Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    The benefit of using an ensemble of seasonal streamflow forecasts in water allocation decisions
    Kaune, Alexander ; Chowdhury, Faysal ; Werner, Micha ; Bennett, James - \ 2020
    Hydrology and Earth System Sciences 24 (2020)7. - ISSN 1027-5606 - p. 3851 - 3870.

    The area to be cropped in irrigation districts needs to be planned according to the allocated water, which in turn is a function of the available water resource. Initially conservative estimates of future (in)flows in rivers and reservoirs may lead to unnecessary reduction of the water allocated. Though water allocations may be revised as the season progresses, inconsistency in allocation is undesirable to farmers as they may then not be able to use that water, leading to an opportunity cost in agricultural production. We assess the benefit of using reservoir inflow estimates derived from seasonal forecast datasets to improve water allocation decisions. A decision model is developed to emulate the feedback loop between simulated reservoir storage and water allocations to irrigated crops and is evaluated using inflow forecasts generated with the Forecast Guided Stochastic Scenarios (FoGSS) model, a 12-month ensemble streamflow forecasting system. Two forcings are used to generate the forecasts: ensemble streamflow prediction - ESP (historical rainfall) - and POAMA (calibrated rainfall forecasts from the POAMA climate prediction system). We evaluate the approach in the Murrumbidgee basin in Australia, comparing water allocations obtained with an expected reservoir inflow from FoGSS against the allocations obtained with the currently used conservative estimate based on climatology as well as against allocations obtained using observed inflows (perfect information). The inconsistency in allocated water is evaluated by determining the total changes in allocated water made every 15 d from the initial allocation at the start of the water year to the end of the irrigation season, including both downward and upward revisions of allocations. Results show that the inconsistency due to upward revisions in allocated water is lower when using the forecast datasets (POAMA and ESP) compared to the conservative inflow estimates (reference), which is beneficial to the planning of cropping areas by farmers. Overconfidence can, however, lead to an increase in undesirable downward revisions. This is more evident for dry years than for wet years. Over the 28 years for which allocation decisions are evaluated, we find that the accuracy of the available water estimates using the forecast ensemble improves progressively during the water year, especially 1.5 months before the start of the cropping season in November. This is significant as it provides farmers with additional time to make key decisions on planting. Our results show that seasonal streamflow forecasts can provide benefit in informing water allocation policies, particularly by earlier establishing final water allocations to farmers in the irrigation season. This allows them to plan better and use water allocated more efficiently.

    Techno-environmental analysis of battery storage for grid level energy services
    Chowdhury, Jahedul Islam ; Balta-Ozkan, Nazmiye ; Goglio, Pietro ; Hu, Yukun ; Varga, Liz ; McCabe, Leah - \ 2020
    Renewable and Sustainable Energy Reviews 131 (2020). - ISSN 1364-0321
    Battery energy storage system (BESS) - Combined cycle gas turbine (CCGT) - Energy system modelling - Life cycle assessment (LCA) - Renewable integration

    With more and more renewable energy sources (RES) going into power grids, the balancing of supply and demand during peak times will be a growing challenge due to the inherent intermittency and unpredictable nature of RES. Grid level batteries can store energy when there is excess generation from wind and solar and discharge it to meet variable peak demand that is traditionally supplied by combined cycle gas turbine (CCGT) plants. This paper assesses the potential of battery storage to replace CCGT in responding to variable peak demand for current and future energy scenarios (FES) in the UK from technical and environmental perspectives. Results from technical analysis show that batteries, assuming size is optimised for different supply and demand scenarios proposed by the National Grid, are able to supply 6.04%, 13.5% and 29.1% of the total variable peak demand in 2016, 2020 and 2035, respectively while CCGT plants supply the rest of the demand. Particularly, to phase out CCGT variable generation from the UK grid in 2035, electricity supply from wind and solar needs to increase by 1.33 times their predicted supply in National Grid's FES. The environmental implications of replacing CCGT by batteries are studied and compared through a simplified life cycle assessment (LCA). Results from LCA studies show that if batteries are used in place of CCGT, it can reduce up to 87% of greenhouse gas emissions and that is an estimated 1.98 MtCO2 eq. for an optimal supply, 29.1%, of variable peak demand in 2035.

    Salinity drives growth dynamics of the mangrove tree Sonneratia apetala Buch. -Ham. in the Sundarbans, Bangladesh
    Rahman, Md Saidur ; Sass-Klaassen, Ute ; Zuidema, Pieter A. ; Chowdhury, Md Qumruzzaman ; Beeckman, Hans - \ 2020
    Dendrochronologia 62 (2020). - ISSN 1125-7865
    Cambial activity - Dendrochronology - Growth ring - Sonneratia apetala - The Sundarbans

    Mangroves throughout the world are threatened by environmental changes apart from anthropogenic disturbances. Many of these changes may inhibit the growth and survival of mangrove species. To understand and predict the effects of global change on mangrove forests, it is necessary to obtain insights on the growth dynamics of mangroves in relation to environmental factors. This study was conducted on Sonneratia apetala, a mangrove species which grows under a range of salinity conditions across the Sundarbans in Bangladesh. We studied trees growing under respectively high, medium, and low salinity conditions based on the influence of freshwater discharge. First, the periodicity of radial growth across the year was detected by applying cambial analyses. Based on tree-ring analyses, we calculated the growth response of S. apetala to monthly variation in precipitation and temperature as well as river discharge, as a proxy for salinity. We found the cambium of S. apetala being active during the monsoon and post-monsoon period whereas it was dormant in the pre-monsoon. This periodicity in radial growth leads to the formation of distinct annual rings with ring boundaries being marked by radially flattened fibres. S. apetala trees growing under low salinity conditions generally show higher growth rates indicating the positive impact of river discharge, i.e. freshwater input on mangrove growth. Wet and warm conditions during the monsoon period positively affected S. apetala growth, especially in the low salinity zone. Our results show that salinity is the primary driver of growth dynamics of S. apetala in the Sundarbans. A gradual or seasonal increase in salinity, e.g. as a consequence of sea-level rise may therefore importantly alter the growth of this species, possibly leading to changes in mangrove forest dynamics and zonation.

