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Wageningen, Netherlands

Wageningen University and Research Centre is a Dutch public university in Wageningen, Netherlands. It consists of Wageningen University and the former agricultural research institutes ) of the Dutch Ministry of Agriculture. Wageningen UR trains specialists in life science and focuses its research on scientific, social and commercial problems in the field of life science and natural resources. In the field of agricultural science, the university is considered world-class. Wikipedia.

Van Vuuren D.P.,Netherlands Environmental Assessment Agency PBL | Bouwman A.F.,Netherlands Environmental Assessment Agency PBL | Bouwman A.F.,Wageningen University | Beusen A.H.W.,Netherlands Environmental Assessment Agency PBL
Global Environmental Change | Year: 2010

The phosphorus (P) cycle has been significantly altered by human activities. For this paper, we explored the sustainability of current P flows in terms of resource depletion and the ultimate fate of these flows. The analysis shows that rapid depletion of extractable phosphate rock is not very likely, in the near term. Under best estimates, depletion would be around 20-35%. In worst case scenarios, about 40-60% of the current resource base would be extracted by 2100. At the same time, production will concentrate in Asia, Africa and West Asia, and production costs will likely have increased. As there are no substitutes for phosphorus plant nutrients in agriculture, arguably even partial depletion of P resources may in the long run be relevant for the sustainability of agriculture. Consumption trends lead to large flows of phosphorus to surface water and a considerable build-up of phosphorus in agricultural soils in arable lands. This may allow a reduction in future P fertiliser application rates in crop production. Results also indicate a global depletion of P pools in soils under grassland, which may be a threat to ruminant production. © 2010 Elsevier Ltd. Source

Gupta A.,Wageningen University
Global Environmental Politics | Year: 2010

This article explores the prospects for transparency to be a transformative force in global biosafety governance. It analyzes whether information disclosure can further a right to know and choose, and hence facilitate oversight over transnational transfers of genetically modified organisms (GMOs). It examines the question of "Whose right to know what and why?" with regard to GMOs in the agricultural commodity trade in relation to the global Cartagena Protocol on Biosafety. I argue that the limited disclosure obligations in this global context follow rather than shape market developments, and that complex infrastructures of sampling, testing and detection are required to put disclosed information to use. If so, rather than a normative right-to-know of importing countries, a competing norm of caveat emptor (let the buyer beware) prevails. I conclude that the potential of transparency to empower remains unrealized, particularly for the poorest countries most reliant on globally-induced disclosure. © 2010 by the Massachusetts Institute of Technology. Source

Duit A.,University of Stockholm | Feindt P.H.,Wageningen University | Meadowcroft J.,Carleton University
Environmental Politics | Year: 2016

‘Bringing the state back in’ to research on comparative, inter-, and trans-national environmental politics and policy will contribute to better understanding of the limits and prospects of contemporary approaches to environmental politics and the overall evolution of contemporary states once environmental issues become central. The rationale for the state as an analytical perspective in environmental policy and politics is explained, and an empirically oriented concept of the environmental state is introduced, along with a tentative sketch of its evolution in historical perspective. A research agenda on the environmental state is mapped out, centring around variation and convergence in environmental states across space and time; the political/economic dynamics of contemporary environmental states; and inter-linkages among environmental problems, the constitution of political communities, and the functioning of the public power. In conclusion, the ways in which the contributions to this volume address that research agenda are introduced. © 2015 Taylor & Francis. Source

Herold M.,Wageningen University | Skutsch M.,National Autonomous University of Mexico
Environmental Research Letters | Year: 2011

Different options have been suggested by Parties to the UNFCCC (United Framework Convention on Climate Change) for inclusion in national approaches to REDD and REDD + (reduced deforestation, reduced degradation, enhancement of forest carbon stocks, sustainable management of forest, and conservation of forest carbon stocks). This paper proposes that from the practical and technical points of view of designing action for REDD and REDD + at local and sub-national level, as well as from the point of view of the necessary MRV (monitoring, reporting and verification), these should be grouped into three categories: conservation, which is rewarded on the basis of no changes in forest stock, reduced deforestation, in which lowered rates of forest area loss are rewarded, and positive impacts on carbon stock changes in forests remaining forest, which includes reduced degradation, sustainable management of forest of various kinds, and forest enhancement. Thus we have moved degradation, which conventionally is grouped with deforestation, into the forest management group reported as areas remaining forest land, with which it has, in reality, and particularly as regards MRV, much more in common. Secondly, in the context of the fact that REDD/REDD + is to take the form of a national or near-national approach, we argue that while systematic national monitoring is important, it may not be necessary for REDD/REDD + activities, or for national MRV, to be started at equal levels of intensity all over the country. Rather, areas where interventions seem easiest to start may be targeted, and here data measurements may be more rigorous (Tier 3), for example based on stakeholder self-monitoring with independent verification, while in other, untreated areas, a lower level of monitoring may be pursued, at least in the first instance. Treated areas may be targeted for any of the three groups of activities (conservation, reduced deforestation, and positive impact on carbon stock increases in forest remaining forest). © 2011 IOP Publishing Ltd. Source

Korthals M.,Wageningen University
American Journal of Clinical Nutrition | Year: 2011

To optimize the coevolution of nutrigenomics and society (ie, the reciprocal stimulation of both developments), I analyzed chances for a fruitful match between normative concepts and strategies of both developments. Nutrigenomics embodies ≥3 normative concepts. First, food is exclusively interpreted in terms of disease prevention. Second, striving for health is interpreted as the quantification of risks and prevention of diseases through positive food-gene interactions. The third normative idea is that disease prevention by the minimization of risks is an individual's task. My thesis was that these concepts of nutrigenomics would not easily match with concepts of food and health of various food styles in Western societies, which, for instance, parents in the case of metabolic programming endorse and with a philosophical view of the relation between food, health, and the meaning of life. Next, I reflected on the nonsynchronized coevolution of nutrigenomics and society because of this mismatch and introduced the concept of the fair representation of food styles in nutrigenomic developments. To synchronize and optimize the coevolution of nutrigenomics and society, I propose that the research policy of nutrigenomics should change to a research partnership with society on the basis of fair representation. © 2011 American Society for Nutrition. Source

Sosef M.S.M.,Wageningen University
Plant Ecology and Evolution | Year: 2013

Background and aims - The genus Idertia belongs to the subfamily Ochnoideae, tribe Ochneae, subtribe Ouratinae. This paper aims at a full taxonomic revision and a critical evaluation of the taxonomic position of the genus along with its diagnostic characters. Methods - All characters are studied using 73 herbarium collections of the following herbaria: B, BM, BR, BRLU, COI, EA, G, K, MO, P and WAG. Specimen data were managed using the BRAHMS herbarium management software. Key results - Idertia is characterized by a gynobasic style, apocarpous fruits, ten stamens, persistent and accrescent sepals and intra-axillary fused stipules. It shares these features with its African relatives Campylospermum and Rhabdophyllum, but its axillary inflorescence, smooth anthers and straight cotyledons renders it distinct. The latter feature is reminiscent of the South American relative Ouratea which lacks the persistent sepals and has free lateral stipules. Other diagnostic characters of the wood, leaves, inflorescence, flowers and fruits are discussed. A key to the four genera of the subtribe Ouratinae is provided. The correct author combination for the name Ouratinae is (Engl.) Kanis. The variation amongst the four species of Idertia recognized by other authors was studied carefully and deemed continuous. Only a single, though variable species distributed from Guinea to Uganda is recognized. A full taxonomic treatment is provided and two lectotypes are designated. Conclusions - Idertia is a well-defined and sufficiently distinct monotypic genus. © National Botanic Garden of Belgium and Royal Botanical Society of Belgium. Source

Groeneveld R.A.,Wageningen University
Ecological Economics | Year: 2010

This paper addresses the problem of selecting reserve sites cost-effectively, taking into account the mobility and habitat area requirements of each species. Many reserve site selection problems are analyzed in mixed-integer linear programming (MILP) models due to the mathematical solvers available for this model type. Ideally, such reserve site selection models take into consideration the possibility that species use reserve sites, even small ones, as stepping stones to move from one site to another. This consideration, however, is difficult to include in MILP models. This paper demonstrates and evaluates three alternative MILP models that include species' mobility and habitat area requirements. All models include the possible stepping stone function of reserve sites to some extent, although none does so perfectly. The models demonstrated find spatial reserve networks at lower costs than a non-spatial reserve site selection model. © 2010 Elsevier B.V. Source

Berton-Carabin C.C.,Wageningen University | Ropers M.-H.,French National Institute for Agricultural Research | Genot C.,French National Institute for Agricultural Research
Comprehensive Reviews in Food Science and Food Safety | Year: 2014

More polyunsaturated fats in processed foods and fewer additives are a huge demand of public health agencies and consumers. Consequently, although foods have an enhanced tendency to oxidize, the usage of antioxidants, especially synthetic antioxidants, is restrained. An alternate solution is to better control the localization of reactants inside the food matrix to limit oxidation. This review establishes the state-of-the-art on lipid oxidation in oil-in-water (O/W) emulsions, with an emphasis on the role of the interfacial region, a critical area in the system in that respect. We first provide a summary on the essential basic knowledge regarding (i) the structure of O/W emulsions and interfaces and (ii) the general mechanisms of lipid oxidation. Then, we discuss the factors involved in the development of lipid oxidation in O/W emulsions with a special focus on the role played by the interfacial region. The multiple effects that can be attributed to emulsifiers according to their chemical structure and their location, and the interrelationships between the parameters that define the physicochemistry and structure of emulsions are highlighted. This work sheds new light on the interpretation of reported results that are sometimes ambiguous or contradictory. © 2014 Institute of Food Technologists®. Source

Derkzen P.,Wageningen University
European Urban and Regional Studies | Year: 2010

In recent years partnership has become an established aspect of rural development across rural Europe. Both Wales and the Netherlands have seen similar trends towards more decentralized and territorial modes of rural governance in which policy networks of governmental and societal actors work together at a local or regional level to further rural development. Such networks are called 'partnerships' in English and 'gebiedscommissies' in Dutch. This paper addresses differences in the composition and organization of rural partnerships in these two countries and attributes the differences between them to the policy context in each country. Four policy factors are identified as contributing to the specific approach to partnership adopted in the two countries.The review sustains the presumption that in Dutch rural partnerships the integration discourse is more important than the participation discourse, which is more prominent in Wales. © The Author(s), 2010. Source

Mol A.P.J.,Wageningen University
Environmental Politics | Year: 2010

The current generation of crop-based biofuels is heavily contested for its negative consequences for the environment and the poor. Hence, the current biofuel system needs to be transformed in the direction of what can be labelled 'fair fuels': (bio)fuels that are environmentally and socially sustainable. Conventional state environmental authorities have limited power and legitimacy to effectively regulate the sustainability of current global biofuels. Hence, we witness the emergence of private market environmental authorities, moral environmental authorities and all kinds of hybrid authorities in biofuel regulation. These new forms of environmental authority should neither be condemned as ineffective and undemocratic nor celebrated as the modern answer to transnational environmental problems that face state failure. Further critical inquiry into the changing environmental authority structure under conditions of globalisation is needed. © 2010 Taylor & Francis. Source

Gupta A.,Wageningen University
Environment and Planning C: Government and Policy | Year: 2010

Although transparency is a key concept in the social sciences, it remains an understudied phenomenon in global environmental governance. This paper analyzes effectiveness of 'governance by transparency' or governance by information disclosure as a key innovation in global environmental and risk governance. Information disclosure is central to current efforts to govern biosafety or safe trade in genetically modified organisms (GMOs). Through analyzing the dynamics of GMO-related information disclosure to the global Biosafety Clearing House (BCH), I argue that the originally intended normative and procedural aims of disclosure in this caseo-to facilitate a GMO-importing country's right to know and right to choose prior to trade in GMOso-are not yet being realized, partly because the burden of BCH disclosure currently rests, ironically, on importing countries. As a result, BCH disclosure may even have market-facilitating rather than originally intended market-regulating effects with regard to GMO trade, turning on its head the intended aims of governance by disclosure. © 2010 Pion Ltd and its Licensors. Source

Groeneveld R.A.,Wageningen University
ICES Journal of Marine Science | Year: 2011

Fisheries policy is most effective when supported by fishers and the general public. Dutch citizens and fishers support for a selection of policy alternatives to enhance the sustainability of the Dutch North Sea cutter fleet is estimated, and the same groups support for policy alternatives is expressed in monetary terms. A stated-choice survey was held among a representative sample of the Dutch population to assess their average willingness to pay for a selection of policy objectives, and among Dutch flatfish fishers to estimate their willingness to accept a selection of policy measures. The results indicate that citizens are most concerned about the impact of beam trawling on benthic megafauna, because they are on average willing to pay €21.46 per year to reduce the impact, but reducing fishing pressure in the plaice (Pleuronectes platessa) spawning period and restoring spawning-stock biomass of plaice and sole (Solea solea) to the levels of maximum sustainable yield are also supported. Fishers seem to support enhanced fines for the use of illegal fishing gear, but they are most opposed to increasing the minimum landing size of sole. © 2011 International Council for the Exploration of the Sea. Published by Oxford Journals. All rights reserved. Source

Van der Ploeg J.D.,Wageningen University
Journal of Agrarian Change | Year: 2010

This paper argues that the food crisis cannot solely be equated with abrupt food price increases or seen as merely market induced. The unprecedented price increases of the first half of 2008, and the extremely low prices that followed, are expressions of a far wider and far more persistent underlying crisis, which has been germinating for more than a decade. It is the complex outcome of several combined processes, including the industrialization of agriculture, the liberalization of food and agricultural markets and the rise of food empires. The interaction of these processes has created a global agrarian crisis that has provoked the multifaceted food crisis. Both these crises are being accelerated through their interactions with the wider economic and financial crisis. © 2010 The Author - Journal compilation © 2010 Blackwell Publishing Ltd. Source

Koornneef M.,Max Planck Institute for Plant Breeding Research | Koornneef M.,Wageningen University | Meinke D.,Oklahoma State University
Plant Journal | Year: 2010

Summary Twenty-five years ago, Arabidopsis thaliana emerged as the model organism of choice for research in plant biology. A consensus was reached about the need to focus on a single organism to integrate the classical disciplines of plant science with the expanding fields of genetics and molecular biology. Ten years after publication of its genome sequence, Arabidopsis remains the standard reference plant for all of biology. We reflect here on the major advances and shared resources that led to the extraordinary growth of the Arabidopsis research community. We also underscore the importance of continuing to expand and refine our detailed knowledge of Arabidopsis while seeking to appreciate the remarkable diversity that characterizes the plant kingdom. © 2010 Blackwell Publishing Ltd. Source

Van der Sman R.G.M.,Wageningen University
Food Hydrocolloids | Year: 2013

The moisture sorption of ternary mixtures of biopolymer, sugar and water is investigated by means of the Free-Volume-Flory-Huggins (FVFH) theory. The earlier FVFH theory developed for binary mixtures of biopolymer/water and sugar/water has to be modified to account for two effects: 1) the change in the glass temperature due to the non-ideal mixing of biopolymer and 2) inhibition of self-association of the polymer if the mixture is quenched very fast into the glassy state. The modified FVFH theory forms a good basis for predicting moisture sorption for quaternary mixtures of biopolymers, di-, mono-saccharides and water - which can be viewed as a model for vegetables and fruits. © 2013 Elsevier Ltd. Source

Gupta A.,Wageningen University
Global Environmental Politics | Year: 2010

This introductory article draws on the contributions to this special issue to consider the implications of a transparency turn in global environmental and sustainability governance. Three interrelated aspects are addressed: why transparency now? How is transparency being institutionalized? And what effects does it have? In analyzing the spread of transparency in governance, the article highlights the broader (contested) normative context that shapes both its embrace by various actors and its institutionalization. I argue that the effects of transparency-whether it informs, empowers or improves environmental performance-remain uneven, with transparency falling short of meeting the ends many anticipate from it. Nonetheless, as the contributions to this issue make clear, transparency has indeed come of age as a defining feature of our current and future politics. © 2010 by the Massachusetts Institute of Technology. Source

Rodela R.,Wageningen University | Rodela R.,University of Nova Gorica
Environmental Science and Policy | Year: 2013

The literature on social learning advances a critique to the command-and-control approach to resource management, and often, this critique is made by borrowing insights and ideas from disciplines other than resource management, which led to certain conceptual and methodological turns that now characterise the social learning discourse. This paper is based on an extensive survey of the social learning literature; ninety-seven studies were reviewed and classified by the type of natural resource, its geographical location, type of application and related aspects, which helped to identify some general trends. Disciplinary influences that contributed to shape the research are analysed and discussed. The findings suggest that social learning research is issue-driven and that some types of natural resources and geographical areas prevail over others. This study finds that deliberative democracy, pedagogy and research of complex adaptive systems have contributed the most to shaping the current conceptual base of the discourse. Interdisciplinary engagement, as well as choices in terms of what has been borrowed and how the borrowed concepts have been used, help to explain the heterogeneity of frameworks and definitions in the social learning literature. © 2012 Elsevier Ltd. Source

van Huis A.,Wageningen University
Proceedings of the Nutrition Society | Year: 2016

The global increase in demand for meat and the limited land area available prompt the search for alternative protein sources. Also the sustainability of meat production has been questioned. Edible insects as an alternative protein source for human food and animal feed are interesting in terms of low greenhouse gas emissions, high feed conversion efficiency, low land use, and their ability to transform low value organic side streams into high value protein products. More than 2000 insect species are eaten mainly in tropical regions. The role of edible insects in the livelihoods and nutrition of people in tropical countries is discussed, but this food source is threatened. In the Western world, there is an increasing interest in edible insects, and examples are given. Insects as feed, in particular as aquafeed, have a large potential. Edible insects have about the same protein content as conventional meat and more PUFA. They may also have some beneficial health effects. Edible insects need to be processed and turned into palatable dishes. Food safety may be affected by toxicity of insects, contamination with pathogens, spoilage during conservation and allergies. Consumer attitude is a major issue in the Western world and a number of strategies are proposed to encourage insect consumption. We discuss research pathways to make insects a viable sector in food and agriculture: an appropriate disciplinary focus, quantifying its importance, comparing its nutritional value to conventional protein sources, environmental benefits, safeguarding food safety, optimising farming, consumer acceptance and gastronomy. Copyright © The Author 2016 Source

Kitajima K.,University of Florida | Kitajima K.,Smithsonian Tropical Research Institute | Poorter L.,Wageningen University | Poorter L.,Instituto Boliviano Of Investigacion Forestal
New Phytologist | Year: 2010

•Leaf toughness is thought to enhance physical defense and leaf lifespan. Here, we evaluated the relative importance of tissue-level leaf traits vs lamina thickness, as well as their ontogenetic changes, for structure-level leaf toughness and regeneration ecology of 19 tropical tree species.•We measured the fracture toughness of the laminas and veins of sapling leaves with shearing tests, and used principal component analysis and structural equation modeling to evaluate the multivariate relationships among traits that contribute to leaf toughness and their links to ecological performance traits.•Tissue traits (density and fracture toughness of lamina and vein) were correlated positively with each other, but independent of lamina thickness. The tissue traits and lamina thickness contributed additively to the structure-level toughness (leaf mass per area and work-to-shear). Species with dense and tough leaves as saplings also had dense and tough leaves as seedlings and adults. The patterns of ontogenetic change in trait values differed between the seedling-to-sapling and sapling-to-adult transitions.•The fracture toughness and tissue density of laminas and veins, but not the lamina thickness, were correlated positively with leaf lifespan and sapling survival, and negatively with herbivory rate and sapling regeneration light requirements, indicating the importance of tissue-level leaf traits. © The Authors (2010). Journal compilation © New Phytologist Trust (2010). Source

van der Laan L.N.,University Utrecht | de Ridder D.T.D.,University Utrecht | Viergever M.A.,University Utrecht | Smeets P.A.M.,University Utrecht | Smeets P.A.M.,Wageningen University
NeuroImage | Year: 2011

Food selection is primarily guided by the visual system. Multiple functional neuro-imaging studies have examined the brain responses to visual food stimuli. However, the results of these studies are heterogeneous and there still is uncertainty about the core brain regions involved in the neural processing of viewing food pictures. The aims of the present study were to determine the concurrence in the brain regions activated in response to viewing pictures of food and to assess the modulating effects of hunger state and the food's energy content.We performed three Activation Likelihood Estimation (ALE) meta-analyses on data from healthy normal weight subjects in which we examined: 1) the contrast between viewing food and nonfood pictures (17 studies, 189 foci), 2) the modulation by hunger state (five studies, 48 foci) and 3) the modulation by energy content (seven studies, 86 foci).The most concurrent brain regions activated in response to viewing food pictures, both in terms of ALE values and the number of contributing experiments, were the bilateral posterior fusiform gyrus, the left lateral orbitofrontal cortex (OFC) and the left middle insula. Hunger modulated the response to food pictures in the right amygdala and left lateral OFC, and energy content modulated the response in the hypothalamus/ventral striatum.Overall, the concurrence between studies was moderate: at best 41% of the experiments contributed to the clusters for the contrast between food and nonfood. Therefore, future research should further elucidate the separate effects of methodological and physiological factors on between-study variations. © 2010 Elsevier Inc. Source

Rodela R.,Wageningen University
Ecology and Society | Year: 2011

A review is presented of research contributions that use social learning in research on natural resource management. The review is based on an extensive survey of peer-reviewed journal articles appraised against the following selected analytical items: (1) characterizing features, (2) level of analysis, and (3) operational measures. Together, these allowed for an assessment of underlying assumptions and emerging themes. The findings suggest that, within natural resource management literature, three research approaches to social learning have been developed, each with its own assumptions about the learning process, learning outcomes, and operational practices. Hence, we find that a group of publications showed an interest for participants' learning experiences and focused on the type of outcomes that arise from their attendance in participatory workshops and similar activities. Also, findings indicate that a second group of publications showing an interest for learning in other types of settings, such as groups, networks, and associations, have framed social learning as a process that results in a change in resource management practices, or in how things are done. On the other hand, a third group of publications showed an interest in social-ecological systems emphasizing learning as an emergent property. © 2011 by the author(s). Source

Peters K.,Wageningen University
Leisure Sciences | Year: 2010

Western countries are facing serious political issues regarding integration and social cohesion in multicultural societies and migration. Dutch society is engaged with these issues in the context of current racial tensions and conflicts. The government recently introduced policy measures to foster interactions between Dutch natives and ethnic migrant groups to promote integration. This research explores the extent and nature of interethnic interactions by focusing on leisure activities in the public spaces of ethnically mixed neighborhoods. Observations and semi-structured interviews are used to gather information about the interactions in and the meaning of urban public spaces. Results show that although not many interethnic interactions occurred, people from various ethnic backgrounds valued being together in parks. © Taylor & Francis Group, LLC. Source

Buchanan K.S.,Wageningen University
Environmental Science and Policy | Year: 2013

This paper explores how multiple types of knowledge - epistemic, technical, and anecdotal - are combined and used discursively within the claim-making process of a long-running socio-environmental conflict concerning copper extraction and its threat to biodiversity conservation in Ecuador's Intag valley cloud-forest. The contentions at play in this highly polarised dispute are broadly speaking either developmental or environmental in nature. This article examines the forms of knowledge that are mobilised in environmental discourse and the ways in which claim-makers deploy different types of knowledge to advance their political and policy interests. It contends that the success of the environmental claim-makers in protecting the cloud-forest so far derives from their political mobilisation around strategic and dynamic combinations of different types of environmental knowledge. Through including the hegemonic neoliberal biodiversity discourse in their anti-mining and pro-conservation environmental discourse and policy advocacy, environmentalists from the local to the global level were able to use neoliberal arguments as counter-claims against the neoliberal pro-extractives rhetoric of economic development. In practice, this was achieved both by enacting local environmental policies and practices to protect the Intag area from large-scale open-cast mining activities, and by leveraging power through spreading social media based information to undermine the viability of successive mining concession-owners at the international level. The gap between science and policy therefore was, and continues to be, transcended by the nature of the urgent political expediency of the conflict. © 2013 Elsevier Ltd. Source

Kodger T.E.,Harvard University | Sprakel J.,Wageningen University
Advanced Functional Materials | Year: 2013

Efficient use of (nano)particle self-assembly for creating nanostructured materials requires sensitive control over the interactions between building blocks. Here, a very simple method for rendering the interactions between almost any hydrophobic nano- and microparticles thermoswitchable is described and this attraction is characterized using colloid probe atomic force microscopy (CP-AFM). In a single-step synthesis, a thermoresponsive surfactant is prepared that through physical adsorption generates a thermosensitive brush on hydrophobic surfaces. These surface layers can reversibly trigger gelation and crystallization of nano- and microparticles, and at the same time can be used to destabilize emulsions on demand. The method requires no chemical surface modification yet is universal, reproducible, and fully reversible. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Chaves L.F.,Emory University | Koenraadt C.J.M.,Wageningen University
Quarterly Review of Biology | Year: 2010

In recent decades, malaria has become established in zones at the margin of its previous distribution, especially in the highlands of East Africa. Studies in this region have sparked a heated debate over the importance of climate change in the territorial expansion of malaria, where positions range from its neglect to the reification of correlations as causes. Here, we review studies supporting and rebutting the role of climatic change as a driving force for highland invasion by malaria. We assessed the conclusions from both sides of the argument and found that evidence for the role of climate in these dynamics is robust. However, we also argue that over-emphasizing the importance of climate is misleading for setting a research agenda, even one which attempts to understand climate change impacts on emerging malaria patterns. We review alternative drivers for the emergence of this disease and highlight the problems still calling for research if the multidimensional nature of malaria is to be adequately tackled. We also contextualize highland malaria as an ongoing evolutionary process. Finally, we present Schmalhausen's law, which explains the lack of resilience in stressed systems, as a biological principle that unifies the importance of climatic and other environmental factors in driving malaria patterns across different spatio-temporal scales. Copyright © 2010 by The University of Chicago Press. All rights reserved. Source

Warner J.,Wageningen University
International Journal of Sustainable Society | Year: 2012

The present contribution will argue that 'water wars' and 'water peace' are not objective 'facts' but narratives reflecting competing world views. The two narratives are lenses shedding different lights on the same phenomenon. In addition to the narratives underlying the water-peace debate a third narrative can be adduced, that has a different, critical perspective on water wars, that has a very different interpretation of water conflict, looking at how local forces express global hegemonic struggles. Each of these has a different and credible account on why there has been no violence between states, and the role of hegemons and regimes in this. This paper pays special attention to regime formation. While the neo-realist and liberal-institutionalist schools have seen a gradual approximation since the 1980s (the neo-neo-consensus) they have different views of international regime cooperation and its drivers, notably the stabilising role of hegemons. The third, critical narrative again revives a different, underexposed strand in regimes analysis. Since 'regimes begin at home' (Waterbury, 2002), this paper also looks at the internal dynamics in Egypt. © 2012 Inderscience Enterprises Ltd. Source

Mol A.P.J.,Wageningen University
Environmental Development | Year: 2012

After initial debates and controversies, from the late 1980s onwards market instruments became fully accepted in environmental governance. However, with their inclusion in transnational and global environmental governance, market institutions seem to be in for a new round of discussions. Transnational carbon markets stand out in these debates, especially since the recent financial crisis made the world aware of the vulnerability of global financial markets. This paper uses a sociology of flows perspective to review current debates on the emerging global carbon markets as new - initially state-created - institutions to mitigate climate change. Do carbon markets aim primarily at climate change mitigation or mainly at financial gains? Who controls the functioning and outcome of these transnational carbon markets? And is there a risk of a global carbon market crisis, not unlike the global financial crisis? The paper concludes that current discussions and decisions on carbon market architectures are conducive for the future role of carbon markets in climate change mitigation. States are just one of the many actors shaping carbon markets and thus managing carbon flows. © 2012 Elsevier B.V. Source

Artur L.,Eduardo Mondlane University | Hilhorst D.,Wageningen University
Global Environmental Change | Year: 2012

This paper analyzes discourses and practices of flood response and adaptation to climate change in Mozambique. It builds on recent publications on climate change adaptation that suggest that the successes and failures of adaptation highly depend on the cultural and political realms of societal perceptions and the sensitivity of institutions. To capture this, the paper adopted a multi-sited ethnographic approach. Acknowledging that there is no central locus of representation that can unveil the working of disaster response in Mozambique, the paper brings together five vignettes of research in different 'sites' of concern to the rise in floods in Mozambique. These are the politics of climate change adaptation at the national institutional level, societal responses to increased flooding, local people's responses to floods, the evacuation and resettlement programme following the 2007 flood. The paper finds how adaptation to climate change becomes part of everyday politics, how actors aim to incorporate responses into the continuation of their normal behavior and how elites are better positioned to take advantage of adaptation programmes than the vulnerable people that were targeted. It argues that climate change adaptation must be made consonant with historically grown and ongoing social and institutional processes. It concludes with lessons that the analysis and methodology of the research can provide for the practice of climate change adaptation. © 2011 Elsevier Ltd. Source

Heijman W.,Wageningen University
NJAS - Wageningen Journal of Life Sciences | Year: 2016

This paper focuses on the size of the Dutch bio-economy. With the help of consolidated input-output tables, the size of the bio-economy in terms of value added is estimated for the years 2008-2012. It appears that in the Netherlands, during the period indicated, its share in national production slowly rose from 6.7% in 2008-7.2% in 2012. © 2016 Royal Netherlands Society for Agricultural Sciences. Published by Elsevier B.V. All rights reserved. Source

van Vliet B.J.M.,Wageningen University
Journal of Environmental Policy and Planning | Year: 2012

Network-bound systems are crucial in environmental governance as the usage of their services embody significant environmental impacts. Conditions for network-bound systems providing services to consumers have altered dramatically over the last decades. Liberalization and privatization have led to a differentiation in providers, technologies, products and services, very a-typical for sectors that were formerly characterized by public and uniform modes of provision and consumption. The paper gives an overview of what the socio-technical differentiation of network-bound systems and services imply for end-users and how new relations emerge between users and providers of water and electricity services. Drawing upon contemporary theory development in science and technology studies and in environmental sociology, the paper presents recent empirical findings of differentiation and innovation in drinking water supply, waste water management and electricity supply in the Netherlands. From these developments, the paper concludes that sustainable innovation in network-bound systems leads to a differentiation of not only resources, providers and technologies but also of consumer roles towards provision and use of water and energy services in various ways. Considering that those diverse services are combined in consumers' social practices, a plea is made for a practice-inclusive perspective on understanding and enhancing sustainable innovation in network-bound systems. © 2012 Copyright Taylor and Francis Group, LLC. Source

