A prospective examination of children's time spent outdoors, objectively measured physical activity and overweight

Objective: This study aimed to determine whether time spent outdoors was associated with objectively measured physical activity, body mass index (BMI) z-score and overweight in elementary-school aged children, cross-sectionally and prospectively over 3 years.
Methods: Three-year cohort study with data collected during 2001 and 2004. Nineteen randomly selected state elementary schools across Melbourne, Australia. One hundred and eighty eight 5–6-year-old and 360 10–12-year-old children. Baseline parent reports of children’s time spent outdoors during warmer and cooler months, on weekdays and weekends. At baseline and follow-up, children’s moderate and vigorous physical activity (MVPA) was objectively assessed by accelerometry, and BMI zscore and overweight was calculated from measured height and weight.
Results: Cross-sectionally, each additional hour outdoors on weekdays and weekend days during the cooler months was associated with an extra 27 min week^-1 MVPA among older girls, and with an extra 20 min week^-1 MVPA among older boys. Longitudinally, more time outdoors on weekends predicted higher MVPA on weekends among older girls and boys (5 min week^-1). The prevalence of overweight among older children at follow-up was 27–41% lower among those spending more time outdoors at baseline.
Conclusion: Encouraging 10–12-year-old children to spend more time outdoors may be an effective strategy for increasing physical activity and preventing increases in overweight and obesity. Intervention research investigating the effect of increasing time outdoors on children’s physical activity and overweight is warranted.

Decorin is a secreted protein associated with obesity and type 2 diabetes

Psammomys obesus

The division of labor, capital, communication technology and economic growth : the case of China 1952–99

The implications of the division of labor, capital, and technology for economic growth have long been a fundamental issue in development economics. This paper employs the bounds testing approach to cointegration to examine the relationship between the division of labor, capital accumulation, communication technology, and economic growth for China over the period 1952–99. We find that in the long run, capital stock and the division of labor both have statistically significant positive effects on growth, while in the short run the effects are not significantly positive. Telecommunication technology, rather surprisingly, has a statistically insignificant impact on growth both in the long run and in the short run. Our findings indicate that there exists a long run equilibrium relationship between capital and the division of labor on the one hand, and economic growth on the other, thereby lending support to the division of labor theory of growth.

Dietary combination of soy with a probiotic or prebiotic food significantly reduces total and LDL cholesterol in mildly hypercholesterolaemic subjects

Objective: We hypothesized that a dietary combination of soy with either a probiotic (yoghurt) or a prebiotic (resistant starch) would result in enhanced lipid-lowering effects compared with a control soy diet, possibly via improvements in isoflavone bioavailability.

Subjects: Mildly hypercholesterolaemic subjects (men and post-menopausal women) older than 45 years were recruited via the local media. Thirty-six subjects commenced the study; five withdrew.

Results: Soy+probiotic significantly decreased total cholesterol (4.72.0%; P=0.038) and soy+prebiotic significantly decreased total and low-density lipoprotein cholesterol (5.51.6%; P=0.003 and 7.32.2%; P=0.005, respectively). The bioavailabilities of daidzein, genistein or equol were not affected by probiotic or prebiotic consumption or associated with lipid changes.

Conclusion: Dietary combination of soy with either a probiotic or a prebiotic resulted in significant lipid lowering, not related to isoflavone bioavailability.

Identification of secreted proteins associated with obesity and type 2 diabetes in Psammomys obesus

Objective: Skeletal muscle produces a variety of secreted proteins that have important roles in intercellular communication and affects processes such as glucose homoeostasis. The objective of this study was to develop a novel Signal Sequence Trap (SST) in conjunction with cDNA microarray technology to identify proteins secreted from skeletal muscle of Psammomys obesus that were associated with obesity and type 2 diabetes (T2D).

Design: Secreted proteins that were differentially expressed between lean, normal glucose tolerant (NGT), overweight and impaired glucose tolerant (IGT) and obese, T2D P. obesus were isolated using SST in conjunction with cDNA microarray technology. Subsequent gene expression was measured in tissues from P. obesus by real-time PCR (RT-PCR).

Results: The SST yielded 1600 positive clones, which were screened for differential expression. A total of 91 (B6%) clones were identified by microarray to be differentially expressed between NGT, IGT and T2D P. obesus. These clones were sequenced to identify 51 genes, of which only 27 were previously known to encode secreted proteins. Three candidate genes not previously associated with obesity or type 2 diabetes, sushi domain containing 2, collagen and calcium-binding EGF domains 1 and periostin (Postn), as well as one gene known to be associated, complement component 1, were shown by RT-PCR to be differentially expressed in  skeletal muscle of P. obesus. Further characterization of the secreted protein Postn revealed it to be predominantly expressed in adipose tissue, with higher expression in visceral compared with subcutaneous adipose depots.

