26 resultados para Transport System Fuctionality

em Deakin Research Online - Australia


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The rapid deployment of intelligent transport systems in practice requires serious evaluation of new construction projects. Traditional transportation evaluation methods are insufficient to capture the new features of intelligent transport systems, particularly the applications of recently developed information technologies. This research aims to develop a new conceptual framework to evaluate the social, economic and environmental impacts of intelligent transport systems deployment, with explicit consideration of impacts of information technologies on variant travel behaviours. The research would provide a systematic evaluation methodology to enable decision makers and publics better evaluating and understanding the social, economic and environmental benefits of implementation of intelligent transport systems.

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In bacteria, limited phosphate availability promotes the synthesis of active uptake systems, such as the Pst phosphate transport system. To understand the mechanisms that facilitate phosphate accumulation in the cyanobacterium Nostoc punctiforme, phosphate transport systems were identified, revealing a redundancy of Pst phosphate uptake systems that exists across three distinct operons. Four separate PstB system components were identified. pstB1 was determined to be a suitable target for creating phenotypic mutations that could result in the accumulation of excessive levels of phosphate through its overexpression or in a reduction of the capacity to accumulate phosphate through its deletion. Using quantitative real-time PCR (qPCR), it was determined that pstB1 mRNA levels increased significantly over 64 h in cells cultured in 0 mM added phosphate and decreased significantly in cells exposed to high (12.8 mM) phosphate concentrations compared to the level in cells cultured under normal (0.8 mM) conditions. Possible compensation for the loss of PstB1 was observed when pstB2, pstB3, and pstB4 mRNA levels increased, particularly in cells starved of phosphate. The overexpression of pstB1 increased phosphate uptake by N. punctiforme and was shown to functionally complement the loss of PstB in E. coli PstB knockout (PstB(-)) mutants. The knockout of pstB1 in N. punctiforme did not have a significant effect on cellular phosphate accumulation or growth for the most part, which is attributed to the compensation for the loss of PstB1 by alterations in the pstB2, pstB3, and pstB4 mRNA levels. This study provides novel in vivo evidence that PstB1 plays a functional role in phosphate uptake in N. punctiforme IMPORTANCE: Cyanobacteria have been evolving over 3.5 billion years and have become highly adept at growing under limiting nutrient levels. Phosphate is crucial for the survival and prosperity of all organisms. In bacteria, limited phosphate availability promotes the synthesis of active uptake systems. The Pst phosphate transport system is one such system, responsible for the internalization of phosphate when cells are in phosphate-limited environments. Our investigations reveal the presence of multiple Pst phosphate uptake systems that exist across three distinct operons in Nostoc punctiforme and functionally characterize the role of the gene product PstB1 as being crucial for the maintenance of phosphate accumulation. We demonstrate that the genes pstB2, pstB3, and pstB4 show alterations in expression to compensate for the deletion of pstB1 The overall outcomes of this work provide insights as to the complex transport mechanisms that exist in cyanobacteria like N. punctiforme, allowing them to thrive in low-phosphate environments.

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Objective: To examine associations of public transport system accessibility with walking, obesity, metabolic syndrome and diabetes/impaired glucose regulation. Methods: Associations of public transport accessibility with self-reported walking for transport or recreation and measured biomarkers of chronic disease risk were estimated in 5241 adult residents of 42 randomly selected areas in Australia in 2004/05, drawn from the second wave of a population-based cohort study (AusDiab). Public transport accessibility was objectively measured using an adaptation of the Public Transport Accessibility Levels (PTAL) methodology, comprising both GIS derived spatial and temporal accessibility measures. Logistic regression models were adjusted for individual and environmental level covariates and clustering within areas. Results: Above median public transport accessibility was positively associated with a walking time of more than the median 90 min per week (OR=1.28, 95%CI 1.03, 1.60) and walking above the recommended 150 min per week (OR=1.35, 95%CI 1.11, 1.63). There were no associations of public transport accessibility with obesity (OR=1.05, 95%CI 0.85, 1.30), the metabolic syndrome (OR=1.09, 95%CI 0.91, 1.31) nor diabetes/impaired glucose regulation (OR=1.11, 95%CI 0.94, 1.30). Findings were similar for a subgroup reporting no vigorous recreational physical activity. Conclusions: In this Australian sample, public transport accessibility was positively associated with walking at recommended levels, including for people who are not otherwise vigorously active. Significance: Walking is crucial for increasing physical activity levels and population health, as well as maximising public transport system efficiency. Building evidence on public transport accessibility and walking will enable governments to exploit this important synergy.

