155 research outputs found
The Red Supergiant Content of M31
We investigate the red supergiant (RSG) population of M31, obtaining radial
velocities of 255 stars. These data substantiate membership of our
photometrically-selected sample, demonstrating that Galactic foreground stars
and extragalactic RSGs can be distinguished on the basis of B-V, V-R two-color
diagrams. In addition, we use these spectra to measure effective temperatures
and assign spectral types, deriving physical properties for 192 RSGs.
Comparison with the solar-metallicity Geneva evolutionary tracks indicates
astonishingly good agreement. The most luminous RSGs in M31 are likely evolved
from 25-30 Mo stars, while the vast majority evolved from stars with initial
masses of 20 Mo or less. There is an interesting bifurcation in the
distribution of RSGs with effective temperatures that increases with higher
luminosities, with one sequence consisting of early K-type supergiants, and
with the other consisting of M-type supergiants that become later (cooler) with
increasing luminosities. This separation is only partially reflected in the
evolutionary tracks, although that might be due to the mis-match in
metallicities between the solar Geneva models and the higher-than-solar
metallicity of M31. As the luminosities increase the median spectral type also
increases; i.e., the higher mass RSGs spend more time at cooler temperatures
than do those of lower luminosities, a result which is new to this study.
Finally we discuss what would be needed observationally to successfully build a
luminosity function that could be used to constrain the mass-loss rates of RSGs
as our Geneva colleagues have suggested.Comment: Accepted for publication in the Astronomical Journa
Applied Theatre in Adolescent Mental Health Transition Care
The Transition from CAMHS to AMHS
The transition from Child and Adolescent Mental Health Services (CAMHS) to Adult Mental Health Services (AMHS) has been recognised as a key concern within healthcare, described as a ‘cliff edge’ by the House of Commons Health Committee, and ‘poorly planned, poorly executed and poorly experienced’ by the National Institute for Health Research.1,2 This short article identifies one way of working in this area, together with plans to conduct research evaluating the initiative.
CAMHS and AMHS are very different services, with distinct histories, philosophies and approaches; adult psychiatry evolved out of the asylum, whereas child psychiatry emerged later and concerned itself more with developmental issues, education and family relationships. For a young person negotiating this interface (usually on turning 18, although sometimes younger, as services across the country do operate differently), it therefore does not simply involve adjusting to a new physical environment and new professionals, but also adapting to a service that considers them as autonomous adults, rather than as part of the family unit. As well as the level and style of intervention, differences in eligibility thresholds for referral also means that the remit for AMHS is narrower and they may get no input from services at all.
When discussing (or referring to) transition, it is useful to distinguish this from transfer, where the latter is simply the termination of input from child services and the commencement of input from adult services. Transition should be a therapeutic experience and involve preparation: ‘a period of handover or joint care, transition planning meetings (involving the young person and carer, and key CAMHS and AMHS professionals) and transfer of case notes or information summaries’.3 Young people experiencing this quality of transition is, sadly, rare, and thus – while also recognising the need for systemic change, locally and nationally – support for young people negotiating the challenges of moving between services needs to be developed
A Runaway Red Supergiant in M31
A significant percentage of OB stars are runaways, so we can expect a similar percentage of their evolved descendants to also be runaways. However, recognizing such stars presents its own set of challenges, as these older, more evolved stars will have drifted farther from their birthplace, and thus their velocities might not be obviously peculiar. Several Galactic red supergiants (RSGs) have been described as likely runaways based on the existence of bow shocks, including Betelgeuse. Here we announce the discovery of a runaway RSG in M31 based on a 300 km s^(−1) discrepancy with M31's kinematics. The star is found about 21' (4.6 kpc) from the plane of the disk, but this separation is consistent with its velocity and likely age (~10 Myr). The star, J004330.06+405258.4, is an M2 I, with M_V = −5.7, logL/L_☉ = 4.76, an effective temperature of 3700 K, and an inferred mass of 12–15M_⊙. The star may be a high-mass analog of the hypervelocity stars, given that its peculiar space velocity is probably 400–450 km s^(−1), comparable to the escape speed from M31's disk
Differential reproductive plasticity under thermal variability in a freshwater fish (Danio rerio)
publishedVersionPaid Open Acces
Differential reproductive plasticity under thermal variability in a freshwater fish (Danio rerio)
Human-driven increases in global mean temperatures are associated with concomitant increases in thermal variability. Yet, few studies have explored the impacts of thermal variability on fitness-related traits, limiting our ability to predict how organisms will respond to dynamic thermal changes. Among the myriad organismal responses to thermal variability, one of the most proximate to fitness—and, thus, a population's ability to persist—is reproduction. Here, we examine how a model freshwater fish (Danio rerio) responds to diel thermal fluctuations that span the species's viable developmental range of temperatures. We specifically investigate reproductive performance metrics including spawning success, fecundity, egg provisioning and sperm concentration. Notably, we apply thermal variability treatments during two ontogenetic timepoints to disentangle the relative effects of developmental plasticity and reversible acclimation. We found evidence of direct, negative effects of thermal variability during later ontogenetic stages on reproductive performance metrics. We also found complex interactive effects of early and late-life exposure to thermal variability, with evidence of beneficial acclimation of spawning success and modification of the relationship between fecundity and egg provisioning. Our findings illuminate the plastic life-history modifications that fish may undergo as their thermal environments become increasingly variable.publishedVersio
The White Dwarf Population in NGC 1039 (M34) and the White Dwarf Initial-Final Mass Relation
We present the first detailed photometric and spectroscopic study of the
white dwarfs (WDs) in the field of the ~225 Myr old (log tau_cl = 8.35) open
cluster NGC 1039 (M34) as part of the ongoing Lick-Arizona White Dwarf Survey.
