334 research outputs found
Childhood IQ and marriage by mid-life: the Scottish Mental Survey 1932 and the Midspan Studies
The study examined the influence of IQ at age 11 years on marital status by mid-adulthood. The combined databases of the Scottish Mental Survey 1932 and the Midspan studies provided data from 883 subjects. With regard to IQ at age 11, there was an interaction between sex and marital status by mid-adulthood (p = 0.0001). Women who had ever-married achieved mean lower childhood IQ scores than women who had never-married (p < 0.001). Conversely, there was a trend for men who had ever-married to achieve higher childhood IQ scores than men who had never-married (p = 0.07). In men, the odds ratio of ever marrying was 1.35 (95% CI 0.98–1.86; p = 0.07) for each standard deviation increase in childhood IQ. Among women, the odds ratio of ever marrying by mid-life was 0.42 (95% CI 0.27–0.64; p = 0.0001) for each standard deviation increase in childhood IQ. Mid-life social class had a similar association with marriage, with women in more professional jobs and men in more manual jobs being less likely to have ever-married by mid-life. Adjustment for the effects of mid-life social class and height on the association between childhood IQ and later marriage, and vice versa, attenuated the effects somewhat, but suggested that IQ, height and social class acted partly independently
X-Ray Spectroscopy of Stars
(abridged) Non-degenerate stars of essentially all spectral classes are soft
X-ray sources. Low-mass stars on the cooler part of the main sequence and their
pre-main sequence predecessors define the dominant stellar population in the
galaxy by number. Their X-ray spectra are reminiscent, in the broadest sense,
of X-ray spectra from the solar corona. X-ray emission from cool stars is
indeed ascribed to magnetically trapped hot gas analogous to the solar coronal
plasma. Coronal structure, its thermal stratification and geometric extent can
be interpreted based on various spectral diagnostics. New features have been
identified in pre-main sequence stars; some of these may be related to
accretion shocks on the stellar surface, fluorescence on circumstellar disks
due to X-ray irradiation, or shock heating in stellar outflows. Massive, hot
stars clearly dominate the interaction with the galactic interstellar medium:
they are the main sources of ionizing radiation, mechanical energy and chemical
enrichment in galaxies. High-energy emission permits to probe some of the most
important processes at work in these stars, and put constraints on their most
peculiar feature: the stellar wind. Here, we review recent advances in our
understanding of cool and hot stars through the study of X-ray spectra, in
particular high-resolution spectra now available from XMM-Newton and Chandra.
We address issues related to coronal structure, flares, the composition of
coronal plasma, X-ray production in accretion streams and outflows, X-rays from
single OB-type stars, massive binaries, magnetic hot objects and evolved WR
stars.Comment: accepted for Astron. Astrophys. Rev., 98 journal pages, 30 figures
(partly multiple); some corrections made after proof stag
New Insights into White-Light Flare Emission from Radiative-Hydrodynamic Modeling of a Chromospheric Condensation
(abridged) The heating mechanism at high densities during M dwarf flares is
poorly understood. Spectra of M dwarf flares in the optical and
near-ultraviolet wavelength regimes have revealed three continuum components
during the impulsive phase: 1) an energetically dominant blackbody component
with a color temperature of T 10,000 K in the blue-optical, 2) a smaller
amount of Balmer continuum emission in the near-ultraviolet at lambda 3646
Angstroms and 3) an apparent pseudo-continuum of blended high-order Balmer
lines. These properties are not reproduced by models that employ a typical
"solar-type" flare heating level in nonthermal electrons, and therefore our
understanding of these spectra is limited to a phenomenological interpretation.
