Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    '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.

    We have a manual that explains all the features 

    Records 1 - 20 / 5375

    • help
    • print

      Print search results

    • export
      A maximum of 250 titles can be exported. Please, refine your queryYou can also select and export up to 30 titles via your marked list.
    Check title to add to marked list
    Communicating the absence of evidence for microplastics risk: Balancing sensation and reflection
    Wardman, Toby ; Koelmans, A.A. ; Whyte, Jacqueline ; Pahl, Sabine - \ 2020
    Environment International (2020). - ISSN 0160-4120
    Communicating scientific evidence to decision makers and other stakeholders is an important task for scientists (SAPEA, 2019a, SAPEA, 2019b; Environmental and Health Risks of Microplastic Pollution, 2019). In this context, and specifically referring to recent evidence reviews on microplastics (SAPEA, 2019b, World Health Organization, 2019). Leslie and Depledge (2020) argue that both SAPEA (a consortium of European academies, part of the European Commission’s Scientific Advice Mechanism) and the UN’s World Health Organisation make the mistake of “assuming risk is absent in the absence of evidence”.
    In what follows, we reflect on their criticism and raise some broader issues about communicating science on an emerging issue. We make four points. Of the four, the first two reply directly to Leslie and Depledge. The third point briefly discusses the philosophical issue of whether, and to what extent, an absence of evidence constitutes evidence of absence, a topic whose origins can be traced back to the Enlightenment philosopher Locke (1689/1823). The fourth point provides a broader perspective on science communication for policy.
    We focus largely on Leslie and Depledge’s criticisms of the way the SAPEA report on microplastics (SAPEA, 2019b) was communicated, although we expect that similar responses might be made to their criticisms directed towards the WHO. Our effort is of course undertaken in Locke’s spirit of “the common offices of humanity and friendship in the diversity of opinions” (Locke, 1689/1823).
    Potential sources of bias in the climate sensitivities of fish otolith biochronologies
    Smoliński, Szymon ; Morrongiello, John ; Sleen, Peter Van Der; Black, Bryan A. ; Campana, Steven E. - \ 2020
    Canadian Journal of Fisheries and Aquatic Sciences 77 (2020)9. - ISSN 0706-652X - p. 1552 - 1563.

    Analysis of growth increments in the hard parts of animals (e.g., fish otoliths) can be used to assess how organisms respond to variability in environmental conditions. In this study, mixed-effects models were applied to otolith data simulated for two hypothetical fish populations with assumed biological parameters and known growth response to environmental variability. Our objective was to assess the sensitivity of environment-growth relationships derived from otolith biochronologies when challenged with a range of realistic ageing errors and sampling regimes. We found that the development of a robust biochronology and the precision of environmental effect estimates can be seriously hampered by insufficient sample size. Moreover, the introduction of even moderate ageing error into the data can cause substantial underestimation of environmental sources of growth variation. This underestimation diminished our capacity to correctly quantify the known environment-growth relationship and more generally will lead to overly conservative conclusions concerning the growth response to environmental change. Careful study design, reduction of ageing errors, and large sample sizes are critical prerequisites if robust inferences are to be made from biochronological data.

    Strategies of municipal land policies: housing development in Germany, Belgium, and Netherlands
    Shahab, Sina ; Hartmann, Thomas ; Jonkman, Arend - \ 2020
    European Planning Studies (2020). - ISSN 0965-4313
    Cultural Theory - housing - instruments - Land policy - strategy

    How do municipalities strategically use land policy to develop land for housing? The development of housing is a challenge for many European countries, though the scale and time of it differs. Issues are not always about the absolute number of houses that need to be supplied in a country. The distribution and quality of houses affect the demand for housing. Land policy determines where and how future developments take place, and as a result, it has a considerable impact on both supply and demand of housing. Municipalities use different strategies of land policy to pursue housing goals. This paper aims to explore the rationalities underpinning such strategies of land policy. Therefore, a theory on pluralism – Cultural Theory – is employed to understand municipal strategies in different contexts, i.e. Germany (Ruhr region), Belgium (Flanders), and Netherlands. Applying Cultural Theory to land policy results in four ideal-typical strategies of active, passive, reactive, and protective land policies. Despite the fact that the decisions of municipalities are made within (or constrained by) their institutional environments (i.e. national/regional planning systems, development cultures, etc.), we found that there are key similarities between the strategies of the studied municipalities regardless of their different institutional environments.

    Chemical pollution imposes limitations to the ecological status of European surface waters
    Posthuma, Leo ; Zijp, Michiel C. ; Zwart, Dick De; Meent, Dik Van de; Globevnik, Lidija ; Koprivsek, Maja ; Focks, Andreas ; Gils, Jos Van; Birk, Sebastian - \ 2020
    Scientific Reports 10 (2020)1. - ISSN 2045-2322

    Aquatic ecosystems are affected by man-made pressures, often causing combined impacts. The analysis of the impacts of chemical pollution is however commonly separate from that of other pressures and their impacts. This evolved from differences in the data available for applied ecology vis-à-vis applied ecotoxicology, which are field gradients and laboratory toxicity tests, respectively. With this study, we demonstrate that the current approach of chemical impact assessment, consisting of comparing measured concentrations to protective environmental quality standards for individual chemicals, is not optimal. In reply, and preparing for a method that would enable the comprehensive assessment and management of water quality pressures, we evaluate various quantitative chemical pollution pressure metrics for mixtures of chemicals in a case study with 24 priority substances of Europe-wide concern. We demonstrate why current methods are sub-optimal for water quality management prioritization and that chemical pollution currently imposes limitations to the ecological status of European surface waters. We discuss why management efforts may currently fail to restore a good ecological status, given that to date only 0.2% of the compounds in trade are considered in European water quality assessment and management.

