12,208 research outputs found
Cardiovascular disease and air pollution in Scotland: no association or insufficient data and study design?
<p><b>Background:</b>
Coronary heart disease and stroke are leading causes of mortality and ill health in Scotland, and clear associations have been found in previous studies between air pollution and cardiovascular disease. This study aimed to use routinely available data to examine whether there is any evidence of an association between short-term exposure to particulate matter (measured as PM10, particles less than 10 micrograms per cubic metre) and hospital admissions due to cardiovascular disease, in the two largest cities in Scotland during the years 2000 to 2006.</p>
<p><b>Methods:</b> The study utilised an ecological time series design, and the analysis was based on overdispersed Poisson log-linear models.</p>
<p><b>Results:</b> No consistent associations were found between PM10 concentrations and cardiovascular hospital admissions in either of the cities studied, as all of the estimated relative risks were close to one, and all but one of the associated 95% confidence intervals contained the null risk of one.</p>
<p><b>Conclusions:</b> This study suggests that in small cities, where air quality is relatively good, then either PM10 concentrations have no effect on cardiovascular ill health, or that the routinely available data and the corresponding study design are not sufficient to detect an association.</p>
Long slit spectroscopy of NH2 in comets Halley, Wilson, and Nishikawa-Takamizawa-Tago
Long-slit spectra of comets Halley, Wilson and Nishikawa-Takamizawa-Tago were obtained with the 3.9 meter Anglo-Australian Telescope. Spectra of comets Halley and Wilson were obtained with the IPCS at a spectral resolution of 0.5 A and a spatial resolution of 10(exp 3) km. Spectra of comets Wilson and Nishikawa-Takamizawa-Tago were obtained with a CCD at a spectral resolution of 1.5 A and a spatial resolution of approximately 3 x 10(exp 3) km. Surface brightness profiles for NH2 were extracted from the long-slit spectra of each comet. The observed surface brightness profiles extend along the slit to approximately 6 x 10(exp 4) km from the nucleus in both sunward and tailward directions. By comparing surface distribution calculated from an appropriate coma model with observed surface brightness distributions, the photodissociation timescale of the parent molecule of NH2 can be inferred. The observed NH2 surface brightness profiles in all three comets compares well with a surface brightness profile calculated using the vectorial model, an NH3 photodissociation timescale of 7 x 10(exp 3) seconds, and an NH2 photodissociation timescale of 34,000 seconds
RAT0455+1305: another pulsating hybrid sdB star
RAT0455+1305 was discovered during the Rapid Temporal Survey which aims in
finding any variability on timescales of a few minutes to several hours. The
star was found to be another sdBV star with one high amplitude mode and
relatively long period. These features along with estimation of T_eff and log g
makes this star very similar to Balloon 090100001. Encouraged by prominent
results obtained for the latter star we have decided to perform white light
photometry on RAT0455+1305. In 2009 we used the 1.5m telescope located in San
Pedro Martir Observatory in Mexico. Fourier analysis confirmed the dominant
mode found in the discovery data, uncovered another peak close to the dominant
one, and three peaks in the low frequency region. This shows that RAT0455+1305
is another hybrid sdBV star pulsating in both p- and g-modes.Comment: Proceedings of The Fourth Meeting on Hot Subdwarf Stars and Related
Objects held in China, 20-24 July 2009. Accepted for publication in
Astrophysics & Space Scienc
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