Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    '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.

    We have a manual that explains all the features 

Current refinement(s):

Records 1 - 20 / 410

  • help
  • print

    Print search results

  • export
    A maximum of 250 titles can be exported. Please, refine your queryYou can also select and export up to 30 titles via your marked list.
  • alert
    We will mail you new results for this query: keywords==system
Check title to add to marked list
Global animal production and nitrogen and phosphorus flows
Liu, Qian ; Wang, Jingmeng ; Bai, Zhaohai ; Ma, Lin ; Oenema, Oene - \ 2017
Soil Research 55 (2017)5-6. - ISSN 1838-675X - p. 451 - 462.
feed - livestock density - manure management - nitrogen balance - nitrogen use efficiency - phosphorus balance - phosphorus use efficiency - system
Animal production systems provide nutritious food for humans, income and survivability for numerous smallholder farms and transform residues to valuable products. However, animal production is implicated in human health issues (diet-related diseases, zoonosis, antimicrobial resistance) and environmental burdens (ammonia and greenhouse gas emissions, eutrophication of surface waters, biodiversity loss). This paper reviews changes in global animal production and associated nitrogen (N) and phosphorus (P) flows over the past 50 years, during which time total animal production roughly tripled. Cattle still dominate the world in terms of animal biomass, but the number and total production of pigs and poultry have increased faster. Animal production systems are highly diverse and respond to changes in markets. Specialised systems have become more dominant, especially in developed and rapidly developing countries. The annual production of N and P in manure is similar to the amounts of N and P in synthetic fertiliser produced annually, but manure nutrients are often not recycled effectively and used efficiently by plants. Nutrient losses greatly depend on the system, management and regulations. Nitrogen and P use efficiency (NUE and PUE respectively) at the animal level is in the range 5-45%, depending on animal category, feeding and management. NUE of mixed crop-animal systems may range from 5% to 65% depending on NUE at the animal level, and the utilisation of manure nitrogen and new nitrogen inputs. Potentially, values for PUE are higher than those for NUE. Solutions for improving NUE and PUE in animal production are based on a coherent set of activities in the whole chain of 'feed production-animal production-manure management'. A high efficiency at the system level is achieved through combination of high NUE and PUE at the animal level and effective recycling and utilisation of manure N and P in crop production. Specific regional regulations (low-emission manure storage and application, proper application limits and timing) greatly contribute to high efficiency at a system level.
Spanning the scales of granular materials through microscopic force imaging
Brodu, N. ; Dijksman, J.A. ; Behringer, R.P. - \ 2015
Nature Communications 6 (2015). - ISSN 2041-1723 - 6 p.
system - media
If you walk on sand, it supports your weight. How do the disordered forces between particles in sand organize, to keep you from sinking? This simple question is surprisingly difficult to answer experimentally: measuring forces in three dimensions, between deeply buried grains, is challenging. Here we describe experiments in which we have succeeded in measuring forces inside a granular packing subject to controlled deformations. We connect the measured micro-scale forces to the macro-scale packing force response with an averaging, mean field calculation. This calculation explains how the combination of packing structure and contact deformations produce the observed nontrivial mechanical response of the packing, revealing a surprising microscopic particle deformation enhancement mechanism.
Investigations into the biosynthesis, regulation, and self-resistance of toxoflavin in Pseudomonas protegens Pf-5
Philmus, B. ; Shaffer, B.T. ; Kidarsa, T.A. ; Yan, Q. ; Raaijmakers, J.M. ; Begley, T.P. ; Loper, J.E. - \ 2015
ChemBioChem 16 (2015)12. - ISSN 1439-4227 - p. 1782 - 1790.
