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Inferring gene regulatory networks and cellular phases from time-resolved transcriptomics data
(2014)
We study the diffusion of a tracer particle, which moves in continuum space between a lattice of excluded volume, immobile non-inert obstacles. In particular, we analyse how the strength of the tracer–obstacle interactions and the volume occupancy of the crowders alter the diffusive motion of the tracer. From the details of partitioning of the tracer diffusion modes between trapping states when bound to obstacles and bulk diffusion, we examine the degree of localisation of the tracer in the lattice of crowders. We study the properties of the tracer diffusion in terms of the ensemble and time averaged mean squared displacements, the trapping time distributions, the amplitude variation of the time averaged mean squared displacements, and the non-Gaussianity parameter of the diffusing tracer. We conclude that tracer–obstacle adsorption and binding triggers a transient anomalous diffusion. From a very narrow spread of recorded individual time averaged trajectories we exclude continuous type random walk processes as the underlying physical model of the tracer diffusion in our system. For moderate tracer–crowder attraction the motion is found to be fully ergodic, while at stronger attraction strength a transient disparity between ensemble and time averaged mean squared displacements occurs. We also put our results into perspective with findings from experimental single-particle tracking and simulations of the diffusion of tagged tracers in dense crowded suspensions. Our results have implications for the diffusion, transport, and spreading of chemical components in highly crowded environments inside living cells and other structured liquids.
Die Gegenwart der Zukunft
(2015)
Reworking postcolonialism
(2015)
An interdisciplinary collection of essays, Reworking Postcolonialism explores questions of work, precarity, migration, minority and indigenous rights in relation to contemporary globalization. It focuses on the impact of global market forces on the formation of new subject positions among urban dwellers, exiles, and other disenfranchised communities. Bringing together political, economic and literary approaches to texts and events from across the postcolonial world, the essays collected here investigate the transformative effects of the global dissemination of capital and goods and the movements of people. They call for a revision of existing discourses on rights, entitlements and citizenship.
The looping of polymers such as DNA is a fundamental process in the molecular biology of living cells, whose interior is characterised by a high degree of molecular crowding. We here investigate in detail the looping dynamics of flexible polymer chains in the presence of different degrees of crowding. From the analysis of the looping–unlooping rates and the looping probabilities of the chain ends we show that the presence of small crowders typically slows down the chain dynamics but larger crowders may in fact facilitate the looping. We rationalise these non-trivial and often counterintuitive effects of the crowder size on the looping kinetics in terms of an effective solution viscosity and standard excluded volume. It is shown that for small crowders the effect of an increased viscosity dominates, while for big crowders we argue that confinement effects (caging) prevail. The tradeoff between both trends can thus result in the impediment or facilitation of polymer looping, depending on the crowder size. We also examine how the crowding volume fraction, chain length, and the attraction strength of the contact groups of the polymer chain affect the looping kinetics and hairpin formation dynamics. Our results are relevant for DNA looping in the absence and presence of protein mediation, DNA hairpin formation, RNA folding, and the folding of polypeptide chains under biologically relevant high-crowding conditions.
ANG-2 for quantitative Na+ determination in living cells by time-resolved fluorescence microscopy
(2014)
Sodium ions (Na+) play an important role in a plethora of cellular processes, which are complex and partly still unexplored. For the investigation of these processes and quantification of intracellular Na+ concentrations ([Na+]i), two-photon coupled fluorescence lifetime imaging microscopy (2P-FLIM) was performed in the salivary glands of the cockroach Periplaneta americana. For this, the novel Na+-sensitive fluorescent dye Asante NaTRIUM Green-2 (ANG-2) was evaluated, both in vitro and in situ. In this context, absorption coefficients, fluorescence quantum yields and 2P action cross-sections were determined for the first time. ANG-2 was 2P-excitable over a broad spectral range and displayed fluorescence in the visible spectral range. Although the fluorescence decay behaviour of ANG-2 was triexponential in vitro, its analysis indicates a Na+-sensitivity appropriate for recordings in living cells. The Na+-sensitivity was reduced in situ, but the biexponential fluorescence decay behaviour could be successfully analysed in terms of quantitative [Na+]i recordings. Thus, physiological 2P-FLIM measurements revealed a dopamine-induced [Na+]i rise in cockroach salivary gland cells, which was dependent on a Na+-K+-2Cl− cotransporter (NKCC) activity. It was concluded that ANG-2 is a promising new sodium indicator applicable for diverse biological systems.
The in-memory revolution
(2015)
This book describes the next generation of business applications enabled by SAP's in-memory database, SAP HANA. In particular, the authors show the substantial changes introduced in S4/HANA by switching to SAP HANA. Using numerous examples and use cases from the authors' wealth of real-world experience, it illustrates the quantum leap in performance made possible by the new technology. The book is written by two of the most prominent actors in the area of business application systems: Hasso Plattner, co-founder of SAP and inaugurator of the Hasso Plattner Institute at the University of Potsdam, and Bernd Leukert, member of the Executive Board and the Global Managing Board of SAP. This clearly structured, highly illustrated book takes an exciting new technology and presents the practicality and success of first mover applications.
