12,784 research outputs found

    An analysis of the peculiar A star HD 204411

    Get PDF
    Spectrum analysis of cool Ap star HD 20441

    High resolution observations of the L1551 bipolar outflow

    Get PDF
    The nearby dark cloud Lynds 1551 contains one of the closest examples of a well-collimated bipolar molecular outflow. This source has the largest angular size of any known outflow and was the first bipolar outflow to be detected. The outflow originates from a low-luminosity young stellar object, IRS-5. Optical and radio continuum observations show the presence of a highly collimated, ionized stellar wind orginating from close to IRS-5 and aligned with the molecular outflow. However, we have little information on the actual mechanism that generates the stellar wind and collimates it into opposed jets. The Very Large Array (VLA) observations indicate that the winds originate within 10(15) cm of IRS-5, unfortunately at a size scale difficult to resolve. For these reasons, observations of the structure and dynamics of the hypersonic molecular gas may provide valuable information on the origin and evolution of these outflows. In addition, the study of the impact of the outflowing gas on the surrounding molecular material is essential to understand the consequence these outflows have on the evolution and star formation history of the entire cloud. Moriarty-Schieven et al. (1986) obtained a oversampled map of the CO emission of a portion of both the blueshifted and redshifted outflows in LI551 using Five College Radio Astronomy Observatory 14 m telescope. The oversampled maps have been reconstructed to an effective angular resolution of 20 arcsec using a maximum entropy algorithm. A continuation of the study of Moriarty-Schieven et al. is presented. The entire L1551 outflow has now been mapped at 12 arcsec sampling requiring roughly 4000 spectra. This data has been constructed to 20 arcsec resolution to provide the first high resolution picture of the entire L1551 outflow. This new data has shown that the blueshifted lobe is more extended than previously thought and has expanded downstream sufficiently to break out of the dense molecular cloud, but the redshifted outflow is still confined within the molecular cloud. Details of the structure and kinematics of the high velocity gas are used to test the various models of the origin and evolution of outflows

    Exceptional Sentencing in Washington after \u3ci\u3eState v. Freitag\u3c/i\u3e: Pushing the Limits of the Sentencing Reform Act

    Get PDF
    In 1981 the Washington state legislature enacted the Sentencing Reform Act (SRA) with the intent of reducing disparity in sentencing through the implementation of presumptive sentencing ranges. The SRA authorizes judges to depart from the presumptive range by imposing an exceptional sentence if appropriate mitigating or aggravating factors exist. Since 1981, virtually all courts have determined a factor\u27s appropriateness by considering its relation to the factual nature of the crime itself. In State v. Freitag, however, the Washington Court of Appeals recently held that a trial court may rely on factors which do not directly relate to the nature of the crime as the basis for an exceptional sentence below the standard range. By holding that the trial court may consider a defendant\u27s personal qualities, the stated purposes of the SRA, and the defendant\u27s criminal history, the court has contradicted the intent of the legislature in passing the SRA, ignored Washington case law, and created a dangerous precedent for other courts to follow

    Analysis of F and G Subdwarfs. I. The Location of Subdwarfs in the Theoretical H-R Diagram

    Get PDF
    Spectrum scans and model stellar atmospheres have been used to locate in the (L/L_⊙, T_(eff)) plane F and G subdwarfs having known parallax A comparison is made between their position on the H-R diagram and the evolutionary tracks for Population II models of low- and high-helium content recently computed by Faulkner and Iben. The lower helium-content models are found to give somewhat more plausible ages than the high-helium models. Nevertheless, for both the low- and high-helium-content models, we find several subdwarfs with ages apparently greater than 10 X 10^9 years

    PhEMaterialism: Response-able Research & Activism

    Get PDF
    This Special Issue offers PhEmaterialisms as a way to explore the world asvital and complex, while simultaneously being response-able to the multiple ethical imperatives of late-stage capitalism. We argue that PhEmaterialist thinking and practices can help us grapple with growing educational complexities, enabling strategies toresist and create alternatives to the patterns of injustice occurring across the world, from burgeoning ethno-nationalist and neo-fascist political movements, to rising global poverty levels, to massive population displacements, to environmental degradation, to toxic internet movements grounded in misogyny, homophobia, transphobia, and xenophobia (Strom & Martin, 2017a). To understand, enquire into, and generate action worthy of the complexity of our times requires a fundamental shift in our thinking and research practice. This shift disrupts the foundational logic on which dominant thinking in education (and indeed, all Western society) is based—humanism and anthropocentrism (Braidotti, 2013; Murris, 2016; Snaza et al, 2014). Instead, we argue that we need to put theories/concepts to work in education and educational research which can better account for the multiple, entangled, ever-shifting, difference-rich nature of processes of teaching, learning, schooling, and activism. For this work, we also draw on a rich feminist legacy attentive to unequal power relations (e.g., Ahmed, 1998; Anzaldua, 1999; hooks, 1994; Spivak, 1978), and our critical approach to rethinking Vitruvian “man” is especially informed by posthuman/new materialist feminist thinkings and thinkers, including Rosi Braidotti, Donna Haraway, and Karen Barad

    Gallium(III)-Promoted Halocyclizations of 1,6-Diynes

    Get PDF
    Adrian Landreth was an REU student, summer 2014Cyclization of 1,6-diynes promoted by stoichiometric Ga(III) halides produces vinyl halides in good to excellent yields. Under acidic conditions, initially formed iodocyclization products undergo in situ Friedel-Crafts cyclizations, giving access to iodo-indenopyridines. The application of the vinyl halides in cross-coupling reactions has been explored, and mechanistic aspects of the cyclization are discussed.HIGMS CMLD Initiative (P50 GM067041) NSF REU - Adrian Landreth support (CHE 1156666) NSF - NMR purchase (CHE 0619339) NSF - HRMS purchase (CHE0443618

    An ABC transporter containing a forkhead-associated domain interacts with a serine-threonine protein kinase and is required for growth of Mycobacterium tuberculosis in mice

    Get PDF
    Forkhead-associated (FHA) domains are modular phosphopeptide recognition motifs with a striking preference for phosphothreonine-containing epitopes. FHA domains have been best characterized in eukaryotic signaling pathways but have been identified in six proteins in Mycobacterium tuberculosis, the causative organism of tuberculosis. One of these, coded by gene Rv1747, is an ABC transporter and the only one to contain two such modules. A deletion mutant of Rv1747 is attenuated in a mouse intravenous injection model of tuberculosis where the bacterial load of the mutant is 10-fold lower than that of the wild type in both lungs and spleen. In addition, growth of the mutant in mouse bone marrow-derived macrophages and dendritic cells is significantly impaired. In contrast, growth of this mutant in vitro was indistinguishable from that of the wild type. The mutant phenotype was lost when the mutation was complemented by the wild-type allele, confirming that it was due to mutation of Rv1747. Using yeast two-hybrid analysis, we have shown that the Rv1747 protein interacts with the serine-threonine protein kinase PknF. This interaction appears to be phospho-dependent since it is abrogated in a kinase-dead mutant and by mutations in the presumed activation loop of PknF and in the first FHA domain of Rv1747. These results demonstrate that the protein coded by Rv1747 is required for normal virulent infection by M. tuberculosis in mice and, since it interacts with a serine-threonine protein kinase in a kinase-dependent manner, indicate that it forms part of an important phospho-dependent signaling pathway
    corecore