Company Presence as a Marker of Urban Development in France

Since the Industrial Revolution, entreprises have left their imprint on the urban landscape and local government. This paper begins with an historical context on the subject which is followed by an analysis of the different influences of enterprises on town planning, housing and local urban and social policies

Two-Part Tariff Competition With Switching Costs and Sales Agents

This paper study the effects of two-part tariff pricing in a competitive environment with differentiated products and switching costs. This is the case of long distance telephone service, where there is a fixed monthly fee and a charge per call. This is also the case for some financial institutions like mutual funds or pension funds. In many of these industries there are also switching costs. In this environment, markets have reacted by hiring sales agents to switch consumers from one firm to another. Without considering sales agents, social welfare is the same under a two-part tariff regime as under single pricing, but the distribution of surplus is different. When sales agents are introduced to the model, they are able to reduce switching costs, and welfare might increase; but they generate over-switching with respect to the social optimum.

Gauge-invariant massive BF models

Consistent interactions that can be added to a free, Abelian gauge theory comprising a BF model and a finite set of massless real scalar fields are constructed from the deformation of the solution to the master equation based on specific cohomological techniques. Under the hypotheses of analyticity in the coupling constant, Lorentz covariance, spacetime locality, Poincare invariance, supplemented with the requirement on the preservation of the number of derivatives on each field with respect to the free theory, we obtain that the deformation procedure leads to two classes of gauge-invariant interacting theories with a mass term for the BF vector field $A_{\mu }$ with U(1) gauge invariance. In order to derive this result we have not used the Higgs mechanism based on spontaneous symmetry breaking.Comment: 63 page

Antibiotic residues and R-plasmid selection: are in vitro methods good models?

Three clones of E. coli, one of which was harbouring a tetracycline resistance plasmid were inoculated together into the stomach of axenic mice. Without antibiotic selective pressure, the R-Plasmid bearing strain became dominant in the faeces of mice, while the R-plasmid free strain was eliminated. When the R-plasmid bearing strain was given to mice 4 days after the inoculation with the R-plasmid free strain, it was repressed and remained at the stable level of 10(4.5) organisms per g of faeces. But a rapid spread of the R-plasmid was observed, tetracycline resistant bacteria become dominant within one day, and replace the tetracycline sensitive E. coli. The tetracycline resistance plasmid did not disadvantage the mediating strain in the gut, even in the absence of antibiotic pressure. In contrast Lebek and Egger (1983), studying the same strains in vitro, found that in a chemostat the plasmid bearing strain was overgrown by the plasmid free strain. These results strongly suggest that in vitro interactions between E. coli strains cannot be directly extrapolated to in vivo conditions. For the determination of the no-effect level of antibiotic residue on the selection of R-factor in the gut, studies should be made in vivo

Identity and Democracy: Linking Individual and Social Reasoning

Following Amartya Sen\u27s approach, John Davis and Solange Regina Marin look at individual and social reasoning when examining the complex relationship between identity and democracy. They characterize democracy as a process of social or public reasoning that combines the individual reasoning of all citizens. Identity is explained in terms of personal identity, social identity, and individual identity. They argue that democracy in combining the individual reasoning of all citizens responds to individuals’ different personal identity concerns and needs, reflects their shared social identity interests and goals, and accords them rights and responsibilities associated with their many different individual identities

New species of Chariergus White and Ethemon Thomson (Coleoptera, Cerambycidae, Compsocerini

Two new species of Chariergus White are described from Brazil: Chariergus caeruleus, from Bahia, Minas Gerais and Espirito Santo and C. paranaensis., from Parana, Santa Catarina and Rio Grande do SuI. Ethemon brevicorne, sp. n. is described from Argentina (Cordoba). A key to species of Chariergus is added