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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    Evolution of drug-resistant and virulent small colonies in phenotypically diverse populations of the human fungal pathogen Candida glabrata
    Duxbury, Sarah J.N. ; Bates, Steven ; Beardmore, Robert E. ; Gudelj, Ivana - \ 2020
    Proceedings of the Royal Society. B: Biological Sciences 287 (2020)1931. - ISSN 0962-8452 - 9 p.
    drug resistance - fungal populations - growth rate - virulence

    Antimicrobial resistance frequently carries a fitness cost to a pathogen, measured as a reduction in growth rate compared to the sensitive wild-type, in the absence of antibiotics. Existing empirical evidence points to the following relationship between cost of resistance and virulence. If a resistant pathogen suffers a fitness cost in terms of reduced growth rate it commonly has lower virulence compared to the sensitive wild-type. If this cost is absent so is the reduction in virulence. Here we show, using experimental evolution of drug resistance in the fungal human pathogen Candida glabrata, that reduced growth rate of resistant strains need not result in reduced virulence. Phenotypically heterogeneous populations were evolved in parallel containing highly resistant sub-population small colony variants (SCVs) alongside sensitive sub-populations. Despite their low growth rate in the absence of an antifungal drug, the SCVs did not suffer a marked alteration in virulence compared with the wild-type ancestral strain, or their co-isolated sensitive strains. This contrasts with classical theory that assumes growth rate to positively correlate with virulence. Our work thus highlights the complexity of the relationship between resistance, basic life-history traits and virulence.

    Circular bio-based production systems in the context of current biomass and fossil demand
    Bos, Harriëtte L. ; Broeze, Jan - \ 2020
    Biofuels Bioproducts and Biorefining 14 (2020)2. - ISSN 1932-104X - p. 187 - 197.
    bio-based economy - biomass - circularity - fossil feedstock - resource use efficiency

    In this article we explore the quantitative challenges posed by the intended circular biobased economy. To do this, we present the relative sizes, in terms of mass and energy, of the agro-food and fossil production system, and the interrelations in the system of transformation to food, feed, materials, and energy. We deduce that the flows in the fossil system are of a comparable magnitude to the agricultural / biomass production in terms of mass and energy. This implies that replacing a significant fraction of fossil-derived products by biobased products will be a huge challenge. Solving this challenge will require both efficiency improvements and circular innovations. The analysis reveals major inefficiencies in the current system. In terms of mass, the pathways from agricultural production to food seem quite inefficient, on average less than 10%. This suggests space for efficiency improvement. The relatively low efficiency of livestock production confirms the relevance of diet change. Likewise, enhanced utilization of side streams appears significant. However, we show that in the current system of linear chains, such solutions are insufficient to provide an alternative to the current volume of fossil use. We argue that, next to biobased solutions, multifunctional use and recycling will be essential if we want to maintain current living standards and reduce dependence on fossil feedstock. We reflect on this consideration, and define four different cycles in the combined biomass / fossil system. These circles may be optimized and extended to improve the circularity of our carbon-based production systems and to fight climate change.

    Swimming Performance and Oxygen Consumption as Non-lethal Indicators of Production Traits in Atlantic Salmon and Gilthead Seabream
    Palstra, Arjan P. ; Kals, Jeroen ; Böhm, Thijs ; Bastiaansen, John W.M. ; Komen, Hans - \ 2020
    Frontiers in Physiology 11 (2020). - ISSN 1664-042X
    aquaculture - feed conversion ratio - metabolic rate - selective breeding - starvation-refeeding - swim-tunnel respirometry

    The aim of this study was to investigate swimming performance and oxygen consumption as non−lethal indicator traits of production parameters in Atlantic salmon Salmo salar L. and Gilthead seabream Sparus aurata L. A total of 34 individual fish of each species were subjected to a series of experiments: (1) a critical swimming speed (Ucrit) test in a swim-gutter, followed by (2) two starvation-refeeding periods of 42 days, and (3) swimming performance experiments coupled to respirometry in swim-tunnels. Ucrit was assessed first to test it as a predictor trait. Starvation-refeeding traits included body weight; feed conversion ratio based on dry matter; residual feed intake; average daily weight gain and loss. Swim-tunnel respirometry provided oxygen consumption in rest and while swimming at the different speeds, optimal swim speed and minimal cost of transport (COT). After experiments, fish were dissected and measured for tissue weights and body composition in terms of dry matter, ash, fat, protein and moist, and energy content. The Ucrit test design was able to provide individual Ucrit values in high throughput manner. The residual Ucrit (RUcrit) should be considered in order to remove the size dependency of swimming performance. Most importantly, RUcrit predicted filet yield in both species. The minimal COT, the oxygen consumption when swimming at Uopt, added predictive value to the seabream model for feed intake.

