2,801 research outputs found

    On 32-GHz cryogenically cooled HEMT low-noise amplifiers

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    The cryogenic noise temperature performance of a two-stage and a three-stage 32 GHz High Electron Mobility Transistor (HEMT) amplifier was evaluated. The amplifiers employ 0.25 micrometer conventional AlGaAs/GaAs HEMT devices, hybrid matching input and output microstrip circuits, and a cryogenically stable dc biasing network. The noise temperature measurements were performed in the frequency range of 31 to 33 GHz over a physical temperature range of 300 K down to 12 K. Across the measurement band, the amplifiers displayed a broadband response, and the noise temperature was observed to decrease by a factor of 10 in cooling from 300 K to 15 K. The lowest noise temperature measured for the two-stage amplifier at 32 GHz was 35 K with an associated gain of 16.5 dB, while the three-stage amplifier measured 39 K with an associated gain of 26 dB. It was further observed that both amplifiers were insensitive to light

    Long-lived neutral-kaon flux measurement for the KOTO experiment

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    The KOTO (K0K^0 at Tokai) experiment aims to observe the CP-violating rare decay KLπ0ννˉK_L \rightarrow \pi^0 \nu \bar{\nu} by using a long-lived neutral-kaon beam produced by the 30 GeV proton beam at the Japan Proton Accelerator Research Complex. The KLK_L flux is an essential parameter for the measurement of the branching fraction. Three KLK_L neutral decay modes, KL3π0K_L \rightarrow 3\pi^0, KL2π0K_L \rightarrow 2\pi^0, and KL2γK_L \rightarrow 2\gamma were used to measure the KLK_L flux in the beam line in the 2013 KOTO engineering run. A Monte Carlo simulation was used to estimate the detector acceptance for these decays. Agreement was found between the simulation model and the experimental data, and the remaining systematic uncertainty was estimated at the 1.4\% level. The KLK_L flux was measured as (4.183±0.017stat.±0.059sys.)×107(4.183 \pm 0.017_{\mathrm{stat.}} \pm 0.059_{\mathrm{sys.}}) \times 10^7 KLK_L per 2×10142\times 10^{14} protons on a 66-mm-long Au target.Comment: 27 pages, 16 figures. To be appeared in Progress of Theoretical and Experimental Physic

    The Value of Intraoperative Parathyroid Hormone Monitoring in Localized Primary Hyperparathyroidism: A Cost Analysis

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    Minimally invasive parathyroidectomy (MIP) is the preferred approach to primary hyperparathyroidism (PHPT) when a single adenoma can be localized preoperatively. The added value of intraoperative parathyroid hormone (IOPTH) monitoring remains debated because its ability to prevent failed parathyroidectomy due to unrecognized multiple gland disease (MGD) must be balanced against assay-related costs. We used a decision tree and cost analysis model to examine IOPTH monitoring in localized PHPT. Literature review identified 17 studies involving 4,280 unique patients, permitting estimation of base case costs and probabilities. Sensitivity analyses were performed to evaluate the uncertainty of the assumptions associated with IOPTH monitoring and surgical outcomes. IOPTH cost, MGD rate, and reoperation cost were varied to evaluate potential cost savings from IOPTH. The base case assumption was that in well-localized PHPT, IOPTH monitoring would increase the success rate of MIP from 96.3 to 98.8%. The cost of IOPTH varied with operating room time used. IOPTH reduced overall treatment costs only when total assay-related costs fell below 110percase.InaccuratelocalizationandhighreoperationcostbothindependentlyincreasedthevalueofIOPTHmonitoring.TheIOPTHstrategywascostsavingwhentherateofunrecognizedMGDexceeded6110 per case. Inaccurate localization and high reoperation cost both independently increased the value of IOPTH monitoring. The IOPTH strategy was cost saving when the rate of unrecognized MGD exceeded 6% or if the cost of reoperation exceeded 12,000 (compared with initial MIP cost of $3733). Setting the positive predictive value of IOPTH at 100% and reducing the false-negative rate to 0% did not substantially alter these findings. Institution-specific factors influence the value of IOPTH. In this model, IOPTH increased the cure rate marginally while incurring approximately 4% additional cost

    Transport of Babesia venatorum-infected Ixodes ricinus to Norway by northward migrating passerine birds

