Generation of Silicic Melts in the Early Izu-Bonin Arc Recorded by Detrital Zircons in Proximal Arc Volcaniclastic Rocks From the Philippine Sea

A 1.2 km thick Paleogene volcaniclastic section at International Ocean Discovery Program Site 351-U1438 preserves the deep-marine, proximal record of Izu-Bonin oceanic arc initiation, and volcano evolution along the Kyushu-Palau Ridge (KPR). Pb/U ages and trace element compositions of zircons recovered from volcaniclastic sandstones preserve a remarkable temporal record of juvenile island arc evolution. Pb/U ages ranging from 43 to 27 Ma are compatible with provenance in one or more active arc edifices of the northern KPR. The abundances of selected trace elements with high concentrations provide insight into the genesis of U1438 detrital zircon host melts, and represent useful indicators of both short and long-term variations in melt compositions in arc settings. The Site U1438 zircons span the compositional range between zircons from mid-ocean ridge gabbros and zircons from relatively enriched continental arcs, as predicted for melts in a primitive oceanic arc setting derived from a highly depleted mantle source. Melt zircon saturation temperatures and Ti-in-zircon thermometry suggest a provenance in relatively cool and silicic melts that evolved toward more Th and U-rich compositions with time. Th, U, and light rare earth element enrichments beginning about 35 Ma are consistent with detrital zircons recording development of regional arc asymmetry and selective trace element-enriched rear arc silicic melts as the juvenile Izu-Bonin arc evolved.Support for this research was provided by the IODP, the United States Implementing Organization, and the U.S. National Science Foundation through grant NSF OCE-1558830 to AP

The choroid plexus as a sex hormone target: Functional implications

The choroid plexuses (CPs) are highly vascularized branched structures that protrude into the ventricles of the brain, and form a unique interface between the blood and the cerebrospinal fluid (CSF). In recent years, novel functions have been attributed to this tissue such as in immune and chemical surveillance of the central nervous system, brain development, adult neurogenesis and circadian rhythm regulation. Sex hormones (SH) are widely recognized as modulators in several neurodegenerative diseases, and there is evidence that estrogens and androgens regulate several fundamental biological functions in the CPs. Therefore, SH are likely to affect the composition of the CSF impacting on brain homeostasis. This review will look at implications of the CPs' sex-related specificities.Portuguese Foundation for Science and Technology (FCT, Portugal – http://www.fct.pt) project grants (PTDC/SAU-NEU/114800/2009); and by FEDER funds through the POCI – COMPETE 2020 – Operational Programme Competitiveness and Internationalisation in Axis I – Strengthening research, technological development and innovation (Project No. 007491) and National Funds by FCT – Foundation for Science and Technology (Project UID/Multi/00709). Joana Tomás was supported by a grant from CENTRO-07-ST24-FEDER-002015. Telma Quintela is a recipient of a FCT fellowship (SFRH/BPD/70781/2010). The work at ICVS/3B’s has the support of Portuguese North Regional Operational Program (ON.2 – O Novo Norte) under the National Strategic Reference Framework (QREN), through the European Regional Development Fund (FEDER). Fernanda Marques is a recipient of a FCT Investigator award (IF/00231/2013) of the Fundação para a Ciência e Tecnologia (FCT, Portugal)info:eu-repo/semantics/publishedVersio

A record of spontaneous subduction initiation in the Izu–Bonin–Mariana arc

The initiation of tectonic plate subduction into the mantle is poorly understood. If subduction is induced by the push of a distant mid-ocean ridge or subducted slab pull, we expect compression and uplift of the overriding plate. In contrast, spontaneous subduction initiation, driven by subsidence of dense lithosphere along faults adjacent to buoyant lithosphere, would result in extension and magmatism. The rock record of subduction initiation is typically obscured by younger deposits, so evaluating these possibilities has proved elusive. Here we analyse the geochemical characteristics of igneous basement rocks and overlying sediments, sampled from the Amami Sankaku Basin in the northwest Philippine Sea. The uppermost basement rocks are areally widespread and supplied via dykes. They are similar in composition and age—as constrained by the biostratigraphy of the overlying sediments—to the 52–48-million-year-old basalts in the adjacent Izu–Bonin–Mariana fore-arc. The geochemical characteristics of the basement lavas indicate that a component of subducted lithosphere was involved in their genesis, and the lavas were derived from mantle source rocks that were more melt-depleted than those tapped at mid-ocean ridges. We propose that the basement lavas formed during the inception of Izu–Bonin–Mariana subduction in a mode consistent with the spontaneous initiation of subduction

