Does relative age distribution influence the physical and anthropometric profiles of drafted under 18 Australian footballers? An Investigation between the 2010 to 2013 seasons

This study examined if the relative birth distribution of drafted under 18 (U18) Australian football (AF) players influenced their physical and anthropometric profile. Birthdate, physical (vertical jump, agility, 20m sprint, 20m multistage fitness test) and anthropometric (standing height, body mass) data were obtained from U18 players drafted into the Australian Football League between 2010 to 2013 (n = 212). Birth distribution did not change across quartile (χ23 = 5.09, P > 0.05) or half year (χ21= 2.50, P > 0.05). Physical and anthropometric profiles did not differ according to quartile or half year (P > 0.05). Relative birth distribution did not appear to influence draft success or physical/anthropometric profile. This study provides insight into a phenomenon not always observed in team sport.

Do Red Knots (Calidris Canutus Islandica) routinely skip Iceland during southward migration?

Subspecies Calidris canutus islandica of the Red Knot breeds on the arctic tundra of northeastern Canada and northern Greenland and winters along the coasts of northwestern Europe. During northward migration, it stops over in either Iceland or northern Norway. It has been assumed that it does the same during southward migration. Using ratios of stable carbon isotopes (δ ¹³ C) in whole blood, blood cells, and plasma, we investigated evidence for a stopover in Iceland en route from the breeding grounds to the Dutch Wadden Sea. With the expected diet (shellfish) and stopover duration at Iceland (12-15 days, maximum 17 days) and the turnover rates of blood cells (15.1 days) and plasma (6.0 days), Red Knots that stopped in Iceland should arrive with a blood (cell) δ ¹³ C midway between a tundra (-24.7[per thousand]) and a marine value (-14.0[per thousand]) and a plasma δ¹³ C approaching the marine value (-15.3[per thousand]). However, many adults arriving at the Wadden Sea had δ¹³ C ratios in blood (cells) and plasma below these levels, and some arrived with clear tundra signals in blood cells, suggesting that they skipped Iceland during southward migration. Surprisingly, available data suggest this also to be true for juveniles during their first southward migration. The δ ¹³ C signature of second-year birds confirmed that they oversummered in the Wadden Sea. Our findings contradict the largely untested idea that juvenile shorebirds make more stopovers than adults as well as the idea that the migration between the Nearctic and Europe is necessarily a two-leg process.

The population cost-effectiveness of delivering universal and indicated school-based interventions to prevent the onset of major depression among youth in Australia

AIMS: School-based psychological interventions encompass: universal interventions targeting youth in the general population; and indicated interventions targeting youth with subthreshold depression. This study aimed to: (1) examine the population cost-effectiveness of delivering universal and indicated prevention interventions to youth in the population aged 11-17 years via primary and secondary schools in Australia; and (2) compare the comparative cost-effectiveness of delivering these interventions using face-to-face and internet-based delivery mechanisms. METHODS: We reviewed literature on the prevention of depression to identify all interventions targeting youth that would be suitable for implementation in Australia and had evidence of efficacy to support analysis. From this, we found evidence of effectiveness for the following intervention types: universal prevention involving group-based psychological interventions delivered to all participating school students; and indicated prevention involving group-based psychological interventions delivered to students with subthreshold depression. We constructed a Markov model to assess the cost-effectiveness of delivering universal and indicated interventions in the population relative to a 'no intervention' comparator over a 10-year time horizon. A disease model was used to simulate epidemiological transitions between three health states (i.e., healthy, diseased and dead). Intervention effect sizes were based on meta-analyses of randomised control trial data identified in the aforementioned review; while health benefits were measured as Disability-adjusted Life Years (DALYs) averted attributable to reductions in depression incidence. Net costs of delivering interventions were calculated using relevant Australian data. Uncertainty and sensitivity analyses were conducted to test model assumptions. Incremental cost-effectiveness ratios (ICERs) were measured in 2013 Australian dollars per DALY averted; with costs and benefits discounted at 3%. RESULTS: Universal and indicated psychological interventions delivered through face-to-face modalities had ICERs below a threshold of $50 000 per DALY averted. That is, $7350 per DALY averted (95% uncertainty interval (UI): dominates - 23 070) for universal prevention, and $19 550 per DALY averted (95% UI: 3081-56 713) for indicated prevention. Baseline ICERs were generally robust to changes in model assumptions. We conducted a sensitivity analysis which found that internet-delivered prevention interventions were highly cost-effective when assuming intervention effect sizes of 100 and 50% relative to effect sizes observed for face-to-face delivered interventions. These results should, however, be interpreted with caution due to the paucity of data. CONCLUSIONS: School-based psychological interventions appear to be cost-effective. However, realising efficiency gains in the population is ultimately dependent on ensuring successful system-level implementation.