Using wide-field UBV imaging, we photometrically select 44 WD candidates in
this field. We spectroscopically identify 19 of these objects as WDs; 17 are
hydrogen-atmosphere DA WDs, one is a helium-atmosphere DB WD, and one is a cool
DC WD that exhibits no detectable absorption lines. We find an effective
temperature (T_eff) and surface gravity (log g) for each DA WD by fitting
Balmer-line profiles from model atmospheres to the observed spectra. WD
evolutionary models are then invoked to derive masses and cooling times for
each DA WD. Of the 17 DAs, five are at the approximate distance modulus of the
cluster. Another WD with a distance modulus 0.45 mag brighter than that of the
cluster could be a double-degenerate binary cluster member, but is more likely
to be a field WD. We place the five single cluster member WDs in the empirical
initial-final mass relation and find that three of them lie very close to the
previously derived linear relation; two have WD masses significantly below the
relation. These outliers may have experienced some sort of enhanced mass loss
or binary evolution; however, it is quite possible that these WDs are simply
interlopers from the field WD population. Eight of the 17 DA WDs show
significant CaII K absorption; comparison of the absorption strength with the
WD distances suggests that the absorption is interstellar, though this cannot
be confirmed with the current data.Comment: 24 pages, 13 figures. Accepted for publication in the Astronomical
Journal. Figures 1, 2 and 3 reduced in resolutio
Identifying Causal Genes at the Multiple Sclerosis Associated Region 6q23 Using Capture Hi-C.
BACKGROUND: The chromosomal region 6q23 has been found to be associated with multiple sclerosis (MS) predisposition through genome wide association studies (GWAS). There are four independent single nucleotide polymorphisms (SNPs) associated with MS in this region, which spans around 2.5 Mb. Most GWAS variants associated with complex traits, including these four MS associated SNPs, are non-coding and their function is currently unknown. However, GWAS variants have been found to be enriched in enhancers and there is evidence that they may be involved in transcriptional regulation of their distant target genes through long range chromatin looping. AIM: The aim of this work is to identify causal disease genes in the 6q23 locus by studying long range chromatin interactions, using the recently developed Capture Hi-C method in human T and B-cell lines. Interactions involving four independent associations unique to MS, tagged by rs11154801, rs17066096, rs7769192 and rs67297943 were analysed using Capture Hi-C Analysis of Genomic Organisation (CHiCAGO). RESULTS: We found that the pattern of chromatin looping interactions in the MS 6q23 associated region is complex. Interactions cluster in two regions, the first involving the rs11154801 region and a second containing the rs17066096, rs7769192 and rs67297943 SNPs. Firstly, SNPs located within the AHI1 gene, tagged by rs11154801, are correlated with expression of AHI1 and interact with its promoter. These SNPs also interact with other potential candidate genes such as SGK1 and BCLAF1. Secondly, the rs17066096, rs7769192 and rs67297943 SNPs interact with each other and with immune-related genes such as IL20RA, IL22RA2, IFNGR1 and TNFAIP3. Finally, the above-mentioned regions interact with each other and therefore, may co-regulate these target genes. CONCLUSION: These results suggest that the four 6q23 variants, independently associated with MS, are involved in the regulation of several genes, including immune genes. These findings could help understand mechanisms of disease and suggest potential novel therapeutic targets
'Staying strong on the inside and outside' to keep walking and moving around: perspectives from Aboriginal people with Machado Joseph Disease and their families from the Groote Eylandt Archipelago, Australia
Machado Joseph Disease (MJD) (spinocerebellar ataxia 3) is a hereditary neurodegenerative disease causing progressive ataxia and loss of mobility. It is the most common spinocerebellar ataxia worldwide. Among Aboriginal families of Groote Eylandt and related communities across Australia's Top End, MJD is estimated to be more prevalent than anywhere else in the world. This study explored lived experiences of individuals and families with MJD to determine what is important and what works best to keep walking and moving around. A collaborative qualitative exploratory study, drawing from constructivist grounded theory methods, was undertaken for data collection and analysis. Semi-structured in-depth interviews were conducted with individuals with MJD (n = 8) and their family members (n = 4) from the Groote Eylandt Archipelago where similar to 1500 Aboriginal people (Warnumamalya) live. Interviews were led by Warnumamalya community research partners in participants' preferred language(s). Participants described their experience of living with MJD, from 'knowing about MJD', 'protecting yourself from MJD' and 'adjusting to life with MJD'. While the specific importance of walking and moving around differed widely between participants, all perceived that walking and moving around enabled them to do what mattered most to them in life. 'Staying strong on the inside and outside' (physically, mentally, emotionally, spiritually) was perceived to work best to keep walking and moving around as long as possible. A framework that included personal and environmental strategies for staying strong emerged: 'Exercising your body', 'having something important to do', 'keeping yourself happy', 'searching for good medicine', 'families helping each other' and 'going country'. This study, the first to explore lived experiences of MJD in Australia, highlights the importance of maintaining mobility as long as possible. Strategies perceived to work best address physical and psychosocial needs in an integrated manner. Services supporting families with MJD need flexibility to provide individualised, responsive and holistic care
How to do it: the neurological consultation with an autistic patient
Autism is a neurodevelopmental condition with a very heterogeneous presentation. Autistic people are more likely to have unmet healthcare needs, making it essential that healthcare professionals are ‘autism-aware’. In this article, we provide an overview of how autism presents and use case studies to illustrate how a neurological consultation in an outpatient clinic environment could prove challenging for a autistic person. We suggest how to improve communication with autistic patients in clinic and highlight the importance of a patient-centred and flexible approach
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