761 research outputs found
Class II (DR) antigenexpression on CD8+ lymphocyte subsets in acquired immune deficiency syndrome (AIDS)
B<i>rachypodium distachyon</i> exhibits compatible interactions with <i>Oculimacula </i>spp. and <i>Ramularia collo-cygni</i>, providing the first pathosystem model to study eyespot and ramularia leaf spot diseases
B<i>rachypodium distachyon</i> exhibits compatible interactions with <i>Oculimacula </i>spp. and <i>Ramularia collo-cygni</i>, providing the first pathosystem model to study eyespot and ramularia leaf spot diseases
Brachypodium distachyon (Bd) has established itself as an essential tool for comparative genomic studies in cereals and increasing attention is being paid to its potential as a model pathosystem. Eyespot and ramularia leaf spot (RLS) are important diseases of wheat, barley and other small-grain cereals for which very little is known about the mechanisms of host resistance despite urgent requirements for plant breeders to develop resistant varieties. This work aimed to test the compatibility of interaction of two Bd accessions with the cereal pathogens Oculimacula spp. and Ramularia collocygni, the causal agents of eyespot and RLS diseases, respectively. Results showed that both Bd accessions developed symptoms similar to those on the natural host for all pathogen species tested. Microscopy images demonstrated that R. collo-cygni produced secondary conidia and both Oculimacula spp. formed characteristic infection structures on successive tissue layers. Visual disease assessment revealed that quantitative differences in disease severity exist between the two Bd accessions. The results presented here provide the first evidence that Bd is compatible with the main causal agents of eyespot and RLS diseases, and suggest that future functional genetic studies can be undertaken to investigate the mechanisms of eyespot and RLS disease resistance using Bd
Jizz and the joy of pattern recognition:virtuosity, discipline and the agency of insight in UK naturalists’ arts of seeing
Approaches to visual skilling from anthropology and STS have tended to highlight the forces of discipline and control in understanding how shared visual accounts of the world are created in the face of potential differences brought about by multi-sensorial perception. Drawing upon a range of observational and interview material from an immersion in naturalist training and biological recording activities between 2003 and 2009, I focus upon jizz, a distinct form of gestalt perception much coveted by naturalist communities in the UK. Jizz is described as a tacit and embodied way of seeing that instantaneously reveals the identity of a species, relying upon but simultaneously suspending the arduous and meticulous study of an organism’s diagnostic characteristics. I explore the potential and limitations of jizz to allow for both visual precision and an enchanted and varied form of encounter with nature. In so doing, I explore how the specific characteristics of wild, intangible and irreverent virtuoso performance work closely together with disciplining taxonomic standards. As such, discipline and irreverence work together, are mutually enabling, and allow for an accommodation rather than a segregation of potential difference brought about by perceptual variety
Inference of population splits and mixtures from genome-wide allele frequency data
Many aspects of the historical relationships between populations in a species
are reflected in genetic data. Inferring these relationships from genetic data,
however, remains a challenging task. In this paper, we present a statistical
model for inferring the patterns of population splits and mixtures in multiple
populations. In this model, the sampled populations in a species are related to
their common ancestor through a graph of ancestral populations. Using
genome-wide allele frequency data and a Gaussian approximation to genetic
drift, we infer the structure of this graph. We applied this method to a set of
55 human populations and a set of 82 dog breeds and wild canids. In both
species, we show that a simple bifurcating tree does not fully describe the
data; in contrast, we infer many migration events. While some of the migration
events that we find have been detected previously, many have not. For example,
in the human data we infer that Cambodians trace approximately 16% of their
ancestry to a population ancestral to other extant East Asian populations. In
the dog data, we infer that both the boxer and basenji trace a considerable
fraction of their ancestry (9% and 25%, respectively) to wolves subsequent to
domestication, and that East Asian toy breeds (the Shih Tzu and the Pekingese)
result from admixture between modern toy breeds and "ancient" Asian breeds.
