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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Root stem cell niche organizer specification by molecular convergence of PLETHORA and SCARECROW transcription factor modules
Shimotohno, Akie ; Heidstra, Renze ; Blilou, Ikram ; Scheres, Ben - \ 2018
Genes and Development 32 (2018)15-16. - ISSN 0890-9369 - p. 1085 - 1100.
Arabidopsis - Organizer - PLT-TCP-SCR complexes - Quiescent center - Stem cell niche - WUSCHEL-RELATED HOMEOBOX 5

Continuous formation of somatic tissues in plants requires functional stem cell niches where undifferentiated cells are maintained. In Arabidopsis thaliana, PLETHORA (PLT) and SCARECROW (SCR) genes are outputs of apical– basal and radial patterning systems, and both are required for root stem cell specification and maintenance. The WUSCHEL-RELATED HOMEOBOX 5 (WOX5) gene is specifically expressed in and required for functions of a small group of root stem cell organizer cells, also called the quiescent center (QC). PLT and SCR are required for QC function, and their expression overlaps in the QC; however, how they specify the organizer has remained unknown. We show that PLT and SCR genetically and physically interact with plant-specific teosinte-branched cycloidea PCNA (TCP) transcription factors to specify the stem cell niche during embryogenesis and maintain organizer cells post-embryonically. PLT–TCP–SCR complexes converge on PLT-binding sites in the WOX5 promoter to induce expression.

Mitochondrial dynamics in cancer-induced cachexia
Ende, Miranda van der; Grefte, Sander ; Plas, Rogier ; Meijerink, Jocelijn ; Witkamp, Renger F. ; Keijer, Jaap ; Norren, Klaske van - \ 2018
- p. 137 - 150.
Animal models - Cancer-induced cachexia - Mitochondria - Mitochondrial dynamics - Muscle

Cancer-induced cachexia has a negative impact on quality of life and adversely affects therapeutic outcomes and survival rates. It is characterized by, often severe, loss of muscle, with or without loss of fat mass. Insight in the pathophysiology of this complex metabolic syndrome and direct treatment options are still limited, which creates a research demand. Results from recent studies point towards a significant involvement of muscle mitochondrial networks. However, data are scattered and a comprehensive overview is lacking. This paper aims to fill existing knowledge gaps by integrating published data sets on muscle protein or gene expression from cancer-induced cachexia animal models. To this end, a database was compiled from 94 research papers, comprising 11 different rodent models. This was combined with four genome-wide transcriptome datasets of cancer-induced cachexia rodent models. Analysis showed that the expression of genes involved in mitochondrial fusion, fission, ATP production and mitochondrial density is decreased, while that of genes involved ROS detoxification and mitophagy is increased. Our results underline the relevance of including post-translational modifications of key proteins involved in mitochondrial functioning in future studies on cancer-induced cachexia.

Trusting Former Rebels : An Experimental Approach to Understanding Reintegration after Civil War
Bauer, Michal ; Fiala, Nathan ; Levely, Ian - \ 2018
Economic Journal 128 (2018)613. - ISSN 0013-0133 - p. 1786 - 1819.

The stability of many post-conflict societies rests on the successful reintegration of former soldiers. We use a set of behavioural experiments to study the effects of forced military service for a rebel group (the Lord's Resistance Army) on trust and trustworthiness in Northern Uganda. We present evidence that soldiers did not self-select nor were systematically screened by rebels. We find that the experience of soldiering increases individual trustworthiness and community engagement, especially among those who soldiered during early age. These results suggest that the impact of child soldiering on social behaviour is not necessarily detrimental.

