768 research outputs found

    The SAMI Galaxy Survey: mass-kinematics scaling relations

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    We use data from the Sydney-AAO Multi-object Integral-field spectroscopy (SAMI) Galaxy Survey to study the dynamical scaling relation between galaxy stellar mass MM_* and the general kinematic parameter SK=KVrot2+σ2S_K = \sqrt{K V_{rot}^2 + \sigma^2} that combines rotation velocity VrotV_{rot} and velocity dispersion σ\sigma. We show that the logMlogSK\log M_* - \log S_K relation: (1)~is linear above limits set by properties of the samples and observations; (2)~has slightly different slope when derived from stellar or gas kinematic measurements; (3)~applies to both early-type and late-type galaxies and has smaller scatter than either the Tully-Fisher relation (logMlogVrot\log M_* - \log V_{rot}) for late types or the Faber-Jackson relation (logMlogσ\log M_* - \log\sigma) for early types; and (4)~has scatter that is only weakly sensitive to the value of KK, with minimum scatter for KK in the range 0.4 and 0.7. We compare SKS_K to the aperture second moment (the `aperture velocity dispersion') measured from the integrated spectrum within a 3-arcsecond radius aperture (σ3\sigma_{3^{\prime\prime}}). We find that while SKS_{K} and σ3\sigma_{3^{\prime\prime}} are in general tightly correlated, the logMlogSK\log M_* - \log S_K relation has less scatter than the logMlogσ3\log M_* - \log \sigma_{3^{\prime\prime}} relation.Comment: 14 pages, 8 figures, Accepted 2019 May 22. Received 2019 May 18; in original form 2019 January

    Surgical ward rounds in England: a trainee-led multi-centre study of current practice

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    BACKGROUND: Recent guidance advocates daily consultant-led ward rounds, conducted in the morning with the presence of senior nursing staff and minimising patients on outlying wards. These recommendations aim to improve patient management through timely investigations, treatment and discharge. This study sought to evaluate the current surgical ward round practices in England. METHODS: Information regarding timing and staffing levels of surgical ward rounds was collected prospectively over a one-week period. The location of each patient was also documented. Two surgical trainee research collaboratives coordinated data collection from 19 hospitals and 13 surgical subspecialties. RESULTS: Data from 471 ward rounds involving 5622 patient encounters was obtained. 367 (77.9%) ward rounds commenced before 9am. Of 422 weekday rounds, 190 (45%) were consultant-led compared with 33 of the 49 (67%) weekend rounds. 2474 (44%) patients were seen with a nurse present. 1518 patients (27%) were classified as outliers, with 361 ward rounds (67%) reporting at least one outlying patient. CONCLUSION: Recommendations for daily consultant-led multi disciplinary ward rounds are poorly implemented in surgical practice, and patients continue to be managed on outlying wards. Although strategies may be employed to improve nursing attendance on ward rounds, substantial changes to workforce planning would be required to deliver daily consultant-led care. An increasing political focus on patient outcomes at weekends may prompt changes in these areas

    The SAMI Galaxy Survey: Revising the Fraction of Slow Rotators in IFS Galaxy Surveys