formylglycine-generating enzyme - fluorescens pf-5 - burkholderia-glumae - pyoluteorin - cocovenenans - expression - oxidation - system - rice - gaca
Pseudomonas spp. are prolific producers of natural products from many structural classes. Here we show that the soil bacterium Pseudomonas protegens Pf-5 is capable of producing trace levels of the triazine natural product toxoflavin (1) under microaerobic conditions. We evaluated toxoflavin production by derivatives of Pf-5 with deletions in specific biosynthesis genes, which led us to propose a revised biosynthetic pathway for toxoflavin that shares the first two steps with riboflavin biosynthesis. We also report that toxM, which is not present in the well-characterized cluster of Burkholderia glumae, encodes a monooxygenase that degrades toxoflavin. The toxoflavin degradation product of ToxM is identical to that of TflA, the toxoflavin lyase from Paenibacillus polymyxa. Toxoflavin production by P. protegens causes inhibition of several plant-pathogenic bacteria, and introduction of toxM into the toxoflavin-sensitive strain Pseudomonas syringae DC3000 results in resistance to toxoflavin.
Mating type and sexual fruiting body of Botrytis elliptica, the causal agent of fire blight in lily
Terhem, R.B. ; Staats, M. ; Kan, J.A.L. van - \ 2015
European Journal of Plant Pathology 142 (2015)3. - ISSN 0929-1873 - p. 615 - 624.
cinerea - leaves - resistance - infection - behavior - system
Botrytis elliptica is a necrotrophic pathogen that specifically infects Lilium species. Previous records show that B. elliptica collected in the field can successfully develop apothecia in vitro, however, there are no formal descriptions of apothecia of B. elliptica. The aim of this study was to analyse the sequence of the mating type loci of B. elliptica and produce apothecia in the laboratory in order to describe their morphology. The sequences of both MAT alleles (MAT1-1 or MAT1-2) of B. elliptica were determined and compared to the sister taxa, Botrytis cinerea and Sclerotinia sclerotiorum. Two strains of each mating type were used in crosses under controlled conditions to produce apothecia. Primordium rupture from sclerotial tissue occurred 74 days after fertilization and a mature apothecium formed within 1 month after rupture. The apothecia are 7 to 12 mm in height with a disk of 3 to 4 mm in diameter and 0.5 to 1 mm in thickness. The apothecial disk is usually umbilicate, depressed to funnel and rounded in shape. The number of apothecia growing on a sclerotium was one to nine. Asci are long, cylindrical with a size of 208¿×¿14 µm, thin walled and bearing eight ascospores. Ascospores are hyaline in colour, ellipsoidal with rounded ends, usually 18 to 24 µm in length and 6 to 10 µm in width (mean 19.5¿×¿8 µm). Ascospores were infectious on lily leaves.
Sectorial Water Use Trends in the Urbanizing Pearl River Delta, China
Yao, M. ; Werners, S.E. ; Hutjes, R.W.A. ; Kabat, P. ; Huang, H.Q. - \ 2015
PLoS One 10 (2015)2. - ISSN 1932-6203 - 20 p.
south china - climate-change - demand model - availability - drainage - impacts - streams - system - growth
Assessing and managing water use is crucial for supporting sustainable river basin management and regional development. The first consistent and comprehensive assessment of sectorial water use in the Pearl River Delta (PRD) is presented by analysing homogenized annual water use data from 2000 to 2010 in relation to socio economic statistics for the same period. An abstraction of water use, using the concept of water use intensity, and based on equations inspired by those used in global water resource models, is developed to explore the driving forces underlying water use changes in domestic, industrial and agricultural sectors. We do this at both the level of the region as a whole, as well as for the nine cities that constitute the PRD separately. We find that, despite strong population and economic growth, the PRD managed to stabilize its absolute water use by significant improvements in industrial water use intensities, and early stabilisation of domestic water use intensities. Results reveal large internal differentiation of sectorial water use among the cities in this region, with industrial water use intensity varying from -80 to +95% and domestic water use intensity by +/- 30% compared to the PRD average. In general, per capita water use is highest in the cities that industrialised first. Yet, all cities except Guangzhou are expected to approach a saturation value of per capita water use much below what is suggested in recent global studies. Therefore, existing global assessments probably have overestimated future domestic water use in developing countries. Although scarce and uncertain input data and model limitations lead to a high level of uncertainty, the presented conceptualization of water use is useful in exploring the underlying driving forces of water use trends.