    Coupling 3D Printing and Novel Replica Molding for In House Fabrication of Skeletal Muscle Tissue Engineering Devices
    Iuliano, Alessandro ; Wal, Erik van der; Ruijmbeek, Claudine W.B. ; ‘t Groen, Stijn L.M. in; Pijnappel, Pim ; Greef, Jessica C. de; Saggiomo, Vittorio - \ 2020
    Advanced Materials Technologies (2020).
    3D printing - hiPSCs - replica molding - skeletal muscles - tissue engineering

    The transition from 2D to 3D engineered tissue cultures is changing the way biologists can perform in vitro functional studies. However, there has been a paucity in the establishment of methods required for the generation of microdevices and cost-effective scaling up. To date, approaches including multistep photolithography, milling and 3D printing have been used that involve specialized and expensive equipment or time-consuming steps with variable success. Here, a fabrication pipeline is presented based on affordable off-the-shelf 3D printers and novel replica molding strategies for rapid and easy in-house production of hundreds of 3D culture devices per day, with customizable size and geometry. This pipeline is applied to generate tissue engineered skeletal muscles in vitro using human induced pluripotent stem cell-derived myogenic progenitors. These production methods can be employed in any standard biomedical laboratory.

    Bioprospecting and characterization of temperature tolerant microalgae from Bonaire
    Barten, Robin J.P. ; Wijffels, Rene H. ; Barbosa, Maria J. - \ 2020
    Algal Research 50 (2020). - ISSN 2211-9264
    Biomass composition - Bioprospecting - Fatty acids - Growth rate - Microalgae - Thermo-tolerant

    Control of temperature is a major challenge for industrial microalgae production in photobioreactors outdoors. Strains with tolerance for high temperatures can reduce the cost of production as active temperature control is not required. In this study, marine photoautotrophic microorganisms were isolated to reduce the need for control of high temperature. Twenty-two samples were taken from different saline waters on the Caribbean island Bonaire. During strain enrichment, a temperature of 40 °C was used as selective pressure and strains with the highest growth rate were selected. We isolated and identified 59 strains, after which 5 were selected for characterization on growth rate and biomass composition. Picochlorum sp. and Leptolyngbya sp. showed optimal growth at 40 °C and 35 °C with a growth rate of 0.12 h−1 during daytime, respectively. The strains contain 62.1% and 68.2% of protein and have varying fatty acid compositions suitable for application as edible oil and biofuel.

    Cephalopod-Inspired High Dynamic Range Mechano-Imaging in Polymeric Materials
    Clough, Jess M. ; Gucht, Jasper van der; Kodger, Thomas E. ; Sprakel, Joris - \ 2020
    Advanced Functional Materials (2020). - ISSN 1616-301X
    colloids - mechanochemistry - mechanochromism - photonics - polymers

    Cephalopods, such as squid, cuttlefish, and octopuses, use an array of responsive absorptive and photonic dermal structures to achieve rapid and reversible color changes for spectacular camouflage and signaling displays. Challenges remain in designing synthetic soft materials with similar multiple and dynamic responsivity for the development of optical sensors for the sensitive detection of mechanical stresses and strains. Here, a high dynamic range mechano-imaging (HDR-MI) polymeric material integrating physical and chemical mechanochromism is designed providing a continuous optical read-out of strain upon mechanical deformation. By combining a colloidal photonic array with a mechanically responsive dye, the material architecture significantly improves the mechanochromic sensitivity, which is moreover readily tuned, and expands the range of detectable strains and stresses at both microscopic and nanoscopic length scales. This multi-functional material is highlighted by creating detailed HDR mechanographs of membrane deformation and around defects using a low-cost hyperspectral camera, which is found to be in excellent agreement with the results of finite element simulations. This multi-scale approach to mechano-sensing and -imaging provides a platform to develop mechanochromic composites with high sensitivity and high dynamic mechanical range.

