1,968 research outputs found
Properties of some five dimensional Einstein metrics
The volumes, spectra and geodesics of a recently constructed infinite family
of five-dimensional inhomogeneous Einstein metrics on the two bundles
over are examined. The metrics are in general of cohomogeneity one but
they contain the infinite family of homogeneous metrics . The geodesic
flow is shown to be completely integrable, in fact both the Hamilton-Jacobi and
the Laplace equation separate. As an application of these results, we compute
the zeta function of the Laplace operator on for large . We
discuss the spectrum of the Lichnerowicz operator on symmetric transverse
tracefree second rank tensor fields, with application to the stability of
Freund-Rubin compactifications and generalised black holes.Comment: 1+43 pages, 2 figures, LaTeX. Minor typos correcte
Structural analysis of silicon solar arrays
Engineering mechanics in structural design of silicon solar array
Thermoelastic analysis of solar cell arrays and their material properties
Announced report discusses experimental test program in which five different solar cell array designs were evaluated by subjecting them to 60 thermal cycles from minus 190 deg to 0.0 deg. Results indicate that solder-coated cells combined with Kovar n-interconnectors and p-interconnectors are more durable under thermal loading than other configurations
Mariner Venus 67 solar panel
Design, assembly, tests, and postflight analysis of Mariner Venus 67 solar pane
Spatial and temporal cellular responses to single-strand breaks in human cells
DNA single-strand breaks (SSB) are one of the most frequent DNA lesions produced by reactive oxygen species and during DNA metabolism, but the analysis of cellular responses to SSB remains difficult due to the lack of an experimental method to produce SSB alone in cells. By using human cells expressing a foreign UV damage endonuclease (UVDE) and irradiating the cells with UV through tiny pores in membrane filters, we created SSB in restricted areas in the nucleus by the immediate action of UVDE on UV-induced DNA lesions. Cellular responses to the SSB were characterized by using antibodies and fluorescence microscopy. Upon UV irradiation, poly(ADP-ribose) synthesis occurred immediately in the irradiated area. Simultaneously, but dependent on poly(ADP-ribosyl)ation, XRCC1 was translocated from throughout the nucleus, including nucleoli, to the SSB. The BRCT1 domain of XRCC1 protein was indispensable for its poly(ADP-ribose)-dependent recruitment to the SSB. Proliferating cell nuclear antigen and the p150 subunit of chromatin assembly factor 1 also accumulated at the SSB in a detergent-resistant form, which was significantly reduced by inhibition of poly(ADP-ribose) synthesis. Our results show the importance of poly(ADP-ribosyl)ation in sequential cellular responses to SSB
Chiral symmetry breaking and vacuum polarization in a bag
We study the effects of a finite quark mass in the hedgehog configuration in
the two phase chiral bag model. We discuss the chiral properties, such as the
fractional baryon number and the chiral Casimir energy, by using the Debye
expansion for the analytical calculation and the Strutinsky's smearing method
for the numerical computation. It is shown that the fractional baryon number
carried by massive quarks in the vacuum is canceled by that in the meson
sector. A finite term of the chiral Casimir energy is obtained with subtraction
of the logarithmic divergence term
Chiral symmetry breaking and stability of quark droplets
We discuss the stability of strangelets -- quark droplets with strangeness --
in the Nambu--Jona-Lasinio model supplemented by a boundary condition for quark
confinement. Effects of dynamical chiral symmetry breaking are considered
properly inside quark droplets of arbitrary baryon number. We obtain the energy
per baryon number of quark droplets with baryon number from one to thousands.
It is shown that strangelets are not the ground states as compared with nuclei,
though they can be locally stable
Performance of silicon solar cell assemblies
Solar cell assembly current-voltage characteristics, thermal-optical properties, and power performance were determined. Solar cell cover glass thermal radiation, optical properties, confidence limits, and temperature intensity effects on maximum power were discussed
Boundary Value Problem for Black Rings
We study the boundary value problem for asymptotically flat stationary black
ring solutions to the five-dimensional vacuum Einstein equations. Assuming the
existence of two additional commuting axial Killing vector fields and the
horizon topology of , we show that the only asymptotically flat
black ring solution with a regular horizon is the Pomeransky-Sen'kov black ring
solution.Comment: 21 pages, 1 figur
Are Japanese and European gastric cancer the same biological entity? An immunohistochemical study.
To examine the suggested biological difference between Japanese and British gastric cancers, immunohistochemistry was used to demonstrate eight markers of biological activity in a matched series of 40 Japanese and 33 British cases. There were no differences in the proportions of Japanese and British tumours positive to epidermal growth factor, epidermal growth factor receptor, transforming growth factor alpha, cripto or p53. A significantly greater proportion of British tumours were positive to c-erbB-2 whilst a significantly greater proportion of Japanese tumours were positive to nm23. British tumours had a significantly greater mean proliferating cell nuclear antigen proliferation index than Japanese tumours. These differences could be clinically significant
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