Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Pluronic F127/Pluronic P123/vitamin E TPGS mixed micellesfor oral delivery of mangiferin and quercetin: Mixture-design optimization, micellization, and solubilization behavior
Thanitwatthanasak, Santi ; Sagis, L.M.C. ; Chitprasert, Pakamon - \ 2019
Journal of Molecular Liquids 274 (2019). - ISSN 0167-7322 - p. 223 - 238.
mangiferin - Quercetin - mixed micelles - mixture design optimization - micellization - solubilization
Mixed micelles (MMs) of Pluronic F127 (F127), Pluronic P123 (P123), and Vitamin E TPGS (TPGS) copolymers were prepared by the thin-film sonication method to encapsulate two phenolics with different polarities: magniferin (MGF) and quercetin (QCT). Mixture design was applied for the multi-response optimization of formulations of MGF-loaded MMs (MGF-MMs) and QCT-loaded MMs (QCT-MMs) with high encapsulation efficiency (EE) and drug loading (DL), but low critical micelle concentration (CMC). The optimal mass fractions of F127/P123/TPGS were 0.120/0.328/0.552 for MFG-MMs and 0.131/0.869/0.000 for QCT-MMs, providing EE (>95% (w/w)) and DL (>4.5% (w/w)) higher than those obtained by their individual copolymer components. The CMCs of MFG/QCT-MMs, detected by dynamic light scattering (DLS), were 0.009 ± 0.001 and 0.011 ± 0.001% (w/v), respectively, slightly lower than those obtained by profile analysis tensiometry (PAT). The results revealed that the PAT-CMC represented complete MM formation, while the DLS-CMC detected mono-molecular micelles. The MGF/QCT-MMs showed spherical morphology with diameters of 14.26 ± 0.52 and 21.50 ± 0.37 nm, and their zeta-potentials were −2.89 ± 1.70 and −3.22 ± 1.92 mV, respectively. Nuclear overhauser effect spectroscopy showed that MGF located in both hydrophilic and hydrophobic parts of MMs by orienting its xanthone backbone towards the core, but its glucoside close to the corona. QCT was preferentially located in the PPO core. Both MGF/QCT-MMs had excellent dissolution ability and sustained release in the simulated gastrointestinal environment. This study demonstrated that mixture design was successfully applied for multi-response optimization MM formulations of MGF and QCT, and the developed MMs had potential application as nanoparticle-based drug delivery systems.
Research challenges for cultural ecosystem services and public health in (peri-)urban environments
Chen, Xianwen ; Vries, Sjerp de; Assmuth, Timo ; Dick, Jan ; Hermans, Tia ; Hertel, Ole ; Jensen, Anne ; Jones, Laurence ; Kabisch, Sigrun ; Lanki, Timo ; Lehmann, Irina ; Maskell, Lindsay ; Norton, Lisa ; Reis, Stefan - \ 2019
Science of the Total Environment 651 (2019). - ISSN 0048-9697 - p. 2118 - 2129.
Cultural ecosystem services - Nature-based solutions - Public health - Urban green/blue infrastructure

Urbanization is a global trend, and consequently the quality of urban environments is increasingly important for human health and wellbeing. Urban life-style is typically associated with low physical activity and sometimes with high mental stress, both contributing to an increasing burden of diseases. Nature-based solutions that make effective use of ecosystem services, particularly of cultural ecosystem services (CES), can provide vital building blocks to address these challenges. This paper argues that, the salutogenic, i.e. health-promoting effects of CES have so far not been adequately recognised and deserve more explicit attention in order to enhance decision making around health and wellbeing in urban areas. However, a number of research challenges will need to be addressed to reveal the mechanisms, which underpin delivery of urban CES. These include: causal chains of supply and demand, equity, and equality of public health benefits promoted. Methodological challenges in quantifying these are discussed. The paper is highly relevant for policy makers within and beyond Europe, and also serves as a review for current researchers and as a roadmap to future short- and long-term research opportunities.

