The stellar halo of the Galaxy

Stellar halos may hold some of the best preserved fossils of the formation history of galaxies. They are a natural product of the merging processes that probably take place during the assembly of a galaxy, and hence may well be the most ubiquitous component of galaxies, independently of their Hubble type. This review focuses on our current understanding of the spatial structure, the kinematics and chemistry of halo stars in the Milky Way. In recent years, we have experienced a change in paradigm thanks to the discovery of large amounts of substructure, especially in the outer halo. I discuss the implications of the currently available observational constraints and fold them into several possible formation scenarios. Unraveling the formation of the Galactic halo will be possible in the near future through a combination of large wide field photometric and spectroscopic surveys, and especially in the era of Gaia.Comment: 46 pages, 16 figures. References updated and some minor changes. Full-resolution version available at http://www.astro.rug.nl/~ahelmi/stellar-halo-review.pd

Factors influencing overweight children's commencement of and continuation in a resistance training program

<p>Abstract</p> <p>Background</p> <p>In light of the child overweight and obesity problem in Australia, resistance training programs have been trialled as an innovative way of assisting children increase lean body mass and reduce body fat. The purpose of this study was to investigate the factors influencing overweight children's participation in a resistance training trial program.</p> <p>Method</p> <p>Parent-child pairs who participated in the trial program were invited to take part in a follow-up individual interview to discuss their program experiences. In total, 22 semi-structured interviews were conducted with 11 parent-child pairs.</p> <p>Results</p> <p>The factors found to be most relevant to program commencement among parents were a desire for their child to lose weight and gain confidence, the proximity of the venue, and no cost for participation. For children, the most relevant factors were the opportunity to build strength and improve fitness and having supportive parents who facilitated program initiation. The factors most relevant to continuation for parents were the quality of the program management, being able to stay for the sessions, the child's improved weight status, coordination, and confidence, and no cost for participation. Weight loss and improved confidence were also motivators for continuation among the children, along with pleasant social interaction with peers and trainers and ongoing parental support.</p> <p>Conclusion</p> <p>Different factors variably influence program commencement and program continuation in both parents and children. This has important implications for future interventions that aim to successfully recruit and retain intervention participants.</p

Risk of Severe Knee and Hip Osteoarthritis in Relation to Level of Physical Exercise: A Prospective Cohort Study of Long-Distance Skiers in Sweden

Background: To complete long-distance ski races, regular physical exercise is required. This includes not only cross-country skiing but also endurance exercise during the snow-free seasons. The aim of this study was to determine whether the level of physical exercise is associated with future risk of severe osteoarthritis independent of previous diseases and injuries. Methodology/Principal Findings: We used a cohort that consisted of 48 574 men and 5 409 women who participated in the 90 km ski race Vasaloppet at least once between 1989 and 1998. Number of performed races and finishing time were used as estimates of exercise level. By matching to the National Patient Register we identified participants with severe osteoarthritis, defined as arthroplasty of knee or hip due to osteoarthritis. With an average follow-up of 10 years, we identified 528 men and 42 women with incident osteoarthritis. The crude rate was 1.1/1000 person-years for men and 0.8/1000 person-years for women. Compared with racing once, participation in &gt;= 5 races was associated with a 70% higher rate of osteoarthritis (multivariable-adjusted hazard ratio (HR) 1.72, 95% confidence interval (CI) 1.33 to 2.22). The association was dose-dependent with an adjusted HR of 1.09, 95% CI 1.05 to 1.13 for each completed race. A faster finishing time, in comparison with a slow finishing time, was also associated with an increased rate (adjusted HR 1.51, 95% CI 1.14 to 2.01). Contrasting those with 5 or more ski races and a fast finish time to those who only participated once with a slow finish time, the adjusted HR of osteoarthritis was 2.73, 95% CI 1.78 to 4.18. Conclusions/Significance: Participants with multiple and fast races have an increased risk of subsequent arthroplasty of knee and hip due to osteoarthritis, suggesting that intensive exercise may increase the risk

Geographical information system and environmental epidemiology: a cross-sectional spatial analysis of the effects of traffic-related air pollution on population respiratory health

