Effects of three different doses of endosulfan respectively designated as low, medium and high on cytochrome P450(Cyt.P450), glutathione S-transferase(GST) activity and glutathione content (GSH) of ...hepatic and extra hepatic tissues of rat were determined after 24 hours of treatment. Endosulfan caused induction of cyt. P450 in liver, lung and brain at all the three doses tested while in kidney, spleen and heart either induction or reduction took place and was unrelated with dosages of endosulfan. Similarly, GST activity significantly changed in extra hepatic tissues while liver GST activity did not record any significant alteration under the experimental conditions. The GSH content also showed changes (increase/decrease) unrelated to endosulfan dosages in different organs. Thus, the effects varied with organ and dosages. As these metabolic parameters are involved in biotransformation of many endogenous molecules as well, the study may throw some light on physiological disturbances due to changes in metabolizing system on one side and organ specificity in toxic action of endosulfan on the other.
The next decade of survey astronomy has the potential to transform our knowledge of variable stars. Stellar variability underpins our knowledge of the cosmological distance ladder, and provides ...direct tests of stellar formation and evolution theory. Variable stars can also be used to probe the fundamental physics of gravity and degenerate material in ways that are otherwise impossible in the laboratory. The computational and engineering advances of the past decade have made large-scale, time-domain surveys an immediate reality. Some surveys proposed for the next decade promise to gather more data than in the prior cumulative history of astronomy. The actual implementation of these surveys will have broad implications for the types of science that will be enabled. We examine the design considerations for an optimal time-domain photometric survey dedicated to variable star science, including: observing cadence, wavelength coverage, photometric and astrometric accuracy, single-epoch and cumulative depth, overall sky coverage, and data access by the broader astronomical community. The best surveys must combine aspects from each of these considerations to fully realize the potential for the next decade of time-domain science.
LSST Science Book, Version 2.0 Abell, Paul A; Andrew, John R; Angel, J Roger P ...
arXiv (Cornell University),
12/2009
Paper, Journal Article
Odprti dostop
A survey that can cover the sky in optical bands over wide fields to faint magnitudes with a fast cadence will enable many of the exciting science opportunities of the next decade. The Large Synoptic ...Survey Telescope (LSST) will have an effective aperture of 6.7 meters and an imaging camera with field of view of 9.6 deg^2, and will be devoted to a ten-year imaging survey over 20,000 deg^2 south of +15 deg. Each pointing will be imaged 2000 times with fifteen second exposures in six broad bands from 0.35 to 1.1 microns, to a total point-source depth of r~27.5. The LSST Science Book describes the basic parameters of the LSST hardware, software, and observing plans. The book discusses educational and outreach opportunities, then goes on to describe a broad range of science that LSST will revolutionize: mapping the inner and outer Solar System, stellar populations in the Milky Way and nearby galaxies, the structure of the Milky Way disk and halo and other objects in the Local Volume, transient and variable objects both at low and high redshift, and the properties of normal and active galaxies at low and high redshift. It then turns to far-field cosmological topics, exploring properties of supernovae to z~1, strong and weak lensing, the large-scale distribution of galaxies and baryon oscillations, and how these different probes may be combined to constrain cosmological models and the physics of dark energy.
Effect of acute doses of technical grade of dichloro diphenyl trichloro ethane (DDT) and piperonyl butoxide (PB) on hepatic microsomal cytochrome P450 (Cyt. P450) and cytosolic ...glutathione-S-transferase (GST) activity in pigeon were studied after 24 hours of treatment. A completely reverse trend of changes in Cyt. P450 and GST activity were found as increase in Cyt. P450 paralleled with decrease in GST activity following exposure to DDT. However, intensity of changes in Cyt. P450 was greater than that of GST. A dose dependent decrease in Cyt. P450 and GST activity was observed after PB treatment. The study may, therefore, throw some light on metabolic alterations in wild birds resulting from environmental pollution by DDT and allied chemicals.