Arsenic-containing hydrocarbons (AsHC) constitute one group of arsenolipids that have been identified in seafood. In this first in vivo toxicity study for AsHCs, we show that AsHCs exert toxic effects in Drosophila melanogaster in a concentration range similar to that of arsenite. In contrast to arsenite, however, AsHCs cause developmental toxicity in the late developmental stages of Drosophila melanogaster. This work illustrates the need for a full characterisation of the toxicity of AsHCs in experimental animals to finally assess the risk to human health related to the presence of arsenolipids in seafood.
We report a 1,2,3-triazol fluoroionophore for detecting Na+ that shows in vitro enhancement in the Na+-induced fluorescence intensity and decay time. The Na+-selective molecule 1 was incorporated into a hydrogel as a part of a fiber optical sensor. This sensor allows the direct determination of Na+ in the range of 1–10 mM by measuring reversible fluorescence decay time changes.
Das deutsche Zivilrecht geht davon aus, dass eine erwachsene, gesunde Person ihren Willen grundsätzlich fehlerfrei bilden und äußern kann. Eine Ausnahme gilt dann, wenn sie aufgrund besonderer geistiger oder körperlicher Umstände nicht die Fähigkeit zur freien Willensbildung besitzt. Willenserklärungen von Personen, die nicht dauerhaft, sondern nur für einen vorübergehenden Moment nicht fähig sind, ihren Willen so zu äußern wie sie es unter normalen Umständen tun würden, sind nach § 105 Absatz 2 BGB nichtig. Grund dafür ist entweder eine „Bewusstlosigkeit“ oder eine „vorübergehende Störung der Geistestätigkeit“. Die sorgfältige Auslegung des Tatbestands ist wichtig für die tägliche Entscheidungspraxis der Gerichte. Die Arbeit untersucht deshalb die Vorschrift des § 105 Absatz 2 BGB im historischen, juristischen und medizinischen Kontext, berücksichtigt dabei insbesondere die Abgrenzung zur Geschäftsunfähigkeit nach § 104 Nr. 2 BGB und geht der Anwendung der Vorschrift auf konkrete medizinische Störungen (alkoholbedingte Störungen, Abhängigkeit von illegalen Drogen, Epilepsien, Demenzen, Schizophrenien, neurotische Störungen, u.a.) nach.
Alexandra Silbermann entwickelt einen neuartigen, systematischen Ansatz, der eine ganzheitliche Analyse und Erklärung des Bewusstseins für einen gesunden Konsum zulässt und die Identifikation bedeutender Einflussfaktoren, die für Maßnahmen zugänglich sind, ermöglicht. Ohne fundierte Kenntnisse der kognitiven Prozesse, die dem gesundheitsbewussten Konsumentenverhalten zugrunde liegen, können Marketing- bzw. Interventionsmaßnahmen nur begrenzt wirkungsvoll sein. Die Autorin leitet Implikationen für eine effizientere Förderung gesundheitsbewussten Konsums ab. Die Systematisierung ist über den Gesundheitsbezug hinaus einsetzbar. Der Inhalt Arten des Bewusstseins als Systematisierungsansatz zentraler sozial-kognitiver Konstrukte der Verhaltensforschung Theoretische Darstellung der Determinanten gesundheitsbewussten Konsumentenverhaltens Empirische Prüfung des Modells zur Erklärung gesundheitsbewussten Konsumentenverhaltens Diskussion der Einflussfaktoren und deren Beziehungsstrukturen Implikationen für Marketingwissenschaft und -management Die Zielgruppen Dozierende und Studierende der Wirtschafts-, Sozial- und Gesundheitswissenschaften mit den Schwerpunkten Konsumentenverhalten, Marktforschung sowie präventive Gesundheitsförderung Praktiker in Marketing und Marktforschung bei Anbietern von Konsumgütern und in der präventiven Gesundheitsförderung Die AutorIn Alexandra Silbermann ist wissenschaftliche Mitarbeiterin an der Universität Potsdam bei Univ.-Prof. Dr. Ingo Balderjahn am Lehrstuhl für Marketing I.
Die steuerrechtliche Behandlung der Religionsgemeindschaften in Deutschland im Vergleich zu Südkorea
(2015)
Vom Kampf für den Frieden
(2014)
Molecular motors pulling cargos in the viscoelastic cytosol: how power strokes beat subdiffusion
(2014)
The discovery of anomalous diffusion of larger biopolymers and submicron tracers such as endogenous granules, organelles, or virus capsids in living cells, attributed to the viscoelastic nature of the cytoplasm, provokes the question whether this complex environment equally impacts the active intracellular transport of submicron cargos by molecular motors such as kinesins: does the passive anomalous diffusion of free cargo always imply its anomalously slow active transport by motors, the mean transport distance along microtubule growing sublinearly rather than linearly in time? Here we analyze this question within the widely used two-state Brownian ratchet model of kinesin motors based on the continuous-state diffusion along microtubules driven by a flashing binding potential, where the cargo particle is elastically attached to the motor. Depending on the cargo size, the loading force, the amplitude of the binding potential, the turnover frequency of the molecular motor enzyme, and the linker stiffness we demonstrate that the motor transport may turn out either normal or anomalous, as indeed measured experimentally. We show how a highly efficient normal active transport mediated by motors may emerge despite the passive anomalous diffusion of the cargo, and study the intricate effects of the elastic linker. Under different, well specified conditions the microtubule-based motor transport becomes anomalously slow and thus significantly less efficient.
