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Search Results: 1 - 10 of 139338 matches for " K. Schulze "
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Explicit Correlated Exciton-Vibrational Dynamics of the FMO Complex
Jan Schulze,Oliver Kühn
Physics , 2015, DOI: 10.1021/acs.jpcb.5b03928
Abstract: The coupled exciton-vibrational dynamics of a 3-site FMO model is investigated using the numerically exact multilayer multiconfiguration time-dependent Hartree approach. Thereby the vibrational mode specific coupling to local electronic transitions is adapted from a discretized experimental spectral density. The solution of the resulting time-dependent Schr\"odinger equation including three electronic and 450 vibrational degrees of freedom is analyzed in terms of excitonic populations and coherences. Emphasis is put onto the role of specific ranges of vibrational frequencies. It is observed that modes between 160 and 300 cm$^{-1}$ are responsible for the subpicosecond population and coherence decay. Further, it is found that a mean-field approach with respect to the vibrational degrees of freedom is not applicable.
Simulating river flow velocity on global scale
K. Schulze, M. Hunger,P. D ll
Advances in Geosciences (ADGEO) , 2005,
Abstract: Flow velocity in rivers has a major impact on residence time of water and thus on high and low water as well as on water quality. For global scale hydrological modeling only very limited information is available for simulating flow velocity. Based on the Manning-Strickler equation, a simple algorithm to model temporally and spatially variable flow velocity was developed with the objective of improving flow routing in the global hydrological model of WaterGAP. An extensive data set of flow velocity measurements in US rivers was used to test and to validate the algorithm before integrating it into WaterGAP. In this test, flow velocity was calculated based on measured discharge and compared to measured velocity. Results show that flow velocity can be modeled satisfactorily at selected river cross sections. It turned out that it is quite sensitive to river roughness, and the results can be optimized by tuning this parameter. After the validation of the approach, the tested flow velocity algorithm has been implemented into the WaterGAP model. A final validation of its effects on the model results is currently performed.
Center flux correlation in SU(2) Yang-Mills theory
K. Langfeld,G. Schulze,H. Reinhardt
Physics , 2005, DOI: 10.1103/PhysRevLett.95.221601
Abstract: By using the method of center projection the center vortex part of the gauge field is isolated and its propagator is evaluated in the center Landau gauge, which minimizes the open 3-dimensional Dirac volumes of non-trivial center links bounded by the closed 2-dimensional center vortex surfaces. The center field propagator is found to dominate the gluon propagator (in Landau gauge) in the low momentum regime and to give rise to an OPE correction to the latter of ${\sqrt{\sigma}}/{p^3}$.The screening mass of the center vortex field vanishes above the critical temperature of the deconfinement phase transition, which naturally explains the second order nature of this transition consistent with the vortex picture. Finally, the ghost propagator of maximal center gauge is found to be infrared finite and thus shows that the coset fields play no role for confinement.
Habitat width along a latitudinal gradient
D. Stauffer,C. Schulze,K. Rohde
Quantitative Biology , 2006,
Abstract: We use the Chowdhury ecosystem model, one of the most complex agent-based ecological models, to test the latitude-niche breadth hypothesis, with regard to habitat width, i.e., whether tropical species generally have narrower habitats than high latitude ones. Application of the model has given realistic results in previous studies on latitudinal gradients in species diversity and Rapoport's rule. Here we show that tropical species with sufficient vagility and time to spread into adjacent habitats, tend to have wider habitats than high latitude ones, contradicting the latitude-niche breadth hypothesis.
Experimental Examination of an Axial Compressor as a Basis for an Active Stall Avoidance System
Richard Schulze,Dietmar K. Hennecke,Thuyen Le,Manfred Glesner
International Journal of Rotating Machinery , 2000, DOI: 10.1155/s1023621x00000087
Abstract: A single-stage subsonic compressor was examined with respect to compressor instabilities. During the inception of rotating stall, the transients of the pressure rise and mass flow were measured as well as their hysteresis. The development of the stall cell and the characteristics of the unstable operating range were determined.
How accurately can soil organic carbon stocks and stock changes be quantified by soil inventories?
M. Schrumpf, E. D. Schulze, K. Kaiser,J. Schumacher
Biogeosciences (BG) & Discussions (BGD) , 2011,
Abstract: Precise determination of changes in organic carbon (OC) stocks is prerequisite to understand the role of soils in the global cycling of carbon and to verify changes in stocks due to management. A large dataset was collected to form base to repeated soil inventories at 12 CarboEurope sites under different climate and land-use, and with different soil types. Concentration of OC, bulk density (BD), and fine earth fraction were determined to 60 cm depth at 100 sampling points per site. We investigated (1) time needed to detect changes in soil OC, assuming future re-sampling of 100 cores; (2) the contribution of different sources of uncertainties to OC stocks; (3) the effect of OC stock calculation on mass rather than volume base for change detection; and (4) the potential use of pedotransfer functions (PTF) for estimating BD in repeated inventories. The period of time needed for soil OC stocks to change strongly enough to be detectable depends on the spatial variability of soil properties, the depth increment considered, and the rate of change. Cropland sites, having small spatial variability, had lower minimum detectable differences (MDD) with 100 sampling points (105 ± 28 gC m 2 for the upper 10 cm of the soil) than grassland and forest sites (206 ± 64 and 246 ± 64 gC m 2 for 0–10 cm, respectively). Expected general trends in soil OC indicate that changes could be detectable after 2–15 yr with 100 samples if changes occurred in the upper 10 cm of stone-poor soils. Error propagation analyses showed that in undisturbed soils with low stone contents, OC concentrations contributed most to OC stock variability while BD and fine earth fraction were more important in upper soil layers of croplands and in stone rich soils. Though the calculation of OC stocks based on equivalent soil masses slightly decreases the chance to detect changes with time at most sites except for the croplands, it is still recommended to account for changing bulk densities with time. Application of PTF for the estimation of bulk densities caused considerable underestimation of total variances of OC stocks if the error associated with the PTF was not accounted for, which rarely is done in soil inventories. Direct measurement of all relevant parameters approximately every 10 yr is recommended for repeated soil OC inventories.
