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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    Beaver effects on macroinvertebrate assemblages in two streams with contrasting morphology
    Robinson, C.T. ; Schweizer, P. ; Larsen, A. ; Schubert, C.J. ; Siebers, A.R. - \ 2020
    Science of the Total Environment 722 (2020). - ISSN 0048-9697
    Aquatic invertebrates - Castor fiber - Ecohydrology - Geochemistry - Seasonality - Stable isotopes

    Beaver populations are increasing throughout Europe and especially in Switzerland. Beaver are major ecological engineers of fluvial systems, dramatically influencing river morphology, ecohydrology and, consequently, aquatic and terrestrial biota. This study compared macroinvertebrate assemblages and trophic structure at two beaver complexes with contrasting topography in Switzerland over an annual cycle. One complex (Marthalen) was in a low gradient open basin, whereas the other complex (Flaach) flowed through a higher gradient ravine-like basin. Both complexes were embedded in an overall agricultural landscape matrix. Water physico-chemistry differed between the two complexes with nitrogen, phosphorus, and DOC being higher at Marthalen than at Flaach. Both complexes showed strong seasonality in physico-chemistry, but retention of nutrients (N, P) was highest in summer and only at Marthalen. Both complexes also showed strong seasonality in macroinvertebrate assemblages, although assemblages differed substantially between complexes. At Marthalen, macroinvertebrate assemblages were predominantly lentic in character at ‘pool’ sites within the complex. At Flaach, lotic macroinvertebrate assemblages were common at most sites with some lentic taxa also being present. Dietary shifts based on carbon/nitrogen stable isotopes occurred in spring and summer among sites at both complexes (autochthonous resource use increasing over allochthonous resource use downstream), although being most pronounced at Marthalen. In contrast, similar resource use across sites occurred in winter within both complexes. Although beaver significantly influenced fluvial dynamics and macroinvertebrate assemblage structure at both complexes, this influence was most pronounced at Marthalen where beaver caused the system to become more wetland in character, e.g., via higher hydraulic residence time, than at Flaach. We conclude that topography can shape beaver effects on fluvial systems and resident biota.

    Overexpression of Ricinus communis L. malate synthase enhances seed tolerance to abiotic stress during germination
    Brito, Valdinei Carvalho ; Almeida, Catherine P. de; Barbosa, Rhaíssa R. ; Carosio, Maria G.A. ; Ferreira, Antônio G. ; Fernandez, Luzimar G. ; Castro, Renato D. de; Hilhorst, Henk ; Ligterink, Wilco ; Ribeiro, Paulo Roberto - \ 2020
    Industrial Crops and Products 145 (2020). - ISSN 0926-6690
    Abiotic stress - Castor bean - Functional characterization - Temperature-responsive genes

    Ricinus communis L. seeds can germinate at high temperatures, but further development of the seedlings is negatively affected. This mainly caused by impairment of energy-generating pathways when seeds are germinated at 35 °C. Ricinus communis malate synthase (RcMLS) is a key responsive gene in lipid mobilization and gluconeogenesis and as such might have a role in sustaining successful seed germination and seedling growth. Herein, we raised the question whether RcMLS might be involved in the biochemical and molecular mechanisms required for R. communis seed germination under unfavourable environmental conditions. For that, we used a robust approach that encompassed bioinformatics analysis, transgenic Arabidopsis thaliana (L.) Heynh seeds overexpressing RcMLS, along with phenotypical characterization of seed germination under abiotic stress. The phylogenetic tree revealed important evolutionary relationship amongst MLS sequences from R. communis and from other crop species/model plants. Overexpression of RcMLS enhanced A. thaliana seed germination under high temperature and salt stress. For example, wild-type A. thaliana Columbia seeds (Col-0) showed 37 % of maximum germination at 35 °C, whereas A. thaliana seeds overexpressing RcMLS showed up to 71%. When salt stress was applied (75 mM NaCl), maximum germination of Col-0 seeds reached 37%, whereas for A. thaliana seeds overexpressing RcMLS it reached up to 93%. Nuclear Magnetic Resonance (NMR) and Gas Chromatography coupled to Time-Of-Flight Mass Spectrometry (GC-TOF-MS) metabolomics analysis showed a robust metabolic signature of A. thaliana seeds overexpressing RcMLS in response to abiotic stress. They accumulated high levels of Met, Ile, fructose, glucose, and sucrose. Therefore, we suggested that overexpression of RcMLS has modulated the glyoxylate cycle and gluconeogenesis pathway in order to maintain cellular homeostasis under unfavorable environmental conditions. Our results provide important leads into the contribution of RcMLS to the underlying mechanism of R. communis seed germination under adverse environmental conditions. This might be helpful for breeding programs to develop more resistant R. communis cultivars which are more likely to sustain growth and high yield under the severe conditions found in arid and semi-arid areas worldwide.