Die Waffen nieder 2.0!
(2015)
Alles nur Strategie?
(2015)
Anomalous diffusion is frequently described by scaled Brownian motion (SBM){,} a Gaussian process with a power-law time dependent diffusion coefficient. Its mean squared displacement is ?x2(t)? [similar{,} equals] 2K(t)t with K(t) [similar{,} equals] t[small alpha]-1 for 0 < [small alpha] < 2. SBM may provide a seemingly adequate description in the case of unbounded diffusion{,} for which its probability density function coincides with that of fractional Brownian motion. Here we show that free SBM is weakly non-ergodic but does not exhibit a significant amplitude scatter of the time averaged mean squared displacement. More severely{,} we demonstrate that under confinement{,} the dynamics encoded by SBM is fundamentally different from both fractional Brownian motion and continuous time random walks. SBM is highly non-stationary and cannot provide a physical description for particles in a thermalised stationary system. Our findings have direct impact on the modelling of single particle tracking experiments{,} in particular{,} under confinement inside cellular compartments or when optical tweezers tracking methods are used.
Probably no other field of statistical physics at the borderline of soft matter and biological physics has caused such a flurry of papers as polymer translocation since the 1994 landmark paper by Bezrukov, Vodyanoy, and Parsegian and the study of Kasianowicz in 1996. Experiments, simulations, and theoretical approaches are still contributing novel insights to date, while no universal consensus on the statistical understanding of polymer translocation has been reached. We here collect the published results, in particular, the famous–infamous debate on the scaling exponents governing the translocation process. We put these results into perspective and discuss where the field is going. In particular, we argue that the phenomenon of polymer translocation is non-universal and highly sensitive to the exact specifications of the models and experiments used towards its analysis.
This study aims to further mechanistically understand toxic modes of action after chronic inorganic arsenic exposure. Therefore long-term incubation studies in cultured cells were carried out, to display chronically attained changes, which cannot be observed in the generally applied in vitro short-term incubation studies. Particularly, the cytotoxic, genotoxic and epigenetic effects of an up to 21 days incubation of human urothelial (UROtsa) cells with pico- to nanomolar concentrations of iAsIII and its metabolite thio-DMAV were compared. After 21 days of incubation, cytotoxic effects were strongly enhanced in the case of iAsIII and might partly be due to glutathione depletion and genotoxic effects on the chromosomal level. These results are in strong contrast to cells exposed to thio-DMAV. Thus, cells seemed to be able to adapt to this arsenical, as indicated among others by an increase in the cellular glutathione level. Most interestingly, picomolar concentrations of both iAsIII and thio-DMAV caused global DNA hypomethylation in UROtsa cells, which was quantified in parallel by 5-medC immunostaining and a newly established, reliable, high resolution mass spectrometry (HRMS)-based test system. This is the first time that epigenetic effects are reported for thio-DMAV; iAsIII induced epigenetic effects occur in at least 8000 fold lower concentrations as reported in vitro before. The fact that both arsenicals cause DNA hypomethylation at really low, exposure-relevant concentrations in human urothelial cells suggests that this epigenetic effect might contribute to inorganic arsenic induced carcinogenicity, which for sure has to be further investigated in future studies.
Diffusion of finite-size particles in two-dimensional channels with random wall configurations
(2014)
Diffusion of chemicals or tracer molecules through complex systems containing irregularly shaped channels is important in many applications. Most theoretical studies based on the famed Fick–Jacobs equation focus on the idealised case of infinitely small particles and reflecting boundaries. In this study we use numerical simulations to consider the transport of finite-size particles through asymmetrical two-dimensional channels. Additionally, we examine transient binding of the molecules to the channel walls by applying sticky boundary conditions. We consider an ensemble of particles diffusing in independent channels, which are characterised by common structural parameters. We compare our results for the long-time effective diffusion coefficient with a recent theoretical formula obtained by Dagdug and Pineda [J. Chem. Phys., 2012, 137, 024107].
Graphitic carbon nitride, g-C₃N₄, is a promising organic photo-catalyst for a variety of redox reactions. In order to improve its efficiency in a systematic manner, however, a fundamental understanding of the microscopic interaction between catalyst, reactants and products is crucial. Here we present a systematic study of water adsorption on g-C₃N₄ by means of density functional theory and the density functional based tight-binding method as a prerequisite for understanding photocatalytic water splitting. We then analyze this prototypical redox reaction on the basis of a thermodynamic model providing an estimate of the overpotential for both water oxidation and H⁺ reduction. While the latter is found to occur readily upon irradiation with visible light, we derive a prohibitive overpotential of 1.56 eV for the water oxidation half reaction, comparing well with the experimental finding that in contrast to H₂ production O₂ evolution is only possible in the presence of oxidation cocatalysts.
