Georg August University Go Ttingen
Georg August University Go Ttingen
Rodri guez-Soalleiro R.,University of Santiago de Compostela |
Pe rez-Cruzado C.,Georg August University Go ttingen
Biomass and Bioenergy | Year: 2014
A Reference Diagram (RD) was constructed for first rotations of the Euroamerican poplar 'I-214' grown as short rotation coppice (SRC). Data from 144 plots, established in eleven sites in Mediterranean environments, were used to develop the model. The density at establishment of the plantations ranged between 6666 and 33,333 stools ha-1, covering the usual densities ranges used in short rotation forestry (SRF). The RD was based on a density-independent mortality model that relates the density of living stools to the average height of dominant shoot and the initial plantation density, and it includes a system of two simultaneously fitted equations relating a) quadratic mean basal diameter of dominant shoots to the average height of dominant shoot and the final density, and b) total above-ground woody dry biomass to quadratic mean basal diameter and final density. The isolines in the RD represented mortality, quadratic mean basal diameter of dominant shoots and total above-ground woody dry biomass at the end of a first rotation of three years. The final yield in terms of biomass ranged from 1 to 85 Mg dm ha-1. The RD enables rapid and straightforward comparison of different situations, both at planting and at harvesting, and is a useful tool, based on a wide range of empirical data, for management and decision making regarding short rotation poplar crops. © 2014 Elsevier Ltd.
Handa I.T.,CNRS Center of Evolutionary and Functional Ecology |
Handa I.T.,University of Québec |
Aerts R.,VU University Amsterdam |
Berendse F.,Wageningen University |
And 20 more authors.
Nature | Year: 2014
The decomposition of dead organic matter is a major determinant of carbon and nutrient cycling in ecosystems, and of carbon fluxes between the biosphere and the atmosphere. Decomposition is driven by a vast diversity of organisms that are structured in complex food webs. Identifying the mechanisms underlying the effects of biodiversity on decomposition is critical given the rapid loss of species worldwide and the effects of this loss on human well-being. Yet despite comprehensive syntheses of studies on how biodiversity affects litter decomposition, key questions remain, including when, where and how biodiversity has a role and whether general patterns and mechanisms occur across ecosystems and different functional types of organism. Here, in field experiments across five terrestrial and aquatic locations, ranging from the subarctic to the tropics, we show that reducing the functional diversity of decomposer organisms and plant litter types slowed the cycling of litter carbon and nitrogen. Moreover, we found evidence of nitrogen transfer from the litter of nitrogen-fixing plants to that of rapidly decomposing plants, but not between other plant functional types, highlighting that specific interactions in litter mixtures control carbon and nitrogen cycling during decomposition. The emergence of this general mechanism and the coherence of patterns across contrasting terrestrial and aquatic ecosystems suggest that biodiversity loss has consistent consequences for litter decomposition and the cycling of major elements on broad spatial scales. © 2014 Macmillan Publishers Limited.
Kumar J.,Tata Institute of Fundamental Research |
Choudhary B.C.,Tata Institute of Fundamental Research |
Metpally R.,Tata Institute of Fundamental Research |
Metpally R.,University of Iowa |
And 6 more authors.
