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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    Identification of bioactive phytochemicals in mulberries
    D’urso, Gilda ; Mes, Jurriaan J. ; Montoro, Paola ; Hall, Robert D. ; Vos, Ric C.H. de - \ 2020
    Metabolites 10 (2020)1. - ISSN 2218-1989
    Antioxidant activity - High resolution mass spectrometry - In vitro gastrointestinal digestion - Mulberry - α-glucosidase inhibitory activity

    Mulberries are consumed either freshly or as processed fruits and are traditionally used to tackle several diseases, especially type II diabetes. Here, we investigated the metabolite compositions of ripe fruits of both white (Morus alba) and black (Morus nigra) mulberries, using reversed-phase HPLC coupled to high resolution mass spectrometry (LC-MS), and related these to their in vitro antioxidant and α-glucosidase inhibitory activities. Based on accurate masses, fragmentation data, UV/Vis light absorbance spectra and retention times, 35 metabolites, mainly comprising phenolic compounds and amino sugar acids, were identified. While the antioxidant activity was highest in M. nigra, the α-glucosidase inhibitory activities were similar between species. Both bioactivities were mostly resistant to in vitro gastrointestinal digestion. To identify the bioactive compounds, we combined LC-MS with 96-well-format fractionation followed by testing the individual fractions for α-glucosidase inhibition, while compounds responsible for the antioxidant activity were identified using HPLC with an online antioxidant detection system. We thus determined iminosugars and phenolic compounds in both M. alba and M. nigra, and anthocyanins in M. nigra as being the key α-glucosidase inhibitors, while anthocyanins in M. nigra and both phenylpropanoids and flavonols in M. alba were identified as key antioxidants in their ripe berries.