Altered neural responsivity to food cues in relation to food preferences, but not appetite-related hormone concentrations after RYGB-surgery
Zoon, Harriët F.A. ; Bruijn, Suzanne E.M. de; Smeets, Paul A.M. ; Graaf, Cees de; Janssen, Ignace M.C. ; Schijns, Wendy ; Aarts, Edo O. ; Jager, Gerry ; Boesveldt, Sanne - \ 2018
Behavioural Brain Research 353 (2018). - ISSN 0166-4328 - p. 194 - 202.
Endocannabinoid - Energy-density - fMRI - Food cues - Ghrelin - Obesity - Olfactory - Reward - Roux-en-Y gastric bypass surgery - Visual

Background: After Roux-en-Y gastric bypass (RYGB) surgery, patients report a shift in food preferences away from high-energy foods. Objective: We aimed to elucidate the potential mechanisms underlying this shift in food preferences by assessing changes in neural responses to food pictures and odors before and after RYGB. Additionally, we investigated whether altered neural responsivity was associated with changes in plasma endocannabinoid and ghrelin concentrations. Design: 19 RYGB patients (4 men; age 41 ± 10 years; BMI 41 ± 1 kg/m2 before; BMI 36 ± 1 kg/m2 after) participated in this study. Before and two months after RYGB surgery, they rated their food preferences using the Macronutrient and Taste Preference Ranking Task and BOLD fMRI responses towards pictures and odors of high-, and low-energy foods and non-food items were measured. Blood samples were taken to determine plasma endocannabinoid and ghrelin concentrations pre- and post-surgery. Results: Patients demonstrated a shift in food preferences away from high-fat/sweet and towards low-energy/savory food products, which correlated with decreased superior parietal lobule responsivity to high-energy food odor and a reduced difference in precuneus responsivity to high-energy versus low-energy food pictures. In the anteroventral prefrontal cortex (superior frontal gyrus) the difference in deactivation towards high-energy versus non-food odors reduced. The precuneus was less deactivated in response to all cues. Plasma concentrations of anandamide were higher after surgery, while plasma concentrations of other endocannabinoids and ghrelin did not change. Alterations in appetite-related hormone concentrations did not correlate with changes in neural responsivity. Conclusions: RYGB leads to changed responsivity of the frontoparietal control network that orchestrates top-down control to high-energy food compared to low-energy food and non-food cues, rather than in reward related brain regions, in a satiated state. Together with correlations with the shift in food preference from high- to low-energy foods this indicates a possible role in new food preference formation.

Hox gene expression profiles during embryonic development of common sole
Kavouras, Menelaos ; Malandrakis, Emmanouil E. ; Golomazou, Eleni ; Konstantinidis, Ioannis ; Blom, Ewout ; Palstra, Arjan P. ; Anastassiadis, Konstantinos ; Panagiotaki, Panagiota ; Exadactylos, Athanasios - \ 2018
Animal Biology (2018). - ISSN 1570-7555 - 16 p.
Broodstock - egg quality - homeobox genes - reproduction - Solea solea
Common sole (Solea solea) aquaculture production is based mostly on wild-caught breeders. Recently, the successful reproduction of first-generation fish that were reared in captivity was accomplished. A consistent good quality and quantity of produced eggs throughout the year, and of next-generation
broodstock, is important for reducing the overall cost of production. Hox genes play a pivotal role in normal embryonic development and alterations of their temporal expression level may be important for egg viability. Expression profile analysis of five hox genes (hoxa1a, hoxa2a, hoxa2b, hoxb1a and hoxb1b) involved in early embryonic development and of hoxa13a, which is involved in late stages, was carried out. Results revealed a premature and/or maternal expression of hoxa13a in sole embryos,and the detection of hoxa2a and hoxa2b genes as members of paralog group 2. Principal Component Analysis of hox gene expression in 54 ± 6 hours post fertilization embryos coming from wild-caught broodstock and a first-generation one reared in the hatchery, unveiled that these broodstocks are clearly distinct. In addition, their pairwise comparison revealed significant differences in the expression levels of hoxb1a and hoxb1b genes. Hox gene regulation during embryonic development could give valuable
insight into rearing sole broodstocks with different origin in concert, and also into gaining a steady mass production of eggs, either in quality or quantity, all year round.
Arabidopsis thaliana ambient temperature responsive lncRNAs
Severing, Edouard ; Faino, Luigi ; Jamge, Suraj ; Busscher, Marco ; Kuijer-Zhang, Yang ; Bellinazzo, Francesca ; Busscher-Lange, Jacqueline ; Fernández, Virginia ; Angenent, Gerco C. ; Immink, Richard G.H. ; Pajoro, Alice - \ 2018
BMC Plant Biology 18 (2018)1. - ISSN 1471-2229
Ambient temperature response - Arabidopsis thaliana - FLINC - Flowering time - Long non-coding RNA (lncRNA)

