Supernova explosions are described as very violent events which transfer a significant amount of energy to interstellar media and are responsible for a large variety of physical processes. This study does not discuss the actual explosion mechanisms but follows the behavior of the dynamical evolution of some selected type I and type II supernova remnant and particularly after a thousand years from their explosion and shows how the density of the medium affects the evolution and the lifetime of each remnant. By studying such behaviors, a simplified model has been proposed here for the velocity and radius of the remnant after thousand years of explosion that depends only on the density of the medium and age of the remnant. It has been found th

Abstract

The entities responsible for regulating the financial market are seeking to provide high quality accounting information, to provide appropriate protection to investors, and thus encourage them and attract them to increase their investments. the research reached several conclusion, the most prominent of which comes  :-

1-The production of high quality accounting information reduces investment costs and costs of processing accounting information.

2- The production of high quality accounting information helps investors identify the best investment opportunities.

3- The results of the statistical analysis showed that there is significant

  This research studies the effect of grain size for the final stage in sintering Al2O3 .The experimental results for α- Al2O3 powder are modeled using ( L2-Regression ) technique in  order to study the effect grain size distribution on densification rate using four kinds for the initial particle size which were ( 1.44 , 2.54 , 0.7-2.54 ,1.15-3.53 ) µm , and for sintering time  (0-241) min. The mathematical simulation for grain size changing shows that the densification rates boots up as the grain size goes lower, this was due to the increase of contact area between the grains.

The research problem is dedicated to investigate reservoirs irrational economic behavior adopted by the ruling elites in developing countries about the investment methodology of human capital and operating policies is based on the terms of reference of economic theory and standards governing the market, which led to a chronic structural imbalance in the workforce structure and lack of consistency with different production structure, in turn, which had a reported effects in the emergence of the phenomenon of unemployment and that they involved a certain privacy, as has become the issues of unemployment and employment in the various countries of the world are issues more important due to the presence of large numbers of the workforce in th

Background: Osteoarthritis (OA) currently seems
inevitable and unavoidable for a large swath of the
population .its etiology relates to a strong ,but
complex ,non mendelian genetic basis ,combined
with mechanical and metabolic factors that cause
molecular alterations the end results of which
affect the whole joint .Glucosamine and
chondrotin sulfate alone or in combination may be
of benefit to a subgroup of individuals who have
knee pain due to OA.
Glucosamine has been shown to alter cartiage turn
over in patients with OA undergoing physical
training
Aim of the study: To find the validity of
glucosamine chondrotin sulfate in treatment of
grade 1 and 2 OA.
Methods: the sample of 280 patients

               This paper studies the effect of the solar indices (total sunspot no., solar wind density and coronal mass ejection linear speed) on F₂- layer electron density, as well as, the comparison of seasonal variations of electron density of F₂- layer, N_mF₂, for Mars at local noontime and for maximum and minimum solar cycles.                  

 Results show that there is an inverse correlation between sunspot number, solar wind density, CME linear speed and ionosphere electron density for Mars, at maximum and minimum solar cycles. This correlation is clear when electron density is at minimum value.                          

The current research aims to provide a philosophical and knowledge framework  to explain the issue of organizations dealing with Paradox phenomena by focusing on five main aspects. The first deals with the concept of paradox, and the second aspect deals with the types of forces paradox. While the third aspect regards subject of the philosophy of paradox in organization theory and the fourth side deals with methods of   solving the paradox. Finally, the last side is exposed to the subject of the paradoxes of the three provided by the study (L