Energy Release on the Surface of a Rapidly Rotating Neutron Star during Disk Accretion: A Thermodynamic Approach

The total energy E of a star as a function of its angular momentum J and mass M in the Newtonian theory: E = E(J, M) [in general relativity, the gravitational mass M of a star as a function of its angular momentum J and rest mass m, M = M(J, m)], is used to determine the remaining parameters (angular velocity, equatorial radius, chemical potential, etc.) in the case of rigid rotation. Expressions are derived for the energy release during accretion onto a cool (with constant entropy), rapidly rotating neutron star (NS) in the Newtonian theory and in general relativity. A separate analysis is performed for the cases where the NS equatorial radius is larger and smaller than the radius of the marginally stable orbit in the disk plane. An approximate formula is proposed for the NS equatorial radius for an arbitrary equation of state, which matches the exact one at J = 0.Comment: 12 pages, 0 figures (Astronomy Letters in press

Recovery of potential using module values of its gradient. 2

The method of the recovery of the potential on the module of its gradient under conditionof the similarity of the potential to that given as the limit of the succession of the solations of the boundary problems of Neumann for the Laplace equation that define the disturbing potential proposed in the first part is substantiated. The succession of the disturbing potential is generated by the succession of the solutions of linear integral equations of the second kind with compact operators having large cores. A correct solubility of the given kind of equations is established and the convergence of the succession of the solution of the Neumann's problems to the function unambiguously generating the desired potential is proven

Recovery of potential using module values of its gradient. 1

The history of the problem investigation is briefly described. Gravity is characterized. It is proven that no accurate boundary conditions can be deduced for any linear classical problem of the potential theory (including the problem of Stox – Molodensky for the Laplace equation) from the potential gradient module values. It is shown that the error of the transformations of the potential gradient module anomalies as harmonic functions depends on the carvature of the equipotential surfaces of the field, the amplitude of the anomalies and the measure of the domain in which the transformation is made. It is stated that the methods of processing and interpreting gravity and aeromagnetic anomalies developed on the basis of the theory of harmonic functions and successfully used in exploration geophysics may appear to be ineffective in studying the deep regional structure of the Earth. To pass through the crisis we propose a new definition of a non-linear boundary problem of recovering the attraction (or magnetic) potential in an unbounded closed domain from the values of the module of its gradient at the boundary of the domain provided the potential is similar to the given one. A method is proposed to solve the problem in a succession of the solutions of the Neumann's problems for the Laplace equation which determines the disturbing potential

Could erectile dysfunction in type 2 diabetes change the presumption of normative total blood serumtes tos terone ?

© Group of authors, 2016. According to research data, the ED is detected in 50-75 % of men with T2DM. During the last decade, the problem of ED in the presence of late onset hypogonadism has been actively studied. There is convincing proof that total serum testosterone (T) deficit influences the development and severity of ED, including in T2DM. The principal aim of the current study was to evaluate ED in males with T2DM at low and middle- To-high normative levels of T. We have performed a prospective randomized simple comparative study of 86 male patients with T2DM and T level higher than 12.0 nmol/l. The patients were divided into two groups, with low normative level of T and with middle - To high normative T levels. Standard methods of objective evaluation did not permit discrimination in the T2DM compensation. At the same time the diseases based on vascular pathology, dyslipidemia and vascular endothelial dysfunctions were more frequently found in patients with middle- To-high normal T levels. In the two groups of patients the severity of androgen deficiency symptoms was found out to be unequal. The IIEF-5 questionnaire showed significant difference in frequency and severity of ED and significant relation to T levels. Males with T2DM and normotestosteronemia at 12-15 mmol/l are at higher risks of dyslipidemia, endothelium disorders and progress of T2DM as compared to males with blood T of\u3e15 mmol/l