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Sample records for hierro bandeado bif

  1. Chemostratigraphy of Neoproterozoic Banded Iron Formation (BIF)

    DEFF Research Database (Denmark)

    Gaucher, Claudio; Sial, Alcides N.; Frei, Robert

    2015-01-01

    Sawawin BIF (Saudi Arabia), and the Jucurutu Formation of the Seridó Belt (NE Brazil). Lake Superior type BIFs are represented by the Tonian Shilu Group (South China) and the late Ediacaran Arroyo del Soldado Group (Yerbal and Cerro Espuelitas formations, Uruguay). Useful chemostratigraphic tools...

  2. BIF butterfly valve life extension at WNP-2

    International Nuclear Information System (INIS)

    Armstrong, D.

    1991-01-01

    Primary containment purging, venting, inerting, and reactor building ventilation at the WNP-2 plant are accomplished with a series of large butterfly valves. A total of 31 valves which are similar in design, but of different sizes, employ an elastomer to achieve sealing integrity when closed. These valves, which were originally manufactured by BIF, a unit of General Signal, range in size from 18 to 84 inches in diameter. Service life in the plant was much less than desired for safety-related equipment, and several seal failures had been experienced shortly after valve overhaul. This program covers a design change made to enhance performance of the elastomer seal to achieve a very meaningful life extension. While numerous configurations of BIF valves exist, this work relates only to the model 657 unit assembled with an elastomer seal mounted onto the valve disc by a stainless steel clamping ring held with studs and nuts. The problems encountered, and the steps taken to resolve the deficiencies may, however, be applicable to other butterfly valve configurations

  3. Termination of BIF deposition in the Paleoproterozoic: the Tongwane Formation, South Africa

    OpenAIRE

    Schroeder, Stefan; Warke, Matthew

    2016-01-01

    The Tongwane Formation (~2.4 Ga) conformably overlies banded iron formations (BIF; Penge Iron Formation) on the Kaapvaal Craton, South Africa. As such, it provides a unique window into depositional processes and environmental conditions in the aftermath of major Archean-Paleoproterozoic BIF deposition, and on the eve of irreversible environmental oxygenation in the Great Oxidation Event (GOE, ~2.35 Ga). This study presents the first sedimentological and bulk-rock geochemical characterization ...

  4. Ingesta de hierro dietario en mujeres adolescentes de instituciones educativas

    Directory of Open Access Journals (Sweden)

    Mabel Vila

    2008-09-01

    Full Text Available Introducción: La anemia por deficiencia de hierro es un problema de salud pública. La baja ingesta de hierro dietario es una de sus causas. Objetivo: Estimar la ingesta de hierro dietario en mujeres adolescentes. Diseño: Estudio descriptivo, transversal. Lugar: Instituciones educativas del distrito de Ancón. Participantes: Trescientos cincuenticinco mujeres adolescentes estudiantes del nivel secundario, elegidas en forma aleatoria. Intervenciones: Previo consentimiento informado, se aplicó un cuestionario de frecuencia de consumo de alimentos y bebidas semicuantitativo. Principales medidas de resultados: Ingesta dietaria diaria de hierro. Resultados: La edad promedio de las adolescentes fue 14 ± 1,69 años. La mediana de ingesta dietaria de hierro fue 10,4 mg/día (cuartil 1= 9 mg/día, cuartil 3 =12,1 mg/día y la mediana de adecuación, 38,4% (cuartil 1 = 33,45%; cuartil 3 = 45,56%. El 86,8% de las adolescentes no cubrieron ni el 50% de sus recomendaciones diarias de hierro. El hierro de alta biodisponibilidad representó la décima parte del total del hierro ingerido. El pan y el arroz fueron los alimentos que más hierro aportaron a la dieta. Conclusiones: El 86,8 % de las adolescentes evaluadas mostró riesgo alto de ingesta inadecuada de hierro. La ingesta de hierro de alta biodisponibilidad fue baja.

  5. Thermal analysis and phase diagrams of the LiF BiF3 e NaF BiF3 systems

    International Nuclear Information System (INIS)

    Nakamura, Gerson Hiroshi de Godoy

    2013-01-01

    Investigations of the binary systems LiF-BiF 3 and NaF-BiF 3 were performed with the objective of clarifying the thermal behavior and phase equilibria of these systems and their intermediary phases, an important requisite for high-quality crystal growth. Several samples in the entire range of compositions (0 to 100 mol% BiF 3 ) of both systems were subjected to experiments of differential thermal analysis (DTA) and thermogravimetry (TG), and also of differential scanning calorimetry (DSC). A few specific compositions were selected for X-ray diffraction to supplement the experimental data. Due to the high vulnerability of BiF 3 to oxygen contamination, its volatility and propensity to destroy metal parts upon heating, it was necessary to determine the optimal conditions for thermal analysis before investigating the systems themselves. Phase relations in the system LiF-BiF 3 were completely clarified and a phase diagram was calculated and evaluated via the commercial software Factsage. The diagram itself consists in a simple peritectic system in which the only intermediary compound, LiBiF 4 , decomposes into LiF and a liquid phase. The NaF-BiF 3 system could not be completely elucidated and the phase relations in the NaF poor side (> 50% BiF 3 ) are still unknown. In the NaF rich side, however, the possible peritectoid decomposition of the compound NaBiF 4 was identified. In both systems X-ray diffraction yielded crystal structures discrepant with the literature for the intermediary phases, LiBiF 4 , NaBiF 4 and a solid solution of NaF and BiF 3 called I. The observed structures remain unknown and explanations for the discrepancies were proposed. (author)

  6. Ingesta de hierro dietario en mujeres adolescentes de instituciones educativas

    OpenAIRE

    Mabel Vila; Margot Quintana

    2008-01-01

    Introducción: La anemia por deficiencia de hierro es un problema de salud pública. La baja ingesta de hierro dietario es una de sus causas. Objetivo: Estimar la ingesta de hierro dietario en mujeres adolescentes. Diseño: Estudio descriptivo, transversal. Lugar: Instituciones educativas del distrito de Ancón. Participantes: Trescientos cincuenticinco mujeres adolescentes estudiantes del nivel secundario, elegidas en forma aleatoria. Intervenciones: Previo consentimiento informado, se aplicó un...

  7. Algoma-type Neoproterozoic BIFs and related marbles in the Seridó Belt (NE Brazil)

    DEFF Research Database (Denmark)

    Sial, Alcides N.; Campos, Marcel S.; Gaucher, Claudio

    2015-01-01

    The Jucurutu Formation in the Seridó Belt, northeastern Brazil, encompasses fine-to coarse-grained amphibolite-facies marbles, locally with cross-bedding and stromatolites. Banded iron formations (BIF) at three localities in this belt comprise itabirites (actinolite- or cummingtonite-itabirite an...

  8. Constraining the role of anoxygenic phototrophic Fe(II)-oxidizing bacteria in deposition of BIFs

    Science.gov (United States)

    Kappler, A.; Posth, N. R.; Hegler, F.; Wartha, E.; Huelin, S.

    2007-12-01

    Banded Iron Formations (BIFs) are Precambrian sedimentary deposits of alternating iron oxide and silica mineral layers. Their presence in the rock record ca.3.8-2.2 Ga makes them particularly intriguing formations for the debate over when oxygen became dominant on Earth. The mechanism(s) of BIF deposition is still unclear; suggestions including both abiotic and biotic processes. We are interested in constraining one of these proposed mechanisms; the direct biological oxidation of Fe(II) via anoxygenic Fe(II)-oxidizing autophototrophs. In order to find the limitations of photoferrotrophic BIF deposition, we take a holistic approach, investigating the oxidation of Fe(II) by modern Fe(II)-oxidizing phototrophs, the precipitation of Fe(III) (hydr)oxides, and the fate of the cell-mineral aggregates in the water column and at the basin floor. Specifically, physiology experiments with Fe(II)-oxidizing phototrophs under various conditions of light intensity, pH, Fe(II) concentration and temperature allow us to determine the environmental limits of such organisms. We carry out precipitation experiments to characterize the sedimentation rates, aggregate size and composition in order to resolve the effect of reactions in the water column. Finally, we simulate the diagenetic fate of these aggregates on the basin floor by placing them in gold capsules under T and P conditions relevant for the Transvaal Supergroup BIFs of South Africa. Recently, we have developed a tank simulating the Archean ocean in which the strains grow in continuous culture and collect the aggregates formed under various geochemical conditions. We aim to model the extent of and limitations to photoferrotrophs in BIF deposition. This information will help constrain whether biotic processes were dominant in the Archean ocean and will offer insight to the evolution of the early biogeosphere.

  9. EFECTO DEL CONSUMO DE PREBIOTICOS SOBRE LA BIODISPONIBILIDAD DE HIERRO

    OpenAIRE

    WEINBORN ASTUDILLO, VALERIE

    2009-01-01

    El hierro (Fe) es un elemento esencial para el ser humano, pero en exceso puede ser tóxico. La homeostasis de Fe es regulada por su absorción a través del enterocito. En la dieta el hierro se encuentra de dos formas: el hierro no hemínico (Fe-no hem) y el hierro hemínico (Fe-hem). La forma en que se encuentra el hierro en la dieta determina de cómo será absorbido. La absorción de Fe-no hem es influenciada por componentes intraluminales y dietarios: los taninos, fitatos y calcio disminuyen la ...

  10. Decoupling photochemical Fe(II) oxidation from shallow-water BIF deposition

    DEFF Research Database (Denmark)

    Konhauser, Kurt; Amskold, Larry; Lalonde, Stefan

    2007-01-01

    to the rise of atmospheric oxygen and the development of a protective ozone layer, the Earth's surface was subjected to high levels of ultraviolet radiation. Bulk ocean waters that were anoxic at this time could have supported high concentrations of dissolved Fe(II). Under such conditions, dissolved ferrous...... for biology [Fran??ois, L.M., 1986, Extensive deposition of banded iron formations was possible without photosynthesis. Nature 320, 352-354]. Here, we evaluate the potential importance of photochemical oxidation using a combination of experiments and thermodynamic models. The experiments simulate......-type systems, then we are driven to conclude that oxide-facies BIF are the product of a rapid, non-photochemical oxidative process, the most likely candidates being direct or indirect biological oxidation, and that a significant fraction of BIF could have initially been deposited as ferrous minerals. ?? 2007...

  11. Volviendo a pensar la Edad del Hierro

    Directory of Open Access Journals (Sweden)

    Hill, J. D.

    1993-12-01

    Full Text Available This paper argues there is an urgent need to critically evaluate the basic assumptions used by Iron Age archaeologists across Europe. It suggests that the existing frameworks of explanation and interpretation are at best inadequate to understand the actual archaeological evidence for the period. At worst they are still unconsciously reproducing nineteenth century nationalist and racist ideologies (e. g. the preoccupations with the «Celts≫ or «Iberians≫, etc.. Drawing on examples from Britain, and the Czech and Slovak republics. We will argue that archaeological evidence Iron the Iron Age does not neatly fit our modernist and Eurocentric assumptions about what the period ought to have been like. It suggests Iron Age archaeology must recognise the difference of the past, that prehistoric societies in Europe may have had very different forms of social organisations, world views and economies than those in later European history. This means critically questioning archaeological evidence and being open to the possibility that existing interpretations are wrong (e. g. stressing the impact of the Mediterranean World Economy, that Oppidas were urban centres, or that settlement and subsistence data can be adequately understood in modern capitalist/functionalist terms, etc.. As such Iron Age studies can on/y be a «Contextual Archaeology≫.

    Este artículo defiende la urgente necesidad de evaluar críticamente las asunciones básicas manejadas por los arqueólogos de la Edad del Hierro en toda Europa. Sugiere que los marcos explicativos e interpretativos existentes son, en el mejor de los casos, inadecuados para comprender la evidencia arqueológica real sobre el período. En el peor, están reproduciendo todavía las ideologías nacionalistas y racistas decimonónicas (p. e. las preocupaciones por los “Celtas”, los “Iberos”, etc.. A partir de ejemplos de Gran Bretaña, y las Repúblicas Checa y Eslovaca, sostenemos que la evidencia

  12. Biomarcadores del metabolismo y nutrición de hierro

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    Carmen Gloria Sermini

    Full Text Available RESUMEN La anemia por deficiencia de hierro continúa siendo la deficiencia nutricional más abundante en el mundo, y son los lactantes, preescolares, mujeres en edad fértil y embarazadas los grupos de mayor susceptibilidad. Debido a esto es que se hace necesario el conocer los mecanismos de regulación de captación, transporte y absorción del metal a nivel celular, principalmente a nivel del enterocito y, una vez que el hierro entra a la circulación, conocer cuáles son los biomarcadores que permiten realizar un seguimiento del estatus del hierro corporal. En esta revisión mostramos, en primer lugar, cómo se regula la entrada de hierro a nivel de la célula del epitelio intestinal, mostrando las principales proteínas involucradas (transportadores de entrada y salida de hierro, oxido-reductasas, proteína de almacenamiento y, para finalizar, hacemos un recuento de los principales biomarcadores del metabolismo de hierro una vez que este ha entrado y circula por el organismo.

  13. Motor de indução bifásico em rede de alimentação bifásica simétrica com condutor de retorno

    OpenAIRE

    Castro Neto, Lindolfo Marra de

    2006-01-01

    O objetivo principal deste trabalho é fornecer uma contribuição que ajudará no entendimento com maior profundidade sobre o funcionamento do motor de indução bifásico assimétrico com retorno para aplicações em locais onde exista a possibilidade de uma rede de alimentação bifásica. As contribuições mais importantes foram obtidas com o auxílio do modelo dinâmico no domínio do tempo para máquinas bifásicas simétricas e assimétricas desenvolvido neste trabalho. Através das ...

  14. Binary Format for Scene (BIFS): combining MPEG-4 media to build rich multimedia services

    Science.gov (United States)

    Signes, Julien

    1998-12-01

    In this paper, we analyze the design concepts and some technical details behind the MPEG-4 standard, particularly the scene description layer, commonly known as the Binary Format for Scene (BIFS). We show how MPEG-4 may ease multimedia proliferation by offering a unique, optimized multimedia platform. Lastly, we analyze the potential of the technology for creating rich multimedia applications on various networks and platforms. An e-commerce application example is detailed, highlighting the benefits of the technology. Compression results show how rich applications may be built even on very low bit rate connections.

