Paris West University Nanterre La Défense

About: Paris West University Nanterre La Défense is a education organization based out in Paris, France. It is known for research contribution in the topics: Computer science & Politics. The organization has 895 authors who have published 1430 publications receiving 21712 citations.

Price Clustering in the CAC 40 Index Options Market

Abstract: We examine in details the pattern and systematic tendencies of clustering in CAC 40 index option transaction prices during the period 1997 to 1999. Similar to extant studies in many financial markets, there is evidence of strong clustering at full index points and option prices are 90% more likely to end with the digit 0 (multiples of 10) than with the digit 5. While the 1999 contract downsizing led to some reduction in clustering at full index point, the basic pattern of clustering remains intact. The pattern of clustering rejects the attraction theory, but is consistent with the notion of cost recovery by market makers. We find important drivers for CAC 40 index option price clustering, namely, the level of option premium, option volume and underlying asset volatility. Higher premium level, higher asset volatility and lower volume are seen to increase option price clustering. We also observe a U-shaped pattern of clustering on an intra-day and intra-year basis. The option premium and volatility effects ...

Nonlinear bending of porous curved beams reinforced by functionally graded nanocomposite graphene platelets applying an efficient shear flexible finite element approach

Abstract: In the present study, the nonlinear flexural bending of thick and thin porous curved composite beams reinforced and functionally graded by graphene platelets is carried out using a three-noded C1 continuous curved beam finite element developed introducing an efficient shear deformation theory based on trigonometric function. The nonlinearity through the strain–displacement relationship by introducing von Karman’s assumptions is considered. The nonlinear equilibrium equations resulting from minimum potential energy principle are numerically solved based on the direct iteration technique. The bending nonlinear features through the load–deflection relationship are presented by selecting various design parameters like long and short beams, shallow and deep curved cases, support conditions, the variation of graphene platelets in the metal foam and the existence of porosity. This investigation reveals that the level of nonlinearity gets noticeably affected by the depth coupled with the curved beam slenderness ratio.

Contracting with Governments

Abstract: In this paper we review contracting issues raised by a government’s decision to contract out activities linked to public services, as well as highlighting potential future research avenues. We first review the different kinds of contracting arrangements and public private partnerships used by government to contract out their activities. In Section 1, we highlight the difficulties linked to the specificities of the arrangements between the government, considered a competent and benevolent dictator, due to complex information and commitment issues. We focus on the different sources of contractual failures resulting from contractual incompleteness and from imperfect competition among the potential private providers of public services. We then focus on the specificities of the relationship between the private and public parties that might be non-benevolent and therefore submitted to specific constraints to control potential disfunctioning like corruption, (see Section 2). Lastly we consider the “government” no longer as an homogeneous entity, but as a complex, multi-purpose organization submitting third parties to specific hazards (Section 3). Suggestions for further research follow in the conclusion.

Anciennes et nouvelles hypothèses d’interprétation du gravettien moyen en France : la question de la place des industries à burins du Raysse au sein de la mosaïque gravettienne

Abstract: Si le Gravettien est souvent considere comme une des premieres cultures pan-europeennes attribuees a l’homme moderne, il est neanmoins entendu que des particularites regionales ont du exister sur une aussi longue plage de temps et un aussi vaste territoire. Ces moments particuliers n’ont toutefois que rarement ete mis en evidence a ce jour. En France, de recents travaux sur le Gravettien moyen (ex-Perigordien Vc de Peyrony) permettent aujourd’hui de relancer les reflexions dans ce domaine (Klaric 2003 ; Pottier 2005). Dans le Sud-Ouest de la France, le Gravettien moyen est divise en deux phases (d’apres la stratigraphie de l’Abri Pataud) : la premiere est caracterisee par l’abondance des burins de Noailles et la seconde par la dominance des burins du Raysse (David 1995). Les industries du Gravettien moyen paraissent presenter une forte polymorphie due a l’alternance des burins de Noailles et du Raysse et a des quantites tres variables d’armatures a dos abrupt (gravette, microgravette et lamelle a dos). Dans la seconde moitie du XXe siecle, cette forte polymorphie conduisit plusieurs auteurs a proposer diverses interpretations culturelles des industries rattachees a cette phase. Jusqu’a maintenant, deux hypotheses ont domine les discussions, mais aucun argument decisif n’a pu etre apporte en faveur de l’une ou de l’autre. La premiere est fondee sur la sequence de l’Abri Pataud et considere que les phases « noaillienne » et « rayssienne » constituent deux etapes successives d’un facies culturel (« le Noaillien ») distinct du reste du Perigordien (David 1995 in : Bricker (dir.) 1995 p. 130). La seconde hypothese propose que les differences entre les industries refletent une variabilite fonctionnelle. Les fluctuations des quantites de burins de Noailles, du Raysse et des pointes a dos abrupt sont alors interpretees comme le resultat d’activites particulieres conduisant a la proliferation de tel ou tel type d’outils (Laville et Rigaud 1973 ; Rigaud 1982). Des recherches recentes (Klaric 2003) et les decouvertes realisees sur un nouveau site rayssien (La Picardie, Indre-et-Loire) semblent finalement contredire cette seconde hypothese et relancer les discussions a propos de la premiere. Ces travaux conduisent egalement a proposer un nouveau scenario interpretatif de la phase rayssienne, cette derniere etant alors consideree comme une sorte d’episode paleohistorique ou les traditionnelles pointes de La Gravette sont absentes (ou quasiment).