The luminosity dependence of thermally-driven disc winds in low-mass X-ray binaries

We have carried out radiation-hydrodynamic simulations of thermally-driven accretion disc winds in low-mass X-ray binaries. Our main goal is to study the luminosity dependence of these outflows and compare with observations. The simulations span the range $\rm{0.04 \leq L_{acc}/L_{Edd} \leq 1.0}$ and therefore cover most of the parameter space in which disc winds have been observed. Using a detailed Monte Carlo treatment of ionization and radiative transfer, we confirm two key results found in earlier simulations that were carried out in the optically thin limit: (i) the wind velocity -- and hence the maximum blueshift seen in wind-formed absorption lines -- increases with luminosity; (ii) the large-scale wind geometry is quasi-spherical, but observable absorption features are preferentially produced along high-column equatorial sightlines. In addition, we find that (iii) the wind efficiency always remains approximately constant at $\rm{\dot{M}_{wind}/\dot{M}_{acc} \simeq 2}$, a behaviour that is consistent with observations. We also present synthetic Fe XXV and Fe XXVI absorption line profiles for our simulated disc winds in order to illustrate the observational implications of our results.Comment: Accepted for publication in MNRA

Comparison of T-cell Receptor Diversity of people with Myalgic Encephalomyelitis versus controls

Objective: Myalgic Encephalomyelitis (ME; sometimes referred to as Chronic Fatigue Syndrome) is a chronic disease without laboratory test, detailed aetiological understanding or effective therapy. Its symptoms are diverse, but it is distinguished from other fatiguing illnesses by the experience of post-exertional malaise, the worsening of symptoms even after minor physical or mental exertion. Its frequent onset after infection suggests autoimmune involvement or that it arises from abnormal T-cell activation. Results: To test this hypothesis, we sequenced the genomic loci of and T-cell receptors (TCR) from 40 human blood samples from each of four groups: severely affected people with ME; mildly or moderately affected people with ME; people diagnosed with Multiple Sclerosis, as disease controls; and, healthy controls. Seeking to automatically classify these individuals’ samples by their TCR repertoires, we applied P-SVM, a machine learning method. However, despite working well on a simulated data set, this approach did not allow statistically significant partitioning of samples into the four subgroups. Our findings do not support the hypothesis that blood samples from people with ME frequently contain altered T-cell receptor diversity

‘Just like talking to someone about like shit in your life and stuff, and they help you’: hopes and expectations for therapy among depressed adolescents

Objective: To explore hopes and expectations for therapy among a clinical population of depressed adolescents. Method: As part of a randomised clinical trial, 77 adolescents aged 11 to 17, with moderate to severe depression, were interviewed using a semi-structured interview schedule. The interviews were analysed qualitatively, using Framework Analysis. Results: The findings are reported around five themes: “The difficulty of imagining what will happen in therapy”, "the 'talking cure'"; “the therapist as doctor”, “therapy as a relationship” and “regaining the old self or developing new capacities”. Conclusions: Differing expectations are likely to have implications for the way young people engage with treatment, and failure to identify these expectations may lead to a risk of treatment breakdown

The Origin of the Hubble Sequence in Lambda-CDM Cosmology

The Galform semi-analytic model of galaxy formation is used to explore the mechanisms primarily responsible for the three types of galaxies seen in the local universe: bulge, bulge+disk and disk, identified with the visual morphological types E, S0/a-Sbc, and Sc-Scd, respectively. With a suitable choice of parameters the Galform model can accurately reproduce the observed local K_s-band luminosity function (LF) for galaxies split by visual morphological type. The successful set of model parameters is used to populate the Millennium Simulation with 9.4 million galaxies and their dark matter halos. The resulting catalogue is then used to explore the evolution of galaxies through cosmic history. The model predictions concur with recent observational results including the galaxy merger rate, the star formation rate and the seemingly anti-hierarchical evolution of ellipticals. However, the model also predicts significant evolution of the elliptical galaxy LF that is not observed. The discrepancy raises the possibility that samples of z~1 galaxies which have been selected using colour and morphological criteria may be contaminated with galaxies that are not actually ellipticals.Comment: Accepted for publication in MNRAS. Missing reference adde

Reframing Kurtz’s Painting: Colonial Legacies and Minority Rights in Ethnically Divided Societies

