Factors affecting the rotation rate of planets perycenter

Беручи до уваги відмінності релятивістського формулювання закону тяжіння від класичного в роботі показано, що швидкість повертання перигелію планет можна з достатньою точністю моделювати і в рамках релятивістської механіки.. One of the most precise tools for studying gravitational properties of matter is the effect of rotation of planets’ pericenter. Particularly, most of the spatial displacement of the perihelion of Mercury, which is caused by mutual influence of the planets, was calculated by Le Verrier based on the Newton’s law of inverse squares, and the discrepancy was later explained within the framework of general relativity. As a specific result is desirable to be obtained by the similar methods, there were attempts to apply the apparatus of relativistic mechanics for solving this problem; nevertheless, the calculated century bias of perihelion was three times less than observed one. However, in the relativistic problem of the bias rate of Mercury’s perihelion one should account for not only the equations of motion, but also other factors such as oblateness of the Sun, the orbital-rotational interaction of the planets, the redistribution of energy in the relativistic problem of two bodies, factors associated with modification of Newton’s law of gravity etc. On the other hand, there is increasing interest to the drawbacks of the general theory of relativity. Particularly, the latter cannot solve the problem of singularity with it internal contradictions with the field theory, the problem of torsion field is waiting for its solution. It is therefore important to consider some gravitational effects on related models, in particular within the framework of relativistic mechanics. This paper shows that additional contribution to Mercury’s perihelion bias rate is caused by three main factors: periodic relativistic change in mass of the planet, the difference between relativistic gravitational field and Newtonian one, and the relativistic moment of force. The last two factors in the literature have not yet been considered. The consequence of relativistic moment of force is to reverse the Lense–Thirring effect in special relativity, i.e. it leads to rotation of the Sun. This paper proves that within the framework of relativistic mechanics it is possible to calculate the rate of Mercury’s perihelion rotation with sufficient accuracy. The analysis held has shown that with the consistent observance of conservation laws there are no significant limitations in using the apparatus of relativistic mechanics for the analysis of planetary motion

The radiation balance of the earth-atmosphere system from Nimbus 3 radiation measurements

The radiation balance of the earth-atmosphere system and its components was computed from global measurements of radiation reflected and emitted from the earth to space. These measurements were made from the meteorological satellite Nimbus 3 during the periods from April 16 to August 15, 1969; October 3 to 17, 1969; and January 21 to February 3, 1970. Primarily the method of evaluation, its inherent assumptions, and possible error sources were discussed. Results are presented by various methods: (1) global, hemispherical, and zonal averages obtained from measurements in all semimonthly periods and (2) global maps of the absorbed solar radiation, the albedo, the outgoing longwave radiation, and the radiation balance obtained from measurements during semimonthly periods in each season (May 1 to 15, July 16 to 31, and October 3 to 17, 1969, and January 21 to February 3, 1970). Annual global averages of the albedo and of the outgoing longwave radiation were determined. These values balance to within 1 percent the annual global energy input by solar radiation that was computed for a solar constant

Conditions of brittle fracture initiation in solids containing thin elastic inclusions

Досліджено три основні механізми зародження руйнування в тілах із тонкими концентраторами напружень: безпосередньо в тілі, на межі поділу матеріалів та у самому включенні. При дослідженні руйнування тіла поблизу включення проаналізовано застосування критеріїв на основі силових функцій, J-інтеграла, густини енергії деформації. Також побудовано співвідношення, що оцінюють сумарну енергію деформації в зоні інтенсивності напружень поблизу вістря дефекту. При дослідженні руйнування межі включення–тіло побудовано залежності, що пов’язують узагальнені коефіцієнти інтенсивності напружень із максимальними значеннями контактних напружень у вершині заокругленого тонкого дефекту. Руйнування включення пов’язане із досягненням напруженнями чи деформаціями у ньому своїх критичних значень. Усі випадки проілюстровано числовими розрахунками конкретних прикладів.This paper studies three main fracture initiation mechanisms in solids with thin stress concentrators: directly in the solid; on the solid-inclusion interface and inside the inclusion. For studying of fracture of solid near inclusion it provides the analysis of fracture criterions based on the force functions, J-integral, strain energy density. Also the equation, which accounts the total strain energy in the stress intensity zone near the defect’s tip, is received. For studying of fracture of inclusion-matrix interface the relations of stress concentration and generalized stress intensity factors are obtained. Inclusion’s fracture is related with the critical values of its internal strain or stress. The numerical analysis of certain problems is provided

Integral equations of plane magnetoelectroelasticity for a half-space with cracks and thin inclusions