Background: Long non-coding RNAs (lncRNAs) have emerged as new class of regulatory molecules in animals where they regulate gene expression at transcriptional and post-transcriptional level. Recent studies also identified lncRNAs in plant genomes, revealing a new level of transcriptional complexity in plants. Thousands of lncRNAs have been predicted in the Arabidopsis thaliana genome, but only a few have been studied in depth. Results: Here we report the identification of Arabidopsis lncRNAs that are expressed during the vegetative stage of development in either the shoot apical meristem or in leaves. We found that hundreds of lncRNAs are expressed in these tissues, of which 50 show differential expression upon an increase in ambient temperature. One of these lncRNAs, FLINC, is down-regulated at higher ambient temperature and affects ambient temperature-mediated flowering in Arabidopsis. Conclusion: A number of ambient temperature responsive lncRNAs were identified with potential roles in the regulation of temperature-dependent developmental changes, such as the transition from the vegetative to the reproductive (flowering) phase. The challenge for the future is to characterize the biological function and molecular mode of action of the large number of ambient temperature-regulated lncRNAs that have been identified in this study.

Comparison of three modelling approaches for predicting deoxynivalenol contamination in winter wheat
Liu, Cheng ; Manstretta, Valentina ; Rossi, Vittorio ; Fels-Klerx, H.J. van der - \ 2018
Toxins 10 (2018)7. - ISSN 2072-6651
Cereal grains - DON - Food safety - Forecast - Mycotoxin - Validation

Forecasting models for mycotoxins in cereal grains during cultivation are useful for pre-harvest and post-harvest mycotoxin management. Some of such models for deoxynivalenol (DON) in wheat, using two different modelling techniques, have been published. This study aimed to compare and cross-validate three different modelling approaches for predicting DON in winter wheat using data from the Netherlands as a case study. To this end, a published empirical model was updated with a new mixed effect logistic regression method. A mechanistic model for wheat in Italy was adapted to the Dutch situation. A new Bayesian network model was developed to predict DON in wheat. In developing the three models, the same dataset was used, including agronomic and weather data, as well as DON concentrations of individual samples in the Netherlands over the years 2001–2013 (625 records). Similar data from 2015 and 2016 (86 records) were used for external independent validation. The results showed that all three modelling approaches provided good accuracy in predicting DON in wheat in the Netherlands. The empirical model showed the highest accuracy (88%). However, this model is highly location and data-dependent, and can only be run if all of the input data are available. The mechanistic model provided 80% accuracy. This model is easier to implement in new areas given similar mycotoxin-producing fungal populations. The Bayesian network model provided 86% accuracy. Compared with the other two models, this model is easier to implement when input data are incomplete. In future research, the three modelling approaches could be integrated to even better support decision-making in mycotoxin management.

Promoting healthy choices from vending machines : Effectiveness and consumer evaluations of four types of interventions
Bos, Colin ; Lans, Ivo A. van der; Kleef, Ellen van; Trijp, Hans C.M. van - \ 2018
Food Policy (2018). - ISSN 0306-9192
Acceptance - Choice evaluation - Effectiveness - Food choice - Intervention intrusiveness - Vending machine

Vending machines often provide relatively energy-dense snack foods and beverages at a wide variety of points-of-purchase. Vending-machine interventions that stimulate low-calorie choices can therefore play a role in improving the healthfulness of the food environment landscape. The aim of this study is to examine the effects of four vending-machine interventions, varying in level of intrusiveness, on consumers’ choices, consumers’ acceptance of such interventions, and consumers’ evaluations of the choice they made. In a between-subjects design experiment (N = 206), respondents were asked to purchase a snack and a beverage from a vending machine. In addition to a no-intervention condition, four types of incrementally intrusive interventions were implemented: calorie labelling, increasing accessibility of low-calorie choices, increasing prices of high-calorie choices, and restricting availability of high-calorie choices. A post-choice questionnaire included items concerning intervention acceptance, and assortment and choice evaluations. Compared to the no-intervention condition, the most intrusive intervention (i.e. restricting availability of high-calorie choices) led to more low-calorie choices (39% vs. 78%), while less intrusive interventions (i.e. calorie labelling, increasing accessibility of low-calorie choices, and increasing prices of high-calorie choices) did not. Intervention acceptance and choice evaluations were equally high across the four intervention types. Overall, the results suggest that restricting high-calorie options is a promising route to stimulate healthier choices from vending machines. As such, the present study provides intervention opportunities in the combat against obesity for governments and their potential allies, such as food manufacturers and the food service industry.

