Onderzoek naar een kennisbasis voor natuurgedreven landbouw
Dijk, J. van; Veer, G. van der; Woestenburg, M. ; Stoop, J. ; Wijdeven, M. ; Veluw, K. van; Schrijver, R. ; Akker, J. van den; Woudenberg, E. van; Kerkhoven, D. ; Slot, M. - \ 2020
WINK - 52
In utero behavioral imprinting to predation risk in pups of the bank vole
Sievert, Thorbjörn ; Kerkhoven, Arjane ; Haapakoski, Marko ; Matson, Kevin D. ; Ylönen, Olga ; Ylönen, Hannu - \ 2020
Behavioral Ecology and Sociobiology 74 (2020)2. - ISSN 0340-5443
Alarm pheromone - Cross-generational effects - Odor - Olfaction - Predation risk
Abstract: In the predator–prey arms race, survival-enhancing adaptive behaviors are essential. Prey can perceive predator presence directly from visual, auditory, or chemical cues. Non-lethal encounters with a predator may trigger prey to produce special body odors, alarm pheromones, informing conspecifics about predation risks. Recent studies suggest that parental exposure to predation risk during reproduction affects offspring behavior cross-generationally. We compared behaviors of bank vole (Myodes glareolus) pups produced by parents exposed to one of three treatments: predator scent from the least weasel (Mustela nivalis nivalis); scent from weasel-exposed voles, i.e., alarm pheromones; or a control treatment without added scents. Parents were treated in semi-natural field enclosures, but pups were born in the lab and assayed in an open-field arena. Before each behavioral test, one of the three scent treatments was spread throughout the test arena. The tests followed a full factorial design (3 parental treatments × 3 area treatments). Regardless of the parents’ treatment, pups exposed to predator odor in the arena moved more. Additionally, pups spend more time in the center of the arena when presented with predator odor or alarm pheromone compared with the control. Pups from predator odor–exposed parents avoided the center of the arena under control conditions, but they spent more time in the center when either predator odor or alarm pheromone was present. Our experiment shows that cross-generational effects are context-sensitive, depending on the perceived risk. Future studies should examine cross-generational behavioral effects in ecologically meaningful environments instead of only neutral ones. Significance statement: We exposed bank voles to odors signaling predation risk to assess the effects parental predation exposure on the behavior of their offspring. Besides predator odor, we also assessed the role of a conspecific alarm cue as a novel way of spreading the predation risk information. Pup behaviors were assessed in the open-field arena, a standard way of assessing animal behavior in a wide range of contexts. We found that also alarm pheromone increased the time pups spend in the center of the arena similarly to predator odor. While previous studies suggested that offspring would be more fearful, our results indicate that the cross-generational effects are very context-dependent; i.e., they differ significantly depending on which scent cue is presented in the open-field arena. This shows the need for better tools or measurements to translate laboratory results into ecologically meaningful frameworks.
MAGIC: Biobased alternative for sound- and vibration-reducing materials in railway fastening systems
Blaauw, R. ; Vogelzang, W. ; Knoop, J.R.I. ; Thiyagarajan, S. ; Es, D.S. van; Ridderikhoff, Hans ; Smits, Angela ; Honcoop, Erwin ; Houwen, Gerrien van der; Kerkhoven, Joost ; Koteris, Stefan - \ 2016
Wageningen UR Food & Biobased Research is working on the development of environmentally-friendly resins for elastic rail fastening systems for railway track. Currently the resins for these systems are petroleum-based polyurethanes. In the MAGIC project, Wageningen UR is working with Dutch companies edilon)(sedra and Croda.
Floriculture for the Republic of Rwanda : Review Study Requested by the Government of Rwanda
Kerkhoven, P.M. ; Hagman, H. ; Baarveld, H.R. ; Elings, A. ; Hamel, E. - \ 2014
Kigali, Rwanda : Embassy of the Kingdom of the Netherlands - 107
Kerkhoven schuilplaats voor zeldzame zwammen
Boomsluiter, M. - \ 2011
Wageningen : Nature Today
|Assessment of wind erosion risk in Flanders, Belgium
Cornelis, W. ; Kerkhoven, S. Van; Riksen, M.J.P.M. ; Gabriels, D. - \ 2011
In: Land degradation processes and assessment : wind erosion, interrill erosion, gully erosion, land cover features / Vermang, J., Gabriels, D., de Boever, M., Cornelis, W., Ghent, Belgium : UNESCO chair of Eremology - ISBN 9789059894396 - p. 53 - 62.