На основі формалізму Стро та методів теорії функції комплексної змінної побудовано інтегральні рівняння для магнітоелектропружного півпростору з отворами, тріщинами і тонкими включеннями. У цих рівняннях поряд з існуючими додатково враховано задане на межі півпростору навантаження. На основі отриманих інтегральних співвідношень побудовано схему методу граничних елементів для вивчення магнітоелектропружних півпросторів із тонкими неоднорідностями. Ефективність та достовірність числового алгоритму підтверджено зіставленням розв’язків конкретних задач із відомими в літературі. Отримано розв’язки нових задач для тріщин і тонких включень у магнітоелектропружному півпросторі.This paper presents a novel approach for obtaining the boundary integral equations of magnetoelectroelasticity for a half-space. This approach is based on the complex variable technique and the Stroh formalism. There are two fundamental relations used: the Cauchy integral formula and the Stroh orthogonality relations. The Cauchy integral formula is applied to the Stroh complex functions, which define the solution of 2D magnetoelectroelasticity. The boundary conditions at the boundary of the half-space are accounted for to obtain the integral formula for the Stroh complex functions inside the half-space. The Stroh orthogonality relations allow obtaining a useful identity, relating the vector of the Stroh complex functions with the displacement, electric and magnetic potentials and tractions, electric displacement and magnetic induction. This relation is applied to the integral formulae obtained and the Somigliana type identities are derived for a magnetoelectroelastic half-space. Using the Sokhotski–Plemelj formula the dual boundary integral equations are obtained. Derived boundary integral equations have several advantages in comparison with the existing ones: (1) these equations are obtained straightforward using a solid elegant complex variable approach; (2) the kernels are derived in transparent and easy way without any preliminary assumptions; (3) the integral formulae obtained account for the load set at the boundary of a half-space; (4) there are explicit closed-form expressions for all kernels of the dual boundary integral equations, which contain only the constants of the Stroh formalism. Obtained boundary integral equations along with the previously developed model of a thin magnetoelectroelastic inclusion are incorporated into the boundary element method. The approach is verified by comparison of the obtained results of particular problems with those referenced in literature. New results are presented for cracks and thin inclusions in the magnetoelectroelastic half-space. It is shown that even under the only mechanical load the significant intensity of electric and magnetic fields is present at the tips of inhomogeneity, which is close to the boundary of the half-space

On supersymmetry breaking vacua from D-branes at orientifold singularities

We present a large class of models of D-branes at (orientifold) Calabi-Yau sin- gularities which enjoy dynamical supersymmetry breaking at low energy, by means of either the SU(5) or 3\u20132 supersymmetry breaking models. Once embedded in a warped throat or, equivalently, in a large N theory, all models display an instability along a Coulomb branch direction towards supersymmetry preserving vacua. Interestingly, the nature of the run- away mechanism is model-independent and has a precise geometrical interpretation. This naturally suggests the properties a Calabi-Yau singularity should have in order for such instability not to occur

Assembly, trafficking and function of gamma-secretase

gamma-Secretase catalyzes the final cleavage of the beta-amyloid precursor protein to generate amyloid-beta peptide, the principal component of amyloid plaques in the brains of patients suffering from Alzheimer's disease. Here, we review the identification of gamma-secretase as a protease complex and its assembly and trafficking to its site(s) of cellular function. In reconstitution experiments, gamma-secretase was found to be composed of four integral membrane proteins, presenilin (PS), nicastrin (NCT), PEN-2 and APH-1 that are essential and sufficient for gamma-secretase activity. PS, which serves as a catalytic subunit of gamma-secretase, was identified as a prototypic member of novel aspartyl proteases of the GxGD type. In human cells, gamma-secretase could be further defined as a heterogeneous activity consisting of distinct complexes that are composed of PS1 or PS2 and APH-1a or APH-1b homologues together with NCT and PEN-2. Using green fluorescent protein as a reporter we localized PS and gamma-secretase activity at the plasma membrane and endosomes. Investigation of gamma-secretase complex assembly in knockdown and knockout cells of the individual subunits allowed us to develop a model of complex assembly in which NCT and APH-1 first stabilize PS before PEN-2 assembles as the last component. Furthermore, we could map domains in PS and PEN-2 that govern assembly and trafficking of the complex. Finally, Rer1 was identified as a PEN-2-binding protein that serves a role as an auxiliary factor for gamma-secretase complex assembly. Copyright (c) 2006 S. Karger AG, Basel

The Thebesian valve and its significance for electrophysiologists

Background: Invasive cardiac procedures, such as arrhythmia ablation, cardiac resynchronisation therapy, percutaneous mitral annuloplasty and retrograde cardioplegia delivery require cannulation of the coronary sinus (CS). Detailed knowledge of the CS ostium region, including recognition of the presence of the Thebesian valve which sometimes covers the sinus, is a key to successfully carryout such procedures.Materials and methods: In the present study, 160 autopsied human hearts from both sexes were examined for the presence of the Thebesian valve. If identified, the histological structure of the valve was studied.Results: Five types of the CS valve were distinguished; all of them presented with a typical histological structure with the exception of the cord-like type, in which cells were similar to those of the conduction system of the heart.Conclusions: Proper identification of the CS valve and analysis of its size and histological features could have important implications for electrophysiologists

Racetrack FFAG muon decay ring for nuSTORM with triplet focusing

The neutrino beam produced from muons decaying in a storage ring would be an ideal tool for precise neutrino cross section measurements and the search for sterile neutrinos due to its precisely known flavour content and spectrum. In the proposed nuSTORM facility, pions would be directly injected into a racetrack storage ring, where the circulating muon beam would be captured. In this paper we show that a muon decay ring based on a racetrack scaling FFAG (Fixed Field Alternating Gradient) with triplet focusing structures is a very promising option with potential advantages over the FODO based solution. We discuss the ring concept, machine parameters, linear optics design, beam dynamics and the injection system