Individual, social and physical environmental correlates of children's active free-play : a cross-sectional study

Background
Children's unstructured outdoor free-play (or active free-play) has the potential to make an important contribution to children's overall physical activity levels. Limited research has, however, examined physical activity in this domain. This study examined associations between individual, social and physical environmental factors and the frequency with which children play in particular outdoor locations outside school hours. This study also investigated whether the frequency of playing in outdoor locations was associated with children's overall physical activity levels.

Methods
Participants including 8-9 year old children and their parents (n = 187) were recruited from a selection of primary schools of varying socioeconomic status across metropolitan Melbourne, Australia. Parents completed a survey and children's overall physical activity levels were measured by accelerometry. Regression models examined the odds of children playing in various outdoor settings according to particular correlates.

Results
Inverse associations were found between preference for activities not involving physical activity, and the likelihood of children playing in the yard at home on the weekend (OR = 0.65; CI = 0.45,0.95). Positive correlates of children playing in their own street included: parental perceptions that it was safe for their child to play in their street (weekdays [OR = 6.46; CI = 2.84,14.71], weekend days [OR = 6.01; CI = 2.68,13.47]); children having many friends in their neighbourhood (OR = 2.63; CI = 1.21,5.76); and living in a cul-de-sac (weekdays [OR = 3.99; CI = 1.65,9.66], weekend days [OR = 3.49; CI = 1.49,8.16]). Positive correlates of more frequent play in the park/playground on weekdays included family going to the park together on a weekly basis on weekdays (OR = 6.8; CI = 3.4,13.6); and on weekend days (OR = 7.36; CI = 3.6,15.0). No differences in mean mins/day of moderate-vigorous physical activity were found between children in the highest and lowest tertiles for frequency of playing in particular outdoor locations.

Conclusion
The presence of friends, safety issues and aspects of the built environment were reported by parents to be associated with children's active free-play in outdoor locations. Future research needs to further examine associations with time spent in active free-play and objectively-measured overall physical activity levels. It is also important to investigate strategies for developing a supportive social and physical environment that provides opportunities for children to engage in active free-play.

Associations between fruit and vegetable intake, leisure-time physical activity, sitting time and self-rated health among older adults : cross-sectional data from the WELL study

Background
Lifestyle behaviours, such as healthy diet, physical activity and sedentary behaviour, are key elements of healthy ageing and important modifiable risk factors in the prevention of chronic diseases. Little is known about the relationship between these behaviours in older adults. The purpose of this study was to explore the relationship between fruit and vegetable (F&V) intake, leisure-time physical activity (LTPA) and sitting time (ST), and their association with self-rated health in older adults.

Methods
This cross-sectional study comprised 3,644 older adults (48% men) aged 55-65 years, who participated in the Wellbeing, Eating and Exercise for a Long Life ("WELL") study. Respondents completed a postal survey about their health and their eating and physical activity behaviours in 2010 (38% response rate). Spearman's coefficient (rho) was used to evaluate the relationship between F&V intake, LTPA and ST. Their individual and shared associations with self-rated health were examined using ordinal logistic regression models, stratified by sex and adjusted for confounders (BMI, smoking, long-term illness and socio-demographic characteristics).

Results
The correlations between F&V intake, LTPA and ST were low. F&V intake and LTPA were positively associated with self-rated health. Each additional serving of F&V or MET-hour of LTPA were associated with approximately 10% higher likelihood of reporting health as good or better among women and men. The association between ST and self-rated health was not significant in the multivariate analysis. A significant interaction was found (ST*F&V intake). The effect of F&V intake on self-rated health increased with increasing ST in women, whereas the effect decreased with increasing ST in men.

Conclusion
This study contributes to the scarce literature related to lifestyle behaviours and their association with health indicators among older adults. The findings suggest that a modest increase in F&V intake, or LTPA could have a marked effect on the health of older adults. Further research is needed to fully understand the correlates and determinants of lifestyle behaviours, particularly sitting time, in this age group.

Excessive alcohol use and its association with risky sexual behaviour: a cross-sectional analysis of data from Victorian secondary school students

Objective
Estimate the prevalence of sexual behaviour and alcohol use and examine the association between excessive alcohol use and risky sexual behaviour in late secondary students in Victoria, Australia.

Method
The sample of Year 11 students from government and independent schools participating in the 2008 International Youth Development Study (n=450) was representative of the Victorian school population. Logistic regression analyses examined the associations between sexual behaviour, binge and compulsive drinking, adjusting for socio-demographic, school and family factors.

Results
Under half (44%) the students had experienced sex in the past year, half (50%) had engaged in binge drinking in the past two weeks and 26% reported compulsive drinking in the past year. Of those who reported sex in the past year (n=197), 34% had sex without a condom at the last sexual encounter and 28% later regretted sex due to alcohol. The likelihood of experiencing sex was increased by binge (OR=2.44, 95%CI 1.44-4.12) and compulsive drinking (OR=2.15, 95%CI 1.29-3.60). For those sexually active, binge drinking increased the risk of having three or more sexual partners (OR=3.37, 95%CI 1.11-10.26) and compulsive drinking increased the likelihood of regretted sex due to alcohol (OR=4.43, 95%CI 2.10-9.31). Excessive drinking was not associated with condom non-use.