    Knockdown of MLO genes reduces susceptibility to powdery mildew in grapevine
    Pessina, Stefano ; Lenzi, Luisa ; Perazzolli, Michele ; Campa, Manuela ; Costa, Lorenza Dalla; Urso, Simona ; Valè, Giampiero ; Salamini, Francesco ; Velasco, Riccardo ; Malnoy, Mickael - \ 2016
    Horticulture Research 3 (2016). - ISSN 2052-7276
    Erysiphe necator is the causal agent of powdery mildew (PM), one of the most destructive diseases of grapevine. PM is controlled by sulfur-based and synthetic fungicides, which every year are dispersed into the environment. This is why PM-resistant varieties should become a priority for sustainable grapevine and wine production. PM resistance can be achieved in other crops by knocking out susceptibility S-genes, such as those residing at genetic loci known as MLO (Mildew Locus O). All MLO S-genes of dicots belong to the phylogenetic clade V, including grapevine genes VvMLO7, 11 and 13, which are upregulated during PM infection, and VvMLO6, which is not upregulated. Before adopting a gene-editing approach to knockout candidate S-genes, the evidence that loss of function of MLO genes can reduce PM susceptibility is necessary. This paper reports the knockdown through RNA interference of VvMLO6, 7, 11 and 13. The knockdown of VvMLO6, 11 and 13 did not decrease PM severity, whereas the knockdown of VvMLO7 in combination with VvMLO6 and VvMLO11 reduced PM severity up to 77%. The knockdown of VvMLO7 and VvMLO6 seemed to be important for PM resistance, whereas a role for VvMLO11 does not seem likely. Cell wall appositions (papillae) were present in both resistant and susceptible lines in response to PM attack. Thirteen genes involved in defense were less upregulated in infected mlo plants, highlighting the early mlo-dependent disruption of PM invasion.
    Optimal land use/cover classification using remote sensing imagery for hydrological modelling in a Himalayan watershed
    Sameer Saran, ; Sterk, G. ; Kumar, S. - \ 2007
    In: Remote sensing for agriculture, ecosystems, and hydrology VII. - Firenze/itlay : SPIE - ISBN 9780819469007 - p. 67420N - 1-6720N-10.
    Land use/cover is an important watershed surface characteristic that affects surface runoff and erosion. Many of the available hydrological models divide the watershed into Hydrological Response Units (HRU), which are spatial units with expected similar hydrological behaviours. The division into HRU's requires good-quality spatial data on land use/cover. This paper presents different approaches to attain an optimal land use/cover map based on remote sensing imagery for a Himalayan watershed in northern India. First digital classifications using maximum likelihood classifier (MLC) and a decision tree classifier were applied. The results obtained from the decision tree were better and even improved after post classification sorting. But the obtained land use/cover map was not sufficient for the delineation of HRUs, since the agricultural land use/cover class did not discriminate between the two major crops in the area i.e. paddy and maize. Therefore we adopted a visual classification approach using optical data alone and also fused with ENVISAT ASAR data. This second step with detailed classification system resulted into better classification accuracy within the 'agricultural land' class which will be further combined with topography and soil type to derive HRU's for physically-based hydrological modelling.
    Changes in the fermentation end-product profile in the GIT of piglets during post-colostrum suckling period
    Awati, A. ; Urso, S. D'; Williams, B.A. ; Bosch, M. ; Verstegen, M.W.A. - \ 2007
    Livestock Science 108 (2007)1-3. - ISSN 1871-1413 - p. 156 - 158.
    Pre-weaning development of microbial activity has an effect on post-weaning establishment of the gastro-intestinal tract (GIT) microbiota. An in vivo study was conducted, to evaluate the effect of age on fermentation end-product profiles during the post-colostrum suckling period, as the variation in composition of mature milk is minimum. Sixteen piglets from two litters (eight per litter) were selected. During the study, piglets had free access to sow's milk, but no creep feed, nor antibiotic treatments. Two piglets from each litter were sacrificed on d 11, 18, 25 and 32 of age. The digesta samples were collected from the beginning and end of the small intestine, caecum and colon. Samples were analyzed for fermentation end-product concentrations. Combining the results from all the GIT sites, it was observed that, total VFA concentration increased with age of the piglets. There was a significant rise in acetic acid concentrations, with a significant decrease in lactic acid concentrations from d11 to d32, while the proportions of SCFA, (acetic acid 72%, propionic acid 15% and butyric acid 6% of total VFA) and ammonia concentrations remained unchanged. These results clearly suggest that, the microbial activity in terms of fermentation end-product profile skewed from lactic acid to acetic acid as a major product during the post-colostrum suckling period. This may be attributed to lower substrate availability due to increased number of microbes or increased diversity in the microbiota in time.
