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Gottingen, Germany

The University of Göttingen , known informally as Georgia Augusta, is a Public comprehensive research university in the city of Göttingen, Germany. Founded in 1734 by George II, King of Great Britain and Elector of Hanover and starting classes in 1737, the university is the oldest in the state of Lower Saxony, and also the biggest in student enrollment, which stands at around 26,000. The university is highly renowned and respected both in Germany and in the world and has shaped Göttingen into a university city with a high student and faculty population. Wikipedia.

Clough Y.,University of Gottingen
Ecology | Year: 2012

The need to model and test hypotheses about complex ecological systems has led to a steady increase in use of path analytical techniques, which allow the modeling of multiple multivariate dependencies reflecting hypothesized causation and mechanisms. The aim is to achieve the estimation of direct, indirect, and total effects of one variable on another and to assess the adequacy of whole models. Path analytical techniques based on maximum likelihood currently used in ecology are rarely adequate for ecological data, which are often sparse, multi-level, and may contain nonlinear relationships as well as nonnormal response data such as counts or proportion data. Here I introduce a more flexible approach in the form of the joint application of hierarchical Bayes, Markov chain Monte Carlo algorithms, Shipley's d-sep test, and the potential outcomes framework to fit path models as well as to decompose and estimate effects. An example based on the direct and indirect interactions between ants, two insect herbivores, and a plant species demonstrates the implementation of these techniques, using freely available software. © 2012 by the Ecological Society of America.

Siewert I.,University of Gottingen | Gale zowska J.,Wroclaw Medical University
Chemistry - A European Journal | Year: 2015

Herein, we report the synthesis, the thermochemical data, and the catalytic reactivity of a new mononuclear cobalt complex, which has four NH protons in the ligand sphere. The combination of the redox-active metal ion and NH units enabled the coupling of proton and electron-transfer steps, which we exploited in the electrocatalytic water oxidation. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA.

Flot J.-F.,French Natural History Museum | Flot J.-F.,University of Gottingen
Molecular Ecology Resources | Year: 2010

The program phase is widely used for Bayesian inference of haplotypes from diploid genotypes; however, manually creating phase input files from sequence alignments is an error-prone and time-consuming process, especially when dealing with numerous variable sites and/or individuals. Here, a web tool called seqphase is presented that generates phase input files from fasta sequence alignments and converts phase output files back into fasta. During the production of the phase input file, several consistency checks are performed on the dataset and suitable command line options to be used for the actual phase data analysis are suggested. seqphase was written in perl and is freely accessible over the Internet at the address http://www.mnhn.fr/jfflot/seqphase. © 2009 Blackwell Publishing Ltd.

Sowa H.,University of Gottingen
Acta Crystallographica Section A: Foundations of Crystallography | Year: 2012

All homogeneous sphere packings and all interpenetrating layers of spheres were derived that can be realized in the ten orthorhombic trivariant lattice complexes belonging to the space groups of crystal class mmm without mirror symmetry. Altogether, sphere packings of 186 different types have been found; the maximal inherent symmetry is orthorhombic for 124 of these types. In addition, ten types of interpenetrating sphere packings were detected, and in three lattice complexes interpenetrating 6 3 nets occur. © 2012 International Union of Crystallography Printed in Singapore-all rights reserved.

Sulieman S.,University of Gottingen
Plant Signaling and Behavior | Year: 2011

The ability to regulate the rates of metabolic processes in response to changes in the internal and/or externa l environment is a fundamental feature which is inherent in all organisms. This adaptability is necessary for conserving the stability of the intercellular environment (homeostasis) which is essential for maintaining an efficient functional state in the organism. Symbiotic nitrogen fixation in legumes is an important process which establishes from the complex interaction between the host plant and microorganism. This process is widely believed to be regulated by the host plant nitrogen demand through a whole plant n feedback mechanism in particular under unfavorable conditions. This mechanism is probably triggered by the impact of shoot-borne, phloem-delivered substances. The precise mechanism of the potential signal is under debate, however, the whole phenomenon is probably related to a constant amino acid cycling within the plant, thereby signaling the shoot nitrogen status. Recent work indicating that there may be a flow of nitrogen to bacteroids is discussed in light of hypothesis that such a flow may be important to nodule function. Large amount of γ-aminobutyric acid (GABA) are cycled through the root nodules of the symbiotic plants. in this paper some recent evidence concerning the possible role of GABA in whole-plant-based upregulation of symbiotic nitrogen fixation will be reviewed. © 2011 Landes Bioscience.

Vicario C.M.,University of Queensland | Nitsche M.A.,University of Gottingen
Frontiers in Human Neuroscience | Year: 2013

Developmental dyslexia (DD) is a neuropsychological condition that is characterized by the persistent difficulty in learning to read amongst people with typical education, motivation, and normal intelligence (Goswami et al., 2006). On the other hand, a recent study (Callens et al., 2012) has pinpointed that when taking the full cognitive profile of students with DD into account, a quite consistent deficiency on a wide range of tasks, predominantly those involving the speed of processing and retrieval of verbal information from long term memory, can be identified. Improved reading by training programs in Childhood Congenital Dyslexia (CDD) leads rarely to full restitution, even in children submitted to intensive interventions. A major progress in the treatment of this disorder could originate from the development of complementary approaches that may enhance existing remediation programs by providing rehabilitation benefits that are larger and stable over time. © 2013 Vicario and Nitsche.

Bahns D.,University of Gottingen
Annales Henri Poincare | Year: 2010

It is shown that the n-point functions of scalar massive free fields on the noncommutative Minkowski space are distributions which are boundary values of analytic functions. Contrary to what one might expect, this construction does not provide a connection to the popular traditional Euclidean approach to noncommutative field theory (unless the time variable is assumed to commute). Instead, one finds Schwinger functions with twistings involving only momenta that are on the mass-shell. This explains why renormalization in the traditional Euclidean noncommutative framework crudely differs from renormalization in the Minkowskian regime. © 2010 The Author(s).

Albrecht S.C.,German Cancer Research Center | Barata A.G.,German Cancer Research Center | Grosshans J.,University of Gottingen | Teleman A.A.,German Cancer Research Center | Dick T.P.,German Cancer Research Center
Cell Metabolism | Year: 2011

The glutathione redox couple (GSH/GSSG) and hydrogen peroxide (H 2O 2) are central to redox homeostasis and redox signaling, yet their distribution within an organism is difficult to measure. Using genetically encoded redox probes in Drosophila, we establish quantitative in vivo mapping of the glutathione redox potential (E GSH) and H 2O 2 in defined subcellular compartments (cytosol and mitochondria) across the whole animal during development and aging. A chemical strategy to trap the in vivo redox state of the transgenic biosensor during specimen dissection and fixation expands the scope of fluorescence redox imaging to include the deep tissues of the adult fly. We find that development and aging are associated with redox changes that are distinctly redox couple-, subcellular compartment-, and tissue-specific. Midgut enterocytes are identified as prominent sites of age-dependent cytosolic H 2O 2 accumulation. A longer life span correlated with increased formation of oxidants in the gut, rather than a decrease. © 2011 Elsevier Inc.

Adiabatic compressibility data and principal dielectric relaxation times for aqueous solutions of 1:1 and 2:1 valent electrolytes are evaluated to yield their relative molal shifts B and B, respectively, at low solute concentration. Cationic (Bx) and anionic (Bx) contributions to these quantities are calculated and compared to one another. For some ions also the correspondent relative molal shifts (Bm in the intramolecular proton magnetic relaxation rates are considered. Clear correlations between Bκ values are found for most series of ions. Within the series of halide ions, for example, Bκ increases, whereas Bd decreases with anion radius. For large hydrophobic cations the opposite is true; that is, Bκ increases and Bd decreases with molar volume of ion. In general, the magnitudes |Bk in the changes of the compressibility coefficient are smaller than in the shifts of the dielectric relaxation time. The situation is more complicated with dielectrically saturated small ions. Since the apparently irrotationally bound water molecules around such ions do not contribute to the dielectric spectra by reorientation, comparison of compressibility changes with changes in the proton magnetic relaxation rate rather than in the dielectric relaxation time is more appropriate. Some composite ions, such as BF4O, show special features which can, however, be explained by a nonspherical charge distribution at the ion surface. © 2013 American Chemical Society.

The amount of resection is closely related to survival in brain tumours. To enhance resection, especially intraoperative magnetic resonance imaging (MRI) has been applied. The aim of this prospective, randomized study was to test if intraoperative 3-D ultrasound likewise can be used for resection control. 16 patients, who underwent surgery for intraaxial tumours in non-eloquent brain areas, were initially included into this prospective study. In two patients, the small size of the craniotomy hindered intraoperative ultrasound imaging. In 14 patients, 3-D ultrasound images were obtained before and after opening of the dura, during tumour removal, prior to evaluation by a blinded investigator for identification of tumour remnants, and after dura closure. Seven patients were randomized to complete tumour removal according to the impression of the surgeon (group 1). Seven patients were randomized to incomplete tumour removal (tumour remnant <1cm) (group 2); in these patients, the neurosurgeon intentionally left a tumour remnant prior to evaluation by the blinded investigator. The tumour remnant was then removed. It was tested if 3-D ultrasound can correctly identify complete and incomplete tumour resection. All patients underwent early postoperative MRI. In two patients (one each of the two groups) the image quality was too poor for a meaningful intraoperative evaluation. In the six patients randomized for incomplete tumour removal, 3-D ultrasound correctly identified tumour remnants in four patients (67%). In six patients randomized for complete tumour removal, 3-D ultrasound confirmed complete tumour resection in three patients. In addition, 3-D ultrasound identified correctly one tumour remnant in a patient randomized for complete tumour removal. Thus, the sensitivity for tumour remnant detection increased to 71% (five of seven patients) and that of confirmation of complete tumour removal was 60 % (three of five patients). The number of investigated patients is still to low to allow definite conclusions. However, the study results suggest, that 3-D ultrasound is especially helpful for detection of overseen brain tumour tissue.

Rizzoli S.O.,University of Gottingen
EMBO Journal | Year: 2014

Synaptic vesicle recycling is one of the best-studied cellular pathways. Many of the proteins involved are known, and their interactions are becoming increasingly clear. However, as for many other pathways, it is still difficult to understand synaptic vesicle recycling as a whole. While it is generally possible to point out how synaptic reactions take place, it is not always easy to understand what triggers or controls them. Also, it is often difficult to understand how the availability of the reaction partners is controlled: how the reaction partners manage to find each other in the right place, at the right time. I present here an overview of synaptic vesicle recycling, discussing the mechanisms that trigger different reactions, and those that ensure the availability of reaction partners. A central argument is that synaptic vesicles bind soluble cofactor proteins, with low affinity, and thus control their availability in the synapse, forming a buffer for cofactor proteins. The availability of cofactor proteins, in turn, regulates the different synaptic reactions. Similar mechanisms, in which one of the reaction partners buffers another, may apply to many other processes, from the biogenesis to the degradation of the synaptic vesicle. Silvio Rizzoli reviews the different steps and mechanisms involved in synaptic vesicle biogenesis and recycling. © 2014 The Authors.

Irniger S.,University of Gottingen
Molecular Microbiology | Year: 2011

Ime2 of the budding yeast Saccharomyces cerevisiae belongs to a family of conserved protein kinases displaying sequence similarities to both cyclin-dependent kinases and mitogen-activated protein kinases. Ime2 has a pivotal role for meiosis and sporulation. The involvement of this protein kinase in the regulation of various key events in meiosis, such as the initiation of DNA replication, the expression of meiosis-specific genes and the passage through the two consecutive rounds of nuclear divisions has been characterized in detail. More than 20 years after the identification of the IME2 gene, a recent report has provided the first evidence for a function of this gene outside of meiosis, which is the regulation of pseudohyphal growth. In the last few years, Ime2-related protein kinases from various fungal species were studied. Remarkably, these homologues are not generally required for meiosis, but instead have other specific tasks. In filamentous ascomycete species, Ime2 homologues are involved in the inhibition of fruiting body formation in response to environmental signals. In the pathogenic basidiomycetes Ustilago maydis and Cryptococcus neoformans, members of this kinase family apparently have primary roles in regulating mating. Thus, Ime2-related kinases exhibit an amazing variety in controlling sexual developmental programs in fungi. © 2011 Blackwell Publishing Ltd.

Hustert R.,University of Gottingen
Arthropod Structure and Development | Year: 2012

Miniaturization effects in the central nervous system (CNS) of a very small calchicid wasp, Encarsia formosa (0.6 mm long), are obvious for the overall morphology and at the level of axon sizes. Parasagittal sections show that most ganglia are fused and leave connectives only in the neck and the petiole. The thoracic complex is partly squeezed between muscles, enwraps cuticular apodemes and protrudes laterally into the coxae of legs. Somata of neurons are similar in size and form a multiple layer around large neuropile regions of the CNS. In TEM sections of connectives the range of axon diameters lies between 0.045 and 3.8 μm. Extremely small axon diameters below 0.1 μm are supposed to present spatial restrictions for ion channels and internal organelles. In theory, that can cause frequent spontaneous releases of action potentials (AP) which impede regular information transfer by normal APs. Therefore, axon sizes were studied in connectives between ganglia where longer distance information transfer requires action potentials even in the smallest axons. The diameters of many interganglionic axons below 0.08 μm contradict the theory. The luxury of large axon diameters exceeding 2-3 μm is reserved for several " giant" interneurons in the thoracic and in the abdominal ganglion complex. They should belong to rapid sensory alerting systems. The largest, a bilateral pair in the abdominal CNS, could integrate afferents from long wind sensitive hairs on the abdomen. © 2012 Elsevier Ltd.

Harlov D.E.,Helmholtz Center Potsdam | Van Den Kerkhof A.,University of Gottingen | Johansson L.,Lund University
Journal of Petrology | Year: 2013

The Varberg-Torpa charnockite-granite association (Varberg, SW Sweden) consists of the magmatic Varberg charnockite (1399±12 Ma) and theTorpa granite (1380±12 Ma). TheTorpa granite is both continuous and, based on its whole-rock geochemistry, synmagmatic with the Varberg charnockite. The granite body also contains a number of charnockite inliers. P-T estimation using garnet-clinopyroxene and orthopyroxene-clinopyroxene Fe-Mg exchange thermometry and garnet-orthopyroxene-plagioclase-quartz barometry gives temperatures and pressures (750-8508C; 800-850MPa) that most probably approximate the P-Tconditions during emplacement of the charnockite compared with a lower crystallization temperature (650-700°C) for the granite. The earliest recognized fluid inclusions in both the granite and charnockite consist of H2O-CO2 mixtures (H2O volume fraction 0·2-0·7). Fluid inclusions in the charnockite are characterized by high CO2 densities (up to 1·0 gcm-3; 40-90% bulk CO2), of probable magmatic origin, and are best preserved in garnet, plagioclase, and fluorapatite (in order of decreasing CO2 densities),and sometimes also in clinopyroxene. Fluid inclusions with the highest CO2 densities (1·08-1·10 gcm-3) are found in quartz (Th -31 to -36°C) and may have originated under high P-Tconditions during emplacement and cooling of the charnockite. Magmatic fluids in the granite correspond to aqueous- carbonic inclusions with an estimated bulk composition (mol %) of H2O 73%, CO2 25%, NaCl 2%. The salinity of the solutes in the granite (typically 14-20 wt % NaCl-eq.) is generally higher than for the charnockite (0-8 wt % NaCl-eq.). Field, petrographic,mineralogical, geochemical, and fluid inclusion evidence indicates that, compared with the H2O-rich granite, the magma responsible for the charnockite had a preponderance of CO2 over H2O, which lowered the H2Oactivity in the melt, stabilizing ortho- and clinopyroxene. This evidence alsosupports the idea that the granite and charnockite were derived from a common source magma (most probably a fluid-rich basalt at the base of the crust) as a result of fractional crystallization. © The Author 2012. Published by Oxford University Press. All rights reserved.

Hauck M.,University of Gottingen | Lkhagvadorj D.,Mongolian State University of Agriculture
Ecological Indicators | Year: 2013

The ecological impact of the traditional land use by pastoral nomads on forest ecosystems is little studied. We analyzed the influence of livestock density on epiphytic lichen diversity in larch forests of the Mongolian forest-steppe, which we selected as a case example because pastoral nomadism is here most widespread within Central Asia. Canonical correspondence analysis showed that the epiphytic lichen vegetation was strongly influenced by the livestock density within a radius of 1 km around the sampled forests. Goats together with horses were most significant at shaping lichen vegetation in the forest edges as were horses alone in the forest interiors. This result matches with the results of interviews with 169 herder families and own field observations, which substantiate that goats preferably graze at the edges, whereas horses often browse the interiors. The livestock impact is thought to be primarily exerted through fertilization by the animals and mechanical abrasion. Based on an indicator species analyses, we propose to use epiphytic lichens as indicators of the grazing impact at different livestock densities in the Mongolian forest-steppe. The proposed indication system can be used as a tool for the rapid assessment of the livestock grazing impact. It has the advantage that it is thought to average the livestock impact of several years, which is important with regard to the nomadic style of livestock husbandry. The use of lichens as indicator species can at least partly substitute the time-consuming interviewing of the herder families to assess livestock densities and their impact on forest biodiversity. The proposed indicator system could thus be used as a planning tool for purposes of nature conservation. © 2013 Elsevier Ltd.

Dosch R.,University of Gottingen
Critical Reviews in Biochemistry and Molecular Biology | Year: 2015

In many animals, factors deposited by the mother into the egg control the earliest events in development of the zygote. These maternal RNAs and proteins play critical roles in oocyte development and the earliest steps of embryogenesis such as fertilization, cell division and embryonic patterning. Here, this article summarizes recent discoveries made on the maternal control of germline specification in zebrafish. Moreover, this review will discuss the major gaps remaining in our understanding of this process and highlight recent technical innovations in zebrafish, which allow tackling some of these questions in the near future. © 2014 Informa Healthcare USA, Inc. All rights reserved.

Claussen I.,University of Gottingen | Mayr S.G.,University of Leipzig
New Journal of Physics | Year: 2011

We report on vibrating reed measurements combined with density functional theory-based calculations to assess the elastic and damping properties of Fe-Pd ferromagnetic shape memory alloy splats. While the austenite-martensite phase transformation is generally accompanied by lattice softening, a severe modulus defect and elevated damping behavior are characteristic of the martensitic state. We interpret the latter in terms of twin boundary motion between pinning defects via partial 'twinning' dislocations. Energy dissipation is governed by twin boundary drag, primarily due to lattice imperfections, as concluded from the temperature dependence of damping and related activation enthalpies. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

Effendi Y.,Leibniz University of Hanover | Rietz S.,Max Planck Institute for Plant Breeding Research | Fischer U.,University of Gottingen | Scherer G.F.E.,Leibniz University of Hanover
Plant Journal | Year: 2011

Summary AUXIN-BINDING PROTEIN 1 (ABP1) is not easily accessible for molecular studies because the homozygous T-DNA insertion mutant is embryo-lethal. We found that the heterozygous abp1/ABP1 insertion mutant has defects in auxin physiology-related responses: higher root slanting angles, longer hypocotyls, agravitropic roots and hypocotyls, aphototropic hypocotyls, and decreased apical dominance. Heterozygous plants flowered earlier than wild-type plants under short-day conditions. The length of the main root, the lateral root density and the hypocotyl length were little altered in the mutant in response to auxin. Compared to wild-type plants, transcription of early auxin-regulated genes (IAA2, IAA11, IAA13, IAA14, IAA19, IAA20, SAUR9, SAUR15, SAUR23, GH3.5 and ABP1) was less strongly up-regulated in the mutant by 0.1, 1 and 10 μm IAA. Surprisingly, ABP1 was itself an early auxin-up-regulated gene. IAA uptake into the mutant seedlings during auxin treatments was indistinguishable from wild-type. Basipetal auxin transport in young roots was slower in the mutant, indicating a PIN2/EIR1 defect, while acropetal transport was indistinguishable from wild-type. In the eir1 background, three of the early auxin-regulated genes tested (IAA2, IAA13 and ABP1) were more strongly induced by 1 μm IAA in comparison to wild-type, but eight of them were less up-regulated in comparison to wild-type. Similar but not identical disturbances in regulation of early auxin-regulated genes indicate tight functional linkage of ABP1 and auxin transport regulation. We hypothesize that ABP1 is involved in the regulation of polar auxin transport, and thus affects local auxin concentration and early auxin gene regulation. In turn, ABP1 itself is under the transcriptional control of auxin. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

Stadelmann C.,University of Gottingen
Current Opinion in Neurology | Year: 2011

Purpose of Review: Multiple sclerosis (MS) treatments targeting the inflammatory nature of the disease have become increasingly effective in recent years. However, our efforts at targeting the progressive disease phase have so far been largely unsuccessful. This has led to the hypothesis that disease mechanisms independent of an adaptive immune response contribute to disease progression and closely resemble neurodegeneration. Recent Findings: Nonfocal, diffuse changes in the MS brain, especially axonal loss and mitochondrial dysfunction, prove better correlates of disability than total lesion load and have been associated with disease progression. Molecular changes in nondemyelinated MS tissue also suggest that alterations in the MS brain are widespread and consist of pro-inflammatory as well as anti-inflammatory responses. However, local lymphocytic inflammation and microglial activation are salient features of the chronic disease, and T-cell-mediated inflammation contributes to tissue damage. In addition, neuroaxonal cytoskeletal alterations have been associated with disease progression. Summary: Our knowledge of the molecular mechanisms leading to neuroaxonal damage and demise in MS is steadily increasing. Experimental therapies targeting neuroaxonal ionic imbalances and energy metabolism in part show promising results. A better understanding of the molecular mechanisms underlying chronic progression will substantially aid the development of new treatment strategies. © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Hair fibre is regarded as a unique mammalian feature with an important role for endothermy. Artificial selection for hair characteristics resulted in marked changes with regard to follicle number, type, distribution, growth and natural shedding. This review focuses on the fine fibre-producing South American camelids (SACs) and the relationship between their hair coat and thermoregulation. SACs have developed several special integumental characteristics. While the hair coat of the wild lamoids vicua (Vicugna vicugna) and guanaco (Lama guanicoe) is formed by two types of hair (the coarse outer guard hairs and a finer undercoat), the domesticated llamas (Lama glama) and alpaca (Lama pacos) exhibit variably double coat and predominantly single coat, respectively. The distribution of the hair coat across the body is not homogenous. Thermal windows with shorter hair or thinner skin can be identified at the ventral abdomen, axillary space and inside of the thighs (about 20% of the skin), thus allowing to modulate heat dissipation. In contrast to sheep wool, lamoid fibres are mainly medullated. The thermal conductance of summer pelage was higher than that of the winter fleece and highest for the axillar and lower flanks. Lamoids have developed behavioural strategies to modify heat loss by adopting specific postures according to ambient conditions by closing or opening the thermal windows. Energy savings of 67% attributed to posture were calculated. SACs have shown to be able to adapt to a broad range of different climatic conditions. The specific integumental characteristics of SACs indicate that they have developed adaptation mechanisms particularly suited for cooler climates. Accordingly, hyperthermia might become a problem in hot, humid areas outside of their original habitat. Several studies showed the beneficial effect of shearing against heat stress. In particular, fertility in males exposed to heat stress may be improved by shearing. Infrared thermography reveals that in shorn animals the heat is radiated across the entire body surface and is not restricted to the thermal windows. However, shearing also changes the conditions of the protective layer, resulting in a loss of thermal conductance that may result in adverse effects when animals are kept under cold temperatures. The length of residual fibre appears to be crucial in avoiding excessive heat loss in a cold environment, as demonstrated by shearing experiments with different shearing machines. There is, therefore, potential for welfare considerations to conflict with industrial demands for fibre length or homogenous quality. Copyright © The Animal Consortium 2009.

Brockmann K.,University of Gottingen
Current Neurology and Neuroscience Reports | Year: 2013

Episodic dyskinetic movement disorders are a heterogeneous group of rare conditions. Paroxysmal dyskinesias constitute the core of this group and usually exhibit normal interepisodic neurologic findings. Contrariwise, episodic dyskinesias occur as a particular feature of complex chronic neurologic disorders. Conjunction of accurate phenotyping with up-to-date methods of molecular genetics recently provided remarkable new insights concerning the genetic causes of episodic dyskinesia. The identification of heterozygous mutations in the PRRT2 gene in paroxysmal kinesigenic dyskinesia as well as in benign familial infantile seizures linked episodic movement disorders with epilepsy. Alternating hemiplegia of childhood, the prototype of a chronic multisystem disease with episodic dyskinesia as a clinical hallmark, was recently found to be caused by heterozygous de novo mutations in the ATP1A3 gene. The clinical spectra of PRRT2 as well as of ATP1A3 mutations are still expanding. This review summarizes new genetic findings and clinical aspects in episodic dyskinesias. © 2013 Springer Science+Business Media New York.

Friederich S.,University of Gottingen
Studies in History and Philosophy of Science Part B - Studies in History and Philosophy of Modern Physics | Year: 2013

The paper discusses objections against non-hidden variable versions of the epistemic conception of quantum states-the view that quantum states do not describe the properties of quantum systems but reflect, in some way to be specified, the epistemic conditions of agents assigning them. In the first half of the paper, the main motivation for the epistemic conception of quantum states is sketched, and a version of it is outlined, which combines ideas from an earlier study of it (Friederich, 2011) with elements of Richard Healey's recent pragmatist interpretation of quantum theory (Healey, 2012). In the second half, various objections against epistemic accounts of quantum states are discussed in detail, which are based on criticisms found in the literature. Possible answers by the version outlined here are compared with answers from the quantum Bayesian point of view, which is at present the most discussed version of the epistemic conception of quantum states. © 2013 Elsevier Ltd.

Ackermann L.,University of Gottingen
Journal of Organic Chemistry | Year: 2014

Catalytic C-H functionalizations are increasingly viable tools for sustainable syntheses. In recent years, inexpensive cobalt complexes were identified as powerful catalysts for C-H arylations with challenging organic electrophiles. In particular, cobalt complexes of N-heterocyclic carbenes enabled high catalytic efficacy under exceedingly mild reaction conditions. This strategy set the stage for challenging direct alkylations with primary and sterically hindered secondary alkyl halides. Herein, the recent rapid evolution of cobalt-catalyzed C-H transformations with organic electrophiles is reviewed until summer 2014. © 2014 American Chemical Society.

In the context of personalized psychiatry there is growing interest in the development of neuroimaging markers for differential diagnosis and individualized therapy of mental disorders. This article reports on new neuroimaging markers for the diagnosis of Alzheimer's disease and particularly recent multi-functional magnetic resonance imaging (m-fMRI) studies in patients with schizophrenic and affective psychoses. Using experimental key paradigms for targeted assessment of pathophysiologically relevant neurofunctional systems, these studies reveal both differences and commonalities between the diagnostic categories. In addition, the article outlines research strategies for further development of the classification of major psychoses on the basis of a more precise characterization of the neurofunctional and pathophysiological phenotype. Multivariate approaches may help to identify more complex neuroimaging markers relevant for diagnosis and/or prognosis. Finally, some examples will be presented for the use of neuroimaging markers in the individualized choice of therapy. © 2011 Springer-Verlag.

Hardeland R.,University of Gottingen
Interdisciplinary Topics in Gerontology | Year: 2014

From the perspective of systems biology, melatonin is relevant to aging in multiple ways. As a highly pleiotropic agent, it acts as a modulator and protectant of mitochondrial electron flux, a potent antioxidant that supports the redox balance and prevents excessive free radical formation, a coregulator of metabolic sensing and antagonist of insulin resistance, an immune modulator, a physiological hypnotic and, importantly, an orchestrating chronobiotic. It entrains central and peripheral circadian clocks and is required for some high-amplitude rhythms. The circadian system, which controls countless functions, is composed of many cellular oscillators that involve various accessory clock proteins, some of which are modulated by melatonin, e.g. sirtuin 1, AMP-dependent protein kinase, and protein kinase C. Aging and age-related diseases are associated with losses in melatonin secretion and rhythm amplitudes. The dynamic properties of aging processes deserve particular attention. This concerns especially two vicious cycles, one of peroxynitrite formation driven by inflammation or overexcitation, another one of inflammaging driven by the senescence-associated secretory phenotype, and additionally the loss of dynamics in a deteriorating circadian multioscillator system. © 2015 S. Karger AG, Basel.

Raupach T.,University of Gottingen | Hoogsteder P.H.J.,Maastricht University | Van Schayck C.P.O.,Maastricht University
Drugs | Year: 2012

Tobacco smoking causes cardiovascular, respiratory and malignant disease, and stopping smoking is among the key medical interventions to lower the worldwide burden of these disorders. However, the addictive properties of cigarette smoking, including nicotine inhalation, render most quit attempts unsuccessful. Recommended therapies, including combinations of counselling and medication, produce long-term continuous abstinence rates of no more than 30. Thus, more effective treatment options are needed.An intriguing novel therapeutic concept is vaccination against nicotine. The basic principle of this approach is that, after entering the systemic circulation, a substantial proportion of nicotine can be bound by antibodies. Once bound to antibodies, nicotine is no longer able to cross the blood-brain barrier. As a consequence, the rewarding effects of nicotine are diminished, and relapse to smoking is less likely to occur. Animal studies indicate that antibodies profoundly change the pharmacokinetics of the drug and can interfere with nicotine self-administration and impact on the severity of withdrawal symptoms. To date, five phase III clinical trials using vaccines against nicotine have been published. Results have been disappointing in that an increase in quit rates was only observed in small groups of smokers displaying particularly high antibody titres.The failure of encouraging preclinical data to completely translate to clinical studies may be partially explained by shortcomings of animal models of addiction and an incomplete understanding of the complex physiological and behavioural processes contributing to tobacco addiction. This review summarizes the current status of research and suggests some directions for the future development of vaccines against nicotine. Ideally, these vaccines could one day become part of a multifaceted approach to treating tobacco addiction that includes counselling and pharmacotherapy. © 2012 Adis Data Information BV. All rights reserved.

Noubactep C.,University of Gottingen | Noubactep C.,Kultur und Nachhaltige Entwicklung CDD e.V. | Care S.,University Paris Est Creteil
Journal of Hazardous Materials | Year: 2011

Despite the amount of data available on investigating the process of aqueous contaminant removal by metallic iron (Fe0), there is still a significant amount of uncertainty surrounding the design of Fe0 beds for laboratory testing to determine the suitability of Fe0 materials for field applications. Available data were obtained under various operating conditions (e.g., column characteristics, Fe0 characteristics, contaminant characteristics, oxygen availability, solution pH) and are hardly comparable to each other. The volumetric expansive nature of iron corrosion has been univocally reported as major drawback for Fe0 beds. Mixing Fe0 with inert materials has been discussed as an efficient tool to improve sustainability of Fe0 beds. This paper discusses some problems associated with the design of Fe0 beds and proposes a general approach for the characterization of Fe0 beds. Each Fe0 column should be characterized by its initial porosity, the composition of the steady phase and the volumetric proportion of individual materials. Used materials should be characterized by their density, porosity, and particle size. This work has introduced simple and reliable mathematical equations for column design, which include the normalisation of raw experimental data prior to any data treatment. © 2011 Elsevier B.V.

