978 resultados para Stratification chimique


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Objectives: Catechol-O-methyltransferase plays a central role in the metabolism of biogenic amines such as norepinephrine, dopamine and serotonin. Functional studies have demonstrated a dose relationship between Val158Met genotypes and catechol-O-methyltransferase activity. Compared with the Val158Val genotype, the Val158Met and Met158Met genotypes result in two- and four-fold reductions in catechol-O-methyltransferase activity, respectively. Two recent reports have observed the association between the Met158Met genotype and risk of anxiety in adult populations. We examined the association between the Val158Met genotypes and propensity to anxiety across adolescence.

Methods: Participants were drawn from an eight-wave study of the mental and behavioural health of over 2000 young Australians followed from 14 to 24 years of age (Victorian Adolescent Health Cohort Study, 1992 to present). DNA was received from 962 participants using a cheek swab collection method.

Results: The odds of reporting persistent episodic anxiety (phobic avoidance, panic attacks) were doubled among carriers of the Met158Met genotype (odds ratio 2.0, 95% confidence interval 1.1-3.4, P=0.014). A dose relationship between additional copies of the Met158 allele and persistent episodic anxiety was also observed (1.5, 1.1-1.94, P=0.007). Stratification by sex showed that the risk effect of the Met158 allele was among females only. No association was observed for measures of neuroticism, persistent generalized anxiety, or a composite measure of psychiatric distress.

Conclusion: These data replicate previous findings suggesting association between the Val158Met polymorphism and specific expressions of anxiety among females.

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We performed a double-blind placebo-controlled trial to study whether early treatment with erythropoietin could prevent the development of acute kidney injury in patients in two general intensive care units. As a guide for choosing the patients for treatment we measured urinary levels of two biomarkers, the proximal tubular brush border enzymes γ-glutamyl transpeptidase and alkaline phosphatase. Randomization to either placebo or two doses of erythropoietin was triggered by an increase in the biomarker concentration product to levels above 46.3, with a primary outcome of relative average plasma creatinine increase from baseline over 4 to 7 days. Of 529 patients, 162 were randomized within an average of 3.5 h of a positive sample. There was no difference in the incidence of erythropoietin-specific adverse events or in the primary outcome between the placebo and treatment groups. The triggering biomarker concentration product selected patients with more severe illness and at greater risk of acute kidney injury, dialysis, or death; however, the marker elevations were transient. Early intervention with high-dose erythropoietin was safe but did not alter the outcome. Although these two urine biomarkers facilitated our early intervention, their transient increase compromised effective triaging. Further, our study showed that a composite of these two biomarkers was insufficient for risk stratification in a patient population with a heterogeneous onset of injury.

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The report presents most recent information on participation in cervical screening, rate of early re-screening, low-grade and high-grade abnormalities detected, incidence of cervical cancer and mortality. Analyses of incidence and mortality data by location (major cities, regional and remote) as well as mortality by Indigenous status are also presented. Where possible, data are presented by state and territory stratification.

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This is the third annual report based on key program activity, performance and outcome indicators to monitor the achievements of the National Cervical Screening Program. The report provides a comprehensive national picture of cervical screening in Australia for 2000-2001 and 1999-2000. The report presents most recent information on participation in cervical screening, rate of early rescreening, low-grade and high-grade abnormalities detected, incidence of cervical cancer and mortality. Analysis of incidence and mortality data by location (rural, remote and metropolitan) as well as mortality by Indigenous status are also presented. Where possible, data are presented by state and territory stratification.

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It is surprising to discover during early doctoral research that there is a paucity of Australian scholarship using Bourdieu’s theoretical tools in the field of law, and in the sub-field of post-graduate pre-admission practical legal training. This article introduces Bourdieu’s conceptions of habitus, field, categories of capital, symbolic violence, and misrecognition. It describes how Bourdieu applied these tools to identify structural hostility between legal academics and practitioners, and the struggles for control in the field of law. Review of three North American studies that used Bourdieu’s theories follows, involving law students’ habitus in transition, class stratification in legal education, and gender stratification in law firm partnerships. Drawing on three internally connected ‘moments’ necessary to use Bourdieu’s tools, together with four critical questions concerning teachers’ engagement with the scholarship of teaching, this article identifies new questions for investigation. These questions will frame further research to discover whether the objective structures of the practical legal training field and the habitus of legal practitioners constrains them to act as ‘fish out of water’ in the context of a scholarship of teaching.

