19 research outputs found

    The chemical evolution of the solar neighbourhood

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    Recent models of galactic chemical evolution account for updated evolutionary models of massive stars (with special emphasis on stellar winds) and for the effects of intermediate mass and massive binaries. The results are summarised. We also present a critical discussion on possible effects of stellar rotation on overall galactic chemical evolutionary simulations.Comment: 12 pages, 3 figures, Pacific Rim Conference, Xi'an, China, 11-17 July 200

    Explosive Nucleosynthesis: What we learned and what we still do not understand

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    This review touches on historical aspects, going back to the early days of nuclear astrophysics, initiated by B2^2FH and Cameron, discusses (i) the required nuclear input from reaction rates and decay properties up to the nuclear equation of state, continues (ii) with the tools to perform nucleosynthesis calculations and (iii) early parametrized nucleosynthesis studies, before (iv) reliable stellar models became available for the late stages of stellar evolution. It passes then through (v) explosive environments from core-collapse supernovae to explosive events in binary systems (including type Ia supernovae and compact binary mergers), and finally (vi) discusses the role of all these nucleosynthesis production sites in the evolution of galaxies. The focus is put on the comparison of early ideas and present, very recent, understanding.Comment: 11 pages, to appear in Springer Proceedings in Physics (Proc. of Intl. Conf. "Nuclei in the Cosmos XV", LNGS Assergi, Italy, June 2018

    Observational Constraints on the Common Envelope Phase

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    The common envelope phase was first proposed more than forty years ago to explain the origins of evolved, close binaries like cataclysmic variables. It is now believed that the phase plays a critical role in the formation of a wide variety of other phenomena ranging from type Ia supernovae through to binary black holes, while common envelope mergers are likely responsible for a range of enigmatic transients and supernova imposters. Yet, despite its clear importance, the common envelope phase is still rather poorly understood. Here, we outline some of the basic principles involved, the remaining questions as well as some of the recent observational hints from common envelope phenomena - namely planetary nebulae and luminous red novae - which may lead to answering these open questions.Comment: 29 pages, 8 figures. To appear in the book "Reviews in Frontiers of Modern Astrophysics: From Space Debris to Cosmology" (eds. Kabath, Jones and Skarka; publisher Springer Nature) funded by the European Union Erasmus+ Strategic Partnership grant "Per Aspera Ad Astra Simul" 2017-1-CZ01-KA203-03556

    Rift Valley fever virus NSs protein functions and the similarity to other bunyavirus NSs proteins

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    The Nordic maintenance care program – case management of chiropractic patients with low back pain: A survey of Swedish chiropractors

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    <p>Abstract</p> <p>Background</p> <p>Chiropractic treatment for low back pain (LBP) can often be divided into two phases: Initial treatment of the problem to attempt to remove pain and bring it back into its pre-clinical or maximum improvement status, and "maintenance care", during which it is attempted to maintain this status. Although the use of chiropractic maintenance care has been described and discussed in the literature, there is no information as to its precise indications. The objective of this study is to investigate if there is agreement among Swedish chiropractors on the overall patient management for various types of LBP-scenarios, with a special emphasis on maintenance care.</p> <p>Method</p> <p>The design was a mailed questionnaire survey. Members of the Swedish Chiropractors' Association, who were participants in previous practice-based research, were sent a closed-end questionnaire consisting of nine case scenarios and six clinical management alternatives and the possibility to create one's own alternative, resulting in a "nine-by-seven" table. The research team defined its own pre hoc choice of "clinically logical" answers based on the team's clinical experience. The frequency of findings was compared to the suggestions of the research team.</p> <p>Results</p> <p>Replies were received from 59 (60%) of the 99 persons who were invited to take part in the study. A pattern of self-reported clinical management strategies emerged, largely corresponding to the "clinically logical" answers suggested by the research team. In general, patients of concern would be referred out for a second opinion, cases with early recovery and without a history of previous low back pain would be quickly closed, and cases with quick recovery and a history of recurring events would be considered for maintenance care. However, also other management patterns were noted, in particular in the direction of maintenance care.</p> <p>Conclusion</p> <p>To a reasonable extent, Swedish chiropractors participating in this survey appear to agree on the clinical management for different cases of LBP.</p
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