Effects of a preventive cardiology curriculum on behavioral cardiovascular risk factors and knowledge of medical students

We evaluated a Preventive Cardiology Academic Award (PCAA) program designed to integrate preventive cardiology concepts into the medical school curriculum. Diet, preventive cardiology knowledge, preventive cardiology attitudes, exercise behavior, and body mass index were compared at entrance to medical school and during the graduation year. Complete data were available on 94 students (65 men and 29 women). Similar data from students who graduated in 1987, prior to the introduction of the PCAA curriculum, served as a control. Women showed a significant enhancement in attitude towards cardiovascular disease (CVD) prevention, while both men and women significantly increased their knowledge about CVD prevention. The frequency of planned physical activity decreased significantly in both sexes and men showed a significant increase in body mass index. Men significantly reduced total calories, percent of calories from fat and saturated fat and dietary cholesterol and increased fiber intake. In women, the only significant reduction was in total calories. In comparison to the control class that did not have the program, men receiving the PCAA curriculum reduced dietary cholesterol, dietary fat, saturated fat and monounsaturated fat. Changes in these dietary parameters were nonsignificant for women in comparison to the control class women. Additional analyses showed no systematic secular trends in dietary or other variables in classes entering from 1986 to 1990. We conclude that the PCAA curriculum changes have favorably affected the preventive cardiology knowledge, attitudes and diet of medical students.     

Framing Space and Time in the City: Urban Policy and the Politics of Spatial and Temporal Scale

Abstract: This article seeks to analyze urban politics through the lens of the social constructionist approach to scale. This approach views scale not as a set of pre‐given, natural, and immutable levels upon which social life occurs. Rather, it regards scale as a fluid context for and product of power relations in society. The article argues that urban politics is frequently characterized by political strategies that frame reality in terms of scale. Agents of the state, capital, and civil society all engage in the politics around competing scalar framings. As a result, the politics of scale has important but contingent material consequences. The article illustrates these points through a case study of the politics that surrounded the development of a new neighborhood planning initiative in Austin, Texas in the late 1990s. Based on this case study, the article also argues that while geographers studying the politics of scale tend to explain it solely in terms of spatial scale, scalar politics in the urban context frequently combines framings of spatial and temporal scale. This simultaneous framing of space and time in the city has important, if sometimes unpredictable, implications for policy and politics.     

Carotid artery balloon test occlusion: combined clinical evaluation and xenon-enhanced computed tomographic cerebral blood flow evaluation without patient transfer or balloon reinflation: technical note

OBJECTIVE: Clinical evaluation was combined with xenon-enhanced computed tomographic (CT) cerebral blood flow (CBF) evaluation during carotid artery balloon test occlusion (BTO), without patient transfer from the angiography suite to the CT scanner or balloon reinflation. TECHNIQUE: Thirteen patients underwent carotid artery BTO. Placement of temporary occlusion balloons was performed with patients positioned on the CT scanner table. If neurological testing revealed no changes within 10 minutes after balloon inflation, patients were positioned within the CT scanner gantry for xenon-enhanced CT CBF evaluation. CBF evaluations were begun 12 to 15 minutes after balloon inflation and required 8 minutes for completion. After completion of CBF evaluation, neurological testing continued during 30 minutes of arterial occlusion. RESULTS: One patient did not tolerate BTO, with the development of reversible hemiparesis. Reliable CBF data were not obtained because of patient motion in one case. Eleven patients clinically tolerated BTO and completed CBF evaluation. For five patients, xenon-enhanced CT scanning revealed no regions with CBF of less than 30 ml/100 g/min. For four patients, xenon-enhanced CT scanning revealed small regions with CBF of less than 30 ml/100 g/min within the anterior frontal lobe on the occluded side. For two patients, ipsilateral CBF decreased dramatically during BTO, with CBF in many regions of less than 30 ml/100 g/min and in some of less than 20 ml/100 g/min. CONCLUSION: Xenon-enhanced CT CBF evaluation can be combined with clinical testing during BTO without patient transfer, balloon reinflation, or increases in the duration of the procedure. We recognize that the value of CBF evaluation during BTO remains to be proven; our technique does, however, eliminate abbreviated clinical neurological evaluation, patient transfer, and balloon reinflation, which were previously associated with the use of xenon-enhanced CT CBF evaluation during carotid artery BTO.     