Evolutionary diversification of new caledonian Araucaria

New Caledonia is a global biodiversity hotspot. Hypotheses for its biotic richness suggest either that the island is a ‘museum’ for an old Gondwana biota or alternatively it has developed following relatively recent long distance dispersal and in situ radiation. The conifer genus Araucaria (Araucariaceae) comprises 19 species globally with 13 endemic to this island. With a typically Gondwanan distribution, Araucaria is particularly well suited to testing alternative biogeographic hypotheses concerning the origins of New Caledonian biota. We derived phylogenetic estimates using 11 plastid and rDNA ITS2 sequence data for a complete sampling of Araucaria (including multiple accessions of each of the 13 New Caledonian Araucaria species). In addition, we developed a dataset comprising 4 plastid regions for a wider taxon sample to facilitate fossil based molecular dating. Following statistical analyses to identify a credible and internally consistent set of fossil constraints, divergence times estimated using a Bayesian relaxed clock approach were contrasted with geological scenarios to explore the biogeographic history of Araucaria. The phylogenetic data resolve relationships within Araucariaceae and among the main lineages in Araucaria, but provide limited resolution within the monophyletic New Caledonian species group. Divergence time estimates suggest a Late Cretaceous-Cenozoic radiation of extant Araucaria and a Neogene radiation of the New Caledonian lineage. A molecular timescale for the evolution of Araucariaceae supports a relatively recent radiation, and suggests that earlier (pre-Cenozoic) fossil types assigned to Araucaria may have affinities elsewhere in Araucariaceae. While additional data will be required to adequately resolve relationships among the New Caledonian species, their recent origin is consistent with overwater dispersal following Eocene emersion of New Caledonia but is too old to support a single dispersal from Australia to Norfolk Island for the radiation of the Pacific Araucaria sect. Eutacta clade.Mai Lan Kranitz, Edward Biffin, Alexandra Clark, Michelle L. Hollingsworth, Markus Ruhsam, Martin F. Gardner, Philip Thomas, Robert R. Mill, Richard A. Ennos, Myriam Gaudeul, Andrew J. Lowe, Peter M. Hollingswort

Conception et réalisation d\u27une instrumentation dédiée à la prédiction du confort d\u27assise et à la prévention des escarres

La mesure objective du confort ressenti est une nouvelle étape nécessaire dans le domaine de l\u27habitat intelligent et la prévention médicale. L\u27objectif de cette thèse est la conception et le développement de nouveaux moyens d\u27étude du confort d\u27assise et de prévention des escarres. A partir d\u27une étude physiologique du confort et du processus de formation des escarres, deux solutions principales sont proposées. La première est la mise en oeuvre d\u27une méthodologie multi-paramétrique, basée sur la mesure de l\u27activité du Système Nerveux Autonome. La deuxième est basée sur la conception d\u27une matrice de capteurs actifs de mesure de pression d\u27interface. Les premières expériences sont présentées à la fin de ce mémoire

Styles of Cenozoic collisions in the western and southwestern Pacific and their applications to Palaeozoic collisions in the Tasmanides of eastern Australia

The western and southwestern Pacific preserve evidence of Cenozoic collisions that guide our understanding of processes and geometries involved in collisions in ancient orogens, in particular in this case, the Palaeozoic Tasmanides of southeastern Australia. Although several styles of collisions are present in the Pacific, ranging from arc-arc collision to arc-plateau collision, the dominant two are oblique and strike-slip collisions between island arcs and rifted continental fragments, and collisions between forearc lithosphere and continental fragments. The 58 Ma collision along the northern margin of the Australian plate in New Guinea, the 44-34 Ma collision preserved in New Caledonia and the 26-25 Ma collision in the North Island of New Zealand may be parts of a single plate boundary collision that migrated southwards along the plate boundary. They characterize the main style of deformation in which a collision between forearc crust and continental fragment produces subduction flip or rollback, thereby avoiding a classic arc-continent collision. Processes involved in, and geometries that have developed from, SW and W Pacific style collisions have been applied to the interpretation of the evolution of the Delamerian Orogen and Lachlan Orogen in the southern Tasmanides with varying degrees of success. The ophiolite obduction model has been successfully applied to the western Tasmania part of the Delamerian Orogen, although there is discussion about its applicability to the mainland. The best example of an arc accretion, that of the Ordovician Macquarie Arc in the eastern Lachlan Orogen, developed from rare geometry in the western Pacific wherein (with the constraint that no forearc or subduction complex has been identified) the arc lies on the continental plate, above a continental-dipping subduction zone. The multiple subduction zone model of Halmahera has been widely applied to the back arc of the Lachlan Orogen, but evidence for clear subduction zones or arcs is not present.20 page(s

Which techniques to improve the early detection and prevention of pressure ulcers?

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PTPN22 inhibition resets defective human central B cell tolerance

The 1858T protein tyrosine phosphatase nonreceptor type 22 (PTPN22 T) allele is one of the main risk factors associated with many autoimmune diseases and correlates with a defective removal of developing autoreactive B cells in humans. To determine whether inhibiting PTPN22 favors the elimination of autoreactive B cells, we first demonstrated that the PTPN22 T allele interfered with the establishment of central B cell tolerance using NOD-scid-common γ chain knockout (NSG) mice engrafted with human hematopoietic stem cells expressing this allele. In contrast, the inhibition of either PTPN22 enzymatic activity or its expression by RNA interference restored defective central B cell tolerance in this model. Thus, PTPN22 blockade may represent a therapeutic strategy for the prevention or treatment of autoimmunity