    Do oyster breakwater reefs facilitate benthic and fish fauna in a dynamic subtropical environment?
    Chowdhury, Mohammed Shah Nawaz ; Shahadat Hossain, M. ; Ysebaert, Tom ; Smaal, Aad C. - \ 2020
    Ecological Engineering 142 (2020). - ISSN 0925-8574

    Oyster breakwater reefs used for coastal protection have shown to enhance local biodiversity. Particularly, macro-invertebrate and fish assemblages can benefit directly from reefs providing structurally complex habitats and indirectly through alteration of soft-sediment environment near the reef areas. To test this hypothesis, a manipulative field experiment was carried out on an eroding intertidal flat in the southeastern coast of Bangladesh by deploying replicate units of each 20 m long oyster breakwater reefs specially designed to protect adjacent shorelines. Transient fishes and resident intertidal macro-invertebrate communities were assessed monthly for a period of 18 months. On the intertidal flat, five transects were setup for faunal and environmental data collection, three crossing the breakwater reefs and two along the control areas without reefs. Prior to the deployment of the reefs, both the macro-invertebrate and fish assemblage were not significantly different among the five transects, indicating a rather uniform distribution of species in all tidal flats. Data collected post-reef deployment revealed that oyster breakwater reefs supported a greater biomass as well as abundance of benthic macro-invertebrates on the landward mudflat behind the reefs than the mudflat of control sites. The community structure, and seasonal variation of the macrobenthic community were associated with the variations in the sediment accumulation, as influenced by the breakwater reefs. Additionally, higher abundance of transient finfish and mobile macro-invertebrates at the reef sites suggest that the faunal communities were attracted by the higher abundance of prey resources (i.e. polychaetes, small crustaceans, juvenile gastropods and bivalves) as supported by the reefs. Thus, the reef areas served as shelter, nursery, and foraging grounds for different species. Though the ecological benefits of using oyster breakwater reefs only span adjacent to the reefs, this study confirms the importance of reef structure in facilitating local coastal biodiversity in a subtropical region.

    Ecological engineering with oysters for coastal resilience : Habitat suitability, bioenergetics, and ecosystem services
    Chowdhury, Mohammed Shah Nawaz - \ 2019
    Wageningen University. Promotor(en): A.C. Smaal; T. Ysebaert, co-promotor(en): S. Hossain. - Wageningen : Wageningen University - ISBN 9789463433938 - 193

    Ecosystem based coastal management has gained in interest over the last decades. Development was achieved by incorporating different ecosystems services into coastal protection that can deal with threats related to climate change, such as accelerating sea level rise and increased storminess. The ecosystem-based approach not only tries to minimize anthropogenic impacts of coastal protection infrastructures on ecosystems but also aims at offering possibilities to enhance ecosystem functioning and resilience. Natural coastal ecosystems, such as biogenic reefs, dunes, beaches and tidal wetlands have potential value in protecting the coast from erosion and waves, with the benefit that these systems have some ability to self-repair and adapt in changing climate. The use of sustainable ecosystems that integrate human society with its natural environment for the benefit of both is called ecological engineering. It attempts to combine engineering principles with ecological processes to reduce environmental impacts from built infrastructure. Certain key species inhabiting those coastal habitats are known as ecosystem engineers. A number of ecosystem engineers such as coral reefs, reef forming bivalves, vegetation of kelps and seagrasses, marshes and mangroves are known to play engineering roles in shallow estuarine and coastal areas.

    Reef forming bivalves that occur in coastal waters can attenuate erosive wave energies, stabilize sediments and reduce marsh retreat. Oysters are commonly said to be ecosystem engineers as they form structures that influence the environment around them in ways that are beneficial to other species. There is a positive feedback of oyster reefs on the settlement of new recruits which makes the reefs self-sustaining. They provide a variety of ecologically and economically valuable goods and services. Oyster reefs serve as natural coastal buffers, absorbing wave energy directed at shorelines and reducing erosion from boat wakes, sea level rise, and storms. Given adequate recruitment and survival, oyster reefs could be self-sustaining elements of coastal protection that enhance other habitats. More than fifty studies were conducted throughout the world since 1995 to evaluate the different ecosystem services provided by oyster reefs including coastal defence. Several studies showed that created oyster reefs can reduce the coastal erosion rate in comparison to control sites with no reefs. This PhD study utilized this concept of oysters as ecosystem engineers and studied the rock oyster, Saccostrea cucullata, in a subtropical, monsoon dominated environment in Bangladesh. This particular environment imposes dynamic conditions for oysters to grow and act as ecosystem engineers. This study investigated the critical factors that determine oyster (S. cucullata) growth and development in a dynamic, monsoon dominated coastal ecosystem of Bangladesh. This study performed experiments by using oyster breakwater reefs to evaluate their eco-engineering effect on: (1) erosion control; and (2) biodiversity of benthic macroinvertebrates and fishes. It was aimed that the application of oyster breakwater reefs can be beneficial to mitigate erosion of tidal flats, promote sediment accretion and facilitate habitats for increasing saltmarsh growth and faunal abundance.

    At first, the question was where oysters can settle and grow out, so the focus is on boundary conditions in terms of habitat quality (Chapter 2). To answer this, a habitat suitability index (HSI) model was developed to identify potential suitable sites around the south-eastern Bangladesh coast, where oysters can establish. Seven habitat factors were used as input variables for the HSI model: water temperature, salinity, dissolved oxygen, particulate inorganic matter (PIM), pH, Chlorophyll-a, and water flow velocity. Comprehensive field surveys were conducted at 80 locations to collect geo-spatial environmental data, which were used to determine HSI scores using habitat suitability functions. The model results clearly showed that sites from the mouth of Sangu River to the tip of Teknaf, including the offshore islands (Kutubdia and Maheshkhali), are found suitable (HSI >0.50) habitats for oysters, except a few areas near small river mouths which become dynamic with freshwater flashes during monsoon months. These areas showed relative high salinity, Chlorophyll-a, dissolved oxygen and pH. In contrast, freshwater dominated estuaries and nearby coastal areas (i.e. northern part of the study area coving Sandwip, Feni, Mirsarai, Chittagong) with high suspended sediment concentrations from river discharges were found less suitable (HSI <0.50) for oysters. Salinity, Chlorophyll-a, dissolved oxygen and pH were identified as driving factors that determine the habitat quality for oyster in Bangladesh coast. The HSI model results match the current distribution of oysters throughout the investigated area. The good correspondence with the field data enhances the reliability of the presented HSI model as an interactive and quantitative tool for planning and managing oyster resources along the south-eastern coast of Bangladesh.

