Staff Publications

Staff Publications

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

    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

    We have a manual that explains all the features 

    Current refinement(s):

    Records 1 - 20 / 271

    • help
    • print

      Print search results

    • export
      A maximum of 250 titles can be exported. Please, refine your queryYou can also select and export up to 30 titles via your marked list.
    Check title to add to marked list
    A comparative analysis of human adult testicular cells expressing stem Leydig cell markers in the interstitium, vasculature, and peritubular layer
    Eliveld, Jitske ; Daalen, Saskia K.M. van; Winter-Korver, Cindy M. de; Veen, Fulco van der; Repping, Sjoerd ; Teerds, Katja ; Pelt, Ans M.M. van - \ 2020
    Andrology 8 (2020)5. - ISSN 2047-2919 - p. 1265 - 1276.
    human testis - markers - propagation - stem Leydig cells

    Background: Origin of human adult Leydig cells (ALCs) is not well understood. This might be partly due to limited data available on the identification and location of human precursor and stem Leydig cells (SLCs) which hampers the study on the development of ALCs. Objectives: The aim of the present study was to investigate whether described human (PDGFRα, NGFR) and rodent (NES, PDGFRα, THY1, NR2F2) SLC markers are expressed by a common cell population within human adult testicular interstitial cells in vivo and before and after in vitro propagation. Materials and methods: Immunohistochemical analyses were used to identify localization of human adult testicular interstitial cells expressing described SLC markers. Next, interstitial cells were isolated and cultured. The percentage of cells expressing one or more SLC markers was determined before and after culture using flow cytometry. Results: NR2F2 and PDGFRα were present in peritubular, perivascular, and Leydig cells, while THY1 was expressed in peritubular and perivascular cells. Although NES and NGFR were expressed in endothelial cells, co-localization with PDGFRα was found for both in vitro, although for NGFR only after culture. All marker positive cells were able to undergo propagation in vitro. Discussion: The partly overlap in localization and overlap in expression in human testicular cells indicate that PDGFRα, NR2F2, and THY1 are expressed within the same ALC developmental lineage from SLCs. Based on the in vitro results, this is also true for NES and after in vitro propagation for NGFR. Conclusion: Our results that earlier described SLC markers are expressed in overlapping human interstitial cell population opens up further research strategies aiming for a better insight in the Leydig cell lineage and will be helpful for development of strategies to cure ALC dysfunction.

