Habitat use throughout migration : linking individual consistency, prior breeding success and future breeding potential

1. Habitat use can influence individual performance in a wide range of animals, either immediately or through carry-over effects in subsequent seasons. Given that many animal species also show consistent individual differences in reproductive success, it seems plausible that individuals may have consistent patterns of habitat use representing individual specializations, with concomitant fitness consequences.

2. Stable-carbon isotope ratios from a range of tissues were used to discern individual consistency in habitat use along a terrestrial–aquatic gradient in a long-distance migrant, the Bewick’s swan (Cygnus columbianus bewickii). These individual specialisations represented <15% of the isotopic breadth of the population for the majority of individuals and were seen to persist throughout autumn migration and overwintering until aquatic habitats were no longer available.

3. Individual foraging specialisations were then used to demonstrate two consecutive carry-over effects associated with macroscale habitat segregation: consequences of breeding season processes for autumn habitat use; and consequences of autumn habitat use for future reproductive success. Adults that were successful breeders in the year of capture used terrestrial habitats significantly more than adults that were not successful, revealing a substantial cost of reproduction and extended parental care. Use of aquatic habitats during autumn was, however, associated with increased body condition prior to spring migration; and increased subsequent breeding success in adults that had been unsuccessful the year before. Yet adults that were successful breeders in the year of capture remained the most likely to be successful the following year, despite their use of terrestrial habitats.

4. Our results uniquely demonstrate not only individual foraging specializations throughout the migration period, but also that processes during breeding and autumn migration, mediated by individual consistency, may play a fundamental role in the population dynamics of long-distance migrants. These findings, therefore, highlight the importance of long-term consistency to our understanding of habitat function, interindividual differences in fitness, population dynamics and the evolution of migratory strategies.

Does the choice of neighbourhood supermarket access measure influence associations with individual-level fruit and vegetable consumption? A case study from Glasgow

Background
Previous studies have provided mixed evidence with regards to associations between food store access and dietary outcomes. This study examines the most commonly applied measures of locational access to assess whether associations between supermarket access and fruit and vegetable consumption are affected by the choice of access measure and scale.

Method
Supermarket location data from Glasgow, UK (n = 119), and fruit and vegetable intake data from the 'Health and Well-Being' Survey (n = 1041) were used to compare various measures of locational access. These exposure variables included proximity estimates (with different points-of-origin used to vary levels of aggregation) and density measures using three approaches (Euclidean and road network buffers and Kernel density estimation) at distances ranging from 0.4 km to 5 km. Further analysis was conducted to assess the impact of using smaller buffer sizes for individuals who did not own a car. Associations between these multiple access measures and fruit and vegetable consumption were estimated using linear regression models.

Results
Levels of spatial aggregation did not impact on the proximity estimates. Counts of supermarkets within Euclidean buffers were associated with fruit and vegetable consumption at 1 km, 2 km and 3 km, and for our road network buffers at 2 km, 3 km, and 4 km. Kernel density estimates provided the strongest associations and were significant at a distance of 2 km, 3 km, 4 km and 5 km. Presence of a supermarket within 0.4 km of road network distance from where people lived was positively associated with fruit consumption amongst those without a car (coef. 0.657; s.e. 0.247; p0.008).

Conclusions
The associations between locational access to supermarkets and individual-level dietary behaviour are sensitive to the method by which the food environment variable is captured. Care needs to be taken to ensure robust and conceptually appropriate measures of access are used and these should be grounded in a clear a priori reasoning.

Personality and the effort-reward imbalance model of stress : individual differences in reward sensitivity

The Effort-Reward Imbalance (ERI) model comprises both situational components (i.e. effort and reward) and a person-specific component (overcommitment). The aims of this study were to investigate the role of theoretically and historically linked personality variables (i.e. overcommitment and Type A personality) within the ERI model and to expand and extend the ERI model by investigating the contribution of individual reward components to both psychological (i.e. psychological distress) and attitudinal (i.e. affective commitment) employee strain indicators. A total of 897 police officers from a large Australian police agency participated in the study. The results provided no evidence of an interaction effect of effort or reward with overcommitment. The Type A variables did, however, make significant contributions and were involved in a number of interactions, suggesting that the person-specific component of the ERI model could be extended with the Type A personality profile. The findings also suggest that the esteem component of reward has the greatest relevance to employee outcomes, although tangible aspects of reward are more likely to act as a buffer of perceived work demand.

Neighborhood disadvantage, individual-level socioeconomic position, and self-reported chronic arthritis : a cross-sectional multilevel study

Objective To examine the association between individual- and neighborhood-level disadvantage and self-reported arthritis.

