The State-of-the-Art of Collaborative Technologies for Initial Vocational Education: A Systematic Literature Review

Future workplaces require collaboration skills in which members of different work communities use technologies to solve complex problems. Vocational education and training (VET) programs need to meet the challenge to prepare students to be part of a competent workforce. Particularly initial vocational education is under pressure to develop learners’ collaboration skills and abilities. To date, however, no attempt has been made to perform a comprehensive review of the use of computer-supported collaborative learning (CSCL) technologies across different vocational education settings to account for contextual factors of VET. In this systematic review, 26 published studies were analyzed with respect to their demographics, research methodology, use of technology, and measured outcomes. This review illuminates that research on CSCL still leaves the vocational learning context as an under-represented field of study. At the same time, technologies offer a range of new types of learning possibilities for vocational education. As the direct result of that development, vocational education is increasingly taking place in new technology-enhanced learning settings. Education can benefit from the opportunities of CSCL technologies, but on the other hand, such technologies create new challenges for facilitating vocational learning. Therefore, this review also identifies three topic areas specific to vocational learning (collaborative writing-to-learn, simulations and game-like solutions, and tangible objects) and enumerates desirable lines for future research

Evolution of carbonated lacustrine environment with stromatolites : a paleoecological approach (quarry of Montaigu-le-Blin, Limagne graben, Allier, France)

La carrière de Montaigu-le-Blin, située en Limagne bourbonnaise permet d’analyser en détail la sédimentation lacustre aquitanienne et de reconstituer les environnements de dépôt. Les sédiments marneux et calcaires renferment une faune d’eau douce et une flore particulièrement développées. Les dépôts sédimentaires traduisent des variations périodiques du niveau de la tranche d’eau qui provoquent aussi des variations périodiques des conditions chimiques au sein du lac. Ils sont représentatifs de milieux alternativement anoxiques et oxygénés. Ces variations sont le résultat d’alternances de périodes d’humidité variable, et seraient donc d’origine climatique. Ces alternances ont provoqué des variations périodiques des assemblages floro-fauniques : des thanatocœnoses surviennent durant les périodes anoxiques, alors que le développement majeur des algues encroûtantes responsables de la formation de concrétions algaires, apparaît lors des périodes oxygénées. Ces périodes sont également marquées par une augmentation de l’hydrodynamisme, associée à des apports détritiques du bassin versant. Les stromatolithes présents dans le milieu montrent des morphologies très variées, tributaires des associations de flore et de faune (algues, bactéries, fourreaux de larves de Trichoptères) qui les composent, ainsi que de leur milieu de croissance. Les associations de stromatolithes forment des complexes plurimétriques que l’on propose de situer par rapport à un paléorivage

Niche complementarity and facilitation drive positive diversity effects on biomass production in experimental benthic diatom biofilms

Up to now, relatively few diversity-production experiments have been performed using microorganisms. Benthic diatom communities from estuarine intertidal mudflats are especially interesting for this purpose as they are relatively species poor and are thus more easy to simulate in laboratory conditions. We studied the effect of diversity on biomass production during microcosm experiments with diatoms assembled in combinations of up to eight species. Our results demonstrate a highly positive effect of biodiversity on production, with transgressive overyielding occurring in more than half of the combinations. These strong positive diversity effects could largely be attributed to positive complementarity effects (covering both niche complementarity and facilitation), although negative selection effects effects at higher diversities. We found a significant positive relation between functional diversity and the net biodiversity effects, indicating niche complementarity. In addition, we provide one of the first mechanistic evidences for facilitation by which biodiversity can enhance ecosystem functioning. This was demonstrated by the improved growth of Cylindrotheca closterium after addition of spent medium obtained from other diatom species. The stimulated growth of C. closterium was explained by a shift to mixotrophic growth with a down-regulation of the photosynthetic apparatus

Geoheritage, a National Inventory in France

International audienceGood protection measures for geological heritage should begin with an inventory of geosites. In France, for example, a law enacted in 2002 grants formal recognition to the notion of geological heritage. An inventory and evaluation were then established on a region-by-region basis. By April 2007, the French Ministry of Environment launched the inventory programme for the nation’s geological heritage and the data are now being collected at a regional scale. The data are being gathered and homogenised, and then transferred to the French National Museum of Natural History for examination.The ratified site data are stored and available for public use on a website (http://inpn.mnhn.fr) in a similar structure to natural data that are also processed and stored (flora, fauna, ecosystems, habitats). Today, protecting global heritage is understood as a dynamic process. Instead of placing objects beneath a display case, the conservation approach is now a more modern, active effort, which facilitates access for knowledge and researc

Tectonic history of the northern Peru convergent margin during the past 400 ka

The late Pleistocene tectonic history of the northern Peru convergent margin can be retraced using data collected during deep-sea dives of the submersible Nautile combined with a recent Hydrosweep survey conducted off Peru at lat 5°-6°S by the R/V Sonne. During the past 400 ka, a broad rollover fold formed in the middle slope area, in association with a major seaward-dipping detachment fault. A catastrophic debris avalanche occurred as the result of oversteepening of the landward flank of the rollover fold. The gravity failure of the slope, previously recognized by SeaBeam mapping, occurred at 13.8 ±2.7 ka and produced a destructive tsunami

