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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    Review: Rumen sensors: Data and interpretation for key rumen metabolic processes
    Dijkstra, J. ; Gastelen, S. Van; Dieho, K. ; Nichols, K. ; Bannink, A. - \ 2020
    Animal 14 (2020)S1. - ISSN 1751-7311 - p. S176 - S186.
    data analysis - diurnal variation - fermentation - ruminants

    Rumen sensors provide specific information to help understand rumen functioning in relation to health disorders and to assist in decision-making for farm management. This review focuses on the use of rumen sensors to measure ruminal pH and discusses variation in pH in both time and location, pH-associated disorders and data analysis methods to summarize and interpret rumen pH data. Discussion on the use of rumen sensors to measure redox potential as an indication of the fermentation processes is also included. Acids may accumulate and reduce ruminal pH if acid removal from the rumen and rumen buffering cannot keep pace with their production. The complexity of the factors involved, combined with the interactions between the rumen and the host that ultimately determine ruminal pH, results in large variation among animals in their pH response to dietary or other changes. Although ruminal pH and pH dynamics only partially explain the typical symptoms of acidosis, it remains a main indicator and may assist to optimize rumen function. Rumen pH sensors allow continuous monitoring of pH and of diurnal variation in pH in individual animals. Substantial drift of non-retrievable rumen pH sensors, and the difficulty to calibrate these sensors, limits their application. Significant within-day variation in ruminal pH is frequently observed, and large distinct differences in pH between locations in the rumen occur. The magnitude of pH differences between locations appears to be diet dependent. Universal application of fixed conversion factors to correct for absolute pH differences between locations should be avoided. Rumen sensors provide high-resolution kinetics of pH and a vast amount of data. Commonly reported pH characteristics include mean and minimum pH, but these do not properly reflect severity of pH depression. The area under the pH × time curve integrates both duration and extent of pH depression. The use of this characteristic, as well as summarizing parameters obtained from fitting equations to cumulative pH data, is recommended to identify pH variation in relation to acidosis. Some rumen sensors can also measure the redox potential. This measurement helps to understand rumen functioning, as the redox potential of rumen fluid directly reflects the microbial intracellular redox balance status and impacts fermentative activity of rumen microorganisms. Taken together, proper assessment and interpretation of data generated by rumen sensors requires consideration of their limitations under various conditions.

