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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Marginal selenium deficiency down-regulates inflammation-related genes in splenic leukocytes of the mouse
Kipp, A.P. ; Banning, A. ; Brigelius, R. ; Keijer, J. ; Schothorst, E.M. van - \ 2018
GSE117026 - PRJNA480872 - Mus musculus
Moderate selenium deficiency may lead to an impaired capacity to cope with health challenges. Functional effects of suboptimal selenium intake are not fully known, and biomarkers for an insufficient selenium supply are inadequate. We therefore fed mice diets of moderately deficient or adequate selenium intake for 6 weeks. Changes in global gene expression were monitored by microarray analysis in splenic leukocytes. Genes for four selenoproteins, Sepw1, Gpx1, Selh and Sep15, were the most significantly down-regulated in moderate selenium deficiency, and this was confirmed by quantitative polymerase chain reaction (qPCR). Classification of significantly affected genes revealed that processes related to inflammation, heme biosynthesis, DNA replication and transcription, cell cycle and transport were affected by selenium restriction. Down-regulation by moderate selenium deficiency of specific genes involved in inflammation and heme biosynthesis was confirmed by qPCR. Myeloperoxidase and lysozyme activities were decreased in selenium-restricted leukocytes, providing evidence for functional consequences. Genes for 31 nuclear factor (NF)-κB targets were down-regulated in moderate selenium deficiency, indicating an impaired NF-κB signaling. Together, the observed changes point to a disturbance in inflammatory response. The selenoproteins found here to be sensitive to selenium intake in murine leukocytes might also be useful as biomarkers for a moderate selenium deficiency in humans.
Four selenoproteins, protein biosynthesis, and Wnt signalling are particularly sensitive to limited selenium intake in mouse colon
Kipp, A. ; Banning, A. ; Brigelius, R. ; Keijer, J. ; Schothorst, E.M. van - \ 2018
GSE117025 - PRJNA480871 - Mus musculus
Selenium is an essential micronutrient. Its recommended daily allowance is not attained by a significant proportion of the population in many countries and its intake has been suggested to affect colorectal carcinogenesis. Therefore, microarrays were used to determine how both selenoprotein and global gene expression patterns in the mouse colon were affected by marginal selenium deficiency comparable to variations in human dietary intakes. Two groups of 12 mice each were fed a selenium-deficient (0.086mg Se/kg) or a selenium-adequate (0.15mg Se/kg) diet. After 6wk, plasma selenium level, liver, and colon glutathione peroxidase (GPx) activity in the deficient group was 12, 34, and 50%, respectively, of that of the adequate group. Differential gene expression was analysed with mouse 44K whole genome microarrays. Pathway analysis by GenMAPP identified the protein biosynthesis pathway as most significantly affected, followed by inflammation, Delta-Notch and Wnt pathways. Selected gene expression changes were confirmed by quantitative real-time PCR. GPx1 and the selenoproteins W, H, and M, responded significantly to selenium intake making them candidates as biomarkers for selenium status. Thus, feeding a marginal selenium-deficient diet resulted in distinct changes in global gene expression in the mouse colon. Modulation of cancer-related pathways may contribute to the higher susceptibility to colon carcinogenesis in low selenium status.
Muscle mitochondrial stress adaptation operates independently of endogenous FGF21 action
Ost, Mario ; Coleman, Verena ; Voigt, Anja ; Schothorst, E.M. van; Keipert, Susanne ; Stelt, Inge van der; Ringel, Sebastian ; Graja, Antonia ; Ambrosi, Thomas ; Kipp, A.P. ; Jastroch, Martin ; Schulz, T.J. ; Keijer, Jaap ; Klaus, Susanne - \ 2016
Molecular Metabolism 5 (2016)2. - ISSN 2212-8778 - p. 79 - 90.
