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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    Analysis of a monitoring system for bacterial wilt management by seed potato cooperatives in Ethiopia: Challenges and future directions
    Tafesse, Shiferaw ; Lie, Rico ; Mierlo, Barbara van; Struik, Paul C. ; Lemaga, Berga ; Leeuwis, Cees - \ 2020
    Sustainability 12 (2020)9. - ISSN 2071-1050
    Bacterial wilt - Collective action - Disease management - Monitoring system - Seed cooperatives

    Collective action is required to deal with various complex agricultural problems such as invasive weeds and plant diseases that pose a collective risk to farmers. Monitoring systems could help to stimulate collective action and avoid free-riding. The paper develops a novel framework consisting of essential elements of a monitoring system for managing a complex disease like bacterial wilt in potato crops. The framework is used to explore how seed potato cooperatives in Ethiopia operationalised the essential elements of a monitoring system and identifies which challenges remain to be overcome. Data were collected through in-depth interviews, reflective workshops, participant observation, and document analysis. We found that the cooperatives had organised a self-monitoring system to monitor disease occurrence and the disease management practices of their members. Monitoring committees were in charge of the data collection and enforcement of sanctions on farmers who did not adhere to the cooperatives- bylaws. The main challenges included the dependency on visual observation, which does not disclose latent infections, limited financial incentives for the monitoring committee members, lack of trust, weak peer monitoring, and the social and ecological interdependency between producers of ware and seed potatoes. Suggestions are provided to strengthen the monitoring systems of farmers- seed potato cooperatives in Ethiopia. In addition, we discuss the broader value of our novel framework for describing and analysing monitoring systems for future research and intervention.

    The practice of informal tourism entrepreneurs: a Bourdieusian perspective
    Çakmak, Erdinç - \ 2020
    Wageningen University. Promotor(en): C. Leeuwis, co-promotor(en): R. Lie; T. Selwyn. - Wageningen : Wageningen University - ISBN 9789463952309 - 204

    Informal economies have been growing, in particular, in the developing world. Nearly two-thirds of the world’s employed population earn their livelihoods in the informal economies. The informal economy entrepreneurs provide essential products and services, enhance supply chains, generate employment, and contribute substantially to the economic and social life of communities worldwide. However, the views of informal entrepreneurs have often been marginalized and the issues affecting them are frequently left unobserved in academic or professional debates. Little is known about the informal tourism economy’s characteristics in the existing literatures and so far, no study has estimated the size of the informal tourism economy. Yet, the informal tourism entrepreneurs enter into tourism markets with important skills, qualities, and attributes - in the forms of economic, social, cultural, and dream capitals - which could be utilized more successfully to enable them to contribute to broader economic development initiatives.

    This PhD-thesis, based on in-depth empirical research, investigates how informal tourism entrepreneurs co-construct their informal tourism sector through their practices. Using an interdisciplinary approach (e.g. mainly sociological and anthropological perspective but also an economic one), this PhD-thesis sees the informal sector as a social system in which people continuously shape and reshape their livelihoods, individually and collectively. More specifically, this PhD-thesis investigates how evolving conditions in the tourism field and beyond simultaneously affect the capital deployment and habitus adaptations of informal tourism entrepreneurs and uses the macroeconomic indicators to estimate the size of the informal tourism economy and its relations to the general economy. Accordingly, this PhD-thesis consists of three chapters that depart from an anthropological/sociological perspective, but also includes one chapter that departs from a fundamentally economic perspective. In seeking answers to the research questions, this PhD uses Bourdieu’s theory of practice and creates understanding by

    1. Contrasting the networks of social relations in the field, where informal tourism entrepreneurs take positions or struggle over capital, stakes, and access,

    2. Comparing the different forms of capital owned by informal tourism entrepreneurs, and by

    3. Compiling insights from analyses of informal tourism entrepreneurs’ habitus.

    The methodologies adopted in these three chapters are narrative inquiry, discursive thematic analysis and ethnographic field research. In addition, the PhD-thesis consists of a fourth economic chapter and aims to incorporate an economic perspective within a social constructivist approach. Here the attention is paid to macroeconomic indicators and the chapter aims to estimate the size of the informal tourism economy and to advance understanding by evaluating the dynamic interplay between the informal tourism economy and the labour market. The four chapters together thus seek to offer a comprehensive and rigorous analysis of the practice and size of the informal tourism economy.

    Thailand is chosen as a context since it is the second largest economy in Southeast Asia, yet with the highest ratio of revenue arising out of the informal economic sector. The primary data has been collected at four different tourist destinations, namely Chiang Mai, which is the second largest city of country, and the top three most popular tourist islands - Koh Samui, Koh Phangan, and Koh Tao - located in the south of Thailand.

    This PhD-thesis contributes to academics and practitioners in several ways. First, this PhD-thesis offers interventions and hands-on actions to policy makers and destination governors rather than thinking the whole phenomenon holistically and/or analysing it as a set of significations and discourses. Second, it demythologizes the common sense view that informal entrepreneurs are marginalized, traditional, underdeveloped and backward entities, and shows empirically that informal tourism entrepreneurs have important and relevant capitals (e.g. skills, qualities, attributes, and networks), and contribute substantially to the socio-economic world of destinations in achieving their broader sustainable development goals. Third, this PhD-thesis addresses the evolution of informal tourism entrepreneurship from their role of poverty alleviation and survival strategy for unemployment in developing countries to their existence as trusted and socio-economically essential entities of the social system. It calls for inclusive frameworks and hybrid solutions in which informal entrepreneurs are recognised for their benefits to society in academic and professional debates.

