TYC 1031 01262 1: The First Known Galactic Eclipsing Binary with a Type II Cepheid Component

We present the discovery and CCD observations of the first eclipsing binary with a Type II Cepheid component in our Galaxy. The pulsation and orbital periods are found to be 4.1523 and 51.38 days, respectively, i.e. this variable is a system with the shortest orbital period among known Cepheid binaries. Pulsations dominate the brightness variations. The eclipses are assumed to be partial. The EB-subtype eclipsing light curve permits to believe that the binary's components are non-spherical.Comment: 3 pages, 3 figures, accepted to MNRAS Letter

Information security for college students

The content of the article deals with the essence of the concepts of "security", "information security", "security threat", "economic security". The author analyzes in more detail the concept of "information security"В содержании статьи рассматривается сущность понятий «безопасность», «информационная безопасность», «угроза безопасности», «экономическая безопасность». Автор более подробно анализирует понятие «информационная безопасность

A tractable model for indices approximating the growth optimal portfolio

The growth optimal portfolio (GOP) plays an important role in finance, where it serves as the numéraire portfolio, with respect to which contingent claims can be priced under the real world probability measure. This paper models the GOP using a time dependent constant elasticity of variance (TCEV) model. The TCEV model has high tractability for a range of derivative prices and fits well the dynamics of a global diversified world equity index. This is confirmed when pricing and hedging various derivatives using this index

SFB 649 Discussion Paper 2006-075 Inhomogeneous Dependency Modelling with Time Varying

Measuring dependence in a multivariate time series is tantamount to modelling its dynamic structure in space and time. In the context of a multivariate normally distributed time series, the evolution of the covariance (or correlation) matrix over time describes this dynamic. A wide variety of applications, though, requires a modelling framework different from the multivariate normal. In risk management the non-normal behaviour of most financial time series calls for nonlinear (i.e. non-gaussian) dependency. The correct modelling of non-gaussian dependencies is therefore a key issue in the analysis of multivariate time series. In this paper we use copulae functions with adaptively estimated time varying parameters for modelling the distribution of returns, free from the usual normality assumptions. Further, we apply copulae to estimation of Value-at-Risk (VaR) of a portfolio and show its better performance over the RiskMetrics approach, a widely used methodology for VaR estimation. JEL classification: C 1

A Hybrid Model for Pricing and Hedging of Long-dated Bonds

© 2015 Taylor & Francis. Abstract: Long-dated fixed income securities play an important role in asset-liability management, in life insurance and in annuity businesses. This paper applies the benchmark approach, where the growth optimal portfolio (GOP) is employed as numéraire together with the real-world probability measure for pricing and hedging of long-dated bonds. It employs a time-dependent constant elasticity of variance model for the discounted GOP and takes stochastic interest rate risk into account. This results in a hybrid framework that models the stochastic dynamics of the GOP and the short rate simultaneously. We estimate and compare a variety of continuous-time models for short-term interest rates using non-parametric kernel-based estimation. The hybrid models remain highly tractable and fit reasonably well the observed dynamics of proxies of the GOP and interest rates. Our results involve closed-form expressions for bond prices and hedge ratios. Across all models under consideration we find that the hybrid model with the 3/2 dynamics for the interest rate provides the best fit to the data with respect to lowest prices and least expensive hedges

The architecture of business centers in major cities of independent Kazakhstan

Introduction: The study aims to determine the main trends in the formation of business centers in Kazakhstan’s two largest cities, Almaty and Nur-Sultan, and to develop the main city planning and architectural recommendations for improving the network of business centers and their maintenance. Materials and Methods: The study’s systemic and complex research methodology allows it to look at business center issues from a variety of perspectives, including economic, socio-political, legislative, urban planning, and innovation. This approach allowed the architecture of business centers to be highlighted as a dynamic, interrelated process that represents the state’s economic power and prestige. Results and Discussion: The identification of trends in the development of business centers as the main type of commercial real estate is intrinsically linked to their natural qualitative growth and structural metamorphoses, transforming future cities into business cities, business parks, business incubators, and eco-towns. Conclusions: The study revealed that a specific feature of the business center is the distinction in its space-planning structure of the recreational and communicative block of premises and rooms into a separate independent functional block, which, both locally and dispersed spatially, carries an ideological and logical practical load and is a functional space for a multi-purpose business building

