207,253 research outputs found

    Models of Vortices and Spirals in White Dwarf's Accretion Binaries

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    The main aim in the current survey is to suggest models of the development of structures, such as vortices and spirals, in accretion white dwarf's binaries. Numerical methods and simulations are applied on the bases of hydrodynamic analytical considerations. It is suggested in the theoretical model the perturbation's parameters of the accretion flow, which are caused by the influences of the tidal wave over the flux of accretion matter around the secondary star. The results of numerical code application on the disturbed flow reveal an appearing of structure with spiral shape due to the tidal interaction in the close binaries. Our further simulations give the solution, which expresses the formation of vortical configurations in the accretion disc's zone. The evolution of vortices in areas of the flow's interaction is explored using single vortex and composite vortex models. Gas in the disc matter is considered to be compressible and non-ideal. The longevity of all these structures is different and each depends on the time period of the rotation, density and velocity of the accretion matter.Comment: 4 page

    TichĂ˝ and Fictional Names

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    The paper examines two possible analyses of fictional names within Pavel Tichý’s Transparent Intensional Logic. The first of them is the analysis actually proposed by Tichý in his (1988) book The Foundations of Frege’s Logic. He analysed fictional names in terms of free variables. I will introduce, explain, and assess this analysis. Subsequently, I will explain Tichý’s notion of individual role (office, thing-to-be). On the basis of this notion, I will outline and defend the second analysis of fictional names. This analysis is close to the approach known in the literature as role realism (the most prominent advocates of this position are Nicholas Wolterstorff, Gregory Currie, and Peter Lamarque)

    The Front Lines: Employer Provided Paid Parental Leave in the United States

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    [Excerpt] Parental leave has largely remained undiscussed in the United States since the late 1980s to early 1990s. The enactment of the Family and Medical Leave Act of 1993, which gave parents twelve weeks of unpaid parental leave, seemed to satiate scholarly writers. Encouragingly, the topic of parental leave has had a resurgence within the last election cycle. This article discusses the advances that employers are making to privately provide paid parental leave to their employees, the impact that makes on the employees, and explores the possibility of expanding the Family and Medical Leave Act to a paid parental leave policy. The United States has historically lagged behind other countries when it comes to parental leave policies, considering other countries began creating parental leave policies in the 1940s and 1950s after World War II. The United States continues to lag behind, as it is the only developed country that relies entirely on the private sector to provide paid parental leave

    On the Benefits of Partial Channel State Information for Repetition Protocols in Block Fading Channels

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    This paper studies the throughput performance of HARQ (hybrid automatic repeat request) protocols over block fading Gaussian channels. It proposes new protocols that use the available feedback bit(s) not only to request a retransmission, but also to inform the transmitter about the instantaneous channel quality. An explicit protocol construction is given for any number of retransmissions and any number of feedback bits. The novel protocol is shown to simultaneously realize the gains of HARQ and of power control with partial CSI (channel state information). Remarkable throughput improvements are shown, especially at low and moderate SNR (signal to noise ratio), with respect to protocols that use the feedback bits for retransmission request only. In particular, for the case of a single retransmission and a single feedback bit, it is shown that the repetition is not needed at low \snr where the throughput improvement is due to power control only. On the other hand, at high SNR, the repetition is useful and the performance gain comes form a combination of power control and ability of make up for deep fades.Comment: Accepted for publication on IEEE Transactions on Information Theory; Presented in parts at ITW 2007 and ICC 200

    Activation and radiation damage in the environment of hadron accelerators

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    A component which suffers radiation damage usually also becomes radioactive, since the source of activation and radiation damage is the interaction of the material with particles from an accelerator or with reaction products. However, the underlying mechanisms of the two phenomena are different. These mechanisms are described here. Activation and radiation damage can have far-reaching consequences. Components such as targets, collimators, and beam dumps are the first candidates for failure as a result of radiation damage. This means that they have to be replaced or repaired. This takes time, during which personnel accumulate dose. If the dose to personnel at work would exceed permitted limits, remote handling becomes necessary. The remaining material has to be disposed of as radioactive waste, for which an elaborate procedure acceptable to the authorities is required. One of the requirements of the authorities is a complete nuclide inventory. The methods used for calculation of such inventories are presented, and the results are compared with measured data. In the second part of the paper, the effect of radiation damage on material properties is described. The mechanism of damage to a material due to irradiation is described. The amount of radiation damage is quantified in terms of displacements per atom. Its calculation and deficiencies in explaining and predicting the changes in mechanical and thermal material properties are discussed, and examples are given.Comment: 27 pages, contribution to the CAS - CERN Accelerator School: Course on High Power Hadron Machines; 24 May - 2 Jun 2011, Bilbao, Spai

    Long-term Care in Romania. ENEPRI Research Report No. 85, 15 June 2010

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    Launched in January 2009, ANCIEN is a research project that runs for a 44-month period and involves 20 partners from EU member states. The project principally concerns the future of long-term care (LTC) for the elderly in Europe and addresses two questions in particular: 1) How will need, demand, supply and use of LTC develop? 2) How do different systems of LTC perform? This case study on Romania is part of the first stage in the project aimed at collecting the basic data and necessary information to portray long-term care in each country of the EU. It will be followed by analysis and projections of future scenarios on long-term care needs, use, quality assurance and system performance. State-of-the-art demographic, epidemiologic and econometric modelling will be used to interpret and project needs, supply and use of long-term care over future time periods for different LTC systems

    Integrating Conflicting Perspectives

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    "Theory of mind� describes the ability to impute mental states, such as beliefs, desires and intentions, to oneself and to other people. Usually we want to know why people did what they did and we wonder what they are going to do next. That is, everyday we try to predict and explain human behaviour. In order to do this we refer to a person"s beliefs, desires, emotions, intentions etc. Behaviour is the product of belief and desire: People do things because they desire something and believe some act will achieve it. For adults it is clear that our assumptions about reality do not necessarily match the real world; but we know, regardless of whether our beliefs are true or not, our beliefs direct our actions. In contrast, it is not until the age of 4 years that children understand that one can be mistaken about the world and that actions can be based on this false belief
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