Long-term effects of wild ungulates on the structure, composition and succession of temperate forests
Ramirez Chiriboga, J.I. ; Jansen, P.A. ; Ouden, J. den; Goudzwaard, L. ; Poorter, L. - \ 2019
Forest Ecology and Management 432 (2019). - ISSN 0378-1127 - p. 478 - 488.
Ungulates in temperate regions are increasing in range and abundance, leading to concerns that browsing and trampling reach levels that hamper tree recruitment and forest regeneration. However, studies that actually quantify the long-term effects of ungulates on forest succession are scarce. Here, we use a chronosequence of ungulate exclosures (fenced) and control (unfenced) plots to assess the long-term effects of ungulates on forest structure, diversity and litter depth in forests on poor sandy soils at the Veluwe, the Netherlands, which have moderate ungulate densities ( = 13.6 ungulates km−2). We surveyed the vegetation in 27 paired fenced and unfenced plots that ranged from 1 to 33 years old, and measured seven variables to characterize forest structure (stem density, canopy cover and understory vegetation cover), composition (Shannon diversity, species richness and conifer proportion) and leaf litter depth. We found on average that fencing compared to unfencing reduced understory vegetation cover (fenced = 64.3 ± 20.2%, unfenced = 80.3 ± 19.4%), increased canopy cover (fenced = 47.4 ± 30.1%, unfenced = 29.3 ± 21.1%), tree species richness (fenced = 4.5 ± 1.3 spp., unfenced = 2.7 ± 1.2 spp.), tree Shannon diversity (fenced = 1.1 ± 0.3 index, unfenced = 0.7 ± 0.3 index) and litter layer depth (fenced = 4.4 ± 1.4 cm, unfenced = 2.4 ± 1.1 cm). While fenced plots developed woody vegetation with palatable broadleaved species such as Betula pendula, Betula pubescens, Prunus serotina, and Quercus robur, unfenced plots were not associated with any particular tree species. Our results show that current ungulate densities in this system have pronounced long-term effects on forest structure, composition and litter depth, implying that ungulates can slow down natural succession of temperate forest, from light demanding to shade tolerant species, by keeping the system in an arrested state consisting of light demanding species.
Priorities and opportunities in the application of the ecosystem services concept in risk assessment for chemicals in the environment
Faber, J.H. ; Marshall, Stuart ; Brink, P.J. van den; Maltby, Lorraine - \ 2019
Science of the Total Environment 651 (2019). - ISSN 0048-9697 - p. 1067 - 1077.
The ecosystem services approach has gained broad interest in regulatory and policy circles for use in ecological risk assessment. Whilst identifying several challenges, scientific experts from European regulatory authorities,
the chemical industry and academia considered the approach applicable to all chemical sectors and potentially contributing to greater ecological relevance for setting and assessing environmental protection goals compared to current European regulatory frameworks for chemicals. These challengeswere addressed in workshops to develop a common understanding across stakeholders on how the ecosystem services concept might be used in chemical risk assessment and what would need to be done to implement it. This paper describes the consensus
outcome of those discussions. Knowledge gaps and research needs were identified and prioritised, exploring the use of novel approaches from ecology, ecotoxicology and ecological modelling. Where applicable, distinction is
made between prospective and retrospective ecological risk assessment. For prospective risk assessment the development of environmental scenarios accounting for chemical exposure and ecological conditions was designated
as a top priority. For retrospective risk assessment the top priority research need was development of reference conditions for key ecosystem services and guidance for their derivation. Both prospective and retrospective
risk assessment would benefit from guidance on the taxa and measurement endpoints relevant to specific ecosystem services and from improved understanding of the relationships between measurement endpoints
fromstandard toxicity tests and the ecosystemservices of interest (i.e. assessment endpoints). The development of mechanistic models, which could serve as ecological production functions, was identified as a priority.
A conceptual framework for future chemical risk assessment based on an ecosystem services approach is presented.
presented.
©
What future for collaborative consumption? A practice theoretical account
Fraanje, Walter ; Spaargaren, G. - \ 2019
Journal of Cleaner Production 208 (2019). - ISSN 0959-6526 - p. 499 - 508.
collaborative consumption - practice theory - social change
Collaborative consumption indicates the emergence and rapid spread of a new set of consumption practices. Originally praised as an antidote to an unsustainable market economy, there is growing concern that collaborative consumption increasingly follows a conventional market rationality of payments
and profits, thereby undermining its initial social and ‘civil society’ aspects. This article investigates the future of collaborative consumption through case studies of the Peerby and MyWheels platforms, which represent new social practices of borrowing and renting. We use the sociological theories of Theodore Schatzki and Randall Collins to analyse the key factors that determine the present and future trajectories of these practices. We show how human agency and emotions in a dynamic between companies, practices, and practitioners are crucial in shaping the future of collaborative consumption. The findings suggest two diverging trajectories: one that sticks to the social aspects of connecting
people through sharing things, and another that heads towards impersonal forms of collaborative consumption. The latter is primarily organized by companies, which introduce new rules (payments and insurances) and technologies (drones and autonomous vehicles) to make the shared use of things more fast, efficient, and profitable.
Assessing social innovation across offshore sectors in the Dutch North Sea
Soma, K. ; Burg, S.W.K. van den; Selnes, T. ; Heide, C.M. van der - \ 2019
Ocean & Coastal Management 167 (2019). - ISSN 0964-5691 - p. 42 - 51.
Maritime spatial planning - Social innovation - Dutch North Sea - Offshore mussel producton - Offshore seaweed production - Offshore wind production
Activities in the North Sea are intensifying. The European Union instructs maritime spatial planning across member states that motivates coordination of activities, stakeholders, policies, governance levels and nations. Social innovation is a concept addressing ways in which changing attitudes, behaviour or perceptions are leading to new and improved ways of acting jointly within a group and beyond. The main aim of this article is to explore social innovation in maritime spatial planning. Instances of social innovation are assessed across three sectors in the Dutch North Sea: the offshore wind energy, the offshore mussel cultivation and the offshore seaweed farming. The assessment shows that, while existing systems of social innovation are favourable to the offshore wind expansions, the barriers to grow for the offshore mussel sector include low willingness to change within the sector, and disadvantageous governmental support to change. The offshore seaweed farming is in a stage of re-organisation of not yet developed regulations, rules and norms for production offshore and enhanced cooperation, with unsure outcomes. Maritime spatial planning can play a more influential role for change if tackling main challenges, including inclusiveness, accountability, private user rights and realisation of organisation or reorganisation, and if making use of the potentials of knowledge brokers when sectors are advancing with new technologies.
Effect of dietary protein to energy ratio on performance of nile tilapia and food web enhancement in semi-intensive pond aquaculture
Kabir, K.A. ; Schrama, J.W. ; Verreth, J.A.J. ; Phillips, M.J. ; Verdegem, M.C.J. - \ 2019
Aquaculture 499 (2019). - ISSN 0044-8486 - p. 235 - 242.
Food web - N utilization - P:E ratio - Pond