Hanssen I.M.,Scientia Terrae Research Institute | Thomma B.P.H.J.,Wageningen University
Molecular Plant Pathology | Year: 2010

Taxonomy: Pepino mosaic virus (PepMV) belongs to the Potexvirus genus of the Flexiviridae family. Physical properties: PepMV virions are nonenveloped flexuous rods that contain a monopartite, positive-sense, single-stranded RNA genome of 6.4 kb with a 3′ poly-A tail. The genome contains five major open reading frames (ORFs) encoding a 164-kDa RNA-dependent RNA polymerase (RdRp), three triple gene block proteins of 26, 14 and 9 kDa, and a 25-kDa coat protein. Genome diversity: Four PepMV genotypes, with an intergenotype RNA sequence identity ranging from 78% to 95%, can be distinguished: the original Peruvian genotype (LP); the European (tomato) genotype (EU); the American genotype US1; and the Chilean genotype CH2. Transmission: PepMV is very efficiently transmitted mechanically, and a low seed transmission rate has been demonstrated. In addition, bumblebees have been associated with viral transmission. Host range: Similar to other Potexviruses, PepMV has a rather narrow host range that is thought to be largely restricted to species of the Solanaceae family. After originally being isolated from pepino (Solanum muricatum), PepMV has been identified in natural infections of the wild tomato species S. chilense, S. chmielewskii, S. parviflorum and S. peruvianum. PepMV is causing significant problems in the cultivation of the glasshouse tomato Solanum lycopersicum, and has been identified in weeds belonging to various plant families in the vicinity of tomato glasshouses. Symptomatology: PepMV symptoms can be very diverse. Fruit marbling is the most typical and economically devastating symptom. In addition, fruit discoloration, open fruit, nettle-heads, leaf blistering or bubbling, leaf chlorosis and yellow angular leaf spots, leaf mosaic and leaf or stem necrosis have been associated with PepMV. The severity of PepMV symptoms is thought to be dependent on environmental conditions, as well as on the properties of the viral isolate. Minor nucleotide sequence differences between isolates from the same genotype have been shown to lead to enhanced aggressiveness and symptomatology. Control: Prevention of infection through strict hygiene measures is currently the major strategy for the control of PepMV in tomato production. Cross-protection can be effective, but only under well-defined and well-controlled conditions, and the effectiveness depends strongly on the PepMV genotype. © 2009 Blackwell Publishing Ltd. Source

Fleer G.J.,Wageningen University
Advances in Colloid and Interface Science | Year: 2010

This review is an extended version of the Overbeek lecture 2009, given at the occasion of the 23rd Conference of ECIS (European Colloid and Interface Society) in Antalya, where I received the fifth Overbeek Gold Medal awarded by ECIS. I first summarize the basics of numerical SF-SCF: the Scheutjens.Fleer version of Self-Consistent-Field theory for inhomogeneous systems, including polymer adsorption and depletion. The conformational statistics are taken from the (non-SCF) DiMarzio.Rubin lattice model for homopolymer adsorption, which enumerates the conformational details exactly by a discrete propagator for the endpoint distribution but does not account for polymer.solvent interaction and for the volume-filling constraint. SF-SCF corrects for this by adjusting the field such that it becomes self-consistent. The model can be generalized to more complex systems: polydispersity, brushes, random and block copolymers, polyelectrolytes, branching, surfactants, micelles, membranes, vesicles, wetting, etc. On a mean-field level the results are exact; the disadvantage is that only numerical data are obtained. Extensions to excluded-volume polymers are in progress. Analytical approximations for simple systems are based upon solving the Edwards diffusion equation. This equation is the continuum variant of the lattice propagator, but ignores the finite segment size (analogous to the Poisson.Boltzmann equation without a Stern layer). By using the discrete propagator for segments next to the surface as the boundary condition in the continuum model, the finite segment size can be introduced into the continuum description, like the ion size in the Stern.Poisson.Boltzmann model. In most cases a ground-state approximation is needed to find analytical solutions. In this way realistic analytical approximations for simple cases can be found, including depletion effects that occur in mixtures of colloids plus non-adsorbing polymers. In the final part of this review I discuss a generalization of the free-volume theory (FVT) for the phase behavior of colloids and non-adsorbing polymer. In FVT the polymer is considered to be ideal: the osmotic pressure Π follows the Van 't Hoff law, the depletion thickness δ equals the radius of gyration. This restricts the validity of FVT to the so-called colloid limit (polymer much smaller than the colloids). We have been able to find simple analytical approximations for Π and δ which account for non-ideality and include established results for the semidilute limit. So we could generalize FVT to GFVT, and can now also describe the so-called protein limit (polymer larger than the 'protein-like' colloids), where the binodal polymer concentrations scale in a simple way with the polymer/colloid size ratio. For an intermediate case (polymer size≈colloid size) we could give a quantitative description of careful experimental data. © 2010 Elsevier B.V. All rights reserved. Source

Buysman E.,Independent consultant to NBP | Mol A.P.J.,Wageningen University
Energy Policy | Year: 2013

In many of the least developed countries the energy security conundrum is how to provide affordable, safe and clean energy to a low income rural population. Household level generation of biogas from animal waste for both cooking and lighting, while producing high quality organic fertiliser, is increasingly proposed as a viable part of the solution for farming households. Since the early 1990s international development organisations - often in cooperation with the national government - have attempted to introduce biogas technologies in many least developed countries, but most initiatives failed. In this landscape of failed biogas development programmes the National Biodigester Programme (NBP) Cambodia started in 2006, with the aim to establish a permanent market oriented and self-financed biogas sector. The results show the development of a sustainable domestic biodigester sector, a rapid diffusion of biodigesters among poor rural households, but still ambivalences on financial independency from external funding and carbon finance. The conclusion is that a pure market model for biogas development in the rural area of the least developed countries will not easily work. Governmental regulation and coordination will remain needed, and carbon finance will not easily fully replace ODA and governmental financial support. © 2013 Elsevier Ltd. Source

Van Leeuwen H.P.,Wageningen University
Environmental Chemistry | Year: 2016

Soil humic acids and their metal complexes are sorbed by hydrogel phases such as those used in DGT analysis. The accumulation is spatially inhomogeneous: a thin film near the interface with the aqueous medium typically hosts ∼10 times the concentration in the medium, whereas the bulk gel features an accumulation factor of ∼2. Here we discuss the consequences of these sorption properties for the usual type of DGT experiment. It appears that the eventual steady-state metal flux is not affected, but the characteristic time of establishing truly steady-state diffusion conditions may be even longer than the common DGT deployment time of a few days. © 2016 CSIRO. Source

Oosterveer P.,Wageningen University
Journal of Cleaner Production | Year: 2014

Global demand for palm oil is increasing to fulfil worldwide needs for cooking oil, food ingredients, biofuels, soap and other chemicals. In response, palm oil production is rapidly expanding which promotes economic growth in producing countries but also leads to serious environmental and social problems such as destruction of tropical forests, climate change and threats to small-holder livelihoods. For these reasons, palm oil production and use have become highly controversial. However, the global character of palm oil production and consumption, the number of different actors involved and its multiple uses makes promotion its sustainability highly complex. Individual nation-states can no longer control and regulate a global flow like palm oil and alternative governing networks appear involving private companies and NGOs. Acknowledging the roles of such governance networks with different forms of power means that relying only on economic and political power to explain current dynamics in the palm oil sector is inadequate. In global networks like palm oil supply, encompassing transnational material flows and multiple actors, the relevance of each actor relates to his position in the network. Power in global palm oil supply is therefore not only related to their position in the (vertical) supply chains, but also to their role in the horizontal networks. New forms of power in networks arise from steering the networks (programming) and from connecting different networks (switching). In the multiple networks that compose global palm oil provision today, different programmers and switchers play critical roles. This is briefly illustrated in this paper on the basis of different cases of active steering in global palm oil provision. © 2014 Elsevier Ltd. All rights reserved. Source

Vellema S.,Wageningen University
Journal of Cleaner Production | Year: 2014

In the agri-food sector, global partnerships between lead firms and international NGOs design standards that aim to enhance environmental sustainability and to some extent realise social justice. However, the effectiveness of such standards is limited when their content and governance provokes resistance in production regions upstream in the chain. This paper addresses the question whether and how multi-stakeholder partnering makes internationally constructed standards fit local institutions, i.e. norms, rules and practices in producers' regions. The case studies make use of 'global value chain' and 'global production network' approaches to analyse two examples of global-local interactions: Utz Certified rooibos tea in South Africa and Aquaculture Stewardship Council certified shrimp in Indonesia. The analysis demonstrates that producer regions are not always merely standard-takers. Co-creation in standard-setting and certification may occur when the chain's commercial exploitation of natural resources threatens sourcing in the long term, when local partnerships experienced in environmental protection of the resource become involved in the implementation, and when global and local partnerships interact not only via hierarchically organised value chains, but also via a newly emerging public space. © 2014 Elsevier Ltd. All rights reserved. Source

Brouwer I.A.,VU University Amsterdam | Wanders A.J.,Wageningen University | Katan M.B.,VU University Amsterdam
European Journal of Clinical Nutrition | Year: 2013

This review asks the question if further research on trans fatty acids and cardiovascular health is needed. We therefore review the evidence from human studies on trans fatty acids and cardiovascular health, and provide a quantitative review of effects of trans fatty acid intake on lipoproteins. The results show that the effect of industrially produced trans fatty acids on heart health seen in observational studies is larger than predicted from changes in lipoprotein concentrations. There is debate on the effect of ruminant trans fatty acids and cardiovascular disease. Of special interest is conjugated linoleic acid (CLA), which is produced industrially for sale as supplements. Observational studies do not show higher risks of cardiovascular disease with higher intakes of ruminant trans fatty acids. However, CLA, industrial and ruminant trans fatty acids all raise plasma low-density lipoprotein and the total to high-density lipoprotein ratio. Gram for gram, all trans fatty acids have largely the same effect on blood lipoproteins. In conclusion, the detrimental effects of industrial trans fatty acids on heart health are beyond dispute. The exact size of effect will remain hard to determine. Further research is warranted on the effects of ruminant trans fatty acids and CLA on cardiovascular disease and its risk factors. © 2013 Macmillan Publishers Limited. Source

Koene P.,Wageningen University
Journal of Applied Animal Welfare Science | Year: 2013

This project aimed to estimate a species' adaptations in nature and in captivity, assess welfare, suggest environmental changes, and find species characteristics that underlie welfare problems in nonhuman animals in the zoo. First, the current status of zoo animal welfare assessment was reviewed, and the behavioral ecology approach was outlined. In this approach, databases of species characteristics were developed using (a) literature of natural behavior and (b) captive behavior. Species characteristics were grouped in 8 functional behavioral ecological fitness-related categories: space, time, metabolic, safety, reproductive, comfort, social, and information adaptations. Assessments of the strength of behavioral adaptations in relation to environmental demands were made based on the results available from the literature. The databases with literature at the species level were coupled with databases of (c) behavioral observations and (d) welfare assessments under captive conditions. Observation and welfare assessment methods were adapted from the animal on the farm realm and applied to zoo species. It was expected that the comparison of the repertoire of behaviors in natural and captive environments would highlight welfare problems, provide solutions to welfare problems by environmental changes, and identify species characteristics underlying zoo animal welfare problems. © 2013 Copyright Taylor and Francis Group, LLC. Source

van Oosten C.,Wageningen University
Journal of Sustainable Forestry | Year: 2013

Forest landscape restoration is gaining ground, not least because of the role of forests in mitigating climate change. At present, pilot projects are initiated to generate "good practice" and "lessons learned" that can be scaled up to higher levels of policy making. However, landscape restoration is not new. People have always been constructing and restoring their landscapes to safeguard their livelihoods. A better understanding of existing local practice will help in identifying and implementing new restoration initiatives, and assure sustainable outcomes. Understanding local restoration practice means: (a) understanding how the biophysical conditions of landscapes are reshaped over time through the collective decisions of a landscape's inhabitants; and (b) understanding the governance mechanisms underlying these collective decisions. Thinking of governance from a landscape perspective adds a spatial dimension to governance as a means of reconnecting governance to landscape, citizenship to place. This offers the opportunity to cross administrative and political boundaries, allowing for broader groups of actors to engage in spatial decision making. Constructing networks across scales thus becomes an instrument for enhancing learning processes within and between landscapes and a means to scale up good forest landscape restoration practice for wider application at a global scale. © 2013 Copyright Taylor and Francis Group, LLC. Source

Oonincx D.G.,Wageningen University
Zoo biology | Year: 2012

The aim of this study was to determine the chemical composition of eight invertebrate species and evaluate their suitability as alternative prey. The species selected were rusty red cockroaches (Blatta lateralis), six-spotted cockroaches (Eublaberus distanti), Madagascar hissing cockroaches (Gromphadorhina portentosa), fruit flies (Drosophila melanogaster), false katydids (Microcentrum rhombifolium), beetles of the mealworm (Tenebrio molitor), and superworm beetles (Zophobas morio), as well as woodlice (Porcellio scaber). Dry matter (DM), crude protein, crude fat, neutral detergent fiber, acid detergent fiber, ash, macro and trace minerals, vitamins A and E, and carotenoid concentrations were quantified. Significant differences were found between species. Crude protein content ranged from 38 to 76% DM, fat from14 to 54% DM, and ash from 2 to 8% DM. In most species, calcium:phosphorus was low (0.08-0.30:1); however, P. scaber was an exception (12:1) and might prove useful as a dietary source of calcium for insectivores. Vitamin E content was low for most species (6-16 mg/kg DM), except for D. melanogaster and M. rhombifolium (112 and 110 mg/kg DM). The retinol content, as a measure of vitamin A activity, was low in all specimens, but varied greatly among samples (0.670-886 mg/kg DM). The data presented can be used to alter diets to better suit the estimated requirements of insectivores in captivity. Future research on the topic of composition of invertebrate prey species should focus on determination of nutrient differences owing to species, developmental stage, and diet. © 2011 Wiley Periodicals, Inc. Source

van der Sman R.G.M.,Wageningen University
Food Hydrocolloids | Year: 2016

Ternary mixtures of biopolymers, sugars or polyols and water can be treated as a pseudo binary system with respect to melting of the biopolymer. Sugar and polyol solutions can be treated as an effective solvent, characterized by the density of hydroxyl groups available for intermolecular hydrogen bonding. Such a treatment has been shown earlier for the glass transitions of the ternary mixtures. Now we have analysed the melting behaviour of biopolymers in these ternary mixtures. If the melting points are plotted as function of the density of hydroxyl groups, all data for a variety of sugars and polyols collapse to a single curve. This master curve coincides with the prediction of the melting line for biopolymer/water mixtures as follows from Flory's theory. Such behaviour has been found for starch, gelatin, soy and sunflower proteins. © 2015 Elsevier Ltd. Source

van Loon-Steensma J.M.,Wageningen University
Mitigation and Adaptation Strategies for Global Change | Year: 2015

Concern about the effects of climate change have set in motion a search for flood protection measures to adapt coastlines to the foreseen accelerated sea level rise. In this context, the potential role of salt marshes to adapt the Wadden Sea’s flood defences was explored in the Netherlands Wadden Region Delta Programme. This paper provides an overview of the steps taken by the programme in developing a climate change adaptation strategy so that others might learn from its experiences. The second aim is to summarize the knowledge generated by the programme on the potential role of salt marshes as part of a climate change adaption strategy. Explorative modelling results indicate that Wadden Sea salt marshes affect wave heights, even under extreme conditions. Therefore, a salt-marsh zone in front of the Wadden Sea dikes that could keep pace with sea level rise may result in a reduced dike reinforcement task. A salt marsh potential map gives a rough impression of locations that are potentially interesting for salt marsh conservation and development, based on the current situation, on available information about abiotic conditions for salt marsh formation and the habitats present in the coastal zone. Besides elongated stretches were seminatural salt marshes are already present or developing, several stretches along the Dutch Wadden Sea coast have favourable abiotic conditions for salt marsh development. However, the prospects for integrating salt marshes into flood defences depend also on other aspects. Various nature conservation agreements are in effect with their associated obligations. Furthermore, the foreseen value of salt marsh development compared to traditional reinforcements, in terms of both costs and benefits, must be considered. © 2015, The Author(s). Source

Genetic selection is a major force shaping life on earth. In classical genetic theory, response to selection is the product of the strength of selection and the additive genetic variance in a trait. The additive genetic variance reflects a population's intrinsic potential to respond to selection. The ordinary additive genetic variance, however, ignores the social organization of life. With social interactions among individuals, individual trait values may depend on genes in others, a phenomenon known as indirect genetic effects. Models accounting for indirect genetic effects, however, lack a general definition of heritable variation. Here I propose a general definition of the heritable variation that determines the potential of a population to respond to selection. This generalizes the concept of heritable variance to any inheritance model and level of organization. The result shows that heritable variance determining potential response to selection is the variance among individuals in the heritable quantity that determines the population mean trait value, rather than the usual additive genetic component of phenotypic variance. It follows, therefore, that heritable variance may exceed phenotypic variance among individuals, which is impossible in classical theory. This work also provides a measure of the utilization of heritable variation for response to selection and integrates two well-known models of maternal genetic effects. The result shows that relatedness between the focal individual and the individuals affecting its fitness is a key determinant of the utilization of heritable variance for response to selection. Source

Van Der Sman R.G.M.,Wageningen University
Journal of Physical Chemistry B | Year: 2013

We show that the glass transition of a multitude of mixtures containing hydrogen bonding materials correlates strongly with the effective number of hydroxyl groups per molecule, which are available for intermolecular hydrogen bonding. This correlation is in compliance with the topological constraint theory, wherein the intermolecular hydrogen bonds constrain the mobility of the hydrogen bonded network. The finding that the glass transition relates to hydrogen bonding rather than free volume agrees with our recent finding that there is little difference in free volume among carbohydrates and polysaccharides. For binary and ternary mixtures of sugars, polyols, or biopolymers with water, our correlation states that the glass transition temperature is linear with the inverse of the number of effective hydroxyl groups per molecule. Only for dry biopolymer/sugar or sugar/polyol mixtures do we find deviations due to nonideal mixing, imposed by microheterogeneity. © 2013 American Chemical Society. Source

Teuling A.J.,Wageningen University
Hydrology and Earth System Sciences | Year: 2011

Climate is often defined in terms of discrete classes. Here I use bivariate colour mapping to show that the global distribution of Köppen-Geiger climate classes can largely be reproduced by combining the simple means of two key states of the climate system (i.e. air temperature and relative humidity). This allows for a classification that is not only continuous in space, but can be applied at and transferred between timescales ranging from days to decades. © 2011 Author(s). Source

Van Leeuwen H.P.,Wageningen University
Environmental Chemistry | Year: 2011

Environmental contextDiffusive gel layer techniques can measure fluxes of chemical species in aqueous environmental media. Nanoparticulate metal complexes are small enough to penetrate gels, but their diffusive response is much slower than that of the free metal ions. Hence, time-resolved analysis of the diffusive flux of the complex sample is proposed as a chemical speciation tool for the nanodomain. AbstractFor a fully labile complex system, the diffusive gradients in thin film (DGT) metal flux approaches the fairly simple limit defined by the joint diffusion of the free metal ion and the complex species in the gel layer. Natural soft nanoparticulate complexes, such as those with humics and fulvics, generally enter the DGT gel phase and some of them may even be adsorbed by the gel matrix. The time characteristics of the DGT response are affected by a lower rate of diffusion, as well as by possible accumulation of nanoparticulate species in the gel layer. Several cases are discussed in some detail on the basis of numerical analysis of the diffusion process. If the difference between the diffusion coefficients of the free metal ion and the nanoparticulate complex is sufficiently large, the time-resolved DGT flux allows for distinction between these two types of species. © 2011 CSIRO. Source

Bartels J.,VU University Amsterdam | Onwezen M.C.,Wageningen University
International Journal of Consumer Studies | Year: 2014

This study investigates how social representations and consumers' identification with organic food consumers affects intentions to buy products that make environmental and ethical claims. For the purposes of the study, an online panel study was conducted on a representative sample of consumers (n=1006) in the United Kingdom. The results demonstrate that consumers who are adherent to natural foods or technology and do not perceive food as a necessity are more willing to buy environmentally friendly and ethical products. There seems to be no relationship between perceptions of food as a source of enjoyment and intentions to buy sustainable products. Finally, social identification with the organic consumer is positively related with the intentions to buy products that make environmental and ethical claims. The current research demonstrates that both individual perceptions of food and consumers' perceptions of the social environment play an important role in promoting environmentally friendly and ethical behaviour. © 2013 John Wiley & Sons Ltd. Source

De Graaf C.,Wageningen University
Proceedings of the Nutrition Society | Year: 2011

Liquids have been shown to have a low satiating efficiency. The may be related to the high rate of consumption for liquids which may be higher than 200 g/min. In a number of studies, we showed that the positive relationship between eating rate and energy intake is mediated by oro-sensory exposure time. Longer sensory exposure times are consistently associated with lower food intakes. This observation maybe linked to the role of cephalic phase responses to foods. Cephalic phase responses are a set of physiological responses, which are conceived to prepare the digestive system for the incoming flow of nutrients after ingestion, with the aim of maintaining homeostasis. Results from various studies suggest that cephalic phase responses are much smaller (absent) for liquids compared to solids. It is hypothesised that the absence of cephalic phase responses to liquid foods may be one of the causes why liquid energies enter the body undetected and lead to weak energy intake compensation. This idea fits with the concept of the taste system as a nutrient-sensing system that informs the brain and the gastro-intestinal system about what is coming into our body. With liquids, this system is bypassed. Slower eating may help the human body to associate the sensory signals from food with their metabolic consequences. Foods that are eaten quickly may impair this association, and may therefore lead to overconsumption of energy, and ultimately to weight gain. © The Author 2011. Source

Vrieling A.,German Cancer Research Center | Kampman E.,Wageningen University
American Journal of Clinical Nutrition | Year: 2010

The role of dietary and other lifestyle factors in colorectal cancer recurrence and survival is largely unknown. We conducted a review to summarize the evidence from epidemiologic studies that examined the association of body mass index (BMI), physical activity, and nutrition with colorectal cancer recurrence and survival. We searched MEDLINE and EMBASE for relevant epidemiologic studies published up to March 2010 by using MeSH terms and related key words. We identified 36 articles that were based on 31 independent studies on BMI (n = 21), physical activity (n = 6), or nutrition (n = 12) in relation to colorectal cancer recurrence and survival. Studies were generally based on follow-up of cases in existing patient series, case-control or cohort studies, or chemotherapy trials. BMI, physical activity, and nutrition mostly referred to the time at or before diagnosis. Only 10 studies assessed BMI (n = 1), physical activity (n = 4), or nutrition (n = 5) after diagnosis. There may be an association between higher BMI and body fatness before or at the time of diagnosis and a higher all-cause mortality or colorectal cancer-specific mortality or recurrence, although results may differ by sex, tumor location, and molecular subtype. There may be a relation between higher leisure-time physical activity after diagnosis and a lower all-cause or colorectal cancer-specific mortality. For dietary factors, statistically significant associations were only shown for single foods, nutrients, and dietary patterns in single studies. In conclusion, only a paucity of data is available on the effect of dietary and other lifestyle factors on colorectal cancer recurrence and survival. Thus far, no clear conclusions can be drawn. Future studies are warranted, particularly on postdiagnosis BMI and diet. © 2010 American Society for Nutrition. Source

Gardebroek C.,Wageningen University | Hernandez M.A.,International Food Policy Research Institute
Energy Economics | Year: 2013

This paper examines volatility transmission in oil, ethanol and corn prices in the United States between 1997 and 2011. We follow a multivariate GARCH approach to evaluate the level of interdependence and the dynamics of volatility across these markets. The estimation results indicate a higher interaction between ethanol and corn markets in recent years, particularly after 2006 when ethanol became the sole alternative oxygenate for gasoline. We only observe, however, significant volatility spillovers from corn to ethanol prices but not the converse. We also do not find major cross-volatility effects from oil to corn markets. The results do not provide evidence of volatility in energy markets stimulating price volatility in the US corn market. © 2013 Elsevier B.V. Source

Bintanja R.,Royal Netherlands Meteorological Institute | Graversen R.G.,Royal Netherlands Meteorological Institute | Graversen R.G.,University of Stockholm | Hazeleger W.,Royal Netherlands Meteorological Institute | Hazeleger W.,Wageningen University
Nature Geoscience | Year: 2011

Pronounced warming in the Arctic region, coined Arctic amplification, is an important feature of observed and modelled climate change1,2. Arctic amplification is generally attributed to the retreat of sea-ice3 and snow, and the associated surface-albedo feedback4, in conjunction with other processes5-8. In addition, the predominant thermal surface inversion in winter has been suggested to pose a negative feedback to Arctic warming by enhancing infrared radiative cooling9. Here we use the coupled climate model EC-Earth10 in idealized climate change experiments to quantify the individual contributions of the surface and the atmosphere to infrared radiative cooling. We find that the surface inversion in fact intensifies Arctic amplification, because the ability of the Arctic wintertime clear-sky atmosphere to cool to space decreases with inversion strength. Specifically, we find that the cold layers close to the surface in Arctic winter, where most of the warming takes place, hardly contribute to the infrared radiation that goes out to space. Instead, the additional radiation that is generated by the warming of these layers is directed downwards, and thus amplifies the warming. We conclude that the predominant Arctic wintertime temperature inversion damps infrared cooling of the system, and thus constitutes a positive warming feedback. © 2011 Macmillan Publishers Limited. All rights reserved. Source

Stellwagen D.R.,University Utrecht | Bitter J.H.,University Utrecht | Bitter J.H.,Wageningen University
Green Chemistry | Year: 2015

This work demonstrates for the first time that carbide particle size is a critical factor for the activity and stability of carbon supported tungsten- and molybdenum carbide catalysts in (hydro-)deoxygenation reactions. The stability of the catalyst was shown to increase for larger particles due to the improved resistance of the metal carbide phase against full oxidation to crystalline metal oxides under reaction conditions. In addition to the improved catalyst stability, supported molybdenum carbides were found to more than double their weight-based catalytic activity upon increasing carbide particle size from 2 to 10 nanometers. The strongly improved (de-)hydrogenation activity of these larger carbide particles also facilitated a new deoxygenation pathway for fatty acids, in which an initial hydrogenation to fatty-aldehyde is combined with a decarbonylation step. This is the first time in which this deoxygenation pathway is observed over supported tungsten- or molybdenum carbide catalysts. © The Royal Society of Chemistry 2015. Source

Mol A.P.J.,Wageningen University
Environmental Politics | Year: 2016

The environmental nation state is not a formal category but a substantive one. The current set of national environmental state institutions originated in the late 1960s/1970s but has since changed in character. Many scholars note that since the new millennium, the environmental nation state in OECD countries is losing power and authority and is thus in decline, in line with wider concerns about the positions of states versus markets under conditions of (neo-liberal) globalisation. Assessing the decline of environmental nation state authority, three conclusions are drawn. States do not lose power in all sectors vis-à-vis markets. Hence, environmental nation state decline does not follow a general tendency. Second, the decline of environmental nation state powers cannot be equated with less effective or lower levels of environmental protection, as other environmental authorities have stepped in, and the jury is still out on their environmental effectiveness. Third, declining powers of environmental nation state institutions increasingly become a self-fulfilling prophecy of environmental policymakers, but non-state environmental authorities cannot take over all environmental state functions. © 2015 Taylor & Francis. Source

Klomp J.,Wageningen University
Global Environmental Change | Year: 2016

In this study we examine the impact of large-scale natural disasters on economic development. A major obstacle in exploring this relationship is the poor data quality on GDP per capita in low-income countries, while at the same time more than 90% of all disasters that happen worldwide occur in these particular countries. To overcome this problem, we use data based on satellite images of the night-time light intensity in a specific country or region which is shown to be highly correlated with income per capita. After testing for the sensitivity of the results, our main findings suggest that natural disasters reduce the amount of lights visible from outer space significantly in the short run. To be more precise, we demonstrate that climatic and hydrological disasters cause a large drop in the luminosity in developing and emerging market countries, while geophysical and meteorological disasters decrease light intensity more in industrialized countries. It turns out that using reported real GDP per capita figures underestimates the true impact. Besides, a large part of the economic consequences of the natural events is explained by their regional impact. However, in the long run most of the disaster effect has disappeared. Finally, the impact of a disaster depends partly on the size and scope of the natural catastrophe, the geographical location, the degree of financial development of a country and the quality of the political institutions present. © 2015 Elsevier Ltd. Source

van Tatenhove J.P.M.,Wageningen University
Environmental Politics | Year: 2016

Seas and oceans are confronted with a plethora of environmental problems, caused by land-based activities (agriculture, industries, and ports) and by maritime activities (such as shipping, fishing, oil and gas drilling, tourism, and navigational dredging). Environmental problems at sea challenge the efficacy of state sovereignty. Who is responsible, accountable, and regulates environmental and spatial problems at the level of regional seas, and what is the role of states in these processes of governance? In the regional seas and on the high seas, the environmental state is challenged by two developments: states become players at different levels, and states are confronted with the activities of big market players where they have no or little jurisdiction. The different forms of the environmental state in Europe’s regional seas and in the Arctic Ocean are examined. © 2015 Taylor & Francis. Source

The separation of Thecacoris and Cyathogyne (Phyllanthaceae, formerly Euphorbiaceae) is discussed and it is concluded that they should remain united. A separation of the continental forest species (except Thecacoris viridis (Müll.Arg.) Leandri ex G.L.Webster) awaits molecular investigation. Thecacoris micrantha sp. nov. is described and illustrated. Thecacoris grandifolia (Pax & K.Hoffm.) Govaerts from Cameroon is neotypified. Thecacoris membranacea Pax and T. annobonae Pax & K.Hoffm. are lectotypified and placed in synonymy under T. stenopetala (Müll.Arg.) Müll.Arg. and T. trichogyne Müll.Arg., respectively. Thecacoris manniana (Müll.Arg.) Müll.Arg. is united with T. stenopetala under the latter name. A key to and a synopsis of the West African species is provided. © 2011 Trustees of the Royal Botanic Garden Edinburgh. Source

