Éditeur(s) : HAL CCSD Cambridge University Press (CUP)
Résumé : International audience
Upper Triassic volcanic and sedimentary rocks of the Mamonia Complex in southwestern Cyprus are exposed in erosional windows through the post-Cretaceous cover, where the Mamonia Complex is tectonically imbricated with the Troodos and Akamas ophiolitic suites. Most of these Upper Triassic volcanic rocks have been considered to represent remnants of Triassic oceanic crust and its associated seamounts. New Nd and Pb isotopic data show that the whole Mamonia volcanic suite exhibits features of oceanic island basalts (OIB). Four rock types have been distinguished on the basis of the petrology and chemistry of the rocks. Volcanism began with the eruption of depleted olivine tholeiites (Type 1) and oceanic island tholeiites (Type 2) associated with deep basin siliceous and/or calcareous sediments. The tholeiites were followed by highly phyric alkali basalts (Type 3) interbedded with pelagic Halobia-bearing limestones or white reefal limestones. Strongly LREE-enriched trachytes (Type 4) were emplaced during the final stage of volcanic activity. Nd and Pb isotopic ratios suggest that tholeiites and mildly alkali basalts derived from partial melting of heterogeneous enriched mantle sources. Fractional crystallization alone cannot account for the derivation of trachytes from alkaline basalts. The trachytes could have been derived from the partial melting at depth of mafic material which shares with the alkali basalts similar trace element and isotopic compositions. This is corroborated by the rather similar isotopic compositions of the alkali basalts and trachytes. The correlations observed between incompatible elements (Nb, Th) and {varepsilon}Nd and Pb isotopic initial ratios suggest that the Mamonia suite was derived from the mixing of a depleted mantle (DMM) and an enriched component of High µ (µ = 238U/204Pb, HIMU) type. Models using both Nd and Pb isotopic initial ratios suggest that the depleted tholeiites (Type 1) derived from a DMM source contaminated by an Enriched Mantle Type 2 component (EM2), and that the oceanic tholeiites (Type 2), alkali basalts (Type 3) and trachytes (Type 4) were derived from the mixing of the enriched mantle source of the depleted tholeiites with a HIMU component. None of the Mamonia volcanic rocks show evidence of crustal contamination. The Upper Triassic within-plate volcanism likely erupted in a small southerly Neotethyan basin, located north of the Eratosthenes seamount and likely floored by oceanic crust.
ISSN: 0016-7568

insu-00353657
https://hal-insu.archives-ouvertes.fr/insu-00353657
DOI : 10.1017/S0016756806002937

Éditeur(s) : HAL CCSD Société géologique de France
Résumé : New radiolarian assemblages of Late Jurassic age were extracted from seven chert localities of the basement comp ex of La Desirade Island (Guadeloupe), the oldest geological unit of the Lesser Antilles arc and the eastern Caribbean region. These fauna range in age from Kimmeridgian or early Tithonian to early or early late Tithonian, showing that La Desirade cherts are not all coeval, contrary to what was established by previous studies. Furthermore, the close spatial association of cherts and volcanic elements composed of basaltic flows and volcaniclastics suggests a mixed setting of hydrothermal siliceous deposits and biogenous sedimentation consistent with an arc-related oceanic setting rather than an ophiolite-type oceanic crust. As the Youngest age is obtained to the northwest of the basement complex where as older data are found to the southeast, it also Suggests that La Desirade basement complex may have undergone some structural stacking consistent with an accretion-type geodynamic getting. Our biochronological data provide a preliminury try tectonic model of an eastward subduction zone for Lesser Antilles arc basement emplacement during the Mesozois.
EISSN: 1777-5817

hal-00445252
https://hal.archives-ouvertes.fr/hal-00445252
DOI : 10.2113/gssgfbull.180.5.399

Éditeur(s) : HAL CCSD
Résumé : International audience
In this work, an alkaloids extract from Annona squamosa plant have been studied as possible corrosion inhibitor for C38 steel in molar hydrochloric acid (1 M HCl). Potentiodynamic polarization and AC impedance methods have been used. The corrosion inhibition efficiency increases on increasing plant extract concentration. Polarisation studies showed that Annona squamosa extract was mixed-type inhibitor in 1 M HCl. The inhibition efficiency of Annona squamosa extract was temperaturedependent and its addition led to an increase of the activation corrosion energy revealing a physical adsorption between the extract and the metal surface. The adsorption of the Annona squamosa extractfollowed Langmuir’s adsorption isotherm. The inhibitive effect of Annona squamosa is ascribed to the presence of organic compounds in the extract. The examined extract is considered as non-cytotoxic substance.
International journal of electrochemical science

hal-01094042
https://hal-agroparistech.archives-ouvertes.fr/hal-01094042

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Because many biological processes related to the dynamics of infectious diseases are caused by complex interactions between the environment, the host(s) and the agent(s), the necessity to address the methodological implications of this inherent complexity has recently emerged in epidemiology. Most epidemiologists now acknowledge that most human infectious diseases are likely to have complex dynamics. However, this knowledge still percolates with difficulty in their statistical "modus operandi". Indeed, for the study of complex systems, the traditional first-line statistical toolbox of epidemiologists (mainly built around the Generalized Linear Model family), despite its undeniable practicality and robustness, has structural limitations deprecating its usefulness. Three major sources of complexity neglected or not taken into account by this first-line statistical toolbox and having deep statistical implications are the multi-level organization of data, the non-linear relationships between variables and the complex interactions between variables. Three promising candidates to incorporate along with traditional tools for a new first-line statistical toolbox more suitable to apprehend these sources of complexity are the generalized linear mixed models, the generalized additive models, and the structural equation models. The aforementioned methodologies have the advantage to be generalizations of GLM models and are relatively easy to implement. Their assimilation and implementation would thus be greatly facilitated for epidemiologists. More globally, this text underlines that an improved use of other methods as such described here compared to traditional ones has to be performed to better understand the complexity challenging epidemiologists every day. This is particularly true in the field of infectious diseases for which major public health challenges will have to be addressed in the coming decades.
ISSN: 1567-1348

