Recursos de colección

Universidad Nacional de La Plata (88.541 recursos)

Este servicio se brinda en el marco del Proyecto de Enlace de Bibliotecas (PrEBi) y significa una novedosa iniciativa en pos de la difusión a través de Internet, dentro y fuera del ámbito de la Universidad, de los conocimientos que en ella se generan para servir como vehículo de promoción y jerarquización. Los objetivos que se han planteados para SeDiCI son sumamente ambiciosos e incluyen la difusion electrónica de tesis, tesinas y disertaciones pero también de otros tipos de creaciones intelectuales, pretendiendo abarcar la ciencia, la tecnología y el arte buscando modos de presentación no solo de objetos en forma de documentos de texto sino también otros medios multimediales aptos para creaciones no documentales.

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Mostrando recursos 1 - 20 de 28

  1. Spectroscopic and Microscopic Characterization of Volcanic Ash from Puyehue-(Chile) Eruption: Preliminary Approach for the Application in the Arsenic Removal

    Botto, Irma Lía; Canafoglia, María Elena; Gazzoli, Delia; González, María José
    Volcanic ash from Puyehue Cordon Caulle Volcanic Complex (Chile), emitted on June 4, 2011, and deposited inVilla LaAngostura at ∼40 kmof the source, was collected and analyzed by Raman spectroscopy, optical and scanning electron microscopy (SEM-EDS), Xray diffraction (XRD), surface area (BET), and chemical analysis (ICP-AES-MS technique).Themineralogical and physicochemical study revealed that the pyroclastic mixture contains iron oxides in the form of magnetite and hematite as well as pyroxene and plagioclase mineral species and amorphous pumiceous shards. Carbonaceous material was also identified. Physicochemical techniques allow us to select two representative samples (average composition and Fe-rich materials) which were used to...

  2. Structural Characterization of Natural and Processed Zircons with X-Rays and Nuclear Techniques

    Damonte, Laura Cristina; Rivas, Patricia; Pasquevich, Alberto F.; Andreola, Fernanda; Bondioli, Federica; Ferrari, Anna M.; Tositti, Laura; Cinelli, Giorgia
    In ceramic industry, zircon sand is widely used in different applications because zirconia plays a role as common opacifying constituent. In particular, it is used as a basic component of glazes applied to ceramic tiles and sanitary ware as well as an opacifier in unglazed bulk porcelain stoneware. Natural zircon sands are the major source of zirconium minerals for industrial applications. In this paper, long, medium, and short range studies were conducted on zirconium minerals originated from Australia, South Africa, and United States of America using conventional and less conventional techniques (i.e., X-Ray Diffraction (XRD), Positron Annihilation Lifetime Spectroscopy (PALS),...

  3. Relative Entropies and Jensen Divergences in the Classical Limit

    Kowalski, Andrés; Plastino, Ángel Luis
    Metrics and distances in probability spaces have shown to be useful tools for physical purposes. Here we use this idea, with emphasis on Jensen Divergences and relative entropies, to investigate features of the road towards the classical limit. A well-known semiclassical model is used and recourse is made to numerical techniques, via the well-known Bandt and Pompe methodology, to extract probability distributions from the pertinent time-series associated with dynamical data.

  4. Immunization with the Recombinant Cholera Toxin B Fused to Fimbria 2 Protein Protects against Bordetella pertussis Infection

    Olivera, Noelia; Castuma, Celina E.; Hozbor, Daniela Flavia; Gaillard, María Emilia; Rumbo, Martín; Gómez, Ricardo Martín
    This study examined the immunogenic properties of the fusion protein fimbria 2 of Bordetella pertussis (Fim2)—cholera toxin B subunit (CTB) in the intranasal murine model of infection. To this end B. pertussis Fim2 coding sequence was cloned downstream of the cholera toxin B subunit coding sequence.Theexpression and assembly of the fusion protein into pentameric structures (CTBFim2) were evaluated by SDS-PAGE and monosialotetrahexosylgaglioside (GM1-ganglioside) enzyme-linked immunosorbent assay (ELISA). To evaluate the protective capacity of CTB-Fim2, an intraperitoneal or intranasal mouse immunization schedule was performed with 50 μg of CTB-Fim2. Recombinant (rFim2) or purified (BpFim2) Fim2, CTB, and phosphate-buffered saline (PBS) were...

