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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    The influence of tailored risk communication on individual adaptive behaviour
    Attems, Marie Sophie ; Thaler, Thomas ; Snel, Karin A.W. ; Davids, Peter ; Hartmann, Thomas ; Fuchs, Sven - \ 2020
    International Journal of Disaster Risk Reduction 49 (2020). - ISSN 2212-4209
    Adaptive behaviour - Flood risk management - Property level flood risk adaptation measures - Risk communication - Trust

    Hydro-meteorological hazards annually lead to considerable economic losses worldwide. Property level flood risk adaptation (PLFRA) measures have shown to decrease potential damages by floods and other hazards. However, such measures are often implemented inadequately, frequently because of lacking communication between public administration and homeowners. Thus, risk communication systems have been created by multiple actors, ranging from the government to private companies and insurance groups, which have the goal to communicate risks to homeowners and businesses in a tailored manner. Consequently, adaptive behaviour can be triggered by risk communication. This paper conducted a cross-comparison of several risk communication systems which encompassed an output in the shape of a label or guideline, based on semi-structured interviews with relevant experts. One system, the German Hochwasserpass, was focused on in more detail. The results show that risk communication systems should include participatory approaches with experts to trigger adaptive behaviour. However, even in an example including mutual knowledge transfer a gap between knowledge about mitigation measures and actually implementing them was present. Thus, this implies going a step beyond, which ultimately questions the resource efficiency of such risk communication systems on a larger scale.

    Dietary fibre enrichment of supplemental feed modulates the development of the intestinal tract in suckling piglets
    Hees, H.M.J. Van; Davids, M. ; Maes, D. ; Millet, S. ; Possemiers, S. ; Hartog, L.A. Den; Kempen, T.A.T.G. Van; Janssens, G.P.J. - \ 2019
    Journal of Animal Science and Biotechnology 10 (2019)1. - ISSN 1674-9782
    Dietary fibre - Gut maturation - Gut microbiota - Suckling piglets

    Background: Commercial pre-weaning diets are formulated to be highly digestible and nutrient-dense and contain low levels of dietary fibre. In contrast, pigs in a natural setting are manipulating fibre-rich plant material from a young age. Moreover, dietary fibre affects gastrointestinal tract (GIT) development and health in older pigs. We hypothesised that supplemental diets that contain vegetal fibres are accelerating GIT development in suckling piglets in terms of size and functionality. From d 2 of life, sow-suckled piglets had access to a low fibre diet (CON), a diet with a fermentable long-chain arabinoxylan (lc-AXOS), a diet with a largely non-fermentable purified cellulose (CELL), or a diet containing both fibres. During the initial 2 weeks, the control diet was a high-density milk replacer, followed by a dry and highly digestible creep meal. Upon weaning at 25 d, 15 piglets from each treatment group, identified as eaters and originating from six or seven litters, were sacrificed for post-mortem examination of GIT morphology, small intestinal permeability and metabolic profile of the digesta. The microbiota composition of the mid-colon was evaluated in a sub-set of ten piglets. Results: No major statistical interactions between the fibre sources were observed. Piglets consumed the fibre-containing milk supplements and creep diets well. Stomach size and small intestinal permeability was not affected. Large intestinal fill was increased with lc-AXOS only, while relative large intestinal weight was increased with both fibre sources (P < 0.050). Also, CELL decreased ileal pH and tended to increase ileal DM content compared to CON (P < 0.050). Moreover, the concentration of volatile fatty acids was increased in the caecum (P < 0.100) and mid-colon (P < 0.050) by addition of CELL. lc-AXOS only stimulated caecal propionate (P < 0.050). The microbiota composition showed a high individual variation and limited dietary impact. Nonetheless, CELL induced minor shifts in specific genera, with notable reductions of Escherichia-Shigella. Conclusions: Adding dietary fibres to the supplemental diet of suckling piglets altered large intestinal morphology but not small intestinal permeability. Moreover, dietary fibre showed effects on fermentation and modest changes of microbial populations in the hindgut, with more prominent effects from the low-fermentable cellulose.