|Her gebruik van GPS in de landbouw
Goense, Daan - \ 2005
Complete genome sequence of Lactobacillus plantarum WCFS1
Kleerebezem, M. ; Boekhorst, J. te; Kranenburg, R. van; Molenaar, D. ; Kuipers, O.P. ; Leer, R. ; Tarchini, R. ; Peters, S.A. ; Sandbrink, H.M. ; Fiers, M.W.E.J. ; Stiekema, W.J. ; Klein Lankhorst, R.M. ; Bron, P.A. ; Hoffer, S.M. ; Nierop Groot, M.N. ; Kerkhoven, R. ; Vries, M.C. de; Ursing, B. ; Vos, W.M. de; Siezen, R.J. - \ 2003
Proceedings of the National Academy of Sciences of the United States of America 100 (2003)4. - ISSN 0027-8424 - p. 1990 - 1995.
lactic-acid bacteria - resistant staphylococcus-aureus - bacillus-subtilis - genes - cloning - chromosome - expression - metabolism - manganese - knockout
The 3,308,274-bp sequence of the chromosome of Lactobacillus plantarum strain WCFS1, a single colony isolate of strain NCIMB8826 that was originally isolated from human saliva, has been determined, and contains 3,052 predicted protein-encoding genes. Putative biological functions could be assigned to 2,120 (70%) of the predicted proteins. Consistent with the classification of L. plantarum as a facultative heterofermentative lactic acid bacterium, the genome encodes all enzymes required for the glycolysis and phosphoketolase pathways, all of which appear to belong to the class of potentially highly expressed genes in this organism, as was evident from the codon-adaptation index of individual genes. Moreover, L. plantarum encodes a large pyruvate-dissipating potential, leading to various end-products of fermentation. L. plantarum is a species that is encountered in many different environmental niches, and this flexible and adaptive behavior is reflected by the relatively large number of regulatory and transport functions, including 25 complete PTS sugar transport systems. Moreover, the chromosome encodes >200 extracellular proteins, many of which are predicted to be bound to the cell envelope. A large proportion of the genes encoding sugar transport and utilization, as well as genes encoding extracellular functions, appear to be clustered in a 600-kb region near the origin of replication. Many of these genes display deviation of nucleotide composition, consistent with a foreign origin. These findings suggest that these genes, which provide an important part of the interaction of L. plantarum with its environment, form a lifestyle adaptation region in the chromosome.
|Zuid-Afrika en Nederland: Over aardappelteelt en oude en nieuwe verbindingen
Haverkort, A.J. ; Kerkhoven, P.M. ; Coumou, D. - \ 1996
Aardappelwereld 50 (1996)1. - ISSN 0169-653X - p. 31 - 36.
nederland - aardappelen - solanum tuberosum - zuid-afrika - netherlands - potatoes - solanum tuberosum - south africa
Het Nivaa en het Nederlandse Ministerie van Landbouw en de Zuid-Afrikaanse organisatie van Aardappeltelers hebben gedurende de eerste helft van december 1995 een serie lezingen georganiseerd in de voornaamste aardappelteeltgebieden in Zuid Afrika. In dit artikele wordt verslag gedaan van de aardappelteelt in Zuid Afrika, Zuid Afrika als land en de vooruitzichten
Computersystemen ter ondersteuning en vervanging van industriele persoonlijke verkoop : een studie vanuit de marktkunde, informatica en operationele research
Kerkhoven, J. - \ 1991
Agricultural University. Promotor(en): M.T.G. Meulenberg; M.S. Elzas; P. van Beek. - S.l. : Kerkhoven - 376
analyse van besluiten - computeranalyse - verkoopbevordering - adverteren - ontwerp - systemen - computers - operationeel onderzoek - marketing - bedrijfsvoering - internet - software-ontwikkeling - computernetwerken - lokale netwerken - decision analysis - computer analysis - sales promotion - advertising - design - systems - computers - operations research - marketing - management - internet - software engineering - computer networks - local area networks
This thesis concerns computer systems which can either support or replace Industrial Personal Selling (IPS)
The objective of this study is to determine how IPS can be supported or replaced efficiently and effectively by computer systems. IPS is defined here as all activities aimed at face-to-face contact with the intention of realising a transaction. IPS-replacing systems are able to (partially) replace the face-to-face contact. IPS-supporting systems increase the efficiency and effectiveness of the IPS activities.
The parties involved in the face-to-face contact are the buying- and the selling-centre. Mostly, but not exclusively, sales representatives are involved in IPS from within the selling-centre. Members from technical departments are often involved from within the buying-centre, during the selection of products or materials. Members from purchasing departments are involved when suppliers have to be selected.
Five main activities can be distinguished when the operational activities of an industrial sales representative are studied (planning, preparation, conversation, reporting and follow-up). Each of these activities can be considered to a more or lesser extent, for support by means of computer systems.