Cakoni F.,University of Delaware | Kress R.,University of Gottingen
Inverse Problems | Year: 2013

Determining the shape of an inclusion within a conducting medium from voltage and current measurements on the accessible boundary of the medium can be modeled as an inverse boundary value problem for the Laplace equation. We present a solution method for such an inverse boundary value problem with a generalized impedance boundary condition on the inclusion via boundary integral equations. Both the determination of the unknown boundary and the determination of the unknown impedance functions are considered. In addition to describing the reconstruction algorithms and illustrating their feasibility by numerical examples, we also obtain a uniqueness result on determining the impedance coefficients. © 2013 IOP Publishing Ltd.

Luke D.R.,University of Gottingen
Journal of Mathematical Imaging and Vision | Year: 2013

We present an analysis of sets of matrices with rank less than or equal to a specified number s. We provide a simple formula for the normal cone to such sets, and use this to show that these sets are prox-regular at all points with rank exactly equal to s. The normal cone formula appears to be new. This allows for easy application of prior results guaranteeing local linear convergence of the fundamental alternating projection algorithm between sets, one of which is a rank constraint set. We apply this to show local linear convergence of another fundamental algorithm, approximate steepest descent. Our results apply not only to linear systems with rank constraints, as has been treated extensively in the literature, but also nonconvex systems with rank constraints. © 2012 The Author(s).

D'Adderio M.,University of Gottingen | Moci L.,University of Rome La Sapienza
Journal of Combinatorial Theory. Series A | Year: 2013

We introduce the notions of arithmetic colorings and arithmetic flows over a graph with labelled edges, which generalize the notions of colorings and flows over a graph. We show that the corresponding arithmetic chromatic polynomial and arithmetic flow polynomial are given by suitable specializations of the associated arithmetic Tutte polynomial, generalizing classical results of Tutte (1954) [9]. © 2012 Elsevier Inc.

Straube S.,University of Gottingen
Cochrane database of systematic reviews (Online) | Year: 2010

BACKGROUND: Gabapentin is an antiepileptic drug, also used in the treatment of neuropathic pain, which is the subject of a Cochrane review, currently under revision. Its efficacy in treating established acute postoperative pain has not been demonstrated. OBJECTIVES: To assess the efficacy and safety of single dose oral gabapentin compared with placebo in established acute postoperative pain using methods that permit comparison with other analgesics. SEARCH STRATEGY: We searched Cochrane CENTRAL, MEDLINE, EMBASE, and the Oxford Pain Relief Database. Additional studies were sought from reference lists of retrieved articles and reviews. Clinical trials databases were searched for unpublished studies; clinical trial reports of several unpublished studies have been made public following litigation in the US. SELECTION CRITERIA: Single oral dose, randomised, double-blind, placebo-controlled trials of gabapentin for relief of established moderate to severe postoperative pain in adults. DATA COLLECTION AND ANALYSIS: Studies were assessed for methodological quality and data extracted by two review authors independently. Numbers of participants with at least 50% of maximum possible total pain relief (TOTPAR) or summed pain intensity difference (SPID) with gabapentin or placebo were calculated and used to derive relative benefit (RB) or risk (RR), and number-needed-to-treat-to-benefit (NNT). Numbers of participants using rescue medication, and time to its use, were sought as additional measures of efficacy. Information on adverse events and withdrawals was collected. MAIN RESULTS: Four unpublished studies met inclusion criteria; in three, participants had pain following dental surgery, and one followed major orthopaedic surgery; 177 participants were treated with a single dose of gabapentin 250 mg, 21 with gabapentin 500 mg, and 172 with placebo. At least 50% pain relief over 6 hours was achieved by 15% with gabapentin 250 mg and 5% with placebo; giving a RB of 2.5 (95% CI 1.2 to 5.0) and an NNT of 11 (6.4 to 35). Significantly fewer participants needed rescue medication within 6 hours with gabapentin 250 mg than with placebo; NNT to prevent use 5.8. About one third of participants reported adverse events with both gabapentin 250 mg and placebo. No serious adverse events occurred with gabapentin. AUTHORS' CONCLUSIONS: Gabapentin 250 mg is statistically superior to placebo in the treatment of established acute postoperative pain, but the NNT of 11 for at least 50% pain relief over 6 hours with gabapentin 250 mg is of limited clinical value and inferior to commonly used analgesics. Gabapentin 250 mg is not clinically useful as a stand-alone analgesic in established acute postoperative pain, though this is probably the first demonstration of analgesic effect of an antiepileptic in established acute pain.

Thoms S.,University of Gottingen
Open Biology | Year: 2015

Peroxisomes are capable of importing folded and oligomeric proteins. However, it is a matter of dispute whether oligomer import by peroxisomes is the exception or the rule. Here, I argue for a clear distinction between homo-oli-gomeric proteins that are essentially peroxisomal, and dually localized hetero-oligomers that access the peroxisome by piggyback import, localizing there in limited number, whereas the majority remain in the cytosol. Homooligomeric proteins comprise the majority of all peroxisomal matrix proteins. There is evidence that binding by Pex5 in the cytosol can regulate their oligomerization state before import. The hetero-oligomer group is made up of superoxide dismutase and lactate dehydrogenase. These proteins have evolved mechanisms that render import inefficient and retain the majority of proteins in the cytosol. © 2015 The Authors.

Skoruppa K.,University of Essex | Mani N.,University of Gottingen | Peperkamp S.,Laboratoire Of Science Cognitives Et Psycholinguistique
Child Development | Year: 2013

Using a picture pointing task, this study examines toddlers' processing of phonological alternations that trigger sound changes in connected speech. Three experiments investigate whether 2;5- to 3-year-old children take into account assimilations-processes by which phonological features of one sound spread to adjacent sounds-for the purpose of word recognition (e.g., in English, ten pounds can be produced as te[mp]ounds). English toddlers (n=18) show sensitivity to native place assimilations during lexical access in Experiment 1. Likewise, French toddlers (n=27) compensate for French voicing assimilations in Experiment 2. However, French toddlers (n=27) do not take into account a hypothetical non-native place assimilation rule in Experiment 3, suggesting that compensation for assimilation is already language specific. © 2012 Society for Research in Child Development, Inc.

Zinngrebe Y.M.,University of Gottingen
Ecology and Society | Year: 2016

In the mega-diverse country Peru, a resource intensive development model collides with the interest of conserving biodiversity. Peruvian biodiversity experts have developed different lines of argumentation as to how to integrate conservation into the sustainable development of their country. Applying grounded theory, I define five groups of conservation narratives based on the analysis of 72 qualitative interviews with experts working in areas of biodiversity conservation. I have labeled them: biodiversity protectionists, biodiversity traditionalists, biodiversity localists, biodiversity pragmatists, and biodiversity capitalists. These groups are each discussed in connection with what they have to say about biodiversity in relation to human life, valuation and knowledge systems, participation and leadership, substitutability of natural capital, and its predominant political strategy. In a second step, a comparative analysis of the dominant and diverging political perspectives is made. I argue that by deconstructing underlying premises and ideologies, common ground and possible opportunities for collaboration can be identified. Moreover, although the presented results can serve as a discussion scaffold to organize conservation debates in Peru, this example demonstrates how the terms biodiversity and sustainability are operationalized in conservation narratives. © 2016 by the author(s).

Gagnevin D.,University College Dublin | Daly J.S.,University College Dublin | Kronz A.,University of Gottingen
Contributions to Mineralogy and Petrology | Year: 2010

This study documents the chemical and textural responses of zircon in the Elba igneous complex, with particular reference to the 7- to 7.8-Ma-old Monte Capanne pluton in relation to its coeval volcanic counterpart (Capraia), using BSE imaging and quantitative electron microprobe analyses. The Monte Capanne pluton displays multiple field and geochemical evidence for magma mixing. The samples we have investigated (including monzogranitic, mafic enclave and dyke samples) display similar zircon textures and are associated with an extremely large range of trace and minor element (Hf, Y, HREE, Th, U) compositions, which contrast with relatively simple textures and zoning patterns in zircons from a Capraia dacite. We have used a relatively simple textural classification (patchy zoning, homogenous cores, oscillatory zoning and unzoned zircon) as the basis for discussing the chemical composition and chemical variation within zircons from the Monte Capanne pluton. Based on these data and other works (Dini et al. 2004 in Lithos 78:101-118, 2004), it is inferred that mixing between metaluminous and peraluminous melts occurred early in the evolution of the Monte Capanne magma chamber. In particular, mixing was responsible for the development of the patchy-zoning texture in the zircon cores, which was associated with reactions between other accessory phases (including monazite, apatite, allanite), which we infer to have significantly affected the Th distribution in zircon. Zircons from the MC pluton displaying "homogeneous cores" have chemical affinities with zircons in the coeval Capraia volcanic system, consistent with the participation of a Capraia-like mantle end-member during mixing. Further zircon growth in the MC pluton produced the oscillatory zoning texture, which records both long-term (crystal fractionation) and transient (recharge with both silicic and mafic magmas) events in a hybrid magma chamber. It is inferred that Hf and the Th/U ratio cannot be used alone to infer magmatic processes due to their dependency on temperature, nor are they a diagnostic feature of xenocrystic grains. This study shows that zircon chemistry coupled with detailed textural analysis can provide a powerful tool to elucidate the complex evolution of a magma system. © 2009 Springer-Verlag.

Friede T.,University of Gottingen | Parsons N.,University of Warwick | Stallard N.,University of Warwick
Statistics in Medicine | Year: 2012

Growing interest in personalised medicine and targeted therapies is leading to an increase in the importance of subgroup analyses. If it is planned to view treatment comparisons in both a predefined subgroup and the full population as co-primary analyses, it is important that the statistical analysis controls the familywise type I error rate. Spiessens and Debois (Cont. Clin. Trials, 2010, 31, 647-656) recently proposed an approach specific for this setting, which incorporates an assumption about the correlation based on the known sizes of the different groups, and showed that this is more powerful than generic multiple comparisons procedures such as the Bonferroni correction. If recruitment is slow relative to the length of time taken to observe the outcome, it may be efficient to conduct an interim analysis. In this paper, we propose a new method for an adaptive clinical trial with co-primary analyses in a predefined subgroup and the full population based on the conditional error function principle. The methodology is generic in that we assume test statistics can be taken to be normally distributed rather than making any specific distributional assumptions about individual patient data. In a simulation study, we demonstrate that the new method is more powerful than previously suggested analysis strategies. Furthermore, we show how the method can be extended to situations when the selection is not based on the final but on an early outcome. We use a case study in a targeted therapy in oncology to illustrate the use of the proposed methodology with non-normal outcomes. © 2012 John Wiley & Sons, Ltd.

The intrinsic reactivity of 4 metallic iron materials (Fe0) was investigated in batch and column experiments. The Fe0 reactivity was characterised by the extent of aqueous fixation of in-situ leached arsenic (As). Air-homogenised batch experiments were conducted for 1 month with 10.0 g/ℓ of an As-bearing rock (ore material) and 0.0 or 5.0 g/ℓ of Fe0. Column experiments were performed for 2 and 3 months. Each dynamic experiment was made up of 2 glass columns in series. The first column contained 2.5 or 5.0 g of the ore material and the second column 0.0 or 5.0 g of a Fe0 material. Results showed no significant reactivity difference in batch studies for all 4 materials; ZVI2 was by far the most reactive material in column experiments. This observation was attributed to the relative kinetics of production of aqueous As and Fe species under the experimental conditions and their impact on the formation of a protective film on Fe0. Accordingly, no protective film could be built at the surface of the least reactive materials. The results corroborated the urgent need for unified experimental procedures to characterise Fe0 materials.

Reiners A.,University of Gottingen | Mohanty S.,Imperial College London
Astrophysical Journal | Year: 2012

Angular momentum evolution in low-mass stars is determined by initial conditions during star formation, stellar structure evolution, and the behavior of stellar magnetic fields. Here we show that the empirical picture of angular momentum evolution arises naturally if rotation is related to magnetic field strength instead of to magnetic flux and formulate a corrected braking law based on this. Angular momentum evolution then becomes a strong function of stellar radius, explaining the main trends observed in open clusters and field stars at a fewGyr: the steep transition in rotation at the boundary to full convection arises primarily from the large change in radius across this boundary and does not require changes in dynamo mode or field topology. Additionally, the data suggest transient core-envelope decoupling among solar-type stars and field saturation at longer periods in very low mass stars. For solar-type stars, our model is also in good agreement with the empirical Skumanich law. Finally, in further support of the theory, we show that the predicted age at which low-mass stars spin down from the saturated to unsaturated field regimes in our model corresponds remarkably well to the observed lifetime of magnetic activity in these stars. © 2012. The American Astronomical Society. All rights reserved.

Meinhold G.,University of Gottingen | Kostopoulos D.K.,National and Kapodistrian University of Athens
Tectonophysics | Year: 2013

The Circum-Rhodope Belt (CRB) sensu stricto comprises low-grade metamorphosed Triassic and Jurassic sedimentary rocks fringing the high-grade metamorphic rocks of the Serbo-Macedonian and Rhodope massifs in northern Greece. Main outcrops occur in the easternmost part of the Vardar suture zone in the Chalkidiki peninsula (Melissochori Formation; formerly Svoula flysch) and in Thrace (Makri unit and Melia Formation). The tectonostratigraphic relationship between the CRB and the high-grade metamorphics has been the subject of long discussions. Older interpretations maintain that the CRB represents the original Mesozoic stratigraphic cover of the Serbo-Macedonian crystalline basement, whereas later revisions propose the existence of two distinct greenschist-facies Mesozoic metasedimentary units: an eastern unit related to the development of a Jurassic black shale basin north of the Rhodope, and a western unit related to the development of an olistostromic flysch in the Cretaceous. Here we present a critical re-evaluation of the CRB with regard to its age, provenance, and tectonic setting based on novel geochemical and isotopic data.The Makri unit and the Melissochori Formation belong to the CRB proper and were deposited in proximity to Carboniferous-Early Permian igneous basement rocks (Pelagonia / Strandja / Thracia Terrane) in latest Triassic and Jurassic times, as shown by a prominent detrital zircon age population of 350-290. Ma. By contrast, the Melia Formation is unrelated to the CRB and was deposited in a foreland basin in front of a metamorphic nappe pile with Rhodopean affinities in the early Cretaceous, as shown by a prominent detrital zircon age population of 315-285. Ma and xenocrysts of ~. 550. Ma and ~. 450. Ma. Thus, the commonly accepted CRB concepts have to be revisited. All units have been tectonically juxtaposed to their present location during Balkan and Alpine orogenic processes. © 2012 Elsevier B.V.

Neudecker M.,Max Planck Institute for Dynamics and Self-Organization | Ulrich S.,University of Gottingen | Herminghaus S.,Max Planck Institute for Dynamics and Self-Organization | Schroter M.,Max Planck Institute for Dynamics and Self-Organization
Physical Review Letters | Year: 2013

We prepare packings of frictional tetrahedra with volume fractions φ ranging from 0.469 to 0.622 using three different experimental protocols under isobaric conditions. Analysis via x-ray microtomography reveals that the contact number Z grows with φ, but does depend on the preparation protocol. While there exist four different types of contacts in tetrahedra packings, our analysis shows that the edge-to-face contacts contribute about 50% of the total increase in Z. The number of constraints per particle C increases also with φ and even the loosest packings are strongly hyperstatic, i.e., mechanically overdetermined with C approximately twice the degrees of freedom each particle possesses. © 2013 American Physical Society.

Gavara N.,U.S. National Institutes of Health | Chadwick R.S.,U.S. National Institutes of Health | Chadwick R.S.,University of Gottingen
Nature Nanotechnology | Year: 2012

The atomic force microscope can detect the mechanical fingerprints of normal and diseased cells at the single-cell level under physiological conditions. However, atomic force microscopy studies of cell mechanics are limited by the 'bottom effect' artefact that arises from the stiff substrates used to culture cells. Because cells adhered to substrates are very thin, this artefact makes cells appear stiffer than they really are. Here, we show an analytical correction that accounts for this artefact when conical tips are used for atomic force microscope measurements of thin samples. Our bottom effect cone correction (BECC) corrects the Sneddon's model, which is widely used to measure Young's modulus, E. Comparing the performance of BECC and Sneddon's model on thin polyacrylamide gels, we find that although Sneddon's model overestimates E, BECC yields E values that are thickness-independent and similar to those obtained on thick regions of the gel. The application of BECC to measurements on live adherent fibroblasts demonstrates a significant improvement on the estimation of their local mechanical properties. © 2012 Macmillan Publishers Limited. All rights reserved.

Gerwick E.,University of Gottingen
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

We derive a recursion relation for the analytic leading logarithmic coefficients of a final state gluon cascade. We demonstrate the potential of our method by analytically computing the rate coefficients for the emission of up to 80 gluons in both the exclusive-kt (Durham) and generalized inclusive-kt class of jet algorithms. There is a particularly simple form for the ratios of resolved coefficients. We suggest potential applications for our method including the efficient generation of shower histories. © 2013 American Physical Society.

Hegerfeldt G.C.,University of Gottingen
Physical Review Letters | Year: 2013

A remarkably simple result is derived for the minimal time Tminâ ¡ required to drive a general initial state to a final target state by a Landau-Zener-type Hamiltonian or, equivalently, by time-dependent laser driving. The associated protocol is also derived. A surprise arises for some states when the interaction strength is bounded by a constant c. Then, for large c, the optimal driving is of type bang-off-bang and for increasing c one recovers the unconstrained result. However, for smaller c the optimal driving can suddenly switch to bang-bang type. We discuss the notion of quantum speed limit time. © 2013 American Physical Society.

On the plateau of the Göttingen Forest, an area of 12 ha of a ca. 145-yr-old species-rich submontane calciphytic beech forest (Hordelymo-Fagetum lathyretosum) was fenced for an ecosystem research project in 1980. Within this area a large transect (GT) of 2.81 ha with 281 10x10 m quadrats has been laid out as a permanent plot to study natural dynamics. From 1981 to 2011 every 10 years flora and vegetation have been recorded in detail (vertical structure, estimate of cover degree of all species in %, vegetation mapping). The results over the three decades are presented in tables of herb layer composi-tion, as well as quantitative distribution maps of selected species and vegetation maps. Already within the first decade a shrub layer mainly of young trees has developed in parts of the transect. Some chan-ges in the herb layer were observed. A frequency table with all 83 species found within 30 years (Ta-ble 1) shows many plants (33) with decreasing tendency besides a stock of constant species. Allium ursinum, Cardamine bulbifera, Dryopteris carthusiana, Hedera helix, and Neottia nidus-avis were the only species showing a pronounced increase. Different types of single species dominance or mixture were mapped out, with the key species Aconitum lycoctonum, Allium ursinum, Anemone nemorosa, and Mercurialis perennis.-For a long time the antagonism of Allium (distinct increase) and Mercurialis (strong decrease) was particularly striking, resulting in a strong increase of the Allium ursinum domi-nance type within the three decades. While on the microscale of quadrats a pronounced change of the floristic composition could be recognized, on the mesoscale of the total stand floristic constancy could also be found.-The discussion reviews possible causes and interpretations for the ascertained changes. Apart from local causes such as fencing and competitive power of Allium ursinum, comparison with the literature yields some more global trends. For a long time deciduous forests with no or negligible silvi-cultural treatment have undergone increasing canopy closure, leading to a shadier and more humid microclimate. Since some decades nutrient-demanding species may have benefitted from nitrogen deposition. Within the last two decades increasing effects of global warming such as a prolonged grow-ing season have been observed. As a new phenomenon the dieback of ash by fungal attack has been described.

Guerdane M.,Karlsruhe Institute of Technology | Teichler H.,University of Gottingen | Nestler B.,Karlsruhe Institute of Technology
Physical Review Letters | Year: 2013

We illustrate for a solid-liquid interface how local atomic order in a metallic melt (NiZr) transforms into a massive in-plane ordering at the surface of a crystal (bcc Zr) when commensurability is given between the solute-centered clusters of the melt and the periodic potential of the crystalline surface for a given orientation. Linking molecular dynamics simulation to phase-field modeling allows us to estimate quantitatively the influence of the surface effect on the growth kinetics. This study sheds new light on the relation between the undercooling ability (e.g., in the case of glass-forming alloys) and the pronounced local order in the melt. © 2013 American Physical Society.

The analysis of intrathecal IgG, IgA and IgM synthesis in cerebrospinal fluid (CSF) and evaluation in combined quotient diagrams provides disease-related patterns. The compilation with complementary parameters (barrier function, i.e., CSF flow rate, cytology, lactate, antibodies) in a cumulative CSF data report allows a knowledge-based interpretation and provides analytical and medical plausibility for the quality assessment in CSF laboratories. The diagnostic relevance is described for neurological and psychiatric diseases, for which CSF analysis can’t be replaced by other diagnostic methods without loss of information. Dominance of intrathecal IgM, IgA or three class immune responses give a systematic approach for Facial nerve palsy, Neurotrypanosomiasis, Opportunistic diseases, lymphoma, Neurotuberculosis, Adrenoleucodystrophy or tumor metastases. Particular applications consider the diagnostic power of the polyspecific antibody response (MRZ-antibodies) in multiple sclerosis, a CSF-related systematic view on differential diagnostic of psychiatric diseases and the dynamics of brainderived compared to blood-derived molecules in CSF for localization of paracytes. © 2016, Associacao Arquivos de Neuro-Psiquiatria. All rights reserved.

Krott M.,University of Gottingen
Forest Policy and Economics | Year: 2012

The impact of analytical research on the political process is analyzed here from the view point of stakeholders in forest policy. The interests and actions of stakeholders are described based on political theory and are illustrated using examples from 25. years of research in forest policy and consulting. The value of the knowledge produced by a model of analytical research is dependent upon its salience, credibility and legitimacy. Due to the political process of knowledge transfer, strong stakeholders can achieve a high level of salience for their interests and thus misuse analytical arguments for ideological legitimacy. To address this problem, the proper use of analytical knowledge can be supported by four strategies. First, internal allies can use analytical science to persuade other stakeholders to accept specific results. Such behavior produces scientific, rational actions, even if consensus is absent and the results are biased. Second, external allies can force other stakeholders to make use of analytical science to demonstrate that they have carefully considered scientific findings, whatever they may be. Third, political learning means that the unpredictable results of analytical science can be surprising, even to powerful stakeholders, thereby inciting learning effects. Fourth, political integration is useful for identifying the limits of analytical knowledge and adding to other sources of knowledge. These four strategies prove that even if stakeholders always dominate knowledge transfer, strictly separating analytical research from the valuations and/or direct interventions of stakeholders may bring some analytical rationality to the practical use of knowledge. These options encourage the promotion of an analytical-scientific model, even if it is often ideologically misused by powerful stakeholders. Moreover, properly used analytical research can speak truth not to power but within power processes. © 2010 Elsevier B.V.

The Late Cretaceous echinoid genus Micraster (irregular echinoids, Spatangoida) is one of the most famous examples of a continuous evolutionary lineage in invertebrate palaeontology. The influence of the environment on the phenotype, however, was not tested so far. This study analyses differences in phenotypical variations within three populations of Micraster (Gibbaster) brevis from the early Coniacian, two from the Münsterland Cretaceous Basin (Germany) and one from the North Cantabrian Basin (Spain). The environments of the Spanish and the German sites differed by their sedimentary characteristics, which are generally a crucial factor for morphological adaptations in echinoids. Most of the major phenotypical variations (position of the ambitus, periproct and development of the subanal fasciole) among the populations can be linked to differences in their host sediments. These phenotypic variations are presumed to be an expression of phenotpic plasticiy, which has not been considered in Micraster in previous studies. Two populations (Erwitte area, Germany; Liencres area, Spain) were tested for stochastic variation (fluctuating asymmetry) due to developmental instability, which was present in all studied traits. However, differences in the amount of fluctuating asymmetry between both populations were recognised only in one trait (amount of pore pairs in the anterior paired petals). The results strengthen previous assumptions on ecophenotypic variations in Micraster. © 2016 Nils Schlüter. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Zeisberg M.,University of Gottingen | Kalluri R.,University of Houston
Clinical Journal of the American Society of Nephrology | Year: 2015

Long overlooked as the virtual compartment and then strictly characterized through descriptive morphologic analysis, the renal interstitium has finally been associated with function. With identification of interstitial reninand erythropoietin-producing cells, the most prominent endocrine functions of the kidney have now been attributed to the renal interstitium. This article reviews the functional role of renal interstitium. © 2015 by the American Society of Nephrology.

In literature on Natural Resource Management related policies in Africa and Cameroon in particular, Colonial heritage was defined and identified. The question of this paper is whether "community forestry" which promotes giving back the forest to people breaks with this tradition. The key elements of Colonial heritage in resource management were deduced from literature. Based on these benchmarks the program and practice of community forestry in Cameroon were evaluated. Data about community forestry in Cameroon was collected in 10 selected communities in 2009/10. Today in practice community forestry favors techno-scientific knowledge about the forest, separate nature from human life, is a bureaucratic controlled engagement with nature and is aimed to make nature and people productive. The benchmark identifies a strong Colonial heritage within community forestry in Cameroon and questions whether the aim of including the local people in forest management, correcting their previous exclusion by the Colonial policy in the management of their forest resources, thus, the self determined life of people within the forest can be reached. © 2011 Elsevier B.V.

Giebel B.,University of Duisburg - Essen | Wodarz A.,University of Gottingen
Current Biology | Year: 2012

During Drosophila sensory organ precursor cell development, Numb segregates asymmetrically and functions as a cell fate determinant. Recent work now demonstrates in vivo that Numb inactivates Notch by promoting its endocytosis. © 2012 Elsevier Ltd. All rights reserved.

Shiraishi F.,University of Gottingen | Shiraishi F.,Hiroshima University
Geochimica et Cosmochimica Acta | Year: 2012

Chemical conditions favoring photosynthesis-induced CaCO 3 precipitation (PCP) was examined to provide basic knowledge for understanding ancient ocean chemistry that enabled microbial carbonate formation. First, numerical simulations were conducted to examine the property of photosynthetic increase in CaCO 3 saturation state (ΔΩ), an indicator for PCP introduced by previous studies. These simulations revealed that ΔΩ attained a high value at high Ca 2+ concentration, low ionic strength, and optimum pH and dissolved inorganic carbon (DIC) where a low-DIC effect and CO 2/CO 3 2- buffering were insignificant. Second, microelectrode measurements were conducted using cyanobacteria-dominated stromatolite to examine the property of actual PCP. Although Ca 2+ concentration and ionic strength similarly affected actual PCP, the influences of pH and DIC were quite different from what was expected from simulations: significant PCP occurred even at high DIC (up to ~300mmolL -1) where the ΔΩ increase was suppressed by CO 2/CO 3 2- buffering. Instead, actual PCP reflected the photosynthetically achieved saturation state (Ω aft), which is the sum of ΔΩ and initial saturation state (Ω bef). Thus, the chemical conditions favoring PCP is an optimum pH-DIC condition where ΔΩ achieves a high value and/or a high pH-DIC condition where Ω bef achieves a high value, in addition to a sufficiently high Ca 2+ concentration and low ionic strength. The microelectrode measurements also revealed that the photosynthetic pH increase did not always reflect the occurrence and significance of PCP. © 2011 Elsevier Ltd.

Sheldrick G.M.,University of Gottingen
Acta Crystallographica Section A: Foundations of Crystallography | Year: 2015

The new computer program SHELXT employs a novel dual-space algorithm to solve the phase problem for single-crystal reflection data expanded to the space group P1. Missing data are taken into account and the resolution extended if necessary. All space groups in the specified Laue group are tested to find which are consistent with the P1 phases. After applying the resulting origin shifts and space-group symmetry, the solutions are subject to further dual-space recycling followed by a peak search and summation of the electron density around each peak. Elements are assigned to give the best fit to the integrated peak densities and if necessary additional elements are considered. An isotropic refinement is followed for non-centrosymmetric space groups by the calculation of a Flack parameter and, if appropriate, inversion of the structure. The structure is assembled to maximize its connectivity and centred optimally in the unit cell. SHELXT has already solved many thousand structures with a high success rate, and is optimized for multiprocessor computers. It is, however, unsuitable for severely disordered and twinned structures because it is based on the assumption that the structure consists of atoms. © 2015 International Union of Crystallography.

Kieser M.,University of Heidelberg | Friede T.,University of Gottingen | Gondan M.,University of Heidelberg
Statistics in Medicine | Year: 2013

In drug development, it is well accepted that a successful study will demonstrate not only a statistically significant result but also a clinically relevant effect size. Whereas standard hypothesis tests are used to demonstrate the former, it is less clear how the latter should be established. In the first part of this paper, we consider the responder analysis approach and study the performance of locally optimal rank tests when the outcome distribution is a mixture of responder and non-responder distributions. We find that these tests are quite sensitive to their planning assumptions and have therefore not really any advantage over standard tests such as the t-test and the Wilcoxon-Mann-Whitney test, which perform overall well and can be recommended for applications. In the second part, we present a new approach to the assessment of clinical relevance based on the so-called relative effect (or probabilistic index) and derive appropriate sample size formulae for the design of studies aiming at demonstrating both a statistically significant and clinically relevant effect. Referring to recent studies in multiple sclerosis, we discuss potential issues in the application of this approach. © 2012 John Wiley & Sons, Ltd.

Ecker O.,International Food Policy Research Institute | Qaim M.,University of Gottingen
World Development | Year: 2011

Widespread malnutrition in developing countries calls for appropriate strategies, presupposing good knowledge about nutritional impacts of policies. Little previous work has been carried out in this direction, especially with respect to micronutrients. We use representative household data from Malawi and develop a demand systems approach to estimate income and price elasticities of food demand and nutrient consumption. These estimates are applied for policy simulations. Given multiple nutritional deficiencies, income-related policies are better suited than price policies to improve nutrition. While consumer price subsidies for maize improve calorie and mineral consumption, they can worsen vitamin consumption in urban areas. © 2010 Elsevier Ltd.

In materials science or applied crystallography, X-ray diffraction represents a versatile and useful method with which one can obtain the orientation of single crystals or even the texture of a polycrystalline material. When the investigated sample consists of many phases, or phases of low symmetry, it becomes difficult to measure pole figures from single diffraction peaks. A combined Rietveld-texture analysis with the program MAUD is perfectly suitable to deal with conditions of overlapping diffraction peaks, including those arising from different phases. Even though nearly no alternative to MAUD exists, it is not always easy to use. The input of a file series of two-dimensional diffraction images, for example from a texture measurement, can be time consuming since each individual image must be loaded manually, and only the newest beta version of MAUD allows semi-automated file input. The new program input4MAUD, which is presented in this paper, offers a much more efficient way to automate both single and batch file series input into MAUD as well as the preparation of basic batch refinements with MAUD. input4MAUD is written in Visual C++ and is currently available as a 32-bit statically compiled binary executable file for Windows. © 2014 International Union of Crystallography.

Giessen L.,University of Gottingen
Allgemeine Forst- und Jagdzeitung | Year: 2011

This article aims at reviewing recently reported concrete empirical factors influencing policy change, including conceptions of policy change as the dependent variable. It further aims at developing a set of criteria for assessing the usefulness of selecting these explanatory factors in any given research project. Based on a literature review a body of articles is identified which provides concrete empirical factors as independent variables explaining policy change. These explanatory factors are clustered and positioned in broader theories of the policy sciences. Subsequently a set of criteria is developed for assessing the usefulness of selecting independent variables in a given research process. These criteria then are applied to the analytical framework developed by SOTIROV et al. (in this issue) in order to briefly illustrate its usefulness in their research project environment. The article closes with conclusions for researchers on the theoretical and methodological choices to be made when developing their own analytical frameworks as well as with an outlook on fruitful paths for future research on policy change.