inserm-00872354
http://www.hal.inserm.fr/inserm-00872354
http://www.hal.inserm.fr/inserm-00872354/document
http://www.hal.inserm.fr/inserm-00872354/file/main_document.pdf
DOI : 10.1016/j.meegid.2013.09.006

Éditeur(s) : NRC
Résumé : We studied relationships between tropical tunas (albacore (Thunnus alalunga), bigeye (Thunnus obesus), and yellowfin (Thunnus albacares)) and their biotic and abiotic environments through simultaneous acoustic observations of tunas and their prey, experimental longline catch, and oceanographic data in French Polynesia. Vertical habitat limits were estimated based on temperature and dissolved oxygen at capture data. We then studied tuna-micronekton relationships to better understand how tuna occupy the pelagic space, At a regional scale, tunas were more abundant in areas rich in prey with favourable hydrological conditions. Inside such areas, at the scale of a longline set, however, the longline catches were maximal only when prey were not distributed in dense patches (except for yellowfin tuna). We interpreted this result by considering that areas with high prey abundance attract tunas, but at a small scale, if prey are patchy distributed, tunas are more inclined to feed on them rather than on longline baits. The effect of patches on yellowfin tuna catch per unit effort (CPUE) does not appear likely because this species also feeds on the mixed layer, where patch density was very low. Not only hydrological characteristics, but also prey density and prey patch characteristics, should be taken into account for interpreting longline CPUE data.
Thunnus obesus, et thon à nageoires jaunes, Thunnus albacares) à leurs environnements biotique et abiotique. Pour ce faire, nous avons réalisé simultanément, en Polynésie Française, des observations acoustiques des thons et de leurs proies, des pêches à l'aide d'une palangre instrumentée et des mesures hydrologiques. Des limites d'habitat vertical des thons calculées sur la base de données de température et d'oxygène dissous sont proposées. Nous étudions ensuite les relations thons-micronecton afin de mieux comprendre la stratégie d'occupation de l'espace des thons. A une échelle régionale, les thons sont plus abondants dans des zones riches en proies avec des conditions hydrologiques favorables. Cependant, à l'intérieur de telles zones, les captures sont maximales lorsque les proies ne sont pas distribuées sous forme de patchs (sauf pour le thon à nageoires jaunes). Nous interprétons ces résultats en considérant que les zones de fortes abondances en proies attirent les thons mais, qu'à une échelle fine, si les proies sont distribuées sous la forme de patchs denses, les thons s'en nourrissent préférentiellement, au détriment des appâts de la palangre. Ces patchs ne semblent pas influencer les prises par unité d'effort (PUE) des thons à nageoires jaunes, probablement parce que cette espèce se nourrit également dans la couche homogène où la densité en patchs est très faible. Les caractéristiques hydrologiques, mais également la densité en proies et leur type de distribution, devraient donc être pris en compte pour l'interprétation des données de PUE.
Canadian journal of fisheries and aquatic sciences (0706-652X) (NRC), 2002-06 , Vol. 59 , N. 6 , P. 1002-1013

Droits : 2002 NRC Canada
http://archimer.ifremer.fr/doc/2002/publication-733.pdf
DOI:10.1139/F02-073
http://archimer.ifremer.fr/doc/00000/733/

Éditeur(s) : HAL CCSD BioMed Central
Résumé : International audience
Background: The Ras/Raf/MEK/ERK signaling pathway is involved in essential cell processes and it is abnormally activated in similar to 30 % of cancers and cognitive disorders. Two ERK isoforms have been described, ERK1 and ERK2; ERK2 being regarded by many as essential due to the embryonic lethality of ERK2 knock-out mice, whereas mice lacking ERK1 are viable and fertile. The controversial question of why we have two ERKs and whether they have differential functions or display functional redundancy has not yet been resolved. Results: To investigate this question we used a novel approach based on comparing the evolution of ERK isoforms' sequences and protein expression across vertebrates. We gathered and cloned erk1 and erk2 coding sequences and we examined protein expression of isoforms in brain extracts in all major clades of vertebrate evolution. For the first time, we measured each isoforms' relative protein level in phylogenetically distant animals using anti-phospho antibodies targeting active ERKs. We demonstrate that squamates (lizards, snakes and geckos), despite having both genes, do not express ERK2 protein whereas other tetrapods either do not express ERK1 protein or have lost the erk1 gene. To demonstrate the unexpected squamates' lack of ERK2 expression, we targeted each ERK isoform in lizard primary fibroblasts by specific siRNA-mediated knockdown. We also found that undetectable expression of ERK2 in lizard is compensated by a greater strength of lizard's erk1 promoter. Finally, phylogenetic analysis revealed that ERK1 amino acids sequences evolve faster than ERK2' s likely due to genomic factors, including a large difference in gene size, rather than from functional differences since amino acids essential for function are kept invariant. Conclusions: ERK isoforms appeared by a single gene duplication at the onset of vertebrate evolution at least 400 Mya. Our results demonstrate that tetrapods can live by expressing either one or both ERK isoforms, supporting the notion that ERK1/2 act interchangeably. Substrate recognition sites and catalytic cleft are nearly invariant in all vertebrate ERKs further suggesting functional redundancy. We suggest that future ERK research should shift towards understanding the role and regulation of total ERK quantity, especially in light of newly described erk2 gene amplification identified in tumors.
ISSN: 1471-2148

hal-01546165
https://hal.archives-ouvertes.fr/hal-01546165
DOI : 10.1186/s12862-015-0450-x

