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291.
We define electronic platforms as two-sided markets in which two groups of agents – sellers and buyers – can switch from one side of the market to the other. Using a duopoly model, we interpret equilibrium fees and profits in terms of rewards and penalties, relative to the equilibrium without side-switching. We establish that if the group with the highest side-switching probability has the lowest externality parameter, platforms make more profit with side-switching. It is also shown that agents' heterogeneity is favorable to platform profitability.  相似文献   
292.
The self‐teaching hypothesis suggests that knowledge about the orthographic structure of words is acquired incidentally during reading through phonological recoding. The current study assessed whether visual processing skills during reading further contribute to orthographic learning. French children were asked to read pseudowords. The whole pseudoword letter string was available at once for half of the targets while the pseudoword's sub‐lexical units were discovered in turn for the other half. Then memorisation of the targets’ orthographic form was assessed. Although most pseudowords were accurately decoded, target orthographic forms were recognised more often when the pseudowords entire orthographic sequence was available at once during the learning phase. The whole‐word presentation effect was significant and stable from third to fifth grades. This effect was affected neither by target reading accuracy nor by target reading speed during the learning phase. Results suggest that beyond recoding skills, the ability to process the entire orthographic letter string at once during reading contributes to efficient orthographic learning.  相似文献   
293.
The combined influence of maturation, ripening, and climate on the profile of bioactive compounds was studied in banana (Musa acuminata, AAA, Cavendish, cv. Grande Naine). Their bioactive compounds were determined by the Folin-Ciocalteu assay and high-performance thin layer chromatographic (HPTLC) method. The polyphenol content of bananas harvested after 400 degree days remained unchanged during ripening, while bananas harvested after 600 and 900 degree days exhibited a significant polyphenol increase. Although dopamine was the polyphenol with the highest concentration in banana peels during the green developmental stage and ripening, its kinetics differed from the total polyphenol profile. Our results showed that this matrix of choice (maturation, ripening, and climate) may allow selection of the banana (M. acuminata, AAA, Cavendish, cv. Grande Naine) status that will produce optimal concentrations of identified compounds with human health relevance.  相似文献   
294.
Abstract

In West Africa, advisory services for family farms have been promoted to better address producers’ needs. The paper aims to show that these services can be understood as a system whose functioning is strongly determined by the financing mechanisms, the governance mechanisms put in place, the quality of human resources delivering advice, and the characteristics of the advisory method. The study is based on an analysis of two case studies in Benin and Burkina Faso using a common framework derived from an agricultural advisory system approach. The study highlights the strong interaction between the different components of the system. It shows that (i) the intervention method needs to be continuously adapted to take into account changes in financial capabilities and human resources available for providing advisory services, (ii) the nature and the quality of advisory activities are closely related to the skills of advisors and managers of advisory services, (iii) the governance mechanisms steering advisory services reveal the social relations between the stakeholders and influence the content of the advice, and (iv) the funding mechanisms are pivotal in defining the rules of governance. Lessons learned are drawn from this analysis that may serve to support advisory services.  相似文献   
295.
