995 resultados para centrality measures


Relevância:

20.00% 20.00%

Publicador:

Resumo:

During the adolescent years, substance use, anti-social behaviours and overweight/obesity are amongst the major public health concerns. We investigate if risk and protective factors associated with adolescent problem behaviours and substance use are also associated with weight status in young Australian adolescents. Data comes from the 2006 Healthy Neighbourhoods study, a cross-sectional survey of students attending primary (grade 6, mean age 11) and secondary (grade 8, mean age 12) schools in 30 communities across Australia. Adolescents were classified as not overweight, overweight or obese according to international definitions. Logistic and linear regression analyses, adjusted for age, gender and socio-economic disadvantage quartile, were used to quantify associations between weight status (or BMI z-score) and the cumulative number of problem behaviour risk and protective factors. Prevalence of overweight and obesity was 22.6 % (95 % confidence interval (CI), 21.2–24.0 %) and 7.2 % (CI, 6.3–8.3 %). Average number of risk and protective factors present was 4.0 (CI, 3.7–4.2) and 6.2 (CI, 6.1–6.3). Independently, total number of risk factors present was positively associated with likelihood of overweight and obesity, while number of protective factors present was inversely associated with the likelihood of being above a healthy weight. When both risk and protective factors were included in a regression model, only risk factors were associated with the likelihood of being overweight or obese. Average BMI z-score increased by 0.03 units with each additional risk factor present. Prevention programmes targeting developmental risk and protective factors in adolescents that reduce substance use and problem behaviours may also benefit physical health.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Rationale Cardiac metabolism is thought to be altered in insulin resistance and type 2 diabetes (T2D). Our understanding of the regulation of cardiac substrate metabolism and insulin sensitivity has largely been derived from ex vivo preparations which are not subject to the same metabolic regulation as in the intact heart in vivo. Studies are therefore required to examine in vivo cardiac glucose metabolism under physiologically relevant conditions. Objective To determine the temporal pattern of the development of cardiac insulin resistance and to compare with dynamic approaches to interrogate cardiac glucose and intermediary metabolism in vivo. Methods and results Studies were conducted to determine the evolution of cardiac insulin resistance in C57Bl/6 mice fed a high-fat diet (HFD) for between 1 and 16 weeks. Dynamic in vivo cardiac glucose metabolism was determined following oral administration of [U-13C] glucose. Hearts were collected after 15 and 60 min and flux profiling was determined by measuring 13C mass isotopomers in glycolytic and tricarboxylic acid (TCA) cycle intermediates. Cardiac insulin resistance, determined by euglycemic-hyperinsulinemic clamp, was evident after 3 weeks of HFD. Despite the presence of insulin resistance, in vivo cardiac glucose metabolism following oral glucose administration was not compromised in HFD mice. This contrasts our recent findings in skeletal muscle, where TCA cycle activity was reduced in mice fed a HFD. Similar to our report in muscle, glucose derived pyruvate entry into the TCA cycle in the heart was almost exclusively via pyruvate dehydrogenase, with pyruvate carboxylase mediated anaplerosis being negligible after oral glucose administration. Conclusions Under experimental conditions which closely mimic the postprandial state, the insulin resistant mouse heart retains the ability to stimulate glucose metabolism.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background Monitoring athlete well-being is essential to guide training and to detect any progression towards negative health outcomes and associated poor performance. Objective (performance, physiological, biochemical) and subjective measures are all options for athlete monitoring. Objective We systematically reviewed objective and subjective measures of athlete well-being. Objective measures, including those taken at rest (eg, blood markers, heart rate) and during exercise (eg, oxygen consumption, heart rate response), were compared against subjective measures (eg, mood, perceived stress). All measures were also evaluated for their response to acute and chronic training load. Methods The databases Academic search complete, MEDLINE, PsycINFO, SPORTDiscus and PubMed were searched in May 2014. Fifty-six original studies reported concurrent subjective and objective measures of athlete well-being. The quality and strength of findings of each study were evaluated to determine overall levels of evidence. Results Subjective and objective measures of athlete well-being generally did not correlate. Subjective measures reflected acute and chronic training loads with superior sensitivity and consistency than objective measures. Subjective well-being was typically impaired with an acute increase in training load, and also with chronic training, while an acute decrease in training load improved subjective well-being. Summary This review provides further support for practitioners to use subjective measures to monitor changes in athlete well-being in response to training. Subjective measures may stand alone, or be incorporated into a mixed methods approach to athlete monitoring, as is current practice in many sport settings.