Dependence Modelling in Insurance via Copulas with Skewed Generalised Hyperbolic Marginals

© 2019 Walter de Gruyter GmbH, Berlin/Boston. This paper investigates dependence among insurance claims arising from different lines of business (LoBs). Using bivariate and multivariate portfolios of losses from different LoBs, we analyse the ability of various copulas in conjunction with skewed generalised hyperbolic (GH) marginals to capture the dependence structure between individual insurance risks forming an aggregate risk of the loss portfolio. The general form skewed GH distribution is shown to provide the best fit to univariate loss data. When modelling dependency between LoBs using one-parameter and mixture copula models, we favour models that are capable of generating upper tail dependence, that is, when several LoBs have a strong tendency to exhibit extreme losses simultaneously. We compare the selected models in their ability to quantify risks of multivariate portfolios. By performing an extensive investigation of the in- and out-of-sample Value-at-Risk (VaR) forecasts by analysing VaR exceptions (i.e. observations of realised portfolio value that are greater than the estimated VaR), we demonstrate that the selected models allow to reliably quantify portfolio risk. Our results provide valuable insights with regards to the nature of dependence and fulfils one of the primary objectives of the general insurance providers aiming at assessing total risk of an aggregate portfolio of losses when LoBs are correlated

Effects of Turbulent Mixing on the Critical Behavior

Effects of strongly anisotropic turbulent mixing on the critical behavior are studied by means of the renormalization group. Two models are considered: the equilibrium model A, which describes purely relaxational dynamics of a nonconserved scalar order parameter, and the Gribov model, which describes the nonequilibrium phase transition between the absorbing and fluctuating states in a reaction-diffusion system. The velocity is modelled by the d-dimensional generalization of the random shear flow introduced by Avellaneda and Majda within the context of passive scalar advection. Existence of new nonequilibrium types of critical regimes (universality classes) is established.Comment: Talk given in the International Bogolyubov Conference "Problems of Theoretical and Mathematical Physics" (Moscow-Dubna, 21-27 August 2009

Communication Platforms for Cities: Critical Analysis of Management Technology

Development of digital technologies creates opportunities for the implementation of new forms and innovative methods into the state management system. For a long time, public administration specialists have discussed vividly the idea of an electronic state (e-government), as well as have de bated the advantages and disadvantages of specific digital technologies. Recently, urban communication platforms have become very popular, which indicates that the involvement of citizens into the public administration processes. In recent years, there has been a transition from a model of simple informing and providing public services with digital format to a model of active involvement of citizens through the so-called state platforms. The idea of “the state as a platform” involves the creation of digital platforms to attract business and civil society to receive services, organize discussions and votes on various issues, as well as exchange goods created by both state and non-state producers. The article provides an overview and analysis of existing urban communication platforms in Russia and abroad. To this end, the article used the method of comparative analysis of urban communication platforms based on the criterion of functional features. It was found that today in Russia there are four types of urban communication platforms, which differ in their goals and functionality. The article substantiates the following typology: (1) platforms (sections of sites, pages) of citizens’ appeals; (2) portals of urban (regional) problems; (3) portals for evaluating initiatives; (4) public participation portals / platforms. Communication platforms have been created in all constituent entities of the Russian Federation, but the level of citizen participation in their activities varies greatly. The article analyzes the obstacles to the development of urban communication platforms

A compendium and functional characterization of mammalian genes involved in adaptation to Arctic or Antarctic environments

Many mammals are well adapted to surviving in extremely cold environments. These species have likely accumulated genetic changes that help them efficiently cope with low temperatures. It is not known whether the same genes related to cold adaptation in one species would be under selection in another species. The aims of this study therefore were: to create a compendium of mammalian genes related to adaptations to a low temperature environment; to identify genes related to cold tolerance that have been subjected to independent positive selection in several species; to determine promising candidate genes/pathways/organs for further empirical research on cold adaptation in mammals