    MOLECULAR-CELL-D-16-01367 Swarts et al
    Swarts, D.C. - \ 2017
    DNA sequencing - data analysis - gel
    This data contains the raw imaging data and sequencing data of the manuscript "Autonomous generation and loading of DNA guides by bacterial Argonaute" written by Swarts, Szczepaniak, Sheng et al.
    PMR Monitoring Natuurcompensatie Voordelta-bodemdieren : datarapport campagne bodemschaaf 2015-multivariate analyse 2004-2013
    Craeymeersch, J.A. ; Perdon, J. ; Jol, J. ; Brummelhuis, E.B.M. ; Asch, M. van - \ 2017
    IJmuiden : IMARES Wageningen UR (IMARES rapport C073.16) - 37
    voordelta - bodemarthropoden - bodeminvertebraten - monitoring - gegevensanalyse - zeevisserij - voordelta - soil arthropods - soil invertebrates - monitoring - data analysis - marine fisheries
    Het voorliggende rapport beschrijft de gewijzigde opzet van de monitoring, alsook de eerste monitoring-resultaten d.m.v. een korte beschrijving van de dataset verkregen met de bodemschaaf (omdat de monsters met de box-corer uit 2015 niet tijdig verwerkt waren om in dit rapport opgenomen te worden). Verder wordt de aanvullende studie nader besproken, qua opzet en resultaten van de multivariate analyses.
    Retrospectieve analyse van standaard vastgelegde data in de vleeskuikenproductieketen
    Jong, I.C. de; Riel, J.W. van - \ 2017
    Wageningen : Wageningen UR Livestock Research (Livestock Research rapport 1013) - 32
    vleeskuikens - vleeskuikenproductie - pluimveehouderij - prestatiekenmerken - gegevens verzamelen - gegevensanalyse - nederland - dierenwelzijn - dierlijke productie - broilers - broiler production - poultry farming - performance traits - data collection - data analysis - netherlands - animal welfare - animal production
    Open data voor precisielandbouw in Nederland
    Dijk, C.J. van; Kempenaar, C. - \ 2016
    Wageningen : Wageningen University & Research (Wageningen Plant Research rapport 662) - 32
    gegevens verzamelen - gegevensanalyse - gegevensbeheer - precisielandbouw - nederland - data collection - data analysis - data management - precision agriculture - netherlands
    In Nederland is het aanbod van open data voor precisielandbouw toepassingen divers maar relatief beperkt. Het zijn vooral de nationale en lokale overheden en (semi-overheids) instellingen zoals KNMI, Kadaster, CBS, PDOK, PBL en kennisinstellingen die hun data vrij beschikbaar stellen voor gebruik door derden. Binnen het agrarisch bedrijfsleven is er weinig tot geen bereidheid is tot het delen van data. Dit is terug te voeren op de zorgen die leven met betrekking tot eigendomsrechten, compliance, kwaliteit, aansprakelijkheid, beveiliging en privacy. Deze terughoudendheid is een rem op de mogelijkheden om toepassingen voor precisielandbouw te ontwikkelen. Naast technische oplossingen op het gebied van data management, infrastructuur en interoperability is er een sterke behoefte aan ‘verdienmodellen’ waarbij partijen die gegevens aanleveren delen in de revenuen (benefit-sharing).
    Development and application of a 20K SNP array in potato
    Vos, Peter - \ 2016
    Wageningen University. Promotor(en): Richard Visser; Fred van Eeuwijk, co-promotor(en): Herman van Eck. - Wageningen : Wageningen University - ISBN 9789462579569 - 166
    solanum tuberosum - potatoes - genotypes - single nucleotide polymorphism - data analysis - plant breeding - linkage disequilibrium - genome analysis - tetraploidy - solanum tuberosum - aardappelen - genotypen - single nucleotide polymorphism - gegevensanalyse - plantenveredeling - verstoord koppelingsevenwicht - genoomanalyse - tetraploïdie

    In this thesis the results are described of investigations of various application of genome wide SNP (single nucleotide polymorphism) markers. The set of SNP markers was identified by GBS (genotyping by sequencing) strategy. The resulting dataset of 129,156 SNPs across 83 tetraploid varieties was used directly to map traits, but also as a basis for the development of a 20K SNP array in Potato (Solanum tuberosum L.). Subsequently this array, named SolSTW, was used to collect genotypic data from 569 potato genotypes. This dataset offered insight in the breeding history of potato, population structure, linkage disequilibrium (LD) and the potential of GWAS (genome wide association studies) in potato.

    In Chapter 2 we describe to development of the SolSTW 20K Infinium SNP array. One third of the SNPs on this array originate from the well-known SolCAP 8303 SNP array. The other SNPs are a subset from a targeted re-sequencing project of 83 tetraploid potato varieties. Because of the high SNP density in potato only a limited number of SNPs is suitable for assay development on a SNP array. An obvious outcome is that flanking SNPs contribute to assay failure, particularly for assays with SNPs located in introns. We used fitTetra software to cluster the distribution of captured signals of each marker into the expected five genotypic classes (nulliplex, simplex, duplex, triplex, quadruplex), resulting in a dataset with 14,530 SNP markers. Subsequently the genotypic data obtained with the SolSTW array was used to characterize a set of 569 potato varieties, advanced breeding clones and progenitors. This resulted in the identification of several footprints of potato breeding. Firstly SNPs were dated i.e. the year of market release of the first variety showing polymorphism for a SNP locus is an indication of the ancestry of a SNP. In such a way we identified SNPs with an ancestry tracing back to heirloom varieties, and SNPs (post-1945 SNPs) tracing back to wild species used in modern introgression breeding. Secondly, the changes in allele frequency were calculated over time. Most SNPs show a relative stable allele frequency over time, and very limited genetic variation is removed from the gene-pool of potato i.e genetic erosion is almost absent. Therefore we conclude that 100 years of breeding has not been able to get rid of non-beneficial genetic variation. Only a limited number of SNPs show a rapid increased in allele frequency, which can be explained by positive selection for disease resistance by breeders, or the more frequent use of several founders.