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An Australian research facility, conducted a study on several different school classrooms in regards to their thermal comfort, CO2 levels, air temperature stratification and ventilation rates in a selection of Victorian (Melbourne, Australia) schools during a winter season. A brief literature review reveals similar IAQ problems elsewhere (outside Australia) and suggests several HVAC concepts that provide potential solutions. Our intention is to highlight particular IAQ discrepancies in existing school classroom design resulting from these case study measurements, suggesting construction and mechanical operational conditioning improvements.In particular this research confirms the urgency and necessity of addressing IAQ problems in schools, world wide. Our results of the Australian school classroom measurements are similar to other parts of the world, indicating that CO2 levels, ventilation rates and air temperatures are non-compliant with the standards.

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Considerable variability in survival rate after an acute myocardial infarction exists and accurate risk stratification is of significant importance. The American College of Cardiology and the American Heart Association has recommended early risk stratification using several clinical risk scoring instruments to identify high risk patients. The aim of this paper is to identify secondary cardiovascular risk scoring instruments that could be utilized at the time of intervention for acute coronary syndromes and compare their psychometric properties as they were developed. A search using Medline, Cumulative Index to Nursing and Allied Health Literature and the Psychology and Behavioral Sciences Collection data-bases identified studies published between January 1990 and January 2010 used to measure risk after intervention for acute coronary syndrome. Four validated secondary risk prediction scoring instruments were identified for comparison.Secondary risk prediction scoring instruments for the acute coronary syndrome patient population are evidence based, valid and reliable. Use of the instruments by cardiac focused clinicians will aid in the determination of treatment strategies, and estimation of short and long term events and mortality.

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Objective
To investigate the relationship between excess weight (overweight and obesity) and health-related quality of life (HRQoL) in a sample of secondary school children in Fiji, by gender, age and ethnicity.

Methods
The study comprised 8947 children from forms 3–6 (age 12–18 years) in 18 secondary schools on Viti Levu, the main island of Fiji. Body mass index (BMI) was calculated from measured height and weight, and weight status was classified according to the International Obesity Task Force recommendations. HRQoL was measured by the self-report version of the Pediatric Quality of Life Inventory 4.0.

Results

HRQoL was similar in children with obesity and normal weight. Generally, this was replicated when analyzed separately by gender and ethnicity, but age stratification revealed disparities. In 12–14-year-old children, obesity was associated with better HRQoL, owing to better social and school functioning and well-being, and in 15–18-year olds with poorer HRQoL, owing to worse physical, emotional and social functioning and well-being (Cohen’s d 0.2–0.3). Children with a BMI in the overweight range also reported a slightly lower HRQoL than children with a BMI in the normal weight range, but although statistically significant, the size of this difference was trivial (Cohen’s d <0.2).

Discussion

The results suggest that, overall there is no meaningful negative association between excess weight and HRQoL in secondary school children in Fiji. This is in contradiction to the negative relationship between excess weight and HRQoL shown in studies from other countries and cultures. The assumption that a large body size is associated with a lower quality of life cannot be held universally. Although a generally low HRQoL among children in Fiji may be masking or overriding the potential effect of excess weight on HRQoL, socio-economic and/or socio-cultural factors, may help to explain these relationships.

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Medulloblastoma is curable in approximately 70% of patients. Over the past decade, progress in improving survival using conventional therapies has stalled, resulting in reduced quality of life due to treatment-related side effects, which are a major concern in survivors. The vast amount of genomic and molecular data generated over the last 5-10 years encourages optimism that improved risk stratification and new molecular targets will improve outcomes. It is now clear that medulloblastoma is not a single-disease entity, but instead consists of at least four distinct molecular subgroups: WNT/Wingless, Sonic Hedgehog, Group 3, and Group 4. The Medulloblastoma Down Under 2013 meeting, which convened at Bunker Bay, Australia, brought together 50 leading clinicians and scientists. The 2-day agenda included focused sessions on pathology and molecular stratification, genomics and mouse models, high-throughput drug screening, and clinical trial design. The meeting established a global action plan to translate novel biologic insights and drug targeting into treatment regimens to improve outcomes. A consensus was reached in several key areas, with the most important being that a novel classification scheme for medulloblastoma based on the four molecular subgroups, as well as histopathologic features, should be presented for consideration in the upcoming fifth edition of the World Health Organization's classification of tumours of the central nervous system. Three other notable areas of agreement were as follows: (1) to establish a central repository of annotated mouse models that are readily accessible and freely available to the international research community; (2) to institute common eligibility criteria between the Children's Oncology Group and the International Society of Paediatric Oncology Europe and initiate joint or parallel clinical trials; (3) to share preliminary high-throughput screening data across discovery labs to hasten the development of novel therapeutics. Medulloblastoma Down Under 2013 was an effective forum for meaningful discussion, which resulted in enhancing international collaborative clinical and translational research of this rare disease. This template could be applied to other fields to devise global action plans addressing all aspects of a disease, from improved disease classification, treatment stratification, and drug targeting to superior treatment regimens to be assessed in cooperative international clinical trials.

