4,867 research outputs found

    Funding the Future: Resources for Adolescent Reproductive and Sexual Health Programs in Developing Countries

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    Provides a directory of over 90 foundations, agencies, and organizations that support adolescent reproductive and sexual health related programs in developing countries, through direct and/or indirect financing, technical assistance, and information

    ENVIRONMENTAL AND ECONOMIC IMPACTS OF AGRICULTURAL POLICY REFORM: AN INTERREGIONAL COMPARISON

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    Mathematical programming results revealed that moving toward more flexible agricultural policies would generate substantial economic and environmental gains in a North Carolina diversified cropping region. But in a Washington-Idaho dryland grains region, only the use of relatively new and sometimes problematic alternative cropping systems permitted environmental and economic gains under policy reform. In both regions, a recoupling policy, which links government payments to resource-conserving farming practices, was needed to protect environmental quality when market prices for program crops were high.Agrichemical leaching, Agricultural policy, Alternative agriculture, Erosion, Mathematical programming, Agricultural and Food Policy,

    A review of the Genus Hyperalonia Rondani (Bombyliidae, Diptera) from South América

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    Optomechanical creation of magnetic fields for photons on a lattice

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    We propose using the optomechanical interaction to create artificial magnetic fields for photons on a lattice. The ingredients required are an optomechanical crystal, i.e. a piece of dielectric with the right pattern of holes, and two laser beams with the right pattern of phases. One of the two proposed schemes is based on optomechanical modulation of the links between optical modes, while the other is an lattice extension of optomechanical wavelength-conversion setups. We illustrate the resulting optical spectrum, photon transport in the presence of an artificial Lorentz force, edge states, and the photonic Aharonov-Bohm effect. Moreover, wWe also briefly describe the gauge fields acting on the synthetic dimension related to the phonon/photon degree of freedom. These can be generated using a single laser beam impinging on an optomechanical array

    Photonic Crystals and their Applications to Efficient Light Emitters

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    When combined with high index contrast slabs in which light can be efficiently guided, microfabricated two-dimensional photonic bandgap mirrors provide us with the geometries needed to confine and concentrate light into extremely small volumes and to obtain very high field intensities. Fabrication of optical structures has now evolved to a precision which allows us to control light within such etched nanostructures. Sub-wavelength nano-optic cavities can be used for efficient and flexible control over both emission wavelength and frequency, and nanofabricated optical waveguides can be used for efficient coupling of light between devices. The reduction of the size of optical components leads to their integration in large numbers and the possibility to combine different functionalities on a single chip. We show uses of such crystals in functional nonlinear optical devices, such as lasers, modulators, add/drop filters, polarizers and detectors
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