243 research outputs found
Selenomethionine supplementation reduces lesion burden, improves vessel function and modulates the inflammatory response within the setting of atherosclerosis
Another cluster of red supergiants close to RSGC1
Recent studies have revealed massive star clusters in a region of the Milky
Way close to the tip of the Long Bar. These clusters are heavily obscured and
are characterised by a population of red supergiants. We analyse a previously
unreported concentration of bright red stars ~16' away from the cluster RSGC1.
We utilised near IR photometry to identify candidate red supergiants and then
K-band spectroscopy of a sample to characterise their properties.
We find a compact clump of eight red supergiants and five other candidates at
some distance, one of which is spectroscopically confirmed as a red supergiant.
These objects must form an open cluster, which we name Alicante 8. Because of
the high reddening and strong field contamination, the cluster sequence is not
clearly seen in 2MASS or UKIDSS near-IR photometry. From the analysis of the
red supergiants, we infer an extinction and an age close
to 20 Myr. Though this cluster is smaller than the three known previously, its
properties still suggest a mass in excess of 10 000 M_{\sun}. Its discovery
corroborates the hypothesis that star formation in this region has happened on
a wide scale between ~10 and ~20 Myr ago.Comment: Accepted for publication in Astronomy & Astrophysics. Figure 1
degraded and changed to B&W, Figure 2 degraded to meet size requirement
Radio and IR study of the massive star-forming region IRAS 16353-4636
Context. With the latest infrared surveys, the number of massive protostellar
candidates has increased significantly. New studies have posed additional
questions on important issues about the formation, evolution, and other
phenomena related to them. Complementary to infrared data, radio observations
are a good tool to study the nature of these objects, and to diagnose the
formation stage. Aims. Here we study the far-infrared source IRAS 16353-4636
with the aim of understanding its nature and origin. In particular, we search
for young stellar objects (YSOs), possible outflow structure, and the presence
of non-thermal emission. Methods. Using high-resolution, multi-wavelength radio
continuum data obtained with the Australia Telescope Compact Array, we image
IRAS 16353-4636 and its environment from 1.4 to 19.6 GHz, and derive the
distribution of the spectral index at maximum angular resolution. We also
present new JHKs photometry and spectroscopy data obtained at ESO NTT. 13 CO
and archival HI line data, and infrared databases (MSX, GLIMPSE, MIPSGal) are
also inspected. Results. The radio continuum emission associated with IRAS
16353-4636 was found to be extended (~10 arcsec), with a bow-shaped morphology
above 4.8 GHz, and a strong peak persistent at all frequencies. The NIR
photometry led us to identify ten near-IR sources and classify them according
to their color. We used the HI line data to derive the source distance, and
analyzed the kinematical information from the CO and NIR lines detected.
Conclusions. We have identified the source IRAS 16353-4636 as a new
protostellar cluster. In this cluster we recognized three distinct sources: a
low-mass YSO, a high-mass YSOs, and a mildly confined region of intense and
non-thermal radio emission. We propose the latter corresponds to the terminal
part of an outflow.Comment: To appear in A&A. 10 pages, 8 figure
The Metabochip, a Custom Genotyping Array for Genetic Studies of Metabolic, Cardiovascular, and Anthropometric Traits
PMCID: PMC3410907This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Concordance of randomised controlled trials for artificial intelligence interventions with the CONSORT-AI reporting guidelines
The Consolidated Standards of Reporting Trials extension for Artificial Intelligence interventions (CONSORT-AI) was published in September 2020. Since its publication, several randomised controlled trials (RCTs) of AI interventions have been published but their completeness and transparency of reporting is unknown. This systematic review assesses the completeness of reporting of AI RCTs following publication of CONSORT-AI and provides a comprehensive summary of RCTs published in recent years. 65 RCTs were identified, mostly conducted in China (37%) and USA (18%). Median concordance with CONSORT-AI reporting was 90% (IQR 77–94%), although only 10 RCTs explicitly reported its use. Several items were consistently under-reported, including algorithm version, accessibility of the AI intervention or code, and references to a study protocol. Only 3 of 52 included journals explicitly endorsed or mandated CONSORT-AI. Despite a generally high concordance amongst recent AI RCTs, some AI-specific considerations remain systematically poorly reported. Further encouragement of CONSORT-AI adoption by journals and funders may enable more complete adoption of the full CONSORT-AI guidelines