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Monitoring the abundance and distribution of taxa is essential to assess their contribution to ecosystem processes. For marine taxa that are difficult to study or have long been perceived of little ecological importance, quantitative information is often lacking. This is the case for jellyfish (medusae and other gelatinous plankton). In the present work, 4 years of scyphomedusae by-catch data from the 2007-2010 Irish Sea juvenile gadoid fish survey were analysed with three main objectives: (1) to provide quantitative and spatially-explicit species-specific biomass data, for a region known to have an increasing trend in jellyfish abundance; (2) to investigate whether year-to-year changes in catch-biomass are due to changes in the numbers or in the size of medusa (assessed as the mean mass per individual), and (3) to determine whether inter-annual variation patterns are consistent between species and water masses. Scyphomedusae were present in 97% of samples (N=306). Their overall annual median catch-biomass ranged from 0.19 to 0.92gm-3 (or 8.6 to 42.4gm-2). Aurelia aurita and Cyanea spp. (Cyanea lamarckii and Cyanea capillata) made up 77.7% and 21.5% of the total catch-biomass respectively, but species contributions varied greatly between sub-regions and years. No consistent pattern was detected between the distribution and inter-annual variations of the two genera, and contrasting inter-annual patterns emerged when considering abundance either as biomass or as density. Significantly, A.aurita medusae were heavier in stratified than in mixed waters, which we hypothesize may be linked to differences in timing and yield of primary and secondary productions between water masses. These results show the vulnerability of time-series from bycatch datasets to phenological changes and highlight the importance of taking species- and population-specific distribution patterns into account when integrating jellyfish into ecosystem models.

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OBJECTIVES: Equity and fairness at work are associated with a range of organizational and health outcomes. Past research suggests that workers with disabilities experience inequity in the workplace. It is difficult to conclude whether the presence of disability is the reason for perceived unfair treatment due to the possible confounding of effect estimates by other demographic or socioeconomic factors. METHODS: The data source was the Household, Income, and Labor Dynamics in Australia (HILDA) survey (2001-2012). Propensity for disability was calculated from logistic models including gender, age, education, country of birth, and father's occupational skill level as predictors. We then used nearest neighbor (on propensity score) matched analysis to match workers with disabilities to workers without disability. RESULTS: Results suggest that disability is independently associated with lower fairness of pay after controlling for confounding factors in the propensity score matched analysis; although results do suggest less than half a standard deviation difference, indicating small effects. Similar results were apparent in standard multivariable regression models and alternative propensity score analyses (stratification, covariate adjustment using the propensity score, and inverse probability of treatment weighting). CONCLUSIONS: Whilst neither multivariable regression nor propensity scores adjust for unmeasured confounding, and there remains the potential for other biases, similar results for the two methodological approaches to confounder adjustment provide some confidence of an independent association of disability with perceived unfairness of pay. Based on this, we suggest that the disparity in the perceived fairness of pay between people with and without disabilities may be explained by worse treatment of people with disabilities in the workplace.

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Results are presented from a series of model studies of the transient exchange flow resulting from the steady descent of an impermeable barrier separating initially-quiescent fresh and saline water bodies having density ρ0 and ρ0 + (Δρ)0, respectively. A set of parametric laboratory experiments has been carried out (i) to determine the characteristic features of the time-dependent exchange flow over the barrier crest and (ii) to quantify the temporal increase in the thickness and spatial extent of the brackish water reservoir formed behind the barrier by the outflowing, partly-mixed saline water. The results of the laboratory experiments have been compared with the predictions of a theoretical model adapted from the steady, so-called maximal exchange flow case and good qualitative agreement between theory and experiment has been demonstrated. The comparisons indicate that head losses of between 7% and 3% are applicable to the flow over the ridge crest in the early and late stages, respectively, of the barrier descent phase, with these losses being attributed to mixing processes associated with the counterflowing layers of fresh and saline water in the vicinity of the ridge crest. The experimental data show (and the theoretical model predictions confirm) that (i) the dimensionless time of detection tdet (g′/Hb)1/2 of the brackish water pool fed by the dense outflow increases (at a given distance from the barrier) with increasing values of the descent rate parameter g'Hb/(dhb/dt)2 and (ii) the normalised thickness δ(x,t)/Hb of the pool at a given reference station increases monotonically with increasing values of the modified time (t - tdet)/(Hb/g′) 1/2, with the rate of thickening decreasing with increasing values of the descent rate parameter g'Hb (dhb/dt)2. Here, g′ = (g/ρ0) (Δρ)0 is the modified gravitational acceleration, Hb is the mean depth of the water and dhb/dt denotes the rate of descent of the barrier height hb with elapsed time t after the two water bodies are first brought into contact. © 2004 Kluwer Academic Publishers.

