2,222 research outputs found
Methods for evaluating the effect modification in the observational studies: A retrospective analysis on the impact of simvastatina and ezetimibe and statins on acute myocardial infarction
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An examination of the relationships between causal attributions for smoking and smokers\u27 treatment seeking and quit intentions: A structural equation modeling approach
With increasing knowledge of the role that genetics play in the development and treatment of nicotine dependence, it is expected that in the future smoking cessation treatment will be able to be tailored to a smoker\u27s genetic profile. Despite anticipated benefits such as improved quit rates, concerns have been raised about the impact of genetic testing results on perceived control over smoking, motivation to quit, and treatment seeking behaviour. One potential mediator of such outcomes are causal attributions, the causal explanations people form for behaviours and events, which evidence suggests can be altered by genetic testing feedback. The purpose of the current study was to perform a comprehensive assessment of causal attributions for current smoking and to examine the associations between these attributions and variables expected to predict future smoking cessation behaviour. Two structural equation models were tested that represented a series of hypotheses regarding how causal attributions influence intentions to quit smoking and intentions to seek smoking cessation treatment, via beliefs about perceived control over smoking and perceived effectiveness of treatment. Causal attributions were represented by causal types (biological, psychological, social, and stress) in one model and by causal dimensions (locus of causality, stability, internal control, and external control) in a second model; both models were otherwise identical. Participants were 418 current daily smokers in Ontario, Canada, that had previously participated in the Ontario Health Study. Overall, participants most frequently attributed their smoking to habit, addiction, and/or stress, while attributions to genetics were among the least frequent. Additionally, knowledge that genetics play a role in determining level of addiction to nicotine was not pervasive. Study findings supported the hypothesized model in which causal dimensions directly predicted level of perceived control over smoking (personal or via treatment), which in turn predicted perceived effectiveness of pharmacological and psychosocial smoking cessation treatments, intentions to quit smoking, and intentions to seek cessation treatment. Results failed to find similar associations with causal types. Current findings can be applied to future research on the effects of providing genetic testing feedback to smokers in clinical settings, and may have wider applicability to other health threats
The mantle wedge's transient 3-D flow regime and thermal structure
Arc volcanism, volatile cycling, mineralization, and continental crust formation are likely regu-lated by the mantle wedge’s flow regime and thermal structure. Wedge flow is often assumed to follow a regular corner-flow pattern. However, studies that incorporate a hydrated rheology and thermal buoyancy predict internal small-scale-convection (SSC). Here, we systematically explore mantle-wedge dynamics in 3-
D simulations. We find that longitudinal ‘‘Richter-rolls’’ of SSC (with trench-perpendicular axes) commonly occur if wedge hydration reduces viscosities to ≤1 ∙ 10^19 Pa s, although transient transverse rolls (with trench-parallel axes) can dominate at viscosities of ~5 ∙ 10^18 - 1 ∙ 10^19 Pa s. Rolls below the arc and back arc differ. Subarc rolls have similar trench-parallel and trench-perpendicular dimensions of 100–150 km and evolve on a 1–5 Myr time-scale. Subback-arc instabilities, on the other hand, coalesce into elongated sheets, usually with a preferential trench-perpendicular alignment, display a wavelength of 150–400 km and vary on a 5–10 Myr time scale. The modulating influence of subback-arc ridges on the subarc system increases
with stronger wedge hydration, higher subduction velocity, and thicker upper plates. We find that trench-parallel averages of wedge velocities and temperature are consistent with those predicted in 2-D models. However, lithospheric thinning through SSC is somewhat enhanced in 3-D, thus expanding hydrous melting regions and shifting dehydration boundaries. Subarc Richter-rolls generate time-dependent trench-parallel temperature variations of up to ~150 K, which exceed the transient 50–100 K variations predicted in 2-D
and may contribute to arc-volcano spacing and the variable seismic velocity structures imaged beneath some arcs
Transesophageal dipyridamole echocardiography for diagnosis of coronary artery disease.