    Monitoring van insectenpopulaties in Nederland : Visie en aanpak voor de realisatie van een monitorings- en onderzoeksprogramma naar de ontwikkelingen van insectenpopulaties in Nederland
    Schmidt, A.M. ; Meij, T. van der - \ 2020
    Wageningen : Wageningen Environmental Research (Rapport / Wageningen Environmental Research 3016) - 63
    n response to the article of Hallman et al . (2017) on the drastic decline in biomass of insects in 31 natural reserves in Germany and the subsequent report of Kleijn et al. (2018) on the data and knowledge gaps on the trends in insect populations in The Netherlands a debate was carried out by the house of representatives. During this debate a motion was filed and accepted on the development of long-term monitoring and research program on the trends in insect populations in agricultural areas. In response to this the Ministry of Agriculture, Nature and Food Quality asked Wageningen Environmental Research to develop a vision and a plan of action for the monitoring of insects in The Netherlands. The starting points of this vision, apart from the existing biodiversity policy, are the foreseen transition in the agricultural sector as mentioned in the vision of the Minister of Agriculture, Natura and Food Quality on the circular agriculture and the expected contribution to the conservation and restoration of biodiversity. In doing so the connection and coherence between agriculture and nature has been given special attention, as most of the biodiversity is restricted to natural areas and natural areas are of utmost importance for the restoration of biodiversity in agricultural areas. A comprehensive set of indicators is proposed based on the three dimensions of a nature inclusive circular agriculture, namely caring for the conservation and restoration of biodiversity, better use of functional biodiversity and lowering the impact on biodiversity. A first proposal has been made how to operationalize these indicators and how to make use of existing monitoring programs, plans/initiatives and pilots.
    Biases in bulk: DNA metabarcoding of marine communities and the methodology involved
    Loos, Luna M. van der; Nijland, Reindert - \ 2020
    Molecular Ecology (2020). - ISSN 0962-1083
    biodiversity - DNA metabarcoding - marine monitoring - technical biases

    With the growing anthropogenic pressure on marine ecosystems, the need for efficient monitoring of biodiversity grows stronger. DNA metabarcoding of bulk samples is increasingly being implemented in ecosystem assessments and is more cost-efficient and less time-consuming than monitoring based on morphology. However, before raw sequences are obtained from bulk samples, a profound number of methodological choices must be made. Here, we critically review the recent methods used for metabarcoding of marine bulk samples (including benthic, plankton and diet samples) and indicate how potential biases can be introduced throughout sampling, preprocessing, DNA extraction, marker and primer selection, PCR amplification and sequencing. From a total of 64 studies evaluated, our recommendations for best practices include to (a) consider DESS as a fixative instead of ethanol, (b) use the DNeasy PowerSoil kit for any samples containing traces of sediment, (c) not limit the marker selection to COI only, but preferably include multiple markers for higher taxonomic resolution, (d) avoid touchdown PCR profiles, (e) use a fixed annealing temperature for each primer pair when comparing across studies or institutes, (f) use a minimum of three PCR replicates, and (g) include both negative and positive controls. Although the implementation of DNA metabarcoding still faces several technical complexities, we foresee wide-ranging advances in the near future, including improved bioinformatics for taxonomic assignment, sequencing of longer fragments and the use of whole-genome information. Despite the bulk of biases involved in metabarcoding of bulk samples, if appropriate controls are included along the data generation process, it is clear that DNA metabarcoding provides a valuable tool in ecosystem assessments.

    Elimination of epidermal wax from explants increases growth in tissue culture of lily
    Askari, Naser ; Klerk, Geert Jan De - \ 2020
    Scientia Horticulturae 274 (2020). - ISSN 0304-4238
    Contamination - Epidermis - Lily - Scale - Uptake - Wax

    The aerial parts of plants are covered by the cuticle, a skin containing among others waxes. The cuticle inhibits the outflow of compounds, in particular water, from the plant to the environment, and without a cuticle, plants dehydrate rapidly. In the cuticle, waxes are the chief actors in the blocking. In tissue culture, the humidity in the headspace is very high (close to 100 %) so evaporation is limited and the cuticle is less needed. The cuticle also inhibits the entry of compounds from the environment into plants. In tissue culture, the inflow of medium components occurs predominantly via wounds, primarily those made when explants are cut. The removal of the barrier is expected to enhance the uptake of medium components. This paper addresses the question as to whether the removal of the epidermal inflow barrier enhances growth in tissue culture of lily. Waxes were removed from scale explants by a short rinse (5 s) with chloroform. During this rinse, the stomata had to be closed since otherwise the tissue was severely damaged by the inflow of chloroform into the cavities below the stomata. The closure was achieved by an abscisic acid (ABA) pre-treatment. Removal of wax resulted in increased growth (50 %) relative to nonchloroform-treated explants. This procedure is, however, not suitable for practical application because the benefit was undone by an inhibitory effect of the ABA pre-treatment. The ABA pre-treatment also increased the percentage of contaminated cultures, probably because during surface-sterilization the disinfectant did not reach the contaminants inhabiting the cavities below the stomata when the stomata had been closed.

    Knowledge translation in project portfolio decision-making: the role of organizational alignment and information support system in selecting innovative ideas
    Annosi, Maria Carmela ; Marchegiani, Lucia ; Vicentini, Francesca - \ 2020
    Management Decision 58 (2020). - ISSN 0025-1747
    Innovative ideas - Knowledge transfer - Knowledge translation - Organizational alignment - Project portfolio management

    Purpose: The present study aims to describe the micro-dynamics of decision-making that refer to knowledge translation pursued by organizational actors to see how they affect the travel of new ideas within the managerial practice of Project Portfolio Management (PPM). The study focuses on how the alignment of actors' meanings is reached at the organizational level and how they move towards a common direction by synthesizing information and negotiating meanings across the activities that constitute PPM. The study also investigates the intermediation function of information support systems in knowledge translation, which brokers information among those involved in the PPM practice. Design/methodology/approach: This piece of research uses an inductive, qualitative research approach and a methodological combination of case study research and grounded theory to investigate and explore the processes of knowledge transfer and translation enacted by the organizational actors (both human and non-human) involved in innovation portfolio decision-making. Findings: The findings of this research reveal the sequence of portfolio decision-making process that confirms that PPM occurs not only in a single hierarchical level or meeting, but that decisions are made across different organizational levels in a complex network of relationships where many actors are involved. We also show that the technological artefacts have an intermediate role in knowledge translation. Research limitations/implications: Despite referring to a single case study, the results discussed in this piece of research provides insightful evidence for academics and practitioners alike. In fact, the paper discusses organizational pre-alignment and alignment as a crucial enabler of knowledge transfer. Moreover, the intermediate role of an information support system is discussed. Practical implications: Our study highlights the positive effect on actors' meaningful participation in PPM associated with the adoption of information support systems in PPM. Moreover, our results highlight the importance of considering a horizontal perspective in the decision-making process, so that knowledge translation occurs by leveraging on all the actors' breadth of experience and expertise. Originality/value: This research emphasizes two organizational routines termed as decision- making preparation processes that were identified as key enablers of portfolio decision-making: cross-functional pre-alignment and an information support system.

