6,562 research outputs found
Viscoelastic evaluation of biological soft tissue in crush process at subsonic level for anti-bird strike technology of airplane
Miniaturization and lightening of airplane are advanced to improve its economic efficiency, and the safety technology of airplane design becomes difficult while the accident of bird-strike is increasing year by year. Then a system of shock impact test by using airsoft rifle is developed to evaluate the design technology of anti-bird strike structure of airplane. The viscoelastic characteristics of specimen is evaluated by analyzing stress response using the modified Hertz contact theory and the wave equation at the moment when simple ball bullet is shot to specimen by the airsoft rifle. In the results of experiment, the obvious relationship is observed subjectively between quasi-static and impact responses of specimen. The evaluated viscoelastic relationship is applied to simulate the impact test by using LSDYNA with fundamental viscoelastic constitutive equation and the material parameters derived from the impact test, and the well similar behavior has been simulated by the constitutive equation. By using the developed technology here, the phantom imitating real bird will be developed as standard specimen for an anti-bird strike test in future
Spin-polarized electronic structures and transport properties of Fe-Co alloys
The electrical resistivities of Fe-Co alloys owing to random alloy disorder
are calculated using the Kubo-Greenwood formula. The obtained electrical
esistivities agree well with experimental data quantitatively at low
temperature. The spin-polarization of Fe50Co50 estimated from the conductivity
(86%) has opposite sign to that from the densities of the states at the Fermi
level (-73%). It is found that the conductivity is governed mainly by
s-electrons, and the s-electrons in the minority spin states are less
conductive due to strong scattering by the large densities of the states of
d-electrons than the majority spin electrons.Comment: 3 pages, 4 figure
Nuclear pore complex-mediated modulation of TCR signaling is required for naïve CD4+ T cell homeostasis.
Nuclear pore complexes (NPCs) are channels connecting the nucleus with the cytoplasm. We report that loss of the tissue-specific NPC component Nup210 causes a severe deficit of naïve CD4+ T cells. Nup210-deficient CD4+ T lymphocytes develop normally but fail to survive in the periphery. The decreased survival results from both an impaired ability to transmit tonic T cell receptor (TCR) signals and increased levels of Fas, which sensitize Nup210-/- naïve CD4+ T cells to Fas-mediated cell death. Mechanistically, Nup210 regulates these processes by modulating the expression of Cav2 (encoding Caveolin-2) and Jun at the nuclear periphery. Whereas the TCR-dependent and CD4+ T cell-specific upregulation of Cav2 is critical for proximal TCR signaling, cJun expression is required for STAT3-dependent repression of Fas. Our results uncover an unexpected role for Nup210 as a cell-intrinsic regulator of TCR signaling and T cell homeostasis and expose NPCs as key players in the adaptive immune system
GW approximation with self-screening correction
The \emph{GW} approximation takes into account electrostatic self-interaction
contained in the Hartree potential through the exchange potential. However, it
has been known for a long time that the approximation contains self-screening
error as evident in the case of the hydrogen atom. When applied to the hydrogen
atom, the \emph{GW} approximation does not yield the exact result for the
electron removal spectra because of the presence of self-screening: the hole
left behind is erroneously screened by the only electron in the system which is
no longer present. We present a scheme to take into account self-screening and
show that the removal of self-screening is equivalent to including exchange
diagrams, as far as self-screening is concerned. The scheme is tested on a
model hydrogen dimer and it is shown that the scheme yields the exact result to
second order in where and are respectively
the onsite and offsite Hubbard interaction parameters and the hopping
parameter.Comment: 9 pages, 2 figures; Submitted to Phys. Rev.
Dijet Cross Section and Longitudinal Double Spin Asymmetry Measurements in Polarized Proton-proton Collisions at \sqrt{s}=200 GeV at STAR
These proceedings show the preliminary results of the dijet cross sections
and the dijet longitudinal double spin asymmetries A_LL in polarized
proton-proton collisions at \sqrt{s} = 200 GeV at the mid-rapidity |eta| < 0.8.
The integrated luminosity of 5.39 pb^{-1} collected during RHIC Run-6 was used
in the measurements. The preliminary results are presented as functions of the
dijet invariant mass M_jj. The dijet cross sections are in agreement with
next-to-leading-order pQCD predictions. The A_LL is compared with theoretical
predictions based on various parameterizations of polarized parton
distributions of the proton. Projected precision of data analyzed to date from
Run-9 are shown.Comment: 8 pages, 5 figures, Proceedings of the SPIN2010 conference (Juelich,
Germany, 2010
Defining a Health Benefits Package: What Are the Necessary Processes?
There is immense interest worldwide in the notion of universal health coverage (UHC). A major policy focus in moving toward UHC has been on the key policy question: what services should be made available and under what conditions? In this article we are concerned with how a feasible set of UHC services can be explicitly defined to create what is commonly known as a “health benefits package” (HBP), a set of services that can be feasibly financed and provided under the actual circumstances in which a given country finds itself. We explain why an explicit statement of the HBP is important and then describe a framework that includes ten core elements that are indispensable if a coherent and sustainable process for setting the HBP is to be established
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