Pre-Eocene Synmetamorphic Structure in the Mindoro-Romblon-Palawan Area, West Philippines, and implications for the history of southeast Asia

International audienceThe structure of the pre-Eocene rocks, considered as the "basement" of the Philippines, has been investigated in the Mindoro-Lubang, Romblon-Tablas-Sibuyan, and North Palawan areas. In the former two areas the same pre-Eocene succession of units is recognized from top to bottom: (1) a pre-Eocene olistostrome; (2) an ophiolitic nappe; (3) a schistose sequence (pelites, sandstones, basic schists and marbles); and (4) a gneissic unit. The nature of the contact between the olistostrome and the underlying units is unclear, but the ophiolite and the schistose sequence form two thrust sheets of oceanic origin thrust upon the gneissic unit that is considered a part of a continental basement called the West Philippines Block. Small-scale structures show that the early deformation stage is characterized by a submeridian (0°-N40°E) lineation formed in greenschist to amphibolite facies conditions during the thrusting. Kinematic analysis show that the thrusting was from north to south. In North Palawan, metamorphic rocks with similar microtectonic and kinematic characteristics are found. They are overlain by a Late Jurassic olistostrome which is correlated with the olistostromes found in Calamian, North Mindoro, Carabao, and Buruanga peninsula (North Panay). The microstructural features and the presence of the olistostrome suggest that the North Palawan, Mindoro, Tablas, Romblon, Sibuyan, and Carabao islands belong to the same North Palawan block of Hamilton (1979) which is a continental fragment rifted from Asia in Cenozoic times. It is assumed that the Western Panay and Zamboanga areas, which are characterized by Mesozoic ophiolites and metamorphic rocks, also belong to the North Palawan Block. All these islands experienced, to some extent, the same Mesozoic geohistory: the south verging thrusting is interpreted as the result of an oblique collision of the West Philippines Block with Asia. The contemporaneous left-lateral strike-slip faulting and the calc-alkaline magmatism widespread along the Chinese margin are also included in the geodynamic model

Le statut du nom Hippopotamus madagascariensis Guldberg, 1883. Réponse à Rakotovao et al. 2014

International audienceM. Rakatovao, Y. Lignereux et al. (2014) viennent de publier une étude anatomique crânio-dentaire des spécimens d'hippopotames malgaches de la Collection Galliéni conservés au Museum d'Histoire naturelle de Toulouse. Cette étude a, dans un premier temps, fait l'objet d'un mémoire de Master 2 réalisé sous la direction de Y. Lignereux, F. Duranthon & P. O. Antoine, et soutenu en 2007 (Rakotovao 2007). Dans ce travail, que Rakotovao et al. (2014) n'ont pas jugé utile de citer, Rakotovao conclut « Nos recherches ont montré que, essentiellement sur la base des caractères crâniens, (…), les spécimens du MHNT appartiennent à l'espèce H. lemerlei. Dans leur publication récente, ces auteurs considèrent maintenant, toujours à partir des seuls caractères crâniens, que les deux petites espèces malgaches sont présentes dans la collection du Muséum de Toulouse. [...

A ρ-Calculus of Explicit Constraint Application

AbstractTheoretical presentations of the ρ-calculus often treat the matching constraint computations as an atomic operation although matching constraints are explicitly expressed. Actual implementations have to take a much more realistic view: computations needed in order to find the solutions of a matching equation can be really important in some matching theories and the substitution application usually involves a term traversal.Following the works on explicit substitutions in the λ-calculus, we propose, study and exemplify a ρ-calculus with explicit constraint handling, up to the level of substitution applications. The approach is general, allowing the extension to various matching theories. We show that the calculus is powerful enough to deal with errors. We establish the confluence of the calculus and the termination of the explicit constraint handling and application sub-calculus

Bref historique des services de renseignement et de sécurité français contemporains

Guerre froide, terrorisme international, intelligence économique : les services de renseignement et de sécurité français ont dû, ces soixante dernières années, s’adapter à la situation internationale et s’organiser en conséquence. Ils ont néanmoins conservé leurs rôles respectifs, hérités de la période fondatrice qu’a été la Seconde Guerre mondiale. Depuis, les actions qu’ils ont entreprises ont toujours obéi à la mission nationale fixée par le gouvernement.A short history of the contemporary French secret and security services. Cold War, international terrorism, economic intelligence: the French secret and security services have had to adapt themselves over the past sixty years to an evolving international situation and to organise themselves in accordance with these changes. The services have nevertheless preserved their respective roles as they inherited them from the foundational period of the Second World War. Since that time the actions they have carried out have always adhered to the national mission determined by the French government

Decreased Expression of Epidermal Cytoplasmic Antigens in Cultured Human Keratinocytes