Éditeur(s) : Instituto de Investigaciones Agronómicas, Facultad de Agronomía, USAC Instituto de Investigaciones Agronómicas, Facultad de Agronomía, USAC ( Guatemala )
Résumé : (Bibliography) Includes bibliographical references.
(Statement of Responsibility) Instituto de Investigaciones Agronómicas, Facultad de Agronomía, USAC ; Instituto Nacional de Administración Pública ; Instituto Interamericano de Cooperación para la Agricultura.
"Octubre/86."
(Funding) Electronic resources created as part of a prototype UF Institutional Repository and Faculty Papers project by the University of Florida.
Guatemala
Guatemala

71121724

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Development of hepatocellular carcinoma (HCC) is a complex and progressive disease that involves cycles of liver cell death, inflammation, and tissue regeneration/remodelling. Chemokines and chemokine receptors play numerous and integral roles in the disease progression of HCC. Here we investigated the novel chemokine receptor CXCR7/RDC1 in HCC progression, its two known ligands CXCL12 and CXCL11, as well as the other CXCL12 receptor, CXCR4. Our results show that in a cohort of 408 human HCCs, CXCR7 and CXCL11 were significantly higher in tumours compared to normal liver controls (5- and 10-fold, respectively). Immunohistochemical (IHC) staining on human HCC sections confirmed that both CXCL11 and CXCR7 were much higher in cancer tissues. Furthermore, IHC staining revealed that CXCR7 protein was only expressed in endothelial cells whereas CXCL11 exhibited a much broader tissue expression. At the cellular level we observed that in vitro, human microvascular endothelial cells (HMEC-1) up-regulated CXCR7 under hypoxic and acidic pH conditions, which are well known characteristics of the HCC tumour micro-environment. As for its ligand, we observed that IFNγ robustly induced CXCL11 in hepatic stellate cells, hepatocytes, and HMEC-1s. In addition, in the mouse Diethylnitrosamine model of hepatocarcinogenesis we observed a very strong induction of CXCR7 and CXCL11 transcripts, confirming that CXCR7/CXCL11 up-regulation is conserved between human and mice liver cancer. Altogether, our results strongly support the hypothesis that the CXCL11/CXCR7 pathway is involved HCC progression.
ISSN: 0959-8049

hal-00682463
https://hal.archives-ouvertes.fr/hal-00682463
DOI : 10.1016/j.ejca.2011.06.044
PUBMED : 21778049

Éditeur(s) : HAL CCSD Springer/Terra Scientific Publishing Company
Résumé : International audience
This study of the Cajati deposit provides evidence that the ore was neither purely hydrothermal, nor volcanic in origin, as previous workers have proposed. The ores were formed from magnetite-rich magmas, hydrothermally altered and intruded at an indicated crustal depth in excess of 500 m. The mineralogical and textural association between magnetite and magnesioferrite in the carbonatite, and between the titanomagnetite and magnesioferrite-Ti mineralization in the pyroxenite of hedenbergite, seems to be analog mineralizations strongly related to the ionic substitution of Fe2+ by Mg. Relatively high Q ratios (>= 5) for Jacupirangite-pyroxenite may indicate a thermo remanent magnetization (TRM) by the ore during post-metamorphic cooling, however it call also be developed from chemical remanent magnetization (CRM). Vector plots for the pyroxenite samples show reasonably linear and stable magnetic components. The intensity decay Curves show that only two components of magnetizations are likely present. Continuous susceptibility measurements with increasing temperature show that the main magnetic phase seems to be magnetite. Maghemite is probably produced during the cooling process. Susceptibility recorded from low temperature (liquid nitrogen (- 196 degrees C)) to room temperature produces typical Curves. indicating Verwey transition of magnetite. Hysteresis parameters point Out that nearly all values fill in a novel region of the Day plot, parallel to but below magnetite SD + MD mixing curves.
ISSN: 1343-8832

hal-00420922
https://hal.archives-ouvertes.fr/hal-00420922

Éditeur(s) : HAL CCSD
Résumé : International audience
The Rif Chain (Northern Morocco) belongs, with the Betic Cordillera(Southern Spain), to the western termination of the Alpine belt. Deepestunits of the Rif Internal Zones (i.e. Lower Sebtides) outcrop in three areas, from North to South : Ceuta, Cabo Negro and Beni Bousera.The quick exhumation of these units during the Late Oligocene-EarlyMiocene is related with a crustal thinning and the Alboran Sea rifting.Despite Beni Bousera massif has been well investigated, no data areavailable in Ceuta and Cabo Negro areas. This study aims to constrainthe last steps of cooling and exhumation in the Lower Sebtides usingmedium- and low-temperature thermochronological data. Combinationof Ar-Ar on micas, fission tracks and (U-Th)/He on apatites (respectivelyAFT and AHe) from high-grade rocks allows understanding thermalhistory between 450-350°C and surface temperatures. These datasuggest a similar cooling evolution of the Ceuta and Cabo Negro units.Ages obtained with all these methods are comprised in the same interval,between 22 and 18 Ma. These data record an almost instantaneouscooling (between 50 and 200°C/Ma) associated to final exhumation afterthe Oligo-Miocene thermal event affecting these units at shallowdepths (10 km). Low-temperature data suggest that Ceuta and CaboNegro units cooled at surface temperatures before Beni Bousera ones.Since the end of Burdigalian, the Rif internal zones vertical movementsdid not exceed 1km, even during the Messinian Salinity. AFT and AHeages in the whole Sebtides are also slightly older than these obtainedin their Spanish equivalent (Alpujarrides). The Gibraltar arc is dividedinto several independent crustal blocks separated by major fault zonesperpendicular to the coast that could have induced independent verticalmovements during the entire Neogene
24 ème Réunion des sciences de la Terre 2014
Pau, France

