137 resultados para Sexual selection in animals


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   Although there is an under-acknowledgement of the issue in Australia there is a large body of international scholarship on juveniles who exhibit sexually violent or coercive behaviours toward other juveniles. Research undertaken in the United States and the United Kingdom emphasises options for clinical treatment, the logistics of coordinating multi agency response, and the causes and correlatives for coercive sexual behaviours in adolescents. Much of this literature has tended to focus on adolescents and there is an urgent need for increased studies on young children engaging in problem sexual behaviour.

   The smaller body of work published in Australia also favours adolescents rather than children with much of this work heavily influenced by international clinical studies. There are, however, a handful of reports based on Australian practitioner data that do focus on young children who engage in problem sexual behaviour. This literature surveys and evaluates the very limited number of existing therapeutic programs in Australia, and provides interview data with practitioners working with children exhibiting problem sexual behaviour. In the main, this research reinforces the findings of the internationa scholarship, both in terms of the contributing factors to problem sexual activity in children, but also in terms of the need for multi-faceted and contextually based cognitive behavioural therapeutic programs in response. More importantly, this burgeoning field of study indicates how far we have to go both in understanding the extent of the problem in Australia and in fashioning appropriate programs for prevention and intervention. Dr Joe Tucci is Chief Executive Officer of the Australian Childhood Foundation (ACF), an organisation that has taken a lead in responding to childhood problem sexual behaviour. Tucci et al., (2006) claim an urgent need for investment in a dedicated research and response agenda (Staiger et al., 2005b). To effectively address this issue researchers and practitioners require comprehensive empirical data on problem sexual behaviour in children across all sectors of Australian society, including Indigenous communities.

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Previous studies have found both support and lack of support for a positive relationship between masculinity and symmetry, two putative signs of mate quality, in male faces. We re-examined this relationship using an explicit measure of facial fluctuating asymmetry, as well as other measures of asymmetry, and measures of facial masculinity/femininity. We also used ratings of these traits for faces. Further, we examined the relationship between facial sexual dimorphism and body asymmetry. We found no significant correlations between facial masculinity and any of our measures of asymmetry or ratings of symmetry in males. Facial femininity was not consistently associated with facial symmetry in females, but was associated with body symmetry. Therefore, for females, but not males, facial femininity and body symmetry may reflect similar aspects of mate quality. We also examined the relationships between trait ratings and measurements. Our results provide validation of our ability to measure aspects of asymmetry that are perceived to be symmetrical, and aspects of sexual dimorphism that are perceived as feminine in females and masculine in males.

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 Although population genetic theory is largely based on the premise that loci under study are selectively neutral, it has been acknowledged that the study of DNA sequence data under the influence of selection can be useful. In some circumstances, these loci show increased population differentiation and gene diversity. Highly polymorphic loci may be especially useful when studying populations having low levels of diversity overall, such as is often the case with threatened or newly established invasive populations. Using common starlings Sturnus vulgaris sampled from invasive Australian populations, we investigated sequence data of the dopamine receptor D4 gene (DRD4), a locus suspected to be under selection for novelty-seeking behaviour in a range of taxa including humans and passerine birds. We hypothesised that such behaviour may be advantageous when species encounter novel environments, such as during invasion. In addition to analyses to detect the presence of selection, we also estimated population differentiation and gene diversity using DRD4 data and compared these estimates to those from microsatellite and mitochondrial DNA sequence data, using the same individuals. We found little evidence for selection on DRD4 in starlings. However, we did find elevated levels of within-population gene diversity when compared to microsatellites and mitochondrial DNA sequence, as well as a greater degree of population differentiation. We suggest that sequence data from putatively nonneutral loci are a useful addition to studies of invasive populations, where low genetic variability is expected.