When fish have only access to formulated feed, the optimal dietary protein to energy ratio (P:E) for tilapia ranges between 18 and 23 g.MJ−1. In pond culture, where natural foods complement administrated feed, increasing the carbon:nitrogen (C:N) ratio stimulates the natural food productivity. This study assessed if lowering the dietary P:E ratio (and thus increasing the C:N ratio of the feed input in the pond) below the optimal P:E ratio affects fish productivity, food web dynamics and nitrogen balances in semi-intensively managed tilapia ponds. Twelve ponds, each divided into three equally-sized compartments, were assigned to test the effect of two diets, which differed in P:E ratio (19 vs. 14 g.MJ−1). Three feeding levels (no, “low” and “high”) were nested in each pond in a split plot design. Initial fish biomass was 1166 (±16) g.compartment−1 and the experiment lasted 60 days. Decreasing P:E ratio enhanced tilapia production and specific growth rate (P <.05; 1195 vs. 985 g.compartment−1 and 1.76 vs 1.55%.d−1). Body composition of tilapia was unaffected by diet and feeding level. Despite the difference in performance, final fat content was 5% of body weight and unaffected by treatments. Averaged over both diets, survival and feed conversion ratio increased with increasing feeding level (P <.001). Diet composition did not alter measured water quality, and abundance and diversity of the related parameters of the food web. The total amount of N accumulated in the pond was lower with the low P:E ratio diet (i.e., low protein diet). The data on N gain and N balance at the pond level suggest that the food web productivity was stimulated by reducing the dietary P:E ratio below the reported optimal levels in the literature. It is hypothesized that the optimal dietary P:E ratio is dependent on the culture intensity (extensive, semi-extensive or intensive pond culture).

