Brane Cosmology With Generalized Chaplygin Gas in The Bulk

We find exact solution of the Einstein equations in the context of the brane world scenario. We have supposed a {generalized chaplygin gas} equation of state for bulk. This study display a constant energy density and pressure for bulk in late time. It is shown that our assumptions impose a specific equation of state on brane. {In this work, we have obtained a decelerate universe in early time and late time.} In the end, it is shown that under some assumption we have equation of state of cosmological constant for bulk.Comment: 11 page

Isolation of keratinophilic fungi and aerobic actinomycetes from park soils in Gorgan, North of Iran

Background: Keratinophilic fungi are a group of fungi that colonize in various keratinous substrates and degrade them to the components with low molecular weight. This study was conducted to determine the prevalence of keratinophilic fungi and aerobic Actinomycetes in soil of city parks in Gorgan. Objectives: In this study, we surveyed the city park soils of Gorgan (a northern province of Iran) to determine the identities and diversity of soil aerobic Actinomycetes, keratinophilic and non-keratinophilic fungi. Materials and Methods: A total of 244 soil samples were collected from 22 diferent parks of Gorgan, North of Iran. The samples were collected from the superfcial layer with depth not exceeding than 0-10 cm in sterile polyethylene bags. We used hair bait technique for isolation keratinophilic fungi. The colonies identifed by macroscopic and microscopic characterization after slide culturing. Actinomycetes were isolated by antibiotic dilution methods and detected by using physiological tests such as Lysozyme, Casein, Xanthine, Hypoxanthine, Gelatin, Urea Broth, and modifed acid-fast stain. Results: Totally, 75 isolates of aerobic Actinomycetes were detected that Actinomadura madurae and Nocardia asteroides were the most prevalent strains, with 14.66 and 28% prevalence respectively. Microsporum gypseum was more frequent than other keratinophilic fungi (22.96%) and Aspergillus spp. was the most species of saprophyte fungi (15.92%). Conclusions: This study showed that the collected soil from studied areas was rich of keratinophilic fungi and Actinomycetes, therefore hygiene protocol should be taken to prevent the spread of pathogenic and saprophytes fungi in the environment of susceptible person. © 2013, Ahvaz Jundishapur University of Medical Sciences

Agegraphic Dark Energy Model in Non-Flat Universe: Statefinder Diagnostic and w−w′w-w^{\prime} Analysis

We study the interacting agegraphic dark energy (ADE) model in non-flat universe by means of statefinder diagnostic and $w-w^{\prime}$ analysis. First, the evolution of EoS parameter ($w_d$) and deceleration parameter ($q$) in terms of scale factor for interacting ADE model in non-flat universe are calculated. Dependence of $w_d$ on the ADE model parameters $n$ and $\alpha$ in different spatial curvatures is investigated. We show that the evolution of $q$ is dependent on the type of spatial curvature, beside of dependence on parameters $n$ and $\alpha$. The accelerated expansion takes place sooner in open universe and later in closed universe compare with flat universe. Then, we plot the evolutionary trajectories of the interacting ADE model for different values of the parameters $n$ and $\alpha$ as well as for different contributions of spatial curvature, in the statefinder parameters plane. In addition to statefinder, we also investigate the ADE model in non-flat universe with $w-w^{\prime}$ analysis.Comment: 20 pages, 4 figures, 2 tables, International Journal of Modern Physics D accepte

Emulating computer models with step-discontinuous outputs using Gaussian processes

In many real-world applications, we are interested in approximating functions that are analytically unknown. An emulator provides a "fast" approximation of such functions relying on a limited number of evaluations. Gaussian processes (GPs) are commonplace emulators due to their properties such as the ability to quantify uncertainty. GPs are essentially developed to emulate smooth, continuous functions. However, the assumptions of continuity and smoothness is unwarranted in many situations. For example, in computer models where bifurcation, tipping points occur in their systems of equations, the outputs can be discontinuous. This paper examines the capacity of GPs for emulating step-discontinuous functions using two approaches. The first approach is based on choosing covariance functions/kernels, namely neural network and Gibbs, that are most appropriate for modelling discontinuities. The predictive performance of these two kernels is illustrated using several examples. The results show that they have superior performance to standard covariance functions, such as the Mat\'ern family, in capturing sharp jumps. The second approach is to transform the input space such that in the new space a GP with a standard kernel is able to predict the function well. A parametric transformation function is used whose parameters are estimated by maximum likelihood.Engineering and Physical Sciences Research Council (EPSRC

Synthesis of mg/al layered double hydroxide (LDH) nanoplates for efficient removal of nitarate from aqueous solutions

Leaching of nitrate is an important issue on the losses of nitrate from agriculture soils in temperate zone. Decomposition of plants and other organic residues in the soil and improper discharge of sewage lead to the presence of nitrates in the sources of surface and groundwater and flowing water drainage in agricultural drainage networks and their pollution. This study aimed to study the potential use of chloride layered double hydroxide (LDH) nanoplates to remove nitrate from aqueous solutions. The nano-material of chloride-LDH was made by hydrothermal technique and then, its characteristics were specified through scanning electron micrograph and removal of nitrate from aqueous solution by the minerals was investigated in terms of pH, time, speed of shaker, different concentrations of adsorbent and surface adsorption isotherm. Microscopic images of built nanoplates were examined using FESEM and SEM electron microscope with two magnifications. The thickness of nanoplates was about 20nm and their diameter was about 250 nm. Magnified image of the synthesized nanostructures shows squamous-shape. Surface adsorption isotherm of nitrate by chloride- LDH nanoplate was explained with Langmuir model shown with the values greater than 2R. In surface adsorption of nitrate, the optimal values were measured as following: pH = 7, speed = 250 rpm, time = 45 min, concentration of adsorbent = 0.1gr.  This material could adsorb nitrates from aqueous solutions efficiently and effectively.Keywords: pollution, nitrate, layered double hydroxide, hydrothermal, surface adsorptio