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Zinc homeostasis was investigated in Nostoc punctiforme. Cell tolerance to Zn2+ over 14 days showed that ZnCl2 levels above 22 µM significantly reduced cell viability. After 3 days in 22 µM ZnCl2, ca. 12% of the Zn2+ was in an EDTA-resistant component, suggesting an intracellular localization. Zinquin fluorescence was detected within cells exposed to concentrations up to 37 µM relative to 0 µM treatment. Radiolabeled 65Zn showed Zn2+ uptake increased over a 3-day period, while efflux occurred more rapidly within a 3-h time period. Four putative genes involved in Zn2+ uptake and efflux in N. punctiforme were identified: (i) the predicted Co/Zn/Cd cation transporter, putative CDF; (ii) the predicted divalent heavy-metal cation transporter, putative Zip; (iii) the ATPase component and Fe/Zn uptake regulation protein, putative Fur; and (iv) an ABC-type Mn/Zn transport system, putative zinc ZnuC, ZnuABC system component. Quantitative real-time PCR indicated the responsiveness of all four genes to 22 µM ZnCl2 within 3 h, followed by a reduction to below basal levels after 24 h by putative ZIP, ZnuC, and Fur and a reduction to below basal level after 72 h by putative CDF efflux gene. These results demonstrate differential regulation of zinc transporters over time, indicating a role for them in zinc homeostasis in N. punctiforme.

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Background : Creatine synthesis takes place predominately in the kidney and liver via a two-step process involving AGAT (L-arginine:glycine amidinotransferase) and GAMT (guanidinoacetate methyltransferase). Creatine is taken into cells via the creatine transporter (CrT), where it plays an essential role in energy homeostasis, particularly for tissues with high and fluctuating energy demands. Very little is known of the fetal requirement for creatine and how this may change with advancing pregnancy and into the early neonatal period. Using the spiny mouse as a model of human perinatal development, the purpose of the present study was to comprehensively examine the development of the creatine synthesis and transport systems.

Results : The estimated amount of total creatine in the placenta and brain significantly increased in the second half of pregnancy, coinciding with a significant increase in expression of CrT mRNA. In the fetal brain, mRNA expression of AGAT increased steadily across the second half of pregnancy, although GAMT mRNA expression was relatively low until 34 days gestation (term is 38–39 days). In the fetal kidney and liver, AGAT and GAMT mRNA and protein expression were also relatively low until 34–37 days gestation. Between mid-gestation and term, neither AGAT or GAMT mRNA or protein could be detected in the placenta.

Conclusion : Our results suggest that in the spiny mouse, a species where, like the human, considerable organogenesis occurs before birth, there appears to be a limited capacity for endogenous creatine synthesis until approximately 0.9 of pregnancy. This implies that a maternal source of creatine, transferred across the placenta, may be essential until the creatine synthesis and transport system matures in preparation for birth. If these results also apply to the human, premature birth may increase the risk of creatine deficiency.

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The Fiji Government's inability to resolve the differences over land leases is widely seen as a major contributor to the difficulties experienced by the sugar industry. In this paper, however, a different perspective is provided on the industry's problems. In examining the relationship between the profitability of the Fiji Sugar Corporation and sugarcane production, it is found that profitability has had a statistically significant negative effect on sugarcane production, leading to the conclusion that the Fiji Sugar Corporation has been inefficient in the management of the mills, the rail transport system, and sugarcane research.

