292 research outputs found

    Supernovae from rotating stars

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    The present paper discusses the main physical effects produced by stellar rotation on presupernovae, as well as observations which confirm these effects and their consequences for presupernova models. Rotation critically influences the mass of the exploding cores, the mass and chemical composition of the envelopes and the types of supernovae, as well as the properties of the remnants and the chemical yields. In the formation of gamma-ray bursts, rotation and the properties of rotating stars appear as the key factor. In binaries, the interaction between axial rotation and tidal effects often leads to interesting and unexpected results. Rotation plays a key role in shaping the evolution and nucleosynthesis in massive stars with very low metallicities (metallicity below about the Small Magellanic Cloud metallicity down to Population III stars). At solar and higher metallicities, the effects of rotation compete with those of stellar winds. In close binaries, the synchronisation process can lock the star at a high rotation rate despite strong mass loss and thus both effects, rotation and stellar winds, have a strong impact. In conclusion, rotation is a key physical ingredient of the stellar models and of presupernova stages, and the evolution both of single stars and close binaries. Moreover, important effects are expected along the whole cosmic history.Comment: 36 pages, 15 figures, published in Handbook of Supernovae, A.W. Alsabti and P. Murdin (eds), Springe

    Nonclassicality generated by photon annihilation-then-creation and creation-then-annihilation operations

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    We examine nonclassical properties of the field states generated by applying the photon annihilation-then-creation operation (AC) and creation-then-annihilation operation (CA) to the thermal and coherent states. Effects of repeated applications of AC and of CA are also studied. We also discuss experimental schemes to realize AC and CA with a cavity system using atom-field interactions.Comment: To be published in Journal of the Optical Society of America

    The Evolution of Compact Binary Star Systems

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    We review the formation and evolution of compact binary stars consisting of white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Binary NSs and BHs are thought to be the primary astrophysical sources of gravitational waves (GWs) within the frequency band of ground-based detectors, while compact binaries of WDs are important sources of GWs at lower frequencies to be covered by space interferometers (LISA). Major uncertainties in the current understanding of properties of NSs and BHs most relevant to the GW studies are discussed, including the treatment of the natal kicks which compact stellar remnants acquire during the core collapse of massive stars and the common envelope phase of binary evolution. We discuss the coalescence rates of binary NSs and BHs and prospects for their detections, the formation and evolution of binary WDs and their observational manifestations. Special attention is given to AM CVn-stars -- compact binaries in which the Roche lobe is filled by another WD or a low-mass partially degenerate helium-star, as these stars are thought to be the best LISA verification binary GW sources.Comment: 105 pages, 18 figure

    Home-based music therapy - a systematic overview of settings and conditions for an innovative service in healthcare

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    <p>Abstract</p> <p>Background</p> <p>Almost every Western healthcare system is changing to make their services more centered around out-patient care. In particular, long-term or geriatric patients who have been discharged from the hospital often require home-based care and therapy. Therefore, several programs have been developed to continue the therapeutic process and manage the special needs of patients after discharge from hospital. Music therapy has also moved into this field of healthcare service by providing home-based music therapy (HBMT) programs. This article reviews and summarizes the settings and conditions of HBMT for the first time.</p> <p>Methods</p> <p>The following databases were used to find articles on home-based music therapy: AMED, CAIRSS, EMBASE, MEDLINE, PsychINFO, and PSYNDEX. The search terms were "home-based music therapy" and "mobile music therapy". Included articles were analyzed with respect to participants as well as conditions and settings of HBMT. Furthermore, the date of publication, main outcomes, and the design and quality of the studies were investigated.</p> <p>Results</p> <p>A total of 20 international publications, 11 clinical studies and nine reports from practice, mainly from the United States (n = 8), were finally included in the qualitative synthesis. Six studies had a randomized controlled design and included a total of 507 patients. The vast majority of clients of HBMT are elderly patients living at home and people who need hospice and palliative care. Although settings were heterogeneous, music listening programs played a predominant role with the aim to reduce symptoms like depression and pain, or to improve quality of life and the relationship between patients and caregivers as primary endpoints.</p> <p>Conclusions</p> <p>We were able to show that HBMT is an innovative service for future healthcare delivery. It fits with the changing healthcare system and its conditions but also meets the therapeutic needs of the increasing number of elderly and severely impaired people. Apart from music therapists, patients and their families HBMT is also interesting as a blueprint for home based care for other groups of caregivers.</p

    Determinants of Unlawful File Sharing: A Scoping Review

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    We employ a scoping review methodology to consider and assess the existing evidence on the determinants of unlawful file sharing (UFS) transparently and systematically. Based on the evidence, we build a simple conceptual framework to model the psychological decision to engage in UFS, purchase legally or do nothing. We identify social, moral, experiential, technical, legal and financial utility sources of the decision to purchase or to file share. They interact in complex ways. We consider the strength of evidence within these areas and note patterns of results. There is good evidence for influences on UFS within each of the identified determinants, particularly for self-reported measures, with more behavioral research needed. There are also indications that the reasons for UFS differ across media; more studies exploring media other than music are required

    Strongly interacting polaritons in coupled arrays of cavities

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    Observing quantum phenomena in strongly correlated many-particle systems is difficult because of the short length- and timescales involved. Exerting control over the state of individual elements within such a system is even more so, and represents a hurdle in the realization of quantum computing devices. Substantial progress has been achieved with arrays of Josephson junctions and cold atoms in optical lattices, where detailed control over collective properties is feasible, but addressing individual sites remains a challenge. Here we show that a system of polaritons held in an array of resonant optical cavities—which could be realized using photonic crystals or toroidal microresonators—can form a strongly interacting many-body system showing quantum phase transitions, where individual particles can be controlled and measured. The system also offers the possibility to generate attractive on-site potentials yielding highly entangled states and a phase with particles much more delocalized than in superfluids

    Foot-and-Mouth Disease Virus Persists in the Light Zone of Germinal Centres

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    Foot-and-mouth disease virus (FMDV) is one of the most contagious viruses of animals and is recognised as the most important constraint to international trade in animals and animal products. Two fundamental problems remain to be understood before more effective control measures can be put in place. These problems are the FMDV “carrier state” and the short duration of immunity after vaccination which contrasts with prolonged immunity after natural infection. Here we show by laser capture microdissection in combination with quantitative real-time reverse transcription polymerase chain reaction, immunohistochemical analysis and corroborate by in situ hybridization that FMDV locates rapidly to, and is maintained in, the light zone of germinal centres following primary infection of naïve cattle. We propose that maintenance of non-replicating FMDV in these sites represents a source of persisting infectious virus and also contributes to the generation of long-lasting antibody responses against neutralising epitopes of the virus
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