    Selective separation of flavour-active compounds from strip gas using frictional diffusion
    Ammari, Ali ; Schroën, Karin G.P.H. ; Boom, Remko M. - \ 2020
    Separation and Purification Technology 251 (2020). - ISSN 1383-5866
    Beer - Flavour separation - Frictional diffusion - Gas-phase

    Attaining constant flavour composition in products that are produced batch-wise, such as beer, is not trivial given the inherent variability in fermentation. CO2 stripping is feasible but unselective. Condensation of the flavour is possible but energy intensive. We here propose the use of frictional diffusion (also called FricDiff), which is based on differences in diffusion rates in a sweep or carrier gas such as CO2 through an inert porous medium. Application of a slight counter-flow of the sweep gas can be used to adapt the selectivity between different flavours. It is shown that from a difference in diffusion rate of 25%, a selectivity of more than 10 can be obtained between ethyl acetate and isoamyl acetate, albeit at the cost of the flavour flux through the porous barrier.

    Should we reinforce the grid? Cost and emission optimization of electric vehicle charging under different transformer limits
    Brinkel, N.B.G. ; Schram, W.L. ; AlSkaif, T.A. ; Lampropoulos, I. ; Sark, W.G.J.H.M. van - \ 2020
    Applied Energy 276 (2020). - ISSN 0306-2619
    Average & marginal emission profiles - Battery degradation - Electric vehicle smart charging - Grid reinforcements - Multi-objective optimization - Vehicle-to-grid

    With high electric vehicle (EV) adoption, optimization of the charging process of EVs is becoming increasingly important. Although the CO2 emission impact of EVs is heavily dependent on the generation mix at the moment of charging, emission minimization of EV charging receives limited attention. Generally, studies neglect the fact that cost and emission savings potential for EV charging can be constrained by the capacity limits of the low-voltage (LV) grid. Grid reinforcements provide EVs more freedom in minimizing charging costs and/or emissions, but also result in additional costs and emissions due to reinforcement of the grid. The first aim of this study is to present the trade-off between cost and emission minimization of EV charging. Second, to compare the costs and emissions of grid reinforcements with the potential cost and emission benefits of EV charging with grid reinforcements. This study proposes a method for multi-objective optimization of EV charging costs and/or emissions at low computational costs by aggregating individual EV batteries characteristics in a single EV charging model, considering vehicle-to-grid (V2G), EV battery degradation and the transformer capacity. The proposed method is applied to a case study grid in Utrecht, the Netherlands, using highly-detailed EV charging transaction data as input. The results of the analysis indicate that even when considering the current transformer capacity, cost savings up to 32.4% compared to uncontrolled EV charging are possible when using V2G. Emission minimization can reduce emissions by 23.6% while simultaneously reducing EV charging costs by 13.2%. This study also shows that in most cases, the extra cost or emission benefits of EV charging under a higher transformer capacity limit do not outweigh the cost and emissions for upgrading that transformer.

    Effects of input vouchers and rainfall insurance on agricultural production and household welfare: Experimental evidence from northern Ethiopia
    Wong, H.L. ; Wei, X. ; Kahsay, H.B. ; Gebreegziabher, Z. ; Gardebroek, C. ; Osgood, D.E. ; Diro, R. - \ 2020
    World Development 135 (2020). - ISSN 0305-750X - 17 p.
    Agricultural input vouchers - Rainfall index insurance - Agricultural production - Randomized controlled trial - Productive Safety Net Programme - Rural Ethiopia
    We report on a randomized field experiment designed to relax credit and risk constraints for agricultural activities. We conducted a study in a drought-prone region in northern Ethiopia among poor smallholders who depended on rainfed agriculture and were members of the Productive Safety Net Programme (PSNP).
    Data were collected from over 1100 farmers in 32 rural villages over two years. We find that unconditional voucher transfers designated for the purchase of agricultural inputs significantly increased usage of seeds and fertilizers (a flypaper effect), raised the amount of farmland used (a complementary effect), and induced substitution of own effort by hiring casual labor (a local spillover effect). Subsidized rainfall insurance with reduced input vouchers produced weak average effects but greatly increased investments for farmers who were relatively more patient. We do not find heterogeneous effects by farmers’ risk attitudes, however, suggesting that the effects of insurance adoption were mainly determined by how farmers in the safety net made trade-offs inter-temporally. Insurance demand dropped quickly with the reduction in subsidy and did not correlate with time or risk preference. Therefore, to improve cost-effectiveness, insurance programs should include procedures that help identify forward-looking farmers and encourage their adoption. While our results show that initial subsidies increase future insurance demand, the effect was small and thus initial
    subsidies would not be a cost-effective mechanism for financially sustainable insurance. Other complementary strategies on the design, promotion, and bundling techniques of insurance would be needed.
    An efficient single-cell transcriptomics workflow for microbial eukaryotes benchmarked on Giardia intestinalis cells
    Onsbring, Henning ; Tice, Alexander K. ; Barton, Brandon T. ; Brown, Matthew W. ; Ettema, Thijs J.G. - \ 2020
    BMC Genomics 21 (2020)1. - ISSN 1471-2164 - 1 p.
    Giardia intestinalis - Microbial diversity - Microbial eukaryotes - Protists - RNAseq - Single cell genomics - Single-cell RNA sequencing - Smart-seq2 - Transcriptome - Transcriptomics