The value of transthoracic dipyridamole echocardiography has been extensively documented. However, in some patients, because of a poor acoustic window, the rest transthoracic examination is not always feasible and the transesophageal approach is more convenient. Therefore, transesophageal echocardiography with high dose dipyridamole (up to 0.84 mg/kg body weight over 10 min) was performed in 32 patients in whom the transthoracic dipyridamole test either was not feasible (n = 29) or yielded ambiguous results (n = 3). The transesophageal echocardiographic test results were considered abnormal when new dipyridamole-induced regional wall motion abnormalities were observed. All 32 patients underwent coronary angiography; significant coronary artery disease was defined as greater than or equal to 70% lumen diameter narrowing in at least one major vessel. All patients also performed a bicycle exercise test 1 day before transesophageal dipyridamole echocardiography. Transesophageal stress studies were completed in all patients, with a maximal imaging time (in tests with a negative result) of 20 min. No side effects or intolerance to drug or transducer was observed. The left ventricle was always visualized in the four-chamber and transgastric short-axis views. High quality two-dimensional echocardiographic images were obtained in all patients both at rest and at peak dipyridamole infusion and were digitally analyzed in a quad-screen format. Coronary angiography showed coronary artery obstruction in 24 patients: 6 had single-, 9 double- and 9 triple-vessel disease. The transesophageal dipyridamole test showed a specificity of 100% and an overall sensitivity of 92%. The sensitivity of this test for single-, double- and triple-vessel disease was 67%, 100% and 100%, respectivel
Long term effectiveness on prescribing of two multifaceted educational interventions: Results of two large scale randomized cluster trials
Introduction: Information on benefits and risks of drugs is a key element affecting doctors' prescribing decisions. Outreach visits promoting independent information have proved moderately effective in changing prescribing behaviours. Objectives: Testing the short and long-term effectiveness on general practitioners' prescribing of small groups meetings led by pharmacists. Methods: Two cluster open randomised controlled trials (RCTs) were carried out in a large scale NHS setting. Ad hoc prepared evidence based material were used considering a therapeutic area approach - TEA, with information materials on osteoporosis or prostatic hyperplasia - and a single drug oriented approach - SIDRO, with information materials on me-too drugs of 2 different classes: barnidipine or prulifloxacin. In each study, all 115 Primary Care Groups in a Northern Italy area (2.2 million inhabitants, 1737 general practitioners) were randomised to educational small groups meetings, in which available evidence was provided together with drug utilization data and clinical scenarios. Main outcomes were changes in the six-months prescription of targeted drugs. Longer term results (24 and 48 months) were also evaluated. Results: In the TEA trial, one of the four primary outcomes showed a reduction (prescription of alfuzosin compared to tamsulosin and terazosin in benign prostatic hyperplasia: prescribing ratio -8.5%, p = 0.03). Another primary outcome (prescription of risedronate) showed a reduction at 24 and 48 months (-7.6%, p = 0.02; and -9,8%, p = 0.03), but not at six months (-5.1%, p = 0.36). In the SIDRO trial both primary outcomes showed a statistically significant reduction (prescription of barnidipine -9.8%, p = 0.02; prescription of prulifloxacin -11.1%, p = 0.04), which persisted or increased over time. Interpretation: These two cluster RCTs showed the large scale feasibility of a complex educational program in a NHS setting, and its potentially relevant long-term impact on prescribing habits, in particular when focusing on a single drug. National Health systems should invest in independent drug information programs. Trial Registration: Controlled-Trials.com ISRCTN05866587
Design and Test of a Forward Neutron Calorimeter for the ZEUS Experiment
A lead scintillator sandwich sampling calorimeter has been installed in the
HERA tunnel 105.6 m from the central ZEUS detector in the proton beam
direction. It is designed to measure the energy and scattering angle of
neutrons produced in charge exchange ep collisions. Before installation the