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    <p>Abstract</p> <p>Background</p> <p>Bovine babesiosis is regarded as a limited health problem for Norwegian cows, and the incidence has decreased markedly since the 1930s. Rare cases of babesiosis in splenectomised humans from infection with <it>Babesia divergens </it>and <it>B.venatorum </it>have been described. The objective of this study was to determine whether birds can introduce <it>Babesia</it>-infected ticks. There are between 30 and 85 million passerine birds that migrate to Norway every spring.</p> <p>Methods</p> <p>Passerine birds were examined for ticks at four bird observatories along the southern Norwegian coast during the spring migrations of 2003, 2004 and 2005. The presence of <it>Babesia </it>was detected in the nymphs of <it>Ixodes ricinus </it>by real-time PCR. Positive samples were confirmed using PCR, cloning and phylogenetic analyses.</p> <p>Results</p> <p>Of 512 ticks examined, real-time PCR revealed five to be positive (1.0%). Of these, four generated products that indicated the presence of <it>Babesia </it>spp.; each of these were confirmed to be from <it>Babesia venatorum </it>(EU1). Two of the four <it>B. venatorum</it>-positive ticks were caught from birds having an eastern migratory route (<it>P</it>< 0.001).</p> <p>Conclusions</p> <p>Birds transport millions of ticks across the North Sea, the Skagerrak and the Kattegat every year. Thus, even with the low prevalence of <it>Babesia</it>-infected ticks, a substantial number of infected ticks will be transported into Norway each year. Therefore, there is a continuous risk for introduction of new <it>Babesia </it>spp. into areas where <it>I. ricinus </it>can survive.</p

    Babesia spp. in ticks and wildlife in different habitat types of Slovakia

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    Background: Babesiosis is an emerging and potentially zoonotic disease caused by tick-borne piroplasmids of the Babesia genus. New genetic variants of piroplasmids with unknown associations to vectors and hosts are recognized. Data on the occurrence of Babesia spp. in ticks and wildlife widen the knowledge on the geographical distribution and circulation of piroplasmids in natural foci. Questing and rodent-attached ticks, rodents, and birds were screened for the presence of Babesia-specific DNA using molecular methods. Spatial and temporal differences of Babesia spp. prevalence in ticks and rodents from two contrasting habitats of Slovakia with sympatric occurrence of Ixodes ricinus and Haemaphysalis concinna ticks and co-infections of Candidatus N. mikurensis and Anaplasma phagocytophilum were investigated. Results: Babesia spp. were detected in 1.5 % and 6.6 % of questing I. ricinus and H. concinna, respectively. Prevalence of Babesia-infected I. ricinus was higher in a natural than an urban/suburban habitat. Phylogenetic analysis showed that Babesia spp. from I. ricinus clustered with Babesia microti, Babesia venatorum, Babesia canis, Babesia capreoli/Babesia divergens, and Babesia odocoilei. Babesia spp. amplified from H. concinna segregated into two monophyletic clades, designated Babesia sp. 1 (Eurasia) and Babesia sp. 2 (Eurasia), each of which represents a yet undescribed novel species. The prevalence of infection in rodents (with Apodemus flavicollis and Myodes glareolus prevailing) with B. microti was 1.3 % in an urban/suburban and 4.2 % in a natural habitat. The majority of infected rodents (81.3 %) were positive for spleen and blood and the remaining for lungs and/or skin. Rodent-attached I. ricinus (accounting for 96.3 %) and H. concinna were infected with B. microti, B. venatorum, B. capreoli/B. divergens, Babesia sp. 1 (Eurasia), and Babesia sp. 2 (Eurasia). All B. microti and B. venatorum isolates were identical to known zoonotic strains from Europe. Less than 1.0 % of Babesia-positive ticks and rodents carried Candidatus N. mikurensis or A. phagocytophilum.Inst. de PatobiologíaFil: Hamsikova, Zuzana. Slovak Academy of Sciences. Institute of Zoology; EslovaquiaFil: Kazimirová, Mária. Slovak Academy of Sciences. Institute of Zoology; EslovaquiaFil: Harustiakova, Danka. Masaryk University. Faculty of Medicine and Faculty of Science, Institute of Biostatistics and Analyses; República ChecaFil: Mahrikova, Lenka. Slovak Academy of Sciences. Institute of Zoology; EslovaquiaFil: Slovak, Mirko. Slovak Academy of Sciences. Institute of Zoology; EslovaquiaFil: Berthova, Lenka. Slovak Academy of Sciences. Biomedical Research Center. Institute of Virology; EslovaquiaFil: Kocianova, Elena. Slovak Academy of Sciences. Biomedical Research Center. Institute of Virology; EslovaquiaFil: Schnittger, Leonhard. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Patobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
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