    Better understanding of the genome wide decay of Linkage Disequilibrium (LD) and population structure offers relevant knowledge to perform and interpret the results of a genome wide association study (GWAS) (Chapter 3). Linkage disequilibrium (LD) is a complex phenomenon, and the influence of the factors shaping LD in tetraploids is hardly studied. Therefore we used simulated data to disentangle and therewith understand often-confounded factors underlying LD-decay. We simulated datasets differing in number of haplotypes in a population, and differing in percentage of haplotype specific SNPs. In these simulations we observed that the choice of an estimator of LD-decay has a major effect on the outcome of an LD-decay estimate, while the true LD-decay remains the same. Based on the simulation we conclude that a 90% percentile and a so-called D1/2 (the distance where 50% of the initial LD is decayed) performed best to estimate and compare LD-decay in potato. To understand the various aspects of LD-decay in the variety panel of 537 varieties, the panel was subdivided in several groups based on the age of a variety and the population structure groups. This resulted in the identification of LD-decay over time, i.e in relatively young varieties the average size of the LD-blocks is smaller. The differences between subpopulations were smaller and are most likely the effect of the population structure. We also observed that there are very long LD-blocks caused by introgression breeding and that different a priori MAF-thresholds also can influence the outcome of LD-decay estimation.

    Having both LD-decay and population structure defined a genome wide association study (GWAS) was conducted (Chapter 4). For this purpose α-solanine and α-chaconine were measured in potato tubers. Subsequently the sum of both (total SGA) and the ratio between the two were used to discover QTLs for these traits in a GWAS. Additionally we used three bi-parental populations to validate the GWAS results. Total SGA content was confounded with population structure and therefore it was difficult to explain all phenotypic variation with SNP markers. Two QTLs (Sgt1.1 and Sgt11.1) were identified which could be validated in one of the segregating populations. The ratio between α-solanine and α-chaconine was not confounded with population structure, resulted in the identification of two major-effect QTLs (Sgr7.1 & Sgr8.1) located near the candidate genes SGT1 and SGT2, which are known for being responsible in the final steps towards either α-solanine or α-chaconine. The QTL Sgr8.1 could be validated, however similar phenotypes were explained by different haplotypes in two populations. We show that population structure, low frequent alleles and genetic heterogeneity may explain to some degree the missing heritability in GWAS in potato.

    In Chapter 5 we describe how the method of graphical genotyping, which is widely used in diploid bi-parental populations, can be applied in a variety panel of tetraploid varieties. We show that a few discrete filtering steps in Excel can be used to display patterns that are visual representations of introgression segments and the locations of historical recombination events. Using this method we identified introgression segments from Solanum vernei including the Gpa5 locus on chromosome 5 and Solanum stoloniferum introgression segment including a gene involved in resistance to Potato Virus Y on chromosome 11. This method requires that the haplotypes that cause the phenotypic effect have to be identical by descent (IBD).

    In the final chapter 6 the results of chapter 2 to 5 are discussed. We look forward on how our results can be used in future research and applied in marker-assisted breeding. Additionally some new GWAS results are presented for tuber flesh colour, foliage maturity and resistance to Globodera pallida pathotype 3.

