Técnica, princípios e características de avaliação da eficiência econômica da construção e reconstrução de rodovias

Efficiency assessment technique of capital investments in construction and reconstruction of highways is described in this article. Despite the degree of readiness of the methodical device, specialized construction norms of VSN 21-83 focused on implementation of such assessment were not widely adopted in view of the difficulties arising in the course of collecting basic data, their reliability and quality. The present article contains the characteristics of the grouped components and evaluation criteria, in particular, the description of settlement indicators in a section of the intra-transport, extra-transport and social and economic effects resulting from capital investments in linear objects of road infrastructure. On a concrete example the assessment procedure and calculations of summary economic indicators for groups and for the project in general is shown. What shows is a possibility of application of rather difficult technique and its efficiency as scientific tool of complex assessment for the solution of applied tasks in road construction. And use of departmental construction norms in combination with the dynamic methods of assessment based on the analysis of cash flows can increase substantially scientific validity of administrative decisions and quality of investment projects in the field of development of road infrastructure.En este artículo se describe la técnica de evaluación de la eficiencia de las inversiones de capital en la construcción y reconstrucción de carreteras. A pesar del grado de preparación del dispositivo metódico, las normas de construcción especializadas de VSN 21-83 enfocadas en la implementación de dicha evaluación no se adoptaron ampliamente en vista de las dificultades que surgen en el curso de la recopilación de datos básicos, su confiabilidad y calidad. El presente artículo contiene las características de los componentes agrupados y los criterios de evaluación, en particular, la descripción de los indicadores de asentamiento en una sección del transporte interno, transporte extra y los efectos sociales y económicos resultantes de las inversiones de capital en objetos lineales de infraestructura vial. En un ejemplo concreto se muestra el procedimiento de evaluación y los cálculos de indicadores económicos resumidos para grupos y para el proyecto en general. Lo que muestra es una posibilidad de aplicación de una técnica bastante difícil y su eficiencia como herramienta científica de evaluación compleja para la solución de tareas aplicadas en la construcción de carreteras. Y el uso de normas de construcción departamentales en combinación con los métodos dinámicos de evaluación basados en el análisis de flujos de efectivo puede aumentar sustancialmente la validez científica de las decisiones administrativas y la calidad de los proyectos de inversión en el campo del desarrollo de infraestructura vial.A técnica de avaliação de eficiência de investimentos de capital em construção e reconstrução de rodovias é descrita neste artigo. Apesar do grau de prontidão do dispositivo metódico, normas de construção especializadas do VSN 21-83 voltadas para a implementação de tal avaliação não foram amplamente adotadas em vista das dificuldades surgidas no decorrer da coleta de dados básicos, sua confiabilidade e qualidade. O presente artigo contém as características dos componentes agrupados e critérios de avaliação, em particular, a descrição dos indicadores de liquidação em uma seção dos efeitos intra-transporte, extra-transporte e sociais e econômicos resultantes de investimentos de capital em objetos lineares de infraestrutura rodoviária. Em um exemplo concreto, o procedimento de avaliação e os cálculos de indicadores econômicos resumidos para grupos e para o projeto em geral são mostrados. O que mostra é uma possibilidade de aplicação de técnica bastante difícil e sua eficiência como ferramenta científica de avaliação complexa para a solução de tarefas aplicadas na construção de estradas. E o uso de normas de construção departamental em combinação com os métodos dinâmicos de avaliação com base na análise dos fluxos de caixa pode aumentar substancialmente a validade científica das decisões administrativas e da qualidade dos projetos de investimento no campo do desenvolvimento da infraestrutura rodoviária

Self-dual Yang-Mills fields in pseudoeuclidean spaces

The self-duality Yang-Mills equations in pseudoeuclidean spaces of dimensions $d\leq 8$ are investigated. New classes of solutions of the equations are found. Extended solutions to the D=10, N=1 supergravity and super Yang-Mills equations are constructed from these solutions.Comment: 9 pages, LaTeX, no figure

Thermal Timescale Mass Transfer and the Evolution of White Dwarf Binaries

The evolution of binaries consisting of evolved main sequence stars (1 < M_d/Msun < 3.5) with white dwarf companions (0.7 < M_wd/Msun < 1.2) is investigated through the thermal mass transfer phase. Taking into account the stabilizing effect of a strong, optically thick wind from the accreting white dwarf surface, we have explored the formation of several evolutionary groups of systems for progenitors with initial orbital periods of 1 and 2 days. The numerical results show that CO white dwarfs can accrete sufficient mass to evolve to a Type Ia supernova and ONeMg white dwarfs can be built up to undergo accretion induced collapse for donors more massive than about 2 Msun. For donors less massive than ~2 Msun the system can evolve to form a He and CO or ONeMg white dwarf pair. In addition, sufficient helium can be accumulated (~0.1 Msun) in systems characterized by 1.6 < M_d/Msun < 1.9 and 0.8 < M_wd/Msun < 1 such that sub Chandrasekhar mass models for Type Ia supernovae, involving off center helium ignition, are possible for progenitor systems evolving via the Case A mass transfer phase. For systems characterized by mass ratios > 3 the system likely merges as a result of the occurrence of a delayed dynamical mass transfer instability. A semi-analytical model is developed to delineate these phases which can be easily incorporated in population synthesis studies of these systems.Comment: 9 pages, 6 figures, Latex, emulateapj style, ApJ accepte

