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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Breakthrough in Marine Invertebrate Cell Culture : Sponge Cells Divide Rapidly in Improved Nutrient Medium
Conkling, Megan ; Hesp, Kylie ; Munroe, Stephanie ; Sandoval, Kenneth ; Martens, Dirk E. ; Sipkema, Detmer ; Wijffels, Rene H. ; Pomponi, Shirley A. - \ 2019
Scientific Reports 9 (2019). - ISSN 2045-2322

Sponges (Phylum Porifera) are among the oldest Metazoa and considered critical to understanding animal evolution and development. They are also the most prolific source of marine-derived chemicals with pharmaceutical relevance. Cell lines are important tools for research in many disciplines, and have been established for many organisms, including freshwater and terrestrial invertebrates. Despite many efforts over multiple decades, there are still no cell lines for marine invertebrates. In this study, we report a breakthrough: we demonstrate that an amino acid-optimized nutrient medium stimulates rapid cell division in 9 sponge species. The fastest dividing cells doubled in less than 1 hour. Cultures of 3 species were subcultured from 3 to 5 times, with an average of 5.99 population doublings after subculturing, and a lifespan from 21 to 35 days. Our results form the basis for developing marine invertebrate cell models to better understand early animal evolution, determine the role of secondary metabolites, and predict the impact of climate change to coral reef community ecology. Furthermore, sponge cell lines can be used to scale-up production of sponge-derived chemicals for clinical trials and develop new drugs to combat cancer and other diseases.

Aflatoxin B1 in nixtamalized maize in Mexico; occurrence and accompanying risk assessment
Gilbert Sandoval, Ixchel ; Wesseling, Sebastiaan ; Rietjens, Ivonne M.C.M. - \ 2019
Toxicology Reports 6 (2019). - ISSN 2214-7500 - p. 1135 - 1142.
Aflatoxin B1 - Liver cancer - Maize - Margin of exposure (MOE) - Mexico - Risk assessment

Maize is a staple food in Mexico that might contain Aflatoxin B1 (AFB1). Nonetheless, data on the exposure and risk assessment of AFB1 from maize for the Mexican population are limited. The aim of the present study was to analyse the occurrence of AFB1 in Mexican nixtamalized maize samples, and to assess the accompanying exposure and risk. Four out of 88 samples contained AFB1 at levels above the limit of detection (1 ng/g). AFB1 occurrence values obtained in this study and additional occurrence values from literature were combined with available literature data for mean and P95 consumption of maize based products. For a 70 kg body weight person, lower bound and upper bound exposure assessments resulted in estimated daily intakes (EDI) of 0.7–8.5 ng/kg bw/day, based on a mean maize consumption. Based on the P95 maize consumption these EDI values amounted to 3.3–11.7 ng/kg bw/day. The corresponding Margin of Exposure (MOE) values amounted to 257-20 for the mean and 50-15 for the P95 consumers. The estimated increased cancer risks were 9-320 and 43-439 cases/106 individuals/lifetime of 75 years for the mean and P95 consumers, respectively. Altogether, the assessment reveals the need for continued risk management of AFB1 in Mexico.

