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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An analysis of characterized plant sesquiterpene synthases
Durairaj, Janani ; Girolamo, Alice Di; Bouwmeester, Harro J. ; Ridder, Dick de; Beekwilder, Jules ; Dijk, Aalt D.J. van - \ 2018
Phytochemistry (2018). - ISSN 0031-9422 - 9 p.
Database - Enzyme - Product specificity - Sesquiterpene - Sesquiterpene synthase - Terpene synthase

Plants exhibit a vast array of sesquiterpenes, C15 hydrocarbons which often function as herbivore-repellents or pollinator-attractants. These in turn are produced by a diverse range of sesquiterpene synthases. A comprehensive analysis of these enzymes in terms of product specificity has been hampered by the lack of a centralized resource of sufficient functionally annotated sequence data. To address this, we have gathered 262 plant sesquiterpene synthase sequences with experimentally characterized products. The annotated enzyme sequences allowed for an analysis of terpene synthase motifs, leading to the extension of one motif and recognition of a variant of another. In addition, putative terpene synthase sequences were obtained from various resources and compared with the annotated sesquiterpene synthases. This analysis indicated regions of terpene synthase sequence space which so far are unexplored experimentally. Finally, we present a case describing mutational studies on residues altering product specificity, for which we analyzed conservation in our database. This demonstrates an application of our database in choosing likely-functional residues for mutagenesis studies aimed at understanding or changing sesquiterpene synthase product specificity.

Multiscale socio-ecological networks in the age of information
Lenormand, Maxime ; Luque, Sandra ; Langemeyer, Johannes ; Tenerelli, Patrizia ; Zulian, Grazia ; Aalders, Inge ; Chivulescu, Serban ; Clemente, Pedro ; Dick, Jan ; Dijk, Jiska van; Eupen, Michiel van; Giuca, Relu C. ; Kopperoinen, Leena ; Lellei-Kovács, Eszter ; Leone, Michael ; Lieskovský, Juraj ; Schirpke, Uta ; Smith, Alison C. ; Tappeiner, Ulrike ; Woods, Helen - \ 2018
PLoS One 13 (2018)11. - ISSN 1932-6203

Interactions between people and ecological systems, through leisure or tourism activities, form a complex socio-ecological spatial network. The analysis of the benefits people derive from their interactions with nature-also referred to as cultural ecosystem services (CES)-enables a better understanding of these socio-ecological systems. In the age of information, the increasing availability of large social media databases enables a better understanding of complex socio-ecological interactions at an unprecedented spatio-temporal resolution. Within this context, we model and analyze these interactions based on information extracted from geotagged photographs embedded into a multiscale socio-ecological network. We apply this approach to 16 case study sites in Europe using a social media database (Flickr) containing more than 150,000 validated and classified photographs. After evaluating the representativeness of the network, we investigate the impact of visitors' origin on the distribution of socio-ecological interactions at different scales. First at a global scale, we develop a spatial measure of attractiveness and use this to identify four groups of sites. Then, at a local scale, we explore how the distance traveled by the users to reach a site affects the way they interact with this site in space and time. The approach developed here, integrating social media data into a network-based framework, offers a new way of visualizing and modeling interactions between humans and landscapes. Results provide valuable insights for understanding relationships between social demands for CES and the places of their realization, thus allowing for the development of more efficient conservation and planning strategies.

