Event-by-Event Fluctuations of Particle Ratios in Heavy-Ion Collisions

We study event-by-event dynamical fluctuations of various particle ratios at different energies. We assume that particle production in final state is due to chemical equilibrium processes. We compare results from resonance gas model with available experimental data. At SPS energies, the model can very well reproduce the experimentally measured fluctuations. We make predictions for dynamical fluctuations of strangeness and non-strangeness particle ratios. We found that the energy-dependence is non-monotonic. Furthermore, we found that fluctuations strongly depend on particle ratios.Comment: 6 pages, 2 figure, 1 tabl

Matter-Antimatter Asymmetry in the Large Hadron Collider

The matter-antimatter asymmetry is one of the greatest challenges in the modern physics. The universe including this paper and even the reader him(her)self seems to be built up of ordinary matter only. Theoretically, the well-known Sakharov's conditions remain the solid framework explaining the circumstances that matter became dominant against the antimatter while the universe cools down and/or expands. On the other hand, the standard model for elementary particles apparently prevents at least two conditions out of them. In this work, we introduce a systematic study of the antiparticle-to-particle ratios measured in various $NN$ and $AA$ collisions over the last three decades. It is obvious that the available experimental facilities turn to be able to perform nuclear collisions, in which the matter-antimatter asymmetry raises from $\sim 0$ at AGS to $\sim 100$ at LHC. Assuming that the final state of hadronization in the nuclear collisions takes place along the freezeout line, which is defined by a constant entropy density, various antiparticle-to-particle ratios are studied in framework of the hadron resonance gas (HRG) model. Implementing modified phase space and distribution function in the grand-canonical ensemble and taking into account the experimental acceptance, the ratios of antiparticle-to-particle over the whole range of center-of-mass-energies are very well reproduced by the HRG model. Furthermore, the antiproton-to-proton ratios measured by ALICE in $pp$ collisions is also very well described by the HRG model. It is likely to conclude that the LHC heavy-ion program will produce the same particle ratios as the $pp$ program implying the dynamics and evolution of the system would not depend on the initial conditions. The ratios of bosons and baryons get very close to unity indicating that the matter-antimatter asymmetry nearly vanishes at LHC.Comment: 9 pages, 5 eps-figures, revtex4-styl

Fluctuations of Particle Yield Ratios in Heavy-Ion Collisions

We study the dynamical fluctuations of various particle yield ratios at different incident energies. Assuming that the particle production yields in the hydronic final state are due to equilibrium chemical processes ($\gamma=1$), the experimental results available so far are compared with the hadron resonance gas model (HRG) taking into account the limited momentum acceptance in heavy-ion collisions experiments. Degenerated light and conserved strange quarks are presumed at all incident energies. At the SPS energies, the HRG with $\gamma=1$ provides a good description for the measured dynamical fluctuations in $(K^++K^-)/(\pi^++\pi^-)$. To reproduce the RHIC results, $\gamma$ should be larger than one. We also studied the dynamical fluctuations of $(p+\bar{p})/(\pi^++\pi^-)$. It is obvious that the energy-dependence of these dynamical fluctuations is non-monotonic.Comment: 8 pages, 2 eps figures and 1 tabl

The Effects of Quantum Entropy on the Bag Constant

The effects of quantum entropy on the bag constant are studied at low temperatures and small chemical potentials. The inclusion of the quantum entropy of the quarks in the equation of state provides the hadronic bag with an additional heat which causes a decrease in the effective latent heat inside the bag. We have considered two types of baryonic bags, $\Delta$ and $\Omega^-$. In both cases we have found that the bag constant without the quantum entropy almost does not change with the temperature and the quark chemical potential. The contribution from the quantum entropy to the equation of state clearly decreases the value of the bag constant.Comment: 7 pages, 2 figures (two parts each

Curcumin protection activities against γ-Rays-induced molecular and biochemical lesions

