Tag: Research

University

September 25, 2018 at 1:13 pmCategory:General

Over time, the star clusters sink toward the center of the galaxy, where the intermediate mass black holes merge, forming a supermassive black hole. For more specific information, check out Danny Meyer. In this process, clusters that do not have sufficient mass, or located close enough to the center of the galaxy to survive, carrying the black hole. Amazing restaurateur wanted to know more. "We can not say it? occurred in M82, but we know that there may be both of those options, "says Phil coaches the University of Iowa, one of the authors," In addition, the M82 is the nearest to us the place where the conditions similar to those that existed in the early universe, with more emerging stars. " The data for these holes, produced by the method of measurement and analysis of their X-ray brightness and the spectrum over time. These observatories Chandra and XMM-Newton, show that changes in the emission of one of these objects, like small black holes masses found in the Milky Way. Using this information and theoretical models, the team Calculate the mass of the object, it ranges from 12,000 to 43,000 solar masses.

This mass is sufficient for an abundant emission of X-rays by the powerful pull of gas directly from their environment. The black hole is approximately at a distance of 290 light years from the center of the galaxy M82. According to the authors the study, so close she can be located only at the time of birth, her weight was more than 30,000 solar, otherwise it would be pulled toward the center galaxy. That is, she simply joined with a supermassive black hole. The second object is located 600 light-years in the projection from the center of the galaxy M82.

Periodic and random bursts of X-rays are direct evidence that the disk surrounding the second object, there is hot gas, which is the source of radiation. Detailed X-ray data show that the gas disk extends all the way until a stable orbit around a black hole. This behavior exists in our galaxy, around the black hole whose mass is small, but it's probably the first candidate for the role of black hole intermediate-mass. Radius stable internal orbit, depends on the mass and angle of the black hole. The best model for the emission of X-rays, is a rapidly spinning black hole with a mass in the range of 200 to 800 solar masses. "Results obtained in these studies are among the strongest evidence for the existence of black holes with intermediate mass, as of today, "said Feng," The evidence, look as convincing as well studied examples of stellar mass black holes in our galaxy. " Based on materials from the site

Milk Products

May 23, 2014 at 12:48 pmCategory:General

In September 2008, the international media has leaked information about "different kinds of melamine contamination of food products (milk, infant formula, yogurt, candy, chocolate, tea beverages) in China, Singapore, New Zealand, Hong Kong, the Republic of Korea at concentrations up to 2560 mg / kg "(according to the of Food Safety Authorities (INFOSAN) WHO / FAO). It was noted that melamine was added to the food and animal feed in order to simulate a high protein content – one of the most important indicators of quality, which determine its nutritional value. The classic and still the only universally accepted method for determining protein Arbitration is the method of Kjeldahl (also known as a method for determining total nitrogen by Kjeldahl). Small molecule contains melamine in its structure, six nitrogen atoms, so even a small admixture of a chemical compound capable of create the illusion of a high nutritional value or foods. Thus, an analysis by the Kjeldahl method is nonselective to the nature of the nitrogen atoms, ie Not "see" the difference between the nitrogen of the protein or other origin. In the current situation – falsification of milk and dairy products with melamine – it was necessary to offer a highly selective, sensitive and accurate method for the analysis of melamine.

These methods, in particular, combined separation methods of analysis, including chromatography. On October 1, 2008 in the Russian Federation and approved November 1, 2008 will come into force "Supplement number 11 to SanPiN 2.3.2.1078-01" according to which no allowed the presence of melamine in food (permissible level – less than 1 mg / kg). To determine the melamine in milk and milk products, the Federal Service for Supervision of Consumer Rights Protection and Human Welfare approved guidelines Municipal 4.1.2420-08 that establish HPLC method. Russian manufacturers of analytical instruments for the implementation of KMC 4.1.2420-08 offer to use their own production equipment, which allows solve the problem effectively, efficiently and economically. For the analysis of melamine is not only used HPLC method, but the method of capillary electrophoresis, which compared to the chromatographic separation is characterized by much higher resolution of the peaks, significantly lower cost than one definition, the absence of speakers, and problems with its replacement, in general, more simple practice of using the equipment while maintaining the same metrological parameters.