The possibility of a Sisterhood Myth

We will analyse a mythical scene between two female figurations: Baubo and Demeter. Our interest is to rescue a narrative of female alliance from the stories of rivalry between goddesses and between these and women, and from the stories if brotherhood between male figurations. This myth allows us to rebuild the image of a safe space for women, a place in which to share life and death, pain and joy. To achieve our goal, we will turn to the original sources as well as contemporary reflections on this myth. We will go on to analyse the elements that make up the narrative, developing the implications that  the could have for women in order to offer a general interpretation that leads us to extract considerations about the possibility of a genuine alliance between women.En las siguientes líneas analizaremos la escena mítica que ocurre entre dos figuraciones femeninas, a saber: Baubo y Deméter. Nuestro interés en señalar dicha escena responde a rescatar una narración de alianza femenina frente a los relatos de rivalidad entre diosas y entre estas y mujeres y, también, frente a los relatos de fraternidad entre figuraciones masculinas.  Rescatar este mito nos permite reconstruir la imagen de un espacio seguro para mujeres, un lugar en el que compartir vida y muerte, dolor y alegría. Para ello recurriremos a las fuentes originales que nos transmiten esta escena, así como a reflexiones contemporáneas sobre este mito. Pasaremos a analizar los elementos que configuran la narración desarrollando la implicaciones que podrían tener para las mujeres con el objetivo de poder ofrecer una interpretación general que nos lleve a extraer una serie de consideraciones acerca de la posibilidad de una alianza genuina entre mujeres

Habitando el entre: Estética, Literatura y Psicoanálisis en Sarah Kofman

En la presente investigación aportamos una primera aproximación en castellano al pensamiento de Sarah Kofman a partir de tres ejes o disciplinas que configuran el tejido textual de nuestra autora, a saber: la estética, la literatura y el psicoanálisis. Sin embargo, no serán nuestros temas de estudio, ya que en nuestro trabajo se articulan como las vías de abordaje de un vastísimo pensamiento. Lo que aquí exponemos trata, entonces, de proponer una exposición crítica, fiel y rigurosa de los textos de Kofman, que nos ayudarán a construir el «habitando el entre», la ambivalencia; lo que apunta a un devenir en la multiplicidad y en la diferencia. Esta formulación remite a ese tejido que conforma Kofman a través de su biografía y de su obra, en el que se vinculan los elementos como coordenadas que nos permiten acercarnos a su pensamiento..

Comparación temporal de la estructura de dos comunidades ícticas de arrecifes someros en las Bahía de Capurganá y en la Ensenada del Aguacate Caribe - Chocó

Ecólogo (a)Pregrad

Long-term evaluation of a forward osmosis-nanofiltration demonstration plant for wastewater reuse in agriculture

Hybrid forward osmosis (FO) processes such as forward osmosis with membrane bioreactors (FO-MBR), electrodialysis (FO-ED), nanofiltration (FO-NF) or reverse osmosis (FO-RO) present promising technologies for wastewater reuse in agriculture as they meet high effluent quality requirements, especially regarding boron and/or salt content. An FO-NF demonstration plant for this application was built and operated treating 3 m3 h−1 of real wastewater with a salinity of 3-5 mS cm−1 and 1.5 mg L−1 of boron in continuous mode for 480 days. Three draw solutions (DS) were evaluated in different periods of experimentation. Sodium polyacrylate led to reversible fouling on the FO and NF membranes and the permeate was not suitable for irrigation. Magnesium sulphate, used as DS in a second phase, generated severe irreversible fouling on NF membranes and therefore it was discarded. Finally, magnesium chloride showed the best performance, with FO-NF membranes presenting a stable permeability and low membrane fouling during long-term operation. The FO-NF permeate showed high quality for irrigation, achieving a conductivity value of 1 mS cm−1, a boron concentration below 0.4 mg L−1 and an average SAR of 1.98 (mequ L−1)0.5. DS replacement costs were reduced by working with high rejection NF membranes. However, energy consumption costs associated with the NF step make the global process more energy intensive than conventional technology.

Safe Cultivation of Medicago sativa in Metal-Polluted Soils from Semi-Arid Regions Assisted by Heatand Metallo-Resistant PGPR

Soil contamination with heavy metals is a constraint for plant establishment and development for which phytoremediation may be a solution, since rhizobacteria may alleviate plant stress under these conditions. A greenhouse experiment was conducted to elucidate the effect of toxic metals on growth, the activities of ROS (reactive oxygen species)-scavenging enzymes, and gene expression of Medicago sativa grown under different metal and/or inoculation treatments. The results showed that, besides reducing biomass, heavy metals negatively affected physiological parameters such as chlorophyll fluorescence and gas exchange, while increasing ROS-scavenging enzyme activities. Inoculation of M. sativa with a bacterial consortium of heat- and metallo-resistant bacteria alleviated metal stress, as deduced from the improvement of growth, lower levels of antioxidant enzymes, and increased physiological parameters. The bacteria were able to effectively colonize and form biofilms onto the roots of plants cultivated in the presence of metals, as observed by scanning electron microscopy. Results also evidenced the important role of glutathione reductase (GR), phytochelatin synthase (PCS), and metal transporter NRAMP1 genes as pathways for metal stress management, whereas the gene coding for cytochrome P450 (CP450) seemed to be regulated by the presence of the bacteria. These outcomes showed that the interaction of metal-resistant rhizobacteria/legumes can be used as an instrument to remediate metal-contaminated soils, while cultivation of inoculated legumes on these soils is still safe for animal grazing, since inoculation with bacteria diminished the concentrations of heavy metals accumulated in the aboveground parts of the plants to below toxic levelsMarruecos. Centre National pour la Recherche Scientifique et Technique (CNRST)-España, Ministerio de Economía y Competitividad (MINECO)-PPR2 /2016/42Unión Europea (FEDER)-CGL2016-75550-