    Some notes on beaver engineering
    Driessen, Clemens - \ 2019
    How to look at burrows and dams? Proposing an artistic field experiment to engage with the beaver question
    Driessen, Clemens - \ 2019
    Towards naturecultural heritage: appreciating the built environment of the beaver (Çastor fiber, et al.)
    Driessen, Clemens - \ 2019
    Elucidating transmission patterns of endemic Mycobacterium avium subsp. paratuberculosis using molecular epidemiology
    Mitchell, Rebecca M. ; Beaver, Annabelle ; Knupfer, Elena ; Pradhan, Abani K. ; Fyock, Terry ; Whitlock, Robert H. ; Schukken, Ynte H. - \ 2019
    Veterinary Sciences 6 (2019)1. - ISSN 2306-7381
    MLSSR typing - Mutation rate - Mycobacterial co-infections - Mycobacterium avium subsp. paratuberculosis (MAP) - Vertical transmission - Within-host evolution

    Mycobacterial diseases are persistent and characterized by lengthy latent periods. Thus, epidemiological models require careful delineation of transmission routes. Understanding transmission routes will improve the quality and success of control programs. We aimed to study the infection dynamics of Mycobacterium avium subsp. paratuberculosis (MAP), the causal agent of ruminant Johne's disease, and to distinguish within-host mutation from individual transmission events in a longitudinally MAP-defined dairy herd in upstate New York. To this end, semi-annual fecal samples were obtained from a single dairy herd over the course of seven years, in addition to tissue samples from a selection of culled animals. All samples were cultured for MAP, and multi-locus short-sequence repeat (MLSSR) typing was used to determine MAP SSR types. We concluded from these precise MAP infection data that, when the tissue burden remains low, the majority of MAP infections are not detectable by routine fecal culture but will be identified when tissue culture is performed after slaughter. Additionally, we determined that in this herd vertical infection played only a minor role in MAP transmission. By means of extensive and precise longitudinal data from a single dairy herd, we have come to new insights regarding MAP co-infections and within-host evolution.

    Zeven doden bij noodweer in Noord-Griekenland na extreem warme dagen
    Tsiringakis, Aristofanis - \ 2019

    Noodweer in Noord-Griekenland heeft woensdag zeven slachtoffers en minimaal 140 gewonden geëist. De storm stak op nadat het toeristische gebied de afgelopen dagen te kampen had gehad met temperaturen van boven de 40 graden. Het extreme weer valt nog niet meteen te verklaren door de klimaatverandering en voor toeristen is de bestemming nog niet gevaarlijk, zeggen experts.

    Modeling the effects of infection status and hygiene practices on Mycobacterium avium subspecies paratuberculosis contamination in bulk tank milk
    Rani, Surabhi ; Beaver, Annabelle ; Schukken, Ynte H. ; Pradhan, Abani K. - \ 2019
    Food Control 104 (2019). - ISSN 0956-7135 - p. 367 - 376.
    Bulk tank milk - Good hygiene practices - Johne's disease - Milk filters - Mycobacterium avium subsp. paratuberculosis - Washing efficiency

