7 research outputs found
A far UV study of interstellar gas towards HD34078: high excitation H2 and small scale structure - Based on observations performed by the FUSE mission and at the CFHT telescope
To investigate the presence of small scale structure in the spatial
distribution of H2 molecules we have undertaken repeated FUSE UV observations
of the runaway O9.5V star, HD34078. In this paper we present five spectra
obtained between January 2000 and October 2002. These observations reveal an
unexpectedly large amount of highly excited H2. Column densities for H2 levels
from (v = 0, J = 0) up to (v = 0, J = 11) and for several v = 1 and v = 2
levels are determined. These results are interpreted in the frame of a model
involving essentially two components: i) a foreground cloud (unaffected by
HD34078) responsible for the H2 (J = 0, 1), CI, CH, CH+ and CO absorptions; ii)
a dense layer of gas (n = 10E4 cm-3) close to the O star and strongly
illuminated by its UV flux which accounts for the presence of highly excited
H2. Our model successfully reproduces the H2 excitation, the CI fine-structure
level populations as well as the CH, CH+ and CO column densities. We also
examine the time variability of H2 absorption lines tracing each of these two
components. From the stability of the J = 0, 1 and 2 damped H2 profiles we
infer a 3 sigma upper limit on column density variations Delta(N(H2))/N(H2) of
5% over scales ranging from 5 to 50 AU. This result clearly rules out any
pronounced ubiquitous small scale "density" structure of the kind apparently
seen in HI. The lines from highly excited gas are also quite stable (equivalent
to Delta(N)/N <= 30%) indicating i) that the ambient gas through which HD34078
is moving is relatively uniform and ii) that the gas flow along the shocked
layer is not subject to marked instabilitie
Illness causal beliefs in Turkish immigrants
<p>Abstract</p> <p>Background</p> <p>People hold a wide variety of beliefs concerning the causes of illness. Such beliefs vary across cultures and, among immigrants, may be influenced by many factors, including level of acculturation, gender, level of education, and experience of illness and treatment. This study examines illness causal beliefs in Turkish-immigrants in Australia.</p> <p>Methods</p> <p>Causal beliefs about somatic and mental illness were examined in a sample of 444 members of the Turkish population of Melbourne. The socio-demographic characteristics of the sample were broadly similar to those of the Melbourne Turkish community. Five issues were examined: the structure of causal beliefs; the relative frequency of natural, supernatural and metaphysical beliefs; ascription of somatic, mental, or both somatic and mental conditions to the various causes; the correlations of belief types with socio-demographic, modernizing and acculturation variables; and the relationship between causal beliefs and current illness.</p> <p>Results</p> <p>Principal components analysis revealed two broad factors, accounting for 58 percent of the variation in scores on illness belief scales, distinctly interpretable as natural and supernatural beliefs. Second, beliefs in natural causes were more frequent than beliefs in supernatural causes. Third, some causal beliefs were commonly linked to both somatic and mental conditions while others were regarded as more specific to either somatic or mental disorders. Last, there was a range of correlations between endorsement of belief types and factors defining heterogeneity within the community, including with demographic factors, indicators of modernizing and acculturative processes, and the current presence of illness.</p> <p>Conclusion</p> <p>Results supported the classification of causal beliefs proposed by Murdock, Wilson & Frederick, with a division into natural and supernatural causes. While belief in natural causes is more common, belief in supernatural causes persists despite modernizing and acculturative influences. Different types of causal beliefs are held in relation to somatic or mental illness, and a variety of apparently logically incompatible beliefs may be concurrently held. Illness causal beliefs are dynamic and are related to demographic, modernizing, and acculturative factors, and to the current presence of illness. Any assumption of uniformity of illness causal beliefs within a community, even one that is relatively culturally homogeneous, is likely to be misleading. A better understanding of the diversity, and determinants, of illness causal beliefs can be of value in improving our understanding of illness experience, the clinical process, and in developing more effective health services and population health strategies.</p