Observation of magnetization reversal in epitaxial Gd0.67Ca0.33MnO3 thin films

High quality epitaxial thin films of Gd0.67Ca0.33MnO3 have been deposited onto (100) SrTiO3 substrates by pulsed-laser deposition. Enhanced properties in comparison with bulk samples were observed. The magnetic transition temperature (Tc) of the as-grown films is much higher than the corresponding bulk values. Most interestingly, magnetization measurements performed under small applied fields, exhibit magnetization reversals below Tc, no matter whether the film is field-cooled (FC) or zero-field-cooled (ZFC). A rapid magnetization reversal occurs at 7 K when field cooled, while as for the ZFC process the magnetization decreases gradually with increasing temperatures, taking negative values above 7 K and changing to positive values again, above 83 K. In higher magnetic fields the magnetization does not change sign. The reversal mechanism is discussed in terms of a negative exchange f-d interaction and magnetic anisotropy, this later enhanced by strain effects induced by the lattice mismatch between the film and the substrate.Comment: 16 pages, 4 figure

Millau viaduct geotechnical studies and foundations

AbstractThe Millau viaduct over the Tarn River is an exceptional bridge considering the height under the deck and the 2.5km total length. Each of the seven high piers is founded on a thick raft setting on four large piles of 5m in diameter and 10–15m deep. The ground schematically consists of limestone in the north and of marls in the south. As the bridge is very sensitive to foundation settlements, the concessionary company decided to use the observational method for controlling the displacements and if necessary stabilize the foundations. The measurements show that the movements have remained small and admissible, particularly in terms of the rotations. The settlements have not occurred continuously under the load, but by steps

Does psychological Profile has something to do with satisfaction ? A French retailing Franchisees study

The main purpose of this study is to analyse the relationship between franchisee\u27s personality and franchisee\u27s satisfaction. A sample of 400 French franchisees concerning different sectors is analysed in detail. In the first part of the article, the methodology is presented. Then, theoretical framework concerning satisfaction and personality is developed. Different hypotheses are justified crossing the MSQ scale and the big four model. Conscientiousness seems to be the most predictive factor for satisfaction and results show that the other Big-Five traits are specific in several sectors

Floral vascular patterns of the double-flowered and wild-type morphs of Nigella damascena L. (Ranunculaceae)

The perianth of the double-flowered morph of Nigella damascena L. consists of spirally inserted petaloid sepals and sepal-like organs, similar in shape and colour to the petaloid sepals of the wild-type flower. It is devoid of petals. We compare the vascularization of each organ category of the double flower with that of the wild-type. We show that the vascular patterns of the sepal-like organs and of the petals are identical, and found an inverse relationship between the number of bracts and the number of sepals in the double-flowered morph. These two surprising findings will influence the future evo-devo studies on this plant model

P18-01. Exquisite specificity of CTL response to the M184V mutation

International audiencen.

Specific duplication and dorsoventrally asymmetric expression patterns of Cycloidea-like genes in zygomorphic species of Ranunculaceae.

Floral bilateral symmetry (zygomorphy) has evolved several times independently in angiosperms from radially symmetrical (actinomorphic) ancestral states. Homologs of the Antirrhinum majus Cycloidea gene (Cyc) have been shown to control floral symmetry in diverse groups in core eudicots. In the basal eudicot family Ranunculaceae, there is a single evolutionary transition from actinomorphy to zygomorphy in the stem lineage of the tribe Delphinieae. We characterized Cyc homologs in 18 genera of Ranunculaceae, including the four genera of Delphinieae, in a sampling that represents the floral morphological diversity of this tribe, and reconstructed the evolutionary history of this gene family in Ranunculaceae. Within each of the two RanaCyL (Ranunculaceae Cycloidea-like) lineages previously identified, an additional duplication possibly predating the emergence of the Delphinieae was found, resulting in up to four gene copies in zygomorphic species. Expression analyses indicate that the RanaCyL paralogs are expressed early in floral buds and that the duration of their expression varies between species and paralog class. At most one RanaCyL paralog was expressed during the late stages of floral development in the actinomorphic species studied whereas all paralogs from the zygomorphic species were expressed, composing a species-specific identity code for perianth organs. The contrasted asymmetric patterns of expression observed in the two zygomorphic species is discussed in relation to their distinct perianth architecture

A birational mapping with a strange attractor: Post critical set and covariant curves

We consider some two-dimensional birational transformations. One of them is a birational deformation of the H\'enon map. For some of these birational mappings, the post critical set (i.e. the iterates of the critical set) is infinite and we show that this gives straightforwardly the algebraic covariant curves of the transformation when they exist. These covariant curves are used to build the preserved meromorphic two-form. One may have also an infinite post critical set yielding a covariant curve which is not algebraic (transcendent). For two of the birational mappings considered, the post critical set is not infinite and we claim that there is no algebraic covariant curve and no preserved meromorphic two-form. For these two mappings with non infinite post critical sets, attracting sets occur and we show that they pass the usual tests (Lyapunov exponents and the fractal dimension) for being strange attractors. The strange attractor of one of these two mappings is unbounded.Comment: 26 pages, 11 figure