    BACKGROUND: Most diversity in the eukaryotic tree of life is represented by microbial eukaryotes, which is a polyphyletic group also referred to as protists. Among the protists, currently sequenced genomes and transcriptomes give a biased view of the actual diversity. This biased view is partly caused by the scientific community, which has prioritized certain microbes of biomedical and agricultural importance. Additionally, some protists remain difficult to maintain in cultures, which further influences what has been studied. It is now possible to bypass the time-consuming process of cultivation and directly analyze the gene content of single protist cells. Single-cell genomics was used in the first experiments where individual protists cells were genomically explored. Unfortunately, single-cell genomics for protists is often associated with low genome recovery and the assembly process can be complicated because of repetitive intergenic regions. Sequencing repetitive sequences can be avoided if single-cell transcriptomics is used, which only targets the part of the genome that is transcribed. RESULTS: In this study we test different modifications of Smart-seq2, a single-cell RNA sequencing protocol originally developed for mammalian cells, to establish a robust and more cost-efficient workflow for protists. The diplomonad Giardia intestinalis was used in all experiments and the available genome for this species allowed us to benchmark our results. We could observe increased transcript recovery when freeze-thaw cycles were added as an extra step to the Smart-seq2 protocol. Further we reduced the reaction volume and purified the amplified cDNA with alternative beads to test different cost-reducing changes of Smart-seq2. Neither improved the procedure, and reducing the volumes by half led to significantly fewer genes detected. We also added a 5' biotin modification to our primers and reduced the concentration of oligo-dT, to potentially reduce generation of artifacts. Except adding freeze-thaw cycles and reducing the volume, no other modifications lead to a significant change in gene detection. Therefore, we suggest adding freeze-thaw cycles to Smart-seq2 when working with protists and further consider our other modification described to improve cost and time-efficiency. CONCLUSIONS: The presented single-cell RNA sequencing workflow represents an efficient method to explore the diversity and cell biology of individual protist cells.

    Social learning and land lease to stimulate the delivery of ecosystem services in intensive arable farming
    Westerink, Judith ; Pérez-Soba, Marta ; Doorn, Anne van - \ 2020
    Ecosystem Services 44 (2020). - ISSN 2212-0416
    Behaviour - Ecosystem services - Farmer groups - Governance arrangements - Private - Social learning

    Current intensive arable production systems tend to favour food production at the cost of the provision of other ecosystem services. In order to decrease the environmental impact and increase the variety and level of ecosystem services delivery, arable farmers would need to change their current practices. Governance arrangements aimed at such changes of behaviour not only include those from government, but also from institutions as developed bottom-up by farmers, other actors and networks. This paper investigates the role that governance arrangements developed by groups of farmers in intensive arable production systems in The Netherlands may have in changing agronomic practices that will improve the delivery of regulating and cultural ecosystem services. We evaluate the arrangements according to their potential effects on farmers and their social environment. Firstly, we consider the effect on farmers’ motivation and ability to change their practices. And secondly we consider the legitimation of, and demand for behavioural change by their social environment. The results suggest that social learning and land lease are promising supportive governance arrangements for behavioural change, and that private and public governance arrangements can be complementary.

