2,676 research outputs found

    OH maser mapping of the evolved star HD 179821: evidence for interacting outllows

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    The evolved star HD 179821 continues to be the subject of much debate as to whether it is a nearby post-asymptotic giant branch (post-AGB) star or a distant high initial mass post-red supergiant. We have mapped the OH maser emission around HD 179821 in the 1612- and 1667-MHz lines with the MERLIN interferometer array at a resolution of 0.4 arcsec and 0.35 km s−1. The OH emission lies in a thick shell with inner and outer radii of 1.3 and and expansion velocity of 30 km s−1. Although we find some evidence for acceleration and for deviations from spherical symmetry, the bulk of the maser emission is consistent with a constant-velocity spherical shell. The extent of the shell agrees with H2O and OH dissociation models and supports a distance estimate of 6 kpc. However, the shell is incomplete and appears to have been disrupted by more recent collimated outflow activity within the last 1500 yr. We suggest that this activity is also responsible for the active envelope chemistry (in particular the presence of HCO+) and for the apparent offset of the star from the centre of the shell. The luminous yellow hypergiant star IRC +10420 also shows signs of recent outflows, and HD 179821 may be at a similar, perhaps slightly earlier, phase of evolution. We suggest that the SiO thermal emission arises from the same detached envelope as the OH maser emission as in IRC +10420. If so then this would strengthen the connection between these two stars and probably rule out a post-AGB status for HD 179821

    Turning to art as a positive way of living with cancer: A qualitative study of personal motives and contextual influences

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    Why do some women turn to creative art-making after a diagnosis of cancer? Eleven women provided qualitative accounts that were analyzed following guidelines for interpretative phenomenological analysis (IPA). Some described taking up artistic leisure activities initially in order to manage emotional distress. Others emphasized their need for positive well-being, taking up art to experience achievement and satisfaction, to regain a positive identity, and to normalize family dynamics in the context of living with cancer. Participants’ turn to art-making was facilitated by biographical and contextual factors, including pre-existing craft skills, long-standing personal values and coping philosophies, family role models for managing adversity, and the supportive encouragement of family and friends. Other research has acknowledged that positive lifestyle change and post-traumatic growth can occur after a cancer diagnosis, and this study reveals a multi-faceted process. The findings suggest a need for further research into the experiences that facilitate positive lifestyle change and subjective well-being among people who are living with cancer

    Promoting the consumer voice : the role of Healthwatch Salford's Enter and View programme

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    The daily business of running a care home means that, outside of regulatory inspections, assessing and improving the user experience can often be forgotten. Healthwatch Salford discuss their process of gaining constructive feedback using their innovative Enter and View programm

    e-MERLIN 21 cm constraints on the mass-loss rates of OB stars in Cyg OB2

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    We present e-MERLIN 21 cm (L-band) observations of single luminous OB stars in the Cygnus OB2 association, from the Cyg OB2 Radio Survey Legacy programme. The radio observations potentially offer the most straightforward, least model-dependent, determinations of mass-loss rates, and can be used to help resolve current discrepancies in mass-loss rates via clumped and structured hot star winds. We report here that the 21 cm flux densities of O3 to O6 supergiant and giant stars are less than ∼70 μJy. These fluxes may be translated to ‘smooth’ wind mass-loss upper limits of ∼4.4–4.8 × 10−6 M⊙ yr −1 for O3 supergiants and ≲2.9 × 10−6 M⊙ yr −1 for B0 to B1 supergiants. The first ever resolved 21 cm detections of the hypergiant (and luminous blue variable candidate) Cyg OB2 #12 are discussed; for multiple observations separated by 14 d, we detect an ∼69 per cent increase in its flux density. Our constraints on the upper limits for the mass-loss rates of evolved OB stars in Cyg OB2 support the model that the inner wind region close to the stellar surface (where Hα forms) is more clumped than the very extended geometric region sampled by our radio observations

    Co-propagation of maser emission at 1720 and 4765 MHz

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    MERLIN observations are presented of OH 4765-MHz and OH 1720-MHz masers in the massive star-forming region W3(OH). Two of the three intense spots of maser emission at 4765 MHz are spatially coincident with two similar spots at 1720 MHz in both left-hand circular (LHC) and right-hand circular (RHC) polarizations, to an accuracy of 15 mas. The spots also overlap in velocity when allowance is made for Zeeman splitting of the 1720-MHz line. We conclude that we have found two examples of masers in different rotational levels of OH which are co-propagating through the same column of gas and experiencing competitive gain effects. The third 4765-MHz maser spot was found to have no overlapping counterpart amongst the 1720-MHz masers