Browning - FGF21 - GDF15 - Mitochondrial disease - Muscle mitohormesis - Myokine

Objective: Fibroblast growth factor 21 (FGF21) was recently discovered as stress-induced myokine during mitochondrial disease and proposed as key metabolic mediator of the integrated stress response (ISR) presumably causing systemic metabolic improvements. Curiously, the precise cell-non-autonomous and cell-autonomous relevance of endogenous FGF21 action remained poorly understood. Methods: We made use of the established UCP1 transgenic (TG) mouse, a model of metabolic perturbations made by a specific decrease in muscle mitochondrial efficiency through increased respiratory uncoupling and robust metabolic adaptation and muscle ISR-driven FGF21 induction. In a cross of TG with Fgf21-knockout (FGF21-/-) mice, we determined the functional role of FGF21 as a muscle stress-induced myokine under low and high fat feeding conditions. Results: Here we uncovered that FGF21 signaling is dispensable for metabolic improvements evoked by compromised mitochondrial function in skeletal muscle. Strikingly, genetic ablation of FGF21 fully counteracted the cell-non-autonomous metabolic remodeling and browning of subcutaneous white adipose tissue (WAT), together with the reduction of circulating triglycerides and cholesterol. Brown adipose tissue activity was similar in all groups. Remarkably, we found that FGF21 played a negligible role in muscle mitochondrial stress-related improved obesity resistance, glycemic control and hepatic lipid homeostasis. Furthermore, the protective cell-autonomous muscle mitohormesis and metabolic stress adaptation, including an increased muscle proteostasis via mitochondrial unfolded protein response (UPRmt) and amino acid biosynthetic pathways did not require the presence of FGF21. Conclusions: Here we demonstrate that although FGF21 drives WAT remodeling, the adaptive pseudo-starvation response under elevated muscle mitochondrial stress conditions operates independently of both WAT browning and FGF21 action. Thus, our findings challenge FGF21 as key metabolic mediator of the mitochondrial stress adaptation and powerful therapeutic target during muscle mitochondrial disease.

Amino acid deprivation due to overexpression of UCP1 in skeletal muscle: signalling via FGF-21
Ost, M. ; Schothorst, Evert van; Keipert, S. ; Romijnders-van der Stelt, Inge ; Klaus, S. ; Keijer, Jaap - \ 2015
GSE45991 - Mus musculus - PRJNA196841
Recent studies on mouse and human skeletal muscle (SM) demonstrated the important link between mitochondrial function and the cellular metabolic adaptation. To identify key compensatory molecular mechanisms in response to chronic mitochondrial distress, we analyzed mice with ectopic SM respiratory uncoupling in uncoupling protein 1 transgenic (UCP1-TG) mice as model of muscle-specific compromised mitochondrial function. Here we describe a detailed metabolic reprogramming profile associated with mitochondrial perturbations in SM, triggering an increased protein turnover and amino acid metabolism with induced biosynthetic serine/1-carbon/glycine pathway and the longevity-promoting polyamine spermidine as well as the trans-sulfuration pathway. This is related to an induction of NADPH-generating pathways and glutathione metabolism as an adaptive mitohormetic response and defense against increased oxidative stress. Strikingly, consistent muscle retrograde signaling profiles were observed in acute stress states such as muscle cell starvation and lipid overload, muscle regeneration, and heart muscle inflammation, but not in response to exercise. We provide conclusive evidence for a key compensatory stress-signaling network that preserves cellular function, oxidative stress tolerance, and survival during conditions of increased SM mitochondrial distress, a metabolic reprogramming profile so far only demonstrated for cancer cells and heart muscle.-Ost, M., Keipert, S., van Schothorst, E. M., Donner, V., van der Stelt, I., Kipp, A. P., Petzke, K.-J., Jove, M., Pamplona, R., Portero-Otin, M., Keijer, J., and Klaus, S. Muscle mitohormesis promotes cellular survival via serine/glycine pathway flux.
