Compton effect on relativistic electrons in the atmosphere of the sun

Compton effect on relativistic electrons in solar atmospher

The moving boundary problem in the presence of a dipole magnetic field

An exact analytic solution is obtained for a uniformly expanding, neutral, infinitely conducting plasma sphere in an external dipole magnetic field. The electrodynamical aspects related to the radiation and transformation of energy were considered as well. The results obtained can be used in analyzing the recent experimental and simulation data.Comment: 17 pages, 1 figure, Submitted to J. Phys. A, Math. and Genera

The New White Flight

White charter school enclaves—defined as charter schools located in school districts that are thirty percent or less white, but that enroll a student body that is fifty percent or greater white— are emerging across the country. The emergence of white charter school enclaves is the result of a sobering and ugly truth: when given a choice, white parents as a collective tend to choose racially segregated, predominately white schools. Empirical research supports this claim. Empirical research also demonstrates that white parents as a collective will make that choice even when presented with the option of a more racially diverse school that is of good academic quality. Despite the connection between collective white parental choice and school segregation, greater choice continues to be injected into the school assignment process. School choice assignment policies, particularly charter schools, are proliferating at a substantial rate. As a result, parental choice rather than systemic design is creating new patterns of racial segregation and inequality in public schools. Yet the Supreme Court’s school desegregation jurisprudence insulates racial segregation in schools ostensibly caused by parental choice rather than systemic design from regulation. Consequently, the new patterns of racial segregation in public schools caused by collective white parental choice largely escapes regulation by courts. This article argues that the time has come to reconsider the legal and normative viability of regulating racial segregation in public schools caused by collective white parental choice. The article makes two important contributions to the legal literature on school desegregation. First, using white charter school enclaves as an example, it documents the ways in which school choice policies are being used to allow whites as a collective to satisfy their preference for segregated predominately white schools. Second, the article sets forth both constitutional and normative arguments for regulating the private choices that result in stark racial segregation patterns in public schools

Comparing conductance quantization in quantum wires and Quantum Hall systems

We propose a new calculation of the DC conductance of a 1-dimensional electron system described by the Luttinger model. Our approach is based on the ideas of Landauer and B\"{u}ttiker and on the methods of current algebra. We analyse in detail the way in which the system can be coupled to external reservoirs. This determines whether the conductance is renormalized or not. We show that although a quantum wire and a Fractional Quantum Hall system are described by the same effective theory, their coupling to external reservoirs is different. As a consequence, the conductance in the wire is quantized in integer units of $e^2/h$ per spin orientation whereas the Hall conductance allows for fractional quantization.Comment: 3 pages, LaTe

Molecular-genetic factors of genital endometriosis

Article concerns data of the comparative analysis of polymorphic options of genes at patients with genital endometriosis and women in control grou

Detection of a flow induced magnetic field eigenmode in the Riga dynamo facility

In an experiment at the Riga sodium dynamo facility, a slowly growing magnetic field eigenmode has been detected over a period of about 15 seconds. For a slightly decreased propeller rotation rate, additional measurements showed a slow decay of this mode. The measured results correspond satisfactory with numerical predictions for the growth rates and frequencies

A bioinformatic search for correspondence between differentially expressed genes of domestic versus wild animals and orthologous human genes altering reproductive potential

One of the greatest achievements of genetics in the 20th century is D.K. Belyaev’s discovery of destabilizing selection during the domestication of animals and that this selection affects only gene expression regulation (not gene structure) and influences systems of neuroendocrine control of ontogenesis in a stressful environment. Among the experimental data generalized by Belyaev’s discovery, there are also findings about accelerated extinction of testes’ hormonal function and disrupted seasonality of reproduction of domesticated foxes in comparison with their wild congeners. To date, Belyaev’s discovery has already been repeatedly confirmed, for example, by independent observations during deer domestication, during the use of rats as laboratory animals, after the reintroduction of endangered species such as Przewalski’s horse, and during the creation of a Siberian reserve population of the Siberian grouse when it had reached an endangered status in natural habitats. A genome-wide comparison among humans, several domestic animals, and some of their wild congeners has given rise to the concept of self-domestication syndrome, which includes autism spectrum disorders. In our previous study, we created a bioinformatic model of human self-domestication syndrome using differentially expressed genes (DEGs; of domestic animals versus their wild congeners) orthologous to the human genes (mainly, nervous-system genes) whose changes in expression affect reproductive potential, i.e., growth of the number of humans in the absence of restrictions caused by limiting factors. Here, we applied this model to 68 human genes whose changes in expression alter the reproductive health of women and men and to 3080 DEGs of domestic versus wild animals. As a result, in domestic animals, we identified 16 and 4 DEGs, the expression changes of which are codirected with changes in the expression of the human orthologous genes decreasing and increasing human reproductive potential, respectively. The wild animals had 9 and 11 such DEGs, respectively. This difference between domestic and wild animals was significant according to Pearson’s χ2 test (p < 0.05) and Fisher’s exact test (p < 0.05). We discuss the results from the standpoint of restoration of endangered animal species whose natural habitats are subject to an anthropogenic impact