Welcher Diskurs wird um Jungenarbeit als geschlechtssensible pädagogische Arbeit mit männlichen Kindern und Jugendlichen und deren Umsetzung in kurzzeitpädagogischen außerunterrichtlichen Angeboten geführt? Thomas Viola Rieske geht dieser Frage nach und legt nahe, dass Normativität als unausweichlicher Bestandteil pädagogischer Praxis anerkannt und zugleich kritisch reflektiert werden muss, um Jungen in ihrer Entwicklung stärken zu können. Er diskutiert die verschiedenen geschlechtertheoretischen und pädagogischen Grundpositionen, die im Fachdiskurs über Jungenarbeit bestehen und untersucht die Umsetzung von Jungenarbeit. Er zeigt auf, dass die Teilnehmer der beobachteten Jungenseminare einerseits zu einem partnerschaftlichen, normenkritischen und direkten Kontakt mit sich und anderen befähigt werden, andererseits aber auch Zuschreibungen, Grenzüberschreitungen und ein Übergehen ihrer Bedürfnisse erfahren.
There is a wealth of evidence showing that increasing the distance between an argument and its head leads to more processing effort, namely, locality effects; these are usually associated with constraints in working memory (DLT: Gibson, 2000; activation-based model: Lewis and Vasishth, 2005). In SOV languages, however, the opposite effect has been found: antilocality (see discussion in Levy et al., 2013). Antilocality effects can be explained by the expectation-based approach as proposed by Levy (2008) or by the activation-based model of sentence processing as proposed by Lewis and Vasishth (2005). We report an eye-tracking and a self-paced reading study with sentences in Spanish together with measures of individual differences to examine the distinction between expectation- and memory-based accounts, and within memory-based accounts the further distinction between DLT and the activation-based model. The experiments show that (i) antilocality effects as predicted by the expectation account appear only for high-capacity readers; (ii) increasing dependency length by interposing material that modifies the head of the dependency (the verb) produces stronger facilitation than increasing dependency length with material that does not modify the head; this is in agreement with the activation-based model but not with the expectation account; and (iii) a possible outcome of memory load on low-capacity readers is the increase in regressive saccades (locality effects as predicted by memory-based accounts) or, surprisingly, a speedup in the self-paced reading task; the latter consistent with good-enough parsing (Ferreira et al., 2002). In sum, the study suggests that individual differences in working memory capacity play a role in dependency resolution, and that some of the aspects of dependency resolution can be best explained with the activation-based model together with a prediction component.
Wir sind eine IdeenUni
(2015)
Volksschädlinge vor Gericht
(2015)
Deutschland, September 1939. Der Zweite Weltkrieg hat gerade begonnen, die Kriegsmoral der deutschen Bevölkerung musste unter allen Umständen aufrechterhalten werden. Um ein Abklingen wie im Ersten Weltkrieg durch Aushungern zu vermeiden, musste die Versorgung der Bevölkerung mit Lebensmitteln und anderen lebenswichtigen Dingen stets gewährleistet sein.Jana Nüchterlein analysiert die am 5. September 1939 initiierte Volksschädlingsverordnung, nach der jeder, der die Verteilung verknappter und bezugsscheinpflichtiger Waren gefährdete, schwer bestraft werden sollte. Sie zeigt, dass mit der Verordnung vorrangig Ziele wie Abschreckung und Vertrauen der Bevölkerung in die Justiz (und damit in das System) erreicht werden sollten, und wie letztendlich – durch weitgefasste Tatbestände, scharfe Strafandrohungen und weit gespannte Strafrahmen – selbst die Gewährleistung der Durchführung kriegswirtschaftlicher Maßnahmen und die Unterbindung sämtlicher Formen der Sabotage zum Ziel wurden.
Das Handbuch umreißt das gesamte Spektrum der 2000jährigen Geschichte der Juden auf europäischem Boden. Wissenschaftler aus Europa und den USA haben ihre Forschungsergebnisse allgemein verständlich aufbereitet mit dem Ziel, das Leben und Wirken der Juden, aber auch die ihnen entgegengebrachte Intoleranz und deren Ursachen aufzuzeigen.
Der erste Teil konzentriert sich systematisch auf die Länder und Regionen, in denen Juden siedelten bzw. nach Vertreibungen aus anderen Staaten Aufnahme fanden. Es wird sowohl auf die innere Entwicklung der jüdischen Gemeinden als auch auf die Beziehungen zwischen Juden und der sie umgebenden andersgläubigen Gesellschaft eingegangen.
Der zweite Teil behandelt themenspezifische Schwerpunkte. Gemeindeleben und Religion, Familie und Stellung der Frau, kulturelle und geistige Entwicklung, aber auch Judenfeindschaft der sie umgebenden Gesellschaft – vom Antijudaismus bis zur Shoa und zum Antisemitismus der Gegenwart – werden in großangelegten Beiträgen dargelegt.