insu-01080768
https://hal-insu.archives-ouvertes.fr/insu-01080768

Éditeur(s) : HAL CCSD
Résumé : This work focus on the characterization of the source and dynamic of compactional fluids during sedimentary burial, through two complementary examples of late orogenic oil‐field half‐grabens: The exhumed Lodève Permian Basin and a deep buried Jurassic basin in the North Viking Graben (North Sea).Constituting the main part of the thesis, a multi‐disciplinary approach was conducted in the Lodève Basin where Ba‐F‐Cu‐Pb polymetallic mineralized systems are trapped into synrift faults and paleokarsts in the carbonate basement at the hinge point of the rollover. The source, timing and P/T conditions of fluid migration were deduced from the analysis of the microfabric, the fluid inclusions microthermometry, and the isotopic (Sr, S, O, H) and Rare Earth Element (REE) signature. Results are then crossed with a structural and thermal modeling that consolidates the sequence and dynamics of fluid during burial.A similar approach was conducted in the North Viking Graben where fluid markers are restricted to 3D seismic and well core data. Comparable Ba‐Pb‐Zn veins are reported in basin margin, plugging one of the most important siliciclastic hydrocarbon reservoir in the substratum. This analysis provides additional constraints on basinal fluid behavior and allows us to propose a global dynamic model for various compositions of fluids and reservoirs.We conclude to a polyphase fluid sequence history including:(a) In the carbonate basement of the Lodève Basin, karstic paleocanyon incisions and associated cavities coupled to synrift fault, act as major drain for fluids. These structures are early affected by hypogen‐sulfuric karstification in response to the interaction between bacterial oxidation of sulfides entrapped within Lower Permian blackshales and the basement oxidizing aquifer.(b) Disequilibrium compaction initiates overpressure‐driven basinal fluid migration towards basin margins, characterized by temperatures around 150‐180°C and salinities between 9 et 18wt%eq.NaCl. Isotopic (Sr, S, O) and REE analyses reveal that Ba‐M+‐rich mineralizing fluids derived mainly from buried blackshales diagenesis. External fluids coming from the lower crust are also identified that play a key role in fluorite precipitation by the leaching of late hercynian granites (mean temperature of 250°C and salinity > 20wt%eq.NaCl).(c) During the synrift period, fluid overpressure is responsible for the periodic reactivation of fault plane according to seismic‐valve process, bedded‐control shearing and hydraulic brecciation at the basement‐seal interface. These mechanisms induce cyclic polymetallic mineralization by the mixing between in‐situ formation water and deep ascending basinal fluids.(d) Thermogenic fluids expulsion starts with last basinal fluids during late burial stage. Hydrocarbons thus migrate along the same regional pathways up to the rollover crest, where they are partly rerouted by the previous mineralized baffle.(e) In the Lodève basin, post‐rift exhumation of the margins led to the remobilization of synrift deposits by subaerial biochemical processes at the sulfate‐methane transition. The latter results from the interaction between the still active hydrocarbon dysmigration with a playa lake sulfate‐rich aquifer. Secondary low‐temperature barite fronts precipitate then within basement meteoric karsts.In addition to the « source to sink » model of basinal fluids, this work provides new insights on the early plugging of hydrocarbon reservoirs and for the metallogenesis of Mississippi Valley‐Type deposits.
Ce travail porte sur la caractérisation de la source et de la dynamique des fluides de bassin au cours de leur chargement à travers deux exemples complémentaires de demi‐grabens tardi‐orogéniques pétroliers : Le Bassin Permien de Lodève, aujourd’hui à l’affleurement et un bassin jurassique enfouis dans le North Viking Graben (Mer du Nord).Le coeur de la thèse concerne le Bassin de Lodève où, à partir d’une approche pluridisciplinaire intégrée, nous avons caractérisé l’architecture des minéralisations (Ba, F, Cu, Pb) piégées dans un réseau paléokarstique alimenté par les failles syn‐rift, dans le substratum carbonaté à l’apex du roll‐over. La source, le calendrier et les conditions de migration des fluides ont été approchés à partir de l’analyse de la micro‐fabrique, la microthermométrie sur inclusions fluides, les analyses isotopiques (Sr, S, O, H) et de Terres Rares. Les résultats analytiques ont été enfin croisés avec un modèle thermique et structural du bassin qui conforte la séquence et la dynamique du système fluide en cours d’enfouissement.Une démarche similaire, mais plus limitée, a été conduite dans le bassin du North Viking Graben où l’accès aux marqueurs fluides est restreint aux données de sismique 3D et de carottes. Comme à Lodève, les minéralisations Ba‐Pb‐Zn colmatent un réservoir dans le substratum à l’apex du roll‐over. Elles se présentent sous forme de ciments dans des grès ou des fractures. Cette analyse apporte des contraintes complémentaires et permet de proposer un modèle dynamique général avec des variantes en fonction de la nature des fluides et des réservoirs.On retiendra donc la séquence fluide suivante :(a) Dans le cas du bassin de Lodève sur substratum carbonaté, les chemins préférentiels de drainage se développent dans des paléocanyons N‐S couplés à un réseau de fractures et d’endokarsts météoriques. Ces derniers sont élargis en début de rifting par la dissolution hypogène sulfurique produite par l’oxydation bactérienne des sulfates et des pyrites des blackshales, au contact de l’aquifère oxydant du Cambrien.(b) Le déséquilibre de compaction initie la migration des fluides interstitiels en surpression vers les marges avec des températures autour de 150‐180°C et des salinités entre 9 et 18wt%eq.NaCl. Les analyses isotopiques (Sr, S, O) révèlent que la majorité des fluides provient de l’altération diagénétique des blackshales riches en métaux. Des interactions sont également mises en évidence avec des fluides profonds (entre 240°C et 260°C ; salinités > à 20wt%eq.NaCl), qui lessivent les granites tardi‐hercyniens.(c) Pendant le syn‐rift, les conditions de surpression de fluide permettent la réactivation cyclique des failles, les décollements stratigraphiques et la formation de brèches hydrauliques, favorisant la mise en connexion avec les réservoirs superficiels à l’apex du rollover. Le modèle de Sibson ajusté aux fluides de bassins est alors le moteur de la migration verticale.(d) Les fluides thermogéniques commencent à être expulsés avec les derniers fluides de compaction au cours d’un stade plus évolué de l’enfouissement en empruntant les mêmes chemins jusqu’à l’apex du roll over. Ils sont alors partiellement freinés et déviés par les colmatages minéralisés antérieurs.(e) A Lodève, la continentalisation des minéralisations antérieures au cours de l’exhumation post‐rift conduit à leur remaniement partiel au niveau de la transition sulfate‐méthane induite par l’interaction entre une playa évaporitique et la dysmigration des hydrocarbures. Des barytines secondaires de basse température, déprimées en Sr sont alors précipitées de manière synsédimentaire dans des karsts météoriques du socle.Outre l’illustration d’un modèle complet (source to sink) de dynamique des fluides dans un bassin, ce travail apporte de nouvelles contraintes dans l’approche du colmatage des réservoirs à hydrocarbures sur les têtes de blocs basculés et sur la genèse des gîtes miniers de type Mississippi Valley‐Type.
https://hal.archives-ouvertes.fr/tel-01457583