Effect of 2 weeks of endurance training on uncoupling protein3 content in untrained human subjects

Aim: The mitochondrial uncoupling protein-3 (UCP3) is able to lower the proton gradient across the inner mitochondrial membrane, thereby uncoupling substrate oxidation from ATP production and dissipating energy as heat. What the effect of endurance training on UCP3 is, is still  controversial. Endurance-trained athletes are characterized by lower levels of UCP3, but longitudinal studies in rodents reported no effect of endurance training on muscular UCP3 levels. Here, we examined the effect of a 2-week training programme on skeletal muscle UCP3 protein content in untrained human subjects, and hypothesized that UCP3 will be reduced after the training programme. Methods: Nine untrained men [age: 23.3±3.2 years; BMI: 22.6±2.6 kg m^-2; maximal power output (^Wmax): 3.8±0.6 W kg^-1 body weight] trained for 2 weeks. Before and at least 72 h after the training period, muscle biopsies were taken for determination of UCP3 protein content. Results: UCP3 protein content tended to be lower after the training programme [95±10 vs. 109±12 arbitrary units (AU), P= 0.08]. Cytochrome c content tended to increase with 33% in response to endurance training (52± 6 vs. 39± 6 AU, P = 0.08). The ratio UCP3 relative to cytochrome c tended to decrease significantly upon endurance training (2.0±0.4 vs. 3.2±0.6 AU, P = 0.01). Conclusion: A short-term (2-week) endurance training programme decreased UCP3 protein levels and significantly reduced the ratio of UCP3 to cytochrome c.

Overweight children have poor bone strength relative to body weight, placing them at greater risk for forearm fractures

Introduction: Obesity is thought to be a protective factor for bones in adults but not in children based on the evidence of the greater incidence of forearm fractures in obese children. Our objective was to investigate the effect of adiposity on bone strength in relation to the mechanical challenge placed onto the forearm bones in case of a fall.

Methods: Cross sectional areas (CSA) were obtained at the mid- and distal radius by peripheral quantitative computed tomography in 486 children (241 boys), mean age 8.3 years (range 6.9–9.7), participating in the LOOK Project. The following parameters were measured: bone mass and bone CSA (both sites), and muscle and fat CSA (mid-forearm only). Bone strength indices combining bone size and total volumetric density were calculated at each site.

Results/Discussion: Overweight children (BMI > percentile equivalent to 25 kg/m² in adults) have higher bone parameters than normal-weight peers (Z-scores +0.6 to +0.9SD, p < 0.0001). These differences disappear after adjustment for muscle CSA. Adiposity (fat CSA/muscle CSA) was negatively correlated with bone mass, size and strength at the distal radius only (r = −0.1, p < 0.05). After adjustment for body weight (estimate of the load during a fall), the negative correlations were stronger and observed at both the mid- and distal radius (r = −0.37 to −0.55, p < 0.0001).

Conclusion. Overweight children have stronger bones due to greater muscle size. However, children with high fat mass relative to muscle mass (increased adiposity) have poorer bone strength, independent of weight, which may contribute to the increased risk of fracture in obese children.

Absolute versus relative difference measures of priming: Which is appropriate when baseline scores change with age?

It is often of theoretical interest to know if implicit memory (repetition priming) develops across childhood under a given circumstance. Methodologically, however, it is difficult to determine whether development is present when baseline performance for unstudied items improves with age. Calculation of priming in absolute (priming=studied - unstudied) or relative-to-baseline terms can lead to different conclusions. In first noting this problem, Parkin (1993) suggested using the Snodgrass (1989a) calculation of relative priming [priming=(studied - unstudied)/(maximum - unstudied)], and most developmental studies have since adopted this procedure. Here, we question the Snodgrass method because the Snodgrass method's results are not replicated in the picture identification task when baselines are equated experimentally across age groups. Instead, results support an absolute measure of priming. Theoretically, we argue against its core assumption; namely, that children and adults always lie on the same learning curve, with an equal maximum performance level and equal rate of learning.

