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Sample records for buena fe dos

  1. La buena fe en la concurrencia sobre bienes inmuebles

    Directory of Open Access Journals (Sweden)

    Gastón Fernández Cruz

    1987-12-01

    Full Text Available El presente trabajo representa una apretada síntesis de la tesis titulada "El Papel de la buena fe en la transferencia de la Propiedad Inmueble". con la que el autor optó el grado de bachiller eb  Derecho en la Pontificia Universidad Católica del Perú en diciembre de 1984. Su pretensión no es otra que dejar claramente establecido el rol que representa la buena fe dentro de un sistema consensual de transferencia de la propiedad. cuando el derecho se enfrenta a una situación de excepción ante sucesivas transferencias.realizadas por un mismo sujeto.

  2. Buena fe subjetiva y buena fe objetiva. Equívocos a los que conduce la falta de claridad en la distinción de tales conceptos

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    Martha Lucía Neme Villarreal

    2009-12-01

    Full Text Available El presente escrito tiene por objeto dejar en evidencia la confusión que en cierto sector de la jurisprudencia colombiana existe entre el concepto de buena fe objetiva y el concepto de buena fe subjetiva, que ha trascendido, por demás, a una parte de la doctrina y la legislación (C. Co., art. 863, pero, sobre todo, busca advertir sobre los graves equívocos a los que dicha confusión conduce, entre los que se cuentan: asumir que la buena objetiva comprende tanto una buena fe exenta de culpa como una buena fe en la que la diligencia no resulta exigible; pretender que la regla que prohíbe el ir contra los actos propios está regida por la buena fe subjetiva y que es una manifestación de la teoría de la apariencia; pretender proteger a nombre del principio de buena fe la representación mental del deudor que cree haber cumplido, desconociendo la exigencia de la buena fe objetiva que impone desplegar un comportamiento efectivo; y apreciar de manera errónea los alcances de la presunción de buena fe; equívocos que llevan a plantear la necesidad de retomar los senderos del derecho romano, en el que el concepto originario de buena fe estuvo siempre atado al deber de comportamiento probo y leal frente a la otra parte en el contrato, es decir, a lo que hoy entendemos como buena fe objetiva y donde la exigencia de buena fe en la posesión del comprador (convicción o creencia debió ser una utilización particular de la bona fides contractual adaptada en función de la problemática posesoria, que luego se extendería a otras situaciones que se engloban hoy bajo el nombre de la teoría de la apariencia.

  3. Responsabilidad por violación de la buena fe en la sociedad por acciones simplificada

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    Nicolás Polanía Tello

    2012-12-01

    Full Text Available La sociedad por acciones simplificada –SAS–, como los demás esquemas societarios, se funda en y está informada por el principio de la buena fe. Pero a diferencia de los otros modelos, la SAS tiene concreciones particulares de la buena fe que permiten un amparo más efectivo y eficiente de los derechos de los socios y de los terceros, en la medida en que instituciones como el fraude a la ley, el perjuicio injusto a terceros, el abuso del derecho y el administrador de hecho, todos estructurados a partir de violaciones a la buena fe, permiten tramitar los eventos de responsabilidad por ilícitos atípicos y llegar incluso a desestimar por ello el atributo de la limitación de responsabilidad.

  4. La presunción de buena fe en el sistema jurídico colombiano: una regla cuya aplicación tergiversada desnaturaliza el principio

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    Martha Lucía Neme Villarreal

    2010-07-01

    Full Text Available Una de las desafortunadas consecuencias de la ausencia de una adecuada diferenciación entre los conceptos de buena fe objetiva y buena fe subjetiva es la aplicación inapropiada de la presunción de buena fe, en cuanto aquello que constituye una excepción al régimen general, esto es, que la buena fe subjetiva posesoria se presume, se ha adoptado como regla general en materia de buena fe objetiva. Una tal generalización de la presunción; desnaturaliza el principio de buena fe, pues la regla general en materia de buena fe objetiva es que el cumplimiento de los deberes de comportamiento que emanan del principio no se presume, sino que se debe probar su efectiva realización, en tanto que los estados psicológicos o las creencias, en los que se funda la buena fe subjetiva, constituyen excepciones a la regla general en cuanto se permite su presunción. El Código de Bello consagra la regla de presunción de buena fe con alcances restringidos a los eventos de buena fe subjetiva y extenderla a situaciones en las que lo aplicable es la buena fe objetiva contraría la esencia misma del principio. En materia administrativa la Constitución colombiana consagra una excepción a la regla general que rige en materia de buena fe objetiva conforme a la cual la buena fe no se presume, al permitir que opere una presunción legal en favor del particular en las gestiones que este adelante ante aquella, como medida para equilibrar las relaciones entre la administración pública y los particulares, relación que se encuentra marcada por una fuerte asimetría.

  5. LA BUENA FE COMO FUNDAMENTO DE LOS DEBERES PRECONTRACTUALES DE CONDUCTA: UNA DOCTRINA EUROPEA EN CONSTRUCCIÓN

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    Vladimir Monsalve Caballero

    2008-01-01

    Full Text Available El ordenamiento jurídico reconoce o admite que la autonomía privada sea el punto de partida y conformación del contrato, pero no hasta el punto de considerar que, así las negociaciones preliminares permitan la concreción de un contrato, este tenga un sistema propio o autónomo, que esté sujeto a los términos incluidos en el texto contractual. Por el contrario, las reglas generales del juego siguen siendo las establecidas por el marco normativo en su conjunto y por tanto comparten una necesaria adecuación del acuerdo contractual (lex privata, a las mismas. Así, el principio de buena fe se hace presente, se extiende de igual forma, en el contenido de eticidad de cada acto que deba examinarse a la luz de las circunstancias particulares, direccionando las conductas humanas y en especial los actos y contratos que gobiernan la convivencia, de tal forma que estas prescripciones generales siempre serán aplicadas, no solo al acuerdo contractual, sino que también estarán llamadas a gobernar todo el proceso tanto de formación, como el de perfeccionamiento y ejecución.

  6. VIGENCIA DEL PRINCIPIO DE LA BUENA FE EN EL DERECHO DEL TRABAJO CHILENO Validity of the principle of good faith in the Chilean labor law

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    Pedro Irureta Uriarte

    2011-01-01

    Full Text Available La buena fe es un principio general del Derecho que, en el ámbito laboral, encuentra especial aplicación en la figura del contrato de trabajo. La buena fe es predicable tanto para el trabajador como para el empleador, y se verifica en los estadios previos a la contratación, durante el desarrollo mismo del contrato, así como al momento de la extinción. El Código del Trabajo chileno, sin referirse expresamente a este principio, ha terminado incorporando sus exigencias en distintas figuras laborales; cuestión que no impide que el núcleo esencial del principio se despliegue en toda su magnitud al momento de configurar los derechos y obligaciones de cada parte.Good faith is a general principle of law which, in the workplace, finds special application in the employment contract. This principle acts both from the worker and the employer and has to be present in stages prior to recruitment, during the fulfillment of the contract and the date of termination. The Chilean Labour Code, without explicitly referring to this principle, has incorporated its work demands in different shapes. This special technique does not interfere with a direct spillover of the legal core of that principle when the legal order configures the rights and obligations of each party.

  7. Las buenas maneras y el rol masculino o femenino como dos aspectos de la competencia comunicativa en "Alice's Adventures in Wonderland"

    OpenAIRE

    Barrios Espinosa, María Elvira

    1997-01-01

    El presente artículo defiende que la adquisición de la competencia comunicativa por los niños se ha traducido tradicionalmente en que estos demuestren buenas maneras y su identidad en cuanto a pertenencia a uno u otro sexo. El análisis del discurso de un capítulo de Alice's Adventures in Wonderland (Las aventuras de Alicia en el País de las Maravillas) se presenta como un ejemplo de cómo una obra literaria del siglo XIX refleja esta idea. Además, el análisis encuentra un paralelismo entre la ...

  8. Las buenas costumbres

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    Alberto Montezuma Hurtado

    1982-04-01

    Full Text Available Casos suelen suceder en que la información del lector brilla por su solidez y su abundancia, siendo entonces inválido el interés del escritor por presentarle problemas y situaciones para su conocimiento, reflexión y buen consejo. En el caso presente, me parece que huelga todo comentario y que pintar la realidad y exponer las preocupaciones que de ella se desprenden, no sería más que una impertinencia y no quiero incurrir en ella a sabiendas de que el lector no ignora que hace mucho tiempo acabaron en Colombia las buenas costumbres.

  9. Las buenas practicas espanolas 1998

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    Nasarre y de Goicoechea, Fernando

    2000-02-01

    Full Text Available The II HABITAT Conference held at Istanbul on June 1996, adopted the Habitat Program -Global Action Plan, in within which two performance lines are especially reinforced to reach the two main goals of suitable e housing for all and sustainable human settlements: the collaboration and participation among all the levels of the government and the civil society and, the recognition of the importance of the urban policies. In this framework is addressed the International Award Best Practices for the Improvement of the Life Conditions that, sponsored by the municipality of Dubai, is celebrated every two years and is awarded to the 10 selected by an International Independent Jury. The goal of the Competition is to promote policies and strategies more effective for the sustainable development of the humanity and their settlements, through the transmission of information and knowledge on experiences and solutions proved in the practice. The obtained results in the last international competition, with 32 of the presented Practices included in the Data Base of the United Nations Good Practices, 18 classified among the 100 best (3 of them included among the 40 finalists and finally, one, among the 10 awarded (Programs for the improvement of the urban environment of Malaga, allow us to look forward with satisfaction the panorama of the urban policy in our country.La Conferencia HABITAT II celebrada en Estambul en junio de 1996 adopto el Programa Hábitat-Plan Global de Acción-, dentro del cual se refuerzan especialmente dos líneas de actuación: la colaboración y participación entre todos los niveles de gobierno y la sociedad civil y el reconocimiento de la importancia de las políticas urbanas para alcanzar los dos objetivos principales: vivienda adecuada para todos y asentamientos humanos sostenibles. En este marco se inscribe el Concurso Internacional de Buenas Practicas para la Mejora de las Condiciones de Vida que, patrocinado par la municipalidad

  10. 57Fe NIS studies of phonon DOS in superconducting FeSe{sub 0.5}Te{sub 0.5} single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Wortmann, Gerhard [Department of Physics, University of Paderborn, Paderborn (Germany); Ksenofontov, Vadim; Gasi, Teuta; Felser, Claudia [Institute of Inorganic and Analytical Chemistry, Johannes Gutenberg University, Mainz (Germany); Chumakov, Aleksandr [European Synchrotron Radiation Facility, Grenoble (France); Tsurkan, Vladimir; Deisenhofer, Joachim; Loidl, Alois [Institute of Physics, University of Augsburg, Augsburg (Germany)

    2011-07-01

    FeSe and isostructural FeSe{sub 0.5}Te{sub 0.5} could provide valuable information for the understanding of the principal mechanisms of superconductivity (SC) in the novel Fe-based superconductors. Using {sup 57}Fe nuclear inelastic scattering (NIS) we have measured the phonon-DOS in single-crystalline samples of FeSe{sub 0.5}Te{sub 0.5} parallel and perpendicular to the c-axis. A study of the phonon-DOS as function of temperature revealed a very similar temperature dependence as observed in FeSe, also no changes of the phonon-DOS above and below T{sub c} = 14.5 K. Together with results of conventional {sup 57}Fe-Moessbauer studies, we can exclude any phonon softening connected with the observed SC. Based on these results and previous studies of FeSe, we discuss the role of phonons in the mechanisms for SC in the Fe-based systems.

  11. Escuela y familia. Dos pilares fundamentales para unas buenas prácticas de orientación educativa a través de las escuelas de padres

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    Rufino Cano González

    2015-01-01

    Full Text Available Desde una nueva dimensión del hecho educativo, las buenas prácticas de Orientación Educativa han de tener su inicio allí donde el futuro ciudadano nace y recibe los primeros cuidados, atenciones, mensajes educativos y procesos de interacción y comunicación compartida, es decir, en el seno de la familia, dentro de un clima de máximo respeto, de participación, de tolerancia responsable y bien entendida, y de educación en valores por parte de todos sus miembros. En el caso que nos ocupa, el rol que juegan, tanto la escuela como la familia y, situado entre ambas, el niño, sujeto de educación, es clave y definitivo para el desarrollo dinámico de una educación completa y de alta calidad humana y cultural. Todo ello nos lleva a reflexionar, en este artículo, sobre los conceptos actuales de familia y escuela; sobre lo que la escuela espera de los padres y los padres de la escuela; sobre la necesidad de unas buenas prácticas para mejorar la formación que demandan no pocos padres; sobre la práctica orientadora que han de ejercer los docentes más allá del hecho puntual del desempeño rutinario de la función tutorial.

  12. Buenas prácticas para un turismo sostenible

    OpenAIRE

    Rainforest Alliance; Banco Interamericano de Desarrollo (BID)

    2006-01-01

    Presentación sobre el cluster de turismo sostenible. Da a conocer el concepto de buenas prácticas, implementación de buenas prácticas y por último, una guía para estructurar un plan de buenas prácticas.

  13. Fe

    National Research Council Canada - National Science Library

    Ghasemzadeh, Mohammad Ali; Abdollahi-Basir, Mohammad Hossein; Babaei, Masoomeh

    2015-01-01

    An efficient and green approach for synthesizing chromeno[2,3-b]pyridine derivatives through one-pot three-component reactions of salicylaldehydes, thiols, and malononitrile has been developed by Fe 3 O 4...

  14. Síntese de pigmentos pretos à base de Fe, Co e Cr pela rota dos precursores poliméricos Synthesis of Fe-, Co- and Cr-based black pigments by the polymeric precursor route

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    P. R. G. Gonçalves Jr

    2006-12-01

    Full Text Available Pigmentos pretos à base de Co, Fe e Cr foram sintetizados pelo método dos precursores poliméricos. Analizou-se o efeito do tratamento térmico no desenvolvimento da cor e de estabilidade dos pigmentos. O resultado da composição otimizada do pigmento foi a mistura de duas fases cristalográficas: Fe0,7Cr1,3O3 e CoCr2O4. As fases e a coloração foram desenvolvidas a 1000 °C/2 h. Após tratamento térmico em diferentes temperaturas, os pós pigmentantes foram caracterizados nos aspectos estruturais, morfológicos e colorimétricos. Pela análise de difração de raios X foi determinada a evolução cristalina do pigmento. Através de microscopia eletrônica de varredura analisou-se a morfologia dos pós pigmentantes. A determinação da área superficial específica dos pós foi feita por adsorção de nitrogênio pelo método BET. Na análise colorimétrica foram discutidas as cores dos pós pigmentantes conjuntamente à espectroscopia de absorção na região do visível.Black pigments based on Fe, Cr and Co were synthesized by the polymeric precursor method. The thermal treatment effects were analyzed on color development and stability of pigment. The optimized pigment composition results from the Fe0.7Cr1.3O3 and CoCr2O4 mixture, with appropriately development of coloration at 1000 °C/2 h. After thermal treatment at different temperatures, structural, morphologic and colorimetric aspects of the materials were characterized. By using X-ray diffraction, the crystalline evolution of the pigment was determined. Through scanning electron microscopy the powders morphology was observed. Determination of the specific surface area of powders was done by adsorption of nitrogen using the BET method. In the colorimetric analysis, the powders colors and the visible spectroscopy absorption were discussed.

  15. [Unamuno con dos hombres y una mujer en La Magdalena

    OpenAIRE

    Anónimo

    2010-01-01

    1 fot.; papel. - Retrato de grupo. Unamuno en el campo con dos hombres y una mujer en La Magdalena. Santander?. (Gelatina D.O.P. brillo densa y ligeramente desenfocada). - Procedencia: fondo Miguel de Unamuno. - Buena Conservación.

  16. Buenas prácticas de cuidados : creando procesos seguros

    OpenAIRE

    Jurado Balbuena, Juan José

    2010-01-01

    En este capítulo detallamos 5 actividades de cuidados muy frecuentes en la actividad diaria de los centros de salud. Gran parte de estas actividades es desarrollada por los profesionales de enfermería. Queremos resaltar su importante papel en facilitar una atención segura a nuestros pacientes revisando cómo conseguir buenas prácticas de cuidados en el día a día. Las úlceras por presión son prevenibles en muchos casos. Las recomendaciones, según el grado de evidencia serían: Los cambios de pos...

  17. Actitudes docentes hacia las TIC en centros de buenas prácticas educativas con orientación inclusiva

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    José M.ª FERNÁNDEZ BATANERO

    2013-01-01

    Full Text Available El presente artículo recoge los resultados de un estudio cuyo objetivo ha sido determinar las actitudes del profesorado hacia el uso e integración de las Tecnologías de la Información y Comunicación (TIC en aulas inclusivas, así como la identificación de aquellos factores que favorecen buenas prácticas educativas con apoyo de dichas tecnologías. Respecto del tipo de diseño, se trata de un estudio de casos múltiple, concretamente de dos centros educativos, de titularidad pública, de Educación Secundaria Obligatoria de la ciudad de Sevilla (España. La selección de los casos se hizo teniendo en cuenta el criterio de ser dos centros educativos de orientación inclusiva y estar catalogados por la Administración Educativa Andaluza como de «buenas prácticas». Las técnicas utilizadas para la recogida de la información han sido el cuestionario y el grupo de discusión. Los resultados señalan, por un lado, que de manera general los docentes poseen actitudes positivas hacia las TIC, especialmente el profesorado de género masculino y aquellos que cuentan con mayores posibilidades de interacción con las mismas. Por otro lado, el hecho de contar con medios materiales suficientes; dar importancia al constructivismo; adaptar las tareas y actividades a las características del alumnado; estimular el trabajo autónomo y colaborativo; y la capacidad para fomentar políticas y culturas inclusivas entre redes de centros educativos se presentan como factores importantes para desarrollar buenas prácticas educativas con apoyo de TIC.

  18. Correlação dos achados do PEATE-FE e da avaliação comportamental em crianças com deficiência auditiva

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    Natalia Ramos

    2013-08-01

    Full Text Available OBJETIVO: analisar e correlacionar os achados dos Potenciais Evocados Auditivos de Tronco Encefáico por Frequência Específica e da avaliação comportamental, por Via aérea e Via óssea, em crianças com perda auditiva sensorioneural ou mista. MÉTODO: a casuística foi composta por dez crianças com até três anos de idade, diagnosticadas com perda auditiva sensorioneural. Foram realizados os PEATE-FE nas frequências de 0.5, 1, 2 e 4 kHz e a audiometria comportamental nas mesmas frequências, tanto por via aérea como por via óssea. Os resultados dos dois procedimentos foram correlacionados afim de verificar se o PEATE-FE é capaz de predizer o status auditivo de crianças com deficiência auditiva. RESULTADOS: os resultados mostraram forte correlação entre os dois procedimento nas quatro frequências estudadas por via aérea; já na via óssea, foi encontrada forte correlação nas frequências de 0.5, 1 e 2 kHz e moderada em 4 kHz. CONCLUSÃO: os PEATE-FE estimaram a audição com forte precisão quando comparados à audiometria comportamental. Desta forma, a aplicação dos PEATE-FE possibilita a estimativa da audição até que possam ser determinados, com segurança, os limiares comportamentais na população estudada.

  19. Convivencia escolar. Un estudio sobre buenas prácticas

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    María José Caballero Grande

    2010-06-01

    Full Text Available Este trabajo de investigación se centra en la convivencia escolar y puede enmarcarse en la línea de educación para la paz.La finalidad del mismo ha sido conocer algunas peculiaridades de prácticas educativas  que fomentan la paz y la convivencia en el ámbito escolar. Para esto, se ha recogido información, mediante entrevista estructurada, en diez centros  educativos de la provincia de Granada, acogidos a la Red Andaluza  “Escuela, espacio de paz”, sobre la puesta en marcha, desarrollo y evaluación de actuaciones encaminadas hacia la cohesión del grupo, la gestión democrática de normas, la educación en valores, las habilidades socioemocionales y la regulación pacífica de conflictos.Del análisis de las entrevistas, se desprende que hay una serie de medidas y actuaciones que se llevan a cabo en los centros educativos que favorecen la buena convivencia. La necesidad de cooperación entre todos los actores intervinientes en el proceso educativo o  la importancia de sistematizar e institucionalizar el trabajo que eduque para el fomento de una cultura de paz, conforman entre otras las conclusiones a las que se llega en este estudio.

  20. Arquitectura bioclimática en un entorno sostenible: buenas prácticas edificatorias.

    OpenAIRE

    Neila González, Francisco Javier

    2011-01-01

    Los principios bioclimáticos deben aparecer como un hábito en la construcción y no como una rareza o una excepción. Por eso se debe hablar de buenas prácticas y de buena arquitectura y no de arquitectura singular.Estas buenas prácticas deben tener como objetivo la calidad del ambiente interior y la reducción de los efectos negativos sobre el entorno.Calidad del ambiente interior: condiciones adecuadas de temperatura, humedad, movimiento y calidad del aire, etc.Los efectos de los edificios sob...

  1. Land protection plan Ellicott Slough National Wildlife Refuge proposed Buena Vista addition [2004

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Land Protection Plan, as part of the Environmental Assessment, Land Protection Plan and Conceptual Management Plan for the proposed Buena Vista addition to the...

  2. Conceptual management plan Ellicott Slough National Wildlife Refuge proposed Buena Vista addition

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — 2005 Conceptual Management Plan for Ellicott Slough proposed Buena Vista addition. Content includes information of the National Wildlife Refuge System, refuge...

  3. Conceptual management plan Ellicott Slough National Wildlife Refuge proposed Buena Vista addition

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — The 289-acre Buena Vista Property consists of three parcels; one consisting of approximately 187 acres, one consisting of approximately 100 acres, and another...

  4. Malheur National Wildlife Refuge: Narrative Report: 1936: Camp Buena Vista BF-3: 2: August

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This narrative report from the Civilian Conservation Corps summarizes activities done on Camp Buena Vista. Topics include land development and maintenance, wildlife...

  5. Derecho a la buena administración electrónica

    OpenAIRE

    Sánchez Acevedo, Marco Emilio

    2015-01-01

    Existe un derecho a la “buena administración”, consagrado en la Carta de Derechos Fundamentales de la Unión Europea —Título V, sobre “Ciudadanía”; artículo 41, sobre el “Derecho a una buena Administración”— y es indudable que la “buena administración” constituye un verdadero “derecho” de los ciudadanos y una obligación de las administraciones públicas que ha calado en la legislación y en la jurisprudencia como expresión aglutinante de su buen funcionamiento y que se ha positivado en una seri...

  6. “nuevos enfoques” de las buenas prácticas de manufactura

    OpenAIRE

    Mora Huertas, Claudia Elizabeth

    2010-01-01

    Durante los últimos años, el trabajo en Buenas Prácticas de Manufactura (bpm), además de contribuir a mejorar la calidad de los productos farmacéuticos disponibles en el mercado, ha permitido realizar un avance importante en la interpretación conceptual y en la aplicación práctica del verdadero significado del aseguramiento de la calidad en la industria farmacéutica. En ese sentido, este artículo analiza los aportes que sobre este tema han tenido las buenas prácticas de ingenie...

  7. VARIABLES DOCENTES Y DE CENTRO QUE GENERAN BUENAS PRÁCTICAS CON TIC TEACHER AND SCHOOL VARIABLES THAT GENERATE GOOD PRACTICES WITH ICT

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    Pilar Colás Bravo

    2010-02-01

    Full Text Available En este artículo se presentan los resultados de un estudio de casos llevado a cabo mediante entrevistas narrativas, cuyo objetivo es identificar los factores condicionantes de las buenas prácticas con TIC. Las buenas prácticas con TIC están relacionadas con dos áreas científicas de estudio. Una referida a la integración de las TIC en los sistemas educativos y, otra ligada a procesos de innovación. En esta aportación se presenta el estado de la cuestión respecto a factores condicionantes de las buenas prácticas desde ambas perspectivas. A partir de ahí situamos el marco teórico de este trabajo desde la perspectiva del profesorado. El análisis cualitativo realizado mediante el software científico Atlas.Ti 5.0 saca a la luz variables personales y contextuales asociadas a los procesos de innovación. In this article the results of a case study carried out are presented by means of narrative interviews, whose objective is to identify the determining factors of the good practices with ICT. The good practices with ICT are related to two scientific areas of study. One, above mentioned, related to the integration of the ICT in the educational systems and, another, connected with processes of innovation. In this contribution we present the state of the question related to determining factors of the good practices from both points of view. From there we situate the theoretical framework of this work since the perspective of the teachers. The qualitative analysis carried out by means of the program AtlasTi identifies personal and contextual factors associated to the processes of innovation.

  8. Barreras para la integración de buenas prácticas con TIC. Estudio de caso.

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    Siria Padilla Partida

    2015-12-01

    Full Text Available Esta investigación analiza las barreras u obstáculos para la integración de las buenas prácticas educativas con TIC, en la segunda más grande universidad pública de México: La Universidad de Guadalajara. Se analiza el caso del Centro Universitario de Ciencias Económico Administrativas (CUCEA, el cual es uno de los 15 centros universitarios que integran la red universitaria de la UdeG. Para esta investigación fue diseñado un cuestionario cerrado, tipo rubrica, con una escala de 5 puntos que iba desde no se ha iniciado hasta consolidado, para poder identificar cuáles eran los principales obstáculos percibidos por los profesores para integrar las TIC en las prácticas educativas. El cuestionario estuvo dividido en dos partes, la primera exploraba las barreras atribuidas a la institución educativa, y la segunda, las barreras atribuidas a los profesores. El muestreo fue representativo y aleatorio, con una muestra de 210 profesores de un total de 460. Los resultados identificaron como los mayores obstáculos: La falta de incentivos para integrar las TIC en la enseñanza con 382 puntos de un total de 1055, la falta de flexibilidad curricular con 483 puntos, y por último, la falta de confianza en la educación a distancia con 583 puntos.

  9. Appendices of an appraisal for the use of geothermal energy in state-owned buildings in Colorado. Section B: Buena Vista

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, R.T.; Coe, B.A.; Dick, J.D.

    1981-01-01

    Two state-owned building complexes have been evaluated for the use of geothermal energy within the vicinity of Buena Vista: the Colorado State Reformatory south of Buena Vista and the State Highway Department Building in downtown Buena Vista. The following are included: resource assessment for the Buena Vista area, building retrofit engineering for the two buildings, economic evaluations, institutional requirements, and environmental considerations. (MHR)

  10. Silent gains: Instituto Buena Bista and art as catalyst among Curaçaoan youth.

    Science.gov (United States)

    González, Iberia Pérez

    2010-01-01

    Considering the limited opportunities and resources for creative education, artists David Bade and Tirzo Martha, along with art historian Nancy Hoffmann, developed a dynamic platform to support creative young talent on the Dutch Caribbean island of Curaçao. The aim of Instituto Buena Bista (IBB), founded in 2006, is to strengthen the arena of culture and the visual arts by offering young Curaçaoans a basic but thorough course in art education that is meant to function as a springboard to more advanced art schools. With only two years of operation, the IBB is already seeing how some of its students go to art academies abroad and participate in art contests in the Netherlands. An exploration of how the IBB is filling up a cultural void by proposing an alternative to local youth education that allows them to develop a buena bista-a new and different view of their island, their futures, and themselves.

  11. Las computadoras ¿son buenas o malas para los niños?

    Directory of Open Access Journals (Sweden)

    Revista Chasqui

    2015-01-01

    Full Text Available Se trabaja sobre un estudio del Instituo Argentino de Computación. Sobre las computadoras hay criterios opuestos unos las defienden y otros las atacan, pero lo cierto es que éstas no son ni buenas ni malas para los niños. Da a los padres y maestros advertencias sobre los riesgos. Informa sobre el programa Kidkey que ayuda a fijar el tiempo de conexión a Internet.

  12. Buenas prácticas ambientales para el consumo de papel

    OpenAIRE

    Bellver Navarro, Carmen Gemma

    2013-01-01

    Se describen someramente las características del proceso de fabricación del papel que tienen un impacto sobre el medio ambiente, así como la forma en la que se puede minimizar o mitigar ese impacto y las etiquetas ambientales que garantizan una fabricación sostenible Bellver Navarro, CG. (2013). Buenas prácticas ambientales para el consumo de papel. http://hdl.handle.net/10251/33734.

  13. Influência dos Íons Mg, Ca, Fe, Cu e Zn sobre a tensão superficial estática de soluções contendo surfatante Influence of Mg, Ca, Fe, Cu and Zn Ions on static surface tension of surfactant solutions

    Directory of Open Access Journals (Sweden)

    F.M.L. Silva

    2006-09-01

    Full Text Available O objetivo do estudo foi avaliar a influência da presença de cinco íons em uma calda de pulverização contendo o surfatante Aterbane. A tensão superficial foi analisada por meio da medição da massa de um conjunto de 25 gotas, com quatro repetições constituindo um tratamento. O trabalho foi dividido em duas etapas. Na primeira, os tratamentos foram combinados em esquema fatorial 9x5x2, sendo nove concentrações do surfatante Aterbane (0,01; 0,025; 0,05; 0,1; 0,2; 0,5; 1; 2; e 3%, cinco íons (Mg++, Ca++, Fe+++, Cu+++ e Zn+++ e duas concentrações desses elementos (10 e 100 ppm. Na segunda etapa, os tratamentos foram combinados em esquema fatorial 5x5x1, utilizandose os mesmos cinco elementos (Mg++, Ca++, Fe+++, Cu+++ e Zn+++, em cinco concentrações (1, 5, 20, 50 e 200 ppm, com apenas uma concentração do surfatante Aterbane (0,025%. Outros nove tratamentos permitiram avaliar as tensões superficiais das concentrações do surfatante (0,01; 0,025; 0,05; 0,1; 0,2; 0,5; 1; 2; e 3% sem a adição dos íons. Os resultados mostraram que houve interferência dos íons sobre as soluções, já que, com exceção do Fe+++ (na concentração de 10 e 100 ppm e do Cu+++ (na concentração de 100 ppm, todos os íons reduziram a tensão mínima alcançada e aumentaram a eficiência do surfatante, implicando benefícios à ação do surfatante e sobre as características de possíveis soluções de aplicação. Todos os íons avaliados promoveram reduções nas tensões superficiais de soluções do surfatante na concentração de 0,025%.The objective of this study was to evaluate the influence of 5 ions on a spray solution containing the surfactant aterbane. Surface tension was analyzed by measuring the mass of a set of 25 drops, with four repetitions constituting a treatment. The work was divided in two stages. In the first, the treatments were arranged in a 9x5x2 factorial design, nine Aterbane concentrations (0.01; 0.025; 0.05; 0.1; 0.2; 0

  14. Early archosauromorph remains from the Permo-Triassic Buena Vista Formation of north-eastern Uruguay.

    Science.gov (United States)

    Ezcurra, Martín D; Velozo, Pablo; Meneghel, Melitta; Piñeiro, Graciela

    2015-01-01

    The Permo-Triassic archosauromorph record is crucial to understand the impact of the Permo-Triassic mass extinction on the early evolution of the group and its subsequent dominance in Mesozoic terrestrial ecosystems. However, the Permo-Triassic archosauromorph record is still very poor in most continents and hampers the identification of global macroevolutionary patterns. Here we describe cranial and postcranial bones from the Permo-Triassic Buena Vista Formation of northeastern Uruguay that contribute to increase the meagre early archosauromorph record from South America. A basioccipital fused to both partial exoccipitals and three cervical vertebrae are assigned to Archosauromorpha based on apomorphies or a unique combination of characters. The archosauromorph remains of the Buena Vista Formation probably represent a multi-taxonomic assemblage composed of non-archosauriform archosauromorphs and a 'proterosuchid-grade' animal. This assemblage does not contribute in the discussion of a Late Permian or Early Triassic age for the Buena Vista Formation, but reinforces the broad palaeobiogeographic distribution of 'proterosuchid grade' diapsids in Permo-Triassic beds worldwide.

  15. Early archosauromorph remains from the Permo-Triassic Buena Vista Formation of north-eastern Uruguay

    Directory of Open Access Journals (Sweden)

    Martín D. Ezcurra

    2015-02-01

    Full Text Available The Permo-Triassic archosauromorph record is crucial to understand the impact of the Permo-Triassic mass extinction on the early evolution of the group and its subsequent dominance in Mesozoic terrestrial ecosystems. However, the Permo-Triassic archosauromorph record is still very poor in most continents and hampers the identification of global macroevolutionary patterns. Here we describe cranial and postcranial bones from the Permo-Triassic Buena Vista Formation of northeastern Uruguay that contribute to increase the meagre early archosauromorph record from South America. A basioccipital fused to both partial exoccipitals and three cervical vertebrae are assigned to Archosauromorpha based on apomorphies or a unique combination of characters. The archosauromorph remains of the Buena Vista Formation probably represent a multi-taxonomic assemblage composed of non-archosauriform archosauromorphs and a ‘proterosuchid-grade’ animal. This assemblage does not contribute in the discussion of a Late Permian or Early Triassic age for the Buena Vista Formation, but reinforces the broad palaeobiogeographic distribution of ‘proterosuchid grade’ diapsids in Permo-Triassic beds worldwide.

  16. Buenas plumas

    Directory of Open Access Journals (Sweden)

    Jimena Montaña Cuéllar

    2005-09-01

    Full Text Available El periodismo en Antioquia. Juan José Hoyos (selección y prólogo. Biblioteca Pública Piloto. Concejo de Medellín, Alcadía de Medellín,Secretaría de Cultura Ciudadana de Medellín, 2003. 502 págs.

  17. Buena Vecindad y Populismo: El Caribe en las Relaciones Interamericanas de 1933 a 1946

    Directory of Open Access Journals (Sweden)

    Antonio Gaztambide-Géigel

    2016-11-01

    Full Text Available Resumen La historiografía sobre la Política del Buen Vecino nos ha permitido distinguir dos períodos en las relaciones estadounidenses con América Latina entre 1933 y 1945. Se ha discutido poco, sin embargo, acerca del efecto de ese cambio sobre las políticas y en las relaciones. Tampoco se ha dicho mucho sobre las diferencias entre el contenido e impacto del Buen Vecino en el Caribe y en el resto del hemisferio. Aquí se abordan ambas dimensiones de las relaciones entre Estados Unidos y el Caribe vinculándolas a los desarrollos políticos internos en diversas sociedades de la región. Entre otras cosas, se manifiesta una tendencia a interpretar los cambios en el Caribe utilizando conceptos y teorías de los países centrales (como fascismo, comunismo, etcétera y del contexto latinoamericano (como nacionalismo, populismo, Buen Vecino, antimperialismo, etcétera. Este trabajo intenta revisar la aplicación de las teorías y conceptos, adoptar una perspectiva más comparativa y abordar cada experiencia en sus propios términos. Palabras chaves: Caribe, EUA, Relaciones Interamericanas, populismo, Política de buena vencidad. Boa Vizinhança e Populismo: o Caribe nas relações interamericanas de 1933 a 1946. Resumo A historiografia da Política de Boa Vizinhança permitiu-nos distinguir dois períodos nas relações dos EUA com a América Latina entre 1933 e 1945. Tem sido discutido pouco, no entanto, o efeito dessa mudança sobre a política e as relações. Também não disse muito sobre as diferenças entre o conteúdo e o impacto da Boa Vizinhança no Caribe e em outras partes do hemisfério. Aqui ambas as dimensões das relações entre os EUA e o Caribe serão abordadas, relacionando-as aos desenvolvimentos políticos internos em várias sociedades da região. Entre outras coisas, há uma tendência para interpretar mudanças no Caribe, utilizando conceitos e teorias dos países centrais (como o fascismo, comunismo, etc. e o contexto

  18. Conocimientos y buenas prácticas de manufactura en personas dedicadas a la elaboración y expendio de alimentos preparados, en el distrito de Los Olivos, Lima-Perú

    OpenAIRE

    Carrasco, María; Facultad de Medicina Veterinaria y Zootecnia, Universidad Peruana Cayetano Heredia. Lima; Guevara, Beder; Municipalidad Distrital de Los Olivos. Lima.; Falcón, Néstor; Facultad de Medicina Veterinaria y Zootecnia, Universidad Peruana Cayetano Heredia. Lima.

    2014-01-01

    Objetivo: Evaluar el impacto de las capacitaciones sanitarias ofrecidas por un gobierno local sobre la persistencia y aplicaciones de los conocimientos de buenas prácticas de manufactura (BPM) en 60 manipuladores de alimentos de 11 mercados y 23 restaurantes del Distrito de los Olivos. Material y Métodos: Se utilizó un test post capacitación y dos meses después de la misma y se evaluó in situ la aplicación de las BPM en el manipulador de alimentos a través de una tabla de cotejo diseñada para...

  19. Ética y estética de la conducta en los manuales de buenas maneras españoles Ética y estética de la conducta en los manuales de buenas maneras españoles

    Directory of Open Access Journals (Sweden)

    Fernando Ampudia de Haro

    2007-03-01

    Full Text Available The aim of the article is to give the reader a general idea as to established relationships between ethics and appearances in social conduct as they have appeared in various good manuals on social behaviour from medieval times to present.In relation to this, many proposals from varying viewpoints have been presented dealing with the decline of moral content in such manuals. Ultimately these manuals propose two comprehensive models concerning the relationship between ethics and appearances, refered to as aristotalian and kantian respectively.El propósito del artículo es efectuar una aproximación general al tipo de relación que se establece entre ética y estética de la conducta tal y como ésta ha sido planteada en los diferentes manuales de buenas maneras que se han publicado en España desde la Baja Edad Media hasta nuestros días. Se proponen, a partir de esos mismos manuales, dos modelos comprensivos de las relaciones entre ética y estética del comportamiento aquí denominados aristotélico y kantiano respectivamente. Por último, se presentan diversas propuestas explicativas en torno a la disolución del contenido moral de las buenas maneras en tales manuales.

  20. Educar en valores para una buena convivencia en Educación Infantil

    OpenAIRE

    Rivera Ramón, Belén

    2017-01-01

    Este Trabajo de Fin de Grado pretende mostrar la importancia que tiene una educación en valores desde la primera etapa educativa, para que haya una buena convivencia tanto dentro como fuera del aula. La propuesta didáctica que se lleva a cabo se realiza en el 2º ciclo de Educación Infantil, a través de unos cuentos y actividades, integrando dicho contenido en rutinas diarias. Que los niños y niñas adquieran ciertos valores desde sus primeras edades, les va proporcionando una actitud de aut...

  1. Problemas y buenas prácticas educativas en Lengua castellana y Literatura

    OpenAIRE

    González García, María; Caro Valverde, María Teresa; Valverde González, María Teresa

    2011-01-01

    Este material educativo expone una visión crítica de los problemas de enseñanza-aprendizaje de la Lengua y la Literatura debido a la persistencia de un currículo oculto academicista que es incompatible con las demandas actuales de la educación basada en competencias y propone como alternativa modelos de buenas prácticas educativas, en concreto el que ha sido preparado para el Bachillerato de Investigación en la Región de Murcia.

  2. Las buenas prácticas para la promoción de la parentalidad positiva

    OpenAIRE

    Molina, María Cruz; Balsells, M. Àngels; Casas Casajuana, Jéssica; Fuentes, M.; Fuentes-Peláez, Núria; Mateos Inchaurrondo, Ainoa; Mundet, Anna; Pastor Vicente, Crescencia; Ponce, Carmen; Urrea Monclús, Aida; Vaquero Tió, Eduard

    2013-01-01

    El proyecto de innovación docente que se presenta pretende introducir en los estudiantes, el concepto de promoción de la salud basada en la evidencia, mediante la revisión documental y análisis de programas. El trabajo colaborativo interuniversitario para la elaboración de instrumentos y material docente para las buenas prácticas, mediante estrategias efectivas y recursos innovadores, servirá de orientación para establecer criterios de evaluación de programas y de guía para la práctica profes...

  3. BUENAS PRÁCTICAS DE AULAS VIRTUALES EN LA DOCENCIA UNIVERSITARIA SEMIPRESENCIAL

    OpenAIRE

    Manuel Area Moreira; Mª Belén San Nicolás Santos; Elena Fariña Vargas

    2010-01-01

    En este artículo presentamos el diseño y resultados de un estudio realizado en la Universidad de La Laguna (ULL) destinado a identificar buenas prácticas de aulas virtuales en la docencia universitaria desarrolladas bajo la modalidad de blended learning o enseñanza semipresencial. El estudio se desarrolló en el primer trimestre del año 2008 y analizó una importante muestra de las aulas virtuales (N= 107) existentes en el Campus Virtual de dicha universidad en el periodo 2005-07. Se seleccion...

  4. Construyendo buenos ciudadanos con buenas prácticas en salud: dengue e influenza AH1N1 en Cali, Colombia

    Directory of Open Access Journals (Sweden)

    Alejandro Arango

    2013-06-01

    Full Text Available Este artículo discute la relación entre la dimensión biológica de las enfermedades y los hábitos de auto-cuidado o “conductas saludables”. Su pregunta central indaga por cómo un fenómeno aparentemente biológico genera ciertas “buenas prácticas” en torno a la salud, defendiendo la idea de la enfermedad como un asunto socio-cultura, más que un mero hecho biológico. El estudio aquí presentado se apoya en una investigación realizada en la ciudad de Cali y enfocada en dos enfermedades, dengue e influenza AH1N1, entre 2009 y 2010. El examen de la relevancia adquirida por estas dos dolencias, mostrará cómo la biología y las prácticas de auto-cuidado tienen una estrecha relación entre sí.

  5. INDICADORES Y CRITERIOS DE CALIDAD DE BUENAS PRÁCTICAS COEDUCATIVAS. UNA PROPUESTA INNOVADORA

    Directory of Open Access Journals (Sweden)

    Francisco Javier Saavedra Macías

    2013-01-01

    Full Text Available Este trabajo se plantea en el marco del proyecto Teon XXI sobre uso de las TIC aplicadas a la coeducación. En este contexto nuestro objetivo es la elaboración de una escala observacional para evaluar buenas prácticas coeducativas, que sirva de complemento a las metodologías cualitativas habitualmente utilizadas. El instrumento se compone de cinco criterios o indicadores de calidad (eficacia, efecto transformador, sostenibilidad, legitimidad, replicabilidad definidos en base a conceptos clave que articulan una graduación a intervalos oscilante entre 0 y 4. Los resultados de la aplicación por cuatro jueces a diez prácticas seleccionadas de centros escolares andaluces por su relevancia coeducativa mostraron su adecuada fiabilidad. Concluimos la conveniencia del proceso mismo de construcción de este tipo de escalas como vehículo para la reflexión sobre el concepto de buena práctica, dada su multidimensionalidad y complejidad de definición. Asimismo, se recomienda el análisis desagregado de los distintos criterios para su evaluación.

  6. Aeropalinología de la ciudad de Yerba Buena, provincia de Tucumán (Argentina)

    OpenAIRE

    García, María Elena

    2010-01-01

    Aeropalinología de la ciudad de Yerba Buena, provincia de Tucumán (Argentina). Durante los años 1999 - 2002 se llevó a cabo la primera caracterización aerobiológica de la ciudad de Yerba Buena. El muestreo atmosférico se realizó con un captador gravimétrico de tipo Durham. El análisis de las muestras permitió la identificación de 46 tipos polínicos. Los granos de polen más relevantes en el muestreo son de especies cultivadas como Cupressaceae, Morus sp., Broussonetia sp., Fraxinus...

  7. BUENAS PRÁCTICAS DE AULAS VIRTUALES EN LA DOCENCIA UNIVERSITARIA SEMIPRESENCIAL

    Directory of Open Access Journals (Sweden)

    Manuel Area Moreira

    2010-02-01

    Full Text Available En este artículo presentamos el diseño y resultados de un estudio realizado en la Universidad de La Laguna (ULL destinado a identificar buenas prácticas de aulas virtuales en la docencia universitaria desarrolladas bajo la modalidad de blended learning o enseñanza semipresencial. El estudio se desarrolló en el primer trimestre del año 2008 y analizó una importante muestra de las aulas virtuales (N= 107 existentes en el Campus Virtual de dicha universidad en el periodo 2005-07. Se seleccionaron seis ejemplos de aulas virtuales, clasificados por campos científicos, caracterizadas por la incorporación de recursos de información, de comunicación y de aprendizaje experiencial.

  8. Astronaut David Brown talks with team members from Lake Buena Vista, Fla

    Science.gov (United States)

    2000-01-01

    Astronaut David Brown chats with members of the Explorers team, from Lake Buena Vista, Fla., during the FIRST (For Inspiration and Recognition of Science and Technology) Southeast Regional competition held March 9-11 in the KSC Visitor Complex Rocket Garden. Teams of high school students from all over the country are testing the limits of their imagination using robots they have designed, with the support of business and engineering professionals and corporate sponsors, to compete in a technological battle against other schools' robots. Of the 30 high school teams competing at the Southeast Regional event, 16 are Florida teams co-sponsored by NASA and KSC contractors. Local high schools participating are Astronaut, Bayside, Cocoa Beach, Eau Gallie, Melbourne, Melbourne Central Catholic, Palm Bay, Rockledge, Satellite, and Titusville.

  9. BUENAS PRÁCTICAS APLICADAS A LA IMPLEMENTACION COLABORATIVO DE APLICATIVOS WEB

    Directory of Open Access Journals (Sweden)

    Manuel Guillermo García Sandoval

    2016-02-01

    Full Text Available RESUMEN La implementación de buenas prácticas para el desarrollo de software, son una compilación de métodos o técnicas que permiten llevar a cabo de manera óptima el conjunto de actividades que comprenden el desarrollo de un sistema de información. En el campo de desarrollo de software colaborativo, estas prácticas son empleadas con el fin de que las actividades realizadas por cada miembro de un equipo de trabajo, y esté tengan concordancia con las actividades realizadas por los demás miembros. Esto se realiza mediante el seguimiento de las normas correspondientes, que al ser implementadas, generan un proyecto comprensible por quienes conforman el equipo de trabajo. El no seguimiento de las mismas, puede generar retrasos e incluso fracaso en un proyecto de desarrollo colaborativo, debido qué al no establecer una metodología específica para la solución de un problema, cada miembro del equipo puede tomar diferentes caminos para la solución del mismo, pudiendo las discrepancias entre los mismos, provocar futuros problemas de compatibilidad dentro del sistema a implementar. Este proyecto pretende llevar a cabo el establecimiento de una metodología de desarrollo, que involucre una serie de actividades para la implementación colaborativa de un aplicativo web en el entorno colaborativo cloud9, basada en las buenas prácticas, con la posterior aplicación y evaluación de la misma, de acuerdo con los resultados obtenidos.

  10. Alimentación de dos especies de anfibios (Anura: Hylidae en la estación de bajas temperaturas y su relación con la acumulación de energía en Santa Fe, Argentina Feeding of two amphibian species (Anura: Hylidae during the low temperatures season and its relationship with energy storage in Santa Fe, Argentina

    Directory of Open Access Journals (Sweden)

    Carolina Elizabet Antoniazzi

    2013-06-01

    Full Text Available Existe escasa información sobre la alimentación de las especies de anfibios activas durante la estación fría o las estrategias de utilización de reservas lipídicas como fuente de energía durante el periodo de bajas temperaturas. Por lo tanto, se analizaron las estrategias de obtención y acumulación energética durante la estación de bajas temperaturas en un anfibio que se reproduce principalmente en otoño-invierno, Hypsiboas pulchellus (Hp, y uno que lo hace en primavera-verano, Dendropsophus nanus (Dn. Para ello se analizó la alimentación de ambas especies y se utilizó el peso de los cuerpos grasos (CG como indicador del desarrollo de las reservas energéticas. Si bien se encontró una elevada similitud en la dieta entre las especies, esto no implicó la ausencia de diferencias en las estrategias de obtención energética entre ellas. El bajo índice de vacuidad gastrointestinal de Hp, acompañado de CG poco desarrollados, permite señalar que, para sostener la elevada demanda energética de la actividad reproductiva concentrada en el otoño-invierno, esta especie continúa alimentándose aún en temperaturas bajas. Por otro lado, el índice de vacuidad de Dn fue mayor al de Hp, mientras que sus CG se encontraron bien desarrollados, por lo que esta especie utilizaría en mayor medida sus reservas lipídicas como fuente de energía para transitar el período de bajas temperaturas y llegar en buenas condiciones a la temporada reproductiva en la próxima primavera-verano.In environments with thermal and pluvial seasonality such as those of the Middle Paraná River floodplain (Province of Santa Fe, Argentina, most amphibian species reproduce during the warm season and drastically diminish their activity during winter. Even though, a few species remain active during the cold season, such as Hypsiboas pulchellus that has its reproductive peak during the autumn-winter period (and the consequent energy demand. The objective of this study

  11. Sam Harris La promoción del humanismo exige el fin de la fe

    Directory of Open Access Journals (Sweden)

    Javier Monserrat Monserrat

    2015-01-01

    Full Text Available El tipo de ateísmo de San Harris es distinto del de otros autores porque se funda exclusivamente en la ponderación de la fe religiosa irracional como fuente de la violencia, del terror, del enfrentamiento social —interior a las naciones e internacional— que acaba por hacer imposible toda forma de cohesión social. Es evidente que Harris da por descontado que las creencias religiosas son irracionales y esto por dos razones. Primero porque la razón, en la ciencia y en la filosófica, no puede aducir argumento alguno para pensar que Dios o los dioses sean reales y existentes. Segundo porque las afirmaciones mismas de las religiones presentan un contenido que, por las buenas, no se puede creer, repugna inmediatamente a la razón, como puedan ser, por ejemplo, hablar de una «encarnación» de Dios o de que Mahoma ascendió al Cielo a lomos de un caballo alado, y otras afirmaciones de similar irracionalidad.

  12. VARIABLES DOCENTES Y DE CENTRO QUE GENERAN BUENAS PRÁCTICAS CON TIC TEACHER AND SCHOOL VARIABLES THAT GENERATE GOOD PRACTICES WITH ICT

    National Research Council Canada - National Science Library

    Pilar Colás Bravo; Juan Casanova Correa

    2010-01-01

    En este artículo se presentan los resultados de un estudio de casos llevado a cabo m ediante entrevistas narrativas, cuyo objetivo es identificar los factores condicionantes de las buenas prácticas con TIC. Las buenas prácticas con TIC...

  13. Identificación de factores críticos para implantar buenas prácticas agrícolas

    Directory of Open Access Journals (Sweden)

    Nelson Gutiérrez Guzmán

    2009-09-01

    Full Text Available En este artículo se presenta la identificación de los factores críticos (FC que afectan la implantación de un programa de buenas prácticas agrícolas (BPA en productores de café y frutas del departamento del Huila, en Colombia, mediante la realización de un análisis factorial exploratorio utilizando como método de factorización el análisis de componentes principales (ACP; las ma- trices de datos se construyeron con los resultados de la aplicación de sendos instrumentos con estructura definida en las dos po- blaciones objeto de estudio, el instrumento Starbucks C.A.F.E. Practices –para pequeños caficultores en el caso de los producto- res de café– y EUREPGAP V2.1 Oct.2004 – Checklist-listado de verificación para frutas y hortalizas, aplicado a los productores de fruta. Los resultados de esta investigación permitieron la identificación de seis FC que deben de ser tenidos en cuenta al im- plantar un programa de BPA: infraestructura, actividades propias del proceso de producción establecido, toma y mantenimiento de registros, conciencia medioambiental, bienestar y seguridad de los trabajadores, y control de la calidad.

  14. BUENAS PRÁCTICAS, UNA SOLUCIÓN PARA UN MEJOR DESARROLLO DE SOFTWARE

    Directory of Open Access Journals (Sweden)

    Liliana del Carmen Ramírez-M

    2014-12-01

    Full Text Available Este articulo tiene como objetivo principal dar a conocer una serie de buenas prácticas planteadas para un mejor desarrollo de software, basadas en las metodologías agiles más representativas se han propuesto unos valores, unas características, unos roles, unas prácticas y un ciclo de vida para el desarrollo de un proyecto de software, con lo cual se busca abarcar todo el proceso desde que surge una necesidad por parte de un cliente, hasta el momento en se tiene la seguridad de que el cliente está totalmente satisfecho con el producto. Estas prácticas planteadas buscan comprometer al equipo de trabajo e integrarlo al proyecto de una manera beneficiosa para las personas participantes, ya que pueden estar desde el inicio hasta la fase final del proyecto cumpliendo un rol u otro específicamente, logrando con esto reducción de tiempo, costos y otros.

  15. ITINERARIOS DE LA BUENA ENSEÑANZA A PARTIR DE LOS RELATOS BIOGRÁFICOS DOCENTES

    Directory of Open Access Journals (Sweden)

    Zelmira Álvarez

    2010-01-01

    Full Text Available En la investigación cualitativa en educación, el enfoque biográfico y narrativo ha logrado su identidad propia. Siguiendo esta línea, se indaga aquí, por medio de entrevistas semi-flexibles, en las biografías de una selección de buenos docentes de la Facultad de Humanidades de la Universidad Nacional de Mar del Plata, Argentina. Éstos fueron identificados a través de cuestionarios semi-abiertos administrados a estudiantes avanzados de los Profesorados de esta Facultad. Del análisis de las conversaciones, se han seleccionado seis casos que confieren a sus recorridos de vida públicos y privados la acepción de itinerarios físicos o intelectuales. La interpretación de los datos transforma a estos relatos en historias de vida y sugiere el entretejido de las buenas prácticas con las trayectorias. Se construye así en la educación superior -donde la enseñanza en el aula es privada- un conocimiento local pero colegiado.

  16. BUENAS PRÁCTICAS TIC. LA ALFABETIZACIÓN DIGITAL EN MAYORES

    Directory of Open Access Journals (Sweden)

    Félix Huelves Martín

    2010-12-01

    Full Text Available Los equipos informáticos y sus periféricos están diseñados para el uso de un único usuario, constan de un único teclado, ratón; y de una única pantalla. De modo que en una clase de iniciación a la informática, la mejor opción parece ser un equipo por persona. Así, aparentemente, al interactuar individualmente se avanzará más. ¿Pero, y si no es posible contar con suficientes medios? ¿Es realmente imprescindible el “monopuesto” para lograr un aprendizaje significativo? Gracias a la experiencia durante varios cursos de alfabetización digital con adultos utilizando una metodología afín a los objetivos expondremos una buena práctica formativa, haciendo frente a factores adversos como la escasez de recursos. Sin lugar a dudas, sin descuidar la psicología del adulto, educando la adquisición de capacidades tecnológicas haciendo a la persona autónoma en su aprendizaje.

  17. EL BIENESTAR SUBJETIVO ANTE LAS BUENAS PRÁCTICAS EDUCATIVAS CON TIC: SU INFLUENCIA EN PROFESORADO INNOVADOR

    Directory of Open Access Journals (Sweden)

    Jesús Valverde Berrocoso

    2013-01-01

    Full Text Available El objetivo de este estudio, que forma parte de una investigación más amplia sobre la innovación educativa y la integración de las Tecnologías de la Información y la Comunicación (TIC en el aula [1], es conocer el grado de «bienestar subjetivo» autopercibido por profesorado innovador y asociado a su realización de «buenas prácticas educativas con TIC». El bienestar subjetivo es un concepto que se extrae de las percepciones de las personas sobre su existencia o su visión subjetiva de su experiencia vital y profesional. En una muestra de profesorado innovador (N=41 de centros educativos seleccionados por sus «buenas prácticas con TIC», se aplicó un cuestionario para medir qué motivaciones, emociones y competencias están presentes en una práctica innovadora con tecnologías, así como el grado de satisfacción personal y profesional logrado tras la aplicación de estas buenas prácticas. Los resultados revelan las motivaciones que mueven al profesorado a implicarse en actividades docentes innovadoras, las percepciones de satisfacción y las emociones en las que se fundamenta su grado de bienestar subjetivo vinculado con las buenas prácticas educativas con TIC. Las motivaciones que impulsan la innovación o las buenas prácticas educativas con TIC son de carácter práctico (mejora del trabajo docente y mayor interés del alumnado, ético (deber y responsabilidad de uso por parte del profesorado y personal (superación de retos para lograr una mayor competencia digital. El profesorado manifiesta mayoritariamente emociones positivas relacionadas con el uso educativo de las TIC (orgullo, satisfacción, autoestima, autoconfianza y felicidad, autopercepción de logro de metas profesionales y una mayor eficacia en su actividad docente. El profesorado percibe que sus buenas prácticas inciden en la actitud positiva de sus compañeros hacias las innovaciones con TIC, el apoyo del equipo directivo hacia estos proyectos y a una mayor

  18. UNA APROXIMACIÓN AL CONOCIMIENTO DE UNA PROFESORA UNIVERSITARIA, AGENTE DE BUENAS PRÁCTICAS DOCENTES, UTILIZANDO MAPAS CONCEPTUALES

    Directory of Open Access Journals (Sweden)

    Fermín González García

    2010-01-01

    Full Text Available Se muestra en este trabajo un modelo de conocimiento construido sobre buenas prácticas docentes de una profesora universitaria, responsable de la asignatura "Circuitos y Sistemas I", correspondiente al primer curso (y primer cuatrimestre de la titulación de Ingeniería Técnica de Telecomunicación: Sonido e Imagen. El modelo fue realizado en el marco de una investigación que se ha llevado a cabo por 6 universidades españolas. El trabajo identifica, analiza, explicita y representa con la ayuda del programa informático CMap Tools el pensamiento pedagógico y la práctica docente de un profesor universitario caracterizado por su buena práctica, a partir de entrevistas en profundidad. El modelo de conocimiento construido de las buenas prácticas de este profesor, fácilmente accesible a través de Internet, constituye un excelente ejemplo que puede orientar tanto al profesor novel como a profesores experimentados que quieran mejorar la calidad de la docencia que imparten.

  19. Ética de la investigación. Las buenas prácticas

    Directory of Open Access Journals (Sweden)

    López de la Vieja, M.ª Teresa

    2008-04-01

    Full Text Available The Act 14/2007 regulates biomedical research, including research with stem cells and cloning for therapeutic purposes. The Spanish legislation about those controversial topics could also exemplify the changing perspective about ethical codes and ethical committees, because now they are not only centered on rights, and guarantees for the subjects involved in experimentation, but on good practice. Research Ethics has usually been related to norms, and especially to respect for human rights in the biomedical field. From the Nurmberg Code, the Helsinki Declaration, the Oviedo Convention to the Addition Protocol on biomedical research, the perspective of rights prevailed over a wider perspective, which now aims to promote the researchers’ commitment and their responsibilities to health and welfare; the welfare of every subject, humans, and non-humans, and in every context, including the developing countries. The UNESCO Declaration could expand this perspective, including social justice issues in the agenda of research Ethics, usually centered on autonomy, as basic principle, and on the human rights approach. The article would analyze the good practice approach, with guidelines expanding the agenda of research Ethics in order to promote a better governance of scientific practice.La Ley 14/2007 regula la investigación biomédica, incluida la investigación con células troncales y la clonación con fines terapéuticos. La legislación española sobre estos temas tan controvertidos puede ejemplificar también ciertos cambios en el enfoque sobre códigos éticos y comités de Ética; ahora éstos no sólo se centran en los derechos y las garantías para los sujetos participantes en la experimentación, sino también en las buenas prácticas. La Ética de la investigación ha estado casi siempre asociada con las normas y, en especial, con el respeto por los derechos humanos en el ámbito de la Biomedicina. Desde el Código de Nürnberg, la Declaraci

  20. INTERPRETATION OF GRAVITY SURVEYS IN GRASS AND BUENA VISTA VALLEYS, NEVADA

    Energy Technology Data Exchange (ETDEWEB)

    Goldstein, N.E.; Paulsson, B.

    1977-12-01

    Continuing the LBL study of geothermal exploration techniques and the assessment of potential reservoirs begun in 1974, detailed gravity surveys were made in the vicinity of Leach Hot Springs, Grass Valley, and Kyle Hot Springs, Buena Vista Valley, in northern Nevada. The terrain-corrected Bouguer gravity values were gridded, corrected for regional gradients (Grass Valley only) bya least squares polynomial fit to the data, and then processed by means of an inversion scheme to yield a contour map of the basement configuration. The three-dimensional inversion algorithm assumes a two-layer earth of variable first layer thickness but constant density contrast between layers. Although a fit to observed data can be obtained for a range of density contrasts, a contrast of 0.06 g/cm{sup 3} gave interpreted results most consistent with results from other geophysical data: (a) agreement between the minimum thickness contours and the margins of exposed Paleozoic rocks and Cretaceous intrusives; (b) agreement between the calculated basement depth and report information from a deep drill hole in Grass Valley; and (c) agreement between estimated basement depths and interpretation of seismic reflection-refraction data. To illustrate the information value of the depth-to-basement calculations, we show comparisons of gravity, electrical resistivity, and seismic interpretations along selected profile lines. Gravity and seismology gave nearly identical results for the location and dip of the Hot Springs fault in Grass Valley. The gravity interpretation agreed reasonably well with that of the electrical basement, although the electrical basement is consistently 200-400 meters deeper than the density or velocity interface.

  1. Separation and radiometric determination of {sup 59}Ni, {sup 63}Ni, {sup 55}Fe, {sup 99}Tc and {sup 94}Nb in radioactive wastes of low and intermediate activities from PWR nuclear power plants; Separacao e determinacao radiometrica dos radionuclideos {sup 59}Ni, {sup 63}Ni, {sup 55}Fe, {sup 99}Tc e {sup 94}Nb em rejeitos radioativos de baixa e media atividades provenientes de centrais nucleares do tipo PWR

    Energy Technology Data Exchange (ETDEWEB)

    Temba, Eliane Silvia Codo

    2016-10-01

    The objective of this work was the development and establishment of a specific analytical protocol for the determination of the {sup 59}Ni, {sup 63}Ni, {sup 55}Fe, {sup 99}Tc and {sup 94}Nb radionuclides in low and intermediate radioactive waste samples of Almirante Alvaro Alberto Nuclear Power Plant, CNAAA, located in the city of Angra dos Reis, RJ. The separation and purification techniques used have taken into account the particularities of each radionuclide studied. Chemical separation methods were used, as well as carriers and radioisotope tracers, and ion-exchange and extraction chromatography involving specific resins. The main techniques used for the analysis and determination of the radionuclides were Liquid Scintillation Counting (LSC) and Gamma Spectrometry. Also used were Atomic Emission Spectroscopy with Inductively Coupled Plasma (ICP-AES) and Neutron Activation Analysis (NAA) for the chemical yield determination. Concerning to the {sup 59}Ni, {sup 63}Ni, {sup 55}Fe radionuclides, the methodology of sequential separation proved to be very appropriate for their separation and determination, as could be observed by the results obtained. Chemical yields in the range from 39 to 100%, and LSC counting efficiencies in the range of 37.8% for {sup 55}Fe, and 71.5% for {sup 63}Ni, are in accordance with the results found in the literature. The spectra of LSC showed that the methodology used to separation and purification of these radionuclides was very successful. The results for {sup 59}Ni have shown that the use of a {sup 55}Fe certified standard for calibration of the equipment was a viable alternative. In the case of the {sup 99}Tc radionuclide the use of rhenium as carrier and chemical yield monitor, resulted in high chemical yields. Use of Gamma Spectrometry analysis made it possible to check that the main interfering agents were actually removed with the combined use of anion exchange chromatography and TEVA resin. The chemical yield of {sup 94}Nb was

  2. Algunas experiencias para la difusión de buenas prácticas docentes en la enseñanza universitaria.

    Directory of Open Access Journals (Sweden)

    Carla Costa Sanz

    2011-11-01

    Full Text Available El presente escrito es una reseña del libro Buenas prácticas docentes en la universidad. Modelos y experiencias en la Universidad de Barcelona, que pretende dar a conocer el análisis de diversos proyectos que versan sobre la mejora de la docencia universitaria con el objetivo final de difundir unas buenas prácticas docentes en el marco de la enseñanza superior.

  3. Playing-Related Problems among Musicians of the Orquesta Buena Vista Social Club® and Supporting Bands.

    Science.gov (United States)

    Heredia, Luisn; Hinkamp, David; Brodsky, Marc; Llapur, Carlos

    2014-06-01

    The Orquesta Buena Vista Social Club® is a world-renowned group of Cuban musicians accomplished in a variety of musical styles. The musicians of the Orquesta Buena Vista Social Club and supporting musicians of their orchestras represent a cohort of musicians throughout Cuba who continue to play traditional genres and perform into their older ages. The purpose of the study was to (1) identify musculoskeletal conditions that occurred over the previous 12 months among the members of the Orquesta and supporting musicians and (2) to discover if these conditions, in part, were caused by or in some way affected musical performance. The study was a convenience sample of musicians within the Orquesta Buena Vista Social Club and supporting musical groups. Thirty-six musicians completed a self-administered survey. Sixty-seven percent (24/36) of the total sample of musicians and 89% (16/18) of those over age 60 years had at least one musculoskeletal condition over the previous 12 months. Forty-four percent (16/36) of the total sample of musicians and 61% (11/18) of those older than 60 years of age reported that a musculoskeletal complaint was either, in part, caused by or affected their performance. Musculoskeletal conditions were prevalent among the Cuban musicians, especially in those over 60 years of age. Collaboration of medical professionals, managers, and musicians may help to generate ideas on how to prevent injuries as well as to evaluate what treatments for playing-related conditions, including both conventional and complementary and alternative therapies, are most effective.

  4. Propuesta de buenas prácticas de educación virtual en el contexto universitario

    Directory of Open Access Journals (Sweden)

    Carlos Ruiz Bolívar

    2016-01-01

    Full Text Available En este trabajo se desarrolla una propuesta de buenas prácticas docentes para facilitar procesos formativos de calidad a través de aulas virtuales en un contexto universitario. Se identificaron 18 buenas prácticas pedagógicas, clasificadas y organizadas en un proceso esencialmente instruccional que incluye las fases: (a la planificación didáctica previo al inicio de la formación; (b el desarrollo didáctico de la formación, con las subfases de actividades de inicio y ejecución; y (c el cierre técnico y administrativo de dicho proceso. La propuesta está validada por los resultados de estudios evaluativos reportados por los autores sobre sus propias experiencias individuales o en conjunto como docentes de cursos online universitarios y con base en la aplicación de un modelo tecno-pedagógico propio. Se fundamenta en las teorías del aprendizaje: constructivismo sociocultural, cognoscitivismo de procesamiento de informacion y el enfoque conectivista. Se concluye que el e-Learning, canalizado por vía de aulas virtuales, es una modalidad educativa con un gran potencial para la formación en el contexto de la sociedad de la información y del conocimiento, en general, y en la universidad en particular, sobre la base de docentes implicados en la ejecución de buenas prácticas en el desarrollo de sus labores didácticas y tutoriales.

  5. Promover la justicia y la vida buena a escala global. El liberalismo político de Martha Nussbaum

    Directory of Open Access Journals (Sweden)

    Gabriel Arjona Pachón

    2009-01-01

    Full Text Available ¿Tiene algún sentido en el mundo actual abogar por una propuesta política liberal? El texto responde esta pregunta a través de la presentación de las ideas centrales que caracterizan el liberalismo político de Martha Nussbaum, como una teoría cuya meta axial es la promoción de las capacidades de cada individuo para elegir su propia concepción de la vida buena.

  6. La dinamización de la biblioteca escolar: buenas prácticas y recursos educativos

    OpenAIRE

    Santos Díaz, Inmaculada Clotilde

    2017-01-01

    El objetivo de esta comunicación es mostrar la importancia de las actividades de dinamización de la biblioteca escolar como motor de impulso de actividades de enseñanza y aprendizaje y del fomento de la lectura. Para ello, se mostrará una selección de buenas prácticas de bibliotecas de centros educativos de enseñanza primaria y secundaria partiendo desde la celebración de efemérides y actividades puntuales hasta la integración de proyectos documentales. Entre las actividades cabe destaca...

  7. Análisis de una buena alimentación en los alumnos de Educación Primaria

    OpenAIRE

    Sánchez Cancillo, Adrián

    2015-01-01

    La importancia que tiene una buena alimentación en el periodo escolar es vital para un desarrollo físico y emocional del niño. El presente Trabajo hace referencia a los hábitos alimenticios, en concreto al hábito alimentario infantil, llevado a cabo por los niños y guiada por sus progenitores, durante su etapa escolar. En primer lugar se presenta una investigación sobre la alimentación habitual del alumnado de Educación Primaria. Para ello se ha llevado a cabo un sondeo que busca averigua...

  8. BUENAS PRÁCTICAS Y PROGRAMAS EXTRAORDINARIOS DE ATENCIÓN AL ALUMNADO EN RIESGO DE EXCLUSIÓN EDUCATIVA

    Directory of Open Access Journals (Sweden)

    Juan Manuel Escudero Muñoz

    2009-01-01

    Full Text Available En los últimos años, las buenas prácticas se han convertido en una perspectiva teórica y práctica aplicada a diversos ámbitos de las políticas sociales y educativas contra la exclusión. De forma singular también se ha desarrollado en relación con la vulnerabilidad y la exclusión educativa. Tras revisar algunas aproximaciones y hacerse eco de sus posibilidades y limitaciones teóricas y prácticas, el artículo propone un modelo marco que identifica diversos niveles y dimensiones del concepto de buenas prácticas en relación con las concepciones, las políticas y las prácticas de respuesta al alumnado en riesgo de exclusión educativa. Para finalizar se propone una Guía con diferentes categorías y elementos que puede servir para la investigación y la discusión sobre las medidas extraordinarias de atención a la diversidad en la Educación Secundaria Obligatoria dentro del sistema educativo español.

  9. Evaluation of Pb and Fe tenors present in the sediments nearby the activities of taking advantage of lead-acid batteries; Avaliacao dos teores de Pb e Fe presentes nos sedimentos proximos as atividades de reaproveitamento de baterias chumbo-acidas

    Energy Technology Data Exchange (ETDEWEB)

    Soares, Fernanda; Andrade, Crescencio; Monteiro, Carlos; Oliveira, Daniela; Valentim, Eliane, E-mail: candrade@cnen.gov.b, E-mail: valentim@cnen.gov.b [Centro Regional de Ciencias Nucleares (CRCN/NE-CNEN/PE), Recife, PE (Brazil)

    2011-07-01

    The region chosen for this study was the Municipality of Belo Jardim, Pernambuco State, Brazil, which is considered an important industrial complex of the production and repairing of lead-acid batteries. Sediment samples were collected near to the illegal smelting industries and analyzed by ionic exchange method using a alpha-beta proportional counter for determining the activity of Pb-210, radionuclide used as geochronological tool. The chemical elements Pb and Fe were determined by means of flame atomic absorption spectrometry. The obtained results indicated an expressive increasing of lead and iron concentrations in the last 20 years. The concentrations in the sampled profile varied from 318 to 15487 mg.kg-1 and from 19 to 1524 mg.kg-1 for Fe and Pb, respectively. (author)

  10. Microstructure of two phases alloy Al{sub 3}Ti/Al{sub 3}Ti{sub 0.75}Fe{sub 0.25}; Microestructura de una aleacion de dos fases Al{sub 3}Ti/Al{sub 3}Ti{sub 0.75}Fe{sub 0.25}

    Energy Technology Data Exchange (ETDEWEB)

    Angeles, C.; Rosas, G.; Perez, R. [Instituto Nacional de Investigaciones Nucleares, Departamento de Sintesis y Caracterizacion de Materiales, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1998-07-01

    The titanium-aluminium system presents three intermetallic compounds from those Al{sub 3}Ti is what less attention has received. The objective of this work is to generate and characterize the microstructure of multiphase alloys nearby to Al{sub 3}Ti compound through Fe addition as alloying. This is because it has been seen that little precipitates of Al{sub 2}Ti phase over Al{sub 3}Ti intermetallic compound increases its ductility. (Author)

  11. Síntese de ferrita NiFe2O4 e sua incorporação em compósitos de poliamida 6: Parte 1: caracterização estrutural por drx e mev dos pós e dos compósitos Synthesis of NiFe2O4 ferrite and its incorporation in nylon 6: Part 1: structural characterization by xrd and sem of ferrite powders and its composites

    Directory of Open Access Journals (Sweden)

    Daniella C. Bezerra

    2010-01-01

    Full Text Available As ferritas geralmente são absorvedoras de radiação eletromagnética e apresentam a versatilidade de poderem ser manufaturadas com geometrias diferentes, e usadas na forma de ferritas policristalinas (corpo sinterizado ou de compósitos de ferrita (adição de pó em matriz apropriada. A poliamida 6, por sua vez, pertence a uma classe de polímeros atraentes para aplicações em engenharia devido à combinação de propriedades como: estabilidade dimensional, boa resistência ao impacto sem entalhe e excelente resistência química. O objetivo deste trabalho foi sintetizar pós de ferrita NiFe2O4, e avaliar a adição destes em concentrações de 10, 30, 50 e 60% em massa a uma matriz polimérica de poliamida 6 usando um misturador da Haake Blücher, para obter compósitos de poliamida 6/NiFe2O4. Os pós e os compósitos foram caracterizados por difração de raios X (DRX e microscopia eletrônica de varredura (MEV. Os difratogramas de raios X mostraram picos característicos da poliamida 6 e da ferrita. Por MEV foi observada a formação de aglomerados grandes para a concentração de 60% e, uma grande quantidade de poros. Para a concentração de 10%, as partículas ficaram mais dispersas, com menos aglomerados e menos poros no compósito.Ferrites normally absorb electromagnetic radiation, being versatile in that they can be manufactured in different geometries and used as polycrystalline ferrites (sintered body or composites of ferrite (with addition of the powder to an appropriate matrix. On the other hand, nylon 6 is an attractive polymer for engineering applications due to the combination of properties such as dimensional stability, good impact strength without notch indentation and excellent chemical resistance. The aim of this paper was to synthesize ferrite (NiFe2O4 powders and to evaluate their addition in concentrations of 10, 30, 50 and 60 wt% into a nylon 6 polymer matrix using a Haake Blücher mixer. The powders and the

  12. “Buen o buena docente” desde la perspectiva de estudiantes que han egresado de educación secundaria

    Directory of Open Access Journals (Sweden)

    Robert Caballero-Montañez

    2006-09-01

    Full Text Available “Buen o buena docente” es aquella persona que ha marcado e influido de manera trascendental en la vida personal y académica de sus estudiantes y cuya imagen permanece en su memoria escolar como un recuerdo prolongado y altamente positivo. En consecuencia, conocer cuáles son sus rasgos centrales y por qué impactaron de tal manera en sus estudiantes merece ser más investigado como un aporte al campo de estudio sobre la docencia en educación básica. En este marco, el objetivo central de esta investigación empírica ha sido analizar las características del “buen o buena docente” desde la percepción de sujetos egresados de educación secundaria de escuelas públicas y privadas de Lima (Perú. Los resultados de este estudio cualitativo, basado en entrevistas semiestructuradas a ocho estudiantes que han egresado, ha permitido describir, por un lado, los rasgos del buen personal docente en relación a su alumnado, caracterizado por un estilo vinculante expresado en el compromiso con este, en una percepción positiva y actitud motivadora y una calidad afectiva en la interacción profesorado-alumnado; y, por otro lado, rasgos en relación con su profesión como: su pasión por enseñar; su dominio sobre contenidos y la organización de la clase. El estudio concluye que el hecho que todos los egresados y egresadas hayan podido recordar al menos a un profesor o profesora como buen o buena docente revela la heterogeneidad de tipos de docentes que exige superar generalizaciones negativas y que la imagen docente es una construcción colectiva en varias promociones. Una de las implicaciones de este estudio es recuperar la voz de los exalumnos y exalumnas, tanto para el campo de las investigaciones como en el de la política educativa, por contener un valioso potencial para mejorar nuestra comprensión de la experiencia escolar y de la relación docente-estudiantes.

