Playing And Learning Without Borders: A Real-time Online Play Environment

ENJEUX-S is a development/research project financed by the AAP program (Industry Canada) from November 2004 to November 2006. Its objectives are to develop and validate an advanced games and simulations environment, based on a Web Services and telecommunications architecture to support the development and experimental activities of the generic game and simulation shells of the SAGE portal. This environment will support multi-user functions by means of transactional and interpersonal types of interactivity. Relying on a Web Services model, the environment will allow real-time interaction (digital telephony or videoconferencing) and animation (video, voice, sound, graphics or images). This advanced environment will provide transparent support for games and simulations developed by means of the generic shells implemented in the SSHRC-INE project. The core of the ENJEUX-S project integrates the components of real-time communication in the domain of Internet-based educational games and simulations. This integration - one of the original aspects of this project - enables the utilisation of enhanced educational situations (feedback, on-line dialogue, immediate assistance, shared strategies, help, etc.), where the real world meets the virtual world so as to investigate simple or complex 2-D or 3-D learning situations. On the one hand, the addition of multimedia components to educational games and simulation interfaces (interactivity) and, on the other hand, the instantaneous and simultaneous interactions provided by the proposed architecture, allow the handling of educational situations where geographically dispersed users will be able to act together, make concurrent decisions and cooperate among themselves all in real-time, thus emphasizing the emotional, communicative and social potential of educational situations. In summary, the environment developed in the ENJEUX-S project aims at developing user-friendly, on-line training situations, based on dialogue and intervention in teleconferencing mode (virtual face-to-face). This workshop will first present the design stages underlying the development of this environment, followed by examples of the operation of the environment using games and simulations developed within the SAGE project. Finally, participants will be invited to comment on the proposed environment with respect to their training requirements

A short-term divergent selection for resistance to Teladorsagia circumcincta in Romanov sheep using natural or artificial challenge

This experiment was conducted to assess the efficiency of selection on the basis of response to artificial challenges in order to breed sheep resistant to natural infection. A short-term divergent selection process was designed to estimate the genetic parameters of these two traits. Two flocks, including 100 Romanov ram lambs each, were challenged in 1990 when they were 6 months old. One flock received three artificial infections with 20 000 third-stage Teladorsagia circumcincta larvae, at intervals of 7 weeks. Faecal egg counts (FEC) were performed on Days 22, 25 and 28 post infection (p.i.) and the animals were drenched on Day 28 p.i. The other flock was grazed for 5 months on a pasture contaminated with the same species. Faecal samples were taken from the lambs at similar ages. About 5 rams with the lowest FEC and 5 with the highest FEC were selected in each flock and mated with unselected ewes. Their offspring (200 animals) were challenged in 1992, half in the same way as their sires, and the other half by the other method. Because of a drought in the summer of 1990, it was necessary to repeat part of the experiment, and in 1992 the 5 and 8 rams with the lowest and highest FEC, respectively, were selected from the offspring challenged on the pasture in 1992 and were mated with unselected ewes. Their progeny (about 80 animals) were challenged in 1994, half by natural infection, half by artificial infection. The mean FEC of the flock increased from the first to the third artificial infection. The natural infection was highly variable in different years, reflecting the difficulty of assessing resistance using this mode of challenge. Genetic parameters were estimated using animal models and REML solutions. The repeatabilities of the FEC following artificial and natural infection were 0.49 and 0.70 respectively within a period of one week, and 0.22 and 0.41 respectively for periods separated by intervals of 7 weeks; the heritabilities of the single egg count were 0.22 and 0.38 respectively. The genetic correlation was 0.87: the FEC recorded under natural or artificial infection appear to depend on the same genetic potential

Writing and erasing multicolored information in diarylethene-based supramolecular gels

A facile cocktail approach implying the mixing of diarylethene (DAE) photoswitches and low molecular weight gelators (LMWG) is presented. The photoresponsive gels exhibit multicolored emission that can be precisely controlled by different light exposure schemes (wavelength and dose), applicable forfluorescence patterning/writing. Including also a blue-emitting fluorophore allows for tri-chromatic color tuning of the emission via multistep energy transfer reactions, which in turn yields a non-linear response between the emission spectra and the light dose. This feature is highly desired in data security and anti-counterfeiting contexts. The information written in the gels can be conveniently erased by light, mass diffusion, or shaking; the latter being due to the thixotropic properties of the gels