Abstract

The aim of the present study was to examine, in highly trained young soccer players, the mechanical horizontal determinants of acceleration (Acc) and maximal sprinting speed (MSS). Eighty-six players (14.1 ± 2.4 year) performed a 40-m sprint to assess Acc and MSS. Speed was measured with a 100-Hz radar, and theoretical maximal velocity (V0), horizontal force (F0) and horizontal power (Pmax) were calculated. Within each age group, players were classified as high Acc/fast MSS (>2% faster than group mean), medium (between ?2% and +2%), and low/slow (>2% slower). Acc and MSS were very largely correlated (?0.79; 90% confidence limit [?0.85; ?0.71]). The determinants (multiple regression r2 = 0.84 [0.78; 0.89]) of Acc were V0 (partial r: 0.80 [0.72; 0.86]) and F0 (0.57 [0.44; 0.68]); those of MSS (r2 = 0.96 [0.94; 0.97]) were V0 (0.96 [0.94; 0.97]) and Pmax (0.73 [0.63; ?0.80]). High/Med have likely greater F0 (Cohen’s d: +0.8 [0.0; 1.5]), V0 (+0.6 [?0.1; 1.3]) and Pmax (+0.9 [0.2; 1.7]) than Low/Med. High/Fast have an almost certainly faster V0 (+2.1 [1.5; 2.7]) and a likely greater Pmax (+0.6 [?0.1; 1.3]) than High/Med, with no clear differences in F0 (?0.0 [?0.7; 0.6]). Speed may be a generic quality, but the mechanical horizontal determinants of Acc and MSS differ. While maximal speed training may improve both Acc and MSS, improving horizontal force production capability may be efficient to enhance sprinting performance over short distances.  相似文献   
296.
We investigated whether children who were learning to read simultaneously in English and French activate phonological representations from only the language in which they are reading or from both of their languages. Children in French Immersion programs in Grade 3 were asked to name aloud cognates, interlingual homographs, interlingual homophones, and matched control words. Half of the participants performed the task in English, their first oral language, and half performed the task in French. Control monolingual children in each language were also tested. In the French reading task, fewer errors were observed for cognates and interlingual homophones than for matched control words, whereas more errors were produced for interlingual homographs than matched controls. Only the inhibitory interlingual homograph effect was observed in the English reading task. These data provide evidence that phonological activation in bilinguals is not language selective. The locus of each of these effects in the bilingual word recognition system is discussed.  相似文献   
297.
Safeguarding and exploiting Cultural Heritage induce the production of numerous and heterogeneous data. The management of these data is an essential task for the use and the diffusion of the information gathered on the field. Previously, the data handling was a hand-made task done thanks to efficient and experienced methods. Until the growth of computer science, other methods have been carried out for the digital preservation and treatment of Cultural Heritage information. The development of computerized data management systems to store and make use of archaeological datasets is then a significant task nowadays. Especially for sites that have been excavated and worked without computerized means, it is now necessary to put all the data produced onto computer. This allows preservation of the information digitally (in addition with the paper documents) and offers new exploitation possibilities, like the immediate connection of different kinds of data for analyses, or the digital documentation of the site for its improvement. Geographical Information Systems have proved their potentialities in this scope, but they are not always adapted to the management of features at the scale of a particular archaeological site. Therefore this paper aims to present the development of a Virtual Research Environment dedicated to the exploitation of intra-site Cultural Heritage data. The Information System produced is based on open-source software modules dedicated to the Internet, so users can avoid being software driven and can register and consult data from different computers. The system gives the opportunity to do exploratory analyses of the data, especially at spatial and temporal levels. The system is compliant to every kind of Cultural Heritage site and allows management of diverse types of data. Some experimentation has been done on sites managed by the Service of the National Sites and Monuments of Luxembourg.  相似文献   
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300.
This study assessed the influence of individual and contextual factors on adolescent girls’ interest in school physical education (PE). Specifically, girls (N = 700) were assessed on: (a), perceptions of their PE class climate, using the Perceived Motivational Climate Scale (PMCS, Cury et al., 1994; (b) dispositional achievement goal orientations, using the French version of the Perception of Success Questionnaire (POSQ, Durand et alM in press; and (c) the interest and competence subscales from the French version of the Intrinsic Motivation Inventory (IMI, Cury et al., 1994a). Structural equation modelling analysis, using LISREL VII, showed an excellent fit with the hypothesised model. Specifically, situational class climate was found to be more important than individual goals in influencing pupil interest in PE. However, perceived competence also influenced interest, as did a mastery goal orientation. Results are discussed in the context of theoretical propositions of goal perspectives theory and practical issues of enhancing adolescent girls’ interest in physical education.  相似文献   
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