    Waardekaarten Markham’s Triangle & Hornsea 3
    Machiels, Marcel - \ 2016
    Wageningen : Wageningen Marine Research (Wageningen Marine Research rapport C085/16) - 15
    visserij - waarden - tabellen - gegevensanalyse - fisheries - values - tables - data analysis
    Big data analysis for smart farming : Results of TO2 project in theme food security
    Kempenaar, C. ; Lokhorst, C. ; Bleumer, E.J.B. ; Veerkamp, R.F. ; Been, Th. ; Evert, F.K. van; Boogaardt, M.J. ; Ge, L. ; Wolfert, J. ; Verdouw, C.N. ; Bekkum, Michael van; Feldbrugge, L. ; Verhoosel, Jack P.C. ; Waaij, B.D. ; Persie, M. van; Noorbergen, H. - \ 2016
    Wageningen : Wageningen University & Research (Wageningen Plant Research report ) - 82
    animal production - milk production - farming - data analysis - data collection - information technology - models - dierlijke productie - melkproductie - landbouw bedrijven - gegevensanalyse - gegevens verzamelen - informatietechnologie - modellen
    In this report we describe results of a one-year TO2 institutes project on the development of big data technologies within the milk production chain. The goal of this project is to ‘create’ an integration platform for big data analysis for smart farming and to develop a show case. This includes both technical (hard/software) and organizational integration (developing business ecosystem) and combining and linking of data and models. DLO, NLR and TNO worked together in 2015 towards the realization of an IT data infrastructure that makes it possible to solve to connect data from different sources and models in an effective and safe way, ontology problems, specific analysis tools develop, opportunities and risks to identify and assess the acquired knowledge and experience and present it in a smart farming show case, from 'grass to glass‘.
    Host-plant resistance to western flower thrips in Arabidopsis
    Thoen, Manus P.M. - \ 2016
    Wageningen University. Promotor(en): Marcel Dicke; Harro Bouwmeester, co-promotor(en): Maarten Jongsma. - Wageningen : Wageningen University - ISBN 9789462578807 - 191
    arabidopsis thaliana - host plants - insect pests - frankliniella occidentalis - defence mechanisms - pest resistance - genomics - genome analysis - host-seeking behaviour - optical tracking - data analysis - insect plant relations - arabidopsis thaliana - waardplanten - insectenplagen - frankliniella occidentalis - verdedigingsmechanismen - plaagresistentie - genomica - genoomanalyse - gedrag bij zoeken van een gastheer - optisch sporen - gegevensanalyse - insect-plant relaties

    Western flower thrips is a pest on a large variety of vegetable, fruit and ornamental crops. The damage these minute slender insects cause in agriculture through feeding and the transmission of tospoviruses requires a sustainable solution. Host-plant resistance is a cornerstone of Integrated Pest Management (IPM). Plants have many natural defense compounds and morphological features that aid in the protection against herbivorous insects. However, the molecular and physiological aspects that control host-plant resistance to thrips are largely unknown.

    A novel and powerful tool to study host-plant resistance to insects in natural populations is genome-wide association (GWA) mapping. GWA mapping provides a comprehensive untargeted approach to explore the whole array of plant defense mechanisms. The development of high-throughput phenotyping (HTP) systems is a necessity when large plant panels need to be screened for host-plant resistance to insects. An automated video-tracking platform that could screen large plant panels for host-plant resistance to thrips, and dissect host-plant resistance to thrips in component traits related to thrips behavior, was developed. This phenotyping platform allows the screening for host-plant resistance against thrips in a parallel two-choice setup using EthoVision tracking software. The platform was used to establish host-plant preference of thrips with a large plant population of 345 wild Arabidopsis accessions (the Arabidopsis HapMap population) and the method was optimized with two extreme accessions from this population that differed in resistance to thrips. This method can be a reliable and effective high throughput phenotyping tool to assess host-plant resistance to thrips in large plant populations. EthoAnalysis, a novel software package was developed to improve the analyses of insect behavior. There were several benefits from using EthoAnalysis to analyze EthoVision data. The detailed event statistics that could be extracted from EthoAnalysis allows researchers to distinguish detailed differences in moving and feeding behavior of thrips. The potential of this additional information is discussed in the light of quantitative genetic studies.

    Stress resistance was studied in the HapMap population on a total of 15 different biotic and abiotic stresses ranging from biotic stresses like insects and nematodes, to abiotic stresses like drought and salt. A multi-trait GWA study to unravel the genetic architecture underlying plant responses to the different stresses was performed. A genetic network in this study revealed little correlation between the plant responses to the different insect herbivores studied (aphids, whiteflies, thrips and caterpillars). For thrips resistance a weak positive correlation with resistance to drought stress and Botrytis, and a negative correlation with resistance to parasitic plants were observed. One of the surprising outcomes of this study was the absence of shared major QTLs for host-plant resistance and abiotic stress tolerance mechanisms. RESISTANCE METHYLATED GENE 1 (RMG1) was one of the candidate genes in this multi-trait GWA study that could be controlling shared resistance mechanisms against many different stresses in Arabidopsis. RMG1 is a nucleotide-binding site Leucine-rich repeat (NB-LRR) disease resistance protein and its potential relation to several resistance/tolerance traits was successfully demonstrated with T-DNA insertion lines.