Rarity of monodominance in hyperdiverse Amazonian forests
Steege, Hans Ter; Henkel, Terry W. ; Helal, Nora ; Marimon, Beatriz S. ; Marimon-Junior, Ben Hur ; Huth, Andreas ; Groeneveld, Jürgen ; Sabatier, Daniel ; Souza Coelho, Luiz de; Andrade Lima Filho, Diogenes de; Salomão, Rafael P. ; Amaral, Iêda Leão ; Almeida Matos, Francisca Dionízia de; Castilho, Carolina V. ; Phillips, Oliver L. ; Guevara, Juan Ernesto ; Jesus Veiga Carim, Marcelo de; Cárdenas López, Dairon ; Magnusson, William E. ; Wittmann, Florian ; Irume, Mariana Victória ; Martins, Maria Pires ; Silva Guimarães, José Renan da; Molino, Jean François ; Bánki, Olaf S. ; Piedade, Maria Teresa Fernandez ; Pitman, Nigel C.A. ; Mendoza, Abel Monteagudo ; Ramos, José Ferreira ; Luize, Bruno Garcia ; Moraes de Leão Novo, Evlyn Márcia ; Núñez Vargas, Percy ; Silva, Thiago Sanna Freire ; Venticinque, Eduardo Martins ; Manzatto, Angelo Gilberto ; Reis, Neidiane Farias Costa ; Terborgh, John ; Casula, Katia Regina ; Honorio Coronado, Euridice N. ; Montero, Juan Carlos ; Feldpausch, Ted R. ; Duque, Alvaro ; Costa, Flávia R.C. ; Arboleda, Nicolás Castaño ; Schöngart, Jochen ; Killeen, Timothy J. ; Vasquez, Rodolfo ; Mostacedo, Bonifacio ; Demarchi, Layon O. ; Assis, Rafael L. ; Baraloto, Chris ; Engel, Julien ; Petronelli, Pascal ; Castellanos, Hernán ; Medeiros, Marcelo Brilhante de; Quaresma, Adriano ; Simon, Marcelo Fragomeni ; Andrade, Ana ; Camargo, José Luís ; Laurance, Susan G.W. ; Laurance, William F. ; Rincón, Lorena M. ; Schietti, Juliana ; Sousa, Thaiane R. ; Sousa Farias, Emanuelle de; Lopes, Maria Aparecida ; Magalhães, José Leonardo Lima ; Mendonça Nascimento, Henrique Eduardo ; Lima de Queiroz, Helder ; Aymard C, Gerardo A. ; Brienen, Roel ; Revilla, Juan David Cardenas ; Vieira, Ima Célia Guimarães ; Cintra, Bruno Barçante Ladvocat ; Stevenson, Pablo R. ; Feitosa, Yuri Oliveira ; Duivenvoorden, Joost F. ; Mogollón, Hugo F. ; Araujo-Murakami, Alejandro ; Ferreira, Leandro Valle ; Lozada, José Rafael ; Comiskey, James A. ; Toledo, José Julio de; Damasco, Gabriel ; Dávila, Nállarett ; Draper, Freddie ; García-Villacorta, Roosevelt ; Lopes, Aline ; Vicentini, Alberto ; Alonso, Alfonso ; Dallmeier, Francisco ; Gomes, Vitor H.F. ; Lloyd, Jon ; Neill, David ; Aguiar, Daniel Praia Portela de; Arroyo, Luzmila ; Carvalho, Fernanda Antunes ; Souza, Fernanda Coelho de; Amaral, Dário Dantas do; Feeley, Kenneth J. ; Gribel, Rogerio ; Pansonato, Marcelo Petratti ; Barlow, Jos ; Berenguer, Erika ; Ferreira, Joice ; Fine, Paul V.A. ; Guedes, Marcelino Carneiro ; Jimenez, Eliana M. ; Licona, Juan Carlos ; Peñuela Mora, Maria Cristina ; Villa, Boris ; Cerón, Carlos ; Maas, Paul ; Silveira, Marcos ; Stropp, Juliana ; Thomas, Raquel ; Baker, Tim R. ; Daly, Doug ; Dexter, Kyle G. ; Huamantupa-Chuquimaco, Isau ; Milliken, William ; Pennington, Toby ; Ríos Paredes, Marcos ; Fuentes, Alfredo ; Klitgaard, Bente ; Pena, José Luis Marcelo ; Peres, Carlos A. ; Silman, Miles R. ; Tello, J.S. ; Chave, Jerome ; Cornejo Valverde, Fernando ; Fiore, Anthony Di; Hilário, Renato Richard ; Phillips, Juan Fernando ; Rivas-Torres, Gonzalo ; Andel, Tinde R. van; Hildebrand, Patricio von; Noronha, Janaína Costa ; Barbosa, Edelcilio Marques ; Barbosa, Flávia Rodrigues ; Matos Bonates, Luiz Carlos de; Sá Carpanedo, Rainiellen de; Dávila Doza, Hilda Paulette ; Fonty, Émile ; GómeZárate Z, Ricardo ; Gonzales, Therany ; Gallardo Gonzales, George Pepe ; Hoffman, Bruce ; Junqueira, André Braga ; Malhi, Yadvinder ; Andrade Miranda, Ires Paula de; Pinto, Linder Felipe Mozombite ; Prieto, Adriana ; Jesus Rodrigues, Domingos de; Rudas, Agustín ; Ruschel, Ademir R. ; Silva, Natalino ; Vela, César I.A. ; Vos, Vincent Antoine ; Zent, Egleé L. ; Zent, Stanford ; Weiss Albuquerque, Bianca ; Cano, Angela ; Carrero Márquez, Yrma Andreina ; Correa, Diego F. ; Costa, Janaina Barbosa Pedrosa ; Flores, Bernardo Monteiro ; Galbraith, David ; Holmgren, Milena ; Kalamandeen, Michelle ; Nascimento, Marcelo Trindade ; Oliveira, Alexandre A. ; Ramirez-Angulo, Hirma ; Rocha, Maira ; Scudeller, Veridiana Vizoni ; Sierra, Rodrigo ; Tirado, Milton ; Umaña Medina, Maria Natalia ; Heijden, Geertje van der; Vilanova Torre, Emilio ; Vriesendorp, Corine ; Wang, Ophelia ; Young, Kenneth R. ; Ahuite Reategui, Manuel Augusto ; Baider, Cláudia ; Balslev, Henrik ; Cárdenas, Sasha ; Casas, Luisa Fernanda ; Farfan-Rios, William ; Ferreira, Cid ; Linares-Palomino, Reynaldo ; Mendoza, Casimiro ; Mesones, Italo ; Torres-Lezama, Armando ; Giraldo, Ligia Estela Urrego ; Villarroel, Daniel ; Zagt, Roderick ; Alexiades, Miguel N. ; Oliveira, Edmar Almeida de; Garcia-Cabrera, Karina ; Hernandez, Lionel ; Palacios Cuenca, Walter ; Pansini, Susamar ; Pauletto, Daniela ; Ramirez Arevalo, Freddy ; Sampaio, Adeilza Felipe ; Valderrama Sandoval, Elvis H. ; Valenzuela Gamarra, Luis ; Levesley, Aurora ; Pickavance, Georgia ; Melgaço, Karina - \ 2019
Scientific Reports 9 (2019). - ISSN 2045-2322

Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors.