The STAR Silicon Strip Detector (SSD)

The STAR Silicon Strip Detector (SSD) completes the three layers of the Silicon Vertex Tracker (SVT) to make an inner tracking system located inside the Time Projection Chamber (TPC). This additional fourth layer provides two dimensional hit position and energy loss measurements for charged particles, improving the extrapolation of TPC tracks through SVT hits. To match the high multiplicity of central Au+Au collisions at RHIC the double sided silicon strip technology was chosen which makes the SSD a half million channels detector. Dedicated electronics have been designed for both readout and control. Also a novel technique of bonding, the Tape Automated Bonding (TAB), was used to fullfill the large number of bounds to be done. All aspects of the SSD are shortly described here and test performances of produced detection modules as well as simulated results on hit reconstruction are given.Comment: 11 pages, 8 figures, 1 tabl

Les assemblages de coléoptères saproxyliques des vieux chênes verts en région méditerranéenne : rôle d’une structure-clé dans un paysage hétérogène changeant

A study of spring-summer saproxylic fauna was conducted in a Mediterranean landscape under land use change in order to estimate the relative infl uence of landscape composition vs tree characteristics on beetles’ biodiversity. The composition of the species assemblages and the number of taxa sampled appeared more infl uenced by the characteristics of the sampled Holm oak trees than by the surrounding landscape matrix. The number and the diameter of trunks, the number of cavities and the quantity of visible dead wood were positively correlated either with the total number of taxa or with the observation of specifi c taxa. Mediterranean species did not show an overall preference for open surroundings, and mycetophagous beetles were not particularly selecting woody mesophilous conditions. Our results confi rm the determinant role of old trees as keystone structures for the saproxylic fauna, but, up to now, this role does not seem to be affected by the changes in the landscape that resulted from land abandonment. However, specifi c forest management practices need to be implemented to maintain a population of old Holm oak trees in the absence of the traditional land use practices that favoured themUne étude de la faune saproxylique a été conduite au printemps et en été dans un paysage méditerranéen soumis à des changements d'occupation des terres afin d'estimer l'influence relative de la composition paysagère vs les caractéristiques des arbres sur la biodiversité des coléoptères. La composition des assemblages d'espèces et le nombre de taxons échantillonnés sont apparus plus influencés par les caractéristiques des chênes verts que par la matrice paysagère environnante. Le nombre et le diamètre des troncs, le nombre de cavités et la quantité de bois mort visible étaient positivement corrélés soit avec le nombre total de taxons soit avec l'observation de taxons spécifiques. Les espèces méditerranéennes n'ont pas montré de préférence pour des environnements ouverts et les coléoptères mycétophages ne sélectionnaient pas particulièrement les conditions de boisements mésophiles. Nos résultats confirment le rôle déterminant des vieux arbres en tant que structures-clés pour la faune saproxylique mais jusqu'à présent ce rôle n'apparaît pas affecté par les changements paysagers résultant de l'abandon des terres. Cependant des pratiques spécifiques de gestion forestière demandent à être mises en oeuvre afin de maintenir une population de vieux chênes verts en l'absence des pratiques traditionnelles d'occupation des terres qui les ont favorisés

TAB Bonded SSD Module for the STAR and ALICE Trackers

Presentation made at LEB99, 20-24 September 1999A novel compact detector module has been produced by the "IReS"-"Subatech"-"Thomson-CSF-Detexis" collaboration. It includes a Double-Sided (DS) Silicon Strip Detector (SSD) and the related Front End Electronics (FEE) located on two hybrids, one for the N side and one for the P side. Bumpless Tape Automated Bonding (TAB) is used to connect the detector to the hybrids by means of microcables with neither wirebonding nor pitch adapter. Each of the six dedicated ALICE128C FE chip [1], located on the hybrid, is TABed on identical single layer microcables, which connect its inputs to the DS SSD and its outputs to the hybrid [2]. These microcables are bent in order to fold over the two hybrids on the DS SSD. This module meets the specifications of two experiments, ALICE (A Large Ion Collider Experiment) on the LHC accelerator at CERN [3] and STAR (Solenoid Tracker At Rhic) on the RHIC accelerator at BNL (Brookhaven National Laboratory)[4]. It can be used with air cooling (STAR) as well as with water cooling (ALICE)[5]. This mechanically self-consistent FE module has been tested on the SPS beam at CERN. Preliminary results are presented