Games of Incomplete Information and Myopic Equilibria

A new concept of an equilibrium in games is introduced that solves an open question posed by A. Neyman

Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació

Rapport III.8 Les micropolluants dans les eaux souterraines de la région d’Ile-de-France

The use of sophisticated analytical techniques in periodic sanitary control of drinking water made by administrative health authorities allowed the detection of many compounds in concentration of some microgram per liter. These mineral micropollutants (heavy metals) and organic micropollutants (pesticids, aromatic polycyclic hydrocarbons and so on...) are now searched in drinking water as a preventive care ; they indicate an underground water pollution which can became most injurious. Some of them have dangerous effects on health. Results given since a few years in "Ile-de-France" are mentionned by most important aquiferous. Some interpretations particulary on the origin of these micropollutants and on the sanitary aspects, are still to increase. Methods of prevention are proposed : for example the creation of a regional index of localized potential sources of pollutions.Dans le cadre de la surveillance régulière de la qualité des eaux destinées à la consommation humaine par les Directions Départementales de la Santé, la mise en oeuvre de techniques analytiques élaborées a permis la détection d'une large gamme de composés présents à des teneurs de quelques microgrammes par litre. Ces micropolluants : métaux "lourds", pesticides, organohalogénés volatils, hydrocarbures polycycliques aromatiques (HPA) sont actuellement de plus en plus recherchés dans les eaux potables à titre préventif, car ils sont des indices d'une pollution des eaux souterraines qui peut devenir plus nocive. Certains d'entre eux peuvent avoir des effets défavorables sur la santé. Les résultats acquis au cours des dernières années en Ile-de-France seront analysés par aquifère principal. Les interprétations encore à effectuer tant en ce qui concerne l'origine de ces micropolluants que du point de vue sanitaire seront discutées. Enfin, des moyens de prévention, en particulier un inventaire régional des sources de pollutions potentielles localisées, sont proposés.Saout C., Lachaize Jean-Louis. Rapport III.8 Les micropolluants dans les eaux souterraines de la région d’Ile-de-France. In: L'impact des activités humaines sur les eaux continentales. Dix neuvièmes journées de l'hydraulique - Question I, II, III, IV, V et Compte rendu des séances. Tome 3, 1986

Chemical Composition and Antioxidant Activity of Euterpe oleracea Roots and Leaflets

Euterpe oleracea (açaí) is a palm tree well known for the high antioxidant activity of its berries used as dietary supplements. Little is known about the biological activity and the composition of its vegetative organs. The objective of this study was to investigate the antioxidant activity of root and leaflet extracts of Euterpe oleracea (E. oleracea) and characterize their phytochemicals. E. oleracea roots and leaflets extracts were screened in different chemical antioxidant assays (DPPH—2,2-diphenyl-1-picrylhydrazyl, FRAP—ferric feducing antioxidant power, and ORAC—oxygen radical absorbance capacity), in a DNA nicking assay and in a cellular antioxidant activity assay. Their polyphenolic profiles were determined by UV and LC-MS/MS. E. oleracea leaflets had higher antioxidant activity than E. oleracea berries, and leaflets of Oenocarpus bacaba and Oenocarpus bataua, as well as similar antioxidant activity to green tea. E. oleracea leaflet extracts were more complex than root extracts, with fourteen compounds, including caffeoylquinic acids and C-glycosyl derivatives of apigenin and luteolin. In the roots, six caffeoylquinic and caffeoylshikimic acids were identified. Qualitative compositions of E. oleracea, Oenocarpus bacaba and Oenocarpus bataua leaflets were quite similar, whereas the quantitative compositions were quite different. These results provide new prospects for the valorization of roots and leaflets of E. oleracea in the pharmaceutical, food or cosmetic industry, as they are currently by-products of the açaí industry

Oenocarpus bacaba and Oenocarpus bataua Leaflets and Roots: A New Source of Antioxidant Compounds