Wenger O.S.,University of Gottingen
Chemistry - A European Journal | Year: 2011

Proton-coupled electron transfer (PCET) is of fundamental importance for small-molecule activation processes, such as water splitting, CO 2-reduction, or nitrogen fixation. Ideally, energy-rich molecules such as H 2, CH 3OH, or NH 3 could be generated artificially using (solar) light as an energy input. In this context, PCETs originating directly from electronically excited states play a crucial role. A variety of transition-metal complexes have been used recently for fundamental investigations of this important class of reactions, and the key findings of these studies are reviewed in this article. The present minireview differs from other reviews on the subject of PCET in that it focuses specifically on reactions occurring directly from electronically excited states. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Kleijn D.,Wageningen University | Rundlof M.,Lund University | Rundlof M.,Swedish University of Agricultural Sciences | Scheper J.,Wageningen University | And 2 more authors.
Trends in Ecology and Evolution | Year: 2011

Biodiversity continues to decline, despite the implementation of international conservation conventions and measures. To counteract biodiversity loss, it is pivotal to know how conservation actions affect biodiversity trends. Focussing on European farmland species, we review what is known about the impact of conservation initiatives on biodiversity. We argue that the effects of conservation are a function of conservation-induced ecological contrast, agricultural land-use intensity and landscape context. We find that, to date, only a few studies have linked local conservation effects to national biodiversity trends. It is therefore unknown how the extensive European agri-environmental budget for conservation on farmland contributes to the policy objectives to halt biodiversity decline. Based on this review, we identify new research directions addressing this important knowledge gap. © 2011 Elsevier Ltd.

Zielke S.,University of Gottingen
European Journal of Marketing | Year: 2010

Purpose: The purpose of this paper is to analyse how five price image dimensions influence shopping intentions for different store formats. Design/methodology/approach: In total, 306 espondents evaluated three stores from a list of 18 retailers on a multiple-item scale, resulting in 918 price-image measurements. Based on these data, a covariance structure analysis in Mplus analyses the direct and indirect impact of five price image dimensions on shopping intentions. A multiple group analysis identifies differences in the effects between store formats. Findings: The impact of image dimensions differs substantially between store formats. For discount stores, value for money is by far the most important image dimension. For supermarkets, price level and value are equally important, but price perceptibility and price processibility are also relevant. For organic food stores, value is most important, followed by price processibility and evaluation certainty. For the weekly market, price perceptibility plays a key role in explaining customers' shopping intentions. Practical implications: The results carry several implications for retail pricing practice, as they indicate that retailers should not focus exclusively on price level competition. Depending on the store format, retailers should attach importance to the price image dimensions in varying degrees. Originality/value: The study contributes to the literature by: advancing price-image measurement; modelling direct effects on shopping intentions; analysing a number of different indirect effects in an integrated model; and taking the moderating effects of store format into account. © Emerald Group Publishing Limited.

Yu X.,University of Gottingen | Abler D.,Pennsylvania State University
China Economic Review | Year: 2014

Official agricultural statistics for China are subject to major inconsistencies and have long been questioned by researchers. The major problem with Chinese meat statistics is that reported meat supply is far greater than consumption, and this is particularly true for pork. Factors contributing to the gap between pork supply and consumption include production over-reporting, loss and waste in the pork supply chain, pork consumed away from home (FAFH), and a mismatch in the Chinese rural household survey between food and mouths (i.e. migrant workers and boarding students who are counted as rural household members but live in urban areas for much of the year). Our estimates indicate that over-reporting of pork production has declined substantially since 2003, but it is still significant and is the largest contributor to the gap between reported supply and consumption. Our estimates also indicate that pork consumption is significantly under-estimated because of FAFH and the rural mismatch between food and mouths. Reforms to the agricultural statistical system should be considered that increase the incentives to report accurate production statistics. Statistics are currently based on reports from local officials who have incentives to inflate production figures so as to improve their performance reviews and prospects for promotion, or they are overseen by local statistical personnel appointed by local governments. © 2014 Elsevier Inc.

Straube S.,University of Gottingen
The Cochrane database of systematic reviews | Year: 2013

This review is an update of a review first published in Issue 2, 2003, which was substantially updated in Issue 7, 2010. The concept that many neuropathic pain syndromes (traditionally this definition would include complex regional pain syndromes (CRPS)) are "sympathetically maintained pains" has historically led to treatments that interrupt the sympathetic nervous system. Chemical sympathectomies use alcohol or phenol injections to destroy ganglia of the sympathetic chain, while surgical ablation is performed by open removal or electrocoagulation of the sympathetic chain or by minimally invasive procedures using thermal or laser interruption. To review the evidence from randomised, double blind, controlled trials on the efficacy and safety of chemical and surgical sympathectomy for neuropathic pain, including complex regional pain syndrome. Sympathectomy may be compared with placebo (sham) or other active treatment, provided both participants and outcome assessors are blind to treatment group allocation. On 2 July 2013, we searched CENTRAL, MEDLINE, EMBASE, and the Oxford Pain Relief Database. We reviewed the bibliographies of all randomised trials identified and of review articles and also searched two clinical trial databases, ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform, to identify additional published or unpublished data. We screened references in the retrieved articles and literature reviews and contacted experts in the field of neuropathic pain. Randomised, double blind, placebo or active controlled studies assessing the effects of sympathectomy for neuropathic pain and CRPS. Two review authors independently assessed trial quality and validity, and extracted data. No pooled analysis of data was possible. Only one study satisfied our inclusion criteria, comparing percutaneous radiofrequency thermal lumbar sympathectomy with lumbar sympathetic neurolysis using phenol in 20 participants with CRPS. There was no comparison of sympathectomy versus sham or placebo. No dichotomous pain outcomes were reported. Average baseline scores of 8-9/10 on several pain scales fell to about 4/10 initially (1 day) and remained at 3-5/10 over four months. There were no significant differences between groups, except for "unpleasant sensation", which was higher with radiofrequency ablation. One participant in the phenol group experienced post sympathectomy neuralgia, while two in the radiofrequency group and one in the phenol group complained of paraesthesia during needle positioning. All participants had soreness at the injection site. The practice of surgical and chemical sympathectomy for neuropathic pain and CRPS is based on very little high quality evidence. Sympathectomy should be used cautiously in clinical practice, in carefully selected patients, and probably only after failure of other treatment options. In these circumstances, establishing a clinical register of sympathectomy may help to inform treatment options on an individual patient basis.

Hardeland R.,University of Gottingen
Current Neuropharmacology | Year: 2010

The metabolism of melatonin in the central nervous system is of interest for several reasons. Melatonin enters the brain either via the pineal recess or by uptake from the blood. It has been assumed to be also formed in some brain areas. Neuroprotection by melatonin has been demonstrated in numerous model systems, and various attempts have been undertaken to counteract neurodegeneration by melatonin treatment. Several concurrent pathways lead to different products. Cytochrome P450 subforms have been demonstrated in the brain. They either demethylate melatonin to N-acetylserotonin, or produce 6-hydroxymelatonin, which is mostly sulfated already in the CNS. Melatonin is deacetylated, at least in pineal gland and retina, to 5-methoxytryptamine. N1-acetyl-N2-formyl-5-methoxykynuramine is formed by pyrrole-ring cleavage, by myeloperoxidase, indoleamine 2,3-dioxygenase and various non-enzymatic oxidants. Its product, N1-acetyl-5-methoxykynuramine, is of interest as a scavenger of reactive oxygen and nitrogen species, mitochondrial modulator, downregulator of cyclooxygenase-2, inhibitor of cyclooxygenase, neuronal and inducible NO synthases. Contrary to other nitrosated aromates, the nitrosated kynuramine metabolite, 3-acetamidomethyl-6-methoxycinnolinone, does not re-donate NO. Various other products are formed from melatonin and its metabolites by interaction with reactive oxygen and nitrogen species. The relative contribution of the various pathways to melatonin catabolism seems to be influenced by microglia activation, oxidative stress and brain levels of melatonin, which may be strongly changed in experiments on neuroprotection. Many of the melatonin metabolites, which may appear in elevated concentrations after melatonin administration, possess biological or pharmacological properties, including N-acetylserotonin, 5-methoxytryptamine and some of its derivatives, and especially the 5-methoxylated kynuramines. © 2010 Bentham Science Publishers Ltd.

Nikiforov G.B.,University of Ottawa | Roesky H.W.,University of Gottingen | Koley D.,Indian Institute of Science
Coordination Chemistry Reviews | Year: 2013

A significant amount of information regarding the synthesis, reactivity, and catalytic activity of titanium fluoride complexes is available in the literature. However, the reports are mostly nonsystematic and spread over a large number of specific journals. An attempt is made to collect and organize all available information. Emphasis is given on work published after 1990 with links to the previous reviews, but earlier work is also included if no systematic report was done before.Published synthetic methods to access titanium fluoride complexes are covered in the present review, as well as the properties and reactivity of titanium fluoride complexes. In particular, the behavior of TiF4 in non-aqueous solvents, as well as the interaction of TiF4 with neutral and charged ligands in non-aqueous solvents is reviewed. All published tetrafluoride complexes TiF4L2 (L - neutral ligand) are presented. Mixed chloro and fluoro titanium complexes supported by neutral ligands, their preparation, and isomerism are surveyed. DFT calculations were performed to estimate the relative basicities of molecular ligands in titanium fluoride complexes as well as the relative stability of fluoride bridged titanium complexes.The reactivity of heterometallic titanium-alkali metal, titanium-alkaline earth metal fluoride complexes, the interaction of titanium fluoride complexes with silicon substrates, and the reactivity of titanium complexes toward organofluorine compounds are presented later in the review.Titanium fluoride complexes have found numerous applications in organic synthesis, and in many cases, the fluoride complex shows better performance than do complexes supported by other types of ligands. Organotitanium fluoride complexes show antitumor activity, and their values of cytotoxicity are comparable to that of the "gold standard" cisplatin. © 2013 Elsevier B.V.

Jerabek P.,University of Marburg | Roesky H.W.,University of Gottingen | Bertrand G.,University of California at San Diego | Frenking G.,University of Marburg
Journal of the American Chemical Society | Year: 2014

Quantum chemical calculations using density functional theory have been carried out for the cyclic (alkyl)(amino)carbene (cAAC) complexes of the group 11 atoms [TM(cAAC)2] (TM = Cu, Ag, Au) and their cations [TM(cAAC)2]+. The nature of the metal-ligand bonding was investigated with the charge and energy decomposition analysis EDA-NOCV. The calculations show that the TM-C bonds in the charged adducts [TM(cAAC)2]+ are significantly longer than in the neutral complexes [TM(cAAC)2], but the cations have much higher bond dissociation energies than the neutral molecules. The intrinsic interaction energies δEint in [TM(cAAC)2]+ take place between TM+ in the 1S electronic ground state and (cAAC)2. In contrast, the metal-ligand interactions in [TM(cAAC)2] involve the TM atoms in the excited 1P state yielding strong TM p(π) → (cAAC)2 π backdonation, which is absent in the cations. The calculations suggest that the cAAC ligands in [TM(cAAC)2] are stronger π acceptors than σ donors. The trends of the intrinsic interaction energies and the bond dissociation energies of the metal-ligand bonds in [TM(cAAC)2] and [TM(cAAC)2]+ give the order Au > Cu > Ag. Calculations at the nonrelativistic level give weaker TM-C bonds, particularly for the gold complexes. The trend for the bond strength in the neutral and charged adducts without relativistic effects becomes Cu > Ag > Au. The EDA-NOCV calculations suggest that the weaker bonds at the nonrelativistic level are mainly due to stronger Pauli repulsion and weaker orbital interactions. The NBO picture of the C-TM-C bonding situation does not correctly represent the nature of the metal-ligand interactions in [TM(cAAC)2]. © 2014 American Chemical Society.

Zeuch T.,University of Gottingen | Buck U.,Max Planck Institute for Dynamics and Self-Organization
Chemical Physics Letters | Year: 2013

Neutral, sodium doped clusters feature special properties related to solvated electron formation which allow for a wide range of applications. In case of water, methanol and ethanol - but not for ammonia - the evolution of the ionization energy stops at small cluster sizes, reaching values similar to binding energies of solvated electrons in the liquid phase. Because of the appreciable lowering of the ionization energy, their photoionization can be performed free of fragmentation by standard lasers. This provides a very effective method for detection and, in combination with infrared excitation, for taking OH-stretch spectra of size selected, neutral clusters. © 2013 Elsevier B.V. All rights reserved.

Neesse A.,University of Gottingen | Algul H.,TU Munich | Tuveson D.A.,Pancreatic Cancer Research Laboratory | Gress T.M.,University of Marburg
Gut | Year: 2015

Pancreatic ductal adenocarcinoma (PDA) exhibits one of the poorest prognosis of all solid tumours and poses an unsolved problem in cancer medicine. Despite the recent success of two combination chemotherapies for palliative patients, the modest survival benefits are often traded against significant side effects and a compromised quality of life. Although the molecular events underlying the initiation and progression of PDA have been intensively studied and are increasingly understood, the reasons for the poor therapeutic response are hardly apprehended. One leading hypothesis over the last few years has been that the pronounced tumour microenvironment in PDA not only promotes carcinogenesis and tumour progression but also mediates therapeutic resistance. To this end, targeting of various stromal components and pathways was considered a promising strategy to biochemically and biophysically enhance therapeutic response. However, none of the efforts have yet led to efficacious and approved therapies in patients. Additionally, recent data have shown that tumour-associated fibroblasts may restrain rather than promote tumour growth, reinforcing the need to critically revisit the complexity and complicity of the tumour-stroma with translational implications for future therapy and clinical trial design.

Grip2.1 is a conserved PDZ-domain protein with a function in the context of primordial germ cell development and migration in Xenopus embryos. Its mRNA is maternally supplied and found to be associated with the germ plasm, located at the tip of the vegetal cortex in Xenopus oocytes. Here, we demonstrate that the 3'-UTR of XGrip2.1 contains a 211 nucleotide RNA signal sequence that promotes localization to the mitochondrial cloud via the early localization pathway upon injection into stage I oocytes. The same element is also capable of using the late transport pathway if injected into stage III/IV oocytes. In vitro protein interaction studies reveal binding to ElrA/B, Vg1RBP and VgRBP60, proteins that have previously been associated with the vegetal localization machinery. Mutational interference with Vg1RBP and VgRBP60 binding severely reduces early and late localization activity. Selective interference with Vg1RBP binding significantly reduces late localization while having only a mild effect on localization to the mitochondrial cloud, indicating that the signal sequences and protein machinery required for early and late pathway localization though overlapping are not identical.

Kiel S.,University of Gottingen | Amano K.,Joetsu University of Education
Journal of Paleontology | Year: 2013

Bathymodiolin mussels are a group of bivalves associated with deep-sea hydrothermal vents and other reducing deep-sea habitats, and they have a particularly rich early Cenozoic fossil record in western Washington State, U.S.A. Here we recognize six species from middle Eocene to latest Oligocene deep-water methane seep deposits in western Washington. Two of them are new: Vulcanidas? goederti from the middle Eocene Humptulips Formation and Bathymodiolus (sensu lato) satsopensis from the late Oligocene part of the Lincoln Creek Formation. Very similar to the latter but more elongate are specimens from the early Oligocene Jansen Creek Member of the Makah Formation and are identified as B. (s.l.) aff. satsopensis. Bathymodiolus (s.l.) inouei Amano and Jenkins, 2011 is reported from the Lincoln Creek Formation. Idas? olympicus Kiel and Goedert, 2007 was previously known from late Eocene to Oligocene whale and wood falls in western Washington and is here reported from Oligocene seep deposits of the Makah and Pysht Formations. Vulcanidas? goederti occurs at a seep deposit from a paleodepth possibly as great as 2000 m, suggesting that its living relative, Vulcanidas insolatus Cosel and Marshall, 2010, which lives at depths of only 150-500 m, is derived from a deep-water ancestor. The bathymodiolins in western Washington indicate that the group originated at least in the middle Eocene and underwent a first diversification in the late Eocene to Oligocene. Early ontogenetic shells of all fossil species investigated so far, including the middle Eocene Vulcanidas? goederti, reflect planktotrophic larval development indicating that this developmental mode is an ancestral trait of bathymodiolins.Copyright © 2013, The Paleontological Society.

Fischer A.,University of Gottingen | Fischer A.,German Center for Neurodegenerative Diseases
Neuropharmacology | Year: 2014

Alzheimer' s disease (AD) is the most common form of dementia causing an increasing emotional and economical burden to our societies. Although much progress has been made regarding the molecular mechanisms that underlie AD pathogenesis effective therapies are not available yet. The emerging field of neuroepigenetics has provided evidence that de-regulation of epigenetic processes play a role in AD. In this article we will critically review the primary research data that led to the hypothesis that targeting histone-modifying enzymes could be used to treat AD pathogenesis and address the question if the field is ready to translate such findings into clinical application. © 2014 Elsevier Ltd. All rights reserved.

Nauck F.,University of Gottingen
Medizinische Klinik - Intensivmedizin und Notfallmedizin | Year: 2011

Therapy decisions in the care of critically ill and dying patients in intensive care and emergency medicine must reflect probably conflicting issues of medical indications, ethics and law. This is of particular relevance when treatment preferences of patients are not known or are in contrast to those of the carers. Difficulties regarding prognostication or with determining the beginning of an irreversible dying process may also lead to treatment situations that need ethical reflection. It is recommended to tackle medico-ethical issues by discussion of the meaning of relevant terms and medico-ethical principles, analyzing the professional self-image in intensive care and emergency medicine, consideration of options of palliative medicine and by use of an ethics case consultation. © 2011 Urban & Vogel, Muenchen.

Sulieman S.,University of Khartoum | Sulieman S.,University of Gottingen | Tran L.-S.P.,RIKEN
Critical Reviews in Biotechnology | Year: 2013

Symbiotic nitrogen fixation is tightly regulated by a range of fine processes at the nodule level, over which the host plant has overall control through the whole life of the plant. The operation of this control at the nodule level is not yet fully understood, but greater knowledge will ultimately lead to a better improvement of N2 fixation through the use of crop legumes and genetic engineering of crop plants for higher performance. It has been suggested that, nodule responses to the nutritional complexity of the rhizosphere environment involve a great deal of coordination of sensing and signal transduction. This regulation can be achieved through several mechanisms, including changes in carbon metabolism, oxygen supply and/or overproduction of reactive oxygen and nitrogen species. Recently, the cycling of amino acids observed between the plant and bacteroid fractions suggests a new and important regulatory mechanism involved in nodule responses. Most of the recent transcriptional findings are consistent with the earlier biochemical and physiological reports. Current research revealed unique advances for nodule metabolism, especially on the regulation of asparagine synthetase gene expression and the control of asparagine (ASN) to N2 fixing activity. A large amount of ASN is found accumulating in the root nodules of the symbiotic plants under restricted environments, such as drought, salinity and nutrient deficiency. Exceptionally, ASN phloem feeding has resulted in an increased concentration of the ASN amide in nodules followed by a remarkable decrease in nodule activity. In this review, recent progress concerning the possible role of ASN in whole-plant-based down-regulation of symbiotic N 2 fixation will be reviewed. © 2013 Informa Healthcare USA, Inc.

Noubactep C.,University of Gottingen | Noubactep C.,Kultur und Nachhaltige Entwicklung CDD e.V.
Journal of Hazardous Materials | Year: 2011

This letter challenges the concept that the metallic iron (Fe 0) surface contributes directly to the process of micro-organism inactivation in aqueous solutions. It is shown that any antimicrobial properties of Fe 0 is related to the cycle of expansion/contraction accompanying aqueous iron corrosion. This demonstration corroborates the concept that aqueous contaminant removal in the presence of Fe 0 mostly occurs at the Fe-oxide/water interface or within the oxide-film on Fe 0. © 2011 Elsevier B.V.

Wenger O.S.,University of Gottingen
Chemical Society Reviews | Year: 2011

Phenylene oligomers represent a borderline case between very strongly π-conjugated molecular wires such as oligo-p-phenylene vinylenes and saturated molecular bridges. Even subtle chemical modifications of phenylene oligomers can therefore have a strong impact on charge transfer rates and mechanisms. On the basis of recently published selected case studies, this tutorial review discusses the key factors that affect charge transfer kinetics in phenylene oligomers with particular focus on the role of donor-bridge energy matching. Selected examples of triplet-triplet energy transfer reactions across phenylene oligomers are also discussed. © 2011 The Royal Society of Chemistry.

Strulik H.,University of Gottingen
Journal of Health Economics | Year: 2014

This paper proposes a theory for the social evolution of obesity. It considers a society in which individuals experience utility from consumption of food and non-food, the state of their health, and the evaluation of their appearance by others. The theory explains under which conditions poor persons are more prone to be overweight although eating is expensive and it shows how obesity occurs as a social phenomenon such that body mass continues to rise long after the initial cause (e.g. a lower price of food) is gone. The paper investigates the determinants of a steady state at which the median person is overweight and how an originally lean society arrives at such a steady state. Extensions of the theory towards dietary choice and the possibility to exercise in order to lose weight demonstrate robustness of the basic mechanism and provide further interesting results. © 2013 Elsevier B.V.

Bayer M.,Humboldt University of Berlin | Sommer W.,Humboldt University of Berlin | Schacht A.,University of Gottingen
Psychophysiology | Year: 2012

Event-related potentials (ERPs) revealed effects of emotional meaning on word recognition at distinguishable processing stages, in rare cases even in the P1 time range. However, the boundary conditions of these effects, such as the roles of different levels of linguistic processing or the relative contributions of the emotional valence and arousal dimensions, remain to be fully understood. The present study addresses this issue by employing two tasks of different processing demands on words that orthogonally varied in their emotional valence and arousal. Effects of emotional valence in ERPs were evident from 100ms after word onset and showed a task-insensitive processing advantage for positive words. Early posterior negativity (EPN) effects to high-arousing words were limited to the lexical decision task, corroborating recent reports that suggested that perceptual processing as reflected in the EPN might not be as automatic as previously assumed. © 2012 Society for Psychophysiological Research.

Goenner H.F.M.,University of Gottingen
Annalen der Physik (Leipzig) | Year: 2010

In recent years, by theory and observation cosmology has advanced substantially. Parameters of the concordance or ACDM cosmological model are given with unprecedented precision ("precision cosmology"). On the other hand, 95% of the matter content of the universe are of an unknown nature. This awkward situation motivates the present attempt to find cosmology's place among the (exact) natural sciences. Due to its epistemic and methodical particularities, e.g., as a mathematized historical science, cosmology occupies a very special place. After going through some of the highlights of cosmological modeling, the conclusion is reached that knowledge provided by cosmological modeling cannot be as explicative and secure as knowledge gained by laboratory physics. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Barke A.,University of Gottingen | Nyarko S.,Albert Ludwigs University of Freiburg | Klecha D.,University of Bern
Social Psychiatry and Psychiatric Epidemiology | Year: 2011

Purpose Stigma is a frequent accompaniment of mental illness leading to a number of detrimental consequences. Most research into the stigma connected to mental illness was conducted in the developed world. So far, few data exist on countries in sub-Saharan Africa and no data have been published on population attitudes towards mental illness in Ghana. Even less is known about the stigma actually perceived by the mentally ill persons themselves. Method A convenience sample of 403 participants (210 men, mean age 32.4 ± 12.3 years) from urban regions in Accra, Cape Coast and Pantang filled in the Community Attitudes towards the Mentally Ill (CAMI) questionnaire. In addition, 105 patients (75 men, mean age 35.9 ± 11.0 years) of Ghana's three psychiatric hospitals (Accra Psychiatry Hospital, Ankaful Hospital, Pantang Hospital) answered the Perceived Stigma and Discrimination Scale. Results High levels of stigma prevailed in the population as shown by high proportions of assent to items expressing authoritarian and socially restrictive views, coexisting with agreement with more benevolent attitudes. A higher level of education was associated with more positive attitudes on all subscales (Authoritarianism, Social Restrictiveness, Benevolence and Acceptance of Community Based Mental Health Services). The patients reported a high degree of experienced stigma with secrecy concerning the illness as a widespread coping strategy. Perceived stigma was not associated with sex or age. Discussion The extent of stigmatising attitudes within the urban population of Southern Ghana is in line with the scant research in other countries in sub-Saharan Africa and mirrored by the experienced stigma reported by the patients. These results have to be seen in the context of the extreme scarcity of resources within the Ghanaian psychiatric system. Anti-stigma efforts should include interventions for mentally ill persons themselves and not exclusively focus on public attitudes. © The Author(s) 2010.

Kues U.,University of Gottingen
Fungal Biology Reviews | Year: 2015

Fungi do not have different sexes characterized by specific morphological organs but control sexual development by physiological differences defined by mating types. While other lineages in the fungal kingdom have only two distinct mating types, multiple mating types are common in the Basidiomycetes, presumably for outcomes related to enhanced outbreeding. Mating types in Basidiomycetes are determined by genes that encode two types of homeodomain transcription factors (HD genes) and by genes that encode lipopeptide pheromones and pheromone receptors (PR genes). In the tetrapolar mushroom Coprinopsis cinerea, these genes reside at two distinct loci on different chromosomes and regulate distinct steps in dikaryon formation and maintenance and fruiting body formation for sexual reproduction by controlling the expression of large sets of genes. The matA (HD) locus in C. cinerea has an estimated 160 alleles in nature, and the matB (PR) locus has 79. The respective products of both loci interact with each other in a lock-and-key manner. Proteins encoded in allelic sets of mating type genes recognize each other and interact in order to either form a functional transcription factor complex that is transported into the nucleus (matA proteins) or to initiate a pheromone response signaling cascade (matB proteins). Products encoded by the same matA or matB allele do not interact, which is crucial to the functionality of the two systems controlling sexual development. Multiple alleles of mating type genes arose in evolution through the evolution of distinct DNA sequences and the resulting encoded proteins perform the tasks of recognition and discrimination. In a second modus of multiplication, paralogous sets of HD and PR genes evolved by gene duplications and subsequent sequence diversification in order to mediate functional independency and respective allele variation. In C. cinerea, there are thus three paralogous groups of functional mating type genes at both the matA and the matB locus. Because groups of paralogous genes are freely interchangeable, only a few alleles of each of the actual gene groups (between 2 and 9 are known per group) are required to generate the large number of distinct matA and matB mating types found in nature. As deduced from the ever increasing number of genome projects, the basic principles of evolution of multiple mating types as unraveled in C. cinerea by Lorna A. Casselton and her coworkers are to different degrees also operative in other mushroom species. © 2015 The British Mycological Society.

Castorph S.,University of Gottingen
The European physical journal. E, Soft matter | Year: 2011

The size polydispersity distribution of synaptic vesicles (SVs) is characterized under quasi-physiological conditions by dynamic light scattering (DLS). Highly purified fractions of SVs obtained from rat brain still contain a small amount of larger contaminant structures, which can be quantified by DLS and further reduced by asymmetric-flow field-flow (AFFF) fractionation. The intensity autocorrelation functions g (2)(τ) recorded from these samples are analyzed by a constrained regularization method as well as by an alternative direct modeling approach. The results are in quantitative agreement with the polydispersity obtained from cryogenic electron microscopy of vitrified SVs. Next, different vesicle fusion assays based on samples composed of SVs and small unilamellar proteoliposomes with the fusion proteins syntaxin 1 and SNAP-25A are characterized by DLS. The size increase of the proteoliposomes due to SNARE-dependent fusion with SVs is quantified by DLS under quasi-physiological conditions.

Giesecke T.,University of Gottingen
Vegetation History and Archaeobotany | Year: 2014

The number of well-dated pollen diagrams in Europe has increased considerably over the last 30 years and many of them have been submitted to the European Pollen Database (EPD). This allows for the construction of increasingly precise maps of Holocene vegetation change across the continent. Chronological information in the EPD has been expressed in uncalibrated radiocarbon years, and most chronologies to date are based on this time scale. Here we present new chronologies for most of the datasets stored in the EPD based on calibrated radiocarbon years. Age information associated with pollen diagrams is often derived from the pollen stratigraphy itself or from other sedimentological information. We reviewed these chronological tie points and assigned uncertainties to them. The steps taken to generate the new chronologies are described and the rationale for a new classification system for age uncertainties is introduced. The resulting chronologies are fit for most continental-scale questions. They may not provide the best age model for particular sites, but may be viewed as general purpose chronologies. Taxonomic particularities of the data stored in the EPD are explained. An example is given of how the database can be queried to select samples with appropriate age control as well as the suitable taxonomic level to answer a specific research question. © 2013 The Author(s).

Kiel S.,University of Gottingen | Kiel S.,University of Vienna
Proceedings of the Royal Society B: Biological Sciences | Year: 2015

The origin and evolution of the faunas inhabiting deep-sea hydrothermal vents andmethane seeps have been debated for decades. These faunas rely on a local source of sulfide and other reduced chemicals for nutrition, which spawned the hypothesis that their evolutionary history is independent from that of photosynthesis- based food chains and instead driven by extinction events caused by deep-sea anoxia. Here I use the fossil record of seep molluscs to show that trends in body size, relative abundance and epifaunal/infaunal ratios track current estimates of seawater sulfate concentrations through the last 150 Myr. Furthermore, the two main faunal turnovers during this time interval coincide with major changes in seawater sulfate concentrations. Because sulfide at seeps originates mostly from seawater sulfate, variations in sulfate concentrations should directly affect the base of the food chain of this ecosystem and are thus the likely driver of the observed macroecologic and evolutionary patterns. The results imply that the methane-seep fauna evolved largely independently from developments and mass extinctions affecting the photosynthesis-based biosphere and add to the growing body of evidence that the chemical evolution of the oceans had a major impact on the evolution of marine life. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Voracek M.,University of Vienna | Voracek M.,University of Gottingen
Evolution and Human Behavior | Year: 2014

A series of meta-analyses assessed whether differentially efficacious variants (CAG and GGC repeat-length polymorphisms) of the human androgen receptor gene are associated with digit ratio (2D:4D), a widely investigated putative pointer to prenatal androgen action. Extensive literature search strategies identified a maximum of 18 samples (total N= 2909) vs. 5 samples (N= 1497) for the CAG-related vs. GGC-related meta-analyses, respectively. In contrast to a small-sample (N= 50) initial report, widely cited affirmatively in the literature, meta-analysis of the entire retrievable evidence base did not support any associations between CAG variants and right-hand, left-hand, or right-minus-left-hand 2D:4D. Effects of GGC variants on digit ratios likewise were almost exactly null. For the CAG literature, time trend analysis indicated shrinking effects among more recent studies. Both quantitative and qualitative citation analyses documented that citation bias exists in the research literature: CAG-related studies yielding larger effects were cited more frequently within the same time unit, and the initial, unreplicated report continued to be cited frequently and mostly solely as well as confirmatively, while non-replications were cited much less often. The meta-analytical null findings, along with several further strands of evidence consistent with these, undermine one validity claim for 2D:4D as a retrospective pointer to prenatal testosterone action. Discussed are alternative interpretations of the evidence and avenues for future research. © 2014 Elsevier Inc.

