Convergent evolution in locomotory patterns of flying and swimming animals

Locomotion is one of the major energetic costs faced by animals and various strategies have evolved to reduce its cost. Birds use interspersed periods of flapping and gliding to reduce the mechanical requirements of level flight while undergoing cyclical changes in flight altitude, known as undulating flight. Here we equipped free-ranging marine vertebrates with accelerometers and demonstrate that gait patterns resembling undulating flight occur in four marine vertebrate species comprising sharks and pinnipeds. Both sharks and pinnipeds display intermittent gliding interspersed with powered locomotion. We suggest, that the convergent use of similar gait patterns by distinct groups of animals points to universal physical and physiological principles that operate beyond taxonomic limits and shape common solutions to increase energetic efficiency. Energetically expensive large-scale migrations performed by many vertebrates provide common selection pressure for efficient locomotion, with potential for the convergence of locomotory strategies by a wide variety of species.

Research priorities for child and adolescent physical activity and sedentary behaviours: an international perspective using a twin-panel Delphi procedure

Background
The quantity and quality of studies in child and adolescent physical activity and sedentary behaviour have rapidly increased, but research directions are often pursued in a reactive and uncoordinated manner.

Aim
To arrive at an international consensus on research priorities in the area of child and adolescent physical activity and sedentary behaviour.

Methods
Two independent panels, each consisting of 12 experts, undertook three rounds of a Delphi methodology. The Delphi methodology required experts to anonymously answer questions put forward by the researchers with feedback provided between each round.

Results
The primary outcome of the study was a ranked set of 29 research priorities that aimed to be applicable for the next 10 years. The top three ranked priorities were: developing effective and sustainable interventions to increase children’s physical activity long-term; policy and/or environmental change and their influence on children’s physical activity and sedentary behaviour; and prospective, longitudinal studies of the independent effects of physical activity and sedentary behaviour on health.

Conclusions
These research priorities can help to guide decisions on future research directions.

Contract law : text and cases

A blend of academic commentary supported by key cases providing fundamental knowledge of contract law.

The positive criteria of legal norms: law between facts and norms

Whether an abstract jurisprudence of law can be developed such that law is neutral with respect topositive choices, or whether law is necessarily informed by social facts, values and assumptions, with reference to the work of Jurgden Habermas, countering that author's claim of neutrality.

I wish I was 21 now beyond doping in the Australian peloton

An investigation into the reasons for doping among professional athletes (cyclists) and attitudes towards and assessments of current attempts and form of legislation and regulation of doping, inlcuding prospects for reform, and types of reform required.

Demographic status of Komodo dragons populations in Komodo National Park

The Komodo dragon (Varanus komodoensis) is the world's largest lizard and endemic to five islands in Eastern Indonesia. The current management of this species is limited by a paucity of demographic information needed to determine key threats to population persistence. Here we conducted a large scale trapping study to estimate demographic parameters including population growth rates, survival and abundance for four Komodo dragon island populations in Komodo National Park. A combined capture mark recapture framework was used to estimate demographic parameters from 925 marked individuals monitored between 2003 and 2012. Island specific estimates of population growth, survival and abundance, were estimated using open population capture-recapture analyses. Large island populations are characterised by near or stable population growth (i.e. λ~. 1), whilst one small island population (Gili Motang) appeared to be in decline (λ= 0.68 ± 0.09). Population differences were evident in apparent survival, with estimates being higher for populations on the two large islands compared to the two small islands. We extrapolated island specific population abundance estimates (considerate of species habitat use) to produce a total population abundance estimate of 2448 (95% CI: 2067-2922) Komodo dragons in Komodo National Park. Our results suggest that park managers must consider island specific population dynamics for managing and recovering current populations. Moreover understanding what demographic, environmental or genetic processes act independently, or in combination, to cause variation in current population dynamics is the next key step necessary to better conserve this iconic species.

Life-history and spatial determinants of somatic growth dynamics in Komodo dragon populations

Somatic growth patterns represent a major component of organismal fitness and may vary among sexes and populations due to genetic and environmental processes leading to profound differences in life-history and demography. This study considered the ontogenic, sex-specific and spatial dynamics of somatic growth patterns in ten populations of the world's largest lizard the Komodo dragon (Varanus komodoensis). The growth of 400 individual Komodo dragons was measured in a capture-mark-recapture study at ten sites on four islands in eastern Indonesia, from 2002 to 2010. Generalized Additive Mixed Models (GAMMs) and information-theoretic methods were used to examine how growth rates varied with size, age and sex, and across and within islands in relation to site-specific prey availability, lizard population density and inbreeding coefficients. Growth trajectories differed significantly with size and between sexes, indicating different energy allocation tactics and overall costs associated with reproduction. This leads to disparities in maximum body sizes and longevity. Spatial variation in growth was strongly supported by a curvilinear density-dependent growth model with highest growth rates occurring at intermediate population densities. Sex-specific trade-offs in growth underpin key differences in Komodo dragon life-history including evidence for high costs of reproduction in females. Further, inverse density-dependent growth may have profound effects on individual and population level processes that influence the demography of this species.