PLoS Genetics | Year: 2010
UNC-104/KIF1A is a Kinesin-3 motor that transports synaptic vesicles from the cell body towards the synapse by binding to PI(4,5)P2 through its PH domain. The fate of the motor upon reaching the synapse is not known. We found that wild-type UNC-104 is degraded at synaptic regions through the ubiquitin pathway and is not retrogradely transported back to the cell body. As a possible means to regulate the motor, we tested the effect of cargo binding on UNC-104 levels. The unc-104(e1265) allele carries a point mutation (D1497N) in the PI(4,5)P2 binding pocket of the PH domain, resulting in greatly reduced preferential binding to PI(4,5)P2 in vitro and presence of very few motors on pre-synaptic vesicles in vivo. unc-104(e1265) animals have poor locomotion irrespective of in vivo PI(4,5)P2 levels due to reduced anterograde transport. Moreover, they show highly reduced levels of UNC-104 in vivo. To confirm that loss of cargo binding specificity reduces motor levels, we isolated two intragenic suppressors with compensatory mutations within the PH domain. These show partial restoration of in vitro preferential PI(4,5)P2 binding and presence of more motors on pre-synaptic vesicles in vivo. These animals show improved locomotion dependent on in vivo PI(4,5)P2 levels, increased anterograde transport, and partial restoration of UNC-104 protein levels in vivo. For further proof, we mutated a conserved residue in one suppressor background. The PH domain in this triple mutant lacked in vitro PI(4,5)P2 binding specificity, and the animals again showed locomotory defects and reduced motor levels. All allelic variants show increased UNC-104 levels upon blocking the ubiquitin pathway. These data show that inability to bind cargo can target motors for degradation. In view of the observed degradation of the motor in synaptic regions, this further suggests that UNC-104 may get degraded at synapses upon release of cargo. © 2010 Kumar et al.
Bechdolf A.,University of Cologne |
Muller H.,University of Cologne |
Stutzer H.,University of Cologne |
Wagner M.,University of Bonn |
And 15 more authors.
Schizophrenia Bulletin | Year: 2011
Antipsychotics, cognitive behavioral therapy (CBT), and omega-3-fatty acids have been found superior to control conditions as regards prevention of psychosis in people at-risk of first-episode psychosis. However, no large-scale trial evaluating the differential efficacy of CBT and antipsychotics has been performed yet. In PREVENT, we evaluate CBT, aripiprazole, and clinical management (CM) as well as placebo and CM for the prevention of psychosis in a randomized, double-blind, placebo-controlled trial with regard to the antipsychotic intervention and a randomized controlled trial with regard to the CBT intervention with blinded ratings. The hypotheses are first that CBT and aripiprazole and CM are superior to placebo and CM and second that CBT is not inferior to aripiprazole and CM combined. The primary outcome is transition to psychosis. By November 2010, 156 patients were recruited into the trial. The subjects were substantially functionally compromised (Social and Occupational Functioning Assessment Scale mean score 52.5) and 78.3% presented with a Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition axis I comorbid diagnosis. Prior to randomization, 51.5% of the participants preferred to be randomized into the CBT arm, whereas only 12.9% preferred pharmacological treatment. First, assessments of audiotaped treatment sessions confirmed the application of CBT-specific skills in the CBT condition and the absence of those in CM. The overall quality rating of the CBT techniques applied in the CBT condition was good. When the final results of the trial are available, PREVENT will substantially expand the current limited evidence base for best clinical practice in people at-risk (prodromal) of first-episode psychosis. © 2011 The Author.
Van Gelder T.,Erasmus Medical Center |
Silva H.T.,Hospital Do Rim e Hipertensao UNIFESP |
De Fijter H.,Leiden University |
Budde K.,Charité - Medical University of Berlin |
And 4 more authors.
