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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Visualizing trypanosomes in a vertebrate host reveals novel swimming behaviours, adaptations and attachment mechanisms
Dóró, Éva ; Jacobs, Sem H. ; Hammond, Ffion R. ; Schipper, Henk ; Pieters, Remco P.M. ; Carrington, Mark ; Wiegertjes, Geert F. ; Forlenza, Maria - \ 2019
eLife 8 (2019). - ISSN 2050-084X
host-pathogen interaction - infectious disease - microbiology - swimming behavior - Trypanosoma carassii - zebrafish

Trypanosomes are important disease agents of humans, livestock and cold-blooded species, including fish. The cellular morphology of trypanosomes is central to their motility, adaptation to the host's environments and pathogenesis. However, visualizing the behaviour of trypanosomes resident in a live vertebrate host has remained unexplored. In this study, we describe an infection model of zebrafish (Danio rerio) with Trypanosoma carassii. By combining high spatio-temporal resolution microscopy with the transparency of live zebrafish, we describe in detail the swimming behaviour of trypanosomes in blood and tissues of a vertebrate host. Besides the conventional tumbling and directional swimming, T. carassii can change direction through a 'whip-like' motion or by swimming backward. Further, the posterior end can act as an anchoring site in vivo. To our knowledge, this is the first report of a vertebrate infection model that allows detailed imaging of trypanosome swimming behaviour in vivo in a natural host environment.

Exploring the functional role of the digital mucus glands and their secretions in tree frog attachment
Langowski, J.K.A. ; Singla, Saranshu ; Nyarko, Alex ; Schipper, H. ; Berg, Frank van den; Kaur, Sukhmanjot ; Astley, Henry C. ; Gussekloo, S.W.S. ; Dhinojwala, Ali ; Leeuwen, J.L. van - \ 2019
- 1 p.
Comparative and functional analysis of the digital mucus glands and secretions of tree frogs
Langowski, Julian K.A. ; Singla, Saranshu ; Nyarko, Alex ; Schipper, Henk ; Berg, Frank T. van den; Kaur, Sukhmanjot ; Astley, Henry C. ; Gussekloo, Sander W.S. ; Dhinojwala, Ali ; Leeuwen, Johan L. Van - \ 2019
Frontiers in Zoology 16 (2019). - ISSN 1742-9994
Cryo-histochemistry - Hyla cinerea - Infrared spectroscopy - Lubrication - Macrogland - Mucosubstance - Sum frequency generation spectroscopy - Synchrotron micro-computer-tomography - Wet adhesion

Background: Mucus and mucus glands are important features of the amphibian cutis. In tree frogs, the mucus glands and their secretions are crucial components of the adhesive digital pads of these animals. Despite a variety of hypothesised functions of these components in tree frog attachment, the functional morphology of the digital mucus glands and the chemistry of the digital mucus are barely known. Here, we use an interdisciplinary comparative approach to analyse these components, and discuss their roles in tree frog attachment.

Results: Using synchrotron micro-computer-tomography, we discovered in the arboreal frog Hyla cinerea that the ventral digital mucus glands differ in their morphology from regular anuran mucus glands and form a subdermal gland cluster. We show the presence of this gland cluster also in several other - not exclusively arboreal - anuran families. Using cryo-histochemistry as well as infrared and sum frequency generation spectroscopy on the mucus of two arboreal (H. cinerea and Osteopilus septentrionalis) and of two terrestrial, non-climbing frog species (Pyxicephalus adspersus and Ceratophrys cranwelli), we find neutral and acidic polysaccharides, and indications for proteinaceous and lipid-like mucus components. The mucus chemistry varies only little between dorsal and ventral digital mucus in H. cinerea, ventral digital and abdominal mucus in H. cinerea and O. septentrionalis, and between the ventral abdominal mucus of all four studied species.

Conclusions: The presence of a digital mucus gland cluster in various anuran families, as well as the absence of differences in the mucus chemistry between arboreal and non-arboreal frog species indicate an adaptation towards generic functional requirements as well as to attachment-related requirements. Overall, this study contributes to the understanding of the role of glands and their secretions in tree frog attachment and in bioadhesion in general, as well as the evolution of anurans.