BACKGROUND: Curcumin is a yellow-pigment phenolic compound used as a food spice and has a broad spectrum of antioxidant, anti-carcinogenic, anti-mutagenic and anti-inflammatory properties. METHODS: Radio-protective efficacy of curcumin; diferuloylmethane (C(21)H(20)O(6)) was evaluated using molecular and biochemical assays in male mice after exposure to 3 Gy γ-rays. Curcumin was given at a dose of 400 μmol/ kg body weight via gastric tubes for 5 following days either pre-, post- or both pre- and post-exposure. RESULTS: The incidence of aberrant cells and aberration types (mostly chromatids, breaks and fragments) was reduced with curcumin dosage as compared to irradiated group. Thiobarbituric acid reactive substances (TBARS), hydroperoxide (HP), xanthine oxidase (XO) and apoptotic markers (DNA- fragmentation and caspase-3 activation) were increased significantly, whereas levels of glutathione (GSH) and the enzymatic antioxidants [Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)] were significantly depleted in γ-irradiated mice. Curcumin treatments of mice groups including the 5 days pre-irradiation treated group (protected), the 5 days post-irradiation treated group (treated), and the curcumin treated group 5 days pre- and post-irradiation (protracted), have attenuated the liver toxic effects of γ-rays as manifested by reducing the levels of TBARS, HP, XO and DNA fragmentation. Curcumin has also rescued the depletion of GSH and the enzymatic-antioxidant status. CONCLUSIONS: Curcumin has significant radio-protective and radio-recovery activities in γ-irradiated mice. It has antioxidant potential against γ-rays-induced cytogenetic, molecular and biochemical lesions in mice

The impact of metabolic syndrome on the clinical profile and tumor characteristics of endometrial carcinoma

Background: The objective is to study the influence of different components of metabolic syndrome on clinical behavior and tumor characteristics of endometrial cancer cases and to evaluate if metformin usage affects the stage and grade of endometrial cancer.Methods: 60 women attending the gynecological oncology clinic at El Shatby Maternity University Hospital, after being diagnosed as endometrial carcinoma, were recruited in the study. Serum samples were collected to detect insulin level and lipid profile, and then allocated into two groups according to metabolic syndrome existence. After the recommended surgery, and the routine histopathological diagnosis followed by histopathological chemilumeniscence technique to detect staining intensity, percentage of estrogen receptors ER, and score out of 8 according to Allred score.Results: Endometrial cancer EC patients with metabolic syndrome had a significantly higher age, higher FIGO stages, and higher grade compared to EC without metabolic syndrome (p˂0.05). There was no statically significant difference between both groups in estrogen receptors scoring. HDL was an important factor affecting grade of EC patients, as when HDL decreased by one mg/dl, the grade increased by 0.033% (P=0.030, OR=0.899, OR adjusted=0.826), Insulin level was found to be an important factor affecting stage as when insulin level increased by one Uiu/ml, the stage increased by1.091% (p=<0.001, OR=1.064, OR adjusted=1.091).Conclusions: Hyperinsulinemia was the most important factor affecting aggressiveness of the tumor as regards stage and risk group classification. Metformin failed to show a protective effect against endometrial cancer progression

Effects of quantum gravity on the inflationary parameters and thermodynamics of the early universe

The effects of generalized uncertainty principle (GUP) on the inflationary dynamics and the thermodynamics of the early universe are studied. Using the GUP approach, the tensorial and scalar density fluctuations in the inflation era are evaluated and compared with the standard case. We find a good agreement with the Wilkinson Microwave Anisotropy Probe data. Assuming that a quantum gas of scalar particles is confined within a thin layer near the apparent horizon of the Friedmann-Lemaitre-Robertson-Walker universe which satisfies the boundary condition, the number and entropy densities and the free energy arising form the quantum states are calculated using the GUP approach. A qualitative estimation for effects of the quantum gravity on all these thermodynamic quantities is introduced.Comment: 15 graghes, 7 figures with 17 eps graph

First-principles investigation of quantum emission from hBN defects

© 2017 The Royal Society of Chemistry. Hexagonal boron nitride (hBN) has recently emerged as a fascinating platform for room-temperature quantum photonics due to the discovery of robust visible light single-photon emitters. In order to utilize these emitters, it is necessary to have a clear understanding of their atomic structure and the associated excitation processes that give rise to this single photon emission. Here, we performed density-functional theory (DFT) and constrained DFT calculations for a range of hBN point defects in order to identify potential emission candidates. By applying a number of criteria on the electronic structure of the ground state and the atomic structure of the excited states of the considered defects, and then calculating the Huang-Rhys (HR) factor, we found that the CBVN defect, in which a carbon atom substitutes a boron atom and the opposite nitrogen atom is removed, is a potential emission source with a HR factor of 1.66, in good agreement with the experimental HR factor. We calculated the photoluminescence (PL) line shape for this defect and found that it reproduces a number of key features in the experimental PL lineshape