5,214 research outputs found
Being a non-drinking student: an interpretative phenomenological analysis
Recent research suggests that safer student alcohol consumption might be assisted by understanding how social occasions are managed by non-drinkers. In-depth, semi-structured interviews with five 19-22 year old non-drinking English undergraduates were subjected to interpretative phenomenological analysis (IPA). We present five inter-linked themes: âliving with challenges to non drinkingâ; âseeing what goes on in drinking environmentsâ; âdealing with conversations about non-drinking (âmaking excuses vs. coming outâ)â; âknowing which
friends care about youâ; and âthe importance of withholding âlegroomâ for peer pressureâ. Participants felt under persistent peer scrutiny (as a form of peer pressure) and could feel alienated in drinking environments. Talking about non-drinking was characterised by whether to âcome outâ (as a non-drinker) or âfake itâ (e.g., âIâm on antibioticsâ). Loyal friendships were reported as particularly important in this context. The decision not to drink was experienced as providing a successful buffer to peer pressure for former drinkers. Our findings unsettle
traditional health promotion campaigns which advocate moderate drinking among students without always suggesting how it might be most successfully accomplished, and offer
tentative guidance on how non-drinking during specific social occasions might be managed more successfully. Findings are discussed in relation to extant literature and future research directions are suggested
The Larson-Tinsley Effect in the UV: Interacting vs. `Normal' Spiral Galaxies
We compare the UV-optical colors of a well-defined set of optically-selected
pre-merger interacting galaxy pairs with those of normal spirals. The shorter
wavelength colors show a larger dispersion for the interacting galaxies than
for the spirals. This result can best be explained by higher star formation
rates on average in the interacting galaxies, combined with higher extinctions
on average. This is consistent with earlier studies, that found that the star
formation in interacting galaxies tends to be more centrally concentrated than
in normal spirals, perhaps due to gas being driven into the center by the
interaction. As noted in earlier studies, there is a large variation from
galaxy to galaxy in the implied star formation rates of the interacting
galaxies, with some galaxies having enhanced rates but others being fairly
quiescent.Comment: To appear in the Astronomical Journal. 22 pages, 22 figure
Star Clusters in M31: V. Internal Dynamical Trends: Some Troublesome, Some Reassuring
We present internal velocity dispersions and precise radial velocities for
200 globular clusters (GCs) in M31 that are derived using new high-resolution
spectra from MMT/Hectochelle. Of these, 163 also have King model structural
parameters that allow us to estimate their mass-to-light ratios. This is, by
far, the largest such dataset available for any galaxy, including the Milky
Way. These data strongly confirm earlier suggestions that the optical and
near-infrared mass-to-light ratios of M31 GCs decline with increasing
metallicity. This behavior is the opposite of that predicted by stellar
population models for a standard initial mass function. We show that this
phenomenon does not appear to be caused by standard dynamical evolution. A
shallower mass function for metal-rich GCs (with dN/dM ~ M^-0.8 to M^-1.3 below
one solar mass) can explain the bulk of extant observations. We also observe a
consistent, monotonic correlation between mass-to-light ratio and cluster mass.
This correlation, in contrast to the correlation with metallicity, is
well-explained by the accepted model of dynamical evolution of GCs through mass
segregation and the preferential loss of low-mass stars, and these data are
among the best available to constrain this process.Comment: AJ in press. 11 pages, 7 figures (not including tables) in emulate
forma
Dust attenuation in disk-dominated galaxies: evidence for the 2175A dust feature
The attenuation of starlight by interstellar dust is investigated in a sample
of low redshift, disk-dominated star-forming galaxies using photometry from
GALEX and SDSS. By considering broadband colors as a function of galaxy
inclination we are able to confidently separate trends arising from increasing
dust opacity from possible differences in stellar populations, since stellar
populations do not correlate with inclination. All commonly employed dust
attenuation curves (such as the Calzetti curve for starbursts, or a power-law
curve) provide poor fits to the ultraviolet colors for moderately and highly
inclined galaxies. This conclusion rests on the fact that the average FUV-NUV
color varies little from face-on to edge-on galaxies, while other colors such
as NUV-u and u-r vary strongly with inclination. After considering a number of
model variations, we are led to speculate that the presence of the strong dust
extinction feature at 2175A seen in the Milky Way (MW) extinction curve is
responsible for the observed trends. Independent of our interpretation, these
results imply that the modeling of dust attenuation in the ultraviolet is
significantly more complicated than traditionally assumed. These results also
imply a very weak dependence of the FUV-NUV color on total FUV attenuation, and
we conclude from this that it is extremely difficult to use only the observed
UV spectral slope to infer the total UV dust attenuation, as is commonly done.
We propose several simple tests that might finally identify the grain
population responsible for the 2175A feature.Comment: 16 pages, 10 figures. ApJ accepte
Placental Malaria: From Infection to Malfunction
Malaria during pregnancy is a major factor in infant morbidity and mortality. In this issue of Cell Host and Microbe, Conroy et al. (2013) propose that C5a, a product of complement cascade activation, counteracts the placental vascular remodeling response induced by Plasmodium infection and contributes to fetal growth restriction
Linking haloes to galaxies: how many halo properties are needed?