ICON.NL: coastline observatory to examine coastal dynamics in response to natural forcing and human interventions
Aarninkhof, Stefan ; Schipper, Matthieu De; Luijendijk, Arjen ; Ruessink, Gerben ; Bierkens, Marc ; Wijnberg, Kathelijne ; Roelvink, Dano ; Limpens, J. ; Baptist, M.J. ; Riksen, Michel ; Bouma, Tjeerd ; Vries, Sierd de; Reniers, Ad ; Hulscher, Suzanne ; Wijdeveld, Arjan ; Dongeren, Ap van; Gelder-Maas, Carola van; Lodder, Quirijn ; Spek, Ad van der - \ 2019
- 8 p.
In the light of challenges raised by a changing climate and increasing population pressure in coastal regions, it has become clear that theoretical models and scattered experiments do not provide the data we urgently need to understand coastal conditions and processes. We propose a Dutch coastline observatory named ICON.NL, based at the Delfland Coast with core observations focused on the internationally well-known Sand Engine experiment, as part of an International Coastline Observatories Network (ICON). ICON.NL will cover the physics and ecology from deep water to the dunes. Data will be collected continuously by novel remote sensing and in-situ sensors, coupled to numerical models to yield unsurpassed long-term coastline measurements. The combination of the unique site and ambitious monitoring design enables new avenues in coastal science and a leap in interdisciplinary research.
Potential of novel desert microalgae and cyanobacteria for commercial applications and CO2 sequestration
Schipper, Kira ; Muraikhi, Mariam Al; Alghasal, Ghamza Saed H.S. ; Saadaoui, Imen ; Bounnit, Touria ; Rasheed, Rihab ; Dalgamouni, Tasneem ; Jabri, Hareb Mohammed S.J. Al; Wijffels, René H. ; Barbosa, Maria J. - \ 2019
Journal of Applied Phycology 31 (2019)4. - ISSN 0921-8971 - p. 2231 - 2243.
Carbon capture - CO - Cyanobacteria - Microalgae - Thermotolerance
CO2 fixation by phototrophic microalgae and cyanobacteria is seen as a possible global carbon emissions reducer; however, novel microalgae and cyanobacterial strains with tolerance to elevated temperatures and CO2 concentrations are essential for further development of algae-based carbon capture. Four novel strains isolated from the Arabian Gulf were investigated for their thermotolerance and CO2-tolerance, as well as their carbon capture capability. Two strains, Leptolyngbya sp. and Picochlorum sp., grew well at 40 °C, with productivities of 106.6 ± 10.0 and 87.5 ± 2.1 mg biomass L−1 d−1, respectively. Tetraselmis sp. isolate showed the highest biomass productivity and carbon capture rate of 157.7 ± 10.3 mg biomass L−1 d−1 and 270.8 ± 23.9 mg CO2 L−1 d−1, respectively, both at 30 °C. Under 20% CO2, the biomass productivity increased over 2-fold for both Tetraselmis and Picochlorum isolates, to 333.8 ± 41.1 and 244.7 ± 29.5 mg biomass L−1 d−1. These two isolates also presented significant amounts of lipids, up to 25.6 ± 0.9% and 28.0 ± 2.0% (w/w), as well as presence of EPA and DHA. Picochlorum sp. was found to have a suitable FAME profile for biodiesel production. Both Tetraselmis and Picochlorum isolates showed promising characteristics, making them valuable strains for further investigation towards commercial applications and CO2 capture.
Partial replacement of red and blue by green light increases biomass and yield in tomato
Kaiser, E. ; Weerheim, C. ; Schipper, R. ; Dieleman, J.A. - \ 2019
Scientia Horticulturae 249 (2019). - ISSN 0304-4238 - p. 271 - 279.
Light spectrum; Green light; Light use efficiency; Solanum lycopersicum
Effects of green light on plant growth are relatively understudied, and published results are contradictory. Although per unit leaf area, green light drives photosynthesis less efficiently than does red light, on a whole-plant level green light may increase growth due to changes in vertical light distribution, leaf light acclimation and canopy architecture. As most studies were conducted on small plants with compact stems, positive effects may have remained unnoticed. In a greenhouse experiment, a tomato (Solanum lycopersicum) crop was exposed to 7, 20 or 39% of green light in a background of narrow bandwidth red and blue light, as well as sunlight, for 76 days. The intensity supplied by lamps (171 μmol m−2 s−1) and the red:blue ratio were similar between treatments. Adding green light (+32%) to the spectrum significantly and linearly increased plant biomass and yield (+6.5%). With increasing green light percentage, there were tendencies for linear increases in leaf biomass (P = 0.06), specific leaf area (P = 0.09), stem biomass (P = 0.07), stem length (P = 0.05) and number of internodes (P = 0.05). In the top and middle leaf layers of the canopy, net photosynthesis rate, stomatal conductance and leaf thickness were unaffected by the treatment while in leaves in the middle leaf layer, chlorophyll a:b ratio and carotenoid concentrations increased with the percentage of green light. This study shows that partial replacement of red by green light increases growth of plants in dense canopies and suggests that the combined effects of a light spectrum on plant growth are more than the sum of wavelength effects on photosynthetic efficiency.