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PURPOSE: High-intensity short-duration interval training (HIT) stimulates functional and metabolic adaptation in skeletal muscle, but the influence of HIT on mitochondrial function remains poorly studied in humans. Mitochondrial metabolism as well as mitochondrial-associated protein expression were tested in untrained participants performing HIT over a 2-week period. METHODS: Eight males performed a single-leg cycling protocol (12 × 1 min intervals at 120% peak power output, 90 s recovery, 4 days/week). Muscle biopsies (vastus lateralis) were taken pre- and post-HIT. Mitochondrial respiration in permeabilized fibers, citrate synthase (CS) activity and protein expression of peroxisome proliferator-activated receptor gamma coactivator (PGC-1α) and respiratory complex components were measured. RESULTS: HIT training improved peak power and time to fatigue. Increases in absolute oxidative phosphorylation (OXPHOS) capacities and CS activity were observed, but not in the ratio of CCO to the electron transport system (CCO/ETS), the respiratory control ratios (RCR-1 and RCR-2) or mitochondrial-associated protein expression. Specific increases in OXPHOS flux were not apparent after normalization to CS, indicating that gross changes mainly resulted from increased mitochondrial mass. CONCLUSION: Over only 2 weeks HIT significantly increased mitochondrial function in skeletal muscle independently of detectable changes in mitochondrial-associated and mitogenic protein expression.

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High speed rail (also commonly known as HSR) is highly regarded as one of the most significant innovation for mass passenger transportation to travellers willing to pay for reduced travel impediments (shorter travel time, convenience, safety, security, comfort, reliability, flexibility, uniqueness and attractiveness). The transport policy in Australia has until now focused primarily on private passenger car transport and air transportation to the degree that State and Federal Governments’ commitments and actions of rail-oriented mass transportation system still remains sketchy in spite of occasional political and public attentions into it. This has resulted in a limited use of passenger rail as a regional transport system. Using one of the several alternative HSR alignments proposed for the South-Eastern Coast of Australia connecting Melbourne, Canberra, Sydney and Brisbane, this study assesses the regional accessibility impacts of Australian HSR system by means of four indicators: location accessibility, economic potential accessibility, daily accessibility and commuting accessibility. These indicators are commonly used in transport geography literature and they offer different concepts of changes in regional accessibility conditions due to a long distance transport system. The results provide an understanding of differential effects on regional accessibility based on the geographical location and size of urban areas along HSR corridor.

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The structure and transport of N-propyl-N-methylpyrrolidinium tetrafluoroborate (P13BF4) has been investigated over a wide temperature range in consequence to exhibiting properties suitable for potential solid-state superionic electrolyte applications. Prior to melting, the organic salt, P13BF4, transforms into a plastic crystal phase. Intrinsic conductivity in this solid, phase I (45–65 °C), is comparable to that in the melt (~10−3 S cm−1). Ionic motion and transport properties were investigated by 1H and 11B nuclear magnetic resonance (NMR) spectroscopy. Pressure-induced plastic flow in this system may accommodate volume changes in device application and to this extent, X-ray diffraction (XRD) has been used. Scanning electron microscopy (SEM) revealed complex surface morphology and lattice imperfections associated with the strong orientational disorder of the plastic state.

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The movement of chemicals through the soil to the groundwater or discharged to surface waters represents a degradation of these resources. In many cases, serious human and stock health implications are associated with this form of pollution. The chemicals of interest include nutrients, pesticides, salts, and industrial wastes. Recent studies have shown that current models and methods do not adequately describe the leaching of nutrients through soil, often underestimating the risk of groundwater contamination by surface-applied chemicals and overestimating the concentration of resident solutes. This inaccuracy results primarily from ignoring soil structure and nonequilibrium between soil constituents, water, and solutes. A multiple sample percolation system (MSPS), consisting of 25 individual collection wells, was constructed to study the effects of localized soil heterogeneities on the transport of nutrients (NO−3, Cl−, PO3−4) in the vadose zone of an agricultural soil predominantly dominated by clay. Very significant variations in drainage patterns across a small spatial scale were observed (one-way ANOVA, p < 0.001 indicating considerable heterogeneity in water flow patterns and nutrient leaching. Using data collected from the multiple sample percolation experiments, this paper compares the performance of two mathematical models for predicting solute transport, the advective-dispersion model with a reaction term (ADR), and a two-region preferential flow model (TRM) suitable for modelling nonequilibrium transport. These results have implications for modelling solute transport and predicting nutrient loading on a larger scale.

