Variational perturbation theory for dynamic polarizabilities and dispersion coefficients.

An efficient method based on the variational perturbation theory (VPT) is proposed to conveniently calculate the atomic real- and imaginary-frequency dynamic polarizabilities and the interatomic dispersion coefficients. The developed method holds the great advantage that only the system ground state wave function and corresponding radial mean values are needed. Verification of the VPT method on one- and two-electron atoms indicates that the present approximation shows good agreement with calculations based on the sophisticated sum-over-states method. We apply the VPT method to examine the approximate Z-scaling laws of polarizabilities and dispersion coefficients in the He isoelectronic sequence, and to investigate the plasma screening effect on these quantities for embedded atoms. Our calculation demonstrates very well that the VPT method is capable of producing reasonably accurate static and dynamic polarizabilities as well as two- and three-atom dispersion coefficients for plasma-embedded atoms in a wide range of screening parameters.

Psychological variables underlying political orientations in an old and a new democracy: A comparative study between Sweden and Latvia.

This study examines in detail the psychological variables underlying ideological political orientation, and structure and contents of this orientation, in Sweden and Latvia. Individual political orientation is conceptualized on two dimensions: acceptance vs. rejection of social change and acceptance vs. rejection of inequality. Swedish (N = 320) and Latvian (N = 264) participants completed measures of political orientation, Social Dominance Orientation (SDO), Right Wing Authoritarianism (RWA), self vs. other orientation, tolerance for ambiguity, humanism and normativism, core political values, system justification, as well as moral foundations questionnaire and portrait values questionnaire. The results showed that the relation among the measured variables was similar in both samples. Swedish participants showed stronger endorsement of egalitarian attitudes and social values, whereas we found more self-enhancing and socially conservative values and attitudes among the Latvian participants.

Coronary risk estimates and decisions on lipid-lowering treatment in primary prevention: comparison between general practitioners, internists, and cardiologists.

BACKGROUND: Quantitative assessment of an individual's absolute cardiovascular risk is essential for primary prevention. Although risk-scoring tools have been developed for this task, risk estimates are usually made subjectively. We investigated whether general practitioners (GPs), internists and cardiologists differ in their quantitative estimates of cardiovascular risk and their recommendations about lipid-lowering treatment for the same set of patients. METHODS: Mail survey. Nine written clinical vignettes, four rated high-risk and five rated low-risk according to the Framingham equation, were mailed to 90 randomly selected GPs and to the same number of internists and cardiologists in Sicily. The doctors were then asked to estimate the 10-year coronary risk in each case and to decide whether they would recommend a lipid-lowering treatment. RESULTS: In the majority of the nine cases, the cardiologists' risk estimates were significantly lower than those of the other two groups. A higher proportion of internists (mean value 0.68) decided to start treatment than GPs (0.54) or cardiologists (0.57). In all three groups, the doctors' willingness to begin treatment was over 90% when their risk estimate was above 20%, and less than 50% when it fell below this level. Internists were more prone to treat than the other two groups even when their patients' estimated risk was below 20%. CONCLUSION: When presented with the same set of clinical cases, GPs, internists and cardiologists make different quantitative risk estimates and come to different conclusions about the need for lipid-lowering treatment. This may result in over- or under-prescription of lipid-lowering drugs and inconsistencies in the care provided by different categories of doctors.

Improving fast and frugal modeling in relation to regression analysis: test of 3 models for medical decision making.

BACKGROUND: Data from 2 previous studies were reanalyzed, one on judgments regarding drug treatment of hyperlipidemia and the other on diagnosing heart failure. The original MH model and the extended MH model were compared with logistic regression (LR) in terms of fit to actual judgments, number of cues, and the extent to which the cues were consistent with clinical guidelines. RESULTS: There was a slightly better fit with LR compared with MH. The extended MH model gave a significantly better fit than the original MH model in the drug treatment task. In the diagnostic task, the number of cues was significantly lower in the MH models compared to LR, whereas in the therapeutic task, LR could be less or more frugal than the matching heuristic models depending on the significance level chosen for inclusion of cues. For the original MH model, but not for the extended MH model or LR, the most important cues in the drug treatment task were often used in a direction contrary to treatment guidelines. CONCLUSIONS: The extended MH model represents an improvement in that prevalence of cue values is adequately taken into account, which in turn may result in better fit and in better agreement with medical guidelines in the evaluation of cues.

Differentiating explanations of attitude-consistent behavior: the role of perspectives and mode of perspective taking.

We examined whether participants could differentiate between explanations of attitude-consistent behavior related to EU membership given from two perspectives (EU supporter and EU opponent) by means of three perspective taking modes (the explainer's own perspective, imagined in-group members' perspective, and imagined out-group members' perspective). Participants were presented with explanations provided from different perspectives and perspective taking modes, and they were asked to judge the extent to which they agreed with each explanation, to guess the attitude of the provider of each explanation, and to rate the quality of each explanation in various respects. Participants could not differentiate between explanations given by in-group members and out-group members who imagined the same perspective. They responded more favorably to explanations given from own perspective than from the imagined perspectives. The results suggest that there exists a shared understanding about how both sides should explain attitude-consistent behavior, but this understanding is measurably different from the actual explanations.

General practitioners' reasoning when considering the diagnosis heart failure: a think-aloud study.