Mothers' reproductive and medical history misinformation practices as strategies against healthcare providers' domination and humiliation in maternal care decision-making interactions : An ethnographic study in Southern Ghana
Yevoo, Linda L. ; Agyepong, Irene A. ; Gerrits, Trudie ; Dijk, Han van - \ 2018
Care decision-making - Empowerment - Ethnography - Ghana - Power - Pregnant women - Respectful maternal care

Background: Pregnant women can misinform or withhold their reproductive and medical information from providers when they interact with them during care decision-making interactions, although, the information clients reveal or withhold while seeking care plays a critical role in the quality of care provided. This study explored 'how' and 'why' pregnant women in Ghana control their past obstetric and reproductive information as they interact with providers at their first antenatal visit, and how this influences providers' decision-making at the time and in subsequent care encounters. Methods: This research was a case-study of two public hospitals in southern Ghana, using participant observation, conversations, interviews and focus group discussions with antenatal, delivery, and post-natal clients and providers over a 22-month period. The Ghana Health Service Ethical Review Committee gave ethical approval for the study (Ethical approval number: GHS-ERC: 03/01/12). Data analysis was conducted according to grounded theory. Results: Many of the women in this study selectively controlled the reproductive, obstetric and social history information they shared with their provider at their first visit. They believed that telling a complete history might cause providers to verbally abuse them and they would be regarded in a negative light. Examples of the information controlled included concealing the actual number of children or self-induced abortions. The women adopted this behaviour as a resistance strategy to mitigate providers' disrespectful treatment through verbal abuses and questioning women's practices that contradicted providers' biomedical ideologies. Secondly, they utilised this strategy to evade public humiliation because of inadequate privacy in the hospitals. The withheld information affected quality of care decision-making and care provision processes and outcomes, since misinformed providers were unaware of particular women's risk profile. Conclusion: Many mothers in this study withhold or misinform providers about their obstetric, reproductive and social information as a way to avoid receiving disrespectful maternal care and protect their privacy. Improving provider client relationship skills, empowering clients and providing adequate infrastructure to ensure privacy and confidentiality in hospitals, are critical to the provision of respectful maternal care.

Erythrocyte fouling on micro-engineered membranes
Amar, Levy I. ; Guisado, Daniela ; Faria, Monica ; Jones, James P. ; Rijn, Cees J.M. van; Hill, Michael I. ; Leonard, Edward F. - \ 2018
Blood - Cross-flow - Erythrocytes - Fouling - Microfiltration model - Microfluidics - Microsieve - Nanopores - Photolithography - Sieve

Crossflow microfiltration of plasma from blood through microsieves in a microchannel is potentially useful in many biomedical applications, including clinically as a wearable water removal device under development by the authors. We report experiments that correlate filtration rates, transmembrane pressures (TMP) and shear rates during filtration through a microscopically high channel bounded by a low intrinsic resistance photolithographically-produced porous semiconductor membrane. These experiments allowed observation of erythrocyte behavior at the filtering surface and showed how their unique deformability properties dominated filtration resistance. At low filtration rates (corresponding to low TMP), they rolled along the filter surface, but at higher filtration rates (corresponding to higher TMP), they anchored themselves to the filter membrane, forming a self-assembled, incomplete monolayer. The incompleteness of the layer was an essential feature of the monolayer’s ability to support sustainable filtration. Maximum steady-state filtration flux was a function of wall shear rate, as predicted by conventional crossflow filtration theory, but, contrary to theories based on convective diffusion, showed weak dependence of filtration on erythrocyte concentration. Post-filtration scanning electron micrographs revealed significant capture and deformation of erythrocytes in all filter pores in the range 0.25 to 2 μm diameter. We report filtration rates through these filters and describe a largely unrecognized mechanism that allows stable filtration in the presence of substantial cell layers.

