When resources are scarce, female mammals should face a trade-off between lactation and other life-history traits such as growth, survival and subsequent reproduction. Kangaroos are ideal to test predictions about reproductive costs because they may simultaneously lactate and carry a young, and have indeterminate growth and a long breeding season. An earlier study in three of our five study pop...

Life history is an important framework for understanding many aspects of ontogeny and reproduction relative to fitness outcomes. Because growth is a key influence on the timing of reproductive maturity and age at first birth is a critical demographic variable predicting lifetime fertility, it raises questions about the synchrony of growth and reproductive strategies. Among the Pumé, a group of ...

In order to investigate drought stress and plant density the yield, yield components and protein of spotted bean grain (cultivar Talash), an experiment was carried out as split plots in randomized complete blocks with three replications in Yasouj, in 2012. Factors of the test including irrigation in three levels; without stress (control treatment), water stress in vegetative stage (interrupting...

background : the study of reproductive behaviors is one of the important factors of population. it plays a pivotal role in the growth of population.  reproductive behaviors are influenced by the cultural values and traditional beliefs of individuals. the aim of the present study is to compare reproductive behaviors of nomadic and non-nomadic tribes in the semirom province, and determine factors...

It is widely acknowledged that allopolyploidy via hybridization and genome doubling can easily lead to speciation, as polyploid hybrids can be immediately isolated from diploid parental taxa due to high levels of sterility caused by uneven numbers of chromosome complements in their progeny (Soltis and Soltis, 2009; Abbott et al., 2013). However, homoploid hybrid speciation (HHS), in which a hyb...

OBJECTIVE To determine follicular-fluid neurotrophin levels in women undergoing assisted reproductive techniques for different etiologies of infertility. DESIGN Prospective observational study. SETTING Academically affiliated assisted reproductive techniques unit. PATIENT(S) One hundred six patients undergoing an IVF cycle for different etiologies of infertility. INTERVENTION(S) Assessm...

Background and objectives: Life history theory predicts a shift in energy allocation from growth to reproductive function as a consequence of puberty. During adolescence, linear growth tapers off and, in females, ovarian steroid production increases. In this model, acquisition of lean mass is associated with growth while investment in adiposity is associated with reproduction. This study examin...