2,439 research outputs found

    Oscillatory behavior of the bed bulk and the bubbles in a vertically vibrated pseudo-2D bed in bubbling regime

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    The effect of the bed vessel vibration on the oscillatory behavior of the bed bulk and the bubbles is experimentally studied in the present work by means of Digital Image Analysis (DIA) in a pseudo-2D bed. The bed material was three different powders of Geldart A, B and AFB classifications and was operated in bubbling regime for different superficial gas velocities and vibration amplitudes and frequencies. A tracking methodology was developed in order to follow the oscillatory motion of the bed bulk and each individual bubble in the system. This allowed the analysis of the interaction of the dense phase of the bed with the oscillations of the Nibble diameter, position and velocity. The results indicate that both the center of mass of the bed and the bubble characteristics follow the oscillation of the bed vessel with a similar frequency but with a phase delay. The amplitude and phase delay of the oscillation of the center of mass of the bed are more sensitive to variations of the vibration frequency than to variations of the vibration amplitude of the bed vessel. Both the amplitude and the frequency of the bed vessel vibration have a stronger impact on the bubble behavior of beds filled with small particles. The existence of a phase delay between the oscillations of bubble characteristics in the lower and upper sections of the bed indicates the existence of compression-expansion waves in the dense phase that modify the bubble behavior along the bed despite bubbles are interacting with each other. The presence of compression-expansion waves may shed light onto the different behaviors encountered for the mean bubble behavior in vibrated fluidized beds.This work has been partially funded by the Universidad Carlos III de Madrid, Ayudas a la Movilidad 2014

    Overexpression of AtGRDP2, a novel glycine-rich domain protein, accelerates plant growth and improves stress tolerance

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    "Proteins with glycine-rich signatures have been reported in a wide variety of organisms including plants, mammalians, fungi, and bacteria. Plant glycine-rich protein genes exhibit developmental and tissue-specific expression patterns. Herein, we present the characterization of the AtGRDP2 gene using Arabidopsis null and knockdown mutants and, Arabidopsis and lettuce over-expression lines. AtGRDP2 encodes a short glycine-rich domain protein, containing a DUF1399 domain and a putative RNA recognition motif (RRM). AtGRDP2 transcript is mainly expressed in Arabidopsis floral organs, and its deregulation in Arabidopsis Atgrdp2 mutants and 35S::AtGRDP2 over-expression lines produces alterations in development. The 35S::AtGRDP2 over-expression lines grow faster than the WT, while the Atgrdp2 mutants have a delay in growth and development. The over-expression lines accumulate higher levels of indole-3-acetic acid and, have alterations in the expression pattern of ARF6, ARF8, and miR167 regulators of floral development and auxin signaling. Under salt stress conditions, 35S::AtGRDP2 over-expression lines displayed higher tolerance and increased expression of stress marker genes. Likewise, transgenic lettuce plants over-expressing the AtGRDP2 gene manifest increased growth rate and early flowering time. Our data reveal an important role for AtGRDP2 in Arabidopsis development and stress response, and suggest a connection between AtGRDP2 and auxin signaling.

    Diez años de innovación docente en Filología Clásica en la Comunidad Autónoma de Madrid (I)

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    Los últimos años han sido muy fructíferos en iniciativas oficiales de innovación y mejora de la calidad docente en el ámbito de la Comunidad de Madrid. Tanto en la Universidad, a través de los PIMCD (o análogos), como en los TMFP del ICE (o análogos), como en enseñanza secundaria, se han puesto en marcha diferentes iniciativas y proyectos con el objetivo de mejorar la docencia y la recepción por parte de los estudiantes de las materias relacionadas con el riquísimo legado cultural de Grecia y Roma. La Sociedad Española de Estudios Clásicos ha sido también una institución promotora a través de la convocatoria de premios anuales que reconocen el trabajo de los docentes y estudiantes de estas materias. Sin embargo, a pesar de lo mucho y bueno realizado, se echa en falta una labor que recabe toda la información dispersa, la estructure y organice y, sobre todo, la ponga a disposición, cuando ello sea posible, de los docentes y estudiantes. Por otra parte, los filólogos clásicos se han incorporado de lleno a la profunda renovación metodológica que ha supuesto la irrupción de las TICS en el ámbito docente, sustituyendo las antiguas metodologías basadas en la repetición por otras mucho más dinámicas y polivalentes. Nuestra tarea se restringe a los últimos diez años, los más prolíficos desde el punto de vista de la innovación en Clásicas, sin que ello sea obstáculo para que en convocatorias posteriores ampliemos nuestro abanico cronológico y geográfico