Harvey J.A.,Netherlands Institute of Ecology | Gols R.,Wageningen University
Population Ecology | Year: 2011

The warty cabbage Bunias orientalis is an invasive pest in much of central Europe, including much of Germany since the 1980s, whereas in other countries, such as The Netherlands, it is a less common exotic species. Here, healthy larvae of Mamestra brassicae, which has been found feeding on B. orientalis plants in Germany, and larvae parasitized by one of its major larval endoparasitoids Microplitis mediator, were reared on both herbivore-induced and noninduced leaves of B. orientalis originating from single large populations growing in The Netherlands and central Germany. Herbivore performance was less negatively affected than parasitoid performance by differences in plant quality. Development times in both M. brassicae and Mi. mediator were shorter on Dutch than German plants and also shorter on noninduced than induced plants. Moreover, survival and body size of the parasitoid was more strongly affected by plant population and induction than survival of healthy M. brassicae. Chemical analyses of defensive secondary metabolites [glucosinolates (GS)] revealed that concentrations of the major GS sinalbin were constitutively expressed in German plants whereas they were induced in Dutch plants. However, in separate feeding bioassays in which preference for induced and noninduced leaves was compared separately, L3 instars of M. brassicae preferred noninduced German plants over Dutch plants but induced Dutch plants over German plants, revealing that changes in primary metabolites or an unidentified non-GS compound mediates population-related differences in plant quality. The results reveal asymmetric effects of plant quality in exotic plants on organisms in the second and third trophic level. © 2011 The Author(s). Source

van der Sman R.G.M.,Wageningen University
Meat Science | Year: 2013

In this paper we present a numerical model describing the heat and mass transport during the cooking of chicken meat in industrial tunnels. The mass transport is driven by gradients in the swelling pressure, which is described by the Flory-Rehner theory, which relates to the water holding capacity (WHC). For cooking temperatures up to boiling point and practical relevant cooking times, the model renders good prediction of heat and mass transport and the total loss of moisture. We have shown that for cooking temperatures above boiling point, the model has to be extended with the dynamic growth of capillary water (drip) channels. Furthermore, we discuss that the Flory-Rehner theory provides the proper physical basis for describing the change of the WHC by a wide variety of factors like salt and pH. © 2013 Elsevier Ltd. Source

Van Der Most P.J.,University of Groningen | De Jong B.,University of Groningen | Parmentier H.K.,Wageningen University | Verhulst S.,University of Groningen
Functional Ecology | Year: 2011

1.Evidence suggests that developing and maintaining an effective immune system may be costly and that an organism has to make a trade-off between immune function and other fitness-enhancing traits. To test for a trade-off between growth and immune function we carried out a meta-analysis of data from lines of poultry that had been divergently selected for either growth (body mass) or an aspect of immune function. This is relevant to our understanding of the evolution of immune function, but also because the increased prevalence of antibiotic-resistant bacteria and calls to restrict the use of antibiotics in the agricultural industry has made immune function of livestock an important theme. Has the selection of animals for rapid growth unintentionally resulted in reduced immune function? 2.The lines selected for increased growth all showed a strong and significant decrease in immune function (standard difference in means = 0·8; P < 0·001). No difference was found between the effects on cellular or humoral immunity, although there were few data on cellular immunity, and hence this deserves more study. However, in the lines selected for immune function the effect on growth was heterogeneous and overall it was close to zero. 3.Testing for publication bias revealed that the effect of selection for body mass on immune function was robust. However, there was considerable heterogeneity in both body mass and immune function data. The heterogeneity in the growth-selected lines cannot be accounted for by gender or species: the only turkey line had an effect size between that of the two chicken lines. 4.In conclusion, we found that selection for growth does indeed compromise immune function, but selection for immune function did not consistently affect growth. This is in agreement with the supposition that the costs of growth are large relative to the costs of immune function, and on a practical level this suggests that it may be possible to breed animals for increased growth without loss of immune function. © 2010 The Authors. Functional Ecology © 2010 British Ecological Society. Source

Leeuwis C.,Wageningen University | Aarts N.,University of Amsterdam
Journal of Agricultural Education and Extension | Year: 2011

This paper systematically rethinks the role of communication in innovation processes, starting from largely separate theoretical developments in communication science and innovation studies. Literature review forms the basis of the arguments presented. The paper concludes that innovation is a collective process that involves the contextual re-ordering of relations in multiple social networks. Such re-ordering cannot be usefully understood in terms of 'diffusing' ready-made innovations. Hence, we need to think about communication as playing a role in innovation development and 'design'. In such development processes, everyday communicative exchanges and self-organisation among societal agents are likely to be of critical significance in connection with the re-ordering of social relationships. In this light, the role of communication professionals and deliberate communication is often overstated or misinterpreted. Instead of striving for predefined change, communication professionals should facilitate that 'the potential for change' in complex dynamical settings increases. This includes efforts to enhance the survival chances of existing initiatives for change, by facilitating that they become more effectively adapted and/or linked to their dynamic selection environment than competing initiatives. This implies that communication professionals must play broader intermediary roles than before. A systematic rethinking of the role of communication in innovation processes in view of recent developments in communication sciences, innovation studies and complex systems thinking is largely absent. This paper fills a void © 2011 Wageningen University. Source

Two NPK factorial trials, one in Vietnam and one in The Netherlands were (re-)analyzed to find causes of success or failure with regard to sustained soil productivity, using the concept of crop nutrient equivalents (CNE). A (k)CNE is the quantity of a nutrient that, under conditions of balanced nutrition, has the same effect on yield as 1 (k)g of nitrogen. The percentages the nutrients take in the (k)CNE sum of N, P and K are plotted along the sides of a triangle. Soil, crop and input NPK are indicated in the triangle. Balanced crop NPK is found in the centre of the triangle, and required NPK inputs are on a straight line in the extension of the line trough the point of soil NPK and the centre. Experimental inputs were compared with inputs required for balanced NPK. In Vietnam, responses to P and soil available N:P:K pointed to severe shortage of P. Rice yields increased over time in dry but not in wet seasons. The lower yields in wet seasons were ascribed to insufficiently long periods between the dry and the next wet seasons for replenishment of labile soil P. In the Netherlands, four crops were grown in rotation on a former sea bottom. Only N had a strong effect on yield. Soil available N:P:K revealed low N, very high K and medium P. Recovery of fertilizer N was high because of capillary rise of groundwater and absence of leaching. In both trials, first-season chemical crop analysis would directly have detected disproportions of soil available N, P and K. This knowledge could have improved the experimental designs, optimized nutrient use efficiency and minimized losses of N and K to the environment. © 2010 The Author(s). Source

Glover D.,Wageningen University
NJAS - Wageningen Journal of Life Sciences | Year: 2011

The System of Rice Intensification (SRI) is claimed to be a new, more productive and more sustainable method for cultivating rice. These claims have proved controversial. One dimension of the controversy has centred on the imprecision with which SRI's component practices have been defined. The supporters of SRI suggest that the system has been designed to satisfy the needs of rice itself, implying that it is a set of integrated, mutually reinforcing practices that need to be implemented as a package in order to obtain the best results. However, they also argue that the system should be understood as a suite of flexible principles to be adapted to particular agro-ecological and socio-economic settings - the antithesis of a fixed package. This poses a conceptual and practical challenge for scientific evaluation of SRI methods. However, this apparent difficulty is chiefly an artefact created by conceptualizing agricultural methods as standardized packages. A process of translation is always necessary to convert theoretical models or norms into farming practices. Smallholder farming practices, being intrinsically constrained and contingent, rarely conform precisely to abstract norms. As an alternative, the notion of performance offers a useful way to frame a methodological and analytical approach to understanding what is going on in SRI. Such an approach calls for close technographic observation of farming activities and the interaction between farmers and their fields, plants and tools. © 2010 Royal Netherlands Society for Agricultural Sciences. Source

Almekinders C.J.M.,Wageningen University
NJAS - Wageningen Journal of Life Sciences | Year: 2011

Participatory Plant Breeding (PPB) is one of the areas of Participatory Technology Development (PTD) in which collaboration of researchers and farmers has been reported as quite successful although its institutionalization remains problematic. This paper aims to contribute to better understanding of PPB processes. It focuses on the practices of developing a common bean variety (Phaseolus vulgaris L.) by a group consisting of a breeder, farmers and NGO technician in northern Nicaragua. The description is an example of a technography and uses the concept of boundary object to analyse how actors come together around a shared goal and how their knowledge and practices are combined in the material making of five varieties, eventually leading to JM-12.7 as a formally released variety. The material making of five bean varieties is central in the first part of the process and shows how in practice different knowledges within the group interact. The second part of the process leads to distinguishing socio-political boundaries. The formal registration of JM-12.7 required crossing of these boundaries and prompted the reorganization of the group into a co-operative. © 2011 Published by Elsevier B.V. on behalf of Royal Netherlands Society for Agricultural Sciences. Source

Calus M.P.L.,Wageningen University
Animal | Year: 2010

Animal breeding faces one of the most significant changes of the past decades the implementation of genomic selection. Genomic selection uses dense marker maps to predict the breeding value of animals with reported accuracies that are up to 0.31 higher than those of pedigree indexes, without the need to phenotype the animals themselves, or close relatives thereof. The basic principle is that because of the high marker density, each quantitative trait loci (QTL) is in linkage disequilibrium (LD) with at least one nearby marker. The process involves putting a reference population together of animals with known phenotypes and genotypes to estimate the marker effects. Marker effects have been estimated with several different methods that generally aim at reducing the dimensions of the marker data. Nearly all reported models only included additive effects. Once the marker effects are estimated, breeding values of young selection candidates can be predicted with reported accuracies up to 0.85. Although results from simulation studies suggest that different models may yield more accurate genomic estimated breeding values (GEBVs) for different traits, depending on the underlying QTL distribution of the trait, there is so far only little evidence from studies based on real data to support this. The accuracy of genomic predictions strongly depends on characteristics of the reference populations, such as number of animals, number of markers, and the heritability of the recorded phenotype. Another important factor is the relationship between animals in the reference population and the evaluated animals. The breakup of LD between markers and QTL across generations advocates frequent re-estimation of marker effects to maintain the accuracy of GEBVs at an acceptable level. Therefore, at low frequencies of re-estimating marker effects, it becomes more important that the model that estimates the marker effects capitalizes on LD information that is persistent across generations. © 2009 The Animal Consortium. Source

Lenzholzer S.,Wageningen University
International Journal of Biometeorology | Year: 2010

Acceptance of public spaces is often guided by perceptual schemata. Such schemata also seem to play a role in thermal comfort and microclimate experience. For climate-responsive design with a focus on thermal comfort it is important to acquire knowledge about these schemata. For this purpose, perceived and "real" microclimate situations were compared for three Dutch urban squares. People were asked about their long-term microclimate perceptions, which resulted in "cognitive microclimate maps". These were compared with mapped microclimate data from measurements representing the common microclimate when people stay outdoors. The comparison revealed some unexpected low matches; people clearly overestimated the influence of the wind. Therefore, a second assumption was developed: that it is the more salient wind situations that become engrained in people's memory. A comparison using measurement data from windy days shows better matches. This suggests that these more salient situations play a role in the microclimate schemata that people develop about urban places. The consequences from this study for urban design are twofold. Firstly, urban design should address not only the "real" problems, but, more prominently, the "perceived" problems. Secondly, microclimate simulations addressing thermal comfort issues in urban spaces should focus on these perceived, salient situations. © 2009 The Author(s). Source

Richards P.,Wageningen University
Disasters | Year: 2010

Those who intervene in crises must take care to ensure that assistance does not undermine the processes through which social cohesion is generated or restored. From a neo-Durkheimian analytical perspective, feeding creates social loyalties as well as saves lives. Humanitarian agencies provide practical assistance to livelihoods, but they need also to create space for the ritual agency on which social cohesion depends. Attention to the rituals of food distribution helps humanitarian actors to address a potentially damaging dissociation between social and material facts. A post-war food security project in Sierra Leone is used to illustrate the point. The lessons of this intervention have implications for the organisation of humanitarian assistance at all levels, both international and local. The paper argues that establishing space for ritualisation within humanitarian programmes is an obligation for those who wish to do no harm. © 2010 The Author(s). Journal compilation © Overseas Development Institute, 2010. Source

Diamant M.,VU University Amsterdam | Blaak E.E.,Maastricht University | de Vos W.M.,Wageningen University | de Vos W.M.,University of Helsinki
Obesity Reviews | Year: 2011

The current obesity and type 2 diabetes pandemics have causes beyond changes in eating and exercise habits against a susceptible genetic background. Gut bacteria seem to additionally contribute to the differences in body weight, fat distribution, insulin sensitivity and glucose- and lipid-metabolism. Data, mostly derived from preclinical studies, suggest that gut microbiota play an important role in conditions such as obesity, diabetes, metabolic syndrome and non-alcoholic fatty liver disease. Regulation of energy uptake from the gut, by digesting otherwise indigestible common polysaccharides in our diet, production or activation of signalling molecules involved in host metabolism, modification of gut permeability, the release of gut hormones and inflammation, are among the mechanisms by which gut microbiota may influence the host cardiometabolic phenotype. Recent evidence suggests that quantitative and qualitative differences in gut microbiota exist between lean and obese, and between diabetic and non-diabetic individuals. Modification of the gut microbiota composition and/or its biochemical capacity by specific dietary or pharmacological interventions may favourably affect host metabolism. Large-scale intervention trials, investigating the potential benefit of prebiotics and probiotics in improving cardiometabolic health in high-risk populations, are eagerly awaited. © 2010 The Authors. obesity reviews © 2010 International Association for the Study of Obesity. Source

van Arendonk J.A.M.,Wageningen University
Livestock Science | Year: 2011

The world is faced with the challenge to meet the increasing demand for livestock products while conserving animal genetic resource diversity and maintaining environmental integrity. Genetic improvement of local breeds can help to improve the livelihood of the livestock keepers, to increase the production of animal products and to conserve genetic diversity. Implementing breeding schemes in developing countries has proven to be very difficult. The objective of this paper is to discuss the role of reproductive technologies for the creation and dissemination of genetic improvement in livestock populations in developing countries. In the paper opportunities are discussed for implementing breeding schemes which minimize the need for extensive pedigree and performance recording. It is shown that genetic progress can be generated in a small population. Community-based breeding schemes offer a good starting point for involving farmers in improving local breeds. Artificial insemination to exchange genetic material between communities offers an opportunity to increase the rate of genetic improvement while restricting the rate of inbreeding. Furthermore, artificial insemination is a promising technique for dissemination of genetic gain to producers at a relatively low cost. Opportunities to use semen sexing in a crossbreeding scheme are presented. It is concluded that tailor-made solutions and long-term commitment are needed in order to meet the needs of farmers to increase their livelihoods and to meet the needs of the growing population of consumers. © 2010 Elsevier B.V. Source

Trienekens J.H.,Wageningen University
International Food and Agribusiness Management Review | Year: 2011

The paper presents a framework for developing country value chain analysis made up of three components. The first consists of identifying major constraints for value chain upgrading: market access restrictions, weak infrastructures, lacking resources and institutional voids. In the second component three elements of a value chain are defined: value addition, horizontal and vertical chain-network structure and value chain governance mechanisms. Finally, upgrading options are defined in the area of value addition, including the search for markets, the value chain- network structure and the governance form of the chain. Part of this component is the identification of the most suitable partnerships for upgrading the value chain. The three components of the framework are derived from major theoretical streams on inter-company relationships and from the literature on developing country value chains. The framework is applied in a case example of a developing country value chain. © 2011 International Food and Agribusiness Management Association (IFAMA). Source

Royer A.,Wageningen University
Agricultural Economics | Year: 2011

This study measures the magnitude of transaction costs incurred by milk producers in their contractual relations with dairy processors in two different coordination mechanisms: centralized contracting through a marketing board and decentralized bilateral contracting. Interviews and surveys were conducted to estimate transaction costs faced by producers marketing through the Québec milk marketing board in Canada and bilateral contracts in England and Wales in the United Kingdom using the measurement methodology of the cost of exchange. Our results show that the relative magnitude of transaction costs incurred by producers across both settings is quite low, which indicates that both hybrid coordination mechanisms minimize transaction costs in the dairy sector. However, results from the bilateral contracting setting indicate a strong heterogeneity of transaction costs levels among farmers. In that respect, the milk marketing board and its institutional setting would act as a collective insurance, pooling transaction costs and sharing them among producers. Our analysis leads to recommendations on bilateral contracting. © 2010 International Association of Agricultural Economists. Source

Maat H.,Wageningen University
NJAS - Wageningen Journal of Life Sciences | Year: 2011

An agricultural experiment is usually associated with a scientific method for testing certain agricultural phenomena. A central point in the work of Paul Richards is that experimentation is at the heart of agricultural practice. The reason why agricultural experiments are something different for farmers and agronomists is not their capacity to experiment as such but the embedding of experiments in a specific ecological, material and institutional environment. Using a historical perspective, changes are examined in the organization of agricultural experiments focusing on the Netherlands and colonial Indonesia during the first half of the 20th century and the international agricultural research institutes for the period thereafter. The results show a gradual shift in the role of experiments in the connection between science and practice. Initially, the link was considered to be established through various forms of experiments, rooted in an integrated social and technical understanding of agronomy. Gradually, this turned into a connection primarily established through various forms of communication. Recent work of Richards incorporates ideas that address key issues emerging from the history of agricultural experiments, dealing with an integrated social and technical understanding of agriculture. © 2010 Royal Netherlands Society for Agricultural Sciences. Source

Klerkx L.,Wageningen University | Nettle R.,University of Melbourne
Food Policy | Year: 2013

Policymakers and innovation scholars share an increasing interest in how to operationalize innovation support given the increasing number and range of stakeholders engaged in co-producing innovation. Using comparative case study analysis, this article examines support initiatives for dairy sector innovation in The Netherlands and Australia, addressing common challenges such as environmental issues, cattle health, new technology, and human resources. To this end, a review was conducted of documented information and articles published on the initiatives. The qualitative analysis focused on how the co-production process was supported and the achievements and challenges associated with each case. Across both countries and between different initiatives, the main achievements were found to be the generation of very different ideas addressing dairy sector challenges and attempting to bridge public and private sector interests. The main challenges included maintaining effort and momentum for high ambition targets and the potential for duplication as stakeholders became enrolled in different initiatives sponsored by different organizations in an increasingly devolved institutional setting. Furthermore, without strong institutional support for innovation co-production processes, individual actors were less able to operate effectively in innovation co-production roles. It is concluded that dairy sector innovation policies should address institutional constraints (e.g. provision of leadership and rewards for involvement in co-production processes), recognize that facilitation of innovation co-production needs to be adequately resourced, enhance support for initiative coordination to avoid duplication of effort, and take into account the specific institutional setting of countries and sectors to guide the design of innovation co-production support initiatives. © 2013 Elsevier Ltd. Source

Kardol P.,Swedish University of Agricultural Sciences | De Deyn G.B.,Wageningen University | Laliberte E.,University of Western Australia | Mariotte P.,Swiss Federal Institute of forest | Hawkes C.V.,University of Texas at Austin
Journal of Ecology | Year: 2013

Plant effects on soil biota can result in feedbacks affecting plant performance, with consequences for plant community and ecosystem dynamics on short and long time-scales. In addition, the strength and direction of plant-soil feedbacks depend on temporal shifts in abiotic environmental conditions. We synthesize current knowledge on temporal aspects of plant-soil feedbacks and present new ideas to better understand and predict the effects of plant-soil feedbacks on community and ecosystem properties across temporal scales. Explaining short-term temporal feedback dynamics requires us to better understand mechanistic linkages between plants, soil organisms and locally available resources. On the other hand, we need to refine our understanding of the context-dependency of plant-soil feedbacks, as the strength and direction of feedback interactions are influenced by 'external' temporal ecosystem dynamics, such as variation in soil resource availability after disturbance or during succession. Synthesis. Based on our synthesis of temporal aspects of plant-soil feedbacks, we suggest three main avenues for future research: (i) how plant-soil feedbacks changes with ontogeny, (ii) how plant and soil organism traits drive temporal variation in plant-soil feedbacks and (iii) how environmental changes across temporal scales alter the strength and direction of plant-soil feedbacks. © 2013 The Authors. Journal of Ecology © 2013 British Ecological Society. Source

van't Riet J.,Wageningen University | Ruiter R.A.C.,Maastricht University
Health Psychology Review | Year: 2013

It is a common finding that recipients of threatening health-promoting information are motivated to dismiss or disregard the information, thus reacting 'defensively'. This article gives an overview of the literature on defensive reactions to health-promoting information. A distinction is made between: (1) avoidance, (2) denial, (3) cognitive reappraisal and (4) suppression. Although these defensive reactions have been studied repeatedly and thoroughly, we propose that a number of questions remain unanswered. First, little is known about whether avoidance, denial, cognitive reappraisal and suppression have distinct or similar effects on emotional experience and health-conducive behaviour. Second, little is known about the development of defensive reactions over time in case recipients are repeatedly exposed to health-promoting information, which is often the case in a real-life setting. In the present article, we present preliminary answers to these questions, suggesting that cognitive reappraisal has greater potential to result in effective emotion regulation and is more likely to impede healthy behaviour than the other three strategies. We also propose that defensive reactions to health-promoting information do not always reduce health-conducive responses but can co-occur with more adaptive responses or even facilitate them. Finally, we present a hypothesised model of the development of defensiveness over time. © 2013 Copyright Taylor and Francis Group, LLC. Source

Brouwer I.A.,VU University Amsterdam | Wanders A.J.,VU University Amsterdam | Wanders A.J.,Wageningen University | Katan M.B.,VU University Amsterdam
PLoS ONE | Year: 2010

Background: Trans fatty acids are produced either by industrial hydrogenation or by biohydrogenation in the rumens of cows and sheep. Industrial trans fatty acids lower HDL cholesterol, raise LDL cholesterol, and increase the risk of coronary heart disease. The effects of conjugated linoleic acid and trans fatty acids from ruminant animals are less clear. We reviewed the literature, estimated the effects trans fatty acids from ruminant sources and of conjugated trans linoleic acid (CLA) on blood lipoproteins, and compared these with industrial trans fatty acids. Methodology/Principal Findings: We searched Medline and scanned reference lists for intervention trials that reported effects of industrial trans fatty acids, ruminant trans fatty acids or conjugated linoleic acid on LDL and HDL cholesterol in humans. The 39 studies that met our criteria provided results of 29 treatments with industrial trans fatty acids, 6 with ruminant trans fatty acids and 17 with CLA. Control treatments differed between studies; to enable comparison between studies we recalculated for each study what the effect of trans fatty acids on lipoprotein would be if they isocalorically replaced cis mono unsaturated fatty acids. In linear regression analysis the plasma LDL to HDL cholesterol ratio increased by 0.055 (95% CI 0.044-0.066) for each % of dietary energy from industrial trans fatty acids replacing cis monounsaturated fatty acids The increase in the LDL to HDL ratio for each % of energy was 0.038 (95% CI 0.012-0.065) for ruminant trans fatty acids, and 0.043 (95% CI 0.012-0.074) for conjugated linoleic acid (p = 0.99 for difference between CLA and industrial trans fatty acids; p = 0.37 for ruminant versus industrial trans fatty acids). Conclusions/Significance: Published data suggest that all fatty acids with a double bond in the trans configuration raise the ratio of plasma LDL to HDL cholesterol. © 2010 Brouwer et al. Source

Schijns V.E.J.C.,Wageningen University | Lavelle E.C.,Trinity College Dublin
Expert Review of Vaccines | Year: 2011

Adjuvants are essential components of most clinically used vaccines. This is because the majority of nonliving vaccines are relatively poor inducers of adaptive immunity unless effective adjuvants are co-administered. Aluminum salts (alum) have been used as adjuvants with great success for almost a century and have been particularly effective at promoting protective humoral immunity. However, alum is not optimally effective for diseases where cell-mediated immunity is required for protection. Furthermore, adjuvants including oil-in-water emulsions have shown improved efficacy for avian influenza protection suggesting that even for diseases where humoral immunity can confer protection, there is scope for developing improved adjuvants. There have been major developments in antigen discovery over the past decade, which has accelerated the vaccine development process for new indications and this demands a new generation of adjuvants that can drive and specifically direct the desired immune responses. A number of systems are under investigation that combine different types of adjuvants into specific formulations with greater activity. Additionally, targeting of vaccines to specific immune cells shows great promise. In the case of cancer and chronic infectious diseases, it may be difficult to develop effective vaccines without blocking immune regulatory pathways, which impede cell-mediated responses. However, increased understanding of immunology and particularly the innate immune system is informing vaccine adjuvant research and consequently driving the development of novel and specifically directed vaccine adjuvant strategies. In this article we address the importance of adjuvants in vaccine development, the known mode of action of specific adjuvants and recent developments in this important field. © 2011 Expert Reviews Ltd. Source

Berhane G.,International Food Policy Research Institute | Gardebroek C.,Wageningen University
American Journal of Agricultural Economics | Year: 2011

Evidence on the long-term impacts of microfinance credit is scarce. We use a unique four-round panel dataset on farm households in northern Ethiopia that had access to microfinance, observed on two key poverty indicators: household consumption and housing improvements. Fixed-effects and random trend models are used to reduce potential selection biases due to time-invariant unobserved heterogeneity and individual trends therein. Results show that borrowing indeed causally increased consumption and housing improvements. A flexible specification that takes into account repeated borrowings also suggests that borrowing has cumulative long-term effects on these outcomes, implying that short-term impact estimates may underestimate credit effects. © 2010 The Author. Published by Oxford University Press on behalf of the Agricultural and Applied Economics Association. All rights reserved. Source

Lubbe A.,Leiden University | Lubbe A.,Wageningen University | Verpoorte R.,Leiden University
Industrial Crops and Products | Year: 2011

Specialty materials such as essential oils, pharmaceuticals, colorants, dyes, cosmetics and biocides are obtained from plants. Many species of medicinal and aromatic plants (MAPs) are cultivated for such industrial uses, but most are still wild collected. The need for renewable sources of industrial products as well as the need to protect plant biodiversity creates an opportunity for farmers to produce such crops. The production of plants as raw material for fine chemicals is different than cultivation of ornamental or food crops. This review attempts to give an overview of the use of MAPs in various industries, as well as trends in the various markets involved. Economic and regulatory issues relevant for such uses of MAP material are also discussed, with a focus on the situation in the European Union. The aim is to provide information to potential producers to help identify interesting MAPs for cultivation. © 2011 Elsevier B.V. Source

Classically, silver (Ag) halides have been used to understand thermodynamic principles of the charging process and the corresponding development of the electrical double layer (EDL). A mechanistic approach to the processes on the molecular level has not yet been carried out using advanced surface complexation modeling (SCM) as applied to metal (hydr)oxide interfaces. Ag halides and metal (hydr)oxides behave quite differently in some respect. The location of charge in the interface of Ag halides is not a priori obvious. For AgI(s), SCM indicates the separation of interfacial charge in which the smaller silver ions are apparently farther away from the surface than iodide. This charge separation can be understood from the surface structure of the relevant crystal faces. Charge separation with positive charge above the surface is due to monodentate surface complex formation of Ag + ions binding to I sites located at the surface. Negative surface charge is due to the desorption of Ag + ions out of the lattice. These processes can be described with the charge distribution (CD) model. The MO/DFT optimized geometry of the complex is used to estimate the value of the CD. SCM reveals the EDL structure of AgI(s), having two Stern layers in series. The inner Stern layer has a very low capacitance (C 1 = 0.15 ± 0.01 F/m 2) in comparison to that of metal (hydr)oxides, and this can be attributed to the strong orientation of the (primary) water molecules on the local electrostatic field of the Ag + and I - ions of the surface (relative dielectric constant ε r ≈ 6). Depending on the extent of water ordering, mineral surfaces may in principle develop a second Stern layer. The corresponding capacitance (C 2) will depend on the degree of water ordering that may decrease in the series AgI (C 2 = 0.57 F/m 2), goethite (C 2 = 0.74 F/m 2), and rutile (C 2 = ∞), as discussed. The charging principles of AgI minerals iodargyrite and miersite may also be applied to minerals with the same surface structure (e.g., sphalerite and würtzite (ZnS)). © 2012 American Chemical Society. Source

Rodenburg J.,Africa Rice Center | Bastiaans L.,Wageningen University
Weed Research | Year: 2011

Parasitic weeds of the genus Striga cause high yield losses in cereal crops across Africa. Host-plant defence against Striga spp. can be an effective control strategy. It ideally consists of resistance, to reduce infection, complemented with tolerance, to mitigate the effects of infection. As resistance against Striga spp. can both minimise yield losses and reduce future infestation levels in infested fields, current breeding efforts are mainly directed towards this trait. Because it is nearly impossible to screen for tolerance on highly resistant genetic lines, tolerance is often neglected. Here, we argue reconsidering the role of tolerance, as recent findings regarding the physiological expression of tolerance offer a promising track for identifying the genetic background of tolerance. Identification of quantitative trait loci for tolerance would facilitate the inclusion of this trait in adapted cultivars with high levels of resistance, where its main role would be to function as a safety net in case the genetically highly variable parasite populations overcome host-plant resistance. Because Striga spp. are mainly prevalent in subsistence farming systems, we consider this an important addition and it is for this reason that we make a plea for a more prominent role of tolerance in present-day integrated management of this weed. © 2011 The Authors. Weed Research © 2011 European Weed Research Society. Source