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PURPOSE: We sought to examine cancer diagnosis, cancer treatment, and related risk factors among Australian, middle-aged, exclusively heterosexual women compared with sexual minority women (SMW; mainly heterosexual, bisexual, mainly lesbian, and lesbian). METHODS: Secondary data analysis of the Australian Longitudinal Study of Women's Health for women born in 1946 through 1951 (n = 10,451) included bivariate tests (i.e., contingency table analyses, independent t tests). RESULTS: SMW did not have significantly higher cancer diagnoses compared with exclusively heterosexual women, although they were more likely to report never having had a mammogram or pap smear. SMW were also significantly more likely to be high-risk drinkers (11.1% vs. 6.8%; p < .05), current smokers (15.1% vs. 8.3%; p < .001), report significantly higher rates of depression (mean ± SD; 6.4 ± 5.5 vs. 5.4 ± 5.1; p < .01.), have experienced physical abuse (10.2% vs. 5.1%; p < .001), and been in a violent relationship (27.2% vs. 12.8%; p < .001). CONCLUSION: SMW had higher rates of several known cancer risk factors, ostensibly placing them at higher risk of cancer as well as chronic health conditions. Further research is needed to determine whether increased risk results in increased cancer as these women age, and to inform the development of interventions to reduce the risk of disease for SMW.

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The food resource hypothesis of breeding habitat selection in beach-nesting birds suggests that birds breed at sites with more prey to meet the increased energetic requirements associated with breeding. We compare prey resources using pitfall traps and core samples at breeding sites and absence sites of the eastern population of hooded plover, Thinornis rubricollis rubricollis, which, in this part of its range, is a threatened obligate beach bird. Breeding sites had higher abundances, equivalent species richness, and different assemblages of invertebrate prey compared with absence sites. Assemblages at breeding sites were characterised by more isopods, and fewer beetles of the family Phycosecidae. Breeding habitat selection by plovers appears to be associated with selection for sites with more food, and any process that degrades food resources at a site (e.g. kelp harvesting or marine pollution events) may reduce the likelihood of occupancy of that site by breeding birds.

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This study aimed to evaluate a scale to measure attitudes to child sexual abuse (CSA) in remote Australian Indigenous communities. The scale was developed to gauge attitudes that may be inhibiting the reporting of cases of CSA to police, as well as to evaluate whether interventions that focused on collaborative relationships between community members and police resulted in changes in attitudes. Participants included service providers living outside the community (58%), community members (living within the community; 9%), and service providers who were also community members (33%); 18% of participants identified as Indigenous. Principal components analysis revealed a nonintuitive six-factor solution that did not support the original four concepts. Four intuitive factors emerged from an abridged version of the scale: entrenched issues, personal understanding and knowledge, communication between community and government, and community action. The scale detected significant differences between community status and between Indigenous status groups on some factors.

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Glucocorticoids hormones (GCs) are intuitively important for mediation of age-dependent vertebrate life-history transitions through their effects on ontogeny alongside underpinning variation in life-history traits and trade-offs in vertebrates. These concepts largely derive from the ability of GCs to alter energy allocation, physiology and behaviour that influences key life-history traits involving age-specific life-history transitions, reproduction and survival. Studies across vertebrates have shown that the neuroendocrine stress axis plays a role in the developmental processes that lead up to age-specific early life-history transitions. While environmental sensitivity of the stress axis allows for it to modulate the timing of these transitions within species, little is known as to how variation in stress axis function has been adapted to produce interspecific variation in the timing of life-history transitions. Our assessment of the literature confirms that of previous reviews that there is only equivocal evidence for correlative or direct functional relationships between GCs and variation in reproduction and survival. We conclude that the relationships between GCs and life-history traits are complex and general patterns cannot be easily discerned with current research approaches and experimental designs. We identify several future research directions including: (i) integration of proximate and ultimate measures, including longitudinal studies that measure effects of GCs on more than one life-history trait or in multiple environmental contexts, to test explicit hypotheses about how GCs and life-history variation are related and (ii) the measurement of additional factors that modulate the effects of GCs on life-history traits (e.g. GC receptors and binding protein levels) to better infer neurendocrine stress axis actions. Conceptual models of HPA/I axis actions, such as allostatic load and reactive scope, to some extent explicitly predict the role of GCs in a life-history context, but are descriptive in nature. We propose that GC effects on life-history transitions, survival probabilities and fecundity can be modelled in existing quantitative demographic frameworks to improve our understanding of how GC variation influences life-history evolution and GC-mediated effects on population dynamics Lay Summary Functional Ecology