tel-01457583
https://hal.archives-ouvertes.fr/tel-01457583
https://hal.archives-ouvertes.fr/tel-01457583/document
https://hal.archives-ouvertes.fr/tel-01457583/file/th%C3%A8seLaurent2015V2.pdf

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : En 2015, de nombreux entrepreneurs haïtiens ont pris la voie de la politique en se portant candidats à divers postes électifs (maires, députés, sénateurs et président). Cette situation augure-t-elle l’apparition d’un nouveau genre d’hommes d’affaires ou leur transformation en rentiers dans le sens de Fritz A. Jean ? Pendant longtemps, les élites économique et politique étaient deux entités relativement séparées en Haïti. Il était assez rare que des entrepreneurs, pour la plupart issus de l’immigration, rentrent de façon visible dans la sphère politique. Depuis l’élargissement du tissu entrepreneurial, avec l’arrivée de beaucoup de nouveaux entrepreneurs issus de la classe moyenne et prolétarienne, ces deux dernières décennies, la tendance semble avoir changé. Notre analyse des entrepreneurs candidats aux élections de 2015, dans le cadre d’une approche associant l’institutionnalisme à la dynamique comportementale dans l’entrepreneuriat, a révélé que ces derniers, au lieu de devenir des entrepreneurs-politiciens, cessent d’être entrepreneurs pour devenir ce que nous appelons des « rentiers de la République ». Dès lors, compte tenu des dynamiques de réduction des ressources de l’État et des autres possibilités de prédation, nous montrons que la décision de ce nouveau genre d’entrepreneurs n’est efficace ni du point de vue individuel ni du point de vue collectif.
In 2015, several Haitian entrepreneurs invested the political arena and wanted to be elected at different levels (mayors, members of Parliament, and president). Does this new turn the emergence of a new kind of business men or their conversion into more voracious rent-seekers, in the sense of Fritz A. Jean? For a long time, economic and political elites were two isolated entities in Haiti. It was not common that entrepreneurs, most of the successful one are immigrants, were visibly active in politics. With the expansion of entrepreneurial context, a new trend seems to be initiated, because of the apparition of many new entrepreneurs from the middle and the lower class, during the last two decades. We analyze the case of the entrepreneurs who have run for election in the 2015-2016 political polls. We adopted a mixed approach mobilizing institutionalism and behavioral dynamic in entrepreneurship. We conclude that those candidates, instead to become entrepreneurs-in-politics, they fail to become entrepreneurs who maximize collective profit and are transformed into what we call « rent-seekers of the Republic ». But, taking into account the reduction of the State’s available resources and other depredation possibilities, we argue that the decision of this new kind of entrepreneur is effective neither from the individual point of view nor from the collective perspective.
Haïti

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.10306
http://journals.openedition.org/etudescaribeennes/10306