    1662: Koffie, wereldhandel en de consumptie-revolutie
    Zwart, P. de - \ 2018
    In: Wereldgeschiedenis van Nederland / 't Hart, M., Davids, K., Fatah-Black, K., Heerma van Voss, L., Lucassen, L., Touwen, J., Amsterdam : - ISBN 9789026343995 - p. 275 - 280.
    In Wereldgeschiedenis van Nederland vertellen meer dan honderd aanstormende en gevestigde Nederlandse onderzoekers op het gebied van geschiedenis en cultuur het wereldwijde verhaal van onze geschiedenis, onder wie Martine Gosselink, Beatrice de Graaf, Lotte Jensen, Gert Oostindie, Lodewijk Petram en Suze Zijlstra. In dit verhelderende en prikkelende boek laten zij zien hoe Nederland de wereld door de eeuwen heen mede heeft vormgegeven, en andersom: hoe Nederland zich onder invloed van verre en nabije buren heeft ontwikkeld. Van de vondst van oermens Krijn in de Noordzee tot orkaan Irma op Sint Maarten en van Bonifatius tot Pim Fortuyn – aan de hand van talloze grote en kleine historische ontwikkelingen en gebeurtenissen laat Wereldgeschiedenis van Nederland zien hoezeer Nederland verbonden is met de wereld, en de wereld met Nederland. Wereldgeschiedenis van Nederland is een uitgave van het Huygens Instituut voor Nederlandse Geschiedenis, een knaw-onderzoeksinstituut op het gebied van geschiedenis en literatuur.

    Redactie: Karel Davids, Karwan Fatah-Black, Marjolein ’t Hart, Leo Lucassen en Jeroen Touwen. Hoofdredactie: Lex Heerma van Voss
    1607. De Beemster en het poldermodel
    Cruijningen, P.J. van - \ 2018
    In: Wereldgeschiedenis van Nederland / 't Hart, M., Davids, K., Fatah-Black, K., Heerma van Voss, L., Lucassen, L., Touwen, J., Amsterdam : - ISBN 9789026343995 - p. 207 - 212.
    Metatranscriptome analysis of the microbial fermentation of dietary milk proteins in the murine gut
    Hugenholtz, Floor ; Davids, Mark ; Schwarz, Jessica ; Müller, Michael ; Tomé, Daniel ; Schaap, Peter ; Hooiveld, Guido J.E.J. ; Smidt, Hauke ; Kleerebezem, Michiel - \ 2018
    PLoS ONE 13 (2018)4. - ISSN 1932-6203
    Undigestible food ingredients are converted by the microbiota into a large range of metabolites, predominated by short chain fatty acids (SCFA). These microbial metabolites are subsequently available for absorption by the host mucosa and can serve as an energy source. Amino acids fermentation by the microbiota expands the spectrum of fermentation end-products beyond acetate, propionate and butyrate, to include in particular branched-SCFA. Here the long-term effects of high protein-diets on microbial community composition and functionality in mice were analyzed. Determinations of the microbiota composition using phylogenetic microarray (MITChip) technology were complemented with metatranscriptome and SCFA analyses to obtain insight in in situ expression of protein fermentation pathways and the phylogenetic groups involved. High protein diets led to increased luminal concentrations of branched-SCFA, in accordance with protein fermentation in the gut. Bacteria dominantly participating in protein catabolism belonged to the Lachnospiraceae, Erysipelotrichaceae and Clostridiaceae families in both normal- and high- protein diet regimes. This study identifies the microbial groups involved in protein catabolism in the intestine and underpins the value of in situ metatranscriptome analyses as an approach to decipher locally active metabolic networks and pathways as a function of the dietary regime, as well as the phylogeny of the microorganisms executing them.
    Akkermansia transcriptome response to mucin and/or glucose growth medium
    Ottman, N.A. ; Davids, M. ; Suarez Diez, M. ; Boeren, J.A. ; Schaap, P.J. ; Martins dos Santos, V.A.P. ; Smidt, H. ; Belzer, C. ; Vos, W.M. de - \ 2017
    PRJEB9527 - ERP010638 - Akkermansia muciniphila
    Transcriptome analysis comparing the gene expression of A. muciniphila grown on mucin or glucose media confirmed the activity of the genes involved in mucin degradation, and revealed most of them to be upregulated in the presence of mucin. A. muciniphila grown on glucose showed a stress response and upregulation of specific genes, such as Amuc_1094 which was identified as a glucokinase induced by glucose. The transcriptional response was confirmed by a proteome analysis, reinforcing the adaptation of A. muciniphila to the mucosal environment. These new findings provide molecular insights into the lifestyle of A. muciniphila, and further confirm its role as a mucin specialist in the gut.
    Estimating predictive hydrological uncertainty by dressing deterministic and ensemble forecasts; a comparison, with application to Meuse and Rhine
    Verkade, J.S. ; Brown, J.D. ; Davids, F. ; Reggiani, P. ; Weerts, A.H. - \ 2017
    Journal of Hydrology 555 (2017). - ISSN 0022-1694 - p. 257 - 277.
    Ensemble dressing - Hydrological forecasting - Predictive uncertainty - Quantile Regression - Statistical post-processing