    Secondly, seasonal dynamics in oyster performances are analysed by measurements of the physiological performance of the oysters as a function of environmental conditions (Chapter 3 and 4). Chapter 3 provides physiological information of S. cucullata related to different ecological parameters, which were synthesized from large number of eco-physiological experiments and the outcomes were further used to estimate the DEB model parameters. It is concluded that the hydrometeorological aspects, i.e. a monsoon regime and high turbidity levels, are quite different from temperate regions and drives the physiological traits of shellfish organisms in Bangladesh coastal waters. The estimated DEB parameters for Saccostrea cucullata and their related univariate data provided opportunities (see chapter 4) to simulate the oyster growth in a monsoon dominated hydrodynamic environment. Chapter 4 utilizes the dynamic energy budget (DEB) theory, which allows to establish links between the physiology of an organism and its environment by capturing the metabolic dynamics of an individual organism through its entire life cycle. Developed DEB model was validated by simulating S. cucullata growth under varying hydro-biological conditions. The model results are compared with independent field observations on the growth (length and weight) of S. cucullata at three different sites (Sonadia, Kutubdia and Inani) located in the south-eastern coast of Bangladesh, covering a distinct environmental gradient. The sites vary spatially and temporally in environmental conditions such as salinity, total particulate matter (TPM) and Chlorophyll-a concentrations due to the monsoonal river discharges. At the three sites, field observations of oyster growth, temperature and food availability (Chlorophyll-a and Particulate Organic Matter-POM) have been carried out in the period between September 2014 - August 2017. The DEB model reproduced temporal as well as spatial variation in oyster growth as a function of the prevailing environmental conditions. Growth rates of oysters were highest (shell length: 3cm yr-1) in Sonadia Island due to better food conditions. Whereas, the growth rates were relatively low (1.94 cm yr-1) in Kutubdia and none of oysters survived in Inani during the monsoon event due to high suspended load (889 ± 101 mg l-1) and low Chlorophyll-a (1.86 ± 0.16 µg l-1) conditions. Temporal variation is largely monsoon driven: the period between November to May was the main growing season for oysters along the Bangladesh coast, while growth slowed down in the monsoon months (June-September). DEB model simulations for S. cucullata showed good fit (>8.54 score out of 10) with measured growth data under the different in situ conditions throughout the seasons. It means that the DEB model for S. cucullata demonstrated accuracy for simulating growth in its natural environment along the Bay of Bengal. Therefore, the model can be used to evaluate potential sites for oyster culture development or restoration to enhance coastal resilience.

    Thirdly, in Chapters 5 and 6, it was tested if the application of oyster breakwater reefs contribute to reducing coastal erosion in the context of monsoon-dominated subtropical coast and at the same time be beneficial in facilitating other habitats (i.e. mudflat, saltmarsh) and species (macro-invertebrates, fishes). Therefore a suitable site was chosen based on model outputs and observations, namely an eroding mudflat on Kutubdia Island. Here, concrete rings with oysters overgrown for 2 years were placed as oyster breakwater reefs in the lower intertidal zone of the mudflat. The oyster breakwater reefs were tested to see whether it reduced sediment erosion, promoted mudflat stability and enhanced seaward salt marsh expansion and growth, in comparison with areas without such reefs. The results demonstrated that oyster breakwater reefs are particularly useful to reduce erosion at lower intertidal areas as the reefs successfully trapped sediments by dissipating waves. Oyster breakwater reefs modified the mudflat morphology up to 35 m distance at the lee side with accretion of 29 cm clayey sediments and erosion rate was two times lower during the monsoon period compared to control sites. By doing so, it enhanced the growth of new salt marsh vegetation and expanded their seaward edge effectively, thereby further stabilizing the unconsolidated sediments. Therefore, along the coast of Bangladesh, where oyster larval supply is abundant, the eco-engineered breakwater structures have the potential to contribute to a more sustainable shoreline protection against erosion.

    Chapter 6 aims to analyze the effects of these breakwater reefs on abundance and composition of macrobenthic soft-bottom assemblages together with transient and resident mobile fauna (fish, shrimp, crabs and other macro-invertebrates) in comparison with adjacent control sites without reefs. Seasonal influences were also considered to understand whether the effects of reefs depend on seasons. This study clearly indicates that oyster breakwater reefs had a positive effect on mudflat fauna communities. It shows higher abundances and biomass of fish and macroinvertebrates relative to the adjacent control sites. Seasonal variation was obvious, but didn’t overrule the reef impact. Multivariate analyses also demonstrated that the reef sites held distinct faunal communities, which differed from the control sites. Changes in macrobenthic community composition were associated with the variations in sediment load and characteristics, which were influenced by the breakwater reefs. Oyster breakwater reefs help to stabilize find sediments locally in lee side (landward) of the reefs, which is found as key reason to observe higher rates of macrobenthic colonization. Higher abundance of transient fish and mobile macro-invertebrates in reef sites indicated that breakwater oyster reefs attract mobile species as the reefs offer food and shelter. In fact, the study suggested that three-dimensional oyster breakwater reefs not only provide the shelter functions for mobile resident fauna, but also extend the ecosystem services related to nursing, breeding and foraging for numerous transient species by augmenting different prey resources for them. Though the ecological impact of oyster breakwater reefs was limited to a local area surrounding the reefs, this study provided hands-on evidence of ecological benefits using these reef configurations in estuarine and coastal habitats.

    This PhD study demonstrates that the use of the oyster breakwater reefs has multiple benefits. It can locally protect tidal flats against erosion and promote saltmarsh growth at the lee side of the reefs. These reefs act as breakwater and dissipate wave energy that accelerate the soft sediment deposition behind the structure and increase the bed level. This type of morphological changes may provide opportunities for mangrove planting. The study also showed that eco-engineered oyster reefs can support a high density of macro-benthos in reef areas, sessile macrofauna (oysters, barnacles, sea anemones etc.) on surface of reef substrates, large number of motile macro-invertebrates in reef system that attract transient nektons. The oyster breakwater reefs clearly has the potential to improve fishery production by providing high quality habitat and prey to a variety of commercially and ecologically important fishes, shrimps and crabs. Despite of having these benefits and opportunities, oyster breakwater reefs also have some limitations. Oysters need to settle, survive and grow at the designated place i.e. substrates in order to achieve long-term, persistent structures and self-sustainable reefs. This depends on the habitat characteristics of the site in the first place. Not all sites are equally suitable for oyster settlement survival and growth. Selection of the right site for creating oyster reefs is crucial. Therefore, we developed a HSI model that showed to be helpful in identifying potential sites (Chapter 2). The site can be further critically evaluated by a DEB model to understand seasonal dynamics in predicting oyster growth and reproduction (Chapter 4). Particularly, burial by sediment can cause significant loss of reef habitat. It can be avoided by increasing the heights of reef substrates based on the characteristics of the site. Additional constraints are the vulnerability of oysters for diseases and predation. Oyster drills (Urosalpinx spp.) and stone crabs (Myomenippe spp.) were found as meso-predators in the investigated sites, but their effects on oyster population need to be investigated.

