Periodic changes in the state of a 4f metal compound under pressure

The statement is proved that in the framework of experimentally achievable pressure the existing compounds containing rare-earths can be characterized as those belonging to one of the three states depending on distance RE-O: an electronic state, a vibronic state, in particular a state of electronic-vibronic equilibrium, and a semiconductor-metal state. The hypothesis is put forward that the mechanism of realization of superconducting state in PrBa₂Cu₃O₆.₆ can be considereОбосновывается утверждение, что в рамках экспериментально достижимого давления существующие соединения, содержащие редкие земли, могут быть охарактеризованы принадлежностью к одному из трех состояний в зависимости от расстояния RЕ–O: электронному, вибронному (в частности, состоянию электрон-вибронного равновесия) и полупроводниково-металлическому. Выдвигается гипотеза, что механизм реализации сверхпроводящего состояния в PrBa₂Cu₃O₆.₆ можно рассматривать как изменение соотношения полупроводниковой и металлической проводимостей в веществе.Обґрунтовується твердження, що в рамках тиску, який можна експериментально досягти, iснуючі з’єднання, що містять рідкісні землі, можуть бути охарактеризовані належністю до одного з трьох станів залежно від відстані RE–O: електронного, вібронного (зокрема, стан електрон-вібронної рівноваги) та напівпровідниково-металічного. Висувається гіпотеза, що механізм реалізації надпровідного стану в PrBa₂Cu₃O₆.₆ можна розглядати як зміну співвідношення напівпровідникової та металічної провідностей у речовині

Программированные роды у женщин с оперированной маткой

The paper deals with the problems of programmed delivery in women with a uterine scar. The study included 144 pregnant women with a uterus operated who started to give birth vaginally (per vias naturales). The conditions for induction, analyze the clinical efficacy of different methods of induction were assessed. 134 women given birth successfully, programmed delivery were conducted in 84 patients. There were 3 ruptures of the uterus.Статья посвящена проблемам программированных родов у женщин с «рубцом на матке». В исследовании участвовали 144 беременных с оперированной маткой, начавших рожать per vias naturales. Проведена оценка условий для родовозбуждения, проанализирована клиническая эффективность различных методов индукции родов. Успешно проведены влагалищные роды у 134 пациенток, у 84 — программированные роды. В группе программированных родов произошел один разрыв матки

Optimization of use conditions for cathodic arc nickel coating doped with phosphorus

The results of tribological tests for a cathodic arc nickel coating doped with phosphorus are presented. The coating (thickness of 2 μm) is applied by a vacuum arc method from a nickel target with 6% phosphorus. The friction coefficient (Cfᵣ) was determined on the tribometer, the depth of wear h of the coating after tribological tests was determined by the contact profilometry method, and the specific volumetric wear (ω) was calculated. The obtained values of Cfᵣ, ω, and h were used to optimize the parameters of tribological tests (load and slip frequency).Представлено результати триботехнічних випробувань катодно-дугового нікелевого покриття, легованого фосфором. Покриття товщиною 2 мкм нанесено катодно-дуговим методом з нікелевої мішені з 6% фосфору. На трибометрі визначені коефіцієнти тертя (kтр), методом контактної профілометрії визначена глибина зносу (h) покриття після триботехнічних випробувань, розрахований питомий об'ємний знос (ω). За отриманими значеннями kтр, ω та h проведена оптимізація параметрів триботехнічних випробувань: навантаження та частоти ковзання.Представлены результаты триботехнических испытаний катодно-дугового никелевого покрытия, легированного фосфором. Покрытие толщиной 2 мкм нанесено вакуумно-дуговым методом из никелевой мишени с 6% фосфора. На трибометре определены коэффициенты трения (kтр), методом контактной профилометрии определена глубина износа (h) покрытия после триботехнических испытаний, рассчитан удельный объемный износ (ω). По полученным значениям kтр, ω и h проведена оптимизация параметров триботехнических испытаний: нагрузки и частоты скольжения

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

Reducing heterotic M-theory to five dimensional supergravity on a manifold with boundary

This paper constructs the reduction of heterotic $M$-theory in eleven dimensions to a supergravity model on a manifold with boundary in five dimensions using a Calabi-Yau three-fold. New results are presented for the boundary terms in the action and for the boundary conditions on the bulk fields. Some general features of dualisation on a manifold with boundary are used to explain the origin of some topological terms in the action. The effect of gaugino condensation on the fermion boundary conditions leads to a `twist' in the chirality of the gravitino which can provide an uplifting mechanism in the vacuum energy to cancel the cosmological constant after moduli stabilisation.Comment: 16 pages, RevTe

Measurement of D*+/- meson production in jets from pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

This paper reports a measurement of D*+/- meson production in jets from proton-proton collisions at a center-of-mass energy of sqrt(s) = 7 TeV at the CERN Large Hadron Collider. The measurement is based on a data sample recorded with the ATLAS detector with an integrated luminosity of 0.30 pb^-1 for jets with transverse momentum between 25 and 70 GeV in the pseudorapidity range |eta| < 2.5. D*+/- mesons found in jets are fully reconstructed in the decay chain: D*+ -> D0pi+, D0 -> K-pi+, and its charge conjugate. The production rate is found to be N(D*+/-)/N(jet) = 0.025 +/- 0.001(stat.) +/- 0.004(syst.) for D*+/- mesons that carry a fraction z of the jet momentum in the range 0.3 < z < 1. Monte Carlo predictions fail to describe the data at small values of z, and this is most marked at low jet transverse momentum.Comment: 10 pages plus author list (22 pages total), 5 figures, 1 table, matches published version in Physical Review

Search for scalar top quark pair production in natural gauge mediated supersymmetry models with the ATLAS detector in pp collisions at sqrt(s) = 7 TeV

The results of a search for pair production of the lighter scalar partners of top quarks in 2.05 fb-1 of pp collisions at sqrt(s) =7 TeV using the ATLAS experiment at the LHC are reported. Scalar top quarks are searched for in events with two same flavour opposite-sign leptons (electrons or muons) with invariant mass consistent with the Z boson mass, large missing transverse momentum and jets in the final state. At least one of the jets is identified as originating from a b-quark. No excess over Standard Model expectations is found. The results are interpreted in the framework of R-parity conserving, gauge mediated Supersymmetry breaking `natural' scenarios, where the neutralino is the next-to-lightest supersymmetric particle. Scalar top quark masses up to 310 GeV are excluded for the lightest neutralino mass between 115 GeV and 230 GeV at 95% confidence level, reaching an exclusion of the scalar top quark mass of 330 GeV for the lightest neutralino mass of 190 GeV. Scalar top quark masses below 240 GeV are excluded for all values of the lightest neutralino mass above the Z boson mass.Comment: 7 pages plus author list (20 pages total), 4 figures, 1 table, matches published PLB versio