Thermal Renormalons in Scalar Field Theory

In the frame of the scalar theory $g \phi ^{4}$, we explore the occurrence of thermal renormalons, i. e. temperature dependent singularities in the Borel plane. The discussion of a particular renormalon type diagram at finite temperature, using Thermofield Dynamics, allows us to establish that these singularities actually get a temperature dependence. This dependence appears in the residues of the poles, remaining their positions unchanged with temperature.Comment: 12 pages, 3 figures, uses feynMF. Minor correction

Unconventional Anomalous Hall Effect in the Metallic Triangular-Lattice Magnet PdCrO2

We experimentally reveal an unconventional anomalous Hall effect (UAHE) in a quasi-two-dimensional triangular-lattice antiferromagnet PdCrO2. Using high quality single crystals of PdCrO2, we found that the Hall resistivity deviates from the conventional behavior below T* = 20 K, noticeably lower than TN = 37.5 K, at which Cr^{3+} (S=3/2) spins order in a 120 degree structure. In view of the theoretical expectation that the spin chirality cancels out in the simplest 120 degree spin structure, we discuss required conditions for the emergence of UAHE within Berry-phase mechanisms.Comment: 4 pages, 5 figures, accepted for publication in PR

The study of excited oxygen molecule gas species production and quenching on thermal protection system materials

The detection of excited oxygen and ozone molecules formed by surface catalyzed oxygen atom recombination and reaction was investigated by laser induced fluorescence (LIF), molecular beam mass spectrometric (MBMS), and field ionization (FI) techniques. The experiment used partially dissociated oxygen flows from a microwave discharge at pressures in the range from 60 to 400 Pa or from an inductively coupled RF discharge at atmospheric pressure. The catalyst materials investigated were nickel and the reaction cured glass coating used for Space Shuttle reusable surface insulation tiles. Nonradiative loss processes for the laser excited states makes LIF detection of O2 difficult such that formation of excited oxygen molecules could not be detected in the flow from the microwave discharge or in the gaseous products of atom loss on nickel. MBMS experiments showed that ozone was a product of heterogeneous O atom loss on nickel and tile surfaces at low temperatures and that ozone is lost on these materials at elevated temperatures. FI was separately investigated as a method by which excited oxygen molecules may be conveniently detected. Partial O2 dissociation decreases the current produced by FI of the gas

Z-DNA forming regions in the human genome

Z-DNA is the left-handed helical structure of the usually right-handed B-DNA double helix structure. Z-DNA conformations have been found to cause mutagenesis and genetic instability [1]. In this study, human genome sequences potentially forming Z-DNA regions (ZDRs) were extracted and analysed for functional implications

Comment on "Spin Transport properties of the quantum one-dimensional non-linear sigma model"

In a recent preprint (cond-mat/9905415), Fujimoto has used the Bethe ansatz to compute the finite temperature, zero frequency Drude weight of spin transport in the quantum O(3) non-linear sigma model in a magnetic field $H \neq 0$. We show here that, contrary to his claims, the results are in accord with earlier semiclassical results (Sachdev and Damle, cond-mat/9610115). We also comment on his 1/N expansion, and show that it does not properly describe the long-time correlations.Comment: 4 page

Cloud for Gaming

Cloud for Gaming refers to the use of cloud computing technologies to build large-scale gaming infrastructures, with the goal of improving scalability and responsiveness, improve the user's experience and enable new business models.Comment: Encyclopedia of Computer Graphics and Games. Newton Lee (Editor). Springer International Publishing, 2015, ISBN 978-3-319-08234-

Kondo Problem and Related One-Dimensional Quantum Systems: Bethe Ansatz Solution and Boundary Conformal Field Theory

We review some exact results on Kondo impurity systems derived from Bethe-ansatz solutions and boundary conformal field theory with particular emphasis on universal aspects of the phenomenon. The finite-size spectra characterizing the low-energy fixed point are computed from the Bethe-ansatz solutions of various models related to the Kondo problem. Using the finite-size scaling argument, we investigate their exact critical properties. We also discuss that a universal relation between the Kondo effect and the impurity effect in one-dimensional quantum systems usefully expedites our understanding of these different phenomena.Comment: 6 pages, no figure

Kinetic signatures of the region surrounding the X-line in asymmetric (magnetopause) reconnection

Kinetic particle-in-cell simulations are used to identify signatures of the electron diffusion region (EDR) and its surroundings during asymmetric magnetic reconnection. A "shoulder" in the sunward pointing normal electric field (EN > 0) at the reconnection magnetic field reversal is a good indicator of the EDR, and is caused by magnetosheath electron meandering orbits in the vicinity of the x-line. Earthward of the X-line, electrons accelerated by EN form strong currents and crescent-shaped distribution functions in the plane perpendicular to B. Just downstream of the X-line, parallel electric fields create field-aligned crescent electron distribution functions. In the immediate upstream magnetosheath, magnetic field strength, plasma density, and perpendicular electron temperatures are lower than the asymptotic state. In the magnetosphere inflow region, magnetosheath ions intrude resulting in an Earthward pointing electric field and parallel heating of magnetospheric particles. Many of the above properties persist with a guide field of at least unity.Comment: Submitted to Geophysical Research Letter

Isolamento e caracterização de Flavobacterium columnare de tambaqui (Colossoma macropomum).

O objetivo deste estudo foi de realizar o isolamento e a caracterização de Flavobacterium columnare de tambaqui (Colossoma macropomum) criado em tanques escavados na região de Rio Preto da Eva - AM