We present a new 1D radiative-hydrodynamic model of an M dwarf flare from
precipitating nonthermal electrons with a large energy flux of erg
cm s. The simulation produces bright continuum emission from a
dense, hot chromospheric condensation. For the first time, the observed color
temperature and Balmer jump ratio are produced self-consistently in a
radiative-hydrodynamic flare model. We find that a T 10,000 K
blackbody-like continuum component and a small Balmer jump ratio result from
optically thick Balmer and Paschen recombination radiation, and thus the
properties of the flux spectrum are caused by blue light escaping over a larger
physical depth range compared to red and near-ultraviolet light. To model the
near-ultraviolet pseudo-continuum previously attributed to overlapping Balmer
lines, we include the extra Balmer continuum opacity from Landau-Zener
transitions that result from merged, high order energy levels of hydrogen in a
dense, partially ionized atmosphere. This reveals a new diagnostic of ambient
charge density in the densest regions of the atmosphere that are heated during
dMe and solar flares.Comment: 50 pages, 2 tables, 13 figures. Accepted for publication in the Solar
Physics Topical Issue, "Solar and Stellar Flares". Version 2 (June 22, 2015):
updated to include comments by Guest Editor. The final publication is
available at Springer via http://dx.doi.org/10.1007/s11207-015-0708-
Risk of acute kidney injury and survival in patients treated with Metformin:an observational cohort study
Background: Whether metformin precipitates lactic acidosis in patients with chronic kidney disease (CKD) remains
under debate. We examined whether metformin use was associated with an increased risk of acute kidney injury
(AKI) as a proxy for lactic acidosis and whether survival among those with AKI varied by metformin exposure.
Methods: All individuals with type 2 diabetes and available prescribing data between 2004 and 2013 in Tayside,
Scotland were included. The electronic health record for diabetes which includes issued prescriptions was linked to
laboratory biochemistry, hospital admission, death register and Scottish Renal Registry data. AKI events were defined
using the Kidney Disease Improving Global Outcomes criteria with a rise in serum creatinine of at least 26.5 μmol/l or
a rise of greater than 150% from baseline for all hospital admissions. Cox Regression Analyses were used to examine
whether person-time periods in which current metformin exposure occurred were associated with an increased rate of
first AKI compared to unexposed periods. Cox regression was also used to compare 28 day survival rates following first
AKI events in those exposed to metformin versus those not exposed.
Results: Twenty-five thousand one-hundred fourty-eight patients were included with a total person-time of
126,904 person years. 4944 (19.7%) people had at least one episode of AKI during the study period. There
were 32.4 cases of first AKI/1000pyrs in current metformin exposed person-time periods compared to 44.9
cases/1000pyrs in unexposed periods. After adjustment for age, sex, diabetes duration, calendar time, number
of diabetes drugs and baseline renal function, current metformin use was not associated with AKI incidence,
HR 0.94 (95% CI 0.87, 1.02, p = 0.15). Among those with incident AKI, being on metformin at admission was
associated with a higher rate of survival at 28 days (HR 0.81, 95% CI 0.69, 0.94, p = 0.006) even after
adjustment for age, sex, pre-admission eGFR, HbA1c and diabetes duration.
Conclusions: Contrary to common perceptions, we found no evidence that metformin increases incidence of
AKI and was associated with higher 28 day survival following incident AKI
Determination Of Electron Flux Spectra In A Solar Flare With An Augmented Regularization Method: Application To Rhessi Data
Kontar et al. (2004) have shown how to recover mean source electron spectra
in solar flares through a physical constraint regularization analysis of the
bremsstrahlung photon spectra that they produce. They emphasize the use of
non-square inversion techniques, and preconditioning combined with physical
properties of the spectra to achieve the most meaningful solution to the
problem. Higher-order regularization techniques may be used to generate
forms with certain desirable properties (e.g., higher order
derivatives). They further note that such analyses may be used to infer
properties of the electron energy spectra at energies well above the maximum
photon energy observed. In this paper we apply these techniques to data from a
solar flare observed by RHESSI on 26 February, 2002. Results using different
orders of regularization are presented and compared for various time intervals.
