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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Autonomous In-Row Navigation of an Orchard Robot with a 2D LIDAR Scanner and Particle Filter with a Laser-Beam Model
Blok, P.M. ; Suh, H.K. ; Boheemen, K. van; Kim, Hak-Jin ; Gookhwan, Kim - \ 2018
Journal of Institute of Control, Robotics and Systems 24 (2018)8. - ISSN 1976-5622 - p. 726 - 735.
In mountainous orchards, agricultural tasks, such as crop protection and harvesting, are characterized as being labor intensive and dangerous. An autonomous orchard robot that can execute these unattended seems a promising alternative to increase task operability. An essential function in the development of an autonomous orchard robot is navigation, which is usually based on tree-row detection from LIDAR scan data by using navigational algorithms. This research applies a probabilistic particle filter (PF) algorithm with a novel laser-beam model for the autonomous in-row navigation of an orchard robot. The navigational accuracy of the algorithm is assessed in a Dutch apple orchard over a distance of 500 m, with the robot driving at two velocities: 0.25 m/s and 0.50 m/s. At both speeds, almost 50% of the observed lateral deviations were lower than 0.05 m from the optimal navigation line. With the use of the PF algorithm, the robot navigated itself between six patterns of tree rows with artificially removed trees. Some lateral deviations exceeded 0.10 m when three adjacent trees were missing in both tree rows. Based on these results, a PF with a laser beam model is an accurate and robust algorithm for the autonomous in-row navigation in semi-structured outdoor environments, such as orchards.
Flexible 3D Nanoporous Graphene for Desalination and Bio-decontamination of Brackish Water via Asymmetric Capacitive Deionization
El-Deen, Ahmed G. ; Boom, Remko M. ; Kim, Hak Yong ; Duan, Hongwei ; Chan-Park, Mary B. ; Choi, Jae Hwan - \ 2016
ACS Applied Materials and Interfaces 8 (2016)38. - ISSN 1944-8244 - p. 25313 - 25325.
asymmetric capacitive deionization - nanohybrid electrode - nanoporous graphene - water desalination - water disinfection

Nanoporous graphene based materials are a promising nanostructured carbon for energy storage and electrosorption applications. We present a novel and facile strategy for fabrication of asymmetrically functionalized microporous activated graphene electrodes for high performance capacitive desalination and disinfection of brackish water. Briefly, thiocarbohydrazide coated silica nanoparticles intercalated graphene sheets are used as a sacrificial material for creating mesoporous graphene followed by alkaline activation process. This fabrication procedure meets the ideal desalination pore diameter with ultrahigh specific surface area ∼ 2680 m2 g-1 of activated 3D graphene based micropores. The obtained activated graphene electrode is modified by carboxymethyl cellulose as negative charge (COO-2) and disinfectant quaternary ammonium cellulose with positively charged polyatomic ions of the structure (NR4 +). Our novel asymmetric coated microporous activated 3D graphene employs nontoxic water-soluble binder which increases the surface wettability and decreases the interfacial resistance and moreover improves the electrode flexibility compared with organic binders. The desalination performance of the fabricated electrodes was evaluated by carrying out single pass mode experiment under various cell potentials with symmetric and asymmetric cells. The asymmetric charge coated microporous activated graphene exhibits exceptional electrosorption capacity of 18.43 mg g-1 at a flow rate of 20 mL min-1 upon applied cell potential of 1.4 V with initial NaCl concentration of 300 mg L-1, high charge efficiency, excellent recyclability, and, moreover, good antibacterial behavior. The present strategy provides a new avenue for producing ultrapure water via green capacitive deionization technology.

Effect of osmopriming on germination and initial growth of physalis angulata L. under salt stress and on expression of associated genes
Souza, Manuela Oliveira de; Pelacani, Claudinéia R. ; Willems, Leo A.J. ; Castro, Renato D. de; Hilhorst, Henk W.M. ; Ligterink, Wilco - \ 2016
Anais da Academia Brasileira de Ciencias 88 (2016)S1. - ISSN 0001-3765 - p. 503 - 516.
