Accurate and realistic initial data for black hole-neutron star binaries

This paper is devoted to the computation of compact binaries composed of one black hole and one neutron star. The objects are assumed to be on exact circular orbits. Standard 3+1 decomposition of Einstein equations is performed and the conformal flatness approximation is used. The obtained system of elliptic equations is solved by means of multi-domain spectral methods. Results are compared with previous work both in the high mass ratio limit and for one neutron star with very low compactness parameter. The accuracy of the present code is shown to be greater than with previous codes. Moreover, for the first time, some sequences containing one neutron star of realistic compactness are presented and discussed.Comment: Version including the erratum to be published in Phys. Rev.

Self-gravitating scalar breathers with negative cosmological constant

Breather-type (time-periodic and spatially localized) solutions with spherical symmetry are investigated in a massless scalar field theory coupled to Einstein's gravity with cosmological constant in $d$ spatial dimensions imposing anti de Sitter (AdS) asymptotics on space-time. Using a code constructed with the Kadath library that enables the use of spectral methods, the phase space of breather solutions is explored in detail for $d=3$ and $d=4$. It is found that there are discrete families of solutions indexed by an integer and by their frequency. Using a time evolution code these AdS breathers are found to be stable for up to a critical central density, in analogy to boson stars. Using an analytical perturbative expansion small amplitude breathers are worked out for arbitrary dimensions $d$.Comment: 24 pages, 13 figures, one figure and references added, version accepted for Phys. Rev.

Scalar field breathers on anti-de Sitter background

We study spatially localized, time-periodic solutions (breathers) of scalar field theories with various self-interacting potentials on Anti-de Sitter (AdS) spacetimes in $D$ dimensions. A detailed numerical study of spherically symmetric configurations in $D=3$ dimensions is carried out, revealing a rich and complex structure of the phase-space (bifurcations, resonances). Scalar breather solutions form one-parameter families parametrized by their amplitude, $\varepsilon$, while their frequency, $\omega=\omega(\varepsilon)$, is a function of the amplitude. The scalar breathers on AdS we find have a small amplitude limit, tending to the eigenfunctions of the linear Klein-Gordon operator on AdS. Importantly most of these breathers appear to be generically stable under time evolution.Comment: 30 pages, 22 figure

Wheeling food products around the store... and away: the invention of the shopping cart, 1936-1953

(Analyzes the invention and early development of the shopping cart (supermarket trolley) in the US using original archival sources.)(Analyse l'invention et le développement du chariot de supermarché aux Etats-Unis.

Introduction to spectral methods

This proceeding is intended to be a first introduction to spectral methods. It is written around some simple problems that are solved explicitly and in details and that aim at demonstrating the power of those methods. The mathematical foundation of the spectral approximation is first introduced, based on the Gauss quadratures. The two usual basis of Legendre and Chebyshev polynomials are then presented. The next section is devoted to one dimensional equation solvers using only one domain. Three different methods are described. Techniques using several domains are shown in the last section of this paper and their various merits discussed

Le marketing des similarités. Les produits à marque de distributeur

http://www.cairn.info/resume.php?ID_REVUE=RES&ID_NUMPUBLIE=RES_135&ID_ARTICLE=RES_135_0221This article examines the construction of similarities for two types of distributor brand product. "Me too" distributor brand products are defined as equivalents of national brands but are sold at a lower price. "Marque-Terroir" distributor brands are upmarket, traditional local products whose appearance on supermarket shelves was an innovation. In both cases the construction of similarities is an essential driver of product development which calls for a specific form of organization.Cet article examine la construction des similarités pour deux types de produits à marque de distributeur (MDD), au niveau des produits et au niveau de la gamme. Les MDD " me-too " sont des produits établis comme équivalents des produits à marque nationale mais à un prix inférieur. Les MDD Marque_Terroir sont des produits haut de gamme, " de terroir ", et dont l'apparition sur les linéaires des grandes surfaces a constitué une innovation. Dans les deux cas, la construction des similarités est un ressort fondamental du développement des produits, qui réclame la mise en place d'une organisation spécifique

Fully consistent rotating black holes in the cubic Galileon theory

Configurations of rotating black holes in the cubic Galileon theory are computed by means of spectral methods. The equations are written in the 3+1 formalism and the coordinates are based on the maximal slicing condition and the spatial harmonic gauge. The black holes are described as apparent horizons in equilibrium. It enables the first fully consistent computation of rotating black holes in this theory. Several quantities are extracted from the solutions. In particular, the vanishing of the mass is confirmed. A link is made between that and the fact that the solutions do not obey the zeroth-law of black hole thermodynamics

Climatiser le marché. Les contributions des marketings de l'ambiance et de l'atmosphère

http://www.ethnographiques.org/2004/Grandclement.htmlThis article first argues that the proliferation of air conditioning in contemporary marketplaces has facilitated increased control over ambient dimensions of markets. Then, the article shows that marketing researchers are becoming aware of this means of action over markets. It offers a literature review of two current trends of marketing research concerning ambiance and atmosphere. Finally, it is proposed that the notion of ambiance in markets is not an outdated category of market ethnography. Ambiences and atmospheres must, on the contrary, be studied by market anthropologists in addition to other market mediations. In conclusion, it is suggested that atmospheric mediation is a mediation which attempts to transform by-passers into greedy consumers.Partant du constat que la généralisation de l'air conditionné dans les espaces commerciaux a accrû le contrôle de la qualité des ambiances marchandes, cet article propose une revue de la littérature marketing consacrée à cet aspect des marchés. Il est ainsi suggéré que les catégories de l'atmosphère et de l'ambiance n'appartiennent pas à un registre périmé de l'ethnographie des marchés. Elles doivent au contraire être étudiées en anthropologie économique au même titre que les autres médiations marchandes. En conclusion, il est fait l'hypothèse que la médiation atmosphérique est une médiation susceptible de faire advenir la passion consommatrice chez le badaud

Climatiser le marché. Les contributions des marketings de l'ambiance et de l'atmosphère

Partant du constat que la généralisation de l'air conditionné dans les espaces commerciaux a accrû le contrôle de la qualité des ambiances marchandes, cet article propose une revue de la littérature marketing consacrée à cet aspect des marchés. Il est ainsi suggéré que les catégories de l'atmosphère et de l'ambiance n'appartiennent pas à un registre périmé de l'ethnographie des marchés. Elles doivent au contraire être étudiées en anthropologie économique au même titre que les autres médiations marchandes. En conclusion, il est fait l'hypothèse que la médiation atmosphérique est une médiation susceptible de faire advenir la passion consommatrice chez le badaud.Marketing; grande distribution; atmosphère; sociologie économique