610 research outputs found

    Assessing rainfall erosion risk in southern Saskatchewan from daily rainfall records

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    Non-Peer ReviewedA mean annual rainfall erosion index (R1daily) calculated from daily rainfall records satisfactorily compared with the mean annual erosion index (R) calculated using the more accepted method with hourly rainfall records. An R1daily contour map of Southern Saskatchewan was constructed from a greater number of weather stations keeping daily rainfall records compared to the R contour map constructed from very few stations that keep hourly rainfall records. It was concluded that the R1daily contour map provided a more reliable assessment of rainfall erosion potential than the R contour map because the former distinguished local areas with high values and interpolation of rainfall risk involved much shorter distances between point measurements. Since significant erosion requires a combination of rainfall detachment as well as runoff, a runoff model that operated from daily climatic records was used to determine which days with rainfall also produced runoff. The runoff model was run for 62 stations in southern Saskatchewan and only days that produced runoff were included in the annual erosion index total. This effective erosion index (Reff) varied from 3.4 to 83.9 % of R1daily and was particularly sensitive to soil texture. Heavy-textured soils were, on average, more than four times as susceptible to water erosion than light-textured soils. It should be noted that the analysis does not include the effects of slope length and steepness, the crop canopy nor soil erodibility

    Steklov problem on differential forms

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    In this paper we study spectral properties of Dirichlet-to-Neumann map on differential forms obtained by a slight modification of the definition due to Belishev and Sharafutdinov. The resulting operator Λ\Lambda is shown to be self-adjoint on the subspace of coclosed forms and to have purely discrete spectrum there.We investigate properies of eigenvalues of Λ\Lambda and prove a Hersch-Payne-Schiffer type inequality relating products of those eigenvalues to eigenvalues of Hodge Laplacian on the boundary. Moreover, non-trivial eigenvalues of Λ\Lambda are always at least as large as eigenvalues of Dirichlet-to-Neumann map defined by Raulot and Savo. Finally, we remark that a particular case of pp-forms on the boundary of 2p+22p+2-dimensional manifold shares a lot of important properties with the classical Steklov eigenvalue problem on surfaces.Comment: 18 page

    Web-Based Educational Intervention for Patients With Uninvestigated Dyspepsia Referred for Upper Gastrointestinal Tract Endoscopy:A Randomized Clinical Trial

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    Item does not contain fulltextIMPORTANCE: Diagnostic yield of upper gastrointestinal (GI) tract endoscopy for uninvestigated dyspepsia is low, and its clinical implications are limited. There is an unmet need for better strategies to reduce the volume of upper GI tract endoscopic procedures for dyspepsia. OBJECTIVE: To study the effectiveness of a web-based educational intervention as a tool to reduce upper GI tract endoscopy in uninvestigated dyspepsia. DESIGN, SETTING, AND PARTICIPANTS: This open-label, multicenter, randomized clinical trial enrolled participants between November 1, 2017, and March 31, 2019, with follow-up 52 weeks after randomization, at 4 teaching hospitals in the Netherlands. Participants included patients with uninvestigated dyspeptic symptoms who were referred for upper GI tract endoscopy by their general health care clinician without prior consultation of a gastroenterologist. A total of 119 patients, aged 18 to 69 years, were included. Patients were excluded if any of the following red flag symptoms were present: (indirect) signs of upper GI tract hemorrhage (hematemesis, melena, hematochezia, or anemia), unintentional weight loss of 5% or higher of normal body weight during a period of 6 to 12 months, persistent vomiting, dysphagia, or jaundice. INTERVENTIONS: Patients were randomly assigned (1:1) to education (intervention) or upper GI tract endoscopy (control). Education consisted of a self-managed web-based educational intervention, containing information on gastric function, dyspepsia, and upper GI tract endoscopy. MAIN OUTCOMES AND MEASURES: Difference in the proportion of upper GI tract endoscopy procedures between those who received access to the web-based educational intervention and those who did not at 12 weeks and 52 weeks after randomization, analyzed in the intention-to-treat population. Secondary outcomes included quality of life (Nepean Dyspepsia Index) and symptom severity (Patient Assessment of Gastrointestinal Disorders Symptom Severity Index) measured at baseline and 12 weeks. RESULTS: Of 119 patients included (median age, 48 years [interquartile range, 37-56 years]; 48 men [40%]), 62 were randomized to web-based education (intervention) and 57 to upper GI tract endoscopy (control). Significantly fewer patients compared with controls underwent upper GI tract endoscopy after using the web-based educational intervention: 24 (39%) vs 47 (82%) (relative risk, 0.46; 95% CI, 0.33-0.64; P < .001). Symptom severity and quality of life improved equivalently in both groups. One additional patient in the intervention group required upper GI tract endoscopy during follow-up. CONCLUSIONS AND RELEVANCE: Findings of this study indicate that web-based patient education is an effective tool to decrease the need for upper GI tract endoscopy in uninvestigated dyspepsia. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03205319

