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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    Bringing in the floods : a comparative study on controlled flooding in the Dutch, Bangladesh and Vietnamese deltas
    Staveren, Martijn F. van - \ 2017
    Wageningen University. Promotor(en): J.P.M. Tatenhove, co-promotor(en): J.F. Warner; P. Wester. - Wageningen : Wageningen University - ISBN 9789463437035 - 174
    water management - flooding - deltas - hydraulic engineering - rivers - environmental management - environmental policy - environmental control - netherlands - vietnam - bangladesh - waterbeheer - inundatie - delta's - waterbouwkunde - rivieren - milieubeheer - milieubeleid - milieubeheersing - nederland - vietnam - bangladesh

    This thesis investigates contested initiatives to restore controlled flooding in the deltas of the Dutch, Bangladesh and Vietnamese (Mekong) deltas. Restoring controlled flooding is a seemingly contradictory measure in densely populated delta areas, where approaches based on full flood prevention has been typically dominant for decades. This has instigated the question how the emergence of restored controlled flooding initiatives can be explained. Related, this study reflects on how controlled flooding could contribute to long-term flood risk management and sustainable development in deltas, which are simultaneously attractive and vulnerable places for humans to live in. In order to answer this question, a case study approach has been used to investigate social, environmental and technological factors that have shaped controlled flooding initiatives. Cases have been identified that materialized under different conditions: from very dynamic delta environments to relatively stable ones, and from interventions driven by “top-down” policies to “bottom-up” action to modify or remove embankments. This thesis has an article-based structure, which means that individual chapters (2-5) have been designed for publication with peer reviewed academic journals. Chapter 1 provides the general background information, problem definition, and objectives. Chapter 6 ties together the findings of the individual case study chapters and presents the conclusions.

    Chapter 2 conceptualizes deltas as interacting social-ecological-technological systems. It argues that a better understanding of how hydraulic infrastructure influences social processes and environmental dynamics in deltas is critical to understand how deltas evolve over time. By means of the delta trajectories concept, the chapter presents a way to understand this interaction. It also presents a way to understand the sustainability of a delta trajectory, and discusses how new flood management concepts might contribute to “realigning” the development trajectory towards more sustainable system states.

    In Chapter 3, the first controlled flooding case is investigated. The Noordwaard is an agricultural polder, located at the junction of tides and riverine discharge in the Netherlands. As part of the Room for the River programme, the northern embankments were lowered which enables the inflow of water during high water levels in the river Merwede. This reduces peak water levels in the river, supports the adjacent freshwater Biesbosch wetland by means of restored water dynamics, but also affects the possibilities for agricultural production. The chapter highlights that a strong coupling can be observed between the domains of water safety and nature development objectives, and that a top-down decision concluded a long stakeholder negotiation processes. From the perspective of “subsiding polder lands,” controlled flooding is not regarded for its strategic importance, as excessive sedimentation would hamper the intended design discharge of the area.

    Chapter 4 explores the Tidal River Management concept. In the coastal zone of Bangladesh, community-enforced embankment breaches have opened up some of the polders or low-lying areas called “beels,” and exposed them to tidal influence again. Besides stimulating agricultural production and providing safer places to live in, the extensive network of polder embankments also caused increased sedimentation in the region’s rivers, and water logging in enclosed areas due to insufficient drainage possibilities. The chapter highlights that policy debates in Bangladesh have revolved around adopting “open” or “closed” approaches, where TRM represents a hybrid form. The case showed that TRM involves water management and sediment management, and that it represented a “social opening up” for local communities and NGOs to get involved with water projects and embankment removal.

    Plans to restore seasonal flooding in the Mekong delta are center stage in Chapter 5. The Mekong delta system is very dynamic and dealing with the delta’s water resources, in connection with intensive rice production, have been heavily debated by Vietnamese and international policy makers. This chapter investigates a number of older and more recent long-term development plans for the Mekong delta. This analysis highlights how ideas about controlled flooding and flood control have gradually evolved over time. The most recent delta management plan suggests to restore seasonal flooding in some parts of the delta, as a way to safeguard downstream urban areas from peak flows, and as a way to improve the conditions for agricultural production.

    Chapter 6 summarizes the findings of the case study chapters one by one, and concisely answers the research questions. It highlights key similarities and differences when it comes to social, environmental and technological dimensions, and discusses these findings with the literature on flood risk management policy, complex adaptive systems research, and delta studies. The findings demonstrate that environmental dynamics have been critical to emphasize the potential of restoring controlled flooding, but that social and technological factors have been important enablers or constrainers for controlled flooding initiatives to take shape. In itself, controlled flooding reconciles ecosystem-based ideas about flood management with more mainstream policies based on flood control. For this reason controlled flooding can be seen as a “niche-development” with limited influence on how flood management policies, and environmental delta systems, evolve. At the same time, controlled flooding has been acknowledged for its strategic opportunities, for example when it comes to diverting peak water discharges, land heightening by means of capturing suspended sediment, and by providing nutrient for agricultural. This offers opportunities for further thinking about and conceptual development of controlled flooding.

    Administrative co-management in special use forests of Vietnam
    Dung, Nguyen Kim - \ 2017
    Wageningen University. Promotor(en): Arthur Mol, co-promotor(en): Simon Bush. - Wageningen : Wageningen University - ISBN 9789462579866 - 183
    forests - forest administration - forest management - nature conservation - environmental protection - vietnam - bossen - bosbeheer - bosbedrijfsvoering - natuurbescherming - milieubescherming - vietnam

    To protect its natural heritage and biodiversity, Vietnam has established a system of ‘special use forest’ (SUFs) which is “the backbone of the national protected areas”. The ineffective management of SUFs based solely on the state leads to a decline in biodiversity and density of the forests. Recognizing this, collaborative or ‘co’-management for SUFs is advocated to get more participation and shared responsibilities and rights between government and non-state actors. However, it is widely noted that co-management is a particularly great challenge in Vietnam because of the nature of strong state control, decades of SUF conflicts, and the lack of capacity and initiatives of communities to negotiate with the government in co-management arrangements. This PhD thesis questions the degree to which co-management can be put in Vietnamese SUFs and the degree of ‘adaptiveness’ it can engender. Conditions of the economic, political and social context surrounding SUFs becomes key to any understanding of how co-management can be implemented, including insights into how co-management may need to be amended to adjust to ‘fit’ the context of mono-organisational states.