    Infectious diseases in dairy cattle are of significant concern to dairy industries because of their huge impact on animal health, milk production, and economics. Mycobacterium avium subsp. paratuberculosis (MAP)is a pathogenic bacterium that causes Johne's disease, one of the important endemic infectious diseases in dairy cattle. Contamination of bulk tank milk with MAP can occur through direct shedding into milk by infected cows (internal route), fecal contamination (fecal route), or introduction of soil and water containing MAP (environmental route). Humans can be exposed to MAP via raw milk consumption; additionally, there are reports of MAP survival in milk after pasteurization. The risk of human consumption is particularly important due to an association between MAP and human Crohn's disease. In the current study, we used a probabilistic modeling framework to predict the level of MAP contamination per liter in the bulk tank milk and weigh the relative importance of each contamination route. Our model focused on several different infection statuses and the contribution of each group to environmental and fecal contamination, in addition to internal route shedding. We assessed the influence of common hygiene practices, such as washing of udders before milking and the use of milk filters, on the concentration of MAP in bulk tank milk. We extracted parameters and their distributions from national surveys and thorough literature search. Our baseline model comprising all hygiene practices provided an average estimate of 0.76 log CFU/L for the final concentration of MAP in bulk tank milk, with a maximum of 6.70 log CFU/L and a minimum of 0.04 log CFU/L depending on herd size and the ratio of infection statuses. Results from sensitivity analyses indicated that the average fecal contamination showed the greatest impact on the final MAP concentration per liter in bulk tank milk, followed by herd size and washing efficiency. This study emphasized that good hygiene practices are crucial for maintaining the quality of raw milk in an endemically-infected dairy herd.

    The effect of oil type and solvent quality on the rheological behavior of zein stabilized oil-in-glycerol emulsion gels
    Zou, Yuan ; Thijssen, Pieter Paul ; Yang, Xiaoquan ; Scholten, Elke - \ 2019
    Food Hydrocolloids 91 (2019). - ISSN 0268-005X - p. 57 - 65.
    Emulsion gel - Hydrophobic interaction - Oil type - Rheological behavior - Solvent quality - Zein

    The aim of this study was to assess the effect of oil type and solvent quality on the structure formation and rheological properties of zein-stabilized oil-in-glycerol emulsion gels. To change the interactions within the system, four types of oil (medium chain triglyceride (MCT) oil, sunflower oil, extra virgin olive (EVO) oil, and castor oil) with different polarity were used, and the solvent quality was modified by temperature and water addition. In all cases, emulsion gels were obtained with G’ > G’’. At each protein concentration and oil content, the gel strength and crossover strain γco increased with an increase in oil polarity, indicating the formation of a stronger gel structure and higher stability against structure breakdown. These results are related to the fact that a higher oil polarity decreases the oil-protein hydrophobic interactions and thereby increasing the interactions between the proteins to form a strong network in the continuous phase. In addition, water addition to the continuous phase enhanced the gel strength and the resistance against structure breakdown for more apolar MCT oil, while the opposite results were observed for the more polar castor oil. The zein-based emulsion gels showed a thermo-responsive behavior, and different responses in structure collapse and rearrangements during heating and cooling were found for different oils. These simple approaches form an interesting route to tune the rheological properties of zein-based emulsion gels.

    Characterization of the superoxide dismutase gene family in seeds of two Ricinus communis L. genotypes submitted to germination under water restriction conditions
    Gomes Neto, V. ; Ribeiro, P.R. ; Del-Bem, L.E. ; Bernal, D.T. ; Cunha Lima, S.T. ; Ligterink, W. ; Fernandez, L.G. ; Castro, R.D. de - \ 2018
    Environmental and Experimental Botany 155 (2018). - ISSN 0098-8472 - p. 453 - 463.
    Castor bean - Germinability - Oilseeds - Oxidative stresses - Pre-germination treatments - Seed priming - Water restriction