    Bamboo composites
    Keijsers, E.R.P. - \ 2020
    Wageningen : Wageningen Food & Biobased Research (Report / Wageningen Food & Biobased Research 2084) - ISBN 9789463955232 - 18
    This report describes the research that has been performed by Wageningen Food & Biobased Research on the development of bamboo composites from Bamboo from Ethiopia. This research is part of the INBAR DUTCH-Sino program. Currently the industry in Ethiopia is producing bamboo panels and bamboo stick based products – blinds, tooth picks, incense sticks. Plastic composite panels would be a new option for bamboo products in Ethiopia. Based on existing knowledge of plastic composite production processes an overview of possible processes and plastics matrix material is given. Ideally, plastic waste streams from Ethiopia would be used as plastic matrix, however, the plastic polymer type of two major large waste streams, PET bottles and PE bags and foils is considered not suited as plastic matrix for plastic fibre composites. Lab-scale tests have been performed on fine and course residues from current bamboo stick industry (based on highland and lowland bamboos) and on milled samples from top, middle and bottom parts of highland and lowland bamboo. Injection moulded composites were produced base on 30wt% of bamboo combined with a commercial grade polypropene (67 wt%) and a commercial coupling agent (3 wt%). Mechanical testing results show that all types of bamboo sources can be used to produce composites. On average, the composites of highland bamboo had slightly lower mechanical properties than lowland bamboo. The bending stiffness of the fine and course residues was slightly lower than the unprocessed bamboo samples. However, differences are small. Some considerations and recommendations concerning the development of bamboo composite panels are made, highlighting the differences with the current bamboo stick industry in Ethiopia. Current industry is labour intensive and the process is robust, the processes can be halted and restarted at any moment, water content/dryness of the bamboo is not extremely critical. The production process for bamboo composites is capital intensive. The process should be run continuously to prevent losses on start-up and shut down. Moisture content of the fibres needs to be controlled, ideally production should be performed under climate controlled conditions in the work space.
    Verkenning maximaal haalbarekwaliteiten gerecyclede PET uit schalen : Praktische studie naar de maximaal haalbare kwaliteit van mechanisch gerecyclede PET uitschalen
    Thoden van Velzen, E.U. ; Smeding, I.W. ; Molenveld, K. - \ 2020
    Wageningen : Wageningen Food & Biobased Research (Rapport / Wageningen Food & Biobased Research 2069) - ISBN 9789463954662 - 37
    Dit rapport beschrijft een technische verkenning naar de maximaal haalbare kwaliteit gerecycled poly(ethyleen tereftalaat) (rPET) die verkregen kan worden uit PET-schalen met een mechanisch recyclingproces. PET is een veel gebruikt verpakkingsmateriaal voor verschillende verse levensmiddelen als vlees, vis, kaas, maaltijdsalades, noten, etc. Voor flessen zijn goed functionerende mechanische recyclingprocessen ontwikkeld waarmee food-grade rPET wordt verkregen. Voor de grotere markt van PET-schalen is dit tot nu toe nog niet op industriële schaal gelukt, ondanks meerdere pogingen door verschillende bedrijven. Deze pogingen om uit het sorteerproduct PET-schalen PET te recyclen zijn tot nu toe gestrand op te lage massa-opbrengsten PET-product, teveel afvalstromen en een te lage kwaliteit van het eindproduct. PET-schalen zijn een ingewikkelde grondstof: ze zijn divers in grootte, kleur en samenstelling. Bovendien bestaan PET-schalen uit meerdere componenten en materialen. Mede hierdoor zijn er ook problemen met de kwaliteit van het gerecyclede PET materiaal, die de toepasbaarheid van het gerecyclede PET-materiaal aanzienlijk beperken. Om te bepalen wat de maximaal haalbare kwaliteit gerecycled PET uit schalen is, werden vier soorten schone PET-schalen getest in dit onderzoek. Het ging hier om mono-PET-schalen, maar ook om schalen met een sealmedium, een PE-laag of een rest top-folie. Al deze soorten schalen werden apart van elkaar gemalen, gedroogd, geëxtrudeerd en spuit-gegoten tot testsamples. De materiaaleigenschappen van deze mechanisch gerecyclede schalen-PET-soorten werden bestudeerd in relatie tot de samenstelling van de ingaande PET-schalen. Hieruit bleek dat gerecycled PET gemaakt van zuivere PET-schalen, waaraan dus geen sealmedium is toegevoegd, transparant en nauwelijks gekleurd is. Helaas was de intrinsieke viscositeitswaarde van dit soort gerecycled PET veel te laag, waardoor het materiaal te bros wordt. Dit materiaal zal eerst een nacondensatie-proces moeten ondergaan. Hierna zal dit materiaal sterker zijn, eenvoudiger te verwerken en breder toe te passen. Een andere en aanvullende optie om de intrinsieke viscositeit te verhogen is bijmengen met nieuw PET. In het geval de grondstof voor recycling nog een sealmedium of een restant top-folie bevat, wordt het gerecyclede PET grijs en ondoorzichtig. De intrinsieke viscositeitwaarden voor deze typen gerecycled PET waren wel iets beter, maar eigenlijk nog steeds te laag om goed te kunnen verwerken. Ook deze soorten gerecycled PET zullen dus een nacondensatie moeten ondergaan. Voor deze soorten gerecycled PET bestaat momenteel geen markt van betekenis. Deze resultaten laten zien dat de gewenste kwaliteit van transparante gerecyclede PET alleen kan worden verkregen uit PET-schalen die ook echt alleen uit PET bestaan en waaraan dus geen andere materialen zijn toegevoegd. Dit betekent dat PET-schalen die ontworpen worden voor mechanische recycling alleen uit PET mogen bestaan en uit andere verpakkingscomponenten (zoals labels) die met