Kaatze U.,University of Gottingen
Journal of Physical Chemistry B | Year: 2011

To study the kinetics of surfactant systems below, at, and above the critical micelle concentration cmc, broad-band ultrasonic spectra of short-chain ionic surfactant solutions are evaluated. Within the measurement frequency range from 100 kHz to 4.6 GHz the spectra reveal a relaxation term that, at variance with the classical theory of micelle formation, is subject to a broad distribution of relaxation times. Analysis of the shape of this term evidences a coupling between the kinetics of micelle formation/disintegration and noncritical fluctuations in the local concentrations of surfactant monomers, oligomers, and micellar structures. A theoretical model, based on the assumption of a rate process in parallel to the fluctuations, applies well to the broadness of the experimental spectra. An initial increase in the concentration dependence of the principle relaxation time above the cmc is compatible with the high content of oligomers but is more distinctive than predicted by an extended model of micelle formation. The dependence of the relaxation amplitude upon surfactant concentration indicates incomplete dissociation of counterions. An additional high-frequency wing in the spectra is assigned to different structure factors of monomers and micelles. It may, however, also contain contributions from relaxations due to the formation/disintegration kinetics of oligomers and to the structural isomerization of surfactant alkyl chains. © 2011 American Chemical Society.

Buchholz D.,University of Gottingen | Stormer E.,University of OsloOslo
Communications in Mathematical Physics | Year: 2015

The concepts of superposition and of transition probability, familiar from pure states in quantum physics, are extended to locally normal states on funnels of type I∞ factors. Such funnels are used in the description of infinite systems, appearing for example in quantum field theory or in quantum statistical mechanics; their respective constituents are interpreted as algebras of observables localized in an increasing family of nested spacetime regions. Given a generic reference state (expectation functional) on a funnel, e.g. a ground state or a thermal equilibrium state, it is shown that irrespective of the global type of this state all of its excitations, generated by the adjoint action of elements of the funnel, can coherently be superimposed in a meaningful manner. Moreover, these states are the extreme points of their convex hull and as such are analogues of pure states. As further support of this analogy, transition probabilities are defined, complete families of orthogonal states are exhibited and a one-to-one correspondence between the states and families of minimal projections on a Hilbert space is established. The physical interpretation of these quantities relies on a concept of primitive observables. It extends the familiar framework of observable algebras and avoids some counter intuitive features of that setting. Primitive observables admit a consistent statistical interpretation of corresponding measurements and their impact on states is described by a variant of the von Neumann-Lüders projection postulate. © Springer-Verlag Berlin Heidelberg 2015.

Buchholz D.,University of Gottingen | Lechner G.,University of Vienna | Summers S.J.,University of Florida
Communications in Mathematical Physics | Year: 2011

Warped convolutions of operators were recently introduced in the algebraic framework of quantum physics as a new constructive tool. It is shown here that these convolutions provide isometric representations of Rieffel's strict deformations of C*-dynamical systems with automorphic actions of ℝn, whenever the latter are presented in a covariant representation. Moreover, the device can be used for the deformation of relativistic quantum field theories by adjusting the convolutions to the geometry of Minkowski space. The resulting deformed theories still comply with pertinent physical principles and their Tomita-Takesaki modular data coincide with those of the undeformed theory; but they are in general inequivalent to the undeformed theory and exhibit different physical interpretations. © 2010 The Author(s).

Leichsenring F.,Justus Liebig University | Leibing E.,University of Gottingen | Kruse J.,Justus Liebig University | New A.S.,Mount Sinai School of Medicine | Leweke F.,Justus Liebig University
The Lancet | Year: 2011

Recent research findings have contributed to an improved understanding and treatment of borderline personality disorder. This disorder is characterised by severe functional impairments, a high risk of suicide, a negative effect on the course of depressive disorders, extensive use of treatment, and high costs to society. The course of this disorder is less stable than expected for personality disorders. The causes are not yet clear, but genetic factors and adverse life events seem to interact to lead to the disorder. Neurobiological research suggests that abnormalities in the frontolimbic networks are associated with many of the symptoms. Data for the effectiveness of pharmacotherapy vary and evidence is not yet robust. Specific forms of psychotherapy seem to be beneficial for at least some of the problems frequently reported in patients with borderline personality disorder. At present, there is no evidence to suggest that one specific form of psychotherapy is more effective than another. Further research is needed on the diagnosis, neurobiology, and treatment of borderline personality disorder. © 2011 Elsevier Ltd.

Reiner-Drehwald M.E.,University of Gottingen
Cryptogamie, Bryologie | Year: 2011

Based on the study of type material of Neotropical Lejeuneaceae, the following new combination and synonyms are proposed: Ceratolejeunea temnantha (Spruce) comb, nov. (basionym: Lejeunea temnantha), Lejeunea huctumalcensis Lindenb. et Gottsche (= Hygrolejeunea grossereticulata Gottsche ex Steph., = H. sacculata Steph., = H. wrightii Steph.), Lepidolejeunea involuta (Gottsche) Grolle (= Hygrolejeunea glaziovii Steph.), Mastigolejeunea plicatiflora (Spruce) Steph. (= Lejeunea plicata Spruce). Ceratolejeunea temnantha is described and illustrated. © 2011 Adac. Tous droits réservés.

Holobar A.,University of Maribor | Minetto M.A.,University of Turin | Farina D.,University of Gottingen
Journal of Neural Engineering | Year: 2014

Objective. A signal-based metric for assessment of accuracy of motor unit (MU) identification from high-density surface electromyograms (EMG) is introduced. This metric, so-called pulse-to-noise-ratio (PNR), is computationally efficient, does not require any additional experimental costs and can be applied to every MU that is identified by the previously developed convolution kernel compensation technique. Approach. The analytical derivation of the newly introduced metric is provided, along with its extensive experimental validation on both synthetic and experimental surface EMG signals with signal-to-noise ratios ranging from 0 to 20 dB and muscle contraction forces from 5% to 70% of the maximum voluntary contraction. Main results. In all the experimental and simulated signals, the newly introduced metric correlated significantly with both sensitivity and false alarm rate in identification of MU discharges. Practically all the MUs with PNR > 30 dB exhibited sensitivity >90% and false alarm rates <2%. Therefore, a threshold of 30 dB in PNR can be used as a simple method for selecting only reliably decomposed units. Significance. The newly introduced metric is considered a robust and reliable indicator of accuracy of MU identification. The study also shows that high-density surface EMG can be reliably decomposed at contraction forces as high as 70% of the maximum. © 2014 IOP Publishing Ltd.

Gartner J.,University of Gottingen
Biochimica et Biophysica Acta - Molecular Basis of Disease | Year: 2012

Peroxisomal disorders are an important group of neurometabolic diseases. The clinical presentation is varied in terms of age of onset, severity, and different neurological symptoms. The clinical course spans from death in infancy, rapid functional decline, slow decline on long-term followup, to apparent stable course. Leukoencephalopathy and developmental anomalies are characteristic findings on cerebral MR imaging. From a diagnostic point of view the disorders can be clinically subdivided into four broad categories: (1) the Zellweger spectrum disorders and the peroxisomal ß-oxidation disorders, (2) the rhizomelic chondrodysplasia punctata spectrum disorders, (3) the X-linked adrenoleukodystrophy/adrenomyeloneuropathy complex and (4) the remaining disorders. This article discusses the role of MRI findings in the clinical approach of peroxisomal disorders with neurological disease. This article is part of a Special Issue entitled: Metabolic Functions and Biogenesis of peroxisomes in Health and Disease. © 2012 Elsevier B.V..

Witthaut D.,Max Planck Institute for Dynamics and Self-Organization | Timme M.,Max Planck Institute for Dynamics and Self-Organization | Timme M.,University of Gottingen
New Journal of Physics | Year: 2012

Robust synchronization is essential to ensure the stable operation of many complex networked systems such as electric power grids. Increasing energy demands and more strongly distributing power sources raise the question of where to add new connection lines to the already existing grid. Here we study how the addition of individual links impacts the emergence of synchrony in oscillator networks that model power grids on coarse scales. We reveal that adding new links may not only promote but also destroy synchrony and link this counter-intuitive phenomenon to Braess's paradox known for traffic networks. We analytically uncover its underlying mechanism in an elementary grid example, trace its origin to geometric frustration in phase oscillators, and show that it generically occurs across a wide range of systems. As an important consequence, upgrading the grid requires particular care when adding new connections because some may destabilize the synchronization of the grid - and thus induce power outages. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

Metzner W.,Max Planck Institute for Solid State Research | Salmhofer M.,University of Heidelberg | Honerkamp C.,RWTH Aachen | Meden V.,RWTH Aachen | Schonhammer K.,University of Gottingen
Reviews of Modern Physics | Year: 2012

Numerous correlated electron systems exhibit a strongly scale-dependent behavior. Upon lowering the energy scale, collective phenomena, bound states, and new effective degrees of freedom emerge. Typical examples include (i) competing magnetic, charge, and pairing instabilities in two-dimensional electron systems; (ii) the interplay of electronic excitations and order parameter fluctuations near thermal and quantum phase transitions in metals; and (iii) correlation effects such as Luttinger liquid behavior and the Kondo effect showing up in linear and nonequilibrium transport through quantum wires and quantum dots. The functional renormalization group is a flexible and unbiased tool for dealing with such scale-dependent behavior. Its starting point is an exact functional flow equation, which yields the gradual evolution from a microscopic model action to the final effective action as a function of a continuously decreasing energy scale. Expanding in powers of the fields one obtains an exact hierarchy of flow equations for vertex functions. Truncations of this hierarchy have led to powerful new approximation schemes. This review is a comprehensive introduction to the functional renormalization group method for interacting Fermi systems. A self-contained derivation of the exact flow equations is presented and frequently used truncation schemes are described. Reviewing selected applications it is shown how approximations based on the functional renormalization group can be fruitfully used to improve our understanding of correlated fermion systems. © 2012 American Physical Society.

Solveen C.,University of Gottingen
Classical and Quantum Gravity | Year: 2012

On the example of a free massless and conformally coupled scalar field, it is argued that in quantum field theory in curved spacetimes with the time-like Killing field, the corresponding KMS states (generalized Gibbs ensembles) at parameter β > 0 need not possess a definite temperature in the sense of the zeroth law. In fact, these states, although passive in the sense of the second law, are not always in local thermal equilibrium (LTE). A criterion characterizing LTE states with sharp local temperature is discussed. Moreover, a proposal is made for fixing the renormalization freedom of composite fields which serve as 'thermal observables' and a new definition of the thermal energy of LTE states is introduced. Based on these results, a general relation between the local temperature and the parameter β is established for KMS states in (anti) de Sitter spacetime. © 2012 IOP Publishing Ltd.

Goenner H.,University of Gottingen
General Relativity and Gravitation | Year: 2012

Between 1941 and 1962, scalar-tensor theories of gravitation were suggested four times by different scientists in four different countries. The earliest originator, the Swiss mathematician W. Scherrer, was virtually unknown until now whereas the chronologically latest pair gave their names to a multitude of publications on Brans-Dicke theory. P. Jordan, one of the pioneers of quantum mechanics and quantum field theory, and Y. Thiry, known by his book on celestial mechanics, a student of the mathematician Lichnerowicz, complete the quartet. Diverse motivations for and conceptual interpretations of their theories will be discussed as well as relations among them. Also, external factors like language, citation habits, or closeness to the mainstream are considered. It will become clear why Brans-Dicke theory, although structurally a déjà-vu, superseded all the other approaches. © 2012 The Author(s).

Melatonin is a pleiotropically acting regulator molecule, which influences numerous physiological functions. Its secretion by the pineal gland progressively declines by age. Strong reductions of circulating melatonin are also observed in numerous disorders and diseases, including Alzheimer's disease, various other neurological and stressful conditions, pain, cardiovascular diseases, cases of cancer, endocrine and metabolic disorders, in particular diabetes type 2. The significance of melatonergic signaling is also evident from melatonin receptor polymorphisms associated with several of these pathologies. The article outlines the mutual relationship between circadian oscillators and melatonin secretion, the possibilities for readjustment of rhythms by melatonin and its synthetic analogs, the consequences for circadian rhythm-dependent disorders concerning sleep and mood, and limits of treatment. The necessity of distinguishing between short-acting melatonergic effects, which are successful in sleep initiation and phase adjustments, and attempts of replacement strategies is emphasized. Properties of approved and some investigational melatonergic agonists are compared.

Weber S.,University of Gottingen | Saftig P.,University of Kiel
Development (Cambridge) | Year: 2012

Proteolytic enzymes belonging to the A Disintegin And Metalloproteinase (ADAM) family are able to cleave transmembrane proteins close to the cell surface, in a process referred to as ectodomain shedding. Substrates for ADAMs include growth factors, cytokines, chemokines and adhesion molecules, and, as such, many ADAM proteins play crucial roles in cell-cell adhesion, extracellular and intracellular signaling, cell differentiation and cell proliferation. In this Review, we summarize the fascinating roles of ADAMs in embryonic and adult tissue development in both vertebrates and invertebrates. © 2012. Published by The Company of Biologists Ltd.

Hohnwald S.,University of Gottingen
Agriculture, Ecosystems and Environment | Year: 2016

In northeastern Pará, smallholder agriculture systems are still based on secondary forest fallows, nationally called "capoeira", presumed to contain a remarkable amount of underutilized valuable woody species, for instance as supplementary forage for cattle. We tested five promising capoeira species, namely Phenakospermum guyannense, Cecropia palmata, Attalea maripa, Inga edulis, and Abarema jupunba by comparing its relative palatability-i.e., the palatability differences between the tested species and the reference forage legumes, forage grass, and between the other tested species-, heights, biomass production, and main nutritive values with the well-known tropical forage legumes Cratylia argentea and Flemingia macrophylla. Additionally, the locally common domesticated species Tithonia diversifolia, Mangifera indica, and Racosperma mangium were also included in the trial, all implemented in a randomized block design on a Brachiaria-pasture (n = 2000 saplings, 8 replication blocks). After two years of establishment, four steers with an average body mass of 506 kg browsed the trial (2 AU/ha). The relative palatability testing showed that A. jupunba, M. indica and also surprisingly R. mangium (all >20% of its respective total biomass) matched the consumed biomass of F. macrophylla, while C. palmata (>60%) even surpassed very palatable C. argentea. R. mangium also had the highest biomass production, while the other species showed just regular growth and establishing rates. Protein contents of all species were above 6%, most of them higher than 10% and in the case of T. diversifolia even above 20%. Thus, all tested species almost reached the quality of the reference legumes. However, as plant secondary compounds were not regarded in this trial, recommendations as supplementary forage plants can only be given with reservations. The results suggest that smallholders possess cheap forage supplement alternatives on their farms and even on their pasture plots, which simply have to be tolerated by just pruning them into accessible heights for animals. However, sapling transplantation from shady capoeiras on old slightly degraded pastures for biomass enrichment cannot be recommended. © 2015 Elsevier B.V..

Hardeland R.,University of Gottingen | Madrid J.A.,University of Murcia | Tan D.-X.,University of Texas Health Science Center at San Antonio | Reiter R.J.,University of Texas Health Science Center at San Antonio
Journal of Pineal Research | Year: 2012

Evidence is accumulating regarding the importance of circadian core oscillators, several associated factors, and melatonin signaling in the maintenance of health. Dysfunction of endogenous clocks, melatonin receptor polymorphisms, age-and disease-associated declines of melatonin likely contribute to numerous diseases including cancer, metabolic syndrome, diabetes type 2, hypertension, and several mood and cognitive disorders. Consequences of gene silencing, overexpression, gene polymorphisms, and deviant expression levels in diseases are summarized. The circadian system is a complex network of central and peripheral oscillators, some of them being relatively independent of the pacemaker, the suprachiasmatic nucleus. Actions of melatonin on peripheral oscillators are poorly understood. Various lines of evidence indicate that these clocks are also influenced or phase-reset by melatonin. This includes phase differences of core oscillator gene expression under impaired melatonin signaling, effects of melatonin and melatonin receptor knockouts on oscillator mRNAs or proteins. Cross-connections between melatonin signaling pathways and oscillator proteins, including associated factors, are discussed in this review. The high complexity of the multioscillator system comprises alternate or parallel oscillators based on orthologs and paralogs of the core components and a high number of associated factors with varying tissue-specific importance, which offers numerous possibilities for interactions with melatonin. It is an aim of this review to stimulate research on melatonin signaling in peripheral tissues. This should not be restricted to primary signal molecules but rather include various secondarily connected pathways and discriminate between direct effects of the pineal indoleamine at the target organ and others mediated by modulation of oscillators. © 2011 John Wiley & Sons A/S.

Giessen L.,University of Gottingen | Giessen L.,Wageningen University
International Forestry Review | Year: 2013

The objectives of this review article are, firstly, to provide an overview of the literature on the main characteristics of what is referred to as the international forest regime and secondly, based on this, to review explanations for fragmentation as its core characteristic. A third aim of the article is to propose fields for future policy-oriented research on global forest governance, the international forest regime and its fragmentation. The article discusses different strands of literature and academic views on the existence and main characteristics of an international forest regime. It regards the recent notion of an international forest regime complex to be a fruitful topic for future research proposals and finds that fragmentation is its analytical core characteristic. In addition, the article reviews partial explanations for the great relevance of fragmentation in the case of the forest regime complex. It discriminates between domestic factors and causes as opposed to those resulting from the international system. Based on the review, the article suggests, lastly, fields for future research on global forest governance, the international forest regime complex and its fragmentation.

D'Yakonov V.A.,Russian Academy of Sciences | Trapeznikova O.A.,Russian Academy of Sciences | De Meijere A.,University of Gottingen | Dzhemilev U.M.,Russian Academy of Sciences
Chemical Reviews | Year: 2014

Synthetic and natural spirocarbocycles attract the attention of organic chemists due to their unique structural features and numerous possible reactions in which they undergo carbon-carbon bond cleavage. The peculiar properties of certain targeted spirocarbocycles such as high reactivities of some or fairly high thermal stabilities of others have challenged many organic chemists to develop the appropriate preparative approaches to specific compounds. There are quite a few published reviews, papers, and patents, some of which are outdated, that mainly present methods for the synthesis based on multistep synthetic strategies and exotic and/or expensive reagents. Ethoxycarbonyltriangulanes have been widely used in the preparations of higher members in the triangulane family. The intramolecular analogue of the cyclopropanation of aromatic compounds known as the Buchner reaction can also be counted as a method for the preparation of spiro compounds.

Muller J.L.,University of Gottingen
Behavioral sciences & the law | Year: 2010

"Psychopathy" is a construct that has come into vogue again in science and practice. In line with the growing impact, different diagnostic approaches have been used to investigate forensically relevant social behavior as well as involved brain functions and structures. Research on psychopathy has become of major importance for empirical research in forensic psychiatry. An overview on the development of the concept of psychopathy is given; the heterogeneity of the diagnostic tools is addressed, focusing critically on the characteristics of the included samples. Neurobiological findings on psychopathy are presented, focusing in particular on structural and functional imaging data. Limitations and further requirements of neuroimaging research in psychopathy are discussed. In order to emphasize the limitations of lesion studies, in particular in a forensic context, a case report on pseudoneurasthenia following orbitofrontal brain damage without any change in behavior is presented.

Ofir A.,University of Gottingen
Astronomy and Astrophysics | Year: 2014

Context. Transit surveys, both ground-and space-based, have already accumulated a large number of light curves that span several years. Aims. The search for transiting planets in these long time series is computationally intensive. We wish to optimize the search for both detection and computational efficiencies. Methods. We assume that the searched systems can be described well by Keplerian orbits. We then propagate the effec ts of different system parameters to the detection parameters. Results. We show that the frequency information content of the light curve is primarily determined by the duty cycle of the transit signal, and thus the optimal frequency sampling is found to be cubic and not linear. Further optimization is achieved by considering duty-cycle dependent binning of the phased light curve. By using the (standard) BLS, one is either fairly insensitive to long-period planets or less sensitive to short-period planets and computationally slower by a significant factor of ∼330 (for a 3 yr long dataset). We also show how the physical system parameters, such as the host star's size and mass, directly affect transit detection. This understanding can then be used to optimize the search for every star individually. Conclusions. By considering Keplerian dynamics explicitly rather than implicitly one can optimally search the BLS parameter space. The presented Optimal BLS enhances the detectability of both very short and very long period planets, while allowing such searches to be done with much reduced resources and time. The Matlab/Octave source code for Optimal BLS is made available. © ESO, 2014.

Moser T.,University of Gottingen | Starr A.,University of California at Irvine
Nature Reviews Neurology | Year: 2016

Sensorineural hearing impairment is the most common form of hearing loss, and encompasses pathologies of the cochlea and the auditory nerve. Hearing impairment caused by abnormal neural encoding of sound stimuli despite preservation of sensory transduction and amplification by outer hair cells is known as 'auditory neuropathy'. This term was originally coined for a specific type of hearing impairment affecting speech comprehension beyond changes in audibility: patients with this condition report that they "can hear but cannot understand". This type of hearing impairment can be caused by damage to the sensory inner hair cells (IHCs), IHC ribbon synapses or spiral ganglion neurons. Human genetic and physiological studies, as well as research on animal models, have recently shown that disrupted IHC ribbon synapse function-resulting from genetic alterations that affect presynaptic glutamate loading of synaptic vesicles, Ca 2+ influx, or synaptic vesicle exocytosis-leads to hearing impairment termed 'auditory synaptopathy'. Moreover, animal studies have demonstrated that sound overexposure causes excitotoxic loss of IHC ribbon synapses. This mechanism probably contributes to hearing disorders caused by noise exposure or age-related hearing loss. This Review provides an update on recently elucidated sensory, synaptic and neural mechanisms of hearing impairment, their corresponding clinical findings, and discusses current rehabilitation strategies as well as future therapies. © 2016 Macmillan Publishers Limited.

Noubactep C.,University of Gottingen | Noubactep C.,Kultur und Nachhaltige Entwicklung CDD e.V.
Clean - Soil, Air, Water | Year: 2013

Metallic iron (Fe0) is often reported as a reducing agent for environmental remediation. There is still controversy as to whether Fe0 plays any significant direct role in the process of contaminant reductive transformation. The view that Fe0 is mostly a generator of reducing agents (e.g. H, H2 and FeII) and Fe oxyhydroxides has been either severely refuted or just tolerated. The tolerance is based on the simplification that, without Fe0, no secondary reducing agents could be available. Accordingly, Fe0 serves as the original source of electron donors (including H, H2 and FeII). The objective of this communication is to refute the named simplification and establish that quantitative reduction results from secondary reducing agents. For this purpose, reports on aqueous contaminant removal by Al0, Fe0 and Zn0 are comparatively discussed. Results indicated that reduction may be quantitative in aqueous systems containing Fe0 and Zn0 while no significant reduction is observed in Al0/H2O systems. Given that Al0 is a stronger reducing agent than Fe0 and Zn0, it is concluded that contaminant reduction in Fe0/H2O systems results from synergic interactions between H/H2 and FeII within porous Fe oxyhydroxides. This conclusion corroborates the operating mode of Fe0 bimetallics as H/H2 producing systems for indirect contaminant reduction. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Junker A.,University of Gottingen
FEBS Letters | Year: 2011

MicroRNAs (miRNAs) comprise a group of several hundred, small non-coding RNA molecules with a fundamental influence on the regulation of gene expression. Certain miRNAs are altered in blood cells of multiple sclerosis (MS), and active and inactive MS brain lesions have distinct miRNA expression profiles. Several miRNAs such as miR-155 or miR-326 are considerably overexpressed in active MS lesions versus controls, and mice lacking these miRNAs either through knock-out (miR-155) or by in vivo silencing (miR-326) show a reduction of symptoms in experimental autoimmune encephalomyelitis (EAE), a model system for multiple sclerosis. This review describes miRNAs regulated in the blood or in brain lesions of MS patients in the context of their previously described functions in physiology and pathophysiology. © 2011 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Miao G.-X.,Massachusetts Institute of Technology | Munzenberg M.,University of Gottingen | Moodera J.S.,Massachusetts Institute of Technology
Reports on Progress in Physics | Year: 2011

The phenomenon of quantum tunneling, which was discovered almost a century ago, has led to many subsequent discoveries. One such discovery, spin polarized tunneling, was made 40 years ago by Robert Meservey and Paul Tedrow (Tedrow and Meservey 1971 Phys. Rev. Lett. 26 192), and it has resulted in many fundamental observations and opened up an entirely new field of study. Until the mid-1990s, this field developed at a steady, low rate, after which a huge increase in activity suddenly occurred as a result of the unraveling of successful spin tunneling between two ferromagnets. In the past 15 years, several thousands of papers related to spin polarized tunneling and transport have been published, making this topic one of the hottest areas in condensed matter physics from both fundamental science and applications viewpoints. Many review papers and book chapters have been written in the past decade on this subject. This paper is not exhaustive by any means; rather, the emphases are on recent progress, technological developments and informing the reader about the current direction in which this topic is moving. © 2011 IOP Publishing Ltd.

Enders D.,RWTH Aachen | Seppelt M.,RWTH Aachen | Beck T.,University of Gottingen
Advanced Synthesis and Catalysis | Year: 2010

The enantioselective organocatalytic synthesis of arylglycines has been developed employing 1 mol% of an enantiopure N-triflyl phosphoramide Brønsted acid as organocatalyst. Various differently substituted phenylglycine derivatives can be synthesized in good to excellent yields and enantiomeric excesses based on a Friedel-Crafts alkylation of electron-rich arenes with a glyoxylate imine. A novel protocol for the deprotection of the N-tert-butylsulfonyl (Bus) group has also been developed. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Noubactep C.,University of Gottingen
Chemical Engineering Journal | Year: 2010

Characterizing the intrinsic reactivity of iron materials for environmental remediation has received relative little interest. Available results are mostly based on the removal extent of selected contaminants in batch systems. Under static conditions however, contaminant removal depends on the properties of the oxide-film. The present study was performed to investigate the chemical reactivity of nine Fe0 materials under conditions that minimize the formation of an oxide-film on the metal surface. Ethylenediaminetetraacetate (EDTA) was used to sustain Fe0 dissolution during column testing for 2 months. The results confirm Fe0 dissolution rate in 2mM EDTA as a good tool for comparative reactivity characterization. Moreover, long-term column studies with 2mM EDTA enable: (i) the evidence of increased powdered Fe0 reactivity relative to granular materials and (ii) a clear differentiation among granular materials which exhibited very closed extents of iron dissolution under static conditions. Future works comparing Fe0 intrinsic reactivity should ideally characterize material behaviour in an oxide-free system and compare the results to those obtained under relevant experimental conditions. © 2010 Elsevier B.V.

Noubactep C.,University of Gottingen | Noubactep C.,Kultur und Nachhaltige Entwicklung CDD e.V.
Chemical Engineering Journal | Year: 2010

A new concept for household and large-scale safe drinking water production is presented. Raw water is successively filtered through a series of sand and iron filters. Sand filters mostly remove suspended particles (media filtration) and iron filters remove anions, cations, micro-pollutants, natural organic matter, and micro-organisms including pathogens (reactive filtration). Accordingly, treatment steps conventionally achieved with flocculation, sedimentation, rapid sand filtration, activated carbon filtration, and disinfection are achieved in the new concept in only two steps. To prevent bed clogging, Fe0 is mixed with inert materials, yielding Fe0/sand filters. Efficient water treatment in Fe0/sand filters has been extensively investigated during the past two decades. Two different contexts are particularly important in this regard: (i) underground permeable reactive barriers and (ii) household water filters. In these studies, the process of aqueous iron corrosion in a packed bed was proven very efficient for unspecific aqueous contaminant removal. Been based on a chemical process (iron corrosion), efficient water treatment in Fe0 beds is necessarily coupled with a slow flow rate. Therefore, for large communities several filters should work in parallel to produce enough water for storage and distribution. It appears that water filtration through Fe0/sand filters is an efficient, affordable, a flexible technology for the whole world. © 2010 Elsevier B.V.

Berndt M.,Max Planck Institute of Molecular Cell Biology and Genetics | Lorenz M.,Max Planck Institute of Molecular Cell Biology and Genetics | Enderlein J.,University of Gottingen | Diez S.,Max Planck Institute of Molecular Cell Biology and Genetics
Nano Letters | Year: 2010

We present a novel fluorescence lifetime imaging microscopy technique to measure absolute positions of fluorescent molecules within 100 nm above a metalized surface based on distance-dependent fluorescence lifetime modulations. We apply this technique to fluorescently labeled microtubules as optical probes with various unlabeled proteins attached. By measuring the fluorescence lifetimes, we obtain the position of the microtubules and therefore determine the geometrical size of the attached proteins with nanometer precision. © 2010 American Chemical Society.

Desai M.S.,Max Planck Institute for Terrestrial Microbiology | Desai M.S.,University of Gottingen | Brune A.,Max Planck Institute for Terrestrial Microbiology
ISME Journal | Year: 2012

Although it is well documented that the lack of nitrogen in the diet of wood-feeding termites is compensated by the nitrogen-fixing capacity of their gut microbiota, the bacteria responsible for this activity are largely unknown. Here, we analyzed the diversity and expression of nitrogenase genes (homologs of nifH) in four species of dry-wood termites (Kalotermitidae), which thrive on a particularly nitrogen-poor resource. Although each species harbored a highly diverse suite of termite-specific homologs in their microliter-sized hindgut, only a core set related to nifH genes of Treponema and Azoarcus spp., Azobacteroides pseudotrichonymphae, the first member of the Bacteroidales identified as a diazotroph, and termite-gut-specific anfH genes of hitherto unknown origin were preferentially expressed. Transcription patterns corroborated that the populations of active diazotrophs differ fundamentally between termite genera. Capillary-picked suspensions of the flagellates Devescovina arta and Snyderella tabogae revealed that their bacterial ectosymbionts each possess two paralogs of nifH, which apparently have been acquired consecutively during evolution of Bacteroidales, but only one of them (anfH) is actively expressed. Transcription patterns correlated neither with the molybdenum content of the diet nor with intestinal hydrogen concentrations, measured with microsensors. We propose that the nitrogen-fixing community in different dry-wood termites is shaped by the symbionts of their specific flagellate populations. Our findings suggest that the diazotrophic nature of Armantifilum devescovinae has an important role in the nitrogen metabolism of dry-wood termites and is the driving force of co-evolution with its flagellate host. © 2012 International Society for Microbial Ecology All rights reserved.

Neacsu C.C.,University of Washington | Berweger S.,University of Washington | Olmon R.L.,University of Washington | Saraf L.V.,Pacific Northwest National Laboratory | And 2 more authors.
Nano Letters | Year: 2010

Focusing light to subwavelength dimensions has been a long-standing desire in optics but has remained challenging, even with new strategies based on near-field effects, polaritons, and metamaterials. The adiabatic propagation of surface plasmon polaritons (SPP) on a conical taper as proposed theoretically has recently emerged as particularly promising to obtain a nanoconfined light source at the tip. Employing grating-coupling of SPPs onto gold tips, we demonstrate plasmonic nanofocuslng into a localized excitation of ∼20 nm in size and investigate its near- and far-field behavior. Por cone angles of ∼10-20°, the breakdown of the adiabatic propagation conditions is found to be localized at or near the apex region with ∼10 nm radius. Despite an asymmetric side-on SPP excitation, the apex far-field emission with axial polarization characteristics representing a radially symmetric SPP mode in the nanofocus confirms that the conical tip acts as an effective mode filter with only the fundamental radially symmetric TM mode (m = 0) propagating to the apex. We demonstrate the use of these tips as a source for nearly background-free scattering-type scanning near-field optical microscopy (s-SNOM). © 2010 American Chemical Society.