    Aquaculture Innovation in Vietnam
    Rurangwa, E. ; Baumgartner, U. ; Nguyen, H.M. ; Vis, J.W. van de - \ 2016
    Yerseke : Wageningen Marine Research (Wageningen Marine Research report C097/16) - 28
    aquaculture - innovations - tilapia - fishes - shrimps - crabs - vietnam - aquacultuur - innovaties - tilapia - vissen - garnalen - krabben (schaaldieren) - vietnam
    Improving sustainability of striped catfish (Pangasianodon hypophthalmus) farming in the Mekong Delta, Vietnam through recirculation technology
    Nguyen, Nhut - \ 2016
    Wageningen University. Promotor(en): Johan Verreth, co-promotor(en): Marc Verdegem. - Wageningen : Wageningen University - ISBN 9789462579194 - 180
    fish culture - recirculating aquaculture systems - aquaculture - fishes - nutrients - vietnam - visteelt - recirculatie aquacultuur systemen - aquacultuur - vissen - voedingsstoffen - vietnam

    The aim of this thesis was to document improvements in sustainability indicators of striped catfish (Pangasianodon hypophthalmus, Sauvage, 1878) production through the application of recirculation and waste treatment techniques. To be able to document improvements in sustainability, in each system studied the same set of twenty sustainability indicators were measured. Indicators related to the use of fingerlings, water, diesel oil, electricity, labor, chemicals and antibiotics.

    Also, indicators related to nutrient utilization efficiencies and waste discharge were monitored. In addition, a sampling scheme, allowing to calculate organic matter, nitrogen, phosphorous and chemical oxygen demand mass balances covering a full production cycle and applicable in different production systems, was developed. Overall, from a sustainability point of view, striped catfish culture in ponds compared well to other important aquaculture species.

    Although favorable, it was concluded that water, chemicals and antibiotics use, survival, and the amounts of waste discharged could be further reduced through recirculation and treatment of solid wastes. The realized improvements through RAS technology and waste treatment technology were quantified in lab or pilot scale experiments. Large improvements were realized for water, antibiotic and chemical use, survival, waste discharge and color grade of striped catfish fillets at harvest. In addition, in RAS, utilization efficiencies of nutrients supplied through feeding were improved.

    Solid wastes removed from ponds or RAS could be partially re-used by making compost or producing methane for generating electricity. Another approach tested was the integration of a denitrification reactor in the recirculation system, which allowed to decompose solid waste and reduce nitrogen discharge. Denitrification in RAS did not affect fish growth, nutrient retention efficiencies and the quality of the fish fillets produced, and thus also improved sustainability of striped catfish farming.

    In conclusion, application of recirculation and waste treatment techniques tested in this thesis improved the sustainability for striped catfish culture. The challenge remains to scale up RAS and waste treatment technology for striped catfish to the production volumes handled in outdoor ponds without raising production costs.

    Economic analysis of technological innovations to improve sustainability of pangasius production in Vietnam
    Ngoc, Pham Thi Anh - \ 2016
    Wageningen University. Promotor(en): Alfons Oude Lansink; Johan Verreth, co-promotor(en): Miranda Meuwissen. - Wageningen : Wageningen University - ISBN 9789462579880 - 141
    fish production - fishes - innovations - economic analysis - sustainability - fish culture - vietnam - visproductie - vissen - innovaties - economische analyse - duurzaamheid (sustainability) - visteelt - vietnam

    In response to increasing concerns about sustainable production, a growing number of European customers expect seafood products to be certified, for example by the Aquaculture Stewardship Council (ASC) certification. Water purification technologies such as Recirculating Aquaculture Systems (RAS) could be a potential solution to reduce waste discharge and to improve water quality in fish ponds as a response to environmental regulations. In order to provide useful insights to consider investments in RAS, the overall objective of this thesis was to perform an economic analysis of technological innovations such as RAS to improve the sustainability of pangasius production in Vietnam.

    This thesis first uses Data Envelopment Analysis to measure input- and output-specific technical and scale inefficiency of pangasius farmers in the traditional system and uses a bootstrap truncated regression to assess the impact of farmers’ demographics and farm characteristics on these technical inefficiencies. Second, the economic feasibility of RAS in pangasius farming is analysed using a capital budgeting approach and stochastic simulation accounting for uncertainty in key parameters. Next, key determinants influencing the adoption of RAS by pangasius farmers are investigated using a choice experiment. Finally, price transmission along the international supply chain of pangasius, from the Vietnamese farm to the Polish retail stage is analysed using a vector autoregressive error correction model framework.

    The results show that inadequate management skills in using capital assets and improper methods for producing fish are the main challenges for enhancing the performance of Vietnamese pangasius production. Location of the farm in a saltwater intrusion area is positively associated with inefficiency of producing fish. The results suggest further that when shifting from the traditional system to RAS, the Net Present Value (NPV) of the investment in RAS is expected to substantially increase, for both medium (1-3 ha) and large (equal or greater than 3 ha) farms. Lack of trust in receiving a price premium, inadequate access to finance and uncertainty about the actual performance of RAS systems are constraints for the adoption of RAS. Finally, our study provides evidence that price signals at the Polish-Vietnamese retail stage were transmitted back to wholesale, export and Vietnamese pangasius farms stages.

    Sustainability metrics for agri-food supply chains
    Gaitán Cremaschi, D. - \ 2016
    Wageningen University. Promotor(en): Alfons Oude Lansink, co-promotor(en): Frits van Evert; Miranda Meuwissen. - Wageningen University - ISBN 9789462578012 - 244
    food supply - food chains - agro-industrial chains - sustainability - western europe - vietnam - voedselvoorziening - voedselketens - agro-industriële ketens - duurzaamheid (sustainability) - west-europa - vietnam

    Enhancing sustainability in food production requires knowledge about the economic, environmental and social performance of the various stages of agri-food supply chains. An integrated indicator can provide synthetized information about the extent to which food products are sustainably produced and can guide sustainability improvements. The overall objective of this thesis was to perform integrated assessments of relative sustainability performance of (stages of) agri-food supply chains using integrated indicators. To achieve the overall objective this thesis first developed a theoretical framework for benchmarking agri-food supply chains in terms of their relative sustainability performance. Two integrated indicators were proposed, i.e. the Social Profit indicator that integrates sustainability performance indicators using prices and the Technical Inefficiency indicator that uses distance functions. Next, the Social Profit indicator was illustrated for Brazilian soybean meal chains: non-genetically modified (non-GM) and genetically modified (GM) chains. Further, relative sustainability performance (economic and environmental) of specialized potato farms in Germany and the Netherlands was assessed using both the Social Profit indicator and the Technical Inefficiency indicator. Finally, an alternative approach, the Nerlovian Social Profit Inefficiency indicator, was used for the assessment of relative sustainability performance of coffee farms in Vietnam. The results of this thesis suggests that the three proposed integrated indicators can be used in different socio-economic and environmental contexts to capture the multidimensional nature of relative agri-food supply chain sustainability. Their implementation helps to overcome some of the limitations of the single-issue and composite indicators that are commonly used in sustainability assessments such as incommensurability, subjectivity and comparability. The indicators provide information that can be used by businesses, stakeholders and policy makers to identify opportunities for relative sustainability performance improvements of agri-food supply chains.

