Investigation of the Praesepe cluster. III. Radial velocity and binarity of the F5-K0 Klein-Wassink stars

Coravel observations of 103 F5-K0 stars in the Praesepe cluster yielded 24 spectroscopic binaries (3 are non-members), and 20 orbits were determined, with periods from 4 to 7400 days. Based on a complete sample in the colour range 0.40 < B-V < 0.80 (80 stars, including KW 244 = TX Cnc), the companion star fraction CSF = 0.45. The percentage of spectroscopic binaries with P < 1000d is 20% (16/80). The combined photometric and spectroscopic analysis showed that 12 among 18 single-lined spectroscopic binaries are located within the "single" star sequence in the (V,B-V) diagram and cannot be detected by the photometric analysis in the UBV system. In addition, seven photometrically analysed binaries were not detected with the radial velocity observations, but are confirmed members. The number of single:binary:triple stars is 47:30:3.Comment: 10 pages, 3 tables, 7 eps figures. Accepted for A&A. LaTe

On the Extension of Pseudo-Boolean Functions for the Aggregation of Interacting Criteria

The paper presents an analysis on the use of integrals defined for non-additive measures (or capacities) as the Choquet and the \Sipos{} integral, and the multilinear model, all seen as extensions of pseudo-Boolean functions, and used as a means to model interaction between criteria in a multicriteria decision making problem. The emphasis is put on the use, besides classical comparative information, of information about difference of attractiveness between acts, and on the existence, for each point of view, of a ``neutral level'', allowing to introduce the absolute notion of attractive or repulsive act. It is shown that in this case, the Sipos integral is a suitable solution, although not unique. Properties of the Sipos integral as a new way of aggregating criteria are shown, with emphasis on the interaction among criteria.

Short Note on the Unemployment Rate of the “French overseas regionsâ€

This article analyzes the hysteresis hypothesis in the unemployment rates of the four “French overseas regions†(Guadeloupe, Martinique, Guyana, Reunion) [FORs] over the period 1993-2008. We use standard univariate and panel unit root tests, among them Choi (2006) and Lopez (2009) that account for cross-sectional dependence and have improved performance when the number of countries and the time dimension of the data are limited. Our results cannot reject the null hypothesis of a unit root and so find evidence supporting hysteresis in the unemployment rates for the FORs.Hysteresis, Unemployment, Panel unit root test, cross-section dependence, convergence

Nonuniform Transformation Field Analysis

The exact description of the overall behavior of composites with nonlinear dissipative phases requires an infinity of internal variables. Approximate models involving only a finite number of those can be obtained by considering a decomposition of the microscopic anelastic strain field on a finite set of transformation fields. The Transformation Field Analysis of Dvorak [Proc. R. Soc. Lond. A 437 (1992) 311] corresponds to piecewise uniform transformation fields. The present theory considers nonuniform transformation fields. Comparison with numerical simulations shows the accuracy of the proposed model

Opportunisme ou équité ? Le cas des contrats d'approvisionnement de défense

How are extra costs resulting from the occurrence of unanticipated risks allocated in a procurement setting? This paper develops a theoretical framework combining transaction cost economics with equity theory in order to explain why parties endorse cooperative strategies, basically a 50-50 sharing rule, that prevail over their propensity to behave opportunistically. We derive two propositions that we test on a dataset of 48 contracts in the French defence procurement. We find that perception of equity turns out to be a key factor in the contractual relationship. This interpretation challenges the prevailing interpretation of a key assumption in transaction cost economics.Comment sont répartis les surcoûts qui résultent de la matérialisation de risques dans le cadre de relations contractuelles ? Nous proposons une réponse qui combine théorie des coûts de transaction et approche en termes d'équité, de manière à expliquer pourquoi des stratégies coopératives de répartition du type 50-50 prévalent sur la propension des partenaires à se comporter de façon opportuniste. Nous en dérivons deux propositions que nous confrontons à une base de données inédite composée de 48 contrats concernant l'approvisionnement de défense en France. Nous montrons que, sous certaines conditions, la perception d'une allocation équitable se révèle un facteur clé de la relation contractuelle, ce qui constitue un défi pour l'interprétation habituelle de la théorie des coûts de transaction