825 research outputs found
The Balmer decrement of SDSS galaxies
High resolution spectra are necessary to distinguish and correctly measure
the Balmer emission lines due to the presence of strong metal and Balmer
absorption features in the stellar continuum. This accurate measurement is
necessary for use in emission line diagnostics, such as the Balmer decrement
(i.e. Halpha/Hbeta), used to determine the attenuation of galaxies. Yet at high
redshifts obtaining such spectra becomes costly. Balmer emission line
equivalent widths are much easier to measure, requiring only low resolution
spectra or even simple narrow band filters and therefore shorter observation
times. However a correction for the stellar continuum is still needed for this
equivalent width Balmer decrement. We present here a statistical analysis of
the Sloan Digital Sky Survey Data Release 7 emission line galaxy sample, using
the spectrally determined Balmer emission line fluxes and equivalent widths.
Using the large numbers of galaxies available in the SDSS catalogue, we
determined an equivalent width Balmer decrement including a statistically-based
correction for the stellar continuum. Based on this formula, the attenuation of
galaxies can now be obtained from low spectral resolution observations. In
addition, this investigation also revealed an error in the Hbeta line fluxes,
within the SDSS DR7 MPA/JHU catalogue, with the equivalent widths
underestimated by average ~0.35A in the emission line galaxy sample. This error
means that Balmer decrement determined attenuations are overestimated by a
systematic 0.1 magnitudes in A_V, and future analyses of this sample need to
include this correction.Comment: 10 pages, accepted MNRA
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Health care deprivation profiles in the measurement of inequality and inequity: an application to GP fundholding in the English NHS
This paper proposes a new approach to the measurement of inequality and inequity in the delivery of health care based on contributions from the literature on poverty and deprivation. This approach has some appealing characteristics: (1) inequity is additively decomposable by population subgroups; (2) the approach does not rely on socio-economic ranks; (3) it provides a graphical representation of the distribution of inequity; (4) it offers a range of indices consistent with dominance. An empirical application is provided investigating the effect of the GP fundholding reform on equity in English NHS. The results show that the most equitable GP practices self-selected into the scheme in 1991; evidence of an inequity-reducing treatment effect as well as a self-selection effect are found in 1992 and 1993; the self-selection process reduces and no evidence of a treatment effect is present thereafter
First lattice QCD estimate of the g_{D^* D pi} coupling
We present the results of the first lattice QCD study of the strong coupling
g_{D^* D pi}. From our simulations in the quenched approximation, we obtain
g_{D^* D pi} = 18.8 +/- 2.3^{+1.1}_{-2.0} and hat(g)_c = 0.67 +/-
0.08^{+0.04}_{-0.06}. Whereas previous theoretical studies gave different
predictions, our result favours a large value for hat(g)_c. It agrees very well
with the recent experimental value by CLEO. hat(g) varies very little with the
heavy mass and we find in the infinite mass limit hat(g)_infinity = 0.69(18).Comment: 24 pages, 7 figures; references added, corrected typos, Comments
added about the continuum limi
Effect of Silicon dioxide coating of acrylic resin surfaces on Candida albicans adhesion.