Conclusion and implications
Risky sex – multiple sexual partners and regretted sex due to alcohol – and excessive drinking are highly prevalent and co-associated among Victorian late secondary students.

Colorectal preOperative surgical score (CrOSS) for mortality in major colorectal surgery

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.

The role of leverage in cross-border mergers and acquisitions

We examine the relationship between leverage and cross-border mergers and acquisitions. Using a sample of 85,560 cross-border mergers and acquisitions in 57 countries over the period 1990 to 2010, we find that firms with higher leverage are less likely to acquire foreign targets, whereas firms with lower leverage tend to be targets acquired by foreign firms. These effects are more pronounced in Asian countries than North America. Acquisition premium, the likelihood of all-cash offer and the percentage of cash in the acquisition offer decrease with leverage in cross-border mergers and acquisitions. Foreign targets gain positive abnormal returns in the both short run and long run, while acquirers earn positive abnormal returns in the short-run, but negative returns in the long run. We also find that firms adjust their capital structure after the acquisition by issuing more equity if they were overleveraged, or issuing more debt if they were underleveraged before the acquisition. Our results provide international evidence on how leverage affects managerial decision to acquire foreign targets, payment method and acquisition premium in cross-border mergers and acquisitions. This study shows that the interdependent relationship between investment decision and financing decision exists worldwide.

Awareness of energy drink intake guidelines and associated consumption practices: a cross-sectional study

BACKGROUND: Despite concern regarding harms of energy drink (ED) consumption, no research has been conducted to determine awareness and compliance with ED intake guidelines displayed on product packaging in Australia (a novel approach internationally).

METHODS: A convenience sample of 1922 people completed an online survey. Participants reported their knowledge of maximum recommended daily ED intake according to Australian guidelines.

RESULTS: Guideline awareness was reported by 38, 23 and 19 % of past year consumers, lifetime, and non-consumers, respectively. Amongst past year consumers, 'accurate estimators' reported greater ED intake and were more likely to exceed intake guidelines and consume alcohol mixed with ED (AmED). After controlling for demographics and frequency of use, guideline awareness predicted increased likelihood of exceeding guidelines in ED sessions, but was not associated with exceeding ED guidelines in AmED sessions.

CONCLUSIONS: Australia is considered to have the most stringent regulatory approach to EDs internationally. However, advisory statements are not associated with greater awareness and compliance with intake guidelines. Failure to comply with standards for efficacious product labelling, and absence of broader education regarding guidelines, needs to be addressed.

Heritabilities and genetic correlations for reproductive traits in an F2 reciprocal cross chicken population

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Measurement of the t(t)over-bar production cross section in p(p)over-bar collisions at root s=1.96 TeV

We measure the t (t) over bar production cross section in p (p) over bar collisions at root s = 1.96 TeV in the lepton + jets channel. Two complementary methods discriminate between signal and background: b tagging and a kinematic likelihood discriminant. Based on 0.9 fb(-1) of data collected by the D0 detector at the Fermilab Tevatron Collider, we measure sigma(t (t) over bar) = 7.62 +/- 0.85 pb, assuming the current world average m(t) = 172.6 GeV. We compare our cross section measurement with theory predictions to determine a value for the top-quark mass of 170 +/- 7 GeV.

Measurement of the t̄t production cross section in the all-jet final state in pp collisions at √s=7 TeV

A measurement is presented of the t̄t production cross section σt̄t in proton-proton collisions at a centre-of-mass energy of 7 TeV, in the all-jet final state that contains at least six jets, two of which are tagged as originating from b quarks. The data correspond to an integrated luminosity of 3.54 fb-1, collected with the CMS detector at the LHC. The cross section is determined through an unbinned maximum likelihood fit of background and t̄t signal to the reconstructed mass spectrum of t̄t candidates in the data, in which events are subjected to a kinematic fit assuming a t̄t → W+bW-̄b → 6 jets hypothesis. The measurement yields σt̄t = 139±10(stat.)±26(syst.)±3(lum.)pb, a result consistent with those obtained in other t̄t decay channels, as well as with predictions of the standard model. © 2013 CERN for the benefit of the CMS collaboration.

Fitting of Mixtures with Unspecified Number of Components Using Cross Validation Distance Estimate

Estimation of the number of mixture components (k) is an unsolved problem. Available methods for estimation of k include bootstrapping the likelihood ratio test statistics and optimizing a variety of validity functionals such as AIC, BIC/MDL, and ICOMP. We investigate the minimization of distance between fitted mixture model and the true density as a method for estimating k. The distances considered are Kullback-Leibler (KL) and “L sub 2”. We estimate these distances using cross validation. A reliable estimate of k is obtained by voting of B estimates of k corresponding to B cross validation estimates of distance. This estimation methods with KL distance is very similar to Monte Carlo cross validated likelihood methods discussed by Smyth (2000). With focus on univariate normal mixtures, we present simulation studies that compare the cross validated distance method with AIC, BIC/MDL, and ICOMP. We also apply the cross validation estimate of distance approach along with AIC, BIC/MDL and ICOMP approach, to data from an osteoporosis drug trial in order to find groups that differentially respond to treatment.