    Assessing sea grass meadows condition at “El Río” Special Area of Conservation off “La Graciosa e Islotes del Norte de Lanzarote” Marine Reserve

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    Cymodosea nodosa meadows, known as ‘sebadales’ or ‘manchones’ at Canary Islands, represent EUNIS habitat type code A5.5311, called Macaronesian Cymodocea beds. As it’s described at European Union Habitats Directive (92/43/CEE) Annex 1, sea grass meadows belong to 1110 Sandbanks which are slightly covered by seawater all the time, within Natura 2000 Network. Several ‘sebadales’ throughout the archipelago are included in this Network as Special Areas of Conservation. Cymodosea nodosa is regionally included within the Canary Islands Protected Species List (Ley 4/2010), as a species ‘of interest to ecosystems of Canary Islands”, is usually found at a narrow depth range (10 to 20 m of depth) and, on the whole, best structured meadows are settled at sheltered bays, away from wave and current beating, flimsier at exposed areas. Deeper meadows are also sparser, being C. nodosa replaced by green algae Caulerpa prolifera and Caulerpa racemosa, although mixed algae-sea grass meadows are often found at different depths. The project Assessment of marine flora (‘sebadal’, ma¨erl, ‘mujo’) of ‘La Graciosa e Islotes del Norte de Lanzarote’ Marine Reserve, funded by ‘Viceconsejer´ıa de Pesca y Aguas de la Consejer´ıa de Agricultura, Ganader´ıa, Pesca y Aguas’, Canary Islands Government, has had the aim of assessing sea grass meadows condition and distribution at ‘El R´ıo’ Natura 2000 Network Special Area of Conservation, the channel between La Graciosa and Lanzarote. ‘LA GRACIOSA 1311’ cruise was performed within the framework of the project. First of all previous information on sea grass shallow distribution (up to a depth of 20 m) in the study area was reviewed. Afterwards, a tugged underwater video camera was used onboard of the Marine Reserve Surveillance Vessel to update cartographic info performing a grid of sampling stations, covering previously known distribution limits and verifying current presence/absence data and density. Furthermore, population parameters were obtained in order to assess ‘sebadal’ condition. Fixed stations were selected in regards to this process, and methodology applied on them was as follows: five radial arranged transects were performed, identifying fragmentation (it estimates meadow continuity regarding observed cover), density (mean value of several shoots number counts with 20 x 20 cm grids placed every 2 m), height (mean value in cm of 10 independent samples by transect) and fish and macroinvertebrate species richness for each transect. Graphic picture of sea grass density was made depending on two levels: low density level transects ( 10 shoots/grid ( 50 shoots/m2) and medium density level transects ( 10 shoots/grid ( 50 shoots/m2). Main study result is an estimate for the study region (‘El R´ıo’) and time of year of Cymodocea nodosa population total distribution cover which comes to 1.640.076 m2, including a higher density ‘sebadal’ of 178.256 m2

    Sofosbuvir improves HCV-induced insulin resistance by blocking IRS1 degradation

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    In the present study, we have demonstrated that sofos buvir (SOF) treatment improves systemic insulin resis tance in hepatitis C virus (HCV)-patients, and, for the first time, revealed which molecular mechanisms are involved in SOF effects on the impaired insulin response induced by HCV in hepatocytes

