1,640 research outputs found

    Imaging the transition between pre-planetary and planetary nebulae: : Integral Field Spectroscopy of hot post-AGB stars with NIFS

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    This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record [T. M. Gledhill, and K. P. Forde, 'Imaging the transition between pre-planetary and planetary nebulae: integral field spectroscopy of hot post-AGB stars with NIFS', MNRAS, Vol. 447 (2): 1080-1095, February 2015] is available online at: https://doi.org/10.1093/mnras/stu2493.We present 2 to 2.4 micron integral field spectroscopy of a sample of hot post-AGB stars with early-B spectral types, using the NIFS instrument on Gemini North. These stars are just beginning to ionize their immediate environments and turn into planetary nebulae (PNe).We use molecular hydrogen emission lines together with hydrogen and helium recombination lines to explore the distribution of molecular and atomic gas and the extent of the developing ionized region. We see a range of evolutionary stages: IRAS 18062+2410 and IRAS 18379-1707 have recently developed compact and unresolved regions of photoionized H within axisymmetric molecular envelopes, with the former object increasing its Br-Gamma flux by a factor of 5.3 in 14 years; IRAS 22023+5249 and IRAS 20462+3416 have extended Br-Gamma nebulae and in the latter object only weak H2 emission remains; IRAS 19336-0400 is at a more advanced stage of PN formation where H2 is mostly dissociated and we see structure in both the H and He recombination line nebulae. IRAS 19200+3457 is the only object not to show the He I line at 2.058 micron and is probably the least evolved object in our sample; the H2 emission forms a ring around the star and we suggest that this object may be a rare example of a "round" pre-PN in transition to a "round" PN.Peer reviewedFinal Accepted Versio

    Alternative perspectives on school exclusion

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    This thesis explores, from non-standard, alternative perspectives, the subject of the permanent exclusion of children from school, especially avoidable exclusions. I discuss my work as a teacher and educational psychologist, a witness to and actor in this recurring phenomenon. I have considerable experience to draw from. Bearing witness to so many exclusions has proven challenging, bringing with it emotional cost. I cite research that reveals the extent of the school exclusion problem, research that is impotent in terms of promoting much-needed change. In pursuit of reason I go in new directions, exploring the works of four philosophers, using their insights as tools to explore the void between theory and practice, logic and reason; and how we want things to be and the reality of how things are for our most vulnerable children. Permanent exclusion from school is a complex social event the incidence rate of which is obfuscated by the agencies of school, local authority and government. I expose the numbers fiasco, which disguises the magnitude of the problem. The number of children formally excluded is, I argue, massaged downwards, the number informally excluded is concealed. The most vulnerable children are disproportionately affected and their voices rarely heard. We who contribute to these acts of exclusion do so dogmatically, ignorantly and blindly. Our role in the matter remains concealed even from ourselves. This thesis examines that role. Exclusion from school continues with machine-like regularity - something is driving it. To make an emotional connection with the subject matter I use the qualitative tools of personal reflection and fictional stories, the latter using a method inspired by Clough (2002). I address two research questions. I evaluate my study using the criteria suggested by Yardley (2000)

    Undergraduate teaching on biological weapons and bioterrorism at medical schools in the UK and the Republic of Ireland: results of a cross-sectional study

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    Objective To determine if individual undergraduate schools of medicine in the UK and the Republic of Ireland provide any teaching to medical students about biological weapons, bioterrorism, chemical weapons and weaponised radiation, if they perceive them to be relevant issues and if they figure them in their future plans. Design A cross-sectional study utilising an internet-based questionnaire sent to key figures responsible for leading on the planning and delivery of undergraduate medical teaching at all schools of medicine in the UK and Ireland. Setting All identified undergraduate schools of medicine in the UK and Ireland between August 2012 and December 2012. Outcome measures Numerical data and free text feedback about relevant aspects of undergraduate teaching. Results Of the 38 medical schools approached, 34 (28 in UK, 6 in Ireland) completed the questionnaire (89.47%). 4 (all in UK) chose not to complete it. 6/34 (17.65%) included some specific teaching on biological weapons and bioterrorism. 7/34 (20.59%) had staff with bioterrorism expertise (mainly in microbiological and syndromic aspects). 4/34 (11.76%) had plans to introduce some specific teaching on bioterrorism. Free text responses revealed that some felt that because key bodies (eg, UK's General Medical Council) did not request teaching on bioterrorism, then it should not be included, while others regarded this field of study as a postgraduate subject and not appropriate for undergraduates, or argued that the curriculum was too congested already. 4/34 (11.76%) included some specific teaching on chemical weapons, and 3/34 (8.82%) on weaponised radiation. Conclusions This study provides evidence that at the present time there is little teaching at the undergraduate level in the UK and Ireland on the subjects of biological weapons and bioterrorism, chemical weapons and weaponised radiation and signals that this situation is unlikely to change unless there were to be high-level policy guidance

