Manjurul Karim

The evolution of aquatic agricultural systems in Southwest Bangladesh in response to salinity and other drivers of change

Aquatic agricultural systems (AAS) in coastal Southwest Bangladesh have evolved in response to a number of stimuli and constraints including improving market access, technological change, and salinization. Farming systems in the region are highly dynamic, and are characterized by the integration of varying combinations of freshwater prawns, rice, fish, vegetables, and brackish water shrimp. This paper examines the developmental history, productivity, and profitability of three distinct AAS: a low-salinity freshwater prawn-dominated system; an intermediate-salinity-mixed prawn and shrimp system, and a high-salinity shrimp-dominated system. Productivity, cropping intensity, and profitability are found to be highest in the diversified low- and intermediate-salinity systems, and lower in the high-salinity system, where cultivation of rice and vegetables is no longer possible. The paper concludes that more diverse integrated systems reduce risk and vulnerability for farming households. Salinization is found to be a double-edged sword – proving a stimulus to diversification at low levels, but reducing agro-biodiversity at higher salt concentrations. While the adaptation strategies in all systems have been successful in maintaining or improving most, though not all, system functions due to high levels of social resilience, support for effective community-based adaptation strategies will enable continued transformation and adaptation to future drivers of change.

A Physically Based Accurate Model for Quantum Mechanical Correction to the Surface Potential of Nanoscale MOSFETs

We present a physically based explicit analytical model for the quantum mechanical (QM) correction to the surface potential of nanoscale metal-oxide-semiconductor (MOS) devices. The effect of wave function penetration into the gate dielectric is taken into account. Instead of using the band-gap widening approach, which indirectly includes QM correction, the proposed correction term is directly added to the semiclassical surface potential. Under accumulation bias, charges in extended states and quantized states contribute to the surface potential in different ways. The proposed QM correction considers this difference in contributions. Comparison with two existing analytical QM correction models and two self-consistent QM numerical models show that the proposed correction is more accurate than the existing analytical models. The improvement achieved under the accumulation bias is particularly significant. The gate C-V characteristics of a number of different MOS devices have been simulated using the proposed correction. Excellent agreement with published experimental data has been observed.

Fish and Meat Are Often Withheld From the Diets of Infants 6 to 12 Months in Fish-Farming Households in Rural Bangladesh:

Background: Fish is a widely available animal-source food in Bangladesh and a rich source of nutrients, yet little is known about practices related to incorporating fish into the diets of infants and young children. Objective: Use dietary diversity data to explore consumption patterns of fish and high-quality food items within the household and examine factors associated with delayed introduction of fish to infants and young children. Methods: Cross-sectional survey of 496 households with children <36 months participating in the Aquaculture for Income and Nutrition project in Bangladesh. Data collected included household characteristics, women’s dietary diversity score, and minimum dietary diversity score along with data on Infant and Young Child Feeding practices. Results: Most children (63.4%) met the threshold for minimum dietary diversity. Despite having received extensive nutrition education related to including fish in complementary foods, only half of the caretakers introduced fish at 6 months and the mean age of introduction of small fish was 8.7 months. Meat and fish were not common in infant diets but increased with child age. Concerns about bones were a major barrier to incorporating fish into infant diets. Conclusion: Given its nutrient profile and widespread availability in certain contexts, fish could be an underutilized opportunity to improve nutrition and health outcomes of infants and young children. Further research, including utilizing food processing technologies, is needed to develop appropriate responses to overcome these barriers.

Balancing between livelihood and biodiversity conservation: a model study on gear selectivity for harvesting small indigenous fishes in southern Bangladesh

AbstractThis study has determined a suitable mesh size for small indigenous fish species (SIS) harvesting and has also developed a new gill net operation technique taking into consideration of aqua...

Homestead pond polyculture can improve access to nutritious small fish

In Bangladesh, homestead pond aquaculture currently comprises a polyculture of large fish species but provides an ideal environment to integrate a range of small fish species. Small fish consumed whole, with bones, head and eyes, are rich in micronutrients and are an integral part of diets, particularly for the poor. Results from three large projects demonstrate that the small fish, mola (Amblypharyngodon mola) contributes significantly to the micronutrients produced from all fish, in homestead ponds, in one production cycle. Mola contributed 98%, 56% and 35% of the total vitamin A, iron and zinc produced, respectively, despite comprising only 15% of the total fish production by weight. If consumed within the household, mola could contribute half of the vitamin A and a quarter of the iron intake recommended for a family of four, annually. Homestead ponds are uniquely accessible to women who prepare the household food. Further dissemination of the carp-small fish technology provides opportunities to target women and men together for training on fish production and consumption, nutrition and gender equity. Women only training is also recommended to enable them to engage fully, without feeling dominated by men. Partnering with the fisheries and health sectors will encourage sustainable uptake of this promising technology. Clearly, dissemination could have significant health benefits; however, improved monitoring and evaluation, particularly of dietary diversity and diet quality are essential. Research priorities should also include the production techniques of other small indigenous fish species (SIS), besides mola, and the power dynamics between women and men in operating homestead ponds.