Price and Brand Competition between Differentiated Retailers: A Structural Econometric Model

We develop a model of competition between retailer chains with a structural estimation of the demand and supply in the supermarket industry in France. In the model, supermarkets compete in price and brand offer over all food products to attract consumers, in particular through the share of private labels versus national brands across all their products. Private labels can serve as a differentiation tool for the retailers in order to soften price competition. They may affect the marginal costs of all products for the retailer because of eventual quality differences and also by helping retailers to obtain better conditions from their manufacturers. Differentiation is taken into account by estimating a discrete-continuous choice model of demand where outlet choice and total expenditures are determined endogenously. On the supply side, we consider a simultaneous competition game in brand offer and price between retailers to identify marginal costs. After estimation by simulated maximum likelihood, the structural estimates allow to simulate the effect on the equilibrium behavior of retailer chains of a demand shock through an increase in transportation costs for consumers and a merger between two retailer chains.

Quantum oscillations and upper critical magnetic field of the iron-based superconductor FeSe

Shubnikov-de Haas (SdH) oscillations and upper critical magnetic field ($H\_{c2}$) of the iron-based superconductor FeSe ($T\_c$ = 8.6 K) have been studied by tunnel diode oscillator-based measurements in magnetic fields of up to 55 T and temperatures down to 1.6 K. Several Fourier components enter the SdH oscillations spectrum with frequencies definitely smaller than predicted by band structure calculations indicating band renormalization and reconstruction of the Fermi surface at low temperature, in line with previous ARPES data. The Werthamer-Helfand-Hohenberg model accounts for the temperature dependence of $H\_{c2}$ for magnetic field applied both parallel (\textbf{H} $\|$ $ab$) and perpendicular (\textbf{H} $\|$ $c$) to the iron conducting plane, suggesting that one band mainly controls the superconducting properties in magnetic fields despite the multiband nature of the Fermi surface. Whereas Pauli pair breaking is negligible for \textbf{H} $\|$ $c$, a Pauli paramagnetic contribution is evidenced for \textbf{H} $\|$ $ab$ with Maki parameter $\alpha$ = 2.1, corresponding to Pauli field $H\_{P}$ = 36.5

Collapse of critical nematic fluctuations in FeSe under pressure

We report the evolution of the electronic nematic susceptibility in FeSe via Raman scattering as a function of hydrostatic pressure up to 5.8 GPa where the superconducting transition temperature $T_{c}$ reaches its maximum. The critical nematic fluctuations observed at low pressure vanish above 1.6 GPa, indicating they play a marginal role in the four-fold enhancement of $T_{c}$ at higher pressures. The collapse of nematic fluctuations appears to be linked to a suppression of low energy electronic excitations which manifests itself by optical phonon anomalies at around 2 GPa, in agreement with lattice dynamical and electronic structure calculations using local density approximation combined with dynamical mean field theory. Our results reveal two different regimes of nematicity in the phase diagram of FeSe under pressure: a d-wave Pomeranchuk instability of the Fermi surface at low pressure and a magnetic driven orthorhombic distortion at higher pressure.Comment: 7 pages, 4 figures. Supplementary Material available upon reques

Programmation architecturale et architecture virtuelle

La programmation architecturale constitue souvent la première étape d’un ensemble plus vaste et complexe nécessaire à l’édification d’un bâtiment. Cet article vise à dégager, à partir de la nouvelle pratique de l’architecture virtuelle, les éléments essentiels qui différencient sa programmation architecturale de celle d’une architecture traditionnelle. L’exposé introduit dans un premier temps la programmation architecturale, puis définit l’architecture virtuelle, pour ensuite exposer l’application de la programmation à l’architecture virtuelle.Architectural programming is often the first stage of a bigger and more complex set of necessary actions to building edification. This article aims at spotting from the new practice of virtual architecture, the essential elements, which differentiate its architectural programming from a traditional architecture. The paper introduces initially programming, and then defines virtual architecture, for then describing the application of programming to virtual architecture

La politique culturelle des villes québécoises face à la récente réforme municipale

L’article traite de l’impact des fusions municipales sur le secteur culturel municipal dans les huit villes de plus de 100 000 habitants, résultat des fusions de 2002, soit celles de Québec, Montréal, Sherbrooke, Gatineau, Lévis, Longueuil, Trois-Rivières et Saguenay. L’examen des compétences en matière culturelle des huit villes fusionnées ainsi que l’examen de leurs politiques culturelles permettent de repérer la présence de liens de renforcement mutuel entre la réorganisation municipale et le domaine culturel. Plus encore, il semblerait que la restructuration municipale ait permis de poser les bases d’un développement incrémental et prometteur du secteur culturel municipal, propres à chacune des villes.This paper discusses the impact of the municipal mergers of 2002 on public policies in the area of the municipal cultural sector for the eight Quebec cities of more than 100,000 inhabitants. An examination of cultural responsibilities and activities in Quebec City, Montreal, Sherbrooke, Gatineau, Lévis, Longueuil, Trois-Rivières and Saguenay, on the one hand, and an analysis of their cultural policies, on the other, leads us to conclude that the links between public cultural initiatives and the municipal territories were weak until the municipal reorganisation. The new regional reality of each city will help foster the development of the municipal cultural sector

