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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    Amyloid aggregation of spin-labeled β-lactoglobulin. Part I : Influence of spin labeling on amyloid aggregation
    Lux, Jacqueline ; Heyn, Timon R. ; Kampen, Ingo ; Schwarz, Karin ; Keppler, Julia K. ; Steffen-Heins, Anja - \ 2021
    Food Hydrocolloids 112 (2021). - ISSN 0268-005X
    Amyloid aggregates - Fibrils - Site-directed spin labeling - β-Lactoglobulin

    Site-directed spin labeling (SDSL) of the natural food protein β-lactoglobulin (β-lg) was established with the aim of characterizing amyloid aggregation while explicitly avoiding the usual manipulation of primary protein structure. For its successful application, spin labels must not alter secondary protein structure or the formation of β-lg amyloid aggregates. The two spin labels—the MTSSL (flexible S–S binding) and Iodoacetamido-proxyl spin label (IPSL) (more rigid C–S binding)—were used for amyloid aggregation at pH 2 and pH 3.5. At pH 3.5, IPSL caused minor changes in the secondary protein structure, where it reduced intra- and intermolecular β-sheets as determined by ATR-FTIR. Analysis of the extent of amyloid aggregation using thioflavin T fluorescence indicated that the spin probes interfered with the binding of the fluorescent probes to the β-sheets. Non-amyloid and amyloid fractions were obtained from the amyloid aggregated system by ultrafiltration (300 kDa), which also proved to be equivalent and independent of the spin labeling process. Atomic force microscopy and size-exclusion chromatography results suggest the same building blocks and morphologies between unlabeled and spin-labeled proteins; therefore, substantial changes in the behavior of β-lg during amyloid aggregation can be excluded. Ultimately, 10–17% of the β-lg molecules were labeled so that the SDSL approach can be used to label the natural food protein at these low concentrations without affecting protein conformation or the formation of amyloid aggregates, which may subsequently provide deep insights into the aggregation mechanism of food proteins under processing conditions.

    Foams and air-water interfaces stabilised by mildly purified rapeseed proteins after defatting
    Yang, Jack ; Faber, Iris ; Berton-Carabin, Claire C. ; Nikiforidis, Constantinos V. ; Linden, Erik van der; Sagis, Leonard M.C. - \ 2021
    Food Hydrocolloids 112 (2021). - ISSN 0268-005X
    Atomic force microscopy - Foam - Lissajous plots - Oleosomes - Rapeseed proteins - Surface rheology

    Rapeseed protein isolate has promising functional properties (e.g. emulsifying and foaming), but is often extracted with intensive purification steps. This requires a considerable use of resources and damages protein functionality regarding, for instance, foam stabilization. We studied the interfacial and foaming properties of a mildly obtained rapeseed protein concentrate that contained oleosomes, and of its derived defatted rapeseed protein concentrate after solvent-based defatting. The air-water interfaces were deformed with large amplitude dilatational and shear deformations, which were analysed with Lissajous plots. At low bulk concentrations (0.01% w/w), the rapeseed protein-stabilised interfaces behaved as viscoelastic solids. The interfacial films became weaker and more stretchable at higher concentrations, suggesting that more non-protein components interfere with the intermolecular interactions between the adsorbed proteins at higher bulk concentrations. We confirmed the presence of such non-protein components at the interface by analysing Langmuir-Blodgett films with atomic force microscopy. The stability and air bubble size of foams prepared with either rapeseed protein concentrate or defatted rapeseed protein concentrate were similar. Mild purification of rapeseed resulted in a protein concentrate containing lipids in their native oleosome form, which have a minor destabilizing effect on foams. We conclude that mild purification is a suitable method to obtain sustainably produced protein concentrates with promising foaming properties.