    Keywords: Total Factor Productivity, Total Price Recovery, technical inefficiency, agri-food supply chain, externality, social profit.

    Biofuel production in Vietnam : Greenhouse gas emissions and socioeconomic impacts
    Thanh, L. le - \ 2016
    Wageningen University. Promotor(en): Ekko van Ierland; Xueqin Zhu. - Wageningen : Wageningen University - ISBN 9789462576186 - 197
    biofuels - greenhouse gases - environmental economics - emission - socioeconomics - fuels - natural resources - vietnam - biobrandstoffen - broeikasgassen - milieueconomie - emissie - sociale economie - brandstoffen - natuurlijke hulpbronnen - vietnam
    The overall objective of this thesis is to study the energy efficiency, GHG emission savings, and the economic viability of biofuels as energy for transportation and to examine the impacts of biofuel policies on food production, welfare, and emission in Vietnam.
    Meer doen met mest
    Didde, R. ; Vellinga, Th.V. ; Andeweg, K. ; Teenstra, E.D. - \ 2015
    WageningenWorld (2015)4. - ISSN 2210-7908 - p. 34 - 39.
    mestverwerking - ontwikkelingslanden - mestvergisting - biogas - bemesting - kringlopen - vietnam - landbouwontwikkeling - manure treatment - developing countries - manure fermentation - biogas - fertilizer application - cycling - vietnam - agricultural development
    Wageningen UR probeert boeren in ontwikkelingslanden ervan te overtuigen meer te doen met de mest van hun vee. Dat kan bijdragen aan de energievoorziening, de conditie van de bodem en vermindering van de uitstoot van broeikasgassen. In Vietnam worden de eerste resultaten geboekt.
    We have to eat, right? : food safety concerns and shopping for daily vegetables in modernizing Vietnam
    Wertheim-Heck, S.C.O. - \ 2015
    Wageningen University. Promotor(en): Gert Spaargaren. - Wageningen : Wageningen University - ISBN 9789462575745 - 241
    voedselveiligheid - voedselkwaliteit - groenten - consumenten - consumptiepatronen - consumptie - milieubeleid - vietnam - zuidoost-azië - food safety - food quality - vegetables - consumers - consumption patterns - consumption - environmental policy - vietnam - south east asia

    This thesis analyses how people during everyday life confront real food safety risks that are difficult to influence and come to grips with and focuses on food safety risks in modernizing Vietnam.

    Over the past 40 years Vietnam has developed from war torn country with a highly centralized planned economy ranking among the world’s most impoverished nations to a socialist-oriented market economic power house, currently ranking highest among the world’s largest growth economies. Throughout this transition Vietnam has struggled with food security in which concerns have shifted from ‘is there enough to eat?’ to ‘is it safe to eat?’. Food safety has become a major social and political issue in Vietnam. Urbanization puts pressure on the provision of daily fresh food. The distanciation of production-consumption relationships and the intensification of cultivation methods, as a response to growing urban demand with a declining farmland acreage, results in regular food safety incidents related to the inappropriate use of chemicals in agricultural production. The wide media coverage of such incidences has resulted in food safety being the ‘number one consumer concern’ in Vietnam.

    To improve food safety and to restore trust among consumers, authorities in Vietnam, as in other parts of Asia, promulgate policies that focus on the modernization of the food retail system. Western models of consumption and retailing strongly influence these retail modernization policies, placing supermarket development at the core of strategies. The retail modernization policies are designed to influence choices and persuade consumers to change their behavior based on the idea that consumers make rational choices, assuming that food safety concerns will drive consumers into supermarket channels. However, despite consumer food safety concerns, in the performance of everyday life, consumers don’t ‘en masse’ adopt the policy enabled risk-reducing alternative of supermarkets. Traditional channels such as wet markets continue to dominate in the daily fresh vegetable purchasing practices. This phenomenon is observed across the Asian continent. As it turns out, transitions in the food buying practices of Asian consumers are not so easily established.

    This thesis addresses consumption as a social practice. The application of social practice based approaches to the analysis of consumption started around the turn of the century and has since gained importance in thinking about food system changes with a strong focus on western developed societies. By applying the research on the specific case of shopping for vegetables in Vietnam, this thesis exemplifies how a social practices approach is relevant beyond OECD countries. In studying the relation and dynamics between local cultural tradition and advanced globalization at the consumption junction, this thesis uncovers how practices of shopping for vegetables and their inherent food safety dynamics emerge, evolve, or die out within the rapidly transforming urban context of Hanoi, Vietnam. This thesis is concerned with the question:

    How do ordinary people in Vietnam confront food safety risks and why and how they do, or do not adopt alternative practices, like modern retail shopping, to respond to their increasing concerns about the fresh-food made available to them?

    The conducted research and its findings are described in this thesis over six chapters. It starts with an introductory chapter 1, followed by four distinct, though coherent, empirical research chapters (chapter 2-5). Each of these chapters delivers a complementary understanding on the everyday practice of shopping for vegetables in the transformative context of Vietnam. Combined these empirical research chapters provide an understanding of how practices of shopping for vegetables develop, are sustained and/or die out within a rapidly transforming urban context. The thesis ends with a concluding chapter 6.

    The first chapter describes the research problem, the theoretical framing of the problem and the research questions. The chapter explicates why this thesis takes a social practices theory based research approach. Exploring the middle ground of two interlinked debates - a debate with extreme positions in retail development and a debate on how to bring about behavioral change, - it is discussed that a social practices approach is relevant for obtaining understandings of everyday life, because of its non-individualist perspective, its empirical focus on habitual activity, and its inclusion of the local context. Next, the chapter outlines the conceptual approach in which relations between provision systems on the one hand and consumers on the other are mediated at the food retailing sites. By giving primacy to neither agency nor structure, it is discussed how practices based research, might deliver an understanding of the relation and dynamics between local cultural tradition and advanced globalisation. It than elaborates on the novel programmatic methodological approach of shifting perspectives - zooming in on situated practices and zooming out through a historical mapping of a portfolio of embedded practices - that allow the detection of the dynamics in situated habitual and contextually constrained activities, as well as longer term transformations of practices over time. Chapter 1 concludes with an exposition of the mix of methods applied.

