90 resultados para proporção sexual
Resumo:
OBJECTIVES: High prevalence of trauma has been reported in psychosis. While role of trauma as a risk factor for developing psychosis is still debated, its negative impact on outcome has been described. Few studies have explored this issue in first-episode psychosis (FEP) patients. We assessed rate of stressful events, as well as premorbid and outcome correlates of past sexual and/or physical abuse (SPA) in an epidemiological FEP patients cohort. METHODS: The Early Psychosis Prevention and Intervention Centre admitted 786 FEP patients between 1998 and 2000. Data were collected from patients' files using a standardized questionnaire. A total of 704 files were available, 43 excluded because of a nonpsychotic diagnosis at end point and 3 due to missing data regarding past stressful events; 658 patients were analyzed. RESULTS: A total of 83% patients had been exposed to at least one stressful event and 34% to SPA. SPA patients were more likely to have presented other psychiatric disorders before psychosis onset (posttraumatic stress disorder, substance use disorder), to have made suicide attempts in the past, and to have had poorer premorbid functional levels. Additionally, SPA patients had higher rate of comorbid diagnosis at program entry and were more likely to attempt suicide during treatment. CONCLUSIONS: SPA prevalence is high in FEP patients and must be explored by clinicians considering its durable impact on psychological balance and link with long-lasting suicidal risk. More research is warranted to better understand mechanisms involved between trauma and its potential consequences, as well as to develop psychological interventions adapted to this very sensitive and complex issue.
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This study aimed to compare the sexual behavior of adolescents who were or were not exposed to online pornography, to assess to what extent the willingness of exposure changed these possible associations, and to determine the profiles of youths who were exposed to online pornography. Data were drawn from the 2002 Swiss Multicenter Adolescent Survey on Health, a self-administered cross-sectional, paper and pencil questionnaire. From the 7529 adolescents aged 16-20 years, 6054 (3283 males) used the Internet during the previous month and were eligible for our study. Males were divided into three groups (wanted exposure, 29.2%; unwanted exposure, 46.7%; no exposure, 24.1%) whereas females were divided into two groups (exposure, 35.9%; no exposure, 64.1%). The principal outcome measures were demographic characteristics, Internet use parameters and risky sexual behaviors. Risky sexual behaviors were not associated with online pornography exposure in any of the groups, except that males who were exposed (deliberately or not) had higher odds of not having used a condom at last intercourse. Bi/homosexual orientation and Internet use parameters were not associated either. Additionally, males in the wanted exposure group were more likely to be sensation-seekers. On the other hand, exposed girls were more likely to be students, higher sensation-seekers, early maturers, and to have a highly educated father. We conclude that pornography exposure is not associated with risky sexual behaviors and that the willingness of exposure does not seem to have an impact on risky sexual behaviors among adolescents.
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Gender identity disorder is defined as a permanent desire to relieve one's own sexual features to acquire the sexual features and line to life of the opposite sex. The diagnosis is based on the psychiatric evaluation and treatment on an interdisciplinary approach by endocrinologists, surgeons and psychiatrists, and can be conceptualized into distinct phases: diagnostic evaluation, real life experience, hormonal treatment and surgery. Multiples challenges have to be faced, especially by the psychiatrist who follows the patient during the whole process.
Resumo:
Background and Aims Male-biased sex allocation commonly occurs in wind-pollinated hermaphroditic plants, and is often positively associated with size, notably in terms of height. Currently, it is not well established whether a corresponding pattern holds for dioecious plants: do males of wind-pollinated species exhibit greater reproductive allocation than females? Here, sexual dimorphism is investigated in terms of life history trade-offs in a dioecious population of the wind-pollinated ruderal herb Mercurialis annua.Methods The allocation strategies of males and females grown under different soil nutrient availability and competitive (i.e. no, male or female competitor) regimes were compared.Key Results Male reproductive allocation increased disproportionately with biomass, and was greater than that of females when grown in rich soils. Sexual morphs differentially adjusted their reproductive allocation in response to local environmental conditions. In particular, males reduced their reproductive allocation in poor soils, whereas females increased theirs, especially when competing with another female rather than growing alone. Finally, males displayed smaller above-ground vegetative sizes than females, but neither nutrient availability nor competition had a strong independent effect on relative size disparities between the sexes.Conclusions Selection appears to favour plasticity in reproductive allocation in dioecious M. annua, thereby maintaining a relatively constant size hierarchy between sexual morphs. In common with other dioecious species, there seems to be little divergence in the niches occupied by males and females of M. annua.
