Pre-exercise nutritional strategies: effects on metabolism and performance

The goals of pre-exercise nutritional strategies are to optimise the availability of carbohydrate (CHO) and fluid. Ingestion of CHO 3-4 hr prior to exercise can increase liver and muscle glycogen stores and has been associated with enhanced endurance exercise performance. The metabolic effects of CHO ingestion persist for at least 6 hr. Although an increase in plasma insulin following CHO ingestion in the hour prior to exercise inhibits lipolysis and liver glucose output, and can lead to transient hypoglycemia during subsequent exercise, there is no convincing evidence that this is always associated with impaired exercise performance. Having said that, individual experience should inform individual practice. Interventions to increase plasma FFA availability prior to exercise have been shown to reduce CHO utilisation during exercise, but do not appear to have major ergogenic benefits. It is more difficult to hyperhydrate prior to exercise and although there has been interest in glycerol ingestion, to date research results have been equivocal. At the very least, athletes should ensure euhydration prior to exercise.

Pre-exercise carbohydrate and fat ingestion : effects on metabolism and performance

A key goal of pre-exercise nutritional strategies is to maximize carbohydrate stores, thereby minimizing the ergolytic effects of carbohydrate depletion. Increased dietary carbohydrate intake in the days before competition increases muscle glycogen levels and enhances exercise performance in endurance events lasting 90 min or more. Ingestion of carbohydrate 3-4 h before exercise increases liver and muscle glycogen and enhances subsequent endurance exercise performance. The effects of carbohydrate ingestion on blood glucose and free fatty acid concentrations and carbohydrate oxidation during exercise persist for at least 6 h. Although an increase in plasma insulin following carbohydrate ingestion in the hour before exercise inhibits lipolysis and liver glucose output, and can lead to transient hypoglycaemia during subsequent exercise in susceptible individuals, there is no convincing evidence that this is always associated with impaired exercise performance. However, individual experience should inform individual practice. Interventions to increase fat availability before exercise have been shown to reduce carbohydrate utilization during exercise, but do not appear to have ergogenic benefits.

Plant natriuretic peptide active site determination and effects on cGMP and cell volume regulation

Natriuretic peptides (NP) were first identified in animals where they play a role in the regulation of salt and water balance. This regulation is partly mediated by intracellular changes in cyclic GMP (cGMP). NP immunoanalogues occur in many plants and have been isolated, with two NP encoding genes characterised in Arabidopsis thaliana L. (AtPNP-A and AtPNP-B). Part of AtPNP-A contains the region with homology to human atrial (A)NP. We report here on the effects of recombinant AtPNP-A and smaller synthetic peptides within the ANP-homologous region with a view to identifying the biologically active domain of the molecule. Furthermore, we investigated interactions between AtPNP-A and the hormone, abscisic acid (ABA). ABA does not significantly affect Arabidopsis mesophyll protoplast volume regulation, whereas AtPNP-A and synthetic peptides promote water uptake into the protoplasts causing swelling. This effect is promoted by the membrane permeable cGMP analogue, 8-Br-cGMP, and inhibited by guanylate cyclase inhibitors indicating that increases in cGMP are an essential component of the plant natriuretic peptides (PNP) signalling cascade. ABA does not induce cGMP transients and does not affect AtPNP-A dependent cGMP increases, hence the two regulators differ in their second messenger signatures. Interestingly, AtPNP-A significantly delays and reduces the extent of ABA stimulated stomatal closure that is also based on cell volume regulation. We conclude that a complex interplay between observed PNP effects (stomatal opening and protoplast swelling) and ABA is likely to be cell type specific.

Ageing effects on knee and ankle joint angles at key events and phases of the gait cycle.

The objective of this research was to determine whether joint angles at critical gait events and during major energy generation/absorption phases of the gait cycle would reliably discriminate age-related degeneration during unobstructed walking. The gaits of 24 healthy adults (12 young and 12 elderly) were analysed using the PEAK Motus motion analysis system. The elderly participants showed significantly greater single (60.3% versus 62.3%, p < 0.01) and double ( p < 0.05) support times, reduced knee flexion (47.7° versus 43.0°, p < 0.05) and ankle plantarflexion (16.8° compared to 3.3°, p = 0.053) at toe off, reduced knee flexion during push-off and reduced ankle dorsiflexion (16.8° compared to 22.0°, p < 0.05) during the swing phase. The plantarflexing ankle joint motion during the stance to swing phase transition (A₂) for the young group (31.3°) was about twice ( p < 0.05) that of the elderly (16.9°). Reduced knee extension range of motion suggests that the elderly favoured a flexed-knee gait to assist in weight acceptance. Reduced dorsiflexion by the elderly in the swing phase implies greater risk of toe contact with obstacles. Overall, the results suggest that joint angle measures at critical events/phases in the gait cycle provide a useful indication of age-related degeneration in the control of lower limb trajectories during unobstructed walking.

