Wind Signatures In The X-Ray Emission-Line Profiles Of The Late-O Supergiant Zeta Orionis

X-ray line-profile analysis has proved to be the most direct diagnostic of the kinematics and spatial distribution of the very hot plasma around O stars. The Doppler-broadened line profiles provide information about the velocity distribution of the hot plasma, while the wavelength-dependent attenuation across a line profile provides information about the absorption to the hot plasma, thus providing a strong constraint on its physical location. In this paper, we apply several analysis techniques to the emission lines in the Chandra High Energy Transmission Grating Spectrometer (HETGS) spectrum of the late-O supergiant zeta Ori (O9.7 Ib), including the fitting of a simple line-profile model. We show that there is distinct evidence for blueshifts and profile asymmetry, as well as broadening in the X-ray emission lines of zeta Ori. These are the observational hallmarks of a wind-shock X-ray source, and the results for zeta Ori are very similar to those for the earlier O star, zeta Pup, which we have previously shown to be well fit by the same wind-shock line-profile model. The more subtle effects on the line-profile morphologies in zeta Ori, as compared to zeta Pup, are consistent with the somewhat lower density wind in this later O supergiant. In both stars, the wind optical depths required to explain the mildly asymmetric X-ray line profiles imply reductions in the effective opacity of nearly an order of magnitude, which may be explained by some combination of mass-loss rate reduction and large-scale clumping, with its associated porosity-based effects on radiation transfer. In the context of the recent reanalysis of the helium-like line intensity ratios in both zeta Ori and zeta Pup, and also in light of recent work questioning the published mass-loss rates in OB stars, these new results indicate that the X-ray emission from zeta Ori can be understood within the framework of the standard wind-shock scenario for hot stars

Measurement of the weak mixing angle with the Drell-Yan process in proton-proton collisions at the LHC

This is the Pre-Print version of the Article - Copyright @ 2011 APSA multivariate likelihood method to measure electroweak couplings with the Drell-Yan process at the LHC is presented. The process is described by the dilepton rapidity, invariant mass, and decay angle distributions. The decay angle ambiguity due to the unknown assignment of the scattered constituent quark and antiquark to the two protons in a collision is resolved statistically using correlations between the observables. The method is applied to a sample of dimuon events from proton-proton collisions at sqrt(s) = 7 TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 1.1 inverse femtobarns. From the dominant u-ubar, d-dbar to gamma*/Z to opposite sign dimuons process, the effective weak mixing angle parameter is measured to be sin^2(theta[eff]) = 0.2287 +/- 0.0020 (stat.) +/- 0.0025 (syst.). This result is consistent with measurements from other processes, as expected within the standard model

Prevalence of \u3ci\u3eRickettsia parkeri\u3c/i\u3e in \u3ci\u3eAmblyomma maculatum\u3c/i\u3e Populations of Southeastern Virginia

Amblyomma maculatum has undergone notable expansion northward from its historical region in the Gulf of Mexico, establishing populations along the East Coast into the Carolinas, Virginia, Maryland, New England, and Midwestern states. Amblyomma maculatum is an aggressive human-biting tick and the primary vector for the bacterium Rickettsia parkeri. R. parkeri is the causative agent of Rickettsia parkeri rickettsiosis in humans, a disease similar to but milder than Rocky Mountain Spotted Fever. In 1965, several A. maculatum ticks were found in Virginia, but established populations had yet to emerge. By 2010, established populations of A. maculatum were documented across Southeastern Virginia, showing higher R. parkeri prevalence (\u3e50%) compared to the historic region (R.parkeri on the expansion front raises public health concerns and questions about prevalence patterns between historic and newly established A. maculatum populations. This study analyzes Rickettsia parkeri prevalence among Amblyomma maculatum populations in Southeastern Virginia between 2018 and 2023 to determine if prevalence values remain elevated. Amblyomma maculatum DNA extracts were tested using qPCR for Rickettsia spp. DNA, then specifically for Rickettsia parkeri if the first test showed positive results. Our data will determine if prevalence values changed over time as the ticks became established in the region, which allows for potential connections between higher pathogen persistence and the beginning stages of population expansion

Training moral sensitivity through video games: A review of suitable game mechanisms

The goal of this study is to support game designers in the selection and implementation of game mechanisms to promote players’ moral sensitivity. A lack of moral sensitivity may lead people to behave unethically, without awareness for their actions’ moral implications. In this study, we conduct a theory-based evaluation of 20 distinct game mechanisms in view of their potential to promote moral sensitivity. Moral sensitivity is thereby operationalized in terms of three learning outcomes: Empathic concern for relevant groups, alertness to values/principles, and awareness for one’s vulnerability to biases. This study suggests that moral sensitivity is best promoted through a careful combination of game mechanisms, addressing all three learning outcomes