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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    Cryptosporidium concentrations in rivers worldwide
    Vermeulen, Lucie C. ; Hengel, Marijke van; Kroeze, Carolien ; Medema, Gertjan ; Spanier, J.E. ; Vliet, Michelle T.H. van; Hofstra, Nynke - \ 2019
    Water Research 149 (2019). - ISSN 0043-1354 - p. 202 - 214.
    Global - Model - Pathogens - Surface water - Transport - Water quality

    Cryptosporidium is a leading cause of diarrhoea and infant mortality worldwide. A better understanding of the sources, fate and transport of Cryptosporidium via rivers is important for effective management of waterborne transmission, especially in the developing world. We present GloWPa-Crypto C1, the first global, spatially explicit model that computes Cryptosporidium concentrations in rivers, implemented on a 0.5 × 0.5° grid and monthly time step. To this end, we first modelled Cryptosporidium inputs to rivers from human faeces and animal manure. Next, we use modelled hydrology from a grid-based macroscale hydrological model (the Variable Infiltration Capacity model). Oocyst transport through the river network is modelled using a routing model, accounting for temperature- and solar radiation-dependent decay and sedimentation along the way. Monthly average oocyst concentrations are predicted to range from 10−6 to 102 oocysts L−1 in most places. Critical regions (‘hotspots’) with high concentrations include densely populated areas in India, China, Pakistan and Bangladesh, Nigeria, Algeria and South Africa, Mexico, Venezuela and some coastal areas of Brazil, several countries in Western and Eastern Europe (incl. The UK, Belgium and Macedonia), and the Middle East. Point sources (human faeces) appears to be a more dominant source of pollution than diffuse sources (mainly animal manure) in most world regions. Validation shows that GloWPa-Crypto medians are mostly within the range of observed concentrations. The model generally produces concentrations that are 1.5–2 log10 higher than the observations. This is likely predominantly due to the absence of recovery efficiency of the observations, which are therefore likely too low. Goodness of fit statistics are reasonable. Sensitivity analysis showed that the model is most sensitive to changes in input oocyst loads. GloWPa-Crypto C1 paves the way for many new opportunities at the global scale, including scenario analysis to investigate the impact of global change and management options on oocysts concentrations in rivers, and risk analysis to investigate human health risk.

    JFR Special Issue on Agricultural Robotics
    Ball, David ; Upcroft, Ben ; Henten, Eldert van; Hengel, Anton van den; Tokekar, Pratap ; Das, Jnaneshwar - \ 2017
    Journal of Field Robotics 34 (2017)6. - ISSN 1556-4959 - p. 1037 - 1038.
    The Influence of Between-Farm Distance and Farm Size on the Spread of Classical Swine Fever during the 1997-1998 Epidemic in The Netherlands
    Boender, G.J. ; Hengel, R. van den; Roermund, H.J.W. van; Hagenaars, T.H.J. - \ 2014
    PLoS ONE 9 (2014)4. - ISSN 1932-6203 - 7 p.
    infectious-diseases - virus - transmission - strategies - model - risk
    As the size of livestock farms in The Netherlands is on the increase for economic reasons, an important question is how disease introduction risks and risks of onward transmission scale with farm size (i.e. with the number of animals on the farm). Here we use the epidemic data of the 1997–1998 epidemic of Classical Swine Fever (CSF) Virus in The Netherlands to address this question for CSF risks. This dataset is one of the most powerful ones statistically as in this epidemic a total of 428 pig farms where infected, with the majority of farm sizes ranging between 27 and 1750 pigs, including piglets. We have extended the earlier models for the transmission risk as a function of between-farm distance, by adding two factors. These factors describe the effect of farm size on the susceptibility of a ‘receiving’ farm and on the infectivity of a ‘sending’ farm (or ‘source’ farm), respectively. Using the best-fitting model, we show that the size of a farm has a significant influence on both farm-level susceptibility and infectivity for CSF. Although larger farms are both more susceptible to CSF and, when infected, more infectious to other farms than smaller farms, the increase is less than linear. The higher the farm size, the smaller the effect of increments of farm size on the susceptibility and infectivity of a farm. Because of changes in the Dutch pig farming characteristics, a straightforward extrapolation of the observed farm size dependencies from 1997/1998 to present times would not be justified. However, based on our results one may expect that also for the current pig farming characteristics in The Netherlands, farm susceptibility and infectivity depend non-linearly on farm size, with some saturation effect for relatively large farm sizes.