Germinability - RT-qPCR - Salinity - Seedling growth

This study aimed to evaluate the effects of priming on seed germination under salt stress and gene expression in seeds and seedlings of P. angulata L. After priming for 10 days, seed germination was tested in plastic trays containing 15 ml of water (0 dS m-1 - control) or 15 ml of NaCl solution (2, 4, 6, 8, 10, 12, 14 and 16 dS m-1). Fresh and dry weight of shoots and roots of seedlings were evaluated at 0, 2, 4, 6, 8 dS m-1. Total RNA was extracted from whole seeds and seedlings followed by RT-qPCR. The target genes selected for this study were: ascorbate peroxidase (APX), glutathione-S-transferase (GST), thioredoxin (TXN), high affinity potassium transporter protein 1 (HAK1) and salt overly sensitive 1 (SOS1). At an electroconductivity of 14 dS m-1 the primed seeds still germinated to 72%, in contrast with the non-primed seeds which did not germinate. The relative expression of APX was higher in primed seeds and this may have contributed to the maintenance of high germination in primed seeds at high salt concentrations. GST and TXN displayed increased transcript levels in shoots and roots of seedlings from primed seeds. Priming improved seed germination as well as salt tolerance and this is correlated with increased expression of APX in seeds and SOS1, GST and TXN in seedlings.

Analysis of inheritance mode in chrysanthemum using EST-derived SSR markers
Park, Sang Kun ; Arens, Paul ; Esselink, Danny ; Lim, Jin Hee ; Shin, Hak Ki - \ 2015
Scientia Horticulturae 192 (2015). - ISSN 0304-4238 - p. 80 - 88.
Allele dosage - Chrysanthemum x morifolium - Dendranthema x grandiflorum - Genotyping - Polyploidy - Segregation type

To study the inheritance mode of hexaploid chrysanthemum (random or preferential chromosome pairing), a segregation analysis was carried out using SSR markers derived from chrysanthemum ESTs in the public domain. A total of 248 EST-SSR primer pairs were screened in chrysanthemum cultivars 'Dancer' and 'Puma White', of which 49 EST-SSRs were selected as polymorphic and informative markers. These polymorphic markers were used for genotyping a F1-pseudo test cross population derived from a cross between these two cultivars. The 49 EST-SSRs detected 210 marker alleles with an average number of 4.29 marker alleles per locus. For 180 of these polymorphic SSR marker alleles, segregation could be estimated using a χ2 goodness of fit test (α=0.05) with the expected segregation ratios for hexasomic or disomic inheritance. For 65 SSR marker alleles the segregation ratio was informative for the type of inheritance, 33 marker alleles gave a good fit to the expected segregation ratio for hexasomic inheritance and whereas 24 marker alleles gave a good fit for disomic inheritance showing a higher number of marker alleles supporting autopolyploid segregation in chrysanthemum. In addition, the observed ratio of non-simplex to simplex markers was 20:80 (25 vs. 99) supported hexasomic inheritance. Furthermore, random marker allele assortment was found within the six fully informative markers giving conclusive evidence for hexasomic inheritance in chrysanthemum at these chromosomal regions.

Presentation of the Innovative Packaging Award: 'De Gouden Noot'
Omta, Onno - \ 2012
Verbetering ketenresultaat bruine bonen door beter uitgangsmateriaal
Timmer, R.D. - \ 2012
Kennisakker.nl 2012 (2012)4 mei.
vermeerderingsmateriaal - zaadkeuring - droge bonen - rassen (planten) - rassenproeven - vollegrondsgroenten - propagation materials - seed certification - dry beans - varieties - variety trials - field vegetables
Bij de teelt van bruine bonen worden in toenemende mate afwijkende planten in het veld aangetroffen. Dit is waarschijnlijk het gevolg van gebruik van eigen zaaizaad. De verwerkende industrie (HAK) constateert een teruglopende kwaliteit van de ingekochte bruine bonen, waardoor de continuïteit van deze keten in gevaar dreigt te komen. Zij verwacht deze dreiging door een verbetering van de zaaizaadkwaliteit te kunnen afwenden. In 2010 is geïnventariseerd welke rassen er momenteel beschikbaar zijn, en met deze rassen is in 2010 en 2011, met financiering van de Productschappen Akkerbouw en Tuinbouw, een rassenvergelijking uitgevoerd. Belangrijkste conclusie was dat de aloude rassen Berna en Narda nog steeds de voorkeur hebben bij de teelt van bruine bonen. De Narda wat betreft opbrengst en de Berna heeft een plusje wat betreft smaak en uiterlijk. Om kleurverschillen tussen bonen tegen te gaan, is het belangrijk bij deze rassen uit te gaan van gecertificeerd zaaizaad.