Éditeur(s) : Pergamon-elsevier Science Ltd
Résumé : We tested the applicability of the BIT (branched and isoprenoid tetraether) index as a proxy for palaeoflood events in the river-dominated continental margin of the Gulf of Lions (NW Mediterranean). We compared the concentrations of branched glycerol dialkyl glycerol tetraethers (br GDGTs) and crenarchaeol in suspended particulate matter (SPM) collected downstream in the Rhône River, as well as in surface sediments and a ca. 8m piston core from the Rhône prodelta. The core covered the last 400 yr, with four distinct intervals recording the river influence under natural and man-induced shifts in four main channels of the river mouth (Bras de Fer, Grand Rhône, Pégoulier,and Roustan). The results indicate that there are mixed sources of br GDGTs and crenarchaeol in the prodelta, complicating applicationof the BIT index as an indicator of continental organic carbon input and thus as a palaeoflood proxy. However, the sedimentary BIT record for the period when continental material was delivered by the river more directly to the core site (Roustan phase;1892 to present) mimics the historical palaeoflood record. This shows the potential of the BIT index as a palaeoflood proxy, provided that the delivery route of the continental material by rivers to the core sites remains constant over time. The study also highlights the idea that shifts in river channels should be taken into account for the use of the BIT index as a palaeoflood proxy.
Organic Geochemistry (0146-6380) (Pergamon-elsevier Science Ltd), 2014-10 , Vol. 75 , P. 99-108

Droits : 2014 Elsevier Ltd. All rights reserved.
http://archimer.ifremer.fr/doc/00198/30969/29345.pdf
DOI:10.1016/j.orggeochem.2014.06.011
http://archimer.ifremer.fr/doc/00198/30969/

Éditeur(s) : NRC
Résumé : Universal kriging was used to model the spatio-temporal variability in the acoustic density of tuna aggregations recorded during star echosounding surveys around moored fish aggregating devices (FADs) in Martinique (Lesser Antilles). The large-scale deterministic drift in the tuna spatial distribution was modeled using an advection-diffusion equation applied to animal grouping. Residuals from the drift were modeled as a random component with small-scale spatial correlation. An estimation variance formula was derived from this deterministic-statistical mixed model to assess the mean precision of density estimates of daytime tuna aggregation. The mean relative error obtained with our star design for daytime surveys was 24%. The methodology was applied to estimate daily maxima of tuna biomass around moored FADs during four monthly sea cruises. The daily peak of tuna biomass aggregated around moored FADs was 9 t on average (standard deviation = 4). Estimation variances for different survey designs were compared for optimizing sampling strategy.
La distribution spatiale d'agrégations de thons autour de dispositifs de concentration de poissons (DCP) ancrés a été étudiée en Martinique (Petites Antilles) au moyen de parcours acoustiques en étoile. Les densités acoustiques géoréférencées attribuées aux thons ont été analysées à l'aide d'un modèle de krigeage universel. Une tendance à large échelle a été identifiée dans la distribution spatiale des thons. Cette tendance a été modélisée de façon déterministe au moyen d'une équation d'advection–diffusion appliquée aux groupes d'animaux. Les résidus de la tendance ont été modélisés comme une composante aléatoire du modèle, spatialement corrélée à faible échelle. De ce modèle, qui contenant une composante déterministe et une composante statistique, a été déduite une formule permettant de calculer la variance d'estimation de la densité diurne moyenne de l'agrégation de thons autour des DCP. L'erreur relative moyenne commise sur l'estimation de la densité de thons lors d'un parcours en étoile diurne a été estimée à 24 %. Cette méthode a été appliquée afin d'estimer les maxima journaliers de biomasse de l'agrégation de thons observés lors de quatre campagnes en mer mensuelles successives autour des DCP ancrés. La biomasse maximale de thons agrégée autour des DCP ancrés durant une phase diurne était en moyenne de 9 t (écart type : 4). Les variances d'estimation obtenues avec différents parcours acoustiques ont été comparées afin d'optimiser la stratégie d'échantillonnage.
Canadian journal of fisheries and aquatic sciences (0706-652X) (NRC), 2008-06 , Vol. 65 , N. 6 , P. 1193-1205

Droits : 2008 National Research Council Canada
http://archimer.ifremer.fr/doc/2008/publication-4559.pdf
DOI:10.1139/F08-050
http://archimer.ifremer.fr/doc/00000/4559/

Éditeur(s) : HAL CCSD
Résumé : In this paper we report a study of the mating system and gene flow of Sextonia rubra, a hermaphroditic, insect pollinated tropical tree species with a geographic distribution in the Guyana Plateau and the Amazon. Using five microsatellites we analysed 428 seeds of 27 open pollinated families at the experimental site "Paracou" in French Guiana. We observed, compared to other tropical tree species, a high level of genetic diversity. We estimated parameters of the mating system and gene flow by using the mixed mating model and the TwoGenerapproach. The estimated multilocus outcrossing rate, tm, was 0.992 indicating nearly complete outcrossing. A significant level of biparental inbreeding and a small proportion of full-sibs were estimated for the 27 seed arrays. The differentiation of allelic frequencies among the pollen pools was ΦFT = 0.061. We estimated mean pollen dispersal distances between 65 m and 89 m according to the dispersal models used. The joint estimation of pollen dispersal and density of reproductive trees gave an effective density estimate of 2.1-2.2 trees/ha
Silvae genetica