Excreta emissions in progeny of low and high enteric methane yield selection line sheep fed pasture of different qualities
Jonker, A. ; MacLean, S. ; Woyimo Woju, C. ; Garcia Rendon Calzada, M. ; Yu, W. ; Molano, G. ; Hickey, S. ; Pinares-Patiño, C.S. ; McEwan, J.C. ; Janssen, P.H. ; Sandoval, E. ; Lewis, S. ; Rowe, S. - \ 2019
Animal Feed Science and Technology 257 (2019). - ISSN 0377-8401
Animal variation - Breeding value - Greenhouse gas - Nitrous oxide - Repeatability - Urine

Selection of sheep with low enteric methane (CH4) emissions is a greenhouse gas (GHG) mitigation option suitable for pastoral systems. However, the effect of breeding sheep with low enteric CH4 emissions on excreta output and associated CH4 and nitrous oxide (N2O) emissions and therefore total GHG emissions are not known. The objective of the current experiments were to determine excreta output, and estimate associated GHG emissions, from progeny of low and high enteric CH4 per unit of dry matter intake (DMI) selection line sheep (CH4/DMI). The animals were fed two qualities of cut perennial ryegrass-based pasture (very mature vs. vegetative, 12 animals per CH4/DMI line) in Exp. 1 and cut pasture in two repeated seasons (autumn and winter; 15 animals per CH4/DMI line × 2 seasons) in Exp. 2. Total faecal and urine output was determined on individual animals, followed by enteric CH4 emission measurements in respiration chambers. GHG emissions from urine (N2O) and faeces (CH4 and N2O) were estimated based on New Zealand Agricultural GHG Inventory methodology. There was no interaction between CH4/DMI selection line and diet quality in Exp. 1 or seasons in Exp.2. Total daily faecal output of DM, organic matter (OM) and neutral detergent fibre (NDF; all g/d) and associated calculated faecal CH4 emissions were greater for low compared to high CH4/DMI sheep in Exp. 1 (P < 0.05), while being similar between CH4/DMI selection lines in Exp. 2. Nitrogen (N) excretion and N partitioning into urine, faeces and body retention, and calculated excreta N emissions, were mostly similar between CH4/DMI selection line sheep in both experiments. Except, faecal N output (g/d and per unit of N intake) and associated calculated direct faecal N2O-N emissions (g/d) were greater in low compared to high CH4/DMI sheep in Exp. 1 (P < 0.05). Enteric CH4 emissions were numerically 8% less (P = 0.15) in Exp.1 and 10% less (P = 0.004) in Exp. 2 and total animal level GHG emissions (CH4 and N2O) were numerically 7% less (P = 0.21) in Exp. 1 and 8% less (P = 0.006) in Exp.2 for progeny of the low compared to the high CH4/DMI line sheep. In conclusion, the magnitude of difference in enteric CH4 (expressed as CO2-equivalent) between low and high CH4/DMI selection line sheep were still present when CH4 from faeces and N2O emissions from urine and faeces were also accounted for. The animal genetic traits were expressed independent of environmental factors, i.e. pasture quality and season.

Genera of phytopathogenic fungi: GOPHY 3
Marin-Felix, Y. ; Hernández-Restrepo, M. ; Iturrieta-González, I. ; García, D. ; Gené, J. ; Groenewald, J.Z. ; Cai, L. ; Chen, Q. ; Quaedvlieg, W. ; Schumacher, R.K. ; Taylor, P.W.J. ; Ambers, C. ; Bonthond, G. ; Edwards, J. ; Krueger-Hadfield, S.A. ; Luangsa-ard, J.J. ; Morton, L. ; Moslemi, A. ; Sandoval-Denis, M. ; Tan, Y.P. ; Thangavel, R. ; Vaghefi, N. ; Cheewangkoon, R. ; Crous, P.W. - \ 2019
Studies in Mycology 94 (2019). - ISSN 0166-0616 - p. 1 - 124.
DNA barcodes - Fungal systematics - New taxa

This paper represents the third contribution in the Genera of Phytopathogenic Fungi (GOPHY) series. The series provides morphological descriptions, information about the pathology, distribution, hosts and disease symptoms for the treated genera, as well as primary and secondary DNA barcodes for the currently accepted species included in these. This third paper in the GOPHY series treats 21 genera of phytopathogenic fungi and their relatives including: Allophoma, Alternaria, Brunneosphaerella, Elsinoe, Exserohilum, Neosetophoma, Neostagonospora, Nothophoma, Parastagonospora, Phaeosphaeriopsis, Pleiocarpon, Pyrenophora, Ramichloridium, Seifertia, Seiridium, Septoriella, Setophoma, Stagonosporopsis, Stemphylium, Tubakia and Zasmidium. This study includes three new genera, 42 new species, 23 new combinations, four new names, and three typifications of older names.

