11,604 research outputs found
The supermassive black hole in NGC4486a detected with SINFONI at the VLT
The near-infrared integral field spectrograph SINFONI at the ESO VLT opens a
new window for the study of central supermassive black holes. With a near-IR
spatial resolution similar to HST optical and the ability to penetrate dust it
provides the possibility to explore the low-mass end of the M-sigma relation
(sigma<120km/s) where so far very few black hole masses were measured with
stellar dynamics. With SINFONI we observed the central region of the
low-luminosity elliptical galaxy NGC4486a at a spatial resolution of ~0.1arcsec
in the K band. The stellar kinematics was measured with a maximum penalised
likelihood method considering the region around the CO absorption band heads.
We determined a black hole mass of M_BH=1.25^{+0.75}_{-0.79} x 10^7 M_sun (90%
C.L.) using the Schwarzschild orbit superposition method including the full
2-dimensional spatial information. This mass agrees with the predictions of the
M-sigma relation, strengthening its validity at the lower sigma end.Comment: 7 pages, 7 figures. Accepted by MNRA
Beta-blockers and inhibitors of the renin-angiotensin aldosterone system for chronic heart failure with preserved ejection fraction
Background:
Betaâblockers and inhibitors of the reninâangiotensin aldosterone system improve survival and reduce morbidity in people with heart failure with reduced left ventricular ejection fraction. There is uncertainty whether these treatments are beneficial for people with heart failure with preserved ejection fraction and a comprehensive review of the evidence is required.
Objectives:
To assess the effects of betaâblockers, angiotensin converting enzyme inhibitors, angiotensin receptor blockers, angiotensin receptor neprilysin inhibitors, and mineralocorticoid receptor antagonists in people with heart failure with preserved ejection fraction.
Search methods:
We searched CENTRAL, MEDLINE, Embase and two clinical trial registries on 25 July 2017 to identify eligible studies. Reference lists from primary studies and review articles were checked for additional studies. There were no language or date restrictions.
Selection criteria:
We included randomised controlled trials with a parallel group design enrolling adult participants with heart failure with preserved ejection fraction, defined by a left ventricular ejection fraction of greater than 40 percent.
Data collection and analysis:
Two review authors independently selected studies for inclusion and extracted data. The outcomes assessed included cardiovascular mortality, heart failure hospitalisation, hyperkalaemia, allâcause mortality and quality of life. Risk ratios (RR) and, where possible, hazard ratios (HR) were calculated for dichotomous outcomes. For continuous data, mean difference (MD) or standardised mean difference (SMD) were calculated. We contacted trialists where neccessary to obtain missing data.
Main results:
37 randomised controlled trials (207 reports) were included across all comparisons with a total of 18,311 participants.
Ten studies (3087 participants) investigating betaâblockers (BB) were included. A pooled analysis indicated a reduction in cardiovascular mortality (15% of participants in the intervention arm versus 19% in the control arm; RR 0.78; 95% confidence interval (CI) 0.62 to 0.99; number needed to treat to benefit (NNTB) 25; 1046 participants; 3 studies). However, the quality of evidence was low and no effect on cardiovascular mortality was observed when the analysis was limited to studies with a low risk of bias (RR 0.81; 95% CI 0.50 to 1.29; 643 participants; 1 study). There was no effect on allâcause mortality, heart failure hospitalisation or quality of life measures, however there is uncertainty about these effects given the limited evidence available.
12 studies (4408 participants) investigating mineralocorticoid receptor antagonists (MRA) were included with the quality of evidence assessed as moderate. MRA treatment reduced heart failure hospitalisation (11% of participants in the intervention arm versus 14% in the control arm; RR 0.82; 95% CI 0.69 to 0.98; NNTB 41; 3714 participants; 3 studies; moderateâquality evidence) however, little or no effect on allâcause and cardiovascular mortality and quality of life measures was observed. MRA treatment was associated with a greater risk of hyperkalaemia (16% of participants in the intervention group versus 8% in the control group; RR 2.11; 95% CI 1.77 to 2.51; 4291 participants; 6 studies; highâquality evidence).
Eight studies (2061 participants) investigating angiotensin converting enzyme inhibitors (ACEI) were included with the overall quality of evidence assessed as moderate. The evidence suggested that ACEI treatment likely has little or no effect on cardiovascular mortality, allâcause mortality, heart failure hospitalisation, or quality of life. Data for the effect of ACEI on hyperkalaemia were only available from one of the included studies.