    The 15 stresses were used in a comparison with a metabolomics dataset on this Arabidopsis HapMap population. It was discovered that levels of certain aliphatic glucosinolates correlated positively with the levels of resistance to thrips. This correlation was further investigated with the screening of a RIL (Recombinant Inbred Line) population for resistance to thrips, several knockout mutants and the analysis of co-localization of GWA mapping results between glucosinolates genes and thrips resistance. In a GWA analysis, the C4 alkenyl glucosinolates that correlated the strongest with thrips resistance mapped to the genomic regions containing genes known to regulate the biosynthesis of these compounds. However, thrips resistance did not co-localize with any of the GSL genes, unless a correction for population stratification was omitted. Additional screening of a Cvi x Ler RIL population showed a QTL for thrips resistance on chromosome 2, but no co-localization with any known glucosinolate genes, nor with thrips resistance loci identified by GWA mapping. Knock-out mutants and overexpressors of glucosinolate synthesis genes could also not confirm a causal link between glucosinolates and resistance to thrips. It is possible that the crucial factors that control resistance to thrips may not have been present in sufficient quantities or in the right combinations in the mutants, RILs and NIL screened in this study. Alternatively, the correlation between thrips feeding damage and glucosinolate profiles could be based on independent geographical clines. More research should be conducted to assess which of these explanations is correct.

    In the general discussion, the results from this thesis are discussed in a broader perspective. Some prototypes of new phenotyping platforms that could further aid screening for resistance to thrips in the future are presented. Natural variation in host-plant resistance to thrips is compared to the variation in host-plant resistance to aphids and caterpillars. The geographic distribution of host-plant resistance to thrips is not evident in the other insects, in line with the distribution of glucosinolate profiles and other climate factors. The chapter concludes with some suggestions for future research in the field of host-plant resistance to thrips.

