1,992 research outputs found
Distances to Cepheid Open Clusters Via Optical and K-Band Imaging
We investigate the reddening and Main Sequence fitted distances to eleven
young, Galactic open clusters that contain Cepheids. Each cluster contains or
is associated with at least one Cepheid variable star. Reddening to the
clusters is estimated using the U-B:B-V colours of the OB stars and the
distance modulus to the cluster is estimated via B-V:V and V-K:V
colour-magnitude diagrams. By main-sequence fitting we proceed to calibrate the
Cepheid P-L relation and find M_V=-2.81xlogP-1.33 +/-0.32 and
M_K=-3.44xlogP-2.20 +/-0.29 and a distance modulus to the LMC of 18.55+/-0.32
in the V-band and 18.47+/-0.29 in the K-band giving an overall distance modulus
to the LMC of 18.51+/-0.3.
In the case of two important clusters we find that the U-B:B-V diagram in
these clusters is not well fitted by the standard Main Sequence line. In one
case, NGC7790, we find that the F stars show a UV excess which if caused by
metallicity would imply Fe/H ~ -1.5; this is anomalously low compared to what
is expected for young open clusters. In a second case, NGC6664, the U-B:B-V
diagram shows too red U-B colours for the F stars which in this case would
imply a higher than solar metallicity. If these effects are due to metallicity
then it would imply that the Cepheid PL(V) and PL(K) zeropoints depend on
metallicity according to delta(M)/delta(Fe/H) ~0.66 in the sense that lower
metallicity Cepheids are intrinsically fainter. Medium-high resolution
spectroscopy for the main-sequence F stars in these two clusters is needed to
determine if metallicity really is the cause or whether some other explanation
applies.Comment: Submitted to MNRAS. Due to large size of paper, please see
http://star-www.dur.ac.uk:80/~fhoyle/papers.html for a version with the
figures correctly inserte
Do continuum beliefs reduce schizophrenia stigma? Effects of a laboratory intervention on behavioral and self-reported stigma
Background and objectives
Correlational research shows that belief in a continuum of psychiatric problems predicts decreased public stigma. However, the correlational findings fail to inform the stigma reduction prospects of manipulating continuum beliefs. All extant experimental work has been executed online. This study examined effects of a laboratory-based continuum intervention on behavioral and self-report measures of psychiatric stigma. Methods
Sixty-nine undergraduates believed that they would meet a man with schizophrenia. They then read a bogus scientific article that attested to a categorical view of schizophrenia, a continuum view, or that merely described schizophrenia. Some participants then completed a task that required reflection on their differences from (categorical group) or similarities to (continuum group) the man with schizophrenia. Participants eventually moved to an adjacent room and sat in one of several seats that varied in their proximity to a seat ostensibly occupied by the man with schizophrenia.
Results The continuum intervention decreased self-reported social distance and the categorical intervention increased endorsement of damaging stereotypes. Seat selection was unaffected by our manipulation, but we obtained evidence of significant links to validated stigma measures.
Limitations Our sample was small, and our behavioral stigma measure could be modified to maximize variability in participants\u27 seat selection. Conclusions
The study offers modest support of the stigma reduction effect of continuum belief intervention. It offers new evidence of the pernicious consequences of interventions that inflate perceptions of the “otherness” of individuals with psychiatric problems. Finally, it shines new light on stigma-related behavior measurable in the laboratory
Compacted nanosilica-talic/calcium carbonate polyacrylate composites prepared using accelerated sedimentation
The effectiveness of centrifugation as the compacting method in preparing high filler composites has been investigated. Different size and shape of fillers were used to ensure efficient filler space filling. In situ polymerization of bisphenol-A ethoxy diacrylate after centrifugating produced biomimetic composites with 74–86 % filler content. The filler space was efficiently filled by using a combination of nano and microsize fillers, especially in the nanosilica-CaCO3 composite. The morphology of the composites indicates that the fillers were well dispersed and embedded in the polymer matrix. The etched surface of the nanosilica-talc composite reveals that the combination of talc and nanosilica formed a biomimetic composite that displayed an ordered brick-and-mortar nacre-like structure. The wide-angle X-ray diffraction patterns indicate the crystal structure of CaCO3 and talc were maintained in the composit
2dF QSO Redshift Survey
With approximately 6000 QSO redshifts,the 2dF QSO redshift survey is already
the biggest complete QSO survey. The aim for the survey is to have 25000 QSO
redshifts, providing an order of magnitude increase in QSO clustering
statistics. We first describe the observational parameters of the 2dF QSO
survey. We then describe several highlights of the survey so far, including new
estimates of the QSO luminosity function and its evolution. We also review the
current status of QSO clustering analyses from the 2dF data. Finally, we
discuss how the complete QSO survey will be able to constrain the value of
Omega_o by measuring the evolution of QSO clustering, place limits on the
cosmological constant via a direct geometrical test and determine the form of
the fluctuation power-spectrum out to the approximately 1000 Mpc scales only
previously probed by COBE.Comment: 6 pages; to be published in Clustering at High Redshift, Marseille,
June 1999, eds. A. Mazure, O. LeFevre, V. Lebru
The 2dF QSO Redshift Survey
We present preliminary results from the 2-degree Field (2dF) QSO Redshift
Survey currently under way at the Anglo-Australian Telescope. This survey aims
to determine the redshifts of >25000 QSOs over a redshift range of 0.3<z<3.0
with the primary goal of investigating large-scale structure in the Universe to
high redshift and at very large scales (~1000h-1Mpc).
We describe the photometric procedure used to select QSO candidates for
spectroscopic observation. We then describe results from our first 2dF
observations, which have so far measured the redshifts for over 1000 QSOs. We
already find a significant detection of clustering and have also found one
close pair of QSOs (separation 17'') which are gravitational lens candidates.
To keep up to date with the current progress of the survey see:
http://msowww.anu.edu.au/~rsmith/QSO_Survey/qso_surv.htmlComment: 5 pages Latex including 6 figures, To appear in the proceedings of
"Evolution of Large Scale Structure: From Recombination to Garching", held
August 199
Treatment of multidrug-resistant tuberculosis in a remote, conflict-affected area of the Democratic Republic of Congo.
The Democratic Republic of Congo is a high-burden country for multidrug-resistant tuberculosis. Médecins Sans Frontières has supported the Ministry of Health in the conflict-affected region of Shabunda since 1997. In 2006, three patients were diagnosed with drug-resistant TB (DR-TB) and had no options for further treatment. An innovative model was developed to treat these patients despite the remote setting. Key innovations were the devolving of responsibility for treatment to non-TB clinicians remotely supported by a TB specialist, use of simplified monitoring protocols, and a strong focus on addressing stigma to support adherence. Treatment was successfully completed after a median of 24 months. This pilot programme demonstrates that successful treatment for DR-TB is possible on a small scale in remote settings
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