    Op veel punten afwijkend, maar geen aparte teeltmaatregelen vereist : varens buitenbeentjes in de tuinbouw
    Kierkels, T. ; Heuvelink, E. - \ 2016
    Onder Glas 13 (2016)1. - p. 34 - 35.
    tuinbouw - glastuinbouw - teeltsystemen - varens als sierplanten - potplanten - sporulatie - kenmerken - plantenvermeerdering - vochtigheid - schaduwplanten - horticulture - greenhouse horticulture - cropping systems - ornamental ferns - pot plants - sporulation - traits - propagation - humidity - shade plants
    Varens wijken in veel opzichten af van andere potplanten. Ze vormen geen bloemen en de voortplanting is een ingewikkelde zaak. Ook inwendig kennen ze tal van bijzonderheden. Daarom is het des te verwonderlijker dat ze op de bedrijven gewoon tussen andere groene planten kunnen worden geteeld.
    Risico op verspreiding van Xanthomonas tijdens CATT aardbeiplanten
    Evenhuis, B. ; Wolf, J.M. van der; Kastelein, P. ; Krijger, M.C. ; Mendes, O. ; Verstappen, E.C.P. ; Otma, E. ; Kruistum, G. van; Verschoor, J. - \ 2015
    Wageningen : Praktijkonderzoek Plant & Omgeving (Applied Plant Research) Business Unit AGV (PPO 3250293000) - 30
    aardbeien - plantenvermeerdering - xanthomonas fragariae - gecontroleerde omgeving - nematoda - gewasbescherming - plagenbestrijding - plantenparasitaire nematoden - meloidogyne hapla - pratylenchus penetrans - biologische bestrijding - strawberries - propagation - xanthomonas fragariae - controlled atmospheres - nematoda - plant protection - pest control - plant parasitic nematodes - meloidogyne hapla - pratylenchus penetrans - biological control
    Risico tijdens CATT op overdracht van Xanthomonas zeer gering De belangrijkste conclusie uit het onderzoek naar de overdracht van Xanthomonas van plant naar plant tijdens CATT is dat dit risico uitermate klein is. Bij latent geïnfecteerd plantmateriaal werden geen aanwijzingen gevonden voor de verspreiding van Xanthomonas tijdens CATT. Dit suggereert dat in een partij zonder symptomatische planten het risico op verspreiding van Xanthomonas nagenoeg afwezig is. Werd zwaar besmet symptomatisch plantmateriaal blootgesteld aan CATT dan werd af en toe met de Bio-TaqMan een aanwijzing voor besmetting van doelplanten gevonden. Dit leidde overigens in geen van deze gevallen tot het daadwerkelijk isoleren van de Xanthomonas bacterie. Ook werd geen symptoomontwikkeling in de doelplanten waargenomen, nadat deze waren uitgeplant en nageteeld. Dit geeft aan dat hoewel verspreiding tijdens CATT niet geheel uit te sluiten is, het risico van infectie van Xanthomonas-vrije planten zeer klein is.
    Front spreading with nonlinear sorption for oscillating flow
    Cirkel, D.G. ; Zee, S.E.A.T.M. van der; Meeussen, J.C.L. - \ 2015
    Water Resources Research 51 (2015)4. - ISSN 0043-1397 - p. 2986 - 2993.
    thermal-energy storage - porous mediums - transport - groundwater - solute - propagation
    In this paper, we consider dispersive and chromatographic mixing at an interface, under alternating flow conditions. In case of a nonreactive or linearly sorbing solute, mixing is in complete analogy with classical dispersion theory. For nonlinear exchange, however, oscillating convective flow leads to an alternation of sharpening (Traveling Wave TW) and spreading (Rarefaction Wave RW). As the limiting TW form is not necessarily accomplished at the end of the TW half cycle, the oscillating fronts show gradual continuous spreading that converges to a zero-convection nonlinear pure diffusion spreading, which is mathematically of quite different nature. This behavior is maintained in case the total (background) concentration differs at both sides of the initial exchange front.
    CATT: a New and Non-Chemical Pest and Nematode Control Method in Strawberry Planting Stock
    Kruistum, G. van; Evenhuis, B. ; Hoek, J. ; Kastelein, P. ; Wolf, J.M. van der; Verschoor, J.A. - \ 2014
    aardbeien - biologische bestrijding - gewasbescherming - plantenparasitaire nematoden - nematoda - plantenvermeerdering - vegetatieve vermeerdering - phytonemus pallidus - meloidogyne hapla - xanthomonas fragariae - strawberries - biological control - plant protection - plant parasitic nematodes - nematoda - propagation - vegetative propagation - phytonemus pallidus - meloidogyne hapla - xanthomonas fragariae