Early feeding and early life housing conditions influence the response towards a noninfectious lung challenge in broilers
Simon, K. ; Vries Reilingh, G. de; Bolhuis, J.E. ; Kemp, B. ; Lammers, A. - \ 2015
Poultry Science 94 (2015)9. - ISSN 0032-5791 - p. 2041 - 2048.
intestinal immune-responses - symbiotic bacteria - delayed access - laying hens - germ-free - system - colonization - performance - maturation - microbiota
Early life conditions such as feed and water availability immediately post hatch (p.h.) and housing conditions may influence immune development and therefore immune reactivity later in life. The current study addressed the consequences of a combination of these 2 early life conditions for immune reactivity, i.e., the specific antibody response towards a non-infectious lung challenge. Broiler chicks received feed and water either immediately p.h. or with a 72 h delay and were either reared in a floor or a cage system. At 4 weeks of age, chicks received either an intra-tracheally administered Escherichia coli lipopolysaccharide (LPS)/Human Serum Albumin (HuSA) challenge or a placebo, and antibody titers were measured up to day 14 after administration of the challenge. Chicks housed on the floor and which had a delayed access to feed p.h. showed the highest antibody titers against HuSA. These chicks also showed the strongest sickness response and poorest performance in response to the challenge, indicating that chicks with delayed access to feed might be more sensitive to an environment with higher antigenic pressure. In conclusion, results from the present study show that early life feeding strategy and housing conditions influence a chick's response to an immune challenge later in life. These 2 early life factors should therefore be taken into account when striving for a balance between disease resistance and performance in poultry.
Electrophysiological and behavioural responses of turbot (Scophthalmus maximus) cooled in ices water
Lambooij, E. ; Bracke, M.B.M. ; Reimert, H.G.M. ; Foss, A. ; Imsland, A. ; Vis, J.W. van de - \ 2015
Physiology and Behavior 149 (2015). - ISSN 0031-9384 - p. 23 - 28.
fish - welfare - pain - stress - system - l.
Behavioural, neural and physiological aspects related to pre-slaughter cooling of turbot habituated to two environmental temperatures (18.7 and 12.0 °C) were investigated. Six fish in both treatments were immersed in ice water for 75 min. For control, four fish were immersed in water under their habituated environmental temperature. Turbot did not show a quick reduction of overall power in the EEG (electroencephalogram) to less than 10%, nor did the turbot show a shift in brain wave predominance from high to low frequency waves. At 15 min after immersion in ice water at least 7 out of 12 fish still showed total power values over 10% of pre-immersion values. Significant reductions in responsiveness to needle scratches and reduced breathing after immersion in ice waterwere observed, but none of these parameters had dropped to 0 even after 75 min in icewater. A significant reduction in gill score was found at 2 and 5 min after immersion in ice water compared to the control fish (p
Spatial and seasonal diversity of wild food plants in home gardens of Northeast Thailand
Cruz Garcia, G.S. ; Struik, P.C. - \ 2015
Economic Botany 69 (2015)2. - ISSN 0013-0001 - p. 99 - 113.
tropical homegardens - west-bengal - system - weeds - biodiversity - management - resources - medicine - vietnam - mexico
Wild food plants (WFPs) are major components of tropical home gardens, constituting an important resource for poor farmers. The spatial and seasonal diversity of WFPs was analyzed across multi-species spatial configurations occurring within home gardens in a rice farming village in northeast Thailand. Data were collected in 77 sampling sites corresponding to five different home garden spatial configurations, namely fenced plot, fenced plot margin, yard, home garden boundary, and pot. Absolute abundance and frequency of occurrence were quantified per individual WFP species in both dry and rainy seasons, and data on additional uses (besides food) were collected through focus group discussions for each WFP species. A total of 20 species corresponding to 13 botanical families were reported. Results show that species abundance and frequency of occurrence varied seasonally and spatially within home gardens. Diversity, as observed in the analysis of Shannon and Simpson diversity indexes, also differed seasonally and across different spatial configurations. Home gardens showed higher diversity in the dry season because of the presence of human management. Ninety-five percent of the WFP species presented additional uses, with nine different types of uses in total. Finally, as this study demonstrates, the results on both the spatial and seasonal diversity of WFPs over different spatial configurations comprise a new perspective in home garden research by providing new understandings about their composition and management.