Acrylic resin has been used in the manufacture of prostheses, however, in the oral cavity, this material starts to retain microorganisms capable of causing gingival inflammation due its porosities. The aim of this study was to evaluate the influence of the use of silicon dioxide as a coating layer applied onto acrylic resin, on the adhesion of Candida albicans (Ca). After the incubation period in Sabouraud Dextrose Broth, a total of 1 ml of the Ca suspension was added to plate wells, each well containing a specimen of acrylic resin. The adhesion ability of Ca on acrylic resin was determined by counting colonies. Three groups (n = 6) of acrylic resin were assessed: with polishing (RP); without polishing (RW); with polishing and coating layer of silicon dioxide (RPC). Ca deposited on the surface of the acrylic resin was also observed using Scanning Electron Microscopy (SEM). Statistical assessment by Kruskal-Wallis and Student-Newman-Keuls Method were done (α = 2%). There was significant difference among the groups. The RPC group showed the lowest growth, with an average of 5.59 Log CFU/cm 2 ; there was a statistically significant difference in relation to group RW, which presented a growth of 6.07 Log CFU/cm 2 and to group RP with 5.91 Log CFU/cm 2 (p < 000.1). SEM images demonstrated that in the RP and RPC group, the surface of the resin had greater regularity, and smaller number of microorganisms. The application of silicon dioxide coating on acrylic resin appears to be a promising alternative, and its use can help in reducing the adhesion of Ca in prostheses
Tissue-specific regulation of mouse MicroRNA genes in endoderm-derived tissues
MicroRNAs fine-tune the activity of hundreds of protein-coding genes. The identification of tissue-specific microRNAs and their promoters has been constrained by the limited sensitivity of prior microRNA quantification methods. Here, we determine the entire microRNAome of three endoderm-derived tissues, liver, jejunum and pancreas, using ultra-high throughput sequencing. Although many microRNA genes are expressed at comparable levels, 162 microRNAs exhibited striking tissue-specificity. After mapping the putative promoters for these microRNA genes using H3K4me3 histone occupancy, we analyzed the regulatory modules of 63 microRNAs differentially expressed between liver and jejunum or pancreas. We determined that the same transcriptional regulatory mechanisms govern tissue-specific gene expression of both mRNA and microRNA encoding genes in mammals
Covariant Light-Front Approach for s-wave and p-wave Mesons: Its Application to Decay Constants and Form Factors
We study the decay constants and form factors of the ground-state s-wave and
low-lying p-wave mesons within a covariant light-front approach. Numerical
results of the form factors for transitions between a heavy pseudoscalar meson
and an s-wave or p-wave meson and their momentum dependence are presented in
detail. In particular, form factors for heavy-to-light and B to D**
transitions, where D** denotes generically a p-wave charmed meson, are compared
with other model calculations. The experimental measurements of the decays B^-
to D** pi^- and B to D D**_s are employed to test the decay constants of D**_s
and the B to D** transition form factors. The heavy quark limit behavior of the
decay constants and form factors is examined and it is found that the
requirement of heavy quark symmetry is satisfied. The universal Isgur-Wise (IW)
functions, one for s-wave to s-wave and two for s-wave to p-wave transitions,
are obtained. The values of IW functions at zero recoil and their slope
parameters can be used to test the Bjorken and Uraltsev sum rules.Comment: 59 pages, 6 figures. Version to appear in Phys. Rev. D. Changes are:
(i) D_s to phi transition form factors are discussed and compared with the
recent FOCUS measurements and (ii) zero mode effects are clarifie
The organisation and delivery of health improvement in general practice and primary care: a scoping study
Background
This project examines the organisation and delivery of health improvement activities by and within general practice and the primary health-care team. The project was designed to examine who delivers these interventions, where they are located, what approaches are developed in practices, how individual practices and the primary health-care team organise such public health activities, and how these contribute to health improvement. Our focus was on health promotion and ill-health prevention activities.
Aims
The aim of this scoping exercise was to identify the current extent of knowledge about the health improvement activities in general practice and the wider primary health-care team. The key objectives were to provide an overview of the range and type of health improvement activities, identify gaps in knowledge and areas for further empirical research. Our specific research objectives were to map the range and type of health improvement activity undertaken by general practice staff and the primary health-care team based within general practice; to scope the literature on health improvement in general practice or undertaken by health-care staff based in general practice and identify gaps in the evidence base; to synthesise the literature and identify effective approaches to the delivery and organisation of health improvement interventions in a general practice setting; and to identify the priority areas for research as defined by those working in general practice.
Methods
We undertook a comprehensive search of the literature. We followed a staged selection process involving reviews of titles and abstracts. This resulted in the identification of 1140 papers for data extraction, with 658 of these papers selected for inclusion in the review, of which 347 were included in the evidence synthesis. We also undertook 45 individual and two group interviews with primary health-care staff.