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    The fraction of galaxies supported by internal rotation compared to galaxies stabilized by internal pressure provides a strong constraint on galaxy formation models. In integral field spectroscopy surveys, this fraction is biased because survey instruments typically only trace the inner parts of the most massive galaxies. We present aperture corrections for the two most widely used stellar kinematic quantities V/σV/\sigma and λR\lambda_{R}. Our demonstration involves integral field data from the SAMI Galaxy Survey and the ATLAS3D^{\rm{3D}} Survey. We find a tight relation for both V/σV/\sigma and λR\lambda_{R} when measured in different apertures that can be used as a linear transformation as a function of radius, i.e., a first-order aperture correction. We find that V/σV/\sigma and λR\lambda_{R} radial growth curves are well approximated by second order polynomials. By only fitting the inner profile (0.5ReR_{\rm{e}}), we successfully recover the profile out to one ReR_{\rm{e}} if a constraint between the linear and quadratic parameter in the fit is applied. However, the aperture corrections for V/σV/\sigma and λR\lambda_{R} derived by extrapolating the profiles perform as well as applying a first-order correction. With our aperture-corrected λR\lambda_{R} measurements, we find that the fraction of slow rotating galaxies increases with stellar mass. For galaxies with logM/M>\log M_{*}/M_{\odot}> 11, the fraction of slow rotators is 35.9±4.335.9\pm4.3 percent, but is underestimated if galaxies without coverage beyond one ReR_{\rm{e}} are not included in the sample (24.2±5.324.2\pm5.3 percent). With measurements out to the largest aperture radius the slow rotator fraction is similar as compared to using aperture corrected values (38.3±4.438.3\pm4.4 percent). Thus, aperture effects can significantly bias stellar kinematic IFS studies, but this bias can now be removed with the method outlined here.Comment: Accepted for Publication in the Monthly Notices of the Royal Astronomical Society. 16 pages and 11 figures. The key figures of the paper are: 1, 4, 9, and 1

    Mutations in KCNK4 that Affect Gating Cause a Recognizable Neurodevelopmental Syndrome

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    Aberrant activation or inhibition of potassium (K+) currents across the plasma membrane of cells has been causally linked to altered neurotransmission, cardiac arrhythmias, endocrine dysfunction, and (more rarely) perturbed developmental processes. The K+ channel subfamily K member 4 (KCNK4), also known as TRAAK (TWIK-related arachidonic acid-stimulated K+ channel), belongs to the mechano-gated ion channels of the TRAAK/TREK subfamily of two-pore-domain (K2P) K+ channels. While K2P channels are well known to contribute to the resting membrane potential and cellular excitability, their involvement in pathophysiological processes remains largely uncharacterized. We report that de novo missense mutations in KCNK4 cause a recognizable syndrome with a distinctive facial gestalt, for which we propose the acronym FHEIG (facial dysmorphism, hypertrichosis, epilepsy, intellectual disability/developmental delay, and gingival overgrowth). Patch-clamp analyses documented a significant gain of function of the identified KCNK4 channel mutants basally and impaired sensitivity to mechanical stimulation and arachidonic acid. Co-expression experiments indicated a dominant behavior of the disease-causing mutations. Molecular dynamics simulations consistently indicated that mutations favor sealing of the lateral intramembrane fenestration that has been proposed to negatively control K+ flow by allowing lipid access to the central cavity of the channel. Overall, our findings illustrate the pleiotropic effect of dysregulated KCNK4 function and provide support to the hypothesis of a gating mechanism based on the lateral fenestrations of K2P channels

    Phylogenomics and the dynamic genome evolution of the genus Streptococcus

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    The genus Streptococcus comprises important pathogens that have a severe impact on human health and are responsible for substantial economic losses to agriculture. Here, we utilize 46 Streptococcus genome sequences (44 species), including eight species sequenced here, to provide the first genomic level insight into the evolutionary history and genetic basis underlying the functional diversity of all major groups of this genus. Gene gain/loss analysis revealed a dynamic pattern of genome evolution characterized by an initial period of gene gain followed by a period of loss, as the major groups within the genus diversified. This was followed by a period of genome expansion associated with the origins of the present extant species. The pattern is concordant with an emerging view that genomes evolve through a dynamic process of expansion and streamlining. A large proportion of the pan-genome has experienced lateral gene transfer (LGT) with causative factors, such as relatedness and shared environment, operating over different evolutionary scales. Multiple gene ontology terms were significantly enriched for each group, and mapping terms onto the phylogeny showed that those corresponding to genes born on branches leading to the major groups represented approximately one-fifth of those enriched. Furthermore, despite the extensive LGT, several biochemical characteristics have been retained since group formation, suggesting genomic cohesiveness through time, and that these characteristics may be fundamental to each group. For example, proteolysis: mitis group; urea metabolism: salivarius group; carbohydrate metabolism: pyogenic group; and transcription regulation: bovis group