    Abiotic stresses are the most important environmental factors that negatively affects crop production worldwide, whereas germination is the most critical phase in the plants life cycle. Water availability is essential for proper seed imbibition and vigorous germination and often scarce for Ricinus communis (castor bean) cultivated in semiarid regions of Brazil. Water restriction generally leads to the generation of reactive oxygen species (ROS) and one of the major families of enzymes that counteract ROS are superoxide dismutases (SODs). The objective of this study was to identify and characterize the SOD gene family of R. communis by phylogenetic, biochemical and gene expression analysis and link it to the effect of osmoconditioning on seed vigor. We characterized the effect of osmotic conditioning treatments of seeds of two contrasting R. communis cultivars, EBDA MPA34 and PARAGUAÇU, on germination performance. We also searched the R. communis genome for SOD genes and analyzed them phylogenetically and evaluated their activity and expression in embryos of seeds imbibed under different PEG concentrations (water restriction stress). We could show that some of these treatments improved germinability and vigor of seeds and seedlings in a cultivar-dependent manner. Additionally, R. communis seeds turned out to be very sensitive to the inhibition of germination by osmotic stress even at relative low concentrations. Eight SOD genes were found in the R. communis genome and classified based on phylogenetic analysis, protein domains and prediction of subcellular localization. SOD gene expression was mostly induced during seed imbibition, although their expression was generally inhibited in osmotic potentials below −0.6 MPa and showed partly different gene expression profiles between contrasting cultivars. Cv. PARAGUAÇU showed increased seed vigor after osmoconditioning as compared to cv. EBDA MPA34 which could be related to higher responses of some cv. PARAGUAÇU SOD genes to stress. Our results indicate that SOD genes might be of special interest for R. communis genetic engineering aimed at the increase of production in semiarid regions.

    Engineering storage capacity for volatile sesquiterpenes in Nicotiana benthamiana leaves
    Delatte, Thierry L. ; Scaiola, Giulia ; Molenaar, Jamil ; Sousa Farias, Katyuce de; Alves Gomes Albertti, Leticia ; Busscher, Jacqueline ; Verstappen, Francel ; Carollo, Carlos ; Bouwmeester, Harro ; Beekwilder, Jules - \ 2018
    Plant Biotechnology Journal 16 (2018)12. - ISSN 1467-7644 - p. 1997 - 2006.
    Nicotiana benthamiana - Lipid bodies - Secondary metabolites - Sesquiterpene - Storage - Triacylglycerol

    Plants store volatile compounds in specialized organs. The properties of these storage organs prevent precarious evaporation and protect neighbouring tissues from cytotoxicity. Metabolic engineering of plants is often carried out in tissues such as leaf mesophyll cells, which are abundant and easily accessible by engineering tools. However, these tissues are not suitable for the storage of volatile and hydrophobic compound such as sesquiterpenes and engineered volatiles are often lost into the headspace. In this study, we show that the seeds of Arabidopsis thaliana, which naturally contain lipid bodies, accumulate sesquiterpenes upon engineered expression. Subsequently, storage of volatile sesquiterpenes was achieved in Nicotiana benthamiana leaf tissue, by introducing oleosin-coated lipid bodies through metabolic engineering. Hereto, different combinations of genes encoding diacylglycerol acyltransferases (DGATs), transcription factors (WRINKL1) and oleosins (OLE1), from the oil seed-producing species castor bean (Ricinus communis) and Arabidopsis, were assessed for their suitability to promote lipid body formation. Co-expression of α-bisabolol synthase with Arabidopsis DGAT1 and WRINKL1 and OLE1 from castor bean promoted storage of α-bisabolol in N. benthamiana mesophyll tissue more than 17-fold. A clear correlation was found between neutral lipids and storage of sesquiterpenes, using synthases for α-bisabolol, (E)-β-caryophyllene and α-barbatene. The co-localization of neutral lipids and α-bisabolol was shown using microscopy. This work demonstrates that lipid bodies can be used as intracellular storage compartment for hydrophobic sesquiterpenes, also in the vegetative parts of plants, creating the possibility to improve yields of metabolic engineering strategies in plants.