Altered neural inhibition responses to food cues after Roux-en-Y Gastric Bypass
Zoon, H.F.A. ; Bruijn, S.E.M. de; Jager, G. ; Smeets, P.A.M. ; Graaf, C. de; Janssen, I.M.C. ; Schijns, W. ; Deden, L. ; Boesveldt, S. - \ 2018
Biological Psychology 137 (2018). - ISSN 0301-0511 - p. 34 - 41.
Bariatric surgery - fMRI - Food preferences - go/no-go - Impulsivity - Inhibitory control - Weight-Loss

Background: Roux-en-Y gastric bypass (RYGB) surgery is a highly effective weight-loss intervention that often reduces preference and intake of high-energy foods. Research into the neural mechanisms behind this shift has mainly focused on reward processing of food cues. However, the ability to successfully control food intake and thereby weight-loss also depends on inhibitory control capacity. We investigated whether RYGB leads to alterations in neural inhibitory control in response to food cues. Methods: A food-specific go/no-go task with pictures of high-energy (desserts) and low-energy foods (vegetables), was used to assess neural inhibition responses before and after RYGB with functional magnetic resonance imaging. Data from 18 morbidly obese patients (15 females; age 41 ± 11 years; BMI 42 ± 4 kg/m2 before; BMI 36 ± 4 kg/m2 after) were analysed. Pre- and post-RYGB BOLD fMRI responses were compared for response inhibition towards high- and low-energy foods. Participants were tested in a satiated state. Results: Response inhibition to high-energy foods was associated with increased activation of the right lateral prefrontal cortex (PFC), right medial PFC, dorsolateral PFC, right middle cingulate cortex and the right inferior frontal operculum (involved in inhibitory control), after compared to before surgery. Response inhibition to low-energy foods elicited diminished post- compared to pre-surgery responses in the left superior temporal pole, right parahippocampal gyrus and right hypothalamus (involved in metabolic control). Conclusion: Neural changes indicate improved response inhibition towards high-energy food cues, altered influence of metabolic control during response inhibition towards low-energy food cues and a more positive attitude to both high-energy and low-energy food after RYGB. Alterations in neural circuits involved in inhibitory control, satiety signalling and reward processing may contribute to effective weight-loss after RYGB.

How to support sharing & finding Open Educational Resources – a conference recap
Post, Marijn ; Harmelen, M.J. van - \ 2018
Wageningen : OpenScience blog Wageningen University & Research
Care-physical activity initiatives in the neighbourhood : Study protocol for mixed-methods research on participation, effective elements, impact, and funding methods
Wagemakers, Annemarie ; Mulderij, Lisanne S. ; Verkooijen, Kirsten T. ; Groenewoud, Stef ; Koelen, Maria A. - \ 2018
BMC Public Health 18 (2018)1. - ISSN 1471-2458
Care - Effective elements - Funding models - Health in all policies - Participation - Physical activity - Socioeconomic status

Background: In the Netherlands, people with a low socioeconomic status (SES) live approximately 6 years less and are less engaged in physical activity (PA) than high SES citizens. This contributes to the persistent health inequalities between low and high SES citizens. Care-PA initiatives are deemed effective for stimulating PA and improving health and participation among peoples with a low SES. In those initiatives, multiple sectors (e.g. sports, health insurers, municipalities) collaborate to connect primary care and PA at neighbourhood level. This study focuses on two Dutch municipalities that aim to invest in Health in All Policies (HiAP) and care-PA initiatives to improve the health of people with low SES. The aim is to gain insight into (1) the short-term (3 months) and long-term (1 year) outcomes of participating in care-PA initiatives for low SES citizens in terms of health, quality of life, and societal participation, (2) the effective elements that contribute to these outcomes, (3) the direct and perceived societal costs and benefits of care-PA initiatives, and (4) alternative ways to fund integrated care, prevention, and care-PA initiatives at neighbourhood level. Methods: The study will be built on a mixed-methods design guided by action research to continuously facilitate participatory processes and practical solutions. To assess outcomes, body measurements and questionnaires will be used as part of a pre-test/post-test design. Focus groups and interviews will be conducted to gain an in-depth understanding of outcomes and action elements. Action elements will be explored by using multiple tools: concept mapping, the logic model, and capacity mapping. Direct and perceived societal costs will be measured by administrative data from healthcare insurers (before-after design) and the effectiveness arena. An alternative funding model will be identified based on literature study, expert meetings, and municipal workshops. Discussion: Initiatives addressing multiple factors at different levels in an integral way are a challenge for evaluation. Multi-methods and tools are required, and data need to be interpreted comprehensively in order to contribute to a contextual insight into what works and why in relation to HiAP and care-PA initiatives.

