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This paper describes the analytical methodology for the determination of MDMA, MDA, MDEA and MBDB in oral fluid. After a liquid–liquid extraction, the analysis was carried out by high performance liquid chromatography (HPLC), with fluorescence detection. The detector wavelength was fixed at 285 nm for excitation and 320 nm for emission. The mobile phase, a mixture of phosphate buffer (pH = 5) and acetonitrile (75:25), and the column, Kromasil 100 C8 5 μm 250 mm × 4.6 mm, allowed good separation of the compounds in an isocratic mode in only 10 min. The method was validated and showed good limits of detection (2 ng/mL) and quantitation (10 ng/mL) for all the amphetamine derivatives. No interfering substances were detected. A stability study of these compounds in oral fluid stored at three different temperatures (−18, 4 and 20 °C) over 10 weeks was conducted, showing a time-dependent degradation of the four compounds.  相似文献   
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Surfmen are thus called young daredevils who climb to the roof of suburban trains in Rio de Janeiro, Brazil and vie with each other in agility and prowess, some of them often falling on the railway tracks and being killed. The practice started as a need to hang on anything outside the crowded train and became a sport of sorts. Even though repressed by the railway authorities and punished by fines and imprisonment, the practice has been going on since the eighties and developed into a competition with rules, code of honour, grading of achievement. It became a means of improving self-esteem as well as securing leadership and social prestige by people who otherwise carry on lives devoid of any charm or ludic stimulus. A substitute behavior, it results from processes of cultural elaboration at work in the youth culture of our cities.  相似文献   
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The purpose of this study was to examine in a sample of 11,516 secondary school students the extent to which different behavioral, emotional and cognitive problems (a) reflected one or more underlying common factors; (b) actually cooccurred; and (c) were single problems. Principal Component Analyses were performed and percentagewise techniques were used. PCA demonstrated that one or more general syndromes could not by far account for all of the variance of the variables. The results suggest the existence of adolescent subgroups with divergent comorbidity patterns: those who primarily report one single symptom; those who report concurrent symptoms either exclusively in the category of behavioral problems or exclusively in the category of emotional and cognitive problems; and those who report concurrent symptoms in both categories. This distinction between different subgroups has important theoretical, diagnostic, and treatment implications.  相似文献   
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This article addresses the rise of corporate citizenship in the context of the changes in the nature of individual citizenship and the emergence of new, non‐territorial forms of national identity that are occurring in the current era of intensifying globalization. It also ponders the power of corporate citizens and the role they play in the prevailing global governance framework, as well as the extent to which they can behave responsibly and pursue sustainable development goals. More generally, the article discusses the limits to corporate social responsibility and the extent to which capitalism can be ‘caring’. The argument advanced is that, by virtue of their very nature, transnational corporations (TNCs) cannot become fully responsible and accountable citizens. Nonetheless, they can be induced to transform themselves in ways that may be compatible with socially and environmentally desirable objectives. Lastly, the article explores paths for action and, in particular, the potential of NGOs and anti‐globalization social movements to become civil regulators able to push for the introduction of binding rules and regulations and the construction a governance framework capable of restraining and harnessing the power of TNCs.  相似文献   
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