1,228 research outputs found
X-ray Observations of the Compact Source in CTA 1
The point source RX J0007.0+7302, at the center of supernova remnant CTA 1,
was studied using the X-Ray Multi-mirror Mission. The X-ray spectrum of the
source is consistent with a neutron star interpretation, and is well described
by a power law with the addition of a soft thermal component that may
correspond to emission from hot polar cap regions or to cooling emission from a
light element atmosphere over the entire star. There is evidence of extended
emission on small spatial scales which may correspond to structure in the
underlying synchrotron nebula. No pulsations are observed. Extrapolation of the
nonthermal spectrum of RX J0007.0+7302 to gamma-ray energies yields a flux
consistent with that of EGRET source 3EG J0010+7309, supporting the proposition
that there is a gamma-ray emitting pulsar at the center of CTA 1. Observations
of the outer regions of CTA 1 with the Advanced Satellite for Cosmology and
Astrophysics confirm earlier detections of thermal emission from the remnant
and show that the synchrotron nebula extends to the outermost reaches of the
SNR.Comment: 5 pages, including 4 postscript figs.LaTex. Accepted for publication
by Ap
Chandra Observations of the Crab-like Supernova Remnant G21.5-0.9
Chandra observations of the Crab-like supernova remnant G21.5-0.9 reveal a
compact central core and spectral variations indicative of synchrotron burn-off
of higher energy electrons in the inner nebula. The central core is slightly
extended, perhaps indicating the presence of an inner wind-shock nebula
surrounding the pulsar. No pulsations are observed from the central region,
yielding an upper limit of ~40% for the pulsed fraction. A faint outer shell
may be the first evidence of the expanding ejecta and blast wave formed in the
initial explosion, indicating a composite nature for G21.5-0.9.Comment: 4 pages, 2 figures, formatted with emulateapj, submitted to ApJ
Primary care consultations and costs among HIV-positive individulas in UK primary care 1995-2005: a cohort study
Objectives: To investigate the role of primary care in the management of HIV and estimate primary care-associated costs at a time of rising prevalence.
Methods: Retrospective cohort study between 1995 and 2005, using data from general practices contributing data to the UK General Practice Research Database. Patterns of consultation and morbidity and associated consultation costs were analysed among all practice-registered patients for whom HIV-positive status was recorded in the general practice record.
Results: 348 practices yielded 5504 person-years (py) of follow-up for known HIV-positive patients, who consult in general practice frequently (4.2 consultations/py by men, 5.2 consultations/py by women, in 2005) for a range of conditions. Consultation rates declined in the late 1990s from 5.0 and 7.3 consultations/py in 1995 in men and women, respectively, converging to rates similar to the wider population. Costs of consultation (general practitioner and nurse, combined) reflect these changes, at ÂŁ100.27 for male patients and ÂŁ117.08 for female patients in 2005. Approximately one in six medications prescribed in primary care for HIV-positive individuals has the potential for major interaction with antiretroviral medications.