    Longitudinal relationship between fecal culture, fecal quantitative PCR, and milk ELISA in Mycobacterium avium ssp. paratuberculosis-infected cows from low-prevalence dairy herds
    Beaver, A. ; Sweeney, R.W. ; Hovingh, E. ; Wolfgang, D.R. ; Gröhn, Yrjö T. ; Schukken, Y.H. - \ 2017
    Journal of Dairy Science 100 (2017)9. - ISSN 0022-0302 - p. 7507 - 7521.
    Fecal culture - Fecal quantitative PCR - Johne's disease - Milk ELISA - Mycobacterium avium ssp. paratuberculosis
    Mycobacterium avium ssp. paratuberculosis (MAP), the causative agent of ruminant Johne's disease, presents a particular challenge with regard to infection mitigation on dairy farms. Diagnostic testing strategies to identify and quantify MAP and associated antibodies are imperfect, and certain facets of the relationship between diagnostic tests remain to be explored. Additional repeated-measures data from known infected animals are needed to complement the body of cross-sectional research on Johne's disease-testing methods. Statistical models that accurately account for multiple diagnostic results while adjusting for the effects of individual animals and herds over time can provide a more detailed understanding of the interplay between diagnostic outcomes. Further, test results may be considered as continuous wherever possible so as to avoid the information loss associated with dichotomization. To achieve a broader understanding of the relationship between diagnostic tests, we collected a large number of repeated fecal and milk samples from 14 infected cows, in addition to bulk milk samples, from 2 low-prevalence dairy herds in the northeast United States. Predominately through the use of mixed linear modeling, we identified strong associations between milk ELISA optical density, fecal quantitative PCR, and fecal culture in individual animals while concurrently adjusting for variables that could alter these relationships. Notably, we uncovered subtleties in the predictive abilities of fecal shedding level on milk ELISA results, with animals categorized as disease progressors reaching higher ELISA optical density levels. Moreover, we observed that spikes in fecal shedding could predict subsequent high ELISA values up to 2 mo later. We also investigated the presence of MAP in individual milk samples via PCR and noted an association between poor udder hygiene and MAP positivity in milk, suggesting some level of environmental contamination. The paucity of positive milk samples and the complete absence of detectable MAP in the bulk tank throughout the study period indicate that contamination of milk with MAP may not be of chief concern in low-prevalence herds. An enhanced understanding of the interrelationships between diagnostic tests can only benefit the development of testing strategies and objectives, which in turn may lessen MAP infection prevalence in dairy herds.
    The effect of oil type on network formation by protein aggregates into oleogels
    Vries, Auke de; Lopez Gomez, Yuly ; Linden, Erik van der; Scholten, Elke - \ 2017
    RSC Advances : An international journal to further the chemical sciences 7 (2017)19. - ISSN 2046-2069 - p. 11803 - 11812.

    The aim of this study was to assess the effect of oil type on the network formation of heat-set protein aggregates in liquid oil. The gelling properties of such aggregates to structure oil into so-called ‘oleogels’ are related to both the particle-particle and particle-solvent interactions. To change these interactions, four different oils (medium chain triglyceride oil, sunflower oil, extra virgin olive oil and castor oil) differing in polarity were used. The rheological properties of the protein aggregate oleogels were determined and compared to gels prepared with hydrophilic and hydrophobic colloidal silica particles at the same concentration. The results show that gel strength of the network formed by protein aggregates is affected by the polarity of the oil, resulting in weaker gels in more polar oils as a result of larger particle-solvent interactions. Similar results were obtained for hydrophilic silica particles. In the case of castor oil, the increased particle-solvent interactions though hydrogen bonds limited gel formation for all particle types. Large deformation rheology shows that protein oleogels exhibit a yielding behaviour under large deformation, but regenerate its elasticity quickly after deformation is reduced. The rapid recovery of the protein network and the fact that the interactions between the protein aggregates can be tuned by changing the characteristics of the oil, may be interesting features for various applications in foods.