Thiele J.C.,University of Gottingen | Grimm V.,Helmholtz Center for Environmental Research
Environmental Modelling and Software | Year: 2010

NetLogo is a software platform for agent-based modelling that is increasingly used in ecological and environmental modelling. So far, for comprehensive analyses of agent-based models (ABMs) implemented in NetLogo, results needed to be written to files and evaluated by using external software, for example R. Ideally, however, it would be possible to call any R function from within a NetLogo program. This would allow sophisticated interactive statistical analysis of model structure and dynamics, using R functions and packages for generating certain statistical distributions and experimental design, and for implementing complex descriptive submodels within ABMs. Here we present an R extension of NetLogo. It consists of only nine new NetLogo primitives for sending data between NetLogo and R and for calling R functions (six additional primitives for debugging). We demonstrate the usage of the R extension with three short examples. © 2010 Elsevier Ltd. All rights reserved.

This review focuses on gene transcription patterns of leukemogenic S-phases in mitotic cell cycles for identification of enzymatic reactions as potential targets for epigenetics-based drug therapy. Transcription of leukemic genes is triggered by reprogrammed transcription factors (TFs) mediated by chromatin histones. Reprogrammed TFs originate from transcriptional alterations of CpG methylation patterns of mutated epigenetic genes. They preserve memory information of earlier leukemogenic exposures, even transgenerationally via the zygote, through small (e.g. pi)RNA transmitted between cells by exosomes. Normally, reprogrammed TFs are enzymatically silenced and stored as markers in heterochromatic domains. Failure of intra S-phase surveillance (IS) permits the formation and continual operation of DNA replication forks in spite of persisting genotoxic stress. Silenced TFs are re-activated by euchromatin, most likely through leakages of insulator barriers of cis-regulating chromatin modulators (CRM) that normally separate hetero- from euchromatin domains. During transport by sliding nucleosomes, reprogrammed leukemogenic TFs are misplaced at transcription factor binding-/starting-sites (TFBS /TSS) allowing them to interact with and trigger replication of mutated leukemic genes. Interactions of enzymatically reprogrammed TFs, transcribed from mutated epigenetic genes, with replicating leukemic genes at TFBS/TSSs are key driving forces in leukemogenesis. Probably, epigenetic genes, although mutated, still retain their control of replication of leukemic genes. Epigenetics-based enzyme inhibitors must target reprogrammed TFs. Prudently, therapeutic corrections should be introduced within the frame of conventional, cytoreductive treatment protocols. Alternatively, reprogrammed TFs could be replaced by cell populations with regular TF production. Clinically, classification of leukemias should be based on their epigenetic presentation.

Xu H.,Max Planck Institute for Dynamics and Self-Organization | Pumir A.,Ecole Normale Superieure de Lyon | Bodenschatz E.,Max Planck Institute for Dynamics and Self-Organization | Bodenschatz E.,University of Gottingen | Bodenschatz E.,Cornell University
Nature Physics | Year: 2011

The disorganized fluctuations of turbulence are crucial in the transport of particles or chemicals and could play a decisive role in the formation of rain in clouds, the accretion process in protoplanetary disks, and how animals find their mates or prey. These and other examples suggest a yet-to-be-determined unifying structure of turbulent flows. Here, we unveil an important ingredient of turbulence by taking the perspective of an observer who perceives its world with respect to three distant neighbours all swept by the flow. The time evolution of the observer's world can be decomposed into rotation and stretching. We show that, in this Lagrangian frame, the axis of rotation aligns with the initially strongest stretching direction, and that the dynamics can be understood by the conservation of angular momentum. This pirouette effect' thus appears as an important structural component of turbulence, and elucidates the mechanism for small-scale generation in turbulence. © 2011 Macmillan Publishers Limited. All rights reserved.

Eckstein A.,University of Duisburg - Essen | Schittkowski M.,University of Gottingen | Esser J.,University of Duisburg - Essen
Best Practice and Research: Clinical Endocrinology and Metabolism | Year: 2012

The aims of surgical treatment in Graves's orbitopathy (GO) are improvement of function and appearance. Since antiinflammatory treatment of GO rarely results in a complete resolution of symptoms, surgical treatment is very important for patients well being. Rehabilitative surgery includes orbital decompression, squint correction, lid lengthening and blepharoplasty and these procedures have to be performed in centres of expertise. Various techniques have been developed for orbital decompression which allow now a graded approach to proptosis reduction and optic nerve decompression in emergency situations. Extraocular muscle recessions can be successfully performed to treat most of the patients with diplopia. Only large or complex squint angles are difficult to treat and step by step procedures are recommended in these patients. Lid lengthening procedures are performed most often in GO patients and should be performed under local anaesthesia to get a good result. Serious complications are rare. © 2011 Elsevier Ltd. All rights reserved.

Noubactep C.,University of Gottingen | Schoner A.,Martin Luther University of Halle Wittenberg
Journal of Hazardous Materials | Year: 2010

The interpretation of processes yielding aqueous contaminant removal in the presence of elemental iron (e.g. in Fe0/H2O systems) is subject to numerous complications. Reductive transformations by Fe0 and its primary corrosion products (FeII and H/H2) as well as adsorption onto and co-precipitation with secondary and tertiary iron corrosion products (iron hydroxides, oxyhydroxides, and mixed valence FeII/FeIII green rusts) are considered the main removal mechanisms on a case-to-case basis. Recent progress involving adsorption and co-precipitation as fundamental contaminant removal mechanisms have faced a certain scepticism. This work shows that results from electrocoagulation (EC), using iron as sacrificial electrode, support the adsorption/co-precipitation concept. It is reiterated that despite a century of commercial use of EC, the scientific understanding of the complex chemical and physical processes involved is still incomplete. © 2009 Elsevier B.V. All rights reserved.

Johnsen S.A.,University of Hamburg | Johnsen S.A.,University of Gottingen
FEBS Letters | Year: 2012

The post-translational modification of histone proteins plays an important role in controlling cell fate by directing essentially all DNA-associated nuclear processes. Misregulation and mutation of histone modifying enzymes is a hallmark of tumorigenesis. However, how these different epigenetic modifications lead to tumor initiation and/or progression remains poorly understood. Recent studies have uncovered a potential tumor suppressor role for histone H2B monoubiquitination (H2Bub1). Like many other histone modifications, H2Bub1 has diverse functions and plays roles both in transcriptional activation and repression as well as in controlling mRNA processing and directing DNA repair processes. Notably, H2Bub1 has been linked to transcriptional elongation and is preferentially found in the transcribed region of active genes. Its activity is intimately connected to active transcription and the transcriptional elongation regulatory protein cyclin-dependent kinase-9 (CDK9) and the facilitates chromatin transcription (FACT) complex. This review provides an overview of the current understanding of H2Bub1 function in mammalian systems with a particular emphasis on its role in cancer and potential options for exploiting this knowledge for the treatment of cancer. © 2012 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Rodel C.,Goethe University Frankfurt | Hofheinz R.,University of Heidelberg | Liersch T.,University of Gottingen
Current Opinion in Oncology | Year: 2012

Purpose of review: To discuss the recent developments of multimodal treatment for patients with local advanced rectal cancer, including incorporation of new chemotherapeutic and targeted agents, and the optimal sequence and timing of treatment components. Recent findings: Five randomized trials have been completed to determine whether the addition of oxaliplatin to preoperative, fluorouracil-based chemoradiotherapy (CRT) offers an advantage compared to single-agent fluorouracil CRT. Early results from the ACCORD 12, STAR-01, and NSAPB R-04 trials did not confirm a significant improvement of early efficacy endpoints with the addition of oxaliplatin, whereas the German CAO/ARO/AIO-04 did. Most of the phase II trials incorporating cetuximab into CRT reported disappointingly low rates of pathologic complete response (pCR); the combination of CRT with VEGF inhibition showed encouraging pCR rates; however, it was associated with increased surgical complications. Novel clinical trials address the role of induction chemotherapy, of delayed, minimal or omitted surgery following CRT, or the omission of radiotherapy for selected patients. Summary: At this time, the use of oxaliplatin or targeted agents as component of multimodality treatment for rectal cancer outside of a clinical trial is not recommended. The inclusion of different treatment options, according to tumor stage, location, imaging features, and response, will render the multimodal treatment approach of rectal cancer more risk-adapted. © 2012 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Ackermann L.,University of Gottingen
Pure and Applied Chemistry | Year: 2010

Palladium catalysts allowed for intermolecular direct arylations of heteroarenes with aryl chlorides, tosylates, or mesylates as electrophiles. As an economically attractive alter native, inexpensive copper catalysts could be employed for regioselective C-H bond aryl ations of 1,2,3-triazoles. On the contrary, intermolecular C-H bond functionalizations of arenes were accomplished with ruthenium complexes derived from air-stable (heteroatomsubstituted) secondary phosphine oxide (HASPO) preligands. Particularly, the use of ruthenium( II) carboxylate complexes enabled broadly applicable direct arylations with inter alia aryl tosylates and phenols, and set the stage for unprecedented intermolecular direct alkylations with unactivated alkyl halides bearing β-hydrogens. © 2010 IUPAC.

Clever G.H.,University of Gottingen | Kawamura W.,University of Tokyo | Tashiro S.,University of Tokyo | Shiro M.,Rigaku Corporation | Shionoya M.,University of Tokyo
Angewandte Chemie - International Edition | Year: 2012

Neatly wrapped up: Alternately stacked square-planar platinum(II) complexes inside a dinuclear coordination cage were prepared to give a discrete and soluble Pt 5-array of the Magnus' salt type. Characterization of the complex in solution was complemented by an X-ray crystal structure of {[Pt(pyridine) 4]· [PtCl 4] 2@Cage}; this structure showed the linear, pentanuclear array within the cages and their circular packing into a hollow tubular superstructure. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Transcriptional networks of higher eukaryotes are difficult to obtain. Available experimental data from conventional approaches are sporadic, while those generated with modern high-throughput technologies are biased. Computational predictions are generally perceived as being flooded with high rates of false positives. New concepts about the structure of regulatory regions and the function of master regulator sites may provide a way out of this dilemma. We combined promoter scanning with positional weight matrices with a 4-genome conservativity analysis to predict high-affinity, highly conserved transcription factor (TF) binding sites and to infer TF-target gene relations. They were expanded to paralogous TFs and filtered for tissue-specific expression patterns to obtain a reference transcriptional network (RTN) as well as tissue-specific transcriptional networks (TTNs). When validated with experimental data sets, the predictions done showed the expected trends of true positive and true negative predictions, resulting in satisfying sensitivity and specificity characteristics. This also proved that confining the network reconstruction to the 1% top-ranking TF-target predictions gives rise to networks with expected degree distributions. Their expansion to paralogous TFs enriches them by tissue-specific regulators, providing a reasonable basis to reconstruct tissue-specific transcriptional networks. The concept of master regulator or seed sites provides a reasonable starting point to select predicted TF-target relations, which, together with a paralogous expansion, allow for reconstruction of tissue-specific transcriptional networks.

Flugel A.,University of Gottingen
Seminars in Immunopathology | Year: 2010

Since the first applications of two-photon microscopy in immunology 10 years ago, the number of studies using this advanced technology has increased dramatically. The two-photon microscope allows long-term visualization of cell motility in the living tissue with minimal phototoxicity. Using this technique, we examined brain autoantigen-specific T cell behavior in experimental autoimmune encephalitomyelitis, the animal model of human multiple sclerosis. Even before disease symptoms appear, the autoreactive T cells arrive at their target organ. There they crawl along the intraluminal surface of central nervous system (CNS) blood vessels before they extravasate. In the perivascular environment, the T cells meet phagocytes that present autoantigens. This contact activates the T cells to penetrate deep into the CNS parenchyma, where the infiltrated T cells again can find antigen, be further activated, and produce cytokines, resulting in massive immune cell recruitment and clinical disease. © 2010 The Author(s).

Noubactep C.,University of Gottingen
Environmental Progress and Sustainable Energy | Year: 2010

Aqueous contaminant removal in the presence of metallic iron is often regarded as a reductive transformation mediated by the Fe0 surface. However, successful removal of theoretically nonreducible contaminants has been largely reported. This article presents a rebuttal of the concept of contaminant reductive transformation. It is argued through a careful examination of the evolution of the volume and adsorptive properties of iron and its corrosion products that contaminants are primarily adsorbed and coprecipitated with iron corrosion products. One may wonder how the Fe0 technology will develop with the new concept. © 2009 American Institute of Chemical Engineers.

Farina D.,University of Gottingen | Holobar A.,University of Maribor
Proceedings of the IEEE | Year: 2016

Motor units are the smallest functional units of our movements. The study of their activation provides a window into the mechanisms of neural control of movement in humans. The classic methods for motor unit investigations date to several decades ago. They are based on invasive recordings with selective needle or wire electrodes. Conversely, the noninvasive (surface) EMG has been commonly processed as an interference signal, with the extraction of its global characteristics, e.g., amplitude. These characteristics, however, are only crudely associated to the underlying motor unit activities. In the last decade, methods have been proposed for reliably extracting individual motor unit activities from the interference surface EMG signal. We describe these methods in this review, with a focus on blind source separation (BSS) and techniques used on decomposed EMG signals. For example, from the motor unit discharge timings, information can be extracted regarding the synaptic input received by the corresponding motor neurons. In reviewing these methods, we also provide examples of applications in representative conditions, such as pathological tremor. In conclusion, we provide an overview of processing methods of the surface EMG signal that allow a reliable characterization of individual motor units in vivo in humans. © 1963-2012 IEEE.

BRCA1 is a tumor-suppressor gene associated with, but not restricted to, breast and ovarian cancer and implicated in various biological functions. During mitosis, BRCA1 and its positive regulator Chk2 are localized at centrosomes and are required for the regulation of microtubule plus end assembly, thereby ensuring faithful mitosis and numerical chromosome stability. However, the function of BRCA1 during mitosis has not been defined mechanistically. To gain insights into the mitotic role of BRCA1 in regulating microtubule assembly, we systematically identified proteins interacting with BRCA1 during mitosis and found the centrosomal protein Cep72 as a novel BRCA1-interacting protein. CEP72 is frequently upregulated in colorectal cancer tissues and overexpression of CEP72 mirrors the consequences of BRCA1 loss during mitosis. In detail, the overexpression of CEP72 causes an increase in microtubule plus end assembly, abnormal mitotic spindle formation and the induction of chromosomal instability. Moreover, we show that high levels of Cep72 counteract Chk2 as a positive regulator of BRCA1 to ensure proper mitotic microtubule assembly. Thus, CEP72 represents a putative oncogene in colorectal cancer that might negatively regulate the mitotic function of BRCA1 to ensure chromosomal stability.Oncogene advance online publication, 24 August 2015; doi:10.1038/onc.2015.290. © 2015 Macmillan Publishers Limited

Alexa M.,TU Berlin | Wardetzky M.,University of Gottingen
ACM Transactions on Graphics | Year: 2011

While the theory and applications of discrete Laplacians on triangulated surfaces are well developed, far less is known about the general polygonal case. We present here a principled approach for constructing geometric discrete Laplacians on surfaces with arbitrary polygonal faces, encompassing non-planar and non-convex polygons. Our construction is guided by closely mimicking structural properties of the smooth Laplace-Beltrami operator. Among other features, our construction leads to an extension of the widely employed cotan formula from triangles to polygons. Besides carefully laying out theoretical aspects, we demonstrate the versatility of our approach for a variety of geometry processing applications, embarking on situations that would have been more difficult to achieve based on geometric Laplacians for simplicial meshes or purely combinatorial Laplacians for general meshes. © 2011 ACM.

Mani N.,University of Gottingen | Huettig F.,Max Planck Institute for Psycholinguistics | Huettig F.,Radboud University Nijmegen
Journal of Experimental Child Psychology | Year: 2014

Despite the efficiency with which language users typically process spoken language, a growing body of research finds substantial individual differences in both the speed and accuracy of spoken language processing potentially attributable to participants' literacy skills. Against this background, the current study took a look at the role of word reading skill in listeners' anticipation of upcoming spoken language input in children at the cusp of learning to read; if reading skills affect predictive language processing, then children at this stage of literacy acquisition should be most susceptible to the effects of reading skills on spoken language processing. We tested 8-year-olds on their prediction of upcoming spoken language input in an eye-tracking task. Although children, like in previous studies to date, were successfully able to anticipate upcoming spoken language input, there was a strong positive correlation between children's word reading skills (but not their pseudo-word reading and meta-phonological awareness or their spoken word recognition skills) and their prediction skills. We suggest that these findings are most compatible with the notion that the process of learning orthographic representations during reading acquisition sharpens pre-existing lexical representations, which in turn also supports anticipation of upcoming spoken words. © 2014 Elsevier Inc.

Rothenberger A.,University of Gottingen
Behavioral and Brain Sciences | Year: 2012

The closeness of somatosensory phenomena and emotional states can be critically extended into a clinical perspective by referring to Tourette's Syndrome (TS). Two examples are discussed in this commentary: (1) the neurodevelopmental approach to the pre-and post-tic sensorimotor urges, and (2) the TS treatment with deep brain stimulation. It is shown that in TS, both views (locationist and constructionist) need to be combined along the lifespan in order to get a more realistic picture of the brain basis of emotion. © 2012 Cambridge University Press.

Bandelow B.,University of Gottingen
Modern Trends in Pharmacopsychiatry | Year: 2015

In this article, the co-occurrence of anxiety disorders (in particular generalized anxiety disorder) and pain conditions is described, characteristics of chronic pain are explained, and data on the prevalence of co-comorbidity of both conditions are reviewed. Further, hypotheses on the possible psychosocial and neurobiological backgrounds of the high rate of co-occurrence are discussed. This review will also focus on the role of 'unexplained' pain syndromes (e.g. somatic symptom disorder and fibromyalgia) and anxiety. Finally, we address possible treatment strategies for patients with both conditions. There is a need for a rigorous assessment of pain syndromes in generalized anxiety disorder and anxiety in chronic pain conditions in order to prevent subsequent mortality by early treatment of both conditions. © 2015 S. Karger AG, Basel.

Ackermann L.,University of Gottingen
Chemical Reviews | Year: 2011

The development and scope of carboxylates as cocatalysts in transition-metal-catalyzed C-H functionalizations is reviewed. Ryabov and co-workers probed the mechanism of ortho-palladation reactions with N,N-dimethylbenzylamines (DMBA-H, 5) as substrate. Jones and coworkers performed detailed mechanistic studies on the formation of irida- and rhodacycles derived from electron-rich and electron-poor imines, which indicated [Cp*M(OAc)]+ (M = Rh, Ir) to be the key intermediates for acetate-assisted electrophilic activations via transition state. Intermolecular palladium-catalyzed direct benzylations of various five-membered heteroarenes through carboxylate assistance were reported by Fagnou and Lapointe. Dixneuf and Pozgan also reported a ruthenium-catalyzed direct arylation of one 2-phenylpyridine with KOAc as additive.

Sheldrick G.M.,University of Gottingen
Acta Crystallographica Section D: Biological Crystallography | Year: 2010

The programs SHELXC, SHELXD and SHELXE are designed to provide simple, robust and efficient experimental phasing of macromolecules by the SAD, MAD, SIR, SIRAS and RIP methods and are particularly suitable for use in automated structure-solution pipelines. This paper gives a general account of experimental phasing using these programs and describes the extension of iterative density modification in SHELXE by the inclusion of automated protein main-chain tracing. This gives a good indication as to whether the structure has been solved and enables interpretable maps to be obtained from poorer starting phases. The autotracing algorithm starts with the location of possible seven-residue - helices and common tripeptides. After extension of these fragments in both directions, various criteria are used to decide whether to accept or reject the resulting poly-Ala traces. Noncrystallographic symmetry (NCS) is applied to the traced fragments, not to the density. Further features are the use of a no-go map to prevent the traces from passing through heavy atoms or symmetry elements and a splicing technique to combine the best parts of traces (including those generated by NCS) that partly overlap.

Oliveira A.S.,University of Aalborg | Gizzi L.,University Hospital Gdttingen | Farina D.,University of Gottingen | Kersting U.G.,University of Aalborg
Frontiers in Human Neuroscience | Year: 2014

Locomotion can be investigated by factorization of electromyographic (EMG) signals, e.g., with non-negative matrix factorization (NMF). This approach is a convenient concise representation of muscle activities as distributed in motor modules, activated in specific gait phases. For applying NMF, the EMG signals are analyzed either as single trials, or as averaged EMG, or as concatenated EMG (data structure). The aim of this study is to investigate the influence of the data structure on the extracted motor modules. Twelve healthy men walked at their preferred speed on a treadmill while surface EMG signals were recorded for 60s from 10 lower limb muscles. Motor modules representing relative weightings of synergistic muscle activations were extracted by NMF from 40 step cycles separately (EMGSNG), from averaging 2, 3, 5, 10, 20, and 40 consecutive cycles (EMGAVR), and from the concatenation of the same sets of consecutive cycles (EMGCNC). Five motor modules were sufficient to reconstruct the original EMG datasets (reconstruction quality >90%), regardless of the type of data structure used. However, EMGCNC was associated with a slightly reduced reconstruction quality with respect to EMGAVR. Most motor modules were similar when extracted from different data structures (similarity >0.85). However, the quality of the reconstructed 40-step EMGCNC datasets when using the muscle weightings from EMGAVR was low (reconstruction quality ~40%). On the other hand, the use of weightings from EMGCNC for reconstructing this long period of locomotion provided higher quality, especially using 20 concatenated steps (reconstruction quality ~80%). Although EMGSNG and EMGAVR showed a higher reconstruction quality for short signal intervals, these data structures did not account for step-to-step variability. The results of this study provide practical guidelines on the methodological aspects of synergistic muscle activation extraction from EMG during locomotion. © 2014 Oliveira, Gizzi, Farina and Kersting.

Schulz-Schaeffer W.J.,University of Gottingen
Basal Ganglia | Year: 2014

Currently, the pathophysiology of Parkinson's disease is explained by a loss of mainly dopaminergic nerve cells which causes a neurotransmitter deficiency. In the final stage, the substantia nigra shows a marked loss of neurons in Parkinson's disease. In some of the remaining neurons, Lewy bodies can be found and serve as pathological hallmark of disease. These Lewy bodies are composed mainly of aggregated α-synuclein, a protein, physiologically found at pre-synapses. Lewy bodies were thought to be the pathophysiologically relevant form of α-synuclein pathology because their presence coincides with neuron loss in the substantia nigra. As the clinical symptoms suggest a synaptic pathology, involvement of the pre-synapses in the α-synuclein aggregate pathology has been found recently. One to two orders of magnitude more α-synuclein aggregates than Lewy bodies or Lewy neurites can be found at pre-synapses. A degeneration of dendritic spines associated with the synaptic α-synuclein aggregate pathology has been shown to occur in human disease. In experiments using transgenic mice or cell cultures, mild (two- to threefold) overexpression of α-synuclein caused an altered vesicle turnover and led to a reduction in neurotransmitter release. Different approaches linked these alterations to pre-synaptic aggregation of α-synuclein. These findings may change the pathophysiological concept of Parkinson's disease fundamentally. Not nerve cell loss but the synaptic dysfunction of still existing nerve cells should become the focus of attention. Future strategies for therapies should concentrate on the maintenance of synapses rather than focusing on the mechanism of cell death or cell replacement strategies. © 2014 Elsevier GmbH.

Meinhold G.,University of Gottingen | Morton A.C.,University of Cambridge | Morton A.C.,HM Research Associates | Avigad D.,Hebrew University of Jerusalem
Gondwana Research | Year: 2013

We present a synopsis of detrital zircon U-Pb ages of sandstones from North Africa and neighboring Israel and Jordan, which allows us to identify zones with characteristic sediment provenance along the northern Gondwana margin (in present-day coordinates) in Cambrian-Ordovician times, and helps us to unravel the peri-Gondwana jigsaw puzzle. A special feature of the early Paleozoic cover sequence of North Africa is the eastward increase of 1.1-0.95. Ga detrital zircons, which become ubiquitous in the early Paleozoic sandstones of the Saharan Metacraton. Detrital zircons aged about 2.7-2.5, 2.15-1.75 and 0.75-0.53. Ga are also present. Early Paleozoic sandstones with similar provenance are known from peri-Gondwana terranes in the Eastern and Western Mediterranean and from NW Iberia. These terranes need not be transported from western Gondwana (Amazonia) as suggested previously. They were likely located to the north of the Saharan Metacraton during the early Paleozoic before they rifted off from Gondwana. Furthermore, we recognize an increase, as stratigraphic ages get younger, of ca. 1.0. Ga detrital zircons at some point between the Late Cambrian and late Middle Ordovician. We speculate that this might be linked to far-field tectonics and regional uplift in central Gondwana related to plate-tectonic reorganization along the Gondwana margin, leading to erosion of ca. 1.0. Ga basement and country rocks of the Transgondwanan supermountain and fluvial dispersal of detritus toward the Gondwana margin. © 2012 International Association for Gondwana Research.

Ozener B.,Cumhuriyet University | Fink B.,University of Gottingen
Evolution and Human Behavior | Year: 2010

Deviations from perfect symmetry in paired traits of otherwise bilateral symmetrical organisms are thought to reflect developmental quality, especially the ability to resist environmental perturbations early in ontogeny. It is well established that poor environmental conditions increase developmental instability (DI) as reflected by measurements of fluctuating asymmetry. In humans, there is evidence that DI relates to numerous fitness components, and studies have found that perceptions of facial attractiveness for example are positively correlated with measurements of facial symmetry. Here we report the data on measurements of facial symmetry of 503 Turkish senior year high school students aged 17 to 18 years, of whom 133 males and 117 females were recruited from a slum district of Şentepe in Ankara (Group 1), and 131 males and 122 females from three high schools in wealthy central urban areas (Group 2). Digital images were used to assess the degree of facial asymmetry as measured from seven paired traits and calculated as a composite score. Facial asymmetry of participants in Group 1 (slum district) was significantly higher than that of participants in Group 2 (urban areas). Moreover, males in Group 1 were found to have higher facial asymmetry than females, while no sex difference was observed in Group 2. We conclude that poor living conditions have an influence on DI in humans, which manifests itself in the form of facial asymmetry, and that this might be particularly true for males. © 2010 Elsevier Inc.

Reiners A.,University of Gottingen
Living Reviews in Solar Physics | Year: 2012

Cool stars like the Sun harbor convection zones capable of producing substantial surface magnetic fields leading to stellar magnetic activity. The influence of stellar parameters like rotation, radius, and age on cool-star magnetism, and the importance of the shear layer between a radiative core and the convective envelope for the generation of magnetic fields are keys for our understanding of low-mass stellar dynamos, the solar dynamo, and also for other large-scale and planetary dynamos. Our observational picture of cool-star magnetic fields has improved tremendously over the last years. Sophisticated methods were developed to search for the subtle effects of magnetism, which are difficult to detect particularly in cool stars. With an emphasis on the assumptions and capabilities of modern methods used to measure magnetism in cool stars, I review the different techniques available for magnetic field measurements. I collect the analyses on cool-star magnetic fields and try to compare results from different methods, and I review empirical evidence that led to our current picture of magnetic fields and their generation in cool stars and brown dwarfs.

Kochukhov O.,Uppsala University | Wade G.A.,Royal Military College of Canada | Shulyak D.,University of Gottingen
Monthly Notices of the Royal Astronomical Society | Year: 2012

Magnetic Doppler imaging is currently the most powerful method of interpreting high-resolution spectropolarimetric observations of stars. This technique has provided the very first maps of stellar magnetic field topologies reconstructed from time series of full Stokes vector spectra, revealing the presence of small-scale magnetic fields on the surfaces of Ap stars. These studies were recently criticised by Stift et al., who claimed that magnetic inversions are not robust and are seriously undermined by neglecting a feedback on the Stokes line profiles from the local atmospheric structure in the regions of enhanced metal abundance. We show that Stift et al. misinterpreted published magnetic Doppler imaging results and consistently neglected some of the most fundamental principles behind magnetic mapping. Using state-of-the-art opacity sampling model atmosphere and polarized radiative transfer codes, we demonstrate that the variation of atmospheric structure across the surface of a star with chemical spots affects the local continuum intensity but is negligible for the normalized local Stokes profiles except for the rare situation of a very strong line in an extremely Fe-rich atmosphere. For the disc-integrated spectra of an Ap star with extreme abundance variations, we find that the assumption of a mean model atmosphere leads to moderate errors in Stokes I but is negligible for the circular and linear polarization spectra. Employing a new magnetic inversion code, which incorporates the horizontal variation of atmospheric structure induced by chemical spots, we reconstructed new maps of magnetic field and Fe abundance for the bright Ap star α 2CVn. The resulting distribution of chemical spots changes insignificantly compared to the previous modelling based on a single model atmosphere, while the magnetic field geometry does not change at all. This shows that the assertions by Stift et al. are exaggerated as a consequence of unreasonable assumptions and extrapolations, as well as methodological flaws and inconsistencies of their analysis. Our discussion proves that published magnetic inversions based on a mean stellar atmosphere are highly robust and reliable, and that the presence of small-scale magnetic field structures on the surfaces of Ap stars is indeed real. Incorporating horizontal variations of atmospheric structure in Doppler imaging can marginally improve reconstruction of abundance distributions for stars showing very large iron overabundances. But this costly technique is unnecessary for magnetic mapping with high-resolution polarization spectra. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS.

Platen M.,University of Gottingen
Nature Nanotechnology | Year: 2015

Biological molecules that self-assemble and interact with other molecules are attractive building blocks for engineering biological devices. DNA has been widely used for the creation of nanomaterials, but the use of proteins remains largely unexplored. Here, we show that clathrin can form homogeneous and extended two-dimensional lattices on a variety of substrates, including glass, metal, carbon and plastic. Clathrin is a three-legged protein complex with unique self-assembling properties and is relevant in the formation of membrane transport vesicles in eukaryotic cells. We used a fragment of the adaptor protein epsin to immobilize clathrin lattices on the substrates. The lattices span multiple square millimetres with a regular periodicity of 30 nm and can be functionalized via modified subunits of clathrin with either inorganic nanoparticles or active enzymes. The lattices can be stored for months after crosslinking and stabilization with uranyl acetate. They could be dehydrated and rehydrated without loss of function, offering potential applications in sensing and as biosynthetic reactors. © 2015 Nature Publishing Group

Schumacher M.,University of Gottingen
European Physical Journal C | Year: 2010

It is shown that the Quark-Level Linear σ Model (QLLσM) leads to a prediction for the diamagnetic term of the polarizabilities of the nucleon which is in excellent agreement with experimental data. The bare mass of the σ meson is predicted to be mσ=666 MeV and the two-photon width Γ(σ→γγ)=(2.6±0.3) keV. It is argued that the mass predicted by the QLLσM corresponds to the reaction, i. e. to a t-channel pole of the γN→Nγ reaction. Large-angle Compton scattering experiments revealing effects of the σ meson in the differential cross section are discussed. Arguments are presented that these findings may be understood as an observation of the Higgs boson of the strong interaction while being a part of the constituent quark. © Springer-Verlag / Società Italiana di Fisica 2010.