Identifying sociodemographic differences in Intimate Partner Violence among immigrant and native women in Spain: a cross-sectional study

Objectives: To analyze whether sociodemographics and social support have a different or similar effect on the likelihood of Intimate Partner Violence in immigrants and natives, and to estimate prevalences and associations between different types of IPV depending on women's birthplace. Methods: Cross-sectional study of 10,048 women (18–70 years) attending primary healthcare in Spain (2006–2007). Outcome: Current Intimate Partner Violence (psychological, physical and both). Sociodemographics and social support were considered first as explicative and later as control variables. Results: Similar Intimate Partner Violence sociodemographic and social support factors were observed among immigrants and natives. However, these associations were stronger among immigrants, except in the case of poor social support (adjusted odds ratio natives 4.36 and adjusted odds ratio immigrants 4.09). When these two groups were compared, immigrants showed a higher likelihood of IPV than natives (adjusted odds ratios 1.58). Conclusion: Immigrant women are in a disadvantaged Intimate Partner Violence situation. It is necessary that interventions take these inequalities into account.

The transform likelihood ratio method for rare event simulation with heavy tails

We present a novel method, called the transform likelihood ratio (TLR) method, for estimation of rare event probabilities with heavy-tailed distributions. Via a simple transformation ( change of variables) technique the TLR method reduces the original rare event probability estimation with heavy tail distributions to an equivalent one with light tail distributions. Once this transformation has been established we estimate the rare event probability via importance sampling, using the classical exponential change of measure or the standard likelihood ratio change of measure. In the latter case the importance sampling distribution is chosen from the same parametric family as the transformed distribution. We estimate the optimal parameter vector of the importance sampling distribution using the cross-entropy method. We prove the polynomial complexity of the TLR method for certain heavy-tailed models and demonstrate numerically its high efficiency for various heavy-tailed models previously thought to be intractable. We also show that the TLR method can be viewed as a universal tool in the sense that not only it provides a unified view for heavy-tailed simulation but also can be efficiently used in simulation with light-tailed distributions. We present extensive simulation results which support the efficiency of the TLR method.

Heavy tails, importance sampling and cross-entropy

We consider the problem of estimating P(Yi + (...) + Y-n > x) by importance sampling when the Yi are i.i.d. and heavy-tailed. The idea is to exploit the cross-entropy method as a toot for choosing good parameters in the importance sampling distribution; in doing so, we use the asymptotic description that given P(Y-1 + (...) + Y-n > x), n - 1 of the Yi have distribution F and one the conditional distribution of Y given Y > x. We show in some specific parametric examples (Pareto and Weibull) how this leads to precise answers which, as demonstrated numerically, are close to being variance minimal within the parametric class under consideration. Related problems for M/G/l and GI/G/l queues are also discussed.

Responses in carcass lean pH at 24 hours post-mortem in lines of Large White pigs selected for growth rate on a fixed ration over a set time

A restricted maximum likelihood analysis applied to an animal model showed no significant differences (P > 0.05) in pH value of the longissimus dorsi measured at 24 h post-mortem (pH24) between high and low lines of Large White pigs selected over 4 years for post-weaning growth rate on restricted feeding. Genetic and phenotypic correlations between pH24 and production and carcass traits were estimated using all performance testing records combined with the pH24 measurements (5.05–7.02) on slaughtered animals. The estimate of heritability for pH24 was moderate (0.29 ± 0.18). Genetic correlations between pH24 and production or carcass composition traits, except for ultrasonic backfat (UBF), were not significantly different from zero. UBF had a moderate, positive genetic correlation with pH24 (0.24 ± 0.33). These estimates of genetic correlations affirmed that selection for increased growth rate on restricted feeding is likely to result in limited changes in pH24 and pork quality since the selection does not put a high emphasis on reduced fatness.

The effect of age, gender and driver status on pedestrians' intentions to cross the road in risky situations

The theory of planned behaviour (TPB) has been used successfully in the past to account for pedestrians' intentions to cross the road in risky situations. However, accident statistics show age and gender differences in the likelihood of adult pedestrian accidents. This study extends earlier work by examining the relative importance of the model components as predictors of intention to cross for four different adult age groups, men, women, drivers and nondrivers. The groups did not differ in the extent to which they differentiated between two situations of varying perceived risk. The model fit was good, but accounted for less of the variance in intention for the youngest group (17-24) than for other age groups. Differences between the age groups in intention to cross seemed to be due to differences in perceived value of crossing rather than differences in perceived risk. Women were less likely to intend to cross than men and perceived more risk, and there were important age, gender and driver status differences in the importance of the TPB variables as predictors of intention. A key implication of these findings is that road safety interventions need to be designed differently for different groups. © 2006 Elsevier Ltd. All rights reserved.