Muscle mitohormesis promotes cellular survival via serine/glycine pathway flux
Ost, M. ; Keipert, S. ; Schothorst, E.M. van; Donner, V. ; Stelt, I. van der; Kipp, A. ; Petzke, K.J. ; Jove, M. ; Pamplona, R. ; Portero-Otin, M. ; Keijer, J. ; Klaus, S. - \ 2015
FASEB Journal 29 (2015)4. - ISSN 0892-6638 - p. 1314 - 1328.
uncoupling protein-1 expression - ubiquitin-proteasome pathway - human skeletal-muscle - antioxidant defense - signaling pathways - gene-expression - receptor-gamma - mouse model - cathepsin-l - key role
Recent studies on mouse and human skeletal muscle (SM) demonstrated the important link between mitochondrial function and the cellular metabolic adaptation. To identify key compensatory molecular mechanisms in response to chronic mitochondrial distress, we analyzed mice with ectopic SM respiratory uncoupling in uncoupling protein 1 transgenic (UCP1-TG) mice as model of muscle-specific compromised mitochondrial function. Here we describe a detailed metabolic reprogramming profile associated with mitochondrial perturbations in SM, triggering an increased protein turnover and amino acid metabolism with induced biosynthetic serine/1-carbon/glycine pathway and the longevity-promoting polyamine spermidine as well as the trans-sulfuration pathway. This is related to an induction of NADPH-generating pathways and glutathione metabolism as an adaptive mitohormetic response and defense against increased oxidative stress. Strikingly, consistent muscle retrograde signaling profiles were observed in acute stress states such as muscle cell starvation and lipid overload, muscle regeneration, and heart muscle inflammation, but not in response to exercise. We provide conclusive evidence for a key compensatory stress-signaling network that preserves cellular function, oxidative stress tolerance, and survival during conditions of increased SM mitochondrial distress, a metabolic reprogramming profile so far only demonstrated for cancer cells and heart muscle.
Measuring water-vapour and carbon-dioxide fluxes at field scales with scintillometry
Kesteren, A.J.H. van - \ 2012
Wageningen University. Promotor(en): Bert Holtslag, co-promotor(en): Oscar Hartogensis. - [S.l.] : s.n. - ISBN 9789461734235 - 212
scintillometrie - waterdamp - kooldioxide - meteorologie - meettechnieken - scintillometry - water vapour - carbon dioxide - meteorology - measurement techniques

Scintillometry is a measurement technique that has proven itself to be of great value for measuring spatial-averaged fluxes of sensible heat, momentum, and evapotranspiration. Furthermore, for crop fields (field scales), scintillometry has been shown to accurately determine the sensible-heat and momentum flux over time intervals as short as 6 seconds. As a consequence, interests in scintillometry are growing and scintillometers that determine sensible-heat fluxes and momentum fluxes have become commercially available.

This thesis deals with two aspects of scintillometry. First, after a general introduction of scintillometry, measurement errors that have been observed in the large-aperture scintillometer from Kipp&Zonen and in the SLS field-scale scintillometer from Scintec are evaluated. For both scintillometer types, we discuss the variability in the measurement errors among different instruments and, where possible, we give solutions to remove these errors. Furthermore, we present the results of a prototype scintillometer that was developed as part of the research project. With our proposed design, we aim to overcome the measurement errors in the Scintec scintillometer and extend the applicability of the field-scale scintillometer to paths that are longer than 200 m.

Second, we extend the application of field-scale scintillometry to the flux measurements of latent-heat, carbon-dioxide, and other passive scalars. Until now, scintillometers could not be used for measuring passive-scalar fluxes over crop fields and we show that with our extended methodology these fluxes can be accurately determined over time intervals as short as 1 minute. The methodology is based on a combination of scintillometer measurements and additional high-frequency scalar measurements and works under conditions of homogeneous turbulence, i.e. single crop fields. We introduce four methods, notably the energy-balance method, the Bowen-variance method, the flux-variance method, and the structure-parameter method. Using several validation methods, we show that the energy-balance method is unsuitable for estimating scalar fluxes over 1-min averaging intervals. The Bowen-variance and flux-variance method perform better and the structure-parameter method accurately resolves 1-minute fluxes. Thus, with this methodology fluxes can be resolved with a high temporal resolution, making it possible to study vegetation in a natural environment under non-stationary conditions. This allows us to show that the wheat vegetation affects fluxes upon changes in solar radiation in time periods clearly shorter than 30 minutes and that the canopy resistance can change significantly within several minutes.


