Search Results - "Mejia,María"

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Publication Catalog - "Mejia,María"

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  1. 1

    Study of the structural, thermal, rheological and film properties of functional copolymers of hydroxyethyl acrylate and methyl methacrylate

    Publication
    by Mejia,María
    Other Authors: Murillo,Edwin
    Origin: Oasisbr
    Abstract New functional polymers will be prepared using alkyd resins having high solid content (environmentally friendly) and comb-type structural morphology. Different copolymers of hydroxyethyl acrylate and methyl methacrylate (HEMMA) were synthesized by solution polymerization using azo-bis-(isobutyronitrile) (AIBN) as initiator and dimethylformamide as a solvent. The proportions utilized of AIBN were 0.5 (HEMMA1), 1.0 (HEMMA2), 1.5 (HEMMA3) and 2.0 wt. % (HEMMA4). The conversion percentage of the reaction was higher than 90%. The formation of the copolymers was evidenced by infrared analysis, hydroxyl value, and nuclear magnetic resonance. The intensity of OH group adsorption increased with the molecular weight and hydroxyl value. The polydispersity index was lower than 1.5. All copolymers exhibited a stable region on viscosity at a shear rate between 0.1 and 10 s–1. The copolymers exhibited good thermal stability, flexibility, and adherence.
    2016 article Brazil open access
  2. 2

    EFFECT OF PLANT EXTRACTS AND GROWTH SUBSTRATES ON CONTROLLING DAMPING-OFF IN PINUS TECUNUMANII SEEDLINGS

    Publication
    by Fajardo-Mejía,Maria Alejandra
    Other Authors: Morales-Osorio,Juan Gonzalo; Antonio,Guillermo; León-Peláez,Juan Diego
    Origin: Oasisbr
    ABSTRACT Damping-off is considered one of the most limiting phytosanitary problems in conifer seedling production because it may cause massive damage or total plant death in short time periods. This pathology is caused by a complex of microorganisms, the most common of which are Fusarium spp. and Rhizoctonia spp. This study evaluated the effect of growth substrates and plant extracts at different concentrations on germination and incidence of disease in Pinus tecunumanii plants. The plants were inoculated with the damping-off pathogen Fusarium oxysporum and treatments were applied in a completely randomized design with a factorial arrangement of 4x2x3. This corresponded to four substrates (pine bark, rice hull, coconut husk and sandy soil (4:1)); two plant extracts (Matricaria chamomilla and Datura stramonium), and three concentrations of each extract (Control concentration: 0%, Concentration 1: 50 % and Concentration 2: Undiluted). Each treatment had three repetitions, with 25 plants per repetition. The growth substrates affected germination; the most effective of these were sandy soil (4:1) and pine bark, with 90% and 92% germination at day 20, respectively. No significant difference was observed between the germination obtained with these substrates and that obtained with coconut husk after day 19. Meanwhile, all of the extracts had a significant effect on controlling the disease when they were combined with the substrates, with the exception of coconut husk. With this last substrate the incidence of disease was lower than 4% without the application of plant extracts; this indicates that coconut husk discourages the development of the disease on its own.
    2016 article Brazil open access
  3. 3

    A formação teórico-crítica do docente: a pesquisa-ação, uma experiência no México