    As an alternative to MeBr fumigation a 48h Controlled Atmosphere Temperature Treatment (CATT) was developed and scaled up by Wageningen UR in cooperation with the Dutch plant propagating association Plantum. This results in an excellent de-infestation and 99.8 % mortality of the strawberry tarsonemid mite (Phytonemus pallidus). This non-chemical and sustainable method provides a healthy production of highly qualified strawberry runners in the field. From 2009 CATT is up scaled to a commercial level and widely applied by Dutch nurseries. In 2011 this CATT method was successfully modified to eradicate also the root knot nematode Meloidogyne hapla (>99.7% mortality), which was not effectively controlled by MeBr fumigation. For an effective killing of the root knot nematodes, temperature must be raised to 40 ºC. In several experiments the optimum conditions for a high mortality of both tarsonemids and nematodes was studied. This leads into an adapted CATT of 20 hours at a temperature of 35 ºC and 50 % CO2 followed by 20 hours at a temperature of 40 ºC. In 2012 this adapted CATT was successfully upgraded and tested under field conditions. Additional research in 2013 leads to the conclusion that cross infection of plants by the bacterial Q-disease Xanthomonas fragariae during CATT treatment is unlikely
    Beter zaad voor Afrika
    Boo, M. de; Thijssen, M.H. - \ 2014
    WageningenWorld (2014)4. - ISSN 2210-7908 - p. 28 - 31.
    kwaliteit - zaden - plantenvermeerdering - rassen (planten) - zaadproductie - zaadkwaliteit - overheid - afrika - tuinbouw - plantenveredeling - pootknollen - geografische rassen - quality - seeds - propagation - varieties - seed production - seed quality - public authorities - africa - horticulture - plant breeding - seed tubers - geographical races
    Veel Afrikaanse boeren blijven verstoken van goed zaai- en pootgoed. Nationale overheden en bedrijven kunnen niet aan de vraag voldoen. Het Centre for Development Innovation in Wageningen werkt met boerengroepen om lokaal beter zaaizaad op de markt te brengen.
    PSTVd (aardappelspindelknolviroïde) in Dahlia : deskstudie
    Leeuwen, P.J. van - \ 2014
    Lisse : Praktijkonderzoek Plant & Omgeving, Sector Bollen, bomen & fruit - 17
    sierteelt - dahlia - aardappelspindelknolviroïde - viroïden - verspreiding - plantenvermeerdering - preventie - bedrijfshygiëne - gewasbescherming - landbouwkundig onderzoek - ornamental horticulture - dahlia - potato spindle tuber viroid - viroids - dispersal - propagation - prevention - industrial hygiene - plant protection - agricultural research
    PSTVd (potato spindle tuber viroid = aardappelspindelknollenviroïde) is een quarantaine organisme dat veel schade geeft in aardappel en tomaat. Dit viroïde is ook aangetroffen in Dahlia. Deze deskstudie is een eerste aanzet om aan te geven wat bekend is over dit viroïde, de waardplantenreeks, schade en symptomen, de wijze van verspreiding en variaties in PSTVd. Daarnaast is gekeken hoe met deze kennis een eerste aanzet is te geven over hoe met Dahlia moet worden omgegaan om verspreiding van dit viroïde in Dahlia te voorkomen. Verspreiding in andere gewassen vindt vooral plaats via vegetatieve vermeerdering en overdracht van sap. Dit lijkt ook voor Dahlia van belang. Bij andere gewassen zoals aardappel en/of tomaat is ook verspreiding via stuifmeel, zaad en luizen, soms onder specifieke omstandigheden, waargenomen. Deze aspecten lijken in eerste instantie voor Dahlia minder van belang.
    Prion disease tempo determined by host-dependent substrate reduction
    Mays, C.E. ; Kim, C. ; Haldiman, T. ; Merwe, J. v.d.; Lau, A. ; Yang, J. ; Grams, J. ; Bari, M.A. Di; Nonno, R. ; Telling, G.C. ; Kong, Q. ; Langeveld, J.P.M. ; McKenzie, D. ; Westaway, D. ; Safar, J.G. - \ 2014
    The Journal of Clinical Investigation 124 (2014)2. - ISSN 0021-9738 - p. 847 - 858.
    chronic wasting disease - transgenic mice - cyclic amplification - cultured-cells - sheep scrapie - prpsc levels - protein - propagation - immunoassay - strains
    The symptoms of prion infection can take years or decades to manifest following the initial exposure. Molecular markers of prion disease include accumulation of the misfolded prion protein (PrPSc), which is derived from its cellular precursor (PrPC), as well as downregulation of the PrP-like Shadoo (Sho) glycoprotein. Given the overlapping cellular environments for PrPC and Sho, we inferred that PrPC levels might also be altered as part of a host response during prion infection. Using rodent models, we found that, in addition to changes in PrPC glycosylation and proteolytic processing, net reductions in PrPC occur in a wide range of prion diseases, including sheep scrapie, human Creutzfeldt-Jakob disease, and cervid chronic wasting disease. The reduction in PrPC results in decreased prion replication, as measured by the protein misfolding cyclic amplification technique for generating PrPSc in vitro. While PrPC downregulation is not discernible in animals with unusually short incubation periods and high PrPC expression, slowly evolving prion infections exhibit downregulation of the PrPC substrate required for new PrPSc synthesis and as a receptor for pathogenic signaling. Our data reveal PrPC downregulation as a previously unappreciated element of disease pathogenesis that defines the extensive, presymptomatic period for many prion strains