Price and Brand Competition between Differentiated Retailers: A Structural Econometric Model

We develop a model of competition between retailer chains with a structural estimation of the demand and supply in the supermarket industry in France. In the model, supermarkets compete in price and brand offer over all food products to attract consumers, in particular through the share of private labels versus national brands across all their products. Private labels can serve as a differentiation tool for the retailers in order to soften price competition. They may affect the marginal costs of all products for the retailer because of eventual quality differences and also by helping retailers to obtain better conditions from their manufacturers. Differentiation is taken into account by estimating a discrete-continuous choice model of demand where outlet choice and total expenditures are determined endogenously. On the supply side, we consider a simultaneous competition game in brand offer and price between retailers to identify marginal costs. After estimation by simulated maximum likelihood, the structural estimates allow to simulate the effect on the equilibrium behavior of retailer chains of a demand shock through an increase in transportation costs for consumers and a merger between two retailer chains

Price and Brand Competition between Differentiated Retailers: A Structural Econometric Model

We develop a model of competition between retailer chains with a structural estimation of the demand and supply in the supermarket industry in France. In the model, supermarkets compete in price and brand offer over all food products to attract consumers, in particular through the share of private labels versus national brands across all their products. Private labels can serve as a differentiation tool for the retailers in order to soften price competition. They may affect the marginal costs of all products for the retailer because of eventual quality differences and also by helping retailers to obtain better conditions from their manufacturers. Differentiation is taken into account by estimating a discrete-continuous choice model of demand where outlet choice and total expenditures are determined endogenously. On the supply side, we consider a simultaneous competition game in brand offer and price between retailers to identify marginal costs. After estimation by simulated maximum likelihood, the structural estimates allow to simulate the effect on the equilibrium behavior of retailer chains of a demand shock through an increase in transportation costs for consumers and a merger between two retailer chains

Spatial sampling design for sediment quality assessment in estuaries

Unusual difficulties are encountered when characterizing the spatial distribution of the properties that collectively define the state of estuaries. Due to the variability of these estuarine conditions, greater sampling efforts are often necessary to describe estuarine environments, as compared to other aquatic systems. That is why in coastal management studies, where the collection of data is sometimes very difficult and time-consuming, a robust sampling strategy is essential. The aim of this study is to design a spatial sampling strategy for estuarine sediments, using prior information on the spatial variation of sediment granulometry. Systematic unaligned sampling with a grid cell size of 750 × 500 m was chosen on the basis of semi-variogram analysis, and was shown to have distinct advantages. This design was sampled for sediment parameters using a GPS-receiver and mapped within the digitized shoreline of the estuary. The estuary shoreline was digitized on the basis of aerial ortho-photography with tidal ebb determination. The sampling is intended to define the boundaries of environmental management areas for the Sado Estuary, situated on the west coast of Portugal. The research represents one of the initial phases in the development of a Sado Estuary environmental management system integrated into a Geographic Information System.info:eu-repo/semantics/publishedVersio

Psoralen and ultraviolet A light treatment directly affects phosphatidylinositol 3-kinase signal transduction by altering plasma membrane packing

Psoralen and ultraviolet A light (PUNTA) are used to kill pathogens in blood products and as a treatment of aberrant cell proliferation in dermatitis, cutaneous T-cell lymphoma, and graft versus-host disease. DNA damage is well described, but the direct effects of PUVA on cell signal transduction are poorly understood. Because platelets are anucleate and contain archetypal signal transduction machinery, they are ideally suited to address this. Lipidomics on platelet membrane extracts showed that psoralen forms adducts with unsaturated carbon bonds of fatty acyls in all major phospholipid classes after PUVA. Such adducts increased lipid packing as measured by a blue shift of an environment-sensitive fluorescent probe in model liposomes. Furthermore, the interaction of these liposomes with lipid order-sensitive proteins like amphipathic lipid-packing sensor and a-synuclein was inhibited by PUVA. In platelets, PUVA caused poor membrane binding of Akt and Bruton's tyrosine kinase effectors following activation of the collagen glycoprotein VI and thrombin protease-activated receptor (PAR) 1. This resulted in defective Akt phosphorylation despite unaltered phosphatidylinositol 3,4,5-trisphosphate levels. Downstream integrin activation was furthermore affected similarly by PUVA following PAR1 (effective half-maximal concentration (EC), 8.4 +/- 1.1 versus 4.3 +/- 1.1 mu M) and glycoprotein VI (EC50, 1.61 +/- 0.85 versus 0.26 +/- 0.21 mu g/ml) but not PAR4 (EC50, 50 +/- 1 versus 58 +/- 1 mu m) signal transduction. Our findings were confirmed in T-cells ftom graft-versus-host disease patients treated with extracorporeal photopheresis, a form of systemic PUVA. In conclusion, PUVA increases the order of lipid phases by covalent modification of phospholipids, thereby inhibiting membrane recruitment of effector kinases