Éditeur(s) : HAL CCSD AGU and the Geochemical Society
Résumé : International audience
The 2004 Aceh and 2005 Nias events are the two greatest earthquakes of the past 40 years with a total rupture of 1700 km long and a coseismic slip reaching up to 25 m. These two earthquakes have caused large stress perturbations which significantly altered seismic activity in the Sumatra-Andaman region. Using both detailed mapping of failure planes and various slip distributions, we calculate this stress change along the Sumatra-Andaman-Sagaing fault system from central Sumatra to southern Myanmar. The static Coulomb stress change Delta CFF and the observed seismic activity are in very good agreement with a Coulomb index similar to 20% greater than the one obtained for random events. Compared to previous studies, this high Coulomb Index confirms two important issues on the use of static stress change criterion: unsuited to study near-field aftershocks and only relevant for aftershocks analysis on large and mature faults at a time scale of several months. The calculated Delta CFF distribution suggests that the 2004 and 2005 earthquakes inhibit failure on the North Andaman rift and on the Sagaing fault, while failure is encouraged along the transform Andaman zone, the central Andaman rift, the West Andaman fault, the Sumatra fault system, and the offshore thrust faults west of Sumatra Island. The maximum value of similar to 15-20 bar (1.5-2 MPa) for Delta CFF is reached in the northern part of the Sumatra fault system. This high value together with the lack of major earthquake in the last 170 years result in a high seismic hazard for this region. Our results are also consistent with temporal evolution of both earthquakes' location and focal mechanism prior to and after the events. In particular, we explain the occurrence and the mechanism of seismic swarms observed in the central Andaman rift and along the west Andaman fault. Finally, our calculations reveal that the seismicity in the Andaman rift zone can only be explained if mu' > 0.5. This result leads to two end-member models: one with a constant and high fault friction and one with spatial variations, for which friction may depend on either the nature of the lithosphere (oceanic versus continental) or the fault type.
ISSN: 1525-2027

hal-00456027
https://hal.archives-ouvertes.fr/hal-00456027
DOI : 10.1029/2008GC002167

Éditeur(s) : HAL CCSD American Chemical Society
Résumé : International audience
The Chromosome-Centric Human Proteome Project (C-HPP) aims at cataloguing the proteins as gene products encoded by the human genome in a chromosome-centric manner. The existence of products of about 82% of the genes has been confirmed at the protein level. However, the number of so-called "missing proteins" remains significant. It was recently suggested that the expression of proteins that have been systematically missed might be restricted to particular organs or cell types, for example, the testis. Testicular function, and spermatogenesis in particular, is conditioned by the successive activation or repression of thousands of genes and proteins including numerous germ cell- and testis-specific products. Both the testis and postmeiotic germ cells are thus promising sites at which to search for missing proteins, and ejaculated spermatozoa are a potential source of proteins whose expression is restricted to the germ cell lineage. A trans-chromosome-based data analysis was performed to catalog missing proteins in total protein extracts from isolated human spermatozoa. We have identified and manually validated peptide matches to 89 missing proteins in human spermatozoa. In addition, we carefully validated three proteins that were scored as uncertain in the latest neXtProt release (09.19.2014). A focus was then given to the 12 missing proteins encoded on chromosomes 2 and 14, some of which may putatively play roles in ciliation and flagellum mechanistics. The expression pattern of C2orf57 and TEX37 was confirmed in the adult testis by immunohistochemistry. On the basis of transcript expression during human spermatogenesis, we further consider the potential for discovering additional missing proteins in the testicular postmeiotic germ cell lineage and in ejaculated spermatozoa. This project was conducted as part of the C-HPP initiatives on chromosomes 14 (France) and 2 (Switzerland). The mass spectrometry proteomics data have been deposited with the ProteomeXchange Consortium under the data set identifier PXD002367
ISSN: 1535-3893

hal-01187320
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01187320
DOI : 10.1021/acs.jproteome.5b00170
PUBMED : 26168773

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Ten to twenty percent of postpartum women experience anxiety or depressive disorders, which can have detrimental effects on the mother, child, and family. Little is known about the neural correlates of these affective disorders when they occur in mothers, but they do have unique neural profiles during the postpartum period compared with when they occur at other times in a woman's life. Given that the neural systems affected by postpartum anxiety and depression overlap and interact with the systems involved in maternal caregiving behaviors, mother–infant interactions are highly susceptible to disruption. Thus, there is an intricate interplay among maternal mental health, the mother–infant relationship, and the neurobiological mechanisms mediating them that needs to be the focus of future study.
ISSN: 0166-2236

hal-01452985
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01452985
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01452985/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01452985/file/The%20Neurobiology%20of%20Postpartum-Tins%20Manscript%20REVISED%20clean%201.pdf
DOI : 10.1016/j.tins.2016.11.009