    The intertidal rock oyster, S. cucullata can be ecologically engineered by providing hard substrates to settle on, that offers a kick-start for reef formation at places where they were lost or are desirable for coastal protection. Reef formation and development is however strongly dependent on the local environmental conditions governing oyster recruitment, survival and growth dynamics. These conditions can be highly dynamic, for example during the monsoon season. S. cucullata shows abilities to adapt to these conditions by regulating their physiological activities. The study shows that the S. cucullata populations are able to sustain in many estuarine areas along the southeast coast of Bangladesh as they can cope with the monsoonal climate. This makes them suitable for the role as eco-engineers for coastal protection. The study showed that artificial substrates can be used to develop self-sustaining oyster populations that contribute to coastal protection. Furthermore, oyster breakwater reefs dissipate the wave energy that reduces the hydrodynamic pressure on the foreshore of the primary dike and thus reduce the dike maintenance cost. Integration of oyster reefs with other ecosystems can add more benefits. Even it can enhance the possibility of doing oyster culture by enhancing larval supply in the area. Moreover, coexisting with other ecosystems viz., salt marsh and mangrove along with oyster breakwater reefs in the intertidal zone can act as bio-shield to prevent erosion and reduce the effect of cyclonic storm surges in the region. Therefore, oysters provide a great chance for Bangladesh to utilize them for the benefit of coastal people and environment.

    Oyster breakwater reefs promote adjacent mudflat stability and salt marsh growth in a monsoon dominated subtropical coast
    Chowdhury, Mohammed Shah Nawaz ; Walles, Brenda ; Sharifuzzaman, Sm ; Shahadat Hossain, M. ; Ysebaert, Tom ; Smaal, Aad C. - \ 2019
    Scientific Reports 9 (2019)1. - ISSN 2045-2322

    Oyster reefs have the potential as eco-engineers to improve coastal protection. A field experiment was undertaken to assess the benefit of oyster breakwater reefs to mitigate shoreline erosion in a monsoon-dominated subtropical system. Three breakwater reefs with recruited oysters were deployed on an eroding intertidal mudflat at Kutubdia Island, the southeast Bangladesh coast. Data were collected on wave dissipation by the reef structures, changes in shoreline profile, erosion-accretion patterns, and lateral saltmarsh movement and related growth. This was done over four seasons, including the rainy monsoon period. The observed wave heights in the study area ranged 0.1–0.5 m. The reefs were able to dissipate wave energy and act as breakwaters for tidal water levels between 0.5–1.0 m. Waves were totally blocked by the vertical relief of the reefs at water levels <0.5 m. On the lee side of the reefs, there was accretion of 29 cm clayey sediments with erosion reduction of 54% as compared to control sites. The changes caused by the deployed reefs also facilitated seaward expansion of the salt marsh. This study showed that breakwater oyster reefs can reduce erosion, trap suspended sediment, and support seaward saltmarsh expansion demonstrating the potential as a nature-based solution for protecting the subtropical coastlines.