zeer hoge efficiëntie kunnen worden afgescheiden tijdens het wasproces. Overigens is de afwasbaarheid van verpakkingscomponenten niet onderzocht in deze studie, aangezien dit buiten de opdrachtbeschrijving valt. Deze studie opent – op basis van de eigenschappen van het gerecyclede materiaal - mogelijkheden voor de mechanische recycling van een deel van de PET-schalen. Het gaat om het deel waarvoor een gegarandeerde luchtdichte afsluiting niet noodzakelijk is, en waarvoor dus geen sealmedium nodig is, zoals bij klemdeksels voor druiven, tomaten, zacht-fruit, noten, etc. Voor PET-schalen die wel gegarandeerd luchtdicht afgesloten moeten worden (vlees, vis, kaas, vleeswaar, vleesvervangers, etc.) is een seal-systeem nodig dat of verenigbaar is met PET of volledig afgescheiden kan worden in het mechanische recyclingproces. Om verder te komen met de mechanische recycling van PET-schalen is meer onderzoek naar een dergelijk sealsysteem en de afwasbaarheid daarvan in een mechanisch recyclingproces noodzakelijk. In de tussentijd kan alleen een beperkte hoeveelheid PET-schalen mechanisch worden gerecycled mits er een sorteertechnologie wordt ontwikkeld om de zuivere PET-schalen uit het mengsel van PET-schalen te halen. Los hiervan, blijven er nog uitdagingen met het beperkte massa-rendement van het mechanische recycling proces.---A technical exploration study has been executed to define the maximal achievable quality of recycled poly(ethylene terephthalate) (rPET) that can be made from PET trays with a standard mechanical recycling process. PET is a versatile packaging material used to package multiple fresh food products such as meat, fish, cheese, salads, nuts, etc. Multiple recycling processes have been developed for PET bottles that deliver food-grade rPET. For the larger market of PET trays this has not been successful, yet, on an industrial scale, despite multiple attempts by various companies. The attempts to process the sorted product PET trays into recycled PET have failed because of low mass yields for the PET product, large volumes of waste being generated and insufficient quality of the final product. Sorted PET trays are a complicated feedstock. It is heterogeneous in size, colour and composition. Moreover, PET trays are composed of multiple components and materials. This translates in quality issues with the recycled PET material, which limit the applicability of the PET material largely. To determine the maximum achievable quality of rPET that can be made from trays, four types of trays were studied. It involved PET trays that were composed of only PET, but also PET trays with a sealing layer on the flange, PET trays with a PE coating on the inside and PET trays with sealing layers and residues of top-film. All these trays were separately comminuted, dried, extruded and injection moulded into test specimen. The material properties of the mechanically recycled PET trays were studied in relation to the composition of the feedstock trays. This revealed that recycled PET made from pure PET trays, to which no seal medium has been added, is transparent and hardly coloured. The intrinsic viscosity of this type of recycled PET is unfortunately too low, which results in a brittle material. This material will first have to be subjected to a solid-state post-condensation process. This will make the material stronger, easier to process and wider applicable. An additional and alternative option to increase the intrinsic viscosity is to mix with virgin PET. In case the feedstock contains a seal medium or a residue of top-film the rPET turns grey and hazy. Although the intrinsic viscosities of these types of rPET were slightly better, they are still too low to process the material smoothly. Also these types of rPET will need to be subjected to solid state postcondensation. For these types of recycled PET there is currently no market of significance. These results show that the desired quality of transparent recycled PET can only be obtained from PET trays that are solely composed of PET and to which no other material has been added. This implies that PET trays that are designed for mechanical recycling are only allowed to be composed of PET and the packaging components (such as labels) should be removed during recycling with very high separation efficiencies. The removal efficiency of packaging components during the washing step of the recycling process was not analysed, as this fell outside the scope of this study. According to this study the mechanical recycling should be possible for the subset of PET trays that does not rely on a gas tight closure of the trays, such as clam shells for grapes, tomatoes, soft fruit, nuts, etc. For PET trays used in modified atmosphere packages, that hence need to be sealed hermetically (meat, fish, cheese, cured meats, meat replacements, etc.), first a sealing system is required that is either compatible with PET or can be completely removed during recycling. To progress with the mechanical recycling of PET trays, further research into such a sealing system, including its removal during a mechanical recycling process, is paramount. In the meantime, only a limited amount of PET trays can be mechanically recycled, provided that a sorting technology is developed that can sort out pure PET trays from a mixture of PET trays. Besides these challenges, also the limited mass yield of the mechanical recycling process for PET trays has to be resolved.
    The distribution of food security impacts of biofuels, a Ghana case study
    Brinkman, Marnix ; Levin-Koopman, Jason ; Wicke, Birka ; Shutes, Lindsay ; Kuiper, Marijke ; Faaij, André ; Hilst, Floor van der - \ 2020
    Biomass and Bioenergy 141 (2020). - ISSN 0961-9534
    Biofuel mandate - CGEmodel - Developing country - Food security - Household - Nutrition

