Experimental test of the probability density function of true value of Poisson distribution parameter by single observation of number of events

The empirical probability density function for the conditional distribution of the true value of Poisson distribution parameter on one measurement is constructed by computer experiment. The analysis of the obtained distributions confirms that these distributions are gamma-distributions.Comment: presented in the IX International Workshop on Advanced Computing and Analysis Techniques in Physics Research (ACAT'03), KEK, Tsukuba, Japan, December 1-5, 200

Study on possible role of CYP1A1, GSTT1, GSTM1, GSTP1, NAT2 and ADRB2 genes polymorphisms in bronchial asthma development in children

Aim. To study the association of polymorphisms of the enzymes genes CYP1A1 (T6235C), first phase, and NAT2 (Ñ481Ò, G590A, G857A), GSTM1 («0»), GSTT1 («0») and GSTP1 (A313G), second phase of the detoxication system, as well as the ADRB2 (C79G) gene variants with the development of bronchial asthma in children. Methods. Polymorphic variants were analyzed using PCR followed by RFLP analysis in 86 healthy individuals and in 114 patients with clinical diagnosis of bronchial asthma. Results. The frequency of gene polymorphic variants of the enzymes of first and second phases of detoxification system as well as the ADRB2 gene was established in the children with bronchial asthma and healthy individuals. Conclusions. Ðolymorphic variants of the genes NAT2 (481Ò), GSTP1 (313G) and ADRB2 (79G) and their combinations in geno- type were observed more frequently in the patients with bronchial asthma comparing to the control group, which indicates their invol- vement in the pathogenesis of asthma in children Keywords: bronchial asthma, detoxication system, 2-adrenoreceptor gene, polymorphism, combined genotype.Мета. Дослідити зв’язок поліморфних варіантів генів ферментів першої – CYP1A1 (T6235C) та другої – NAT2 (С481Т, G590A, G857A), GSTM1 («0»), GSTT1 («0») і GSTP1 (A313G) фаз системи детоксикації, а також гена ADRB2 (C79G) з розвитком бронхіальної астми (БА) у дітей. Методи. Поліморфні варіанти вивчали за допомогою ПЛР та ПДРФ-аналізу у 86 здорових індивідів та у 114 пацієнтів з клінічним діагнозом БА. Результати. Встановлено частоту поліморфних варіантів генів ферментів першої і другої фаз системи детоксикації, а також гена ADRB2 у хворих на БА дітей та у здорових індивідів. Висновки. Поліморфні варіанти генів NAT2 (481Т), GSTP1 (313G) і ADRB2 (79G) та їхні комбінації в генотипі частіше спостерігаються серед пацієнтів з БА порівняно з контрольною групою, що свідчить на користь залучення їх до патогенезу БА у дітей. Ключові слова: бронхіальна астма, система детоксикації, ген b2-адренорецептора, поліморфізм, комбінований генотип.Цель. Исследовать ассоциацию полиморфных вариантов генов ферментов первой – CYP1A1 (T6235C) и второй – NAT2 (С481Т, G590A, G857A), GSTM1 («0»), GSTT1 («0») и GSTP1 (A313G) фаз системы детоксикации, а также гена ADRB2 (C79G) с развитием бронхиальной астмы (БА) у детей. Методы. Полиморфные варианты изучали с помощью ПЦР и ПДРФанализа у 86 здоровых индивидов и 114 пациентов с клиническим диагнозом БА. Результаты. Установлена частота полиморфных вариантов генов ферментов первой и второй фаз системы детоксикации, а также гена ADRB2 у больных БА детей и здоровых индивидов. Выводы. Полиморфные варианты генов NAT2 (481Т), GSTP1 (313G) и ADRB2 79G и их комбинации в генотипе чаще наблюдаются среди пациентов с БА по сравнению с контрольной группой, что свидетельствует в пользу их вовлечения в патогенез БА у детей. Ключевые слова: бронхиальная астма, система детоксикации, ген b2-адренорецептора, полиморфизм, комбинированный генотип

Estimation and minimization of the influence of various supporting devices on the integral aerodynamic characteristics of the models of axisymmetric bodies and isolated helicopter fuselages in a low-speed wind tunnel

Estimation and minimization of influence of supporting devices on the aerodynamic characteristics of various bodies during the wind tunnel tests has always attracted considerable attention. The three-dimensional interference of a model and supports is quite complex. It depends on the type of the supporting devices, the character of the flow around the bodies, the angle of attack and the yaw angle. The influence of the suspension system causes the emergence of the systematic measurement errors. Corrections for this influence are especially important for well-streamlined wind-tunnel models (axisymmetric bodies, isolated fuselages of airplanes and modern helicopters.) Systematic experimental investigations were carried out in the wind tunnel of KNRTU-KAI in order to determine the influence of various supporting devices on the aerodynamic characteristics of axisymmetric bodies with different aspect ratios and helicopter fuselage models. The supports drag was minimized with the help of a single-panel suspension system, which was designed at the Aerodynamics department of MAI. This approach allowed to identify the influence of various suspension devices (bottom struts and side support stings) on the integral aerodynamic characteristics of various models. It also helped to estimate the nature (cause) and magnitude of the required corrections

Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters

Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter

Measurement of the inclusive isolated prompt photon cross-section in pp collisions at sqrt(s)= 7 TeV using 35 pb-1 of ATLAS data

A measurement of the differential cross-section for the inclusive production of isolated prompt photons in pp collisions at a center-of-mass energy sqrt(s) = 7 TeV is presented. The measurement covers the pseudorapidity ranges |eta|<1.37 and 1.52<=|eta|<2.37 in the transverse energy range 45<=E_T<400GeV. The results are based on an integrated luminosity of 35 pb-1, collected with the ATLAS detector at the LHC. The yields of the signal photons are measured using a data-driven technique, based on the observed distribution of the hadronic energy in a narrow cone around the photon candidate and the photon selection criteria. The results are compared with next-to-leading order perturbative QCD calculations and found to be in good agreement over four orders of magnitude in cross-section.Comment: 7 pages plus author list (18 pages total), 2 figures, 4 tables, final version published in Physics Letters

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02