University of Warsaw

About: University of Warsaw is a education organization based out in Warsaw, Poland. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 20832 authors who have published 56617 publications receiving 1185084 citations. The organization is also known as: Uniwersytet Warszawski & Warsaw University.

Asymmetries in the Cosmic Microwave Background Anisotropy Field

Abstract: We report on the results from two independent but complementary statistical analyses of the Wilkinson Microwave Anisotropy Probe (WMAP) first-year data, based on the power spectrum and N-point correlation functions. We focus on large and intermediate scales (larger than about 3°) and compare the observed data against Monte Carlo ensembles with WMAP-like properties. In both analyses, we measure the amplitudes of the large-scale fluctuations on opposing hemispheres and study the ratio of the two amplitudes. The power-spectrum analysis shows that this ratio for WMAP, as measured along the axis of maximum asymmetry, is high at the 95%-99% level (depending on the particular multipole range included). The axis of maximum asymmetry of the WMAP data is weakly dependent on the multipole range under consideration but tends to lie close to the ecliptic axis. In the N-point correlation-function analysis, we focus on the northern and southern hemispheres defined in ecliptic coordinates, and we find that the ratio of the large-scale fluctuation amplitudes is high at the 98%-99% level. Furthermore, the results are stable with respect to choice of Galactic cut and also with respect to frequency band. A similar asymmetry is found in the COBE Differential Microwave Radiometer (DMR) map, and the axis of maximum asymmetry is close to the one found in the WMAP data.

Event generator tunes obtained from underlying event and multiparton scattering measurements

Abstract: New sets of parameters ("tunes") for the underlying-event (UE) modeling of the PYTHIA8, PYTHIA6 and HERWIG++ Monte Carlo event generators are constructed using different parton distribution functions. Combined fits to CMS UE data at sqrt(s) = 7 TeV and to UE data from the CDF experiment at lower sqrt(s), are used to study the UE models and constrain their parameters, providing thereby improved predictions for proton-proton collisions at 13 TeV. In addition, it is investigated whether the values of the parameters obtained from fits to UE observables are consistent with the values determined from fitting observables sensitive to double-parton scattering processes. Finally, comparisons of the UE tunes to "minimum bias" (MB) events, multijet, and Drell-Yan (q q-bar to Z / gamma* to lepton-antilepton + jets) observables at 7 and 8 TeV are presented, as well as predictions of MB and UE observables at 13 TeV.

Development of blastomeres of mouse eggs isolated at the 4- and 8-cell stage.

Abstract: Organization of a mammahan egg at the beginning of development has been the subject of several experimental as well as descriptive cytological and cytochemical investigations. The regulative capacities of blastomeres isolated at the 2-cell stage have been studied in the rat (Nicholas & Hall, 1942), rabbit (Seidel, 1952,1960) and mouse (Tarkowski, 1959 a, b ; Mulnard, 1965 a, b ). Investigations by Seidel and Tarkowski have shown that although the majority of 1/2 blastomeres can regulate and develop into smaller but otherwise normal blastocysts, som e of them give rise to purely trophoblastic vesicles devoid of the inner cell mass. In the mouse, Tarkowski (1959 a, b ) observed in addition in a few cases multicellular morulae which had not undergone cavitation. The findings of Tarkowski have been recently confirmed by Mulnard (1965 a, b ) who studied cytochemically mouse 1/2 blastomeres developing in vitro .