Methods We used data from a population-based cross-sectional study conducted in 2007 among 10,757 men and women ages 40–65 years, selected from 200 neighborhoods in Brisbane, Queensland, Australia using a stratified 2-stage cluster design. Data were collected using a mail survey (68.5% response). Neighborhood disadvantage was measured using a census-based composite index, and individual disadvantage was measured using self-reported education, household income, and occupation. Arthritis was indicated by self-report. Data were analyzed using multilevel modeling.

Results The overall rate of self-reported arthritis was 23% (95% confidence interval [95% CI] 22–24). After adjustment for sociodemographic factors, arthritis prevalence was greatest for women (odds ratio [OR] 1.5, 95% CI 1.4–1.7) and in those ages 60–65 years (OR 4.4, 95% CI 3.7–5.2), those with a diploma/associate diploma (OR 1.3, 95% CI 1.1–1.6), those who were permanently unable to work (OR 4.0, 95% CI 3.1–5.3), and those with a household income <$25,999 (OR 2.1, 95% CI 1.7–2.6). Independent of individual-level factors, residents of the most disadvantaged neighborhoods were 42% (OR 1.4, 95% CI 1.2–1.7) more likely than those in the least disadvantaged neighborhoods to self-report arthritis. Cross-level interactions between neighborhood disadvantage and education, occupation, and household income were not significant.

Conclusion Arthritis prevalence is greater in more socially disadvantaged neighborhoods. These are the first multilevel data to examine the relationship between individual- and neighborhood-level disadvantage upon arthritis and have important implications for policy, health promotion, and other intervention strategies designed to reduce the rates of arthritis, indicating that intervention efforts may need to focus on both people and places.

An approach to assign individual marks from a team mark : the case of Australian grading system at universities

This study uses a new approach to assign individual marks from a team mark using individual contributions to a teamwork product. A team member’s contribution to a teamwork product, in the form of an individual weighting factor, is calculated using team members’ co‐assessment. A comparison of the proposed approach with existing methods has been discussed with the help of a typical teamwork example. The approach has been refined to make it applicable for the Australian grading system at universities. It has been implemented in a large undergraduate engineering course to observe its effectiveness in practice. The results show that the method encourages teamwork, penalises below‐average contributions and rewards above‐average contributions. An analysis of a students’ perception survey shows that students prefer the approach over alternative approaches.

Are most samples of animals systematically biased? Consistent individual trait differences bias samples despite random sampling

Sampling animals from the wild for study is something nearly every biologist has done, but despite our best efforts to obtain random samples of animals, ‘hidden’ trait biases may still exist. For example, consistent behavioral traits can affect trappability/catchability, independent of obvious factors such as size and gender, and these traits are often correlated with other repeatable physiological and/or life history traits. If so, systematic sampling bias may exist for any of these traits. The extent to which this is a problem, of course, depends on the magnitude of bias, which is presently unknown because the underlying trait distributions in populations are usually unknown, or unknowable. Indeed, our present knowledge about sampling bias comes from samples (not complete population censuses), which can possess bias to begin with. I had the unique opportunity to create naturalized populations of fish by seeding each of four small fishless lakes with equal densities of slow-, intermediate-, and fast-growing fish. Using sampling methods that are not size-selective, I observed that fast-growing fish were up to two-times more likely to be sampled than slower-growing fish. This indicates substantial and systematic bias with respect to an important life history trait (growth rate). If correlations between behavioral, physiological and life-history traits are as widespread as the literature suggests, then many animal samples may be systematically biased with respect to these traits (e.g., when collecting animals for laboratory use), and affect our inferences about population structure and abundance. I conclude with a discussion on ways to minimize sampling bias for particular physiological/behavioral/life-history types within animal populations.

Actuating individual electrospun hydrogel nanofibres

The actuation of a single hydrogel nanofibre is measured for the first time by AFM. The actuation stress generated was comparable to that produced by skeletal muscle and the actuation rate was significantly increased by the nanoscale dimensions of the fibre.

Do consistent individual differences in metabolic rate promote consistent individual differences in behavior?

Consistent individual differences (CIDs) in behavior are a widespread phenomenon in animals, but the proximate reasons for them are unresolved. We discuss evidence for the hypothesis that CIDs in energy metabolism, as reflected by resting metabolic rate (RMR), promote CIDs in behavior patterns that either provide net energy (e.g. foraging activity), and/or consume energy (e.g. courtship activity). In doing so, we provide a framework for linking together RMR, behavior, and life-history productivity. Empirical studies suggest that RMR is (a) related to the capacity to generate energy, (b) repeatable, and (c) correlated with behavioral output (e.g. aggressiveness) and productivity (e.g. growth). We conclude by discussing future research directions to clarify linkages between behavior and energy metabolism in this emerging research area.