  5. Essential Oils of Plants as Biocides against Microorganisms Isolated from Cuban and Argentine Documentary Heritage

    Borrego, Sofía; Valdés, Oderlaise; Vivar, Isbel; Lavin, Paola; Guiamet, Patricia; Battistoni, Patricia A.; Gómez de Saravia, Sandra Gabriela; Borges, Pedro
    Natural products obtained from plants with biocidal activity represent an alternative and useful source in the control of biodeterioration of documentary heritage, without negative environmental and human impacts. In this work, we studied the antimicrobial activity of seven essential oils against microorganisms associated with the biodeterioration of documentary heritage. The essential oils were obtained by steam distillation. The antimicrobial activity was analyzed using the agar diffusion method against 4 strains of fungi and 6 bacterial strains isolated fromrepositories air and documents of theNational Archive of the Republic of Cuba and theHistorical Archive of theMuseum of La Plata, Argentina. Anise and...

  6. Determination of Indoor Air Quality in Archives and Biodeterioration of the Documentary Heritage

    Borrego, Sofía; Lavin, Paola; Perdomo, Ivette; Gómez de Saravia, Sandra Gabriela; Guiamet, Patricia
    Documentary heritage is permanently subject to suffering from physical, chemical, and/or biological alterations. Biological deterioration by microorganisms (bacteria and fungi) causes undesirable changes on material properties. Microorganisms affect different organic, natural or synthetic substrates (cellulose, polycarbonates), metals, and compounds of optical and magnetic devices (CD, VHS). Paper made by vegetal fibers, functional additives (glue, optical polishers, consolidating agents), and inks with organic bindings are used as sources of nutrients. The environmental microorganisms that formthe microbial charge of indoor air at repositories (archives, libraries) storing cultural heritage can deteriorate the different supports of heritage importance and affect human health as allergies...

  7. Total Oxidation of Naphthalene with Zirconia-Supported Cobalt, Copper and Nickel Catalysts

    Leguizamón Aparicio, María Silvia del Valle; Ocsachoque, Marco Antonio; Gazzoli, Delia; Botto, Irma Lía; Lick, Ileana Daniela
    ZrO2 nH2O (hydrogel) impregnated with transition metals (Cu, Co, and Ni) was studied in this work as a precursor for the synthesis of CuO/ZrO2 (CuZ), CoOx/ZrO2 (CoZ), and NiO/ZrO2 (NiZ) catalysts, employed in the naphthalene oxidation reaction. Fresh and catalytically used materials were characterized by different physicochemical techniques, to compare the bulk and surface behavior, with particular attention to the effect of the supported metal species’ properties on the catalytic activity. Techniques such as X-ray diffraction (XRD), temperature programmed reduction (TPR), differential scanning calorimetry (DSC), Brunauer–Emmett–Teller (BET) surface area analyzer, diffuse reflectance spectroscopy (DRS UV–vis), and Raman spectroscopy, allow for...

  8. Hydrothermal Stability of Ru/SiO2–C: A Promising Catalyst for Biomass Processing through Liquid-Phase Reactions

    Gatti, Martín N.; Lombardi, María Bárbara; Gazzoli, Delia; Santori, Gerardo Fabián; Pompeo, Francisco; Nichio, Nora N.
    In this work, structural and morphological properties of SiO2–C composite material to be used as support for catalysts in the conversion of biomass-derived oxygenated hydrocarbons, such as glycerol, were investigated in liquid water under various temperatures conditions. The results show that this material does not lose surface area, and the hot liquid water does not generate changes in the structure. Neither change in relative concentrations of oxygen functional groups nor in Si/C ratio due to hydrothermal treatment was revealed by X-ray photoelectron spectroscopy (XPS) analysis. Raman analysis showed that the material is made of a disordered graphitic structure in an...

  9. Genetic Differentiation of North-East Argentina Populations Based on 30 Binary X Chromosome Markers

    Di Santo Meztler, Gabriela Paula; Palacio, Santiago del; Esteban, María E.; Armoa, Isaías; Argüelles, Carina Francisca; Catanesi, Cecilia Inés
    Alu insertions, INDELs, and SNPs in the X chromosome can be useful not only for revealing relationships among populations but also for identification purposes. We present data of 10 Alu insertions, 5 INDELs, and 15 SNPs of X-chromosome from three Argentinian north-east cities in order to gain insight into the genetic diversity of the X chromosome within this region of the country. Data from 198 unrelated individuals belonging to Posadas, Corrientes, and Eldorado cities were genotyped for Ya5DP62, Yb8DP49, Ya5DP3, Ya5NBC37, Ya5DP77, Ya5NBC491, Ya5DP4, Ya5DP13, Yb8NBC634, and Yb8NBC102 Alu insertions, for MID193, MID1705, MID3754, MID3756 and MID1540 Indels and for...

