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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Hot topic: Automated assessment of reticulo-ruminal motility in dairy cows using 3-dimensional vision
Song, X. ; Tol, P.P.J. van der; Groot Koerkamp, P.W.G. ; Bokkers, E.A.M. - \ 2019
Journal of Dairy Science 102 (2019)10. - ISSN 0022-0302 - p. 9076 - 9081.
3-dimensional camera - automatic - dairy cattle - ruminal motility

Reticulo-ruminal motility is a well-established indicator of gastrointestinal health in dairy cows. The currently available methods for assessing motility are labor-intensive, costly, and impractical to use regularly for all cows on a farm. We hypothesized that the reticulo-ruminal motility of dairy cows could be assessed automatically and remotely using a low-cost 3-dimensional (3D) camera. In this study, a 3D vision system was constructed and mounted on the frame of an automatic milking robot to capture the left paralumbar fossa of 20 primiparous cows. For each cow, the system recorded 3D images at 30 frames per second during milking. Each image was automatically processed to locate the left paralumbar fossa region and quantify its average concavity. Then, the average concavity values from all images of 1 cow during 1 milking process were chronologically assembled to form an undulation signal. By applying fast Fourier transformation to the signal, we identified cyclic oscillations that occurred in the same frequency range as reticulo-ruminal contractions. To validate the oscillation identification, 2 trained assessors visually identified reticulo-ruminal contractions from the same 3D image recordings on screen. The matching sensitivity between the automatically identified oscillations and the manually identified reticulo-ruminal contractions was 0.97. This 3D vision system can automate the assessment of reticulo-ruminal motility in dairy cows. It is noninvasive and can be implemented on farms without distressing the cows. It is a promising tool for farmers, giving them regular information about the gastrointestinal health of individual cows and helping them in daily farm management.

In de ban van het licht: Rob van Tol maakt slimme vallen met led
Tol, Rob van - \ 2019
Impact of land use and land cover transitions and climate on evapotranspiration in the Lake Naivasha Basin, Kenya
Odongo, Vincent Omondi ; Oel, Pieter Richard van; Tol, Christiaan van der; Su, Zhongbo - \ 2019
Science of the Total Environment 682 (2019). - ISSN 0048-9697 - p. 19 - 30.
Agricultural abandonment - LUCC - Reanalysis - Remote sensing - SEBS

The Lake Naivasha Basin in Kenya has experienced significant land use cover changes (LUCC) that has been hypothesized to have altered the hydrological regime in recent decades. While it is generally recognized that LUCC will impact evapotranspiration (ET), the precise nature of such impact is not very well understood. This paper describes how land use conversions among grassland and croplands have influenced ET in the Lake Naivasha Basin for the period 2003 to 2012. MODIS data products were used in combination with the European Centre for Medium-Range Weather Forecasts (ECMWF) data sets to model ET using the Surface Energy Balance System (SEBS). The results indicate that conversions from grassland to cropland accounted for increases in ET of up to 12% while conversion from cropland back to grasslands (abandonment) reduced ET by ~4%. This suggests that recently cultivated agricultural lands could increase local water demands, while abandonment of the farms could decrease the water loss and eventually increase the water availability. Also, recovery of ET following re-conversion from cropland to grassland might be impeded due to delayed recovery of soil properties since parts of the catchment are continuously being transformed with no ample time given for soil recovery. The annual ET over the 10 years shows an estimated decline from 724 mm to 650 mm (~10%). This decline is largely explained by a reduction in net radiation, an increase in actual vapour pressure whose net effect also led to decrease in the surface-air temperature difference. These findings suggest that in order to better understand LUCC effects on water resources of Lake Naivasha, it is important to take into account the effect of LUCC and climate because large scale changes of vegetation type from grassland to cropland substantially will increase evapotranspiration with implications on the water balance.