Schellekens J.,University of Santiago de Compostela | Buurman P.,Wageningen University
Geoderma | Year: 2011

n-Alkane distributions are frequently used as palaeoclimate proxies in ombrotrophic peat deposits. Although n-alkane distributions differ strongly between plant species, n-alkanes are not species-specific molecules. For a proper interpretation, it is important to understand the different abundances of n-alkanes in various plant species as well as the changes that occur when plant litter is transformed to peat. In particular because molecular markers are especially valuable in highly decomposed peat where plant remains are no longer recognizable, it is important to understand the effects of decomposition on n-alkane distributions.The organic matter (OM) of a high-resolution sampled, 9m thick, ombrotrophic peat deposit from Tierra del Fuego was analysed with pyrolysis-gas chromatography/mass spectrometry (pyrolysis-GC/MS). The same samples were analysed for carbon (C) and nitrogen (N) content. Depth profiles of C:N ratio, the summed lignin and summed polysaccharide pyrolysis products, and markers specific for Sphagnum spp., Empetrum rubrum and Nothofagus antarctica, enabled a reconstruction of changes in vegetation composition to be made. This reconstruction was used to examine the validity of the n-C 23 alkane to indicate Sphagnum and the summed long chain n-alkanes (C 29 and C 31) to reflect leaf input of the woody species E. rubrum and N. antarctica.Our results show that even in Sphagnum-dominated peat, the n-alkane distribution is not determined by Sphagnum but by leaf input of E. rubrum and N. antarctica. However, good correlations between the n-C 23 alkane and the Sphagnum marker 4-isopropenylphenol, and between the summed n-C 29 and n-C 31 alkanes and the marker of N. antarctica support that their relative change with depth can be used to indicate the abundance of these species in Sphagnum-dominated peat. In peat with relatively low contributions of Sphagnum, both n-alkane proxies (C 23 and C 29+C 31) reflect the degree of decomposition. We evaluated the influence of Sphagnum dominance, decomposition, and pyrolysis on the n-alkane distributions in peat OM. © 2011 Elsevier B.V. Source

Spiller M.,Wageningen University
Science of the Total Environment | Year: 2016

Sustainability is commonly assessed along environmental, societal, economic and technological dimensions. A crucial aspect of sustainability is that inter-generational equality must be ensured. This requires that sustainability is attained in the here and now as well as into the future. Therefore, what is perceived as ‘sustainable’ changes as a function of societal opinion and technological and scientific progress. A concept that describes the ability of systems to change is adaptive capacity. Literature suggests that the ability of systems to adapt is an integral part of sustainable development. This paper demonstrates that indicators measuring adaptive capacity are underrepresented in current urban water sustainability studies. Furthermore, it is discussed under which sustainability dimensions adaptive capacity indicators are lacking and why. Of the > 90 indicators analysed, only nine are adaptive capacity indicators, of which six are socio-cultural, two technological, one economical and none environmental. This infrequent use of adaptive capacity indicators in sustainability assessments led to the conclusion that the challenge of dynamic and uncertain urban water systems is, with the exception of the socio-cultural dimension, not yet sufficiently reflected in the application of urban water sustainability indicators. This raises concerns about the progress towards urban water systems that can transform as a response variation and change. Therefore, research should focus on developing methods and indicators that can define, evaluate and quantify adaptive capacity under the economic, environmental and technical dimension of sustainability. Furthermore, it should be evaluated whether sustainability frameworks that focus on the control processes of urban water systems are more suitable for measuring adaptive capacity, than the assessments along environmental, economic, socio-cultural and technological dimensions. © 2016 Elsevier B.V. Source

Breteler F.J.,Wageningen University
Plant Ecology and Evolution | Year: 2011

Background and aims - The African genus Isomacrolobium (Leguminosae, Caesalpinioideae) is poorly known. Its species are revised. Methods - Normal practices of herbarium taxonomy have been applied to study all herbarium material available, mainly at BM, BR, COI, FHO, G, K, LBV, MA, MO, OXF, P, WAG, and YA. Key results - Twelve species are recognised, including one new one: I. brachyrhachis from Gabon. All the species are confined to the Guineo-Congolian region. A full taxonomic treatment with key to the species is given. The new species is fully illustrated. The fruits, known of nine species, are illustrated as well. Distribution maps of all taxa are provided. Macrolobium ernae, a synonym of I. obanense, is neotypified. For I. graciliflorum and I. leptorrhachis a lectotype is designated. © 2011 National Botanic Garden of Belgium and Royal Botanical Society of Belgium. Source

van Mierlo B.,Wageningen University
Sustainability: Science, Practice, and Policy | Year: 2012

A proposed strategy to facilitate the use and development of radical new sustainable technologies is the creation of niches. Learning in these niches and the social embedding of learning experiences can stimulate changes in existing sociotechnological regimes. Pilot projects in which new technologies are used may form part of these niches. This article describes the results of a Dutch research project involving photovoltaics on learning within pilot projects and subsequent actions of the participating parties. The central questions are whether and how internal processes, such as open and creative negotiations, foster learning and how such learning relates to subsequent niche developments. The study suggests that pilot projects could encourage both convergent and divergent learning, depending on whether participants' learning experiences and expectations of the new technology start to align. Although the two types of learning can coexist, they seem related to different process conditions. The implication of these findings is that the management of pilot projects to contribute to regime change involves strategic choices about stimulating either the opening or the closing of the novelty's interpretative flexibility. © 2012 van Mierlo. Source

Wosten H.A.B.,University Utrecht | Scholtmeijer K.,Wageningen University
Applied Microbiology and Biotechnology | Year: 2015

Hydrophobins are proteins exclusively produced by filamentous fungi. They self-assemble at hydrophilic-hydrophobic interfaces into an amphipathic film. This protein film renders hydrophobic surfaces of gas bubbles, liquids, or solid materials wettable, while hydrophilic surfaces can be turned hydrophobic. These properties, among others, make hydrophobins of interest for medical and technical applications. For instance, hydrophobins can be used to disperse hydrophobic materials; to stabilize foam in food products; and to immobilize enzymes, peptides, antibodies, cells, and anorganic molecules on surfaces. At the same time, they may be used to prevent binding of molecules. Furthermore, hydrophobins have therapeutic value as immunomodulators and can been used to produce recombinant proteins. © 2015, Springer-Verlag Berlin Heidelberg. Source

Dewulf A.,Wageningen University
Wiley Interdisciplinary Reviews: Climate Change | Year: 2013

The process by which issues, decisions, or events acquire different meanings from different perspectives has been studied as framing. In policy debates about climate change adaptation, framing the adaptation issue is a challenge with potentially far-reaching implications for the shape and success of adaptation projects. From the available literature on how the meaning of climate change adaptation is constructed and debated, three key dimensions of frame differences were identified: (1) the tension between adaptation and mitigation as two contrasting but interrelated perspectives on climate change; (2) the contrast between framing climate change adaptation as a tame technical problem, and framing climate change as a wicked problem of governance; and (3) the framing of climate change adaptation as a security issue, contrasting state security frames with human security frames. It is argued that the study of how climate change adaptation gets framed could be enriched by connecting these dimensions more closely with the following themes in framing research: (1) how decision-making biases that to framing issues as structured technical problems; (2) the process of scale framing by which issues are situated at a particular scale level; and (3) the challenge of dealing with the variety of frames in adaptation processes. WIREs Clim Change 2013, 4:321-330. doi: 10.1002/wcc.227 Conflict of interest: The author has declared no conflicts of interest for this article. For further resources related to this article, please visit the WIREs website.© 2013 John Wiley & Sons, Ltd. Source

Eilmann B.,Swiss Federal Institute of forest | Eilmann B.,Wageningen University | Rigling A.,Swiss Federal Institute of forest
Tree Physiology | Year: 2012

Climate change is challenging forestry management and practices. Among other things, tree species with the ability to cope with more extreme climate conditions have to be identified. However, while environmental factors may severely limit tree growth or even cause tree death, assessing a tree species' potential for surviving future aggravated environmental conditions is rather demanding. The aim of this study was to find a tree-ring-based method suitable for identifying very droughttolerant species, particularly potential substitute species for Scots pine (Pinus sylvestris L.) in Valais. In this inner-Alpine valley, Scots pine used to be the dominating species for dry forests, but today it suffers from high drought-induced mortality. We investigate the growth response of two native tree species, Scots pine and European larch (Larix decidua Mill.), and two non-native species, black pine (Pinus nigra Arnold) and Douglas fir (Pseudotsuga menziesii Mirb. var. menziesii), to drought. This involved analysing how the radial increment of these species responded to increasing water shortage (abandonment of irrigation) and to increasingly frequent drought years. Black pine and Douglas fir are able to cope with drought better than Scots pine and larch, as they show relatively high radial growth even after irrigation has been stopped and a plastic growth response to drought years. European larch does not seem to be able to cope with these dry conditions as it lacks the ability to recover from drought years. The analysis of trees' short-term response to extreme climate events seems to be the most promising and suitable method for detecting how tolerant a tree species is towards drought. However, combining all the methods used in this study provides a complete picture of how water shortage could limit species. © The Author 2011. Source

Duivenvoorde L.P.,Wageningen University
Journal of molecular endocrinology | Year: 2011

High energy intake and, specifically, high dietary fat intake challenge the mammalian metabolism and correlate with many metabolic disorders such as obesity and diabetes. However, dietary restriction (DR) is known to prevent the development of metabolic disorders. The current western diets are highly enriched in fat, and it is as yet unclear whether DR on a certain high-fat (HF) diet elicits similar beneficial effects on health. In this research, we report that HF-DR improves metabolic health of mice compared with mice receiving the same diet on an ad libitum basis (HF-AL). Already after five weeks of restriction, the serum levels of cholesterol and leptin were significantly decreased in HF-DR mice, whereas their glucose sensitivity and serum adiponectin levels were increased. The body weight and measured serum parameters remained stable in the following 7 weeks of restriction, implying metabolic adaptation. To understand the molecular events associated with this adaptation, we analyzed gene expression in white adipose tissue (WAT) with whole genome microarrays. HF-DR strongly influenced gene expression in WAT; in total, 8643 genes were differentially expressed between both groups of mice, with a major role for genes involved in lipid metabolism and mitochondrial functioning. This was confirmed by quantitative real-time reverse transcription-PCR and substantiated by increase in mitochondrial density in WAT of HF-DR mice. These results provide new insights in the metabolic flexibility of dietary restricted animals and suggest the development of substrate efficiency. Source

Biesheuvel P.M.,Wageningen University | Biesheuvel P.M.,Center of Excellence for Sustainable Water Technology
Journal of Colloid and Interface Science | Year: 2011

To describe the velocities of particles such as ions, protein molecules and colloids dispersed or dissolved in a fluid, it is important to also describe the forces acting on the fluid, including pressure gradients and friction of the fluid with the particles and with the porous media through which the fluid flows. To account for this problem, the use of a two-fluid model is described, familiar in the field of fluid mechanics, extended to include osmotic effects. We show how familiar relationships follow in various situations and give examples of combined fluid/particle transport in neutral and charged membranes driven by a combination of electrostatic, diffusional and pressure forces. The analysis shows how the same modeling framework can be generally used both for multidimensional electrokinetic flow through macroscopic channels and around macroscopic objects, as well as for mean-field modeling of transport through porous media such as gels and membranes. © 2010 Elsevier Inc. Source

Genomic selection has become an important tool in the genetic improvement of animals and plants. The objective of this study was to investigate the impacts of breeding value estimation method, reference population structure, and trait genetic architecture, on long-term response to genomic selection without updating marker effects. Three methods were used to estimate genomic breeding values: a BLUP method with relationships estimated from genome-wide markers (GBLUP), a Bayesian method, and a partial least squares regression method (PLSR). A shallow (individuals from one generation) or deep reference population (individuals from five generations) was used with each method. The effects of the different selection approaches were compared under four different genetic architectures for the trait under selection. Selection was based on one of the three genomic breeding values, on pedigree BLUP breeding values, or performed at random. Selection continued for ten generations. Differences in long-term selection response were small. For a genetic architecture with a very small number of three to four quantitative trait loci (QTL), the Bayesian method achieved a response that was 0.05 to 0.1 genetic standard deviation higher than other methods in generation 10. For genetic architectures with approximately 30 to 300 QTL, PLSR (shallow reference) or GBLUP (deep reference) had an average advantage of 0.2 genetic standard deviation over the Bayesian method in generation 10. GBLUP resulted in 0.6% and 0.9% less inbreeding than PLSR and BM and on average a one third smaller reduction of genetic variance. Responses in early generations were greater with the shallow reference population while long-term response was not affected by reference population structure. The ranking of estimation methods was different with than without selection. Under selection, applying GBLUP led to lower inbreeding and a smaller reduction of genetic variance while a similar response to selection was achieved. The reference population structure had a limited effect on long-term accuracy and response. Use of a shallow reference population, most closely related to the selection candidates, gave early benefits while in later generations, when marker effects were not updated, the estimation of marker effects based on a deeper reference population did not pay off. Source

This paper examines recent collaborative efforts by fisheries scientists and representatives from the pelagic fishing industry in Europe to generate a knowledge base to support management of a new fishery for boarfish (Capros aper) in the Northeast Atlantic. The forms of knowledge used and produced in the collaborations were investigated by applying a conceptual framework developed to help understand the detailed dynamics of knowledge exchange in mixed-actor settings. The collaborative initiatives studied were informal and efficient, and they benefited from financial support and co-ordination efforts by the industry actors. Generation of scientific knowledge was given high priority. Tangible collaborative outputs produced between 2010 and 2013 included new scientific insights into boarfish maturity and aging, initiation of an annual boarfish-specific acoustic survey, data to underpin a stock assessment, and two management plan proposals. The study highlights the information requirements that apply for fish stocks managed under the European Common Fisheries Policy and illustrates that the fishing industry can fill important roles in collaborative processes that aim to generate new scientific knowledge to support fisheries management. © 2015 The Authors. Source

Chaowasku T.,Leiden University | Johnson D.M.,Ohio Wesleyan University | van der Ham R.W.J.M.,Leiden University | Chatrou L.W.,Wageningen University
Phytotaxa | Year: 2012

On the basis of molecular phylogenetics, pollen morphology and macromorphology, a new genus of the tribe Miliuseae, Hubera, segregrated from Polyalthia and allied to Miliusa, is established and described. It is characterized by the combination of reticulate tertiary venation of the leaves, axillary inflorescences, a single ovule per ovary and therefore single-seeded monocarps, seeds with a flat to slightly raised raphe, spiniform(-flattened peg) ruminations of the endosperm, and pollen with a finely and densely granular infratectum. Twenty-seven species are accordingly transferred to this new genus. © 2012 Magnolia Press. Source

Delaplane K.S.,University of Georgia | Van Der Steen J.,Wageningen University | Guzman-Novoa E.,University of Guelph
Journal of Apicultural Research | Year: 2013

This paper covers measures of field colony strength, by which we mean population measures of adult bees and brood. There are generally two contexts in which an investigator wishes to measure colony strength: 1. at the beginning of a study as part of manipulations to produce uniform colonies and reduce experimental error and; 2. as response variables during or at the end of an experiment. Moreover, there are two general modes for measuring colony strength: 1. an objective mode which uses empirical measures and; 2. a subjective mode that relies on visual estimates by one or more observers. There is a third emerging mode for measuring colony strength; 3. computer-assisted digital image analysis. A final section deals with parameters that do not directly measure colony strength yet give important indicators of colony state: flight activity at the hive entrance; comb construction; and two proxy measures of colony fitness: production of queen cells and drone brood. Copyright © IBRA 2013. Source

Medema M.H.,Wageningen University | Fischbach M.A.,University of California at San Francisco
Nature Chemical Biology | Year: 2015

Starting with the earliest Streptomyces genome sequences, the promise of natural product genome mining has been captivating: genomics and bioinformatics would transform compound discovery from an ad hoc pursuit to a high-throughput endeavor. Until recently, however, genome mining has advanced natural product discovery only modestly. Here, we argue that the development of algorithms to mine the continuously increasing amounts of (meta)genomic data will enable the promise of genome mining to be realized. We review computational strategies that have been developed to identify biosynthetic gene clusters in genome sequences and predict the chemical structures of their products. We then discuss networking strategies that can systematize large volumes of genetic and chemical data and connect genomic information to metabolomic and phenotypic data. Finally, we provide a vision of what natural product discovery might look like in the future, specifically considering longstanding questions in microbial ecology regarding the roles of metabolites in interspecies interactions. © 2015 Nature America, Inc. All rights reserved. Source

Vredenberg W.J.,Wageningen University | Bulychev A.A.,Moscow State University
Biochimica et Biophysica Acta - Bioenergetics | Year: 2010

Redox transients of chlorophyll P700, monitored as absorbance changes ΔA810, were measured during and after exclusive PSI excitation with far-red (FR) light in pea (Pisum sativum, cv. Premium) leaves under various pre-excitation conditions. Prolonged adaptation in the dark terminated by a short PSII+PSI- exciting light pulse guarantees pre-conditions in which the initial photochemical events in PSI RCs are carried out by cyclic electron transfer (CET). Pre-excitation with one or more 10s FR pulses creates conditions for induction of linear electron transport (LET). These converse conditions give rise to totally different, but reproducible responses of P700- oxidation. System analyses of these responses were made based on quantitative solutions of the rate equations dictated by the associated reaction scheme for each of the relevant conditions. These provide the mathematical elements of the P700 induction algorithm (PIA) with which the distinguishable components of the P700+ response can be resolved and interpreted. It enables amongst others the interpretation and understanding of the characteristic kinetic profile of the P700+ response in intact leaves upon 10s illumination with far-red light under the promotive condition for CET. The system analysis provides evidence that this unique kinetic pattern with a non-responsive delay followed by a steep S-shaped signal increase is caused by a photoelectrochemically controlled suppression of the electron transport from Fd to the PQ-reducing Qr site of the cytb6f complex in the cyclic pathway. The photoelectrochemical control is exerted by the PSI-powered proton pump associated with CET. It shows strong similarities with the photoelectrochemical control of LET at the acceptor side of PSII which is reflected by release of photoelectrochemical quenching of chlorophyll a fluorescence. © 2010 Elsevier B.V. Source

Bardgett R.D.,University of Manchester | Mommer L.,Wageningen University | De Vries F.T.,University of Manchester
Trends in Ecology and Evolution | Year: 2014

Ecologists are increasingly adopting trait-based approaches to understand how community change influences ecosystem processes. However, most of this research has focussed on aboveground plant traits, whereas it is becoming clear that root traits are important drivers of many ecosystem processes, such as carbon (C) and nutrient cycling, and the formation and structural stability of soil. Here, we synthesise emerging evidence that illustrates how root traits impact ecosystem processes, and propose a pathway to unravel the complex roles of root traits in driving ecosystem processes and their response to global change. Finally, we identify research challenges and novel technologies to address them. © 2014 Elsevier Ltd. Source

Vleeshouwers V.G.A.A.,Wageningen University | Oliver R.P.,Curtin University Australia
Molecular Plant-Microbe Interactions | Year: 2014

One of most important challenges in plant breeding is improving resistance to the plethora of pathogens that threaten our crops. The ever-growing world population, changing pathogen populations, and fungicide resistance issues have increased the urgency of this task. In addition to a vital inflow of novel resistance sources into breeding programs, the functional characterization and deployment of resistance also needs improvement. Therefore, plant breeders need to adopt new strategies and techniques. In modern resistance breeding, effectors are emerging as tools to accelerate and improve the identification, functional characterization, and deployment of resistance genes. Since genome-wide catalogues of effectors have become available for various pathogens, including biotrophs as well as necrotrophs, effector-assisted breeding has been shown to be successful for various crops. "Effectoromics" has contributed to classical resistance breeding as well as for genetically modified approaches. Here, we present an overview of how effector-assisted breeding and deployment is being exploited for various pathosystems. © 2014 The American Phytopathological Society. Source

Van Leeuwen H.P.,Wageningen University | Buffle J.,University of Geneva | Town R.M.,University of Southern Denmark
Langmuir | Year: 2012

The chemodynamics of metal complexes with nanoparticulate complexants can differ significantly from that for simple ligands. The spatial confinement of charged sites and binding sites to the nanoparticulate body impacts on the time scales of various steps in the overall complex formation process. The greater the charge carried by the nanoparticle, the longer it takes to set up the counterion distribution equilibrium with the medium. A z+ metal ion (z > 1) in a 1:1 background electrolyte will accumulate in the counterionic atmosphere around negatively charged simple ions, as well as within/around the body of a soft nanoparticle with negative structural charge. The rate of accumulation is often governed by diffusion and proceeds until Boltzmann partition equilibrium between the charged entity and the ions in the medium is attained. The electrostatic accumulation proceeds simultaneously with outer-sphere and inner-sphere complex formation. The rate of the eventual inner-sphere complex formation is generally controlled by the rate constant of dehydration of the metal ion, k w. For common transition metal ions with moderate to fast dehydration rates, e.g., Cu 2+, Pb 2+, and Cd 2+, it is shown that the ionic equilibration with the medium may be the slower step and thus rate-limiting in their overall complexation with nanoparticles. © 2011 American Chemical Society. Source

Hoitink A.J.F.,Wageningen University | Jay D.A.,Portland State University
Reviews of Geophysics | Year: 2016

Tidal rivers are a vital and little studied nexus between physical oceanography and hydrology. It is only in the last few decades that substantial research efforts have been focused on the interactions of river discharge with tidal waves and storm surges into regions beyond the limit of salinity intrusion, a realm that can extend inland hundreds of kilometers. One key phenomenon resulting from this interaction is the emergence of large fortnightly tides, which are forced long waves with amplitudes that may increase beyond the point where astronomical tides have become extinct. These can be larger than the linear tide itself at more landward locations, and they greatly influence tidal river water levels and wetland inundation. Exploration of the spectral redistribution and attenuation of tidal energy in rivers has led to new appreciation of a wide range of consequences for fluvial and coastal sedimentology, delta evolution, wetland conservation, and salinity intrusion under the influence of sea level rise and delta subsidence. Modern research aims at unifying traditional harmonic tidal analysis, nonparametric regression techniques, and the existing understanding of tidal hydrodynamics to better predict and model tidal river dynamics both in single-thread channels and in branching channel networks. In this context, this review summarizes results from field observations and modeling studies set in tidal river environments as diverse as the Amazon in Brazil, the Columbia, Fraser and Saint Lawrence in North America, the Yangtze and Pearl in China, and the Berau and Mahakam in Indonesia. A description of state-of-the-art methods for a comprehensive analysis of water levels, wave propagation, discharges, and inundation extent in tidal rivers is provided. Implications for lowland river deltas are also discussed in terms of sedimentary deposits, channel bifurcation, avulsion, and salinity intrusion, addressing contemporary research challenges. ©2016. American Geophysical Union. All Rights Reserved. Source

Both at the individual and health system levels, the burden of complex illnesses associated with and which rise in mid- to later life, such as cancer, is expected to increase further. The advent of personalized medicine, or the use of a patient's genetic profile to guide medical decisions, is touted to substantially improve drug tolerance and efficacy and, in so doing, also improve the effectiveness and efficiency of oncological care. Amidst the hype and hope surrounding personalized cancer care, there is increasing concern about its unnecessary, unintended effects especially with regards to the financial burden of targeted therapies using specialty drugs. In this paper, we take a patient-centered perspective on the therapeutic benefits of personalized medicine as well as the limitations of current practice and its psychological and financial toxicities by focusing on advanced-stage lung cancer. We argue that the modest clinical benefits of targeted therapy, premium prices for many specialty drugs and the narrow focus on the genetic constitution of individual patients run the risk of undercutting personalized lung cancer care's contribution to realizing health and non-health outcomes. We discuss the contribution of grading the financial burden of treatment and seamless integration of palliative care as key action areas regarding patients' access to and appropriateness of care given patients' needs and preferences. © 2015 Elsevier Ireland Ltd. Source

Heuvelink G.B.M.,Wageningen University | Griffith D.A.,University of Texas at Dallas
Geographical Analysis | Year: 2010

Many branches within geography deal with variables that vary not only in space but also in time. Therefore, conventional geostatistics needs to be extended with methods that estimate and quantify spatiotemporal variation and use it in spatiotemporal interpolation and stochastic simulation. This article briefly summarizes the main concepts of space-time geostatistics. Kriging in space and time can be done in much the same way as it is in a purely spatial setting. The main difficulties are in defining a realistic stochastic model that is assumed to have generated data and in characterizing and estimating the space-time correlation of that model. This article uses a model-based geostatistical approach to characterize space-time variability. The space-time variable of interest is treated as a sum of independent stationary spatial, temporal, and spatiotemporal components, which leads to a sum-metric space-time variogram model. Methods are illustrated with a case study of space-time interpolation of monthly averages of detected background radiation for a 5-year period in four German states. © 2010 The Ohio State University. Source

Haijema R.,Wageningen University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

The management of inventories of perishable products with a short maximal shelf life takes a good issuing policy next to a good ordering policy. Ordering policies of non-perishables are well studied in literature and implemented in Automated Store Ordering (ASO) systems and Computer Assisted Ordering (CAO) systems. These ordering policies are stock-level dependent and do not take the product ages into account. As a consequence when applied to perishable products they do not anticipate expected future outdating of products and thus result in unnecessary outdating and shortages. Improved ordering policies are proposed in the literature but hardly implemented in ASO and CAO systems as these are designed for the management of non-perishables. Without changing the order policies of such systems one may reduce outdating and shortages by issuing the products in a sophisticated way. We present therefore a stochastic model that is solved by stochastic dynamic programming. © 2011 Springer-Verlag. Source

Olivieri G.,University of Naples Federico II | Olivieri G.,Wageningen University | Salatino P.,University of Naples Federico II | Marzocchella A.,University of Naples Federico II
Journal of Chemical Technology and Biotechnology | Year: 2014

Over the past ten years a great deal of literature has focused on the biotechnological potential of microalgal commercial applications, mainly in the field of biofuel production. However, the biofuel production is not yet competitive, mainly due to the incidence of the photobioreactor technology on the process cost. Besides, major advances in classic photobioreactor design, several novel configurations have been proposed in the last 20 years to improve their performance expressed in terms of light absorption, biomass productivity, light to biomass yield and photosynthetic efficiency. This review aims at analyzing and classifying the most recent advances and the several novel approaches to the design, development, control and modeling of photobioreactors. The diverse approaches are grouped considering irradiance strategies, multiphase hydrodynamics, mass transfer mechanisms, modeling approaches and control strategies. Some innovative applications of the photobioreactor technology are also reported. © 2013 Society of Chemical Industry. Source

Van Der Sman R.G.M.,Wageningen University
Computer Physics Communications | Year: 2013

We have investigated the performance of an alternative wetting boundary condition for complex geometries in a phase field Lattice Boltzmann scheme, which is an alternative to the commonly used formulation by Yeomans and coworkers. Though our boundary condition is much simpler in its implementation, all investigated schemes show proper droplet spreading behaviour following the Cox-Voinov law. Still, numerical artefacts like spurious velocities or chequer board effects in the pressure field can be significantly reduced by the use of a two-relaxation-time (TRT) scheme, likewise recent studies by the Yeomans group. The outstanding property of our implementation is the presence of an (artificial) thin wetting layer, which influences the relation between the saturation (Sw) and capillary pressure pcap in channels with irregular polygonal cross section. The pcap(Sw) relation from our simulation follows the shifted-Young-Laplace (sYL) law, showing that the physics of this wetting layer is similar to precursor films due to Van der Waals forces. With the knowledge of the thickness of the wetting layer, simulation results can be translated back to realistic pore configurations with thinner wetting layers. © 2013 Elsevier B.V. All rights reserved. Source

De Groot L.C.P.G.M.,Wageningen University
Proceedings of the Nutrition Society | Year: 2016

The ageing process is influenced by a variety of factors, including extrinsic, malleable lifestyle variables. The present paper deals with the epidemiological evidence for the role of dietary patterns and key nutritional concerns in relation to survival and ageing-related disorders that present themselves in later life. Healthful dietary patterns appear to be most relevant in old age. Specific nutritional concerns are related to vitamin D, vitamin B12 and protein malnutrition. An important challenge to further expand the knowledge base is currently addressed by the NuAge project, acknowledging the complexity of the ageing process and integrating different dimensions of research into human healthy ageing. In the meantime, reversing poor adherence to existing guidelines for a healthy diet remains a first challenge in public health nutritional practices. Copyright © The Author 2016. Source

The introduction of relevant food safety changes in legislation, like time-temperature criteria for pasteurisation and sterilisation, microbiological criteria, HACCP and FSOs, generally took several decades. All these approaches have helped to define specific targets or systems to improve the management of food safety. More and more the measures could be related to specific efficiency in public health protection. With the use of quantitative risk assessment, theoretically the effect of all interventions on the final risk can be determined, which can help to design the appropriate controls in the food safety management system. In such an assessment in practice, however results have understandably large variability and also uncertainty. There is large variability and uncertainty in the biological parts of the assessment, the dose response (infectivity, human susceptibility) the micro-organism kinetics in the chain (growth, inactivation, stress response) and also in the more technological parts, the conditions in the chain and the consumer behaviour. Often the results of risk assessments are probability distributions of the variability in illness probability, also sometimes represented with their uncertainty. To make a link from these distributions to managerial decisions, that need to be black and white, should not be considered the job of risk managers. This link needs investment from both the assessor and the manager. © 2015 Elsevier B.V. Source

Sagis L.M.C.,Wageningen University
Reviews of Modern Physics | Year: 2011

The dynamic properties of interfaces often play a crucial role in the macroscopic dynamics of multiphase soft condensed matter systems. These properties affect the dynamics of emulsions, of dispersions of vesicles, of biological fluids, of coatings, of free surface flows, of immiscible polymer blends, and of many other complex systems. The study of interfacial dynamic properties, surface rheology, is therefore a relevant discipline for many branches of physics, chemistry, engineering, and life sciences. In the past three to four decades a vast amount of literature has been produced dealing with the rheological properties of interfaces stabilized by low molecular weight surfactants, proteins, (bio)polymers, lipids, colloidal particles, and various mixtures of these surface active components. In this paper recent experiments are reviewed in the field of surface rheology, with particular emphasis on the models used to analyze surface rheological data. Most of the models currently used are straightforward generalizations of models developed for the analysis of rheological data of bulk phases. In general the limits on the validity of these generalizations are not discussed. Not much use is being made of recent advances in nonequilibrium thermodynamic formalisms for multiphase systems, to construct admissible models for the stress-deformation behavior of interfaces. These formalisms are ideally suited to construct thermodynamically admissible constitutive equations for rheological behavior that include the often relevant couplings to other fluxes in the interface (heat and mass), and couplings to the transfer of mass from the bulk phase to the interface. In this review recent advances in the application of classical irreversible thermodynamics, extended irreversible thermodynamics, rational thermodynamics, extended rational thermodynamics, and the general equation for the nonequilibrium reversible-irreversible coupling formalism to multiphase systems are also discussed, and shown how these formalisms can be used to generate a wide range of thermodynamically admissible constitutive models for the surface stress tensor. Some of the generalizations currently in use are shown to have only limited validity. The aim of this review is to stimulate new developments in the fields of experimental surface rheology and constitutive modeling of multiphase systems using nonequilibrium thermodynamic formalisms and to promote a closer integration of these disciplines. © 2011 American Physical Society. Source