    The influence of herd size on the spread of classical swine fever during the 1997-1998 epidemic in The Netherlands
    Boender, G.J. ; Hengel, R. van den; Roermund, H.J.W. van; Hagenaars, T.H.J. - \ 2013
    Lelystad : Central Veterinary Institute of Wageningen UR (13/CVI0163 )
    As livestock farms in The Netherlands are nowadays being scaled up in size for economic reasons, the question becomes important how disease introduction risks and risks of onward transmission scale with farm size (i.e. with the number of pigs on the farm). Here we use the epidemic data of the 1997-1998 epidemic of Classical Swine Fever Virus (CSF) in The Netherlands to address this question for CSF risks. This dataset is one of the most powerful ones statistically as in this epidemic a total of 428 pig farms were infected (with the majority of farm sizes ranging between 27 and 1750 pigs). We have extended the earlier models for the transmission risk as a function of between-farm distance, by adding two size dependent factors: these factors describe the farm size dependence of, respectively, the susceptibility of an exposed farm and the infectivity of a source farm. Using the best-fitting model, we show that the size of a farm has a significant influence on both farm-level susceptibility and infectivity for CSF. Although larger farms are both more susceptible to CSF and, when infected, more infectious to other farms than smaller farms, the increase is less than linear. According to the best-fitting model, the higher the farm size, the smaller the effect on the susceptibility and infectivity of a farm of increments in farm size. We show that this implies, based on the pig farming characteristics of 1997-1998 in The Netherlands and assuming that the relative spatial distribution of farm locations does not change, a trend towards less but larger farms would produce a net decrease in between-farm transmission risks.
    Gedifferentieerd bestrijdingsbeleid bij een uitbraak van MKZ : aandacht voor niet-commercieel gehouden dieren
    Hagenaars, T.H.J. ; Hengel, R. van den; Asseldonk, Marcel van; Nodelijk, G. ; Bergevoet, R.H.M. - \ 2013
    Lelystad : Central Veterinary Institute (CVI rapport / Central Veterinary Institute, 13/CVI0183 ) - 17
    mond- en klauwzeer - mond- en klauwzeervirus - virusziekten - risico - diergezondheid - vaccinatie - verplichte vaccinatie - landbouwbeleid - dierenwelzijn - dierlijke productie - varkens - rundvee - schapen - foot and mouth disease - foot-and-mouth disease virus - viral diseases - risk - animal health - vaccination - mandatory vaccination - agricultural policy - animal welfare - animal production - pigs - cattle - sheep
    Wat is het extra verspreidingsrisico van geïnfecteerde bedrijven naar niet-geïnfecteerde bedrijven als niet-commercieel gehouden dieren worden gevrijwaard van preventieve ruiming in de eerste week van bestrijding van Mond en Klauwzeer virus (MKZ) in Nederland?
    Surveillance for an outbreak of African horse sickness in the Netherlands
    Hengel, Robert van den - \ 2012
    The influence of herd size on the spread of classical swine fever during the 1997-1998 epidemic in The Netherlands
    Hengel, Robert van den - \ 2012
    Workshop on a Risk Assessment of Crimean Congo Haemorrhagic Fever in West Europe, Lelystad, The Netherlands, 23-24 May 2012
    Hoek, M.R. ; Fischer, E.A.J. ; Hengel, R. van den; Backer, J.A. ; Koeijer, A.A. de - \ 2012
    Lelystad : Central Veterinary Institute (CVI rapport 12/CVI0361) - 37 p.
    Effects of feeding rapeseed oil, soybean oil or linseed oil on stearoyl-CoA desturase expression in the mammary gland of dairy cows
    Jacobs, A.A.A. ; Vuuren, A.M. van; Baal, J. van; Hengel, D. van de; Dijkstra, J. - \ 2009
    In: XIth International Symposium on Ruminant Physiology, Clermont-Ferrand, France, 6 - 9 September, 2009. - Wageningen : Wageningen Academic Publishers - p. 544 - 545.
