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[en] The opening of the US natural gas market to competition is followed by deep changes in the implemented regulations for an efficient organization and operation of the gas industry. The transformations of the industrial structures and the strategic behavior of the actors characterize the mutations of the gas markets in the USA. The aim of this paper is to transcribe in a synthetic form the characteristics of the gas market in North America and to model the structure of the industry in this sector opened to competition in its back-end. Two main questions are analyzed: the role and position of the former monopoly (utility) in this back-end market (should the local distribution companies continue to sell gas to end users?), and what kind of regulation should be implemented by the authorities in order to avoid the former monopoly to use its market power and make excessive profits. The analysis is made in two steps: the first part explains the hypotheses of the analysis using the characteristics of the North American market. It presents the general framework of the model and explains the two 'regulatory scenarios' retained in the study. The main steps of the resolution of the model are detailed in the second part. (J.S.)
[en] The process of deregulation in network industries, in particular in the electric sector, raises the problem of financing the Universal Service Obligations (USO) corresponding to the production, transport and distribution operations. In this paper, we study three ways of funding for an USO of production, especially the 'green' electricity development; the financing with cross-subsidies, the implementation of a fund (financing by a tax) and finally a voluntary funding system by direct subscriptions of consumers. We notably show that this last one Pareto dominates mostly, from a welfare point of view, the other scenarios. (authors)
[en] The transition towards a more competitive regime in network industries (and specially in electricity sector) raises the relevant question of funding for the Universal Service Obligations (USOs). Our paper focuses on two ways of funding for universal service and equal treatment obligations ''Ubiquity and Nondiscrimination constraints, UND'': the funding through access charge (CS regime) or taxation (T regime). Using a network model including competition between a historical monopoly (in charge for the USOs) and an entrant, we obtain some results concerning gains and losses of social welfare due to those mechanisms. We show that most of the time it is socially better to let the historical monopoly be active whatever the type of funding for USOs applying, and whatever profitability of the firms is. However, when the entrant is active, we can highlight that the introduction of the T regime (compared to the CS one) implies either welfare deterioration or an entry prevention strategy by the historical firm. Therefore, the T regime could not be an argument for the regulator to promote vertical separation of the historical firm (according to the European community line). (author)
[en] The report prepared for the European Commission on the initial results of the competitive natural gas market, which opened in August 2000, identified various technical and organizational problems. The report highlighted the preponderant place occupied by historical natural gas suppliers in the market place and the barriers they have constructed in their former exclusively held territories, with the obvious intention of limiting the entry of new suppliers into the market. The authors conclude that to avoid such competition-limiting behaviour, it will be necessary to limit the power of the existing supply firms. To lay the foundation for a series of recommendations the authors first examine the positions occupied by the various actors in the gas supply chain, followed by a review of the principal factors affecting the European natural gas market, paying special attention to existing regulations. Based on the literature on vertical integration of markets, the final section makes certain proposals concerning the separation of the gas production and distribution functions and the resulting behaviour of the various actors in terms of their respective positions along the natural gas supply chain. Recommendations are also made regarding possible future directions in market regulations. 25 refs., 1 tab. figs
[en] Both the organization and financing of public service activities have been modified after the opening of energy networks to competition. These activities were traditionally financed by cross subsidies among consumers or by public subsidies (taxation). In a competitive framework two main solutions are generally adopted: financing by a special fund (all producers have to pay), financing by access fees on the transmission and distribution network (T.P.A.). Other solutions are nevertheless possible and this paper lays emphasis on decentralized financing by a voluntary contribution of consumers. This system is particularly adapted when the promotion of 'green electricity' has to be implemented (electricity produced by renewable sources). This system enables suppliers to know consumers' preferences and their ability to pay. (authors)
[en] This paper (i) highlights the role that unit subsidies can play in the compensation scheme of a Universal Service Obligation (USO), and (ii) shows that welfare may be reduced when regulation requires accounting separation of network activities for vertically integrated USO providers. This suggests that accounting separation should be avoided when a USO is implemented. (authors)
[en] Recently, Warm (keV scale) Dark Matter emerged impressively over CDM (Cold Dark Matter) as the leading Dark Matter candidate. In the context of this new Dark Matter situation, which implies novelties in the astrophysical, cosmological and keV particle physics context, this 16. Paris Colloquium 2012 is devoted to the LambdaWDM Standard Model of the Universe. The topics of the colloquium are as follows: -) observational and theoretical progress on the nature of dark matter: keV scale warm dark matter, -) large and small scale structure formation in agreement with observations at large scales and small galactic scales, and -) neutrinos in astrophysics and cosmology. This document gathers the slides of the presentations.
[en] Swift, a satellite devoted to the study of cosmic gamma-ray bursts (GRBs), is now fully operational and detects about 100 GRBs per year, as the first year of operation demonstrated. Since its launch (20 November 2004), Swift has monitored with the narrow-field X-ray telescope (XRT) 75 afterglows (out of 97 GRBs), starting just a few minutes after the GRB onset. Together with the events detected by HETE-II and INTEGRAL, Swift gives us a unique position to unveil the details of these enigmatic events, which likely identify the birth of black holes. GRBs are also useful cosmological tools, and can be used as powerful, distant beacons to trace the history and evolution of the early Universe. All of this can be accomplished by the use of Swift, coupled to large ground-based telescopes. In this article we describe some of the fresh, exciting results obtained in the field. (orig.)
[en] GRB080319B reached fifth optical magnitude during the burst prompt emission. Thanks to the Very Large Telescope (VLT)/Ultraviolet and Visual Echelle Spectrograph (UVES) rapid response mode, we observed its afterglow just 8m:30s after the gamma-ray burst (GRB) onset when the magnitude was R ∼ 12. This allowed us to obtain the best signal-to-noise (S/N), high-resolution spectrum of a GRB afterglow ever (S/N per resolution element ∼50). The spectrum is rich of absorption features belonging to the main system at z = 0.937, divided in at least six components spanning a total velocity range of 100 km s-1. The VLT/UVES observations caught the absorbing gas in a highly excited state, producing the strongest Fe II fine structure lines ever observed in a GRB. A few hours later, the optical depth of these lines was reduced by a factor of 4-20, and the optical/UV flux by a factor of ∼60. This proves that the excitation of the observed fine structure lines is due to 'pumping' by the GRB UV photons. A comparison of the observed ratio between the number of photons absorbed by the excited state and those in the Fe II ground state suggests that the six absorbers are ∼2-6 kpc from the GRB site, with component I ∼ 3 times closer to the GRB site than components III-VI. Component I is characterized also by the lack of Mg I absorption, unlike all other components. This may be both due to a closer distance and a lower density, suggesting a structured interstellar matter in this galaxy complex.