Charpentier E.,Helmholtz Center for Infection Research | Charpentier E.,Umea University | Charpentier E.,Hannover Medical School | Richter H.,Helmholtz Center for Infection Research | And 2 more authors.
FEMS Microbiology Reviews | Year: 2015

CRISPR-Cas is an RNA-mediated adaptive immune system that defends bacteria and archaea against mobile genetic elements. Short mature CRISPR RNAs (crRNAs) are key elements in the interference step of the immune pathway. A CRISPR array composed of a series of repeats interspaced by spacer sequences acquired from invading mobile genomes is transcribed as a precursor crRNA (pre-crRNA) molecule. This pre-crRNA undergoes one or two maturation steps to generate the mature crRNAs that guide CRISPR-associated (Cas) protein(s) to cognate invading genomes for their destruction. Different types of CRISPR-Cas systems have evolved distinct crRNA biogenesis pathways that implicate highly sophisticated processing mechanisms. In Types I and III CRISPR-Cas systems, a specific endoribonuclease of the Cas6 family, either standalone or in a complex with other Cas proteins, cleaves the pre-crRNA within the repeat regions. In Type II systems, the trans-acting small RNA (tracrRNA) base pairs with each repeat of the pre-crRNA to form a dual-RNA that is cleaved by the housekeeping RNase III in the presence of the protein Cas9. In this review, we present a detailed comparative analysis of pre-crRNA recognition and cleavage mechanisms involved in the biogenesis of guide crRNAs in the three CRISPR-Cas types. © FEMS 2015. Source

De Vries R.,Wageningen University
Journal of Chemical Physics | Year: 2011

A large literature exists on modeling the influence of sequence-specific DNA-binding proteins on the shape of the DNA double helix in terms of one or a few fixed constraints. This approach is inadequate for the many proteins that bind DNA sequence independently, and that are present in very large quantities rather than as a few copies, such as the nucleoid proteins in bacterial cells. The influence of such proteins on DNA configurations is better modeled in terms of a great number of mobile constraints on the DNA. Types of constraints that mimic the influence of various known non-specifically DNA binding proteins include DNA bending, wrapping, and bridging. Using Monte-Carlo simulations, we here investigate the influence of (non-interacting) mobile DNA-protein-DNA bridges on the configurations of a 1000 bp piece of linear DNA, for both homogeneous DNA and DNA with an intrinsic planar bend. Results are compared to experimental data on the bacterial nucleoid protein H-NS that forms DNA-protein-DNA bridges. In agreement with data on H-NS, we find very strong positioning of DNA-protein-DNA bridges in the vicinity of planar bends. H-NS binds to DNA very cooperatively, but for non-interacting bridges we only find a moderate DNA-induced clustering. Finally, it has been suggested that H-NS is an important contributor to the extreme condensation of bacterial DNA into a nucleoid structure, but we find only a moderate compaction of DNA coils with increasing numbers of non-interacting bridges. Our results illustrate the importance of quantifying the various effects on DNA configurations that have been proposed for proteins that bind DNA sequence independently. © 2011 American Institute of Physics. Source

Fei M.,Netherlands Institute of Ecology | Gols R.,Wageningen University | Harvey J.A.,Netherlands Institute of Ecology
Journal of Animal Ecology | Year: 2014

Summary: Spatial-temporal realism is often missing in many studies of multitrophic interactions, which are conducted at a single time frame and/or involving interactions between insects with a single species of plant. In this scenario, an underlying assumption is that the host-plant species is ubiquitous throughout the season and that the insects always interact with it. We studied interactions involving three naturally occurring wild species of cruciferous plants, Brassica rapa, Sinapis arvensis and Brassica nigra, that exhibit different seasonal phenologies, and a multivoltine herbivore, the large cabbage white butterfly, Pieris brassicae, and its gregarious endoparasitoid wasp, Cotesia glomerata. The three plants have very short life cycles. In central Europe, B. rapa grows in early spring, S. arvensis in late spring and early summer, and B. nigra in mid to late summer. P. brassicae generally has three generations per year, and C. glomerata at least two. This means that different generations of the insects must find and exploit different plant species that may differ in quality and which may be found some distance from one another. Insects were either reared on each of the three plant species for three successive generations or shifted between generations from B. rapa to S. arvensis to B. nigra. Development time from neonate to pupation and pupal fresh mass were determined in P. brassicae and egg-to-adult development time and body mass in C. glomerata. Overall, herbivores performed marginally better on S. arvensis and B. nigra plants than on B. rapa plants. Parasitoids performance was closely tailored with that of the host. Irrespective as to whether the insects were shifted to a new plant in successive generations or not, development time of P. brassicae and C. glomerata decreased dramatically over time. Our results show that there were some differences in insect development on different plant species and when transferred from one species to another. However, all three plants were of generally high quality in terms of insect performance. We discuss ecological and evolutionary constraints on insects that must search in new habitats for different plant species over successive generations. © 2013 The Authors. Journal of Animal Ecology © 2013 British Ecological Society. Source

Kersten S.,Wageningen University
Results and Problems in Cell Differentiation | Year: 2010

Metabolic and immune-related pathways intersect at numerous levels. Their common regulation is effectuated by several hormonal signaling routes that involve specific nuclear hormone receptors and adipokines. Glucocorticoids and leptin are hormones that play a key role in coordinating energy metabolism and food-seeking behavior during energy deficiency as does the nuclear hormone receptor Peroxisome Proliferator Activated Receptor α (PPARα). Importantly, the glucocorticoid, leptin, and PPARα signaling routes share a profound role in governing inflammation and other immune-related processes. Using specific examples, this chapter aims at illustrating the interplay between metabolism and immunity/inflammation by discussing common endocrine and transcriptional regulators of metabolism and inflammation and by highlighting the interaction between macrophages and metabolically active cells in liver and adipose tissue. Convergence of metabolic and immune signaling is likely at least partially driven by the evolutionary need during times of food insufficiency to minimize loss of energy to processes that are temporarily nonessential to the survival of the species. © 2011 Springer Berlin Heidelberg. Source

Shankaranarayanan P.,Institute Of Genetique Et Of Biologie Moleculaire Et Cellulaire | Mendoza-Parra M.-A.,Institute Of Genetique Et Of Biologie Moleculaire Et Cellulaire | Van Gool W.,Institute Of Genetique Et Of Biologie Moleculaire Et Cellulaire | Trindade L.M.,Wageningen University | Gronemeyer H.,Institute Of Genetique Et Of Biologie Moleculaire Et Cellulaire
Nature Protocols | Year: 2012

Linear amplification of DNA (LinDA) by T7 polymerase is a versatile and robust method for generating sufficient amounts of DNA for genome-wide studies with minute amounts of cells. LinDA can be coupled to a great number of global profiling technologies. Indeed, chromatin immunoprecipitation coupled to massive parallel sequencing (ChIP-seq) has been achieved for transcription factors and epigenetic modification of chromatin histones with 1,000 to 5,000 cells. LinDA largely simplifies reChIP-seq experiments to monitor co-binding at chromatin target sites. The single-tube design of LinDA is ideal for handling ultrasmall amounts of DNA (<30 pg) and is compatible with automation. The actual hands-on working time is less than 6 h with one overnight reaction. The present protocol describes all materials and critical steps, and provides examples and controls for LinDA. Applications of LinDA for genome-wide analyses of biobank samples and for the study of chromatin conformation and nuclear architecture are in progress. © 2012 Nature America, Inc. All rights reserved. Source

Zhulina E.B.,RAS Institute of Macromolecular Compounds | Leermakers F.A.M.,Wageningen University
Biophysical Journal | Year: 2010

Applying self-consistent field theory, we consider a coarse-grained model for the polymerlike projections of neurofilament (NF) proteins that form a brush structure around neurofilaments. We focus on effects of molecular composition, which is the relative occurrence of NF-H, NF-M, and NF-L proteins, on the organization of NF projection domains. We consider NF brushes with selectively truncated projections, and with a varied ratio L:H:M of constituent tails. Our conclusion is that the NF brush structure Is remarkably tolerant with respect to the variation In M and H chains. Results compare favorably with experimental data on model animals, provided that due attention is paid on the level of phosphorylation of the KSP repeats. © 2010 by the Biophysical Society. Source

Bosma M.,Maastricht University | Kersten S.,Wageningen University | Hesselink M.K.C.,Maastricht University | Schrauwen P.,Maastricht University
Progress in Lipid Research | Year: 2012

Ectopic fat accumulation has been linked to lipotoxic events, including the development of insulin resistance in skeletal muscle. Indeed, intramyocellular lipid storage is strongly associated with the development of type 2 diabetes. Research during the last two decades has provided evidence for a role of lipid intermediates like diacylglycerol and ceramide in the induction of lipid-induced insulin resistance. However, recently novel data has been gathered that suggest that the relation between lipid intermediates and insulin resistance is less straightforward than has been previously suggested, and that there are several routes towards lipid-induced insulin resistance. For example, research in this field has shifted towards imbalances in lipid metabolism and lipid droplet dynamics. Next to imbalances in key lipogenic and lipolytic proteins, lipid droplet coat proteins appear to be essential for proper intramyocellular lipid storage, turnover and protection against lipid-induced insulin resistance. Here, we discuss the current knowledge on lipid-induced insulin resistance in skeletal muscle with a focus on the evidence from human studies. Furthermore, we discuss the available data that provides supporting mechanistic information. © 2011 Elsevier Ltd. All rights reserved. Source

Ali F.,University Putra Malaysia | Ismail A.,University Putra Malaysia | Kersten S.,Wageningen University
Molecular Nutrition and Food Research | Year: 2014

Obesity and related metabolic diseases (e.g., type 2 diabetes, cardiovascular diseases, and hypertension) are the most prevailing nutrition-related issues in the world. An emerging feature of obesity is their relationship with chronic inflammation that begins in white adipose tissue and eventually becomes systemic. One potential dietary strategy to reduce glucose intolerance and inflammation is consumption of polyphenol-rich cocoa-like cocoa or their by-products. In vitro as well as in vivo data indicate that cocoa polyphenols (CPs) may exhibit antioxidant and anti-inflammatory properties. Polyphenols commonly found in cocoa have been reported to regulate lipid metabolism via inducing metabolic gene expression or activating transcription factors that regulate the expression of numerous genes, many of which play an important role in energy metabolism. Currently, several molecular targets (e.g., nuclear factor Kappa B, activated protein-1, peroxisome proliferator-activated receptors, liver X receptors, and adiponectin gene) have been identified, which may explain potential beneficial obesity-associated diseases effects of CPs. Further studies have been performed regarding the protective effects of CPs against metabolic diseases by suppressing transcription factors that antagonize lipid accumulation. Thus, polyphenols-rich cocoa products may diminish obesity-mediated metabolic diseases by multiple mechanisms, thereby attenuating chronic inflammation. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Poelman E.H.,Wageningen University | Kessler A.,Cornell University
Trends in Plant Science | Year: 2016

Plants need to defend themselves against a diverse and dynamic herbivore community. Such communities may be shaped by keystone herbivores that through their feeding alter the plant phenotype as well as the likelihood of attack by other herbivores. Here, we discuss such herbivores that have a large effect on the interaction network structure with associated fitness consequences for the plant, as dominant agents of selection on plant defense traits. Merging the keystone herbivore concept with plant fitness and trait selection frameworks will provide an approach to identify which herbivores drive selection in complex multispecies interactions in natural and agricultural systems. Keystone herbivores affect the composition of plant-associated communities through plant-mediated species interactions and thus affect the integrative effect of the herbivore community on plant fitness.Through their role in mediating the outcomes of plant-herbivore community interactions, keystone herbivores are expected to be major agents of natural selection on constitutive and induced direct and indirect resistance although they may individually not significantly affect plant fitness. Thus, they are key to understanding evolution of plant defenses.Identifying keystone herbivores and measuring their plant fitness effects would be equivalent to identifying the fitness effect of plant-associated interaction networks and provide a shortcut to understanding diffuse (co)-evolution. © 2016 Elsevier Ltd. Source

Hiemstra T.,Wageningen University
Geochimica et Cosmochimica Acta | Year: 2013

Ferrihydrite (Fh) is an yet enigmatic nano Fe(III)-oxide material, omnipresent in nature that can bind ions in large quantities, regulating bioavailability and ion mobility. Although extensively studied, to date no proper view exists on the surface structure and composition, while it is of vital importance to our understanding of ion complexation in terrestrial and aquatic systems. Here, the surface structure of Fh is elucidated in relation to that of the mineral core, showing a unique surface composition differing from the mineral core. The mineral core is basically defect-free for all Fh particles. Key for understanding Fh is the very large contribution of the surface as an " inter-phase" The surface of Fh is depleted by two specific types of polyhedra (Fe2,Fe3). Surface depletion (SD) explains the observed particle size dependency of the (a) Pair Distribution Function (PDF) derived from High Energy X-ray total Scattering (HEXS), (b) thermogravimetric water content, and (c) mass density. It also explains the isotopic 57Fe exchange ratio. Due to surface groups, two-line Fh particles are water rich but its mineral core is hydrogen poor.The SD model elucidates the surface structure of crystal faces of idealized Fh such as the 1-10 and 1-11 type of faces that may strongly contribute (e.g. ∼75±10%) to the total surface area. These faces are terminated by protruding Fe1 octahedra, creating the singly-coordinated FeOH(H) groups at the Fh surface. Alternating rows of Fe1 octahedra with singly-coordinated surface groups enable the formation of either double corner (2C) or edge (1E) surface complexes. For Fh, the site densities derived are much higher than for goethite. In combination with the high surface area, it makes Fh to an extremely reactive natural phase. © 2012 Elsevier Ltd. Source

Town R.M.,University of Southern Denmark | Van Leeuwen H.P.,Wageningen University
Environmental Chemistry | Year: 2014

Environmental context Sorbing nanoparticles can have a significant effect on the speciation of small ions and molecules in the environment. The reactivity of nanoparticulate-bound species can differ significantly from that of their molecular or colloidal counterparts. We present a conceptual framework that describes the chemodynamics and lability of nanoparticulate metal complexes over a wide range of experimental timescales and environmental conditions. Abstract An inherent property of a dispersion of charged nanoparticles is that their charges and reactive sites are spatially confined to the particle body which is at a different potential from that in the bulk medium. This feature has important consequences for the reactivity of nanoparticulate complexants: the diffusive rate of reactant supply is lower as compared to molecular complexants, whereas the local concentration of reactant ions may be enhanced if the particle's electric field has the opposite charge sign. These effects are most dramatic for soft nanoparticles for which the electrostatic accumulation mechanisms operate on a 3-D level. We show how the interplay of these effects governs the reactivity of charged nanoparticulate metal complexes (M-NPs) at the surface of an analytical speciation sensor. A theoretical framework is presented that describes the lability of M-NP species over a range of effective timescales for different electrochemical and other dynamic speciation analysis techniques. The concepts are illustrated by electrochemical stripping data on metal complexes with natural soft nanoparticles of humic acid. © 2014 CSIRO. Source

Van Huis A.,Wageningen University
Annual Review of Entomology | Year: 2013

With a growing world population and increasingly demanding consumers, the production of sufficient protein from livestock, poultry, and fish represents a serious challenge for the future. Approximately 1,900 insect species are eaten worldwide, mainly in developing countries. They constitute quality food and feed, have high feed conversion ratios, and emit low levels of greenhouse gases. Some insect species can be grown on organic side streams, reducing environmental contamination and transforming waste into high-protein feed that can replace increasingly more expensive compound feed ingredients, such as fish meal. This requires the development of cost-effective, automated mass-rearing facilities that provide a reliable, stable, and safe product. In the tropics, sustainable harvesting needs to be assured and rearing practices promoted, and in general, the food resource needs to be revalorized. In the Western world, consumer acceptability will relate to pricing, perceived environmental benefits, and the development of tasty insect-derived protein products. © 2013 by Annual Reviews. All rights reserved. Source

Arts B.,Wageningen University
Forest Policy and Economics | Year: 2012

This paper provides an overview of theories currently used in forest policy analysis. It also examines trends in theory use over time. The aim is to assess whether the sub-discipline of forest policy analysis deviates from the "mother discipline" of the policy sciences, and if so, how and to what extent. In addition, theory use in the journal Forest Policy and Economics is ranked. The paper can help researchers identify relevant theories for structuring their data collection and analysis on forest policy. It concludes that forest policy analysis has become rather "current" (i.e. well-embedded in the mother discipline), but that it only gained this status relatively recently. © 2010 Elsevier B.V. Source

Zielinska K.,Wageningen University
Environmental Chemistry | Year: 2014

Solid phase microextraction (SPME) is applied in the speciation analysis of the hydrophobic compound triclosan in an aqueous medium containing sorbing SiO2 nanoparticles (NPs). It is found that these NPs, as well as their complexes with triclosan, partition between the bulk medium and the solid phase poly(dimethylsiloxane) (PDMS). Furthermore, they appear to aggregate at the PDMS-water interface. The total triclosan concentration in the solid phase thus includes both the free and the NP-bound forms. Proper computation of the analyte concentration in the sample medium requires (i) consideration of the speciation of triclosan inside the solid phase and (ii) elimination of the effects of aggregation of NP complexes at the solid phase-bulk medium interface. Possible solutions include application of a protective membrane with pore size smaller than the NP diameter. This allows measurement of the free triclosan concentration, albeit at the cost of longer accumulation times and loss of kinetic information on the triclosan-NP complex. Journal compilation © CSIRO 2014. Source

Wientjes Y.C.J.,Animal Breeding and Genomics Center | Wientjes Y.C.J.,Wageningen University | Veerkamp R.F.,Animal Breeding and Genomics Center | Calus M.P.L.,Animal Breeding and Genomics Center
Genetics | Year: 2013

Although the concept of genomic selection relies on linkage disequilibrium (LD) between quantitative trait loci and markers, reliability of genomic predictions is strongly influenced by family relationships. In this study, we investigated the effects of LD and family relationships on reliability of genomic predictions and the potential of deterministic formulas to predict reliability using population parameters in populations with complex family structures. Five groups of selection candidates were simulated by taking different information sources from the reference population into account: (1) allele frequencies, (2) LD pattern, (3) haplotypes, (4) haploid chromosomes, and (5) individuals from the reference population, thereby having real family relationships with reference individuals. Reliabilities were predicted using genomic relationships among 529 reference individuals and their relationships with selection candidates and with a deterministic formula where the number of effective chromosome segments (Me) was estimated based on genomic and additive relationship matrices for each scenario. At a heritability of 0.6, reliabilities based on genomic relationships were 0.002 ±0.0001 (allele frequencies), 0.022 ± 0.001 (LD pattern), 0.018 ±0.001 (haplotypes), 0.100 ± 0.008 (haploid chromosomes), and 0.318 ± 0.077 (family relationships). At a heritability of 0.1, relative differences among groups were similar. For all scenarios, reliabilities were similar to predictions with a deterministic formula using estimated Me. So, reliabilities can be predicted accurately using empirically estimated Me and level of relationship with reference individuals has a much higher effect on the reliability than linkage disequilibrium per se. Furthermore, accumulated length of shared haplotypes is more important in determining the reliability of genomic prediction than the individual shared haplotype length. © 2013 by the Genetics Society of America. Source

Gudding R.,Norwegian Veterinary Institute | Van Muiswinkel W.B.,Wageningen University
Fish and Shellfish Immunology | Year: 2013

Disease prevention and control are crucial in order to maintain a sustainable aquaculture, both economically and environmentally. Prophylactic measures based on stimulation of the immune system of the fish have been an effective measure for achieving this goal. Immunoprophylaxis has become an important part in the successful development of the fish-farming industry. The first vaccine for aquaculture, a vaccine for prevention of yersiniosis in salmonid fish, was licensed in USA in 1976. Since then the use of vaccines has expanded to new countries and new species simultaneous with the growth of the aquaculture industry. This paper gives an overview of the achievements in fish vaccinology with particular emphasis on immunoprophylaxis as a practical tool for a successful development of bioproduction of aquatic animals. © 2013 Elsevier Ltd. Source

Bracke M.B.M.,Wageningen University
Applied Animal Behaviour Science | Year: 2011

Wallowing, i.e. coating the body surface with mud, is a natural behaviour of pigs, commonly observed in feral pigs and wild boar, but rarely provided for in current housing systems for domestic pigs. Furthermore, in welfare science the subject has not been receiving much attention. This paper reviews wallowing in pigs and related species. The behaviour is described and its motivational basis is examined. Underlying the review was a literature search for scientific citations. In total 48 papers were identified containing citations about wallowing behaviour in pigs and wild boar, and 12 papers contained citations about wallowing in related species. Wallowing is observed in many related species including rhino's, elephants, bovids (e.g. American bison) and deer. Pigs also share several taxonomic characteristics with water-loving mammals such as water buffalo's, hippo's and whales. The common perception is that pigs wallow mainly for cooling, sunburn protection and the removal of ecto-parasites. Little scientific evidence exists for other functions than thermoregulation. Pigs lack functional sweat glands and wallowing in mud is an effective behavioural control mechanism in pigs to prevent hyperthermia. Wallowing, however, may also serve other functions, e.g. in scent-marking and sexual behaviour. In addition, wallowing in pigs, like dustbathing in poultry, may be indicative of positive welfare and, perhaps, the performance of the behaviour is 'hardwired' and rewarding in itself. If so, wallowing could be an important element of a good life in pigs. © 2011 Elsevier B.V. Source

Hofstra N.,Wageningen University
Current Opinion in Environmental Sustainability | Year: 2011

Climate change, among other factors, will impact waterborne pathogen concentrations in surface water worldwide, possibly increasing the risk of diseases caused by these pathogens. So far, the impacts are only determined qualitatively and thorough quantitative estimates of future pathogen concentrations have not yet been made. This review shows how changes in temperature and precipitation influence pathogen concentrations and gives opportunities to quantitatively explore the impact of climate change on pathogen concentrations using examples from ecological and hydrological modelling, already available statistical and process-based pathogen models and climate change scenarios. Such applications could indicate potential increased waterborne pathogen concentrations and guide further research. © 2011 Elsevier B.V. Source

Pijlman G.P.,Wageningen University
Biotechnology Journal | Year: 2015

Arthropod-borne arboviruses form a continuous threat to human and animal health, but few arboviral vaccines are currently available. Advances in expression technology for complex, enveloped virus-like particles (eVLPs) create new opportunities to develop potent vaccines against pathogenic arboviruses. In this short review, I highlight the successes and challenges in eVLP production for members of the three major arbovirus families: Flaviviridae (e.g., dengue, West Nile, Japanese encephalitis); Bunyaviridae (e.g., Rift Valley fever); and Togaviridae (e.g., chikungunya). The results from pre-clinical testing will be discussed as well as specific constraints to the large-scale manufacture and purification of eVLPs, which are complex assemblies of membranes and viral glycoproteins. Insect cells emerge as ideal substrates for correct arboviral glycoprotein folding and posttranslational modification to yield high quality eVLPs. Furthermore, baculovirus expression in insect cell culture is scalable and has a proven safety record in industrial human and veterinary vaccine manufacturing. In conclusion, eVLPs produced in insect cells using modern biotechnology have a realistic potential to be used in novel vaccines against arboviral diseases. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

This article engages with the trajectory of urban participation in Recife, Brazil, from its start as a governance system aimed at ensuring the right of the poor to the city, to the introduction by the Workers' Party of participatory budgeting. I argue that participation is used by the state in order to include populations within governmental structures while the poor struggle for the right to belong to the city. Drawing on Alain Badiou's ontology of multiplicity I contend that the urban situation is grounded in inconsistency, as manifested in the existence of a category of people who "sit at the edge of the void", that neither is included nor belongs. I conclude that the popular mobilizations in Recife in the 1980s constituted a true emancipatory event that exposed the divisions of the city, the existence of a fundamental wrong, and that proclaimed the right of the excluded to the city. © Antipode Foundation. Source

Van Der Sman R.G.M.,Wageningen University
Computer Physics Communications | Year: 2010

We introduce a novel multiple-relaxation time (modified MRT) Lattice Boltzmann scheme for simulation of confined suspension flow. Via careful tuning of the free eigenvalues of the collision operator we can substantially reduce the error in the so-called hydrodynamic radius. Its performance has been compared to that of the TRT scheme for several benchmark problems. We have found that the optimal value of the free eigenvalue depends on the curvature of the solid-fluid interfaces. Hence, we have investigated suspension flow problems, with confining boundaries of different curvatures. We have found that the modified MRT scheme is better suited for suspension flow in curved confining walls, while the TRT scheme is better for suspension flow confined between planar walls. With both schemes we have investigated problems for confined suspension flows, namely 1) drag forces experienced by spheres flowing in confining flow channels of different cross sections, and 2) the lubrication force between a sedimenting sphere and the end cap of a confining cylindrical capillary. © 2010 Elsevier B.V. Source

Boezeman D.,Radboud University Nijmegen | Vink M.,Wageningen University | Leroy P.,Radboud University Nijmegen
Environmental Science and Policy | Year: 2013

Scholars stress the need to bring science and policy together for effective policy making. This paper highlights an interesting site of co-production: the second Dutch Delta Committee. Consisting of representatives of science, politics, policy and industry, this state committee advised the Dutch government on adapting to climate change in 2008. Although the committee went beyond common climate projections and advocated non-incremental policy recommendations, its report provoked little opposition. Subsequently, its recommendations shaped institutional reform and policy development in Dutch adaptive governance. Using the concept of boundary organisations, this paper opens up the black box of the advisory process to explain the Delta Committee's functioning. We conclude that the current understanding of the effectiveness of boundary organisations tends to focus on their internal organisation. The internal processing, shaped by the deliberate composition and organisation of the committee, was indeed important for the production of useful knowledge and management of multiple boundaries. However, this was paralleled by external practices of continued interaction with a range of political, departmental, scientific and public actors in which the Committee positioned the advise. While the former mainly enabled the production of a high quality advice, the latter quested for its acceptation and legitimacy. © 2013 Elsevier Ltd. Source

Speakman J.R.,CAS Institute of Genetics and Developmental Biology | Speakman J.R.,University of Aberdeen | Keijer J.,Wageningen University
Molecular Metabolism | Year: 2013

It has been argued that mice should be housed at 30°C to best mimic the thermal conditions experienced by humans, and that the current practice of housing mice at 20-22°C impairs the suitability of mice as a model for human physiology and disease. In the current paper we challenge this notion. First, we show that humans routinely occupy environments about 3°C below their lower critical temperature (Tlc), which when lightly clothed is about 23°C. Second, we review the data for the Tlc of mice. Mouse Tlc is dependent on body weight and about 26-28°C for adult mice weighing >25g. The equivalent temperature to that normally experienced by humans for most single housed adult mice is therefore 23-25°C. Group housing or providing the mice with bedding and nesting material might lower this to about 20-22°C, close to current standard practice. © 2013. Source

Mol A.P.J.,Wageningen University
Global Environmental Change | Year: 2011

China's unprecedented economic growth path over the last two decades has been paralleled by an exponential growth in the consumption of natural resources and in pollution. Initially, China mainly exploited domestic resources to fuel its rapid industrial development. But over the last decade, increasing shares of China's natural resources consumption and environmental impacts relate to peripheral regions, including sub-Saharan Africa. China's environmental impacts in peripheral regions seem in line with World-Systems Theory predictions for ascending world powers. This paper assesses the extent to which the World-Systems Theory idea of 'environmentally unequal exchange' between ascending world powers and peripheral economies reflects current behaviour of Chinese governmental authorities and companies in sub-Saharan Africa. It concludes that the theory only partly does so. Behaviour of Chinese governmental authorities and firms is conditioned and guided by environmental norms, as well. World-Systems Theory has to make conceptual space for such new environmental behaviour of ascending world powers, to understand the contemporary and future world-systems. At the same time, China has a long way to go before becoming the 'green' exemplar for the world to follow. © 2011 Elsevier Ltd. Source

Raaijmakers J.M.,Wageningen University | Mazzola M.,U.S. Department of Agriculture
Annual Review of Phytopathology | Year: 2012

Soil-and plant-associated environments harbor numerous bacteria that produce antibiotic metabolites with specific or broad-spectrum activities against coexisting microorganisms. The function and ecological importance of antibiotics have long been assumed to yield a survival advantage to the producing bacteria in the highly competitive but resource-limited soil environments through direct pression. Although specific antibiotics may enhance producer persistence when challenged by competitors or predators in soil habitats, at subinhibitory concentrations antibiotics exhibit a diversity of other roles in the life history of the producing bacteria. Many processes modulated by antibiotics may be inherently critical to the producing bacterium, such as the acquisition of substrates or initiation of developmental changes that will ensure survival under stressful conditions. Antibiotics may also have roles in more complex interactions, including in virulence on host plants or in shaping the outcomes of multitrophic interactions. The innate functions of antibiotics to producing bacteria in their native ecosystem are just beginning to emerge, but current knowledge already reveals a breadth of activities well beyond the historical perspective of antibiotics as weaponry in microbial conflicts. © 2012 by Annual Reviews. All rights reserved. Source

Leys D.,University of Manchester | Adrian L.,Helmholtz Center for Environmental Research | Smidt H.,Wageningen University
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2013

Bacterial respiration has taken advantage of almost every redox couple present in the environment. The reduction of organohalide compounds to release the reduced halide ion drives energy production in organohalide respiring bacteria. This process is centred around the reductive dehalogenases, an iron-sulfur and corrinoid containing family of enzymes. These enzymes, transcriptional regulators and the bacteria themselves have potential to contribute to future bioremediation solutions that address the pollution of the environment by halogenated organic compounds. © 2013 The Author(s) Published by the Royal Society. All rights reserved. Source

Verhulst E.C.,Wageningen University | Van de zande L.,University of Groningen
Briefings in Functional Genomics | Year: 2015

In recent years, our knowledge of the conserved master-switch gene doublesex (dsx) and its function in regulating the development of dimorphic traits in insects has deepened considerably. Here, a comprehensive overview is given on the properties of the male- and female-specific dsx transcripts yielding DSXF and DSXM proteins in Drosophila melanogaster, and the many downstream targets that they regulate. As insects have cell-autonomous sex determination, it was assumed that dsx would be expressed in every somatic cell, but recent research showed that dsx is expressed only when a cell is required to show its sexual identity through function or morphology. This spatiotemporal regulation of dsx expression has not only been established in D. melanogaster but in all insect species studied. Gradually, it has been appreciated that dsx could no longer be viewed as the master-switch gene orchestrating sexual development and behaviour in each cell, but instead should be viewed as the interpreter for the sexual identity of the cell, expressing this identity only on request, making dsx the central nexus of insect sex determination. © The Author 2015. Published by Oxford University Press. Source