    Towards recombinantly produced milk proteins : Physicochemical and emulsifying properties of engineered whey protein beta-lactoglobulin variants
    Keppler, Julia K. ; Heyse, Anja ; Scheidler, Eva ; Uttinger, Maximilian J. ; Fitzner, Laura ; Jandt, Uwe ; Heyn, Timon R. ; Lautenbach, Vanessa ; Loch, Joanna I. ; Lohr, Jonas ; Kieserling, Helena ; Günther, Gabriele ; Kempf, Elena ; Grosch, Jan Hendrik ; Lewiński, Krzysztof ; Jahn, Dieter ; Lübbert, Christian ; Peukert, Wolfgang ; Kulozik, Ulrich ; Drusch, Stephan ; Krull, Rainer ; Schwarz, Karin ; Biedendieck, Rebekka - \ 2021
    Food Hydrocolloids 110 (2021). - ISSN 0268-005X
    Two recombinant beta-lactoglobulin (BLG) B variants were produced in E. coli. Production/isolation resulted in native BLG without post-translational modifications. Properties of recombinant variants were compared to commercial BLG B and BLG AB. Minor differences in solubility and interface adsorption behavior were evident. Genetically engineered and natural BLGs show similar emulsifying properties.
    Mixing has limited impacts on the foliar nutrition of European beech and Scots pine trees across Europe
    Streel, Géraud de; Ammer, Christian ; Annighöfer, Peter ; Barbeito, Ignacio ; Bielak, Kamil ; Bravo-Oviedo, Andrés ; Brazaitis, Gediminas ; Buraczyk, Włodzimierz ; Collet, Catherine ; Hurt, Vaclav ; Kurylyak, Viktor ; Ouden, Jan den; Pach, Maciej ; Pretzsch, Hans ; Skrzyszewski, Jerzy ; Sramek, Vit ; Stankevičiūtė, Jolanta ; Strelcova, Katarina ; Svoboda, Miroslav ; Verheyen, Kris ; Zlatanov, Tzvetan ; Ponette, Quentin - \ 2020
    Forest Ecology and Management 479 (2020). - ISSN 0378-1127
    Complementarity - Fagus sylvatica L. - Foliar nutrition - Pinus sylvestris L. - Species mixture

    Tree species-mixing has been suggested as one option to counteract the adverse effects of global change on tree mineral nutrition, yet the effect of mixing on nutrient availability remains poorly documented. We therefore analyzed the current foliar nutrient (N, P, K, Ca, Mg) quantities and ilr balances (isometric log transformed ratios between elements or groups of elements) for 261 European beech and 248 Scots pine trees from 15 sites, each consisting of one beech-pine mixed stand and the respective monocultures, across a gradient of environmental conditions in Europe. We hypothesized an overall positive effect of mixing on tree foliar nutrient content, and that this mixing effect would be stronger on nutrient-poor sites. Using linear mixed models and multivariate linear regression models, we first tested for the effects of species (beech/pine) and composition (pure/mixed) across all sites; we then investigated whether the species-mixing effect was related to site fertility. The nutrient composition of beech leaves and pine needles differed significantly for all ilr balances. For both species, significant mixing effects were detected for some nutrients and ilr balances; those effects, however, could not be consistently related to contrasted nutrient composition between species. For most nutrients and ilr balances, the mixing effect was influenced by the site nutritional status, but the pattern differed from expectation: absence or minor differences between monocultures and mixtures at the lower end of the chemical fertility gradient, and maximum differences in rich soils. The contrasting foliar nutrient composition of pine and beech trees and the site nutrient status only partly explained the mixing effects on tree mineral nutrition. Our results claim for a better understanding of nutrient-related mechanisms associated with complementarity and points towards the need to further expand the existing frameworks to account for the multivariate nature of tree nutrition.

    Metrics to analyze and improve diets through food Systems in low and Middle Income Countries
    Melesse, Mequanint B. ; Berg, Marrit van den; Béné, Christophe ; Brauw, Alan de; Brouwer, Inge D. - \ 2020
    Food Security (2020). - ISSN 1876-4517
    Food systems - Indicators - Metrics - SDGs

    Taking a food systems approach is a promising strategy for improving diets. Implementing such an approach would require the use of a comprehensive set of metrics to characterize food systems, set meaningful goals, track food system performance, and evaluate the impacts of food system interventions. Food system metrics are also useful to structure debates and communicate to policy makers and the general public. This paper provides an updated analytical framework of food systems and uses this to identify systematically relevant metrics and indicators based on data availability in low and middle income countries. We conclude that public data are relatively well available for food system drivers and outcomes, but not for all of the food system activities. With only minor additional investments, existing surveys could be extended to cover a large part of the required additional data. For some indicators, however, targeted data collection efforts are needed. As the list of indicators partly overlaps with the indicators for the Sustainable Development Goals (SGDs), part of the collected data could serve not only to describe and monitor food systems, but also to track progress towards attaining the SDGs.