Effect of Jersey type on thermoregulatory responses during exercise in a warm humid environment

The thermoregulatory responses of subjects wearing two different forms of rugby league jersey, one with plastic sponsorship recognition and numbering (trial Gl) and one without (trial G2), and a lightweight alternative (trial G3), were compared with a trial without any form of upper body garment (trial GO). Ten male volunteers, mean age 20.9 (±2.3) years, height 179.8 (±4.7) cm, weight 80.2 (±8.9) kg, and body surface area 1.99 (±0.13) m2, participated in this study. Subjects had a mean maximal oxygen uptake capacity of 56.0 (±6.3) ml.kg.min-1 and a sum of 8 skinfolds of 80.6 (±23.8) mm. Subjects were exercised at approximately 50% of maximal oxygen uptake in a warm humid environment for 50 minutes. Mean ambient temperature was 27.6°C (±0.32) with a relative humidity of 64.7% (±1.44). Measurements of core and skin (7 sites) temperature, heart rate, oxygen uptake, plasma volume, peak lactate concentration, and pre- and post-trial body weight, hematocrit and garment weight were recorded. The statistical results showed that all subjects experienced significant (p ≤.0001) decreases in body weight representing a percentage decrease ranging from 1.2-1.3%. No significant difference was found between trials with respect to body weight change. No significant effect of garment type was found on pre- and post-trial hematocrit, plasma volume changes or peak blood lactic acid concentration. However, mean peak lactate was highest for trial Gl (5.6 mmol.L-1 ±2.2) and lowest for trial G3 (4.6 mmol.L-1 ±1.27). Post-trial core temperature was significantly (p≤ .0001) higher than the resting value; no significant difference was found between trials. The mean absolute increase for all experimental trials was 0.9°C. A significant (p≤.005) difference between mean total (7 sites) skin temperature was found with a post-hoc test revealing that trials Gl and G2 were significantly higher than trial GO; no significant difference was found when comparing trial G3 with trial GO or when comparing the garments between each other. Mean skin temperature under the garment (4 sites) was found to be significantly (p≤.05) higher for all trials involving a garment when compared with mean skin temperature outside (3 sites) the garment; no significant difference was found between trials. Mean oxygen uptake was significantly different between trials (p≤.005), with trial Gl and G3 found to be significantly lower than trial GO; no difference was found when comparing the garments with each other. Post-trial garment weights were significantly (p≤.001) heavier than pre-trial and were significantly (p≤.0001) different when compared with each other. There was no significant effect on heart rate, haematocrit, plasma volume changes, peak blood lactic acid concentration, or core temperature due to garment type. However, differences in skin temperature suggest that the garment used in trial G3 may have a benefit. Further research should consider the impact of increased exercise intensity and/or environmental temperature and humidity on the measured parameters while wearing the garments described in this study.

Prediction of children's flavour preferences. Effect of age and stability in reported preferences

The present study investigated whether children were able to communicate stable flavour preferences and whether mothers’ ability to correctly identify their child's flavour preferences is related to the stability of their child's flavour preferences. On 2 consecutive days, 75 girls and 77 boys (3–10 years, mean age = 7.1 ± 2.3 years) carried out a preference ranking task for five ice-cream flavours: mint, coffee, chocolate and two variants of vanilla. Without input from their child, mothers ranked four of these flavours according to their own understanding of their child's flavour preferences. Spearman rank order correlations suggest that older aged children (5–10 years) have more stable flavour preferences than younger aged children (3–5 years) (p < 0.05). Only 39% of mothers were able to correctly predict children's most preferred flavour, but significantly more parents (61%) were able to predict children's least preferred flavour (p < 0.05). Mothers’ ability to correctly predict their children's least preferred flavour seemed to be facilitated by children's ability to communicate their least preferred flavours in a consistent manner (p < 0.05). It is recommended to apply proper sensory methodologies with children rather than relying on mothers’ report when interested in children's likes. When interested in children's dislikes mothers’ report might be suitable.

Effect of diet, sex and age on fatty acid metabolism in broiler chickens : SFA and MUFA

The present study was conducted to evaluate the effect of different dietary lipid sources, age and sex on the SFA and MUFA metabolism in broiler chickens using a whole body fatty acid balance method. Four dietary lipid sources (palm fat, Palm; soyabean oil, Soya; linseed oil, Lin; and fish oil, Fish) were added at 3% to a basal diet containing 5% Palm. Diets were fed to female and male chickens from day 1 to either day 21 or day 42 of age. The accumulation (percentage of net intake and ex novo production) of SFA and MUFA was significantly lower in broilers fed on Palm than in broilers fed on the other diets (85·7 v. 97·4 %). Conversely, β-oxidation was significantly higher in Palm-fed birds than the average of the other dietary treatments (14·3 v. 2·6 %). On average, 33·1% of total SFA and MUFA accumulated in the body were elongated, and 13·8% were Δ-9 desaturated to longer chain or more unsaturated metabolites, with lower proportions being elongated and desaturated for the Palm and Fish diets than for the Soya and Lin diets. Total in vivo apparent elongase activity decreased exponentially in relation to the net intake of SFA and MUFA, while it increased with age. Total in vivo apparent Δ-9 desaturase activity was not significantly affected by dietary treatment or age. Total ex novo production and β-oxidation of SFA and MUFA showed a negative and positive curvilinear relationship with net intake of SFA and MUFA, respectively. Sex had no effect on SFA and MUFA metabolism.