Karlsson-Vinkhuyzen S.I.,Wageningen University | McGee J.,University of Newcastle
Global Environmental Politics | Year: 2013

Studies grounded in regime theory have examined the effectiveness of "minilateral" climate change forums that have emerged outside of the UN climate process. However, there are no detailed studies of the legitimacy of these forums or of the impacts of their legitimacy on effectiveness and governance potential. Adopting the lens of legitimacy, we analyze the reasons for the formation of minilateral climate change forums and their recent role in global climate governance. We use Karlsson-Vinkhuyzen and Vihma's analytical framework for international institutions to examine three minilateral climate forums: the Asia-Pacific Partnership, the Major Economies Meetings, and the G8 climate process. These forums have significant deficits in their source-based, process-based, and outcome-based legitimacy, particularly when compared to the United Nations Framework Convention on Climate Change. If assessed purely on grounds of effectiveness, the minilateral forums might be easily dismissed as peripheral to the UN climate process. However, they play important roles by providing sites for powerful countries to shape the assumptions and expectations of global climate governance. Thus, the observed institutional fragmentation allows key states to use minilateral forums to shape the architecture of global climate governance. © 2013 by the Massachusetts Institute of Technology. Source

Hellegers P.,Wageningen University | Davidson B.,University of Melbourne
Agricultural Water Management | Year: 2010

In this paper the residual method is used to determine the disaggregated economic value of irrigation water used in agriculture across crops, zones and seasons. This method relies on the belief that the value of a good (its price by its quantity) is equal to the summation of the quantity of each input multiplied by its average value. By applying this method to the Musi sub-basin; a subdivision of the Krishna basin in India, it was found that the value of irrigation water use is not equated across the crops, zones and seasons. The reasons why there is no sinlge value of irrigation water use are suggested. As farmers do not have perfect knowledge, do not all possess the same resource base, plant different crops for a variety of reasons (some for a financial return on land instead of water and others for sustenance), possess different crop rotation practices and are possibly riks adverse, they all value water differently. However, the results need to be interpreted with care as the crop with the lowest return to water is probably not the one to be sacrificed if water is restricted, since farmers plant crops for a variety of reasons (and sometimes not for the highest return to water that they can achieve). © 2010 Elsevier B.V. All rights reserved. Source

Kromhout D.,Wageningen University
Current Opinion in Lipidology | Year: 2012

PURPOSE OF REVIEW: The fish fatty acids eicosapentenoic acid (EPA) and docosahexenoic acid (DHA) may be protective against fatal coronary heart disease (CHD) and sudden cardiac death. This review summarizes the recent findings of prospective cohort studies and randomized controlled trials. RECENT FINDINGS: A recently published meta-analysis of 17 prospective cohort studies showed that eating fish once a week compared to eating less fish was associated with a 16% lower risk of fatal CHD. Epidemiologic studies with cardiac arrest or sudden cardiac death as endpoint observed also an inverse relation with fish consumption. In contrast, a recently published meta-analysis of 14 randomized, double-blind, placebo-controlled trials in cardiovascular patients did not show a protective effect of an additional amount of EPA-DHA on fatal CHD and sudden cardiac death. Subgroup analyses suggested that this could be because of a low absolute risk as a consequence of the state-of-the-art drug treatment. SUMMARY: Eating fatty fish once or lean fish twice a week is recommended for both primary and secondary prevention of CHD. A definite statement cannot be made about the dosage of EPA-DHA required for secondary prevention of CHD. © 2012 Wolters Kluwer Health|Lippincott Williams & Wilkins. Source

Croce R.,University of Groningen | Van Amerongen H.,Wageningen University
Journal of Photochemistry and Photobiology B: Biology | Year: 2011

Photosystem II (PSII) is responsible for the water oxidation in photosynthesis and it consists of many proteins and pigment-protein complexes in a variable composition, depending on environmental conditions. Sunlight-induced charge separation lies at the basis of the photochemical reactions and it occurs in the reaction center (RC). The RC is located in the PSII core which also contains light-harvesting complexes CP43 and CP47. The PSII core of plants is surrounded by external light-harvesting complexes (lhcs) forming supercomplexes, which together with additional external lhcs, are located in the thylakoid membrane where they perform their functions. In this paper we provide an overview of the available information on the structure and organization of pigment-protein complexes in PSII and relate this to experimental and theoretical results on excitation energy transfer (EET) and charge separation (CS). This is done for different subcomplexes, supercomplexes, PSII membranes and thylakoid membranes. Differences in experimental and theoretical results are discussed and the question is addressed how results and models for individual complexes relate to the results on larger systems. It is shown that it is still very difficult to combine all available results into one comprehensive picture. © 2011 Elsevier B.V. All rights reserved. Source

Beyene T.,University of Washington | Lettenmaier D.P.,University of Washington | Kabat P.,Wageningen University
Climatic Change | Year: 2010

We assess the potential impacts of climate change on the hydrology and water resources of the Nile River basin using a macroscale hydrology model. Model inputs are bias corrected and spatially downscaled 21st Century simulations from 11 General Circulation Models (GCMs) and two global emissions scenarios (A2 and B1) archived from the 2007 IPCC Fourth Assessment Report (AR4). While all GCMs agree with respect to the direction of 21st Century temperature changes, there is considerable variability in the magnitude, direction, and seasonality of projected precipitation changes. Our simulations show that, averaged over all 11 GCMs, the Nile River is expected to experience increase in streamflow early in the study period (2010-2039), due to generally increased precipitation. Streamflow is expected to decline during mid- (2040-2069) and late (2070-2099) century as a result of both precipitation declines and increased evaporative demand. The predicted multimodel average streamflow at High Aswan Dam (HAD) as a percentage of historical (1950-1999) annual average are 111 (114), 92 (93) and 84 (87) for A2 (B1) global emissions scenarios. Implications of these streamflow changes on the water resources of the Nile River basin were analyzed by quantifying the annual hydropower production and irrigation water release at HAD. The long-term HAD release for irrigation increases early in the century to 106 (109)% of historical, and then decreases to 87 (89) and 86 (84)% of historical in Periods II and III, respectively, for the A2 (B1) global emissions scenarios. Egypt's hydropower production from HAD will be above the mean annual average historical value of about 10,000 GWH for the early part of 21st century, and thereafter will generally follow the streamflow trend, however with large variability among GCMs. Agricultural water supplies will be negatively impacted, especially in the second half of the century. © 2009 Springer Science+Business Media B.V. Source

Sheldon R.A.,Technical University of Delft | Sanders J.P.M.,Wageningen University
Catalysis Today | Year: 2014

The development of a set of sustainability metrics for quickly evaluating the production of commoditychemicals from renewable biomass is described. The method is based on four criteria: material and energyefficiency, land use and process economics. The method will be used for comparing the sustainability ofthe production of seven commodity chemicals lactic acid, 1-butanol, propylene glycol, succinic acid,acrylonitrile, isoprene and methionine from fossil feedstocks (crude oil or natural gas) versus renewablebiomass. © 2014 Elsevier B.V. All rights reserved. Source

Peters K.,University of Swansea | Richards P.,Wageningen University
Journal of Agrarian Change | Year: 2011

This paper assesses the extent to which customary governance in Sierra Leone can be held responsible for an increasingly unstable two-class agrarian society. A case is made for regarding the civil war (1991-2002) as being an eruption of long-term, entrenched agrarian tensions exacerbated by chiefly rule. Evidence is presented to suggest that the main rebel movement embodied in its plans to reorganize agricultural production some grasp of these longer-term agrarian problems. Postwar attempts to implement co-operative farming and mining are then described. The failure of these schemes is linked to the reinstitution of customary land law and local patronage systems. Current struggles over land now involve international capital. Deep agrarian reforms will be required as the price of keeping international capital engaged in the Sierra Leone countryside. © 2011 Blackwell Publishing Ltd. Source

Weijers D.,Wageningen University | Wagner D.,University of Pennsylvania
Annual Review of Plant Biology | Year: 2016

Auxin is arguably the most important signaling molecule in plants, and the last few decades have seen remarkable breakthroughs in understanding its production, transport, and perception. Recent investigations have focused on transcriptional responses to auxin, providing novel insight into the functions of the domains of key transcription regulators in responses to the hormonal cue and prominently implicating chromatin regulation in these responses. In addition, studies are beginning to identify direct targets of the auxin-responsive transcription factors that underlie auxin modulation of development. Mechanisms to tune the response to different auxin levels are emerging, as are first insights into how this single hormone can trigger diverse responses. Key unanswered questions center on the mechanism for auxin-directed transcriptional repression and the identity of additional determinants of auxin response specificity. Much of what has been learned in model plants holds true in other species, including the earliest land plants. Copyright © 2016 by Annual Reviews. All rights reserved. Source

Harmsen J.,Wageningen University | Naidu R.,University of South Australia
Journal of Hazardous Materials | Year: 2013

Bioavailability can form the basis for describing potential risks that contaminants pose to the environment and human health, and for determining remedial options to reduce risks of contaminant dispersal and toxicity. In assessments of polluted sites, methods to measure bioavailability can lead to a realistic appraisal of the potential risks from exposure to contaminants. For remediation purposes the application of the principles of bioavailability can result in practices that reduce bioavailability and consequently the risk of contaminants. Moreover the costs of remediation can be reduced. Examples from projects with organic contaminants (PAHs, pesticides and PFOS) and heavy metals in The Netherlands, Mali, Mauretania, Australia and Taiwan are presented. It is shown that using bioavailability principles in risk-based approaches is an attractive option in terms of both cost and in situ management of contaminated sites. Regulatory and public acceptance is, however, still the Achilles heel of these new remediation strategies. © 2013 Elsevier B.V. Source

Daetwyler H.D.,Australian Department of Primary Industries and Fisheries | Calus M.P.L.,Wageningen University | Pong-Wong R.,Roslin Institute | de los Campos G.,University of Alabama at Birmingham | And 2 more authors.
Genetics | Year: 2013

The genomic prediction of phenotypes and breeding values in animals and plants has developed rapidly into its own research field. Results of genomic prediction studies are often difficult to compare because data simulation varies, real or simulated data are not fully described, and not all relevant results are reported. In addition, some new methods have been compared only in limited genetic architectures, leading to potentially misleading conclusions. In this article we review simulation procedures, discuss validation and reporting of results, and apply benchmark procedures for a variety of genomic prediction methods in simulated and real example data. Plant and animal breeding programs are being transformed by the use of genomic data, which are becoming widely available and cost-effective to predict genetic merit. A large number of genomic prediction studies have been published using both simulated and real data. The relative novelty of this area of research has made the development of scientific conventions difficult with regard to description of the real data, simulation of genomes, validation and reporting of results, and forward in time methods. In this review article we discuss the generation of simulated genotype and phenotype data, using approaches such as the coalescent and forward in time simulation. We outline ways to validate simulated data and genomic prediction results, including cross-validation. The accuracy and bias of genomic prediction are highlighted as performance indicators that should be reported. We suggest that a measure of relatedness between the reference and validation individuals be reported, as its impact on the accuracy of genomic prediction is substantial. A large number of methods were compared in example simulated and real (pine and wheat) data sets, all of which are publicly available. In our limited simulations, most methods performed similarly in traits with a large number of quantitative trait loci (QTL), whereas in traits with fewer QTL variable selection did have some advantages. In the real data sets examined here all methods had very similar accuracies. We conclude that no single method can serve as a benchmark for genomic prediction. We recommend comparing accuracy and bias of new methods to results from genomic best linear prediction and a variable selection approach (e.g., BayesB), because, together, these methods are appropriate for a range of genetic architectures. An accompanying article in this issue provides a comprehensive review of genomic prediction methods and discusses a selection of topics related to application of genomic prediction in plants and animals. © 2013 by the Genetics Society of America. Source

de Jong R.,University of Zurich | Schaepman M.E.,University of Zurich | Furrer R.,University of Zurich | de Bruin S.,Wageningen University | Verburg P.H.,VU University Amsterdam
Global Change Biology | Year: 2013

Vegetation forms a main component of the terrestrial biosphere and plays a crucial role in land-cover and climate-related studies. Activity of vegetation systems is commonly quantified using remotely sensed vegetation indices (VI). Extensive reports on temporal trends over the past decades in time series of such indices can be found in literature. However, little remains known about the processes underlying these changes at large spatial scales. In this study, we aimed at quantifying the spatial relationship between changes in potential climatic growth constraints (i.e. temperature, precipitation and incident solar radiation) and changes in vegetation activity (1982-2008). We demonstrate an additive spatial model with 0.5° resolution, consisting of a regression component representing climate-associated effects and a spatially correlated field representing the combined influence of other factors, including land-use change. Little over 50% of the spatial variance could be attributed to changes in climatologies; conspicuously, many greening trends and browning hotspots in Argentina and Australia. The nonassociated model component may contain large-scale human interventions, feedback mechanisms or natural effects, which were not captured by the climatologies. Browning hotspots in this component were especially found in subequatorial Africa. On the scale of land-cover types, strongest relationships between climatologies and vegetation activity were found in forests, including indications for browning under warming conditions (analogous to the divergence issue discussed in dendroclimatology). © 2013 Blackwell Publishing Ltd. Source

Spiertz H.,Wageningen University
Sustainability (Switzerland) | Year: 2013

The demand for food, feed, and feedstocks for bioenergy and biofactory plants will increase proportionally due to population growth, prosperity, and bioeconomic growth. Securing food supply and meeting demand for biomass will involve many biological and agro-ecological aspects such as genetic plant improvement, sustainable land use, water-saving irrigation, and integrated nutrient management as well as control of pests, diseases and weeds. It will be necessary to raise biomass production and economic yield per unit of land-not only under optimum growing conditions, but even more under conditions constrained by climate, water availability, and soil quality. Most of the advanced agronomic research by national and international research institutes is dedicated to the major food crops: maize, rice, wheat, and potato. However, research on crops grown as feedstock, for bio-energy and industrial use under conditions with biophysical constraints, is lagging behind. Global and regional assessments of the potential for growing crops are mostly based on model and explorative studies under optimum conditions, or with either water or nitrogen deficiencies. More investments in combined experimental and modeling research are needed to develop and evaluate new crops and cropping systems under a wide range of agro-ecological conditions. An integral assessment of the biophysical production capacity and the impact on resource use, biodiversity and socio-economic factors should be carried out before launching large-scale crop production systems in marginal environments. © 2013 by the authors. Source

Giessen L.,University of Gottingen | Giessen L.,Wageningen University
International Forestry Review | Year: 2013

The objectives of this review article are, firstly, to provide an overview of the literature on the main characteristics of what is referred to as the international forest regime and secondly, based on this, to review explanations for fragmentation as its core characteristic. A third aim of the article is to propose fields for future policy-oriented research on global forest governance, the international forest regime and its fragmentation. The article discusses different strands of literature and academic views on the existence and main characteristics of an international forest regime. It regards the recent notion of an international forest regime complex to be a fruitful topic for future research proposals and finds that fragmentation is its analytical core characteristic. In addition, the article reviews partial explanations for the great relevance of fragmentation in the case of the forest regime complex. It discriminates between domestic factors and causes as opposed to those resulting from the international system. Based on the review, the article suggests, lastly, fields for future research on global forest governance, the international forest regime complex and its fragmentation. Source

de Jong B.G.,Wageningen University
PloS one | Year: 2013

Specificity, antibody isotype distribution and levels of natural antibodies (NAb) may be potential informative parameters for immune mediated natural disease resistance, immune modulation, and maintenance of physiological homeostasis. A large proportion of mammalian NAb have affinity for or are directed against self-antigens; so called natural auto antibodies (N(A)Ab). In the present study we showed the presence and typed levels and isotypes (total immunoglobulins, IgG and IgM) of N(A)Ab in plasma binding the 'auto-antigen' complex chicken liver cell lysate (CLL) of one-year old chickens from different genotype and phenotype backgrounds by ELISA and quantitative Western blotting. Higher levels of N(A)Ab binding CLL were found in plasma from chickens genetically selected for high specific antibody responses. In all birds, extensive staining patterns of plasma antibodies binding CLL were found for all isotypes, with IgG binding the highest number of CLL antigens and also showing the highest variation in staining patterns between individuals. Patterns of IgM antibodies binding CLL appeared to be more similar in all lines. Significant differences of binding patterns of N(A)Ab (antigen fragments of CLL and staining intensity) were detected between the different chicken lines, and lines could be clustered on the basis of their auto-antibody profile. In addition, also individual differences within lines were found. The present results indicate that analysis of the levels and the N(A)Ab repertoire of poultry like in mammals could provide a new way of distinguishing differences of immune competence and immune maturation between individuals, and could provide tools to select birds for health traits, or optimize hygiene and husbandry procedures. Source

Kistenkas F.H.,Wageningen University
Journal for European Environmental and Planning Law | Year: 2013

European nature conservation law with its habitats assessment as demanded by Article 6 of the 1992 Habitats Directive is recently being regarded as rigid, rather static and not fully updated with modern sustainability and climate change demands. As a consequence nature conservation law is said to be not always capable to facilitate sustainable development. A balancing of both ecology and socio-economic interests rather than a singular ecological criteria assessment might give way to sustainable combinations of land use in or nearby nature reserves. While previous authors call for updating and restructuring the Habitats Directive, this paper argues that the EU legislative framework, consisting of European treaty law with its environmental law principles as well as the wording of Article 6 itself, already offers adequate opportunities to re-interpret the EU nature conservation directives within the context of sustainable land use, thus giving way to a less dogmatic approach entirely in line with modern sustainable development demands. © 2013 by Koninklijke Brill NV, Leiden. Source

Dijk W.,Wageningen University
Current Opinion in Lipidology | Year: 2016

PURPOSE OF REVIEW: The angiopoietin-like proteins (ANGPTLs) 3, 4 and 8 have emerged as key regulators of plasma lipid metabolism by serving as potent inhibitors of the enzyme lipoprotein lipase (LPL). In this review, we provide an integrated picture of the role of ANGPTL3, ANGPTL4 and ANGPTL8 in lipid metabolism by focusing on their impact on LPL activity and plasma triglyceride clearance during physiological conditions such as fasting, refeeding, exercise and cold exposure. RECENT FINDINGS: Upon refeeding, circulating ANGPTL3 and ANGPTL8 promote the replenishment of white adipose tissue depots by specifically inhibiting LPL activity in oxidative tissues. During exercise and cold exposure, ANGPTL4 represses local LPL activity to assure that plasma triglycerides are specifically shuttled to exercising muscle and brown adipose tissue, respectively. Overall, ANGPTL4 is the central component of a fatty acid-driven feedback mechanism that regulates plasma triglyceride hydrolysis and subsequent tissue fatty acid uptake in response to changes in lipid availability and cellular fuel demand. SUMMARY: ANGPTL3, ANGPTL4 and ANGPTL8 together ensure that triglycerides from triglyceride-rich lipoproteins are adequately distributed during different physiological conditions. The impact of the ANGPTLs on plasma lipid levels has led to scrutiny of ANGPTLs as therapeutic targets for dyslipidemia. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved. Source

Vij S.,Wageningen University | Narain V.,Management Development Institute MDI
Land Use Policy | Year: 2016

This paper describes how urbanization processes and urban expansion intersect with social and power relations to reduce the access of periurban communities to common property resources (CPRs). Unequal power structures mean that certain groups are deprived of access to village CPRs. Processes of urban expansion further reduce access to CPRs, as the latter are acquired to support urban expansion. Though rural-urban transformations are characterized by the emergence of new sources of irrigation such as wastewater, not all are able to benefit from them. The acquisition of common property grazing lands to support the drinking water needs of the city affects the livelihood of livestock dependent population, that shift to casual labor. This also translates into a shift from grazing, the domain of men in the household, to stall-feeding, the domain of women, and thereby creating additional responsibilities for women in natural resource collection. The demise of CPRs such as village ponds with the increased pressure on groundwater resources increase the drudgery of women and marginalized groups in accessing water. © 2015 Elsevier Ltd. Source

Brakefield P.M.,Leiden University | Brakefield P.M.,University of Sheffield | De Jong P.W.,Wageningen University
Heredity | Year: 2011

A cline in the frequency of melanic morphs of the two-spot ladybird, Adalia bipunctata, was first surveyed in 1980 along a transect extending inland from the coast in the Netherlands. At that time, the frequency of melanics increased over some 40 km from 10% near the coast to nearly 60% inland. Additional surveys made in 1991 and 1995 demonstrated some progressive change in cline shape. New samples from 1998 and 2004 confirm these dynamics, and show that over a period of about 50 generations for the beetle, the cline had decayed rapidly to yield rather uniform frequencies of melanic morphs at around 20% along the whole transect by 2004. Climate data and evidence for thermal melanism in this species support our contention that these dynamics reflect a dramatic example of a rapid genetic response within populations to climate change and local selection. © 2011 Macmillan Publishers Limited All rights reserved. Source

Elbers A.R.W.,Wageningen University
Medical and Veterinary Entomology | Year: 2016

The light trap is the tool of choice for conducting large-scale Culicoides (Diptera: Ceratopogonidae) vector surveillance programmes. Its efficacy is in doubt, however. To assess this, hourly changes in Culicoides activity over the 24-h diel were determined comparatively by way of light trapping and aerial sweeping, and correlated against light intensity. In the Netherlands, sweeping around cattle at pasture revealed that, in early summer, Culicoides are active throughout the diel, and that their abundance peaks during the crepuscular period and falls to a low during the brightest hours of the day. By contrast, the light trap was able to accumulate Culicoides only at night (i.e. after illuminance levels had dropped to 0 lux and midge activity had begun to decline). Although Culicoides chiopterus and species of the Culicoides obsoletus complex were similarly abundant around livestock, they differed critically in their hours of peak activity, being largely diurnal and nocturnal, respectively. This polarity helps to explain why, routinely, the C. obsoletus complex dominates light trap collections and C. chiopterus does not. Inability to accumulate Culicoides at light intensity levels above 0 lux means that, at ever-higher latitudes, particularly beyond 45° N, the progressive northward lengthening of the twilight period will have an increasingly adverse impact upon the efficacy of the light trap as a vector surveillance tool. © 2016 The Royal Entomological Society. Source

Lyklema J.,Wageningen University
Colloids and Surfaces A: Physicochemical and Engineering Aspects | Year: 2011

Surface charges and electrokinetic charges are very different double layer characteristics. It is mandatory to discriminate between them. If for a given system both of them are known, much relevant double layer information becomes accessible. The present state of this juxtapositioning is reviewed on the basis of real physical measurements with well-defined systems. The added information includes counterion adsorption and stagnant layer conduction. Special attention will be paid to overcharging, including an option for distinguishing between interpretation in terms of specific adsorption and ion correlations. © 2010 Elsevier B.V. Source

Waha K.,Potsdam Institute for Climate Impact Research | Van Bussel L.G.J.,Wageningen University | Van Bussel L.G.J.,Netherlands Environmental Assessment Agency | Muller C.,Potsdam Institute for Climate Impact Research | Bondeau A.,Potsdam Institute for Climate Impact Research
Global Ecology and Biogeography | Year: 2012

Aim To simulate the sowing dates of 11 major annual crops at the global scale at high spatial resolution, based on climatic conditions and crop-specific temperature requirements. Location Global. Methods Sowing dates under rainfed conditions are simulated deterministically based on a set of rules depending on crop- and climate-specific characteristics. We assume that farmers base their timing of sowing on experiences with past precipitation and temperature conditions, with the intra-annual variability being especially important. The start of the growing period is assumed to be dependent either on the onset of the wet season or on the exceeding of a crop-specific temperature threshold for emergence. To validate our methodology, a global data set of observed monthly growing periods (MIRCA2000) is used. Results We show simulated sowing dates for 11 major field crops world-wide and give rules for determining their sowing dates in a specific climatic region. For all simulated crops, except for rapeseed and cassava, in at least 50% of the grid cells and on at least 60% of the cultivated area, the difference between simulated and observed sowing dates is less than 1 month. Deviations of more than 5 months occur in regions characterized by multiple-cropping systems, in tropical regions which, despite seasonality, have favourable conditions throughout the year, and in countries with large climatic gradients. Main conclusions Sowing dates under rainfed conditions for various annual crops can be satisfactorily estimated from climatic conditions for large parts of the earth. Our methodology is globally applicable, and therefore suitable for simulating sowing dates as input for crop growth models applied at the global scale and taking climate change into account. © 2011 Blackwell Publishing Ltd. Source

Klerkx L.,Wageningen University | Proctor A.,Northumbria University
Land Use Policy | Year: 2013

The growing multifunctionality in agriculture, combined with privatisation of previously public agricultural extension services, has resulted in a pluralistic land management advisory system. Despite benefits in terms of increased client orientation and greater advisor diversity, it is argued that these changes have resulted in the fragmentation of the land management advisory system and a reduction of interaction within the advisory system and between the advisory system and science. Hence, concerns have been voiced as regards the capacity of the advisory system to be able to incorporate new knowledge, resulting in a growing interest in how advisors obtain and construct the knowledge necessary for offering adequate advisory services to their clients. In this article we explore how advisors within the English land management advisory system (land agents, applied ecologists and veterinarians) develop and optimise their knowledge by engaging in different kinds of networks (centralised, distributed and decentralised), each of which employs a different type of social capital. Key findings suggest that to obtain the knowledge needed to solve complex queries of clients, advisors use distributed networks and draw upon informal 'communities of practice' within their own advisory profession characterised by bonding social capital, but also draw upon broader 'networks of practice' involving multiple advisors from different advisory professions, which rely on bridging social capital. The employment of decentralised networks which rely on linking social capital, to solve complex queries or develop new services, for example through contacts with scientific institutes, appears to be less developed, despite brokering activities of the professional associations. Whereas fragmentation and disconnect due to competition and epistemological differences do play a role; they do not appear to prevent overall knowledge exchange among advisors within and across different professions. Assumptions of a collapse of interaction within the land management advisory system are not supported by the evidence, as there appears to be much bonding and bridging social capital. However, to optimise interactions between professions, and between advisors and the science system, either informal brokers or formal brokers in the form of professional associations or other organisations could play a bigger role. © 2012 Elsevier Ltd. Source

Hilhorst H.W.M.,Wageningen University
Methods in Molecular Biology | Year: 2011

Seeds are very attractive and convenient for molecular genetic studies that challenge principal biological phenomena related to the initiation and suppression of growth (e.g., germination and dormancy, respectively). The number of reports in this field is rapidly expanding. Seed dormancy is a widely misinterpreted biological attribute. One of the main reasons is the general neglect of reliable dormancy assays; often, the sole criterion of current dormancy assays is the total germination of a seed population after a defined period of time. This is a very insensitive and inaccurate method, particularly when comparing dormancy levels of seeds from different genotypes, seeds subjected to different treatments, or seeds originating from different environments. Other seed parameters are far more useful. Furthermore, before undertaking comprehensive molecular and biochemical studies to elucidate the underlying mechanisms of dormancy of a given species, it is pivotal to determine the general types or categories of dormancy that are imposed and whether these are influenced by the external environment. Research strategies should be adjusted to this. In order to distinguish dead from dormant seeds, a viability test should be developed. This chapter addresses in a very general way these pitfalls in dormancy research with a focus on current plant model systems in molecular genetics, such as Arabidopsis thaliana and Medicago truncatula. © 2011 Springer Science+Business Media, LLC. Source

Thebault E.,Imperial College London | Thebault E.,Wageningen University | Fontaine C.,Imperial College London | Fontaine C.,CNRS Science Conservation Center
Science | Year: 2010

Research on the relationship between the architecture of ecological networks and community stability has mainly focused on one type of interaction at a time, making difficult any comparison between different network types. We used a theoretical approach to show that the network architecture favoring stability fundamentally differs between trophic and mutualistic networks. A highly connected and nested architecture promotes community stability in mutualistic networks, whereas the stability of trophic networks is enhanced in compartmented and weakly connected architectures. These theoretical predictions are supported by a meta-analysis on the architecture of a large series of real pollination (mutualistic) and herbivory (trophic) networks. We conclude that strong variations in the stability of architectural patterns constrain ecological networks toward different architectures, depending on the type of interaction. Source

Kuiper H.A.,Wageningen University | Davies H.V.,Scottish Crop Research Institute
Food Control | Year: 2010

This paper describes the current EU regulatory framework for risk analysis of genetically modified (GM) crop cultivation and market introduction of derived food/feed. Furthermore the risk assessment strategies for GM crops and derived food/feed as designed by the European Food Safety Authority (EFSA) are described on which international agreement exists. Existing flaws in the EU regulatory framework for GMOs have been identified and proposals are put forward to improve current risk analysis procedures for GMOs by taking the SAFE FOODS Risk Analysis Framework into account. The SAFE FOODS framework describes an iterative decision-making process with four distinct stages i.e. framing, risk-benefit assessment, evaluation, and risk management which includes decision-making, and implementation, and a final review stage. Three major changes compared to current risk analyses practices are proposed, i.e. (i) the addition of a formal framing stage, during which problem formulation and the objectives of the risk analysis are established, (ii) enlargement of the scope of the risk assessment, by including the assessment of potential benefits, and an impact analysis of social and economic aspects, and (iii) addition of a formal evaluation stage, in order to weigh risks, costs and benefits and their distribution. Furthermore a broader participation of certain entities, organisations and individual citizens in specific segments of the risk analysis process, in particular in the framing and evaluation stage, is proposed. The proposed changes in current risk analyses practises may contribute to restore consumer confidence in risk analysis process of GMOs in the EU. © 2010 Elsevier Ltd. Source

Kwadijk C.J.A.F.,Institute for Marine Resources and Ecosystem Studies IMARES | Korytar P.,Institute for Marine Resources and Ecosystem Studies IMARES | Koelmans A.A.,Institute for Marine Resources and Ecosystem Studies IMARES | Koelmans A.A.,Wageningen University
Environmental Science and Technology | Year: 2010

