The concept of fecundability derives its importance for the study of human fertility from the fact that it is one of the principal determinants of fertility and is a major standard by which the impact of fertility reg...The concept of fecundability derives its importance for the study of human fertility from the fact that it is one of the principal determinants of fertility and is a major standard by which the impact of fertility regulation can be assessed;very few attempts have been made in Bangladesh for estimating fecundability. This study attempts to evaluate the levels, patterns, and trends of fecundability and identify the factors affecting fecundability in Bangladesh based on national surveys of Bangladesh Demographic and Health Survey (BDHS) 2007-1994. Total 9703 ever married women are included in the bivariate and multivariate analyses which reveal that age at first birth, age at marriage and marital duration play an important role in influencing marriage to first birth interval positively and thus fecundability negatively. Although fecundability in Bangladesh showed an increasing trend, but it is very low compared to developed and developing countries.展开更多
The problem of sewage disposal has received great attention worldwide.The raw sewage contains a variety of high inorganic and organic matters that affect natural water environment.To mitigate such problem,sewage may b...The problem of sewage disposal has received great attention worldwide.The raw sewage contains a variety of high inorganic and organic matters that affect natural water environment.To mitigate such problem,sewage may be recycled through aquaculture practice.Sewage recycling in aquaculture enhances water productivity through nutrients input.Proper loading of sewage ensures viable aquaculture;otherwise,fish mortality occurs due to poor water quality.To optimize sewage application,two different experiments were conducted,each with four treatments.In both experiments,three fish species namely rohu(Labeo rohita Hamilton,1822),mrigal(Cirrhinus mrigala Hamilton,1822),and bata(Labeo bata Hamilton,1822)were tested in triplicate in FRP(Fibre-Reinforced Plastic)tanks.Different sewage concentrations(0,25%,50%and 75%)used in first experiment were prepared by mixing freshwater,showing Biochemical Oxygen Demand(BOD)2.0±0.4 mg/L,10.8±1.4 mg/L,19.6±1.5 mg/L and 41.6±2.58 mg/L,respectively.After 30 days rearing,results showed≥75%fish survival in sewage concentrations up to 50%with BOD level 19.6±1.5 mg/L.Less than 50%fish survived in 75%sewage concentration,with BOD level as 41.6±2.58 mg/L.The second experiment was conducted for 90 days considering 50%sewage concentration as basal dose with BOD level as 19.6 mg/L as an acceptable limit for fish survival.Split doses of sewage were applied in T_(1),T_(2) and T_(3) treatments fortnightly,weekly and semi-weekly intervals,while single dose was used in C(control)treatment.Application of split doses resulted better hydro-biological changes,including nutrients recovery,in T_(1),T_(2) and T_(3) than that of single dose in control.Fish growth plotted with net primary productivity(NPP),phytoplankton and zooplankton densities exhibited positive correlations in T_(2)(12 doses)and T_(3)(24 doses),considered as optimal doses to ensure better water productivity for desirable fish production than sewage with single dose or limited doses(6 doses).展开更多
文摘The concept of fecundability derives its importance for the study of human fertility from the fact that it is one of the principal determinants of fertility and is a major standard by which the impact of fertility regulation can be assessed;very few attempts have been made in Bangladesh for estimating fecundability. This study attempts to evaluate the levels, patterns, and trends of fecundability and identify the factors affecting fecundability in Bangladesh based on national surveys of Bangladesh Demographic and Health Survey (BDHS) 2007-1994. Total 9703 ever married women are included in the bivariate and multivariate analyses which reveal that age at first birth, age at marriage and marital duration play an important role in influencing marriage to first birth interval positively and thus fecundability negatively. Although fecundability in Bangladesh showed an increasing trend, but it is very low compared to developed and developing countries.
文摘The problem of sewage disposal has received great attention worldwide.The raw sewage contains a variety of high inorganic and organic matters that affect natural water environment.To mitigate such problem,sewage may be recycled through aquaculture practice.Sewage recycling in aquaculture enhances water productivity through nutrients input.Proper loading of sewage ensures viable aquaculture;otherwise,fish mortality occurs due to poor water quality.To optimize sewage application,two different experiments were conducted,each with four treatments.In both experiments,three fish species namely rohu(Labeo rohita Hamilton,1822),mrigal(Cirrhinus mrigala Hamilton,1822),and bata(Labeo bata Hamilton,1822)were tested in triplicate in FRP(Fibre-Reinforced Plastic)tanks.Different sewage concentrations(0,25%,50%and 75%)used in first experiment were prepared by mixing freshwater,showing Biochemical Oxygen Demand(BOD)2.0±0.4 mg/L,10.8±1.4 mg/L,19.6±1.5 mg/L and 41.6±2.58 mg/L,respectively.After 30 days rearing,results showed≥75%fish survival in sewage concentrations up to 50%with BOD level 19.6±1.5 mg/L.Less than 50%fish survived in 75%sewage concentration,with BOD level as 41.6±2.58 mg/L.The second experiment was conducted for 90 days considering 50%sewage concentration as basal dose with BOD level as 19.6 mg/L as an acceptable limit for fish survival.Split doses of sewage were applied in T_(1),T_(2) and T_(3) treatments fortnightly,weekly and semi-weekly intervals,while single dose was used in C(control)treatment.Application of split doses resulted better hydro-biological changes,including nutrients recovery,in T_(1),T_(2) and T_(3) than that of single dose in control.Fish growth plotted with net primary productivity(NPP),phytoplankton and zooplankton densities exhibited positive correlations in T_(2)(12 doses)and T_(3)(24 doses),considered as optimal doses to ensure better water productivity for desirable fish production than sewage with single dose or limited doses(6 doses).