Adding Blue to Red Supplemental Light Increases Biomass and Yield of Greenhouse-Grown Tomatoes, but Only to an Optimum
Kaiser, M.E. ; Ouzounis, Theoharis ; Giday, Habtamu ; Schipper, R. ; Heuvelink, E. ; Marcelis, L.F.M. - \ 2019
Frontiers in Plant Science 9 (2019). - ISSN 1664-462X - 11 p.
LED, biomass, blue light, red light, photosynthesis, tomato, greenhouse, yield
Greenhouse crop production in northern countries often relies heavily on supplemental lighting for year-round yield and product quality. Among the different spectra used in supplemental lighting, red is often considered the most efficient, but plants do not develop normally when grown solely under monochromatic red light (“red light syndrome”). Addition of blue light has been shown to aid normal development, and typical lighting spectra in greenhouse production include a mixture of red and blue light. However, it is unclear whether sunlight, as part of the light available to plants in the greenhouse, may be sufficient as a source of blue light. In a greenhouse high-wire tomato (Solanum lycopersicum), we varied the percentage of blue supplemental light (in a red background) as 0, 6, 12, and 24%, while keeping total photosynthetically active radiation constant. Light was supplied as a mixture of overhead (99 μmol m-2 s-1) and intracanopy (48 μmol m-2 s-1) LEDs, together with sunlight. Averaged over the whole experiment (111 days), sunlight comprised 58% of total light incident onto the crop. Total biomass, yield and number of fruits increased with the addition of blue light to an optimum, suggesting that both low (0%) and high (24%) blue light intensities were suboptimal for growth. Stem and internode lengths, as well as leaf area, decreased with increases in blue light percentage. While photosynthetic capacity increased linearly with increases in blue light percentage, photosynthesis in the low blue light treatment (0%) was not low enough to suggest the occurrence of the red light syndrome. Decreased biomass at low (0%) blue light was likely caused by decreased photosynthetic light use efficiency. Conversely, decreased biomass at high (24%) blue light was likely caused by reductions in canopy light interception. We conclude that while it is not strictly necessary to add blue light to greenhouse supplemental red light to obtain a functional crop, adding some (6–12%) blue light is advantageous for growth and yield while adding 24% blue light is suboptimal for growth.
PCLake+ : A process-based ecological model to assess the trophic state of stratified and non-stratified freshwater lakes worldwide
Janssen, Annette B.G. ; Teurlincx, Sven ; Beusen, Arthur H.W. ; Huijbregts, Mark A.J. ; Rost, Jasmijn ; Schipper, Aafke M. ; Seelen, Laura M.S. ; Mooij, Wolf M. ; Janse, Jan H. - \ 2019
Ecological Modelling 396 (2019). - ISSN 0304-3800 - p. 23 - 32.
Deep lake - Food web model - Lake ecology - Limnology - Shallow lake - Thermal stratification

The lake ecosystem model PCLake is a process-based model that was developed to simulate water quality based on ecological interactions in shallow, non-stratifying lakes in the temperate climate zone. Here we present PCLake+, which extends the PCLake model to cover a wide range of freshwater lakes that differ in stratification regime and climate-related processes. To this end, the model was extended with a hypolimnion layer that can be invoked and configured by forcing functions or by simple built-in empirical relationships that impose stratification. Further adjustments to the original PCLake model have been made with respect to the calculation of 1) light irradiation in the water column, 2) evaporation processes and 3) phenology of macrophytes. The simulation output of PCLake+ for different types of lakes complies well with generally accepted limnological knowledge, thus holding promise for future contributions to ecological theory and application to lakes around the globe.

