The first INTEGRAL-OMC catalogue of optically variable sources

The Optical Monitoring Camera (OMC) onboard INTEGRAL provides photometry in the Johnson V-band. With an aperture of 50 mm and a field of view of 5deg x 5deg, OMC is able to detect optical sources brighter than V~18, from a previously selected list of potential targets of interest. After more than nine years of observations, the OMC database contains light curves for more than 70000 sources (with more than 50 photometric points each). The objectives of this work have been to characterize the potential variability of the objects monitored by OMC, to identify periodic sources and to compute their periods, taking advantage of the stability and long monitoring time of the OMC. To detect potential variability, we have performed a chi-squared test, finding 5263 variable sources out of an initial sample of 6071 objects with good photometric quality and more than 300 data points each. We have studied the periodicity of these sources using a method based on the phase dispersion minimization technique, optimized to handle light curves with very different shapes.In this first catalogue of variable sources observed by OMC, we provide for each object the median of the visual magnitude, the magnitude at maximum and minimum brightness in the light curve during the window of observations, the period, when found, as well as the complete intrinsic and period-folded light curves, together with some additional ancillary data.Comment: Accepted by Astronomy & Astrophysics; 13 pages, 16 figures. Figures' resolution has been degraded to fit astro-ph constraint

Chirality in Bare and Passivated Gold Nanoclusters

Chiral structures have been found as the lowest-energy isomers of bare (Au$_{28}$ and Au$_{55}) and thiol-passivated (Au$_{28}(SCH$_{3})$_{16}$and Au$_{38}(SCH_{3})_{24}) gold nanoclusters. The degree of chirality existing in the chiral clusters was calculated using the Hausdorff chirality measure. We found that the index of chirality is higher in the passivated clusters and decreases with the cluster size. These results are consistent with the observed chiroptical activity recently reported for glutahione-passivated gold nanoclusters, and provide theoretical support for the existence of chirality in these novel compounds.Comment: 5 pages, 1 figure. Submitted to PR

Parallel implementation for large and sparse eigenproblems

This paper analyses and evaluates the computational aspects of an efficient parallel implementation for the eigenproblem. This parallel implementation allows to solve the eigenproblem of symmetric, sparse and very large matrices. Mathematically, the algorithm is supported by the Lanczos and Divide and Conquer methods. The Lanczos method transforms the eigenproblem of a symmetric matrix into an eigenproblem of a tridiagonal matrix which is easier to be solved. The Divide and Conquer method provides the solution for the eigenproblem of a large tridiagonal matrix by decomposing it in a set of smaller subproblems. The method has been implemented for a distributed memory multiprocessor system with the PVM parallel interface. A Cray T3E system with up to 32 nodes has been used to evaluate the performance of our parallel implementation. Due to the super-lineal speed-up values obtained for all the studied matrices, a detailed analysis of the experimental results is carried out. It will be shown that the management of the memory hierarchy plays an important role in the performance of the parallel implementation

Frizzled-8 integrates Wnt-11 and transforming growth factor-β signaling in prostate cancer

Wnt-11 promotes cancer cell migration and invasion independently of β-catenin but the receptors involved remain unknown. Here, we provide evidence that FZD8 is a major Wnt-11 receptor in prostate cancer that integrates Wnt-11 and TGF-β signals to promote EMT. FZD8 mRNA is upregulated in multiple prostate cancer datasets and in metastatic cancer cell lines in vitro and in vivo. Analysis of patient samples reveals increased levels of FZD8 in cancer, correlating with Wnt-11. FZD8 co-localizes and co-immunoprecipitates with Wnt-11 and potentiates Wnt-11 activation of ATF2-dependent transcription. FZD8 silencing reduces prostate cancer cell migration, invasion, three-dimensional (3D) organotypic cell growth, expression of EMT-related genes, and TGF-β/Smad-dependent signaling. Mechanistically, FZD8 forms a TGF-β-regulated complex with TGF-β receptors that is mediated by the extracellular domains of FZD8 and TGFBR1. Targeting FZD8 may therefore inhibit aberrant activation of both Wnt and TGF-β signals in prostate cancer