    A verified habitat suitability model for the intertidal rock oyster, Saccostrea cucullata
    Chowdhury, Mohammed Shah Nawaz ; Wijsman, J.W.M. ; Hossain, M.S. ; Ysebaert, T. ; Smaal, A.C. - \ 2019
    PLoS ONE 14 (2019)6. - ISSN 1932-6203
    There is growing interest to restore oyster populations and develop oyster reefs for their role in ecosystem health and delivery of ecosystem services. Successful and sustainable oyster restoration efforts largely depend on the availability and selection of suitable sites that can support long-term growth and survival of oysters. Hence, in the present study a habitat suitability index (HSI) model was developed for the intertidal rock oyster (Saccostrea cucullata), with special attention: (1) to the role of the monsoon in the suitability of oyster habitats, and (2) to identify potential suitable sites along the south-eastern Bangladesh coast. Seven habitat factors were used as input variables for the HSI model: (1) water temperature; (2) salinity; (3) dissolved oxygen; (4) particulate inorganic matter (PIM); (5) pH; (6) Chlorophyll-a; and (7) water flow velocity. Seven field surveys were conducted at 80 locations to collect geospatial environmental data, which were then used to determine HSI scores using habitat suitability functions. The model results showed that the areas suitable (HSI >0.50) for oyster settlement and growth were characterized by relatively high salinities, Chlorophyll-a, dissolved oxygen and pH values. In contrast, freshwater dominated estuaries and nearby coastal areas with high suspended sediment were found less suitable (HSI <0.50) for oysters. HSI model results were validated with observed oyster distribution data. There was strong correlation between the HSI calculated by the model and observed oyster densities (r = 0.87; n = 53), shell height (r = 0.95; n = 53) and their condition index (r = 0.98; n = 53). The good correspondence with field data enhances the applicability of the HSI model as a quantitative tool for evaluating the quality of a site for oyster restoration and culture.
    Growth potential of rock oyster (Sacosstrea cucullata) exposed to dynamic environmental conditions simulated by a Dynamic Energy Budget model
    Chowdhury, Mohammed Shah Nawaz ; Wijsman, Johannes W.M. ; Shahadat Hossain, M. ; Ysebaert, Tom ; Smaal, Aad C. - \ 2019
    Journal of Sea Research 147 (2019). - ISSN 1385-1101 - p. 19 - 27.
    DEB model - Food - Monsoon - Saccostrea cucullata - Spatial and temporal variation
    A Dynamic Energy Budget (DEB) model for the intertidal rock oyster (Saccostrea cucullata) is presented and applied for three different sites (Sonadia, Kutubdia and Inani) located in the south-eastern coast of Bangladesh, covering a distinct environmental gradient. At the three sites, field observations of oyster growth, temperature, total particulate matter (TPM) and food availability (Chlorophyll-a and Particulate Organic Matter-POM) were carried out during a period from September 2014 to August 2017. DEB model simulations produced temporal, as well as spatial variation in oyster growth as a function of the prevailing environmental conditions. Growth rates of oysters were highest (shell increment: 3 cm yr) at Sonadia Island due to the high food concentrations. Growth rates were relatively low (shell increment: 1.94 cm yr−1) at Kutubdia and none of oysters survived in Inani during the monsoon period. At this site TPM concentrations were quite high (889 ± 101 mg l−1), but Chlorophyll-a was quite low (1.86 ± 0.16 μg l −1) during monsoon period. Temporal variation is largely monsoon driven. The period between November to May was the main growing season for oysters along the Bangladesh coast. In contrast, growth slowed down significantly during the monsoon months (June–September). DEB model simulations for S. cucullata showed good fit (Goodness of fit score > 8.54 out of 10 and low mean relative error, MRE <0.18) with observed growth data for all three locations throughout the seasons. Therefore, the model can be used to evaluate potential sites for oyster development either for aquaculture, restoration or coastal protection to enhance coastal resilience.
    Extension Agents’ Use and Acceptance of Social Media: The Case of the Department of Agricultural Extension in Bangladesh
    Kamruzzaman, Md. ; Chowdhury, Ataharul ; Paassen, Annemarie Van; Ganpat, Wayne - \ 2018
    Journal of International Agricultural and Extension Education 25 (2018)2. - ISSN 1077-0755 - p. 132 - 149.
    Information and Communication Technologies (ICTs) have been considered as key driving forces for enabling agricultural development ‒ the sector which provides livelihoods for majority ofthepopulation in Bangladesh. The Department of Agricultural Extension (DAE), the largest public sector agricultural extension service provider in Bangladesh, hasrecently enactedanew organizational policy for its staffs to use ICTs such as social media to provide better services. However, there is little or merely anecdotal evidence about how extension agents of DAE have been accepting and using social media for their professional work. Drawing onthetheoretical underpinnings of the Technology Acceptance Model (TAM),thisstudy is a first attempt to investigate social media use and acceptance amongextension agents in Bangladesh. Data wascollected using semi-structuredquestionnairesfrom 140 extension agents of DAE who work in the eastern region of Bangladesh. Both descriptive and inferential statistics were used to analyze the data. The findings indicate that most extension agents (51.4%) used social media forhalf an hour to one hour every day. Perceived ease of use (PEoU)andPerceived usefulness (PU) are the most influential elements that determine DAE staff acceptance ofsocial media for performing professional functions. Social media was perceived by extension agents as a means for improving professional performance, such asdisseminating agricultural information;garnering support fornew agricultural policy;networking with clients and colleagues and enabling coordinationof services provided by colleagues. Overall, the findings indicate potential usesof social media in an ICT-based agricultural development strategy in Bangladesh.
    DEB parameter estimation for Saccostrea cucullata (Born), an intertidal rock oyster in the Northern Bay of Bengal
    Chowdhury, Shah ; Wijsman, J.W.M. ; Hossain, M.S. ; Ysebaert, T. ; Smaal, A.C. - \ 2018
    Journal of Sea Research 142 (2018). - ISSN 1385-1101 - p. 180 - 190.
    DEB model - saccostrea-cuccullata - Parameter estimation - monsoon
    Dynamic Energy Budget (DEB) models describe the energy flow in organisms focusing on food assimilation and utilization for maintenance, growth and reproduction. In this paper, specific DEB parameters were obtained for
    the intertidal rock oyster Saccostrea cucullata, which has culture potential and important ecological functions in estuarine and coastal ecosystems along the Bay of Bengal, Bangladesh. Oyster samples were collected from natural oyster beds and used in a starvation experiment for 20 weeks in the laboratory. A sub-sample of starved oyster was used to record respiration rates and depletion of reserves was recorded by fortnightly measurements of flesh weight. Simultaneously, a group of oysters was used for physiological experiments and growth measurements, required for DEB parameter estimation. Consequently, Arrhenius temperature related parameters (i.e. TA, TL, TH, TAL, and TAH), shape coefficient (δM), volume specific maintenance rate ([PM]) and volume specific cost for structure ([EG]) were estimated using data from the respiration and starvation experiments. An iterative co-variation method was used to estimate the specific DEB parameters using the results of the physiological experiments, field observations and additional literature information. Estimated Arrhenius temperature was 5640 K, which applies between 297 and 305 K. Shape coefficient (δM=0.159) was low, compared to other oyster species that characterized the morphology of the oyster. Volume specific maintenance rate ([PM]) was equivalent to 17.99 J cm−3 day−1, while 2377 J cm−3 was estimated as the volume specific cost for structure ([EG]). These efforts provide opportunities to apply the DEB model for better understanding the energetics
    of bivalves under sub-tropical conditions. It is concluded that the hydrometeorological aspects, i.e. a monsoon regime and high turbidity levels, are quite different from temperate regions and drives the physiological traits of shellfish organisms.
    Elements of fishing community resilience to climate change in the coastal zone of Bangladesh
    Sharifuzzaman, S.M. ; Hossain, M.S. ; Chowdhury, Sayedur Rahman ; Sarker, Subrata ; Chowdhury, M.S.N. ; Chowdhury, M.Z.R. - \ 2018
    Journal of Coastal Conservation 22 (2018)6. - ISSN 1400-0350 - p. 1167 - 1176.
    Analytic hierarchy process (AHP) - Fishing community - Hatiya Island - Livelihood assets - Resilience

    Resilience has been conceptualized in various ways by anthropologists, ecologists, systems scientists and engineers; the boundaries of resilience are subjective and context dependent. Consequently, choosing the standards and metrics for assessing resilience remains key challenges for policy makers. In this study, using multicriteria evaluation of 40 basic criteria of human, physical, financial, natural and social assets, we have identified several elements, such as experienced fishermen, natural abundance of hilsa (Tenualosa ilisha), ability to assert decision on fish selling, nets and boats ownership, social harmony and capacity of buying food as essential livelihood assets for the fishermen at Hatiya Island, Bangladesh. These assets may enhance the relative resilience of the fishing community of the island to climate change by as much as 20–40%. The results of this study will improve our understanding of the elements that lead to resilience at the community level.