    Publication
    by Mejía,María Noemí Alfaro
    Other Authors: Rodea,Marisela Colín; Castro,Helena Maria da Silva Gomes; González,Leonardo Herrera
    Origin: Oasisbr
    O propósito deste trabalho é abordar aspectos relacionados com a formação teórica e crítica do professor de línguas, vinculados com o exercício da reflexão do docente sobre seu desenvolvimento na aula, a procura de informação e o trabalho colaborativo entre pesquisadores e professores. Para conseguir o nosso objetivo, delineamos, em primeiro lugar, o perfil do professor de línguas estrangeiras (PLE), a partir de representações existentes entre docentes de línguas estrangeiras de um curso de formação docente no Centro de Ensino de Línguas Estrangeiras na Universidad Nacional Autónoma de México (CELE-UNAM). Para efeitos práticos, faremos referência, principalmente, ao docente da educação superior, mesmo que grande parte do aqui exposto atinge outros setores educativos. Em segundo lugar, abordamos a forma em que a noção de formação de professores foi construída no México, partindo das condições sociais em que arrancaram determinados programas de planejamento educacional, os quais procuravam favorecer a atualização acadêmica no país. Já na parte final do artigo, contextualizamos a nossa experiência como participantes no projeto Interação na sala de aula de Português como Língua Estrangeira, Pesquisa-Ação (PIA-PLE), levado a cabo na mesma universidade.
    2007 article Brazil open access
  4. 4

    Effect of plant extracts and growth substrates on controlling damping-off in Pinus tecunumanii seedlings

    Publication
    by Fajardo-Mejía, Maria Alejandra
    Other Authors: Morales-Osorio, Juan Gonzalo; Correa-Londoño, Guillermo Antonio; León-Peláez, Juan Diego
    Origin: Oasisbr
    Damping-off is considered one of the most limiting phytosanitary problems in conifer seedling production because it may cause massive damage or total plant death in short time periods. This pathology is caused by a complex of microorganisms, the most common of which are Fusarium spp. and Rhizoctonia spp. This study evaluated the effect of growth substrates and plant extracts at different concentrations on germination and incidence of disease in Pinus tecunumanii plants. The plants were inoculated with the damping-off pathogen Fusarium oxysporum and treatments were applied in a completely randomized design with a factorial arrangement of 4x2x3. This corresponded to four substrates (pine bark, rice hull, coconut husk and sandy soil (4:1)); two plant extracts (Matricaria chamomilla and Datura stramonium), and three concentrations of each extract (Control concentration: 0%, Concentration 1: 50 % and Concentration 2: Undiluted). Each treatment had three repetitions, with 25 plants per repetition. The growth substrates affected germination; the most effective of these were sandy soil (4:1) and pine bark, with 90% and 92% germination at day 20, respectively. No significant difference was observed between the germination obtained with these substrates and that obtained with coconut husk after day 19. Meanwhile, all of the extracts had a significant effect on controlling the disease when they were combined with the substrates, with the exception of coconut husk. With this last substrate the incidence of disease was lower than 4% without the application of plant extracts; this indicates that coconut husk discourages the development of the disease on its own.
  5. 5

    Estudio del ambiente empresarial transfronterizo entre las regiones del Alentejo (Portugal) y la Provincia de Huelva (España)

    Publication
    by Plaza Mejía, María de los Ángeles
    Other Authors: Vargas Sánchez, Alfonso; Sousa, António; Novas, Jorge
    En este estudio se ha analizado la evolución del comercio exterior y se han determinado los sectores en los que se mantienen relaciones comerciales transfronterizas regulares entre la provincia de Huelva y la región del Alentejo, así como las empresas que las llevan a cabo, siendo estas actividades económicas, por tanto, las que ofrecen más posibilidades de una cooperación empresarial efectiva. En este sentido, se identifican toda una serie de elementos ligados a la cooperación, siendo analizados desde la doble perspectiva onubense y alentejana: percepción de las oportunidades de negocio, impulsores de y barreras a la cooperación, nivel de confianza en los socios, cultura de internacionalización de las empresas, finalidad de la actividad transfronteriza (vendedora/exportadora, compradora/importadora o/y fabricación), recursos humanos y valoración de la experiencia transfronteriza. La metodología utilizada ha sido la de la realización de una encuesta personal, visitando todas y cada una de las empresas integrantes de la población objetivo.
    2012 book Portugal open access
  6. 6