Human Milk Short-Chain Fatty Acid Composition is Associated with Adiposity Outcomes in Infants
Prentice, Philippa M. ; Schoemaker, Marieke H. ; Vervoort, Jacques ; Hettinga, Kasper ; Lambers, Tim T. ; Tol, Eric A.F. van; Acerini, Carlo L. ; Olga, Laurentya ; Petry, Clive J. ; Hughes, Ieuan A. ; Koulman, Albert ; Ong, Ken K. ; Dunger, David B. - \ 2019
The Journal of Nutrition 149 (2019)5. - ISSN 0022-3166 - p. 716 - 722.
breast milk - growth - lipids - nutrition - short chain fatty acids - weight

BACKGROUND: Presumed benefits of human milk (HM) in avoiding rapid infancy weight gain and later obesity could relate to its nutrient composition. However, data on breast milk composition and its relation with growth are sparse. OBJECTIVE: We investigated whether short-chain fatty acids (SCFAs), known to be present in HM and linked to energy metabolism, are associated with infancy anthropometrics. METHODS: In a prospective birth cohort, HM hindmilk samples were collected from 619 lactating mothers at 4-8 wk postnatally [median (IQR) age: 33.9 (31.3-36.5) y, body mass index (BMI) (kg/m2): 22.8 (20.9-25.2)]. Their offspring, born at 40.1 (39.1-41.0) wk gestation with weight 3.56 (3.22-3.87) kg and 51% male, were assessed with measurement of weight, length, and skinfold thickness at ages 3, 12, and 24 mo, and transformed to age- and sex-adjusted z scores. HM SCFAs were measured by 1H-nuclear magnetic resonance spectroscopy (NMR) and GC-MS. Multivariable linear regression models were conducted to analyze the relations between NMR HM SCFAs and infancy growth parameters with adjustment for potential confounders. RESULTS: NMR peaks for HM butyrate, acetate, and formic acid, but not propionate, were detected. Butyrate peaks were 17.8% higher in HM from exclusively breastfeeding mothers than mixed-feeding mothers (P = 0.003). HM butyrate peak values were negatively associated with changes in infant weight (standardized B = -0.10, P = 0.019) and BMI (B = -0.10, P = 0.018) between 3 and 12 mo, and negatively associated with BMI (B = -0.10, P = 0.018) and mean skinfold thickness (B = -0.10, P = 0.049) at age 12 mo. HM formic acid peak values showed a consistent negative association with infant BMI at all time points (B < = -0.10, P < = 0.014), whereas HM acetate was negatively associated with skinfold thickness at 3 mo (B = -0.10, P = 0.028) and 24 mo (B = -0.10, P = 0.036). CONCLUSIONS: These results suggest that HM SCFAs play a beneficial role in weight gain and adiposity during infancy. Further knowledge of HM SCFA function may inform future strategies to support healthy growth.

Automated body condition scoring of dairy cows using 3-dimensional feature extraction from multiple body regions
Song, X. ; Bokkers, E.A.M. ; Mourik, S. van; Groot Koerkamp, P.W.G. ; Tol, P.P.J. van der - \ 2019
Journal of Dairy Science 102 (2019)5. - ISSN 0022-0302 - p. 4294 - 4308.
3-dimensioanl camera - automatic - body condition score - dairy cattle

Machine vision technology has been used in automated body condition score (BCS) classification of dairy cows. The current vision-based classifications use information acquired from a limited number of body regions of the cow. Our study aimed to improve automated BCS classification by including multiple body condition–related features extracted from 3 viewpoints in 8 body regions. The data set of this study included 44 lactating cows with their BCS evenly distributed over the scale of BCS from 1.5 to 4.5 units. The body images of these cows were recorded over 2 consecutive days using 3-dimensional cameras positioned to view the cow from the top, right side, and rear. Each image was automatically processed to identify anatomical landmarks on the body surface. Around these anatomical landmarks, the bony prominences and body surface depressions were quantified to describe 8 body condition–related features. A manual BCS of each cow was independently assigned by 2 trained assessors using the same predefined protocol. With the extracted features as inputs and manual BCS as the reference, we built a nearest-neighbor classification model to classify BCS and obtained an overall classification sensitivity of 0.72 using a 10-fold cross-validation. We conclude that the sensitivity of automated BCS classification has been improved by expanding the selection of body condition–related features extracted from multiple body regions.