Hardeland R.,University of Gottingen
International Journal of Molecular Sciences | Year: 2014

Melatonin is a highly pleiotropic regulator molecule, which influences numerous functions in almost every organ and, thus, up- or down-regulates many genes, frequently in a circadian manner. Our understanding of the mechanisms controlling gene expression is actually now expanding to a previously unforeseen extent. In addition to classic actions of transcription factors, gene expression is induced, suppressed or modulated by a number of RNAs and proteins, such as miRNAs, lncRNAs, piRNAs, antisense transcripts, deadenylases, DNA methyltransferases, histone methylation complexes, histone demethylases, histone acetyltransferases and histone deacetylases. Direct or indirect evidence for involvement of melatonin in this network of players has originated in different fields, including studies on central and peripheral circadian oscillators, shift work, cancer, inflammation, oxidative stress, aging, energy expenditure/obesity, diabetes type 2, neuropsychiatric disorders, and neurogenesis. Some of the novel modulators have also been shown to participate in the control of melatonin biosynthesis and melatonin receptor expression. Future work will need to augment the body of evidence on direct epigenetic actions of melatonin and to systematically investigate its role within the network of oscillating epigenetic factors. Moreover, it will be necessary to discriminate between effects observed under conditions of well-operating and deregulated circadian clocks, and to explore the possibilities of correcting epigenetic malprogramming by melatonin. © 2014 by the authors; licensee MDPI, Basel, Switzerland.

Bayer T.A.,University of Gottingen
European Neuropsychopharmacology | Year: 2015

The current review covers proteinopathies an umbrella term for neurodegenerative disorders that are characterized by the accumulation of specific proteins within neurons or in the brain parenchyma. Most prevalent examples for typical proteinopathies are Alzheimer's disease and Parkinson's disease. In healthy brain, these proteins are unstructured as a monomer, serving most likely as the physiological form. In a disease condition, the unstructured proteins experience a conformational change leading to small oligomers that eventually will aggregate into higher order structures. Prion disease is an exception within the family of proteinopathies as the aggregated prion protein is highly infectious and can self-aggregate and propagate. Recent reports might implicate a prion-like spread of misfolded proteins in Alzheimer's and Parkinson's disease; however there are evident differences in comparison to prion diseases. As proteinopathies are caused by the aggregation of disease-typical proteins with an ordered structure, active and passive immunization protocols have been used to expose model systems to therapeutic antibodies that bind to the aggregates thereby inhibiting the prolongation into higher ordered fibrils or dissolving the existing fibrillar structure. While most of the immunization treatments have been only carried out in preclinical model systems overexpressing the disease-relevant aggregating protein, other approaches are already in clinical testing. Taking the core concept of proteinopathies with conformationally altered protein aggregates into account, immunization appears to be a very promising therapeutic option for neurodegenerative disorders. © 2013 Elsevier B.V. and ECNP.

Bai H.,University of Gottingen
PloS one | Year: 2013

Nitrate is an important nutrient required for plant growth. It also acts as a signal regulating plant development. Nitrate is actively taken up and transported by nitrate transporters (NRT), which form a large family with many members and distinct functions. In contrast to Arabidopsis and rice there is little information about the NRT family in woody plants such as Populus. In this study, a comprehensive analysis of the Populus NRT family was performed. Sixty-eight PtNRT1/PTR, 6 PtNRT2, and 5 PtNRT3 genes were identified in the P. trichocarpa genome. Phylogenetic analysis confirmed that the genes of the NRT family are divided into three clades: NRT1/PTR with four subclades, NRT2, and NRT3. Topological analysis indicated that all members of PtNRT1/PTR and PtNRT2 have 8 to 12 trans-membrane domains, whereas the PtNRT3 proteins have no or up to two trans-membrane domains. Four PtNRT3 members were predicted as secreted proteins. Microarray analyses revealed tissue-specific expression patterns of PtNRT genes with distinct clusters of NRTs for roots, for the elongation zone of the apical stem segment and the developing xylem and a further cluster for leaves, bark and wood. A comparison of different poplar species (P. trichocarpa, P. tremula, P. euphratica, P. fremontii x P. angustifolia, and P. x canescens) showed that the tissue-specific patterns of the NRT genes varied to some extent with species. Bioinformatic analysis of putative cis-regulatory elements in the promoter regions of PtNRT family retrieved motifs suggesting the regulation of the NRT genes by N metabolism, by energy and carbon metabolism, and by phytohormones and stress. Multivariate analysis suggested that the combination and abundance of motifs in distinct promoters may lead to tissue-specificity. Our genome wide analysis of the PtNRT genes provides a valuable basis for functional analysis towards understanding the role of nitrate transporters for tree growth.

Negative experiences during the course of medical education have been reported in many countries, but little is known about the perceived severity of these experiences. We studied for the first time how often students at a medical university in Germany have had negative experiences, and how severe they perceive these to be. We asked medical students in an online survey whether they felt adequately appreciated, had experienced peer rivalry, verbal abuse by their mentors, physical abuse or mistreatment, sexual harassment, racial or ethnic discrimination, or any other kind of mistreatment. Of 391 students, 56% stated that they felt insufficiently appreciated, 51% had experienced rivalry, and 34% had suffered verbal abuse. Fifty-nine percent of the students felt highly aggrieved because of verbal abuse, while 46% were aggrieved by the ongoing rivalry and 32% by the lack of appreciation. Significantly fewer students felt upset because they were passed over or ignored (21%). Generally, female students felt more often aggrieved by these negative experiences than their male colleagues. Of the possible negative experiences, the less prominent ones such as lack of appreciation or verbal abuse are not only frequent, they are also perceived as very upsetting. Medical teachers should reflect this more in their day-to-day dealings with students and aim to improve on their contact with the students accordingly.

Stark H.,MPI for Biophysical Chemistry | Stark H.,University of Gottingen
Methods in Enzymology | Year: 2010

Here, we review the GraFix (Gradient Fixation) method to purify and stabilize macromolecular complexes for single particle cryo-electron microscopy (cryo-EM). During GraFix, macromolecules undergo a weak, intramolecular chemical cross-linking while being purified by density gradient ultracentrifugation. GraFix-stabilized particles can be used directly for negative-stain cryo-EM or, after a brief buffer-exchange step, for unstained cryo-EM. This highly reproducible method has proved to dramatically reduce problems in heterogeneity due to particle dissociation during EM grid preparation. Additionally, there is often an appreciable increase in particles binding to the carbon support film. This and the fact that binding times can be drastically increased, with no apparent disruption of the native structures of the macromolecules, makes GraFix a method of choice when preparing low-abundance complexes for cryo-EM. The higher sample quality following GraFix purification is evident when examining raw images, which usually present a low background of fragmented particles, good particle dispersion, and high-contrast, well-defined particles. Setting up the GraFix method is straightforward, and the resulting improvement in sample homogeneity has been beneficial in successfully obtaining the 3D structures of numerous macromolecular complexes by cryo-EM in the past few years. © 2010 Elsevier Inc.

Roesky H.W.,University of Gottingen
Journal of Organometallic Chemistry | Year: 2013

The preparation of NHC·SiCl2 and its reaction with various reagents is reported (NHC = N-heterocyclic carbene). A comparable reaction is used for preparing LSiCl from LSiHCl2 and NHC (L = PhC(NtBu)2). The reduction of LSiCl results in the formation of the inter-connected bis-silylene of composition LSi:-Si:L. The latter compound reacts with P4 and AdCP to LSiP2SiL and LSi(Ad)CPSiL, respectively. Treatment of NHC·SiCl2 with 2,6-Ar 2C6H3N3 (Ar = 2,6-iPr 2C6H3 or 2,4,6-iPr3C 6H2) resulted in the NHC·(SiCl2)N2,6- Ar2C6H3. The reduction of the latter yields the bis-silylene. This cyclic bis-silylene of composition (2,6-Ar2C 6H3NSi:)2 contains a four-membered N 2Si2 ring with two coordinate silicon. Treatment of LSiN(SiMe3)2 with P4 results in the acyclic 6π system L((Me3Si)2N)SiP-PP-PSi(N(SiMe 3)2)L under opening of the P4 tetraeder. Metal complexes of silylenes with Co, V, and Ni are reported. © 2013 Elsevier B.V. All rights reserved.

Bruck W.,University of Gottingen | Zamvil S.S.,University of California at San Francisco
Expert Review of Clinical Pharmacology | Year: 2012

Laquinimod is a novel, small, orally administered medication that has demonstrated efficacy in the treatment of multiple sclerosis, a chronic inflammatory demyelinating disease of the CNS. In preclinical testing, laquinimod inhibited the development of both acute and chronic paralysis in the multiple sclerosis model, experimental autoimmune encephalomyelitis. Furthermore, laquinimod reduced inflammation, demyelination and axonal damage in experimental autoimmune encephalomyelitis in mice treated at disease induction or at clinical disease onset. Recent findings from the clinical trials indicate that laquinimod has significant effects in reducing relapse rate and has more pronounced effects in reducing sustained disability progression as well as brain atrophy, with a good safety profile. In conclusion, preclinical studies show that laquinimods unique mechanisms of action, including its immunomodulatory and CNS-protective effects, translate into clinical benefits in relapsing-remitting multiple sclerosis patients. © 2012 Expert Reviews Ltd.

Gehringer A.,University of Gottingen
International Journal of Production Economics | Year: 2015

This paper investigates the impact of the financial integration process on economic growth. Specifically, in analysing such growth effects, the distinction is made between two growth channels - investment and productivity. Crucially, the analysis tests whether the effects of financial openness on services differ from its effects on manufacturing. Based on a panel of sector-level data (manufacturing and services) from the EU KLEMS database (1980-2009), such effects are estimated in a dynamic panel setting. The main findings suggest that the productivity effects of financial integration, although positive overall, are uneven and they differ between the manufacturing and service sectors. More precisely, the results confirm that the manufacturing sector could profit from the process of global financial integration to a greater extent than services. But the impact of financial globalization on service sectors productivity remains overall positive. On the contrary, capital accumulation was broadly unaffected. Such results remain robust to different sensitivity checks regarding, most importantly, the measurement of financial integration. The findings of the lower productivity impact in services can be understood considering their more intensive skill-biased direction of technological change. At the same time, the strong capital-skills complementarity in services sustained the generation of positive expectations over future productivity growth and attracted financial resources from abroad. As an implication of this research and given the increasing importance of service sectors to modern economic systems, the focus should be placed on searching for more precise channels of long-lasting growth in services. (JEL: F02, F21, F36, F4) © 2014 Elsevier B.V. All rights reserved.

Sulieman S.,University of Gottingen
Plant signaling & behavior | Year: 2011

The ability to regulate the rates of metabolic processes in response to changes in the internal and/or external environment is a fundamental feature which is inherent in all organisms. This adaptability is necessary for conserving the stability of the intercellular environment (homeostasis) which is essential for maintaining an efficient functional state in the organism. Symbiotic nitrogen fixation in legumes is an important process which establishes from the complex interaction between the host plant and microorganism. This process is widely believed to be regulated by the host plant nitrogen demand through a whole plant N feedback mechanism in particular under unfavorable conditions. This mechanism is probably triggered by the impact of shoot-borne, phloem-delivered substances. The precise mechanism of the potential signal is under debate, however, the whole phenomenon is probably related to a constant amino acid cycling within the plant, thereby signaling the shoot nitrogen status. Recent work indicating that there may be a flow of nitrogen to bacteroids is discussed in light of hypothesis that such a flow may be important to nodule function. Large amount of γ-aminobutyric acid (GABA) are cycled through the root nodules of the symbiotic plants. In this paper some recent evidence concerning the possible role of GABA in whole-plant-based up regulation of symbiotic nitrogen fixation will be reviewed.

Sowa H.,University of Gottingen | Fischer W.,University of Marburg
Acta Crystallographica Section A: Foundations of Crystallography | Year: 2010

All homogeneous sphere packings and all interpenetrating layers of spheres were derived that refer to the 18 orthorhombic trivariant lattice complexes with mirror symmetry. In total, sphere packings of 51 different types have been found. Only for 28 of these types is the maximal inherent symmetry of their sphere packings orthorhombic. Some crystal structures that can be described by means of sphere packings are listed. © 2010 International Union of Crystallography. Printed in Singapore-all rights reserved.

Propastin P.,University of Gottingen
International Journal of Geographical Information Science | Year: 2011

This article aims to explore spatial and altitudinal non-stationarity in the relationship between aboveground biomass (AGB) of tropical rainforest in Sulawesi (Indonesia) and topography. An autoregressive model through a geographically weighted regression (GWR) framework was used to study the relationship between ground-measured values of AGB and altitude above sea level at 85 sampling plots. The relationships between AGB and altitude were found to be significantly spatially variable and scale-dependent. The results also suggested high altitudinal variability in the examined relationship. Both the strength of the AGB-altitude relationship (ρ) and the altitudinal gradient (α) showed a high changeability in the horizontal and vertical dimensions. The complex spatioaltitudinal patterns in the GWR-based local estimates of the ρ and α parameters gave rise to both spatial and altitudinal variations in the scale effects. The approach presented in this study enables finding the most appropriate scale for data analysis within different altitudinal bands. The study found that the changes of the gradient a along altitudinal transects relate to prevalent environmental conditions observed at different altitudes, whereas the optimal bandwidth was related to the terrain surface heterogeneity. © 2011 Taylor & Francis.

Jehle J.-M.,University of Gottingen
Forensische Psychiatrie, Psychologie, Kriminologie | Year: 2013

Spectacular trials leading to alleged or proven wrongful convictions arouse the concern of the German public. In spite of that there is no current systematic analysis of sources of error in criminal procedures. This article defines what may be recognized as a wrongful conviction or wrongful decision and gives an account of studies on wrongful convictions in America and some European countries. Concerning the German situation, firstly possible sources of error in preliminary proceedings are highlighted and then the outcomes of appeals are analyzed, thus estimating the quantity of wrongful convictions by courts in the first instance on the basis of statistical data. Furthermore, the very restrictive prerequisites for retrials are discussed. Concluding, the author argues for a systematic empirical analysis of sources of error in criminal proceedings and a facilitation of the prerequisites for retrials. © 2013 Springer-Verlag Berlin Heidelberg.

Jakobs S.,Max Planck Institute for Biophysical Chemistry | Jakobs S.,University of Gottingen | Wurm C.A.,Max Planck Institute for Biophysical Chemistry
Current Opinion in Chemical Biology | Year: 2014

Mitochondria, the powerhouses of the cell, are essential organelles in eukaryotic cells. With their complex inner architecture featuring a smooth outer and a highly convoluted inner membrane, they are challenging objects for microscopy. The diameter of mitochondria is generally close to the resolution limit of conventional light microscopy, rendering diffraction-unlimited super-resolution light microscopy (nanoscopy) for imaging submitochondrial protein distributions often mandatory. In this review, we discuss what can be expected when imaging mitochondria with conventional diffraction-limited and diffraction-unlimited microscopy. We provide an overview on recent studies using super-resolution microscopy to investigate mitochondria and discuss further developments and challenges in mitochondrial biology that might by addressed with these technologies in the future. © 2014 The Authors.

Gollisch T.,University of Gottingen
Journal of Physiology Paris | Year: 2013

Ganglion cells in the vertebrate retina integrate visual information over their receptive fields. They do so by pooling presynaptic excitatory inputs from typically many bipolar cells, which themselves collect inputs from several photoreceptors. In addition, inhibitory interactions mediated by horizontal cells and amacrine cells modulate the structure of the receptive field. In many models, this spatial integration is assumed to occur in a linear fashion. Yet, it has long been known that spatial integration by retinal ganglion cells also incurs nonlinear phenomena. Moreover, several recent examples have shown that nonlinear spatial integration is tightly connected to specific visual functions performed by different types of retinal ganglion cells. This work discusses these advances in understanding the role of nonlinear spatial integration and reviews recent efforts to quantitatively study the nature and mechanisms underlying spatial nonlinearities. These new insights point towards a critical role of nonlinearities within ganglion cell receptive fields for capturing responses of the cells to natural and behaviorally relevant visual stimuli. In the long run, nonlinear phenomena of spatial integration may also prove important for implementing the actual neural code of retinal neurons when designing visual prostheses for the eye. © 2012 Elsevier Ltd.

Musshoff O.,University of Gottingen
Biomass and Bioenergy | Year: 2012

In many cases decision-makers apparently do not adapt as fast as expected to changing economic conditions. This is also the case for the conversion of farm land to short rotation coppice. From an economic point of view, short rotation coppice has become more interesting in the last few years. Nevertheless, farm land still is rarely used to grow this quite unknown crop. Several explanatory approaches (e.g., traditionalistic behavior and risk aversion) are currently discussed in order to explain this behavior. A relatively new explanatory approach is the Real Options Approach. The Real Options Approach uses a comprehensive dynamic-stochastic model that combines the uncertainty of investment returns, the sunk costs, and the temporal flexibility of the investment implementation. The quintessence of the Real Options Approach is that-compared to the Classical Investment Theory-the investment triggers will be shifted upwards if investments involve intertemporal opportunity costs. This paper develops a real options model which allows the determination of triggers on the basis of realistic assumptions. We examined when farmers, who only dispose of sandy soils with little water-storing capacity, should convert set-aside land to short rotation coppice. The results show that farmers should not convert until the present value of the investment returns exceeds the investment costs considerably. Thus, they confirm the empirically observed reluctance in conversion. Furthermore, it turned out that the magnitude of the difference between the Classical Investment Theory and the Real Options Approach depends heavily on the type of stochastic process that underlies the investment returns. © 2012 Elsevier Ltd.

Transcranial alternating current stimulation (tACS) is a non-invasive stimulation technique for shaping neuroplastic processes and possibly entraining ongoing neural oscillations in humans. Despite the growing number of studies using tACS, we know little about the procedural sensations caused by stimulation. In order to fill this gap, we explored the cutaneous sensation and phosphene perception during tACS. Twenty healthy participants took part in a randomized, single-blinded, sham-controlled study, where volunteers received short duration stimulation at 1.0 mA intensity between 2 to 250 Hz using the standard left motor cortex-contralateral supraorbital montage. We recorded the perception onset latency and the strength of the sensations assessed by visual rating scale as dependent variables. We found that tACS evoked both cutaneous sensation and phosphene perception in a frequency-dependent manner. Our results show that the most perceptible procedural sensations were induced in the beta and gamma frequency range, especially at 20 Hz, whereas minimal procedural sensations were indicated in the ripple range (140 and 250 Hz). We believe that our results provide a relevant insight into the procedural sensations caused by oscillatory currents, and will offer a basis for developing more sophisticated stimulation protocols and study designs for future investigations.

Kramer S.,University of Gottingen
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

A finite-element method is presented for calculating the quantum conductance of mesoscopic two-dimensional electron devices of complex geometry attached to semi-infinite leads. For computational purposes, the leads must be cut off at some finite length. To avoid spurious, unphysical reflections, this is modeled by transparent boundary conditions. We introduce the Hardy space infinite-element technique from acoustic scattering as a way of setting up transparent boundary conditions for transport computations spanning the range from the quantum mechanical to the quasiclassical regime. These boundary conditions are exact even for wave packets and thus are especially useful in the limit of high energies with many excited modes. Yet, they possess a memory-friendly sparse matrix representation. In addition to unbounded domains, Hardy space elements allow us to truncate those parts of the computational domain which are irrelevant for the calculation of the transport properties. Thus, the computation can be done only on the region that is essential for a physically meaningful simulation of the scattering states. The benefits of the method are demonstrated by three examples. The convergence properties are tested on the transport through a quasi-one-dimensional quantum wire. It is shown that higher-order finite elements considerably improve current conservation and establish the correct phase shift between the real and the imaginary parts of the electron wave function. The Aharonov-Bohm effect demonstrates that characteristic features of quantum interference can be assessed. A simulation of electron magnetic focusing exemplifies the capability of the computational framework to study the crossover from quantum to quasiclassical behavior. © 2013 American Physical Society.

Parkinson's disease (PD) and dementia with Lewy bodies (DLB) are usually associated with loss of dopaminergic neurons. Loss of substantia nigra neurons and presence of Lewy body inclusions in some of the remaining neurons are the hallmark pathology seen in the final stages of the disease. Attempts to correlate Lewy body pathology to either cell death or severity of clinical symptoms, however, have not been successful. While the pathophysiology of the neurodegenerative process can hardly be explained by Lewy bodies, the clinical symptoms do indicate a degenerative process located at the presynapse resulting in a neurotransmitter deficiency. Recently it was shown that 90% or even more of α-synuclein aggregates in DLB cases were located at the presynapses in the form of very small deposits. In parallel, dendritic spines are retracted, whereas the presynapses are relatively preserved, suggesting a neurotransmitter deprivation. The same α-synuclein pathology can be demonstrated for PD. These findings give rise to the notion that not cell death but rather α-synuclein aggregate-related synaptic dysfunction causes the neurodegeneration. This opens new perspectives for understanding PD and DLB. If presynaptic α-synuclein aggregation, not neuronal loss, is the key issue of the neurodegenerative process, then PD and DLB may eventually be treatable in the future. The disease may progress via trans-synaptical spread, suggesting that stem cell transplants are of limited use. Future therapies may focus on the regeneration of synapses. © The Author(s) 2010.

Paulus W.,University of Gottingen
Nature Reviews Neurology | Year: 2010

Restless legs syndrome (RLS) is a somatosensory network disorder that is clinically diagnosed according to four main criteria: an urge to move the legs, usually associated with unpleasant leg sensations; induction or exacerbation of symptoms by rest; symptom relief on activity; and diurnal fluctuations in symptoms with worsening in the evening and at night. Genetic variants in four chromosomal regions have been identified that increase the risk of RLS. In addition, various different lesions, ranging from peripheral neuropathies to spinal cord lesions or alterations of brain metabolism, are implicated in RLS. In most cases, sleep disorders with frequent sleep fragmentation and characteristic periodic limb movements during sleep can be identified during a polysomnographic recording. The first-line drugs for RLS are dopaminergic agents, which are effective in low to moderate doses. Alternative or additional treatments include opioids and anticonvulsants. Augmentationparadoxical worsening of symptoms by dopaminergic treatmentis the main problem encountered in difficult-to-treat patients. Iron deficiency must be identified and treated by supplementation, both to improve RLS symptoms and to potentially lower the risk of augmentation. Here, we review the latest studies pertaining to the pathophysiology, clinical presentation and management of RLS. © 2010 Macmillan Publishers Limited. All rights reserved.

Lankeit M.,University of Gottingen | Konstantinides S.,Democritus University of Thrace
Thrombosis and Haemostasis | Year: 2010

Patients with high-risk pulmonary embolism (PE), i.e. those with shock or hypotension at presentation, are at high risk of in-hospital death, particularly during the first hours after admission. A meta-analysis of trials which included haemodynamically compromised patients indicated that thrombolytic treatment significantly reduces the rate of inhospital death or PE recurrence. Therefore, thrombolysis should be administered to patients with high-risk PE unless there are absolute contraindications to its use. Uncontrolled data further suggest that thrombolysis may be a safe and effective alternative to surgery in patients with PE and free-floating thrombi in the right heart. On the other hand, normotensive patients generally have a favourable short-term prognosis if heparin anticoagulation is instituted promptly, and they are thus considered to have non-high-risk PE. Generally, the bleeding risk of thrombolysis appears to outweigh the clinical benefits of this treatment in patients without haemodynamic compromise. However, within the group of normotensive patients with PE, some may have evidence of right ventricular dysfunction on echocardiography or computed tomography, or of myocardial injury based on elevated cardiac biomarkers (troponin I or T, heart-type fatty acid-binding protein). These patients have an intermediate risk of an adverse outcome in the acute phase of PE. Existing data suggest that selected patients with intermediate-risk PE may benefit from early thrombolytic treatment, particularly if they have a low bleeding risk. However, controversy will continue to surround the optimal treatment for this group until the results of a large ongoing thrombolysis trial are available in a few years. © Schattauer 2010.

Hardeland R.,University of Gottingen
Frontiers in Plant Science | Year: 2016

Melatonin has been detected in numerous plant species. A particularly surprising finding concerns the highly divergent levels of melatonin that vary between species, organs and environmental conditions, from a few pg/g to over 20 μg/g, reportedly up to 200 μg/g. Highest values have been determined in oily seeds and in plant organs exposed to high UV radiation. The divergency of melatonin concentrations is discussed under various functional aspects and focused on several open questions. This comprises differences in precursor availability, catabolism, the relative contribution of isoenzymes of the melatonin biosynthetic pathway, and differences in rate limitation by either serotonin N-acetyltransferase or N-acetylserotonin O-methyltransferase. Other differences are related to the remarkable pleiotropy of melatonin, which exhibits properties as a growth regulator and morphogenetic factor, actually debated in terms of auxin-like effects, and as a signaling molecule that modulates pathways of ethylene, abscisic, jasmonic and salicylic acids and is involved in stress tolerance, pathogen defense and delay of senescence. In the context of high light/UV intensities, elevated melatonin levels exceed those required for signaling via stress-related phytohormones and may comprise direct antioxidant and photoprotectant properties, perhaps with a contribution of its oxidatively formed metabolites, such as N1-acetyl-N2-formyl-5-methoxykynuramine and its secondary products. High melatonin levels in seeds may also serve antioxidative protection and have been shown to promote seed viability and germination capacity. © 2016, Hardeland.

Enderlein J.,University of Gottingen
International Journal of Molecular Sciences | Year: 2012

We present a theoretical study on the impact of an interface on the FRET efficiency of a surface-bound acceptor-donor system. The FRET efficiency can be modified by two effects. Firstly, the donor's electromagnetic field at the acceptor's position is changed due to the partial reflection of the donor's field. Secondly, both the donor's and the acceptor's quantum yield of fluorescence can be changed due to the interface-induced enhancement of the radiative emission rate (Purcell effect). Numerical results for a FRET-pair at a glass-water interface are given. © 2012 by the authors; licensee MDPI, Basel, Switzerland.

Maass R.,University of Gottingen | Loffler J.F.,ETH Zurich
Advanced Functional Materials | Year: 2015

The future of metallic glasses as an advanced structural and functional material will to a great extent depend on the understanding and control of their mesoscopic flow defects called shear bands. These defects are sweet-and-sour; sweet because they mediate macroscopic plasticity at room temperature, and sour because they quickly promote failure. In the past decade, fundamental research generated great progress in characterizing the role that shear bands play during plastic deformation of disordered systems, including metallic glasses. Similar to those in many other materials, shear bands in metallic glasses are only active for a very short time, which directed research focus towards topological, structural, chemical, and thermal properties of formed, but inactive shear bands. In this paper, recent progress in directly characterizing the shear-band dynamics in situ during straining experiments is presented. Various shear-banding stages are outlined, including formation, propagation, and arrest, as well as shear-band creep and aging. The results are discussed in a more general context of disordered materials, concluding with a summarizing overview of time-scales involved in shear banding, and describing future research directions that may lead to controlled shear-band plasticity in metallic glasses. Dynamic properties of shear bands are a key element for the design of plastically stable bulk metallic glasses. In this Feature Article, recent progress on in situ characterization of shear-band dynamics is summarized. The aim is to provide a comprehensive understanding of shear-band initiation, propagation, arrest, creep, and aging, and how they determine the plastic flow behavior of bulk metallic glasses. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Muller M.,Laser Laboratorium Gottingen E.V. | Mey T.,Laser Laboratorium Gottingen E.V. | Niemeyer J.,University of Gottingen | Mann K.,Laser Laboratorium Gottingen E.V.
Optics Express | Year: 2014

An extremely compact soft x-ray microscope operating in the "water window" region at the wavelength λ = 2.88 nm is presented, making use of a long-term stable and nearly debris-free laser-induced plasma from a pulsed nitrogen gas jet target. The well characterized soft x-ray radiation is focused by an ellipsoidal grazing incidence condenser mirror. Imaging of a sample onto a CCD camera is achieved with a Fresnel zone plate using magnifications up to 500x. The spatial resolution of the recorded microscopic images is about 100 nm as demonstrated for a Siemens star test pattern. ©2014 Optical Society of America.

Kiel S.,University of Gottingen
Journal of Molluscan Studies | Year: 2013

Twelve species of lucinid bivalves are reported from late Jurassic to late Miocene methane-seep deposits worldwide. Among them, eight species and two genera are new. Amanocina n. gen. includes Nipponothracia yezoensis from the Cenomanian of Japan as type species, Cryptolucina kuhnpassetensis Kelly, 2000 from the Berriasian of Greenland, A. raukumara n. sp. from the Albian of New Zealand and A. colombiana n. sp. from the Oligocene of Colombia. Tehamatea n. gen. includes Lucina ovalis Stanton, 1895 and Lucina colusaensis Stanton, 1895 from the late Jurassic to early Cretaceous of California, T. vocontiana n. sp. from the Hauterivian of southern Europe and T. agirrezabalai n. sp. from the Albian of northern Spain. The new species are: Cubatea awanuiensis from the Albian and Cenomanian of New Zealand, Nymphalucina panochensis from the early Palaeocene of California, Elliptiolucina washingtonia from the late Oligocene of Washington State, USA, and Elongatolucina peckmanni from the Oligocene of Colombia. New combinations are provided for Nipponothracia lomitensis (Olsson, 1931) from the Oligocene of Peru and Elliptiolucina hetzeli (Martin, 1933) from the late Miocene of Indonesia. The anterior adductor muscle scar of Beauvoisina carinata is documented for the first time. The lucinids found at Jurassic and Cretaceous deep-water methane seeps belong to the subfamily Myrteinae and within this to genera that are restricted to the seep environment (Beauvoisina, Tehamatea, Amanocina and Cubatea); shallow-water seeps were inhabited by the codakiine genus Nymphalucina, which is not seep-restricted. Amanocina, Cubatea and Nymphalucina survived into the Cenozoic. Genera that newly colonized deepwater seeps during the Cenozoic include members of both Myrteinae (Elongatolucina, Nipponothracia and Elliptiolucina) and Codakiinae (Epilucina and Lucinoma); the latter are clearly not seep-restricted.©The Author 2013. Published by Oxford University Press on behalf of The Malacological Society of London, all rights reserved.

Beier K.,University of Gottingen
Journal of Medicine and Philosophy (United Kingdom) | Year: 2015

Because it is often argued that surrogacy should not be treated as contractual, the question arises in which terms this practice might then be couched. In this article, I argue that a phenomenology of surrogacy centering on the notion of trust provides a description that is illuminating from the moral point of view. My thesis is that surrogacy establishes a complex and extended reproductive unit the "surrogacy triad" consisting of the surrogate mother, the child, and the intending parents whose constituents are bound together by mutual trustful commitments. Even though a trust-based approach does not provide an ultimate answer to whether surrogacy should be sanctioned or prohibited, it allows for at least some practical suggestions. In particular, I will argue that, under certain conditions, surrogacy is tenable within familial or other significant relationships, and I will stress the necessity of acknowledging the new relationships and moral commitments that result from this practice. © The Author 2015. Published by Oxford University Press, on behalf of the Journal of Medicine and Philosophy Inc. All rights reserved.