    The effective design of sampling campaigns for emerging chemical and microbial contaminants in drinking water and its resources based on literature mining
    Hartmann, Julia ; Driezum, Inge van; Ohana, Dana ; Lynch, Gretta ; Berendsen, Bjorn ; Wuijts, Susanne ; Hoek, Jan Peter van der; Roda Husman, Ana Maria de - \ 2020
    Science of the Total Environment 742 (2020). - ISSN 0048-9697
    Contaminants - Early warning - Emerging - Pathogen

    As well as known contaminants, surface waters also contain an unknown variety of chemical and microbial contaminants which can pose a risk to humans if surface water is used for the production of drinking water. To protect human health proactively, and in a cost-efficient way, water authorities and drinking water companies need early warning systems. This study aimed to (1) assess the effectiveness of screening the scientific literature to direct sampling campaigns for early warning purposes, and (2) detect new aquatic contaminants of concern to public health in the Netherlands. By screening the scientific literature, six example contaminants (3 chemical and 3 microbial) were selected as potential aquatic contaminants of concern to the quality of Dutch drinking water. Stakeholders from the Dutch water sector and various information sources were consulted to identify the potential sources of these contaminants. Based on these potential contamination sources, two sampling sequences were set up from contamination sources (municipal and industrial wastewater treatment plants), via surface water used for the production of drinking water to treated drinking water. The chemical contaminants, mycophenolic acid, tetrabutylphosphonium compounds and Hexafluoropropylene Oxide Trimer Acid, were detected in low concentrations and were thus not expected to pose a risk to Dutch drinking water. Colistin resistant Escherichia coli was detected for the first time in Dutch wastewater not influenced by hospital wastewater, indicating circulation of bacteria resistant to this last-resort antibiotic in the open Dutch population. Four out of six contaminants were thus detected in surface or wastewater samples, which showed that screening the scientific literature to direct sampling campaigns for both microbial and chemical contaminants is effective for early warning purposes.

    The mechanism and application of bidirectional extracellular electron transport in the field of energy and environment
    Xie, Qingqing ; Lu, Yue ; Tang, Lin ; Zeng, Guangming ; Yang, Zhaohui ; Fan, Changzheng ; Wang, Jingjing ; Atashgahi, Siavash - \ 2020
    Critical Reviews in Environmental Science and Technology (2020). - ISSN 1064-3389
    Bioremediation - energy production - extracellular electron transfer

    Bidirectional extracellular electron transfer (EET) is mediated by back and forth electron delivery between microorganisms and extracellular substances. This enables the exchange of biochemical information and energy with the surrounding environments. As a novel bioenergy strategy, bidirectional EET provides low-cost opportunities for the production of clean energy sources and carriers (e.g., hydrogen and methane) as well as the production of value-added chemicals from carbon dioxide. Electrochemically active bacteria (EAB) can also transform pollutants to less toxic or benign substances in contaminated environments, and therefore they have been widely applied in bioremediation studies. Among all the available EAB, Geobacter and Shewanella are well-known for their versatility to accept/donate electrons from/to external environments. In this review, we focus on how these model EAB generate or harvest energy through bidirectional EET, as well as recent advances in the application of EET in bioelectrochemical technology and environmental bioremediation. Finally, the challenges, perspectives and new directions in the bidirectional EET studies are discussed. (Figure presented.).

    Harnessing biodegradation potential of rapid sand filtration for organic micropollutant removal from drinking water : A review
    Wang, Jinsong ; Ridder, David de; Wal, Albert van der; Sutton, Nora B. - \ 2020
    Critical Reviews in Environmental Science and Technology (2020). - ISSN 1064-3389 - 33 p.
    bioaugmentation - drinking water - Organic micropollutants biodegradation - rapid sand filtration

    A cost-effective approach for efficient organic micropollutants (OMPs) removal is to optimize existing infrastructure at drinking water treatment plants. A promising option is rapid sand filtration (RSF), as OMPs removal has been observed in this treatment technology. However, the mechanisms and pathways involved are not fully understood and strategies to optimize removal have yet to be thoroughly explored. Therefore, this article firstly described basic RSF functions that can support OMPs removal. OMPs can be removed by chemical and biological Mn/Fe oxides or degraded co-metabolically by ammonia oxidizing bacteria and methane oxidizing bacteria. In addition, heterotrophic bacteria can metabolically transform OMPs and their transformation products. Then, we reviewed current literatures described OMPs removal in RSF, showing biodegradation can contribute significantly to OMPs removal. Thereafter, we presented strategies to improve OMPs biodegradation, including bioaugmentation, optimizing hydraulic conditions by adjusting contact time and backwashing intensity, and adding biocarriers to retain biomass during rapid flow rates. Finally, we provided recommendations for further research towards optimizing and maintaining OMPs removal in RSF for safe drinking water production. This review therefore gives a critical evaluation of RSF-based technologies for OMPs removal from drinking water and provides recommendations for further improving OMPs removal in RSF.

