Extensions quadratiques 2-birationnelles de corps totalement réels

We characterize 2-birational CM-extensions of totally real number fields in terms of tame ramification. This result completes in this case a previous work on pro-l-extensions over 2-rational number fields

My Action, My Self: Recognition of Self-Created but Visually Unfamiliar Dance-Like Actions From Point-Light Displays

Previous research has shown that motor experience of an action can facilitate the visual recognition of that action, even in the absence of visual experience. We conducted an experiment in which participants were presented point-light displays of dance-like actions that had been recorded with the same group of participants during a previous session. The stimuli had been produced with the participant in such a way that each participant experienced a subset of phrases only as observer, learnt two phrases from observation, and created one phrase while blindfolded. The clips presented in the recognition task showed movements that were either unfamiliar, only visually familiar, familiar from observational learning and execution, or self-created while blind-folded (and hence not visually familiar). Participants assigned all types of movements correctly to the respective categories, showing that all three ways of experiencing the movement (observed, learnt through observation and practice, and created blindfolded) resulted in an encoding that was adequate for recognition. Observed movements showed the lowest level of recognition accuracy, whereas the accuracy of assigning blindfolded self-created movements was on the same level as for unfamiliar and learnt movements. Self-recognition was modulated by action recognition, as participants were more likely to identify themselves as the actor in clips they had assigned to the category “created” than in clips they had assigned to the category “learnt,” supporting the idea of an influence of agency on self-recognition

EgoCor: an R package to fit exponential semi-variograms to model the local spatial correlation structure of health outcomes

As an alternative to using administrative areas for the evaluation of small-area health inequalities, Sauzet et al suggested to take an ego-centred approach and model the spatial correlation structure of health outcomes at individual level. Existing tools for the analysis of spatial data in R may appear too complex to non-specialists which may limit the use of the approach. We present the R package EgoCor which offers a user-friendly interface displaying in one function a range of graphics and tables of parameters to facilitate the decision making about which exponential parameters fit best either raw data or residuals. This function is based on the functions of the R package gstat. Moreover, we implemented a function providing the measure of uncertainty proposed by Dyck and Sauzet. With the R package EgoCor the modelling of spatial correlation structure of health outcomes with a measure of uncertainty is made available to non specialists.Comment: Keywords: R package, semi-variogram, exponential models, small-area health inequalitie

Bias in cohort-based comparisons of immigrants’ health outcomes between countries. A simulation study

Sauzet O, Razum O. Bias in cohort-based comparisons of immigrants’ health outcomes between countries. A simulation study. BMC Public Health. 2019;19(1): 913.Background Cohort-type data are increasingly used to compare health outcomes of immigrants between countries, e.g. to assess the effects of different national integration policies. In such international comparisons, small differences in cardiovascular diseases risk or mortality rates have been interpreted as showing effects of different policies. We conjecture that cohort-type data sets available for such comparisons might not provide unbiased relative risk estimates between countries because of differentials in migration patterns occurring before the cohorts are being observed. Method Two simulation studies were performed to assess whether comparisons are biased if there are differences in 1. the way migrants arrived in the host countries, i.e. in a wave or continuously; 2. the effects on health of exposure to the host country; or 3., patterns of return-migration before a cohort is recruited. In the first simulation cardiovascular disease was the outcome and immortality in the second. Bias was evaluated using a Cox regression model adjusted for age and other dependant variables. Results Comparing populations from wave vs. continuous migration may lead to bias only if the duration of stay has a dose-response effect (increase in simulated cardiovascular disease risk by 5% every 5 years vs. no risk: hazard-ratio 1.20(0.15); by 10% every 5 years: 1.47(0.14)). Differentials in return-migration patterns lead to bias in mortality rate ratios (MRR). The direction (under- or overestimation) and size of the bias depends on the model (MRR from 0.92(0.01) to 1.09(0.01)). Conclusion The order of magnitude of the effects interpreted as due to integration policies in the literature is the same as the bias in our simulations. Future studies need to take into account duration and relevance of exposure and return-migration to make valid inferences about the effects of integration policies on the health of immigrants

My Action, My Self: Recognition of Self-Created but Visually Unfamiliar Dance-Like Actions From Point-Light Displays