The Fusarium graminearum Histone Acetyltransferases Are Important for Morphogenesis, DON Biosynthesis, and Pathogenicity
Kong, Xiangjiu ; Diepeningen, A.D. van; Lee, T.A.J. van der; Waalwijk, C. ; Xu, Jingsheng ; Xu, Jin ; Zhang, Hao ; Chen, Wanquan ; Feng, Jie - \ 2018
Frontiers in Microbiology 9 (2018). - ISSN 1664-302X
Post-translational modifications of chromatin structure by histone acetyltransferase (HATs) play a central role in the regulation of gene expression and various biological processes in eukaryotes. Although HAT genes have been studied in many fungi, few of them have been functionally characterized. In this study, we identified and characterized four putative HATs (FgGCN5, FgRTT109, FgSAS2, FgSAS3) in the plant pathogenic ascomycete Fusarium graminearum, the causal agent of Fusarium head blight of wheat and barley. We replaced the genes and all mutant strains showed reduced growth of F. graminearum. The ΔFgSAS3 and ΔFgGCN5 mutant increased sensitivity to oxidative and osmotic stresses. Additionally, ΔFgSAS3 showed reduced conidia sporulation and perithecium formation. Mutant ΔFgGCN5 was unable to generate any conidia and lost its ability to form perithecia. Our data showed also that FgSAS3 and FgGCN5 are pathogenicity factors required for infecting wheat heads as well as tomato fruits. Importantly, almost no Deoxynivalenol (DON) was produced either in ΔFgSAS3 or ΔFgGCN5 mutants, which was consistent with a significant downregulation of TRI genes expression. Furthermore, we discovered for the first time that FgSAS3 is indispensable for the acetylation of histone site H3K4, while FgGCN5 is essential for the acetylation of H3K9, H3K18, and H3K27. H3K14 can be completely acetylated when FgSAS3 and FgGCN5 were both present. The RNA-seq analyses of the two mutant strains provide insight into their functions in development and metabolism. Results from this study clarify the functional divergence of HATs in F. graminearum, and may provide novel targeted strategies to control secondary metabolite expression and infections of F. graminearum.
Dynamics of post-harvest pathogens Neofabraea spp. and Cadophora spp. in plant residues in Dutch apple and pear orchards
Köhl, J. ; Wenneker, M. ; Haas, B.H. de; Anbergen, R.H.N. ; Goossen-van de Geijn, H.M. ; Pinto, F.A.M.F. ; Kastelein, P. - \ 2018
Plant Pathology 67 (2018)6. - ISSN 0032-0862 - p. 1264 - 1277.
Post-harvest diseases of apple and pear cause significant losses.
Neofabraea spp. and Cadophora spp. infect fruits during the growing season and remain quiescent until disease symptoms occur after several months in storage. Epidemiological knowledge of these diseases is limited. TaqMan PCR assays were developed for quantification of N. alba, N. perennans, C. malorum and C. luteo-olivacea in environmental samples. Various host tissues, dead weeds and grasses, soil and applied composts were collected in 10 apple and 10 pear orchards in May 2012. Neofabraea alba was detected in 73% of samples from apple orchards and 48% from pear orchards. Neofabraea perennans was present in a few samples. Cado- phora luteo-olivacea was detected in 99% of samples from apple orchards and 93% from pear orchards, whilst C. malo-rum was not detected in any sample. In apple orchards, highest concentrations of N. alba
were found in apple leaf litter, cankers and mummies, and of C. luteo-olivacea in apple leaf litter, mummies and dead weeds. In pear orchards, N. alba and C. luteo-olivacea were found in highest concentrations in pear leaf litter and in dead weeds. Substrate colonization varied considerably between orchards. The temporal dynamics of pathogens was followed in four apple orchards and four
pear orchards. In apple orchards the colonization by pathogens decreased from April until August and increased from September until December. This pattern was less pronounced in pear. Knowledge on population dynamics is essential for
the development of preventative measures to reduce risks of fruit infections during the growing season.
The effects of an online learning environment with worked examples and peer feedback on students’ argumentative essay writing and domain-specific knowledge acquisition in the field of biotechnology
Valero Haro, Anahuac ; Noroozi, Omid ; Biemans, Harm J.A. ; Mulder, Martin - \ 2018
Journal of Biological Education (2018). - ISSN 0021-9266 - 9 p.
biotechnology - Essay writing - example-based learning - online learning environment - peer feedback

