Note on flat foliations of spherically symmetric spacetimes

It is known that spherically symmetric spacetimes admit flat spacelike foliations. We point out a simple method of seeing this result via the Hamiltonian constraints of general relativity. The method yields explicit formulas for the extrinsic curvatures of the slicings.Comment: 4 pages, to appear in PRD, reference added, typos correcte

High- and low energy nonthermal X-ray emission from the cluster of galaxies A 2199

We report the detection of both soft and hard excess X-ray emission in the cluster of galaxies A 2199, based upon spatially resolved spectroscopy with data from the BeppoSAX, EUVE and ROSAT missions. The excess emission is visible at radii larger than 300 kpc and increases in strength relative to the isothermal component. The total 0.1-100 keV luminosity of this component is 15 % of the cluster luminosity, but it dominates the cluster luminosity at high and low energies. We argue that the most plausible interpretation of the excess emission is an inverse Compton interaction between the cosmic microwave background and relativistic electrons in the cluster. The observed spatial distribution of the non-thermal component implies that there is a large halo of cosmic ray electrons between 0.5-1.5 Mpc surrounding the cluster core. The prominent existence of this component has cosmological implications, as it is significantly changing our picture of a clusters's particle acceleration history, dynamics between the thermal and relativistic media, and total mass budgets.Comment: Accepted for publication in Astrophysical Journal, Letter

Mass Profiles of the Typical Relaxed Galaxy Clusters A2199 and A496

We present maps and radial profiles of the gas temperature in the nearby galaxy clusters A2199 and A496, which have the most accurate ASCA spectral data for all hot clusters. These clusters are relaxed and can provide reliable X-ray mass measurements under the assumption of hydrostatic equilibrium. The cluster average temperatures corrected for the presence of cooling flows are 4.8+-0.2 keV and 4.7+-0.2 keV (90% errors), respectively. Outside the central cooling flow regions, the radial temperature profiles are similar to those of the majority of nearby relaxed clusters. They are accurately described by polytropic models with gamma=1.17+-0.07 for A2199 and gamma=1.24+-0.09 for A496. We use these polytropic models to derive accurate total mass profiles. Within r=0.5/h Mpc, which corresponds to a radius of overdensity 1000, the total mass values are 1.45+-0.15 10^14 /h Msun and 1.55+-0.15 10^14 /h Msun. These values are 10% lower than those obtained assuming constant temperature. The values inside a gas core radius (0.07-0.13/h Mpc) are a factor of >1.5 higher than the isothermal values. The gas mass fraction increases with radius (by a factor of 3 between the X-ray core radius and r_1000) and at r_1000 reaches values of 0.057+-0.005 and 0.056+-0.006 h^-3/2 for the two clusters, respectively. Our mass profiles within r_1000 are remarkably well approximated by the NFW "universal" profile. Since A2199 and A496 are typical relaxed clusters, the above findings should be relevant for most such systems. In particular, the similarity of the temperature profiles in nearby clusters appears to reflect the underlying "universal" dark matter profile. The upward revision of mass at small radii will resolve most of the discrepancy between the X-ray and strong lensing mass estimates. (Abridged)Comment: Latex, 9 pages, 6 figures, uses emulateapj.sty. Submitted to Ap

Cost variation analysis of antipsychotic drugs available in Indian market: an economic perspective

Background: Pricing of drugs plays a very important role in a developing country like India especially in the management of chronic conditions. There exists a huge price variation among the different brands of the same drug. Hence this study was planned to find out variation in prices of antipsychotic drugs marketed in India. The objective was to compare the percentage price variation and cost ratio of various formulations of oral and parenteral antipsychotic drugs available in the Indian market.Methods: Cost of oral and parenteral antipsychotic drugs available in the Indian market manufactured by different companies, in the same strength, number and dosage form was obtained from http://www.medguideindia.com. The percentage price variation and cost ratio of each formulation was calculated.Results: Among the typical group of antipsychotic drugs, Tab Haloperidol 0.25mg shows maximum price variation of 650% and a cost ratio of 7.5 followed by Tab Trifluoperazine 1mg having a price variation of 555.5% and a cost ratio of 6.55. Among the atypical group of drugs, tab Risperidone 3mg shows a price variation of 2282.35% with a cost ratio of 23.82 followed by Tab Risperidone 4mg with a price variation of 1976.92 % and a cost ratio of 20.76.Conclusions: There is a wide variation between the minimum and maximum cost among the different brands of the same drug in the same formulations. Combined efforts are needed from the regulatory authorities, pharmaceutical companies, physicians and pharmacist towards controlling the prices and attaining maximum economic benefits for the patient

Effects of Variation of Quantum Well Numbers on Gain Characteristics of Type-I InGaAsP/InP Nano-heterostructure

