Cosmological Consequences of QCD Phase Transition(s) in Early Universe

We discuss the cosmological consequences of QCD phase transition(s) on the early universe. We argue that our recent knowledge about the transport properties of quark-gluon plasma (QGP) should throw additional lights on the actual time evolution of our universe. Understanding the nature of QCD phase transition(s), which can be studied in lattice gauge theory and verified in heavy ion experiments, provides an explanation for cosmological phenomenon stem from early universe.Comment: 8 pages, 2 eps figure

Effects of suprathermal electrons on the proton temperature anisotropy in space plasmas: Electromagnetic ion-cyclotron instability

In collision-poor plasmas from space, e.g., the solar wind and planetary magnetospheres, the kinetic anisotropy of the plasma particles is expected to be regulated by the kinetic instabilities. Driven by an excess of ion (proton) temperature perpendicular to the magnetic field $(~T_\perp >T_\parallel)$, the electromagnetic ion-cyclotron (EMIC) instability is fast enough to constrain the proton anisotropy, but the observations do not conform to the instability thresholds predicted by the standard theory for bi-Maxwellian models of the plasma particles. This paper presents an extended investigation of the EMIC instability in the presence of suprathermal electrons which are ubiquitous in these environments. The analysis is based on the kinetic (Vlasov-Maxwell) theory assuming that both species, protons and electrons, may be anisotropic, and the EMIC unstable solutions are derived numerically providing an accurate description for conditions typically encountered in space plasmas. The effects of suprathermal populations are triggered by the electron anisotropy and the temperature contrast between electrons and protons. For certain conditions the anisotropy thresholds exceed the limits of the proton anisotropy measured in the solar wind considerably restraining the unstable regimes of the EMIC modes.Comment: Accepted for publication in Astrophysics and space scienc

Seven naphtho-γ-pyrones from the marine-derived fungus Alternaria alternata: structure elucidation and biological properties

Eight bioactive pyrone derivatives were identified from the culture of Alternaria alternata strain D2006, isolated from the marine soft coral Denderonephthya hemprichi, which was selected as its profound antimicrobial activities. The compounds were assigned as pyrophen (1), rubrofusarin B (2), fonsecin (3), and fonsecin B (5) beside to the four dimeric naphtho-γ-pyrones; aurasperone A (6), aurasperone B (7), aurasperone C (8), and aurasperone F (9). Structures of the isolated compounds were identified on the basis of 1D and 2D NMR spectroscopy and mass (EI, ESI, HRESI) data, and by comparison with the literature. Configuration of the four dimeric naphtho-γ-pyrones 6-9 was analyzed by CD spectra, exhibiting an identical stereochemistry

The General Solution for a linear Second Order Homogenous Differential Equations with Variable Coefficients

Abstract : The main goal in this work to find the general solution for some kind of linear second order homogenous differential equations with variable coefficients which have the general form , by using the substitution ,which transform form the above equation to Riccati equation

The Enigma of the Dark Matter

One of the great scientific enigmas still unsolved, the existence of dark matter, is reviewed. Simple gravitational arguments imply that most of the mass in the Universe, at least 90%, is some (unknown) non-luminous matter. Some particle candidates for dark matter are discussed with particular emphasis on the neutralino, a particle predicted by the supersymmetric extension of the Standard Model of particle physics. Experiments searching for these relic particles, carried out by many groups around the world, are also discussed. These experiments are becoming more sensitive every year and in fact one of the collaborations claims that the first direct evidence for dark matter has already been observed.Comment: Invited review article for the journal Contemporary Physics. The level is suitable for researchers which are non-specialists in the subject, and also for students. Latex, 20 pages, 5 figure

Evaluation of red-light camera enforcement using traffic violations

The State of Qatar started to use red-light cameras in 2007 at key signalized intersections and the rate of installation has subsequently increased. In 2017, 19.2% of signalized intersections are equipped with red-light cameras. In many cases, the cameras are not installed on all approaches to the intersections. The purpose of this study is to compare the red-light running violations on approaches with and without red-light running enforcement cameras at the same intersections. Actual field observations were used in this study. Different variables were investigated, including the day of the week, time of day, traffic volume, the possibility of glare on an approach, and the lengths of the yellow and all-red times. A regression tree model was used to explain the characteristics associated with the violations. The results showed that the number of violations on low-volume approaches was five times higher than on high-volume approaches. The results also showed that the presence of the cameras significantly lowered red-light running violations. High-volume approaches without cameras had an approximately eight times higher rate of violations than high-volume approaches with cameras. The analysis also showed that bringing the all-red interval closer to the values recommended by the Institute of Transportation Engineers formula may bring down the rates of violations for low-volume approaches. As with any observational data mining method, the study could benefit from a larger sample size. The method used in the study was effective and is easily transferable to other locations. The results of this study can be used in developing new strategies to improve safety at signalized intersections. 2018 The AuthorsScopu

QFT results for neutrino oscillations and New Physics

The CP asymmetry in neutrino oscillations, assuming new physics at production and/or detection processes, is analyzed. We compute this CP asymmetry using the standard quantum field theory within a general new physics scenario that may generate new sources of CP and flavor violation. Well known results for the CP asymmetry are reproduced in the case of V -A operators, and additional contributions from new physics operators are derived. We apply this formalism to SUSY extensions of the Standard Model where the contributions from new operators could produce a CP asymmetry observable in the next generation of neutrino experiments.Comment: 6 pages, 3 figures, version to be published in Phys.Rev.