Verbetering ketenresultaat door beter uitgangsmateriaal bruine bonen
Timmer, R.D. - \ 2012
Lelystad : PPO AGV (PPO publikatie 487) - 15
rassenproeven - vermeerderingsmateriaal - droge bonen - zaadkeuring - rassen (planten) - vollegrondsgroenten - variety trials - propagation materials - dry beans - seed certification - varieties - field vegetables
Bij de teelt van bruine bonen worden in toenemende mate afwijkende planten in het veld aangetroffen. Dit is het gevolg van veelvuldig gebruik van eigen zaaizaad. Het gehele areaal aan bruine bonen in Nederland (1000-1500 ha) wordt met twee zeer oude rassen (Berna en Narda) ingezaaid. De teruglopende kwaliteit van de bruine bonen vormt een gevaar voor de teelt en de continuïteit van de keten. Door een verbetering van de zaaizaadkwaliteit is dit mogelijk af te wenden. In 2010 zijn hiertoe gesprekken gevoerd met verschillende ketenpartijen te weten telers (BBTB), collecterende handel (Termont & Thomaes) en verwerkende industrie (HAK). Ook is er een rassenproef uitgevoerd waarin verschillende rassen en zaaizaadpartijen zijn vergeleken. Het overleg met de ketenpartijen heeft ertoe geleid dat er afspraken zijn gemaakt over een verbetering van het uitgangsmateriaal voor de telers.
Insect Semiochemicals
Kogel, Willem Jan de - \ 2010
Streekhout – stookhout
Anonymous, - \ 2009
Wageningen : Wetenschapswinkel, Wageningen UR
landschapsbeheer - afvalhout - bio-energie - energiebronnen - economische haalbaarheid - haalbaarheidsstudies - biobased economy - landscape management - waste wood - bioenergy - energy sources - economic viability - feasibility studies
Projectbeschrijving. Drie agrarische natuurverenigingen (ANV's), verenigd in de koepelorganisatie Natuurlijk Platteland Oost (NPO), zijn samen met vijf Duitse 'Kreisen' betrokken bij het Eu-regioproject 'Stoken op Streekhout' dat in het najaar 2009 van start is gegaan. Doel van het project is het scheppen van voorwaarden om landschapsonderhoud en -ontwikkeling voor boeren economisch aantrekkelijker te maken door de benutting van hak- en snoeihout als energiebron in de eigen regio. Voor het EU-project hebben de ANV’s aan de Wetenschapswinkel van Wageningen UR gevraagd om het aanbod van hout te inventariseren in de hele Achterhoek en om onderzoek te doen naar de ontwikkeling van de potentiële vraag naar snoeihout en de marktstructuur waarin vraag en aanbod wordt afgestemd.
'Overleven remt innovatie in sector' : Landelijke Industriegroentendag op Proefboerderij Vredepeel
Schel, J. ; PPO Akkerbouw, Groene Ruimte en Vollegrondsgroente, - \ 2007
Nieuwe oogst / Magazine gewas 3 (2007)16. - ISSN 1871-093X - p. 18 - 19.
groenteteelt - industrie - innovaties - verbetering - kosten - vegetable growing - industry - innovations - improvement - costs
Henk Hak opent als voorzitter van het Vigef Platform de Landelijke Industriegroentendag op 24 augustus 2007 in Vredepeel. Hak ziet een zonnige toekomst voor industriegroenten in Nederland, mits de sector blijft innoveren
Verhalen over falen. Probleemdefinities van leerlingen van particuliere scholen
Weenink, D. ; Regt, A. de - \ 2006
In: Waarneming, analyse en reflectie. Kwalitatief onderzoek: de praktijk / Hak, T., Wester, F., - p. 45 - 59.