Quantitative proteomics reveals the crucial role of YbgC for Salmonella enterica serovar Enteritidis survival in egg white
Qin, Xiaojie ; He, Shoukui ; Zhou, Xiujuan ; Cheng, Xu ; Huang, Xiaozhen ; Wang, Yanyan ; Wang, Siyun ; Cui, Yan ; Shi, Chunlei ; Shi, Xianming - \ 2019
International Journal of Food Microbiology 289 (2019). - ISSN 0168-1605 - p. 115 - 126.
Chicken egg white - iTRAQ - Salmonella - Survival mechanisms - YbgC

Salmonella enterica serovar Enteritidis (S. Enteritidis) is a food-borne bacterial pathogen that can cause human salmonellosis predominately by contamination of eggs and egg products. However, its survival mechanisms in egg white are not fully understood, especially from a proteomic point of view. In this study, the proteomic profiles of S. Enteritidis in Luria-Bertani (LB) broth containing 50% and 80% egg white, and in whole egg white were compared with the profile in LB broth using iTRAQ technology to identify key proteins that were involved in S. Enteritidis survival in egg white. It was found that there were 303, 284 and 273 differentially expressed proteins in S. Enteritidis after 6 h exposure to whole, 80% and 50% egg white, respectively. Most of up-regulated proteins were primarily associated with iron acquisition, cofactor and amino acid biosynthesis, transporter, regulation and stress responses, whereas down-regulated proteins were mainly involved in energy metabolism, virulence as well as motility and chemotaxis. Three stress response-related proteins (YbgC, TolQ, TolA) of the tol-pal system responsible for maintaining cell membrane stability of Gram-negative bacteria were up-regulated in S. Enteritidis in response to whole egg white. Interestingly, deletion of ybgC resulted in a decreased resistance of S. Enteritidis to egg white. Compared with the wild type and complementary strains, a 3-log population reduction was observed in △ybgC mutant strain after incubation in whole egg white for 24 h. Cellular morphology of △ybgC mutant strain was altered from rods to spheres along with cell lysis in whole egg white. Furthermore, deletion of ybgC decreased the expression of tol-pal system-related genes (tolR, tolA). Collectively, these proteomic and mutagenic analysis reveal that YbgC is essential for S. Enteritidis survival in egg white.

Visual scores or subcutaneous fat thickness measurements, which is better for designing a 3D vision-technology body condition assessment method
Bokkers, Eddie ; Leijdekkers, Elles ; Song, X. ; Tol, J.J.P. van der - \ 2018
In: AgEng Conference 2018: New engineering concepts for a valued agriculture. - - p. 62 - 62.
Assessing body condition (BC) of dairy cows is a way to collect information about their fat reserves, which is essential for effective feeding management. 3D vision-technology might offer the opportunity to automatically and frequently assess BC. Daily monitoring provides a short feedback-loop of changes in fat reserves. Hence, feedings strategies can be optimized which is beneficial from an economic (lower costs), environmental (lower emissions) and animal welfare (lower disease incidences) perspective. This study aimed to determine whether visual scores or subcutaneous fat thickness measurement is better to design
a system using 3D vision-technology to predict BC scores. Cows (n=46) ranging in BC score on a 5-point-scale from 1 (lean) to 5 (fat) were preselected on four farms. For eight body parts,
BC scores (1-5) given by two observers independently via visual observation and subcutaneous fat thicknesses (mm) measured by ultrasound were related with corresponding 3D variables. The three methodologies were conducted twice on two consecutive days. Only two body parts, i.e. sacral ligament and line between spinous process and tips of short ribs could be assessed by all three
methodologies (ultrasound was limiting). The inter- and intra-observer agreement (kappa) for visual observation ranged from 0.52 to 0.71 and 0.50 to 0.69 for the two body parts respectively. Correlation coefficients between days for the two body parts were 0.72 and 0.88 for subcutaneous fat thickness and 0.91 and 0.96 for 3D vision variables. Furthermore, 3D vision variables
of the two body parts correlated better with visual observations (range 0.79-0.88) than with subcutaneous fat thickness (range 0.55-0.69). Despite the high precision of the ultrasound device, this method appeared labour intensive and only delivered useful information for two body parts. Instead visual observations were made on all eight body parts and showed better potential for predictive BC models using 3D vision variables.
Automatic body condition scoring in dairy cow using multiple 3D cameras
Song, X. ; Bokkers, Eddie ; Mourik, S. van; Tol, P.P.J. van der; Groot Koerkamp, P.W.G. - \ 2018
Automated identification of dairy cow hook and pin bones in three-dimensional vision
Song, X. ; Bokkers, Eddie ; Tol, P.P.J. van der; Groot Koerkamp, P.W.G. - \ 2018
Collectief onderzoek brengt nuttige informatie boven tafel
Tol, Rob van - \ 2018