    Refer logistics and cold chain transport : A systematic review and multi-actor system analysis of an un-explored domain
    Fan, Yun ; Behdani, Behzad ; Bloemhof-Ruwaard, Jacqueline M. - \ 2020
    European Journal of Transport and Infrastructure Research 20 (2020)2. - ISSN 1567-7141 - p. 1 - 35.
    Cold chain management - Multi-actor setting - Reefer logistics - Review - System analysis

    Reefer logistics is an important part of the cold chain in which reefer containers are involved as the packaging for transporting perishable goods. Reefer logistics is challenging, as it deals with cost and time constraints as well as the product quality and sustainability requirements. In many situations, there is a trade-off between these factors (e.g., between transportation cost and the quality of fresh products). Furthermore, considering the high value of reefers, the efficient logistics of reefers is as important as the efficient cargo flows. This causes technical complications and the conflicts of interests between actors, especially, between cargo owners (or shippers) and the asset owners (or transport/terminal operators). Improving the efficiency of reefer logistics calls for a thorough understanding of the trade-offs and complexities. This paper aims to help develop such an understanding using a systematic literature review and a socio-technical system analysis. The results can be used to provide managerial insights for actors involved in a cold chain to design tailored solutions for reefers.

    Development of a QSAR model to predict hepatic steatosis using freely available machine learning tools
    Cotterill, J. ; Price, N. ; Rorije, E. ; Peijnenburg, A. - \ 2020
    Food and Chemical Toxicology 142 (2020). - ISSN 0278-6915
    Non-alcoholic fatty liver disease - QSAR model - Steatosis

    There are various types of hepatic steatosis of which non-alcoholic fatty liver disease, which may be caused by exposure to chemicals and environmental pollutants is the most prevalent, representing a potential major health risk. QSAR modelling has the potential to provide a rapid and cost-effective method to identify compounds which may trigger steatosis. Although models exist to predict key molecular initiating events of steatosis such as nuclear receptor binding, we are aware of no models to predict the apical effect steatosis. In this study, we describe the development of a QSAR model to predict steatosis using freely available machine learning tools. It was built using a dataset of 207 pharmaceuticals and pesticides which were identified as steatotic or non-steatotic from existing data from in vivo human and animal studies. The best performing model developed using the linear discriminant analysis module in TANAGRA, based on four chemical descriptors, had an accuracy of 70%, a sensitivity of 66% and a specificity of 74%. The expansion of the steatosis dataset to other chemical types, to enable the development of further models, would be of benefit in the identification of compounds with a range of mechanisms of action contributing to steatosis.

    Fast room-temperature functionalization of silicon nanoparticles using alkyl silanols
    Boom, Alyssa F.J. van den; Pujari, Sidharam P. ; Bannani, Fatma ; Driss, Hafedh ; Zuilhof, Han - \ 2020
    Faraday Discussions 222 (2020). - ISSN 1359-6640 - p. 82 - 94.

    Silicon nanoparticles (Si NPs) are a good alternative to conventional heavy metal-containing quantum dots in many applications, due to their low toxicity, low cost, and the high natural abundance of the starting material. Recently, much synthetic progress has been made, and crystalline Si NPs can now be prepared in a matter of hours. However, the passivation of these particles is still a time-consuming and difficult process, usually requiring high temperatures and/or harsh reaction conditions. In this paper, we report an easy method for the room-temperature functionalization of hydrogen-terminated Si NPs. Using silanol compounds, a range of functionalized Si NPs could be produced in only 1 h reaction time at room temperature. The coated NPs were fully characterized to determine the efficiency of binding and the effects of coating on the optical properties of the NPs. It was found that Si NPs were effectively functionalized, and that coated NPs could be extracted from the reaction mixture in a straightforward manner. The silanol coating increases the quantum yield of fluorescence, decreases the spectral width and causes a small (∼50 nm) blue-shift in both the excitation and emission spectra of the Si NPs, compared to unfunctionalized particles.