Coulomb drag shot noise in coupled Luttinger liquids

Coulomb drag shot noise has been studied theoretically for 1D interacting electron systems, which are realized e.g. in single-wall nanotubes. We show that under adiabatic coupling to external leads, the Coulomb drag shot noise of two coupled or crossed nanotubes contains surprising effects, in particular a complete locking of the shot noise in the tubes. In contrast to Coulomb drag of the average current, the noise locking is based on a symmetry of the underlying Hamiltonian and is not limited to asymptotically small energy scales.Comment: 4 pages Revtex, accepted for publication in PR

Упрощенный метод механического расчета гибких проводников распределительных устройств без ограничений по числу отпаек

The purpose of the mechanical calculation of flexible conductors of switchgears and power lines is to determine the sag, tensions, and loads on support structures, minimum distances to adjacent live parts and some other parameters. Calculations should be made taking into account distributed and concentrated loads. Distributed loads directed vertically are determined by the weight of the wire, insulator strings, and possible ice deposits on them. Distributed loads in the horizontal plane should be calculated in climatic conditions with lateral wind pressure. Concentrated loads are created by such elements as taps to electrical devices, phase-to-phase insulating spacers, barrier balls, loops, etc. Concentrated loads mainly act in the vertical plane, and in the case of taps, they can have an almost arbitrary spatial direction. The most accurate methods of mechanical calculation of flexible conductors include methods based on the numerical solution of the equation of wires in the form of a flexible elastic thread. Such an algorithm is implemented in the author's computer program MR21. However, in many cases, simplified methods of mechanical calculation are preferable, as they are available to a wider range of users. The simplified method of mechanical calculation of flexible conductors proposed in the article is based on the equation of state of the wire and allows taking into account concentrated and distributed loads. Various climatic regimes and loads are taken into account using the horizontal and vertical load factors in the calculated and initial modes. Expressions are proposed for calculating the above coefficients for any number of taps in a span and with an accurate approach to taking into account their spatial arrangement. Formulas for calculating sag and horizontal deflections of conductors are given, too. The MR21 computer program, tested earlier, has been used in this work as a tool for checking the calculation results using the proposed simplified method. Целью механического расчета гибких проводников распределительных устройств и линий электропередачи является определение стрел провеса, тяжений, нагрузок на опорные конструкции, минимальных расстояний до соседних токоведущих частей и других параметров. Расчеты должны производиться с учетом распределенных и сосредоточенных нагрузок. Распределенные нагрузки, направленные вертикально, определяются весом провода, гирлянд изоляторов, возможных гололедных отложений на них. Распределенные нагрузки в горизонтальной плоскости должны рассчитываться в климатических режимах с боковым напором ветра. Сосредоточенные нагрузки создаются такими элементами, как отпайки к электрическим аппаратам, междуфазные изолирующие распорки, заградительные шары, шлейфы и т. п., и действуют преимущественно в вертикальной плоскости, а в случае отпаек могут иметь практически произвольное пространственное направление. К наиболее точным методам механического расчета гибких проводников относят методы, основанные на численном решении уравнения проводов в виде гибкой упругой нити. Такой алгоритм реализован в авторской компьютерной программе MR21. Однако во многих случаях предпочтительными оказываются упрощенные методики, доступные более широкому кругу пользователей. В статье представлена упрощенная методика механического расчета гибких проводников, базирующаяся на уравнении состояния провода, позволяющая учитывать сосредоточенные и распределенные нагрузки. Различные климатические режимы и нагрузки учитываются с помощью коэффициентов горизонтальной и вертикальной нагрузки в рассчитываемом и исходном режимах. Приведены выражения для расчета вышеуказанных коэффициентов для любого числа отпаек в пролете с точным определением их пространственного расположения, а также представлены формулы для расчета стрел провеса и горизонтальных отклонений проводников. Компьютерная программа MR21, апробированная ранее, в данной работе используется в качестве инструмента проверки результатов расчета по предлагаемой упрощенной методике