93 research outputs found

    No-horizon theorem for spacetimes with spacelike G1 isometry groups

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    We consider four-dimensional spacetimes (M,g)(M,{\mathbf g}) which obey the Einstein equations G=T{\mathbf G}={\mathbf T}, and admit a global spacelike G1=RG_{1}={\mathbb R} isometry group. By means of dimensional reduction and local analyis on the reduced (2+1) spacetime, we obtain a sufficient condition on T{\mathbf T} which guarantees that (M,g)(M,{\mathbf g}) cannot contain apparent horizons. Given any (3+1) spacetime with spacelike translational isometry, the no-horizon condition can be readily tested without the need for dimensional reduction. This provides thus a useful and encompassing apparent horizon test for G1G_{1}-symmetric spacetimes. We argue that this adds further evidence towards the validity of the hoop conjecture, and signals possible violations of strong cosmic censorship.Comment: 8 pages, LaTeX, uses IOP package; published in Class. Quantum Gra

    Habitable Zones in the Universe

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    Habitability varies dramatically with location and time in the universe. This was recognized centuries ago, but it was only in the last few decades that astronomers began to systematize the study of habitability. The introduction of the concept of the habitable zone was key to progress in this area. The habitable zone concept was first applied to the space around a star, now called the Circumstellar Habitable Zone. Recently, other, vastly broader, habitable zones have been proposed. We review the historical development of the concept of habitable zones and the present state of the research. We also suggest ways to make progress on each of the habitable zones and to unify them into a single concept encompassing the entire universe.Comment: 71 pages, 3 figures, 1 table; to be published in Origins of Life and Evolution of Biospheres; table slightly revise

    Circumstellar disks and planets. Science cases for next-generation optical/infrared long-baseline interferometers

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    We present a review of the interplay between the evolution of circumstellar disks and the formation of planets, both from the perspective of theoretical models and dedicated observations. Based on this, we identify and discuss fundamental questions concerning the formation and evolution of circumstellar disks and planets which can be addressed in the near future with optical and infrared long-baseline interferometers. Furthermore, the importance of complementary observations with long-baseline (sub)millimeter interferometers and high-sensitivity infrared observatories is outlined.Comment: 83 pages; Accepted for publication in "Astronomy and Astrophysics Review"; The final publication is available at http://www.springerlink.co

    A study of home deaths in Japan from 1951 to 2002

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    BACKGROUND: Several surveys in Japan have indicated that most terminally ill Japanese patients would prefer to die at home or in a homelike setting. However, there is a great disparity between this stated preference and the reality, since most Japanese die in hospital. We report here national changes in home deaths in Japan over the last 5 decades. Using prefecture data, we also examined the factors in the medical service associated with home death in Japan. METHODS: Published data on place of death was obtained from the vital statistics compiled by the Ministry of Health, Labor and Welfare of Japan. We analyzed trends of home deaths from 1951 to 2002, and describe the changes in the proportion of home deaths by region, sex, age, and cause of death. Joinpoint regression analysis was used for trend analysis. Logistic regression analysis was performed to identify secular trends in home deaths, and the impact of age, sex, year of deaths and cause of deaths on home death. We also examined the association between home death and medical service factors by multiple regression analysis, using home death rate by prefectures in 2002 as a dependent variable. RESULTS: A significant decrease in the percentage of patients dying at home was observed in the results of joinpoint regression analysis. Older patients and males were more likely to die at home. Patients who died from cancer were less likely to die at home. The results of multiple regression analysis indicated that home death was related to the number of beds in hospital, ratio of daily occupied beds in general hospital, the number of families in which the elderly were living alone, and dwelling rooms. CONCLUSION: The pattern of the place of death has not only been determined by social and demographic characteristics of the decedent, but also associated with the medical service in the community