Genetic algorithm as an optimization tool for the development of sponge cell culture media
Munroe, Stephanie ; Sandoval, Kenneth ; Martens, Dirk E. ; Sipkema, Detmer ; Pomponi, Shirley A. - \ 2019
In Vitro Cellular & Developmental Biology. Animal 55 (2019)3. - ISSN 1071-2690 - p. 149 - 158.
Cell culture - Dysidea etheria - Genetic algorithm - Medium optimization - Metabolic activity - Sponge

Sponges are rich sources of novel natural products. Production in cell cultures may be an option for supply of these compounds but there are currently no sponge cell lines. Because there is a lack of understanding about the precise conditions and nutritional requirements that are necessary to sustain sponge cells in vitro, there has yet to be a defined, sponge-specific nutrient medium. This study utilized a genetic algorithm approach to optimize the amino acid composition of a commercially available basal cell culture medium in order to increase the metabolic activity of cells of the marine sponge Dysidea etheria. Four generations of the algorithm were carried out in vitro in wet lab conditions and an optimal medium combination was selected for further evaluation. When compared to the basal medium control, there was a twofold increase in metabolic activity. The genetic algorithm approach can be used to optimize other components of culture media to efficiently optimize chosen parameters without the need for detailed knowledge on all possible interactions.

Seiridium (Sporocadaceae) : An important genus of plant pathogenic fungi
Bonthond, G. ; Sandoval-Denis, M. ; Groenewald, J.Z. ; Crous, P.W. - \ 2018
Persoonia 40 (2018)June. - ISSN 0031-5850 - p. 96 - 118.
Appendage-bearing conidia - Canker pathogen - Cupressus - Pestalotioid fungi - Systematics

The genus Seiridium includes multiple plant pathogenic fungi well-known as causal organisms of cankers on Cupressaceae. Taxonomically, the status of several species has been a topic of debate, as the phylogeny of the genus remains unresolved and authentic ex-type cultures are mostly absent. In the present study, a large collection of Seiridium cultures and specimens from the CBS and IMI collections was investigated morphologically and phylogenetically to resolve the taxonomy of the genus. These investigations included the type material of the most important Cupressaceae pathogens, Seiridium cardinale, S. cupressi and S. unicorne. We constructed a phylogeny of Seiridium based on four loci, namely the ITS rDNA region, and partial translation elongation factor 1-alpha (TEF), β-tubulin (TUB) and RNA polymerase II core subunit (RPB2). Based on these results we were able to confirm that S. unicorne and S. cupressi represent different species. In addition, five new Seiridium species were described, S. cupressi was lectotypified and epitypes were selected for S. cupressi and S. eucalypti.

Managing the interactions between soil abiotic factors to alleviate the effect of Fusarium wilt in bananas
Segura, R.A. ; Stoorvogel, J.J. ; Samuels, J.Z. ; Sandoval, J.A. - \ 2018
In: 10th International Symposium on Banana. - International Society for Horticultural Science (Acta Horticulturae ) - ISBN 9789462611924 - p. 163 - 168.
Biomass - Micronutrients - Panama disease - Plant disease - Soil fertility
Soil management offers various options to alleviate the effects of Fusarium wilt caused by Fusarium oxysporum f. sp. cubense (Foc) in bananas. Nevertheless, it receives little attention as a strategy in Fusarium wilt management. Literature provides ample evidence linking soil conditions such as soil texture and fertility to the spread and severity of plant diseases. However, the inconsistency of results between case studies limits the attention of soil management in crop disease management. The present study aimed at unravelling the role of soil abiotic factors on nutrient concentrations in plant tissue, biomass production and the incidence of Fusarium wilt (Foc race 1) in bananas (‘Gros Michel’, AAA) under field conditions. A large field trial was established in which the effects of soil pH and nutrients (N, Ca, Mg and Mn) were studied. Around 30% of the plants showed symptoms of Fusarium wilt at flowering in the first season. However, Fusarium wilt incidence did not vary between treatments. Soil pH showed significant interactions with soil N and Mn concentrations resulting in a lower bunch weight and increased micronutrient concentrations in the pseudostem. With a higher pH, bunch weight increased, although higher Mn concentrations suppressed this positive effect. Interactions between a high soil pH and Ca and Mg resulted in a higher bunch weight and lower micronutrient concentrations in the pseudostem. The results can be used to develop soil management strategies for improving banana productivity in infected plantations.
Designing hybrid learning configurations at the interface between school and workplace
Cremers, P.H.M. - \ 2016
Wageningen University. Promotor(en): Martin Mulder; Arjen Wals, co-promotor(en): Renate Wesselink. - Wageningen : Wageningen University - ISBN 9789462576322 - 156
intermediate vocational training - education - education programmes - higher education - organization of education - practical education - postsecondary education - vocational training - firms - companies - knowledge transfer - knowledge - netherlands - middelbaar beroepsonderwijs - onderwijs - onderwijsprogramma's - hoger onderwijs - onderwijsorganisatie - praktijkonderwijs - vervolgonderwijs - beroepsopleiding - firma's - kapitaalvennootschappen - kennisoverdracht - kennis - nederland