  13. Estudio comparativo de buenas prácticas para la recolección de la evidencia digital

    OpenAIRE

    Armilla, Nicolás; Eterovic, Jorge; Panizzi, Marisa D.; Torres, Luis

    2017-01-01

    Este trabajo de investigación consiste en la comparación de un conjunto de buenas prácticas para la recolección de la evidencia digital. En la República Argentina se evidenciaba la ausencia de un manual, un procedimiento o de un código sobre la recolección de la evidencia digital. Esto conllevo a que una gran cantidad de casos quedasen inconclusos y sin resolución, hasta la creación de la Guía de obtención, preservación y tratamiento de evidencia digital de la Procuración General de la Nación...

  14. Dos traducciones costarricenses de Guy de Maupassant

    Directory of Open Access Journals (Sweden)

    Alejandro Alvarado Quirós

    2016-09-01

    Full Text Available La historia de la traducción literaria en Costa Rica ya tiene buena documentación académica que corrobora su desarrollo y su persistencia. Desde los años tempranos del siglo xx, no pocos escritores dedicaron su pluma, a modo de oficio paralelo, tanto a su creación literaria como a la traducción. Sin duda alguna, porque las obras que tradujeron significaban, en buena medida, sus verdaderos modelos de escritura, pero también porque como traductores, entendieron desde temprano que misión suya era también verter al español, y para Costa Rica, obras que de otro modo difícilmente se conocerían con prontitud en el medio. Un insigne escritor costarricense de aquella etapa inicial de las letras nacionales fue Alejandro Alvarado Quirós (1876-1945, autor de crónicas, crítica literaria y ensayos de singular interés. Como escritor asociado al modernismo costarricense, fue asiduo lector de las letras francesas de la segunda mitad del siglo xix, y varios de los grandes narradores del realismo y el simbolismo francés fueron sus preferidos. En 1912 reunió en el pequeño tomo titulado Lilas y resedas (Imprenta Alcina, San José varios cuentos franceses, especialmente del ilustre cuentista Guy de Maupassant. De esa colección se han extraído dos, para esta sección de Letras: «Nuestras cartas» y «Adiós», que pulcramente Alvarado Quirós vertió al español; desde luego, un español culto, al modo del discurso modernista, como conscientemente el traductor ejecutó su labor. Como Alvarado Quirós, no pocos modernistas se vieron seducidos por el oficio de traducir: Roberto Brenes Mesén, Ricardo Fernández Guardia, Fabio Baudrit, José Fabio Garnier. Fue una empresa que se fue convirtiendo en tarea obligada y, con el tiempo, en una especie de tradición solapada, que hasta nuestros días se extiende.

  15. POLÍTICAS EDUCATIVAS, BUENAS PRÁCTICAS Y TIC EDUCATIONAL POLICIES AND GOOD PRACTICES WITH ICT IN ANDALUSIA REGION

    Directory of Open Access Journals (Sweden)

    Juan de Pablos Pons

    2010-02-01

    Full Text Available Esta aportación está vinculada a la difusión de los resultados de un proyecto de investigación titulado “Políticas educativas autonómicas y sus efectos sobre la innovación pedagógica en el uso de las TIC en los centros escolares”, que se ha desarrollado en el marco del Plan Nacional de I+D 2004-2007. El trabajo se centra en el análisis del discurso que explicita las políticas educativas en Andalucía, dirigidas a la incorporación de las TIC en el sistema educativo. El estudio realizado permite, por un lado, conocer y detallar los conceptos implícitos en las mismas respecto a “buenas prácticas” con TIC, innovación educativa con TIC, y usos de las TIC, y por otro, determinar los principales  ámbitos de incidencia de la intervención política, así como los programas de incentivación relacionados con la innovación y buenas prácticas con TIC.This contribution is linked to a research project entitled "Education policies and their effects on regional educational innovation in the use of ICT in schools", which has been developed under the National Program Research and Development 2004-2007. The work is focused on discourse analysis about incorporating Andalusian ICT in the educational system. The study allows to understand the concepts involved in the same relation to good practice with ICT education with ICT innovation and ICT use, and to determine the main areas where the political intervention and incentive programs related to innovation and good practice with ICT.

  16. SEGURIDAD ALIMENTARIA Y NUTRICIONAL EN LA REGIÓN CARIBE: CONSECUENCIAS DE LA DESNUTRICIÓN Y BUENAS PRÁCTICAS COMO SOLUCIONES

    Directory of Open Access Journals (Sweden)

    Sofía Lissbrant

    2015-01-01

    Full Text Available Este trabajo presenta tres Buenas Prácticas que pueden brindar soluciones a la situación alarmante de inseguridad alimentaria y desnutrición que existe en la región Caribe colombiana, a pesar de tener alta potencialidad de producción de alimentos. Para identificar las Buenas Prácticas se indagaron a cerca de 400 profesionales de entidades públicas, privadas y ONG. Esa encuesta reveló tres ejemplos destacados de Buenas Prácticas que, con métodos distintos, generaron cambios positivos en la Seguridad Alimentaria y Nutricional de los habitantes de Sucre y Cesar. Adicionalmente, se sugirió que las tres Buenas Prácticas pueden ser replicadas y con poca dificultad incorporadas en los Planes de Desarrollo Departamentales. Si las iniciativas identificadas cuentan con el apoyo de los tomadores de decisiones, tienen potencial para fortalecer a los pequeños productores, reducir la inseguridad alimentaria y mejorar el estado nutricional de la población.

  17. Variants, Layers of Authorial Intervention, and Texts in Lope de Vega’s La buena guarda and La encomienda bien guardada autograph manuscript

    Directory of Open Access Journals (Sweden)

    Stefania Capoia

    2014-01-01

    Full Text Available In this article I study, analyze and classify the variant readings and the different layers of authorial intervention that appear in Lope de Vega’s La buena guarda and La encomienda bien guardada manuscript. I contend that the second version of the work should be edited, a possibility thus far neglected by modern editors.

  18. Los deberes derivados de la buena fe como límite al poder de dirección del cabeza de red

    OpenAIRE

    Gómez Asensio, Carlos

    2013-01-01

    Las redes empresariales constituyen una forma de organización empresarial conocida y estudiada desde el ámbito de la economía, las ciencias de la organización empresarial y el management. Sin embargo, esta forma de organización empresarial no ha despertado el interés de los juristas hasta hace relativamente poco tiempo. La causa de este fenómeno es debido a que, en un principio, los operadores económicos que comenzaron a estructurar su actividad en forma de red empresarial, lo hicieron emp...

  19. Sociologia dos desastres

    OpenAIRE

    Ribeiro, Manuel João

    1995-01-01

    Este artigo apresenta uma conceptualização dos desastres como processos não rotineiros de cunho socialmente relevante. Na primeira parte, reflectir-se-á sobre as dinâmicas de articulação entre o sistema social e o ambiente construído, como processos configurativos das causas sistémicas dos desastres. Na segunda parte, serão abordados os conceitos de vulnerabilidade social, culturas de desastres e as dinâmicas de desenvolvimento que enquadram analiticamente as dimensões sociais dos desastres. ...

  20. A cidade dos outros

    Directory of Open Access Journals (Sweden)

    Ernesto Venturini

    2009-08-01

    Full Text Available Os percursos costumeiros dentro da cidade em que vivemos desenham nosso "mapa da cidade". A tipologia deste mapa depende fundamentalmente de nosso nível social. Examinou-se, anteriormente, o mapa da cidade dos pacientes que saíram do hospital psiquiátrico, para avaliar os efeitos da desinstitucionalização. Hoje, examina-se como vive o clandestino dentro das cidades italianas. O mapa do clandestino se baseia na degradação; evidencia mecanismos de intolerância e de acolhida; permite entender como as pessoas se enrijecem em suas posições ou, ao contrário, como as identidades dos sujeitos interagem e favorecem mudanças e emancipação. A escolha se funda na disponibilidade dos sujeitos e é fortemente influenciada pelas políticas públicas de respeito dos direitos das pessoas.

  1. Buenas prácticas docentes en la formación del profesorado: Relatos y modelos entramados

    Directory of Open Access Journals (Sweden)

    Zelmira Álvarez

    2011-01-01

    Full Text Available Este trabajo da cuenta de algunos aspectos de la labor cumplida por el Grupo GIEEC, Facultad de Humanidades, Universidad Nacional de Mar del Plata, Argentina. La línea de investigación seguida se describe como naturalista, interpretativa, con una aproximación biográfico-narrativa. Se procede a laidentificación de los buenos docentes mediante un cuestionario a estudiantes avanzados de todos los profesorados de la Facultad, aportando las características de las mejores clases vividas. Los docentes más nombrados como ejemplos de buena enseñanza son entrevistados en profundidad y sus relatos interpretados a la luz de categorías teóricas que nos ayudan a repensar los fundamentos y las prácticas de formación del profesorado. Es nuestra intención presentar aquí el caso de un buen docente del Profesorado de Inglés planteando entrecruzamientos, continuidades y discontinuidades entre las narrativas de los alumnos sobre sus buenos docentes y las de estos últimos sobre sus trayectorias, mentores y alumnos ideales.

  2. Estudios de caso sobre buenas prácticas para superar el conflicto en el Valle del Cauca

    Directory of Open Access Journals (Sweden)

    Luis Fernando Barón Porras

    2009-06-01

    Full Text Available Desde la perspectiva establecida por el Banco de Buenas Prácticas para Superar el Conflicto, creado por el Programa de las Naciones Unidas para el Desarrollo, este artículo presenta sintéticamente una investigación que ha examinado cinco experiencias que reflejan este tipo de prácticas en el Valle del Cauca. Los casos estudiados incluyen la organización de población desplazada, el fortalecimiento de un gobierno local, la difusión de información a través de la televisión, y el desarrollo de programas académicos y de proyectos sociales para jóvenes agricultores. Además de la descripción de los casos, este informe de investigación presenta un resumen del contexto en el que ocurren las cinco experiencias y reflexiona sobre las lecciones y recomendaciones que surgen de un análisis comparativo de ellas.

  3. Secretos de la Buena Vida: processes of dietary change via a tailored nutrition communication intervention for Latinas.

    Science.gov (United States)

    Baquero, Barbara; Ayala, Guadalupe X; Arredondo, Elva M; Campbell, Nadia R; Slymen, Donald J; Gallo, Linda; Elder, John P

    2009-10-01

    Secretos de la Buena Vida was a successful tailored nutrition communication intervention delivered to Latinas living along the US-Mexico border in California. The intervention was delivered over a 14-week period and consisted of three intervention conditions: weekly home visits with promotoras + weekly tailored mailed newsletters in the first condition, weekly tailored mailed newsletters in the second condition and targeted materials in the attention control condition. The current study examined what elements of the promotora + tailored newsletter and tailored newsletter-only conditions were most effective for behavioral adoption and maintenance in a sample of 238 Latina women. Process evaluation measures assessed the implementation, fidelity and dose of these two intervention conditions. Results indicate that there was high fidelity to program implementation and delivery. Perceived effort, perceived support and intervention length predicted adoption of a lower fat diet at the 15-month follow-up. In the promotora + tailored newsletter condition, married women were four times more likely to be adopters of dietary fat changes than single women. These findings highlight the importance of process evaluation measures and help us understand the mechanism by which tailored print materials and interpersonal health communication via promotoras can facilitate health behavior change.

  4. Anharmonic phonons and magnons in BiFeO3

    Energy Technology Data Exchange (ETDEWEB)

    Delaire, Olivier A [ORNL; Ma, Jie [ORNL; Stone, Matthew B [ORNL; Huq, Ashfia [ORNL; Gout, Delphine J [ORNL; Brown, Craig [National Institute of Standards and Technology (NIST); Wang, Kefeng [Nanjing National Laboratory of Microstructures, Nanjing University, Nanjing; Ren, Zhifeng [Boston College, Chestnut Hill

    2012-01-01

    The phonon density of states (DOS) and magnetic excitation spectrum of polycrystalline BiFeO3 were measured for temperatures 200 < T < 750K , using inelastic neutron scattering (INS). Our results indicate that the magnetic spectrum of BiFeO3 closely resembles that of similar Fe perovskites, such as LaFeO3, despite the cycloid modulation in BiFeO3. We do not find any evidence for a spin gap. A strong T-dependence of the phonon DOS was found, with a marked broadening of the whole spectrum, providing evidence of strong anharmonicity. This anharmonicity is corroborated by large amplitude motions of Bi and O ions observed with neutron diffraction. These results highlight the importance of spin-phonon coupling in this material.

  5. La cultura organizacional y su influencia en las buenas prácticas para la gestión del conocimiento en las Pymes de Colombia

    Directory of Open Access Journals (Sweden)

    CARLOS EDUARDO MARULANDA ECHEVERRY

    Full Text Available El objetivo del presente trabajo es la exposición de la relación existente entre la cultura organizacional y las buenas prácticas para la gestión del conocimiento en las Pymes de Colombia, la cual parte de un modelo de evaluación de gestión del conocimiento que fue aplicado a 321 empresas. Para el efecto, se utilizaron métodos de análisis y síntesis y un tipo de estudio descriptivo exploratorio y correlacional. Se concluye que la cultura modera de forma positiva y significativa las buenas prácticas para la gestión de conocimiento. Este estudio se espera que aporte al desarrollo de las pequeñas y medianas empresas del país para formular acciones que permitan potenciar su crecimiento.

  6. Buenas prácticas en el ámbito educativo y su orientación a la gestión del conocimiento

    Directory of Open Access Journals (Sweden)

    Doris Jerí Rodríguez

    2008-12-01

    Full Text Available El artículo aporta diversas aproximaciones sobre uno de los conceptos que ha ido cobrando fuerza en la literatura educativa interesada en reconocer los avances de las escuelas: las buenas prácticas. Para ello el texto contribuye, sobre la base de la bibliografía actual, a rescatar las definiciones y alcances de este enfoque centrado en las buenas prácticas educativas. El artículo logra además presentar las contribuciones de este enfoque en el ámbito de la gestión del conocimiento en las organizaciones educativas y, en particular, se presentan sus aportes en relación con la gestión del proceso de enseñanza-aprendizaje.

  7. BUENAS PRÁCTICAS EN LOS PROGRAMAS EXTRAORDINARIOS DE ATENCIÓN A LA DIVERSIDAD EN CENTROS DE EDUCACIÓN SECUNDARIA. UNA MIRADA DESDE LA EXPERIENCIA

    Directory of Open Access Journals (Sweden)

    Antonio Luzón

    2009-01-01

    Full Text Available El presente trabajo se enmarca dentro de un proyecto I+D+I Estudiantes en riesgo de exclusión educativa en la ESO: situación, programas y buenas prácticas del que está dando cuenta este Monográfico. Tiene como objetivo general analizar las políticas educativas, las prácticas y los resultados que se están alcanzando con aquellos estudiantes que encuentran dificultades acusadas de seguir el currículo y la enseñanza regular en la ESO y que están, por tanto en situación extrema de riesgo de exclusión educativa y social. Este artículo, que se inicia con una breve conceptualización teórica del concepto de buenas prácticas, presenta el análisis de los casos tanto de la Comunidad Autónoma de Murcia como de Andalucía, concretamente, a partir de entrevistas en profundidad y observaciones de aulas, analizadas desde la perspectiva de buenas prácticas. En concreto, se pone de manifiesto qué acciones, estrategias y metodologías alimentan las tareas que se llevan a cabo en institutos de educación secundaria con alumnado en riesgo de exclusión social. Son definidas y consideradas como buenas prácticas por sus resultados, sistematización, valoración, aceptación y difusión social y educativa.

  8. Variables asociadas a buena calidad de vida en pacientes con enfermedad renal crónica secundaria a nefropatía diabética

    National Research Council Canada - National Science Library

    Oropeza-Guzmán, Eric; Santana-Cano, Adriana Lorena; García-Cárdenas, Mario Alberto; Sandoval-Magaña, Mónica Araceli

    2012-01-01

    ... demográficas, socioeconómicas, físicas y familiares significativamente asociadas a buena CVRS, en pacientes hispanos con enfermedad renal crónica secundaria a nefropatía diabética. Se ha realizado en la Unidad de Medicina Familiar No. 51 del Instituto Mexicano del Seguro Social en Guadalajara, México. Mediante un muestreo no probabilístico por cuota, ...

  9. GÉNERO Y EDUCACIÓN FÍSICA. ANÁLISIS DE BUENAS PRÁCTICAS COEDUCATIVAS

    Directory of Open Access Journals (Sweden)

    Joaquín Piedra

    2013-01-01

    Full Text Available Este trabajo, dentro del proyecto de investigación TEON XXI, analiza y describe buenas prácticas de Educación Física con perspectiva de género. Aplicamos la teoría sociológica de doing gender al desarrollo de criterios sobre cómo construir una nueva cultura de género en las escuelas, implicando los planos socioculturales, relacionales e individuales en un microanálisis etnográfico. Se interpreta el ajuste entre dichas prácticas y las necesidades del contexto educativos en que tienen lugar. Se investigan cuatro modelos de prácticas, la selección muestral es de tipo teórico, aplicando una estrategia de máxima variación apoyado en un proceso de vagabundeo y localización en bola de nieve de informantes y ejemplos claves; proceso que culmina con la selección, grabación y análisis de los casos ilustrativos. Se utilizan indicadores concretos y contextualizados para a la interpretación analítica, tales como: eficacia, efecto transformador, sostenibilidad, legitimidad y replicabilidad. El trabajo de campo implica analizar fuentes documentales, así como registros de observaciones participantes y entrevistas en profundidad a expertos/as, mediante análisis de contenido. Los resultados permiten dotar al profesorado de ejemplos, pero también aportar criterios, modelos e indicadores para que el profesorado pueda reflexionar sobre la calidad y bondad de sus prácticas considerando determinadas circunstancias contextuales y necesidades específicas.

  10. Análisis de impacto y potencial de transferibilidad de Buenas Prácticas latinoamericanas

    Directory of Open Access Journals (Sweden)

    Susana Simón Tenorio

    2014-06-01

    Full Text Available ResumenLa escala y el rápido proceso de urbanización de América Latina suponen un reto para las políticas urbanas. El trabajo analiza la tipología, los agentes implicados y los resultados de las políticas urbanas desarrolladas desde la Conferencia de Estambul (1996 de cara a establecer un proceso de reflexión previo a la Conferencia Hábitat III que se celebrará en 2016. Para ello se han identificado  las ciudades más exitosas en el Concurso de Buenas Prácticas y se ha analizado el impacto de las experiencias y su adecuación con los problemas urbanos.Palabras clavePrograma Hábitat, indicadores urbanos, políticas urbanas, Belo Horizonte, Córdoba, Medellín, Montevideo, Santiago de Chile.AbstractThe size, as well as the fast urbanisation process in Latin-América, mean a challenge for Urban Policies. This paper analyses the typology, the skate-holders involved and the results of the developed urban policies since "The Istanbul Conference" in 1996. This is in order to establish a reflection process before the "Habitat Conference III" which will be held in 2016. To that effect, the most successful cities from the Good Practices Competition have been analysed as well as the impact of these experiences and their adequacy to the urban problems. KeywordsHabitat Program, urban indicator, urban policies, Belo Horizonte, Córdoba, Medellín, Montevideo, Santiago de Chile.

  11. Horticultura periurbana: Implementación de un programa de “buenas prácticas” en Pilar

    Directory of Open Access Journals (Sweden)

    Luciana Galván

    2010-07-01

    Full Text Available La producción de verduras que se realiza en la periferia exterior del Área Metropolitana de Buenos Aires (AMBA constituye una actividad esencial a la hora de asegurar el abastecimiento alimentario cotidiano de 13 millones de habitantes. El trabajo se propone sistematizar la experiencia de implementación de un programa que se está llevando a cabo actualmente con 74 productores que se localizan en el partido de Pilar, uno de los más afectados por el avance de la urbanización. El mismo, denominado PRO.A.A.S. (Promoción de la Actividad Agropecuaria Sustentable, se ha instituido durante 2007 a través de un convenio formalizado entre la Municipalidad de Pilar y el Instituto Nacional de Tecnología Agropecuaria. Tiene como propósito que los horticultores, en su gran mayoría de origen boliviano, mejoren sus procedimientos a través de “buenas prácticas” tecno-productivas. El trabajo pretende determinar en qué medida este tipo de experiencias interpelan al investigador sobre los modos de la urbanización en una metrópolis como Buenos Aires considerando que el periurbano, un espacio de interfase urbano-rural, constituye un territorio “de borde”, con la carga simbólica y las dificultades de abordaje metodológico que su situación “transicional” trae aparejada.

  12. ¿es razonable la fe religiosa? sentido y sinsentido de una pregunta

    OpenAIRE

    Stroop, Constantin Stroop

    2010-01-01

    ¿Es razonable ser religioso? ¿Es razonable la fe religiosa? Este ensayo desea examinar estas preguntas y, por cierto, de modo literal. No pretendo encontrar buenas respuestas, sino analizar las preguntas mismas, pues debo confesar que no comprendo del todo su sentido o, en palabras más precisas, la forma en que tales preguntas son examinadas hoy en día ante todo por la filosofía analítica de la religión, ya que tal examen me resulta irritante.2 A continuación quiero exponer algunas reflexione...

  13. Groundwater and surface-water interaction and potential for underground water storage in the Buena Vista-Salida Basin, Chaffee County, Colorado, 2011

    Science.gov (United States)

    Watts, Kenneth R.; Ivahnenko, Tamara; Stogner, Sr., Robert W.; Bruce, James F.

    2014-01-01

    By 2030, the population of the Arkansas Headwaters Region, which includes all of Chaffee and Lake Counties and parts of Custer, Fremont, and Park Counties, Colorado, is forecast to increase about 73 percent. As the region’s population increases, it is anticipated that groundwater will be used to meet much of the increased demand. In September 2009, the U.S. Geological Survey, in cooperation with the Upper Arkansas Water Conservancy District and with support from the Colorado Water Conservation Board; Chaffee, Custer, and Fremont Counties; Buena Vista, Cañon City, Poncha Springs, and Salida; and Round Mountain Water and Sanitation District, began a 3-year study of groundwater and surface-water conditions in the Buena Vista-Salida Basin. This report presents results from the study of the Buena Vista-Salida Basin including synoptic gain-loss measurements and water budgets of Cottonwood, Chalk, and Browns Creeks, changes in groundwater storage, estimates of specific yield, transmissivity and hydraulic conductivity from aquifer tests and slug tests, an evaluation of areas with potential for underground water storage, and estimates of stream-accretion response-time factors for hypothetical recharge and selected streams in the basin. The four synoptic measurements of flow of Cottonwood, Chalk, and Browns Creeks, suggest quantifiable groundwater gains and losses in selected segments in all three perennial streams. The synoptic measurements of flow of Cottonwood and Browns Creeks suggest a seasonal variability, where positive later-irrigation season values in these creeks suggest groundwater discharge, possibly as infiltrated irrigation water. The overall sum of gains and losses on Chalk Creek does not indicate a seasonal variability but indicates a gaining stream in April and August/September. Gains and losses in the measured upper segments of Chalk Creek likely are affected by the Chalk Cliffs Rearing Unit (fish hatchery). Monthly water budgets were estimated for

  14. BUENAS PRÁCTICAS TIC. LA ALFABETIZACIÓN DIGITAL EN MAYORES GOOD PRACTICE TIC. DIGITAL LITERACY IN OLDER

    Directory of Open Access Journals (Sweden)

    Félix Huelves Martín

    2010-12-01

    Full Text Available Los equipos informáticos y sus periféricos están diseñados para el uso de un único usuario, constan de un único teclado, ratón; y de una única pantalla. De modo que en una clase de iniciación a la informática, la mejor opción parece ser un equipo por persona. Así, aparentemente, al interactuar individualmente se avanzará más. ¿Pero, y si no es posible contar con suficientes medios? ¿Es realmente imprescindible el “monopuesto” para lograr un aprendizaje significativo? Gracias a la experiencia durante varios cursos de alfabetización digital con adultos utilizando una metodología afín a los objetivos expondremos una buena práctica formativa, haciendo frente a factores adversos como la escasez de recursos. Sin lugar a dudas, sin descuidar la psicología del adulto, educando la adquisición de capacidades tecnológicas haciendo a la persona autónoma en su aprendizaje.Computer equipment and their peripherals are designed for use by a single user, there is only one keyboard, only one mouse, and of course, a single screen. Therefore in the moment to provide a literacy class, the best option seems to be one computer per person. So each student seemed to learn more, have greater interaction with media, and therefore more learning time. But, Is it possible to have the number of computer needed for each student, always? Is it really essential the Single Computers in classroom for effective learning? Thanks to the experience in lot of adults´ literacy courses, using a methodology consistent with the goal of learning, we show a good formative experience, which although obvious, it allows us to realize factors such as the shortage of technological resources, adult psychology and the need to educate not only new technological capabilities but also to transmit values essential to ease management in the knowledge society.

  15. Spatial-Temporal Distribution of Hantavirus Rodent-Borne Infection by Oligoryzomys fulvescens in the Agua Buena Region--Panama.

    Science.gov (United States)

    Armién, Blas; Ortiz, Paulo Lazaro; Gonzalez, Publio; Cumbrera, Alberto; Rivero, Alina; Avila, Mario; Armién, Aníbal G; Koster, Frederick; Glass, Gregory

    2016-02-01

    Hotspot detection and characterization has played an increasing role in understanding the maintenance and transmission of zoonotic pathogens. Identifying the specific environmental factors (or their correlates) that influence reservoir host abundance help increase understanding of how pathogens are maintained in natural systems and are crucial to identifying disease risk. However, most recent studies are performed at macro-scale and describe broad temporal patterns of population abundances. Few have been conducted at a microscale over short time periods that better capture the dynamical patterns of key populations. These finer resolution studies may better define the likelihood of local pathogen persistence. This study characterizes the landscape distribution and spatio-temporal dynamics of Oligoryzomys fulvescens (O. fulvescens), an important mammalian reservoir in Central America. Information collected in a longitudinal study of rodent populations in the community of Agua Buena in Tonosí, Panama, between April 2006 and December 2009 was analyzed using non-spatial analyses (box plots) and explicit spatial statistical tests (correlograms, SADIE and LISA). A 90 node grid was built (raster format) to design a base map. The area between the nodes was 0.09 km(2) and the total study area was 6.43 km(2) (2.39 x 2.69 km). The temporal assessment dataset was divided into four periods for each year studied: the dry season, rainy season, and two months-long transitions between seasons (the months of April and December). There were heterogeneous patterns in the population densities and degrees of dispersion of O. fulvescens that varied across seasons and among years. The species typically was locally absent during the late transitional months of the season, and re-established locally in subsequent years. These populations re-occurred in the same area during the first three years but subsequently re-established further south in the final year of the study. Spatial

  16. Spatial-Temporal Distribution of Hantavirus Rodent-Borne Infection by Oligoryzomys fulvescens in the Agua Buena Region - Panama

    Science.gov (United States)

    Gonzalez, Publio; Cumbrera, Alberto; Rivero, Alina; Avila, Mario; Armién, Aníbal G.; Koster, Frederick; Glass, Gregory

    2016-01-01

    Background Hotspot detection and characterization has played an increasing role in understanding the maintenance and transmission of zoonotic pathogens. Identifying the specific environmental factors (or their correlates) that influence reservoir host abundance help increase understanding of how pathogens are maintained in natural systems and are crucial to identifying disease risk. However, most recent studies are performed at macro-scale and describe broad temporal patterns of population abundances. Few have been conducted at a microscale over short time periods that better capture the dynamical patterns of key populations. These finer resolution studies may better define the likelihood of local pathogen persistence. This study characterizes the landscape distribution and spatio-temporal dynamics of Oligoryzomys fulvescens (O. fulvescens), an important mammalian reservoir in Central America. Methods Information collected in a longitudinal study of rodent populations in the community of Agua Buena in Tonosí, Panama, between April 2006 and December 2009 was analyzed using non-spatial analyses (box plots) and explicit spatial statistical tests (correlograms, SADIE and LISA). A 90 node grid was built (raster format) to design a base map. The area between the nodes was 0.09 km2 and the total study area was 6.43 km2 (2.39 x 2.69 km). The temporal assessment dataset was divided into four periods for each year studied: the dry season, rainy season, and two months-long transitions between seasons (the months of April and December). Results There were heterogeneous patterns in the population densities and degrees of dispersion of O. fulvescens that varied across seasons and among years. The species typically was locally absent during the late transitional months of the season, and re-established locally in subsequent years. These populations re-occurred in the same area during the first three years but subsequently re-established further south in the final year of the

  17. O ecologismo dos pobres

    Directory of Open Access Journals (Sweden)

    Juan Martinez ALIER

    1997-12-01

    Full Text Available O ecologísmo tem colocado em cheque as leis capitalistas de mercado, principalmente na sua fase globalizada, devido à apropriação e exploração inconsequente dos recursos naturais. Ao mesmo tempo tem apontado que o meio ambiente não se reduz ao tratamento somente cientifico da natureza. O presente artigo ressalta aspectos importantes do ecologísmo como a participação das mulheres, o marxismo, o neo-narodnismo, etc. e é rico em exemplos de problemas ambientais decorrentes das relações de produção. O ecologísmo dos pobres é apontado como uma perspectiva necessária às lutas ambientais no Terceiro Mundo.

  18. O Jardim dos Sonhos

    Directory of Open Access Journals (Sweden)

    RAUL CÂNOVAS

    2010-06-01

    Full Text Available O jardim dos sonhos sempre foi um ideal dos homens. No Antigo Egito, já se falava em um jardim sempre verde para onde as pessoas de bom coração iam após a morte. E na mitologia grega, um lindo jardim era palco das festas bucólicas dos deuses. As grandes religiões também citavam jardins como paraísos, como o Jardim do Éden. Neste artigo, Raul Cânovas nos leva a refletir sobre o sentido de um “jardim perfeito”, sem tratar a perfeição como apenas plástica e estruturada com exatidão, mas referindo-se a um jardim que nos inspire e emocione, emancipado de modismos passageiros. O paisagista também nos alerta sobre as condições mutáveis de um jardim, que nunca está finalizado. O paisagismo não é apenas técnica; é também sensibilidade, utilidade, sustentabilidade e equilíbrio das forças da natureza.

  19. Buena concordancia de un método acortado para determinación de anticuerpos IG M antidengue

    OpenAIRE

    García,María

    2005-01-01

    El diagnóstico serológico del dengue cuenta con métodos de ELISA cuyo procesamiento demora como mínimo 5 horas, siendo necesaria la estandarización de métodos para reducir estos tiempos, sin afectar su sensibilidad y la especificidad. Se midió la concordancia de los resultados de dos métodos de ELISAIgM para el diagnóstico serológico de dengue.

  20. Buena sangre y hábitos españoles: repensando a Alonso de Silva y Diego de Torres

    Directory of Open Access Journals (Sweden)

    Joanne Rappaport

    2012-01-01

    Full Text Available Este artículo explora la frontera porosa entre mestizos e indígenas en el Nuevo Reino de Granada durante el siglo XVI, interrogándose sobre cómo los mestizos aspirantes a los cacicazgos muiscas se presentaron a sí mismos y cómo fueron caracterizados por sus adversarios en la negociación de sus relaciones con la corona española, los encomenderos locales y sus propios vasallos. La reflexión se centrará, en particular, en dos hombres: don Alonso de Silva, cacique de Tibasosa, y don Diego de Torres, cacique de Turmequé; ambos hijos de mujeres pertenecientes a líneas de sucesión de los cacicazgos muiscas, pero que fueron criados en hogares paternos españoles. Las pretensiones de estos dos personajes sobre los cacicazgos contradecían las aspiraciones de otros mestizos de élite de su tiempo, quienes buscaban aceptación en la sociedad española de Santafé y Tunja. En contraste, los dos se describían sistemáticamente a sí mismos como candidatos  privilegiados para lograr el estatus de miembros de la élite indígena, recurriendo a marcadores de identidad cristianos e ibéricos.

  1. Terapia asistida por caballos: nueva propuesta de clasificación, programas para personas con discapacidad intelectual y buenas prácticas

    OpenAIRE

    Arias, Víctor; Arias, Benito; Morentin, Raquel

    2008-01-01

    El propósito de este artículo es presentar una alternativa al método de clasificación tradicionalmente utilizado en el ámbito de las terapias ecuestres, alternativa en la que, siguiendo los avances en materia de clasificación en discapacidad, se sustituye el criterio “tipo de discapacidad” por el criterio “necesidades concretas” y “deseos y metas” de la persona que acude al servicio de terapia asistida por caballos. Otro de los propósitos es contrastar las buenas y malas prácticas que afectan...

  2. Buenas prácticas de intervención social en relación al ocio con jóvenes en riesgo de exclusión desde la percepción de los agentes sociales (Good practices of social intervention in relation to leisure with young people at risk of exclusion from the perception of social agents

    Directory of Open Access Journals (Sweden)

    Fátima Poza-Vilches

    2017-11-01

    Full Text Available Este artículo plantea delimitar buenas prácticas en el trabajo con jóvenes socialmente vulnerables desde la caracterización de la intervención profesional, en materia de ocio. Para ello se plantea un estudio descriptivo exploratorio de carácter cualitativo a partir del diseño de un cuestionario abierto con el que se recoge información sobre la intervención que 34 profesionales vinculados a este campo diseñan y desarrollan. Bajo este planteamiento la investigación aquí recogida, pretende el cumplimiento de dos objetivos clave: identificar las confluencias y divergencias en la práctica profesional y establecer un protocolo de indicadores que nos ayude, posteriormente, a identificar buenas prácticas de intervención en ocio juvenil. | This article proposes to delimit good practices in the work with socially vulnerable young people from the characterization of the professional intervention, in the matter of leisure. For this purpose, an exploratory descriptive study of a qualitative nature is proposed, based on the design of an open questionnaire that collects information about the intervention that 34 professionals related to this field design and develop. Under this approach, the research gathered here aims to fulfill two key objectives: to identify the confluences and divergences in professional practice and to establish a protocol of indicators that will help us, later, to identify good intervention practices in youth leisure.

  3. Dos cupas complutenses

    Directory of Open Access Journals (Sweden)

    Stylow, Armin U.

    2006-12-01

    Full Text Available Publication of two cupae from the ancient territory of Complutum. One was found in excavations in Alcalá de Henares (Madrid and is unpublished; of the other one, which came to light in the church of Alovera (Guadalajara, a new reading is given.Se publican dos cupas del antiguo territorio de Complutum, una, inédita, encontrada en excavación en Alcalá de Henares (Madrid, y la segunda, procedente de la iglesia de Alovera (Guadalajara, con una nueva lectura.

  4. Impacte ambiental dos medicamentos

    OpenAIRE

    Pinto, Elsa Ariana

    2011-01-01

    Trabalho apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Ciências Farmacêuticas. O aumento do consumo de produtos farmacêuticos é uma realidade nas sociedades mundiais, e está intimamente relacionado com a crescente contaminação do meio ambiente por estes compostos e seus derivados. A presença destas substâncias nos diversos ecossistemas representa uma grande preocupação ambiental devido à possível interferência nos diversos sistemas ...

  5. The DosS-DosT/DosR Mycobacterial Sensor System

    Directory of Open Access Journals (Sweden)

    Santhosh Sivaramakrishnan

    2013-07-01

    Full Text Available DosS/DosR is a two-component regulatory system in which DosS, a heme-containing sensor also known as DevS, under certain conditions undergoes autophosphorylation and then transfers the phosphate to DosR, a DNA-binding protein that controls the entry of Mycobacterium tuberculosis and other mycobacteria into a latent, dormant state. DosT, a second sensor closely related to DosS, is present in M. tuberculosis and participates in the control of the dormancy response mediated by DosR. The binding of phosphorylated DosR to DNA initiates the expression of approximately fifty dormancy-linked genes. DosT is accepted to be a gas sensor that is activated in the ferrous state by the absence of an oxygen ligand or by the binding of NO or CO. DosS functions in a similar fashion as a gas sensor, but contradictory evidence has led to the suggestion that it also functions as a redox state sensor. This review focuses on the structure, biophysical properties, and function of the DosS/DosT heme sensors.

  6. Comportamiento del consumidor de productos agroecológicos frente a la aplicación de buenas prácticas agrícolas

    Directory of Open Access Journals (Sweden)

    Jorge Merino Toro

    2016-06-01

    Full Text Available La presente investigación evalúa el comportamiento del consumidor de productos agroecológicos comercializados por productores de PACAT (Corporación de Asociaciones de Productores Agroecológicos y Comercio Asociativo de Tungurahua frente a la aplicación de Buenas Prácticas Agrícolas (BPA, tomando como punto de partida el aumento descontrolado de ferias que comercializan productos bajo la denominación de agroecológicos en la provincia de Tungurahua. La principal herramienta utilizada en esta investigación fue la encuesta, aplicada a una muestra de 217 consumidores y 33 productores agroecológicos, con el uso de esta herramienta se determinó el comportamiento del consumidor de la Plaza Pachano y además se analizó la aplicación de Buenas Prácticas Agrícolas. Se reconoce la alta calidad como la principal razón para consumir productos agroecológicos, la frescura constituye la característica física que más atrae, y el producto más comprado fueron las hortalizas. Respecto a productores se determinó que aplican correctamente BPA. Palabras clave: Economía del consumidor, mercados agrarios y marketing, análisis de la oferta y de la demanda, producción, consumo.

  7. Mid-late Holocene environments of Agua Buena locality (34{sup 0}50'S; 69{sup 0}56'W), Mendoza, Argentina

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, Diego; Paez, M M [Laboratorio de Paleoecologia y Palinologia, Departamento de Biologia, Universidad Nacional de Mar del Plata, Funes 3350, (B7602AYL) Mar del Plata, Buenos Aires (Argentina); Mehl, A; Zarate, M A, E-mail: dnavarro@mdp.edu.a, E-mail: navarro.dd@gmail.co [INCITAP - Instituto de Ciencias de la Tierra y Ambientales de La Pampa. CONICET- Universidad Nacional de La Pampa, Uruguay 151, (L6300CLB) Santa Rosa, La Pampa (Argentina)

    2010-03-15

    In southern South America the acquisition of high-quality Holocene paleoclimate data is a priority due to the paucity of complete, continuous and well dated records. Here we report preliminary results from a combined sedimentological and palynological study of an alluvial fan sequence and the laterally connected sedimentary deposits of the Vega de la Cueva profile at Agua Buena east of the Andes in central Argentina. The main geomorphological units of the area were identified and mapped based on satellite image analysis and multiple field surveys. The sedimentological and pollen results allowed us to reconstruct the development of some environments. The Agua Buena record corresponds to the distal facies of the Arroyo Bayo alluvial fan starting the aggradation process prior to ca. 4100 cal yr BP. The organic-rich levels found were formed during the development of wetlands (vegas) dominated by Cyperaceae, Juncaceae and Poaceae. These highly productive environments with almost permanent water saturation were important between 4100 and 2800 cal yr BP, indicating more stable conditions. After 2800 cal yr BP, the organic content was comparatively lower with increasing sedimentation rates that are indicative of higher fluvial discharges. This information is fundamental to interpret both the pollen and charcoal records of the area and to evaluate their representativeness and potential to reconstruct past local and/or regional vegetation.

  8. Ni{sub 0,5}Zn{sub 0,5}Fe{sub 2}O{sub 3} ferrite synthesized by combustion and Pechini method for use in nanomedicine: methods evaluation; Ferrita Ni{sub 0,5}Zn{sub 0,5}Fe{sub 2}O{sub 3} sintetizada por reacao de combustao e metodo Pechini para uso na nanomedicina: avaliacao dos metodos

    Energy Technology Data Exchange (ETDEWEB)

    Albuquerque, I.L.T. de; Nascimento, A.L.C.; Costa, A.C.F.M., E-mail: allana.layla@gmail.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academica de Engenharia de Materiais

    2016-07-01

    The objective of this work was to synthesize the Ni0.5Zn0.5Fe2O3 ferrite by combustion reaction and Pechini method, and to evaluate structural characteristics and magnetic behavior for its use in nanomedicine. The synthesized ferrite was characterized by DRX, BET, TG and magnetic properties. According to the results of XRD, the Ni{sub 0,5}Zn{sub 0,5}Fe{sub 2}O{sub 3} ferrite synthesized by both methods presented nano crystallite sizes, high crystallinity, surface area, stable at high temperatures and with high saturation magnetization, being higher in the ferrite synthesized by combustion reaction. Both methods produced materials that could be used in nanomedicine.

  9. Dos estudios de casos

    Directory of Open Access Journals (Sweden)

    Hernán Guillermo Salazar Morales

    1989-04-01

    Full Text Available RESUMEN A continuación se presenta dos casos de estudio en donde se puede apreciar a la forma  como se establecen  las relaciones en una organización y lo que una DECISION  puede llegar a incidir en el desarrollo de las operaciones de una empresa. Decisiones basadas en la intuición, o en corazonadas, frecuentemente conducen en dirección equivocada, ocasionando pérdidas en tiempo, personal y dinero. El proceso de toma de decisiones deben ser TAREAS ESTRUCTURADAS que se sustenten con hechos. Su ejecución debe hacerse secuencialmente y cumplir con cada uno de sus pasos. El diseño de los  casos está orientado para que  sirvan como material de aplicación en la asignatura de  taller de planeación.

  10. Atividades medicinais dos isotiocianatos

    OpenAIRE

    Cabrita, Sara Filipa Coelho

    2014-01-01

    Dissertação para obtenção do grau de Mestre no Instituto Superior de Ciências da Saúde Egas Moniz A procura de novos agentes terapêuticos em compostos extraídos de plantas é cada vez mais investigada. De acordo com vários estudos epidemiológicos tem-se verificado que o consumo de plantas está associado a uma redução na incidência de cancro e vários compostos de origem vegetal tem demonstrado a capacidade de destruição de células cancerígenas in vitro e in vivo. Os isotiocianatos são uma...

  11. Hipertiroidismo congénito, Reporte de dos casos

    Directory of Open Access Journals (Sweden)

    Víctor Clemente Mendoza Rojas

    2014-04-01

    Full Text Available Introducción: El hipertiroidismo es una patología tiroidea poco frecuente en neonatos, relacionada con el antecedente materno de enfermedad de Graves, y por lo tanto con el paso transplacentario de inmunoglobulinas estimulantes del receptor de TSH. Presentación de casos: Reportamos dos casos de sexo femenino, que se presentaron en el Hospital Universitario de Santander. El primero de los casos se manifestó en la primera semana; el segundo caso se presentó tardíamente después del primer mes de vida. Los síntomas que presentaron en común fueron taquicardia persistente e hiperactividad. En uno de los casos la presentación clínica fue confundida con una infección bacteriana, debido a la presencia de fiebre. Se confirma el diagnóstico con los niveles de TSH muy suprimidos y T4 libre elevada, al menos al doble del límite superior. Los dos casos observaron medicamentos antitiroideos y propanolol con buena evolución clínica y de laboratorios; no se observamos complicaciones a corto o largo plazo como arritmias o craneosinostosis. Discusión: El hipertiroidismo congénito es una patología poco frecuente y siempre debe ser sospechado en recién nacidos de madres con antecedente de enfermedad de Graves, sus manifestaciones pueden presentarse prenatalmente o postnatalmente, y su diagnóstico y tratamiento deben ser oportunos para evitar secuelas a largo plazo o incluso la muerte

  12. Electronic Properties of LiFePO4 and Li doped LiFePO4

    Energy Technology Data Exchange (ETDEWEB)

    Zhuang, G.V.; Allen, J.L.; Ross, P.N.; Guo, J.-H.; Jow, T.R.

    2005-06-28

    The potential use of different iron phosphates as cathodematerials in lithium-ion batteries has recently been investigated.1 Oneof the promising candidates is LiFePO4. This compound has severaladvantages in comparison to the state-of-the-art cathode material incommercial rechargeable lithium batteries. Firstly, it has a hightheoretical capacity (170 mAh/g). Secondly, it occurs as mineraltriphylite in nature and is inexpensive, thermally stable, non-toxic andnon-hygroscopic. However, its low electronic conductivity (~;10-9 S/cm)results in low power capability. There has been intense worldwideresearch activity to find methods to increase the electronic conductivityof LiFePO4, including supervalent ion doping,2 introducingnon-carbonaceous network conduction3 and carbon coating, and theoptimization of the carbon coating on LiFePO4 particle surfaces.4Recently, the Li doped LiFePO4 (Li1+xFe1-xPO4) synthesized at ARL hasyield electronic conductivity increase up to 106.5 We studied electronicstructure of LiFePO4 and Li doped LiFePO4 by synchrotron based soft X-rayemission (XES) and X-ray absorption (XAS) spectroscopies. XAS probes theunoccupied partial density of states, while XES the occupied partialdensity of states. By combining XAS and XES measurements, we obtainedinformation on band gap and orbital character of both LiFePO4 and Lidoped LiFePO4. The occupied and unoccupied oxygen partial density ofstates (DOS) of LiFePO4 and 5 percent Li doped LiFePO4 are presented inFig. 1. Our experimental results clearly indicate that LiFePO4 has wideband gap (~; 4 eV). This value is much larger than what is predicted byDFT calculation. For 5 percent Li doped LiFePO4, a new doping state wascreated closer to the Fermi level, imparting p-type conductivity,consistent with thermopower measurement. Such observation substantiatesthe suggestion that high electronic conductivity in Li1.05Fe0.95 PO4 isdue to available number of charge carriers in the material. Furthermore,Hall effect

  13. Alimentación de dos especies de anfibios (Anura: Hylidae en la estación de bajas temperaturas y su relación con la acumulación de energía en Santa Fe, Argentina

    Directory of Open Access Journals (Sweden)

    Carolina Elizabet Antoniazzi

    2013-06-01

    Full Text Available Existe escasa información sobre la alimentación de las especies de anfibios activas durante la estación fría o las estrategias de utilización de reservas lipídicas como fuente de energía durante el periodo de bajas temperaturas. Por lo tanto, se analizaron las estrategias de obtención y acumulación energética durante la estación de bajas temperaturas en un anfibio que se reproduce principalmente en otoño-invierno, Hypsiboas pulchellus (Hp, y uno que lo hace en primavera-verano, Dendropsophus nanus (Dn. Para ello se analizó la alimentación de ambas especies y se utilizó el peso de los cuerpos grasos (CG como indicador del desarrollo de las reservas energéticas. Si bien se encontró una elevada similitud en la dieta entre las especies, esto no implicó la ausencia de diferencias en las estrategias de obtención energética entre ellas. El bajo índice de vacuidad gastrointestinal de Hp, acompañado de CG poco desarrollados, permite señalar que, para sostener la elevada demanda energética de la actividad reproductiva concentrada en el otoño-invierno, esta especie continúa alimentándose aún en temperaturas bajas. Por otro lado, el índice de vacuidad de Dn fue mayor al de Hp, mientras que sus CG se encontraron bien desarrollados, por lo que esta especie utilizaría en mayor medida sus reservas lipídicas como fuente de energía para transitar el período de bajas temperaturas y llegar en buenas condiciones a la temporada reproductiva en la próxima primavera-verano.

  14. Buenas prácticas de manufactura en Bancos de Leche Humana de la Red Nacional de Bancos de Leche Humana de Guatemala

    Directory of Open Access Journals (Sweden)

    Evany Guzmán

    2017-03-01

    Full Text Available La presente investigación tuvo como objetivo verificar el cumplimiento de las Buenas Prácticas de Manufactura (BPM en siete Bancos de Leche Humana (BLH de la Red Nacional, estableciendo las condiciones y recomendaciones de infraestructura, equipos, procesos, procedimientos y personal para el mejoramiento de los BLH con el fin de asegurar su adecuado funcionamiento. Se realizó una auditoría diagnóstica evaluando las condiciones de BPM en los BLH de la Red Nacional utilizando la ficha de inspección de BPM del Reglamento Técnico Centroamericano (RTCA 67.01.33:06. La información recolectada se analizó mediante estadística descriptiva calculando un valor sobre 100 puntos, con el fin de valorar las condiciones y realizar un informe donde se detallaron las deficiencias y recomendaciones para mejorar el sistema y garantizar leche humana inocua, que fue entregado a cada BLH evaluado. Los BLH del Hospital General San Juan de Dios (HGSJD y del Hospital Regional de Antigua Guatemala obtuvieron punteos que indica que poseen buenas condiciones y son aptas para procesar la leche humana; los BLH del Hospital Regional de Cobán y Puerto Barrios con regulares condiciones con correcciones para el proceso con riesgo de contaminación; los BLH de Santa Rosa y Totonicapán con condiciones ineficientes que urge corregir y el BLH de Zacapa obtuvo punteo que indica condiciones inaceptables que sugieren considerar el cierre. La mayoría de BLH posee deficiencias claras, sin embargo, son aptos para procesar la leche humana con resultados inocuos con excepción del BLH de Zacapa.

  15. Synthesis and characterization particles of Ba{sub 0,50}Sr{sub 0,50}Co{sub 0,80}Fe{sub 0,20}O{sub 3} obtained by the citrate-EDTA technique; Sintese e caracterizacao de particulados de Ba{sub 0,50}Sr{sub 0,50}Co{sub 0,80}Fe{sub 0,20}O{sub 3} obtidos pela tecnica dos citratos-EDTA

    Energy Technology Data Exchange (ETDEWEB)

    Bonturim, E.; Vargas, R.A.; Andreoli, M.; Seo, E.S.M., E-mail: ebonturim@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (CCTM/IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencia e Tecnologia de Materiais

    2010-07-01

    The Ba{sub (1-x)}Sr{sub (x)}Co{sub (1-y)}Fe{sub (y)}O{sub (3)} (BSCF) has been studied as a cathode material for Intermediate Temperature Solid Oxide Fuel Cell, due to its better ion and electron conduction. This work aims to study the synthesis of the compound obtained from the citrate-EDTA technique. Thermogravimetric analysis indicated the formation of the compound above 800 deg C. The materials calcined at temperatures of 700, 800 and 900 deg C for 5 h showed cubic pseudo-perovskite structure, according to the literature. By analysis of X-ray fluorescence were obtained powders with nominal chemical composition in the temperature range studied. The micrographs obtained by SEM and particle size distribution analysis showed the formation of particle with diameters below 1 micron. (author)

  16. Regenerated Fe is tasty!

    Science.gov (United States)

    Nuester, J.; Twining, B. S.

    2012-12-01

    Bioavailability of nutrients is an essential factor controlling primary productivity in the ocean. In addition to macronutrients such as nitrogen and phosphorous, availability of the trace element iron unequivocally affects growth rates and community structure of phytoplankton and thereby primary productivity in many ocean regions. External sources of iron such as Aeolian dust, upwelling of Fe-rich waters, and hydrothermal are reduced in high-nutrient low-chlorophyll regions, and most Fe used by phytoplankton has been regenerated by zooplankton. While zooplankton regeneration of Fe was first shown two decades ago, major factors controlling this process such as chemical composition of prey and grazer taxonomy are not well constrained. As pH varies significantly in digestive systems between protozoa and mesozooplankton, we hypothesize that the extent and the bioavailability of regenerated Fe is a function of the digestive physiology. Furthermore, major element components such as silica for diatoms and calcium carbonate for cocolithophores may be able to buffer the pH of digestive systems of different grazer taxa. Such effects may further influence the magnitude and bioavailability of regenerated Fe. In order to constrain the effect of grazer taxonomy and chemical composition of prey on Fe bioavailability, 55Fe-labeled phytoplankton were fed to different grazers and unlabeled phytoplankton were subsequently inoculated to the filtrate of the grazing experiment in the regrowth phase of the experiment, and the uptake of 55Fe into the phytoplankton biomass was monitored over time. A parallel uptake experiment using inorganic 55Fe was used to compare the bioavailability of regenerated and inorganic Fe to the same phytoplankton species. Furthermore, some samples of the inorganic and the regenerated uptake experiments were treated with an oxalate rinse to remove any adsorbed Fe. This allowed us to estimate the adsorption of 55Fe from either source to the cell walls of

  17. Dos chalets, en Suecia

    Directory of Open Access Journals (Sweden)

    Erskine, Ralph

    1968-04-01

    Full Text Available Villa Engström, at Sorunda This house, of semi-spheric shape, has besically only one floor level, without basement. However, the guest room and the attic are a kind of second floor within the cupula. This is an experiment, with a view to the possible mass construction of this prototype. The various rooms are grouped in two blocks, one comprising the bedrooms, which are cellular type and of minimum size, and the bathrooms; the other includes the children's room, a living room which extends into the vestibule, and guest room at a higher level. Villa Ström, near Stockholm This house is practically cube shaped, with ample terraces, which are structurally independent of the central volume. A principal aim has been to obtain fine views in all directions, and also to take advantage of the ground slope. This house, of original and competent design, includes indoor gardens which add colour and life to the rooms.Villa Engström, en Sorunda Esta vivienda, que presenta una «forma» semiesferica, es fundamentalmente un edificio de una sola planta, sin sótano; sin embargo, el cuarto de huéspedes y el «ático» forman como una especie de doble planta dentro de la cúpula. Se trata de una experiencia con vistas a una posible fabricación en serie. Las diferentes habitaciones se hallan agrupadas en dos bloques: uno de ellos ocupado por los dormitorios —que son de tipo celular y de tamaño mínimo—, y los cuartos de baño; y el otro que comprende un cuarto para los niños, la sala de estar —unida con el vestíbulo—, y la habitación de los huéspedes en la parte superior. Villa Ström, cerca de Estocolmo La casa es prácticamente un cubo, con terrazas amplias e independientes estructuralmente del volumen principal. En todo caso, ha dominado la doble preocupación de conseguir magníficas vistas hacia todos los alrededores y una adaptación total a la pendiente del terreno. La vivienda se ha resuelto con maestría y originalidad, procurando zonas

  18. Desarrollo de Herramientas Enfocadas en Ayudar a las Pymes de Desarrollo de Software en la Implementación de Buenas Prácticas de Gestión de Proyectos

    Directory of Open Access Journals (Sweden)

    Yolanda-Meredith García

    2017-05-01

    Full Text Available La Industria del desarrollo de software constituye un factor clave en la economía. En Latinoamérica este sector se compone por el 99% de pymes. Esto resalta la importancia de la implementación de buenas prácticas de ingeniería de software en las pymes para asegurar su mejora continua. En este contexto, existen diversos modelos y estándares que contienen buenas prácticas enfocadas en mejorar los procesos de desarrollo de software tales como CMMI, ISO-12207, ISO-15504, etc. Sin embargo, para aplicar dichos modelos, las pymes requieren adaptarlos según su tamaño y tipo de negocio. Por lo tanto, se apoyan de técnicas y herramientas para la implementación de buenas prácticas contenidas en ellos. El objetivo de este artículo es presentar una herramienta que facilita la implementación de buenas prácticas para realizar una la gestión de riesgos básica en una pyme.

  19. Artritis séptica del pubis en dos deportistas

    Directory of Open Access Journals (Sweden)

    José A. Andrews

    2012-06-01

    Full Text Available La artritis séptica de pubis u osteomielitis púbica es la infección que compromete la sínfisis pubiana y su articulación. Es poco frecuente, representando menos del 1% de las osteomielitis. Afecta más a menudo a atletas jóvenes y a mujeres que se someten a cirugía ginecológica o urológica. Se presenta con fiebre y dolor púbico, irradiado a genitales, que aumenta con la movilización de la cadera lo que produce claudicación de la marcha. Debe hacerse el diagnóstico diferencial con la osteítis del pubis que es una condición inflamatoria estéril. La punción guiada por imagen suele ser necesaria para el diagnóstico diferencial con la osteítis del pubis. El diagnóstico se basa en la clínica apoyada en el aislamiento microbiológico, métodos por imágenes e incremento de las proteínas de fase aguda. Los agentes etiológicos más comúnmente encontrados son Staphylococcus aureus, seguidos de bacilos gram negativos, o pueden ser polimicrobianos en posquirúrgicos. El tratamiento antibiótico se ajusta al germen aislado por cultivo, además de antiinflamatorios y reposo. El desbridamiento quirúrgico se requiere hasta en el 55% de los casos. Se recomiendan antibióticos por 6 semanas. Se presentan dos casos de osteomielitis del pubis por S. aureus, con buena respuesta al tratamiento. Ambos pacientes eran jóvenes y deportistas.

  20. EL VALOR AÑADIDO DE LAS BUENAS PRÁCTICAS CON TIC EN LOS CENTROS EDUCATIVOS VALUE-ADDED OF GOOD PRACTICES WITH ICT IN SCHOOLS

    Directory of Open Access Journals (Sweden)

    Teresa González Ramírez

    2010-02-01

    Full Text Available Este artículo aporta un marco teórico-metodológico en el que situar el impacto o valor añadido de las Buenas Prácticas con TIC en los centros educativos. Para ello, parte de una descripción de las políticas de integración de las Tecnologías de la Comunicación y la Información (TIC en nuestro país y más específicamente en la comunidad autónoma andaluza. Con posterioridad se presentan los principales enfoques metodológicos que orientan actualmente la evaluación de políticas educativas y por extensión las políticas de integración TIC. El análisis de las políticas se concreta en el concepto de Buenas Prácticas como una manera de evaluar las políticas de integración de las TIC en los centros enmarcado en el enfoque de efectividad de las escuelas y más específicamente dentro de los modelos de valor añadido en educación. Finalmente señalamos la orientación metodológica que adquiere en nuestro trabajo el concepto de valor añadido, aportando una relación de indicadores que pueden servir para la evaluación de las políticas TIC asentada en la evaluación de centros y en el desarrollo de prácticas docentes. This article provides a theoretical and methodological framework in which to place the impact or Value Added of the Best Practices with ICT in schools. To do so, starting from a description of policies of integration of IT and Communication Technologies (ICTs in our country, and more specifically in the autonomous Andalusian community. Following are the main methodological approaches that guide the assessment of current education policies and, by extension, the integration of ICT policies. Policy analysis reflected in the concept of Good Practices as a way to evaluate the policies of integration of ICT in schools within the scope of effectiveness of schools and more specifically within the value-added models in education. Finally, we note that the methodological guidance in our work takes on the concept of added

  1. Fe atom exchange between aqueous Fe2+ and magnetite.

    Science.gov (United States)

    Gorski, Christopher A; Handler, Robert M; Beard, Brian L; Pasakarnis, Timothy; Johnson, Clark M; Scherer, Michelle M

    2012-11-20

    The reaction between magnetite and aqueous Fe(2+) has been extensively studied due to its role in contaminant reduction, trace-metal sequestration, and microbial respiration. Previous work has demonstrated that the reaction of Fe(2+) with magnetite (Fe(3)O(4)) results in the structural incorporation of Fe(2+) and an increase in the bulk Fe(2+) content of magnetite. It is unclear, however, whether significant Fe atom exchange occurs between magnetite and aqueous Fe(2+), as has been observed for other Fe oxides. Here, we measured the extent of Fe atom exchange between aqueous Fe(2+) and magnetite by reacting isotopically "normal" magnetite with (57)Fe-enriched aqueous Fe(2+). The extent of Fe atom exchange between magnetite and aqueous Fe(2+) was significant (54-71%), and went well beyond the amount of Fe atoms found at the near surface. Mössbauer spectroscopy of magnetite reacted with (56)Fe(2+) indicate that no preferential exchange of octahedral or tetrahedral sites occurred. Exchange experiments conducted with Co-ferrite (Co(2+)Fe(2)(3+)O(4)) showed little impact of Co substitution on the rate or extent of atom exchange. Bulk electron conduction, as previously invoked to explain Fe atom exchange in goethite, is a possible mechanism, but if it is occurring, conduction does not appear to be the rate-limiting step. The lack of significant impact of Co substitution on the kinetics of Fe atom exchange, and the relatively high diffusion coefficients reported for magnetite suggest that for magnetite, unlike goethite, Fe atom diffusion is a plausible mechanism to explain the rapid rates of Fe atom exchange in magnetite.

  2. Physical Properties of Intermetallic FE2VA1

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Ye [Iowa State Univ., Ames, IA (United States)

    2001-01-01

    Fe2VAl has recently been discovered to have a negative temperature coefficient of resistivity, moderately enhanced specific heat coefficient, and a large DOS at the Fermi level by photoemission. This triggered a round of heated research to understand the ground state of this material, both theoretically and experimentally. here they report a comprehensive characterization of Fe2VAl. X-ray diffraction exhibited appreciable antisite disorder in all of our samples. FTIR spectroscopy measurements showed that the carrier density and scattering time had little sample-to-sample variation or temperature dependence for near-stoichiometric samples. FTIR and DC resistivity suggest that the transport properties of Fe2VAl are influenced by both localized and delocalized carriers, with the former primarily responsible for the negative temperature coefficient of resistivity. Magnetization measurements reveal that near-stoichiometric samples have superparamagnetic clusters with at least two sizes of moments. X-ray photoemission from Fe core level showed localized magnetic moments on site-exchanged Fe. They conclude that in Fe2VAl, antisite disorder causes significant modification to the semi-metallic band structure proposed by LDA calculations. With antisite disorder considered, they are now able to explain most of the physical properties of Fe2VAl.

  3. Avaliação e monitoramento dos mecanismos de deterioração do concreto exposto ao íons cloreto e sulfato e o efeito da adição de Nano-Fe3O4 por espectroscopia de impedância eletroquímica

    OpenAIRE

    Bragança, Mariana D' Orey Gaivão Portella

    2014-01-01

    Orientadora: Profª. Drª. Cláudia Eliana Bruno Marino Tese (doutorado) - Universidade Federal do Paraná, Setor de Tecnologia, Programa de Pós-Graduação em Engenharia e Ciência dos Materiais - PIPE. Defesa: Curitiba, 05/12/2014 Inclui bibliografia Área de concentração: Engenharia e ciencia de materiais Resumo: Determinados agentes iônicos presentes nos mais diversos ambientes (solo, água e ar) aos quais as obras de engenharia estão expostas como, por exemplo, os íons cloreto e sulfa...

  4. How good classroom organisation can benefit teaching (Cómo una buena organización de aula puede beneficiar a la hora de dar clase)

    OpenAIRE

    Marro Guantes, Noemi

    2016-01-01

    El presente documento contiene las bases de diversos autores conocidos, así como mi experiencia personal en dos colegios diferentes y en dos países diferentes, lo cual me ha dado la oportunidad de comparar y hablar sobre dos organizaciones de aula distintas. Este trabajo escrito intenta crear una nueva organización de aula utilizando los recursos y espacios que nuestro sistema educativo nos permite. Como educadores, debemos ser conscientes de que con los recursos y espacios que nos dan pod...

  5. NGC 2287: Un cúmulo abierto rico en binarias espectroscópicas de dos espectros

    Science.gov (United States)

    Levato, H.; Malaroda, S.; García, B.; Grosso, M.

    NGC 2287 contiene 100 estrellas con buena fotometría y 40 con tipos MK. En 1979 Levato et al., usando la técnica de la clasificación espectral, descubrieron que la mayoría de las estrellas en el rango B8-A0 eran binarias espectroscópicas con una inusual proporción de binarias con dos espectros. El presente proyecto tuvo el propósito de confirmar la naturaleza binaria de los miembros del cúmulo. Hemos obtenido espectros con resolución 14000 de 15 estrellas clasificadas como binarias. Los espectros, que abarcan la región λ 3500-λ 6000 Å, permitieron confirmar la naturaleza binaria de varias de las estrellas en la muestra. Hacemos notar el considerable interés astrofísico de este cúmulo abierto.

  6. La importancia de una buena estrategia de fijación de precios como herramienta de penetración de mercados

    Directory of Open Access Journals (Sweden)

    Carlos Manuel Córdoba Segovia

    2017-11-01

    Full Text Available Una empresa para estar a la vanguardia y al nivel de sus rivales, con bienes y servicios de alto valor agregado y notable especialización, requiere de una buena estrategia de fijación de precios (pricing que sea atractiva para el cliente y, a la vez, rentable para la compañía. Este objetivo se puede alcanzar mediante técnicas de optimización financiera, centradas en el conocimiento al detalle de la estructura de costos de la empresa, que permitan aumentar la participación en el mercado a través de precios competitivos. En este artículo se presentan diferentes estrategias de costos y de fijación de precios que, de acuerdo con la naturaleza de la empresa, se pueden utilizar para competir en el mercado de manera eficiente. Aunque, en la práctica, no existe una fórmula ideal de fijación de precios, la estrategia acertada será aquella que se adapte de la mejor manera al objetivo que quiera alcanzar la empresa en un momento determinado. El propósito de este ensayo es exponer al lector las estrategias de pricing comúnmente utilizadas en el mercado, con el fin de demostrar su incidencia en los resultados financieros de las empresas y sugerir alternativas de toma de decisiones gerenciales.

  7. GOOD PRACTICES FOR VIRTUAL CLASSROOM IN UNIVERSITARY BLENDED LEARNING BUENAS PRÁCTICAS DE AULAS VIRTUALES EN LA DOCENCIA UNIVERSITARIA SEMIPRESENCIAL

    Directory of Open Access Journals (Sweden)

    Manuel Area Moreira

    2010-02-01

    Full Text Available We present the design and results of a study conducted at the University of La Laguna (ULL to identify best practices in virtual classrooms in Higher Education developed in the form of blended learning. The study was conducted in the first quarter of 2008 and analyzed a large sample of virtual classrooms (N = 107 in the Virtual Campus of the University during the period 2005-07. This article presents six examples of virtual classrooms by scientific fields characterized by the incorporation of information resources, communication and experiential learning. En este artículo presentamos el diseño y resultados de un estudio realizado en la Universidad de La Laguna (ULL destinado a identificar buenas prácticas de aulas virtuales en la docencia universitaria desarrolladas bajo la modalidad de blended learning o enseñanza semipresencial. El estudio se desarrolló en el primer trimestre del año 2008 y analizó una importante muestra de las aulas virtuales (N= 107 existentes en el Campus Virtual de dicha universidad en el periodo 2005-07. Se seleccionaron seis ejemplos de aulas virtuales, clasificados por campos científicos, caracterizadas por la incorporación de recursos de información, de comunicación y de aprendizaje experiencial.

  8. Buenas prácticas en el desarrollo de trabajo colaborativo en materias TIC aplicadas a la educación

    Directory of Open Access Journals (Sweden)

    Prudencia Gutiérrez Esteban

    2011-01-01

    del alumnado como metodología, la innovación docente como filosofía, el uso de las TIC aplicadas a la Enseñanza y el Aprendizaje y el empleo de estas herramientas para el desarrollo de la competencia digital en el alumnado universitario. Tras las experiencias desarrolladas, se realiza un análisis de las mismas en torno a la organización y gestión de espacios virtuales, los indicadores del proceso E-A y las infraestructuras TIC, a partir de las valoraciones realizadas por alumnado y profesorado sobre las dificultades y fortalezas encontradas en el desarrollo de las actividades y el uso de estas herramientas. Lo más destacable de este trabajo, no es sólo la opinión de las y los participantes sobre las experiencias, sino las propuestas realizadas por la osibilidad que nos ofrecen las herramientas colaborativas para el desarrollo de buenas prácticas usando las TIC en la educación superior, con la finalidad de mejorarla.

  9. La importancia de tener buena salud en la autovaloración de la calidad de vida. El ejemplo de los alumnos mayores de las Islas Baleares

    Directory of Open Access Journals (Sweden)

    Liberto Macías González

    2014-08-01

    Full Text Available El presente trabajo se enmarca dentro de un estudio más amplio sobre la calidad de vida de personas mayores que están participando en un programa universitario para mayores. La parte que presentamos pertenece a una primera fase, centrada en la valoración de la calidad de vida de personas que se han matriculado en el primer curso del Diploma Sènior(que consta de tres cursos en total de la Universitat Oberta per a Majors (UOM, programa educativo ofertado por la Universitat de les Illes Balears (UIB a personas mayores de 50 años. En este trabajo se reflejan los resultados de la percepción subjetiva de la calidad de vida de las personas mayores matriculadas en el primer curso, en tres años académicos distintos y correlativos (2009-10, 2010-11 y 2011-12 del mencionado programa universitario para mayores, con el objetivo de conocer y valorar cual es el componente, relacionado con la calidad de vida, al que le dan más importancia o consideran prioritario para su calidad de vida. Los resultados muestran que una amplia mayoría, el 93%, considera que el componente más importante en su calidad de vida es “tener buena salud”, así como sólo un 0,8% del total de la muestra participante percibe su calidad de vida como baja

  10. Evaluación de calidad de fuentes y recursos digitales: Guía de buenas prácticas

    Directory of Open Access Journals (Sweden)

    Mª Dolores Ayuso García

    2006-01-01

    Full Text Available A partir de la propuesta de un Protocolo de actuación para la evaluación de fuentes de información digitales publicadas en Internet las autoras presentan en este trabajo una Guía de Buenas Prácticas. Esta Guía esta orientada hacia los profe-sionales de la información y documentación científica y técnica, como instrumento formativo a partir del cual puede hacerse más fácil la comprensión y el análisis de los recursos publicados en Internet a los profesionales de los servicios de referencia. Un compendio de casos prácticos identifica los parámetros que ayudan a la evaluación crítica de la calidad de los recursos digitales, proporcionando ideas para estruc-turar proyectos de desarrollo de publicaciones digitales

  11. La salud y la vida buena: aportes del enfoque de las capacidades de Amartya Sen para el razonamiento ético en salud pública

    Directory of Open Access Journals (Sweden)

    Diego Alveiro Restrepo-Ochoa

    2013-12-01

    Full Text Available El objetivo del presente trabajo es analizar el aporte del enfoque de las capacidades de Amartya Sen para el razonamiento ético en salud pública. A partir de las críticas del enfoque de las capacidades al utilitarismo, se propone una concepción de salud sustentada en cuatro características: una noción de vida buena de carácter pluralista, la expansión de la libertad como fundamento ético de las acciones en salud, la concepción de la persona como agente y el reconocimiento de la visión interna de la salud, basada en una objetividad posicional. El aporte del enfoque de las capacidades para el razonamiento ético en salud pública puede resumirse en el reconocimiento de cuatro aspectos: la insuficiencia de la asistencia sanitaria como criterio de la ventaja individual, la equidad en salud como un aspecto fundamental de la justicia social, la relevancia de la visión que tienen las personas con relación a su propia salud y el desarrollo de las capacidades como finalidad de las políticas públicas en el campo de la salud pública.

  12. Anatomia interna dos caninos inferiores

    OpenAIRE

    Oliveira, Simone H.G; Iorio, Lecy S.

    2010-01-01

    A falta de conhecimento da anatomia da cavidade pulpar é uma das principais razões do insucesso da terapia endodôntica dos caninos inferiores. Foram utilizados 1040 caninos inferiores cuja incidência de bifurcações foi avaliada através de estudo radiográfico e comparada com o método de injeção e diafanização dos mesmos dentes. Também foram estudadas outras características internas visualizad...

  13. Desvios Axiais dos Membros Inferiores

    OpenAIRE

    Cassiano Neves, M; Campagnolo, J

    2009-01-01

    As deformidades axiais dos membros inferiores constituem um dos principais motivos de consulta na área de Ortopedia Infantil. Esta situação deve-se, por um lado, ao facto de haver uma grande percentagem de crianças (cerca de 20%) que apresentam uma deformidade fisiológica durante o desenvolvimento e, por outro, à «tradição» existente, segundo a qual estes desvios necessitam de um tratamento, usualmente por calçado ortopédico. Torna-se, por isso, imperioso destrinçar o fisiológico do ...

  14. Interlayer Thickness Effects on Magnetic Properties of X/FePtAg (X=FePt/Fe and Fe/FePt Trilayers

    Directory of Open Access Journals (Sweden)

    Jai-Lin Tsai

    2012-01-01

    Full Text Available A soft/hard FePt/Fe/FePtAg and Fe/FePt/FePtAg trilayers with perpendicular magnetization were prepared on a glass substrate. Inserting disordered FePt layer allowed modification of magnetic anisotropy of the Fe/FePtAg sharp interface to Fe/FePt/FePtAg stepwise interface. The out-of-plane coercivity field was modulated as a function of the FePt thickness because of the interface coupling attenuation between Fe and FePtAg. The coercivity was inversely proportional to the FePt thickness as evidenced by the pinning effect at the stepwise interface. Additionally, the out-of-plane magnetization was controlled by domain wall pinning effect. The in-plane magnetization reversal processes occurred in two steps like in exchange spring systems and attributed to the domain wall nucleation and its propagation from Fe/FePt layer into FePtAg layer.

