412 research outputs found
Quotient probabilistic normed spaces and completeness results
Quotient spaces of probabilistic normed spaces have never been considered. This note is a first attempt to fill this gap: the quotient space of a PN space with respect to one of its subspaces is introduced and its properties are studied. Finally, we investigate the completeness relationship among the PN spaces considered
Translithospheric Mantle Diapirism: Geological Evidence and Numerical Modelling of the Kondyor Zoned Ultramafic Complex (Russian Far-East)
We report new structural, microstructural, petrological, and major- and trace-element data on ultramafic rocks from the Kondyor zoned ultramafic complex in Far-East Russia. The ultramafic rocks are subdivided into three subconcentric lithologies, from core to rim: (1) a metasomatic domain where generally phlogopite-rich dykes pervasively intrude dunite; (2) a main dunite core; (3) a pyroxenite rim. The ultramafic rocks have nearly vertical contacts with the surrounding Archaean basement (gneisses, quartzites and marbles) and hornfelsed Riphean sediments. The hornfelsed sediments show a relatively steep (> 60°), outward dipping layering, which rapidly flattens to horizontal away from the inner contact. Although the Riphean sediments define a dome-like structure, the inward, shallow dipping foliation of the dunites indicates a synformal structure. Detailed petro-structural investigations indicate that the Kondyor dunites were deformed by solid-state flow under asthenospheric mantle conditions. The outward textural change from coarse- to fine-grained equigranular dunite and the outward-increasing abundance of subgrains and recrystallized olivine grains suggest dynamic recrystallization while fluid circulation was channelized within the core metasomatic zone, with a decreasing melt fraction from core to rim, and also suggest that solid-state deformation induced grain-size reduction towards the cooling border of the Kondyor massif. Based on their geochemistry, the dunites are interpreted as mantle rocks strongly affected by reaction with melts similar to the Jurassic-Cretaceous Aldan Shield lamproites. Rim pyroxenites were formed by a melt-consuming peritectic reaction, implying the existence of at least a small, conductive thermal gradient around the dunite body while the latter was still at near-solidus temperature conditions. This suggests that the zoned structure of Kondyor was initiated at mantle depths, most probably within the subcontinental lithosphere. Upon cooling, the lamproitic melts were progressively focused in the central part of the massif and drained into vein conduits where they reacted with the wall-rock dunite. Two-dimensional numerical modelling based on finite-differences with a marker-in-cell technique incorporates temperature-dependent rheologies for both molten and non-molten host rocks. The modelling consolidates the structural, petrological and geochemical interpretations, which show that the dunites represent the synformal, flat-lying apex of an asthenospheric mantle diapir, triggered by fluid pressure channelized in the core, which nearly reached the Earth's surface. We conclude that translithospheric mantle diapirism is an important mode of mass transfer in theEart
Petrogenesis of crustal wehrlites in the Oman ophiolite: Experiments and natural rocks
In the Wadi Haymiliyah of the Oman ophiolite (Haylayn block), discordant wehrlite bodies ranging in size from tens to hundreds of meters intrude the lower crust at different levels. We combined investigations on natural wehrlites from the Wadi Haymiliyah section with an experimental study on the phase relations in a wehrlitic system in order to constrain the petrogenesis of the crustal wehrlites of the Oman ophiolite. Secondary ion mass spectrometry analyses of clinopyroxenes from different wehrlite bodies imply that the clinopyroxenes were crystallized from tholeiitic, mid-ocean ridge (MORB)–type melts. The presence of primary magmatic amphiboles in some wehrlites suggests a formation under hydrous conditions. Significantly enhanced 87Sr/86Sr isotope ratios of separates from these amphiboles imply that the source of the corresponding magmatic fluids was either seawater or subduction zone–related. The experiments revealed that under wet conditions at relatively low temperatures, a MORB magma has the potential to produce wehrlite in the ocean crust by accumulation of early olivine and clinopyroxene. These show typically high Mg# which is a consequence of the oxidizing effect of the prevailing high aH2O. First plagioclases crystallizing after clinopyroxene under wet conditions are high in An content, in contrast to the corresponding dry system. Trace element compositions of clinopyroxenes of those wehrlites from the Moho transition zone are too depleted in HREE to be in equilibrium with present-day MORB, implying a genetic relation to the V2 lavas of the Oman ophiolite, which are interpreted to be the result of fluidenhanced melting of previously depleted mantle. We present a model on the petrogenesis of the crustal wehrlites in an upper mantle wedge above an initial, shallow subduction zone at the beginning of the
