1,889 research outputs found
Time Budget on Major Activities of Livestock Grazing Heterogeneous Natural Range and Crop Fields in Semi-Arid Nigeria
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
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
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.
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.
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
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
Stochastic simulations of the quantum Zeno effect
Published versio
Effect of screening on shot noise in diffusive mesoscopic conductors
Shot noise in diffusive mesoscopic conductors, at finite observation
frequencies (comparable to the reciprocal Thouless time
), is analyzed with an account of screening. At low frequencies,
the well-known result is recovered. This result is valid at
arbitrary 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, , at .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
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 trapped ions by a
single laser pulse
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