Sensor-based management of container nursery crops irrigated with fresh or saline water
Incrocci, Luca ; Marzialetti, Paolo ; Incrocci, Giorgio ; Vita, Andrea Di; Balendonck, Jos ; Bibbiani, Carlo ; Spagnol, Serafino ; Pardossi, Alberto - \ 2019
Agricultural Water Management 213 (2019). - ISSN 0378-3774 - p. 49 - 61.
The objective of this study was to design and test a prototype fertigation controller for the management of container ornamental nursery stocks irrigated with different water sources, including saline water or reclaimed municipal/industrial wastewater. The prototype could schedule irrigation in various ways, i.e. as a time clock, or by means of a soil moisture dielectric sensor, or using a crop evapotranspiration (ET) model. The prototype also monitored the salinity in the root zone using a dielectric sensor that measured both substrate moisture and electrical conductivity (EC), or a probe measuring the EC of the water draining out of the containers. Excessive substrate salinization of the containers irrigated with saline water (containing 10 mM of sodium chloride) was prevented by the automated adoption of a series of measures: irrigation with fresh water or a mixture of fresh water and saline water; progressive increase of irrigation dose for each event, and progressive reduction of fertilizer concentration in the nutrient solution delivered to the crop. The system was tested in three experiments conducted in Pistoia (Italy) between 2008 and 2010 with two ornamental species: Photinia × fraseri Dress (a salt-medium tolerant species) and Prunus laurocerasus L. (a salt-sensitive species). When irrigation with fresh water was controlled with a dielectric sensor or an ET model, total irrigation water use and the loss of both N and P were reduced by 17% to 84% compared with the time-controlled irrigation. The sensor-based control of saline water irrigation reduced the salinity effects on dry matter accumulation in both species; however, it did not prevent the occurrence of leaf damages (leaf scorch) on Prunus plants, which were unmarketable by the end of growing season. On the contrary, no leaf damages were visible on Photinia plants irrigated with saline and/or fresh water, such that all were classified in the top quality market category. The controller developed in this work could be used in commercial nurseries to improve profitability and sustainability of container hardy ornamental nursery stock production.
The relevance of spatial scales in nutrient balances on dairy farms
Leeuwen, M.W.J. van; Middelaar, C.E. van; Oenema, J. ; Dam, J.C. van; Stoorvogel, J.J. ; Stoof, C.R. ; Boer, I.J.M. de - \ 2019
Agriculture, Ecosystems and Environment 269 (2019). - ISSN 0167-8809 - p. 125 - 139.
Policy makers and farmers use tools, such as a nutrient balance, to gain insight into the environmental impact of agricultural practices. A discrepancy, however, exists between the needs of policy makers and farmers, about the use and the spatial scale of such tools. Farm balances calculate nutrient balances across all agricultural fields within a farm without distinguishing separate fields, whereas field balances calculate a nutrient balance on a delineated field. For farmers, a nutrient balance at field level is more useful than at crop or farm level, because decision making and fine-tuning management occurs at the field level. A field balance, however, requires more detailed data than a farm balance and therefore is less easy to implement. As soil types influence nutrient balances, we hypothesize that if within-farm variation in soil types is low, there is no need to replace a farm balance by a field balance. To test this hypothesis, we computed nutrient balances at farm and field level on five Dutch dairy farms (three on sand, two on clay), varying in degree of within-farm variation in soil series. A full year of soil nitrogen (N) and phosphorus (P) input and output data on farm and field level were provided by farmers, while soil variation was determined using the Dutch 1:50.000 soil map. The Annual farm Nutrient Cycle Assessment (ANCA) was used to calculate soil N and P surpluses, and soil nutrient fluxes such as nitrate leaching and nitrous oxide emission at farm and field level. Even on farms with few soil series, a considerable variation in N and P inputs, outputs and balances across fields was found, due to management differences and soil properties not represented by the soil map. Furthermore, field-level balances better represented nitrogen leaching than farm-level balances on farms with diverse soils (reflected by different leaching factors) and negative nitrogen field balances (deficits). Also, using field balances, for one case study farm the highest soil N surplus (kg ha−1) was found on grass fields with the highest risk of N leaching. A field balance, therefore, provides more meaningful information than a farm balance when variation in soil types and/or management factors is found within the farm, because soil types and management factors affect N and P balances, N leaching and N emissions. For farms with the highest variation in soil types and/or management, we recommend using field-level nutrient balances in order to detect extreme surpluses, deficits, leaching and/or emissions, to improve management decisions.