Simulating the reactions of CO2 in aqueous monoethanolamine solution by Reaction Ensemble Monte Carlo using the Continuous Fractional Component method
Balaji, S.P. ; Gangarapu, S. ; Ramdin, M. ; Torres-Knoop, A. ; Zuilhof, H. ; Goetheer, E. ; Dubbeldam, D. ; Vlugt, T. - \ 2015
Journal of Chemical Theory and Computation 11 (2015)6. - ISSN 1549-9618 - p. 2661 - 2669.
chemical-reaction equilibria - sterically hindered amines - aerosol based emission - carbon-dioxide - molecular simulation - computer-simulation - phase-equilibria - capture - system - performance
Molecular simulations were used to compute the equilibrium concentrations of the different species in CO2/monoethanolamine solutions for different CO2 loadings. Simulations were performed in the Reaction Ensemble using the continuous fractional component Monte Carlo method at temperatures of 293, 333, and 353 K. The resulting computed equilibrium concentrations are in excellent agreement with experimental data. The effect of different reaction pathways was investigated. For a complete understanding of the equilibrium speciation, it is essential to take all elementary reactions into account because considering only the overall reaction of CO2 with MEA is insufficient. The effects of electrostatics and intermolecular van der Waals interactions were also studied, clearly showing that solvation of reactants and products is essential for the reaction. The Reaction Ensemble Monte Carlo using the continuous fractional component method opens the possibility of investigating the effects of the solvent on CO2 chemisorption by eliminating the need to study different reaction pathways and concentrate only on the thermodynamics of the system.
Low-resolution modeling of dense drainage networks in confining layers
Pauw, P.S. ; Zee, S.E.A.T.M. van der; Leijnse, A. ; Delsman, J.R. ; Louw, P.G.B. de; Lange, W.J. de; Oude Essink, G.H.P. - \ 2015
Groundwater 53 (2015)5. - ISSN 0017-467X - p. 771 - 781.
grondwaterstroming - watervoerende lagen - modellen - klimaatverandering - groundwater flow - aquifers - models - climatic change - aquifer - simulation - intrusion - seepage - florida - system - field - flow
Groundwater-surface water (GW-SW) interaction in numerical groundwater flow models is generally simulated using a Cauchy boundary condition, which relates the flow between the surface water and the groundwater to the product of the head difference between the node and the surface water level, and a coefficient, often referred to as the “conductance.” Previous studies have shown that in models with a low grid resolution, the resistance to GW-SW interaction below the surface water bed should often be accounted for in the parameterization of the conductance, in addition to the resistance across the surface water bed. Three conductance expressions that take this resistance into account were investigated: two that were presented by Mehl and Hill (2010) and the one that was presented by De Lange (1999). Their accuracy in low-resolution models regarding salt and water fluxes to a dense drainage network in a confined aquifer system was determined. For a wide range of hydrogeological conditions, the influence of (1) variable groundwater density; (2) vertical grid discretization; and (3) simulation of both ditches and tile drains in a single model cell was investigated. The results indicate that the conductance expression of De Lange (1999) should be used in similar hydrogeological conditions as considered in this paper, as it is better taking into account the resistance to flow below the surface water bed. For the cases that were considered, the influence of variable groundwater density and vertical grid discretization on the accuracy of the conductance expression of De Lange (1999) is small.
