6,853 research outputs found

    Superorbital Period in the High Mass X-ray Binary 2S 0114+650

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    We report the detection of a superorbital period in the high-mass X-ray binary 2S 0114+650. Analyses of data from the Rossi X-ray Timing Explorer (RXTE) All-Sky Monitor (ASM) from 1996 January 5 to 2004 August 25 reveal a superorbital period of 30.7 +/- 0.1 d, in addition to confirming the previously reported neutron star spin period of 2.7 h and the binary orbital period of 11.6 d. It is unclear if the superorbital period can be ascribed to the precession of a warped accretion disc in the system.Comment: 5 pages, 5 figures, submitted to MNRAS 27th January 2005. Manuscript expanded to include discussion of evolution of periods, and hardness ratio variability. Number of figures increased from 5 to 9. Accepted for publication 19th December 200

    A Multicoloured View of 2S 0114+650

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    We report the results of radio and X-ray observations of the high mass X-ray binary 2S 0114+650, made with the Giant Meterwave Radio Telescope and the Rossi X-ray Timing Explorer respectively. No emission was detected at radio wavelengths. The neutral hydrogen column density was found to vary over the orbital period, while no variability over the the super-orbital period was observed. We discuss the causes of the observed relationships and the implications for the underlying mechanisms.Comment: 4 pages, 2 figures; to appear in proceedings for "The multicoloured landscape of compact objects and their explosive progenitors", Cefalu, Sicily, 2006 June 11-24, AIP, submitte

    Topological Properties from Einstein's Equations?

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    In this work we propose a new procedure for to extract global information of a space-time. We considered a space-time immersed in a higher dimensional space and we formulate the equations of Einstein through of the Frobenius conditions to immersion. Through of an algorithm and the implementation into algebraic computing system we calculate normal vectors from the immersion to find out the second fundamental form. We make a application for space-time with spherical symmetry and static. We solve the equations of Einstein to the vacuum and we obtain space-times with different topologies.Comment: 7 pages, accepted for publication in Int. J. Mod. Phys.

    Embedding Versus Immersion in General Relativity

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    We briefly discuss the concepts of immersion and embedding of space-times in higher-dimensional spaces. We revisit the classical work by Kasner in which he constructs a model of immersion of the Schwarzschild exterior solution into a six-dimensional pseudo-Euclidean manifold. We show that, from a physical point of view, this model is not entirely satisfactory since the causal structure of the immersed space-time is not preserved by the immersion.Comment: 5 page

    Longevity and mortality in Kennel Club registered dog breeds in the UK in 2014

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    Abstract Background The domestic dog is one of the most diverse mammalian species, exhibiting wide variations in morphology, behaviour and morbidity across breeds. Therefore, it is not unexpected that breeds should also exhibit variation in mortality and longevity. While shorter longevity per se may not necessarily be a welfare issue, a generally foreshortened lifespan in a breed that is accompanied by a high prevalence of a particular cause of death may reveal potentially serious welfare concerns and highlight scope to improve breed welfare. Survey data gathered directly from owners offer useful insights into canine longevity and mortality that can support the overall evidence base for welfare reforms within breeds. Results Mortality data on 5663 deceased dogs registered with the UK Kennel Club were collected from an owner-based survey. The most commonly reported causes of death were old age (13.8%), unspecified cancer (8.7%) and heart failure (4.9%); with 5.1% of deaths reported as unknown cause. Overall median age at death was 10.33 years (interquartile range: 7.17–12.83 years). Breeds varied widely in median longevity overall from the West Highland Terrier (12.71 years) to the Dobermann Pinscher (7.67 years). There was also wide variation in the prevalence of some common causes of death among breeds, and in median longevity across the causes of death. Conclusion Substantial variation in the median lifespan and the prominent causes of death exists across breeds. This study has identified some breeds with both a low median lifespan and also a high proportional mortality for one or more specific causes of death that should be considered as both potential welfare concerns as well as opportunities for improvement

