3,768 research outputs found

    Radiative corrections in processes at the SSC

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    We discuss radiative corrections for interactions in the SSC environment. Based on the theory of Yennie, Frautschi and Suura, we develop appropriate Monte Carlo event generators to compute the background electromagnetic radiation. Our results indicate that multiple-photon effects must be taken into account in the study of SSC physics such as Higgs decay.Comment: UTHEP-92-0901, 15 pages (incl. 3 figures), LaTeX (Talk presented at the XXXII Cracow School of Theoretical Physics, Zakopane, June 1992

    Evidence-based rules from family practice to inform family practice; The learning healthcare system case study on urinary tract infections

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    Background: Analysis of encounter data relevant to the diagnostic process sourced from routine electronic medical record (EMR) databases represents a classic example of the concept of a learning healthcare system (LHS). By collecting International Classification of Primary Care (ICPC) coded EMR data as part of the Transition Project from Dutch and Maltese databases (using the EMR TransHIS), data mining algorithms can empirically quantify the relationships of all presenting reasons for encounter (RfEs) and recorded diagnostic outcomes. We have specifically looked at new episodes of care (EoC) for two urinary system infections: simple urinary tract infection (UTI, ICPC code: U71) and pyelonephritis (ICPC code: U70). Methods: Participating family doctors (FDs) recorded details of all their patient contacts in an EoC structure using the ICPC, including RfEs presented by the patient, and the FDs' diagnostic labels. The relationships between RfEs and episode titles were studied using probabilistic and data mining methods as part of the TRANSFoRm project. Results: The Dutch data indicated that the presence of RfE's "Cystitis/Urinary Tract Infection", "Dysuria", "Fear of UTI", "Urinary frequency/urgency", "Haematuria", "Urine symptom/complaint, other" are all strong, reliable, predictors for the diagnosis "Cystitis/Urinary Tract Infection". The Maltese data indicated that the presence of RfE's "Dysuria", "Urinary frequency/urgency", "Haematuria" are all strong, reliable, predictors for the diagnosis "Cystitis/Urinary Tract Infection". The Dutch data indicated that the presence of RfE's "Flank/axilla symptom/complaint", "Dysuria", "Fever", "Cystitis/Urinary Tract Infection", "Abdominal pain/cramps general" are all strong, reliable, predictors for the diagnosis "Pyelonephritis". The Maltese data set did not present any clinically and statistically significant predictors for pyelonephritis. Conclusions: We describe clinically and statistically significant diagnostic associations observed between UTIs and pyelonephritis presenting as a new problem in family practice, and all associated RfEs, and demonstrate that the significant diagnostic cues obtained are consistent with the literature. We conclude that it is possible to generate clinically meaningful diagnostic evidence from electronic sources of patient data

    Eradication therapy for peptic ulcer disease in Helicobacter pylori-positive people

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    BACKGROUND: Peptic ulcer disease is the cause of dyspepsia in about 10% of people. Ninety-five percent of duodenal and 70% of gastric ulcers are associated with Helicobacter pylori. Eradication of H. pylori reduces the relapse rate of ulcers but the magnitude of this effect is uncertain. This is an update of Ford AC, Delaney B, Forman D, Moayyedi P. Eradication therapy for peptic ulcer disease in Helicobacter pylori-positive patients. Cochrane Database of Systematic Reviews 2006, Issue 2. Art. No.: CD003840. DOI: 10.1002/14651858.CD003840.pub4. OBJECTIVES: To assess the proportion of peptic ulcers healed and the proportion of participants who remained free from relapse with eradication therapy against placebo or other pharmacological therapies in H. pylori-positive people.To assess the proportion of participants that achieved complete relief of symptoms and improvement in quality of life scores.To compare the incidence of adverse effects/drop-outs (total number for each drug) associated with the different treatments.To assess the proportion of participants in whom successful eradication was achieved. SEARCH METHODS: In this update, we identified trials by searching the Cochrane Central Register of Controlled Trials (CENTRAL), Ovid MEDLINE (1950 to March 2016) and Ovid EMBASE (1980 to March 2016). To identify further relevant trials, we handsearched reference lists from trials selected by electronic searching, and published abstracts from conference proceedings from the United European Gastroenterology Week (published in Gut) and Digestive Disease Week (published in Gastroenterology). The search was last updated in March 2016. We contacted members of Cochrane Upper GI and Pancreatic Diseases, and experts in the field and asked them to provide details of outstanding clinical trials and any relevant unpublished materials. SELECTION CRITERIA: We analysed randomised controlled trials of short- and long-term treatment of peptic ulcer disease in H. pylori-positive adults. Participants received at least one week of H. pylori eradication compared with ulcer healing drug, placebo or no treatment. Trials were included if they reported assessment from two weeks onwards. DATA COLLECTION AND ANALYSIS: We collected data on ulcer healing, recurrence, relief of symptoms and adverse effects. We calculated the risk ratio (RR) with 95% confidence intervals (CI) using both fixed-effect and random-effects models with Review Manager software (RevMan 5.3) based on intention-to-treat analysis as far as possible. MAIN RESULTS: A total of 55 trials were included for one or more outcomes for this review.In duodenal ulcer healing, eradication therapy was superior to ulcer healing drug (UHD) (34 trials, 3910 participants, RR of ulcer persisting = 0.66, 95% confidence interval (CI) 0.58 to 0.76; 381/2286 (adjusted proportion: 12.4%) in eradication therapy plus UHD versus 304/1624 (18.7%) in UHD; low quality evidence) and no treatment (two trials, 207 participants, RR 0.37, 95% CI 0.26 to 0.53; 30/125 (adjusted proportion: 21.7%) in eradication therapy versus 48/82 (58.5%) in no treatment; low quality evidence).In gastric ulcer healing, the differences were imprecise between eradication therapy and UHD (15 trials, 1974 participants, RR 1.23, 95% CI 0.90 to 1.68; 220/1192 (adjusted proportion: 16.0%) in eradication therapy plus UHD versus 102/782 (13.0%) in UHD; very low quality evidence). In preventing duodenal ulcer recurrence the differences were imprecise between maintenance therapy with H.pylori eradication therapy and maintenance therapy with UHD (four trials, 319 participants, RR of ulcer recurring 0.73; 95% CI 0.42 to 1.25; 19/159 (adjusted proportion: 11.9%) in eradication therapy versus 26/160 (16.3%) in UHD; very low quality evidence), but eradication therapy was superior to no treatment (27 trials 2509 participants, RR 0.20, 95% CI 0.15 to 0.26; 215/1501 (adjusted proportion: 12.9%) in eradication therapy versus 649/1008 (64.4%) in no treatment; very low quality evidence).In preventing gastric ulcer recurrence, eradication therapy was superior to no treatment (12 trials, 1476 participants, RR 0.31, 95% CI 0.22 to 0.45; 116/697 (adjusted proportion: 16.3%) in eradication therapy versus 356/679 (52.4%) in no treatment; very low quality evidence). None of the trials reported proportion of people with gastric ulcer not healed after initial therapy between H.pylori eradication therapy and no active treatment or the proportion of people with recurrent gastric ulcer or peptic ulcers during maintenance therapy between H.pylori eradication therapy and ulcer healing drug therapy. AUTHORS' CONCLUSIONS: Adding a one to two-week course of H. pylori eradication therapy is an effective treatment for people with H. pylori-positive duodenal ulcer when compared to ulcer healing drugs alone and no treatment. H. pylori eradication therapy is also effective in preventing recurrence of duodenal and gastric ulcer compared to no treatment. There is currently no evidence that H. pylori eradication therapy is an effective treatment in people with gastric ulcer or that it is effective in preventing recurrence of duodenal ulcer compared to ulcer healing drug. However, confidence intervals were wide and significant benefits or harms of H. pylori eradication therapy in acute ulcer healing of gastric ulcers compared to no treatment, and in preventing recurrence of duodenal ulcers compared to ulcer healing drugs cannot be ruled out