    Costs and Carbon Benefits of Mangrove Conservation and Restoration : A Global Analysis
    Jakovac, Catarina C. ; Latawiec, Agnieszka Ewa ; Lacerda, Eduardo ; Leite Lucas, Isabella ; Korys, Katarzyna Anna ; Iribarrem, Alvaro ; Malaguti, Gustavo Abreu ; Turner, R.K. ; Luisetti, Tiziana ; Baeta Neves Strassburg, Bernardo - \ 2020
    Ecological Economics 176 (2020). - ISSN 0921-8009
    Break-even price - Deforestation - Global mangrove map - Land opportunity cost - Map of worlds - Payment for ecosystem services - REDD+

    Blue carbon in mangroves represents one of highest values of carbon stocks per hectare, and could play an important role in climate change mitigation. In this study we estimated the carbon prices needed to promote mangrove conservation and restoration under mechanisms of payment for ecosystem services (PES). We mapped the remaining and deforested mangroves across the globe in 2017, and crossed this information with carbon stocks in the biomass and soil and with land opportunity and restoration costs. In accordance with previous studies we found that Southeast Asia holds the largest opportunities for blue carbon programs to support conservation and restoration. Conserving remaining mangroves would avoid the release of up to 15.51 PgCO2 to the atmosphere, and could be achieved at carbon prices between 3.0 and 13.0 US$ per tCO2 for 90% of remaining mangroves. Restoring mangroves can sequester up to 0.32 PgCO2 globally. Carbon prices between 4.5 and 18.0 US$ per tCO2 could support the restoration of 90% of deforested mangroves. Such prices, however, may not apply to contexts of high-profit alternative land-uses. In such contexts, the valuation of co-benefits and the combination of carbon-based mechanisms and sustainable management may be a viable pathway.

    Dynamic Cost Inefficiency of the European Union Meat Processing Firms
    Kapelko, Magdalena ; Oude Lansink, A.G.J.M. - \ 2020
    Journal of Agricultural Economics (2020). - ISSN 0021-857X - 18 p.
    We apply dynamic data envelopment analysis (DEA) to estimate dynamic cost inefficiency for a sample of European Union (EU) large meat processing firms over the period 2005–2012 and decompose this into the contributions of technical and allocative inefficiency. The estimation of dynamic inefficiencies controls for adjustment costs associated with firms’ investments. We further contribute by measuring dynamic cost inefficiencies and their components with regard to own region group (managerial inefficiencies) and the gap between the pooled frontier and the region‐specific frontier (programme inefficiencies). Results show that technical inefficiency tends to be the largest component of cost inefficiency when both conducting the analysis for the EU as a whole and estimating a region‐specific frontier. Results suggest significant differences in cost, technical, and allocative inefficiencies between meat processing firms in eastern, western and southern EU countries. We also find that the gaps between the pooled and region‐specific frontiers tend to be small to negligible, which suggests that the main source of pooled inefficiencies are shortcomings in managerial practices rather than differences in region‐specific conditions.
    The nature and drivers of contracts in cattle herding and management : The case of Ghana
    Ameleke, Godwin Yao ; Haagsma, Rein ; Karbo, Naaminong ; Mensah-Bonsu, Akwasi - \ 2020
    Pastoralism: Research, Policy and Practice 10 (2020)1. - ISSN 2041-7136
    Africa - Agency theory - Cattle herding - Cattle production - Contract - Pastoralism - Transaction cost

    We study the characteristics of contracts in cattle production in Ghana and explain variations in contract type using agency and transaction cost theory. In their study of pastoral groups, especially those in West Africa, anthropologists have distinguished between two categories of contracts in cattle production: cattle owner–herd manager contracts and herd manager–herdsman contracts. However, few studies have analysed the variations in contract type within each category. Using survey data from 342 cattle kraal owners, we explored the contract types under the two contract categories and analysed their drivers using crosstabulations. Contract types in each category can be explicit, with the reward given by the principal explicitly specified, or implicit and unspecified. Environmental uncertainty was associated with implicit contracts while for explicit contracts, kraal owners’ outside options or opportunity cost for monitoring was associated with fixed-wage contracts, subsidy-only contracts, and input contribution by kraal owners. The combination of moral hazard and measurement costs explained whether herdsmen were familial and not paid with milk or hired and paid with milk. Our findings provide further insights into the drivers of contract type.

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