    Consumer preferences for farm-raised meat, lab-grown meat, and plant-based meat alternatives: Does information or brand matter?
    Loo, Ellen J. Van; Caputo, Vincenzina ; Lusk, Jayson L. - \ 2020
    Food Policy 95 (2020). - ISSN 0306-9192
    Cell-based - Consumer - Cultured - Demand - In-vitro - Lab-grown meat - Meat alternatives - Plant-based meat

    Despite rising interest in and sales of innovative non-animal-based protein sources, there remains a lack of information about consumer demand for these new foods and their ultimate market potential. This study reports the results of a nationwide survey of more than 1800 U.S. consumers who completed a choice experiment in which they selected among conventional beef and three alternative burger patties, (lab-grown, plant-based with pea protein, and plant-based with animal-like protein) at different prices. Respondents were randomly allocated to treatments that varied in the presence/absence of brands and information about the competing alternatives. Results from random parameter logit models indicate that, holding prices constant and conditional on choosing a food product, 72% chose farm-raised beef and 28% chose one of the alternatives: 16% plant-based (pea protein) meat alternative, 7% plant-based (animal-like protein) meat alternative, and 5% lab-grown meat. Adding brand names (Certified Angus Beef, Beyond Meat, Impossible Foods, and Memphis Meats) increased the share for choosing farm-raised beef to 80%. Environment and technology information had minor effects on conditional market shares but reduced the share of people not buying any options, indicating information pulled more people into the market. Even if plant- and lab-grown alternatives experienced significant (e.g., 50%) price reductions, farm-raised beef maintains the majority market share. Vegetarians, males, younger, and more highly educated individuals tend to have relatively stronger preferences for the plant- and lab-grown alternatives relative to farm-raised beef. More people opposed than supported taxing conventional beef for environmental and animal welfare objectives and more opposed than supported having plant- and lab-grown alternatives use the label ‘beef’

    Highly Stable Perovskite Supercrystals via Oil-in-Oil Templating
    Tang, Yingying ; Gomez, Leyre ; Lesage, Arnon ; Marino, Emanuele ; Kodger, Thomas E. ; Meijer, Janne Mieke ; Kolpakov, Paul ; Meng, Jie ; Zheng, Kaibo ; Gregorkiewicz, Tom ; Schall, Peter - \ 2020
    Nano Letters 20 (2020)8. - ISSN 1530-6984 - p. 5997 - 6004.
    assembly - emulsion-droplet templating - perovskite films - stability - supercrystals

    Inorganic perovskites display an enticing foreground for their wide range of optoelectronic applications. Recently, supercrystals (SCs) of inorganic perovskite nanocrystals (NCs) have been reported to possess highly ordered structure as well as novel collective optical properties, opening new opportunities for efficient films. Here, we report the large-scale assembly control of spherical, cubic, and hexagonal SCs of inorganic perovskite NCs through templating by oil-in-oil emulsions. We show that an interplay between the roundness of the cubic NCs and the tension of the confining droplet surface sets the superstructure morphology, and we exploit this interplay to design dense hyperlattices of SCs. The SC films show strongly enhanced stability for at least two months without obvious structural degradation and minor optical changes. Our results on the controlled large-scale assembly of perovskite NC superstructures provide new prospects for the bottom-up production of optoelectronic devices based on the microfluidic production of mesoscopic building blocks.

    Effects of on-farm and traditional hatching on welfare, health, and performance of broiler chickens
    Jong, Ingrid C. de; Hattum, Theo van; Riel, Johan W. van; Baere, Kris De; Kempen, Ine ; Cardinaels, Sofie ; Gunnink, Henk - \ 2020
    Poultry Science (2020). - ISSN 0032-5791
    broiler - health - on-farm hatching - production - welfare