Das deutsche Strafgesetzbuch stellt nur die Fremdtötung und die Tötung auf Verlangen in den §§ 211ff. StGB unter Strafe. Der Suizid hingegen stellt keine Straftat dar, weshalb auch die Teilnahme daran straflos bleibt. Vor dem Hintergrund der sich hieraus ergebenden Abgrenzungsschwierigkeiten gibt es seit 2006 verschiedene Gesetzesvorhaben, die Suizidmitwirkung, insbesondere durch Sterbehilfeorganisationen, strafrechtlich zu erfassen. Die vorliegende Arbeit erörtert die in diesem Zusammenhang entstehende Fragestellung, ob die Teilnahme am Suizid ein strafwürdiges Verhalten darstellt, welches strafrechtlich geahndet werden muss. Hierzu werden auch die vorgenannten Gesetzesvorhaben einer kritischen Stellungnahme unterzogen und entsprechende ausländische Regelungen betrachtet. Neben den Entwürfen eines solchen Straftatbestandes geht die Arbeit außerdem auf rechtliche Lösungen außerhalb des Strafrechts ein und stellt abschließend fest, ob ein Erfordernis zur Änderung der bestehenden Rechtslage im Strafgesetzbuch besteht.
Der maskierte Voltaire
(2015)
Voltaire schrieb mit spitzer Feder, doch verbarg er seine Kritik mittels verdeckter Schreibarten. So schlüpft er in der Tischrunde der großen abendländischen Satiriker abwechselnd in die Masken von Lukian, Erasmus und Rabelais, um verwandte Geister miteinander sprechen zu lassen. – Im Drama Mahomet inszeniert er religiösen Fanatismus und Glaubenskriege als die große „Geißel“ der Menschheit. – Candide gerät als autofiktionale Spiegelung Voltaires und des Preußenkönigs Friedrich zu einer versteckten Abrechnung mit dem Freund. – Eine weite Lesart des Candide, eine Neuinterpretation unter dem Aspekt von Heterotopie und Heterologie, rückt die Neue Welt in den Blick. Unter Rückgriff auf das kartographische Imaginaire der Entdecker verwandeln sich geographische Orte in Heterotopien. Aspekte der Kolonialismuskritik und Globalisierung erweisen sich hier erstmals als eine wesentliche Strategie zur Ironisierung der ‚besten aller möglichen Welten‘.
Philipp Richter untersucht Unterschiede in der Makroorganisation der Landesverwaltungen. In seiner verwaltungswissenschaftlich-empirischen Analyse zeigt er am Beispiel der Versorgungsverwaltung, wie sich der vormals einheitliche Verwaltungsaufbau durch Verwaltungsstruktur- und Funktionalreformen zwischen den Bundesländern ausdifferenziert hat und wie die dadurch entstandenen Unterschiede den Vollzug von Bundesgesetzen beeinflussen. Mit Blick auf die Implementation des Schwerbehinderten- und Sozialen Entschädigungsrechts identifiziert der Autor problemadäquate Lösungen und zieht praxisrelevante Schlussfolgerungen für eine Modernisierung des äußeren Verwaltungsaufbaus, die auch wichtige Erkenntnisse für die Ausgestaltung der Makroorganisation in anderen Verwaltungsbereichen bereithalten.
Diese Arbeit untersucht, ob die Rassendiskriminierungskonvention (CERD) auf das Verhalten von Vertragsstaaten außerhalb ihres Staatsgebiets anwendbar ist. Unter Beachtung der bisherigen Rechtsprechung und Praxis anderer Menschenrechtsgremien zur Frage extraterritorialer Anwendbarkeit von Menschenrechtsverträgen werden die Entstehungsgeschichte, die Vorarbeiten zur CERD und die Praxis des CERD-Ausschusses analysiert. Diese Untersuchung bezieht auch das Verhalten der Vertragsstaaten mit ein. Die Struktur der CERD weist gegenüber anderen Menschenrechtsverträgen, die zur gleichen Zeit entstanden sind, Besonderheiten auf. Nur einzelne materielle Bestimmungen setzen die Ausübung von Hoheitsgewalt voraus. Unter diesem Aspekt sowie unter Berücksichtigung der in ihr enthaltenen Staatenpflichten wird die CERD in Bezug auf ihre extraterritoriale Anwendbarkeit erörtert. Anhand der Grundsätze des Völkerrechts werden Art und Umfang der Verpflichtungen, die den Vertragsstaaten unter der CERD auf fremdem Staatsgebiet aufgegeben werden können, diskutiert.
