947 resultados para Teenagers Sexual behavior


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A variety of behavioural traits have substantial effects on the gene dynamics and genetic structure of local populations. The mating system is a plastic trait that varies with environmental conditions in the domestic cat (Felis catus) allowing an intraspecific comparison of the impact of this feature on genetic characteristics of the population. To assess the potential effect of the heterogenity of males' contribution to the next generation on variance effective size, we applied the ecological approach of Nunney & Elam (1994) based upon a demographic and behavioural study, and the genetic 'temporal methods' of Waples (1989) and Berthier et al. (2002) using microsatellite markers. The two cat populations studied were nearly closed, similar in size and survival parameters, but differed in their mating system. Immigration appeared extremely restricted in both cases due to environmental and social constraints. As expected, the ratio of effective size to census number (Ne/N) was higher in the promiscuous cat population (harmonic mean = 42%) than in the polygynous one (33%), when Ne was calculated from the ecological method. Only the genetic results based on Waples' estimator were consistent with the ecological results, but failed to evidence an effect of the mating system. Results based on the estimation of Berthier et al. (2002) were extremely variable, with Ne sometimes exceeding census size. Such low reliability in the genetic results should retain attention for conservation purposes.

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The objective of this study is to review the health promotion interventions on spanish youths published in Spanish in the 1995-2000 period and to describe them in accordance with the scope within which they have been carried out, the topics addressed, the methodology, the evaluation design used and the results obtained. Two hundred and fourteen intervention were identified. Illegal drugs were the topic on which the largest number of interventions were focused (29.8%), followed by alcohol (15.9%), the risk-related sexual behaviours (14.6%) and leisure time (12.6%). The activities carried out most often were: participation-based educational methods (30.7%), explanatory education methods (11.5%) and the preparation of educational materials (11%). In 80.8% of the cases, some evaluation of the health promotion activities was found. The type of evaluation employed most often was the process evaluation (73.7%), and the medium-long term results evaluation being those employed the least (2.2%). The evaluation methodologies used most often were questionnaires (28.2%). A combination of qualitative and quantitative methods was employed in 13.2% of the cases. The four interventions in which the medium-long term impact was gauged had the purpose of preventing and reducing cigarette smoking and/or drinking and or marijuana smoking, all of these initiatives achieving a reduction in cigarette smoking. In conclusion, it seems necessary to improve the design of the evaluations of the health promotion initiatives addressed to young people in Spain and to increase the dissemination of the same by way of their publication.

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OBJECTIVES To evaluate the advantages of cytology and PCR of high-risk human papilloma virus (PCR HR-HPV) infection in biopsy-derived diagnosis of high-grade squamous intraepithelial lesions (HSIL = AIN2/AIN3) in HIV-positive men having sex with men (MSM). METHODS This is a single-centered study conducted between May 2010 and May 2014 in patients (n = 201, mean age 37 years) recruited from our outpatient clinic. Samples of anal canal mucosa were taken into liquid medium for PCR HPV analysis and for cytology. Anoscopy was performed for histology evaluation. RESULTS Anoscopy showed 33.8% were normal, 47.8% low-grade squamous intraepithelial lesions (LSIL), and 18.4% HSIL; 80.2% had HR-HPV. PCR of HR-HPV had greater sensitivity than did cytology (88.8% vs. 75.7%) in HSIL screening, with similar positive (PPV) and negative predictive value (NPV) of 20.3 vs. 22.9 and 89.7 vs. 88.1, respectively. Combining both tests increased the sensitivity and NPV of HSIL diagnosis to 100%. Correlation of cytology vs. histology was, generally, very low and PCR of HR-HPV vs. histology was non-existent (<0.2) or low (<0.4). Area under the receiver operating characteristics (AUROC) curve analysis of cytology and PCR HR-HPV for the diagnosis of HSIL was poor (<0.6). Multivariate regression analysis showed protective factors against HSIL were: viral suppression (OR: 0.312; 95%CI: 0.099-0.984), and/or syphilis infection (OR: 0.193; 95%CI: 0.045-0.827). HSIL risk was associated with HPV-68 genotype (OR: 20.1; 95%CI: 2.04-197.82). CONCLUSIONS When cytology and PCR HR-HPV findings are normal, the diagnosis of pre-malignant HSIL can be reliably ruled-out in HIV-positive patients. HPV suppression with treatment protects against the appearance of HSIL.

