Stereospecific thionation of 2-ethoxy-1,2-oxaphosphorinane 2-oxide and its derivatives with Lawesson's reagent

The parent phostone, 2-ethoxy-1,2-oxaphosphorinane 2-oxide 1, and derivatives with substituents at the 3-position (methyl, phenyl, and benzyl; compounds 2-4) were convened with Lawesson's reagent to provide the corresponding sulfide analogues 5-8 in moderate yields. The conversion of 2-4 occurred with retention of configuration at the phosphorus center. This was implied from the relative R(f) values and 13C and 31P NMR chemical shifts of the individual isomers and confirmed for the transformation of 3b to 7b by X-ray structures of each of these. Oxidation of 7b, 8a, and 8b with m-chloroperoxybenzoic acid alone led to the corresponding oxides 3b, 4a, and 4b with retention. The presence of trifluoroacetic acid during this oxidation process led to varying degrees of epimerization about phosphorus and was dependent on the relative molar equivalents of this acid

Hydration of a B-DNA Fragment in the Method of Atom-atom Correlation Functions with the Reference Interaction Site Model Approximation

We propose an efficient numerical algorithm for solving integral equations of the theory of liquids in the Reference Interaction Site Model (RISM) approximation for infinitely dilute solution of macromolecules with a large number of atoms. The algorithm is based on applying the nonstationary iterative methods for solving systems of linear algebraic equations. We calculate the solvent-solute atom-atom correlation functions for a fragment of the B-DNA duplex d(GGGGG).d(CCCCC) in infinitely dilute aqueous solution. The obtained results are compared with available experimental data and results from computer simulations.Comment: 9 pages, RevTeX, 9 pages of ps figures, accepted for publications in JC

Negative anisotropy in Fe10Ni90 films

It is shown that in the Fe10Ni90 film the easy magnetization axis can be formed not along the deposition field, as it occurs in the Fe19Ni81 film, but across, that is a "negative anisotropy" effect occurs. A model that qualitatively describes this effect is proposed. Using the Kerr magnetometer, local measurements of the variation of the direction of the easy magnetization axis over the area of the film sample Fe10Ni90 were carried out and compared with the general view of the domain structure. © Published under licence by IOP Publishing Ltd

ПРОГНОЗИРОВАНИЕ РАЗВИТИЯ АВИАСТРОЕНИЯ С ИСПОЛЬЗОВАНИЕМ МЕТОДОВ ФОРСАЙТА: ЗАРУБЕЖНЫЙ ОПЫТ

In the article the forecasts of the aircraft industry made within the framework of international foresight studies of the last decade are discussed. The objectives, scope, topics and level of detail of these projects are defined. Comparative analysis of foresight studies of the EU, Canada, France, USA, Australia, Japan, Korea, India and Russia allows to create a collective "Image of the Future" of the global aircraft industry, reflecting the wide range of customers needs and expectations.In the twenty-first century foresight became an instrument of public policy building in developed countries. The foresight studies for aviation sector demonstrate noticeable differences: some of them are dedicated to the prospects of aircraft industry as a whole, others are studying special issues such as aviation safety. Most part of modern foresight projects consider the aviation prospects within the context of global challenges, environmental, energy and technological trends (development of new materials, intelligent technology, etc).Technologies considered by leading foresight projects are grouped into 10 thematic areas: aircraft design; aircraft engines; new materials, methods of their creation and development; avionics; information and communication technologies; ecology and environment protection; energy saving; ground operations (including operation of airports); aviation security; air traffic management. Despite the existing differences of sectoral goal-setting, some sustainable priorities were found. Among them there are three technological groups: technologies improving ecological performance and reducing harmful emissions; development of new materials and coatings for the aviation industry; the improvement of aviation safety.The performed analysis of aviation foresight results has shown the importance of strengthening international cooperation in the area of ecology, in particular the harmonization of environment protection requirements, of multidisciplinary approach to forecasting; orientation to the concept of "Grand Challenges", which provides for the transition from separate technology areas support to the search of complex solutions of the problems facing the world community. Какие самолеты будут востребованы через 20-40 лет? Какие угрозы и технологические прорывы ожидаются в будущем? Достаточно ли открыты возможности для достижения намеченных целей? На эти и иные вопросы стремятся дать ответ в прогнозных исследованиях ученые всего мира, используя традиционные и инновационные подходы, в том числе современные методики анализа больших данных и экспертной информации. Методология форсайта, сочетающая методы качественной оценки и количественных измерений, позволила создать собирательный «образ будущего» авиастроения, объединяющий широкий спектр потребностей и ожиданий людей всего мира