Das Treasury-Management von Internationalen Unternehmen gewinnt in der Praxis zunehmend an strategischer Bedeutung; eine wissenschaftlich umfassende Erörterung des Themas unter Berücksichtigung verschiedener Perspektiven und aktueller Entwicklungen fehlt jedoch. Daher wird in der vorliegenden Dissertation einerseits ein holistisches Verständnis des Treasury-Managements von Internationalen Unternehmen erarbeitet. Diese neuartige Sichtweise wird durch die Entwicklung von theoretischen Modellen untermauert und eine zunehmende Strategieorientierung nachgewiesen. Ergänzend wird das Treasury-Management vor dem Hintergrund einer Fokussierung auf Internationale Unternehmen und Finanzmärkte in einen Gesamtunternehmenskontext eingeordnet, aber auch Spezial-bereiche – wie die Corporate Governance der Treasury-Abteilung werden hinreichend behandelt. Daneben wird aber auch eine umfangreiche empirische Analyse der Bankensteuerung und des Cash-Managements von Internationalen Unternehmen am Beispiel von DAX- und MDAX-Unternehmen im Kontext der Globalen Finanzkrise durchgeführt. Es werden wesentliche Entwicklungstendenzen – wie eine zunehmende Risikoorientierung – aufgezeigt und ein Zusammenhang zwischen beiden Untersuchungsbereichen nachgewiesen.
The neurophysiological and behavioral correlates of action-related language processing have been debated for long time. A precursor in this field was the study by Buccino et al. (2005) combining transcranial magnetic stimulation (TMS) and behavioral measures (reaction times, RTs) to study the effect of listening to hand- and foot-related sentences. In the TMS experiment, the authors showed a decrease of motor evoked potentials (MEPs) recorded from hand muscles when processing hand-related verbs as compared to foot-related verbs. Similarly, MEPs recorded from leg muscles decreased when participants processed foot-related as compared to hand-related verbs. In the behavioral experiment, using the same stimuli and a semantic decision task the authors found slower RTs when the participants used the body effector (hand or foot) involved in the actual execution of the action expressed by the presented verb to give their motor responses. These findings were interpreted as an interference effect due to a simultaneous involvement of the motor system in both a language and a motor task. Our replication aimed to enlarge the sample size and replicate the findings with higher statistical power. The TMS experiment showed a significant modulation of hand MEPs, but in the sense of a motor facilitation when processing hand-related verbs. On the contrary, the behavioral experiment did not show significant results. The results are discussed within the general debate on the time-course of the modulation of motor cortex during implicit and explicit language processing and in relation to the studies on action observation/understanding.
Background: Interoceptive awareness (iA), the awareness of stimuli originating inside the body, plays an important role in human emotions and psychopathology. The insula is particularly involved in neural processes underlying iA. However, iA-related neural activity in the insula during the acute state of major depressive disorder (MDD) and in remission from depression has not been explored.
Methods: A well-established fMRI paradigm for studying (iA; heartbeat counting) and exteroceptive awareness (eA; tone counting) was used. Study participants formed three independent groups: patients suffering from MDD, patients in remission from MDD or healthy controls. Task-induced neural activity in three functional subdivisions of the insula was compared between these groups.
Results: Depressed participants showed neural hypo-responses during iA in anterior insula regions, as compared to both healthy and remitted participants. The right dorsal anterior insula showed the strongest response to iA across all participant groups. In depressed participants there was no differentiation between different stimuli types in this region (i.e., between iA, eA and noTask). Healthy and remitted participants in contrast showed clear activity differences.
Conclusions: This is the first study comparing iA and eA-related activity in the insula in depressed participants to that in healthy and remitted individuals. The preliminary results suggest that these groups differ in there being hypo-responses across insula regions in the depressed participants, whilst non-psychiatric participants and patients in remission from MDD show the same neural activity during iA in insula subregions implying a possible state marker for MDD. The lack of activity differences between different stimulus types in the depressed group may account for their symptoms of altered external and internal focus.
Background
Previous literature mainly introduced cognitive functions to explain performance decrements in dual-task walking, i.e., changes in dual-task locomotion are attributed to limited cognitive information processing capacities. In this study, we enlarge existing literature and investigate whether leg muscular capacity plays an additional role in children’s dual-task walking performance.
Methods
To this end, we had prepubescent children (mean age: 8.7 ± 0.5 years, age range: 7–9 years) walk in single task (ST) and while concurrently conducting an arithmetic subtraction task (DT). Additionally, leg lean tissue mass was assessed.
Results
Findings show that both, boys and girls, significantly decrease their gait velocity (f = 0.73), stride length (f = 0.62) and cadence (f = 0.68) and increase the variability thereof (f = 0.20-0.63) during DT compared to ST. Furthermore, stepwise regressions indicate that leg lean tissue mass is closely associated with step time and the variability thereof during DT (R2 = 0.44, p = 0.009). These associations between gait measures and leg lean tissue mass could not be observed for ST (R2 = 0.17, p = 0.19).
Conclusion
We were able to show a potential link between leg muscular capacities and DT walking performance in children. We interpret these findings as evidence that higher leg muscle mass in children may mitigate the impact of a cognitive interference task on DT walking performance by inducing enhanced gait stability.
Wer wird Vater und wann?