Recent studies emphasize that an empirical relation between the stellar mass
of galaxies and the mass of their host dark matter subhaloes can predict the
clustering of galaxies and its evolution with cosmic time. In this paper we
study the assumptions made by this methodology using a semi-analytical model
(SAM). To this end, we randomly swap between the locations of model galaxies
within a narrow range of subhalo mass (M_infall). We find that shuffled samples
of galaxies have different auto-correlation functions in comparison with the
original model galaxies. This difference is significant even if central and
satellite galaxies are allowed to follow a different relation between M_infall
and stellar mass, and can reach a factor of 2 for massive galaxies at redshift
zero. We analyze three features within SAMs that contribute to this effect: a)
The relation between stellar mass and subhalo mass evolves with redshift for
central galaxies, affecting satellite galaxies at the time of infall. b) The
stellar mass of galaxies falling into groups and clusters at high redshift is
different from the mass of central galaxies at the same time. c) The stellar
mass growth for satellite galaxies after infall can be significant and depends
on the infall redshift and the group mass. We show that the above is true for
differing SAMs, and that the effect is sensitive to the treatment of dynamical
friction and stripping of gas in satellite galaxies. We find that by using the
FoF group mass at redshift zero in addition to M_infall, an empirical model is
able to accurately reproduce the clustering properties of galaxies. On the
other hand, using the infall redshift as a second parameter does not yield as
good results because it is less correlated with stellar mass. Our analysis
indicates that environmental processes are important for modeling the
clustering and abundance of galaxies. (Abridged)Comment: Accepted for publication in MNRAS, minor changes from version
The SAVI Report: Sexual Abuse and Violence in Ireland. Executive Summary
The SAVI Report: Sexual Abuse and Violence in Ireland. Executive Summar
Systematic variation of the stellar Initial Mass Function with velocity dispersion in early-type galaxies
An essential component of galaxy formation theory is the stellar initial mass
function (IMF), that describes the parent distribution of stellar mass in star
forming regions. We present observational evidence in a sample of early-type
galaxies (ETGs) of a tight correlation between central velocity dispersion and
the strength of several absorption features sensitive to the presence of
low-mass stars. Our sample comprises ~40,000 ETGs from the SPIDER survey
(z<0.1). The data, extracted from the Sloan Digital Sky Survey, are combined,
rejecting both noisy data, and spectra with contamination from telluric lines,
resulting in a set of 18 stacked spectra at high signal-to-noise ratio (S/N>
400 per A). A combined analysis of IMF-sensitive line strengths and spectral
fitting is performed with the latest state-of the art population synthesis
models (an extended version of the MILES models). A significant trend is found
between IMF slope and velocity dispersion, towards an excess of low-mass stars
in the most massive galaxies. Although we emphasize that accurate values of the
IMF slope will require a detailed analysis of chemical composition (such as
[a/Fe] or even individual element abundance ratios), the observed trends
suggest that low-mass ETGs are better fit by a Kroupa-like IMF, whereas massive
galaxies require bottom-heavy IMFs, exceeding the Salpeter slope at velocity
dispersions above 200km/s.Comment: 5 pages, 4 figures, accepted for publication in MNRAS Letter
Increase in observed mental health difficulties one year after acute coronary syndrome: general practitioner survey.
BACKGROUND: General practitioners (GPs) are often the first to assess mental health difficulties after acute coronary syndrome (ACS). AIMS: To determine whether GPs observed an increase in mental health difficulties one-year post-hospitalisation for ACS. METHODS: Postal survey. RESULTS: GPs rated patients (n = 442) as having probable (GP assessed 10%) or definite (formally assessed 7%) mental health difficulties pre-hospitalisation. Post-hospitalisation the prevalence of probable cases increased significantly to 19% (OR = 4.3, 95% CI 2.1-10.2, P \u3c 0.001). In multivariate analysis, only smoking at index hospitalisation was associated with being assessed as a new case of probable/formal mental health difficulties (RR = 2.1, 95% CI 1.3-3.4, P = 0.003). Forty-seven percent of cases were prescribed some medication for this problem. CONCLUSIONS: GPs recorded a significant increase in mental health difficulties in ACS patients 12 months after hospitalisation, with smoking used as an indicator of new cases
Gender differences in the presentation and management of acute coronary syndromes: a national sample of 1365 admissions
Background Gender differences in presentation and management of acute coronary syndromes (ACS) are well established internationally. This study investigated differences in a national Irish sample. Design Cross-sectional survey. Methods All centres (n= 39) admitting cardiac patients to intensive/coronary care provided information on 25 consecutive acute myocardial infarction patients and other ACS patients admitted concurrently (n= 1365 episodes). Patient data was analyzed in terms of those with prior ACS/revascularization, and those without. Results Men with prior established ACS/revascularization were twice as likely to have received revascularization procedures (coronary artery bypass graft or percutaneous coronary intervention) prior to admission when controlling for age, total cholesterol and insurance status [odds ratio (OR) 1.97, 95% confidence interval (CI) 1.18â3.29, P = 0.011]. No gender differences were seen in acute-phase reperfusion (OR 0.96, 95% CI 0.76â1.24, P \u3e0.05) or antiplatelet therapy (OR 0.99, 95% CI 0.69â1.41, P \u3e 0.05). For patients with prior ACS/revascularization, men were twice as likely to receive statins on discharge after adjustment for age and total cholesterol (OR 1.94, 95% CI 1.02â3.71, P= 0.045). Conclusions Women were treated differently to men. Fewer women with a positive history of ACS received revascularization prior to current admission and fewer women were prescribed lipid-lowering medications on discharge. Acute phase hospital treatment was not gender determined. These findings have implications for secondary prevention in Ireland
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