    To this end, this PhD-thesis offers a more complete understanding of the practice of the informal tourism entrepreneurs and the informal tourism economy and its entrepreneurs’ contribution to national economies.

    Symposium review: Animal welfare in free-walk systems in Europe
    Blanco-Penedo, Isabel ; Ouweltjes, Wijbrand ; Ofner-Schröck, Elfriede ; Brügemann, Kerstin ; Emanuelson, Ulf - \ 2020
    Journal of Dairy Science 103 (2020)6. - ISSN 0022-0302 - p. 5773 - 5782.
    alternative housing - compost-bedded pack - dairy cow - welfare

    Providing more space per animal, soft bedding, and free roaming in animal housing systems is widely presumed to be beneficial for the welfare of the animals. This observational study aimed to investigate the basis of this assumption in free-walk housing systems (FWS) for dairy cows in Europe. The dairy cattle Welfare Quality assessment protocol was adapted for application to FWS, and the focus was on animal-based measures, from individual cow scoring to comfort around resting. The study was conducted on 41 farms [21 FWS and 20 cubicle housing (CH)] from 6 European countries (Germany, the Netherlands, Italy, Austria, Slovenia, and Sweden) displaying a variety of management systems. A total of 4,036 animals were scored. We found differences in animal welfare under different management conditions. The hindquarters and lower hind legs of cows from FWS were dirtier than those of cows in CH, but we found no difference in the dirtiness of udders or teats. Cows from FWS showed fewer hairless patches in all body areas except the neck; fewer lesions in the lower hind legs and hindquarters; and less swelling in the lower hind legs, flanks, and carpus than cows from CH. The prevalence of sound cows appeared to be higher in FWS, and moderate lameness prevalence was lower compared with CH. We found no difference in the prevalence of severe lameness between systems. We conducted a total of 684 observation sessions of comfort around resting, consisting of 830 lying down and 849 rising up movements. Cows in FWS took less time to lie down, had less difficulty rising up, and had fewer collisions with the environment during both behaviors than cows in CH. Cows lay partly or completely outside the supposed lying area less frequently in FWS than in CH. Cows in FWS adopted comfortable lying positions more often compared with CH, showing a higher occurrence of long and wide positions than cows in CH. Short positions were more common in FWS, and narrow positions were slightly more common in CH. We found large variations in animal-based measures between study herds and within housing systems. However, the observed patterns associated with each system demonstrated differences in cow scoring and comfort around resting. This study shows that a wide range of good and bad management practices exist in FWS, especially related to cow hygiene.

    Governing a Collective Bad: Social Learning in the Management of Crop Diseases
    Damtew, Elias ; Mierlo, Barbara van; Lie, Rico ; Struik, Paul ; Leeuwis, Cees ; Lemaga, Berga ; Smart, Christine - \ 2020
    Systemic Practice and Action Research 33 (2020). - ISSN 1094-429X - p. 111 - 134.
    Collective action - Communication - Crop disease - Late blight - Social learning

    There has been strong research interest in designing and testing learning approaches for enhancing and sustaining the capacity of communities to manage collective action problems. Broadening the perspective from well-known social learning approaches in natural resource management, this study explores how social learning as a communicative process influences collective action in contagious crop disease management. A series of facilitated discussion and reflection sessions about late blight management created the social learning space for potato farmers in Ethiopia. Communicative utterances of participants in the sessions served as the units of analysis. The study demonstrates how and to what extent social learning, in the form of aligned new knowledge, relations and actions occurred and formed the basis for collective action in the management of late blight.

    Contributions of experimental approaches to development and poverty alleviation : Field experiments and humanitarian assistance
    Quattrochi, John ; Aker, Jenny C. ; Windt, Peter van der; Voors, Maarten - \ 2020
    World Development 127 (2020). - ISSN 0305-750X

    The work of Nobel Laureates Banerjee, Duflo and Kremer has centered around the use of randomized control trials to help solve development problems. To date, however, few field experiments have been undertaken to evaluate the effects of humanitarian assistance. The reasons may lie in challenges related to logistics, fragility, security and ethics that often loom large in humanitarian settings. Yet every year, billions of dollars are spent on humanitarian aid, and policymakers are in need of rigorous evidence. In this paper, we reflect on the opportunities and risks of running experiments in humanitarian settings, and provide, as illustration, insights from our experiences with recent field experiments of large-scale humanitarian aid programs in the Democratic Republic of Congo.

