1,017 research outputs found
Rotational kinetics of absorbing dust grains in neutral gas
We study the rotational and translational kinetics of massive particulates
(dust grains) absorbing the ambient gas. Equations for microscopic phase
densities are deduced resulting in the Fokker-Planck equation for the dust
component. It is shown that although there is no stationary distribution, the
translational and rotational temperatures of dust tend to certain values, which
differ from the temperature of the ambient gas. The influence of the inner
structure of grains on rotational kinetics is also discussed.Comment: REVTEX4, 20 pages, 2 figure
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Excess of loss reinsurance under joint survival optimality
Explicit expressions for the probability of joint survival up to time x of the cedent and the reinsurer, under an excess of loss reinsurance contract with a limiting and a retention level are obtained, under the reasonably general assumptions of any non-decreasing premium income function, Poisson claim arrivals and continuous claim amounts, modelled by any joint distribution. By stating appropriate optimality problems, we show that these results can be used to set the limiting and the retention levels in an optimal way with respect to the probability of joint survival. Alternatively, for fixed retention and limiting levels, the results yield an optimal split of the total premium income between the two parties in the excess of loss contract. This methodology is illustrated numerically on several examples of independent and dependent claim severities. The latter are modelled by a copula function. The effect of varying its dependence parameter and the marginals, on the solutions of the optimality problems and the joint survival probability, has also been explored
On costa variation in leaves of fossil permian protoshagnalean mosses
Leaves of extinct mosses of the order Protosphagnales are studied with the special attention to their different developmental stages. A previously unknown morphotypes without costa and with very short costa are revealed in this group. It is characteristic for young small leaves of Kosjunia and Intia , but apparently does not occur in other genera of this fossil order. The present collection allows restore a heteroblastic series in these leaves and associated with it differentiation of laminal areolationyesBelgorod State National Research Universit
Complex of methodical means of formation of ecological and legal competence of university students in the process of natural sciences education
The aim of the investigation is to present the ways and a technique of formation of students’ ecological and legal competence at humanities departments of high schools in the course of studying of natural sciences. Methods and results. Having applied the methods of pedagogical modelling and using resources of natural-science disciplines, the author has developed a new complex based on structure and maintenance of the methodical tools that is directed at ecological and legal competence of high school students. Substantial block of the complex includes the integrated training course «Modern scientific picture of the world», supporting elective courses and interdisciplinary modules of eco-cultural orientation. Implementing ideas and cognitive models of postnonclassical science (systems theory, self-organization and organization) enables to provide an approach to describe the natural sciences and the social and cultural world with unified methodological positions, to build a complete system-synergetic picture in which the life of animate and inanimate nature, human life and work and society are inseparable single thread. The general laws of self-organization and evolution of complicated systems taught in the basic course enable to identify the similarities and differences in the dynamics of natural and social processes, face the problem of ecological culture and ethical and legal mechanisms, to regulate human activity that enhances deontological content of natural science training. The technology block of the educational complex includes technology and teaching methods, which combine traditional and innovative forms of the organization of educational process. «Case studies» technology is proposed as a productive tool for developing ecological and legal competence. This technology successfully integrates many of the current well-known methods and forms of education, promoting the implementation of the competency approach. Scientific novelty and practical significance. The results of the diagnostic research presented in the paper show that the use of the proposed educational complex enriches the eco-cultural knowledge of students, contributes to encouraging them to master natural science area, and is an effective tool in formation of ecological and legal competence. Testing the complex in the training process among different categories of students gives grounds to conclude that it can be wider used in educational practice Цель публикации – показать способы и методику становления эколого-правовой компетентности у студентов гуманитарных подразделений вузов в процессе изучения естественных наук. Методы и результаты. Применив методы педагогического моделирования и используя ресурсы естественнонаучных дисциплин, автор разработал новый по структуре и содержанию комплекс методических средств, развивающих эколого-правовую компетентность у студентов вуза. Содержательный блок комплекса включает основной интегрированный учебный курс «Современная научная картина мира», поддерживающие его элективные курсы и междисциплинарные модули экокультурной направленности. Реализация в их содержании идей и познавательных моделей постнеклассической науки (теории систем, самоорганизации и организации) позволяет описысывать естественнонаучную и социокультурную картины мира с единых методологических позиций, выстраивать целостные системно-синергетические представления, согласно которым жизнь неживой и живой природы, жизнь и деятельность человека и общества нерасторжимо связаны. Раскрытые в основном курсе общие закономерности процессов самоорганизации и эволюции сложных систем, демонстрируют сходство и различие в динамике природных и социальных процессов, дают возможность выйти на проблемы экологической культуры и этико-правовых механизмов регулирования деятельности человека, что усиливает деонтологическую (этико-правовую) составляющую содержания естественнонаучной подготовки. Процессуальный блок комплекса включает технологии и методы обучения, органично сочетающие традиционные и инновационные формы организации учебного процесса. В качестве одного из продуктивных инструментов формирования эколого-правовой компетентности предлагается технология «кейс-стади». В ее структуру успешно вписываются многие известные сегодня методы и формы обучения, способствующие реализации компетентностного подхода. Научная новизна и практическая значимость. Приведенные в статье результаты диагностических исследований подтверждают, что использование предложенного комплекса обогащает экокультурное пространство студентов, способствует развитию у них мотивации самостоятельного пополнения естественнонаучных знаний и является действенным инструментом формирования эколого-правовой компетентности. Опробование комплекса на разных категориях обучающихся дает основание сделать вывод о возможности более широкого его применения в образовательной практик