    Fluorescence explorer (FLEX): An optimised payload to map vegetation photosynthesis from space
    Moreno, J.F. ; Asner, G.P. ; Bach, H. ; Belenguer, T. ; Bell, A. ; Buschmann, C. ; Calera, A. ; Calpe, J. ; Campbell, P. ; Cecchi, G. ; Colombo, R. ; Corp, L.A. ; Court, A. ; Cutter, M.A. ; Disney, M. ; Dudelzak, A. ; Urso, G. D'; Fernandes, R. ; Flexas, J. ; Gege, P. ; Gielen, B. ; Gitelson, A. ; Gloor, E.U. ; Gower, J. ; Green, R.O. ; Hill, J. ; Jacquemoud, S. ; Jia, L. ; Kneubühler, M. ; Laurila, T. ; Lewis, P. ; Lobb, D. ; Magnani, F. ; Maier, S.W. ; Martinez, A. ; Marek, M.V. ; Martinez Cobo, P. ; Mazzinghi, P. ; Menenti, M. ; Merton, R. ; Middleton, E. ; Miguel, E. De; Miller, J. ; Mohammed, G. ; Milton, E.J. ; Morales, F. ; Moya, I. ; Nedbal, L. ; Knorr, W. ; Ottle, C. ; Olioso, A. ; Pace, S. ; Palucci, A. ; Pedros, R. ; Peltoniemi, J. ; Penuelas, J. ; Plaza, A.J. ; Polcher, J. ; Rascher, U. ; Reuter, R. ; Rosema, A. ; Roujean, J.L. ; Saito, Y. ; Saugier, B. ; Schaepman, M.E. ; Serrano, J.B. ; Settle, J.J. ; Sierra, M. ; Sobrino, J. ; Stoll, M.P. ; Su, Z. ; Tobehn, C. ; Tremblay, N. ; Valcke, R. ; Verhoef, W. ; Veroustraete, F. ; Verstraete, M. ; Zarco Tejada, P. - \ 2006
    In: Proceedings AIAA 57th International Astronautical Congress, 2 - 6 October, 2006, Valencia, Spain. - Valencia : AIAA - p. 2065 - 2074.
    Changes in the fermentation end product profile in the GIT of piglets during post-colostrum suckling period
    Awati, A. ; Urso, S. D'; Williams, B.A. ; Bosch, M.W. ; Verstegen, M.W.A. - \ 2006
    Possibilities of MERIS for sub-pixel regional land cover mapping
    Zurita Milla, R. ; Schaepman, M.E. ; Clevers, J.G.P.W. - \ 2005
    In: Proceedings SPIE - Remote Sensing for Agriculture, Ecosystems, and Hydrology VII, Brugge 2005. - Bruges : SPIE - p. 264 - 273.
    The Medium Resolution Imaging Spectrometer, MERIS, on board of ENVISAT-1 fulfils the information gap between the current high and low spatial resolution sensors. In this respect, the use of MERIS full resolution data (300 m pixel size) has a great potential for regional and global land cover mapping. However, the spectral and temporal resolutions of MERIS (15 narrow bands and a revisit time of 2-3 days, respectively) might be further exploited in order to get land cover information at a more detailed scale. The performance of MERIS for extracting sub-pixel land cover information was evaluated in this study. An iterative linear spectral unmixing method designed to optimize the number of endmembers per pixel was used to classify 2 MERIS full resolution images acquired over The Netherlands. The latest version of the Dutch land use database, the LGN5, was used as a reference dataset both for the validation and for the selection of the endmembers. This dataset was first thematically aggregated to the main 9 land cover types and then spatially aggregated from its original 25m to 300m. Because the fractions of the different land cover types present in each MERIS pixel were computed during the aggregation, a sub-pixel accuracy assessment could be done (in addition to the traditional assessment based on a hard classification). Results pointed out that MERIS has a great potential for providing sub-pixel land cover information because the classification accuracies were up to 60%. The correct number of endmembers to unmix every pixel was adequately identified by the iterative linear spectral unmixing. Future research efforts should be put in making use of the high revisit time of the MERIS sensor (temporal unmixing).
    Water management through indicators of water costs, price and value: an agro-hydrological modeling framework
    Urso, G. D'; Stanghellini, C. - \ 2003
    In: Proceedings of the Workshop on: "Managing water demand in agriculture through pricing: research issues and lessons learned" CNR-ISAFOM - p. 273 - 282.
    Effects of nitrogen stress in grass swards on evolution of ground cover and spectral characteristics of leaf strata
    Schut, A.G.T. ; Ketelaars, J.J.M.H. - \ 2001
    In: Remote sensing for agriculture, ecosystems, and hydrology III : 8th International Symposium on remote sensing 2001, Toulouse, France / M. Owe and G. D'Urso. - [S.l.] : [s.n.], 2001 - p. 191 - 198.
    Simulation and management of on-demand irrigation systems: a combined agrohydrological and remote sensing approach
    Urso, G. D' - \ 2001
    Wageningen University. Promotor(en): R.A. Feddes; M. Menenti. - S.l. : S.n. - ISBN 9789058083999 - 173
    irrigatie - waterbeheer - watervoorziening - evapotranspiratie - modellen - remote sensing - bodemwatergehalte - agrohydrologie - geo-informatie - simulatiemodel - Italië - irrigation - water management - water supply - evapotranspiration - soil water content - models - remote sensing