    Securing Identities: Biometric Technologies and the Enactment of Human Bodily Differences
    Kloppenburg, Sanneke ; Ploeg, Irma van der - \ 2020
    Science as Culture 29 (2020)1. - ISSN 0950-5431 - p. 57 - 76.
    Biometrics - border management - enactment - ethnicity - identity

    Worldwide, biometrics are quickly becoming the preferred solution to a wide range of problems involving identity checking. Biometrics are claimed to provide more secure identification and verification, because ‘the body does not lie.’ Yet, every biometric check consists of a process with many intermediate steps, introducing contingency and choice on many levels. In addition, there are underlying normative assumptions regarding human bodies that affect the functioning of biometric systems in highly problematic ways. In recent social science studies, the failures of biometric systems have been interpreted as gendered and racialized biases. A more nuanced understanding of how biometrics and bodily differences intersect draws attention to how bodily differences are produced, used, and problematized during the research and design phases of biometric systems, as well as in their use. In technical engineering research, issues of biometrics’ performance and human differences are already transformed into R&D challenges in variously more and less problematic ways. In daily practices of border control, system operators engage in workarounds to make the technology work well with a wide range of users. This shows that claims about ‘inherent whiteness’ of biometrics should be adjusted: relationships between biometric technologies, gender and ethnicity are emergent, multiple and complex. Moreover, from the viewpoint of theorizing gender and ethnicity, biometrics’ difficulties in correctly recognising pre-defined categories of gender or ethnicity may be less significant than its involvement in producing and enacting (new) gender and ethnic classifications and identities.

    Visual Communication and Social Change
    Witteveen, L.M. ; Lie, R. - \ 2019
    In: Handbook of Communication for Development and Social Change / Servaes, Jan, Springer - ISBN 9789811070358 - 24 p.
    Communication for development and social change - Communication for change - Strategic communication - Journalism and international communication - Health communication - Environmental communication - Social change activities - Knowledge management and development - Communication activities for development
    This chapter explores visual communication in the context of communication for social change with a major focus on the field of information and knowledge exchange in agriculture and rural development, formerly termed agricultural and rural extension. The specifics of visual communication, the appropriateness and effectiveness of visual communication in rural development, and social change processes are addressed proceeding from early understandings of visual communication to contemporary views. Reviewing work experiences, the authors searched for an analysis of the praxis and the very realities of visual communication and social change. The chapter concludes by arguing that, in contemporary visual communication, acknowledging diverse professionalisms, centralizing the importance of design thinking, and recognizing social imaginaries as options for visual communication in social dialogues are of crucial importance.
    Standards and Regulations for the Bio‐based Industry STAR4BBI
    Oever, M.J.A. van den; Vural Gürsel, Iris ; Bos, H.L. ; Dammer, Lara ; Babayan, Tatevik ; Ladu, Luana ; Clavell, Janire ; Vrins, Minique ; Berg, Janwillem van den - \ 2019
    Wageningen : Wageningen Food & Biobased Research - 52 p.
    This report describes possible solution directions to overcome market entry barriers due to regulation and standardisation that companies that are active in the bio‐based economy experience. The market entry barriers were investigated and described in the deliverable D2.1. Five main hurdles were described in D2.1:
    ‐ A number of issues around End‐of‐Life of bio‐based products
    ‐ Certification and standards
    ‐ Biofuel policy, and the fact that supporting policy for bio‐based products is missing
    ‐ Missing long term policy that helps to promote bio‐based products
    ‐ Communication and image.

    In order to define possible solution routes to the hurdles, for each hurdle the
    relevant stakeholders and their drivers towards the hurdle were investigated. Based on this investigation directions for solutions were defined and discussed with various stakeholders. Furthermore a workshop was held where the solutions were presented and discussed with a broad group of stakeholders.

    Solution directions defined for the first four identified hurdles are:
    ‐ End‐of‐Life issues: There is no general agreement on which EOL option is most preferable for a several bio‐based products. This relates to present regulations, recycling targets, and industrial operation practices and business models of waste processors. All parties involved would benefit from clear LCA data for EOL options for (groups of) products. This would allow governments, municipalities, consumers and waste processors to decide which product best goes where. Clear icons indicating the preferable EOL, EU wide can help to minimise products going into the “wrong” bin. And in particular cases it may be useful to indicate what is not the desired EOL route, e.g. for products which look like a particular
    material but in fact are not. Furthermore research on recycling of bio‐based plastics and composting of biodegradable plastics is proposed with both the bio‐based plastics suppliers and the waste processors being stakeholders in the project.
    ‐ Certification and standards: Several possible solutions are proposed to overcome the hurdle related to certification and standards. In principle, it is important to involve as many stakeholders as possible in the standardization process, in order to achieve a widely supported middle ground that corresponds as well as possible with everyday practice. Besides this, to give new materials the possibility to enter the market, standards should focus on the functioning of materials instead of the material itself. In the field of certificates, solutions lie in mutual compatibility, alignment and transparency in tests. However, aligning all involved parties can be (politically) challenging due to competition (between schemes). Moreover, amending standards is time consuming, but in the end
    these proposed solutions could open the door more easily to new bio‐based materials.
    ‐ Biofuel policy: The RED puts pressure on availability and price of biomass for bio‐based products. Different options are considered as potential solutions. One option is to reform the RED in order to integrate bio‐based chemicals and materials. Another option is without changing the RED to create a link of bio‐based materials to the RED through a “bio‐ticket” system. The third option considered is a new directive special for bio‐based materials. Furthermore a harmonized classification system of wastes and residues across EU is
    necessary, which needs to be implemented under the EU Waste Framework Directive (WFD). Where the use of feedstocks by the bio‐based products industry is possible, such Elimination of hurdles in standards and regulation uses must be incentivized. The same classification system that will be needed to be
    developed by the WFD will need to be adopted by the Biofuel policy for defining the feedstocks of “advanced biofuels”.
    ‐ Missing long term policy: In order to level the playing field between fossil‐based and biobased products two possible solutions are proposed. In the first place, the producer should be responsible for paying for the negative externalities of the production processes (e.g. possible damage to the environment) and not the whole society. Furthermore, sustainable
    certifications, currently often asked only for bio‐based products, should be requested for all products. The lack of clear, robust methodologies and criteria for assessing the sustainability of both bio‐based and fossil‐based products represents a major gap that is hampering the future development of the bio‐based industry. Development of the same sustainability criteria for all types of feedstock (bio‐based and fossil based) and all sectors (materials and fuels/energy) across the whole life‐cycle (material production, use and EOL)
    is proposed as a potential solution. And harmonization of LCA procedures is described to be important for this.