Numerical study of sub-millimeter Gunn oscillations in InP and GaN vertical diodes: Dependence on bias, doping, and length

In this work, we report on Monte Carlo simulations of InP and GaN vertical Gunn diodes to optimize their oscillation frequency and DC to AC conversion efficiency. We show that equivalent operating conditions are achieved by the direct application of a sinusoidal AC voltage superimposed to the DC bias and by the simulation of the intrinsic device coupled with the consistent solution of a parallel RLC resonant circuit connected in series. InP diodes with active region about 1 μm offer a conversion efficiency up to 5.5 % for frequencies around 225 GHz. By virtue of the larger saturation velocity, for a given diode length, oscillation frequencies in GaN diodes are higher than for InP structures. Current oscillations at frequencies as high as 675 GHz, with 0.1 % efficiency, are predicted at the sixth generation band in a 0.9 μm long GaN diode, corroborating the suitability of GaN to operate near the THz band. At the first generation band, structures with notch in general provide lower oscillation frequencies and efficiencies in comparison with the same structures without notch.However, a higher number of generation bands are originated in notched diodes, thus typically reaching larger frequencies. Self-heating effects reduce the performance, but in GaN diodes the efficiency is not significantly degraded.ROOTHz project (FP7-243845

High diversity and suggested endemicity of culturable Actinobacteria in an extremely oligotrophic desert oasis

The phylum Actinobacteria constitutes one of the largest and anciently divergent phyla within the Bacteria domain. Actinobacterial diversity has been thoroughly researched in various environments due to its unique biotechnological potential. Such studies have focused mostly on soil communities, but more recently marine and extreme environments have also been explored, finding rare taxa and demonstrating dispersal limitation and biogeographic patterns for Streptomyces. To test the distribution of Actinobacteria populations on a small scale, we chose the extremely oligotrophic and biodiverse Cuatro Cienegas Basin (CCB), an endangered oasis in the Chihuahuan desert to assess the diversity and uniqueness of Actinobacteria in the Churince System with a culture-dependent approach over a period of three years, using nine selective media. The 16S rDNA of putative Actinobacteria were sequenced using both bacteria universal and phylum-specific primer pairs. Phylogenetic reconstructions were performed to analyze OTUs clustering and taxonomic identification of the isolates in an evolutionary context, using validated type species of Streptomyces from previously phylogenies as a reference. Rarefaction analysis for total Actinobacteria and for Streptomyces isolates were performed to estimate species' richness in the intermediate lagoon (IL) in the oligotrophic Churince system. A total of 350 morphologically and nutritionally diverse isolates were successfully cultured and characterized as members of the Phylum Actinobacteria. A total of 105 from the total isolates were successfully subcultured, processed for DNA extraction and 16S-rDNA sequenced. All strains belong to the order Actinomycetales, encompassing 11 genera of Actinobacteria; the genus Streptomyces was found to be the most abundant taxa in all the media tested throughout the 3- year sampling period. Phylogenetic analysis of our isolates and another 667 reference strains of the family Streptomycetaceae shows that our isolation effort produced 38 unique OTUs in six new monophyletic clades. This high biodiversity and uniqueness of Actinobacteria in an extreme oligotrophic environment, which has previously been reported for its diversity and endemicity, is a suggestive sign of microbial biogeography of Actinobacteria and it also represents an invaluable source of biological material for future ecological and bioprospecting studies

Multiscale understanding of tricalcium silicate hydration reactions

Tricalcium silicate, the main constituent of Portland cement, hydrates to produce crystalline calcium hydroxide and calcium-silicate-hydrates (C-S-H) nanocrystalline gel. This hydration reaction is poorly understood at the nanoscale. The understanding of atomic arrangement in nanocrystalline phases is intrinsically complicated and this challenge is exacerbated by the presence of additional crystalline phase(s). Here, we use calorimetry and synchrotron X-ray powder diffraction to quantitatively follow tricalcium silicate hydration process: i) its dissolution, ii) portlandite crystallization and iii) C-S-H gel precipitation. Chiefly, synchrotron pair distribution function (PDF) allows to identify a defective clinotobermorite, Ca11Si9O28(OH)2.8.5H2O, as the nanocrystalline component of C-S-H. Furthermore, PDF analysis also indicates that C-S-H gel contains monolayer calcium hydroxide which is stretched as recently predicted by first principles calculations. These outcomes, plus additional laboratory characterization, yielded a multiscale picture for C-S-H nanocomposite gel which explains the observed densities and Ca/Si atomic ratios at the nano- and meso- scales.This work has been supported by Spanish MINECO through BIA2014-57658-C2-2-R, which is co-funded by FEDER, BIA2014-57658-C2-1-R and I3 (IEDI-2016-0079) grants. We also thank CELLS-ALBA (Barcelona, Spain) for providing synchrotron beam time at BL04-MSPD beamline