    The demand for biofuels is expected to increase significantly in the coming years. However, there are major concerns on the impact of increased biofuel production on food security. As biofuel affects food security in various ways, it is important to assess the impacts on the four pillars of food security, availability, access, utilisation and stability. The objective of this study is to ex-ante quantify impacts of biofuel production on the four pillars of food security for urban and rural households in a developing country. We illustrate this for Ghana, which proposed a 10% biodiesel and 15% ethanol mandate for 2030 and which faces food security issues. We used the computable general equilibrium (CGE) model MAGNET in combination with a household and a nutrition module to quantify 13 food security indicators. The results show that the largest food security effects of the biofuel mandate are negative impacts on food prices and import dependency. However, the projected food security impacts of the biofuel mandate in 2030 are relatively small compared to the projected food security effects of economic development in Ghana towards 2030. Our approach enables ex-ante quantification of the effects of biofuel on the four pillars of food security and the differentiation of the effects between urban and rural households. Although improvements can be made, the approach means a big step forward compared to the state-of-the-art knowledge on food security impacts of biofuel production and it could contribute to identify options to minimise negative and optimise positive food security effects.

    Impacts of thermal and non-thermal processing on structure and functionality of pectin in fruit- and vegetable- based products:A review
    Liu, Jianing ; Bi, Jinfeng ; McClements, David Julian ; Liu, Xuan ; Yi, Jianyong ; Lyu, Jian ; Zhou, Mo ; Verkerk, Ruud ; Dekker, Matthijs ; Wu, Xinye ; Liu, Dazhi - \ 2020
    Carbohydrate Polymers 250 (2020). - ISSN 0144-8617
    Bioactive compounds - Enzymatic pectin depolymerization - High hydrostatic pressure - High pressure homogenization - Modification - Ultrasound

    Pectin, a major polysaccharide found in the cell walls of higher plants, plays major roles in determining the physical and nutritional properties of fruit- and vegetable-based products. An in-depth understanding of the effects of processing operations on pectin structure and functionality is critical for designing better products. This review, therefore, focuses on the progress made in understanding the effects of processing on pectin structure, further on pectin functionality, consequently on product properties. The effects of processing on pectin structure are highly dependent on the processing conditions. Targeted control of pectin structure by applying various processing operations could enhance textural, rheological, nutritional properties and cloud stability of products. While it seems that optimizing product quality in terms of physical properties is counteracted by optimizing the nutritional properties. Therefore, understanding plant component biosynthesis mechanisms and processing mechanisms could be a major challenge to balance among the quality indicators of processed products.