The Ostrich Politics of Groundwater Development and Neoliberal Regulation in Mexico
Hoogesteger van Dijk, J.D. - \ 2018
Water Alternatives 11 (2018)3. - ISSN 1965-0175 - p. 552 - 571.
In this article I present the politics that spurred groundwater development in Central and Northern Mexico between 1930 and 1990, and analyse the working/effects of the neoliberal groundwater policies that were implemented in the country since the 1990s. I first present, based on an analysis of the Comarca Lagunera and the state of Guanajuato, the socio-economic, political and institutional dynamics that shaped groundwater development between 1930 and 1990, with a special focus on how with state support large commercial farmers and small ejidatarios developed groundwater irrigation. My analysis shows how the actors involved in groundwater development, just like ostriches, stuck their head in the sand, oblivious to aquifer overdraft and its environmental consequences. Then I present how – since the 1990s – neoliberal groundwater regulation policies have worked out on the ground opening the doors to regulatory capture and groundwater accumulation through capital, oblivious to sustained aquifer overdraft, a shrinking peasant ejido sector, increased rural outmigration and the health threat of toxic concentration of Fluoride and Arsenic in many groundwater dependent areas. This analysis raises serious doubts about the capacity of – often (inter)nationally lauded – neoliberally inspired groundwater policies to contribute to socio-environmental sustainability and equity.
Arsenite removal in groundwater treatment plants by sequential Permanganate―Ferric treatment
Ahmad, Arslan ; Cornelissen, Emile ; Wetering, Stephan van de; Dijk, Tim van; Genuchten, Case van; Bundschuh, Jochen ; Wal, Albert van der; Bhattacharya, Prosun - \ 2018
Journal of Water Process Engineering 26 (2018). - ISSN 2214-7144 - p. 221 - 229.
Arsenic removal - Arsenite oxidation - Drinking water - Groundwater treatment - Permanganate - Rapid sand filtration

The Dutch drinking water sector is actively investigating methods to reduce arsenic (As) to <1 μg/L in drinking water supply. We investigated (1) the effectiveness of sequential permanganate (MnO4¯ )–ferric (Fe(III)) dosing during aeration–rapid sand filtration to achieve <1 μg/L As (2) the influence of MnO4¯ –Fe(III) dosing on pre-established removal patterns of As(III), Fe(II), Mn(II) and NH4 + in rapid sand filters and (3) the influence of MnO4¯ –Fe(III) dosing on the settling and molecular-scale structural properties of the filter backwash solids. We report that MnO4¯ –Fe(III) dosing is an effective technique to improve arsenite [As(III)] removal at groundwater treatment plants. At a typical aeration—rapid sand filtration facility in the Netherlands effluent As concentrations of <1 μg/L were achieved with 1.2 mg/L MnO4 ¯–and 1.8 mg/L Fe(III). The optimized combination of MnO4¯ –and Fe(III) doses did not affect the removal efficiency of Fe(II), Mn(II) and NH4 + in rapid sand filters, however, the removal patterns of Fe(II) and Mn(II) in rapid sand filter were altered, as well as the settling behaviour of backwash solids. The characterization of backwash solids by Fe K-edge X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) showed that the changed settling velocity of backwash solids with MnO4¯ –Fe(III) in place was not due to changes in the molecular-scale structure of Fe-precipitates that constitute the major portion of the backwash solids.

A new model to Calibrate a Reference Standard for bovine tuberculin purified protein derivative in the target species
Frankena, Klaas ; Jacobs, Liesbeth ; Dijk, Tonny van; Good, Margaret ; Duignan, Anthony ; Jong, Mart C.M. de - \ 2018
Frontiers in Veterinary Science 5 (2018)OCT. - ISSN 2297-1769
Bovine international standard - Cattle - Guinea pigs - Mycobacterium bovis - New reference standard - Potency estimation - Tuberculin

Since 1986, use of a Bovine International Standard (BIS) for bovine tuberculin has been required to ensure national and international uniformity regarding the potency designation of bovine tuberculin Purified Protein Derivative (PPDb) preparations produced by multiple manufacturers. The BIS is the unique golden standard in the guinea pig potency assay, representing 100% potency, where potencies of production batches are calculated as relative potencies in comparison with the potency of the BIS which was set at 32,500 international Unit (IU) per mg. The stock supply and lifetime of the BIS is limited.The aim of this study was to develop a model to determine the potency of a newly produced in-house Reference Standard (RS) for PPDb with great accuracy in the target species (cattle) and to prove its precision and accuracy in the guinea pig potency test. First simulations were done to estimate the required number of cattle needed. Then, 30 naturally bTB infected cattle were subjected to a tuberculin skin test using multiple injections of both the RS and the BIS. Both were applied randomly in the same volume and concentration (1 dose). The potency of the RS against the BIS was directly derived from the least square means (LSMEANS) and was estimated as 1.067 (95% CI: 1.025-1.109), equal to a potency of 34,700 ± 1,400 IU/mg. In six guinea pig potency assays the RS was used to assign potencies to production batches of PPDb. Here, precision and accuracy of the RS was determined according to the parallel-line assay. Relative potencies were estimated by exponentiation of the common slope. The corresponding 95% confidence intervals were obtained according to Fieller's theorem. In sensitized guinea pigs, the relative potency of the RS against the BIS was 1.115 (95% CI: 0.871-1.432), corresponding to an absolute potency of 36,238 IU/mg (95% CI: 28,308-46,540).In conclusion: the method used to determine the potency of the RS against the BIS in naturally bTB infected cattle, resulted in a highly accurate potency estimate of the RS. The RS can be used in the guinea pig test to assign potencies to PPDb production batches with high precision and accuracy.