Supernova Ia: a Converging Delayed Detonation Wave

A model of a carbon-oxygen (C--O) presupernova core with an initial mass 1.33 M_\odot, an initial carbon mass fraction 0.27, and with an average mass growth-rate 5 x 10^{-7} M_\odot/yr due to accretion in a binary system was evolved from initial central density 10^9 g/cm^3, and temperature 2.05 x 10^8 K through convective core formation and its subsequent expansion to the carbon runaway at the center. The only thermonuclear reaction contained in the equations of evolution and runaway was the carbon burning reaction 12C + 12C with an energy release corresponding to the full transition of carbon and oxygen (with the same rate as carbon) into 56Ni. As a parameter we take \alpha_c - a ratio of a mixing length to the size of the convective zone. In spite of the crude assumptions, we obtained a pattern of the runaway acceptable for the supernova theory with the strong dependence of its duration on \alpha_c. In the variants with large enough values of \alpha_c=4.0 x 10^{-3} and 3.0 x 10^{-3} the fuel combustion occurred from the very beginning as a prompt detonation. In the range of 2.0 x 10^{-3} >= \alpha_c >= 3.0 x 10^{-4} the burning started as a deflagration with excitation of stellar pulsations with growing amplitude. Eventually, the detonation set in, which was activated near the surface layers of the presupernova (with m about 1.33 M_\odot) and penetrated into the star down to the deflagration front. Excitation of model pulsations and formation of a detonation front are described in detail for the variant with \alpha_c=1.0 x 10^{-3}.Comment: 13 pages, 11 figures, to appear in Astronomy Letter

Patterns of mercury accumulation in the organs of bank vole Myodes glareolus (Rodentia, Cricetidae)

Mercury (Hg) and its compounds are among the most hazardous environmental pollutants with a high cumulative potential and they can have toxic effects on human and animal health even in low concentrations. Due to the increasing rate of human economic activity and the increase in the amount of Hg in the total cycling of matter, the study of its distribution, transformation, redistribution and accumulation in the abiotic and biotic components of various ecosystems remains important up to the present time. We assessed the content of metal in organs and tissues of the bank vole Myodes (Clethrionomys) glareolus Schreber, 1780 (Rodentia, Cricetidae), a widespread small rodent, caught in different biotopes of forest-steppe and steppe zones of Voronezh region. Measurements of Hg in samples were carried out with a mercury analyzer RA-915+ with the accessory PYRO (Lumex) using the atomic absorption method of cold steam without preliminary sample preparation (the lower limit of mercury detection in samples was 0.001 mg/kg). The sample size was 344 specimens. Mean Hg concentrations ranged from values below the analytical determination threshold to 0.887 mg/kg dry weight in the kidneys, 0.411 in the liver, 0.031 in the muscle tissue, and 0.040 in the brain. A positive correlation was found between the metal content in all possible pairs of organs (except for the “muscle – brain” pair) and a weak negative correlation was found between the Hg level and the mass of the animals. Hg concentrations in the studied organs did not differ between males and females. The metal content in the liver and kidneys of voles from the forest-steppe zone was significantly higher than in those from the steppe zone. Among all studied biotopes (meadow, pine and mixed forest, shrub thickets), the lowest concentrations were observed in animals living in pine forests, while the highest one – in more humidified bush thickets. During the vegetation season, there was a decrease in the average values of animal body mass in the samples and an increase in the content of Hg in the liver and kidneys. The results of the study are relevant in the assessment of atmospheric mercury pollution of terrestrial ecosystems using small mammals, such as Myodes glareolus, as a model object

Non-Abelian Vortices, Super-Yang-Mills Theory and Spin(7)-Instantons

We consider a complex vector bundle E endowed with a connection A over the eight-dimensional manifold R^2 x G/H, where G/H = SU(3)/U(1)xU(1) is a homogeneous space provided with a never integrable almost complex structure and a family of SU(3)-structures. We establish an equivalence between G-invariant solutions A of the Spin(7)-instanton equations on R^2 x G/H and general solutions of non-Abelian coupled vortex equations on R^2. These vortices are BPS solitons in a d=4 gauge theory obtained from N=1 supersymmetric Yang-Mills theory in ten dimensions compactified on the coset space G/H with an SU(3)-structure. The novelty of the obtained vortex equations lies in the fact that Higgs fields, defining morphisms of vector bundles over R^2, are not holomorphic in the generic case. Finally, we introduce BPS vortex equations in N=4 super Yang-Mills theory and show that they have the same feature.Comment: 14 pages; v2: typos fixed, published versio