The distribution of 15 perfluorinated compounds (PFCs) among eel (Anguilla anguilla), sediment, and water was investigated for 21 locations in The Netherlands. Furthermore, for perfluorooctanesulfonate (PFOS), a 30 year time series was measured for three locations using historical eel samples. These historical samples revealed concentrations increasing by a factor of 2-4 until the mid-1990s, followed by a return to the initial levels. In the samples described here, PFOS dominated aqueous concentrations, ranging from 4.7 to 32 ng/L in water, from 0.5 to 8.7 ng/g in sediment, and from 7 to 58 ng/g in eel filet. Field-based sediment water distribution coefficients (KD) were calculated and corrected for organic carbon content (KOC), which reduced variability among samples. Log KOC ranges were 2.6-3.7 for the C7-C9 carboxylic acids and 2.2-3.2 for the C4-C8 sulfonates. Bioaccumulation factors (log BAFs) for eel ranged from 1.09-3.26 for the C7-C9 carboxylic acids to 1.4-3.3 for the C4-C8 sulfonates. Perfluoroalkyl chain length correlated well with both sorption and bioaccumulation factors. Magnitudes and trends in KD or BAF appeared to agree well with previously published laboratory data. Results imply that PFCs are mainly present in water, which is important for PFC fate modeling and risk assessment. © 2010 American Chemical Society. Source

Blacquiere T.,Wageningen University | Smagghe G.,Ghent University | Van Gestel C.A.M.,VU University Amsterdam | Mommaerts V.,Ghent University
Ecotoxicology | Year: 2012

Neonicotinoid insecticides are successfully applied to control pests in a variety of agricultural crops; however, they may not only affect pest insects but also non-target organisms such as pollinators. This review summarizes, for the first time, 15 years of research on the hazards of neonicotinoids to bees including honey bees, bumble bees and solitary bees. The focus of the paper is on three different key aspects determining the risks of neonicotinoid field concentrations for bee populations: (1) the environmental neonicotinoid residue levels in plants, bees and bee products in relation to pesticide application, (2) the reported side-effects with special attention for sublethal effects, and (3) the usefulness for the evaluation of neonicotinoids of an already existing risk assessment scheme for systemic compounds. Although environmental residue levels of neonicotinoids were found to be lower than acute/chronic toxicity levels, there is still a lack of reliable data as most analyses were conducted near the detection limit and for only few crops. Many laboratory studies described lethal and sublethal effects of neonicotinoids on the foraging behavior, and learning and memory abilities of bees, while no effects were observed in field studies at field-realistic dosages. The proposed risk assessment scheme for systemic compounds was shown to be applicable to assess the risk for side-effects of neonicotinoids as it considers the effect on different life stages and different levels of biological organization (organism versus colony). Future research studies should be conducted with field-realistic concentrations, relevant exposure and evaluation durations. Molecular markers may be used to improve risk assessment by a better understanding of the mode of action (interaction with receptors) of neonicotinoids in bees leading to the identification of environmentally safer compounds. © Springer Science+Business Media, LLC 2012. Source

Dicke M.,Wageningen University
Journal of the Indian Institute of Science | Year: 2015

Plants respond to arthropod herbivory with the induction of volatiles that attract predatory arthropods that attack the herbivores. These so-called herbivore-induced plant volatiles (HIPVs) appear to be important sources of information that mediate many interactions within a plant-arthropod community. Predators can use HIPVs to find a food source in a complex environment. Moreover, predator responses are modulated by starvation and specific dietary deficiencies. In addition, HIPVs can influence the behaviour and distribution of other community members such as parasitic plants, herbivores, and hyperparasitoids. The collective outcome of these interactions determines the effect of the HIPVs on plant fitness and this has fuelled a debate on whether HIPVs can be beneficial to plants. Interestingly, the origin of the research on HIPVs has been an investigation of how predatory mites exterminate populations of their prey, the herbivorous spider mites. The value of HIPVs for durable pest control is discussed. © Indian Institute of Science. Source

Dijkstra J.,Wageningen University
Animal : an international journal of animal bioscience | Year: 2013

Ruminant production contributes to emissions of nitrogen (N) to the environment, principally ammonia (NH3), nitrous oxide (N2O) and di-nitrogen (N2) to air, nitrate (NO3 -) to groundwater and particulate N to surface waters. Variation in dietary N intake will particularly affect excretion of urinary N, which is much more vulnerable to losses than is faecal N. Our objective is to review dietary effects on the level and form of N excreted in cattle urine, as well as its consequences for emissions of N2O. The quantity of N excreted in urine varies widely. Urinary N excretion, in particular that of urea N, is decreased upon reduction of dietary N intake or an increase in the supply of energy to the rumen microorganisms and to the host animal itself. Most of the N in urine (from 50% to well over 90%) is present in the form of urea. Other nitrogenous components include purine derivatives (PD), hippuric acid, creatine and creatinine. Excretion of PD is related to rumen microbial protein synthesis, and that of hippuric acid to dietary concentration of degradable phenolic acids. The N concentration of cattle urine ranges from 3 to 20 g/l. High-dietary mineral levels increase urine volume and lead to reduced urinary N concentration as well as reduced urea concentration in plasma and milk. In lactating dairy cattle, variation in urine volume affects the relationship between milk urea and urinary N excretion, which hampers the use of milk urea as an accurate indicator of urinary N excretion. Following its deposition in pastures or in animal houses, ubiquitous microorganisms in soil and waters transform urinary N components into ammonium (NH4 +), and thereafter into NO3 - and ultimately in N2 accompanied with the release of N2O. Urinary hippuric acid, creatine and creatinine decompose more slowly than urea. Hippuric acid may act as a natural inhibitor of N2O emissions, but inhibition conditions have not been defined properly yet. Environmental and soil conditions at the site of urine deposition or manure application strongly influence N2O release. Major dietary strategies to mitigating N2O emission from cattle operations include reducing dietary N content or increasing energy content, and increasing dietary mineral content to increase urine volume. For further reduction of N2O emission, an integrated animal nutrition and excreta management approach is required. Source

Ruigrok V.J.,Wageningen University
Nucleic acids research | Year: 2013

Proteins that recognize and bind specific sites in DNA are essential for regulation of numerous biological functions. Such proteins often require a negative supercoiled DNA topology to function correctly. In current research, short linear DNA is often used to study DNA-protein interactions. Although linear DNA can easily be modified, for capture on a surface, its relaxed topology does not accurately resemble the natural situation in which DNA is generally negatively supercoiled. Moreover, specific binding sequences are flanked by large stretches of non-target sequence in vivo. Here, we present a straightforward method for capturing negatively supercoiled plasmid DNA on a streptavidin surface. It relies on the formation of a temporary parallel triplex, using a triple helix forming oligonucleotide containing locked nucleic acid nucleotides. All materials required for this method are commercially available. Lac repressor binding to its operator was used as model system. Although the dissociation constants for both the linear and plasmid-based operator are in the range of 4 nM, the association and dissociation rates of Lac repressor binding to the plasmid-based operator are ~18 times slower than on a linear fragment. This difference underscores the importance of using a physiologically relevant DNA topology for studying DNA-protein interactions. Source

Selakovic S.,Wageningen University
Proceedings. Biological sciences / The Royal Society | Year: 2014

Infectious agents are part of food webs and ecosystems via the relationship with their host species that, in turn, interact with both hosts and non-hosts. Through these interactions, infectious agents influence food webs in terms of structure, functioning and stability. The present literature shows a broad range of impacts of infectious agents on food webs, and by cataloguing that range, we worked towards defining the various mechanisms and their specific effects. To explore the impact, a direct approach is to study changes in food-web properties with infectious agents as separate species in the web, acting as additional nodes, with links to their host species. An indirect approach concentrates not on adding new nodes and links, but on the ways that infectious agents affect the existing links across host and non-host nodes, by influencing the 'quality' of consumer-resource interaction as it depends on the epidemiological state host involved. Both approaches are natural from an ecological point of view, but the indirect approach may connect more straightforwardly to commonly used tools in infectious disease dynamics. Source

Cruz L.J.,Radboud University Nijmegen | Tacken P.J.,Radboud University Nijmegen | Fokkink R.,Wageningen University | Figdor C.G.,Radboud University Nijmegen
Biomaterials | Year: 2011

Targeted delivery of nanoparticles (NPs) carrying vaccine components to dendritic cells (DCs) is a promising strategy to initiate antigen-specific immune responses. Improving the interactions between nanoparticle-carried ligands and receptors on DCs is a major challenge. These NPs are generally coated with poly(ethylene glycol) (PEG), to shield non-specific interactions, and antibodies, to facilitate specific delivery to DC surface receptors. We have devised a strategy to covalently link PEG molecules of various chain length (Mw 2000-20000 g/moL) to poly(lactic-co-)glycolic acid (PLGA) NP vaccines. We coated these NPs with various antibodies recognizing the DC-specific receptor DC-SIGN to study the effects of shielding and antibody type on antibody-receptor interactions. Chemical attachment of PEG to the particle surface was followed by detailed zeta potential, DLS and NMR studies, and analyzed by analytical chemistry. Increasing the PEG chain length increased particle size and polydispersity index and reduced the intracellular degradation rate of encapsulated antigens. Binding and uptake of NPs by human DCs was affected by both PEG chain length and antibody type. NPs coated with PEG-3000 had the optimal chain length for antibody-receptor interactions and induction of antigen-specific T-cell responses. Interestingly, clear differences were observed upon targeting distinct epitopes of the same receptor. Binding and uptake of NPs carrying antibodies recognizing the carbohydrate recognition domain of DC-SIGN was enhanced when compared to those carrying antibodies recognizing the receptor's neck region. In conclusion, our data show that PEG chains cannot be extended beyond a certain length for shielding purposes without compromising the efficacy of targeted delivery. Thereby, the implications of our findings are not limited to the future design of nanovaccines specifically targeted to DC-SIGN, but apply to the general design of targeted nanocarriers. © 2011 Elsevier Ltd. Source

Scheres B.,Wageningen University
Development (Cambridge) | Year: 2013

In 1993, we published a paper in Development detailing the anatomical structure of the Arabidopsis root. The paper described how root growth was maintained by the precisely tuned activity of a small set of 'initials', which acted as the source of dividing and differentiating cells, and how these stem cell-like cells surrounded a few infrequently dividing cells. This work underpinned subsequent research on root developmental biology and sparked a detailed molecular analysis of how stem cell groups are positioned and maintained in plants. © 2013. Published by The Company of Biologists Ltd. Source

de Vos W.M.,Wageningen University | de Vos W.M.,University of Helsinki | De Vos E.A.J.,University of Amsterdam
Nutrition Reviews | Year: 2012

Recorded observations indicating an association between intestinal microbes and health are long-standing in terms of specific diseases, but emerging high-throughput technologies that characterize microbial communities in the intestinal tract are suggesting new roles for the supposedly normal microbiome. This review considers the nature of the evidence supporting a relationship between the microbiota and the predisposition to disease as associative, correlative, or causal. Altogether, indirect or associative support currently dominates the evidence base, which now suggests that the intestinal microbiome can be linked to a growing number of over 25 diseases or syndromes. While only a handful of cause-and-effect studies have been performed, this form of evidence is increasing. The results of such studies are expected to be useful in monitoring disease development, in providing a basis for personalized treatments, and in indicating future therapeutic avenues. © 2012 International Life Sciences Institute. Source

Verdegem M.C.J.,Wageningen University
Reviews in Aquaculture | Year: 2013

In aquaculture, nutrient loading is defined as the difference between nutrients supplied with fertilizers and feed and nutrients harvested in the form of finfish, crustaceans, molluscs and seaweeds. On average, the production of finfish and crustaceans results in a net nutrient loading, while for the production of molluscs and seaweeds the nutrient loading is negative. In marine and brackish water aquaculture, on a global scale, more nutrients are extracted than added to the environment. However, in freshwater, more nutrients are loaded than extracted. In 2008, the global aquaculture production of finfish and crustaceans resulted in an environmental loading of 1.7 million metric tonnes of nitrogen (N) and 0.46 million metric tonnes of phosphorus (P). This nitrogen loading represents 0.9% of the human input to the N-cycle and 0.4% of the global N-cycle. For phosphorus, the loading from finfish and crustacean aquaculture represents 2.3% of the global annual fertilizer supply. With cage aquaculture, nutrients are directly discharged to the environment. Mitigation measures should be shared equally between all polluters involved. For land-based aquaculture, the development of water re-use systems is still in its infancy. Although still a minor contributor to global aquaculture production, recirculation technology shows that control and mitigation of pollution from aquaculture is possible. A 15-20 year goal should be to have all inland aquaculture operations applying water re-use and purification technology and generating useful (waste) outputs in addition to standard aquaculture products. © 2013 Wiley Publishing Asia Pty Ltd. Source

van der Knaap M.,Wageningen University
Aquatic Ecosystem Health and Management | Year: 2013

Four decades after the initial export of Nile Perch from Lake Victoria, which reached an annual maximum harvest of 330,000 tons in 2000 (LVFO, 2009), Nile Perch resources are under pressure. With a form of co-management in place, it is not clear who is responsible for resources management. The fishers claim the Governments are responsible and the Governments say that the fish export industry is responsible. Results of six years of research led the Council of Ministers of the Lake Victoria Fisheries Organization in 2003 to endorse the recommendation to enforce drastic measures. When the measures came into force they were strictly adhered to, but with time, the authorities unwillingly relaxed them until draconian measures then had to be taken. Identical measures were adopted by the Council in 2009 and this resulted in the professional fish export associations rigidly maintaining one portion, while claiming that no scientific evidence existed for the other part. The co-management system making use of Beach Management Units (BMU) is well developed on Lake Victoria, but has only been partly introduced to the shores of Lake Tanganyika, where certain management structures have existed for many years. This article discusses how the state of the optimum fish stocks could be regenerated, but notes that other external factors may also play roles (including climate change). On Lake Tanganyika an industrial fishery was operational in the northern part of the lake from the mid-1970s to the mid-1990s, which gradually moved southwards with time and was outcompeted by the emerging artisanal fishery, whose effort is still increasing. Whilst riparian Governments subscribe to international action plans, messages have to be put across to the fishing communities about regeneration of lake ecosystems. © 2013 Copyright Taylor and Francis Group, LLC. Source

Rienks J.,Wageningen University | Rienks J.,University of Queensland | Dobson A.J.,University of Queensland | Mishra G.D.,University of Queensland
European Journal of Clinical Nutrition | Year: 2013

Background/objectives: To investigate the association between dietary patterns and prevalence and incidence 3 years later of depressive symptoms using data from the mid-aged cohort in the Australian Longitudinal Study on Women's Health. Subjects/methods: Participants (aged 50-55 years) completed a food frequency questionnaire in 2001. Depressive symptoms were measured in 2001 and 2004 using the validated 10-item Centre for Epidemiologic Studies Depression scale. Multiple logistic regression was used for cross-sectional analysis (8369 women) and longitudinal analysis (7588) to assess the associations between dietary patterns and prevalence of depressive symptoms, and then for longitudinal analysis (6060) on their associations with the incidence of depressive symptoms in 2004, while adjusting for sociodemographic and lifestyle factors. Results: Six dietary patterns were identified from factor analysis: cooked vegetables, fruit, Mediterranean style, meat and processed meat, dairy, and high fat and sugar. A higher consumption of the Mediterranean-style diet had a cross-sectional association with lower prevalence of depressive symptoms in 2001, adjusted odds ratio 0.82 (95% confidence interval 0.77-0.88); and longitudinally with lower incidence of depressive symptoms in 2004, adjusted odds ratio 0.83 (0.75-0.91). None of the associations found for other dietary patterns remained statistically significant after adjustment for confounders. A dose-response relationship was found cross-sectionally when women were grouped according to quintiles of Mediterranean-style diet (P-value for trend <0.001). Conclusions: Consumption of a 'Mediterranean-style' dietary pattern by mid-aged women may have a protective influence against the onset of depressive symptoms. These findings suggest that dietary patterns have a potential role in the prevention and management of depressive symptoms. © 2013 Macmillan Publishers Limited. Source

Cermak N.M.,Maastricht University | Res P.T.,Maastricht University | De Groot L.C.P.G.M.,Wageningen University | Saris W.H.M.,Maastricht University | Van Loon L.J.C.,Maastricht University
American Journal of Clinical Nutrition | Year: 2012

Background: Protein ingestion after a single bout of resistance-type exercise stimulates net muscle protein accretion during acute postexercise recovery. Consequently, it is generally accepted that protein supplementation is required to maximize the adaptive response of the skeletal muscle to prolonged resistance-type exercise training. However, there is much discrepancy in the literature regarding the proposed benefits of protein supplementation during prolonged resistance-type exercise training in younger and older populations. Objective: The objective of the study was to define the efficacy of protein supplementation to augment the adaptive response of the skeletal muscle to prolonged resistance-type exercise training in younger and older populations. Design: A systematic review of interventional evidence was performed through the use of a random-effects meta-analysis model. Data from the outcome variables fat-free mass (FFM), fat mass, type I and II muscle fiber cross-sectional area, and 1 repetition maximum (1-RM) leg press strength were collected from randomized controlled trials (RCTs) investigating the effect of dietary protein supplementation during prolonged (>6 wk) resistance-type exercise training. Results: Data were included from 22 RCTs that included 680 subjects. Protein supplementation showed a positive effect for FFM (weighted mean difference: 0.69 kg; 95% CI: 0.47, 0.91 kg; P < 0.00001) and 1-RM leg press strength (weighted mean difference: 13.5 kg; 95% CI: 6.4, 20.7 kg; P < 0.005) compared with a placebo after prolonged resistance-type exercise training in younger and older subjects. Conclusion: Protein supplementation increases muscle mass and strength gains during prolonged resistance-type exercise training in both younger and older subjects. © 2012 American Society for Nutrition. Source

Heidstra R.,Wageningen University | Sabatini S.,University of Rome La Sapienza
Nature Reviews Molecular Cell Biology | Year: 2014

The astonishingly long lives of plants and their regeneration capacity depend on the activity of plant stem cells. As in animals, stem cells reside in stem cell niches, which produce signals that regulate the balance between self-renewal and the generation of daughter cells that differentiate into new tissues. Plant stem cell niches are located within the meristems, which are organized structures that are responsible for most post-embryonic development. The continuous organ production that is characteristic of plant growth requires a robust regulatory network to keep the balance between pluripotent stem cells and differentiating progeny. Components of this network have now been elucidated and provide a unique opportunity for comparing strategies that were developed in the animal and plant kingdoms, which underlie the logic of stem cell behaviour. © 2014 Macmillan Publishers Limited. Source

Van Der Zanden E.H.,VU University Amsterdam | Verburg P.H.,VU University Amsterdam | Mucher C.A.,Wageningen University
Ecological Indicators | Year: 2013

Linear landscape elements, such as ditches, hedgerows, lines of trees and field margins, provide important habitats and ecosystem services and function as ecological infrastructure for species within agricultural landscapes. Spatial maps of the distribution of these elements are needed to better represent landscape structure within regional scale environmental assessments. We present wall-to-wall maps for green lines, ditches and grass margins for Europe, using spatial modelling of ground observations on linear features from the 2009 LUCAS (land use/cover area frame statistical survey) database. We compare different spatial interpolation methods, ranging from spatial autocorrelation-based methods to methods that explain the occurrence of elements based on biophysical and socio-economic information. Our results are 1 km2 resolution maps of the occurrence of linear landscape elements for Europe. Independent validation of green lines based on aerial photographs showed the best results for interpolation based on regionally estimated regressions relating the occurrence of landscape elements to environmental and socio-economic location factors. The results confirm the importance of the underlying biophysical and socio-economic factors on the presence and abundance of linear landscape elements. However, the total explanatory strength of the considered factors is moderate and a considerable uncertainty in the exact distribution remains. © 2012 Elsevier Ltd. Source

Pompe V.,Wageningen University
Journal of Agricultural and Environmental Ethics | Year: 2013

This article studies the role of entrepreneurship in business ethics and promotes a resource-based ethics. The need for and usefulness of this form of ethics emerge from an analysis of contemporary business ethics that appears to be inefficacious and from a moral business practice formed out of the relationship between the veal calf industry of the VanDrie Group and the Dutch Society for the Protection of Animals (DSPA) in their development and implementation of a Welfare Hallmark for calves. Both organizations created jointly a new meat segment in the market by trust-building and partnership. The relationship shows a remodeling of capabilities of both organizations in the light of co-creation of values. The VanDrie Group established an effectuation of moral goals by being socially sensitive and resource-minded. The DSPA created openings for dialogue by being pragmatic in its ideals. Philosophically, this article sketches a resource-based ethics with Deweyan concepts as end-in-view and transactionality of means and ends. Both organizations show in their entrepreneurship the ability to create, what is called "Room for Maneuver" by exploring, socializing, individualizing, and growing. By maneuvering they set off a form of co-evolution between business and ethics. This article demonstrates what actual moral entrepreneurship can do in bringing about moral change by combining effectively social, policy, norm, and economic related values. © 2012 The Author(s). Source

Finger R.,Wageningen University | El Benni N.,ETH Zurich
Land Use Policy | Year: 2013

Using farm-level panel data, we analyze farmers' adoption decisions with respect to extensive wheat production, which is supported in Switzerland since 1992 with an ecological direct payment scheme. It shows that in particular farms with a small area under wheat, low levels of input use and low wheat yields adopted extensive wheat production in the first phase of the programme. If later adoption phases are included in a duration analysis, the difference in wheat area between adopters and non-adopters vanish. However, the level of wheat yields and input use still tend to be lower for adopters. Hence, less intensive producing farms (with lower yield levels) are much more likely to adopt extensive wheat production, which indicates free-riding effects. In contrast, more intensively producing farms, i.e. those farms that may actually harm the environment, usually not adopt extensive wheat production. Thus, aggregated environmental effects of this programme may not reach its full potential and the effectiveness of voluntary participation in agri-environmental programmes should be re-considered. Moreover, we find that changes in wheat prices and the ecological direct payment significantly influenced adoption decisions. © 2012 Elsevier Ltd. Source

In this article I reviewed the status of dichlorodiphenyltrichloroethane (DDT), used for disease vector control, and its benefits and risks in relation to the available alternatives. Contemporary data on DDT use were obtained from questionnaires and reports as well as a Scopus search to retrieve published articles. Nearly 14 countries use DDT for disease control, and several others are reintroducing DDT. Concerns about the continued use of DDT are fueled by recent reports of high levels of human exposure associated with indoor spraying amid accumulating evidence on chronic health effects. There are signs that more malaria vectors are becoming resistant to the toxic action of DDT. Effective chemical methods are available as immediate alternatives to DDT, but the development of resistance is undermining the efficacy of insecticidal tools. Nonchemical methods are potentially important, but their effectiveness at program level needs urgent study. To reduce reliance on DDT, support is needed for integrated and multipartner strategies of vector control. Integrated vector management provides a framework for developing and implementing effective technologies and strategies as sustainable alternatives to reliance on DDT. Source

Tittonell P.,Wageningen University
Current Opinion in Environmental Sustainability | Year: 2014

Strategies towards agricultural intensification differ on the definitions of sustainability and the variables included in its evaluation. Different notions of the qualifiers of intensification (ecological, sustainable, durable, etc.) need to be unpacked. This paper examines conceptual differences between sustainable and ecological intensification as used in research, development, policy and the industry, particularly with respect to the balance between agriculture and nature. The study compares different discourses on models of intensification that differ in the role nature plays in the actual design of the systems. While sustainable intensification is generally loosely defined, so that almost any model or technology can be labeled under it, ecological intensification proposes landscape approaches that make smart use of the natural functionalities that ecosystems offer. The aim is to design multifunctional agroecosystems that are both sustained by nature and sustainable in their nature. © 2014 Elsevier B.V. Source

Melse-Boonstra A.,Wageningen University | Mackenzie I.,World Health Organization
Nutrition Research Reviews | Year: 2013

Iodine deficiency affects an estimated 241 million school-aged children in the world. Little is known about iodine deficiency in relation to auditory function, except for the fact that deaf-mutism is one of the features of cretinism. In the present review, we documented the scientific knowledge on the role of iodine and hypothyroidism in the auditory system. We found that ear development and hearing function depend on thyroid hormones. Multiple pathways are involved in this, including both inner ear morphology as well as neurological processes. Conductive as well as sensorineural hearing loss is found in studies with animals that were rendered hypothyroidic. In humans, auditory impairment is reported frequently in relation to hypothyroidism, ranging from mild disturbances to severe handicap. Auditory impairment has been related more explicitly to congenital hypothyroidism than to acquired hypothyroidism. The critical period for thyroid function-related hearing maturation is the first and second trimesters of pregnancy. Although only a limited number of studies have directly investigated the relationship between iodine deficiency and auditory function, most studies point toward an association. However, evidence from good randomised controlled trials is lacking. Inclusion of auditory outcomes in iodine supplementation studies is therefore to be recommended, especially for trials in pregnancy. Hearing deficit is an invisible abnormality, but has major consequences for educational and social skills if not detected. In view of this, auditory impairment should be mapped in iodine-deficient areas in order to realistically estimate the magnitude of the problem. © The Author 2013. Source

De Vos W.M.,Wageningen University
Microbial Cell Factories | Year: 2011

Lactic acid bacteria are among the powerhouses of the food industry, colonize the surfaces of plants and animals, and contribute to our health and well-being. The genomic characterization of LAB has rocketed and presently over 100 complete or nearly complete genomes are available, many of which serve as scientific paradigms. Moreover, functional and comparative metagenomic studies are taking off and provide a wealth of insight in the activity of lactic acid bacteria used in a variety of applications, ranging from starters in complex fermentations to their marketing as probiotics. In this new era of high throughput analysis, biology has become big science. Hence, there is a need to systematically store the generated information, apply this in an intelligent way, and provide modalities for constructing self-learning systems that can be used for future improvements. This review addresses these systems solutions with a state of the art overview of the present paradigms that relate to the use of lactic acid bacteria in industrial applications. Moreover, an outlook is presented of the future developments that include the transition into practice as well as the use of lactic acid bacteria in synthetic biology and other next generation applications. © 2011 de Vos; licensee BioMed Central Ltd. Source

Wells J.M.,Wageningen University
Microbial Cell Factories | Year: 2011

Over the past decade it has become clear that lactobacilli and other probiotic and commensal organisms can interact with mucosal immune cells or epithelial cells lining the mucosa to modulate specific functions of the mucosal immune system. The most well understood signalling mechanisms involve the innate pattern recognition receptors such as Toll-like receptors, nucleotide oligomerization domain-like receptors and C-type lectin receptors. Binding of microbe-associated molecular patterns with these receptors can activate antigen presenting cells and modulate their function through the expression of surface receptors, secreted cytokines and chemokines. In vitro the cytokine response of human peripheral blood mononuclear cells and dendritic cells to lactobacilli can be strikingly different depending on both the bacterial species and the strain. Several factors have been identified in lactobacilli that influence the immune response in vitro and in vivo including cell surface carbohydrates, enzymes modifying the structure of lipoteichoic acids and metabolites. In mice mechanistic studies point to a role for the homeostatic control of inducible T regulatory cells in the mucosal tissues as one possible immunomodulatory mechanism. Increasing evidence also suggests that induction of epithelial signalling by intestinal lactobacilli can modulate barrier functions, defensin production and regulate inflammatory signalling. Other probiotic mechanisms include modulation of the T cell effector subsets, enhancement of humoral immunity and interactions with the epithelial-associated dendritic cells and macrophages. A major challenge for the future will be to gain more knowledge about the interactions occurring between lactobacilli and the host in vivo and to understand the molecular basis of innate signalling in response to whole bacteria which trigger multiple signalling pathways. © 2011 Wells; licensee BioMed Central Ltd. Source

Smits M.,University of Sydney | Bush S.R.,Wageningen University
Energy Policy | Year: 2010

The article describes the widespread use of an estimated 60,000 low-head pico-hydropower turbines and well-developed networks of supply and support in the Northern part of the Lao People's Democratic Republic (Lao PDR). This apparent widespread use is contrasted with the policy narratives of key actors in the government, multilateral organisations and the private sector which show an often simplified and overly negative attitude towards pico-hydropower. Based on empirical research carried out in three upland districts and the capital, Vientiane, the paper critically investigates the apparent disjuncture between policy and practice by placing pico-hydropower within the broader political context of rural electrification in the Lao PDR. It is argued that the neglect of pico-hydropower and other off-grid household electrification technologies is a result of an endemic lack of information on which to base policy decisions, the orientation of the government to facilitate large scale foreign investment in large hydropower dams, the universal applicability of solar home systems, and the broader state agenda of centralisation and control over service provision to remote upland areas. © 2009 Elsevier Ltd. All rights reserved. Source

The accuracy of estimated breeding values (EBVs) is an important parameter in livestock genetic improvement. It is used to calculate response to selection and to express the credibility of individual EBVs. Although it is well-known that selection reduces accuracy, this effect is not well-studied and accuracies from genetic evaluations are not adjusted for selection. This work investigates the effect of selection on accuracy of EBVs estimated using best linear unbiased predictors. Results show that accuracies in a selected population may be considerably smaller than the ordinary accuracy from genetic evaluation. Accuracy of the parent average is dramatically reduced by selection, up to a factor of three. Expressions for equilibrium accuracies in selected populations are presented and depend only on the unselected accuracy and the intensity of selection. Thus, schemes with the same unselected accuracy and intensity of selection also have the same equilibrium accuracy and response to selection. At the same unselected accuracy, therefore, schemes based on between-family information do not show greater reduction in response and accuracy because of the Bulmer effect. An example shows that benefit of genomic selection may be underestimated when the effect of selection on accuracy is ignored. Finally, this work argues that the SE of an EBV and the correlation between true and EBVs are different things, and that accuracies should not be adjusted for selection when they primarily serve to indicate the SEs of EBVs. © 2012 Wageningen University. Source

Selakovic S.,University Utrecht | De Ruiter P.C.,Wageningen University | Heesterbeek H.,University Utrecht
Proceedings of the Royal Society B: Biological Sciences | Year: 2014