In today’s knowledge society there is a demand for professionals who are able to create knowledge across boundaries of disciplines, professions and perspectives. Increasingly, challenges have to be addressed by experts from different fields who collaborate across different contexts. In addition, given the fast pace with which society changes, experts must continually construct and reconstruct their expertise in a process of lifelong learning. Institutions for higher and vocational education are challenged to educate these ‘knowledge workers’. They are responding, among others, by developing novel hybrid practices at the interface between school and workplace, the so-called hybrid learning configurations. By connecting education, research and professional practice they aim to address complex problems in society by fostering interprofessional collaboration and learning. We define a hybrid learning configuration (HLC) as ‘a social practice around illdefined, authentic tasks or issues whose resolution requires transboundary learning by transcending disciplines, traditional structures and sectors, and forms of learning’.

While many educational institutions and other organizations are co-developing and experimenting with HLCs, the process followed is often one of trial and error. Practical expertise is becoming available but only in an ad hoc and fragmented way. Although research on situated and social learning offers relevant theories and concepts that are useful when designing an HLC, not much research has addressed the design of HLCs in a comprehensive way. This PhD research aims to address this lacuna. We investigate HLCs from an educational design research (EDR) perspective, which involves framing the HLC as a complex intervention. We are interested not only in the features or designed elements of such interventions, but also in the underlying principles or conjectures that are embodied in those features. In addition, we intend to provide support for interprofessional HLC design teams, which consist of, for instance, educational consultants, researchers, lecturers and other practitioners. In order to address these aims we studied six HLCs in the context of Dutch higher vocational education. One of the cases is a joint project of two Dutch institutions for senior secondary vocational educational (which are called ‘MBO’ in Dutch) and two universities of applied sciences (‘HBO’ in Dutch) in collaboration with two companies. The other cases are HLCs in different settings within the context of a university of applied sciences in the Netherlands.

The aims mentioned above led to the following general research questions: 1. Which heuristics can underpin the design of a hybrid learning configuration? 2. In which ways can interprofessional teams be supported when designing hybrid learning configurations? Chapters 2 and 3 address the first research question and chapters 4 and 5 address the second question.

Design principles for HLCs

Chapter 2 focuses on the HLC as a whole. The central research question is: “Which set of principles can underpin the design of a hybrid learning configuration for educating the knowledge worker?” Based on a literature search and designers’ craft knowledge, a set of initial design principles was developed for an HLC at the interface between school and workplace. The intention was that four learning processes would be enabled by the HLC: self-directed learning, authentic learning, the development of a professional identity and collaborative creation of knowledge across the boundaries of disciplines, professions and perspectives.

These initial design principles were evaluated from the perspective of the participants by analysing interview data from students, lecturers, educational consultants and business representatives. This resulted in the following set of seven refined principles that underpin the design of an HLC: fostering authenticity; creating a learning community; utilizing diversity; inter-linking of working and learning; facilitating reflexivity; enabling organization; enabling ecology. These principles can be used as heuristics for guiding the design and development of hybrid learning configurations in contexts that have similar goals and aligned tenets.

Fostering self-directed lifelong learning in HLCs

Chapter 3 elaborates further on the design principle ‘facilitating reflexivity’. Since knowledge workers have to redefine and reconstruct their own expertise in an on-going fashion, they should be able to reflect on and pro-actively develop their professional competence. This capacity for self-directed lifelong learning is an essential asset for them and should therefore be developed or enhanced in an HLC. The main research question in this chapter is: “Which design guidelines underpin an intervention that would foster students’ capacity for self-directed lifelong learning while working on ill-structured, authentic professional tasks?”

An intervention was designed, implemented and evaluated during two iterations of a hybrid learning configuration, which was embedded in a one-semester elective course at a university of applied sciences in the Netherlands. Evaluation methods included interviews with students and the course facilitator, questionnaires, and students’ logs and reports. This resulted in the following five intervention design guidelines: provide opportunities to engage in two or more cycles of self-directed learning; provide educational support; pay attention to emotional and motivational aspects; treat self-directed lifelong learning as a social learning process; position self-directed lifelong learning as a self-evident and integrated part of the course.

The intervention appeared to be usable and effective. At a basic level, the students developed their capacity for self-directed lifelong learning. We concluded that further research is needed to investigate conditions for realizing higher levels of proficiency in self-directed lifelong learning throughout the curriculum and beyond.

Utilization of design principles for HLCs

The focus of chapter 4 is the utilization of the set of design principles that was generated in chapter 2. Research has shown that while knowledge of design heuristics can increase the efficiency and effectiveness of design work, design teams often have difficulty articulating the rationale for their design. In addition, it is important to facilitate ideation and nourish creative spirit while utilizing the design heuristics to create a novel learning environment. In this study we explored an intervention for supporting the creative utilization of the set of design principles for HLC. The intervention was based on boundary-crossing theory and design thinking methods, with a particular focus on prototyping. It consisted of a ‘guidebook’ in which the design principles were explained, and a workshop. The corresponding research question was: “What is the perceived effectiveness of a boundarycrossing intervention (based on a set of research-based design principles) for (re)designing hybrid learning configurations?”