The present study investigated the effects of an online learning environment supported with worked examples and peer feedback on students’ argumentative essay writing and domain-specific knowledge acquisition in the field of biotechnology. As part of a bigger project, a pre- and post-test study design was used with 45 bachelor students who were randomly grouped in pairs. Students were asked to analyse a case and write an argumentative essay taking into account the advantages and disadvantages of genetically modified organisms. The results showed that the combination of worked examples and peer feedback improve the quality of argumentative essay writing and facilitate the acquisition of domain-specific knowledge. Implications, suggestions, and future research are discussed.

Divergent hydraulic strategies to cope with freezing in co-occurring temperate tree species with special reference to root and stem pressure generation
Yin, Xiao Han ; Sterck, Frank ; Hao, Guang You - \ 2018
New Phytologist 219 (2018)2. - ISSN 0028-646X - p. 530 - 541.
cavitation - freeze–thaw cycle - frost fatigue - root pressure - temperate forest - xylem hydraulics

Some temperate tree species mitigate the negative impacts of frost-induced xylem cavitation by restoring impaired hydraulic function via positive pressures, and may therefore be more resistant to frost fatigue (the phenomenon that post-freezing xylem becomes more susceptible to hydraulic dysfunction) than nonpressure-generating species. We test this hypothesis and investigate underlying anatomical/physiological mechanisms. Using a common garden experiment, we studied key hydraulic traits and detailed xylem anatomical characteristics of 18 sympatric tree species. These species belong to three functional groups, that is, one generating both root and stem pressures (RSP), one generating only root pressure (RP), and one unable to generate such pressures (NP). The three functional groups diverged substantially in hydraulic efficiency, resistance to drought-induced cavitation, and frost fatigue resistance. Most notably, RSP and RP were more resistant to frost fatigue than NP, but this was at the cost of reduced hydraulic conductivity for RSP and reduced resistance to drought-induced cavitation for RP. Our results show that, in environments with strong frost stress: these groups diverge in hydraulic functioning following multiple trade-offs between hydraulic efficiency, resistance to drought and resistance to frost fatigue; and how differences in anatomical characteristics drive such divergence across species.