Eight studies (8755 participants) investigating angiotensin receptor blockers (ARB) were included with the overall quality of evidence assessed as high. The evidence suggested that treatment with ARB has little or no effect on cardiovascular mortality, allâcause mortality, heart failure hospitalisation, or quality of life. ARB was associated with an increased risk of hyperkalaemia (0.9% of participants in the intervention group versus 0.5% in the control group; RR 1.88; 95% CI 1.07 to 3.33; 7148 participants; 2 studies; highâquality evidence).
We identified a single ongoing placeboâcontrolled study investigating the effect of angiotensin receptor neprilysin inhibitors (ARNI) in people with heart failure with preserved ejection fraction.
Authors' conclusions:
There is evidence that MRA treatment reduces heart failure hospitalisation in heart failure with preserverd ejection fraction, however the effects on mortality related outcomes and quality of life remain unclear. The available evidence for betaâblockers, ACEI, ARB and ARNI is limited and it remains uncertain whether these treatments have a role in the treatment of HFpEF in the absence of an alternative indication for their use. This comprehensive review highlights a persistent gap in the evidence that is currently being addressed through several large ongoing clinical trials
Gambling Harm as a Global Public Health Concern: A Mixed Method Investigation of Trends in Wales
Background: Recent research evidence has suggested that gambling is a public health concern. A number of studies report the association between gambling activity and increased instances of various other harms, including substance misuse and psychological disorders. In parallel to alcohol misuse, it is also becoming clear that gambling related harm is more of a continuum of harm, as opposed to traditionally accepted categorisations of gambling behavior: safe and responsible or âproblemâ and harmful. Previous effective treatment models for alcohol misuse have considered a public health approach to develop interventions. As such, the current research seeks to use a public health approach to both investigate the extent of gambling harm across Wales, and to identify upstream predictors of harm to inform future interventions. /
Method: A triangulation of data collection methods was utilized across Wales, UK. Two hundred and forty-eight participants completed a quantitative survey relating to gambling behavior and related harm, which included the Problem Severity Gambling Index, the Gambling Commission measure of frequency, The Gambling Motives Questionnaire and the Fast Alcohol Screening tool. Ninety-eight of these participants completed a qualitative subsection. Structured interviews were conducted with 20 individuals from 11 service providers. Semi-structured interviews were conducted for the five case studies of individuals who had previously sought help for gambling. The geographical density and distribution of Licensed Gambling Outlets was also mapped in local areas. /
Results: The findings provide further evidence of a continuum of gambling related harm. Twenty seven percent of survey participants demonstrate some indicators of risk of gambling harm. Social, cultural and environmental contexts play a role in initiation and maintenance of gambling behavior and the subsequent related harm. Accounts from individuals corroborated the quantitative findings. /
Conclusions: Findings from this Welsh sample are in line with and add support to the growing international research evidence that gambling harms are a universal issue that cross cultures. It is clear that action is needed by legislators at a policy level and that broadening the focus of intervention to a public health level is necessary to develop effective strategies for harm reduction
Tuning the interactions between electron spins in fullerene-based triad systems
A series of six fullerene-linker-fullerene triads have been prepared by the stepwise addition of the fullerene cages to bridging moieties thus allowing the systematic variation of fullerene cage (C60 or C70) and linker (oxalate or terephthalate) and enabling precise control over the inter-fullerene separation. The fullerene triads exhibit good solubility in common organic solvents, have linear geometries and are diastereomerically pure. Cyclic voltammetric measurements demonstrate the excellent electron accepting capacity of all triads, with up to 6 electrons taken up per molecule in the potential range between -2.3 and 0.2 V (vs. Fc+/Fc). No significant electronic interactions between fullerene cages are observed in the ground state indicating that the individual properties of each C60 or C70 cage are retained within the triads. The electron-electron interactions in the electrochemically generated dianions of these triads, with one electron per fullerene cage were studied by EPR spectroscopy. The nature of electron-electron coupling observed at 77 K can be described as an equilibrium between a doublet and triplet state biradical which depends on the interfullerene spacing. The shorter oxalate-bridged triads exhibit stronger spin-spin coupling with triplet character, while in the longer terephthalate-bridged triads the intramolecular spin-spin coupling is significantly reduced
