Éditeur(s) : HAL CCSD
Résumé : In Taiwan , the subduction of the Chinese continental margin under the Luzon arc results in the progressive growth of an active orogenic wedge. It is one of the best places to study the complex relationships that occurs between the tectonic processes controlling deformation (plate rheology and kinematics, metamorphism and magmatism) and surface processes (erosion and sedimentation). In order to study the kinematics of the present day convergence of Philippine Sea plate to the Asian continent around Taiwan, we perform 2D and 3D sandbox modeling and we analyzed the models with PIV (Particle Image Velocimetry) software. In 2D experiments, a model Coulomb wedge is submitted to erosion and sedimentation under topography and flux steady state conditions. The 3D experiments are mainly used to study the escape tectonics occurring in the middle west and southwest Taiwan. A wedge shaped indenter and a basement relief were used to simulate the mechanical plate boundary between Philippine Sea plate and Eurasia plate and the basement topography to the west of Taiwan respectively. We examine the exhumation patterns, the mode of fault propagation and displacement patterns by strain partitioning of vertical vs. horizontal displacement and convergent parallel vs. orogen parallel components. The preliminary conclusions are: 1. The interactions between tectonics, erosion and sedimentation control geometry and kinematics of the doubly vergent transpressional orogen. 2. Exhumation processes are controlled by the balance between erosion, frontal accretion and underplating in different structural domains of the wedge. 3. Retrowedge erosion favorites backfolding and backthrusting, induces flower structures and fan shaped cleavage distribution. 4. Sedimentation promotes underplating and out-of sequences thrusting. 5. Continental subduction or subduction of topographic highs will enhance underthrusting/underplating, thick-skin tectonics and inversion of sedimentary basin.
Bolletino di Geofisica teorica ed applicata

hal-00411133
https://hal.archives-ouvertes.fr/hal-00411133

Éditeur(s) : HAL CCSD Landes Bioscience
Résumé : International audience
In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
Autophagy

hal-00735751
https://hal.archives-ouvertes.fr/hal-00735751
PUBMED : 22966490

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
In order to better constrain the relationship between tectonics and sedimentation of the Eastern Sardinian Margin, from the Messinian to the present day (METYSS project), a lithostratigraphic study was carried out on the Late Neogene deposits along the Cedrino Valley (eastern Sardinia). The late Neogene evolution is documented from sedimentological and tectonic analysis, biostratigraphic dating, and by mapping and logging stratigraphic sections. Previous authors have differentiated an early Pliocene marine formation from an older continental formation, possibly Miocene, the entire system being covered by late Pliocene to Quaternary lava flows. Preliminary biostratigraphic data suggest the absence of the lowermost Pliocene, based on the absence of Globorotalia margaritae and the presence of Globorotalia puncticulata, implying a sediment age between 3.81 and 2.41 Ma. At the foot of the Fiuli cliff, some mud clasts include a coccolith microflora, Tortonian in age, suggesting reworking. The Pliocene marine deposits consist of a single filling sequence instead of a succession of superimposed sequences as we would expect during this period of time; the occurrences of terms rarely respect the usual transgressive-regressive succession. Contrasting bathymetric environments (fore-shore, pro-delta, shelf or upper slope) can be abruptly superimposed on top of the other, along few meter thick intervals. A rapidly flooded term is observed in several sites and indicates a spatial variability over only a few kilometers distance. Some deep water deposits are in the middle of the infilling Pliocene sequence, whereas shallower water deposits can be repeated along a vertical section, or even interrupted by emersion. These marked differences can express syn-, or possibly post-sedimentation tectonic uplifts. The 10–25° bed dips originated through local tectonic uplift. At Fiuli, the geometry of the bedding planes is indicative of tilting toward the west, in a direction opposite to the one observed at Onifai. These Pliocene series form a wide syncline with an approximately NNE–SSW axis. This morpho-structural behavior appears to be largely atypical of this East-Sardinian coastal area.
ISSN: 1040-6182

hal-01134707
https://hal.archives-ouvertes.fr/hal-01134707
DOI : 10.1016/j.quaint.2014.11.022