Temperature-dependent magnetospectroscopy of HgTe quantum wells

We report on magnetospectroscopy of HgTe quantum wells in magnetic fields up to 45 T in temperature range from 4.2 K up to 185 K. We observe intra- and inter-band transitions from zero-mode Landau levels, which split from the bottom conduction and upper valence subbands, and merge under the applied magnetic field. To describe experimental results, realistic temperature-dependent calculations of Landau levels have been performed. We show that although our samples are topological insulators at low temperatures only, the signature of such phase persists in optical transitions at high temperatures and high magnetic fields. Our results demonstrate that temperature-dependent magnetospectroscopy is a powerful tool to discriminate trivial and topological insulator phases in HgTe quantum wells

Формирование группы риска по врожденной патологии плода с использованием искусственных нейронных сетей

The aim of the study is the evaluation of the significance of various risk factors for congenital fetus pathology (congenital defect – CD) and the development of risk numeric scale. 424 pregnant women with fetus CD and 520 pregnant women with fetus without congenital defects have been examined. Artificial neural nets have been used for investigation how various factors effect on pregnancy termination. It has been found that the important factors for congenital fetus defect risk are: age younger 18 years of an pregnant women, age older 35 years, noncarring of pregnancy in anamnesis, complicated clinical course of the first pregnancy trimester, CD cases in a family, ultrasonic markers of chromosome pathology in the first pregnancy trimester. Changes in maternal serum AFP, hCG and uE3 levels and blood flow disorders are important to forming high risk group. A numeric scale for CD risk has been developed on the basis of neuronic net analysis.Цель данного исследования — оценка значимости различных факторов риска рождения ребенка с врожденным пороком развития (ВПР) и разработка балльной шкалы риска. Обследованы 424 беременные женщины с ВПР плода и 520 женщин, беременность у которых закончилась рождением ребенка без ВПР. Для исследования влияния различных факторов на исход беременности использовались искусственные нейронные сети. Выявлено, что возраст беременной моложе 18 лет, возраст старше 35 лет, невынашивание в анамнезе, осложненное течение I триместра беременности, наличие случаев врожденной патологии в семье, ультразвуковые маркеры хромосомной патологии в I триместре беременности являются значимыми факторами риска рождения ребенка с ВПР. В формировании группы высокого риска по ВПР большое значение имеет изменение уровней альфафетопротеина (АФП), хорионического гонадотропина (ХГ), эстриола, а также выявленные при допплерометрии гемодинамические нарушения. На основании нейросетевого анализа разработана балльная шкала риска рождения ребенка с ВПР

MAGNETODYNAMIC PROPERTIES OF SPATIALLY DISTRIBUTED FILMS ON THE BASIS OF THE METAL-DIELECTRIC COMPOSITE

In this paper, in the frequency range from 270 MHz to 10 GHz, were investigated the frequency dependences of the absorption coefficient of electromagnetic radiation and frequency dependences of the complex magnetic permeability of the fiberglass which were made of fiberglass with a heterogeneous film deposited on the surface.Работа выполнена при поддержке гранта РФФИ № 16-45-360483 р_а и министерства образования и науки в рамках проектной части государственного задания

New national and regional bryophyte records, 59

Peer reviewe

Observation of the Decay Λ0b→Λ+cτ−¯ν

The first observation of the semileptonic b-baryon decay Λb0→Λc+τ-ν¯τ, with a significance of 6.1σ, is reported using a data sample corresponding to 3 fb-1 of integrated luminosity, collected by the LHCb experiment at center-of-mass energies of 7 and 8 TeV at the LHC. The τ- lepton is reconstructed in the hadronic decay to three charged pions. The ratio K=B(Λb0→Λc+τ-ν¯τ)/B(Λb0→Λc+π-π+π-) is measured to be 2.46±0.27±0.40, where the first uncertainty is statistical and the second systematic. The branching fraction B(Λb0→Λc+τ-ν¯τ)=(1.50±0.16±0.25±0.23)% is obtained, where the third uncertainty is from the external branching fraction of the normalization channel Λb0→Λc+π-π+π-. The ratio of semileptonic branching fractions R(Λc+)B(Λb0→Λc+τ-ν¯τ)/B(Λb0→Λc+μ-ν¯μ) is derived to be 0.242±0.026±0.040±0.059, where the external branching fraction uncertainty from the channel Λb0→Λc+μ-ν¯μ contributes to the last term. This result is in agreement with the standard model prediction

Search for resonances in the mass spectrum of muon pairs produced in association with b quark jets in proton-proton collisions at root 8 and 13 TeV

A search for resonances in the mass range 12-70 GeV produced in association with a b quark jet and a second jet, and decaying to a muon pair, is reported. The analysis is based on data from proton-proton collisions at center-of-mass energies of 8 and 13 TeV, collected with the CMS detector at the LHC and corresponding to integrated luminosities of 19.7 and 35.9 fb(-1), respectively. The search is carried out in two mutually exclusive event categories. Events in the first category are required to have a b quark jet in the central region (|| 2.4) and at least one jet in the forward region (|| > 2.4). Events in the second category are required to have two jets in the central region, at least one of which is identified as a b quark jet, no jets in the forward region, and low missing transverse momentum. An excess of events above the background near a dimuon mass of 28 GeV is observed in the 8 TeV data, corresponding to local significances of 4.2 and 2.9 standard deviations for the first and second event categories, respectively. A similar analysis conducted with the 13 TeV data results in a mild excess over the background in the first event category corresponding to a local significance of 2.0 standard deviations, while the second category results in a 1.4 standard deviation deficit. The fiducial cross section measurements and 95% confidence level upper limits on those for a resonance consistent with the 8 TeV excess are provided at both collision energies