Production of structured soy-based meat analogues using simple shear and heat in a Couette Cell
Krintiras, G.A. ; Gobel, T.W. ; Goot, A.J. van der; Stefanidis, G.D. - \ 2015
Journal of Food Engineering 160 (2015). - ISSN 0260-8774 - p. 34 - 41.
calcium caseinate dispersions - functional-properties - process parameters - extrusion-cooking - fibrous materials - protein isolate - wheat gluten - microstructure - mixtures - system
A Couette Cell device was employed to provide proof of concept for the production of structured meat analogues by application of simple shear flow and heat to a 31 wt% Soy Protein Isolate (SPI)–Wheat Gluten (WG) dispersion. Three relevant process parameters (temperature, time and rotation rate) were varied over a range of realistic values (90–110 °C, 5–25 min and 5–50 RPM, respectively). Layer- or fibre-structured products with high stress and strain anisotropy indices have been demonstrated. Fibrousness is favoured at temperatures over 90 °C and under 100 °C, whereas the role of process time and rotation rate is not critical. Simultaneous application of simple shear and heat is the key to obtaining structured plant protein-based products. The Couette Cell concept is scalable and can enable continuous operation. On this ground, it appears as a realistic option for production of meat analogues at commercial scale.
Organogel formation via supramolecular assembly of oleic acid and sodium oleate
Nikiforidis, C.V. ; Gilbert, E.P. ; Scholten, E. - \ 2015
RSC Advances : An international journal to further the chemical sciences 5 (2015)59. - ISSN 2046-2069 - p. 47466 - 47475.
system - solvent - liquid - amphiphiles - particles - micelles - lecithin - bilayers - laurate - water
To create materials with novel functionalities, the formation of gels within hydrophobic media has become popular. This is often accomplished through the assembly of low molecular weight organogelators into a variety of complex phases through intermolecular interactions. In the case of edible materials, the assembly of saturated fatty acids to form fat crystal networks is often used for structuring. Here, the first example of structuring with unsaturated fatty acids is reported, namely mixtures of oleic acid and sodium oleate, to structure edible lipid phases. Small-angle scattering demonstrates that the resultant structures, which vary with oleic acid and sodium oleate molar ratio, comprise either inverse micellar or lamellar phases, combined with the formation of crystalline space-filling networks. Network formation was found for filler concentrations above 10 wt%. Rheological measurements show that gel strength depends on the ratio of oleic acid to sodium oleate, and is greater when only oleic acid is used. The addition of up to 1.5 wt% of water enhanced the strength of the organogels, probably through supplementary hydrogen bonding but, for concentrations greater than 2.0 wt%, the assembly was inhibited leading to collapse of the gel.
Consumer-Related Food Waste: Causes and Potential for Action
Aschemann-Witzel, J. ; Hooge, I.E. de; Amani, P. ; Bech-Larsen, T. ; Oostindjer, M. - \ 2015
Sustainability 7 (2015). - ISSN 2071-1050 - p. 6457 - 6477.
climate-change - behavior - consumption - households - separation - emissions - knowledge - attitude - impacts - system
In the past decade, food waste has received increased attention on both academic and societal levels. As a cause of negative economic, environmental and social effects, food waste is considered to be one of the sustainability issues that needs to be addressed. In developed countries, consumers are one of the biggest sources of food waste. To successfully reduce consumer-related food waste, it is necessary to have a clear understanding of the factors influencing food waste-related consumer perceptions and behaviors. The present paper presents the results of a literature review and expert interviews on factors causing consumer-related food waste in households and supply chains. Results show that consumers’ motivation to avoid food waste, their management skills of food provisioning and food handling and their trade-offs between priorities have an extensive influence on their food waste behaviors. We identify actions that governments, societal stakeholders and retailers can undertake to reduce consumer-related food waste, highlighting that synergistic actions between all parties are most promising. Further research should focus on exploring specific food waste contexts and interactions more in-depth. Experiments and interventions in particular can contribute to a shift from analysis to solutions.
