26,506 research outputs found

    Study of dominating parameters of high speed solar plasma streams in relation to cosmic ray and geomagnetic storms

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    The high speed solar wind streams observed near Earth are generally associated with the solar features, such as solar flares and coronal holes. Past studies of these streams from the two sources have revealed distinctly different effects on cosmic ray intensity, whereas the effect is similar for geomagnetic disturbances. Moreover, the effect of the magnitude of the high speed streams (V) and its rate of increase (dv/dt) has also been a subject of investigation to understand their relative contribution in producing geomagnetic disturbances. From the analysis of some of the fast streams presented here, it is difficult to predict, which one of the two (V, dv/dt) is more effective in producing geo-magnetic disturbances. Further, in most of the cases, no substantial decrease in cosmic ray intensity is observed

    Saturated-Unsaturated flow in a Compressible Leaky-unconfined Aquifer

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    An analytical solution is developed for three-dimensional flow towards a partially penetrating large-diameter well in an unconfined aquifer bounded below by an aquitard of finite or semi-infinite extent. The analytical solution is derived using Laplace and Hankel transforms, then inverted numerically. Existing solutions for flow in leaky unconfined aquifers neglect the unsaturated zone following an assumption of instantaneous drainage assumption due to Neuman [1972]. We extend the theory of leakage in unconfined aquifers by (1) including water flow and storage in the unsaturated zone above the water table, and (2) allowing the finite-diameter pumping well to partially penetrate the aquifer. The investigation of model-predicted results shows that leakage from an underlying aquitard leads to significant departure from the unconfined solution without leakage. The investigation of dimensionless time-drawdown relationships shows that the aquitard drawdown also depends on unsaturated zone properties and the pumping-well wellbore storage effects

    Qubit(s) transfer in helical spin chains

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    Qubit(s) transfer through a helical chain is studied. We consider the transfer of a single state and Bell states across a multiferroic spin chain and the possibility of an electric field control of the fidelity of the single state and the Bell pairs. We analyze pure and imperfect multiferroic spin chains. A scheme for an efficient transfer of spin states through a multiferroic channel relies on kicking by appropriate electric field pulses at regular interval. This electric field pulse sequence undermines the effect of impurity on the fidelity and improves the state transfer through the helical chain.Comment: 7 pages, 10 figure

    Chiral Symmetry Breaking and Pion Wave Function

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    We consider here chiral symmetry breaking through nontrivial vacuum structure with quark antiquark condensates. We then relate the condensate function to the wave function of pion as a Goldstone mode. This simultaneously yields the pion also as a quark antiquark bound state as a localised zero mode in vacuum. We illustrate the above with Nambu Jona-Lasinio model to calculate different pionic properties in terms of the vacuum structure for breaking of exact or approximate chiral symmetry, as well as the condensate fluctuations giving rise to σ\sigma mesons.Comment: latex, revtex, 16 page

    The Impact of Participation in Cooperatives on the Success of Small Farms

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    This study identifies and analyzes factors that contribute to the success of small farms. Particular attention is given to the effect of participation in marketing and supply cooperatives on the success of small farms. Using modified net farm income per dollar of assets and operator’s labor and management income as measures of success, results show participation in marketing and supply cooperatives is positively correlated with success. Further, analysis findings indicate farm size, controlling for variable and fixed costs, type of ownership, management strategies used, working off the farm, and age of the operator are important factors that influence profitability (modified net farm income per dollar of assets and operator’s labor and management income) and success.cooperatives, management strategies, marketing, small farms, success, supply cooperative, Agribusiness, Marketing,
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