2,441 research outputs found
Age and structure parameters of a remote M31 globular cluster B514 based on HST, 2MASS, GALEX and BATC observations
B514 is a remote M31 globular cluster which locating at a projected distance
of R_p~55 kpc. Deep observations with the Advanced Camera for Surveys (ACS) on
the Hubble Space Telescope (HST) are used to provide the accurate integrated
light and star counts of B514. By coupling analysis of the distribution of the
integrated light with star counts, we are able to reliably follow the profile
of the cluster out to ~40". Based on the combined profile, we study in detail
its surface brightness distribution in F606W and F814W filters, and determine
its structural parameters by fitting a single-mass isotropic King model. The
results showed that, the surface brightness distribution departs from the
best-fit King model for r>10". B514 is quite flatted in the inner region, and
has a larger half-light radius than majority of normal globular clusters of the
same luminosity. It is interesting that, in the M_V versus log R_h plane, B514
lies nearly on the threshold for ordinary globular clusters as defined by
Mackey & van den Bergh. In addition, B514 was observed as part of the
Beijing-Arizona-Taiwan-Connecticut (BATC) Multicolor Sky Survey, using 13
intermediate-band filters covering a wavelength range of 3000--8500 \AA. Based
on aperture photometry, we obtain its SEDs as defined by the 13 BATC filters.
We determine the cluster's age and mass by comparing its SEDs (from 2267 to
20000{\AA}, comprising photometric data in the near-ultraviolet of GALEX, 5
SDSS bands, 13 BATC intermediate-band, and 2MASS near-infrared JHKs} filters)
with theoretical stellar population synthesis models, resulting in age of
Gyr. This age confirms the previous suggestion that B514 is an old
GC in M31. B514 has a mass of , and is a
medium-mass globular cluster in M31.Comment: Accepted for Publication in AJ, 18 pages, 6 figures and 9 table
CFTR with a partially deleted R domain corrects the cystic fibrosis chloride transport defect in human airway epithelia in vitro and in mouse nasal mucosa in vivo
Old stellar population synthesis: New age and mass estimates for Mayall II = G1
Mayall II = G1 is one of the most luminous globular clusters (GCs) in M31.
Here, we determine its age and mass by comparing multicolor photometry with
theoretical stellar population synthesis models. Based on far- and
near-ultraviolet GALEX photometry, broad-band UBVRI, and infrared JHK_s 2MASS
data, we construct the most extensive spectral energy distribution of G1 to
date, spanning the wavelength range from 1538 to 20,000 A. A quantitative
comparison with a variety of simple stellar population (SSP) models yields a
mean age that is consistent with G1 being among the oldest building blocks of
M31 and having formed within ~1.7 Gyr after the Big Bang. Irrespective of the
SSP model or stellar initial mass function adopted, the resulting mass
estimates (of order ) indicate that G1 is one of the most massive
GCs in the Local Group. However, we speculate that the cluster's exceptionally
high mass suggests that it may not be a genuine GC. We also derive that G1 may
contain, on average, far-ultraviolet-bright,
hot, extreme horizontal-branch stars, depending on the SSP model adopted. On a
generic level, we demonstrate that extensive multi-passband photometry coupled
with SSP analysis enables one to obtain age estimates for old SSPs to a similar
accuracy as from integrated spectroscopy or resolved stellar photometry,
provided that some of the free parameters can be constrained independently.Comment: Accepted for Publication in RAA, 12 pages, 1 figure, 2 table
Using a system dynamics framework to assess disease risks of pig value chains in Vietnam
In Vietnam, there are more than 4 million households producing pigs and pork. This
accounts for 57% of quantity of meat consumed. One of the most critical constraints
to pig production is the presence of animal disease. Pig disease outbreaks are a regular
occurrence in various parts of the country, with the industry affected by diseases
such as foot and mouth disease, porcine reproductive and respiratory syndrome, classical
swine fever, porcine high fever disease, and swine influenza. In addition, food
safety issues related to pig diseases and pork-borne diseases have also increasingly become
more important concerns for consumers. Recent studies have shown significant
changes in consumption behaviour in response to disease outbreaks. For instance, at
least half of urban consumers stop consuming pork in times of pig disease epidemics
and/or shift consumption to other meat substitutes such as poultry or fish. Disease
risks thus have both public health and livelihoods impacts that are important to understand
for appropriate policy and practice response.
A proposed methodology for investigating disease risks uses a system dynamics analysis
framework. System dynamics models are particularly relevant in the study of livestock
systems, as they capture the diverse actors and feedbacks present in value chains
and their interface with disease risk and behaviour. A system dynamics model is developed
that will describe different scenarios of disease risks and the consequences of
different interventions to mitigate these risks.