Software implementing the model described here, called TreeMix, is available at
http://treemix.googlecode.comComment: 28 pages, 6 figures in main text. Attached supplement is 22 pages, 15
figures. This is an updated version of the preprint available at
http://precedings.nature.com/documents/6956/version/
Climate Dynamics: A Network-Based Approach for the Analysis of Global Precipitation
Precipitation is one of the most important meteorological variables for defining the climate dynamics, but the spatial patterns of precipitation have not been fully investigated yet. The complex network theory, which provides a robust tool to investigate the statistical interdependence of many interacting elements, is used here to analyze the spatial dynamics of annual precipitation over seventy years (1941-2010). The precipitation network is built associating a node to a geographical region, which has a temporal distribution of precipitation, and identifying possible links among nodes through the correlation function. The precipitation network reveals significant spatial variability with barely connected regions, as Eastern China and Japan, and highly connected regions, such as the African Sahel, Eastern Australia and, to a lesser extent, Northern Europe. Sahel and Eastern Australia are remarkably dry regions, where low amounts of rainfall are uniformly distributed on continental scales and small-scale extreme events are rare. As a consequence, the precipitation gradient is low, making these regions well connected on a large spatial scale. On the contrary, the Asiatic South-East is often reached by extreme events such as monsoons, tropical cyclones and heat waves, which can all contribute to reduce the correlation to the short-range scale only. Some patterns emerging between mid-latitude and tropical regions suggest a possible impact of the propagation of planetary waves on precipitation at a global scale. Other links can be qualitatively associated to the atmospheric and oceanic circulation. To analyze the sensitivity of the network to the physical closeness of the nodes, short-term connections are broken. The African Sahel, Eastern Australia and Northern Europe regions again appear as the supernodes of the network, confirming furthermore their long-range connection structure. Almost all North-American and Asian nodes vanish, revealing that extreme events can enhance high precipitation gradients, leading to a systematic absence of long-range patterns
A governance model for integrated primary/ secondary care for the health-reforming first world: results of a systematic review
Internationally, key health care reform elements rely on improved integration of care between the primary and secondary sectors. The objective of this systematic review is to synthesise the existing published literature on elements of current integrated primary/secondary health care. These elements and how they have supported integrated healthcare governance are presented.A systematic review of peer-reviewed literature from PubMed, MEDLINE, CINAHL, the Cochrane Library, Informit Health Collection, the Primary Health Care Research and Information Service, the Canadian Health Services Research Foundation, European Foundation for Primary Care, European Forum for Primary Care, and Europa Sinapse was undertaken for the years 2006-2012. Relevant websites were also searched for grey literature. Papers were assessed by two assessors according to agreed inclusion criteria which were published in English, between 2006-2012, studies describing an integrated primary/secondary care model, and had reported outcomes in care quality, efficiency and/or satisfaction.Twenty-one studies met the inclusion criteria. All studies evaluated the process of integrated governance and service delivery structures, rather than the effectiveness of services. They included case reports and qualitative data analyses addressing policy change, business issues and issues of clinical integration. A thematic synthesis approach organising data according to themes identified ten elements needed for integrated primary/secondary health care governance across a regional setting including: joint planning; integrated information communication technology; change management; shared clinical priorities; incentives; population focus; measurement - using data as a quality improvement tool; continuing professional development supporting joint working; patient/community engagement; and, innovation.All examples of successful primary/secondary care integration reported in the literature have focused on a combination of some, if not all, of the ten elements described in this paper, and there appears to be agreement that multiple elements are required to ensure successful and sustained integration efforts. Whilst no one model fits all systems these elements provide a focus for setting up integration initiatives which need to be flexible for adapting to local conditions and settings
Evaluation of the current knowledge limitations in breast cancer research: a gap analysis
BACKGROUND
A gap analysis was conducted to determine which areas of breast cancer research, if targeted by researchers and funding bodies, could produce the greatest impact on patients.
METHODS
Fifty-six Breast Cancer Campaign grant holders and prominent UK breast cancer researchers participated in a gap analysis of current breast cancer research. Before, during and following the meeting, groups in seven key research areas participated in cycles of presentation, literature review and discussion. Summary papers were prepared by each group and collated into this position paper highlighting the research gaps, with recommendations for action.
RESULTS
Gaps were identified in all seven themes. General barriers to progress were lack of financial and practical resources, and poor collaboration between disciplines. Critical gaps in each theme included: (1) genetics (knowledge of genetic changes, their effects and interactions); (2) initiation of breast cancer (how developmental signalling pathways cause ductal elongation and branching at the cellular level and influence stem cell dynamics, and how their disruption initiates tumour formation); (3) progression of breast cancer (deciphering the intracellular and extracellular regulators of early progression, tumour growth, angiogenesis and metastasis); (4) therapies and targets (understanding who develops advanced disease); (5) disease markers (incorporating intelligent trial design into all studies to ensure new treatments are tested in patient groups stratified using biomarkers); (6) prevention (strategies to prevent oestrogen-receptor negative tumours and the long-term effects of chemoprevention for oestrogen-receptor positive tumours); (7) psychosocial aspects of cancer (the use of appropriate psychosocial interventions, and the personal impact of all stages of the disease among patients from a range of ethnic and demographic backgrounds).
