13,306 research outputs found
Dynamin recruitment by clathrin coats: a physical step?
Recent structural findings have shown that dynamin, a cytosol protein playing
a key-role in clathrin-mediated endocytosis, inserts partly within the lipid
bilayer and tends to self-assemble around lipid tubules. Taking into account
these observations, we make the hypothesis that individual membrane inserted
dynamins imprint a local cylindrical curvature to the membrane. This imprint
may give rise to long-range mechanical forces mediated by the elasticity of the
membrane. Calculating the resulting many-body interaction between a collection
of inserted dynamins and a membrane bud, we find a regime in which the dynamins
are elastically recruited by the bud to form a collar around its neck, which is
reminiscent of the actual process preempting vesicle scission. This physical
mechanism might therefore be implied in the recruitment of dynamins by clathrin
coats.Comment: 11 pages, 6 figures, to appear in C.R.A.S. ser II
N-body Study of Anisotropic Membrane Inclusions: Membrane Mediated Interactions and Ordered Aggregation
We study the collective behavior of inclusions inducing local anisotropic
curvatures in a flexible fluid membrane. The N-body interaction energy for
general anisotropic inclusions is calculated explicitly, including multi-body
interactions. Long-range attractive interactions between inclusions are found
to be sufficiently strong to induce aggregation. Monte Carlo simulations show a
transition from compact clusters to aggregation on lines or circles. These
results might be relevant to proteins in biological membranes or colloidal
particles bound to surfactant membranes.Comment: 4 pages, 3 figs, LaTe
Distributed upper-surface blowing concept
A low speed investigation was conducted in the Langley V/STOL tunnel to determine the powered lift aerodynamic performance of a distributed upper surface blown propulsive lift transport model. The model used blowing slots across the span of the wing to produce a thin jet efflux near the leading edge and at the knee of the trailing edge flap (internally blown jet flap). Results indicate that these concepts have both good propulsive related lift and low drag due to lift characteristics because of uniform spanwise propulsive thrust. The leading edge blowing concept provides low speed lift characteristics which are competitive with the flap-hinge-line blowing concept and does not require additional leading edge treatment for prevention of abrupt stall
Does Corporate Governance Matter in Deposit Insurance? DI and Moral Hazard in Joint Stock and Mutual Financial Intermediaries
In this paper, we analyze the differences of effects of a deposit insurance schemes on financial cooperative and joint stock banks risk taking. We develop a methodology which includes the specifics of the utility function for the financial cooperative and we compare the results to a similar profit maximizing joint stock bank. We find that the introduction of deposit insurance does in fact increase optimal risk level for the financial cooperative but less so than the stock bank. Thus, corporate governance does matter in the level of risk exposure of a deposit insurance scheme. Further, like in joint stock banks, this moral hazard can be curbed through incentives such as risk adjusted premias, risk adjusted regulatory capital and possibly reserve requirements.
Design aspects of a solar array drive for spot, with a high platform stability objective
A solar array drive mechanism (MEGS) for the SPOT platform, which is a prototype of a multimission platform, is described. High-resolution cameras and other optical instruments are carried by the platform, requiring excellent platform stability in order to obtain high-quality pictures. Therefore, a severe requirement for the MEGS is the low level of disturbing torques it may generate considering the 0.6 times 10 to the minus 3 power deg/sec stability required. The mechanical design aspects aiming at reducing the mean friction torque, and therefore its fluctuations, are described as well as the method of compensation of the motor imperfections. It was concluded, however, that this is not sufficient to reach the stability requirement
Field-dependent diamagnetic transition in magnetic superconductor
The magnetic penetration depth of single crystal
was measured down to 0.4 K in dc fields up
to 7 kOe. For insulating , Sm spins order at the
N\'{e}el temperature, K, independent of the applied field.
Superconducting ( K) shows a
sharp increase in diamagnetic screening below which varied from
4.0 K () to 0.5 K ( 7 kOe) for a field along the c-axis. If the
field was aligned parallel to the conducting planes, remained
unchanged. The unusual field dependence of indicates a spin freezing
transition that dramatically increases the superfluid density.Comment: 4 pages, RevTex
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