    Rational use of water resources in agriculture requires improvements in the efficiency of irrigation. Many irrigation systems, particularly in Mediterranean regions, have been enhanced by replacing open channel conveyance systems with pressurised pipelines. This allows to provide water on-demand. Increased demand of water for civil and industrial uses and a progressive reduction of available water resources compel a more efficient use of irrigation water. To achieve this goal irrigation managers need to understand and to monitor the processes which determine the operation of an irrigation system.

    In this thesis a procedure integrating the agrohydrological aspects of irrigation with hydraulic and management aspects has been developed. The procedure named SIMODIS (SImulation and Management of On-Demand Irrigation Systems) is based on the integration of different tools such as agrohydrological and hydraulic simulation models, remote sensing and GIS techniques.

    An irrigation system is described as a set of elementary (e.g. individual fields) connected by the pressurised conveyance system. The spatial distribution of soil water deficit in each elementary unit is computed daily by combining the soil water model SWAP with occasional satellite-based estimates of crop water requirements. A methodology has been developed to obtain spatially distributed input data for the soil water model SWAP i.e. the soil hydraulic properties and the upper and lower boundary conditions.

    Multispectral satellite images are used to map the crop coefficients needed for the definition of the SWAP upper boundary condition in each elementary unit of the irrigation district. Two different approaches have been proposed. The first is based on classification techniques, where clustering algorithms are applied to derive the spectral classes corresponding to different crop coefficient values. In the second approach, the crop coefficient is analytically related to the canopy variables determining the potential evapotranspiration i.e. leaf area index, surface albedo and crop height. At-surface directional spectral reflectance are used to estimate these canopy variables from which the value of crop coefficient is calculated.

    The spatial distribution of farmers' water demand is derived on a daily basis from the soil water deficit according to predefined irrigation scheduling criteria. Before applying this farmers' water demand distribution for the given day, the SIMODIS procedure assess whether water demand is consistent with the available amount of water resources and with the structural and operational constraints imposed by the conveyance and distribution system. For this purpose a steady-state simulation model of pipeline hydraulics is used in SIMODIS. The final distribution of farmers' water demand is then resulting from a three-tiered adaptation of irrigation schedule considering: i) the limitation of flow rate at delivery outlets, ii) the limitation of available water resources, iii) the required minimum hydraulic head at the delivery outlets.

    The procedure SIMODIS has been applied in the Gromola irrigation district of approximately 3000 ha in southern Italy. Measurements of irrigation volumes were used to identify the parameters driving irrigation scheduling. Irrigation efficiency indicators were calculated from the spatial distribution of actual transpiration rates and of the corresponding irrigation volumes applied. To illustrate the use of SIMODIS in support of irrigation decision making, alternative scenarios of water management were simulated and compared.

    The development of SIMODIS demonstrated that agrohydrological simulation models and remote sensing can be effectively combined to describe the operation of an irrigation system. These techniques have reached a sufficient degree of reliability to be transferred to practical applications. The estimation of crop coefficients by means of remote sensing techniques is of general usefulness in the definition of the upper boundary condition of distributed hydrological simulation models and it can be applied to evaluate with satisfactory accuracy the crop water requirements at regional scale. In the future new types of satellite sensors will probably allow for a more precise determination of the canopy variables, thus providing novel opportunities in the integration between agrohydrological simulation models and remote sensing techniques.

