76 research outputs found
Standard SANC modules for NLO QCD Radiative Corrections to Single-top Production
It this paper we present the results obtained with the newly created Standard
SANC modules for calculation of the NLO QCD corrections to single top
production processes in s and t channels at the partonic level, as well as
top-decays. The main aim of these results is to prove the correct work of
modules. A comprehensive comparison with results of the CompHEP system is
given, where possible. These modules are intended to be used in Monte Carlo
generators for single top production processes at the LHC. As in our recent
paper, devoted to the electroweak corrections to these processes, we study the
regularization of the top-legs associated infrared divergences with aid of the
complex mass of the top quark. A comparison of QCD corrections with those
computed by the conventional method is presented both for top production and
decays. For s channel production we give an analytic proof of equivalence of
the two methods in the limit of low top width.Comment: 21 pages, 2 figures, 17 table
Maximum Cliques in Protein Structure Comparison
Computing the similarity between two protein structures is a crucial task in
molecular biology, and has been extensively investigated. Many protein
structure comparison methods can be modeled as maximum clique problems in
specific k-partite graphs, referred here as alignment graphs. In this paper, we
propose a new protein structure comparison method based on internal distances
(DAST) which is posed as a maximum clique problem in an alignment graph. We
also design an algorithm (ACF) for solving such maximum clique problems. ACF is
first applied in the context of VAST, a software largely used in the National
Center for Biotechnology Information, and then in the context of DAST. The
obtained results on real protein alignment instances show that our algorithm is
more than 37000 times faster than the original VAST clique solver which is
based on Bron & Kerbosch algorithm. We furthermore compare ACF with one of the
fastest clique finder, recently conceived by Ostergard. On a popular benchmark
(the Skolnick set) we observe that ACF is about 20 times faster in average than
the Ostergard's algorithm
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Latitudinal wave coupling of the stratosphere and mesosphere during the major stratospheric warming in 2003/2004
The coupling of the dynamical regimes in the high- and low-latitude stratosphere and mesosphere during the major SSW in the Arctic winter of 2003/2004 has been studied. The UKMO zonal wind data were used to explore the latitudinal coupling in the stratosphere, while the coupling in the mesosphere was investigated by neutral wind measurements from eleven radars situated at high, high-middle and tropical latitudes. It was found that the inverse relationship between the variability of the zonal mean flows at high- and low-latitude stratosphere related to the SSW is produced by global-scale zonally symmetric waves. Their origin and other main features have been investigated in detail. Similar latitudinal dynamical coupling has been found for the mesosphere as well. Indirect evidence for the presence of zonally symmetric waves in the mesosphere has been found
Latitudinal wave coupling of the stratosphere and mesosphere during the major stratospheric warming in 2003/2004
Value Added from Money Managers in Private Markets? An Examination of Pension Fund Investments in Real Estate
Structure and relaxations in liquid and amorphous Selenium
We report a molecular dynamics simulation of selenium, described by a
three-body interaction. The temperatures T_g and T_c and the structural
properties are in agreement with experiment. The mean nearest neighbor
coordination number is 2.1. A small pre-peak at about 1 AA^-1 can be explained
in terms of void correlations. In the intermediate self-scattering function,
i.e. the density fluctuation correlation, classical behavior, alpha- and
beta-regimes, is found. We also observe the plateau in the beta-regime below
T_g. In a second step, we investigated the heterogeneous and/or homogeneous
behavior of the relaxations. At both short and long times the relaxations are
homogeneous (or weakly heterogeneous). In the intermediate time scale, lowering
the temperature increases the heterogeneity. We connect these different domains
to the vibrational (ballistic), beta- and alpha-regimes. We have also shown
that the increase in heterogeneity can be understood in terms of relaxations
Solar activity impact on the Earth’s upper atmosphere
The paper describes results of the studies devoted to the solar activity impact on the Earth’s upper atmosphere and ionosphere,
conducted within the frame of COST ES0803 Action.
Aim: The aim of the paper is to represent results coming from different research groups in a unified form, aligning their specific topics into the general context of the subject.
Methods: The methods used in the paper are based on data-driven analysis. Specific databases are used for spectrum analysis,
empirical modeling, electron density profile reconstruction, and forecasting techniques.
Results: Results are grouped in three sections: Medium- and long-term ionospheric response to the changes in solar and geomag-
netic activity, storm-time ionospheric response to the solar and geomagnetic forcing, and modeling and forecasting techniques.
Section 1 contains five subsections with results on 27-day response of low-latitude ionosphere to solar extreme-ultraviolet (EUV)
radiation, response to the recurrent geomagnetic storms, long-term trends in the upper atmosphere, latitudinal dependence of total electron content on EUV changes, and statistical analysis of ionospheric behavior during prolonged period of solar activity.
Section 2 contains a study of ionospheric variations induced by recurrent CIR-driven storm, a case-study of polar cap absorption
due to an intense CME, and a statistical study of geographic distribution of so-called E-layer dominated ionosphere.
Section 3 comprises empirical models for describing and forecasting TEC, the F-layer critical frequency foF2, and the height of
maximum plasma density. A study evaluates the usefulness of effective sunspot number in specifying the ionosphere state. An
original method is presented, which retrieves the basic thermospheric parameters from ionospheric sounding data
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State pension funds and corporate social responsibility: do beneficiaries’ political values influence funds’ investment decisions?
This study explores the underlying drivers of US public pension funds’ tendency to tilt their portfolios towards companies with stronger corporate social responsibility (CSR). Studying the equity holdings of large, internally-managed US state pension funds, we find evidence that the political leaning of their beneficiaries and political pressures by state politicians affect funds’ investment decisions. State pension funds from states with Democratic-leaning beneficiaries tilt their portfolios more strongly towards companies that perform well on CSR issues, and this tendency is intensified when the state government is dominated by Democratic state politicians. Moreover, we find that funds which tilt their portfolios towards companies with superior CSR scores generate a slightly higher return compared with their counterparts. Overall, our findings indicate that funds align their investment choices with the financial and non-financial interests of their beneficiaries when deciding whether to incorporate CSR into their equity allocations
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