Global 5 km resolution estimates of secondary evaporation including irrigation through satellite data assimilation
Dijk, Albert I.J.M. Van; Schellekens, Jaap ; Yebra, Marta ; Beck, Hylke E. ; Renzullo, Luigi J. ; Weerts, Albrecht ; Donchyts, Gennadii - \ 2018
Hydrology and Earth System Sciences 22 (2018)9. - ISSN 1027-5606 - p. 4959 - 4980.

A portion of globally generated surface and groundwater resources evaporates from wetlands, waterbodies and irrigated areas. This secondary evaporation of blue water directly affects the remaining water resources available for ecosystems and human use. At the global scale, a lack of detailed water balance studies and direct observations limits our understanding of the magnitude and spatial and temporal distribution of secondary evaporation. Here, we propose a methodology to assimilate satellite-derived information into the landscape hydrological model W3 at an unprecedented 0.05°, or ca. 5 km resolution globally. The assimilated data are all derived from MODIS observations, including surface water extent, surface albedo, vegetation cover, leaf area index, canopy conductance and land surface temperature (LST). The information from these products is imparted on the model in a simple but efficient manner, through a combination of direct insertion of the surface water extent, an evaporation flux adjustment based on LST and parameter nudging for the other observations. The resulting water balance estimates were evaluated against river basin discharge records and the water balance of closed basins and demonstrably improved water balance estimates compared to ignoring secondary evaporation (e.g., bias improved from +38 to +2 mm yr-1). The evaporation estimates derived from assimilation were combined with global mapping of irrigation crops to derive a minimum estimate of irrigation water requirements (I0), representative of optimal irrigation efficiency. Our I0 estimates were lower than published country-level estimates of irrigation water use produced by alternative estimation methods, for reasons that are discussed. We estimate that 16 % of globally generated water resources evaporate before reaching the oceans, enhancing total terrestrial evaporation by 6.1×1012 m3 yr-1 or 8.8 %. Of this volume, 5 % is evaporated from irrigation areas, 58 % from terrestrial waterbodies and 37 % from other surfaces. Model-data assimilation at even higher spatial resolutions can achieve a further reduction in uncertainty but will require more accurate and detailed mapping of surface water dynamics and areas equipped for irrigation.

Angiopoietin-like 4 promotes the intracellular cleavage of lipoprotein lipase by PCSK3/furin in adipocytes
Dijk, Wieneke ; Ruppert, Philip M.M. ; Oost, Lynette J. ; Kersten, Sander - \ 2018
Journal of Biological Chemistry 293 (2018)36. - ISSN 0021-9258 - p. 14134 - 14145.