    Chapter 2 investigates which characteristics of the dominant and persistent practice of shopping at wet markets account for its continued reproduction and addresses the question of how food safety concerns are confronted within this well–established practice. Taking a rural city not yet touched by retail modernization as the research setting, this chapter presents in-depth empirical research insights on interactions at wet-market from the perspective of both sales persons and citizen-consumers. This chapter shows that food safety is a well-recognized dilemma by both providers and consumers of vegetables, but that food safety concerns are not the principal factor in determining the purchasing practices. Shopping at wet markets is a highly routinized taken for granted activity and food safety concerns only become prominent within this habitual shopping setting. Deploying specific heuristics for vendor and product selection, food safety is shown to be continuously reproduced along pre-given lines. As long as the existing, ‘practical’ repertoire of food safety heuristics deployed by consumers suffices in counter balancing their anxieties, consumers adhere to their established food shopping routines of shopping at wet markets.

    Chapter 3 explores the persistence of shopping for vegetables at informal, uncontrolled, and unhygienic street markets in the context of advancing retail modernization in urban Hanoi. Government induced policies aim at replacing wet markets by supermarkets and therewith enforce breaks with well-established routines. However, although supermarkets are recognized and valued as safe vegetable retailing sites, they are only marginally successful in attracting daily vegetables consumers. This chapter addresses the question of what context specific processes and circumstances account for the continued reproduction of shopping at street markets that do not offer formal food safety guarantees. The empirical study of vegetable shopping practices at six different street markets, reveals how consumers handle food safety concerns in combination with other choices about where and when to buy. It shows how and why daily routines are time-spatial constrained. Where and how to buy vegetables is importantly shaped by other activities in daily life. The empirical research illustrates that temporal and spatial dimensions of practices in contemporary daily life in Hanoi constitute a reinforcing mechanism for the persistence of uncontrolled and unhygienic street markets, rather than the uptake of supermarkets. This chapter points out that food safety policies and interventions that do not take into consideration the existing everyday consumption practices, might fail to address acute food safety issues.

    Chapter 4 assesses the extent of the outreach of modernized retail formats in terms of who benefits, who is excluded and what context specific processes and circumstances influence the uptake of modified or modern retail formats by different social groups. A practice realist perspective is demonstrated to be relevant for addressing outreach and social inclusion and understanding how policy interventions play out in practice. On the basis of a collective case study of six distinct policy induced retail modernization interventions, this chapter illustrates the emerging and on-going process of food retail transformation. This approach exposes how and why similar supermarket interventions can yield contrasting intermediate outcomes when they do not accommodate for differences in shopper population and do not adapt to variations in the urban conditions. The current one-dimensional, supermarket oriented, retail modernization policy that aims to reduce the exposure to uncertified ‘unsafe’ food, is shown to lead to the exclusion of a large proportion of the population. This chapter points out the importance for Vietnamese policymakers to consider the risk of social deprivation and to explicitly reflect on the unanticipated consequences of the normative direction of their interventions in food provision. This chapter indicates that reaching a more diverse population requires more flexible policies that allow for malleability in response to local conditions.

    Chapter 5 addresses the questions: what practices of purchasing or appropriating fresh vegetables do exist in contemporary Vietnam; how do they relate to food safety concerns and dynamics; why did they emerge and evolve during the past 40 years; and what factors are important in explaining the dynamics of change in the overall set of shopping practices? Deploying a practice historical perspective, this chapter unravels the complex evolving relationships between the local and the global as they can be read from the ways in which Vietnamese consumers deal with food safety risks when shopping for fresh food, by analyzing a portfolio of shopping practices against the background of historical changes over the period 1975-2015. Discussing the way in which six situated social practices are embedded in the broader set of food appropriation practices, this chapter portrays how practices show consistency in change over time, influenced by transformations in their environment, in which practices are interrelated with other practices in daily life beyond the act of shopping for food and beyond the domain of food. Further this chapter demonstrates how food safety related trust mechanisms as deployed by Vietnamese consumers show patterns of hybridization of personalized trust with abstract guidance systems. The historical approach provides insights on why shopping at supermarkets is not just currently still limited in recruiting practitioners. Also looking forward, it is not reasonable to expect homogenization in food retail system transformation.

    This thesis concludes with chapter 6 which addresses the question of what lessons can be learned from social practices research in assessing the present and future role of supermarkets and the accompanying food safety strategies, which imply the de- and re-routinization of well-established contemporary practices of shopping for fresh-food. Along the four empirical research chapters, it first sets out to answer the research questions. Next it elaborates on the theoretical and methodological approach. The chapter describes the iterative research process and depicts how methodological variance can be used as a strength when applied as an intelligible program of shifting perspectives - zooming in and out on practices - and a mix of methods. It is pointed out that although practices based approaches are criticized on their complexity and ambiguity, the approach used in this thesis is proven to deliver concrete results and might be useful in similar cases. Lastly, this concluding chapter discusses how practices based perspectives have the potential to inform a more versatile and amenable portfolio of public regulations and resources when striving for amelioration in food provision, not only in Vietnam, but across the Asian continent.

    This thesis demonstrates how changes in infrastructures are not sufficient for changing practices and thus warns against making food safety policies strongly dependent on a single supermarket model. Instead of putting all strategic resources on one strategy, efforts of integration and mutual adaptation of modern and traditional structures could be considered. Pursuing a trend of hybridization prevents that consumers have to break with long established routines in an isolated, radical way.

