6,184 research outputs found

    Line Emission in the Brightest Cluster Galaxies of the NOAO Fundamental Plane and Sloan Digital Sky Surveys

    Full text link
    We examine the optical emission line properties of Brightest Cluster Galaxies (BCGs) selected from two large, homogeneous datasets. The first is the X-ray selected National Optical Astronomy Observatory Fundamental Plane Survey (NFPS), and the second is the C4 catalogue of optically selected clusters built from the Sloan Digital Sky Survey Data Release ~3 (SDSS DR3). Our goal is to better understand the optical line emission in BCGs with respect to properties of the galaxy and the host cluster. Throughout the analysis we compare the line emission of the BCGs to that of a control sample made of the other bright galaxies near the cluster centre. Overall, both the NFPS and SDSS show a modest fraction of BCGs with emission lines (~15%). No trend in the fraction of emitting BCGs as a function of galaxy mass or cluster velocity dispersion is found. However we find that, for those BCGs found in cooling flow clusters, 71^{+9}_{-14}% have optical emission. Furthermore, if we consider only BCGs within 50kpc of the X-ray centre of a cooling flow cluster, the emission-line fraction rises further to 100^{+0}_{-15}%. Excluding the cooling flow clusters, only ~10% of BCGs are line emitting, comparable to the control sample of galaxies. We show that the physical origin of the emission line activity varies: in some cases it has LINER-like line ratios, whereas in others it is a composite of star-formation and LINER-like activity. We conclude that the presence of emission lines in BCGs is directly related to the cooling of X-ray gas at the cluster centre.Comment: Accepted for publication in MNRAS. 13 pages mn2e style with 7 figures and 2 table

    Employment Arbitration Agreements: The Case for Ethical Standards for Dispute Resolution System Designers

    Get PDF
    Dispute resolution design is an emerging field, both academically and professionally. Attorneys, mediators, and arbitrators, the other roles in the alternative dispute resolution process, have codes of ethics which guide their conduct. Dispute resolution designers, however, have no such guidelines. This article uses the example of mandatory arbitration agreements in the employment context to illustrate why this lack of ethical guidelines for dispute resolutions designers is problematic. In recent years, mandatory arbitration agreements significantly impacted employment law and litigation. The two most problematic provisions that often appear in mandatory arbitration agreements in the workplace context are cost sharing provisions and class action (or multi-party) waivers. Courts have been hostile to efforts to minimalize the impact of class action waivers in arbitration agreements, and arbitration services have been powerless to ease their impact in light of the developing jurisprudence. This paper will examine this issue and explore how the enforceability of mandatory arbitration in employment cases has evolved through the courts. The paper will also discuss a possible path to overcoming the negative impact of these agreements and propose a modification in the approach of dispute resolution designers that would provide a possible remedy

    Regional differences in store-operated Ca2+ entry in the epithelium of the intact human lens

    Get PDF
    An elevated level of Ca2+ is an important factor in cataract, yet precisely how Ca2+ enters the lens is unknown. Lens epithelial cells contain a range of G-protein–coupled receptors and receptor tyrosine kinases that induce increases in intracellular Ca2+. Receptor-associated Ca2+ influx is, therefore, likely to be an important route for Ca2+ influx to the lens. The authors investigated stimulated and passive Ca2+ influx in in situ human lens epithelium. Ca2+ changes in equatorial (E) and central anterior (CA) epithelial cells were monitored with the use of a Ca2+ indicator (Fluo4) and confocal microscopy. Gene expression was monitored by RT-PCR and immunoblotting. Adenosine triphosphate (ATP) induced Ca2+ responses that were smaller in CA than E. Ca2+ store depletion, using ATP (100 µM) or thapsigargin (1 µM), revealed greater relative store capacity and Ca2+ influx in E. Ca2+ influx was blocked by La3+ (0.5 µM) in both regions. Unstimulated Ca2+ influx was greater in E than CA. Greater expression of Orai1 and STIM1 was detected in E than in CA. Greater Ca2+ store capacity and Ca2+ influx in E compared with CA reflects underlying differences in proliferation and differentiation between the regions. The relatively small resting Ca2+ influx in CA epithelium suggests that store-operated Ca2+ entry (SOCE) is the main route of Ca2+ influx in these cells. Greater resting influx and SOCE in E cells suggests that these are a major route for Ca2+ influx into the lens. Increased expression of Orai1 and STIM1 in E could account for the differences in Ca2+ entry. Receptor activation will modulate Ca2+ influx, and inappropriate activity may contribute to cortical cataract

    Multidisciplinary management of type 2 diabetes in children and adolescents

    Get PDF
    Although once considered a disease of adults, the prevalence of type 2 diabetes in youth is increasing at a significant rate. Similar to adults, youth with type 2 diabetes are at increased risk for developing hypertension, lipid abnormalities, renal disease, and other diabetes-related complications. However, children and adolescents with type 2 diabetes also face many unique management challenges that are different from adults with type 2 diabetes or children with type 1 diabetes. To deliver safe, effective, high-quality, cost-effective health care to adolescents with type 2 diabetes, reorganization and redesign of health care systems are needed. Multidisciplinary health care teams, which allow individuals with specialized training to maximally utilize their skills within an organized diabetes treatment team, may increase efficiency and effectiveness and may improve outcomes in children with type 2 diabetes. This review article provides a brief review of type 2 diabetes in children and adolescents, provides an overview of multidisciplinary health care teams, and discusses the role of multidisciplinary health care management in youth with type 2 diabetes

    Are Recent Peculiar Velocity Surveys Consistent?

    Get PDF
    We compare the bulk flow of the SMAC sample to the predictions of popular cosmological models and to other recent large-scale peculiar velocity surveys. Both analyses account for aliasing of small-scale power due to the sparse and non-uniform sampling of the surveys. We conclude that the SMAC bulk flow is in marginal conflict with flat COBE-normalized Lambda-CDM models which fit the cluster abundance constraint. However, power spectra which are steeper shortward of the peak are consistent with all of the above constraints. When recent large-scale peculiar velocity surveys are compared, we conclude that all measured bulk flows (with the possible exception of that of Lauer & Postman) are consistent with each other given the errors, provided the latter allow for `cosmic covariance'. A rough estimate of the mean bulk flow of all surveys (except Lauer & Postman) is ~400 km/s towards l=270, b=0.Comment: 8 pages, 3 figures. To appear in Proceedings of the Cosmic Flows Workshop, Victoria, B. C., Canada, July 1999, eds. S. Courteau, M. Strauss, and J. Willic

    Characterization of a Double Mesospheric Bore Over Europe

    Get PDF
    Observations of a pair of mesospheric bore disturbances that propagated through the nighttime mesosphere over Europe are presented. The observations were made at the Padua Observatory, Asiago (45.9\ub0N, 11.5\ub0E), by the Boston University all-sky imager on 11 March 2013. The bores appeared over the northwest horizon, approximately 30 min apart, and propagated toward the southeast. Using additional satellite and radar data, we present evidence indicating the bores originated in the mesosphere from a single, larger-scale mesospheric disturbance propagating through the mesopause region. Furthermore, the large-scale mesospheric disturbance appeared to be associated with an intense weather disturbance that moved southeastward over the United Kingdom and western Europe during 10 and 11 March
    • …
    corecore