78 research outputs found
The effect of a strong external radiation field on protostellar envelopes in Orion
We discuss the effects of an enhanced interstellar radiation field (ISRF) on
the observables of protostellar cores in the Orion cloud region. Dust radiative
transfer is used to constrain the envelope physical structure by reproducing
SCUBA 850 micron emission. Previously reported 13CO, C17O and H2CO line
observations are reproduced through detailed Monte Carlo line radiative
transfer models. It is found that the 13CO line emission is marginally
optically thick and sensitive to the physical conditions in the outer envelope.
An increased temperature in this region is needed in order to reproduce the
13CO line strengths and it is suggested to be caused by a strong heating from
the exterior, corresponding to an ISRF in Orion 10^3 times stronger than the
"standard" ISRF. The typical temperatures in the outer envelope are higher than
the desorption temperature for CO. The C17O emission is less sensitive to this
increased temperature but rather traces the bulk envelope material. The data
are only fit by a model where CO is depleted, except in the inner and outermost
regions where the temperature increases above 30-40 K. The fact that the
temperatures do not drop below approximately 25 K in any of the envelopes
whereas a significant fraction of CO is frozen-out suggest that the
interstellar radiation field has changed through the evolution of the cores.
The H2CO lines are successfully reproduced in the model of an increased ISRF
with constant abundances of 3-5x10^{-10}.Comment: 11 pages, 10 figures. Accepted for publication in A&
Experience and response to a randomised controlled trial of extended-release injectable buprenorphine versus sublingual tablet buprenorphine and oral liquid methadone for opioid use disorder:protocol for a mixed-methods evaluation
INTRODUCTION: Opioid use disorder (OUD) is a debilitating and persistent disorder. The standard-of-care treatment is daily maintenance dosing of sublingual buprenorphine (BUP-SL) or oral methadone (MET). Monthly, extended-release, subcutaneous injectable buprenorphine (BUP-XR) has been developed to enhance treatment effectiveness. This study aims to investigate the experiences of participants who have been offered BUP-XR (evaluation 1), health-related quality-of-life among participants who have opted to receive BUP-XR longer term (evaluation 2) and the experiences of participants allocated to receive BUP-XR or BUP-SL or MET with the offer of adjunctive personalised psychosocial intervention (evaluation 3). METHODS AND ANALYSIS: Three qualitative–quantitative (mixed-methods) evaluations embedded in a five-centre, head-to-head, randomised controlled trial of BUP-XR versus BUP-SL and MET in the UK. Evaluation 1 is a four-centre interview anchored on an OUD-related topic guide and conducted after the 24-week trial endpoint. Evaluation 2 is a two-centre interview anchored on medications for opioid use disorder-specific quality-of-life topic guide conducted among participants after 12–24 months. Evaluation 3: single-centre interview after the 24-week trial endpoint. All evaluations include selected trial clinical measures, with evaluation 2 incorporating additional questionnaires. Target participant recruitment for evaluations 1 and 2 is 15 participants per centre (n=60 and n=30, respectively). Recruitment for evaluation 3 is 15 participants per treatment arm (n=30). Each evaluation will be underpinned by theory, drawing on constructs from the behavioural model for health service use or the health-related quality-of-life model. Qualitative data analysis will be by iterative categorisation. ETHICS AND DISSEMINATION: Study protocol, consent materials and questionnaires were approved by the London-Brighton and Sussex research ethics committee (reference: 19/LO/0483) and the Health Research Authority (IRAS project number 255522). Participants will be provided with information sheets and informed written consent will be obtained for each evaluation. Study findings will be disseminated through peer-reviewed scientific journals. TRIAL REGISTRATION NUMBER: 2018-004460-63
A Candidate Dual QSO at Cosmic Noon
We report the discovery of a candidate dual QSO at z=1.889, a redshift that
is in the era known as "cosmic noon" where most of the Universe's black hole
and stellar mass growth occurred. The source was identified in Hubble Space
Telescope WFC3/IR images of a dust-reddened QSO that showed two
closely-separated point sources at a projected distance of 0.26", or 2.2 kpc.
