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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    Programma van Eisen van de leghen 2020 : Ontwerpen voor een goed dierenwelzijn
    Weeghel, Ellen van; Jong, Ingrid de; Niekerk, Thea van; Bos, Bram - \ 2020
    Wageningen : Wageningen Livestock Research (Rapport / Wageningen Livestock Research 1263) - 60
    In a so-called Brief of Requirements an overview of the needs of laying hens and the requirements that the animals pose on their living conditions are given. This report addresses the in-depth literature study and the instructions for use. In the BoR of the laying hen 2020 the conditions for positive welfare are included for the first time. The BoR is a design tool to acknowledge and include the animal as an actor in the design process. The overview of needs and the derived requirements for which a poultry system has to comply make it possible to design for good animal welfare, in addition, the conditions for positive welfare promote opportunities for the animals to have positive emotions and experiences.
    Sparse regression interaction models for spatial prediction of soil properties in 3D
    Pejović, Milutin ; Nikolić, Mladen ; Heuvelink, Gerard B.M. ; Hengl, Tomislav ; Kilibarda, Milan ; Bajat, Branislav - \ 2018
    Computers and Geosciences 118 (2018). - ISSN 0098-3004 - p. 1 - 13.
    3D - Interactions - Lasso - Nested cross-validation - Soil organic carbon - Spatial prediction

    An approach for using lasso (Least Absolute Shrinkage and Selection Operator) regression in creating sparse 3D models of soil properties for spatial prediction at multiple depths is presented. Modeling soil properties in 3D benefits from interactions of spatial predictors with soil depth and its polynomial expansion, which yields a large number of model variables (and corresponding model parameters). Lasso is able to perform variable selection, hence reducing the number of model parameters and making the model more easily interpretable. This also prevents overfitting, which makes the model more accurate. The presented approach was tested using four variable selection approaches – none, stepwise, lasso and hierarchical lasso, on four kinds of models – standard linear model, linear model with polynomial expansion of depth, linear model with interactions of covariates with depth and linear model with interactions of covariates with depth and its polynomial expansion. This framework was used to predict Soil Organic Carbon (SOC) in three contrasting study areas: Bor (Serbia), Edgeroi (Australia) and the Netherlands. Results show that lasso yields substantial improvements in accuracy over standard and stepwise regression — up to 50 % of total variance. It yields models which contain up to five times less nonzero parameters than the full models and that are usually more sparse than models obtained by stepwise regression, up to three times. Extension of the standard linear model by including interactions typically improves the accuracy of models produced by lasso, but is detrimental to standard and stepwise regression. Regarding computation time, it was demonstrated that lasso is several orders of magnitude more efficient than stepwise regression for models with tens or hundreds of variables (including interactions). Proper model evaluation is emphasized. Considering the fact that lasso requires meta-parameter tuning, standard cross-validation does not suffice for adequate model evaluation, hence a nested cross-validation was employed. The presented approach is implemented as publicly available sparsereg3D R package.

    Validation of a screening method for pesticides and veterinary drug residues in feed by LC-HRMS
    Wegh, R.S. ; Bolck, Y.J.C. ; Bor, G. ; Zomer, P. ; Zuidema, T. ; Mol, J.G.J. - \ 2018
    Study of the aminoglycoside subsistence phenotype of bacteria residing in the gut of humans and zoo animals
    Bello Gonzalez, Teresita ; Zuidema, Tina ; Bor, Gerrit ; Smidt, Hauke ; Passel, M.W.J. van - \ 2016
    Frontiers in Microbiology 6 (2016)JAN. - ISSN 1664-302X - 7 p.
