137 resultados para Sexual selection in animals


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Although numerous studies have reported an association between substance use and sexual assault, little is known about the impact of sexual assault on male African American crack cocaine users. This study found that from a sample of 137 respondents from Houston, Texas, one-third reported having been sexually assaulted at least once during their lifetime. Respondents who reported sexual assault were using cocaine more often and were more likely to be physically dependent on drugs and to report greater numbers of physical health problems due to their drug use. However, no differences were identified in respect of reported mental health problems, or problems with family, friends or the workplace associated with drug use. The findings suggest further research as to the impact of sexual assault on male crack cocaine users is warranted and that clinical staff working with male substance users require some awareness of the impacts of sexual assault.

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The transformation texture of α/β brass with a diffusional Widmanstätten α growth morphology has been investigated. Electron micrographs and electron backscattered diffraction was used to determine that the orientation relationship between the β phase and the α associated with nucleation at β grain boundaries was (44.3°) left angle bracket1 1 6right-pointing angle bracket. Crystallographic variant selection was observed across those prior β/β grain boundaries, but this has little effect on the transformation texture due to the crystal symmetry. The effect of the crystallographic variant selection on texture is further weakened by nucleation of diffusional transformed α in the grain interior.

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Transformation textures in the two-phase alloy Ti–6Al–4V have been studied. Samples were heated into the fully β phase condition and then slow cooled to allow diffusional transformation to α. This produced a microstructure of grain boundary α encircling colonies of Widmanstätten α. Electron backscattered diffraction (EBSD) texture measurements showed that the α texture was markedly sharper than that calculated on a basis of equal variant probability, indicating that significant variant selection was occurring during diffusional transformation. Investigation of the α variants produced across prior β grain boundaries has shown that the selection of variants during transformation is highly dependant on the crystallography of those boundaries. The effect of this crystallographic variant selection on the transformation texture has been modelled.

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Life-cycle assessment (LCA) is a method for evaluating the environmental impacts of products holistically, including direct and supply chain impacts. The current LCA methodologies and the standards by the International Organization for Standardization (ISO) impose practical difficulties for drawing system boundaries; decisions on inclusion or exclusion of processes in an analysis (the cutoff criteria) are typically not made on a scientific basis. In particular, the requirement of deciding which processes could be excluded from the inventory can be rather difficult to meet because many excluded processes have often never been assessed by the practitioner, and therefore, their negligibility cannot be guaranteed. LCA studies utilizing economic input−output analysis have shown that, in practice, excluded processes can contribute as much to the product system under study as included processes; thus, the subjective determination of the system boundary may lead to invalid results. System boundaries in LCA are discussed herein with particular attention to outlining hybrid approaches as methods for resolving the boundary selection problem in LCA. An input−output model can be used to describe at least a part of a product system, and an ISO-compatible system boundary selection procedure can be designed by applying hybrid input−output-assisted approaches. There are several hybrid input−output analysis-based LCA methods that can be implemented in practice for broadening system boundary and also for ISO compliance.

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In epidemiologic studies, researchers often need to establish a nonlinear exposure-response relation between a continuous risk factor and a health outcome. Furthermore, periodic interviews are often conducted to take repeated measurements from an individual. The authors proposed to use fractional polynomial models to jointly analyze the effects of 2 continuous risk factors on a health outcome. This method was applied to an analysis of the effects of age and cumulative fluoride exposure on forced vital capacity in a longitudinal study of lung function carried out among aluminum workers in Australia (1995-2003). Generalized estimating equations and the quasi-likelihood under the independence model criterion were used. The authors found that the second-degree fractional polynomial models for age and fluoride fitted the data best. The best model for age was robust across different models for fluoride, and the best model for fluoride was also robust. No evidence was found to suggest that the effects of smoking and cumulative fluoride exposure on change in forced vital capacity over time were significant. The trend 1 model, which included the unexposed persons in the analysis of trend in forced vital capacity over tertiles of fluoride exposure, did not fit the data well, and caution should be exercised when this method is used.

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The article analyzes the presentation of youth in the film "Lawn Dogs," directed by John Duigan. In the film, the child as victim is defined by socio-economic contexts. The author explores the discursive moves by which means the film witnesses or occludes the traumatic experiences suffered by the child and adolescent characters, and how far it articulates a satiric revision of social hierarchies that construct generational identities of gender and class.

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Bird assemblages in woodlands of southern Australia are characterised by a high proportion of ground-foraging species, many of which are experiencing population declines. We examined the foraging sites of 13 species of ground-foraging birds, including four common species and nine declining species, in four study areas representing different woodland types. Microhabitat features were recorded within a 3-m radius of observed foraging points and compared with random points. Significant differences between foraging and random plots were detected for all but one species, clearly indicating selection for foraging habitat. However, levels of dissimilarity between foraging and random plots were low, suggesting that much of the woodland study area is suitable for foraging. Microhabitat features of particular importance for multiple species were a low density of trees and shrubs, a high cover of native herbs, and fallen timber on the ground. Sites amidst dense trees tended not to be used. Several species had more particular requirements, such as the Diamond Firetail (Stagonopleura guttata) for grass cover and the White-winged Chough (Corcorax melanorhamphos) for litter cover. There was no evidence that declining species showed a greater degree of selection or were more restricted in the availability of foraging microhabitats than common species. Several of the key attributes of preferred foraging sites, such as tree density, can be actively managed at the local scale. A heterogeneous ground layer is needed to provide suitable foraging habitat for the full suite of ground-foraging birds. Achieving suitable heterogeneity in present-day woodlands will require careful and active management of various disturbance processes.

