The Toba represent one of the many indigenous groups inhabiting the Gran Chaco of South America. They currently live in communities with different degrees of acculturation. We present here a preliminary data on fecundity and mortality estimates for a rural Toba population located in the province of Formosa, Argentina. Reproductive histories (n = 435) were obtained from villagers 12 years old an...

We explore the idea that a sensitivity analysis conducted on stage-specific demographic rates can be used to improve our ability to determine the efficacy of conservation plans that are designed to enhance the recovery of individual marine species. Because a given reserve may not be able to protect all life stages and habitats for wide-ranging marine organisms, reserves should target life histo...

this experiment was conducted to evaluate the effects of salt stress on some agro-physiological traits in ten varieties of bread (triticum aestivum l.) and durum (triticum turgidum l.) wheats in seedling stage. a greenhouse experiment was carried out as a split plot experiment based on a completely randomized design with four replications in hydroponic condition. different agronomic and physiol...

one may find out the application‎ ‎of mathematics in the areas of ecology‎, ‎biology‎, ‎environmental‎ ‎sciences etc‎. ‎mathematics is particulary used in the problem of‎ ‎predator-prey known as lotka-volterra predator-prey equations.‎ ‎indeed‎, ‎differential equations is employed very much in many areas‎ ‎of other sciences‎. ‎however‎, ‎most of natural problems involve some‎ ‎unknown functions...

Kerala is well-known globally for the unprecedented fertility transition in the Indian subcontinent towards the end of the last century. The state has already reached below-replacement fertility level in the 1990s while the rest of India was experiencing high or mid-level fertility. With this backdrop, an attempt was made in this paper (a) to explore the plausible factors associated with sub-re...

Approximately half the world's population now has replacement-level fertility or below. The UK experience in accommodating to a changing dependency ratio provides some generalizable insights. A mechanistic approach assuming a fixed retirement age and a need to raise fertility or increase immigration in order to maintain pensions at a fixed proportion of the gross domestic product (GDP) is overs...

Demographic heterogeneity--variation among individuals in survival and reproduction--is ubiquitous in natural populations. Structured population models address heterogeneity due to age, size, or major developmental stages. However, other important sources of demographic heterogeneity, such as genetic variation, spatial heterogeneity in the environment, maternal effects, and differential exposur...

Given the relatively slow development and less adequate management of resources, rapid growth of population in Punjab is an issue of vital concern. Significant improvement in the standard of living of its inhabitants may remain just a vision unless population growth is controlled. At the present rates, Punjab would be unable to meet the needs of its population and find jobs for those completing...

Recently, commentators in several prominent U.S. publications have declared that the population explosion is over and concluded that population growth is no longer a serious policy issue. “The population boom is a bust,” declares one.2 One statistic commonly cited as evidence of this is the global decline in fertility rates (the number of children born per woman). It is true that fertility worl...

Population The population is estimated to be 4.45 million (1999). The natural population growth rate reached 3.4 per 1000 in 1997, a figure well above the average EU levels. The main reasons for this are migration and the rise in average life expectancy. Future trends point to a growing and aging population. Fertility rates stood at 1.8 in 1999, the highest figure within the Scandinavian countr...