  15. Caso de buenas prácticas en la formación en TICs y fomento de la competencia digital en la sociedad, y, especialmente, en los colectivos en riesgo de exclusión digital

    Directory of Open Access Journals (Sweden)

    Nuria Hernández León

    2017-07-01

    Full Text Available En este artículo se realiza un análisis de un caso de buenas prácticas destinado a la formación en TICS para fomentar la adquisión de competencia digital en la sociedad, haciendo especial énfasis en los colectivos que se encuentran en riesgo de exclusión digital, realizado a través de un proyecto regional en Castilla y Léon (España, dependiente de la Administración Pública. Se toma como ejemplo el caso de un centro en la localidad de Salamanca (España debido a la profesionalidad de los trabajadores, sus buenas prácticas, sus resultados y por ser el modelo a seguir del proyecto, tomando como datos de análisis el primer año de apertura del centro

  16. Guía de buenas prácticas de producción en la Acuicultura Orgánica para unidades productivas de pequeña y mediana escala

    OpenAIRE

    Colusso, Graciela

    2015-01-01

    La producción orgánica es un sistema holístico de gestión sostenible de la producción. Dicho sistema, emplea “Buenas Prácticas” de gestión, mediante métodos culturales, biológicos y mecánicos que fomentan y mejoran la salud del agrosistema, la biodiversidad, los ciclos biológicos y la actividad biológica del suelo (Codex). En lo que se refiere a las Buenas Prácticas que implican la producción orgánica en la acuicultura, aparecen como una elección fundamental ya que tiene en cuenta ...

  17. Buenas prácticas para el diseño e implementación de sistemas nacionales de monitoreo para la adaptación al cambio climático

    DEFF Research Database (Denmark)

    Naswa, Prakriti; Trærup, Sara Lærke Meltofte; Bouroncle, Claudia

    En este informe identificaremos, analizaremos y compararemos buenas prácticas internacionales dediseño e implementación de indicadores para sistemas de monitoreo y evaluación para la adaptación alcambio climático. El primer capítulo ofrece una introducción al contexto y la terminología clave en el...

  18. Enhancement of L21 order and spin-polarization in Co2FeSi thin film by substitution of Fe with Ti

    Science.gov (United States)

    Chen, Jiamin; Sakuraba, Y.; Masuda, K.; Miura, Y.; Li, S.; Kasai, S.; Furubayashi, T.; Hono, K.

    2017-06-01

    We investigated the effect of Ti substitution for Fe in Co2FeSi Heusler alloy (Co2Fe1-xTixSi) on their electronic structure, chemical ordering, and spin-dependent transport properties. First-principles calculations of the density of states (DOS) indicated that the peak just above the Fermi level in the minority-spin DOS (the conduction band edge of half-metallic gap) shifts towards higher energies with increasing Ti, leading to the enhancement in the half-metallic gap and the spin-polarization. We found in epitaxial Co2(Fe1-xTix)Si thin films that the required annealing temperature for long range L21-ordering can be substantially reduced from 650 °C for Co2FeSi to 400 °C for x ≥ 0.2. The enhancement of spin-polarization by the substitution of Fe with Ti was experimentally confirmed from anisotropic magnetoresistance measurements and spin-accumulation signals in non-local spin valve devices with the Co2Fe1-xTixSi films.

  19. Implementación de buenas prácticas de promoción de personal y su relación con la cultura y el compromiso con la organización

    Directory of Open Access Journals (Sweden)

    Merlin Patricia Grueso Hinestroza

    2010-04-01

    Full Text Available La investigación genera hipótesis y prueba un modelo de relaciones entre los valores de la cultura organizacional, la implementación de una buena práctica de promoción de personal desde la perspectiva de género y el compromiso con la organización. Para la prueba de hipótesis se emplea un modelo de ecuaciones estructurales y se realiza una encuesta a 425 empleados. Los resultados llevan a concluir que los valores distancia al poder y orientación de largo plazo predicen la implementación de buenas prácticas de promoción de personal; los componentes del compromiso con la organización no evidenciaron asociaciones significativas con la implementación de una buena práctica de promoción de personal. El estudio contribuye al desarrollo de un cuerpo de investigación en torno a las implicaciones de la perspectiva de género en las organizaciones.

  20. Sobrepeso como factor de riesgo en la población de escolares de la comunidad de Díaz (Santa Fe

    Directory of Open Access Journals (Sweden)

    Tunkiewiecz, Iván R.

    2005-01-01

    Full Text Available Díaz, comuna perteneciente al Dpto San Jerónimo, S.Fe. Población: 1782 habit., 52% varones, 48% mujeres, siendo el 92% población urbana con buenas condiciones sanitarias y de vivienda. En el área urbana existen dos escuelas: 1 educación primaria con oferta educativa Inicial y EGB común. Mat.: 252 alumnos y 2 educación secundaria: 99 alumnos. Estudios previos sobre valores de presión arterial y variables antropométricas realizados en dicha comunidad mostraron valores elevados de IMC (27 en mujeres en el intervalo etario 30-40, por lo cual se decidió determinar el estado nutricional de la población escolar. Variables antropométricas: talla (cm (T, peso (kg (P, perímetro braquial (cm (PB, pliegues subescapular y tricipital (mm (PS, PTr en 228 individuos (5-18 años. Índices: TE, PE y PT con transformación z e IMC. Estratificación/sexo-edad: Varones (V1 == 11/ = 10/<= 11.99.Variables: T, P, PB, PS y PTr (N, x±DE. V1: 54, 127±10,66, 28±7, 20±2, 8±5, 14±5; V2: 33, 151±10, 44±10, 23±3, 10±7, 17±6; M1: 59, 122±10, 25±6, 19±2, 9±5, 14±5; M2: 26, 141±7, 37±9, 22±3, 12±7, 19±7. Índices: TEz, PEz, PTz[V1,M1] y TEz, PEz e IMC[x±DE;V2,M2]. V1: -0.33, 0.15, 0.57; V2: -0.30, -4.18E-02, 19±3; M1: -0.40, 0.12, 0.69; M2: -0.59, -0.14, 19±3. Se concluye: 1- no existe desnutrición 2- se observa una tendencia al sobrepeso.

  1. Buenas prácticas para la selección de recursos educativos abiertos: experiencias del MOOC innovación educativa con REA

    Directory of Open Access Journals (Sweden)

    Acuña Sossa, Mildred

    2016-05-01

    Full Text Available El artículo expone la indagación acerca de los Recursos Educativos Abiertos (REA con la colaboración interuniversitaria entre el Instituto Tecnológico de Estudios Superiores de Monterrey, México, y la Universidad Estatal a Distancia de Costa Rica. Esta temática ha sido poco estudiada y ambas universidades se vieron en la necesidad de conocer cómo se realiza la selección de estos recursos. Asimismo, expresa las buenas prácticas de selección de REA utilizadas por los participantes en el curso Innovación Educativa con Recursos Abiertos que se facilitó mediante el formato Massive Open Online Course (MOOC por sus siglas en inglés y así, formular recomendaciones que orienten su elección. Con una investigación exploratoria de tipo cualitativo se realizó una revisión de instrumentos de autoevaluación completados por los participantes, se generaron categorías para describir los aportes publicados en los foros del curso y las tareas que completaron los participantes con respecto al tema de REA. Se concluyó que lo habitual es hacer una valoración directa del recurso antes de usarlo o consultar con colegas o expertos en la materia para hacer una selección adecuada y útil para la práctica educativa. También se destacó que la búsqueda de estos recursos se realiza con la ayuda del navegador web Google, en las revistas digitales y las bases de datos institucionales. Además, se resalta la necesidad de un mejor manejo de los REA por parte de los participantes del curso, y de generar más habilidades para su búsqueda y selección.

  2. BUENAS PRÁCTICAS PARA LA SELECCIÓN DE RECURSOS EDUCATIVOS ABIERTOS: EXPERIENCIAS DEL MOOC INNOVACIÓN EDUCATIVA CON REA

    Directory of Open Access Journals (Sweden)

    Mildred Acuña Sossa

    2016-01-01

    Full Text Available El artículo expone la indagación acerca de los Recursos Educativos Abiertos (REA con la colaboración interuniversitaria entre el Instituto Tecnológico de Estudios Superiores de Monterrey, México, y la Universidad Estatal a Distancia de Costa Rica. Esta temática ha sido poco estudiada y ambas universidades se vieron en la necesidad de conocer cómo se realiza la selección de estos recursos. Asimismo, expresa las buenas prácticas de selección de REA utilizadas por los participantes en el curso Innovación Educativa con Recursos Abiertos que se facilitó mediante el formato Massive Open Online Course (MOOC por sus siglas en inglés y así, formular recomendaciones que orienten su elección. Con una investigación exploratoria de tipo cualitativo se realizó una revisión de instrumentos de autoevaluación completados por los participantes, se generaron categorías para describir los aportes publicados en los foros del curso y las tareas que completaron los participantes con respecto al tema de REA. Se concluyó que lo habitual es hacer una valoración directa del recurso antes de usarlo o consultar con colegas o expertos en la materia para hacer una selección adecuada y útil para la práctica educativa. También se destacó que la búsqueda de estos recursos se realiza con la ayuda del navegador web Google, en las revistas digitales y las bases de datos institucionales. Además, se resalta la necesidad de un mejor manejo de los REA por parte de los participantes del curso, y de generar más habilidades para su búsqueda y selección.

  3. Physical Properties of Intermetallic FE sub 2 VA1

    CERN Document Server

    Ye Fen

    2002-01-01

    Fe sub 2 VAl has recently been discovered to have a negative temperature coefficient of resistivity, moderately enhanced specific heat coefficient, and a large DOS at the Fermi level by photoemission. This triggered a round of heated research to understand the ground state of this material, both theoretically and experimentally. here they report a comprehensive characterization of Fe sub 2 VAl. X-ray diffraction exhibited appreciable antisite disorder in all of our samples. FTIR spectroscopy measurements showed that the carrier density and scattering time had little sample-to-sample variation or temperature dependence for near-stoichiometric samples. FTIR and DC resistivity suggest that the transport properties of Fe sub 2 VAl are influenced by both localized and delocalized carriers, with the former primarily responsible for the negative temperature coefficient of resistivity. Magnetization measurements reveal that near-stoichiometric samples have superparamagnetic clusters with at least two sizes of moments...

  4. Electrocatalytic CO2 reduction catalyzed by nitrogenase MoFe and FeFe proteins.

    Science.gov (United States)

    Hu, Bo; Harris, Derek F; Dean, Dennis R; Liu, T Leo; Yang, Zhi-Yong; Seefeldt, Lance C

    2017-12-05

    Nitrogenases catalyze biological dinitrogen (N2) reduction to ammonia (NH3), and also reduce a number of non-physiological substrates, including carbon dioxide (CO2) to formate (HCOO-) and methane (CH4). Three versions of nitrogenase are known (Mo-, V-, and Fe-nitrogenase), each showing different reactivities towards various substrates. Normally, electrons for substrate reduction are delivered by the Fe protein component of nitrogenase, with energy coming from the hydrolysis of 2 ATP to 2 ADP+2 Pi for each electron transferred. Recently, it has been demonstrated that energy and electrons can be delivered from an electrode to the catalytic nitrogenase MoFe-protein without the need for Fe protein or ATP hydrolysis. Here, it is demonstrated that both the MoFe- and FeFe-protein can be immobilized as a polymer layer on an electrode and that electron transfer mediated by cobaltocene can drive CO2 reduction to formate in this system. It was also found that the FeFe-protein diverts a greater percentage of electrons to CO2 reduction versus proton reduction compared to the MoFe-protein. Quantification of electron flow to products exhibited Faradaic efficiencies of CO2 conversion to formate of 9% for MoFe protein and 32% for FeFe-protein, with the remaining electrons going to proton reduction to make H2. Copyright © 2017. Published by Elsevier B.V.

  5. ¿Para quién y para qué son buenas las buenas prácticas? Unión Europea, integración de (in migrantes y despolitización/tecnificación de las políticas hegemónicas: un estudio de caso

    Directory of Open Access Journals (Sweden)

    Luca Sebastiani

    2017-01-01

    Full Text Available Entre finales de los años noventa y comienzos del nuevo siglo se ha ido afirmando un marco político en el ámbito de la Unión Europea, el cual fomenta el alcance de un entendimiento común de la integración de inmigrantes y promueve la coordinación, financiación e intercambio de información y “buenas prácticas” entre los diferentes niveles institucionales afectados, a través de herramientas de “políticas blandas” (soft policy. En este artículo analizaré y discutiré algunas de las consecuencias más relevantes originadas del entendimiento del concepto de “integración” por los principales actores implicados en este proceso, utilizando como ejemplo el caso de las “buenas prácticas” debido a su importancia dentro de los mecanismos de la “gobernanza multinivel” comunitaria. A través de este análisis, resaltaré que en el contexto comunitario, la noción de integración ha sido construida a través de un ejercicio de (aparente despolitización y tecnificación, cuyos resultados sin embargo son contradictorios -puesto que el elemento político a menudo retorna y se manifiesta “en el trasfondo”, “al margen” y “dentro” de lo técnico- a la vez que eficaces -en tanto en cuanto este ejercicio ha conseguido impulsar y moldear ciertas formas de saber, hablar y actuar sobre la integración de inmigrantes, naturalizando determinadas relaciones de poder existentes en la sociedad- . El material empírico para el presente artículo está basado en el trabajo de campo realizado en Bruselas entre 2011 y 2012 para la investigación doctoral. Consiste en entrevistas a los actores sociales y políticos más importantes del marco comunitario de la integración, en la observación de distintos encuentros y en la lectura de fuentes variadas.

  6. Study of the effects of metalloid elements (P, C, B) on Fe-based amorphous alloys by ab initio molecular dynamics simulations

    Science.gov (United States)

    Zhang, Wenbiao; Li, Qiang; Duan, Haiming

    2015-03-01

    In order to understand the effects of the metalloid elements M (M: P, C, B) on the atomic structure, glass formation ability (GFA) and magnetic properties of Fe-based amorphous alloys, Fe80P13C7, Fe80P14B6 and Fe80B14C6 amorphous alloys are chosen to study through first-principle simulations in the present work. The atomic structure characteristic of the three amorphous alloys is investigated through the pair distribution functions (PDFs) and Voronoi Polyhedra (VPs) analyses. The PDFs and VPs analyses suggest that the GFA of the three alloys dropped in the order of Fe80P13C7, Fe80P14B6, and Fe80B14C6, which is well consistent with the experimental results. The density of state (DOS) of the three amorphous alloys is calculated to investigate their magnetic properties. Based on the DOS analysis, the average magnetic moment of Fe atom in Fe80P13C7 and Fe80P14B6 amorphous alloys can be estimated to be 1.71 μB and 1.70 μB, respectively, which are in acceptable agreement with the experimental results. However, the calculated average magnetic moment of Fe atom in Fe80B14C6 amorphous alloy is about 1.62 μB, which is far less than the experimental result.

  7. A WRKY Transcription Factor Regulates Fe Translocation under Fe Deficiency.

    Science.gov (United States)

    Yan, Jing Ying; Li, Chun Xiao; Sun, Li; Ren, Jiang Yuan; Li, Gui Xin; Ding, Zhong Jie; Zheng, Shao Jian

    2016-07-01

    Iron (Fe) deficiency affects plant growth and development, leading to reduction of crop yields and quality. Although the regulation of Fe uptake under Fe deficiency has been well studied in the past decade, the regulatory mechanism of Fe translocation inside the plants remains unknown. Here, we show that a WRKY transcription factor WRKY46 is involved in response to Fe deficiency. Lack of WRKY46 (wrky46-1 and wrky46-2 loss-of-function mutants) significantly affects Fe translocation from root to shoot and thus causes obvious chlorosis on the new leaves under Fe deficiency. Gene expression analysis reveals that expression of a nodulin-like gene (VACUOLAR IRON TRANSPORTER1-LIKE1 [VITL1]) is dramatically increased in wrky46-1 mutant. VITL1 expression is inhibited by Fe deficiency, while the expression of WRKY46 is induced in the root stele. Moreover, down-regulation of VITL1 expression can restore the chlorosis phenotype on wrky46-1 under Fe deficiency. Further yeast one-hybrid and chromatin immunoprecipitation experiments indicate that WRKY46 is capable of binding to the specific W-boxes present in the VITL1 promoter. In summary, our results demonstrate that WRKY46 plays an important role in the control of root-to-shoot Fe translocation under Fe deficiency condition via direct regulation of VITL1 transcript levels. © 2016 American Society of Plant Biologists. All Rights Reserved.

  8. Intervenciones preventivas de la violencia interna en el trabajo: políticas de buenas prácticas y gestión de conflictos

    Directory of Open Access Journals (Sweden)

    Antonia Bernat Jiménez

    Full Text Available La violencia interna en el lugar de trabajo es la que tiene lugar entre los trabajadores, incluidos mandos y directivos. Incluye la violencia física, el acoso sexual y el acoso psicológico, abarcando también otras conductas de violencia psicológica diferenciadas de éste. Debe ser considerada como un riesgo psicosocial, que supone un peligro importante para la salud y seguridad de las personas, y tiene repercusiones organizacionales a través de costes directos e indirectos. Considerar la violencia interna con este enfoque de riesgo laboral, supone que su abordaje se ha de realizar aplicando los principios de la acción preventiva, a la vez que permite adoptar estrategias de actuación dirigidas a la prevención del fenómeno. Las principales organizaciones a nivel mundial y nacional proponen la implementación de una política de prevención de la violencia en el lugar de trabajo. Este artículo trata sobre la conveniencia del desarrollo e implementación en las organizaciones de una política de prevención de la violencia interna, de carácter integral e integrado, que involucre a toda la organización, orientada a lograr entornos de trabajo más saludables y con un enfoque centrado en los factores organizativos y psicosociales. En el artículo se contemplan las premisas esenciales de esa política preventiva de la violencia interna, abordándose también los momentos básicos de la estrategia preventiva: - La evaluación de riesgo psicosociales. - La política de buenas prácticas. - Los procedimientos de gestión de conflictos y acoso psicológico en el trabajo. - Las estrategias de comunicación organizacional y las acciones formativas. Para conseguir auténtica efectividad, las políticas de prevención de la violencia interna deben incorporarse al Sistema de Gestión de la Prevención de la organización, que, a su vez, estará integrado en todos los sistemas de gestión restantes de la empresa.

  9. Aplicación de un Programa de Inspección de Calidad acorde con las Buenas Prácticas de Laboratorio

    Directory of Open Access Journals (Sweden)

    Mayra Castro Nodal

    2002-08-01

    Full Text Available El proceso de diseño e implementación de un Sistema de Calidad, una de las actividades más importantes y de especial interés lo constituye el sistema de monitoreo mediante el cual se controle o chequee su cumplimiento. El Centro de Química Farmacéutica con el fin de garantizar la calidad, credibilidad e integridad de sus resultados, ha diseñado e implantado un Sistema de Calidad basado en el cumplimiento de las Buenas Prácticas de Laboratorio que es monitoreado mediante la ejecución de un Programa de Inspecciones que abarca todos los objetos de inspección vinculados a la norma de referencia. La ejecución se controla por medio de un Sistema Automatizado de Gestión, con el empleo del Programa Microsoft Access 97, lo que permite incrementar la organización y la eficiencia de esta actividad, además de facilitar la emisión de la información relacionada con este sistema. La aplicación de dicho programa ha contribuido a elevar la calidad de los resultados.In the process of designing and implementing a Quality System, one of the most important and specially interesting activities is the monitoring systems that controls or checks compliance with the quality system. The Pharmaceutics Chemistry Center, with the aim of assuring quality, credibility and integrity of its results, has designed and implemented a Good Lab Practice-based Quality System that is monitored thanks to the implementation of an Inspection Program embracing all objects of inspection linked to the referred standard. The operation is controlled by an Automated Management System using Microsoft Access 97; this makes it possible to increase the organization and efficiency of this activity in addition to facilitating the output of data related to this system. The application of such a program has contributed to raise the quality of the results.

  10. Magnetic interactions and spin configuration in FeRh and Fe/FeRh systems

    Energy Technology Data Exchange (ETDEWEB)

    Kuncser, V. E-mail: kuncser@alpha2.infim.ro; Keune, W.; Sahoo, B.; Duman, E.; Acet, M.; Radu, F.; Valeanu, M.; Crisan, O.; Filoti, G

    2004-05-01

    The magnetic interactions and the Fe spin structure have been studied in Fe(6 nm)/FeRh systems by magnetometry, magneto-optic Kerr effect and conversion electron Moessbauer spectroscopy. A spin-flop coupling mechanism, with the interfacial spins of the ferromagnetic phase perpendicular to the spins of the antiferromagnetic phase was experimentally proved.

  11. Dos nuevas especies y dos nuevas variedades de Columnea (Gesneriaceae

    Directory of Open Access Journals (Sweden)

    MARISOL AMAYA-MÁRQUEZ

    2015-01-01

    Full Text Available En este artículo describimos dos nuevas especies de Gesneriaceae (género Columnea. Columnea chocoensis se encuentra distribuida en los departamentos de Chocó y Valle del Cauca en Colombia, y C. chocoensis var. altaquerensis se distribuye en el departamento de Nariño, Colombia. Columnea stilesiana fue hallada en La Serranía de Los Paraguas localizada en la Cordillera Occidental entre los departamentos de Chocó y Valle del Cauca en Colombia. Adicionalmente, aquí se considera a Columnea archidonae como variedad de C. ericae. Columnea ericae var. archidonae se distribuye en Colombia y Ecuador, en bosques de mayor altura que aquellos en los cuales se encuentra la variedad típica.

  12. Armonización de estándares de calidad para ensayos clínicos. Norma ISO 9001-Guía de Buena Práctica Clínica

    Directory of Open Access Journals (Sweden)

    Sandra Álvarez Guerra

    2011-09-01

    Full Text Available El proceso de ensayo clínico necesario para autorizar el uso de nuevos medicamentos en humanos es extenso y complejo. Para garantizar la calidad y estandarizar este proceso, la Conferencia Internacional de Armonización ha establecido la Guía E6 para la Buena Práctica Clínica, la cual ha sido asumida y adaptada por las agencias reguladoras nacionales para estandarizar este proceso en sus países. Otra norma que permite garantizar calidad es la ISO 9001:2008, que establece requisitos para implementar Sistema de Gestión de Calidad. El objetivo de este trabajo consistió en establecer elementos comunes que demuestren la armonización entre la Buena Práctica Clínica de la Conferencia Internacional de Armonización, la Buena Práctica Clínica cubana y la ISO 9001:2008 para su implementación en sistemas de calidad para los ensayos clínicos. Para ello se realizó el estudio de estos estándares analizando qué tienen en común en su aplicación para el proceso de ensayo clínico. Se determinó que el cliente, los proveedores, el enfoque de proceso, la documentación, la dirección, las revisiones, la forma de realización de la investigación y la mejora de la calidad son puntos comunes para los cuales se establecen requisitos a cumplir. Esto permitió afirmar que los estándares estudiados al ser usados de conjunto en el proceso de ensayo clínico, contribuyen a elevar la calidad, pues no existe ningún aspecto contemplado en ellos que refleje contradicción sino aspectos comunes que permiten su armonización y uso.

  13. Estudio hidrogeológico y de calidad de agua en el sector oriental de la Sierra de San Javier entre las localidades de Yerba Buena y el Manantial. Provincia de Tucuman, Republica Argentina

    Directory of Open Access Journals (Sweden)

    D’Urso, C. H.

    2005-12-01

    Full Text Available The study area is located in the center west of the county of Tucumán, in the NW of Argentina. It extends from the oriental border of San Javier’s mountain between the towns of Yerba Buena and Manantial. In the piedmont zone and plain, have settled down diverse urban, agricultural centers and an important industrial complex that are supplied by underground water. The objective of this paper is to define the different geologic factors that impact in the behavior of the underground water and to define areas with appropriate hydrogeological characteristics for its use. The investigation determined that the water contained in the aquifers is of good quality and due to the high permeability, important flows can be obtained, that guarantee the supply to the population, agriculture and industry.La zona de estudio está ubicada en el centro oeste de la provincia de Tucumán, en el noroeste de Argentina. Se extiende desde el borde oriental de la sierra de San Javier entre las localidades de Yerba Buena y el Manantial. En el piedemonte y llanura se han establecido diversos centros urbanos, agrícolas y un importante complejo industrial que se abastecen de agua subterránea. El objetivo del trabajo es delimitar los distintos factores geológicos que inciden en el comportamiento del agua subterránea y tratar de definir zonas con características hidrogeológicas apropiadas para su aprovechamiento. De esta investigación se determinó que el agua que contienen los acuíferos es de buena calidad y debido a la elevada permeabilidad de los mismos, se pueden obtener importantes caudales, con lo que se garantiza el abastecimiento a la población, agricultura e industria.

  14. ORGANIZATIONAL GOOD PRACTICES FOR THE INTEGRATION OF THE ICT IN THE EDUCATION SYSTEM OF EXTREMADURA BUENAS PRÁCTICAS ORGANIZATIVAS PARA LA INTEGRACIÓN DE LAS TIC EN EL SISTEMA EDUCATIVO EXTREMEÑO

    Directory of Open Access Journals (Sweden)

    Mª José Sosa Díaz

    2010-02-01

    Full Text Available The present paper tries to release some organizational Good Practices for the integration of the ICT's carried out by the Education System in Extremadura. For this, in a first moment, a theoretical review about the concept of Good Practices has been done, establishing some indicators which permit us identify Good Practices regarding the application of the ICT within Primary and Secondary schools, and specially pointing out the indicators that refer to organizational aspects in the educational establishments and classrooms. Secondly, the politics for the integration of New Technologies conducted by Junta de Extremadura are analyzed, emphasizing the figure of the ICT Coordinator as a quality measure, as well as the technological tools for school management and controlling the classes. Finally, we present the results obtained from several interviews that were made to different members of the school community, all in a broader investigation where diverse case studies of Primary and Secondary schools considered as Good Practices with ICT were effectuated.En el presente trabajo se pretende dar a conocer Buenas Prácticas de tipo organizativo para la integración de las TIC que ha llevado a cabo el Sistema Educativo Extremeño. Para ello, en un primer momento, se ha realizado una revisión teórica sobre el concepto de Buenas Prácticas, estableciendo algunos indicadores que nos permitan identificar Buenas Prácticas en el uso de las TIC en los centros educativos de Primaria y Secundaria, y destacando especialmente aquellos indicadores que hacen referencia a aspectos organizativos del centro y de las aulas. En segundo lugar, se ha efectuado un análisis de la política de integración de las tecnologías que ha llevado a cabo la Junta de Extremadura, enfatizando en la figura del/la Coordinador/a TIC como medida de calidad, así como en las herramientas tecnológicas de gestión del centro y control del aula. Por último, se presentan algunos resultados

  15. Diseño y mejora de los sistemas de administración, procesos de producción y buenas prácticas de manufactura en la empresa AVICEV

    OpenAIRE

    Cevallos Larrea, Juan Carlos

    2011-01-01

    El documento consiste en diseñar un sistema para administrar la empresa AVICEV, complementándose con el diseño y mejora de los procesos productivos y desarrollo de buenas prácticas de manufactura para buscar mejorar la calidad del producto y ser más competitivos en el mercado luego de aplicar la metodología propuesta. This document is to design a system to manage the company AVICEV, complemented with the design and improvement of production processes and development of good manufacturing p...

  16. Strain effects on electronic structure of Fe{sub 0.75}Ru{sub 0.25}Te

    Energy Technology Data Exchange (ETDEWEB)

    Winiarski, M.J., E-mail: M.Winiarski@int.pan.wroc.pl [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422, Wrocław (Poland); Samsel-Czekała, M. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-422, Wrocław (Poland); Ciechan, A. [Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, 02-668, Warsaw (Poland)

    2017-01-15

    Structural and electronic properties of a hypothetical Fe{sub 0.75}Ru{sub 0.25}Te alloy and the parent FeTe compound have been investigated from first principles within the density functional theory (DFT). For both systems the double-stripe antiferromagnetic ground state is predicted at ambient pressure. The incorporation of Ru atoms into FeTe in the nonmagnetic phase leads to a deep valley of density of states in the vicinity of the Fermi level and the DOS at the Fermi level is significantly diminished in the considered solid solution. The single-stripe antiferromagnetic phase in Fe{sub 0.75}Ru{sub 0.25}Te may be induced by tensile strain. These findings suggest that strained thin films of Fe{sub 1−x}Ru{sub x}Te are good candidates for new superconducting Fe-based materials. - Highlights: • Ru-doped FeTe systems are investigated by density-functional theory methods. • Structural and electronic properties of Fe{sub 0.75}Ru{sub 0.25}Te and parent FeTe are studied. • The double-stripe antiferromagnetic ground state is predicted for both systems. • The single-stripe antiferromagnetic phase may be induced by tensile strain. • Tensile strained Fe{sub 0.75}Ru{sub 0.25}Te is a candidate for a new Fe-based superconductor.

  17. Neumonía eosinofílica: presentación de dos casos, agudo y crónico

    Directory of Open Access Journals (Sweden)

    Oscar Pamo Reyna

    2007-01-01

    Full Text Available Se presenta dos casos de neumonía eosinofílica idiopática, uno crónico y otro agudo. En el caso clínico 1 se realizó una confirmación anatomopatológica de neumonía eosinofílica idiopática y en el caso clínico 2 se tuvo una neumonia eosinofílica aguda probable. Ambos presentaron tos, fiebre y disnea. El estudio radiográfico reveló lesiones alveolares bilaterales con tendencia a la consolidación. La marcada eosinofilia en sangre periférica fue un dato resaltante que facilitó el diagnóstico. Ambos casos tuvieron muy buena respuesta a la corticoterapia.(Rev Med Hered 2007;18:39-44.

  18. Aproximación al riesgo de inundación en dos diputaciones de la ciudad de Cartagena (Murcia, España

    Directory of Open Access Journals (Sweden)

    Yolanda Álvarez Rogel

    2010-01-01

    Full Text Available Las inundaciones son un fenómeno recurrente en buena parte de la ciudad de Cartagena. Un modelo digital de elevaciones permite identificar áreas urbanas en cotas muy próximas a cero metros y bajo el nivel del mar, por tanto potencialmente inundables, que engloban barriadas de dos diputaciones. La ubicación de las mismas en relación a la red de drenaje y los materiales sobre los que se asientan apuntan causas que explican la recurrencia del fenómeno inundación. A su vez, entrevistas mantenidas con ciudadanos residentes permiten conocer cómo se percibe el riesgo que la inundación comporta.

  19. O surgimento dos direitos republicanos

    Directory of Open Access Journals (Sweden)

    Amanda Cristina Carvalho Canezin

    2015-09-01

    Full Text Available O capítulo 8 do livro “Construindo o Estado Republicano: Democracia e reforma da Gestão Pública” do autor Luiz Carlos Bresser-Pereira, tem como tema central o republicanismo. Abordado sob uma perspectiva histórica, o surgimento dos direitos republicanos no Estado ocorreu durante o século XX, influenciado por dois importantes fatos, quais sejam a globalização e a democracia.A obra sugere um estudo sobre a origem do novo Estado democrático, bem como sobre a reforma da gestão pública, abrangendo aspectos políticos, econômicos, enfatizando o direito.O autor inicia o capítulo em análise abrangendo os direitos republicanos, retomando os ideais republicanos dos filósofos e teóricos políticos. No momento em que se observava a retomada do republicanismo notou-se que o mesmo estava efetivado em prática política de cidadãos organizados em uma sociedade civil, onde o cidadão participaria de forma efetiva no Estado ao qual faz parte.Para Bresses-Pereira, direitos republicanos são os direitos assegurados a todos os cidadãos tem ao uso público da res publica – do patrimônio público – inclusive o fluxo de recursos envolvidos nas receitas do Estado e das organizações públicas não-estatais.Denota-se assim que, os direitos republicanos são efetivados no momento em que os cidadãos acastelam o patrimônio público contra as tentativas de captura por indivíduos poderosos. A ampliação da res publica, representada por um terço e por metade da renda de todos os países, fez despertar uma cobiça ainda maior de indivíduos e grupos pelos patrimônios públicos, tornando sua proteção essencial.Novas ferramentas surgiram em defesa da res publica, quando a democracia se tornou o regime político dominante. E assim, se pode dizer que o surgimento dos direitos republicanos e a consolidação da democracia como o regime político dominante fazem parte de um mesmo processo histórico. A democracia transformou-se em “um valor

  20. Fe de Erratas

    Directory of Open Access Journals (Sweden)

    Perspectiva Geográfica

    2014-01-01

    Full Text Available La Magíster Sonia Jimena Murillo Munar, autora del artículo titulado “Transporte urbano sostenible: medidas desde la administración y transporte público como alternativa en Bogotá”, publicado en el Volumen No. 13 correspondiente al año 2008, solicita la inclusión de la siguiente FE DE ERRATAS con la enmienda de un error de exclusiva responsabilidad del Equipo Editorial de la Revista.

  1. Dehydrogenation Properties of Magnesium Hydride Loaded with Fe, Fe-C, and Fe-Mg Additives.

    Science.gov (United States)

    Pukazhselvan, D; Nasani, Narendar; Yang, Tao; Bdikin, Igor; Kovalevsky, Andrei V; Fagg, Duncan P

    2017-02-02

    This study highlights that Fe additives offer better catalytic properties than carbon, Fe-C (iron carbide/carbon composites), and Fe-Mg (Mg2 FeH6 ) additives for the low-temperature dehydrogenation of magnesium hydride. The in situ X-ray diffraction measurements prove the formation of a Mg2 FeH6 phase in iron additive loaded MgH2 . Nonetheless, differential scanning calorimetry data suggest that this Mg2 FeH6 phase does not have any influence on dehydrogenation properties of MgH2 . On the other hand, the composite system Mg2 FeH6 /MgH2 shows significantly improved dehydrogenation properties even in absence of further additives. It is suggested that the improved system performance of Fe loaded MgH2 is attributed to restrictions on crystal growth of MgH2 and the catalytic behavior of Fe nanoparticles, rather than any intrinsic catalytic properties offered by the formed mixed metal phase Mg2 FeH6 . © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Bienes y servicios ambientales: Mercados no tradicionales, mecanismos de financiamiento y buenas prácticas en América Latina y el Caribe: Actividad 2: Buenas prácticas en la aplicación de mecanismos de financiamiento para la obtención de servicios ambientales de prácticas forestales y agrícolas sostenibles en América Latina y el Caribe

    OpenAIRE

    Francisco Alpízar; Róger Madrigal; Marco Otárola; Pérez, Carlos J.; Ricardo González-Jiménez; Mario Niklitschek

    2006-01-01

    Esta es la última versión disponible de este documento que fue comisionado por la Red de Medio Ambiente del Diálogo Regional de Política. El desarrollo del trabajo de esta consultoría consistió de tres actividades principales. Este informe hace referencia a la actividad 2, la cual tiene como objetivo mostrar buenas prácticas en la aplicación de mecanismos de financiamiento para la obtención de servicios ambientales de prácticas forestales y agrícolas sostenibles en América Latina y el Caribe....

  3. Fe in magma - An overview

    Directory of Open Access Journals (Sweden)

    M. Wilke

    2005-06-01

    Full Text Available The strong influence of physical conditions during magma formation on Fe equilibria offers a large variety of possibilities to deduce these conditions from Fe-bearing phases and phase assemblages found in magmatic rocks. Conditions of magma genesis and their evolution are of major interest for the understanding of volcanic eruptions. A brief overview on the most common methods used is given together with potential problems and limitations. Fe equilibria are not only sensitive to changes in intensive parameters (especially T and fO2 and extensive parameters like composition also have major effects, so that direct application of experimentally calibrated equilibria to natural systems is not always possible. Best estimates for pre-eruptive conditions are certainly achieved by studies that relate field observations directly to experimental observations for the composition of interest using as many constraints as possible (phase stability relations, Fe-Ti oxides, Fe partitioning between phases, Fe oxidation state in glass etc.. Local structural environment of Fe in silicate melts is an important parameter that is needed to understand the relationship between melt transport properties and melt structure. Assignment of Fe co-ordination and its relationship to the oxidation state seems not to be straightforward. In addition, there is considerable evidence that the co-ordination of Fe in glass differs from that in the melt, which has to be taken into account when linking melt structure to physical properties of silicate melts at T and P.

  4. Os Fungos no Funcionamento dos Ecossistemas Florestais

    OpenAIRE

    Santos-Silva, Celeste; Machado, Helena

    2011-01-01

    Os fungos no funcionamento dos ecossistemas Florestais: Papel dos fungos sapróbios na degradação da matériaorgânica Papel dos fungos micorrízicos na nutrição e saúde das árvores Diversidade fúngica e estabilidade das florestas Relações entre os fungos e os animais Doenças radiculares associadas ao declínio do montado de sobro e azinho

  5. Fe65-PTB2 Dimerization Mimics Fe65-APP Interaction

    Directory of Open Access Journals (Sweden)

    Lukas P. Feilen

    2017-05-01

    Full Text Available Physiological function and pathology of the Alzheimer’s disease causing amyloid precursor protein (APP are correlated with its cytosolic adaptor Fe65 encompassing a WW and two phosphotyrosine-binding domains (PTBs. The C-terminal Fe65-PTB2 binds a large portion of the APP intracellular domain (AICD including the GYENPTY internalization sequence fingerprint. AICD binding to Fe65-PTB2 opens an intra-molecular interaction causing a structural change and altering Fe65 activity. Here we show that in the absence of the AICD, Fe65-PTB2 forms a homodimer in solution and determine its crystal structure at 2.6 Å resolution. Dimerization involves the unwinding of a C-terminal α-helix that mimics binding of the AICD internalization sequence, thus shielding the hydrophobic binding pocket. Specific dimer formation is validated by nuclear magnetic resonance (NMR techniques and cell-based analyses reveal that Fe65-PTB2 together with the WW domain are necessary and sufficient for dimerization. Together, our data demonstrate that Fe65 dimerizes via its APP interaction site, suggesting that besides intra- also intermolecular interactions between Fe65 molecules contribute to homeostatic regulation of APP mediated signaling.

  6. Magnetic properties of Fe1-xMnx/Fe nanocomposites

    DEFF Research Database (Denmark)

    Anhøj, Thomas Aarøe; Jacobsen, Claus Schelde; Mørup, Steen

    2004-01-01

    We have prepared nanocomposites of mixtures of ferromagnetic alpha-Fe and antiferromagnetic gamma-Fe50Mn50 nanoparticles, and studied their magnetic and structural properties by magnetization measurements, Mössbauer spectroscopy, and x-ray diffraction. A sample consisting of a 1:1 mixture of the ...... are discussed. ©2004 American Institute of Physics....

  7. Tunnel Magneto Resistance of Fe/Insulator/Fe

    Science.gov (United States)

    Aryee, Dennis; Seifu, Dereje

    Tri-layer thin films of Fe/Insulator/Fe were synthesized using magnetron DC/ RF sputtering with MgO insulator and Bi2Te3 topological insulators as middle buffer layer. The multi-layered samples thus produced were studied using in-house built magneto-optic Kerr effect (MOKE) instrument, vibrating sample magnetometer (VSM), torque magnetometer (TMM), AFM, MFM, and magneto-resistance (MR). This system, that is Fe/Insulator/Fe on MgO(100) substrate, is a well-known tunnel magneto resistance (TMR) structure often used in magnetic tunnel junction (MTJ) devices. TMR effect is a method by which MTJs are used in developing magneto-resistive random access memory (MRAM), magnetic sensors, and novel logic devices. The main purpose behind this research is to measure the magnetic anisotropy of Fe/Insulator /Fe structure and correlate it to magneto-resistance. In this presentation, we will present results from MOKE, VSM, TMM, AFM, MFM, and MR studies of Fe/Insulator/Fe on MgO(100). We would like to acknowledge support by NSF-MRI-DMR-1337339.

  8. Dos generaciones de nativos digitales

    Directory of Open Access Journals (Sweden)

    Joaquín Linne

    Full Text Available A partir de encuestas, entrevistas y observaciones en la Ciudad Autónoma de Buenos Aires, afirmamos que existen dos generaciones de nativos digitales (ND: los jóvenes 1.0 y los adolescentes 2.0. Si bien ambas comparten características comunes, los 2.0 poseen rasgos propios: son una generación post-mail, suelen haberse criado alrededor de entornos digitales y manifiestan de modo online sus aspectos íntimos. Estos contenidos personales, que comparten con su grupo de pares a través de sitios de redes sociales, expresan una nueva concepción de la intimidad que podemos denominar "multimidad". A su vez, dividimos a los ND 2.0 según su nivel de alfabetización digital, condicionado por su entorno tecnológico, su capital cultural y su uso de las TIC, con el objetivo de brindar herramientas analíticas que contribuyan a mejorar las políticas públicas de inclusión digital.

  9. Dolo y mala fe

    Directory of Open Access Journals (Sweden)

    Carlos Arturo Gómez Pavajeau

    2010-12-01

    Full Text Available Se ha dicho por grandes penalistas que las tesis en nuestra disciplina son una eterna vuelta al pasado. Empero, debe constatarse, que ello se ha dicho en un sentido de lo clásico: una vuelta a lo que resulta digno de admirar en cualquier época, toda vez que las experiencias históricas negativas nos previenen de repetir el pasado, razón fundamental por la cual debemos conocerlo. En este escrito pretendemos mostrar cómo algunas tendencias actuales nos indican que épocas nefastas ya superadas pueden repetirse, lo cual particularmente sucede tanto con la noción de dolo como con la de mala fe, concepto que de imponerse destruiría, a la manera como se derrumba un castillo de naipes, el sólido edificio dogmático construido por el Derecho penal liberal.

  10. Roles of Fe-Nx and Fe-Fe3C@C Species in Fe-N/C Electrocatalysts for Oxygen Reduction Reaction.

    Science.gov (United States)

    Kim, Jae Hyung; Sa, Young Jin; Jeong, Hu Young; Joo, Sang Hoon

    2017-03-22

    Iron and nitrogen codoped carbons (Fe-N/C) have emerged as promising nonprecious metal catalysts for the oxygen reduction reaction (ORR). While Fe-Nx sites have been widely considered as active species for Fe-N/C catalysts, very recently, iron and/or iron carbide encased with carbon shells (Fe-Fe3C@C) has been suggested as a new active site for the ORR. However, most of synthetic routes to Fe-N/C catalysts involve high-temperature pyrolysis, which unavoidably yield both Fe-Nx and Fe-Fe3C@C species, hampering the identification of exclusive role of each species. Herein, in order to establish the respective roles of Fe-Nx and Fe-Fe3C@C sites we rationally designed model catalysts via the phase conversion reactions of Fe3O4 nanoparticles supported on carbon nanotubes. The resulting catalysts selectively contained Fe-Nx, Fe-Fe3C@C, and N-doped carbon (C-Nx) sites. It was revealed that Fe-Nx sites dominantly catalyze ORR via 4-electron (4 e(-)) pathway, exerting a major role for high ORR activity, whereas Fe-Fe3C@C sites mainly promote 2 e(-) reduction of oxygen followed by 2 e(-) peroxide reduction, playing an auxiliary role.

  11. Cuidados Centrados na Família: impacto da formação e de um manual de boas práticas em pediatria Cuidados Centrados en la Familia: impacto de la formación y de un manual de buenas prácticas en pediatria Family-centered care: impact of training and a best practice guide in pediatrics

    Directory of Open Access Journals (Sweden)

    Marta Isabel Correia Gaio Apolinário

    2012-07-01

    Full Text Available Os Cuidados Centrados na Família (CCF constituem uma nova conceção do cuidar pediátrico em que as necessidades das Famílias e Crianças são centrais nesse processo. No entanto, na prática, a sua aplicação nas unidades hospitalares é ainda deficiente, sendo emergente o empenho para que esta filosofia de cuidados se efetive na prática diária dos Enfermeiros. Realizou-se um estudo quase experimental tipo pré teste, pós teste sem grupo de controlo, baseado numa metodologia quantitativa, cujos objetivos foram avaliar o impacto da formação e de um manual de boas práticas nos conhecimentos dos Enfermeiros e na sua perceção quanto à aplicação dos CCF em Pediatria. Da amostra fizeram parte 24 Enfermeiros de um serviço de pediatria a quem foram aplicados três questionários. Confirmou-se que existe diferença positiva nos conhecimentos dos Enfermeiros sobre os CCF e na sua perceção quanto à aplicação desta filosofia na prática diária antes e depois da formação e da implementação do manual de boas práticas, o que demonstra o impacto e eficácia da intervenção desenvolvida na efetivação desta filosofia nas unidades pediátricas.Los cuidados centrados en la familia (CCF constituyen una nueva concepción del cuidar pediátrico en que las necesidades de las familias y de los niños son centrales en dicho proceso. Sin embargo, en realidad, su aplicación en las unidades hospitalarias sigue siendo insuficiente, a pesar de que haya surgido un esfuerzo para que esta filosofía de atención forme parte efectiva de la práctica diaria de los enfermeros. Se realizó un estudio casi experimental, de tipo pre-test y con un post-test sin grupo de control, basado en una metodología cuantitativa, cuyos objetivos fueron evaluar el impacto de la formación y de un manual de buenas prácticas en los conocimientos de los enfermeros y en su percepción con respecto a la aplicación de los CCF en pediatría. La muestra consistió en 24

  12. BUENAS PRÁCTICAS DE INNOVACION: UN ESTUDIO EXPLORATORIO DE EMPRESAS TECNOLÓGICAS EN EL SECTOR AUDIOVISUAL ESPAÑOL

    Directory of Open Access Journals (Sweden)

    Suñe, Albert

    2012-05-01

    Full Text Available El principal objetivo de esta investigación es contribuir a la comprensión de la capacidad de innovación. Más concretamente, la investigación se centra en describir las prácticas utilizadas para construir y desarrollar la capacidad de innovación en dos empresas innovadoras de base tecnológica (EIBT del sector audiovisual español. Por medio de un estudio de casos múltiple basado, principalmente, en entrevistas con los responsables de los proyectos de desarrollo de nuevos productos, se ha identificado un conjunto de 17 prácticas clasificadas en tres dimensiones: estrategia de innovación, cultura innovadora y estructura del proceso de innovación. Este conjunto de prácticas ha promovido la obtención de buenos resultados en los proyectos de desarrollo de nuevos productos en las empresas estudiadas.

  13. Hormigas (Hymenoptera: Formicidae de la provincia de Santa Fe, Argentina Ants (Hymenoptera: Formicidae of Santa Fe province, Argentina

    Directory of Open Access Journals (Sweden)

    Fernando Vittar

    2008-06-01

    Full Text Available El presente trabajo pretende aportar una lista faunística actualizada de las subfamilias, tribus, géneros y especies de hormigas de la provincia de Santa Fe, Argentina. Si bien estos listados tienen poca duración temporal, contribuyen en gran medida a incrementar el conocimiento de un taxón determinado, despertando interés y brindando una herramienta fundamental para el desarrollo de estudios posteriores. Como resultado, nueve registros son nuevos para la Argentina y dos géneros y 18 citas de especies nuevas para la provincia de Santa Fe.The present paper provides an updated faunistic list of the subfamilies, tribes, genera and species of ants of Santa Fe province, Argentina. To a great extent, these listings contribute to increase the knowledge of a specific taxa, awaking interest, and offering a fundamental tool for the development of subsequent studies. As a result, nine species are cited as new for Argentina, and two genera and 18 species are cited for Santa Fe province for the first time.

  14. Good faith en el ejercicio de poderes contractuales discrecionales (¿Un punto de contacto entre Common Law y Civil Law?

    Directory of Open Access Journals (Sweden)

    Javier Humberto Facco

    2012-06-01

    Full Text Available La buena fe es no solo uno de los dos polos de la definición celsina del derecho, sino también quizás el más relevante principio general de la tradición jurídica continental-europea. Herencia directa del mundo romano, la buena fe ha recobrado su posición central en particular en la teoría de las obligaciones y contratos, donde encuentra su mayor desarrollo. En los tiempos que corren la buena fe ha sido también objeto de análisis y consideración en ámbito de la tradición del derecho anglo-americano. Precisamente este artículo busca señalar zonas de contacto entre las dos tradiciones en materia de buena fe y su relación con la libertad contractual, sus efectos en la exigibilidad de la prestación, la determinación del precio, las modalidades de la ejecución del contrato y el ejercicio de la discrecionalidad de las partes. Este análisis sugiere al lector las cuestiones de la buena fe y las razonables previsiones de las partes en el tejido contractual, y de allí su relación con las fuentes de integración del contrato.

  15. Desarrollo de materiales compuestos tipo Cermet de matriz Fe

    Directory of Open Access Journals (Sweden)

    Gordo, E.

    2004-04-01

    Full Text Available The objective of this study aims to the development of Fe-matrix composites with high carbide content to achieve properties between high-speed steels (HSS and cemented carbides. Cemented carbides are harder and show higher wear resistance than HSS, but lower toughness. Besides, the substitution of Co or Ni for other binders is desirable due to the carcinogen character of these metals. In this work, a material constituted by an iron matrix and a 50 % wt of WC and TaC carbides is developed. Highenergy milling has been used to obtain composite powders presenting a good bonding and homogeneous distribution of the carbides in the matrix. Those powders were characterised and compacted by die pressing. The green compacts were sintered at different temperatures, and properties like hardness and density were determined. Also, the wear behaviour was studied and microstructural analysis by SEM was carried out to complete the study.

    El objetivo de este trabajo es el desarrollo de materiales compuestos de matriz Fe con alto contenido en carburos con propiedades entre los aceros rápidos y los carburos cementados, ya que estos últimos son más duros y presentan mayor resistencia al desgaste que los primeros pero también menor tenacidad. Además, se hace deseable la sustitución de Co o Ni por otros aglomerantes debido a los riesgos medioambientales y para la salud que estos metales representan. En este trabajo se estudia la obtención de un material formado por una matriz de acero con adición de 50 % en masa de carburos de wolframio (WC y tantalio (TaC. Para ello se han utilizado técnicas de molienda de alta energía que permiten obtener un polvo compuesto con una buena unión metal-cerámica y una distribución homogénea de carburos en la matriz. Después de la caracterización del polvo compuesto se compactaron probetas en matriz uniaxial con objeto de estudiar la sinterabilidad del material. Los compactos fueron sinterizados en vacío a

  16. Ciencias sociales, Derecho Administrativo y buena gestión pública. De la lucha contra las inmunidades del poder a la batalla por un buen gobierno y una buena administración mediante un diálogo fructífero

    Directory of Open Access Journals (Sweden)

    Juli Ponce Solé

    2014-07-01

    Full Text Available El estudio partiendo de las más modernas corrientes doctrinales plantea cuál deba ser la relación entre el Derecho (administrativo y el resto de ciencias sociales. Partiendo de la existencia de una tradición fuertemente influenciada por puntos de vista jurídicos formalistas y, simultáneamente, del menosprecio a lo jurídico que puede percibirse tanto en la gestión pública cotidiana como en importantes perspectivas desde la ciencia política y otras ciencias sociales, el trabajo aborda la necesaria renovación epistemológica y metodológica de la doctrina administrativista, que aborde de modo distinto la clave de la actividad pública, el ejercicio de discrecionalidad, no concibiendo el papel de lo jurídico como un instrumento de control puramente negativo, sino también como una herramienta de orientación de ese ejercicio en pos de la buena administración y el buen gobierno en interacción, que no disolución, con otras ciencias sociales, de las cuales se distingue el Derecho, en definitiva, por tener los tribunales de justicia la última palabra sobre los conflictos que puedan generarse. The study deals with the relation between Law (administrative law and the rest of social sciences. On one hand, the study underlines the existence of a legal tradition strongly influences by formalistic approaches. On the other hand, , simultaneously, there is a lack of conscience of the importance of legal inputs in the daily public management as well as in relevant points of view from the academy in the area of political science and other social sciences. The work emphasizes the necessary epistemological and methodological renewal of the legal jurisprudence which should look at the key of the public activity in a distinct way: the use of discretionary powers. In that sense, the role of law not should be only an instrument of control purely negative but also a tool of orientation of this discretionary exercise looking for the good administration

  17. Maturation of [FeFe]-hydrogenases: Structures and mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Nicolet, Yvain; Fontecilla-Camps, Juan C. [Laboratoire de Cristallographie et Cristallogenese des Proteines, Institut de Biologie Structurale J.P. Ebel, Universite Joseph Fourier, Grenoble, CNRS, UMR 5075, CEA, DSV/IBS, 41 rue J. Horowitz F-38027 Grenoble cedex 1 (France); Fontecave, Marc [Laboratoire de Chimie et Biologie des Metaux; Universite Joseph Fourier, Grenoble, CNRS, UMR 5249, CEA, DSV/iRTSV, 17 rue des Martyrs F-38054 Grenoble cedex 9 (France); College de France, 11 place Marcelin-Berthelot 75231 Paris cedex 05 (France)

    2010-10-15

    Maturation of [FeFe]-hydrogenases, consisting in the synthesis and assembly of a di-iron center with a dithiolate bridging ligand as well as CO and CN ligands, depends on the concerted action of three metalloproteins, HydE, HydF and HydG. HydE and HydG are ''Radical-SAM'' enzymes involved in the synthesis of the ligands. HydF is proposed to function as a scaffold protein in which the di-iron center is assembled before being transferred to the hydrogenase. Here we review the current knowledge regarding the structure of the three maturases and the mechanisms of synthesis and assembly of the di-iron center of [FeFe]-hydrogenases. (author)

  18. Magnetism and structural phase transformation in Fe / Fe oxide nanopowders

    Energy Technology Data Exchange (ETDEWEB)

    Crisan, O; Crisan, A D [National Institute for Materials Physics PO Box MG-7 077125 Bucharest-Magurele (Romania); Skorvanek, I; Kovac, J, E-mail: ocrisan@yahoo.co [Institute of Experimental Physics, Slovak Academy of Sciences, 04001 Kosice (Slovakia)

    2009-01-01

    Fe /Fe{sub 3}O{sub 4} (magnetite) powders obtained by ball milling at room temperature, undergo an incomplete redox reaction with formation of FeO. This reaction is favoured due to the high energy developed during the milling and alloying. Concurrent effects of the milling, such as grain refinement down to the nanometric scale lead at the end of the milling processes to a mixed multiphased nanopowder, with a homogeneous dispersion of Fe and Fe oxide grains. Such ferromagnetic - antiferromagnetic systems are extensively studied due to their exchange bias properties, extremely useful in technological applications. We study the phase transformation that leads to a multiphased metal / oxide microstructure with an energydispersive in-situ X-ray diffraction experiment using the synchrotron radiation. This study allows direct collection of X-ray spectra after few minutes exposure, at selected temperatures, ranging between 20 deg. C and 1000 deg. C. Magnetic behavior has been studied for as-milled and annealed samples and the obtained magnetic parameters are correlated to the microstructure and phase composition at each stage of annealing. A significant exchange bias effect, related to FeO content, is observed for as-milled sample, the effect being less pronounced upon annealing the nanogranular powder.

  19. Estudo dos lactobacilos no biofilme dental

    OpenAIRE

    Clarissa Cavalcanti Fatturi Parolo

    2009-01-01

    Lactobacilos são um grupo de bactérias relacionadas com cárie dental. Há falta de estudos sobre a biologia populacional dos lactobacilos na cárie dental. O objetivo do estudo foi avaliar o efeito das modificações ambientais na composição, diversidade genética dos lactobacilos e Identificar a filogenia dos Lactobacillus paracasei isolados do biofilme. Lactobacilos foram isolados em um modelo de formação de biofilme in situ antes e depois de 28 dias de exposição à solução de sacarose 20%. As co...

  20. Por uma carta dos bens fundamentais

    OpenAIRE

    Luigi Ferrajoli

    2010-01-01

    Este artigo questiona a possibilidade de a estipulação dos direitos fundamentais, e suas obrigações e proibições correspondentes, ser suficiente para garantir adequadamente as necessidades e os interesses vitais, em especial aqueles de interesse coletivo. São bens fundamentais aqueles cujo acesso é garantido a todos e a cada um, visto que são objetos dos direitos fundamentais subtraídos à lógica do mercado. A garantia de novos bens como bens fundamentais exige uma decisão política civilizatór...

  1. Estrutura temporal dos tipos de xuro

    OpenAIRE

    Reboredo Nogueira, Juan Carlos

    2013-01-01

    Esta unidade didáctica forma parte do curso de Análise Económica dos Mercados Financeiros I que se imparte no primeiro cuadrimestre do Máster en Economía: Organización Industrial e Mercados Financeiros. Esta unidade ten como obxectivo analizar a estrutura temporal dos tipos de xuro, é dicir a relación existente entre os tipos de xuro a diferentes prazos. En particular, estudarase a curva cupón cero, a súa utilidade no proceso de valoración dos activos financeiros e os diferentes mé...

  2. Manual de buenas prácticas para el diseño, instalación y ejecución, mantenimiento y certificación de vías ferratas

    OpenAIRE

    Torres Leal, Juan Antonio

    2017-01-01

    El desarrollo de este trabajo de fin de grado tiene como objetivo principal la creación y publicación de un “Manual de Buenas Prácticas para el diseño, instalación y ejecución, mantenimiento y certificación de Vías Ferratas”. Este documento o guía técnica, que se encuentra en el Módulo 7 de este trabajo, se publicará de forma independiente a este TFG, siendo éste el motivo por el cual posee su propia estructura (índice de contenido, índice de tablas, índice de ilustraciones,…). Una vía fer...

  3. Dos personajes del arte narrativo de Cervantes

    OpenAIRE

    Navarro Durán, Rosa

    2017-01-01

    nuestra colaboradora rosa navarro trae a nuestras páginas dos personajes de las Novelas ejemplares de Cervantes. Las peripecias del licenciado Vidriera y de preciosa, la protagonista de 'La gitanilla', invitan a la reflexión. El primero enseña lecciones de vida con puntos de amargura. La segunda es la expresión de una persona de gran belleza humana que antepone siempre su libertad en todas sus acciones. Dos ejemplos del arte narrativo de Cervantes.

  4. Effects of Fe-deficient conditions on Fe uptake and utilization in P-efficient soybean.

    Science.gov (United States)

    Qiu, Wei; Dai, Jing; Wang, Nanqi; Guo, Xiaotong; Zhang, Xiaoli; Zuo, Yuanmei

    2017-03-01

    Phosphorus (P)-efficient soybean (Glycine max) plants absorb and utilize P with high efficiency. To investigate the effects of iron (Fe)-deficient conditions on the absorption and utilization of Fe in P-efficient soybean plants, two soybean cultivars with different P efficiency, the 03-3 (P-efficient variety) and Bd-2 (P-inefficient variety), were used in this study. The two soybean cultivars were grown in nutrient solution containing Fe concentrations of 0 (Fe0), 20 (Fe20), 40 (Fe40), or 80 (Fe80) μM for 7 days. The Fe reductase activity of roots was higher in 03-3 plants grown under the Fe0, Fe20, and Fe40 treatments than in Bd-2 plants and the total Fe uptake was greater in 03-3 plants under the Fe40 treatment. GmFRD3a was much more highly expressed in the stem of 03-3 than in that of Bd-2, and significantly more iron was transported to 03-3 plant shoots during Fe0 treatment. Chlorosis in young leaves caused by Fe deficiency under the Fe0 and Fe20 treatments was alleviated by increased Fe concentration in shoots. Increased levels of active Fe in young 03-3 leaves under Fe-deprivation conditions (Fe0) and maintenance of stable Fe concentrations in 03-3 shoots subjected to Fe20, Fe40, and Fe80 treatments suggested that the P-efficient 03-3 cultivar is also Fe-efficient. It is suggested that 03-3 soybean cultivar should be a good resource for application to farm field. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  5. Equilibrium Fe isotope fractionation between inorganic aqueous Fe(III) and the siderophore complex, Fe(III)-desferrioxamine B

    DEFF Research Database (Denmark)

    Dideriksen, Knud; Baker, Joel A.; Stipp, Susan Louise Svane

    2008-01-01

    In oxic oceans, most of the dissolved iron (Fe) exists as complexes with siderophore-like, strongly coordinating organic ligands. Thus, the isotope composition of the little amount of free inorganic Fe that is available for precipitation and preservation in the geological record may largely...... be controlled by isotope fractionation between the free and complexed iron.We have determined the equilibrium Fe isotope fractionation induced by organic ligand activity in experiments with solutions having co-existing inorganic Fe(III) species and siderophore complexes, Fedesferrioxamine B (at pH 2). The two...... differently complexed Fe(III) pools were separated by addition of Na2CO3, which led to immediate precipitation of the inorganic Fe without causing significant dissociation of Fe-desferrioxamine complexes. Experiments using enriched 57Fe tracer showed that isotopic equilibration between the 57Fe...

  6. BENEFÍCIOS DOS PARQUES URBANOS

    Directory of Open Access Journals (Sweden)

    Raphael Tavares Pacheco Martins

    2014-07-01

    Full Text Available Esta pesquisa teve como objetivo apresentar o tema e analisar os benefícios gerados pelos parques urbanos. Para a sua realização foi definido como zona de estudo a região norte do estado do Rio de Janeiro. Os outros objetivos foram a qualificação e a definição das funções do parque e a elucidação da sua contribuição para a melhoria da qualidade de vida. Além do lazer, outras funções socioambientais relevantes são desempenhadas pelos parques urbanos destacando-se a psicológica, a reconstrução da tranquilidade, a recomposição do temperamento, atenuante de ruídos e condicionador do microclima, impondo a sua inclusão no planejamento e nas políticas públicas das cidades. A pesquisa foi estruturada por um levantamento histórico e uma revisão bibliográfica. Um dos principais efeitos dos parques urbanos é a amenização climática, com contribuições positivas para o microclima local. No passar dos anos por conta dos grandes lucros as empresas privadas levaram o conjunto urbano para um crescimento desordenado e minimizando a função social dos parques urbanos, criando problemas sociais, esquecendo-se dos valores pessoais, históricos, culturais alem da dimensão sensorial e psicológica.

  7. Ligand-controlled Fe mobilization catalyzed by adsorbed Fe(II) on Fe(hydr)oxides

    Science.gov (United States)

    Kang, Kyounglim; Biswakarma, Jagannath; Borowski, Susan C.; Hug, Stephan J.; Hering, Janet G.; Schenkeveld, Walter D. C.; Kraemer, Stephan M.

    2017-04-01

    Dissolution of Fe(hydr)oxides is a key process in biological iron acquisition. Due to the low solubility of iron oxides in environments with a circumneutral pH, organisms may exude organic compounds catalyzing iron mobilization by reductive and ligand controlled dissolution mechanisms. Recently, we have shown synergistic effects between reductive dissolution and ligand-controlled dissolution that may operate in biological iron acquisition. The synergistic effects were observed in Fe mobilization from single goethite suspensions as well as in suspensions containing calcareous soil[1],[2]. However, how the redox reaction accelerates Fe(hydr)oxide dissolution by ligands is not studied intensively. In our study, we hypothesized that electron transfer to structural Fe(III) labilizes the Fe(hydr)oxide structure, and that this can accelerate ligand controlled dissolution. Systematical batch dissolution experiments were carried out under anoxic conditions at environmentally relevant pH values in which various Fe(hydr)oxides (goethite, hematite, lepidocrocite) interacted with two different types of ligand (desferrioxamine B (DFOB) and N,N'-Di(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid monohydrochloride (HBED)). Electron transfer to the structure was induced by adsorbing Fe(II) to the mineral surface at various Fe(II) concentrations. Our results show a distinct catalytic effect of adsorbed Fe(II) on ligand controlled dissolution, even at submicromolar Fe(II) concentrations. We observed the effect for a range of iron oxides, but it was strongest in lepidocrocite, most likely due to anisotropy in conductivity leading to higher near-surface concentration of reduced iron. Our results demonstrate that the catalytic effect of reductive processes on ligand controlled dissolution require a very low degree of reduction making this an efficient process for biological iron acquisition and a potentially important effect in natural iron cycling. References 1. Wang, Z. M

  8. Magnetostrictive GMR spin valves with composite FeGa/FeCo free layers

    National Research Council Canada - National Science Library

    Liu, Luping; Zhan, Qingfeng; Yang, Huali; Li, Huihui; Zhang, Shuanglan; Liu, Yiwei; Wang, Baomin; Tan, Xiaohua; Li, Run-Wei

    2016-01-01

    We have fabricated strain-sensitive spin valves on flexible substrates by utilizing the large magnetostrictive FeGa alloy to promote the strain sensitivity and the composite free layer of FeGa/FeCo...

  9. Del indicativo de la fe al imperativo de la ética

    Directory of Open Access Journals (Sweden)

    Tony Mifsud

    2012-01-01

    Full Text Available Después del Concilio Vaticano II, la reflexión de la Teología Moral abandona definitivamente un talante legalista a favor de un discurso enraizado en el horizonte bíblico de una respuesta humana a la llamada divina. Sin embargo, esta matriz bíblica no se entiende como una especie de "moral revelada", sino más bien como un ethos bíblico que da cuenta de una "realidad revelada" a la luz de la Buena Noticia y sus consecuencias en el estilo de vida de la comunidad de los discípulos. De esta manera, el indicativo de la fe se torna un imperativo ético.After the Second Vatican Council, the reflection of Moral Theology definitely abandons its legalistic spirit in favor of a discourse rooted in the biblical perspective of a human response to the divine call. However, this biblical matrix is not understood as a type of "revealed morality" but rather as a biblical ethos that accounts for a "revealed reality" in light of the Good News and its consequences on the lifestyle of the disciples' community. Thus, the indicative of faith becomes an ethical imperative.

  10. Study of the effects of metalloid elements (P, C, B) on Fe-based amorphous alloys by ab initio molecular dynamics simulations

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wenbiao; Li, Qiang, E-mail: qli@xju.edu.cn, E-mail: dhm@xju.edu.cn; Duan, Haiming, E-mail: qli@xju.edu.cn, E-mail: dhm@xju.edu.cn [School of Physics Science and Technology, Xinjiang University, Urumqi, Xinjiang 830046 (China)

    2015-03-14

    In order to understand the effects of the metalloid elements M (M: P, C, B) on the atomic structure, glass formation ability (GFA) and magnetic properties of Fe-based amorphous alloys, Fe{sub 80}P{sub 13}C{sub 7}, Fe{sub 80}P{sub 14}B{sub 6} and Fe{sub 80}B{sub 14}C{sub 6} amorphous alloys are chosen to study through first-principle simulations in the present work. The atomic structure characteristic of the three amorphous alloys is investigated through the pair distribution functions (PDFs) and Voronoi Polyhedra (VPs) analyses. The PDFs and VPs analyses suggest that the GFA of the three alloys dropped in the order of Fe{sub 80}P{sub 13}C{sub 7}, Fe{sub 80}P{sub 14}B{sub 6}, and Fe{sub 80}B{sub 14}C{sub 6}, which is well consistent with the experimental results. The density of state (DOS) of the three amorphous alloys is calculated to investigate their magnetic properties. Based on the DOS analysis, the average magnetic moment of Fe atom in Fe{sub 80}P{sub 13}C{sub 7} and Fe{sub 80}P{sub 14}B{sub 6} amorphous alloys can be estimated to be 1.71 μ{sub B} and 1.70 μ{sub B}, respectively, which are in acceptable agreement with the experimental results. However, the calculated average magnetic moment of Fe atom in Fe{sub 80}B{sub 14}C{sub 6} amorphous alloy is about 1.62 μ{sub B}, which is far less than the experimental result.

  11. Superoxide-mediated Fe(II) formation from organically complexed Fe(III) in coastal waters

    Science.gov (United States)

    Fujii, Manabu; Ito, Hiroaki; Rose, Andrew L.; Waite, T. David; Omura, Tatsuo

    2008-12-01

    Fe(III) complexed by organic ligands (Fe(III)L) is the primary form of dissolved Fe in marine and coastal environments. Superoxide, typically produced in biological and photochemical processes, is one of the reducing agents that contributes to transformation of Fe(III)L to bioavailable, free dissolved Fe(II) (Fe(II)'). In this work, the kinetics of superoxide-mediated Fe(II)' formation from Fe(III)L in a simulated coastal water system were investigated and a comprehensive kinetic model was developed using citrate and fulvic acid as exemplar Fe-binding ligands. To simulate a coastal environment in laboratory experiments, Fe(III)L samples with various ligand/Fe ratios were incubated for 5 min to 1 week in seawater medium. At each ratio and incubation time, the rate of superoxide-mediated Fe(II)' formation was determined in the presence of the strong Fe(II) binding ligand ferrozine by spectrophotometrically measuring the ferrous-ferrozine complex generated at a constant concentration of superoxide. The Fe(II)' formation rate generally decreased with incubation time, as Fe(III)L gradually dissociated to form less reactive Fe(III) oxyhydroxide. However, when the ligand/Fe ratio was sufficiently high, the dissociation of Fe(III)L (and subsequent Fe precipitation) was suppressed and Fe(II)' was formed at a higher rate. The rate of Fe(II)' produced during the experiment was explained by the kinetic model. The model confirmed that both the ligand/Fe ratio and incubation time have a significant effect on the pathway via which Fe(II)' is formed from Fe(III)-fulvic acid complexes.

  12. Almanak do Amigo dos Surdos Mudos

    Directory of Open Access Journals (Sweden)

    Solange Rocha

    2017-01-01

    Full Text Available A publicação apresentava, dentre outras coisas, aspectos cotidianos do Instituto como a presença em suas festas do Imperador Pedra II e outras autoridades do Império. No ano de 1888 foi lançado e distribuído gratuitamente, o Almanak do amigo dos surdos mudos. Seu conteúdo era voltado para as questões dos surdos e da surdez. Há registro de somente duas edições. A segunda edição é de 1889. Há um interessante registro da presença de um surdo francês de nome Marius Vicente que teria proposto uma premiação denominada - Senador Correia -, destinada ao surdo que mais se distinguisse no Instituto dos Surdos-Mudos do Rio de Janeiro. Consta que o prêmio foi conferido ao aluno Francisco José Gonçalves. Também trazia dados do recenseamento de surdos realizado em cada província com divisões dos grupos regionais entre homens, mulheres, cidadãos livres e escravos. Além de matérias sobre o processo educacional dos surdos, listas de surdos célebres nas artes, calendários, aforismos, bibliografias, fotografias e homenagens a figuras públicas importantes. 

  13. Strong 3D and 1D magnetism in hexagonal Fe-chalcogenides FeS and FeSe vs. weak magnetism in hexagonal FeTe.

    Science.gov (United States)

    Parker, David S

    2017-06-13

    We present a comparative theoretical study of the hexagonal forms of the Fe-chalcogenides FeS, FeSe and FeTe with their better known tetragonal forms. While the tetragonal forms exhibit only an incipient antiferromagnetism and experimentally show superconductivity when doped, the hexagonal forms of FeS and FeSe display a robust magnetism. We show that this strong magnetism arises from a van Hove singularity associated with the direct Fe-Fe c-axis chains in the generally more three-dimensional NiAs structure. We also find that hexagonal FeTe is much less magnetic than the other two hexagonal materials, so that unconventional magnetically-mediated superconductivity is possible, although a large T c value is unlikely.

  14. The influence of the cations Cu{sup +2}/Co{sup +2}/Nd{sup +3} at the ferrite Mi{sub 0,2}Y{sub 0,3}Zn{sub 0,5}Fe{sub 2}O{sub 4} at different temperatures; Estudo da influencia dos cations Cu{sup +2}/Co{sup +2}/Nd{sup +3} na ferrita Mi{sub 0,2}Y{sub 0,3}Zn{sub 0,5}Fe{sub 2}O{sub 4} em diferentes temperaturas

    Energy Technology Data Exchange (ETDEWEB)

    Lima, U.R., E-mail: ulisandra.lima@ifrn.edu.br [Instituto Federal de Educacao, Ciencia e Tecnologia do Rio Grande do Norte (IFRN), Sao Paulo do Potengi, RN (Brazil); Nasar, R.S.; Nasar, M.C.; Silva, J.E.M. da [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil). Programa de Pos-Grduacao em Quimica

    2016-07-01

    The work consisted of Ni{sub 0,2}Y{sub 0,3}Zn{sub 0,5}Fe{sub 2}O{sub 4} composition ferrites synthesis ranging copper ions (Cu{sup +2}), cobalt (Co{sup +2}) and neodymium (Nd{sup +3}) whose objective is to evaluate the particle size by the method citrate precursor. After synthesis, the samples were calcined at 350° C and subsequently sintered at 1000° for 3 hours, with controlled heating and cooling rate. The calcined materials were characterized by XRD and SEM showed that the method of the precursor citrate is an effective method. The X-ray diffraction spectra and refinement show good agreement between the experimental peaks and the theoretical spectrum. In Scanning Electron Microscopy (SEM), the samples to 350° C/3h, have dimensions in the micrometer order in all compositions. The average size of the crystals are consistent with the higher definition and intensity of peaks of X-rays, that is, there is high correlation with those obtained by refining method. (author)

  15. Effects of metal ions on the reactivity and corrosion electrochemistry of Fe/FeS nanoparticles.

    Science.gov (United States)

    Kim, Eun-Ju; Kim, Jae-Hwan; Chang, Yoon-Seok; Turcio-Ortega, David; Tratnyek, Paul G

    2014-04-01

    Nano-zerovalent iron (nZVI) formed under sulfidic conditions results in a biphasic material (Fe/FeS) that reduces trichloroethene (TCE) more rapidly than nZVI associated only with iron oxides (Fe/FeO). Exposing Fe/FeS to dissolved metals (Pd(2+), Cu(2+), Ni(2+), Co(2+), and Mn(2+)) results in their sequestration by coprecipitation as dopants into FeS and FeO and/or by electroless precipitation as zerovalent metals that are hydrogenation catalysts. Using TCE reduction rates to probe the effect of metal amendments on the reactivity of Fe/FeS, it was found that Mn(2+) and Cu(2+) decreased TCE reduction rates, while Pd(2+), Co(2+), and Ni(2+) increased them. Electrochemical characterization of metal-amended Fe/FeS showed that aging caused passivation by growth of FeO and FeS phases and poisoning of catalytic metal deposits by sulfide. Correlation of rate constants for TCE reduction (kobs) with electrochemical parameters (corrosion potentials and currents, Tafel slopes, and polarization resistance) and descriptors of hydrogen activation by metals (exchange current density for hydrogen reduction and enthalpy of solution into metals) showed the controlling process changed with aging. For fresh Fe/FeS, kobs was best described by the exchange current density for activation of hydrogen, whereas kobs for aged Fe/FeS correlated with electrochemical descriptors of electron transfer.