(2014)
Picosecond X-ray absorption spectroscopy (XAS) is used to investigate the electronic and structural dynamics initiated by plasmon excitation of 1.8 nm diameter Au nanoparticles (NPs) functionalised with 1-hexanethiol. We show that 100 ps after photoexcitation the transient XAS spectrum is consistent with an 8% expansion of the Au–Au bond length and a large increase in disorder associated with melting of the NPs. Recovery of the ground state occurs with a time constant of ∼1.8 ns, arising from thermalisation with the environment. Simulations reveal that the transient spectrum exhibits no signature of charge separation at 100 ps and allows us to estimate an upper limit for the quantum yield (QY) of this process to be <0.1.
New porous materials based on covalently connected monomers are presented. The key step of the synthesis is an acetalisation reaction. In previous years we used acetalisation reactions extensively to build up various molecular rods. Based on this approach, investigations towards porous polymeric materials were conducted by us. Here we wish to present the results of these studies in the synthesis of 1D polyacetals and porous 3D polyacetals. By scrambling experiments with 1D acetals we could prove that exchange reactions occur between different building blocks (evidenced by MALDI-TOF mass spectrometry). Based on these results we synthesized porous 3D polyacetals under the same mild conditions.
Modern microscopic techniques following the stochastic motion of labelled tracer particles have uncovered significant deviations from the laws of Brownian motion in a variety of animate and inanimate systems. Such anomalous diffusion can have different physical origins, which can be identified from careful data analysis. In particular, single particle tracking provides the entire trajectory of the traced particle, which allows one to evaluate different observables to quantify the dynamics of the system under observation. We here provide an extensive overview over different popular anomalous diffusion models and their properties. We pay special attention to their ergodic properties, highlighting the fact that in several of these models the long time averaged mean squared displacement shows a distinct disparity to the regular, ensemble averaged mean squared displacement. In these cases, data obtained from time averages cannot be interpreted by the standard theoretical results for the ensemble averages. Here we therefore provide a comparison of the main properties of the time averaged mean squared displacement and its statistical behaviour in terms of the scatter of the amplitudes between the time averages obtained from different trajectories. We especially demonstrate how anomalous dynamics may be identified for systems, which, on first sight, appear to be Brownian. Moreover, we discuss the ergodicity breaking parameters for the different anomalous stochastic processes and showcase the physical origins for the various behaviours. This Perspective is intended as a guidebook for both experimentalists and theorists working on systems, which exhibit anomalous diffusion.
Recently, C K-edge Near Edge X-ray Absorption Fine Structure (NEXAFS) spectra of graphite (HOPG) surfaces have been measured for the pristine material, and for HOPG treated with either bromine or krypton plasmas (Lippitz et al., Surf. Sci., 2013, 611, L1). Changes of the NEXAFS spectra characteristic for physical (krypton) and/or chemical/physical modifications of the surface (bromine) upon plasma treatment were observed. Their molecular origin, however, remained elusive. In this work we study by density functional theory, the effects of selected point and line defects as well as chemical modifications on NEXAFS carbon K-edge spectra of single graphene layers. For Br-treated surfaces, also Br 3d X-ray Photoelectron Spectra (XPS) are simulated by a cluster approach, to identify possible chemical modifications. We observe that some of the defects related to plasma treatment lead to characteristic changes of NEXAFS spectra, similar to those in experiment. Theory provides possible microscopic origins for these changes.
The toxicologically most relevant mercury (Hg) species for human exposure is methylmercury (MeHg). Thiomersal is a common preservative used in some vaccine formulations. The aim of this study is to get further mechanistic insight into the yet not fully understood neurotoxic modes of action of organic Hg species. Mercury species investigated include MeHgCl and thiomersal. Additionally HgCl2 was studied, since in the brain mercuric Hg can be formed by dealkylation of the organic species. As a cellular system astrocytes were used. In vivo astrocytes provide the environment necessary for neuronal function. In the present study, cytotoxic effects of the respective mercuricals increased with rising alkylation level and correlated with their cellular bioavailability. Further experiments revealed for all species at subcytotoxic concentrations no induction of DNA strand breaks, whereas all species massively increased H2O2-induced DNA strand breaks. This co-genotoxic effect is likely due to a disturbance of the cellular DNA damage response. Thus, at nanomolar, sub-cytotoxic concentrations, all three mercury species strongly disturbed poly(ADP-ribosyl)ation, a signalling reaction induced by DNA strand breaks. Interestingly, the molecular mechanism behind this inhibition seems to be different for the species. Since chronic PARP-1 inhibition is also discussed to sacrifice neurogenesis and learning abilities, further experiments on neurons and in vivo studies could be helpful to clarify whether the inhibition of poly(ADP-ribosyl)ation contributes to organic Hg induced neurotoxicity.
