217 research outputs found
Filling a silo with a mixture of grains: Friction-induced segregation
We study the filling process of a two-dimensional silo with inelastic
particles by simulation of a granular media lattice gas (GMLG) model. We
calculate the surface shape and flow profiles for a monodisperse system and we
introduce a novel generalization of the GMLG model for a binary mixture of
particles of different friction properties where, for the first time, we
measure the segregation process on the surface. The results are in good
agreement with a recent theory, and we explain the observed small deviations by
the nonuniform velocity profile.Comment: 10 pages, 5 figures, to be appear in Europhys. Let
F.A.R.O.G. FORUM, Vol. 2 No. 5
https://digitalcommons.library.umaine.edu/francoamericain_forum/1005/thumbnail.jp
Dynamics of Counterion Condensation
Using a generalization of the Poisson-Boltzmann equation, dynamics of
counterion condensation is studied. For a single charged plate in the presence
of counterions, it is shown that the approach to equilibrium is diffusive. In
the far from equilibrium case of a moving charged plate, a dynamical counterion
condensation transition occurs at a critical velocity. The complex dynamic
behavior of the counterion cloud is shown to lead to a novel nonlinear
force-velocity relation for the moving plate.Comment: 5 pages, 1 ps figure included using eps
First- and second-order transitions of the escape rate in ferrimagnetic or antiferromagnetic particles
Quantum-classical escape-rate transition has been studied for two general
forms of magnetic anisotropy in ferrimagnetic or antiferromagnetic particles.
It is found that the range of the first-order transition is greatly reduced as
the system becomes ferrimagnetic and there is no first-order transition in
almost compensated antiferromagnetic particles. These features can be tested
experimentally in nanomagnets like molecular magnets.Comment: 11 pages, 3 figures, to appear in Europhys. Let
Mie resonances and bonding in photonic crystals
Isolated dielectric spheres support resonant electromagnetic modes which are
analogous to electronic orbitals and, like their electronic counterparts, can
form bonding or anti-bonding interactions between neighbouring spheres. By
irradiating the system with light at the bonding frequency an attractive
interaction is induced between the spheres. We suggest that by judicious
selection of bonding states we can drive a system towards a desired structure,
rather than rely on the structure dictated by gravitational or Van der Waals
forces, the latter deriving from the zero point energy population of a state.Comment: Minor changes in text, of explanatory nature. 6 pages, Latex, 6
figures, accepted by Europhysics Letter
Admission to the Bar: A Constitutional Analysis
This Special Project examines and analyzes selected constitutional challenges to requirements for permanent and temporary admission to the bar. In the area of permanent admission, the Special Project looks at constitutional challenges to three qualifications typically required of bar applicants by states: demonstration of good moral character, successful completion of a bar examination, and residency. In the area of admission pro hac vice , the Project examines constitutional challenges to the basis on which judges have denied temporary admission to an applicant
PT-symmetric deformations of Calogero models
We demonstrate that Coxeter groups allow for complex PT-symmetric deformations across the boundaries of all Weyl chambers. We compute the explicit deformations for the A2 and G2-Coxeter group and apply these constructions to Calogero–Moser–Sutherland models invariant under the extended Coxeter groups. The eigenspectra for the deformed models are real and contain the spectra of the undeformed case as subsystems
Low-Temperature Dephasing in Disordered Conductors: the Effect of ``1/f'' Fluctuations
Electronic quantum effects in disordered conductors are controlled by the
dephasing rate of conduction electrons. This rate is expected to vanish with
the temperature. We consider the very intriguing recently reported apparent
saturation of this dephasing rate in several systems at very low temperatures.
We show that the ``standard model'' of a conductor with static defects can {\em
not} have such an effect. However, allowing some dynamics of the defects may
produce it.Comment: 6page
Transgenic Expression of the Anti-parasitic Factor TEP1 in the Malaria Mosquito Anopheles gambiae
Mosquitoes genetically engineered to be resistant to Plasmodium parasites represent a promising novel approach in the fight against malaria. The insect immune system itself is a source of anti-parasitic genes potentially exploitable for transgenic designs. The Anopheles gambiae thioester containing protein 1 (TEP1) is a potent anti-parasitic protein. TEP1 is secreted and circulates in the mosquito hemolymph, where its activated cleaved form binds and eliminates malaria parasites. Here we investigated whether TEP1 can be used to create malaria resistant mosquitoes. Using a GFP reporter transgene, we determined that the fat body is the main site of TEP1 expression. We generated transgenic mosquitoes that express TEP1r, a potent refractory allele of TEP1, in the fat body and examined the activity of the transgenic protein in wild-type or TEP1 mutant genetic backgrounds. Transgenic TEP1r rescued loss-of-function mutations, but did not increase parasite resistance in the presence of a wild-type susceptible allele. Consistent with previous reports, TEP1 protein expressed from the transgene in the fat body was taken up by hemocytes upon a challenge with injected bacteria. Furthermore, although maturation of transgenic TEP1 into the cleaved form was impaired in one of the TEP1 mutant lines, it was still sufficient to reduce parasite numbers and induce parasite melanization. We also report here the first use of Transcription Activator Like Effectors (TALEs) in Anopheles gambiae to stimulate expression of endogenous TEP1. We found that artificial elevation of TEP1 expression remains moderate in vivo and that enhancement of endogenous TEP1 expression did not result in increased resistance to Plasmodium. Taken together, our results reveal the difficulty of artificially influencing TEP1-mediated Plasmodium resistance, and contribute to further our understanding of the molecular mechanisms underlying mosquito resistance to Plasmodium parasites
Transgenic Expression of the Anti-parasitic Factor TEP1 in the Malaria Mosquito Anopheles gambiae
Mosquitoes genetically engineered to be resistant to Plasmodium parasites represent a promising novel approach in the fight against malaria. The insect immune system itself is a source of anti-parasitic genes potentially exploitable for transgenic designs. The Anopheles gambiae thioester containing protein 1 (TEP1) is a potent anti-parasitic protein. TEP1 is secreted and circulates in the mosquito hemolymph, where its activated cleaved form binds and eliminates malaria parasites. Here we investigated whether TEP1 can be used to create malaria resistant mosquitoes. Using a GFP reporter transgene, we determined that the fat body is the main site of TEP1 expression. We generated transgenic mosquitoes that express TEP1r, a potent refractory allele of TEP1, in the fat body and examined the activity of the transgenic protein in wild-type or TEP1 mutant genetic backgrounds. Transgenic TEP1r rescued loss-of-function mutations, but did not increase parasite resistance in the presence of a wild-type susceptible allele. Consistent with previous reports, TEP1 protein expressed from the transgene in the fat body was taken up by hemocytes upon a challenge with injected bacteria. Furthermore, although maturation of transgenic TEP1 into the cleaved form was impaired in one of the TEP1 mutant lines, it was still sufficient to reduce parasite numbers and induce parasite melanization. We also report here the first use of Transcription Activator Like Effectors (TALEs) in Anopheles gambiae to stimulate expression of endogenous TEP1. We found that artificial elevation of TEP1 expression remains moderate in vivo and that enhancement of endogenous TEP1 expression did not result in increased resistance to Plasmodium. Taken together, our results reveal the difficulty of artificially influencing TEP1-mediated Plasmodium resistance, and contribute to further our understanding of the molecular mechanisms underlying mosquito resistance to Plasmodium parasites
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