Lipoprotein lipase (LPL) catalyzes the breakdown of circulating triglycerides in muscle and fat. LPL is inhibited by several proteins, including angiopoietin-like 4 (ANGPTL4), and may be cleaved by members of the proprotein convertase subtilisin/ kexin (PCSK) family. Here, we aimed to investigate the cleavage of LPL in adipocytes by PCSKs and study the potential involvement of ANGPTL4. A substantial portion of LPL in mouse and human adipose tissue was cleaved into N- and C-terminal fragments. Treatment of different adipocytes with the PCSK inhibitor decanoyl-RVKR-chloromethyl ketone markedly decreased LPL cleavage, indicating that LPL is cleaved by PCSKs. Silencing of Pcsk3/furin significantly decreased LPL cleavage in cell culture medium and lysates of 3T3-L1 adipocytes. Remarkably, PCSK-mediated cleavage of LPL in adipocytes was diminished by Angptl4 silencing and was decreased in adipocytes and adipose tissue of Angptl4/ mice. Differences in LPL cleavage between Angptl4/ and WT mice were abrogated by treatment with decanoyl-RVKR-chloromethyl ketone. Induction of ANGPTL4 in adipose tissue during fasting enhanced PCSK-mediated LPL cleavage, concurrent with decreased LPL activity, in WT but not Angptl4/ mice. In adipocytes, after removal of cell surface LPL by heparin, levels of N-terminal LPL were still markedly higher in WT compared with Angptl4/ adipocytes, suggesting that stimulation of PCSK-mediated LPL cleavage by ANGPTL4 occurs intracellularly. Finally, treating adipocytes with insulin increased full-length LPL and decreased N-terminal LPL in an ANGPTL4-dependent manner. In conclusion, ANGPTL4 promotes PCSK-mediated intracellular cleavage of LPL in adipocytes, likely contributing to regulation of LPL in adipose tissue. Our data provide further support for an intracellular action of ANGPTL4 in adipocytes.

Quantified future challenges to sustainable food and nutrition security in the EU : Deliverable No. 10.2
Frank, S. ; Dijk, M. van; Havlik, P. ; Cui, David ; Heckelei, T. ; Kuiper, M.H. ; Latka, C. ; Witzke, H.P. ; Achterbosch, T.J. - \ 2018
SUSFANS - 44 p.
Leadership styles in two Ghanaian hospitals in a challenging environment
Aberese-Ako, Matilda ; Agyepong, Irene Akua ; DIjk, Han van - \ 2018
Health Policy and planning 33 (2018). - ISSN 0268-1080 - p. ii16 - ii26.
capacity - Context - frontline health worker - Ghana - hospital managers - leadership - low- and middle-income country - management - motivation

Hospital managers' power to exercise effective leadership in daily management can affect quality of care directly as well as through effects on frontline workers' motivation. This paper explores the influence of contextual factors on hospital managers' leadership styles and the motivation of frontline workers providing maternal and new born care in two public district hospitals in Ghana. It draws on data from an ethnographic study that involved participant observation, conversations and in-depth interviews conducted over 20 months, with frontline health workers and managers. Qualitative analysis software Nvivo 11 was used to facilitate coding, and common patterns emerging from the codes were grouped into themes. Ethical clearance was obtained from the Ghana Health Service Ethical Review Committee. Contextual factors such as institutional rules and regulations and funding constrained managers' power, and influenced leadership styles and responses to expressed and observed needs of frontline workers and clients. The contextual constraints on mangers' responses were a source of demotivation to both managers and frontline workers, as it hampered quality health service provision. Knowing what to do, but sometimes constrained by context, managers described 'feeling sick' and frustrated. On the other hand in the instances where managers' were able to get round the constraints and respond effectively to frontline health workers and clients' needs, they felt encouraged and motivated to work harder. Effective district hospital management and leadership is influenced by contextual factors; and not just individual manager's knowledge and skills. Interventions to strengthen management and leadership of public sector hospitals in low- and middle-income countries like Ghana need to consider context and not just individual managers' skills and knowledge strengthening.

Retirement concerns and planning of cooperative members : a study in the Dutch healthcare sector
Apostolakis, George ; Dijk, Gert van - \ 2018
Small Business Economics 53 (2018)4. - ISSN 0007-666X - p. 209 - 224.
Cooperatives - Healthcare - Retirement planning - Uncertainty

Retirement planning is a key component in achieving goals and fulfilling expectations. Although several socioeconomic and psychological factors associated with retirement planning have been reported in the literature, little is known about the influence that specific retirement-related issues have on retirement planning. We examine the influence of five concerns—the individual’s financial situation, living situation, care provision, health condition, and loneliness—on retirement planning. In addition, we investigate the influence of these concerns on individuals’ perceptions of their ideal post-retirement situations in terms of financial standards. Our dataset is derived from a 2010 web-based survey of the care and well-being sector in the Netherlands.