Atmospheric abundance and global emissions of perfluorocarbons CF4, C2F6 and C3F8 since 1800 inferred from ice core, firn, air archive and in situ measurements
Perfluorocarbons (PFCs) are very potent and long-lived greenhouse gases in the atmosphere, released predominantly during aluminium production and semiconductor manufacture. They have been targeted for emission controls under the United Nations Framework Convention on Climate Change. Here we present the first continuous records of the atmospheric abundance of CF4 (PFC-14), C2F6 (PFC-116) and C3F8 (PFC-218) from 1800 to 2014. The records are derived from high-precision measurements of PFCs in air extracted from polar firn or ice at six sites (DE08, DE08-2, DSSW20K, EDML, NEEM and South Pole) and air archive tanks and atmospheric air sampled from both hemispheres. We take account of the age characteristics of the firn and ice core air samples and demonstrate excellent consistency between the ice core, firn and atmospheric measurements. We present an inversion for global emissions from 1900 to 2014. We also formulate the inversion to directly infer emission factors for PFC emissions due to aluminium production prior to the 1980s. We show that 19th century atmospheric levels, before significant anthropogenic influence, were stable at 34.1 ± 0.3 ppt for CF4 and below detection limits of 0.002 and 0.01 ppt for C2F6 and C3F8, respectively. We find a significant peak in CF4 and C2F6 emissions around 1940, most likely due to the high demand for aluminium during World War II, for example for construction of aircraft, but these emissions were nevertheless much lower than in recent years. The PFC emission factors for aluminium production in the early 20th century were significantly higher than today but have decreased since then due to improvements and better control of the smelting process. Mitigation efforts have led to decreases in emissions from peaks in 1980 (CF4) or early-to-mid-2000s (C2F6 and C3F8) despite the continued increase in global aluminium production; however, these decreases in emissions appear to have recently halted. We see a temporary reduction of around 15 % in CF4 emissions in 2009, presumably associated with the impact of the global financial crisis on aluminium and semiconductor production
Searching for hidden Wolf-Rayet stars in the Galactic Plane - 15 new Wolf-Rayet stars
We report the discovery of fifteen previously unknown Wolf-Rayet (WR) stars
found as part of an infrared broad-band study of candidate WR stars in the
Galaxy. We have derived an empirically-based selection algorithm which has
selected ~5000 WR candidate stars located within the Galactic Plane drawn from
the GLIMPSE (mid-infrared) and 2MASS (near-infrared) catalogues. Spectroscopic
follow-up of 184 of these reveals eleven WN and four WC-type WR stars. Early WC
subtypes are absent from our sample and none show evidence for circumstellar
dust emission. Of the candidates which are not WR stars, ~120 displayed
hydrogen emission line features in their spectra. Spectral features suggest
that the majority of these are in fact B supergiants/hypergiants, ~40 of these
are identified Be/B[e] candidates.
Here, we present the optical spectra for six of the newly-detected WR stars,
and the near-infrared spectra for the remaining nine of our sample. With a WR
yield rate of ~7% and a massive star detection rate of ~65%, initial results
suggest that this method is one of the most successful means for locating
evolved, massive stars in the Galaxy.Comment: Accepted for publication in MNRAS. Figures degraded in quality, full
version available by anonymous ftp (ftp:astro1.shef.ac.uk,
/pub/lh/hadfield.ps.gz
Recommended from our members
Erratum: Sequence data and association statistics from 12,940 type 2 diabetes cases and controls.
This corrects the article DOI: 10.1038/sdata.2017.179
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