    Overview of existing knowledge concerning food behaviourinterventions out-of-home, in the working environment and in health care settings : a literature review
    Reinders, Machiel ; Bouwman, Emily ; Taufik, Danny - \ 2020
    Wageningen : Wageningen Economic Research - 105
    So-called ‘closed settings’, like restaurants, canteens, hospitals and other out-of-home locations, can play an important role in improving diet quality by offering healthier and more sustainable food choices (i.e., more vegetables, less meat) on their menus. This report aims to provide an overview of different real-life interventions focused on food choice behaviour of consumers in these closed settings. For this purpose, a review of the literature has been conducted with a main focus on interventions promoting healthy and sustainable food choicesinthree real-life closed settings, namely out-of-home, the working environmentand health care settings. This deliverable provides insight into which type of behavioural interventions have been tested and are particularly effective in stimulating healthy and/or sustainable food choices in each of these settings. The overview is based on 79 studies in total (out-of-home: 24; working environment: 33; health care: 22), that were found by doing a literature search in the database Web of Science. Results show that across the three settings, the large majority of the interventions were through an environmental intervention,for example a type of nudging, and fewer studies used and tested some form of education/information provision. More specifically, in the settings out-of-homeand working environment most interventions tested a type of nudging strategy to stimulate healthy and/or sustainable food choices. In the health caresetting, studies consisted mostly of a type of environmental intervention, where modifications were made in, for example, the way menus were offered or the type of offered products was altered. Across settings, most studies were successful in influencing their outcome variable of interest. Overall, multi-component studies appear to be somewhat more successful than single-component interventions. In both out-of-homeand working environment settings, studies that use priming nudges (i.e., by means of visibility, accessibility and availability) seem to be most successful, whereas mixed results were found for salience nudges (i.e., colour-coded labelling appeared to be more effective than calorie labelling). In the health caresetting, environmental interventions were more successful than educational interventions. Specifically, the environmental studies using salience nudges, by means of labelling and verbal prompts, were effective. Priming nudges by means of accessibility (i.e., an alternative menu-ordering system) and visibility (enhancing ambiance) were also effective. Note that, although the studies that are described in this deliverable are based on a thorough assessment of the literature, it cannot be labelled as a systematic review as it did not follow all necessary steps that are needed to qualify as a systematic review. The articles described depend on the search criteria that were set for the literature search. Therefore it is possible that some relevant studies might be missing. Nevertheless, this literature review gives an overview of which intervention components are particularly effective in stimulating healthy and/or sustainable food choices in each of the settings. This overview can be helpful for practitioners who want to stimulate healthy and sustainable food choices within closed settings, like caterers, restaurant owners, health care staff, employers or other providers of food. Additionally, this overview can be helpfulfor researchers who are interested or want to develop an intervention in one of these settings. This report is an update of the report 'Overview of existing knowledge concerning food behaviourinterventions out-of-home, in the working environment and in online settings' from the PPP project Food, Value, Impact with input from the PPP projectImplementation of food interventions in health care and out of home(in Dutch: Implementatie van voedingsinterventies in intramurale zorginstellingen en horeca).
    The role of staff in food behaviourinterventions in out-of-home and health care settings -an overview of existing literature
    Taufik, Danny ; Jaspers, Patricia ; Bouwman, Emily ; Reinders, Machiel - \ 2020
    Wageningen : Wageningen Economic Research - 61
    In this deliverable of the PPP projectImplementatie van voedingsinterventies in intramurale zorginstellingen en horeca an overview is made of the role of staff in conducting interventions promoting healthy and sustainable food choices in out-of-home and health care settings. This deliverable provides insight into the role of the staff in behavioural interventions and what the barriers and supporting factors are for the staff to implement the intervention in these settings. The overview is based on 17 studies in total, that were found by doinga literature search in the database Web of Science. Results show that in the health care setting most studies are conducted in either a hospital or a nursing home. The role of the staff in the intervention was mainly that they had to undergo training, coaching and/or education. Main barriers of the staff to implementthe intervention are a lack of time, a lack of staff capacity and inflexibility of the food service system. Main supporting factors are satisfaction of the staff with the intervention and the involvement with patients as a result of the intervention. In the out-of-home setting most studies are conducted in a school setting. The role of the staff was mainly training in how to promote and prepare healthy food and educating about the consequences of unhealthy cooking. Main barriers for staff to implement the intervention are a lack of time, having to participate in a training, lack of communication from the managers to the staff and amongst staff members about execution of the intervention and negative perceptions of the staff towards the intervention. Supporting factors are positiveperceptions towards the intervention and knowledge of the intervention and the benefits for the target group. Taken together, some of the types of barriers and facilitators recur in both settings. A main barrier that is mentioned for bothsettings is lack of time. Other overlapping barriers were lack of staff, other competing priorities, negative perceptions of staff toward the intervention, a lack of support and a lack of communication to and amongst staff about the intervention. Facilitators that were similar across settings were satisfaction of the staff with the training, positiveperceptions towards the intervention, knowledge of the intervention and the benefits for the target group, being confident to make changes and, finally, the presence of incentives. The observed similarities in the twodifferent settings, might be an indication that these barriers and facilitators are important aspects to consider in implementing an intervention in other closed settings as well. Stated differently, withinthis study the settings health care and out of home were the focus, but it could be possible that the found barriers and facilitators also apply in other closed settings. This overview cannot only be helpful for researchers who are involved in the project Implementatie van voedingsinterventies in intramurale zorginstellingen en horeca, but alsoforthosewho are interested in developing or implementing real-life food interventions in a health care or out-of-home setting or other settings. Furthermore, this overview might be relevant for the management of these settings, as it provides information on critical success factors of implementing interventions, i.e. barriers amongst staff that need to be overcome as well as supporting factors that can be helpful in successfully implementing the interventions. Note that the studies described in this report depend on the search criteria that were set for the literature search. Therefore it is possible that some relevant studies might be missing. Nevertheless, we believe that this literature review gives an overview of how staff can be motivated to implement an intervention.
    Lobster fisheries in the Oosterschelde : An overview of biology, management & available data
    Overmaat, Wiske ; Post, Stefan ; Spoor, Lianne - \ 2020
    IJmuiden : Wageningen Marine Research (Wageningen Marine Research rapport C075/20) - 47
    Lobsters have been fished in the Oosterschelde since 1881. The so-called Oosterschelde lobster (Homarus gammarus) is very popular with the consumer, but little is known about the lobster fishery. This report summarises the available data on the lobster fishery. The study was carried about by students of University of Applied Sciences Van Hall Larenstein Leeuwarden, as part of the Bachelors' programme Kust en Zee Management. The three main questions are: What do we know about lobster biology, how is the lobster fishery currently managed and what data is available? The research project was commissioned in cooperation between the fishing association OWV (Vereniging van Beroepsvissers op de Oosterschelde, Voordelta en Westerschelde) and Wageningen Marine Research, as part of preparations for a research grant proposal towards the development of a stock assessment. For implementing optimal management and to develop a stock assessment of the lobster population in the Oosterschelde in future, it is necessary to obtain a detailed overview of the current situation. A literature study was conducted and six lobster fishers who fish in the Oosterschelde were interviewed for this study. The fishers were asked to share information about their use of fishing gear, their license, how much lobster they catch and their views on the development of the lobster stock. In the Oosterschelde, there are 42 active lobster fishing licenses, of which 37 are affiliated with the fishing association OWV. Two years ago, a major change was made in the system. The "lobster race" has been changed into a lottery system, organized by OWV. This lottery system is an improvement in the lobster sector, as with the new system every lobster fisher has equal opportunities. The abundance of lobster varies due to natural factors, but a continuing downward trend has been observed in recent years by lobster fishers and recreational divers. An overview of available data on the stock is shown in Table 2, but these have not been structurally analysed. The observed downward trends can therefore not be explained. An overview of the different views on stock decline by interviewed fishers can be found in Table 4 and 5. Since the exact reasons for the declining lobster population are unknown, no focused action or policy can be undertaken and made. Plans to reduce the number of licences to reduce fishing effort and increase the economic viability failed in 2015 after a process of ten years. There was no stock assessment to base these decisions on, and lack of support to carry out the proposed changes. The study leads to four recommendations: 1. The early benthic phase (EBP) of the lobster is not feasible to use in a future stock assessment. Assessing larger individuals will give a more reliable view of the lobster population in the Oosterschelde; 2. Further research should be carried out into which natural and anthropogenic factors (Table 4 and 5) impact lobster stocks in the Oosterschelde; 3. A survey should be held among all lobster fishers to further improve insights into the perceptions on stock development and management as well as their willingness to contribute to future data collection projects. This will inform the development of a stock assessment and research priorities. 4. Communications between the fishers and the Ministry of Agriculture, Nature and Food Quality in relation to monitoring of (illegal) fishing activities should be improved.
    A Cloud-Based Environment for Generating Yield Estimation Maps From Apple Orchards Using UAV Imagery and a Deep Learning Technique
    Apolo-Apolo, Orly Enrique ; Pérez-Ruiz, Manuel ; Martínez-Guanter, Jorge ; Valente, João - \ 2020
    Frontiers in Plant Science 11 (2020). - ISSN 1664-462X
    apple - deep learning - fruit - Google Colab - photogrammetry - yield map

    Farmers require accurate yield estimates, since they are key to predicting the volume of stock needed at supermarkets and to organizing harvesting operations. In many cases, the yield is visually estimated by the crop producer, but this approach is not accurate or time efficient. This study presents a rapid sensing and yield estimation scheme using off-the-shelf aerial imagery and deep learning. A Region-Convolutional Neural Network was trained to detect and count the number of apple fruit on individual trees located on the orthomosaic built from images taken by the unmanned aerial vehicle (UAV). The results obtained with the proposed approach were compared with apple counts made in situ by an agrotechnician, and an R2 value of 0.86 was acquired (MAE: 10.35 and RMSE: 13.56). As only parts of the tree fruits were visible in the top-view images, linear regression was used to estimate the number of total apples on each tree. An R2 value of 0.80 (MAE: 128.56 and RMSE: 130.56) was obtained. With the number of fruits detected and tree coordinates two shapefile using Python script in Google Colab were generated. With the previous information two yield maps were displayed: one with information per tree and another with information per tree row. We are confident that these results will help to maximize the crop producers' outputs via optimized orchard management.

