343 research outputs found

    General Relativistic Effects in the Core Collapse Supernova Mechanism

    Get PDF
    We apply our recently developed code for spherically symmetric, fully general relativistic (GR) Lagrangian hydrodynamics and multigroup flux-limited diffusion neutrino transport to examine the effects of GR on the hydrodynamics and transport during collapse, bounce, and the critical shock reheating phase of core collapse supernovae. Comparisons of models computed with GR versus Newtonian hydrodynamics show that collapse to bounce takes slightly less time in the GR limit, and that the shock propagates slightly farther out in radius before receding. After a secondary quasistatic rise in the shock radius, the shock radius declines considerably more rapidly in the GR simulations than in the corresponding Newtonian simulations. During the shock reheating phase, core collapse computed with GR hydrodynamics results in a substantially more compact structure from the center out to the stagnated shock. The inflow speed of material behind the shock is also increased. Comparisons also show that the luminosity and rms energy of any neutrino flavor during the shock reheating phase increases when switching from Newtonian to GR hydrodynamics, and decreases when switching from Newtonian to GR transport. This latter decrease in neutrino luminosities and rms energies is less in magnitude than the increase that arise when switching from Newtonian to GR hydrodynamics, with the result that a fully GR simulation gives higher neutrino luminosities and harder neutrino spectra than a fully Newtonian simulation of the same precollapse model.Comment: 35 pages, 23 figure

    Decay rate and renormalized frequency shift of a quantum wire Wannier exciton in a planar microcavity

    Full text link
    The superradiant decay rate and frequency shift of a Wannier exciton in a one-dimensional quantum wire are studied. It is shown that the dark mode exciton can be examined experimentally when the quantum wire is embedded in a planar microcavity. It is also found that the decay rate is greatly enhanced as the cavity length LcL_{c} is equal to the multiple wavelength of the emitted photon. Similar to its decay rate counterpart, the frequency shift also shows discontinuities at resonant modes.Comment: 12 pages, 2 figures. To appear in P. R. B. September 200

    State Variation in Squamous Cell Carcinoma of the anus incidence and Mortality, and association With Hiv/Aids and Smoking in the United States

    Get PDF
    PURPOSE: Squamous cell carcinoma of the anus (SCCA) incidence and mortality rates are rising in the United States. Understanding state-level incidence and mortality patterns and associations with smoking and AIDS prevalence (key risk factors) could help unravel disparities and provide etiologic clues. METHODS: Using the US Cancer Statistics and the National Center for Health Statistics data sets, we estimated state-level SCCA incidence and mortality rates. Rate ratios (RRs) were calculated to compare incidence and mortality in 2014-2018 versus 2001-2005. The correlations between SCCA incidence with current smoking (from the Behavioral Risk Factor Surveillance System) and AIDS (from the HIV Surveillance system) prevalence were evaluated using Spearman\u27s rank correlation coefficient. RESULTS: Nationally, SCCA incidence and mortality rates (per 100,000) increased among men (incidence, 2.29-3.36, mortality, 0.46-0.74) and women (incidence, 3.88-6.30, mortality, 0.65-1.02) age ≥ 50 years, but decreased among men age \u3c 50 years and were stable among similar-aged women. In state-level analysis, a marked increase in incidence (≥ 1.5-fold for men and ≥ two-fold for women) and mortality (≥ two-fold) for persons age ≥ 50 years was largely concentrated in the Midwestern and Southeastern states. State-level SCCA incidence rates in recent years (2014-2018) among men were correlated ( CONCLUSION: During 2001-2005 to 2014-2018, SCCA incidence and mortality nearly doubled among men and women age ≥ 50 years living in Midwest and Southeast. State variation in AIDS and smoking patterns may explain variation in SCCA incidence. Improved and targeted prevention is needed to combat the rise in SCCA incidence and mitigate magnifying geographic disparities

    Triclocarban Mediates Induction of Xenobiotic Metabolism through Activation of the Constitutive Androstane Receptor and the Estrogen Receptor Alpha