<p>Abstract</p> <p>Background</p> <p>Traffic-related air pollution is a potential risk factor for human respiratory health. A Geographical Information System (GIS) approach was used to examine whether distance from a main road (the Tosco-Romagnola road) affected respiratory health status.</p> <p>Methods</p> <p>We used data collected during an epidemiological survey performed in the Pisa-Cascina area (central Italy) in the period 1991-93. A total of 2841 subjects participated in the survey and filled out a standardized questionnaire on health status, socio-demographic information, and personal habits. A variable proportion of subjects performed lung function and allergy tests. Highly exposed subjects were defined as those living within 100 m of the main road, moderately exposed as those living between 100 and 250 m from the road, and unexposed as those living between 250 and 800 m from the road. Statistical analyses were conducted to compare the risks for respiratory symptoms and diseases between exposed and unexposed. All analyses were stratified by gender.</p> <p>Results</p> <p>The study comprised 2062 subjects: mean age was 45.9 years for men and 48.9 years for women. Compared to subjects living between 250 m and 800 m from the main road, subjects living within 100 m of the main road had increased adjusted risks for persistent wheeze (OR = 1.76, 95% CI = 1.08-2.87), COPD diagnosis (OR = 1.80, 95% CI = 1.03-3.08), and reduced FEV₁/FVC ratio (OR = 2.07, 95% CI = 1.11-3.87) among males, and for dyspnea (OR = 1.61, 95% CI = 1.13-2.27), positivity to skin prick test (OR = 1.83, 95% CI = 1.11-3.00), asthma diagnosis (OR = 1.68, 95% CI = 0.97-2.88) and attacks of shortness of breath with wheeze (OR = 1.67, 95% CI = 0.98-2.84) among females.</p> <p>Conclusion</p> <p>This study points out the potential effects of traffic-related air pollution on respiratory health status, including lung function impairment. It also highlights the added value of GIS in environmental health research.</p

Spatial analysis of air pollution and childhood asthma in Hamilton, Canada: comparing exposure methods in sensitive subgroups

<p>Abstract</p> <p>Background</p> <p>Variations in air pollution exposure within a community may be associated with asthma prevalence. However, studies conducted to date have produced inconsistent results, possibly due to errors in measurement of the exposures.</p> <p>Methods</p> <p>A standardized asthma survey was administered to children in grades one and eight in Hamilton, Canada, in 1994–95 (N ~1467). Exposure to air pollution was estimated in four ways: (1) distance from roadways; (2) interpolated surfaces for ozone, sulfur dioxide, particulate matter and nitrous oxides from seven to nine governmental monitoring stations; (3) a kriged nitrogen dioxide (NO₂) surface based on a network of 100 passive NO₂monitors; and (4) a land use regression (LUR) model derived from the same monitoring network. Logistic regressions were used to test associations between asthma and air pollution, controlling for variables including neighbourhood income, dwelling value, state of housing, a deprivation index and smoking.</p> <p>Results</p> <p>There were no significant associations between any of the exposure estimates and asthma in the whole population, but large effects were detected the subgroup of children without hayfever (predominately in girls). The most robust effects were observed for the association of asthma without hayfever and NO₂LUR OR = 1.86 (95%CI, 1.59–2.16) in all girls and OR = 2.98 (95%CI, 0.98–9.06) for older girls, over an interquartile range increase and controlling for confounders.</p> <p>Conclusion</p> <p>Our findings indicate that traffic-related pollutants, such as NO₂, are associated with asthma without overt evidence of other atopic disorders among female children living in a medium-sized Canadian city. The effects were sensitive to the method of exposure estimation. More refined exposure models produced the most robust associations.</p

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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Evaluation of appendicitis risk prediction models in adults with suspected appendicitis

Background Appendicitis is the most common general surgical emergency worldwide, but its diagnosis remains challenging. The aim of this study was to determine whether existing risk prediction models can reliably identify patients presenting to hospital in the UK with acute right iliac fossa (RIF) pain who are at low risk of appendicitis. Methods A systematic search was completed to identify all existing appendicitis risk prediction models. Models were validated using UK data from an international prospective cohort study that captured consecutive patients aged 16–45 years presenting to hospital with acute RIF in March to June 2017. The main outcome was best achievable model specificity (proportion of patients who did not have appendicitis correctly classified as low risk) whilst maintaining a failure rate below 5 per cent (proportion of patients identified as low risk who actually had appendicitis). Results Some 5345 patients across 154 UK hospitals were identified, of which two‐thirds (3613 of 5345, 67·6 per cent) were women. Women were more than twice as likely to undergo surgery with removal of a histologically normal appendix (272 of 964, 28·2 per cent) than men (120 of 993, 12·1 per cent) (relative risk 2·33, 95 per cent c.i. 1·92 to 2·84; P < 0·001). Of 15 validated risk prediction models, the Adult Appendicitis Score performed best (cut‐off score 8 or less, specificity 63·1 per cent, failure rate 3·7 per cent). The Appendicitis Inflammatory Response Score performed best for men (cut‐off score 2 or less, specificity 24·7 per cent, failure rate 2·4 per cent). Conclusion Women in the UK had a disproportionate risk of admission without surgical intervention and had high rates of normal appendicectomy. Risk prediction models to support shared decision‐making by identifying adults in the UK at low risk of appendicitis were identified