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Little attention has been paid to the possibility that soil water repellency could enhance non-equilibrium water flow and solute transport through macropores present in structured clay soils. In this study, we measured infiltration and solute transport in a clay soil under near-saturated conditions in both the field using tension infiltrometers and in the laboratory on undisturbed soil columns. Measurements were made on adjacent plots under grass and continuous arable cultivation. Steady-state field infiltration rates measured using water and ethanol as the infiltrating fluids demonstrated that the soil macroporosity under grass was better developed, but that much of the structural pore system was inactive due to water repellency. No water repellency was detected on the arable plot disturbed by tillage. Dye tracing showed that the conducting macroporosity was largely comprised of earthworm channels in the grassed plot and inter-aggregate voids resulting from ploughing in the arable plot. Tracer breakthrough curves measured on field-dry soil indicated rapid macropore transport in columns taken from both plots, although the degree of non-equilibrium transport appeared somewhat stronger under grass. This result, which was attributed to water repellency, was also consistent with the larger flow-weighted mean pore size found in the field infiltration experiments. It is concluded that water repellency in undisturbed structured clay soils can have significant effects on the occurrence of non-equilibrium water and solute transport in macropores.

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As obesity prevention becomes an increasing health priority in many countries, including Australia
and New Zealand, the challenge that governments are now facing is how to adopt a systematic
policy approach to increase healthy eating and regular physical activity. This article sets out a
structure for systematically identifying areas for obesity prevention policy action across the food
system and full range of physical activity environments. Areas amenable to policy intervention can
be systematically identified by considering policy opportunities for each level of governance (local,
state, national, international and organisational) in each sector of the food system (primary
production, food processing, distribution, marketing, retail, catering and food service) and each
sector that influences physical activity environments (infrastructure and planning, education,
employment, transport, sport and recreation). Analysis grids are used to illustrate, in a structured
fashion, the broad array of areas amenable to legal and regulatory intervention across all levels of
governance and all relevant sectors. In the Australian context, potential regulatory policy
intervention areas are widespread throughout the food system, e.g., land-use zoning (primary
production within local government), food safety (food processing within state government), food
labelling (retail within national government). Policy areas for influencing physical activity are
predominantly local and state government responsibilities including, for example, walking and
cycling environments (infrastructure and planning sector) and physical activity education in schools
(education sector). The analysis structure presented in this article provides a tool to systematically
identify policy gaps, barriers and opportunities for obesity prevention, as part of the process of
developing and implementing a comprehensive obesity prevention strategy. It also serves to
highlight the need for a coordinated approach to policy development and implementation across
all levels of government in order to ensure complementary policy action.

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Recent studies have shown that composite polymer electrolytes, formed by dispersing nanosized ceramic particles in polyether-based electrolytes, have improved ion transport properties as compared to their unfilled analogues. In the present study polymer electrolytes with different loadings of nano-sized ceramic particles (TiO2) and different polymer chemistry and morphology have been investigated. Of special interest are filler induced effects on polymer, solvent and cationic mobility. Partly crystalline polymer electrolytes based on poly(ethylene oxide) have been compared to fully amorphous polymer electrolytes based on a polyether urethane, as well as gel electrolytes based on PMMA. 7Li pfg-NMR, linewidth and spin–spin relaxation times as well as 1H pfg-NMR and spin–spin relaxation times, were measured as a function of temperature and composition. The 1H spin–spin relaxation measurements reveal increased average polymer mobility with the addition of filler up to a maximum at 4 and 8 wt.% TiO2 for the fully amorphous and the partly crystalline electrolytes, respectively. The 7Li linewidth measurements for the fully amorphous system show a broadening of the linewidth with addition of filler. Based on variable temperature measurements this broadening is interpreted as a result of the inhomogeneity introduced by the filler particles. Pulsed field gradient (pfg) diffusion measurements were employed to determine ion and solvent self-diffusion coefficients. In the case of the PMMA-based gel electrolyte and the fully amorphous electrolytes enhanced cation self-diffusion was observed upon addition of TiO2.