This red QSO was targeted for imaging to explore whether red QSOs are hosted by
merging galaxies. We subsequently obtained a spatially-resolved STIS spectrum
of the system, covering the visible spectral range, and verifying the presence
of two distinct QSO components. We also obtained high-resolution radio
continuum observations with the VLBA at 1.4 GHz (21-cm L band) and found two
sources coincident with the optical positions. The sources have similar black
hole masses, bolometric luminosities, and radio loudness parameters. However,
their colors and reddenings differ significantly. The redder QSO has a higher
Eddington ratio, consistent with previous findings. We consider the possibility
of gravitational lensing and and find that it would require extreme and
unlikely conditions. If confirmed as a bona-fide dual QSO, this system would
link dust-reddening to galaxy and supermassive black hole mergers, opening up a
new population in which to search for samples of dual AGN.Comment: Accepted for publication in ApJ Letter
CCAT-prime: Science with an Ultra-widefield Submillimeter Observatory at Cerro Chajnantor
We present the detailed science case, and brief descriptions of the telescope
design, site, and first light instrument plans for a new ultra-wide field
submillimeter observatory, CCAT-prime, that we are constructing at a 5600 m
elevation site on Cerro Chajnantor in northern Chile. Our science goals are to
study star and galaxy formation from the epoch of reionization to the present,
investigate the growth of structure in the Universe, improve the precision of
B-mode CMB measurements, and investigate the interstellar medium and star
formation in the Galaxy and nearby galaxies through spectroscopic,
polarimetric, and broadband surveys at wavelengths from 200 um to 2 mm. These
goals are realized with our two first light instruments, a large field-of-view
(FoV) bolometer-based imager called Prime-Cam (that has both camera and an
imaging spectrometer modules), and a multi-beam submillimeter heterodyne
spectrometer, CHAI. CCAT-prime will have very high surface accuracy and very
low system emissivity, so that combined with its wide FoV at the unsurpassed
CCAT site our telescope/instrumentation combination is ideally suited to pursue
this science. The CCAT-prime telescope is being designed and built by Vertex
Antennentechnik GmbH. We expect to achieve first light in the spring of 2021.Comment: Presented at SPIE Millimeter, Submillimeter, and Far-Infrared
Detectors and Instrumentation for Astronomy IX, June 14th, 201
Demedicalising misery: Welcoming the human paradigm in mental health nurse education
To date, no genes, biomarkers or evidence for disease processes have been convincingly identified for functional mental health problems. Instead, an overwhelming amount of evidence points to the causal role of social and relational adversities in their developmentt. A change of language is needed to understand, conceptualise, research and help in alleviating human misery. In moving from technological to human paradigmatic understandings, narrative-based approaches, including the central role of formulation, emerge as a more credible way forward
Herschel observations of extra-ordinary sources: Detecting spiral arm clouds by CH absorption lines
We have observed CH absorption lines ()
against the continuum source Sgr~B2(M) using the \textit{Herschel}/HIFI
instrument. With the high spectral resolution and wide velocity coverage
provided by HIFI, 31 CH absorption features with different radial velocities
and line widths are detected and identified. The narrower line width and lower
column density clouds show `spiral arm' cloud characteristics, while the
absorption component with the broadest line width and highest column density
corresponds to the gas from the Sgr~B2 envelope. The observations show that
each `spiral arm' harbors multiple velocity components, indicating that the
clouds are not uniform and that they have internal structure. This
line-of-sight through almost the entire Galaxy offers unique possibilities to
study the basic chemistry of simple molecules in diffuse clouds, as a variety
of different cloud classes are sampled simultaneously. We find that the linear
relationship between CH and H column densities found at lower by UV
observations does not continue into the range of higher visual extinction.
There, the curve flattens, which probably means that CH is depleted in the
denser cores of these clouds.Comment: Accepted for publication in A&A, HIFI Special Issu
Politicians, experts, and patient representatives call for the UK government to reverse the rate of antidepressant prescribing.
Recommended from our members
Aging is associated with a prefrontal lateral-medial shift during picture-induced negative affect
The capacity to adaptively respond to negative emotion is in part dependent upon lateral areas of the prefrontal cortex (PFC). Lateral PFC areas are particularly susceptible to age-related atrophy, which affects executive function (EF). We used structural and functional magnetic resonance imaging (MRI) to test the hypothesis that older age is associated with greater medial PFC engagement during processing of negative information, and that this engagement is dependent upon the integrity of grey matter structure in lateral PFC as well as EF. Participants (n = 64, 38–79 years) viewed negative and neutral scenes while in the scanner, and completed cognitive tests as part of a larger study. Grey matter probability (GMP) was computed to index grey matter integrity. FMRI data demonstrated less activity in the left ventrolateral PFC (VLPFC) and greater ventromedial PFC (VMPFC) activity with increasing age during negative-picture viewing. Age did not correlate with amygdala responding. GMP in VLPFC and EF were negatively associated with VMPFC activity. We conclude that this change from lateral to medial PFC engagement in response to picture-induced negative affect reflects decreased reliance on executive function-related processes, possibly associated with reduced grey matter in lateral PFC, with advancing age to maintain emotional functioning
Speech-evoked activation in adult temporal cortex measured using functional near-infrared spectroscopy (fNIRS): Are the measurements reliable?
Functional near-infrared spectroscopy (fNIRS) is a silent, non-invasive neuroimaging technique that is potentially well suited to auditory research. However, the reliability of auditory-evoked activation measured using fNIRS is largely unknown. The present study investigated the test-retest reliability of speech-evoked fNIRS responses in normally-hearing adults. Seventeen participants underwent fNIRS imaging in two sessions separated by three months. In a block design, participants were presented with auditory speech, visual speech (silent speechreading), and audiovisual speech conditions. Optode arrays were placed bilaterally over the temporal lobes, targeting auditory brain regions. A range of established metrics was used to quantify the reproducibility of cortical activation patterns, as well as the amplitude and time course of the haemodynamic response within predefined regions of interest. The use of a signal processing algorithm designed to reduce the influence of systemic physiological signals was found to be crucial to achieving reliable detection of significant activation at the group level. For auditory speech (with or without visual cues), reliability was good to excellent at the group level, but highly variable among individuals. Temporal-lobe activation in response to visual speech was less reliable, especially in the right hemisphere. Consistent with previous reports, fNIRS reliability was improved by averaging across a small number of channels overlying a cortical region of interest. Overall, the present results confirm that fNIRS can measure speech-evoked auditory responses in adults that are highly reliable at the group level, and indicate that signal processing to reduce physiological noise may substantially improve the reliability of fNIRS measurements
- …