3,030 research outputs found

    An XMM-Newton view of M101 - III. Diffuse X-ray emission

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    We present a study of the X-ray properties of the nearby face-on Scd spiral galaxy M101 based on recent XMM–Newton observations. In this third and final paper in the present series, we focus on the spatial and spectral properties of the residual emission, after excluding bright X-ray sources with LX > 1037 erg s−1. Within a central region of radius 10 arcmin (21 kpc), the X-ray emission broadly traces the pattern of the spiral arms, establishing a strong link with recent star formation, but it also exhibits a radial scalelength of ≈2.6 arcmin (5.4 kpc) consistent with optical data. We estimate the soft X-ray luminosity within the central 5 arcmin (10.5 kpc) region to be LX ≈ 2.1 × 1039 erg s−1 (0.5–2 keV), the bulk of which appears to originate as diffuse emission. We find a two-temperature thermal model best fits the spectral data with derived temperatures of keV which are very typical of the diffuse components seen in other normal and starburst galaxies. More detailed investigation of the X-ray morphology reveals a strong correlation with images recorded in the far-ultraviolet through to V band, with the best match being with the U band. We interpret these results in terms of a clumpy thin-disc component which traces the spiral arms of M101 plus an extended lower halo component with large filling factor

    A conservation assessment of Rousettus madagascariensis (G. Grandidier, 1928, Pteropodidae) roosts in eastern Madagascar

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    We visited four cave roosts of the near threatened, and endemic, fruit bat Rousettus madagascariensis over a five year period and found major threats to the bats from hunting and deforestation. The conservation of this species is particularly challenging because it is legally hunted inside its cave roosts. Although provisional protected area status was obtained for two sites with community support, hunting continued. R. madagascariensis roosts were associated with humid forest and the loss of vegetation around caves rendered them unsuitable for the bats at two abandoned sites. A few individual hunters can have a rapid and destructive impact on R. madagascariensis roosts and future initiatives in this area should involve working with hunters to develop realistic solutions to reduce hunting. These efforts need to be supported by habitat protection measures.RÉSUMÉL’espèce de chauve - souris frugivore Quasi Menacée Rousettus madagascariensis est endémique à Madagascar. Nous avons étudié quatre gîtes dans des grottes où cette espèce a établi des dortoirs diurnes en procédant à des visites multiples au cours d’une période de cinq ans et avons trouvé que la chasse et la déforestation constituaient les principales menaces pesant sur R. madagascariensis. La conservation de cette espèce est particulièrement difficile dans la mesure où la chasse dans ses dortoirs ou gîtes est permise. Bien que les deux sites abritant l’espèce bénéficient du statut de Nouvelle Aire Protégée avec le soutien de la communauté locale, la chasse ne cesse de s’intensifier. Les gîtes de R. madagascariensis sont associés à la forêt humide, de sorte que la disparition de la végétation arborée autour de deux de ces gîtes les a rendus impropres à héberger R. madagascariensis qui a fini par les abandonner. La disparition de la végétation arborée autour du gîte pourrait être à l’origine d’un changement de microclimat à l’intérieur de la grotte qui constitue le gîte diurne. Les activités de certains chasseurs peuvent aussi avoir un impact destructif rapide sur les gîtes de R. madagascariensis et des initiatives à mener conjointement avec les chasseurs sont nécessaires pour élaborer des mesures réalistes afin de réduire la chasse. De tels efforts doivent être étendus et appuyés par des mesures de protection de l’habitat car plusieurs autres gîtes pourraient exister dans les forêts du versant est de Madagascar et subir les mêmes pressions anthropiques. Des recherches récentes ont également montré que l’histoire naturelle de R. madagascariensis est étroitement liée à la forêt naturelle, de sorte que la perte de la biodiversité de la forêt naturelle malgache menace les plantes dont se nourrit cette espèce ainsi que l’équilibre de l’ensemble de l’écosystème dont elle dépend

    Detecting and monitoring incontinence associated dermatitis: Does impedance spectroscopy have a part to play?

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    This is the final version. Available from SAGE Publications via the DOI in this record. In this review, current understanding of the prevention and treatment of Incontinence Associated Dermatitis (IAD) is discussed. The need for preventative measures which target specific faecal/urinary irritants is highlighted, including the role of urease inhibitors. There is no existing internationally and clinically accepted method to diagnose and categorise the severity of IAD. Diagnosis currently relies on visual inspection; non-invasive techniques to assess skin barrier function could remove subjectiveness, particularly in darker skin tones. Impedance spectroscopy is a non-invasive technique which can be used to monitor skin barrier function, supporting visual assessments. Six studies (2003-2021) which used impedance to assess dermatitis were reviewed; inflamed skin was distinguishable from healthy skin in each case. This suggests that impedance spectroscopy could be useful in diagnosis early-stage IAD, potentially enabling earlier intervention. Finally, the authors present their initial findings on the role of urease in skin breakdown in an in vivo IAD model, using impedance spectroscopy.University of BathConvaTec Ltd.Annette TrustEngineering and Physical Sciences Research Council (EPSRC

