1,243 research outputs found

    β-decay half-lives and β-delayed neutron emission probabilities for several isotopes of Au, Hg, Tl, Pb, and Bi, beyond N = 126

    Get PDF
    Background: There have been measurements on roughly 230 nuclei that are β-delayed neutron emitters. They range from 8 He up to 150La. Apart from 210Tl, with a branching ratio of only 0.007%, no other neutron emitter has been measured beyond A = 150. Therefore, new data are needed, particularly in the region of heavy nuclei around N = 126, in order to guide theoretical models and help understand the formation of the third r-process peak at A ∼ 195. Purpose: To measure both β-decay half-lives and neutron branching ratios of several neutron-rich Au, Hg, Tl, Pb, and Bi isotopes beyond N = 126. Method: Ions of interest were produced by fragmentation of a 238U beam, selected and identified via the GSI-FRS fragment separator. A stack of segmented silicon detectors (SIMBA) was used to measure ion implants and β decays. An array of 30 3 He tubes embedded in a polyethylene matrix (BELEN) was used to detect neutrons with high efficiency and selectivity. A self-triggered digital system is employed to acquire data and to enable time correlations. The latter were analyzed with an analytical model and results for the half-lives and neutron-branching ratios were derived by using the binned maximum-likelihood method. Results: Twenty new β-decay half-lives are reported for 204−206Au, 208–211Hg, 211–216Tl, 215–218Pb, and 218–220Bi, nine of them for the first time. Neutron emission probabilities are reported for 210,211Hg and 211–216Tl. Conclusions: The new β-decay half-lives are in good agreement with previous measurements on nuclei in this region. The measured neutron emission probabilities are comparable to or smaller than values predicted by global models such as relativistic Hartree Bogoliubov plus the relativistic quasi-particle random phase approximation (RHB + RQRPA).Spanish Ministerio de Economía y Competitividad-FPA2011- 28770-C03-03, FPA2008-04972-C03-3, AIC-D2011-0705, FPA2011-24553, FPA2008-6419, FPA2010-17142, FPA2014-52823-C2-1-P, FPA2014- 52823-C2-2-P, and CPAN CSD-2007-00042 (Ingenio2010)Program Severo Ochoa-SEV-2014-0398German Helmholtz Association (Young Investigators)-VH-NG 627 (LISA-Lifetime Spectroscopy for Astrophysics)Nuclear Astrophysics Virtual Institute-VH-VI-417German Bundesministerium für Bildung und Forschung-06MT7178 / 05P12WOFNFSpanish Nuclear Security Council (CSN)-Catedra ArgosUK Science & Technology Facilities Council (STFC)-ST/F012012/

    Cyber Physical Energy Systems Modules for Power Sharing Controllers in Inverter Based Microgrids

    Get PDF
    The Microgrids (MGs) are an effective way to deal with the smart grid challenges, including service continuity in the event of a grid interruption, and renewable energy integration. The MGs are compounded by multiple distributed generators (DGs), and the main control goals are load demand sharing and voltage and frequency stability. Important research has been reported to cope with the implementation challenges of the MGs including the power sharing control problem, where the use of cybernetic components such as virtual components, and communication systems is a common characteristic. The use of these cybernetic components to control complex physical systems generates new modeling challenges in order to achieve an adequate balance between complexity and accuracy in the MG model. The standardization problem of the cyber-physical MG models is addressed in this work, using a cyber-physical energy systems (CPES) modeling methodology to build integrated modules, and define the communication architectures that each power sharing control strategy requires in an AC-MG. Based on these modules, the control designer can identify the signals and components that eventually require a time delay analysis, communication requirements evaluation, and cyber-attacks’ prevention strategies. Similarly, the modules of each strategy allow for analyzing the potential advantages and drawbacks of each power sharing control technique from a cyber physical perspective

    La proteína de estrés, heat shock cognate (hsc70) se sobreexpresa en osteoblastos sometidos a centrifugación

    Get PDF
    Antecedentes. El osteoblasto tiene la capacidadde estimular la neoformación del tejido óseo,mediante la síntesis de proteínas tales como lasproteínas morfogenéticas, factores de crecimientoy proteínas colágenas y no colágenas. A suvez, indirectamente controla los procesos dereabsorción sintetizando otra serie de proteínasestimuladoras de la actividad osteoclastogénica.Objetivo. El propósito de este trabajo de investigaciónfue analizar la expresión de la proteínade choque térmico HSC70 en un cultivo primariode osteoblastos, después de someterlo a una fuerzatensil mediante centrifugación, determinandoel patrón de proteínas mediante análisiselectroforético.Material y métodos. A partir de cráneos deratones lactantes ICR se obtuvieron cultivos decélulas con características morfológicas tipofibroblastoide, con prolongaciones alargadas ycitoplasmas ligeramente cuboidales que sugiereun cultivo enriquecido de osteoblastos; loscuales fueron sometidos a centrifugación y seanalizó por inmunocitoquímica, electroforesis yWestern blot la expresión diferencial de la proteínaHSC70.Resultados. La técnica de electroforesis SDSPAGEunidimensional no permitió determinardiferencias en el patrón de corrido entreosteoblastos tratados respecto a los no tratadoscon la fuerza tensil. Sin embargo, la proteínaHSC70 se sobre-expresa en osteoblastos sometidosa centrifugación analizada mediante la técnica de Western blot e inmunohistoquímica.Conclusión. Aunque la electroforesis no determinódiferencias en el patrón de corrido,la proteína de estrés HSC70 se sobre-expresóen osteoblastos sometidos a centrifugaciónanalizada mediante la técnica de Western blote inmunocitoquímica, sugiriendo que es importanteen este tipo de estrés