Predictive modelling of magnesium concentration in grapevine petioles as a basis for liming recommendations in vineyard acid soils

Soil acidification is a natural process which can either be accelerated by the activity of plants, animals and humans, but can be controlled through appropriate soil management. The main aim of this work was to develop a predictive modelling of magnesium concentration in grapevine petioles for liming amendment recommendation in vineyard acid soils. One liming material, dolomite, has been added to the soil at three doses: 0.9, 1.8 and 2.7 t CaCO3 ha-1. Magnesium exchangeable content in soil surface and concentrations of this nutrient in petioles of leaf samples were investigated during three years. Exchangeable magnesium in soil tended to increase with increasing dolomite application rate. These increases were significant among all the doses and the control, except for the dose of 0.9. However, only between the highest dose and the control significant differences in magnesium concentration in petioles could be detected. In addition, one linear model has been proposed to make liming recommendations in vineyard acid soils based on petiole magnesium concentrations.

Procedimiento de obtención de un material cerámico de forsterita

Procedimiento de obtención de un material cerámico de forsterita. Procedimiento de obtención de un material cerámico a partir de un silicato laminar hidroxilado, preferiblemente talco, que comprende: mezclar una suspensión acuosa de silicato laminar hidroxilado con óxido de magnesio; secar la suspensión obtenida anteriormente a una temperatura de hasta 350ºC; y tratar térmicamente el producto secado a una temperatura de hasta 1600ºC. Además, la invención se refiere a un material cerámico obtenible por el procedimiento descrito que comprende forsterita en una proporción de entre un 70% y un 95% en peso del material cerámico, y a sus aplicaciones como material refractario o como material electrocerámico.Peer reviewedConsejo Superior de Investigaciones ientifícas (España), Universidad de Sevilla, Universidad de AlmeríaA1 Solicitud de patente con informe sobre el estado de la técnic

Nueva localidad de anidación de la garza agami, Agamia agami (Pelecaniformes: Ardeidae) en Ecuador

The Agami heron, Agamia agami, is a rare species of the Neotropics, and even though its distribution is large, little is known about the sites where it congregates to nest. We report a new nesting site, which is the eighth reported site in the Neotropics, located in Tambococha, Yasuní National Park, Ecuador. We estimate that it is occupied by approximately 140 individuals, based on the 70 nests counted and considering the monogamous behavior of this species for at least one year. The discovery of this nesting colony is important to determine more precisely the distribution area of this species, and, in the future, monitor populations and develop studies of population genetics, migration, and behavioral movements as a basis to implement a conservation strategy for the Agami Heron in Ecuador.La garza Agamia agami es una especie rara que habita en el Neotrópico. Aunque su distribución es amplia, se sabe poco sobre los sitios donde se congrega para anidar. Reportamos un nuevo sitio de anidación, el octavo conocido en el Neotropico, ubicado en Tambococha, Parque Nacional Yasuní, Ecuador. Estimamos la presencia de aproximadamente 140 individuos, cifra que se basa en los 70 nidos contabilizados, considerando el comportamiento monógamo que presenta esta especie por lo menos en un año. El descubrimiento de esta colonia de anidación es importante para determinar con mayor precisión el área de distribución de esta especie y, en el futuro, realizar estudios genéticos poblacionales, movimientos migratorios, comportamentales y de monitoreo que sirvan de base para implementar una estrategia de conservación de la garza agami en Ecuador

Secondary homotopy groups

Secondary homotopy groups supplement the structure of classical homotopy groups. They yield a track functor on the track category of pointed spaces compatible with fiber sequences, suspensions and loop spaces. They also yield algebraic models of homotopy types with homotopy groups concentrated in two consecutive dimensions.Comment: We added further commets and references to make the paper more easily readabl