Atmospheric extinction coefficients in the band for several major international observatories: Results from the BiSON telescopes, 1984 to 2016
Over 30 years of solar data have been acquired by the Birmingham Solar
Oscillations Network (BiSON), an international network of telescopes used to
study oscillations of the Sun. Five of the six BiSON telescopes are located at
major observatories. The observational sites are, in order of increasing
longitude: Mount Wilson (Hale) Observatory (MWO), California, USA; Las Campanas
Observatory (LCO), Chile; Observatorio del Teide, Iza\~{n}a, Tenerife, Canary
Islands; the South African Astronomical Observatory (SAAO), Sutherland, South
Africa; Carnarvon, Western Australia; and the Paul Wild Observatory, Narrabri,
New South Wales, Australia. The BiSON data may be used to measure atmospheric
extinction coefficients in the band (approximately 700-900 nm),
and presented here are the derived atmospheric extinction coefficients from
each site over the years 1984 to 2016.Comment: 15 pages, 10 figures, 4 tables. Accepted by Astronomical Journal:
2017 July 2
The supermassive black hole of Fornax A
The radio galaxy Fornax A (NGC 1316) is a prominent merger remnant in the
outskirts of the Fornax cluster. Its giant radio lobes suggest the presence of
a powerful AGN and thus a central supermassive black hole (SMBH). We present
high-resolution adaptive optics assisted integral-field data of Fornax A, taken
with SINFONI at the Very Large Telescope in the K band. We use axisymmetric
orbit models to determine the mass of the SMBH in the centre of Fornax A. The
three-dimensional nature of our data provides the possibility to directly test
the consistency of the data with axisymmetry by modelling each of the four
quadrants separately. According to our dynamical models, consistent SMBH masses
and dynamical Ks band mass-to-light ratios are obtained for all quadrants, with
=1.3x10^8 M_\odot (rms(M_BH)=0.4x10^8 Msun) and =0.68
(rms(M/L)=0.03), confirming the assumption of axisymmetry. For the folded and
averaged data we find M_BH=(1.5+0.75-0.8)x10^8 Msun and M/L=(0.65+0.075-0.05)
(3-sigma errors). Thus the black-hole mass of Fornax A is consistent within the
error with the Tremaine (2002) M-sigma relation, but is a factor ~4 smaller
than expected from its bulge mass and the Marconi&Hunt (2003) relation.Comment: 24 pages, 24 figures, submitted to MNRA
What's new in atopic eczema? An analysis of systematic reviews published in 2015. Part 2: prevention and treatment
This review forms part of a series of annual updates that summarize the evidence base for atopic eczema (AE), providing a succinct guide for clinicians and patients. It provides a summary of key findings from 26 systematic reviews that were published during 2015, and focuses on the treatment and prevention of AE. For systematic reviews on the epidemiology and methodological issues, see Part 1 of this update. Topical corticosteroid withdrawal syndrome, âsteroid addictionâ, has been evaluated in a highâquality systematic review, which helps better define this entity and the risk factors for it. A Cochrane Review has not demonstrated any association between topical corticosteroid use in pregnancy and adverse outcomes, although very large quantities of potent/very potent topical corticosteroids may be associated with reduced birth weight. House dust mite avoidance strategies do not appear to prevent AE. Exposure to probiotics prenatally and in early infancy may help prevent AE, but there is no evidence that maternal diet or supplementation has a preventative effect
KOI-3890: A high mass-ratio asteroseismic red-giantM-dwarf eclipsing binary undergoing heartbeat tidal interactions
KOI-3890 is a highly eccentric, 153-day period eclipsing, single-lined
spectroscopic binary system containing a red-giant star showing solar-like
oscillations alongside tidal interactions. The combination of transit
photometry, radial velocity observations, and asteroseismology have enabled the
detailed characterisation of both the red-giant primary and the M-dwarf
companion, along with the tidal interaction and the geometry of the system. The
stellar parameters of the red-giant primary are determined through the use of
asteroseismology and grid-based modelling to give a mass and radius of
and
respectively. When combined with
transit photometry the M-dwarf companion is found to have a mass and radius of
and
. Moreover, through
asteroseismology we constrain the age of the system through the red-giant
primary to be . This provides a constraint on
the age of the M-dwarf secondary, which is difficult to do for other M-dwarf
binary systems. In addition, the asteroseismic analysis yields an estimate of
the inclination angle of the rotation axis of the red-giant star of
degrees. The obliquity of the system\textemdash the
angle between the stellar rotation axis and the angle normal to the orbital
plane\textemdash is also derived to give degrees
showing that the system is consistent with alignment. We observe no radius
inflation in the M-dwarf companion when compared to current low-mass stellar
models.Comment: 11 pages, 5 figures, accepted for publication in MNRA
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