Boys and Girls on the Playground: Sex Differences in Social Development Are Not Stable across Early Childhood

Sex differences in human social behaviors and abilities have long been a question of public and scientific interest. Females are usually assumed to be more socially oriented and skilful than males. However, despite an extensive literature, the very existence of sex differences remains a matter of discussion while some studies found no sex differences whereas others reported differences that were either congruent or not with gender stereotypes. Moreover, the magnitude, consistency and stability across time of the differences remain an open question, especially during childhood. As play provides an excellent window into children's social development, we investigated whether and how sex differences change in social play across early childhood. Following a cross-sectional design, 164 children aged from 2 to 6 years old, divided into four age groups, were observed during outdoor free play at nursery school. We showed that sex differences are not stable over time evidencing a developmental gap between girls and boys. Social and structured forms of play emerge systematically earlier in girls than in boys leading to subsequent sex differences in favor of girls at some ages, successively in associative play at 3–4 years, cooperative play at 4–5 years, and social interactions with peers at 5–6 years. Preschool boys also display more solitary play than preschool girls, especially when young. Nevertheless, while boys catch up and girls move on towards more complex play, sex differences in social play patterns are reversed in favor of boys at the following ages, such as in associative play at 4–5 years and cooperative play at 5–6 years. This developmental perspective contributes to resolve apparent discrepancies between single-snapshot studies. A better understanding of the dynamics of sex differences in typical social development should also provide insights into atypical social developments which exhibit sex differences in prevalence, such as autism

Creative Perspectives Towards Trans-disciplinary Learning Models: Clothing as a Medium for Creative Enhancement and Education

As a significant part of childhood material culture, children’s clothes and their design contribute to shaping their social identity, gender, age, as well as to developing their senses of and supporting their interactions with their environment. IN2FROCC gathers together historians, anthropologists, sociologists, ethnologists, museum curators, childhood practitioners, designers, industry representatives, in a hub for the research and experimentation into children’s clothes across the globe, time and social ecosystems. This international and interdisciplinary network seeks to engage in an innovative, inclusive and organic manner with current research on children’s dress codes, fashion and clothes. Original in its approach, IN2FROCC opens up to practice-based research, in order to inform the mechanisms involved in design processes and children’s interactions with their material environment. Developed as part of this programme, and with a specific focus on child-led action research, projects such as “Tell me”, explore more precisely the learning potential of clothes for children, enhancing the opportunities provided by this socialising tool to support educators creatively and raise the environmental and cultural awareness of future responsible citizens

Effect of puckering motion and hydrogen bond formation on the vibrational circular dichroism spectrum of a flexible molecule: the case of ( S )-1-indanol

International audienceThe influence of flexibility and hydrogen bond formation on the IR absorption and vibrational circular dichroism (VCD) spectrum of a floppy protic molecule, namely, (S)-1-indanol, is studied in both non-polar CCl 4 and polar DMSO solvents. The experimental IR absorption and VCD spectra obtained by Fourier transform spectroscopy are interpreted using both static density functional theory (DFT) calculations and first principles molecular dynamics (FPMD) within DFT, using the nuclear velocity perturbation theory (NVPT). Simulation of the spectra based on static optimised geometries is not sufficient in CCl 4 and going beyond static calculations is mandatory for satisfactorily reproducing the VCD spectra. The FPMD results obtained in DMSO indicate that (S)-1-indanol is hydrogen-bonded to one DMSO molecule. As a result, static "cluster-in-the-bulk" DFT calculations in which the solute-solvent interaction is modeled as the most stable (S)-1-indanol:DMSO-d6 complexes in a DMSO continuum yield satisfactory agreement with the experiment. Correspondence between experimental and simulated spectra is slightly improved when the VCD spectrum is calculated as the summed contributions of snapshots extracted from FPMD trajectories, due to better sampling of the potential-energy surface. Finally, NVPT calculations further improve the description of experimental spectra by taking into account higher-energy structures, which are not necessary local minima

Corrosion sous contrainte assistée par l'irradiation en milieu primaire d'aciers inoxydables austénitiques

National audienceLes internes de cuves des REP sont soumis à divers modes de sollicitation, notamment de corrosion sous contrainte assistée par l'irradiation (IASCC). L'objectif de ce travail est d'étudier le couplage de plusieurs phénomènes physiques et chimiques interagissant en IASCC. En particulier, nous nous intéresserons au couplage microstructure (hétérogénéités chimique, cristallographique, nature des joints de grains...) / mécanismes de déformation / mécanismes d'irradiation / effet de l'environnement / champs mécaniques. Nous présenterons notamment la méthodologie et les premiers résultats concernant l'irradiation aux protons sur matériau massif et les essais de corrosion sous contrainte associés ; ainsi que la méthodologie concernant l'irradiation de lames minces qui sera effectuée sur la plate-forme JANNUS du CSNSM, où le matériau sera exposé simultanément à un faisceau d'irradiation et un faisceau d'implantation d'hélium

Excited States of Proton-bound DNA/RNA Base Homo-dimers: Pyrimidines

We are presenting the electronic photo fragment spectra of the protonated pyrimidine DNA bases homo-dimers. Only the thymine dimer exhibits a well structured vibrational progression, while protonated monomer shows broad vibrational bands. This shows that proton bonding can block some non radiative processes present in the monomer.Comment: We acknowledge the use of the computing facility cluster GMPCS of the LUMAT federation (FR LUMAT 2764

The improbable transmission of Trypanosoma cruzi to human: the missing link in the dynamics and control of Chagas disease

Chagas disease has a major impact on human health in Latin America and is becoming of global concern due to international migrations. Trypanosoma cruzi, the etiological agent of the disease, is one of the rare human parasites transmitted by the feces of its vector, as it is unable to reach the salivary gland of the insect. This stercorarian transmission is notoriously poorly understood, despite its crucial role in the ecology and evolution of the pathogen and the disease. The objective of this study was to quantify the probability of T. cruzi vectorial transmission to humans, and to use such an estimate to predict human prevalence from entomological data. We developed several models of T. cruzi transmission to estimate the probability of transmission from vector to host. Using datasets from the literature, we estimated the probability of transmission per contact with an infected triatomine to be 5.8x10(-4) (95%CI: [2.6; 11.0] x 10(-4)). This estimate was consistent across triatomine species, robust to variations in other parameters, and corresponded to 900-4,000 contacts per case. Our models subsequently allowed predicting human prevalence from vector abundance and infection rate in 7/10 independent datasets covering various triatomine species and epidemiological situations. This low probability of T. cruzi transmission reflected well the complex and unlikely mechanism of transmission via insect feces, and allowed predicting human prevalence from basic entomological data. Although a proof of principle study would now be valuable to validate our models' predictive ability in an even broader range of entomological and ecological settings, our quantitative estimate could allow switching the evaluation of disease risk and vector control program from purely entomological indexes to parasitological measures, as commonly done for other major vector borne diseases. This might lead to different quantitative perspectives as these indexes are well known not to be proportional one to another

DFB Lasers Between 760 nm and 16 μm for Sensing Applications

Recent years have shown the importance of tunable semiconductor lasers in optical sensing. We describe the status quo concerning DFB laser diodes between 760 nm and 3,000 nm as well as new developments aiming for up to 80 nm tuning range in this spectral region. Furthermore we report on QCL between 3 μm and 16 μm and present new developments. An overview of the most interesting applications using such devices is given at the end of this paper