Information Problem Solving: Analysis of a Complex Cognitive Skill

In (higher) education students are often faced with information problems: tasks or assignments which require the student to identify information needs, locate corresponding information sources, extract and organize relevant information from each source, and synthesize information from a variety of sources. It is often assumed that students master this complex cognitive skill all by themselves. In our point of view, however, explicit and intensive education is required. In order to design education that fosters the information problem solving skill, a skill decomposition is required. In this research the complex cognitive skill of information problem solving is analysed. Experts and novices were observed while solving an information problem. Preliminary results reveal that experts spend more time on the sub-skills 'defining the problem', 'processing the information' and 'presenting the information'. They also regulate their process more oftenIn: A.J. Kallenberg and M.J.J.M. van de Ven (Eds), 2002, The New Educational Benefits of ICT in Higher Education: Proceedings. Rotterdam: Erasmus Plus BV, OECR ISBN 90-9016127-

Le phosphore limite-t-il la production intensive du riz dans la plaine de Bagré au Burkina Faso ?

Le phosphore (P) est un élément important dans la nutrition minérale du riz et dans l’élaboration du rendement paddy. Des essais soustractifs ont été conduits en milieu paysan dans la plaine rizicole de Bagré au cours de trois campagnes successives pour évaluer l’effet de l’application de P sur le rendement paddy. La capacité nutritive du sol en phosphore a varié entre 7 et 15 kg P ha-1. L’application de P a augmenté l’efficacité physiologique interne de P qui a varié entre 211 et 290 kg paddy kg-1 P (moyenne 249 kg kg-1). L’efficacité agronomique de P a été de 33,7 kg paddy kg–1 de P appliqué. L’augmentation de rendement due à l’application de phosphore a été de 19%. En moyenne, 70% du phosphore total absorbé est contenu dans les grains. L’évolution du rendement paddy indique que P est le second facteur limitant dans la plaine de Bagré après l’azote. L’application de P_engrais à une dose moyenne de 30 kg P ha-1 était suffisante pour compenser les pertes dues aux exportations. Le phosphore limite la production de riz à Bagré mais son application comme engrais contribue à améliorer les rendements paddy et à compenser les pertes de P du système.Mots clés : Capacité nutritive des sols, rizières, efficacité d’utilisation de nutriments, bilan minéral

Effects of organically and conventionally produced feed on biomarkers of health in a chicken model

Consumers expect organic products to be healthier. However, limited research has been performed to study the effect of organic food on health. The present study aimed to identify biomarkers of health to enable future studies in human subjects. A feeding experiment was performed in two generations of three groups of chickens differing in immune responsiveness, which were fed identically composed feeds from either organic or conventional produce. The animals of the second generation were exposed to an immune challenge and sacrificed at 13 weeks of age. Feed and ingredients were analysed on macro- and micronutrients, i.e. vitamins, minerals, trace elements, heavy metals and microbes. The chickens were studied by general health and immune parameters, metabolomics, genomics and post-mortem evaluation. The organic and conventional feeds were comparable with respect to metabolisable energy. On average, the conventionally produced feeds had a 10 % higher protein content and some differences in micronutrients were observed. Although animals on both feeds were healthy, differences between the groups were found. The random control group of chickens fed conventional feed showed overall a higher weight gain during life span than the group on organic feed, although feed intake was mostly comparable. The animals on organic feed showed an enhanced immune reactivity, a stronger reaction to the immune challenge as well as a slightly stronger ‘catch-up growth’ after the challenge. Biomarkers for future research were identified in the parameters feed intake, body weight and growth rate, and in immunological, physiological and metabolic parameters, several of these differing most pronounced after the challeng

Tuning dissipation dilution in 2D material resonators by MEMS-induced tension

Resonators based on two-dimensional (2D) materials have exceptional properties for application as nanomechanical sensors, which allows them to operate at high frequencies with high sensitivity. However, their performance as nanomechanical sensors is currently limited by their low quality ($Q$)-factor. Here, we make use of micro-electromechanical systems (MEMS) to apply pure in-plane mechanical strain, enhancing both their resonance frequency and Q-factor. In contrast to earlier work, the 2D material resonators are fabricated on the MEMS actuators without any wet processing steps, using a dry-transfer method. A platinum clamp, that is deposited by electron beam-induced deposition, is shown to be effective in fixing the 2D membrane to the MEMS and preventing slippage. By in-plane straining the membranes in a purely mechanical fashion, we increase the tensile energy, thereby diluting dissipation. This way, we show how dissipation dilution can increase the $Q$-factor of 2D material resonators by 91\%. The presented MEMS actuated dissipation dilution method does not only pave the way towards higher $Q$-factors in resonators based on 2D materials, but also provides a route toward studies of the intrinsic loss mechanisms of 2D materials in the monolayer limit.Comment: 20 pages, 15 figure