Marginal selenium deficiency down-regulates inflammation-related genes in splenic leukocytes of the mouse
Kipp, A.P. ; Banning, A. ; Schothorst, E.M. van; Meplan, C. ; Coort, S.L. ; Evelo, C. ; Keijer, J. ; Hesketh, J. ; Brigelius, R. - \ 2012
Journal of Nutritional Biochemistry 23 (2012)9. - ISSN 0955-2863 - p. 1170 - 1177.
kappa-b activation - smooth-muscle-cells - response syndrome - immune-response - glutathione-peroxidase - protein-biosynthesis - t-cell - expression - selenoproteins - macrophages
Moderate selenium deficiency may lead to an impaired capacity to cope with health challenges. Functional effects of suboptimal selenium intake are not fully known, and biomarkers for an insufficient selenium supply are inadequate. We therefore fed mice diets of moderately deficient or adequate selenium intake for 6 weeks. Changes in global gene expression were monitored by microarray analysis in splenic leukocytes. Genes for four selenoproteins, Sepw1, Gpx1, Selh and Sep15, were the most significantly down-regulated in moderate selenium deficiency, and this was confirmed by quantitative polymerase chain reaction (qPCR). Classification of significantly affected genes revealed that processes related to inflammation, heme biosynthesis, DNA replication and transcription, cell cycle and transport were affected by selenium restriction. Down-regulation by moderate selenium deficiency of specific genes involved in inflammation and heme biosynthesis was confirmed by qPCR. Myeloperoxidase and lysozyme activities were decreased in selenium-restricted leukocytes, providing evidence for functional consequences. Genes for 31 nuclear factor (NF)-¿B targets were down-regulated in moderate selenium deficiency, indicating an impaired NF-¿B signaling. Together, the observed changes point to a disturbance in inflammatory response. The selenoproteins found here to be sensitive to selenium intake in murine leukocytes might also be useful as biomarkers for a moderate selenium deficiency in humans.
Analysis of the Systematic Errors Found in the Kipp & Zonen Large-Aperture Scintillometer
Kesteren, A.J.H. van; Hartogensis, O.K. - \ 2011
Boundary-Layer Meteorology 138 (2011)3. - ISSN 0006-8314 - p. 493 - 509.
heterogeneous land-surface - sensible heat fluxes - optical scintillometer - refractive-index - c-n(2) - area
Studies have shown a systematic error in the Kipp & Zonen large-aperture scintillometer (K&ZLAS) measurements of the sensible heat flux, H. We improved on these studies and compared four K&ZLASs with a Wageningen large-aperture scintillometer at the Chilbolton Observatory. The scintillometers were installed such that their footprints were the same and independent flux measurements were made along the measurement path. This allowed us to compare H and the direct scintillometer output, the refractive index structure parameter, C2n. Furthermore, spectral analysis was performed on the raw scintillometer signal to investigate the characteristics of the error. Firstly, correlation coefficients =0.99 confirm the robustness of the scintillometer method, and secondly we discovered two systematic errors: the low-C2n error and the high-C2n error. The low-C2n error is a non-linear error that is caused by high-frequency noise, and we suspect the error to be caused by the calibration circuit in the receiver. It varies between each K&ZLAS, is significant for H = 50 W m-2, and we propose a solution to remove this error using the demodulated signal. The high-C2n error identified by us is the systematic error found in previous studies.We suspect this error to be caused by poor focal alignment of the receiver detector and the transmitter light-emitting diode that causes ineffective use of the Fresnel lens in the current Kipp & Zonen design. It varies between each K&ZLAS (35% up to 240%) and can only be removed by comparing with a reference scintillometer in the field.