    Evaluación de la toxicidad del Vitrofural® en agar sobre lombriz de tierra

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    Vitrofural® is an additive used for the chemical sterilization of plant culture media in the in vitro propagation of plants. At the end of its use, it becomes a waste of the biotechnological process and is dumped into confined terrestrial environments. Nevertheless, the possible ecotoxicological impacts that could occur are unknown. The aim of this work was to determine the acute toxicity of earthworms (Eisenia foetida) by exposure to Vitrofural® residues on agar. The toxic potential of the waste was evaluated by single exposure to earthworms for 14 days. Worms were exposed by contact and ingestion at a concentration corresponding to the maximum possible to be obtained from lixiviate of the solid residue of Vitrofural® on agar, after 7 and 21 days of preparation. The number of dead animals and the loss of body mass were quantified, and the sublethal toxic signs were described. In the experimental groups there was no mortality, only slight morphological and physiological alterations were observed with a tendency to decrease in frequency in the group exposed to the lixiviates with 21 days of preparation. Similar response was observed in the evolution of body mass. The lixiviated of Vitrofural® in agarized medium induce slight sublethal effects in earthworms a function of the preparation time and demonstrate the absence of ecotoxicological risk due to exposure in this specie.Keywords: bioassay, chemical sterilization, Eisenia foetida, toxicityEl Vitrofural® es un aditivo utilizado para la esterilización química de los medios de cultivo en la propagación in vitro de plantas. Al término de su utilización se convierte en un desecho del proceso biotecnológico y es vertido a ambientes terrestres confinados. Sin embargo, se desconocen los posibles impactos ecotoxicológicos que pudiera producir. El objetivo de este trabajo fue determinar la toxicidad aguda sobre lombrices de tierra (Eisenia foetida) por exposición a los residuos del Vitrofural® en agar. Se evaluó el potencial tóxico de los residuos por exposición única a lombrices de tierra durante 14 días. Se expusieron lombrices por contacto e ingestión a una concentración que se corresponde con la máxima posible a obtener del lixiviado del residuo sólido del Vitrofural® en agar, después de 7 y 21 días de preparado. El número de animales muertos y la pérdida de masa corporal se cuantificaron y se describieron los signos tóxicos subletales. En los grupos experimentales no ocurrió mortalidad, solo se presentaron ligeras alteraciones morfológicas y fisiológicas no significativas con tendencia a disminuir en frecuencia en el grupo expuesto al lixiviado con 21 días de preparado. Similar respuesta fue observada en la evolución de la masa corporal. Los lixiviados del Vitrofural® en medio agarizado inducen ligeros efectos subletales en lombrices de tierra en función del tiempo de preparado y demuestran la ausencia de riesgo ecotoxicológico por exposición en dicha especie. Palabras clave: bioensayo, Eisenia foetida, esterilización química, toxicida

    Effects of the anthropogenics pressures (marine litter) on the coastal ecosystems of the Marine Reserve “Isla de La Graciosa e islotes del norte de Lanzarote”

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    The European Marine Strategy Framework Directive (2008/56/EC) considers marine litter as one of its environmental descriptors, requiring the development and standardization of criteria and methodologies for its use to test the good environmental status of marine conditions. The assessment of the impact caused by litter accumulation in the shoreline lacked specific monitoring planning and had not been systematically performed to date in Canary Islands. During the project ”Evaluation of the effect of the anthropogenic pressures (marine litter in beaches and alteration of shallow seabed by boats anchoring) on the coastal ecosystems of the “Marine Reserve of Isla de La Graciosa e islotes del norte de Lanzarote (MRLG)” developed with the financial help of the Canary Islands Government (Council of Agriculture, Ranching, Fishing and Waters), two surveys were carried out, ”LA GRACIOSA 1310” and “LA GRACIOSA 1311”, both developed at MRLG and its vicinities. The aim has been to depict MRLG shoreline and to locate marine litter accumulation points the most, contributing with some tools to assess and manage the coastal ecosystems of the marine reserve. Total shoreline sampled at both surveys together was 38326 m, 1834 m at Alegranza, 1366 m at Monta˜na Clara, 24656 m at La Graciosa Island, and the rest, 10470 m, at the Lanzarote’s shoreline portion bathed by MRLG waters. Shoreline sampling was made qualitatively sorting the sampling stations, according to litter presence and distribution, by means of a upward numerical coding related to the type of waste or garbage found. Moreover, each station was additionally depicted according to the type of substrate as well as to the prevailing type of waste, defining what we named “transects”. To validate methodology to European standards, a more exhaustive experimental sampling was made in four transects identified as high density or high concentration of marine litter, following guidelines of a method developed for OSPAR maritime area during the first half of 2000 decade (OSPAR, 2007). It involves evaluating the possibilities and needs of adjustment of this methodology to the particular conditions of our region (Gonz´alez, et al., 2013 a and b). As preliminary results, the spatial distribution of garbage coastal accumulation will be shown in a cartographic base, expressed as relative abundance by island, according to a 4 degrees scale (no litter, low, medium and high litter presence) and according to the dominant kind of garbage in each transect. An example with one of the most densely occupied with trash transects is shown to illustrate a sampling method without the requirement of trash collection. This method uses a sampling unit of 1x1 m grid, divided in 10x10 cm subgrids. This grid is set parallel to sampling direction repeatedly. Distance between grids is determined by a randomizing software. Sampling direction zigzags from sea border to beach back shore, making 45° degrees angles. Subgrids occupied by trash are counted once the grid is set. Waste is depict and identified following a guide developed for this purpose by OSPAR in 2010