Arsenic-containing hydrocarbons are one group of fat-soluble organic arsenic compounds (arsenolipids) found in marine fish and other seafood. A risk assessment of arsenolipids is urgently needed, but has not been possible because of the total lack of toxicological data. In this study the cellular toxicity of three arsenic-containing hydrocarbons was investigated in cultured human bladder (UROtsa) and liver (HepG2) cells. Cytotoxicity of the arsenic-containing hydrocarbons was comparable to that of arsenite, which was applied as the toxic reference arsenical. A large cellular accumulation of arsenic, as measured by ICP-MS/MS, was observed after incubation of both cell lines with the arsenolipids. Moreover, the toxic mode of action shown by the three arsenic-containing hydrocarbons seemed to differ from that observed for arsenite. Evidence suggests that the high cytotoxic potential of the lipophilic arsenicals results from a decrease in the cellular energy level. This first in vitro based risk assessment cannot exclude a risk to human health related to the presence of arsenolipids in seafood, and indicates the urgent need for further toxicity studies in experimental animals to fully assess this possible risk.
We study the thermal Markovian diffusion of tracer particles in a 2D medium with spatially varying diffusivity D(r), mimicking recently measured, heterogeneous maps of the apparent diffusion coefficient in biological cells. For this heterogeneous diffusion process (HDP) we analyse the mean squared displacement (MSD) of the tracer particles, the time averaged MSD, the spatial probability density function, and the first passage time dynamics from the cell boundary to the nucleus. Moreover we examine the non-ergodic properties of this process which are important for the correct physical interpretation of time averages of observables obtained from single particle tracking experiments. From extensive computer simulations of the 2D stochastic Langevin equation we present an in-depth study of this HDP. In particular, we find that the MSDs along the radial and azimuthal directions in a circular domain obey anomalous and Brownian scaling, respectively. We demonstrate that the time averaged MSD stays linear as a function of the lag time and the system thus reveals a weak ergodicity breaking. Our results will enable one to rationalise the diffusive motion of larger tracer particles such as viruses or submicron beads in biological cells.
The role of flavonols and anthocyanins in the cold an UV-B acclimation of Arabidopsis thaliana (L.)
(2014)
Time-Travel-Treasures
(2014)
Vielheit statt Einheit
(2014)
Wir alle sind Nachbarn?
(2014)
Heimatgefühl als Schlüssel?
(2013)
Chillen gestern
(2013)
Von wegen Kinderspiel
(2013)
Herzog macht Stadt
(2012)
Bilder machen Geschichte
(2012)
The term “bilateral deficit” (BLD) has been used to describe a reduction in performance during bilateral contractions when compared to the sum of identical unilateral contractions. In old age, maximal isometric force production (MIF) decreases and BLD increases indicating the need for training interventions to mitigate this impact in seniors. In a cross-sectional approach, we examined age-related differences in MIF and BLD in young (age: 20–30 years) and old adults (age: >65 years). In addition, a randomized-controlled trial was conducted to investigate training-specific effects of resistance vs. balance training on MIF and BLD of the leg extensors in old adults. Subjects were randomly assigned to resistance training (n = 19), balance training (n = 14), or a control group (n = 20). Bilateral heavy-resistance training for the lower extremities was performed for 13 weeks (3 × / week) at 80% of the one repetition maximum. Balance training was conducted using predominately unilateral exercises on wobble boards, soft mats, and uneven surfaces for the same duration. Pre- and post-tests included uni- and bilateral measurements of maximal isometric leg extension force. At baseline, young subjects outperformed older adults in uni- and bilateral MIF (all p < .001; d = 2.61–3.37) and in measures of BLD (p < .001; d = 2.04). We also found significant increases in uni- and bilateral MIF after resistance training (all p < .001, d = 1.8-5.7) and balance training (all p < .05, d = 1.3-3.2). In addition, BLD decreased following resistance (p < .001, d = 3.4) and balance training (p < .001, d = 2.6). It can be concluded that both training regimens resulted in increased MIF and decreased BLD of the leg extensors (HRT-group more than BAL-group), almost reaching the levels of young adults.
On the role of fluoro-substituted nucleosides in DNA radiosensitization for tumor radiation therapy
(2014)
Gemcitabine (2′,2′-difluorocytidine) is a well-known radiosensitizer routinely applied in concomitant chemoradiotherapy. During irradiation of biological media with high-energy radiation secondary low-energy (<10 eV) electrons are produced that can directly induce chemical bond breakage in DNA by dissociative electron attachment (DEA). Here, we investigate and compare DEA to the three molecules 2′-deoxycytidine, 2′-deoxy-5-fluorocytidine, and gemcitabine. Fluorination at specific molecular sites, i.e., nucleobase or sugar moiety, is found to control electron attachment and subsequent dissociation pathways. The presence of two fluorine atoms at the sugar ring results in more efficient electron attachment to the sugar moiety and subsequent bond cleavage. For the formation of the dehydrogenated nucleobase anion, we obtain an enhancement factor of 2.8 upon fluorination of the sugar, whereas the enhancement factor is 5.5 when the nucleobase is fluorinated. The observed fragmentation reactions suggest enhanced DNA strand breakage induced by secondary electrons when gemcitabine is incorporated into DNA.
Polypeptoid block coloymers
(2014)
Cloud-RAID
(2014)
Das Bundesland
(2010)
Das Land und die Bezirke
(2010)