Robert D. Duval

Frequency of oral estrogen replacement therapy in women with normal and abnormal exercise electrocardiograms and normal coronary arteries by angiogram

Abstract The specificity of the exercise electrocardiogram has been reported to be lower in women than in men. 1 Using different standards, other investigators have reported no difference. 2 Nevertheless, there exists a relative consensus in the practicing medical community that a positive exercise electrocardiogram is of inherently less value in women than in men. Although one cannot discount the role that a lower prevalence of coronary artery disease in women 3 may play in this false-positive predisposition (i.e., reduced positive predictive accuracy), several authorities have speculated on a possible role for estrogen as a direct contributor to the false-positive exercise electrocardiogram in women (i.e., reduced specificity). 1,4 This study reviews our experience with exercise electrocardiography in women without atherosclerotic coronary artery disease by angiogram and assesses whether estrogen was associated with (false)-positive ST-segment changes.

Is morality policy different? : institutional explanations for postwar western europe

Although there has been increasing recognition that morality policy in Western democracies is a distinctive field of study, many analyses are relatively narrow in issues and jurisdictions. This contribution examines broad empirical patterns for five morality policy issues across 18 West European democracies since World War II. The issues analysed are abortion, capital punishment, euthanasia, assisted reproductive technology (ART, including stem cell research) and same-sex marriage. Which of two prominent institutional theories of morality policy, policy type and two worlds, help explain morality policy processes? The results indicate that morality policy processes do differ from the usual ones of parliamentary government, and that important differences are captured by the religious/secular division of party systems, depending on which countries are considered for each category.

Accuracy of ST/heart rate index in the diagnosis of coronary artery disease

The accuracy of ST/heart rate (ST HR) index was evaluated in patients presenting for exercise electrocardiography with suspected coronary disease. In all, 420 patients (235 men and 185 women) with normal electrocardiograms at rest underwent exercise testing, followed within 3 months by coronary angiography. The sensitivity and specificity for standard ST criteria (greater than or equal to 1 mm horizontal or downsloping depression) were 48% (78 of 162) and 81% (208 of 258), respectively. An ST HR-index threshold of 1.86 microV/beta/min had the exact same specificity with a sensitivity of 44% (71 of 162; p = not significant). Consideration of greater than or equal to 1.5 mm upsloping depression had no significant impact on the aforementioned results. Using multivariate logistic regression analysis, age, sex, symptoms, cigarette smoking, diabetes mellitus, qualitative ST slope, rate-pressure product, METs achieved and exercise angina were evaluated with and without ST HR index and ST depression. According to this analysis, age, sex, symptoms and ST slope were good predictors of presence or absence of disease. Neither ST HR index nor ST depression had significance in the multivariate analysis. However, when a separate analysis was performed in men and women, the 2 quantitative ST variables showed significance in men, but not in women. Comparisons of discriminative accuracy using receiver-operating characteristic curves demonstrated differences between men and women, but no difference between ST HR index and ST depression. Therefore, concerning questions of coronary disease diagnosis, consideration of ST HR index was not better than standard ST criteria, and added nothing to multivariate analysis of other available variables.

Incremental evaluation of exercise capacity as an independent predictor of coronary artery disease presence and extent

To determine the independent incremental value of exercise capacity (METS) concerning the presence and extent of coronary artery disease, we analyzed data from 800 patients with suspected coronary disease who underwent both exercise testing and coronary angiography. We performed logistic regression analysis of clinical and exercise test data with an incremental design to mimic the usual flow of data acquisition. Separate analyses were performed concerning coronary disease presence (> or = 1 vessel with a > or = 50% lesion) and extent (three-vessel/left main disease). Diagnostic accuracy was determined by calculating receiver operating characteristic (ROC) curve areas. When considered alone, METS was a significant predictor of both presence and extent of disease. Multivariate analysis revealed that METS was an independent predictor of disease extent but not presence. However, comparison of ROC curve areas failed to show any loss of accuracy when METS was removed from the coronary disease extent analysis. Despite the strong univariate relationship between exercise capacity and coronary disease presence and extent and the independence of exercise capacity as a predictor of coronary disease extent, the lack of an additional incremental accuracy attributed to its consideration virtually cancels its value as a diagnostic variable for assessing both coronary disease presence and extent.

Reconsidering the Aggregate Relationship between Size, Economic Development, and Some Types of Foreign Policy Behavior

In a reexamination of the relationship between the size of a nation-state and its foreign policy behavior, two sets of hypotheses which relate size to verbal/nonverbal and conflictual/cooperative dimensions of foreign policy activity are retested, after a discussion of previous problems of definitions, data, and method. Contrary to the findings of East (1973), the proportion of verbal or nonverbal behavior is found to be unrelated to size. The conflict/cooperation hypothesis is also not supported; however, a weak negative relationship between economic development and the proportion of conflictual activity is observed. In conclusion, the utility of the large state/small state dichotomy in studying the behavior of small states is called into question.

