University of Göttingen

About: University of Göttingen is a education organization based out in Göttingen, Germany. It is known for research contribution in the topics: Population & Gene. The organization has 43851 authors who have published 86318 publications receiving 3010295 citations. The organization is also known as: Georg-August-Universität Göttingen & Universität Göttingen.

Consequences of biodiversity loss for litter decomposition across biomes

Abstract: 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.

Recombinant Human Erythropoietin in the Treatment of Acute Ischemic Stroke

Abstract: Background and Purpose— Numerous preclinical findings and a clinical pilot study suggest that recombinant human erythropoietin (EPO) provides neuroprotection that may be beneficial for the treatment of patients with ischemic stroke. Although EPO has been considered to be a safe and well-tolerated drug over 2 decades, recent studies have identified increased thromboembolic complications and/or mortality risks on EPO administration to patients with cancer or chronic kidney disease. Accordingly, the double-blind, placebo-controlled, randomized German Multicenter EPO Stroke Trial (Phase II/III; ClinicalTrials.gov Identifier: NCT00604630) was designed to evaluate efficacy and safety of EPO in stroke. Methods— This clinical trial enrolled 522 patients with acute ischemic stroke in the middle cerebral artery territory (intent-to-treat population) with 460 patients treated as planned (per-protocol population). Within 6 hours of symptom onset, at 24 and 48 hours, EPO was infused intravenously (40 000 IU each). Sys...

Relevance of the Heisenberg-Kitaev model for the honeycomb lattice iridates A2IrO3.

Abstract: Combining thermodynamic measurements with theoretical calculations we demonstrate that the iridates ${A}_{2}{\mathrm{IrO}}_{3}$ ($A=\mathrm{Na}$, Li) are magnetically ordered Mott insulators where the magnetism of the effective spin-orbital $S=1/2$ moments can be captured by a Heisenberg-Kitaev (HK) model with interactions beyond nearest-neighbor exchange. Experimentally, we observe an increase of the Curie-Weiss temperature from $\ensuremath{\theta}\ensuremath{\approx}\ensuremath{-}125\text{ }\text{ }\mathrm{K}$ for ${\mathrm{Na}}_{2}{\mathrm{IrO}}_{3}$ to $\ensuremath{\theta}\ensuremath{\approx}\ensuremath{-}33\text{ }\text{ }\mathrm{K}$ for ${\mathrm{Li}}_{2}{\mathrm{IrO}}_{3}$, while the ordering temperature remains roughly the same ${T}_{N}\ensuremath{\approx}15\text{ }\text{ }\mathrm{K}$. Using functional renormalization group calculations we show that this evolution of $\ensuremath{\theta}$ and ${T}_{N}$ as well as the low temperature zigzag magnetic order can be captured within this extended HK model. We estimate that ${\mathrm{Na}}_{2}{\mathrm{IrO}}_{3}$ is deep in a magnetically ordered regime, while ${\mathrm{Li}}_{2}{\mathrm{IrO}}_{3}$ appears to be close to a spin-liquid regime.

α-Synuclein and tau concentrations in cerebrospinal fluid of patients presenting with parkinsonism: a cohort study

Abstract: Summary Background Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy are brain disorders characterised by intracellular α-synuclein deposits. We aimed to assess whether reduction of α-synuclein concentrations in CSF was a marker for α-synuclein deposition in the brain, and therefore diagnostic of synucleinopathies. Methods We assessed potential extracellular-fluid markers of α-synuclein deposition in the brain (total α-synuclein and total tau in CSF, and total α-synuclein in serum) in three cohorts: a cross-sectional training cohort of people with Parkinson's disease, multiple system atrophy, dementia with Lewy bodies, Alzheimer's disease, or other neurological disorders; a group of patients with autopsy-confirmed dementia with Lewy bodies, Alzheimer's disease, or other neurological disorders (CSF specimens were drawn ante mortem during clinical investigations); and a validation cohort of patients who between January, 2003, and December, 2006, were referred to a specialised movement disorder hospital for routine inpatient admission under the working diagnosis of parkinsonism. CSF and serum samples were assessed by ELISA, and clinical diagnoses were made according to internationally established criteria. Mean differences in biomarkers between diagnostic groups were assessed with conventional parametric and non-parametric statistics. Findings In our training set (n=273), people with Parkinson's disease, multiple system atrophy, and dementia with Lewy bodies had lower CSF α-synuclein concentrations than patients with Alzheimer's disease and other neurological disorders. CSF α-synuclein and tau values separated participants with synucleinopathies well from those with other disorders (p Interpretation Mean CSF α-synuclein concentrations as measured by ELISA are significantly lower in Parkinson's disease, dementia with Lewy bodies, and multiple system atrophy than in other neurological diseases. Although specificity was low, the high positive predictive value of CSF α-synuclein concentrations in patients presenting with synucleinopathy-type parkinsonism might be useful in stratification of patients in future clinical trials. Funding American Parkinson Disease Association, Stifterverband fur die Deutsche Wissenschaft, Michael J Fox Foundation for Parkinson's Research, National Institutes of Health, Parkinson Research Consortium Ottawa, and the Government of Canada.