  16. QUE LA DICHA HERIDA SE LA DIO DE BUENA, SIN QUE INTERVINIESE TRAICIÓN ALGUNA...: EL ORDENAMIENTO DEL ESPACIO FRONTERIZO MAPUCHE, 1726-1760

    Directory of Open Access Journals (Sweden)

    LEONARDO LEÓN

    2011-10-01

    Full Text Available Nadie reconocía en él patria ni bandera. Cuando llegaba a los pagos de Quirihue, Rere, San Pedro, Tinguiririca, Puchacay o Maule, los inquilinos y mayordomos de las haciendas rehuían de su compañía porque leían en las cicatrices de su rostro, en los tatuajes de su cuerpo o en su hablar tosco y extraño, al hombre que vivía recorriendo caminos, huyendo de su propio nombre y de la justicia. Procreado en la violencia de un momento que nadie recordaba, su vida se inició en el mundo de los miserables, recogiendo las migajas con sabor a vino y cebolla, a charqui y queso añejo, para luego cazar furtivamente corderos, cabras y gallinas que degollaba con inusual calma para alimentar a su madre y a sus hermanastros; su juventud pasó entre muchas pendencias, grillos, cadenas, cepos y amores, aventuras y malones, para convertirse en hombre el día aciago en que por primera vez limpió de la hoja de su cuchillo la sangre de otro ser humano. Siempre llegaba y se iba en silencio, sin más nombre que sus apodos, que hablaban de otras muertes y de otras tierras, de asaltos, cuatrerismo y picardías; muchos se medían contra su sombra, otros se afanaban por ser sus conocidos y muy pocos podían llamarle amigo; bebedor incansable de aguardiente durante la vendimia y cantor alegre en las pulperías de extramuros, era un jugador empedernido de dados y naipes, de rayuelas y carreras ‘a la chilena’. Transitaba como sombra por fuertes, pagos y villas, puestos y vados, dejando tras de sí la extraña sensación de nunca haber pisado esa tierra. Sus historias en las noches lluviosas eran interminables, atrayendo sobre sí el halo de los hombres solitarios y andariegos que deslumbraban a las mujeres y niños, y que ejercían una fatal envidia entre los huasos e inquilinos. En su vida se entrecruzaban corregidores, comandantes y cabos de fuertes con la misma abundancia que lonkos, machis y caciques; hablaba con facilidad las dos lenguas, preparaba pócimas de

  17. AS DIMENSÕES DOS MODELOS MENTAIS DOS EMPREENDEDORES E SEUS IMPACTOS SOBRE O DESEMPENHO ORGANIZACIONAL

    Directory of Open Access Journals (Sweden)

    Deonir de Toni

    Full Text Available Este trabalho objetiva identificar as dimensões e variáveis básicas dos modelos mentais dos empreendedores, bem como os seus impactos sobre o desempenho de suas empresas. Para isso, foi realizada uma pesquisa qualitativa com seis empreendedores, e uma pesquisa quantitativa com 113 empresas do setor metalomecânico na Serra Gaúcha. Dentre as contribuições deste trabalho, destaca-se, primeiramente a proposição de um modelo teórico no qual se identificam sete dimensões dos modelos mentais dos empreendedores relacionadas ao desempenho organizacional. Uma segunda contribuição é a proposição de uma escala para a mensuração dos modelos mentais dos dirigentes das empresas. Os resultados da pesquisa confirmam que a escala proposta se ajustou bem às dimensões identificadas na revisão da literatura e que dentre as sete dimensões apresentadas, as que estão relacionadas ao conhecimento, ao relacionamento, à missão e à estratégia, à criatividade e à vocação apresentaram um impacto significativo sobre o desempenho das organizações analisadas. Verificou-se que 27,5% do poder explicativo do desempenho organizacional pode estar associado às dimensões formadoras dos modelos mentais dos empreendedores.

  18. Conocimientos sobre vivienda saludable en dos barrios de Bucaramanga, Colombia - 2012

    Directory of Open Access Journals (Sweden)

    Johana Gutiérrez Zehr

    2014-08-01

    Full Text Available Objetivo: Determinar el conocimiento sobre vivienda saludable en dos barrios de Bucaramanga. Metodología: Estudio descriptivo transversal realizado en 100 padres o acudientes de niños y niñas adscritos a los hogares del Instituto de Bienestar Familiar de los barrios Estoraques y Girardot. Las variables recolectadas fueron sociodemográficas y conocimientos sobre vivienda saludable mediante un cuestionario autodiligenciado creado por los autores. En el análisis estadístico, se aplicaron medidas de tendencia central y de dispersión para las variables cuantitativas o frecuencia absolutas y relativas para las variables cualitativas. Para todo el análisis se consideró un nivel de significancia alpha=0.05. Resultados: Las preguntas que fueron respondidas correctamente en menor proporción fueron: la relacionada con acciones preventivas para evitar accidentes en los niños (Un hogar sin peligros implica tener buenas acciones, de las siguientes acciones cual es la más adecuada con un 7%; dos relacionadas con el dengue, la primera (de las siguientes acciones para evitar el dengue cual no es la correcta con un 8% y la segunda (de las siguientes cual no es una opción para protegernos de la picadura de mosquitos con un 35%; En una escala de 0 a 12 el promedio fue de 6,7± 1,8 y no se encontraron diferencias estadísticamente significativas por edad, sexo y educación previa. Conclusión: Es necesario la realización de programas que permitan aumentar y consolidar conocimientos sobre vivienda saludable, habilitación, adaptación, manejo, uso y mantenimiento de la vivienda y su entorno con seguridad y calidad, al igual que promover una orientación hacia prácticas protectoras para la salud, la promoción de la misma y la prevención de la enfermedades y de accidentes domésticos , al desestimular las actitudes y hábitos que pueden constituir riesgo para la familia y su hogar.

  19. Structure and magnetic properties of Fe/Fe oxide clusters

    Energy Technology Data Exchange (ETDEWEB)

    Crisan, O., E-mail: ocrisan@yahoo.com; Haeften, K. von [University of Leicester, Condensed Matter Physics CMP (United Kingdom); Ellis, A. M. [University of Leicester, Department of Chemistry (United Kingdom); Binns, C. [University of Leicester, Condensed Matter Physics CMP (United Kingdom)

    2008-12-15

    Fe clusters have been synthesised in ultra-high-vacuum chamber using a gas-stabilized cluster aggregation method that ensures good control of the cluster size and naturally oxidized in order to obtain Fe/Fe oxide core-shell nanoparticles. The morphology of an individual nanoparticle, as revealed by transmission electron microscopy, consists of a Fe core of an average diameter of 4.4 nm surrounded by an oxide shell of uniform thickness of about 1.2 nm in average. The nanoparticles may be assimilated with a ferro-/antiferromagnetic (FM/AF) system. The morpho-structural features have been correlated with magnetic measurements on the core-shell nanoparticles. A significant exchange bias effect has been measured, when the sample was field-cooled under an applied field of 3 T. As the morphology of core-shell nanoclusters is much more complicated than in FM/AF bilayers of regular thickness due to the particular geometry of the coronal AF layer, the shape and surface anisotropy have to be taken into account for a correct interpretation of the magnetic data.

  20. Factores socio-económicos asociados a la percepción de situación socioeconómica entre adultos mayores de dos países latinoamericanos

    Science.gov (United States)

    Brenes-Camacho, Gilbert

    2014-01-01

    El objetivo principal del artículo es estudiar la asociación entre la percepción subjetiva sobre la situación económica propia y una serie de medidas objetivas de bienestar socioeconómico –fuentes de ingresos, tenencia de vivienda, nivel educativo y transferencias familiares informales de dinero- entre adultos mayores de dos países Latinoamericanos: México y Costa Rica. Los datos se obtienen de las primeras rondas de dos encuestas sobre envejecimiento: CRELES para Costa Rica y ENASEM para México. La variable dependiente más importante se obtiene de las respuestas a las pregunta “¿Cómo califica su situación económica actual?” en Costa Rica y “¿Diría usted que su situación económica es…?” en México. Para ambas encuestas, las respuestas se codificaron en forma binaria; el código 0 representa las categorías Excelente, Muy buena y Buena, y el código 1 representa a las categorías Regular y Mala. Se encontró que el ingreso por jubilación es un importante determinante de la percepción de bienestar en ambos países. En Costa Rica, el ingreso del cónyuge y la tenencia de vivienda son importantes predictores de la percepción de bienestar, mientras que en México, los ingresos por transferencias están fuertemente asociados con dicha percepción. PMID:25360057

  1. Solubilidade e disponibilidade dos micronutrientes em fertilizantes

    OpenAIRE

    F. Vale; J.C. Alcarde

    1999-01-01

    A legislação brasileira exige que os micronutrientes nos fertilizantes sejam garantidos pelo teor total presente. Isto abre um precedente para a utilização de produtos não considerados como fontes de micronutrientes na fabricação dos fertilizantes. Todavia, a eficiência agronômica desses produtos é ainda duvidosa. Objetivou-se realizar um trabalho para caracterizar a solubilidade e a disponibilidade dos micronutrientes em trinta fertilizantes comerciais, por meio do uso de cinco extratores qu...

  2. Magnetic Properties of Tetragonally Distorted Fe3Pt and the Hybrid Structure Fe3Pt/Fe

    Science.gov (United States)

    Sakuma, Akimasa

    1995-11-01

    To investigate the magnetic performance of a hybrid structure oftransition metals, we consider the Fe3Pt/Fe system and examine theeffects both of the tetragonal distortion of L12 type Fe3Pt andthe hybridization with bcc-Fe on the magnetic properties, usingLMTO-ASA method in the framework of LSD. The magnetic moment ofFe3Pthas a maximum stationary value of 8.85 µ B/ cell atc/a=1/\\sqrt{2}. The hypothetical struc-ture of Fe20Pt4 is supposed by combining Fe3Pt of c/a=1/\\sqrt{2} and bcc-Fe lattice. It is predicted that the magnetizationreaches 2.27 T with the magnetic anisotropy constant of 11×105 J/ m3. With using the coherent rotation model formagnetization reversal process, we get maximum energy product(BH) max=10.2 MJ/ m3.

  3. Anomalous superconducting spin-valve effect in NbN/FeN/Cu/FeN/FeMn multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Tae Jong; Kim, Dong Ho [Yeungnam University, Gyeongsan (Korea, Republic of)

    2017-09-15

    We have studied magnetic and transport properties of NbN/FeN/Cu/FeN/FeMn spin-valve structure. In-plane magnetic moment exhibited typical hysteresis loops of spin valves in the normal state of NbN film at 20 K. On the other hand, the magnetic hysteresis loop in the superconducting state exhibited more complex behavior in which exchange bias provided by antiferrmagnetic FeMn layer to adjacent FeN layer was disturbed by superconductivity. Because of this, the ideal superconducting spin-valve effect was not detected. Instead the stray field originated from unsaturated magnetic states dominated the transport properties of NbN/FeN/Cu/FeN/FeMn multilayer.

  4. Microestructura y magnetismo en óxidos de Cu y Fe

    OpenAIRE

    Borzi, Rodolfo Alberto

    2001-01-01

    Este trabajo de Tesis propone un estudio experimental sobre las propiedades magnéticas de óxidos de Cu y Fe cuando se los somete a tratamientos que modifican su microestructura. Principalmente son mezclas de CuO y α-Fe2O3 -dos óxidos antiferromagnéticos-y de ferrita CuFe2O4, todos materiales con complejas propiedades magnéticas sobre los que se ha desarrollado una intensa actividad de investigación en los últimos años. La combinación de difracción de rayos x, microscopía electrónica de transm...

  5. Thermodynamics of Fe(II)Fe(III) oxide systems I. Hydrothermal Fe3O4

    Science.gov (United States)

    Bartel, J.J.; Westrum, E.F.; Haas, J.L.

    1976-01-01

    The heat capacity of a hydrothermally-prepared polycrystalline sample of Fe3O4 was measured from 53 to 350 K, primarily to study the thermophysics of the Verwey transitions. Although the bifurcation of the transition was confirmed, the sample was found to contain traces of manganese. The observed transition temperatures of 117.0 and 123.0 K are 3.7 and 4.2 K higher respectively than those found in pure Fe3O4. Ancillary analytical results are consistent and indicate a stoichiometry of Mn0.008Fe2.992O4 for this material. Characteristics in the transition region are ascribed to dopant effects. ?? 1976.

  6. Teores de Fe, Mn, Zn, Cu, Ni E Co em solos de referência de Pernambuco

    Directory of Open Access Journals (Sweden)

    Caroline Miranda Biondi

    2011-06-01

    Full Text Available Metais pesados formam um grupo de elementos com particularidades relevantes e de ocorrência natural no ambiente, como elementos acessórios na constituição de rochas. Esses elementos, apesar de associados à toxidez, exigem tratamento diferenciado em relação aos xenobióticos, uma vez que diversos metais possuem essencialidade (Fe, Mn, Cu, Zn e Ni e benefício (Co comprovados para as plantas. Nesse contexto, o objetivo deste trabalho foi determinar os teores naturais dos metais Fe, Mn, Zn, Ni, Cu e Co nos solos de referência de Pernambuco. Foram coletadas amostras de solo nas três regiões fisiográficas (Zona da Mata, Agreste e Sertão, dos dois primeiros horizontes dos 35 solos de referência do Estado de Pernambuco. A digestão das amostras baseou-se no método 3051A (USEPA, 1998, e a determinação foi efetuada em ICP-OES. Correlações significativas foram estabelecidas entre os metais e entre estes e a fração argila do solo, em ambos os horizontes, indicando a associação comum da maioria dos metais com solos mais argilosos. A maioria dos solos apresentou teores de Fe, Mn, Zn, Cu, Ni e Co menores que os de solos de outras regiões do País, com litologia mais máfica, o que corrobora o fato de que os teores desses elementos são mais diretamente relacionados aos minerais Fe-magnesianos. Os resultados indicam baixo potencial dos solos de Pernambuco em liberar Cu, Co e Ni para plantas, enquanto deficiências de Zn, Fe e Mn são menos prováveis. Os teores naturais de Fe, Mn, Zn, Cu, Ni e Co determinados podem ser utilizados como base para definição dos Valores de Referência de Qualidade para os solos de Pernambuco, de acordo com o preconizado pela legislação nacional.

  7. Spin structure of exchange biased heterostructures. Fe/MnF{sub 2} and Fe/FeF{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, B.

    2006-12-18

    In this work, the {sup 57}Fe probe layer technique is used in order to investigate the depth- and temperature-dependent Fe-layer spin structure of exchange biased Fe/MnF{sub 2} and Fe/FeF{sub 2} (pseudo-twinned) antiferromagnetic (AFM) systems by conversion electron Moessbauer spectroscopy (CEMS) and nuclear resonant scattering (NRS) of synchrotron radiation. Two kinds of samples with a 10 A {sup 57}Fe probe layer directly at or 35 A away from the interface, labeled as interface and center sample, respectively, were studied in this work. The results obtained by CEMS for Fe/MnF{sub 2} suggests that, at 80 K, i.e., above T{sub N}=67 K of MnF{sub 2}, the remanent state Fe-layer spin structure of the two studied samples are slightly different due to their different microstructure. In the temperature range from 300 K to 80 K, the Fe-layer spin structure does not change just by zero-field cooling the sample in remanence. For Fe/FeF{sub 2}, a continuous non-monotonic change of the remanent-state Fe spin structure was observed by cooling from 300 K to 18 K. NRS of synchrotron radiation was used to investigate the temperature- and depth-dependent Fe-layer spin structure during magnetization reversal in pseudo-twinned Fe/MnF{sub 2}. A depthdependent Fe spin structure in an applied magnetic field (applied along the bisector of the twin domains) was observed at 10 K, where the Fe spins closer to the interface are not aligned along the field direction. The depth-dependence disappears at 150 K. (orig.)

  8. Structural and magnetic properties of NdFeB and NdFeB/Fe films with Mo addition

    Energy Technology Data Exchange (ETDEWEB)

    Urse, M; Grigoras, M; Lupu, N; Chiriac, H, E-mail: urse@phys-iasi.ro [National Institute of R and D for Technical Physics, 47 Mangeron Blvd., 700050 Iasi (Romania)

    2011-07-06

    The influence of the Mo addition on the microstructure and magnetic properties of Nd-Fe-B and Nd-Fe-B/Fe films was studied. The coercivity is a key parameter in the control of technical performances of Nd-Fe-B films. A small amount of about 1 at.% Mo can enhance the coercivity of Nd-Fe-B film by controlling the growth of soft and hard magnetic grains. A coercivity of 22.1 kOe, a remanence ratio, M{sub r}/M{sub s}, of 0.83 and a maximum energy product of 8 MGOe were obtained for Ta/[NdFeBMo(1at.%)(540nm)/Ta films annealed at 650{sup 0}C for 20 minutes due to Mo precipitates formed at the Nd{sub 2}Fe{sub 14}B phase boundaries which prevent the nucleation and expansion of the magnetic domains. Simultaneous use of Mo as addition and the stratification of Nd-Fe-B-Mo films using Fe as spacer layer are important tools for the improvement of the hard magnetic properties of Nd-Fe-B films. The Ta/[NdFeBMo(1at.%)(180nm)/Fe(1nm)]x3/Ta multilayer film annealed at 620{sup 0}C exhibits an increase in the coercivity from 12.1 kOe to 22.8 kOe, in the remanence ratio from 0.77 to 0.80, and in the maximum energy product from 4.5 to 7.1 MGOe in comparison with Ta/Nd-Fe-B/Ta film. As compared to Ta/Nd-Fe-B/Ta film, the Ta/[NdFeBMo(1at.%)(180nm)/Fe(1nm)]x3/Ta film presents a decrease in the crystallization temperature of about 30{sup 0}C.

  9. Size dependent structural and magnetic properties of FeO-Fe3O4 nanoparticles

    Science.gov (United States)

    Lak, Aidin; Kraken, Mathias; Ludwig, Frank; Kornowski, Andreas; Eberbeck, Dietmar; Sievers, Sibylle; Litterst, F. J.; Weller, Horst; Schilling, Meinhard

    2013-11-01

    The magnetic properties of monodisperse FeO-Fe3O4 nanoparticles with different mean sizes and volume fractions of FeO synthesized via decomposition of iron oleate were correlated to their crystallographic and phase compositional features by exploiting high resolution transmission electron microscopy, X-ray diffraction, Mössbauer spectroscopy and field and zero field cooled magnetization measurements. A model describing the phase transformation from a pure Fe3O4 phase to a mixture of Fe3O4, FeO and interfacial FeO-Fe3O4 phases as the particle size increases was established. The reduced magnetic moment in FeO-Fe3O4 nanoparticles was attributed to the presence of differently oriented Fe3O4 crystalline domains in the outer layers and paramagnetic FeO phase. The exchange bias energy, dominating magnetization reversal mechanism and superparamagnetic blocking temperature in FeO-Fe3O4 nanoparticles depend strongly on the relative volume fractions of FeO and the interfacial phase.The magnetic properties of monodisperse FeO-Fe3O4 nanoparticles with different mean sizes and volume fractions of FeO synthesized via decomposition of iron oleate were correlated to their crystallographic and phase compositional features by exploiting high resolution transmission electron microscopy, X-ray diffraction, Mössbauer spectroscopy and field and zero field cooled magnetization measurements. A model describing the phase transformation from a pure Fe3O4 phase to a mixture of Fe3O4, FeO and interfacial FeO-Fe3O4 phases as the particle size increases was established. The reduced magnetic moment in FeO-Fe3O4 nanoparticles was attributed to the presence of differently oriented Fe3O4 crystalline domains in the outer layers and paramagnetic FeO phase. The exchange bias energy, dominating magnetization reversal mechanism and superparamagnetic blocking temperature in FeO-Fe3O4 nanoparticles depend strongly on the relative volume fractions of FeO and the interfacial phase. Electronic supplementary

  10. Vibrational thermodynamics of Fe90Zr7B3 nanocrystalline alloy from nuclear inelastic scattering

    DEFF Research Database (Denmark)

    Stankov, S.; Miglierini, M.; Chumakov, A. I.

    2010-01-01

    Recently we determined the iron-partial density of vibrational states (DOS) of nanocrystalline Fe(90)Zr(7)B(3) (Nanoperm), synthesized by crystallization of an amorphous precursor, for various stages of nanocrystallization separating the DOS of the nanograins from that of the interfaces [S. Stankov......, Y. Z. Yue, M. Miglierini, B. Sepiol, I. Sergueev, A. I. Chumakov, L. Hu, P. Svec, and R. Ruffer, Phys. Rev. Lett. 100, 235503 (2008)]. Here we present quantitative analysis of the evolution of various thermoelastic properties calculated from DOS such as mean-force constant, mean atomic displacement......, vibrational entropy, and lattice specific heat as the material transforms from amorphous, through nanocrystalline, to fully crystallized state. The reported results shed new light on the previously observed anomalies in the vibrational thermodynamics of nanocrystalline materials....

  11. Understanding FE Mergers. Research Report

    Science.gov (United States)

    Calvert, Natasha

    2009-01-01

    This report presents research findings and discussion to help develop an understanding of what gives rise to mergers and, when they do happen, what makes them work. The research has focused on merger activity between further education (FE) colleges since incorporation in 1993. Mergers are highly contextual, and part of ensuring success is…

  12. Modeling equilibrium Fe isotope fractionation

    Science.gov (United States)

    Anbar, A.; Jarzecki, A.; Spiro, T.

    2003-04-01

    Research into the stable isotope biogeochemistry of Fe and other transition metals has been driven primarily by analytical innovations which have revealed significant isotope effects in nature and the laboratory. Further development of these new isotope systems requires complementary theoretical research to guide analytical efforts. The results of the first such studies show some discrepancies with experiments. For example, Johnson et al. (2002) report an experimentally-determined 56Fe/54Fe equilibrium fractionation factor between Fe(II) and Fe(III) aquo complexes of ˜1.0025. This effect is ˜50% smaller than predicted theoretically by Schauble et al. (2001). It is important to resolve such discrepancies. Equilibrium isotope fractionation factors can be predicted from vibrational spectroscopic data of isotopically-substituted complexes, or from theoretical predictions of some or all of these frequencies obtained using force field models. The pioneering work of Schauble et al. (2001) utilized a modified Urey-Bradley force field (MUBFF) model. This approach is limiting in at least three ways: First, it is not ab initio, requiring as input some measured vibrational frequencies. Such data are not always available, or may have significant uncertainties. Second, the MUBFF does not include potentially important effects of solvent interaction. Third, because it makes certain assumptions about molecular symmetry, the MUBFF-based approach is not able to model the spectra of mixed-ligand complexes. To address these limitations, we are evaluating the use of density functional theory (DFT) as an ab initio method to predict vibrational frequencies of isotopically-substituted complexes and, hence, equilibrium fractionation factors. In a preliminary examination of the frequency shift upon isotope substitution of the bending and asymmetric stretching modes of the tetrahedral FeCl_42- complex, we find substantial differences between MUBFF and DFT predictions. Results for other Fe

  13. Consistentie met MS-DOS software

    NARCIS (Netherlands)

    Olsthoorn TN

    1988-01-01

    Zonder de keuze van een zekere standaard-lijn ten aanzien van de software die men zelf gebruikt, kan nauwelijks efficient met een computer worden gewerkt. Onder UNIX en op de Macintosh is het gebruik van programma's en de uitwisseling van gegevens daartussen gestandaardiseerd. Onder MS-DOS

  14. A Teoria dos Conjuntos de Cantor

    Directory of Open Access Journals (Sweden)

    Antônio Acra Freiria

    1992-07-01

    Full Text Available No final dos anos 50 e começo doe anos 60, houve uma reformulação significativa da Matemática no Brasil. Sob a bandeira do modernismo, seus defensores buscaram inovações no ensino da Matemática. Dessa forma, os reformistas se concentraram essencialmente na linguagem abusiva e no formalismo da Teoria dos Conjuntos, o que trouxe mais danos do que benefícios do ensino da Matemática de 1º e 2ºgraus. A linguagem formal da Teoria dos Conjuntos é porém sua parte menos importante. A teoria criada por Cantor tão logo revelou-se como o fundamento de toda a Matemática, possibilitando o desenvolvimento de novas disciplinas, como a Topologia, a Algebra Abstrata, a Teoria da Medida e Integração, a Teoria da Probabilidade e a Análise Funcional. O objetivo deste trabalho é um relato sucinto de como surgiu essa teoria, apresentando o "Conjunto de Cantor" como um dos mais ricos exemplos de "Conjunto perfeito" encontrados na literatura matemática.

  15. Teores de Fe, Mn, Zn, Cu, Ni E Co em solos de referência de Pernambuco Concentrations of Fe, Mn, Zn, Cu, Ni and Co in benchmark soils of Pernambuco, Brazil

    Directory of Open Access Journals (Sweden)

    Caroline Miranda Biondi

    2011-06-01

    Full Text Available Metais pesados formam um grupo de elementos com particularidades relevantes e de ocorrência natural no ambiente, como elementos acessórios na constituição de rochas. Esses elementos, apesar de associados à toxidez, exigem tratamento diferenciado em relação aos xenobióticos, uma vez que diversos metais possuem essencialidade (Fe, Mn, Cu, Zn e Ni e benefício (Co comprovados para as plantas. Nesse contexto, o objetivo deste trabalho foi determinar os teores naturais dos metais Fe, Mn, Zn, Ni, Cu e Co nos solos de referência de Pernambuco. Foram coletadas amostras de solo nas três regiões fisiográficas (Zona da Mata, Agreste e Sertão, dos dois primeiros horizontes dos 35 solos de referência do Estado de Pernambuco. A digestão das amostras baseou-se no método 3051A (USEPA, 1998, e a determinação foi efetuada em ICP-OES. Correlações significativas foram estabelecidas entre os metais e entre estes e a fração argila do solo, em ambos os horizontes, indicando a associação comum da maioria dos metais com solos mais argilosos. A maioria dos solos apresentou teores de Fe, Mn, Zn, Cu, Ni e Co menores que os de solos de outras regiões do País, com litologia mais máfica, o que corrobora o fato de que os teores desses elementos são mais diretamente relacionados aos minerais Fe-magnesianos. Os resultados indicam baixo potencial dos solos de Pernambuco em liberar Cu, Co e Ni para plantas, enquanto deficiências de Zn, Fe e Mn são menos prováveis. Os teores naturais de Fe, Mn, Zn, Cu, Ni e Co determinados podem ser utilizados como base para definição dos Valores de Referência de Qualidade para os solos de Pernambuco, de acordo com o preconizado pela legislação nacional.Heavy metals are a group of elements with specific features and natural occurrence in the environment, representing an accessory in the formation of rocks. These elements, although associated with toxicity, must be treated different from xenobiotics, since many

  16. Solubilidade e disponibilidade dos micronutrientes em fertilizantes

    Directory of Open Access Journals (Sweden)

    F. Vale

    1999-06-01

    Full Text Available A legislação brasileira exige que os micronutrientes nos fertilizantes sejam garantidos pelo teor total presente. Isto abre um precedente para a utilização de produtos não considerados como fontes de micronutrientes na fabricação dos fertilizantes. Todavia, a eficiência agronômica desses produtos é ainda duvidosa. Objetivou-se realizar um trabalho para caracterizar a solubilidade e a disponibilidade dos micronutrientes em trinta fertilizantes comerciais, por meio do uso de cinco extratores químicos: a água e soluções de ácido cítrico a 2%, de citrato neutro de amônio na diluição 1 + 9, de DTPA 0,005 mol L-1 e de EDTA 0,005 mol L-1. Os resultados mostraram a baixa solubilidade dos micronutrientes metálicos (cobre, ferro, manganês e zinco dos fertilizantes tipo "fritas". O ácido cítrico a 2% mostrou-se promissor na caracterização da disponibilidade de cobre, manganês e zinco para as plantas. Para o ferro não houve uma definição entre os extratores estudados. O boro teve boa solubilidade, tanto nos fertilizantes solúveis, como nos insolúveis em água, e a garantia pelo teor total mostrou-se bom indicativo da disponibilidade do elemento. Para o molibdênio a solubilidade foi maior para os fertilizantes com baixo teor do elemento. A garantia dos micronutrientes catiônicos pelo teor total, conforme exige a legislação, não indicou a sua real disponibilidade nos fertilizantes comerciais, mostrando a necessidade de uma definição de extratores para esse fim.

  17. Guía de buenas prácticas de seguridad informática en el tratamiento de datos de salud para el personal sanitario en atención primaria

    Directory of Open Access Journals (Sweden)

    Ana Sánchez-Henarejos

    2014-04-01

    Full Text Available Con la introducción de la historia clínica digital surge la necesidad de reforzar la seguridad de los datos personales de salud para garantizar su privacidad. A pesar de la gran cantidad de medidas de seguridad técnicas y de recomendaciones existentes para el ámbito sanitario, hay un aumento en las violaciones de la privacidad de los datos personales de los pacientes en centros sanitarios, en muchos casos como consecuencia de errores o descuidos de los profesionales sanitarios. En este trabajo se presenta una guía de buenas prácticas de seguridad informática en la manipulación de los datos personales de salud por parte del personal sanitario, elaborada a partir de recomendaciones, normativa y estándares nacionales e internacionales. El material presentado en este trabajo puede emplearse tanto en la formación como en auditorías de seguridad informática a trabajadores de los centros de atención primaria.

  18. El Laboratorio de Teatro Campesino e Indígena y la construcción de la vida buena en Ticopó, Yucatán, México

    Directory of Open Access Journals (Sweden)

    Carmen Castillo Rocha

    Full Text Available Resumen En el contexto del campo de la Comunicación para el desarrollo y el cambio social, el presente artículo tiene el objetivo de explorar la relación entre teatro y desarrollo en el caso del "Laboratorio de Teatro Campesino e Indígena" (2004-2006 con base en una investigación Ex post facto realizada mediante entrevistas focales a habitantes de las localidades mayas de Ticopó y Canicab enYucatán, México. Con este propósito se hace un recorrido por algunas perspectivas teóricas haciendo énfasis en el edu-entretenimiento para llegar a la propuesta de Augusto Boal y a experiencias de teatro no-pedagógico en América Latina. Se describe la práctica teatral de María Alicia Martínez Medrano y la huella que dejó en sus participantes ocho años después de haber concluido la representación de la obra Siete momentos en la vida de los mayas. Se concluye que el ejercicio escénico realizado en Ticopó contribuyó a construir lazos afectivos, momentos recreativos, contactos interculturales, viajes, convivencia familiar, autoestima cultural, imagen y pensamiento sensible hacia la edificación de una vida buena.

  19. Buenas prácticas de aplicación en cultivos planos extensivos: Distancias a zonas urbanas. Criterios y soluciones Good practices of application on extensive flat crops: Distances to urban areas. Criterions and salutions

    Directory of Open Access Journals (Sweden)

    Alberto Etiennot

    2010-12-01

    Full Text Available El presente trabajo engloba todos los conocimientos actuales y disponibles técnico científicos con respecto a las aplicaciones de agroquímicos en proximidad a las zonas periurbanas y urbanas, considerando los diversos factores que contribuyen a un eficiente y eficaz trabajo agrícola, sugiriendo prácticas y estableciendo distancias a favor de la seguridad de la población y de las Buenas Prácticas Agrícolas. Concluyendo en un cuadro de sugerencias basado en la toxicidad aguda de los agroquímicos.The present document includes the whole current and available scientific technical knowledge regarding to the agrichemical applications next to the rural-urban and urban zones, considering the several factors that contribute to an efficient and effective agricultural work, suggesting practices and establishing distances in favour of the population's security and of the Good Agricultural Practices. Concluding in a picture of suggestions based on the acute toxicity of the agrichemicals.

  20. Deontología profesional en Información Médica en la industria farmacéutica: en el camino hacia un código español de buenas prácticas

    Directory of Open Access Journals (Sweden)

    Rojo Abril, Mónica

    2016-07-01

    Full Text Available Introducción: En España, la Industria Farmacéutica es uno de los principales proveedores de Información Médica dentro del ámbito de la salud. En su compromiso con el servicio que proporcionan, los Técnicos de Información Médica (TIM echan en falta un marco deontológico que guíe su actividad y garantice la calidad, la equidad y el equilibrio de la información que proporcionan a los profesionales sanitarios. Objetivo: En su camino hacia un código español de buenas prácticas, el Grupo de Trabajo de Información Médica de la Asociación de Medicina de la Industria Farmacéutica (AMIFE quiere presentar a la comunidad profesional el marco deontológico en que se manifiesta su reflexión ética, así como establecer los puntos de partida sobre los que afronta la elaboración de un texto accesible a todos los profesionales del sector y a las empresas que proporcionan y respaldan sus actividades.

  1. Atom exchange between aqueous Fe(II) and structural Fe in clay minerals.

    Science.gov (United States)

    Neumann, Anke; Wu, Lingling; Li, Weiqiang; Beard, Brian L; Johnson, Clark M; Rosso, Kevin M; Frierdich, Andrew J; Scherer, Michelle M

    2015-03-03

    Due to their stability toward reductive dissolution, Fe-bearing clay minerals are viewed as a renewable source of Fe redox activity in diverse environments. Recent findings of interfacial electron transfer between aqueous Fe(II) and structural Fe in clay minerals and electron conduction in octahedral sheets of nontronite, however, raise the question whether Fe interaction with clay minerals is more dynamic than previously thought. Here, we use an enriched isotope tracer approach to simultaneously trace Fe atom movement from the aqueous phase to the solid ((57)Fe) and from the solid into the aqueous phase ((56)Fe). Over 6 months, we observed a significant decrease in aqueous (57)Fe isotope fraction, with a fast initial decrease which slowed after 3 days and stabilized after about 50 days. For the aqueous (56)Fe isotope fraction, we observed a similar but opposite trend, indicating that Fe atom movement had occurred in both directions: from the aqueous phase into the solid and from the solid into aqueous phase. We calculated that 5-20% of structural Fe in clay minerals NAu-1, NAu-2, and SWa-1 exchanged with aqueous Fe(II), which significantly exceeds the Fe atom layer exposed directly to solution. Calculations based on electron-hopping rates in nontronite suggest that the bulk conduction mechanism previously demonstrated for hematite1 and suggested as an explanation for the significant Fe atom exchange observed in goethite2 may be a plausible mechanism for Fe atom exchange in Fe-bearing clay minerals. Our finding of 5-20% Fe atom exchange in clay minerals indicates that we need to rethink how Fe mobility affects the macroscopic properties of Fe-bearing phyllosilicates and its role in Fe biogeochemical cycling, as well as its use in a variety of engineered applications, such as landfill liners and nuclear repositories.

  2. Laser alloyed Al-Ni-Fe coatings

    CSIR Research Space (South Africa)

    Pityana, SL

    2008-10-01

    Full Text Available The aim of this work was to produce crack-free thin surface layers consisting of binary (Al-Ni, Al-Fe) and ternary (Al-Ni-Fe) intermetallic phases by means of a high power laser beam. The laser surface alloying was carried out by melting Fe and Ni...

  3. Biogeochemical speciation of Fe in ocean water

    NARCIS (Netherlands)

    Hiemstra, T.; Riemsdijk, van W.H.

    2006-01-01

    The biogeochemical speciation of Fe in seawater has been evaluated using the consistent Non-Ideal Competitive Adsorption model (NICA¿Donnan model). Two types of data sets were used, i.e. Fe-hydroxide solubility data and competitive ligand equilibration/cathodic stripping voltammetry (CLE/CSV) Fe

  4. Growth of superconducting FeSe films

    Science.gov (United States)

    Naito, Michio; Agatsuma, Shinya; Ueda, Shinya

    2009-03-01

    The recently discovered Fe arsenide and chalcogenide superconductors have provided the superconducting community with a great surprise that Fe-based compounds are not ferromagnetic but superconducting with high Tc. The superconducting Fe arsenides and chalcogenides are also interested from the viewpoint of superconducting electronics. One can see good lattice compatibility between the superconducting Fe family and the existing III-V and II-VI semiconducting family (GaAs, ZnSe). All-epitaxial super-semiconductor multilayer structures may be ideal for superconducting electronics and spintronics. Toward this goal, we have attempted to grow epitaxial thin films of the superconducting Fe family. Of this family, tetragonal α-FeSe seems to be the easiest to grow thin films. We employed two approaches for FeSe film growth: post-annealing and MBE growth. In the post-annealing, precursor films of Fe are annealed at 500 - 600 ^oC with Se vapor in an evacuated quartz tube. Annealing with elemental Se produced semiconducting FeSe2 whereas annealing with FeSe polycrystalline pellets produced superconducting FeSe with Tc(onset) ˜ 10 K. In the MBE growth, we attempted the growth similar to GaAs growth, namely with the vapor rich in Se, expecting self-limiting adsorption of Se. MBE films so far obtained with the growth temperature of 330 ^oC are nonsuperconducting hexagonal β-FeSe.

  5. Process and genes for expression and overexpression of active [FeFe] hydrogenases

    Science.gov (United States)

    Seibert, Michael; King, Paul W; Ghirardi, Maria Lucia; Posewitz, Matthew C; Smolinski, Sharon L

    2014-09-16

    A process for expression of active [FeFe]-hydrogenase in a host organism that does not contain either the structural gene(s) for [FeFe]-hydrogenases and/or homologues for the maturation genes HydE, HydF and HyG, comprising: cloning the structural hydrogenase gene(s) and/or the maturation genes HydE, HydF and HydG from an organisms that contains these genes into expression plasmids; transferring the plasmids into an organism that lacks a native [FeFe]-hydrogenase or that has a disrupted [FeFe]-hydrogenase and culturing it aerobically; and inducing anaerobiosis to provide [FeFe] hydrogenase biosynthesis and H?2#191 production.

  6. Fe(II)/Fe(III)-Catalyzed Intramolecular Didehydro-Diels-Alder Reaction of Styrene-ynes.

    Science.gov (United States)

    Mun, Hyeon Jin; Seong, Eun Young; Ahn, Kwang-Hyun; Kang, Eun Joo

    2018-02-02

    The intramolecular didehydro-Diels-Alder reaction of styrene-ynes was catalyzed by Fe(II) and Fe(III) to produce various naphthalene derivatives under microwave heating conditions. Mechanistic calculations found that the Fe(II) catalyst activates the styrenyl diene in an inverse-electron-demand Diels-Alder reaction, and the consecutive dehydrogenation reaction can be promoted by either Fe(II)-catalyzed direct dehydrogenation or an Fe(III)-catalyzed rearomatization/dehydrogenation pathway.

  7. Orujos de dos fases almacenados en balsas

    Directory of Open Access Journals (Sweden)

    Ruiz Méndez, Mª Victoria

    2004-09-01

    Full Text Available During the harvesting period 1999-2000, real samples of two phases olive pomace were taken from storage ponds in two extraction facilities located in Southern region of Spain , every month until a maximum of five months. In addition, lots of two phases olive pomace and second-centrifuged two phases olive pomace were divided in closed recipients and, also, in opened recipients, and were stored in laboratory at 36 ºC for 0, 1, 2, 4 and 6 months. Samples were analysed for moisture and fat content, and solvent-extracted; the resulting oils were analysed for acidity, fatty acid composition, polar compounds and triglycerides. The results indicate that oil deterioration increases throughout the storage period, particularly those oils extracted from surface and from second-centrifuged two phases olive pomace. The surface/volume ratio in the ponds should be as low as possible. Special attention should be paid to the storage of two phases olive pomace, establishing a maximum of two months in all cases.Durante la campaña 1999-2000 se han tomado muestras reales de orujo de balsas de almacenamiento, cada mes hasta un máximo de 5 meses, y de lotes de orujo de dos fases almacenados en el laboratorio, en recipientes cerrados y abiertos, a 36 ºC durante 0, 2, 4 y 6 meses, correspondientes a masas centrifugadas una y dos veces (repasada. Se han analizado la humedad y riqueza grasa de las muestras y la acidez, composición en ácidos grasos, compuestos polares y triglicéridos de los aceites extraídos con disolvente. Los resultados indican que no es aconsejable el almacenamiento del orujo de dos fases en balsas por un tiempo superior a dos meses ya que podría suponer un serio detrimento a la calidad del aceite obtenido, siendo mayor en aquellos de masas centrifugadas dos veces (repasadas y, sobre todo, en las zonas superficiales, por lo que las balsas deberían tener una relación superficie/volumen lo menor posible.

  8. Competencias adquiridas en la carrera de Medicina: Comparación entre egresados de dos universidades, una pública y otra privada

    Directory of Open Access Journals (Sweden)

    Amanda Galli

    Full Text Available Se entiende por competencia, la capacidad de hacer alguna cosa o la capacidad de cumplir una tarea. El propósito de este trabajo es conocer qué competencias profesionales han logrado los egresados; comprobar si existen diferencias entre dos grupos de egresados y establecer si existe alguna relación entre la cantidad de competencias que dicen haber logrado y la valoración global que hacen de la formación universitaria recibida. Se diseñó un cuestionario con 34 conductas profesionales (marcar sí cuando se siente capaz de realizarla en forma autónoma y una pregunta para valorar globalmente la formación recibida. El cuestionario se aplicó a dos grupos: egresados de una universidad pública (G1 y de una privada (G2. Los resultados se expresaron como porcentajes y medias de respuestas sí. Las 34 actividades se presentan agrupadas en 7 categorías. Se analizaron las diferencias entre ambos grupos. Respondieron 181 médicos, el promedio de respuestas positivas es de 28,18; diferencia significativa a favor del G1. El 100% de los egresados se sienten capaces de hacer una buena anamnesis y un examen físico completo. Los porcentajes más bajos de respuesta afirmativas se concentran en las conductas vinculadas a decisiones terapéuticas, a intervenciones en salud comunitaria y a habilidades para el autoaprendizaje. Sólo en 8 de las 34 conductas profesionales se hallaron diferencias significativas a favor de G1. El 53% de los egresados evalúa como Buena la formación recibida, no hay diferencia significativa entre ambos grupos. Se observa una correspondencia entre cantidad de respuestas sí y valoración de la formación recibida : a mejor valoración mayor número de respuestas positivas. Los resultados son similares en ambos grupos; los hallazgos están en consonancia con los de otros estudios publicados. Este tipo de cuestionario de autoevaluación puede ser uno de los instrumentos a utilizar en la evaluación de resultados de un programa de

  9. Response of soybean plants to the application of synthetic and biodegradable Fe chelates and Fe complexes.

    Science.gov (United States)

    Martín-Fernández, Clara; Solti, Ádám; Czech, Viktória; Kovács, Krisztina; Fodor, Ferenc; Gárate, Agustín; Hernández-Apaolaza, Lourdes; Lucena, Juan J

    2017-09-01

    The growing concern over the environmental risk of synthetic chelate application promotes the search for alternatives in Fe fertilization, such as biodegradable chelating agents and natural complexing agents. In this work, plant responses to the application of several Fe treatments (chelates and complexes) was analyzed to study their potential use in Fe fertilization under calcareous conditions. Thus, the root ferric chelate reductase (FCR) activity of soybean (Glycine max cv. Klaxon) plants was determined, and the effectiveness of the Fe chelates and complexes assessed in a pot experiment, by SPAD and fluorescence induction measurements, and the determination of Fe distribution in plant and soil. Additionally, (57)Fe Mössbauer spectroscopy was conducted to identify the Fe forms present in the soybean roots. The highest FCR activity was observed for the chelates EDDS/Fe(3+) and IDHA/Fe(3+); while no activity was observed when using complexes as Fe substrates. In contrast to the FCR data, the pot experiment confirmed that the o,oEDDHA/Fe(3+) is the most effective treatment, and the complexes LS/Fe(3+) and GA/Fe(3+) are able to alleviate Fe chlorosis, also indicated by SPAD data and the maximal quantum efficiency of photosystem II reaction centers as vitality parameters, and the enhanced plant uptake of Fe from natural sources. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  10. Mechanochemical synthesis of Fe-S materials

    DEFF Research Database (Denmark)

    Jiang, Jianzhong; Larsen, R.K.; Lin, R.

    1998-01-01

    Powder mixtures of metallic iron and sulfur have been milled in a high-energy planetary ball mill and the formation of iron sulfides has been studied by x-ray diffraction, Mossbauer spectroscopy, and scanning electron microscopy. For Fe:S ratios of 1:1 and 1:2 the final products are FeS with the ......Powder mixtures of metallic iron and sulfur have been milled in a high-energy planetary ball mill and the formation of iron sulfides has been studied by x-ray diffraction, Mossbauer spectroscopy, and scanning electron microscopy. For Fe:S ratios of 1:1 and 1:2 the final products are Fe......S with the modified NiAs structure and FeS2 (pyrite), respectively. No other iron sulfides were formed for any of the Fe:S ratios studied. The FeS phase has been tested as an electrode material in lithium batteries....

  11. Uso del módulo buena escritura y el déficit de atención en el aprendizaje de la ortografía en los estudiantes del quinto grado de primaria de la Institución Educativa Pública 7014 Vasil Levski del distrito de Surquillo

    OpenAIRE

    Heredia Rodríguez, Marcia María

    2015-01-01

    El uso del módulo Buena Escritura ha permitido disminuir el déficit de atención en el aprendizaje de la ortografía en los estudiantes del quinto grado del nivel de primaria de la Institución Educativa Pública 7014 Vasil Levski, del distrito de Surquillo, tal como se evidencian en la prueba de hipótesis principal y específicas. La discusión de resultados demostraron que el módulo como guía mejoró el uso correcto de las letras para la buena escritura en el grupo experimental, como también los a...

  12. Defesa dos direitos humanos: sistemas regionais

    Directory of Open Access Journals (Sweden)

    Hélio Bicudo

    2003-04-01

    Full Text Available O texto discorre sobre a institucionalização dos sistemas de promoção dos Direitos Humanos, ao longo do século XX. Tomando a Declaração Universal dos Direitos do Homem, de 1948, como base e ponto de partida, o articulista aborda as três principais vertentes dos sistemas de promoção desses direitos: a européia, a americana e a africana. A evolução de cada uma delas descrita analógica e epistemologicamente, de forma a salientar singularidades sem perder de vista as influências recíprocas ou mesmo as determinantes próprias do contexto espaço-social. Para finalizar, o articulista destaca a importância do Tribunal Penal Internacional no estabelecimento de uma justiça ecumênica. Concomitantemente, alerta para o perigo contido na ameaça de os EUA não o ratificarem.The text underlines the institutional character acquired by the main systems to promote Human Rights in the twentieth century. Taking the Universal Human Rigths Declaration, of 1948, as the basis for analysis, the author brings up three different approaches to promote these rights: the European, the American and the African. The evolution of each of them is described using its procedure as a basic reference. Besides, an analogical analysis, brings to the fore singularities, without ignoring reciprocal influences dictated by particular contexts, though. The author stresses the importance of the International Penal Court, as a means to establish ecumenical justice. At the same time, he reminds the reader of the risks implicit in the possible non-ratification of the IPC by United States.

  13. Dos nuevos puentes ligeros, en Alemania

    Directory of Open Access Journals (Sweden)

    Bay, Hermann

    1961-03-01

    Full Text Available Las dos obras, objeto de ligera descripción en este trabajo, dan patentes muestras de las direcciones generales en el orden constructivo hacia la belleza, esbeltez y función específica, objeto éste, que ha de cubrir las exigencias de la explotación pública, en este caso, de la obra.

  14. A segunda alma do partido dos trabalhadores

    Directory of Open Access Journals (Sweden)

    André Singer

    2010-12-01

    Full Text Available Os dois mandatos de Lula formaram a síntese contraditória das "duas almas" que hoje habitam o PT. Foi o fato de ter implementado, simultaneamente, políticas que beneficiam o capital e promovem a inclusão dos mais pobres, com uma melhora relativa na situação dos trabalhadores, que permitiu a convivência dos princípios estabelecidos em sua fundação, no colégio Sion em 1980, e as diretrizes do programa de governo apresentadas em 2002 na convenção do Anhembi, em São Paulo.Lula's presidency seem to have blended PT's two apparently contradictory "souls". By implementing policies that favor capital while at the same time foster the social inclusion of the poor, and that have also improved working class citizens' life standards, Lula has been able, as a president, to preserve the ideals that animated the party's foundation and the more pragmatic programme for government set out in 2002.

  15. Editorial - Rosa dos Ventos, Ano 7

    Directory of Open Access Journals (Sweden)

    Susana de Araujo Gastal

    2015-04-01

    Full Text Available Nossa Rosa dos Ventos chega ao seu ano 7, com sucesso de visualizações e de downloads. Nossa política editorial tem se pautado pela diversidade. Buscamos valorizar tanto os nomes consagrados da produção acadêmica, como jovens pesquisadores de talento, tanto em textos produzidos no Brasil como no exterior, e abrangendo uma ampla gama de temáticas. A RRV tem se marcado, ainda, pela diversidade de formato dos textos publicados: há artigos, ensaios, cases e resenhas críticas, de livro e evento, porque Ciência não se divulga em formato único.Rosa dos Ventos reaches its seventh-year milestone and during this period published successful articles in terms of unique viewers and content download. Our editorial guidelines are based on diversity. We have content from well-known authors, with an established academic research history, but also the young, talented, new generation have space. From Brazil or abroad, we have content covering a wide range of topics. RRV has also been marked by the variety of texts types. There are articles, essays, case studies and critical reviews, because, in the end, science is not published in only one standard format.

  16. ESCRITORAS BAIANAS DOS OITOCENTOS ENFRENTANDO PRECONCEITOS

    Directory of Open Access Journals (Sweden)

    Helena Parente Cunha

    2017-05-01

    Full Text Available Tem sido a conquista dos últimos anos o reconhecimento das autoras brasileiras dos séculos passados, mias numerosas do que se supunha e que foram esquecidas devido aos preconceitos do canone Literário. A partir da segunda metade do século XIX, com o levantamento dos períodos em todo o país, dirigidos e editados por mulheres e para mulheres, veiculavam as ideias avançadas e, ao mesmo tempo, concepções do sistema patriarcado. O medo do corpo e do erotismo se transmite à produção literária feminina que, ao se inspirar no amor, quase sempre usa linguagem pudica, procuando santificar o sentimento. Mas não raro surgem passagens de uma audácia inesperada, num desafio ostensivo aos convencionalizmos do cânone comportamental. Estudam-se como as escritoreas Ana Ribeiro, Ildefonsa Laura César e Adelio Fonseca, dentro deste contexto

  17. Radiation effects on interface reactions of U/Fe, U/(Fe + Cr), and U/(Fe + Cr + Ni)

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Lin, E-mail: lshao@tamu.edu [Department of Nuclear Engineering, Texas A and M University, College Station, TX 77843 (United States); Chen, Di; Wei, Chaochen; Martin, Michael S.; Wang, Xuemei [Department of Nuclear Engineering, Texas A and M University, College Station, TX 77843 (United States); Park, Youngjoo; Dein, Ed; Coffey, Kevin R.; Sohn, Yongho [Materials Science and Engineering, University of Central Florida, Orlando, FL 32816 (United States); Sencer, Bulent H.; Rory Kennedy, J. [Materials and Nuclear Fuel Performance, Idaho National Laboratory, Idaho Falls, ID 83415 (United States)

    2015-01-15

    We study the effects of radiation damage on interdiffusion and intermetallic phase formation at the interfaces of U/Fe, U/(Fe + Cr), and U/(Fe + Cr + Ni) diffusion couples. Magnetron sputtering is used to deposit thin films of Fe, Fe + Cr, or Fe + Cr + Ni on U substrates to form the diffusion couples. One set of samples are thermally annealed under high vacuum at 450 °C or 550 °C for one hour. A second set of samples are annealed identically but with concurrent 3.5 MeV Fe{sup ++} ion irradiation. The Fe{sup ++} ion penetration depth is sufficient to reach the original interfaces. Rutherford backscattering spectrometry analysis with high fidelity spectral simulations is used to obtain interdiffusion profiles, which are used to examine differences in U diffusion and intermetallic phase formation at the buried interfaces. For all three diffusion systems, Fe{sup ++} ion irradiations enhance U diffusion. Furthermore, the irradiations accelerate the formation of intermetallic phases. In U/Fe couples, for example, the unirradiated samples show typical interdiffusion governed by Fick’s laws, while the irradiated ones show step-like profiles influenced by Gibbs phase rules.

  18. Dos museos en México

    Directory of Open Access Journals (Sweden)

    Ramírez Vázquez, P.

    1967-03-01

    Full Text Available 1. Modem Art Museum, at México City This consists of two buildings, the Art Museum and the Art Gallery. The first has two floor levels and contains six circular halls for exhibitions, linked together by common utilities (public, administrative and maintenance offices, and by a large vestibule, which is also round and extends up to the second floor. The art gallery also has two floors, and has a circular exhibition hall on the second floor, and various services in the lower floor. A central vestibule connects both floors and the exterior. The formal expressivity of both blocks and the surrounding site are highly impressive because of their harmony and plasticity. 2. Ciudad Juárez Museum This museum has a central block, of circular base, which is occupied with four exhibition halls, and a second block, concentric with the first one, which also contains a number of exhibition rooms. The fortunate arrangement of volumes, their shape and texture, and their emplacement in the centre of a lake, make this an especially attractive building.1. Museo de arte Moderno, en la Ciudad de México El conjunto construido consta de dos edificios: el Museo de Arte y la Galería de Arte. El primero se ha resuelto en dos plantas, y alberga: seis salas circulares para exposiciones, unidas entre sí por los servicios comunes (públicos, administrativos y de entretenimiento, y un gran vestíbulo, también circular, de doble altura. El segundo se ha organizado asimismo en dos niveles, y consta de una sala circular para exposiciones en planta alta y servicios en planta baja, ligando ambas zonas por medio de un vestíbulo central, que los comunica al exterior. La expresividad formal de los dos cuerpos construidos y el paraje elegido para emplazarlos constituyen un acierto plástico y de ambientación. 2. Museo en Ciudad Juárez Comprende este edificio: un cuerpo central, de planta circular, que alberga: cuatro salas de exposiciones; y otro, concéntrico con el anterior

  19. Magnetostrictive GMR spin valves with composite FeGa/FeCo free layers

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Luping [Key Laboratory of Magnetic Materials and Devices & Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Institute of Materials Science, School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Zhan, Qingfeng, E-mail: zhanqf@nimte.ac.cn, E-mail: runweili@nimte.ac.cn; Yang, Huali; Li, Huihui; Zhang, Shuanglan; Liu, Yiwei; Wang, Baomin; Li, Run-Wei, E-mail: zhanqf@nimte.ac.cn, E-mail: runweili@nimte.ac.cn [Key Laboratory of Magnetic Materials and Devices & Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Tan, Xiaohua [Institute of Materials Science, School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China)

    2016-03-15

    We have fabricated strain-sensitive spin valves on flexible substrates by utilizing the large magnetostrictive FeGa alloy to promote the strain sensitivity and the composite free layer of FeGa/FeCo to avoid the drastic reduction of giant magnetoresistance (GMR) ratio. This kind of spin valve (SV-FeGa/FeCo) displays a MR ratio about 5.9%, which is comparable to that of the conventional spin valve (SV-FeCo) with a single FeCo free layer. Different from the previously reported works on magnetostrictive spin valves, the SV-FeGa/FeCo displays an asymmetric strain dependent GMR behavior. Upon increasing the lateral strain, the MR ratio for the ascending branch decreases more quickly than that for the descending branch, which is ascribed to the formation of a spiraling spin structure around the FeGa/FeCo interface under the combined influences of both magnetic field and mechanical strain. A strain sensitivity of GF = 7.2 was achieved at a magnetic bias field of -30 Oe in flexible SV-FeGa/FeCo, which is significantly larger than that of SV-FeCo.

  20. Magnetostrictive GMR spin valves with composite FeGa/FeCo free layers

    Directory of Open Access Journals (Sweden)

    Luping Liu

    2016-03-01

    Full Text Available We have fabricated strain-sensitive spin valves on flexible substrates by utilizing the large magnetostrictive FeGa alloy to promote the strain sensitivity and the composite free layer of FeGa/FeCo to avoid the drastic reduction of giant magnetoresistance (GMR ratio. This kind of spin valve (SV-FeGa/FeCo displays a MR ratio about 5.9%, which is comparable to that of the conventional spin valve (SV-FeCo with a single FeCo free layer. Different from the previously reported works on magnetostrictive spin valves, the SV-FeGa/FeCo displays an asymmetric strain dependent GMR behavior. Upon increasing the lateral strain, the MR ratio for the ascending branch decreases more quickly than that for the descending branch, which is ascribed to the formation of a spiraling spin structure around the FeGa/FeCo interface under the combined influences of both magnetic field and mechanical strain. A strain sensitivity of GF = 7.2 was achieved at a magnetic bias field of -30 Oe in flexible SV-FeGa/FeCo, which is significantly larger than that of SV-FeCo.

  1. Magnetostrictive GMR spin valves with composite FeGa/FeCo free layers

    Science.gov (United States)

    Liu, Luping; Zhan, Qingfeng; Yang, Huali; Li, Huihui; Zhang, Shuanglan; Liu, Yiwei; Wang, Baomin; Tan, Xiaohua; Li, Run-Wei

    2016-03-01

    We have fabricated strain-sensitive spin valves on flexible substrates by utilizing the large magnetostrictive FeGa alloy to promote the strain sensitivity and the composite free layer of FeGa/FeCo to avoid the drastic reduction of giant magnetoresistance (GMR) ratio. This kind of spin valve (SV-FeGa/FeCo) displays a MR ratio about 5.9%, which is comparable to that of the conventional spin valve (SV-FeCo) with a single FeCo free layer. Different from the previously reported works on magnetostrictive spin valves, the SV-FeGa/FeCo displays an asymmetric strain dependent GMR behavior. Upon increasing the lateral strain, the MR ratio for the ascending branch decreases more quickly than that for the descending branch, which is ascribed to the formation of a spiraling spin structure around the FeGa/FeCo interface under the combined influences of both magnetic field and mechanical strain. A strain sensitivity of GF = 7.2 was achieved at a magnetic bias field of -30 Oe in flexible SV-FeGa/FeCo, which is significantly larger than that of SV-FeCo.

  2. Moessbauer-spectroscopic study of structure and magnetism of the exchange-coupled layer systems Fe/FeSn{sub 2}, and Fe/FeSi/Si and the ion-implanted diluted magnetic semiconductor SiC(Fe); Moessbauerspektroskopische Untersuchung von Struktur und Magnetismus der austauschgekoppelten Schichtsysteme Fe/FeSn{sub 2} und Fe/FeSi/Si und des ionenimplantierten verduennten magnetischen Halbleiters SiC(Fe)

    Energy Technology Data Exchange (ETDEWEB)

    Stromberg, Frank

    2009-07-07

    In line with this work the structural and magnetic properties of the exchange coupled layered systems Fe/FeSn{sub 2} and Fe/FeSi/Si and of the Fe ion implanted diluted magnetic semiconductor (DMS) SiC(Fe) were investigated. The main measuring method was the isotope selective {sup 57}Fe conversion electron Moessbauer spectroscopy (CEMS), mostly in connection with the {sup 57}Fe tracer layer technique, in a temperature range from 4.2 K to 340 K. Further measurement techniques were X-ray diffraction (XRD), electron diffraction (LEED, RHEED), SQUID magnetometry and FMR (Ferromagnetic Resonance). In the first part of this work the properties of thin AF FeSn{sub 2}(001) films and of the exchange-bias system Fe/FeSn{sub 2}(001) on InSb(001) were investigated. With the application of {sup 57}Fe-tracer layers and CEMS both the Fe-spin structure and the temperature dependence of the magnetic hyperfine field (B{sub hf}) of FeSn{sub 2} could be examined. The evaporation of Fe films on the FeSn{sub 2} films produced in the latter ones a high perpendicular spin component at the Fe/FeSn{sub 2} interface. In some distance from the interface the Fe spins rotate back into the sample plane. Furthermore {sup 57}Fe-CEMS provided a correlation between the absolute value of the exchange field vertical stroke He vertical stroke and the amount of magnetic defects within the FeSn{sub 2}. Temperature dependent CEMS-measurements yielded informations about the spin dynamics within the AF. The transition temperatures T{sub B}{sup *}, which were interpreted as superparamagnetic blocking temperatures, obtain higher values compared to the temperatures T{sub B} of the exchange-bias effect, obtained with magnetometry measurements. The second part of this work deals with the indirect exchange coupling within Fe/FeSi/Si/FeSi/Fe multilayers and FeSi diffusion barriers. The goal was to achieve Fe free Si interlayers. The CEMS results show that starting from a thickness of t{sub FeSi}=10-12 A of the

  3. Definición de aspectos procedimentales y buenas prácticas para el servicio de asesoría del programa Aprendizaje en Línea en la Universidad Estatal a Distancia de Costa Rica

    Directory of Open Access Journals (Sweden)

    Francisco Mora-Vicarioli

    2017-08-01

    Full Text Available Este artículo muestra los resultados de una investigación, cuyo objetivo principal fue valorar los aportes del proceso de asesoría que facilita el Programa de Aprendizaje en Línea (PAL a las personas tutoras, coordinadoras y encargadas de cátedra o programa en los procesos de virtualización de sus asignaturas o cursos en línea de la Universidad Estatal a Distancia (UNED de Costa Rica, para el logro de una organización y mediación idónea de los entornos virtuales de aprendizaje según corresponda. Lo anterior, con el propósito de generar un acercamiento a aspectos procedimentales y buenas prácticas que se realizan desde el proceso orientador de la asesoría. El trabajo se desarrolló con el enfoque de investigación mixta. Se aplicó un instrumento en línea a una población usuaria de la asesoría, a partir de cuyo análisis se brinda una serie de hallazgos, en cuanto a los beneficios que se perciben, relevancia del diseño y organización que propicia la asesoría para la mejora de los cursos en línea, su organización, diseño y mediación, así también el valor de los manuales que provee el PAL para realizar procesos de configuración en las plataformas, entre otros aspectos.

  4. Diez claves pedagógicas para promover buenas prácticas en la formación médica basada en competencias en el grado y en la especialización

    Directory of Open Access Journals (Sweden)

    Pilar Ruiz de Gauna

    2015-01-01

    Full Text Available Durante la pasada década, la formación basada en competencias ha sido un término muy utilizado en Educación Médica. Los autores de este artículo argumentan que aunque se han desarrollado cambios relevantes en algunas facultades y centros sanitarios de formación de especialistas, en muchos otros lo único que ha cambiado es el nombre de las cosas para continuar haciendo lo mismo y no producir ninguna modificación en el perfil competencial de los estudiantes y los residentes. También se da el caso de instituciones que ni siquiera se plantean algún tipo de movimiento. Sin embargo, la situación social actual requiere pensar en una educación basada en competencias y establecer perfiles competenciales que respondan a las nuevas necesidades sociosanitarias. Por ello, el paso de una formación tradicional a una formación mediante competencias tiene que generalizarse y consolidarse en las instituciones educativas y sanitarias. Los autores del artículo argumentan que el cambio de la formación tradicional a otra apoyada en competencias tiene que liderarse desde las direcciones, los gestores y los docentes/tutores, y que las decisiones que ellos adopten han de estar fundamentadas en un marco pedagógico que concretan en 10 claves pedagógicas. Finalmente, concluyen que los currículos y programas de formación asentados en estas claves pedagógicas garantizan tanto el desarrollo de un perfil competencial de estudiantes y residentes comprometidos con un mundo más humano y más justo como el desarrollo de una buena práctica de formación en Educación Médica.

  5. Guía de buenas prácticas en Atención Primaria con perspectiva de género Best practices guide in Primary Care with a gender perspective

    Directory of Open Access Journals (Sweden)

    Eva Piqué Prado

    2011-12-01

    Full Text Available El artículo presenta una guía de buenas prácticas para contribuir desde la equidad de género a mejorar las condiciones de salud y procesos de atención de salud en Atención Primaria. Se centra en las siguientes prácticas: (1 Trabajar la promoción de salud de las mujeres en todas las etapas del ciclo vital a través de la educación para la salud grupal. (2 Fomento de la corresponsabilidad en el cuidado de las personas dependientes. (3 Promoción del ejercicio físico en mujeres. (4 Promoción de hábitos alimentarios saludables y prevención de enfermedades prevalentes relacionadas con la alimentación. (5 Prevención y detección de la violencia de género. (6 Utilización de un discurso sanitario no sexista ni androcéntrico.The article presents a practical guide to help from gender equity to improve health conditions and health care processes in primary care. It focuses on the following practices: (1 Working to promote women's health in all stages of life through health education group. (2 Promotion of shared responsibility in the care of dependents. (3 Promotion of physical activity in women. (4 Promotion of healthy eating habits and prevention of prevalent diseases related to food. (5 Prevention and detection of gender violence. (6 Use of a sanitary speech not sexist or androcentric.

  6. El cuidado a la salud bucal del anciano: buenas prácticas fundamentadas en el paradigma de la promoción de la salud Oral health care of the aged: good practices based on health promotion paradigm

    Directory of Open Access Journals (Sweden)

    Ana Lúcia Schaefer Ferreira de Mello

    2009-06-01

    Full Text Available Presenta la elaboración de un referente de buenas prácticas del cuidado a la salud bucal a la población anciana, basado en la Promoción de la Salud (PS. El método adoptado fue el de la Teoría Fundamentada en los Datos. El referencial teórico-práctico se describe para guiar el desarrollo de acciones en consonancia con el paradigma de la PS según la Carta de Ottawa y sus cinco áreas. Es necesario considerar estas prácticas de cuidado como un objetivo a alcanzar y contribuir al progreso sostenido en la calidad del cuidado y la transformación en las condiciones de salud bucal durante el curso de la vida.It presents the elaboration of a theoretical-practical referential of good oral health care practices to the aged population, based on the principles of Health Promotion (HP. The methodological referential adopted was Grounded Theory. The theoretical-practical referential is described to guide the development of oral health care actions to the aged, in consonance with the HP paradigm defended in the Ottawa Charter according to five areas. It is necessary to consider these care practices, that conform the theoretical-practical referential here detailed, as an objective to reach, to contribute to the sustained progress in the quality of the care and, consequently, promote a transformation in oral health conditions during life course.

  7. Interstitial Fe in MgO

    CERN Document Server

    Mølholt, T E; Gunnlaugsson, H P; Svane, A; Masenda, H; Naidoo, D; Bharuth-Ram, K; Fanciulli, M; Gislason, H P; Johnston, K; Langouche, G; Ólafsson, S; Sielemann, R; Weyer, G

    2014-01-01

    Isolated Fe-57 atoms were studied in MgO single-crystals by emission Mossbauer spectroscopy following implantation of Mn-57 decaying to Fe-57. Four Mossbauer spectral components were found corresponding to different Fe lattice positions and/or charge states. Two components represent Fe atoms substituting Mg as Fe2+ and Fe3+, respectively; a third component is due to Fe in a strongly implantation-induced disturbed region. The fourth component, which is the focus of this paper, can be assigned to Fe at an interstitial site. Comparison of its measured isomer shift with ab initio calculations suggests that the interstitial Fe is located on, or close to, the face of the rock-salt MgO structure. To harmonize such an assignment with the measured near-zero quadrupole interaction a local motion process (cage motion) of the Fe has to be stipulated. The relation of such a local motion as a starting point for long range diffusion is discussed.

  8. Effect of Iron Fe (II and Fe (III in a Binary System Evaluated Bioluminescent Method

    Directory of Open Access Journals (Sweden)

    Elena Sorokina

    2013-01-01

    Full Text Available The effect of iron ions Fe2+ and Fe3+ on the bioluminescent recombinant strain of Escherichia coli in a single-component and binary system. Found that for the bacteria E. coli Fe3+ ions are more toxic than Fe2+. Under the combined effect of iron toxicity increases, the percentage of luminescence quenching increases, but the value is much less than the sum of the indicator for the Fe2+ and Fe3+. The biological effect of insertion of iron is not proportional to their content in the mixture.

  9. O comportamento ético dos enfermeiros dos hospitais universitários

    Directory of Open Access Journals (Sweden)

    Raimunda Medeiros Germano

    Full Text Available Este trabalho teve como objetivos: - analisar a concepção da ética, presente no discurso e na prática dos enfermeiros; verificar a influência na formação dos estudantes de enfermagem e investigar sua contribuição para a compreensão da realidade moral e análise crítica da prática profissional. Na trajetória metodológica, privilegiou-se a análise qualitativa utilizando-se das técnicas de coleta de documentos, entrevistas coletivas e observações da prática cotidiana. Segundo a análise dos resultados, a concepção dos enfermeiros diz respeito à sua (insatisfação no trabalho, à discriminação profissional e às questões corporativas da equipe de saúde. São incipientes as questões éticas relacionadas à competência técnica, ao respeito ao paciente enquanto ser social e aos direitos de cidadania dos usuários. Ocorre, ainda um distanciamento de uma compreensão da ética enquanto comportamento moral e uma visão crítica da profissão e da assistência à saúde.

  10. Buenas ondas de la sociedad civil

    Directory of Open Access Journals (Sweden)

    José Ignacio López Vigil

    2015-01-01

    Full Text Available La esencia de la radio comunitaria radica en los objetivos sociales por los que luchamos, sostiene el autor. A diferencia de la finalidad lucrativa de las emisoras comerciales, estas radios ponen onda su energía al servicio de la comunidad. La comunicación comunitaria es una vocación social que concibe la comunicación como un medio, la sociedad y su mejoramiento es el fin. En el texto el autor intenta responder a ¿dónde está lo comunitario?

  11. Bolivia 2012: entre buenas y malas noticias

    National Research Council Canada - National Science Library

    Mendoza-Botelho, Martin

    2013-01-01

    .... Si bien la administracion de Morales logro dar respuesta a algunos de estos temas, adoptando un rol conciliador ante una creciente fragmentacion social, otros permanecen en la agenda, como el TIPNIS...

  12. Lattice locations and properties of Fe in Co/Fe co-implanted ZnO

    DEFF Research Database (Denmark)

    Gunnlaugsson, H.P.; Johnston, K.; Mølholt, T.E.

    2012-01-01

    The lattice locations and electronic configurations of Fe in 57Co/57Fe implanted ZnO (to (5‐6) × 1014 Fe/cm−2) have been studied by 57Fe Mössbauer emission spectroscopy. The spectra acquired upon room temperature implantation show ∼20% of the probe atoms as Fe2+ on perturbed Zn sites and the rema......The lattice locations and electronic configurations of Fe in 57Co/57Fe implanted ZnO (to (5‐6) × 1014 Fe/cm−2) have been studied by 57Fe Mössbauer emission spectroscopy. The spectra acquired upon room temperature implantation show ∼20% of the probe atoms as Fe2+ on perturbed Zn sites...... and the remaining fraction as Fe2+ in damage sites of interstitial character. After annealing at 773 K, ∼20% remain on crystalline sites, while the damage fraction has partly disappeared and instead a ∼30% fraction occurs as high‐spin Fe3+, presumably in precipitates. This suggests that precipitation of Co/Fe in ZnO...... likely takes place at relatively low temperatures, thus explaining some of the discrepancies in the literature regarding magnetic properties of 3d metal‐doped ZnO....

  13. Charge stripe structure in FeTe

    Energy Technology Data Exchange (ETDEWEB)

    Kawashima, Y., E-mail: yukik@eng.hokudai.ac.jp [Department of Applied Physics, Hokkaido University, Sapporo 060-8628 (Japan); Ichimura, K. [Department of Applied Physics, Hokkaido University, Sapporo 060-8628 (Japan); Center of Education and Research for Topological Science and Technology, Hokkaido University, Sapporo 060-8628 (Japan); Ishioka, J. [Department of Applied Physics, Hokkaido University, Sapporo 060-8628 (Japan); Kurosawa, T. [Department of Physics, Hokkaido University, Sapporo 060-0810 (Japan); Oda, M. [Center of Education and Research for Topological Science and Technology, Hokkaido University, Sapporo 060-8628 (Japan); Department of Physics, Hokkaido University, Sapporo 060-0810 (Japan); Yamaya, K. [Department of Applied Physics, Hokkaido University, Sapporo 060-8628 (Japan); Tanda, S. [Department of Applied Physics, Hokkaido University, Sapporo 060-8628 (Japan); Center of Education and Research for Topological Science and Technology, Hokkaido University, Sapporo 060-8628 (Japan)

    2012-06-01

    We report the STM study on a single-crystalline sample of FeTe at 7.8 K. FeTe is one of the iron-based superconductor. We measured the resistivity and the magnetization of FeTe. FeTe shows SDW transition at 58 K on these measurements. We study the electronic state of FeTe by using STM/STS for observing FeTe from a microscopic viewpoint. We observed the iron layer and the tellurium layer with atomic resolution. Moreover, we discover the charge stripe structure on STM/STS measurement. We find the charge stripe structure is caused by iron atoms from the analysis. The gap structure of 9 meV was observed in tunneling spectra. This gap size is consistent with the SDW gap which is expected from mean field theory with T{sub N}=58 K.