Anglada-Escude G.,Carnegie Institution of Washington | Anglada-Escude G.,University of Gottingen | Butler R.P.,Carnegie Institution of Washington
Astrophysical Journal, Supplement Series | Year: 2012

Doppler spectroscopy has uncovered or confirmed all the known planets orbiting nearby stars. Two main techniques are used to obtain precision Doppler measurements at optical wavelengths. The first approach is the gas cell method, which consists of least-squares matching of the spectrum of iodine imprinted on the spectrum of the star. The second method relies on the construction of a stabilized spectrograph externally calibrated in wavelength. The most precise stabilized spectrometer in operation is the High Accuracy Radial velocity Planet Searcher (HARPS), operated by the European Southern Observatory in La Silla Observatory, Chile. The Doppler measurements obtained with HARPS are typically obtained using the cross-correlation function (CCF) technique. This technique consists of multiplying the stellar spectrum by a weighted binary mask and finding the minimum of the product as a function of the Doppler shift. It is known that CCF is suboptimal in exploiting the Doppler information in the stellar spectrum. Here we describe an algorithm to obtain precision radial velocity measurements using least-squares matching of each observed spectrum to a high signal-to-noise ratio template derived from the same observations. This algorithm is implemented in our software HARPS-TERRA (Template-Enhanced Radial velocity Re-analysis Application). New radial velocity measurements on a representative sample of stars observed by HARPS are used to illustrate the benefits of the proposed method. We show that, compared with CCF, template matching provides a significant improvement in accuracy, especially when applied to M dwarfs. © 2012. The American Astronomical Society. All rights reserved..

McLean M.,Harvard - Smithsonian Center for Astrophysics | Berger E.,Harvard - Smithsonian Center for Astrophysics | Reiners A.,University of Gottingen
Astrophysical Journal | Year: 2012

We present a new radio survey of about 100 late-M and L dwarfs undertaken with the Very Large Array. The sample was chosen to explore the role of rotation in the radio activity of ultracool dwarfs. As part of the survey we discovered radio emission from three new objects, 2MASS J0518113 - 310153 (M6.5), 2MASS J0952219 - 192431 (M7), and 2MASS J1314203 + 132001 (M7), and made an additional detection of LP349-25 (M8). Combining the new sample with results from our previous studies and from the literature, we compile the largest sample to date of ultracool dwarfs with radio observations and measured rotation velocities (167 objects). In the spectral type range M0-M6 we find a radio activity-rotation relation, with saturation at L rad/L bol 10-7.5 above vsin i 5kms-1, similar to the relation in Hα and X-rays. However, at spectral types ≳ M7 the ratio of radio to bolometric luminosity increases significantly regardless of rotation velocity, and the scatter in radio luminosity increases. In particular, while the most rapid rotators (vsin i ≳ 20kms-1) exhibit "super- saturation" in X-rays and Hα, this effect is not seen in the radio. We also find that ultracool dwarfs with vsin i ≳ 20kms-1 have a higher radio detection fraction by about a factor of three compared to objects with vsin i ≲ 10kms-1. When measured in terms of the Rossby number (Ro), the radio activity-rotation relation follows a single trend and with no apparent saturation from G to L dwarfs and down to Ro 10-3; in X-rays and Hα there is clear saturation at Ro ≲ 0.1, with super-saturation beyond M7. A similar trend is observed for the radio surface flux (L rad/R 2 *) as a function of Ro. The continued role of rotation in the overall level of radio activity and in the fraction of active sources, and the single trend of L rad/L bol and L rad/R 2 * as a function of Ro from G to L dwarfs, indicates that rotation effects are important in regulating the topology or strength of magnetic fields in at least some fully convective dwarfs. The fact that not all rapid rotators are detected in the radio provides additional support to the idea of dual dynamo states proposed from spectropolarimetric observations. © 2012. The American Astronomical Society. All rights reserved.

Hegerfeldt G.C.,University of Gottingen
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2014

A simple result is found for the optimal protocol of drivings for a general two-level Hamiltonian, which transports a given initial state to a given final state in minimal time, under additional conditions on the drivings. If one of the three possible drivings is unconstrained in strength the problem is analytically completely solvable. A surprise arises for a class of states when one driving is bounded by a constant c and the other drivings are constant. Then, for large c, the optimal driving is of type bang-off-bang and for increasing c one recovers the unconstrained result. However, for smaller c the optimal driving can suddenly switch to bang-bang type. It is also shown that for general states one may have a multistep protocol. The present paper explicitly proves and considerably extends the author's results contained in Phys. Rev. Lett. 111, 260501 (2013)PRLTAO0031-900710.1103/PhysRevLett.111.260501. © 2014 American Physical Society.

Chmyrov A.,Max Planck Institute for Biophysical Chemistry | Keller J.,Max Planck Institute for Biophysical Chemistry | Grotjohann T.,Max Planck Institute for Biophysical Chemistry | Ratz M.,Max Planck Institute for Biophysical Chemistry | And 5 more authors.
Nature Methods | Year: 2013

We show that nanoscopy based on the principle called RESOLFT (reversible saturable optical fluorescence transitions) or nonlinear structured illumination can be effectively parallelized using two incoherently superimposed orthogonal standing light waves. The intensity minima of the resulting pattern act as 'doughnuts', providing isotropic resolution in the focal plane and making pattern rotation redundant. We super-resolved living cells in 120 μm × 100 μm-sized fields of view in <1 s using 116,000 such doughnuts. © 2013 Nature America, Inc. All rights reserved.

Junker A.,University of Gottingen | Hohlfeld R.,Ludwig Maximilians University of Munich | Meinl E.,Ludwig Maximilians University of Munich
Nature Reviews Neurology | Year: 2011

Several hundred microRNAs (miRNAs) fine-tune the expression of approximately half of all human genes. Recent studies have revealed that miRNA profiles in blood cells become altered in multiple sclerosis (MS), and that active and inactive MS lesions have distinct miRNA expression patterns. The dysregulated miRNAs in MS lesions seem to be associated with astrocytes and infiltrating immune cells, and might unleash local macrophages through downregulation of the self-recognition signal CD47. The expression of miRNA-326 in blood cells has been reported to increase during relapses. This miRNA promotes T helper 17 cell differentiation and is highly abundant in active MS lesions. miRNAs are needed for maintenance of the myelin sheath, and the absence of such molecules results in axonal damage in mice. miRNA-219 and other miRNAs promote oligodendrocyte differentiation. Here, we discuss the possible contribution of miRNAs to MS pathogenesis. An improved understanding of this contribution should help to identify novel therapeutic targets and biomarkers for this disease. © 2011 Macmillan Publishers Limited. All rights reserved.

Dressel R.,University of Gottingen
Seminars in Immunopathology | Year: 2011

Pluripotent stem cells hold great promises for regenerative medicine. They might become useful as a universal source for a battery of new cell replacement therapies. Among the major concerns for the clinical application of stem cell-derived grafts are the risks of immune rejection and tumor formation. Pluripotency and tumorigenicity are closely linked features of pluripotent stem cells. However, the capacity to form teratomas or other tumors is not sufficiently described by inherited features of a stem cell line or a stem cell-derived graft. The tumorigenicity always depends on the inability of the recipient to reject the tumorigenic cells. This review summarizes recent data on the tumorigenicity of pluripotent stem cells in immunodeficient, syngeneic, allogeneic, and xenogeneic hosts. The effects of immunosuppressive treatment and cell differentiation are discussed. Different immune effector mechanisms appear to be involved in the rejection of undifferentiated and differentiated cell populations. Elements of the innate immune system, such as natural killer cells and the complement system, which are active also in syngeneic recipients, appear to preferentially reject undifferentiated cells. This effect could reduce the risk of tumor formation in immunocompetent recipients. Cell differentiation apparently increases susceptibility to rejection by the adaptive immune system in allogeneic hosts. The current data suggest that the immune system of the recipient has a major impact on the outcome of pluripotent stem cell transplantation, whether it is rejection, engraftment, or tumor development. This has to be considered when the results of experimental transplantation models are interpreted and even more when translation into clinics is planned. © 2011 The Author(s).

Zahn J.,University of Gottingen
Annales Henri Poincare | Year: 2012

We study infrared divergences due to ultraviolet-infrared mixing in quantum field theory on Moyal space with Lorentzian signature in the Yang-Feldman formalism. Concretely, we are considering the and the model in arbitrary even dimension. It turns out that the situation is worse than in the Euclidean setting, in the sense that we find infrared divergences in graphs that are finite there. We briefly discuss the problems one faces when trying to adapt the nonlocal counterterms that render the Euclidean model renormalizable. © 2011 The Author(s).

Svanadze M.M.,University of Gottingen | Svanadze M.M.,Tbilisi State University
Journal of Elasticity | Year: 2014

In the present paper the linear theory of viscoelasticity for Kelvin-Voigt materials with voids is considered and some basic results of the classical theory of elasticity are generalized. Indeed, the basic properties of plane harmonic waves are established. The explicit expression of fundamental solution of the system of equations of steady vibrations is constructed by means of elementary functions. The Green's formulas in the considered theory are obtained. The uniqueness theorems of the internal and external basic boundary value problems (BVPs) are proved. The representation of Galerkin type solution is obtained and the completeness of this solution is established. The formulas of integral representations of Somigliana type of regular vector and regular (classical) solution are obtained. The Sommerfeld-Kupradze type radiation conditions are established. The basic properties of elastopotentials and singular integral operators are given. Finally, the existence theorems for classical solutions of the internal and external basic BVPs of steady vibrations are proved by using of the potential method (boundary integral method) and the theory of singular integral equations. © 2013 Springer Science+Business Media Dordrecht.

We present a new type of local image descriptor which yields binary patterns from small image patches. For the application to fingerprint liveness detection, we achieve rotation invariant image patches by taking the fingerprint segmentation and orientation field into account. We compute the discrete cosine transform (DCT) for these rotation invariant patches and attain binary patterns by comparing pairs of two DCT coefficients. These patterns are summarized into one or more histograms per image. Each histogram comprises the relative frequencies of pattern occurrences. Multiple histograms are concatenated and the resulting feature vector is used for image classification. We name this novel type of descriptor convolution comparison pattern (CCP). Experimental results show the usefulness of the proposed CCP descriptor for fingerprint liveness detection. CCP outperforms other local image descriptors such as LBP, LPQ and WLD on the LivDet 2013 benchmark. The CCP descriptor is a general type of local image descriptor which we expect to prove useful in areas beyond fingerprint liveness detection such as biological and medical image processing, texture recognition, face recognition and iris recognition, liveness detection for face and iris images, and machine vision for surface inspection and material classification. © 2016 Carsten Gottschlich. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Kaatze U.,University of Gottingen
Chemical Physics Letters | Year: 2012

Literature data for the isentropic compressibility and principal dielectric relaxation time of aqueous solutions of hydrophobic solutes are evaluated to investigate the relative molal shifts B κ and B d, respectively, of these parameters. In general, B κ and B d are correlated: with increasing number of hydrophobic groups per solute, the compressibility decreases and the dielectric relaxation time increases. Effects in the former parameter are smaller than in the latter. Solute isomerisation induces more intricate hydration behaviour. Comparison is also made with results from more complex hydration models, involving both the amount of hydration water and the changes in its relevant parameters. © 2012 Elsevier B.V. All rights reserved.

Schmidt M.,University of Gottingen
Public Transport | Year: 2013

The task of delay management is to decide whether connecting trains should wait for delayed feeder trains or depart on time in order to minimize the passengers' delay. To estimate the effect of the wait-depart decisions on the travel times, most delay management models assume that passengers' routes are predefined. However, in practice, passengers can adapt their routes to the wait-depart decisions and arising changes in the timetable. For this reason, in this paper we assume that passengers' demand is given in form of pairs of origins and destinations (OD-pairs) and take wait-depart decisions and decisions on passengers' routes simultaneously. This approach, called delay management with re-routing, was introduced in Dollevoet et al. (Transp. Sci. 46(1):74-89, 2012) and we build our research upon the results obtained there. We show that the delay management problem with re-routing is strongly NP-hard even if there is only one OD-pair. Furthermore, we prove that even if there are only two OD-pairs, the problem cannot be approximated with constant approximation ratio unless P=NP. However, for the case of only one OD-pair we propose a polynomial-time algorithm. We show that our algorithm finds an optimal solution if there is no reasonably short route from origin to destination which requires a passenger to enter the same train twice. Otherwise, the solution found by the algorithm is a 2-approximation of an optimal solution and the estimated travel time is a lower bound on the objective value. © 2013 Springer-Verlag Berlin Heidelberg.

Noubactep C.,University of Gottingen
Journal of Hazardous Materials | Year: 2010

The further development of Fe0-based remediation technology depends on the profound understanding of the mechanisms involved in the process of aqueous contaminant removal. The view that adsorption and co-precipitation are the fundamental contaminant removal mechanisms is currently facing a harsh scepticism. Results from electrochemical cementation are used to bring new insights in the process of contaminant removal in Fe0/H2O systems. The common feature of hydrometallurgical cementation and metal-based remediation is the heterogeneous nature of the processes which inevitably occurs in the presence of a surface scale. The major difference between both processes is that the surface of remediation metals is covered by layers of own oxide(s) while the surface of the reducing metal in covered by porous layers of the cemented metal. The porous cemented metal is necessarily electronic conductive and favours further dissolution of the reducing metal. For the remediation metal, neither a porous layer nor a conductive layer could be warrant. Therefore, the continuation of the remediation process depends on the long-term porosity of oxide scales on the metal surfaces. These considerations rationalized the superiority of Fe0 as remediation agent compared to thermodynamically more favourable Al0 and Zn0. The validity of the adsorption/co-precipitation concept is corroborated. © 2010 Elsevier B.V.

Goenner H.,University of Gottingen
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2010

A variational principle is suggested within Riemannian geometry, in which an auxiliary metric and the Levi Civita connection are varied independently. The auxiliary metric plays the role of a Lagrange multiplier and introduces nonminimal coupling of matter to the curvature scalar. The field equations are 2nd order PDEs and easier to handle than those following from the so-called Palatini method. Moreover, in contrast to the latter method, no gradients of the matter variables appear. In cosmological modeling, the physics resulting from the alternative variational principle will differ from the modeling using the standard Palatini method. © 2010 The American Physical Society.

Kuss-Petermann M.,University of Gottingen | Wenger O.S.,University of Basel
Journal of Physical Chemistry Letters | Year: 2013

Proton-coupled electron transfer (PCET) with phenols has been investigated in considerable detail in recent years while at the same time analogous mechanistic studies of PCET with thiophenols have remained scarce. We report on PCET between a series of thiophenols and a photoexcited Ru(II) complex, which acts as a combined electron/proton acceptor. Depending on the exact nature of the thiophenol, PCET occurs through different reaction mechanisms. The results are discussed in the context of recent studies of PCET between phenols and photoexcited d6 metal complexes. © 2013 American Chemical Society.

Kaatze U.,University of Gottingen
Journal of Molecular Liquids | Year: 2011

Broadband dielectric spectra of a variety of aqueous solutions are evaluated as to indications of water that may be considered bound. Static permittivity decrements due to depolarizing internal electric fields, from kinetic depolarization, as well as from dielectric saturation are discussed. The latter effect reflects the preferential orientation of water permanent dipole orientations within strong Coulombic field of small ions, especially multivalent cations. Such water may be considered bound even though rapid rotations around the orientation of the electric dipole moment are definitely possible and also a fast exchange of water molecules between the hydration region and the bulk may take place. Water exhibiting large dielectric relaxation times, as typical for regions with large local concentration of foreign matter, may also be named bound. However, no clear evidence for interaction energies exceeding the hydrogen bond energy of pure water has been found. Rather enhanced relaxation times at low water content reflect the small concentration of hydrogen bonding sites and thus low probability density for the formation of a new hydrogen bond. Potential interferences of the water relaxation with relaxations from other molecules or from ionic structures are mentioned briefly. © 2011 Elsevier B.V. All rights reserved.

VeA is the founding member of the velvet superfamily of fungal regulatory proteins. This protein is involved in light response and coordinates sexual reproduction and secondary metabolism in Aspergillus nidulans. In the dark, VeA bridges VelB and LaeA to form the VelB-VeA-LaeA (velvet) complex. The VeA-like protein VelB is another developmental regulator, and LaeA has been known as global regulator of secondary metabolism. In this study, we show that VelB forms a second light-regulated developmental complex together with VosA, another member of the velvet family, which represses asexual development. LaeA plays a key role, not only in secondary metabolism, but also in directing formation of the VelB-VosA and VelB-VeA-LaeA complexes. LaeA controls VeA modification and protein levels and possesses additional developmental functions. The laeA null mutant results in constitutive sexual differentiation, indicating that LaeA plays a pivotal role in inhibiting sexual development in response to light. Moreover, the absence of LaeA results in the formation of significantly smaller fruiting bodies. This is due to the lack of a specific globose cell type (Hülle cells), which nurse the young fruiting body during development. This suggests that LaeA controls Hülle cells. In summary, LaeA plays a dynamic role in fungal morphological and chemical development, and it controls expression, interactions, and modification of the velvet regulators.

Fichtel C.,Behavioral Ecology and Sociobiology Unit | Kappeler P.M.,University of Gottingen
International Journal of Primatology | Year: 2011

The comprehension and usage of primate alarm calls appear to be influenced by social learning. Thus, alarm calls provide flexible behavioral mechanisms that may allow animals to develop appropriate responses to locally present predators. To study this potential flexibility, we compared the usage and function of 3 alarm calls common to 2 closely related sifaka species (Propithecus verreauxi and P. coquereli), in each of 2 different populations with different sets of predators. Playback studies revealed that both species in both of their respective populations emitted roaring barks in response to raptors, and playbacks of this call elicited a specific anti-raptor response (look up and climb down). However, in Verreaux's sifakas, tchi-faks elicited anti-terrestrial predator responses (look down, climb up) in the population with a higher potential predation threat by terrestrial predators, whereas tchi-faks in the other population were associated with nonspecific flight responses. In both populations of Coquerel's sifakas, tchi-fak playbacks elicited anti-terrestrial predator responses. More strikingly, Verreaux's sifakas exhibited anti-terrestrial predator responses after playbacks of growls in the population with a higher threat of predation by terrestrial predators, whereas Coquerel's sifakas in the raptor-dominated habitat seemed to associate growls with a threat by raptors; the 2 other populations of each species associated a mild disturbance with growls. We interpret this differential comprehension and usage of alarm calls as the result of social learning processes that caused changes in signal content in response to changes in the set of predators to which these populations have been exposed since they last shared a common ancestor. © 2010 The Author(s).

Stingl J.C.,University of Bonn | Bartels H.,University of Ulm | Viviani R.,University of Ulm | Lehmann M.L.,University of Bonn | Brockmoller J.,University of Gottingen
Pharmacology and Therapeutics | Year: 2014

UDP-glucuronosyltransferases (UGT) catalyze the biotransformation of many endobiotics and xenobiotics, and are coded by polymorphic genes. However, knowledge about the effects of these polymorphisms is rarely used for the individualization of drug therapy. Here, we present a quantitative systematic review of clinical studies on the impact of UGT variants on drug metabolism to clarify the potential for genotype-adjusted therapy recommendations. Data on UGT polymorphisms and dose-related pharmacokinetic parameters in man were retrieved by a systematic search in public databases. Mean estimates of pharmacokinetic parameters were extracted for each group of carriers of UGT variants to assess their effect size. Pooled estimates and relative confidence bounds were computed with a random-effects meta-analytic approach whenever multiple studies on the same variant, ethnic group, and substrate were available. Information was retrieved on 30 polymorphic metabolic pathways involving 10 UGT enzymes. For irinotecan and mycophenolic acid a wealth of data was available for assessing the impact of genetic polymorphisms on pharmacokinetics under different dosages, between ethnicities, under comedication, and under toxicity. Evidence for effects of potential clinical relevance exists for 19 drugs, but the data are not sufficient to assess effect size with the precision required to issue dose recommendations. In conclusion, compared to other drug metabolizing enzymes much less systematic research has been conducted on the polymorphisms of UGT enzymes. However, there is evidence of the existence of large monogenetic functional polymorphisms affecting pharmacokinetics and suggesting a potential use of UGT polymorphisms for the individualization of drug therapy. © 2013 Elsevier Inc.

Zahn J.,University of Gottingen
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2010

We study quantum electrodynamics on the noncommutative Minkowski space (NCQED) in the Yang-Feldman formalism. Local observables are defined by using covariant coordinates. We compute the two-point function of the interacting field strength to second order and find the infrared divergent terms already known from computations using the so-called modified Feynman rules. It is shown that these lead to nonlocal renormalization ambiguities. Also new nonlocal divergences stemming from the covariant coordinates are found. Furthermore, we study the supersymmetric extension of the model. For this, the supersymmetric generalization of the covariant coordinates is introduced. We find that the nonlocal divergences cancel. At the one-loop level, the only effect of noncommutativity is then a momentum-dependent field strength normalization. We interpret it as an acausal effect and show that its range is independent of the noncommutativity scale. © 2010 The American Physical Society.

Doenecke D.,University of Gottingen
Cell and Tissue Research | Year: 2014

This review focuses on the major protein moiety of chromosomes, i.e., the histone proteins, on the contribution of their posttranslational modification to structural and functional chromatin dynamics, on the acetylation and methylation of lysine residues, and on the phosphorylation of serine or threonine with respect to various steps during the cell cycle. © 2014 Springer-Verlag.

Kaatze U.,University of Gottingen
International Journal of Thermophysics | Year: 2014

Broadband dielectric spectra (1 MHz to 80 GHz) are reported for dimethyl sulfoxide–water mixtures in the complete composition range. The spectra are evaluated in order to yield information about the underlying relaxation time distribution, the principal relaxation time, and the static permittivity of the liquids. With a view of gaining insights into the structure and microdynamics of water in its different states of interaction, these parameters are compared to such for mixtures of water with other protic and aprotic dipolar liquids as well as with non-polar substances. Also used for information about structure fluctuations are ultrasonic spectra of the dimethyl sulfoxide–water system (0.2 MHz to 2.75 GHz). A notable result is the composition dependence of the principal dielectric relaxation time. In conformity with the wait-and-switch model, it increases at low DMSO content and thus reflects the decrement in the concentration of hydrogen-bonding sites. The decreasing relaxation time at high DMSO content is clearly a result of the reduced association due to the reduced concentration of hydrogen-donating sites. © 2014, Springer Science+Business Media New York.

Paulus W.,University of Gottingen
Neuropsychological Rehabilitation | Year: 2011

Weak transcranial direct current stimulation (tDCS) with a homogenous DC field at intensities of around 1 mA induces long-lasting changes in the brain. tDCS can be used to manipulate brain excitability via membrane polarisation: cathodal stimulation hyperpolarises, while anodal stimulation depolarises the resting membrane potential, whereby the induced after-effects depend on polarity, duration and intensity of the stimulation. A variety of other parameters influence tDCS effects; co-application of neuropharmacologically active drugs may most impressively prolong or even reverse stimulation effects. Transcranial alternating stimulation (tACS) and random noise stimulation (tRNS) are used to interfere with ongoing neuronal oscillations and also finally produce neuroplastic effects if applied with appropriate parameters. © 2011 Psychology Press.

Port M.,University of Gottingen
Biology letters | Year: 2013

Models of social conflict in animal societies generally assume that within-group conflict reduces the value of a communal resource. For many animals, however, the primary cost of conflict is increased mortality. We develop a simple inclusive fitness model of social conflict that takes this cost into account. We show that longevity substantially reduces the level of within-group conflict, which can lead to the evolution of peaceful animal societies if relatedness among group members is high. By contrast, peaceful outcomes are never possible in models where the primary cost of social conflict is resource depletion. Incorporating mortality costs into models of social conflict can explain why many animal societies are so remarkably peaceful despite great potential for conflict.

Polle A.,University of Gottingen | Chen S.,Beijing Forestry University
Plant, Cell and Environment | Year: 2015

Saline and sodic soils that cannot be used for agriculture occur worldwide. Cultivating stress-tolerant trees to obtain biomass from salinized areas has been suggested. Various tree species of economic importance for fruit, fibre and timber production exhibit high salinity tolerance. Little is known about the mechanisms enabling tree crops to cope with high salinity for extended periods. Here, the molecular, physiological and anatomical adjustments underlying salt tolerance in glycophytic and halophytic model tree species, such as Populus euphratica in terrestrial habitats, and mangrove species along coastlines are reviewed. Key mechanisms that have been identified as mediating salt tolerance are discussed at scales from the genetic to the morphological level, including leaf succulence and structural adjustments of wood anatomy. The genetic and transcriptomic bases for physiological salt acclimation are salt sensing and signalling networks that activate target genes; the target genes keep reactive oxygen species under control, maintain the ion balance and restore water status. Evolutionary adaptation includes gene duplication in these pathways. Strategies for and limitations to tree improvement, particularly transgenic approaches for increasing salt tolerance by transforming trees with single and multiple candidate genes, are discussed. © 2014 John Wiley & Sons Ltd.

Zemel A.,Fritz Haber Institute | Rehfeldt F.,University of Pennsylvania | Rehfeldt F.,University of Gottingen | Brown A.E.X.,University of Pennsylvania | And 2 more authors.
Nature Physics | Year: 2010

The shape and differentiated state of many cell types are highly sensitive to the rigidity of the microenvironment. The physical mechanisms involved, however, are unknown. Here, we present a theoretical model and experiments demonstrating that the alignment of stress fibres within stem cells is a non-monotonic function of matrix rigidity. We treat the cell as an active elastic inclusion in a surrounding matrix, allowing the actomyosin forces to polarize in response to elastic stresses developed in the cell. The theory correctly predicts the monotonic increase of the cellular forces with the matrix rigidity and the alignment of stress fibres parallel to the long axis of cells. We show that the anisotropy of this alignment depends non-monotonically on matrix rigidity and demonstrate it experimentally by quantifying the orientational distribution of stress fibres in stem cells. These findings offer physical insight into the sensitivity of stem-cell differentiation to tissue elasticity and, more generally, introduce a cell-type-specific parameter for actomyosin polarizability. © 2010 Macmillan Publishers Limited. All rights reserved.

Krone B.,University of Gottingen
Journal of Cancer Research and Clinical Oncology | Year: 2010

Introduction: A diverse range of human diseases, including allergy, asthma, autoimmune disease, cancer and chronic neurologic diseases, notably multiple sclerosis and endogenous depression, is becoming more prevalent in industrialized countries. It has been postulated that environmental factors associated with improved standards of hygiene play a leading role in this process since the immune system seems to need extrinsic challenges for its proper maturation. The inner world: An added dimension has now emerged-the impact on disease of the inner world, principally the numerous endogenous retroviruses (HERVs) within the human genome. Taking melanoma as an example, we propose a framework for understanding how a complex infectious and immunological background can induce or inhibit expression of a HERV-related disease process. The central role of a failure to induce or to maintain certain populations of self-specific CD8+ T-cells mediating immune surveillance, the expression of HERV-encoded peptides on affected cells and pathological mechanisms directly attributable to HERV proteins are discussed. Conclusions: The presented concepts explain events preceding the clinical manifestation of diseases by several years and provide a rationale for the use of currently available vaccines to protect against certain HERV-induced diseases, especially melanoma. Criteria for establishing the causal role of HERVs in a given disease are proposed. © 2010 The Author(s).

Hoyer-Fender S.,University of Gottingen
Seminars in Cell and Developmental Biology | Year: 2010

Centrioles and basal bodies are fascinating and mysterious organelles. They interconvert and seem to be crucial for a wide range of crucial cellular processes. However, intense research over the last years suggested that centrioles/basal bodies are essential mainly for the generation of cilia. Although a neglected organelle over a long time, interest in the primary cilia was recently rekindled by the notion that they are affected in a number of human diseases. Cilia formation is an intricate process that starts with the transformation of centrioles to basal bodies and their docking to the apical plasma membrane. Disturbance of basal body formation thus might cause ciliopathies. This review focuses on the formation of basal bodies in mammalian cells with an emphasis on basal bodies sprouting a primary cilium. © 2009 Elsevier Ltd. All rights reserved.

Martinez-Zarzoso I.,University of Gottingen | Martinez-Zarzoso I.,Jaume I University | Maruotti A.,Third University of Rome
Ecological Economics | Year: 2011

This paper analyzes the impact of urbanization on CO2 emissions in developing countries from 1975 to 2003. It contributes to the existing literature by examining the effect of urbanization, taking into account dynamics and the presence of heterogeneity in the sample of countries. The results show an inverted-U shaped relationship between urbanization and CO2 emissions. Indeed, the elasticity emission-urbanization is positive for low urbanization levels, which is in accordance with the higher environmental impact observed in less developed regions. Among our contributions is the estimation of a semi-parametric mixture model that allows for unknown distributional shapes and endogenously classifies countries into homogeneous groups. Three groups of countries are identified for which urbanization's impact differs considerably. For two of the groups, a threshold level is identified beyond which the emission-urbanization elasticity is negative and further increases in the urbanization rate do not contribute to higher emissions. However, for the third group only population and affluence, but not urbanization, contribute to explain emissions. The differential impact of urbanization on CO2 emissions should therefore be taken into account in future discussions of climate change policies. © 2011 Elsevier B.V.

Wrochna M.,University of Gottingen
Annales Henri Poincare | Year: 2012

We prove that the ground state for the Dirac equation on Minkowski space in static, smooth external potentials satisfies the Hadamard condition. We show that it follows from a condition on the support of the Fourier transform of the corresponding positive frequency solution. Using a Klein space formalism, we establish an analogous result in the Klein-Gordon case for a wide class of smooth potentials. Finally, we investigate overcritical potentials, i. e. which admit no ground states. It turns out, that numerous Hadamard states can be constructed by mimicking the construction of ground states, but this leads to a naturally distinguished one only under more restrictive assumptions on the potentials. © 2012 The Author(s).

Hager A.,Center for Sustainable Development | Dohrenbusch A.,University of Gottingen
Hydrological Processes | Year: 2011

Tropical cloud forests have received increasing attention because of their significance for freshwater supply. This study aimed to understand hydro-meteorological gradients in relation to spatial changes in forest structure in north-western Costa Rica. Seven climate stations (measuring rainfall, horizontal precipitation, throughfall, temperature and soil moisture) were installed along a 2·5 km transect between 1200 and 1500 m.a.s.l. on the Atlantic (windward) slope and the Pacific (leeward) slope of the Tilarán mountains. Forest structure was investigated on seven 10 × 50 m plots. Epiphytic vegetation was assessed on six trees at 1450 m and at 1200 m on the Pacific slope. Annual rainfall ranged from 3690 mm on the leeward slope to 6390 mm on the windward side. Horizontal precipitation was 3560 mm at the ridge, where it exceeded rainfall during the dry season, compared to 330 mm and 28 mm at the lowest windward and leeward plots, respectively. Throughfall remained below rainfall on the lower slopes but exceeded rainfall on the ridge. Soil water content ranged between 70% and 80% on the ridge top, where waterlogging occurred frequently. The studied forests were classified as lower montane rain forest, lower montane cloud forest and elfin cloud forest. The greatest canopy heights and basal areas occurred on the leeward slope between 1200 and 1450 m and at the lowest windward plot. Tree heights remained below 15 m on the ridge, where stilt roots occurred frequently. Near the ridge, epiphyte abundance and species richness were greater, compared to the lower leeward slope. These findings prove the importance of horizontal precipitation in the study area, confirm the important role of epiphytes as indicators for moisture gradients and elucidate the variability of forest structure under the given biophysical conditions. Copyright © 2010 John Wiley & Sons, Ltd.