    Aminoglycosides - Antibiotic resistance - Antibiotic subsistence - Antibiotic subsistence phenotype - Single carbon source

    Recent studies indicate that next to antibiotic resistance, bacteria are able to subsist on antibiotics as a carbon source. Here we evaluated the potential of gut bacteria from healthy human volunteers and zoo animals to subsist on antibiotics. Nine gut isolates of Escherichia coli and Cellulosimicrobium sp. displayed increases in colony forming units (CFU) during incubations in minimal medium with only antibiotics added, i.e., the antibiotic subsistence phenotype. Furthermore, laboratory strains of E. coli and Pseudomonas putida equipped with the aminoglycoside 3' phosphotransferase II gene also displayed the subsistence phenotype on aminoglycosides. In order to address which endogenous genes could be involved in these subsistence phenotypes, the broad-range glycosyl-hydrolase inhibiting iminosugar deoxynojirimycin (DNJ) was used. Addition of DNJ to minimal medium containing glucose showed initial growth retardation of resistant E. coli, which was rapidly recovered to normal growth. In contrast, addition of DNJ to minimal medium containing kanamycin arrested resistant E. coli growth, suggesting that glycosyl-hydrolases were involved in the subsistence phenotype. However, antibiotic degradation experiments showed no reduction in kanamycin, even though the number of CFUs increased. Although antibiotic subsistence phenotypes are readily observed in bacterial species, and are even found in susceptible laboratory strains carrying standard resistance genes, we conclude there is a discrepancy between the observed antibiotic subsistence phenotype and actual antibiotic degradation. Based on these results we can hypothesize that aminoglycoside modifying enzymes might first inactivate the antibiotic (i.e., by acetylation of amino groups, modification of hydroxyl groups by adenylation and phosphorylation respectively), before the subsequent action of catabolic enzymes. Even though we do not dispute that antibiotics could be used as a single carbon source, our observations show that antibiotic subsistence should be carefully examined with precise degradation studies, and that its mechanistic basis remains inconclusive.

    Properties of anthropogenic soils in ancient run-off capturing agricultural terraces in the Central Negev desert (Israel) and related effects of biochar and ash on crop growth
    Asperen, H.L. van; Bor, A.M.C. ; Sonneveld, M.P.W. ; Bruins, H.J. ; Lazarovitch, N. - \ 2014
    Plant and Soil 374 (2014)1-2. - ISSN 0032-079X - p. 779 - 792.
    charcoal - productivity - manure - model
    In the Central Negev hills (Israel) many ancient terraced wadis exist, which captured run-off and caused gradual soil aggradation, which enabled agricultural practices. In these terraces, dark colored soil horizons were observed, containing charcoal, as can be found in Terra Preta soils, suggesting higher fertility compared to natural soils. The aim of our investigation was to investigate these anthropogenic soils and to study the effects of charcoal and ash addition on soil properties and crop growth. We investigated 12 soil profiles, focusing on possible differences between light and dark colored soil horizons. We also investigated the effects of amendment of charcoal and ash on the growth of wheat (Triticum Aestivum L.) in a 40-day pot experiment involving two water regimes. Results show that charcoal content in light and dark horizons were both low (<0.2 %), but significantly lower bulk densities were found in dark colored horizons. In the crop experiment, charcoal addition resulted in decreased crop growth, while, in the water deficit regime, ash addition resulted in increased crop growth. Considering the observed charcoal and the results from the crop experiment, we hypothesize that, in ancient run-off capturing agricultural systems, ash was purposefully added as fertilizer.
    Bleaching of the post-IR IRSL signal: new insights for feldspar luminescence dating
    Kars, R.H. ; Reimann, T. ; Ankjaergaard, C. ; Wallinga, J. - \ 2014
    Boreas 43 (2014)4. - ISSN 0300-9483 - p. 780 - 791.
    anomalous fading correction - stimulated luminescence - k-feldspar - sediment extracts - young sediments - chinese loess - quartz - osl - protocol - thermoluminescence
    Post-infrared (pIR) stimulated luminescence dating of sedimentary feldspar largely avoids the effects of anomalous fading that affect conventional infrared stimulated luminescence (IRSL) dating. However, optical resetting of pIR signals is more difficult than resetting the conventional IRSL signal, which may undermine the crucial assumption that pIR signals were effectively bleached upon deposition and burial of sediment grains. In this study, we quantify the bleaching properties of several pIR signals on various samples using laboratory-simulated bleaching in full sunlight and water-attenuated sunlight. Our data show that bleaching is most efficient under full spectrum conditions for all pIR signals and that pIR signals measured at elevated temperature are increasingly harder to bleach than IR and pIR signals measured at low temperature (e.g. IR at 50°C). All bleaching curves exhibit a very slow and steady decrease, indicating that a fixed un-bleachable residual level cannot be reached within the 11 days of solar simulator exposure undertaken here. We show that the magnitude of a laboratory-determined residual dose depends on the adopted bleaching protocol and cannot be used as a proxy for the dose that remains in the sample at the time of burial (remnant dose). Our data emphasize the importance of finding a balance between sufficient signal stability and a minimized contribution of a remnant dose when using pIR procedures for feldspar luminescence dating.