    Measurement of the 70Ge(n,γ) cross section up to 300 keV at the CERN n_TOF facility

    Get PDF
    Neutron capture data on intermediate mass nuclei are of key importance to nucleosynthesis in the weak component of the slow neutron capture processes, which occurs in massive stars. The (n,γ) cross section on 70Ge, which is mainly produced in the s process, was measured at the neutron time-of-flight facility n_TOF at CERN. Resonance capture kernels were determined up to 40 keV neutron energy and average cross sections up to 300 keV. Stellar cross sections were calculated from kT =5 keV tokT =100 keV and are in very good agreement with a previous measurement by Walter and Beer (1985) and recent evaluations. Average cross sectionsareinagreementwithWalterandBeer(1985)overmostoftheneutronenergyrangecovered,whilethey aresystematicallysmallerforneutronenergiesabove150keV.Wehavecalculatedisotopicabundancesproduced in s-process environments in a 25 solar mass star for two initial metallicities (below solar and close to solar). While the low metallicity model reproduces best the solar system germanium isotopic abundances, the close to solar model shows a good global match to solar system abundances in the range of mass numbers A=60–80.Austrian Science Fund J3503Adolf Messer Foundation ST/M006085/1European Research Council ERC2015-StGCroatian Science Foundation IP-2018-01-857

    High plasma levels of soluble ST2 but not its ligand IL-33 is associated with severe forms of pediatric dengue

    Get PDF
    Q2Q1766-771Identification of early determinants of dengue disease progression, which could potentially enable individualized patient care are needed at present times. Soluble ST2 (sST2) has been recently reported to be elevated in the serum of children older than 2 years old and adults with dengue infection and it was correlated with secondary infections as well as with severe presentations of the disease. The mechanism by which secreted ST2 is linked to severe dengue and plasma leakage remains unclear. One possibility is that IL-33 ligand may be elevated, contributing to membrane bound ST2 as part of the immune activation in dengue infection. We determined plasma levels of sST2 and the ligand IL-33 in 66 children with acute secondary dengue infections clinically classified using the guidelines of the World Health Organization, 2009. Dengue infection showed significant increases in cytokines IL-12p70, IL-10, IL-8, IL-6, IL-1β and TNFα measured by flow cytometry based assay compared to uninfected individuals. In contrast, IL-33 levels remained unchanged between infected and uninfected individuals. The levels of sST2 positively correlated with values of IL-6 and IL-8 and inversely correlated with number of median value of platelet levels. In addition to circulating cytokine positive correlations we found that sST2 and isoenzyme creatine kinase-MB (CK-MB), a marker of myocardial muscle damage present in severe dengue cases were associated. Our pediatric study concluded that in dengue infections sST2 elevation does not involve concomitant changes of IL-33 ligand. We propose a study to assess its value as a predictor factor of disease severity

    Pulse processing routines for neutron time-of-flight data

    Get PDF
    A pulse shape analysis framework is described, which was developed for n_TOF-Phase3, the third phase in the operation of the n_TOF facility at CERN. The most notable feature of this new framework is the adoption of generic pulse shape analysis routines, characterized by a minimal number of explicit assumptions about the nature of pulses. The aim of these routines is to be applicable to a wide variety of detectors, thus facilitating the introduction of the new detectors or types of detectors into the analysis framework. The operational details of the routines are suited to the specific requirements of particular detectors by adjusting the set of external input parameters. Pulse recognition, baseline calculation and the pulse shape fitting procedure are described. Special emphasis is put on their computational efficiency, since the most basic implementations of these conceptually simple methods are often computationally inefficient.Croatian Science Foundation - Project No. 168

    First tests of the applicability of γ-ray imaging for background discrimination in time-of-flight neutron capture measurements

    Get PDF
    In this work we explore for the first time the applicability of using γ-ray imaging in neutron capture measurements to identify and suppress spatially localized background. For this aim, a pinhole gamma camera is assembled, tested and characterized in terms of energy and spatial performance. It consists of a monolithic CeBr3 scintillating crystal coupled to a position-sensitive photomultiplier and readout through an integrated circuit AMIC2GR. The pinhole collimator is a massive carven block of lead. A series of dedicated measurements with calibrated sources and with a neutron beam incident on a 197Au sample have been carried out at n_TOF, achieving an enhancement of a factor of two in the signal-to-background ratio when selecting only those events coming from the direction of the sample.España, Ministerio de Economía y Competitivdad FPA2011-24553España, Ministerio de Economía y Competitivdad FPA2013-45083-PEspaña, Ministerio de Economía y Competitivdad SEV-2014-039

    P1917 Antiretrovirals adverse reactions from a prospective HIV AIDS cohort study in Bogotá, Colombia

    Get PDF
    Comunicación breves550Background: Adverse Drug Reactions (ADR), lead not just to a high percentage of therapy abandonment, but also to a poor adherence to treatment instructions resulting in failure of therapy. The purpose of this study was to show the relation between the use of drugs and ADRs, their impact on treatment and the severity of reaction as defined by the DAIDS scale
    corecore