Omics analyses of potato plant materials using an improved one-class classification tool to identify aberrant compositional profiles in risk assessment procedures
Kok, Esther ; Dijk, Jeroen van; Voorhuijzen, Marleen ; Staats, Martijn ; Slot, Martijn ; Lommen, Arjen ; Venema, Dini ; Pla, Maria ; Corujo, Maria ; Barros, Eugenia ; Hutten, Ronald ; Jansen, Jeroen ; Voet, Hilko van der - \ 2018
Food Chemistry (2018). - ISSN 0308-8146
Compositional analysis - Genetically modified organism - GMO - Omics profiling - Risk assessment

The objective of this study was to quantitatively assess potato omics profiles of new varieties for meaningful differences from analogous profiles of commercial varieties through the SIMCA one-class classification model. Analytical profiles of nine commercial potato varieties, eleven experimental potato varieties, one GM potato variety that had acquired Phytophtora resistance based on a single insert with potato-derived DNA sequences, and its non-GM commercial counterpart were generated. The ten conventional varieties were used to construct the one-class model. Omics profiles from experimental non-GM and GM varieties were assessed using the one-class SIMCA models. No potential unintended effects were identified in the case of the GM variety. The model showed that varieties that were genetically more distant from the commercial varieties were recognized as aberrant, highlighting its potential in determining whether additional evaluation is required for the risk assessment of materials produced from any breeding technique, including genetic modification.

Afkeer van Roundup bemoeilijkt gevecht met onkruid
Dijk, Chris van - \ 2018
Joint assimilation of soil moisture retrieved from multiple passive microwave frequencies increases robustness of soil moisture state estimation
Gevaert, Anouk I. ; Renzullo, Luigi J. ; Dijk, Albert I.J.M. Van; Woerd, Hans J. Van Der; Weerts, Albrecht H. ; Jeu, Richard A.M. De - \ 2018
Hydrology and Earth System Sciences 22 (2018)9. - ISSN 1027-5606 - p. 4605 - 4619.
Soil moisture affects the partitioning of water and energy and is recognized as an essential climate variable. Soil moisture estimates derived from passive microwave remote sensing can improve model estimates through data assimilation, but the relative effectiveness of microwave retrievals in different frequencies is unclear. Land Parameter Retrieval Model (LPRM) satellite soil moisture derived from L-, C-, and X-band frequency remote sensing were assimilated in the Australian Water Resources Assessment landscape hydrology model (AWRA-L) using an ensemble Kalman filter approach. Two sets of experiments were performed. First, each retrieval was assimilated individually for comparison. Second, each possible combination of two retrievals was assimilated jointly. Results were evaluated against field-measured top-layer and root-zone soil moisture at 24 sites across Australia. Assimilation generally improved the coefficient of correlation (r) between modeled and field-measured soil moisture. L- and X-band retrievals were more informative than C-band retrievals, improving r by an average of 0.11 and 0.08 compared to 0.04, respectively. Although L-band retrievals were more informative for top-layer soil moisture in most cases, there were exceptions, and L- and X-band were equally informative for root-zone soil moisture. The consistency between L- and X-band retrievals suggests that they can substitute for each other, for example when transitioning between sensors and missions. Furthermore, joint assimilation of retrievals resulted in a model performance that was similar to or better than assimilating either retrieval individually. Comparison of model estimates obtained with global precipitation data and with higher-quality, higher-resolution regional data, respectively, demonstrated that precipitation data quality does determine the overall benefit that can be expected from assimilation. Further work is needed to assess the potentially complementary spatial information that can be derived from retrievals from different frequencies.
An environmental assessment of biorefining of rubber dandelion to rubber and bioplastic
Hingsamer, Maria ; Canella, Lorenza ; Jungmeier, Gerfried ; Meer, Ingrid van der; Dijk, Peter van; Muylle, Hilde ; Kirschner, Jan ; Kappen, Frans ; Gevers, Nico ; Hruschka, Steffen - \ 2018
In: 26th European Biomass Conference and Exhibition Proceedings. - Florence : ETA-Florence Renewable Energies (European Biomass Conference and Exhibition Proceedings ) - ISBN 9788889407189 - p. 1103 - 1105.
Biobased economy - Bioplastic - Biorefinery - Novel crop - Rubber
‘DRIVE4EU - Dandelion Rubber and Inulin Valorization and Exploitation for Europe’, a demonstration project, aims at the development of a value chain for natural rubber and inulin from Rubber dandelions. The objective of the project is to set up a new European chain for the production and processing of natural rubber. This will enable the EU to become less dependent on the import of natural rubber and at the same time to respond to the threat of a global rubber shortage. The viability of using Rubber dandelions for rubber and inulin for bioplastics (PEF – Polyethylene Furanoate) production depends on the sustainability of this new value chain. Within the project an environmental assessment using the methodology of Life Cycle Assessment (LCA) is performed. The aim is to identify, quantify and assess the most important environmental impacts and benefits of rubber and inulin from Rubber dandelion based on the whole value chain. Within the LCA scientific environmental indicators (e.g. global warming potential, cumulated primary energy demand, land use, water use, and acidification) will be used to guide the development of the DRIVE4EU value chain to realize the highest possible sustainability in comparison to a substituted reference system (natural rubber from Hevea tree and PET from fossil resources). The combination of natural rubber and inulin makes Rubber dandelion very interesting as a production platform.
Use of omics analytical methods in the study of genetically modified maize varieties tested in 90 days feeding trials
Corujo, Maria ; Pla, Maria ; Dijk, Jeroen van; Voorhuijzen, Marleen ; Staats, Martijn ; Slot, Martijn ; Lommen, Arjen ; Barros, Eugenia ; Nadal, Anna ; Puigdomènech, Pere ; Paz, José Luís La ; Voet, Hilko van der; Kok, Esther - \ 2018
Food Chemistry (2018). - ISSN 0308-8146
GMO (genetically modified organism) - Metabolomics - One-class model - Proteomics - Risk assessment - Transcriptomics

