Identification-based Diagnosis of Rainfall ¿Stream Flow Data: the Tinderry Catchment

System identification tools, such as transfer function (TF) model structure identification, recursive estimation, time-varying parameter (TVP) estimation and assessment of data information, are used to evaluate the quality of rainfall-stream flow data from the Tinderry catchment (ACT, Australia) and the timevarying behaviour of the rainfall-stream flow dynamics. For the catchment, given the wide range and the abrupt changes of the single input-single output transfer functions describing different periods or events, we conclude that further investigation of (i) local rainfall effects, (ii) time-varying time delays (travelling time), (iii) time-varying residence times related to the base flow and (iv) occurrence of negative residues is needed. Periods with high and low data information content, for further use in effective parameter estimation procedures, are clearly indicated by the analysis

Efficacy of a four-week uphill sprint training intervention in field hockey players

Current evidence increasingly suggests that very short, supra-maximal bouts of exercise can have significant health and performance benefits. The majority of research conducted in the area however, uses laboratory-based protocols, which can lack ecological validity. The purpose of this study was to examine the effects of a high intensity sprint-training programme on hockey related performance measures. 14 semi-professional hockey players completed either a 4-week high intensity training (HIT) intervention, consisting of a total of six sessions HIT, which progressively increased in volume (n=7), or followed their normal training programme (Con; n=7). Straight-line sprint speed with and without a hockey stick and ball, and slalom sprint speed, with and without a hockey stick and ball were used as performance indicators. Maximal sprint speed over 22.9m was also assessed. Upon completion of the four-week intervention, straight-line sprint speed improved significantly in the HIT group (~3%), with no change in performance for the Con group. Slalom sprint speed, both with and without a hockey ball was not significantly different following the training programme in either group. Maximal sprint speed improved significantly (12.1%) in the HIT group, but there was no significant performance change in the Con group. The findings of this study indicate that a short period of HIT can significantly improve hockey related performance measures, and could be beneficial to athletes and coaches in field settings

The bone-protective effect and mechanism of soluble corn fiber

Postmenopausal women are at greatest risk among healthy individuals of developing osteoporosis and associated fractures. Nondigestible, fermentable dietary carbohydrates have been shown to improve calcium absorption in adolescents and bone-strength parameters in the rat model. Of particular interest is soluble corn fiber (SCF), which improved rat bone strength the most in a survey of novel fibers, and improved calcium absorption by up to 13% in teen girls. Hypotheses about the mechanism behind this effect revolve around the production of short-chain fatty acids (SCFAs) in the large intestine during fermentation. The purpose of this work was to determine if SCF would also benefit postmenopausal women and to assess the effect on calcium absorption of a chronic increase in cecal concentrations of SCFAs in rats.^ To study the effect of SCF, a randomized, double-blind, placebo-controlled crossover design was used to assess the effects of daily consumption of 0, 10, and 20 g SCF on bone calcium retention in postmenopausal women. SCF was provided as PROMITOR® 85 SCF, which provides 85% fiber, and was consumed as a constituent of one muffin and one fruit-flavored drink daily for 50 days. To measure net bone calcium loss, participants\u27 bones were labeled with 41Ca by administration of ≥50 nCi of 41Ca intravenously at least 100 d prior to the start of the study. Every 10 days, 24 h urine was collected, and 41Ca appearance was measured sensitively by Accelerator Mass Spectrometry, while total Ca was measured by ICP-MS. Urinary 41Ca:Ca from nonintervention periods was used to determine an expected rate of bone loss. A decrease in urinary41Ca:Ca from the expected amount during intervention periods reflected increased bone retention. A dose-response effect was demonstrated, with 10 g/d SCF and 20 g/d SCF improving bone calcium retention by 4.8% (P = 0.013) and 7% (0.007) respectively. Bone formation marker bone-specific alkaline phosphatase (BAP), and bone turnover markers osteocalcin (OC) and N-terminal telopeptide (NTx), were measured at the ends of the baseline period and each washout and intervention period. Of the biomarkers measured, the only statistically significant difference detected was measured in BAP, between placebo and 20 g/d SCF (8%, P = 0.035). Daily SCF consumption significantly increased bone retention in postmenopausal women. It is estimated that 20 g/d SCF would improve bone balance by 50 mg/d, or 2.5% total body BMC per year if the effect persists.^ To assess the effectiveness of SCFAs to increase calcium absorption, rats were chronically dosed in a randomized, placebo-controlled trial with SCFAs. Twice daily, the rats received 0, 300, or 600 umol SCFA conjugate base directly to their ceca through a cecal catheter. At the end of 11 days, 45Ca was administered to their ceca, and 45Ca appearance was measured in their plasma. No statistically significant difference was observed between treatments.^ These studies indicate that SCF, in achievable dietary intakes, is effective in supporting bone health in postmenopausal women, but also that increasing SCFA concentration in the large intestine may not be the only mechanism causing this benefit. It is possible that the protocol used to assess the effect of chronic SCFA dosing on calcium absorption is inadequate. New protocols should be considered, and other mechanisms, such as a shift in gut pH or microbial populations, should be assessed for their effects on calcium absorption

IWRAM: An integrated toolbox for considering impacts of development and land use change in Northern Thailand

The IWRAM Decision Support System was developed to consider economic, environmental, and sociocultural trade-offs involved with resource competition and development in the Mae Chaem catchment in Northern Thailand. IWRAM contains two modelling toolboxes utilising a nodal network structure for catchment analysis: a Biophysical Toolbox, for considering the biophysical (erosion, streamflow, crop) implications of 'painted on' land use scenarios; and, an Integrated Modelling Toolbox, which links models of household decision making with the biophysical toolbox to allow for consideration of socioeconomic and environmental trade-offs of many development and policy scenarios. This paper describes the Integrated Modelling Toolbox within the IWRAM system. Links between household decision models, a socioeconomic impacts model and the biophysical toolbox are described and results for a number of forest encroachment scenarios are demonstrated using key indicators of social, economic and environmental performance. The potential for reapplication of the modelling framework to a large number of catchment situations is also discussed. (Résumé d'auteur