Phi meson production in near threshold proton-nucleus collisions

The cross section for production of Phi mesons in proton-nucleus reactions is calculated as a function of the target mass. The decay width of the Phi meson is affected by the change of the masses of the Phi, K+ and K- mesons in the medium. A strong attractive K- potential leads to a measurable change of the behavior of the cross section as a function of of the target mass. Comparison between the kaon and electron decay modes are made.Comment: 4 pages, 1figure, new figure, new reference

An investigation of the degradation of Fluorinated Ethylene Propylene (FEP) copolymer thermal blanketing materials aboard LDEF in the laboratory

Samples of fluorinated ethylene propylene copolymer thermal blanketing material, recovered from the Long Duration Exposure Facility (LDEF), were investigated to determine the nature and the extent of degradation due to exposure to the low-Earth-orbit environment. Samples recovered from the ram-facing direction of LDEF, which received vacuum-ultraviolet (VUV) radiation and atomic-oxygen impingement, and samples from the trailing edge, which received almost exclusively VUV exposure, were investigated by scanning electron microscopy and atomic force microscopy. The most significant result of this investigation was found on samples that received only VUV exposure. These samples possessed a hard, embrittled surface layer that was absent from the atomic-oxygen exposed sample and from unexposed control samples. This surface layer is believed to be responsible for the 'synergistic' effect between VUV and atomic oxygen. Overall, the investigation revealed dramatically different morphologies for the two samples. The sample receiving both atomic-oxygen and VUV exposure was deeply eroded and had a characteristic 'rolling' surface morphology, while the sample that received only VUV exposure showed mild erosion and a surface morphology characterized by sharp high-frequency peaks. The morphologies observed in the LDEF samples, including the embrittled surface layer, were successfully duplicated in the laboratory

Heavy Quark Diffusion and Lattice Correlators

We study charmonia correlators at finite temperature. We analyze to what extent heavy quarkonia correlators are sensitive to the effect of heavy quark transport and whether it is possible to constrain the heavy quark diffusion constant by lattice calculations. Preliminary lattice calculations of quarkonia correlators performed on anisotropic lattices show that they are sensitive to the effect of heavy quark transport, but much detailed calculations are required to constrain the value of the heavy quark diffusion constant.Comment: Based on talks presented on Lattice 2005, Extreme QCD 2005 and Quark Matter 2005, 5 pages, 4 Figure

Decoupling Simulated Annealing From Massive Multiplayer Online Role-Playing Games in RAID

End-users agree that compact technology are an interesting new topic in the field of electri- cal engineering, and physicists concur. In fact, few futurists would disagree with the deploy- ment of Byzantine fault tolerance, demonstrates the structured importance of cryptography. We construct a novel algorithm for the simulation of write-ahead logging (JDL), validating that Byzantine fault tolerance can be made peer-to- peer, classical, and stable. It is often an important mission but is supported by previous work in the field

"Killing them softly" … challenges in the Bacillus subtilis spore inactivation by plasma sterilization

The elimination of bacterial endospores is absolutely essential in numerous fields, ranging from hospital hygiene, the food processing industry, all the way to the space industry. A major goal of space exploration is the search for signatures of life forms and biomolecules on other planetary bodies and moons in our solar system. The transfer of microorganisms or biomolecules of terrestrial origin to critical areas of exploration is of particular risk to impact the development and integrity of life-detection missions.1 Plasma sterilization is a promising alternative to conventional sterilization methods for spaceflight purposes. Due to their extraordinary resistance properties, spores of the Gram-positive bacterium Bacillus subtilis are used as biological indicators for decontamination studies to identify the relevant mechanism that leads to the rapid bacterial inactivation.1,3 Here, we present novel insights into the key factors involved in spore inactivation by low pressure plasma sterilization using a double inductively-coupled plasma reactor. (2,4) In order to standardize the assessment of inactivation efficiencies by plasma discharges, an electrically driven spray deposition device was developed, allowing fast, reproducible, and homogeneous preparation of B. subtilis spore monolayers. We demonstrate that plasma discharges caused significant physical damage to spore surface structures as visualized by atomic force microscopy. A systematic analysis of B. subtilis spores lacking individual coat and crust layers - the first barrier to environmental influences – revealed the coat to be one of the contributing factors in the spore resistance to plasma sterilization. (2-4) Furthermore, we identified spore-specific and general protection mechanisms and DNA repair pathways during spore germination and outgrowth after plasma treatment, leading to a better understanding of the complex molecular mechanisms involved in the inactivation by plasma sterilization processes