Four design teams of different HLCs in the context of a university of applied sciences used the guidebook and attended the workshop while (re)designing their HLC. The intervention was evaluated by way of questionnaires that were filled out by members of the design teams. The results show that the design teams perceived this intervention as being relevant, consistent, practical and effective. The intervention appeared to provide a conceptual framework for understanding and designing features of a hybrid learning configuration and a vocabulary to communicate design ideas. It, thereby, supported the creative utilization of the design principles. Further research could explore other, complementary ways of facilitating the design of hybrid learning configurations.

Cross-boundary learning during the design and implementation of an HLC

Chapter 5 concerns cross-boundary collaboration and learning processes within an interprofessional design team of an HLC. These teams often consist of actors from different educational institutions and other organizations, such as companies or (non) governmental institutions. When team members bring their different perspectives into the collaboration, they are likely to experience boundaries. Boundaries can be defined as ‘discontinuities in action or interaction’. They can hinder cooperation, but they can also provide opportunities for learning. This led to the following research question: “In which ways could a better understanding of boundaries enhance learning?”

In this study, transcripts of interviews with members of an HLC-design team were analysed using concepts of boundary crossing theory. This theoretical framework provided a lens through which different ways of boundary crossing, learning mechanisms and processes became visible. We established that boundaries are highly personal and subjective constructs. We found that if boundaries are detected and if the related practices are made explicit, this allows for further analysis of these boundaries. Our analysis yielded a number of possible ways to enhance trans-boundary learning in HLC design teams. We also concluded that boundary objects and brokers can play an important role in transboundary learning processes.

Conclusions in a broader perspective

In chapter 6 we frame our conclusions from the four studies in a broader perspective. The first aim of our research was the development of heuristics for the design of HLCs. Given this aim, we developed a set of design principles for an HLC and guidelines for an intervention that fosters the capacity for self-directed lifelong learning. We positioned these principles and guidelines in a ‘conjecture map’ (Sandoval 2014), which shows the relationships between design heuristics, their embodiment in features of an intervention, the intended mediating processes, and the desired outcomes. Our overall conclusion is that framing the set of design principles or guidelines in multiple conjecture maps, rather than representing them as causal chains of design propositions, can provide guidance and support for designing and researching complex educational interventions such as HLCs.

Our second aim was to provide support or ‘design knowledge’ for interprofessional HLC design teams. We addressed that aim by developing and testing an intervention that supported the creative utilization of a set of design principles for HLC. In addition, we provided guidance for enhancing learning across boundaries that could be experienced in an interprofessional design team. We positioned this design knowledge in a broader framework, the ‘ecological framework for conceptualizing teacher knowledge for technology-enhanced learning design’. This framework seems to be useful in contexts beyond technology-enhanced learning, and, so, we consider it relevant to the design of HLCs. We conclude that design teams of HLCs can be supported by using an appropriate framework for design knowledge and by adjusting or expanding this framework for the design of complex interventions by interprofessional design teams.

Further research and practical implications

Our studies led us to the following recommendations. While we focused mainly on learning processes that should occur within HLCs, further research could be directed towards the students’ learning outcomes. Moreover, our findings suggest that selfdirected lifelong learning should be developed and practiced throughout an education programme. To achieve this, curricula in higher education should offer opportunities for students to experiment and follow their own path, alongside prescribed activities with fixed learning outcomes. In the six HLCs that we studied, student learning was foregrounded. However, an HLC also involves other stakeholder types, such as lecturers, researchers, citizens, and entrepreneurs. Therefore, further research could shed light on supporting and evaluating multi-stakeholder learning processes and learning outcomes of all types of stakeholders. Our research on supporting interprofessional design teams focused on the utilization of design knowledge in early stages of (re)design of an HLC. Further research and development could yield ways of support in further stages of the design. In light of this we recommend crossing the boundaries of areas of design science outside the educational context. This will allow us to learn from each other and capitalize on what is already known.

In our study, design principles for HLC were ‘reified’ and disseminated by way of a guidebook. Further investigations could reveal other ways of documenting and communicating design knowledge, for instance via the construction of a database containing principles or guidelines and their associated features in different contexts. Boundary crossing theory appeared to provide a lens through which boundaries and related learning processes became visible. The elements of boundary crossing theory can be translated into guidelines or tools for enhancing cross-boundary learning in interprofessional HLC design teams and, perhaps, for other types of ‘hybrid teams’ as well.

This thesis intends to contribute to the knowledge base for designing hybrid learning configurations. This is done with the intention that this contribution will be utilized and developed further by researchers and practitioners who are committed to educating future professionals in an ever-changing world.