Measurement of the B0_s semileptonic branching ratio to an orbitally excited D_s** state, Br(B0_s -> Ds1(2536) mu nu)

In a data sample of approximately 1.3 fb-1 collected with the D0 detector between 2002 and 2006, the orbitally excited charm state D_s1(2536) has been observed with a measured mass of 2535.7 +/- 0.6 (stat) +/- 0.5 (syst) MeV via the decay mode B0_s -> D_s1(2536) mu nu X. A first measurement is made of the branching ratio product Br(b(bar) -> D_s1(2536) mu nu X).Br(D_s1(2536)->D* K0_S). Assuming that D_s1(2536) production in semileptonic decay is entirely from B0_s, an extraction of the semileptonic branching ratio Br(B0_s -> D_s1(2536) mu nu X) is made.Comment: 7 pages, 2 figures, LaTeX, version with minor changes as accepted by Phys. Rev. Let

Measurements of differential cross sections of Z/gamma*+jets+X events in proton anti-proton collisions at sqrt{s}=1.96 TeV

We present cross section measurements for Z/gamma*+jets+X production, differential in the transverse momenta of the three leading jets. The data sample was collected with the D0 detector at the Fermilab Tevatron proton anti-proton collider at a center-of-mass energy of 1.96 TeV and corresponds to an integrated luminosity of 1 fb-1. Leading and next-to-leading order perturbative QCD predictions are compared with the measurements, and agreement is found within the theoretical and experimental uncertainties. We also make comparisons with the predictions of four event generators. Two parton-shower-based generators show significant shape and normalization differences with respect to the data. In contrast, two generators combining tree-level matrix elements with a parton shower give a reasonable description of the the shapes observed in data, but the predicted normalizations show significant differences with respect to the data, reflecting large scale uncertainties. For specific choices of scales, the normalizations for either generator can be made to agree with the measurements.Comment: Published in PLB. 11 pages, 3 figure

Measurement of the t-channel single top quark production cross section

The D0 collaboration reports direct evidence for electroweak production of single top quarks through the t-channel exchange of a virtual W boson. This is the first analysis to isolate an individual single top quark production channel. We select events containing an isolated electron or muon, missing transverse energy, and two, three or four jets from 2.3 fb^-1 of ppbar collisions at the Fermilab Tevatron Collider. One or two of the jets are identified as containing a b hadron. We combine three multivariate techniques optimized for the t-channel process to measure the t- and s-channel cross sections simultaneously. We measure cross sections of 3.14 +0.94 -0.80 pb for the t-channel and 1.05 +-0.81 pb for the s-channel. The measured t-channel result is found to have a significance of 4.8 standard deviations and is consistent with the standard model prediction.Comment: 7 pages, 6 figure

Simultaneous measurement of the ratio B(t->Wb)/B(t->Wq) and the top quark pair production cross section with the D0 detector at sqrt(s)=1.96 TeV

We present the first simultaneous measurement of the ratio of branching fractions, R=B(t->Wb)/B(t->Wq), with q being a d, s, or b quark, and the top quark pair production cross section sigma_ttbar in the lepton plus jets channel using 0.9 fb-1 of ppbar collision data at sqrt(s)=1.96 TeV collected with the D0 detector. We extract R and sigma_ttbar by analyzing samples of events with 0, 1 and >= 2 identified b jets. We measure R = 0.97 +0.09-0.08 (stat+syst) and sigma_ttbar = 8.18 +0.90-0.84 (stat+syst)} +/-0.50 (lumi) pb, in agreement with the standard model prediction.Comment: submitted to Phys.Rev.Letter