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BACKGROUND: Peer pressure is regarded as an important determinant of substance use, sexual behavior and juvenile delinquency. However, few peer pressure scales are validated, especially in French or German. Little is known about the factor structure of such scales or the kind of scale needed: some scales takes into account both peer pressure to do and peer pressure not to do, while others consider only peer pressure to do. The aim of the present study was to adapt French and German versions of the Peer Pressure Inventory, which is one of the most widely used scales in this field. We considered its factor structure and concurrent validity. METHODS: Five thousand eight hundred and sixty-seven young Swiss men filled in a questionnaire on peer pressure, substance use, and other variables (conformity, involvement) in a cohort study. RESULTS: We identified a four-factor structure, with the three factors of the initial Peer Pressure Inventory (involvement, conformity, misconduct) and adding a new one (relationship with girls). A non-valued scale (from no peer pressure to peer pressure to do only) showed stronger psychometric qualities than a valued scale (from peer pressure not to do to peer pressure to do). Concurrent validity was also good. Each behavior or attitude was significantly associated with peer pressure. CONCLUSION: Peer pressure seems to be a multidimensional concept. In this study, peer pressure to do showed the strongest influence on participants. Indeed, peer pressure not to do did not add anything useful. Only peer pressure to do affected young Swiss men's behaviors and attitudes and was reliable.

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Gaysurvey est une enquête menée périodiquement en Suisse parmi les hommes qui ont des relations sexuelles avec des hommes (HSH). Elle s'inscrit dans le dispositif de surveillance du VIH, établi par l'Office fédéral de la santé publique, en tant qu'instrument de suivi des comportements face au VIH/sida dans ce groupe-cible. Elle a déjà été réalisée à huit reprises. [Auteurs, p. 5] [Table des matières] 1. Résumé. 2. Zusammenfassung. 3. Introduction. 4. Méthodologie. 5. Résultats : Participation - Caractéristiques sociodémographiques - Activité sexuelle et comportements préventifs - Relations stables - Relations occasionnelles - Indicateur global d'exposition au risque - Test VIH - Séropositivité et comportements préventifs - Autres maladies infectieuses - VID/sida dans la vie quotidienne - Premiers contacts avec la prévention. 6. Conclusions. 7. Bibliographie. 8. Liste des tableaux et graphiques.

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Theory predicts that males adapt to sperm competition by increasing their investment in testis mass to transfer larger ejaculates. Experimental and comparative data support this prediction. Nevertheless, the relative importance of sperm competition in testis size evolution remains elusive, because experiments vary only sperm competition whereas comparative approaches confound it with other variables, in particular male mating rate. We addressed the relative importance of sperm competition and male mating rate by taking an experimental evolution approach. We subjected populations of Drosophila melanogaster to sex ratios of 1:1, 4:1, and 10:1 (female:male). Female bias decreased sperm competition but increased male mating rate and sperm depletion. After 28 generations of evolution, males from the 10:1 treatment had larger testes than males from other treatments. Thus, testis size evolved in response to mating rate and sperm depletion, not sperm competition. Furthermore, our experiment demonstrated that drift associated with sex ratio distortion limits adaptation; testis size only evolved in populations in which the effect of sex ratio bias on the effective population size had been compensated by increasing the numerical size. We discuss these results with respect to reproductive evolution, genetic drift in natural and experimental populations, and consequences of natural sex ratio distortion.

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Between the end of August and December 2013, an internet based survey named ANSWER will collect data about sexual health, sexual behavior and risk taking among Sub-Saharan African migrants (SSAm) living in Switzerland. This research is carried out by the Institut de médecine sociale et préventive (IUMSP, Lausanne) on a mandate from the Federal Offi ce of Public Health (FOPH), in cooperation with the Swiss Aids Federation (AHS) and other institutions addressing the prevention and information needs of the African population living in Switzerland.

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Purpose: Although young males encounter sexually-related concerns, they are mostly absent from specialized services. Our objective is to assess whether the internet is used by boys to find answers to these types of problems and questions. Methods: In the context of a qualitative study assessing young males' barriers to access sexual and reproductive health facilities, we conducted two focus groups gathering 12 boys aged 17-20. Discussions were triggered through the presentation of four vignettes corresponding to questions posted by 17-20 year old boys and girls on an information website for adolescents (www.ciao.ch), concerning various sexual dysfunction situations. In order to avoid having to talk about their own experience, participants were asked what they would do in those cases. Results: In general, the internet was mentioned quite thoroughly as a means of searching for information through research engines and a place to address professionals for advice.Within the hierarchy of consultation possibilities, the internet was given the first place as a way to deal with these types of problems presenting many advantages: (1) the internet enables to maintain intimacy; (2) it is anonymous (use of a pseudo); (3) it avoids having to confront someone face-to-face with personal problems which can be embarrassing and challenging for one's pride; (4) it is free; and (5) it is accessible at all times. In other words, participants value the internet as a positive tool to avoid many barriers which prevent offline consultations to take place. Most participants consider the internet at least as a first step in trying to solve a problem; for instance, by better defining the seriousness of a problem and judging if it is worth consulting a doctor. However, despite the positive qualities of the internet, they do put forward the importance of having specialists answering questions, trustworthiness, and being followed-up by the same person. Participants suggested that a strategy to break down barriers for boys to consult in face-to-face settings is to have a consultation on the internet as a first step which could then guide the person to an in-person consultation if necessary. Conclusions: The internet as a means of obtaining information or consulting received high marks overall. Although the internet cannot replace an in-person consultation, the screen and the keyboard have the advantage of not involving a face-to-face encounter and raise the possibility of discussing sexual problems anonymously and in private. The internet tools together with other new technologies should continue to develop in a secure manner as a space providing prevention messages and to become an easy access door to sexual and reproductive health services for young men, which can then guide youths to appropriate resource persons. Sources of support: This study was supported by the Maurice Chalumeau Foundation, Switzerland.

