[1] On-axis deep tow side scan sonar data are used together with off-axis bathymetric data to investigate the temporal variations of the accretion processes at the ultra-slow spreading Southwest Indian Ridge. Differences in the length and height of the axial volcanic ridges and various degrees of deformation of these volcanic constructions are observed in side scan sonar images of the ridge segments. We interpret these differences as stages in an evolutionary life cycle of axial volcanic ridge development, including periods of volcanic construction and periods of tectonic dismemberment. Using off-axis bathymetric data, we identify numerous abyssal hills with a homogeneous size for each segment. These abyssal hills all display an asymmetric shape, with a steep faulted scarp facing toward the axis and a gentle dipping volcanic slope facing away. We suggest that these hills are remnants of old split axial volcanic ridges that have been transported onto the flanks and that they result from successive periods of magmatic construction and tectonic dismemberment, i.e., a magmato-tectonic cycle. We observe that large abyssal hills are in ridge sections of thicker crust, whereas smaller abyssal hills are in ridge sections of thinner crust. This suggests that the magma supply controls the size of abyssal hills. The abyssal hills in ridge sections of thinner crust are regularly spaced, indicating that the magmato-tectonic cycle is a pseudoperiodic process that lasts $0.4 m.y., about 4 to 6 times shorter than in ridge sections of thicker crust. We suggest that the regularity of the abyssal hills pattern is related to the persistence of a nearly constant magma supply beneath long-lived segments. By contrast, when magma supply strongly decreases and becomes highly discontinuous, regular abyssal hills patterns are no longer observed.

Classical techniques based on bone imaging allow visual examination or provide quantitative parameters like bone mineral density, which is a mass per unit of surface. Unfortunately, these techniques are generally expensive. A new method of bone characterization that uses ultrasound techniques is presented in this article. This method is able to evaluate mechanical properties like Young's modulus E and cortical bone thickness with low-frequency transducers and does not require the use of a coupling medium. Some results of Young's modulus measurements are presented and compared to the literature values and the pulse echo method.

Abstract. Forensic entomology can help to estimate the time elapsed since death, by studying the necrophagous species collected on a cadaver and its surroundings. The determination of the socalled post mortem interval (PMI or period of fi rst oviposition) is based on the development time of necrophagous dipterans and on the chronological pattern of insects' succession on the corpse throughout the decaying process. In the present study, authors investigated this succession by the analysis of the database of the Department of Forensic Entomology of the French Gendarmerie over 12 years (1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003) in order to propose a new approach and a new hypothsesis of the dynamic of necrophagous insects' populations present on a human cadaver over time. For all treated cases, the presence/absence and the oldest development stage of the species were recorded. Data were analyzed by statistical and Wagner parsimony methods. The statistic results allowed the association of groups of species with typical developmental stages. The Wagner parsimony analysis showed that the dynamic of the necrophagous insect population present on a cadaver could be characterised by specifi c species. Together, they allowed establishing hypotheses of succession of necrophagous insects on human cadavers over time that could be usefull in the PMI estimation.Résumé. Entomologie forensique : une nouvelle hypothèse de succession chronologique d'insectes nécrophages sur les cadavres humains. L'entomologie légale permet d'estimer le temps écoulé depuis la mort grâce à l'étude des insectes nécrophages collectés sur un cadavre et dans son environnement. La détermination du délai post-mortem (Post Mortem Interval ou PMI) ou de la période de première oviposition (ponte) est basée sur l'étude des temps de développement des Diptères nécrophages et de la succession des insectes sur le corps en fonction des états de décomposition. Dans cette étude, nous analysons la succession des insectes nécrophages provenant de la base de données du Département d'Entomologie de l'Institut de Recherche Criminelle de la Gendarmerie Nationale (IRCGN) au travers de 12 années d'activité (1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003). Le but de cette étude est de proposer une nouvelle approche et une nouvelle hypothèse de la dynamique des populations d'insectes nécrophages présents sur un cadavre au cours du temps. La présence/absence et le stade de développement le plus ancien par espèce sont recensés. Les données sont analysées statistiquement et par la méthode de la parcimonie de Wagner. L'analyse statistique met en évidence des associations d'espèces en fonction de stades types de développement. La parcimonie de Wagner montre que la dynamique des populations d'insectes nécrophages présents sur un cadavre, peut être caractérisée par la présence de certaines espèces. Elle permet également d'établir des hypothèses sur la succession des insectes sur les cadavres humains au cours du temps, pouvant être...

Localizing two or more components of assemblies in biological systems requires both continued development of fluorescence techniques and invention of entirely new techniques. Candidates for the latter include dynamic secondary ion mass spectrometry (D-SIMS). The latest generation of D-SIMS, the Cameca NanoSIMS 50, permits the localization of specific, isotopically labeled molecules and macromolecules in sections of biological material with a resolution in the tens of nanometers and with a sensitivity approaching in principle that of a single protein. Here we use two different systems, crystals of glycine and mixtures of proteins, to show that the formation of recombinant CN secondary ions under Cs bombardment can be exploited to create a new colocalization technique. We show experimentally that the formation of the recombinant (13)C(15)N secondary ion between (13)C- and (15)N-labeled macromolecules is indeed an indicator of the distance between the interacting macromolecules and on their shape. We build up a convolution model of the mixing-recombination process in D-SIMS that allows quantitative interpretations of the distance-dependent formation of the recombinant CN. Our results show that macromolecules can be colocalized if they are within 2 nm of one another. We discuss the potential advantages of this new technique for biological applications.

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