BAYESIAN ANALYSIS OF TWO STELLAR POPULATIONS IN GALACTIC GLOBULAR CLUSTERS I: STATISTICAL AND COMPUTATIONAL METHODS

We develop a Bayesian model for globular clusters composed of multiple stellar populations, extending earlier statistical models for open clusters composed of simple (single) stellar populations (e.g., van Dyk et al. 2009; Stein et al. 2013). Specifically, we model globular clusters with two populations that differ in helium abundance. Our model assumes a hierarchical structuring of the parameters in which physical properties—age, metallicity, helium abundance, distance, absorption, and initial mass—are common to (i) the cluster as a whole or to (ii) individual populations within a cluster, or are unique to (iii) individual stars. An adaptive Markov chain Monte Carlo (MCMC) algorithm is devised for model fitting that greatly improves convergence relative to its precursor non-adaptive MCMC algorithm. Our model and computational tools are incorporated into an open-source software suite known as BASE-9. We use numerical studies to demonstrate that our method can recover parameters of two-population clusters, and also show model misspecification can potentially be identified. As a proof of concept, we analyze the two stellar populations of globular cluster NGC 5272 using our model and methods. (BASE-9 is available from GitHub: https://github.com/argiopetech/base/releases)

Bayesian Analysis of Two Stellar Populations in Galactic Globular Clusters II: NGC 5024, NGC 5272, and NGC 6352

We use Cycle 21 Hubble Space Telescope (HST) observations and HST archival ACS Treasury observations of Galactic Globular Clusters to find and characterize two stellar populations in NGC 5024 (M53), NGC 5272 (M3), and NGC 6352. For these three clusters, both single and double-population analyses are used to determine a best fit isochrone(s). We employ a sophisticated Bayesian analysis technique to simultaneously fit the cluster parameters (age, distance, absorption, and metallicity) that characterize each cluster. For the two-population analysis, unique population level helium values are also fit to each distinct population of the cluster and the relative proportions of the populations are determined. We find differences in helium ranging from $\sim$0.05 to 0.11 for these three clusters. Model grids with solar $\alpha$-element abundances ([$\alpha$/Fe] =0.0) and enhanced $\alpha$-elements ([$\alpha$/Fe]=0.4) are adopted.Comment: ApJ, 21 pages, 14 figures, 7 table

Transfusion-Related Acute Lung Injury

Abstract Transfusion-related acute lung injury (TRALI) is a serious complication of blood transfusion, which causes serious morbidity and is the leading cause of transfusion-associated mortality according to the FDA. The majority of TRALI cases (up to 89%) are thought to be antibody-mediated TRALI, caused by the passive infusion of white blood cell (WBC)- reactive antibodies, present in plasma-containing blood products. This thesis focuses on the role of donor WBC-reactive antibodies in TRALI, and the translation to preventive strategies

Визначення правового статусу садівницьких, городницьких та дачних товариств

Розкриваються особливості правового статусу садівницьких, городницьких та дач­них товариств, досліджується їх організаційно-правова форма та ті специфічні пра­вові ознаки, що знаходяться в її основі. У зв’язку з відсутністю правової бази діяль­ності цих товариств, робиться спроба сформувати основні теоретико-правові кон­цептуальні підходи до розуміння їх природи та змоделювати законодавчу схему регулювання їх діяльності.Раскрываются особенности правового статуса садоводческих, огороднических и дачных товариществ, исследуются их организационно-правовая форма и правовые особенности, составляющие ее основание. В связи с отсутствием правовых обоснований деятельности этих товариществ автор стремится сформировать основные теоре­тико-правовые концептуальные подходы к раскрытию их сущности и смоделировать законодательную схему регулирования деятельности рассматриваемых товариществ.In article features of legal status of garden, vegetable-garden and country companies reveal, their organizational legal form and those specific features that are in its basis are investigated. In connection with absence of legal base of activity of these communities is attempted to generate the basic theoretical-legal conceptual approaches to understanding of their nature and model legislative sphere of regulation of their activity becomes

Heat kernel estimates and spectral properties of a pseudorelativistic operator with magnetic field

Based on the Mehler heat kernel of the Schroedinger operator for a free electron in a constant magnetic field an estimate for the kernel of E_A is derived, where E_A represents the kinetic energy of a Dirac electron within the pseudorelativistic no-pair Brown-Ravenhall model. This estimate is used to provide the bottom of the essential spectrum for the two-particle Brown-Ravenhall operator, describing the motion of the electrons in a central Coulomb field and a constant magnetic field, if the central charge is restricted to Z below or equal 86