9,151 research outputs found
Light elements in massive single and binary stars
We highlight the role of the light elements (Li, Be, B) in the evolution of
massive single and binary stars, which is largely restricted to a diagnostic
value, and foremost so for the element boron. However, we show that the boron
surface abundance in massive early type stars contains key information about
their foregoing evolution which is not obtainable otherwise. In particular, it
allows to constrain internal mixing processes and potential previous mass
transfer event for binary stars (even if the companion has disappeared). It may
also help solving the mystery of the slowly rotating nitrogen-rich massive main
sequence stars.Comment: 10 pages, 8 figures, to appear in proc. IAU-Symp. 268. C. Charbonnel
et al., eds
Partially Quenched QCD with Non-Degenerate Dynamical Quarks
We discuss the importance of using partially quenched theories with three
degenerate quarks for extrapolating to QCD, and present some relevant results
from chiral perturbation theory.Comment: LATTICE99 talk. 3 pages, 2 figures. Uses epsf and espcrc2.st
Energy nonequipartition in a sheared granular mixture
The kinetic granular temperatures of a binary granular mixture in simple
shear flow are determined from the Boltzmann kinetic theory by using a Sonine
polynomial expansion. The results show that the temperature ratio is clearly
different from unity (as may be expected since the system is out of
equilibrium) and strongly depends on the restitution coefficients as well as on
the parameters of the mixture. The approximate analytical calculations are
compared with those obtained from Monte Carlo simulations of the Boltzmann
equation showing an excellent agreement over the range of parameters
investigated. Finally, the influence of the temperature differences on the
rheological properties is also discussed.Comment: 3 figure
Revealing frame dynamics through comparing associative fields in diachrony
The article shows that the changes of an associative field in diachrony can somewhat schematically, but quite accurately reflect the dynamics of the corresponding frame over time. The undertaken comparative analysis of associative fields of stimuli ‘napitok’ (drink) and ‘pit’yo’ (drink(ing)) - as of 1988-1997 (the data of “Russian associative dictionary”) and 2013-2014 (the results of the author experiment) - helps to develop the model of the frame “drink” - to the extent of slots actualized through associative reactions - and reveals some changes in its structure. Ascertained dynamics implies variation in the relevancy of almost all slots. The revealed trends also reflect some harmonization of this frame with its Western analoguesye
Application of Hartree-Fock theory of fluctuations to opacity calculation
The Hartree-Fock theory of fluctuations leading to simple formulae for configuration probabilities is used in a Detailed Configuration Accounting calculation of opacity in the case of an iron plasma. A direct Detailed Term Accounting method is also applied. The correlations of subshell occupation numbers, which are accounted for in the HF theory, show small effect on the theoretical spectrum corresponding to conditions of a recent measuremen
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