. Results. Feedback training leads to more spatially focused recruitment of areas relevant for learning and emotion. Effective connectivity analysis reveals that initial training is associated with an increase in network density; further training "prunes" presumably redundant connections and "strengthens" relevant connections. Conclusions. The authors demonstrate the application of multivariate methods for assessing cerebral reorganization during the learning of volitional control of local brain activity. The findings provide insight into mechanisms of training-induced learning techniques for rehabilitation. The authors anticipate that future studies, specifically designed with this hypothesis in mind, may be able to construct a universal index of cerebral reorganization during skill learning based on multiple similar criteria across various skilled tasks. These techniques may be able to discern recovery from compensation, dose-response curves related to training, and ways to determine whether rehabilitation training is actively engaging necessary networks. © The Author(s) 2011.

Gazi M.A.,International Center for Diarrheal Disease Research | Islam M.R.,International Max Planck Research School | Islam M.R.,University of Bordeaux Segalen | Kibria M.G.,International Center for Diarrheal Disease Research | Mahmud Z.,University of Dhaka
European Journal of Clinical Microbiology and Infectious Diseases | Year: 2015

The global control of tuberculosis remains a great challenge from the standpoint of diagnosis, detection of drug resistance, and treatment, because treatment can only be initiated when infection is detected, and is guided by the results of antimicrobial susceptibility testing. To a large extent, non-molecular, immunological, and other biochemical methods are refinements or modifications of conventional methods, with the primary goal of providing more rapid test results. In contrast, molecular methods use novel technologies to detect the presence of Mycobacterium tuberculosis complex and genes conferring drug resistance. As a group, molecular technologies offer the greatest potential for laboratories in resource-rich countries because they have the highest sensitivity and specificity. In resource-poor settings, continued development of affordable, sensitive, and specific diagnostic tools will be required, where the incidence of disease is highest. © 2015, Springer-Verlag Berlin Heidelberg.

Pavlyuchenkov Y.N.,Russian Academy of Sciences | Wiebe D.S.,Russian Academy of Sciences | Fateeva A.M.,Russian Academy of Sciences | Vasyunina T.S.,Max Planck Institute for Astronomy | Vasyunina T.S.,International Max Planck Research School
Astronomy Reports | Year: 2011

A one-dimensional method for reconstructing the structure of prestellar and protostellar clouds is presented. The method is based on radiative-transfer computations and a comparison of theoretical and observed intensity distributions at both millimeter and infrared wavelengths. The radiative transfer of dust emission is modeled for specified parameters of the density distribution, central star, and external background, and the theoretical distribution of the dust temperature inside the cloud is determined. The intensity distributions at millimeter and IR wavelengths are computed and quantitatively compared with observational data. The best-fit model parameters are determined using a genetic minimization algorithm, which makes it possible to reveal the ranges of parameter degeneracy as well. The method is illustrated by modeling the structure of two infrared dark clouds IRDC-320. 27+029 (P2) and IRDC-321. 73+005 (P2). The derived density and temperature distributions can be used to model the chemical structure and spectral maps in molecular lines. © 2011 Pleiades Publishing, Ltd.

Held M.,Free University of Berlin | Held M.,International Max Planck Research School | Metzner P.,University of Lugano | Metzner P.,Deutsche Forschungsgemeinschaft Research Center | And 4 more authors.
Biophysical Journal | Year: 2011

Protein-ligand interactions are essential for nearly all biological processes, and yet the biophysical mechanism that enables potential binding partners to associate before specific binding occurs remains poorly understood. Fundamental questions include which factors influence the formation of protein-ligand encounter complexes, and whether designated association pathways exist. To address these questions, we developed a computational approach to systematically analyze the complete ensemble of association pathways. Here, we use this approach to study the binding of a phosphate ion to the Escherichia coli phosphate-binding protein. Various mutants of the protein are considered, and their effects on binding freeenergy profiles, association rates, and association pathway distributions are quantified. The results reveal the existence of two anion attractors, i.e., regions that initially attract negatively charged particles and allow them to be efficiently screened for phosphate, which is subsequently specifically bound. Point mutations that affect the charge on these attractors modulate their attraction strength and speed up association to a factor of 10 of the diffusion limit, and thus change the association pathways of the phosphate ligand. It is demonstrated that a phosphate that prebinds to such an attractor neutralizes its attraction effect to the environment, making the simultaneous association of a second phosphate ion unlikely. This study suggests ways in which structural properties can be used to tune molecular association kinetics so as to optimize the efficiency of binding, and highlights the importance of kinetic properties. © 2011 by the Biophysical Society.