    Extensive biohydrogenation of dietary fatty acids (FA) occurs in the rumen of dairy cattle, giving rise to a high proportion of saturated FA in milk fat. Saturated FA may contribute to increased risks of cardiovascular disease and the metabolic syndrome (Williams, 2000). Saturated FA, as well as several mono-unsaturated FA, can be desaturated by ¿9-desaturase, also known as stearoyl-CoA desaturase (SCD), present in the mammary gland of dairy cows. It is known that nutrition, especially polyunsaturated FA (PUFA), can affect the expression of SCD in rodents (Ntambi, 1999). Although various FA have been identified which can affect mammary SCD expression in dairy cattle, such knowledge is limited compared with rodents. Therefore, the objective of this study was to investigate the effect of dietary FA supplementation of C18:1 cis-9, C18:2 cis-9,12 or C18:3 cis-9,12,15, by feeding rapeseed oil, soybean oil or linseed oil respectively, or its mixture, on SCD expression in the mammary gland of dairy cows.
    A relationship between seed development, Arabinogalactan-proteins (AGPs) and the AGP mediated promotion of somatic embryogenesis
    Hengel, A.J. van; Kammen, A. van; Vries, S.C. de - \ 2002
    Physiologia Plantarum 114 (2002). - ISSN 0031-9317 - p. 637 - 644.
    Arabinogalactan-protein (AGP) epitopes are known to display developmentally regulated patterns of expression in several plant tissues. Therefore, AGPs have been suggested to play a role in plant development. Somatic embryogenesis is regulated by AGPs as well as by EP3 endochitinases. Using four different methods we have analysed the composition of AGPs in immature carrot seeds. The results obtained show that: (1) the native electrophoretic mobility of such AGPs changes during development; (2) AGP epitopes in immature seeds are developmentally regulated; (3) enzymatically released fragments of AGPs show that the composition of these molecules changes as a function of development; and (4) the biological activity of AGPs on the formation of somatic embryos changes depending on the age of the seeds. Our results suggest that degradation of maternally derived AGPs occurs after fertilization, while cellularization of the endosperm leads to synthesis of a new set of AGPs. The presence of an endochitinase cleavage site as well as the capacity to increase somatic embryogenesis only occurred in AGPs that were isolated from seeds in which the endosperm had been cellularized. Apparently, both EP3 endochitinases and somatic embryogenesis-promoting AGPs are developmentally regulated in immature carrot seeds.
    Bosdynamiek in bosreservaat Het Leesten
    Clerkx, A.P.P.M. ; Sanders, M.E. ; Bijlsma, R.J. - \ 2002
    Wageningen : Alterra (Alterra-rapport 556) - 55
    beschermde bossen - bosinventarisaties - bosecologie - vegetatie - nederland - gelderland - bosbouw - bosreservaat - Veluwe - reserved forests - forest inventories - forest ecology - vegetation - netherlands - gelderland
    Bosreservaat Het Leesten bestaat uit douglassparrenbos, Japanselariksbos en grovedennenbos. Hier zijn in 2000 voor de tweede keer de bosstructuur en vegetatie opgenomen. Het douglassparrenbos is erg stabiel; er hebben zich weinig verschuivingen voorgedaan. In het lariksbos vindt veel ingroei van douglasspar en fijnspar plaats. In het grovedennenbos verjongen berk en lijsterbes goed. Hier breidt douglasspar zich plaatselijk sterk uit. Hoewel het bosreservaat in de tweede helft van de negentiende eeuw is bebost, wijzen verschillende soorten erop dat het bosreservaat deel heeft uitgemaakt van een oudboslandschap met stabiele overgangen van bos naar heide. In het hele reservaat komen oude wintereikenstrubben, zowel individueel als in groepen. Verspreid voorkomende populaties van dalkruid, witte klaverzuring, bleeksporig bosviooltje, mannetjesereprijs, adelaarsvaren en hengel wijzen op de aanwezigheid van ousboscomplexen.
    Investment decision making in Dutch greenhouse horticulture
    Oude Lansink, A.G.J.M. ; Verstegen, J.A.A.M. ; Hengel, J.J. van den - \ 2001
    Netherlands Journal of Agricultural Science 49 (2001). - ISSN 0028-2928 - p. 357 - 368.
    Panel data from Dutch horticultural firms over the period 1986-1998 were used to analyse the effects of different factors on investment decisions. The factors analysed relate to the firm operator and his family, the firm structure and the economic environment. Results show that firm-operator and firm-family related characteristics play an important role in investment decision making. Moreover, variables that indicate the ability of the firm to attract debt capital and fulfil financial obligations, like firm size, solvency and net firm result, have a positive impact on investment decisions.