    In on-farm hatching systems, eggs that have been incubated for 18 D are transported to the broiler farm. After hatching around day 21, the chicks have immediate access to feed and water. By contrast, traditionally hatched chicks are in early life exposed to dust and pathogens in the hatcher, handling procedures, and transport and remain without feed and water until they have arrived on the farm 1 to 3 D after hatching. We compared welfare and performance of on-farm hatched (OH) and traditionally hatched control (C) Ross 308 broiler chickens from day 0 to 40, housed under semicommercial conditions. The experiment included 3 production cycles in 4 rooms, with each room containing 1 OH and 1 C pen with 1,150 chickens in each pen. Per cycle, C and OH chicks were from the same batch of eggs of 1 parent stock flock. Day-old chick quality was worse for OH than C chickens (hock and navel score; P < 0.05). On-farm hatched chickens were heavier than C chickens until day 21 of age (P < 0.05). Total mortality was significantly lower in OH compared with C pens (P < 0.05). A tendency for lower footpad dermatitis scores was found in OH pens compared with C pens (P < 0.10), probably because of the dryer litter in OH than C pens (P < 0.05). No differences between treatments were found in gait, hock burn, cleanliness, and injury scores, and no or only minor, short lasting differences were found in pathology and intestinal histology. In conclusion, the present study showed that on-farm hatching may be beneficial for broiler welfare, as it reduced total mortality and resulted in dryer litter which is known to be beneficial for reducing footpad dermatitis.

    Effects of incubation temperature pattern on broiler performance
    Wijnen, H.J. ; Molenaar, R. ; Roovert-Reijrink, I.A.M. van; Pol, C.W. van der; Kemp, B. ; Brand, H. van den - \ 2020
    Poultry Science 99 (2020)8. - ISSN 0032-5791 - p. 3897 - 3907.
    broiler - chick quality - eggshell temperature - growth performance - incubation

    During incubation, development of embryos is affected by eggshell temperature (EST). A constant EST of 37.8°C has been considered so far to result in most optimal embryo development. However, it can be hypothesized that a higher EST in week 2 in combination with a lower EST in week 3 stimulates embryo development and subsequent grow-out performance. In this study, 468 eggs of a 44-week-old Ross 308 breeder flock were incubated at different incubation temperature patterns in a 2 × 2 factorial arrangement. In week 2, EST was either 37.8°C or 38.9°C, and in week 3, EST was either 37.8°C or 36.7°C. At hatch, chick quality was determined. Thereafter, 320 broilers were grown in 32 pens (8 replicates/treatment) for 6 wk. Weekly BW and ADFI were determined, and at day 40, slaughter yield from 128 broilers (4 per pen) was determined. Results showed that EST in week 2 did not interact with EST in week 3 for any variable. An EST of 38.9°C in week 2 resulted in a 1 mm longer chick length (P < 0.001) and 0.4 mmol/L lower blood glucose level (P = 0.04) at hatch than an EST of 37.8°C. Grow-out performance was not affected by EST in week 2 of incubation. An EST of 36.7°C in week 3 resulted in a 1 mm shorter chick length (P = 0.02), 1.0 mmol/L higher blood glucose level (P < 0.001), and higher relative heart (P = 0.01) and stomach weights (P = 0.03) at hatch than an EST of 37.8°C. Additionally, an EST of 36.7°C in week 3 resulted in lower BW, ADG, and ADFI on slaughter age (all P < 0.03) than an EST of 37.8°C. In conclusion, no interaction between EST in week 2 and 3 of incubation was found for any variable. A higher EST in week 2 had minor effects at hatching and during rearing, whereas a lower EST in week 3 seemed to result in better organ development, but resulted in lower grow-out performance.

    Pathogen effects on milk yield and composition in chronic subclinical mastitis in dairy cows
    Gonçalves, J.L. ; Kamphuis, C. ; Vernooij, H. ; Araújo, J.P. ; Grenfell, R.C. ; Juliano, L. ; Anderson, K.L. ; Hogeveen, H. ; Santos, M.V. dos - \ 2020
    The Veterinary Journal 262 (2020). - ISSN 1090-0233
    Chronic mastitis - MALDI-TOF MS - Milk component alteration - Milk loss - Repeated episode