Towards globally customizable ecosystem service models
Martínez-López, Javier ; Bagstad, Kenneth J. ; Balbi, Stefano ; Magrach, Ainhoa ; Voigt, Brian ; Athanasiadis, Ioannis ; Pascual, Marta ; Willcock, Simon ; Villa, Ferdinando - \ 2019
Science of the Total Environment 650 (2019)2. - ISSN 0048-9697 - p. 2325 - 2336.
ARIES - Cloud-based modelling - Context-aware modelling - decision making - semantic modelling - spatial multi-criteria analysis
Scientists, stakeholders and decision makers face trade-offs between adopting simple or complex approaches when modeling ecosystem services (ES). Complex approaches may be time- and data-intensive, making them more challenging to implement and difficult to scale, but can produce more accurate and locally specific results. In contrast, simple approaches allow for faster assessments but may sacrifice accuracy and credibility. The ARtificial Intelligence for Ecosystem Services (ARIES) modeling platform has endeavored to provide a spectrum of simple to complex ES models that are readily accessible to a broad range of users. In this paper, we describe a series of five “Tier 1” ES models that users can run anywhere in the world with no user input, while offering the option to easily customize models with context-specific data and parameters. This approach enables rapid ES quantification, as models are automatically adapted to the application context. We provide examples of customized ES assessments at three locations on different continents and demonstrate the use of ARIES' spatial multi-criteria analysis module, which enables spatial prioritization of ES for different beneficiary groups. The models described here use publicly available global- and continental-scale data as defaults. Advanced users can modify data input requirements, model parameters or entire model structures to capitalize on high-resolution data and context-specific model formulations. Data and methods contributed by the research community become part of a growing knowledge base, enabling faster and better ES assessment for users worldwide. By engaging with the ES modeling community to further develop and customize these models based on user needs, spatiotemporal contexts, and scale(s) of analysis, we aim to cover the full arc from simple to complex assessments, minimizing the additional cost to the user when increased complexity and accuracy are needed.
Spatial variation of carbon and nutrients stocks in Amazonian Dark Earth
Brazao Vieira Alho, C.F. ; Samuel Rosa, A. ; Coimbra Martins, Gilvan ; Hiemstra, T. ; Kuijper, T.W.M. ; Teixeira, Wenceslau G. - \ 2019
Geoderma 337 (2019). - ISSN 0016-7061 - p. 322 - 332.
Amazonian Dark Earths (ADE) are anthropic soils that are enriched in carbon (C) and several nutrients, particularly calcium (Ca) and phosphorus (P), when compared to adjacent soils from the Amazon basin. Studies on ADE empower the understanding of complex pre-Columbian cultural development in the Amazon and may also provide insights for future sustainable agricultural practices in the tropics. ADE are highly variable in size, depth and soil physico-chemical characteristics. Nonetheless, the differentiation between ADE and the adjacent soils is not standardized and is commonly done based on visual field observations. In this regard, the pretic horizon has been recently proposed as an attempt to classify ADE systematically. Spatial modelling techniques can be of great use to study the structure of the spatial variation of soil properties in highly variable areas. Here, we predicted the carbon and nutrients stocks in ADE by applying spatial modelling techniques using an environmental covariate (i.e. expected anthropic enrichment gradient) in our model. In addition, we used the pretic horizon criteria to classify pretic and non-pretic areas and evaluate their relative contribution to the total stocks. In this study, we collected soil samples from five 20-cm soil layers at n = 53 georeferenced points placed in a grid of about 10 to 60 m spacing in a study area located in Central Amazon (~9.4 ha). Ceramic fragments were weighed and quantified. Samples were analysed for: Total C, Total Ca, Total P, Exchangeable Ca + Mg, Extractable P, soil pH, potential CEC (pH = 7.0) and the clay content. The use of the pretic horizon criteria allowed us to clearly distinguish two unambiguous areas with a sharp transition, rather than a smooth continuum, in contrast to previous studies in ADE. Depth- and profile-wise linear regression model parameters indicated a greater importance of the chosen environmental covariate (i.e. expected anthropic enrichment gradient) to explain the spatial variation of Total Ca and Total P stocks than Total C stocks. The overall Total Ca and Total P stocks were twice as large in the pretic area when compared to the non-pretic area.
Exploring optimal catch crops for reducing nitrate leaching in vegetable greenhouse in North China
Zhang, Hongyuan ; Hu, Kelin ; Zhang, Lijuan ; Ji, Yanzhi ; Qin, Wei - \ 2019
Agricultural Water Management 212 (2019). - ISSN 0378-3774 - p. 273 - 282.
Catch crop - Greenhouse vegetable field - N uptake - Nitrate leaching - Soil-crop system model

Chinese intensive greenhouse vegetable systems are characterized by high input of water and nutrients, which are not sustainable. There is an urgent need to explore smart and practical strategies to convert the “high input-low output” systems to “optimal input-output” ones. This study aimed to evaluate the effects of different catch crops on reducing nitrate leaching in the vegetable greenhouse during the summer fallow season. A two-year field experiment with three catch crops, i.e., sweet corn (SC), amaranth (A) and sweet sorghum (SG), and no catch crop (CK) were conducted in vegetable greenhouse in Dingzhou city, Hebei province, China. The measured soil water content and inorganic nitrogen (N) content in soil profile, biomass and crop N uptake were used to validate the WHCNS (Soil Water Heat Carbon Nitrogen Simulator) model, soil water movement and nitrate leaching were simulated. The results showed that the catch crops decreased the water drainage by 18.2–29.0% and nitrate leaching by 23.3–42.3% respectively, compared with CK. The water drainage reduction ranked as SC > SG > A, while the nitrate leaching reduction was A > SC > SG. The biomass was SC > SG > A, while the crop N uptake was SC > A > SG. Sweet corn could absorb the residual nitrate in the deep soil layers due to the long root system, while amaranth could absorb most residual nitrate in the surface soil. Amaranth showed greater N-uptake capacity than sweet corn, and the nitrate was mainly accumulated in the surface soil. Planting amaranth as summer catch crop reduced nitrate leaching in the vegetable greenhouses. Our study provides a guideline for selecting effective catch crops in intensive vegetable greenhouses in North China.

