Photon and neutral pion production in pp and Pb-Pb collisions at LHC energies in the ALICE experiment

We present the results for direct photon and neutral pion production obtained from proton-proton and lead-lead collisions in the ALICE experiment. Measurement of neutral pions in pp collisions allows to test the validity of QCD-inspired models. The study of neutral pion yields in Pb-Pb collisions permits to study the medium-induced suppression relative to the pp case. The yield of direct photons is compared to perturbative QCD calculations. In the case of central Pb-Pb collisions the observed excess of photons below 4 GeV/c is used to find the effective temperature of the matter.Comment: Talk presented at LISHEP 2015, 14 pages, 15 figure

The Impact of Russian Educational Policy on the Formation of Georgian Education System

The study examined the impact of Russian educational policy on the development of the education system in Georgia. It determines the factors influencing formation of the Georgian educational system for centuries under Tsarist and Soviet Russia. Despite years of reforms since independence, the issue of reorganizing the Georgian education system and eliminating the legacy of the past has not lost its relevance in the current period. The historical research method was used in order to study, analyze and draw specific conclusions from past events. The article presents the four main periods of Tsarist Russia and the first independent republic of Georgia in 1918-1921, the Soviet Union and modern independent Georgia. The mentioned periods were examined in the four main directions - the importance of education, national language policy, management system and teaching-learning approaches. The research has found that tsarist and Soviet authorities used similarly totalitarian-authoritarian methods to achieve imperial or Soviet party goals. An important difference concerned the importance of education when, unlike the Tsarist one, the Soviet authorities imposed a large mission on education, but in return demanded the existence of an ideologized society. As for the first independent republic of Georgia of 1918-1921 and the educational policy of modern independent Georgia, the educational policies of the mentioned periods coincide in regard of Western values, democratic principles and European approaches to teaching and learning. The educational policy of independent Georgia was characterized by a radical nature aimed at liberating the old school traditions and integrating them into the international educational space

Massive Dirac fermions and the zero field quantum Hall effect

Through an explicit calculation for a Lagrangian in quantum electrodynamics in (2+1)-space--time dimensions (QED$_3$), making use of the relativistic Kubo formula, we demonstrate that the filling factor accompanying the quantized electrical conductivity for massive Dirac fermions of a single species in two spatial dimensions is a half (in natural units) when time reversal and parity symmetries of the Lagrangian are explicitly broken by the fermion mass term. We then discuss the most general form of the QED$_3$ Lagrangian, both for irreducible and reducible representations of the Dirac matrices in the plane, with emphasis on the appearance of a Chern-Simons term. We also identify the value of the filling factor with a zero field quantum Hall effect (QHE).Comment: 15 pages. Accepted in Jour. Phys.

Disorder and Confinement Effects to Tune the Optical Properties of Amino Acid Doped Cu2O Crystals

Biominerals are organic-inorganic nanocomposites exhibiting remarkable properties due to their unique configuration. Using optical spectroscopy and theoretical modeling, it is shown that the optical properties of a model bioinspired system, an inorganic semiconductor host (Cu2O) grown in the presence of amino acids (AAs), are strongly influenced by the latter. The absorption and photoluminescence excitation spectra of Cu2O-AAs blue-shift with growing AA content, indicating band gap widening. This is attributed to the void-induced quantum confinement effects. Surprisingly, no such shift occurs in the emission spectra. The theoretical model, assuming an inhomogeneous AA distribution within Cu2O-AAs due to compositional disorder, explains the deviating behavior of the photoluminescence. The model predicts that the potential causing the confinement effects becomes a function of the local AA density. It results in a Gaussian band gap distribution that shapes the optical properties of Cu2O-AAs. Imitating and harnessing the process of biomineralization can pave the way toward new functional materials

Plants and Microorganisms for Phytoremediation of Soils Polluted with Organochlorine Pesticides

The goal of presented work is the development phytoremediation method targeted to cleaning environment polluted with organochlorine pesticides, based on joint application of plants and microorganisms. For this aim the selection of plants and microorganisms with corresponding capabilities towards three organochlorine pesticides (Lindane, DDT and PCP) has been carried out. The tolerance of plants to tested pesticides and induction degree of plant detoxification enzymes by these compounds have been used as main criteria for estimating the applicability of plants in proposed technology. Obtained results show that alfalfa, maize and soybean among tested six plant species have highest tolerance to pesticides. As a result of screening, more than 30 strains from genera Pseudomonas have been selected. As a result of GC analysis of incubation area, 11 active cultures for investigated pesticides are carefully chosen