119 research outputs found
Study of the plasma immersion implantation of titanium in stainless steel
The results of the study of the pulsed plasma-immersion ion implantation of titanium in steel Cr18Ni10Ti depending on the time (dose) implantation are presented. It is shown that the change of the element and the phase composition of the surface layers and their microscopic characteristics and mechanical properties (hardness, wear resistance) depending on the implantation time is not monotonic, but follows to a certain rule. The possibility of interpretation of the obtained results in the thermal spike concept of the generation on the surface by the stable (magic) clusters is discussed. This concept follows logically from the recent studies on the plasma arc composition and from a polyatomic clusters-surface interaction
The Copper T 380 Intrauterine Device: A Summary of Scientific Data
Intrauterine devices are the most widely used of all reversible contraceptive methods worldwide. Modern IUDs are among the most effective and long-acting methods of family planning and are acceptable options for many women. This monograph presents highlights of the clinical performance of the Copper T 380 over eight years, including the latest data on effectiveness, expulsions, and continuation rates. It incorporates data from Population Council and World Health Organization studies, and work by scientists at Family Health International and in several countries. Clinical studies of the three models of the Copper T 380 have provided substantial evidence of the safety, effectiveness, convenience, acceptability, and long-acting quality of this IUD. The bulk of the material in this document presents preclinical and clinical performance, including mechanisms of action, effectiveness, outcome of accidental pregnancy, rates of expulsion and ectopic pregnancy, side effects, continuation rates, return to fertility, and lactation and IUD use. There is also discussion of the data on IUD use and pelvic inflammatory disease, and the importance of performing skilled insertions under aseptic conditions
Science Development
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68479/2/10.1177_107554708500600404.pd
Mating skew in Barbary macaque males: the role of female mating synchrony, female behavior, and male–male coalitions
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
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
- …