    During the investigation process it was found that the fifth hurdle, communication and image, was an integral part of the other four hurdles, it was therefore not investigated and presented separately, but integral with the other hurdles.

    The solution directions described in this report are focused specifically on the hurdles that were collected in D2.1 by interviewing a number of companies. During the investigation also more general aspects to stimulate the introduction of bio‐based products came up. An overview of these is presented in appendix A.

    The analysis laid down in this report has served as the basis for a deeper investigation and proposals to overcome specific market barriers, which are presented in D4.4, and proposals for supporting policy, presented in D3.3.
    European Agriculture and the Bioeconomy: A Historical Overview
    Purnhagen, Kai ; Matthews, Alan - \ 2019
    In: EU Bioeconomy Economics and Policies / Dries, L., Heijman, W., Jongeneel, R., Purnhagen, K., Wesseler, J., Cham : Palgrave (Palgrave Advances in Bioeconomy: Economics and Policies ) - ISBN 9783030286330 - p. 27 - 35.
    Articles 38–44 (Title III) of the Treaty on the Functioning of the European Union (TFEU) govern the European Union (EU)’s Common Agricultural Policy (CAP). Article 38 of the Treaty of Rome in 1957 laid down the establishment of a common market for agricultural products and Article 39 set up a CAP, which was subsequently largely decoupled from the rules of the other common markets. This chapter outlines the historical development of the CAP, the internal market for agriculture and its relationship to the bioeconomy. It illustrates the different steps taken in the agricultural market as well as the policy choices which lie behind it.
    Farmers' Knowledge and Practices of Potato Bacterial Wilt Management in Ethiopia
    Gobena, Shiferaw Tafesse ; Damtew, E. ; Mierlo, B.C. van; Lie, R. ; Lemaga, B. ; Sharma, Kalpana ; Leeuwis, C. ; Struik, P.C. - \ 2019
    - 1 p.
    Potato (Solanum tuberosum L.) is an increasingly important crop for food and nutrition security in Ethiopia. It is also a vital source of income and more than 3.7 million smallholder farmers are involved in potato production in the country. However, bacterial wilt is currently causing an overwhelming impact on the country's potato production systems, threatening food and nutrition security initiatives.
    A survey of 261 randomly selected smallholder farmers was carried out in three major potato growing districts in the central highlands of Ethiopia to examine farmers' knowledge and management practices of bacterial wilt, and to analyse the role of relevant knowledge in their practices. Considering their different characteristics, three groups of farmers were distinguished: producers of quality declared seed, producers of normal seed and producers of ware potatoes. The results of the study indicated that most farmers (72%) could recognise symptoms of the disease on infected potato plants. However, they had very limited knowledge of the disease including its causal agent, spreading mechanisms, and management methods. All of the farmers were unaware of the causal agent of the disease and there were significant incongruences between scientific explanations and farmers' understanding of the disease. The farmers provided different explanations and confused a causal agent of the disease with various factors, such as water shortage, insects, planting seed potato with high moisture content, and waterlogging. Further, the majority of the farmers (60%) did not know spreading mechanisms of the disease. There was also no statistically significant association between farmers' knowledge of the disease and the category of the farmers.
    Farmers' knowledge of recommended management methods for bacterial wilt was also limited. The study further showed that practices of farmers have striking implication for spreading of the disease instead of controlling it. Previous agricultural extension efforts did not have the desirable effect on farmers' knowledge and practices. Therefore, to bridge the gap between scientific knowledge and farmers' understanding and practices, farmers need to learn about the disease and how to manage it through appropriate learning approaches that foster innovations in their local context.
    Students’ experiences and perceptions of multicultural group work.
    Brinkman, Dine ; Popov, Vitaliy ; Fortuin, Karen ; Lie, Rico - \ 2019
    Toward sustainable management of phosphorus flows in a changing rural–urban environment: recent advances, challenges, and opportunities
    Wu, Jiechen ; Hartmann, Tobias Edward ; Chen, Wei Shan - \ 2019
    Current Opinion in Environmental Sustainability 40 (2019). - ISSN 1877-3435 - p. 81 - 87.