intraoceanic thrusting
Organising multi-dimensional biological image information: The BioImage Database
Nowadays it is possible to unravel complex information at all levels of cellular organization by obtaining multi-dimensional image information. at the macromolecular level, three-dimensional (3D) electron microscopy, together with other techniques, is able to reach resolutions at the nanometer or subnanometer level. The information is delivered in the form of 3D volumes containing samples of a given function, for example, the electron density distribution within a given macromolecule. The same situation happens at the cellular level with the new forms of light microscopy, particularly confocal microscopy, all of which produce biological 3D volume information. Furthermore, it is possible to record sequences of images over time (videos), as well as sequences of volumes, bringing key information on the dynamics of living biological systems. It is in this context that work on bioimage started two years ago, and that its first version is now presented here. In essence, Bioimage is a database specifically designed to contain multi-dimensional images, perform queries and interactively work with the resulting multi-dimensional information on the World Wide Web, as well as accomplish the required cross-database links. Two sister home pages of bioimage can be accessed at http://www.bioimage.org and http://www-embl.bioimage.or
2007 Guidelines for the management of arterial hypertension: The Task Force for the Management of Arterial Hypertension of the European Society of Hypertension (ESH) and of the European Society of Cardiology (ESC)
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Rapport préliminaire sur les activités de la mission archéologique franco-syrienne dans la micro-région d'Al-Rawda (Shamiyeh) : quatrième et cinquième campagnes (2005 et 2006)
This preliminary report presents the results of two campaigns of excavation and survey in 2005and 2006 on the site of AI-Rawda (West-Central Syria) and in the micro-region of 100 km2 around it. Thesite is a pre-planned circular new town. It was founded around 2400 BCE, in the steppe zone and was inhabitedonly during EB IV, until the end of the 3rd millennium. The work of 2005 and 2006 involved furtherextensive excavation of a sanctuary consisting of two temples and a temenos togeiher with aIl associatedinstallations (including a betyl in situ). The eastem gate of the town was excavated and four lines of defencehave been identified. A stratigraphie sounding in the southwest clarifies the origin of the town. In the necropolisassociated with the site, the excavation of a collective pit burial is presented. Intensive survey wascontinued outside the ancient town, with particular attention to sites that were occupied at the same time asAI-Rawda, to burials, which have been classified by type, and to installations that can be linked to agricultureor pastoralism. This work was supplemented by archaeobotanical, archaeozoological and geo-archaeologicalresearch, as weIl as a study of the environment.Ce rapport préliminaire présente les résultats de deux campagnes de fouilles et de prospection conduites en 2005 et 2006 sur le site d’Al-Rawda (Syrie du centre-ouest) et dans la microrégion de 100 km2 qui l’entoure. Le site, une ville neuve circulaire au plan d’urbanisme préconçu fondé vers 2500 av. J.-C., se trouve en zone steppique. Il n’est habité que durant le Bronze ancien IV, jusqu’à la fin du 3e millénaire.Les travaux en 2005 et 2006 ont porté sur la poursuite du dégagement extensif d’un sanctuaire qui regroupe deux temples et un temenos, avec l’ensemble des installations qu’ils contiennent (dont un bétyle in situ). À l’est, a été mise au jour la porte orientale de la ville tandis que quatre lignes de défense ont été identifiées. Un sondage stratigraphique au sud-ouest éclaire l’origine de la ville. Dans la nécropole associée au site, la fouille d’une tombe en puits collective est présentée.Parallèlement, la prospection intensive autour de la ville antique a été poursuivie en mettant l’accent sur les sites d’habitat contemporains d’Al-Rawda, les tombes caractérisées par type et les aménagements qui peuvent être liés à une mise en valeur agricole du territoire et au pastoralisme. Ces travaux ont été complétés par des études archéobotanique, archéozoologique, géoarchéologique et par une étude des milieux
The role of secretory leukocyte proteinase inhibitor and elafin (elastase-specific inhibitor/skin-derived antileukoprotease) as alarm antiproteinases in inflammatory lung disease