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A growing research base supports the predictive validity of actuarial methods of risk assessment with sexual offenders. These methods use clearly defined variables with demonstrated empirical association with re-offending. The advantages of actuarial measures for screening large numbers of offenders quickly and economically are further enhanced when the variables used can be extracted from existing electronic databases. This study reports the results of applying a computerized set of historical variables with a sample of 1,133 male sexual offenders released from prison by the New Zealand Department of Corrections. Area under the curve figures of 0.70-0.78 were obtained over periods of 5 to 15 years, reflecting a significant level of association with sexual recidivism. Detected rates of re-offending across risk levels were comparable to those previously reported for the Static-99. Rates of sexual re-offending by child molesters for all sexual offences and offences against child victims are reported separately.

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Australia and New Zealand have joined the movement of many Western societies in recent years to address a perceived gap in public safety by passing legislation allowing for extended supervision of sex offenders in the community after their release from prison. The Australian State of Victoria passed a law similar to that of New Zealand, and both laws have now been in effect for a similar period of time. Yet despite having comparable laws and approximately comparable base populations, there have been 145 extended supervision orders imposed in New Zealand and 20 such orders in Victoria. This article examines the differences in implementation and the underlying procedures used in the two jurisdictions to understand these very different outcomes. Implications for professional practice, ethics, public safety, and policy development are discussed.

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This article focuses on the challenge of dealing with allegations of child sexual abuse in the context of the Family Court of Australia. Of all cases that come before the Court, those involving such allegations are relatively uncommon. they tend to be the most difficult cases, however, and are more likely to require a trial and the involvement of qualified practitioners. The review establishes that parental separation is a special circumstance in which sexual abuse may be more likely to occur, and many allegations of sexual abuse are found to be true. There is evidence, however, that a proportion of allegations made by people other than the child concerned may be false. Whether these false allegations are well intentioned and genuinely believed, or maliciously motivated has been a contentious issue. Issues considered include the mishandling of cases, the failure by professionals to consider equally plausible alternative hypotheses than the sexual abuse of a child, confirmation bias, and the profound repercussions of allegations for all members of the family. It is concluded that all allegations of child sexual abuse must be evaluated in a thorough and sensitive manner to separate the few false allegations from the many that are true.

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Vertebrates respond to environmental stressors through the neuro-endocrine stress response, which involves the production of glucocorticoids. We have selected independent, duplicate divergent lines of zebra finches for high, low and control corticosterone responses to a mild stressor. This experiment has shown that over the first four generations, the high lines have demonstrated a significant realized heritability of about 20%. However, the low lines have apparently not changed significantly from controls. This asymmetry in response is potentially because of the fact that all birds appear to be showing increased adaptation to the environment in which they are housed, with significant declines in corticosterone response in control lines as well as low lines. Despite the existence of two- to threefold difference in mean corticosterone titre between high and low lines, there were no observed differences in testosterone titre in adult male birds from the different groups. In addition, there were no consistent, significant differences between the lines in any of the life history variables measured – number of eggs laid per clutch, number of clutches or broods produced per pair, number of fledglings produced per breeding attempt, nor in any of egg, nestling and fledgling mortality. These results highlight the fact that the mechanisms that underlie variation in the avian physiological system can be modified to respond to differences between environments through selection. This adds an additional level of flexibility to the avian physiological system, which will allow it to respond to environmental circumstances.

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Recent progress in techniques of quantifying between‐individual differences of color‐based ornaments has revealed undiscovered possibilities for research in sexual selection. We present how the color spectra data can be comprehensively used for studying the importance of sexual ornaments in the black grouse and how these ornaments are related to a male condition. For this, we used both correlative field and experimental data. Field data indicated that older males had more chromatic coloration than yearlings. Blue chroma of males was correlated with male mating success. We experimentally manipulated yearling birds with testosterone implants and found that testosterone‐implanted males had impaired expression of several sexual ornaments: 10 months after the implantation, both structural‐based blue and carotenoid‐based red eye comb coloration were diminished, as well as lyre (tail) length. However, the manipulation did not affect vital traits under natural selection (wing length or body mass). Our data indicate that structural color is an important trait in sexual selection in this lekking species. Importantly, the data also indicate that male sexual ornaments are more susceptible to environmental conditions than the other male traits, thus showing their heightened condition dependency compared with the other traits mediating the honesty of signaling.

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Women presenting with hirsuties/polycystic ovary syndrome have increased production of androgens. Clinical lore suggests that these women may have increased sexual desire. Treatment of hirsuties commonly involves antiandrogen therapy, a form of therapy with a potential for reducing sexual desire. The present study investigated sexual desire in 29 hirsute women aged 19 to 43 years presenting for therapy. We conducted a questionnaire appraisal of the women's sexual desire, body and self-esteem, and affect at baseline, 3 months, and 12 months and compared the data with a control group of 30 nonhirsute women of similar mean age. Those in the treatment group also had their Ferriman and Gallwey scores and body mass indices calculated at baseline and end of study for those in the treatment group. We determined hormone levels for those in the treatment group with baseline blood tests. Our hypotheses were that the hirsute women would experience different levels of sexual desire than the control group prior to therapy and that therapy would have a demonstrable effect on the self-reported sexual desire of these women. The study demonstrated that women with hirsuties had mean levels of sexual desire and body esteem that were significantly lower than the control group women. During the year-long course of therapy, the sexual desire levels of the hirsute women decreased progressively, while their self-esteem increased. The women's Ferriman and Gallwey scores fell, indicating diminishing hirsutism. These findings provide empirical data upon which clinicians can base advice to patients seeking therapy.