Respected editor 1 In his article Bellieni mentioned ‘in western countries couples have high expectative about the advantages of delayed parenthood and exploit fertility as late as possible’ (1). Decreasing total fertility rate (TFR) is the number of children who would be born per woman (or per 1,000 women) if she/they were to pass through the childbearing years bearing children according to a ...

BACKGROUND Fertility is one of the three principal components of population dynamics. High fertility and rapid population growth exert negative influences on economic and social development. This study was aimed to estimate the level and trends of fertility among (15-49 years) old women in kersa demographic surveillance and health research center, kersa district Eastern Ethiopia. METHODS The ...

Fertility is the major determinant of population growth rate. In the early 1960’s Pakistan was the pioneer country which focused on the family planning issues to control the fertility rate so that population growth would be controlled. But it has been observed that the population growth could not be controlled at the desired level yet. The main objective of this study is to explore the factors ...

the common green lacewing is an important natural enemy used for pest control in greenhouses. it is also very common in many agricultural systems. hence, studying lethal and sublethal effects of insecticides on this predator would be useful. toxicity of endosulfan, imidacloprid and indoxacarb was assessed on 1st instar larvae of chrysoperla carnea (stephens) in laboratory. residual bioassays we...

North and South Korea have both experienced demographic transition and fertility and mortality declines. The fertility declines came later in North Korea. In 1990, the population was 43.4 million in South Korea and 21.4 million in North Korea and the age and sex compositions were similar. This evolution of population structure occurred despite differences in political systems and fertility dete...

Some neo-Malthusians regard fertility as being kept in check by scarcities and constraints and, conversely, as being raised by economic prosperity. Since outmigration to developed countries and the receipt of food aid from developed countries relax the constraints imposed by a country’s carrying capacity, both will have a positive effect on fertility rates in developing countries. Moreover, bet...

A generalized Verhulst model subject to seasonal change in both fertility rate and carrying capacity is outlined. Numerical solutions to the Verhulst equations are employed to obtain optimal fertility rate phase shift with respect to carrying capacity. Possible natural selection for a preferred season of conception is investigated using agent based simulations. Both experiments indicate that sy...