Conclusion: SST in conjunction with cDNA microarray technology is a powerful tool to identify differentially expressed secreted proteins involved in complex diseases such as obesity and type 2 diabetes. Furthermore, a number of candidate genes were identified, in particular, Postn, which may have a role in the development of obesity and type 2 diabetes.

Is there global inclusion in publishing in the five leading advertising journals and does this relate to general publishing performance : a regional comparison

The question has been raised in academia whether there is global inclusion of authors in publishing. This has generally not been explored in the 30 years of research on advertising research activity and those works that do exist in advertising have generally only examined three North American focused journals. This paper expands the set of journals to five advertising focused journals and thus is a global examination of publishing in advertising. Within these five advertising journals there is an increased international involvement and thus it appears that a broader set of perspectives are being considered in the advertising literature. We also found that there is a positive correlation between publishing in the five leading advertising journals and four leading generalist journals, suggesting that institutions may be developing broader research cultures, rather than targeting works only in advertising.

The cost-effectiveness of removing television advertising of high-fat and/or high-sugar food and beverages to Australian children

Objective: To model the health benefits and cost-effectiveness of banning television (TV) advertisements in Australia for energy-dense, nutrient-poor food and beverages during children's peak viewing times.

Methods: Benefits were modelled as changes in body mass index (BMI) and disability-adjusted life years (DALYs) saved. Intervention costs (AUD$) were compared with future health-care cost offsets from reduced prevalence of obesity-related health conditions. Changes in BMI were assumed to be maintained through to adulthood. The comparator was current practice, the reference year was 2001, and the discount rate for costs and benefits was 3%. The impact of the withdrawal of non-core food and beverage advertisements on children's actual food consumption was drawn from the best available evidence (a randomized controlled trial of advertisement exposure and food consumption). Supporting evidence was found in ecological relationships between TV advertising and childhood obesity, and from the effects of marketing bans on other products. A Working Group of stakeholders provided input into decisions surrounding the modelling assumptions and second-stage filters of 'strength of evidence', 'equity', 'acceptability to stakeholders', 'feasibility of implementation', 'sustainability' and 'side-effects'.

Results: The intervention had a gross incremental cost-effectiveness ratio of AUD$ 3.70 (95% uncertainty interval (UI) $2.40, $7.70) per DALY. Total DALYs saved were 37 000 (95% UI 16 000, 59 000). When the present value of potential savings in future health-care costs was considered (AUD$ 300m (95% UI $130m, $480m), the intervention was 'dominant', because it resulted in both a health gain and a cost offset compared with current practice.

Conclusions: Although recognizing the limitations of the available evidence, restricting TV food advertising to children would be one of the most cost-effective population-based interventions available to governments today. Despite its economic credentials from a public health perspective, the initiative is strongly opposed by food and advertising industries and is under review by the current Australian government.

Effect of the glycemic index of carbohydrates on day-long (10 h) profiles of plasma glucose, insulin, cholecystokinin and ghrelin

Background: Low glycemic index (GI) carbohydrates have been linked to increased satiety. The drive to eat may be mediated by postprandial changes in glucose, insulin and gut peptides.
Objective: To investigate the effect of a low and a high GI diet on day-long (10 h) blood concentrations of glucose, insulin, cholecystokinin (CCK) and ghrelin (GHR).
Design: Subjects (n¼12) consumed a high and a low GI diet in a randomized, crossover design, consisting of four meals that were matched for macronutrients and fibre, and differed only in carbohydrate quality (GI). Blood was sampled every 30–60 min and assayed for glucose, insulin, CCK and GHR.
Results: The high GI diet resulted in significantly higher glucose and insulin mean incremental areas under the curve (IAUC, P¼0.027 and P¼0.001 respectively). CCK concentration was 59% higher during the first 7 h of the low GI diet (394±95 pmol/l min) vs the high GI diet (163±38 pmol/l min, P¼0.046), but there was no difference over 10 h (P¼0.224). GHR concentration was inversely correlated with insulin concentration (Pearson correlation 0.48, P¼0.007), but did not differ significantly between the low and high GI diets.
Conclusions: Mixed meals of lower GI are associated with lower day-long concentrations of glucose and insulin, and higher CCK after breakfast, morning tea and lunch. This metabolic profile could mediate differences in satiety and hunger seen in some, but not all, studies.

Higher leptin levels in Asian Indians than Creoles and Europids : a potential explanation for increased metabolic risk

Background and purpose: Leptin predicts cardiovascular diseases and type 2 diabetes, diseases to which Asian Indians are highly susceptible. As a risk marker, leptin’s intra-individual and seasonal stability is unstudied and only small studies have compared leptin levels in Asian Indians with other populations. The aim of this study was to explore ethnicity related differences in leptin levels and its intra-individual and seasonal stability.