  15. In-building Unlicensed WiFi Band OFDM Signal Distribution over MMF&BIF Using VCSEL

    DEFF Research Database (Denmark)

    Deng, Lei; Jensen, Jesper Bevensee; Yu, Xianbin

    2011-01-01

    For in-building applications, an OFDM-VCSEL RoF system operating in unlicensed WiFi band is experimentally tested using MMF and bend insensitive fiber (BIF). A spectral efficiency of 4.32 bit/s/Hz with 0.9 Gbps data rate is achieved....

  16. Biomarcadores del metabolismo y nutrición de hierro

    OpenAIRE

    Sermini, Carmen Gloria; Laboratorio de Micronutrientes, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile. Nutricionista; Acevedo, María José; Laboratorio de Micronutrientes, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile. Nutricionista; Arredondo, Miguel; Laboratorio de Micronutrientes, Instituto de Nutrición y Tecnología de los Alimentos, Universidad de Chile. Msc; Phd

    2017-01-01

    RESUMEN La anemia por deficiencia de hierro continúa siendo la deficiencia nutricional más abundante en el mundo, y son los lactantes, preescolares, mujeres en edad fértil y embarazadas los grupos de mayor susceptibilidad. Debido a esto es que se hace necesario el conocer los mecanismos de regulación de captación, transporte y absorción del metal a nivel celular, principalmente a nivel del enterocito y, una vez que el hierro entra a la circulación, conocer cuáles son los biomarcadores que per...

  17. Causas y consecuencias de la deficiencia de hierro

    Directory of Open Access Journals (Sweden)

    Olivares Manuel

    2004-01-01

    Full Text Available La deficiencia de hierro es la deficiencia nutricional más prevalente y la principal causa de anemia a escala mundial. Además de las manifestaciones propias de la anemia, se han descrito otras manifestaciones no hematológicas tales como: disminución de la capacidad de trabajo físico y de la actividad motora espontánea, alteraciones de la inmunidad celular y de la capacidad bactericida de los neutrófilos, disminución de la termogénesis, alteraciones funcionales e histológicas del tubo digestivo, falla en la movilización de la vitamina A hepática, mayor riesgo de parto prematuro, bajo peso de nacimiento y de morbilidad perinatal, menor transferencia de hierro al feto, una disminución de la velocidad de crecimiento, alteraciones conductuales y del desarrollo mental y motor, velocidad de conducción más lenta de los sistemas sensoriales auditivo y visual, y reducción del tono vagal. La prevención de la deficiencia de hierro incluye cambios en los hábitos alimentarios, fortificación de los alimentos y la suplementación con hierro.

  18. Synthesis of Er(III)/Yb(III)-doped BiF3 upconversion nanoparticles for use in optical thermometry.

    Science.gov (United States)

    Du, Peng; Yu, Jae Su

    2018-03-23

    The authors describe an ethylene glycol assisted precipitation method for synthesis of Er(III)/Yb(III)-doped BiF 3 nanoparticles (NPs) at room temperature. Under 980-nm light irradiation, the NPs emit upconversion (UC) emission of Er(III) ions as a result of a two-photon absorption process. The temperature-dependent green emissions (peaking at 525 and 545 nm) are used to establish an unambiguous relationship between the ratio of fluorescence intensities and temperature. The NPs have a maximum sensitivity of 6.5 × 10 -3  K -1 at 619 K and can be applied over the 291-691 K temperature range. The results indicate that these NPs are a promising candidate for optical thermometry. Graphical abstract Schematic of the room-temperature preparation of Er(III)/Yb(III)-doped BiF 3 nanoparticles with strongly temperature-dependent upconversion emission.

  19. Efectos de la deficiencia de hierro en el funcionamiento intelectual

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    Ernesto Pollitt

    2013-09-01

    Full Text Available El propósito de este trabajo es el de presentar un análisis comparativo de los resultados de seis investigaciones en las cuales ha participado el autor sobre la relación entre la deficiencia de hierro y el funcionamiento intelectual. Las investigaciones fueron realizadas en Egipto, Estados Unidos, Guatemala, Indonesia y Tailandia entre niños de edad pre-escolar. La deficiencia de hierro con anemia está entre las dos deficiencias nutricionales más prevalentes en el mundo y es de esperar que su prevalencia sea alta en el Perú, particularmente entre los infantes y niños y entre las madres gestantes y lactantes. Una de las causas importantes es el limitado consumo de alimentos ricos en hierro hemínico que generalmente son muy costosos para los grupos más pobres de la sociedad. El análisis comparativo muestra que los resultados son consistentes a través de los seis estudios y que la deficiencia de hierro con anemia afecta el rendimiento en las pruebas de procesos cognoscitivos específicos y en las pruebas de rendimiento escolar. Los resultados también muestran que dichos efectos son reversibles con el tratamiento apropiado. A su vez, el análisis muestra que no hay evidencia suficiente para inferir que la deficiencia de hierro sin anemia afecta el cociente intelectual.   The purpose of this paper is to present a comparative analysis of the results of six researches in which the author has participated, about the relation between iron deficiency and intellectual performance. The researches were carried out in Egypt, U.S.A., Guatemala, Indonesia and Thailand, with pre-school and school children. Iron deficiency with anemia are among the two nutritional deficiencies of major prevalence in the word and it must be expected that the same goes for Peru. One of the causes of the low consuming of food rich in iron is that these are too expensive for groups of low socioeconomic level. The comparative analysis shows consistent results in the six

  20. Absorción de hierro en "Maca" lepidum meyenii walp. (Brasicaceae

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    Mery L. Suni

    2013-06-01

    Full Text Available Lepidium meyenii Walp (Brasicaceae “maca” es una planta andina apreciada por sus hipocótilos de alto valor medicinal y nutritivo, entre estos, su elevado contenido de hierro. Para determinar la posibilidad de incrementarlo se llevó a cabo un experimento en invernadero, en Lima, durante el periodo de mayo a noviembre de 1999, en el cual se proporcionó tres niveles de hierro natural (5, 15 y 25 ppm en soluciones nutritivas. Se utilizaron semillas, entrada ARB5441 (CIP. Se determinó el contenido de hierro a los 50 y 179 días después del tratamiento (ddt por el método de fenantrolina. Se encontró diferencias significativas en el contenido de hierro en hojas e hipocótilo a los 50 ddt, incrementado este en relación a la cantidad de hierro suministrada, mientras que a los 179 ddt esta misma respuesta se observa sólo a nivel de hojas. La concentración de hierro obtenida en el hipocótilo para cada tratamiento no incrementó en el tiempo mientras que en la hoja sí. En general los valores de concentración de hierro obtenidos son mayores a los reportados en la literatura. El peso de la planta tendió a disminuir en relación al nivel de hierro a los 50 ddt, pero a los 179 ddt tendió a incrementar. En función al tiempo, el peso de los hipocótilos en cada tratamiento incrementó notablemente; mientras que las hojas, ligeramente. Los resultados obtenidos nos permiten señalar que un nivel de 5 ppm de hierro resulta adecuado y suficiente para obtener concentraciones altas de hierro en los hipocótilos de “maca”.

  1. Geochronological constraints on the evolution of El Hierro (Canary Islands)

    Science.gov (United States)

    Becerril, Laura; Ubide, Teresa; Sudo, Masafumi; Martí, Joan; Galindo, Inés; Galé, Carlos; Morales, Jose María; Yepes, Jorge; Lago, Marceliano

    2016-01-01

    New age data have been obtained to time constrain the recent Quaternary volcanism of El Hierro (Canary Islands) and to estimate its recurrence rate. We have carried out 40Ar/39Ar geochronology on samples spanning the entire volcanostratigraphic sequence of the island and 14C geochronology on the most recent eruption on the northeast rift of the island: 2280 ± 30 yr BP. We combine the new absolute data with a revision of published ages onshore, some of which were identified through geomorphological criteria (relative data). We present a revised and updated chronology of volcanism for the last 33 ka that we use to estimate the maximum eruptive recurrence of the island. The number of events per year determined is 9.7 × 10-4 for the emerged part of the island, which means that, as a minimum, one eruption has occurred approximately every 1000 years. This highlights the need of more geochronological data to better constrain the eruptive recurrence of El Hierro.

  2. Mode switching in volcanic seismicity: El Hierro 2011-2013

    Science.gov (United States)

    Roberts, Nick S.; Bell, Andrew F.; Main, Ian G.

    2016-05-01

    The Gutenberg-Richter b value is commonly used in volcanic eruption forecasting to infer material or mechanical properties from earthquake distributions. Such studies typically analyze discrete time windows or phases, but the choice of such windows is subjective and can introduce significant bias. Here we minimize this sample bias by iteratively sampling catalogs with randomly chosen windows and then stack the resulting probability density functions for the estimated b>˜ value to determine a net probability density function. We examine data from the El Hierro seismic catalog during a period of unrest in 2011-2013 and demonstrate clear multimodal behavior. Individual modes are relatively stable in time, but the most probable b>˜ value intermittently switches between modes, one of which is similar to that of tectonic seismicity. Multimodality is primarily associated with intermittent activation and cessation of activity in different parts of the volcanic system rather than with respect to any systematic inferred underlying process.

  3. La funcionalidad de los óxidos de hierro

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    Castaño, J. G.

    1998-06-01

    Full Text Available Some iron oxides have a great scientific and technological possibilities, not only for their importance in the present, but also for their great potential in the development of the future technologies. They have adequate properties to carry out several functions. They are plentiful in the nature and their synthetic obtention is not complex. This paper shows five of them (hematite, magnetite, maghemite, goethite and akaganeite and their utilization in fields like chemical industry, biotechnology, medicine, new materials and electromagnetism.

    Algunos óxidos de hierro tienen aplicaciones interesantes para las tecnologías actuales y futuras. Aparte de poseer propiedades adecuadas para cumplir diversas funciones, son relativamente abundantes en la naturaleza o su obtención en forma sintética no es complicada. En este artículo se presentan cinco de ellos (hematita, magnetita, maghemita, goethita y akaganeíta y su utilización en campos como la industria química, la biotecnología, la medicina, los nuevos materiales y el electromagnetismo.

  4. Graciela Hierro: Philosophy of Education in Gender Code

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    Georgina Aimé Tapia González

    2016-11-01

    Full Text Available The development of feminist theory and gender studies in Mexico cannot be understood without the work of Graciela Hierro. The aim of this article is to show the lasting value of her ethical proposal for a feminist education, as well as recognizing her contributions. I will deal with this in three sections: in the first one I will present her feminist ethics as a foundation of an education for women; in the second I will carry out a brief historical review of the philosophy of education from the viewpoint of Mexican female philosophers, and in the third, I will show the practical implications of the ethics of pleasure in women formation, from childhood to old age. My principal thesis is that Hierro’s ethics constitute the fundamentals for a philosophy of education that originates from feminist geneaology to Mexican culture through the visibilization of the legacy of local thinkers, that, from different standpoints, have reflected upon the “female question”.

  5. La arquitectura del hierro en España durante el siglo XIX

    OpenAIRE

    Navascués Palacio, Pedro; Calvo Serraller, Francisco

    1980-01-01

    Cuando el arquitecto neoclásico Silvestre Pérez, formado en la Academia de Bellas Artes y pensionado en Roma, recibe el encargo del ayuntamiento de Sevilla (1824) para hacer un proyecto de un puente sobre el Guadalquivir, éste se ve postergado al optarse por otro en hierro según se había experimentado ya en Inglaterra y Francia. Este hecho pone de relieve la forma violenta con que el hierro irrumpe en nuestra historia de la construcción, como fenómeno mimético, al margen de la lenta maduració...

  6. COMPUESTOS DE HIERRO PARA SUPLEMENTACIÓN ORAL: PRINCIPIOS Y AVANCES -REVISIÓN SISTEMATICA

    OpenAIRE

    PEREZ M, Lina J.; TOBÓN, Gloria

    2006-01-01

    Se presenta una revisión que abarca los principales aspectos sobre la absorción oral del hierro (fuentes y captación) y sus funciones en el organismo, centrándose en la tendencia actual de utilizar complejos o quelatos de este metal con ligandos orgánicos para el tratamiento oral por deficiencia del mismo (monosacáridos, aminoácidos y ácidos carboxílicos de bajo peso molecular), ya que estos compuestos aumentan la biodisponibilidad del hierro y disminuyen los efectos adversos que presentan su...

  7. Can el Hierro be 100% electric-renewable?

    International Nuclear Information System (INIS)

    Flocard, Hubert

    2016-01-01

    This summer, the media have abundantly reported that the el-Hierro island in the Canaries could now count on a 100 % renewable electric mix. As a matter of fact, these reports were based on only two hours during which the Gorona del Viento (GdV) installation managed to reach the objectives announced in the project document. Full of enthusiasm, Segolene Royal, the French minister of environment and energy, rewarded the project on behalf of the 'Syndicat des energies Renouvelables' What is the situation today for this installation inaugurated in June 2014? a considerable investment, leading to a complex system with more than 34 MW of installed production power (diesel, wind and hydraulic turbines, each for about one third) when the peak electric demand is only 7.6 MW that is a factor four less. The reality of the performances after six months of effective exploitation: the renewable fraction for the three most favourable months, July to September, has been 42 %. For the half year, the figure is even more disappointing with only 30 % renewables. The reasons behind these very modest performances with respect to the announced goal, which, moreover for the year 2015, lead to a considerable cost of the renewable MWh which is going to cost four times more than the MWh produced by the diesel plant and a cost of the avoided CO 2 exceeding 1000 Euro/ton? As shown in this document, they are first the limited wind resource, which according to data could not have allowed a renewable fraction larger than 50 % and second, the nature of the contract signed by the Spanish state which does not encourage GdV to strive for the optimal environmental performances. To summarize: unrealistic objectives, deplorable governance and a technical semi-failure very costly for the Spanish citizen. (author)

  8. Tres nuevos poblados de la Edad del Hierro en la Protohistoria de Gipuzkoa.

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    Carlos Olaetxea

    1991-01-01

    Full Text Available Se presenta el descubrimiento de tres nuevos poblados de la Edad del Hierro para la provincia de Gipuzkoa. Su importancia estriba en que hasta el presente sólamente se conocía uno, el de Intxur   (Tolosa - Albiztur, y en que han sido descubiertos dentro de un plan sistemático de prospecciones.

  9. Estudio de la adición de estabilizantes y vitamina B12 al complejo inyectable de hierro dextrana

    OpenAIRE

    Georgina Michelena; Antonio Bell; Graciela Cerutti; Emilia Carrera; Mónica Coronel; Gracia Rivas Monte

    2007-01-01

    Se realizó el estudio de adición de estabilizantes al complejo hierro dextrana mediante un diseño experimental 33 tipo mezcla con el objetivo de aumentar la fijación del hierro en el proceso de síntesis y disminuir su viscosidad, lo que incide favorablemente en la tecnología al obtener un producto de mayor filtrabilidad y con alto contenido de hierro. Los mejores resultados se alcanzaron con la variante de adición en iguales relaciones de ácido cítrico y sorbitol y tres veces la cantidad en d...

