2,746 research outputs found

    Suppression of spin-exchange relaxation in tilted magnetic fields within the geophysical range

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    We present a detailed experimental and theoretical study on the relaxation of spin coherence due to the spin-exchange mechanism arising in the electronic ground states of alkali-metal vapor atoms. As opposed to the well-explored formation of a stretched state in a longitudinal geometry (magnetic field parallel to the laser propagation direction) we employ adapted hyperfine-selective optical pumping in order to suppress spin-exchange relaxation. By comparing measurements of the intrinsic relaxation rate of the spin coherence in the ground state of cesium atoms with detailed density-matrix simulations we show that the relaxation due to spin-exchange collisions can be reduced substantially even in a tilted magnetic field of geomagnetic strength, the major application case of scalar magnetic surveying. This explains the observed striking improvement in sensitivity and further deepens the understanding of the light- narrowed Mx magnetometer, which was presented recently. Additionally, new avenues for investigating the dynamics in alkali-metal atoms governed by the spin-exchange interaction and interacting with arbitrary external fields open up

    The clinical picture of rheumatoid arthritis - the complex of three independent mechanisms

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    Shvaćanje o upalnoj bolesti kao jedino odgovornoj za složenu kliničku sliku reumatoidnog artritisa (a o čemu svjedoči i sám naziv bolesti) zapravo ne odgovara činjenicama. Naprotiv, našli smo i potvrdili postojanje triju, naoko međusobno neovisnih mehanizama, i tek njihova kombinacija može objasniti ukupnu kliničku sliku reumatoidnog artritisa. To su: 1. imunološki sinovitis, odgovoran za bol, otekline i zakočenost; 2. onkološki proces (“tumor-like proliferation”), odgovoran za razaranje zglobova; 3. primarno nekrotizirajući proces, odgovoran za (kadšto smrtonosna) razaranja u srcu i krvnim žilama.The assumption of inflamation as the only cause of the complex clinical picture of rheumatoid atrhritis does not correspond to facts. We have found and proven the existence of three seemingly unconnected mechanisms, and only their combination can account for the general clinical picture of rheumatoid arthritis. They are: 1. immunologic synovitis, responsible for pain, swelling and stiffnes; 2. oncological process (“tumor-like proliferation”), responsible for the destruction of joints; 3. Primary necrotizing process, responsible for the (sometimes lethal) destructions in the heart and blood vessels

    The clinical picture of rheumatoid arthritis - the complex of three independent mechanisms

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    Shvaćanje o upalnoj bolesti kao jedino odgovornoj za složenu kliničku sliku reumatoidnog artritisa (a o čemu svjedoči i sám naziv bolesti) zapravo ne odgovara činjenicama. Naprotiv, našli smo i potvrdili postojanje triju, naoko međusobno neovisnih mehanizama, i tek njihova kombinacija može objasniti ukupnu kliničku sliku reumatoidnog artritisa. To su: 1. imunološki sinovitis, odgovoran za bol, otekline i zakočenost; 2. onkološki proces (“tumor-like proliferation”), odgovoran za razaranje zglobova; 3. primarno nekrotizirajući proces, odgovoran za (kadšto smrtonosna) razaranja u srcu i krvnim žilama.The assumption of inflamation as the only cause of the complex clinical picture of rheumatoid atrhritis does not correspond to facts. We have found and proven the existence of three seemingly unconnected mechanisms, and only their combination can account for the general clinical picture of rheumatoid arthritis. They are: 1. immunologic synovitis, responsible for pain, swelling and stiffnes; 2. oncological process (“tumor-like proliferation”), responsible for the destruction of joints; 3. Primary necrotizing process, responsible for the (sometimes lethal) destructions in the heart and blood vessels

    Epidemiological and genetic characteristics of vancomycin-resistant Enterococcus faecium isolates in a University Children's Hospital in Germany: 2019 to 2020

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    Background: Vancomycin-resistant Enterococcus faecium (VREfm) strains are one of the most important pathogens causing nosocomial infections in Germany. Due to limited treatment options and an increased risk for acquisition in immunocompromised children, surveillance to monitor occurrence of VREfm in paediatric clinical facilities is of critical importance. Following an unusual accumulation of VREfm positive patients between April 2019 and August 2020 at Dr. von Hauner Children’s Hospital in Munich, Germany, our study aimed to identify dynamics and routes of transmission, and analyse the affected population in view of previously described host risk factors for VREfm colonisation or infection. Methods: The hospital database was used to collect epidemiological and clinical data of VREfm cases. Descriptive statistical analyses were conducted to outline patient characteristics and depict possible differences between VREfm-colonised and -infected children. An outbreak investigation determining genetic relatedness among VREfm isolates was performed by core genome multilocus sequence typing (cgMLST). To examine potential transmission pathways, results of genome analysis were compared with epidemiological and clinical data of VREfm positive patients. Results: VREfm acquisition was documented in a total of 33 children (< 18 years). Seven VREfm-colonised patients (21.2%), especially those with a haemato-oncological disease (4/7; p = 0.011), showed signs of clinical infection. cgMLST analysis revealed seven distinct clusters, demonstrating a possible connection within each clonal lineage. Additional eight singletons were identified. Comparison with epidemiological and clinical data provided strong evidence for a link between several VREfm positive patients within the hospital. Conclusions: A nosocomial spread—at least in part—was the most likely reason for the unusual accumulation of VREfm cases. The study highlights that there is a constant need to increase efforts in hygiene measures, infection control and antibiotic stewardship to combat VREfm transmission events within German paediatric hospitals. Continuous monitoring of adherence to respective policies might reduce the occurrence of clustered cases and prevent future outbreaks.Peer Reviewe

    Nucleon Spin Fluctuations and the Supernova Emission of Neutrinos and Axions

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    In the hot and dense medium of a supernova (SN) core, the nucleon spins fluctuate so fast that the axial-vector neutrino opacity and the axion emissivity are expected to be significantly modified. Axions with m_a\alt10^{-2}\,{\rm eV} are not excluded by SN~1987A. A substantial transfer of energy in neutrino-nucleon (νN\nu N) collisions is enabled which may alter the spectra of SN neutrinos relative to calculations where energy-conserving νN\nu N collisions had been assumed near the neutrinosphere.Comment: 8 pages. REVTeX. 2 postscript figures, can be included with epsf. Small modifications of the text, a new "Note Added", and three new references. To be published in Phys. Rev. Let

    Der Umgang mit Forschungsdaten an der Leibniz Universität Hannover. Auswertung einer Umfrage und ergänzender Interviews 2015/16

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    Im Kontext des Projekts „Entwicklung eines institutionellen Konzepts zum Forschungsdatenmanagement an der Leibniz Universität Hannover“ wurden 2015/16 eine universitätsinterne Online-Umfrage und ergänzende Interviews durchgeführt. Deren Ergebnisse ermöglichen einen Einblick in den derzeitigen Umgang mit Forschungsdaten und eine Abschätzung des Bedarfs an Beratung, Schulung und technischer Infrastruktur seitens des wissenschaftlichen Personals. In diesem Bericht werden die Daten präsentiert und ausgewertet
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