Induction of First-Order Decision Lists: Results on Learning the Past Tense of English Verbs

This paper presents a method for inducing logic programs from examples that learns a new class of concepts called first-order decision lists, defined as ordered lists of clauses each ending in a cut. The method, called FOIDL, is based on FOIL (Quinlan, 1990) but employs intensional background knowledge and avoids the need for explicit negative examples. It is particularly useful for problems that involve rules with specific exceptions, such as learning the past-tense of English verbs, a task widely studied in the context of the symbolic/connectionist debate. FOIDL is able to learn concise, accurate programs for this problem from significantly fewer examples than previous methods (both connectionist and symbolic).Comment: See http://www.jair.org/ for any accompanying file

Prospective relationships between body weight and physical activity: an observational analysis from the NAVIGATOR study

Objectives: While bidirectional relationships exist between body weight and physical activity, direction of causality remains uncertain and previous studies have been limited by self-reported activity or weight and small sample size. We investigated the prospective relationships between weight and physical activity. Design: Observational analysis of data from the Nateglinide And Valsartan in Impaired Glucose Tolerance Outcomes Research (NAVIGATOR) study, a double-blinded randomised clinical trial of nateglinide and valsartan, respectively. Setting Multinational study of 9306 participants. Participants: Participants with biochemically confirmed impaired glucose tolerance had annual measurements of both weight and step count using research grade pedometers, worn for 7 days consecutively. Along with randomisation to valsartan or placebo plus nateglinide or placebo, participants took part in a lifestyle modification programme. Outcome measures: Longitudinal regression using weight as response value and physical activity as predictor value was conducted, adjusted for baseline covariates. Analysis was then repeated with physical activity as response value and weight as predictor value. Only participants with a response value preceded by at least three annual response values were included. Results: Adequate data were available for 2811 (30%) of NAVIGATOR participants. Previous weight (χ2=16.8; p<0.0001), but not change in weight (χ2=0.1; p=0.71) was inversely associated with subsequent step count, indicating lower subsequent levels of physical activity in heavier individuals. Change in step count (χ2=5.9; p=0.02) but not previous step count (χ2=0.9; p=0.34) was inversely associated with subsequent weight. However, in the context of trajectories already established for weight (χ2 for previous weight measurements 747.3; p<0.0001) and physical activity (χ2 for previous step count 432.6; p<0.0001), these effects were of limited clinical importance. Conclusions: While a prospective bidirectional relationship was observed between weight and physical activity, the magnitude of any effect was very small in the context of natural trajectories already established for these variables

738–2 The Evolution of Therapy for Single Vessel Disease: A Treatment Comparison of Medicine, Angioplasty and Left Internal Mammary Artery Graft for Proximal Left Anterior Descending Disease

Saphenous vein bypass grafting for single vessel disease offers no survival or symptom relief advantage compared to medical therapy. Recent evidence suggests the use of the internal mammary artery or PTCA may be more beneficial than medicine. To examine the outcome of these treatment strategies, a retrospective analysis of prospectively collected data on 23,018 consecutive patients undergoing cardiac catheterization between April 1986 and February 1994 was performed. Of the 6,432 patients with single vessel disease, 1,222 had a proximal left anterior descending (LAD) stenosis>74% and no prior PTCA or CABG. A total of 289 were managed medically, 760 underwent PTCA, and 172 received a left internal mammary artery (LIMA) graft.Baseline demographic data and risk factor profiles were similar except for a higher incidence of diabetes (19 vs 15 vs 11%), history of MI (72 vs 58 vs 48%) CHF (18 vs 7 vs 8%), and total occlusions (44 vs 17 vs 7%) and lower incidence of unstable angina (40 vs 61 vs 64%) in the medical group as compared to PTCA and LIMA graft, respectively.Kaplan-Meier 6-year estimates:EventsMedicinePTCALIMAP-value–unadjusted survival (%)7885910.001–adjusted survival (%)8486900.24–event-free survival (%)5443720.0001ConclusionThere is a trend towards improved long-term survival in proximal LAD disease with a strategy of revascularization, particularly the LIMA graft. Furthermore, event-free survival is significantly improved with the LIMA graft as compared to medical therapy or PTCA

