Trade Liberlisation as an Instrument for Regional Cooperation

Trade Liberlisation, Regional Co-operation

C/N-controlled periphyton-based freshwater prawn farming system: a sustainable approach to increase pond productivity

Three technologies showed to improve productivity and sustainability of pond production: (1) C/N ratio control, (2) providing substrates for periphyton development, and (3) fish driven re-suspension. The novelty of this PhD research is to combine these technologies, with the goal to raise pond productivity above levels obtained with each one of these technologies separately, and to increase the nutrient use efficiency in ponds above levels presently achieved, further enhancing sustainability. This combined technology is further referred to as C/N controlled periphyton (C/N-CP) technology. A series of experiments (Chapter 2-6) were conducted to develop such technology. The first step (Chapter 2) evaluated if increasing C/N ratio (from 10 to 20) in combination with providing vertical substrates for periphyton development in freshwater prawn monoculture ponds can enhance overall pond productivity. The results were encouraging due to the 75% increase of production; in addition it seemed that natural foods were underutilized by freshwater prawn. Therefore, the next step (Chapter 3) was further analysis of the above mentioned experiment investigating how C/N ratio control and addition of substrates influenced the natural food communities in freshwater monoculture ponds. This study suggested further investigation on the possibility of increasing stocking density of freshwater prawn and inclusion of tilapia due to its both sediment re-suspension and periphyton grazing activity. Therefore, in thethird step (Chapter 4) increasing stocking densities of prawn (from 2 to 3 m−2) and addition of different levels of tilapia (0, 0.5 and 1individual m−2) were tested. This study concludes that both stocking densities (2 and 3 juveniles m−2) of prawn with the addition of 0.5 tilapia m−2 resulted in higher fish production, good environmental condition and economic return. In the fourth step (Chapter 5), the effects of addition of periphyton substrates and tilapia driven bioturbation were tested in C/N controlled (C:N=20) system. This study showed that addition of tilapia (0.5 individual m−2) and periphytonsubstrates in C/N controlled ponds benefitedfreshwater prawn production and recommended that economicsustainability could still befurther enhanced by identifying cheaper on-farm carbohydratesources. Therefore, in the last step (Chapter 6) maize flour (Zea mays) is considered as a cheaper on-farm carbohydrate source and compared with tapioca starch. In addition, in this study considering the importance of rohu (Labeo rohita) as an indispensable species in south Asian aquaculture, both tilapia and rohu are considered to determine the suitability of either species in C/N-CP ponds. In added finfish (0.5 individual m−2),100% tilapia were found to be beneficial in C/N-controlled (C:N=20:1) prawn farming system compared to 50% tilapia+50% rohu or 100% rohu. In conclusion, a significant improvement of system environment, productivity and economic benefits was observed due to synergism among C:N ratio control, addition of periphyton substrates and tilapia driven bioturbation. Therefore, C/N-CP technology is a promising technology, improving the sustainability and productivity of present prawn farming by simple and affordable means.</p

Modelling and performance measure of a perinatal network centre in the United Kingdom

The main aim of this paper is to model the neonatal unit of a perinatal network centre using the general framework of a loss network model and to estimate some performance measures. A special case of the class of model has been applied for capacity planning to the perinatal network centre of a neonatal network in the United Kingdom. Using the data supplied from the perinatal network centre about admission process, length of stay (LoS) and discharge pattern of the babies, the loss network model is applied to estimate the admission refusal probability in the system under steady-state conditions. Results are derived for different arrival patterns and different combinations of cots at all levels of care of the neonatal unit. This approach can be useful to select the optimal combination of cots for any given acceptance rate of arrival to the neonatal unit

Knowledge on AIDS among female adolescents in Bangladesh: Evidence from the Bangladesh demographic and health survey data

To assess the knowledge on acquired immunodeficiency syndrome (AIDS) among female adolescents in Bangladesh, this study used data extracted from the Bangladesh Demographic and Health Survey (BDHS) 1996-1997. Of 1,446 ever-married women included in the study, most were currently married (96%), Muslims (92%) and from rural areas (91%). Only one in six adolescents had ever heard of AIDS. Of them, 57% reported AIDS as a fatal disease almost always, while only 22% believed that AIDS could be avoided. Multivariate analysis revealed that knowledge on AIDS was strongly and positively associated with education of female adolescents and their husbands and varied significantly across different parts of the country. Knowledge on AIDS was higher among relatively older and urban residents who had access to television or radio and whose husbands were using condom. Strong efforts are needed to improve awareness and to clarify misconceptions about AIDS. Improved access to education, mass-media, and promotion of condom use could prevent AIDS among female adolescents in Bangladesh