EU agricultural policy : Interpretive approaches to the EU
Feindt, P.H. - \ 2018
In: Handbook of European Policies / Heinelt, Hubert, Münch, Sybille, Edward Elgar - ISBN 9781784719357 - p. 115 - 133.
This contribution takes a discourse analytical perspective to discuss long-term change and ideational power in the EU’s Common Agricultural Policy (CAP). Initially the CAP replaced national farm support policies, absorbing productivist discourses that treated agriculture as exceptional. Productivism legitimised the CAP as farm income policy and achieved ideational hegemony. From 1980, a neoliberal discourse questioned farmers’ special treatment, focusing on efficiency, performance and effective use of taxpayer money. In response, the emerging multifunctionality discourse emphasised agriculture’s complex functions for rural areas and ecosystems, rallying to spend ‘public money for public goods’. Since the late 1990s, the three discourses have shared persuasive power in ideas. Consequently the Commission adopted a hybrid discourse, which allows member states to strategically select suitable elements for domestic persuasion. While the CAP has become chronically contested in policy fora, policy developments indicate that in decisive policy arenas, agricultural productivism and (post-) exceptionalism are still dominant and deeply entrenched.
Past, present & future of information technology in pedometrics
Rossiter, David - \ 2018
Geoderma 324 (2018). - ISSN 0016-7061 - p. 131 - 137.
Although pedometric approaches were taken as early as 1925, the post-WWII development of information technology radically transformed the possibilities for applying mathematical methods to soil science. The most significant development is the digital computer and associated developments in computer science. These allowed statistical inference on large pedometric datasets, e.g., numerical taxonomy of soils from the early 1960s and geostatistics from the mid-1970s, as well as simulation models of soil processes. By the time of the first Pedometrics conference in 1992 sufficient computing power was available for stochastic simulation and complex geostatistical procedures such as disjunctive kriging. In the intervening 25 years computing power has grown to almost magical proportions, allowing individual scientists to carry out complex procedures. A second development is the growth of networking. This facilitates collaboration among pedometricians, rapid communication with journals, collaborative programming and publication, and easy access to resources. A third development is the availability of on-line storage of large datasets, especially of open data, including GIS coverages and remotely-sensed images. This allows pedometricians working on geographic problems to integrate sources from multiple disciplines, most notably in digital soil mapping using a wide variety of covariates related to soil genesis. It also promotes the an open-source movement of collaborative development of computer programs useful for pedometrics. A fourth development is the wide range of digital sensors which provide data for pedometrics; sensors include spectroscopy, electromagnetic induction, and γ-ray detectors., connected to each other and to central data stores. A fifth development is wireless technology, including mobile computing and telephony, again greatly facilitating rapid and extensive data collection – in pedometrics, the more dense the data, the greater the analytical possibilities and the lower the uncertainty. A final development is a global navigation satellite system (e.g., GPS), making accurate georeference of field data a routine part of data collection, and thereby assuring the highest possible accuracy in maps made by predictive pedometric methods. As computer power increases, models can be correspondingly detailed. As sensor networks and remote sensing provide ever more abundant and spatiotemporally fine-resolution measurements, the challenge is to manage this information and maintain the link with pedologic and soil-landscape knowledge, within the context of societal needs for the results of pedometric analysis.
Population complexity trumps model complexity in understanding trait variation
Sterken, M.G. ; Snoek, L.B. ; Bevers, R.P.J. ; Volkers, J.M. ; Riksen, J.A.G. ; Kammenga, J.E. - \ 2018
The study of expression quantitative trait loci (eQTL) through the use of recombinant inbred lines has yielded detailed information about the transcriptional regulation of complex traits. However, it has proven difficult to apply more advanced genetic models explaining genetic variation underlying gene expression differences. Here, we make use of the difference in genetic complexity of two types of inbred population in the nematode Caenorhabditis elegans to estimate the number of loci affecting gene expression.
We measured gene-expression in a recombinant inbred line (RIL) and an introgression line (IL) population constructed from crossing the strains N2 and CB4856. Both populations received a heat-shock treatment and gene-expression profiles were obtained before (48h at 20oC), directly after heat-shock (2h at 35oC), and after a recovery period (2h at 20oC). Making use of the difference in genetic make-up between the populations - few loci from one parent in the IL versus many in the RILs - allowed for the identification of transcripts regulated by multiple loci. By measuring the transcript variance within each population, for over 1,000 genes across the three conditions we found strong evidence for multiple eQTL underlying gene expression variation. Importantly, most of these multi-loci eQTL are environment-specific. Furthermore, we observed over 200 genes where the phenotypic variation in the IL panel significantly exceeded that in the RIL panel, suggesting evidence for complex genetic buffering.
In conclusion, by using two types of inbred populations the complexity of trait architectures can be investigated without reliance on models of higher complexity. The genetic complexity of a trait is directly observed, rather than estimated post-hoc. Therefore, relying on population complexity rather than model complexity can provide valuable insight in the architecture of quantitative traits.
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