    Extensive literature search on cropping practices of host plants of some harmful organisms listed in Annex II A II of Directive 2000/29/EC
    Derkx, M.P.M. ; Brouwer, J.H.D. ; Breda, P.J.M. van; Heijerman-Peppelman, G. ; Heijne, B. ; Hop, M.E.C.M. ; Wubben, C.F.M. - \ 2014
    Parma, It. : EFSA (EFSA supporting publication 2014:EN-600) - 118
    fruitgewassen - vruchtbomen - hopbellen - teeltsystemen - teelt - gewasbescherming - plantenvermeerdering - landen van de europese unie - literatuuroverzichten - fruit crops - fruit trees - hops - cropping systems - cultivation - plant protection - propagation - european union countries - literature reviews
    The European Commission is currently seeking advice from EFSA (Mandate M-2012-0272) to assess for Arabis mosaic virus, Raspberry ringspot virus, Strawberry latent ringspot virus, Tomato black ring virus, Strawberry mild yellow edge virus, Strawberry crinkle virus, Daktulosphaira vitifoliae, Eutetranychus orientalis, Parasaissetia nigra, Clavibacter michiganensis spp. michiganensis, Xanthomonas campestris pv. vesicatoria, Didymella ligulicola and Phytophthora fragariae the risk to plant health for the EU territory and to evaluate the effectiveness of risk reduction options in reducing the level of risk. In addition, the Panel is requested to provide an opinion on the effectiveness of the present EU requirements against these organisms laid down in Council Directive 2000/29/EC. As a consequence EFSA needs insight in the cropping practices of Citrus spp., Fragaria x ananassa, Ribes spp., Rubus spp., Vaccinium spp., Humulus lupulus, Vitis vinifera, Prunus armeniaca, P. avium, P. cerasus, P. domestica and P. persica, which are host plants for these pests. An extensive and systematic literature search was done in which scientific and grey/technical literature was retrieved from the 28 EU Member States, Iceland and Norway. All references were stored in EndNote libraries, separately for scientific literature and grey/technical literature. For each reference information is provided on the source/search strategy, the crop, the country, the topic (cropping practice, propagation, protection or irrigation (only for Citrus)) and protected cultivation vs. field production. Yields of references depended on the crop and on the country. Over 27,000 references were provided to EFSA. This allows EFSA to quickly find information on crop production, both indoors and outdoors, of all crops that were studied in this extensive literature search. The data can be used by EFSA for the present mandate, but are also an excellent basis for other current and future mandates.
    'Aansluiting plug en substraat geeft wortelproblemen miltonia': Onderzoeker: opkweekmateriaal zuigt vocht aan (interview met Chris Blok)
    Velden, P. van; Blok, C. - \ 2014
    Onder Glas 11 (2014)4. - p. 27 - 27.
    glastuinbouw - miltonia - plantmateriaal - plantenvermeerdering - landbouwkundig onderzoek - plantenziekten - potplanten - greenhouse horticulture - miltonia - planting stock - propagation - agricultural research - plant diseases - pot plants
    Aanhoudende ziekteproblemen in het wortelmilieu waren voor miltoniatelers aanleiding om bij Wageningen UR Glastuinbouw aan de bel te trekken. Uit onderzoek blijkt dat het fijne materiaal waaruit een plug bestaat het water uit de bark trekt en vasthoudt. Daardoor blijven de wortels in de plug te lang nat.
    Pootgoedvermeerdering zetmeelaardappelen
    Wijnholds, K.H. ; Booij, J.A. - \ 2014
    aardappelen - akkerbouw - zetmeelgewassen - fabrieksaardappelen - vegetatieve vermeerdering - proeven op proefstations - vermeerderingsmateriaal - opbrengst - plantenvermeerdering - plantmateriaal - opslagkwaliteit - potatoes - arable farming - starch crops - starch potatoes - vegetative propagation - station tests - propagation materials - outturn - propagation - planting stock - storage quality
    In opdracht van Productschap Akkerbouw is onderzoek gedaan naar éénjarige rasvermeerdering van (TBM)-pootgoed. Afhankelijk van het perspectief van een ras voor de zetmeelteelt en de beschikbaarheid van pootgoed bij de kweekbedrijven, is er elk jaar in de periode 2008 tot en met 2012 een rasvermeerdering met verschillende rassen aangelegd op de PPO-locaties Kooijenburg of ‘t Kompas
    Zonder transport staat alles stil, ook in weefselkweek : oplossing ligt in bevordering verdamping
    Klerk, G.J.M. de; Kierkels, T. ; Heuvelink, E. - \ 2013
    Onder Glas 10 (2013)9. - p. 18 - 19.
    glastuinbouw - plantenvermeerdering - weefselkweek - kweektechnieken - in vitro kweek - transpiratie - tca - plantenontwikkeling - greenhouse horticulture - propagation - tissue culture - culture techniques - in vitro culture - transpiration - tca - plant development