    While food is mainly produced in rural areas, the main drivers of consumption are urban environments. The increasing demand for food in cities leads to an accumulation of phosphorus (P) in urban environments, which affects P flows at multiple scales. This study reviewed recent advances, challenges, and opportunities for sustainable management of P flows in decoupled rural–urban environments. We discussed recent advances in Substance Flow Analysis (SFA) that enable the characterization of P flows in rural–urban environments and illustrate how urban consumption affects rural food production systems. Most challenges of SFA are associated with the (1) spatial decoupling of food production in rural areas and food consumption in urban systems at multiple scales, (2) temporal implications of substance flows on system analysis, and (3) increasing complexity of resource flows in rural–urban environments. We identified three main opportunities for future research on sustainable management of P flows. These opportunities lie in linking urban and rural SFA through multi-scale analysis, increasing both spatial and temporal resolution of P flows within various environments and identifying how linking urban to rural environments can reduce pressure on primary production systems. Also, we highlighted that methodological development on high-resolution SFA at multiple scales is needed to close P cycles between rural and urban systems and to allow the development of future, sustainable P management systems in the anthropogenic food production chain.

    Spontaneous fermentation of Munkoyo: a cereal-based beverage in Zambia
    Phiri, Sydney - \ 2019
    Wageningen University. Promotor(en): E.J. Smid; V. Fogliano, co-promotor(en): A.R. Linnemann; S.E. Schoustra. - Wageningen : Wageningen University - ISBN 9789463951296 - 112

    Fermentation is the oldest technology used in the production of many traditional cereal-based beverages across Africa. Munkoyo, a spontaneously fermented cereal-based beverage from Zambia and Democratic Republic of Congo is one of those beverages and the focal product studied in this thesis. It is consumed by large parts of the population, as an energy drink during travel or work on the field and is also consumed at social gatherings like wedding festivals and funerals. The processing of Munkoyo has to date not been standardized and greatly varies between different regions and processors. This may affect the quality and the safety of the beverage. Optimization of the processing methods and microbial composition of Munkoyo to attain good quality and a safe product can be a milestone leading to increased consumption of the beverage.

    Like all fermented foods, processing of Munkoyo relies on microbial activity transforming raw materials (cereals such as maize, millet and sorghum) into a processed product. The thesis focused on understanding the art of making Munkoyo by surveying different processors and linked this to the microbial community composition of fermenting microbes and their functionality in producing aroma compounds. Further, we investigated whether the source of the fermenting bacteria could lie in the Rhynchosia roots that are added during processing.

    Chapter 2 describes a survey using a semi structured questionnaire and focus group discussions in Lusaka, Chongwe, Chibombo and Mumbwa. The survey revealed that Munkoyo is consumed by the entire population, as an energy drink, during long hours of manual work, at social gatherings and is mainly processed at household level. Characterization of the bacterial communities of over 90 samples with 16S amplicon sequencing on DNA extracted from the entire bacterial community revealed six families of mainly lactic acid bacteria to dominate the bacterial communities. Chapter 3 reports that there are principally three processing methods of making Munkoyo with reference to three different agro-ecological zones of the country. Microbial community composition is affected by processing method. Chapter 4 describes a study where we used six single strain cultures of bacteria commonly found as members of the microbial communities in Munkoyo and combinations of them to determine the most influential bacteria or groups of bacteria in the production of aroma compounds. We found that spontaneously fermented Munkoyo and Munkoyo made with the combination of all six species of bacteria had a similar composition of aroma compounds compared to the regular product implying that a complete mixture of microbes is required to potentially be used as starter culture for Munkoyo production. Chapter 5 reports on a study addressing the question if the addition of Rhynchosia root during processing provides the source of lactic acid bacteria responsible for fermentation. The study showed that microbial communities present on the roots used to make Munkoyo are mainly non-lactic acid bacteria like Propionibacteriaceae. Lactic acid bacteria were present at relative abundances below ten percent. After fermentation, the resulting product was dominated by lactic acid bacteria (Lactobacillaceae, Enterobacteriaceae, Leuconostocaceae, Streptococcaceae), which is a normal microflora in most cereal-based beverages. This supports the idea that Rhynchosia root is a potential source of lactic acid bacteria in spontaneous fermentation of Munkoyo.

    The work presented in this thesis highlights that spontaneous fermentation of Munkoyo possesses the challenge of product inconsistence from different processing methods. Further, the consequences and risks associated with contamination by pathogenic bacteria remains to be explored. Optimizing the processing methods and standardizing the microbial composition by administering starter culture can ultimately enhance quality and safety of the product to formalize production, increase consumption and contribute to food security.