    PermVeg: a generic tool to design and assess crop rotations for permanent vegetable production systems; User manual
    Wassink, B. ; Berg, W. van den; Putter, H. de; Hengsdijk, H. - \ 2015
    Wageningen : Wageningen UR (vegIMPACT report 9) - 10
    rotatie - groenteteelt - computersimulatie - simulatiemodellen - handbediening - vietnam - indonesië - rentabiliteit - arbeidskosten - pesticiden - handleidingen - rotation - vegetable growing - computer simulation - simulation models - manual operation - vietnam - indonesia - profitability - labour costs - pesticides - guide books
    This manual describes a generic tool to design and assess alternative vegetable rotations. The model combines vegetable crops to generate all possible crop rotations for a given period, based on a number of explicit criteria (objectives and restrictions) controlled by the user. The criteria eliminate in early stages those crop rotations that are undesirable. The criteria relate among others to the most important socio-economic and environmental factors in vegetable production, i.e. profitability, labor requirements and costs of pesticide use.
    Spatial and seasonal diversity of wild food plants in home gardens of Northeast Thailand
    Cruz Garcia, G.S. ; Struik, P.C. - \ 2015
    Economic Botany 69 (2015)2. - ISSN 0013-0001 - p. 99 - 113.
    tropical homegardens - west-bengal - system - weeds - biodiversity - management - resources - medicine - vietnam - mexico
    Wild food plants (WFPs) are major components of tropical home gardens, constituting an important resource for poor farmers. The spatial and seasonal diversity of WFPs was analyzed across multi-species spatial configurations occurring within home gardens in a rice farming village in northeast Thailand. Data were collected in 77 sampling sites corresponding to five different home garden spatial configurations, namely fenced plot, fenced plot margin, yard, home garden boundary, and pot. Absolute abundance and frequency of occurrence were quantified per individual WFP species in both dry and rainy seasons, and data on additional uses (besides food) were collected through focus group discussions for each WFP species. A total of 20 species corresponding to 13 botanical families were reported. Results show that species abundance and frequency of occurrence varied seasonally and spatially within home gardens. Diversity, as observed in the analysis of Shannon and Simpson diversity indexes, also differed seasonally and across different spatial configurations. Home gardens showed higher diversity in the dry season because of the presence of human management. Ninety-five percent of the WFP species presented additional uses, with nine different types of uses in total. Finally, as this study demonstrates, the results on both the spatial and seasonal diversity of WFPs over different spatial configurations comprise a new perspective in home garden research by providing new understandings about their composition and management.
    Antibody response and risk factors for seropositvity in backyard poultry following mass vaccination against highly pathogenic avian influenza and Newcastle disease in Indonesia
    McLaws, M. ; Priyono, W. ; Bett, B. ; Al-Qamar, S. ; Claassen, I.J.T.M. ; Widiastuti, T. ; Poole, J. ; Schoonman, L. ; Jost, C. ; Mariner, J. - \ 2015
    Epidemiology and Infection 143 (2015)8. - ISSN 0950-2688 - p. 1632 - 1642.
    domestic poultry - h5n1 - ducks - surveillance - countries - efficacy - vaccines - vietnam - viruses - field
    A large-scale mass vaccination campaign was carried out in Java, Indonesia in an attempt to control outbreaks of highly pathogenic avian influenza (HPAI) in backyard flocks and commercial smallholder poultry. Sero-monitoring was conducted in mass vaccination and control areas to assess the proportion of the target population with antibodies against HPAI and Newcastle disease (ND). There were four rounds of vaccination, and samples were collected after each round resulting in a total of 27 293 samples. Sampling was performed irrespective of vaccination status. In the mass vaccination areas, 20–45% of poultry sampled had a positive titre to H5 after each round of vaccination, compared to 2–3% in the control group. In the HPAI + ND vaccination group, 12–25% of the population had positive ND titres, compared to 5–13% in the areas without ND vaccination. The level of seropositivity varied by district, age of the bird, and species (ducks vs. chickens).
    Climate proofing aquaculture: a case study on pangasius farming in the Mekong
    Anh, L.N. - \ 2014
    Wageningen University. Promotor(en): Johan Verreth; Rik Leemans; S. De Silva, co-promotor(en): Roel Bosma. - - 126
    aquacultuur - zoetwatermeervallen - zoetwateraquacultuur - zeeniveau - klimaatverandering - zoutwaterindringing - mekong - vietnam - aquaculture - freshwater catfishes - freshwater aquaculture - sea level - climatic change - salt water intrusion - mekong river - vietnam

    Abstract

    Vietnam is among the top five countries that will be most affected by sea level rise. This study aimed to assess the subsequent impacts of flooding and salinity intrusion on, and to evaluate suitable adaptation strategies for the Mekong Delta's pangasius farming sector.

    Water level rise and salt water intrusion for three sea level rise (SLR) scenarios (i.e. +30cm, +50cm and +75cm) were simulated by using the MIKE11 model. The results showed that at SLR+50, the 3m flood level would spread downstream and threaten farms located in upstream and midstream regions. Rising salinity for SLR+75 would reduce the appropriate time-window for the culture in coastal areas.

    A Chi-Square test and a logit regression model were employed to examine factors which influence pangasius farmers’ perception of and adaptation to climate change impacts. Less than half of the respondents were concerned about climate change and actively sought suitable adaptation measures to alleviate its impacts. The adaptive capacity of pangasius farmers can be improved by increasing the information on climate change and introducing early warning systems.

    The technical efficiency (TE) of randomly sampled pangasius farms was estimated using Data Envelopment Analysis, and factors affecting technical and scale efficiency were examined with bootstrap truncated regression. The mean TE score assuming constant return to scale was 0.66, and under variable return to scale it was 0.84. TE of downstream farms was higher compared to the upstream and midstream farms due to lower energy costs and stocking once a year at a lower density, but these reduced the scale efficiency of farms affected by salinity intrusion. Upstream and midstream farms needed to pump water and stocked at least three times in two years. Regression analysis showed a positive effect on TE of the farmer’s education level, and of having experienced climate change impact through flooding or salinity intrusion in the past.

    Using a decision tree framework, this study analyzed possible options for adapting pangasius farming to the projected climate-change impacts. Options to adapt to salinity intrusion are: modify the pangasius farming practice by using e.g. water recirculation systems, stock other species, or stock saline-tolerant pangasius with support from research and extension. A breeding program for saline-tolerant striped catfish requires long-term investments (0.4 % of the present production costs). To adapt to worse flooding, pangasius farms not located within the upgraded government dyke-protected areas could raise the height of the dyke around their pangasius farm, which would increase the total variable costs per ha for one harvest by about 0.34% in the upstream and midstream regions, and by 0.25% in the downstream region.

    Hypertension in Vietnam: prevalence, risk groups and effects of salt substitution
    Do, H.T.P. - \ 2014
    Wageningen University. Promotor(en): Edith Feskens; Frans Kok, co-promotor(en): Marianne Geleijnse. - Wageningen : Wageningen University - ISBN 9789462571372 - 159
    hypertensie - risicogroepen - risico - gezondheid - zout - vervangmiddelen - voeding - levensstijl - vietnam - hypertension - risk groups - risk - health - salt - substitutes - nutrition - lifestyle - vietnam

    ABSTRACT

    Background: Over the past decades, the morbidity and mortality patterns have changed rapidly in Vietnam, with a reduction in infectious diseases in parallel with a rapid increase in non-communicable diseases (NCDs), leading to the so-called double burden. It was estimated that in 2008 NCDs accounted for 75% of all deaths in Vietnam, and cardiovascular diseases were the leading cause accounting for 40% of total mortality. Hypertension is one of the major risk factors for cardiovascular disease, but information on the nationwide prevalence and main determinants is lacking. There is an urgent need for appropriate population-based interventions for hypertension control and prevention in Vietnam.