Fractionation of lead in soil by isotopic dilution and sequential extraction

‘Reactivity’ or ‘lability’ of lead is difficult to measure using traditional methods. We investigated the use of isotopic dilution with 204Pb to determine metal reactivity in four soils historically contaminated with contrasting sources of Pb, including (i) petrol-derived Pb, (ii) Pb/Zn minespoil, (iii) long-term sewage sludge application and (iv) 19th century urban waste disposal; total soil Pb concentrations ranged from 217 to 13 600 mg kg–1. A post-spike equilibration period of 3 days and suspension in 5.0 × 10–4 M ethylenediaminetetraacetic acid provided reasonably robust conditions for measuring isotopically exchangeable Pb. However, in acidic organic soils a dilute Ca(NO3)2 electrolyte may be preferable to avoid mobilisation of ‘non-labile’ Pb. Results showed that the reactive pool of soil Pb can be a large proportion of the total soil lead content but varies with the original Pb source. A comparison of isotopic exchangeability with the results of a sequential extraction procedure showed that (isotopically) ‘non-labile’ Pb may be broadly equated with ‘residual’ Pb in organic soils. However, in mineral soils the ‘carbonate’ and ‘oxide-bound’ Pb fractions included non-labile forms of Pb. The individual isotopic signatures of labile and non-labile Pb pools suggested that, despite prolonged contact with soil, differences between the lability of the original contaminant and the native soil Pb may remain

Covalent incorporation of diphenylanthracene in oxotriphenylhexanoate organogels as a quasi-solid photon upconversion matrix

Triplet-triplet annihilation photon upconversion (TTA-UC) in solid state assemblies are desirable since they can be easily incorporated into devices such as solar cells, thus utilizing more of the solar spectrum. Realizing this is, however, a significant challenge that must circumvent the need for molecular diffusion, poor exciton migration, and detrimental back energy transfer among other hurdles. Here, we show that the above-mentioned issues can be overcome using the versatile and easily synthesized oxotriphenylhexanoate (OTHO) gelator that allows covalent incorporation of chromophores (or other functional units) at well-defined positions. To study the self-assembly properties as well as its use as a TTA-UC platform, we combine the benchmark couple platinum octaethylporphyrin as a sensitizer and 9,10-diphenylanthracene (DPA) as an annihilator, where DPA is covalently linked to the OTHO gelator at different positions. We show that TTA-UC can be achieved in the chromophore-decorated gels and that the position of attachment affects the photophysical properties as well as triplet energy transfer and triplet-triplet annihilation. This study not only provides proof-of-principle for the covalent approach but also highlights the need for a detailed mechanistic insight into the photophysical processes underpinning solid state TTA-UC

Ecological goods and services and agroforestry : the benefits for farmers and the interests for society

Paper presented at the 11th North American Agroforesty Conference, which was held May 31-June 3, 2009 in Columbia, Missouri.In Gold, M.A. and M.M. Hall, eds. Agroforestry Comes of Age: Putting Science into Practice. Proceedings, 11th North American Agroforestry Conference, Columbia, Mo., May 31-June 3, 2009.The main objective of this project is to estimate the social value of environmental goods and services (EG&S) generated by agroforestry practices and to evaluate the profitability of these practices for agricultural producers and for society. Two agroforestry practices are considered: riparian buffer zones and windbreaks. Moreover, the situations in two representative agricultural watersheds serve our analysis (Chateauguay and Fouquette watersheds). Among the numerous EG&S that are provided through agroforestry practices, nine have been chosen for this study: agriculture-related odors, aestheticism of the landscape, terrestrial biodiversity, surface water quality, carbon sequestration, road accidents, clearing snow from roads, treatment of drinking water and wild pollinating insects. Several economic valuation methods have been used, such as hedonic pricing value, benefit transfer, productivity method or experimental economics.Jean Nolet (1), Claude Sauve_ (1), Maria Olar (1), Maribel Hernandez (1), Marjolaine Mondon (1), Caroline Simard (1), Louis-Samuel Jacques (1), Andr� V�zina (2), Nathan De Baets (2), Maud Ablain (3), and Pierre Etcheverry (3) ; 1. EcoRessources Consultants, 825, rue Raoul-Jobin, Qu�bec, QC, Canada, G1N 1S6. 2. Activa Environnement Inc., 106, rue Industrielle, New Richmond (Qu�bec), G0C 2B0. 3. Centre d'expertise sur les produits agroforestiers (CEPAF), 235, route 230 ouest, La Pocati�re, QC, Canada, G0R 1Z0.try pIncludes bibliographical references

Spinless impurities in high Tc cuprates: Kondo-like behavior

We compare the effects of in-plane non magnetic Li$^{+}$ and Zn$^{2+}$ impurities on the normal state of high-T$_{c}$ cuprates. Y NMR shows that the extra hole introduced by Li is not localized in its vicinity. The Tc depression and induced moments on near neighbour Cu sites of Zn or Li are found identical. These universal effects of spinless impurities establish the major influence of the spin perturbation with respect to the charge defect. The susceptibility of the induced moment measured by Li NMR displays a 1/(T+Theta) behavior. Theta increases with doping up to about 200 K in the overdoped regime. We attribute this to a "Kondo like" effect.Comment: To appear in Phys.Rev.Lett. (22 nov. 99) Minor modifications compared to previous version. 8 pages (4 pages for text + 4 figures