Nodule Organogenesis and Symbiotic Mutants of the Model Legume \u3ci\u3eLotus japonicus\u3c/i\u3e

A detailed microscopical analysis of the morphological features that distinguish different developmental stages of nodule organogenesis in wild-type Lotus japonicus ecotype Gifu B-129-S9 plants was performed, to provide the necessary framework for the evaluation of altered phenotypes of L. japonicus symbiotic mutants. Subsequently, chemical ethyl methanesulfonate (EMS) mutagenesis of L. japonicus was carried out. The analysis of approximately 3,000 M1 plants and their progeny yielded 20 stable L. japonicus symbiotic variants, consisting of at least 14 different symbiosis- associated loci or complementation groups. Moreover, a mutation affecting L. japonicus root development was identified that also conferred a hypernodulation response when a line carrying the corresponding allele (LjEMS102) was inoculated with rhizobia. The phenotype of the LjEMS102 line was characterized by the presence of nodule structures covering almost the entire root length (Nod++), and by a concomitant inhibition of both root and stem growth. A mutation in a single nuclear gene was shown to be responsible for both root and symbiotic phenotypes observed in the L. japonicus LjEMS102 line, suggesting that (a) common mechanism(s) regulating root development and nodule formation exists in legumes

Yield gaps, nutrient use efficiencies and response to fertilisers by maize across heterogeneous smallholder farms of western Kenya

The need to promote fertiliser use by African smallholder farmers to counteract the current decline in per capita food production is widely recognised. But soil heterogeneity results in variable responses of crops to fertilisers within single farms. We used existing databases on maize production under farmer (F-M) and researcher management (R-M) to analyse the effect of soil heterogeneity on the different components of nutrient use efficiency by maize growing on smallholder farms in western Kenya: nutrient availability, capture and conversion efficiencies and crop biomass partitioning. Subsequently, we used the simple model QUEFTS to calculate nutrient recovery efficiencies from the R-M plots and to calculate attainable yields with and without fertilisers based on measured soil properties across heterogeneous farms. The yield gap of maize between F-M and R-M varied from 0.5 to 3 t grain ha-1 season-1 across field types and localities. Poor fields under R-M yielded better than F-M, even without fertilisers. Such differences, of up to 1.1 t ha-1 greater yields under R-M conditions are attributable to improved agronomic management and germplasm. The relative response of maize to N-P-K fertilisers tended to decrease with increasing soil quality (soil C and extractable P), from a maximum of 4.4-fold to -0.5- fold relative to the control. Soil heterogeneity affected resource use efficiencies mainly through effects on the efficiency of resource capture. Apparent recovery efficiencies varied between 0 and 70% for N, 0 and 15% for P, and 0 to 52% for K. Resource conversion efficiencies were less variable across fields and localities, with average values of 97 kg DM kg-1 N, 558 kg DM kg-1 P and 111 kg DM kg-1 K taken up. Using measured soil chemical properties QUEFTS over-estimated observed yields under F-M, indicating that variable crop performance within and across farms cannot be ascribed solely to soil nutrient availability. For the R-M plots QUEFTS predicted positive crop responses to application of 30 kg P ha-1 and 30 kg P ha-1 + 90 kg N ha-1 for a wide range of soil qualities, indicating that there is room to improve current crop productivity through fertiliser use. To ensure their efficient use in sub-Saharan Africa mineral fertilisers should be: (1) targeted to specific niches of soil fertility within heterogeneous farms; and (2) go hand-in-hand with the implementation of agronomic measures to improve their capture and utilisation

The dynamics of Africa’s fruit and vegetable processing sectors

The production of fruits and vegetables (F&V) in Africa has increased 3.3 percent annually during the last 20 years, but only 0.7 percent in per capita terms (FAOSTAT 2022; Figure 3.1). Africa has the lowest per capita production and consumption of F&V in the world, although South Africa, Morocco, and Egypt are large producers and exporters

How to find and diagnose a CDG due to defective N-glycosylation

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