Compositional effects on structure and transport properties in a polyelectrolyte gel

The copolymerization of lithium 2-acrylamido-2-methyl-1-propane sulfonate (LiAMPS) with N,N ′-dimethylacrylamide has yielded polyelectrolyte systems which can be gelled with an ethylene carbonate/N ′,N ′-dimethylacetamide solvent mixture and show high ionic conductivities. 7Li linewidth and relaxation times as well as 1H NMR diffusion coefficients have been used to investigate the effect of copolymer composition as well as copolymer concentration in the gel electrolyte with respect to ionic transport and polyelectrolyte structure. It appears that ion association is likely even in the case of low lithium salt concentration; however a rapid exchange exists between the associated and non-associated lithium species. Beyond 0.2 M of LiAMPS, both the conductivity and solvent diffusion reach a plateau, whilst lithium ion linewidth and spin-spin relaxation are suggestive, on average, of a less mobile species. The thermal analysis data is also supportive of this association effectively leading to a form of phase separation on the nanoscale, which gives a lower overall activity of lithium ions in the solvent rich regions beyond about 0.2 M of LiAMPS, thereby leading to an increase in the final liquidus temperature of the binary liquid solvent from –9 to +5°C.

Increasing Iron and Zinc in Pre-Menopausal Women and Its Effects on Mood and Cognition: A Systematic Review.

Iron and zinc are essential minerals often present in similar food sources. In addition to the adverse effects of frank iron and zinc-deficient states, iron insufficiency has been associated with impairments in mood and cognition. This paper reviews current literature on iron or zinc supplementation and its impact on mood or cognition in pre-menopausal women. Searches included MEDLINE complete, Excerpta Medica Database (EMBASE), psychINFO, psychARTICLES, pubMED, ProQuest Health and Medical Complete Academic Search complete, Scopus and ScienceDirect. Ten randomized controlled trials and one non-randomized controlled trial were found to meet the inclusion criteria. Seven studies found improvements in aspects of mood and cognition after iron supplementation. Iron supplementation appeared to improve memory and intellectual ability in participants aged between 12 and 55 years in seven studies, regardless of whether the participant was initially iron insufficient or iron-deficient with anaemia. The review also found three controlled studies providing evidence to suggest a role for zinc supplementation as a treatment for depressive symptoms, as both an adjunct to traditional antidepressant therapy for individuals with a diagnosis of major depressive disorder and as a therapy in its own right in pre-menopausal women with zinc deficiency. Overall, the current literature indicates a positive effect of improving zinc status on enhanced cognitive and emotional functioning. However, further study involving well-designed randomized controlled trials is needed to identify the impact of improving iron and zinc status on mood and cognition.

Computational studies to understand the role of social learning in team familiarity and its effects on team performance

This paper concerns social learning modes and their effects on team performance. Social learning, such as by observing others' actions and their outcomes, allows members of a team to learn what other members know. Knowing what other members know can reduce task communication and co-ordination overhead, which helps the team to perform faster since members can devote their attention to their tasks. This paper describes agent-based simulation studies using a computational model that implements different social learning modes as parameters that can be controlled in the simulations. The results show that social learning from both direct and indirect observations positively contributes to learning about what others know, but the value of social learning is sensitive to prior familiarity such that minimum thresholds of team familiarity are needed to realise the benefits of social learning. This threshold increases with task complexity. These findings clarify the level of influence that sociality has on social learning and sets up a formal framework by which to conduct studies on how social context influences learning and group performance.

The effects of technical and social conditions on workplace trust

This paper investigates the extent to which the technical and social contexts of organizations independently affect levels of workplace trust. We argue that, in an organizational context, trust is not just a relationship between an individual subject (the truster) and an object (the trustee) but is subject to effects from the conditions of the work relationship itself. We describe the organizational context as comprising both a technical system of production (where work gets done through the specification of tasks) and a social system of work (where problems of effort, compliance, conformity and motivation are managed). We analyse the relationship between trust and these two aspects of workplace context (technical and social systems). We also operationalize this in terms of differences between industries,  occupational composition and human resource management practices. The model is tested using data drawn from the 1995 Australian Workplace Industrial Relations Survey. The results confirm that differences in industry, occupational composition and HRM practices all impact on levels of workplace trust. We review these results in terms of their implications for future research into the problem of analysing variation in trust at both the workplace and individual levels.

Wool industry : a decade of turbulence : an examination of some of the factors contributing to the crisis within Australia's wool industry, and the resulting economic, social and demographic effects on a small isolated rural community

A central issue of this thesis has been an examination of the effects that the current wool crisis has had on the Balmoral district, an area almost solely devoted to the production of wool and wool sheep. Examines the methods being utilised to try to alleviate some of these effects.

The differential effects of Autism and Down's Syndrome on sexual behavior.

Although sexuality plays a major role in the socialization of people, few studies have examined the sexual behaviors of individuals with developmental disabilities. Because of this, we decided to investigate sexuality in adolescents with autism spectrum disorder (ASD) and Down's syndrome (Ds) and to compare them with typically developing adolescents, by surveying their parents. Specifically, it was hypothesized that young people with ASD would display lower levels over five domains: social behavior, privacy, sex education, sexual behavior, and parental concerns, than peers with Ds and typically developing young people. In addition, we sought to verify developmental trends in five domains with age for each group. Overall, 269 parents participated; 94 parents of typically developing adolescents, 93 parents of adolescents diagnosed with Ds, and 82 parents of adolescents diagnosed with ASD. Participants were surveyed with a Sexual Behavior Scale developed by Stokes and Kaur [] that assesses parents' reports of their child's: social behavior, privacy awareness, sex education, sexual behavior and parental concerns about the child's behaviors. It was found that three groups were significantly different on all five domains, adolescents with ASD reportedly displaying lower levels than other groups. Moreover, there was a significant improvement in knowledge of privacy and parental concerns with age for adolescents with ASD and a decline in sex education for adolescents with Ds. The results obtained emphasize the need to train adolescents with developmental disability, and especially for adolescents with ASD through sex education programs. Autism Res 2015.