Chemical and microbiological interactions between soils and roots in commercial banana plantations (Musa AAA, cv. Cavendish)
Segura Mena, R. ; Serrano, E. ; Pocasangre, L. ; Acuna, O. ; Bertsch, F. ; Stoorvogel, J.J. ; Sandoval, J.A. - \ 2015
Scientia Horticulturae 197 (2015). - ISSN 0304-4238 - p. 66 - 71.
A study was performed to determine the relationships between soil chemical and microbiological con-ditions and how they impact soil production. The study was carried out on six Costa Rican commercialbanana farms with high, medium and low productivity. In each of the farms sector with relatively goodand poor crop development were identified. In these sectors, microbiological and chemical properties ofthe soil and banana roots were characterized in the fertilization band, the interrow, and the rhizosphere. Inaddition, crop performance was evaluated in terms of plant height, the vigour of the pseudostem, and thenumber of hands per bunch. Higher biometric values were found in the sectors with good development,regardless of the farm, than in those with poor plant development. The pH was significantly lower in thesectors with poor crop performance in both the fertilization band and the rhizosphere. The soil chemicaland microbiological properties differed significantly between the good and poor performing areas, butalso between the fertilization band, interrow, and rhizosphere. Bacteria, fungi and actinomycetes wereless in roots from plants in the sectors with poor performance. Chemical and microbiological conditionsin the soil influenced the roots conditions according with the banana plant development and production.This study shows the complex interactions between soil chemical and microbiological conditions andhow they affect banana production.
Soil management as an effective strategy for crop disease management: the case of panama disease in banana
Segura Mena, R. ; Stoorvogel, J.J. ; Garcia-Bastidas, F. ; Salacinas-Niez, M. ; Sandoval, J.A. ; Kema, G. - \ 2015
In: Book of Abstract of the Wageningen Soil Conference: Soil Science in a Changing World. - - p. 48 - 48.
Crop diseases are an important threat to food security. Crop disease management includes a range of different options, such as breeding for resistance, which is attractive but relatively slow, and chemical control, which may be effective but can have adverse environmental impacts. There is an increased awareness that optimal crop disease management is a combination of different approaches. An option that receives relatively little attention is soil management, which may influence disease incidence. The effects of soil abiotic factors such as pH and N-content on the incidence of diseases in different crops have been reported. In this study we test the hypothesis that optimal soil conditions may help to suppress the predisposition of banana to Panama disease (a soil born fungal disease caused by Fusarium oxysporum f.sp. cubense). Although deficiencies can predispose the plant to present diseases, an excessive level of nutrients can also influence disease incidence or severity. In order to validate the model, we tested the effect of soil pH and nitrogen level on Panama disease in greenhouse trials. Inoculated and non-inoculated banana plants were planted in a soil with two pH and three nitrogen levels. Low pH and nitrogen levels showed a significant higher incidence of Panama disease. Results show that soil abiotic factors do contribute to disease management in crops. Besides, practices as liming to increase the soil pH should be tested as an option to slow down the incidence and reduce the severity of Panama disease in infested areas. Also the application of adequate doses of N contributes to disease management. In field and on-farm trials are planned to substantiate these data demonstrating the role of soil abiotic factors on Panama disease incidence and severity in banana.
Deciphering microbial landscapes of fish eggs to mitigate emerging diseases
Liu, Y. ; Bruijn, I. de; Jack, A.L.H. ; Drynan, K. ; Berg, A.H. van den; Thoen, E. ; Sandoval-Sierra, V. ; Skaar, I. ; West, P. van; Diéguez-Uribeondo, J. ; Voort, M. van der; Mendez, R. ; Mazzola, M. ; Raaijmakers, J.M. - \ 2014
ISME Journal 8 (2014). - ISSN 1751-7362 - p. 2002 - 2014.
saprolegnia-parasitica - rhizosphere microbiome - aphanomyces-invadans - virulence factors - maternal transfer - wild populations - sp nov. - fungi - bacteria - molds
Animals and plants are increasingly suffering from diseases caused by fungi and oomycetes. These emerging pathogens are now recognized as a global threat to biodiversity and food security. Among oomycetes, Saprolegnia species cause significant declines in fish and amphibian populations. Fish eggs have an immature adaptive immune system and depend on nonspecific innate defences to ward off pathogens. Here, meta-taxonomic analyses revealed that Atlantic salmon eggs are home to diverse fungal, oomycete and bacterial communities. Although virulent Saprolegnia isolates were found in all salmon egg samples, a low incidence of Saprolegniosis was strongly correlated with a high richness and abundance of specific commensal Actinobacteria, with the genus Frondihabitans (Microbacteriaceae) effectively inhibiting attachment of Saprolegniato salmon eggs. These results highlight that fundamental insights into microbial landscapes of fish eggs may provide new sustainable means to mitigate emerging diseases.
Assessment of the development of aquifer management councils (COTAS) for sustainable groundwater management in Guanajuato, Mexico
