1,704 research outputs found

    The thermodynamic structure of Einstein tensor

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    We analyze the generic structure of Einstein tensor projected onto a 2-D spacelike surface S defined by unit timelike and spacelike vectors u_i and n_i respectively, which describe an accelerated observer (see text). Assuming that flow along u_i defines an approximate Killing vector X_i, we then show that near the corresponding Rindler horizon, the flux j_a=G_ab X^b along the ingoing null geodesics k_i normalised to have unit Killing energy, given by j . k, has a natural thermodynamic interpretation. Moreover, change in cross-sectional area of the k_i congruence yields the required change in area of S under virtual displacements \emph{normal} to it. The main aim of this note is to clearly demonstrate how, and why, the content of Einstein equations under such horizon deformations, originally pointed out by Padmanabhan, is essentially different from the result of Jacobson, who employed the so called Clausius relation in an attempt to derive Einstein equations from such a Clausius relation. More specifically, we show how a \emph{very specific geometric term} [reminiscent of Hawking's quasi-local expression for energy of spheres] corresponding to change in \emph{gravitational energy} arises inevitably in the first law: dE_G/d{\lambda} \alpha \int_{H} dA R_(2) (see text) -- the contribution of this purely geometric term would be missed in attempts to obtain area (and hence entropy) change by integrating the Raychaudhuri equation.Comment: added comments and references; matches final version accepted in Phys. Rev.

    An Analysis of Major Determinants of Poverty in Agriculture Sector in Pakistan

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    Replaced with revised version of paper 05/21/08.Food Security and Poverty,

    Racial and Ethnic Health Disparities in Incarcerated Populations

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    Alarming disparities in population health and wellness in the United States have led to multi-disciplinary research efforts to create health equity. Identifying disparities, elucidating the etiological bases of disparities, and implementing solutions to eliminate disparities are part of the U.S. national health agenda. Racial and ethnic disparities have been identified throughout the cancer control continuum, in cardiovascular disease, diabetes and a multitude of other conditions. The causes of disparities are complex, condition specific, and conjectured to result from combinations of biological and socio-behavioral factors. Racial and ethnic health disparities within the vast incarcerated communities have been excluded from most studies, yet are of significant ethical and fiscal concern to inmates, governing bodies, and non-incarcerated communities into which inmates return. Importantly, research on racial and ethnic disparities in this unique population may shed light on the relative etiologies of health disparities and solutions for creating health equity throughout the general population in the United States

    Assessment of Salivary and Serum Proteins in Patients with Oral Tumors

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    The qualified subjects for this study included 33 patients with benign and malignant oral tumors aged 15-75 years and 31 matched age and gender healthy subjects used as control. Proteins measurements included total protein, albumin, globulines in sera and saliva samples, and immunoglobulins (IgG, IgM, IgA) in sera samples of control and patients. Meanwhile, polyacrylamide gel electrophoresis (PAGE) was used to differentiate between protein patterns in both serum and saliva samples among the studied groups. The gel was also stained for glycoprotein to evaluate as well the changes in glycoprotein contents. For total protein, the results revealed a signifigant increase (P?0.01) in both samples (serum and saliva) of patient group. Albumin concentration shows presence of a high significant decrease (P=0.001) in sera samples but a significant increase (

    Holographic repulsion and confinement in gauge theory

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    We show that for asymptotically anti-deSitter backgrounds with negative energy, such as the AdS soliton and regulated negative mass AdS-Schwarzshild metrics, the Wilson loop expectation value in the AdS/CFT conjecture exhibits a Coulomb to confinement transition. We also show that the quark-antiquark (qqˉq \bar q) potential can be interpreted as affine time along null geodesics on the minimal string world sheet,and that its intrinsic curvature provides a signature of transition to confinement phase. The result demonstrates a UV/IR relation in that the boundary separation of the qqˉq \bar{q} pair exhibits an inverse relationship with the radial descent of the world sheet into the bulk. Our results suggest a generic (holographic) relationship between confinement in gauge theory and repulsive gravity, which in turn is connected with singularity avoidance in quantum gravity.Comment: 8 pages, 4 figure

    Landscape and culture : Jeddah's seafront design

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    Jeddah is the second largest city in Saudi Arabia. It is located at the eastern edge of the Red Sea. The city expanded to the north and the south during its "boom period" in 1970s, constrained in the east by the airport area, and in the west by the Red Sea. By the middle of 1970s, Jeddah's growth was mainly directed to the north because of the availability of large low-density residential land in the north. The new airport also stimulated its growth. At the same time, new residential subdivisions developed rapidly between the old city and the new airport along the main highway to the north and along the coast in the west. The growth towards the north continued into the 1980s and even extended beyond the new airport zone, as vacant land in the middle of the old city and the new airport had been filled. This rapid growth, in turn, required a rapid development in infrastructure, city services and recreation areas. The master plan of the city in 1973s took into consideration the coast line and the recreation areas of the city considering these areas from the point of view of land use, but without consideration of the country's culture. These recreation places -- and especially the seafront area - therefore lacked activities for some visitor groups, and the design in general ignored their needs, which required special attention and methods if they were to be met. This project intends to discover the methods and the techniques that can be used to guide the new development of the city's southern coast, and in particular, revitalizing the seaside with a view to implementing the city dwellers' desire for a seafront that respects their culture and needs. The goal of this project is to create a design that transforms the traditional thinking for open space design in Saudi Arabia taking into consideration the dwellers cultures and desires

    LOADING OF CLARITHROMYCIN AND PACLITAXEL ON SYNTHESIZED CdS/NiO NANOPARTICLES AS PROMISING NANOCARRIERS

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    Objective: In this study cadmium sulfide (CdS) and nickel oxide (NiO) nanoparticles were synthesized and applied as novel nanocarriers for antibacterial drug clarithromycin (CLA) and anticancer drug paclitaxel (PTX) to improve their physical properties and biological activities.Methods: Cadmium sulfide (CdS) and nickel oxide (NiO) nanoparticles were synthesized by chemical co-precipitation and thermochemical processing techniques respectively and loaded with clarithromycin (CLA) and paclitaxel (PTX) by simple new one-step reaction. Analytical measures including FTIR, PXRD, SEM, AFM, TGA, DSC and zeta potential where used for characterization. The in vitro release, antibacterial as well as anticancer activities were evaluated.Results: Analytical measures revealed that the loading involved physical complex formation rather than chemical modification with the high percent surface loading of the drugs on the nanoparticles. Solubility/dissolution study revealed higher significant* improvement in the solubility of CLA from NiO nanoparticles than that from CdS nanoparticles while the antibacterial activity of CLA was non-significantly improved. For PTX loaded on CdS and NiO nanoparticles showed non-significant change in its solubility, but remarkable significant* increase in its antitumor activity on MCF-7 cell line accompanied with significant* reduction in its cytotoxicity on normal mammary cell line (MCF-10A) indicating the selectivity and targeting of PTX-CdS/NiO nanocarriers with reduced side effects of the drug and the used metal nanocarriers.Conclusion: This work provided most selective and safe delivery system for PTX and best method for enhancement of CLA solubility.Keywords: Clarithromycin (CLA), Paclitaxel (PTX), Cadmium sulfide (CdS) nanoparticles, Nickel oxide (NiO) nanoparticlesÂ
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