    Invloed van beekbegeleidende bomen op de ecologische kwaliteit van Noord-Brabantse beken
    Verdonschot, R.C.M. ; Brugmans, Bart ; Scheepens, Mark ; Coenen, Daniël ; Verdonschot, P.F.M. - \ 2016
    H2O online (2016)28 juli.
    aquatische ecologie - waterlopen - bomen - noord-brabant - monitoring - beschaduwen - gegevensanalyse - waterschappen - vegetatie - waterplanten - waterkwaliteit - aquatic ecology - streams - trees - noord-brabant - monitoring - shading - data analysis - polder boards - vegetation - aquatic plants - water quality
    Monitoringsdata van Brabantse beken laat zien dat bomen belangrijk zijn voor het halen van ecologische doelen. Echter, voor maximale effectiviteit met betrekking tot vegetatieontwikkeling en koeling van het beekwater voldoet alleen de zwaarste beschaduwingsklasse (>70%) en moet gestreefd worden naar lange beschaduwde trajecten. Macrofauna profiteert vooral via de door bomen gegenereerde substraatdifferentiatie. Het toepassen van beschaduwing brengt voor de waterschappen wel grote uitdagingen met zich mee. Verder blijkt uit de data-analyse dat jaarrond voldoende stroming een vereiste is voor de ecologische doelrealisatie in de trajecten.
    Meerwaarde van ruimtelijke neerslagdata voor het modelleren van stijghoogtefluctuaties
    Ottow, Bouke Pieter ; Schuurmans, H. ; Steijn, T. van - \ 2015
    Stromingen : vakblad voor hydrologen 24 (2015)4. - ISSN 1382-6069 - p. 43 - 52.
    grondwaterstand - watersystemen - neerslag - grondwater - hydrologie - tijdreeksen - gegevensanalyse - grondwateraanvulling - groundwater level - water systems - precipitation - groundwater - hydrology - time series - data analysis - groundwater recharge
    Om het effect van velerlei processen die van invloed zijn op grondwaterstanden goed te kunnen analyseren, is het belangrijk om goed te weten wat de respons van het grondwatersysteem is op de neerslag. Een methode om dat te modelleren is de PIRFICT tijdreeksanalyse geïmplementeerd in het programma Menyanthes. De meest gebruikte databron voor neerslag is de neerslagstations van het KNMI. Waar de neerslagstations soms 5 à 10 km van een peilbuis af staan, zorgen radargebaseerde neerslagproducten voor vlakdekkende informatie. Hiermee wordt een nauwkeuriger beeld van de lokale neerslag verkregen. De invloed van dit verschil op een tijdreeksanalysemodel is onderzocht voor 77 locaties met 109 peilbuisfilters in de Mariapeel (Noord-Brabant/Limburg). De gemiddelde verklaarde variantie van de modellen ging door gebruik van de Nationale Regenradar omhoog van 69,1% naar 76,9%. Het resultaat van deze case studie geeft aan dat het opportuun is om ook elders ruimtelijke informatie van neerslag te gebruiken voor grondwaterstudies.
    Plan van Aanpak voor MBO 'training en opleiding' rond Smart Dairy Farming : onderdeel van BOGO project 'Sensoren in SDF 1.0: lessen voor validatie en informatievoorziening'
    Lokhorst, C. ; Fokkema, R. - \ 2015
    Livestock Research Wageningen UR (Livestock Research rapport 934) - 14
    melkveehouderij - gegevens verzamelen - gegevensanalyse - sensors - bedrijfsvoering - opleiding melkveehouderij - beroepsopleiding - onderwijsprogramma's - dairy farming - data collection - data analysis - sensors - management - dairy education - vocational training - education programmes
    Boomkronen afleiden uit het Actueel Hoogtebestand Nederland : kwaliteitsaspecten rondom het geautomatiseerd in kaart brengen van bomen op basis van het AHN2-bestand
    Meijer, M. ; Rip, Frans ; Benthem, R. van; Clement, J. ; Sande, C. van der - \ 2015
    Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2671) - 85
    bomen - kroondak - kroon - gegevensanalyse - gegevens verzamelen - methodologie - remote sensing - hoogteligging - cartografie - nederland - trees - canopy - crown - data analysis - data collection - methodology - remote sensing - altitude - mapping - netherlands
    Alom wordt erkend dat bomen belangrijk zijn. Zowel voor de mens, de natuur als het klimaat. Recentelijk is een procedure ontwikkeld om op basis van het nationale Nederlandse hoogtebestand AHN2 een bestand te genereren met alle boomkronen in Nederland, genaamd ‘CP’. Een dergelijk bestand kan onder andere het groenbeheer van de gemeenten in Nederland vereenvoudigen en helpen bij het inventariseren van landschapselementen. De vraag is echter: hoe goed is dit bestand? In dit rapport wordt voor een drietal verschillende gebieden onderzocht wat de kwaliteit is van CP. Verder wordt mede op basis van de ervaringen die tijdens het kwaliteitsonderzoek zijn gedaan een standaard kwaliteitsraamwerk opgezet voor het controleren van nieuwe versies van het boomkronenbestand. Daarnaast is dit document er ook op gericht om de potentiële gebruiker een beter beeld van de kwaliteit te geven.
    Robustness of life cycle assessment results : influence of data variation and modelling choices on results for beverage packaging materials
    Harst-Wintraecken, E.J.M. van der - \ 2015
    Wageningen University. Promotor(en): Carolien Kroeze, co-promotor(en): Jose Potting. - Wageningen : Wageningen University - ISBN 9789462575097 - 217
    levenscyclusanalyse - onzekerheid - modelleren - gegevensanalyse - gegevens verzamelen - afvalverwerking - recycling - milieueffect - life cycle assessment - uncertainty - modeling - data analysis - data collection - waste treatment - recycling - environmental impact

    Life cycle assessment (LCA) is a well-established method to evaluate the potential environmental impacts of product and service systems throughout their life cycles. However, it can happen that LCAs for the same product have different and even conflicting outcomes. LCA results need to be robust and trustworthy if they are used in decision making. The aim of this thesis is to evaluate whether the use of multiple data sets and multiple modelling options can increase the robustness of LCA results.