    Negative priming of native soil organic carbon mineralization by oilseed biochars of contrasting quality
    Francischinelli Rittl, T. ; Novotny, E.H. ; Baliero, F.C. ; Hoffland, E. ; Alves, B.J.R. ; Kuijper, T.W.M. - \ 2015
    European Journal of Soil Science 66 (2015)4. - ISSN 1351-0754 - p. 714 - 721.
    Oilseed-derived biochar, a by-product of pyrolysis for biodiesel production, is richer in aliphatic compounds than the commonly studied wood-derived biochar, affecting both its mineralization in soil and its interaction with native soil organic carbon (nSOC). Here, we investigated the soil C sequestration potential of three different oilseed biochars derived from C3 plant material: soyabean, castor bean and jatropha cake. The chemical composition of these biochars was determined by elemental analysis (CHN) and 13C NMR spectroscopy. The cumulative CO2 efflux from 30-day laboratory incubations of biochar mixed with a sandy soil containing nSOC from C4 plants was measured as a proxy for mineralization rate. The relative contribution of each source to CO2 production was calculated based on the 13C-signatures of total CO2 efflux and the source materials (soil and biochars). Our results showed that: (i) castor bean biochar contained relatively large amounts of aliphatic compounds, resulting in a greater mineralization rate than soyabean and jatropha biochars; (ii) CO2 efflux from the soil-biochar mixtures originated mostly from the biochars, suggesting that these biochars contain rapidly decomposable compounds; and (iii) all three oilseed biochars decelerated nSOC mineralization. This negative priming effect appeared to be caused by different factors. We conclude that oilseed biochars have the potential to increase soil C stocks directly and increase soil C sequestration indirectly in the short term through negative priming of nSOC mineralization.
    Socioeconomic and environmental assessment of biodiesel crops on family farming systems in Brazil
    Belo Leitea, J.G. Dal; Barbosa Justino, F. ; Nunes Vieira da Silva, J.V. ; Florin, M.J. ; Ittersum, M.K. van - \ 2015
    Agricultural Systems 133 (2015). - ISSN 0308-521X - p. 22 - 34.
    nitrogen-use efficiency - land-use systems - integrated assessment - ecological intensification - cereal production - ammonium-sulfate - cropping systems - pest-management - yield - agriculture
    In Brazil, local agricultural research agendas are increasingly challenged by the search for sustainable biodiesel crop options for family farmers, especially under semi-arid conditions. The aim of this paper is to explore the suitability of different biodiesel crops (i.e. soybean, castor bean and sunflower) through a set of environmental and socioeconomic indicators in a semi-arid (Montes Claros) and a more humid (Chapada Gaúcha) municipality in the state of Minas Gerais, southeast Brazil. A technical coefficient generator (TechnoGIN) was used to assess current (maize, beans, soybean and grass seed) and alternative (castor bean and sunflower) crops grown with current and alternative production techniques. The quantification of the inputs and outputs was based on farm surveys, expert knowledge, literature and field experiments. Although castor bean and sunflower are economically competitive with maize in Montes Claros, feed and labour requirements may hinder farmers' adoption. In Chapada Gaúcha, the double cropping system soybean/sunflower presented small economic gains when compared to soybean; it also increased nitrogen losses and biocide residues. We conclude that the scope for alternative and sustainable biodiesel crops on family farms is limited. Their economic benefits are small or absent, while their introduction can lead to higher environmental impacts and there may be trade-offs with food and feed availability at the farm level.
    Integrated assessment of biodiesel policies aimed at family farms in Brazil
    Belo Leite, J.G. Dal; Nunes Vieira da Silva, J.V. ; Ittersum, M.K. van - \ 2014
    Agricultural Systems 131 (2014). - ISSN 0308-521X - p. 64 - 76.
    land-use - food - systems - models - future - oil - sufficiency - technology - management - options
    With many of the poor people in Brazil living in rural areas, local governments have intensified their efforts to design and implement effective policies that boost rural development. In 2004, a national program for production and use of biodiesel was launched aiming at increasing income among less endowed family farmers across the country. With expectations building on further expansion of the mandatory blending of biodiesel with fossil diesel, national and local government bodies are challenged by the search for policies able to foster biodiesel crop production through the wider cultivation of crops that produce more oil than soybean (e.g. sunflower and castor bean) and by improving the participation of less endowed farmers, especially in semi-arid regions. Therefore, the objective of this study was to