    Methods and Results: Data of 17,213 adults aged 25-64 years from the nationally representative 2005 National Adult Obesity Survey were used to study the prevalence of hypertension and prehypertension and their determinants. The overall prevalence of hypertension was 20.7% and the prevalence of prehypertension was 41.8%. Hypertension and prehypertension were more prevalent in men than in women (25.2% vs. 15.9%). Determinants of raised blood pressure including advancing age, overweight, alcohol use (among men), and living in rural areas (among women) were independently associated with a higher prevalence of hypertension, whereas higher levels of physical activity and education were inversely associated. Age, body mass index (BMI), and living in rural areas were independently associated with an increased prevalence of prehypertension. Among the hypertensives, only 25.9% were aware of having hypertension and 12.2% were treated. Among the treated hypertensives, 32.4% had their blood pressure controlled.

    Overweight and obesity, important risk factors for hypertension, were investigated using data of 14,452 Vietnamese adults aged 25-64 years from the nationally representative 2000 National Nutrition Survey and data of 17,213 adults aged 25-64 years from the nationally representative 2005 National Adult Obesity Survey. The results showed that the distribution of BMI across the population and in population subgroups indicated a shift towards higher levels in 2005 as compared to 2000. The nationwide prevalences of overweight (BMI ≥ 25 kg/m2) and obesity (BMI ≥ 30 kg/m2) were 6.6% and 0.4% respectively in 2005, almost twice the rates of 2000 (3.5% and 0.2%). Using the Asian BMI cut-off of 23 kg/m2 the overweight prevalence was 16.3% in 2005 and 11.7% in 2000. Women were more likely to be both underweight and overweight than men in both 2000 and 2005. Urban residents were more likely to be overweight and less likely to be underweight as compared to rural residents in both years. The shifts from underweight to overweight were more pronounced in those with higher food expenditure levels.

    A survey on sodium intake among a rural community near Hanoi (n=121) showed that mean 24-hour sodium excretion was 188.6 ± 57.5 mmol (4.3g), which corresponds to an intake of salt (sodium chloride) of 10.8 ± 3.3 g/day. Men had a higher mean sodium excretion (196.8 ± 56.9 mmol/day or 4.5g/day) than women (181.1 ± 57.4 mmol/day or 4.2g/day); 97.5% of the men and women had a salt intake higher than the World Health Organization’s recommendation of < 5g/day. Subjects with complete urine collection had a salt excretion of 11.7 g/day. Sodium in condiments added during cooking or eating at the table accounted for 81% of sodium intake. Processed foods contributed 11.6% and natural foods 7.4%. Regarding the condiments, the largest source was the mixed seasoning (35.1% of total); 31.6% of total dietary sodium was provided by fish sauce, 7.4% by monosodium glutamate and 6.1% by table salt.

    Sodium-reduced and potassium-enriched salt and ‘bot canh’, a traditional seasoning, were experimentally produced and underwent organoleptic testing, which showed high acceptance. An 8-week randomized double-blind trial was carried out in 173 men and women between 45 and 64 years of age with untreated (pre)hypertension in a rural Vietnamese community. The intervention group that received sodium-reduced and potassium-enriched condiments (salt and bot canh) experienced a median 24-hour sodium excretion decrease of 28.5 mmol/d (1.6 g/d salt) compared to the control group that received regular condiments for home food preparation and dining. The mean change in BP in the intervention compared to the control group was -2.6 mmHg (95% CI: -4.6 to -0.5, p = 0.013) for systolic BP and -1.6 mmHg (95% CI: -3.0 to -0.2, p= 0.024) for diastolic BP. The prevalence of iodine deficiency was significantly reduced in both groups (from 66% to 41% in the intervention group and from 72% to 36% in the controls).

    Conclusion: Hypertension and prehypertension are prevalent in Vietnam, but awareness, treatment, and control are low. Lifestyle modifications, including the prevention of overweight, and the promotion of physical activity, particularly in urban areas, and the reduction of high alcohol consumption in men, may help to prevent hypertension in Vietnam. Between 2000 and 2005, BMI in the population shifted towards higher levels, especially in those with higher food expenditure levels, but under nutrition was also still prevalent in 2005. Most dietary sodium (81%) comes from adding salty condiments during food preparation or at the table. Therefore, limiting condiments added during cooking and at the table should be given priority. Alternatively, regular condiments may be replaced with sodium-reduced and potassium-enriched salt and ‘bot canh’ to lower BP in (pre)hypertensive Vietnamese adults. Salt iodization should be reconsidered to ensure adequate iodine intake of the population.


    TABLE OF CONTENTS

    Chapter 1

    General introduction

    1 - 24

    Chapter 2

    National prevalence and associated risk factors of hypertension and prehypertension among Vietnamese adults.

    American Journal of Hypertension, Epub ahead of print 2014/05/28

    25 - 44

    Chapter 3

    Nationwide shifts in the double burden of overweight and underweight in Vietnamese adults in 2000 and 2005: two national nutrition surveys.

    BMC Public Health 2011, 11:62

    45 - 66

    Chapter 4

    Sodium intake and its dietary sources in Vietnamese rural adults

    Submitted

    67 - 80

    Chapter 5

    Sodium-reduced and potassium-enriched condiments reduce sodium intake and blood pressure in Vietnamese adults: a randomized controlled trial.

    Submitted

    81 - 100

    Chapter 6

    General discussion

    101 - 120

    Summary

    Summary in Dutch

    Summary in Vietnamese

    Acknowledgment

    About the author


    The governance capacity of forest land allocation policy in Vietnam
    Thi Kim Phung, D. - \ 2014
    Wageningen University. Promotor(en): Bas Arts, co-promotor(en): Ingrid Visseren-Hamakers. - Wageningen : Wageningen University - ISBN 9789462570740 - 201
    bosbeleid - bosbouw - governance - overheidsbeleid - toewijzing - vietnam - forest policy - forestry - governance - government policy - allocation - vietnam

    The issue of what drives and sustains collective action is pertinent to natural resource management, given the continuing depletion of public goods around the world. The issue is especially important for forestry. Since the early 1980s, forest devolution has become a major trend in forestry reforms in the developing world. It is held that involving local people in forestry and enabling them to benefit from forests will generate sustainable forest management. However, the devolution of forest rights from the central state to local actors has had varied effects. This disparity has inspired a great volume of literature on factors behind the effects of forest devolution. However, there is still a lack of knowledge of various governance aspects in forest devolution processes, and particularly of how actors define the collective goals, how they interact and what their strategies in forest devolution are.

