Estimates for functions of the Laplacian on manifolds with bounded geometry

In this paper we consider a complete connected noncompact Riemannian manifold M with Ricci curvature bounded from below and positive injectivity radius. Denote by L the Laplace-Beltrami operator on M. We assume that the kernel associated to the heat semigroup generated by L satisfies a mild decay condition at infinity. We prove that if m is a bounded holomorphic function in a suitable strip of the complex plane, and satisfies Mihlin-Hormander type conditions of appropriate order at infinity, then the operator m(L) extends to an operator of weak type 1. This partially extends a celebrated result of J. Cheeger, M. Gromov and M. Taylor, who proved similar results under much stronger curvature assumptions on M, but without any assumption on the decay of the heat kernel.Comment: 19 page

Higher order Riesz transforms on noncompact symmetric spaces

In this note we prove various sharp boundedness results on suitable Hardy type spaces for Riesz transforms of arbitrary order on noncompact symmetric spaces of arbitrary rank.Comment: v2: the first version has been revised and splitted up in two papers, of which this new version is one par

A family of Hardy-type spaces on nondoubling manifolds

We introduce a decreasing one-parameter family Xγ(M) , γ> 0 , of Banach subspaces of the Hardy–Goldberg space h1(M) on certain nondoubling Riemannian manifolds with bounded geometry, and we investigate their properties. In particular, we prove that X1 / 2(M) agrees with the space of all functions in h1(M) whose Riesz transform is in L1(M) , and we obtain the surprising result that this space does not admit an atomic decomposition

Maximal characterisation of local Hardy spaces on locally doubling manifolds

We prove a radial maximal function characterisation of the local atomic Hardy space h1(M) on a Riemannian manifold M with positive injectivity radius and Ricci curvature bounded from below. As a consequence, we show that an integrable function belongs to h1(M) if and only if either its local heat maximal function or its local Poisson maximal function is integrable. A key ingredient is a decomposition of Hölder cut-offs in terms of an appropriate class of approximations of the identity, which we obtain on arbitrary Ahlfors-regular metric measure spaces and generalises a previous result of A. Uchiyama

Protoariciella uncinata Hartmann-Schröeder, 1962 (Polychaeta, Orbiniidae): a new record for intertidal mussel beds of the Southwestern Atlantic shore affected by sewage effluents

Protoariciella uncinata (Polychaeta, Orbiniidae) is mentioned for the first time in southwestern Atlantic shores, from mytilid mussel beds of Brachidontes rodriguezi of the Mar del Plata area, Argentine. The species was formely described for mytilids banks of the Pacific coast of Chile and Peru. The work also provides information about spatial distribution, relationship with sewage organic enrichment, density and other ecological data.La especie Protoariciella uncinata (Polychaeta, Orbiniidae) es mencionada por primera vez para el Atlántico sudoccidental, proveniente de muestreos intermareales realizados en la comunidad del mitílido Brachidontes rodriguezi del área de Mar del Plata, Argentina. La especie ha sido anteriormente citada para bancos de mitílidos de Chile y Perú. El trabajo también brinda información sobre distribución espacial, relación con el gradiente orgánico producido por efluentes cloacales, densidad y otros datos ecológicos

Perturbaciones debidas a efluentes domésticos en poliquetos asociados a bancos de bivalvos de Brachidontes rodriguezii en Mar de Plata (Atlántico sudoccidental)