Minority rights constitute some of the most normatively and economically important human rights. Although the political science and legal literatures have proffered a number of constitutional and institutional design solutions to address the protection of minority rights, these solutions are characterized by a noticeable neglect of, and lack of sensitivity to, historical processes. This Article addresses that gap in the literature by developing a causal argument that explains diverging practices of minority rights protections as functions of colonial governments’ variegated institutional practices with respect to particular ethnic groups. Specifically, this Article argues that in instances where colonial governments politicize and institutionalize ethnic hegemony in the pre-independence period, an institutional legacy is created that leads to lower levels of minority rights protections. Conversely, a uniform treatment and depoliticization of ethnicity prior to independence ultimately minimizes ethnic cleavages post-independence and consequently causes higher levels of minority rights protections. Through a highly structured comparative historical analysis of Botswana and Ghana, this Article builds on a new and exciting research agenda that focuses on the role of long-term historio-structural and institutional influences on human rights performance and makes important empirical contributions by eschewing traditional methodologies that focus on single case studies that are largely descriptive in their analyses. Ultimately, this Article highlights both the strength of a historical approach to understanding current variations in minority rights protections and the varied institutional responses within a specific colonial government

“Did I bring it on myself?” An exploratory study of the beliefs that adolescents referred to mental health services have about the causes of their depression

Background: The causal beliefs which adults have regarding their mental health difficulties have been linked to help-seeking behaviour, treatment preferences and the outcome of therapy; yet the topic remains a relatively unexplored one in the adolescent literature. Aims: This exploratory study aims to explore the causal beliefs regarding depression among a sample of clinically referred adolescents. Design: 77 adolescents, aged between 11 and 17, all diagnosed with moderate to severe depression, were interviewed using a semi-structured interview schedule, at the beginning of their participation in a randomised controlled trial. Data were analysed qualitatively using Framework Analysis. Findings: The study identified three themes related to causal beliefs: 1) Bewilderment about why they were depressed; 2) Depression as a result of rejection, victimisation and stress; and 3) Something inside is to blame. Conclusion: Although some adolescents struggled to identify the causes of their depression, many identified stressful life experiences as the cause of their current depression. They also tended to emphasise their own negative ways of interpreting those events, and some believed that their depression was caused by something inside them. Adolescents’ causal beliefs are likely to have implications for the way they seek help and engage in treatment, making it important to understand how adolescents understand their difficulties

Otitis media in the Tgif knockout mouse implicates TGFβ signalling in chronic middle ear inflammatory disease

Otitis media with effusion (OME) is the most common cause of hearing loss in children and tympanostomy to alleviate the condition remains the commonest surgical intervention in children in the developed world. Chronic and recurrent forms of OM are known to have a very significant genetic component, however, until recently little was known of the underlying genes involved. The identification of mouse models of chronic OM has indicated a role of transforming growth factor beta (TGFβ) signalling and its impact on responses to hypoxia in the inflamed middle ear. We have, therefore, investigated the role of TGFβ signalling and identified and characterized a new model of chronic OM carrying a mutation in the gene for transforming growth interacting factor 1 (Tgif1). Tgif1 homozygous mutant mice have significantly raised auditory thresholds due to a conductive deafness arising from a chronic effusion starting at around 3 weeks of age. The OM is accompanied by a significant thickening of the middle ear mucosa lining, expansion of mucin-secreting goblet cell populations and raised levels of vascular endothelial growth factor, TNF-α and IL-1β in ear fluids. We also identified downstream effects on TGFβ signalling in middle ear epithelia at the time of development of chronic OM. Both phosphorylated SMAD2 and p21 levels were lowered in the homozygous mutant, demonstrating a suppression of the TGFβ pathway. The identification and characterization of the Tgif mutant supports the role of TGFβ signalling in the development of chronic OM and provides an important candidate gene for genetic studies in the human population

Early Predictors of Objectively Measured Physical Activity and Sedentary Behaviour in 8–10 Year Old Children: The Gateshead Millennium Study

With a number of studies suggesting associations between early life influences and later chronic disease risk, it is suggested that associations between early growth and later physical activity (PA) may be a mediator. However, conflicting evidence exists for association between birth weight and childhood PA. In addition, it is important to know what other, potentially modifiable, factors may influence PA in children given its' association with childhood and later adiposity. We used the Gateshead Millennium Study (GMS) to identify predictors of childhood PA levels. The GMS is a cohort of 1029 infants born in 1999–2000 in Gateshead in northern England. Throughout infancy and early childhood, detailed information was collected. Assessments at age 9 years included body composition, objective measures of habitual PA and a range of lifestyle factors. Mean total volumes of PA (accelerometer count per minute, cpm) and moderate-vigorous intensity PA (MVPA), and the percentage of time spent in sedentary behaviour (%SB) were quantified and related to potential predictors using linear regression and path analysis. Children aged 8–10 years were included. Significant differences were seen in all three outcome variables between sexes and season of measurement (p<0.001). Restricting children’s access to television was associated with decreased MVPA. Increased paternal age was associated with significant increases in %SB (p = 0.02), but not MVPA or total PA. Increased time spent in out of school sports clubs was significantly associated with decreased %SB (p = 0.02). No significant associations were seen with birth weight. A range of factors, directly or indirectly, influenced PA and sedentary behaviour. However, associations differed between the different constructs of PA and %SB. Exploring further the sex differences in PA would appear to be useful, as would encouraging children to join out of school sports clubs