Infectious agents are part of food webs and ecosystems via the relationship with their host species that, in turn, interact with both hosts and non-hosts. Through these interactions, infectious agents influence food webs in terms of structure, functioning and stability. The present literature shows a broad range of impacts of infectious agents on food webs, and by cataloguing that range, we worked towards defining the various mechanisms and their specific effects. To explore the impact, a direct approach is to study changes in food-web properties with infectious agents as separate species in the web, acting as additional nodes, with links to their host species. An indirect approach concentrates not on adding new nodes and links, but on the ways that infectious agents affect the existing links across host and non-host nodes, by influencing the 'quality' of consumer-resource interaction as it depends on the epidemiological state host involved. Both approaches are natural from an ecological point of view, but the indirect approach may connect more straightforwardly to commonly used tools in infectious disease dynamics. © 2014 The Author(s) Published by the Royal Society. All rights reserved. Source

Mol A.P.J.,Wageningen University
Food Control | Year: 2014

In coping with food quality problems, China relies heavily on state institutions, such as laws and regulations, governmental standards and certification, and inspections and enforcement. Recently, transparency (or information disclosure) has been introduced in China's governance framework to cope with its growing food quality and related sustainability problems. This article investigates to what extent and how China's transparency institutions and practices regarding food production and products play a role in governing food quality and safety. Four forms of food chain transparency are distinguished and assessed: management transparency, regulatory transparency, consumer transparency and public transparency. It is concluded that in China food chain transparency is still in its infancy with respect to governing domestic food production and product quality and safety, and that only with respect to global (export) food chains transparency and accountability put some pressure on agro-food chain actors to improve their performance with respect to food quality and sustainability. By the same token furthering transparency on food quality is desperately needed as the state's food management and control system alone proves not capable to provide safe food that is credible and trusted by domestic consumers. © 2014 Elsevier Ltd. Source

Niks R.E.,Wageningen University
Journal of Integrative Agriculture | Year: 2014

Full nonhost resistance can be defined as immunity, displayed by an entire plant species against all genotypes of a plant pathogen. Interesting biological questions are, whether the genes responsible for the nonhost status of a plant species have a general or a specific effectiveness to heterologous ("nonhost") pathogens? Is the nonhost resistance to pathogens of plant species that are related to the nonhost based on R-genes or on other types of genes? We study this question in barley (Hordeum vulgare L.), which is a near-nonhost to several rusts (Puccinia) of cereals and grasses. By crosses and selection we accumulated susceptibility and developed an experimental line, SusPtrit, with high susceptibility to at least nine different heterologous rust taxa such as the wheat and Agropyron leaf rusts (P. triticina and P. persistens, respectively). At the microscopic level there is also some variation among barley accessions in the degree that the heterologous wheat powdery mildew (Blumeria graminis f.sp. tritici) is able to form haustoria in epidermal cells. So, also the genetics of the variation in level of nonhost resistance to heterologous mildew fungi can be studied in barley. Our data obtained on mapping populations involving three regular nonhost-immune accessions (Vada, Cebada Capa and Golden Promise) suggest that nonhost resistance is the joined effect of multiple, quantitative genes (QTLs) and very occasionally a major gene (R-gene?) is involved. Most QTLs have effect to only one or two heterologous rusts, but some have a wider spectrum. This was confirmed in a set of QTL-NILs. Those QTL-NILs are used to fine-map the effective genes. In some cases, a QTL region with effectiveness to several heterologous rusts might be a cluster of genes with a more narrow spectrum of effectiveness. Our evidence suggests that nonhost resistance in barley to rust and powdery mildew fungi of related Gramineae is not due to R-genes, but to pathogen species-specific quantitative resistance genes. © 2014 Chinese Academy of Agricultural Sciences. Source

Pierik R.,University Utrecht | Ballare C.L.,CONICET | Dicke M.,Wageningen University
Plant, Cell and Environment | Year: 2014

Although plants are sessile organisms, they can modulate their phenotype so as to cope with environmental stresses such as herbivore attack and competition with neighbouring plants. Plant-produced volatile compounds mediate various aspects of plant defence. The emission of volatiles has costs and benefits. Research on the role of plant volatiles in defence has focused primarily on the responses of individual plants. However, in nature, plants rarely occur as isolated individuals but are members of plant communities where they compete for resources and exchange information with other plants. In this review, we address the effects of neighbouring plants on plant volatile-mediated defences. We will outline the various roles of volatile compounds in the interactions between plants and other organisms, address the mechanisms of plant neighbour perception in plant communities, and discuss how neighbour detection and volatile signalling are interconnected. Finally, we will outline the most urgent questions to be addressed in the future. © 2014 John Wiley & Sons Ltd. Source

de Visser J.A.G.M.,Wageningen University | Cooper T.F.,University of Houston | Elena S.F.,Institute Biologia Molecular Y Celular Of Plantas | Elena S.F.,Santa Fe Institute
Proceedings of the Royal Society B: Biological Sciences | Year: 2011

Since Bateson's discovery that genes can suppress the phenotypic effects of other genes, gene interactions-called epistasis-have been the topic of a vast research effort. Systems and developmental biologists study epistasis to understand the genotype-phenotype map, whereas evolutionary biologists recognize the fundamental importance of epistasis for evolution. Depending on its form, epistasis may lead to divergence and speciation, provide evolutionary benefits to sex and affect the robustness and evolvability of organisms. That epistasis can itself be shaped by evolution has only recently been realized. Here, we review the empirical pattern of epistasis, and some of the factors that may affect the form and extent of epistasis. Based on their divergent consequences, we distinguish between interactions with or without mean effect, and those affecting the magnitude of fitness effects or their sign. Empirical work has begun to quantify epistasis in multiple dimensions in the context of metabolic and fitness landscape models.We discuss possible proximate causes (such as protein function and metabolic networks) and ultimate factors (including mutation, recombination, and the importance of natural selection and genetic drift). We conclude that, in general, pleiotropy is an important prerequisite for epistasis, and that epistasis may evolve as an adaptive or intrinsic consequence of changes in genetic robustness and evolvability. © 2011 The Royal Society. Source

De Vries S.C.,Wageningen University
Science Signaling | Year: 2015

In this issue of Science Signaling, Somssich and co-workers use fluorescence techniques to show the dynamics that occur during the activation of two different receptor complexes in living plant cells. Copyright 2015 by the American Association for the Advancement of Science; all rights reserved. Source

Castellanos G.,Leibniz Institute for New Materials | Arzt E.,Leibniz Institute for New Materials | Kamperman M.,Wageningen University
Langmuir | Year: 2011

The effect of viscoelasticity on adhesion was investigated for micropatterned epoxy surfaces and compared to nonpatterned surfaces. A two-component epoxy system was used to produce epoxy compositions with different viscoelastic properties. Pillar arrays with flat punch tip geometries were fabricated with a two-step soft lithography process. Adhesion properties were measured with a home-built adhesion tester using a spherical sapphire probe as a counter-surface. Compared to flat controls, micropatterned epoxy samples with low viscoelasticity (i.e., low damping factors) showed at least a 20-fold reduction in pull-off force per actual contact area for both low (E′ = 2.3 MPa) and high (E′ = 2.3 GPa) storage moduli. This antiadhesive behavior may result from poor contact formation and indicates that the adhesion performance of commonly used elastomers for dry adhesives (e.g., polydimethylsiloxane) is governed by the interfacial viscoelasticity. Adhesion significantly increased with increasing viscoelasticity. Micropatterned samples with high viscoelasticity showed a 4-fold reduction in adhesion for aspect ratio (AR) 1.1 patterns but a 2-fold enhancement in adhesion for AR 2.2 patterns. These results indicate that viscoelasticity can enhance the effect of surface patterning on adhesion and should be considered as a significant parameter in the design of artificial patterned adhesives. © 2011 American Chemical Society. Source

De Weerth C.,Radboud University Nijmegen | Fuentes S.,Radboud University Nijmegen | Puylaert P.,Radboud University Nijmegen | Puylaert P.,Wageningen University | De Vos W.M.,University of Helsinki
Pediatrics | Year: 2013

OBJECTIVES: To provide a comprehensive analysis of the fecal microbiota in infants with colic, as compared with control infants, during their first 100 days of life. METHODS: Microbial DNA of .200 samples from 12 infants with colic and 12 age-matched control infants was extracted and hybridized to a phylogenetic microarray. RESULTS: Microbiota diversity gradually increased after birth only in the control group; moreover, in the first weeks, the diversity of the colic group was significantly lower than that of the control group. The stability of the successive samples also appeared to be significantly lower in the infants with colic for the first weeks. Further analyses revealed which bacterial groups were responsible for colic-related differences in microbiota at age 1 or 2 weeks, the earliest ages with significant differences. Proteobacteria were significantly increased in infants with colic compared with control infants, with a relative abundance that was more than twofold. In contrast, bifidobacteria and lactobacilli were significantly reduced in infants with colic. Moreover, the colic phenotype correlated positively with specific groups of proteobacteria, including bacteria related to Escherichia, Klebsiella, Serratia, Vibrio, Yersinia, and Pseudomonas, but negatively with bacteria belonging to the Bacteroidetes and Firmicutes phyla, the latter of which includes some lactobacilli and canonical groups known to produce butyrate and lactate. CONCLUSIONS: The results indicate the presence of microbial signatures in the first weeks of life in infants who later develop colic. These microbial signatures may be used to understand the excessive crying. The results offer opportunities for early diagnostics as well as for developing specific therapies. Copyright © 2013 by the American Academy of Pediatrics. Source

Jore M.M.,Wageningen University
Cold Spring Harbor perspectives in biology | Year: 2012

The CRISPR/Cas system in prokaryotes provides resistance against invading viruses and plasmids. Three distinct stages in the mechanism can be recognized. Initially, fragments of invader DNA are integrated as new spacers into the repetitive CRISPR locus. Subsequently, the CRISPR is transcribed and the transcript is cleaved by a Cas protein within the repeats, generating short RNAs (crRNAs) that contain the spacer sequence. Finally, crRNAs guide the Cas protein machinery to a complementary invader target, either DNA or RNA, resulting in inhibition of virus or plasmid proliferation. In this article, we discuss our current understanding of this fascinating adaptive and heritable defense system, and describe functional similarities and differences with RNAi in eukaryotes. Source

Sagis L.M.C.,Wageningen University
Physica A: Statistical Mechanics and its Applications | Year: 2012

In this paper, we derive constitutive equations for the surface excess fluxes in multiphase systems, in the context of an extended rational thermodynamics formalism. This formalism allows us to derive MaxwellCattaneo type constitutive laws for the surface extra stress tensor, the surface thermal energy flux vector, and the surface mass flux vector, which incorporate a direct coupling to their corresponding bulk fluxes in the adjacent bulk phases. These constitutive laws also incorporate contributions to the time evolution of the surface excess fluxes from spatial inhomogeneities in these flux fields. These phenomenological equations can be used to model the dynamic behavior of complex viscoelastic interfaces in multiphase systems, in the small deformation limit. © 2011 Elsevier B.V. All rights reserved. Source

Hatna E.,Radboud University Nijmegen | Bakker M.M.,Wageningen University
Ecosystems | Year: 2011

Abandonment of arable land is often assumed to happen mostly in marginal areas where the conditions for arable cultivation are relatively unfavorable, whereas arable expansion is expected to occur mostly in areas with favorable conditions. This assumption, used in many land-use change forecasts, was never properly tested, mainly because the relatively short period of full-coverage land-use inventories did not allow a systematic analysis of the phenomena. With the recent release of CORINE 2006 this has changed. In this article, we explore the typical locations of abandonment and expansion of arable land in Europe during the period 1990-2006 by means of logistic regressions. More specifically, we test whether or not locations of abandonment and expansion can be inferred from the location characteristics of arable land in 1990. If the above assumption holds, this should be the case. We demonstrate that although arable expansion indeed happens in locations that resemble the bulk of arable land in 1990 (the presumably favorable locations), arable abandonment does not necessarily happen in locations that resemble the bulk of uncultivated land (that is, the presumably unfavorable locations). In other words, the assumption does not hold. Particularly, areas close to the road network were found to be associated with both high abandonment rates and high expansion rates, which suggest that abandonment is not limited to areas that are marginal in terms of agricultural production. © 2011 The Author(s). Source

Hoogesteger J.,Wageningen University | Hoogesteger J.,Center for Latin American Research and Documentation
Society and Natural Resources | Year: 2013

Although the community represents a very important level at which existing social capital is used to mobilize resources and collective action in the Andes, many irrigation systems need supracommunity cooperation for their management. Based on a case study of the Guanguilquí and Porotog irrigation systems in the northern Ecuadorian Highlands, this article argues that external nongovernmental organizations can play an important role in facilitating the establishment of new supracommunity autonomous water user associations by (1) developing mutual trust relations and reciprocity between individuals and communities (bonding and bridging); (2) facilitating the establishment of a normative framework (water rights) that provides the rules of interaction; (3) assisting in the creation of relations with external agents (linking); and (4) developing local capacities for organizational and technical irrigation management. Once sturdy water user organizations consolidate, they have the potential to mobilize collective action for issues that stretch beyond the management of irrigation systems. © 2013 Copyright Taylor and Francis Group, LLC. Source

Edens B.,Statistics Netherlands | Edens B.,VU University Amsterdam | Hein L.,Wageningen University
Ecological Economics | Year: 2013

In spite of an increasing interest in environmental economic accounting, there is still very limited experience with the integration of ecosystem services and ecosystem capital in national accounts. This paper identifies four key methodological challenges in developing ecosystem accounts: the definition of ecosystem services in the context of accounting, their allocation to institutional sectors; the treatment of degradation and rehabilitation, and valuing ecosystem services consistent with SNA principles. We analyze the different perspectives taken on these challenges and present a number of proposals to deal with the challenges in developing ecosystem accounts. These proposals comprise several novel aspects, including (i) presenting an accounting approach that recognizes that most ecosystems are strongly influenced by people and that ecosystem services depend on natural processes as well as human ecosystem management; and, (ii) recording ecosystem services as either contributions of a private land owner or as generated by a sector 'Ecosystems' depending on the type of ecosystem service. We also present a consistent approach for recording degradation, and for applying monetary valuation approaches in the context of accounting. © 2013 Elsevier B.V. Source

We analyze the sensitivity of crop management under current and future climate scenarios to changes in economic boundary conditions. In particular, we focus on the effects of changing price risks. We combine a bio-economic modeling approach and a crop growth model CropSyst with an economic model that represents the decision making process of a risk-averse farmer. We apply the models to irrigated maize production in Switzerland. To analyze the sensitivity of optimal water and nitrogen use to likely future states of several economic variables, we conduct sensitivity analyses with respect to changes in price variability, the price-yield correlation, water and maize prices as well as farmers' risk preferences. Results show that climate change leads to a strong increase in optimal water use for irrigation, with consequent increases in maize yields. However, our analysis also reveals that the consideration of economic drivers for farmers' irrigation decisions is indispensable. Strong effects on optimal water use are found for changes in crop (positive) and water (negative) prices. We also find strong implications of risk aversion and price variability on irrigation decisions. A doubling of price variability, which would represent a shift from the current Swiss situation to price variability levels in its neighboring countries, could reduce optimal water use by up to 40%. We conclude that investigations of water demand should consider, beyond expectations on output and input price levels, also the variability of prices. © 2012 Elsevier B.V. Source

Miralles D.G.,University of Bristol | Van Den Berg M.J.,Ghent University | Teuling A.J.,Wageningen University | De Jeu R.A.M.,VU University Amsterdam
Geophysical Research Letters | Year: 2012

Land-atmospheric interactions are complex and variable in space and time. On average soil moisture-temperature coupling is expected to be stronger in transition zones between wet and dry climates. During heatwaves anomalously high coupling may be found in areas of soil moisture deficit and high atmospheric demand of water. Here a new approach is applied to satellite and in situ observations towards the characterization of regions of intense soil moisture-temperature coupling, both in terms of climatology and anomalies during heatwaves. The resulting average summertime coupling hot spots reflect intermediate climatic regions in agreement with previous studies. Results at heatwave-scale suggest a minor role of soil moisture deficit during the heatwave of 2006 in California but an important one in the 2003 event in Western Europe. Progress towards near-real time satellite products may allow the application of the approach to aid prediction and management of warm extremes. © 2012. American Geophysical Union. All Rights Reserved. Source

Finger R.,Wageningen University
Ecological Indicators | Year: 2013

Water footprints for a crop produced in a specific country are often provided as mean values. However, mean values do not account for the spatial heterogeneity of water footprints within a country that is caused by heterogeneous climate conditions and production techniques. To sufficiently inform decision makers, the underlying heterogeneity should thus also be presented. We provide an illustrate example of seed cotton production in 19 regions in Brazil and China. Even though grey water footprints in Brazil are on average smaller, it also contains the highest possible grey water footprint across all regions. To avoid misleading inference on water footprint estimates, their spatial heterogeneity should be indicated. This will enable decision makers to consider trade-offs between average values and potential extremes. © 2013 Elsevier Ltd. Source

Ferrihydrite (Fh) is an excellent model for understanding nanoparticle behavior in general. Moreover, Fh is one of the most important Fe (hydr) oxides in nature. Fh particles can be extremely small leading to a very high reactive surface area that changes its chemical potential, strongly affecting the solubility, nucleation, and stability. These characteristics can be coupled to the interfacial Gibbs free energy, being γ=0.186 ± 0.01Jm-2 for Fh. The surface free energy has a relatively large contribution of surface entropy (-TSsurf=+0.079 ± 0.01 J m-2). The surface entropy is primarily related to the formation of surface groups by chemisorption of water (-17.1Jmol-1K-1), for Fh equivalent with +0.064 ± 0.002 J m-2 at a surface loading NH2O=12.6μmolm-2. The entropy contribution of physisorbed water has been estimated by analyzing, as model, the surface enthalpy, entropy, and Gibbs free energy of the principal interfaces of H2O, i.e. ice-water-gas. It is about 20% of the contribution of chemisorbed water. The surface enthalpy of Fh is exceptionally low (Hsurf=+0.107 ± 0.01 Jm-2), which can be explained by surface depletion (SD) of relatively unstable Fe polyhedra, or similarly, by additional surface loading of the non-depleted mineral core with specific Fe polyhedra for stabilization. The experimental enthalpy of Fh formation varies linearly with the surface area and correctly predicts the enthalpy value for the mineral core (-405.2 ± 1.2 kJ mol FeO3/2), being similar to the literature value for Fh as virtual bulk material (-406.7 ± 1.5 kJ mol FeO3/2) obtained with MO/DFT computations. The thermochemical quantities of the mineral core and surface are essentially the same for the entire range of Fh samples, in line with the SD model. The solubility of Fh suspensions as a whole may differ from the behavior of individual particles due to polydispersity. For 2-line Fh, the overall solubility is logKso~-38.5 ± 0.1 and for prolongedly aged 6-line Fh, logKso~-39.5 ± 0.1. The smallest Fh particles in a suspension react according to the Ostwald-Freundlich equation (RTδlnKso=2/3 γA), but the suspension as a whole apparently reacts according to the Ostwald equation (RTδln Kso=γA). This difference can be explained by the observed linear relation between the minimum (dmin) and mean (dmean) particle size (dmin=2/3 dmean) in Fh suspensions. With best estimates for the surface entropy of goethite, hematite, and lepidocrocite, predictions show that Fh becomes thermodynamically unstable above a diameter of ~8.0. nm at 298. K, allowing formation of nano-goethite and nano-hematite, as experienced experimentally at Ostwald ripening. More generally, one observes that metal (hydr) oxides with the highest chemical stability also have the highest mean surface Gibbs free energy, which can be considered as the scientific explanation of the empirical rule of Ostwald-Lussac. In addition, it is shown that the surface Gibbs free energies of metal (hydr) oxides increase with the mean metal coordination number of oxygen in the lattices following the order: oxides > oxyhydroxides. > hydroxides. © 2015 Elsevier Ltd. Source

Van Der Poel W.H.,Wageningen University | Van Der Poel W.H.,University of Liverpool
Current Opinion in Virology | Year: 2014

Hepatitis E virus (HEV), genus Hepevirus, family hepeviridae is a main cause of epidemic hepatitis in developing countries and single cases of hepatitis in higher income countries. There are at least four HEV genotypes which have different epidemiologic and clinical features. Hepatitis E viruses are often transmitted via food and environmental routes. The actual role of these transmission routes in the spread of HEV can depend on the virus genotype, the environmental conditions, the hygienic conditions and the types of foods consumed. In this review food and environmental routes of HEV transmission are discussed to raise the awareness regarding the focal points for the development of accurate prevention and control strategies of HEV infection, food safety and public health protection © 2014 Elsevier B.V. Source

Kruijer W.,Wageningen University
Genetics | Year: 2016

Additive genetic variance in natural populations is commonly estimated using mixed models, in which the covariance of the genetic effects is modeled by a genetic similarity matrix derived from a dense set of markers. An important but usually implicit assumption is that the presence of any nonadditive genetic effect increases only the residual variance and does not affect estimates of additive genetic variance. Here we show that this is true only for panels of unrelated individuals. In the case that there is genetic relatedness, the combination of population structure and epistatic interactions can lead to inflated estimates of additive genetic variance. © 2016 by the Genetics Society of America. Source

This paper presents the findings of a study on the governance of seed conducted in the framework of a participatory plant breeding (PPB) programme, based on a multi-year inquiry with a panel of ten Syrian households. The study assessed the interactions between governance regimes regulating the rights to access and control genetic resources at international and national level, compared to the actual ability of the respondent women farmers to access and control the seed of varieties they co-developed with the PPB programme. The paper argues that gender equal access to seed can "optimally" contribute to enhancing household food security in small scale farming. The paper also argues that to support a gender-equal access to seed in the respondent households legislation needs to explicitly protect the rights of women farmers to access and share the benefits of genetic material and draw from empirical evidence of the actual access to and control of seed at ground level. © 2013 United Nations. Source

Aim A consistent set of root characteristics for herbaceous plants growing in water-limited environments has been developed based on compilations of global root databases, but an overall analysis of why these characteristics occur is still missing. The central question in this study is whether an ecohydrological model which assumes that rooting strategies reflect maximization of transpiration can predict the variations in rooting strategies of plants in dry environments. Location Arid ecosystems across the globe. Methods A model was used to explore interactions between plant biomass, root-shoot allocation, root distribution, rainfall, soil type and water use by plants. Results Model analyses showed that the predicted shifts in rooting depth and root-shoot allocation due to changes in rainfall, soil type and plant biomass were quite similar to observed shifts. The model predicted that soil type, annual rainfall and plant biomass each had strong effects on the rooting strategies that optimize transpiration, but also that these factors have strong interactive effects. The process by which plants compete for water availability (soil evaporation or drainage) especially affected the depth distribution of roots in the soil, whereas the availability of rainfall mainly affected the optimal root-shoot allocation strategy. Main conclusions The empirically observed key patterns in rooting characteristics of herbaceous plant species in arid environments could be explained in this theoretical study by using the concept of hydrological optimality, represented here by the maximization of transpiration. © 2010 Blackwell Publishing Ltd. Source

Bose P.,Wageningen University
International Forestry Review | Year: 2011

The current trend in forest tenure reform promotes identity-based categories, such as indigenous people, on the assumption that this provides better access to forest resources for marginalized groups. India's historic Forest Rights Act of 2006 recognizes the traditional rights of the scheduled tribes and other forest-dependent people dwelling in and around forestlands. This paper examines the politics of individual and collective access to forestland and the political representation of Bhil tribal women in the semi-arid Banswara district, Rajasthan, India. Data were collected through in-depth interviews with 54 informants, and two focus group discussions. A rights-based access approach was used to analyse outcomes of forest tenure reform on tribal women's access to forestland, and inclusion in, and/or exclusion from, collective decision making about forestland management. The findings indicate that the new identity-based forest tenure reform is mere tokenism and hinders rather than promotes tribal women's political empowerment and access to forest-based resources. Source

Temme A.J.A.M.,Wageningen University | Verburg P.H.,VU University Amsterdam
Agriculture, Ecosystems and Environment | Year: 2011

Spatial maps of agricultural intensity are needed for analyses of environmental issues, including biodiversity changes. We present a method to produce such maps for Europe. While most studies beyond farm level focus on land cover change only, this paper focuses on spatial variation in land use intensity and its dynamics.Our method defines agricultural land use intensity in terms of nitrogen input. For arable land, it combines field observations with administrative-level statistics to assess probability of occurrence for three land use intensity classes. For grassland, it uses maps of livestock density to assess probability of occurrence for two intensity classes. Agricultural land is spatially allocated to intensity classes using an algorithm that downscales intensity changes simulated with an agricultural economic model.Our results are 1km2 resolution maps of classified agricultural land use intensity in the year 2000. We illustrate the method by exploring changes in the spatial pattern of land use intensity for a financial policy reform scenario in the year 2025. Results indicate spatial heterogeneity in land use intensity across European countries, including large differences in intensity between countries, between regions, but also within regions.Our method could be improved with smaller-resolution agricultural statistics and broader intensity indicators. © 2010 Elsevier B.V. Source

Horlings L.G.,Wageningen University | Marsden T.K.,University of Cardiff
Global Environmental Change | Year: 2011

The challenge to produce enough food is more urgent than ever. We argue that the dominant food regime has responded to this challenge by a 'narrow' ecological modernisation process within agriculture which may decrease environmental effects to a certain extent, but also causes new negative side-effects and exposes some important missing links. In this paper we explore what might be a 'real' ecological modernisation process, including social, cultural, spatial and political aspects. The central question concerns: is there evidence in practice that agro-ecological approaches can contribute to the future demand for food production, especially in developing countries? We illustrate this by describing examples from Africa, Brazil and China, showing a rich variety of such approaches in agricultural practices. Our conclusion is that agro-ecological approaches could significantly contribute to 'feeding the world', and thereby contribute to a 'real green revolution'; but that this requires a more radical move towards a new type of regionally embedded agri-food eco-economy. This is one which includes re-thinking market mechanisms and organisations, an altered institutional context, and is interwoven with active farmers and consumers' participation. It also requires a re-direction of science investments to take account of translating often isolated cases of good practice into mainstream agri-food movements. © 2011 Elsevier Ltd. Source

Sagis L.M.C.,Wageningen University | Sagis L.M.C.,ETH Zurich | Fischer P.,ETH Zurich
Current Opinion in Colloid and Interface Science | Year: 2014

Fluid-fluid interfaces stabilized by proteins, protein aggregates, polymers, or colloidal particles, tend to have a complex microstructure. Their response to an applied deformation is often highly nonlinear, even at small deformation (rates). The nonlinearity of the response is a result of changes in the interfacial microstructure. Most of the studies on interfacial rheology of complex interfaces currently available in the scientific literature, focus on the linear response regime. Since multiphase systems such as emulsions or foam are routinely exposed to large and fast deformations, characterization of the nonlinear response of complex interfaces is highly relevant. In this paper we review the recent work on nonlinear rheology of complex interfaces, both in shear and dilatational deformations. We also discuss several methods currently available for analyzing nonlinear interfacial rheology data, and recent progress in modeling nonlinear interfacial rheology, using nonequilibrium thermodynamic frameworks. © 2014 Elsevier Ltd. Source

Verweij M.F.,Wageningen University | Houweling H.,Health Council of the Netherlands
Vaccine | Year: 2014

Given the ethical aspects of vaccination policies and current threats to public trust in vaccination, it is important that governments follow clear criteria for including new vaccines in a national programme. The Health Council of the Netherlands developed such a framework of criteria in 2007, and has been using this as basis for advisory reports about several vaccinations. However, general criteria alone offer insufficient ground and direction for thinking about what the state ought to do. In this paper, we present and defend two basic ethical principles that explain why certain vaccinations are the state's moral-political responsibility, and that may further guide decision-making about the content and character of immunisation programmes. First and foremost, the state is responsible for protecting the basic conditions for public health and societal life. Secondly, states are responsible for promoting and securing equal access to basic health care, which may also include certain vaccinations. We argue how these principles can find reasonable support from a broad variety of ethical and political views, and discuss several implications for vaccination policies. © 2014 Elsevier Ltd. Source

Quinn J.,Colorado State University | Quinn J.,Solix Biofuels Inc | de Winter L.,Wageningen University | Bradley T.,Colorado State University
Bioresource Technology | Year: 2011

The scalability of microalgae growth systems is a primary research topic in anticipation of the commercialization of microalgae-based biofuels. To date, there is little published data on the productivity of microalgae in growth systems that are scalable to commercially viable footprints. To inform the development of more detailed assessments of industrial-scale microalgae biofuel processes, this paper presents the construction and validation of a model of microalgae biomass and lipid accumulation in an outdoor, industrial-scale photobioreactor. The model incorporates a time-resolved simulation of microalgae growth and lipid accumulation based on solar irradiation, species specific characteristics, and photobioreactor geometry. The model is validated with 9. weeks of growth data from an industrially-scaled outdoor photobioreactor. Discussion focuses on the sensitivity of the model input parameters, a comparison of predicted microalgae productivity to the literature, and an analysis of the implications of this more detailed growth model on microalgae biofuels lifecycle assessment studies. © 2011 Elsevier Ltd. Source

Clevers J.G.P.W.,Wageningen University | Gitelson A.A.,University of Nebraska - Lincoln
International Journal of Applied Earth Observation and Geoinformation | Year: 2013

Sentinel-2 is planned for launch in 2014 by the European Space Agency and it is equipped with the Multi Spectral Instrument (MSI), which will provide images with high spatial, spectral and temporal resolution. It covers the VNIR/SWIR spectral region in 13 bands and incorporates two new spectral bands in the rededge region, which can be used to derive vegetation indices using red-edge bands in their formulation. These are particularly suitable for estimating canopy chlorophyll and nitrogen (N) content. This band setting is important for vegetation studies and is very similar to the ones of the Ocean and Land Colour Instrument (OLCI) on the planned Sentinel-3 satellite and the Medium Resolution Imaging Spectrometer (MERIS) on Envisat, which operated from 2002 to early 2012. This paper focuses on the potential of Sentinel-2 and Sentinel-3 in estimating total crop and grass chlorophyll and N content by studying in situ crop variables and spectroradiometer measurements obtained for four different test sites. In particular, the red-edge chlorophyll index (CIred-edge), the green chlorophyll index (CIgreen) and the MERIS terrestrial chlorophyll index (MTCI) were found to be accurate and linear estimators of canopy chlorophyll and N content and the Sentinel-2 and-3 bands are well positioned for deriving these indices. Results confirm the importance of the red-edge bands on particularly Sentinel-2 for agricultural applications, because of the combination with its high spatial resolution of 20 m. © 2012 Elsevier B.V. Source

Gentine P.,Columbia University | Holtslag A.A.K.,Wageningen University