124 research outputs found
The evolution of health policy guidelines for assisted reproduction in the Republic of Ireland, 2004-2009
This analysis reports on Irish regulatory policies for in vitro fertilisation (IVF) from 2004-2009, in the context of membership changes within the Medical Council of Ireland. To achieve this, the current (2009) edition of the Guide to Professional Conduct & Ethics was compared with the immediately preceding version (2004). The statutory composition of the Medical Council from 2004-2009 was also studied. Content analysis of the two editions identified the following differences: 1) The 2004 guide states that IVF "should only be used after thorough investigation has failed to reveal a treatable cause of the infertility", while the 2009 guide indicates IVF "should only be used after thorough investigation has shown that no other treatment is likely to be effective"; 2) The 2004 stipulation stating that fertilized ovum (embryo) "must be used for normal implantation and must not be deliberately destroyed" is absent from the 2009 guidelines; 3) The option to donate "unused fertilised ova" (embryos) is omitted from the 2009 guidelines; 4) The 2009 guidelines state that ART should be offered only by "suitably qualified professionals, in appropriate facilities, and according to the international best practice"; 5) The 2009 guidelines introduce criteria that donations as part of a donor programme should be "altruistic and non-commercial". These last two points represent original regulatory efforts not appearing in the 2004 edition. The Medical Practitioners Act 2007 reduced the number of physicians on the Medical Council to 6 (of 25) members. The ethical guidelines from 2004 preceded this change, while the reconstituted Medical Council published the 2009 version. Between 2004 and 2009, substantial modifications in reproductive health policy were incorporated into the Medical Council's ethical guidelines. The absence of controlling Irish legislation means that patients and IVF providers in Ireland must rely upon these guidelines by default. Our critique traces the evolution of public policy on IVF during a time when the membership of the Medical Council changed radically; reduced physician contribution to decision-making was associated with diminished protection for IVF-derived embryos in Ireland. Considerable uncertainty on IVF practice in Ireland remains
Effect of hosts on competition among clones and evidence of differential selection between pathogenic and saprophytic phases in experimental populations of the wheat pathogen Phaeosphaeria nodorum
<p>Abstract</p> <p>Background</p> <p>Monoculture, multi-cropping and wider use of highly resistant cultivars have been proposed as mechanisms to explain the elevated rate of evolution of plant pathogens in agricultural ecosystems. We used a mark-release-recapture experiment with the wheat pathogen <it>Phaeosphaeria nodorum </it>to evaluate the impact of two of these mechanisms on the evolution of a pathogen population. Nine <it>P. nodorum </it>isolates marked with ten microsatellite markers and one minisatellite were released onto five replicated host populations to initiate epidemics of Stagonospora nodorum leaf blotch. The experiment was carried out over two consecutive host growing seasons and two pathogen collections were made during each season.</p> <p>Results</p> <p>A total of 637 pathogen isolates matching the marked inoculants were recovered from inoculated plots over two years. Genetic diversity in the host populations affected the evolution of the corresponding <it>P. nodorum </it>populations. In the cultivar mixture the relative frequencies of inoculants did not change over the course of the experiment and the pathogen exhibited a low variation in selection coefficients.</p> <p>Conclusions</p> <p>Our results support the hypothesis that increasing genetic heterogeneity in host populations may retard the rate of evolution in associated pathogen populations. Our experiment also provides indirect evidence of fitness costs associated with host specialization in <it>P. nodorum </it>as indicated by differential selection during the pathogenic and saprophytic phases.</p
Development and Validation of Risk Scores for All-Cause Mortality for a Smartphone-Based "General Health Score" App: Prospective Cohort Study Using the UK Biobank
This is the final version. Available on open access from JMIR Publications via the DOI in this recordBACKGROUND: Given the established links between an individual's behaviors and lifestyle factors and potentially adverse health outcomes, univariate or simple multivariate health metrics and scores have been developed to quantify general health at a given point in time and estimate risk of negative future outcomes. However, these health metrics may be challenging for widespread use and are unlikely to be successful at capturing the broader determinants of health in the general population. Hence, there is a need for a multidimensional yet widely employable and accessible way to obtain a comprehensive health metric. OBJECTIVE: The objective of the study was to develop and validate a novel, easily interpretable, points-based health score ("C-Score") derived from metrics measurable using smartphone components and iterations thereof that utilize statistical modeling and machine learning (ML) approaches. METHODS: A literature review was conducted to identify relevant predictor variables for inclusion in the first iteration of a points-based model. This was followed by a prospective cohort study in a UK Biobank population for the purposes of validating the C-Score and developing and comparatively validating variations of the score using statistical and ML models to assess the balance between expediency and ease of interpretability and model complexity. Primary and secondary outcome measures were discrimination of a points-based score for all-cause mortality within 10 years (Harrell c-statistic) and discrimination and calibration of Cox proportional hazards models and ML models that incorporate C-Score values (or raw data inputs) and other predictors to predict the risk of all-cause mortality within 10 years. RESULTS: The study cohort comprised 420,560 individuals. During a cohort follow-up of 4,526,452 person-years, there were 16,188 deaths from any cause (3.85%). The points-based model had good discrimination (c-statistic=0.66). There was a 31% relative reduction in risk of all-cause mortality per decile of increasing C-Score (hazard ratio of 0.69, 95% CI 0.663-0.675). A Cox model integrating age and C-Score had improved discrimination (8 percentage points; c-statistic=0.74) and good calibration. ML approaches did not offer improved discrimination over statistical modeling. CONCLUSIONS: The novel health metric ("C-Score") has good predictive capabilities for all-cause mortality within 10 years. Embedding the C-Score within a smartphone app may represent a useful tool for democratized, individualized health risk prediction. A simple Cox model using C-Score and age balances parsimony and accuracy of risk predictions and could be used to produce absolute risk estimations for app users.Chelsea Digital VenturesHuma Therapeutic
Networking Our Way to Better Ecosystem Service Provision.