    Two statistical post-processing approaches for estimation of predictive hydrological uncertainty are compared: (i) ‘dressing’ of a deterministic forecast by adding a single, combined estimate of both hydrological and meteorological uncertainty and (ii) ‘dressing’ of an ensemble streamflow forecast by adding an estimate of hydrological uncertainty to each individual streamflow ensemble member. Both approaches aim to produce an estimate of the ‘total uncertainty’ that captures both the meteorological and hydrological uncertainties. They differ in the degree to which they make use of statistical post-processing techniques. In the ‘lumped’ approach, both sources of uncertainty are lumped by post-processing deterministic forecasts using their verifying observations. In the 'source-specific’ approach, the meteorological uncertainties are estimated by an ensemble of weather forecasts. These ensemble members are routed through a hydrological model and a realization of the probability distribution of hydrological uncertainties (only) is then added to each ensemble member to arrive at an estimate of the total uncertainty. The techniques are applied to one location in the Meuse basin and three locations in the Rhine basin. Resulting forecasts are assessed for their reliability and sharpness, as well as compared in terms of multiple verification scores including the relative mean error, Brier Skill Score, Mean Continuous Ranked Probability Skill Score, Relative Operating Characteristic Score and Relative Economic Value. The dressed deterministic forecasts are generally more reliable than the dressed ensemble forecasts, but the latter are sharper. On balance, however, they show similar quality across a range of verification metrics, with the dressed ensembles coming out slightly better. Some additional analyses are suggested. Notably, these include statistical post-processing of the meteorological forecasts in order to increase their reliability, thus increasing the reliability of the streamflow forecasts produced with ensemble meteorological forcings.