    AMBIENTE EMPRESARIAL TRANSFRONTERIZO ENTRE LA PROVINCIA DE HUELVA Y LA REGIÓN DEL ALENTEJO

    Publication
    by Plaza-Mejía, María de los Ángeles
    Other Authors: Vargas-Sánchez, Alfonso; Casas Novas, Jorge; Sousa, António
    En este estudio se ha analizado la evolución del comercio exterior y se han determinado los sectores en los que se mantienen relaciones comerciales transfronterizas regulares entre la provincia de Huelva y la región del Alentejo, así como las empresas que las llevan a cabo, siendo estas actividades económicas, por tanto, las que ofrecen más posibilidades de una cooperación empresarial efectiva. En este sentido, se identifican toda una serie de elementos ligados a la cooperación, siendo analizados desde la doble perspectiva onubense y alentejana: percepción de las oportunidades de negocio, impulsores de y barreras a la cooperación, nivel de confianza en los socios, cultura de internacionalización de las empresas, finalidad de la actividad transfronteriza (vendedora/exportadora, compradora/importadora o/y fabricación), recursos humanos y valoración de la experiencia transfronteriza. La metodología utilizada ha sido la de la realización de una encuesta personal, visitando todas y cada una de las empresas integrantes de la población objetivo.
    2012 lecture Portugal open access
  7. 7

    Histological and microbiological aspects of actinomycetoma cases in Venezuela

    Publication
    by Serrano, José Antonio
    Other Authors: Beaman, Blaine; Mejia, Maria Antonieta; Viloria, Jesus Eduardo; Zamora, Ramón
    Origin: Oasisbr
    Os autores, em um período de 10 anos (1976/1986) realizaram urn estudo clínico, histopatológico e micológico em 47 casos de actinomicetoma. Os agentes etiológicos isolados foram: Actinomadura madurae - 20 cases (42,5%); Nocardia brasiliensis - 13 casos (27,6%); Nocardia spp - 7 casos (14,8%), Streptomyces somaliensis - 4 casos (8,5%); Nocardia asteroides - 2 casos (4,2%) e N. otitidis caviarum (N. caviae) - 1 caso (2,1%). A maioria dos casos procedia de zona rural, prevalecendo a infecção no sexo masculino (4:1). A idade dos pacientes variou de 18 a 80 anos. Dos 47 casos registrados, 24 foram observados no Estado de Lara. representando 51% do total das observações.
  8. 8

    La política farmacéutica nacional en Colombia y la reforma de la seguridad social: acceso y uso racional de medicamentos

    Publication
    by Mejía Restrepo,Samuel
    Other Authors: Vélez Arango,Alba Lucía; Buriticá Arboleda,Olga Clemencia; Arango Mejía,María Cristina; Río Gómez,Jaime Alberto del
    Origin: Oasisbr
    A partir del nuevo sistema de seguridad social en Colombia (1993) que consagra la equidad y la obligatoriedad como fundamentos del servicio público, se analiza si la formulación y la implementación de la política farmacéutica favorecen la accesibilidad, la disponibilidad y el uso racional de los medicamentos, contribuyendo a la equidad en salud. Se utilizaron dos enfoques: uno macro, referido al análisis del marco jurídico y a los actores de la reforma, y otro micro, relacionado a los procesos y resultados en el sistema de provisionamiento de medicamentos. Se estudiaron los instrumentos legales que dan soporte a la política farmacéutica y fue evaluada su aplicación, utilizando indicadores y una enfermedad trazadora (diabetes mellitus). Aunque existe un marco jurídico que consagra el derecho al acceso de la población a servicios de salud y medicamentos esenciales, no hay una política de medicamentos integral. La mayoría de las instituciones presentan problemas para distribuir los medicamentos que pertenecen al Plan Obligatorio de Salud, un bajo porcentaje de medicamentos es obtenido sin costo y una gran parte de pacientes los adquiere en asociaciones de diabéticos o recurre a medicina alternativa. Se encontraron aspectos que desfavorecen la equidad en la cobertura en salud y la accesibilidad a medicamentos esenciales
    2002 article Brazil open access