    A cross-scale assessment of productivity–diversity relationships
    Craven, Dylan ; Sande, Masha T. van der; Meyer, Carsten ; Gerstner, Katharina ; Bennett, Joanne M. ; Giling, Darren P. ; Hines, Jes ; Phillips, Helen R.P. ; May, Felix ; Bannar-Martin, Katherine H. ; Chase, Jonathan M. ; Keil, Petr - \ 2020
    Global Ecology and Biogeography (2020). - ISSN 1466-822X
    biodiversity–ecosystem function - biomass - climate - machine learning - more individuals hypothesis - spatial grain - species–energy relationship

    Aim: Biodiversity and ecosystem productivity vary across the globe, and considerable effort has been made to describe their relationships. Biodiversity and ecosystem functioning research has traditionally focused on how experimentally controlled species richness affects net primary productivity (S → NPP) at small spatial grains. In contrast, the influence of productivity on richness (NPP → S) has been explored at many grains in naturally assembled communities. Mismatches in spatial scale between approaches have fuelled debate about the strength and direction of biodiversity–productivity relationships. Here, we examine the direction and strength of the influence of productivity on diversity (NPP → S) and the influence of diversity on productivity (S → NPP) and how these vary across spatial grains. Location: Contiguous USA. Time period: 1999–2015. Major taxa studied: Woody species (angiosperms and gymnosperms). Methods: Using data from North American forests at grains from local (672 m2) to coarse spatial units (median area = 35,677 km2), we assess relationships between diversity and productivity using structural equation and random forest models, while accounting for variation in climate, environmental heterogeneity, management and forest age. Results: We show that relationships between S and NPP strengthen with spatial grain. Within each grain, S → NPP and NPP → S have similar magnitudes, meaning that processes underlying S → NPP and NPP → S either operate simultaneously or that one of them is real and the other is an artefact. At all spatial grains, S was one of the weakest predictors of forest productivity, which was largely driven by biomass, temperature and forest management and age. Main conclusions: We conclude that spatial grain mediates relationships between biodiversity and productivity in real-world ecosystems and that results supporting predictions from each approach (NPP → S and S → NPP) serve as an impetus for future studies testing underlying mechanisms. Productivity–diversity relationships emerge at multiple spatial grains, which should widen the focus of national and global policy and research to larger spatial grains.

    EUNIS Habitat Classification: Expert system, characteristic species combinations and distribution maps of European habitats
    Chytrý, Milan ; Tichý, Lubomír ; Hennekens, Stephan M. ; Knollová, Ilona ; Janssen, John A.M. ; Rodwell, John S. ; Peterka, Tomáš ; Marcenò, Corrado ; Landucci, Flavia ; Danihelka, Jiří ; Hájek, Michal ; Dengler, Jürgen ; Novák, Pavel ; Zukal, Dominik ; Jiménez-Alfaro, Borja ; Mucina, Ladislav ; Abdulhak, Sylvain ; Aćić, Svetlana ; Agrillo, Emiliano ; Attorre, Fabio ; Bergmeier, Erwin ; Biurrun, Idoia ; Boch, Steffen ; Bölöni, János ; Bonari, Gianmaria ; Braslavskaya, Tatiana ; Bruelheide, Helge ; Campos, Juan Antonio ; Čarni, Andraž ; Casella, Laura ; Ćuk, Mirjana ; Ćušterevska, Renata ; Bie, Els De; Delbosc, Pauline ; Demina, Olga ; Didukh, Yakiv ; Dítě, Daniel ; Dziuba, Tetiana ; Ewald, Jörg ; Gavilán, Rosario G. ; Gégout, Jean Claude ; Giusso del Galdo, Gian Pietro ; Golub, Valentin ; Goncharova, Nadezhda ; Goral, Friedemann ; Graf, Ulrich ; Indreica, Adrian ; Isermann, Maike ; Jandt, Ute ; Jansen, Florian ; Jansen, Jan ; Jašková, Anni ; Jiroušek, Martin ; Kącki, Zygmunt ; Kalníková, Veronika ; Kavgacı, Ali ; Khanina, Larisa ; Yu. Korolyuk, Andrey ; Kozhevnikova, Mariya ; Kuzemko, Anna ; Küzmič, Filip ; Kuznetsov, Oleg L. ; Laiviņš, Māris ; Lavrinenko, Igor ; Lavrinenko, Olga ; Lebedeva, Maria ; Lososová, Zdeňka ; Lysenko, Tatiana ; Maciejewski, Lise ; Mardari, Constantin ; Marinšek, Aleksander ; Napreenko, Maxim G. ; Onyshchenko, Viktor ; Pérez-Haase, Aaron ; Pielech, Remigiusz ; Prokhorov, Vadim ; Rašomavičius, Valerijus ; Rodríguez Rojo, Maria Pilar ; Rūsiņa, Solvita ; Schrautzer, Joachim ; Šibík, Jozef ; Šilc, Urban ; Škvorc, Željko ; Smagin, Viktor A. ; Stančić, Zvjezdana ; Stanisci, Angela ; Tikhonova, Elena ; Tonteri, Tiina ; Uogintas, Domas ; Valachovič, Milan ; Vassilev, Kiril ; Vynokurov, Denys ; Willner, Wolfgang ; Yamalov, Sergey ; Evans, Douglas ; Palitzsch Lund, Mette ; Spyropoulou, Rania ; Tryfon, Eleni ; Schaminée, Joop H.J. - \ 2020
    Applied Vegetation Science (2020). - ISSN 1402-2001
    coastal habitat - diagnostic species - distribution map - dune vegetation - European Nature Information System (EUNIS) - European Vegetation Archive (EVA) - expert system - forest - grassland - habitat classification - man-made habitat - shrubland - vegetation database - vegetation plot - wetland