A new scenario for the Domerian-Toarcian transition

Pour tenter de mieux comprendre l’événement d’anoxie océanique globale au Toarcien inférieur, il convient de remonter aux changements environnementaux qui ont précédé cette phase paroxysmale. En effet, la comparaison des séquences sédimentaires et biostratigraphiques du passage Domérien-Toarcien entre la Téthys occidentale (Maroc, Espagne, Portugal) et l’Europe du Nord-Ouest (Causses, Allemagne, Angleterre) fait apparaître une importante lacune dans la région septentrionale. La faune d’Arieticeratinae (Emaciaticeras, Canavaria, Fontanelliceras) et d’Harpoceratinae (Lioceratoides, Neolioceratoides), accompagnée ensuite de Dactylioceras particuliers (groupe mirabile-polymorphum = sous-genre Eodactylites), fait presque totalement défaut en Europe du Nord-Ouest, alors qu’elle abonde dans les dernières alternances marno-calcaires, sans changement lithologique notable avec le Domérien des coupes téthysiennes. Cette faune est intercalée entre les derniers Pleuroceras et les Dactylioceras du groupe tenuicostatum. Ces derniers apparaissent dans les argiles succédant immédiatement au dernier banc calcaire à Dactylioceras mirabile au Portugal notamment. C’est là le diachronisme déjà reconnu entre les limites lithostratigraphique (disparition des bancs calcaires) et biostratigraphique (apparition du genre Dactylioceras) au passage Domérien-Toarcien. Cette observation peut s’intégrer dans un nouveau scénario paléo-océanographique prenant en compte à la fois la tendance régressive majeure du Domérien supérieur (conduisant à une lacune régionale importante), l’abondance de matière charbonneuse dans les premiers dépôts transgressifs du Toarcien et l’événement anoxique global subséquent. Dans la partie supérieure du Domérien, l’existence d’un fort volcanisme peut être déduite des données relatives aux variations des isotopes du strontium [McArthur et al., 2000]. A ce pic de strontium sont associées une faible anomalie négative du δ13 C à la limite Domérien-Toarcien et des valeurs particulièrement élevées du δ18 O [Morettini et Bartolini, 1999]. Nous pensons que cette activité volcanique débute par des émissions massives de SO2 induisant des pluies acides, un obscurcissement et un refroidissement. A cette phase de refroidissement correspond une augmentation de l’englacement des pôles et une régression responsable de la lacune majeure évoquée plus haut, particulièrement sensible dans les mers épicontinentales. Bien que les preuves directes d’une glaciation fini-domérienne fassent actuellement défaut [Hallam, 2001], le glacio-eustatisme nous semble le seul mécanisme permettant d’expliquer une oscillation marine importante mais de courte durée [Brandt, 1986 ; Dewey et Pitman, 1998]. En effet, le cycle régression-transgression s’étale sur environ deux zones d’ammonites, la lacune sédimentaire en elle-même recouvrant essentiellement les sous-zones à Elisa et Mirabile. Ce premier épisode serait suivi, dans la zone à Tenuicostatum, par une importante perturbation du cycle du carbone responsable d’un effet de serre. Le réchauffement, provoquerait alors la transgression bien connue du Toarcien inférieur, cachetant le hiatus sédimentaire dans la province nord-ouest européenne. L’intervalle de temps correspondant à cette lacune aurait permis à la végétation de coloniser les immenses surfaces nouvellement émergées. C’est le lessivage et l’oxydation de la matière organo-humique et bactérienne accumulée pendant cette période, associée à une élévation de la température, qui aurait enclenché le mécanisme d’anoxie lors du paroxysme de la transgression

Adipose tissue in breast cancer : not an idle bystander but an active participant in breast cancer progression

Background: Adipose tissue is a dynamic organ that secretes a plethora of molecules called adipokines. In breast cancer we find a unique situation were genetically changed cells (the cancer cells) are in close contact with adipocytes. Moreover, obesity is a known negative prognostic marker for postmenopausal breast cancer patients. We hypothesize that adipocyte-derived factors influence breast cancer progression. Materials and methods: Adipose tissue was collected from breast cancer patients undergoing a mastectomy. After macroscopic removal of blood vessels and connective tissue, the adipose tissue was carefully cut into 2-3mm3 pieces and were incubated in specific adipose-tissue culture medium. After 24h, the medium was collected and the quality was checked by determining the concentration of total proteins, leptin, adiponectin, TNFalpha and triglycerides. This conditioned medium of adipose tissue (CM AT) was used for in vitro experimentation with MCF-7 breast cancer cells. Results: Effect of AT on morphology and aggregation: when MCF-7 cells are grown in a culture flask, they tend to form round compact islands. Under influence of CM AT, the islands form sharp edges, the cells in an island can be counted individually and they show scattering. Importantly, despite the major changes in cellular morphology, CM AT removal rescued the compact island formation of MCF-7 cells. In the slow aggregation assay, cells treated with CM AT (and a subtherapeutic concentration of a neutralizing E-cadherin antibody) lost the ability to form compact aggregates. Furthermore, MCF-7 spheroids placed inside adipose tissue showed massive reorganization into an irregularly shaped mass. Effect of AT on proliferation: starting from an equal number of cells and counting them every 2 days, it became clear that MCF-7 cells with CM AT had a higher rate of proliferation than MCF-7 cells in control medium. This stimulation of proliferation was confirmed by cell cycle analysis which revealed a doubling of cells in the G2/M phase, and western blot which showed an upregulation of cyclin A and cyclin E, both positive regulators of the cell cycle. Effect of AT on invasion: a 24h collagen type I invasion assay revealed invasive characteristics of MCF-7 cells treated with CM AT while MCF-7 cells in control conditions are round and non-invasive. In contrast, a transwell collagen test over 14 days was not able to show MCF-7 cells invading the collagen gel under influence of CM AT. However, the growth pattern of MCF-7 cells on the collagen gel was clearly disorganised when compared with the control situation. Conclusion: These findings suggest that adipose tissue-derived factors exert a dramatic selective force on patterning, invasion and growth of MCF-7 breast cancer cells. Unraveling the mechanism behind these observations may provide vital information regarding the link between obesity and poor prognosis in postmenopausal breast cancer