    Nuchter beschouwd is het opmerkelijk dat planten in staat zijn in kweekbuizen te groeien. Het is daarom niet verwonderlijk dat zich regelmatig problemen voordoen. De oplossing daarvan is van groot belang voor de praktijk. Dat maakt snelle vermeerdering door weefselkweek voor veel meer gewassen toegankelijk.
    De Es mag niet weg! Onderzoek essenresistentie: nu sector en gebruiker aan zet
    Raats, S. ; Kuik, A.J. van; Hiemstra, J.A. - \ 2013
    Boom in business 2013 (2013)7. - ISSN 2211-9884 - p. 22 - 24.
    fraxinus - straatbomen - genetische bronnen van plantensoorten - rassen (planten) - cultivars - klonen - plantenvermeerdering - boomkwekerijen - resistentie van variëteiten - plantenziekten - chalara fraxinea - fraxinus - street trees - plant genetic resources - varieties - cultivars - clones - propagation - forest nurseries - varietal resistance - plant diseases - chalara fraxinea
    Op de Nederlandse Boominfodag 2012 maakte Jitze Kopinga bekend dat het WUR-CGN (Het Centrum voor Genetische Bronnen Nederland) een aantal redelijk resistente essenklonen bezit en dat de Wageningen Universiteit deze klonen vrijgeeft voor vermeerdering door kwekers. In november bezocht Kopinga in Vilnius een Europese projectbijeenkomst op het gebied van onderzoek naar essentaksterfte. Alle belangrijke onderzoekers in Europa waren daar aanwezig. Als het aan Kopinga ligt, overleeft de es met verve.'Maar dan moeten de sector en de gebruikers wel inzetten op vertrouwen', aldus de onderzoeker.
    Atmospheric blocking in a high resolution climate model: influences of mean state, orography and eddy forcing
    Berckmans, J.N.J. ; Woollings, T. ; Demory, M. ; Vidale, P. ; Roberts, M. - \ 2013
    Atmospheric Science Letters 14 (2013)1. - ISSN 1530-261X - p. 34 - 40.
    eddies - flow - propagation - simulations - patterns - project
    An underestimate of atmospheric blocking occurrence is a well-known limitation of many climate models. This article presents an analysis of Northern Hemisphere winter blocking in an atmospheric model with increased horizontal resolution. European blocking frequency increases with model resolution, and this results from an improvement in the atmospheric patterns of variability as well as a simple improvement in the mean state. There is some evidence that the transient eddy momentum forcing of European blocks is increased at high resolution, which could account for this. However, it is also shown that the increase in resolution of the orography is needed to realise the improvement in blocking, consistent with the increase in height of the Rocky Mountains acting to increase the tilt of the Atlantic jet stream and giving higher mean geopotential heights over northern Europe. Blocking frequencies in the Pacific sector are also increased with atmospheric resolution, but in this case the improvement in orography actually leads to a decrease in blocking
    River flow controls on tides an tide-mean water level profiles in a tidel freshwater river
    Sassi, M.G. ; Hoitink, A.J.F. - \ 2013
    Journal of Geophysical Research: Oceans 118 (2013)9. - ISSN 2169-9275 - p. 4139 - 4151.
    wavelet transform - salmonid habitat - mahakam delta - discharge - propagation - estuaries - channels - friction - impacts - cycles
    [1] Tidal rivers feature oscillatory and steady gradients in the water surface, controlled by interactions between river flow and tides. The river discharge attenuates the tidal motion, and tidal motion increases tidal-mean friction in the river, which may act as a barrier to the river discharge. Time series of tidal water level amplitudes at five gauge stations along the River Mahakam in Indonesia, and tidal flow velocity amplitudes at a discharge monitoring station were obtained applying wavelet analysis. Temporal variations in tidal damping coefficients for quaterdiurnal, semidiurnal, and diurnal tidal species were quantified from the observed amplitude profiles. The analysis shows that tidal damping during the rising limb of a discharge wave differs from damping during the falling limb. Wavelet cross-correlations between surface levels yielded empirical estimates of wave numbers. An empirical relation between tidal damping and river flow is derived to describe subtidal bottom friction along an idealized tidal river resembling the Mahakam. The subtidal friction is decomposed into contributions from the river flow only, from river-tide interaction, and from tidal asymmetry. Even for high river flow and low tidal velocity, river flow enhances friction attributed to river-tide interaction, causing subtidal water level setup. A simple multilinear regression model using subtidal bottom friction is employed to predict subtidal water levels at locations upstream, with a relatively good agreement between predictions and observations. The explicit expression shows the nonlinear dependence of subtidal friction on river flow velocity, explaining the complex behavior of tidal-mean surface level profiles.