THEMIS measurements of quasi‐static electric fields in the inner magnetosphere

We use 4 years of Time History of Events and Macroscale Interactions during Substorms (THEMIS) double‐probe measurements to offer, for the first time, a complete picture of the dawn‐dusk electric field covering all local times and radial distances in the inner magnetosphere based on in situ equatorial observations. This study is motivated by the results from the CRRES mission, which revealed a local maximum in the electric field developing near Earth during storm times, rather than the expected enhancement at higher L shells that is shielded near Earth as suggested by the Volland‐Stern model. The CRRES observations were limited to the duskside, while THEMIS provides complete local time coverage. We show strong agreement with the CRRES results on the duskside, with a local maximum near L = 4 for moderate levels of geomagnetic activity and evidence of strong electric fields inside L = 3 during the most active times. The extensive data set from THEMIS also confirms the day/night asymmetry on the duskside, where the enhancement is closest to Earth in the dusk‐midnight sector, and is farther away closer to noon. A similar, but smaller in magnitude, local maximum is observed on the dawnside near L = 4. The noon sector shows the smallest average electric fields, and for more active times, the enhancement develops near L = 7 rather than L = 4. We also investigate the impact of the uncertain boom‐shorting factor on the results and show that while the absolute magnitude of the electric field may be underestimated, the trends with geomagnetic activity remain intact.Key PointsWe show full local time coverage of the equatorial electric field from THEMISLocal maximum occurs near L = 4 during active times in dawn and dusk sectorsNo clear increased electric field with Kp near midnight at high LPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110619/1/jgra51411.pd

Abrupt closure: The CAVEAT I experience

Objectives.This study sought to assess the incidence and consequences of abrupt closure in a series of patients undergoing directional coronary atherectomy versus percutaneous coronary angioplasty.Background.Abrupt closure with coronary angioplasty has been associated with adverse outcome. The results from the Coronary Angioplasty Versus Excisional Atherectomy Trial (CAVEAT) I, a randomized trial of coronary angioplasty versus directional coronary atherectomy, were analyzed.Method.This multicenter trial enrolled 1,012 patients from 1991 to 1992. All records from patients with abrupt closure, which was coded as a discrete complication, were reviewed.Results.Abrupt closure occurred in 60 patients (5.9%) and was associated with a significantly longer hospital stay (median 8 vs. 3 days). Severe proximal target vessel tortuosity was more common in patients with abrupt closure (20.3% vs. 11.6%, p = 0.046), as was preexistent coronary artery thrombus (30.5% vs. 18.3%, p = 0.02). Abrupt closure was associated with a marked increase in subsequent complications (myocardial infarction 46.7% vs. 2.1%, emergency bypass surgery 383% vs. 0.32%, death 33% vs. 0%) and occurred more frequently in the directional coronary atherectomy group (8.0% vs. 3.8%, p = 0.005). In the coronary angioplasty group, the occlusion usually occurred at the target lesion (91%), presumably related to the effects of barotrauma. In the directional coronary atherectomy group, the site of the occlusion was the target lesion in only 58% (p = 0.045). The remaining occlusions related to problems with the technique (guide catheter or nose cone trauma), reflecting the fact that directional coronary atherectomy is a more complex procedure.Conclusions.Abrupt closure remains the principal determinant of adverse outcome after percutaneous procedures for the treatment of coronary artery disease. Although abrupt closure is more common with directional atherectomy than angioplasty, the sequelae are similar

790-2 Baseline Electrocardiogram Predicts 30-day Mortality Among 32,812 Patients with Acute Myocardial Infarction Treated with Thrombolysis