    The research presented in this thesis contributes to filling these knowledge gaps by studying a specific forest devolution policy, namely the policy of forest land allocation (FLA) in Vietnam. By involving local people in forestry, the policy is expected to improve both forest condition and local livelihoods. Although a considerable number of studies have provided insights into the effects of FLA, they were mainly carried out in the central highlands and northwest uplands of Vietnam and focused on forest-related factors. Not much attention has been paid to governance in the FLA policy. Although studies have paid attention to local people in the policy, local perspectives on the policy have not been thoroughly examined.

    The overall aim of the present study was to gain in-depth knowledge of the effects of the FLA policy by assessing its governance capacity in different regions of Vietnam. Since what constitutes governance capacity is still under discussion in the governance literature, the secondary aim was to develop a framework for assessing the governance capacity of the policy. The first research aim was operationalized into the following three research questions:

    How did the FLA policy in Vietnam come about, and to what extent did national forestry discourses influence the policy?To what extent has the FLA policy had the capacity to involve actors, particularly local people, in different regions of Vietnam; and what factors have determined this capacity?What has been the performance of the FLA policy in different regions of Vietnam, and what factors have determined this performance?

    To achieve the second research aim, a framework was developed to guide the assessment of governance capacity.

    The research employed the nested approach to case studies, which situates the FLA policy under the general case of Vietnam’s forestry reforms, which in the past 20 years have been characterized by changing forestry discourses. The case of the FLA policy includes three nested cases in three regions of Vietnam (southeast lowlands, central highlands and northwest uplands). Fieldwork was carried out in three provinces (Tay Ninh, Dak Lak and Lao Cai). Data collection included a literature review, document analysis, semi-structured interviews, a questionnaire survey and personal observations. In total, 152 key informants were selected by snowball and saturation sampling. These informants were policy and decision makers, officials in forestry and land management sectors, representatives of provincial governments and local authorities, forest owners and forestry contractors, and local villagers. The survey involved 288 forestry contractors or forest owners. Data from different sources was triangulated before processing. The method of Miles and Huberman (1984) was applied to analyze qualitative data. Simple statistics with frequencies and cross tabulation were employed to analyze data from the questionnaires.

    This thesis consists of six chapters. Chapter 1 provides an overview of the thesis. Chapter 2 analyzes the discursive background against which the FLA policy has been developed. The framework that was developed to guide the assessment of the governance capacity of the FLA policy is presented in Chapter 3. The framework is based on the theoretical perspectives of the policy arrangement approach. Governance capacity consists of institutional capacity – namely the degree to which rules and procedures enable actors to work together in order to solve collective problems – and governance performance, that is, whether a policy arrangement actually achieves collective goals. The framework consists of three elements: enabling rules of the game, converging discourses and facilitating resource mobilization. These elements are further operationalized as relevant aspects and criteria for the assessment of the governance capacity of the FLA policy. Institutional capacity is assessed in terms of four criteria: codification of rights, venues, open attitudes and resource availability. Governance performance is evaluated according to four criteria: the practising of property rights, social learning, forest condition and contribution of the policy to local people’s income. Chapter 4 and Chapter 5 apply the framework to assess the governance capacity of the FLA policy. Chapter 6 synthesizes the study’s findings and presents theoretical and methodological reflections on forest devolution and governance capacity

    The thesis yields in the three key conclusions on the governance capacity of the FLA policy in Vietnam. First, the two national forestry discourses, namely forestry socialization and sustainable forest management, under Vietnam’s forestry reforms since 1991, have shaped the development of the FLA policy over the past 20 years. By maintaining the leading role state actors in forest land allocation, they advocate the restricted access to forest lands and limited property rights of non-state actors involved in the policy. Second, the institutional capacity of the FLA policy is low because of the limited codification of rights, rather symbolic venues for actors’ deliberation, local people’s low interest in forest rehabilitation, and the limited availability of forests, funding and information for forest rehabilitation. Third, trade-offs between the achievement of the two policy goals (improving the forest condition and local incomes from forests) have shaped the low governance performance of the FLA policy. These trade-offs result from the combined influences of social learning and property rights on actors’ cooperation in the policy. On the basis of these conclusions, the thesis goes on to discuss the key factors that determine the effects of forest devolution (property rights, social learning and external factors), and the interlinkage between the institutional capacity and governance performance of FLA policy. The thesis then evaluates the strengths, shortcomings, and applicability the governance capacity framework. After reflecting on the research methods used in the study, the thesis draws out policy implications for the FLA policy and forest devolution. Besides the improvements of property rights, clear shared responsibilities of actors involved are crucial to promote more active involvement of non-state actors, particularly local people. Local meetings should facilitate a true deliberation that allow actors to reach some reconciliation concerning the collective goals. Other technical and policy measures to improve the values of forests (such as NTFPs and environmental services) are of special importance to sustain and increase actors’ income from forests. Macro policy planning should pay more attention to the possible trade-offs among different land uses and frequent reviews and revisions of the policy are necessary to keep up with changes in both the broader socioeconomic contexts and the local conditions. For forest devolution, the institutional design of forest devolution should take into consideration not only property rights but also other governance issues, and encompass both substantive and organizational aspects of forest devolution. More attention should be paid to the combined impacts of property rights and social learning on resource uses and resource conservation. Especially, the thesis shows that the changing governance in forest devolution is not a ‘hollowing out’ of the state in forestry. State actors both at the central and provincial levels still play important roles in forest devolution.