    Determining the date of diagnosis – is it a simple matter? The impact of different approaches to dating diagnosis on estimates of delayed care for ovarian cancer in UK primary care

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    Background Studies of cancer incidence and early management will increasingly draw on routine electronic patient records. However, data may be incomplete or inaccurate. We developed a generalisable strategy for investigating presenting symptoms and delays in diagnosis using ovarian cancer as an example. Methods The General Practice Research Database was used to investigate the time between first report of symptom and diagnosis of 344 women diagnosed with ovarian cancer between 01/06/2002 and 31/05/2008. Effects of possible inaccuracies in dating of diagnosis on the frequencies and timing of the most commonly reported symptoms were investigated using four increasingly inclusive definitions of first diagnosis/suspicion: 1. "Definite diagnosis" 2. "Ambiguous diagnosis" 3. "First treatment or complication suggesting pre-existing diagnosis", 4 "First relevant test or referral". Results The most commonly coded symptoms before a definite diagnosis of ovarian cancer, were abdominal pain (41%), urogenital problems(25%), abdominal distension (24%), constipation/change in bowel habits (23%) with 70% of cases reporting at least one of these. The median time between first reporting each of these symptoms and diagnosis was 13, 21, 9.5 and 8.5 weeks respectively. 19% had a code for definitions 2 or 3 prior to definite diagnosis and 73% a code for 4. However, the proportion with symptoms and the delays were similar for all four definitions except 4, where the median delay was 8, 8, 3, 10 and 0 weeks respectively. Conclusion Symptoms recorded in the General Practice Research Database are similar to those reported in the literature, although their frequency is lower than in studies based on self-report. Generalisable strategies for exploring the impact of recording practice on date of diagnosis in electronic patient records are recommended, and studies which date diagnoses in GP records need to present sensitivity analyses based on investigation, referral and diagnosis data. Free text information may be essential in obtaining accurate estimates of incidence, and for accurate dating of diagnoses

    Star-gas misalignment in galaxies: I. The properties of galaxies from the Horizon-AGN simulation and comparisons to SAMI

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    Recent integral field spectroscopy observations have found that about 11% of galaxies show star-gas misalignment. The misalignment possibly results from external effects such as gas accretion, interaction with other objects, and other environmental effects, hence providing clues to these effects. We explore the properties of misaligned galaxies using Horizon-AGN, a large-volume cosmological simulation, and compare the result with the result of the Sydney-AAO Multi-object integral field spectrograph (SAMI) Galaxy Survey. Horizon-AGN can match the overall misalignment fraction and reproduces the distribution of misalignment angles found by observations surprisingly closely. The misalignment fraction is found to be highly correlated with galaxy morphology both in observations and in the simulation: early-type galaxies are substantially more frequently misaligned than late-type galaxies. The gas fraction is another important factor associated with misalignment in the sense that misalignment increases with decreasing gas fraction. However, there is a significant discrepancy between the SAMI and Horizon-AGN data in the misalignment fraction for the galaxies in dense (cluster) environments. We discuss possible origins of misalignment and disagreement.Comment: 23 pages with 15 figures. Accepted for publication in Ap

    Repetitive Behavior in Rubinstein–Taybi Syndrome: Parallels with Autism Spectrum Phenomenology

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    Background. Syndrome specific repetitive behavior profiles have been described previously. A detailed profile is absent for Rubinstein-Taybi syndrome (RTS). Method. The Repetitive Behaviour Questionnaire and Social Communication Questionnaire (SCQ) were completed for children and adults RTS (N = 87), Fragile-X (N = 196) and Down (N = 132) syndromes, and individuals reaching cut-off for Autism Spectrum Disorder (ASD) (N = 228). Results. Total and matched group analyses were conducted. A phenotypic profile of repetitive behavior was found in RTS. The majority of behaviors in RTS were not associated with social-communication deficits or degree of disability. Conclusions. Repetitive behavior should be studied at a fine-grained level. A dissociation of the triad of impairments might be evident in RTS
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