Moscow State University

About: Moscow State University is a education organization based out in Moscow, Russia. It is known for research contribution in the topics: Catalysis & Laser. The organization has 66747 authors who have published 123358 publications receiving 1753995 citations. The organization is also known as: MSU & Lomonosov Moscow State University.

Evidence for Collective Multiparticle Correlations in p-Pb Collisions

Abstract: The second-order azimuthal anisotropy Fourier harmonics, v2, are obtained in pPb and PbPb collisions over a wide pseudorapidity (eta) range based on correlations among six or more charged particles. The pPb data, corresponding to an integrated luminosity of 35 inverse nanobarns, were collected during the 2013 LHC pPb run at a nucleon-nucleon center-of-mass energy of 5.02 TeV by the CMS experiment. A sample of semi-peripheral PbPb collision data at sqrt(s[NN])= 2.76 TeV, corresponding to an integrated luminosity of 2.5 inverse microbarns and covering a similar range of particle multiplicities as the pPb data, is also analyzed for comparison. The six- and eight-particle cumulant and the Lee-Yang zeros methods are used to extract the v2 coefficients, extending previous studies of two- and four-particle correlations. For both the pPb and PbPb systems, the v2 values obtained with correlations among more than four particles are consistent with previously published four-particle results. These data support the interpretation of a collective origin for the previously observed long-range (large Delta[eta]) correlations in both systems. The ratios of v2 values corresponding to correlations including different numbers of particles are compared to theoretical predictions that assume a hydrodynamic behavior of a pPb system dominated by fluctuations in the positions of participant nucleons. These results provide new insights into the multi-particle dynamics of collision systems with a very small overlapping region.

The OPERA experiment in the CERN to Gran Sasso neutrino beam

Abstract: The OPERA neutrino oscillation experiment has been designed to prove the appearance of ντ in a nearly pure νμ beam (CNGS) produced at CERN and detected in the underground Hall C of the Gran Sasso Laboratory, 730 km away from the source. In OPERA, τ leptons resulting from the interaction of ντ are produced in target units called bricks made of nuclear emulsion films interleaved with lead plates. The OPERA target contains 150000 of such bricks, for a total mass of 1.25 kton, arranged into walls interleaved with plastic scintillator strips. The detector is split into two identical supermodules, each supermodule containing a target section followed by a magnetic spectrometer for momentum and charge measurement of penetrating particles. Real time information from the scintillators and the spectrometers provide the identification of the bricks where the neutrino interactions occurred. The candidate bricks are extracted from the walls and, after X-ray marking and an exposure to cosmic rays for alignment, their emulsion films are developed and sent to the emulsion scanning laboratories to perform the accurate scan of the event. In this paper, we review the design and construction of the detector and of its related infrastructures, and report on some technical performances of the various components. The construction of the detector started in 2003 and it was completed in Summer 2008. The experiment is presently in the data taking phase. The whole sequence of operations has proven to be successful, from triggering to brick selection, development, scanning and event analysis.

Microbial populations in Antarctic permafrost: biodiversity, state, age, and implication for astrobiology.

Abstract: Antarctic permafrost soils have not received as much geocryological and biological study as has been devoted to the ice sheet, though the permafrost is more stable and older and inhabited by more microbes. This makes these soils potentially more informative and a more significant microbial repository than ice sheets. Due to the stability of the subsurface physicochemical regime, Antarctic permafrost is not an extreme environment but a balanced natural one. Up to 104 viable cells/g, whose age presumably corresponds to the longevity of the permanently frozen state of the sediments, have been isolated from Antarctic permafrost. Along with the microbes, metabolic by-products are preserved. This presumed natural cryopreservation makes it possible to observe what may be the oldest microbial communities on Earth. Here, we describe the Antarctic permafrost habitat and biodiversity and provide a model for martian ecosystems.

High energy density in silver niobate ceramics

Abstract: Solid-state dielectric energy storage is the most attractive and feasible way to store and release high power energy compared to chemical batteries and electrochemical super-capacitors. However, the low energy density (ca. 1 J cm−3) of commercial dielectric capacitors has limited their development. Dielectric materials showing field induced reversible phase transitions have great potential to break the energy storage density bottleneck. In this work, dense AgNbO3 ceramic samples were prepared successfully using solid state methods. Ferroelectric measurements at different temperatures reveal evidence of two kinds of polar regions. One of these is stable up to 70 °C, while the other remains stable up to 170 °C. The associated transition temperatures are supported by second harmonic generation measurements on poled samples and are correlated with the occurrence of two sharp dielectric responses. The average unit cell volume is seen to increase with increasing DC field and has been interpreted in terms of increasing levels of structural disorder in the system. At a high electric field the structure becomes ferroelectric with high polarization. This field induced transition exhibits a recoverable energy density of 2.1 J cm−3, which represents one of the highest known values for lead-free bulk ceramics.

Denaturation capacity: a new quantitative criterion for selection of organic solvents as reaction media in biocatalysis

Abstract: The process of reversible denaturation of several proteins (alpha-chymotrypsin, trypsin, laccase, chymotrypsinogen, cytochrome c and myoglobin) by a broad series of organic solvents of different nature was investigated using both our own and literature data, based on the results of kinetic and spectroscopic measurements. In all systems studied, the denaturation proceeded in a threshold manner, i.e. an abrupt change in catalytic and/or spectroscopic properties of dissolved proteins was observed after a certain threshold concentration of the organic solvent had been reached. To account for the observed features of the denaturation process, a thermodynamic model of the reversible protein denaturation by organic solvents was developed, based on the widely accepted notion that an undisturbed water shell around the protein globule is a prerequisite for the retention of the native state of the protein. The quantitative treatment led to the equation relating the threshold concentration of the organic solvent with its physicochemical characteristics, such as hydrophobicity, solvating ability and molecular geometry. This equation described well the experimental data for all proteins tested. Based on the thermodynamic model of protein denaturation, a novel quantitative parameter characterizing the denaturing strength of organic solvents, called the denaturation capacity (DC), was suggested. Different organic solvents, arranged according to their DC values, form the DC scale of organic solvents which permits theoretical prediction of the threshold concentration of any organic solvent for a given protein. The validity of the DC scale for this kind of prediction was verified for all proteins tested and a large number of organic solvents. The experimental data for a few organic solvents, such as formamide and N-methylformamide, did not comply with equations describing the denaturation model. Such solvents form the group of so-called 'bad' solvents; reasons for the occurrence of 'bad' solvents are not yet clear. The DC scale was further extended to include also highly nonpolar solvents, in order to explain the well-known ability of enzymes to retain catalytic activity and stability in biphasic systems of the type water/water-immiscible organic solvent. It was quantitatively demonstrated that this ability is accounted for by the simple fact that nonpolar solvents are not sufficiently soluble in water to reach the inactivation threshold concentration.