782 research outputs found
Application of Framingham risk estimates to ethnic minorities in United Kingdom and implications for primary prevention of heart disease in general practice : cross sectional population based study
Objective To compare the 10 year risk of coronary
heart disease (CHD), stroke, and combined
cardiovascular disease (CVD) estimated from the
Framingham equations.
Design Population based cross sectional survey.
Setting Nine general practices in south London.
Population 1386 men and women, age 40Â59 years,
with no history of CVD (475 white people, 447 south
Asian people, and 464 people of African origin), and
a subgroup of 1069 without known diabetes, left
ventricular hypertrophy, peripheral vascular disease,
renal impairment, or target organ damage.
Main outcome measures 10 year risk estimates.
Results People of African origin had the lowest 10
year risk estimate of CHD adjusted for age and sex
(7.0%, 95% confidence interval 6.5 to 7.5) compared
with white people (8.8%, 8.2 to 9.5) and south Asians
(9.2%, 8.6 to 9.9) and the highest estimated risk of
stroke (1.7% (1.5 to 1.9), 1.4% (1.3 to 1.6), 1.6% (1.5 to
1.8), respectively). The estimate risk of combined
CVD, however, was highest in south Asians (12.5%,
11.6 to 13.4) compared with white people (11.9%,
11.0 to 12.7) and people of African origin (10.5%, 9.7
to 11.2). In the subgroup of 1069, the probability that
a risk of CHD >15% would identify risk of combined
CVD >20% was 91% in white people and 81% in
both south Asians and people of African origin. The
use of thresholds for risk of CHD of 12% in south
Asians and 10% in people of African origin would
increase the probability of identifying those at risk to
100% and 97%, respectively.
Conclusion Primary care doctors should use a lower
threshold of CHD risk when treating mild
uncomplicated hypertension in people of African or
south Asian origin
POD-Based reduced order methods for optimal control problems governed by parametric partial differential equation with varying boundary control
In this work we propose tailored model order reduction for varying boundary optimal con-trol problems governed by parametric partial differential equations. With varying boundary control, we mean that a specific parameter changes where the boundary control acts on the system. This peculiar formulation might benefit from model order reduction. Indeed, fast and reliable simulations of this model can be of utmost usefulness in many applied fields, such as geophysics and energy engineering. However, varying boundary control features very complicated and diversified parametric behaviour for the state and adjoint variables. The state solution, for example, changing the boundary control parameter, might feature transport phenomena. Moreover, the problem loses its affine structure. It is well known that classical model order reduction techniques fail in this setting, both in accuracy and in efficiency. Thus, we propose reduced approaches inspired by the ones used when dealing with wave-like phenomena. Indeed, we compare standard proper orthogonal decomposi-tion with two tailored strategies: geometric recasting and local proper orthogonal decom-position. Geometric recasting solves the optimization system in a reference domain simpli-fying the problem at hand avoiding hyper-reduction, while local proper orthogonal decom-position builds local bases to increase the accuracy of the reduced solution in very general settings (where geometric recasting is unfeasible). We compare the various approaches on two different numerical experiments based on geometries of increasing complexity.& COPY; 2023 Elsevier Inc. All rights reserved
Population dietary salt reduction and the risk of cardiovascular disease. A scientific statement from the European Salt Action Network
Abstract The publication in the last few years of a number of prospective observational studies suggesting a J-shaped association between levels of salt (sodium) consumption and cardiovascular outcomes has opened a debate on the pertinence of population-wide salt reduction policies to reduce cardiovascular disease burden, and some have even questioned the global World Health Organization guidelines, that recommend a 30% reduction in salt consumption by 2025, aiming at an ideal target of no more than 5 g of salt consumption per day. In September 2018 the European Salt Action Network (E.S.A.N.), after appraising the quality of publications questioning the appropriateness of population salt reduction, discussed the scientific evidence and identified the pitfalls of recent data. The new evidence was deemed inadequate and, in places, biased by flawed methodology. These were identified in the biased assessment of sodium intake from spot urine and the use of the Kawasaki formula, the biased assessment of the sodium–outcome relationships in prospective observational studies using spot urine samples, the impact of reverse causality in such studies, the inadequate analytical approaches to data analysis, the lack of biological plausibility and the lack of precision in assessing long-term salt consumption, as recently demonstrated in studies using more stringent quality features in their study designs. On the basis of such appraisal, the E.S.A.N. agreed a statement confirming the support to the implementation of national and regional programmes of moderate reduction in salt intake, as recommended by the World Health Organization
Cluster galaxies 10 billion years ago