    The disposition of oxytetracycline to feathers after poultry treatment
    Berendsen, B.J.A. ; Bor, G. ; Gerritsen, H.W. ; Jansen, L.J.M. ; Zuidema, T. - \ 2013
    Food Additives & Contaminants. Pt. A, Chemistry, Analysis, Control, Exposure & Risk Assessment 30 (2013)12. - ISSN 1944-0049 - p. 2102 - 2107.
    tandem mass-spectrometry - growth-promoting agents - residue analysis - veterinary drugs - bovine - feed
    In the combat against bacterial resistance, there is a clear need to check the use of antibiotics in animal husbandry, including poultry breeding. The use of chicken feathers as a tool for the detection of use of antibiotics was investigated. An extraction method for the analysis of oxytetracycline (OTC) from feathers was developed and was tested by using incurred feathers obtained from a controlled animal treatment study. The use of McIlvain-ethylenediaminetetraacetic acid buffer only in combination with acetone gave the highest extraction yield, indicating the need of an organic solvent for feather extraction. By using the developed method, it was found that after a withdrawal time, the OTC concentration in feathers is in the mg kg(-1) range, far higher than that in muscle and liver tissue. Based on the analysis of individual segments of feathers from OTC-treated chicken, evidence was found supporting the hypothesis of secretion of antibiotics through the uropygial gland and external spread over feathers by grooming behaviour. It was also found that part of the administered OTC is built into the feather rachis. Finally, we provide the first evidence that the analysis of individual segments of the rachis can be used as a tool to discriminate among different treatment strategies, for example, therapeutic versus subtherapeutic. As a result, we concluded that the analysis of feathers is an extremely valuable tool in residue analysis of antibiotics.
    Brief of requirements of the broiler = Programma van eisen van het vleeskuiken
    Hoeks, C. ; Bokkers, E.A.M. ; Bos, A.P. ; Jong, I.C. de; Janssen, A.P.H.M. ; Groot Koerkamp, P.W.G. - \ 2011
    Lelystad : Wageningen UR Livestock Research (Report / Wageningen UR Livestock Research 517) - 46
    pluimveehouderij - kuikenproductie - vleesproductie - groeitempo - dierenwelzijn - poultry farming - chick production - meat production - growth rate - animal welfare
    This report lists the brief of requirements of the broiler, based on her needs (also listed). The BoR indicates the actor’s needs with regards to the animal husbandry system. BoR of the main actors are incorporated in the redesign of a broiler husbandry system in the project Tasteful Broilers.
    Obese patienten met alledaagse kwalen. Vaker op consultatie bij de huisarts?
    Lemiengre, M.B.T. ; Wayenburg, C.A.M. van; Reenen-Schimmel, A.H. van; Bor, J.H.J. ; Bakx, J.C. ; Staveren, W.A. van; Weel, C. van; Binsbergen, J.J. van - \ 2009
    Huisarts NU 38 (2009)9. - ISSN 0775-0501 - p. 376 - 380.
    Obese patiënten komen vaker met alledaagse kwalen bij de huisarts, in het bijzonder verkoudheden (zonder koorts), spierpijn van de bovenste gordel, dermatofytosis en kneuzing (contusie, hematoom). Dit komt bovenop de al hogere prevalentie van chronische aandoeningen gerelateerd aan obesitas. Deze resultaten zijn gebaseerd op gegevens van de Nederlandse Continue Morbiditeitsregistratie, waarin obese patiënten gematcht werden aan niet-obese patiënten volgens leeftijd, geslacht, sociaaleconomische status in een periode van vijf jaar
    Brief of requirements of the dairy cow
    Cornelissen, J.M.R. ; Ursinus, W.W. ; Schepers, F. ; Groot Koerkamp, P.W.G. ; Dixhoorn, I.D.E. van - \ 2009
    Lelystad : Wageningen UR Livestock Research (Report / Animal Sciences Group 264) - 33
    melkveehouderij - melkvee - dierenwelzijn - duurzaamheid (sustainability) - dairy farming - dairy cattle - animal welfare - sustainability
    This report lists the brief of requirements of the dairy cow, based on her needs (also listed). The BoR indicates the actor’s needs with regards to the animal husbandry system. BoR of the main actors are incorporated in the redesign of a dairy husbandry system in the project Cow Power
    Programma van eisen van de burger/consument met betrekking tot de melkveehouderij : Kracht van Koeien = Brief of Requirements of the citizen/consumer
    Bos, A.P. ; Eijk, O.N.M. van - \ 2009
    Lelystad : Animal Sciences Group (Rapport / Wageningen UR, Animal Sciences Group 185)
    behoeften - melkveehouderij - melkvee - consumenten - systeeminnovatie - duurzame veehouderij - requirements - dairy farming - dairy cattle - consumers - system innovation - sustainable animal husbandry
    Brief of Requirements (BoR) of the citizen / consumer with regards to the dairy husbandry. The BoR indicates the actor’s needs with regards to the ani/ mal husbandry system. BoR of the main actors are incorporated in the re/design of a dairy husbandry system
    Validation and application of a yeast bioassay for screening androgenic activity in calf urine and feed
    Bovee, T.F.H. ; Bor, G. ; Heskamp, H.H. ; Lasaroms, J.J.P. ; Sanders, M.B. ; Nielen, M.W.F. - \ 2009
    Analytica Chimica Acta 637 (2009)1-2. - ISSN 0003-2670 - p. 225 - 234.