hal-01031483
https://hal.archives-ouvertes.fr/hal-01031483

Éditeur(s) : HAL CCSD
Résumé : International audience
Acute viral hepatitis results from an inefficient innate immune response to clear the virus and a delayed immune adaptive response. Murine hepatitis virus (MHV) infection represents a unique animal model to identify new escape mechanisms in liver of innate immune responses. The objective of this study was to identify early disorders in TLRs, helicases, cytokines and chemokines favoring the development of a fulminant hepatitis. Groups of C57BL/6 WT and TLR2-/- mice were infected with highly hepatotropic MHV3 and/or weakly hepatotropic MHV-A59 viruses. Histopathological analysis of liver and mRNA expression levels of viral nucleoprotein, viral sensors, interferons, cytokines and chemokines assessed by RT-qPCR were done in the first 3 days of infection. The results showed that liver damages, viral replication and mRNA levels of TLR-2, TLR-3, RIG-1, MDA-5, IL-33, IFN-b, CXCL1, CXCL9, CXCL-10, CXCL-11, CCL3, CCL5, IL-6 and TNF-a increased higher or appeared sooner in MHV3-infected WT than in MHV-A59 and TLR2-/- mice. To address the role of hepatocytes in TLR2-dependent viral replication and innate immune factors, in vitro viral infections were performed on FL83B cells. The results showed that viral replication and mRNA levels of TLR-2 and IL-6 occurred sooner than those of other innate immune parameters. Moreover, blockade of TLR-2 by siRNA decreased IFN-b, TNF-a, CXCL-1, CXCL-10 and CCL-2 expression in infected hepatocytes and also inhibited the viral replication of MHV-A59, and at a lesser extent of MHV3, suggesting that TLR-2 signaling promotes simultaneously the viral replication and the production of innate immune factors in hepatocytes, exacerbating viral hepatitis.
Frontiers of Immunology
Milan, Italy

hal-01118155
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01118155
DOI : 10.3389/conf.fimmu.2013.02.00648

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : La notion du tourisme moteur de développement n’a pas survécu à la chute du communisme. Cette chute a rendu caduc, le rôle idéologique de ce secteur, symbole et acteur du libéralisme au temps de la guerre froide. De fait, le tourisme retrouve sa place « normale » parmi les vocations nationales des pays en développement : aide au développement et/ou lutte contre la pauvreté !Le Maroc, l’un des pionniers du libéralisme en Afrique, n’a pas échappé aux conséquences du suivisme économique propre aux pays d’Afrique, socialistes et libéraux confondus. Du tourisme moteur de développement (1964), il a récemment procédé au réajustement de sa stratégie en matière du développement touristique, en en faisant un secteur d’appoint pour l’économie nationale. « Le miracle économique du tourisme n’a donc pas eu lieu ! » (Hillali, 2007). Constat d’échec ou réajustement stratégique normal, la question est posée. À ce propos, deux initiatives méritent d’être citées :- Le tourisme représente un secteur d’activité qui procure emplois et revenus aux citadins démunis (artisanat, emplois peu qualifiés...) et aux populations rurales (gites, auberges, accompagnement...) dans le cadre de la nouvelle stratégie des Pays d’accueil touristiques (2003), du tourisme de niches et de l’aide aux jeunes entrepreneurs. - L’initiative nationale du développement humain (INDH), lancée en 2004, est censée épauler les nécessiteux dans cette politique sociale et économique de grande envergure.Or, en dépit des programmes bien planifiés, les résultats sont mitigés. Peut-être, est-il que la mise en pratique de ces nouvelles approches de développement local et ciblé (actions opérationnelles) et les méthodes d’évaluation qui en assurent le suivi (mesure des impacts) ne sont pas encore assez rôdées.
The concept of tourism as a driving force for development has not survived the fall of communism. The end of the Cold War rendered the ideological role of the tourism sector, as a main tool of liberalism, obsolete. Today, the most common setting for the tourism sector is in developing countries, as a tool for development and/or poverty reduction.Morocco, one of the pioneers of liberalism in Africa, has not escaped the consequences of the economic band wagonning among African states, socialists and liberals alike. A driving force for tourism development in the last century (1964), Morocco has recently readjusted its strategy to create an extra sector to contribute to the national economy. "The economic miracle of tourism has not taken place!"(Hillali, 2007). The question is posed: What is more appropriate, identifying failures or engaging in strategic readjustment? In this regard, two initiatives are worth mentioning: - Tourism is an industry that provides jobs and income for the urban (crafts, low-skilled jobs) and rural (cottages, inns, coaching) poor as part of the new strategy of the country’s tourist reception (2003), tourism niches and helping young entrepreneurs. - The National Initiative for Human Development (NIHD), launched in 2004, aims to support those in need in major social and economic policies.However, despite well-planned programs, the results have been mixed. Perhaps it is that the implementation of these new approaches to local development and targeted (operational activities) and evaluation methods that ensure monitoring (measurement of impacts) do not overlap enough.
Afrique
Maroc

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.6563
http://journals.openedition.org/etudescaribeennes/6563