    This study aimed to evaluate the effects of chronic subclinical mastitis (CSM) on milk production and component yields in dairy cows. A total of six herds located in the Midwest area of São Paulo State, Brazil were selected. Herds were visited once every 2 weeks to measure milk yield and to collect milk samples from lactating Holstein cows. Milk samples were collected at two stages (1 and 2), and each stage comprised three milk samplings. In stage 1, a total of 117 of 647 cows were diagnosed with CSM based on at least two of three repeated somatic cell counts (SCC) > 2000,000 cells/mL and positive bacterial milk culture results (BC). Cows with CSM were selected for the second stage. In stage 2, selected cows had quarter sampling aseptically collected for BC analyses prior to milking, and quarter milk yield was measured. Milk components (total protein, fat, lactose, and total solids) were measured using mid-infrared spectroscopy. Mammary quarters were considered healthy if all three repeated SCC results were ≤ 200,000 cells/mL and no bacterial growth was detected on BC. All quarters with positive bacterial growth were classified as having (non-chronic) subclinical mastitis when only one of three SCC results were > 200,000 cells/mL, and CSM when at least two of three SCC results were > 200,000 cells/mL. The effects of CSM by type of pathogen on milk and components yield were assessed using a linear mixed model. Mammary quarters with CSM caused by major pathogens had milk loss of 1.1 kg/quarter milking in comparison to healthy quarters. Milk losses were 0.8 and 1.3 kg/quarter milking when CSM was caused by Staphylococcus aureus or environmental streptococci, respectively. In addition, healthy quarters produced more milk components than quarters with CSM caused by major pathogens. Minor pathogens causing CSM (non-aureus staphylococci and Corynebacterium spp.) had no effect on milk yield. Quarters with CSM had lower milk and component yields when compared with healthy quarters. Milk losses varied according to the type of pathogen and were higher when associated with major pathogens such as S. aureus and environmental streptococci compared with healthy quarters.

    Congruence of Transcription Programs in Adult Stem Cell-Derived Jejunum Organoids and Original Tissue During Long-Term Culture
    Hee, Bart van der; Madsen, Ole ; Vervoort, Jacques ; Smidt, Hauke ; Wells, Jerry M. - \ 2020
    Frontiers in Cell and Developmental Biology 8 (2020). - ISSN 2296-634X
    gastrointestinal - intestinal organoids - IPEC-J2 - organoid stability - porcine organoids

    The emergence of intestinal organoids, as a stem cell-based self-renewable model system, has led to many studies on intestinal development and cell-cell signaling. However, potential issues regarding the phenotypic stability and reproducibility of the methodology during culture still needs to be addressed for different organoids. Here we investigated the transcriptomes of jejunum organoids derived from the same pig as well as batch-to-batch variation of organoids derived from different pigs over long-term passage. The set of genes expressed in organoids closely resembled that of the tissue of origin, including small intestine specific genes, for at least 17 passages. Minor differences in gene expression were observed between individual organoid cultures. In contrast, most small intestine-specific genes were not expressed in the jejunum cell line IPEC-J2, which also showed gene expression consistent with cancer phenotypes. We conclude that intestinal organoids provide a robust and stable model for translational research with clear advantages over transformed cells.

    The effect of microbial inoculant origin on the rhizosphere bacterial community composition and plant growth-promotion
    Gu, Yian ; Dong, Ke ; Geisen, Stefan ; Yang, Wei ; Yan, Yaner ; Gu, Dalu ; Liu, Naisen ; Borisjuk, Nikolai ; Luo, Yuming ; Friman, Ville Petri - \ 2020
    Plant and Soil 452 (2020). - ISSN 0032-079X - p. 105 - 117.
    Diversity - Microbial inoculation - Microbial transplants - Plant growth-promotion - Rhizosphere microbiota - Soil functioning

    Aims: Microbial inoculation has been proposed as a potential approach for rhizosphere engineering. However, it is still unclear to what extent successful plant growth-promoting effects are driven by the origin of the microbial inocula and which taxa are responsible for the plant-beneficial effects. Methods: We conducted a microbial transplant experiment by using different microbial inocula (and nutrient controls) isolated from forest, soybean and tomato field soils and determined their effects on tomato plant biomass and nutrient assimilation in sterilized tomato soil. Rhizosphere bacterial communities were compared at the end of the experiment and correlative and machine learning analyses used to identify potential keystone taxa associated with the plant growth-promotion. Results: Microbial inoculants had a clear positive effect on plant growth compared to control nutrient inoculants. Specifically, positive effects on the plant biomass were significantly associated with microbial inoculants from the forest and soybean field soils, while microbial inoculants from the forest and tomato field soils had clear positive effects on the plant nutrient assimilation. Soil nutrients alone had relatively minor effects on rhizosphere bacterial communities. However, the origin of microbial inoculants had clear effects on the structure of bacterial community structure with tomato and soybean inoculants having positive effects on the diversity and abundance of bacterial communities, respectively. Specifically, Streptomyces, Luteimonas and Enterobacter were identified as the potential keystone genera affecting plant growth. Conclusions: The origin of soil microbiome inoculant can predictably influence plant growth and nutrient assimilation and that these effects are associated with certain key bacterial genera.