    Global, regional, and national burden of neurological disorders during 1990–2015: a systematic analysis for the Global Burden of Disease Study 2015
    Feigin, V.L. ; Krishnamurthi, R.V. ; Theadom, A.M. ; Abajobir, A.A. ; Mishra, S.R. ; Ahmed, M.B. ; Abate, K.H. ; Mengistie, M.A. ; Wakayo, T. ; Abd-Allah, F. ; Abdulle, A.M. ; Abera, S.F. ; Mohammed, K.E. ; Abyu, G.Y. ; Asgedom, S.W. ; Atey, T.M. ; Betsu, B.D. ; Mezgebe, H.B. ; Tuem, K.B. ; Woldu, M.A. ; Aichour, A.N. ; Aichour, I. ; Aichour, M.T. ; Akinyemi, R.O. ; Alabed, S. ; Al-Raddadi, R. ; Alvis-Guzman, N. ; Amare, A.T. ; Ansari, H. ; Anwari, P. ; Ärnlöv, J. ; Fereshtehnejad, S. ; Weiderpass, E. ; Havmoeller, R. ; Asayesh, H. ; Avila-Burgos, L. ; Avokpaho, E.F.G.A. ; Afrique, L.E.R.A.S. ; Azarpazhooh, M.R. ; Barac, A. ; Barboza, M. ; Barker-Collo, S.L. ; Bärnighausen, T. ; Farvid, M.S. ; Mohammed, S. ; Bedi, N. ; Beghi, E. ; Giussani, G. ; Bennett, D.A. ; Hay, S.I. ; Goulart, A.C. ; Santos, I.S. ; Bensenor, I.M. ; Lotufo, P.A. ; Berhane, A. ; Jeemon, P. ; Bhaumik, S. ; Dandona, L. ; Dandona, R. ; Kumar, G.A. ; Birlik, S.M. ; Biryukov, S. ; Casey, D. ; Foreman, K.J. ; Goldberg, E.M. ; Khalil, I.A. ; Kyu, H.H. ; Manhertz, T. ; Mokdad, A.H. ; Naghavi, M. ; Nguyen, G. ; Nichols, E. ; Smith, M. ; Carabin, H. ; Roth, G.A. ; Stanaway, J.D. ; Vos, T. ; Ellenbogen, R.G. ; Jakovljevic, M.B. ; Tirschwell, D.L. ; Zunt, J.R. ; Boneya, D.J. ; Hambisa, M. ; Bulto, L.N.B. ; Carabin, H. ; Castañeda-Orjuela, C.A. ; Catalá-López, F. ; Tabarés-Seisdedos, R. ; Chen, H. ; Chitheer, A.A. ; Chowdhury, R. ; Christensen, H. ; Deveber, G.A. ; Dharmaratne, S.D. ; Do, H.P. ; Nguyen, C.T. ; Nguyen, Q.L. ; Nguyen, T.H. ; Nong, V.M. ; Sheth, K.N. ; Dorsey, E.R. ; Eskandarieh, S. ; Fischer, F. ; Majeed, A. ; Steiner, T.J. ; Rawaf, S. ; Shakir, R. ; Shoman, H. ; Geleijnse, J.M. ; Gillum, R.F. ; Gona, P.N. ; Gugnani, H.C. ; Gupta, R. ; Hachinski, V. ; Hamadeh, R.R. ; Hankey, G.J. ; Hareri, H.A. ; Heydarpour, P. ; Sahraian, M.A. ; Kasaeian, A. ; Malekzadeh, R. ; Roshandel, G. ; Sepanlou, S.G. ; Hotez, P.J. ; Javanbakht, M. ; Jonas, J.B. ; Kalkonde, Y. ; Kandel, A. ; Karch, A. ; Kastor, A. ; Rahman, M.H.U. ; Keiyoro, P.N. ; Khader, Y.S. ; Khan, E.A. ; Khang, Y. ; Khoja, A.T.A. ; Tran, B.X. ; Khubchandani, J. ; Kim, D. ; Kim, Y.J. ; Kivimaki, M. ; Kokubo, Y. ; Kosen, S. ; Kravchenko, M. ; Piradov, M.A. ; Varakin, Y.Y. ; Defo, B.K. ; Kulkarni, C. ; Kumar, R. ; Larsson, A. ; Lavados, P.M. ; Li, Y. ; Liang, X. ; Liben, M.L. ; Lo, W.D. ; Logroscino, G. ; Loy, C.T. ; Mackay, M.T. ; Meretoja, A. ; Szoeke, C.E.I. ; Abd El Razek, H.M. ; Mantovani, L.G. ; Massano, J. ; Mazidi, M. ; McAlinden, C. ; Mehata, S. ; Mehndiratta, M.M. ; Memish, Z.A. ; Mendoza, W. ; Mensah, G.A. ; Wijeratne, T. ; Miller, T.R. ; Mohamed Ibrahim, N. ; Mohammadi, A. ; Moradi-Lakeh, M. ; Velasquez, I.M. ; Musa, K.I. ; Ngunjiri, J.W. ; Ningrum, D.N.A. ; Norrving, B. ; Stein, D.J. ; Noubiap, J.J.N. ; Ogbo, F.A. ; Renzaho, A.M.N. ; Owolabi, M.O. ; Pandian, J.D. ; Parmar, P.G. ; Pereira, D.M. ; Petzold, M. ; Phillips, M.R. ; Poulton, R.G. ; Pourmalek, F. ; Qorbani, M. ; Rafay, A. ; Rai, R.K. ; Rajsic, S. ; Ranta, A. ; Rezai, M.S. ; Rubagotti, E. ; Sachdev, P. ; Safiri, S. ; Sahathevan, R. ; Samy, A.M. ; Santalucia, P. ; Sartorius, B. ; Satpathy, M. ; Sawhney, M. ; Saylan, M.I. ; Shaikh, M.A. ; Shamsizadeh, M. ; Sheth, K.N. ; Shigematsu, M. ; Silva, D.A.S. ; Sobngwi, E. ; Sposato, L.A. ; Stovner, L.J. ; Suliankatchi Abdulkader, R. ; Tanne, D. ; Thrift, A.G. ; Topor-Madry, R. ; Truelsen, T. ; Ukwaja, K.N. ; Uthman, O.A. ; Yonemoto, N. ; Venketasubramanian, N. ; Vlassov, V.V. ; Wadilo, F. ; Wallin, M.T. ; Westerman, R. ; Wiysonge, C.S. ; Wolfe, C.D. ; Xavier, D. ; Xu, G. ; Yano, Y. ; Yimam, H.H. ; Yonemoto, N. ; Yu, C. ; Zaidi, Z. ; Zaki, M.E. - \ 2017
    The Lancet Neurology 16 (2017)11. - ISSN 1474-4422 - p. 877 - 897.