perform an ex-ante integrated assessment of the socioeconomic and environmental impacts of four biodiesel policy scenarios towards different farm types in a semi-arid and more humid region of southeast Brazil. The applied modelling framework was a combination of a technical coefficient generator (TechnoGIN) and a bio-economic farm model (FSSIM). We explored the impact of market-driven (bonus price policy), input provision (fertiliser and land preparation policy) and oil production (oil mill policy) policy scenarios on soybean farmers in Chapada Gaúcha and maize/beans farmers in Montes Claros. The impacts of the different policies on farm gross margins, oil crop production, labour requirements, nitrogen losses and biocide residues were assessed against the baseline scenario. Our results indicated that the scope for biodiesel crops on smallholder, non-soybean producers in Montes Claros is less evident than in Chapada Gaúcha, particularly among the less endowed farmers for whom the increase in farm gross margin in all scenarios is limited to only 6% while oil production was 140 kg per farm, which is very low compared to the 41% increase and more than 48,000 kg of oil of soybean producers. The most effective policy scenario was the provision of inputs such as fertiliser and land preparation. Because in Montes Claros farmers have limited access to fertiliser, machinery and biocides, strategies that enable farmers to increase their cropped area (i.e. land preparation policy more than doubled the crop area) and crop yield levels (i.e. fertiliser policy almost quadrupled crop yields) have highest potential to benefit these farming systems.
    The first wolf found in the Netherlands in 150 years was the victim of a wildlife crime
    Gravendeel, B. ; Groot, G.A. de; Kik, M. ; Beentjes, K. ; Bergman, H. ; Caniglia, R. ; Cremers, H. ; Fabbri, E. ; Groenenberg, D. ; Grone, A. ; Groot Bruinderink, G.W.T.A. ; Font, I. ; Hakhof, J. ; Harms, V. ; Jansman, H.A.H. ; Janssen, R. ; Lammertsma, D.R. ; Laros, I. ; Linnartz, L. ; Marel, D. van der; Mulder, J.L. ; Mije, S. van der; Nieman, A.M. ; Nowak, C. ; Randi, E. ; Rijks, M. ; Speksnijder, A. ; Vonhof, H.B. - \ 2013
    Lutra 56 (2013)2. - ISSN 0024-7634 - p. 93 - 109.
    wolven - fauna - migratie - diergedrag - dna - biochemie - menselijke invloed - centraal-europa - noordoostpolder - wolves - fauna - migration - animal behaviour - dna - biochemistry - human impact - central europe - noordoostpolder
    On July 4th 2013 a dead subadult female wolf-like canid was found by the roadside between Luttelgeest and Marknesse in the Noordoostpolder in the central part of the Netherlands. As the last observations of wild wolves in the Netherlands date back to 1869 the discovery of this animal generated a lot of media attention. European wolf populations have been expanding since the 1950s and the first packs recently established themselves in Germany in geographic proximity of the Dutch border, so natural re-appearance of the species in the Netherlands seemed likely. We investigated the taxonomy of the animal, its geographical origin, and its most recent history. Macroscopic and biochemical analyses of the dead animal convincingly showed that it was a purebred wolf, related to populations from eastern Europe. Bullet impacts and shattered fragments found in the chest and flank, and a discrepancy between the timing of the post mortem and rigor mortis intervals indicated that this wolf was shot prior to illegal transport to the Netherlands. The wolf fed on beaver in either the Carpathian mountains or the Eifel which is too far for the animal to have walked from by itself within the 24 hours needed to digest its last meal. These geographical areas are the only regions where haplotypes and 87Sr/86Sr isotopes retrieved from both the dead wolf and the beaver remains in its stomach co-occur. We therefore conclude that the first Dutch wolf found in the Netherlands in 150 years did not enter the Netherlands by itself but sadly proved to be the victim of wildlife crime. Keywords: Canis lupus, Europe, haplotypes, isotopes, microsatellites, wildlife forensics, wolf.
    Family farmers and biodiesel production: Systems thinking and multi-level decisions in Northern Minas Gerais, Brazil.
    Florin, M.J. ; Ven, G.W.J. van de; Ittersum, M.K. van - \ 2013
    Agricultural Systems 121 (2013). - ISSN 0308-521X - p. 81 - 95.
    resource management - bayesian networks - policy - sustainability - arrangements - food