    The research starts with identifying reasons for differences in LCA results for the same product. The results of ten existing LCAs for disposable beverage cups are compared to each other as to examine the consistency and robustness of these results. The comparison of the LCAs shows no consistent best or worst cup material. And, the quantitative results for cups made from the same material vary across the LCAs. The evaluation of the methodological choices and the used data sources in each LCA made it possible to identify possible sources for discrepancies in the LCA results. Reasons for differences in results include the variation in the properties of the cups, production processes, waste treatment options, allocation options, choices in system boundaries, impact indicators, and potentially also the data sets that are used.

    The thesis next describes a novel method to evaluate and include the influence of data sets and modelling choices on the LCA results. The method is applied in a case study of a disposable polystyrene (PS) beverage cup. The study purposely uses different data sets from various sources for processes with an influential contribution to the LCA results. The study includes two waste treatment options (incineration and recycling). The multiple data sets represent the variability among processes, and the waste treatments represent choices in the modelling of the life cycle of the PS cup.

    This variability among the data sets for a similar process is presented as a spread in the results. This spread in the results for the PS cup is caused by differences in the amount and type of the used resources and energy, reported emissions, the origin of the production location, the time period of data collection, or choices in the value of recycled PS. The overlapping spread in the quantitative results for incineration and recycling prevents a decisive conclusion on the preferred waste treatment option for the PS cups.

    Next, the method for the use of multiple data sets and modelling choices is applied in a comparative LCA of disposable beverage cups. Three cups are compared: a PS cup, a polylactic acid cup (PLA, a biobased plastic), and a cup made from biopaper (paper with a lining of biobased-plastic). The waste treatment options consist of incineration and recycling for all three cups, and additionally composting and anaerobic digestion for the PLA and biopaper cup.

    The use of multiple data sets and modelling choices leads to a considerable spread in the LCA results of the cups. The results do not point to the most environmentally friendly cup material, and neither to a preferred waste treatment option. The results clearly identify composting, however, as the least preferred waste treatment option for the PLA and biopaper cups. The spread in the results makes the comparison of the results for the cups more complex, but the results provides more robust information for decision makers. The combined inclusion of the variability among data sets and the waste treatment options makes the results more trustworthy.

    The thesis then dives deeper into the methodological modelling of recycling in LCA and describes and evaluates six widely used recycling modelling methods: three substitution methods, an allocation method, the recycled-content method, and the equal-share method. The main difference among the six methods lies in the assumption on where and how to apply credits for recycled material in the life cycle of the product.

    These six methods are applied in two case studies: a disposable PS beverage cup and an aluminium beverage can. The results for the aluminium can clearly depend on the applied recycling modelling method, the recycling rate of the disposed cans, and the amount of recycled material used in the cans. The results for the PS cup additionally depend on the consideration of a drop in the quality of the recycled PS compared to the original PS, and the other waste treatments (landfilling and incineration) for the cups. Including several recycling modelling methods in the LCA incorporates the various underlying modelling philosophies of the methods, and thus makes the results more robust.

    This thesis demonstrates the added value of including multiple data sets and multiple modelling choices in LCA. The use of multiple data sets is especially useful if general processes instead of specific processes are used in the representation of the product system. The use of multiple data sets increases the accuracy of the results, and is a supplemental tool next to statistical methods which increase the precision of the results. The simultaneous handling of variability among data sets and modelling choices is hardly performed in LCA. The method presented in this thesis fills this gap and provides a transparent tool to capture these uncertainties. The trade-off between an increase in the robustness of the results and the additional demand for resources (time, money, effort) should be assessed, and depends on the goal of the study and on the intended use of the results. This thesis shows that inclusion of the uncertainty in the LCA results provides the decision maker with valuable information. This thesis thus provides a useful method to increase the robustness of LCA results.