    Calcium Carbonate Packed Electrochemical Precipitation Column: New Concept of Phosphate Removal and Recovery
    Lei, Yang ; Narsing, Santosh ; Saakes, Michel ; Weijden, Renata D. Van Der; Buisman, Cees J.N. - \ 2019
    Environmental Science and Technology 53 (2019)18. - ISSN 0013-936X

    Phosphorus (P) is a vital micronutrient element for all life forms. Typically, P can be extracted from phosphate rock. Unfortunately, the phosphate rock is a nonrenewable resource with a limited reserve on the earth. High levels of P discharged to water bodies lead to eutrophication. Therefore, P needs to be removed and is preferably recovered as an additional P source. A possible way to achieve this goal is by electrochemically induced phosphate precipitation with coexisting calcium ions. Here, we report a new concept of phosphate removal and recovery, namely a CaCO3 packed electrochemical precipitation column, which achieved improved removal efficiency, shortened hydraulic retention time, and substantially enhanced stability, compared with our previous electrochemical system. The concept is based on the introduction of CaCO3 particles, which facilitates calcium phosphate precipitation by buffering the formed H+ at the anode, releases Ca2+, acts as seeds, and establishes a high pH environment in the bulk solution in addition to that in the vicinity of the cathode. It was found that the applied current, the CaCO3 particle size, and the feed rate affect the removal of phosphate. Under optimized conditions (particle size, <0.5 mm; feed rate, 0.4 L/d; current, 5 mA), in a continuous flow system, the CaCO3 packed electrochemical precipitation column achieved 90 ± 5% removal of phosphate in 40 days and >50% removal over 125 days with little maintenance. The specific energy consumptions of this system lie between 29 and 61 kWh/kg P. The experimental results demonstrate the promising potential of the CaCO3 packed electrochemical precipitation column for P removal and recovery from P-containing streams.

    Identifying social norms in physical aspects of food environments: A photo study
    Raghoebar, Sanne ; Rongen, Sofie van; Lie, Rico ; Vet, Emely de - \ 2019
    Appetite 143 (2019). - ISSN 0195-6663
    Eating behavior - Food environments - Photo documentation - Physical cues - Semiology - Social norms

    It is widely accepted that physical food environments can contribute to unhealthy eating, but less is known about how physical cues in these environments actually stimulate eating. Our study starts from the assumption that social norms are embedded in physical cues and aims to make an inventory of physical cues that communicate what is socially accepted as normal and/or appropriate to eat in a Dutch outside-the-home food context. In Study 1, we conducted a qualitative study in which photographs taken in self-service food environments were analyzed using strategies from photo documentation and semiology. Grounded theory was applied to identify a wide variety of specific physical cues that were ultimately grouped into 18 higher level categories of physical cues (e.g. consumption traces, product availability). Most cue categories were associated with either descriptive or injunctive social norms, but some were associated with both types. In Study 2, we aimed to quantitatively cross-validate the social norm interpretations among laypeople (N = 173) by focusing on two selected photographs. More than half of the physical cues that participants identified in these photographs as being influential had been identified in Study 1 as cues bearing a normative message. The results further indicated that other people's behavior is easier to recognize in physical food environments than signals about what ought to be done. Given the great variety of identified physical cues associated with social norms, we posit that social norms are widely embedded in food environments and might guide eating behavior. Further research should study the effects of these cues on behavior and test whether the underlying process can be attributed to social norm interpretations.

    Competition between Escherichia coli Populations with and without Plasmids Carrying a Gene Encoding Extended-Spectrum Beta-Lactamase in the Broiler Chicken Gut
    Fischer, Egil A.J. ; Dierikx, Cindy M. ; Essen-Zandbergen, Alieda van; Mevius, Dik ; Stegeman, Arjan ; Velkers, Francisca C. ; Klinkenberg, Don - \ 2019
    Applied and Environmental Microbiology 85 (2019)17. - ISSN 0099-2240
    antibiotic resistance - Bayesian model - challenge - conjugation - experiment - poultry

    Extended-spectrum-beta-lactamase (ESBL)/AmpC-producing Escherichia coli strains are widely found in E. coli isolates from broiler feces, largely due to the presence of the blaCTX-M-1 gene on IncI1 plasmids. Plasmid carriage is theorized to cause fitness loss and thus should decrease under conditions of reduced antibiotic use. However, in vitro studies showed plasmid carriage to increase in the absence of antimicrobials, due to plasmid conjugation. We investigated whether this translates to increased levels of plasmid in the gastrointestinal tracts of chickens, where conjugation rates may be different and subtle differences in growth rates may have a larger impact on colonization. Eight groups of five chickens were orally inoculated at 4 days of age with a 0.5-ml volume containing 106 CFU/ml E. coli cells, of which 0%, 0.1%, 10%, or 100% carried the IncI1 plasmid with the gene blaCTX-M-1 At 13 time points during 41 days, fecal samples were taken from each chicken. E. coli strains with and without plasmids were quantified. Trends in E. coli subpopulations were analyzed using generalized linear mixed models, and population dynamics were studied by fitting to a mechanistic model. Trends in E. coli subpopulations were different between groups rather than between individual chickens, suggesting substantial levels of E. coli exchange between chickens in a group. The IncI1 plasmid carrying blaCTX-M-1 was transferred with conjugation coefficients at levels higher than those observed in vitro Across groups, the plasmids disappeared or were established independently of the initial fraction of plasmid-carrying E. coli, but no major increase occurred as observed in vitro Differences in growth rates were observed, but competitive exclusion of plasmid-carrying variants was counteracted by conjugation.IMPORTANCE Bacteria that produce extended-spectrum beta-lactamases are resistant to an important class of antimicrobials in human and veterinary medicine. Reduction in antibiotic use is expected to decrease the prevalence of resistance. However, resistance genes often lie on plasmids which can be copied and transferred to other bacteria by conjugation, so in vitro resistance was observed to increase in the absence of antimicrobials. We sought to determine whether this also occurs in the chicken gut and if competitive exclusion by similar E. coli variants without the resistance occurred. We studied the excretion of E. coli carrying IncI1 plasmids with the blaCTX-M-1 resistance gene in small groups of broiler chickens, after inoculating the chickens with E. coli suspensions containing different fractions of plasmid-carrying cells. Our results showed little variation between chickens within groups but large differences between groups that were independent of the ratio of variants with and without the plasmid and with persistence or extinction of the plasmid. However, there was no major plasmid increase as observed in vitro We conclude that in vivo studies with sufficient independent replications are important for intervention studies on plasmid-mediated antimicrobial resistance.

