303 research outputs found
Effects of CP-violating phases in supersymmetry
Recent studies about the impact of the CP-violating complex parameters in
supersymmetry on the decays of third generation squarks and about T-odd
asymmetries in neutralino and chargino production and decay are reviewed. The
CP-even branching ratios of the third generation squarks show a pronounced
dependence on the phases of A_t, A_b, mu and M_1 in a large region of the
supersymmetric parameter space. This could have important implications for stop
and sbottom searches and the MSSM parameter determination in future collider
experiments. We have estimated the expected accuracy in the determination of
the parameters by global fits of measured masses, decay branching ratios and
production cross sections. We have found that the parameter A_t can be
determined with an error of 2 - 3%, whereas the error on A_b is likely to be of
the order of 50 - 100%. In addition we have studied CP-odd observables, like
asymmetries based on triple product correlations, which are necessary to
unambiguously establish CP violation. We have analysed these asymmetries in
neutralino and chargino production with subsequent three-body decays at the
International Linear Collider with longitudinally polarised beams in the MSSM
with complex parameters M_1 and mu. The asymmetries, which appear already at
tree-level because of spin correlation between production and decay, can be as
large as 20% and will therefore be an important tool for the search for
CP-violating effects in supersymmetry.Comment: 13 pages, LaTeX, 7 eps figures, uses appolb.cls, presented at the
final meeting of the European Network ``Physics at Colliders'', Montpellier,
September 26 - 27, 200
A study of the structure of jet turbulence producing jet noise
Characteristics of turbulent structure of mixing region near outlet of circular subsonic jet and production of jet nois
Glycine as crosslinking bridge in the LL-diaminopimelic acid containing murein of Propionibacterium peterssonii
A mean-field kinetic lattice gas model of electrochemical cells
We develop Electrochemical Mean-Field Kinetic Equations (EMFKE) to simulate
electrochemical cells. We start from a microscopic lattice-gas model with
charged particles, and build mean-field kinetic equations following the lines
of earlier work for neutral particles. We include the Poisson equation to
account for the influence of the electric field on ion migration, and
oxido-reduction processes on the electrode surfaces to allow for growth and
dissolution. We confirm the viability of our approach by simulating (i) the
electrochemical equilibrium at flat electrodes, which displays the correct
charged double-layer, (ii) the growth kinetics of one-dimensional
electrochemical cells during growth and dissolution, and (iii) electrochemical
dendrites in two dimensions.Comment: 14 pages twocolumn, 17 figure
Di-Tripeptides and Oligopeptides Are Taken Up via Distinct Transport Mechanisms in Lactococcus lactis
Di-Tripeptides and Oligopeptides Are Taken Up via Distinct Transport Mechanisms in Lactococcus lactis
Population dynamics of Agrobacterium vitis in two grapevine varieties during the vegetation period
In this work populations of Agrobacterium vitis were monitored within one year. Starting in the middle of May, the population density of A. vitis was screened every week in all parts of two-year-old MĂĽller-Thurgau and Riesling grapevines which were freed from A. vitis by thermotherapy and inoculated with A. vitis NW90. Every week, 5 plants of the two varieties were examined for A. vitis in new shoots, around the inoculation site, in one- and two-year-old parts of the stem, in the rootstock and in the roots. Beyond the inoculation site the A. vitis population density was too low for statistical evaluation of population dynamics. At the inoculation site a seasonal course of the A. vitis population was found in both grapevine varieties. The A. vitis population density was highest at the end of May, but little later it dropped to a low level during the sommer months. A second maximum of population density was determined in October which reached nearly the same value as in spring. Population density of A. vitis correlated to physiological changes of the grapevine plant during the vegetation period. Though the population dynamics of A. vitis followed parallel courses in both grapevine varieties, differences in the population density and in the onset of the autumn increase were determined. This could be attributed to physiological differences of the two varieties. The migration of pathogenic bacteria from the inoculation site to the roots took at least 15 weeks
Phase field theory of polycrystalline solidification in three dimensions
A phase field theory of polycrystalline solidification is presented that is
able to describe the nucleation and growth of anisotropic particles with
different crystallographic orientation in three dimensions. As opposed with the
two-dimensional case, where a single orientation field suffices, in three
dimensions, minimum three fields are needed. The free energy of grain
boundaries is assumed to be proportional to the angular difference between the
adjacent crystals expressed here in terms of the differences of the four
symmetric Euler parameters. The equations of motion for these fields are
obtained from variational principles. Illustrative calculations are performed
for polycrystalline solidification with dendritic, needle and spherulitic
growth morphologies.Comment: 7 pages, 4 figures, submitted to Europhysics Letters on 14th
February, 200
Phase-Field Formulation for Quantitative Modeling of Alloy Solidification
A phase-field formulation is introduced to simulate quantitatively
microstructural pattern formation in alloys. The thin-interface limit of this
formulation yields a much less stringent restriction on the choice of interface
thickness than previous formulations and permits to eliminate non-equilibrium
effects at the interface. Dendrite growth simulations with vanishing solid
diffusivity show that both the interface evolution and the solute profile in
the solid are well resolved
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