1,887 research outputs found

    Time Budget on Major Activities of Livestock Grazing Heterogeneous Natural Range and Crop Fields in Semi-Arid Nigeria

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    Semi-arid rangelands of West Africa provide herbs, trees and shrubs, which together with crop residues form the main sources of feed for the livestock population. Feed supply in this region is characterised by a progressive decline in quantity and quality with advancing dry season. It was reported that walking ability as well as watering frequencies affect the productivity of grazing livestock (Dicko and Sangare, 1984). This study tests the hypothesis that advancing season increases both time spent walking as well as feeding, with a switch from grazing to browsing

    Fast extracted proton beams at low energies in the CPS east experimental area

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    To provide beams with characteristics required by the Energy Amplifier Test, the CERN PS had to deliver new beams, of low kinetic energy (0.6 - 2.7 GeV), low intensity (0.5-5¥109p) and short duration (<500 ns) via the existing slow extraction channel, the transfer line currently used for 24 GeV/c beams and a slightly modified secondary line. These beams were delivered without impairing other CPS operations and, despite large operational differences, the other three East area beam lines could alternatively be supplied with slow extracted beam, for half week periods, thanks to the short setting-up time of a few hours. This paper describes how such beams were produced: by (i) acceleration or deceleration of the injected beam in the CPS, depending on the requested energy, (ii) fast extraction using the usual slow extraction channel, (iii) careful optics adjustments and reduction of multiple scattering in the transfer line. The range of beam characteristics achieved, as well as the limitations encountered are also reported

    Nonuniversal Shot Noise in Disordered Quantum Wires with Channel-Number Imbalance

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    The number of conducting channels for one propagating direction is equal to that for the other direction in ordinary quantum wires. However, they can be imbalanced in graphene nanoribbons with zigzag edges. Employing the model system in which a degree of channel-number imbalance can be controlled, we calculate the shot-noise power at zero frequency by using the Boltzmann-Langevin approach. The shot-noise power in an ordinary diffusive conductor is one-third of the Poisson value. We show that with increasing the degree of channel-number imbalance, the universal one-third suppression breaks down and a highly nonuniversal behavior of shot noise appears.Comment: 10 pages, 3 figure

    Phase field analysis of eutectic breakdown.

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    In this paper an isotropic multi-phase-field model is extended to include the effects of anisotropy and the spontaneous nucleation of an absent phase. This model is derived and compared against a published single phase model. Results from this model are compared against results from other multi-phase models, additionally this model is used to examine the break down of a regular two dimensional eutectic into a single phase dendritic front

    Identification and mutational analyses of phosphorylation sites of the calcineurin-binding protein CbpA and the identification of domains required for calcineurin binding in Aspergillus fumigatus.

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    Calcineurin is a key protein phosphatase required for hyphal growth and virulence in Aspergillus fumigatus, making it an attractive antifungal target. However, currently available calcineurin inhibitors, FK506 and cyclosporine A, are immunosuppressive, limiting usage in the treatment of patients with invasive aspergillosis. Therefore, the identification of endogenous inhibitors of calcineurin belonging to the calcipressin family is an important parallel strategy. We previously identified the gene cbpA as the A. fumigatus calcipressin member and showed its involvement in hyphal growth and calcium homeostasis. However, the mechanism of its activation/inhibition through phosphorylation and its interaction with calcineurin remains unknown. Here we show that A. fumigatus CbpA is phosphorylated at three distinct domains, including the conserved SP repeat motif (phosphorylated domain-I; PD-I), a filamentous fungal-specific domain (PD-II), and the C-terminal CIC motif (Calcipressin Inhibitor of Calcineurin; PD-III). While mutation of three phosphorylated residues (Ser208, Ser217, Ser223) in the PD-II did not affect CbpA function in vivo, mutation of the two phosphorylated serines (Ser156, Ser160) in the SP repeat motif caused reduced hyphal growth and sensitivity to oxidative stress. Mutational analysis in the key domains in calcineurin A (CnaA) and proteomic interaction studies confirmed the requirement of PxIxIT motif-binding residues (352-NIR-354) and the calcineurin B (CnaB)-binding helix residue (V371) for the binding of CbpA to CnaA. Additionally, while the calmodulin-binding residues (442-RVF-444) did not affect CbpA binding to CnaA, three mutations (T359P, H361L, and L365S) clustered between the CnaA catalytic and the CnaB-binding helix were also required for CbpA binding. This is the first study to analyze the phosphorylation status of calcipressin in filamentous fungi and identify the domains required for binding to calcineurin

    Exploiting Chordality in Optimization Algorithms for Model Predictive Control

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    In this chapter we show that chordal structure can be used to devise efficient optimization methods for many common model predictive control problems. The chordal structure is used both for computing search directions efficiently as well as for distributing all the other computations in an interior-point method for solving the problem. The chordal structure can stem both from the sequential nature of the problem as well as from distributed formulations of the problem related to scenario trees or other formulations. The framework enables efficient parallel computations.Comment: arXiv admin note: text overlap with arXiv:1502.0638

    Effect of screening on shot noise in diffusive mesoscopic conductors

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    Shot noise in diffusive mesoscopic conductors, at finite observation frequencies ω\omega (comparable to the reciprocal Thouless time τT1\tau_T^{-1}), is analyzed with an account of screening. At low frequencies, the well-known result SI(ω)=2eI/3S_I(\omega)=2eI/3 is recovered. This result is valid at arbitrary ωτT\omega \tau_T for wide conductors longer than the screening length. However, at least for two very different systems, namely, wide and short conductors, and thin conductors over a close ground plane, noise approaches a different fundamental level, SI(ω)=eIS_I(\omega) = eI, at ωτT1\omega \tau _T\gg 1.Comment: 5 pages, 3 figures. Published version. Also available in the journal's format at http://hana.physics.sunysb.edu/~yehuda/cv/papers/shotnoise.pd

    A quantum phase gate implementation for trapped ions in thermal motion

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    We propose a novel scheme to implement a quantum controlled phase gate for trapped ions in thermal motion with one standing wave laser pulse. Instead of applying the rotating wave approximation this scheme makes use of the counter-rotating terms of operators. We also demonstrate that the same scheme can be used to generate maximally entangled states of NN trapped ions by a single laser pulse
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