Bronnenanalyse nutriënten stroomgebied Maas
Schipper, Peter ; Renaud, Leo ; Boekel, Erwin van - \ 2019
Wageningen : Wageningen Environmental Research (Wageningen Environmental Research rapport 2931) - 81
De waterkwaliteit in Nederland – en ook in het Maasstroomgebied (Noord-Brabant en Limburg) – verbetert wel, maar dit gaat niet snel genoeg om de doelen die voor de Europese Kaderrichtlijn Water (KRW) zijn gesteld op tijd te halen. De stoffen stikstof en fosfor (nutriënten) zijn belangrijke factoren voor het bereiken van waterkwaliteitsdoelen. Om effectieve maatregelen te vinden, zijn gedegen gebiedsgerichte analyses nodig om bronnen van de belasting van het (grond)watermilieu door stoffen te kwantificeren. Deze analyses vormen de basis voor de maatregelen die in 2021 worden vastgesteld in de nationale stroomgebiedbeheerplannen (derde generatie SGBP’en) en regionale (water)plannen. De waterschappen en provincies in het Maasstroomgebied hebben behoefte aan een eenduidige analyse van de herkomst van de nutriënten in het oppervlaktewater. In opdracht van het Programmabureau KRW-DHZ Maasregio is onderzoek uitgevoerd naar de nutriëntenbelasting en de bronnen die deze belasting veroorzaken. Uit het onderzoek blijkt dat de totale nutriëntenbelasting van het oppervlaktewater in hoofdzaak worden bepaald door de diffuse uit- en afspoeling vanuit landbouwgronden, effluenten van rioolwaterzuiveringsinstallaties (RWZI’s), toestroming vanuit het buitenland en inlaat vanuit rijkswateren. Voor stikstof heeft actuele bemesting een groot aandeel (72%) in de uit- en afspoeling. Voor fosfor is dit aandeel kleiner (gemiddeld 33%). Binnen debeheersgebieden van de vier waterschappen zijn er per vanggebied grote verschillen tussen de belasting en herkomst. Enerzijds door de regionale verschillen tussen de af- en uitspoeling en het aandeel van de bemesting hierin, anderzijds door de lozingslocaties van RWZI’s, de toestroom vanuit het buitenland, inlaat vanuit rijkswater en de doorvoer van bovenstrooms gelegen waterlichamen, hetgeen sterk verschilt per gebied. Deze resultaten bieden de basis om scenario’s voor maatregelen op te stellen en effecten ervan op de waterkwaliteit te kwantificeren.
Light-dark rhythms during incubation of broiler chicken embryos and their effects on embryonic and post hatch leg bone development
Pol, C.W. van der; Roovert-Reijrink, Inge Van; Maatjens, C.M. ; Gussekloo, S.W.S. ; Kranenbarg, S. ; Wijnen, H.J. ; Pieters, R.P.M. ; Schipper, H. ; Kemp, B. ; Brand, H. van den - \ 2019
PLoS ONE (2019). - ISSN 1932-6203 - 17 p.
There are indications that lighting schedules applied during incubation can affect leg health at hatching and during rearing. The current experiment studied effects of lighting schedule: continuous light (24L), 12 hours of light, followed by 12 hours of darkness (12L:12D), or continuous darkness (24D) throughout incubation of broiler chicken eggs on the development and strength of leg bones, and the role of selected hormones in bone development. In the tibiatarsus and femur, growth and ossification during incubation and size and microstructure at day (D)0, D21, and D35 post hatching were measured. Plasma melatonin, growth hormone, and IGF-I were determined perinatally. Incidence of tibial dyschondroplasia, a leg pathology resulting from poor ossification at the bone’s epiphyseal plates, was determined at slaughter on D35. 24L resulted in lower embryonic ossification at embryonic day (E)13 and E14, and lower femur length, and lower tibiatarsus weight, length, cortical area, second moment of area around the minor axis, and mean cortical thickness at hatching on D0 compared to 12L:12D especially. Results were long term, with lower femur weight and tibiatarsus length, cortical and medullary area of the tibiatarsus, and second moment of area around the minor axis, and a higher incidence of tibial dyschondroplasia for 24L. Growth hormone at D0 was higher for 24D than for 12L:12D, with 24L intermediate, but plasma melatonin and IGF-I did not differ between treatments, and the role of plasma melatonin, IGF-I, and growth hormone in this process was therefore not clear. To conclude, in the current experiment, 24L during incubation of chicken eggs had a detrimental effect on embryonic leg bone development and later life leg bone strength compared to 24D and 12L:12D, while the light-dark rhythm of 12L:12D may have a stimulating effect on leg health.