Formation of ecology and law competence at students of university in the natural science education
The problem of formation of ecology and the legal competence of students of humanities training in university during their science education. Author proposes to develop a system of teaching tools to solve it with the assistance of resource ecological ethicsВ статье рассматривается проблема формирования эколого-правовой компетентности студентов гуманитарных направлений подготовки в вузе в процессе их естественнонаучного образования. Предлагается разработанная автором система методических средств ее решения с привлечением ресурса экологической деонтологи
Ten plant species most commonly used in the form of tea and plant food supplements in Bulgaria
The use of plants to maintain health is one of the most ancient methods in the world and in our country. A large number of plant species are used based on their traditional use. Literature data show that people use plant products to maintain their health in the form of teas, juices, plant medicinal products, plant food supplements, etc. The purpose of this publication is to study the plant species most commonly used in 2016 in the form of plant products (PP) - (PFS[1], teas[2])[3] which are intended to be purchased without medical prescription and observation by participants in a cross-sectional survey study (2017), which is the first of its kind in Bulgaria. The cross-sectional survey study has been conducted with 400 individuals (N=400) aged 18-80 years who have expressed willingness and consent to complete a worked out questionnaire with anonymity guaranteed. The methods used are: a sociological method - direct individual paper survey cards, a documentary method. The statistical analysis of the data from survey cards has been performed using SPSS 20.0 statistical package. The results of the study performed show that the ten plant species most commonly used by the respondents in a descending order in the form of tea are: valerian (Valeriana officinalis L.), camomile (Matricaria chamomilla L.), linden (Tilia), ginkgo biloba (Ginkgo biloba L), black elder (Sambucus nigra L.), peppermint (Mentha piperita L.), thyme (Thymus serpyllum L.), rosehip (Rosa canina L.), senna (Cassia angustifolia Vahl.), and in the form of plant food supplements are: valerian (Valeriana officinalis L.), camomile (Matricaria chamomilla L.), ginkgo biloba (Ginkgo biloba L), linden (Tilia), St. John's Wort (Hypericum perforatum L.), black elder (Sambucus nigra L.), thyme (Thymus serpyllum L.), bearberry (Arctostaphylos uva-ursi L.), rosehip (Rosa canina L.), lavender (Lavandula angustifolia Mill.). Valerian (Valeriana officinalis L.) is the plant species most commonly used by the respondents both in the form of tea and PFS. Keywords: ten most commonly used plants, tea, plant food supplement, Bulgarian consumers [1] Plant Food Supplements – foods that aim to complement the normal diet, which contain plants, parts and extracts of plants. PFS are offered in the form of capsules, tablets, pills and others such as powder sachets, ampoules of liquids, drops and other similar forms, intended for taking in small unit quantities, intended for use without doctor’s prescription and observation (Garcia-Alvares, A. et al, 2014) [2] Tea – water extract obtained by boiling or steaming of dried parts of plants or whole plants [3] Within the meaning of this stud
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Ruin and Deficit Under Claim Arrivals with the Order Statistics Property
We consider an insurance risk model with extended flexibility,
under which claims arrive according to a point process with an order
statistics (OS) property, their amounts may have any joint distri-
bution and the premium income is accumulated following any non-
decreasing, possibly discontinuous real valued function. We generalize the definition of an OS point process, assuming it is generated by an arbitrary cdf allowing jump discontinuities, which corresponds to an arbitrary (possibly discontinuous) claim arrival cumulative intensity function. The latter feature is appealing for insurance applications since it allows to consider clusters of claims arriving instantaneously. Under these general assumptions, a closed form expression for the joint distribution of the time to ruin and the deficit at ruin is derived, which remarkably involves classical Appell polynomials. Corollaries of our main result generalize previous non-ruin formulas e.g., those obtained by Ignatov and Kaishev (2000, 2004, 2006) and Lef`evre and Loisel (2009) for the case of stationary Poisson claim arrivals and by Lef`evre and Picard (2011, 2014), for OS claim arrivals
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Operational risk and insurance: a ruin probabilistic reserving approach
A new methodology for financial and insurance operational risk capital estimation is proposed. It is based on using the finite time probability of (non-)ruin as an operational risk measure, within a general risk model. It allows for inhomogeneous operational loss frequency (dependent inter-arrival times) and dependent loss severities which may have any joint discrete or continuous distribution. Under the proposed methodology, operational risk capital assessment is viewed not as a one off exercise, performed at some moment of time, but as dynamic reserving, following a certain risk capital accumulation function. The latter describes the accumulation of risk capital with time and may be any nondecreasing, mpositive real function hHtL. Under these reasonably general assumptions, the probability of mnon-ruin is explicitly expressed using closed form expressions, derived by Ignatov and Kaishev (2000, 2004, 2007) and Ignatov, Kaishev and Krachunov (2001) and by setting it to a high enough preassigned mvalue, say 0.99, it is possible to obtain not just a value for the capital charge but a (dynamic) risk capital accumulation strategy, hHtL. In view of its generality, the proposed methodology is capable of accommodating any (heavy tailed) mdistributions, such as the Generalized Pareto Distribution, the Lognormal distribution the g-and-h mdistribution and the GB2 distribution. Applying this methodology on numerical examples, we demonstrate that dependence in the loss severities may have a dramatic effect on the estimated risk capital. In addition, we show also that one and the same high enough survival probability may be achieved by mdifferent risk capital accumulation strategies one of which may possibly be preferable to accumulating capital just linearly, as has been assumed by Embrechts et al. (2004). The proposed methodology takes into account also the effect of insurance on operational losses, in which case it is proposed to take the probability of joint survival of the financial institution and the insurance provider as a joint operational risk measure. The risk capital allocation strategy is then obtained in such a way that the probability of joint survival is equal to a preassigned high enough value, say 99.9
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