Effects of dry period length and dietary energy source on metabolic status and hepatic gene expression of dairy cows in early lactation
Chen, J.C. ; Gross, J.J. ; Dorland, H.A. van; Remmelink, G.J. ; Bruckmaier, R.M. ; Kemp, B. ; Knegsel, A.T.M. van - \ 2015
Journal of Dairy Science 98 (2015)2. - ISSN 0022-0302 - p. 1033 - 1045.
organic nutrient metabolism - messenger-rna - transition period - somatotropic axis - milk-production - fatty-acids - liver - balance - system - performance
In a prior study, we observed that cows with a 0-d dry period had greater energy balance and lower milk production compared with cows with a 30- or 60-d dry period in early lactation. The objective of the current study was to evaluate the influence of dry period length on metabolic status and hepatic gene expression in cows fed a lipogenic or glucogenic diet in early lactation. Holstein-Friesian dairy cows (n = 167) were assigned randomly to 3 × 2 factorial design with 3 dry period lengths (n = 56, 55, and 56 for 0-, 30-, and 60-d dry, respectively) and 2 early lactation diets (n = 84 and 83 for glucogenic and lipogenic diet, respectively). Cows were fed a glucogenic or lipogenic diet from 10 d before the expected calving date and onward. The main ingredient for a glucogenic concentrate was corn, and the main ingredients for a lipogenic concentrate were sugar beet pulp, palm kernel, and rumen-protected palm oil. Blood was sampled weekly from 95 cows from wk 3 precalving to wk 8 postcalving. Liver samples were collected from 76 cows in wk -2, 2, and 4 relative to calving. Liver samples were analyzed for triacylglycerol concentrations and mRNA expression of 12 candidate genes. Precalving, cows with a 0-d dry period had greater plasma ß-hydroxybutyrate, urea, and insulin concentrations compared with cows with a 30- or 60-d dry period. Postcalving, cows with a 0-d dry period had lower liver triacylglycerol and plasma nonesterified fatty acids concentrations (0.20, 0.32, and 0.36 mmol/L for 0-, 30-, and 60-d dry period, respectively), greater plasma glucose, insulin-like growth factor-I, and insulin (24.38, 14.02, and 11.08 µIU/mL for 0-, 30-, and 60-d dry period, respectively) concentrations, and lower hepatic mRNA expression of pyruvate carboxylase, compared with cows with a 30- or 60-d dry period. Plasma urea and ß-hydroxybutyrate concentrations were greater in cows fed a lipogenic diet compared with cows fed a glucogenic diet. In conclusion, cows with a 0-d dry period had an improved metabolic status in early lactation, indicated by lower plasma concentrations of nonesterified fatty acids, greater plasma concentrations of glucose, insulin-like growth factor-I, and insulin, and lower mRNA expression of pyruvate carboxylase in the liver, compared with cows with a 30- or 60-d dry period. Independent of dry period length, the glucogenic diet also improved the metabolic status compared with the lipogenic diet.
Limited evidence for trans-generational effects of maternal dietary supplementation with ¿-3 fatty acids on immunity in broiler chickens
Koppenol, A. ; Delezie, E. ; Parmentier, H.K. ; Buyse, J. ; Everaert, N. - \ 2015
The Veterinary Journal 203 (2015)2. - ISSN 1090-0233 - p. 244 - 249.