How accurately can soil organic carbon stocks and stock changes be quantified by soil inventories?
M. Schrumpf,E. D. Schulze,K. Kaiser,J. Schumacher
Biogeosciences Discussions , 2011, DOI: 10.5194/bgd-8-723-2011
Abstract: Precise determination of changes in organic carbon (OC) stocks is prerequisite to understand the role of soils in the global cycling of carbon and to verify changes in stocks due to management. A large dataset was collected to form base to repeated soil inventories at 12 CarboEurope sites under different climate and land-use, and with different soil types. Concentration of OC, bulk density (BD), and fine earth fraction were determined to 60 cm depth at 100 sampling points per site. We investigated (1) time needed to detect changes in soil OC, assuming future re-sampling of 100 cores; (2) the contribution of different sources of uncertainties to OC stocks; (3) the effect of OC stock calculation on mass rather than volume base for change detection; and (4) the potential use of pedotransfer functions (PTF) for estimating BD in repeated inventories. The period of time needed for soil OC stocks to change strongly enough to be detectable depends on the spatial variability of soil properties, the depth increment considered, and the rate of change. Cropland sites, having small spatial variability, had lower minimum detectable differences (MDD) with 100 sampling points (105 ± 28 kg C m 2 for the upper 10 cm of the soil) than the grassland (206 ± 64 kg C m 2) and forest (246 ± 64 kg C m 2) sites. Expected general trends in soil OC indicate that changes could be detectable after 2–15 years with 100 samples if changes occurred in the upper 10 cm of stone-poor soils. Error propagation analyses showed that in undisturbed soils with low stone contents, OC concentrations contributed most to OC stock variability while BD and fine earth fraction were more important in upper soil layers of croplands and in stone rich soils. Though the calculation of OC stocks based on equivalent soil masses slightly decreases the chance to detect changes with time at most sites except for the croplands, it is still recommended to account for changing bulk densities with time. Application of PTF for the estimation of bulk densities caused considerable underestimation of total variances of OC stocks if the error associated with the PTF was not accounted for, which rarely is done in soil inventories. Direct measurement of all relevant parameters approximately every 10 years is recommended for repeated soil OC inventories.
Famili re hypokalziurische Hyperkalzi mie - aktuelle Diagnostik und Therapie
Raue F,Haag C,Schulze E,Frank-Raue K
Journal für Mineralstoffwechsel , 2009,
Abstract: Die famili re hypokalziurische Hyperkalzi mie (FHH) ist ein autosomal dominant vererbtes Leiden, bedingt durch eine heterozygote inaktivierende Mutation im Kalzium-sensing-Rezeptor (CaSR) mit lebenslang bestehender Hyperkalzi mie und relativer Hypokalziurie. Das Parathormon ist inad quat hoch, gemessen am Kalzium als Ausdruck der PTH-Resistenz. Der Ph notyp ist asymptomatisch, selten findet man Nierensteine. Der Schlüssel zur Diagnose ist der Kalzium/Kreatininclearance-Quotient unter 0,01. Patienten mit FHH werden gelegentlich als Patienten mit asymptomatischem prim rem Hyperparathyreoidismus (pHpt) fehldiagnostiziert und parathyreoidektomiert, der Serum-Kalziumspiegel bleibt jedoch erh ht. Die molekulargenetische Analyse des CaSR erlaubt die wichtige Differentialdiagnose zum pHpt. Das seltene und lebensbedrohliche Syndrom des neonatalen schweren Hyperparathyreoidismus (NSHPT) mit ausgepr gter Hyperkalzi mie ist durch eine homozygote Mutation im CaSR bedingt und bedarf einer notfallm igen totalen Parathyreoidektomie.
Testing: A Systemic Functional View of High Stakes Test Preparation Materials
Schulze,Joshua;
Colombian Applied Linguistics Journal , 2009,
Abstract: educators of english language learners (ells) frequently use test preparation materials to help ells prepare for high stakes language exams. this study uses tools of systemic functional linguistics (sfl) to examine how academic language is used to construct meaning within these test preparation materials. while the test preparation materials and available test excerpts contain a range of genres, this study focuses particularly on informational texts with scientific topics, designed for upper elementary students. the results highlight pedagogical advantages of using sfl to develop genre awareness in ells by attending to the linguistic features evident in the genre.
Respek vir die liturgiese teks: J. Calvyn en J.S. Bach
LF Schulze
Acta Theologica , 2008,
Abstract: Despite obvious differences in terms of historical and theological aspects between Calvin and Bach, both share a respect for the priority of the Biblical text in worship.The anomaly between Calvin’s engagement in the versification of the Psalter and Bach’s preference for the literal (rather than a versified) use of the Biblical text (for example in his St. Matthew Passion) is rooted in their common respect for the Word of God originating from the Reformation
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