Continuous and short-term disturbances are produced on intertidal Brachidontes rodriguezii mussel beds by the sewage outfall of Mar del Plata, SW Atlantic. The effects on the associated polychaetes living on and between mussels were investigated, in both the spatial and short-term temporal scales. Multivariate methods show that the polychaete fauna was influenced by tidal level, total amount of sediment accumulated between mussels, distance from the sewage outfall, organic carbon of interstitial sediments, and sewage volume before and after the summer season. Environmental variables in the water column fitted with a spatial and temporal organic gradient. Capitella ‘capitata’ sp. showed typical opportunistic behaviour in relation to organic enrichment, as did Neanthes succinea, both being numerically dominant near the sewage discharge. Cirratulus sp., Caulleriella alata, and Boccardia polybranchia were common at intermediate distances from the outfall. Syllis prolixa, S. gracilis, and Protoariciella uncinata reached their highest abundance at intermediate stations and were characteristic of the control site. Close to the outfall mussel density and dominance is low, and opportunist polychaetes successfully colonize organically enriched interstitial sediments. At intermediate distances from the outfall sediments retained by mussels reach their maximum values, and density of polychaetes is also high. The control station is characterized by monolayered mussel beds and very low diversity of polychaetes. Opportunistic polychaetes increase in response to short-term increases of sewage discharge during the summer season (November-March).Perturbaciones contínuas y de corto período de tiempo debidas a efluentes domésticos afectan a los bancos de los bivalvos Brachidontes rodriguezii en Mar del Plata, Atlántico sudoccidental. Se investigaron sus efectos sobre los poliquetos que viven asociados dentro y sobre los bancos, tanto en la escala espacial como la temporal (corto plazo). Métodos multivariados mostraron que los poliquetos estuvieron relacionados al nivel de marea, al total de sedimentos acumulados entre los bivalvos, a la distancia al efluente, al carbono orgánico total de los sedimentos y al volumen de descarga antes y después del verano. Las variables ambientales de la columna de agua estuvieron en concordancia con un gradiente de enriquecimiento orgánico espacial y temporal. Capitella ‘capitata’ sp. mostró el típico comportamiento oportunista en relación al enriquecimiento orgánico, al igual que Neanthes succinea, siendo ambas especies numéricamente dominantes cerca del efluente. Cirratulus sp., Caulleriella alata y Boccardia polybranchia fueron comunes a distancias intermedias del efluente. Syllis prolixa, S. gracilis y Protoariciella uncinata alcanzaron sus más altas abundancias a distancias intermedias, pero fueron características del sitio control. Cerca de la descarga del efluente la densidad y dominancia de bivalvos es baja, y los poliquetos oportunistas colonizaron exitosamente los sedimentos intersticiales enriquecidos orgánicamente. A distancias intermedias del efluente los sedimentos retenidos por los bivalvos alcanzaron sus mayores valores, y la riqueza de los poliquetos fue también alta. Las áreas control estuvieron caracterizadas por una monocapa de bivalvos y muy baja riqueza de poliquetos. Los poliquetos oportunistas incrementaron sus abundancias en respuesta al incremento del volumen de descarga en el período antes-después del verano (noviembre-marzo). &nbsp

Alteration of the interconversion of pyruvate and malate in the plastid or cytosol of ripening tomato fruit invokes diverse consequences on sugar but similar effects on cellular organic Acid, metabolism, and transitory starch accumulation

The aim of this work was to investigate the effect of decreased cytosolic phosphoenolpyruvate carboxykinase (PEPCK) and plastidic NADP-dependent malic enzyme (NADP-ME) on tomato (Solanum lycopersicum) ripening. Transgenic tomato plants with strongly reduced levels of PEPCK and plastidic NADP-ME were generated by RNA interference gene silencing under the control of a ripening-specific E8 promoter. While these genetic modifications had relatively little effect on the total fruit yield and size, they had strong effects in fruit metabolism. Both transformants were characterized by lower levels of starch at breaker stage. Analysis of the activation state of ADP-glucose pyrophosphorylase correlated with the decrease of starch in both transformats, which suggest that is due to an altered cellular redox status. Moreover, metabolic profiling and feeding experiments involving positional labelled glucoses of fruits lacking in plastidic NADP-malic enzyme and cytosolic PEPCK activities revealed differential changes in overall respiration rates and tricarboxylic acid (TCA) cycle flux. Inactivation of cytosolic PEPCK affected the respiration rate which suggests that excess of oxaloacetate OAA is converted to aspartate and reintroduced in the TCA via 2-oxoglutarate/glutamate. On the other hand, the plastidic NADP-malic enzyme antisense lines were characterized by no changes in respiration rates and TCA cycle flux and together with an increase of pyruvate kinase and phosphoenolpyruvate carboxylase activities indicates that pyruvate is supply through these enzymes to the TCA cycle. These results are discussed in the context of current models of the importance of malate during tomato fruit ripening