A Hierarchical Algorithm for Clustering Extremist Web Pages

Extremist political movements have proliferated on the web in recent years due to the advent of minimal publication costs coupled with near universal access, resulting in what appears to be an abundance of groups that hover on the fringe of many socially divisive issues. Whether white-supremacist, neo- Nazi, anti-abortion, black separatist, radical Christian, animal rights, or violent environmentalists, all have found a home (and voice) on the Web. These groups form social networks whose ties are predicated primarily on shared political goals. Little is known about these groups, their interconnections, their animosities, and most importantly, their growth and development and studies such as the Dark Web Project, while considering domestic extremists, have focused primarily on international terrorist groups. Yet here in the US, there has been a complex social dynamic unfolding as well. While left-wing radicalism declined throughout the 80s and 90s, right wing hate groups began to flourish. Today, the web offers a place for any brand of extremism, but little is understood about their current growth and development. While there is much to gain from in-depth studies of the content provided by these sites, there is also a surprising amount of information contained in their online network structure as manifested in links between and among these web sites. Our research follows the idea that much can be known about you by the company you keep. In this paper, we propose an approach to measure the intrinsic relationships (i.e., similarities) of a set of extremist web pages. In this model, the web presence of a group is thought of as a node in a social network and the links between these pages are the ties between groups. This approach takes the bi-directional hyperlink structure of web pages and, based on similarity scores, applies an effective multi-membership clustering algorithm known as the quasi clique merger method to cluster these web pages using a derived hierarchical tree. The experimental results show that this new similarity measurement and hierarchical clustering algorithm gives an improvement over traditional link based clustering methods.

Diagnostic accuracy of heart rate-adjusted ST segments compared with standard ST-segment criteria

We compared the accuracy of ST segment/heart rate (ST/HR) index with that of standard criteria (> or = 0.1 mV horizontal/downsloping ST depression 80 ms after the J point) in 121 patients who had undergone angiography (49 with > or = 1 lesion with > or = 50% stenosis) and 50 clinically normal subjects. All exercise tests used the Cornell protocol and computer measurements of maximal ST depression 80 ms after the J point. Thresholds with equal specificity to standard criteria were determined for ST/HR index using each of the 2 normal groups (those who were normal by angiography and those who were clinically normal). In using only patients who underwent angiography, we found that the ST/HR index had a sensitivity that was not significantly greater than that of standard criteria (standard criteria 51%, ST/HR index 59%; p = 0.21). However, the receiver-operating characteristic curve area increased from 64 +/- 4 to 68 +/- 4 (p < 0.02). When clinically normal subjects were used instead of patients without angiographic disease, there was a clearly discernible improvement in sensitivity of ST/HR index over standard criteria (standard criteria 51%, ST/HR index 69%; p < 0.05). The associated curve areas were 69 +/- 4 and 79 +/- 3 (p < 0.001). Therefore, accuracy of the ST/HR index was marginally better than standard criteria only in patients who underwent angiography. When clinically normal subjects were used, the accuracy of the ST/HR index was definitely better than standard criteria. We conclude that the demonstration of improved accuracy of the ST/HR index depends on the population being tested.

Comparison of logistic regression and Bayesian-based algorithms to estimate posttest probability in patients with suspected coronary artery disease undergoing exercise ECG.

Two multivariate methods, a logistic regression-derived algorithm and a Bayesian independence-assuming method (CADENZA), were compared concerning their abilities to estimate posttest probability of coronary disease in patients with suspected coronary disease. All patients underwent exercise testing within 3 months prior to coronary angiography. Coronary disease was defined as the presence of one or more vessels with greater than or equal to 50% luminal diameter narrowing. A group of 300 patients (disease prevalence = 37%) was used to derive the algorithm. Another group of 950 patients was used to validate the algorithm and compare it to CADENZA. Seven variables (age, sex, symptoms, diabetes, mm ST depression, ST slope, and peak heart rate) were used to generate posttest probabilities for each method. The receiver operating characteristic curve area for the logistic regression method (0.81 +/- 0.01) was significantly higher than CADENZA (0.75 +/- 0.01; p less than 0.05). There was, however, no difference in the calibration of the two methods. When given equivalent variable information, the logistic regression algorithm had better discrimination than CADENZA for estimating the probability of coronary disease following exercise electrocardiography.

Hidden Policies and Hypothesis Tests: The Implications of Type II Errors for Environmental Regulation

In an examination of the federal hazardous waste regulations, an analysis of the importance of Type II statistical errors is undertaken. A method for approximating the power of the test is developed, and the EPA policy is examined under selected situations. Additionally a Monte Carlo simulation is provided which compares the efficacy of the EPA required t-test with the Wilcoxon rank sum test. The paper offers a number of conclusions about the appropriateness of the EPA test under selected circumstances. It also concludes that by specifying a sampling scheme without benefit of direct discussion of Type II errors, policy decisions may lie hidden within the statistical test.

The built environment, maintenance of the public sphere and connections to others and to place: an examination of 10 international cities

Using surveys collected from 10 major metropolitan cities across the world, this article examines the factors that affect the extent to which people feel connected to others who live in their neighborhood and feel proud and satisfied with life in their cities. The cities included in the analysis are: New York, London, Paris, Stockholm, Toronto, Milan, Berlin, Seoul, Beijing and Tokyo. We find that certain aspects of the built environment, the conditions of the public sphere, and the extent of positive social networks in the city are critically important for understanding residents’ connections to each other and to their cities. Our findings provide insights for policy makers and planners concerned with making cities viable and livable.