675 resultados para net zero energy


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The extracellular glutamate concentration ([glu]o) rises during cerebral ischemia, reaching levels capable of inducing delayed neuronal death. The mechanisms underlying this glutamate accumulation remain controversial. We used N-methyl-d-aspartate receptors on CA3 pyramidal neurons as a real-time, on-site, glutamate sensor to identify the source of glutamate release in an in vitro model of ischemia. Using glutamate and l-trans-pyrrolidine-2,4-dicarboxylic acid (tPDC) as substrates and dl-threo-β-benzyloxyaspartate (TBOA) as an inhibitor of glutamate transporters, we demonstrate that energy deprivation decreases net glutamate uptake within 2–3 min and later promotes reverse glutamate transport. This process accounts for up to 50% of the glutamate accumulation during energy deprivation. Enhanced action potential-independent vesicular release also contributes to the increase in [glu]o, by ≈50%, but only once glutamate uptake is inhibited. These results indicate that a significant rise in [glu]o already occurs during the first minutes of energy deprivation and is the consequence of reduced uptake and increased vesicular and nonvesicular release of glutamate.

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"Contract AT(30-1)-2789."

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It is shown, through numerical simulations, that by using a combination of dispersion management and periodic saturable absorption it is possible to transmit solitonlike pulses with greatly increased energy near to the zero net dispersion wavelength. This system is shown to support the stable propagation of solitons over transoceanic distances for a wide range of input powers.

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The authors study experimentally ~10 ps return-to-zero pulse propagation near the net dispersion zero of an optical fibre transmission line. Stable near-jitter-free propagation was observed over 70 Mm. Pulse stabilisation and ASE suppression were achieved through the saturable aborber mechanism of nonlinear polarisation rotation.

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The authors study experimentally ~10 ps return-to-zero pulse propagation near the net dispersion zero of an optical fibre transmission line. Stable near-jitter-free propagation was observed over 70 Mm. Pulse stabilisation and ASE suppression were achieved through the saturable aborber mechanism of nonlinear polarisation rotation.

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It is shown, through numerical simulations, that by using a combination of dispersion management and periodic saturable absorption it is possible to transmit solitonlike pulses with greatly increased energy near to the zero net dispersion wavelength. This system is shown to support the stable propagation of solitons over transoceanic distances for a wide range of input powers.

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Acknowledgements K. Ashbrook, M. Barrueto, K. Elner, A. Hargreaves, S. Jacobs, G. Lancton, M. LeVaillant, E. Grosbellet, A. Moody, A. Ronston, J. Provencher, P. Smith, K. Woo and P. Woodward helped in the field. J. Nakoolak kept us safe from bears. N. Sapir and two anonymous reviewers provided very useful comments on an earlier version of our manuscript. R. Armstrong at the Nunavut Research Institute, M. Mallory at the Canadian Wildlife Service Northern Research Division and C. Eberl at National Wildlife Research Centre in Ottawa provided logistical support. F. Crenner, N. Chatelain and M. Brucker customized the GPS at the IPHC-CNRS. KHE received financial support through a NSERC Vanier Canada Graduate Scholarship, ACUNS Garfield Weston Northern Studies scholarship and AINA Jennifer Robinson Scholarship and JFH received NSERC Discovery Grant funding. J. Welcker generously loaned some accelerometers. All procedures were approved under the guidelines of the Canadian Council for Animal Care.

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Australia’s current pattern of residential development is resulting in urban sprawl and highlights the necessity for development to be more sustainable to avoid unnecessary demand on natural resources and to prevent environmental degradation and to safeguard the environment for future generations. This report summarises the results from a series of cases studies that examined the link between sub-divisional layout and dwelling energy efficiency, the possibility for a lot-rating tool and the potential for on site electricity generation.

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This paper will summarise the findings from a study that explored the link between dwelling design, or type, and energy efficiencies in sub-tropical climates. An increasing number of government and private sector development companies are initiating projects that aim to deliver enhanced environmental outcomes at both sub-divisional and dwelling levels. The study used AccuRate, a new thermal modelling tool developed by CSIRO that responds to the need to improve ventilation modelling. The study found that dwellings developed in conjunction with the Departments of Housing and Public Works have set the benchmark. It provides a snapshot of the energy efficiency of a range of dwelling types found in recent subdivisions. However, the trend toward increasing urban densities may reduce the likelihood that cooling breezes will be available to cool dwellings. The findings are relevant to regulators, designers and industry in all states interested in reducing the energy used to cool dwellings in summer.

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Worldwide, the current pattern of urban development is unsustainable and metropolitan planning and development strategies deliver poor environmental outcomes in relation to energy production. As a result, an increasing number of governments and private sector development companies are initiating projects that aim to deliver enhanced environmental outcomes rather than a ‘business as usual’ approach. This paper will summarise the findings from a study that explored the link between building orientation and energy efficiencies in sub-tropical and tropical climates. The study used a new thermal modelling software tool developed by CSIRO that responds more accurately to residential heating and cooling energy performance in those climate zones. This software tool responds to industry criticisms regarding cold climate modelling systems that do not make sufficient allowance for natural ventilation. The study examined a range of low, medium and high-density dwelling types and investigated the impact of orientation, insulation, ventilation and shading devices on energy efficiencies. This paper will examine the findings from the medium and high-density case study developments as these are relevant to residential developments in many South East Asian countries, such as Singapore, Hong Kong and Malaysia. Finally, the paper will explore the potential benefits that medium and high-density residential developments have in the development of ‘solar cities’ and ‘solar suburbs’.

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This report summarises the findings from the Sustainable Subdivisions: Energy-Efficient Design project. As new energy-efficiency regulations are developed, there will be a significant demand for information on available assessment tools for rating energy-efficient dwellings, and subdivisional issues such as orientation and solar access will become increasingly important. There will also be increased pressure for products that deliver energy efficiency, such as solar technology, glazing systems, insulation and low-energy building products and materials. The objectives of the Sustainable Subdivisions: Energy-Efficient Design project were to: