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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    Evaluation of the impact of extrinsic rewards on user engagement in a health promotion context
    Nuijten, Raoul C.Y. ; Gorp, Pieter M.E. Van; Kaymak, Uzay ; Simons, Monique ; Kemperman, Astrid D.A.M. ; Berg, Pauline E.W. Van Den - \ 2019
    In: 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2019. - Berlin, Germany : Institute of Electrical and Electronics Engineers Inc. (Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS ) - ISBN 9781538613115 - p. 3600 - 3604.
    extrinsic rewards - health promotion - mHealth - social proof principle

    Despite the many mHealth solutions available, it remains unclear what their success factors are. Specifically, there has been controversy on the effectiveness of extrinsic rewards. This study evaluates two design elements of an mHealth solution -i.e., social proof and tangible rewards -and their impact on user engagement. During a four-week campaign, a sample of 143 university staff members engaged in a health promotion campaign. Participants were randomly distributed over one of three treatment groups. It was found that the introduction of a sufficiently meaningful, unexpected, and customized extrinsic reward can engage participants significantly more in a health promotion context.

    Using Unmanned Aerial Systems (UAS) and Object-Based Image Analysis (OBIA) for Measuring Plant-Soil Feedback Effects on Crop Productivity
    Nuijten, Rik J.G. ; Kooistra, Lammert ; Deyn, Gerlinde B. De - \ 2019
    Drones 3 (2019)3. - ISSN 2504-446X
    Unmanned aerial system (UAS) acquired high-resolution optical imagery and object-based image analysis (OBIA) techniques have the potential to provide spatial crop productivity information. In general, plant-soil feedback (PSF) field studies are time-consuming and laborious which constrain the scale at which these studies can be performed. Development of non-destructive methodologies is needed to enable research under actual field conditions and at realistic spatial and temporal scales. In this study, the influence of six winter cover crop (WCC) treatments (monocultures Raphanus sativus, Lolium perenne, Trifolium repens, Vicia sativa and two species mixtures) on the productivity of succeeding endive (Cichorium endivia) summer crop was investigated by estimating crop volume. A three-dimensional surface and terrain model were photogrammetrically reconstructed from UAS imagery, acquired on 1 July 2015 in Wageningen, the Netherlands. Multi-resolution image segmentation (MIRS) and template matching algorithms were used in an integrated workflow to detect individual crops (accuracy = 99.8%) and delineate C. endivia crop covered area (accuracy = 85.4%). Mean crop area (R = 0.61) and crop volume (R = 0.71) estimates had strong positive correlations with in situ measured dry biomass. Productivity differences resulting from the WCC treatments were greater for estimated crop volume in comparison to in situ biomass, the legacy of Raphanus was most beneficial for estimated crop volume. The perennial ryegrass L. perenne treatment resulted in a significantly lower production of C. endivia. The developed workflow has potential for PSF studies as well as precision farming due to its flexibility and scalability. Our findings provide insight into the potential of UAS for determining crop productivity on a large scale.
    Anthropology and the enigma of the state
    Stepputat, Finn ; Nuijten, M.C.M. - \ 2018
    In: Handbook of political Anthropology / Wydra, Harald, Thomassen, Bjørn, Edward Elgar Publishing Limited (Elgar Handbooks in Political Science ) - ISBN 9781743479009 - p. 127 - 144.
    This chapter provides an inventory of ‘the anthropology of the state’. It starts from the insight that the anthropology of the state drew considerably more on scholars of political science, political philosophy and sociology than on political anthropology. The ‘theoretical genealogies’ of the field challenged the taken-for-grantedness of the state as a ‘distinct, fixed and unitary entity’ operating outside and above society. The chapter concludes that the state as an idea of transcendental political authority and a centralizing organizational practice is not withering away, as observers in the 1990s suggested, but rather is transforming. The strongest contribution of political anthropology in grasping the manifold transformative processes is to combine rich ethnographic studies of this blurriness and the fragmentation of states with analyses of underlying rationales.
    Effects of protein supplementation on lean body mass, muscle strength, and physical performance in nonfrail community-dwelling older adults : a systematic review and meta-analysis
    Haaf, Dominique S.M. Ten; Nuijten, Malou A.H. ; Maessen, Martijn F.H. ; Horstman, Astrid M.H. ; Eijsvogels, Thijs M.H. ; Hopman, Maria T.E. - \ 2018
    American Journal of Clinical Nutrition 108 (2018)5. - ISSN 0002-9165 - p. 1043 - 1059.

    Background: Increasing protein intake has been suggested as an effective strategy to ameliorate age-related loss of muscle mass and strength. Current reviews assessing the effect of protein supplementation are strongly influenced by the inclusion of studies with frail older adults. Objectives: We assessed the effect of protein supplementation on lean body mass, muscle strength, and physical performance in exclusively nonfrail community-dwelling older adults. Moreover, we assessed the superior effects of protein supplementation during concomitant resistance exercise training on muscle characteristics. Design: A systematic literature search was conducted on PubMed, Embase, and Web of Science up to 15 May 2018. We included randomized controlled trials that assessed the effect of protein supplementation on lean body mass, muscle thigh cross-sectional area, muscle strength, gait speed, and chair-rise ability and performed random-effects meta-analyses. Results: Data from 36 studies with 1682 participants showed no significant effects of protein supplementation on changes in lean body mass [standardized mean difference (SMD): 0.11; 95% CI: -0.06, 0.28], handgrip strength (SMD: 0.58; 95% CI: -0.08, 1.24), lower extremity muscle strength (SMD: 0.03; 95% CI: -0.20, 0.27), gait speed (SMD: 0.41; 95% CI: -0.04, 0.85), or chair-rise ability (SMD: 0.10; 95%: CI -0.08, 0.28) compared with a control condition in nonfrail community-dwelling older adults. Moreover, no superior effects of protein supplementation were found during concomitant resistance exercise training on muscle characteristics. Conclusions: Protein supplementation in nonfrail community-dwelling older adults does not lead to increases in lean body mass, muscle cross-sectional area, muscle strength, or physical performance compared with control conditions; nor does it exert superior effects when added to resistance exercise training. Habitual protein intakes of most study participants were already sufficient, and protein interventions differed in terms of type of protein, amount, and timing. Future research should clarify what specific protein supplementation protocol is beneficial for nonfrail community-dwelling older adults with low habitual protein intake.

    Understanding obstacles and opportunities for successful market introduction of crop varieties with resistance against major diseases
    Nuijten, Edwin ; Wit, Jan de; Janmaat, Leen ; Schmitt, Annegret ; Tamm, Lucius ; Lammerts van Bueren, Edith T. - \ 2018
    Organic Agriculture 8 (2018)4. - ISSN 1879-4238 - p. 285 - 299.
    Agronomic and societal value - Brokerage - Comparative approach - Market introduction - Multilevel perspective - Resistance breeding

    Organic agriculture only allows a few ‘natural’ compounds for managing pests and diseases such as copper which is applied as fungicide in apple, grape, potato, and tomato production. But as a heavy metal, copper is under debate in the organic sector. One key strategy to replace copper use is the market introduction of resistant varieties. In this article, key obstacles and opportunities for the introduction of new apple and potato varieties are identified and described. A comparative analysis integrating agricultural, economic, cultural, and social perspectives is conducted based on literature review, information on internet, and interviews with key experts, mainly from the organic sector. As a framework for analysis, the concepts of brokerage and the multilevel perspective have been used. The following solution pathways are described: (a) make use of added value of varieties, (b) create demand (pull effects), (c) well-coordinated marketing concepts, (d) new marketing concepts such as the Flavour Group Concept, (e) gradual introduction through shorter chain (when limited funding), and (f) match varieties to food chain styles. Key lessons are the following: (i) there must be an urgent need that develops into a pull factor; (ii) for creating pull factors, it is important to involve others; (iii) a shared language and a common culture between involved stakeholders needs to be developed; (iv) without push factor, no new steps will be realised; (v) new concepts need to fit in existing chain structures; (vi) patience is often important, and (vii) some luck is often crucial.

    Towards resilience through systems-based plant breeding. A review
    Lammerts van Bueren, Edith T. ; Struik, Paul C. ; Eekeren, Nick van; Nuijten, Edwin - \ 2018
    Agronomy for Sustainable Development 38 (2018)5. - ISSN 1774-0746
    Agrobiodiversity - Breeding strategies - Common good - Ecological resilience - Entrepreneurial models - Resource use efficiency - Seed systems - Social justice - Societal resilience - Sustainability

    How the growing world population can feed itself is a crucial, multi-dimensional problem that goes beyond sustainable development. Crop production will be affected by many changes in its climatic, agronomic, economic, and societal contexts. Therefore, breeders are challenged to produce cultivars that strengthen both ecological and societal resilience by striving for six international sustainability targets: food security, safety and quality; food and seed sovereignty; social justice; agrobiodiversity; ecosystem services; and climate robustness. Against this background, we review the state of the art in plant breeding by distinguishing four paradigmatic orientations that currently co-exist: community-based breeding, ecosystem-based breeding, trait-based breeding, and corporate-based breeding, analyzing differences among these orientations. Our main findings are: (1) all four orientations have significant value but none alone will achieve all six sustainability targets; (2) therefore, an overarching approach is needed: “systems-based breeding,” an orientation with the potential to synergize the strengths of the ways of thinking in the current paradigmatic orientations; (3) achieving that requires specific knowledge development and integration, a multitude of suitable breeding strategies and tools, and entrepreneurship, but also a change in attitude based on corporate responsibility, circular economy and true-cost accounting, and fair and green policies. We conclude that systems-based breeding can create strong interactions between all system components. While seeds are part of the common good and the basis of agrobiodiversity, a diversity in breeding approaches, based on different entrepreneurial approaches, can also be considered part of the required agrobiodiversity. To enable systems-based breeding to play a major role in creating sustainable agriculture, a shared sense of urgency is needed to realize the required changes in breeding approaches, institutions, regulations and protocols. Based on this concept of systems-based breeding, there are opportunities for breeders to play an active role in the development of an ecologically and societally resilient, sustainable agriculture.

    Regimes de ordenação espacial no Brasil : A fusão de neoliberalismo, populismo de esquerda e visões modernistas na urbanização de favelas no Recife
    Nuijten, Monique ; Koster, Martijn ; Vries, Pieter de; Cabral, Augusto Antonio Campelo - \ 2018
    Caderno CRH 31 (2018)82. - ISSN 0103-4979 - p. 59 - 73.
    Favelas urbanization - Neoliberalism - Participation - Socialism - Urban space

    This article shows how regimes of spatial ordering are produced by the entangling of neoliberalism, leftist populism and modernist visions. It focuses on Prometrópole, a slum upgrading project in Recife. In this project, the neoliberal dimension manifests in the idea that the state, private companies and citizens together are responsible for (re)constructing urban space, and that beneficiaries are autonomous citizens, taking responsibility for their new living environment. The leftist political dimension is seen in participatory procedures to involve the residents in the project. The modernist aesthetics informs the project design with the requirement to use the new space according to the standards of “modern civilization”. As our research shows, such a regime of spatial ordering clashes with the livelihoods of the residents. Furthermore, the participatory procedures fail to grant them any real influence in creating their environment. Consequently, these residents drastically reconstruct their estate, reappropriating the urban space and contesting the regime imposed upon them.

    ‘When breaking you make your soul dance’ Utopian aspirations and subjective transformation in breakdance
    Bode Bakker, Maritza ; Nuijten, Monique - \ 2018
    Identities 25 (2018)2. - ISSN 1070-289X - p. 210 - 227.
    body - Breakdance - culture - resistance - utopia - youth
    This article is based on a study of the Naturalz crew, a ‘breaking’ or breakdancing group in Quito, Ecuador. Breaking is commonly analysed as a subculture of resistance. We analyse two–often neglected–dimensions of this resistance: the significance of utopian aspirations and the role of the body in subjective transformation. We argue that participants enact utopian values in breaking, for instance by affirming the value of street life and people from the streets. Furthermore, we see that breaking leads to subjective transformation among its young practitioners and that the body plays a central role in this change of subject position. It is interesting that girls use breaking to rebel against dominant images of ideal womanhood, resulting in changes in gendered subjectivity. Hence, from disempowered, marginalised young people, breakers turn into determined agents with physical strength and emotional resilience.
    Protein Intake and Distribution in Relation to Physical Functioning and Quality of Life in Community-Dwelling Elderly People: Acknowledging the Role of Physical Activity
    Haaf, Dominique ten; Dongen, E.J.I. van; Nuijten, M. ; Eijsvogels, Thijs ; Groot, C.P.G.M. de; Hopman, Maria - \ 2018
    Nutrients 10 (2018)4. - ISSN 2072-6643
    Increasing total protein intake and a spread protein intake distribution are potential strategies to attenuate sarcopenia related loss of physical function and quality of life. The aim of this cross-sectional study was to investigate whether protein intake and protein intake distribution are associated with muscle strength, physical function and quality of life in community-dwelling elderly people with a wide range of physical activity. Dietary and physical activity data were obtained from two studies (N = 140, age 81 ± 6, 64% male), with the following outcome measures: physical functioning (Short Physical Performance Battery (SPPB), comprising balance, gait speed and chair rise tests), handgrip strength and quality of life (EQ-5D-5L). Protein intake distribution was calculated for each participant as a coefficient of variance (CV = SD of grams of protein intake per main meal divided by the average total amount of proteins (grams) of the main meals). Based on the CV, participants were divided into tertiles and classified as spread, intermediate or pulse. The average total protein intake was 1.08 ± 0.29 g/kg/day. Total protein intake was not associated with outcome measures using multivariate regression analyses. Individuals with a spread protein diet during the main meals (CV < 0.43) had higher gait speed compared to those with an intermediate diet (CV 0.43–0.62) (β = −0.42, p = 0.035), whereas a spread and pulse protein diet were not associated with SPPB total score, chair rise, grip strength and Quality-Adjusted Life Year (QALY). The interaction of higher physical activity and higher total protein intake was significantly associated with higher quality of life (β = 0.71, p = 0.049). While this interaction was not associated with SPPB or grip strength, the association with quality of life emphasizes the need for a higher total protein intake together with an active lifestyle in the elderly.
    The antibody response in the bovine mammary gland is influenced by the adjuvant and the site of subcutaneous vaccination
    Boerhout, Eveline M. ; Koets, Ad P. ; Mols-Vorstermans, Tanja G.T. ; Nuijten, Piet J.M. ; Hoeijmakers, Mathieu J.H. ; Rutten, Victor P.M.G. ; Bijlsma, Jetta J.E. - \ 2018
    Veterinary Research 49 (2018)1. - ISSN 0928-4249
    Intramammary infections in cattle resulting in mastitis have detrimental effects on cows' well-being, lifespan and milk production. In the host defense against S. aureus mastitis antibodies are thought to play an important role. To explore potential ways to increase antibody titers in the bovine mammary gland the effects of various adjuvants on the magnitude, isotype, and neutralizing capacity of antibodies produced following subcutaneous vaccine administration at different immunization sites were analyzed. In this study, α-toxoid was used as a model antigen and formulated in three different alum-based adjuvants: Alum-Saponin, Alum-Oil, and Alum-Saponin-Oil. Vaccines were administered near the suspensory ligament of the udder or in the lateral triangular area of the neck. At both immunization sites, immunization with α-toxoid in Alum-Saponin-Oil resulted in higher specific antibody titers in milk and serum as compared with Alum-Oil and Alum-Saponin, without favoring an IgG1, IgG2, or IgA response. Furthermore, the neutralizing capacity of milk serum and serum following immunization near the udder and in the neck was higher when Alum-Saponin-Oil was used as adjuvant compared with Alum-Oil and Alum-Saponin. Prime immunizations near the udder effectively increased both antibody isotype titers and neutralization titers, while prime plus boost immunizations were required to induce similar effects following immunization in the neck. Results indicate that subcutaneous administration of an Alum-Saponin-Oil based vaccine near the udder could be further explored for the development of a one-shot vaccination strategy to efficiently increase intramammary antibody responses.
    Going for the dough : Engaging governmental funds in the Ciénega de Zacapu, Mexico
    Servin Juárez, Fidencio - \ 2018
    Wageningen University. Promotor(en): L.E. Visser, co-promotor(en): G.M. Verschoor. - Wageningen : Wageningen University - ISBN 9789463438292 - 167

    This study follows a planned development intervention involving greenhouse production systems for tomatoes. The intervention played out in Mexico, where the Planning Sub- Committee for Regional Development (SUPLADER) promoted a strategy for the "development" of the Zacapu region in Michoacán, from 2002 to 2005. The intervention is illustrated through a detailed, in-depth ethnographic case study of the way in which the Unión de Invernaderos Ruta de la Libertad (a USPR or Union of Rural Producers Association) sought to materialize a greenhouse project.

    Using an actor-oriented perspective (Long, 2001; Nuijten, 2001; Diego, 1997) and the concepts of actor’s agency, networks, associations, collectives and organizing processes, the study aims to understand the character of intervention, and shows how programs and development projects serve different purposes – purposes which symbiotically relate to the prevailing social conditions. As a general conclusion, I argue that what is called “the dough” (la lana) is what drives the dynamics of development intervention. While important, it is central to understand the different roles “the dough” plays in these intervention settings: for planners, it is the means to accomplish development, whereas for project beneficiaries it is a goal in itself.

    Chapter 1 elaborates on the general context of planned intervention in Michoacán’s Zacapu region, delineates the theoretical framework, presents the main research question (How do stakeholders organize themselves around the greenhouse project, and how do they redefine the view of planned development by the local government?) and elaborates on the methodology employed.

    Chapter 2 describes the organizing processes underlying implementation of the greenhouse project in the Zacapu - Ciénega region. It explains how, in order to acquire resources for the project, stakeholders organized into groups, forming Rural Production Associations (SPRs) and Unions of Rural Producers’ Associations (USPRs). As a result, a total of 28 SPRs were formed. For the most part, members of these SPRs had extensive, prior experience in organizing and participating in programs similar to those promoted by SUPLADER.

    Chapter 3 describes the practices of the eight groups (SPR) who got no resources from SUPLADER and seek to compensate for an initial investment from the Alliance for the Countryside (Alianza). To complete the project file, the groups were linked to government agencies, municipalities and communities as well as with external agents (firms) to use the register as a professional services provider (PSP) and enter the file to the Alianza program. In addition, power differences and conflict relationships were evident (Lukes, 1974); conditions that led to negotiation (Diego, 1997).

    Advisor firms were considered necessary for the negotiations since their capabilities were required and considered essential for the expected benefit of the Asociación, although they appeared to be a very powerful party. Despite the regulations established by the State to exercise governmental programs, the parties responsible for exercising them applied ambiguous criteria.

    Chapter 4 describes the development of an ideal configuration of greenhouses that included technological, social and cultural elements associated with safety practices, automation and demanding consumers located in an international market. This perception was far from the project conditions of greenhouses in La Ciénega; however, it did not prevent generating expectations among the SPRs. For these actors, the greenhouse became an alternative livelihood, income, and development opportunity.

    To interpret the processes described I used Latour’s (2008) notion of a sociology of associations; this allowed me to interpret how actor-networks were incorporated in the greenhouse project.

    Chapter 5 describes a breakaway attempt from the Asociación spearheaded by 17 SPRs that chose to build their greenhouses with an alternative hardware supplier (ACEA). To obtain the necessary funds new negotiations were started with a range of agencies. The move eventually strengthened the Asociación and its institutional embeddedness.

    In Chapter 6, the Asociación is shown to be a heterogeneous collective with different agendas. This resulted in several conflicts, some of them, involving the advisory offices that intended to take the resources (“the dough”) from the project. Nonetheless, a regional bank authorized a cash disbursement for the initial stage of the greenhouse project.

    Chapter 7 presents the final stage of SUPLADER Zacapu’s greenhouse project. After complex negotiations and conflicts within the Asociación, complementary credit was obtained for the construction of the greenhouse. However, during a municipal election campaign key figures in charge of implementation changed position; this led to a change in project conditions, and the Asociación had to face interventions from external actors. The negotiation game restarted and triggered a new set of strategies (amongst others to obtain money directly through the new SEPLADE delegate). Eventually, some of the Asociación’s funds were reappropriated and assigned to USPR Agrícola Tsakapu and different factions (vying for of resources) resulted fom this.

    Chapter 8 provides the discussion and conclusion to this thesis, with insights that build on Mosse’s (2005) argument that policies to promote development are associated to organizational demands and needs to maintain existing relationships (rather than promoting a previously defined policy). However, in the case of La Ciénega, the agents of change (including the Michoacán Congress) supported and pushed through planners’ development initiatives. In line with Ferguson (1994), I conclude that development must be understood in relation to the political-economic-cultural interests of those behind its design and implementation. Rather than linear, hegemonic and rigid, however, actors’ practices and strategies mould and twist planned development intervention to suit their needs and desires.

    Concepts and strategies of organic plant breeding in light of novel breeding techniques
    Nuijten, Edwin ; Messmer, Monika M. ; Lammerts van Bueren, Edith - \ 2017
    Sustainability 9 (2017)1. - ISSN 2071-1050
    Alternative techniques - Future perspectives - Guiding principles - Organic farming - Plant breeding

    In this paper, we describe the development of a set of guiding principles for the evaluation of breeding techniques by the organic sector over time. The worldwide standards of organic agriculture (OA) do not allow genetic engineering (GE) or any products derived from genetic engineering. The standards in OA are an expression of the underlying principles of health, ecology, fairness and care. The derived norms are process and not product oriented. As breeding is considered part of the process in agriculture, GE is not a neutral tool for the organic sector. The incompatibility between OA and GE is analyzed, including the "novel breeding techniques". Instead, alternative breeding approaches are pursued based on the norms and values of organic agriculture not only on the technical level but also on the social and organizational level by including other value chain players and consumers. The status and future perspectives of the alternative directions for organic breeding are described and discussed.

    Werken aan diversiteit in tarwe en groenten : voor meer variatie op het veld, in het winkelschap en op het bord
    Nuijten, Edwin ; Lammerts van Bueren, Edith - \ 2016
    Driebergen : Louis Bolk Instituut (Publicatie / Louis Bolk Instituut 2016-030 LbP) - 20
    kwekers - biologische landbouw - rassen (planten) - tarwe - zaden - plantenveredeling - groenten - genetische diversiteit - diversiteit - biologische plantenveredeling - growers - organic farming - varieties - wheat - seeds - plant breeding - vegetables - genetic diversity - diversity - organic plant breeding
    Van 2014 tot 2016 heeft het Louis Bolk Instituut onderzoek gedaan naar de mogelijkheden van een breder assortiment in gewassen voor de teler (op het veld) en voor de consument (op het bord). Aanleiding voor het onderzoek is dat het aantal rassen dat aangepast is aan biologische teeltomstandigheden (rassen die dus zonder gebruik van kunstmest en bestrijdingsmiddelen kunnen) beperkt is en blijft. Veel veredelingsbedrijven kunnen vanwege de ontwikkelingskosten geen aparte rassen ontwikkelen voor een kleine markt. Meestal worden rassen uit het bestaande (gangbare) assortiment geselecteerd voor biologische vermeerdering. Bovendien zijn biologische telers en handelaren meegegaan in de huidige eisen voor hoge opbrengst en uniforme eindproducten. Het aanbieden van zaadvaste rassen in plaats van bijvoorbeeld hybride rassen is daarmee commercieel niet meteen vanzelfsprekend. Divers en Dichtbij Van 2014 tot 2016 heeft het Louis Bolk Instituut onderzoek gedaan naar de mogelijkheden van een breder assortiment in gewassen voor de teler (op het veld) en voor de consument (op het bord). Dit onderzoek is samen met Estafette Odin BV en de biologische dynamische telers GAOS in Swifterbant, De Groenen Hof in Esbeek en de Maatschap Dames en Heren Vos in Kraggenburg uitgevoerd. Het doel van dit project Divers en Dichtbij was de diversiteit op het veld en op het bord te vergroten. Daarmee bedoelen we niet alleen meer verschillende rassen, maar vooral andere type rassen of populaties die zelf meer genetische variatie bezitten. Dat kan door te kiezen voor zaadvaste rassen bij groentegewassen en populaties bij granen. Tot nu toe is populatieveredeling alleen toegepast bij granen en nog niet of nauwelijks bij groentegewassen (zie voor definities Box 1 op pagina 7). Dit betekent ook een keuze voor andere manieren van veredelen en selecteren. Aanleiding voor het onderzoek is dat het aantal rassen dat aangepast is aan biologische teeltomstandigheden (rassen die dus zonder gebruik van kunstmest en bestrijdingsmiddelen kunnen) beperkt is en blijft. Veel veredelingsbedrijven kunnen vanwege de ontwikkelingskosten geen aparte rassen ontwikkelen voor een kleine markt. Meestal worden rassen uit het bestaande (gangbare) assortiment geselecteerd voor biologische vermeerdering. Bovendien zijn biologische telers en handelaren meegegaan in de huidige eisen voor hoge opbrengst en uniforme eindproducten. Het aanbieden van zaadvaste rassen in plaats van bijvoorbeeld hybride rassen is daarmee commercieel niet meteen vanzelfsprekend. En toch heeft ons brede speurwerk in dit project wel degelijk een aantal interessante zaadvaste rassen opgeleverd! Want gelukkig zijn er in Europa en Amerika diverse biologische veredelaars actief in het veredelen van zaadvaste rassen en populaties. De informatie in deze brochure is bedoeld voor telers en andere ketenpartijen om meer te leren over de mogelijkheden van zaadvaste rassen bij groenten en populaties bij tarwe.
    LukMF′ is the major secreted leukocidin of bovine Staphylococcus aureus and is produced in vivo during bovine mastitis
    Vrieling, Manouk ; Boerhout, Eveline M. ; Wigcheren, Glenn F. Van; Koymans, Kirsten J. ; Mols-Vorstermans, Tanja G. ; Haas, Carla J.C. de; Aerts, Piet C. ; Daemen, Ineke J.J.M. ; Kessel, Kok P.M. Van; Koets, Ad P. ; Rutten, Victor P.M.G. ; Nuijten, Piet J.M. ; Strijp, Jos A.G. van; Benedictus, Lindert - \ 2016
    Scientific Reports 6 (2016). - ISSN 2045-2322

    Staphylococcus aureus is a major human and animal pathogen and a common cause of mastitis in cattle. S. aureus secretes several leukocidins that target bovine neutrophils, crucial effector cells in the defence against bacterial pathogens. In this study, we investigated the role of staphylococcal leukocidins in the pathogenesis of bovine S. aureus disease. We show that LukAB, in contrast to the γ-hemolysins, LukED, and LukMF′, was unable to kill bovine neutrophils, and identified CXCR2 as a bovine receptor for HlgAB and LukED. Furthermore, we assessed functional leukocidin secretion by bovine mastitis isolates and observed that, although leukocidin production was strain dependent, LukMF′ was most abundantly secreted and the major toxin killing bovine neutrophils. To determine the role of LukMF′ in bovine mastitis, cattle were challenged with high (S1444) or intermediate (S1449, S1463) LukMF′-producing isolates. Only animals infected with S1444 developed severe clinical symptoms. Importantly, LukM was produced in vivo during the course of infection and levels in milk were associated with the severity of mastitis. Altogether, these findings underline the importance of LukMF′ as a virulence factor and support the development of therapeutic approaches targeting LukMF′ to control S. aureus mastitis in cattle.

    Coproducing urban space: Rethinking the formal/informal dichotomy
    Koster, Martijn ; Nuijten, Monique - \ 2016
    Singapore Journal of Tropical Geography 37 (2016)3. - ISSN 0129-7619 - p. 282 - 294.
    Providing an introduction to the special section ‘Close encounters: ethnographies of the coproduction of space by the urban poor’, this article sets out to argue that the image of ‘the informal’ as unruly, messy and dirty continues to inform urban planning around the world. As a reaction to this view, it contends that the informal and formal should be analysed as interconnected and that the informal sphere should be revalued. Urban development is studied as close encounters between established practices, with a locus and a history (tree-like), and newly emerging, unstable and untraceable practices (rhizomatic). Contrary to the tendency in urban planning to conflate the formal with the tree and the informal with the rhizome, we argue that from the perspective of marginal urbanites, formal planning tends to be very arbitrary and frightening (rhizomatic), whereas informal practices can be very predictable and stable (arboreal). The article analyses residents of marginalized urban areas as inventive navigators who explore the changing physical, spatial and sociopolitical environment, avoiding threats and looking for opportunities, grounded in their everyday practices and life histories. The article concludes that marginal urbanites should be acknowledged as coproducers of urban space and that the right to ‘coproduce’ the city lies at the heart of the call for the right to the city
    Reisolation of Staphylococcus aureus from bovine milk following experimental inoculation is influenced by fat percentage and specific immunoglobulin G1 titer in milk
    Boerhout, E.M. ; Koets, A.P. ; Vernooij, J.C.M. ; Mols-Vorstermans, T.G.T. ; Nuijten, P.J.M. ; Rutten, V.P.M.G. ; Bijlsma, J.J.E. ; Eisenberg, S.W.F. - \ 2016
    Journal of Dairy Science 99 (2016)6. - ISSN 0022-0302 - p. 4259 - 4269.
    Bovine mastitis - Milk fat percentage - Specific immunoglobulin G titer - Staphylococcus aureus

    The associations of management parameters, herd characteristics, and individual cow factors with bovine mastitis have been subject of many studies. The present study aimed to evaluate the association between milk composition parameters, including fat, protein, lactose, urea, and specific immunoglobulin levels, at the time of experimental bacterial inoculation of the mammary gland and subsequent shedding dynamics of Staphylococcus aureus. Sixty-eight cows were experimentally infected with S. aureus and closely monitored for 3 wk. Mixed model analyses were used to determine the influence of management and herd characteristics (farm and experimental group), individual cow factors (days in milk, milk yield, and quarter position), and a challenge-related parameter (inoculation dose) in combination with either the milk components fat, protein, lactose and urea, or the S. aureus-specific antibody isotype titers at the time of bacterial inoculation, on the number of S. aureus reisolated from milk after inoculation. A positive association was observed between the milk fat percentage and the number of S. aureus reisolated from quarter milk, and a negative relationship between the S. aureus-specific IgG1 titer in milk and the number of S. aureus. These findings should be considered in the development of a vaccine against S. aureus-induced bovine mastitis.

    The Use of Genomics in Conservation Management of the Endangered Visayan Warty Pig (Sus cebifrons)
    Nuijten, Rascha J.M. ; Bosse, Mirte ; Crooijmans, Richard P.M.A. ; Madsen, Ole ; Schaftenaar, Willem ; Ryder, Oliver A. ; Groenen, Martien A.M. ; Megens, Hendrik Jan - \ 2016
    International journal of genomcs 2016 (2016). - ISSN 2314-436X

    The list of threatened and endangered species is growing rapidly, due to various anthropogenic causes. Many endangered species are present in captivity and actively managed in breeding programs in which often little is known about the founder individuals. Recent developments in genetic research techniques have made it possible to sequence and study whole genomes. In this study we used the critically endangered Visayan warty pig (Sus cebifrons) as a case study to test the use of genomic information as a tool in conservation management. Two captive populations of S. cebifrons exist, which originated from two different Philippine islands. We found some evidence for a recent split between the two island populations; however all individuals that were sequenced show a similar demographic history. Evidence for both past and recent inbreeding indicated that the founders were at least to some extent related. Together with this, the low level of nucleotide diversity compared to other Sus species potentially poses a threat to the viability of the captive populations. In conclusion, genomic techniques answered some important questions about this critically endangered mammal and can be a valuable toolset to inform future conservation management in other species as well.

    Being Negro in Recife Brazil: A Political Aesthetics Approach
    Leerzem, L. van; Nuijten, M.C.M. ; Vries, P.A. de - \ 2016
    Ethnos : Journal of Anthropology 81 (2016)5. - ISSN 0014-1844 - p. 865 - 887.
    In this article, we explore the role of cultura negra and what it means to be negro for a particular segment of the population of Recife, Brazil. We zoom in on participants in Terça Negra (negro Tuesday), one of the foremost weekly events in the city. For these participants, self-identifying as negro refers not principally to skin colour but to an emancipatory project based on the consciência negra (negro consciousness), the awareness that poor people have in common a history of oppression and discrimination originating in times of slavery. Following the theoretical framing of Jacques Rancière, we argue that what is at stake in cultura negra and the assertion of negro identity is a political aesthetics formed through disagreement with the dominant order. We conclude by stressing the political significance of these zones of egalibertarian practices in the margins.
    Political activism and the PAH (Platform of Mortgage Victims) in Spain: the significance of Franz von Benda-Beckmann's work for the study of power, political agency and legal pluralism at the grassroots
    Nuijten, Monique - \ 2015
    Journal of Legal Pluralism and Unofficial Law 47 (2015)3. - ISSN 0732-9113 - p. 476 - 492.
    This article looks at the contribution of Franz von Benda-Beckmann to the analysis of
    political agency at the grassroots, especially the ways in which people at the margins
    and political activists contest existing structures of power. It examines in particular
    the relevance of von Benda-Beckmann’s approach for the analysis of the PAH
    (Platform of Mortgage Victims) in Spain, a social movement that stands up against the wave of house evictions as a result of the economic crisis and the collapse of the housing market.
    It is argued that people who have a contested relation with existing structures of
    power express normative values that differ from state rules. This makes legal
    anthropology in general, and von Benda-Beckmann’s approach of legal pluralism in particular, very relevant to this area of study. Von Benda-Beckmann’s thoughts about law and legal pluralism are discussed in relation to grassroots politics. The values of his ideas are highlighted as well as analytical points of departure from his views.
    Immunization routes in cattle impact the levels and neutralizing capacity of antibodies induced against S. aureus immune evasion proteins
    Boerhout, Eveline ; Vrieling, Manouk ; Benedictus, Lindert ; Daemen, Ineke ; Ravesloot, Lars ; Rutten, Victor ; Nuijten, Piet ; Strijp, Jos Van; Koets, Ad ; Eisenberg, Susanne - \ 2015
    Veterinary Research 46 (2015)1. - ISSN 0928-4249 - 9 p.

    Vaccines against S. aureus bovine mastitis are scarce and show limited protection only. All currently available vaccines are applied via the parenteral (usually intramuscular) route. It is unknown, however, whether this route is the most suitable to specifically increase intramammary immunity to combat S. aureus at the site of infection. Hence, in the present study, immunization via mucosal (intranasal; IN), intramuscular (triangle of the neck; IM), intramammary (IMM) and subcutaneous (suspensory ligament; SC) routes were analyzed for their effects on the quantity of the antibody responses in serum and milk as well as the neutralizing capacity of the antibodies within serum. The experimental vaccine comprised the recombinant S. aureus immune evasion proteins extracellular fibrinogen-binding protein (Efb) and the leukotoxin subunit LukM in an oil-in-water adjuvant combined with a hydrogel and alginate. The highest titer increases for both Efb and LukM specific IgG1 and IgG2 antibody levels in serum and milk were observed following SC/SC immunizations. Furthermore, the harmful effects of Efb and leukotoxin LukMF' on host-defense were neutralized by serum antibodies in a route-dependent manner. SC/SC immunization resulted in a significant increase in the neutralizing capacity of serum antibodies towards Efb and LukMF', shown by increased phagocytosis of S. aureus and increased viability of bovine leukocytes. Therefore, a SC immunization route should be considered when aiming to optimize humoral immunity against S. aureus mastitis in cattle.

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