    Large-scale survey to estimate the prevalence of disorders for 192 Kennel Club registered breeds

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    Abstract Background Pedigree or purebred dogs are often stated to have high prevalence of disorders which are commonly assumed to be a consequence of inbreeding and selection for exaggerated features. However, few studies empirically report and rank the prevalence of disorders across breeds although such data are of critical importance in the prioritisation of multiple health concerns, and to provide a baseline against which to explore changes over time. This paper reports an owner survey that gathered disorder information on Kennel Club registered pedigree dogs, regardless of whether these disorders received veterinary care. This study aimed to determine the prevalence of disorders among pedigree dogs overall and, where possible, determine any variation among breeds. Results This study included morbidity data on 43,005 live dogs registered with the Kennel Club. Just under two thirds of live dogs had no reported diseases/conditions. The most prevalent diseases/conditions overall were lipoma (4.3%; 95% confidence interval 4.13-4.52%), skin (cutaneous) cyst (3.1%; 2.94-3.27%) and hypersensitivity (allergic) skin disorder (2.7%; 2.52-2.82%). For the most common disorders in the most represented breeds, 90 significant differences between the within breed prevalence and the overall prevalence are reported. Conclusion The results from this study have added vital epidemiological data on disorders in UK dogs. It is anticipated that these results will contribute to the forthcoming Breed Health & Conservation Plans, a Kennel Club initiative aiming to assist in the identification and prioritisation of breeding selection objectives for health and provide advice to breeders/owners regarding steps that may be taken to minimise the risk of the disease/disorders. Future breed-specific studies are recommended to report more precise prevalence estimates within more breeds

    Recurrent ~24 h Periods in RXTE ASM Data

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    Analysis of data from the Rossi X-ray Timing Explorer satellite's All Sky Monitor instrument for several X-ray binary sources has identified a recurrent \~24 h period. This period is sometimes highly significant, giving rise to the possibility of it being identified as an orbital or super-orbital period. Further analysis has revealed the same period in a number of other X-ray sources. As a result this period has been discounted as spurious, described variously as arising from daily variations in background levels and beating between the sampling period and long-term secular trends in the light curves. We present here an analysis of the spurious periods and show that the dominant mechanism is in fact spectral leakage of low-frequency power present in the light curves.Comment: 9 Pages, 10 figures, 1 table, submitted to PASA 20th December 2004. Added 1 page of text and 3 figures to clarify results and discussion. Resubmitted 16th May 2005. Accepted 25th June 200

    Using creative writing to explore facilitation skills in practice

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    Background: Facilitation skills are key to the effective use of practice development strategies. Students on a Masters in Practice Development and Innovation undertake a module on Facilitation skills which incorporates the use of a creative writing piece to explore facilitation. The aim of this article is to critically reflect on the use of creative writing within an assignment from the lecturer perspective. Critical Reflection: Rolfe et al (2001) model of reflection will be utilised to structure the reflections, considering the questions ‘What?’, ‘So What?’ and ‘Now What?’. This will discuss the concerns about the assessment method, student thoughts, relationship to practice development and evidence of effectiveness of the strategy. Examples of creative writing from the students will be used to demonstrate the diversity of the approach. Ethics: All students have given permission for their work to be included Discussion: Using creative writing can be freeing for students as they can use their voice to explore a topic. For the lecturer courage is needed to facilitate this expression but is rewarding as links to the principles of practice development to embed new ways of working. Important within the process is the need to give students ‘permission’ to utilise a non-traditional style of writing and the lecturer may benefit from practising the technique themselves to feel comfortable with the creative writing strategy. Conclusion: Creative writing enabled an opportunity to explore facilitation in different ways and relate to different aspects of real and imagined life. This paper shows that creative writing can be used successfully by students to engage in novel ways of thinking. However, future actions identify the importance of guidance regarding relevance to academia and ensuring the lecturer is familiar with the aim and techniques of the process when using it for Masters level assessment
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