To determine the initial electrocardiographic variables predictive of survival among patients with acute myocardial infarction, we analyzed the baseline 12-lead ECGs in 32,812 patients enrolled into the GUSTO trial. All patients had≥0.1mV of ST segment elevation in at least one lead and received thrombolytic therapy. Those with LBBB or ventricular rhythm were excluded from analysis. Clinical follow-up was > 99.5% complete. 2218 (6.8%) patients died within 30 days of the initial ECG. Death within 30 days was more common in patients with RBBB (17%), LAFB (14%), and LPFB (17%), than in those with a normal conduction pattern (6%). Patients with ECG evidence of previous MI in a location distinct from the acute MI had a higher risk of death (9.8% vs. 5.9%) than those without prior infarction (p<0.0001). The variable having the greatest univariate predictive power for 30-day survival was the sum of the absolute ST-segment deviation in each lead (x2=341), as shown in the following mortality curve.Other ST segment variables that predicted 30-day survival were the sum of ST-segment elevation in each lead (x2=287). the maximum ST elevation in anyone lead (X2=257), and the number of leads with ST elevation (x2=250). When multivariate modeling was performed the sum of the absolute ST deviations, number of leads with ST elevation, prior ECG MI, RBBB, and LAFB each added independent prognostic information.We conclude that an ECG at the time of presentation contains substantial prognostic information which can be used to help stratify risk among thrombelytic-treated patients with acute myocardial infarction

Acute Decline in Renal Function, Inflammation, and Cardiovascular Risk after an Acute Coronary Syndrome

Background and objectives: Chronic kidney disease is associated with a higher risk of cardiovascular outcomes. The prognostic significance of worsening renal function has also been shown in various cohorts of cardiac disease; however, the predictors of worsening renal function and the contribution of inflammation remains to be established. Design, setting, participants, & measurements: Worsening renal function was defined as a 25% or more decrease in estimated GFR (eGFR) over a 1-mo period in patients after a non-ST or ST elevation acute coronary syndromes participating in the Aggrastat-to-Zocor Trial; this occurred in 5% of the 3795 participants. Results: A baseline C-reactive protein (CRP) in the fourth quartile was a significant predictor of developing worsening renal function (odds ratio, 2.48; 95% confidence interval, 1.49, 4.14). After adjusting for baseline CRP and eGFR, worsening renal function remained a strong multivariate predictor for the combined cardiovascular composite of CV death, recurrent myocardial infarction (MI), heart failure or stroke (hazard ratio, 1.6; 95% confidence interval, 1.1, 2.3). Conclusions: Patients with an early decline in renal function after an acute coronary syndrome are at a significant increased risk for recurrent cardiovascular events. CRP is an independent predictor for subsequent decline in renal function and reinforces the idea that inflammation may be related to the pathophysiology of progressive renal disease

Individual risk assessment for intracranial haemorrhage during thrombolytic therapy

Thrombolytic therapy improves outcome in patients with myocardial infarction but is associated with an increased risk of intracranial haemorrhage. For some patients, this risk may outweigh the potential benefits of thrombolytic treatment. Using data from other studies, we developed a model for the assessment of an individual's risk of intracranial haemorrhage during thrombolysis. Data were available from 150 patients with documented intracranial haemorrhage and 294 matched controls. 49 patients with intracranial haemorrhage and 122 controls had been treated with streptokinase, whereas 88 cases and 148 controls had received alteplase. By multivariate analysis, four factors were identified as independent predictors of intracranial haemorrhage; age over 65 years (odds ratio 2·2 [95% Cl 1·4–3·5]), body weight below 70 kg (2·1 [1·3–3·2]), hypertension on hospital admission (2·0 [1·2–3·2]), and administration of alteplase (1·6 [1·0–2·5]). If the overall incidence of intracranial haemorrhage is assumed to be 0·75%, patients without risk factors who receive streptokinase have a 0·26% probability of intracranial haemorrhage. The risk is 0·96%, 1·32%, and 2·17% in patients with one, two, or three risk factors, respectively. We present a model for individual risk assessment that can be used easily in clinical practice

Transcript of The Dory Derby Accident

This story is an excerpt from a longer interview that was collected as part of the Launching through the Surf: The Dory Fleet of Pacific City project. In this story, Don Grotjohn recounts an accident that occurred during a Dory Derby competition

Relation between dose of loop diuretics and outcomes in a heart failure population: Results of the ESCAPE Trial

We examined the relation of maximal in-hospital diuretic dose to weight loss, changes in renal function, and mortality in hospitalised heart failure (HF) patients