Mani N.,University of Gottingen | Huettig F.,Max Planck Institute for Psycholinguistics | Huettig F.,Radboud University Nijmegen
Journal of Experimental Psychology: Human Perception and Performance | Year: 2012

Are there individual differences in children's prediction of upcoming linguistic input and what do these differences reflect? Using a variant of the preferential looking paradigm (Golinkoff, Hirsh-Pasek, Cauley, & Gordon, 1987), we found that, upon hearing a sentence like, "The boy eats a big cake," 2-year-olds fixate edible objects in a visual scene (a cake) soon after they hear the semantically constraining verb eats and prior to hearing the word cake. Importantly, children's prediction skills were significantly correlated with their productive vocabulary size-skilled producers (i.e., children with large production vocabularies) showed evidence of predicting upcoming linguistic input, while low producers did not. Furthermore, we found that children's prediction ability is tied specifically to their production skills and not to their comprehension skills. Prediction is really a piece of cake, but only for skilled producers. © 2012 American Psychological Association.

Hauser-Schaublin B.,University of Gottingen
Human Ecology | Year: 2011

The Batur Temple (Pura Ulun Danu Batur) in Kintamani is located at the geographic apex of a so-called ritual water hierarchy and has conventionally been described as a purely religious institution responsible for the coordination and distribution of the irrigation water. However, an analysis of historical palm leaf manuscripts reveals that the temple had a firm economic base with corresponding interests and that it was one of the most important land-owners in late pre-colonial Bali. The article therefore explores from a socio-political and economic perspective the implications of this form of temple landlordism and its combination with ritual water control, particularly for the peasants and the portion of their annual surplus that they were obliged to deliver to this temple. © 2011 The Author(s).

MacKintosh F.C.,VU University Amsterdam | Schmidt C.F.,University of Gottingen
Current Opinion in Cell Biology | Year: 2010

The materials cells are made of are strikingly different from man-made materials. Metabolism keeps cells out of equilibrium. Motor proteins and energy-consuming polymerization drive shape changes and motion. In contrast to macroscopic machines, though, there is no clear distinction between the force generators and the structural elements. Rather, the force-generating motor proteins are mixed with the elementary building blocks of cell structure on a molecular scale. The composite ensemble presents a new type of active material which is at the focus of intense current research. Simple model systems have been used successfully in exploring fundamental phenomena. Theoretical models are extending conventional soft matter approaches, and pioneering studies strive to analyze the complex nonequilibrium dynamics of living cells. © 2010 Elsevier Ltd. All rights reserved.

Al Ghazal P.,University of Gottingen | Dissemond J.,University of Duisburg - Essen
JDDG - Journal of the German Society of Dermatology | Year: 2015

Background: There are currently no therapeutic guidelines with respect to pyoderma gangrenosum (PG). Material and methods: In order to systematically record currently practiced therapeutic options for PG, a questionnaire was developed and sent to experts at various German dermatology departments. Results: Overall, 50 fully completed questionnaires were returned to us. On average, the diagnosis of PG is made 15 times per year. Of these patients, 11.1 % receive only topical therapy; 22.7 %, exclusively systemic therapy; and 66.2 %, both topical and systemic immunomodulatory therapy. Topically, the experts most commonly use class III (78 %) and class IV corticosteroids (88 %). All experts (100 %) reported the frequent use of systemic corticosteroids in the therapy of PG patients. Cyclosporine is used in 74 %, TNF-α inhibitors in 24 %, and azathioprine or mycophenolate mofetil each in 20 % of patients. Systemic agents such as dapsone (16 %), intravenous immunoglobulins (14 %), methotrexate (6 %), cyclophosphamide (4 %), tacrolimus (4 %), and rituximab (2 %), however, are given less frequently. Conclusions: Worldwide, no uniformly accepted standard is available for the treatment of patients with PG. In our survey among experts, treatment regimens currently used in Germany, and based on expert clinical experience, have now been recorded, analyzed, and benchmarked for the first time. © 2015 Deutsche Dermatologische Gesellschaft (DDG).

Goenner H.F.M.,University of Gottingen
Living Reviews in Relativity | Year: 2014

The present review intends to provide an overall picture of the research concerning classical unified field theory, worldwide, in the decades between the mid-1930 and mid-1960. Main themes are the conceptual and methodical development of the field, the interaction among the scientists working in it, their opinions and interpretations. Next to the most prominent players, A. Einstein and E. Schr̈odinger, V. Hlavat́y and the French groups around A. Lichnerowicz, M.-A. Tonnelat, and Y. Thiry are presented. It is shown that they have given contributions of comparable importance. The review also includes a few sections on the fringes of the central topic like Born-Infeld electromagnetic theory or scalar-tensor theory. Some comments on the structure and organization of research-groups are also made.

Krahmer F.,University of Gottingen | Ward R.,University of Texas at Austin
IEEE Transactions on Image Processing | Year: 2014

In many signal processing applications, one wishes to acquire images that are sparse in transform domains such as spatial finite differences or wavelets using frequency domain samples. For such applications, overwhelming empirical evidence suggests that superior image reconstruction can be obtained through variable density sampling strategies that concentrate on lower frequencies. The wavelet and Fourier transform domains are not incoherent because low-order wavelets and low-order frequencies are correlated, so compressive sensing theory does not immediately imply sampling strategies and reconstruction guarantees. In this paper, we turn to a more refined notion of coherence - the so-called local coherence - measuring for each sensing vector separately how correlated it is to the sparsity basis. For Fourier measurements and Haar wavelet sparsity, the local coherence can be controlled and bounded explicitly, so for matrices comprised of frequencies sampled from a suitable inverse square power-law density, we can prove the restricted isometry property with near-optimal embedding dimensions. Consequently, the variable-density sampling strategy we provide allows for image reconstructions that are stable to sparsity defects and robust to measurement noise. Our results cover both reconstruction by $\ell1-minimization and total variation minimization. The local coherence framework developed in this paper should be of independent interest, as it implies that for optimal sparse recovery results, it suffices to have bounded average coherence from sensing basis to sparsity basis - as opposed to bounded maximal coherence - as long as the sampling strategy is adapted accordingly. © 1992-2012 IEEE.

Boehncke W.-H.,University of Geneva | Schon M.P.,University of Gottingen
The Lancet | Year: 2015

Psoriasis is an immune-mediated, genetic disease manifesting in the skin or joints or both. A diverse team of clinicians with a range of expertise is often needed to treat the disease. Psoriasis provides many challenges including high prevalence, chronicity, disfiguration, disability, and associated comorbidity. Understanding the role of immune function in psoriasis and the interplay between the innate and adaptive immune system has helped to manage this complex disease, which affects patients far beyond the skin. In this Seminar, we highlight the clinical diversity of psoriasis and associated comorbid diseases. We describe recent developments in psoriasis epidemiology, pathogenesis, and genetics to better understand present trends in psoriasis management. Our key objective is to raise awareness of the complexity of this multifaceted disease, the potential of state-of-the-art therapeutic approaches, and the need for early diagnosis and comprehensive management of patients with psoriasis. © 2015 Elsevier Ltd.

Kirchheim R.,University of Gottingen
Scripta Materialia | Year: 2010

Models explaining hydrogen embrittlement as caused by enhanced local plasticity are discussed in the light of a novel concept describing solute-defect interaction in a thermodynamic framework. Solute atoms segregating at defects with an excess Γ are called defactants because they lower the defect formation energy of defects γ, analagous to the action of surfactants with surfaces. The corresponding decrease is given by dγ = -Γdμ, where μ is the chemical potential of the defactant. This equation is applied to recent nanoindentation results, and reveals a lower energy barrier for the generation of dislocation loops in the presence of hydrogen. © 2009 Acta Materialia Inc.

Wiese L.,University of Gottingen
Journal of Cloud Computing | Year: 2014

One feature of cloud storage systems is data fragmentation (or sharding) so that data can be distributed over multiple servers and subqueries can be run in parallel on the fragments. On the other hand, flexible query answering can enable a database system to find related information for a user whose original query cannot be answered exactly. Query generalization is a way to implement flexible query answering on the syntax level. In this paper we study a clustering-based fragmentation for the generalization operator Anti-Instantiation with which related information can be found in distributed data. We use a standard clustering algorithm to derive a semantic fragmentation of data in the database. The database system uses the derived fragments to support an intelligent flexible query answering mechanism that avoids overgeneralization but supports data replication in a distributed database system. We show that the data replication problem can be expressed as a special Bin Packing Problem and can hence be solved by an off-the shelf solver for integer linear programs. We present a prototype system that makes use of a medical taxonomy to determine similarities between medical expressions. © 2014, Wiese; licensee Springer.

Riek A.,University of Gottingen | Riek A.,University of New England of Australia | Geiser F.,University of New England of Australia
Biological Reviews | Year: 2013

A large number of analyses have examined how basal metabolic rate (BMR) is affected by body mass in mammals. By contrast, the critical ambient temperatures that define the thermo-neutral zone (TNZ), in which BMR is measured, have received much less attention. We provide the first phylogenetic analyses on scaling of lower and upper critical temperatures and the breadth of the TNZ in 204 mammal species from diverse orders. The phylogenetic signal of thermal variables was strong for all variables analysed. Most allometric relationships between thermal variables and body mass were significant and regressions using phylogenetic analyses fitted the data better than conventional regressions. Allometric exponents for all mammals were 0.19 for the lower critical temperature (expressed as body temperature - lower critical temperature), -0.027 for the upper critical temperature, and 0.17 for the breadth of TNZ. The small exponents for the breadth of the TNZ compared to the large exponents for BMR suggest that BMR per se affects the influence of body mass on TNZ only marginally. However, the breadth of the TNZ is also related to the apparent thermal conductance and it is therefore possible that BMR at different body masses is a function of both the heat exchange in the TNZ and that encountered below and above the TNZ to permit effective homeothermic thermoregulation. © 2013 Cambridge Philosophical Society.

Mehta V.P.,University of Gottingen | Van Der Eycken E.V.,Catholic University of Leuven
Chemical Society Reviews | Year: 2011

Among the fundamental transformations in the field of synthetic organic chemistry, transition-metal-catalyzed reactions provide some of the most attractive methodologies for the formation of C-C and C-heteroatom bonds. As a result, the application of these reactions has increased tremendously during the past decades and cross-coupling reactions became a standard tool for synthetic organic chemists. Furthermore, a tremendous upsurge in the development of new catalysts and ligands, as well as an increased understanding of the mechanisms, has contributed substantially to recent advances in the field. Traditionally, organic reactions are carried out by conductive heating with an external heat source (for example, an oil bath). However, the application of microwave irradiation is a steadily gaining field as an alternative heating mode since its dawn at the end of the last century. This tutorial review focuses on some of the recent developments in the field of cross-coupling reactions assisted by microwave irradiation. © 2011 The Royal Society of Chemistry.

Speck T.,Heinrich Heine University Dusseldorf | Vink R.L.C.,University of Gottingen
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2012

Theoretical models describing specific adhesion of membranes predict (for certain parameters) a macroscopic phase separation of bonds into adhesion domains. We show that this behavior is fundamentally altered if the membrane is pinned randomly due to, e.g., proteins that anchor the membrane to the cytoskeleton. Perturbations which locally restrict membrane height fluctuations induce quenched disorder of the random-field type. This rigorously prevents the formation of macroscopic adhesion domains following the Imry-Ma argument. Our prediction of random-field disorder follows from analytical calculations and is strikingly confirmed in large-scale Monte Carlo simulations. These simulations are based on an efficient composite Monte Carlo move, whereby membrane height and bond degrees of freedom are updated simultaneously in a single move. The application of this move should prove rewarding for other systems also. © 2012 American Physical Society.

de Hoz L.,Max Planck Institute for Experimental Medicine | Simons M.,Max Planck Institute for Experimental Medicine | Simons M.,University of Gottingen
BioEssays | Year: 2015

Myelin is required for efficient nerve conduction, but not all axons are myelinated to the same extent. Here we review recent studies that have revealed distinct myelination patterns of different axonal paths, suggesting that myelination is not an all or none phenomenon and that its presence is finely regulated in central nervous system networks. Whereas powerful reductionist biology has led to important knowledge of how oligodendrocytes function by themselves, little is known about their role in neuronal networks. We still do not understand how oligodendrocytes integrate information from neurons to adapt their function to the need of the system. An intricate cross talk between neurons and glia is likely to exist and to determine how neuronal circuits operate as a whole. Dissecting these mechanisms by using integrative systems biology approaches is one of the major challenges ahead. © 2015 WILEY Periodicals, Inc.

Thiel V.,University of Gottingen | Sjovall P.,SP Technical Research Institute of Sweden
Annual Review of Earth and Planetary Sciences | Year: 2011

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a technique designed to analyze the composition and spatial distribution of molecules and chemical structures on surfaces. These capabilities have generated much interest in its use in geobiology, in particular for the characterization of organic biomarkers (molecular biosignatures) at the microscopic level. We here discuss the strengths, weaknesses, and potential of ToF-SIMS for biomarker analyses with a focus on applications in geobiology, including biogeochemistry, organic geochemistry, geomicrobiology, and paleobiology. After describing the analytical principles of ToF-SIMS, we discuss issues of biomarker spectral formation and interpretation. Then, key applications of ToF-SIMS to soft (microbial matter, cells), hard (microbial mineral precipitates), and liquid (petroleum) samples relevant in geobiology are reviewed. Finally, we examine the potential of ToF-SIMS in biomarker research and the current limitations and obstacles for which further development would be beneficial to the field. Copyright © 2011 by Annual Reviews. All rights reserved.

Kues U.,University of Gottingen
Current Opinion in Biotechnology | Year: 2015

Fungal ligninolytic enzymes have broad biotechnological applications. Particularly laccases and certain fungal class II peroxidases from white-rot basidiomycetes are considered in degradation of persistent organic pollutants. Promising processes with reusable immobilized laccases in special reactors have been developed up to pilot scale for degradation of pollutants in water. Bioremediation of chemically complex soils with their large indigenous microbial communities is more difficult. Living fungi and their enzymes are employed. Bioaugmentation, introduction of for example white-rots for enzyme production into a polluted soil, and biostimulation of suitable resident organisms by nutritional manipulations are strategies in degradation of pollutants in soil. Bioaugmentation has been successfully implemented on small scale for soils in biobeds and for specific materials such as olive mill wastes. © 2015 Elsevier Ltd.

Noubactep C.,University of Gottingen | Noubactep C.,Kultur und Nachhaltige Entwicklung CDD e.V.
Water Research | Year: 2015

This article critically evaluates recent review articles on using metallic iron (Fe0) for environmental remediation in order to provide insight for more efficient Fe0-based systems. The presentation is limited to peer-reviewed articles published during 2014 and 2015, excluding own contributions, dealing mostly with granular Fe0. A literature search was conducted up to June 15th 2015 using Science Direct, SCOPUS, Springer and Web of Science databases. The search yielded eight articles that met the final inclusion criteria. The evaluation clearly shows that seven articles provide a narrative description of processes occurring in the Fe0/H20 system according to the concept that Fe0 is a reducing agent. Only one article clearly follows a different path, presenting Fe0 as a generator of adsorbing (hydroxides, oxides) and reducing (FeII, H/H2) agents. The apparent discrepancies between the two schools are identified and extensively discussed based on the chemistry of the Fe0/H20 system. The results of this evaluation indicate clearly that research on 'Fe0 for environmental remediation' is in its infancy. Despite the current paucity of reliable data for the design of efficient Fe0-based systems, this review demonstrates that sensible progress could be achieved within a short period of time, specific recommendations to help guide future research are suggested. © 2015 Elsevier Ltd.

Grimmsmann T.,Review-Board | Himmel W.,University of Gottingen
European Journal of Clinical Pharmacology | Year: 2014

Purpose: To study drug persistence for antihypertensive treatment considering typical patient behaviour including extended drug holidays or irregular repeat prescriptions. Methods: We used prescription data from a German statutory health insurance to follow up patients for 4 years. Medication persistence was defined as the continued use of a specific drug class, therapy persistence as the continued use of any antihypertensive drug. We applied 2 different interval criteria within which a repeat prescription had to be issued: 180 and 360 days. Results: A total of 9,513 patients started an antihypertensive therapy between 2006 and 2008. Applying the 180-day (360-day) interval criterion, 28 % (66 %) of the patients starting therapy with a beta-blocker were still medication-persistent after 4 years. The rates were similar for angiotensin-II receptor blockers (ARBs; 30 % and 69 % respectively) or angiotensin-converting enzyme (ACE) inhibitors (28 % and 61 % respectively). Looking at therapy persistence, these rates were 44 % (79 %) when an ACE inhibitor was the initial drug, 46 % (82 %) for ARBs. On average, even of those who were defined as therapeutically persistent with the 360 days criterion, half received a repeat prescription within 96 days, three quarters within 131 days - with a median supply of 1.2 units per day and 1.25 defined daily doses. Conclusion: By applying more patient-orientated criteria, we found that many patients were therapy-persistent and received a prescription at the appropriate time. Therapy persistence was nearly independent of the initial agent; thus, drug persistence may not be an argument in favour of choosing a certain drug as a first-line option. © 2013 Springer-Verlag Berlin Heidelberg.

Fuhrmans M.,Zernike Institute for Advanced Materials | Fuhrmans M.,University of Gottingen | Marrink S.J.,Zernike Institute for Advanced Materials
Journal of the American Chemical Society | Year: 2012

Fusion peptides are moderately hydrophobic segments of viral and nonviral membrane fusion proteins that enable these proteins to fuse two closely apposed biological membranes. In vitro assays furthermore show that even isolated fusion peptides alone can support membrane fusion in model systems. In addition, the fusion peptides have a distinct effect on the phase diagram of lipid mixtures. Here, we present molecular dynamics simulations investigating the effect of a particular fusion peptide, the influenza hemagglutinin fusion peptide and some of its mutants, on the lipid phase diagram. We detect a systematic shift toward phases with more positive mean curvature in the presence of the peptides, as well as an occurrence of bicontinuous cubic phases, which indicates a stabilization of Gaussian curvature. The wild-type fusion peptide has a stronger effect on the phase behavior as compared to the mutants, which we relate to its boomerang shape. Our results point to a different role of fusion peptides than hitherto assumed, the stabilization of pores rather than stalks along the fusion pathway. © 2011 American Chemical Society.

Tutz G.,Ludwig Maximilians University of Munich | Gertheiss J.,University of Gottingen
Psychometrika | Year: 2014

Rating scales as predictors in regression models are typically treated as metrically scaled variables or, alternatively, are coded in dummy variables. The first approach implies a scale level that is not justified, the latter approach results in a large number of parameters to be estimated. Therefore, when rating scales are dummy-coded, applications are often restricted to the use of a few predictors. The penalization approach advocated here takes the scale level serious by using only the ordering of categories but is shown to work in the high dimensional case. We consider the proper modeling of rating scales as predictors and selection procedures by using penalization methods that are tailored to ordinal predictors. In addition to the selection of predictors, the clustering of categories is investigated. Existing methodology is extended to the wider class of generalized linear models. Moreover, higher order differences that allow shrinkage towards a polynomial as well as monotonicity constraints and alternative penalties are introduced. The proposed penalization approaches are illustrated by use of the Motivational States Questionnaire. © 2013, The Psychometric Society.

Gruene T.,University of Gottingen
Acta Crystallographica Section D: Biological Crystallography | Year: 2013

Model building starting from, for example, a molecular-replacement solution with low sequence similarity introduces model bias, which can be difficult to detect, especially at low resolution. The program mrtailor removes low-similarity regions from a template PDB file according to sequence similarity between the target sequence and the template sequence and maps the target sequence onto the PDB file. The modified PDB file can be used to generate external restraints for low-resolution refinement with reduced model bias and can be used as a starting point for model building and refinement. The program can call ProSMART [Nicholls et al. (2012), Acta Cryst. D68, 404-417] directly in order to create external restraints suitable for REFMAC5 [Murshudov et al. (2011), Acta Cryst. D67, 355-367]. Both a command-line version and a GUI exist. © 2013 International Union of Crystallography Printed in Singapore-all rights reserved.

Thorn A.,University of Cambridge | Sheldrick G.M.,University of Gottingen
Acta Crystallographica Section D: Biological Crystallography | Year: 2013

Although the program SHELXE was originally intended for the experimental phasing of macromolecules, it can also prove useful for expanding a small protein fragment to an almost complete polyalanine trace of the structure, given a favourable combination of native data resolution (better than about 2.1 Å) and solvent content. A correlation coefficient (CC) of more than 25% between the native structure factors and those calculated from the polyalanine trace appears to be a reliable indicator of success and has already been exploited in a number of pipelines. Here, a more detailed account of this usage of SHELXE for molecular-replacement solutions is given.

Heyl M.,Ludwig Maximilians University of Munich | Heyl M.,TU Dresden | Polkovnikov A.,Boston University | Kehrein S.,University of Gottingen
Physical Review Letters | Year: 2013

A phase transition indicates a sudden change in the properties of a large system. For temperature-driven phase transitions this is related to nonanalytic behavior of the free energy density at the critical temperature: The knowledge of the free energy density in one phase is insufficient to predict the properties of the other phase. In this Letter we show that a close analogue of this behavior can occur in the real time evolution of quantum systems, namely nonanalytic behavior at a critical time. We denote such behavior a dynamical phase transition and explore its properties in the transverse-field Ising model. Specifically, we show that the equilibrium quantum phase transition and the dynamical phase transition in this model are intimately related. © 2013 American Physical Society.

Kues U.,University of Gottingen | Martin F.,CNRS Trees/Micro-organism Interactions
Fungal Genetics and Biology | Year: 2011

The genome of the ectomycorrhizal ascomycete Tuber melanosporum has recently been published and this has given researchers unique opportunities to learn more about the biology of this precious edible fungus. The epigeous ascomycete lives in Mediterranean countries in symbiotic interaction with roots of broad-leaf trees such as oaks and hazel. A most important new finding was the single mating type locus in the genome that occurs with two alleles in natural populations. The life cycle is now confirmed to be heterothallic and the species is outcrossing. Unlike sexual development in the soil, mycorrhization of the roots by homokaryotic haploid mycelia is mating-type-independent. Gene regulation during mycorrhization and fruiting and environmental influences on it is now genome-wide addressed. Genome profiling for functions in specific metabolic pathways is undertaken. Insights in most enthralling features of tubers such as on odor formation are thus gained. © 2011 Elsevier Inc.

Staron A.,Ludwig Maximilians University of Munich | Finkeisen D.E.,University of Gottingen | Mascher T.,Ludwig Maximilians University of Munich
Antimicrobial Agents and Chemotherapy | Year: 2011

Peptide antibiotics are produced by a wide range of microorganisms. Most of them target the cell envelope, often by inhibiting cell wall synthesis. One of the resistance mechanisms against antimicrobial peptides is a detoxification module consisting of a two-component system and an ABC transporter. Upon the detection of such a compound, the two-component system induces the expression of the ABC transporter, which in turn removes the antibiotic from its site of action, mediating the resistance of the cell. Three such peptide antibiotic-sensing and detoxification modules are present in Bacillus subtilis. Here we show that each of these modules responds to a number of peptides and confers resistance against them. BceRS-BceAB (BceRS-AB) responds to bacitracin, plectasin, mersacidin, and actagardine. YxdJK-LM is induced by a cationic antimicrobial peptide, LL-37. The PsdRS-AB (formerly YvcPQ-RS) system responds primarily to lipid II-binding lantibiotics such as nisin and gallidermin. We characterized the psdRS-AB operon and defined the regulatory sequences within the P psdA promoter. Mutation analysis demonstrated that P psdA expression is fully PsdR dependent. The features of both the P bceA and P psdA promoters make them promising candidates as novel whole-cell biosensors that can easily be adjusted for high-throughput screening. Copyright © 2011, American Society for Microbiology. All Rights Reserved.

Antonin W.,Friedrich Miescher Laboratory of the Max Planck Society | Neumann H.,University of Gottingen
Current Opinion in Cell Biology | Year: 2016

During eukaryotic cell division, nuclear chromatin undergoes marked changes with respect to shape and degree of compaction. Although already significantly compacted during interphase, upon entry into mitosis chromatin further condenses and individualizes to discrete chromosomes that are captured and moved independently by the mitotic spindle apparatus. Once segregated by the spindle, chromatin decondenses to re-establish its interphase structure competent for DNA replication and transcription. Although cytologically described a long time ago, the underlying molecular mechanisms of mitotic chromatin condensation and decondensation are still ill-defined. Here we summarize our current knowledge of mitotic chromatin restructuring and recent progress in the field. © 2016 The Authors.

Uncomplicated urinary tract infections (UTI) are usually treated with antibiotics as recommended by primary care guidelines. Antibiotic treatment supports clinical cure in individual patients but also leads to emerging resistance rates in the population. We designed a comparative effectiveness study to investigate whether the use of antibiotics for uncomplicated UTI could be reduced by initial treatment with ibuprofen, reserving antibiotic treatment to patients who return due to ongoing or recurrent symptoms. This is a randomized-controlled, double-blind, double dummy multicentre trial assessing the comparative effectiveness of immediate vs. conditional antibiotic therapy in uncomplicated UTI. Women > 18 and < 65 years, presenting at general practices with at least one of the typical symptoms dysuria or frequency/urgency of micturition, will be screened and enrolled into the trial. During an 18- months recruitment period, a total of 494 patients will have to be recruited in 45 general practices in Lower Saxony. Participating patients receive either immediate antibiotic therapy with fosfomycin-trometamol 1x3g or initial symptomatic treatment with ibuprofen 3x400mg for 3 days. The ibuprofen group will be provided with antibiotic therapy only if needed, i.e. for persistent or worsening symptoms. For a combined primary endpoint, we choose the number of all antibiotic prescriptions regardless of the medical indication day 0-28 and the "disease burden", defined as a weighted sum of the daily total symptom scores from day 0 to day 7. The study is considered positive if superiority of conditional antibiotic treatment with respect to the first primary endpoint and non-inferiority of conditional antibiotic treatment with respect to the second primary endpoint is proven. This study aims at investigating whether the use of antibiotics for uncomplicated UTI could be reduced by initial treatment with ibuprofen. The comparative effectiveness design was chosen to prove the effectiveness of two therapeutic strategies instead of the pure drug efficacy.

Stingl J.C.,University of Ulm | Brockmoller J.,University of Gottingen
Clinical Pharmacology and Therapeutics | Year: 2011

The growing interest in incorporating pharmacogenetics (PGx) into drug development and clinical practice raises several questions: which study designs best reveal relevant pharmacogenetic biomarkers, best clarify specific hypotheses in PGx, and result in the largest gain of clinical evidence in this field In this review, we present and compare a variety of PGx-related study designs. The type and quality of evidence gained by each category of study design is evaluated, and an appropriate timeline for the integration of pharmacogenetic studies into drug development is proposed. A summary of the pros and cons of the different study designs might help investigators decide how best to incorporate PGx into drug research. Using different scenarios to explain how genetic polymorphisms influence drug action, we illustrate how this knowledge can be translated into individualized drug choices, individualized dosage determination based on pharmacogenetic diagnostics, and other types of monitoring in order to make drug therapies safer and more effective. © 2011 american Society for Clinical Pharmacology and Therapeutics.

Maier L.S.,University of Gottingen
Advances in Experimental Medicine and Biology | Year: 2012

Aim of this review is to give an overview and discuss recent findings on the role of Ca 2+/calmodulin-dependent protein kinase II (CaMKII) in the heart. Special attention is drawn to excitation-contraction coupling (ECC) and excitation-transcription coupling (ETC). Because CaMKII expression and activity are increased in cardiac hypertrophy, heart failure, and during arrhythmias both in animal models as well as in the human heart a clinical significance of CaMKII is implied. © 2012 Springer Science+Business Media B.V.

Jonsson T.,University of Gottingen
Fly | Year: 2011

Male Drosophila fruit flies acquire and defend territories in order to attract females for reproduction. Both, male-directed agonistic behavior and female-directed courtship consist of series of recurrent stereotypical components. Various studies demonstrated the importance of species-specific sound patterns generated by wing vibration as being critical for male courtship success. In this study we analyzed the patterns and importance of sound signals generated during agonistic interactions of male Drosophila melanogaster. In contrast to acoustic courtship signals that consist of sine and pulse patterns and are generated by one extended wing, agonistic signals lack sine-like components and are generally produced by simultaneous movements of both wings. Though intra-pulse oscillation frequencies (carrier frequency) are identical, inter-pulse intervals are twice as long and more variable in aggression signals than in courtship songs, where their precise temporal pattern serves species recognition. Acoustic signals accompany male agonistic interactions over their entire course but occur particularly often after tapping behavior which is a major way to identify the gender of the interaction partner. Since similar wing movements may either be silent or generate sound and wing movements with sound have a greater impact on the subsequent behavior of a receiver, sound producing wing movements seem to be generated intentionally to serve as a specific signal during fruit fly agonistic encounters.

Kuzyakov Y.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research | Kuzyakov Y.,University of Gottingen | Xu X.,CAS Beijing Institute of Geographic Sciences and Nature Resources Research
New Phytologist | Year: 2013

Demand of all living organisms on the same nutrients forms the basis for interspecific competition between plants and microorganisms in soils. This competition is especially strong in the rhizosphere. To evaluate competitive and mutualistic interactions between plants and microorganisms and to analyse ecological consequences of these interactions, we analysed 424 data pairs from 41 15N-labelling studies that investigated 15N redistribution between roots and microorganisms. Calculated Michaelis-Menten kinetics based on Km (Michaelis constant) and Vmax (maximum uptake capacity) values from 77 studies on the uptake of nitrate, ammonia, and amino acids by roots and microorganisms clearly showed that, shortly after nitrogen (N) mobilization from soil organic matter and litter, microorganisms take up most N. Lower Km values of microorganisms suggest that they are especially efficient at low N concentrations, but can also acquire more N at higher N concentrations (Vmax) compared with roots. Because of the unidirectional flow of nutrients from soil to roots, plants are the winners for N acquisition in the long run. Therefore, despite strong competition between roots and microorganisms for N, a temporal niche differentiation reflecting their generation times leads to mutualistic relationships in the rhizosphere. This temporal niche differentiation is highly relevant ecologically because it: protects ecosystems from N losses by leaching during periods of slow or no root uptake; continuously provides roots with available N according to plant demand; and contributes to the evolutionary development of mutualistic interactions between roots and microorganisms. © 2013 New Phytologist Trust.

Whitehead S.R.,University of Colorado at Boulder | Poveda K.,University of Gottingen | Poveda K.,Cornell University
Journal of Ecology | Year: 2011

1.Herbivore attack can induce dramatic changes in plant chemical defences. These responses protect plants against future herbivory, but can also have important physiological and ecological costs. Ecological costs of defence have received recent theoretical attention; however, many proposed costs have not yet been demonstrated empirically. In particular, field data are lacking as to whether induced responses in leaves can lead to correlated changes in fruit palatability that reduce fruit removal by mutualist seed dispersers. 2.Using the tropical shrub, Hamelia patens (Rubiaceae), we examined changes in fruit removal, palatability and maturation time following various treatments to the subtending leaves, including herbivory, mechanical damage and/or application of methyl jasmonate (MeJA). 3.Fewer fruits were removed from herbivory- and MeJA-treated branches than from controls, and results from three bioassays with ants and fungi suggested that this response was mediated by changes in fruit palatability. In addition, fruits from MeJA-treated branches matured more quickly than those from control branches. 4.Synthesis. Taken together, our results provide novel evidence that induced responses to herbivory can affect fruit-frugivore interactions through two mechanisms: changes in fruit palatability and changes in fruit development time. This highlights the importance of physiological linkages between leaf and fruit traits in determining the overall costs of plant defence and the fitness outcomes of multispecies interactions. © 2011 The Authors. Journal of Ecology © 2011 British Ecological Society.