    This study focuses on family farmer engagement in the Brazilian national programme for Production and use of Biodiesel (PNPB). The Brazilian government has been promoting the role of family farmers as producers of biomass for biodiesel since 2004; however, fewer than expected family farmers have decided to produce biomass for biodiesel. The North of Minas Gerais is one region where a biodiesel plant has been strategically located to source castor beans grown by family farmers. The target family farm type in this region specializes in beef and/or dairy production with low input pasture (approximately 30 ha per farm), maize intercropped with beans (approximately 1 ha per farm) and sugarcane (approximately 1 ha per farm). We selected this region for a case study to explore management decisions of farmers, industry and policy makers that influence family farmer engagement with biodiesel production through cultivation of castor beans. To evaluate outcomes for family farmers engaging with the PNPB, we focused on how cultivation of castor beans impacts family farmers in terms of income levels, income stability and levels of milk production. We used an application of systems thinking known as Bayesian network modelling (BNM). BNM was chosen for its suitability to integrate different types of knowledge and to include quantitative and qualitative variables. The study was built on a body of scientific literature explaining why family farmers have not been cultivating castor beans for biodiesel production and a body of experiential knowledge of local actors (farmers, extension officers, policy makers, biodiesel manufacturers and researchers in North of Minas Gerais). The complete BNM consisted of a ‘cause and effect’ diagram where the strengths of the causal relationships were quantified with elicited opinions from surveyed local actors. We used the complete BNM to explore scenarios that could improve outcomes for family farmers and consequently increase their level of engagement. For example, we addressed subsidy structures of the PNPB, crop management, farm-level trade-offs and value-chain innovations. We demonstrate that decisions to support family farmer engagement with biodiesel are not singular. Engagement by family farmers requires simultaneously: improvements in technical crop management, reductions in farm-level cash constraints and innovations in the production chain such that engagement of family farmers goes beyond cultivation of one more low-value crop. Finally we discuss some methodological issues from this application of BNM to farming systems research.
    High rate heptanoate production from propionate and ethanol using chain elongation
    Grootscholten, T.I.M. ; Steinbusch, K.J.J. ; Hamelers, H.V.M. ; Buisman, C.J.N. - \ 2013
    Bioresource Technology 136 (2013). - ISSN 0960-8524 - p. 715 - 718.
    castor-oil - bacteria - acetate - acids
    Heptanoate (or enanthate), a saturated mono-carboxylate with seven carbon atoms, is a commercially produced biochemical building block with versatile applications. Currently, heptanoate is mainly derived from the oxidation of heptaldehyde, which can be obtained after pyrolysis of castor oil. The objective of this investigation was to achieve efficient high rate heptanoate production using a mixed culture chain elongation process based on propionate and ethanol. An efficient high rate heptanoate production using chain elongation could offer an alternative for heptanoate production from castor oil. The investigation was performed in an upflow anaerobic filter with a hydraulic retention time of 17 h. A heptanoate production rate of 4.5 g l-1 d-1 was achieved with a heptanoate concentration of 3.2 g l-1. These results show sufficient potential to consider this approach as an alternative for heptanoate production from castor oil. Future research should make heptanoate production from propionate and ethanol more cost-effective.
    The influence of the type of oil phase on the self-assembly process of ¿-oryzanol + ß-sitosterol tubules in organogel systems
    Sawalha, H.I.M. ; Margry, G. ; Adel, R. den; Venema, P. ; Bot, A. ; Flöter, E. ; Linden, E. van der - \ 2013
    European Journal of Lipid Science and Technology 115 (2013)3. - ISSN 1438-7697 - p. 295 - 300.
    edible oils - emulsions - mixtures
    Mixtures of ¿-oryzanol and ß-sitosterol were used to structure different oils (decane, limonene, sunflower oil, castor oil and eugenol). The ¿-oryzanol and ß-sitosterol mixtures self-assemble into double-walled hollow tubules (~10 nm in diameter) in the oil phase, which aggregate to form a network resulting in firm organogels. The self-assembly of the sterol molecules into tubules was studied using light scattering and rheology. By using different oils, the influence of the polarity of the oil on the self-assembly was studied. The effects of temperature and structurant concentration on the tubular formation process were determined and the thermodynamic theory of self-assembly was applied to calculate the change in Gibbs free energy ( DG0), enthalpy (DH0) and entropy ( DS0) resulting from the aggregation of the structurants was determined. The self-assembly was found to be enthalpy-driven as characterized by a negative DH0 and DS0. A decreasing polarity of the oil promotes the self-assembly leading to formation of tubules at higher temperatures and lower structurants concentrations.
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