4,755 research outputs found

    Making Poverty History? How Activists, Philanthropists, and the Public Are Changing Global Development

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    From August 1 to 3, 2007, fifty preeminent U.S. and international experts from government, business, academia, and the philanthropic and nonprofit sectors came together at the Aspen Institute to explore the changing contours of the global development community. By examining the common challenges development actors face -- promoting accountability, using resources effectively, and achieving scale and sustainability -- participants aimed to spur successful practices and establish foundations for collaboration among the expanding field of players determined to lift the lives of the world's poorest people

    Real-time dynamic holographic image storage device

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    A real-time dynamic holographic image storage device uses four-wave mixing in a pair of photorefractive crystals. An oscillation is produced between the crystals which can be maintained indefinitely after the initial object beam is discontinued. The object beam produces an interference pattern in a first crystal to produce phase-conjugated object beam which is directed towards the second crystal. In the second crystal another interference pattern is created which produces a reconstructed object beam. The reconstructed object beam is directed back towards the first crystal. The interference patterns are produced by interaction of the object and phase-conjugated object beam with a read and write beam in each of the crystals. By manipulation of the ratio of the read and write beam intensities in at least one of the crystals, the phase-conjugate or reconstructed object beam output therefrom can be amplified to maintain stable oscillation between the two crystals

    Plasma control by modification of helicon wave propagation in low magnetic fields

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    By making use of nonuniform magnetic fields, it is shown experimentally that control of helicon wave propagation can be achieved in a low pressure (0.08 Pa) expanding plasma. The m=1 helicon waves are formed during a direct capacitive to wave mode transition that occurs in a low diverging magnetic field(B₀<3 mT). In this initial configuration, waves are prevented from reaching the downstream region, but slight modifications to the magnetic field allows the axial distance over which waves can propagate to be controlled. By changing the effective propagation distance in this way, significant modification of the density and plasma potential profiles can be achieved, showing that the rf power deposition can be spatially controlled as well. Critical to the modification of the wave propagation behavior is the magnetic field strength (and geometry) near the exit of the plasma source region, which gives electron cyclotron frequencies close to the wave frequency of 13.56 MHz

    Recent Performance of the Canadian Economy: A Regional View

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    This article first outlines the activities of the Bank's regional offices and looks at how regional economic analysis fits into the Bank's decision-making process. The changing role of the regional offices in communications and in information gathering is examined, focusing on the quarterly surveys of industries and associations. The second section reviews, from a regional perspective, economic developments since the Asian crisis and future prospects.

    Detailed plasma potential measurements in a radio-frequency expanding plasma obtained from various electrostatic probes

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    On-axis plasma potential measurements have been made with an emissive probe in a low pressure (0.044 Pa) rf expanding plasma containing an ion beam. The beam is detected with a retarding field energy analyzer (RFEA), and is seen to disappear at high pressure (0.39 Pa). The emissive probe measurements are in very good agreement with corresponding measurements made with two separate RFEAs, and the results indicate that the floating potential of the strongly emitting probe gives an accurate measure of the plasma potential under the present conditions

    Interplay between finite resources and local defect in an asymmetric simple exclusion process

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    When particle flux is regulated by multiple factors such as particle supply and varying transport rate, it is important to identify the respective dominant regimes. We extend the well-studied totally asymmetric simple exclusion model to investigate the interplay between a controlled entrance and a local defect site. The model mimics cellular transport phenomena where there is typically a finite particle pool and non-uniform moving rates due to biochemical kinetics. Our simulations reveal regions where, despite an increasing particle supply, the current remains constant while particles redistribute in the system. Exploiting a domain wall approach with mean-field approximation, we provide a theoretical ground for our findings. The results in steady state current and density profiles provide quantitative insights into the regulation of the transcription and translation process in bacterial protein synthesis. We investigate the totally asymmetric simple exclusion model with controlled entrance and a defect site in the bulk to mimic the finite particle pool and non-uniform moving rates in particle transport processes.Comment: 9 pages, 12 figures; v2: minor format changes; v3: major revision, additional references; v4: minor format change to figures, additional reference

    Dollarization in Canada: An Update

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    The authors describe a special survey of the payment and financial-reporting practices of Canadian firms conducted by the Bank of Canada's regional offices to determine if the U.S. dollar has started to displace the Canadian dollar as a preferred unit of account. A cross-section of firms was asked what currency (or currencies) they used: (i) for quoting sales to Canadian customers, (ii) for quoting prices to foreigners, (iii) for reporting their financial results, and (iv) for quoting salaries and wages. The survey results reported here extend some earlier results reported in a previous Review article by Murray and Powell. The data indicate that, despite the dominance of the U.S. dollar in world trade and as an international standard of value, use of the U.S. dollar in Canada is very limited. The vast majority of Canadian firms price their products and keep their financial statements in Canadian dollars, and very few workers in Canada have their salaries paid in a foreign currency. The Canadian dollar is still strongly preferred for most pricing and financial-reporting activities in Canada, and there is very little evidence of "dollarization."

    The Beacon Community Centers Middle School Initiative: Final Report on Implementation and Youth Experience in the Initiative

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    The report evaluates New York City's Beacon Middle School Initiative, which was launched to increase services to middle-grades youth through programs in academics, life skills, career awareness, civic engagement, physical health, and arts and culture. The report describes youth characteristics and participation, program features, connections to school and communities, youth reports of their experiences, and relationships between program characteristics and youth outcomes
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