Calculation of a point source radiation in a flat or non-flat stratified background: an alternative to Sommerfeld integrals

In this paper, we present an alternative method to Sommerfeld integrals for the calculation of a point source radiation in a multilayered background, based on the method of auxiliary sources, also called fictitious sources method. The method lies upon the decomposition of reflected and transmitted fields on a basis of secondary sources, which amplitudes are determined by applying boundary conditions at each multilayer interface, solving an over-determined system of equations. We present a generalization of the classical FSM to open stratified domains, with arbitrary number of layers and arbitrary position of the point source in the multilayer. Two and three dimensional formalisms are proposed, and compared to exact Sommerfeld formulation. Computation time reduction factors as high as 100 are obtained for 2D problems. Moreover, this method enables the study of non-flat interfaces, which is not possible with Sommerfeld approach. This method can be used for example in order to determine radiation efficiency of emitting devices, or it can be integrated in discrete source type electromagnetic methods for calculation of scattering by a complex target

High Output Nanometer Scale Focusing Device

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Validation of an analytical model of si-ring resonators for designing a 1×8 multiplexer in SCISSOR configuration

International audienceWe numerically simulate chromatic and thermal dispersion in ring-resonator-based filters and validate the model with experimental data. A low-loss 1×8 multiplexer based on SCISSORs structure was designed with a bandwidth of 200 GHz at -3 dB and a crosstalk better than -13.5 dB for each channel

Smoking cessation attempts: is it useful to treat hard core smokers?

Introduction Hard core smokers have been studied in many countries but only a few trials have compared the effectiveness of smoking cessation with other smokers. The objective of this study was to compare the frequencies of success in smoking cessation between hard-core smokers and other smokers. Material and Methods Data were collected in Clermont-Ferrand from the Emile Roux dispensary ‘Pneumology and Tobaccology Centre’ between 1999 and 2009. Assistance with smoking cessation was proposed to 1367 patients but only 1296 patients were included: 219 HCS and 1077 other smokers. Smoking cessation was considered a success when patients were abstinent 6 months after the beginning of cessation. The profiles of the two types of smokers were compared using Chi square test and Student’s t test. Multivariate logistic regression was used to investigate the association between the smoking cessation result and the type of smokers. Results HCS more frequently consumed other psychoactive substances (41.1 % vs 25.7 % for other smokers; p < 0.001). Current depression was more frequent in HCS (46.6 % vs 34.8 % for other smokers; p = 0.001). Smoking cessation was less frequent in HCS (45.2 % vs 56.5 % for other smokers ; p = 0.002). In multivariate analysis, after controlling for other factors, the frequency of smoking cessation was not significantly associated with the type of smokers (p = 0.47). After limiting to initial factors (present before the beginning of smoking cessation), the frequency of smoking cessation was still not significantly associated with the type of smokers (p = 0.78). Conclusions Smoking cessation is possible for hard core smokers, who should be treated as other types of smokers taking into account other factors:the problem is how to encourage them to try to stop smoking

J Prev Med Hyg

Introduction: Students overestimate alcohol consumption of those around them and underestimate their own, so that quantitative approach may not be the most relevant to assess students' drinking. The main objective was to provide an appropriate tool for screening for students with potential drinking problems. Methods: A multicentre cross-sectional survey was conducted by internet between February and June, 2013 in France. Thirteen questions explored alcohol consumption, including 8 concerning after-effects of drinking episodes (4 items of the AUDIT) and alcohol behaviour (CAGE test). A multiple correspondence analysis (MCA) was conducted to identify profiles of student's alcohol consumption. Partitioning methods were used to group students by mode of alcohol use. The most relevant items included in the MCA were identified. Three questions were identified as most pertinent among the students with potential drinking problems and ranked by a decision tree with the Chi-square Automatic Interaction Detector method. Finally, we assessed the generalisation of the model. Results: A total of 36,427 students participated in the survey: 25,679 were women (70.5% of respondents), sex ratio 0.42 and mean aged 21.2 (sd 3.7 years). Among those who had experimented with alcohol (N = 33,113), three consumption profiles were identified: "simple/non-use" (66.9%), "intermediate consumption" (25.9%) and "problem drinking" (7.2%). For the latter group, the three most relevant items were (Q20) "not able to stop drinking after starting", (Q21) "failed to do what was normally expected", and (Q23) "unable to remember what happened the night before". Conclusions: These results provide healthcare professionals with a 3-item screening tool for students "problem drinking"

Application of scatterometric porosimetry to characterize porous ultra low-k patterned layers

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