    Feasibility of Metatranscriptome Analysis from Infant Gut Microbiota : Adaptation to Solid Foods Results in Increased Activity of Firmicutes at Six Months
    Hugenholtz, Floor ; Ritari, Jarmo ; Nylund, Lotta ; Davids, Mark ; Satokari, Reetta ; Vos, Willem M. De - \ 2017
    International Journal of Microbiology 2017 (2017). - ISSN 1687-918X
    Newborns are rapidly colonized by microbes and their intestinal tracts contain highly dynamic and rapidly developing microbial communities in the first months of life. In this study, we describe the feasibility of isolating mRNA from rapidly processed faecal samples and applying deep RNA-Seq analysis to provide insight into the active contributors of the microbial community in early life. Specific attention is given to the impact of removing rRNA from the mRNA on the phylogenetic and transcriptional profiling and its analysis depth. A breastfed baby was followed in the first six months of life during adaptation to solid food, dairy products, and formula. It was found that, in the weaning period, the total transcriptional activity of Actinobacteria, mainly represented by Bifidobacterium, decreased while that of Firmicutes increased over time. Moreover, Firmicutes and Actinobacteria, including the canonical Bifidobacteria as well as Collinsella, were found to be important contributors to carbohydrate fermentation and vitamin biosynthesis in the infant intestine. Finally, the expression of Lactobacillus rhamnosus-like genes was detected, likely following transfer from the mother who consumed L. rhamnosus GG. The study indicates that metatranscriptome analysis of the infant gut microbiota is feasible on infant stool samples and can be used to provide insight into the core activities of the developing community.
    Genome-scale model and omics analysis of metabolic capacities of Akkermansia muciniphila reveal a preferential mucin-degrading lifestyle
    Ottman, Noora ; Davids, Mark ; Suarez-Diez, Maria ; Boeren, Sjef ; Schaap, Peter J. ; Martins dos Santos, Vitor ; Smidt, Hauke ; Belzer, Clara ; Vos, Willem M. de - \ 2017
    Applied and Environmental Microbiology 83 (2017)18. - ISSN 0099-2240
    Acetate - Akkermansia - Gut microbiota - Metabolic modeling - Mucin - Propionate - Proteomics - Transcriptomics
    The composition and activity of the microbiota in the human gastrointestinal tract are primarily shaped by nutrients derived from either food or the host. Bacteria colonizing the mucus layer have evolved to use mucin as a carbon and energy source. One of the members of the mucosa-associated microbiota is Akkermansia muciniphila, which is capable of producing an extensive repertoire of mucindegrading enzymes. To further study the substrate utilization abilities of A. muciniphila, we constructed a genome-scale metabolic model to test amino acid auxotrophy, vitamin biosynthesis, and sugar-degrading capacities. The model-supported predictions were validated by in vitro experiments, which showed A. muciniphila to be able to utilize the mucin-derived monosaccharides fucose, galactose, and N-acetylglucosamine. Growth was also observed on N-acetylgalactosamine, even though the metabolic model did not predict this. The uptake of these sugars, as well as the nonmucin sugar glucose, was enhanced in the presence of mucin, indicating that additional mucin-derived components are needed for optimal growth. An analysis of whole-transcriptome sequencing (RNA-Seq) comparing the gene expression of A. muciniphila grown on mucin with that of the same bacterium grown on glucose confirmed the activity of the genes involved in mucin degradation and revealed most of these to be upregulated in the presence of mucin. The transcriptional response was confirmed by a proteome analysis, altogether revealing a hierarchy in the use of sugars and reflecting the adaptation of A. muciniphila to the mucosal environment. In conclusion, these findings provide molecular insights into the lifestyle of A. muciniphila and further confirm its role as a mucin specialist in the gut.
    The Variable Regions of Lactobacillus rhamnosus Genomes Reveal the Dynamic Evolution of Metabolic and Host-Adaptation Repertoires
    Ceapa, C.D. ; Davids, M. ; Ritari, Jarmo ; Lambert, J. ; Wels, M. ; Douillard, François P. ; Smokvina, Tamara ; Vos, Willem M. de; Knol, J. ; Kleerebezem, M. - \ 2016
    Genome Biology and Evolution 8 (2016)6. - ISSN 1759-6653 - p. 1889 - 1905.
    Lactobacillus rhamnosus is a diverse Gram-positive species with strains isolated from different ecological niches. Here, we report the genome sequence analysis of 40 diverse strains of L. rhamnosus and their genomic comparison, with a focus on the variable genome. Genomic comparison of 40 L. rhamnosus strains discriminated the conserved genes (core genome) and regions of plasticity involving frequent rearrangements and horizontal transfer (variome). The L. rhamnosus core genome encompasses 2,164 genes, out of 4,711 genes in total (the pan-genome). The accessory genome is dominated by genes encoding carbohydrate transport and metabolism, extracellular polysaccharides (EPS) biosynthesis, bacteriocin production, pili production, the cas system, and the associated clustered regularly interspaced short palindromic repeat (CRISPR) loci, and more than 100 transporter functions and mobile genetic elements like phages, plasmid genes, and transposons. A clade distribution based on amino acid differences between core (shared) proteins matched with the clade distribution obtained from the presence–absence of variable genes. The phylogenetic and variome tree overlap indicated that frequent events of gene acquisition and loss dominated the evolutionary segregation of the strains within this species, which is paralleled by evolutionary diversification of core gene functions. The CRISPR-Cas system could have contributed to this evolutionary segregation. Lactobacillus rhamnosus strains contain the genetic and metabolic machinery with strain-specific gene functions required to adapt to a large range of environments. A remarkable congruency of the evolutionary relatedness of the strains’ core and variome functions, possibly favoring interspecies genetic exchanges, underlines the importance of gene-acquisition and loss within the L. rhamnosus strain diversification
    Adaptation of Akkermansia muciniphila to the oxic-anoxic interface of the mucus layer
    Ouwerkerk, Janneke P. ; Ark, Kees C.H. van der; Davids, Mark ; Claassens, Nico J. ; Finestra, Teresa Robert ; Vos, Willem M. de; Belzer, Clara - \ 2016
    Applied and Environmental Microbiology 82 (2016)23. - ISSN 0099-2240 - p. 6983 - 6993.