    tandem mass-spectrometry - in-vitro - liquid-chromatography - estrogenic activity - recombinant assay - anabolic-steroids - receptor ligands - surface waters - binding - dihydrotestosterone
    Bioassays are valuable tools for combating the illegal use of steroids in cattle fattening. Previously we described the construction and properties of a rapid and robust yeast androgen bioassay stably expressing the human androgen receptor (hAR) and yeast enhanced green fluorescent protein (yEGFP), the latter in response to androgens. In the present study this yeast androgen bioassay was validated as a qualitative screening method for the determination of androgenic activity in calf urine and animal feed. This validation was performed according to EC Decision 2002/657. 20 blank samples were spiked with testosterone, 17¿-methyltestosterone, 19-nortestosterone, 17ß-trenbolone, 17ß-boldenone or 17¿-methylboldenone at 2 or 15 ng mL¿1 in urine and 50 or 100 ng g¿1 in feed. All blank and spiked samples fulfilled the CC¿ and CCß criterions, meaning that all 20 blank samples gave signals below the determined decision limits CC¿ and were thus classified as compliant (¿ = 1%). For each component, at least 19 out of the 20 spiked samples gave a signal above the CC¿ and were thus classified as suspect (ß = 5%). The method was specific, and high amounts of dexamethasone did not interfere with the outcome of the test. Although high levels of 17¿-ethynylestradiol can significantly inhibit the response obtained with low amounts of androgens, that situation is not relevant in veterinary practice. When stored at their specific conditions, the androgens in feed were stable for at least 91 days. Real urine samples from a national control program were screened and a representative part of the compliant and suspect samples were confirmed by gas chromatography¿tandem mass spectrometry
    Inter-laboratory comparison of a yeast bioassay for the determination of estrogenic activity in biological samples
    Bovee, T.F.H. ; Bor, G. ; Becue, I. ; Daamen, E.J. ; Duursen, M. van; Lehmann, S. ; Vollmer, G. ; Maria, R. De; Fox, E. ; Witters, H. ; Bernhoft, S. ; Schramm, K.W. ; Hoogenboom, L.A.P. ; Nielen, M.W.F. - \ 2009
    Analytica Chimica Acta 637 (2009)1-2. - ISSN 0003-2670 - p. 265 - 272.
    tandem mass-spectrometry - green fluorescent protein - liquid-chromatography - anabolic-steroids - recombinant assay - surface waters - beta-agonists - urine - validation - abuse
    An inter-laboratory exercise was performed with a yeast estrogen bioassay, based on the expression of yeast enhanced green fluorescent protein (yEGFP), for the determination of estrogenic activity in extracts of calf urine samples. Urine samples were spiked with 1 and 5 ng mL¿1 17ß-estradiol and 17¿-ethynylestradiol, 10 and 50 ng mL¿1 mestranol, and 100 ng mL¿1 testosterone and progesterone. Sample extracts of blank and spiked urine samples were prepared at our laboratory and sent to seven laboratories together with a reagent blank, a DMSO blank, and eight 17ß-estradiol stock solutions in DMSO ranging in concentration from 0 to 545 ng mL¿1. Sample extracts and standards were coded and tested blindly. A decision limit (CC¿) was determined based on the response of seven blank urine samples. Signals of the negative controls, e.g. urine samples spiked with 100 ng mL¿1 testosterone or progesterone, were all below the determined CC¿ and were thus screened as compliant. Positive controls, i.e. the urine samples spiked at two levels with 17ß-estradiol, 17¿-ethynylestradiol and mestranol, were almost all screened as suspect, i.e. gave signals above the determined CC¿. Determined EC50 values calculated from the 17ß-estradiol dose¿response curves obtained by the seven laboratories ranged from 0.59 to 0.95 nM
    Ervaringskennis van Huib Bor: het kalf bij de koe
    Animal Sciences Group (ASG), - \ 2008
    melkveehouderij - kalveren - melkkoeien - zogen - diergezondheid - diergedrag - biologische landbouw - dairy farming - calves - dairy cows - suckling - animal health - animal behaviour - organic farming
    Een aantal jaar terug koos Huib Bor voor het kalf bij de koe, omdat hij streeft naar een natuurlijke manier van werken. Bovendien staat in de literatuur, dat het celgetal omlaag gaat als een kalf bij de koe zuigt. Huib wilde weten of het zogen effect heeft op het celgetal van de moeder en van het kalf, dat informatie meekrijgt via het drinken bij de moeder. Als het kalf later melkkoe wordt, kan dit effect hebben op het celgetal en de uiergezondheid. Na twee jaar blijkt dat een kalf bij de koe geen effect heeft op het celgetal van de moeder.
