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Patterns of cellular phone use among young people in 12 countries: Implications for RF exposure
Langer, Chelsea E.,de Llobet, Patricia,Dalmau, Albert,Wiart, Joe,Goedhart, Geertje,Hours, Martine,Benke, Geza P.,Bouka, Evdoxia,Bruchim, Revital,Choi, Kyung-Hwa,Eng, Amanda,Ha, Mina,Karalexi, Maria,Ki Elsevier 2017 Environment international Vol.107 No.-
<P><B>Abstract</B></P> <P>Characterizing exposure to radiofrequency (RF) fields from wireless telecommunications technologies during childhood and adolescence is a research priority in investigating the health effects of RF. The Mobi-Expo study aimed to describe characteristics and determinants of cellular phone use in 534 young people (10–24years) in 12 countries. The study used a specifically designed software application installed on smartphones to collect data on the use of wireless telecommunications devices within this age group. The role of gender, age, maternal education, calendar period, and country was evaluated through multivariate models mutually adjusting for all variables. Call number and duration were higher among females compared to males (geometric mean (GM) ratio 1.17 and 1.42, respectively), among 20–24year olds compared to 10–14year olds (GM ratio 2.09 and 4.40, respectively), and among lowest compared to highest social classes (GM ratio 1.52 and 1.58, respectively). The number of SMS was higher in females (GM ratio 1.46) and the middle age group (15–19year olds: GM ratio 2.21 compared to 10–14year olds) and decreased over time. Data use was highest in the oldest age group, whereas Wi-Fi use was highest in the middle age group. Both data and Wi-Fi use increased over time. Large differences in the number and duration of calls, SMS, and data/Wi-Fi use were seen by country, with country and age accounting for up to 50% of the variance. Hands-free and laterality of use did not show significant differences by sex, age, education, study period, or country. Although limited by a convenience sample, these results provide valuable insights to the design, analysis, and interpretation of future epidemiological studies concerning the health effects of exposure resulting from cellular phone use in young people. In addition, the information provided by this research may be used to design strategies to minimize RF exposure.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Number and duration of calls varied by sex, age range, and socioeconomic status </LI> <LI> Laterality and hands-free use were less influenced by user characteristics </LI> <LI> Country of origin explained most of the variance in number and duration of calls, as well as SMS and data/Wi-Fi </LI> </UL> </P>
LARGE SCALE MAGNETOGENESIS THROUGH RADIATION PRESSURE
LANGER MATHIEU,PUGET JEAN-LOUP,AGHANIM NABILA The Korean Astronomical Society 2004 Journal of The Korean Astronomical Society Vol.37 No.5
We present a new model for the generation of magnetic fields on large scales occurring at the end of cosmological reionisation. The inhomogeneous radiation provided by luminous sources and the fluctuations in the matter density field are the major ingredients of the model. More specifically, differential radiation pressure acting on ions and electrons gives rise to electric currents which induce magnetic fields on large scales. We show that on protogalactic scales, this process is highly efficient, leading to magnetic field amplitudes of the order of $10^{-1l}$ Gauss. While remaining of negligible dynamical impact, those amplitudes are million times higher than those obtained in usual astrophysical magnetogenesis models. Finally, we derive the relation between the power spectrum of the generated field and the one of the matter density fluctuations. We show in particular that magnetic fields are preferably created on large (galactic or cluster) scales. Small scale magnetic fields are strongly disfavoured, which further makes the process we propose an ideal candidate to explain the origin of magnetic fields in large scale structures.