    Constrained consumer practices and food safety concerns in Hanoi
    Wertheim-Heck, S.C.O. ; Vellema, S. ; Spaargaren, G. - \ 2014
    International Journal of Consumer Studies 38 (2014)4. - ISSN 1470-6423 - p. 326 - 336.
    consumption - supermarkets - vietnam - policy
    Food safety is a widely recognized concern in Vietnam. Public officials, companies and consumers find different ways to address risks of pesticide residues and bacterial contamination related to the use of fresh vegetables in daily diets. The response of the government to these food safety risks includes the modernization and regulation of the food retail system. However, reforms that aim to offer a controlled and predictable provision of fresh vegetables through supermarkets seem to contrast with the daily consumer practices in a dynamic city as Hanoi; over 95% of vegetables is still being purchased at long-established open-air markets, importantly the informal and unhygienic street markets. Using a practices theory approach, this paper aims to explain this persistence of street-market shopping for vegetables. Detailed accounts of consumer practices, case studies at different retailing sites and daily logbooks of consumers demonstrate that the way consumers cope with food safety risks is largely shaped by the temporal and spatial constraints of their daily shopping practices. We identified how vegetable shopping is either enjoyed as social interaction within the local community or is regarded a time-consuming activity that conflicts with other activities in everyday life. Our findings indicate how these constraints constitute a reinforcing mechanism for the persistence of uncontrolled and unhygienic street markets. To make policy responses to food safety risks both more realistic and effective, it is essential to connect to and accommodate the daily realities of consumers managing time and space in a modernizing city rather than to impose an ideal, typical market exclusively driven by the wish to control food safety risks.
    Designing and testing permanent vegetable production systems for the Red River Delta, Vietnam
    Pham Thi Thu Huong, Huong - \ 2014
    Wageningen University. Promotor(en): Paul Struik, co-promotor(en): Arij Everaarts; Jacques Neeteson. - Wageningen : Wageningen University - ISBN 9789461738936 - 170
    groenteteelt - groenten - teeltsystemen - gewasbescherming - chemische bestrijding - rentabiliteit - arbeidsvereisten - vietnam - vegetable growing - vegetables - cropping systems - plant protection - chemical control - profitability - labour requirements - vietnam
    Transmission of fish-borne zoonotic trematodes (Heterophyidae) to common carp (Cyprinus carpio) is independent of density of fish and trematodes
    Boerlage, A.S. ; Graat, E.A.M. ; Verreth, J.A.J. ; Jong, M.C.M. de - \ 2014
    Journal of Helminthology 88 (2014)2. - ISSN 0022-149X - p. 183 - 188.
    diplostomum-spathaceum - centrocestus formosanus - haplorchis pumilio - cercariae - host - infection - vietnam - recognition - populations - aquaculture
    Fish-borne zoonotic trematodes (FZTs) can cause major human health problems. The aim of this study was to quantify the transmission of parapleurolophocercous cercariae to common carp (Cyprinus carpio) and to study the effect of the density of cercariae and the density of fish on transmission with respect to the volume of water and surface area of the bottom. Fish were kept individually either as controls (n= 91) or were exposed to 250 cercariae in tubes with a volume of 25, 50, 100, 250 or 500 ml water (n= 190) with a surface area of 4, 12, 21, 30 or 49 cm2 (n= 195). The dose to which the fish were exposed was kept constant. Infection occurred in 94–100% of fish, with a mean of 15–18 metacercariae per fish and the proportion of FZTs established at 0.06–0.07 metacercariae per cercariae per fish. Neither the prevalence of infection with FZTs nor the number of metacercariae per fish nor the proportion of FZTs established were significantly associated with differences in the density of cercariae or the density of fish per ml water or per cm2 surface area. Thus, it was concluded that the transmission of cercariae to fish is independent of density.
    Effect of control strategies on the persistence of fish-borne zoonotic trematodes: A modelling approach
    Boerlage, A.S. ; Graat, E.A.M. ; Verreth, J.A.J. ; Jong, M.C.M. de - \ 2013
    Aquaculture 408-409 (2013). - ISSN 0044-8486 - p. 106 - 112.
    clonorchis-sinensis - haplorchis-pumilio - epidemic models - cyprinus-carpio - life-cycle - heterophyidae - populations - vietnam - transmission - computation
    Fish-borne Zoonotic Trematodes (FZTs) are a risk to human health and need to be controlled. A mathematical model was developed to give insight into how and to what extent control strategies change the dynamics of FZTs on integrated agriculture–aquaculture farms. The reproduction ratio R evaluates the effects of control strategies. R > 1 implies that the infection may persist, whereas R <1 implies that the infection certainly cannot persist. In the absence of control strategies (default), R = 1.92. After implementing control strategies either (i) R and percentages infected hosts in the equilibrium did not change and FZTs persisted (ii) R became smaller, but not below 1, the new equilibrium had lower proportions of infected hosts, and FZTs persisted, or (iii) R became smaller than 1, and all hosts were FZT-free in the new equilibrium. Single chemotherapy of humans, reservoir hosts or both did not change R. Continuous chemotherapeutic treatment reduced R but not below 1 when treating only humans (R = 1.30) or only reservoir hosts (R = 1.69). A combination could result in R <1, e.g. treating all humans and > 54% of reservoir hosts. Snail control could result in R <1 with a decrease in density or increase in mortality of snails. This will occur when either transmission to snails or to fish is <14% of its default value. Stocking fish at > 25 g as compared to 0.5 g that is usual in aquaculture practice, or at > 14 g in combination with treating all humans, led to R <1. Advantage of using R for evaluating control strategies is that it provides insight into control success or failure even if it would take several decennia to observe this effect in the field.
    Risk factors for the presence of Aedes aegypti and Aedes albopictus in domestic water-holding containers in areas impacted by the Nam Theun 2 hydroelectric project, Laos
    Hiscox, A.F. ; Kaye, A. ; Vongphayloth, K. ; Banks, I. ; Piffer, M. ; Khammanithong, P. ; Sananikhom, P. ; Kaul, S. ; Hill, N. ; Lindsay, S.W. ; Brey, P.T. - \ 2013
    American Journal of Tropical Medicine and Hygiene 88 (2013)6. - ISSN 0002-9637 - p. 1070 - 1078.
    dengue vector control - diptera-culicidae - singapore-city - mosquitos - l. - insecticide - thailand - vietnam - skuse - surveillance
    We assessed risk factors for vectors of dengue and chikungunya viruses near a new hydroelectric project, Nam Theun 2, in Laos. Immature stages of Aedes aegypti were found only in sites within 40 km of the urban provincial capital, but Aedes albopictus was found throughout. Aedes aegypti pupae were most common in water storage jars (odds ratio [OR] = 4.72) and tires (OR = 2.99), and Ae. albopictus pupae were associated with tires in 2009 (OR = 10.87) and drums, tires, and jars in 2010 (drums OR = 3.05; tires OR = 3.45, jars OR = 6.59). Compared with water storage vessels, containers used for hygiene, cooking, and drinking were 80% less likely to harbor Ae. albopictus pupae in 2010 (OR = 0.20), and discarded waste was associated with a 3.64 increased odds of infestation. Vector control efforts should focus on source reduction of water storage containers, particularly concrete jars and tires.
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