    Removal of organic compounds from cooling tower blowdown by electrochemical oxidation : Role of electrodes and operational parameters
    Saha, Pradip ; Bruning, Harry ; Wagner, Thomas V. ; Rijnaarts, Huub H.M. - \ 2020
    Chemosphere 259 (2020). - ISSN 0045-6535
    Applied current density - Boron-doped diamond anode - Chlorinated by-products - Humic substances - Mixed-metal oxide anode

    The reuse of cooling tower blowdown (CTBD) in the cooling tower itself requires CTBD deionization and a pre-treatment before deionization to remove organic compounds (OCs) that induce membrane fouling. This study assesses the potential of electrochemical oxidation (EO) with a boron-doped diamond (BDD) and a Ti/RuO2 mixed-metal oxide (MMO) anode for CTBD pre-treatment. Also, the influence of the applied current density (j), initial pH, hydrodynamic conditions, and supporting electrolyte on the process performance was evaluated. Results show that COD and TOC removal were 85 and 51%, respectively, with the BDD-anode; however, they were 50 and 12% with MMO-anode at a j-value of 8.7 mA cm−2 and neutral pH. An increased j-value increased the COD and TOC removal; however, different pHs, hydrodynamic conditions, and the addition of supporting electrolytes had a minor impact on the removal with both anodes. Liquid chromatography-organic carbon detection analysis showed that the OC in CTBD mainly consisted of humic substances (HS). EO with the BDD-anode resulted in 35% HS mineralization, while the rest of the HS were partially oxidized into low molecular weight compounds and building blocks. However, HS mineralization was limited with the MMO-anode. The mineralization and oxidation were accompanied by the formation of organic and inorganic chlorinated species. These species increased the toxicity to Vibrio fischeri 20-fold compared to the initially low-toxic CTBD. Thus, EO with a BDD-anode is a promising pre-treatment technology for the removal of OCs before CTBD deionization, but measures to minimize the chlorinated species formation are required before its application.

    Neither poor nor cool : Practising food self-provisioning in allotment gardens in the Netherlands and Czechia
    Sovová, Lucie ; Veen, Esther J. - \ 2020
    Sustainability 12 (2020)12. - ISSN 2071-1050
    Allotment gardens - Alternative food networks - Coping strategy - Food self-provisioning - Practice theory - Quiet sustainability - Urban food

    While urban gardening and food provisioning have become well-established subjects of academic inquiry, these practices are given different meanings depending on where they are performed. In this paper, we scrutinise different framings used in the literature on food self-provisioning in Eastern and Western Europe. In the Western context, food self-provisioning is often mentioned alongside other alternative food networks and implicitly framed as an activist practice. In comparison, food self-provisioning in Central and Eastern Europe has until recently been portrayed as a coping strategy motivated by economic needs and underdeveloped markets. Our research used two case studies of allotment gardening from bothWestern and Eastern Europe to investigate the legitimacy of the diverse framings these practices have received in the literature. Drawing on social practice theory, we examined the meanings of food self-provisioning for allotment gardeners in Czechia and the Netherlands, as well as the material manifestations of this practice. We conclude that, despite minor differences, allotment gardeners in both countries are essentially 'doing the same thing.' We thus argue that assuming differences based on different contexts is too simplistic, as are the binary categories of 'activist alternative' versus 'economic need.'

    Wie doodt de agressieve Japanse duizendknoop, de ninja onder de invasieve exoten?
    Dijk, Chris van - \ 2020

    BNDe Japanse duizendknoop is de ninja onder de agressieve planten. Hij is nauwelijks te bestrijden. De wortel beschadigt gebouwen, taluds en rioleringen. Gilze en Rijen komt in december met een plan. Maar is dat wel op tijd?