Wester, P. ; Sandoval Minero, R. ; Hoogesteger van Dijk, J.D. - \ 2011
Hydrogeology Journal 19 (2011)4. - ISSN 1431-2174 - p. 889 - 899.
user associations - governance - challenges - issues - institutions - countries - policies - states - india
Collective groundwater management by water users—self-regulation—is increasingly advocated as a complement to state regulation. This article analyzes the attempts by the Guanajuato State Water Commission (CEAG) in central Mexico to promote user self-regulation through the establishment and development of 14 Consejos Técnicos de Aguas (COTAS; Technical Water Councils). Based on a joint assessment by a former senior CEAG policy-maker and two researchers, Guanajuato’s groundwater-management policy is reviewed to understand why user self-regulation was less successful than expected. It concludes that increasing awareness and improving the knowledge base on groundwater is not enough to trigger self-regulation by groundwater users. A wider delegation of responsibilities to the COTAS is necessary, combined with: (1) functioning mechanisms for enforcing groundwater legislation, especially concerning well permits and pumped volumes, and (2) mechanisms that ensure the legitimacy and accountability of users’ representatives to both users and state agencies
"Nothing without the users": A reassessment of the development of Aquifer Management Councils (COTAS) for sustainable groundwater management in Guanajuato, Mexico
Wester, P. ; Sandoval-Minero, R. ; Hoogesteger van Dijk, J.D. - \ 2008
Quantitative resistance and its components in 16 barley cultivars to yellow rust, Puccinia striiformis f.sp. hordei
Sandoval-Islas, J.S. ; Broers, L.H.M. ; Mora-Aguilera, G. ; Parlevliet, J.E. ; Osada-Kawasoe, S. ; Vivar, H.E. - \ 2007
Euphytica 153 (2007)3. - ISSN 0014-2336 - p. 295 - 308.
wheat leaf rust - adult-plant resistance - stripe rust - spring wheat - development stage - latent period - growth stages - epidemics
Sixteen barley cultivars with a susceptible infection type (IT = 7-8) in the seedling stage to an isolate of race 24 of Puccinia striiformis f. sp. hordei were planted at two locations in México. Disease severity (DS) parameters were assessed for the flag leaf and for the upper three leaves. The cultivars represented at least five levels of quantitative resistance ranging from very susceptible to quite resistant. ¿Granado¿, ¿Gloria/Copal¿ and ¿Calicuchima-92¿ represented the most resistant group and had an IT of 7 or 8. The cultivar × environment interaction variance, although significant, was very small compared with the cultivar variance. The disease severity parameters were highly correlated. The monocyclic parameter DSm, measured when the most susceptible cultivar had reached its maximum DS, was very highly correlated with the area under the disease progress curve (AUDPC), r being 0.98. Components of quantitative resistance were evaluated in two plant stages. In the seedling stage small cultivar effects for the latency period were observed, which were not correlated with the quantitative resistance measured in the field. In the adult plant stage the latency period (LP), infection frequency (IF) and colonization rate (CR) were measured in the upper two leaves. The LP was much longer than in the seedling stage and differed strongly between cultivars. The differences in IF were too large, those in CR varied much less. The components showed association with one another. The LP and IF were well correlated with the AUDPC (r = 0.7-0.8).
Combining in vitro data and modelling to predict in vivo animal response
Dijkstra, J. ; France, J. - \ 2006
In: Herbivores: the Assessment of Intake, Digestibility and the Roles of Secondary Compounds / Sandoval-Castro, C.A., Hovell, F.D. DeB., Torres-Acosta, J.F.J., Ayala-Burgos, A., Nottingham : Nottingham University Press - ISBN 1904761526 - p. 135 - 144.
The importance of silvopastoral system in rural livelihoods to provide ecosystem services
Mannetje, L. t; Ramirez, L. ; Ibrahim, M. ; Sandoval, C. ; Ojeda, N. ; Ku, J. - \ 2004
Mérida : Autonomous University of Yucatan - 346
silvopastorale systemen - agroforestrysystemen - vee - biodiversiteit - milieueffect - levensstandaarden - latijns-amerika - agro-ecosystemen - ecosysteemdiensten - silvopastoral systems - agroforestry systems - livestock - biodiversity - environmental impact - living standards - latin america - agroecosystems - ecosystem services
Matching herbivore nutrition to ecosystems biodiversity: proceedings of an International Symposium
Mannetje, L. t; Ramirez-Aviles, L. ; Sandoval-Castro, C. ; Ku-Vera, J.C. - \ 2003
Merida, Yucatan, Mexico : Autonomous University of Yucatan - ISBN 9706980431 - 341
diervoeding - herbivoren - metabolisme - spijsverteringsstelsel - voeropname - latijns-amerika - animal nutrition - herbivores - metabolism - digestive system - feed intake - latin america
Predicting the yield of nutrients from microbial metabolism in the rumen
Dijkstra, J. ; Tamminga, S. ; Mills, J.A.N. - \ 2003
In: Matching Herbivore Nutrition to Ecosystems Biodiversity. Proceedings of the VIth International Symposium on the Nutrition of Herbivores / t' Mannetje, L., Ramiréz-Avilés, L., Sandoval-Castro, C.A., Ku-Vera, J.C., Mérida, Mexico : - p. 101 - 127.
Cattle grazing preference between two cultivars of perennial ryegrass
Smit, H.J. ; Akker, C. van den; Galle, J. ; Tas, B.M. ; Taweel, H.Z. ; Elgersma, A. - \ 2003
In: Matching herbivore nutrition to ecosystems biodiversity. - Mexico : Autonomous University of Yucatan - p. 449 - 452.
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