CONCLUSION
Through recommendations to address these gaps with future research, the long-term benefits to patients will include: better estimation of risk in families with breast cancer and strategies to reduce risk; better prediction of drug response and patient prognosis; improved tailoring of treatments to patient subgroups and development of new therapeutic approaches; earlier initiation of treatment; more effective use of resources for screening populations; and an enhanced experience for people with or at risk of breast cancer and their families. The challenge to funding bodies and researchers in all disciplines is to focus on these gaps and to drive advances in knowledge into improvements in patient care
Metabolic profiling detects early effects of environmental and lifestyle exposure to cadmium in a human population
Background: The ‘exposome’ represents the accumulation of all environmental exposures across a lifetime. Topdown
strategies are required to assess something this comprehensive, and could transform our understanding of
how environmental factors affect human health. Metabolic profiling (metabonomics/metabolomics) defines an
individual’s metabolic phenotype, which is influenced by genotype, diet, lifestyle, health and xenobiotic exposure,
and could also reveal intermediate biomarkers for disease risk that reflect adaptive response to exposure. We
investigated changes in metabolism in volunteers living near a point source of environmental pollution: a closed
zinc smelter with associated elevated levels of environmental cadmium. Methods: High-resolution 1H NMR spectroscopy (metabonomics) was used to acquire urinary metabolic profiles
from 178 human volunteers. The spectral data were subjected to multivariate and univariate analysis to identify
metabolites that were correlated with lifestyle or biological factors. Urinary levels of 8-oxo-deoxyguanosine were
also measured, using mass spectrometry, as a marker of systemic oxidative stress. Results: Six urinary metabolites, either associated with mitochondrial metabolism (citrate, 3-hydroxyisovalerate, 4-
deoxy-erythronic acid) or one-carbon metabolism (dimethylglycine, creatinine, creatine), were associated with
cadmium exposure. In particular, citrate levels retained a significant correlation to urinary cadmium and smoking
status after controlling for age and sex. Oxidative stress (as determined by urinary 8-oxo-deoxyguanosine levels)
was elevated in individuals with high cadmium exposure, supporting the hypothesis that heavy metal
accumulation was causing mitochondrial dysfunction. Conclusions: This study shows evidence that an NMR-based metabolic profiling study in an uncontrolled human
population is capable of identifying intermediate biomarkers of response to toxicants at true environmental
concentrations, paving the way for exposome research.
Keywords: metabonomics, cadmium, environmental health, exposome, metabolomics, molecular epidemiolog
VIGOR, an annotation program for small viral genomes
<p>Abstract</p> <p>Background</p> <p>The decrease in cost for sequencing and improvement in technologies has made it easier and more common for the re-sequencing of large genomes as well as parallel sequencing of small genomes. It is possible to completely sequence a small genome within days and this increases the number of publicly available genomes. Among the types of genomes being rapidly sequenced are those of microbial and viral genomes responsible for infectious diseases. However, accurate gene prediction is a challenge that persists for decoding a newly sequenced genome. Therefore, accurate and efficient gene prediction programs are highly desired for rapid and cost effective surveillance of RNA viruses through full genome sequencing.</p> <p>Results</p> <p>We have developed VIGOR (Viral Genome ORF Reader), a web application tool for gene prediction in influenza virus, rotavirus, rhinovirus and coronavirus subtypes. VIGOR detects protein coding regions based on sequence similarity searches and can accurately detect genome specific features such as frame shifts, overlapping genes, embedded genes, and can predict mature peptides within the context of a single polypeptide open reading frame. Genotyping capability for influenza and rotavirus is built into the program. We compared VIGOR to previously described gene prediction programs, ZCURVE_V, GeneMarkS and FLAN. The specificity and sensitivity of VIGOR are greater than 99% for the RNA viral genomes tested.</p> <p>Conclusions</p> <p>VIGOR is a user friendly web-based genome annotation program for five different viral agents, influenza, rotavirus, rhinovirus, coronavirus and SARS coronavirus. This is the first gene prediction program for rotavirus and rhinovirus for public access. VIGOR is able to accurately predict protein coding genes for the above five viral types and has the capability to assign function to the predicted open reading frames and genotype influenza virus. The prediction software was designed for performing high throughput annotation and closure validation in a post-sequencing production pipeline.</p
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