    Get PDF
    Triclocarban (3,4,4′-trichlorocarbanilide, TCC) is used as a broad-based antimicrobial agent that is commonly added to personal hygiene products. Because of its extensive use in the health care industry and resistance to degradation in sewage treatment processes, TCC has become a significant waste product that is found in numerous environmental compartments where humans and wildlife can be exposed. While TCC has been linked to a range of health and environmental effects, few studies have been conducted linking exposure to TCC and induction of xenobiotic metabolism through regulation by environmental sensors such as the nuclear xenobiotic receptors (XenoRs). To identify the ability of TCC to activate xenobiotic sensors, we monitored XenoR activities in response to TCC treatment using luciferase-based reporter assays. Among the XenoRs in the reporter screening assay, TCC promotes both constitutive androstane receptor (CAR) and estrogen receptor alpha (ERα) activities. TCC treatment to hUGT1 mice resulted in induction of the UGT1A genes in liver. This induction was dependent upon the constitutive active/androstane receptor (CAR) because no induction occurred in hUGT1Car−/− mice. Induction of the UGT1A genes by TCC corresponded with induction of Cyp2b10, another CAR target gene. TCC was demonstrated to be a phenobarbital-like activator of CAR in receptor-based assays. While it has been suggested that TCC be classified as an endocrine disruptor, it activates ERα leading to induction of Cyp1b1 in female ovaries as well as in promoter activity. Activation of ERα by TCC in receptor-based assays also promotes induction of human CYP2B6. These observations demonstrate that TCC activates nuclear xenobiotic receptors CAR and ERα both in vivo and in vitro and might have the potential to alter normal physiological homeostasis. Activation of these xenobiotic-sensing receptors amplifies gene expression profiles that might represent a mechanistic base for potential human health effects from exposure to TCC

    Nodavirus colonizes and replicates in the testis of gilthead seabream and European sea bass modulating its immune and reproductive functions

    Get PDF
    Viruses are threatening pathogens for fish aquaculture. Some of them are transmitted through gonad fluids or gametes as occurs with nervous necrosis virus (NNV). In order to be transmitted through the gonad, the virus should colonize and replicate inside some cell types of this tissue and avoid the subsequent immune response locally. However, whether NNV colonizes the gonad, the cell types that are infected, and how the immune response in the gonad is regulated has never been studied. We have demonstrated for the first time the presence and localization of NNV into the testis after an experimental infection in the European sea bass (Dicentrarchus labrax), and in the gilthead seabream (Sparus aurata), a very susceptible and an asymptomatic host fish species, respectively. Thus, we localized in the testis viral RNA in both species using in situ PCR and viral proteins in gilthead seabream by immunohistochemistry, suggesting that males might also transmit the virus. In addition, we were able to isolate infective particles from the testis of both species demonstrating that NNV colonizes and replicates into the testis of both species. Blood contamination of the tissues sampled was discarded by completely fish bleeding, furthermore the in situ PCR and immunocytochemistry techniques never showed staining in blood vessels or cells. Moreover, we also determined how the immune and reproductive functions are affected comparing the effects in the testis with those found in the brain, the main target tissue of the virus. Interestingly, NNV triggered the immune response in the European sea bass but not in the gilthead seabream testis. Regarding reproductive functions, NNV infection alters 17β-estradiol and 11-ketotestosterone production and the potential sensitivity of brain and testis to these hormones, whereas there is no disruption of testicular functions according to several reproductive parameters. Moreover, we have also studied the NNV infection of the testis in vitro to assess local responses. Our in vitro results show that the changes observed on the expression of immune and reproductive genes in the testis of both species are different to those observed upon in vivo infections in most of the casesMINECO and FEDER (AGL2010-20801-C02-01; AGL2010-20801-C02-02; AGL2013-43588-P); Fundación Séneca (04538/GERM/06)Versión del editor4,411

    Electromagnetic Wave Theory and Applications

    Get PDF
    Contains table of contents for Section 3, research summary and reports on six research projects.Joint Services Electronics Program (Contract DAAL 03-86-K-0002)Joint Services Electronics Program (Contract DAAL 03-89-C-0001)U.S. Navy - Office of Naval Research (Contract N00014-86-K-0533)National Science Foundation (Contract ECS 86-20029)U.S. Army Research Office (Contract DAAL03 88-K-0057)International Business Machine CorporationSchlumberger-Doll ResearchNational Aeronautics and Space Administration (Contract NAG 5-270)U.S. Navy - Office of Naval Research (Contract N00014-83-K-0258)National Aeronautics and Space Administration (Contract NAG 5-769)U.S. Army Corps of Engineers - Waterways Experimental Station (Contract DACA39-87-K-0022)Simulation TechnologiesU.S. Air Force - Rome Air Development Center (Contract F19628-88-K-0013)U.S. Navy - Office of Naval Research (Contract N00014-89-J-1107)Digital Equipment Corporatio
    corecore