Neutrophil superoxide-anion generating capacity in chronic smoking: effect of long-term alpha-tocopherol therapy
Tits, L. van; Waart, F. de; Hak-Lemmers, H.L.M. ; Graaf, J. de; Demacker, P.N. ; Stalenhoef, A.F. - \ 2003
Journal of Biosciences 28 (2003)1. - ISSN 0250-5991 - p. 23 - 27.
low-density-lipoprotein - kinase-c activity - vitamin-e - invitro oxidation - supplementation - activation
We investigated whether long-term alpha-tocopherol therapy in chronic smoking affects superoxide generating capacity of neutrophils ex vivo. To this purpose, we randomly assigned 128 male chronic smokers (37 21 pack years of smoking) to treatment with placebo (n = 64) or alpha-tocopherol (400 IU dL-alpha-tocopherol daily, n = 64). After two years of therapy, we measured phorbol 12-myristate 13 -acetate- induced superoxide production of isolated neutrophils and of diluted whole blood by monitoring reduction of ferricytochrome c and luminol-enhanced peroxidase-catalyzed chemiluminescence. Plasma lipids and lipoproteins were not different between the two treatment groups. As expected, concentrations of alpha-tocopherol in plasma and in low-density lipoproteins were markedly elevated in the supplemented group compared to the placebo group (+ 120%, P <0.0001 and + 83%, P <0.0001, respectively). Consequently, resistance to in vitro oxidation of low-density lipoproteins (reflected by lag time of conjugated diene formation) was higher in the supplemented group than in the placebo group (+ 22%, P <0.0001). Superoxide generating capacity of neutrophils and superoxide production in diluted whole blood did not differ between α-tocopherol and placebo group. It is concluded that in chronic smoking long-term supranormal α-tocopherol intake does not reduce neutrophil superoxide-anion generating capacity, despite large increases in the concentrations of α-tocopherol in plasma and in low-density lipoproteins.
Effects of alpha-tocopherol on superoxide production and plasma intercellular adhesion molecule-1 and antibodies to oxidized LDL in chronic smokers
Tits, L.J. van; Waart, F. de; Hak-Lemmers, H.L.M. ; Heijst, P. ; Graaf, J. de; Demacker, P.N. ; Stalenhoef, A.F. - \ 2001
Free Radical Biology and Medicine 30 (2001)10. - ISSN 0891-5849 - p. 1122 - 1129.
low-density-lipoprotein - coronary-artery disease - human endothelial-cells - apparently healthy-men - protein-kinase-c - cigarette-smoking - vitamin-e - carotid atherosclerosis - lipid-peroxidation - heart-disease
Antioxidants have been postulated to exert beneficial effects in atherosclerosis. Atherosclerosis is associated with raised plasma levels of soluble intercellular adhesion molecule-1 (sICAM-1) and autoantibodies against oxidized low-density lipoprotein (oxLDL). It is not known whether antioxidants affect these plasma factors in chronic smokers. In a randomized double-blind placebo-controlled study involving 128 male normolipidemic chronic smokers the effect of a 2-year a-tocopherol treatment (400 IU dL-a-tocopherol daily) on plasma levels of sICAM-1 and autoantibodies against oxLDL was evaluated. In addition, we monitored production of superoxide by leukocytes ex vivo. It was found that compared to nonsmokers (n = 33) plasma levels of IgG but not IgM autoantibodies against oxLDL and concentrations of sICAM-1 in smokers were significantly elevated (30 and 42%, respectively). After supplementation with a-tocopherol concentration of TBARS in plasma and in vitro oxidizability of LDL had decreased, but autoantibodies and sICAM-1 had not changed. Production of superoxide was not different between a-tocopherol- and placebo-treated smokers. It is concluded that in chronic smokers, long-term treatment with a-tocopherol does not normalize the raised levels of sICAM-1 and autoantibodies against oxLDL, both risk factors for initiation or progression of cardiovascular disease, despite a decrease in in vitro oxidizability of LDL.