    N-acetylglucosamine and glucosamine-containing arabinogalactan proteins control somatic embryogenesis
    Hengel, A.J. van; Tadesse, Z. ; Immerzeel, P. ; Schols, H. ; Kammen, A. van; Vries, S.C. de - \ 2001
    Plant Physiology 125 (2001). - ISSN 0032-0889 - p. 1880 - 1890.
    In plants, complete embryos can develop not only from the zygote, but also from somatic cells in tissue culture. How somatic cells undergo the change in fate to become embryogenic is largely unknown. Proteins, secreted into the culture medium such as endochitinases and arabinogalactan proteins (AGPs) are required for somatic embryogenesis. Here we show that carrot (Daucus carota) AGPs can contain glucosamine and N-acetyl-D-glucosaminyl and are sensitive to endochitinase cleavage. To determine the relevance of this observation for embryogenesis, an assay was developed based on the enzymatic removal of the cell wall from cultured cells. The resulting protoplasts had a reduced capacity for somatic embryogenesis, which could be partially restored by adding endochitinases to the protoplasts. AGPs from culture medium or from immature seeds could fully restore or even increase embryogenesis. AGPs pretreated with chitinases were more active than untreated molecules and required an intact carbohydrate constituent for activity. AGPs were only capable of promoting embryogenesis from protoplasts in a short period preceding cell wall reformation. Apart from the increase in embryogenesis, AGPs can reinitiate cell division in a subpopulation of otherwise non-dividing protoplasts. These results show that chitinase-modified AGPs are extracellular matrix molecules able to control or maintain plant cell fate.
    Expression pattern of the Arabidopsis thaliana AtEP3/AtchitIV endocitinase gene
    Passarinho, P.A. ; Hengel, A.J. van; Fransz, P.F. ; Vries, S.C. de - \ 2001
    Planta 212 (2001). - ISSN 0032-0935 - p. 556 - 567.
    The carrot (Daucus carota L.) EP3 chitinase was shown to be essential for somatic embryo formation in a carrot mutant cell line. We identified the Arabidopsis thaliana (L.) Heynh. ortholog of the carrot EP3-3 chitinase gene, designated as AtEP3/AtchitIV and analyzed its expression in Arabidopsis by means of reverse transcription-polymerase chain reaction and promoter::#-glucuronidase and luciferase fusions. As in carrot, the gene is expressed during somatic embryogenesis in "nursing" cells surrounding the embryos but not in embryos themselves. In plants, gene expression is found in mature pollen and growing pollen tubes until they enter the receptive synergid, but not in endosperm and integuments as in carrot. Post-embryonically, expression is found in hydathodes, stipules, root epidermis and emerging root hairs, indicating that the Arabidopsis chitinase may have a function that is not restricted to embryogenesis.
    La Natura come casa mandata in rovina
    Hengel, A.H.E. van - \ 2000
    In: Domus Aeterna / Caus, W., Clevis, K., Leende : Damon - ISBN 9789055731275 - p. 48 - 51.
    De natuur als uitgewoond huis
    Hengel, A.H.E. van - \ 2000
    In: Domus Aeterna / Caus, W., Clevis, K., Leende : Damon - ISBN 9789055731275 - p. 10 - 13.
    Bestaat er interdisciplinaire wetenschap of onderzoek?
    Hengel, A.H.E. van - \ 2000
    In: Innovatie binnen Wageningen UR / Backus, G., - p. 13 - 25.
    Effect of AGPs and chitinases on somatic embryogenesis
    Kreuger, M. ; Hengel, A. van; Vries, S.C. de - \ 2000
    In: Cell and developmental biology of arabinogalactan proteins / Nothnagel, E.A., Bacic, A., Clarke, A.E., Kluwer Academic/Plenum Publishers - p. 54 - 61.
    Signal molecules in plant embryogenesis
    Hengel, A.J. van; Kammen, A. van; Vries, S.C. de - \ 1999
    In: Signal molecules in plant development / Schell, J., Walden, R., - p. 12 - 12.
    Sustainability and liveability : a deontological view on the Brundtland concept
    Hengel, A.H.E. van - \ 1999
    In: Preprints First European Congress on Agricultural and Food Ethics / V. Beekman, F. Brom (eds.). - Wageningen : [s.n.], 1999 - p. 41 - 44.
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