Daniel Richter

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Understanding what governs patterns of soil δ15N and δ13C is limited by the absence of these data assembled throughout the development of individual ecosystems. These patterns are important because stable isotopes of soil organic N and C are integrative indicators of biogeochemical processing of soil organic matter. We examined δ15N of soil organic matter(More)
BACKGROUND Fiber regulates the rate and site of lipid and carbohydrate digestion and absorption and thus can modify the alimentary responses to a meal. When fiber sources containing viscous polysaccharides are included in a meal, a slower rate of carbohydrate and lipid absorption will modify the alimentary hormone and lipid responses. OBJECTIVE We(More)
The tryptophan (trp)-catabolizing enzyme indolamine 2,3-dioxygenase (IDO) is induced by the T helper 1 (Th 1) cytokine IFN-gamma during infections in various tissues including the brain. Recent studies demonstrated an immune modulatory function of this enzyme, since IDO-mediated depletion of trp hinders T cell proliferation, while its inhibition by(More)
Local and peripheral immune responses are activated after ischemic stroke. In our present study, we investigated the temporal distribution, location, induction, and function of regulatory T cells (Tregs) and the possible involvement of microglia, macrophages, and dendritic cells after middle cerebral artery occlusion (MCAO). C57BL/6J and Foxp3(EGFP)(More)
In March 2006 two instrumented aircraft made the first detailed field measurements of biomass burning (BB) emissions in the Northern Hemisphere tropics as part of the MILAGRO project. The aircraft were the National Center for Atmospheric Research C-130 and a University of Montana/US Forest Service Twin Otter. The initial emissions of up to 49 trace gas or(More)
In addition to South Africa, the Northwestern corner of the African continent is providing a wealth of data for the understanding of the behaviour of early modern humans. In NW Africa, this modern behaviour is associated with a technocomplex called 'Aterian'. However, its definition as well as chronological position is heavily debated. As a common notion,(More)
Seeds of Gliricidia sepium (Jacq.) Walp., a tree native to seasonal tropical forests of Central America, were inoculated with N-fixing Rhizobium bacteria and grown in growth chambers for 71 days to investigate interactive effects of atmospheric CO2 and plant N status on early seedling growth, nodulation, and N accretion. Seedlings were grown with CO2(More)
In order to better predict soil sinks of methane, we need to examine soil methane ̄ux patterns and responses to altered soil moisture regimes. Estimates of the global atmospheric CH4 budget must also account for ̄uxes in the vast boreal region. We measured methane ̄uxes into the soil surface, methane concentrations, water content, and temperature in the(More)