The Evolution of Dispersal Conditioned on Migration Status

We build on the work of El Mouden and Gardner (2008) and consider the evolution of natal dispersal conditioned upon an individual’s ‘migration status’. In particular, we look to compare the evolution of this kind of conditional dispersal with the evolution of its un­ conditional counterpart. Our goal is to determine the extent to which dispersal conditional upon migration status changes predictions about population-wide levels of dispersal. Sim­ ply we ask: what weight should the possibility of this kind of conditional dispersal be given by an evolutionary biologist? We find the stable dispersal rates of natives and non­ natives, respectively, are predicted to vary with changing parameter values, and the stable dispersal rates of natives and non-natives are predicted to differ from one another in a way consistent with inclusive-fitness theory. We also find differencs between Taylor’s (1988) unconditional dispersal rate, and the population-average dispersal rate predicted by our model

Effects of control of C/N ratio by low-cost carbohydrate addition on water quality and pond ecology in freshwater prawn Macrobrachium rosenbergii post-larvae nursing system

An experiment was conducted to evaluate the effects of control of carbon/nitrogen ratio (C/N ratio) by addition of low cost carbohydrate to the water column on water quality and pond ecology in freshwater prawn Macrobrachium rosenbergii post-larvae nursing system. In this experiment, two level of dietary protein 20% and 35% without carbohydrate addition (‘P20' and ‘P35') and with carbohydrate addition (‘P20+CH' and ‘P35+CH') were compared in small ponds of 40 m² area stocked with 20 post-larvae (0.021 ± 0.001g) per m² . Maize flour was used as low cost carbohydrate and applied to the water column followed by the first feeding during the day. The addition of carbohydrate significantly reduced (p0.05) of total phytoplankton and zooplankton among the treatments. Survival rate of prawn was significantly lowest (p0.05) was observed between P20+CH and P35 treatments. Control of C/N ratio by the addition of low-cost carbohydrate to the pond water column benefited the freshwater prawn nursing practices in three ways (1) increased heterotrophic bacterial growth supplying bacterial protein augment the prawn post-larvae growth performances, (2) reduced demand for supplemental feed protein and subsequent reduction in feed cost and (3) reduced toxic NH sub(3)-N and NO sub(2)-N levels in pond nursing system

Observation on some of the environmental parameters and feed quality of selected golda (Macrobrachium rosenbergii) farms in Bangladesh

A study was conducted to ascertain the existing farm water, effluent and feed quality of selected giant freshwater prawn farms from major prawn farming areas (Bagerhat Sadar, Noakhali Sadar and Mymensingh) of Bangladesh during July to November 2005. Water quality parameters such as the mean values of dissolved oxygen, alkalinity, nitrite-nitrogen, phosphate-phosphorus and ammoniacal nitrogen did not show any significantly differences among the farming areas. Whereas significant differences (p < 0.05) were observed in the mean values of temperature, secchi disc visibility, pH and chlorophyll a. However, all the water quality parameters in the farming areas were within the suitable range for prawn culture. There was no significant variation in nutrients concentration of discharged effluent among the prawn farming areas. All of the nutrients measured in effluent water were within the acceptable range and did not seem to pose a direct threat to the recipient environment. The analysed crude protein contents of commercial CP, Quality and Saudi-Bangla prawn feeds were 31.84%, 27.21% and 28.97%, respectively, whereas all analysed farm made feeds were less than 25%. The other nutrients of prawn feeds varied largely with the source of feeds and ingredients used to prepare feed. The annual yield of prawn varied from 320.4 to 512.6 kg/ha (mean 412.3 kg/ha) depending on the management system

Comparative performance of two extractants in colorimetric determination of soil organic matter in paddy soil

Commonly used soil organic carbon (SOC) determination methods are expensive, time consuming, require equipment and skilled personnel making them impractical to use at field level. Therefore, a laboratory analytical study was carried out to identify a suitable extractant for SOC extraction as part of an ongoing effort to develop a low cost quick method for determining soil organic matter (SOM) at field level. For this purpose, 38 soil samples were collected from different Agro Ecological Zone (AEZ) to represent typical rice based cropping pattern covering a sufficient range in texture, soil organic matter, pH, and type of management. Two extractants e.g. NaOH-Pyrophosphate + HCl and NaOH-EDTA were used to extract organic carbon from soil and two wavelength e.g. 300 and 400 nm were used to measure the absorbance of organic carbon in spectrophotometer. Soil organic carbon measurements by CNS analyzer were used as reference measurement to compare the extracting efficiency of SOC by the selected extractants. Both the extract and wavelength showed different degrees of error in OC measurement. The error sum square of NaOH-Pyrophosphate + HCl and NaOH-EDTA measured at 300 nm wavelength were 15.21 and 13.35 whereas at 400 nm it was 227.37 and 19.95, respectively. Consequently, the average error percentages at 300 nm were -33 and -8 while at 400 nm it was - 187 and -16. Based on the error sum square and error percentage, NaOH-Pyrophosphate + HCl performed better than the NaOH-EDTA, and 400 nm wavelength came out better than the 300 nm wavelength. In addition, both the extracts produced coloured solutions which were easily visible or detectable by naked eye and the colour intensity increased with the increase in SOC content. Variations in colour among the soils depending on organic matter content indicate that it would be possible to develop a new low cost method for SOM determination at field level by using NaOH-Pyrophosphate + HCl as the extractant. Further research is warranted to confirm this finding