53,248 research outputs found

    Water, women and local social organization in the Western Kenya highlands

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    Safe water is widely recognized as both a fundamental human need and a key input into economic activity. Across the developing world, the typical approach to addressing these needs is to segregate supplies of water for domestic use from water for large-scale agricultural production. In that arrangement, the goal of domestic water supply is to provide small amounts of clean safe water for direct consumption, cleaning, bathing and sanitation, while the goal of agricultural water supply is to provide large amounts of lower quality water for irrigated agriculture. A new third use of water is now being given more attention by researchers: small amounts of water employed in selected household enterprises. This third use may be particularly important for women. There is a potential, therefore, that provision of modest amounts of water to smallholder farmers can enhance household economic production, save labor time for women and girls, and improve family health. This paper adds to the merger literature on the multiple values of improved water supplies – improved health, time savings, and small-scale production for individual farmers and collectives – for the case of a rural community in the western highlands of Kenya. With minimum external support, two groups in this community have managed to install and operate systems of spring protection and piped water to their members’ homesteads. A third group is in the process of replicating this success. The experience of this community also illustrates some of the challenges that must be faced for a community to effectively selforganize the investment and maintenance of a community-based water scheme. There are challenges of finance, gender relations, conflicts over scarce water supplies, group leadership, enforcement of community bi-laws, and policy. Data from a census of springs in the same area show that successful collective action for water management is unusual, but certainly not unique, in this region of Kenya. Although women emerge as the main beneficiaries of improved water management in the community, their substantial contributions are largely hidden behind social norms regarding gender roles and relations. Research methods need to carefully triangulate information sources in order to clarify the very substantial and active roles performed by women.Length: 21p.WomenGenderWater supplyWater rightsHealthCollective actionParticipatory management

    Dissociation energy and long-range potential of diatomic molecules from vibrational spacings - The halogens

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    Dissociation energy and long-range potential of diatomic molecules from vibrational spacings, halogen

    Ab initio yield curve dynamics

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    We derive an equation of motion for interest-rate yield curves by applying a minimum Fisher information variational approach to the implied probability density. By construction, solutions to the equation of motion recover observed bond prices. More significantly, the form of the resulting equation explains the success of the Nelson Siegel approach to fitting static yield curves and the empirically observed modal structure of yield curves. A practical numerical implementation of this equation of motion is found by using the Karhunen-Loeve expansion and Galerkin's method to formulate a reduced-order model of yield curve dynamics.Comment: 11 LateX pages, 2 figure

    Shape resonances and rotationally predissociating levels - The atomic collision time delay functions and quasibound level properties of H2 /Chi /1 Sigma g plus//

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    Atomic collision time delay functions and quasibound level properties of ground state of molecular hydroge

    Graphene as a Novel Single Photon Counting Optical and IR Photodetector

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    Bilayer graphene has many unique optoelectronic properties , including a tuneable band gap, that make it possible to develop new and more efficient optical and nanoelectronic devices. We have developed a Monte Carlo simulation for a single photon counting photodetector incorporating bilayer graphene. Our results show that, conceptually it would be feasible to manufacture a single photon counting photodetector (with colour sensitivity) from bilayer graphene for use across both optical and infrared wavelengths. Our concept exploits the high carrier mobility and tuneable band gap associated with a bilayer graphene approach. This allows for low noise operation over a range of cryogenic temperatures, thereby reducing the cost of cryogens with a trade off between resolution and operating temperature. The results from this theoretical study now enable us to progress onto the manufacture of prototype photon counters at optical and IR wavelengths that may have the potential to be groundbreaking in some scientific research applications.Comment: Conference Proceeding in Graphene-Based Technologies, 201

    A constrained pressure-temperature residual (CPTR) method for non-isothermal multiphase flow in porous media

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    For both isothermal and thermal petroleum reservoir simulation, the Constrained Pressure Residual (CPR) method is the industry-standard preconditioner. This method is a two-stage process involving the solution of a restricted pressure system. While initially designed for the isothermal case, CPR is also the standard for thermal cases. However, its treatment of the energy conservation equation does not incorporate heat diffusion, which is often dominant in thermal cases. In this paper, we present an extension of CPR: the Constrained Pressure-Temperature Residual (CPTR) method, where a restricted pressure-temperature system is solved in the first stage. In previous work, we introduced a block preconditioner with an efficient Schur complement approximation for a pressure-temperature system. Here, we extend this method for multiphase flow as the first stage of CPTR. The algorithmic performance of different two-stage preconditioners is evaluated for reservoir simulation test cases.Comment: 28 pages, 2 figures. Sources/sinks description in arXiv:1902.0009

    Kinetic arrest of the first order ferromagnetic to antiferromagnetic transition in Ce(Fe0.96_{0.96}Ru0.04_{0.04})2_2 : formation of a magnetic-glass

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    We present results of dc magnetization and magnetic relaxation study showing the kinetic arrest of a first order ferromagnetic to antiferromagnetic transition in Ce(Fe0.96_{0.96}Ru0.04_{0.04})2_2. This leads to the formation of a non-ergodic glass-like magnetic state. The onset of the magnetic-glass transformation is tracked through the slowing down of the magnetization dynamics. This glassy state is formed with the assistance of an external magnetic field and this is distinctly different from the well known 'spin-glass' state.Comment: 10 pages of text and 4 figure

    Phases, many-body entropy measures and coherence of interacting bosons in optical lattices

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    Already a few bosons with contact interparticle interactions in small optical lattices feature a variety of quantum phases: superfluid, Mott-insulator and fermionized Tonks gases can be probed in such systems. To detect these phases -- pivotal for both experiment and theory -- as well as their many-body properties we analyze several distinct measures for the one-body and many-body Shannon information entropies. We exemplify the connection of these entropies with spatial correlations in the many-body state by contrasting them to the Glauber normalized correlation functions. To obtain the ground-state for lattices with commensurate filling (i.e. an integer number of particles per site) for the full range of repulsive interparticle interactions we utilize the multiconfigurational time-dependent Hartree method for bosons (MCTDHB) in order to solve the many-boson Schr\"odinger equation. We demonstrate that all emergent phases -- the superfluid, the Mott insulator, and the fermionized gas can be characterized equivalently by our many-body entropy measures and by Glauber's normalized correlation functions. In contrast to our many-body entropy measures, single-particle entropy cannot capture these transitions.Comment: 11 pages, 7 figures, software available at http://ultracold.or
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