    Gezonde klauw door sterk ras, goede voeding en droge omgeving
    Animal Sciences Group (ASG), - \ 2008
    melkveehouderij - melkkoeien - klauwen - diergezondheid - voetziekten - voersamenstelling - biologische landbouw - melkveebedrijven - melkveerassen - dairy farming - dairy cows - claws - animal health - foot diseases - feed formulation - organic farming - dairy farms - dairy breeds
    Huib Bor wil eigenlijk geen antibiotica of andere reguliere diergeneesmiddelen meer gebruiken. Wanneer je als boer een dierenarts of medewerker van gezondheidsdienst of voorlichting vraagt hoe je klauwproblemen als een stinkpoot of mortellaro kunt voorkomen, adviseren ze in bijna alle gevallen voetbaden met formaline en kopersulfaat. Huib wil geen formaline gebruiken, omdat hij dat een gevaarlijke stof vindt. Wat kwam voor voetenbaden in de plaats?
    Management van Mts Bor van Gils: positief bevorderen van de gezondheid
    Animal Sciences Group (ASG), - \ 2008
    melkveehouderij - melkveebedrijven - diergezondheid - biologische landbouw - dierverzorging - agrarische bedrijfsvoering - biologisch-dynamische landbouw - dairy farming - dairy farms - animal health - organic farming - care of animals - farm management - biodynamic farming
    In 1993 schakelde Huib Bor om naar biologische bedrijfsvoering, waarna de dierenartsrekening halveerde. Huib kreeg een andere kijk op diergezondheid binnen zijn bedrijf. Zijn strategie is om helemaal geen antibiotica meer te gebruiken. Volgens hem pak je met antibiotica de oorzaak niet aan en helpt het vaak ook niet. Huib begon toen met het gebruik van etherische oliën en bloesemtherapie en in 2002 startte hij met homeopathie. Via cursussen over etherische oliën en homeopathie heeft hij kennis opgebouwd, die hij in de praktijk bracht. Hierdoor is Huib anders naar ziekte gaan kijken: elke ziekte ontstaat doordat iets niet in evenwicht is (onbalans). Hij probeert de balans terug te vinden door de oorzaak op te sporen. Dit kan door het bedrijf of de omstandigheden aan te passen.
    Neogene stratigraphy of the Langenboom locality (Noord-Brabant, the Netherlands)
    Wijnker, T.G. ; Bor, T.J. ; Wesselingh, F.P. ; Munsterman, D.K. ; Brinkhuis, H. ; Burger, A.W. ; Vonhof, H.B. ; Post, K. ; Hoedemakers, K. ; Janse, A.C. ; Taverne, N. - \ 2008
    Netherlands journal of geosciences 87 (2008)2. - ISSN 0016-7746 - p. 165 - 180.
    geologie - tektoniek - paleozoölogie - noord-brabant - geology - tectonics - palaeozoology - noord-brabant - north-sea basin - dinoflagellate cyst - bering strait - upper miocene - pliocene - belgium - pleistocene - age
    The locality of Langenboom (eastern Noord-Brabant, the Netherlands), also known as Mill, is famous for its Neogene molluscs, shark teeth, teleost remains, birds and marine mammals. The stratigraphic context of the fossils, which have been collected from sand suppletions, was hitherto poorly understood. Here we report on a section which has been sampled by divers in the adjacent flooded sandpit 'De Kuilen' from which the Langenboom sands have been extracted. The studied section covers part of the marine Miocene Breda Formation and Pliocene Oosterhout Formation, and is topped by fluvial Quaternary deposits of presumably the Beegden Formation. The Breda Formation (15 - 18 m below lake surface) in this section is, based on organic walled dinoflagellate cysts, of an early-middle Tortonian age. The Oosterhout Formation (7 - 15 m below lake surface) comprises two depositional sequences, the lower of which (12 - 15 m below lake surface) presumably is the source of most Langenboom fossils. Combined dinoflagellate cyst and benthic mollusc indicators point to an early Zanclean - early Piacenzian age for this lower cycle. Its basal transgressive lag and (to lesser extent) top comprise reworked Tortonian taxa as well. Dinoflagellate cysts and a single benthic mollusc point to a Piacenzian age for the upper Oosterhout Formation sequence (7 - 12 m below lake surface).
