757 research outputs found

    The signature of a double quantum-dot structure in the I-V characteristics of a complex system

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    We demonstrate that by carefully analyzing the temperature dependent characteristics of the I-V measurements for a given complex system it is possible to determine whether it is composed of a single, double or multiple quantum-dot structure. Our approach is based on the orthodox theory for a double-dot case and is capable of simulating I-V characteristics of systems with any resistance and capacitance values and for temperatures corresponding to thermal energies larger than the dot level spacing. We compare I-V characteristics of single-dot and double-dot systems and show that for a given measured I-V curve considering the possibility of a second dot is equivalent to decreasing the fit temperature. Thus, our method allows one to gain information about the structure of an experimental system based on an I-V measurement.Comment: 12 pages 7 figure

    Zero bias anomaly in a two dimensional granular insulator

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    We compare tunneling density of states (TDOS) into two ultrathin Ag films, one uniform and one granular, for different degrees of disorder. The uniform film shows a crossover from Altshuler-Aronov (AA) zero bias anomaly to Efros Shklovskii (ES) like Coulomb gap as the disorder is increased. The granular film, on the other hand, exhibits AA behavior even deeply in the insulating regime. We analyze the data and find that granularity introduces a new regime for the TDOS. While the conductivity is dominated by hopping between clusters of grains and is thus insulating, the TDOS probes the properties of an individual cluster which is "metallic".Comment: 4 pages, 4 figure

    Projected effects of tobacco smoking on worldwide tuberculosis control: mathematical modelling analysis

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    Objectives Almost 20% of people smoke tobacco worldwide—a percentage projected to rise in many poor countries. Smoking has been linked to increased individual risk of tuberculosis infection and mortality, but it remains unclear how these risks affect population-wide tuberculosis rates

    Prevalence of paratuberculosis in the dairy goat and dairy sheep industries in Ontario, Canada

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    A cross-sectional study was undertaken (October 2010 to August 2011) to estimate the prevalence of paratuberculosis in the small ruminant dairy industries in Ontario, Canada. Blood and feces were sampled from 580 goats and 397 sheep (lactating and 2 y of age or older) that were randomly selected from 29 randomly selected dairy goat herds and 21 convenience-selected dairy sheep flocks. Fecal samples were analyzed using bacterial culture (BD BACTEC MGIT 960) and polymerase chain reaction (Tetracore); serum samples were tested with the Prionics Parachek enzyme-linked immunosorbent assay (ELISA). Using 3-test latent class Bayesian models, true farm-level prevalence was estimated to be 83.0% [95% probability interval (PI): 62.6% to 98.1%] for dairy goats and 66.8% (95% PI: 41.6% to 91.4%) for dairy sheep. The within-farm true prevalence for dairy goats was 35.2% (95% PI: 23.0% to 49.8%) and for dairy sheep was 48.3% (95% PI: 27.6% to 74.3%). These data indicate that a paratuberculosis control program for small ruminants is needed in Ontario

    Comparison of systolic blood pressure measurements by auscultation and visual manometer needle jump

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    International Journal of Exercise Science 12(2): 214-220, 2019. Purpose: This study was designed to investigate differences in systolic blood pressure measurements as obtained through auscultation and observation of the visual jump on the manometer. Methods: Men (n = 21; 26.9 ± 7.4 yrs) and women (n = 22; 29.3 ± 13.9 yrs) volunteered to have resting systolic blood pressure (SBP) assessments. During the same cardiac inflation-deflation cycle of traditional sphygmomanometry, the initial visual jump of the manometer needle and first Korotkoff sound heard were recorded. Duplicate assessments were made in each arm with 30 sec between intra-arm trials. Results: Paired t-test results indicated there were no within-method differences between arms for visual jump (R: 132.1 ± 11.3; L: 131.8 ± 10.5 mmHg) or auscultation (R: 116.8 ± 9.0; L: 113.5 ± 8.8 mmHg). There were methodological differences within arm with visual jump being the higher of the two (right: t(42) = -12.69; left: t(42) = -11.37; p \u3c .001). Conclusion: If visual jump determination of SBP cannot be avoided, re-assessment using a more traditional method (i.e. auscultation) is recommended

    Parallel Evaluation of Multi-join Queries

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    A number of execution strategies for parallel evaluation of multi-join queries have been proposed in the literature. In this paper we give a comparative performance evaluation of four execution strategies by implementing all of them on the same parallel database system, PRISMA/DB. Experiments have been done up to 80 processors. These strategies, coming from the literature, are named: Sequential Parallel, Synchronous Execution, Segmented Right-Deep, and Full Parallel. Based on the experiments clear guidelines are given when to use which strategy. This is an extended abstract; the full paper appeared in Proc. ACM SIGMOD'94, Minneapolis, Minnesota, May 24–27, 199

    An unusual cause of gastric outlet obstruction during percutaneous endogastric feeding: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>The differential diagnoses of acute abdomen in children include common and rare pathologies. Within this list, different types of bezoars causing gastrointestinal obstruction have been reported in the literature and different methods of management have been described. The aim of this article is to highlight a rare presentation of lactobezoars following prolonged percutaneous endoscopic gastrostomy feeding and its successful surgical management.</p> <p>Case presentation</p> <p>A 16-year-old boy was admitted to a paediatric ward with abdominal distension and high output from his permanent gastrostomy feeding tube, with drainage of bilious fluids. The clinical, radiological and endoscopical examinations were suggestive of partial duodenal obstruction with multiple bezoars in the stomach and duodenum. Gastrojejunostomy was performed after the removal of 14 bezoars. The child had an uneventful postoperative course and was discharged on the sixth postoperative day in a stable condition.</p> <p>Conclusion</p> <p>Lactobezoars should be included in the differential diagnosis of acute abdominal pain in patients with percutaneous endogastric feeding. Endoscopy is important in making the diagnosis of this surgical condition of the upper gastrointestinal tract in a child.</p
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