1,171 research outputs found

    Behavior of a Model Dynamical System with Applications to Weak Turbulence

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    We experimentally explore solutions to a model Hamiltonian dynamical system derived in Colliander et al., 2012, to study frequency cascades in the cubic defocusing nonlinear Schr\"odinger equation on the torus. Our results include a statistical analysis of the evolution of data with localized amplitudes and random phases, which supports the conjecture that energy cascades are a generic phenomenon. We also identify stationary solutions, periodic solutions in an associated problem and find experimental evidence of hyperbolic behavior. Many of our results rely upon reframing the dynamical system using a hydrodynamic formulation.Comment: 22 pages, 14 figure

    Inhalation of growth factors and apo-transferrin to protect and repair the hypoxic-ischemic brain

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    Hypoxic-ischemic brain damage is a major contributor to chronic neurological dysfunction and acute mortality in infants as well as in adults. In this review, we summarize recent publications demonstrating that the intranasal administration (INA) of apo-transferrin (aTf) and different growth factors provides neuroprotection to the mouse and rat brain after a hypoxic-ischemic event. The intranasal delivery of growth factors such as insulin-like growth factor-1 (IGF-1) and vascular endothelial growth factor (VEGF) has been found to improve neurological function and reduce infarct size in adult rats after a hypoxic-ischemic event. On the other hand, INA of aTf and epidermal growth factor (EGF) were effective in reducing white matter damage and inflammation and in promoting the proliferation and survival of oligodendroglial progenitor cells (OPCs) in a model of hypoxic-ischemic encephalopathy. Therefore, data summarized in this review suggest that INA of growth factors and aTf can be used in combination in clinical treatment in order to protect and repair the hypoxic-ischemic brain.Fil: Guardia Clausi, Mariano. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de QuĂ­mica y FĂ­sico-QuĂ­mica BiolĂłgicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y BioquĂ­mica. Instituto de QuĂ­mica y FĂ­sico-QuĂ­mica BiolĂłgicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂ­mica. Departamento de QuĂ­mica BiolĂłgica; Argentina. Rutgers-New Jersey Medical School; Estados UnidosFil: Paez, P. M.. State University of New York; Estados UnidosFil: Pasquini, Laura Andrea. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂ­mica. Departamento de QuĂ­mica BiolĂłgica; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de QuĂ­mica y FĂ­sico-QuĂ­mica BiolĂłgicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y BioquĂ­mica. Instituto de QuĂ­mica y FĂ­sico-QuĂ­mica BiolĂłgicas; ArgentinaFil: Pasquini, Juana Maria. Universidad de Buenos Aires. Facultad de Farmacia y BioquĂ­mica. Departamento de QuĂ­mica BiolĂłgica; Argentina. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Houssay. Instituto de QuĂ­mica y FĂ­sico-QuĂ­mica BiolĂłgicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y BioquĂ­mica. Instituto de QuĂ­mica y FĂ­sico-QuĂ­mica BiolĂłgicas; Argentin

    Production management model through MPS and line balancing to reduce the non-fulfillment of orders in lingerie clothing MSEs in Peru

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    The focus of this research is to establish control and planning management in the sewing production process of lingerie clothing to better prepare companies for demand growth. The lack of improvement tools in this sector, the lack of staff training and a lack of quality culture has led to companies, especially MYPES, not being able to meet the established delivery times and non-fulfillment of orders with the customers, which represents 80% of dissatisfied orders due to the limited production capacity and non-productive time in the plant. This problem is due to limited production capacity, deficient production planning, and lack of materials. In order to solve this problem, industrial engineering tools were used. The application of these tools improved production from 79% to 95%

    Surfactant effects in monodisperse magnetite nanoparticles of controlled size

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    Monodisperse magnetite Fe3O4 nanoparticles of controlled size within 6 and 20 nm in diameter were synthesized by thermal decomposition of an iron organic precursor in an organic medium. Particles were coated with oleic acid. For all samples studied, saturation magnetization Ms reaches the expected value for bulk magnetite, in contrast to results in small particle systems for which Ms is usually much smaller due to surface spin disorder. The coercive field for the 6 nm particles is also similar to that of bulk magnetite. Both results suggest that the oleic acid molecules covalently bonded to the nanoparticle surface yield a strong reduction in the surface spin disorder. However, although the saturated state may be similar, the approach to saturation is different and, in particular, the high-field differential susceptibility is one order of magnitude larger than in bulk materials. The relevance of these results in biomedical applications is discussed.Comment: 3 pages, 3 figures. Presented at JEMS 2006 (San Sebastian, Spain). Submitted to JMM