  10. Aumento de los depósitos de hierro y su relación con la enfermedad cardiovascular

    OpenAIRE

    Tomás Meroño; Patricia Sorroche; Fernando D. Brites

    2011-01-01

    En los últimos años, se ha avanzado considerablemente en el control de varios de los denominados factores de riesgo aterogénico tradicionales, a pesar de lo cual la incidencia de la enfermedad cardiovascular (ECV) continúa siendo elevada. Entre las diversas condiciones asociadas a ECV, podría ubicarse también a la sobrecarga de hierro. Su estudio ha cobrado relevancia desde que se planteó la "hipótesis del hierro", la cual postula que bajos niveles de hierro ejercerían un efecto protector del...

  11. Full-Vector Geomagnetic Field Records for the Late Quaternary from El Hierro and the Eifel

    Science.gov (United States)

    Monster, M.; de Groot, L. V.; Dekkers, M. J.; van Galen, J. P.; Kuiper, K.; Langemeijer, J.; Wiarda, L. R.

    2015-12-01

    Twenty-eight flows in the age range of c. 100 to c. 500 ka were sampled on the island of El Hierro (Canary Islands, Spain) and twelve in the Eifel (Germany). All sites from the Eifel had been previously dated, whereas the ages of the El Hierro flows were approximated by stratigraphic and directional coherency with a dated section c. 4 km to the north-east. Additionally, seven flows were dated using the ThermoFisher Helix multi-collector mass spectrometer at VU University Amsterdam (the Netherlands). The rocks were subjected to standard rock magnetic and palaeomagnetic experiments. Palaeodirections were obtained using both thermal and alternating-field demagnetisation techniques. Apart from two sites that appear to have been struck by lightning, all sites yielded reliable palaeodirections. Absolute palaeointensities were obtained using three different methods: IZZI-Thellier, the multispecimen protocol and the calibrated pseudo-Thellier technique. Nineteen sites from El Hierro and all twelve sites from the Eifel passed the selection criteria for one or more of these methods, with the pseudo-Thellier technique having the highest success rate (c. 35% for El Hierro and 55% for the Eifel). The palaeointensities obtained for El Hierro were mostly between 20 and 40 μT and for the Eifel between 20 and 50 μT, both with a tendency to be somewhat low compared to the present-day field of c. 39 μT and c. 49 μT, respectively. The pseudo-Thellier and multispecimen methods generally yielded lower palaeointensities than IZZI-Thellier, but no clear trend was visible.

  12. Spatial vent opening probability map of El Hierro Island (Canary Islands, Spain)

    Science.gov (United States)

    Becerril, Laura; Cappello, Annalisa; Galindo, Inés; Neri, Marco; Del Negro, Ciro

    2013-04-01

    The assessment of the probable spatial distribution of new eruptions is useful to manage and reduce the volcanic risk. It can be achieved in different ways, but it becomes especially hard when dealing with volcanic areas less studied, poorly monitored and characterized by a low frequent activity, as El Hierro. Even though it is the youngest of the Canary Islands, before the 2011 eruption in the "Las Calmas Sea", El Hierro had been the least studied volcanic Island of the Canaries, with more historically devoted attention to La Palma, Tenerife and Lanzarote. We propose a probabilistic method to build the susceptibility map of El Hierro, i.e. the spatial distribution of vent opening for future eruptions, based on the mathematical analysis of the volcano-structural data collected mostly on the Island and, secondly, on the submerged part of the volcano, up to a distance of ~10-20 km from the coast. The volcano-structural data were collected through new fieldwork measurements, bathymetric information, and analysis of geological maps, orthophotos and aerial photographs. They have been divided in different datasets and converted into separate and weighted probability density functions, which were then included in a non-homogeneous Poisson process to produce the volcanic susceptibility map. Future eruptive events on El Hierro is mainly concentrated on the rifts zones, extending also beyond the shoreline. The major probabilities to host new eruptions are located on the distal parts of the South and West rifts, with the highest probability reached in the south-western area of the West rift. High probabilities are also observed in the Northeast and South rifts, and the submarine parts of the rifts. This map represents the first effort to deal with the volcanic hazard at El Hierro and can be a support tool for decision makers in land planning, emergency plans and civil defence actions.

  13. Formación y estabilidad de chorros coaxiales bifásicos: aplicación a la generación de burbujas

    OpenAIRE

    Sevilla Santiago, Alejandro

    2011-01-01

    Las corrientes laminares libres en configuración de cofiujo aparecen en multitud de pro cesos naturales y aplicaciones de interés ingenieril. En esta Tesis se estudian ciertos aspectos novedosos en relación con la formación y la estabilidad de chorros coaxiales bifásicos, de particular relevancia en sistemas como reactores químicos o técnicas ac tuales de procesado de materiales. Existen diversos mecanismos, poco explorados hasta la fecha, que influencian la dinámica de los chorros coaxiales ...

  14. Estudo do equilíbrio líquido – líquido em sistemas aquosos bifásicos formados por polietilenoglicol (1500, 3350 e 6000), sais de fosfato e água em diferentes temperaturas

    OpenAIRE

    Silva, Angélica Siqueira da

    2014-01-01

    No presente trabalho, foram estudados os dados de equilíbrio de fases dos sistemas aquosos bifásicos formados por polietilenoglicol (1500, 3350 e 6000) + fosfato monobásico e dibásico de sódio (pH 7) + água. Estudou-se o efeito da variação da temperatura (10, 25 e 40°C) bem como da massa molar sobre os dados de equilíbrio. Para o PEG 3350 observou-se um aumento da área bifásica com diminuição da temperatura, mostrando que a formação do sistema aquoso bifásico é exotérmico. Para o PEG 1500 e 6...

  15. Aumento de los depósitos de hierro y su relación con la enfermedad cardiovascular

    Directory of Open Access Journals (Sweden)

    Tomás Meroño

    2011-12-01

    Full Text Available En los últimos años, se ha avanzado considerablemente en el control de varios de los denominados factores de riesgo aterogénico tradicionales, a pesar de lo cual la incidencia de la enfermedad cardiovascular (ECV continúa siendo elevada. Entre las diversas condiciones asociadas a ECV, podría ubicarse también a la sobrecarga de hierro. Su estudio ha cobrado relevancia desde que se planteó la "hipótesis del hierro", la cual postula que bajos niveles de hierro ejercerían un efecto protector del sistema cardiovascular. No obstante, hasta el presente, los resultados de los estudios diseñados para probar esta hipótesis han sido controversiales. Por otro lado, se lograron numerosos avances en el conocimiento del metabolismo del hierro a partir del descubrimiento de la hormona reguladora hepcidina. Los estudios sobre las funciones fisiológicas de esta hormona permitieron elaborar nuevas hipótesis que explican los resultados de los estudios clínicos anteriormente concebidos como contradictorios. El objetivo de la presente actualización es exponer, a la luz de los últimos avances sobre la regulación del metabolismo del hierro y su vinculación con la inflamación, el estado actual del conocimiento sobre el posible rol del exceso de hierro como factor de riesgo de ECV.

  16. Eficacia del hierro aminoquelado en comparación con el sulfato ferroso como fortificante de un complemento alimentario en preescolares con deficiencia de hierro, Medellín, 2011

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    Maylen Liseth Rojas

    2013-09-01

    Full Text Available Introducción. La disminución de los depósitos de hierro constituye el primer eslabón de la cadena conducente a la deficiencia de hierro, la carencia nutricional más prevalente y principal causa de anemia en todo el mundo, situación que puede prevenirse mediante la fortificación de alimentos. Objetivo. Comparar la eficacia del hierro aminoquelado con el sulfato ferroso como fortificante de un complemento alimentario en preescolares con deficiencia de hierro. Materiales y métodos. Se llevó a cabo un ensayo clínico triple ciego con distribución aleatoria de grupos. Se analizaron 56 preescolares con deficiencia de hierro (ferritina menor de 24 ng/ml a los que se les dio diariamente 13 g de leche con 12,5 mg de hierro. Después de dos meses se midieron los niveles de hemoglobina, hematocrito y ferritina sérica. Resultados. En el grupo con sulfato ferroso la concentración de ferritina sérica aumentó de 18,8 a 24,1ng/ml, mientras que dicha variación fue de 18,4 a 29,7 ng/ml con el hierro aminoquelado, en ambos casos con diferencias significativas. El nivel de ferritina final difirió según el grupo de estudio, siendo mayor en el grupo con hierro aminoquelado (p=0,022. La hemoglobina y el hematocrito no variaron después de la intervención. Las reacciones adversas en el grupo con sulfato ferroso fueron de 35,7 %, en contraste con el 42,9 % en el grupo con hierro aminoquelado; cinco niños presentaron infección delas vías respiratorias, sin diferencias estadísticas. Conclusiones. Los dos compuestos aumentan los niveles de ferritina, siendo mayor el aumento entre quienes toman leche con hierro aminoquelado. No fue diferente la incidencia de reacciones adversas o de infecciones entre los grupos. Identificador en Clinicaltrials.gov: NCT01412723 doi: http://dx.doi.org/10.7705/biomedica.v33i3.775

  17. Early signs of geodynamic activity before the 2011–2012 El Hierro eruption

    OpenAIRE

    López, Carmen; García-Cañada, Laura; Martí Molist, Joan; Domínguez Cerdeña, I.

    2016-01-01

    The potential relation between mantle plume dynamics, regional tectonics and eruptive activity in the Canary Islands has not been studied yet through the analysis of long-time series of geophysical observational data. The existence of highly reliable seismic and geodetic data has enabled us to study from 1996 to 2014 the geodynamic evolution of the North Atlantic Azores-Gibraltar region (including the NW African margin) and its relationship with recent volcanic activity in El Hierro (Canary I...

  18. Melt inclusion study of the most recent basanites from El Hierro and Lanzarote, Canary Islands

    Science.gov (United States)

    Gomez-Ulla, Alejandra; Sigmarsson, Olgeir; Huertas, Maria Jose; Ancochea, Eumenio

    2015-04-01

    The latest eruptions of both Lanzarote (one of the oldest and easternmost of the Canary Island archipelago) and El Hierro (the youngest and westernmost) produced basanite lavas. Major, volatile and trace element concentrations of melt inclusion (MI) hosted in olivine for both eruptions have been analysed. The basanites display primitive mantle normalized trace element spectra suggesting a magma source largely composed of recycled oceanic crust. In addition, beneath Lanzarote an interaction with a carbonatitic fluid phase or metasome would explain eccentric Ba/U and other trace element ratios. Contribution of carbonatitic component would readily account for extremely volatile-rich (Cl, F, S) MI from Lanzarote (Cl=1577-2500 ppm) whereas the maximum for El Hierro is 1080 ppm. The submarine character of the 2011-12 eruption off El Hierro appears to have affected the degassing behavior, whereas estimated sulfur emission to the atmosphere during the historical Lanzarote eruptions are amongst the highest observed so far. An estimated magma volume (VDRE) of 0.02 km3 yields atmospheric mass loading of 0.2 Mt SO2 from the 1824 Lanzarote eruption. Scaling the volume of the 1824 Lanzarote eruption to that of the previous Timanfaya eruption (1730-6; 5 km3) results in estimated 12 Mt SO2, an atmospheric mass loading only outnumbered by the historical Laki and Eldgjá eruptions in Iceland. The significantly greater volatile budget of basanites from Lanzarote compared to El Hierro is thus controlled by more fertile source composition closer to the African continent.

  19. Rosario Castellanos y Graciela Hierro: La reconfiguración de arquetipos femeninos

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    Krishna Naranjo Zavala

    2016-07-01

    Full Text Available Rosario Castellanos (1925-1974 y Graciela Hierro (1928-2003 sobresalieron en el feminismo en México. Ambas reflexionan que, a lo largo de la historia, las mujeres han sido representadas de manera peyorativa, carentes de voz propia y envueltas en ideas románticas. Referencias que han forjado concepciones en torno a la condición femenina; sin embargo, a través de la literatura y la filosofía, pueden ser replanteadas. El artículo se propone establecer un diálogo entre sus respectivos trabajos, Castellanos en la poesía y Hierro en la filosofía, tomando como base: Mujer que sabe latín (1973, el poema “La muerte de Dido” (1953-1955 y planteamientos de Ética y Feminismo (1985, De la domesticación a la educación de las mexicanas (1993, Ética de la libertad (1993 a fin de identificar la reconfiguración de arquetipos femeninos. Rosario Castellanos (1925-1974 and Graciela Hierro (1928-2003 stand out in feminism in Mexico. Both reflect that, throughout history, women have been represented pejoratively, with no voice, and wrapped in romantic ideas. References that have shaped ideas around the female condition; however through literature and philosophy, can be reframed. This paper aims to establish a dialogue between their respective works, Castellano´s in poetry and Hierro´s in philosophy, in order to identify the reconfiguration of female, religious and mythical archetypes in Mujer que sabe latín (1973, the poem “La muerte de Dido” (1953-1955; for this purpose it will be used the approaches on which Ética y Feminismo (1985, De la domesticación a la educación de las mexicanas (1993, and Ética de la libertad (1993 are based.

  20. La anemia por deficiencia de hierro: estrategias de la OPS/OMS para combatirla

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    FREIRE WILMA B

    1998-01-01

    Full Text Available La anemia por deficiencia de hierro es uno de los problemas nutricionales de mayor magnitud en el mundo. A pesar de conocer su etiología y tener a disposición el conocimiento de cómo enfrentarla y de saber que las intervenciones son de bajo costo, aún no se ha podido superar este problema. Este documento parte de una estimación de la magnitud del problema y plantea los elementos necesarios para el diseño, la ejecución y la medición del impacto de la suplementación con hierro y la fortificación, como las intervenciones más efectivas para disminuir considerablemente la dimensión de la anemia por falta de hierro. Propone una lista de pasos a seguir previos a la elaboración de un proyecto y recomienda una serie de elementos a considerar en ello. Define, asimismo, los aspectos que se deben incluir en una propuesta de fortificación y en otra de suplementación. El documento concluye con un listado de actividades complementarias que la Organización Panamericana de la Salud/Organización Mundial de la Salud ofrece dentro de su paquete de cooperación técnica.

  1. Structural interpretation of El Hierro (Canary Islands) rifts system from gravity inversion modelling

    Science.gov (United States)

    Sainz-Maza, S.; Montesinos, F. G.; Martí, J.; Arnoso, J.; Calvo, M.; Borreguero, A.