    Aim: The EUNIS Habitat Classification is a widely used reference framework for European habitat types (habitats), but it lacks formal definitions of individual habitats that would enable their unequivocal identification. Our goal was to develop a tool for assigning vegetation-plot records to the habitats of the EUNIS system, use it to classify a European vegetation-plot database, and compile statistically-derived characteristic species combinations and distribution maps for these habitats. Location: Europe. Methods: We developed the classification expert system EUNIS-ESy, which contains definitions of individual EUNIS habitats based on their species composition and geographic location. Each habitat was formally defined as a formula in a computer language combining algebraic and set-theoretic concepts with formal logical operators. We applied this expert system to classify 1,261,373 vegetation plots from the European Vegetation Archive (EVA) and other databases. Then we determined diagnostic, constant and dominant species for each habitat by calculating species-to-habitat fidelity and constancy (occurrence frequency) in the classified data set. Finally, we mapped the plot locations for each habitat. Results: Formal definitions were developed for 199 habitats at Level 3 of the EUNIS hierarchy, including 25 coastal, 18 wetland, 55 grassland, 43 shrubland, 46 forest and 12 man-made habitats. The expert system classified 1,125,121 vegetation plots to these habitat groups and 73,188 to other habitats, while 63,064 plots remained unclassified or were classified to more than one habitat. Data on each habitat were summarized in factsheets containing habitat description, distribution map, corresponding syntaxa and characteristic species combination. Conclusions: EUNIS habitats were characterized for the first time in terms of their species composition and distribution, based on a classification of a European database of vegetation plots using the newly developed electronic expert system EUNIS-ESy. The data provided and the expert system have considerable potential for future use in European nature conservation planning, monitoring and assessment.

    The analysis of perfluoroalkyl substances at ppt level in milk and egg using UHPLC-MS/MS
    Berendsen, B.J.A. ; Lakraoui, F. ; Leenders, L. ; Leeuwen, S.P.J. Van - \ 2020
    Food Additives & Contaminants. Pt. A, Chemistry, Analysis, Control, Exposure & Risk Assessment (2020). - ISSN 1944-0049 - p. 1 - 12.
    Per- and poly-fluorinated substances (PFASs) are man-made chemicals that have been used for a variety of applications and can end up in the food chain. New opinions on the risk assessment were recently published by the European Food Safety Authority, emphasising the need for more sensitive methods. From this, minimum required LOQs for the analytical method for analysis of milk and egg have been calculated for perfluorooctanoic acid (PFOA) and GenX (hexafluoropropylene oxide dimer acid, HFPO-DA). A fully validated method is described for analysis of 13 PFASs, including PFOA and HFPO-DA, in milk and egg. All compounds, except perfluorodecane sulphonate (PFDS), can be quantitatively determined in these matrices with a trueness ranging from 87% to 119% and a relative within-laboratory reproducibility between 12% and 41%. Also the method proved suitable for confirmation of the identity of the individual PFASs. The LOQ for HFPO-DA in milk and egg is 0.05 ng g−1, well below the calculated required LOQ. For PFOA in egg the determined LOQ is 0.025 ng g−1, nicely below the required level of 0.03 ng g−1. In milk the required LOQ was not achieved: 0.005 instead of 0.003 ng g−1. However, on six out of eight days an LOQ of 0.0025 ng g−1 was demonstrated. It is concluded that the required LOQs are achievable when instrument performance is optimal. The current method can be expanded with long chain PFASs by using a cellulose filter instead of the PTFE filter vials. The presented method was applied for a small-scale study in The Netherlands.
    CloudRoots: integration of advanced instrumental techniques and process modelling of sub-hourly and sub-kilometre land–atmosphere interactions
    Vilà-Guerau de Arellano, Jordi ; Ney, Patrizia ; Hartogensis, Oscar ; Boer, Hugo De; Diepen, Kevin Van; Emin, Dzhaner ; Groot, Geiske De; Klosterhalfen, Anne ; Langensiepen, Matthias ; Matveeva, Maria ; Miranda-García, Gabriela ; Moene, Arnold F. ; Rascher, Uwe ; Röckmann, Thomas ; Adnew, Getachew ; Brüggemann, Nicolas ; Rothfuss, Youri ; Graf, Alexander - \ 2020
    Biogeosciences 17 (2020)17. - ISSN 1726-4170 - p. 4375 - 4404.
    The CloudRoots field experiment was designed to obtain a comprehensive observational dataset that includes soil, plant, and atmospheric variables to investigate the interaction between a heterogeneous land surface and its overlying atmospheric boundary layer at the sub-hourly and sub-kilometre scale. Our findings demonstrate the need to include measurements at leaf level to better understand the relations between stomatal aperture and evapotranspiration (ET) during the growing season at the diurnal scale. Based on these observations, we obtain accurate parameters for the mechanistic representation of photosynthesis and stomatal aperture. Once the new parameters are implemented, the model reproduces the stomatal leaf conductance and the leaf-level photosynthesis satisfactorily. At the canopy scale, we find a consistent diurnal pattern on the contributions of plant transpiration and soil evaporation using different measurement techniques. From highly resolved vertical profile measurements of carbon dioxide (CO2) and other state variables, we infer a profile of the CO2 assimilation in the canopy with non-linear variations with height. Observations taken with a laser scintillometer allow us to quantify the non-steadiness of the surface turbulent fluxes during the rapid changes driven by perturbation of photosynthetically active radiation by cloud flecks. More specifically, we find 2 min delays between the cloud radiation perturbation and ET. To study the relevance of advection and surface heterogeneity for the land–atmosphere interaction, we employ a coupled surface–atmospheric conceptual model that integrates the surface and upper-air observations made at different scales from leaf to the landscape. At the landscape scale, we calculate a composite sensible heat flux by weighting measured fluxes with two different land use categories, which is consistent with the diurnal evolution of the boundary layer depth. Using sun-induced fluorescence measurements, we also quantify the spatial variability of ET and find large variations at the sub-kilometre scale around the CloudRoots site. Our study shows that throughout the entire growing season, the wide variations in stomatal opening and photosynthesis lead to large diurnal variations of plant transpiration at the leaf, plant, canopy, and landscape scales. Integrating different advanced instrumental techniques with modelling also enables us to determine variations of ET that depend on the scale where the measurement were taken and on the plant growing stage
    Check title to add to marked list
    << previous | next >>

    Show 20 50 100 records per page

     
    Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.