Therapeutic Drug Monitoring | Year: 2011
Introduction: Mycophenolic acid (MPA) plasma concentrations are highly variable on standard-dose mycophenolate mofetil therapy. At creatinine clearances below 25 mL/min, MPA clearance increases as a result of a higher nonprotein-bound fraction. Patients with delayed graft function (DGF) after renal transplantation are exposed to low total MPA concentrations, when risk of rejection is highest. This study investigated the influence of DGF on MPA exposure and on clinical outcome. Methods: Adult renal transplantation patients treated with mycophenolate mofetil, corticosteroids, and either microemulsified cyclosporine (n = 459) or tacrolimus (n = 371) participated in a randomized controlled trial (the Fixed-Dose Concentration-Controlled [FDCC] Study). Abbreviated MPA areas under the curve (AUCs) were obtained on Day 3, Day 10, Week 4, and Month 3, to calculate MPA AUC(0-12). Free MPA AUC values were available for a subgroup of patients (n = 269). Results: The overall incidence of DGF was 187 of 830 (23%) and did not differ between cyclosporine-treated (24%) and tacrolimus- (21%) treated patients. The incidence of biopsy-proven acute rejection at 12 months was significantly higher in patients with DGF (13.8% versus 21.4%). Patients with DGF had significantly lower dose-corrected MPA AUC on Day 3 and Day 10. Free MPA fraction and dose-corrected free MPA AUC were significantly higher in patients with DGF, from Day 3 until Month 3. The total number of patients with at least one opportunistic infection was significantly higher in patients with DGF (33.2%) compared with patients without DGF (25.8%) (P = 0.048). Patients with DGF developing opportunistic infections did not have higher total MPA AUC nor higher free MPA AUC compared with those without opportunistic infections. Conclusion: Patients with DGF have significantly lower dose-corrected MPA AUC in the first month after renal transplantation, presumably as a result of enhanced MPA clearance on account of the elevated MPA free fraction. Because patients with DGF have a higher rate of acute rejection and lower MPA exposure, higher dosing of mycophenolate mofetil in such patients may improve outcome. However, the already increased incidence of opportunistic infections in patients with DGF is a concern. © 2011 by Lippincott Williams & Wilkins.
Vogel S.E.,University of Western Ontario |
Vogel S.E.,Georg August University Go ttingen |
Remark A.,University of Western Ontario |
Ansari D.,University of Western Ontario
Journal of Experimental Child Psychology | Year: 2014
A growing body of evidence has indicated a link between individual differences in children's symbolic numerical magnitude discrimination (e.g., judging which of two numbers is numerically larger) and their arithmetic achievement. In contrast, relatively little is known about the processing of numerical order (e.g., deciding whether two numbers are in ascending or descending numerical order) and whether individual differences in judging numerical order are related to the processing of numerical magnitude and arithmetic achievement. In view of this, we investigated the relationships among symbolic numerical magnitude comparison, symbolic order judgments, and mathematical achievement. Data were collected from a group of 61 first-grade children who completed a magnitude comparison task, an order judgment task, and two standardized tests of arithmetic achievement. Results indicated a numerical distance effect (NDE) in both the symbolic numerical magnitude discrimination and the numerical order judgment condition. However, correlation analyses demonstrated that although individual differences in magnitude comparison correlated significantly with arithmetic achievement, performance on the order judgment task did not. Moreover, the NDE of the magnitude and order comparison performance was also found to be uncorrelated. These findings suggest that order and numerical magnitude processing may be underpinned by different processes and relate differentially to arithmetic achievement in young children. © 2014 Elsevier Inc.
Dohler F.,University of Hamburg |
Sepulveda-Falla D.,University of Hamburg |
Krasemann S.,University of Hamburg |
Altmeppen H.,University of Hamburg |
And 5 more authors.
Brain | Year: 2014
Alzheimer's disease is the most common form of dementia and the generation of oligomeric species of amyloid-β is causal to the initiation and progression of it. Amyloid-β oligomers bind to the N-terminus of plasma membrane-bound cellular prion protein (PrPC) initiating a series of events leading to synaptic degeneration. Composition of bound amyloid-β oligomers, binding regions within PrPC, binding affinities and modifiers of this interaction have been almost exclusively studied in cell culture or murine models of Alzheimer's disease and our knowledge on PrP C-amyloid-β interaction in patients with Alzheimer's disease is limited regarding occurrence, binding regions in PrPC, and size of bound amyloid-β oligomers. Here we employed a PrPC-amyloid- β binding assay and size exclusion chromatography on neuropathologically characterized Alzheimer's disease and non-demented control brains (n = 15, seven female, eight male, average age: 79.2 years for Alzheimer's disease and n = 10, three female, seven male, average age: 66.4 years for controls) to investigate amyloid-β-PrPC interaction. PrPC-amyloid-β binding always occurred in Alzheimer's disease brains and was never detected in non-demented controls. Neither expression level of PrPC nor known genetic modifiers of Alzheimer's disease, such as the PrPC codon 129 polymorphism, influenced this interaction. In Alzheimer's disease brains, binding of amyloid-β to PrPC occurred via the PrPC N-terminus. For synthetic amyloid-β42, small oligomeric species showed prominent binding to PrPC, whereas in Alzheimer's disease brains larger protein assemblies containing amyloid-β42 bound efficiently to PrPC. These data confirm Alzheimer's disease specificity of binding of amyloid-β to PrPC via its N-terminus in a large cohort of Alzheimer's disease/control brains. Differences in sizes of separated protein fractions between synthetic and brain-derived amyloid-β binding to PrPC suggest that larger assemblies of amyloid-β or additional non-amyloid-β components may play a role in binding of amyloid-β42 to PrPC in Alzheimer's disease. © 2014 The Author .