    Multi-score Learning for Affect Recognition: the Case of Body Postures

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    An important challenge in building automatic affective state recognition systems is establishing the ground truth. When the groundtruth is not available, observers are often used to label training and testing sets. Unfortunately, inter-rater reliability between observers tends to vary from fair to moderate when dealing with naturalistic expressions. Nevertheless, the most common approach used is to label each expression with the most frequent label assigned by the observers to that expression. In this paper, we propose a general pattern recognition framework that takes into account the variability between observers for automatic affect recognition. This leads to what we term a multi-score learning problem in which a single expression is associated with multiple values representing the scores of each available emotion label. We also propose several performance measurements and pattern recognition methods for this framework, and report the experimental results obtained when testing and comparing these methods on two affective posture datasets

    Spin-polarized transport and Andreev reflection in semiconductor/superconductor hybrid structures

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    We show that spin-polarized electron transmission across semiconductor/superconductor (Sm/S) hybrid structures depends sensitively on the degree of spin polarization as well as the strengths of potential and spin-flip scattering at the interface. We demonstrate that increasing the Fermi velocity mismatch in the Sm and S regions can lead to enhanced junction transparency in the presence of spin polarization. We find that the Andreev reflection amplitude at the superconducting gap energy is a robust measure of the spin polarization magnitude, being independent of the strengths of potential and spin-flip scattering and the Fermi velocity of the superconductor.Comment: 4 pages, 2 figure

    Evolution of costs of inflammatory bowel disease over two years of follow-up

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    Background: With the increasing use of anti-TNF therapy in inflammatory bowel disease (IBD), a shift of costs has been observed with medication costs replacing hospitalization and surgery as major cost driver. We aimed to explore the evolution of IBD-related costs over two years of follow-up. Methods and Findings: In total 1,307 Crohn's disease (CD) patients and 915 ulcerative colitis (UC) patients were prospectively followed for two years by three-monthly web-based questionnaires. Changes of healthcare costs, productivity costs and out-of-pocket costs over time were assessed using mixed model analysis. Multivariable logistic regression analysis was used to identify costs drivers. In total 737 CD patients and 566 UC were included. Total costs were stable over two years of follow-up, with annual total costs of € 7,835 in CD and € 3,600 in UC. However, within healthcare costs, the proportion of anti-TNF therapy-related costs increased from 64% to 72% in CD (p<0.01) and from 31% to 39% in UC (p < 0.01). In contrast, the proportion of hospitalization costs decreased from 19% to 13% in CD (p<0.01), and 22% to 15% in UC (p < 0.01). Penetrating disease course predicted an increase of healthcare costs (adjusted odds ratio (adj. OR) 1.95 (95% CI 1.02-3.37) in CD and age <40 years in UC (adj. OR 4.72 (95% CI 1.61-13.86)). Conclusions: BD-related costs remained stable over two years. However, the proportion of anti-TNFrelated healthcare costs increased, while hospitalization costs decreased. Factors associated with increased costs were penetrating disease course in CD and age <40 in UC

    First Measurement of Z/gamma* Production in Compton Scattering of Quasi-real Photons

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    We report the first observation of Z/gamma* production in Compton scattering of quasi-real photons. This is a subprocess of the reaction e+e- to e+e-Z/gamma*, where one of the final state electrons is undetected. Approximately 55 pb-1 of data collected in the year 1997 at an e+e- centre-of-mass energy of 183 GeV with the OPAL detector at LEP have been analysed. The Z/gamma* from Compton scattering has been detected in the hadronic decay channel. Within well defined kinematic bounds, we measure the product of cross-section and Z/gamma* branching ratio to hadrons to be (0.9+-0.3+-0.1) pb for events with a hadronic mass larger than 60 GeV, dominated by (e)eZ production. In the hadronic mass region between 5 GeV and 60 GeV, dominated by (e)egamma* production, this product is found to be (4.1+-1.6+-0.6) pb. Our results agree with the predictions of two Monte Carlo event generators, grc4f and PYTHIA.Comment: 18 pages, LaTeX, 5 eps figures included, submitted to Physics Letters

    Search for Higgs Bosons in e+e- Collisions at 183 GeV

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    The data collected by the OPAL experiment at sqrts=183 GeV were used to search for Higgs bosons which are predicted by the Standard Model and various extensions, such as general models with two Higgs field doublets and the Minimal Supersymmetric Standard Model (MSSM). The data correspond to an integrated luminosity of approximately 54pb-1. None of the searches for neutral and charged Higgs bosons have revealed an excess of events beyond the expected background. This negative outcome, in combination with similar results from searches at lower energies, leads to new limits for the Higgs boson masses and other model parameters. In particular, the 95% confidence level lower limit for the mass of the Standard Model Higgs boson is 88.3 GeV. Charged Higgs bosons can be excluded for masses up to 59.5 GeV. In the MSSM, mh > 70.5 GeV and mA > 72.0 GeV are obtained for tan{beta}>1, no and maximal scalar top mixing and soft SUSY-breaking masses of 1 TeV. The range 0.8 < tanb < 1.9 is excluded for minimal scalar top mixing and m{top} < 175 GeV. More general scans of the MSSM parameter space are also considered.Comment: 49 pages. LaTeX, including 33 eps figures, submitted to European Physical Journal
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