4,342 research outputs found
Colocalization of Transcription and Translation within Cytoplasmic Poxvirus Factories Coordinates Viral Expression and Subjugates Host Functions
SummaryPoxviruses are large DNA viruses that include the causal agent of human smallpox and vaccinia virus. Poxviruses replicate in cytoplasmic foci known as DNA factories. Here we show that a virus-encoded transcription factor, viral mRNA, cellular RNA-binding protein heterodimer G3BP/Caprin-1 (p137), translation initiation factors eIF4E and eIF4G, and ribosomal proteins are concentrated in the same subdomains of cytoplasmic DNA factories. Furthermore, a cell coinfected with two recombinant vaccinia viruses expressing a virus core protein fused to cyan or yellow fluorescent protein displayed separate cyan and yellow factories, indicating that each factory formed from a single genome and was the site of transcription and translation as well as DNA replication. Hijacking of the host translation apparatus within the factory likely enhances the efficiency of virus replication and contributes to the suppression of host protein synthesis, thereby facilitating poxvirus subjugation of the cell
Radioactivities induced in some LDEF samples
Radioactivities induced in several Long Duration Exposure Facilities (LDEF) samples were measured by low-level counting at Los Alamos and elsewhere. These radionuclides have activities similar to those observed in meteorites and lunar samples. Some trends were observed in these measurements in terms of profiles in trunnion layers and as a function of radionuclide half-life. Several existing computer codes were used to model the production by the protons trapped in the Earth's radiation belts and by the galactic cosmic rays of some of these radionuclides, Mn-54 and Co-57 in steel, Sc-46 in titanium, and Na-22 in alloys of titanium and aluminum. Production rates were also calculated for radionuclides possibly implanted in LDEF, Be-7, Be-10, and C-14. Enhanced concentrations of induced isotopes in the surfaces of trunnion sections relative to their concentrations in the center are caused by the lower-energy protons in the trapped radiation. Secondary neutrons made by high-energy trapped protons and by galactic cosmic rays produce much of the observed radioactivities, especially deep in an object. Comparisons of the observed to calculated activities of several radionuclides with different half-lives indicate that the flux of trapped protons at LDEF decreased significantly at the end of the mission
Effects of Domestic Wastewater Effluent on the Water Quality and Aquatic Macroinvertebrates in a Sharp County, Arkansas Stream
The purpose of this study was to determine whether the effluent of the Ash Flat Wastewater Treatment Plant changes the water quality or aquatic macroinvertebrate community structure of North Big Creek. Weekly water samples were analyzed for pH, N, P, COD, TSS and fecal coliform bacteria from 17 June to 19 August 1992. Aquatic macroinvertebrates were collected biweekly using a Turtox Indestructible™ Dip Net, and density indices were calculated. Station 1, above the effluent, was a spring habitat. Fecal coliform, N, P, TSS and COD values were higher at this station, while the aquatic macroinvertebrate community was relatively simple. The effluent impact upon Station 2 was most obvious from the persistent presence of foam and filamentous algae. Moderating water temperature and enhanced nutrient supply has resulted in a more complex aquatic macroinvertebrate community with a lower numerical standing crop
Conformal Anomaly for Free Scalar Propagation on Curved Bounded Manifolds
The trace anomaly for free propagation in the context of a conformally
invariant scalar field theory defined on a curved manifold of positive constant
curvature with boundary is evaluated through use of an asymptotic heat kernel
expansion. In addition to their direct physical significance the results are
also of relevance to the holographic principle and to Quantum Cosmology.Comment: 8 pages. To appear in General Relativity and Gravitatio
1963 VW Beetle--Electric Vehicle Conversion
As the issues with the environment continue to grow, cities around the world are beginning to implement bans on internal combustion engines. This means that older cars and classics will now be confined to a garage or showroom instead of being enjoyed from the driver\u27s seat. Our solution is to convert a classic car to electric by reusing batteries and electric vehicle components. By designing a modular system of adapting these components to a classic car, owners would be able to enjoy their classic cars without the drawbacks of outdated performance and poor reliability. Our modular approach differentiates us from the competition by affording a shorter conversion time and the ability to use newer electric vehicle components that haven\u27t been used in the past. This process can be applied to pre-smog vehicles and other classics so they can be enjoyed by their owners on the road again, just as they were meant to be
Radiative Contributions to the Effective Action of Self-Interacting Scalar Field on a Manifold with Boundary
The effect of quantum corrections to a conformally invariant field theory for
a self-interacting scalar field on a curved manifold with boundary is
considered. The analysis is most easily performed in a space of constant
curvature the boundary of which is characterised by constant extrinsic
curvature. An extension of the spherical formulation in the presence of a
boundary is attained through use of the method of images. Contrary to the
consolidated vanishing effect in maximally symmetric space-times the
contribution of the massless "tadpole" diagram no longer vanishes in
dimensional regularisation. As a result, conformal invariance is broken due to
boundary-related vacuum contributions. The evaluation of one-loop contributions
to the two-point function suggests an extension, in the presence of matter
couplings, of the simultaneous volume and boundary renormalisation in the
effective action.Comment: 14 pages, 1 figure. Additional references and minor elucidating
remarks added. To appear in Classical and Quantum Gravit
Spherical Formulation for Diagramatic Evaluations on a Manifold with Boundary
The mathematical formalism necessary for the diagramatic evaluation of
quantum corrections to a conformally invariant field theory for a
self-interacting scalar field on a curved manifold with boundary is considered.
The evaluation of quantum corrections to the effective action past one-loop
necessitates diagramatic techniques. Diagramatic evaluations and higher
loop-order renormalisation can be best accomplished on a Riemannian manifold of
constant curvature accommodating a boundary of constant extrinsic curvature. In
such a context the stated evaluations can be accomplished through a consistent
interpretation of the Feynman rules within the spherical formulation of the
theory for which the method of images allows. To this effect, the mathematical
consequences of such an interpretation are analyzed and the spherical
formulation of the Feynman rules on the bounded manifold is, as a result,
developed.Comment: 12 pages, references added. To appear in Classical and Quantum
Gravit
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