Liquid-gas phase transition in hot nuclei studied with INDRA

Thanks to the high detection quality of the INDRA array, signatures related to the dynamics (spinodal decomposition) and thermodynamics (negative microcanonical heat capacity) of a liquid-gas phase transition have been simultaneously studied in multifragmentation events in the Fermi energy domain. The correlation between both types of signals strongly supports the existence of a first order phase transition for hot nuclei.Comment: 9 pages, 2 figures, Invited talk to Nucleus-nucleus 2003 Moscow June 200

Expression of the SST receptor 2 in uveal melanoma is not a prognostic marker

Introduction Uveal melanoma (UM) cells and neurohormone-producing cells both originate from the neural crest. Somatostatin receptors subtype 2 (SSTR2) are over-expressed in several tumors, often from neuroendocrine origin, and synthetic antagonists like octreotide and octreotate are being used as diagnostic or therapeutic agents. We investigated the SSTR2 expression in UM, and determined whether this expression was related to prognosis of the disease. Materials and methods UM cell lines and fresh primary UM samples were tested for SSTR2 expression by autoradiography (AR) using 125I-Tyr3-octreotate. Furthermore, UM cell lines were analyzed for SSTR2 mRNA expression with quantitative real-time RT-PCR. Results Using AR, cell-surface SSTR2 expression was demonstrated in two UM metastatic cell lines, but no expression was detected in three cell lines derived from primary UM. However, all primary and metastatic UM cell lines showed mRNA expression levels for SSTR2 using quantitative real-time RT-PCR. Only three of 14 primary UM demonstrated moderate SSTR2 expression, and this expression was not significantly associated with tumor-free survival or any tested prognostic factor. Conclusions Based on the rare and low expression of SSTR2 found in primary UM specimens and in UM cell lines, we conclude that SSTR2 is not widely expressed in UM. Furthermore, SSTR2 expression was not associated with tumor-free survival and prognostic factors. Therefore SSTR2 is not suited as prognostic marker or therapeutic target in UM

Creating personalized assessments based on learner knowledge and objectives in a hypermedia Web testing application

This paper presents an adaptive Web testing system where the adaptation of the testing procedure relies on the performance, the prior knowledge and the goals and preferences of the test participants. The main aim of the paper is to discuss the utility of the adaptive assessment tool. Therefore, the paper presents the authoring process of a number of adaptive assessments, where the educators utilized different adaptive rules to create summative and formative assessments. The paper presents the employed adaptive rules and summarizes the key points of the pilot study.</p

Episodic slab rollback fosters exhumation of HP-UHP rocks

International audienceThe burial-exhumation cycle of crustal material in subduction zones can either be driven by the buoyancy of the material, by the surrounding flow, or by both. High pressure and ultrahigh pressure rocks are chiefly exhumed where subduction zones display transient behaviours, which lead to contrasted flow regimes in the subduction mantle wedge. Subduction zones with stationary trenches (mode I) favour the burial of rock units, whereas slab rollback (mode II) moderately induces an upward flow that contributes to the exhumation, a regime that is reinforced when slab dip decreases (mode III). Episodic regimes of subduction that involve different lithospheric units successively activate all three modes and thus greatly favour the exhumation of rock units from mantle depth to the surface without need for fast and sustained erosion