Genetically modified (GM) maize and their non-modified counterparts were compared using MON810 varieties, the only GMO event cultivated in Europe. The differences in grain samples were analysed by omics profiles, including transcriptomics, proteomics and metabolomics. Other cultivated maize varieties were analysed as a reference for the variability that will exist between cultivated varieties. The observed differences between modified and non-modified maize varieties do not exceed typical differences between non-modified varieties. The use of these advanced analytical approaches to analyse novel plant materials as compared to the results from animal feeding trials with whole foods is assessed. No indications were observed for changes in the GM varieties that warrant further investigations. Furthermore, it was shown that such indications will be obtained if maize samples of inferior quality are analysed similarly. Omics data provide detailed analytical information of the plant material, which facilitates a risk assessment procedure of new (GM) plant varieties.

Gemeente Rheden probeert Japanse duizendknoop te bestrijden
Dijk, Chris van - \ 2018
Predicting pension beneficiaries’ behaviour when offered a socially responsible and impact investment portfolio
Apostolakis, George ; Dijk, Gert van; Blomme, Robert J. ; Kraanen, Frido ; Papadopoulos, Athanasios P. - \ 2018
Journal of Sustainable Finance and Investment 8 (2018)3. - ISSN 2043-0795 - p. 213 - 241.
confidence - cooperatives - Impact investment - pension funds - perceived consumer effectiveness - social responsible investment - SRI - sustainable investment - TPB

In recent years, financial and demographic conditions, including low interest rates and volatile equity markets, have been testing the endurance of pension systems. Concern about the sustainability of pension systems has prompted discussion about introducing individual choices under the collective choice mandate. An ongoing discussion seeks to provide more freedom of choice and to shift towards a more individualized risk system within the collective mandate. This suggested individualization will increase operational costs but aims to keep pensions at current levels by shifting risk onto employees. Following the theory of planned behaviour (TPB), the objective of this paper is to examine pension beneficiaries’ intention to adopt a portfolio consisting of socially responsible and impact investments. We employ confirmatory factor and regression analyses to better understand pension beneficiaries’ attitudes, social norms, perceived consumer effectiveness, and intentions for such a choice. Responses from 637 respondents from a Dutch pension administrative organization were collected and identified as a valid sample. Consistent with the theory, the results of our analysis revealed that attitudes and social norms positively affected individuals’ intention to invest in this specific portfolio. Furthermore, we expand our model and incorporate perceived consumer effectiveness and consumer confidence as important factors influencing and moderating socially responsible behaviour, respectively. Our results imply that understanding the behavioural determinants affecting pension beneficiaries’ intentions can be an effective tool for increasing their involvement in pension affairs by making their own choices. Our findings yield policy recommendations for stimulating socially responsible investment behaviour in pension beneficiaries by examining the determinants of human behaviour.