Bläsing B, Sauzet O. My Action, My Self: Recognition of Self-Created but Visually Unfamiliar Dance-Like Actions From Point-Light Displays. Frontiers in Psychology. 2018;9: 1909.Previous research has shown that motor experience of an action can facilitate the visual recognition of that action, even in the absence of visual experience. We conducted an experiment in which participants were presented point-light displays of dance-like actions that had been recorded with the same group of participants during a previous session. The stimuli had been produced with the participant in such a way that each participant experienced a subset of phrases only as observer, learnt two phrases from observation, and created one phrase while blindfolded. The clips presented in the recognition task showed movements that were either unfamiliar, only visually familiar, familiar from observational learning and execution, or self-created while blind-folded (and hence not visually familiar). Participants assigned all types of movements correctly to the respective categories, showing that all three ways of experiencing the movement (observed, learnt through observation and practice, and created blindfolded) resulted in an encoding that was adequate for recognition. Observed movements showed the lowest level of recognition accuracy, whereas the accuracy of assigning blindfolded self-created movements was on the same level as for unfamiliar and learnt movements. Self-recognition was modulated by action recognition, as participants were more likely to identify themselves as the actor in clips they had assigned to the category “created” than in clips they had assigned to the category “learnt,” supporting the idea of an influence of agency on self-recognition

Social Mechanisms in Epidemiological Publications on Small-Area Health Inequalities-A Scoping Review

Zolitschka KA, Razum O, Breckenkamp J, Sauzet O. Social Mechanisms in Epidemiological Publications on Small-Area Health Inequalities-A Scoping Review. FRONTIERS IN PUBLIC HEALTH. 2019;7: 393.Background: Small-area social mechanisms-social processes involving the social environment around the place of residence-may be playing a role in the production of health inequalities. Understanding how small-area health inequalities (social environment affects health and consequently contribute to inequalities between areas) are generated and the role of social mechanisms in this process may help defining interventions to reduce inequalities. In mediation and pathway analyses, social mechanisms need to be treated as processes or factors. We aimed to identify which types of social mechanisms explaining the process leading from small-area characteristics to health inequalities have been considered and investigated in epidemiological publications and to establish how they have been operationalized. Methods: We performed a scoping review for social mechanisms in the context of small-area health inequalities in the database PubMed. Epidemiological publications identified were categorized according to the typology proposed by Galster (social networks, social contagion, collective socialization, social cohesion, competition, relative deprivation, and parental mediation). Furthermore, we assessed whether the mechanisms were operationalized at the micro or macro level and whether mechanisms were considered as processes or merely as exposure factors. Results: We retrieved 1,019 studies, 15 thereof were included in our analysis. Eight forms of operationalization were found in the category social networks and another nine in the category social cohesion. Other categories were hardly represented. Furthermore, all studies were cross sectional and did not consider mechanisms as processes. Except for one, all studies treated mechanisms merely as factors whose respective association to health outcomes was tested. Conclusion: In epidemiological publications, social mechanisms in studies on small-area effects on health inequalities are not operationalized as processes in which these mechanisms would play a role. Rather, the focus is on studying associations. To understand the production of health inequalities and the causal effect of social mechanisms on health, it is necessary to analyze mechanisms as processes. For this purpose, methods such as complex system modeling should be considered

Treatment of elevated cholesterol in a representative cross-sectional sample of 4 892 Germans: is there a social gradient?

Background: effective control of cardiovascular risk factors remains low in most countries and also in Germany. We investigate whether socio-economic status has an impact on the level of medical treatment and control (normalized values) of total cholesterol. Methods: data on blood lipids from 4 892 participants in the last German Health Survey of 1998 are analysed, adjusting for key determinants in logistic regression analyses. Socio-economic status is not determined by educational achievement alone but also including occupation and household income. Results: the actual prevalence of total cholesterol of ≥240 mg/dl was 53.4%. Only 3.6% of prevalent cases are under effective treatment. Less favourable values of total cholesterol and HDL are displayed by males and in lower social groups, while the middle groups are in an intermediate position. Chances to be treated for hypercholesterolemia are significantly less favourable for females (odds ratio (OR) estimate: 0.70) and better for the age bands ≥50 (OR 2.37) and ≥60 (OR 3.57), if a general practitioner is visited (OR 1.77), and if living in Eastern Germany (OR 1.89). However, chances are not significantly different according to social status. Conclusions: statistically significant social group differences cannot be detected at the present low level of effective treatment. This may be different if higher levels of control are achieved