The expression of upper cytoplasmic (U-CYT) antigens which are expressed only in the superficial layers of the epidermis and are markers of epidermal cell differentiation in vivo and of basement zone (BMZ) antigens reacting with bullous pemphigoid serum was studied in keratinocytes in tissue culture. The cells were cultured at an acid pH (5.6–5.8) similar to that of skin and without feeder cells, dermal tissue, or collagen. It was found that the expression of U-CYT antigens decreased markedly in culture. These antigens were expressed in 45–65% of epidermal cells prepared from fresh skin, but in only 5–10% of cells which had been grown in primary culture over 1 mo, and in no cells in secondary or tertiary culture. By contrast, BMZ antigens continued to be expressed in culture. These antigens were expressed by 20–35% of epidermal cells prepared from fresh tissue and by 15–35% of keratinocytes in primary, secondary or tertiary culture. These findings indicate that U-CYT and BMZ antigens can be used to type subpopulations of human keratinocytes in suspension, and suggest that the differentiation of these cells in vitro differs from that which occurs in vivo

Triassic tectonics of the southern margin of the South China Block

International audienceMiddle Triassic orogens are widespread around and inside the South China Block (SCB). The southern peripheral belts that develop from northwest to southeast, namely Jinshajiang, Ailaoshan, NW Vietnam, NE Vietnam, Yunkai and Hainan exhibit striking similarities, with Permian–Early Triassic magmatic arc, ophiolitic mélange, northeast- to north-directed synmetamorphic ductile nappes, and fold-and-thrust belt. These collisional belts result from oceanic, then continental subduction of the SCB below Indochina. Eastward of Hainan Island, a Triassic suture is hypothesized offshore of the SCB. Within the SCB, the Xuefengshan is a Middle Triassic intracontinental orogen with northwest-directed folds and thrusts, and an intracrustal ductile décollement. This orogen accommodated the Middle Triassic continental subduction of the western part of the SCB below the eastern part. At variance to the generally accepted models, the inter- and intracontinental Triassic orogens of the SCB are interpreted here as the result of south-directed subductions of the SCB

A novel p21-activated kinase binds the actin and microtubule networks and induces microtubule stabilization

Coordination of the different cytoskeleton networks in the cell is of central importance for morphogenesis, organelle transport, and motility. The Rho family proteins are well characterized for their effects on the actin cytoskeleton, but increasing evidence indicates that they may also control microtubule (MT) dynamics. Here, we demonstrate that a novel Cdc42/Rac effector, X-p21-activated kinase (PAK)5, colocalizes and binds to both the actin and MT networks and that its subcellular localization is regulated during cell cycle progression. In transfected cells, X-PAK5 promotes the formation of stabilized MTs that are associated in bundles and interferes with MTs dynamics, slowing both the elongation and shrinkage rates and inducing long paused periods. X-PAK5 subcellular localization is regulated tightly, since coexpression with active Rac or Cdc42 induces its shuttling to actin-rich structures. Thus, X-PAK5 is a novel MT-associated protein that may communicate between the actin and MT networks during cellular responses to environmental conditions

A rho-calculus of explicit constraint application.

International audienceTheoretical presentations of the rho-calculus often treat the matching constraint computations as an atomic operation although matching constraints are explicitly expressed. Actual implementations have to take a much more realistic view: computations needed in order to find the solutions of a matching equation can be really important in some matching theories and the substitution application usually involves a term traversal. Following the works on explicit substitutions in the λ-calculus, we propose, study and exemplify a rho-calculus with explicit constraint handling, up to the level of substitution applications. The approach is general, allowing the extension to various matching theories. We show that the calculus is powerful enough to deal with errors. We establish the confluence of the calculus and the termination of the explicit constraint handling and application sub-calculus

New geological and tephrochronological data on the palaeontological site of the Senèze maar (Early Pleistocene, Massif Central, France)

The volcanic system of Senèze (Domeyrat, Haute-Loire) comprises a basanite flow, scoriae, a maar crater and phreatomagmatic products. New field research and detailed cartography clarify their geometry and geological relationships. The maar contains an important palaeontological site of the Early Pleistocene that yielded forty species of mammals attributed to the biozone MNQ 18 (of which it is the reference locality). The excavations undertaken between 2001 and 2006 recovered new fossils and documented their stratigraphic and geodynamic context. The fossiliferous site is located on the shore of the palaeolake and includes several lacustrine and slope deposits linked to the contemporaneous climatic changes which in turn produced a number of locally fossiliferous findspots which appear to be close in age. The discovery of ten tephras emitted by the Mont-Dore strato-volcano, situated 60 km to the NW allowed development of a remarkable tephrochronological framework. Because of the intense weathering of the tephras, their composition is determined by their mineralogical content (feldspars, brown amphiboles, brown and green diopside, titanite, apatite, zircon, biotite-phlogopite, Fe-Ti oxides) and the chemical composition of feldspars (anorthoclase, sodic sanidine and plagioclases). The study of these tephras reveals the importance of the contemporaneous (mainly trachytic) pyroclastic activity and confirms the polyphased deposition of the site. The 40Ar/39Ar laser dating of alkali feldspars from five tephras shows a relatively narrow range of age comprised between 2.09 and 2.21 \textpm 0.02 Ma (1σ, age relative to ACs-2 standard at 1.201 Ma). Senèze is thus confirmed as a key Early Pleistocene palaeontological site in Europe