2,304 research outputs found

    Dynamical generation of interwoven soliton trains by nonlinear emission in binary Bose-Einstein condensates

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    We propose a method for the generation of trains of alternating bright solitons in two-component Bose-Einstein condensates, using controlled emission of nonlinear matter-waves in the uncoupled regime with spatially-varying intra-species interaction and out-of-phase oscillations of the ground states in the trap. Under this scheme, solitons are sequentially launched from the different components, and interact with each other through phase-independent cross-coupling. We obtain an analytical estimation of the critical condition for soliton emission using a geometric guiding model, in analogy with integrated optical systems. In addition, we show how strong initial perturbations in the system can trigger the spontaneous generation of supersolitons, i.e. localized phonon-like excitations of the soliton trains. Finally, we demonstrate the controllable generation of slow and fast supersolitons by adding external localized potentials in the nonlinear region

    Nanoplastics: From tissue accumulation to cell translocation into Mytilus galloprovincialis hemocytes. resilience of immune cells exposed to nanoplastics and nanoplastics plus Vibrio splendidus combination

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    Plastic litter is an issue of global concern. In this work Mytilus galloprovincialis was used to study the distribution and effects of polystyrene nanoplastics (PS NPs) of different sizes (50 nm, 100 nm and 1 mu m) on immune cells. Internalization and translocation of NPs to hemolymph were carried out by in vivo experiments, while endocytic routes and effects of PS NPs on hemocytes were studied in vitro. The smallest PS NPs tested were detected in the digestive gland and muscle. A fast and size-dependent translocation of PS NPs to the hemolymph was recorded after 3 h of exposure. The internalization rate of 50 nm PS NPs was lower when caveolae and clathrin endocytosis pathways were inhibited. On the other hand, the internalization of larger particles decreased when phagocytosis was inhibited. The hemocytes exposed to NPs had changes in motility, apoptosis, ROS and phagocytic capacity. However, they showed resilience when were infected with bacteria after PS NP exposure being able to recover their phagocytic capacity although the expression of the antimicrobial peptide Myticin C was reduced. Our findings show for the first time the translocation of PS NPs into hemocytes and how their effects trigger the loss of its functional parameters

    Continuous atom laser with Bose-Einstein condensates involving three-body interactions

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    We demonstrate, through numerical simulations, the emission of a coherent continuous matter wave of constant amplitude from a Bose-Einstein Condensate in a shallow optical dipole trap. The process is achieved by spatial control of the variations of the scattering length along the trapping axis, including elastic three body interactions due to dipole interactions. In our approach, the outcoupling mechanism are atomic interactions and thus, the trap remains unaltered. We calculate analytically the parameters for the experimental implementation of this CW atom laser.Comment: 11 pages, 4 figure

    Estudio experimental de la extracción de carragenano a partir del alga Iridaea laminarioides

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    El objetivo de este trabajo fue hacer un estudio de factibilidad técnica de un proceso de extracción de carragenano a partir del alga roja Iridaea laminarioides, considerando que la recolección nacional de algas productoras de este polisacárido bordea las 3.000 Ton/año. Se estableció la influencia que tienen sobre el rendimiento y la calidad del producto obtenido, las variables siguientes: tiempo de extracción, relación volumen de solvente de extracción a masa de alga seca, volumen del agente precipitante, tiempo y velocidad de centrifugación, decoloración, etc. El proceso estudiado proporciona un producto blanco, de viscosidad promedio igual a 50 cp para soluciones al 1% en peso a 25°C y que forma geles fuertes cuando se lo trata con hidróxido de potasio. El rendimiento de producto es 70% y corresponde aproximadamente al 400 /o de la masa inicial de alga seca (19% humedad base seca)

    Myrosmodes nervosa (Orchidaceae, Cranichidinae, subgenus Myrosmodes): nueva combinación de Myrosmodes para Chile

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    De acuerdo a datos macromorfológicos y de hábitat se transfiere Altensteinia nervosa Kraenzl. al género Myrosmodes. Se describela especie y se establece el tipo.De acuerdo a datos macromorfológicos y de hábitat se transfiere Altensteinia nervosa Kraenzl. al género Myrosmodes. Se describela especie y se establece el tipo

    Conversion of HVAC Lines into HVDC in Transmission Expansion Planning

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    This paper presents a transmission planning methodology that considers the conversion of HVAC transmission lines to HVDC as an alternative of expansion of power systems, as a consequence of restrictions for the construction of new lines. The transmission expansion planning problem formulates an optimization problem that minimizes the total cost that includes the investment cost to convert lines from HVAC to HVDC and possible required reinforcements of the power system prior to the conversion. The costs analysis assesses the impact of the conversion on the reliability because transmission lines are out of service during the conversion work. The presented methodology is applied to a test system considering a planning a horizon of 10 years

    LEDGF/p75 TATA-less promoter is driven by the transcription factor Sp1.

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    PSIP1 (PC4 and SFRS1 interacting protein 1) encodes two splice variants: lens epithelium-derived growth factor or p75 (LEDGF/p75) and p52. PSIP1 gene products were shown to be involved in transcriptional regulation, affecting a plethora of cellular processes, including cell proliferation, cell survival, and stress response. Furthermore, LEDGF/p75 has implications for various diseases and infections, including autoimmunity, leukemia, embryo development, psoriasis, and human immunodeficiency virus integration. Here, we reported the first characterization of the PSIP1 promoter. Using 5' RNA ligase-mediated rapid amplification of cDNA ends, we identified novel transcription start sites in different cell types. Using a luciferase reporter system, we identified regulatory elements controlling the expression of LEDGF/p75 and p52. These include (i) minimal promoters (-112/+59 and +609/+781) that drive the basal expression of LEDGF/p75 and of the shorter splice variant p52, respectively; (ii) a sequence (+319/+397) that may control the ratio of LEDGF/p75 expression to p52 expression; and (iii) a strong enhancer (-320/-207) implicated in the modulation of LEDGF/p75 transcriptional activity. Computational, biochemical, and genetic approaches enabled us to identify the transcription factor Sp1 as a key modulator of the PSIP1 promoter, controlling LEDGF/p75 transcription through two binding sites at -72/-64 and -46/-36. Overall, our results provide initial data concerning LEDGF/p75 promoter regulation, giving new insights to further understand its biological function and opening the door for new therapeutic strategies in which LEDGF/p75 is involved

    The pitfall-trap of species conservation priority setting

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    This an accepted author's manuscript (AAM) version of an article published in Biodiversity and Conservation, 20 (2011): 663-68
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