Strong spatial dispersion in wire media in the very large wavelength limit

It is found that there exist composite media that exhibit strong spatial dispersion even in the very large wavelength limit. This follows from the study of lattices of ideally conducting parallel thin wires (wire media). In fact, our analysis reveals that the description of this medium by means of a local dispersive uniaxial dielectric tensor is not complete, leading to unphysical results for the propagation of electromagnetic waves at any frequencies. Since non--local constitutive relations have been usually considered in the past as a second order approximation, meaningful in the short wavelength limit, the aforementioned result presents a relevant theoretical interest. In addition, since such wire media have been recently used as a constituent of some discrete artificial media (or metamaterials), the reported results open the question of the relevance of the spatial dispersion in the characterization of these artificial media.Comment: MiKTex, 4 pages with 2 figures, submitted to PR

A meeting report: cross-cultural comparability of questionnaire measures in large-scale international surveys

The value of cross-country comparisons is at the heart of large-scale international surveys. Yet the validity of such comparisons is often challenged, particularly in the case of latent traits whose estimates are based on self-reported answers to a small number of questionnaire items. Many believe self-reports to be unreliable and not comparable, and indeed, formal statistical procedures very often reject the assumption that the questions are understood and answered in the same way in different countries (measurement invariance). A methodological conference on the comparability of questionnaire scales was hosted by the OECD on 8 and 9 November 2018. This meeting report summarises the discussions held at the conference about measurement invariance testing and instrument design. The report first provides a brief introduction to the measurement models and the accompanying invariance analyses typically used in the industry of large-scale international surveys and points to the main limitations of these current standard approaches. It then presents classical and novel ways to deal with imperfect comparability of measurements when scaling and reporting on continuous traits and on categorical latent variables. It finally discusses the extent to which item design can improve the cross-country comparability of the measured constructs (e.g. by adopting innovative item formats such as anchoring vignettes and situational judgement test items). It concludes with some general considerations for survey design and reporting on invariance analyses and survey results

Dynamic nuclear polarization and spin-diffusion in non-conducting solids

There has been much renewed interest in dynamic nuclear polarization (DNP), particularly in the context of solid state biomolecular NMR and more recently dissolution DNP techniques for liquids. This paper reviews the role of spin diffusion in polarizing nuclear spins and discusses the role of the spin diffusion barrier, before going on to discuss some recent results.Comment: submitted to Applied Magnetic Resonance. The article should appear in a special issue that is being published in connection with the DNP Symposium help in Nottingham in August 200

Handheld computers for self-administered sensitive data collection: A comparative study in Peru

<p>Abstract</p> <p>Background</p> <p>Low-cost handheld computers (PDA) potentially represent an efficient tool for collecting sensitive data in surveys. The goal of this study is to evaluate the quality of sexual behavior data collected with handheld computers in comparison with paper-based questionnaires.</p> <p>Methods</p> <p>A PDA-based program for data collection was developed using Open-Source tools. In two cross-sectional studies, we compared data concerning sexual behavior collected with paper forms to data collected with PDA-based forms in Ancon (Lima).</p> <p>Results</p> <p>The first study enrolled 200 participants (18–29 years). General agreement between data collected with paper format and handheld computers was 86%. Categorical variables agreement was between 70.5% and 98.5% (Kappa: 0.43–0.86) while numeric variables agreement was between 57.1% and 79.8% (Spearman: 0.76–0.95). Agreement and correlation were higher in those who had completed at least high school than those with less education. The second study enrolled 198 participants. Rates of responses to sensitive questions were similar between both kinds of questionnaires. However, the number of inconsistencies (p = 0.0001) and missing values (p = 0.001) were significantly higher in paper questionnaires.</p> <p>Conclusion</p> <p>This study showed the value of the use of handheld computers for collecting sensitive data, since a high level of agreement between paper and PDA responses was reached. In addition, a lower number of inconsistencies and missing values were found with the PDA-based system. This study has demonstrated that it is feasible to develop a low-cost application for handheld computers, and that PDAs are feasible alternatives for collecting field data in a developing country.</p

Investigation of depression,life satisfaction and related factors of the elderly in Sichuan earthquake area

目的探讨5.12地震灾区老年人的抑郁情绪、生活满意度及其相关因素。方法5.12地震后8个月,采用Scl-90抑郁分量表、躯体化分量表、生活满意度量表以及心理韧性量表和社会支持量表对灾区的70名老年组被试和139名青年对照组被试进行施测。结果灾区老年人的抑郁得分略高于青年人(t=1.68,P=0.09),躯体化得分显著高于青年人(t=3.198,P<0.01),生活满意度得分显著高于青年人(t=6.20,P<0.001),老年人的心理韧性得分也显著高于青年人(t=3.11,P<0.01),而社会支持得分显著低于青年人(t=-3.29,P<0.01);心理韧性正向预测生活满意度(β=0.34,P<0.001),而与抑郁、躯体化无关,社会支持负向预测抑郁情绪(β=-0.33,P<0.001),同时正向预测生活满意度(β=0.19,P<0.001)和韧性(β=0.22,P<0.001)。结论与灾区青年人相比,灾区老年人同时表现出较高的抑郁情绪、躯体化和较高的生活满意度,这与老年人拥有较低的社会支持和较高的心理韧性有关,但心理韧性并不能帮助他们缓解抑郁情绪和躯体化,甚至还受到社会支持减少的潜在影响

Long-Term Effects of a U.S. University Human Sexuality Course on Use of Contraception

This study examined long-term effects of taking a university sexuality course on use of contraception. A questionnaire was given to two groups of students: 602 students enrolled in the first week of a comprehensive sexuality course, and 352 students who had completed the course 1&ndash;1.5 years earlier. A significantly smaller percentage of former students had used no contraception at last sexual intercourse (p &lt; 0.005). Former students were less likely to have used a dual method, and favored either IUDs, implants, or birth control pills used alone. There was no notable change in the percentage of former students using withdrawal or condoms. Former students showed evidence of better communication about sex with their partners. The effect size for use of contraception was small, but if this result is true of other college sexuality courses, nationwide it translates into thousands of students who may have avoided unintentional pregnancies

The Pharmacological Potential of Adenosine A _2A Receptor Antagonists for Treating Parkinson's Disease

The adenosine A2A receptor subtype is recognized as a non-dopaminergic pharmacological target for the treatment of neurodegenerative disorders, notably Parkinson&rsquo;s disease (PD). The selective A2A receptor antagonist istradefylline is approved in the US and Japan as an adjunctive treatment to levodopa/decarboxylase inhibitors in adults with PD experiencing OFF episodes or a wearing-off phenomenon; however, the full potential of this drug class remains to be explored. In this article, we review the pharmacology of adenosine A2A receptor antagonists from the perspective of the treatment of both motor and non-motor symptoms of PD and their potential for disease modification