    Temperature-Dependent Magnetoelectric Effect from First Principles

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    We show that nonrelativistic exchange interactions and spin fluctuations can give rise to a linear magnetoelectric effect in collinear antiferromagnets at elevated temperatures that can exceed relativistic magnetoelectric responses by more than 1 order of magnitude. We show how symmetry arguments, ab initio methods, and Monte Carlo simulations can be combined to calculate temperature-dependent magnetoelectric susceptibilities entirely from first principles. The application of our method to Cr2O3 gives quantitative agreement with experiment.

    Multiple Gluon Effects in q+qˉt+tˉ+Xq+\bar q\to t+\bar t + X at FNAL Energies: Semi-Analytical Results

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    We apply our Yennie-Frautschi-Suura exponentiated cross section formulas for the parton processes q + {^(} \bar q {^)}{^\prime} \ra q{^\prime}{^\prime} + {^(} \bar q {^)}{^\prime}{^\prime}{^\prime} + n(G) to the process q + \bar q \ra t + \bar t + n(G) at FNAL energies, where G is a QCD gluon. We use semi-analytical methods to compute the ratio rexp=σexp/σBr_{exp}=\sigma_{exp}/\sigma_B, where σexp\sigma_{exp} is our soft gluon YFS exponentiated cross section and σB\sigma_B is the Born cross section. For mt=0.176(0.199)m_t= 0.176(0.199)TeV, we get rexp=1.65(1.48)r_{exp}=1.65(1.48), respectively, for q=uq=u for example. These results are not inconsistent with the recent observations by CDF and D0.Comment: 6 pages, latex replaces postscript at archiver's reques

    Freshly Formed Dust in the Cassiopeia A Supernova Remnant as Revealed by the Spitzer Space Telescope

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    We performed Spitzer Infrared Spectrograph mapping observations covering nearly the entire extent of the Cassiopeia A supernova remnant (SNR), producing mid-infrared (5.5-35 micron) spectra every 5-10". Gas lines of Ar, Ne, O, Si, S and Fe, and dust continua were strong for most positions. We identify three distinct ejecta dust populations based on their continuum shapes. The dominant dust continuum shape exhibits a strong peak at 21 micron. A line-free map of 21 micron-peak dust made from the 19-23 micron range closely resembles the [Ar II], [O IV], and [Ne II] ejecta-line maps implying that dust is freshly formed in the ejecta. Spectral fitting implies the presence of SiO2, Mg protosilicates, and FeO grains in these regions. The second dust type exhibits a rising continuum up to 21 micron and then flattens thereafter. This ``weak 21 micron'' dust is likely composed of Al2O3 and C grains. The third dust continuum shape is featureless with a gently rising spectrum and is likely composed of MgSiO3 and either Al2O3 or Fe grains. Using the least massive composition for each of the three dust classes yields a total mass of 0.02 Msun. Using the most-massive composition yields a total mass of 0.054 Msun. The primary uncertainty in the total dust mass stems from the selection of the dust composition necessary for fitting the featureless dust as well as 70 micron flux. The freshly formed dust mass derived from Cas A is sufficient from SNe to explain the lower limit on the dust masses in high redshift galaxies.Comment: 8 figures: Accepted for the publication in Ap
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