Native palm trees fruit from the Amazonian rainforest, Oenocarpus bacaba and Oenocarpus bataua, are very often used in the diet of local communities, but the biological activities of their roots and leaflets remain poorly known. Total phenolic content (TPC) and antioxidant activity of root and leaflet extracts from Oenocarpus bacaba and Oenocarpus bataua were assessed by using different chemical assays, the oxygèn radical absorbance capacity (ORAC), the 2,2-diphenyl-l-picrylhydrazyl (DPPH) free radical-scavenging capacity and the ferric-reducing ability of plasma (FRAP). Cellular antioxidant activity and cytotoxicity were also measured in Normal Human Dermal Fibroblasts. The polyphenolic composition of Oenocarpus extracts was investigated by LC-MSn. Oenocarpus leaflet extracts were more antioxidant than root extracts, being at least as potent as Euterpe oleracea berries known as superfruit. Oenocarpus root extracts were characterized by hydroxycinnamic acids (caffeoylquinic and caffeoylshikimic acids), while leaflet extracts contained mainly caffeoylquinic acids and C-glycosyl flavones. These results suggest that leaflets of both Oenocarpus species could be valorized as a new non-cytotoxic source of antioxidants from Amazonia, containing hydroxycinnamic acids and flavonoids, in the pharmaceutical, cosmetic or agri-food industry

Optimization of a DNA Nicking Assay to Evaluate Oenocarpus bataua and Camellia sinensis Antioxidant Capacity

This study was aimed at assessing the DNA damage protective activity of different types of extracts (aqueous, methanolic and acetonic) using an in vitro DNA nicking assay. Several parameters were optimized using the pUC18 plasmid, especially FeSO4, EDTA, solvent concentrations and incubation time. Special attention has been paid to removing the protective and damaging effect of the solvent and FeSO4 respectively, as well as to identifying the relevant positive and negative controls. For each solvent, the optimal conditions were determined: (i) for aqueous extracts, 0.33 mM of FeSO4 and 0.62 mM of EDTA were incubated for 20 min at 37 °C; (ii) for acetone extracts, 1.16% solvent were incubated for 15 min at 37 °C with 1.3 mM of FeSO4 and 2.5 mM of EDTA and (iii) for methanol extracts, 0.16% solvent, were incubated for 1.5 h at 37 °C with 0.33 mM of FeSO4 and 0.62 mM of EDTA. Using the optimized conditions, the DNA damage protective activity of aqueous, methanolic and acetonic extracts of an Amazonian palm berry (Oenocarpus bataua) and green tea (Camellia sinensis) was assessed. Aqueous and acetonic Oenocarpus bataua extracts were protective against DNA damage, whereas aqueous, methanolic and acetonic extracts of Camellia sinensis extracts induced DNA damage

Seeing a ghost? Vigilance and Its drivers in a predator-free world

International audienceVigilance is a key to the early detection of predators, but may be costly if it impairs foraging efficiency. Hence, we would expect vigilance to be suppressed and/or counter-selected in predator-free environments, although this might depend on the environmental drivers influencing perceived predation risk. We studied vigilance in two populations of Sitka black-tailed deer (Odocoileus hemionus sitkensis) on Haida Gwaii (Canada) which have not been exposed to predators since they colonized the study islands approx. 60yr ago. In this context, anti-predator behavior should not have any obvious current benefit. Moreover, its maintenance should be particularly costly in our study populations because these deer have depleted their food resources and, thus, anti-predator behaviors should interfere with time spent searching for scarce resources. We used bait stations equipped with camera traps to assess vigilance under standardized feeding conditions. We expected to observe lower vigilance levels than those observed elsewhere in locations with predators. We investigated how vigilance varied in relation to the amount of bait, the level of visibility, and between day and night. During the day, deer spent, on average, 14% of their time in overt vigilance during foraging bouts, a level similar to, although in the lower range of, values reported at sites where predators are present. Levels of vigilance were lower at night, and decreased with increasing visibility, but not during the day. Deer were less vigilant when bait availability was high, but only when visibility was also high. We discuss why the maintenance of vigilance is here best explained by the ghosts of predators past, and how, at the temporal scale of a few generations, the ecological factors driving vigilance levels might override the absence of significant risk from large predators