Tissue specific expression and genomic organization of bitter sesquiterpene lactone biosynthesis in Cichorium intybus L. (Asteraceae)
Bogdanovic, Milica ; Cankar, K. ; Todorovic, Sladana ; Dragicevic, Milan ; Simonovic, Ana ; Houwelingen, A.M.M.L. van; Schijlen, E.G.W.M. ; Schipper, A. ; Gagneul, David ; Hendriks, Theo ; Quillet, Marie-Christine ; Bouwmeester, H.J. ; Bosch, H.J. ; Beekwilder, M.J. - \ 2019
Industrial Crops and Products 129 (2019). - ISSN 0926-6690 - p. 253 - 260.
Chicory (Cichorium intybus L.) produces bitter sesquiterpene lactones (STLs). Some enzymes in the biosynthetic pathway towards these compounds have been characterized. However, the genomic organization and tissue specificity of their biosynthesis is largely unknown. Concentrations of two sesquiterpene lactones and expression of genes involved in the first dedicated biosynthetic step were measured in different chicory tissues. BAC clones containing different genes encoding germacrene A synthase were sequenced, and revealed several tightly linked paralogs. Promoters of genes encoding two germacrene A synthases were fused to GFP and expressed in plants regenerated from transformed chicory hairy root cultures. Highest expression was observed in the epidermis of
leaves and external root tissue. This work opens the possibility to select for chicory germplasm diversified in STL content, and to study their role in chicory in defence and physiology.
Functional interpretation of the force-transmitting structures in a tree frog's toe pad
Langowski, J.K.A. ; Schipper, H. ; Berg, Frank van den; Blij, Anne ; Gussekloo, S.W.S. ; Leeuwen, J.L. van - \ 2018
In: SEB Florence 2018 abstract book 2: Animal biology abstracts. - - p. 152 - 152.
The morphology of tree frogs’ toe pads is adapted towards attachment, allowing these animals to move through their arboreal habitat. Whereas the superficial pad morphology has been studied extensively in previous research, little is known about the internal pad morphology and its functional relevance in attachment. We present the results of a 3-D characterisation and functional analysis of the internal toe pad morphology in the tree frog Hyla cinerea, combining histology, immunohistochemistry, synchrotron micro-computer-tomography, and finite element analysis. The morphology of force-transmitting pad structures, in particular of a collagen layer connecting the ventral epidermis with the medial phalanx, agrees in several aspects with the geometry of a pad model that is topologically optimised towards shear loading. This suggests that tree frogs’ toe pads are primarily adapted towards the transmission of shear loads, as experienced by the frogs while hanging on a vertical substrate. A collagenous septum running from the distal tip of the distal phalanx to the ventral cutis may play a role in peeling and detachment. Furthermore, we show that the adhesive toe pads of tree frogs contain smooth muscle fibre bundles with yet unknown functionality. Overall, our study contributes to the functional understanding of tree frog attachment, hence offering novel perspectives on the ecology, phylogeny, and evolution of anurans, as well as the design of tree-frog-inspired adhesives for technological applications.
