Modelling the X-ray spectra of high velocity outflows from quasars

High velocity outflows from supermassive black holes have been invoked to explain the recent identification of strong absorption features in the hard X-ray spectra of several quasars. Here, Monte Carlo radiative transfer calculations are performed to synthesise X-ray spectra from models of such flows. It is found that simple, parametric bi-conical outflow models with plausible choices for the wind parameters predict spectra that are in good qualitative agreement with observations in the 2 - 10 keV band. The influence on the spectrum of both the mass-loss rate and opening angle of the flow are considered: the latter is important since photon leakage plays a significant role in establishing an ionization gradient within the flow, a useful discriminant between spherical and conical outflow for this and other applications. Particular attention is given to the bright quasar PG1211+143 for which constraints on the outflow geometry and mass-loss rate are discussed subject to the limitations of the currently available observational data.Comment: 15 pages, 8 figures. Accepted for publication by MNRA

Naturalistic language input is associated with resting-state functional connectivity in infancy

The quantity and quality of the language input that infants receive from their caregivers affects their future language abilities; however, it is unclear how variation in this input relates to preverbal brain circuitry. The current study investigated the relation between naturalistic language input and the functional connectivity (FC) of language networks in human infancy using resting-state functional magnetic resonance imaging (rsfMRI). We recorded the naturalistic language environments of five- to eight-month-old male and female infants using the Linguistic ENvironment Analysis (LENA) system and measured the quantity and consistency of their exposure to adult words (AWs) and adult-infant conversational turns (CTs). Infants completed an rsfMRI scan during natural sleep, and we examined FC among regions of interest (ROIs) previously implicated in language comprehension, including the auditory cortex, the left inferior frontal gyrus (IFG), and the bilateral superior temporal gyrus (STG). Consistent with theory of the ontogeny of the cortical language network (Skeide and Friederici, 2016), we identified two subnetworks posited to have distinct developmental trajectories: a posterior temporal network involving connections of the auditory cortex and bilateral STG and a frontotemporal network involving connections of the left IFG. Independent of socioeconomic status (SES), the quantity of CTs was uniquely associated with FC of these networks. Infants who engaged in a larger number of CTs in daily life had lower connectivity in the posterior temporal language network. These results provide evidence for the role of vocal interactions with caregivers, compared with overheard adult speech, in the function of language networks in infancy

Audit of head injury management in Accident and Emergency at two hospitals: implications for NICE CT guidelines

BACKGROUND: The National Institute for Clinical Excellence (NICE) has produced guidelines on the early management of head injury. This study audits the process of the management of patients with head injury presenting at Accident and Emergency (A&E) departments and examines the impact upon resources of introducing NICE guidelines for eligibility of a CT scan. METHODS: A retrospective audit of consecutive patients of any age, presenting at A&E with a complaint of head injury during one month in two northern District General Hospitals forming part of a single NHS Trust. RESULTS: 419 patients presented with a median age of 15.5 years, and 61% were male. 58% had a Glasgow Coma Score (GCS) recorded and 33 (8%) were admitted. Only four of the ten indicators for a CT scan were routinely assessed, but data were complete for only one (age), and largely absent for another (vomiting). Using just three (incomplete) indicators showed a likely 4 fold increase in the need for a CT scan. CONCLUSIONS: The majority of patients who present with a head injury to Accident and Emergency departments are discharged home. Current assessment processes and associated data collection routines do not provide the information necessary to implement NICE guidelines for CT brain scans. The development of such clinical audit systems in a busy A&E department is likely to require considerable investment in technology and/or staff. The resource implications for radiology are likely to be substantial

Multi-dimensional modelling of X-ray spectra for AGN accretion-disk outflows

We use a multi-dimensional Monte Carlo code to compute X-ray spectra for a variety of active galactic nucleus (AGN) disk-wind outflow geometries. We focus on the formation of blue-shifted absorption features in the Fe K band and show that line features similar to those which have been reported in observations are often produced for lines-of-sight through disk-wind geometries. We also discuss the formation of other spectral features in highly ionized outflows. In particular we show that, for sufficiently high wind densities, moderately strong Fe K emission lines can form and that electron scattering in the flow may cause these lines to develop extended red wings. We illustrate the potential relevance of such models to the interpretation of real X-ray data by comparison with observations of a well-known AGN, Mrk 766.Comment: 15 pages, 13 figures, accepted for publication by MNRA

