741 research outputs found

    pp-Process simulations with a modified reaction library

    Get PDF
    We have performed pp-process simulations with the most recent stellar (n,γ)(n,\gamma) cross sections from the "Karlsruhe Astrophysical Database of Nucleosynthesis in Stars" project (version v0.2, http://nuclear-astrophysics.fzk.de/kadonis). The simulations were carried out with a parametrized supernova type II shock front model (``γ\gamma process'') of a 25 solar mass star and compared to recently published results. A decrease in the normalized overproduction factor could be attributed to lower cross sections of a significant fraction of seed nuclei located in the Bi and Pb region around the NN=126 shell closure.Comment: 5 pages, 1 figure Proceedings "Nuclear Physics in Astrophysics NPA-III", Dresden/Germany (2007

    Interactions between the foreign body reaction and Staphylococcus aureus biomaterial-associated infection:Winning strategies in the derby on biomaterial implant surfaces

    Get PDF
    Biomaterial-associated infections (BAIs) are an increasing problem where antibiotic therapies are often ineffective. The design of novel strategies to prevent or combat infection requires a better understanding of how an implanted foreign body prevents the immune system from eradicating surface-colonizing pathogens. The objective of this review is to chart factors resulting in sub-optimal clearance of Staphylococcus aureus bacteria involved in BAIs. To this end, we first describe three categories of bacterial mechanisms to counter the host immune system around foreign bodies: direct interaction with host cells, modulation of intercellular communication, and evasion of the immune system. These mechanisms take place in a time frame that differentiates sterile foreign body reactions, BAIs, and soft tissue infections. In addition, we identify experimental interventions in S. aureus BAI that may impact infectious mechanisms. Most experimental treatments modulate the host response to infection or alter the course of BAI through implant surface modulation. In conclusion, the first week after implantation and infection is crucial for the establishment of an S. aureus biofilm that resists the local immune reaction and antibiotic treatment. Although established and chronic S. aureus BAI is still treatable and manageable, the focus of interventions should lie on this first period

    Pengaruh Pemanfaatan Sumber Belajar Terhadap Motivasi Belajar Siswa Kelas XI SMA Negeri 1 Batudaa Pantai Kabupaten Gorontalo

    Get PDF
    This research aims  to determine the effect of using learning resources on the  learning motivation of grade XI students of SMA  Negeri 1 Batudaa Pantai, Gorontalo regerncy. This research employs a quantitative method with an associative approach. The data used in this research is primary  data obtained from the distribution of questionners  to grade XI student of SMA Negeri 1 Batudaa Pantai. The total samples in this research are 56 respondents. The data analysis techniqueemploys simpel linear regresision. The results indicate the effect of using learning resources on students motivation at SMA  Negeri 1 Batudaa  Pantai Kabupaten Gorontalo Regerncy. The  mangnitude of the effect of using learning resources on learning motivation 63,2%, while the reamning 36,8% is influenced by  other variables not examined in this researc

    Facilitators and Barriers for Successful Implementation of Interconception Care in Preventive Child Health Care Services in the Netherlands

    Get PDF
    Objectives Successful implementation of preconception and interconception care contributes to optimizing pregnancy outcomes. While interconception care to new mothers could potentially be provided by Preventive Child Health Care services, this care is currently not routinely available in the Netherlands. The purpose of this study was to identify facilitators and barriers for implementation of interconception care in Preventive Child Health Care services. Methods We organized four focus groups in which Preventive Child Health Care physicians and nurses, related health care professionals and policymakers participated. A semi-structured interview approach was used to guide the discussion. The transcribed discussions were analyzed. Results All four groups agreed that several facilitators are present, such as the unique position to reach women and the expertise in preventive health care. Identified barriers include unfamiliarity with interconception care among patients and health care providers, as well as lack of consensus about the concept of interconception care and how it should be organized. A broad educational campaign, local adaptation, and general agreement or a guideline for standard procedures were recognized as important for future implementation. Conclusionsfor practice This study identifies potentially important facilitators and barriers for the implementation of interconception care in Preventive Child Health Care services or comparable pediatric settings. These factors should be considered and strategies developed to achieve successful implementation of interconception care

    Influence of sub-inhibitory concentrations of antimicrobials on micrococcal nuclease and biofilm formation in Staphylococcus aureus

    Get PDF
    Abstract A major contributor to biomaterial associated infection (BAI) is Staphylococcus aureus. This pathogen produces a protective biofilm, making eradication difficult. Biofilms are composed of bacteria encapsulated in a matrix of extracellular polymeric substances (EPS) comprising polysaccharides, proteins and extracellular DNA (eDNA). S. aureus also produces micrococcal nuclease (MN), an endonuclease which contributes to biofilm composition and dispersion, mainly expressed by nuc1. MN expression can be modulated by sub-minimum inhibitory concentrations of antimicrobials. We investigated the relation between the biofilm and MN expression and the impact of the application of antimicrobial pressure on this relation. Planktonic and biofilm cultures of three S. aureus strains, including a nuc1 deficient strain, were cultured under antimicrobial pressure. Results do not confirm earlier findings that MN directly influences total biomass of the biofilm but indicated that nuc1 deletion stimulates the polysaccharide production per CFU in the biofilm in in vitro biofilms. Though antimicrobial pressure of certain antibiotics resulted in significantly increased quantities of polysaccharides per CFU, this did not coincide with significantly reduced MN activity. Erythromycin and resveratrol significantly reduced MN production per CFU but did not affect total biomass or biomass/CFU. Reduction of MN production may assist in the eradication of biofilms by the host immune system in clinical situations

