Photosynthetic properties of two symbiotic demosponges were compared using Clark-type oxygen microsensors. The putatively distinct sponge species, Cliona viridis (Schmidt, 1862) and Cliona nigricans (Schmidt, 1862) were discriminated by their mean megasclere lengths of 296 and 387 lm, respectively. Photosynthetic behavior was used to generate additional taxonomic information. Sponge-dinoflagellate symbioses were well adapted to low light due to the hosts' endolithic lifestyle. Both sponges reached light compensation and saturation at similar light levels with means close to 10 and 30 lmol photons . m À 2 . s À 1 , respectively. The gross photosynthetic activity was closely related to symbiont cell density in the sponge surface tissue. Mean symbiont densities, chl a content, and gross photosynthesis were about six times higher in C. viridis than in C. nigricans, with respective values of 3000 and 440 symbiont . mm À 2 , 1.3 and 0.2 lg chl a . g À 1 , and 5.4 and 1.0 lmol O 2 . cm À 3 . s À 1 gross photosynthesis. Net photosynthesis and respiration could not be calculated accurately from the oxygen gradients, because significant gas exchange occurs through the pumping activity. Thus, assumptions of diffusional oxygen exchange via the surface do not hold for sponges. Combined data of this study indicate that the metabolic activity of C. viridis depends on photosynthetic activity of its symbionts, whereas C. nigricans appears to have a higher pumping intensity and is more actively filter feeding. The difference in photosynthetic activities is not caused by different light adaptations but provides new evidence against the conspecifity of C. viridis and C. nigricans.

The introduction of serious games as pedagogical supports in the field of education is a process gaining in popularity amongst the teaching community. This article creates a link between the integration of new pedagogical solutions in first-year primary class and the fundamental research on the motivation of the players/learners, detailing an experiment based on a game specifically developed, named QCM. QCM considers the learning worksheets issued from the Freinet pedagogy using various gameplay mechanisms. The main contribution of QCM in relation to more traditional games is the dissociation of immersion mechanisms, in order to improve the understanding of the user experience. This game also contains a system of gameplay metrics, the analysis of which shows a relative increase in the motivation of students using QCM instead of paper worksheets, while revealing large differences in students behavior in conjunction with the mechanisms of gamification employed.

L'introduction des jeux-vid éo s érieux comme soutiens p édagogiques dans le domaine de l'enseignement est un processus de plus en plus d émocratis é. En parall èle de cette introduction, la recherche en "game studies" repr ésente une discipline acad émique tr ès active qui s'int éresse à l'analyse des syst èmes vid éoludiques complexes, notamment en ce qui concerne la compr éhension de l'exp érience des joueurs, et les m écanismes principaux d'immersion. Cet article cr é é un lien entre l'utilisation en Cours Pr éparatoire de nouvelles solutions ludo-p édagogiques, et la recherche capitale sur la motivation des joueurs/apprenants, en d étaillant une exp érience bas ée sur un jeu d évelopp é sp écifiquement (nomm é QCM), ludifiant par diff érents m écanismes d'immersion des fichiers d'apprentissage issus de la p édagogie Freinet. L'apport principal pour la recherche de QCM par rapport à des jeux-s érieux plus traditionnels r éside dans la dissociation des m écanismes d'immersion afin d'am éliorer la compr éhension de l'exp érience des utilisateurs. Ce jeu contient également un syst ème de m étriques d'utilisation, dont l'analyse indique une relative hausse de la motivation des él èves utilisant QCM au lieu des fiches papiers, mais r év èle surtout des grandes diff érences de comportement selon les él èves et les m écanismes de ludification employ és.

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Hussein et al., 303Association of IL4 gene polymorphism with severity of asthma among Egyptian patients