    The brightest pure-H ultracool white dwarf

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    We report the identification of LSR J0745+2627 in the United Kingdom InfraRed Telescope Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS) as a cool white dwarf with kinematics and age compatible with the thick-disk/halo population. LSR J0745+2627 has a high proper motion (890 mas/yr) and a high reduced proper motion value in the J band (H_J=21.87). We show how the infrared-reduced proper motion diagram is useful for selecting a sample of cool white dwarfs with low contamination. LSR J0745+2627 is also detected in the Sloan Digital Sky Survey (SDSS) and the Wide-field Infrared Survey Explorer (WISE). We have spectroscopically confirmed this object as a cool white dwarf using X-Shooter on the Very Large Telescope. A detailed analysis of its spectral energy distribution reveals that its atmosphere is compatible with a pure-H composition model with an effective temperature of 3880+-90 K. This object is the brightest pure-H ultracool white dwarf (Teff<4000 K) ever identified. We have constrained the distance (24-45 pc), space velocities and age considering different surface gravities. The results obtained suggest that LSR J0745+2627 belongs to the thick-disk/halo population and is also one of the closest ultracool white dwarfs.Comment: 5 pages, 7 figures, accepted for publication in A&A Letter

    The effect of exogenous glucose infusion on early embryonic development in lactating dairy cows

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    peer-reviewedThe objective of this study was to examine the effect of intravenous infusion of glucose on early embryonic development in lactating dairy cows. Nonpregnant, lactating dairy cows (n = 12) were enrolled in the study (276 ± 17 d in milk). On d 7 after a synchronized estrus, cows were randomly assigned to receive an intravenous infusion of either 750 g/d of exogenous glucose (GLUC; 78 mL/h of 40% glucose wt/vol) or saline (CTRL; 78 mL/h of 0.9% saline solution). The infusion period lasted 7 d and cows were confined to metabolism stalls for the duration of the study. Coincident with the commencement of the infusion on d 7 after estrus, 15 in vitro-produced grade 1 blastocysts were transferred into the uterine horn ipsilateral to the corpus luteum. All animals were slaughtered on d 14 to recover conceptuses, uterine fluid, and endometrial tissue. Glucose infusion increased circulating glucose concentrations (4.70 ± 0.12 vs. 4.15 ± 0.12 mmol/L) but did not affect milk production or dry matter intake. Circulating β-hydroxybutyrate concentrations were decreased (0.51 ± 0.01 vs. 0.70 ± 0.01 mmol/L for GLUC vs. CTRL, respectively) but plasma fatty acids, progesterone, and insulin concentrations were unaffected by treatment. Treatment did not affect either uterine lumen fluid glucose concentration or the mRNA abundance of specific glucose transporters in the endometrium. Mean conceptus length, width, and area on d 14 were reduced in the GLUC treatment compared with the CTRL treatment. A greater proportion of embryos in the CTRL group had elongated to all length cut-off measurements between 11 and 20 mm (measured in 1-mm increments) compared with the GLUC treatment. In conclusion, infusion of glucose into lactating dairy cows from d 7 to d 14 post-estrus during the critical period of conceptus elongation had an adverse impact on early embryonic development

    Implied volatility of basket options at extreme strikes

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    In the paper, we characterize the asymptotic behavior of the implied volatility of a basket call option at large and small strikes in a variety of settings with increasing generality. First, we obtain an asymptotic formula with an error bound for the left wing of the implied volatility, under the assumption that the dynamics of asset prices are described by the multidimensional Black-Scholes model. Next, we find the leading term of asymptotics of the implied volatility in the case where the asset prices follow the multidimensional Black-Scholes model with time change by an independent increasing stochastic process. Finally, we deal with a general situation in which the dependence between the assets is described by a given copula function. In this setting, we obtain a model-free tail-wing formula that links the implied volatility to a special characteristic of the copula called the weak lower tail dependence function

    Discovery of shocked H2 around OH 231.8+4.2

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    We present K-band integral field observations of the circumstellar envelope of the evolved star OH 231.8+4.2. Spatial and spectral information were simultaneously acquired using the Sinfoni integral field unit, with adaptive optics, on the Very Large Telescope. The observations reveal the discovery of H2 emission (1) around the centre of the nebula and (2) located in clumps along the Western side of the Northern lobe, presumably associated with the strong shocks that stimulate the previously reported H-alpha emission at the same location. An observed H2 1-0/2-1S(1) line ratio of 8.3+/-1.9 was calculated for the central field, a value consistent with shock excitation.Comment: 5 pages, 4 figures, accepted for publication in MNRAS Letter

    A feasibility randomised controlled trial of the New Orleans intervention of infant mental health: a study protocol

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    Child maltreatment is associated with life-long social, physical, and mental health problems. Intervening early to provide maltreated children with safe, nurturing care can improve outcomes. The need for prompt decisions about permanent placement (i.e., regarding adoption or return home) is internationally recognised. However, a recent Glasgow audit showed that many maltreated children “revolve” between birth families and foster carers. This paper describes the protocol of the first exploratory randomised controlled trial of a mental health intervention aimed at improving placement permanency decisions for maltreated children. This trial compares an infant's mental health intervention with the new enhanced service as usual for maltreated children entering care in Glasgow. As both are new services, the trial is being conducted from a position of equipoise. The outcome assessment covers various fields of a child’s neurodevelopment to identify problems in any ESSENCE domain. The feasibility, reliability, and developmental appropriateness of all outcome measures are examined. Additionally, the potential for linkage with routinely collected data on health and social care and, in the future, education is explored. The results will inform a definitive randomised controlled trial that could potentially lead to long lasting benefits for the Scottish population and which may be applicable to other areas of the world
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