Conclusion: HIV-positive individuals known in general practice now consult on a similar scale to the wider population. Further research should be undertaken to explore how primary care can best contribute to improving the health outcomes of this group with chronic illness. Their substantial use of primary care suggests there may be potential to develop effective integrated care pathways
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UniFHy v0.1.1: a community modelling framework for the terrestrial water cycle in Python
The land surface, hydrological, and groundwater modelling communities all have expertise in simulating the hydrological processes at play in the terrestrial component of the Earth system. However, these communities, and the wider Earth system modelling community, have largely remained distinct with limited collaboration between disciplines, hindering progress in the representation of hydrological processes in the land component of Earth system models (ESMs). In order to address key societal questions regarding the future availability of water resources and the intensity of extreme events such as floods and droughts in a changing climate, these communities must come together and build on the strengths of one another to produce next-generation land system models that are able to adequately simulate the terrestrial water cycle under change. The development of a common modelling infrastructure can contribute to stimulating cross-fertilisation by structuring and standardising the interactions. This paper presents such an infrastructure, a land system framework, which targets an intermediate level of complexity and constrains interfaces between components (and communities) and, in doing so, aims to facilitate an easier pipeline between the development of (sub-)community models and their integration, both for standalone use and for use in ESMs. This paper first outlines the conceptual design and technical capabilities of the framework; thereafter, its usage and useful characteristics are demonstrated through case studies. The main innovations presented here are (1)Â the interfacing constraints themselves; (2)Â the implementation in Python (the Unified Framework for Hydrology, unifhy); and (3)Â the demonstration of standalone use cases using the framework. The existing framework does not yet meet all our goals, in particular, of directly supporting integration into larger ESMs, so we conclude with the remaining limitations of the current framework and necessary future developments.</p
Narrative explorations into the professional development of lecturers teaching higher education in English further education colleges
The diversification of settings in which higher education is delivered has resulted in a growing proportion of lecturers entering teaching from professional backgrounds. This is a challenging transition as lecturers are rarely given the space to consider the implications of this move on their identities and practice styles. Writing is recognised as a powerful methodology through which individuals can make sense of experiences and conceptualise them in light of historical, theoretical and social perspectives. In this paper we consider the experiences of 10 college lecturers who used writing to explore this transition as part of a professional development initiative to promote their writing skills. They were providing higher education in further education colleges across South West England. This project ran over two years, involving a year-long professional development intervention and a subsequent evaluation. Over this time the lecturers produced a number of written pieces. We present the different styles and forms of writing used, and how these engaged with their emergent voices and growing sense of legitimacy. We highlight how writing can provide a reflexive medium and assist in the identification of developmental goals, something particularly valuable during professional transitions
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Outcomes of preimplantation genetic diagnosis in neurofibromatosis type 1
Objective
To examine the effect of patient and facility level factors on the success of preimplantation genetic diagnosis (PGD) in patients with neurofibromatosis 1 (NF1).
Design
Retrospective review.
Setting
Large PGD reference laboratory.
Patient(s)
All patients with NF1 referred from June 2004 to May 2013.
Intervention(s)
None.
Main Outcome Measure(s)
Embryos' NF1 mutation status and live birth rates.
Result(s)
Seventy-seven couples underwent 156 PGD cycles during the study period. The average maternal age at the time of embryo biopsy was 33.2 years. The majority of embryos had a day 3 single blastomere biopsy without aneuploidy screening. A diagnosis was obtained for 80% of biopsied embryos; 20% of biopsies were nondiagnostic due to technical failures. Diagnosis was more often obtained for embryos of parents with familial disease and for embryos biopsied at centers that referred multiple NF1 cases. Among diagnosed embryos, 483/1,060 (46%) were unaffected by the parental NF1 mutation. Twenty-two (14%) of the 156 cycles had a confirmed live birth; if the observed success rate is applied to cycles with unknown outcomes, 33/156 (21%) cycles are expected to have resulted in live birth. In multivariate logistic regression, having a live birth was significantly associated with having more unaffected embryos available for transfer (odds ratio 1.33 per additional embryo, 95% confidence interval 1.02â1.72).
Conclusion(s)
Advances in biopsy and diagnostic techniques which increase the number of unaffected embryos identified may improve live birth rates for patients with NF1. Clinicians should counsel patients about their fertility and reproductive options early, with the use of disease-specific data, to set appropriate expectations for the PGD process
Destabilization of the thermohaline circulation by transient perturbations to the hydrological cycle
We reconsider the problem of the stability of the thermohaline circulation as
described by a two-dimensional Boussinesq model with mixed boundary conditions.
We determine how the stability properties of the system depend on the intensity
of the hydrological cycle. We define a two-dimensional parameters' space
descriptive of the hydrology of the system and determine, by considering
suitable quasi-static perturbations, a bounded region where multiple equilibria
of the system are realized. We then focus on how the response of the system to
finite-amplitude surface freshwater forcings depends on their rate of increase.