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

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

Self-assembly of ellipsoidal particles at fluid-fluid interfaces with an empirical pair potential
Luo, Alan M. ; Vermant, Jan ; Ilg, Patrick ; Zhang, Zhenkun ; Sagis, Leonard M.C. - \ 2019
Journal of Colloid and Interface Science 534 (2019). - ISSN 0021-9797 - p. 205 - 214.
Capillary interactions - Ellipsoidal particles - Empirical pair potential - Fluid-fluid interfaces - Self-assembly

Colloidal particles adsorbed at fluid-fluid interfaces interact via mechanisms that can be specific to the presence of interfaces, for instance, lateral capillary interactions induced by nonspherical particles. Capillary interactions are highly relevant for self-assembly and the formation of surface microstructures, however, these are very challenging to model due to the multibody nature of capillary interactions. This work pursues a direct comparison between our computational modelling approach and experimental results on surface microstructures formed by ellipsoidal particles. We begin by investigating the accuracy of using pairwise interactions to describe the multibody capillary interaction by contrasting exact two- and three-particle interaction energies and we find that the pairwise approximation appears reasonable for the experimentally relevant configurations studied. We then develop an empirical pair potential and use it in Monte-Carlo type simulations to efficiently model the structure formation process for relevant particle properties such as aspect ratio, contact angle and surface coverage, and succeed in reproducing our experimental observations where we spread sterically-stabilised ellipsoidal particles onto an oil-air interface at high surface coverage. At lower surface coverages, we find that the self-assembly process falls into the diffusion-limited colloid aggregation universality class.

The effects of carbon dioxide on growth performance, welfare, and health of Atlantic salmon post-smolt (Salmo salar) in recirculating aquaculture systems
Mota, Vasco C. ; Nilsen, Tom Ole ; Gerwins, Jascha ; Gallo, Michele ; Ytteborg, Elisabeth ; Baeverfjord, Grete ; Kolarevic, Jelena ; Summerfelt, Steven T. ; Terjesen, Bendik Fyhn - \ 2019
Aquaculture 498 (2019). - ISSN 0044-8486 - p. 578 - 586.
Closed systems - CO - Hypercapnia - RAS - Salmonids

High carbon dioxide (CO2) concentrations negatively impact fish, which makes data on its tolerance especially relevant for production systems that can accumulate CO2 such as recirculating aquaculture system (RAS). The current study evaluates the effect of CO2 on the growth performance, welfare, and health of Atlantic salmon post-smolts in RAS. This study consisted of two phases. The first was a CO2 exposure phase, where eighteen tanks were used with six treatments in triplicate: 5, 12, 19, 26, 33 and 40 mg/L of CO2 during 12 weeks in a 12 ppt salinity RAS (hereafter RAS phase). In the second phase, PIT-tagged fish were transferred to a 34 ppt salinity single flow-through tank at CO2 < 5 mg/L (hereafter seawater phase) for an additional 6-week experimental period mimicking a seawater phase. Overall, mortality of fish exposed to CO2 was low and not related to treatments. The mean final body weight was significantly higher in the 5 mg/L treatment compared to CO2 treatments ≥12 mg/L at the end of RAS phase and to CO2 treatments ≥33 mg/L at the end of seawater phase. Moreover, regressions showed that growth significantly decreased linearly with increasing CO2 in the water. Eye cataracts and visible external damage on skin, operculum, and fins were inexistent and similar among CO2 treatments. Kidneys showed no signs of mineral deposits in any of the structures of the tissue. However, skin analysis showed that fish exposed to high CO2 concentrations had a significantly thinner dermis layer (both at the end of RAS and seawater phase) and a significantly thinner epidermis layer and lower mucus cells count (at the end of seawater phase). In conclusion, Atlantic salmon post-smolts cultured in brackish water RAS showed a maximum growth performance at CO2 concentrations below 12 mg/L. Except skin, no major effects of health and welfare were observed, including cataracts and nephrocalcinosis. Further studies should evaluate the molecular and physiological responses to both short-term and long-term carbon dioxide exposure.