    2017-08-01

    Recent volcanism in El Hierro Island is mostly concentrated along three elongated and narrow zones which converge at the center of the island. These zones with extensive volcanism have been identified as rift zones. The presence of similar structures is common in many volcanic oceanic islands, so understanding their origin, dynamics and structure is important to conduct hazard assessment in such environments. There is still not consensus on the origin of the El Hierro rift zones, having been associated with mantle uplift or interpreted as resulting from gravitational spreading and flank instability. To further understand the internal structure and origin of the El Hierro rift systems, starting from the previous gravity studies, we developed a new 3D gravity inversion model for its shallower layers, gathering a detailed picture of this part of the island, which has permitted a new interpretation about these rifts. Previous models already identified a main central magma accumulation zone and several shallower high density bodies. The new model allows a better resolution of the pathways that connect both levels and the surface. Our results do not point to any correspondence between the upper parts of these pathways and the rift identified at the surface. Non-clear evidence of progression toward deeper parts into the volcanic system is shown, so we interpret them as very shallow structures, probably originated by local extensional stresses derived from gravitational loading and flank instability, which are used to facilitate the lateral transport of magma when it arrives close to the surface.

  2. Early signs of geodynamic activity before the 2011-2012 El Hierro eruption

    Science.gov (United States)

    López, Carmen; García-Cañada, Laura; Martí, Joan; Domínguez Cerdeña, Itahiza

    2017-04-01

    The potential relation between mantle plume dynamics, regional tectonics and eruptive activity in the Canary Islands has not been studied yet through the analysis of long-time series of geophysical observational data. The existence of highly reliable seismic and GNSS data has enabled us to study from 1996 to 2014 the geodynamic evolution of the North Atlantic Azores-Gibraltar region and its relationship with recent volcanic activity in El Hierro (Canary Islands, Spain). We compiled a new and unified regional seismic catalog and used long time-series of surface displacements recorded by permanent GNSS stations in the region. A regional- and local-scale analysis based on these data enabled us to identify signs of anomalous tectonic activity from 2003 onwards, whose intensity increased in 2007 and finally accelerated three months before the onset of the volcanic eruption on El Hierro in October 2011. This activity includes a regional extension and an uplift process that affects the southern Iberian Peninsula, NW Africa, and the Canary Islands. We interpret these observations as early signs of the geodynamic activity, which led to El Hierro eruption and the subsequent episodes of magma intrusion. Results point to the significant contribution of the mantle plume dynamics (i.e. external forces) in this renewed volcanic activity in the Canary Islands and emphasize the role of mantle dynamics in controlling regional tectonics.

  3. Magmatic sill intrusions beneath El Hierro Island following the 2011-2012 submarine eruption

    Science.gov (United States)

    Benito-Saz, María Á.; Sigmundsson, Freysteinn; Parks, Michelle M.; García-Cañada, Laura; Domínguez Cerdeña, Itahiza

    2016-04-01

    El Hierro, the most southwestern island of Canary Islands, Spain, is a volcano rising from around 3600 m above the ocean floor and up to of 1500 m above sea level. A submarine eruption occurred off the coast of El Hierro in 2011-2012, which was the only confirmed eruption in the last ~ 600 years. Activity continued after the end of the eruption with six magmatic intrusions occurring between 2012-2014. Each of these intrusions was characterized by hundreds of earthquakes and 3-19 centimeters of observed ground deformation. Ground displacements at ten continuous GPS sites were initially inverted to determine the optimal source parameters (location, geometry, volume/pressure change) that best define these intrusions from a geodetic point of view. Each intrusive period appears to be associated with the formation of a separate sill, with inferred volumes between 0.02 - 0.3 km3. SAR images from the Canadian RADARSAT-2 satellite and the Italian Space Agency COSMO-SkyMed constellation have been used to produce high-resolution detailed maps of line-of-sight displacements for each of these intrusions. These data have been combined with the continuous GPS observations and a joint inversion undertaken to gain further constraints on the optimal source parameters for each of these separate intrusive events. The recorded activity helps to understand how an oceanic intraplate volcanic island grows through repeated sill intrusions; well documented by seismic, GPS and InSAR observations in the case of the El Hierro activity.

  4. Relación entre las reservas de hierro maternas y del recién nacido

    Directory of Open Access Journals (Sweden)

    Vásquez-Molina María Eugenia

    2001-01-01

    Full Text Available Objetivo. Determinar la relación de los valores hematológicos maternos y neonatales en casos de reservas maternas de hierro bajas, moderadas y normales. Material y métodos. Diseño transversal en el que se incluyó a 163 mujeres embarazadas y sus neonatos de término, derechohabientes del Hospital de Ginecología y Obstetricia número 15 del Instituto Mexicano del Seguro Social (IMSS en Chihuahua, Chih., México. Se analizaron antecedentes maternos. Se determinaron niveles de hemoglobina, hematocrito y ferritina sérica en muestras maternas y de cordón umbilical. Se definieron reservas de hierro maternas de acuerdo a ferritina (µg /l: bajas o = 20.1. Se utilizó la prueba de Kruskal Wallis para establecer diferencias entre grupos, ji cuadrada para diferencia de proporciones y r de Pearson para establecer la relación entre reservas de hierro maternas y del recién nacido. Resultados. Se determinó una débil correlación entre la ferritina materna y neonatal r=0.14 (p=0.07. Las medias geométricas de ferritina neonatal respecto a las reservas maternas bajas, moderadas y normales fue de 4.77, 4.85 y 5.02, respectivamente (p=0.12. Las reservas de hierro maternas se modificaron con el suplemento de hierro (p=0.01. Conclusiones. Las reservas de hierro en el recién nacido están en estrecha relación con las maternas. Las mujeres que toman suplementos con hierro durante la gestación tienen reservas mayores al final del embarazo. El texto completo en inglés de este artículo está disponible en: http://www.insp.mx/salud/index.html

  5. High-grade iron ore at Windarling, Yilgarn Craton: a product of syn-orogenic deformation, hypogene hydrothermal alteration and supergene modification in an Archean BIF-basalt lithostratigraphy

    Science.gov (United States)

    Angerer, Thomas; Hagemann, Steffen G.; Danyushevsky, Leonid

    2013-08-01

    Banded iron formation (BIF)-hosted iron ore deposits in the Windarling Range are located in the lower greenstone succession of the Marda-Diemals greenstone belt, Southern Cross domain, Yilgarn Craton and constitute a total hematite-martite-goethite ore resource of minimum 52 Mt at 60 wt.% Fe (0.07 P). Banded iron formation is interlayered with high-Mg basalts at Windarling and precipitated during episodes of volcanic quiescence. Trace element content and the rare earth element (REE) ratios Y/Ho (42 to 45), Sm/Yb (1.5), together with positive La and Gd anomalies in `least-altered' hematite-magnetite-metachert-BIF indicate the precipitation from Archean seawater that was fertilised by hydrothermal vent fluids with a basaltic HREE-Y signature. Hypogene iron ore in sub-greenschist facies metamorphosed BIF formed during three distinct stages: ore stage 1 was a syn- to post-metamorphic, syn-D1, Fe-Ca-Mg-Ni-Co-P-REE metasomatism that produced local Ni-REE-rich Fe-dolomite-magnetite alteration in BIF. Hydrothermal alteration was induced by hot fluid flow controlled by brittle-ductile reactivation of BIF-basalt margins and crosscutting D1 faults. The Ni-Co-rich content of dolomite and a shift in REE ratios in carbonate-altered BIF towards Archean mafic rock signature (Y/Ho to 31 to 40, Sm/Yb to 1 to 2 and Gd/Gd* to 1.2 to 1.4) suggest that high-Mg basalts in the Windarling Range were the primary source of introduced metals. During ore stage 2, a syn-deformational and likely acidic and oxidised fluid flow along BIF-basalt margins and within D1 faults leached carbonate and precipitated lepidoblastic and anhedral/granoblastic hematite. High-grade magnetite-hematite ore is formed during this stage. Ore stage 3 hydrothermal specular hematite (spcH)-Fe-dolomite-quartz alteration was controlled by a late-orogenic, brittle, compressional/transpressional stage (D4; the regional-scale shear-zone-related D3 is not preserved in Windarling). This minor event remobilised iron oxides

  6. Efecto del Hierro en el Desarrollo de las Raíces de las Plantas

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    Correa Velásquez Jairo

    1964-08-01

    Full Text Available Se investigó el efecto del hierro en el desarrollo de las raíces del cacao, el café y el fríjol. También se observó la velocidad de recuperación de la clorofila en plantas cloróticas de cacao y café, al agregarles cantidades crecientes de hierro, y el efecto de dicha recuperación sobre el desarrollo radical. Además, se estudió el grado de absorción y movilización de Fe50 en plantas de cacao, y el efecto de distintas dosis de hierro en el crecimiento de raíces aisladas cacao, café y fríjol. Las plantas fueron cultivadas en el invernadero en solución HoagIand N° 2 sin Fe y las raíces para cultivo se obtuvieron de semillas germinadas en el laboratorio. Se usaron plantas de cacao del clon uf 668 de 3 meses y de café (variedad caturra con la misma edad. El hierro radiactivo utilizado fue en forma de cloruro (Fe59 cl 3 y el agregado a la solución o al follaje, en forma de quelato (Fe E. D. T. A.. Las adiciones de este elemento se hicieron cuando las plantas mostraban síntomas característicos de su deficiencia. Hubo una recuperación casi total de la clorosis y tanto el volumen como la longitud radical aumentaron con las aplicaciones crecientes de hierro, aunque la longitud relativa de los tallos mostró una tendencia decreciente. En las hojas de cacao se presentó una acumulación del Fe y su movilización hacia los demás órganos de la planta fue lenta y en proporción reducida en relación con el total absorbido. Igual cosa sucedió con el Fe50 suministrado a las raíces. No se pudieron observar los efectos del Fe en el crecimiento de raíces aisladas de cacao, café y fríjol, pues el desarrollo fue muy reducido, debido a que la rápida oxidación de los tejidos (al separar aquéllas del resto de la planta redujo la viabilidad a unos pocos días.

  7. From 3D to 4D seismic tomography at El Hierro Island (Canary Islands, Spain)

    Science.gov (United States)

    Garcia-Yeguas, A.; Koulakov, I.; Jakovlev, A.; Ibáñez, J. M.

    2012-04-01

    In this work we are going to show the advantages of a dynamic tomography 4D, versus a static image 3D related with a volcanic reactivation and eruption at El Hierro island (Canary Islands, Spain). In this process a high number of earthquakes before and during the eruptive processes have been registered. We are going to show a 3D image as an average of the velocity structure and then the characteristics and physical properties on the medium, including the presence or not of magma. This image will be complemented with its evolution along the time, observing its volcanic dynamic and its influence over the medium properties, including its power as an important element on early warnings protocols. After more than forty years of quiet at Canary Islands, since 1971 with Teneguía eruption at La Palma Island, and more than 200 years on El Hierro Island (The last eruption known at El Hierro took place in 1793, volcán de Lomo Negro), on 19th July on 2011 the Spanish seismic national network, administered by IGN (Instituto Geográfico Nacional), detected an increase of local seismic activity below El Hierro island (Canary Islands, Spain). Since this moment an intense swarm took place, with more than 11000 events, until 11th December, with magnitudes (MLg) from 0.2 to 4.4. In this period two eruptive processes have been declared in front of the South coast of El Hierro island, and they have not finished yet. This seismic swarm has allowed carrying out a 3D seismic tomography, using P and S waves traveltimes. It has showed a low velocity from the North to the South. On the other hand, we have performed a 4D seismic tomography, taking the events occurred at different intervals of time. We can observe the evolution of the negative anomaly along the time, from the North to the South, where has taken place La Restinga submarine eruption. 4D seismic tomography is an innovative and powerful tool able to show the evolution in time of a volcanic process.

  8. Psychological aspects in a volcanic crisis: El Hierro Island eruption (October, 2011).

    Science.gov (United States)

    Lopez, P.; Llinares, A.; Garcia, A.; Marrero, J. M.; Ortiz, R.

    2012-04-01

    The recent eruption on the El Hierro Island (Canary Islands, Spain) has shown that Psychology plays an important role in the emergence management of a natural phenomenon. However, Psychology continues to have no social coverage it deserves in the mitigation of the effects before, during and after the occurrence of a natural phenomenon. Keep in mind that an unresolved psychological problem involves an individual and collective mismatch may become unrecoverable. The population of El Hierro has been under a state of alert since July 2011, when seismic activity begins, until the occurrence of submarine eruption in October 2011 that is held for more than three months. During this period the inhabitants of the small island have gone through different emotional states ranging from confusion to disappointment. A volcanic eruption occurs not unexpectedly, allowing to have a time of preparation / action before the disaster. From the psychological point of view people from El Hierro Island have responded to different stages of the same natural process. Although the island of El Hierro is of volcanic origin, the population has no historical memory since the last eruption occurred in 1793. Therefore, the educational system does not adequately address the formation in volcanic risk. As a result people feel embarrassment when the seismovolcanic crisis begins, although no earthquakes felt. As an intermediate stage, when the earthquakes are felt by the population, scientists and operational Emergency Plan care to inform and prepare actions in case of a possible eruption. The population feel safe despite the concerns expressed by not knowing where, how and when the eruption will occur. Once started the submarine eruption, taking into account that all the actions (evacuation, relocation, etc.) have worked well and that both their basic needs and security are covered there are new states of mind. These new emotional states ranging from disenchantment with the phenomenology of the

  9. Volcanic Alert System (VAS) developed during the (2011-2013) El Hierro (Canary Islands) volcanic process

    Science.gov (United States)

    Ortiz, Ramon; Berrocoso, Manuel; Marrero, Jose Manuel; Fernandez-Ros, Alberto; Prates, Gonçalo; De la Cruz-Reyna, Servando; Garcia, Alicia

    2014-05-01

    In volcanic areas with long repose periods (as El Hierro), recently installed monitoring networks offer no instrumental record of past eruptions nor experience in handling a volcanic crisis. Both conditions, uncertainty and inexperience, contribute to make the communication of hazard more difficult. In fact, in the initial phases of the unrest at El Hierro, the perception of volcanic risk was somewhat distorted, as even relatively low volcanic hazards caused a high political impact. The need of a Volcanic Alert System became then evident. In general, the Volcanic Alert System is comprised of the monitoring network, the software tools for the analysis of the observables, the management of the Volcanic Activity Level, and the assessment of the threat. The Volcanic Alert System presented here places special emphasis on phenomena associated to moderate eruptions, as well as on volcano-tectonic earthquakes and landslides, which in some cases, as in El Hierro, may be more destructive than an eruption itself. As part of the Volcanic Alert System, we introduce here the Volcanic Activity Level which continuously applies a routine analysis of monitoring data (particularly seismic and deformation data) to detect data trend changes or monitoring network failures. The data trend changes are quantified according to the Failure Forecast Method (FFM). When data changes and/or malfunctions are detected, by an automated watchdog, warnings are automatically issued to the Monitoring Scientific Team. Changes in the data patterns are then translated by the Monitoring Scientific Team into a simple Volcanic Activity Level, that is easy to use and understand by the scientists and technicians in charge for the technical management of the unrest. The main feature of the Volcanic Activity Level is its objectivity, as it does not depend on expert opinions, which are left to the Scientific Committee, and its capabilities for early detection of precursors. As a consequence of the El Hierro

  10. Retificadores trifásicos com fator de potência unitário baseados nos transformadores trifásicos/bifásicos

    OpenAIRE

    Badin, Alceu André

    2009-01-01

    Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia Elétrica. Este trabalho apresenta o estudo dos retificadores de tensão trifásicos isolados em baixa freqüência, com fator de potência unitário e regulação das tensões de saída, baseados nos transformadores trifásicos/bifásicos. Trata-se de conversores que transferem energia de uma fonte CA trifásica para uma fonte CC, fazendo circular na fonte CA uma corrente senoidal de a...