  14. A força dos dispositivos

    Directory of Open Access Journals (Sweden)

    Nicolas Dodier

    Full Text Available Resumo As ciências sociais podem se beneficiar de uma atenção particular ao lugar que ocupam os dispositivos na vida social. O interesse de uma tal perspectiva reflete-se nas pesquisas que, desde o final dos anos 1970, recorreram a essa noção. Mas a leitura desses trabalhos mostra igualmente, além da grande variedade de definições e objetivos associados ao conceito de dispositivo, certas dificuldades encontradas pelo caminho. Ela estimula um esforço de clarificação e renovação, tanto no plano conceitual como metodológico, contribuição procurada por este trabalho. Na primeira parte do artigo, apresentaremos os resultados de um levantamento conceitual sobre a noção de dispositivo. Na segunda parte, desenvolveremos uma série de proposições que visam elaborar uma abordagem “processual” dos dispositivos. Retomamos diversas pesquisas que conduzimos nessa perspectiva em torno de dispositivos de reparação: estudo do trabalho doutrinal de juristas em torno do processo penal, práticas dos advogados na audiência de um processo, reações de vítimas de uma catástrofe sanitária face a um fundo de indenização, transformações históricas de dispositivos de reparação de erros médicos desde o início do século XX.

  15. As religiões dos brasileiros

    Directory of Open Access Journals (Sweden)

    Pierre Sanchis

    2009-05-01

    Full Text Available Há dois movimentos simultâneos no campo religioso brasileiro: um primeiro de distinção, multiplicação e rupturas; um segundo de relativa homogeneização.  No campo cristão, o fenômeno mais visível é o da entrada maciça dos pentecostais, não só na arena religiosa em geral, mas nos seus pontos de alta visibilidade, especialmente populares. O significado da preferência dos pobres e do aparente trânsito do catolicismo ao pentecostalismo tende a representar o trânsito entre duas culturas: a tradicional católica afro-brasileira, e a cultura moderna de escolha individual.  A Nova Era, por exemplo, representa ao mesmo tempo a contudente negação de uma modernidade individualista, racional e dessacralizadora, a tentativa de recapitular, no que tem de global, espiritual, carnal e cósmico, o caminhar do homem para uma completude nunca atingida, porque nunca concluída.  Assim, o meio religioso brasileiro, sobretudo popular, mas não exclusivamente, vive num certo clima espiritualista que parece compartilhado por várias mentalidades no Brasil. Pode-se então levantar a seguinte questão: como escapar, neste nosso olhar sobre as religiões dos brasileiros, de uma visão tão linearmente evolucionista, positivista na sua concepção, repressiva na sua política?

  16. Morfologia dos tumores de hipofise em ratos

    Directory of Open Access Journals (Sweden)

    H. D. Mennel

    1977-12-01

    Full Text Available Foram analisados histologicamente 81 casos de adenomas de hipófise em ratos. Esses tumores foram observados em experimentos com carcinógenos de absorção. Essas substâncias produziram também outros tumores intracranianos. Um dos adenomas de hipófise assim obtido foi transplantado subcutaneamente, obtendo-se muitas passagens que foram seguidas histologicamente e ao microscópio eletrônico. Esses tumores foram também explantados "in vitro".

  17. Por uma carta dos bens fundamentais

    Directory of Open Access Journals (Sweden)

    Luigi Ferrajoli

    2010-07-01

    Full Text Available Este artigo questiona a possibilidade de a estipulação dos direitos fundamentais, e suas obrigações e proibições correspondentes, ser suficiente para garantir adequadamente as necessidades e os interesses vitais, em especial aqueles de interesse coletivo. São bens fundamentais aqueles cujo acesso é garantido a todos e a cada um, visto que são objetos dos direitos fundamentais subtraídos à lógica do mercado. A garantia de novos bens como bens fundamentais exige uma decisão política civilizatória de submeter ao direito as relações de mercado. Assim, às cartas e convenções internacionais e constitucionais de direitos fundamentais deveriam ser acrescentadas Cartas Constitucionais e Cartas Internacionais de bens fundamentais. Daí a necessidade de uma nova dimensão do constitucionalismo garantista: a longo prazo, além de global, para além da lógica individualista dos direitos e da miopia, e do estreito localismo da política das democracias nacionais.AbstractThis article addresses the question of whether the stipulation of fundamental rights and obligations and prohibitions related to them is sufficient to properly ensure the needs and vital interests, especially those from collective interest. Fundamental goods are those whose access is guaranteed to each and every one since they are the object of fundamental rights, excluded from the logic of the market. The warranty for new goods and basic goods in the bottom of civilization requires a political decision to submit the right market relations. Thus, to the international charters and conventions and fundamental constitutional rights should be added Charters and international charter of basic goods. Hence the need for a new dimension of the constitutionally guaranteed: a constitutionally guaranteed in the long term, and global, apart from the individualistic logic of rights and shortsightedness and narrow localism policy of national democracies.

  18. Displasias fibro-ósseas dos maxilares

    OpenAIRE

    Pacheco, Joana Isabel Alexandre

    2011-01-01

    Tese de mestrado, Medicina Dentária, Universidade de Lisboa, Faculdade de Medicina Dentária, 2011 A displasia fibrosa em conjunto com as displasias ósseas dos maxilares representam o grupo das displasias fibro-ósseas. Estas, apesar de partilharem as mesmas características histopatológicas e apresentarem uma substituição de osso normal por tecido fibroso e conjuntivo, diferem nas suas manifestações clínicas, no seu comportamento e têm abordagens terapêuticas diferentes. A displasia fibrosa ...

  19. DOS MUJERES: EL TATUAJE DE LA VIOLENCIA

    Directory of Open Access Journals (Sweden)

    RHINA MARTÍNEZ ANDRÉ LANDOS MARTÍNEZ ANDRÉ

    2008-11-01

    Full Text Available En Canción de Rachel (1969 de Miguel Barnet y Beco da fome (1972 de Orígenes Lessa dos mujeres, “bailarina” una, prostituta la otra –Rachel y Suely– narran sus historias de vida en las que cuerpo y alma se perfilan fragmentados y violentados. Analizar las relaciones de poder y la violencia que sufren las protagonistas con las contribuciones teóricas de Michel Foucault, Wilton García y Alexis Jardines, es el objeto de este trabajo.

  20. Equilibrio parcial y general: dos problemas inquietantes

    OpenAIRE

    Contreras Herrada, Tania; Mendieta Muñoz, Ivan Mendieta Muñoz; Huerta Quintanilla, Rogelio

    2012-01-01

    A pesar de los múltiples avances y modificaciones que ha sufrido la teoría microeconómicaneoclásica, sus dos modelos canónicos continúan siendo el de equilibrio parcial y el de equilibriogeneral. Contrario a lo que habitualmente se expone, existe abundante literatura que tornainsatisfactorios a ambos instrumentos analíticos. El presente ensayo intenta exponer algunosproblemas de la teoría microeconómica dominante recuperando los trabajos que nos parecencontienen los componentes más esenciales...

  1. Preparation of γ-Fe2O3/Ni2O3/FeCl3(FeCl2 Composite Nanoparticles by Hydrothermal Process Useful for Ferrofluids

    Directory of Open Access Journals (Sweden)

    Qingmei Zhang

    2011-01-01

    Full Text Available Using a hydrothermal process in FeCl2 solution, γ-Fe2O3/Ni2O3/FeCl3(FeCl2 composite nanoparticles were obtained from the FeOOH/Ni(OH2 precursor prepared by coprecipitation. The precursor and the as-prepared nanoparticles were investigated by vibrating sample magnetometer (VSM, X-ray diffraction (XRD, energy disperse X-ray spectroscopy (EDX, X-ray photoelectron spectroscopy (XPS, and transmission electron microscopy (TEM. The experimental results showed that the paramagnetic amorphous precursor, in which Ni(OH2 is formed outside FeOOH, is transformed to ferrimagnetic γ-Fe2O3/Ni2O3 composite when it is processed in FeCl2 solution (0.25, 0.50, 1.00 M in an autoclave at 100°C for 1 hr. In addition, the dismutation reaction of FeCl2 produces FeCl3 and Fe. Some FeCl3 and little FeCl2 can be absorbed to form γ-Fe2O3/Ni2O3/FeCl3(FeCl2 composite nanoparticles in which Ni2O3 forms outside the γ-Fe2O3 core and the outermost layer is FeCl3 (FeCl2. The content of FeCl3 (FeCl2 in the particles increased, and the magnetization of the particles decreased with the concentration of FeCl2 solution increasing in the hydrothermal process. The FeCl3 (FeCl2 surface is chemically passive and nonmagnetic (paramagnetic. Accordingly, the composite nanoparticles are chemically stable, and their aggregation is prevented. The specific saturation magnetization of such composite nanoparticles can get to 57.4–62.2 emu/g and could be very suitable for synthesizing ferrofluids.

  2. Avaliação comparativa e evolutiva dos protocolos de atendimento dos pacientes fissurados

    OpenAIRE

    Alonso, Nivaldo; Tanikawa,Daniela Yukie Sakai; Lima Junior, Jonas Eraldo de; Ferreira,Marcus Castro

    2010-01-01

    INTRODUÇÃO: Os protocolos de atendimento multiprofissional são tentativas para obtenção dos melhores resultados estéticos e funcionais possíveis no tratamento dos pacientes fissurados. OBJETIVO: Este estudo tem por objetivo analisar comparativamente os resultados obtidos no primeiro e no segundo ano após a implantação do protocolo de atendimento multiprofissional, buscando evidenciar as diferenças significativas encontradas após maior tempo de experiência desta padronização terapêutica. MÉTOD...

  3. Estudio de inmunogenicidad para dos vacunas recombinantes contra hepatitis B

    OpenAIRE

    O. Juliao; González, A.; V. Ramírez; Rojas, M. C.; Boschell, J; L. S. Hernández; T. E. Camacho; Martínez, M.; Saad, C.; de la Hoz, F; González, M.; Avendaño,J; Silva, A. (Álvaro); J. Pabón; Giraldo, A.

    1991-01-01

    Este estudio compara la inmunogenicidad (seroconversión, seroprotección e Hiperrespuesta), producida por dos vacunas recombinantes contra la hepatitis B (Engerix-B de Bélgica y Cubana), en dos esquemas (012 y 016 meses), empleando los métodos de cuantificación para Anti-HBsAg (Abbott y Organón), los cuales fueron también comparados. En el estudio participaron 257 voluntarios,  divididos al azar en 4 grupos (dos vacunas, dos esquemas). Resultados: los dos métodos de Abbon y Organon, no present...

  4. Fe-V redox flow batteries

    Science.gov (United States)

    Li, Liyu; Kim, Soowhan; Yang, Zhenguo; Wang, Wei; Zhang, Jianlu; Chen, Baowei; Nie, Zimin; Xia, Guanguang

    2014-07-08

    A redox flow battery having a supporting solution that includes Cl.sup.- anions is characterized by an anolyte having V.sup.2+ and V.sup.3+ in the supporting solution, a catholyte having Fe.sup.2+ and Fe.sup.3+ in the supporting solution, and a membrane separating the anolyte and the catholyte. The anolyte and catholyte can have V cations and Fe cations, respectively, or the anolyte and catholyte can each contain both V and Fe cations in a mixture. Furthermore, the supporting solution can contain a mixture of SO.sub.4.sup.2- and Cl.sup.- anions.

  5. Growth kinetics of thin oxide layers; oxidation of Fe and Fe-N phases at room temperature

    NARCIS (Netherlands)

    Kooi, Bart J.; Somers, Marcel A.J.; Mittemeijer, Eric J.

    1996-01-01

    The evolution of iron-oxide layers at room temperature on pure polycrystalline α-Fe and on the Fe-N phases γ-Fe[N], γ'-Fe4N1-x and ε-Fe2N1-z was followed in situ with Auger-Electron Spectroscopy. The observed oxidation kinetics of the Fe and Fe-N phases were interpreted using a model considering

  6. The Spectrum of Fe II

    Science.gov (United States)

    Nave, Gillian; Johansson, Sveneric

    2013-01-01

    The spectrum of singly ionized iron (Fe II) has been recorded using high-resolution Fourier transform (FT) and grating spectroscopy over the wavelength range 900 Å to 5.5 μm. The spectra were observed in high-current continuous and pulsed hollow cathode discharges using FT spectrometers at the Kitt Peak National Observatory, Tucson, AZ and Imperial College, London and with the 10.7 m Normal Incidence Spectrograph at the National Institute of Standards and Technology. Roughly 12,900 lines were classified using 1027 energy levels of Fe II that were optimized to measured wavenumbers. The wavenumber uncertainties of lines in the FT spectra range from 10-4 cm-1 for strong lines around 4 μm to 0.05 cm-1 for weaker lines around 1500 Å. The wavelength uncertainty of lines in the grating spectra is 0.005 Å. The ionization energy of (130,655.4 ± 0.4) cm-1 was estimated from the 3d6(5D)5g and 3d6(5D)6h levels.

  7. Determination of [Fe2+]/[Fe3+]-ratios in Arfvedsonite by Mössbauer Spectroscopy

    DEFF Research Database (Denmark)

    Andersen, E. B.; Fenger, J.; Rose-Hansen, J.

    1975-01-01

    to correct for a difference between the recoil-free fractions. At room temperature [Fe2+] seems detected with an efficiency of only about 85% of that of [Fe3+]. Results of [Fe2+]/[Fe3+] determinations by Mössbauer spectroscopy and by wet chemical analysis of a series of arfvedsonite samples, separated from...... various rocks from the Ilimaussaq intrusion, south Greenland, are compared and agree reasonably well....

  8. Autonomia e vulnerabilidade na vida dos adolescentes

    Directory of Open Access Journals (Sweden)

    Renata R. de Oliveira

    2007-05-01

    Full Text Available Este trabalho foi realizado com a finalidade de estabelecer relações entre os princípios éticos da autonomia e vulnerabilidade e a vida de adolescentes, pessoas reconhecidamente passíveis de síndromes depressivas, uso abusivo de drogas ilícitas, alcoolismo e tabagismo. Famílias desestruturadas, pais ausentes, companhia de amigos que levam a diferentes vícios, facilidade de acesso a fontes desencontradas de informações e uma sociedade indiferente afetam o desenvolvimento normal dos jovens. Considera-se, ainda, o grande desafio apresentado a profissionais de saúde em agir na busca de reduzir a vulnerabilidade dos adolescentes e permitir que os mesmo usem de autonomia com responsabilidade na tomada de decisões em suas vidas pessoais. O cuidado com os mesmos deve ser mais integral e ativo e a sociedade ainda não reconheceu adequadamente a importância de cuidar do desenvolvimento saudável desse imenso contingente humano.

  9. Através dos espelhos

    Directory of Open Access Journals (Sweden)

    Jean D. Soares

    2017-12-01

    Full Text Available Ao refletir sobre a experiência através de espelhos, esse texto pensa a relação entre sujeito e imagem a partir dos conceitos de utopia e de heterotopia. Ao longo dos parágrafos, ele parte de exemplos cotidianos para se confrontar com os casos em que os direitos da imagem encontram situações limite, nomeadamente a partir de algumas reflexões de Michel Focault. Levantam-se aqui ao menos duas hipóteses importantes: a de que uma imagem utópica da existência traz perigos que não se podem menosprezar, e uma segunda sobre a possibilidade de uma alternativa capaz de rearranjar esses riscos em torno da experiência estética. Pretende-se com isso fomentar o debate ligado à discussão sobre nossa capacidade de dar conta das imagens que transmitimos para nós mesmos.

  10. enoturismo no Vale dos Vinhedos/RS

    Directory of Open Access Journals (Sweden)

    Hernanda Tonini

    2008-01-01

    Full Text Available The various types of tourism aim to consolidate the activity as a product, marketing leisure, culture, past and present targeted to what drives the tourist. Given that, this study aimed to analyze the role played by the government and by public policies designed to chart a course for a touristic tipology in growth: the wine tourism, trips motivated from the interest in the wine and the producer region. The qualitative field method was implemented through descriptive-exploratory research characterized by a case study in the Vale dos Vinhedos. A collection of basic data was compiled from interviews with local private sector representatives and Secretaries of Tourism in the Bento Gonçalves, Monte Belo do Sul and Garibaldi municipalities, all located in this region. Among the findings, the Government participate in important points to build the route, however the lack of a policy specifically targeted to the wine tourism tends to compromise its development in the Vale dos Vinhedos.

  11. Factor de riesgo suicida según dos cuestionarios, y factores asociados en estudiantes de la universidad nacional de Colombia sede Manizales

    Directory of Open Access Journals (Sweden)

    José Jaime Castaño Castrillón

    2015-01-01

    Full Text Available Objetivo: Determinar el factor de riesgo ( fr suicida según dos cuestionarios y factores asociados que presentan los estudiantes de la Universidad Nacio - nal de Colombia, sede Manizales (Caldas, Colombia en la jornada diurna. Materiales y métodos: La investigación fue de tipo corte transversal; la población estuvo constituida por 255 estudiantes de 3 facultades de la Universidad. Resultados: Prevalen - cia de riesgo suicida: 6,7 %, según Plutchik; 19,7 %, según Beck. Buena funcionalidad familiar: 39,8 %. Depresión ausente: 55,7 %. Se encontró una relación significativa entre el FR suicida, según Plutchik, y factores como el género, el gusto por el metal y la balada, la práctica de un deporte, hacer aeróbicos, la presencia de cuadros depresivos y la funcionali - dad familiar. Según Beck, dichos factores son género musical metal, depresión y funcionalidad familiar. Conclusiones: La prevalencia de riesgo suicida en esta población es inferior a la encontrada en otros estudios en poblaciones similares.

  12. De dragones, cascos y soldados de fortuna en el Occidente Antiguo. acerca de dos obras recientes sobre el mercenariado galo e hispano

    Directory of Open Access Journals (Sweden)

    García Jiménez, Gustavo

    2015-12-01

    Full Text Available Research on ancient mercenaries is fraught with problems, being the match between the scarce and partial data provided by the literary sources and the archaeological record a tricky and difficult matter. The recent publication of two books dealing with Iberian and Celtic mercenaries, by Raimon Graells and Luc Baray respectively, offers us an opportunity to dwell on a pervading discussion when studying cultural and military dynamics, and long distance relationships in Ancient Western Europe.La actividad mercenaria en la Antigüedad es uno de los campos de estudio más complejos de la investigación histórica, en buena medida debido a la difícil combinación que existe entre los siempre parciales datos de las fuentes literarias y la arqueología. La reciente publicación de dos monografías dedicadas al mercenario ibérico y celta, a cargo respectivamente de Raimon Graells y Luc Baray, nos brinda una magnífica oportunidad para retomar una vieja discusión siempre latente en el estudio de las dinámicas bélicas y culturales, y que nos permite ahondar en las intrincadas relaciones a larga distancia en el Occidente europeo antiguo.

  13. Evaluación de la exposición ambiental a plaguicidas orgánicos persistentes en dos barrios de la provincia de Córdoba

    Directory of Open Access Journals (Sweden)

    Patricia Lucero

    2008-12-01

    Full Text Available Se determinó la concentración de plaguicidas organoclorados en 167 muestras de sangre entera de habitantes de dos barrios (Sitio Nº 1 y Sitio Nº 2 de la provincia de Córdoba ubicados en los alrededores de depósitos de plaguicidas obsoletos. La presencia de plaguicidas se determinó por cromatografía gaseosa con detector de captura electrónica utilizando columnas capilares de distinta polaridad. Los plaguicidas más frecuentemente encontrados fueron p,p'-DDE, β-HCH y HCB. La máxima concentración detectada fue 7,31 µg/l y correspondió a p,p'-DDE. El β-HCH mostró valores más altos que los otros isómeros en la familia de los hexaclorociclohexanos (HCH. Se observó buena correlación entre la concentración de p,p'-DDE y la edad tal como se esperaba para un contaminante persistente y bioacumulable. El trabajo aporta información sobre los niveles de plaguicidas organoclorados en sangre en una población con exposición ambiental estudiada frente a denuncias periodísticas y de los mismos habitantes del lugar.

  14. Ab initio calculations of the Fe(II) and Fe(III) isotopic effects in citrates, nicotianamine, and phytosiderophore, and new Fe isotopic measurements in higher plants

    Science.gov (United States)

    Moynier, Frédéric; Fujii, Toshiyuki; Wang, Kun; Foriel, Julien

    2013-05-01

    Iron is one of the most abundant transition metal in higher plants and variations in its isotopic compositions can be used to trace its utilization. In order to better understand the effect of plant-induced isotopic fractionation on the global Fe cycling, we have estimated by quantum chemical calculations the magnitude of the isotopic fractionation between different Fe species relevant to the transport and storage of Fe in higher plants: Fe(II)-citrate, Fe(III)-citrate, Fe(II)-nicotianamine, and Fe(III)-phytosiderophore. The ab initio calculations show firstly, that Fe(II)-nicotianamine is ˜3‰ (56Fe/54Fe) isotopically lighter than Fe(III)-phytosiderophore; secondly, even in the absence of redox changes of Fe, change in the speciation alone can create up to ˜1.5‰ isotopic fractionation. For example, Fe(III)-phytosiderophore is up to 1.5‰ heavier than Fe(III)-citrate2 and Fe(II)-nicotianamine is up to 1‰ heavier than Fe(II)-citrate. In addition, in order to better understand the Fe isotopic fractionation between different plant components, we have analyzed the iron isotopic composition of different organs (roots, seeds, germinated seeds, leaves and stems) from six species of higher plants: the dicot lentil (Lens culinaris), and the graminaceous monocots Virginia wild rye (Elymus virginicus), Johnsongrass (Sorghum halepense), Kentucky bluegrass (Poa pratensis), river oat (Uniola latifolia), and Indian goosegrass (Eleusine indica). The calculations may explain that the roots of strategy-II plants (Fe(III)-phytosiderophore) are isotopically heavier (by about 1‰ for the δ56Fe) than the upper parts of the plants (Fe transported as Fe(III)-citrate in the xylem or Fe(II)-nicotianamine in the phloem). In addition, we suggest that the isotopic variations observed between younger and older leaves could be explained by mixing of Fe received from the xylem and the phloem.

  15. Stability and Elastic, Electronic, and Thermodynamic Properties of Fe2TiSi1- x Sn x Compounds

    Science.gov (United States)

    Jong, Ju-Yong; Yan, Jihong; Zhu, Jingchuan; Kim, Chol-Jin

    2017-10-01

    We have systematically studied the structural, phase, and mechanical stability and elastic, electronic, and thermodynamic properties of Fe2TiSi1- x Sn x ( x = 0, 0.25, 0.5, 0.75, 1) compounds using first-principles calculations. The structural and phase stability and elastic properties of Fe2TiSi1- x Sn x ( x = 0, 0.25, 0.5, 0.75, 1) indicated that all of the compounds are thermodynamically and mechanically stable. The shear modulus, bulk modulus, Young's modulus, Poisson's ratio, electronic band structure, density of states, Debye temperature, and Grüneisen parameter of all the substituted compounds were studied. The results show that Sn substitution in Fe2TiSi enhances its stability and mechanical and thermoelectric properties. The Fe2TiSi1- x Sn x compounds have narrow bandgap from 0.144 eV and 0.472 eV for Sn substitution from 0 to 1. The calculated band structure and density of states (DOS) of Fe2TiSi1- x Sn x show that the thermoelectric properties can be improved at substituent concentration x of 0.75. The lattice thermal conductivity was significantly decreased in the Sn-substituted compounds, and all the results indicate that Fe2TiSi0.25Sn0.75 could be a new candidate high-performance thermoelectric material.

  16. Properties of porous FeAlOy/FeAlx ceramic matrix composite ...

    Indian Academy of Sciences (India)

    Porous ceramic matrix composites FeAlO/FeAl with incorporated metal inclusions (cermets) were synthesized by pressureless method, which includes hydrothermal treatment of mechanically alloyed FeAl powder followed by calcination. Their main structural, textural and mechanical features are described. Variation of ...

  17. Phase Stability in the Fe-Rich Fe-Cr-Ni-Zr Alloys

    Science.gov (United States)

    Chen, Tianyi; Yang, Ying; Tan, Lizhen

    2017-10-01

    Knowledge on phase stability in Fe-rich Fe-Cr-Ni-Zr alloys is needed for the development of Laves phase strengthened Fe-Cr-Ni-Zr ferritic alloys. These alloys show promising applications as new cladding materials of nuclear reactors due to enhanced high-temperature strength and resistance to creep and irradiation hardening. Phase stability in four Fe-rich Fe-Cr-Ni-Zr alloys was carefully investigated using scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction techniques. The samples were arc-melted and heat treated at 973.15 K (700 °C) for 1275 hours and 1273.15 K (1000 °C) for 336 hours. The experimental results showed extensive solubility of Ni in the intermetallic phases Fe23Zr6 and Fe2Zr_C15. Nickel stabilizes the Laves Fe2Zr_C15 structure more than the C36 and C14 structures. In addition to Fe23Zr6 and Fe2Zr_C15, Ni7Zr2 was found to be stable in samples with higher Ni content and lower annealing temperature. The Fe2Zr_C15 and Fe23Zr6 coexist with the body-centered cubic matrix phase in all samples regardless of compositions and temperatures.

  18. O efeito combinado dos estilos de apego dos pais no estabelecimento dos estilos de apego de seus filhos

    OpenAIRE

    Silva, Marcílio Ângelo e

    2013-01-01

    o presente estudo apresenta uma ampla revisão sobre a produção acadêmica acerca da Teoria do Apego, partindo desde os primórdios de sua elaboração por John Bowlby (1969) e posteriormente Mary Ainsworth e colaboradores (1978) até as mais recentes explorações sobre o tema, enfatizando a ausência de estudos na área que avaliem a relação de tríades (pais, mães e filhos) de etnia não branca, de classe socioeconômica baixa e média e do contexto brasileiro, e as interações dos estilos de apego daque...

  19. ACERCA DOS PROCESSOS DE INDIGENIZAÇÃO DOS MUSEUS: UMA ANÁLISE COMPARATIVA

    Directory of Open Access Journals (Sweden)

    Andrea Roca

    2015-04-01

    Full Text Available A partir de uma leitura comparativa sobre a agência indígena no Museu Magüta (primeiro museu indígena do Brasil, pertencente ao povo Ticuna, localizado em Benjamin Constant, Amazonas e nas mostras do povo Musqueam no Museu de Antropologia da University of British Columbia (pioneiro na implementação do trabalho colaborativo com os povos indígenas, localizado em Vancouver, Canadá, este trabalho aborda modalidades coexistentes da chamada indigenização dos museus. Interessa-me distinguir as epistemologias e as políticas envolvidas na construção dos conteúdos indígenas desses espaços e sua autorrepresentação, problematizando a expressão "indigenização dos museus" e refletindo, ao mesmo tempo, sobre aquilo que se reconstrói, em termos dos cenários museológicos, após as situações coloniais

  20. Exchange biased FeNi/FeMn bilayers with coercivity and switching field enhanced by FeMn surface oxidation

    Directory of Open Access Journals (Sweden)

    A. V. Svalov

    2013-09-01

    Full Text Available FeNi/FeMn bilayers were grown in a magnetic field and subjected to heat treatments at temperatures of 50 to 350 °C in vacuum or in a gas mixture containing oxygen. In the as-deposited state, the hysteresis loop of 30 nm FeNi layer was shifted. Low temperature annealing leads to a decrease of the exchange bias field. Heat treatments at higher temperatures in gas mixture result in partial oxidation of 20 nm thick FeMn layer leading to a nonlinear dependence of coercivity and a switching field of FeNi layer on annealing temperature. The maximum of coercivity and switching field were observed after annealing at 300 °C.

  1. Impactos dos fundos setoriais nas empresas

    Directory of Open Access Journals (Sweden)

    Patrick Alves

    2012-07-01

    Full Text Available Os fundos setoriais foram instituídos no final da década de 1990, com o propósito de criar condições mais estáveis de financiamento público às atividades de ciência, tecnologia e inovação (CT&I no Brasil. De maneira análoga ao que se observa com outros instrumentos de incentivo à inovação nas empresas, a expectativa é que o acesso aos fundos setoriais contribuiria para o aumento dos esforços tecnológicos e para o alcance de melhores resultados pelas empresas. O objetivo deste trabalho é, portanto, avaliar o impacto desses fundos sobre os esforços tecnológicos e sobre os resultados das empresas industriais no Brasil, no período 2001 a 2006. A base teórica para a discussão é a literatura internacional que tem, recorrentemente, analisado o efeito crowding in ou crowding out de políticas de apoio à inovação nas empresas. Esses trabalhos buscam verificar se as políticas adotadas complementam os recursos alocados nas atividades de inovação pelas empresas ou se haveria simplesmente a substituição desses últimos por recursos públicos. Neste artigo, uma técnica quasi-experimental é aplicada para comparar as empresas que acessaram os fundos setoriais com aquelas que não os acessaram, usando dados de painel que incluem informações sobre esforços tecnológicos e resultados. O grupo de controle é definido com base no algoritmo de Propensity Score Matching (PSM, visando eliminar o viés de seleção no acesso aos fundos, o que faz com que, a priori, as empresas que acessam esses recursos trilhem uma trajetória distinta daquelas que não acessam. Estimativas das diferenças percentuais das taxas de crescimento dos esforços tecnológicos indicam significativo descolamento entre os grupos de tratamento e controle e permitem que se rejeite a hipótese de crowding out. Estima-se que o diferencial na taxa de crescimento do PoTec – que corresponde à proxy para os esforços tecnológicos – seja de 6,8 p.p. no primeiro

  2. LOS PROCESOS DE INNOVACIÓN EDUCATIVA EN LA FORMACIÓN UNIVERSITARIA, NUEVOS GENERADORES DE BUENAS PRÁCTICAS EN TECNOLOGÍA EDUCATIVA EDUCATIVE INNOVATION PROCESS IN UNIVERSITY FORMATION, NEW PRODUCTIVE BESTS PRACTICES IN EDUCATIVE TECHNOLOGY

    Directory of Open Access Journals (Sweden)

    Bartolomé Rubia-Avi

    2010-02-01

    Full Text Available La influencia de la innovación educativa en la transformación de la Universidad Española para el Reforma Europea de la Enseñanza Superior es un aspecto crucial. Varios aspectos están haciendo que características del modelo formativo tradicional, tengan que ser revisadas a la luz de las demandas sociales y la mejora necesaria de esta formación. Pero este cambio está siendo generado por pequeños grupos de docentes que, imbuidos por la necesidad de transformar su práctica educativa, a partir de pequeños grupos, generan “Comunidades de Práctica” donde reflexionan y toman decisiones sobre buenas prácticas. Las TICs son el eje de dichas mejoras, siendo este trabajo un pequeño esbozo de una de esas experiencias llevadas a cabo por un grupo de personas del Grupo de Investigación Reconocido de la Universidad de Valladolid, GSIC-EMIC, asociado a varias de estos grupos de profesores y profesoras, que están trabajando en transformar su práctica diaria desde hace algunos años. The influence of educational innovation in the transformation of Spanish Universities to achieved the goals posed by the European Higher Education Area is a crucial aspect for this reform. This process of deep impact within the European countries is promoting the revision of traditional teaching methods. Small groups of teachers and communities of practice are leading this revision by reflecting upon the main issues affecting the higher education system at the same time that they propose horizontal innovations to overcome them. Information and Communication Technologies are becoming of special relevance with regard to the aforementioned innovations. This paper describes a experience conducted within the GSIC-EMIC research team that illustrates the efforts done by a community of teachers at the University of Valladolid (Spain to analyze and improve their own teaching practices.

  3. ANÁLISIS DE “BUENAS PRÁCTICAS” DEL E-LEARNING EN LAS UNIVERSIDADES ANDALUZAS ANALYSIS OF "BEST PRACTICES" OF E-LEARNING IN ANDALUSIAN UNIVERSITIES

    Directory of Open Access Journals (Sweden)

    Julio Cabero Almenara

    2010-02-01

    Full Text Available Este artículo ofrece los resultados obtenidos del analisis de “buenas prácticas” de treinta profesores de las diferentes Universidades Andaluzas. Para la recogida de datos se han utilizado tres instrumentos: biograma, entrevistas individualizadas y observación de materiales. Estos profesores tienen una actitud positiva hacia la formación e-learning, trabajan en grupo y llevan más de 2 años impartiéndolas junto a la presencial. Consideran esta formación como una gran ayuda para los alumnos por el volumen de material disponible, la flexibilización en su uso, la posibilidad de consulta y el trato es más personal. Por otro lado, estos profesores señalan la cantidad de tiempo y esfuerzo que requiere la elaboración y actualización de los materiales. Así como la escasa formación para su utilización didáctica y educativa, subsanada por su autoformación. Los materiales utilizados son considerados como buenos en lo técnico, didáctico y comunicativo.This article provides the results of the analysis of "best practices" of thirty teachers of different Andalusian Universities. For the collection of data we have been used three instruments: biogram, individualized interviews and observation of materials. These teachers have a positive attitude towards e-learning, working in groups and carry more than 2 years teaching with (together the face to face. They consider this training as a high help to students because of the high volume of available material, application flexibility, the possibility of consultation and the treatment is more personal. Moreover, these teachers pointed out the amount of time and effort required for the preparation and updating of materials, and also here poor training for teaching and educational use, that is remedied by themselves. The materials used are is adecuated in the technical, teaching and in the communication way.

  4. La mirada de Watson, Parse y Benner para el análisis complejo y la buena práctica The glance of Watson, Pair and Benner for the complex analysis and the good practice

    Directory of Open Access Journals (Sweden)

    Sagrario Acebedo-Urdiales

    2007-06-01

    Full Text Available La necesidad de encontrar el significado y orden del quehacer enfermero por encima de especialidades, culturas, tareas, funciones o competencias, hace necesario llevar a la práctica teorías y conceptos de análisis que se puedan insertar en cada situación, como fundamento que guía la buena práctica enfermera. Los modelos y filosofías enfermeras nos dan elementos de reflexión, nos siembran la duda respecto a la práctica, nos dan elementos de investigación y cuando los integramos o nos reconocemos en ellos, además de flexibilizar la interpretación y el cuidado persona-situación, colocan a la enfermería dentro de su marco más maduro consistente con el modelo de Nithingale actualizado. Este trabajo tiene como objetivo plantear lo que para nosotras son los elementos básicos de las filosofías y teorías de Watson, Parse y Benner, que nos permiten el análisis complejo de las situaciones de cuidados y la comprensión del juicio clínico, que emerge de la práctica como acontecimiento real. El paradigma de la complejidad nos lleva a prácticas responsables, a estar no en objetivos, sino en procesos, no en partes o en todos sino en individuos que son a la vez sujeto-objeto.The need to find the meaning of nursing activity independently of specialties, cultures, tasks, functions or competences, leads us to the usage of theories and concepts of analysis than can be applied in each situation, as a guide for the right nursing activity. Nursing philosophies and models provide us elements of reflection, creating doubts in relation to the practice, and once they are assumed, we recognize ourselves on them, helping us to the interpretation of the person-situation caring, carrying nursing to its matures side, validating Nigthingale's model. This work has the aim of implanting the basic elements of Watson, Parse and Benner's theories in order to analyze situations of caring and understand the clinical judgment emerging from the practice. The

  5. Estándares de calidad en los ensayos clínicos: ISO 9001-Buena Práctica Clínica Quality standards in clinical tests. ISO 9001: Good Clinical Practice

    Directory of Open Access Journals (Sweden)

    Sandra Álvarez Guerra

    2005-12-01

    Full Text Available La calidad en los ensayos clínicos conducidos por los centros de investigación por contrato , constituye un factor de suma importancia. En la actualidad estas instituciones usan como estándar de calidad la Buena Práctica Clínica. Sin embargo, su combinación con la Norma ISO 9001:2000, estándar de calidad, internacionalmente utilizado, no se ha generalizado. Para demostrar la factibilidad que el uso conjunto de estas normas brindan a las organizaciones se decidió establecer reflexiones para demostrar cómo se complementan ambos estándares de calidad en la realización de ensayos clínicos. Para esto se revisó bibliografía actualizada en dichos temas. Se valoraron aspectos en común como: clientes, responsabilidad, tratamiento de datos generados, estadística, control de la calidad y documentos esenciales. Por medio de estos aspectos ambas normas tributan a la calidad del ensayo clínico, para una mejor protección al paciente, resultados confiables, satisfacción de los clientes, internos y externos, que garanticen la mejora continua, y establecer planes de contingencia y medidas preventivas. Se concluye que ambas normativas no están en contraposición y pueden ser utilizadas como vía capaz de garantizar excelencia en el servicio brindado.The quality of clinical tests conducted by the research centers on contract is a very important factor. Nowadays, these institutions use Good Clinical Practice as the quality standard. However, the combination of the latter with internationally used ISO 9001:2000 quality standard has not yet been generalized. In order to prove the feasibility that the joint use of these standards offers to organizations, it was decided to reflect on the way both quality standards complement each other in the performance of clinical tests. To this end, updated literature review was made. Common aspects such as clients, responsibility, treatment of data, statistics, quality control and essential documents were

  6. Uso de los servicios de salud reproductiva por varones de dos ciudades argentinas

    Directory of Open Access Journals (Sweden)

    Edith Alejandra Pantelides

    2009-01-01

    Full Text Available El propósito de este trabajo es investigar el conocimiento de la existencia de servicios de salud para la cobertura de necesidades específicas de salud sexual y reproductiva y su utilización, por parte de varones adultos residentes en dos ciudades de distinto tamaño y características (Rosario y Reconquista, en la provincia de Santa Fe, Argentina. Los aspectos de salud sexual y reproductiva considerados fueron: prevención del embarazo, enfermedades de transmisión sexual, infertilidad y disfunciones sexuales; y para utilización de los servicios se consideraron: la búsqueda de información, de consejería, de provisión de métodos anticonceptivos, de diagnóstico y de tratamiento.

  7. Rosa dos Ventos em Nova Edição / Rosa dos Ventos New Edition

    Directory of Open Access Journals (Sweden)

    Susana de Araujo Gastal

    2015-07-01

    Full Text Available Revistas acadêmicas, como a nossa Rosa dos Ventos – Turismo e Hospitalidade, têm papel muito importante na difusão do conhecimento produzido na Universidade, em especial no momento brasileiro atual, quando diferentes Programas de Pós-Graduação de Turismo, Hospitalidades e áreas afins, consolidam suas investigações tanto nos mestrados como nos doutorados. Mas, acredito que há um papel ainda mais importante a ser desempenhado pelos nossos periódicos, qual seja, o de fomentar a discussão em torno dos temas pesquisados e sobre os resultados alcançados nesses processos. Tomara, essa discussão se expanda e deixe de envolver apenas autores e pareceristas, para criar um bom debate público com réplicas e tréplicas, pois a maturidade acadêmica passa por tais caminhos e suas veredas. Palavras-chave: Periódico Científico. Rosa dos Ventos – Turismo e Hospitalidade. Editorial. Academic journals, as Rosa dos Ventos - Tourism and Hospitality, play a very important role spreading the knowledge produced in the University, especially in the current Brazilian time when different Postgraduate Programs in Tourism, Hospitalities and related fields, consolidate investigations both, in masters and doctoral degrees. But I believe there is an even more important role to be performed by the journals, which is to increase discussion of topics surveyed and the results achieved in these process. Hopefully, this discussion will expand to the point where involve more than just authors and reviewers, creating a good public debate, because the academic maturity goes through such ways. . Keywords: Journal. Rosa dos Ventos – Tourism and Hospitality. Editorial.  

  8. Low-valent iron: an Fe(I) ate compound as a building block for a linear trinuclear Fe cluster

    NARCIS (Netherlands)

    Lichtenberg, C.; Viciu, L.; Vogt, M.; Rodríguez-Lugo, R.E.; Adelhardt, M.; Sutter, J.; Khusniyarov, M.M.; Meyer, K.; de Bruin, B.; Bill, E.; Grützmacher, H.

    2015-01-01

    A low-valent trinuclear iron complex with an unusual linear Fe(I)-Fe(II)-Fe(I) unit is presented. It is accessed in a rational approach using a salt metathesis reaction between a new anionic Fe(I) containing heterocycle and FeCl2. Its electronic structure was studied by single crystal XRD analysis,

  9. Ab initio study of (Fe, Ni) doped GaAs: Magnetic, electronic properties and Faraday rotation

    Science.gov (United States)

    Sbai, Y.; Ait Raiss, A.; Bahmad, L.; Benyoussef, A.

    2017-06-01

    The interesting diluted magnetic semiconductor (DMS), Gallium Arsenide (GaAs), was doped with the transition metals magnetic impurities: iron (Fe) and Nickel (Ni), in one hand to study the magnetic and magneto-optical properties of the material Ga(Fe, Ni) As, in the other hand to investigate the effect of the doping on the properties of this material, the calculations were performed within the spin polarized density functional theory (DFT) and generalized gradient approximation (GGA) with AKAI KKR-CPA method, the density of states (DOS) for different doping concentrations were calculated, giving the electronical properties, as well as the magnetic state and magnetic states energy, also the effect of these magnetic impurities on the Faraday rotation as magneto-optical property. Furthermore, we found the stable magnetic state for our doped material GaAs.

  10. Metal insulator transition in FeWN2: DFT and DFT+U study

    Science.gov (United States)

    Messiad, Meriem; Zanat, Kamel; Hamidani, Ali

    2017-11-01

    We have studied the electronic and magnetic properties of layered ternary transition metal nitrides, FeWN2. We found that the density functional theory (DFT) based approaches within the generalized gradient approximation frameworks fail to predict the correct ground state configuration. While the DFT plus on-site repulsion U method (DFT+U) predict the AF ordering which it's in good agreement with experiment. We found that the metal-insulator transition is accompanied by a magnetic phase transition which occurred at the same time, a ferromagnetic-metallic to antiferromagnetic-insulating transition where Ueff = 3eV . It is shown also that magnetism and correlation effects are important in band-gap formation in this compound. Our calculated results by DFT-mBJ show the same trend of the band gap. The fully spin polarized DOS at the Fermi level in FM phase makes from FeWN2 a promising candidate material for spintronic applications.

  11. Origin of magnetostriction in Fe-Ga

    DEFF Research Database (Denmark)

    Mudivarthi, Chaitanya; Laver, Mark; Cullen, James

    2010-01-01

    This paper investigates the origin of large magnetostriction in Fe-Ga alloys using small-angle neutron scattering (SANS) and Kerr microscopy. The SANS data for a single-crystal, electron irradiated, and quenched Fe81Ga19 sample under externally applied magnetic and elastic fields revealed...

  12. Electronic structure of Fe-based superconductors

    Indian Academy of Sciences (India)

    Abstract. Fe-based superconductors have drawn much attention during the last decade due to the presence of superconductivity in materials containing the magnetic element, Fe, and the coexistence of superconductivity and magnetism. Extensive study of the electronic structure of these systems suggested the dominant ...

  13. Electronic structure of Fe-based superconductors

    Indian Academy of Sciences (India)

    2015-05-29

    May 29, 2015 ... Fe-based superconductors have drawn much attention during the last decade due to the presence of superconductivity in materials containing the magnetic element, Fe, and the coexistence of superconductivity and magnetism. Extensive study of the electronic structure of these systems suggested the ...

  14. Structural and magnetic properties of Ce/Fe and Ce/FeCoV multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Tixier, S.; Boeni, P. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Mannix, D.; Stirling, W.G. [Liverpool Univ. (United Kingdom); Lander, G.H.

    1997-09-01

    Ce/Fe and Ce/FeCoV multilayers have been grown by magnetron sputtering. The interfaces are well defined and the layers are crystalline down to an individual layer thickness of 20 A. Ce/FeCoV multilayers show sharper interfaces than Ce/Fe but some loss of crystallinity is observed. Hysteresis loops obtained by SQUID show different behaviour of the bulk magnetisation as a function of the layer thickness. Fe moments are found by Moessbauer spectroscopy to be perpendicular to the interfaces for multilayers with small periodicity. (author) 2 figs., 2 refs.

  15. Calculated oscillation periods of the interlayer coupling in Fe/Cr/Fe and Fe/Mo/Fe sandwiches

    DEFF Research Database (Denmark)

    Mirbt, S.; Niklasson, A.M.N.; Johansson, B.

    1996-01-01

    We have performed an ab initio study of the oscillation periods of the interlayer coupling in sandwiches of [100] layers of body centered cubic Cr, respectively, Mo, with up to 20 monolayers thickness embedded in an Fe host. Our derived values for the oscillation periods of the interlayer coupling...... agree well with those expected from the respective Fermi surface calipers and are in excellent agreement with experiment. We compare the interlayer coupling across a nonenhanced paramagnetic Cr spacer with the interlayer coupling across a Cr spacer in the spin-density wave;state. We find that the spin......-density wave gives rise to an additional contribution to the interlayer coupling. The origin of the observed and calculated 18 Angstrom period of the interlayer coupling can be explained as due to a caliper of the Fermi surface of Cr in the CsCl structure. In the case of the Mo spacer we investigate...

  16. Contabilidade criativa e responsabilidade dos auditores

    Directory of Open Access Journals (Sweden)

    Ariovaldo dos Santos

    2003-08-01

    Full Text Available Nos contextos nacional e internacional da profissão contábil, o auditor tem exercido um papel fundamental. A atividade profissional do auditor independente tem ajudado a impulsionar o desenvolvimento dos mercados, além de contribuir para o estabelecimento da ordem socioeconômica mundial. Na visão dos usuários externos da informação contábil, e dos próprios clientes, a atuação do auditor é sinônimo de confiança e credibilidade. Nos últimos meses, a onda de escândalos contábeis, com grandes empresas de auditoria envolvidas, e até sentenciadas (no caso Enron, a Andersen foi considerada culpada, por um Júri de Houston - Texas, pela destruição de documentos, marcou a atividade profissional dos auditores e parece ter mudado a visão de responsabilidade desses profissionais sobre esses fatos. No presente artigo são estudados e apresentados alguns conceitos fundamentais relacionados com o fenômeno da contabilidade criativa, assim como os fatores que induzem sua utilização, dentre os quais pode-se destacar: valores éticos, morais e vácuos ou flexibilidade normativa. Tais fatores acabam por funcionar como catalisadores da engenharia contábil no desenho das demonstrações contábeis e passam a atender os interesses de quem as elabora em vez de buscar a imagem fidedigna do patrimônio.In the national and international contexts of professional accounting, the auditor has played a fundamental role. The professional activity of the independent auditor has both helped to encourage market development and contributed to the establishment of a global socio-economic order.From the point of view of the external users of accounting information and the clients themselves, the professional activity of the auditor is a synonym of trust and credibility. In the last few months, the wave of financial scandals involving large auditing companies, some of which were even convicted for their demonstrated - direct and indirect - intervention in

  17. Caracterización de propóleos provenientes del municipio de Caldas obtenido por dos métodos de recolección

    Directory of Open Access Journals (Sweden)

    Julián Martínez G.

    2012-04-01

    Full Text Available Objetivo. Determinar las características fisicoquímicas y la actividad antimicrobiana de propóleos de Apis mellifera, provenientes del municipio de Caldas, obtenidos por dos métodos de recolección. Materiales y métodos. Se utilizaron dos métodos de recolección: de raspado y trampa plastica. Se estableció el contenido de cera, ceniza, material insoluble y resina de los propóleos crudos. Al extracto etanólico de los propóleos se les determinó el perfil cromatográfico (GC-MS y el espectro UV; además, se evaluó la actividad antimicrobiana in vitro frente a hongos (Aspergillus sp., Penicillium sp., Colletotrichum acutatum y C. gloesporioides, y bacterias (Salmonella tiphy, Bacillus subtilis, Staphylococcus aureus y Escherichia coli. Resultados. El material obtenido mediante malla matrizada presentó un perfil químico amplio, buena actividad antimicrobiana y mejores parámetros de calidad, de acuerdo con estándares establecidos por normas internacionales que los propóleos obtenidos por el método de raspado. Además, pudo observarse que la acción antimicrobiana de los propóleos fue dependiente de la concentración del extracto y del hongo o bacteria evaluada. Conclusiones. La composición química y la actividad antibacteriana y antifúngica de los propóleos están relacionadas con el método de recolección. El presente estudio aporta información para la selección de la técnica de cosecha del propóleo de acuerdo con la aplicación que se desee dar.

  18. Evaluación de dos métodos para la separación de RNA mensajero de Plasmodium falciparum

    Directory of Open Access Journals (Sweden)

    Heidy Y. Guerrero

    1998-03-01

    Full Text Available En muchos casos, el estudio de la regulación de la expresión de genes específicos, requiere el aislamiento de su RNA mensajero (mRNA a partir del RNA total presente en la célula. Con el fin de garantizar la presencia de secuencias que se expresan en baja abundancia, es indispensable obtener preparaciones de mRNA que sean representativas de la población de mensajeros del organismo en estudio. En este trabajo se evaluó el rendimiento del mRNA de Plasmodium falciparum obtenido por dos métodos: cromatografía de afinidad en columnas de oligo dT celulosa y captura del mRNA por hibridización en solución con un primeroligo dT. Con los dos métodos, se obtuvieron rendimientos similares en un rango entre 0,7 y 1,1% con respecto al RNA total de partida. El tamaño del cDNA sintetizado a partir de mensajeros separados por cromatografía fue de 0,4 a 4 Kb, mientras que los provenientes del método de captura, permitieron un rango entre 0,4 y 8 Kb. Este hecho sugiere las mejores posibilidades que ofrece el método de captura para obtener poblaciones de mensajeros con mayores tamaños, si se compara con el método tradicional. La presencia de clones con genes de copia única como son los de tubulina, actina II, miosina, calmodulina, glucosa fosfato-isomerasa y glucosa-fosfato-deshidrogenasa, en genotecas de cDNA, permiten inferir una buena representatividad de las secuencias expresadas en la preparación de mRNA.

  19. Magnetic studies of Fe/Cu multilayers

    Energy Technology Data Exchange (ETDEWEB)

    El Khiraoui, S. [Laboratoire de Physique et Mecanique des Materiaux, Universite Sultan Moulay Slimane, FST de Beni-Mellal, B.P. 523, 23000 Beni-Mellal (Morocco); Sajieddine, M. [Laboratoire de Physique et Mecanique des Materiaux, Universite Sultan Moulay Slimane, FST de Beni-Mellal, B.P. 523, 23000 Beni-Mellal (Morocco)], E-mail: sajieddinem@yahoo.fr; Hehn, M.; Robert, S.; Lenoble, O.; Bellouard, C. [Laboratoire de Physique des Materiaux, UMR-CNRS 7556, B.P. 239, 54506 Vandoeuvre-les-Nancy Cedex (France); Sahlaoui, M. [Laboratoire de Physique et Mecanique des Materiaux, Universite Sultan Moulay Slimane, FST de Beni-Mellal, B.P. 523, 23000 Beni-Mellal (Morocco); Benkirane, K. [Laboratoire des Materiaux, Micro-electronique, Automatique et Thermique, Faculte des Sciences Ain-Chock, Universite Hassan II, B.P. 5366 Maarif, Casablanca (Morocco)

    2008-07-01

    The structural and magnetic properties of sputtered Fe/Cu multilayers are examined as a function of Fe layer thickness t{sub Fe} by means of X-ray diffraction, Moessbauer spectrometry and superconducting quantum interference magnetometer. The temperature dependence of the spontaneous magnetization M(T) is well described by a T{sup 3/2} law in all multilayers in the temperature range 5-300 K. The interface anisotropy constant of Fe/Cu multilayers, K{sub s}, is found to be 0.31 and 0.45 erg/cm{sup 2} at 5 and 300 K, respectively. A spin-wave theory has been used to explain the temperature dependence of the magnetization and the approximate values for the bulk exchange interaction J{sub b}, surface exchange interaction J{sub s} and the interlayer coupling strength J{sub I} for various Fe layer thicknesses have been obtained.

  20. In-Vivo Gene Signatures of Mycobacterium tuberculosis in C3HeB/FeJ Mice

    Science.gov (United States)

    Gautam, Uma Shankar; Mehra, Smriti; Kaushal, Deepak

    2015-01-01

    Despite considerable progress in understanding the pathogenesis of Mycobacterium tuberculosis (Mtb), development of new therapeutics and vaccines against it has proven difficult. This is at least in part due to the use of less than optimal models of in-vivo Mtb infection, which has precluded a study of the physiology of the pathogen in niches where it actually persists. C3HeB/FeJ (Kramnik) mice develop human-like lesions when experimentally infected with Mtb and thus make available, a faithful and highly tractable system to study the physiology of the pathogen in-vivo. We compared the transcriptomics of Mtb and various mutants in the DosR (DevR) regulon derived from Kramnik mouse granulomas to those cultured in-vitro. We recently showed that mutant ΔdosS is attenuated in C3HeB/FeJ mice. Aerosol exposure of mice with the mutant mycobacteria resulted in a substantially different and a relatively weaker transcriptional response (Mtb:ΔdosR; ‘Lipid Metabolism’ in Mtb:ΔdosT; ‘Virulence, Detoxification, Adaptation’ in both Mtb:ΔdosR and Mtb:ΔdosT; and ‘PE/PPE’ family in all mutant strains compare to wild-type Mtb H37Rv, suggesting that the inability to induce DosR functions to different levels can modulate the interaction of the pathogen with the host. The Mtb genes expressed during growth in C3HeB/FeJ mice appear to reflect adaptation to differential nutrient utilization for survival in mouse lungs. The genes such as glnB, Rv0744c, Rv3281, sdhD/B, mce4A, dctA etc. downregulated in mutant ΔdosS indicate their requirement for bacterial growth and flow of carbon/energy source from host cells. We conclude that genes expressed in Mtb during in-vivo chronic phase of infection in Kramnik mice mainly contribute to growth, cell wall processes, lipid metabolism, and virulence. PMID:26270051

  1. La larga vida de dos rocas orensanas

    Directory of Open Access Journals (Sweden)

    García Quintela, Marco V.

    2011-12-01

    Full Text Available We study two rocks, a rock carving and a «rocky sanctuary » from the Ourense province (Spain, with two complementary methodologies, landscape archeology and «biography» (Kopytoff of objects. We start with their description in Christian texts, and then we observe that their relation with important hillforts forms a localization pattern, and finally we propose to date that relationship in the Iron Age. This chronology of the rocks and the following Christian reevaluation leads towards their «social life». These analyses are pertinent in the current debate about the chronology of the Galician rock art, and we propose that the use and meaning in the long term is as important as the initial moment of the carving.Se estudian dos rocas, un petroglifo y un «santuario rupestre » de la provincia de Ourense, con dos metodologías complementarias, la arqueología del paisaje y la «biografía» (Kopytoff de los objetos. Partiendo de su descripción en textos cristianos se considera el patrón de localización que conforman en relación con castros importantes, relación que se propone fechar en la Edad del Hierro. Esta adscripción cronocultural y su posterior resemantización cristiana lleva a la consideración de su «vida social». Estas aproximaciones inciden en el debate sobre la datación del arte rupestre en Galicia y se propone que, más allá del momento de grabado inicial, se estudie su uso y sentido en la larga duración.

  2. Tuning exchange bias in core/shell FeO/Fe3O4 nanoparticles.

    Science.gov (United States)

    Sun, Xiaolian; Huls, Natalie Frey; Sigdel, Aruna; Sun, Shouheng

    2012-01-11

    Monodisperse 35 nm FeO nanoparticles (NPs) were synthesized and oxidized in a dry air atmosphere into core/shell FeO/Fe(3)O(4) NPs with both FeO core and Fe(3)O(4) shell dimensions controlled by reaction temperature and time. Temperature-dependent magnetic properties were studied on FeO/Fe(3)O(4) NPs obtained from the FeO NPs oxidized at 60 and 100 °C for 30 min. A large exchange bias (shift in the hysteresis loop) was observed in these core/shell NPs. The relative dimensions of the core and shell determine not only the coercivity and exchange field but also the dominant reversal mechanism of the ferrimagnetic Fe(3)O(4) component. This is the first time demonstration of tuning exchange bias and of controlling asymmetric magnetization reversal in FeO/Fe(3)O(4) NPs with antiferromagnetic core and ferrimagnetic shell. © 2011 American Chemical Society

  3. Connecting observations of hematite (alpha-Fe2O3) growth catalyzed by Fe(II).

    Science.gov (United States)

    Rosso, Kevin M; Yanina, Svetlana V; Gorski, Christopher A; Larese-Casanova, Philip; Scherer, Michelle M

    2010-01-01

    Electron exchange between aqueous Fe(II) and structural Fe(III) in iron oxides and oxyhydroxides is important for understanding degradation of environmental pollutants through its apparent constitutive role underlying highly reactive "sorbed Fe(II)" and by catalyzing phase interconversion among these minerals. Although a mechanistic understanding of relationships between interfacial Fe(II)(ads)-Fe(III)(oxide) electron transfer, bulk electron conduction, Fe(II) release, and phase transformation behavior is emerging, much remains unclear, in part due to poorly interconnected investigations. The focus of this study is on reconciling two mutually similar observations of Fe(II)-catalyzed hematite growth documented spectroscopically and microscopically under substantially different chemical conditions. Here, we employ iron isotopic labeling to demonstrate that hematite grown on the (001) surface in Fe(II)-oxalate solution at pH 2.10 and 348 K has magnetic properties that closely correspond to those of hematite grown in Fe(II) solution at pH 7.4 and room temperature. The temperature evolution and extent of the Morin transition displayed in these two materials strongly suggest a mechanistic link involving trace structural Fe(II) incorporation into the growing hematite. Our findings indicate that Fe(II) catalyzed growth of hematite on hematite can occur under environmentally relevant conditions and may be due to bulk electron conduction previously demonstrated for hematite single crystals.

  4. Hybrid materials based on polymethylsilsesquioxanes containing Fe, Pt, and Fe-Pt metallic nanoparticles

    Science.gov (United States)

    Vasil'kov, A. Yu.; Migulin, D. A.; Naumkin, A. V.; Zubavichus, Ya. V.; Budnikov, A. V.; Ellert, O. G.; Maksimov, Yu. V.; Muzafarov, A. M.

    2017-11-01

    New hybrid materials based on Pt, Fe, and Pt-Fe nanoparticles stabilized in a matrix of polymethylsilsesquioxane nanogel and ultrahigh molecular weight polyethylene (UHMWPE) were prepared. Metal vapor synthesis was used to produce mono- and bimetallic nanoparticles. It was shown that organosilicon nanogel effectively stabilizes Pt nanoparticles with an average size of 0.9 nm. Using the nanogel results in the formation of superparamagnetic Fe particles 3-5 nm in size that consist of ferromagnetic Fe0 core and antiferromagnetic shells of Fe oxides. It is established that using an organosilicon matrix in the formation of Pt-Fe/UHMWPE systems helps reduce the average particle size of Fe in the material from 6.5 to 4.5 nm and narrow their particle size distribution. The composition, magnetic and electronic characteristics of the nanocomposites are studied via transmission electron microscopy, X-ray photoelectron spectroscopy, Mössbauer spectroscopy, XANES, and EXAFS.

  5. Comparación de las prácticas de cuidado en dos grupos de gestantes en la ciudad de Sincelejo

    Directory of Open Access Journals (Sweden)

    LUZ MARINA GARCÍA GARCÍA

    2008-07-01

    Full Text Available Para comparar las prácticas de cuidado que realizan consigo mismas y con su hijo por nacer un grupo de gestantes adolescentes y otro grupo de gestantes adultas que asisten a control prenatal en Sincelejo, durante los meses de julio y septiembre de 2006, se desarrolló un estudio descriptivo, cuantitativo y transversal, con una muestra de 97 gestantes adolescentes entre 15 y 19 años y de 153 gestantes adultas entre 20 y 45 años, sin patologías asociadas, a quienes se les aplicó un instrumento sobre prácticas de cuidado, validado por la Universidad Nacional de Colombia, sede Bogotá. Estas prácticas se clasificaron en buenas, regulares y malas, en los dos grupos, para establecer la comparación cuantitativa de las mismas. Los principales resultados fueron: diferencias estadísticamente significativas en las dimensiones de estimulación prenatal, higiene y cuidados personales, alimentación y sustancias no beneficiosas; en estas cuatro dimensiones el resultado de buenas prácticas fue más favorable para las gestantes adultas; no se encontró diferencia significativa en las dimensiones de ejercicio y descanso, y sistemas de apoyo. La mayoría de las gestantes adultas (81,7% realizaban actividades domésticas que les producían cansancio; 23,53% no desarrollaban actividades recreativas; 25,77% de las gestantes adolescentes y 41,18% de las gestantes adultas consumían lácteos. 19,59% de las gestantes adolescentes y 6,54% de las adultas no evitaban el consumo de licor y 4,12% de las gestantes adolescentesy0,65% de lasgestantes adultas habían consumido sustancias psicoactivas. Tanto adolescentes (68,04% como adultas (52,29% realizaban prácticas de estimulación prenatal catalogadas como regulares. Solo 31,37% de las gestantes adultas y 21,65% de las gestantes adolescentes tenían prácticas adecuadas de estimulación prenatal.

  6. Hyperfine fields of Fe in Nd2Fe14BandSm2Fe17N3

    Science.gov (United States)

    Akai, Hisazumi; Ogura, Masako

    2015-03-01

    High saturation magnetization of rare-earth magnets originates from Fe and the strong magnetic anisotropy stems from f-states of rare-earth elements such as Nd and Sm. Therefore the hyperfine fields of both Fe and rare-earth provide us with important pieces of information: Fe NMR enable us to detect site dependence of the local magnetic moment and magnetic anisotropy (Fe sites also contribute to the magnetic anisotropy) while rare-earth NQR directly give the information of electric field gradients (EFG) that are related to the shape of the f-electron cloud as well as the EFG produced by ligands. In this study we focus on the hyperfine fields of materials used as permanent magnets, Nd2Fe14BandSm2Fe17N3 from theoretical points of view. The detailed electronic structure together with the hyperfine interactions are discussed on the basis of the first-principles calculation. In particular, the relations between the observed hyperfine fields and the magnetic properties are studies in detail. The effects of doping of those materials by other elements such as Dy and the effects of N adding in Sm2Fe17N3 will be discussed. This work was supported by Elements Strategy Initiative Center for Magnetic Materials Project, the Ministry of Education, Culture, Sports, Science and Technology, Japan.

  7. A method for determination of [Fe3+]/[Fe2+] ratio in superparamagnetic iron oxide

    Science.gov (United States)

    Jiang, Changzhao; Yang, Siyu; Gan, Neng; Pan, Hongchun; Liu, Hong

    2017-10-01

    Superparamagnetic iron oxide nanoparticles (SPION), as a kind of nanophase materials, are widely used in biomedical application, such as magnetic resonance imaging (MRI), drug delivery, and magnetic field assisted therapy. The magnetic property of SPION has close connection with its crystal structure, namely it is related to the ratio of Fe3+ and Fe2+ which form the SPION. So a simple way to determine the content of the Fe3+ and Fe2+ is important for researching the property of SPION. This review covers a method for determination of the Fe3+ and Fe2+ ratio in SPION by UV-vis spectrophotometry based the reaction of Fe2+ and 1,10-phenanthroline. The standard curve of Fe with R2 = 0.9999 is used for determination the content of Fe2+ and total iron with 2.5 mL 0.01% (w/v) SPION digested by HCl, pH = 4.30 HOAc-NaAc buffer 10 mL, 0.01% (w/v) 1,10-phenanthroline 5 mL and 10% (w/v) ascorbic acid 1 mL for total iron determine independently. But the presence of Fe3+ interfere with obtaining the actual value of Fe2+ (the error close to 9%). We designed a calibration curve to eliminate the error by devising a series of solution of different ratio of [Fe3+]/[Fe2+], and obtain the calibration curve. Through the calibration curve, the error between the measured value and the actual value can be reduced to 0.4%. The R2 of linearity of the method is 0.99441 and 0.99929 for Fe2+ and total iron respectively. The error of accuracy of recovery and precision of inter-day and intra-day are both lower than 2%, which can prove the reliability of the determination method.

  8. Estudio Estadístico Comparativo sobre Dos Variedades de Maíz

    Directory of Open Access Journals (Sweden)

    Ramírez Hernán

    1946-12-01

    Full Text Available 1°-Se determinó el porcentaje de granos en mazorcas de tipo comercial para dos variedades de maíz. Una seleccionada en Venezuela con la denominación de "Venezuela-l" de gran adaptación y buena aceptación entre nuestros agricultores, y otra variedad de maíz criollo distinguido en el comercio con el nombre de "Cuba Blanco" con los siguientes resultados en promedio: Para Venezuela-l 81.29% Para el Cuba blanco 80.90 % 2°-Estas dos variedades se compararon por los diversos caracteres de la mazorca: número de surcos, peso en gramos, largo en centímetros, diámetro en milímetros; de la tusa: diámetro en milímetros y peso en gramos, y de los granos: porcentaje, peso en gramos y profundidad en milímetros. El resultado obtenido fue muy favorable para el Venezuela-l, lo cual confirma los buenos efectos de la selección aplicada al maíz. 3°-Un estudio de correlación simple, correlación parcial y regresión parcial aplicado a varios caracteres de la mazorca en las mismas variedades mostró un alto grado de relación entre caracteres, como peso total y largo; peso total y diámetro; peso total y profundidad de los granos; número de surcos y diámetro; largo y diámetro y diámetro y profundidad de los granos. Así mismo, al hacer constantes, la influencia del porcentaje de granos y surcos, se obtuvo una alta significación para la relación entre el peso total y el largo; el caso recíproco al hacer constante la influencia del porcentaje de granos y surcos se obtuvo una alta significación entre el largo y el peso total; también resultó altamente significativa la relación entre el peso total y el porcentaje de granos cuando se tomaron el número de surcos y el largo como constantes. Se determinó el coeficiente de regresión parcial para valorar la influencia que tiene un carácter que se toma como independiente sobre otro tomado como dependiente, resultando una influencia mayor de aquellos caracteres sobre éstos en

  9. Magnetic nanowires (Fe, Fe-Co, Fe-Ni – magnetic moment reorientation in respect of wires composition

    Directory of Open Access Journals (Sweden)

    Kalska-Szostko Beata

    2015-03-01

    Full Text Available Magnetic nanowires of Fe, Fe-Co, and Fe-Ni alloy and layered structure were prepared by electrochemical alternating current (AC deposition method. The morphology of the nanowires in and without the matrix was studied by energy dispersive X-ray spectroscopy (EDX, scanning electron microscopy (SEM, and X-ray diffraction (XRD, respectively. The wires either show strong dependence on the combination of elements deposition (alloy or layered or chemical composition (Co or Ni. The magnetic properties of the nanostructures were determined on the basis of Mössbauer spectroscopy (MS.

  10. Neurobiologia dos transtornos do controle dos impulsos The neurobiology of impulse control disorders

    Directory of Open Access Journals (Sweden)

    Wendol A Williams

    2008-05-01

    Full Text Available OBJETIVO: Revisar os artigos sobre substratos neurobiológicos dos transtornos do controle dos impulsos. O jogo patológico é o foco central desta revisão na medida em que a maioria dos estudos biológicos dos formalmente classificados como transtornos do controle dos impulsos examinou este transtorno. MÉTODO: Foi feita uma busca no banco de dados Medline de artigos publicados de 1966 até o presente para identificar aqueles relevantes para serem revisados neste artigo. DESFECHOS: Estudos pré-clínicos sugerem que a neuromodulação das monoaminas cerebrais está associada à tomada de decisões impulsivas e aos comportamentos de risco. Os estudos clínicos implicam diversos sistemas de neurotransmissores (serotoninérgico, dopaminérgico, adrenérgico e opióide na fisiopatologia do jogo patológico e de outros transtornos do controle dos impulsos. Estudos de neuroimagem preliminares têm indicado o córtex pré-frontal ventromedial e o estriato ventral como atuantes na fisiopatologia do jogo patológico e de outros transtornos do controle dos impulsos. As contribuições genéticas para o jogo patológico parecem substanciais e os estudos iniciais têm relacionado esse transtorno a polimorfismos alélicos específicos, ainda que os achados de varredura genômica ainda tenham que ser publicados. CONCLUSÃO: Mesmo que tenham sido logrados avanços significativos em nossa compreensão sobre os transtornos do controle dos impulsos, mais pesquisas são necessárias para ampliar o conhecimento existente e traduzir esses achados em avanços clínicos.OBJECTIVE: To review the neurobiological substrates of impulse control disorders. Pathological gambling is a main focus of the review in that most biological studies of the formal impulse control disorders have examined this disorder. METHOD: The medical database Medline from 1966 to present was searched to identify relevant articles that were subsequently reviewed to generate this manuscript

  11. Guia de campo dos cetáceos dos Açores

    OpenAIRE

    Fernandez, Marc; Faria, João; Cravinho, Miguel; Ana I. Neto; Azevedo, José M. N.

    2016-01-01

    Os Cetáceos (baleias e golfinhos) são um dos 5 grupos de mamíferos marinhos, juntamente com os pinípedes (focas, otárias e morsas), os sirénios (manatins e dugongos), as lontras e os ursos polares. Evidências moleculares e fósseis sugerem que baleias e golfinhos incluem-se dentro dos artiodáctilos, o grupo de mamíferos com cascos em número par, e.g. porcos, vacas e hipopótamos. ABSTRACT: Cetaceans (whales, dolphins, and porpoises) are one of the 5 groups of marine mammals, which also inclu...

  12. Conteúdo de minerais dos ingredientes e da multimistura Mineral content of ingredients and multimixture

    Directory of Open Access Journals (Sweden)

    Celma de Oliveira Barbosa

    2006-12-01

    Full Text Available Os objetivos deste estudo foram determinar o conteúdo de minerais dos ingredientes e da multimistura, produzida e comercializada em Teresina-PI e avaliar a composição mineral da multimistura, relacionando-a com a ingestão diária recomendada (IDR. As amostras estudadas foram multimistura, pó da folha de macaxeira, farelo de arroz, farelo de trigo, farinha de trigo e fubá de milho. Os minerais Ca, Cu, K, Mn, Zn, Fe, Mg, Na e P foram determinados usando a técnica de espectrometria de emissão atômica com fonte de plasma indutivamente acoplado (ICP OES. A análise estatística dos dados foi realizada por meio de médias e desvios padrão. As amostras apresentaram baixos teores para a maioria dos minerais analisados, com exceção dos ingredientes farelo de trigo e farinha de trigo. Em especial, observou-se que a multimistura não atingiu o mínimo necessário de 25% do valor diário (VD, para ser considerada complemento nutricional pelo Ministério da Saúde, para os minerais analisados, com exceção do Mn e Mg. Concluiu-se que não existe uma padronização nas quantidades dos ingredientes no preparo da multimistura e que os teores dos minerais não atendem às recomendações diárias necessárias para crianças.The objectives of this study were to determine the mineral content of ingredients and multimixture produced and commercialized in Teresina-PI/Brazil and evaluate the mineral composition in relation to the dietary reference intakes (DRI. The studied samples were multimixture, cassava leaf powder, rice bran, wheat bran, wheat flour and corn flour. The minerals Ca, Cu, K, Mn, Zn, Fe, Mg, Na and P were determined using the atomic emission spectrometry (ICP OES. The statistics analysis of the data was carried out by mean and standard deviations. The samples had low levels in most of the analyzed minerals, except for wheat bran and wheat flour. In particular, it was observed that the multimixture did not reach the minimum of 25% of the

  13. Ordering phenomena in FeCo-films and Fe/Cr-multilayers: an X-ray and neutron scattering study

    Energy Technology Data Exchange (ETDEWEB)

    Nickel, B.

    2001-07-01

    The following topics are covered: critical phenomena in thin films, critical adsorption, finite size scaling, FeCo Ising model, kinematical scattering theory for thin films, FeCo thin films, growth and characterisation of single crystal FeCo thin films, X-ray study of ordering in FeCo films, antiferromagnetic coupling in Fe/Cr multilayers, neutron scattering on Fe/Cr multilayers (WL)

  14. Iron isotope fractionation during microbially stimulated Fe(II) oxidation and Fe(III) precipitation

    Science.gov (United States)

    Balci, N.; Bullen, T.D.; Witte-Lien, K.; Shanks, Wayne C.; Motelica, M.; Mandernack, K.W.

    2006-01-01

    Interpretation of the origins of iron-bearing minerals preserved in modern and ancient rocks based on measured iron isotope ratios depends on our ability to distinguish between biological and non-biological iron isotope fractionation processes. In this study, we compared 56Fe/54Fe ratios of coexisting aqueous iron (Fe(II)aq, Fe(III)aq) and iron oxyhydroxide precipitates (Fe(III)ppt) resulting from the oxidation of ferrous iron under experimental conditions at low pH (out using both pure cultures of Acidothiobacillus ferrooxidans and sterile controls to assess possible biological overprinting of non-biological fractionation, and both SO42- and Cl- salts as Fe(II) sources to determine possible ionic/speciation effects that may be associated with oxidation/precipitation reactions. In addition, a series of ferric iron precipitation experiments were performed at pH ranging from 1.9 to 3.5 to determine if different precipitation rates cause differences in the isotopic composition of the iron oxyhydroxides. During microbially stimulated Fe(II) oxidation in both the sulfate and chloride systems, 56Fe/54Fe ratios of residual Fe(II)aq sampled in a time series evolved along an apparent Rayleigh trend characterized by a fractionation factor ??Fe(III)aq-Fe(II)aq???1.0022. This fractionation factor was significantly less than that measured in our sterile control experiments (???1.0034) and that predicted for isotopic equilibrium between Fe(II)aq and Fe(III)aq (???1.0029), and thus might be interpreted to reflect a biological isotope effect. However, in our biological experiments the measured difference in 56Fe/54Fe ratios between Fe(III)aq, isolated as a solid by the addition of NaOH to the final solution at each time point under N2-atmosphere, and Fe(II)aq was in most cases and on average close to 2.9??? (??Fe(III)aq-Fe(II)aq ???1.0029), consistent with isotopic equilibrium between Fe(II)aq and Fe(III)aq. The ferric iron precipitation experiments revealed that 56Fe/54Fe ratios

  15. Tracing anthropogenic aerosol Fe sources in the North Atlantic Ocean using dissolved Fe isotope ratios

    Science.gov (United States)

    Conway, T. M.; Shelley, R.; Aguilar-Islas, A. M.; Landing, W. M.; Mahowald, N. M.; John, S.