    Background Comparable data on the global and country-specific burden of neurological disorders and their trends are crucial for health-care planning and resource allocation. The Global Burden of Diseases, Injuries, and Risk Factors (GBD) Study provides such information but does not routinely aggregate results that are of interest to clinicians specialising in neurological conditions. In this systematic analysis, we quantified the global disease burden due to neurological disorders in 2015 and its relationship with country development level. Methods We estimated global and country-specific prevalence, mortality, disability-adjusted life-years (DALYs), years of life lost (YLLs), and years lived with disability (YLDs) for various neurological disorders that in the GBD classification have been previously spread across multiple disease groupings. The more inclusive grouping of neurological disorders included stroke, meningitis, encephalitis, tetanus, Alzheimer's disease and other dementias, Parkinson's disease, epilepsy, multiple sclerosis, motor neuron disease, migraine, tension-type headache, medication overuse headache, brain and nervous system cancers, and a residual category of other neurological disorders. We also analysed results based on the Socio-demographic Index (SDI), a compound measure of income per capita, education, and fertility, to identify patterns associated with development and how countries fare against expected outcomes relative to their level of development. Findings Neurological disorders ranked as the leading cause group of DALYs in 2015 (250·7 [95% uncertainty interval (UI) 229·1 to 274·7] million, comprising 10·2% of global DALYs) and the second-leading cause group of deaths (9·4 [9·1 to 9·7] million], comprising 16·8% of global deaths). The most prevalent neurological disorders were tension-type headache (1505·9 [UI 1337·3 to 1681·6 million cases]), migraine (958·8 [872·1 to 1055·6] million), medication overuse headache (58·5 [50·8 to 67·4 million]), and Alzheimer's disease and other dementias (46·0 [40·2 to 52·7 million]). Between 1990 and 2015, the number of deaths from neurological disorders increased by 36·7%, and the number of DALYs by 7·4%. These increases occurred despite decreases in age-standardised rates of death and DALYs of 26·1% and 29·7%, respectively; stroke and communicable neurological disorders were responsible for most of these decreases. Communicable neurological disorders were the largest cause of DALYs in countries with low SDI. Stroke rates were highest at middle levels of SDI and lowest at the highest SDI. Most of the changes in DALY rates of neurological disorders with development were driven by changes in YLLs. Interpretation Neurological disorders are an important cause of disability and death worldwide. Globally, the burden of neurological disorders has increased substantially over the past 25 years because of expanding population numbers and ageing, despite substantial decreases in mortality rates from stroke and communicable neurological disorders. The number of patients who will need care by clinicians with expertise in neurological conditions will continue to grow in coming decades. Policy makers and health-care providers should be aware of these trends to provide adequate services. Funding Bill & Melinda Gates Foundation.

    The barley (Hordeum vulgare) cellulose synthase-like D2 gene (HvCslD2) mediates penetration resistance to host-adapted and nonhost isolates of the powdery mildew fungus
    Douchkov, Dimitar ; Lueck, Stefanie ; Hensel, Goetz ; Kumlehn, Jochen ; Rajaraman, Jeyaraman ; Johrde, Annika ; Doblin, Monika S. ; Beahan, Cherie T. ; Kopischke, Michaela ; Fuchs, René ; Lipka, Volker ; Niks, Rients E. ; Bulone, Vincent ; Chowdhury, Jamil ; Little, Alan ; Burton, Rachel A. ; Bacic, Antony ; Fincher, Geoffrey B. ; Schweizer, Patrick - \ 2016
    New Phytologist 212 (2016)2. - ISSN 0028-646X - p. 421 - 433.
    Blumeria graminis - cell wall - cellulose synthase-like - CSL - RNAi - transgenic barley plants

    Cell walls and cellular turgor pressure shape and suspend the bodies of all vascular plants. In response to attack by fungal and oomycete pathogens, which usually breach their host's cell walls by mechanical force or by secreting lytic enzymes, plants often form local cell wall appositions (papillae) as an important first line of defence. The involvement of cell wall biosynthetic enzymes in the formation of these papillae is still poorly understood, especially in cereal crops. To investigate the role in plant defence of a candidate gene from barley (Hordeum vulgare) encoding cellulose synthase-like D2 (HvCslD2), we generated transgenic barley plants in which HvCslD2 was silenced through RNA interference (RNAi). The transgenic plants showed no growth defects but their papillae were more successfully penetrated by host-adapted, virulent as well as avirulent nonhost isolates of the powdery mildew fungus Blumeria graminis. Papilla penetration was associated with lower contents of cellulose in epidermal cell walls and increased digestion by fungal cell wall degrading enzymes. The results suggest that HvCslD2-mediated cell wall changes in the epidermal layer represent an important defence reaction both for nonhost and for quantitative host resistance against nonadapted wheat and host-adapted barley powdery mildew pathogens, respectively.

    First Record of Porpita porpita (Cnidaria: Hydrozoa) from the coral reef ecosystem, Bangladesh
    Shah Nawaz Chowdhury, M. ; Sharifuzzaman, S.M. ; Chowdhury, Sayedur Rahman ; Rashed-Un-Nabi, Md ; Hossain, M.S. - \ 2016
    Ocean Science Journal 51 (2016)2. - ISSN 1738-5261 - p. 293 - 297.
    Bangladesh - Bay of Bengal - Hydrozoa - Porpita - Saint Martin’s Island

    The occurrence of Porpita porpita is reported, for the first time, in the coral island of St. Martin’s located in the southeastern coastal region of Bangladesh. P. porpita was found to occur in the lower littoral zone and beach rock pools, together with molluscan species, and collected during the pre-monsoon season when both water temperature (> 30°C) and salinity (> 30‰) tend to reach a maximum. This study recounts some details on the discovery and description of the species, and thus extends the global distribution and range limits of the genus Porpita.