    Systematische fouten in metingen van grondwaterstanden met drukopnemers : verslag van een data-analyse
    Pleijter, M. ; Hamersveld, L. ; Knotters, M. - \ 2015
    Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2666) - 23
    grondwaterstand - grondwater - fouten - meting - gegevensanalyse - groundwater level - groundwater - errors - measurement - data analysis
    Handmetingen zijn onmisbaar bij het gebruik van automatische grondwaterstandopnemers om meetfouten te kunnen opsporen. Wij onderzochten de verschillen tussen handmetingen van de grondwaterstand en metingen uitgevoerd met drukopnemers. Hierbij analyseerden we van 474 locaties meetreeksen van ca. twee jaar lang. We keken of de opgetreden verschillen systematisch zijn en of er trends te ontdekken zijn die duiden op drift van het nulpunt van de drukopnemers. Bij 144 locaties (30%) is een significante lineaire toename van de verschilwaarden aangetoond, die zowel positief als negatief kan zijn. Een algemeen verloop van de verschilwaarden kon niet worden aangetoond. Voor metingen van individuele drukopnemers bevelen we aan om, als de verschillen binnen twee jaar oplopen tot meer dan 2 cm, de metingen van de drukopnemer met behulp van een lineair regressiemodel aan te passen aan de handmetingen. We bevelen aan om ten minste vier handmetingen per jaar te verrichten en om eenmaal per twee jaar een eventuele correctie uit te voeren. Deze handmeting moet in het veld worden gecontroleerd met de gecompenseerde meting van de drukopnemer. Hierdoor wordt de kans op het maken van een fout in de handmeting verkleind.
    Waardekaarten Sylter Aussenriff
    Machiels, M.A.M. - \ 2015
    IJmuiden : IMARES (Rapport / IMARES Wageningen UR C129/15) - 11
    visserij - waarden - tabellen - boomkorvisserij - gegevensanalyse - fisheries - values - tables - beam trawling - data analysis
    Dit rapport is geschreven in opdracht van VisNed. IMARES is gevraagd om waardekaarten en tabellen te leveren van alle bodem beroerende Nederlandse visserijschepen binnen het gebied Sylter Außenriff.
    Joined spray drift curves for boom sprayers in The Netherlands and Germany
    Zande, J.C. van de; Rautmann, D. ; Holterman, H.J. ; Huijsmans, J.F.M. - \ 2015
    Wageningen : Plant Research International, Business Unit Agrosystems (Report / Plant Research International 526) - 82
    gewasbescherming - eu regelingen - nederland - duitsland - landbouwwerktuigen - spuitapparatuur - bodemoppervlakbespuiting - spuitstukken - gegevensanalyse - drift - plant protection - eu regulations - netherlands - germany - farm machinery - spraying equipment - ground surface spraying - nozzles - data analysis - drift
    This report gives a summary of the outcome of the analyses of the spray drift data for boom sprayers from Germany and The Netherlands.
    Overview of topics and questions to be addressed by the FG Mainstreaming Precision Farming : starting paper for FG meeting held on 3 and 4 June 2014
    Kempenaar, C. - \ 2014
    Brussels : EIP-AGRI - 9
    precisielandbouw - akkerbouw - voedselketens - agro-industriële ketens - software-ontwikkeling - gegevensanalyse - gegevensverwerking - akkerbouw- en tuinbouwbedrijven - veehouderijbedrijven - precision agriculture - arable farming - food chains - agro-industrial chains - software engineering - data analysis - data processing - crop enterprises - livestock enterprises
    Precision farming is an innovation in agriculture allowing the right treatment of crops and livestock at the right time and smallest scale possible. It requires a seamless integration of different technologies and intelligence. Optimization of treatments at the lowest scale possible will improve yields and resource efficiency in agri-food chains, so reducing the agricultural footprint. More and more, precision farming will become the ‘licence to produce’ for farmers in the EU.
    State of the art in federated querying in SPARQL
    Wigham, M.L.I. - \ 2014
    Wageningen : Wageningen UR (Rapport / Wageningen UR Food & Biobased Research nr. 1522) - 13
    gegevens verzamelen - gegevensanalyse - voedsel - data collection - data analysis - food
    Semantic support for data analysis
    Boer, E.P.J. ; Willems, D.J.M. ; Top, J.L. - \ 2014
    Wageningen : Wageningen UR (Rapport / Wageningen UR Food & Biobased Research nr. 1524) - 14
    gegevensanalyse - voedsel - data analysis - food
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