    Akkermansia muciniphila colonizes the mucus layer of the gastrointestinal tract, where the organism can be exposed to the oxygen that diffuses from epithelial cells. To understand how A. muciniphila is able to survive and grow at this oxic-anoxic interface, its oxygen tolerance and response and reduction capacities were studied. A. muciniphila was found to be oxygen tolerant. On top of this, under aerated conditions, A. muciniphila showed significant oxygen reduction capacities and its growth rate and yield were increased compared to those seen under strict anaerobic conditions. Transcriptome analysis revealed an initial oxygen stress response upon exposure to oxygen. Thereafter, genes related to respiration were expressed, including those coding for the cytochrome bd complex, which can function as a terminal oxidase. The functionality of A. muciniphila cytochrome bd genes was proven by successfully complementing cytochrome-deficient Escherichia coli strain ECOM4. We conclude that A. muciniphila can use oxygen when it is present at nanomolar concentrations.

    Functional Profiling of Unfamiliar Microbial Communities Using a Validated De Novo Assembly Metatranscriptome Pipeline
    Davids, M. ; Hugenholtz, F. ; Martins dos Santos, V.A.P. ; Smidt, H. ; Kleerebezem, M. ; Schaap, P.J. - \ 2016
    PLoS ONE 11 (2016)1. - ISSN 1932-6203 - 18 p.
    BACKGROUND:
    Metatranscriptomic landscapes can provide insights in functional relationships within natural microbial communities. Analysis of complex metatranscriptome datasets of these communities poses a considerable bioinformatic challenge since they are non-restricted with a varying number of participating strains and species. For RNA-Seq data a standard approach is to align the generated reads to a set of closely related reference genomes. This only works well for microbial communities for which a near complete catalogue of reference genomes is available at a small evolutionary distance. In this study, we focus on the design of a validated de novo metatranscriptome assembly pipeline for single-end Illumina RNA-Seq data to obtain functional and taxonomic profiles of murine microbial communities.

