Sofia University

About: Sofia University is a education organization based out in Sofia, Bulgaria. It is known for research contribution in the topics: Large Hadron Collider & Standard Model. The organization has 8533 authors who have published 15730 publications receiving 306320 citations. The organization is also known as: University of Sofia & BFUS.

Alarmin high-mobility group B1 (HMGB1) is regulated in human adipocytes in insulin resistance and influences insulin secretion in β-cells.

Abstract: Alarmin high-mobility group B1 (HMGB1) is regulated in human adipocytes in insulin resistance and influences insulin secretion in β-cells

LOOKING FOR A PULSE: A SEARCH FOR ROTATIONALLY MODULATED RADIO EMISSION FROM THE HOT JUPITER, τ BOÖTIS b

Abstract: Hot Jupiters have been proposed as a likely population of low-frequency radio sources due to electron cyclotron maser emission of similar nature to that detected from the auroral regions of magnetized solar system planets. Such emission will likely be confined to specific ranges of orbital/rotational phase due to a narrowly beamed radiation pattern. We report on GMRT 150 MHz radio observations of the hot Jupiter τ Bootis b, consisting of 40 hr carefully scheduled to maximize coverage of the planet's 79.5 hr orbital/rotational period in an effort to detect such rotationally modulated emission. The resulting image is the deepest yet published at these frequencies and leads to a 3σ upper limit on the flux density from the planet of 1.2 mJy, two orders of magnitude lower than predictions derived from scaling laws based on solar system planetary radio emission. This represents the most stringent upper limits for both quiescent and rotationally modulated radio emission from a hot Jupiter yet achieved and suggests that either (1) the magnetic dipole moment of τ Bootis b is insufficient to generate the surface field strengths of >50 G required for detection at 150 MHz or (2) Earth lies outside the beaming pattern of the radio emission from the planet.

Effects of deposited Pt particles on the reducibility of CeO2(111)

Abstract: The interaction of Pt particles with the regular CeO2(111) surface has been studied using Pt8 clusters as representative examples. The atomic and electronic structure of the resulting model systems have been obtained through periodic spin-polarized density functional calculations using the PW91 exchange-correlation potential corrected with the inclusion of a Hubbard U parameter. The focus is on the effect of the metal–support interaction on the surface reducibility of ceria. Several initial geometries and orientations of Pt8 with respect to the ceria substrate have been explored. It has been found that deposition of Pt8 over the ceria surface results in spontaneous oxidation of the supported particle with a concomitant reduction of up to two Ce4+ cations to Ce3+. Oxygen vacancy formation on the CeO2(111) surface and oxygen spillover to the adsorbed particle have also been considered. The presence of the supported Pt8 particles has a rather small effect (∼0.2 eV) on the O vacancy formation energy. However, it is predicted that the spillover of atomic oxygen from the substrate to the metal particle greatly facilitates the formation of oxygen vacancies: the calculated energy required to transfer an oxygen atom from the CeO2(111) surface to the supported Pt8 particle is only 1.00 eV, i.e. considerably smaller than 2.25 eV necessary to form an oxygen vacancy on the bare regular ceria surface. This strongly suggests that the propensity of ceria systems to store and release oxygen is directly affected by the presence of supported Pt particles.

Shape, transverse size, and charged-hadron multiplicity of jets in pp collisions at √s = 7 TeV

Abstract: Measurements of jet characteristics from inclusive jet production in proton-proton collisions at a centre-of-mass energy of 7 TeV are presented. The data sample was collected with the CMS detector at the LHC during 2010 and corresponds to an integrated luminosity of 36 inverse picobarns. The mean charged hadron multiplicity, the differential and integral jet shape distributions, and two independent moments of the shape distributions are measured as functions of the jet transverse momentum for jets reconstructed with the anti-kT algorithm. The measured observables are corrected to the particle level and compared with predictions from various QCD Monte Carlo generators.