n-3 fatty-acids - red-blood-cells - antibody-responses - escherichia-coli - serum - system - immunoglobulin - proliferation - inflammation - performance
The aim of the present study was to investigate whether the immune response of broiler chickens is modulated by including different omega-3 (¿-3) polyunsaturated fatty acids (PUFAs) in the maternal diet. Broiler breeder hens (n¿=¿120 birds per group) were fed one of four diets, differing in the ratios of n-6:n-3 PUFAs and eicosapentaenoic acid (EPA):docosahexaenoic acid (DHA). At 28 weeks of age, the eggs produced were incubated to obtain 720 chicks (n¿=¿180 per group). All broiler chicks were fed a control diet and were vaccinated against Newcastle disease virus (NDV). Blood samples were taken at different time points after immunisation with human serum albumin (HuSA) in Freund's adjuvant to determine the acute phase response, antibody response and cytokine production. Addition of EPA to the maternal diet was associated with greater ovotransferrin concentrations post-immunisation, compared to other groups. Altering the ratios of n-6:n-3 PUFA or EPA:DHA in the maternal diet did not affect the offspring in terms of production of caeruloplasmin, a1-acid glycoprotein, interleukin (IL)-1ß, IL-6, IL-12 or tumour necrosis factor (TNF)-a. Dietary manipulation of the maternal diet did not influence the specific antibody response to HuSA or NDV, nor did it alter the levels of natural antibody binding to keyhole limpet haemocyanin in the offspring. Thus, maternal supplementation with n-3 PUFAs played a minor role in perinatal programming of the immune response of broiler chickens.
The need for reflexive evaluation approaches in development cooperation
Arkesteijn, M.C.M. ; Mierlo, B. van; Leeuwis, C. - \ 2015
Evaluation : The International Journal of Theory, Research and Practice 21 (2015)1. - ISSN 1356-3890 - p. 99 - 115.
innovation - system - complexity - framework - poverty - design - benin - story
Within development cooperation, development issues are increasingly recognized as complex problems requiring new paths towards solving them. In addition to the commonly used two dimensions of complex problems (uncertainty and disagreement), we introduce a third dimension: systemic stability; that is, stability provided by rules, relations and complementary technology. This article reflects on how development evaluation methodologies and especially those introducing a complexity perspective address these three dimensions. Inferring that this third dimension deserves more attention, we explore the characteristics of reflexive evaluation approaches that challenge systemic stability and support processes of learning and institutional change. We conclude that reflexive evaluation approaches may well complement current system approaches in development evaluation practice.
Unveiling soil degradation and desertification risk in the Mediterranean basin: a data mining analysis of the relationships between biophysical and socioeconomic factors in agro-forest landscapes
Salvati, L. ; Kosmas, C. ; Kairis, O. ; Karavitis, C. ; Hessel, R. ; Ritsema, C.J. - \ 2015
Journal of Environmental Planning and Management 58 (2015)10. - ISSN 0964-0568 - p. 1789 - 1803.
land-use change - abandonment - erosion - vulnerability - performance - indicators - region - europe - system - spain
Soil degradation and desertification processes in the Mediterranean basin reflect the interplay between environmental and socioeconomic drivers. An approach to evaluate comparatively the multiple relationships between biophysical variables and socioeconomic factors is illustrated in the present study using the data collected from 586 field sites located in five Mediterranean areas (Spain, Greece, Turkey, Tunisia and Morocco). A total of 47 variables were chosen to illustrate land-use, farm characteristics, population pressure, tourism development, rainfall regime, water availability, soil properties and vegetation cover, among others. A data mining approach incorporating non-parametric inference, principal component analysis and hierarchical clustering was developed to identify candidate syndromes of soil degradation and desertification risk. While field sites in the same study area showed a substantial similarity, the multivariate relationship among variables diverged among study areas. Data mining techniques proved to be a practical tool to identify spatial determinants of soil degradation and desertification risk. Our findings identify the contrasting spatial patterns for biophysical and socioeconomic variables, in turn associated with different responses to land degradation.