Waltert M.,Georg August University Go ttingen |
Bobo K.S.,University of Dschang |
Leija Montoya M.,Autonomous University of Nuevo León |
Nsanyi M.S.,University of Buea |
Fermon H.,Georg August University Go ttingen
PLoS ONE | Year: 2011
Despite an increasing amount of data on the effects of tropical land use on continental forest fauna and flora, it is debatable whether the choice of the indicator variables allows for a proper evaluation of the role of modified habitats in mitigating the global biodiversity crisis. While many single-taxon studies have highlighted that species with narrow geographic ranges especially suffer from habitat modification, there is no multi-taxa study available which consistently focuses on geographic range composition of the studied indicator groups. We compiled geographic range data for 180 bird, 119 butterfly, 204 tree and 219 understorey plant species sampled along a gradient of habitat modification ranging from near-primary forest through young secondary forest and agroforestry systems to annual crops in the southwestern lowlands of Cameroon. We found very similar patterns of declining species richness with increasing habitat modification between taxon-specific groups of similar geographic range categories. At the 8 km2 spatial level, estimated richness of endemic species declined in all groups by 21% (birds) to 91% (trees) from forests to annual crops, while estimated richness of widespread species increased by +101% (trees) to +275% (understorey plants), or remained stable (- 2%, butterflies). Even traditional agroforestry systems lost estimated endemic species richness by - 18% (birds) to - 90% (understorey plants). Endemic species richness of one taxon explained between 37% and 57% of others (positive correlations) and taxon-specific richness in widespread species explained up to 76% of variation in richness of endemic species (negative correlations). The key implication of this study is that the range size aspect is fundamental in assessments of conservation value via species inventory data from modified habitats. The study also suggests that even ecologically friendly agricultural matrices may be of much lower value for tropical conservation than indicated by mere biodiversity value. © 2011 Waltert et al.
Siewert I.,Georg August University Go ttingen |
Gallezowska 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. Proton-coupled electron transfer: A cobalt complex with four NH protons in the ligand sphere was utilised as a water-oxidising electrocatalyst. We demonstrated that the combination of the redox-active metal ion and NH units enabled the coupling of proton- and electron-transfer steps (see figure). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Kindermann N.,Georg August University Go ttingen |
Bill E.,Max Planck Institute fu r chemische Energiekonversion |
Dechert S.,Georg August University Go ttingen |
Demeshko S.,Georg August University Go ttingen |
And 2 more authors.
Angewandte Chemie - International Edition | Year: 2014
Copper enzymes play important roles in the binding and activation of dioxygen in biological systems. Key copper/dioxygen intermediates have been identified and studied in synthetic analogues of the metalloprotein active sites, including the μ-η2:η2-peroxodicopper(II) motif relevant to type III dicopper proteins. Herein, we report the synthesis and characterization of a bioinspired dicopper system that forms a stable μ-η1:η1-peroxo complex whose Cu-O-O-Cu torsion is constrained to around 90° by ligand design. This results in sizeable ferromagnetic coupling between the copper(II) ions, which is detected by magnetic measurements and HF-EPR spectroscopy. The new dicopper peroxo system is the first with a triplet ground state, and it represents a snapshot of the initial stages of O2 binding at type III dicopper sites. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.