    Hydrological drought across the world: impact of climate and physical catchment structure
    Lanen, H.A.J. van; Wanders, N. ; Tallaksen, L.M. ; Loon, A.F. van - \ 2013
    Hydrology and Earth System Sciences 17 (2013)5. - ISSN 1027-5606 - p. 1715 - 1732.
    water availability - european runoff - united-states - groundwater - flow - model - simulations - trends - classification - propagation
    Large-scale hydrological drought studies have demonstrated spatial and temporal patterns in observed trends, and considerable difference exists among global hydrological models in their ability to reproduce these patterns. In this study a controlled modeling experiment has been set up to systematically explore the role of climate and physical catchment structure (soils and groundwater systems) to better understand underlying drought-generating mechanisms. Daily climate data (1958-2001) of 1495 grid cells across the world were selected that represent Koppen-Geiger major climate types. These data were fed into a conceptual hydrological model. Nine realizations of physical catchment structure were defined for each grid cell, i.e., three soils with different soil moisture supply capacity and three groundwater systems (quickly, intermediately and slowly responding). Hydrological drought characteristics (number, duration and standardized deficit volume) were identified from time series of daily discharge. Summary statistics showed that the equatorial and temperate climate types (A-and C-climates) had about twice as many drought events as the arid and polar types (B-and E-climates), and the durations of more extreme droughts were about half the length. Selected soils under permanent grassland were found to have a minor effect on hydrological drought characteristics, whereas groundwater systems had major impact. Groundwater systems strongly controlled the hydrological drought characteristics of all climate types, but particularly those of the wetter A-, C-and D-climates because of higher recharge. The median number of droughts for quickly responding groundwater systems was about three times higher than for slowly responding systems. Groundwater systems substantially affected the duration, particularly of the more extreme drought events. Bivariate probability distributions of drought duration and standardized deficit for combinations of Koppen-Geiger climate, soil and groundwater system showed that the responsiveness of the groundwater system is as important as climate for hydrological drought development. This urges for an improvement of subsurface modules in global hydrological models to be more useful for water resources assessments. A foreseen higher spatial resolution in large-scale models would enable a better hydrogeological parameterization and thus inclusion of lateral flow.
    Geen last van onverenigbaarheid : aantal kwekers specialiseert zich in bomen op eigen wortel (interview met J. Hiemstra en B.J. van der Sluis)
    Doorn, J. van; Hiemstra, J.A. ; Sluis, B.J. van der - \ 2013
    Boom in business 4 (2013)1. - ISSN 2211-9884 - p. 46 - 50.
    boomteelt - stekken - vermeerderingsmateriaal - plantenvermeerdering - oculeren - straatbomen - wortelstekken - arboriculture - cuttings - propagation materials - propagation - budding - street trees - root cuttings
    Een aantal laanboomkwekerijen in Nederland specialiseert zich steeds meer in het kweken van bomen op eigen wortel. Voordeel is dat er nooit onverenigbaarheid kan optreden en er minder of geen sprake is van opslag aan de onderstam. Ook de vraag van afnemers naar bomen op eigen wortel groeit. Wel is het bij stekken belangrijk dat een voldoende fijn vertakt en gelijkmatig wortelstelsel wordt ontwikkeld.
    Probabilistic analysis of hydrological drought characteristics using meteorological drought
    Wong, G. ; Lanen, H.A.J. van; Torfs, P.J.J.F. - \ 2013
    Hydrological Sciences Journal 58 (2013)2. - ISSN 0262-6667 - p. 253 - 270.
    frequency-analysis - streamflow droughts - severity - copulas - duration - europe - river - propagation - groundwater - risk
    Droughts are an inevitable consequence of climate variability and are pervasive across many regions. Their effects can vary on an extensive scale, depending on the type of drought and people’s vulnerability. Crucial characteristics of both hydrological (groundwater, streamflow) and meteorological (precipitation) droughts are related to their durations and severities, and these characteristics are typically correlated. While many studies have addressed the dependencies between these characteristics for either the meteorological or hydrological drought, the cross-dependence between meteorological and hydrological drought characteristics is barely investigated. The development of meteorological drought characteristics to