This paper reports the effects of variation of number of quantum wells in material gain characteristics and lasing wavelength of step index separately confined type-I InGaAsP/InP lasing nano-heterostructure for different carrier concentrations at room temperature in TE (Transverse Electric) mode of polarization. Peak material gain is found to be highest when the number of quantum well is one in the structure. However, for the case of 3QWs, 5QWs and 7QWs, it is almost same at a particular carrier density. Lasing wavelength at peak material gain considerably increases as the number of quantum well layers vary from single quantum well layer to three quantum well layers in the active region and after that it will remain almost same by any further increase in number of quantum wells for a particular carrier density. Furthermore, negative gain condition in the material gain spectra exists in the case of multiple quantum wells only at carrier concentration of 2×1018/cm3. The results suggest that the proposed nano-heterostructure is highly suitable as a light source in fiber optic links for long distance communication

Foliation of the Kottler-Schwarzschild-De Sitter Spacetime by Flat Spacelike Hypersurfaces

There exist Kruskal like coordinates for the Reissner-Nordstrom (RN) black hole spacetime which are regular at coordinate singularities. Non existence of such coordinates for the extreme RN black hole spacetime has already been shown. Also the Carter coordinates available for the extreme case are not manifestly regular at the coordinate singularity, therefore, a numerical procedure was developed to obtain free fall geodesics and flat foliation for the extreme RN black hole spacetime. The Kottler-Schwarzschild-de Sitter (KSSdS) spacetime geometry is similar to the RN geometry in the sense that, like the RN case, there exist non-singular coordinates when there are two distinct coordinate singularities. There are no manifestly regular coordinates for the extreme KSSdS case. In this paper foliation of all the cases of the KSSdS spacetime by flat spacelike hypersurfaces is obtained by introducing a non-singular time coordinate.Comment: 12 pages, 4 figure

Comparative study of the modulation of fructose/sucrose-induced hepatic steatosis by mixed lipid formulations varying in unsaturated fatty acid content

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in developed countries. NAFLD encompasses a spectrum of diseases, ranging from hepatic steatosis to non-alcoholic steatohepatitis (NASH), cirrhosis, and liver failure. The etiology of NAFLD remains unclear but is thought to relate to increased fatty acid flux within the liver that results in toxic fatty acid metabolite production. One source of increased fatty acid flux is fructose/sucrose-induced hepatic lipogenesis. Current treatment for NAFLD encompasses dietary modifications. However, little scientific evidence exists on which to base many dietary recommendations, especially the intake of different types of carbohydrates and fats. We hypothesized that lipid mixtures of unsaturated fatty acids would inhibit lipogenesis and subsequent hepatic steatosis induced by high carbohydrate diets. The aim of this study was to examine the effects of different complex mixtures of fatty acids upon the development of fructose/sucrose-induced hepatic steatosis. METHODS: C57BL/6 mice were randomized to normocaloric chow-based diets that varied in the type of carbohydrate (starch, sucrose, fructose). Animals in each carbohydrate group were further randomized to diets that varied in lipid type (no additional lipid, soybean oil, fish oil, olive/soybean oil, macadamia nut oil). These oils were chosen based upon their content of omega-6 polyunsaturated fatty acids, omega-3 polyunsaturated fatty acids, omega-9 monounsaturated fatty acids, or omega-7 monounsaturated fatty acids. Fatty acid flux in the liver was determine by assessing hepatic lipid content (steatosis). We also assessed fatty acid levels in the plasma and liver of the animals, hepatic lipogenesis activity, hepatic stearoyl-CoA-1 desaturase activity, and hepatic elongase activity. RESULTS: Animals consumed similar amounts of the diets and maintained normal body weights throughout the study. Both sucrose and fructose induced hepatic lipogenesis and steatosis, with fructose being more potent. All mixed lipids similarly inhibited steatosis, limiting lipid content to levels found in the control (starch) animals. Lipogenesis and stearoyl-CoA-1 desaturase activity were increased in the sucrose and fructose groups. Levels of these enzymatic processes remained at baseline in all of the lipid groups. CONCLUSION: This is the first study to compare various complex lipid mixtures, based upon dietary oils with different types of long-chain fatty acids, upon development of sucrose/fructose-induced steatosis. Both carbohydrate source and lipid content appear important for the modulation of steatosis. Moderate intake of complex lipids with high unsaturated to saturated fatty acid ratios inhibited both lipogenesis and steatosis

Constraints on Type Ia Supernova Models from X-ray Spectra of Galaxy Clusters

We present constraints on theoretical models of Type Ia supernovae using spatially resolved ASCA X-ray spectroscopy of three galaxy clusters: Abell 496, Abell 2199 and Abell 3571. All three clusters have central iron abundance enhancements; an ensemble of abundance ratios are used to show that most of the iron in the central regions of the clusters comes from SN Ia. These observations are consistent with the suppressed galactic wind scenario proposed by Dupke and White (1999). At the center of each cluster, simultaneous analysis of spectra from all ASCA instruments shows that the nickel to iron abundance ratio (normalized by the solar ratio) is Ni/Fe ~ 4. We use the nickel to iron ratio as a discriminator between SN Ia explosion models: the Ni/Fe ratio of ejecta from the "Convective Deflagration" model W7 is consistent with the observations, while those of "delayed detonation" models are not consistent at the 90% confidence level.Comment: 20 pages, 2 figures, accepted by The Astrophysical Journa