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Habitat restoration measures may result in artificially high breeding density, for instance when nest-boxes saturate the environment, which can negatively impact species' demography. Potential risks include changes in mating and reproductive behaviour such as increased extra-pair paternity, conspecific brood parasitism, and polygyny. Under particular cicumstances, these mechanisms may disrupt reproduction, with populations dragged into an extinction vortex. With the use of nuclear microsatellite markers, we investigated the occurrence of these potentially negative effects in a recovered population of a rare secondary cavity-nesting farmland bird of Central Europe, the hoopoe (Upupa epops). High intensity farming in the study area has resulted in a total eradication of cavity trees, depriving hoopoes from breeding sites. An intensive nest-box campaign rectified this problem, resulting in a spectacular population recovery within a few years only. There was some concern, however, that the new, high artificially-induced breeding density might alter hoopoe mating and reproductive behaviour. As the species underwent a serious demographic bottleneck in the 1970-1990s, we also used the microsatellite markers to reconstitute the demo-genetic history of the population, looking in particular for signs of genetic erosion. We found i) a low occurrence of extra-pair paternity, polygyny and conspecific brood parasitism, ii) a high level of neutral genetic diversity (mean number of alleles and expected heterozygosity per locus: 13.8 and 83%, respectively) and, iii) evidence for genetic connectivity through recent immigration of individuals from well differentiated populations. The recent increase in breeding density did thus not induce so far any noticeable detrimental changes in mating and reproductive behaviour. The demographic bottleneck undergone by the population in the 1970s-1990s was furthermore not accompanied by any significant drop in neutral genetic diversity. Finally, genetic data converged with a concomitant demographic study to evidence that immigration strongly contributed to local population recovery.

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Background: Second generation surveillance is a central feature of HIV/AIDS policy in Switzerland. Behavioural surveys in the general population, men having sex with men (MSM) and injecting drug users (IDU) have been regularly conducted since the early nineties. After peaking at 2144 cases in 1991, the number of new HIV cases notified to the Ministry of Health decreased in each subpopulation until 2000 (n=578) and then rose again to 735 in 2006. The recent increase is mainly due to MSM. Methods: In the general population, representative cross-sectional telephone surveys have been conducted 11 times since 1987. Surveys in convenience samples of MSM, recruited through gay newspapers and gay organisations, have been conducted 5 times since 1992. Surveys among IDU's attending needle exchange programmes have been conducted 5 times since 1993. Condom statistics, available since 1986, are included in the behavioural surveillance system. Results: In the general population aged 17-30, systematic condom use with casual partners in the last six months increased from 8.0% in 1987 to 75.8% in 2007. The proportion of MSM reporting anal intercourse with casual partners in the last 12 months increased from 61% in 1992 to 79% in 2007 (lowest value 56% in 1994) and unprotected anal intercourse with these partners increased from 14 % in 1992 to 24% in 2007 (lowest value 9% in 1994). The proportion of IDUs reporting borrowing used injection equipment decreased from 16.5% in 1993 to 8.9% in 2006. The ratio condoms released to retail/population aged 15-65 increased from 1.68 in 1986 to 3.8 in 2006. Conclusions: It has been possible to maintain a coherent behavioural surveillance system on a long-term basis, allowing for the monitoring of HIV prevention policy outcome and forseeing the development and distribution of new HIV cases in the population.

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In der Schweiz gibt es seit 1987 periodisch wiederholte Studien über das Sexualverhalten verschiedener Bevölkerungsgruppen. Damit lassen sich HIV-/STIrelevantes Verhalten sowie die Entwicklung anderer wichtiger Parameter der sexuellen Gesundheit beobachten. Der vorliegende Beitrag entstand auf der Grundlage des neuesten Berichts über das Monitoring der Schweizer Präventionsstrategie gegen HIV/Aids]. Er liefert einen Überblick über das Sexual- und Schutzverhalten von 17-bis 20-jährigen Jugendlichen und vergleicht die entsprechenden Parameter mit jenen anderer Altersgruppen.