    2016-02-01

    Supply of iron (Fe) to the surface ocean from atmospheric deposition plays a vital role in marine biogeochemical cycles, especially in Fe-limited areas or regions close to dust sources. However, large uncertainties remain over the fluxes, solubility and bioavailability of Fe supplied by aerosol dust. Additionally, aerosol Fe is likely to consist of a mixture of natural and anthropogenic (urban, biomass burning and combustion) components, which may have very different solubilities in seawater [e.g. 1]. To constrain soluble Fe supply to the oceans, it is thus vitally important to understand the relative contributions of different types of aerosol Fe, their solubilities and spatial distributions. Stable Fe isotopes (δ56Fe) may offer a way to discriminate between different dust sources [2], because of differential fractionation during a range of chemical processes. In this study, we measured δ56Fe in North Atlantic marine aerosols collected during two US GEOTRACES GA03 cruises (Lisbon to Woods Hole via Cape Verde, 2010-11) and we present δ56Fe measurements (relative to IRMM-014) from both the bulk aerosol (HF-HNO3 digested) and the water-soluble (10s ultrapure water leach) fractions. Aerosols collected from different air-masses (Saharan, European and N. American) allowed us to investigate the variability in δ56Fe due to different regional dust sources. The bulk phase was characterized by near-crustal δ56Fe values of +0.1±0.2‰, indicating the dominance of mineral dust. In contrast, the water-soluble fraction showed great variability; aerosols from European and North American air-masses were very isotopically light (-1.2±0.2‰ and -1.1±0.7‰) while those from Saharan air-masses were crustal (+0.1‰). Comparison of this data with isotope-informed model predictions of soluble Fe from mineral and anthropogenic sources (combustion, biofuels and biomass burning) [1], suggests that the data is consistent with mixing of either 1) Fe from mineral dust (+0.1‰) and

  16. AVALIAÇÃO DOS MÉTODOS DE ESTUDO DOS DISCENTES

    Directory of Open Access Journals (Sweden)

    Ryan Luiz da Silva Oliveira

    2017-05-01

    Full Text Available Este trabalho apresenta o resultado de uma pesquisa estatística realizada com 113 discentes oriundos de instituições de ensino públicas e privadas, com o objetivo de investigar os métodos e o tempo dedicado aos estudos. Onde 69% dos discentes estuda há um período de até dois anos em sua atual instituição de ensino. Do total de discentes, 46,9% dedicam de uma a três horas de seu dia para estudar, e desse total, 83,2% preferem estudar individualmente, devido a um melhor rendimento pessoal. Desses discentes, 69,9% se consideram iguais a seus demais colegas de classe, e que 13,3% são os que consideram estudar mais que seus colegas. Essa pesquisa traz o resultado de outras duas pesquisas, sendo uma do Instituto de Pesquisa Econômica Aplicada (Ipea e outra da Universidade Federal do Ceará (UFC, cujos resultados obtidos na avaliação dos métodos de estudo dos discentes, quando analisados com essas pesquisas, nos mostram que ambas apresentam resultados parecidos.

  17. Formulación de una propuesta para la aplicación del sistema de Buenas Prácticas de Manufactura (BPM), en la Empresa Lacto Ochoa Fernández Cía. Ltda., de la ciudad de Cañar

    OpenAIRE

    Ramos Ortega, Boris Francisco

    2016-01-01

    El documento consiste en una implementación de buenas prácticas de manufactura, el propósito es potenciar las ventas como también capacitar y concientizar al personal de la empresa sobre la importancia de este tema; con el fin de proponer este proyecto se genera como una necesidad realizar productos orientados en la normativa de calidad existente. The document consists of a manufacturing, implementation of good practices, the purpose is to boost sales as well as train and raise awareness a...

  18. Magnetic and structural properties of nitrided Fe and FeTi thin films

    CERN Document Server

    Bonder, M J

    2001-01-01

    presence of weak perpendicular anisotropy occurring as the bilayer thickness increased. As the bilayer thickness was increased there was an asymptotic approach of the magnetization to the level of the unexposed materials. The presence of the perpendicular anisotropy was maintained for a larger parameter space. In both series the anisotropy is attributed to stress induced by the substrate, Nitriding Fe and FeTi using the aforementioned technique provides a controlled and viable way to alter the magnetic and structural properties. This thesis investigates the magnetic and structural properties of Fe and Fe sub 8 sub 5 Ti sub 1 sub 5 thin films nitrided using a nitrogen atom source. In this novel technique, the atom source produces an atomic nitrogen beam for which multilayer samples with bilayers of the form Fe/FeN or FeTi/FeTiN were synthesized by varying the thickness of the Fe or FeTi exposed to the nitrogen beam. The samples studied here are all in the as-deposited state. X-Ray reflectivity confirms the pre...

  19. Strategies of aerobic microbial Fe acquisition from Fe-bearing montmorillonite clay

    Science.gov (United States)

    Kuhn, Keshia M.; DuBois, Jennifer L.; Maurice, Patricia A.

    2013-09-01

    This research investigated strategies used by the common aerobic soil bacterium Pseudomonas mendocina to acquire Fe associated with Fe(III)-bearing montmorillonite (MMT) clay. Given the known importance of Fe(III)-chelating siderophores, Fe-limited batch experiments were conducted using a wild-type (WT) strain that produces siderophores and a ΔpmhA mutant with a siderophore(-) phenotype. Growth measurements were coupled with a transcriptional biosensor assay that monitors the siderophore biosynthesis gene pmhA, measurements of cells' reducing ability, and quantification of exopolymeric substance (EPS) production. WT cells actively grow when MMT is the sole Fe source, but sorption to MMT may decrease the concentration of dissolved Fe-siderophore complex accessible to cells. Cells also obtain Fe by reducing MMT-associated Fe(III), but because P. mendocina lacks a secreted/diffusible reductant, direct physical contact is required. Dual strategies for Fe acquisition—a reducing mechanism that requires contact and that is likely facilitated by biofilm production and a siderophore related mechanism that does not require contact—provide flexibility to address the environmental Fe challenge.

  20. Probing outflows in z = 1 ∼ 2 galaxies through Fe II/Fe II* multiplets

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Yuping; Giavalisco, Mauro [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Guo, Yicheng [UCO/Lick Observatory, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Kurk, Jaron, E-mail: yupingt@astro.umass.edu [Max-Planck-Institut für Extraterrestrial Physik, Gießenbachstrasse, D-85748 Garching bei München (Germany)

    2014-10-01

    We report on a study of the 2300-2600 Å Fe II/Fe II* multiplets in the rest-UV spectra of star-forming galaxies at 1.0 < z < 2.6 as probes of galactic-scale outflows. We extracted a mass-limited sample of 97 galaxies at z ∼ 1.0-2.6 from ultra-deep spectra obtained during the GMASS spectroscopic survey in the GOODS South field with the Very Large Telescope and FORS2. We obtain robust measures of the rest equivalent width of the Fe II absorption lines down to a limit of W{sub r} > 1.5 Å and of the Fe II* emission lines to W{sub r} > 0.5 Å. Whenever we can measure the systemic redshift of the galaxies from the [O II] emission line, we find that both the Fe II and Mg II absorption lines are blueshifted, indicating that both species trace gaseous outflows. We also find, however, that the Fe II gas has generally lower outflow velocity relative to that of Mg II. We investigate the variation of Fe II line profiles as a function of the radiative transfer properties of the lines, and find that transitions with higher oscillator strengths are more blueshifted in terms of both line centroids and line wings. We discuss the possibility that Fe II lines are suppressed by stellar absorptions. The lower velocities of the Fe II lines relative to the Mg II doublet, as well as the absence of spatially extended Fe II* emission in two-dimensional stacked spectra, suggest that most clouds responsible for Fe II absorption lie close (3 ∼ 4 kpc) to the disks of galaxies. We show that the Fe II/Fe II* multiplets offer unique probes of the kinematic structure of galactic outflows.

  1. Electrodeposited NiCoFe films from electrolytes with different Fe ion concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Kockar, Hakan, E-mail: hkockar@balikesir.edu.tr [Balikesir Universitesi, Fen Edebiyat Fakultesi, Fizik Bolumu, Cagıs Yerleskesi, 10145 Balikesir (Turkey); Demirbas, Ozen, E-mail: ozendemirbas@hotmail.com [Balikesir Universitesi, Fen Edebiyat Fakultesi, Fizik Bolumu, Cagıs Yerleskesi, 10145 Balikesir (Turkey); Kuru, Hilal, E-mail: htopcu@balikesir.edu.tr [Balikesir Universitesi, Fen Edebiyat Fakultesi, Fizik Bolumu, Cagıs Yerleskesi, 10145 Balikesir (Turkey); Alper, Mursel, E-mail: malper@uludag.edu.tr [Uludag Universitesi, Fen Edebiyat Fakultesi, Fizik Bolumu, 16059 Gorukle, Bursa (Turkey); Karaagac, Oznur, E-mail: karaagac@balikesir.edu.tr [Balikesir Universitesi, Fen Edebiyat Fakultesi, Fizik Bolumu, Cagıs Yerleskesi, 10145 Balikesir (Turkey); Haciismailoglu, Murside, E-mail: msafak@uludag.edu.tr [Uludag Universitesi, Fen Edebiyat Fakultesi, Fizik Bolumu, 16059 Gorukle, Bursa (Turkey); Ozergin, Ercument, E-mail: ercumentz@yahoo.com [Balikesir Universitesi, Fen Edebiyat Fakultesi, Fizik Bolumu, Cagıs Yerleskesi, 10145 Balikesir (Turkey)

    2014-06-01

    Ternary NiCoFe films, relating their magnetic and magnetoresistance properties with film composition, and the corresponding crystal structure were investigated in terms of different Fe ion concentrations in the electrolyte. The current–time transients were recorded to control the growth of proper films. The film composition by energy dispersive X-ray spectroscopy revealed that as the Fe ion concentration in the electrolyte was increased, the Fe and Co contents in the films increased and Ni content decreased. From the structural analysis by X-ray diffraction, all films had a face-centred cubic structure and, no reflection from body-centred cubic (bcc) Fe was existed in all samples due to <12 at% Fe. The saturation magnetisation increased from 865 emu/cm{sup 3} to 1080 emu/cm{sup 3} and the coercivities decreased from 60 Oe to 13 Oe with increasing Fe and Co contents and decreasing Ni content in the films. All NiCoFe films showed anisotropic magnetoresistance. The longitudinal magnetoresistance magnitudes decreased from 6.3% to 2.2% with increasing Fe and Co contents and decreasing Ni in the films while the magnitudes of transverse magnetoresistance stayed almost constant at ∼5.0%. The variations in magnetic and magnetoresistive properties related to the crystal structure were attributed to the compositional changes caused by the variation of the Fe ion concentration in the electrolyte. - Highlights: • Structural and magnetic properties of electrodeposited NiCoFe films were studied. • The Fe and Co increased and Ni decreased with increasing Fe concentration. • All films had a face-centred cubic structure irrespective of the film content. • The M{sub s} increased and H{sub c} decreased with the change of film content. • All films showed AMR.

  2. Comparison of Ab initio Low-Energy Models for LaFePO, LaFeAsO, BaFe2As2, LiFeAs, FeSe, and FeTe: Electron Correlation and Covalency

    Science.gov (United States)

    Miyake, Takashi; Nakamura, Kazuma; Arita, Ryotaro; Imada, Masatoshi

    2010-04-01

    Effective low-energy Hamiltonians for several different families of iron-based superconductors are compared after deriving them from the downfolding scheme based on first-principles calculations. Systematic dependences of the derived model parameters on the families are elucidated, many of which are understood from the systematic variation of the covalency between Fe-3d and pnictogen-/chalcogen-p orbitals. First, LaFePO, LaFeAsO (1111), BaFe2As2 (122), LiFeAs (111), FeSe, and FeTe (11) have overall similar band structures near the Fermi level, where the total widths of 10-fold Fe-3d bands are mostly around 4.5 eV. However, the derived effective models of the 10-fold Fe-3d bands (d model) for FeSe and FeTe have substantially larger effective onsite Coulomb interactions U˜ 4.2 and 3.4 eV, respectively, after the screening by electrons on other bands and after averaging over orbitals, as compared to ˜2.5 eV for LaFeAsO. The difference is similar in the effective models containing p orbitals of As, Se or Te (d p or d p p model), where U ranges from ˜4 eV for the 1111 family to ˜7 eV for the 11 family. The exchange interaction J has a similar tendency. The family dependence of models indicates a wide variation ranging from weak correlation regime (LaFePO) to substantially strong correlation regime (FeSe). The origin of the larger effective interaction in the 11 family is ascribed to smaller spread of the Wannier orbitals generating larger bare interaction, and to fewer screening channels by the other bands. This variation is primarily derived from the distance h between the pnictogen/chalcogen position and the Fe layer: The longer h for the 11 family generates more ionic character of the bonding between iron and anion atoms, while the shorter h for the 1111 family leads to more covalent-bonding character, the larger spread of the Wannier orbitals, and more efficient screening by the anion p orbitals. The screened interaction of the d model is strongly orbital

  3. A imagem de Lagos enquanto destino turístico: perspectiva dos turistas versus perspectiva dos residentes

    OpenAIRE

    Agapito, Dora

    2010-01-01

    Dissertação de mest., Marketing, Faculdade de Economia, Univ. do Algarve, 2010 O estudo da imagem dos destinos turísticos tem vindo a afirmar-se como instrumento de diferenciação, contribuindo para o aumento da competitividade dos destinos. Apesar de ser um tema bem documentado na literatura, assiste-se a uma carência de estudos que permitam comparar as perspectivas dos turistas, público pelo qual as organizações responsáveis pela gestão dos destinos competem pela atenção, com ...

  4. Análisis de los riesgos musculoesqueléticos asociados a los trabajos de ferrallas: Buenas prácticas Musculoskeletal risks analysis related to steel reinforcement works: Good practices

    Directory of Open Access Journals (Sweden)

    Mónica López Alonso

    2011-12-01

    Full Text Available Los problemas musculo-esquelético suponen un 45% de las lesiones profesionales. Concretamente, los trabajadores que trabajan en las distintas actividades relacionadas con la producción y puesta en obra de la ferralla están expuestos a una gran cantidad de riesgos musculoesqueleticos. En este trabajo, se revisan detalladamente los riesgos ergonómicos de tipo físico de los ferrallistas. Este estudio permite comprobar que la normativa española en vigor desde 1997 (trasposición de la Directiva Europea sobre Seguridad y Salud en obras de construcción, no está corrigiendo los múltiples factores de riesgo musculoesqueléticos de estos trabajadores. Se propone para el análisis de dichos riesgos musculo-esqueléticos, la utilización de diversas metodologías ergonómicas. Una es el método Instituto Nacional de Seguridad e Higiene en el Trabajo para el estudio de la manipulación de cargas y, por otro lado, el método ERGO/ IBV desarrollado por el Instituto de Biomecánica de Valencia para el análisis de las posturas de movimientos repetitivos. El uso de dichas herramientas, permitirán el diseño de nuevos métodos de trabajo que disminuyan los riesgos analizados. Posteriormente, tras la identificación del elevado número de riesgos muculoesqueléticos, se definen una serie de BUENAS PRÁCTICAS para estos trabajadores expuestos a unas condiciones de trabajos muy exigentes y con escasa cultura preventiva.The MSD -musculoskeletal disorders- represent 45% of labour injuries. Specifically, construction workers involved in the different activities linked to steel reinforcement for an insitu concrete are exposed to a high rate of such injuries. This paper reviews in detail the physical risks of the iron worker, installing steel reinforcement for an insitu concrete pour. This study has revealed that the Spanish legislation, enforced since 1997 (transposing the European Directive on the implementation of minimum safety and health requirements at

  5. Intervenciones preventivas de la violencia interna en el trabajo: políticas de buenas prácticas y gestión de conflictos Internal violence at work preventive interventions: good practice policies and conflict management

    Directory of Open Access Journals (Sweden)

    Antonia Bernat Jiménez

    2011-01-01

    Full Text Available La violencia interna en el lugar de trabajo es la que tiene lugar entre los trabajadores, incluidos mandos y directivos. Incluye la violencia física, el acoso sexual y el acoso psicológico, abarcando también otras conductas de violencia psicológica diferenciadas de éste. Debe ser considerada como un riesgo psicosocial, que supone un peligro importante para la salud y seguridad de las personas, y tiene repercusiones organizacionales a través de costes directos e indirectos. Considerar la violencia interna con este enfoque de riesgo laboral, supone que su abordaje se ha de realizar aplicando los principios de la acción preventiva, a la vez que permite adoptar estrategias de actuación dirigidas a la prevención del fenómeno. Las principales organizaciones a nivel mundial y nacional proponen la implementación de una política de prevención de la violencia en el lugar de trabajo. Este artículo trata sobre la conveniencia del desarrollo e implementación en las organizaciones de una política de prevención de la violencia interna, de carácter integral e integrado, que involucre a toda la organización, orientada a lograr entornos de trabajo más saludables y con un enfoque centrado en los factores organizativos y psicosociales. En el artículo se contemplan las premisas esenciales de esa política preventiva de la violencia interna, abordándose también los momentos básicos de la estrategia preventiva: - La evaluación de riesgo psicosociales. - La política de buenas prácticas. - Los procedimientos de gestión de conflictos y acoso psicológico en el trabajo. - Las estrategias de comunicación organizacional y las acciones formativas. Para conseguir auténtica efectividad, las políticas de prevención de la violencia interna deben incorporarse al Sistema de Gestión de la Prevención de la organización, que, a su vez, estará integrado en todos los sistemas de gestión restantes de la empresa.Internal violence in the workplace is

  6. Prácticas culturales y gestión del riesgo sísmico: la cultura de las buenas costumbres / Cultural practices and seismic risk management: culture of good habits

    Directory of Open Access Journals (Sweden)

    Lina A. Zambrano-Hernández

    2015-10-01

    Full Text Available Resumen Objetivo: reconocer y comprender las prácticas culturales y sentidos referidos a la gestión del riesgo sísmico de un grupo poblacional que ha vivido diversas situaciones de este tipo, en la ciudad de Manizales, Caldas. Metodología: este estudio se ubicó en el campo de la investigación cualitativa, basado en la micro-etnografía y el análisis cualitativo, asumiendo como fundamento que la investigación de este tipo centra sus análisis en el contexto histórico cultural de las comunidades. Resultados: las prácticas culturales relacionadas con la gestión del riesgo son creaciones de significado que a partir del saber popular se configuran con su particular modelo de internalización cultural frente al fenómeno sísmico. Este proceso de aprendizaje comunitario se soporta a partir de convenciones morales y valores familiares que apremian desde una ideología de prevención y supervivencia, lo que se constituye para dicha comunidad en un hecho legítimo. Por otra parte, se encuentra, la no apropiación simbólica del conocimiento de carácter técnico-científico, situación que genera resistencias comunitarias a la apropiación de los nuevos contenidos, por no sentir un verdadero respeto e inclusión de su tradición cultural. Conclusión: la gestión del riesgo no es sólo la reducción de éste, sino la comprensión social de las prácticas culturales, de conductas y modos de vida (incluso de ideologías y de perspectivas de mundo, de vida, de religión, que en términos sociales, requiere de la participación de los diversos estratos, sectores de interés y grupos representativos, y así, reconocer cómo se construye en colectivo la gestión del riesgo como una cultura de las buenas costumbres./ Abstract Objective: to recognize and understand cultural practices and meanings related to seismic risk management of a community that has lived different situations of this kind in the city of Manizales, Caldas. Methodology: is a

  7. Apendicitis neonatal: Reporte de dos casos

    Directory of Open Access Journals (Sweden)

    María José Maldonado

    2017-04-01

    Full Text Available La apendicitis neonatal es una patología infrecuente, de difícil diagnóstico y con una mortalidad elevada. Se han estudiado diversas teorías sobre su etiología que consideran que la apendicitis en el periodo neonatal podría corresponder a una manifestación de inmadurez inmunitaria. El cuadro clínico de apendicitis en este grupo etáreo no tiene las características clásicas, incluyendo signos y síntomas inespecíficos, que pueden corresponder a patologías más frecuentes como la enterocolitis necrotizante. La perforación intestinal constituye la complicación más frecuente y el diagnóstico se realiza usualmente de forma intraoperatoria. En el presente artículo, se describen dos neonatos con diagnóstico intraoperatorio de apendicitis, nacidos en la Clínica Universidad de La Sabana en el año 2016. En ellos, se destaca el cuadro clínico de presentación y manejo quirúrgico, los cuales permitieron identificar esta patología.

  8. Os conflitos conjugais na perspectiva dos filhos

    Directory of Open Access Journals (Sweden)

    Viviane Ribeiro Goulart

    2013-01-01

    Full Text Available Se investigó sobre la perspectiva de los hijos en los conflictos conyugales. Participaron 17 estudiantes de una escuela pública de Porto Alegre (RS, de ambos sexos, reunidos en dos grupos focales: uno con 8 niños (8-9 años, y otro con 9 jóvenes (12-13 años, que vivían con sus padres. Cada grupo ha tenido sólo una cita en la escuela. Las informaciones fueron grabadas, transcritas y el contenido analizado a partir de los temas emergentes. De acuerdo con los niños, los conflictos conyugales van desde una discusión hasta la agresión física, son recurrientes, versan sobre cualquier tema, y su expresión es predominantemente negativa. Los niños reconocen la existencia del conflicto pero ni siempre entienden sus causas y todavía sufren sus consecuencias. Los niños adoptan distintas estrategias para lidiar con los conflictos, desde ignorarlos hasta las actitudes autodestructivas. Se concluye que los sujetos son conscientes de los conflictos conyugales de sus padres y reconocen sus repercusiones.

  9. Angiografia por tomografia computadorizada dos aneurismas intracranianos

    Directory of Open Access Journals (Sweden)

    Laureano Vinícius Santos

    2002-01-01

    Full Text Available Este trabalho foi realizado para avaliar os achados da angiografia por tomografia computadorizada, comparativamente à angiografia por subtração digital, em relação aos aneurismas intracranianos, e a possibilidade da maior utilização da angiografia por tomografia computadorizada no Brasil. Foram analisados oito pacientes que apresentavam um total de sete aneurismas não tratados e um aneurisma tratado. Houve subseqüente correlação com outros trabalhos publicados na literatura médica. Os exames foram realizados em uma clínica e em dois hospitais privados, na cidade do Rio de Janeiro, RJ. Foi demonstrada boa correlação entre os métodos estudados, em relação ao diagnóstico dos aneurismas, no acompanhamento e avaliação pré-terapêutica dessas lesões. A angiografia por tomografia computadorizada foi um exame menos invasivo, de menor custo e maior acessibilidade. Concluiu-se que a angiografia por tomografia computadorizada é um exame que deve ser utilizado com maior freqüência para avaliação nesta enfermidade.

  10. As Lutas dos Desempregados na Argentina

    Directory of Open Access Journals (Sweden)

    Kátia Iris Marro

    2012-04-01

    Full Text Available

    Este artigo aborda pesquisa sobre alguns elementos do significado político-social das lutas dos trabalhadores desempregados na Argentina que, como expressão de um “novo” quadro histórico aberto a partir da ofensiva
    do capital pela desestruturação do trabalho –contrarreformas econômicas e político-sociais que se consolidam a partir da década de 1990 –, evidenciam
    um momento de redefinição da identidade de luta das classes subalternas.
    Nessa direção, o artigo conclui que ao tempo em que esses sujeitos mostraram
    traços de resistência na configuração da “questão social”, ensaiaram episódicas
    – porém importantes – tentativas de reconstrução da iniciativa autônoma na
    experiência histórica das classes subalternas.

  11. THE PESSIMISM IN POETRY AUGUSTO DOS ANJOS

    Directory of Open Access Journals (Sweden)

    Wellington Lima Amorim

    2017-04-01

    Full Text Available Augusto dos Anjos is part of a select group of writers who, having dived deep into human existence, created in Brazilian literature works fleeing the commonplaces of his time and carnivalization condition attributed to the cultural diversity of Brazilian land, a view that is both distorted and obscured the true power of our artists. Pessimism takes thus an essential function: to question what you're doing and how you are doing, since all major pessimists are, deep down, great realistic. The purpose of this study is to evaluate the pessimism of Augustan poetry of the Angels and identify innovative reflections that his verses present. For this, read to your unique work, "I", and poems published in youth and some of his critics and leading scholars, as Raimundo Magalhaes Junior and poet Gullar. The methodology used was the literature review, assessing the poetry of the author and his work in identifying, compared to the thought of his time, the genesis of their uniqueness in our literature. Keywords: Poetry. Pessimism. Reflection.

  12. Dos celebraciones religiosas en un mundo globalizado

    Directory of Open Access Journals (Sweden)

    María Iracheta

    2009-01-01

    Full Text Available Este artículo intenta responder a la pregunta ¿cómo permanecen dos fiestas religiosas mexicanas -la de la Nuestra Señora de Tonatico, en su Santuario, ubicado en el municipio de Tonatico, Estado de México y la de la Virgen del Rosario en su iglesia del Barrio de Xochimilco, -en la ciudad de Oaxaca, capital del Estado de Oaxaca, -en el contexto de la modernización y la globalización? Tres elementos ayudan a explicar esta permanencia: la tradición, que es asumida y reproducida por el "linaje de creyentes" pasados, presentes y futuros; el ritual, que reproduce la memoria histórica y la identidad local; y la apropiación de elementos culturales ajenos a la cultura local para sobrevivir en contextos globales. Estas celebraciones permiten restituir la armonía en los pueblos o barrios, que han cambiado drásticamente por la inserción de los mismos en un mercado mundial. También generan la percepción de tener el control de la comunidad frente a los grandes procesos externos que la amenazan: la mancha urbana, el comercio internacional, los medios masivos de comunicación, la cultura de masas, entre otros.

  13. Characterisations of CoFeCu films: Influence of Fe concentration

    Energy Technology Data Exchange (ETDEWEB)

    Kockar, Hakan, E-mail: hkockar@balikesir.edu.tr [Physics Department, Science and Literature Faculty, Balikesir University, 10145 Cagis, Balikesir (Turkey); Ozergin, Ercument, E-mail: ercmentz@yahoo.com [Physics Department, Science and Literature Faculty, Balikesir University, 10145 Cagis, Balikesir (Turkey); Karaagac, Oznur, E-mail: karaagac@balikesir.edu.tr [Physics Department, Science and Literature Faculty, Balikesir University, 10145 Cagis, Balikesir (Turkey); Alper, Mursel, E-mail: malper@uludag.edu.tr [Physics Department, Science and Literature Faculty, Uludag University, 16059 Gorukle, Bursa (Turkey)

    2014-02-15

    Highlights: • Electrodeposited ternary CoFeCu alloy may be a promising alternative of currently used materials. • CoFeCu films were deposited from the electrolytes with different Fe concentrations. • Structure changed from the mixed phase of hcp and fcc to the fcc and finally bcc with increasing Fe. • Needle-like shapes turned to roundish structures with increasing Fe concentration. • Saturation magnetisation increased and coercivity decreased with increasing Fe concentration. -- Abstract: The properties of electrodeposited CoFeCu films were studied with respect to Fe ion concentration in the electrolyte due to their interesting magnetic properties like high saturation magnetisation and low coercivity. The films were characterised in terms of microstructural and magnetic properties. From the compositional analysis, the Fe contents in the films are found to be consistent with the Fe ion concentrations in the electrolytes. With the surface morphology analysis of the films, the number of the roundish shape structures on the surface increased with increasing Fe ion concentration (⩾0.01 M Fe) whereas the CoCu films (0 M Fe) had ridged grains. The crystal structure of the films, examined by X-ray diffraction, changed from the mixed phase of the hexagonal close packed and face centered cubic (fcc) to the fcc and finally body centered cubic structure as the Fe ion concentration in the electrolyte increased from 0 to 0.04 M. And, the average grain size decreased with increasing Fe ion concentration. Magnetisation measurements by vibrating sample magnetometer displayed that the saturation magnetisation increased and the coercivity decreased as the Fe ion concentration increased. Also, it was found that the easy-axis of the magnetisation of films is parallel to the film plane. All films showed anisotropic magnetoresistance. The longitudinal and transverse magnetoresistance magnitudes of the films changed between 3.2–4.0 and 3.0–3.8, respectively. In the study

  14. Thickness of the Post-Perovskite Boundary in Fe2+ and Fe3+ Bearing Systems

    Science.gov (United States)

    Shim, S.; Catalli, K.; Prakapenka, V.

    2008-12-01

    Combined with seismic observations of the D" region, the perovskite (Pv) to postperovskite (PPv) transition provides new opportunities to constrain important parameters at the core-mantle boundary, such as heat flux from the core through the observation of the double crossing between the geotherm and the PPv transition. In the mantle, the PPv boundary should have a finite thickness. We have determined the PPv boundary thickness in 0.9MgSiO3-0.1FeSiO3 and 0.9MgSiO3-0.1Fe2O3 in the laser-heated diamond cell combined with in situ X-ray diffraction. In order to reduce thermal and pressure gradients, we use argon as a medium. In order to reduce the kinetic effect, we measured the boundary along both forward (from Pv to PPv) and reverse (from PPv to Pv) paths. Our data tightly constrain the transition depth and Clapeyron slope (+6.7±0.5 MPa/K in Fe2+ and +8.4±1.0 MPa/K in Fe3+) and the results are consistent with seismological observations. However, 10 mol% Fe2+ increases the thickness to 450±50 km which is significantly larger than the thickness of the D" discontinuity (≤80 km), whereas 10 mol% Fe3+ increases the thickness to only about 100±50 km. The discrepancy with the seismic observation for Fe2+ can be reconciled by assuming strong partitioning of Fe to ferropericlase (Fp) such that PPv is much more depleted in Fe than Pv. However, the partitioning of Fe among Pv, PPv, and Fp is highly controversial. An Fe3+-enriched lower mantle provides a natural explanation for the thickness of the D" discontinuity. These two models can be further examined for the high electrical conductivity required by the observation of the Earth's nutation. The low Fe2+ in Pv and PPv and high Fe2+ in Fp would result in very low electrical conductivity. However, an Fe3+-enriched lower mantle would have high electrical conductivity because Fe3+--O bonding becomes metallic in the PPv structure and the coexistence of Fe2+ and Fe3+ will enhance electron hopping between these two. Therefore

  15. ESPERA, ESPERANZA, FE Y TURISMO

    Directory of Open Access Journals (Sweden)

    Anna María Fernández Poncela

    2013-06-01

    Full Text Available El texto revisa los conceptos y sentimientos relacionados con la espera y la esperanza. El estudio se centra en espacios de turismo religioso. Espacios donde el tiempo parece detenido y los devotos depositan su fe y los turistas visitan también. En concreto en Zapopan, municipio junto a la ciudad de Guadalajara, Jalisco, México. En una época donde el turismo busca lo auténtico, la experiencia y las emociones, el turismo religioso aumenta y algunos lugares son más populares que nunca.This text reviews the some concepts and feelings related to the wait and hope. The study focuses on spaces of religious tourism. Spaces where the time seems stopped and devotees deposited their faith and tourists also visit this spaces too. In particular in Zapopan, a municipality near the city of Guadalajara, Jalisco, Mexico. Today tourism looking for authentic, experience and emotions, religious tourism increases and some places are more popular than ever.

  16. First-principles study on the thermodynamic stability, magnetism, and half-metallicity of full-Heusler alloy Ti{sub 2}FeGe (001) surface

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Yan; Zhang, Jian-Min, E-mail: jmzhang@snnu.edu.cn

    2017-05-10

    For the Ti{sub 2}FeGe Heusler alloy, the surface stability, electronic and magnetic properties of the various (001) surfaces have been studied by using first-principles calculations. The TiGe termination is the most stable one while the GeGe* termination is the most unstable one. Both the density of states (DOS) and atomic magnetic moments (AMMs) of the central layers are similar to the corresponding bulk characters due to no influence of surface effect as we expected. The TiGe termination has the highest spin polarization 96.67%, followed by the TiFe (67.17%), GeGe* (66.51%) and FeFe* terminations (62.02%). The TiTi* terminations has the lowest spin polarization 61.31%. The magnetic moments for atoms on the surfaces and subsurfaces of these terminations are different from the bulk case. - Highlights: • TiGe termination is the most stable while GeGe* termination is the most unstable. • TiGe termination has the highest spin polarization followed by TiFe, GeGe*, FeFe* and TiTi*. • Atomic magnetic moments at the (001) surfaces are greatly different from the bulk values.

  17. Mössbauer spectroscopic studies in U-Fe and U-Fe-Zr alloys

    Energy Technology Data Exchange (ETDEWEB)

    Panda, Alaka; Singh, L. Herojit; Rajagopalan, S.; Govindaraj, R., E-mail: govind@igcar.gov.in; Ramachandran, Renjith; Kalavathi, S.; Amarendra, G. [Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam (India)

    2016-05-23

    {sup 57}Fe Mössbauer studies have been carried out in an alloy of U and Fe with atomic percentage in the ratio of 68%:32% in order to understand the local structure and valence of Fe atoms associated with different phases that may get formed. The effect of changes in the hyperfine parameters such as isomer shift and quadrupole splitting at Fe sites due to additional alloying of Zr has been studied in an alloy of U, Fe and Zr in the ratio of 44%:33%:23% respectively with respect to that of the U-Fe alloy chosen in the present study. Possible effect of solute clustering in these systems has been addressed in an analogous alloy of uranium and zirconium using positron lifetime spectroscopy.

  18. Anisotropic magnetic property of nanocomposite Nd2Fe14B/Mo/α-Fe multilayer films

    Science.gov (United States)

    Kobayashi, K.; Ogawa, D.; Koike, K.; Kato, H.; Oogane, M.; Miyazaki, T.; Ando, Y.; Itakura, M.

    2017-10-01

    We fabricated the MgO(100)/Mo/[Nd2Fe14B/Mo/Fe/Mo]5/Mo multilayer films, in which we tried to avoid the negative J ex interfaces and thermal diffusion between Nd2Fe14B and α–Fe layers by forming the stacked structure with ultra thin Mo interlayer. The films without Mo interlayer showed isotropic magnetic properties, while films with Mo interlayer thickness t Mo = 1 nm exhibited the perpendicular anisotropy with the coercivity of 7 kOe. Shapes for the major loop and the first order reversal curves (FORCs) suggested an existence of positive exchange coupling between the Nd-Fe-B and the α–Fe layers via the 1 nm thick Mo interlayer.

  19. Summary of Fe opacity measurement platform

    Energy Technology Data Exchange (ETDEWEB)

    Nagayama, Taisuke

    2016-05-01

    This powerpoint presentation goes over the Fe opacity measurement platform, including how the experiment works, what can be gathered from the measurements, what can be gathered from the simulations, and the limitations of the experiment.

  20. Dialogo, razon y fe, ciencia y evangelio

    National Research Council Canada - National Science Library

    Parra, Alberto

    2009-01-01

    ... de un dialogo capaz de clarificar una vez mas las vias de una articulacion efectiva entre razon y fe, ciencia y evangelio, en aras de lograr los propositos expresados en el principio que intenta inspirar dicho dialogo...

  1. Análise da lucratividade dos clientes

    OpenAIRE

    Madeira, Paulo

    2000-01-01

    Um bom sistema de Análise da lucratividade de Clientes pode ajudar a melhorar a rendibilidade global do negócio, selecionando os clientes de qualidade, e a indicar o principal caminho a segui rpara atingir uma maior lucartividade, indicando o impacto financeiro actual e potencial dos movimentos estratégicos dos clientes.

  2. Magnetic properties of ball-milled TbFe2 and TbFe2B

    Indian Academy of Sciences (India)

    Unknown

    Dhilsha and Rama Rao (1990) reported single particle excitations in Co substituted Ho0⋅85Tb0⋅15Fe2, through ele- ctrical resistivity measurements. Low temperature mag- netization studies on Ni substituted Dy0⋅73Tb0.27Fe2 and. Ho0⋅85Tb0⋅15Fe2 have revealed domain wall pinning (Senthil. Kumar et al 1995).

  3. Role of aluminium addition on structure of Fe substituted Fe73·5 ...

    Indian Academy of Sciences (India)

    Both XRD and TEM results confirm that the precipitated nanocrystalline phase is either DO3 phase or bcc α-Fe(Si/Al) solid solution depending on the initial composition of the alloy. The bcc α-Fe(Si/Al) solid solution was found to be stabilized with increasing Al up to 2 at% as compared to the ordered DO3 structure of Fe3Si ...

  4. Studies on the valence electronic structure of Fe and Ni in Fe Ni ...

    Indian Academy of Sciences (India)

    -to- X-ray intensity ratios of Fe and Ni in pure metals and in FeNi1- alloys ( = 0.20, 0.50, 0.58) exhibiting similar crystalline structure have been measured following excitation by 59.54 keV -rays from a 241Am point source, to understand as to why the properties of permalloy Fe0.2Ni0.8 is distinct from other alloy ...

  5. Modeling thermodynamics of Fe-N phases; characterisation of e-Fe2N1-z

    DEFF Research Database (Denmark)

    Pekelharing, M.I.; Böttger, A.; Somers, Marcel A.J.

    1999-01-01

    In order to arrive at modeling the thermodynamics of Fe-N phases, including long-range (LRO) and short-range ordering (SRO) of the N atoms, it is important to understand the role of N interstitially dissolved in an Fe-host lattice. The crystal structure of -Fe2N1-z consists of an h.c.p. iron sub...... for extinguished superstructure reflections in the X-ray diffractogram of configuration A....

  6. High Temperature Magnetic Properties of Indirect Exchange Spring FePt/M(Cu,C/Fe Trilayer Thin Films

    Directory of Open Access Journals (Sweden)

    Anabil Gayen

    2013-01-01

    Full Text Available We report the investigation of temperature dependent magnetic properties of FePt and FePt(30/M(Cu,C/Fe(5 trilayer thin films prepared by using magnetron sputtering technique at ambient temperature and postannealed at different temperatures. L10 ordering, hard magnetic properties, and thermal stability of FePt films are improved with increasing postannealing temperature. In FePt/M/Fe trilayer, the formation of interlayer exchange coupling between magnetic layers depends on interlayer materials and interface morphology. In FePt/C/Fe trilayer, when the C interlayer thickness was about 0.5 nm, a strong interlayer exchange coupling between hard and soft layers was achieved, and saturation magnetization was enhanced considerably after using interlayer exchange coupling with Fe. In addition, incoherent magnetization reversal process observed in FePt/Fe films changes into coherent switching process in FePt/C/Fe films giving rise to a single hysteresis loop. High temperature magnetic studies up to 573 K reveal that the effective reduction in the coercivity decreases largely from 34 Oe/K for FePt/Fe film to 13 Oe/K for FePt/C(0.5/Fe film demonstrating that the interlayer exchange coupling seems to be a promising approach to improve the stability of hard magnetic properties at high temperatures, which is suitable for high-performance magnets and thermally assisted magnetic recording media.

  7. Low-temperature hydrothermal synthesis of α-Fe/Fe3O4 nanocomposite for fast Congo red removal.

    Science.gov (United States)

    Wang, Lixia; Li, Jianchen; Wang, Zhitao; Zhao, Lijun; Jiang, Qing

    2013-02-21

    A facile low-temperature hydrothermal process to synthesize α-Fe/Fe(3)O(4) nanocomposite is reported. TEM and HRTEM revealed that the α-Fe/Fe(3)O(4) nanocomposite was composed of catenulate α-Fe and lamellar structured Fe(3)O(4). The weight ratio of α-Fe in the α-Fe/Fe(3)O(4) nanocomposite is 35.6%. The α-Fe/Fe(3)O(4) nanocomposite demonstrates an extremely high Congo red (CR) removal efficiency from waste water showing almost complete removal within 3 min. For 100 mg L(-1) of CR aqueous solution, the maximum CR removal can reach 1297.06 mg g(-1). The large saturation magnetization (80.5 emu g(-1)) of the nanocomposite allows fast separation of α-Fe/Fe(3)O(4) nanoparticles loaded with CR from the liquid suspension. The synergistic effect of the nanocomposite may contribute to the enhanced CR removal ability, because the CR can be removed by reduction reaction and adsorption at the same time. Based on the degradation products identified by UV-Vis spectra, XRD and FTIR spectra, a possible degradation mechanism of CR on the α-Fe/Fe(3)O(4) composite was proposed. The significantly reduced treatment time required to remove the CR and the simple, low-cost and pollution-free preparation method make α-Fe/Fe(3)O(4) nanocomposite promising for highly efficient removal of dyes from waste water.

  8. Aleaciones cuasicristalinas Al93Fe3Cr2Ti2

    Directory of Open Access Journals (Sweden)

    García-Escorial, Asunción

    2015-12-01

    Full Text Available Aluminium alloy powder having a nominal composition of Al93Fe3Cr2Ti2 (at% has been prepared using gas atomisation. The atomised powder present a microstructure of an aluminium matrix reinforced with a spherical quasicrystalline icosahedral phase, in the range of nanometre in size. The powder was consolidated into bars using warm extrusion. The microstructure of the extruded bars retains the quasicrystalline microstructure and the bars present outstanding mechanical properties, i.e. proof stress of 280 MPa at 300 °C. Upon heating the microstructure evolves towards the equilibrium. The thermal evolution was investigated by means of x-ray diffraction, differential scanning calorimeter, scanning electron microscopy and transmission electron microscopy. According to these observations a transformation in two steps is proposed. A first step consists in the decomposition of the supersaturated solid solution of the matrix and the quasicrystals, and a second step in the transformation of the quasicrystals into the equilibrium phases.Se ha obtenido por atomización por gas polvo de la aleación Al93Fe3Cr2Ti2 (at%. Este polvo presenta una microestructura de una matriz de aluminio reforzada por precipitados icosaédricos de tamaño nanométrico. El polvo fue consolidado por extrusión en forma de barras cilíndricas. La microestructura de las barras retiene la microestructura cuasicristalina de las partículas de polvo. El material consolidado presenta propiedades mecánicas prometedoras, como un límite elástico de 280 MPA a 300 °C. Con los tratamientos térmicos, la microestructura evoluciona hacia el equilibrio. Esta evolución se estudia por difracción de rayos x, calorimetría diferencial de barrido, microscopías electrónicas de barrido y de transmisión. A la luz de los resultados obtenidos se propone que la transformación de las fases con el tiempo de tratamiento térmico ocurre en dos pasos. Primeramente, tiene lugar la descomposición de la

  9. Prevención de la violencia de género en las universidades: Características de las buenas prácticas dialógicas

    OpenAIRE

    Mendoza Morteo, Marlen

    2011-01-01

    [spa] La tesis analiza el problema de la violencia de género al interior de las universidades. El estudio se compone de dos grandes dimensiones: 1) el análisis de la presencia del fenómeno en diferentes grupos poblacionales: académicas, estudiantes y trabajadoras o miembros del personal de servicios; y 2) el estudio de las prácticas y estrategias que pueden contribuir a su prevención y superación del ambiente universitario. La primera parte corresponde a la dimensión metodológica y los a...

  10. Ruídos e barulhos na unidade neonatal

    OpenAIRE

    Maria Vera Lúcia Moreira Leitão Cardoso; Edna Maria Camelo Chaves; Maria Gorette Andrade Bezerra

    2010-01-01

    Objetivou-se identificar os fatores causadores de ruídos e mensurar os ruídos em decibéis na unidade neonatal. Estudo descritivo, desenvolvido numa instituição pública, Fortaleza-Ce. A coleta dos dados ocorreu nos turnos da manhã, tarde, noite de outubro/2004 a janeiro/2005. Os dados foram coletados mediante observação não participante, tendo registrado a medição dos ruídos em nível de pressão sonora, usando-se um decibelímetro. Os resultados apontaram o turno da manhã com níveis altos de ruí...

  11. Magnetic properties of Fe-oxide and (Fe, Co) oxide nanoparticles synthesized in polystyrene resin matrix

    Science.gov (United States)

    Rodak, D.; Kroll, E.; Tsoi, G. M.; Vaishnava, P. P.; Naik, R.; Wenger, L. E.; Suryanarayanan, R.; Naik, V. M.; Boolchand, P.

    2003-03-01

    Magnetic nanoparticles have potential applications ranging from drug delivery and imaging in the medical field to sensing and memory storage in technology. The preparation, structure, and physical properties of iron oxide-based nanoparticles synthesized by ion exchange in a polystyrene resin matrix have been investigated. Employing a synthesis method developed originally by Ziolo, et. al^1, nanoparticles were prepared in a sulfonated divinyl benzene polystyrene resin matrix using various aqueous solutions of (1) FeCl_2, (2) FeCl_3, (3) FeCl2 : 2FeCl3 , (4) 9FeCl2 : CoCl_2, and (5) 4FeCl2 : CoCl_2. Powder x-ray diffraction measurements were used to identify the phases present while transmission electron microscopy was used for particle size distribution determinations. SQUID magnetization measurements (field-cooled and zero-field-cooled) and Fe^57 Mössbauer effect measurements indicate the presence of ferromagnetic iron oxide phases and a superparamagnetic behavior with blocking temperatures (T_B) varying from 50 K to room temperature. Nanoparticles synthesized using a stoichiometric mixture of FeCl2 and FeCl3 exhibit the lowest TB and smallest particle size distribution. The Mössbauer effect measurements have also been used to identify the iron oxides phases present and their relative amounts in the nanoparticles ^1R.F. Ziolo, et al., Science 207, 219 (1992). *Permanent address: Kettering University, Flint, MI 48504

  12. High-pressure electrical resistivity studies on FeSe2 and FeTe2

    Science.gov (United States)

    Parthasarathy, G.; Sharma, D. K.; Sharma, Y. K.; Chandra, Usha

    2013-02-01

    We report here for the first time the pressure dependence of the electrical resistivity of ferroselite (FeSe2) and frohbergite FeTe2 up to 8 GPa. The synthetic ferroselite shows a pressure induced marcasite-to-NiAs type structural phase transition at 6.8 GPa and frohbergite shows the transition at 5.7 GPa. The transition was observed with a discontinuous resistivity decrease by 0.9 times. We also present here the XRD results on the FeSe2 and FeTe2. The relevance of the phase transition to Martian mineral chemistry is discussed.

  13. Collective spin waves in Fe-Pd and Fe-W multilayer structures

    Energy Technology Data Exchange (ETDEWEB)

    Hillebrands, B.; Baumgart, P.; Mock, R.; Guentherodt, G.; Boufelfel, A.; Falco, C.M.

    1986-12-15

    The complete, theoretically predicted band of collective magneto- static spin-wave excitations has been observed for the first time in Fe-Pd and Fe-W multilayer structures by Brillouin scattering. Despite the large number of bilayers (49--90) discrete spin-wave modes due to a quantization of the momentum perpendicular to the stack have been observed in the upper half of the band. For Fe-Pd multilayer structures the saturation magnetization shows a monotonic decrease of up to 30% from that of the bulk Fe for modulation wavelengths down to 33 A.

  14. Vacancy ordering in γ-Fe 2O 3 nanocrystals observed by 57Fe NMR

    Science.gov (United States)

    Bastow, T. J.; Trinchi, A.; Hill, M. R.; Harris, R.; Muster, T. H.

    2009-09-01

    The identification by 57Fe internal field nuclear magnetic resonance (NMR) of hyperfine fields at four Fe sites in the (average) tetragonal unit cell of vacancy-ordered γ-Fe 2O 3 (maghemite) is reported. The effects of vacancy redistribution due to annealing the partially vacancy-ordered form has been observed in the 57Fe lineshape. In addition, the reduction of the particle size of the vacancy-ordered form has been observed to gradually eliminate the vacancy ordering and then to cause a transition from ferrimagnetism to superparamagnetism.

  15. Studies of an Fe9 tridiminished icosahedron.

    Science.gov (United States)

    Tolis, Evangelos I; Engelhardt, Larry P; Mason, Pamela V; Rajaraman, Gopalan; Kindo, Koichi; Luban, Marshall; Matsuo, Akira; Nojiri, Hiroyuki; Raftery, James; Schröder, Christian; Timco, Grigore A; Tuna, Floriana; Wernsdorfer, Wolfgang; Winpenny, Richard E P

    2006-12-04

    The synthesis and structural characterization of a nonanuclear FeIII cage complex is reported. The nine iron centers in [Fe9(mu3-O)4(O3PPh)3(O2CCMe3)13] lie on the vertices of an incomplete icosahedron, with the P atoms of triphenylphosphonate at the other three vertices. The paramagnetic core therefore describes a tridiminished icosahedron. Magnetic studies suggest an S=1/2 ground state for the molecule. Analysis of exchange paths and the susceptibility data point to the interpretation that the cluster can be divided into two nearly decoupled sections: an {Fe6O3} section, with an S=0 ground state, in which three oxo-centered triangles bound a central triangle that is not oxo-centered; and an {Fe3O} triangle with S=1/2. The analysis of the susceptibility data leads to a Heisenberg model based on three significant antiferromagnetic exchange interactions, with values of 173.7 cm-1 in the {Fe3O} triangle, and 30.9 and 19.1 cm-1 within the {Fe6O3} section, while the exchange between them is <1 cm-1. With these assignments, the theoretical low-temperature differential susceptibility is also in very good agreement with measurements up to 50 T. Magnetic measurements in the milli-kelvin range reveal striking hysteresis loops and magnetization reversals associated with a Landau-Zener-Stückelberg (LZS) transition as enhanced by the occurrence of a phonon bottleneck.

  16. Structure of nanocomposites of Al–Fe alloys prepared by ...

    Indian Academy of Sciences (India)

    Wintec

    Abstract. Structures of Al-based nanocomposites of Al–Fe alloys prepared by mechanical alloying (MA) and subsequent annealing are compared with those obtained by rapid solidification processing (RSP). MA pro- duced only supersaturated solid solution of Fe in Al up to 10 at.% Fe, while for higher Fe content up to 20 at.

  17. Mechanical properties and electronic structures of Fe-Al intermetallic

    Energy Technology Data Exchange (ETDEWEB)

    Liu, YaHui; Chong, XiaoYu; Jiang, YeHua, E-mail: jiangyehua@kmust.edu.cn; Zhou, Rong; Feng, Jing, E-mail: jingfeng@kmust.edu.cn

    2017-02-01

    Using the first-principles calculations, the elastic properties, anisotropy properties, electronic structures, Debye temperature and stability of Fe-Al (Fe{sub 3}Al, FeAl, FeAl{sub 2}, Fe{sub 2}Al{sub 5} and FeAl{sub 3}) binary compounds were calculated. The formation enthalpy and cohesive energy of these Fe-Al compounds are negative, and show they are thermodynamically stable structures. Fe{sub 2}Al{sub 5} has the lowest formation enthalpy, which shows the Fe{sub 2}Al{sub 5} is the most stable of Fe-Al binary compounds. These Fe-Al compounds display disparate anisotropy due to the calculated different shape of the 3D curved surface of the Young’s modulus and anisotropic index. Fe{sub 3}Al has the biggest bulk modulus with the value 233.2 GPa. FeAl has the biggest Yong’s modulus and shear modulus with the value 296.2 GPa and 119.8 GPa, respectively. The partial density of states, total density of states and electron density distribution maps of the binary Fe-Al binary compounds are analyzed. The bonding characteristics of these Fe-Al binary compounds are mainly combination by covalent bond and metallic bonds. Meanwhile, also exist anti-bond effect. Moreover, the Debye temperatures and sound velocity of these Fe-Al compounds are explored.

  18. Density of phonon states in superconducting FeSe as a function of temperature and pressure

    Science.gov (United States)

    Ksenofontov, V.; Wortmann, G.; Chumakov, A. I.; Gasi, T.; Medvedev, S.; McQueen, T. M.; Cava, R. J.; Felser, C.

    2010-05-01

    The temperature and pressure dependence of the partial density of phonon states (phonon-DOS) of iron atoms in superconducting Fe1.01Se was studied by F57e nuclear inelastic scattering. The high-energy resolution allows for a detailed observation of spectral properties. A sharpening of the optical phonon modes and shift of all spectral features toward higher energies by ˜4% with decreasing temperature from 296 to 10 K was found. However, no detectable change at the tetragonal-orthorhombic phase transition around 100 K was observed. Application of a pressure of 6.7 GPa, connected with an increase in the superconducting temperature from 8 to 34 K, results in an increase in the optical phonon mode energies at 296 K by ˜12% , and an even more pronounced increase for the lowest-lying transversal acoustic mode. Despite these strong pressure-induced modifications of the phonon-DOS we conclude that the pronounced increase in Tc in Fe1.01Se with pressure cannot be described in the framework of classical electron-phonon coupling. This result suggests the importance of spin fluctuations to the observed superconductivity.

  19. ESTUDO SOBRE O IMPACTO DOS PROCESSADORES HOSPEDEIROS

    Directory of Open Access Journals (Sweden)

    Alba S. B. Lopes

    2008-05-01

    Full Text Available Arquiteturas reconfiguráveis são dispositivos de hardware capazes de modificar sua estrutura de hardware de acordo com a aplicação a ser executada. Tais dispositivos surgiram como uma alternativa às soluções de hardware tradicionais na tentativa de equilibrar flexibilidade e desempenho. Uma das principais formas de utilização de arquiteturas reconfiguráveis corresponde a um bloco reconfigurável anexado a um processador hospedeiro. Esse processador é responsável por executar diversas tarefas críticas, incluindo o particionamento hardware/software e indicar o momento do bloco reconfigurável executar. Apesar de existirem diversas propostas de arquiteturas reconfiguráveis na literatura, pouco se estudou sobre o impacto do processador hospedeiro na arquitetura. Nesse contexto, esse artigo apresenta um estudo sobre o impacto do processador hospedeiro no desempenho da arquitetura reconfigurável híbrida. Como estudo de caso foi realizada uma avaliação sobre o uso dos processadores SPARC V8 da Sun Microsystems e Nios II da Altera como processadores hospedeiros da arquitetura reconfigurável híbrida RoSA. O objetivo deste estudo é realizar a comparação entre o desempenho desses processadores e identificar qual deles é o mais adequado para anexar a arquitetura em questão. Os resultados mostraram que foi possível alcançar até 47% de ganho de desempenho com o uso do processador Nios II em comparação ao SPARC V8, indicando o primeiro como mais adequado para a arquitetura RoSA. PALAVRAS-CHAVE: arquiteturas reconfiguráveis, processador hospedeiro, desempenho.

  20. ECTIMA CONTAGIOSO (DERMATITE PUSTULAR DOS OVINOS

    Directory of Open Access Journals (Sweden)

    Monica Weismann Seabra Salles

    1992-12-01

    Full Text Available É descrito um surto de ectima contagioso em ovinos no Rio Grande do Sul nos meses de junho e julho. Setenta (78% de um total de 90 cordeiros de 10 a 45 dias de idade foram afetados. Não houve mortes. Também 3 ovelhas adultas desenvolveram lesões discretas na pele ao redor da boca. Os cordeiros apresentavam proliferações crostosas firmes, nodulares ou em forma de placas na pele da boca e junção mucocutânea da cavidade oral. Lesões proliferativas não ulceradas em forma de placa eram observadas no palato duro e almofada dental. Lesões proliferativas extensas, vegetantes, ocorriam na gengiva ao longo dos molares superiores e inferiores. Um cordeiro fêmea de 45 dias de idade foi sacrificado e necropsiado. As principais lesões microscópicas consistiam de epitélio hiperplástico pseudoepiteliomatoso com hiper e paraqueratose, cobrindo a derme ou a lâmina própia que se encontrava acentuadamente infiltrada por macrófagos, neutrófilos e linfócitos. Inclusões acidofílicas intracitoplasmáticas eram vistas nas células epiteliais da pele e da mucosa oral. Pústulas foram observadas na epiderme e mucosa oral. Vasculite associada a trombose era vista nos vasos da derme e lâmina própia. Numerosas partículas víricas com morfologia compatível com parapoxvírus foram encontradas em associação com as lesões epiteliais, ao exame no microscópio eletrônico. A epidemiologia, patogenia, meios de diagnóstico e profilaxia do ectima contagioso são discutidos.

  1. A compreensão dos movimentos dos leitores em documentos www

    Directory of Open Access Journals (Sweden)

    María González de Cossío

    2004-04-01

    Full Text Available Este estudo objetiva identificar os movimentos dos leitores no espaço virtual e, para tanto, está estruturado como sendo uma viagem através do ambiente da Rede Mundial de computadores (www. A World Wide Web é formada pela representação de elementos gráficos, de navegação e organizacionais, métodos de movimentação de leitores dentro de um documento da Rede e os modelos mentais que os leitores desenvolvem enquanto navegam no ambiente da Web. O conhecimento que se tem sobre navegação em espaço físico serve como modelo teórico no estudo dos movimentos dos leitores em ambientes da Rede. As etapas de obtenção de conhecimento virtual (marco/rota/exploração são examinadas e testadas e os resultados sugerem que quando os leitores interagem com documentos da Rede, eles associam os elementos gráficos a marcos. Leitores criam uma rota de conhecimento de documentos conhecidos e, conforme testes realizados, eles parecem não desenvolver conhecimento exploratório ou mapas cognitivos. E, por fim, o autor sugere que navegar por documentos da Rede deveria ser considerado como sendo uma navegação semântica e não uma navegação virtual. Neste trabalho, o autor apenas descreve os estudos conduzidos na tentativa de se descobrir se leitores desenvolvem ou não conhecimento de rotas e exploratório em conhecidos documentos www.

  2. OS VIDEOJOGOS: AS REPRESENTAÇÕES DOS PAIS SOBRE A PRÁTICA DOS FILHOS

    Directory of Open Access Journals (Sweden)

    Sílvia Coimbra

    2015-04-01

    Full Text Available Os videojogos são um fenómeno com crescimento progressivo desde a década de 70, alojando-se na vida das crianças, dos jovens e até mesmo na dos adultos. Ao passarem muitas horas em frente a um ecrã as crianças podem estar a tornar-se pequenas pessoas inativas, porque as horas que passam a jogar videojogos poderiam ser dedicadas à actividade física, tornando assim as crianças mais ativas e menos sedentárias (Bergamasco et al., 2008. O magnetismo exercido pelos videojogos pode assustar os intervenientes da educação, pois as crianças e jovens de hoje passam horas a jogar, e nesse período de tempo não se consegue saber o que é que as crianças aprendem, ou não aprendem (Pereira, 2007. As investigações nesta área têm abordado esta temática, demonstrando que é importante ter atenção aos conteúdos e número de horas que as crianças dispensam a jogar de forma a poder haver um maior controle desse tempo (Marivoet, 2001; Moita, 2007; Pereira, 2007.Objetivo: Contribuir para o conhecimento e aprofundamento da problemática dos videojogos, relativamente à representação que os pais têm sobre a sua influência no desenvolvimento das crianças, as horas que os seus filhos passam a jogar e ainda se o tempo de jogo furta tempo à actividade física.

  3. Structural stability, half-metallicity and magnetism of the CoFeMnSi/GaAs(0 0 1) interface

    Science.gov (United States)

    Feng, Yu; Chen, Xiaorui; Zhou, Ting; Yuan, Hongkuan; Chen, Hong

    2015-08-01

    The ferromagnet/semiconductor interface plays a crucial role in the performance of advanced magnetic tunnel junctions (MTJs) built of ferromagnetic electrodes and semiconductor as a spacer. We investigate the interface character between LiMgPbSb-type Heusler alloy CoFeMnSi and semiconductor GaAs by using the first-principles density functional simulations. In our calculations, we build two kinds of interface structures, namely the top-type and the bridge-type structure by connecting the termination of nine CoFeMnSi layers to the top of the As-terminated GaAs layer and the bridge site between interface As atoms, respectively. The calculated phase diagram indicated that the CoFe-terminated interface is more stable in the bridge-type structure than in the top-type structure, and a favored MnMn- or MnSi-terminated interface will appear in the top-type structure instead of the bridge-type structure under Fe-rich conditions. Besides, our calculation reveals that interface Mn and interface Fe atoms prefer to extend outward and their atom-resolved spin magnetic moments are enhanced due to the rehybridization caused by the symmetry breaking at the interface, while interface Co atoms shrink inward and their moments are decreased compared with the bulk value. Further analysis on DOS and PDOS indicates that owing to the interface effect, the half metallicity of CoFe-, MnSi-, and SiSi-terminated interfaces is completely destroyed. However, the MnMn-terminated interface in the top-type structure preserves 100% spin polarization, indicating that the CoFeMnSi/GaAs heterostructure with the top-type MnMn-terminated interface has more advantages than other atomic terminations in spintronics applications.

  4. First Experimental Constraint on the Fe59(n ,γ)Fe60 Reaction Cross Section at Astrophysical Energies via the Coulomb Dissociation of Fe60

    Science.gov (United States)

    Uberseder, E.; Adachi, T.; Aumann, T.; Beceiro-Novo, S.; Boretzky, K.; Caesar, C.; Dillmann, I.; Ershova, O.; Estrade, A.; Farinon, F.; Hagdahl, J.; Heftrich, T.; Heil, M.; Heine, M.; Holl, M.; Ignatov, A.; Johansson, H. T.; Kalantar, N.; Langer, C.; Le Bleis, T.; Litvinov, Yu. A.; Marganiec, J.; Movsesyan, A.; Najafi, M. A.; Nilsson, T.; Nociforo, C.; Panin, V.; Pietri, S.; Plag, R.; Prochazka, A.; Rastrepina, G.; Reifarth, R.; Ricciardi, V.; Rigollet, C.; Rossi, D. M.; Savran, D.; Simon, H.; Sonnabend, K.; Streicher, B.; Terashima, S.; Thies, R.; Togano, Y.; Volkov, V.; Wamers, F.; Weick, H.; Weigand, M.; Wiescher, M.; Wimmer, C.; Winckler, N.; Woods, P. J.

    2014-05-01

    The radionuclide Fe60 has been of great interest to the nuclear astrophysics community for over a decade. An initial discrepancy between the observed and modeled Galactic Fe60/Al26 ratio motivated numerous studies focused on the nucleosynthesis of these two isotopes, though the cross section of the primary astrophysical production reaction, Fe59(n ,γ)Fe60, has remained purely theoretical. The present work offers a first experimental constraint on the Fe59(n ,γ)Fe60 cross section at astrophysical energies, obtained indirectly via Coulomb dissociation, and demonstrates that the theoretical reaction rates used in present stellar models are not highly erroneous.

  5. Investigation of Microstructure and Mechanical Properties of FeCrC, FeB and FeW Alloys Coated AISI 1020 Steel Using PTA Method

    OpenAIRE

    GÜRGENÇ, TURAN; ÖZEL, Cihan

    2016-01-01

    In this study, surface of AISI 1020 steel was coated by using FeCrC, FeB and FeW ferro alloy powders with plasma transferred arc (PTA) coating method. Ferro alloy powders were blended in chemical composition of (wt.%) 80FeCrC -10FeW-10FeB and AISI 1020 steel surface was coated at two different currents (120A, 160A) and two different travelling speeds (0.1 m/min, 0.15 m/min). The microstructure of the obtained samples were analyzed with optical microscope (OM), scanning electron microscope (SE...

  6. Calidad percibida por dos poblaciones adscritas a dos centros de salud de la provincia de Cuenca

    Directory of Open Access Journals (Sweden)

    Retamal González Antonio

    2000-01-01

    Full Text Available FUNDAMENTO: Para prestar un servicio de calidad es fundamental conocer la opinión que sobre la misma tienen los usuarios del mismo. El objetivo del presente trabajo es medir y comparar la calidad percibida por dos poblaciones asignadas a dos centros de salud de la provincia de Cuenca. MÉTODO: Se trata de un estudio descriptivo transversal. Las Zonas Básicas de Salud estudiadas han sido el Centro de Salud de Cardenete y Centro de Salud de Motilla del Palancar, ambos del Área de Salud de Cuenca. Se ha hecho un muestreo aleatorio estratificado por cuotas de edad y sexo a partir de la tarjeta sanitaria individual. Se ha medido la calidad percibida con un cuestionario validado y fiable, utilizado anteriormente con fines similares por el Ministerio de Sanidad y Consumo. RESULTADOS: Se analizan un total de 295 encuestas, 147 a varones y 148 a mujeres. La media de edad es de 48,83 años (DE: 18,77 para el Centro de Salud de Motilla, en Centro de Salud de Cardenete es de 61,93 años (DE: 15,17. La media de frecuencias mensuales de visitas para Centro de Salud de MP ha sido de 1,56 (DE: 1,91; esta media para el Centro de Salud de Cardenete ha sido:2,49 (DE: 4,27. La media de frecuencias semanales para el Centro de Salud de MP ha sido: 0,32 (DE: 0,66; para el Centro de Salud de Cardenete ha sido: 0,49 (DE: 1,03. El tiempo de espera en el Centro de Salud de MP ha sido: 10,86 minutos (DE: 8,27; en el Centro de Salud de Cardenete: 7,88 (DE: 4,55. 83,4 % de los usuarios de los dos Centros de Salud de conocen la posibilidad de libre elección de médico de cabecera. Se han encontrado diferencias estadísticamente significativas en 11 de los 21 ítems estudiados sobre calidad percibida de que consta el cuestionario CONCLUSIÓN. Los resultados de los componentes de la atención según el análisis factorial de los ítems de calidad percibida son coincidentes con los resultados de calidad percibida. De los dos grupos de usuarios estudiados, los que perciben

  7. Glucogenosis tipo I: reporte de dos casos en dos hermanos de Cartagena de Indias-Colombia

    OpenAIRE

    Alvear-Sedán Ciro; Barboza-Ubarnes, Miryam; Bonillas-Fierro Miguel [q.e.p.d

    2011-01-01

    CASO CLÍNICO: # 1. Producto del primer embarazo de padres no consanguíneos, con lactancia hasta los dos años. A los 18 meses deedad presentó distensión abdominal, hepatomegalia difusa no dolorosa, diarrea de mes y medio, debilidad generalizada, edemaprogresivo en cara y pies, anasarca y anemia. Vesícula, bazo y riñones normales y examen neurológico sin alteraciones. Nopresentó hipoglucemia, ácido láctico normal. Pruebas hepáticas alteradas; colesterol, triglicéridos y ácido úrico en el límite...

  8. ¿DOS CULTURAS O DOS PREJUICIOS? UN APORTE PARA LA COMPRENSION

    Directory of Open Access Journals (Sweden)

    Edelmira Ochoa Camacho

    2015-12-01

    Full Text Available Uno de los propósitos explícitos en el proceso de educar debería ser el favorecer la comprensión de la mirada interdisciplinar del conocimiento, que aporte a la formación de personas integrales, curiosas, críticas e imaginativas (Mendoza, Callejas, Porras y Moralejo 2011, y la universidad juega un papel importante en este aspecto. Por lo que esta investigación busca contribuir al acercamiento de las dos culturas, la humanística y la  científico-tecnológica,  separadas  tradicionalmente  por  los  prejuicios  que  han propiciado la incomprensión y el rechazo hacia los otros.  Esta investigación forma parte del Proyecto de Enseñanza y Aprendizaje sobre la Naturaleza de la Ciencia y la Tecnología (EANCYT. En este trabajo se presentan los resultados globales obtenidos en un curso de Electiva interdisciplinar titulado “Consolidación de la cultura científica” de nivel universitario, donde se aplicó una Secuencia de Enseñanza y Aprendizaje (SEA  denominada “¿Dos culturas o dos prejuicios?”, diseñada por Mendoza et al (2011, que tuvo como uno de los objetivos que los estudiantes interpreten las relaciones entre las ciencias y las humanidades con base en la lectura de textos y la discusión con pares. Antes  y  después  de  la  aplicación  de  la  SEA,  se  aplicó  un  test  a  los  estudiantes estructurado  por    6 cuestiones  pertenecientes  al  Cuestionario  de Opiniones  sobre Ciencia-Tecnología-Sociedad, COCTS (Manassero, Vázquez y Acevedo, 2003. Luego de la aplicación de la SEA se obtuvieron mayores índices (que significan opiniones más adecuadas en las cuestiones referidas a unión de dos culturas, valores y estándares, decisiones sociales, ética e instituciones educativas.

  9. Physical conditions in CaFe interstellar clouds

    OpenAIRE

    Gnacinski, P.; Krogulec, M.

    2007-01-01

    Interstellar clouds that exhibit strong Ca I and Fe I lines were called CaFe clouds. The ionisation equilibrium equations were used to model the column densities of Ca II, Ca I, K I, Na I, Fe I and Ti II in CaFe clouds. The chemical composition of CaFe clouds is that of the Solar System and no depletion of elements onto dust grains is seen. The CaFe clouds have high electron densities n=1 cm^-3 that leads to high column densities of neutral Ca and Fe.

  10. In situ observation of the formation of FeSe

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude; Wulff, Anders Christian; Yue, Zhao

    2011-01-01

    The formation of the FeSe compound from a mixture of Fe and Se powders encased in a composite Cu/Nb sheath was studied in situ by means of high-energy synchrotron x-ray diffraction. Tetragonal beta-FeSe does not seem to form directly from the starting elements. Instead, a sequence of FeSe2, Fe3Se4...... and Fe7Se8 phases formed prior to the main formation stage of beta-FeSe at 350-370 degrees C, although a small amount of this phase appears at 250 degrees C already during a heating ramp of 2 degrees C min(-1). beta-FeSe transforms to delta-FeSe around 480 degrees C and back to beta-FeSe at 405 degrees C...

  11. Buena Alimentacion, Buena Salud: a preventive nutrition intervention in Caribbean Latinos with type 2 diabetes.

    Science.gov (United States)

    Vazquez, I M; Millen, B; Bissett, L; Levenson, S M; Chipkin, S R

    1998-01-01

    A culturally sensitive 3-month intervention was provided to 18 Caribbean Latino men and women with non-insulin-dependent (type 2) diabetes mellitus. Compared to the randomly assigned control group, the intervention group showed statistically significant decreases in total calories, fat calories, percent of calories from fat, saturated fat calories, and percent of calories from saturated fat The intervention group showed increases in calories from carbohydrates and in the percent of calories from fiber.

  12. Fe-deficiency-induced expression of bHLH104 enhances Fe-deficiency tolerance of Arabidopsis thaliana.

    Science.gov (United States)

    Wang, Ce; Yao, Xiani; Yu, Diqiu; Liang, Gang

    2017-04-27

    Expression of bHLH104 - GFP driven by the MYB72 promoter improves plants' tolerance to Fe deficiency and increases seed Fe concentrations. Iron (Fe) deficiency causes reduced crop yield and quality. In humans, Fe deficiency is directly associated with Fe-deficiency anemia. Therefore, breeding Fe-deficiency tolerant and Fe-enriched plants are an ideal approach to deal with these problems. Here, different strategies were explored to generate Fe-deficiency tolerant and Fe-enriched plants. Unexpectedly, the overexpression of Fe-deficiency responsive genes (IRT1, MYB72, and bHLH100) resulted in enhanced sensitivity to Fe deficiency, including leaf chlorosis and short roots under Fe-deficiency conditions. Next, three different types of Fe-deficiency responsive promoters (Pro IRT1 , Pro MYB72, and Pro bHLH100 ) were used to drive the expression of bHLH104-GFP fusion gene in Arabidopsis. Pro IRT1 :bHLH104-GFP plants showed the enhanced sensitivity to Fe deficiency on Fe-deficient media and the reduced fertility in alkaline soil. In contrast, Pro bHLH100 :bHLH104-GFP plants displayed a slight tolerance to Fe deficiency and Pro MYB72 :bHLH104-GFP plants had a significant advantage in growth in alkaline soil, including increased root length, chlorophyll, and biomass. Further analysis revealed that the expression of Fe-deficiency responsive genes was dramatically upregulated in both Pro MYB72 :bHLH104-GFP and Pro bHLH100 :bHLH104-GFP plants under Fe-deficiency conditions. When grown in alkaline soil, Pro MYB72 :bHLH104-GFP plants greatly improved the seed yield and Fe concentration. These results are fundamental for plant manipulation approaches to modify tolerance to Fe deficiency and Fe accumulation through alterations of bHLH104 gene expression.

  13. Siderophores are not involved in Fe(III) solubilization during anaerobic Fe(III) respiration by Shewanella oneidensis MR-1.

    Science.gov (United States)

    Fennessey, Christine M; Jones, Morris E; Taillefert, Martial; DiChristina, Thomas J

    2010-04-01

    Shewanella oneidensis MR-1 respires a wide range of anaerobic electron acceptors, including sparingly soluble Fe(III) oxides. In the present study, S. oneidensis was found to produce Fe(III)-solubilizing organic ligands during anaerobic Fe(III) oxide respiration, a respiratory strategy postulated to destabilize Fe(III) and produce more readily reducible soluble organic Fe(III). In-frame gene deletion mutagenesis, siderophore detection assays, and voltammetric techniques were combined to determine (i) if the Fe(III)-solubilizing organic ligands produced by S. oneidensis during anaerobic Fe(III) oxide respiration were synthesized via siderophore biosynthesis systems and (ii) if the Fe(III)-siderophore reductase was required for respiration of soluble organic Fe(III) as an anaerobic electron acceptor. Genes predicted to encode the siderophore (hydroxamate) biosynthesis system (SO3030 to SO3032), the Fe(III)-hydroxamate receptor (SO3033), and the Fe(III)-hydroxamate reductase (SO3034) were identified in the S. oneidensis genome, and corresponding in-frame gene deletion mutants were constructed. DeltaSO3031 was unable to synthesize siderophores or produce soluble organic Fe(III) during aerobic respiration yet retained the ability to solubilize and respire Fe(III) at wild-type rates during anaerobic Fe(III) oxide respiration. DeltaSO3034 retained the ability to synthesize siderophores during aerobic respiration and to solubilize and respire Fe(III) at wild-type rates during anaerobic Fe(III) oxide respiration. These findings indicate that the Fe(III)-solubilizing organic ligands produced by S. oneidensis during anaerobic Fe(III) oxide respiration are not synthesized via the hydroxamate biosynthesis system and that the Fe(III)-hydroxamate reductase is not essential for respiration of Fe(III)-citrate or Fe(III)-nitrilotriacetic acid (NTA) as an anaerobic electron acceptor.