    Regional application of one-dimensional water flow models for irrigation management
    Urso, G. D'; Menenti, M. ; Santini, A. - \ 1999
    Agricultural Water Management 40 (1999)2/3. - ISSN 0378-3774 - p. 291 - 302.
    Numerical models for the simulation of soil water processes can be used to evaluate the spatial and temporal variations of crop water requirements; this information can support the irrigation management in a rationale usage of water resources. This latter objective requires the knowledge of spatially distributed input parameters concerning vegetation status, soil hydraulic behaviour and groundwater interaction. This task can be achieved by a conjunctive use of remote sensing techniques, geographical information systems and hydrological simulation models. The present work focuses on the criteria applied for the implementation of a one-dimensional model for water flow in each parcel of an irrigation district in southern Italy having extension of 3000 ha.
    Remote sensing, GIS and hydrological modelling for irrigation management
    Menenti, M. ; Azzali, S. ; Urso, G. d' - \ 1996
    In: Sustainability of irrigated agriculture / Pereira, L.S., Feddes, R.A., Gilley, J.R., Lesaffre, B., - p. 453 - 472.
    This paper gives an overview of literature and of work done by the authors between 1988 and 1993. It was presented at a NATO expert meeting on sustainability of irrigated agriculture in 1994. The paper deals with crop water requirements and crop waterstress, assessing irrigation performance with satellite data, monitoring drainage conditions and salt-affected areas, distributed hydrological models of irrigation schemes, water allocation on the basis of farmers' preferences, and management issues.
    Remote sensing and simulation modelling for on-demand irrigation systems management
    Urso, G. D'; Menenti, M. ; Santini, A. - \ 1996
    In: Irrigation scheduling: from theory to practice / Smith, M., Pereira, L.S., Berengena, J., Itier, B., Goussard, J., Ragab, R., Tollefson, L., van Hofwegen, P., - p. 305 - 312.
    This paper describes a procedure for monitoring and improving the performance of on-demand irrigation networks, based on the integration of remote sensing techniques and simulation modelling of water flow in each component of the system. In order to adequately reproduce the actual operation of an on-demand irrigation system, the physical characteristics of the irrigation systems (crop, soil and distribution network) are linked to the farmers' irrigation criteria and preferences. The development of this procedure, which is currently being implemented in a district in South Italy, is of great support to improving the management and monitoring of irrigation systems.
    Performance indicators for the statistical evaluation of digital image classifications
    Urso, G. D'; Menenti, M. - \ 1996
    ISPRS Journal of Photogrammetry and Remote Sensing 51 (1996)2. - ISSN 0924-2716 - p. 78 - 90.
    uitrusting - afbeelden - fotointerpretatie - remote sensing - equipment - imagery - photointerpretation - remote sensing
    A statistical procedure is proposed to evaluate the algorithms for the numerical classification of images. The approach is based on the derivation of performance indicators from measurements of signature separability and thresholding analysis. Although these measurements are not new in image processing techniques, they are used in this study in an original way for the comparison of outputs resulting from different classification criteria. The theoretical description of the method suggested is followed by its practical application to a case-study for mapping crop coefficients in an irrigation district.
    Management of irrigation schemes in arid countries
    Menenti, M. ; Azzali, S. ; Urso, G. d' - \ 1995
    In: Use of remote sensing techniques in irrigation and drainage; proceedings of the expert consultation, Montpellier, France, 2-4 November 1993. Rome, FAO, 1995. Water Rep. 4 - p. 81 - 98.
    The issue of the actual practical scope of remote sensing is to some extent a matter of unfulfilled promises in the early stage of remote sensing by satellites. A detailed analysis of irrigation management procedures should always come first. Once data requirements are defined in detail, the actual scope for using satellite data can be assessed and required data products specified in detail. Since such data requirements cannot be met with satellite data only, satellite data have to be merged with other data sets and a variety of calculation procedures must be applied.
    Remote sensing and simulation modeling for on-demand irrigation systems management
    Urso, G. D'; Menenti, M. ; Santini, A. - \ 1995
    In: ICID/FAO workshop; irrigation scheduling: from theory to practice. Rome, ICID, 1995, Background Doc. 16
    This paper describes a procedure for monitoring and improving the performance of on-demand irrigation networks, based on the integration of remote sensing techniques and simulation modelling of water flow in each component of the system. In order to adequately reproduce the actual operation of an on-demand irrigation system, the physical characteristics of the irrigation systems (crop, soil and distribution network) are linked to the farmers' irrigation criteria and preferences. The development of this procedure, which is currently being implemented in a district in South Italy, is of great support to improving the management and monitoring of irrigation systems.
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