Individual variation in foraging movements in a lake population of young-of-the-year brook charr (Salvelinus fontinalis)

We examined the variation in foraging movements in a population of young-of-the-year (YOY) brook charr living in the near-shore littoral zone of a lake. By repeating the methodology of an earlier stream study, we made direct comparisons between data from lake and stream populations. In general, the pattern of variation in foraging movements was similar between the two sites with greater variability and activity observed in the lake population. The dichotomous nature of the proportion of time spent moving in the stream was also observed in the lake population but in a reversal of the stream pattern. Charr that moved constantly while foraging represented the largest movement category in the lake. In general, variation in foraging movements were more strongly related to the rate of prey rejection, whereas environmental factors, such as distance from shore, submerged objects, and the amount of overhead riparian cover, were more strongly related to prey ingestion. This last finding directly contrasts with that found in the stream literature for YOY charr in still water where ingestion rate, as estimated using feeding attempt rate, increases with the mobility of YOY charr.

A bayesian nonparametric joint factor model for learning shared and individual subspaces from multiple data sources

Joint analysis of multiple data sources is becoming increasingly popular in transfer learning, multi-task learning and cross-domain data mining. One promising approach to model the data jointly is through learning the shared and individual factor subspaces. However, performance of this approach depends on the subspace dimensionalities and the level of sharing needs to be specified a priori. To this end, we propose a nonparametric joint factor analysis framework for modeling multiple related data sources. Our model utilizes the hierarchical beta process as a nonparametric prior to automatically infer the number of shared and individual factors. For posterior inference, we provide a Gibbs sampling scheme using auxiliary variables. The effectiveness of the proposed framework is validated through its application on two real world problems - transfer learning in text and image retrieval.

School and individual-level characteristics are associated with children's moderate to vigorous intensity physical activity during school recess

Objective: The objective of this study was to identify school environmental characteristics associated with moderate to vigorous physical activity during school recess, including morning and lunch breaks.

Methods: Accelerometry data, child-level characteristics and school physical activity, policy and socio-cultural data were collected from 408 sixth grade children (mean age 11 years) attending 27 metropolitan primary schools in Perth, Western Australia. Hierarchical modelling identified key characteristics associated with children's recess moderate to vigorous physical activity (RMVPA).

Results: Nearly 40% of variability in children's RMVPA was explained by school environment and individual characteristics identified in this study. Children's higher daily RMVPA was associated with newer schools, schools with a higher number of grassed surfaces per child and fewer shaded grassed surfaces, and the physical education coordinator meeting Australian physical activity guidelines.

Conclusions: Characteristics of the school physical and social environments are strongly correlated with children's MPVA during recess.

A re-examination of the benefits of exercise for state body satisfaction: Considerationof individual difference factors

Although the link between exercise and body image is well documented, the considerable inter-individual variability in this relationship has been largely ignored. Therefore, the aim of the present study was to test the contributions of key body image and exercise-related moderators (age, body mass index (BMI), exercise frequency, trait body dissatisfaction, internalisation of appearance standards, and body surveillance tendencies) in predicting variability in the exercise-body satisfaction relationship. Thirty-seven undergraduate women completed a questionnaire containing the above trait-based measures and then carried a Personal Digital Assistant (PDA) for a 7-day period. Participants were instructed to use the PDA to self-report their state body satisfaction immediately following an exercise session and also when the PDA signalled at each of six random intervals throughout the day. Multilevel modelling revealed a bi-directional relationship between exercise and state body satisfaction. Moreover, post-exercise increases in state body satisfaction were strongest for individuals who were younger and engaged in regular exercise, and weakest for individuals with high BMI and/or the tendency to compare their appearance with others. These findings highlight potential limits on the efficacy of exercise-based therapy for body image disturbances.

Wikis as individual student learning tools : the limitations of technology

This paper presents research into the attitudes and behaviours of students using wikis for individual writing tasks. The wiki-based assignment differs from the use of wikis normally researched because it was an individual task, not involving collaborative writing. This activity provides an excellent opportunity to learn more about how wikis are actually used by students in higher education. The research finds there is no compelling evidence that the wiki on its own improves performance over and above the general aptitude of students. It also finds that students generally did not utilise the wikis for high-intensity editing and revision. However, students did report that the wiki was valuable as a way of aiding them to review and develop their ideas. We conclude that using wikis for individual writing tasks can, where appropriate active instructions are given to support development of cognitive abilities, lead to improved outcomes for students.