235 research outputs found
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 (), and different viewing angle. Most of
the disk mass populated prograde orbits, with 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
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
Estimating Incidence Curves of Several Infections Using Symptom Surveillance Data
We introduce a method for estimating incidence curves of several co-circulating infectious pathogens, where each infection has its own probabilities of particular symptom profiles. Our deconvolution method utilizes weekly surveillance data on symptoms from a defined population as well as additional data on symptoms from a sample of virologically confirmed infectious episodes. We illustrate this method by numerical simulations and by using data from a survey conducted on the University of Michigan campus. Last, we describe the data needs to make such estimates accurate
Mass drug administration of ivermectin, diethylcarbamazine, plus albendazole compared with diethylcarbamazine plus albendazole for reduction of lymphatic filariasis endemicity in Papua New Guinea: a cluster-randomised trial
Background: A single co-administered dose of a triple-drug regimen (ivermectin, diethylcarbamazine, and albendazole) has been shown to be safe and more efficacious for clearing Wuchereria bancrofti microfilariae than the standard two-drug regimen of diethylcarbamazine plus albendazole in clinical trials. However, the effectiveness of mass drug administration with the triple-drug regimen compared with the two-drug regimen is unknown. We compared the effectiveness of mass drug administration with the triple-drug and two-drug regimens for reducing microfilariae prevalence to less than 1% and circulating filarial antigen prevalence to less than 2%, levels that are unlikely to sustain transmission of lymphatic filariasis, in Papua New Guinea.
Methods: This open-label, cluster-randomised study was done in 24 villages in a district endemic for lymphatic filariasis in Papua New Guinea. Villages paired by population size were randomly assigned to receive mass drug administration with a single dose of the triple-drug oral regimen of ivermectin (200 μg per kg of bodyweight) plus diethylcarbamazine (6 mg per kg of bodyweight) plus albendazole (400 mg) or a single dose of the two-drug oral regimen of diethylcarbamazine (6 mg per kg of bodyweight) plus albendazole (400 mg). This is a follow-on study of a previously reported safety study (ClinicalTrials.gov NCT02899936). All residents aged 5 years or older and non-pregnant women were asked to participate. After cross-sectional night blood microfilariae and circulating filarial antigen surveys, mass drug administration was provided at baseline and repeated 12 months later. The primary outcomes were mean prevalence of microfilariae and circulating filarial antigen at 12 months and 24 months, assessed in all residents willing to participate at each timepoint. This study is registered with ClinicalTrials.gov, NCT03352206.
Findings: Between Nov 18, 2016, and May 26, 2017, 4563 individuals were enrolled in 24 clusters; 12 clusters (2382 participants) were assigned to the triple-drug regimen and 12 clusters (2181 participants) to the two-drug regimen. Mean drug ingestion rates (of residents aged ≥5 years) were 66·1% at baseline and 63·2% at 12 months in communities assigned to the triple-drug regimen and 65·9% at baseline and 54·9% at 12 months in communities assigned to the two-drug regimen. Microfilariae prevalence in the triple-drug regimen group decreased from 105 (4·4%) of 2382 participants (95% CI 3·6–5·3) at baseline to nine (0·4%) of 2319 (0·1–0·7) at 12 months and four (0·2%) of 2086 (0·1–0·5) at 24 months. In the two-drug regimen group, microfilariae prevalence decreased from 93 (4·3%) of 2181 participants (95% CI 3·5–5·2) at baseline to 29 (1·5%) of 1963 (1·0–2·1) at 12 months and eight (0·4%) of 1844 (0·2–0·9) at 24 months (adjusted estimated risk ratio 4·5, 95% CI 1·4–13·8, p=0·0087, at 12 months; 2·9, 95% CI 1·0–8·8, p=0·058, at 24 months). The prevalence of circulating filarial antigen decreased from 523 (22·0%) of 2382 participants (95% CI 20·3–23·6) at baseline to 378 (16·3%) of 2319 (14·9–17·9) at 12 months and 156 (7·5%) of 2086 (6·4–8·7) at 24 months in the triple-drug regimen group and from 489 (22·6%) of 2168 participants (20·7–24·2) at baseline to 358 (18·2%) of 1963 (16·7–20·1) at 12 months and 184 (10·0%) of 1840 (8·7–11·5) at 24 months in the two-drug regimen group; after adjustment, differences between groups were not significant.
Interpretation: Mass administration of the triple-drug regimen was more effective than the two-drug regimen in reducing microfilariae prevalence in communities to less than the target level of 1%, but did not reduce circulating filarial antigen prevalence to less than 2%. These results support the use of mass drug administration with the triple-drug regimen to accelerate elimination of lymphatic filariasis
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