Methods: Leptin and anthropometric data from the northern Sweden MONICA (3513 Europids) and the Mauritius Non-communicable Disease (2480 Asian Indians and Creoles) studies were used. In both studies men and women, 25- to 74-year old, participated in both an initial population survey and a follow-up after 5–13 years. For the analysis of seasonal leptin variation, a subset of 1780 participants, 30- to 60-year old, in the Vasterbotten Intervention Project was used.

Results: Asian Indian men and women had higher levels of leptin, leptin per body mass index (BMI) unit (leptin/BMI) or per cm in waist circumference (WC; leptin/waist) than Creoles and Europids when adjusted for BMI (all P<0.0005) or WC (all P<0.005). In men, Creoles had higher leptin, leptin/BMI and leptin/waist than Europids when adjusted for BMI or WC (all P<0.0005). In women, Creoles had higher leptin/BMI and leptin/waist than Europids only when adjusted for WC (P<0.0005). Asian Indian ethnicity in both sexes, and Creole ethnicity in men, was independently associated with high leptin levels. The intra-class correlation for leptin was similar (0.6–0.7), independently of sex, ethnicity or follow-up time. No seasonal variation in leptin levels was seen.

Conclusion: Asian Indians have higher levels of leptin, leptin/BMI and leptin/waist than Creoles and Europids. Leptin has a high intra-individual stability and seasonal leptin variation does not appear to explain the ethnic differences observed here.

Sperm competition and offspring viability at hybridization in Australian tree frogs, Litoria peronii and L. tyleri

Hybridization between closely related species often leads to reduced viability or fertility of offspring. Complete failure of hybrid offspring (post-zygotic hybrid incompatibilities) may have an important role in maintaining the integrity of reproductive barriers between closely related species. We show elsewhere that in Peron's tree frog, Litoria peronii, males more closely related to a female sire more offspring in sperm competition with a less related rival male. Observations of rare 'phenotypic intermediate' males between L. peronii and the closely related L. tyleri made us suggest that these relatedness effects on siring success may be because of selection arising from risks of costly hybridization between the two species. Here, we test this hypothesis in an extensive sperm competition experiment, which shows that there is no effect of species identity on probability of fertilization in sperm competition trials controlling for sperm concentration and sperm viability. Instead, there was a close agreement between a male's siring success in isolation with a female and his siring success with the same female in competition with a rival male regardless of species identity. Offspring viability and survival, however, were strongly influenced by species identity. Over a 14-day period, hybrid offspring suffered increasing mortality and developed more malformations and an obvious inability to swim and right themselves, leading to compromised probability of survival. Thus, hybridization in these sympatric tree frogs does not compromise fertilization but has a strong impact on offspring viability and opportunity for reinforcement selection on mate choice for conspecific partners.

Physical activity beliefs and behaviours among adults attempting weight control

Objective: To compare the frequency and duration of varying intensities of physical activity performed by adults trying to lose weight, avoid gaining weight and not actively trying to control their weight, and to compare these groups' beliefs about the physical activity they should perform.

Method: Random postal survey of 2500 Victorian adults selected from the Australian electoral roll (response rate=42%).

Measures: One-week physical activity recall (frequency and duration of walking, other moderate activity and vigorous activity), BMI (based on self-reported height and weight) and weight-control behaviour.

Results: At the time of the survey, 27% of respondents were actively trying to avoid gaining weight, 23.9% trying to lose weight and 49.1% undertaking no weight control. Respondents spent a mean time of 4.0 (±7.1) h walking, 5.5 (±7.9) h in moderate activity and 3.1(±5.9) h in vigorous activity during the week prior to the survey. Women trying to lose weight or avoid gaining weight engaged in vigorous activity more often than women not trying to control their weight. After adjusting for age, education and BMI, women trying to avoid gaining weight were 2.4 times more likely, and women trying to lose weight 2.5 times more likely, to have met current physical activity guidelines than women undertaking no weight control. On average, respondents believed they should spend 5.2 (±6.9) h walking, 6.5 (±8.2) h in moderate activity and 4.3 (±6.5) h in vigorous activity each week. Women trying to lose weight felt they should perform vigorous activity more often than other women. Weight-control behaviour was not associated with physical activity beliefs and behaviours of men.

Conclusion: Walking is a common activity among adults attempting weight control. However, many men and women do not fully recognize the value of moderate-intensity physical activity. Future efforts should be directed at promoting the role of moderate-intensity activity in weight control, particularly activity that can be performed outside of planned activity sessions.

Ethics, entrepreneurship and the adoption of e-book devices

Electronic books (e-books) are rapidly gaining popularity as a technological innovation that will change the way people read books. A social cognitive perspective to understand how a person adopts an e-book device is utilised in this paper to empirically test the results of a survey. A portion of the conceptual model is supported by the results of the survey that demonstrates the importance of an individual's ethics and entrepreneurial orientation to the adoption behaviour they have about e-book devices. This paper highlights for practitioners the importance of focusing on marketing the ethical and innovativeness of e-book devices.