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The trajectories and stability of self-reported sleep duration recorded at ages 13, 15, and 23 years on reported sleep duration at age 30 years among 1105 students (55% male) who participated in the Norwegian Longitudinal Health and Behaviour Study were examined. Questionnaire data were used to obtain demographic and sleep variables. Dichotomised short sleep duration was based on normative values and set as ≤8.5 h (age 13 years), ≤8 h (age 15 years) and ≤7 h (ages 23 and 30 years). Results indicated a significant overall reduction in total sleep duration (h per night) across age groups. Sleep duration (continuous) at age 15 and 23 years (whole group) was moderately but positively correlated with sleep duration at age 30 years (P < 0.01). When split by sex, at age 15 years, this association was present among females only (P < 0.01); however, at age 23 years, this association was present in both male and females (both P < 0.001). Categorical short sleep at age 23 years (whole group) was associated with short sleep at age 30 years (unadjusted odds ratio = 3.67, 95% confidence interval 2.36-5.69). Following sex stratification, this effect was significant for both males (unadjusted odds ratio = 3.77, 95% confidence interval: 2.22-6.42) and females (unadjusted odds ratio = 2.71, 95% confidence interval: 1.46-5.04). No associations were noted for categorical short sleep at ages 13 or 15 years, and subsequent short sleep at 30 years. Habitual short sleep duration during middle adulthood is not sustained from the time of early adolescence. Rather, these trends appear to be formed during early adulthood.

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BACKGROUND: Colorectal surgery carries a significant mortality risk, with reported rates of 1-6% for elective surgery and up to 22% in the emergency setting. Both clinicians and patients will benefit from being able to predict the likelihood of death before surgery. Recently, we have described and validated two risk stratification models for colorectal surgery, the Barwon Health 2012 and Association Française de Chirurgie models. However, these models are not suitable for assessment at patient's bedside. The purpose of this study is to develop a simplified preoperative model capable of predicting mortality following colorectal surgery. METHODS: The new model is termed Colorectal preOperative Surgical Score (CrOSS). The development and internal validation of CrOSS was performed using a prospectively maintained colorectal database. External validation was performed using retrospective data. Univariate and multivariate analyses were performed in model development. Calibration and discrimination were used for model validation. RESULTS: There were 474 and 389 consecutive colorectal surgeries at Geelong Hospital and Western Hospital. Overall mortality rates were 5.16% and 1.03%, respectively. Significant predictors for mortality were as follows: age ≥70, urgent operation, albumin ≤30 g/L and congestive heart failure (receiver operating characteristic (ROC) = 0.870, calibration P-value = 0.937). The predicted risk of mortality was stratified according to the risk profile of 0.39-66.51%. When validated externally, CrOSS predicted mortality accurately (ROC = 0.847, calibration P-value = 0.199). CONCLUSIONS: A robust and simple preoperative model has been created to risk-stratify patients for colorectal surgery. This was successfully validated at another tertiary hospital.

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Electronic medical record (EMR) offers promises for novel analytics. However, manual feature engineering from EMR is labor intensive because EMR is complex - it contains temporal, mixed-type and multimodal data packed in irregular episodes. We present a computational framework to harness EMR with minimal human supervision via restricted Boltzmann machine (RBM). The framework derives a new representation of medical objects by embedding them in a low-dimensional vector space. This new representation facilitates algebraic and statistical manipulations such as projection onto 2D plane (thereby offering intuitive visualization), object grouping (hence enabling automated phenotyping), and risk stratification. To enhance model interpretability, we introduced two constraints into model parameters: (a) nonnegative coefficients, and (b) structural smoothness. These result in a novel model called eNRBM (EMR-driven nonnegative RBM). We demonstrate the capability of the eNRBM on a cohort of 7578 mental health patients under suicide risk assessment. The derived representation not only shows clinically meaningful feature grouping but also facilitates short-term risk stratification. The F-scores, 0.21 for moderate-risk and 0.36 for high-risk, are significantly higher than those obtained by clinicians and competitive with the results obtained by support vector machines.