    Purchasing and up-scaling of the privatized advisory services : An innovation perspective on privatized soil testing in Africa
    Malima, Gabriel ; Eshetie, Saba ; Rahaman, Abdulai ; Mrosso, Pastory ; Witteveen, Loes - \ 2020
    Community Development (2020). - ISSN 1557-5330
    Advisory services - innovation - purchase - soil test - technology

    As the trend of privatizing agricultural advisory services grows in developing countries, the need for the systematic thinking in innovation development is of interest for private companies that are trying to introduce various technologies in the agriculture sector. We explored the factors that affect the purchasing and upscaling of the privatized agricultural advisory services. We used a mobile soil testing service offered by a private company in Kenya as a case study. Additionally, we conducted minor explorations in Ethiopia, Ghana, and Tanzania. Our study found out that, while the service with its financial arrangement seems to be accepted by farmers, the social organization of system institutions is complex because not only technical factors but also social factors influenced adoption of the service. The study is an exemplifying case of the relevance of modeling innovations as complex configurations in a dynamic system of diverse actors in a community.

    Satellite evidence for changes in the NO2 weekly cycle over large cities
    Stavrakou, T. ; Müller, J.F. ; Bauwens, M. ; Boersma, K.F. ; Geffen, J. van - \ 2020
    Scientific Reports 10 (2020)1. - ISSN 2045-2322

    Anthropogenic activities, by far the largest source of NOx into the atmosphere, induce a weekly cycle of NO2 abundances in cities. Comprehensive analysis of the 2005–2017 OMI NO2 dataset reveals significant weekly cycles in 115 of the 274 cities considered. These results are corroborated by a full year of high-resolution TROPOMI NO2 observations. The OMI dataset permits us to identify trends in the weekly cycle resulting from NOx emissions changes. The data show a clear weakening of the weekly cycle over European and U.S. cities, an evolution attributed to the decline in anthropogenic emissions and the resulting growing importance of background NO2, whereas NO2 lifetime changes also play a minor role. In particular, the Sunday NO2 columns averaged over all U.S. cities are found to increase, relative to the weekly average, from 0.72 during 2005–2007 to 0.88 in 2015–2017. The opposite tendency is recorded in regions undergoing rapid emission growth. Multiyear simulations over the U.S. and the Middle East using the chemistry-transport model MAGRITTEv1.1 succeed in capturing the observed weekly cycles over the largest cities, as well as the observed long-term trends in the weekly cycle.

    Soils in lakes : the impact of inundation and storage on surface water quality
    Vink, Jos P.M. ; Comans, Rob N.J. ; Dijkstra, Joris J. ; Lamers, Leon P.M. - \ 2020
    Environmental Monitoring and Assessment 192 (2020)6. - ISSN 0167-6369
    Bioavailability - Biotic ligand models - Chemical extraction - Risk assessment - Sediment fluxes - Speciation - Suspended matter - Toxicity

    The large-scale storage and inundation of contaminated soils and sediments in deep waterlogged former sand pits or in lakes have become a fairly common practice in recent years. Decreasing water depth potentially promotes aquatic biodiversity, but it also poses a risk to water quality as was shown in a previous study on the impact on groundwater. To provide in the urgent need for practical and robust risk indicators for the storage of terrestrial soils in surface waters, the redistribution of metals and nutrients was studied in long-term mesocosm experiments. For a range of surface water turbidity (suspended matter concentrations ranging from 0 to 3000 mg/L), both chemical partitioning and toxicity of pollutants were tested for five distinctly different soils. Increasing turbidity in surface water showed only marginal response on concentrations of heavy metals, phosphorus (P) and nitrogen (N). Toxicity testing with bioluminescent bacteria, and biotic ligand modelling (BLM), indicated no or only minor risk of metals in the aerobic surface water during aerobic mixing under turbid conditions. Subsequent sedimentation of the suspended matter revealed the chemical speciation and transport of heavy metals and nutrients over the aerobic and anaerobic interface. Although negative fluxes occur for Cd and Cu, most soils show release of pollutants from sediment to surface waters. Large differences in fluxes occur for PO4, SO4, B, Cr, Fe, Li, Mn and Mo between soils. For an indicator of aerobic chemical availability, dilute nitric acid extraction (0.43 M HNO3; Aqua nitrosa) performed better than the conventional Aqua regia destruction. Both the equilibrium concentrations in surface waters, and fluxes from sediment, were adequately (r2 = 0.81) estimated by a 1 mM CaCl2 soil extraction procedure. This study has shown that the combination of 0.43 M HNO3 and 1 mM CaCl2 extraction procedures can be used to adequately estimate emissions from sediment to surface waters, and assess potential water quality changes, when former sand pits are being filled with soil materials.

