Search

International audience

International audience; Objectives: To study valve appearance and the presence of valve disease in a cohort of people living with HIV (PLHIV).Design: A prospective study of PLHIV examined at the cardiology department of the Clermont Ferrand university hospital group (CHU) between January 1, 2012, and December 31, 2014. Were excluded those with a history of infection associated with a possible endocarditis.Methods: Demographic, medical characteristics and cardiovascular disease risk factors at time of cardiovascular examination and Doppler-echocardiography were recorded and analyzed.Results: In total, 903 PLHIV were examined in the infectious diseases department, 255 of whom were included. These consisted of 67 women (26.3%) and 188 men, of a mean age of 51.2 ±9.7 years, in whom coronary artery disease was diagnosed in 18 patients (7.0%), two women and 16 men, representing a prevalence of 3.0% in females and 8.5% in males. The appearance of the aortic cusps was considered dystrophic in 14.1% of cases (36/ 255), dysplastic in two cases (0.8%), exhibiting a bicuspid deformity in one case. The prevalence of aortic valve abnormality was therefore 6.0% in the women (4/67) and 17.0% in the men (32/188). On facing off this data with the Kora Monica study findings, an increase in prevalence appears only to truly manifest after 50 years of age.We registered 35 aortic insufficiency cases (13.7%), representing a higher incidence than that of the Framingham cohort, with age and masculine gender being the determining factors.Conclusion: Valve disease, along with coronary artery disease, should be closely monitored in PLHIV.

International audience; Background: Cancer has always been a major domain requiring progress in statistics, methodology and bio-informatics. Oncogenetic, focusing on the relationship between genetics and cancer, is particularly concerned with “big data” issues, which includes genealogical pedigrees: their special structure – made of relations between members and possible clinical annotations - is too complex to be directly used for statistical purpose. This article describes a way to condense pedigrees so that they can be handled more easily and compared together.Method: our approach aggregates the genealogical and clinical information of pedigrees containing many generations. Condensed pedigrees, called “subtrees”, are composed of basic 2 or 3-generation pedigrees: for one whole pedigree, a subtree is calculated by the mean of all basic pedigrees it contains. These subtrees can then be grouped together for different subsets of families (for example breast/ovarian cancer families with or without BRCA mutation carrier). Such a grouping named “profile”, besides its reduced structure, is particularly interesting because for each studied characteristic, means and standard deviations are available. Moreover, distances between each subtree and various profiles can be calculated and used as a discriminant index.Results: Subtrees and profiles were validated using a subset of 454 families (22.348 members) with a Lynch syndrome: in 84, at least one member carried an MMR deleterious mutation. Two profiles were computed depending on the presence or the absence of MMR mutation in the families. An ROC analysis showed that distances between each family subtree and both profiles were significant predictors for MMR mutations.Conclusion: Subtrees and profiles show interesting discriminant properties to study pedigree data. This method seems suitable to search for population differences between monogenic cancer risk models and multigenic ones.

International audience; Objectives: Compare tomosynthesis to mammography, ultrasound, MRI, and histology for the detection and staging of BI-RADS 4—5 anomalies, as a function of breast composition, lesion location, size, and histology.Patients and methods: Seventy-five patients underwent mammography, tomosynthesis, ultrasound, and MRI. The diagnostic accuracy of the different examinations was compared.Results: The sensitivities for detection were as follows: 92.5% with MRI, 79% for ultrasound, 75% for tomosynthesis, and 59.5% for mammography. Tomosynthesis improves the sensitivity of mammography (P = 0.00013), but not the specificity. The detection of multifocality and multicentricity was improved, but not significantly. Tomosynthesis identified more lesions than mammography in 10% of cases and improved lesion staging irrespective of the density, but was still inferior to MRI. The detection of ductal neoplasia was superior with tomosynthesis than with mammography (P = 0.016), but this was not the case with lobular cancer. The visualization of masses was improved with tomosynthesis (P = 0.00012), but not microcalcifications. Tomosynthesis was capable of differentiating lesions of all sizes, but the smaller lesions were easier to see. Lesion sizes measured with tomosynthesis, excluding the spicules, concurred with histological dimensions. Spicules lead to an overestimation of the size.Conclusion: In our series, tomosynthesis found more lesions than mammography in 10% of patients, resulting in an adaption of the surgical plan.

International audience; The aim of this study was to provide a better understanding of the scaffolding activity of instructors during driving lessons in a French urban traffic context. It focuses on three common and risky tasks: turning right, turning left and overtaking. Data were based on fine-grained longitudinal analyses of the records of five driving lessons involving four student-instructor dyads. The instructor scaffolding activity was analyzed throughout training e an original approach in the sphere of driving. The results show that the instructors implemented the learning process using an integrative approach based on‘cutting’ and ‘decoupling’ the driving task rather than the step-by-step method recommended in the curriculum. They transferred the responsibility of the driving components to the students in a similar order: 1) technical maneuvers, 2) situation identification and 3) goals focusing on other road users. As expected, student autonomy and efficiency in driving increased as the training progressed.However, at the end of training, uncertainties remained with regard to the execution of basic sub-goals in complex situation; moreover, the instructors were still in charge of the navigational task. The results were discussed and suggestions were made to improve instructor training with a view to increasing their efficiency in teaching students.