    Signatures of a two-dimensional ferromagnetic electron gas at the La_(0.7)Sr_(0.3)MnO_(3)/SrTiO_(3) interface arising from orbital reconstruction

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    The magnetoresistance of La0.7Sr0.3MnO3/SrTiO3La0.7Sr0.3MnO3/SrTiO3 superlattices with magnetic field rotating out-of-plane shows unexpected peaks for in-plane fields. Resistivity calculations with spin–orbit coupling reveal that orbital reconstruction at the manganite interface leads to a 2D ferromagnetic electron gas coupled antiparallel to the manganite “bulk”. These orbital and magnetic reconstructions are supported by X-ray linear dichroism and ab initio calculations

    Millimeter and submillimeter high angular resolution interferometric observations: dust in the heart of IRAS 18162-2048

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    The GGD27 complex includes the HH 80-81-80N system, which is one of the most powerful molecular outflows associated with a high mass star-forming region observed up to now. This outflow is powered by the star associated with the source IRAS 18162-2048. Here we report the detection of continuum emission at sub-arcsec/arcsec resolution with the Submillimeter Array at 1.36mm and 456microns, respectively. We detected dust emission arising from two compact cores, MM1 and MM2, separated by about 7" (~12000AU in projected distance). MM1 spatially coincides with the powerful thermal radio continuum jet that powers the very extended molecular outflow, while MM2 is associated with the protostar that drives the compact molecular outflow recently found in this region. High angular resolution obervations at 1.36mm show that MM1 is unresolved and that MM2 splits into two subcomponents separated by ~1". The mass of MM1 is about 4Msun and it has a size of <300AU. This is consistent with MM1 being associated with a massive and dense (n(H2)>10^9cm-3) circumstellar dusty disk surrounding a high-mass protostar, which has not developed yet a compact HII region. On the other hand, the masses of the two separate components of MM2 are about 2Msun each. One of these components is a compact core with an intermediate-mass young protostar inside and the other component is probably a pre-stellar core. MM1 is the brigthest source at 1.36mm, while MM2 dominates the emission at 456microns. These are the only (sub)millimeter sources detected in the SMA observations. Hence, it seems that both sources may contribute significantly to the bolometric luminosity of the region. Finally, we argue that the characteristics of these two sources indicate that MM2 is probably in an earlier evolutionary stage than MM1.Comment: Accepted in AJ (Oct 31, 2010

    A rotating molecular disk toward IRAS 18162-2048, the exciting source of HH 80-81

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    We present several molecular line emission arcsec and subarcsec observations obtained with the Submillimeter Array (SMA) in the direction of the massive protostar IRAS 18162-2048, the exciting source of HH 80-81. The data clearly indicates the presence of a compact (radius~425-850 AU) SO2 structure, enveloping the more compact (radius~150 AU) 1.4 millimeter dust emission (reported in a previous paper). The emission spatially coincides with the position of the prominent thermal radio jet which terminates at the HH 80-81 and HH 80N Herbig-Haro objects. Furthermore, the molecular emission is elongated in the direction perpendicular to the axis of the thermal radio jet, suggesting a disk-like structure. We derive a total dynamic mass (disk-like structure and protostar) of 11-15 msun. The SO2 spectral line data also allow us to constrain the structure temperature between 120-160 K and the volume density > 2x10^9 cm-3. We also find that such a rotating flattened system could be unstable due to gravitational disturbances. The data from C17O line emission show a dense core within this star-forming region. Additionally, the H2CO and the SO emissions appear clumpy and trace the disk-like structure, a possible interaction between a molecular core and the outflows, and in part, the cavity walls excavated by the thermal radio jet.Comment: 13 pages,11 figures. Accepted in the AJ, 07-15-201
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