5,123 research outputs found

    Sprawozdanie z 28 Mi─Ödzynarodowego Kongresu Psychologicznego w Beijing (Chiny)

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    28 Mi─Ödzynarodowy Kongres Psychologii odby┼é si─Ö w Pekinie, w Chinach w dniach 8ÔÇô13 sierpnia 2004 r. Kongres ten odbywa┼é si─Ö pod auspicjami Mi─Ödzynarodowej Unii Nauk Psychologicznych. Siedzib─ů by┼éo nowoczesne Centrum Kongresowe mieszcz─ůce si─Ö w azjatyckiej wiosce olimpijskiej, niedaleko Starego Miasta. Kongres zgromadzi┼é blisko 5000 reprezentant├│w. Odby┼éo si─Ö 227 zaproszonych sympozj├│w, ponad 300 sesji tematycznych i blisko 2600 aktywnych sesji posterowych. Polsk─Ö reprezentowa┼éo ponad 30 uczestnik├│w, w tym dwoje z Instytutu Psychologii Uniwersytetu ┼ü├│dzkiego

    Pair extended coupled cluster doubles

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    The accurate and efficient description of strongly correlated systems remains an important challenge for computational methods. Doubly occupied configuration interaction (DOCI), in which all electrons are paired and no correlations which break these pairs are permitted, can in many cases provide an accurate account of strong correlations, albeit at combinatorial computational cost. Recently, there has been significant interest in a method we refer to as pair coupled cluster doubles (pCCD), a variant of coupled cluster doubles in which the electrons are paired. This is simply because pCCD provides energies nearly identical to those of DOCI, but at mean-field computational cost (disregarding the cost of the two-electron integral transformation). Here, we introduce the more complete pair extended coupled cluster doubles (pECCD) approach which, like pCCD, has mean-field cost and reproduces DOCI energetically. We show that unlike pCCD, pECCD also reproduces the DOCI wave function with high accuracy. Moreoever, pECCD yields sensible albeit inexact results even for attractive interactions where pCCD breaks down.Comment: submitted manuscrip

    Constraining Binary Evolution with Gravitational Wave Measurements of Chirp Masses

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    Using the StarTrack binary population synthesis code we investigate the properties of population of compact object binaries. Taking into account the selection effects we calculate the expected properties of the observed binaries.We analyze possible constraints on the stellar evolution models and find that an observed sample of about one hundred mergers will yield strong constraints on the binary evolution scenarios.Comment: Invited talk at "The Astrophysics of Gravitational Wave Sources" Workshop; April 24-26, 2003, U. Maryland; 10 page

    Distribution of binary mergers around galaxies

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    We use a stellar binary population synthesis code to find the lifetimes and velocities of several types of possible GRB progenitors: double neutron stars, black hole neutron stars, black hole white dwarfs, helium star mergers. Assuming that they are born in different types of galaxies we compute their spatial distribution and compare it with the observed locations of GRB afterglows within their hosts. We discuss constraints on the compact object merger model of GRBs imposed by this comparison and find that the observations of afterglows and their host galaxies appear inconsistent with the GRB compact object merger model.Comment: 5 pages, 2 figures, Latex with aipproc.sty, Proc. of the 5th Huntsville Gamma Ray Burst Symposium, Oct. 1999, ed. R.M. Kippen, AI

    Constraints on the Galactic Corona Models of Gamma-Ray Bursts From the 3B Catalogue

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    We investigate the viability of Galactic corona models of gamma-ray bursts by calculating the spatial distribution expected for a population of high-velocity neutron stars born in the Galactic disk and moving in a gravitational potential that includes the Galactic bulge, disk, and a dark matter halo. We consider models in which the bursts radiate isotropically and in which the radiation is beamed. We place constraints on the models by comparing the resulting brightness and angular distributions with the data in the BATSE 3B catalog. We find that, if the burst sources radiate isotropically, the Galactic corona model can reproduce the BATSE peak flux and angular distributions for neutron star kick velocities > 800 km sÔłĺ1^{-1}, source turn-on ages > 20 Myrs, and BATSE sampling distances 130 kpc < d_{max} < 350 kpc. If the radiation is beamed, no turn-on age is required and agreement with the BATSE data can be found provided that the width of the beam is less than 20 deg.Comment: 5 pages latex uses aip macros. To be published in the Proceedings of the 3rd Huntsville Gamma-Ray Burst Symposium, AIP editors C. Kouvelietou, M.S. Briggs, G.J. Fishma
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