Impacts of nitrogen addition on plant species richness and abundance : A global meta-analysis
Midolo, Gabriele ; Alkemade, Rob ; Schipper, Aafke M. ; Benítez-López, Ana ; Perring, Michael P. ; Vries, Wim de - \ 2018
Global Ecology and Biogeography (2018). - ISSN 1466-822X
anthropogenic impacts - biodiversity - eutrophication - global change - GLOBIO - soil acidification - vegetation

Aim: Experimental nitrogen (N) addition (fertilization) studies are commonly used to quantify the impacts of increased N inputs on plant biodiversity. However, given that plant community responses can vary considerably among individual studies, there is a clear need to synthesize and generalize findings with meta-analytical approaches. Our goal was to quantify changes in species richness and abundance in plant communities in response to N addition across different environmental contexts, while controlling for different experimental designs. Location: Global. Time period: Data range: 1985–2016; Publication years: 1990–2018. Major taxa studied: Plants. Methods: We performed a meta-analysis of 115 experiments reported in 85 studies assessing the effects of N addition on terrestrial natural and semi-natural plant communities. We quantified local-scale changes in plant biodiversity in relationship to N addition using four metrics: species richness (SR), individual species abundance (IA), mean species abundance (MSA) and geometric mean abundance (GMA). Results: For all metrics, greater amounts of annual N addition resulted in larger declines in plant diversity. Additionally, MSA decreased more steeply with N that was applied in reduced (NH4 +) rather than oxidized ((NO 3)) form. Loss of SR with increasing amounts of N was found to be larger in warmer sites. Furthermore, greater losses of SR were found in sites with longer experimental durations, smaller plot sizes and lower soil cation exchange capacity. Finally, reductions in the abundance of individual species were larger for N-sensitive plant life-form types (legumes and non-vascular plants). Main conclusions: N enrichment decreases both SR and abundance of plants in N-addition experiments, but the magnitude of the response differs among biodiversity metrics and with the environmental and experimental context. This underlines the importance of integrating multiple dimensions of biodiversity and relevant modifying factors into assessments of biodiversity responses to global environmental change.

A protocol for an intercomparison of biodiversity and ecosystem services models using harmonized land-use and climate scenarios
Kim, Hyejin ; Rosa, Isabel M.D. ; Alkemade, Rob ; Leadley, Paul ; Hurtt, George ; Popp, Alexander ; Vuuren, Detlef P. van; Anthoni, Peter ; Arneth, Almut ; Baisero, Daniele ; Caton, Emma ; Chaplin-Kramer, Rebecca ; Chini, Louise ; Palma, Adriana De; Fulvio, Fulvio Di; Marco, Moreno Di; Espinoza, Felipe ; Ferrier, Simon ; Fujimori, Shinichiro ; Gonzalez, Ricardo E. ; Gueguen, Maya ; Guerra, Carlos ; Harfoot, Mike ; Harwood, Thomas D. ; Hasegawa, Tomoko ; Haverd, Vanessa ; Havlík, Petr ; Hellweg, Stefanie ; Hill, Samantha L.L. ; Hirata, Akiko ; Hoskins, Andrew J. ; Janse, Jan H. ; Jetz, Walter ; Johnson, Justin A. ; Krause, Andreas ; Leclère, David ; Martins, Ines S. ; Matsui, Tetsuya ; Merow, Cory ; Obersteiner, Michael ; Ohashi, Haruka ; Poulter, Benjamin ; Purvis, Andy ; Quesada, Benjamin ; Rondinini, Carlo ; Schipper, Aafke M. ; Sharp, Richard ; Takahashi, Kiyoshi ; Thuiller, Wilfried ; Titeux, Nicolas - \ 2018
Geoscientific Model Development 11 (2018)11. - ISSN 1991-959X - p. 4537 - 4562.

To support the assessments of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), the IPBES Expert Group on Scenarios and Models is carrying out an intercomparison of biodiversity and ecosystem services models using harmonized scenarios (BES-SIM). The goals of BES-SIM are (1) to project the global impacts of land-use and climate change on biodiversity and ecosystem services (i.e., nature's contributions to people) over the coming decades, compared to the 20th century, using a set of common metrics at multiple scales, and (2) to identify model uncertainties and research gaps through the comparisons of projected biodiversity and ecosystem services across models. BES-SIM uses three scenarios combining specific Shared Socio-economic Pathways (SSPs) and Representative Concentration Pathways (RCPs)-SSP1xRCP2.6, SSP3xRCP6.0, SSP5xRCP8.6-to explore a wide range of land-use change and climate change futures. This paper describes the rationale for scenario selection, the process of harmonizing input data for land use, based on the second phase of the Land Use Harmonization Project (LUH2), and climate, the biodiversity and ecosystem services models used, the core simulations carried out, the harmonization of the model output metrics, and the treatment of uncertainty. The results of this collaborative modeling project will support the ongoing global assessment of IPBES, strengthen ties between IPBES and the Intergovernmental Panel on Climate Change (IPCC) scenarios and modeling processes, advise the Convention on Biological Diversity (CBD) on its development of a post-2020 strategic plans and conservation goals, and inform the development of a new generation of nature-centred scenarios.