    Plasma membrane redox system in the erythrocytes of rowers: Pilot study

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    The oxidative stress results from a change in the physiological balance between oxidant and antioxidant species. This type of stress is a chemical change in the redox state of cells. The increased production of reactive species is related to an excessive metabolic activation, for example, from an intense physical exercise or an excessive caloric intake (1). In physiological conditions, muscle fibers are provided with an antioxidant system able to keep under control the excessive production of Reactive Oxygen Species (ROS)

    Evaluation of a Multicommuted Flow System for Photometric Environmental Measurements

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    A portable flow analysis instrument is described for in situ photometric measurements. This system is based on light-emitting diodes (LEDs) and a photodiode detector, coupled to a multipumping flow system. The whole equipment presents dimensions of 25  cm × 22  cm × 10  cm, weighs circa 3 kg, and costs 650 €. System performance was evaluated for different chemistries without changing hardware configuration for determinations of (i) Fe3+ with SCN-, (ii) iodometric nitrite determination, (iii) phenol with sodium nitroprusside, and (iv) 1-naphthol-N-methylcarbamate (carbaryl) with p-aminophenol. The detection limits were estimated as 22, 60, 25, and 60 ng mL -1 for iron, nitrite, phenol, and carbaryl at the 99.7% confidence level with RSD of 2.3, 1.0, 1.8, and 0.8%, respectively. Reagent and waste volumes were lower than those obtained by flow systems with continuous reagent addition. Sampling rates of 100, 110, 65, and 72 determinations per hour were achieved for iron, nitrite, phenol, and carbaryl determination

    The draft genome of Andean Rhodopseudomonas sp. strain AZUL predicts genome plasticity and adaptation to chemical homeostasis

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    The genus Rhodopseudomonas comprises purple non-sulfur bacteria with extremely versatile metabolisms. Characterization of several strains revealed that each is a distinct ecotype highly adapted to its specific micro-habitat. Here we present the sequencing, genomic comparison and functional annotation of AZUL, a Rhodopseudomonas strain isolated from a high altitude Andean lagoon dominated by extreme conditions and fluctuating levels of chemicals. Average nucleotide identity (ANI) analysis of 39 strains of this genus showed that the genome of AZUL is 96.2% identical to that of strain AAP120, which suggests that they belong to the same species. ANI values also show clear separation at the species level with the rest of the strains, being more closely related to R. palustris. Pangenomic analyses revealed that the genus Rhodopseudomonas has an open pangenome and that its core genome represents roughly 5 to 12% of the total gene repertoire of the genus. Functional annotation showed that AZUL has genes that participate in conferring genome plasticity and that, in addition to sharing the basal metabolic complexity of the genus, it is also specialized in metal and multidrug resistance and in responding to nutrient limitation. Our results also indicate that AZUL might have evolved to use some of the mechanisms involved in resistance as redox reactions for bioenergetic purposes. Most of those features are shared with strain AAP120, and mainly involve the presence of additional orthologs responsible for the mentioned processes. Altogether, our results suggest that AZUL, one of the few bacteria from its habitat with a sequenced genome, is highly adapted to the extreme and changing conditions that constitute its niche.Fil: Guardia, Aisha E. Ingeniería de Interfases y Bioprocesos. Instituto de Tecnología de Materiales (INTEMA-CONICET-UNMdP); Argentina.Fil: Busalmen, Juan P. Ingeniería de Interfases y Bioprocesos. Instituto de Tecnología de Materiales (INTEMA-CONICET-UNMdP); Argentina.Fil: Wagner, Agustín. Universidad Nacional de Rosario. Facultad de Ciencias Agrarias; Argentina.Fil: Di Capua, Cecilia Beatriz. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET-UNR); Argentina.Fil: Cortez, Néstor. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET-UNR); Argentina.Fil: Beligni, María V. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biológicas (IIB-CONICET-UNMdP); Argentina

    Diversidad de polen de Pinus aerovagante y patrón anual de su polinización en España

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    The authors wish to thank to different projects and entities for financing this study: COST ES0603 EUPOL; Laboratorios LETI S.A.; Proyecto EOLO-PAT; European Commission for «ENV4-CT98-0755»; Spanish Ministry of Science and Technology I+D+I for «AMB97-0457-CO7-021», «REN2001-10659-CO3-01», «BOS2002-03474», «CGL2004-21166-E», «CGL2005-07543/CLI», «CGL2009-11205» and CONSOLIDER CSD2007_00067 GRACCIE; Andalusian Government for «RNM-5058»; and Catalan Government AGAUR for «2002SGR00059», «2005SGR00519» and «2009SGR1102»
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