  11. Recomendaciones para el diagnóstico y manejo de la anemia por déficit de hierro en la mujer embarazada

    Directory of Open Access Journals (Sweden)

    Daniel Ernst

    2017-05-01

    Full Text Available La anemia es una condición altamente prevalente a nivel mundial y, el déficit de hierro, la causa más frecuente, sin excepción; la mujer embarazada está particularmente en riesgo dada la mayor demanda de hierro que la gestación significa. La anemia se asocia a mayor morbilidad y mortalidad materno-perinatal. En mujeres embarazadas sin anemia, la prevención, mediante el uso de multivitamínicos que contienen hierro en dosis de 30-60 mg de hierro elemental, ha demostrado ser efectiva y se recomienda durante todo el embarazo. En casos de anemia, el diagnóstico de déficit de hierro se establece cuando la ferritina es menor a 30 ug/L y/o la saturación de transferrina es menor a 20%. La severidad de la anemia y la situación temporal en el embarazo, son factores modificantes del tratamiento. En mujeres embarazadas, con hemoglobina ≥9.0 g/dL y que tengan <34 semanas de embarazo, la indicación es tratamiento con hierro oral, en dosis de 100 mg al día, en días alternos, hasta normalizar los parámetros antes mencionados. Si la hemoglobina es <9.0 g/dL, o el embarazo es ≥34 semanas, el uso de hierro intravenoso ha demostrado ser más efectivo en corregir la anemia y el déficit de hierro y en disminuir la morbilidad materno-perinatal. En estos casos, sugerimos el uso del hierro carboximaltosa, dado su perfil de seguridad y efectividad favorable. Recomendamos conocer y practicar estas recomendaciones para el diagnóstico y manejo de la anemia por déficit de hierro durante el embarazo.

  12. Origin and significance of the 2011 El Hierro xeno-pumice

    Science.gov (United States)

    Zaczek-Pedroza, Kirsten; Troll, Valentin R.; Deegan, Frances M.; Meade, Fiona C.; Burchardt, Steffi; Carracedo, Juan C.; Klügel, Andreas; Harris, Chris; Wiesmaier, Sebastian; Berg, Sylvia E.; Barker, Abigail K.

    2014-05-01

    During the first week of the 2011/2012 submarine eruption off El Hierro (Canary Islands), peculiar light-coloured pumiceous rocks (xeno-pumice) were found floating on the sea. The appearance of these rocks led to a potentially inappropriate response from the authorities, because the rocks were viewed as likely indicators of high-silica magma and possible explosive eruptive behaviour. However, the eruption remained a relatively minor and dominantly effusive event and the origin and significance of these peculiar xeno-pumice rocks for volcanic monitoring remains unresolved. Three contrasting models have been put forward, describing them as: a) recycled hydrothermally altered felsic magmatic rocks (Meletlidis et al., 2012, Geophys. Res. Lett., 39:L17302), b) sediment-contaminated high-silica magma (Sigmarsson et al., 2013, Contrib. Mineral. Petrol., 165:601-622) or c) frothy xenoliths from pre-island sedimentary strata that were melted while immersed in magma (Troll et al., 2012, Solid Earth, 3:97-110). Here, we combine the three available datasets to assess the origin of El Hierro xeno-pumice in the light of texture, mineralogy, major and trace element composition, and oxygen isotope characteristics in order to discuss their significance. We note that: 1) Sedimentary relicts occur frequently in xeno-pumice samples with occasionally observed relict bedding. 2) Vesicle sizes are extremely variable, which documents multiple degassing events. The vesicles are biggest especially close to sedimentary relicts, likely the result of a complex mix of minerals and porewaters originally present. 3) The mineral assemblage of xeno-pumice includes quartz, smectite, illite, wollastonite, jasper and mica (XRD) and is akin to marine sedimentary rocks in the region (Hoernle, 1998, J. Petrol.,39:859-880; Robertson & Stillman, 1979, J. Geol. Soc., 136:47 -60; Aparicio et al., 2006, Geol. Mag. 143:181 -193). 4) CIPW norms calculated from xeno-pumice major element compositions show the

  13. Precursory diffuse CO2 emission signature of the 2011 El Hierro submarine eruption, Canary Islands

    Science.gov (United States)

    Pérez, N. M.; Padilla, G. D.; Padrón, E.; Hernández, P. A.; Melián, G. V.; Barrancos, J.; Dionis, S.; Rodríguez, F.; Nolasco, D.; Calvo, D.; Hernández, I.; Peraza, M. D.

    2012-04-01

    El Hierro is the youngest and southernmost island of the Canarian archipelago and represents the summit of a volcanic shield elevating from the surrounding seafloor at depth of 4000 m to up to 1501 m above sea level. The island is believed to be near the present hotspot location in the Canaries with the oldest subaerial rocks dated at 1.12 Ma. The subaerial parts of the El Hierro rift zones (NE, NW and S Ridges) are characterized by tightly aligned dyke complexes with clusters of cinder cones as their surface expressions. Since 16 July, an anomalous seismicity at El Hierro Island was recorded by IGN seismic network. Volcanic tremor started at 05:15 on 10 October, followed on the afternoon of 12 October by a green discolouration of seawater, strong bubbling and degassing, and abundant bombs on a decimetre scale found floating on the ocean surface offshore, southwest of La Restinga village, indicating the occurrence of a submarine volcanic eruption at approximately 2 km far the coast line of La Restinga. Further episodes have occurred during November, December 2011 and January 2012, with turbulent water, foam rings, and volcanic material again reaching the sea surface. In order to improve the volcanic surveillance program of El Hierro Island and to provide a multidisciplinary approach, a continuous geochemical station to measure CO2 efflux was installed on September 2003 in Llanos de Guillen, the interception center of the three volcanic-rift zones of the island, with the aim of detecting changes in the diffuse emission of CO2 related to the seismic or volcanic activity. The station measures on an hourly basis the CO2 and H2S efflux, the CO2 and H2S air concentrations, the soil water content and temperature and the atmospheric parameters: wind speed and direction, air temperature and humidity and barometric pressure. The meteorological parameters together with the air CO2 concentration are measured 1 m above the ground and the soil water content and soil temperature

  14. Nuevos conocimientos sobre el metabolismo del hierro New knowledge of iron metabolism

    Directory of Open Access Journals (Sweden)

    Mariela Forrellat Barrios

    2005-12-01

    Full Text Available El hierro es un mineral de elevada importancia para el organismo y su regulación requiere de una red molecular compleja. Hasta hace unos años solo se conocían 3 proteínas que intervenían en el metabolismo del hierro, pero en la última década, se han descubierto de forma secuencial, y a partir del estudio de algunas enfermedades genéticas como la hemocromatosis hereditaria, nuevas proteínas que participan en la homeostasia del hierro y que están implicadas en su transporte, absorción, reciclaje y balance en el organismo. La identificación y aislamiento de estas proteínas lleva inevitablemente a la modificación de los modelos clásicos de regulación de la homeostasia de este importante mineral. En este trabajo se realizó una revisión de los elementos esenciales conocidos hasta la actualidad de cada una de estas nuevas proteínas y la interacción entre ellasIron is a very important mineral for the organism and its regulation requires a complex molecular network. Only 3 proteins that took part in iron metabolism were known a few years ago, but in the last decade, new proteins that participate in iron homeostasis and that are involved in its transportation, absorption, recycling and balance in the organism have been discovered in a sequential way, starting from the study of some genetical diseases, such as hereditary hemochromatosis. The identification and isolation of these proteins lead inevitably to the modification of the classical models of regulation of the homeostasis of this powerful mineral. A review of the esential elements known up to now of each of these new proteins and the interaction among them was made in this paper

  15. Dissolved gas geochemical signatures of the ground waters related to the 2011 El Hierro magmatic reactivation

    Science.gov (United States)

    Rodríguez, F.; Hernández, P. A.; Padrón, E.; Pérez, N. M.; Sumino, H.; Melián, G. V.; Padilla, G. D.; Barrancos, J.; Dionis, S.; Nolasco, D.; Calvo, D.; Hernández, I.; Peraza, M. D.

    2012-04-01

    El Hierro Island is the south westernmost and the youngest island of the Canary archipelago (Restinga village (at the southernmost part of El Hierro island), suggesting the existence of a submarine eruption. Since October 12, frequent episodes of, turbulent gas emission and foaming, and the appearance of steamy lava fragments has been observed on the sea surface. Instituto Volcanologico de Canarias (INVOLCAN) started a hydrogeochemical program on August 2011 in order to evaluate the temporal evolution of dissolved gases on four different observation points (vertical and horizontal wells) of El Hierro. Three wells are located on the north of the island (where the seismic activity occurred at the beginning of the volcano-seismic unrest) and one horizontal well (gallery) in the south. At each observation point the concentration of dissolved helium, CO2, N2, O2 and Ar and the isotopic composition of He, C-CO2 and Ar have been measured three times per week. Significant increases on the dissolved gases content, mainly on CO2 and He/CO2 ratio, have been measured at all the observation points prior to the increasing of released seismic energy. Isotopic composition of dissolved helium, measured as 3He/4He ratio, showed an significant increase (from 1-3 RA up to 7.2 RA, being RA the isotopic 3He/4He ratio on air) at all the observation points 20 days before the occurrence of the submarine eruption and these relatively high 3He/4He values have been maintained along the volcanic unrest period. The isotopic composition of CO2 has showed also significant changes in relation to the release of seismic energy. The results observed on this dissolved gases study have been tremendously beneficial on the volcanic surveillance tools to study and forecast the evolution of the seismic-volcanic crisis.

  16. Actualidades de las características del hierro y su uso en pediatría

    Directory of Open Access Journals (Sweden)

    Tania Tostado-Madrid

    2015-05-01

    Full Text Available Se revisan diversos aspectos del hierro: datos epidemiológicos y fisiológicos recientes, factores que regulan su absorción y que aumentan o reducen su biodisponibilidad; se evalúa el contenido y porcentaje de biodisponibilidad del hierro de diferentes alimentos y productos a través de tablas comparativas. Se destaca la importancia y la razón de un adecuado suplemento y la elección apropiada de fuentes alimentarias.

  17. La anemia por deficiencia de hierro en la población infantil de Cuba. Brechas por cerrar

    OpenAIRE

    Pita-Rodríguez, Gisela; Jiménez-Acosta, Santa

    2011-01-01

    La anemia es un problema de salud mundial que afecta tanto a los países desarrollados como a aquellos en desarrollo. Sus causas pueden ser multifactoriales y frecuentemente pueden coexisitir varias de ellas; la principal es la baja ingestión de alimentos con fuentes adecuadas de hierro, tanto en cantidad como en calidad. En Cuba se está trabajando desde el año 1987 en el desarrollo de programas de intervención para la prevención de la anemia por deficiencia de hierro en la población, pero a p...

  18. Estado nutricional del hierro en niños de comunidades indígenas de Cali, Colombia

    OpenAIRE

    Bolaños-Gallardo, María Victoria; Flórez Echeverry, Ofelia; Bermúdez Escobar, Amparo; Hernández Sampayo, Luzmila; Salcedo-Cifuentes, Mercedes

    2014-01-01

    Introducción: Los escolares son susceptibles a padecer anemia y deficiencia de micronutrientes. No hay reportes del estado del hierro en indígenas del sector urbano. Objetivo: Establecer el estado del hierro en niños de 5 a 14 años de edad de seis comunidades indígenas residentes en la ciudad de Cali-Colombia. Sujetos y métodos: Se estudiaron 62 niños indígenas de 5 a 14 años de edad, sin antecedentes febriles. Se les midió hemoglobina, hematocrito, volumen corpuscular medio, ferritina y tran...

  19. Soil gas radon and volcanic activity at El Hierro (Canary Islands) before and after the 2011-2012 submarine eruption

    Science.gov (United States)

    Barrancos, J.; Padilla, G.; Hernandez Perez, P. A.; Padron, E.; Perez, N.; Melian Rodriguez, G.; Nolasco, D.; Dionis, S.; Rodriguez, F.; Calvo, D.; Hernandez, I.