    The influence of multi-stakeholder platforms on farmers' innovation and rural development in emerging economies : a systematic literature review
    Barzola Iza, Carlos L. ; Dentoni, Domenico ; Omta, Onno S.W.F. - \ 2020
    Journal of Agribusiness in Developing and Emerging Economies 10 (2020)1. - ISSN 2044-0839
    Farmers’ innovation - Impact pathways - Multi-stakeholder platforms - Rural development

    Purpose: Despite the increasing interest on multi-stakeholder platforms (MSPs) as novel organizational forms addressing grand challenges surrounding agri-food systems, the literature on how MSPs influence farmers' innovation remains scattered across sub-disciplines and geographies and, overall, of limited help for informing managerial and policy action and reflection. Design/methodology/approach: To address this gap, this systematic literature review (SRL) provides an overview on what MSPs are and how they influence farmers' innovation in emerging economies. Findings: The selected sample included n = 44 publications in 2004–2018, focussing for 70% on Africa, with minor shares in Latin America and Asia, and with a strong theoretical and methodological segmentation across five sub-disciplines (agribusiness management, agricultural economics, agricultural innovation systems, agricultural research for development and public policy and governance). Overall, this SRL leads to three findings. First, a key distinctive organizational feature of MSPs relative to other novel organizational forms in emerging economies entails the presence of a virtual and/or physical interface spanning across multiple heterogeneous stakeholders. Second, in relation to their impact pathways towards farmers' innovation, MSPs tend to achieve different intermediary outcomes and levels of innovation depending on their organizational goals and activities. Research limitations/implications: These findings also reveal four key limitations of the extant MSP literature – namely, disciplinary silos thinking, linear thinking, limited focus on the role of informal institutions and little emphasis on power dynamics – which could inform managers and policy makers on how MSPs could influence farmers; innovation. Originality/value: This study offers a SLR with the goal of providing practitioners and academics with first, a holistic view of the available research on the impact of MSPs on farmers innovation, and second, propose an impact pathway framework to understand how and under which circumstances MSPs support farmers' innovation given their functioning, structure and the governance mechanisms of MSPs.

    Size development of tomatoes growing in trusses: linking time of fruit set to diameter
    Tijskens, L.M.M. ; Mourik, S. van; Dieleman, J.A. ; Schouten, R.E. - \ 2020
    Journal of the Science of Food and Agriculture 100 (2020)10. - ISSN 0022-5142 - p. 4020 - 4028.
    Background: Size of fruit is an important issue in determining yield at harvest. Even under controlled conditions, variation between fruit and trusses can be considerable. As an easy to measure indication of size, the diameter of tomatoes growing in trusses was assessed in three experiments with different number of tomatoes per truss, as well as cultivars, and also by varying the level of ions in the recirculated drain water.
    Results: By applying the von Bertalanffy growth model, more than 99% of the variation present could be explained by the time of fruit set for all tomatoes growing anywhere in the trusses. A linear relationship between time of fruit set and the biological shift factor, an indication of developmental age, was observed. Integrating this linear relationship in the analysis of the diameter data removed one stochastic variable (biological shift factor), effectively halving the number of parameters to be estimated.
    Conclusion: The results of the present study indicate that the major part of the variation present in the diameter of tomatoes growing in trusses is the result of variation in the time of fruit set of individual fruits. The position within the greenhouse (i.e. local differences in assimilates supply) exerted only a minor effect on diameter development. Accordingly, the time of fruit set largely determines fruit size. Likely, growing conditions before fruit set are crucial for final fruit size. The time of fruit set of each tomato in the truss and the local growing conditions within the greenhouse that affect assimilate supply need to be assessed accurately for a reliable size prediction.
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