Towards an explanatory framework for national level maternal health policy agenda item evolution in Ghana : An embedded case study
Koduah, Augustina ; Agyepong, Irene Akua ; Dijk, Han van - \ 2018
Health Research Policy and Systems 16 (2018)1. - ISSN 1478-4505
Decision pathway - Ghana - Maternal health - Policy actors - Policy agenda - Policy evolution - Policy fate - Power

Background: Understanding decision-making processes that influence the fate of items on the health policy agenda at national level in low- and middle-income countries is important because of the implications for programmes and outcomes. This paper seeks to advance our understanding of these processes by asking how and why maternal health policy agenda items have fared in Ghana between 1963 and 2014. Methods: The study design was a single case study of maternal health agenda evolution once on a decision pathway in Ghana, with three different agenda items as sub-units of analysis (fee exemptions for maternal health, free family planning and primary maternal health as part of a per capita provider payment system). Data analysis involved chronologically reconstructing how maternal health policy items evolved over time. Results: The fate of national level maternal health policy items was heavily influenced by how stakeholders (bureaucrats, professional bodies, general public and developmental partners) exercised power to put forward and advocate for specific ideas through processes of issues framing within a changing political and socioeconomic context. The evolution and fate of an agenda item once on a decision pathway involved an iterative process of interacting drivers shaping decisions through cycles of 'active' and 'static' pathways. Items could move from 'active' to 'static' pathways, depending on changing context and actor positions. Items that pursued the 'static' pathway in a particular cycle fell into obscurity by a process that could be described as a form of 'no decision made' in that an explicit decision was not taken to drop the item, but neither was any policy content agreed. Low political interest was exhibited and attempts to bring the item back into active decision-making were made by actors mainly in the bureaucratic arena seeking and struggling (unsuccessfully) to obtain financial and institutional support. Policy items that pursued 'active' pathways showed opposite characteristics and generally moved beyond agenda into formulation and implementation. Conclusion: Policy change requires sustaining policy agenda items into formulation and implementation. To do this, change agents need to understand and work within the relevant context, stakeholder interests, power, ideas and framing of issues.

DNA sequence and shape are predictive for meiotic crossovers throughout the plant kingdom
Demirci, Sevgin ; Peters, Sander A. ; Ridder, Dick de; Dijk, Aalt D.J. van - \ 2018
The Plant Journal 95 (2018)4. - ISSN 0960-7412 - p. 686 - 699.
Arabidopsis thaliana - crossover - DNA shape - genome accessibility - machine learning - maize - meiotic recombination - prediction - rice - tomato

A better understanding of genomic features influencing the location of meiotic crossovers (COs) in plant species is both of fundamental importance and of practical relevance for plant breeding. Using CO positions with sufficiently high resolution from four plant species [Arabidopsis thaliana, Solanum lycopersicum (tomato), Zea mays (maize) and Oryza sativa (rice)] we have trained machine-learning models to predict the susceptibility to CO formation. Our results show that CO occurrence within various plant genomes can be predicted by DNA sequence and shape features. Several features related to genome content and to genomic accessibility were consistently either positively or negatively related to COs in all four species. Other features were found as predictive only in specific species. Gene annotation-related features were especially predictive for maize, whereas in tomato and Arabidopsis propeller twist and helical twist (DNA shape features) and AT/TA dinucleotides were found to be the most important. In rice, high roll (another DNA shape feature) and low CA dinucleotide frequency in particular were found to be associated with CO occurrence. The accuracy of our models was sufficient for Arabidopsis and rice (area under receiver operating characteristic curve, AUROC > 0.5), and was high for tomato and maize (AUROC ≫ 0.5), demonstrating that DNA sequence and shape are predictive for meiotic COs throughout the plant kingdom.

Een exotisch monster
Dijk, Chris van - \ 2018
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