Secretory leukocyte proteinase inhibitor and elafin are two low-molecular-mass elastase inhibitors that are mainly synthesized locally at mucosal sites. It is thought that their physicochemical properties allow them to efficiently inhibit target enzymes, such as neutrophil elastase, released into the interstitium. Historically, in the lung, these inhibitors were first purified from secretions of patients with chronic obstructive pulmonary disease and cystic fibrosis. This suggested that they might be important in controlling excessive neutrophil elastase release in these pathologies. They are upregulated by 'alarm signals' such as bacterial lipopolysaccharides, and cytokines such as interleukin-1 and tumor necrosis factor and have been shown to be active against Gram-positive and Gram-negative bacteria, so that they have joined the growing list of antimicrobial 'defensin-like' peptides produced by the lung. Their site of synthesis and presumed functions make them very attractive candidates as potential therapeutic agents under conditions in which the excessive release of elastase by neutrophils might be detrimental. Because of its natural tropism for the lung, the use of adenovirus-mediated gene transfer is extremely promising in such applications
Hydrothermal cooling of the ocean crust: Insights from ODP Hole 1256D
publisher: Elsevier articletitle: Hydrothermal cooling of the ocean crust: Insights from ODP Hole 1256D journaltitle: Earth and Planetary Science Letters articlelink: http://dx.doi.org/10.1016/j.epsl.2017.01.010 content_type: article copyright: © 2017 The Author(s). Published by Elsevier B.V
Seismic reflection images of a near-axis melt sill within the lower crust at the Juan de Fuca ridge
Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature 460 (2009): 89-93, doi:10.1038/nature08095.The oceanic crust extends over two thirds of the Earth’s solid surface and is
generated along mid-ocean ridges from melts derived from the upwelling mantle.
The upper and mid crust are constructed by dyking and seafloor eruptions
originating from magma accumulated in mid-crustal lenses at the spreading axis,
but the style of accretion of the lower oceanic crust is actively debated. Models
based on geological and petrological data from ophiolites propose that the lower
oceanic crust is accreted from melt sills intruded at multiple levels between the
Moho transition zone (MTZ) and the mid-crustal lens, consistent with
geophysical studies that suggest the presence of melt within the lower crust.
However, seismic images of molten sills within the lower crust have been elusive.
To date only seismic reflections from mid-crustal melt lenses and sills within
the MTZ have been described, suggesting that melt is efficiently transported
through the lower crust. Here we report deep crustal seismic reflections off the
southern Juan de Fuca Ridge that we interpret as originating from a molten sill
presently accreting the lower oceanic crust. The sill sits 5-6 km beneath the
seafloor and 850-900 m above the MTZ, and it is located 1.4-3.2 km off thespreading axis. Our results provide evidence for the existence of low permeability
barriers to melt migration within the lower section of modern oceanic crust
forming at intermediate-to-fast spreading rates, as inferred from ophiolite
studies.This research was supported by grants form the US NSF
Residential greenspace and lung function decline over 20 years in a prospective cohort: the ECRHS study
Background The few studies that have examined associations between greenspace and lung function in adulthood have yielded conflicting results and none have examined whether the rate of lung function decline is affected. Objective We explored the association between residential greenspace and change in lung function over 20 years in 5559 adults from 22 centers in 11 countries participating in the population-based, international European Community Respiratory Health Survey. Methods Forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were measured by spirometry when participants were approximately 35 (1990–1994), 44 (1999–2003), and 55 (2010–2014) years old. Greenness was assessed as the mean Normalized Difference Vegetation Index (NDVI) in 500 m, 300 m, and 100 m circular buffers around the residential addresses at the time of lung function measurement. Green spaces were defined as the presence of agricultural, natural, or urban green spaces in a circular 300 m buffer. Associations of these greenspace parameters with the rate of lung function change were assessed using adjusted linear mixed effects regression models with random intercepts for subjects nested within centers. Sensitivity analyses considered air pollution exposures. Results A 0.2-increase (average interquartile range) in NDVI in the 500 m buffer was consistently associated with a faster decline in FVC (−1.25 mL/year [95% confidence interval: −2.18 to −0.33]). These associations were especially pronounced in females and those living in areas with low PM10 levels. We found no consistent associations with FEV1 and the FEV1/FVC ratio. Residing near forests or urban green spaces was associated with a faster decline in FEV1, while agricultural land and forests were related to a greater decline in FVC. Conclusions More residential greenspace was not associated with better lung function in middle-aged European adults. Instead, we observed slight but consistent declines in lung function parameters. The potentially detrimental association requires verification in future studies
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