    The masses and density profiles of halos in a LCDM galaxy formation simulation

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    We investigate the internal structure and density profiles of halos of mass 1010−1014 M⊙10^{10}-10^{14}~M_\odot in the Evolution and Assembly of Galaxies and their Environment (EAGLE) simulations. These follow the formation of galaxies in a Λ\LambdaCDM Universe and include a treatment of the baryon physics thought to be relevant. The EAGLE simulations reproduce the observed present-day galaxy stellar mass function, as well as many other properties of the galaxy population as a function of time. We find significant differences between the masses of halos in the EAGLE simulations and in simulations that follow only the dark matter component. Nevertheless, halos are well described by the Navarro-Frenk-White (NFW) density profile at radii larger than ~5% of the virial radius but, closer to the centre, the presence of stars can produce cuspier profiles. Central enhancements in the total mass profile are most important in halos of mass 1012−1013M⊙10^{12}-10^{13}M_\odot, where the stellar fraction peaks. Over the radial range where they are well resolved, the resulting galaxy rotation curves are in very good agreement with observational data for galaxies with stellar mass M∗<5×1010M⊙M_*<5\times10^{10}M_\odot. We present an empirical fitting function that describes the total mass profiles and show that its parameters are strongly correlated with halo mass

    The chosen few: the low mass halos that host faint galaxies

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    Since reionization prevents star formation in most halos below 3 x 10^9 solar masses, dwarf galaxies only populate a fraction of existing dark matter halos. We use hydrodynamic cosmological simulations of the Local Group to study the discriminating factors for galaxy formation in the early Universe and connect them to the present-day properties of galaxies and halos. A combination of selection effects related to reionization, and the subsequent evolution of halos in different environments, introduces strong biases between the population of halos that host dwarf galaxies, and the total halo population. Halos that host galaxies formed earlier and are more concentrated. In addition, halos more affected by tidal stripping are more likely to host a galaxy for a given mass or maximum circular velocity, vmax, today. Consequently, satellite halos are populated more frequently than field halos, and satellite halos of 10^8 - 10^9 solar masses or vmax of 12 - 20 km/s, similar to the Local Group dwarf spheroidals, have experienced a greater than average reduction in both mass and vmax after infall. They are on closer, more radial orbits with higher infall velocities and earlier infall times. Together, these effects make dwarf galaxies highly biased tracers of the underlying dark matter distribution

    Patient-reported Quality of Life outcomes in patients treated for muscle-invasive bladder cancer with radiotherapy ± chemotherapy in the BC2001 Phase III Randomised Controlled Trial

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    BC2001, the largest randomised trial of bladder-sparing treatment for muscle-invasive bladder cancer, demonstrated improvement of local control and bladder cancer-specific survival from the addition of concomitant 5-fluorouracil and mitomycin C to radiotherapy.This article is available via Open Access. Click on the Publisher URL to access the full-text

    Do rats learn conditional independence?

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    If acquired associations are to accurately represent real relevance relations, there is motivation for the hypothesis that learning will, in some circumstances, be more appropriately modelled, not as direct dependence, but as conditional independence. In a serial compound conditioning experiment, two groups of rats were presented with a conditioned stimulus (CS1) that imperfectly (50%) predicted food, and was itself imperfectly predicted by a CS2. Groups differed in the proportion of CS2 presentations that were ultimately followed by food (25% versus 75%). Thus, the information presented regarding the relevance of CS2 to food was ambiguous between direct dependence and conditional independence (given CS1). If rats learnt that food was conditionally independent of CS2, given CS1, subjects of both groups should thereafter respond similarly to CS2 alone. Contrary to the conditionality hypothesis, subjects attended to the direct food predictability of CS2, suggesting that rats treat even distal stimuli in a CS sequence as immediately relevant to food, not conditional on an intermediate stimulus. These results urge caution in representing indirect associations as conditional associations, accentuate the theoretical weight of the Markov condition in graphical models, and challenge theories to articulate the conditions under which animals are expected to learn conditional associations, if ever.All funding for the project was internal, from Indiana University

    Respiratory muscle strength as a predictive biomarker for survival in amyotrophic lateral sclerosis

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    Rationale: Biomarkers for survival in amyotrophic lateral sclerosis (ALS) would facilitate the development of novel drugs. Although respiratory muscle weakness is a known predictor of poor prognosis, a comprehensive comparison of different tests is lacking. Objectives: To compare the predictive power of invasive and noninvasive respiratory muscle strength assessments for survival or ventilator-free survival, up to 3 years. Methods: From a previously published report respiratory muscle strength measurements were available for 78 patients with ALS. Time to death and/or ventilation were ascertained. Receiver operating characteristic analysis was used to determine the cutoff point of each parameter. Measurements and Main Results: Each respiratory muscle strength assessment individually achieved statistical significance for prediction of survival or ventilator-free survival. In multivariate analysis sniff trans-diaphragmatic and esophageal pressure, twitch trans-diaphragmatic pressure (Tw Pdi), age, and maximal static expiratory mouth pressure were significant predictors of ventilation-free survival and Tw Pdi and maximal static expiratory mouth pressure for absolute survival. Although all measures had good specificity, there were differing sensitivities. All cutoff points for the VC were greater than 80% of normal, except for prediction of 3-month outcomes. Sequential data showed a linear decline for direct measures of respiratory muscle strength, whereas VC showed little to no decline until 12 months before death/ventilation. Conclusions: The most powerful biomarker for mortality stratification was Tw Pdi, but the predictive power of sniff nasal inspiratory pressure was also excellent. A VC within normal range suggested a good prognosis at 3 months but was of little other value
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