Force-transmitting structures in the digital pads of the tree frog Hyla cinerea : a functional interpretation
Langowski, Julian K.A. ; Schipper, Henk ; Blij, Anne ; Berg, Frank T. van den; Gussekloo, Sander W.S. ; Leeuwen, Johan L. van - \ 2018
Journal of Anatomy 233 (2018)4. - ISSN 0021-8782 - p. 478 - 495.
attachment organ - bioadhesion - collagen - connective tissue - fibre-matrix-composite - material stiffness - shear load - smooth muscle

The morphology of the digital pads of tree frogs is adapted towards attachment, allowing these animals to attach to various substrates and to explore their arboreal habitat. Previous descriptions and functional interpretations of the pad morphology mostly focussed on the surface of the ventral epidermis, and little is known about the internal pad morphology and its functional relevance in attachment. In this study, we combine histology and synchrotron micro-computer-tomography to obtain a comprehensive 3-D morphological characterisation of the digital pads (in particular of the internal structures involved in the transmission of attachment forces from the ventral pad surface towards the phalanges) of the tree frog Hyla cinerea. A collagenous septum runs from the distal tip of the distal phalanx to the ventral cutis and compartmentalises the subcutaneous pad volume into a distal lymph space and a proximal space, which contains mucus glands opening via long ducts to the ventral pad surface. A collagen layer connects the ventral basement membrane via interphalangeal ligaments with the middle phalanx. The collagen fibres forming this layer curve around the transverse pad-axis and form laterally separated ridges below the gland space. The topological optimisation of a shear-loaded pad model using finite element analysis (FEA) shows that the curved collagen fibres are oriented along the trajectories of the maximum principal stresses, and the optimisation also results in ridge-formation, suggesting that the collagen layer is adapted towards a high stiffness during shear loading. We also show that the collagen layer is strong, with an estimated tensile strength of 2.0–6.5 N. Together with longitudinally skewed tonofibrils in the superficial epidermis, these features support our hypothesis that the digital pads of tree frogs are primarily adapted towards the generation and transmission of friction rather than adhesion forces. Moreover, we generate (based on a simplified FEA model and predictions from analytical models) the hypothesis that dorsodistal pulling on the collagen septum facilitates proximal peeling of the pad and that the septum is an adaptation towards detachment rather than attachment. Lastly, by using immunohistochemistry, we (re-)discovered bundles of smooth muscle fibres in the digital pads of tree frogs. We hypothesise that these fibres allow the control of (i) contact stresses at the pad–substrate interface and peeling, (ii) mucus secretion, (iii) shock-absorbing properties of the pad, and (iv) the macroscopic contact geometry of the ventral pad surface. Further work is needed to conclude on the role of the muscular structures in tree frog attachment. Overall, our study contributes to the functional understanding of tree frog attachment, hence offering novel perspectives on the ecology, phylogeny and evolution of anurans, as well as the design of tree-frog-inspired adhesives for technological applications.

Effectief bodembeheer voor een duurzaam watersysteem stroomgebied de Raam : pilot onderzoeksprogramma Lumbricus, pijler bewuste bodem
Schipper, P.N.M. ; Massop, H. ; Kros, H. ; Eekeren, N. van; Zaanen, M. ; Groenendijk, P. ; Goor, S. van; Ros, G.H. - \ 2018
Wageningen : Wageningen Environmental Research (Wageningen Environmental Research rapport 2894) - 49
Ecosysteemdiensten in terreinen van Staatsbosbeheer
Hendriks, Kees ; Schuiling, Rini ; Schipper, Peter ; Bouwma, Irene - \ 2018
Wageningen : Wageningen Environmental Research (Wageningen Environmental Research rapport 2893) - 31
Herkomtst nutriënten Alblasserwaard en Vijfheerenlanden
Boekel, Erwin van; Hendriks, Rob ; Schipper, Peter - \ 2018
Wageningen : Wageningen Environmental Research (Wageningen Environmental Research rapport 2891) - 61