  10. Advanced glycation end-products (AGEs) induce concerted changes in the osteoblastic expression of their receptor RAGE and in the activation of extracellular signal-regulated kinases (ERK)

    Cortizo, Ana María; Lettieri, María Gabriela; Barrio, Daniel Alejandro; Mercer, Natalia; Etcheverry, Susana B.; McCarthy, Antonio Desmond
    An increase in the interaction between advanced glycation end-products (AGEs) and their receptor RAGE is believed to contribute to the pathogenesis of chronic complications of Diabetes mellitus, which can include bone alterations such as osteopenia. We have recently found that extracellular AGEs can directly regulate the growth and development of rat osteosarcoma UMR106 cells, and of mouse calvaria-derived MC3T3E1 osteoblasts throughout their successive developmental stages (proliferation, differentiation and mineralisation), possibly by the recognition of AGEs moieties by specific osteoblastic receptors which are present in both cell lines. In the present study we examined the possible expression of RAGE by UMR106...

  11. The Dyon Charge in Noncommutative Gauge Theories

    Cieri, L.; Shaposnik, Fidel
    We construct a dyon solution for the noncommutative version of the Yang-Mills-Higgs model with a ϑ-term. Extending the Noether method to the case of a noncommutative gauge theory, we analyze the effect of CP violation induced both by the ϑ- term and by noncommutativity proving that theWitten effect formula for the dyon charge remains the same as in ordinary space.

  12. Genetic differentiation of North-east Argentina populations based on 30 binary X chromosome markers

    Di Santo Meztler, Gabriela Paula; Palacio, G. P. del; Esteban, M. E.; Armoa, Isaías; Argüelles, C. F.; Catanesi, Cecilia Inés
    Material suplementario que contiene la genotipificación de los individuos usados en el artículo citado.

  13. Relación entre el gen Rps 1k y la resistencia a Pythium ultimum y P. irregulare en soja

    Grijalba, Pablo Esteban; Ridao, Azucena del Carmen; Steciow, Mónica Mirta; López, María Virginia
    En el cultivo de soja Pythium spp. produce la pudrición de semillas y raíces, y “damping off”. El objetivo del presente trabajo fue verificar la relación entre el gen Rps 1k de resistencia a Phytophthora sojae y P. ultimum y P. irregulare. Cuatro genotipos de soja, dos con el gen Rps 1k (SE+1y SE+2) y dos sin el gen (SE-1 y SE-2) se sembraron en suelo inoculado y sin inocular. Los genotipos SE-1 y SE-2 no difirieron entre sí, ya sea que estuviesen inoculados o no, ni tampoco difirieron del SE+2. En cambio, los genotipos con el gen Rps1k difirieron...

  14. Interrogantes en la tecnología de la inoculación de semillas de soja con Bradyrhizobium spp.

    Lodeiro, Aníbal Roberto
    Con el fin de aprovechar la fijación simbiótica de nitrógeno, el cultivo de soja se inocula con cepas seleccionadas de Bradyrhizobium japonicum, Bradyrhizobium diazoefficiens o Bradyrhizobium elkanii (conjuntamente referidas como Bradyrhizobium spp.). El método más común de hacerlo es la inoculación en semillas, ya sea que esta se realice en el momento previo a la siembra o que se utilicen semillas preinoculadas o pretratadas mediante el tratamiento profesional de semillas. La metodología de inoculación no debe limitarse a recubrir las semillas con rizobios vivos, sino que también debe optimizar las chances de esos rizobios para infectar las raíces y nodular....

  15. Applications of Infrared and Raman Spectroscopies to Probiotic Investigation

    Santos, Mauricio; Gerbino, Oscar Esteban; Tymczyszyn, Elizabeth; Gómez Zavaglia, Andrea
    In this review, we overview the most important contributions of vibrational spectroscopy based techniques in the study of probiotics and lactic acid bacteria. First, we briefly introduce the fundamentals of these techniques, together with the main multivariate analytical tools used for spectral interpretation. Then, four main groups of applications are reported: (a) bacterial taxonomy (Subsection 4.1); (b) bacterial preservation (Subsection 4.2); (c) monitoring processes involving lactic acid bacteria and probiotics (Subsection 4.3); (d) imaging-based applications (Subsection 4.4). A final conclusion, underlying the potentialities of these techniques, is presented.

