145 research outputs found

    Mating skew in Barbary macaque males: the role of female mating synchrony, female behavior, and male–male coalitions

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    A fundamental question of sexual selection theory concerns the causes and consequences of reproductive skew among males. The priority of access (PoA) model (Altmann, Ann NY Acad Sci 102:338–435, 1962) has been the most influential framework in primates living in permanent, mixed-sex groups, but to date it has only been tested with the appropriate data on female synchrony in a handful of species. In this paper, we used mating data from one large semi-free ranging group of Barbary macaques: (1) to provide the first test of the priority-of-access model in this species, using mating data from 11 sexually active females (including six females that were implanted with a hormonal contraceptive but who showed levels of sexual activity comparable to those of naturally cycling females) and (2) to determine the proximate mechanism(s) underlying male mating skew. Our results show that the fit of the observed distribution of matings with sexually attractive females to predictions of the PoA model was poor, with lower-ranking males mating more than expected. While our work confirms that female mating synchrony sets an upper limit to monopolization by high-ranking individuals, other factors are also important. Coalitionary activity was the main tactic used by males to lower mating skew in the study group. Coalitions were expressed in a strongly age-related fashion and allowed subordinate, post-prime males to increase their mating success by targeting more dominant, prime males. Conversely, females, while mating promiscuously with several males during a given mating cycle, were more likely to initiate their consortships with prime males, thus reducing the overall effectiveness of coalitions. We conclude that high-ranking Barbary macaque males have a limited ability to monopolize mating access, leading to a modest mating skew among them

    Contraceptive use among HIV-infected women and men receiving antiretroviral therapy in Lusaka, Zambia: a cross-sectional survey

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    Abstract Background Family planning (FP) is an essential health service and an important part of comprehensive HIV care. However, there is limited information about the contraceptive needs of people living with HIV in sub-Saharan Africa, which in turn has hampered efforts to expand and integrate FP services into existing HIV programs. Methods We performed a cross-sectional survey to determine FP prevalence and predictors among HIV-positive women and men attending 18 public antiretroviral therapy (ART) clinics in Lusaka, Zambia. Trained peer counselors administered the 10-question survey to those seeking care for five days at each of the target sites. Results From February to April 2014, we surveyed 7,046 HIV-infected patients receiving routine HIV services. Use of modern contraception was reported by 69 % of female ART patients and 79 % of male ART patients. However, highly effective contraceptive use and dual method use were low among women (38 and 25 %, respectively) and men (19 and 14 %, respectively). HIV disclosure status (adjusted odds ratio (AOR) = 4.91, 95 % confidence interval (CI) = 3.32–7.24 for women, AOR = 3.58, 95 % CI = 2.39–5.38 for men) and sexual activity in the last 6 months (AOR = 5.80, 95 % CI = 4.51–7.47 for women, AOR = 6.24, 95 % CI = 3.51–11.08 for men) were associated with modern contraceptive use in multivariable regression. Most respondents said they would access FP services if made available within ART clinic. Conclusions While FP-ART integration may be a promising strategy for increasing FP service uptake, such services must focus on assessing sexual activity and advocating for dual method use to increase effective contraceptive use and prevent unintended pregnancies

    State-of-the-art of non-hormonal methods of contraception: I. Mechanical barrier contraception

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    Mechanical barriers, specifically male condoms, command renewed interest and are used today by more people. The worldwide prevalence rate of male condoms was about 6% in 2007 corresponding to 65 million cohabiting couples. The prevalence of female barrier methods, including diaphragms, cervical caps and female condoms has declined to less than 1% of women in North America and in north-west Europe. Even smaller percentages use female barriers elsewhere. First-year life table pregnancy probabilities of mechanical barrier methods range from 4 to 19 per hundred in clinical trials. The male condom is the only proved preventive tool against several sexually transmitted infections (STIs), especially HIV. The effectiveness of the diaphragm and cervical caps in this regard appears limited. Further research is needed to measure the efficacy of female condoms in disease prevention. Sponges are not known to protect against STIs. Because of their ease of use and availability, low short-term costs, relative freedom from side effects, and usefulness in combating STIs, mechanical barrier methods, especially condoms, will continue to be used on a large scale. For our literature search we used personal files, search engines such as Popline, Medline, PubMed and Google, and data bases of WHO, FHI and Cochrane Library

    State-of-the-art of non-hormonal methods of contraception: III. Intrauterine devices

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    Since the 1959 revival of the IUD, non-hormonal devices have become the most widely used of all reversible contraceptives. Pregnancy rates of copper-releasing IUDs in current use range from approximately 0.5 to 1.5 per hundred continuing users in the first year, with somewhat lower annual pregnancy rates thereafter. Evidence-based research has been systematically conducted and translated into guidelines for eligibility criteria and problem management. Recent device research, beyond the T, Multiload and frameless devices has centred on improved designs such as U ,Y and Slimline shapes, or enhanced copper release, the latter through electrochemical effects or nanotechnology applications. Other IUD research foci concern devices that decrease bleeding and pain by releasing non-steroidal anti-inflammatory drugs. Yet other research lines indicate noncontraceptive benefits of copper intrauterine devices in protecting against endometrial cancer, and favourable risk-benefit analyses of IUD use by women at risk of or post HIV infection. IUD mechanisms of action and the relation of IUDs to pelvic infection and ectopic pregnancy are briefly reviewed. For our literature search we used Medline, Popline and Cochrane Library data bases, Google search, our personal files, and the references contained in articles in our files
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