6,843 research outputs found

    Minkowski Functionals and Cluster Analysis for CMB Maps

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    We suggest novel statistics for the CMB maps that are sensitive to non-Gaussian features. These statistics are natural generalizations of the geometrical and topological methods that have been already used in cosmology such as the cumulative distribution function and genus. We compute the distribution functions of the Partial Minkowski Functionals for the excursion set above or bellow a constant temperature threshold. Minkowski Functionals are additive and are translationally and rotationally invariant. Thus, they can be used for patchy and/or incomplete coverage. The technique is highly efficient computationally (it requires only O(N) operations, where N is the number of pixels per one threshold level). Further, it allows to split large data sets into smaller subsets. The full advantage of these statistics can be obtained only on very large data sets. We apply it to the 4-year DMR COBE data corrected for the Galaxy contamination as an illustration of the technique.Comment: 28 pages latex using aasms4 and epsfig. 11 postscript figures embedded. Minor Changes, to reflect the published versio

    Preparation of Dicke States in an Ion Chain

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    We have investigated theoretically and experimentally a method for preparing Dicke states in trapped atomic ions. We consider a linear chain of NN ion qubits that is prepared in a particular Fock state of motion, m>|m>. The mm phonons are removed by applying a laser pulse globally to the NN qubits, and converting the motional excitation to mm flipped spins. The global nature of this pulse ensures that the mm flipped spins are shared by all the target ions in a state that is a close approximation to the Dicke state \D{N}{m}. We calculate numerically the fidelity limits of the protocol and find small deviations from the ideal state for m=1m = 1 and m=2m = 2. We have demonstrated the basic features of this protocol by preparing the state \D{2}{1} in two 25^{25}Mg+^+ target ions trapped simultaneously with an 27^{27}Al+^+ ancillary ion.Comment: 5 pages, 2 figure

    Mathematical optimisation of drainage and economic land use for target water and salt yields

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    Land managers in upper catchments are being asked to make expensive changes in land use, such as by planting trees, to attain environmental service targets, including reduced salt loads in rivers, to meet needs of downstream towns, farms and natural habitats. End-of-valley targets for salt loads have sometimes been set without a quantitative model of cause and effect regarding impacts on water yields, economic efficiency or distribution of costs and benefits among stakeholders. This paper presents a method for calculating a ‘menu’ of technically feasible options for changes from current to future mean water yields and salt loads from upstream catchments having local groundwater flow systems, and the land-use changes to attain each of these options at minimum cost. It sets the economic stage for upstream landholders to negotiate with downstream parties future water-yield and salt-load targets, on the basis of what it will cost to supply these ecosystem services.discounting, landuse, NPV, opportunity-cost, salinity, Resource /Energy Economics and Policy,

    The me in memory:the role of the self in autobiographical memory development

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    This paper tests the hypothesis that self development plays a role in the offset of childhood amnesia; assessing the importance of both the capacity to anchor a memory to the self-concept, and the strength of the self-concept as an anchor. We demonstrate for the first time that the volume of 3- to 6-year-old’s specific autobiographical memories is predicted by both the volume of their self-knowledge, and their capacity for self-source monitoring within self-referencing paradigms (N =186). Moreover, there is a bidirectional relationship between self and memory, such that autobiographical memory mediates the link between self-source monitoring and self-knowledge. These predictive relationships suggests that the self memory system is active in early childhood

    Disposition of precipitation: Supply and Demand for Water Use by New Tree Plantations

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    As the greatest rainwater users among all vegetative land covers, tree plantations have been employed strategically to mitigate salinity and water-logging problems. However, large-scale commercial tree plantations in high rainfall areas reduce fresh water inflows to river systems supporting downstream communities, agricultural industries and wetland environmental assets. A bio-economic model was used to estimate economic demand for water by future upstream plantations in a sub-catchment (the 2.8 million ha Macquarie valley in NSW) of the Murray-Darling Basin, Australia. Given four tree-product values, impacts were simulated under two settings: without and with the requirement that permanent water entitlements be purchased from downstream entitlement holders before establishing a tree plantation. Without this requirement, gains in economic surplus from expanding tree plantations exceeded economic losses by downstream irrigators, and stock and domestic water users, but resulted in reductions of up to 154 GL (gigalitres) in annual flows to wetland environments. With this requirement, smaller gains in upstream economic surplus, added to downstream gains, could total $330 million while preserving environmental flows. Extending downstream water markets to new upstream tree plantations, to equilibrate marginal values across water uses, helps ensure water entitlements are not diminished without compensation. Outcomes include better economic-efficiency, social-equity and environmental-sustainability.Environmental Economics and Policy, forest, environmental services, catchment, water sources, interception, entitlement, supply, demand, market, economic surplus, evapo-transpiration, urban water, irrigation, wetlands.,

    Science Education for Citizenship and a Sustainable Future

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    In this article Jerry Wellington argues very strongly in favour of the role of science in citizenship education. He emphasizes the need for knowledge, skills and action and suggests areas and ways in which pupils can be engaged in the struggle for a sustainable future where interdependence and interconnectedness mesh well with notions of equity and justice
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