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Obesity is a risk factor for cancer. However, it is not known if general adiposity, as measured by body mass index (BMI) or central adiposity [e.g., waist circumference (WC)] have stronger associations with cancer, or which anthropometric measure best predicts cancer risk. We included 79,458 men and women from the Australian and New Zealand Diabetes and Cancer Collaboration with complete data on anthropometry [BMI, WC, Hip Circumference (HC), WHR, waist to height ratio (WtHR), A Body Shape Index (ABSI)], linked to the Australian Cancer Database. Cox proportional hazards models assessed the association between each anthropometric marker, per standard deviation and the risk of overall, colorectal, post-menopausal (PM) breast, prostate and obesity-related cancers. We assessed the discriminative ability of models using Harrell's c-statistic. All anthropometric markers were associated with overall, colorectal and obesity-related cancers. BMI, WC and HC were associated with PM breast cancer and no significant associations were seen for prostate cancer. Strongest associations were observed for WC across all outcomes, excluding PM breast cancer for which HC was strongest. WC had greater discrimination compared to BMI for overall and colorectal cancer in men and women with c-statistics ranging from 0.70 to 0.71. We show all anthropometric measures are associated with the overall, colorectal, PM breast and obesity-related cancer in men and women, but not prostate cancer. WC discriminated marginally better than BMI. However, all anthropometric measures were similarly moderately predictive of cancer risk. We do not recommend one anthropometric marker over another for assessing an individuals' risk of cancer.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This study examines the relationship between employee voice and job satisfaction using data from the 2007 Australian Workplace Representation Survey (AWRPS) of 1,022 employees. Drawing on human resource management and industrial relations literature, we test hypotheses concerning the relationship between direct and union voice arrangements and job satisfaction. This relationship represents a gap in the literature, which is important from both theoretical and practical perspectives. Controlling for a range of personal, job, and workplace characteristics, regression analyses suggest that although evidence of voice complementarity exists, direct voice appears to be the central voice arrangement underpinning employees’ job satisfaction. The article concludes by highlighting the study’s implications for management practice and identifi es avenues for further research.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this work we examine the reliability and validity (in comparison to magnetic resonance imaging; MRI) of real-time ultrasound measures of lumbar erector spinae thickness. We also consider the between-day reliability of the lumbar multifidus muscle area as measured via ultrasound. 23 male subjects aged 21-45 years were measured three times over the course of nine days by one operator. The first (L1) through to the fifth (L5) lumbar vertebral levels were measured on the left and right sides. MRI was performed on the same day as first ultrasound scanning. For between-day intra-rater reliability, intra-class correlation co-efficients (ICCs), standard error of the measurement, minimal detectable difference and co-efficients of variation (CVs) were calculated along with their 95% confidence intervals and Bland-Altman analysis was performed. On Bland-Altman analysis, erector spinae thickness and multifidus area ultrasound measures 'agreed' with equivalent MR measures, though the correlation between MR and ultrasound measures was typically poor to moderate. For both ultrasound measures, the ICCs ranged from 'moderate' to 'excellent' at individual vertebral levels, although multifidus area (CV ranged from 8 to 15%) was less reliable than erector spinae thickness (CV ranged from 6 to 10%). 'Agreement' on Bland-Altmann analysis was present between days for all ultrasound measures. Averaging between sides and between vertebral levels improved reliability. Average erector spinae thickness showed a CV of 5.5% (ICC 0.77) and average multifidus area 6.2% (ICC 0.80).

Relevância:

20.00% 20.00%

Publicador:

Resumo:

 The outcomes of the current study suggest employee performance should be taken into account when examining the effects of stress-related working conditions. Furthermore, the current study highlights the need to pay careful attention to the types of analyses that are undertaken in stressor-performance research and not to assume the relationship between stress-related working conditions and employee performance parallels the stressor-health literature.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background: It has been suggested that young people should develop competence in a variety of ‘lifelong physical activities’ to ensure that they can be active across the lifespan. Objective: The primary aim of this systematic review is to report the methodological properties, validity, reliability, and test duration of field-based measures that assess movement skill competency in lifelong physical activities. A secondary aim was to clearly define those characteristics unique to lifelong physical activities. Data Sources: A search of four electronic databases (Scopus, SPORTDiscus, ProQuest, and PubMed) was conducted between June 2014 and April 2015 with no date restrictions. Study Selection: Studies addressing the validity and/or reliability of lifelong physical activity tests were reviewed. Included articles were required to assess lifelong physical activities using process-oriented measures, as well as report either one type of validity or reliability. Study Appraisal and Synthesis Methods: Assessment criteria for methodological quality were adapted from a checklist used in a previous review of sport skill outcome assessments. Results: Movement skill assessments for eight different lifelong physical activities (badminton, cycling, dance, golf, racquetball, resistance training, swimming, and tennis) in 17 studies were identified for inclusion. Methodological quality, validity, reliability, and test duration (time to assess a single participant), for each article were assessed. Moderate to excellent reliability results were found in 16 of 17 studies, with 71 % reporting inter-rater reliability and 41 % reporting intra-rater reliability. Only four studies in this review reported test–retest reliability. Ten studies reported validity results; content validity was cited in 41 % of these studies. Construct validity was reported in 24 % of studies, while criterion validity was only reported in 12 % of studies. Limitations: Numerous assessments for lifelong physical activities may exist, yet only assessments for eight lifelong physical activities were included in this review. Generalizability of results may be more applicable if more heterogeneous samples are used in future research. Conclusion: Moderate to excellent levels of inter- and intra-rater reliability were reported in the majority of studies. However, future work should look to establish test–retest reliability. Validity was less commonly reported than reliability, and further types of validity other than content validity need to be established in future research. Specifically, predictive validity of ‘lifelong physical activity’ movement skill competency is needed to support the assertion that such activities provide the foundation for a lifetime of activity.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

RESEARCH HANDBOOKS IN FINANCIAL LAW Series Editor: Rosa Lastra, Queen Mary, University of London, UK This important new Handbook series presents high quality, original reference works that cover a range of subjects within the ...

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We adapted/developed and examined the test–retest reliability and internal consistency of eight parent-report measures of home and neighborhood environmental correlates of physical activity appropriate for Chinese preschool-aged children and their parents/primary caregivers living in densely populated urban environments. This study consisted of a qualitative (cognitive interviews) and a quantitative (test–retest reliability) component. Chinese versions of the measures were pilot-tested on 20 parents of Hong Kong preschool-aged children using cognitive interviews. Measures were then administered to 61 parents twice, 1 week apart. Test–retest reliability and internal consistency were computed. Except for two items, the test–retest reliability of items and scale summary scores ranged from moderate to excellent. The internal consistency of the measures exceeded recommended minimal values (Cronbach’s α >.70). The parent-report measures examined in this study are potentially appropriate for use in investigations of environmental correlates of the physical activity of Chinese preschool-aged children living in densely populated urban environments. However, their predictive validity with respect to Chinese preschool-aged children’s physical activity needs to be assessed in future studies.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This thesis provides theoretical and applied support for the use of self-report measures for athlete monitoring. Athlete self-report measures were found to effectively reflect the training response, whilst also providing a means to improve communication, confidence, and regulation of athletic preparation. Context-specific guidelines for implementation were also identified.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Certain tasks in image processing require the preservation of fine image details, while applying a broad operation to the image, such as image reduction, filtering, or smoothing. In such cases, the objects of interest are typically represented by small, spatially cohesive clusters of pixels which are to be preserved or removed, depending on the requirements. When images are corrupted by the noise or contain intensity variations generated by imaging sensors, identification of these clusters within the intensity space is problematic as they are corrupted by outliers. This paper presents a novel approach to accounting for spatial organization of the pixels and to measuring the compactness of pixel clusters based on the construction of fuzzy measures with specific properties: monotonicity with respect to the cluster size; invariance with respect to translation, reflection, and rotation; and discrimination between pixel sets of fixed cardinality with different spatial arrangements. We present construction methods based on Sugeno-type fuzzy measures, minimum spanning trees, and fuzzy measure decomposition. We demonstrate their application to generating fuzzy measures on real and artificial images.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Market timing performance of mutual funds is usually evaluated with linear models with dummy variables which allow for the beta coefficient of CAPM to vary across two regimes: bullish and bearish market excess returns. Managers, however, use their predictions of the state of nature to deÞne whether to carry low or high beta portfolios instead of the observed ones. Our approach here is to take this into account and model market timing as a switching regime in a way similar to Hamilton s Markov-switching GNP model. We then build a measure of market timing success and apply it to simulated and real world data.