Optimal climate regions in Mexico for greenhouse crop production
Kipp, J.A. - \ 2010
Bleiswijk : Wageningen UR Greenhouse Horticulture (Rapporten GTB-1024) - 9
landbouwgeografie - centraal-amerika - mexico - klimaatfactoren - kasgewassen - landbouwproductie - kassen - agricultural geography - central america - climatic factors - greenhouse crops - agricultural production - greenhouses
Four selenoproteins, protein biosynthesis, and Wnt signalling are particularly sensitive to selenium intake in mice colon
Kipp, A. ; Banning, A. ; Schothorst, E.M. van; Meplan, C. ; Schomburg, L. ; Evelo, C. ; Coort, S.L. ; Gaj, S. ; Keijer, J. ; Hesketh, J. ; Brigelius, R. - \ 2009
Molecular Nutrition & Food Research 53 (2009)12. - ISSN 1613-4125 - p. 1561 - 1572.
messenger-rna stability - thioredoxin-like family - glutathione-peroxidase - gene-expression - microarray data - colorectal adenoma - cancer prevention - molecular targets - oxidative stress - selenocysteine
Selenium is an essential micronutrient. Its recommended daily allowance is not attained by a significant proportion of the population in many countries and its intake has been suggested to affect colorectal carcinogenesis. Therefore, microarrays were used to determine how both selenoprotein and global gene expression patterns in the mouse colon were affected by marginal selenium deficiency comparable to variations in human dietary intakes. Two groups of 12 mice each were fed a selenium-deficient (0.086 mg Se/kg) or a selenium-adequate (0.15 mg Se/kg) diet. After 6 wk, plasma selenium level, liver, and colon glutathione peroxidase (GPx) activity in the deficient group was 12, 34, and 50%, respectively, of that of the adequate group. Differential gene expression was analysed with mouse 44K whole genome microarrays. Pathway analysis by GenMAPP identified the protein biosynthesis pathway as most significantly affected, followed by inflammation, Delta-Notch and Wnt pathways. Selected gene expression changes were confirmed by quantitative real-time PCR. GPx1 and the selenoproteins W, H, and M, responded significantly to selenium intake making them candidates as biomarkers for selenium status. Thus, feeding a marginal selenium-deficient diet resulted in distinct changes in global gene expression in the mouse colon. Modulation of cancer-related pathways may contribute to the higher susceptibility to colon carcinogenesis in low selenium status
Kijk in de kas : een interactieve leeromgeving over tuinbouw en energie
Buwalda, F. ; Mark, C. van der; Swinkels, G.J. ; Zwart, H.F. de; Gastel, T. van; Burema, C. ; Kamminga, H. ; Kipp, J.A. - \ 2009
Wageningen : Wageningen UR Glastuinbouw (Rapport / Wageningen UR Glastuinbouw 247) - 64
glastuinbouw - teeltsystemen - energiebehoud - voorlichting - internet - landbouwvoorlichting - greenhouse horticulture - cropping systems - energy conservation - extension - agricultural extension
Vermindering van de afhankelijkheid van fossiele brandstoffen vraagt in de glastuinbouw om een omschakeling. De vertrouwde stookregels moeten daarbij grondig tegen het licht worden gehouden. Ervaringskennis die tuinders gebruiken bij het instellen van de klimaatregeling is gegroeid in een periode dat energie nog een stuk goedkoper was. Telers kunnen daarom maar heel beperkt op die kennis terugvallen. Het is dus belangrijk dat nieuwe ervaringskennis efficiënt wordt opgebouwd en gedeeld binnen de sector. De kennisinstellingen kunnen een rol spelen door ondersteunende berekeningen uit te voeren en achterliggende fysiologische en fysische principes uit te leggen. Het door LNV, PT en WUR-glastuinbouw gezamenlijk opgezette project Kijk in de Kas had tot doel om deze kennisuitwisseling via internet op een efficiënte en aansprekende manier voor de sector toegankelijk te maken. Het project is uitgevoerd door Wageningen UR Glastuinbouw in samenwerking met Reed Business, LetsGrow.com en verschillende telers, en teeltadviseurs. Uit een evaluatie na ruim een jaar ‘in de lucht’ te zijn geweest is gebleken dat bezoekers vooral waardering hadden voor de combinatie van weblogs, live grafieken en achtergrondkennis die werd aangeboden. Het project heeft telers aan het denken gezet over hun eigen klimaatregeling en heeft belangrijke ervaring opgeleverd over de mogelijkheden van kennisinteractie via internet. Bij toepassing van deze ervaring in eventuele vervolginitiatieven is een belangrijke uitdaging om de aangeboden boodschap nog beter af te stemmen op de informatiebehoefte van de doelgroep