    RESULTS:
    The here developed de novo assembly metatranscriptome pipeline combined rRNA removal, IDBA-UD assembler, functional annotation and taxonomic classification. Different assemblers were tested and validated using RNA-Seq data from an in silico generated mock community and in vivo RNA-Seq data from a restricted microbial community taken from a mouse model colonized with Altered Schaedler Flora (ASF). Precision and recall of resulting gene expression, functional and taxonomic profiles were compared to those obtained with a standard alignment method. The validated pipeline was subsequently used to generate expression profiles from non-restricted cecal communities of four C57BL/6J mice fed on a high-fat high-protein diet spiked with an RNA-Seq data set from a well-characterized human sample. The spike in control was used to estimate precision and recall at assembly, functional and taxonomic level of non-restricted communities.

    CONCLUSIONS:
    A generic de novo assembly pipeline for metatranscriptome data analysis was designed for microbial ecosystems, which can be applied for microbial metatranscriptome analysis in any chosen niche
    Urban Landscape Transitions: Analyzing Urban Agriculture Initiatives in Four European Cities
    Davids, P.R. ; Olde, E.M. de - \ 2014
    Identity Through Food: Food Sensitive Planning in the Municipality of Ridderkerk
    Olde, E.M. de; Davids, P.R. - \ 2014
    A comprehensive metatranscriptome analysis pipeline and its validation using human small intestine microbiota datasets
    Leimena, M.M. ; Ramiro-Garcia, J. ; Davids, M. ; Bogert, B. van den; Smidt, H. ; Smid, E.J. ; Boekhorst, J. te; Zoetendal, E.G. ; Schaap, P.J. ; Kleerebezem, M. - \ 2013
    BMC Genomics 14 (2013). - ISSN 1471-2164 - 14 p.
    ribosomal-rna - gene-expression - bacteria - seq - transcriptomes - diversity - quality - metagenomics - communities - identities
    Background: Next generation sequencing (NGS) technologies can be applied in complex microbial ecosystems for metatranscriptome analysis by employing direct cDNA sequencing, which is known as RNA sequencing (RNA-seq). RNA-seq generates large datasets of great complexity, the comprehensive interpretation of which requires a reliable bioinformatic pipeline. In this study, we focus on the development of such a metatranscriptome pipeline, which we validate using Illumina RNA-seq datasets derived from the small intestine microbiota of two individuals with an ileostomy. Results: The metatranscriptome pipeline developed here enabled effective removal of rRNA derived sequences, followed by confident assignment of the predicted function and taxonomic origin of the mRNA reads. Phylogenetic analysis of the small intestine metatranscriptome datasets revealed a strong similarity with the community composition profiles obtained from 16S rDNA and rRNA pyrosequencing, indicating considerable congruency between community composition (rDNA), and the taxonomic distribution of overall (rRNA) and specific (mRNA) activity among its microbial members. Reproducibility of the metatranscriptome sequencing approach was established by independent duplicate experiments. In addition, comparison of metatranscriptome analysis employing single- or paired-end sequencing methods indicated that the latter approach does not provide improved functional or phylogenetic insights. Metatranscriptome functional-mapping allowed the analysis of global, and genus specific activity of the microbiota, and illustrated the potential of these approaches to unravel syntrophic interactions in microbial ecosystems. Conclusions: A reliable pipeline for metatransciptome data analysis was developed and evaluated using RNA-seq datasets obtained for the human small intestine microbiota. The set-up of the pipeline is very generic and can be applied for (bacterial) metatranscriptome analysis in any chosen niche.
    Genome Analysis and Physiological Comparison of Alicycliphilus denitrificans Strains BC and K601(T.)
    Oosterkamp, M.J. ; Veuskens, T. ; Talarico Saia, F. ; Weelink, S.A.B. ; Goodwin, L.A. ; Daligault, H.E. ; Bruce, D.C. ; Detter, J.C. ; Tapia, R. ; Han, C.S. ; Land, M. ; Hauser, L. ; Langenhoff, A.A.M. ; Gerritse, J. ; Berkel, W.J.H. van; Pieper, D.H. ; Junca, H. ; Smidt, H. ; Schraa, G. ; Davids, M. ; Schaap, P.J. ; Plugge, C.M. ; Stams, A.J.M. - \ 2013
    PLoS ONE 8 (2013)6. - ISSN 1932-6203
    periplasmic nitrate reductase - anaerobic benzene degradation - cytochrome-c-oxidase - aromatic-compounds - perchlorate reduction - chlorite dismutase - reducing bacteria - rna genes - 1st step - metabolism
    The genomes of the Betaproteobacteria Alicycliphilus denitrificans strains BC and K601(T) have been sequenced to get insight into the physiology of the two strains. Strain BC degrades benzene with chlorate as electron acceptor. The cyclohexanol-degrading denitrifying strain K601(T) is not able to use chlorate as electron acceptor, while strain BC cannot degrade cyclohexanol. The 16S rRNA sequences of strains BC and K601(T) are identical and the fatty acid methyl ester patterns of the strains are similar. Basic Local Alignment Search Tool (BLAST) analysis of predicted open reading frames of both strains showed most hits with Acidovorax sp. JS42, a bacterium that degrades nitro-aromatics. The genomes include strain-specific plasmids (pAlide201 in strain K601(T) and pAlide01 and pAlide02 in strain BC). Key genes of chlorate reduction in strain BC were located on a 120 kb megaplasmid (pAlide01), which was absent in strain K601(T). Genes involved in cyclohexanol degradation were only found in strain K601(T). Benzene and toluene are degraded via oxygenase-mediated pathways in both strains. Genes involved in the meta-cleavage pathway of catechol are present in the genomes of both strains. Strain BC also contains all genes of the ortho-cleavage pathway. The large number of mono- and dioxygenase genes in the genomes suggests that the two strains have a broader substrate range than known thus far
    Chickens on the roofs and parties in the greenhouse : Urban agriculture and the facilitation of spatial planning
    Davids, P.R. ; Olde, E.M. de - \ 2012
    Topos : periodiek over landschapsarchitectuur, ruimtelijke planning en sociaal-ruimtelijke analyse 22 (2012). - ISSN 1572-302X - p. 34 - 37.
    Alle ballen op Wageningen
    Wageningen UR Centre for Development Innovation (CDI), - \ 2011
    food security - food production - universities
    Luminescence dating of Netherland's sediments
    Wallinga, J. ; Davids, F. ; Dijkmans, J.W.A. - \ 2007
    Netherlands journal of geosciences 86 (2007)3. - ISSN 0016-7746 - p. 179 - 196.
    Feldspar - Luminescence dating - OSL - Quartz - Quaternary