Promoting self-assessment accuracy among student drivers could help improve road safety for young novice drivers (Minimum Requirement for Driving Instructor Training, 2005). It is crucial to investigate the development of this ability in student drivers, although few studies have been conducted on this issue to our knowledge. The present study was aimed at examining the development of accuracy in student drivers' self-assessments. Students' self-ratings of their skills were compared to instructors' ratings based on the students' progression through the four steps of the French driver training course. The ratings were collected from two versions of an ad hoc questionnaire about students' ability to turn right, overtake another vehicle, and turn left in driving situations. The questionnaire included a three-part assessment scale (six driving subtasks required to perform the maneuver, the number of driving subtasks managed simultaneously, and the student's autonomy), demographic data, and the students' progress in the training program. The participants were 149 student drivers (58 men and 91 women) with a mean age of 22.2 years, and 38 professional driving instructors (36 men and 2 women) from 13 driving schools in Paris. The psychometric quality of the scale was satisfactory (α(s)>.9) concerning the self-ratings as well as the instructors' ratings in the three parts of the scale. As a whole and as expected, the self-ratings and the instructors' ratings became increasingly positive as the training progressed, on each part of the assessment scale. The students' and the instructors' ratings did not differ significantly between the three driving situations tested, nor between male and female students in each training step. Furthermore, students' overestimation of their driving skills was mainly observed on step 1, less on steps 2 and 3, but never on step 4. Thus, the students became rather aware of their current driving skills as the driver training course progressed. The results on the development of the self-assessment accuracy in driver training are discussed.

International audience

Taxonomy Based modeling was applied to describe drivers' mental models of variable message signs (VMS's) displayed on expressways. Progress in road telematics has made it possible to introduce variable message signs (VMS's). Sensors embedded in the carriageway every 500m record certain variables (speed, flow rate, etc.) that are transformed in real time into "driving times" to a given destination if road conditions do not change. VMS systems are auto-regulative Man-Machine (AMMI) systems which incorporate a model of the user: if the traffic flow is too high, then drivers should choose alternative routes. In so doing, the traffic flow should decrease. The model of the user is based on suppositions such as: people do not like to waste time, they fully understand the displayed messages, they trust the displayed values, they know of alternative routes. However, people also have a model of the way the system functions. And if they do not believe the contents of the message, they will not act as expected. We collected data through interviews with drivers using the critical incidents technique (Flanagan, 1985). Results show that the mental models that drivers have of the way the VMS system works are various but not numerous and that most of them differ from the "ideal expert" mental model. It is clear that users don't have an adequate model of how the VMS system works and that VMS planners have a model of user behaviour that does not correspond to the behaviour of the drivers we interviewed. Finally, Taxonomy Based Modeling is discussed as a tool for mental model remediation., Cet article aborde, au travers d'enquêtes auprès de conducteurs, leur modèle mental et leur perception des panneaux à messages variables

International audience; This paper describes the design principles of a microworld devoted to the manipulation of algebraic expressions. This microworld contains an advanced editor with classical actions and direct manipulation. Most of the actions are available in two or three modes; the three action modes are: a text mode that manipulates characters, a structure mode that takes care of the algebraic structure of the expressions, and an equivalence mode that takes into account the equivalence between the expressions. The microworld also allows to represent reasoning trees. The equivalence of the expressions built by the student is evaluated and the student is informed of the result. The paper also describes the current state of the implementation of the microworld. A first prototype has been realised at the beginning of February 2001.

International audience; Cet article décrit les principes de conception d'un micromonde dédié à la manipulation d'expressions algébriques. Ce micromonde contient un éditeur avancé avec des actions classiques et de la manipulation directe. La plupart des actions fonctionnent dans deux ou trois modes, les trois modes d'action étant : un mode "texte" qui manipule des caractères, un mode "structure" qui prend en compte la structure des expressions et un mode "équivalent" qui conserve l'équivalence des expressions. Le micromonde permet aussi de représenter des arbres de raisonnement. L'équivalence des expressions construites par l'élève est évaluée et l'élève est informé du résultat. L'article décrit aussi l'état actuel de la réalisation du micromonde dont le premier prototype a été opérationnel en février 2001.

This paper describes a research work whose objective is to help students to learn algebra with a computer. Firstly, we summarise the theoretical foundations and we describe a prototype devoted to the factoring problem. With this prototype, the student solves problems without making the calculations. The student can also observe the system solving a problem and providing explanations. Secondly, we summarise several experiments we carried out with students and we describe the results we got. Last, we present our new objective that consists of making a product that will be available for all students and teachers.