Alpha-tocopherol does not suppress elevated plasma levels of soluble intercellular adhesion molecule-1 and IgG autoantibodies against oxidized LDL in male smokers
Tits, L.J.H. van; Waart, F.G. de; Hak-Lemmers, H.L. ; Heijst, P. - \ 2000
In: Abstracts XIIth International Symposium on Atherosclerosis,June 25-29,2000,Stockholm,Sweden Elsevier - p. 188 - 189.
Wees alert op spruitremming van uw aardappelen
Hak, P. - \ 2000
Aardappelwereld 54 (2000)1. - ISSN 0169-653X - p. 23 - 25.
aardappelen - solanum tuberosum - kiemremmers - kiemremming - opslag - behoud - bestraling - kiemrust - groeivertraging - vegetatieve organen van de plant - potatoes - germination inhibitors - sprout inhibition - storage - preservation - irradiation - seed dormancy - growth retardation - plant vegetative organs
Het voorkomen van kieming bij bewaaraardappelen. Denk daarbij vooral aan: kiembeheersing bij consumptieaardappelen; kiemrust; beheersing van de kiemrust tijdens de bewaring; chemisch remmen van de kieming; natuurlijke kiemremmers
Lange bewaring van fritesaardappelen : afgerijpt produkt biedt goede perspectieven
Hak, P. ; Hoof, M. van - \ 2000
Aardappelwereld 54 (2000)4. - ISSN 0169-653X - p. 13 - 15.
aardappelen - solanum tuberosum - opslag - koelen - houdbaarheid (kwaliteit) - opslagkwaliteit - rijpheid - rijp worden - aardappelproducten - temperatuur - chemische analyse - chemische samenstelling - monosacchariden - potatoes - storage - cooling - keeping quality - storage quality - maturity - ripening - potato products - temperature - chemical analysis - chemical composition - monosaccharides
Rubrieken binnen dit artikel: invloed op bewaarresultaat; het ras; fysiologisch stadium; zorgvuldige handling; drogen en wondhelen; afkoelen; beheersing CO2 concentratie; beheersing spruiting; temperatuurbeleid tijdens bewaring
Toepassing van Diabolo op met spuitremmingsmiddelen behandelde consumptie-aardappelen : resultaten van een bewaarexperiment, uitgevoerd op ATO-DLO proefboerderij "De Eest" (NOP), in bewaarseizoen 1998/1999
Hak, P.S. ; Sinke, J. ; Bunk, G. ; Groenewoud, K. ; Sewtahal, H. ; Kleef, W. van - \ 1999
Wageningen : ATO-DLO (ATO-DLO rapport B403) - 12
Control of storage diseases with plant production products : results of a storage experiment performed by ATO-DLO research institute, Wageningen (Holland) in the 1998/1999 storage season
Hak, P.S. ; Kleef, W. van; Sewtahal, H. ; Sinke, J. ; Groenewoud, K. ; Bunk, G. - \ 1999
Wageningen : ATO-DLO (ATO-DLO report B402) - 12
Overwegingen bij het inschuren van aardappelen
Hak, P.S. ; Hoof, M. van - \ 1999
Aardappelwereld 53 (1999)10. - ISSN 0169-653X - p. 25 - 27.
aardappelen - opslag - gasbewaring - behoud - kwaliteit - potatoes - storage - controlled atmosphere storage - preservation - quality
Een aantal aspecten omtrent het inschuren op een rij
Pootgoed kan goed worden bewaard met buitenluchtkoeling
Hak, P.S. ; Hartmans, K.J. - \ 1999
Aardappelwereld 53 (1999)8. - ISSN 0169-653X - p. 31 - 33.
pootaardappelen - opslag - gasbewaring - koelen - koelsystemen - kiemrust - seed potatoes - storage - controlled atmosphere storage - cooling - cooling systems - seed dormancy
Uit onderzoek kan worden afgeleid dat de invloed van de hoogte van de bewaarpemperatuur tot medio eind november minder groot is op het kiemgedrag dan mogelijk werd aangenomen
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