[en] The protection of the environment implies to make a complete overhaul of our production means and uses of energy. The realistic solution appears to be an optimized mix of the present sources of energy because it will be unreasonable to put all the stakes on alternative energy sources like hydrogen or solar energy or biomass or... without being sure of their efficiency for they still need important research work to be validated. The worldwide reserves of coal represent 160 years of consumption at present combustion rate but the combustion of coal releases 72% more CO₂ than that of natural gas. The use of coal has not to be barred from the mix but adequate solutions have to be found. A dozen of European projects concerning the trapping and the disposal of CO₂ in geological layers are being developed. One of them is situated on the Lacq site in south-western France. This facility will enter into service in 2009 and will have the capacity to process and dispose 200 tonnes of CO₂ per day in an exhausted methane deposit. The protection of the environment also means a sound air to breathe. The public began aware of this necessity in the eighties when the fight against acid rains culminated. Now the industrial sector invests millions euros annually to comply with tougher regulations concerning sulfur, ozone, volatile organic compounds or heavy metals releases. The protection of the environment also means an adequate processing of the by-products of industrial activities. For instance, it is little known that oil extraction produces generally more water than oil. The water can be either injected back into the reservoir or disposed into the surface natural network, and the latter must comply with European regulations that impose a safe chemical composition but also a neutral ecological impact for the disposed water. (A.C.)

[en] Short communication

No abstract available

[en] A recently proposed generating functional allows the construction of the full set of n-point Green functions in QCD at high temperature and at distances larger than 1/(gT). One may then learn how the system maintains its thermal equilibrium in the quantum field theory approach, i.e., which process compensates for the important dissipation due to collisions. This system may be characterized by quantities which have a classical limit. One finds that the fluctuations of the colour field are not Gaussian ones. A comparison is made with Boedeker's classical approach where a random noise is the source of fluctuations

[en] General Ward identities on the lattice for Wilson fermions are written in terms of the Green functions measured in numerical simulations. In the pion sector, the emphasis is on K=K_c at intermediate values of the coupling constant. An argument is made similar to the one leading to Adler's zeroes, and tests of restoration of chiral symmetry are proposed which are accessible to numerical simulations. (orig.)

[en] Wilson's action for fermions on a lattice is compared to the continuum action in a model obtained from the chiral Gross-Neveu model by performing a chiral transformation. The local definition of the axial current leads to two anomalies unrelated by the constraint of Lorentz invariance. In the large-N limit, the mass counterterm of the action is determined; this term is unnecessary in the Osterwalder-Seiler regularization. An expansion in the fermion propagator and in the axial current coupling may be formulated and summed to all orders for large N. (orig.)

[en] COGEMA Resources Inc. (part of the Areva Group) is a Canadian company with its head office in Saskatoon, Saskatchewan. It owns and operates mining and milling facilities in Northern Saskatchewan, where it produces uranium concentrate. Understanding groundwater flow at the regional scale underlies long term predictions for the performance of decommissioned tailings management facilities and waste rock disposal sites. A three dimensional regional groundwater flow model was developed to update and integrate the hydrogeological information relevant to environmental assessments or licensing analyses of the JEB, Sue, McClean Lake and Midwest sites operated by COGEMA Resources Inc. in Northern Saskatchewan. The regional model is based on a comprehensive geological and hydrogeological database, including more than 4200 exploration boreholes, 1000 hydraulic conductivity test results and water levels recorded at approximately 150 monitoring wells. Monthly surface water and groundwater quality data are also available from approximately 1996. The model was calibrated on both pre-mining and dewatered conditions. It was used to identify the hydraulic role of key regional features, including numerous surface water bodies, major fracture/fault zones and the sandstone unit, which constitutes the main aquifer over the study area. The regional model was also used to identify natural boundaries for local sub-models, which were extracted for the purpose of predicting post-decommissioning flow and contaminant transport from the Sue C Pit waste rock disposal area and from the JEB Tailings Management Facility. A follow-up programme was identified based on the data analysis and the results of the regional model. The follow-up programme includes research-related and ongoing actions, with the objective of improving the robustness of model predictions for regulatory purposes and optimizing monitoring as data continues to be collected. (author)

[en] The transverse momentum structure of multiparticle production phenomena in the perturbative reggeon calculus is investigated. It is found that, concerning the transverse correlation < psub(c).psub(d)>(ysub(c),ysub(d)) in the central region, the cutting rules of Abramovskii, Gribov, Kancheli are modified and that the inclusive long-range transverse correlation is asymptotically zero to the second order in the triple-pomeron coupling constant. (Auth.)

[en] A recent parton interpretation of the supercritical pomeron is applied to scattering off nuclei. Predictions are made for elastic and inelastic diffraction, inclusive densities and correlations, and for hard scattering. (Auth.)

[en] An expansion in the fermion propagator is formulated for the N-species Gross-Neveu model in the large-N limit. Different regularisation schemes may be adopted and we compare two. We find that a continuum momentum cut-off is easiest to work with and automatically avoids spurious fermionic states which afflict a naive lattice formulation. Chiral symmetry is broken at zeroth order and the resulting expansion is inverse powers of g²N simplifies considerably for large N. In this limit the strong-coupling expansion may be summed to all orders. Extrapolation techniques, like Pade approximants, are not needed. Using a momentum cut-off we recover all the exact results previously derived by summing weak-coupling expansions. (orig.)