calorimeter was tested and calibrated in the H6 beam at CERN where 120 GeV
electrons, muons, pions and protons were made incident on the calorimeter. In
addition, the spectrum of fast neutrons from charge exchange proton-lucite
collisions was measured. The design and construction of the calorimeter is
described, and the results of the CERN test reported. Special attention is paid
to the measurement of shower position, shower width, and the separation of
electromagnetic showers from hadronic showers. The overall energy scale as
determined from the energy spectrum of charge exchange neutrons is compared to
that obtained from direct beam hadrons.Comment: 45 pages, 22 Encapsulated Postscript figures, submitted to Nuclear
Instruments and Method
Liver transplantation for hepatocellular carcinoma: further considerations on selection criteria
The selection criteria in liver transplantation for HCC are a matter of debate. We reviewed our series, comparing two periods: before and after 1996, when we started to apply the Milan criteria. The study population was composed of patients with a preoperative diagnosis of HCC, confirmed by the pathological report and with a survival of > 1 year. Preoperative staging as revealed by radiological imagining was distinguished from postoperative data, including the variable of tumor volume. After 1996 tumor recurrences significantly decreased (6 out of 15 cases, 40% vs. 3 out of 48, 6.3%, P < .005) and 5-year patient survival improved (42% vs. 83%, P < .005). Not meeting the Milan criteria was significantly related to higher recurrence rate (37.5% vs. 12.7%, P < .05) and to lower 5-year patient survival (38% vs. 78%, P < .005%) in the preoperative analysis, but not in the postoperative one. The alfa-fetoprotein level of more than 30 ng/dL and the preoperative tumor volume of more than 28 cm3 predicted HCC recurrences in the univariate and mutivariate analysis (P < .005 and P < .05, respectively). The ROC curve showed a linear correlation between preoperative tumor volume and HCC recurrence. Milan criteria significantly reduced tumor recurrences after liver transplantation, improving long-term survival. In conclusion, the efficacy of tumor selection criteria must be analyzed with the use of preoperative data, to avoid bias of the postoperative evaluation. Tumor volume and alfa-fetoprotein level may improve the selection of patients. Copyright © 2004 by the American Association for the Study of Liver Diseases
Особенности использования кросс-культурного подхода в менеджменте на примере компании "Газпром нефть"
Recovery of distal coronary flow reserve in LAD and LCx after Y-Graft intervention assessed by transthoracic echocardiography
<p>Abstract</p> <p>Background</p> <p>Y- graft (Y-G) is a graft formed by the Left Internal Mammary Artery (LIMA) connected to the Left Anterior Descending Artery (LAD) and by a free Right Internal Mammary Artery (RIMA) connected to LIMA and to a Marginal artery of Left Circumflex Artery (LCx). Aim of the work was to study the flow of this graft during a six months follow-up to assess whether the graft was able to meet the request of all the left coronary circulation, and to assess whether it could be done by evaluation of coronary flow reserve (CFR).</p> <p>Methods</p> <p>In 13 consecutive patients submitted to Y-G (13 men), CFR was measured in distal LAD and in distal LCx from 1 week after , every two months, up to six months after operation (a total of 8 tests for each patient) by means of transthoracic echocardiography (TTE) and Adenosine infusion (140 mcg/kg/min for 3-6 min). A Sequoia 256, Acuson-Siemens, was used. Contrast was used when necessary (Levovist 300 mg/ml solution at a rate of 0,5-1 ml/min). Max coronary flow diastolic velocity post-/pre-test ≥2 was considered normal CFR.</p> <p>Results</p> <p>Coronary arteriography revealed patency of both branches of Y-G after six months. Accuracy of TTE was 100% for LAD and 85% for LCx. Feasibility was 100% for LAD and 85% for LCx. CFR improved from baseline in LAD (2.21 ± 0.5 to 2.6 ± 0.5, p = 0.03) and in LCx (1.7 ± 1 to 2.12 ± 1, p = 0.05). CFR was under normal at baseline in 30% of patients <it>vs </it>8% after six months in LAD (p = 0.027), and in 69% of patients <it>vs </it>30% after six months in LCx (p = 0.066).</p> <p>Conclusion</p> <p>CFR in Y-G is sometimes reduced in both left territories postoperatively but it improves at six months follow-up. A follow-up can be done non-invasively by TTE and CFR evaluation.</p
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