In a variable yet predictable world, organisms may use environmental cues to make adaptive adjustments to their phenotype. Such phenotypic flexibility is expected commonly to evolve in life history traits, which are closely tied to Darwinian fitness. Yet adaptive life history flexibility remains poorly documented. Here we introduce the collembolan Folsomia candida, a soil-dweller, parthenogenet...

A woman's reproductive history influences her risk of breast cancer. The authors hypothesized that reproductive history also influences stage of disease at the time of diagnosis. The authors analyzed a population-based cohort of 1.5 million Danish women born between 1935 and 1978 for whom individual information on births was available. Between 1978 and 1994, 10,790 incident cases of breast canc...

Objective: To investigate the obstetric profile of women with tubal ligation and the existence of association with socio-demographic variables and sex. Methods: This is a quantitative and retrospective documentary study, developed in a Natural Birth Center in July 2008 in the city of Fortaleza-CE. The sample was composed by 277 medical records of patients who had tubal ligation. Results: There ...

The fact that reproductive factors have significant influence on the risk of breast cancer is well known. Early age of first full-term birth is highly protective against late-onset breast cancers, but each pregnancy, including the first one, increases the risk of early-onset breast cancer. Estradiol and progesterone induce receptor activator of NF-kappa B ligand (RANKL) in estrogen receptor (ER...

Alternative reproductive tactics (ARTs) coexisting within a population are found in many organisms. Their existence has been an enduring puzzle in evolutionary biology. Why should selection produce distinctly different alternatives to reach the same goal? How can such alternative solutions coexist in a population? What determines their evolutionary stability? Here we outline ultimate and proxim...

Recent theoretical work suggests that personality is a component of life history, but links between personality and either age-dependent reproductive success or life-history strategy are yet to be established. Using quantitative genetic analyses on a long-term pedigree we estimated indices of boldness and docility for 105 bighorn sheep rams (Ovis canadensis), born between 1983 and 1999, and com...

Background: Human Papilloma viruses (HPV) is the most common sexually transmitted infection (STI) and the most important pathogenic factor for cervical intraepithelial lesions and carcinoma therefore a significant source of morbidity and mortality worldwide. This study was designed to investigate reproductive and medical factors associated with HPV infection in women referred to Colposcopy clin...

Reproductive Health Arizona (RHAZ) is a project at Arizona State University. It records the history of reproductive health, medicine, and biology in Arizona. Arizona has a unique history with reproductive health, and that history influences the state today. Arizonans can use historical stories to inform their understanding of Arizona's present and future with reproductive health and medicine, a...

The study of post-reproductive lifespan has been of interest primarily with regard to the extended post-menopausal lifespan seen in humans. This unusual feature of human demography has been hypothesized to have evolved because of the "grandmother" effect, or the contributions that post-reproductive females make to the fitness of their children and grandchildren. While some correlative analyses ...