Clear evidence is presented for a change in the value of the high-energy cutoff
in the mean source electron spectrum with time. We also show how the
construction of the injected (accelerated) electron spectrum
(assuming that Coulomb collisions in a cold target dominate the electron
energetics) is facilitated by the use of higher-order regularization methods.Comment: 10 pages, 7 figures, accepted to Solar Physic
Public and professional stakeholders’ perceptions of alcohol advertising and availability policies: a qualitative study
IntroductionReducing alcohol availability and restricting alcohol advertising are effective ways to reduce harm from alcohol. Implementation of public health policies involves collaboration between different stakeholders, and is influenced by public opinion. This paper explores public and professional stakeholders' perceptions of alcohol advertising and availability policies. It is the first to capture consensus and divergence in narratives of these stakeholders.MethodsWe conducted semi-structured interviews with 14 stakeholders from third sector organisations, government, public health and alcohol licensing in Scotland. We conducted 11 online focus groups with 45 participants, living in neighbourhoods in Scotland characterised by varying levels of urbanity, deprivation and retail density change. We gave participants a list of policies and discussed their views on acceptability, feasibility and likely success.ResultsDespite general consensus that regulation of alcohol advertising is an important priority, public stakeholders were concerned about the feasibility of advertising interventions and potential unintended consequences. While professional stakeholders were in favour of regulating alcohol availability, public stakeholders had misgivings about feasibility and effectiveness. When prompted to discuss specific interventions, similar views about protecting children and achieving cultural change emerged.Discussion and ConclusionsThis study highlights the importance of policy makers and other stakeholders to consider public stakeholders' opinions on alcohol policy and understanding that their views may be influenced by competing framings of alcohol problems. Attempts to increase support for alcohol control policies need to consider people's concerns about the effectiveness and potential unintended consequences of these policies, and the wider social context of alcohol consumption
The accessibility and acceptability of self-management support interventions for men with long term conditions: a systematic review and meta-synthesis of qualitative studies
Background: Self-management support interventions can improve health outcomes, but their impact is limited by the numbers of people able or willing to access them. Men’s attendance at existing self-management support services appears suboptimal despite their increased risk of developing many of the most serious long term conditions. The aim of this review was to determine whether current self-management support interventions are acceptable and accessible to men with long term conditions, and explore what may act as facilitators and barriers to access of interventions and support activities.
Methods: A systematic search for qualitative research was undertaken on CINAHL, EMBASE, MEDLINE, PsycINFO and Social Science Citation Index, in July 2013. Reference lists of relevant articles were also examined. Studies that used a qualitative design to explore men’s experiences of, or perceptions towards, self-management support for one or more long term condition were included. Studies which focused on experiences of living with a long term condition without consideration of self-management support were excluded. Thirty-eight studies met the inclusion criteria. A meta-ethnography approach was employed to synthesise the findings.
Results: Four constructs associated with men’s experience of, and perceptions towards, self management support were identified: 1) need for purpose; 2) trusted environments; 3) value of peers; and 4) becoming an expert. The synthesis showed that men may feel less comfortable participating in self-management support if it is viewed as incongruous with valued aspects of their identity, particularly when activities are perceived to challenge masculine ideals associated with independence, stoicism, and control. Men may find self-management support more attractive when it is perceived as action-oriented, having a clear purpose, and offering personally meaningful information and practical strategies that can be integrated into daily life.
Conclusions: Self-management support is most likely to be successful in engaging men when it is congruent with key aspects of their masculine identity. In order to overcome barriers to access and fully engage with interventions, some men may need self-management support interventions to be delivered in an environment that offers a sense of shared understanding, connectedness, and normality, and involves and/or is facilitated by men with a shared illness experience
Generalized Regularization Techniques With Constraints For The Analysis Of Solar Bremsstrahlung X-Ray Spectra
Hard X-ray spectra in solar flares provide knowledge of the electron spectrum
that results from acceleration and propagation in the solar atmosphere.
However, the inference of the electron spectra from solar X-ray spectra is an
ill-posed inverse problem. Here we develop and apply an enhanced regularization
algorithm for this process making use of physical constraints on the form of
the electron spectrum. The algorithm incorporates various features not
heretofore employed in the solar flare context: Generalized Singular Value
Decomposition (GSVD) to deal with different orders of constraints; rectangular
form of the cross-section matrix to extend the solution energy range;
regularization with various forms of the smoothing operator; and
"preconditioning" of the problem. We show by simulations that this technique
yields electron spectra with considerably more information and higher quality
than previous algorithms.Comment: 21 pages, 8 fugures, accepted to Solar Physic
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