Met een nieuw contract getekend waarin de private en publieke middelen voor kennis en innovatie voor 2018 en 2019 zijn vastgelegd, leek het de Topsector T&U zinvol de oogst over 2017 te delen via een publicatie. Drie onderzoeken nader belicht. Voorbeelden die nodig zijn om aan de toekomsteisen te voldoen en de sector vitaal te houden.

The development of attractants for monitoring and tools for biocontrol of the red rust thrips (C. signipennis)
Tol, R.W.H.M. van; Dooremalen, J.A. van; Tom, Jolanda - \ 2018
Report of FONTAGRO project “Strengthening small producers of organic bananas: integration of actors, sustainable pest management and strategies of health of soils”.
Aanpak taxuskever
Tol, R.W.H.M. van - \ 2018
Tuin en Landschap (2018). - ISSN 0165-3350
(n.a.v. KNPV dag)
Verkenning toekomst gewasbescherming Beschermde Appelteelt
Maas, M.P. van der; Helsen, H.H.M. ; Wenneker, M. ; Winkler, K. ; Jong, P.F. de; Tol, R.W.H.M. van; Groot, G.A. de; Lotz, L.A.P. ; Balkhoven, H. - \ 2018
Beschermde appelteelt; Bestrijding van appelzaagwesp door wegvangen
Helsen, H.H.M. ; Sluis, B.J. van der; Tol, R.W.H.M. van; Groot, G.A. de; Kats, R.J.M. van; Maas, M.P. van der - \ 2018
- 2 p.
Voor de bestrijding van appelzaagwesp (Hoplocampatestudinea) zijn fruittelers afhankelijk van chemische middelen. Verschillende van deze middelen staan op de EU lijst “Candidates forsubstitution” en zullen op termijn mogelijk verdwijnen. Voor de biologische teelt zijn in Nederland geen middelen voor de bestrijding van appelzaagwesp toegelaten. In het project Beschermde Teelt zoeken we daarom naar alternatieve, niet-chemische bestrijdingsmethoden.
Looking through the eyes of thrips
Tol, Rob van - \ 2018
Catalyst workshop on vision of thrips
Tol, Rob van - \ 2018
Insecten in de tuin.
Tol, Rob van - \ 2018
Hoe ziet trips zijn omgeving?
Tol, Rob van - \ 2018
Kleuren, geuren en andere factoren die gedrag beïnvloeden. Titel: Kruip in de huid van trips De glastuinbouwsector worstelt al jaren met de bestrijding van trips. De laatste jaren zijn mooie resultaten behaald met biologische bestrijding, maar in diverse teelten zorgt trips nog voor grote problemen. In deze workshop willen we terug naar de basis en in de huid van trips kruipen. Hoe en wanneer vliegt trips? Hoe kijkt een trips? Welke geuren vinden ze lekker en welke niet? Hoe planten ze zich voort? Hoe gedraagt een trips zich op de plant? Onderzoekers Rob van Tol en Gerben Messelink van Wageningen University & Research nemen je mee in de wereld van trips en presenteren de meest recente kennis over het gedrag van trips. Meer basiskennis helpt om deze plaag gerichter en effectiever te bestrijden. De workshop zal starten met een interactieve tripsquiz om uw kennis over deze belangrijke plaag te testen. Deelnemers aan deze workshop worden aangeraden de app kahoot alvast te downloaden op mobiel of tablet.
Resultaten 2017 tot januari 2018
Tol, R.W.H.M. van - \ 2018
Resultaten tot juni 2018
Tol, R.W.H.M. van - \ 2018
labproeven (trips/wantsen) en praktijkproeven 2018 (trips)
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