De regionale waterkwaliteit voldoet op veel plaatsen nog niet aan de doelen die voor de Europese Kaderrichtlijn Water zijn gesteld. Een belangrijke oorzaak hiervan is de hoge nutriëntenbelasting. Het generieke mestbeleid zal naar verwachting niet voor 2027 leiden tot de voor de ecologie gewenste verlaging van nutriëntenbelasting. In de Stroomgebiedsbeheerplannen voor de 3e periode (2022-2027) moet Nederland de definitieve keuzes maken over de doelen van de waterlichamen en in te zetten maatregelen. Met name voor de waterlichamen in de Alblasserwaard (Nederwaard en Overwaard) wil Waterschap Rivierenland bij het definitief vaststellen van de doelen en maatregelen goed rekening kunnen houden met de achtergrondbelasting door nutriëntenrijke kwel, stikstofdepositie, mineralisatie en uitloging van veenbodems. In dit onderzoek is de nutriëntenbelasting voor de periode 2004-2013 gekwantificeerd voor de
Nederwaard, Overwaard en het aangrenzende afwateringsgebied vijfheerenlanden. Met de methodiek ECHO zijn voor het kwantificeren van de uit- en afspoeling van nutriënten de rekenplots van het landelijk modelinstrumentarium STONE regiospecifieker toebedeeld op basis van actuele informatie over het landgebruik, bodemtype en de grondwaterstanden. Per gebied zijn de hoeveelheden inlaatwater en uitgemalen water gekwantificeerd (watervolume en nutriëntenvrachten) op basis van de meetdata en regiospecifieke kennis die het Waterschap voor het onderzoek heeft aangedragen. De belasting met nutriënten vanuit overige bronnen zijn ontleend aan de EmissieRegistratie. Na kwantificering en validatie van de berekende waterbalansen en nutriëntenbalansen is de belasting onderverdeeld naar de bronnen van herkomst. Uit het onderzoek blijkt dat de totale nutriëntenbelasting van het oppervlaktewater voornamelijk wordt bepaald door de uit- en afspoeling uit landbouwgronden (83 à 95%). Voor stikstof levert de actuele bemesting het grootste aandeel (Nederwaard 38%, Overwaard 42%, Vijfheerenlanden 55%), gevolgd door de nalevering vanuit landbouwgronden (respectievelijk 20%, 17% en 8%). Met het modelinstrumentarium zijn de effecten van het 5e Nitraat Actie Programma op de uit- en afspoeling van nutriënten berekend. Evenals de landelijke evaluatie komt hieruit naar voren dat het effect hiervan op de nutriëntenbelasting in de beschouwde gebieden gering is (kleiner dan 5%).
Fysisch-chemische inductie van systemic acquired resistance (SAR): elicitors & stuurlicht
Stevens, L.H. ; Breeuwsma, S.J. ; Rutgers, B. ; Griekspoor, Y. ; Noordam, Marianne ; Vos, C.H. de; Schipper, A. ; Leiss, K.A. - \ 2018
Severe interpersonal violence against children in sport : Associated mental health problems and quality of life in adulthood
Vertommen, Tine ; Kampen, Jarl ; Schipper-van Veldhoven, Nicolette ; Uzieblo, Kasia ; Eede, Filip Van Den - \ 2018
Child Abuse and Neglect 76 (2018). - ISSN 0145-2134 - p. 459 - 468.
Abuse - Child maltreatment - Long-term consequences - Psychological symptoms - Sequelae - Youth sport
In a recent large-scale prevalence study of interpersonal violence (IV) against child athletes in the Netherlands and Belgium we found that 9% of adult respondents who participated in organized sports before the age of 18 had experienced severe psychological violence, 8% severe physical violence, and 6% severe sexual violence in various sport settings. While the general literature has repeatedly shown that exposure to IV during childhood is associated with mental health problems in adulthood and to a lesser extent with reduced quality of life (QOL), these relationships have not been demonstrated in (former) athletes. Thus, the current study aims to assess the association of severe childhood IV in sport and adult wellbeing. Depression, anxiety, and somatization were assessed in the same general population sample (N = 4043) using the Brief Symptom Inventory (BSI-18) and QOL with the World Health Organization Quality of Life questionnaire (WHOQOL-Brèf). The association between severe IV in sport and adult wellbeing was investigated using multiple linear regression while controlling for demographics, recent life events, and relatives’ psychological problems. We found severe sexual, physical, and psychological childhood IV in sport to be associated with more adult psychological distress and reduced QOL. Polyvictimization shows the strongest correlation with poorer wellbeing and QOL. Recent life events, relatives’ psychological problems, marital status, and level of education were significant covariates in the psychological symptoms and QOL assessed. We hope that these new insights prompt sport administrators to implement broad spectrum child protection measures and raise the awareness of mental health professionals about the necessity to also screen for adverse childhood experiences in the sport context.
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