Éditeur(s) : HAL CCSD
Résumé : International audience
Cytogenetics provides a unique platform to study in situ structural, functional, and evolutionary aspects of the genome. As such it holds powerful promise in decoding mechanisms and processes of genome architectural changes and their role in organism's diversification and evolution. Since the early 80s, such an approach has been applied to the study of the Antarctic notothenioid fishes. In almost three decades, the cytogenetic information has expanded to cover half of the known species inhabiting the high Antarctic waters. Although started 10 years later, cytogenetic studies of species from the Ross sea region have provided valuable contributions to this bulk of knowledge. Here, we synthesize the currently available cytogenetic information on Antarctic notothenioid fishes from the Ross Sea Region, inclusive of both conventional karyotyping and gene mapping. In addition, new karyotypic data on four species (Lepidonotothen squamifrons, Trematomus scotti, T. loennbergii, and T. lepidorhinus) are provided. In discussing these data, specific focus is made on the patterns and subtleties of cytogenetic diversity at inter- and intra-specific levels aiming at contributing to the refinement of the knowledge of fish diversity in a region, the Ross Sea area, whose primary ecological value is widely recognized.
Hydrobiologia

hal-01544905
https://hal.archives-ouvertes.fr/hal-01544905
DOI : 10.1007/s10750-015-2355-5

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Nitro-polycyclic aromatic hydrocarbons (nitro-PAHs) are widespread environmental pollutants, generated from reactions between PAHs and nitrogen oxides during combustion processes. In the present study we have investigated the mechanisms of CXCL8 (IL-8) responses induced by 1-nitropyrene (1-NP) in human bronchial epithelial BEAS-2B cells, with focus on the possible importance of Ca(2+)-signaling and activation of β2-adrenergic receptors (β2AR). Ca(2+)-chelator treatment obliterated 1-NP-induced CXCL8 (IL-8) responses. 1-NP at 10μM (but not 1μM) induced a rapid and sustained increase in intracellular Ca(2+)-levels ([Ca(2+)]i). The early but not the later, sustained phase of 1-NP-induced [Ca(2+)]i was suppressed by beta-blocker treatment (carazolol). Moreover, inhibition of β2AR by blocking-antibody, beta-blocker treatment (ICI 118551) or siRNA transfection attenuated CXCL8 responses induced by 1-NP. The results confirm that PAHs may induce Ca(2+)-signaling also in BEAS-2B cells, at least partly through activation of β2AR, and suggest that both β2AR- and Ca(2+)-signaling may be involved in 1-NP-induced CXCL8 responses in bronchial epithelial cells.
ISSN: 0887-2333

hal-01058607
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01058607
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01058607/document
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01058607/file/Calcium_Signaling_and_I_2-Adrenergic_Receptors-final.pdf
DOI : 10.1016/j.tiv.2014.05.012

Éditeur(s) : HAL CCSD
Résumé : International audience
In real world situations, each person is generally in contact with only a small fraction of the entire population and exchange information through these interactions. Their number and their frequency vary from one to another individual and may be much depending on mobility of individuals. The objective of this article is to better understand how human mobility may have an impact on mobile social networking systems. This should help to answer a question as: "How might an information, a rumor, a pathogen, etc., driven by physical proximity, spread through a population?". We present a first stage of our work in which we focus on percolation processes as information flow mechanisms. We propose a synthetic mobility model and we define an artificial world populated by heterogeneous agents who differ in their mobility. Simulations are conducted on a multi-agent programmable environment. Our experimental results clearly demonstrate positive correlations between agent mobility factors and percolation thresholds.
Procedia CS

hal-00767043
https://hal.archives-ouvertes.fr/hal-00767043
DOI : 10.1016/j.procs.2012.06.007