Dynamical Modeling of the Stellar Nucleus of M31

We present stellar dynamical models of the lopsided, double-peaked nucleus of M31, derived from Hubble Space Telescope (HST) photometry. A Schwarzscild-type method, in conjunction with Richardson-Lucy deconvolution, was employed to construct steadily rotating, hot, stellar disks. The stars orbit a massive dark object, on prograde and retrograde quasi-periodic loop orbits. Our results support Tremaine's eccentric disk model, extended to include a more massive disk, non zero pattern speed ($\Omega$), and different viewing angle. Most of the disk mass populated prograde orbits, with $\simeq 3.4$ on retrograde orbits. The best fits to photometric and kinematic maps were disks with \Omega\approx 16\kmspc . We speculate on the origins of the lopsidedness, invoking recent work on the linear overstability of nearly Keplerian disks, that possess even a small amount of a counter-rotating component. Accretion of material-no more massive than a globular cluster-onto a preexisting stellar disk, will account for the mass in our retrograde orbits, and could have stimulated the lopsidedness seen in the nucleus of M31.Comment: 6 pages, 5 figures, revised. To appear in Astronomy and Astrophysic

The quiescent light curve and evolutionary state of GRO J1655-40

We present ellipsoidal light-curve fits to the quiescent B, V, R and I light curves of GRO J1655-40 (Nova Scorpii 1994). The fits are based on a simple model consisting of a Roche-lobe filling secondary and an accretion disc around the black-hole primary. Unlike previous studies, no assumptions are made about the interstellar extinction or the distance to the source; instead these are determined self-consistently from the observed light curves. In order to obtain tighter limits on the model parameters, we used the distance determination from the kinematics of the radio jet as an additional constraint. We obtain a value for the extinction that is lower than was assumed previously; this leads to lower masses for both the black hole and the secondary star of 5.4 +/- 0.3 Msun and 1.45 +/- 0.35 Msun, respectively. The errors in the determination of the model parameters are dominated by systematic errors, in particular due to uncertainties in the modeling of the disk structure and uncertainties in the atmosphere model for the chemically anomalous secondary in the system. A lower mass of the secondary naturally explains the transient nature of the system if it is either in a late case A or early case B mass-transfer phase.Comment: 12 pages, 4 figures, submitted to MNRA

Individual variation in hunger, energy intake and ghrelin responses to acute exercise

Purpose This study aimed to characterize the immediate and extended effect of acute exercise on hunger, energy intake, and circulating acylated ghrelin concentrations using a large data set of homogenous experimental trials and to describe the variation in responses between individuals. Methods Data from 17 of our group's experimental crossover trials were aggregated yielding a total sample of 192 young, healthy males. In these studies, single bouts of moderate to high-intensity aerobic exercise (69% ± 5% V˙O2 peak; mean ± SD) were completed with detailed participant assessments occurring during and for several hours postexercise. Mean hunger ratings were determined during (n = 178) and after (n = 118) exercise from visual analog scales completed at 30-min intervals, whereas ad libitum energy intake was measured within the first hour after exercise (n = 60) and at multiple meals (n = 128) during the remainder of trials. Venous concentrations of acylated ghrelin were determined at strategic time points during (n = 118) and after (n = 89) exercise. Results At group level, exercise transiently suppressed hunger (P < 0.010, Cohen's d = 0.77) but did not affect energy intake. Acylated ghrelin was suppressed during exercise (P < 0.001, Cohen's d = 0.10) and remained significantly lower than control (no exercise) afterward (P < 0.024, Cohen's d = 0.61). Between participants, there were notable differences in responses; however, a large proportion of this spread lay within the boundaries of normal variation associated with biological and technical assessment error. Conclusion In young men, acute exercise suppresses hunger and circulating acylated ghrelin concentrations with notable diversity between individuals. Care must be taken to distinguish true interindividual variation from random differences within normal limits

Adding web-based behavioural support to exercise referral schemes for inactive adults with chronic health conditions: the e-coachER Randomised Controlled Trial