Findings
Many of the research studies reviewed had some details about the type, process or location, or who provided the intervention. Generally, however, little attention is paid in the literature to examining the impact of the organisational context on the way services are delivered or how this affects the effectiveness of health improvement interventions in general practice. We found that the focus of attention is mainly on individual prevention approaches, with practices engaging in both primary and secondary prevention. The range of activities suggests that general practitioners do not take a population approach but focus on individual patients. However, it is clear that many general practitioners see health promotion as an integral part of practice, whether as individual approaches to primary or secondary health improvement or as a practice-based approach to improving the health of their patients. Our key conclusion is that there is currently insufficient good evidence to support many of the health improvement interventions undertaken in general practice and primary care more widely.
Future Research
Future research on health improvement in general practice and by the primary health-care team needs to move beyond clinical research to include delivery systems and be conducted in a primary care setting. More research needs to examine areas where there are chronic disease burdens – cancer, dementia and other disabilities of old age. Reviews should be commissioned that examine the whole prevention pathway for health problems that are managed within primary care drawing together research from general practice, pharmacy, community engagement, etc
Timing of host feeding drives rhythms in parasite replication
Circadian rhythms enable organisms to synchronise the processes underpinning survival and reproduction to anticipate daily changes in the external environment. Recent work shows that daily (circadian) rhythms also enable parasites to maximise fitness in the context of ecological interactions with their hosts. Because parasite rhythms matter for their fitness, understanding how they are regulated could lead to innovative ways to reduce the severity and spread of diseases. Here, we examine how host circadian rhythms influence rhythms in the asexual replication of malaria parasites. Asexual replication is responsible for the severity of malaria and fuels transmission of the disease, yet, how parasite rhythms are driven remains a mystery. We perturbed feeding rhythms of hosts by 12 hours (i.e. diurnal feeding in nocturnal mice) to desynchronise the hosts' peripheral oscillators from the central, light-entrained oscillator in the brain and their rhythmic outputs. We demonstrate that the rhythms of rodent malaria parasites in day-fed hosts become inverted relative to the rhythms of parasites in night-fed hosts. Our results reveal that the hosts' peripheral rhythms (associated with the timing of feeding and metabolism), but not rhythms driven by the central, light-entrained circadian oscillator in the brain, determine the timing (phase) of parasite rhythms. Further investigation reveals that parasite rhythms correlate closely with blood glucose rhythms. In addition, we show that parasite rhythms resynchronise to the altered host feeding rhythms when food availability is shifted, which is not mediated through rhythms in the host immune system. Our observations suggest that parasites actively control their developmental rhythms. Finally, counter to expectation, the severity of disease symptoms expressed by hosts was not affected by desynchronisation of their central and peripheral rhythms. Our study at the intersection of disease ecology and chronobiology opens up a new arena for studying host-parasite-vector coevolution and has broad implications for applied bioscience
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Measuring change in health care equity using small-area administrative data - evidence from the English NHS 2001-2008
This study developed a method for measuring change in socio-economic equity in health care utilisation using small-area level administrative data. Our method provides more detailed information on utilisation than survey data but only examines socio-economic differences between neighbourhoods rather than individuals. The context was the English NHS from 2001 to 2008, a period of accelerated expenditure growth and pro-competition reform. Hospital records for all adults receiving non-emergency hospital care in the English NHS from 2001 to 2008 were aggregated to 32,482 English small areas with mean population about 1500 and combined with other small-area administrative data. Regression models of utilisation were used to examine year-on-year change in the small-area association between deprivation and utilisation, allowing for population size, age-sex composition and disease prevalence including (from 2003 to 2008) cancer, chronic kidney disease, coronary heart disease, diabetes, epilepsy, hypertension, hypothyroidism, stroke, transient ischaemic attack and (from 2006 to 2008) atrial fibrillation, chronic obstructive pulmonary disease, obesity and heart failure. There was no substantial change in small-area associations between deprivation and utilisation for outpatient visits, hip replacement, senile cataract, gastroscopy or coronary revascularisation, though overall non-emergency inpatient admissions rose slightly faster in more deprived areas than elsewhere. Associations between deprivation and disease prevalence changed little during the period, indicating that observed need did not grow faster in more deprived areas than elsewhere. We conclude that there was no substantial deterioration in socio-economic equity in health care utilisation in the English NHS from 2001 to 2008, and if anything, there may have been a slight improvement
Multi-criteria correlation of tephra deposits to source centres applied in the Auckland Volcanic Field, New Zealand
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