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The early apoptotic events induced by environmental pollutants with carcinogenic properties are poorly understood. Here, we focus on the early cytotoxic effects of benzo[a]pyrene (B[a]P). In F258 rat hepatic epithelial cells, B[a]P induces intrinsic apoptosis via a mitochondrial dysfunction characterized by the release of hexokinase II (HKII) from the mitochondria. Cancer cells often have an anomalous cell energy metabolism; since HKII dysfunction regulates B[a]P-induced apoptosis in F258 cells, but may also alter cell energy metabolism, HKII release from the mitochondria may represent an important B[a]P-related carcinogenic issue. Thus in the present study, we aimed at deciphering the mechanisms underlying HKII dysfunction upon B[a]P exposure. We show that while glycogen synthase kinase 3 beta (GSK3β) regulated the expression of HKII at the transcriptional level, glycogen synthase kinase 3 alpha (GSK3α) was involved in B[a]P-induced apoptosis via a decrease in c-Myc expression. The reduced level of c-Myc caused the relocation of HKII from the mitochondria to the cytosol, thereby being involved in the formation of reactive oxygen species and apoptosis. In conclusion, we show that the couple GSK3α/c-Myc plays a key role in B[a]P-induced early apoptotic cell signaling via HKII dysfunction.
ISSN: 0887-2333

hal-00682104
https://hal.archives-ouvertes.fr/hal-00682104
https://hal.archives-ouvertes.fr/hal-00682104/document
https://hal.archives-ouvertes.fr/hal-00682104/file/1-s2.0-S0887233311003018-main%20Dendel%C3%A9_%7B75929874-2DF9-47C3-92F6-92AF398668E5%7D.pdf
DOI : 10.1016/j.tiv.2011.11.001

Résumé : L'objectif de cette thèse est de s'intéresser à la chimie des substances naturelles (extraction et caractérisation des molécules issues des forêts de Guyane) et d'étudier des extraits ou familles de molécules naturelles ayant des propriétés inhibitrices de la corrosion du zinc. Dans la première partie du document, un screening de plantes a été effectué. Celles dont les extraits ont présenté les propriétés inhibitrices les plus intéressantes - la Mansoa alliaceae et la Bagassa guianensis -ont été sélectionnées parmi les Il plantes étudiées. Dans la seconde partie du document, différentes techniques électrochimiques ont été utilisées- la spectroscopie d'impédance électrochimique (SEI) et la polarisationlinéaire (PL)- afin de calculer les taux d'inhibition et de remonter aux mécanismes réactionnels caractérisant l'inhibition. Ainsi, le rôle des paramètres tels que le mode d'extraction et le milieu corrosif (ASTM et NaCI3%) sur le taux d'inhibition ont été étudiés. Ces travaux ont débouché sur de nombreux résultats expérimentaux nouveaux et notamment un modèle dynamique prenant en compte l'efficacité de l'inhibiteur en fonction de sa concentration dans le milieu
The objective of this thesis is to focus on the chemistry of na tura! substances (extraction and characterization of molecules from forests of French Guiana) and to study extracts or families ofnatural molecules with inhibiting properties of zinc corrosion. In the first part of the document, a screening of plants was made. Those whose extracts have shown the most interesting potential inhibitors - the Mansoa alliaceae and Bagassa guianensis - were selected among the Il plants studied. In the second part of the paper, different electrochemical techniques were used - the electrochemical impedance spectroscopy (EIS) and linear polarization (LP) - to calculate the inhibition rate and to understand the reaction mechanisms characterizing the inhibition. Thus, the role of parameters such as the method of extraction and the corrosive medium (ASTM and NaCI3%) on the inhibition rate were studied. This work bas led to many new experimental results including a dynamic mode! taking into account the effectiveness of the inhibitor according to its concentration in the medium

http://www.theses.fr/2014AGUY0745/document

Éditeur(s) : HAL CCSD Wiley-Blackwell
Résumé : We use InSAR to measure deformation and kinematics of the Mw = 4.9 Borujerd (2005/05/03) and Mw = 6.1 Chalan-Chulan (2006/03/31) earthquakes that occurred in the Zagros fold-and-thrust belt. The focal mechanism of the 2006 event is consistent with right lateral strike-slip motion and the event ruptured the Dorud-Borujerd segment of the Main Recent Fault. An Envisat interferogram spanning the 2006 event shows peak ground deformation of 9 cm in the satellite line-of-sight along a 10 km long fault portion. The interferogram spanning the 2005 earthquake is rather related to atmospheric artefact than to ground deformation. Dislocation models of the 2006 Chalan-Chulan event indicate dextral slip amounting to a maximum of 90 cm at a depth of 4 km. The predicted vertical displacements are in good agreement with differential levelling data. The 2006 event filled only a small part of the seismic gap located between large M = 7 events that occurred in 1909 and 1957.
ISSN: 0954-4879

hal-00411313
https://hal.archives-ouvertes.fr/hal-00411313
DOI : 10.1111/j.1365-3121.2008.00797.x