  16. Satureja montana: evaluación como agente antifúngico en pinturas para prevención del biodeterioro

    Bogdan, Sofía; Romagnoli, Roberto; Deyá, Marta Cecilia
    El biodeterioro constituye un conjunto de procesos físicos y químicos que generan alteraciones en diversos materiales. La prevención del crecimiento de mohos, así como el desarrollo de medidas de tratamiento apropiadas para los objetos contaminados, son un desafío permanente. En este sentido, las pinturas y recubrimientos en general juegan un papel importante como sistemas de conservación y protección de los distintos objetos. El objetivo de este trabajo de investigación fue, en una primera instancia, evaluar la actividad antifúngica in vitro del aceite esencial de Satureja montana (Sm) para luego incorporarlo en una formulación de pintura látex como agente biocida y...

  17. Organización y conservación de la colección de hongos patógenos y simbiontes de insectos y otros artrópodos del CEPAVE (CONICET-UNLP), La Plata, Argentina

    Gutiérrez, Alejandra Concepción; Tornesello Galván, Julieta; Manfrino, Romina Guadalupe; Hipperdinger, Marcela; Falvo, Marianel; D'Alessandro, Celeste; López Lastra, Claudia Cristina
    La colección de hongos patógenos y simbiontes de insectos y otros artrópodos del Centro de Estudios Parasitológicos y de Vectores es única por sus características específicas en la Argentina y por preservar hongos en cultivo, in vitro e in vivo. Esta colección está abierta para actividades de investigación, docencia, servicios y asesoramiento público y privado. Un total de 421 aislamientos pertenecientes a 23 géneros (Ascomycota: 16, Entomophthoromycotina: 4 Glomeromycota: 2 y Oomycota: 1) son preservados en la colección mediante diversos métodos: criopreservación en freezer a −20 ◦ C y −70 ◦C, agua destilada estéril, papel, arena y liofilización. Las cepas...

  18. Fases cuánticas y degeneración clásica en un antiferromagneto cuántico sobre la red de panal de abejas de dos capas

    Lamas, Carlos Alberto; Arlego, Marcelo José Fabián
    En este trabajo estudiamos la evolución de una fase de dímeros cuánticos sobre la red de tipo panal de abejas utilizando una representación de los operadores de espín en términos de operadores bosónicos. Este modelo ha sido propuesto para describir las propiedades del material Bi3Mn4O12(NO3), por lo que el presente estudio puede ser relevante para describir el magnetismo de este material y otros con características similares. Llevando a cabo un desacoplamiento de campo medio, calculamos la relación de dispersión y a partir de la misma determinamos el gap de espín. Interesantemente, aunque el cierre de gap es calculado en un...

  19. Quantum phase diagram of a frustrated antiferromagnet on the bilayer honeycomb lattice

    Zhang, Hao; Lamas, Carlos Alberto; Arlego, Marcelo José Fabián; Brenig, Wolfram
    We study the spin-1/2 Heisenberg antiferromagnet on a bilayer honeycomb lattice including interlayer frustration. Using a set of complementary approaches, namely, Schwinger bosons, dimer series expansion, bond operators, and exact diagonalization, we map out the quantum phase diagram. Analyzing ground-state energies and elementary excitation spectra, we find four distinct phases, corresponding to three collinear magnetic long-range ordered states, and one quantum disordered interlayer dimer phase. We detail that the latter phase is adiabatically connected to an exact singlet product ground state of the bilayer, which exists along a line of maximum interlayer frustration. The order within the remaining three phases...

  20. Medición de la deformación de una barra metálica por medio de la holografía interferométrica

    Calatroni, J.A.S.; Lunazzi, Jose Joaquín; Rabal, Héctor Jorge; Garavaglia, Mario J.
    Una barra metálica sostenida por uno de sus extremos es sometida primeramente a la acción de su propio peso, y luego a la de una sobrecarga; en ambos casos se realiza una toma holográfica de modo que ambas tomas se superponen sobre una misma placa. La reconstrucción de este holograma de doble exposición crea figuras de interferencia que corresponden a la diferencia entre ambas posiciones de la barra. Sé logra de este modo medir con precisión interferométrica la deformación de una barra metálica cualquiera,aunque esta no haya sido preparada ópticamente como lo sería en el caso de una medición interferométrica común. Este...

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