  14. Fe-Impregnated Mineral Colloids for Peroxide Activation: Effects of Mineral Substrate and Fe Precursor.

    Science.gov (United States)

    Li, Yue; Machala, Libor; Yan, Weile

    2016-02-02

    Heterogeneous iron species at the mineral/water interface are important catalysts for the generation of reactive oxygen species at circumneutral pH. One significant pathway leading to the formation of such species arises from deposition of dissolved iron onto mineral colloids due to changes in redox conditions. This study investigates the catalytic properties of Fe impregnated on silica, alumina, and titania nanoparticles (as prototypical mineral colloids). Fe impregnation was carried out by immersing the mineral nanoparticles in dilute Fe(II) or Fe(III) solutions at pH 6 and 3, respectively, in an aerobic environment. The uptake of iron per unit surface area follows the order of nTiO2 > nAl2O3 > nSiO2 for both types of Fe precursors. Impregnation of mineral particles in Fe(II) solutions results in predominantly Fe(III) species due to efficient surface-mediated oxidation. The catalytic activity of the impregnated solids to produce hydroxyl radical (·OH) from H2O2 decomposition was evaluated using benzoic acid as a probe compound under dark conditions. Invariably, the rates of benzoic acid oxidation with different Fe-laden particles increase with the surface density of Fe until a critical density above which the catalytic activity approaches a plateau, suggesting active Fe species are formed predominantly at low surface loadings. The critical surface density of Fe varies with the mineral substrate as well as the aqueous Fe precursor. Fe impregnated on TiO2 exhibits markedly higher activity than its Al2O3 and SiO2 counterparts. The speciation of interfacial Fe is analyzed with diffuse reflectance UV-vis analysis and interpretation of the data in the context of benzoic oxidation rates suggests that the surface activity of the solids for ·OH generation correlates strongly with the isolated (i.e., mononuclear) Fe species. Therefore, iron dispersed on mineral colloids is a significant form of reactive iron surfaces in the aquatic environment.

  15. Fe biomineralization mirrors individual metabolic activity in a nitrate-dependent Fe(II-oxidizer

    Directory of Open Access Journals (Sweden)

    Jennyfer eMIOT

    2015-09-01

    Full Text Available Microbial biomineralization sometimes leads to periplasmic encrustation, which is predicted to enhance microorganism preservation in the fossil record. Mineral precipitation within the periplasm is however thought to induce death, as a result of permeability loss preventing nutrient and waste transit across the cell wall. This hypothesis had however never been investigated down to the single cell level. Here, we cultured the nitrate reducing Fe(II oxidizing bacteria Acidovorax sp. strain BoFeN1 that have been previously shown to promote the precipitation of a diversity of Fe minerals (lepidocrocite, goethite, Fe phosphate encrusting the periplasm. We investigated the connection of Fe biomineralization with carbon assimilation at the single cell level, using a combination of electron microscopy and Nano-Secondary Ion Mass Spectrometry (NanoSIMS. Our analyses revealed strong individual heterogeneities of Fe biomineralization. Noteworthy, a small proportion of cells remaining free of any precipitate persisted even at advanced stages of biomineralization. Using pulse chase experiments with 13C-acetate, we provide evidences of individual phenotypic heterogeneities of carbon assimilation, correlated with the level of Fe biomineralization. Whereas non- and moderately encrusted cells were able to assimilate acetate, higher levels of periplasm encrustation prevented any carbon incorporation. Carbon assimilation only depended on the level of Fe encrustation and not on the nature of Fe minerals precipitated in the cell wall. Carbon assimilation decreased exponentially with increasing cell-associated Fe content. Persistence of a small proportion of non-mineralized and metabolically active cells might constitute a strategy of survival in highly ferruginous environments. Eventually, our results suggest that periplasmic Fe biomineralization may provide a signature of individual metabolic status, which could be looked for in the fossil record and in modern

  16. Shewanella putrefaciens produces an Fe(III)-solubilizing organic ligand during anaerobic respiration on insoluble Fe(III) oxides.

    Science.gov (United States)

    Taillefert, Martial; Beckler, Jordon S; Carey, Elizabeth; Burns, Justin L; Fennessey, Christine M; DiChristina, Thomas J

    2007-11-01

    The mechanism of Fe(III) reduction was investigated using voltammetric techniques in anaerobic incubations of Shewanella putrefaciens strain 200 supplemented with Fe(III) citrate or a suite of Fe(III) oxides as terminal electron acceptor. Results indicate that organic complexes of Fe(III) are produced during the reduction of Fe(III) at rates that correlate with the reactivity of the Fe(III) phase and bacterial cell density. Anaerobic Fe(III) solubilization activity is detected with either Fe(III) oxides or Fe(III) citrate, suggesting that the organic ligand produced is strong enough to destabilize Fe(III) from soluble or solid Fe(III) substrates. Results also demonstrate that Fe(III) oxide dissolution is not controlled by the intrinsic chemical reactivity of the Fe(III) oxides. Instead, the chemical reaction between the endogenous organic ligand is only affected by the number of reactive surface sites available to S. putrefaciens. This report describes the first application of voltammetric techniques to demonstrate production of soluble organic-Fe(III) complexes by any Fe(III)-reducing microorganism and is the first report of a Fe(III)-solubilizing ligand generated by a metal-reducing member of the genus Shewanella.

  17. [NiFeSe]-hydrogenase chemistry.

    Science.gov (United States)

    Wombwell, Claire; Caputo, Christine A; Reisner, Erwin

    2015-11-17

    The development of technology for the inexpensive generation of the renewable energy vector H2 through water splitting is of immediate economic, ecological, and humanitarian interest. Recent interest in hydrogenases has been fueled by their exceptionally high catalytic rates for H2 production at a marginal overpotential, which is presently only matched by the nonscalable noble metal platinum. The mechanistic understanding of hydrogenase function guides the design of synthetic catalysts, and selection of a suitable hydrogenase enables direct applications in electro- and photocatalysis. [FeFe]-hydrogenases display excellent H2 evolution activity, but they are irreversibly damaged upon exposure to O2, which currently prevents their use in full water splitting systems. O2-tolerant [NiFe]-hydrogenases are known, but they are typically strongly biased toward H2 oxidation, while H2 production by [NiFe]-hydrogenases is often product (H2) inhibited. [NiFeSe]-hydrogenases are a subclass of [NiFe]-hydrogenases with a selenocysteine residue coordinated to the active site nickel center in place of a cysteine. They exhibit a combination of unique properties that are highly advantageous for applications in water splitting compared with other hydrogenases. They display a high H2 evolution rate with marginal inhibition by H2 and tolerance to O2. [NiFeSe]-hydrogenases are therefore one of the most active molecular H2 evolution catalysts applicable in water splitting. Herein, we summarize our recent progress in exploring the unique chemistry of [NiFeSe]-hydrogenases through biomimetic model chemistry and the chemistry with [NiFeSe]-hydrogenases in semiartificial photosynthetic systems. We gain perspective from the structural, spectroscopic, and electrochemical properties of the [NiFeSe]-hydrogenases and compare them with the chemistry of synthetic models of this hydrogenase active site. Our synthetic models give insight into the effects on the electronic properties and reactivity of

  18. Protein profile of Beta vulgaris leaf apoplastic fluid and changes induced by Fe deficiency and Fe resupply

    OpenAIRE

    Ceballos-Laita, Laura; Gutierrez-Carbonell, Elain; Lattanzio, Giuseppe; Vázquez, Saul; Contreras-Moreira, Bruno; Abadía, Anunciación; Abadía, Javier; López-Millán, Ana-Flor

    2015-01-01

    The fluid collected by direct leaf centrifugation has been used to study the proteome of the sugar beet apoplastic fluid as well as the changes induced by Fe deficiency and Fe resupply to Fe-deficient plants in the protein profile. Plants were grown in Fe-sufficient and Fe-deficient conditions, and Fe resupply was carried out with 45 ?M Fe(III)-EDTA for 24 h. Protein extracts of leaf apoplastic fluid were analyzed by two-dimensional isoelectric focusing-SDS-PAGE electrophoresis. Gel image ana...

  19. Protein profile of Beta vulgaris leaf apoplastic fluid and changes induced by Fe deficiency and Fe resupply

    OpenAIRE

    Laura eCeballos-Laita; Elain eGutierrez-Carbonell; Giuseppe eLattanzio; Saul eVázquez; Bruno eContreras-Moreira; Anunciación eAbadía; Javier eAbadía; Ana-Flor eLopez-Millan

    2015-01-01

    The fluid collected by direct leaf centrifugation has been used to study the proteome of the sugar beet apoplastic fluid as well as the changes induced by Fe deficiency and Fe resupply to Fe-deficient plants in the protein profile. Plants were grown in Fe-sufficient and Fe-deficient conditions, and Fe resupply was carried out with 45 μM Fe(III)-EDTA for 24 h. Protein extracts of leaf apoplastic fluid were analyzed by two-dimensional isoelectric focusing-SDS-PAGE electrophoresis. Gel image ana...

  20. A proteção dos deslocados ambientais no regime internacional dos refugiados

    Directory of Open Access Journals (Sweden)

    Andrea Pacheco Pacífico

    Full Text Available O deslocamento de pessoas por causas ambientais gera discussões pela ausência de reconhecimento legal e proteção jurídica específica para essa categoria de pessoas. Assim, este artigo examina o Regime Internacional dos Refugiados (RIR, conceitua deslocados ambientais (DA e reflete sobre a ausência de proteção pelo RIR. Em seguida, examina as causas e as consequências dos deslocamentos e as formas de proteção aos DA, concluindo que os regimes vigentes não lhes oferecem proteção efetiva. Uma solução, segundo Betts (2009, seria cooperação para proteção por persuasão via cruzamento de assuntos de interesse estatal, persuadindo Estados a cooperarem em seus interesses, como saída eficaz para a ausência de proteção efetiva aos DA.

  1. Homem dos lobos: a atualidade dos casos clínicos freudianos

    Directory of Open Access Journals (Sweden)

    Marcus André Vieira

    Full Text Available Em que interessa hoje para o psicólogo clínico ou o psicanalista a leitura dos relatos clínicos de Freud? Para além de uma leitura obrigatória que deve constar em suas estantes, é preciso que algo que suscite sua prática esteja em jogo. Freud situa em seus relatos o que primeiramente é conceituado por Lacan como sujeito, puro furo, ponto onde culminam as linhas mestras de uma vida, o qual delimitaria o ponto extremo de singularidade. Posteriormente, Lacan propõe a delimitação desse furo como objeto, nomeia-o objeto a e propõe que essa extração seja o resultado da operação analítica. Trata-se de situar o modo como o caso do Homem dos Lobos pode auxiliar no entendimento dessas difíceis proposições.

  2. O valor da moeda e a teoria dos preços dos ativos

    Directory of Open Access Journals (Sweden)

    Fernando de Holanda Barbosa

    2005-06-01

    Full Text Available Este artigo usa o enfoque da teoria dos preços dos ativos na determinação do preço da moeda para apresentar uma resenha concisa sobre os seguintes tópicos da teoria monetária: i preço da moeda: bolhas versus fundamentos; ii equilíbrio múltiplo; iii indeterminação do nível de preço ; iv quantidade ótima de moeda ; v hiperinflação; vi substituição de moeda e vii rigidez do preço no curto prazo.The price of money, as the price of any financial asset, can be determined through asset pricing theory. Based on this approach, this paper presents a concise survey of the following topics of monetary theory: i price of money: bubbles versus fundamentals; ii multiple equilibria; iii price level indeterminacy; iv optimum quantity of money; v hyperinflation; vi currency substitution, and vii price of money rigidity.

  3. John dos Passos in the 1930s John dos Passos in the 1930s

    Directory of Open Access Journals (Sweden)

    Townsend Ludington

    2008-04-01

    Full Text Available In 1930 John dos Passos was nearing the pinnacle of his impressive career. The Forty Second Parallel, the first volume of his trilogy USA, would be published that year to critical acclaim; he was respected as a writer by political factions both left and right; he was actively involved in causes in which he believed such as Emergency Committee for the Southern Political Prisoners (the Scottsboro Boys; and he was newly and happily married to Katy Smith and enjoying his friendships with other literary lights such as Ernest Hemingway. In 1930 John dos Passos was nearing the pinnacle of his impressive career. The Forty Second Parallel, the first volume of his trilogy USA, would be published that year to critical acclaim; he was respected as a writer by political factions both left and right; he was actively involved in causes in which he believed such as Emergency Committee for the Southern Political Prisoners (the Scottsboro Boys; and he was newly and happily married to Katy Smith and enjoying his friendships with other literary lights such as Ernest Hemingway.

  4. MOBILIDADE ESPACIAL DOS IMIGRANTES ESTRANGEIROS NO BRASIL - 1991/2010

    Directory of Open Access Journals (Sweden)

    Weber Soares

    Full Text Available Resumo Na formação do território brasileiro, os fluxos migratórios internacionais e internos desempenharam papel central. Se as correntes de imigrantes oriundas da África e da Europa fomentaram as atividades econômicas do passado, as novas ondas migratórias, a contar de meados do século XX, conformaram a dinâmica socioespacial brasileira mais recente. Ao lado de tradicionais destinos como o Japão e Estados Unidos, novos movimentos populacionais internos à América do Sul ganharam importância, incluindo os fluxos de entrada no território brasileiro. Em face dessa dinâmica migratória, constitui objetivo principal deste trabalho o levantamento das diferentes nacionalidades dos imigrantes estrangeiros residentes no Brasil e a análise das diferenças na mobilidade espacial interna desses mesmos estrangeiros. De acordo com dados extraídos dos censos demográficos de 1991, 2000 e 2010, nota-se uma expressiva expansão do número de estrangeiros naturais dos países latino-americanos em terras brasileiras, em especial dos vizinhos do cone sul, e um significativo nível de mobilidade espacial interna dos paraguaios e dos bolivianos.

  5. Fe-Mo double perovskite: From small clusters to bulk material

    Energy Technology Data Exchange (ETDEWEB)

    Carvajal, E., E-mail: ecarvajalq@ipn.mx [Instituto Politecnico Nacional, ESIME-Culhuacan, Av. Santa Ana 1000, C.P. 04430 Mexico, D.F. (Mexico); Oviedo-Roa, R. [Programa de Investigacion en Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas Norte 152, 07730 Mexico, D.F. (Mexico); Cruz-Irisson, M. [Instituto Politecnico Nacional, ESIME-Culhuacan, Av. Santa Ana 1000, C.P. 04430 Mexico, D.F. (Mexico); Navarro, O. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, A.P. 70-360, 04510 Mexico, D.F. (Mexico)

    2012-09-20

    To understand the differences in behaviour between up- and down-spin electrons observed in the half-metallic Sr{sub 2}FeMoO{sub 6} double perovskite, the density of states (DOS) was studied for the (FeO{sub 6}){sup -4} and (MoO{sub 6}){sup -6} octahedral clusters using first-principles density functional theory within the generalised gradient approximation (GGA) scheme and the Perdew-Burke-Ernzerhof (PBE) functional. Our results reveal that half-metallic character is present, even starting from an isolated (FeO{sub 6}){sup -4} cluster, and is a consequence of spin decoupling of antibonding hybridisations between iron t{sub 2g} states and oxygen p states (t{sub 2g}{sup a} states), i.e., t{sub 2g}{sup a} states lie below the Highest Occupied Molecular Orbital (HOMO) in the up-spin channel, whereas they lie above the HOMO level in the down-spin channel. The spin-induced shifting between up-spin and down-spin DOS situates the HOMO in such a way that the molecular orbitals oxygen p states (p bands) are fully spin-paired by octet electrons. Thus, the down-spin channel has metallic character because the HOMO lies just at the p bands, and the up-spin channel is semiconducting because the HOMO falls within the energy gap between the t{sub 2g}{sup a} and e{sub g}{sup a} bands. Finally, the (MoO{sub 6}){sup -6} octahedron does not inhibit the perovskite half-metallic character since this cluster has a zero total spin.

  6. Magnetic properties of ball-milled TbFe2 and TbFe2B

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 27; Issue 2. Magnetic properties of ... Amorphous materials; intermetallic compounds; magnetic materials; magnetic properties. Abstract. The magnetic properties of ball-milled TbFe2 and TbFe2B were studied by magnetization measurements. X-ray diffraction studies on ...

  7. Magnetic structure of molecular magnet Fe [Fe (CN) 6]· 4H2O

    Indian Academy of Sciences (India)

    We have studied the magnetic structure of Fe[Fe(CN)6]·4H2O, prepared by precipitation method, using neutron diffraction technique. Temperature dependent DC magnetization study down to 4.2 K shows that the compound undergoes from a high temperature disordered (paramagnetic) to an ordered magnetic phase ...

  8. Magnetic structure of molecular magnet Fe[Fe(CN)6]·4H2O

    Indian Academy of Sciences (India)

    perature disordered (paramagnetic) to an ordered magnetic phase transition at 22.6 K. Rietveld analysis of neutron diffraction pattern at 60 K (in its paramagnetic phase) re- vealed a face centred cubic structure with space group Fm3m. The structure contains three-dimensional network of straight Fe3+–C≡N–Fe3+ chains ...

  9. Photocatalytic hydrogen evolution by [FeFe] hydrogenase mimics in homogeneous solution.

    Science.gov (United States)

    Wang, Wen-Guang; Wang, Feng; Wang, Hong-Yan; Si, Gang; Tung, Chen-Ho; Wu, Li-Zhu

    2010-08-02

    To mimic [FeFe] hydrogenases (H(2)ases) in nature, molecular photocatalysts 1 a, 1 b, and 1 c anchoring rhenium(I) complex S to one of the iron cores of [FeFe]-H(2)ases model complex C, have been constructed for H(2) generation by visible light in homogeneous solution. The time-dependence of H(2) evolution and a spectroscopic study demonstrate that the orientation of S and the specific bridge in 1 a, 1 b, and 1 c are important both for the electron-transfer step from the excited S* to the catalytic C, and the formation of unprecedented long-lived charge separation for 1 a (780 micros), 1 b, and 1 c (>2 ms) in [FeFe]-H(2)ases mimics. The fast forward electron-transfer step from the excited S* to the catalytic C but the slow back electron-transfer step of the charge-recombination in the designed photocatalysts 1 a, 1 b, and 1 c are reminiscent of the behavior of [FeFe]-H(2)ases in nature.

  10. Photocatalytic hydrogen production from a simple water-soluble [FeFe]-hydrogenase model system.

    Science.gov (United States)

    Cao, Wei-Ning; Wang, Feng; Wang, Hong-Yan; Chen, Bin; Feng, Ke; Tung, Chen-Ho; Wu, Li-Zhu

    2012-08-21

    Combined with a simple water soluble [FeFe]-hydrogenase mimic 1, Ru(bpy)(3)(2+) and ascorbic acid enable hydrogen production photocatalytically. More than 88 equivalents of H(2) were achieved in water, which is much better than that obtained in an organic solvent or a mixture of organic solvent and water.

  11. A synthetic system links FeFe-hydrogenases to essential E. coli sulfur metabolism

    Directory of Open Access Journals (Sweden)

    Grandl Gerald

    2011-05-01

    Full Text Available Abstract Background FeFe-hydrogenases are the most active class of H2-producing enzymes known in nature and may have important applications in clean H2 energy production. Many potential uses are currently complicated by a crucial weakness: the active sites of all known FeFe-hydrogenases are irreversibly inactivated by O2. Results We have developed a synthetic metabolic pathway in E. coli that links FeFe-hydrogenase activity to the production of the essential amino acid cysteine. Our design includes a complementary host strain whose endogenous redox pool is insulated from the synthetic metabolic pathway. Host viability on a selective medium requires hydrogenase expression, and moderate O2 levels eliminate growth. This pathway forms the basis for a genetic selection for O2 tolerance. Genetically selected hydrogenases did not show improved stability in O2 and in many cases had lost H2 production activity. The isolated mutations cluster significantly on charged surface residues, suggesting the evolution of binding surfaces that may accelerate hydrogenase electron transfer. Conclusions Rational design can optimize a fully heterologous three-component pathway to provide an essential metabolic flux while remaining insulated from the endogenous redox pool. We have developed a number of convenient in vivo assays to aid in the engineering of synthetic H2 metabolism. Our results also indicate a H2-independent redox activity in three different FeFe-hydrogenases, with implications for the future directed evolution of H2-activating catalysts.

  12. Diffusivity of Al and Fe near the diffusion bonding interface of Fe3Al ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 28; Issue 1. Diffusivity of Al and Fe near the diffusion bonding interface of Fe3Al with low carbon steel. Li Yajiang Wang Juan Yin Yansheng Ma Haijun. Alloys and Steels Volume 28 Issue 1 February 2005 pp 69-74 ...

  13. Modeling the active site of [FeFe]-hydrogenase: Electro-catalytic ...

    Indian Academy of Sciences (India)

    Electro-catalytic hydrogen evaluation studies (from acetic acid) have been performed using com- pounds 1–6 as electro-catalysts. The mechanistic aspects of relevant electro–catalytic proton reductions have been discussed in detail. Keywords. Modeling the active site; [FeFe]-hydrogenase; spectroscopy; electrocatalytic ...

  14. Fabrication and magnetic properties of Fe/GaAs/Fe hybrid structures

    NARCIS (Netherlands)

    Wong, P.K.J.; Zhang, W.; Zhang, W.; Wu, J.; Will, I.G.; Xu, Y.B.; Farrer, I.; Ritchie, D.A.

    2010-01-01

    In this contribution, experimental results on the fabrication and magnetic characterization of a novel type vertical Fe/GaAs(100)/Fe spin-valve (SV) spintronic device are presented. An array of techniques has been developed by combining use of ex-situ chemical and selective etching of

  15. Diffusivity of Al and Fe near the diffusion bonding interface of Fe3Al ...

    Indian Academy of Sciences (India)

    Unknown

    Diffusivity of Al and Fe near the diffusion bonding interface of Fe3Al with low carbon steel. LI YAJIANG*†, WANG JUAN†, YIN YANSHENG† and MA HAIJUN†. *Key Lab of Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061, China. †National Key Lab of Advanced Welding ...

  16. Fe and N diffusion in nitrogen-rich FeN measured using neutron ...

    Indian Academy of Sciences (India)

    Fe and N diffusion in nitrogen-rich FeN measured using neutron reflectometry. MUKUL GUPTA1,∗, A GUPTA2, A WILDES3 and T GUTBERLET4. 1UGC-DAE Consortium for Scientific Research, R-5 Shed, Bhabha Atomic Research. Centre, Mumbai 400 085, India. 2UGC-DAE Consortium for Scientific Research, Khandwa ...

  17. Fe(II) oxidation kinetics and Fe hydroxyphosphate precipitation upon aeration of anaerobic (ground)water

    NARCIS (Netherlands)

    van der Grift, B.|info:eu-repo/dai/nl/373433484; Griffioen, J.|info:eu-repo/dai/nl/091129265; Behrends, T.|info:eu-repo/dai/nl/30484358X; Wassen, M.J.|info:eu-repo/dai/nl/07165710X; Schot, P.P.|info:eu-repo/dai/nl/08071563X; Osté, Leonard

    2015-01-01

    Exfiltration of anaerobic Fe-rich groundwater into surface water plays an important role in controlling the transport of phosphate (P) from agricultural areas to the sea. Previous laboratory and field studies showed that Fe(II) oxidation upon aeration leads to effective immobilization of dissolved P

  18. Adhesive and Cohesive Strength in FeB/Fe2B Systems

    Science.gov (United States)

    Meneses-Amador, A.; Blancas-Pérez, D.; Corpus-Mejía, R.; Rodríguez-Castro, G. A.; Martínez-Trinidad, J.; Jiménez-Tinoco, L. F.

    2018-01-01

    In this work, FeB/Fe2B systems were evaluated by the scratch test. The powder-pack boriding process was performed on the surface of AISI M2 steel. The mechanical parameters, such as yield stress and Young's modulus of the boride layer, were obtained by the instrumented indentation technique. Residual stresses produced on the boride layer were estimated by using the x-ray diffraction (XRD) technique. The scratch test was performed in order to evaluate the cohesive/adhesive strength of the FeB/Fe2B coating. In addition, a numerical evaluation of the scratch test on boride layers was performed by the finite element method. Maximum principal stresses were related to the failure mechanisms observed by the experimental scratch test. Shear stresses at the interfaces of the FeB/Fe2B/substrate system were also evaluated. Finally, the results obtained provide essential information about the effect of the layer thickness, the residual stresses, and the resilience modulus on the cohesive/adhesive strength in FeB/Fe2B systems.

  19. Thermoelectricity and disorder of FeCo/MgO/FeCo magnetic tunnel junctions

    NARCIS (Netherlands)

    Wang, S.Z.; Xia, K.; Bauer, G.E.W.

    2014-01-01

    We compute the thermoelectric transport parameterized by the Seebeck coefficient and thermal/electric conductance of random-alloy FeCo/MgO/FeCo(001) magnetic tunnel junctions (MTJs) from first principles using a generalized Landauer-Büttiker formalism. The thermopower is found to be typically

  20. Green synthesis of Fe0 and bimetallic Fe0 for oxidative catalysis and reduction applications

    Science.gov (United States)

    A single-step green approach to the synthesis of nanoscale zero valent iron (nZVI) and nanoscale bimetallic (Fe0/Pd) particles using tea (Camellia sinensis) polyphenols is described. The expedient reaction between polyphenols and ferric chloride (FeCl3) occurs within a minute at ...

  1. A cell-free microtiter plate screen for improved [FeFe] hydrogenases.

    Directory of Open Access Journals (Sweden)

    James A Stapleton

    Full Text Available BACKGROUND: [FeFe] hydrogenase enzymes catalyze the production and dissociation of H(2, a potential renewable fuel. Attempts to exploit these catalysts in engineered systems have been hindered by the biotechnologically inconvenient properties of the natural enzymes, including their extreme oxygen sensitivity. Directed evolution has been used to improve the characteristics of a range of natural catalysts, but has been largely unsuccessful for [FeFe] hydrogenases because of a lack of convenient screening platforms. METHODOLOGY/PRINCIPAL FINDINGS: Here we describe an in vitro screening technology for oxygen-tolerant and highly active [FeFe] hydrogenases. Despite the complexity of the protocol, we demonstrate a level of reproducibility that allows moderately improved mutants to be isolated. We have used the platform to identify a mutant of the Chlamydomonas reinhardtii [FeFe] hydrogenase HydA1 with a specific activity approximately 4 times that of the wild-type enzyme. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate the feasibility of using the screen presented here for large-scale efforts to identify improved biocatalysts for energy applications. The system is based on our ability to activate these complex enzymes in E. coli cell extracts, which allows unhindered access to the protein maturation and assay environment.

  2. Fe hydroxyphosphate precipitation and Fe(II) oxidation kinetics upon aeration of Fe(II) and phosphate-containing synthetic and natural solutions

    Science.gov (United States)

    van der Grift, B.; Behrends, T.; Osté, L. A.; Schot, P. P.; Wassen, M. J.; Griffioen, J.

    2016-08-01

    Exfiltration of anoxic Fe-rich groundwater into surface water and the concomitant oxidative precipitation of Fe are important processes controlling the transport of phosphate (PO4) from agricultural areas to aquatic systems. Here, we explored the relationship between solution composition, reaction kinetics, and the characteristics of the produced Fe hydroxyphosphate precipitates in a series of aeration experiments with anoxic synthetic water and natural groundwater. A pH stat device was used to maintain constant pH and to record the H+ production during Fe(II) oxidation in the aeration experiments in which the initial aqueous P/Fe ratios ((P/Fe)ini), oxygen concentration and pH were varied. In general, Fe(II) oxidation proceeded slower in the presence of PO4 but the decrease of the PO4 concentration during Fe(II) oxidation due to the formation of Fe hydroxyphosphates caused additional deceleration of the reaction rate. The progress of the reaction could be described using a pseudo-second-order rate law with first-order dependencies on PO4 and Fe(II) concentrations. After PO4 depletion, the Fe(II) oxidation rates increased again and the kinetics followed a pseudo-first-order rate law. The first-order rate constants after PO4 depletion, however, were lower compared to the Fe(II) oxidation in a PO4-free solution. Hence, the initially formed Fe hydroxyphosphates also affect the kinetics of continuing Fe(II) oxidation after PO4 depletion. Presence of aqueous PO4 during oxidation of Fe(II) led to the formation of Fe hydroxyphosphates. The P/Fe ratios of the precipitates ((P/Fe)ppt) and the recorded ratio of H+ production over decrease in dissolved Fe(II) did not change detectably throughout the reaction despite a changing P/Fe ratio in the solution. When (P/Fe)ini was 0.9, precipitates with a (P/Fe)ppt ratio of about 0.6 were formed. In experiments with (P/Fe)ini ratios below 0.6, the (P/Fe)ppt decreased with decreasing (P/Fe)ini and pH value. Aeration experiments with

  3. Magnetorheological Payne effect in bidisperse MR fluids containing Fe nanorods and Fe3O4 nanospheres: a dynamic rheological study

    OpenAIRE

    Arief, Injamamul; Mukhopadhyay, P. K.

    2015-01-01

    The spherical Fe3O4 with 300 nm in diameter was synthesized by typical thermal decomposition of Fe (III) organo-metallic precursor in polyol and polyacrylic acid. Fe-nanorods were prepared by reducing Fe (III) nitrate in presence of polyol-hydrazine-CTAB. Morphology and magnetic characterization of the nanoparticles were performed by ESEM, XRD and VSM studies. We performed detailed non-linear magnetorheological properties of three MR fluids (10 vol%) containing isotropic Fe3O4 and anisotropic...

  4. N-Derivatives of peri-Substituted Dichalcogenide [FeFe]-Hydrogenase Mimics: Towards Photocatalytic Dyads for Hydrogen Production

    OpenAIRE

    Figliola, Carlotta; Male, Louise; Horswell, Sarah,; Grainger, Richard,

    2015-01-01

    International audience; Synthetic strategies towards molecular dyads based on peri-substituted dichalcogenide (S,Se) [FeFe]-hydrogenase synthetic mimics covalently linked to a ZnTPP photosensitizer are described. Dithiolate and diselenolate model systems 2–5 are prepared through condensation of 2-naphthaldehydes with p-methoxyaniline, reduction of the resulting Schiff base and oxidative insertion of Fe2(CO)6 into the dichalcogen bond of the imine or amine. Diselenolate-based [FeFe] complexes ...

  5. Memória e actualidade dos movimentos estudantis

    Directory of Open Access Journals (Sweden)

    Elísio Estanque

    2012-10-01

    Full Text Available Os movimentos estudantis dos anos sessenta têm continuado a suscitar recorrentes polémicas. A evocação-celebração dos quarenta anos volvidos sobre o Maio de 68 em França apenas veio dar-lhes uma maior projecção. Mas falar dos anos sessenta a propósito do movimento estudantil não significa, naturalmente, que nos fiquemos por um registo meramente descritivo e menos ainda que se privilegiem olhares melancólicos sobre esse passado. Mais do que revisitar as divergências entre os “nostálgicos” que ...

  6. Coercivity enhancement of (Nd,Ce)-Fe-B sintered magnets by doping Nd-Fe additives

    Science.gov (United States)

    Chen, K.; Guo, S.; Fan, X. D.; Ding, G. F.; Di, J. H.; Chen, R. J.; Lee, D.; Yan, A. R.

    2017-02-01

    The effect of Nd-Fe additives on magnetic properties and microstructure in (Nd,Ce)-Fe-B sintered magnet has been investigated. By doping 3wt% Nd-Fe additives, the coercivity of the magnet increases from 10.56kOe to 12.69kOe with slight remanence decrease. Microstructure observation reveals that the volume fraction of the grain boundary phase increases accompanying with the thickening of the thin grain boundary between the adjacent grains. The RE6Fe13Cu phase which has low melting temperature develops at the triple junction position and the out shell of the matrix grains get magnetically hardened with 3wt% Nd-Fe additives. The results of the dynamic magnetic domains between the original magnet and processed magnet elucidate that the formation of reversed magnetic domains are more difficult for the processed magnet which is the direct evidence to clarify the coercivity enhancement.

  7. Coercivity enhancement of (Nd,Ce-Fe-B sintered magnets by doping Nd-Fe additives

    Directory of Open Access Journals (Sweden)

    K. Chen

    2017-02-01

    Full Text Available The effect of Nd-Fe additives on magnetic properties and microstructure in (Nd,Ce-Fe-B sintered magnet has been investigated. By doping 3wt% Nd-Fe additives, the coercivity of the magnet increases from 10.56kOe to 12.69kOe with slight remanence decrease. Microstructure observation reveals that the volume fraction of the grain boundary phase increases accompanying with the thickening of the thin grain boundary between the adjacent grains. The RE6Fe13Cu phase which has low melting temperature develops at the triple junction position and the out shell of the matrix grains get magnetically hardened with 3wt% Nd-Fe additives. The results of the dynamic magnetic domains between the original magnet and processed magnet elucidate that the formation of reversed magnetic domains are more difficult for the processed magnet which is the direct evidence to clarify the coercivity enhancement.

  8. Iron Atom Exchange between Hematite and Aqueous Fe(II).

    Science.gov (United States)

    Frierdich, Andrew J; Helgeson, Maria; Liu, Chengshuai; Wang, Chongmin; Rosso, Kevin M; Scherer, Michelle M

    2015-07-21

    Aqueous Fe(II) has been shown to exchange with structural Fe(III) in goethite without any significant phase transformation. It remains unclear, however, whether aqueous Fe(II) undergoes similar exchange reactions with structural Fe(III) in hematite, a ubiquitous iron oxide mineral. Here, we use an enriched (57)Fe tracer to show that aqueous Fe(II) exchanges with structural Fe(III) in hematite at room temperature, and that the amount of exchange is influenced by particle size, pH, and Fe(II) concentration. Reaction of 80 nm-hematite (27 m(2) g(-1)) with aqueous Fe(II) at pH 7.0 for 30 days results in ∼5% of its structural Fe(III) atoms exchanging with Fe(II) in solution, which equates to about one surface iron layer. Smaller, 50 nm-hematite particles (54 m(2) g(-1)) undergo about 25% exchange (∼3× surface iron) with aqueous Fe(II), demonstrating that structural Fe(III) in hematite is accessible to the fluid in the presence of Fe(II). The extent of exchange in hematite increases with pH up to 7.5 and then begins to decrease as the pH progresses to 8.0, likely due to surface site saturation by sorbed Fe(II). Similarly, when we vary the initial amount of added Fe(II), we observe decreasing amounts of exchange when aqueous Fe(II) is increased beyond surface saturation. This work shows that Fe(II) can catalyze iron atom exchange between bulk hematite and aqueous Fe(II), despite hematite being the most thermodynamically stable iron oxide.

  9. ENSEÑAR Y APRENDER CON TECNOLOGÍAS: UN MODELO TEÓRICO PARA LAS BUENAS PRÁCTICAS EDUCATIVAS CON TIC TEACHING AND LEARNING WITH TECHNOLOGY: A THEORETICAL MODEL FOR GOOD EDUCATIONAL PRACTICES WITH ICT

    Directory of Open Access Journals (Sweden)

    Jesús Valverde Berrocoso

    2010-02-01

    Full Text Available Este artículo tiene como objetivo definir un marco teórico explicativo de la integración de las tecnologías de la información y la comunicación (TIC en el sistema educativo, desde la perspectiva de la formación del profesorado. Esta formación inicial y continua de los docentes se caracteriza por una tendencia hacia la “esencialización” de la tecnología y la generación de usuarios que no suelen reflexionar sobre los usos educativos de la propia tecnología en contextos flexibles y variables. Nuestra investigación sobre la integración de las TIC en las aulas nos ha permitido observar la falta de conexión entre los usos personales y profesionales de los profesores de estas herramientas tecnológicas, así como la necesidad de que su formación se oriente hacia el desarrollo de conocimientos y habilidades para examinar, de manera crítica, las implicaciones educativas de estos nuevos medios didácticos. Partimos de la propuesta de Koehler y Mishra (2005; 2006; 2007 y 2008 denominada TPCK (Technological Pedagogical Content Knowledge que se fundamenta en el constructo PCK de Shulman (1987 al que se añade el concepto de “Tecnología” (T, a los de “Pedagogía” (P y “Contenido Curricular” (C. Las conexiones e interacciones dinámicas entre estos tres componentes esenciales da lugar a diferentes componentes que han de ser considerados en la comprensión de los procesos de integración de las TIC en los centros educativos. Las buenas prácticas educativas con TIC son acciones complejas y multidimensionales que exigen (1 comprender la representación y formulación de conceptos y procedimientos para su comprensión a través de las TIC; (2 desarrollar estrategias didácticas constructivistas que usen las TIC para la enseñanza de contenidos curriculares; (3 conocer las dificultades en el aprendizaje de conceptos y de qué forma las TIC pueden ayudar a superarlas y (4 conocer el conocimiento previo de los alumnos, así como la

  10. Chemical consequences of the nuclear reactions 58Fe(n,γ)59Fe and 57Co(EC)57Fe in soluble Prussian Blue

    DEFF Research Database (Denmark)

    Fenger, Jes; Maddock, A. G.; Siekierska, K. E.

    1970-01-01

    KFe[Fe(CN)6],H2O was prepared with 58Fe in either the cation or the complex, and both samples were neutron-irradiated and analysed for free and complexed 59Fe. Parallel experiments were performed on K4[Fe(CN)6],3H2O. In Prussian Blue the retention in the hexacyano-complex is ca. 5% and can be inc...

  11. Synthesis of magnetically exchange coupled SrFe12O19/FeCo composites through cryogenic ball milling

    Science.gov (United States)

    Pang, Ning; Ye, Feng; Jiang, Ying

    2017-07-01

    SrFe12O19/FeCo composite particles with different mass ratios of SrFe12O19 to FeCo were synthesized through a cryogenic ball milling process. The corresponding products were characterized with scanning electron microscopy (SED), transmission electron microscopy (TEM), x-ray diffraction (XRD) and vibrating sample magnetometer (VSM) for crystal morphology, elemental distribution, crystal phases, and magnetic properties. The results showed that when the mass percentage of FeCo was less than 15%, smooth magnetic hysteresis loops could be obtained from SrFe12O19/FeCo composite particles, indicating effective magnetic exchange coupling between the SrFe12O19 and FeCo particles. A further FeCo mass increase resulted in kinks in the magnetic hysteresis loop and destroyed the magnetic exchange coupling. As a comparison, room temperature ball milling of SrFe12O19/FeCo (95/5 wt%) cannot achieve magnetic exchange coupling between SrFe12O19 and FeCo due to FeCo nanoparticle agglomeration.

  12. Substituent effect of Fe(β-diketonate)3 on the control of self-assembly FePt-based nanoparticles

    Science.gov (United States)

    Chokprasombat, K.; Harding, P.; Sirisathitkul, C.; Tangwatanakul, W.; Pinitsoontorn, S.; Muneesawang, P.

    2014-06-01

    Three Fe(β-diketonate)3 compounds namely Fe(tmhd)3 (tmhd = 2,2,6,6-tetramethyl-3,5-heptanedionato), Fe(hfac)3 (hfac = hexafluoroacetylaceto), and Fe(dbm)3 (dbm = dibenzoylmethane) were used as substitutes to Fe(acac)3 (acac = acetyleacetonate) in the synthesis of FePt nanoparticles. The obtained superparamagnetic nanoparticles are 4-5 nm in diameter without showing a large size variation with substituent Fe(β-diketonate)3. The synchrotron X-ray absorption spectroscopy confirmed the energy dispersive spectroscopy that as-synthesized nanoparticles were composed of iron oxides and metallic FePt3 alloys. By employing Fe(hfac)3, the Fe fraction was reduced and the magnetization was modest. The use of Fe(dbm)3 as starting materials gave rise to densely packed FePt3/Fe2O3 heterodimers. The replacements of Fe(acac)3 by Fe(tmhd)3 led to the long-range order of nanoparticle assembly with the narrowest size distribution.

  13. Electrodeposited NiFeCu/Cu multilayers: Effect of Fe ion concentration on properties

    Energy Technology Data Exchange (ETDEWEB)

    Kuru, Hilal, E-mail: htopcu@balikesir.edu.tr [Physics Department, Science and Literature Faculty, Balikesir University, Balikesir 10145 (Turkey); Kockar, Hakan, E-mail: hkockar@balikesir.edu.tr [Physics Department, Science and Literature Faculty, Balikesir University, Balikesir 10145 (Turkey); Alper, Mursel, E-mail: malper@uludag.edu.tr [Physics Department, Science and Literature Faculty, Uludag University, Gorukle, Bursa 16059 (Turkey)

    2015-01-01

    A series of 125[NiFeCu(3 nm)/Cu(1 nm)] multilayers were electrodeposited on strong (110) textured Cu substrates from electrolytes containing different Fe ion concentrations under potentiostatic control. The compositional analysis by energy dispersive X-ray spectroscopy demonstrated that as the Fe ion concentration in the electrolyte is increased, the Fe content of the multilayers increased. X-ray diffraction measurements indicated that all samples exhibited a face-centred cubic structure with a strong (110) texture as their substrates. The surface images obtained by scanning electron microscopy disclosed that all films have smooth surfaces. Magnetoresistance measurements were carried out at room temperature with magnetic fields up to ±12 kOe. All samples exhibited giant magnetoresistance (GMR) and the maximum GMR value of 5% was obtained in the multilayer grown from the electrolyte containing 0.0036 M Fe ion concentration. The GMR magnitude changed depending on the film contents arising from the variation of the Fe ion concentration in the electrolyte. The magnetic properties studied with the vibrating sample magnetometer showed that the saturation magnetisation changed, and the coercivities decreased with varying Fe ion concentration in the electrolyte. The changes observed in the properties were ascribed to the variations observed in the film composition caused by the Fe ion concentration of the electrolyte. - Highlights: • NiFeCu/Cu multilayers were potentiostatically electrodeposited on Cu substrates. • All films had a face-centred cubic structure irrespective of the film content. • All samples exhibited GMR and the maximum GMR value was 5%. • The saturation magnetisation changed, and the coercivities decreased with varying Fe ion concentration in the electrolyte.

  14. Inés Palou: dos novelas y un suicidio

    Directory of Open Access Journals (Sweden)

    Alberto Sánchez

    2009-12-01

    Full Text Available No sabemos muy bien si su experiencia carcelaria cambió para mal la forma de ser de Inés Palou (Agramunt, Lérida, 1923 – Gelida, Barcelona, 1975 o si, por el contrario, eligió el delito como forma de vida con anterioridad. En cualquier caso, su primera nove- la, Carne apaleada, es, o pretende ser, una autobiografía exculpatoria. Sobre su biografía real algo nos dicen los textos que acompañan a la edición de sus obras: Nació en una familia de clase media que pudo pagarle estudios de Comercio y Peritaje Mer- cantil. Su educación familiar fue la misma que solían recibir hace cuarenta o cincuenta años las hijas de buena familia. Desempeñó diversos oficios relacionados con sus estudios hasta que siendo responsable en parte de la marcha financiera de una empresa se vio envuelta en problemas fiscales. Para salir del paso recurrió a métodos que la justicia consideró delictivos, por lo que pasó una larga temporada en la cárcel de mujeres de Barcelona. Allí comenzó a escribir. Y allí comenzaría también el terrible túnel de humillaciones y rebeldía del que sólo salió con el suicidio en 1975.

  15. Presence of 60Fe in eucrite Piplia Kalan: A new perspective to the initial 60Fe/ 56Fe in the early solar system

    Digital Repository Service at National Institute of Oceanography (India)

    Rudraswami, N.G.; Sahijpal, S.; Bhandari, N.

    ) in the early solar system, which is significantly lower than the value inferred from Fe-Ni isotope measurements of chondrules in silicates and sulphides from unequilibrated ordinary chondrites. We attribute the difference in the initial sup(60)Fe/ sup(56) Fe...

  16. Exchange-coupled fct-FePd/α-Fe nanocomposite magnets converted from Pd/Fe3O4 core/shell nanoparticles.

    Science.gov (United States)

    Liu, Fei; Dong, Yunhe; Yang, Wenlong; Yu, Jing; Xu, Zhichuan; Hou, Yanglong

    2014-11-10

    We report the controlled synthesis of exchange-coupled face-centered tetragonal (fct) FePd/α-Fe nanocomposite magnets with variable Fe concentration. The composite was converted from Pd/Fe3O4 core/shell nanoparticles through a high-temperature annealing process in a reducing atmosphere. The shell thickness of core/shell Pd/Fe3O4 nanoparticles could be readily tuned, and subsequently the concentration of Fe in nanocomposite magnets was controlled. Upon annealing reduction, the hard magnetic fct-FePd phase was formed by the interdiffusion between reduced α-Fe and face-centered cubic (fcc) Pd, whereas the excessive α-Fe remained around the fct-FePd grains, realizing exchange coupling between the soft magnetic α-Fe and hard magnetic fct-FePd phases. Magnetic measurements showed variation in the magnetic properties of the nanocomposite magnets with different compositions, indicating distinct exchange coupling at the interfaces. The coercivity of the exchange-coupled nanocomposites could be tuned from 0.7 to 2.8 kOe and the saturation magnetization could be controlled from 93 to 160 emu g(-1). This work provides a bottom-up approach using exchange-coupled nanocomposites for engineering advanced permanent magnets with controllable magnetic properties. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Evolution of Fe Species during the Synthesis of Over-Exchanged Fe/ZSM5 Obtained by Chemical Vapor Deposition of FeCl3

    NARCIS (Netherlands)

    Koningsberger, D.C.; Battiston, A.A.; Bitter, J.H.; Groot, F.M.F. de; Overweg, A.R.; Stephan, O.; Bokhoven, J.A. van; Kooyman, P.J.

    2003-01-01

    The evolution of iron in over-exchanged Fe/ZSM5 prepared via chemical vapor deposition of FeCl{3} was studied at each stage of the synthesis. Different characterization techniques (EXAFS, HR-XANES, }5{}7{Fe Mossbauer spectroscopy, }2{}7{Al NMR, EELS, HR-TEM, XRD, N{2} physisorption, and FTIR

  18. Evolution of Fe species during the synthesis of over-exchanged Fe/ZSM5 obtained by chemical vapor deposition of FeCl3

    NARCIS (Netherlands)

    Battiston, AA; Bitter, JH|info:eu-repo/dai/nl/160581435; de Groot, FMF|info:eu-repo/dai/nl/08747610X; Overweg, AR; Stephan, O; van Bokhoven, JA; Kooyman, PJ; van der Spek, C; Vanko, G; Koningsberger, DC

    2003-01-01

    The evolution of iron in over-exchanged Fe/ZSM5 prepared via chemical vapor deposition of FeCl3 was studied at each stage of the synthesis. Different characterization techniques (EXAFS, HR-XANES, Fe-57 Mossbauer spectroscopy, Al-27 NMR, EELS, HR-TEM, XRD, N-2 physisorption, and FTIR spectroscopy)

  19. Inulin affects iron dialyzability from FeSO4 and FeEDTA solutions but does not alter Fe uptake by Caco-2 cells

    Science.gov (United States)

    The in vitro effects of inulin on the fluxes of Fe (FFe), uptake by Caco-2 cells from FeSO4 and FeEDTA which are commonly used for food fortification, were evaluated. For an element to be absorbed it is necessary that it should be soluble in the gastrointestinal tract, thus, changes in FFe diffussio...

  20. Epidemiologia dos acidentes no surfe no Brasil

    Directory of Open Access Journals (Sweden)

    J. Steinman

    2000-02-01

    Full Text Available Apesar do grande número de praticantes do surfe no Brasil, nenhum trabalho científico nacional foi dedicado à caracterização e análise epidemiológica das lesões esportivas desse grupo. Pretendeu-se com este estudo identificar os tipos e lesões mais freqüentes relacionadas à prática do surfe recreacional e competitivo no Brasil. Estudaram-se suas causas, a parte do corpo atingida, sua gravidade, relacionadas às diferentes condições de surfe. Foram distribuídos 21.300 questionários pelos Estados litorâneos do Nordeste, Sudeste e Sul do Brasil. Um banco de dados foi montado com respostas de 930 praticantes, que relataram 927 lesões que necessitaram atenção médica ou que impediram a prática do surfe por um ou mais dias (num período de três anos. A população incluiu 67,5% surfistas recreacionais, 29,4% amadores e 3,1% profissionais, a maior parte do sexo masculino (95,3%; 56,6% praticam o esporte há mais de cinco anos. A média de idade foi de 23,7 anos (DP = 6,30. A maioria das lesões foi de natureza traumática (82,5% e ocorreu durante a prática do surfe recreacional (96,2%. As lesões mais comuns foram as lacerações (44%, as contusões (16,9% e as lesões musculoligamentares (15,5%; 38% das lesões atingiram os membros inferiores, 17,9% os membros superiores e 15,6% a cabeça. O tempo de afastamento da prática do surfe devido à lesão foi: 54,2% até 7 dias, 20,7% entre 7 e 14 dias, 10,1% entre 14 e 30 dias e 14,8% mais de 30 dias. Nesta amostra, a incidência de lesões foi de 2,47 para cada mil dias de surfe. Esta incidência foi inferior à obtida em outros estudos. Apesar da alta incidência de lesões traumáticas neste estudo, a alta prevalência de dores lombares recorrentes (28,4%, dores no pescoço (27,3%, dores nos ombros (20,5% e dores nos joelhos (12,5% sugere que as lesões de esforço repetido sejam um problema comum entre os surfistas.

  1. In situ study on the formation of FeTe

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude; Wulff, Anders Christian; Yue, Zhao

    2011-01-01

    The formation of the FeTe compound from a mixture of Fe and Te powders was studied in situ by means of high-energy synchrotron X-ray diffraction. FeTe does not form directly from the starting elements; instead, FeTe2 forms as an intermediate product. During a 2 °C/min heating ramp, Te first reacts...... between 200 and 350 °C with a part of the Fe powder to form FeTe2, which then further reacts between 350 and 530 °C with the remaining Fe to yield FeTe. This phase formation path is simpler than in the case of FeSe and the differences are discussed in terms of the equilibrium phase diagrams of these two...

  2. Formation mechanisms of neutral Fe layers in the thermosphere at Antarctica studied with a thermosphere-ionosphere Fe/Fe+ (TIFe) model

    Science.gov (United States)

    Chu, Xinzhao; Yu, Zhibin

    2017-06-01

    With a thermosphere-ionosphere Fe/Fe+ (TIFe) model developed from first principles at the University of Colorado, we present the first quantitative investigation of formation mechanisms of thermospheric Fe layers observed by lidar in Antarctica. These recently discovered neutral metal layers in the thermosphere between 100 and 200 km provide unique tracers for studies of fundamental processes in the space-atmosphere interaction region. The TIFe model formulates and expands the TIFe theory originally proposed by Chu et al. that the thermospheric Fe layers are produced through the neutralization of converged Fe+ layers. Through testing mechanisms and reproducing the 28 May 2011 event at McMurdo, we conceive the lifecycle of meteoric metals via deposition, transport, chemistry, and wave dynamics for thermospheric Fe layers with gravity wave signatures. While the meteor injection of iron species is negligible above 120 km, the polar electric field transports metallic ions Fe+ upward from their main deposition region into the E-F regions, providing the major source of Fe+ (and accordingly Fe) in the thermosphere. Atmospheric wave-induced vertical shears of vertical and horizontal winds converge Fe+ to form dense Fe+ layers. Direct electron-Fe+ recombination is the major channel to neutralize Fe+ layers to form Fe above 120 km. Fe layer shapes are determined by multiple factors of neutral winds, electric field, and aurora activity. Gravity-wave-induced vertical wind plays a key role in forming gravity-wave-shaped Fe layers. Aurora particle precipitation enhances Fe+ neutralization by increasing electron density while accelerating Fe loss via charge transfer with enhanced NO+ and O2+ densities.type="synopsis">type="main">Plain Language SummaryThe discoveries of neutral metal layers reaching near 200 km in the thermosphere have significant scientific merit because such discoveries challenge the current understandings of upper atmospheric composition, chemistry, dynamics

  3. Determination of Fe Deficiency Tolerance in Sunflower Genotypes

    Directory of Open Access Journals (Sweden)

    Ayfer Alkan Torun

    2017-10-01

    Full Text Available Iron deficiency (Fe is an important nutritional disorder of plants and humans worldwide including Turkey. Sunflower is known as a Fe sensitive crop and its deficiency leads to severe yield and quality losses. In this study, the sensitivity of different sunflower genotypes to Fe deficiency was determined. For this purpose, sunflower genotypes TR-6149-SA, TR-3080 and 6480 were grown either without Fe (0 µmol or with Fe (100 µmol hydroponically. At the end of experiment symptom grade, SPAD value, chlorophyll concentration, shoot dry matter yield, Fe-reductase activity, shoot Fe concentration and pH value of growth medium were measured. It was found out that Fe uptake and Fe reductase activity were the most important factors determining the Fe-deficiency tolerance of a genotype. In the deficiency of Fe conditions, the activity of Fe reductase enzyme in the roots was found higher in the genotype of TR-3080 compared to the other genotypes. The results revealed that the genotypic responses to the different Fe concentrations applied are significantly different and Fe reductase enzyme activity may play an important role in amelioration of iron deficiency.

  4. Festim Barroco: Um estudo sobre o significado cultural da festa de Nossa Senhora dos Prazeres dos Montes Guararapes em Pernambuco

    OpenAIRE

    CÔRREA, Alexandre Fernandes

    1993-01-01

    A festa de Nossa Senhora dos Prazeres e da Pitomba acontece há três séculos, no alto dos Montes Guararapes em Pernambuco. Esta cerimônia religiosa e popular aglutina um numero impressionante de pessoas todos os anos. A partir de um estudo etnológico sobre o significado cultural destas festividades, podemos perceber a sua importância social e compreender a força que estes tipos rituais tem na nossa sociedade. Eles expressam o modo particular de organizarmos nosso mundo social através dos mitos...

  5. Sobriedade e embriaguez: a luta dos soldados de Cristo contra as festas dos tupinambás

    Directory of Open Access Journals (Sweden)

    João Azevedo Fernandes

    2007-01-01

    Full Text Available O artigo analisa a luta dos missionários cristãos, em especial os jesuítas, contra as festas e as bebidas alcoólicas dos tupinambás. Eles perceberam que, nestas festas, a cultura tupinambá, principal obstáculo à evangelização, se renovava e se reafirmava constantemente. O artigo também explora as principais estratégias usadas pelos europeus para alcançar o objetivo de extinguir as festas dos índios.

  6. Dos and Don'ts for a Fabulous Pedicure

    Science.gov (United States)

    Dos & Don’ts for a Fabulous Pedicure Everyone needs a little foot pampering from time to time! Whether you are getting ... pedicure at home or in the salon: Don’t shave your legs before receiving a pedicure. Resist ...

  7. Tecnologia dos sonhos em Artemidoro, Freud, Jung e nos Warlpiri

    Directory of Open Access Journals (Sweden)

    Abrahão de Oliveira Santos

    2014-08-01

    Full Text Available Apresentaremos distintas tecnologias dos sonhos: em Artemidoro, Freud, Jung e nos Warlpiri. Artemidoro revela a mensagem onírica imprescindível à condução do cidadão, com os elementos das instituições, da cidade, do cosmo. Com Freud, no moderno mundo europeu, o sonho recebe o sentido da interioridade. Outra leitura é de Carl Jung. O uso dos sonhos tem seu sentido histórico, se relacionando com as práticas de governo, os modos de condução da vida e da cidade. Para além das tradições eurodescendentes e mentalistas vigentes, apresentaremos a tecnologia coletiva dos sonhos dos Warlpiri e uma nova possibilidade de lidarmos com a experiência onírica.

  8. Molecular magnetism of a linear Fe(III)-Mn(II)-Fe(III) complex. Influence of long-range exchange interaction

    Science.gov (United States)

    Lengen, M.; Bill, E.; Butzlaff, C.; Trautwein, A. X.; Winter, M.; Chaudhuri, P.

    1994-12-01

    The magnetic properties of [L-Fe(III)-dmg3Mn(II)-Fe(III)-L] (ClO4)2 have been characterized by magnetic susceptibility, EPR, and Mössbauer studies. L represents 1,4,7-trimethyl-, 1,4,7-triazacyclononane and dmg represents dimethylglyoxime. X-ray diffraction measurements yield that the arrangement of the three metal centers is strictly linear with atomic distances d Fe-Mn=0.35 nm and d Fe-Fe=0.7 nm. Magnetic susceptibility measurements (3 295 K) were analyzed in the framework of the spin-Hamiltonian formalism considering Heisenberg exchange and Zeeman interaction: Ĥ= J Fe-Mn( S Fe1+ S Fe2) S Mn + J Fe-Fe( S Fe1 S Fe2) +gΜB S total B. The spins S Fe1= S Fe2 = S Mn=5/2 of the complex are antiferromagnetically coupled, yielding a total spin of S total=5/2 with exchange coupling constants F Fe-Mn=13.4 cm-1 and J Fe-Fe= 4.5 cm-1. Magnetically split Mössbauer spectra were recorded at 1.5 K under various applied fields (20 m T, 170 mT, 4T). The spin-Hamiltonian analysis of these spectra yields isotropic magnetic hyperfine coupling with A total/( g N Μ N)=-18.5 T. The corresponding local component A Fe is related to A total via spin-projection: A total=(6/7)AFe. The resulting A Fe/( g NΜN)=-21.6 T is in agreement with standard values of ferric high-spin complexes. Spin-Hamiltonian parameters as obtained from Mössbauer studies and exchange coupling constants as derived from susceptibility measurements are corroborated by temperature-dependent EPR studies.

  9. Interesses e dificuldades dos pais na alfabetização dos filhos

    Directory of Open Access Journals (Sweden)

    Eliane Porto Di Nucci

    Full Text Available participação na alfabetização de seus filhos foi o principal objetivo deste estudo. Foram sujeitos desta pesquisa 25 mães de crianças em pré-escola e 1ª série de uma escola particular. Foi utilizado um questionário com duas perguntas sobre os interesses e as dificuldades dos sujeitos e sobre a disponibilidade de tempo neste contexto. Os resultados mostraram que os sujeitos parecem estar dispostos a participar mais efetivamente desse processo em casa e em parceria com a escola. Os interesses parecem estar voltados à evolução da escrita na criança e aos métodos de alfabetização. As dificuldades apareceram em relação às condutas diante da aprendizagem da criança.

  10. DOS-elimination by aerosol separator equipment. Abscheidung von DOS in Aerosolabscheidern

    Energy Technology Data Exchange (ETDEWEB)

    Stiess, M.; Schwalme, J. (Georg-Simon-Ohm-Fachhochschule, Nuernberg (Germany). Fachbereich Verfahrenstechnik); Ziemer, W. (Zander Klimatechnik GmbH, Nuernberg (Germany))

    1992-04-01

    Lubrication oil mist collectors in manufacturing plants contain for example wave-plate or wire mesh demisters as preseparators and pleated fiber-filter plates with a PTFE-coating at one side for final air cleaning. These three separator types are tested. The aerosol is DOS (dioctylsebacate). The test-plant is large enough to incorporate commercially available separator elements, so that influences of the construction can be considered. Fractional and total filter efficiencies as well as pressure drop, dependent on gas velocity and aerosol concentration are measured. The wave-plate separator is unsuitable and the wire mesh demister is suited for preseparation. The fiber-filter-plates show better pressure drop and separation results, if the PTFE-layer lies on the inner (clean) filter-surface than on the outer surface. Experimental results are compared with theoretical computations. (orig.).

  11. RbCuFe(PO42

    Directory of Open Access Journals (Sweden)

    Mongi Ben Amara

    2013-08-01

    Full Text Available A new iron phosphate, rubidium copper(II iron(III bis(phosphate, RbCuFe(PO42, has been synthesized as single crystals by the flux method. This compound is isostructural with KCuFe(PO42 [Badri et al. (2011, J. Solid State Chem. 184, 937–944]. Its structure is built up from Cu2O8 units of edge-sharing CuO5 polyhedra, interconnected by FeO6 octahedra through common corners to form undulating chains that extend infinitely along the [011] and [01-1] directions. The linkage of such chains is ensured by the PO4 tetraedra and the resulting three-dimensional framework forms quasi-elliptic tunnels parallel to the [101] direction in which the Rb+ cations are located.

  12. Magnetostatic Interaction in Fe-Co Nanowires

    Directory of Open Access Journals (Sweden)

    Laura Elbaile

    2012-01-01

    Full Text Available Arrays of Fe-Co alloy nanowires with diameter around 35 nm and several micrometers in length have been synthesized by codepositing Fe and Co into porous anodic alumina. The morphology, structure, and magnetic properties of the nanowires (hysteresis loops and remanence curves were characterized by SEM, TEM, X-ray diffraction (XRD, and VSM, respectively. The XRD patterns indicate that the Fe-Co nanowires present a body-centered cubic (bcc structure and a preferred (110 orientation perpendicular to the template surface. From the hysteresis loops obtained with the magnetic field applied in the axis direction of the nanowires, we can observe that the coercive field slightly decreases when the nanowire length increases. This magnetic behaviour is analyzed considering the shape anisotropy and the dipolar interactions among nanowires.

  13. Dos madres adolescentes, dos vínculos: ¿qué marca la diferencia?

    Directory of Open Access Journals (Sweden)

    Pierina Traverso K.

    2007-06-01

    Full Text Available Se presenta un estudio de caso de dos madres adolescentes de la misma edad (17 años, con el cual se intenta explorar las representaciones maternas y las interacciones madre-bebe, es decir, las distintas maneras de “estar con” el bebe. El estudio pretende discutir que la maternidad adolescente en sí misma no es un factor de riesgo, sino que otras variables moderadoras como la calidad de las redes de sostenimiento y la función reflexiva con que cada joven madre cuenta. Las representaciones maternas fueron evaluadas a través de una entrevista semi-estructurada sobre representaciones maternas (Traverso, 2006 y las interacciones madre-bebe fueron medidas y filmadas a través del Mother-Infant Global-Ratings para dos y cuatro meses (Murray, Fiori-Cowley & Cooper, 1996.---A case study of two adolescent mothers of the same age is presented (17 years old with which it is intended to explore the maternal representations and mother-baby interactions, that is, the different ways of “being with” a baby. The study pretends to discuss that it is not adolescent motherhood in itself a risk factor, but other mediating variables such as supportnetwork and the reflective function with which each young mother counts. Maternal representations were assessed through a semi-structured interview about maternal representations (Traverso, 2006 and the mother-infant interactions were measured and filmed through the Mother-Infant Global Ratings for two and four months (Murray, Fiori-Cowley & Cooper, 1996.

  14. MOBILE MARKETING: A NOVA ABORDAGEM DOS MARKETEERS E DOS NOVOS TURISTAS

    Directory of Open Access Journals (Sweden)

    Marco Paula Pinto

    2014-12-01

    Full Text Available O Mobile Marketing é uma das áreas do marketing digital que apresenta mais potencialidades para as empresas, em geral e em particular para as da área do turismo. Permite a criação de um canal direto com o cliente, que lhe permite adquirir um estilo de vida mais versátil uma vez que lhe facilita a aquisição de produtos únicos graças à possibilidade de personalização, conetividade e mobilidade em qualquer lugar e a qualquer hora. O presente estudo tem como objetivo a sensibilização da importância do marketing digital para as empresas, principalmente das relacionadas com a atividade turística, o qual apresenta as características e identifica as potencialidades das funcionalidades associadas, bem como a evolução dos dipositivos móveis até ao impacto que as tecnologias mobile poderão causar nas empresas e na sociedade atual. No presente artigo, concluiu-se que a tecnologia está cada vez mais presente na sociedade e concede vantagens competitivas às empresas em termos de versatilidade, personalização e divulgação dos seus produtos através de um canal direto e em tempo real com o cliente, através de um dispositivo móvel que cada vez mais é considerado um acessório necessário para os consumidores.

  15. Lugar e veneração dos santos hoje

    Directory of Open Access Journals (Sweden)

    Zilles, Urbano

    2007-01-01

    Full Text Available A veneração dos santos, na América Latina, extrapola as fronteiras do catolicismo. Na igreja distancia o catolicismo da hierarquia do catolicismo do povo. O autor justifica, dentro de limites, a veneração dos santos, a partir de intercomunicação e do amor, sem desviar-se do cristocentrismo de fé cristã

  16. Sífilis secundaria en cavidad oral: Reporte de dos casos Oral secondary syphilis: Two cases report

    Directory of Open Access Journals (Sweden)

    M G Díaz

    2008-12-01

    Full Text Available La sífilis es una enfermedad infecciosa humana causada por una bacteria: el Treponema pallidum. La enfermedad es transmitida por contacto directo a través de lesiones durante el estadio primario y secundario, por vía transplacentaria intrauterina o a través del canal uterino; puede afectar cualquier órgano de la economía causando un número infinito de presentaciones clínicas. La sífilis secundaria cursa con manifestaciones mucocutáneas características y eventual sintomatología general. La presentación clínica de nuestros dos pacientes es singular ya que solo poseían lesiones en la cavidad oral. La respuesta al tratamiento instaurado fue buena.Syphilis is a human infectious disease caused by the bacterium Treponema pallidum. The disease is transmitted by direct contact with a lesion during the primary or secondary stages, in utero by the transplacental route, or during delivery as the baby passes through an infected canal. The bacterium may infect any organ, causing an infinite number of clinical presentations. Secondary syphilis is characterized by mucocutaneous lesions, a flulike syndrome, and generalized adenopathy. Hepatosplenomegaly may be present. The oral mucosa is the second most frequent site of luetic lesions; the genital areas are the most frequent. In the oral cavity, the most characteristic lesion is a whitish mucosal patch, normally located on the lips, tongue, or palate, which is extremely contagious. The differential diagnosis of this lesion may include oral squamous carcinoma, leukoplakia, candidosis, lichen planus, and hairy oral leukoplakia. Definitive diagnosis is based on clinical information and completed by laboratory examinations even the biopsy can help us. With the diagnosis of secondary syphilis treatment with penicillin G benzathine must be started. We present two cases of secondary syphilis with oral lesions only; the first one, a man with macule covered with a whitish membrane on palate mucosa and a

  17. Estudio de inmunogenicidad para dos vacunas recombinantes contra hepatitis B

    Directory of Open Access Journals (Sweden)

    O. Juliao

    1991-12-01

    Full Text Available Este estudio compara la inmunogenicidad (seroconversión, seroprotección e Hiperrespuesta, producida por dos vacunas recombinantes contra la hepatitis B (Engerix-B de Bélgica y Cubana, en dos esquemas (012 y 016 meses, empleando los métodos de cuantificación para Anti-HBsAg (Abbott y Organón, los cuales fueron también comparados. En el estudio participaron 257 voluntarios,  divididos al azar en 4 grupos (dos vacunas, dos esquemas. Resultados: los dos métodos de Abbon y Organon, no presentan diferencias estadísticas significativas. La vacuna cubana muestra una mayor respuesta inmunogénica para dos dosis de vacuna y para el esquema 012. No hay diferencia entre los esquemas 012 y 016 y en el esquema 016 no se ven diferencias estadísticamente significativas con la vacuna Engerix-B. En esta Última el esquema 016 muestra mejores resultados que el 012.

  18. Electrodeposition of Fe powder from acid electrolytes

    Directory of Open Access Journals (Sweden)

    VESNA M. MAKSIMOVIC

    2008-08-01

    Full Text Available Polarization characteristics of the electrodeposition processes of Fe powders from sulfate and chloride electrolytes and the morphology of the obtained powders were investigated. The morphology depended on the anion presence in the electrolyte but not on the current density in the investigated range. A characteristic feature of the dendritic powder with cauliflower endings obtained from sulfate electrolyte is the presence of cone-like cavities and the crystallite morphology of the powders surface. On the other hand, Fe powders electrodeposited from chloride electrolyte appear in the form of agglomerates. A soap solution treatment applied as a method of washing and drying provides good protection from oxidation of the powders.

  19. Superconductivity in FeH5

    Science.gov (United States)

    Majumdar, Arnab; Tse, John S.; Wu, Min; Yao, Yansun

    2017-11-01

    The recently synthesized FeH5 at high pressure is calculated to be a superconductor with a critical temperature (Tc) of 51 K at 130 GPa. The crystal structure of this compound can be described as stacking bilayers of a puckered hexagonal honeycomb of H atoms sandwiched between slabs of atomic Fe and H atoms. The honeycomb layers resemble the predicted structure of a metallic and high Tc Cmca phase of solid hydrogen. Electron-phonon interactions were mainly derived from coupling of the electronic bands with bending vibrations of the hydrogens in the puckered layers.

  20. Diseño de dos metodologías moleculares para la rápida identificación de aislamientos de Staphylococcus aureus resistente a meticilina asociados a la comunidad en Colombia

    Directory of Open Access Journals (Sweden)

    Javier Antonio Escobar

    2012-06-01

    Full Text Available Introducción. Los aislamientos de Staphylococcus aureus resistente a la meticilina asociado a la comunidad (SARM-AC, están aumentando la frecuencia de infecciones en personas sanas de la comunidad y en pacientes hospitalizados. En Colombia y en la región andina estos aislamientos tienen un componente genético relacionado con el clon pandémico USA300. Objetivo. Diseñar y estandarizar dos metodologías para la diferenciación rápida de aislamientos colombianos de S. aureus resistente a la meticilina asociado a la comunidad de los asociados al hospital (SARM-AH. Materiales y métodos. Se estandarizaron dos metodologías moleculares para la identificación de aislamientos de S. aureus resistente a la meticilina asociado a la comunidad. La primera se basa en la digestión diferencial con tres enzimas de restricción de los genes cinasa de carbamato (arcC y cinasa de guanilato (gmk para los tipos de secuencia 5 (ST5 y 8 (ST8, correspondientes a aislamientos de S. aureus resistente a la meticilina asociado al hospital y asociado a la comunidad, respectivamente. La segunda se basa en la amplificación por reacción en cadena de la polimerasa de cinco factores de virulencia que se encuentran de manera diferencial en estos aislamientos. Las dos metodologías fueron validadas en 237 aislamientos clínicos de S. aureus resistente a la meticilina. Resultados. Con la primera metodología se identificaron el 100 % y 93,2 % de los aislamientos de S. aureus resistente a la meticilina asociado a la comunidad y asociado al hospital, respectivamente. Con la segunda metodología se identificaron correctamente los dos tipos de aislamientos. Conclusiones. Estas dos metodologías son una buena alternativa en términos de ahorro en tiempo y dinero comparadas con otras técnicas, como la electroforesis en campo pulsado y la tipificación de secuencias multilocus para la rápida identificación de aislamientos de S. aureus resistente a la meticilina asociado a la

  1. Evidence for weak electronic correlations in Fe-pnictides

    Energy Technology Data Exchange (ETDEWEB)

    Yang, W.L.

    2010-04-29

    Using x-ray absorption and resonant inelastic x-ray scattering, charge dynamics at and near the Fe L edges is investigated in Fe pnictide materials, and contrasted to that measured in other Fe compounds. It is shown that the XAS and RIXS spectra for 122 and 1111 Fe pnictides are each qualitatively similar to Fe metal. Cluster diagonalization, multiplet, and density-functional calculations show that Coulomb correlations are much smaller than in the cuprates, highlighting the role of Fe metallicity and strong covalency in these materials. Best agreement with experiment is obtained using Hubbard parameters U {approx}< 2eV and J {approx} 0.8eV.

  2. Evidence for weak electronic correlations in Fe-Pnictides

    Energy Technology Data Exchange (ETDEWEB)

    Yang, W. L.; Sorini, A. P.; Chen, C-C.; Moritz, B.; Lee, W.-S.; Vernay, F.; Olalde-Velasco, P.; Denlinger, J. D.; Delley, B.; Chu, J.-H.; Analytis, J.G.; Fisher, I. R.; Ren, Z. A.; Yang, J.; Lu, W.; Zhao, Z. X.; van den Brink, J.; Hussain, Z.; Shen, Z.-X.; Devereaux, T. P.

    2009-06-11

    Using x-ray absorption and resonant inelastic x-ray scattering, charge dynamics at and near the Fe L edges is investigated in Fe pnictide materials, and contrasted tothat measured in other Fe compounds. It is shown that the XAS and RIXS spectra for 122 and 1111 Fe pnictides are each qualitatively similar to Fe metal. Cluster diagonalization, multiplet, and density-functional calculations show that Coulomb correlations are much smaller than in the cuprates, highlighting the role of Fe metallicity and strong covalency in these materials. Best agreement with experiment is obtained using Hubbard parameters U<~;; 2eV and J ~;; 0.8eV.

  3. Thermodynamic assessment of the La-Fe-O system

    DEFF Research Database (Denmark)

    Povoden-Karadeniz, E.; Grundy, A.N.; Chen, Ming

    2009-01-01

    The La-Fe and the La-Fe-O systems are assessed using the Calphad approach, and the Gibbs energy functions of ternary oxides are presented. Oxygen and mutual La and Fe solubilities in body-centered cubic (bcc) and face-centered cubic (fcc) structured metallic phases are considered in the modeling......-sublattice model for ionic liquids. The calculated La-Fe phase diagram, LaO1.5-FeO x phase diagrams at different oxygen partial pressures, and phase equilibria of the La-Fe-O system at 873, 1073, and 1273 K as a function of oxygen partial pressures are presented....

  4. Catalytic Methane Decomposition over Fe-Al2O3

    KAUST Repository

    Zhou, Lu

    2016-05-09

    The presence of a Fe-FeAl2O4 structure over an Fe-Al2O3 catalysts is demonstrated to be vital for the catalytic methane decomposition (CMD) activity. After H2 reduction at 750°C, Fe-Al2O3 prepared by means of a fusion method, containing 86.5wt% FeAl2O4 and 13.5wt% Fe0, showed a stable CMD activity at 750°C for as long as 10h. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Shape anisotropy and hybridization enhanced magnetization in nanowires of Fe/MgO/Fe encapsulated in carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Aryee, Dennis; Seifu, Dereje

    2017-05-01

    Arrays of tunneling magnetoresistance (TMR) nanowires were synthesized for the first time by filling Fe/MgO/Fe inside vertically grown and substrate supported carbon nanotubes. The magnetic properties of nanowires and planar nanoscale thin films of Fe/MgO/Fe showed several similarities, such as two-fold magnetic symmetry and ratio of orbital moment to spin moment. Nanowires of Fe/MgO/Fe showed higher saturation magnetization by a factor of 2.7 compared to planar thin films of Fe/MgO/Fe at 1.5 kOe. The enhanced magnetic properties likely resulted from shape anisotropy of the nanowires and as well as the hybridization that occur between the π- electronic states of carbon and 3d-bands of the Fe-surface.