Nuclear suppression of heavy quark production at forward rapidities in relativistic heavy ion collisions

We calculate nuclear suppression $R_{AA}$ of heavy quarks produced from the initial fusion of partons in nucleus-nucleus collisions at RHIC and LHC energies. We take the shadowing as well as the energy loss suffered by them while passing through Quark Gluon Plasma into account. We obtain results for charm and bottom quarks at several rapidities using different mechanisms for energy loss, to see if we can distinguish between them.Comment: 21 pages including 13 figures. To appear in J. Phys.

Spatiotemporal Response of Crystals in X-ray Bragg Diffraction

The spatiotemporal response of crystals in x-ray Bragg diffraction resulting from excitation by an ultra-short, laterally confined x-ray pulse is studied theoretically. The theory presents an extension of the analysis in symmetric reflection geometry [1] to the generic case, which includes Bragg diffraction both in reflection (Bragg) and transmission (Laue) asymmetric scattering geometries. The spatiotemporal response is presented as a product of a crystal-intrinsic plane wave spatiotemporal response function and an envelope function defined by the crystal-independent transverse profile of the incident beam and the scattering geometry. The diffracted wavefields exhibit amplitude modulation perpendicular to the propagation direction due to both angular dispersion and the dispersion due to Bragg's law. The characteristic measure of the spatiotemporal response is expressed in terms of a few parameters: the extinction length, crystal thickness, Bragg angle, asymmetry angle, and the speed of light. Applications to self-seeding of hard x-ray free electron lasers are discussed, with particular emphasis on the relative advantages of using either the Bragg or Laue scattering geometries. Intensity front inclination in asymmetric diffraction can be used to make snapshots of ultra-fast processes with femtosecond resolution

Pressure as a Source of Gravity

The active mass density in Einstein's theory of gravitation in the analog of Poisson's equation in a local inertial system is proportional to $\rho+3p/c^2$. Here $\rho$ is the density of energy and $p$ its pressure for a perfect fluid. By using exact solutions of Einstein's field equations in the static case we study whether the pressure term contributes towards the mass

Estrogen inhibits GH signaling by suppressing GH-induced JAK2 phosphorylation, an effect mediated by SOCS-2

Oral estrogen administration attenuates the metabolic action of growth hormone (GH) in humans. To investigate the mechanism involved, we studied the effects of estrogen on GH signaling through Janus kinase (JAK)2 and the signal transducers and activators of transcription (STATs) in HEK293 cells stably expressing the GH receptor (293GHR), HuH7 (hepatoma) and T-47D (breast cancer) cells. 293GHR cells were transiently transfected with an estrogen receptor-α expression plasmid and luciferase reporters with binding elements for STAT3 and STAT5 or the β-casein promoter. GH stimulated the reporter activities by four- to sixfold. Cotreatment with 17β-estradiol (E2) resulted in a dose-dependent reduction in the response of all three reporters to GH to a maximum of 49-66% of control at 100 nM (P < 0.05). No reduction was seen when E2 was added 1-2 h after GH treatment. Similar inhibitory effects were observed in HuH7 and T-47D cells. E2 suppressed GH-induced JAK2 phosphorylation, an effect attenuated by actinomycin D, suggesting a requirement for gene expression. Next, we investigated the role of the suppressors of cytokine signaling (SOCS) in E2 inhibition. E2 increased the mRNA abundance of SOCS-2 but not SOCS-1 and SOCS-3 in HEK293 cells. The inhibitory effect of E2 was absent in cells lacking SOCS-2 but not in those lacking SOCS-1 and SOCS-3. In conclusion, estrogen inhibits GH signaling, an action mediated by SOCS-2. This paper provides evidence for regulatory interaction between a sex steroid and the GH/JAK/STAT pathway, in which SOCS-2 plays a central mechanistic role