517 research outputs found
Possible Supersymmetric Effects on Angular Distributions in Decays
We investigate the angular distributions of the rare B decay, , in general supersymmetric extensions of the standard
model. We consider the new physics contributions from the operators
in small invariant mass region of lepton pair. We show that the
azimuthal angle distribution of the decay can tell us the new physics effects
clearly from the behavior of the distribution, even if new physics does not
change the decay rate substantially from the standard model prediction
From the exclusive photoproduction of heavy quarkonia at HERA to the EDDE at TeVatron and LHC
Exclusive photoproduction of heavy quarkonia at HERA is analyzed in the
framework of the Regge-eikonal approach together with the nonrelativistic bound
state formalism. Total and differential cross-sections for the process
are calculated. The model predicts
cross-sections of Exclusive Double Diffractive Events (EDDE) at TeVatron and
LHC.Comment: 14 pages, 6 figures, reference is adde
Measuring sin 2\beta in Bs(t) -> phi K_s
We show that, unlike other pure b -> d penguin processes, the decay Bs(t) ->
phi K_s is dominated by a single amplitude, that of the internal t-quark. The
contributions of the u- and c-quark operators each vanish due to a cancellation
between the (V-A) \otimes (V-A) and (V-A) \otimes (V+A) matrix elements. Thus,
the indirect CP asymmetry in this decay probes sin 2\beta. Although this
cancellation is complete only for certain values of the s- and b-quark masses,
the theoretical uncertainty on sin 2\beta is still less than 10% over most
(~80%) of the parameter space. By measuring the direct CP asymmetry, one can
get a better idea of the probable error on sin 2\beta.Comment: 15 pages, LaTeX, 4 figure
The Elderly-Nutrient Rich Food Score Is Associated With Biochemical Markers of Nutritional Status in European Older Adults
Background: In order to prevent age-related degenerative diseases in the aging population, their diets should be nutrient dense. For this purpose, the Elderly-Nutrient rich food (E-NRF7.3) score has been developed to assess nutrient density of diets by capturing dietary reference values for older adults. To demonstrate its practical importance such score should be validated against markers of nutritional status and health. Objective: The objective of this study was to examine the association between the E-NRF7.3 score and markers of nutritional status and inflammation. Design: This study was carried out in a sample of the NU-AGE study including 242 Dutch and 210 Polish men and women, aged 65\u201379 years. Dietary intake was assessed by means of 7-day food records and structured questionnaires collected data on supplement use, lifestyle, and socio-economic information. Baseline measurements included anthropometrics, physical and cognitive function tests, and a fasting venipuncture. E-NRF7.3 scores were calculated to estimate nutrient density of foods and the diet. Associations between the E-NRF7.3 scores and micronutrient status of vitamin D, folate, vitamin B12, homocysteine, and c-reactive protein (CRP) were examined using linear regression analysis while adjusting for confounders. Results: Each one unit increase in E-NRF7.3 score was associated with a 2.2% increase in serum folate in Dutch and 1.6% increase in Polish participants in the fully adjusted models (both p < 0.01). Each one unit increase in E-NRF7.3 was significantly associated with a 1.5% decrease in homocysteine levels in Dutch participants (p < 0.01), whereas, a 0.9% increase in vitamin B12 levels was observed in Polish participants only (p < 0.01). Higher E-NRF7.3 scores were not associated with vitamin D or CRP levels. Adjustment for potential confounders did not substantially alter these results. Discussion: The E-NRF7.3 was developed to reflect dietary intake of relevant nutrients for older adults. Its association with markers of nutritional status could be confirmed for folate (both populations), vitamin B12 (Poland only), and homocysteine (the Netherlands only). There was no association with vitamin D and CRP. To further demonstrate its validity and practical implication, future studies should include a wider range of nutritional status makers, health outcomes, and inflammation markers
Conductance of tubular nanowires with disorder
We calculate the conductance of tubular-shaped nanowires having many
potential scatterers at random positions. Our approach is based on the
scattering matrix formalism and our results analyzed within the scaling theory
of disordered conductors. When increasing the energy the conductance for a big
enough number of impurities in the tube manifests a systematic evolution from
the localized to the metallic regimes. Nevertheless, a conspicuous drop in
conductance is predicted whenever a new transverse channel is open. Comparison