SynErgie : eindrapportage fase I en II
Bakker, J.C. ; Maters, H.J. ; Kipp, J.A. ; Gieling, T.H. ; Hoes, A.C. - \ 2009
Wageningen : Wageningen UR Glastuinbouw (Nota / Plant Research International 569) - 38
tuinbouw - energie - monitoring - glastuinbouw - protocollen - energiebesparing - kastechniek - horticulture - energy - greenhouse horticulture - protocols - energy saving - greenhouse technology
Een versnelde realisatie en implementatie van energiezuinige kasconcepten is belangrijk om de innovatiekracht in de glastuinbouwsector te houden. Het project SynErgie zoekt naar een 'omgeving' waarin de voorlopers elkaar versterken en de gelegenheid krijgen om gedeelde problematiek ter sprake te brengen. SynErgie richt zich op het bieden van een referentiekader aan de eerste groep investeerder, de 'innovatoren', in het semi-gesloten of geconditioneerd telen. SynErgie richt zich primair op het wegnemen van de belangrijkste procesmatige en organisatorische belemmeringen. Hiervoor brengt SynErgie een proces op gang van kruisbestuiving via integratie van kennis en ervaring over de systemen bij de innovatoren en verspreiding van kennis naar de eerste navolgers. Vanuit deze kruisbestuiving wordt een door ondernemers gedreven vraagarticulatie gerealiseerd en zijn specifieke en generieke kennisleemtes geïdentificeerd (technisch, teeltkundig, economisch, juridisch en procesmatig). Deze kennisleemtes zijn zomogelijk ingevuld via discussies met onderzoekers in platform- bijeenkomsten en door initiatieven tot aanvullend onderzoek.
Exchange of Knowledge between Research and Horticultural Practice through the Internet
Buwalda, F. ; Swinkels, G.L.A.M. ; Zwart, H.F. de; Kipp, J.A. ; Kempkes, F.L.K. - \ 2008
Acta Horticulturae 2008 (2008)801. - ISSN 0567-7572 - p. 531 - 538.
Horticultural production is a complex process, the efficiency of which is rarely attributable to a single factor. In addition, optima tend to vary with internal states and outside conditions. To manage their production process, growers generally rely on rules based on experience. However, much of this experience has been acquired under conditions of relatively low fuel prices. In view of increasing fuel costs and worldwide initiatives to reduce CO2 emission, horticultural producers are faced with the need to adapt their practice in order to remain economically viable. The horticultural research community can provide knowledge which may help growers to adapt to the changing conditions. In The Netherlands, internet technology is being used to facilitate efficient communication between growers and scientists. Information is collected automatically from process computers at five commercial nurseries, dynamic models are used to monitor crop and climate conditions, and nearly real-time results are published on a web portal, where it is linked with an information database and web logs by growers, advisors and researchers. The web portal (in Dutch) can be viewed at http://www.kijkindekas.nl.
First Results of an Optical and Millimeter Wave Scintillometer system at the Chilbolton test range
Hartogensis, O.K. ; Kesteren, A.J.H. van; Evans, J. ; Bradford, J. ; Moene, A.F. ; Holtslag, A.A.M. - \ 2008
In: 18th Symposium on Boundary Layers and Turbulence, Stockholm, Sweden, 9 - 13 June, 2008. - Boston : American Meteorological Society - p. 8B.2 - 8B.2.