Éditeur(s) : HAL CCSD
Résumé : International audience
Earthquake, volcanic eruption, cyclone, flood, tsunami, the Caribbean are particularly vulnerable to many natural hazards. Citizen Education to hazard mitigation is much more important in French West Indies than in Paris. With national, curriculum, evaluation and textbooks, how science education in French West Indies manage the challenge to take account this particularity of our territories? Based on this example and others, the aim of this communication is to present a science education theoretical background focus on contexts studies. During science teaching, learning effects due to different context like social, cultural or language could be described as contextual effects. But others micro-didactic effects of contexts could also be identified as linked with specificity of natural environment. These effects manifest a strain between a goal of teaching or learning and its implementation, when this stain is due in the educational process in different contexts involved.To ensure the quality of education, reference and quantify the effects of educational context seems to be necessary. it should be interested in the process leading to the emergence of these contexts. We propose a simplified model of these processes initially described as meetings of mechanisms operating within a network of transposition of designs. Then we question these processes by degree or forms of contextualization (low to high) and crossed these two approaches, giving an initial typology of contextualisation process. It then emerges the idea that these processes are constrained by resistances. We retain the following three: epistemological, social and educational. As these constraints are expressed in different ways according to disciplines, the data suggest the existence of disciplinary contextualization profiles. All these three approaches (network implementation, degree of contextualization, disciplinary profiles) are three tools for analyzing contextual phenomena which remain to test the robustness and operational character for the training analysis context.
Biennial Conference of Caribbean Academy of Sciences
Barbados, Barbados

hal-01539482
https://hal.univ-antilles.fr/hal-01539482

Éditeur(s) : HAL CCSD MDPI
Résumé : International audience
AbstractThis review provides a global overview of microporous silica based membranes for desalination via pervaporation with a focus on membrane synthesis and processing, transport mechanisms and current state of the art membrane performance. Most importantly, the recent development and novel concepts for improving the hydro-stability and separating performance of silica membranes for desalination are critically examined. Research into silica based membranes for desalination has focussed on three primary methods for improving the hydro-stability. These include incorporating carbon templates into the microporous silica both as surfactants and hybrid organic-inorganic structures and incorporation of metal oxide nanoparticles into the silica matrix. The literature examined identified that only metal oxide silica membranes have demonstrated high salt rejections under a variety of feed concentrations, reasonable fluxes and unaltered performance over long-term operation. As this is an embryonic field of research several target areas for researchers were discussed including further improvement of the membrane materials, but also regarding the necessity of integrating waste or solar heat sources into the final process design to ensure cost competitiveness with conventional reverse osmosis processes. © 2012 by the authors.
ISSN: 2073-4441

hal-01683200
https://hal.univ-antilles.fr/hal-01683200
DOI : 10.3390/w4030629

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We review the evolution of concepts on and methods of estimating the state of stress from fault movements. Theories of failure in isotropic materials suggested a simple geometrical construction of optimal principal stress directions from a fault plane and its associated slip. These optimal directions align shear stress and slip directions and maximize the difference between shear stress and frictional resistance on the fault plane. Optimal stress directions for calcite twinning are obtained by a similar construction, with the difference that they maximize shear stress. Force representation of seismic sources independently introduced pressure, P, and tension, T, axes at positions that also maximize shear stress on both nodal planes. Frictional slip theory and the constraint that slip and shear stress directions be parallel allowed to address reactivation of pre-existing faults. This suggested that stress could also be inverted from reactivated fault and slip data or earthquake focal mechanisms. Early methods relied on geometrical constructions as a substitute for calculations, whereas later methods relied on software as these calculations became tractable with the help of computers. Similar methods were developed for the inversion of stress from crystal twin gliding with non-optimal geometry, with a different criterion that relies on a threshold of the component of shear stress along the gliding line. Even though these methods seek a common stress tensor compatible with fault and slip data, their main use is to separate polyphase data into homogeneous subsets and help deciphering complex tectonic histories. Fault and slip data can also be analyzed to constrain the strain rather than the stress tensor. In most cases this involves a summation and yields an average strain for the considered rock volume. Stress inversion thus appears better suited for differentiating heterogeneous data whereas strain analysis appears better suited for homogenizing them.
ISSN: 0040-1951

hal-00759043
https://hal.archives-ouvertes.fr/hal-00759043
DOI : 10.1016/j.tecto.2012.02.009