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QUESTIONS UNDER STUDY/PRINCIPLES: Little is known concerning patients' expectations regarding sexual history taking by doctors: to ascertain expectations and actual experience of talking about sexuality among male patients attending outpatient clinics, and their sexual behaviour. METHODS: Patients consecutively recruited from two outpatient clinics in Lausanne, Switzerland were provided with an anonymous self-administered questionnaire. Survey topics were: patients' expectations concerning sexual history taking, patients' lifetime experience of sexual history taking, and patients' sexual behaviour. RESULTS: The response rate was 53.0% (N = 1452). Among respondents, 90.9% would like their physician to ask them questions regarding their sexual history in order to receive advice on prevention (60.0% yes, 30.9% rather yes). Fifteen percent would be embarrassed or rather embarrassed if asked such questions. Nevertheless, 76.2% of these individuals would like their physician to do so. Despite these wishes, only 40.5% reported ever having a discussion "on their sexual life in general" with a doctor. Only one patient out of four to five was asked about previous sexually transmitted infections (STIs), the number of sexual partners and their sexual orientation. No feature of their sexual life distinguishes those who had discussed sexual issues with a doctor from those who had not, except a history of previous consultation for health problems related to sexuality. Conversely, being embarrassed about conducting this discussion was significantly associated with lack of discussion regarding sexuality. CONCLUSIONS: This study highlights the gap existing in the field of STI prevention in terms of doctors' advice and patients' wishes.

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An EC concerted action on the assessment of AIDS/HIV prevention strategies was conducted between 1989 and 1992. The aim of this concerted action (CA) was to bring together researchers who are active in this assessment field, make an initial appraisal of the results of AIDS prevention efforts, in various population groups in Europe and develop an assessment methodology. Five areas of study were selected for the CA: the population as a whole ("general population"), men who have sexual relations with other men, intravenous drug users, migrant populations, monitoring of sexually transmitted diseases (STDs) to determine changes in behaviour. For each of these areas, a working group composed of the leading researchers in the field in Europe was constituted and commissioned by the project administration and coordination team to collate and analyse data on prevention efforts and their assessment in different countries of Europe. This review presents the main results from the groups responsible in each area in the concerted action. A number of general conclusions from the results of this concerted action are drawn.

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In order to investigate the determinants of effective population size in the socially monogamous Crocidura russula, the reproductive output of 44 individuals was estimated through genetic assignment methods. The individual variance in breeding success turned out to be surprisingly high, mostly because the males were markedly less monogamous than expected from previous behavioural data. Males paired simultaneously with up to four females and polygynous males had significantly more offspring than monogamous ones. The variance in female reproductive success also exceeded that of a Poisson distribution (though to a lesser extent), partly because females paired with multiply mated males weaned significantly more offspring. Polyandry also occurred occasionally, but only sequentially (i.e. without multiple paternity of litters). Estimates of the effective to census size ratio were ca. 0.60, which excluded the mating system as a potential explanation for the high genetic variance found in this shrew's populations. Our data suggest that gene flow from the neighbourhood (up to one-third of the total recruitment) is the most likely cause of the high levels of genetic diversity observed in this shrew's subpopulations.

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Gaysurvey est une enquête menée périodiquement en Suisse parmi les hommes qui ont des relations sexuelles avec des hommes (HSH). Elle s'inscrit dans le dispositif de surveillance du VIH, établi par l'Office fédéral de la santé publique, en tant qu'instrument de suivi des comportements face au VIH/Sida dans ce groupe cible. Elle a déjà été réalisée à neuf reprises : en 1987, 1990, 1992, 1994, 1997, 2000, 2004, 2007 et 2009. En 2010, l'enquête européenne EMIS a permis d'obtenir certains indicateurs qui sont présentés avec les données des enquêtes Gaysurvey lorsqu'ils sont disponibles. Les résultats de cette enquête servent directement au pilotage et à l'évaluation de la stratégie de lutte contre le VIH/Sida en Suisse, telle qu'elle a été définie par l'OFSP et ses partenaires. Elle permet d'établir des tendances temporelles au niveau des pratiques sexuelles et des expositions au risque d'infection par le VIH. Elle permet, en outre, d'approfondir certaines thématiques pertinentes pour le travail de prévention (gestion du risque au sein d'une relation stable, entrée dans la sexualité, pratiques de réduction des risques). Ce rapport a pour objectif de faire la synthèse des tendances, mises à jour lors de la dernière vague d'enquête réalisée en 2012. [Introduction p. 17]