Because more than one person within a buying-centre can be involved in face-to-face contact with a selling-centre, a classification of the activities of the buying process itself was chosen instead of a classification of the activities of the buyer. Seven phases are distinguished in the buying process (recognition of need, supplier search, definition of characteristics, evaluation of material, acquisition of offers, evaluation of offers and supplier selection).
The connection between the IPS-activities of the selling-centre with the buyingprocess of the buying-centre is made by means of the sales conversation. Six different types of conversation are distinguished (introduction, definition, control, commercial, repetition and fire-fighting). When a selling-centre has to deal with a new buying-centre, the following conversations will be held in order, before a transaction can be realised: introduction, definition, control and commercial conversation. IPS-replacing systems can be developed for each of these four types of sales conversation. The repetition and the fire-fighting conversation are not directly aimed at the realisation of a transaction.
The 4 types of sales conversation can be used as a connection between the 5 activities of the selling-proces and the 7 phases of the buying-process. This integrated interaction- model is used as a framework for the study.
Several Computer Science and Operations Research techniques and models have been used to work out the interaction model. Special attention is given to the mancomputer interface and the usability of Expert Systems and Hypertext Systems. Both types of systems prove to be partially useful for building IPS-replacing systems.
The Operations Research offers a number of tools 'models & algorithms) for developing decision-models for the different types of IPS-replacing systems. Two simple and two complex models have been worked out in detail. A complex lamination problem has been solved by means of a new Integer Linear Programming formulation. The sawing of plastic-sheets has been solved with the cutting-algorithm of Wang.
Several computer systems have been developed for the support or replacement of IPS. A Hypertext System has been built for the introduction conversation. A Decision Support System (EPOS Films) has been built for solving the lamination problem (special form of definition conversation) and a Decision Support System (EPOS Perspex) has been built to solve the sawing problem (special form of commercial conversation). These three systems have only been used as prototypes within the selling-centre. Ile Database Management System EPOS II (replacement definition conversation), the Expert Database System EPOS-F (replacement definition and control conversation) and the Database Management System HOLDAP 4.3 (IPS-support) have been used in practice by many sales representatives and customers. The successor of EPOS II (in 1990 version IV was launched) is being used by many thousands of buying-centres throughout the world. The concept of HOLDAP is being used by many hundreds of industrial sales representatives within the selling-organisation, that has been studied.
The research shows that EPOS II is used on average once every two weeks for 21 minutes by members of buying-centres. In the Netherlands in 1987 EPOS II was in use for approximately 8000 hours. The average industrial sales representative communicated in that year for approximately 120 hours on the same subjects.
EPOS II is being used by the sales representative as an IPS-supporting system. The system especially helps sales representatives with a commercial background who have to operate in a technically complex environment. As a result of the use of EPOS, new contacts with buying-centres have been established, extra requests for offers have been received and more turnover has been generated. The EPOS-concept has been adopted by (almost) all major chemical companies in the world.
The research on HOLDAP 4.3 shows that the amount of information in the buyingcentre increases significantly as a result of the use of HOLDAP. Based on these results an increase in effectiveness can be expected because of improved decision making. The efficiency of the sales representatives is not (yet) positively influenced by the use of HOLDAP and for some sales representatives their efficiency even decreases during the first months of use.
Important side-effects of HOLDAP are an improved and demonstrated willingness of sales representatives to work from home, less need for secretarial support and an increased job-satisfaction.
This study shows that Industrial Personal Selling can be supported or replaced efficiently and effectively in certain areas by computer systems. However there are areas where support or replacement is theoretically impossible, or practically undesirable. There is reason to believe that substantial theoretical and practical improvement in some areas of IPS can be expected in the coming years. Full replacement of IPS by computer systems and thereby the elimination of the need for IPS support , will still remain as fiction for many years to come.
|Een geheeltallig lineair programmeringsmodel t.b.v. het bepalen van de optimale samenstelling en volgorde van foliën in een laminaat.
Beek, P. van; Kerkhoven, C.J. ; Rooij, C.W.D.M. van - \ 1990
Kwantitatieve methoden : nieuwsbrief voor toegepaste statistiek en operationele research 35 (1990). - ISSN 1380-4162 - p. 5 - 20.
De voorbeelddorpen Kerkhoven en Rottevalle : een nieuwe methode van landbouwvoorlichting
Anonymous, - \ 1955
's-Gravenhage : L.E.I. (Rapport / Landbouw-Economisch Instituut no. 220) - 114
demonstratiebedrijven, landbouw - proefbedrijven - producten - informatie - landbouw - nederland - technische informatie - drenthe - noord-brabant - demonstration farms - pilot farms - products - information - agriculture - netherlands - technical information - drenthe - noord-brabant