Electricity generation by a plant microbial fuel cell with an integrated oxygen reducing biocathode
Wetser, K. ; Sudirjo, E. ; Buisman, C.J.N. ; Strik, D.P.B.T.B. - \ 2015
Applied energy 137 (2015). - ISSN 0306-2619 - p. 151 - 157.
determine performance - living plants - reduction - oxidation - biofilms - system
In this study we show that a chemical ferricyanide cathode can be replaced by a biological oxygen reducing cathode in a plant microbial fuel cell (PMFC) with a new record power output. A biocathode was successfully integrated in a PMFC and operated for 151 days. Plants growth continued and the power density increased reaching a maximum power output of 679 mW/m2 plant growth area (PGA) in a 10 min polarization. The two week record average power densities was 240 mW/m2 PGA. The new records were reached due to the high redox potential of oxygen reduction which was effectively catalyzed by microorganisms in the cathode. This resulted in a 127 mV higher cathode potential of the PMFC with a biocathode than a PMFC with a ferricyanide cathode. We also found that substrate availability in the anode likely limits the current generation. This work is crucial for PMFC application as it shows that PMFC can be a completely sustainable biotechnology with an improved power output.
Quantitative economic impact assessment of invasive plant pests: What does it require and when is it worth the effort?
Soliman, T.A.A. ; Mourits, M.C.M. ; Oude Lansink, A.G.J.M. ; Werf, W. van der - \ 2015
Crop Protection 69 (2015). - ISSN 0261-2194 - p. 9 - 17.
maps - ecology - disease - system - growth
According to the International Plant Protection Convention and theWorld Trade Organization Agreement on the Application of Sanitary and Phytosanitary measures, any measure against the introduction and spread of new pests must be justified by a science-based pest risk analysis. Economic impact assessments are usually carried out using a qualitative approach, based on classifying the size of impact into five categories, from “minimal” to “massive”. Whilst the qualitative approach may be adequate in many instances, it lacks transparency and demonstrable objectivity. A quantitative approach for economic impact assessment may improve transparency and strengthen the justification for measures, if taken, but requires additional work, and it requires specific data and models. This paper, first, compares the strengths and weaknesses of qualitative and quantitative approaches. Second, it clarifies the data and models needed to conduct a quantitative economic impact assessment to support a decision on the pest quarantine status or justify management measures. Third, it identifies the criteria for choosing the appropriate level of complexity, regarding the resolution, economic technique and time frame of the quantitative approach. The greater transparency and objectivity of the quantitative vis-a-vis qualitative economic impact assessment may enhance plant health policy and decision making at national and international regulatory bodies. However, uncertainties that are inherent to this approach may weaken this position. Hence, PRAs require a mixture of quantitative and qualitative approaches for assessing impacts and the exact balance of the two has to be case-specific.
Free and open-access satellite data are key to biodiversity conservation
Turner, W. ; Rondinini, C. ; Pettorelli, N. ; Mora, B. ; Leidner, A.K. ; Szantoi, Z. ; Buchanan, G. ; Dech, S. ; Dwyer, J. ; Herold, M. ; Koh, L.P. ; Leimgruber, P. ; Taubenboeck, H. ; Wegmann, M. ; Wikelski, M. ; Woodcock, C. - \ 2015
Biological Conservation 182 (2015). - ISSN 0006-3207 - p. 173 - 176.
landsat imagery - cover change - science - opportunities - challenges - support - system
Satellite remote sensing is an important tool for monitoring the status of biodiversity and associated environmental parameters, including certain elements of habitats. However, satellite data are currently underused within the biodiversity research and conservation communities. Three factors have significant impact on the utility of remote sensing data for tracking and understanding biodiversity change. They are its continuity, affordability, and access. Data continuity relates to the maintenance of long-term satellite data products. Such products promote knowledge of how biodiversity has changed over time and why. Data affordability arises from the cost of the imagery. New data policies promoting free and open access to government satellite imagery are expanding the use of certain imagery but the number of free and open data sets remains too limited. Data access addresses the ability of conservation biologists and biodiversity researchers to discover, retrieve, manipulate, and extract value from satellite imagery as well as link it with other types of information. Tools are rapidly improving access. Still, more cross-community interactions are necessary to strengthen ties between the biodiversity and remote sensing communities.
Check title to add to marked list
<< previous | next >>

Show 20 50 100 records per page

 
Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.