    Barriers and drivers of public engagement in palliative care, Scoping review

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    Background The integral model of Palliative Care recognizes the community as essential element in improving quality of life of patients and families. It is necessary to find a formula that allows the community to have a voice. The aim of this scoping review is to identify barriers and facilitators to engage community in PC.Methods Systematic search was conducted in NICE, Cochrane Library, Health Evidence, CINAHL and PubMed database. Keywords: Palliative care, End of life care, community networks, community engagement, public engagement, community participation, social participation, barriers and facilitators.Results Nine hundred seventy-one results were obtained. Search strategy and inclusion criteria yielded 13 studies that were read in detail to identify factors influencing community engagement in palliative care, categorized into: Public health and public engagement; Community attitudes towards palliative care, death and preferences at the end of life; Importance of volunteers in public engagement programs; Compassionate communities.Conclusion Societal awareness must be a facilitated process to catalyse public engagement efforts. National policy initiatives and regional system support provide legitimacy and focus is essential for funding. The first step is to get a sense of what is important to society, bearing in mind cultural differences and to channel those aspects through health care professionals; connecting the most assistential part with community resources. The process and long-term results need to be systematically evaluated

    Barriers and drivers of public engagement in palliative care, Scoping review

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    Background The integral model of Palliative Care recognizes the community as essential element in improving quality of life of patients and families. It is necessary to find a formula that allows the community to have a voice. The aim of this scoping review is to identify barriers and facilitators to engage community in PC.Methods Systematic search was conducted in NICE, Cochrane Library, Health Evidence, CINAHL and PubMed database. Keywords: Palliative care, End of life care, community networks, community engagement, public engagement, community participation, social participation, barriers and facilitators.Results Nine hundred seventy-one results were obtained. Search strategy and inclusion criteria yielded 13 studies that were read in detail to identify factors influencing community engagement in palliative care, categorized into: Public health and public engagement; Community attitudes towards palliative care, death and preferences at the end of life; Importance of volunteers in public engagement programs; Compassionate communities.Conclusion Societal awareness must be a facilitated process to catalyse public engagement efforts. National policy initiatives and regional system support provide legitimacy and focus is essential for funding. The first step is to get a sense of what is important to society, bearing in mind cultural differences and to channel those aspects through health care professionals; connecting the most assistential part with community resources. The process and long-term results need to be systematically evaluated

    Live well, die well – an international cohort study on experiences, concerns and preferences of patients in the last phase of life: the research protocol of the iLIVE study

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    Introduction Adequately addressing the needs of patients at the end of life and their relatives is pivotal in preventing unnecessary suffering and optimising their quality of life. The purpose of the iLIVE study is to contribute to high-quality personalised care at the end of life in different countries and cultures, by investigating the experiences, concerns, preferences and use of care of terminally ill patients and their families. Methods and analysis The iLIVE study is an international cohort study in which patients with an estimated life expectancy of 6 months or less are followed up until they die. In total, 2200 patients will be included in 11 countries, that is, 200 per country. In addition, one relative per patient is invited to participate. All participants will be asked to fill in a questionnaire, at baseline and after 4 weeks. If a patient dies within 6 months of follow-up, the relative will be asked to fill in a post-bereavement questionnaire. Healthcare use in the last week of life will be evaluated as well; healthcare staff who attended the patient will be asked to fill in a brief questionnaire to evaluate the care that was provided. Qualitative interviews will be conducted with patients, relatives and healthcare professionals in all countries to gain more in-depth insights. Ethics and dissemination The cohort study has been approved by ethics committees and the institutional review boards (IRBs) of participating institutes in all countries. Results will be disseminated through the project website, publications in scientific journals and at conferences. Within the project, there will be a working group focusing on enhancing the engagement of the community at large with the reality of death and dying. Trial registration number NCT04271085

    Exploring new physics frontiers through numerical relativity

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    The demand to obtain answers to highly complex problems within strong-field gravity has been met with significant progress in the numerical solution of Einstein's equations - along with some spectacular results - in various setups. We review techniques for solving Einstein's equations in generic spacetimes, focusing on fully nonlinear evolutions but also on how to benchmark those results with perturbative approaches. The results address problems in high-energy physics, holography, mathematical physics, fundamental physics, astrophysics and cosmology

    Clinical significance of HIV-1 coreceptor usage

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    The identification of phenotypically distinct HIV-1 variants with different prevalence during the progression of the disease has been one of the earliest discoveries in HIV-1 biology, but its relevance to AIDS pathogenesis remains only partially understood. The physiological basis for the phenotypic variability of HIV-1 was elucidated with the discovery of distinct coreceptors employed by the virus to infect susceptible cells. The role of the viral phenotype in the variable clinical course and treatment outcome of HIV-1 infection has been extensively investigated over the past two decades. In this review, we summarize the major findings on the clinical significance of the HIV-1 coreceptor usage
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