    Supplementary data: Combined biotic and abiotic stress resistance in tomato
    Kissoudis, C. ; Chowdhury, Rawnaq ; Heusden, A.W. van; Wiel, C.C.M. van de; Finkers, H.J. ; Visser, R.G.F. ; Bai, Y. ; Linden, C.G. van der - \ 2016
    Wageningen UR
    solanum lycopersicum - tomatoes - disease resistance - stress tolerance - defence mechanisms - plant diseases - abiotic injuries - stress response - phenotypic variation - genetic analysisplant breeding - salt tolerance
    Abiotic and biotic stress factors are the major constrains for the realization of crop yield potential. As climate change progresses, the spread and intensity of abiotic as well as biotic stressors is expected to increase, with increased probability of crops being exposed to both types of stress. Shielding crops from combinatorial stress requires a better understanding of the plant’s response and its genetic architecture. In this study, we evaluated resistance to salt stress, powdery mildew and to both stresses combined in tomato, using the S. habrochaites LYC4 introgression line (IL) population. The IL population segregated for both salt stress tolerance and powdery mildew resistance. Using SNP array marker data, QTLs were identified for salt tolerance as well as Na+ and Cl- accumulation. Salt stress increased the susceptibility of the population to powdery mildew in an additive manner. Phenotypic variation for disease resistance was reduced under combined stress as indicated by the coefficient of variation (CV). No correlation was found between disease resistance and Na+ and Cl- accumulation under combined stress Most genetic loci were specific for either salt stress tolerance or powdery mildew resistance. These findings increase our understanding of the genetic regulation of responses to abiotic and biotic stress combinations and can provide leads to more efficiently breeding for tomatoes and other crops with a high level of disease resistance while maintaining their performance in combination with abiotic stress.
    Eco-engineered coastal defense integrated with sustainable aquatic food production in Bangladesh (ECOBAS)
    Tangelder, M. ; Ysebaert, T. ; Chowdhury, Shah ; Reinhard, A.J. ; Doorn, F. ; Hossain, M. ; Smaal, A.C. - \ 2015
    IMARES (Report / IMARES C048/15) - 39
    coastal areas - coastal management - food production - bangladesh - kustgebieden - kustbeheer - voedselproductie - bangladesh
    The objective of the ECOBAS project is to provide the coastal people of Bangladesh with an alternative approach for adaptation to coastal erosion and flooding. By using the concept of “eco-engineering” the natural resistance of shellfish reefs against hydrodynamic forces reduces human vulnerability to coastal erosion and flooding, and delivers a source of aquatic food. ECOBAS stands for ECO-engineered Coastal Defence Integrated with Sustainable Aquatic Food Production in BAngladeSh, and was executed by a multidisciplinary team of Dutch and Bangladesh research institutes. This report summarizes the outcomes of this study. It is not an in-depth report where scientific outcomes are discussed, but a summary for the funding agencies. The ECOBAS project was funded by Partners for Water. Also the Embassy of the Kingdom of the Netherlands financed extra monitoring activities in the second phase of the project which enabled generation of more data and a broader understanding of the research.
    Combined biotic and abiotic stress resistance in tomato
    Kissoudis, C. ; Chowdhury, R. ; Heusden, A.W. van; Wiel, C.C.M. van de; Finkers, H.J. ; Visser, R.G.F. ; Bai, Y. ; Linden, C.G. van der - \ 2015
    Euphytica 202 (2015)2. - ISSN 0014-2336 - p. 317 - 332.
    salt tolerance - oidium-neolycopersici - salinity tolerance - botrytis-cinerea - powdery mildew - abscisic-acid - plant-disease - phenotypic plasticity - solanum-lycopersicon - climate-change
    Abiotic and biotic stress factors are the major constrains for the realization of crop yield potential. As climate change progresses, the spread and intensity of abiotic as well as biotic stressors is expected to increase, with increased probability of crops being exposed to both types of stress. Shielding crops from combinatorial stress requires a better understanding of the plant’s response and its genetic architecture. In this study, we evaluated resistance to salt stress, powdery mildew and to both stresses combined in tomato, using the Solanum habrochaites LYC4 introgression line (IL) population. The IL population segregated for both salt stress tolerance and powdery mildew resistance. Using SNP array marker data, QTLs were identified for salt tolerance as well as Na+ and Cl- accumulation. Salt stress increased the susceptibility of the population to powdery mildew in an additive manner. Phenotypic variation for disease resistance was reduced under combined stress as indicated by the coefficient of variation. No correlation was found between disease resistance and Na+ and Cl- accumulation under combined stress Most genetic loci were specific for either salt stress tolerance or powdery mildew resistance. These findings increase our understanding of the genetic regulation of responses to abiotic and biotic stress combinations and can provide leads to more efficiently breeding tomatoes and other crops with a high level of disease resistance while maintaining their performance in combination with abiotic stress.
    Transforming the Roles of a Public Extension Agency to Strengthen Innovation: Lessons from the National Agricultural Extension Project in Bangladesh
    Chowdhury, A.H. ; Odame, H.H. ; Leeuwis, C. - \ 2014
    The Journal of Agricultural Education and Extension 20 (2014)1. - ISSN 1389-224X - p. 7 - 25.
    Purpose: The rapidly evolving nature of agricultural innovation processes in low-income countries requires agricultural extension agencies to transform the classical roles that previously supported linear information dissemination and adoption of innovation. In Bangladesh, strengthening agricultural innovation calls for facilitation of interactive communication and a wide range of mediation tasks within (and between) stakeholders operating in different social spheres. This paper examines how a public-sector agricultural extension agency has attempted to change its roles in implementing a major agricultural extension project in order to strengthen agricultural innovation. This role adjustment is a key outcome of an effectively functioning innovation system because it enables collective actions and enhances performance that meets the needs of clients. Methodology: The study uses a case study design that includes mixed methods data collection and analysis. Using interviews, group discussions, observations, and a semi-structured survey, data were collected from stakeholders of a major regional agricultural extension project in Bangladesh. Findings: The findings suggest that the agricultural extension agency missed the opportunity to deliver the agricultural extension project in such a way that it strengthens collective actions and functions that would respond to the needs of all clients within the system. This is due to institutions that create obstacles within the agricultural innovation system. These obstacles relate to the tendency to remain in a linear paradigm of technology transfer and dependency on public service, the under-estimation and depreciation of intermediary roles of extension personnel (e.g. brokering, negotiating, convening), and finally, an inability to foresee extension methods (e.g. training, demonstration) as the facilitation of interactive learning and knowledge embedding processes. Originality/ Practical Implications: This is the first case study from Bangladesh that provides insights into extant initiatives taken by a public-sector agricultural extension agency to put innovation system thinking into use. The paper discusses a number of lessons, which will be useful for evolving new forms of extension work and applying agricultural innovation systems thinking in low-income countries.
    Oyster reefs: opportunities for coastal protection and aquatic food production
    Chowdhury, M.S.N. ; Hossain, M.S. ; Ysebaert, T. ; Smaal, A.C. - \ 2014
    Preparations for the Bangladesh Delta Plan
    Choudhury, G.A. ; Terwisscha Van Scheltinga, C.T.H.M. ; Bergh, L.M.J. van den; Chowdhury, F. ; Heer, J. de; Hossain, M. - \ 2012
    Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2300)
    ruimtelijke ordening - regionale planning - waterbeheer - klimaatverandering - delta - bangladesh - physical planning - regional planning - water management - climatic change - deltas - bangladesh
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