1,522 research outputs found
Raman Scattered He II 6545 Line in the Symbiotic Star V1016 Cygni
We present a spectrum of the symbiotic star V1016 Cyg observed with the 3.6 m
Canada-France-Hawaii Telescope, in order to illustrate a method to measure the
covering factor of the neutral scattering region around the giant component
with respect to the hot emission region around the white dwarf component. In
the spectrum, we find broad wings around H and a broad emission feature
around 6545 that is blended with the [N II] 6548 line.
These two features are proposed to be formed by Raman scattering by atomic
hydrogen, where the incident radiation is proposed to be UV continuum radiation
around Ly in the former case and He II 1025 emission line
arising from transitions for the latter feature. We remove the
H wings by a template Raman scattering wing profile and subtract the [N
II] 6548 line using the 3 times stronger [N II] 6583
feature in order to isolate the He II Raman scattered 6545 \AA line. We obtain
the flux ratio of the He II 6560 emission
line and the 6545 \AA feature for V1016 Cyg. Under the assumption that the He
II emission from this object is isotropic, this ratio is converted to the ratio
of the number of the incident photons and that
of the scattered photons. This implies that the scattering region with H I
column density covers 17 per cent of the
emission region. By combining the presumed binary period yrs of this
system we infer that a significant fraction of the slow stellar wind from the
Mira component is ionized and that the scattering region around the Mira
extends a few tens of AU, which is closely associated with the mass loss
process of the Mira component.Comment: 12 pages, 6 figures, accepted for publication in Ap
PHP152 How are topics selected and prioritized by the national institute of health and care excellence (nice) and what might be the options if a technology is not selected?
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Species-specific differences in the expression of the HNF1A, HNF1B and HNF4A genes
Background: The HNF1A, HNF1B and HNF4A genes are part of an autoregulatory network in mammalian pancreas, liver, kidney and gut. The layout of this network appears to be similar in rodents and humans, but inactivation of HNF1A, HNF1B or HNF4A genes in animal models cause divergent phenotypes to those seen in man. We hypothesised that some differences may arise from variation in the expression profile of alternatively processed isoforms between species. Methodology/Principal Findings: We measured the expression of the major isoforms of the HNF1A, HNF1B and HNF4A genes in human and rodent pancreas, islet, liver and kidney by isoform-specific quantitative real-time PCR and compared their expression by the comparative Ct (??Ct) method. We found major changes in the expression profiles of the HNF genes between humans and rodents. The principal difference lies in the expression of the HNF1A gene, which exists as three isoforms in man, but as a single isoform only in rodents. More subtle changes were to the balance of HNF1B and HNF4A isoforms between species; the repressor isoform HNF1B(C) comprised only 6% in human islets compared with 24–26% in rodents (p = 0.006) whereas HNF4A9 comprised 22% of HNF4A expression in human pancreas but only 11% in rodents (p = 0.001). Conclusions/Significance: The differences we note in the isoform-specific expression of the human and rodent HNF1A, HNF1B and HNF4A genes may impact on the absolute activity of these genes, and therefore on the activity of the pancreatic transcription factor network as a whole. We conclude that alterations to expression of HNF isoforms may underlie some of the phenotypic variation caused by mutations in these genes
A comparison of two-coloured filter systems for treating visual reading difficulties
Copyright @ 2013 Informa UK Ltd.Purpose: Visual disturbances that make it difficult to read text are often termed “visual stress”. Coloured filters in spectacles may help some children overcome reading problems that are often caused by visual stress. It has been suggested that for optimal effect each child requires an individually prescribed colour for each eye, as determined in systems such as the “Harris Foundation” coloured filters. Alternatively, it has been argued that only blue or yellow filters, as used in the “Dyslexia Research Trust” (DRT) filter system, are necessary to affect the underlying physiology. Method: A randomised, double blind trial with 73 delayed readers, was undertaken to compare changes in reading and spelling as well as irregular and non-word reading skills after 3 months of wearing either the Harris or the DRT filters. Results: Reading improved significantly after wearing either type of filter (t = −8.4, p < 0.01), with 40% of the children improving their reading age by 6 months or more during the 3 month trial. However, spelling ability (t = 2.1, p = 0.05) and non-word reading (f = 4.7, p < 0.05) improved significantly more with the DRT than with the Harris filters. Conclusion: Education and rehabilitation professionals should therefore, consider coloured filters as an effective intervention for delayed readers experiencing visual stress
PHP152 How are topics selected and prioritized by the national institute of health and care excellence (nice) and what might be the options if a technology is not selected?