Robust variable selection using least angle regression and elemental set sampling

The problem of selecting variables or features in a regression model in the presence of both additive (vertical) and leverage outliers is addressed. Since variable selection and the detection of anomalous data are not separable problems, the focus is on methods that select variables and outliers simultaneously. For selection, the fast forward selection algorithm, least angle regression (LARS), is used, but it is not robust. To achieve robustness to additive outliers, a dummy variable identity matrix is appended to the design matrix allowing both real variables and additive outliers to be in the selection set. For leverage outliers, these selection methods are used on samples of elemental sets in a manner similar to that used in high breakdown robust estimation. These results are compared to several other selection methods of varying computational complexity and robustness. The extension of these methods to situations where the number of variables exceeds the number of observations is discussed.     

On the utility of experiential cross-training for team decision-making under time stress

This study investigated the effectiveness of experiential cross-training in a team context for team decision-making under time stress in a simulated naval surveillance task. It was hypothesized that teams whose members explicitly experience all team positions will perform better under time pressure due to a better shared Team Interaction Model (Cannon-Bowers et al. 1993). In addition, it was posited that experiential cross-training would reduce the negative effect of member reconfiguration that can occur in certain military situations. Three groups of teams participated in this study (cross-trained, reconfigured and control). The experiment involved three team training sessions, followed by three time-stressed exercise sessions. During training, one group of teams was cross-trained (CT) by asking each member to perform an entire session at each of the three team positions. Member reconfiguration (where each member was shifted to another's position) was unexpectedly introduced at the first of the exercise sessions for the CT group and for another group (reconfigured) that had not been cross-trained. A third (control) group was neither cross-trained nor reconfigured. During training, the performance of non-CT teams improved more quickly than that of CT teams. During the exercise, the CT group did not achieve the level of performance of the control teams. The immediate effect of team member reconfiguration was to degrade performance significantly for the non-CT teams, but not for CT teams. The findings are discussed in terms of the multiple mental models' view of team performance (Cannon-Bowers et al. 1993) and the authors discuss the relative utility of cross-training when overall training time is fixed.     

The ultrastructure of benign pigmented naevi and melanocarcinomas in man

Nine benign pigmented naevi and 16 melanocarcinomas (malignant melanomas) were studied by light and transmission electron microscopy and the fine structure of benign and malignant melanocytes is described. It was found that malignant melanocytes generally exhibit a range of abnormalities of structure of nuclei and cytoplasmic organelles which distinguish them clearly from their benign counterparts. Of the abnormalities, those affecting the specific organelle of the melanocyte, the melanosome, were the most constantly present. No firm evidence was found for the existence of two types of melanosome or two types of melanocarcinoma. Although electron microscopy is capable of showing in great detail within individual melanocytes many changes which are clearly associated with malignancy, the technique does not appear to offer significant advantages over light microscopy in determining the diagnosis and prognosis in this group of conditions.     

Indirect Determination of Microelectrode Geometry

Measurement of the electrical properties of living cell membranes often involves electrolyte filled glass capillary microelectrodes, the properties of which enter into the interpretation of the measurements. Since the tips of the electrodes are beyond the resolving power of the light microscope, we present here indirect methods for the determination of the tip geometry based on resistance measurements. A model consisting of a 2-parameter family of geometric shapes is selected to agree with observed resistances over a range of hydrostatic pressure heads and fluid conductivities. For a specific electrode the two defining parameters are evaluated from the resistances of the electrode when immersed successively in pools of two different conductivities.