BACKGROUND: Diagnosing chronic heart failure is difficult, especially in mild cases or early in the course of the disease, and guidelines are not easily implemented in everyday practice. The aim of this study was to investigate general practitioners' diagnostic reasoning about patients with suspected chronic heart failure in comparison with recommendations in European guidelines. METHODS: Think-aloud technique was used. Fifteen general practitioners reasoned about six case vignettes, representing authentic patients with suspected chronic heart failure. Information about each case was added successively in five steps. The general practitioners said their thoughts aloud while reasoning about the probability of the patient having chronic heart failure, and tried to decide about the diagnosis. Arguments for and against chronic heart failure were analysed and compared to recommendations in guidelines. RESULTS: Information about ejection fraction was the most frequent diagnostic argument, followed by information about cardiac enlargement or pulmonary congestion on chest X-ray. However, in a third of the judgement situations, no information about echocardiography was utilized in the general practitioners' diagnostic reasoning. Only three of the 15 doctors used information about a normal electrocardiography as an argument against chronic heart failure. Information about other cardio-vascular diseases was frequently used as a diagnostic argument. CONCLUSIONS: The clinical information was not utilized to the extent recommended in guidelines. Some implications of our study are that 1) general practitioners need more information about how to utilize echocardiography when diagnosing chronic heart failure, 2) guidelines ought to give more importance to information about other cardio-vascular diseases in the diagnostic reasoning, and 3) guidelines ought to treat the topic of diastolic heart failure in a clearer way.

GPs' decisions on drug treatment for patients with high cholesterol values: a think-aloud study.

BACKGROUND: The purpose was to examine how General Practitioners (GPs) use clinical information and rules from guidelines in their decisions on drug treatment for high cholesterol values. METHODS: Twenty GPs were presented with six case vignettes and were instructed to think aloud while successively more information about a case was presented, and finally to decide if a drug should be prescribed or not. The statements were coded for the clinical information to which they referred and for favouring or not favouring prescription. RESULTS: The evaluation of clinical information was compatible with decision-making as a search for reasons or arguments. Lifestyle-related information like smoking and overweight seemed to be evaluated from different perspectives. A patient's smoking favoured treatment for some GPs and disfavoured treatment for others. CONCLUSIONS: The method promised to be useful for understanding why doctors differ in their decisions on the same patient descriptions and why rules from the guidelines are not followed strictly.

Differentiating in-group favoritism from shared reality in intergroup perception.

Two basic factors influence mutual ratings of social groups: in-group favoritism (related to the evaluative aspects of a rating) and the perception of shared reality (related to the descriptive aspects). In two studies, we examine the usefulness of Peabody's (1968) method of separating evaluative and descriptive aspects of rating in intergroup judgments. In Study 1, Latvian and Russian students made different evaluations of both groups, but the same groups agreed on the descriptive ratings. In Study 2, male and female psychology students rated each other from own, in-group, and out-group perspectives. The participants did not show any in-group favoritism in their own ratings, but they expected their fellow students to be in-group biased. The participants agreed on the descriptive ratings of both groups. The results demonstrate that shared reality influences intergroup ratings, despite differences in evaluations.

Engaging in activities involving information technology: dimensions, modes, and flow.

An engagement mode involves a subject (e.g., a user of information technology, or IT) who is engaged in an activity with an object in a certain manner (the mode). The purpose of this study is to develop a general model of engagement modes that may be used for understanding how IT-related activities are shaped by properties of the user and the IT object. A questionnaire involving items on IT engagement and the experience of flow was administered to 300 participants. The results supported an engagement mode (EM) model involving 5 different engagement modes (enjoying/acceptance, ambition/curiosity, avoidance/hesitation, frustration/ anxiety, and efficiency/productivity) characterized on 3 dimensions (evaluation of object, locus of control between subject and object, and intrinsic or extrinsic focus of motivation). The flow experience follows from a balance between enjoying/ acceptance and efficiency/productivity propelled by ambition/curiosity. The EM model could provide a platform for considering how IT users, IT applications, and IT environments should work together to yield both enjoyment and efficiency. Actual or potential applications of this research include designing IT training programs on different levels of specificity.

The role of guidelines and the patient's life-style in GPs' management of hypercholesterolaemia.

BACKGROUND: Recent Swedish and joint European guidelines on hyperlipidaemia stress the high coronary risk for patients with already established arterio-sclerotic disease (secondary prevention) or diabetes. For the remaining group, calculation of the ten-year risk for coronary events using the Framingham equation is suggested. There is evidence that use of and adherence to guidelines is incomplete and that tools for risk estimations are seldom used. Intuitive risk estimates are difficult and systematically biased. The purpose of the study was to examine how GPs use knowledge of guidelines in their decisions to recommend or not recommend a cholesterol-lowering drug and the reasons for their decisions. METHODS: Twenty GPs were exposed to six case vignettes presented on a computer. In the course of six screens, successively more information was added to the case. The doctors were instructed to think aloud while processing the cases (Think-Aloud Protocols) and finally to decide for or against drug treatment. After the six cases they were asked to describe how they usually reason when they meet patients with high cholesterol values (Free-Report Protocols). The two sets of protocols were coded for cause-effect relations that were supposed to reflect the doctors' knowledge of guidelines. The Think-Aloud Protocols were also searched for reasons for the decisions to prescribe or not to prescribe. RESULTS: According to the protocols, the GPs were well aware of the importance of previous coronary heart disease and diabetes in their decisions. On the other hand, only a few doctors mentioned other arterio-sclerotic diseases like stroke and peripheral artery disease as variables affecting their decisions. There were several instances when the doctors' decisions apparently deviated from their knowledge of the guidelines. The arguments for the decisions in these cases often concerned aspects of the patient's life-style like smoking or overweight- either as risk-increasing factors or as alternative strategies for intervention. CONCLUSIONS: Coding verbal protocols for knowledge and for decision arguments seems to be a valuable tool for increasing our understanding of how guidelines are used in the on treatment of hypercholesterolaemia. By analysing arguments for treatment decisions it was often possible to understand why departures from the guidelines were made. While the need for decision support is obvious, the current guidelines may be too simple in some respects.