Rhapsodes et poètes épiques à l'époque impériale

Ce travail concerne les rhapsodes et poètes épiques de l'époque impériale, étudiés à partir de la prosopographie des technites dionysiaques qui a été établie par I. E. Stephanis. Ces artistes étaient très appréciés à l'époque hellénistique ; l'objectif est d'examiner dans quelle mesure ils restent un vecteur de diffusion des mythes homériques, quels sont les contextes de leurs prestations et quelles sont leurs fonctions comme représentants de la poésie épique traditionnelle à l'époque impériale. La première partie discute certaines identifications de Stephanis et analyse les rapports entre rhapsodes et homéristes, pour donner une estimation du nombre des rhapsodes et des poètes épiques dont on a gardé la trace. La seconde partie étudie leur répartition dans l'espace et dans le temps, entre la fin du Ier siècle avant J.-C. et la deuxième moitié du IIIe siècle après J.-C., afin de dégager leurs fonctions culturelles et sociales et d'interpréter la diminution considérable de leur nombre dans les concours, auditions ou fêtes privées.

Geochemical changes at the Permian-Triassic transition in Southern Alps and adjacent area: a review

Compilation of the recent literature from the Southern Alps and adjacent area confirms the geochemical variations of unusual amplitudes during the Permian-Triassic boundary interval (PTBI). A great attention has been given to the negative δ13C anomaly within the Tesero Member close to the Permian-Triassic boundary. Very detailed geochemical works have been done on the scientific Gartnerkofel core (Gk-1) and on the Slovenian sections. Major minor and rare earth elements (REE) data are reported and show a marked enrichment in alkaline metals and REE of some levels of the boundary interval. But recent studies show that the low Iridium anomalies and the Osmium and Helium isotopes anomalies lack the characteristics of a large extraterrestrial impact.

Impedance field and transition from thermal to shot noise in Cd1-xZnxTe semi-insulating Ohmic detectors

Within a drift-diffusion model we investigate the role of the self-consistent electric field in determining the impedance field of a macroscopic Ohmic (linear) resistor made by a compensated semi-insulating semiconductor at arbitrary values of the applied voltage. The presence of long-range Coulomb correlations is found to be responsible for a reshaping of the spatial profile of the impedance field. This reshaping gives a null contribution to the macroscopic impedance but modifies essentially the transition from thermal to shot noise of a macroscopic linear resistor. Theoretical calculations explain a set of noise experiments carried out in semi-insulating CdZnTe detectors.

Effects of Nb doping on the TiO2 anatase-to-rutile phase transition

We study the influence of Nb doping on the TiO2 anatase-to-rutile phase transition, using combined transmission electron microscopy, Raman spectroscopy, x-ray diffraction and selected area electron diffraction analysis. This approach enabled anatase-to-rutile phase transition hindering to be clearly observed for low Nb-doped TiO2 samples. Moreover, there was clear grain growth inhibition in the samples containing Nb. The use of high resolution transmission electron microscopy with our samples provides an innovative perspective compared with previous research on this issue. Our analysis shows that niobium is segregated from the anatase structure before and during the phase transformation, leading to the formation of NbO nanoclusters on the surface of the TiO2 rutile nanoparticles.

Rebuild Iowa Office Transition Strategy

The Rebuild Iowa Transition Strategy has been drafted to provide a comprehensive set of recommended action steps to help the state complete long-term recovery efforts while better preparing the state for future disasters. This report begins with a review of the 12 major Rebuild Iowa Advisory Commission (RIAC) recommendations which have guided RIO’s work, followed by a summary of the major accomplishments toward each recommendation. The identification of remaining needs and issues serves as the basis for the transition strategy. The following outlines the action steps necessary to achieve a successful transition and recovery.

Avalanches in a fluctuationless first-order phase transition in a random-bond Ising model

We study the behavior of the random-bond Ising model at zero temperature by numerical simulations for a variable amount of disorder. The model is an example of systems exhibiting a fluctuationless first-order phase transition similar to some field-induced phase transitions in ferromagnetic systems and the martensitic phase transition appearing in a number of metallic alloys. We focus on the study of the hysteresis cycles appearing when the external field is swept from positive to negative values. By using a finite-size scaling hypothesis, we analyze the disorder-induced phase transition between the phase exhibiting a discontinuity in the hysteresis cycle and the phase with the continuous hysteresis cycle. Critical exponents characterizing the transition are obtained. We also analyze the size and duration distributions of the magnetization jumps (avalanches).

Vibrational behaviour of bcc Cu-based shape memory alloys close to the martensitic transition

Experimental data from ultrasonic and inelastic neutron scattering measurements are analyzed for different families of Cu-based shape-memory alloys. It is shown that the transition occurs at a value, independent of composition and alloy family, of the ratio between the elastic constants associated with the two shears necessary to accomplish the lattice distortion from the bcc to the close-packed structure. The zone boundary frequency of the TA2[110] branch evaluated at the transition point (TM), weakly depends, for each family, on composition. A linear relationship between this frequency and the inverse of the elastic constant C', both quantities evaluated at TM, has been found, in agreement with the prediction of a Landau model proposed for martensitic transformations.