Hatching failure and accumulation of organic pollutants through the terrestrial food web of a declining songbird in Western Europe
Oosten, H.H. van; Burg, Arnold B. van den; Arlt, Debora ; Both, Christiaan ; Brink, Nico W. van den; Chiu, Suzanne ; Crump, Doug ; Jeppsson, Tobias ; Kroon, Hans de; Traag, Wim ; Siepel, Henk - \ 2019
Science of the Total Environment 650 (2019). - ISSN 0048-9697 - p. 1547 - 1553.
Dioxin - DLC - Embryo - Inbreeding - Malformation - Passerine

Population growth in passerine birds is largely driven by fecundity. If fecundity is affected, for instance by hatching failure, populations may decline. We noted high hatching failure of up to 27% per year in relict populations of the Northern wheatear (Oenanthe oenanthe) in The Netherlands, a strongly declining, migratory passerine in Europe. This hatching failure itself can cause population decline, irrespective of other adverse factors. Additionally, we investigated the cause of hatching failure. Unhatched eggs showed egg yolk infections or embryonic malformations, part of which is associated with the actions of dioxin-like compounds (DLCs). Indeed, DLCs appear to bioaccumulate in the local foodweb, where the soil contained only background concentrations, similar to those found at many other locations. DLC concentrations in Dutch eggs were six-fold higher than those in a reference population in Sweden, where egg failure was only 6%. However, Northern wheatears appear to be only moderately sensitive to the actions of DLCs, because of their specific Ah-receptor type which may moderate the receptor mediated effects of DLCs. This indicates that the concentrations of DLCs, although elevated, may not have caused the embryo malformations or the low hatching rates. We discuss whether other toxins may be important or imbalances in the nutrition and if inbreeding may play a larger role than expected.

Influence of synthesis method on molybdenum carbide crystal structure and catalytic performance in stearic acid hydrodeoxygenation
Souza Macedo, Luana ; Oliveira, Ricardo R. ; Haasterecht, Tomas van; Teixeira da Silva, Victor ; Bitter, Harry - \ 2019
Applied Catalysis B-Environmental 241 (2019). - ISSN 0926-3373 - p. 81 - 88.
Crystal structure - Hydrodeoxygenation - Molybdenum carbide - Site density - Synthesis method

The role of the synthesis method of molybdenum carbide nanoparticle catalysts supported on carbon nanofibers on crystal structure and on catalytic performance in hydrodeoxygenation of stearic acid was investigated. We obtained the cubic phase of molybdenum carbide (α-MoC1-x) by impregnating carbon nanofibers with a solution of (NH4)2MoO4, then exposing them to 20% CH4/H2 at 650 °C for 2 h. When increasing the Mo loading from 7.5 wt% to 20 wt% or using the carbothermal reduction method, i.e. using carbon from the support to reduce the (NH4)2MoO4 precursor at 800 °C for 6 h, the hexagonal phase (β-Mo2C) resulted. Experiments with stearic acid hydrodeoxygenation showed that both phases (7.5 wt% Mo) displayed similar intrinsic activities. However, α-MoC1-x/CNF reached 80% stearic acid conversion after 240 min while the β-Mo2C/CNF catalyst attained the same conversion after 360 min. CO chemisorption results showed that α-MoC1-x/CNF and β-Mo2C/CNF have a similar number of potential active sites (66 and 56 μmol g−1, respectively). We attribute the difference in catalytic performance between α-MoC1-x/CNF and β-Mo2C/CNF to differences in the catalyst's crystal structure, more specifically, the associated site density. The face-centered cubic α-MoC1-x/CNF has a lower site density (0.1096 Mo atoms Ų) than the hexagonal close-packed β-Mo2C/CNF (0.1402 Mo atoms Ų), making the Mo atoms at the surface of the α-MoC1-x phase more accessible for large reactant molecules such as stearic acid thus allowing its convertion in shorter times.

Agricultural nitrogen and phosphorus emissions to water and their mitigation options in the Haihe Basin, China
Zhao, Zhanqing ; Qin, Wei ; Bai, Zhaohai ; Ma, Lin - \ 2019
Agricultural Water Management 212 (2019). - ISSN 0378-3774 - p. 262 - 272.
Crop-livestock system - Haihe Basin - Nitrogen - NUFER - Phosphorus - Water pollution

Agricultural nitrogen (N) and phosphorus (P) emissions to water bodies remain largely unknown in China, mainly due to the lack of reliable data sources and quantification tools. In this study, we constructed a grid-based NUFER (NUtrient Flow in food chains, Environment and Resources use) model in order to quantify a high-resolution agricultural N and P emissions to water bodies in Haihe Basin in 2012, based on data collected from county-level statistics, farm interview, and spatial data of topography, climate, soil texture, and land use. We also explored the mitigation strategies in 2030 via scenario analysis. The results showed that total agricultural N emission to water bodies in Haihe Basin was 1079 Gg N in 2012, of which cropland contributed 54%; total agricultural P emission to water bodies was 208 Gg P, livestock contributed 78%. There were large spatial variations in agricultural N and P emissions. Overall, the plain areas accounted for around 80% of the total agricultural N and P emissions to water in 2012. The highest N and P emission intensities were 10 t N km−2 and 2 t P km−2, respectively. N and P emissions were significantly related to anthropogenic factors (such as the livestock density and cropland) in the plain areas; whereas in mountainous areas, both anthropogenic and natural factors (e.g., slope deviation and soil texture) significantly affected N and P emissions. Our scenario analysis suggests that agricultural N and P emissions can be reduced by up to 45% and 77%, respectively for N and P in 2030, via improved agricultural and environmental policies, technologies and managements. The prohibition of direct animal manure discharge to the water system seems to be the most effective measure to mitigate the emissions. Our study provided a high-resolution agricultural N and P emissions to the water bodies of Haihe Basin and identified the most effective options to reduce these emissions in highly intensified agricultural areas.