    2012-12-01

    El Hierro is the youngest and southernmost island of the Canarian archipelago and represents the summit of a volcanic shield elevating from the surrounding seafloor at depth of 4000 m to up to 1501 m above sea level. The island is believed to be near the present hotspot location in the Canaries with the oldest subaerial rocks dated at 1.12 Ma. The subaerial parts of the El Hierro rift zones (NE, NW and S Ridges) are characterized by tightly aligned dyke complexes with clusters of cinder cones as their surface expressions. Since July 16, 2011, an anomalous seismicity at El Hierro Island was recorded by IGN seismic network. Volcanic tremor started at 05:15 hours on October 10, followed on the afternoon of October 12 by a green discolouration of seawater, strong bubbling and degassing indicating the initial stage of submarine volcanic eruption at approximately 2 km off the coast of La Restinga, El Hierro. Soil gas 222Rn and 220Rn activities were continuously measured during the period of the recent volcanic unrest occurred at El Hierro, at two different geochemical stations, HIE02 and HIE03. Significant increases in soil 222Rn activity and 222Rn/220Rn ratio from the soil were observed at both stations prior the submarine eruption off the coast of El Hierro, showing the highest increases before the eruption onset and the occurrence of the strongest seismic event (M=4.6). A statistical analysis showed that the long-term trend of the filtered data corresponded closely to the seismic energy released during the volcanic unrest. The observed increases of 222Rn are related to the rock fracturing processes (seismic activity) and the magmatic CO2 outflow increase, as observed in HIE03 station. Under these results, we find that continuous soil radon studies are important for evaluating the volcanic activity of El Hierro and they demonstrate the potential of applying continuous monitoring of soil radon to improve and optimize the detection of early warning signals of future

  20. Efecto de la estacionalidad sobre el estado nutricional de Hierro, Zinc y Cobre

    OpenAIRE

    Miranda D, Melissa; Olivares G, Manuel; Araya Q, Magdalena; Pizarro A, Fernando

    2013-01-01

    El consumo de alimentos y por lo tanto el estado de nutrición de los micronutrientes está condicionado por diferentes factores como la estacionalidad. El presente estudio tuvo como objetivo determinar el efecto de la estacionalidad sobre el estado nutricional de hierro, zinc y cobre de sujetos adultos habitantes de la ciudad de Santiago de Chile. Un estudio longitudinal en 50 sujetos de ambos sexos se realizó entre los meses de septiembre del 2005 y agosto del 2006. Durante la primera semana ...

  1. Physico-chemical changes of the ground waters related to the 2011 El Hierro magmatic reactivation

    Science.gov (United States)

    Dionis, S.; Melián, G.; Padrón, E.; Padilla, G.; Nolasco, D.; Rodríguez, F.; Hernández, I.; Peraza, D.; Barrancos, J.; Hernández, P.; Calvo, D.; Pérez, N.

    2012-04-01

    The island of El Hierro (278 Km2), is the smallest, the southwesternmost and the youngest island (˜1.12 My) of the Canarian archipelago. The main geological characteristics of El Hierro consist on the presence of three convergent ridges of volcanic cones on a truncated trihedron shape and giant landslides between the three rift zones, being the most recent El Golfo on the northwest flank of the island. On July 2011 an anomalous seismic activity at Hierro Island started and suggested the initial stage of a volcanic unrest in the volcanic system. On October 10, after the occurrence of more than 10,000 earthquakes, a submarine eruption started. Evidences of this submarine volcanic eruption were visible on the sea surface to the south of La Restinga village, at the south of the island, in the form of large light-green coloured area, turbulent gas emission and the appearance of steamy volcanic fragments three days later. As part of its volcanic surveillance activities, the Instituto Volcanologico de Canarias (INVOLCAN) started a hydrogeochemical monitoring program on August 2011 in order to evaluate the temporal evolution of several physico-chemical parameters of the ground water system of El Hierro. Four observation sites were selected: three wells on the north of the island, where the seismic activity was located at the beginning of the volcano-seismic unrest (SIMO, FRON and PADO) and one horizontal well (gallery) in the south (TACO). Ground water sampling is being regularly collected, three times per week, at each observation site, and in-situ measurements of pH, conductivity and temperature measurements are performed. After 6 month of monitoring, no significant changes have been observed on pH and temperature measurements from all the observation sites. However, clear sharp decrease of conductivity was observed at SIMO on October 10 when the seismic tremor started. In addition, the strongest conductivity decrease pattern was observed later on at SIMO and PADO on

  2. El Hierro's floating stones as messengers of crust-magma interaction at depth

    Science.gov (United States)

    Burchardt, S.; Troll, V. R.; Schmeling, H.; Koyi, H.; Blythe, L. S.; Longpré, M. A.; Deegan, F. M.

    2012-04-01

    During the early stages of the submarine eruption that started on October 10 2011 south of El Hierro, Canary Islands, Spain, peculiar eruption products were found floating on the sea surface. These centimetre- to decimetre-sized "bombs" have been termed "restingolites" after the nearby village La Restinga and consist of a basaltic rind and a white to light grey core that resembles pumice in texture. According to Troll et al. (2011; see also Troll et al. EGU 2012 Abstracts), this material consists of a glassy matrix hosting extensive vesicle networks, which results in extremely low densities allowing these rocks to float on sea water. Mineralogical and geochemical analyses reveal that the "restingolites" originate from the sedimentary rocks (sand-, silt-, and mudstones) that form layer 1 of the oceanic crust beneath El Hierro. During the onset and early stages of the eruption, magma ponded at the base of this sedimentary sequence, breaking its way through the sedimentary rocks to the ocean floor. The textures of the "restingolites" reveal that crust-magma interaction during fragmentation and transport of the xenoliths involved rapid partial melting and volatile exsolution. Xenoliths strikingly similar to those from El Hierro are known from eruptions on other Canary Islands (e.g. La Palma, Gran Canaria, and Lanzarote). In fact, they resemble in texture xenoliths of various protoliths from volcanic areas worldwide (e.g. Krakatao, Indonesia, Cerro Quemado, Guatemala, Laacher See, Germany). This indicates that the process of partial melting and volatile exsolution, which the "restingolites" bear witness of, is probably occurring frequently during shallow crustal magma emplacement. Thermomechanical numerical models of the effect of the density decrease associated with the formation of vesicle networks in partially molten xenoliths show that xenoliths of crustal rocks initially sink in a magma chamber, but may start to float to the chamber roof once they start to heat up

  3. Perdida de carga en conductos de hierro galvanizado conduciendo agua residual de instalaciones de gallinas ponedoras

    OpenAIRE

    RODRIGUES DE SOUZA, José ANTONIO; ASTONI MOREIRA, DÉBORA; OLIVEIRA BATISTA, RAFAEL; OSORIO S., JAIRO ALEXANDER; ZAPATA MARÍN, OLGA LUCÍA

    2011-01-01

    Las operaciones relacionadas con la producción de aves de corral pueden generar efluentes procedentes de fuentes distintas, incluida la escorrentía originada en las jaulas, alimentación y abastecimiento de agua de las aves y de las instalaciones de almacenamiento y manejo de residuos. En todo proyecto de explotación de aves de corral, se debe tener en cuenta el manejo de residuos y aguas residuales, las cuales pueden ser conducidas en tuberías de hierro galvanizado. El objetivo de este trabaj...

  4. Provenance and tectonic setting of siliciclastic rocks associated with the Neoproterozoic Dahongliutan BIF: Implications for the Precambrian crustal evolution of the Western Kunlun orogenic belt, NW China

    Science.gov (United States)

    Hu, Jun; Wang, He; Wang, Min

    2017-10-01

    The Late Neoproterozoic Dahongliutan BIF is associated with siliciclastic rocks in the Tianshuihai terrane of the Western Kunlun orogenic belt (WKO), NW China. The sedimentary rocks have various weathering indices (e.g., CIA = 57-87, PIA = 61-96 and Th/U = 4.85-12.45), indicative of varying degrees of weathering in the source area. The rocks have trace element ratios, such as Th/Sc = 0.60-1.21 and Co/Th = 0.29-1.67, and light rare earth element (LREE) enriched chondrite-normalized REE patterns, suggesting that they were mainly sourced from intermediate and felsic rocks. Available U-Pb ages of detrital zircon from these rocks reveal that the detrital sources may have been igneous and metamorphic rocks from the WKO and the Tarim Block. Our study suggests that the Dahongliutan BIF and hosting siliciclastic rocks may have deposited in a setting transitional from a passive to active continental margin, probably related to the Late Neoproterozoic-Early Cambrian seafloor spreading and subduction of the Proto-Tethys Ocean. U-Pb dating of 163 detrital zircons defines five major age populations at 2561-2329 Ma, 2076-1644 Ma, 1164-899 Ma, 869-722 Ma and 696-593 Ma. These age groups broadly correspond to the major stages of supercontinent assembly and breakup events widely accepted for Columbia, Rodinia and Gondwana. Some zircons have TDM2 model ages of 3.9-1.8 Ga and negative εHf(t) values, suggesting that the Archean to Paleoproterozoic (as old as Eoarchean) crustal materials were episodically reworked and incorporated into the late magmatic process in the WKO. Some Neoproterozoic zircons have TDM2 model ages of 1.47-1.07 Ga and 1.81-1.53 Ga and positive εHf(t) values, indicating juvenile crustal growth during the Mesoproterozoic. Our new results, combined with published data, imply that both the Tianshuihai terrane in the WKO and the Tarim Block share the same Precambrian tectonic evolution history.

  5. Nannofossils in 2011 El Hierro eruptive products reinstate plume model for Canary Islands

    Science.gov (United States)

    Zaczek, Kirsten; Troll, Valentin R.; Cachao, Mario; Ferreira, Jorge; Deegan, Frances M.; Carracedo, Juan Carlos; Soler, Vicente; Meade, Fiona C.; Burchardt, Steffi

    2015-01-01

    The origin and life cycle of ocean islands have been debated since the early days of Geology. In the case of the Canary archipelago, its proximity to the Atlas orogen led to initial fracture-controlled models for island genesis, while later workers cited a Miocene-Quaternary east-west age-progression to support an underlying mantle-plume. The recent discovery of submarine Cretaceous volcanic rocks near the westernmost island of El Hierro now questions this systematic age-progression within the archipelago. If a mantle-plume is indeed responsible for the Canaries, the onshore volcanic age-progression should be complemented by progressively younger pre-island sedimentary strata towards the west, however, direct age constraints for the westernmost pre-island sediments are lacking. Here we report on new age data obtained from calcareous nannofossils in sedimentary xenoliths erupted during the 2011 El Hierro events, which date the sub-island sedimentary rocks to between late Cretaceous and Pliocene in age. This age-range includes substantially younger pre-volcanic sedimentary rocks than the Jurassic to Miocene strata known from the older eastern islands and now reinstate the mantle-plume hypothesis as the most plausible explanation for Canary volcanism. The recently discovered Cretaceous submarine volcanic rocks in the region are, in turn, part of an older, fracture-related tectonic episode.

  6. Cyclic thermal behavior associated to the degassing process at El Hierro submarine volcano, Canary Islands.

    Science.gov (United States)

    Fraile-Nuez, E.; Santana-Casiano, J. M.; González-Dávila, M.

    2016-12-01

    One year after the ceasing of magmatic activity in the shallow submarine volcano of the island of El Hierro, significant physical-chemical anomalies produced by the degassing process as: (i) thermal anomalies increase of +0.44 °C, (ii) pH decrease of -0.034 units, (iii) total dissolved inorganic carbon, CT increase by +43.5 µmol kg-1 and (iv) total alkalinity, AT by +12.81 µmol kg-1 were still present in the area. These evidences highlight the potential role of the shallow degassing processes as a natural ecosystem-scale experiments for the study of significant effects of global change stressors on marine environments. Additionally, thermal time series obtained from a temporal yo-yo CTD study, in isopycnal components, over one of the most active points of the submarine volcano have been analyzed in order to investigate the behavior of the system. Signal processing of the thermal time series highlights a strong cyclic temperature period of 125-150 min at 99.9% confidence, due to characteristic time-scales revealed in the periodogram. These long cycles might reflect dynamics occurring within the shallow magma supply system below the island of El Hierro.

  7. Environmental monitoring of El Hierro Island submarine volcano, by combining low and high resolution satellite imagery

    Science.gov (United States)

    Eugenio, F.; Martin, J.; Marcello, J.; Fraile-Nuez, E.

    2014-06-01

    El Hierro Island, located at the Canary Islands Archipelago in the Atlantic coast of North Africa, has been rocked by thousands of tremors and earthquakes since July 2011. Finally, an underwater volcanic eruption started 300 m below sea level on October 10, 2011. Since then, regular multidisciplinary monitoring has been carried out in order to quantify the environmental impacts caused by the submarine eruption. Thanks to this natural tracer release, multisensorial satellite imagery obtained from MODIS and MERIS sensors have been processed to monitor the volcano activity and to provide information on the concentration of biological, chemical and physical marine parameters. Specifically, low resolution satellite estimations of optimal diffuse attenuation coefficient (Kd) and chlorophyll-a (Chl-a) concentration under these abnormal conditions have been assessed. These remote sensing data have played a fundamental role during field campaigns guiding the oceanographic vessel to the appropriate sampling areas. In addition, to analyze El Hierro submarine volcano area, WorldView-2 high resolution satellite spectral bands were atmospherically and deglinted processed prior to obtain a high-resolution optimal diffuse attenuation coefficient model. This novel algorithm was developed using a matchup data set with MERIS and MODIS data, in situ transmittances measurements and a seawater radiative transfer model. Multisensor and multitemporal imagery processed from satellite remote sensing sensors have demonstrated to be a powerful tool for monitoring the submarine volcanic activities, such as discolored seawater, floating material and volcanic plume, having shown the capabilities to improve the understanding of submarine volcanic processes.

  8. Driving magma to the surface: The 2011-2012 El Hierro Volcanic Eruption

    Science.gov (United States)

    López, Carmen; Benito-Saz, Maria A.; Martí, Joan; del-Fresno, Carmen; García-Cañada, Laura; Albert, Helena; Lamolda, Héctor

    2017-08-01

    We reanalyzed the seismic and deformation data corresponding to the preeruptive unrest on El Hierro (Canary Islands) in 2011. We considered new information about the internal structure of the island. We updated the seismic catalog to estimate the full evolution of the released seismic energy and demonstrate the importance of nonlocated earthquakes. Using seismic data and GPS displacements, we characterized the shear-tensile type of the predominant fracturing and modeled the strain and stress fields for different time periods. This enabled us to identify a prolonged first phase characterized by hydraulic tensile fracturing, which we interpret as being related to the emplacement of new magma below the volcanic edifice on El Hierro. This was followed by postinjection unidirectional migration, probably controlled by the stress field and the distribution of the structural discontinuities. We identified the effects of energetic magmatic pulses occurring a few days before the eruption that induced shear seismicity on preexisting faults within the volcano and raised the Coulomb stress over the whole crust. We suggest that these magmatic pulses reflect the crossing of the Moho discontinuity, as well as changes in the path geometry of the dyke migration toward the surface. The final phase involved magma ascent through a prefractured crust.