hydrological drought characteristics is often hard to model and their connection is not definitively established. In order to better understand and explain this relationship, this study seeks to apply statistical tools and models. Drought characteristics data from areas in Europe with different climates are analysed. Two approaches of identifying related meteorological and hydrological drought are explored and compared. Classical linear correlation techniques do not provide promising results, indicating that any statistic of a hydrological drought is not a straightforward function of a preceding meteorological drought. Subsequently, the application of the concept of copulas to explore this dependence between meteorological and hydrological drought characteristics is investigated. The more comprehensive approach of copulas shows that the meteorological drought contains probability information of the successive hydrological drought.
    Verbetering weefselkweek met pilotgewas Alstroemeria
    Klerk, G.J.M. de - \ 2012
    Plant Breeding Wageningen UR : Wageningen - 31
    alstroemeria - plantenvermeerdering - weefselkweek - landbouwkundig onderzoek - plantenontwikkeling - apicale dominantie - groei - optimalisatiemethoden - alstroemeria - propagation - tissue culture - agricultural research - plant development - apical dominance - growth - optimization methods
    Alstroemeria is een van de siergewassen die op grote schaal in weefselkweek vermeerderd wordt. Vergeleken met andere in vitro vermeerderde gewassen is de vermeerdering echter onder de maat. Paweena Pumisutapon deed promotieonderzoek van april 2007 tot eind 2011 vanuit twee invalshoeken om de vermeerdering te verbeteren: verbetering van de groei (=gewichtstoename) van de rizomen en stimulering van de uitgroei van okselknoppen. In dit verslag wordt het promotieonderzoek van Paweena Pumisutapon samengevat.
    A systematic and extensive literature search on crop production of host plants of seven organisms harmful to horticulture
    Derkx, M.P.M. ; Brouwer, J.H.D. ; Breda, P.J.M. van; Helm, F.P.M. van der; Hop, M.E.C.M. ; Landzaat, K.M. ; Wubben, C.F.M. - \ 2012
    Wageningen : Wageningen UR/DLO - 85
    tuinbouwgewassen - veldgewassen - teelt onder bescherming - gewasproductie - landbouwplantenteelt - teeltsystemen - teelt - plantenvermeerdering - gewasbescherming - landen van de europese unie - horticultural crops - field crops - protected cultivation - crop production - crop husbandry - cropping systems - cultivation - propagation - plant protection - european union countries
    The European Commission is currently seeking advice from EFSA, on the risk to plant health for the EU territory including the evaluation of the effectiveness of risk reduction options of seven organisms harmful to horticulture (both food- and non food) plants: Liriomyza trifolii, Liriomyza huidobrensis, Erwinia chrysanthemi pv. dianthicola (updated taxonomic name: Dickeya dianthicola), Pseudomonas caryophylli (updated taxonomic name: Burkholderia caryophylli). Phialophora cinerescens, Puccinia horiana and Chrysanthemum stunt viroid. In addition, the Plant Health Panel is requested to provide an opinion on the effectiveness of the present EU requirements against those organisms laid down in the Council Directive 2000/29/EC. As a preparatory work for the scientific opinions an extensive and systematic literature search was done on crop production practices of 21 food- and non-food crops that are host crops of these seven harmful organisms. This search resulted in nearly 20,000 relevant references, which were grouped per crop and per EU Member State. All references are stored in two EndNote files, one with scientific literature, retrieved from CAB Abstracts and Scopus and one with technical/grey literature, retrieved from AGRIS, ARTIK and website searches from stakeholder associations, extension services, national/regional authorities and national libraries. Each reference in the EndNote files has a label (cropping practice, propagation or protection). Moreover, information is provided on protected cultivation/field production. The storage of all references in EndNote files, in which each reference is accompanied by the name of the crop, the country, the label (cropping practice, propagation and protection), the search strategy/source) and information on protected cultivation/field production allows EFSA to quickly find information on crop production, both indoors and outdoors, of the 21 food- and non-food crops that were studied in this extensive literature survey. These data can be used by EFSA for the present mandate, but are also an excellent basis for other current and future mandates.
    Check title to add to marked list
    << previous | next >>

    Show 20 50 100 records per page

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