  6. The thermal properties of amorphous Fe40Pd40B20 and Fe60Pd20B20 thin films

    Science.gov (United States)

    Chen, Yuan-Tsung

    2015-07-01

    The thermal stability of FePdB thin films was studied using nonisothermal and isothermal analyses. X-ray diffraction (XRD) patterns indicated that Fe40Pd40B20 and Fe60Pd20B20 films with thicknesses in the range 25-75 Å were amorphous, whereas Fe40Pd40B20 and Fe60Pd20B20 films with thicknesses in the range 100-200 Å exhibited a nanocrystalline FePd (111) structure. The crucial glass forming ability index (γ and γm) was determined using the differential scanning calorimetry (DSC) results of amorphous FePdB films. The Kissinger formula was applied to calculate the activation energy (Q) of crystallization for determining the resistance of the films to crystallization. Thermal analysis showed that the thermal stability and incubation time of Fe40Pd40B20 are more favorable than those of Fe60Pd20B20.

  7. Physicochemical and Photocatalytic Properties of Fe-Pillared Bentonite at Various Fe Content

    Directory of Open Access Journals (Sweden)

    Is Fatimah

    2016-10-01

    Full Text Available Iron-pillared bentonites (Fe/Bents were successfully prepared using a ferric chloride precursor. The prepared samples were characterized using XRD, BET and SEM-EDX. The results show that the pillared bentonite physicochemical character is affected by the iron content in a precursor solution. By Fe content variation it is found that Fe content in Fe/Bents is not linearly correlated with the specific surface area and the increased in d001 in which both the maximum specific surface are and d001 reach maximum at the Fe content of 20 mmol/g. Due to the kinetics of photocatalytic activity in phenol removal, it is concluded that in photo-Fenton-like processes. Copyright © 2016 BCREC GROUP. All rights reserved Received: 29th March 2016; Revised: 30th August 2016; Accepted: 1st September 2016 How to Cite: Fatimah, I., Nurkholifah, Y.Y. (2016. Physicochemical and Photocatalytic Properties of Fe-Pillared Bentonite at Various Fe Content. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (3: 398-405 (doi:10.9767/bcrec.11.3.456.398-405 Permalink/DOI: http://doi.org/10.9767/bcrec.11.3.456.398-405

  8. First principles calculations of interlayer exchange coupling in bcc Fe/Cu/Fe structures

    Energy Technology Data Exchange (ETDEWEB)

    Kowalewski, M.; Heninrich, B. [Simon Fraser Univ., Burnaby, British Columbia (Canada); Schulthess, T.C.; Butler, W.H. [Oak Ridge National Lab., TN (United States)

    1998-01-01

    The authors report on theoretical calculations of interlayer exchange coupling between two Fe layers separated by a modified Cu spacer. These calculations were motivated by experimental investigations of similar structures by the SFU group. The multilayer structures of interest have the general form: Fe/Cu(k)/Fe and Fe/Cu(m)/X(1)/Cu(n)/Fe where X indicates one AL (atomic layer) of foreign atoms X (Cr, Ag, or Fe) and k, m, n represent the number of atomic layers of Cu. The purpose of the experimental and theoretical work was to determine the effect of modifying the pure Cu spacer by replacing the central Cu atomic layer with the atomic layer of foreign atoms X. The first principles calculation were performed using the Layer Korringa-Kohn-Rostoker (LKKR) method. The theoretical thickness dependence of the exchange coupling between two semi-infinite Fe layers was calculated for pure Cu spacer thicknesses in the range of 0 < k < 16. The effect of the foreign atoms X on the exchange coupling was investigated using the structure with 9 AL Cu spacer as a reference sample. The calculated changes in the exchange coupling are in qualitative agreement with experiment.

  9. Solid FeS lubricant: a possible alternative to MoS2 for Cu-Fe-based friction materials

    Science.gov (United States)

    Peng, Tao; Yan, Qing-zhi; Zhan, Xiao-lu; Shi, Xiao-jiao

    2017-11-01

    Molybdenum disulfide (MoS2) is one of the most commonly used solid lubricants for Cu-Fe-based friction materials. Nevertheless, MoS2 reacts with metal matrices to produce metal sulfides (e.g., FeS) and Mo during sintering, and the lubricity of the composite may be related to the generation of FeS. Herein, the use of FeS as an alternative to MoS2 for producing Cu-Fe-based friction materials was investigated. According to the reaction principle of thermodynamics, two composites—one with MoS2 (Fe-Cu-MoS2 sample) and the other with FeS (FeS-Cu2S-Cu-Fe-Mo sample), were prepared and their friction behaviors and mechanical properties were compared. The results showed that MoS2 reacted with the Cu-Fe matrix to produce FeS, metallic ternary sulfides, and Mo when sintered at 1050°C. The MoS2-Cu-Fe and FeS-Cu2S-Cu-Fe-Mo samples thereby exhibited similar characteristics with respect to phase composition, density, hardness, and tribological behaviors. Micrographs of the worn surfaces revealed that the stable friction regime for both composites stemmed from the iron sulfides friction layers rather than from the molybdenum sulfides layers.

  10. Comparación bromatológica, microbiológica y sensorial de dos formulaciones de salchichas elaboradas con carne de conejo (Oryctolagus cuniculus

    Directory of Open Access Journals (Sweden)

    José Igor Hleap Zapata

    2014-01-01

    Full Text Available En este estudio se evaluaron dos formulaciones diferentes de salchichas elaboradas con carne de conejo, utilizando como extendedores harina de chontaduro (Bactris gasipaes y almidón modificado de maíz. Ambas formulaciones consistieron en 60% de carne de conejo, 12% de grasa de cerdo y 4% del respectivo extensor, el porcentaje restante correspondió a hielo y condimentos. Los análisis bromatológicos mostraron los contenidos siguientes (base seca: (1 en carne = 60.90% de proteína, 33.65% de grasa, 4.46% de cenizas y 0.99% de carbohidratos; (2 en salchichas elaboradas con adición de harina de chontaduro = 15.96% de proteína, 13.55% de grasa, 4.10% de cenizas, 3.42% de carbohidratos y 60.63% de humedad; y (3 en salchichas elaboradas con adición de almidón modificado de maíz = 14.54% de proteína, 11.53% de grasa, 3.81% de cenizas, 3.99% de carbohidratos y 63.42% de humedad. Las pruebas microbiológicas consistieron en el análisis de los parámetros tradicionales de calidad y seguridad, además de mediciones sensoriales utilizando pruebas afectivas de preferencia, de grado de satisfacción y de aceptación que permitieron concluir que las salchichas elaboradas presentaron características de inocuidad para el ser humano y de gran aceptación gracias a sus buenas propiedades organolépticas, resultando productos tipo Premium según la NTC 1325.

  11. Prevalencia de defectos congénitos diagnosticados en el momento del nacimiento en dos hospitales de diferente nivel de complejidad, Cali, Colombia, 2012-2013

    Directory of Open Access Journals (Sweden)

    Harry Pachajoa

    2015-06-01

    Full Text Available Introducción. Los defectos congénitos son alteraciones morfológicas que pueden ser diagnosticadas antes, durante o después del nacimiento. Se han implementado diversos sistemas de vigilancia en hospitales de referencia, principalmente en aquellos de alta complejidad. Objetivo. Comparar la prevalencia de los defectos congénitos en dos hospitales de diferente nivel de complejidad de la ciudad de Cali. Materiales y métodos. Se llevó a cabo un estudio descriptivo basado en la metodología del Estudio Colaborativo Latinoamericano de Malformaciones Congénitas, durante 20 meses en un hospital de mediana complejidad y en otro de alta complejidad. Resultados. Durante el periodo de estudio se atendieron 7.140 nacimientos, en 225 de los cuales se presentó al menos un defecto congénito, con una prevalencia del 1,7 % (IC95% 1,3-2,0 en el hospital de mediana complejidad y de 7,4 % (IC95% 6,2-8,7 en el de alta complejidad. En el primero, las frecuencias más altas correspondieron a polidactilia (15 %, apéndice preauricular (8 % y pie equino varo (7 %, mientras que en el segundo, correspondieron a comunicación interventricular (10 %, hidronefrosis congénita (7 % y defectos de la pared abdominal (6 %. Conclusiones. La prevalencia de los defectos congénitos varió de un hospital a otro, dependiendo de su nivel de complejidad, y del tipo y la seriedad de los defectos. La vigilancia epidemiológica en los diferentes niveles de atención es una herramienta útil para estimar acertadamente la prevalencia en la ciudad, además de constituir una buena base para la planificación y orientación de los recursos.

  12. The effects of interfacial exchange coupling in Fe/ErFeO3 heterostructures

    Science.gov (United States)

    Tang, J.; Ke, Y. J.; He, W.; Zhang, X. Q.; Zhang, Y. S.; Zhang, W.; Li, Y.; Ahmad, S. S.; Cheng, Z. H.

    2017-05-01

    Exploring exchange bias in ferromagnetic (FM)/antiferromagnetic (AFM) heterostructures is vital for both fundamental magnetism and practical application. However, in the case of conventional FM/AFM systems, the essential field cooling process above the Néel temperature of AFM materials hinders their application if the Néel temperature is far higher than room-temperature. Here, we report the effects of interfacial exchange coupling in Fe/ErFeO3 heterostructures. The magnetic-field-induced switchable exchange bias, originating from the AFM exchange coupling between Fe film and Dzyaloshinskii-Moriya-interaction-induced net moment of ErFeO3 along c axis, is successfully achieved without field cooling or in-field growth process of AFM. Different from the most previous pinning layer using a hard FM or traditional AFM, ErFeO3 pinning layer has the advantages of both the magnetic field sensitivity (~780 Oe) and ultrahigh dynamic frequency. In addition, although Fe film is polycrystalline, it exhibits a strong uniaxial magnetic anisotropy resulted from the so-called ‘spin-flop-coupling effect’, i.e. the magnetic coupling between Fe film and the compensated G-type AFM spins of EFO along a axis. Interestingly, the exchange bias field and asymmetric switching field offer entirely different information about the asymmetry of magnetization reversal near hard axis. The asymmetric switching field is further proved to be an effective measure to determine the weak unidirectional magnetic anisotropy for film with nearly 180° domain wall displacement. Our experimental results provide a practical method to establish room-temperature exchange bias in FM/G-type AFM without field cooling. Furthermore, the magnetic-field-induced switchable exchange-bias, the spin-flop coupling effect and the angular dependent asymmetry of magnetization reversal in the vicinity of hard axis in Fe/ErFeO3 heterostructures may provide new insights on the interfacial exchange coupling in FM/AFM systems.

  13. Crystallization behavior and magnetic properties in High Fe content FeBCSiCu alloy system

    Energy Technology Data Exchange (ETDEWEB)

    Fan, X.D., E-mail: fanxd@seu.edu.cn; Shen, B.L., E-mail: blshen@seu.edu.cn

    2015-07-01

    High Fe content FeBCSiCu nanocrystalline alloys are prepared by annealing melt-spun amorphous ribbons with aim at increasing saturation magnetic flux density. Microstructures identified by XRD and TEM reveal that Cu addition inhibits the surface crystallization of Fe{sub 86}B{sub 7}C{sub 7} alloy and improve its glass-forming ability. Activation energy of crystallization calculated by Kissinger's equation indicates that both Cu and Si addition promotes the precipitation of α-Fe phase and improves the thermal stability. VSM and DC B–H loop tracer measurements show that the Fe{sub 85.5}B{sub 7}C{sub 6}Si{sub 1}Cu{sub 0.5} nanocrystalline alloy exhibits high saturation magnetic flux density of 1.8 T and low coercivity of 10 A/m, respectively. AC properties measured by AC B–H analyzer show this alloy exhibits low core loss of 0.35 W/kg at 1 T at 50 Hz. Low material cost and convenient productivity make the Fe{sub 85.5}B{sub 7}C{sub 6}Si{sub 1}Cu{sub 0.5} nanocrystalline alloy an economical application in industry. - Highlights: • Cu addition inhibits the surface crystallization and improves the GFA. • The competitive formation of Fe{sub 3}C and α-Fe phase impedes the devitrification. • Fe{sub 85.5}B{sub 7}C{sub 6}Si{sub 1}Cu{sub 0.5} nanocrystalline alloy exhibits excellent magnetic properties. • The alloy system has an economical advantage and convenient productivity.

  14. Microminerais para bovinos de corte nas pastagens nativas dos Campos de Cima da Serra, RS, Brasil

    Directory of Open Access Journals (Sweden)

    Wunsch Carolina

    2005-01-01

    Full Text Available Em face das poucas informações disponíveis sobre a composição mineral das pastagens nativas da região dos Campos de Cima da Serra (RS, o presente trabalho de pesquisa objetivou avaliar os teores dos principais microminerais, em diferentes épocas do ano, e relacionar o perfil mineral destas pastagens com as necessidades nutricionais recomendadas pelo NRC (1996 para bovinos de corte. O projeto foi conduzido em vinte propriedades particulares, em Cambará do Sul, utilizando áreas de campo nativo que estavam sendo normalmente utilizadas em pastoreio por bovinos de corte e/ou ovinos, e que não tinham sofrido nenhum tipo de melhoria, reforma ou recuperação (exceto queimada, no mínimo nos últimos 20 anos. Colheram-se nas diversas estações, durante um ano, e dentro de uma mesma área predeterminada em cada propriedade, amostras para determinar as concentrações de ferro, manganês, cobre e zinco. Verificou-se efeito do mês de coleta sobre todos os minerais analisados. Constataram-se teores suficientes de Mn e Fe para todas as categorias de bovinos de corte analisadas. Entretanto, algumas amostras apresentaram níveis tóxicos aos animais. Os teores de Cu não são suficientes para todas as categorias de bovinos em alguns meses do ano. Os teores de Zn estiveram abaixo das exigências mínimas para bovinos de corte.

  15. SCF- Xα-SW MO Study of Fe-O and Fe-OH chemical bonds; applications to the mössbauer spectra and magnetochemistry of hydroxyl-bearing Fe3+ oxides and silicates

    Science.gov (United States)

    Sherman, David M.

    1985-10-01

    Results of SCF- Xα-SW molecular orbital calculations on (FeO4(OH)2)7- and (FeO6)9- clusters are used to investigate the differences between Fe-O and Fe-OH bonding in hydroxyl-bearing iron oxides and silicates. The Fe3+-OH- bond is more ionic, and has a smaller spinpolarization, then the Fe3+-O2- bond. The smaller spinpolarizability of OH- ligands explains why superexchange interactions between hydroxo-bridged Fe3+ cations are much weaker than those between oxo-bridged Fe3+ cations. Replacement of oxygens in the Fe3+ coordination environment by OH- ligands appears to promote the covalency between Fe3+ centers and O2- oxygens. The increased covalency lowers the effective spin of the Fe atom. This, in turn, explains the decreased magnetic hyperfine fields at the Fe nucleus in FeOOH polymorphs relative to those found in Fe3+ oxides.

  16. Exchange-coupled Fe3O4/CoFe2O4 nanoparticles for advanced magnetic hyperthermia

    Science.gov (United States)

    Glassell, M.; Robles, J.; Das, R.; Phan, M. H.; Srikanth, H.

    Iron oxide nanoparticles especially Fe3O4, γ-Fe2O3 have been extensively studied for magnetic hyperthermia because of their tunable magnetic properties and stable suspension in superparamagnetic regime. However, their relatively low heating capacity hindered practical application. Recently, a large improvement in heating efficiency has been reported in exchange-coupled nanoparticles with exchange coupling between soft and hard magnetic phases. Here, we systematically studied the effect of core and shell size on the heating efficiency of the Fe3O4/CoFe2O4 core/shell nanoparticles. The nanoparticles were synthesized using thermal decomposition of organometallic precursors. Transmission electron microscopy (TEM) showed formation of spherical shaped Fe3O4 and Fe3O-/CoFe2O4 nanoparticles. Magnetic measurements showed high magnetization (≅70 emu/g) and superparamagnetic behavior for the nanoparticles at room temperature. Magnetic hyperthermia results showed a large increase in specific absorption rate (SAR) for 8nm Fe3O4/CoFe2O4 compared to Fe3O4 nanoparticles of the same size. The heating efficiency of the Fe3O4/CoFe2O4 with 1 nm CoFe2O4 (shell) increased from 207 to 220 W/g (for 800 Oe) with increase in core size from 6 to 8 nm. The heating efficiency of the Fe3O4/CoFe2O4 with 2 nm CoFe2O4 (shell) and core size of 8 nm increased from 220 to 460 W/g (for 800 Oe). These exchange-coupled Fe3O4/CoFe2O4 core/shell nanoparticles can be a good candidate for advanced hyperthermia application.

  17. Fast defluorination and removal of norfloxacin by alginate/Fe@Fe3O4 core/shell structured nanoparticles.

    Science.gov (United States)

    Niu, Hongyun; Dizhang; Meng, Zhaofu; Cai, Yaqi

    2012-08-15

    Alginate-Fe(2+)/Fe(3+) polymer coated Fe(3)O(4) magnetic nanoparticles (Fe(3)O(4)@ALG/Fe MNPs) with core/shell structure are prepared and used as heterogeneous Fenton nanocatalyst to degrade norfloxacin (NOF). The Fenton-like process based on Fe(3)O(4)@ALG/Fe shows much higher efficiency on NOF degradation. Compared with Fe(3)O(4) nanoparticle-H(2)O(2) system, NOF degradation in Fe(3)O(4)@AlG/Fe-H(2)O(2) system can be conducted in a wide pH range (pH 3.5-6.5) and independent on temperature. With 0.98 mM H(2)O(2) and 0.4 g L(-1) Fe(3)O(4)@ALG/Fe, 100% of NOF and 90% of TOC is removed within 60 min, and the fluorine element in NOF molecule changes into F(-) ions within 1 min, indicating that NOF degradation in this Fenton-like reaction is performed through direct defluorination pathway. XPS analysis shows that TOC removal in reaction solution mainly results from the adsorption of NOF degradation intermediates on catalyst. Due to the paramagneticity and high saturation magnetization of Fe(3)O(4)@ALG/Fe, the used catalyst with adsorbed NOF intermediate is collected from aqueous solution by applying an external magnetic field, leading to complete removal of NOF from water samples. As being composed of inorganic materials and biopolymer, Fe(3)O(4)@ALG/Fe MNPs are robust, thermo-stable, nontoxic and environmentally friendly. These attractive features endow Fe(3)O(4)@ALG/Fe as a potent Fenton-like catalyst for fluoroquinolones degradation. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Regulation of brain copper homeostasis by the brain barrier systems: Effects of Fe-overload and Fe-deficiency

    Energy Technology Data Exchange (ETDEWEB)

    Monnot, Andrew D.; Behl, Mamta; Ho, Sanna; Zheng, Wei, E-mail: wzheng@purdue.edu

    2011-11-15

    Maintaining brain Cu homeostasis is vital for normal brain function. The role of systemic Fe deficiency (FeD) or overload (FeO) due to metabolic diseases or environmental insults in Cu homeostasis in the cerebrospinal fluid (CSF) and brain tissues remains unknown. This study was designed to investigate how blood-brain barrier (BBB) and blood-SCF barrier (BCB) regulated Cu transport and how FeO or FeD altered brain Cu homeostasis. Rats received an Fe-enriched or Fe-depleted diet for 4 weeks. FeD and FeO treatment resulted in a significant increase (+ 55%) and decrease (- 56%) in CSF Cu levels (p < 0.05), respectively; however, neither treatment had any effect on CSF Fe levels. The FeD, but not FeO, led to significant increases in Cu levels in brain parenchyma and the choroid plexus. In situ brain perfusion studies demonstrated that the rate of Cu transport into the brain parenchyma was significantly faster in FeD rats (+ 92%) and significantly slower (- 53%) in FeO rats than in controls. In vitro two chamber Transwell transepithelial transport studies using primary choroidal epithelial cells revealed a predominant efflux of Cu from the CSF to blood compartment by the BCB. Further ventriculo-cisternal perfusion studies showed that Cu clearance by the choroid plexus in FeD animals was significantly greater than control (p < 0.05). Taken together, our results demonstrate that both the BBB and BCB contribute to maintain a stable Cu homeostasis in the brain and CSF. Cu appears to enter the brain primarily via the BBB and is subsequently removed from the CSF by the BCB. FeD has a more profound effect on brain Cu levels than FeO. FeD increases Cu transport at the brain barriers and prompts Cu overload in the CNS. The BCB plays a key role in removing the excess Cu from the CSF.

  19. Ferromagnetic resonance on oxideless magnetic Fe and FeRh nanoparticles; Ferromagnetische Resonanz an oxidfreien magnetischen Fe und FeRh Nanopartikeln

    Energy Technology Data Exchange (ETDEWEB)

    Trunova, Anastasia

    2009-05-25

    This work is dedicated to investigations of structural and magnetic properties of the colloidal Fe/Fe{sub x}O{sub y} nanocubes (13 nm) and the Fe{sub x}Rh{sub 100-x} core/shell nanoparticles (2 nm). As compared with other works, where the measurements on oxidized nanoparticles were carried out, we additionally performed investigations on nanoparticles in an oxide free state. In order to make the measurements on oxide free particles possible, oxygen- and hydrogenplasma was used to remove the ligands and reduce the oxide shell of the Fe nanocubes. The oxide free Fe nanocubes were covered with a Ag/Pt protective coating to prevent them from new oxidation. This method allowed carrying out the magnetic measurements on oxide free Fe nanocubes. Micromagnetic simulations as well as simulations of the high frequency susceptibility were used for the data analysing. It was found that both the g-factor g=2.09{+-}0.01 and the anisotropy constant K{sub 4}=(4.8{+-}0.5).10{sup 4} J/m{sup 3} coincide with that of bulk iron. However, the saturation magnetization M{sub S}(5 K)=(1.2{+-}0.12).10{sup 6} A/m differs from the bulk value by 30%. The reduction by 30% compared to the bulk value in the case of nanoparticles may be caused by the following possible reasons: a) the presence of inner oxide layer (approx. 10 at.%) that cannot be reduced; b) the anti-parallel order between magnetic moments of iron core and magnetic moments of antiferomagnetic iron oxide; c) some structural changes of the surface after plasma treatment. The obtained damping parameter {alpha}=0.03{+-}0.005 is ten times larger than that of the Fe layers as it is known for nanoparticles systems in general. The core/shell Fe{sub x}Rh{sub 100-x} nanoparticles (x=80,50) were produced under Ar-atmosphere and were sealed into a quartz tube to prevent oxidation. The analysis of g-factors shows that the value for the FePh nanoparticles with Fe-rich core is larger (g=2.08{+-}0.01) than that for the nanoparticles with Rh

  20. Melting in the Fe-Ni system

    Science.gov (United States)

    Lord, O. T.; Walter, M. J.; Vocadlo, L.; Wood, I. G.; Dobson, D. P.

    2012-12-01

    The melting temperature of the Fe-rich core alloy at the inner core boundary (ICB) condition of 330 GPa is a key geophysical parameter because it represents an anchor point on the geotherm. An accurate knowledge of the melting curves of candidate alloys is therefore highly desirable. In spite of this, there is still considerable uncertainty in the melting point even of pure Fe at these conditions; estimates range from as low as 4850K based on one laser heated diamond anvil cell (LHDAC) study [1] to as high as 6900K based on recent quantum Monte Carlo calculations [2]. In reality we expect that the bulk core alloy may contain 5-10 wt% Ni (based on cosmochemical and meteoritic arguments) and up to 10 wt% of an as yet undetermined mix of light elements (with Si, S, C and O being the most likely candidates). While some recent studies have looked at the effects of light elements on the melting curve of Fe [e.g.: 3,4] with some of these studies including a small amount of Ni in their starting material, to date there has been no systematic study of melting temperatures in the Fe-Ni system. To address this issue, we have embarked upon just such a study. Using the LHDAC we have determined the melting curve of the pure Ni end-member to 180 GPa, and that of pure Fe to 50 GPa, using perturbations in the power vs. temperature function as the melting criterion [5]. Ar or NaCl were employed as pressure media while temperature was measured using standard spectroradiometric techniques [6]. In the case of Ni, perturbations were observed for both the sample and the Ar medium, allowing us to determine the melting curve of Ar and Ni simultaneously. Our results thus far for Ni and Ar agree closely with all of the available data, while extending the melting curves by a factor of two in pressure. In the case of Fe, our current dataset is also in good agreement with previous studies [2,7]. The agreement of all three melting curves with the literature data as well as other materials

  1. "En este libro no hallo cosa que se oponga a los dogmas de nuestra Santa Fe ni a las buenas costumbres": um estudo sobre dedicatórias, prólogos e censuras em tratados de cirurgia e de medicina do Setecentos

    Directory of Open Access Journals (Sweden)

    Eliane Cristina Deckmann Fleck

    2013-04-01

    Full Text Available Neste artigo, analisamos os textos das dedicatórias, censuras, aprovações e prólogos publicados em tratados de cirurgia e de medicina, escritos ou editados na Espanha durante a primeira metade do século XVIII, e que tiveram comprovada circulação, constituindo-se em obras de referência para jesuítas que atuaram como boticários e médicos na América. Para além da identificação das estratégias de escrita evidenciadas nestes textos, que precedem o conteúdo propriamente dito desses tratados impressos, avaliamos como, através deles, seus autores e editores procuraram apontar caminhos adequados de leitura e, assim, difundir determinados conhecimentos científicos na Espanha e nas áreas de seu vasto império colonial no século XVIII.

  2. Insights into Resistance to Fe Deficiency Stress from a Comparative Study of In Vitro-Selected Novel Fe-Efficient and Fe-Inefficient Potato Plants.

    Science.gov (United States)

    Boamponsem, Georgina A; Leung, David W M; Lister, Carolyn

    2017-01-01

    Iron (Fe) deficiency induces chlorosis (IDC) in plants and can result in reduced plant productivity. Therefore, development of Fe-efficient plants is of great interest. To gain a better understanding of the physiology of Fe-efficient plants, putative novel plant variants were regenerated from potato (Solanum tubersosum L. var. 'Iwa') callus cultures selected under Fe deficient or low Fe supply (0-5 μM Fe). Based on visual chlorosis rating (VCR), 23% of callus-derived regenerants were classified as Fe-efficient (EF) and 77% as Fe-inefficient (IFN) plant lines when they were grown under Fe deficiency conditions. Stem height was found to be highly correlated with internodal distance, leaf and root lengths in the EF plant lines grown under Fe deficiency conditions. In addition, compared to the IFN plant lines and control parental biotype, the EF plants including the lines named A1, B2, and B9, exhibited enhanced formation of lateral roots and root hairs as well as increased expression of ferritin (fer3) in the leaf and iron-regulated transporter (irt1) in the root. These morphological adaptations and changes in expression the fer3 and irt1 genes of the selected EF potato lines suggest that they are associated with resistance to low Fe supply stress.

  3. Insights into Resistance to Fe Deficiency Stress from a Comparative Study of In Vitro-Selected Novel Fe-Efficient and Fe-Inefficient Potato Plants

    Directory of Open Access Journals (Sweden)

    Georgina A. Boamponsem

    2017-09-01

    Full Text Available Iron (Fe deficiency induces chlorosis (IDC in plants and can result in reduced plant productivity. Therefore, development of Fe-efficient plants is of great interest. To gain a better understanding of the physiology of Fe-efficient plants, putative novel plant variants were regenerated from potato (Solanum tubersosum L. var. ‘Iwa’ callus cultures selected under Fe deficient or low Fe supply (0–5 μM Fe. Based on visual chlorosis rating (VCR, 23% of callus-derived regenerants were classified as Fe-efficient (EF and 77% as Fe-inefficient (IFN plant lines when they were grown under Fe deficiency conditions. Stem height was found to be highly correlated with internodal distance, leaf and root lengths in the EF plant lines grown under Fe deficiency conditions. In addition, compared to the IFN plant lines and control parental biotype, the EF plants including the lines named A1, B2, and B9, exhibited enhanced formation of lateral roots and root hairs as well as increased expression of ferritin (fer3 in the leaf and iron-regulated transporter (irt1 in the root. These morphological adaptations and changes in expression the fer3 and irt1 genes of the selected EF potato lines suggest that they are associated with resistance to low Fe supply stress.

  4. Direct Evidence of Fe2+-Fe3+ Charge Ordering in the Ferrimagnetic Hematite-Ilmenite Fe1.35Ti0.65O3-δ Thin Films

    Science.gov (United States)

    Bocher, L.; Popova, E.; Nolan, M.; Gloter, A.; Chikoidze, E.; March, K.; Warot-Fonrose, B.; Berini, B.; Stéphan, O.; Keller, N.; Dumont, Y.

    2013-10-01

    In this Letter we highlight direct experimental evidence of Fe2+-Fe3+ charge ordering at room temperature in hematite-ilmenite Fe1.35Ti0.65O3-δ epitaxial thin films grown by pulsed laser deposition, using aberration-corrected scanning transmission electron microscopy coupled to high-resolution energy electron-loss spectroscopy. These advanced spectromicroscopy techniques demonstrate a strong modulation of the Fe2+ valence state along the c axis. Density functional theory calculations provide crucial information on the key role of oxygen vacancies in the observed charge distributions. Their presence at significant levels leads to the localization of extra electrons onto reduced Fe2+ sites, while Ti remains solely +4. The magnetic and transport properties of these films are reviewed in the light of the present results regarding their ferrimagnetic character correlated with the Fe2+ modulation and their semiconducting behavior interpreted by an Efros-Shklovskii variable-range hopping conduction regime via Fe2+ and Fe3+ centers. The experimental evidence of only one type of mixed valence state, i.e., Fe2+ and Fe3+, in the Fe2-xTixO3-δ system will thus help to interpret further the origin of its geomagnetic properties and to illuminate fundamental issues regarding its spintronic potential.

  5. Fe as hydrogen/halogen bond acceptor in square pyramidal Fe(CO)5.

    Science.gov (United States)

    Aiswaryalakshmi, P; Mani, Devendra; Arunan, E

    2013-08-05

    Hydrogen bonded complexes formed between the square pyramidal Fe(CO)5 with HX (X = F, Cl, Br), showing X-H···Fe interactions, have been investigated theoretically using density functional theory (DFT) including dispersion correction. Geometry, interaction energy, and large red shift of about 400 cm(-1) in the HX stretching frequency confirm X-H···Fe hydrogen bond formation. In the (CO)5Fe···HBr complex, following the significant red-shift, the HBr stretching mode is coupled with the carbonyl stretching modes. This clearly affects the correlation between frequency shift and binding energy, which is a hallmark of hydrogen bonds. Atoms in Molecule (AIM) theoretical analyses show the presence of a bond critical point between the iron and the hydrogen of HX and significant mutual penetration. These X-H···Fe hydrogen bonds follow most but not all of the eight criteria proposed by Koch and Popelier (J. Phys. Chem. 1995, 99, 9747) based on their investigations on C-H···O hydrogen bonds. Natural bond orbital (NBO) analysis indicates charge transfer from the organometallic system to the hydrogen bond donor. However, there is no correlation between the extent of charge transfer and interaction energy, contrary to what is proposed in the recent IUPAC recommendation (Pure Appl. Chem. 2011, 83, 1637). The "hydrogen bond radius" for iron has been determined to be 1.60 ± 0.02 Å, and not surprisingly it is between the covalent (1.27 Å) and van der Waals (2.0) radii of Fe. DFT and AIM theoretical studies reveal that Fe in square pyramidal Fe(CO)5 can also form halogen bond with ClF and ClH as "halogen bond donor". Both these complexes show mutual penetration as well, though the Fe---Cl distance is closer to the sum of van der Waals radii of Fe and Cl in (CO)5Fe···ClH, and it is about 1 Å less in (CO)5Fe···ClF.

  6. One-pot synthesis of urchin-like FePd-Fe3O4 and their conversion into exchange-coupled L1(0)-FePd-Fe nanocomposite magnets.

    Science.gov (United States)

    Yu, Yongsheng; Sun, Kewei; Tian, Yuan; Li, X-Z; Kramer, M J; Sellmyer, D J; Shield, J E; Sun, Shouheng

    2013-10-09

    We report a one-pot synthesis of urchin-like FePd-Fe3O4 nanocomposites, spherical clusters of FePd nanoparticles (NPs) with spikes of Fe3O4 nanorods (NRs), via controlled thermal decomposition of Fe(CO)5 and reduction of Pd(acac)2. The FePd NPs with sizes between 6 and 9 nm self-aggregate into 60 nm superparticles (SPs), and Fe3O4 NRs grow on the surface of these SPs. Reductive annealing at 500 °C converts the FePd-Fe3O4 into exchange-coupled nanocomposites L1(0)-FePd-Fe with their Hc tunable from 0.8 to 2.6 kOe and Ms controlled from 90 to 190 emu/g. The work provides a general approach to L1(0)-FePd-Fe nanocomposite magnets for understanding exchange coupling at the nanoscale. The concept may be extended to other magnetic nanocomposite systems and may help to build superstrong magnets for magnetic applications.

  7. In Situ Derived NixFe1-xOOH/NiFe/NixFe1-xOOH Nanotube Arrays from NiFe Alloys as Efficient Electrocatalysts for Oxygen Evolution.

    Science.gov (United States)

    Wang, An-Liang; Dong, Yu-Tao; Li, Mei; Liang, Chaolun; Li, Gao-Ren

    2017-10-11

    Herein, Ni x Fe 1-x OOH/NiFe/Ni x Fe 1-x OOH sandwich-structured nanotube arrays (SNTAs) supported on carbon fiber cloth (CFC) (Ni x Fe 1-x OOH/NiFe/Ni x Fe 1-x OOH SNTAs-CFC) have been developed as flexible high-performance oxygen evolution reaction (OER) catalysts by a facile in situ electrochemical oxidation of NiFe metallic alloy nanotube arrays during oxygen evolution process. Benefiting from the advantages of high conductivity, hollow nanotube array, and porous structure, Ni x Fe 1-x OOH/NiFe/Ni x Fe 1-x OOH SNTAs-CFC exhibited a low overpotential of ∼220 mV at the current density of 10 mA cm -2 and a small Tafel slope of 57 mV dec -1 in alkaline solution, both of which are smaller than those of most OER electrocatalysts. Furthermore, Ni x Fe 1-x OOH/NiFe/Ni x Fe 1-x OOH SNTAs-CFC exhibits excellent stability at 100 mA cm -2 for more than 30 h. It is believed that the present work can provide a valuable route for the design and synthesis of inexpensive and efficient OER electrocatalysts.

  8. Magnetic properties of Sm-Fe-N bulk magnets produced from Cu-plated Sm-Fe-N powder

    Directory of Open Access Journals (Sweden)

    Tetsuji Saito

    2017-05-01

    Full Text Available In this study, Cu-plated Sm-Fe-N powder was prepared for consolidation by the SPS method. The structures and magnetic properties of Sm-Fe-N bulk magnets produced from the Cu-plated Sm-Fe-N powder were examined. It was found that the powder could be consolidated into bulk materials at low temperatures of 473–673 K. The Sm-Fe-N magnet produced at a temperature of 473K from the Cu-plated Sm-Fe-N powder showed a high coercivity of 9.5 kOe, close to that of the Sm-Fe-N powder.

  9. Mielencefalite espontânea dos camundongos

    Directory of Open Access Journals (Sweden)

    Hermínio Linhares

    1944-02-01

    Full Text Available 1 — Duas amostras de vírus capazes de produzir uma mielencefalite foram isoladas de dois camundongos brancos suíços, de criação, espontâneamente infetados, em um total de 7.000 animais examinados; uma terceira amostra foi obtida por trituração e filtração dos intestinos de camundongos aparentemente normais. 2 — Foram feitas separadamente dez passagens por inoculação intra¬cerebral em camundongos jovens e adultos. Verificou-se por testes de imunidade cruzada que as três amostras eram idênticas. Prossegiu-se então nas passagens com apenas uma das amostras. 3 — O poder infetante aumenta com o número de passagens: o período médio de incubação diminui e aumenta a letalidade. 4 — A infecção espontânea e experimental é descrita. A doença parece ser mais comum em animais jovens. O período de incubação varia de 5 a 30 dias. Às vêzes observa-se uma fase prodromica: fraqueza, menor atividade, dificuldade em andar; geralmente surge a paralisia flácida sem sintomas prévios, na grande maioria das vêzes, nos membros posteriores. Três formas clínicas foram observadas: super-aguda, aguda e crônica. 5 — Em camundongos normais o vírus pode ser demonstrado nas fezes e nos intestinos. Ele é comum no tubo digestivo e só ocasionalmente invade o sistema nervoso central, ou melhor, a encefalomielite e primàriamente uma doença do trato digestivo no qual a invasão do SNC é um acidente. 6 — O vírus passa através de velas de CHAMBERLAND L3 e L5, em BER KEFED V, N e W e em filtro Seitz EK, a suspensão sendo tão ativa como antes da filtração. Conserva-se bem em glicerina a 50% pelo menos 60 dias, se guardado na geladeira. Suspensão de cérebro e medula aquecida em banho-maria a 56°C por 30 minutos perde a atividade. 7 — O título variou entre 4.000 e 20.000 dmm. 8 — Obteve-se infecção por inoculação intracerebral, por instilação nasal e, com menos regularidade, por inoculação intraperitoneal; a via g

  10. Structural, magnetic, and electronic properties of high moment FeCo nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zehani, K., E-mail: zehani@icmpe.cnrs.fr [CMTR, ICMPE, UMR7182, CNRS – Université Paris Est Créteil, 2-8 rue Henri Dunant, F-94320 Thiais (France); Bez, R. [CMTR, ICMPE, UMR7182, CNRS – Université Paris Est Créteil, 2-8 rue Henri Dunant, F-94320 Thiais (France); LMOP, Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092 Tunis (Tunisia); Boutahar, A. [LPMMAT, Université Hassan II, Faculté des Sciences Ain Chock, B.P.5366 Maârif, Route d’El Jadida, km-8, Casablanca (Morocco); Hlil, E.K. [Institut Néel, CNRS et Université Joseph Fourier, BP 166, F-38042 Grenoble Cedex 9 (France); Lassri, H. [LPMMAT, Université Hassan II, Faculté des Sciences Ain Chock, B.P.5366 Maârif, Route d’El Jadida, km-8, Casablanca (Morocco); Moscovici, J. [CMTR, ICMPE, UMR7182, CNRS – Université Paris Est Créteil, 2-8 rue Henri Dunant, F-94320 Thiais (France); Mliki, N. [LMOP, Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092 Tunis (Tunisia); Bessais, L. [CMTR, ICMPE, UMR7182, CNRS – Université Paris Est Créteil, 2-8 rue Henri Dunant, F-94320 Thiais (France)

    2014-04-05

    Highlights: • The nanoparticles cobalt ferrite was synthesized in polyol medium (10 nm). • Subsequently, the ferrite is annealed under argon at 873 K for different times. • After annealing, we have obtained of nanoparticles FeCo. • Their Structural, electronic, and magnetic properties have been presented. • The sample annealed at 873 K for 4 h exhibits the best M{sub s} (M{sub s} = 235 emu g{sup −1}). -- Abstract: Soft-magnetic Fe{sub 55}Co{sub 45} alloy nanoparticles have been successfully synthesized by the polyol reduction process followed by annealing under argon. The diethylene glycol (DEG) was used as solvent and reducing agent simultaneously in this process. The synthesized samples of nanoparticles were annealed at 873 K for different times. The alloy formation processes, the evolution of the microstructure, the magnetic properties, and the DOS calculation have been investigated before and after samples annealing. The X-ray diffraction of the synthesized product before annealing shows that a cobalt ferrite is spinel structure of crystallite size of about 10 nm. X-ray diffraction analysis of the samples annealed at 873 K for different times also shows that of the FeCo alloy has been obtained by reducing the cobalt ferrite. It has been confirmed the formation of a body-centered-cubic (bcc) single phase structure where the wt.% increases with annealing times leading to a pure phase after annealing during 4 h. These results are confirmed by transmission electron microscopy study. The saturation magnetization of the Fe–Co alloys increases with annealing time, indicating an increasing homogeneity in composition and the single bcc FeCo phase formation. The highest saturation magnetization of 235 emu g{sup −1}with a low coercivity of 76 Oe was obtained for the Fe{sub 55}Co{sub 45}nanoparticles annealed during 4 h. The local random anisotropy constant K{sub L} has been extracted. This work presents also detailed information about total, and atom

  11. Characterization of Fe -doped silver phosphate glasses

    Indian Academy of Sciences (India)

    tures of the glass and at lower concentration of dopant, a nanostructure is obtained. Electrical conductivity mea- surements from 303 to 373 K in a frequency range from 100 Hz to 5 MHz have indicated that all glasses are ionic conductors with Ag+ ions as the charge carrier. Fe2O3 doping in silver phosphate glass increased ...

  12. Nanophase Fe 0 in lunar soils

    Indian Academy of Sciences (India)

    The agglutinitic glass is a quenched product of silicate melts, also produced by micrometeorite impacts on lunar soils. Reduction by solar wind hydrogen in agglutinitic melts may have produced immiscible droplets that solidified as globules. The exact mechanism of formation of such Fe0 globules in lunar soils remains ...

  13. Fe (III) complex of mefloquine hydrochloride: Synthesis ...

    African Journals Online (AJOL)

    As part of the ongoing research for more effective antimalarial drug, Fe (III) complex of mefloquine hydrochloride (antimalarial drug) was synthesized using template method. Mefloquine was tentatively found to have coordinated through the hydroxyl and the two nitrogen atoms in the quinoline and piperidine in the structure, ...

  14. Evaluación de la adherencia a la Guía de Buenas Prácticas Clínicas en la desviación del septo nasal Assessment of the adhesion to the Guide of Good Clinical Practices in deviation of the nasal septum

    Directory of Open Access Journals (Sweden)

    René Esteban Moreno Rajadel

    2006-12-01

    Full Text Available Se realizó un estudio descriptivo, retrospectivo, de serie de casos, con el objetivo de evaluar la adherencia a la Guía de Buenas Prácticas Clínicas en el tratamiento a los pacientes intervenidos quirúrgicamente a causa de una desviación del septo nasal. Se incluyeron los 373 pacientes operados en el servicio de otorrinolaringología del Hospital Universitario «Dr. Gustavo Aldereguía Lima» de Cienfuegos, en el período comprendido entre enero de 2002 y diciembre de 2005. En la evaluación de la adherencia a la guía, se tuvo en cuenta el porcentaje de las respuestas afirmativas y se consideraron, cualitativamente, cinco categorías: excelente (≥ 95 %, notable (90-94,9 %, adecuado (85-89,9 %, suficiente (80-84,9 % y deficiente (< 80 %. Predominaron los pacientes del sexo masculino en todos los grupos etáreos (241; 64,6 % y el grupo de 21-30 años de edad aportó el mayor número de casos (120; 32,2 %. No se reflejó el tipo de desviación del septo nasal en 20 (5,4 % de los expedientes clínicos revisados. La mayoría de los operados (316; 84,7 % presentaban desviaciones bajas. En la evaluación de la adherencia a la guías predominaron las preguntas evaluadas cualitativamente como notable (4; 50 %. La evaluación de la adherencia a la Guía de Buenas Prácticas Clínicas nos permitió evaluar el desempeño médico-quirúrgico en esta afección e identificar nuestras debilidades y fortalezas

  15. Protein immobilization onto electrochemically synthesized CoFe nanowires

    National Research Council Canada - National Science Library

    Torati, Sri Ramulu; Reddy, Venu; Yoon, Seok Soo; Kim, CheolGi

    2015-01-01

    CoFe nanowires have been synthesized by the electrodeposition technique into the pores of a polycarbonate membrane with a nominal pore diameter of 50 nm, and the composition of CoFe nanowires varying...

  16. Uranium and Iron XRF distribution and Fe speciation results

    Data.gov (United States)

    U.S. Environmental Protection Agency — Dataset 1: XRF image of U and Fe distribution Dataset 2: Fe linear combination fitting data. This dataset is associated with the following publication: Koster van...

  17. Magnetic and Moessbauer studies of Fe/V multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Fnidiki, A.; Juraszek, J.; Teillet, J. [Groupe de Metallurgie Physique, equipe Magnetisme et Applications, UMR CNRS 6634, Faculte des Sciences de Rouen, 76821 Mont-Saint-Aignan Cedex (France); Duc, N.H.; Danh, T.M. [Cryogenic Laboratory, University of Hanoi (Viet Nam); Kaabouchi, M.; Sella, C. [Laboratoire de Magnetisme et d' Optique, 92195 Meudon Bellevue (France)

    1998-07-06

    The structural and magnetic properties of rf-sputtered Fe/V multilayers with the elemental Fe and V layer thickness t{sub Fe}=t{sub V} and with the structural modulation period {lambda} ranging from 2 nm to 24 nm have been studied by high-angle x-ray diffraction, vibrating-sample magnetometry, and conversion-electron Moessbauer spectrometry methods at room temperature. The results show that the Fe/V interfaces are paramagnetic. The magnetic behaviour of the multilayers, hence, originates from the {alpha}-Fe at the centres of the individual subsystems and the iron-rich crystalline Fe(V) alloy lying near the interface. The spin orientation in the Fe layers is strongly aligned in the film plane. However, evidence for a weak perpendicular spin orientation associated with the magnetic topmost Fe layer is found. (author)

  18. Magnetic depth profiling of Fe/Au multilayer using neutron ...

    Indian Academy of Sciences (India)

    Au multilayer sample for characterizing the layer structure and magnetic moment density profile. Fe/Au multilayer shows strong spin-dependent scattering at interfaces, making it a prospective GMR material. Fe/Au multilayer with bilayer ...

  19. Exchange bias in sputtered FeNi/FeMn systems: Effect of short low-temperature heat treatments

    Energy Technology Data Exchange (ETDEWEB)

    Savin, Peter, E-mail: peter.savin@urfu.ru [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Guzmán, Jorge [Instituto de Ciencia de Materiales de Madrid-CSIC, 28049 Madrid (Spain); Lepalovskij, Vladimir [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Svalov, Andrey; Kurlyandskaya, Galina [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Departamento de Electricidad y Electrónica, Universidad del País Vasco (UPV/EHU), 48940 Leioa, Vizcaya (Spain); Asenjo, Agustina [Instituto de Ciencia de Materiales de Madrid-CSIC, 28049 Madrid (Spain); Vas’kovskiy, Vladimir [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Vazquez, Manuel [Department of Magnetism and Magnetic Nanomaterials, Laboratory of Magnetic Sensors, Ural Federal University, 620002 Ekaterinburg (Russian Federation); Instituto de Ciencia de Materiales de Madrid-CSIC, 28049 Madrid (Spain)

    2016-03-15

    Short (5 min) post-deposition thermal treatments under magnetic field at low temperature (up to 200 °C) performed in exchange-coupled FeNi(40 nm)/FeMn(20 nm) bilayer thin films prepared by magnetron sputtering are shown to be effective to significantly modify their exchange field (from around 40 Oe down to 27 Oe) between FeNi and FeMn layers. A similar exchange field decrease was observed for the first deposited FeNi layer of the FeNi(40 nm)/FeMn(20 nm)/FeNi(40 nm) trilayer films after the same thermal treatments. The exchange field value for the second FeNi layer was not substantially changed. The X-ray diffraction patterns indicates that such a heat treatment has no effect on the grain size and crystalline texture of the films, while atomic force microscope studies reveal an increase of the surface roughness after the treatment which is more noticeable in the case of the trilayer film. Analysis of the experimental results leads us to conclude that the variations of the exchange field after heat treatment are likely caused by a modification of interfacial roughness and/or interfacial magnetic structure, but unlikely by the changes in the microstructure and/or changes of composition of the antiferromagnetic FeMn layer. - Highlights: • FeNi/FeMn bilayers and FeNi/FeMn/FeNi trilayers were prepared by magnetron sputtering. • Post-deposition heat treatments at the temperatures below 200 °C during 5 min were made. • Annealing reduces the exchange field for the first FeNi layer in trilayers. • The exchange field value for the second FeNi layer was not substantially changed. • Exchange field changes are most likely caused by a modification of interface roughness.

  20. Fe3+-Doped TiO2 Nanotube Arrays on Ti-Fe Alloys for Enhanced Photoelectrocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Jiangdong Yu

    2016-06-01

    Full Text Available Highly ordered, vertically oriented Fe3+-doped TiO2 nanotube arrays (Fe-TNTs were prepared on Ti-Fe alloy substrates with different Fe contents by the electrochemical anodization method. The as-prepared Fe-TNTs were characterized by scanning electron microscope (SEM, transmission electron microscopy (TEM, X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS and related electrochemical techniques. XPS results demonstrated that Fe3+ ions were successfully doped into TiO2 nanotubes. The photoelectrochemical activity of Fe-TNTs was compared with that of pure TiO2 nanotube arrays (TNTs. The results showed that Fe-TNTs grown on low concentration (0.5 wt %–1 wt % Fe Ti-Fe alloys possessed higher photocurrent density than TNTs. The Fe-TNTs grown on Ti-Fe alloy containing 0.8 wt % Fe exhibited the highest photoelectrochemical activity and the photoelectrocatalytic degradation rate of methylene blue (MB aqueous solution was significantly higher than that of TNTs.

  1. Fe Sparing and Fe Recycling Contribute to Increased Superoxide Dismutase Capacity in Iron-Starved Chlamydomonas reinhardtii[W

    Science.gov (United States)

    Page, M. Dudley; Allen, Michael D.; Kropat, Janette; Urzica, Eugen I.; Karpowicz, Steven J.; Hsieh, Scott. I.; Loo, Joseph A.; Merchant, Sabeeha S.

    2012-01-01

    Fe deficiency is one of several abiotic stresses that impacts plant metabolism because of the loss of function of Fe-containing enzymes in chloroplasts and mitochondria, including cytochromes, FeS proteins, and Fe superoxide dismutase (FeSOD). Two pathways increase the capacity of the Chlamydomonas reinhardtii chloroplast to detoxify superoxide during Fe limitation stress. In one pathway, MSD3 is upregulated at the transcriptional level up to 103-fold in response to Fe limitation, leading to synthesis of a previously undiscovered plastid-specific MnSOD whose identity we validated immunochemically. In a second pathway, the plastid FeSOD is preferentially retained over other abundant Fe proteins, heme-containing cytochrome f, diiron magnesium protoporphyrin monomethyl ester cyclase, and Fe2S2-containing ferredoxin, demonstrating prioritized allocation of Fe within the chloroplast. Maintenance of FeSOD occurs, after an initial phase of degradation, by de novo resynthesis in the absence of extracellular Fe, suggesting the operation of salvage mechanisms for intracellular recycling and reallocation. PMID:22685165

  2. FCC Fe{sub 2}NiSi prepared by mechanical alloying and stabilization effect of L2{sub 1}B disorder on BCC Heusler structure

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Hongzhi, E-mail: luo_hongzhi@163.com [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China); Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Xin, Yuepeng; Ma, Yuexing; Liu, Bohua; Meng, Fanbin; Liu, Heyan [School of Materials Science and Engineering, Hebei University of Technology, Tianjin 300130 (China); Liu, Enke; Wu, Guangheng [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2016-12-01

    Fe{sub 2}NiSi FCC phase has been prepared by ball-milling successfully, which is different from the BCC Heusler phase prepared by arc-melting in previous literatures. The FCC Fe{sub 2}NiSi is a ferromagnet with a lattice constant of 3.58 Å. The phase stability of the FCC and BCC Fe{sub 2}NiSi has been compared by first-principles calculations. It has been found that the FCC structure has a lower total energy compared with the highly-ordered Heusler structures XA and L2{sub 1}, that is the reason why the FCC phase can be prepared by ball-milling. However, the Fe (A)–Ni (C) disorder in the BCC XA structure can lower its total energy further and make it smaller than the FCC phase. So the most stable structure in Fe{sub 2}NiSi is L2{sub 1}B, as has been observed in the arc-melting sample. This can be explained from their DOS structures. The calculated total moments for the FCC and BCC phases agree with their M{sub s} at 5 K quite well. - Highlights: • FCC Fe{sub 2}NiSi has been prepared by ball-milling successfully. • Phase stability of Fe{sub 2}NiSi with different structures has been investigated. • The BCC Heusler structure in Fe{sub 2}NiSi is stabilized by L2{sub 1}B disorder.

  3. Eficiência dos Ésteres de Fitoesteróis Alimentares na Redução dos Lípides Plasmáticos em Hipercolesterolêmicos Moderados

    Directory of Open Access Journals (Sweden)

    Lottenberg Ana M. P.

    2002-01-01

    Full Text Available OBJETIVO - Avaliar o efeito dos ésteres de fitoesteróis (FE da dieta, em função dos diferentes genótipos de apo E, sobre os lípides plasmáticos em indivíduos moderadamente hipercolesterolêmicos. MÉTODOS - Pacientes moderadamente hipercolesterolêmicos (20 a 60 anos de idade; 50 mulheres e 10 homens, mantidos em dieta habitual, receberam margarina (20g/dia enriquecida com fitoesteróis (2,8g/dia=1,68g de FE, ou margarina normal (placebo, por dois períodos de quatro semanas cada, em estudo duplo cego e cruzado. RESULTADOS - Fitoesteróis reduziram significativamente o colesterol total e o LDL-colesterol, respectivamente, em 10% e 12% quando comparado à fase basal de admissão ao programa, e 6% e 8% quando comparado à fase placebo. O HDL-colesterol e a trigliceridemia não se modificaram. CONCLUSÃO - Ésteres de fitoesteróis da dieta reduziram a colesterolemia e a redução do LDL-colesterol foi mais pronunciada nos indivíduos que apresentavam valores maiores de LDL-colesterol, quando admitidos no estudo. Em relação ao sinótipo de apo E não houve diferença significativa entre apo E 3/3 e apo E 3/4.

  4. Efficient spin injection and giant magnetoresistance in Fe / MoS 2 / Fe junctions

    KAUST Repository

    Dolui, Kapildeb

    2014-07-02

    We demonstrate giant magnetoresistance in Fe/MoS2/Fe junctions by means of ab initio transport calculations. We show that junctions incorporating either a monolayer or a bilayer of MoS2 are metallic and that Fe acts as an efficient spin injector into MoS2 with an efficiency of about 45%. This is the result of the strong coupling between the Fe and S atoms at the interface. For junctions of greater thickness, a maximum magnetoresistance of ∼300% is obtained, which remains robust with the applied bias as long as transport is in the tunneling limit. A general recipe for improving the magnetoresistance in spin valves incorporating layered transition metal dichalcogenides is proposed. © 2014 American Physical Society.

  5. Magnetic aftereffects in CoFeB/Ta/CoFeB spin valves of large area

    Science.gov (United States)

    Morgunov, R.; Lu, Y.; Lavanant, M.; Fache, T.; Deveaux, X.; Migot, S.; Koplak, O.; Talantsev, A.; Mangin, S.

    2017-08-01

    Magnetic aftereffect measurements on a synthetic antiferromagnet with strong perpendicular anisotropy are presented. Two types of magnetic transitions are observed in the CoFeB/Ta/CoFeB bilayer where the two ferromagnetic CoFeB layers are antiferromagnetically coupled: the transition from a parallel to an antiparallel CoFeB layers magnetization alignment and the transition between two possible antiparallel magnetization states. Magnetic relaxation measurements show a complete reversal in the case of the transition between the two antiferromagnetic configurations. The experimental data can be well fitted in the frame of extended exponential relaxation using the Fatuzzo-Labrune model. Consequently, the domain nucleation and domain-wall propagation can be studied as a function of temperature and applied field.

  6. Fe{sub 3}C/Fe nanoparticles with urea: Synthesis, structure and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaobai [College of Chemistry, Jilin University, Changchun, 130012 (China); School of Chemical and Pharmaceutical Engineering, Jilin Institute of Chemical Technology, Jilin, 132022 (China); Zhang, Daguang [Department of Orthopaedic Surgery, the First Hospital of Jilin University, Changchun, 130021 China (China); Ren, Xiaozhen; Gao, Jiajia [College of Chemistry, Jilin University, Changchun, 130012 (China); Han, Yu [Department of Chemistry, College of Science, Yanbian University, Yanji, 133002 China (China); Chen, Xiaodong [College of Chemistry, Jilin University, Changchun, 130012 (China); Shi, Zhan [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun, 130012 (China); Yang, Hua [College of Chemistry, Jilin University, Changchun, 130012 (China)

    2016-12-15

    Fe{sub 3}C/Fe nanocomposites were synthesized by a sol–gel method. Using urea as carbon source and reduce agent in the reaction process. The CTAB works as the surfactant and the bromine contained in CTAB plays a catalytic role. Appropriate choices of the amount of urea and CTAB, reaction temperature and time are very important to obtain high-quality of products. Above 650 °C, the precursor gel turned into the nanocomposites composed of iron carbide and iron. Their structures and magnetic properties are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). The possible formation mechanism of as-prepared nanostructures is discussed. - Highlights: • The Fe{sub 3}C/Fe composites were synthetized by sol–gel method. • Their structure, magnetic properties are researched by XRD, VSM and TEM. • The possible formation mechanisms of the composites is discussed.

  7. TEORES DE METAIS PESADOS E CARACTERIZAÇÃO MINERALÓGICA DOS SOLOS DO CEMITÉRIO MUNICIPAL DO BOQUEIRÃO, CURITIBA (PR

    Directory of Open Access Journals (Sweden)

    LARISSA KUMMER

    2013-11-01

    Full Text Available As características locais de um cemitério são importantes variáveis que determinam o caminho de contaminantes resultantes do processo de decomposição de cadáveres. Constituem-se também como fontes de contaminantes, o verniz, conservantes da madeira e as partes metálicas dos caixões, que podem liberar metais para o ambiente. O objetivo do trabalho foi estudar a mineralogia da fração argila e os teores de metais pesados dos solos do Cemitério Municipal do Boqueirão, em Curitiba (PR, e avaliar o risco de contaminação ambiental. Foram selecionados seis pontos dentro da área do cemitério, de onde se coletaram amostras em três profundidades (0-20, 20-80 e 80-120 cm. A fração de argila foi estudada por difratometria de raios X e análises térmicas. Os teores totais e trocáveis de Cr, Cu, Pb, Ni e Zn foram determinados. Os teores de Fe2O3 associados com minerais de Fe mais cristalinos foram baixos, o que reflete os baixos teores de Fe dos materiais de origem dos solos e diferentes estágios de desenvolvimentos dos solos. Dentre os metais analisados, os teores de Pb e Zn total foram os que apresentaram os maiores valores em relação a solos de mesmo material de origem, porém tais concentrações não são indicativas de poluição ambiental, e sim de uma branda contaminação. Conclui-se que os solos deste cemitério apresentam-se aptos para esta atividade, visto serem profundos, de textura argilosa e com alto potencial de adsorção de metais.

  8. Rapid thermal annealing of FePt and FePt/Cu thin films

    Energy Technology Data Exchange (ETDEWEB)

    Brombacher, Christoph

    2011-01-10

    Chemically ordered FePt is one of the most promising materials to reach the ultimate limitations in storage density of future magnetic recording devices due to its high uniaxial magnetocrystalline anisotropy and a corrosion resistance superior to rare-earth based magnets. In this study, FePt and FePt/Cu bilayers have been sputter deposited at room temperature onto thermally oxidized silicon wafers, glass substrates and self-assembled arrays of spherical SiO{sub 2} particles with diameters down to 10 nm. Millisecond flash lamp annealing, as well as conventional rapid thermal annealing was employed to induce the phase transformation from the chemically disordered A1 phase into the chemically ordered L1{sub 0} phase. The influence of the annealing temperature, annealing time and the film thickness on the ordering transformation and (001) texture evolution of FePt films with near equiatomic composition was studied. Whereas flash lamp annealed FePt films exhibit a polycrystalline morphology with high chemical L1{sub 0} order, rapid thermal annealing can lead to the formation of chemically ordered FePt films with (001) texture on amorphous SiO{sub 2}/Si substrates. The resultant high perpendicular magnetic anisotropy and large coercivities up to 40 kOe are demonstrated. Simultaneously to the ordering transformation, rapid thermal annealing to temperatures exceeding 600 C leads to a break up of the continuous FePt film into separated islands. This dewetting behavior was utilized to create regular arrays of FePt nanostructures on SiO{sub 2} particle templates with periods down to 50 nm. The addition of Cu improves the (001) texture formation and chemical ordering for annealing temperatures T{sub a} {<=}600 C. In addition, the magnetic anisotropy and the coercivity of the ternary FePtCu alloy can be effectively tailored by adjusting the Cu content. The prospects of FePtCu based exchange spring media, as well as the magnetic properties of FePtCu nanostructures fabricated

  9. Fe-catalyzed thermal conversion of sodium lignosulfonate to graphene

    Science.gov (United States)

    Sung Phil Mun; Zhiyong Cai; Jilei Zhang

    2013-01-01

    Sodium lignosulfonate (LS) from sulfite pulping processing was used as a carbon source to synthesize graphene. LS was mixed with Fe nanoparticles (FeNPs) as a catalyst and thermally treated at 1000 °C for 1 h. The Raman spectrum and X-ray diffraction pattern suggested that graphene sheets were formed in LS thermally treated with FeNPs (Fe-HTLS). Scanning...

  10. Removal of indigo blue using clinoptilolite-Fe; Remocion de azul indigo utilizando clinoptilolita-Fe

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez S, E. E.; Colin C, A. [Universidad Autonoma del Estado de Mexico, Facultad de Quimica, Paseo Tollocan esquina Paseo Colon s/n, Toluca 50180, Estado de Mexico (Mexico); Solache R, M. J. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico)], e-mail: edithgs77@yahoo.com.mx

    2008-07-01

    The removal of indigo blue from aqueous solutions was evaluated using modified clinoptilolite with Fe (Z-Fe) which was characterized by SEM, EDS analysis and specific area (BET). The process followed the kinetics of pseudo-second order and Langmuir isotherm. Sorption capacity obtained was 18 mg g{sup -1} and a solid-liquid ratio 10 g L{sup -1}. (Author)

  11. Electron Impact Excitation Collision Strengths for Extreme Ultraviolet Lines of Fe VII and Fe IX

    Science.gov (United States)

    Tayal, Swaraj S.; Zatsarinny, Oleg

    2014-08-01

    Extensive calculations are performed for electron excitation collision strengths and transitions probabilities for a wide range of ultraviolet lines in Fe VII and Fe IX. The collision strengths are calculated in the close-coupling approximation using the B-spline Breit-Pauli R-matrix method. The multiconfiguration Hartree-Fock method in conjunction with B-spline expansions is employed for an accurate representation of the target wave-functions. The close-coupling expansions include 189 and 370 fine-structure levels of Fe VII and Fe IX respectively. We have included levels of the 3p6, 3p53d,4l,5s, 3s3p63d,4s,4p, 3p43d2, 3s3p53d2 configurations and some low-lying levels of the 3p33d3 configuration for Fe IX. The effective collision strengths are obtained by averaging the electron collision strengths over a Maxwellian distribution of velocities at electron temperatures in the range from 104 to 107 K. There is a good agreement with the previous R-matrix calculation for transitions between first 17 levels of the 3p6, 3p53d, and 3s3p63d configurations in Fe IX. We were able to generate more accurate target states than those in the previous calculations. We included all 3p43d3nl correlation configurations and 3p-4f promotion for Fe VII which were found very important for accurate representation of 3dnl states. The present results considerably expand the existing data sets for Fe IX, allowing a more detailed treatment of the available measured spectra from different space observatories.This research work is supported by NASA grant NNX11AB62G from the Solar and Heliophysics program.

  12. Igualdade na diversidade: a luta pelo reconhecimento dos direitos dos homossexuais no Brasil

    Directory of Open Access Journals (Sweden)

    Osvaldo F. R. L. Fernandez

    2011-08-01

    Full Text Available Este artigo procura refletir sobre como a sistemática discriminação e violência contra os homossexuais, o que impede o próprio incremento da cidadania no Brasil, pois torna estruturalmente sancionada a exclusão e a desigualdade social. A principal questão é demonstrar que os preceitos constitucionais e os direitos fundamentais são violados quando são negados aos LGBT o direito à vida, à dignidade e à segurança. Assim, será defendida a tese de que a proteção e a promoção dos direitos desse segmento específico da sociedade significa também um ganho geral para o exercício da cidadania.

  13. O direito dos povos: uma proposta de sociedade bem ordenada

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    Jéssica de Farias Mesquita

    2017-02-01

    Full Text Available O presente texto tem como objetivo examinar a visão de John Rawls acerca das sociedades bem ordenadas na obra O Direito dos Povos, bem como o significado destas para o desenvolvimento da proposta de sociedade democrática liberal. Rawls, na primeira parte da obra, que trata sobre a teoria ideal, refere-se à ideia geral de contrato social nas Sociedades dos Povos democráticos liberais. O autor prossegue com a mesma ideia, na segunda parte da obra quando trata da teoria não-ideal, referindo-se aos povos decentes. Uma sociedade dos povos decentes, segundo Rawls, é uma sociedade cujas características são aceitáveis como membro de uma Sociedade dos Povos razoável, embora não seja uma sociedade democrática liberal. Ambas as sociedades, seja ela democrática liberal ou decente, fazem parte de uma sociedade bem ordenada por obedecerem aos critérios estabelecidos pela Sociedade dos Povos. Para a garantia de uma sociedade bem ordenada, Rawls expõe uma série de condições para que esse tipo de sociedade seja possível, uma dessas condições é o modo como essas sociedades se encontram reguladas.

  14. DISCURSO, IDENTIDADE E SUBJETIVIDADE EM O CANDIDATO DOS POBRES

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    WELISSON MARQUES

    2011-01-01

    Full Text Available Propomos por meio deste artigo refletir, a priori, acerca da noção de identidade advinda dos estudos sociológicos, seguindo as reflexões de Hall (2006, Bauman (2005, Silva (2007 e Woodward (2007, como também de subjetividade a partir dos estudos de Foucault (1984; 1992; 1994; 1997 2007, e pensar a pertinência destes conceitos como complementares e que coadunam com a noção de sujeito segundo a perspectiva discursiva. Apresentaremos também uma breve reflexão sobre a noção de poder em Foucault, cuja proficuidade se dá na Análise do Discurso uma vez que o poder é constitutivo dos discursos do sujeito-enunciador. Por fim, pautados nos conceitos aqui bosquejados, empreenderemos uma breve análise de um artigo intitulado O Candidato dos Pobres publicado pela revista Veja e que faz referência ao presidente Lula no contexto do escândalo do mensalão. Destarte, percebemos por meio dos recortes analisados que o sujeito enunciador se utiliza de diversas estratégias como forma de conspurcação de seu referente - o presidente Lula.

  15. Electrostaticspray preparation and properties of RDX/DOS composites

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    Jian Yao

    2017-08-01

    Full Text Available A composite explosive based on 1, 3, 5-trinitro-1, 3, 5-triazinane (RDX was prepared by electrostaticspray method with dioctyl sebacate (DOS as desensitizer. After preparation, the particle size and crystal structure were characterized and chemical features, such as chemical bonds, functional groups, thermal decomposition parameters and mechanical sensitivity were investigated as well. In terms of the morphologies of the composites, the particle sizes were in the range of 1–3 μm. Compared with RDX, the crystal types, chemical bonds and functional groups of the RDX/DOS composites were unchanged. The activation energy of the composites was lower than that of raw RDX, and the 3wt % DOS composites had the lowest activation energy. The impact sensitivity and friction sensitivity of the RDX/DOS composites were lower than those of raw RDX, and the 10wt% DOS composites had the highest H50 (125.9 cm and the lowest friction sensitivity (8%.

  16. Perspectivas para a pesquisa em contabilidade: o impacto dos derivativos

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    Alexsandro Broedel Lopes

    2001-08-01

    Full Text Available Este artigo analisa o impacto dos instrumentos financeiros derivativos para a pesquisa em contabilidade. O impacto dos derivativos é grande independentemente da linha de pesquisa adotada. Dentro do paradigma do mercado de capitais, o papel dos derivativos como antecipadores do comportamento futuro dos preços fornece oportunidades interessantes de investigação, por exemplo. Na linha de pesquisa institucional e social o tratamento contábil de tais instrumentos é visualizado tendo-se por base a busca por poder e legitimização da profissão. As características operacionais dos produtos, ambiente de regulamentação, evolução tecnológica e outros aspectos característicos fazem desses produtos bases promissoras para investigações futuras.This paper investigates the role of derivative financial instruments for the future of financial accounting research. This impact is relevant what all major research paradigms are concerned. In capital market-based research, derivative instruments play a central role in price discovery. From the institutional and social points-of-view, derivatives are components of a greater quest for legitimization and power. Their operational features, regulatory environment, technological advances and other characteristics are turning derivatives into promising research venues.

  17. Adsorption characteristics of Fe(III) and Fe(III)-NTA complex on granular activated carbon.

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    Kim, D S

    2004-01-02

    The adsorption of Fe(3+) ion on granular activated carbon has been studied in kinetic and equilibrium conditions taking into account the adsorbate concentration, temperature and solution pH as major influential factors. In addition, the effect of nitrilotriacetic acid on adsorption reaction as a complexing agent has been examined. Kinetic studies showed that the adsorption rate was increased as the initial Fe(3+) concentration was raised. The adsorption reaction was estimated to be first-order at room temperature. The adsorption rate and equilibrium adsorption of Fe(3+) increased as the temperature rose. The activation energy for adsorption was approximately 2.23 kJ mol(-1), which implied that Fe(3+) mainly physically adsorbed on activated carbon. Coexistence of nitrilotriacetic acid with Fe(3+) resulted in a decrease of equilibrium adsorption and the extent of decrease was proportional to the concentration of nitrilotriacetic acid. In the presence of nitrilotriacetic acid, the adsorbability of Fe(3+) decreased with pH. However, the trend was reversed in the absence of nitrilotriacetic acid. When activated carbon was swelled by acetic acid, the specific surface area was increased and maximum swelling was achieved at approximately 48 h of swelling time. Thermodynamic parameters such as DeltaG(o), DeltaH(o) and DeltaS(o) for adsorption reaction were estimated based on equilibrium data and in connection with these results the thermodynamic aspects of adsorption reaction were discussed.

  18. Thermodynamic Description Of Ternary Fe-B-X Systems. Part 2: Fe-B-Ni

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    Miettinen J.

    2014-06-01

    Full Text Available Przedstawiono termodynamiczny opis trójskładnikowego układu Fe-B-Ni w kontekście nowej bazy danych dla układów Fe-B-X (X = Cr, Ni, Mn, Si, Ti, V, C. Parametry termodynamiczne dwuskładnikowych stopów Fe-B. Fe-Ni i B-Ni zostały są zaczerpnięte z wcześniejszych opracowań, przy tym opis B-Ni został nieznacznie zmodyfikowany. Parametry dla układu Fe-B-Ni zostały zoptymalizowane w tej pracy w oparciu o eksperymentalne równowagi fazowe i dane termodynamiczne zaczerpnięte z literatury. Roztwory stałe w układzie Fe-B-Ni opisano przy użyciu modelu roztworu substytucyjnego, a borki traktowane są jako fazy stechiometryczne lub półstechiometryczne typu (A.BpCq opisane przy użyciu modelu dwu podsieci.

  19. Development of overcharge tolerance in Li/FeS and Li/FeS2 cells

    Science.gov (United States)

    Kaun, T. D.; Holifield, T. F.; Nigohosian, M.; Nelson, P. A.

    An innovative application of a self-discharge mechanism for molten-electrolyte Li-alloy/FeS(sub x) cells has led to the development of overcharge-tolerant cells. Conventional Li-alloy/FeS(sub x) battery cells require an electronic charger/equalizer. Two versions of the cell have been demonstrated: LiAl+10 mol percent Li5Al5Fe2/LiCl-LiBr-KBr (BN, MgO)/FeS2 (operated at 400 C) and LiAl+10 mol percent Li2Fe2/LiF-LiCl-LiBr(MgO)/FeS (operated at 475 C). These cells exhibit a unique combination of overcharge capacity and extended trickle-charge tolerance at 2--5 mA/cm. The basis for the self-discharge is diffusion of reduced lithium species across the separator by a lithium-shuttle mechanism that is controlled by the Li-activity of the Li-alloy electrode. A bimodal self-discharge rate (a 20-fold increase toward the end of charge) results from a 150--250 mV step increase in Li-activity. Cells having overcharge tolerance have operated with stable performance for greater than 200 cycles. The overcharge tolerance rates are sufficient for battery cells to exhibit built-in charge/equalization capability.

  20. Microstructural and Mechanical Properties of In Situ WC-Fe/Fe Composites

    Science.gov (United States)

    Zhong, Lisheng; Yan, Yinglin; Ovcharenko, Vladimir E.; Cai, Xiaolong; Zhang, Xi; Xu, Yunhua

    2015-11-01

    In this study, Fe matrix reinforced with column-shaped WC-Fe composite was designed and fabricated by a novel in situ method. The WC-Fe/Fe composite exhibited a similar structure to that of reinforced concrete. The microstructure, microhardness, impact toughness, and wear resistance of the composites were characterized using scanning electron microscopy, and x-ray diffraction, as well as microhardness, impact, and wear tests. Small amounts of graphite (G), α-Fe, and WC were the predominant phases in the reinforcing bar of the composites. WC particulates improved the wear resistance of the composite, and the highest wear resistance was 96 times higher than that of gray cast iron under a load of 20 N with SiC abrasive particles. The wear resistance mechanism involved protection of the matrix behind the WC bundles by hard carbides. The excellent fracture toughness of the composite was mainly attributed to the disappearance of G flakes from the Fe matrix because of the in situ reaction, which reduced the split action to the matrix. The matrix absorbed a large amount of the crack propagation energy.