  9. Volcanic alert system (VAS) developed during the 2011-2014 El Hierro (Canary Islands) volcanic process

    Science.gov (United States)

    García, Alicia; Berrocoso, Manuel; Marrero, José M.; Fernández-Ros, Alberto; Prates, Gonçalo; De la Cruz-Reyna, Servando; Ortiz, Ramón

    2014-06-01

    The 2011 volcanic unrest at El Hierro Island illustrated the need for a Volcanic Alert System (VAS) specifically designed for the management of volcanic crises developing after long repose periods. The VAS comprises the monitoring network, the software tools for analysis of the monitoring parameters, the Volcanic Activity Level (VAL) management, and the assessment of hazard. The VAS presented here focuses on phenomena related to moderate eruptions, and on potentially destructive volcano-tectonic earthquakes and landslides. We introduce a set of new data analysis tools, aimed to detect data trend changes, as well as spurious signals related to instrumental failure. When data-trend changes and/or malfunctions are detected, a watchdog is triggered, issuing a watch-out warning (WOW) to the Monitoring Scientific Team (MST). The changes in data patterns are then translated by the MST into a VAL that is easy to use and understand by scientists, technicians, and decision-makers. Although the VAS was designed specifically for the unrest episodes at El Hierro, the methodologies may prove useful at other volcanic systems.

  10. Heterogeneous vesiculation of 2011 El Hierro xeno-pumice revealed by X-ray computed microtomography

    Science.gov (United States)

    Berg, S. E.; Troll, V. R.; Deegan, F. M.; Burchardt, S.; Krumbholz, M.; Mancini, L.; Polacci, M.; Carracedo, J. C.; Soler, V.; Arzilli, F.; Brun, F.

    2016-12-01

    During the first week of the 2011 El Hierro submarine eruption, abundant light-coloured pumiceous, high-silica volcanic bombs coated in dark basanite were found floating on the sea. The composition of the light-coloured frothy material (`xeno-pumice') is akin to that of sedimentary rocks from the region, but the textures resemble felsic magmatic pumice, leaving their exact mode of formation unclear. To help decipher their origin, we investigated representative El Hierro xeno-pumice samples using X-ray computed microtomography for their internal vesicle shapes, volumes, and bulk porosity, as well as for the spatial arrangement and size distributions of vesicles in three dimensions (3D). We find a wide range of vesicle morphologies, which are especially variable around small fragments of rock contained in the xeno-pumice samples. Notably, these rock fragments are almost exclusively of sedimentary origin, and we therefore interpret them as relicts an the original sedimentary ocean crust protolith(s). The irregular vesiculation textures observed probably resulted from pulsatory release of volatiles from multiple sources during xeno-pumice formation, most likely by successive release of pore water and mineral water during incremental heating and decompression of the sedimentary protoliths.

  11. Palaeomagnetic constraints on the age of Lomo Negro volcanic eruption (El Hierro, Canary Islands)

    Science.gov (United States)

    Villasante-Marcos, Víctor; Pavón-Carrasco, Francisco Javier

    2014-12-01

    A palaeomagnetic study has been carried out in 29 cores drilled at six different sites from the volcanic products of Lomo Negro eruption (El Hierro, Canary Islands, Spain). Systematic thermal and alternating field demagnetization of the samples' natural remanent magnetization revealed a northward, stable palaeomagnetic direction similar in all the samples. Rock magnetic experiments indicate that this palaeomagnetic component is carried by a mixture of high-Ti and low-Ti titanomagnetite crystals typical of basaltic lithologies that have experienced a significant degree of oxyexsolution during subaerial cooling. The well constrained palaeomagnetic direction of Lomo Negro lavas was used to perform a palaeomagnetic dating of the volcanic event, using the SHA.DIF.14k global geomagnetic model restricted for the last 3000 yr. It can be unambiguously concluded that Lomo Negro eruption occurred well before the previously proposed date of 1793 AD, with three different age ranges being statistically possible during the last 3 ka: 115 BC-7 AD, 410-626 AD and 1499-1602 AD. The calibration of a previously published non-calibrated 14C dating suggests a XVI c. date for Lomo Negro eruption. This conclusion leaves open the possibility that the seismic crisis occurred at El Hierro in 1793 AD was related to an intrusive magmatic event that either did not reach the surface or either culminated in an unregistered submarine eruption similar to the one occurred in 2011-2012 at the southern off-shore ridge of the island.

  12. Repeated magmatic intrusions at El Hierro Island following the 2011-2012 submarine eruption

    Science.gov (United States)

    Benito-Saz, Maria A.; Parks, Michelle M.; Sigmundsson, Freysteinn; Hooper, Andrew; García-Cañada, Laura

    2017-09-01

    After more than 200 years of quiescence, in July 2011 an intense seismic swarm was detected beneath the center of El Hierro Island (Canary Islands), culminating on 10 October 2011 in a submarine eruption, 2 km off the southern coast. Although the eruption officially ended on 5 March 2012, magmatic activity continued in the area. From June 2012 to March 2014, six earthquake swarms, indicative of magmatic intrusions, were detected underneath the island. We have studied these post-eruption intrusive events using GPS and InSAR techniques to characterize the ground surface deformation produced by each of these intrusions, and to determine the optimal source parameters (geometry, location, depth, volume change). Source inversions provide insight into the depth of the intrusions ( 11-16 km) and the volume change associated with each of them (between 0.02 and 0.13 km3). During this period, > 20 cm of uplift was detected in the central-western part of the island, corresponding to approximately 0.32-0.38 km3 of magma intruded beneath the volcano. We suggest that these intrusions result from deep magma migrating from the mantle, trapped at the mantle/lower crust discontinuity in the form of sill-like bodies. This study, using joint inversion of GPS and InSAR data in a post-eruption period, provides important insight into the characteristics of the magmatic plumbing system of El Hierro, an oceanic intraplate volcanic island.

  13. Significant discharge of CO2 from hydrothermalism associated with the submarine volcano of El Hierro Island

    Science.gov (United States)

    Santana-Casiano, J. M.; Fraile-Nuez, E.; González-Dávila, M.; Baker, E. T.; Resing, J. A.; Walker, S. L.

    2016-05-01

    The residual hydrothermalism associated with submarine volcanoes, following an eruption event, plays an important role in the supply of CO2 to the ocean. The emitted CO2 increases the acidity of seawater. The submarine volcano of El Hierro, in its degasification stage, provided an excellent opportunity to study the effect of volcanic CO2 on the seawater carbonate system, the global carbon flux, and local ocean acidification. A detailed survey of the volcanic edifice was carried out using seven CTD-pH-ORP tow-yo studies, localizing the redox and acidic changes, which were used to obtain surface maps of anomalies. In order to investigate the temporal variability of the system, two CTD-pH-ORP yo-yo studies were conducted that included discrete sampling for carbonate system parameters. Meridional tow-yos were used to calculate the amount of volcanic CO2 added to the water column for each surveyed section. The inputs of CO2 along multiple sections combined with measurements of oceanic currents produced an estimated volcanic CO2 flux = 6.0 105 ± 1.1 105 kg d-1 which is ~0.1% of global volcanic CO2 flux. Finally, the CO2 emitted by El Hierro increases the acidity above the volcano by ~20%.

  14. PERDIDA DE CARGA EN CONDUCTOS DE HIERRO GALVANIZADO CONDUCIENDO AGUA RESIDUAL DE INSTALACIONES DE GALLINAS PONEDORAS

    Directory of Open Access Journals (Sweden)

    JOSÉ ANTONIO RODRIGUES DE SOUZA

    2011-01-01

    Full Text Available Las operaciones relacionadas con la producción de aves de corral pueden generar efluentes procedentes de fuentes distintas, incluida la escorrentía originada en las jaulas, alimentación y abastecimiento de agua de las aves y de las instalaciones de almacenamiento y manejo de residuos. En todo proyecto de explotación de aves de corral, se debe tener en cuenta el manejo de residuos y aguas residuales, las cuales pueden ser conducidas en tuberías de hierro galvanizado. El objetivo de este trabajo, fue el ajustar ecuaciones para estimar la perdida de carga continua en conductos de hierro galvanizado en los diámetros comerciales, variando de 50 a 150 mm, operando con agua residual de gallinas ponedoras en diferentes concentraciones de sólidos totales. Los resultados indicaron que las metodologías de Duffy & Titchener y HazenWilliams modificadas presentaron ajustes cuyo coeficiente de determinación fue superior a 0,95, por lo que es considerado apropiado para el dimensionamiento de proyectos hidráulicos.

  15. Origin of three-armed rifts in volcanic islands: the case of El Hierro (Canary Islands)

    Science.gov (United States)

    Galindo Jiménez, Inés; Becerril Carretero, Laura; Martí Molist, Joan; Gudmundsson, Agust

    2015-04-01

    Rifts zones in volcanic oceanic islands are common structures that have been explained through several theories/models. However, despite all these models it is as yet unclear whether it is the intense intrusive activity or the sector collapses that actually control the structural evolution and geometry of oceanic-island rift zones. Here we provide a new hypothesis to explain the origin and characteristics of the feeding system of oceanic-island rift zones based on the analysis of more than 1700 surface, subsurface (water galleries), and submarine structural data from El Hierro (Canary Islands). El Hierro's geological structure is primarily controlled by a three-armed rift-zone, the arms striking NE, WSW and S. Between the rift axes there are three valleys formed during huge landslides: El Golfo, El Julan, and Las Playas. Our results show: (1) a predominant NE-SW strike of structural elements, which coincides with the main regional trend of the Canary Archipelago as a whole; (2) a clear radial strike distribution of structural elements for the whole volcanic edifice (including submarine flanks) with respect to the centre of the island; (3) that the rift zones are mainly subaerial structures and do not propagate through the submarine edifice; (4) that it is only in the NE rift that structures have a general strike similar to that of the rift as a whole, and; (5) that in the W and S rifts there is not clear main direction, showing the structural elements in the W rift a fan distribution coinciding with the general radial pattern in the island as a whole. Based on these data, we suggest that the radial-striking structures reflect comparatively uniform stress fields that operated during the constructive episodes, mainly conditioned by the combination of overburden pressure, gravitational spreading, and magma-induced stresses. By contrast, in the shallower parts of the edifice, that is, the NE-SW, N-S and WNW-ESE-striking structures, reflect local stress fields related

  16. Lithospheric magma dynamics beneath the El Hierro Volcano, Canary Islands: insights from fluid inclusions

    Science.gov (United States)

    Oglialoro, E.; Frezzotti, M. L.; Ferrando, S.; Tiraboschi, C.; Principe, C.; Groppelli, G.; Villa, I. M.

    2017-10-01

    At active volcanoes, petrological studies have been proven to be a reliable approach in defining the depth conditions of magma transport and storage in both the mantle and the crust. Based on fluid inclusion and mineral geothermobarometry in mantle xenoliths, we propose a model for the magma plumbing system of the Island of El Hierro (Canary Islands). The peridotites studied here were entrained in a lava flow exposed in the El Yulan Valley. These lavas are part of the rift volcanism that occurred on El Hierro at approximately 40-30 ka. The peridotites are spinel lherzolites, harzburgites, and dunites which equilibrated in the shallow mantle at pressures between 1.5 and 2 GPa and at temperatures between 800 and 950 °C (low-temperature peridotites; LT), as well as at higher equilibration temperatures of 900 to 1100 °C (high-temperature peridotites; HT). Microthermometry and Raman analyses of fluid inclusions reveal trapping of two distinct fluid phases: early type I metasomatic CO2-N2 fluids ( X N2 = 0.01-0.18; fluid density (d) = 1.19 g/cm3), coexisting with silicate-carbonate melts in LT peridotites, and late type II pure CO2 fluids in both LT (d = 1.11-1.00 and 0.75-0.65 g/cm3) and HT ( d = 1.04-1.11 and 0.75-0.65 g/cm3) peridotites. While type I fluids represent metasomatic phases in the deep oceanic lithosphere (at depths of 60-65 km) before the onset of magmatic activity, type II CO2 fluids testify to two fluid trapping episodes during the ascent of xenoliths in their host mafic magmas. Identification of magma accumulation zones through interpretation of type II CO2 fluid inclusions and mineral geothermobarometry indicate the presence of a vertically stacked system of interconnected small magma reservoirs in the shallow lithospheric mantle between a depth of 22 and 36 km (or 0.67 to 1 GPa). This magma accumulation region fed a short-lived magma storage region located in the lower oceanic crust at a depth of 10-12 km (or 0.26-0.34 GPa). Following our model

  17. El uso del hierro en la Casa Milá de Barcelona

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    Vila Rodríguez, Rafael

    1990-08-01

    Full Text Available The materials and construction systems, even the conception of the general structure, were for Gaudí no more than mediums at the service of the formal and spatial expression of his architectural imagination. Sometimes, the use of certain materials was indiscriminate or without sufficient guarantees. The Casa Milá is a good example. The use of laminated iron in the Pedrera, which allowed Gaudí to conceive a story independent of the façades —wall-screens of stone which seem to defy the law of gravity—, have been, at the same time, the main cause of the deterioration of these façades. In the case of the structure, the conceptual solution based on the use of iron has responded well to the static needs. This has not occured with the solutions —no less ingeneous but too improvlsed and risky— foreseen, also based on iron, to hold up the façade. Here, the material, subjected to the effects of humidity —favored by the form given to the stone—, has not resisted the passage of time very well.

    Los materiales y los sistemas constructivos, incluso la concepción de la estructura general, no eran para Gaudí más que medios al servicio de la expresividad formal y espacial de su imaginativa arquitectura. A veces, la utilización de algunos materiales se hizo de forma indiscriminada o sin suficientes garantías. La Casa Milá es un buen ejemplo. La utilización del hierro laminado en la Pedrera, que permitió a Gaudí concebir una planta libre independiente de las fachadas —muros-cortina de piedra que parecen desafiar la ley de la gravedad—, ha sido, al mismo tiempo, la causa principal del deterioro de estas fachadas. En el caso de la estructura, la solución conceptual basada en el uso del hierro ha respondido bien a las solicitudes estáticas. No ha ocurrido así con las soluciones —no menos ingeniosas pero excesivamente improvisadas y arriesgadas— previstas, también en base al hierro, para la sustentación de la fachada. Aqu

  18. Estudio de la deficiencia de hierro en pacientes con insuficiencia cardiaca congestiva: una práctica clínica que precisa mayor atención

    Directory of Open Access Journals (Sweden)

    Lara Belmar Vega

    2016-05-01

    Conclusión: La ICC se asocia con alta frecuencia a anemia, deficiencia de hierro e insuficiencia renal. El estudio de los parámetros férricos en los pacientes que ingresan con ICC, pese a que la corrección de la deficiencia de hierro se asocia a mejoría de la sintomatología, no se realiza con la frecuencia necesaria.

  19. Geologic-radiometric techniques applied for uranium prospection at the Hierro-Cayo Largo area

    International Nuclear Information System (INIS)

    Gongora, L.E.; Olivera, J.

