177 research outputs found
Myself, man and manager
SIGLEAvailable from British Library Document Supply Centre-DSC:DXN041814 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
Localisation spatiale fine de ligneux en milieu forestier. Comment procéder de manière précise et dans les délais acceptables ?
Les bois des coteaux de Gascogne sont originaux : de taille réduite, souvent privés, morcelés et diversifiés, ils ont des rôles importants dans les territoires ruraux notamment comme refuge pour la biodiversité et source de revenu. Leur caractérisation est complexe, particulièrement pour la mise en évidence des relations entre la répartition spatiale des arbres et les autres facteurs de variations. Ceci implique de réaliser la cartographie des ligneux sur des surfaces variables, dans des conditions forestières denses donnant peu de visibilité. Les techniques existantes sont peu adaptées au milieu forestier et insuffisamment précises ; aussi nous travaillons depuis 4 ans dans plusieurs bois avec une technique alternative utilisant un télémètre laser, une boussole magnétique et un dendromètre à ultrasons qui répond à nos besoins en termes de précision et de faisabilit
Management of Hemophilia A in a Partial Hepatectomy
Presented as a poster at Indiana Society of Anesthesiologist
Counselling in substance misuse: a review of the literature.
This literature review will examine some of the more recent work on addiction counselling and psychotherapy with the aim of informing decision-making about optimum deployment of the Eastern Region Health Authority counselling resource
Predicting the vulnerability of seasonally-flooded wetlands to climate change across the Mediterranean Basin
Sélection de placettes forestières à l’échelle d’un territoire: complémentarité entre système d’information géographique et approches sur le terrain
Étudier le fonctionnement des écosystèmes requiert l’utilisation d’un échantillon suffisamment représentatif pour mettre en évidence des patrons généraux. Travailler à l’échelle d’un territoire de plusieurs milliers d’hectares devient alors intéressant mais coûteux en temps de préparation des placettes expérimentales in situ. Le système d’information géographique (SIG), de plus en plus utilisé en appui aux travaux menés en écologie, peut alors devenir un outil indispensable pour le travail en amont des relevés sur le terrain. A partir d’un cas d’étude où l’objectif expérimental était de sélectionner des placettes forestières selon quatre modalités écologiques, cet article présente la complémentarité entre l’utilisation d’un SIG et la prospection sur le terrain afin de minimiser les coûts de préparation de l’échantillon de placettes forestières souhaitées
Arterial Response to Shear Stress Critically Depends on Endothelial TRPV4 Expression
BACKGROUND: In blood vessels, the endothelium is a crucial signal transduction interface in control of vascular tone and blood pressure to ensure energy and oxygen supply according to the organs' needs. In response to vasoactive factors and to shear stress elicited by blood flow, the endothelium secretes vasodilating or vasocontracting autacoids, which adjust the contractile state of the smooth muscle. In endothelial sensing of shear stress, the osmo- and mechanosensitive Ca(2+)-permeable TRPV4 channel has been proposed to be candidate mechanosensor. Using TRPV4(-/-) mice, we now investigated whether the absence of endothelial TRPV4 alters shear-stress-induced arterial vasodilation. METHODOLOGY/PRINCIPAL FINDINGS: In TRPV4(-/-) mice, loss of the TRPV4 protein was confirmed by Western blot, immunohistochemistry and by in situ-patch-clamp techniques in carotid artery endothelial cells (CAEC). Endothelium-dependent vasodilation was determined by pressure myography in carotid arteries (CA) from TRPV4(-/-) mice and wild-type littermates (WT). In WT CAEC, TRPV4 currents could be elicited by TRPV4 activators 4alpha-phorbol-12,13-didecanoate (4alphaPDD), arachidonic acid (AA), and by hypotonic cell swelling (HTS). In striking contrast, in TRPV4(-/-) mice, 4alphaPDD did not produce currents and currents elicited by AA and HTS were significantly reduced. 4alphaPDD caused a robust and endothelium-dependent vasodilation in WT mice, again conspicuously absent in TRPV4(-/-) mice. Shear stress-induced vasodilation could readily be evoked in WT, but was completely eliminated in TRPV4(-/-) mice. In addition, flow/reperfusion-induced vasodilation was significantly reduced in TRPV4(-/-) vs. WT mice. Vasodilation in response to acetylcholine, vasoconstriction in response to phenylephrine, and passive mechanical compliance did not differ between genotypes, greatly underscoring the specificity of the above trpv4-dependent phenotype for physiologically relevant shear stress. CONCLUSIONS/SIGNIFICANCE: Genetically encoded loss-of-function of trpv4 results in a loss of shear stress-induced vasodilation, a response pattern critically dependent on endothelial TRPV4 expression. Thus, Ca(2+)-influx through endothelial TRPV4 channels is a molecular mechanism contributing significantly to endothelial mechanotransduction
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Expansion of Thaumarchaeota habitat range is correlated with horizontal transfer of ATPase operons.
Thaumarchaeota are responsible for a significant fraction of ammonia oxidation in the oceans and in soils that range from alkaline to acidic. However, the adaptive mechanisms underpinning their habitat expansion remain poorly understood. Here we show that expansion into acidic soils and the high pressures of the hadopelagic zone of the oceans is tightly linked to the acquisition of a variant of the energy-yielding ATPases via horizontal transfer. Whereas the ATPase genealogy of neutrophilic Thaumarchaeota is congruent with their organismal genealogy inferred from concatenated conserved proteins, a common clade of V-type ATPases unites phylogenetically distinct clades of acidophilic/acid-tolerant and piezophilic/piezotolerant species. A presumptive function of pumping cytoplasmic protons at low pH is consistent with the experimentally observed increased expression of the V-ATPase in an acid-tolerant thaumarchaeote at low pH. Consistently, heterologous expression of the thaumarchaeotal V-ATPase significantly increased the growth rate of E. coli at low pH. Its adaptive significance to growth in ocean trenches may relate to pressure-related changes in membrane structure in which this complex molecular machine must function. Together, our findings reveal that the habitat expansion of Thaumarchaeota is tightly correlated with extensive horizontal transfer of atp operons
Gravitational Energy Loss and Binary Pulsars in the Scalar Ether-Theory of Gravitation
Motivation is given for trying a theory of gravity with a preferred reference
frame (``ether'' for short). One such theory is summarized, that is a scalar
bimetric theory. Dynamics is governed by an extension of Newton's second law.
In the static case, geodesic motion is recovered together with Newton's
attraction field. In the static spherical case, Schwarzschild's metric is got.
An asymptotic scheme of post-Minkowskian (PM) approximation is built by
associating a conceptual family of systems with the given weakly-gravitating
system. It is more general than the post-Newtonian scheme in that the velocity
may be comparable with . This allows to justify why the 0PM approximation of
the energy rate may be equated to the rate of the Newtonian energy, as is
usually done. At the 0PM approximation of this theory, an isolated system loses
energy by quadrupole radiation, without any monopole or dipole term. It seems
plausible that the observations on binary pulsars (the pulse data) could be
nicely fitted with a timing model based on this theory.Comment: Text of a talk given at the 4th Conf. on Physics Beyond the Standard
Model, Tegernsee, June 2003, submitted to the Proceedings (H. V.
Klapdor-Kleingrothaus, ed.
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