Chen C.-Y.,International Max Planck Research School | Chen C.-Y.,Werner Reichardt Center for Integrative Neuroscience | Chen C.-Y.,University of Tübingen | Hafed Z.M.,Werner Reichardt Center for Integrative Neuroscience | Hafed Z.M.,University of Tübingen
Annals of Internal Medicine | Year: 2013

Active sensation poses unique challenges to sensory systems because moving the sensor necessarily alters the input sensory stream. Sensory input quality is additionally compromised if the sensor moves rapidly, as during rapid eye movements, making the period immediately after themovementcritical for recovering reliable sensation. Here,westudied this immediate postmovement interval for the case of microsaccades during fixation, which rapidly jitter the "sensor" exactly when it is being voluntarily stabilized to maintain clear vision. We characterized retinal-image slip in monkeys immediately after microsaccades by analyzing postmovement ocular drifts. We observed enhanced ocular drifts by up to ~28% relative to premicrosaccade levels, and for up to ~50 ms after movement end. Moreover, we used a technique to trigger full-field image motion contingent on real-time microsaccade detection, and we used the initial ocular following response to this motion as a proxy for changes in early visual motion processing caused by microsaccades. When the full-field image motion started during microsaccades, ocular following was strongly suppressed, consistent with detrimental retinal effects of the movements. However, when the motion started after microsaccades, there was up to ~73%increase in ocular following speed, suggesting an enhanced motion sensitivity. These results suggest that the interface between even the smallest possible saccades and "fixation" includes a period of faster than usual image slip, as well as an enhanced responsiveness to image motion, and that both of these phenomena need to be considered when interpreting the pervasive neural and perceptual modulations frequently observed around the time of microsaccades. © 2013 the authors.

De Oliveira T.,TU Munich | De Oliveira T.,International Max Planck Research School | Abiatari I.,TU Munich | Raulefs S.,TU Munich | And 6 more authors.
Molecular Cancer | Year: 2012

Background: We have identified syndecan-2 as a protein potentially involved in perineural invasion of pancreatic adenocarcinoma (PDAC) cells.Methods: Syndecan-2 (SDC-2) expression was analyzed in human normal pancreas, chronic pancreatitis and PDAC tissues. Functional in vitro assays were carried out to determine its role in invasion, migration and signaling.Results: SDC-2 was expressed in the majority of the tested pancreatic cancer cell lines while it was upregulated in nerve-invasive PDAC cell clones. There were 2 distinct expression patterns of SDC-2 in PDAC tissue samples: SDC-2 positivity in the cancer cell cytoplasm and a peritumoral expression. Though SDC-2 silencing (using specific siRNA oligonucleotides) did not affect anchorage-dependent growth, it significantly reduced cell motility and invasiveness in the pancreatic cancer cell lines T3M4 and Su8686. On the transcriptional level, migration-and invasion-associated genes were down-regulated following SDC-2 RNAi. Furthermore, SDC-2 silencing reduced K-ras activity, phosphorylation of Src and - further downstream - phosphorylation of ERK2 while levels of the putative SDC-2 signal transducer p120GAP remained unaltered.Conclusion: SDC-2 is a novel (perineural) invasion-associated gene in PDAC which cooperates with K-ras to induce a more invasive phenotype. © 2012 De Oliveira et al; licensee BioMed Central Ltd.

Koring M.,Free University of Berlin | Koring M.,International Max Planck Research School | Richert J.,Free University of Berlin | Parschau L.,Free University of Berlin | And 3 more authors.
Psychology, Health and Medicine | Year: 2012

Many individuals are motivated to improve their physical activity levels, but often fail to act upon their intention. Interventions fostering volitional strategies, suchas action planning, coping planning, and self-efficacy beliefs, can help to translate intentions into behavior. This study examines the effectiveness and themechanisms of a combined planning and self-efficacy intervention to promote physical activity among motivated individuals. Participants (N = 883) were randomly assigned to the intervention or to a waiting-list control condition. Multivariate analysis of variance revealed that the intervention resulted in significantly more physical activity, higher levels of action planning, coping planning, and volitional self-efficacy beliefs (p < 0.01). In addition, multiple mediation analysis showed that action planning, coping planning, and volitional self-efficacy mediate between the intervention and physical activity. The study shows that the intervention successfully fostered physical activity and unfolds the underlying self-regulatory mechanisms of the intervention's effectiveness. © 2012 Taylor and Francis.

Schultze-Krumbholz A.,Free University of Berlin | Schultze-Krumbholz A.,International Max Planck Research School | Scheithauer H.,Free University of Berlin
International Journal of Developmental Sciences | Year: 2013

Examination of the longitudinal relationship between empathy, social-emotional problems and cyberbullying is still rare and the present study is one of very few. The present study assessed whether low scores of affective and cognitive empathy at wave 1 (t1) can predict involvement in cyberbullying five months later (t2). Furthermore, it was examined whether involvement in cyberbullying at t1 predicts psychopathological symptoms and social withdrawal at t2. Participants were 777th and 8th grade students from a control group of a pre-/posttest short-term longitudinal evaluation study of a general anti-bullying program (mean aget1 = 12.53 years, SD = 0.68; gendert1 = 54.5% boys, 45.5% girls). Separate quasi-poisson regression analyses were conducted and traditional bullying and victimization were included as control variables. Low scores of affective, but not cognitive, empathy predicted cyberbullying but not cybervictimization at t2. Neither cyberbullying nor cybervictimization predicted social withdrawal or psychopathological symptoms at t2 as assessed in this study. The research hypotheses were only partly supported, however, this study using short-term longitudinal data revealed evidence for the importance of (affective) empathy in cyberbullying perpetration. © 2013 - IOS Press and the authors.

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