857 research outputs found
Potential climate change impacts on the water balance of subcatchments of the River Spree, Germany
Lusatia is considered one of the driest regions of Germany. The climatic water balance is negative even under current climate conditions. Due to global climate change, increased temperatures and a shift of precipitation from summer to winter are expected. Therefore, it is of major interest whether the excess water in winter can be stored and to which extent it is used up on increasing evapotranspiration.
Thus, this study focuses on estimating potential climate change impacts on the water balance of two subcatchments of the River Spree using the Soil and Water Integrated Model (SWIM). Climate input was taken from 100 realisations each of two scenarios of the STatistical Analogue Resampling scheme STAR assuming a further temperature increase of 0 K (scenario A) and 2 K by the year 2055 (scenario B) respectively. Resulting from increased temperatures and a shift in precipitation from summer to winter actual evapotranspiration is supposed to increase in winter and early spring, but to decrease in later spring and early summer. This is less pronounced for scenario A than for scenario B. Consequently, also the decrease in discharge and groundwater recharge in late spring is lower for scenario A than for scenario B. The highest differences of runoff generation and groundwater recharge between the two scenarios but also the highest ranges within the scenarios occur in summer and early autumn. It is planned to estimate potential climate change for the catchments of Spree, Schwarze Elster and Lusatian Neisse
Electroweak Radiative Corrections to Weak Boson Production at Hadron Colliders
We summarize the status of calculations of the electroweak radiative
corrections to W and Z boson production via the Drell-Yan mechanism at hadron
colliders. To fully exploit the precision physics potential of the
high-luminosity environment of the Fermilab Tevatron pbar p (Run II) and the
CERN LHC pp colliders, it is crucial that the theoretical predictions are well
under control. The envisioned precision physics program includes a precise
measurement of the W boson mass and width, and the (leptonic) weak mixing
angle, as well as probing the Standard Model (SM) of electroweak interactions
at the highest accessible center-of-mass energies. Some numerical results are
presented.Comment: Latex, 5 pages, 4 figures, talk given by UB at RADCOR2002/Loops and
Legs, Kloster Banz, Germany, Sep. 2002, to appear in the Proceeding
Potential climate change impacts on the water balance of subcatchments of the River Spree, Germany
Lusatia is considered one of the driest regions of Germany. The climatic
water balance is negative even under current climate conditions. Due to
global climate change, increased temperatures and a shift of precipitation
from summer to winter are expected. Therefore, it is of major interest
whether the excess water in winter can be stored and to which extent it is
used up on increasing evapotranspiration.
Thus, this study focuses on estimating potential climate change impacts on
the water balance of two subcatchments of the River Spree using the Soil and
Water Integrated Model (SWIM). Climate input was taken from 100 realisations
each of two scenarios of the STatistical Analogue Resampling scheme STAR
assuming a further temperature increase of 0 K (scenario A) and 2 K by the
year 2055 (scenario B) respectively. Resulting from increased temperatures
and a shift in precipitation from summer to winter actual evapotranspiration
is supposed to increase in winter and early spring, but to decrease in later
spring and early summer. This is less pronounced for scenario A than for
scenario B. Consequently, also the decrease in discharge and groundwater
recharge in late spring is lower for scenario A than for scenario B. The
highest differences of runoff generation and groundwater recharge between
the two scenarios but also the highest ranges within the scenarios occur in
summer and early autumn. It is planned to estimate potential climate change
for the catchments of Spree, Schwarze Elster and Lusatian Neisse
Phonon-induced dephasing of localized optical excitations
The dynamics of strongly localized optical excitations in semiconductors is studied including electron-phonon interaction. The coupled microscopic equations of motion for the interband polarization and the carrier distribution functions contain coherent and incoherent contributions. While the coherent part is solved through direct numerical integration, the incoherent one is treated by means of a generalized Monte Carlo simulation. The approach is illustrated for a simple model system. The temperature and excitation energy dependence of the optical dephasing rate is analyzed and the results are compared to those of alternative approaches
Nonequilibrium relaxation and scaling properties of the two-dimensional Coulomb glass in the aging regime
We employ Monte Carlo simulations to investigate the two-time density
autocorrelation function for the two-dimensional Coulomb glass. We find that
the nonequilibrium relaxation properties of this highly correlated disordered
system can be described by a full aging scaling ansatz. The scaling exponents
are non-universal, and depend on temperature and charge density.Comment: 6 pages, 3 figures included; revised version: corrected exponents,
and some additional explanations and references added; to appear in EP
Theory of Exciton Migration and Field-Induced Dissociation in Conjugated Polymers
The interplay of migration, recombination, and dissociation of excitons in
disordered media is studied theoretically in the low temperature regime. An
exact expression for the photoluminescence spectrum is obtained. The theory is
applied to describe the electric field-induced photoluminescence-quenching
experiments by Kersting et al. [Phys. Rev. Lett. 73, 1440 (1994)] and Deussen
et al. [Synth. Met. 73, 123 (1995)] on conjugated polymer systems. Good
agreement with experiment is obtained using an on-chain dissociation mechanism,
which implies a separation of the electron-hole pair along the polymer chain.Comment: 4 pages, RevTeX, 2 Postscript figure
Physics at the e+ e- Linear Collider
A comprehensive review of physics at an e+e- Linear Collider in the energy
range of sqrt{s}=92 GeV--3 TeV is presented in view of recent and expected LHC
results, experiments from low energy as well as astroparticle physics.The
report focuses in particular on Higgs boson, Top quark and electroweak
precision physics, but also discusses several models of beyond the Standard
Model physics such as Supersymmetry, little Higgs models and extra gauge
bosons. The connection to cosmology has been analyzed as well.Comment: 179 pages, plots and references updated, version to be published at
EPJ
High specificity of BCL11B and GLG1 for EWSR1-FLI1 and EWSR1-ERG positive Ewing sarcoma
Ewing sarcoma (EwS) is an aggressive cancer displaying an undifferentiated small-round-cell histomorphology that can be easily confused with a broad spectrum of differential diagnoses. Using comparative transcriptomics and immunohistochemistry (IHC), we previously identified BCL11B and GLG1 as potential specific auxiliary IHC markers for EWSR1-FLI1-positive EwS. Herein, we aimed at validating the specificity of both markers in a far larger and independent cohort of EwS (including EWSR1-ERG-positive cases) and differential diagnoses. Furthermore, we evaluated their intra-tumoral expression heterogeneity. Thus, we stained tissue microarrays from 133 molecularly confirmed EwS cases and 320 samples from morphological mimics, as well as a series of patient-derived xenograft (PDX) models for BCL11B, GLG1, and CD99, and systematically assessed the immunoreactivity and optimal cut-offs for each marker. These analyses demonstrated that high BCL11B and/or GLG1 immunoreactivity in CD99-positive cases had a specificity of 97.5% and an accuracy of 87.4% for diagnosing EwS solely by IHC, and that the markers were expressed by EWSR1-ERG-positive EwS. Only little intra-tumoral heterogeneity in immunoreactivity was observed for differential diagnoses. These results indicate that BCL11B and GLG1 may help as specific auxiliary IHC markers in diagnosing EwS in conjunction with CD99, especially if confirmatory molecular diagnostics are not available
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