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For the successful prosecution of child sexual abuse offences, investigative interviews of alleged victims must establish beyond reasonable doubt the nature of each sexual offence alleged. One limitation of interviews from an evidential (prosecution) perspective is that they often include unnecessary questions about sexual acts, which risk damaging the witness's credibility in the eyes of the jury. The aim of this study, using focus group methodology, was to elicit further guidance from prosecutors about when, and how, interviewers should clarify details about sexual acts. Overall, the prosecutors advised that three factors need to be considered before asking clarifying questions: whether the detail already provided by the witness would be clear to juries; the developmental age of the child; and the strength of the evidence available to support the allegations. These findings and their implications for investigative interviewers are discussed.

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BACKGROUND: Taiwan has the highest incidence and prevalence of end-stage renal disease (ESRD) in the world with 55,499 ESRD patients on long-term dialysis. Nevertheless, 90.96% of these patients are managed on maintenance haemodialysis (HD), with only 9.03% enrolled in a peritoneal dialysis (PD) programme. AIM: The study aim was to identify the factors affecting Taiwanese patient's selection of PD in preference to HD for chronic kidney disease. METHODS: A cross-sectional research design was utilized with 130 chronic renal failure (CRF) patients purposively selected from outpatient nephrology clinics at four separate Taiwan hospitals. Logistic regression was used to identify the main factors affecting the patient's choice of dialysis type. RESULTS: Single-factor logistic regression found significant differences in opinion related to age, education level, occupation type, disease characteristics, lifestyle modifications, self-care ability, know-how of dialysis modality, security considerations and findings related to the decisions made by medical personnel (P < 0.05). Moreover, multinomial logistic regression after adjustment for interfering variables found that self-care ability and dialysis modality know-how were the two main factors affecting the person's selection of dialysis type. CONCLUSIONS: Self-care ability and the person's knowledge of the different types of dialysis modality and how they function were the major determinants for selection of dialysis type in Taiwan based on the results from this study. The results indicate that the education of CRF patients about the types of dialysis available is essential to enable them to understand the benefits or limitations of both types of dialysis.

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Objective: This study used matched samples from schools in the states of Victoria and Washington to compare sexual behaviour in early adolescence. It was hypothesised that the contrasting dominant policy objectives of harm minimisation in Australia and abstinence in the USA would result in state differences for markers of sexual risk, mirroring prior cross-national findings in substance use. Method: A two-stage cluster sampling approach was used to recruit students from the two states. Self-reported sexual behaviour was examined for 1,596 students in annual surveys from Grade 7 in 2002 to Grade 9 in 2004. Prevalence estimates were derived for each measure of sexual behaviour, and comparisons were made between gender groups in each state. Results: State differences were found for girls' first sex, with significantly more girls in Washington than Victoria having had sex by Grade 7. By Grade 9, significantly more girls in Victoria reported sex in the last year and more sexual partners than girls in Washington. A large proportion of Grade 9 students across both states reported inconsistent contraception use. Conclusions: Contradicting the abstinence policy objective, first sex by Grade 7 was more prevalent in Washington than in Victoria. While sexual behaviour was more prevalent in Grade 9 in Victoria, the sexually active showed no clear cross-national differences in markers of risk such as contraception use and pregnancy outcomes. Findings demonstrate few cross-national differences in adolescent sexual behaviour despite the different policy contexts of Victoria and Washington.