    Fishing activity near Wintershall offshore pipelines
    Hintzen, Niels - \ 2019
    IJmuiden : Wageningen Marine Research (Wageningen Marine Research report C073/19) - 22
    On the North Sea bottom lie numerous pipelines to link oil- or gas offshore units, - platforms and processing stations on land. Although pipeline tubes are coated and covered with protective layers (Concrete Weight Coating), the pipelines risk being damaged through man-made threats like fishing activities with bottom trawls (trawling interference), anchoring and dropped objects. IRM Systems performs integrated risk assessments of pipelines for amongst others Wintershall. Spatial maps of fishing activity would contribute to this risk assessment. Therefore, WMR was tasked to quantify the amount of fishing activity in the vicinity of Wintershall pipelines. Fishing activity has been quantified at a spatial scale of approximate 2500 m2 blocks (50m by 50m) using fishing Vessel Monitoring System (VMS) data for 2016 and 2018. In total, for each year 69 shapefiles specifying the fishing intensity in a buffer area of 100m either side of the pipeline, were delivered. The overall total trawl fishing intensity in 2016 and 2018 along the pipeline trajectories ranges from 0 - 18.83 times per grid cell per year and is the result of combining all beam-trawl fleet activities, though split by large beam trawls and shrimp trawls. There is substantial difference in effort between 2016 and 2018 which varies up to 200% for some pipeline segments. Though, at the North Sea scale, fishing has been relatively stable over the past 10 years. Highest fishing intensities are recorded within the 12nm zone where the effort of the shrimp trawlers is most abundant and has increased almost 5-fold in some areas from 2010 and has not come to a halt yet. At the spatial scale relevant in this study, small spatial differences make for substantial differences though.
    Los Roques and Las Aves archipelagos, Venezuela: A marine ecological and conservation reconnaissance of two little-known southeastern Caribbean oceanic archipelagos
    Debrot, Adolphe O. ; Yranzo, Anaurora ; Arocha, Dulce - \ 2019
    Atoll Research Bulletin 2019 (2019)622. - ISSN 0077-5630 - p. 1 - 27.

    The Los Roques and Las Aves oceanic coral reef archipelagos of Venezuela lie in a biogeographically unique and biologically diverse area of the Caribbean and possess extensive coral reefs, seagrass beds, mangroves and shallow macroalgae meadows. The geographic location of these archipelagos safeguards them from most Western Atlantic hurricane damage as well as the most severe Caribbean coral bleaching episodes. While the Aves islands remain uninhabited and are an area of low accessibility, Los Roques has been a managed national park since 1972. We here present an updated synthesis of recent research for these archipelagos as an aid to scientists and conservationists interested in these island groups for which no recent ecological reviews are available. Los Roques has been much better documented than Las Aves and is the largest coral reef marine protected area of Venezuela. It has about 1,500 inhabitants living principally from tourism and fisheries. Studies show that Los Roques possesses fish populations that suffer comparatively less fishing pressure and may serve as a rare benchmark for pristine fish communities elsewhere in the Caribbean. It has also successfully maintained its importance to seabird colonies for the last five decades, notwithstanding serious marine park funding and staffing shortages. A new baseline biological inventory for Las Aves is particulary critical considering the fragmentary information available for this archipelago. The relatively intact and resilient oceanic coral reef systems of Los Roques and Las Aves are of regionally significant conservation value and deserve much more conservation and biodiversity attention than so far accorded.