Éditeur(s) : HAL CCSD European Geosciences Union
Résumé : We designed a thermo-mechanical numerical model for fast-spreading mid-ocean ridge with variable viscosity, hydrothermal cooling, latent heat release, sheeted dyke layer, and variable melt intrusion possibilities. The model allows for modulating several accretion possibilities such as the "gabbro glacier" (G), the "sheeted sills" (S) or the "mixed shallow and MTZ lenses" (M). These three crustal accretion modes have been explored assuming viscosity contrasts of 2 to 3 orders of magnitude between strong and weak phases and various hydrothermal cooling conditions depending on the cracking temperatures value. Mass conservation (stream-function), momentum (vorticity) and temperature equations are solved in 2-D cartesian geometry using 2-D, alternate direction, implicit and semi-implicit finite-difference scheme. In a first step, an Eulerian approach is used solving iteratively the motion and temperature equations until reaching steady states. With this procedure, the temperature patterns and motions that are obtained for the various crustal intrusion modes and hydrothermal cooling hypotheses display significant differences near the mid-ocean ridge axis. In a second step, a Lagrangian approach is used, recording the thermal histories and cooling rates of tracers travelling from the ridge axis to their final emplacements in the crust far from the mid-ocean ridge axis. The results show that the tracer's thermal histories are depending on the temperature patterns and the crustal accretion modes near the mid-ocean ridge axis. The instantaneous cooling rates obtained from these thermal histories betray these discrepancies and might therefore be used to characterize the crustal accretion mode at the ridge axis. These deciphering effects are even more pronounced if we consider the average cooling rates occurring over a prescribed temperature range. Two situations were tested at 1275-1125 °C and 1050-850 °C. The first temperature range covers mainly the crystallization range that is characteristic of the high temperature areas in the model (i.e. the near-mid-oceanic-ridge axis). The second temperature range corresponds to areas in the model where the motion is mainly laminar and the vertical temperature profiles are closer to conductive. Thus, this situation results in less discriminating efficiency among the crustal accretion modes since the thermal and dynamic properties that are described are common to all the crustal accretion modes far from the ridge axis. The results show that numerical modeling of thermo-mechanical properties of the lower crusts may bring useful information to characterize the ridge accretion structure, hydrothermal cooling and thermal state at the fast-spreading ridges and may open discussions with petrological cooling rate results.
ISSN: 1991-959X

hal-00907012
https://hal.archives-ouvertes.fr/hal-00907012
DOI : 10.5194/gmd-6-1659-2013

Éditeur(s) : HAL CCSD
Résumé : The Restefond fault, located in the Late Eocene-Early Oligocene Alpine foreland basin, affects the well lithified and low porosity Grès d'Annot. The fault core zone is characterized by the occurrence of highly deformed sandstone lenses. Deformation inside the lenses corresponds to mm to sub-mm-spaced cleavage planes rich in phyllosilicates and up to cm-thick and dm-long quartz-calcite pure extensional veins. The cleavages are mostly composed of newly-formed synkinematic white mica and chlorite. By using thermodynamic thermometers based on the chemical composition of chlorite, a temperature of 200 ± 20 °C of fault activity was computed. This temperature shows that the Restefond fault was active at burial conditions comprised between 6.5 and 8 km, assuming a mean geothermal gradient between 25 and 30 °Ckm−1. The petrophysic properties of sandstones from the core zone and in the hanging and foot wall of the fault were determined on drilled plugs following three spacial directions. The permeability of the highly deformed sandstone from the core zone is about one order of magnitude higher than in the host rock. This increase in permeability occurs in the direction parallel to the S-C structures and is explained by the occurrence of well-connected micropores localized between platy phyllosilicates. This study shows that the fault petrophysic properties are mostly controlled by the precipitation of synkinematic phyllosilicates under deep burial conditions.
Swiss Journal of Geosciences

hal-00795551
https://hal.archives-ouvertes.fr/hal-00795551
DOI : 10.1007/s00015-012-0099-z

Éditeur(s) : Elsevier
Résumé : The distribution, partition and speciation of mercury (Hg) were studied along the redox gradient of an anthropogenically perturbed tropical estuary, the Sinnamary Estuary in French Guiana. This system is a partially mixed estuary characterized by an anoxic freshwater end-member, while the marine end member consists of the Amazon Plume. The set up of an artificial oxygenation system in the anoxic freshwater end-member generates sharp gradients of major chemical species (iron, sulfides, etc.) coupled with intense organic matter (OM) turnover. The coexistence of oxygenated waters and dissolved sulfides in an organic rich environment depicts the Upper Sinnamary Estuary (USE: part of Sinnamary Estuary under the tidal influence but upstream of the salt intrusion) as a potential site for Hg methylation. The concentrations of all mercurial species (HgT) in the unfiltered samples (HgTUNF), in the dissolved (HgTD) and particulate (HgTP) phases of the USE average 11 ± 3, 6 ± 2 and 5 ± 3 (i.e. 600 ± 200 pmol g-1) pmol L-1 respectively. Average concentrations of monomethylmercury (MMHg) in the unfiltered (MMHgUNF), dissolved (MMHgD) and particulate (MMHgP) phases were 3.7 ± 1.0, 2.0 ± 0.9 and 1.8 ± 1.2 (i.e. 220 ± 130 pmol g-1) pmol L-1 respectively. Water oxygenation and sulfides concentrations emerged to play a critical role in controlling MMHg levels. Additionally, iron cycling, acid-base mechanisms, and edoxdependent processes were involved in the MMHg partitioning between phases. Overall, the USE constitutes a biogeochemical reactor that gathers partitioning and methylation processes. Thepermanent MMHg inputs from the anoxic freshwater end-member combined with the intense endogenous Hg methylation ensures high MMHg levels in both dissolved and particulate phases. To illustrate, the USE exports 60 ± 20 % more MMHgUNF than it imports: 5.5 ± 0.7 vs. 3.5 ± 1.2 kg y-1.
Geochimica et Cosmochimica Acta (0016-7037) (Elsevier), 2008-07 , Vol. 72 , N. 22 , P. 5416-5430

Droits : 2008 Elsevier Ltd. All rights reserved
http://archimer.ifremer.fr/doc/2008/publication-4223.pdf
DOI:10.1016/j.gca.2008.08.021
http://archimer.ifremer.fr/doc/00000/4223/