    Profiling strugglers in a graduate-entry medicine course at Nottingham: a retrospective case study

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    Background 10-15% of students struggle at some point in their medicine course. Risk factors include weaker academic qualifications, male gender, mental illness, UK ethnic minority status, and poor study skills. Recent research on an undergraduate medicine course provided a toolkit to aid early identification of students likely to struggle, who can be targeted by established support and study interventions. The present study sought to extend this work by investigating the number and characteristics of strugglers on a graduate-entry medicine (GEM) programme. Methods A retrospective study of four GEM entry cohorts (2003–6) was carried out. All students who had demonstrated unsatisfactory progress or left prematurely were included. Any information about academic, administrative, personal, or social difficulties, were extracted from their course progress files into a customised database and examined. Results 362 students were admitted to the course, and 53 (14.6%) were identified for the study, of whom 15 (4.1%) did not complete the course. Students in the study group differed from the others in having a higher proportion of 2ii first degrees, and scoring less well on GAMSAT, an aptitude test used for admission. Within the study group, it proved possible to categorise students into the same groups previously reported (struggler throughout, pre-clinical struggler, clinical struggler, health-related struggler, borderline struggler) and to identify the majority using a number of flags for early difficulties. These flags included: missed attendance, unsatisfactory attitude or behaviour, health problems, social/family problems, failure to complete immunity status checks, and attendance at academic progress committee. Conclusions Problems encountered in a graduate-entry medicine course were comparable to those reported in a corresponding undergraduate programme. A toolkit of academic and non-academic flags of difficulty can be used for early identification of many who will struggle, and could be used to target appropriate support and interventions

    A structural and dynamic model for the assembly of Replication Protein A on single-stranded DNA

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    Replication Protein A (RPA), the major eukaryotic single stranded DNA-binding protein, binds to exposed ssDNA to protect it from nucleases, participates in a myriad of nucleic acid transactions and coordinates the recruitment of other important players. RPA is a heterotrimer and coats long stretches of single-stranded DNA (ssDNA). The precise molecular architecture of the RPA subunits and its DNA binding domains (DBDs) during assembly is poorly understood. Using cryo electron microscopy we obtained a 3D reconstruction of the RPA trimerisation core bound with ssDNA (∼55 kDa) at ∼4.7 Å resolution and a dimeric RPA assembly on ssDNA. FRET-based solution studies reveal dynamic rearrangements of DBDs during coordinated RPA binding and this activity is regulated by phosphorylation at S178 in RPA70. We present a structural model on how dynamic DBDs promote the cooperative assembly of multiple RPAs on long ssDNA

    A Further Unique Chondroitin Sulfate from the shrimp Litopenaeus vannamei with Antithrombin Activity that Modulates Acute Inflammation

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    The detailed structure of a further Chondroitin Sulfate from Litopenaeus vannamei shrimp (sCS) is described. The backbone structure was established by 1H/13C NMR, which identified 3-O-sulfated GlcA, 4-O-sulfated GalNAc, 6-O-sulfated GalNAc, and 4,6-di-O-sulfated GalNAc residues. GlcA is linked to GalNAc 4,6 di S and GlcA 3S is linked to GalNAc 4S, GalNAc 4,6 di-S and GalNAc6S residues. The anticoagulant properties of this sCS were evaluated by activated partial thromboplastin time, anti-IIa, anti-Xa and anti-heparin cofactor II-mediated activities, and sCS failed to stabilise antithrombin in a fluoresence shift assay. The anti-inflammatory effect of sCS was explored using a model of acute peritonitis, followed by leukocyte count and measurement of the cytokines, IL-1β, IL-6 and TNF-ι. The compound showed low clotting effects, but high anti-IIa activity and HCII-mediated thrombin inhibition. Its anti-inflammatory effect was shown by leukocyte recruitment inhibition and a decrease in pro-inflammatory cytokine levels. Although the biological role of sCS remains unknown, its properties indicate that it is suitable for studies of multi-potent molecules obtained from natural sources
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