The O-type eclipsing binary SZ Cam revisited
We analyse new spectra of the multiple system SZ Cam because previous studies
found different values of the primary radial velocity amplitude. The older
solutions of light curves also have different ratios of secondary to primary
luminosity as inferred from the observed equivalent widths of spectral lines.
We therefore reanalyse the light curves of the eclipsing pair. Only the light
curve derived by Wesselink has a solution that agrees with the observed
equivalent width ratio. The resulting parameters of the binary are discussed.
Masses of and M, and radii and
R are derived. We point out that radial velocities measured
with the CCF method can be misleading when the method is applied to multiple
systems with complex line blends. New radial velocities are also obtained for
the visual component ADS 2984 A (HD 25639).Comment: Astronomy and Astrophysics, accepte
A global framework for action to improve the primary care response to chronic non-communicable diseases: a solution to a neglected problem.
BACKGROUND: Although in developing countries the burden of morbidity and mortality due to infectious diseases has often overshadowed that due to chronic non-communicable diseases (NCDs), there is evidence now of a shift of attention to NCDs. DISCUSSION: Decreasing the chronic NCD burden requires a two-pronged approach: implementation of the multisectoral policies aimed at decreasing population-level risks for NCDs, and effective and affordable delivery of primary care interventions for patients with chronic NCDs. The primary care response to common NCDs is often unstructured and inadequate. We therefore propose a programmatic, standardized approach to the delivery of primary care interventions for patients with NCDs, with a focus on hypertension, diabetes mellitus, chronic airflow obstruction, and obesity. The benefits of this approach will extend to patients with related conditions, e.g. those with chronic kidney disease caused by hypertension or diabetes. This framework for a "public health approach" is informed by experience of scaling up interventions for chronic infectious diseases (tuberculosis and HIV). The lessons learned from progress in rolling out these interventions include the importance of gaining political commitment, developing a robust strategy, delivering standardised interventions, and ensuring rigorous monitoring and evaluation of progress towards defined targets. The goal of the framework is to reduce the burden of morbidity, disability and premature mortality related to NCDs through a primary care strategy which has three elements: 1) identify and address modifiable risk factors, 2) screen for common NCDs and 3) and diagnose, treat and follow-up patients with common NCDs using standard protocols. The proposed framework for NCDs borrows the same elements as those developed for tuberculosis control, comprising a goal, strategy and targets for NCD control, a package of interventions for quality care, key operations for national implementation of these interventions (political commitment, case-finding among people attending primary care services, standardised diagnostic and treatment protocols, regular drug supply, and systematic monitoring and evaluation), and indicators to measure progress towards increasing the impact of primary care interventions on chronic NCDs. The framework needs evaluation, then adaptation in different settings. SUMMARY: A framework for a programmatic "public health approach" has the potential to improve on the current unstructured approach to primary care of people with chronic NCDs. Research to establish the cost, value and feasibility of implementing the framework will pave the way for international support to extend the benefit of this approach to the millions of people worldwide with chronic NCDs
The clonal structure and dynamics of the human T cell response to an organic chemical hapten
Diphenylcyclopropenone (DPC) is an organic chemical hapten which induces allergic contact dermatitis, and is used in treatment of warts, melanoma and alopecia areata. This therapeutic setting therefore provided an opportunity to study T cell receptor (TCR) repertoire changes in response to hapten sensitization in humans. Repeated exposure to DPC induced highly dynamic transient expansions of a polyclonal diverse T cell population. The number of TCRs expanded early after sensitization varies between individuals, and predicts the magnitude of the allergic reaction. The expanded TCRs show preferential TCR V and J gene usage, and consist of clusters of TCRs with similar sequences, two characteristic features of antigen-driven responses. The expanded TCRs share subtle sequence motifs that can be captured using a Dynamic Bayesian Network. These observations suggest the response to DPC is mediated by a polyclonal population of T cells recognizing a small number of dominant antigens
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