with the semiclassical calculation leading to purely ohmic behavior is made.Comment: 8 pages, 5 figure
Biological Rhythms Workshop I: Introduction to Chronobiology
In this chapter, we present a series of four articles derived from a Introductory Workshop on Biological Rhythms presented at the 72nd Annual Cold Spring Harbor Symposium on Quantitative Biology: Clocks and Rhythms. A diverse range of species, from cyanobacteria to humans, evolved endogenous biological clocks that allow for the anticipation of daily variations in light and temperature. The ability to anticipate environmental variation promotes optimal performance and survival. In the first article, Introduction to Chronobiology, we present a brief historical timeline of how circadian concepts and terminology have emerged since the early observation of daily leaf movement in plants made by an astronomer in the 1700s. Workshop Part IA provides an overview of the molecular basis for rhythms generation in several key model organisms, Workshop Part IB focuses on how biology built a brain clock capable of coordinating the daily timing of essential brain and physiological processes, and Workshop Part IC gives key insight into how researchers study sleep and rhythms in humans
Investigating the topology of interacting networks - Theory and application to coupled climate subnetworks
Network theory provides various tools for investigating the structural or
functional topology of many complex systems found in nature, technology and
society. Nevertheless, it has recently been realised that a considerable number
of systems of interest should be treated, more appropriately, as interacting
networks or networks of networks. Here we introduce a novel graph-theoretical
framework for studying the interaction structure between subnetworks embedded
within a complex network of networks. This framework allows us to quantify the
structural role of single vertices or whole subnetworks with respect to the
interaction of a pair of subnetworks on local, mesoscopic and global
topological scales.
Climate networks have recently been shown to be a powerful tool for the
analysis of climatological data. Applying the general framework for studying
interacting networks, we introduce coupled climate subnetworks to represent and
investigate the topology of statistical relationships between the fields of
distinct climatological variables. Using coupled climate subnetworks to
investigate the terrestrial atmosphere's three-dimensional geopotential height
field uncovers known as well as interesting novel features of the atmosphere's
vertical stratification and general circulation. Specifically, the new measure
"cross-betweenness" identifies regions which are particularly important for
mediating vertical wind field interactions. The promising results obtained by
following the coupled climate subnetwork approach present a first step towards
an improved understanding of the Earth system and its complex interacting
components from a network perspective
Higgs-Boson Production Associated with a Single Bottom Quark in Supersymmetric QCD
Due to the enhancement of the couplings between Higgs boson and bottom quarks
in the minimal sypersymmetric standard model (MSSM), the cross section of the
process pp(p\bar{p}) \to h^0b(h^0\bar{b})+X at hadron colliders can be
considerably enhanced. We investigated the production of Higgs boson associated
with a single high-p_T bottom quark via subprocess bg(\bar{b}g) \to
h^0b(h^0\bar{b}) at hadron colliders including the next-to-leading order (NLO)
QCD corrections in MSSM. We find that the NLO QCD correction in the MSSM
reaches 50%-70% at the LHC and 60%-85% at the Fermilab Tevatron in our chosen
parameter space.Comment: accepted by Phys. Rev.
The fully differential single-top-quark cross section in next-to-leading order QCD
We present a new next-to-leading order calculation for fully differential
single-top-quark final states. The calculation is performed using phase space
slicing and dipole subtraction methods. The results of the methods are found to
be in agreement. The dipole subtraction method calculation retains the full
spin dependence of the final state particles. We show a few numerical results
to illustrate the utility and consistency of the resulting computer
implementations.Comment: 37 pages, latex, 2 ps figure
Pseudoscalar Higgs boson production associated with a single bottom quark at hadron colliders
We compute the complete next-to-leading order (NLO) SUSY-QCD corrections for
the associated production of a pseudoscalar Higgs boson with a bottom quark via
bottom-gluon fusion at the CERN Large Hadron Collider (LHC) and the Fermilab
Tevatron. We find that the NLO QCD correction in the MSSM reaches
at the LHC and at the Tevatron in our chosen parameter space
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