376 research outputs found

    Why Ni3_3Al is an itinerant ferromagnet but Ni3_3Ga is not

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    Ni3_3Al and Ni3_3Ga are closely related materials on opposite sides of a ferromagnetic quantum critical point. The Stoner factor of Ni is virtually the same in both compounds and the density of states is larger in Ni3_3Ga. So, according to the Stoner theory, it should be more magnetic, and, in LDA calculations, it is. However, experimentally, it is a paramagnet, while Ni3_3Al is an itinerant ferromagnet. We show that the critical spin fluctuations are stronger than in Ni3_3Ga, due to a weaker q-dependence of the susceptibility, and this effect is strong enough to reverse the trend. The approach combines LDA calculations with the Landau theory and the fluctuation-dissipation theorem using the same momentum cut-off for both materials. The calculations provide evidence for strong, beyond LDA, spin fluctuations associated with the critical point in both materials, but stronger in Ni3_3Ga than in Ni3_3Al.Comment: replaced (incorrect version submitted

    Исследование и разработка гистерезисных электрических машин на основе деформируемого сплава Fe-Cr-Co

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    В ходе научно-квалификационной работы исследован материал ротора синхронного гистерезисного двигателя (СГД) из сплава 22Х15КА ГОСТ 24897-81. Получены динамические магнитные характеристики сплава на частотах перемагничивания от 50 Гц до 2 кГц. Представлены результаты исследования СГД в программной среде AnsysMaxwell 2D/3D.In the course of the scientific and qualifying work, the rotor material of the synchronous hysteresis motor from alloy 22Х15КА GOST 24897-81 was investigated. Dynamic magnetic characteristics of the alloy at the magnetization reversal frequencies from 50 Hz to 2 kHz are obtained. The results of the study of a synchronous hysteresis motor in the software environment of AnsysMaxwell 2D / 3D are presented

    Brengt ultraschone lucht op de OK meer veiligheid?

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    • Het ‘Beheersplan luchtbehandeling voor de operatieafdeling’ (2005) beschrijft het beheer en het onderhoud van de luchtbehandelingsinstallatie. • In dit Beheersplan wordt een norm voorgesteld voor luchtkwaliteit op operatieafdelingen type 1, die is aangenomen door de Nederlandse Orthopedische Vereniging, doch niet door andere wetenschappelijke verenigingen. • De Britse studie die ten grondslag ligt aan de voorgestelde norm voor luchtkwaliteit van operatieafdelingen type 1 is van 1982, en onvoldoende gecorrigeerd voor profylaxe met antibiotica. Die profylaxe leidt op zich namelijk ook al tot minder postoperatieve wondinfecties. • Recentere studies naar ultraschone lucht op de operatieafdeling laten geen infectiepreventief effect zien. • Er ligt een ta

    Diarrhoea in general practice: when should a Clostridium difficile infection be considered? Results of a nested case-control study

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    AbstractClostridium difficile infections (CDIs) are frequent in hospitals, but also seem to increase in the community. Here, we aim to determine the incidence of CDI in general practice and to evaluate current testing algorithms for CDI. Three Dutch laboratories tested all unformed faeces (12 714) for C. difficile when diagnostic testing (for any enteric pathogen) was requested by a general practitioner (GP). Additionally, a nested case-control study was initiated, including 152 CDI patients and 304 age and sex-matched controls. Patients were compared using weighted multivariable logistic regression. One hundred and ninety-four samples (1.5%) were positive for C. difficile (incidence 0.67/10 000 patient years). This incidence was comparable to that of Salmonella spp. Compared with diarrhoeal controls, CDI was associated with more severe complaints, underlying diseases, antibiotic use and prior hospitalization. In our study, GPs requested a test for C. difficile in 7% of the stool samples, thereby detecting 40% of all CDIs. Dutch national recommendations advise testing for C. difficile when prior antibiotic use or hospitalization is present (18% of samples). If these recommendations were followed, 61% of all CDIs would have been detected. In conclusion, C. difficile is relatively frequent in general practice. Currently, testing for C. difficile is rare and only 40% of CDI in general practice is detected. Following recommendations that are based on traditional risk factors for CDI, would improve detection of CDI

    Within-patient plasmid dynamics in Klebsiella pneumoniae during an outbreak of a carbapenemase-producing Klebsiella pneumoniae