Effect of diet, sex and age on fatty acid metabolism in broiler chickens : n-3 and n-6 PUFA

The PUFA metabolism in broiler chicken was studied through the whole body fatty acid balance method. Four dietary lipid sources (palm fat, Palm; soyabean oil, Soya; linseed oil, Lin; fish oil, Fish) were added at 3% to a basal diet containing 5% palm fat. Diets were fed to female and male birds from day 1 to either day 21 or day 42 of age. Birds fed the Lin diet showed a significantly higher 18 : 2n-6 accumulation compared with the other diets (85·2 v. 73·6% of net intake), whereas diet did not affect 18 : 3n-3 accumulation (mean 63% of net intake). Bioconversion of 18 : 2n-6 significantly decreased in the order Palm.> Lin > Soya > Fish (4·7, 3·9, 3·4 and 1% of net intake, respectively). The 18 : 3n-3 bioconversion on the Palm and Soya diets was similar and significantly higher than in broilers on the Lin diet (9·1 v. 5·8% of net intake). The β-oxidation of 18 : 2n-6 was significantly lower on the Lin diet than on the other diets (10·8 v. 23·3% of net intake), whereasβ-oxidation of 18 : 3n-3 was significantly higher on the Fish diet than on the other diets (41·5 v. 27·3% of net intake). Feeding fish oil suppressed apparent elongase and desaturase activity, whereas a higher dietary supply of 18 : 3n-3 and 18 : 2n-6 enhanced apparent elongation and desaturation activity on the PUFA involved in the n-3 and n-6 pathway, respectively. Accumulation of 18 : 2n-6 and 18 : 3n-3 increased andβ -oxidation decreased with age. Sex had a marginal effect on the PUFA metabolism.

The role of testosterone in bib size determination in the male house sparrow Passer domesticus, is age dependent

Secondary sexual signals are thought to indicate individual quality. In order to understand the evolutionary pressures that give rise to such traits it is important to understand the physiological mechanisms underlying their production. The black bib of the house sparrow Passer domesticus is known to function as a badge of social status in males. Past studies have found that the size of the bib in older males is determined, at least partly, by the androgen testosterone. The immunocompetence handicap hypothesis suggests that testosterone has a key role in maintaining honest signalling – it is both involved in the development or expression of sexual signals and is immunosuppressive. In this paper we test experimentally two hypo theses relating to bib size development, whether 1) testosterone is only immunosuppressive in conditions where the natural feedback loop from the testes has been removed, and 2) testosterone is, in addition to influencing the bib size of older males, responsible for the size of the bib in juvenile sparrows. In the first experiment we found that exogenous testosterone administered to intact males during the winter (when LH and FSH levels are very low and were not artificially increased by castration) caused significant immunosuppression, albeit in interaction with the stress hormone corticosterone. Second, we found that exogenous testosterone administration in castrated fledgling male house sparrows had no effect on subsequent post-juvenile moult bib size relative to controls. Our results suggest that in some circumstances testosterone can be immunosuppressive, but that its role in bib size determination is age-dependent.

A clustered randomised trial examining the effect of social marketing and community mobilisation on the age of uptake and levels of alcohol consumption by Australian adolescents

Introduction
Throughout the world, alcohol consumption is common among adolescents. Adolescent alcohol use and misuse have prognostic significance for several adverse long-term outcomes, including alcohol problems, alcohol dependence, school disengagement and illicit drug use. The aim of this study was to evaluate whether randomisation to a community mobilisation and social marketing intervention reduces the proportion of adolescents who initiate alcohol use before the Australian legal age of 18, and the frequency and amount of underage adolescent alcohol consumption.
Method and analysis
The study comprises 14 communities matched with 14 non-contiguous communities on socioeconomic status (SES), location and size. One of each pair was randomly allocated to the intervention. Baseline levels of adolescent alcohol use were estimated through school surveys initiated in 2006 (N=8500). Community mobilisation and social marketing interventions were initiated in 2011 to reduce underage alcohol supply and demand. The setting is communities in three Australian states (Victoria, Queensland and Western Australia). Students (N=2576) will complete school surveys in year 8 in 2013 (average age 12). Primary outcomes: (1) lifetime initiation and (2) monthly frequency of alcohol use. Reports of social marketing and family and community alcohol supply sources will also be assessed. Point estimates with 95% CIs will be compared for student alcohol use in intervention and control communities. Changes from 2006 to 2013 will be examined; multilevel modelling will assess whether random assignment of communities to the intervention reduced 2013 alcohol use, after accounting for community level differences. Analyses will also assess whether exposure to social marketing activities increased the intervention target of reducing alcohol supply by parents and community members.