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Theory states that genes on the sex chromosomes have stronger effects on sexual dimorphism than genes on the autosomes. Although empirical data are not necessarily consistent with this theory, this situation may prevail because the relative role of sex-linked and autosomally inherited genes on sexual dimorphism has rarely been evaluated. We estimated the quantitative genetics of three sexually dimorphic melanin-based traits in the barn owl (Tyto alba), in which females are on average darker reddish pheomelanic and display more and larger black eumelanic feather spots than males. The plumage traits with higher sex-linked inheritance showed lower heritability and genetic correlations, but contrary to prediction, these traits showed less pronounced sexual dimorphism. Strong offspring sexual dimorphism primarily resulted from daughters not expressing malelike melanin-based traits and from sons expressing femalelike traits to similar degrees as their sisters. We conclude that in the barn owl, polymorphism at autosomal genes rather than at sex-linked genes generate variation in sexual dimorphism in melanin-based traits.
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BACKGROUND: Years since onset of sexual intercourse (YSSI) is a rarely used variable when studying adolescents- sexual outcomes. The aim of this study is to evaluate the influence of YSSI on the adverse sexual outcomes of early sexual initiators. METHODS: Data were drawn from the 2002 Swiss Multicenter Adolescent Survey on Health database, a nationally representative cross-sectional survey including 7429 adolescents in post mandatory school aged 16-20 years. Only adolescents reporting sexual intercourse (SI) were included (N=4388; 45% females) and divided by age of onset of SI (early initiators, age<16: N=1469, 44% females; and late initiators, age≥16: N=2919, 46% females). Analyses were done separately by gender. Groups were compared for personal characteristics at the bivariate level. We analyzed three sexual outcomes (≥4 sexual partners, pregnancy and non-use of condom at last SI) controlling for all significant personal variables with two logistic regressions first using age, then YSSI as one of the confounding variables. Results are given as adjusted odds ratios (aOR) using lSI as the reference category. RESULTS: After adjusting for YSSI instead of age, negative sexual outcomes among early initiators were no longer significant, except for multiple sexual partners among females, although at a much lower level. Early initiators were less likely to report non-use of condom at last SI when adjusting for YSSI (females: aOR=0.59 [0.44-0.79]; p<0.001; males aOR=0.71 [0.50-1.00]; p=0.053). CONCLUSION: YSSI is an important explanatory variable when studying adolescents- sexuality and needs to be included in future research on adolescents- sexual health.
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Variants of the melanocortin-1 receptor (MC1R) gene result in abrupt, naturally selected colour morphs. These genetic variants may differentially affect sexual dimorphism if one morph is naturally selected in the two sexes but another morph is naturally or sexually selected only in one of the two sexes (e.g. to confer camouflage in reproductive females or confer mating advantage in males). Therefore, the balance between natural and sexual selections can differ between MC1R variants, as suggest studies showing interspecific correlations between sexual dimorphism and the rate of nonsynonymous vs. synonymous amino acid substitutions at the MC1R. Surprisingly, how MC1R is related to within-species sexual dimorphism, and thereby to sex-specific selection, has not yet been investigated. We tackled this issue in the barn owl (Tyto alba), a species showing pronounced variation in the degree of reddish pheomelanin-based coloration and in the number and size of black feather spots. We found that a valine (V)-to-isoleucine (I) substitution at position 126 explains up to 30% of the variation in the three melanin-based colour traits and in feather melanin content. Interestingly, MC1R genotypes also differed in the degree of sexual colour dimorphism, with individuals homozygous for the II MC1R variant being 2 times redder and 2.5 times less sexually dimorphic than homozygous individuals for the VV MC1R variant. These findings support that MC1R interacts with the expression of sexual dimorphism and suggest that a gene with major phenotypic effects and weakly influenced by variation in body condition can participate in sex-specific selection processes.
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This study examined the role of posttraumatic stress disorder (PTSD) symptoms of re-experience, avoidance, and hyperarousal in the relationship between different types of trauma and alcohol use disorders (AUD). We used data from 731 trauma-exposed individuals who participated in the first wave of the PsyCoLaus-study. Trauma characteristics were assessed relatively to the occurrence of lifetime PTSD symptoms and AUD. The results suggest that lifetime and childhood sexual abuse as well as overall childhood trauma were directly linked to AUD and PTSD symptoms, in particular to avoidance symptoms. From single symptom clusters PTSD avoidance was found to specifically mediate the trauma-AUD pathway. Both childhood and sexual trauma strongly contribute to the comorbidity of PTSD and AUD and avoidance-type symptoms appear to play a central role in maintaining this association. Hence, the alleviation of avoidance symptoms might be an important target for therapeutic intervention among victims of sexual abuse before specific addiction treatment is initiated.