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    INTRODUCTION: Knowledge of within-patient dynamics of resistance plasmids during outbreaks is important for understanding the persistence and transmission of plasmid-mediated antimicrobial resistance. During an outbreak of a Klebsiella pneumoniae carbapenemase-producing (KPC) K. pneumoniae, the plasmid and chromosomal dynamics of K. pneumoniae within-patients were investigated. METHODS: During the outbreak, all K. pneumoniae isolates of colonized or infected patients were collected, regardless of their susceptibility pattern. A selection of isolates was short-read and long-read sequenced. A hybrid assembly of the short-and long-read sequence data was performed. Plasmid contigs were extracted from the hybrid assembly, annotated, and within patient plasmid comparisons were performed. RESULTS: Fifteen K. pneumoniae isolates of six patients were short-read whole-genome sequenced. Whole-genome multi-locus sequence typing revealed a maximum of 4 allele differences between the sequenced isolates. Within patients 1 and 2 the resistance gene- and plasmid replicon-content did differ between the isolates sequenced. Long-read sequencing and hybrid assembly of 4 isolates revealed loss of the entire KPC-gene containing plasmid in the isolates of patient 2 and a recombination event between the plasmids in the isolates of patient 1. This resulted in two different KPC-gene containing plasmids being simultaneously present during the outbreak. CONCLUSION: During a hospital outbreak of a KPC-producing K. pneumoniae isolate, plasmid loss of the KPC-gene carrying plasmid and plasmid recombination was detected within the isolates from two patients. When investigating outbreaks, one should be aware that plasmid transmission can occur and the possibility of within- and between-patient plasmid variation needs to be considered

    Nonperturbative Evaluation of the Sphaleron Transition Rate

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    We review nonperturbative calculations of the rate of sphaleron transitions on the lattice in 1+11+1-dimensional field theories and introduce a way to perform the gauge-invariant Gibbs averages in the classical non-Abelian Higgs theories.Comment: 4 pages, uuencoded Postscript file. Talk given at NATO Advanced Research Workshop on Electroweak Physics and the Early Universe, Sintra, Portugal, 23-25 March 199

    Prevalence of Livestock-Associated MRSA in Communities with High Pig-Densities in The Netherlands

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    Contains fulltext : 124345.pdf (publisher's version ) (Open Access)BACKGROUND: Recently, livestock-associated methicillin-resistant Staphylococcus aureus CC398 has been discovered in animals, livestock farmers and retail meat. This cross-sectional study aimed to determine the spread to persons not in direct contact with livestock in areas with a high density of pig farms. METHODOLOGY/PRINCIPAL FINDINGS: With a random mailing in 3 selected municipalities in The Netherlands, adult persons were asked to fill in a questionnaire and to take a nose swab. In total, complete information was obtained on 583 persons. Of the 534 persons without livestock-contact, one was positive for MRSA (0.2%; 95% confidence interval, <0.01-1.2). Of the 49 persons who did indicate to be working at or living on a livestock farm, 13 were positive for MRSA (26.5%; 95% confidence interval, 16.1-40.4). All spa-types belonged to CC398. CONCLUSIONS/SIGNIFICANCE: Livestock-associated MRSA has a high prevalence in people with direct contact with animals. At this moment it has not spread from the farms into the community

    A global disorder of imprinting in the human female germ line

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    Imprinted genes are expressed differently depending on whether they are carried by a chromosome of maternal or paternal origin. Correct imprinting is established by germline-specific modifications; failure of this process underlies several inherited human syndromes. All these imprinting control defects are cis-acting, disrupting establishment or maintenance of allele-specific epigenetic modifications across one contiguous segment of the genome. In contrast, we report here an inherited global imprinting defect. This recessive maternal-effect mutation disrupts the specification of imprints at multiple, non-contiguous loci, with the result that genes normally carrying a maternal methylation imprint assume a paternal epigenetic pattern on the maternal allele. The resulting conception is phenotypically indistinguishable from an androgenetic complete hydatidiform mole, in which abnormal extra-embryonic tissue proliferates while development of the embryo is absent or nearly so. This disorder offers a genetic route to the identification of trans-acting oocyte factors that mediate maternal imprint establishment
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