    Encounters for common illnesses in general practice increased in obese patients
    Wayenburg, C.A.M. van; Lerniengre, M.B.T. ; Reenen-Schimmel, A.H. van; Bor, J.H.J. ; Bakx, J.C. ; Staveren, W.A. van; Weel, C. van; Binsbergen, J.J. van - \ 2008
    Family Practice 25 (2008)Suppl. 1. - ISSN 0263-2136 - p. i93 - i98.
    health-care services - chronic diseases - population - prevalence - overweight - pain - association - predictors - mortality - weight
    Background. Obese patients are known to have more chronic medical conditions. Objective. To compare the frequency of encounter for episodes of the 10 most common illnesses in general practice between obese and non-overweight patients. Methods. Data were derived from the Continuous Morbidity Registration, containing data from four general practices in and around Nijmegen (The Netherlands). In this research and registration network, a matched cohort study was performed. Each obese patient (body mass index 30 kg/m2), aged 20–75 years, was matched for age, gender, socio-economic status and general practice, to approximately two patients without the diagnosis ‘overweight’ or ‘obesity’. Over a period of 5 years (January 1, 2000 to December 31, 2004), the frequency of encounter for episodes of the 10 most common illnesses was compared, taking chronic medical conditions into account. Results. At the start, 550 patients with obesity could be identified and were matched to 954 controls. Obese patients presented more common illnesses than non-overweight patients (incidence rate ratio 1.28, 95% confidence interval 1.12–1.47), in particular common cold (without fever), myalgia of the upper girdle, dermatophytosis and bruise (contusion, haematoma). Conclusion. Obese patients present more common illnesses to their GP, such as common cold (without fever), myalgia of the upper girdle, dermatophytosis and bruise (contusion, haematoma). This is in addition to their higher co-morbidity of chronic medical conditions
    Programma van Eisen van de ondernemer in de melkveehouderij : Kracht van Koeien
    Bos, A.P. ; Cornelissen, J.M.R. - \ 2008
    Lelystad : Animal Sciences Group (Rapport / Animal Sciences Group 182) - 13
    melkveehouderij - bedrijfssystemenonderzoek - bedrijfssystemen - ontwerp - motivatie - duurzaamheid (sustainability) - dierenwelzijn - wensen - dairy farming - farming systems research - farming systems - design - motivation - sustainability - animal welfare - desires
    Brief of Requirements (BoR) of the entrepreneur in dairy husbandry. The BoR indicates the actor's needs with regards to the animal husbandry system. BoRs of the main actors are incorporated in the redesign of a dairy husbandry system
    An untargeted metabolomics approach to contaminant analysis. Pinpointing potential unknown compounds
    Lommen, A. ; Weg, G. van der; Engelen, M.C. ; Bor, G. ; Hoogenboom, L.A.P. ; Nielen, M.W.F. - \ 2007
    Analytica Chimica Acta 584 (2007)1. - ISSN 0003-2670 - p. 43 - 49.
    flight-mass-spectrometry - gas chromatography-time - gc-tof-ms - liquid-chromatography - thermal-desorption - bioassay - metabolism - pesticides - urine - fruit
    This study deals with an automated data analysis strategy to pinpoint potential unknown compounds in full scan mass spectrometry (MS) experiments. Three examples of an untargeted metabolomics approach to contaminant analysis are given. By comparing a plant-oil based hormone cocktail to 90 plant oil samples ca. 25 compounds specific to the hormone cocktail could be detected. Five of these compounds were confirmed as steroid hormones. A comparison of a drink water sample from a farm to distillated water showed the presence of contaminants specific to this drink water sample. A grass sample, which was known to give a false positive result in a DR-CALUX bioassay, was unexpectedly shown to contain an abnormal level of chrysene, which was obviously not eliminated during clean-up.
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