the effect of a commercial probiotic (protexin) on growth performance and survival rate in sobaity sparidentex hasta was investigated. 240 fish with average weight of 2.99±0.87g were treated for 10 weeks. this study was carried out in a completely random design with 12 experimental groups, in 4 treatments each with 3 replicates. experimental groups were consisted of four levels of 0.0, 0.5, 1.0...

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...

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...

a trend of significant increase in municipal solid waste generation has been recorded worldwide. this has been found due to over population growth rate, industrialization, urbanization and economic growth. consumerism speed has been found very high covering around more then 50% of total population since last decade due to higher economic growth, which has ultimately resulted in increased solid ...

the experiment was conducted to determine the effects of different photoperiods and darkness on the growth and survival of juvenile catla catla in the laboratory for 90 days. fishes were divided into four aquaria (10 fish per aquarium), and subjected to different photoperiod regimes of 8 hours light: 16 hours dark (8l:16d), 16 hours light: 8 hours dark (16l:8d), continuous light (24l:0d) and co...

"The population of China is still growing despite a dramatic decline in fertility in the past two decades. There are marked urban-rural differentials in fertility and, as a result, the pace of urbanization has significant effects on population growth. In this research an attempt is made to model urban-rural population growth in China. A demoeconomic model of urban and rural sectors is calibrate...

China has been an overachiever in the global process of demographic transition in the second half of the twentieth century. its mortality decline was unparalleled in human history among populations of significant size, consequently setting the stage for rapid population growth. in turn, rapid population growth laid the foundation for an unprecedented state intervention in birth control. China’s...

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...