Scintillometry has become a generally accepted technique to obtain turbulent fluxes at the 0.1 ¿ 10 km scale. Optical large aperture scintillometers (LAS) that yield the sensible heat flux (H) have been tested under a wide range of circumstances (De Bruin, 2002) and are commercially available. With a millimeter wave scintillometer (MWS) in combination with an optical scintillometer the evapotranspiration (LvE), can be determined. The aim is to develop such a combined Optical Millimeter Wave Scintillometer (OMS) system for operational use. In this study we will present the scientific challenges we face in developing the OMS and present the first results of an experiment we conducted at the Chilbolton test-range of the Rutherford Appleton Laboratory (RAL) in the UK in the summer of 2007. At this experiment we deployed a prototype MWS built by RAL in combination with two types of LAS's. For an operational OMS several scientific issues have to be solved, e.g. scintillations caused by water vapor absorption, direct observation of the correlation between atmospheric temperature and humidity fluctuations, saturation of the LAS signal for long paths and the sensitivity of the OMS to mast vibrations. The 500m long Chilbolton test range acts as an outdoor laboratory with highly controlled conditions, perfect for testing scintillometer prototypes: the instrument cabins are placed at exactly the same height (4m) and the benches are supported by large concrete pillars, thereby ruling out sensor vibration. We deployed a mirror based LAS built by Wageningen University and a Fresnel lens based LAS, which is sold by Kipp and Zonen, Delft, the Netherlands. The MWS prototype built by RAL in collaboration with the Centre for Ecology and Hydrology, Wallingford, U.K., operates at 94 GHz and has the special feature that it uses a GPS receiver as a reference to lock the transmitter and receiver frequencies. This makes the RAL94 a low power MWS, as no temperature controlled crystal is needed for frequency synthesis. All raw signals of the scintillometers were measured and stored at 500Hz, providing maximum freedom in the data processing, e.g. allowing spectral filtering. As a reference for the scintillometer output, we also installed eddy-covariance (EC) equipment in the middle of the test-range to independently determine fluxes of heat, latent-heat and momentum as well as the structure parameters of temperature, CT2, humidity, Cq2, and cross-term structure parameter, CTq. Results are presented here showing the comparison of these variables, as measured by the different techniques, and the first assessment of the usefulness of the OMS combination to measure LvE
SynErgie : monitoringsprotocol voor meten in semigesloten kassen
Kipp, J.A. ; Gieling, T.H. ; Bruins, M.A. - \ 2008
Bleiswijk : Wageningen UR Glastuinbouw (Nota / Wageningen UR Glastuinbouw 550) - 28
kassen - monitoring - meting - luchttemperatuur - vochtigheid - wateropname (planten) - energie - glastuinbouw - protocollen - meetsystemen - kastechniek - greenhouses - measurement - air temperature - humidity - water uptake - energy - greenhouse horticulture - protocols - measurement systems - greenhouse technology
SynErgie : rapportage fase 1
Kipp, J.A. ; Bakker, J.C. ; Gieling, T.H. ; Bruins, M.A. - \ 2008
Bleiswijk : Wageningen UR Glastuinbouw (Nota / Plant Research International 554) - 44
kassen - monitoring - meting - energie - glastuinbouw - protocollen - meetsystemen - kastechniek - greenhouses - measurement - energy - greenhouse horticulture - protocols - measurement systems - greenhouse technology
Syscope Magazine (Journal)
Kipp, J.A. - \ 2007
Syscope Magazine (2007).
Geconditioneerd telen is 'hot' maar nog niet probleemloos
Kipp, J.A. - \ 2007
Syscope Magazine 2007 (2007)13. - p. 33 - 33.
SynErgie: een platform van ondernemers en kennisinstellingen
Kipp, J.A. - \ 2007
Bio-optimaal kas
Weel, P.A. van; Raaphorst, M.G.M. ; Kipp, J.A. - \ 2007
groenteteelt - biologische landbouw - emissie - kassen - teelt onder bescherming - duurzaamheid (sustainability) - energiebehoud - glastuinbouw - energiebesparing - glasgroenten - vegetable growing - organic farming - emission - greenhouses - protected cultivation - sustainability - energy conservation - greenhouse horticulture - energy saving - greenhouse vegetables
In de biologische groenteteelt moet het gasverbruik en de daaraan gerelateerde CO2 uitstoot omlaag
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