The ecosystem services (EcoS) concept is being used increasingly to attach values to natural systems and the multiple benefits they provide to human societies. Ecosystem processes or functions only become EcoS if they are shown to have social and/or economic value. This should assure an explicit connection between the natural and social sciences, but EcoS approaches have been criticized for retaining little natural science. Preserving the natural, ecological science context within EcoS research is challenging because the multiple disciplines involved have very different traditions and vocabularies (common-language challenge) and span many organizational levels and temporal and spatial scales (scale challenge) that define the relevant interacting entities (interaction challenge). We propose a network-based approach to transcend these discipline challenges and place the natural science context at the heart of EcoS research.The QUINTESSENCE Consortium gratefully acknowledges the support of DĂ©partment SPE and MĂ©taprogramme ECOSERV of INRA, and the French ANR projects PEERLESS (ANR-12-AGRO-0006) and AgroBioSE (ANR-13-AGRO-0001).This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.tree.2015.12.00
Periodic Host Absence Can Select for Higher or Lower Parasite Transmission Rates
This paper explores the effect of discontinuous periodic host absence on the evolution of pathogen transmission rates by using Ro maximisation techniques. The physiological consequence of an increased transmission rate can be either an increased virulence, i.e. there is a transmission-virulence trade-off or ii) a reduced between season survival, i.e. there is a transmission-survival trade-off. The results reveal that the type of trade-off determines the direction of selection, with relatively longer periods of host absence selecting for higher transmission rates in the presence of a trade-off between transmission and virulence but lower transmission rates in the presence of a trade-of between transmission and between season survival. The fact that for the transmission-virulence trade-off both trade-off parameters operate during host presence whereas for the transmission-survival trade-off one operates during host presence (transmission) and the other (survival) during the period of host absence is the main cause for this difference in selection direction. Moreover, the period of host absence seems to be the key determinant of the pathogens transmission rate. Comparing plant patho-systems with contrasting biological features suggests that airborne plant pathogen respond differently to longer periods of host absence than soil-borne plant pathogens
Pathogen Populations Evolve to Greater Race Complexity in Agricultural Systems â Evidence from Analysis of Rhynchosporium secalis Virulence Data
Fitness cost associated with pathogens carrying unnecessary virulence alleles is the fundamental assumption for preventing the emergence of complex races in plant pathogen populations but this hypothesis has rarely been tested empirically on a temporal and spatial scale which is sufficient to distinguish evolutionary signals from experimental error. We analyzed virulence characteristics of âŒ1000 isolates of the barley pathogen Rhynchosporium secalis collected from different parts of the United Kingdom between 1984 and 2005. We found a gradual increase in race complexity over time with a significant correlation between sampling date and race complexity of the pathogen (r20â=â0.71, pâ=â0.0002) and an average loss of 0.1 avirulence alleles (corresponding to an average gain of 0.1 virulence alleles) each year. We also found a positive and significant correlation between barley cultivar diversity and R. secalis virulence variation. The conditions assumed to favour complex races were not present in the United Kingdom and we hypothesize that the increase in race complexity is attributable to the combination of natural selection and genetic drift. Host resistance selects for corresponding virulence alleles to fixation or dominant frequency. Because of the weak fitness penalty of carrying the unnecessary virulence alleles, genetic drift associated with other evolutionary forces such as hitch-hiking maintains the frequency of the dominant virulence alleles even after the corresponding resistance factors cease to be used
Weeds, as ancillary hosts, pose disproportionate risk for virulent pathogen transfer to crops
Les collines euganéennes
Le Lannou Maurice, Fontvieille J.-L. Les collines euganéennes. In: Revue de géographie jointe au Bulletin de la Société de géographie de Lyon et de la région lyonnaise, vol. 25, n°1, 1950. pp. 28-37
Pesanteur et comportement (approche psychophysiologique)
Summary
The authors give an account of the methods used to simulate hyper-gravity and weightlessness. They study the sensory receptors which are sensitive to gravity, among which specialized receptors (those of the inner ear) can be distinguished from unspecialized ones (tactile, visual, proprioceptive receptors). In light of the most recent works, they investigate the influence of gravity on reproduction and development, vegetative functions, posture and motricity, perception of verticality, and sleep. In conclusion, the authors specify the complex sensory integration by which gravity influences behaviour, and also consider the gravity-avoidance behaviour of animals.Résumé
Les auteurs exposent d'abord les méthodes utilisées pour simuler l'accroissement de pesanteur et l'impesanteur. Ils étudient ensuite les récepteurs sensoriels sensibles à la pesanteur, parmi lesquels on peut distinguer des récepteurs spécialisés (ceux del'oreille interne), et non spécialisés (récepteurs tactiles, visuels, proprioceptifs). Enfin, à la lumiÚre des travaux les plus récents, ils examinent l'influence de la gravité sur la reproduction et le développement, les fonctions végétatives, la posture et la motricité, la perception de la verticalité, le sommeil. En conclusion, les auteurs précisent l' intégration sensorielle complexe par laquelle la pesanteur agit sur le comportement, et envisagent le comportement de choix vis-à -vis de la gravité.Caston J., Cazin L., Gribenski A., Lannou J. Pesanteur et comportement (approche psychophysiologique). In: L'année psychologique. 1976 vol. 76, n°1. pp. 145-175
Microcomputer-based system for human sperm motility assessment and spermatozoon track analysis
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