Data from a sample of 1000 farmers and value chain actors including all actors in the
pig value chain in Vietnam was collected with support from an ACIAR-funded project
on Reducing Disease Risks and Improving Food Safety in Smallholder Pig Value
Chains in Vietnam. We propose to test the hypotheses that disease risk is affected by
type of production system, feeding system and types of feed uses, access to inputs
and services, and selected socio-demographic variables associated with farmers and
location
Market-based approaches to food safety and animal health interventions: Lessons from smallholder pig value chains in Vietnam
Food safety and animal health issues are increasingly important constraints to smallholder pig
production in Viet Nam. Recent studies have highlighted the significant prevalence of animal
disease and foodâborne pathogens inherent within the Vietnamese pig sector. These in turn have
important negative livelihoods effects on smallholder pig producers and other value chain actors,
as well as important public health impacts. An important research gap is in identifying exâante
appropriate marketâbased policy responses that take into account the tradeoffs between
improved animal health and food safety outcomes and their associated costs for different value
chain actors as a means of developing chainâlevel solutions for their control. In this paper, we
constructed a system dynamics model of the pig value chain that combines a detailed model of
herd production and marketing with modules on shortâ and longâterm investment in pig capacity,
and decisions by value chain actors to adopt different innovations. The model further highlights
the feedbacks between different actors in the chain to identify both the potential entry points for
upgrading food safety and animal health as well as potential areas of tension within the chain that
may undermine uptake. Model results demonstrate that interventions at nodal levels (e.g. only at
farm or slaughterhouse level) are less costâeffective and sustainable than those that jointly
enhance incentives for control across the value chain, as weak links downstream undermine the
ability of producers to sustain good health practices
Human Bocavirus in Infants, New Zealand
In 2005, a parvovirus, subsequently named human bocavirus (HBoV), was discovered in respiratory samples taken from infants and children hospitalized at Karolinksa University Hospital, Sweden, with lower respiratory tract infection. HBoV has since been identified in infants and children with respiratory illness in >17 countries, at frequencies ranging from 1.5% to >18.0%. This study reaffirms previous reports of finding HBoV in a subset of infants with bronchiolitis. It is also, to our knowledge, the first study of its kind in New Zealand infants, confirming wide distribution of HBoV. In the northern hemisphere, HBoV circulates primarily during the winter months, although it continues circulating until early summer, later than most other seasonal respiratory viruses. Therefore, this study may underestimate the percentage of New Zealand infants with bronchiolitis whose HBoV test results were positive because sample collection ceased in October (southern hemisphere spring) at the end of the bronchiolitis epidemic. The small number of HBoV-positive infants prevents conclusions concerning ethnicity, coinfection, and bronchiolitis severity
Purchasing Over The Counter (OTC) Medicinal Products Containing Codeine - Easy Access, Advertising, Misuse and Perceptions of Medicinal Risk.
PURPOSE: Codeine containing medicines can carry a number of health risks associated with the increase in reported misuse and dependence, however they are still readily available over the counter (OTC) in many countries. The aim of this novel study was to report on the results of a survey of customers purchasing OTC codeine containing medicinal products at pharmacies in Ireland, South Africa and England; exploring use, sources of knowledge and perception of risks. METHODS: The study design was an exploratory cross sectional survey. It involved a customer self-administered questionnaire at the point of purchase (n=1230). Relationships between categorical variables were analysed using Pearson chi-square for bivariate analysis. Continuous scale variables were analysed using one way analysis of variance. RESULTS: In Ireland 6% stated they purchased codeine containing products weekly, in South Africa 13% and in England 16%. In Ireland and England women are more likely to view codeine containing products as harmful. In England older adults are more likely to perceive codeine containing products as harmful. A higher proportion of customers in South Africa opposed restricting codeine containing products to prescription only when compared with people in Ireland and England. CONCLUSIONS: Codeine containing products are widely purchased and used in all three jurisdictions. Whilst the majority of customers appear to have some awareness and knowledge of risks, it does not materially impact on their purchasing behaviour with a substantial minority purchasing/using such products on a weekly basis. This regularity of purchase whilst indicative of the popularity of such products, may also be a potential indicator of misuse. Future research is needed in relation to cultural and gendered differences and targeted information giving and harm reduction initiatives for safe usage of these medicinal products
Surface roughness dependent osteoblast and fibroblast response on poly(l-lactide) films and electrospun membranes
Poly(l-lactide) electrospun mats with random and aligned fiber orientation and films have been produced with degrees of crystallinity ranging from 0 up to nearly 50%. The overall surface roughness is practically constant irrespective of the sampling areas (1 Ă 1 ”m to 20 Ă 20 ”m) for degrees of crystallinity below 30%, increasing for higher degrees of crystallinity for the larger sampling areas. Further, due to fiber confinement, surface roughness variations are smaller in electrospun mats. Samples with 50% of crystallinity show the lowest osteoblast and the highest fibroblast proliferation. Therefore, it is verified that higher roughness promotes lower osteoblast but higher fibroblast proliferation. The overall results indicate the relevant role of the sub-microenvironment variations associated to the microscale roughness in determining the different cell responses.Portuguese Foundation for Science and Technology (FCT); contract grant numbers: C/FIS/UI607/2011, PTDC/CTM-NAN/112574/2009, contract grant numbers: SFRH/BPD/63148/2009, SFRH/BPD/90870/2012, MateproâOptimizing Materials and Processes, Programa Operacional Regional do Norte, Quadro de ReferĂȘncia
EstratĂ©gico Nacionalâ (QREN), âFundo Europeu de Desenvolvimento Regionalâ (FEDER); contract grant number: NORTE-07â0124-FEDER-000037
- âŠ