    Over the last decades luminescence dating techniques have been developed that allow earth scientists to determine the time of deposition of sediments. In this contribution we revity: 1) the development of the methodology, 2) tests of the reliability of luminescence dating on Netherlands' sediments; and 3) geological applications of the method in the Netherlands. Our review shows that optically stimulated luminescence dating of quartz grains using the single aliquot regenerative dose method yields results in agreement with independent age control for deposits ranging in age from a few years up to 125 ka. Optical dating of quartz has successfully been applied to sediments from a wide range of depositional environments such as coastal dunes, cover sands, fluvial channel deposits, colluvial deposits and fimic soils. These results demonstrate that optical dating is a powerful tool to explore the natural archive of the Netherlands' subsurface.

    Mechanisatie en automatisering moeten laanboomteelt lonend houden
    Davids, H. ; Schreuder, R. - \ 2006
    De Boomkwekerij 2006 (2006)49. - ISSN 0923-2443 - p. 11 - 11.
    boomkwekerijen - straatbomen - boomteelt - mechanisatie - landbouwwerktuigen - automatisering - innovaties - forest nurseries - street trees - arboriculture - mechanization - farm machinery - automation - innovations
    Gespecialiseerde laanboombedrijven hebben steeds meer moeite om aan (voldoende gekwalificeerd) personeel te komen. Tegelijkertijd nemen de loonkosten toe. De oplossing voor deze problemen ligt op het gebied van mechanisatie en innovatie.
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