Research idea to science for impact : Tracing the significant moments in an innovation based irrigation study
Srinivasan, M.S. ; Jongmans, C. ; Bewsell, D. ; Elley, G. - \ 2019
Agricultural Water Management 212 (2019). - ISSN 0378-3774 - p. 181 - 192.
Co-innovation - Co-learning - Irrigation - Stakeholder management - Weather forecast

Uptake of irrigation scheduling tools by New Zealand (NZ) farmers has remained static for many years and some researchers consider the use of linear, tech-transfer approaches as the main reason for this. To understand the controls and drivers that influence the uptake of these tools and to evaluate the effectiveness of a co-innovation approach in improving their (tools) uptake, a team of biophysical (hydrologists) and social researchers undertook a pilot study in an irrigation scheme in the South Island of NZ. Co-innovation offers a multi-directional, multi-level, multi-actor approach, in which input from stakeholders is valued in every part of the process, from problem definition to solution adoption. In this study, we focused on the adaptive aspect of co-innovation that allows stakeholders to periodically review their actions and respond to it in a way that is inclusive others’ views and reflective of feedback received. The pilot study activities were analysed retrospectively to develop a systemic view to the implementation of a co-innovation-based multi-stakeholder hydrology project. While implementing a co-innovation approach, five chronologically-distinct yet overlapping phases emerged in the project: 1. concept development, where the hydrologists came up with the research idea and seed concept; 2. trust building, where researchers (hydrologists and social) interacted with key on-farm stakeholders in developing and implementing the research idea into a pilot field study; 3. knowledge synthesis, where researchers collected on-farm biophysical and behavioural data to record practice change; 4. extended outreach, where stakeholders, including researchers, devised pathways to sustain the lessons learned and practices changed, and disseminated the learnings to the wider irrigation community; and 5. project legacy, where the researchers, after the development of the seed concept into a practice change, evolved an exit strategy. Apart from core research activities, such as data collection on irrigation water use and changes in irrigation scheduling practices, each one of the five phases included actions that were unique to that phase as well as to achieving the wider pilot study goal of improving water use efficiency. This paper discusses the learnings from these phases, including insights, and key identifiers and indicators of pilot study progression during each phase, which may serve as an example to other biophysical studies that propose to employ co-innovation-based multi stakeholder approach.

An accurate evaluation of water availability in sub-arid Mediterranean watersheds through SWAT : Cega-Eresma-Adaja
Rivas-Tabares, David ; Tarquis, Ana M. ; Willaarts, Bárbara ; Miguel, Ángel De - \ 2019
Agricultural Water Management 212 (2019). - ISSN 0378-3774 - p. 211 - 225.
Land use - Modelling - Semi-arid regions - Streamflow - SWAT

Simulation of flow processes in hyper-regulated Mediterranean watersheds is critical when examining general water demand and established ecological flows of River Basin Management Plans. Weather dynamics in the Mediterranean zone in recent decades have been characterised by a natural variation of drought cycles. In addition, exacerbated climate change proves that water fluxes must be estimated with more exhaustive models. The aim of this study is to assess the water balance of the Cega-Eresma-Adaja (CEA) watershed, including a detailed assessment of land uses and management practices to quantify agricultural water demand for the time period 2004–2014. We used the Soil and Water Assessment Tool (SWAT), given that it is a widespread tool that involves complex processes of the water cycle on a basin scale, providing information on water dynamics related to land use as a fundamental characteristic for water balance calculation. The Nash-Sutcliffe coefficient efficiency value, the main index of calibration and validation performance, was 0.86 for the Eresma-Adaja River and 0.67 for the Cega River. This presents a good result considering the large-scale watershed studied. Analysing dry hydrological years, we found that the estimation of ecological flows for sub-arid zones needs to consider the shallow aquifer-river relationship. During spring-summer periods, with very low flow, monitoring the shallow aquifer levels ensures a good ecological status. The study reveals that aspects such as crop rotation, soil management and their associated measures in Mediterranean basins are key factors for water resource management during drought periods. These results are expected to serve stakeholders and river basin authorities in conducting better-integrated water management practices in the watershed.

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