    Meta-analysis of epigenome-wide association studies in neonates reveals widespread differential DNA methylation associated with birthweight
    Küpers, Leanne K. ; Monnereau, Claire ; Sharp, Gemma C. ; Yousefi, Paul ; Salas, Lucas A. ; Ghantous, Akram ; Page, Christian M. ; Reese, Sarah E. ; Wilcox, Allen J. ; Czamara, Darina ; Starling, Anne P. ; Novoloaca, Alexei ; Lent, Samantha ; Roy, Ritu ; Hoyo, Cathrine ; Breton, Carrie V. ; Allard, Catherine ; Just, Allan C. ; Bakulski, Kelly M. ; Holloway, John W. ; Everson, Todd M. ; Xu, Cheng Jian ; Huang, Rae Chi ; Plaat, Diana A. van der; Wielscher, Matthias ; Merid, Simon Kebede ; Ullemar, Vilhelmina ; Rezwan, Faisal I. ; Lahti, Jari ; Dongen, Jenny van; Langie, Sabine A.S. ; Richardson, Tom G. ; Magnus, Maria C. ; Nohr, Ellen A. ; Xu, Zongli ; Duijts, Liesbeth ; Zhao, Shanshan ; Zhang, Weiming ; Plusquin, Michelle ; DeMeo, Dawn L. ; Solomon, Olivia ; Heimovaara, Joosje H. ; Jima, Dereje D. ; Gao, Lu ; Bustamante, Mariona ; Perron, Patrice ; Wright, Robert O. ; Hertz-Picciotto, Irva ; Zhang, Hongmei ; Karagas, Margaret R. ; Gehring, Ulrike ; Marsit, Carmen J. ; Beilin, Lawrence J. ; Vonk, Judith M. ; Jarvelin, Marjo Riitta ; Bergström, Anna ; Örtqvist, Anne K. ; Ewart, Susan ; Villa, Pia M. ; Moore, Sophie E. ; Willemsen, Gonneke ; Standaert, Arnout R.L. ; Håberg, Siri E. ; Sørensen, Thorkild I.A. ; Taylor, Jack A. ; Räikkönen, Katri ; Yang, Ivana V. ; Kechris, Katerina ; Nawrot, Tim S. ; Silver, Matt J. ; Gong, Yun Yun ; Richiardi, Lorenzo ; Kogevinas, Manolis ; Litonjua, Augusto A. ; Eskenazi, Brenda ; Huen, Karen ; Mbarek, Hamdi ; Maguire, Rachel L. ; Dwyer, Terence ; Vrijheid, Martine ; Bouchard, Luigi ; Baccarelli, Andrea A. ; Croen, Lisa A. ; Karmaus, Wilfried ; Anderson, Denise ; Vries, Maaike de; Sebert, Sylvain ; Kere, Juha ; Karlsson, Robert ; Arshad, Syed Hasan ; Hämäläinen, Esa ; Routledge, Michael N. ; Boomsma, Dorret I. ; Feinberg, Andrew P. ; Newschaffer, Craig J. ; Govarts, Eva ; Moisse, Matthieu ; Fallin, M.D. ; Melén, Erik ; Prentice, Andrew M. ; Kajantie, Eero ; Almqvist, Catarina ; Oken, Emily ; Dabelea, Dana ; Boezen, H.M. ; Melton, Phillip E. ; Wright, Rosalind J. ; Koppelman, Gerard H. ; Trevisi, Letizia ; Hivert, Marie France ; Sunyer, Jordi ; Munthe-Kaas, Monica C. ; Murphy, Susan K. ; Corpeleijn, Eva ; Wiemels, Joseph ; Holland, Nina ; Herceg, Zdenko ; Binder, Elisabeth B. ; Davey Smith, George ; Jaddoe, Vincent W.V. ; Lie, Rolv T. ; Nystad, Wenche ; London, Stephanie J. ; Lawlor, Debbie A. ; Relton, Caroline L. ; Snieder, Harold ; Felix, Janine F. - \ 2019
    Nature Communications 10 (2019)1. - ISSN 2041-1723

    Birthweight is associated with health outcomes across the life course, DNA methylation may be an underlying mechanism. In this meta-analysis of epigenome-wide association studies of 8,825 neonates from 24 birth cohorts in the Pregnancy And Childhood Epigenetics Consortium, we find that DNA methylation in neonatal blood is associated with birthweight at 914 sites, with a difference in birthweight ranging from −183 to 178 grams per 10% increase in methylation (P Bonferroni < 1.06 x 10 −7 ). In additional analyses in 7,278 participants, <1.3% of birthweight-associated differential methylation is also observed in childhood and adolescence, but not adulthood. Birthweight-related CpGs overlap with some Bonferroni-significant CpGs that were previously reported to be related to maternal smoking (55/914, p = 6.12 x 10 −74 ) and BMI in pregnancy (3/914, p = 1.13x10 −3 ), but not with those related to folate levels in pregnancy. Whether the associations that we observe are causal or explained by confounding or fetal growth influencing DNA methylation (i.e. reverse causality) requires further research.

    ICTs for Learning in the Field of Rural Communication
    Lie, Rico ; Witteveen, Loes - \ 2019
    In: Handbook of Communication for Development and Social Change / Servaes, Jan, Springer Nature Singapore - ISBN 9789811070358 - 18 p.
    This contribution surveys learning approaches in the field of agricultural extension, agricultural advisory services, and rural communication and explores their relationships with Information and Communication Technologies (ICTs). It makes a distinction between theory-based approaches to learning and design-based approaches to learning. The reviewed theory-based approaches are social learning, experiential learning, collaborative learning, and transformative learning and the design-based approaches are visual learning, intercultural learning, and distance learning. The choice for surveying these specific approaches is based on the relevance that these approaches have for the field of agricultural extension, agricultural advisory services, and rural communication. It is concluded that learning itself is to be seen as social and behavioral change and that the group is much valued in existing learning processes. Furthermore, experiences and reflections are central elements in all reviewed learning processes, and the visual and the cultural play crucial roles.
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