BACKGROUND: There is modest evidence that exercise referral schemes increase physical activity in inactive individuals with chronic health conditions. There is a need to identify additional ways to improve the effects of exercise referral schemes on long-term physical activity. OBJECTIVES: To determine if adding the e-coachER intervention to exercise referral schemes is more clinically effective and cost-effective in increasing physical activity after 1 year than usual exercise referral schemes. DESIGN: A pragmatic, multicentre, two-arm randomised controlled trial, with a mixed-methods process evaluation and health economic analysis. Participants were allocated in a 1 : 1 ratio to either exercise referral schemes plus e-coachER (intervention) or exercise referral schemes alone (control). SETTING: Patients were referred to exercise referral schemes in Plymouth, Birmingham and Glasgow. PARTICIPANTS: There were 450 participants aged 16-74 years, with a body mass index of 30-40 kg/m2, with hypertension, prediabetes, type 2 diabetes, lower limb osteoarthritis or a current/recent history of treatment for depression, who were also inactive, contactable via e-mail and internet users. INTERVENTION: e-coachER was designed to augment exercise referral schemes. Participants received a pedometer and fridge magnet with physical activity recording sheets, and a user guide to access the web-based support in the form of seven 'steps to health'. e-coachER aimed to build the use of behavioural skills (e.g. self-monitoring) while strengthening favourable beliefs in the importance of physical activity, competence, autonomy in physical activity choices and relatedness. All participants were referred to a standard exercise referral scheme. PRIMARY OUTCOME MEASURE: Minutes of moderate and vigorous physical activity in ≥ 10-minute bouts measured by an accelerometer over 1 week at 12 months, worn ≥ 16 hours per day for ≥ 4 days including ≥ 1 weekend day. SECONDARY OUTCOMES: Other accelerometer-derived physical activity measures, self-reported physical activity, exercise referral scheme attendance and EuroQol-5 Dimensions, five-level version, and Hospital Anxiety and Depression Scale scores were collected at 4 and 12 months post randomisation. RESULTS: Participants had a mean body mass index of 32.6 (standard deviation) 4.4 kg/m2, were referred primarily for weight loss and were mostly confident self-rated information technology users. Primary outcome analysis involving those with usable data showed a weak indicative effect in favour of the intervention group (n = 108) compared with the control group (n = 124); 11.8 weekly minutes of moderate and vigorous physical activity (95% confidence interval -2.1 to 26.0 minutes; p = 0.10). Sixty-four per cent of intervention participants logged on at least once; they gave generally positive feedback on the web-based support. The intervention had no effect on other physical activity outcomes, exercise referral scheme attendance (78% in the control group vs. 75% in the intervention group) or EuroQol-5 Dimensions, five-level version, or Hospital Anxiety and Depression Scale scores, but did enhance a number of process outcomes (i.e. confidence, importance and competence) compared with the control group at 4 months, but not at 12 months. At 12 months, the intervention group incurred an additional mean cost of £439 (95% confidence interval -£182 to £1060) compared with the control group, but generated more quality-adjusted life-years (mean 0.026, 95% confidence interval 0.013 to 0.040), with an incremental cost-effectiveness ratio of an additional £16,885 per quality-adjusted life-year. LIMITATIONS: A significant proportion (46%) of participants were not included in the primary analysis because of study withdrawal and insufficient device wear-time, so the results must be interpreted with caution. The regression model fit for the primary outcome was poor because of the considerable proportion of participants [142/243 (58%)] who recorded no instances of ≥ 10-minute bouts of moderate and vigorous physical activity at 12 months post randomisation. FUTURE WORK: The design and rigorous evaluation of cost-effective and scalable ways to increase exercise referral scheme uptake and maintenance of moderate and vigorous physical activity are needed among patients with chronic conditions. CONCLUSIONS: Adding e-coachER to usual exercise referral schemes had only a weak indicative effect on long-term rigorously defined, objectively assessed moderate and vigorous physical activity. The provision of the e-coachER support package led to an additional cost and has a 63% probability of being cost-effective based on the UK threshold of £30,000 per quality-adjusted life-year. The intervention did improve some process outcomes as specified in our logic model. TRIAL REGISTRATION: Current Controlled Trials ISRCTN15644451. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 24, No. 63. See the NIHR Journals Library website for further project information.</p

Type Ia Supernova Explosion Models

Because calibrated light curves of Type Ia supernovae have become a major tool to determine the local expansion rate of the Universe and also its geometrical structure, considerable attention has been given to models of these events over the past couple of years. There are good reasons to believe that perhaps most Type Ia supernovae are the explosions of white dwarfs that have approached the Chandrasekhar mass, M_ch ~ 1.39 M_sun, and are disrupted by thermonuclear fusion of carbon and oxygen. However, the mechanism whereby such accreting carbon-oxygen white dwarfs explode continues to be uncertain. Recent progress in modeling Type Ia supernovae as well as several of the still open questions are addressed in this review. Although the main emphasis will be on studies of the explosion mechanism itself and on the related physical processes, including the physics of turbulent nuclear combustion in degenerate stars, we also discuss observational constraints.Comment: 38 pages, 4 figures, Annual Review of Astronomy and Astrophysics, in pres

A Call to Action: Taking the Untenable out of Women Professors’ Pregnancy, Postpartum, and Caregiving Demands

Despite becoming increasingly represented in academic departments, women scholars face a critical lack of support as they navigate demands pertaining to pregnancy, motherhood, and child caregiving. In addition, cultural norms surrounding how faculty and academic leaders discuss and talk about tenure, promotion, and career success have created pressure for women who wish to grow their family and care for their children, leading to questions about whether it is possible for these women to have a family and an academic career. The current paper is a call to action for academia to build structures that support women professors as they navigate the complexities of pregnancy, the postpartum period, and the caregiving demands of their children. We specifically call on those of us in I-O psychology, management, and related departments to lead the way. In making this call, we first present the realistic, moral, and financial cases for why this issue needs to be at the forefront of discussions surrounding success in the academy. We then discuss how in the U.S. and elsewhere, an absence of policies supporting women places two groups of academics—department heads (as the leaders of departments who have discretion outside of formal policies to make work better for women) and other faculty members (as potential allies both in the department and within our professional organizations)—in a critical position to enact support and change. We conclude with our boldest call—to make a cultural shift that shatters the assumption that having a family is not compatible with academic success. Combined, we seek to launch a discussion that leads directly to necessary and overdue changes in how women scholars are supported in academia