2,727 research outputs found
Skewness-kurtosis adjusted confidence estimators and significance tests
First and second kind modifications of usual confidence intervals for
estimating the expectation and of usual local alternative parameter choices are
introduced in a way such that the asymptotic behavior of the true non-covering
probabilities and the covering probabilities under the modified local non-true
parameter assumption can be asymptotically exactly controlled. The orders of
convergence to zero of both types of probabilities are assumed to be suitably
bounded below according to an Osipov-type condition and the sample distribution
is assumed to satisfy a corresponding tail condition due to Linnik. Analogous
considerations are presented for the power function when testing a hypothesis
concerning the expectation both under the assumption of a true hypothesis as
well as under a modified local alternative. Applications are given for
exponential families.Comment: 8 page
The nodal structure of doubly-excited resonant states of helium
The authors examine the nodal structure of accurate helium wavefunctions calculated by direct diagonalization of the full six-dimensional problem. It is shown that for fixed interelectronic distance R (or hyperspherical radius R) the symmetric doubly-excited resonant states have well defined lambda , mu nodal structure indicating a near separability in prolate spheroidal coordinates. For fixed lambda , however, a clear mixing of R, mu nodes is demonstrated. This corresponds to a breakdown of the adiabatic approximation and can be understood in terms of the classical two-electron motion
Non-perturbative Yukawa Couplings from String Instantons
Non-perturbative D-brane instantons can generate perturbatively absent though
phenomenologically relevant couplings for Type II orientifold compactifications
with D-branes. We discuss the generation of the perturbatively vanishing SU(5)
GUT Yukawa coupling of type 10 10 5_H. Moreover, for a simple globally
consistent intersecting D6-brane model, we discuss the generation of mass terms
for matter fields. This can serve as a mechanism for decoupling exotic matter.Comment: 4 pages, 2 tables, 2 figure
Next-to-leading order QCD corrections to Z boson pair production via vector-boson fusion
Vector-boson fusion processes are an important tool for the study of
electroweak symmetry breaking at hadron colliders, since they allow to
distinguish a light Higgs boson scenario from strong weak boson scattering. We
here consider the channels WW->ZZ and ZZ->ZZ as part of electroweak Z boson
pair production in association with two tagging jets. We present the
calculation of the NLO QCD corrections to the cross sections for p p -> e+ e-
mu+ mu- + 2 jets and p p -> e+ e- nu_mu nubar_mu + 2 jets via vector-boson
fusion at order alpha_s alpha^6, which is performed in the form a NLO
parton-level Monte Carlo program. The corrections to the integrated cross
sections are found to be modest, while the shapes of some kinematical
distributions change appreciably at NLO. Residual scale uncertainties typically
are at the few percent level.Comment: 12 pages, 4 figure
Degradation of the yeast MATα2 transcriptional regulator is mediated by the proteasome
AbstractRapid degradation of specific regulatory proteins plays a role in a wide range of cellular phenomena, including cell cycle progression and the regulation of cell growth and differentiation. A major mechanism of selective protein turnover in vivo involves a large multi-subunit protease known as the proteasome or multi-catalytic proteinase. At the same time, the degradation of many cellular proteins requires their covalent ligation to the polypeptide ubiquitin. Here we show that the yeast S cerevisiae MATα2 repressor, which is known to be ubiquitinylated in vivo, requires the proteasome for its rapid intracellular proteolysis
Convex and Radially Concave Contoured Distributions
Integral representations of the locally defined star-generalized surface content measures on star spheres are derived for boundary spheres of balls being convex or radially concave with respect to a fan in Rn. As a result, the general geometric measure representation of star-shaped probability distributions and the general stochastic representation of the corresponding random vectors allow additional specific interpretations in the two mentioned cases. Applications to estimating and testing hypotheses on scaling parameters are presented, and two-dimensional sample clouds are simulated
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