Cl J1449+0856 is a spectroscopically confirmed galaxy cluster at z ~ 2. The detection of a faint, extended X-ray emission, suggestive of an already evolved, partially relaxed structure, puts this system among the most distant "established” clusters rather than in the realm of z≳2 proto-clusters. This gives us a chance of studying galaxies in an evolved overdense environment very close to their formation epoch, and in particular to trace the evolution of early-type galaxies in clusters back to ten billion years ag
Morphology of low-redshift compact galaxy clusters I. Shapes and radial profiles
The morphology of clusters of galaxies may be described with a set of
parameters which contain information about the formation and evolutionary
history of these systems. In this paper we present a preliminary study of the
morphological parameters of a sample of 28 compact Abell clusters extracted
from DPOSS data. The morphology of galaxy clusters is parameterized by their
apparent ellipticity, position angle of the major axis, centre coordinates,
core radius and beta-model power law index. Our procedure provides estimates of
these parameters by simultaneously fitting them all, overcoming some of the
difficulties induced by sparse data and low number statistics typical of this
kind of analysis. The cluster parameters were fitted in a 3 x 3 h^-2 sqMpc
region, measuring the background in a 2 <R< 2.5 h^-1Mpc annulus. We also
explore the correlations between shape and profile parameters and other cluster
properties. One third of this compact cluster sample has core radii smaller
than 50 h^-1 kpc, i.e. near the limit that our data allow us to resolve,
possibly consistent with cusped models. The remaining clusters span a broad
range of core radii up to 750 h^-1 kpc. More than 80 per cent of this sample
has ellipticity higher than 0.2. The alignment between the cluster and the
major axis of the dominant galaxy is confirmed, while no correlation is
observed with other bright cluster members. No significant correlation is found
between cluster richness and ellipticity. Instead, cluster richness is found to
correlate, albeit with large scatter, with the cluster core radius.[abridged]Comment: 23 pages, 17 figures, accepted for publication in MNRAS. Full paper
including full resolution figures 2 and 9 at
http://www.eso.org/~vstrazzu/P/ME1030fv.pd
Formation epochs, star formation histories and sizes of massive early-type galaxies in cluster and field environments at z=1.2: insights from the rest-frame UV
We derive stellar masses, ages and star formation histories of massive
early-type galaxies in the z=1.237 RDCS1252.9-2927 cluster and compare them
with those measured in a similarly mass-selected sample of field contemporaries
drawn from the GOODS South Field. Robust estimates of these parameters are
obtained by comparing a large grid of composite stellar population models with
8-9 band photometry in the rest-frame NUV, optical and IR, thus sampling the
entire relevant domain of emission of the different stellar populations.
Additionally, we present new, deep -band photometry of both fields, giving
access to the critical FUV rest-frame, in order to constrain empirically the
dependence on the environment of the most recent star formation processes. We
find that early-type galaxies, both in the cluster and in the field, show
analogous optical morphologies, follow comparable mass vs. size relation, have
congruent average surface stellar mass densities and lie on the same Kormendy
relation. We also that a fraction of early-type galaxies in the field employ
longer timescales, , to assemble their mass than their cluster
contemporaries. Hence we conclude that, while the formation epoch of early-type
only depends on their mass, the environment does regulate the timescales of
their star formation histories. Our deep -band imaging strongly supports
this conclusions. It shows that cluster galaxies are at least 0.5 mag fainter
than their field contemporaries of similar mass and optical-to-infrared colors,
implying that the last episode of star formation must have happened more
recently in the field than in the cluster.Comment: 20pages, 10 figures. to appear on Ap
The Red Sequence of High-Redshift Clusters: a Comparison with Cosmological Galaxy Formation Models
We compare the results from a semi-analytic model of galaxy formation with
spectro-photometric observations of distant galaxy clusters observed in the
range 0.8< z< 1.3. We investigate the properties of their red sequence (RS)
galaxies and compare them with those of the field at the same redshift. In our
model we find that i) a well-defined, narrow RS is obtained already by z= 1.2;
this is found to be more populated than the field RS, analogously to what
observed and predicted at z=0; ii) the predicted U-V rest-frame colors and
scatter of the cluster RS at z=1.2 have average values of 1 and 0.15
respectively, with a cluster-to-cluster variance of 0.2 and 0.06, respectively.
The scatter of the RS of cluster galaxies is around 5 times smaller than the
corresponding field value; iii) when the RS galaxies are considered, the mass
growth histories of field and cluster galaxies at z=1.2 are similar, with 90 %
of the stellar mass of RS galaxies at z=1.2 already formed at cosmic times
t=2.5 Gyr, and 50 % at t=1 Gyr; v) the predicted distribution of stellar ages
of RS galaxies at z=1.2 peaks at 3.7 Gyr for both cluster and field
populations; however, for the latter the distribution is significantly skewed
toward lower ages. When compared with observations, the above findings show an
overall consistency, although the average value 0.07 of the observed cluster RS
scatter (U-V colors) at z=1.2 is smaller than the corresponding model central
value. We discuss the physical origin and the significance of the above results
in the framework of cosmological galaxy formation.Comment: 14 pages, accepted for publication in ApJ. Updated one referenc
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