    Pengaruh Gaya Kepemimpinan Kepala Desa Terhadap Motivasi Kerja Aparat Desa

    Get PDF
    The purpose of this study is to  determine the influence of the Village Chief”s Leadership Style on the Work Motivation of the Village  Apparaturs in Totopo Village, Bilato Subdistruct, Gorontalo Regency. This research adopted a Quantitative approach using the associative research method. The data used were primary data obtained from distributing Questionbaires to the village apparaturs in Totopo Village, Bilato Subdistrict, Gorontalo Regerency. The Sample sizein this research was 45 respondents. The analysis technique used was simple linear regression. The research results indicated that there is influence of the village chief”s leadership style on the work motivation of village apparatus in Totopo Villag Bilato Subdistrrict, Gorontalo Regerency. The Magnitude of the influence of the Village Chief”s Leadership Style on the Work Motivation of vilage Apparatus was 62,3%, while the reaming 37,7% was influenced by variables that were not examined

    Anthropogenic lead isotopes in Antarctica

    Get PDF
    We report the first measurements of Pb isotopes in Antarctic snow, which show that even recent snow containing 2.3 pg/g is highly polluted with anthropogenic Pb. This follows from a comparison of isotope abundances of Pb in surface snow and terrestrial dust extracted from ancient Antarctic ice (Dome C, depth 308 m, approximate age 7,500 a BP), the latter being distinctly more radiogenic. This result is independent of geochemical arguments based on measurements of Al, Na and SO_4. South America is suggested as a likely source of this anthropogenic Pb. The presence of significantly less radiogenic Pb in the snow adjacent to two Antarctic base stations indicates that there is contamination from station emissions, although emission from Australia is an alternative explanation for a site 33 km from Dumont d'Urville

    HPCSA Serious Injury Narrative Test guideline

    Get PDF
    Current South African Road Accident Fund (RAF) legislation requires a medical determination of the seriousness of injuries sustained in motor vehicle accidents to determine whether the claimant is entitled to a claim for general damages. Such medical assessments are submitted in the form of RAF 4 Serious Injury Assessment Reports. Contested claims for serious injury are referred to the Health Professions Council of South Africa (HPCSA) Appeal Tribunals for final determination. The legislation prescribes 2 instruments, namely the American Medical Association (AMA) Guides (6th edition) and the Narrative Test for this purpose. Whereas the AMA Guides are published in a comprehensive book, and training courses are provided in their use, existing legislation does not provide any indication of the required structure, content or criteria of a Narrative Test report. This document is published by the HPCSA Appeal Tribunals as a guideline to the performance of the Narrative Test; what it is, reasons for applying it and who should compile it, as well as the required structure, content and criteria thereof. A Narrative Test Report should include relevant and meaningful comment in relation to each of the 6 sections described in the article.

    HST Observations of Heavy Elements in Metal-Poor Galactic Halo Stars

    Full text link
    We present new abundance determinations of neutron-capture elements Ge, Zr, Os, Ir, and Pt in a sample of 11 metal-poor (-3.1 <= [Fe/H] <= -1.6) Galactic halo giant stars, based on Hubble Space Telescope UV and Keck I optical high-resolution spectroscopy. The stellar sample is dominated by r-process-rich stars such as the well-studied CS 22892-052 and bd+173248, but also includes the r-process-poor, bright giant HD 122563. Our results demonstrate that abundances of the 3rd r-process peak elements Os, Ir and Pt in these metal-poor halo stars are very well-correlated among themselves, and with the abundances of the canonical r-process element Eu (determined in other studies), thus arguing for a common origin or site for r-process nucleosynthesis of heavier (Z>56) elements. However, the large (and correlated) scatters of [Eu,Os,Ir,Pt/Fe] suggests that the heaviest neutron-capture r-process elements are not formed in all supernovae. In contrast, the Ge abundances of all program stars track their Fe abundances, very well. An explosive process on iron-peak nuclei (e.g., the alpha-rich freeze-out in supernovae), rather than neutron capture, appears to have been the dominant synthesis mechanism for this element at low metallicities -- Ge abundances seem completely uncorrelated with Eu.Comment: 35 pages, 5 tables, 7 figures; To appear in the Astrophysical Journa

    Lead Isotopes and Selected Metals in Ice from Law Dome, Antarctica

    Get PDF
    The isotopic composition. of Pb and the concentrations of Pb, Ba and Bi were measured in selected ice-core samples from Law Dome, East Antarctica, to a depth of 1196 m. The range of concentrations found in decontaminated ice was 0.03-1.5 pg g-1 for Pb, 0.9-6.1 pg g-1 for Ba and 0.4-17 fg g-1 for Bi, excluding the deepest sample which contained ∼1 ppm of rock dust. The abundances of all four stable lead isotopes were measured and gave 206Pb/207Pb ratios ≤ ∼1.23. A value of 208Pb/207Pb = 2.78 was measured in the deepest sample and is consistent with reported Pb isotope ratios of Antarctic granulites. Although the element concentrations in some samples were lower than have been reported elsewhere, geochemical and isotopic evidence indicated that a number of samples were contaminated with Pb not present in the original ice. However, it appears that the technical skills now available are approaching the level where careful sample selection, decontamination and analysis can yield accurate results for the concentration and isotopic composition of Pb in Earth\u27s purest naturally occurring ice
    corecore