We show that it is possible to define a robust separation between slow and fast
regimes of forcing. Such separation is obtained by singling out an estimate of
the critical growth rate for the anomalous forcing, which can be related to the
characteristic advective time scale of the system.Comment: 37 pages, 8 figures, submitted to Clim. Dy
Manipulating ultracold atoms with a reconfigurable nanomagnetic system of domain walls
The divide between the realms of atomic-scale quantum particles and
lithographically-defined nanostructures is rapidly being bridged. Hybrid
quantum systems comprising ultracold gas-phase atoms and substrate-bound
devices already offer exciting prospects for quantum sensors, quantum
information and quantum control. Ideally, such devices should be scalable,
versatile and support quantum interactions with long coherence times.
Fulfilling these criteria is extremely challenging as it demands a stable and
tractable interface between two disparate regimes. Here we demonstrate an
architecture for atomic control based on domain walls (DWs) in planar magnetic
nanowires that provides a tunable atomic interaction, manifested experimentally
as the reflection of ultracold atoms from a nanowire array. We exploit the
magnetic reconfigurability of the nanowires to quickly and remotely tune the
interaction with high reliability. This proof-of-principle study shows the
practicability of more elaborate atom chips based on magnetic nanowires being
used to perform atom optics on the nanometre scale.Comment: 4 pages, 4 figure
Patient-level predictors of detection of depressive symptoms, referral, and uptake of depression counseling among chronic care patients in KwaZulu-Natal, South Africa
Background: Integration of depression treatment into primary care could improve patient outcomes in low-resource settings. Losses along the depression care cascade limit integrated service effectiveness. This study identified patient-level factors that predicted detection of depressive symptoms by nurses, referral for depression treatment, and uptake of counseling, as part of integrated care in KwaZulu-Natal, South Africa. Methods: This was an analysis of baseline data from a prospective cohort. Participants were adult patients with at least moderate depressive symptoms at primary care facilities in Amajuba, KwaZulu-Natal, South Africa. Participants were screened for depressive symptoms prior to routine assessment by a nurse. Generalized linear mixed-effects models were used to estimate associations between patient characteristics and service delivery outcomes. Results: Data from 412 participants were analyzed. Nurses successfully detected depressive symptoms in 208 [50.5%, 95% confidence interval (CI) 38.9-62.0] participants; of these, they referred 76 (36.5%, 95% CI 20.3-56.5) for depression treatment; of these, 18 (23.7%, 95% CI 10.7-44.6) attended at least one session of depression counseling. Depressive symptom severity, alcohol use severity, and perceived stress were associated with detection. Similar factors did not drive referral or counseling uptake. Conclusions: Nurses detected patients with depressive symptoms at rates comparable to primary care providers in high-resource settings, though gaps in referral and uptake persist. Nurses were more likely to detect symptoms among patients in more severe mental distress. Implementation strategies for integrated mental health care in low-resource settings should target improved rates of detection, referral, and uptake
The cellular and synaptic architecture of the mechanosensory dorsal horn
The deep dorsal horn is a poorly characterized spinal cord region implicated in processing low-threshold mechanoreceptor (LTMR) information. We report an array of mouse genetic tools for defining neuronal components and functions of the dorsal horn LTMR-recipient zone (LTMR-RZ), a role for LTMR-RZ processing in tactile perception, and the basic logic of LTMR-RZ organization. We found an unexpectedly high degree of neuronal diversity in the LTMR-RZ: seven excitatory and four inhibitory subtypes of interneurons exhibiting unique morphological, physiological, and synaptic properties. Remarkably, LTMRs form synapses on between four and 11 LTMR-RZ interneuron subtypes, while each LTMR-RZ interneuron subtype samples inputs from at least one to three LTMR classes, as well as spinal cord interneurons and corticospinal neurons. Thus, the LTMR-RZ is a somatosensory processing region endowed with a neuronal complexity that rivals the retina and functions to pattern the activity of ascending touch pathways that underlie tactile perception
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