    1995-01-01

    Using geologic-radiometric techniques uraniferous anomalies were evaluated at the Hierro-Cayo Largo area located in Pinar del Rio province. During the uranium prospection works at most promising areas, geologic itineraries and gamma ray, radon emanation spectrometric survey were done. Trenches were made and some boreholes were drilled (up to 20-30 m depth). In addition a lot of samples were taken in order to determine the amount of U, Ra, Th, y K by spectrometric techniques. As result of this investigation, a geological placing, a mineralogical and geochemical characteristic of uraniferous mineralization was possible to find out. The appropriate prospection indications for uranium exploration at Esperanza geologic zone were defined

  20. Figuras zoomorfas de barro de la Edad del Hierro en la Meseta Norte

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    Pablo ALONSO HERNÁNDEZ

    2009-11-01

    Full Text Available RESUMEN: En el yacimiento de Las Cogotas, durante la campaña de excavaciones arqueológicas de 1986 apareció una cabeza de caballo, en barro cocido. Es de destacar su interés al igual que el de otras piezas aparecidas en las antiguas excavaciones de este yacimiento (cabeza de serpiente y bóvido. Se trata de importantes ejemplos de figuración zoomorfa en el marco de la Meseta Norte, realizados durante la Segunda Edad del Hierro.ABSTRACT: A horse's head in clay was discovered in the archaeological excavations at Las Cogotas settlement in 1986. This figure and others recovered in the excavations of the 20's (serpent and ox are remarkable in the context of zoomorphic representations of the Meseta Iron Age. They are important examples of the sculpture elaborated by Late Iron Age communitties of the Central Meseta.

  1. Multiparametric statistical investigation of seismicity occurred at El Hierro (Canary Islands) from 2011 to 2014

    Science.gov (United States)

    Telesca, Luciano; Lovallo, Michele; Lopez, Carmen; Marti Molist, Joan

    2016-03-01

    A detailed statistical investigation of the seismicity occurred at El Hierro volcano (Canary Islands) from 2011 to 2014 has been performed by analysing the time variation of four parameters: the Gutenberg-Richter b-value, the local coefficient of variation, the scaling exponent of the magnitude distribution and the main periodicity of the earthquake sequence calculated by using the Schuster's test. These four parameters are good descriptors of the time and magnitude distributions of the seismic sequence, and their variation indicate dynamical changes in the volcanic system. These variations can be attributed to the causes and types of seismicity, thus allowing to distinguish between different host-rock fracturing processes caused by intrusions of magma at different depths and overpressures. The statistical patterns observed among the studied unrest episodes and between them and the eruptive episode of 2011-2012 indicate that the response of the host rock to the deformation imposed by magma intrusion did not differ significantly from one episode to the other, thus suggesting that no significant local stress changes induced by magma intrusion occurred when comparing between all them. Therefore, despite the studied unrest episodes were caused by intrusions of magma at different depths and locations below El Hierro island, the mechanical response of the lithosphere was similar in all cases. This suggests that the reason why the first unrest culminated in an eruption while the other did not, may be related to the role of the regional/local tectonics acting at that moment, rather than to the forceful of magma intrusion.

  2. Observations of coupled seismicity and ground deformation at El Hierro Island (2011-2014)

    Science.gov (United States)

    Gonzalez, P. J.

    2015-12-01

    New insights into the magma storage and evolution at oceanic island volcanoes are now being achieved using remotely sensed space geodetic techniques, namely satellite radar interferometry. Differential radar interferometry is a technique tracking, at high spatial resolution, changes in the travel-time (distance) from the satellites to the ground surface, having wide applications in Earth sciences. Volcanic activity usually is accompanied by surface ground deformation. In many instances, modelling of surface deformation has the great advantage to estimate the magma volume change, a particularly interesting parameter prior to eruptions. Jointly interpreted with petrology, degassing and seismicity, it helps to understand the crustal magmatic systems as a whole. Current (and near-future) radar satellite missions will reduce the revisit time over global sub-aerial volcanoes to a sub-weekly basis, which will increase the potential for its operational use. Time series and filtering processing techniques of such streaming data would allow to track subsurface magma migration with high precision, and frequently update over vast areas (volcanic arcs, large caldera systems, etc.). As an example for the future potential monitoring scenario, we analyze multiple satellite radar data over El Hierro Island (Canary Islands, Spain) to measure and model surface ground deformation. El Hierro has been active for more than 3 years (2011 to 2014). Initial phases of the unrest culminated in a submarine eruption (late 2011 - early 2012). However, after the submarine eruption ended, its magmatic system still active and affected by pseudo-regular energetic seismic swarms, accompanied by surface deformation without resumed eruptions. Such example is a great opportunity to understand the crustal magmatic systems in low magma supply-rate oceanic island volcanoes. This new approach to measure surface deformation processes is yielding an ever richer level of information from volcanology to

  3. Floating sandstones off El Hierro (Canary Islands, Spain): the peculiar case of the October 2011 eruption

    Science.gov (United States)

    Troll, V. R.; Klügel, A.; Longpré, M.-A.; Burchardt, S.; Deegan, F. M.; Carracedo, J. C.; Wiesmaier, S.; Kueppers, U.; Dahren, B.; Blythe, L. S.; Hansteen, T.; Freda, C.; Budd, D. A.; Jolis, E. M.; Jonsson, E.; Meade, F.; Berg, S.; Mancini, L.; Polacci, M.

    2011-12-01

    The eruption that started off the south coast of El Hierro, Canary Islands, in October 2011 has emitted intriguing eruption products found floating in the sea. These specimens appeared as floating volcanic "bombs" that have in the meantime been termed "restingolites" (after the close-by village of La Restinga) and exhibit cores of white and porous pumice-like material. Currently the nature and origin of these "floating stones" is vigorously debated among researchers, with important implications for the interpretation of the hazard potential of the ongoing eruption. The "restingolites" have been proposed to be either (i) juvenile high-silica magma (e.g. rhyolite), (ii) remelted magmatic material (trachyte), (iii) altered volcanic rock, or (iv) reheated hyaloclastites or zeolite from the submarine slopes of El Hierro. Here, we provide evidence that supports yet a different conclusion. We have collected and analysed the structure and composition of samples and compared the results to previous work on similar rocks found in the archipelago. Based on their high silica content, the lack of igneous trace element signatures, and the presence of remnant quartz crystals, jasper fragments and carbonate relicts, we conclude that "restingolites" are in fact xenoliths from pre-island sedimentary rocks that were picked up and heated by the ascending magma causing them to partially melt and vesiculate. They hence represent messengers from depth that help us to understand the interaction between ascending magma and crustal lithologies in the Canary Islands as well as in similar Atlantic islands that rest on sediment/covered ocean crust (e.g. Cape Verdes, Azores). The occurrence of these "restingolites" does therefore not indicate the presence of an explosive high-silica magma that is involved in the ongoing eruption.

  4. Eficiencia productiva de la industria venezolana del hierro en la Región Guayana

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    Jairo J. Pico F.

    2014-01-01

    Full Text Available El objetivo general de la investigación fue analizar la eficiencia productiva de la industria venezolana de Hierro de Reducción Directa (HRD en la Región Guayana en el periodo 2005 al 2009. La investigación fue explicativa. El método aplicadofue el hipotético deductivo con un diseño no experimental de corte transversal. La recolección de datos fue documental y la población fueron los reactores ubicados en la Región Guayana, ya que allí es donde se concentra toda la producción de HRD de Venezuela. La técnica de análisis de los datos aplicada fue Análisis Envolvente de Datos. Los resultados, indican que la producción de HRD está en descenso por la disminución de oferta de insumos (factores externos y la ineficiencia del manejo de insumos (factores internos, siendo la más significativa los factores externos que representa un 74% de la producción y una perdida de 17.569 miles de toneladas, lo que significa un descenso de 1,02 miles de Toneladas anuales en los niveles de producción equivale una pérdida de 23.330 miles de toneladas en el lapso 2005-2009, un 38,7% de producción. Se concluye que es ineludible un cambio de actitud con criterio de competitividad en la conducción de la gestión de los procesos de producción de reducción directa de hierro

  5. Monitoring diffuse degassing in monogentic volcanic field during magmatic reactivation: the case of El Hierro (Canary Islands, Spain)

    Science.gov (United States)

    Morales-Ocaña, C.; Feldman, R. C.; Pointer, Z. R.; Rodríguez, F.; Asensio-Ramos, M.; Melián, G.; Padrón, E.; Hernández, P. A.; Pérez, N. M.

    2017-12-01

    El Hierro (278 km2), the younger, smallest and westernmost island of the Canarian archipelago, is a 5-km-high edifice constructed by rapid constructive and destructive processes in 1.12 Ma, with a truncated trihedron shape and three convergent ridges of volcanic cones. It experienced a submarine eruption from 12 October, 2011 and 5 March 2012, off its southern coast that was the first one to be monitored from the beginning in the Canary Islands. As no visible emanations occur at the surface environment of El Hierro, diffuse degassing studies have become a useful geochemical tool to monitor the volcanic activity in this volcanic island. Diffuse CO2 emission has been monitored at El Hierro Island since 1998 in a yearly basis, with much higher frequency in the period 2011-2012. At each survey, about 600 sampling sites were selected to obtain a homogeneous distribution. Measurements of soil CO2 efflux were performed in situ following the accumulation chamber method. During pre-eruptive and eruptive periods, the diffuse CO2 emission released by the whole island experienced significant increases before the onset of the submarine eruption and the most energetic seismic events of the volcanic-seismic unrest (Melián et al., 2014. J. Geophys. Res. Solid Earth, 119, 6976-6991). The soil CO2 efflux values of the 2017 survey ranged from non-detectable to 53.1 g m-2 d-1. Statistical-graphical analysis of the data show two different geochemical populations; background (B) and peak (P) represented by 77.6% and 22.4% of the total data, respectively, with geometric means of 1.8 and 9.2 g m-2 d-1, respectively. Most of the area showed B values while the P values were mainly observed at the interception center of the three convergent ridges and the north of the island. To estimate the diffuse CO2 emission for the 2017 survey, we ran about 100 sGs simulations. The estimated 2017 diffuse CO2 output released to atmosphere by El Hierro was at 1,150 ± 42 t d-1, value higher than the

  6. Forecasting the 2011 El Hierro submarine eruption (Canary Islands) on the basis of soil He degassing surveys

    Science.gov (United States)

    Padrón, E.; Pérez, N. M.; Hernández, P. A.; Melián, G. V.; Padilla, G. D.; Barrancos, J.; Dionis, S.; Rodríguez, F.; Nolasco, D.; Calvo, D.; Hernández, I.; Peraza, M. D.

    2012-04-01

    El Hierro Island is the southwesternmost and the youngest island of the Canary archipelago. Since 16 July, an anomalous seismicity at El Hierro island was recorded by IGN seismic network. After the occurrence of more than 10,000 seismic events, volcanic tremor was recorded since 05:15 of the October 10, by all of the seismic stations on the island, with highest amplitudes recorded in the southernmost station. During the afternoon of 12 October a large light-green coloured area was observed in the sea to the souht of La Restinga village (at the southernmost part of El Hierro island), suggesting the existence of a submarine eruption. Since October 12, frequent episodes of, turbulent gas emission and foaming, and the appearance of steamy lava fragments has been observed on the sea surface. As part of the volcanic surveillance of the island, the Instituto Volcanologico de Canarias (INVOLCAN) geochemical monitoring program is carrying out diffuse helium surveys on the surface environment of El Hierro (soil atmosphere). This nobel gas has been investigated because it has been considered an almost ideal geochemical indicator because it is chemically inert, physically stable, nonbiogenic, sparingly soluble in water under ambient conditions and almost non-adsorbable. At each survey, 600 sampling sites covering the whole island and following an homogeneous distribution are selected for helium measurements in the soil gases, The helium concentration gradients with respect to its value on air (5.24 ppm) allow us to estimate a pure diffusive emission rate of helium throughout the island. The first survey was carried out on the summer of 2003, when the island was on a quiescence period. At this survey, the amount of helium released by the volcanic system of El Hierro was estimated in 6 kg/d. Since the beginning of the seismic unrest, 13 helium emission surveys have been carried out. The helium emission rate has shown an excellent agreement with the evolution of the volcanic

  7. Soil gas 222Rn and volcanic activity at El Hierro (Canary Islands) before and after the 2011 submarine eruption

    Science.gov (United States)

    Padilla, G.; Hernández, P. A.; Padrón, E.; Barrancos, J.; Melián, G.; Dionis, S.; Rodríguez, F.; Nolasco, D.; Calvo, D.; Hernández, I.; Pereza, M. D.; Pérez, N. M.

    2012-04-01

    El Hierro (278 km2) is the southwesternmost island of the Canarian archipelago. From June 19, 2011 to January 2012, more than 11,950 seismic events have been detected by the seismic network of IGN. On 10 October 2011 the earthquake swarm changed its behaviour and produced a harmonic tremor due to magma movement, indicating that a submarine eruption located at 2 km south of La Restinga had started which is still in progress. Since 2003, the ITER Environmental Research Division now integrated in the Instituto Volcanológico de Canarias, INVOLCAN, has regularly performed soil gas surveys at El Hierro as a geochemical tool for volcanic surveillance. Among the investigated gases, soil gas radon (222Rn) and thoron (220Rn) have played a special attention. Both gases are characterized to ascend towards the surface mainly through cracks or faults via diffusion or advection, mechanisms dependent of both soil porosity and permeability, which in turn vary as a function of the stress/strain changes at depth. Years before the starts of the volcanic-seismic crisis on July 17, 2011, a volcanic multidisciplinary surveillance program was implemented at El Hierro including discrete and continuous measurements of 222Rn and 220Rn. Two soil gas 222Rn surveys had been carried out at El Hierro in 2003 and 2011, and four continuous geochemical monitoring stations for 222Rn and 220Rn measurements had been installed (HIE02, HIE03, HIE04 and HIE08). Soil gas 222Rn surveys were carried out at the surface environment of El Hierro after selecting 600 sampling observation sites (about 40 cm depth). Geochemical stations measure 222Rn and 220Rn activities by pumping the gas from a PVC pipe inserted 1m in the ground and thermally isolated. The results of the 2003 and 2011 soil gas 222Rn surveys show clearly a relatively higher observed 222Rn activities in the surface environment on 2011 than those observed on 2003 when no anomalous seismicity were taking place beneath El Hierro. The observed

  8. Results of LA-ICP-MS sulfide mapping from Algoma-type BIF gold systems with implications for the nature of mineralizing fluids, metal sources, and deposit models

    Science.gov (United States)

    Gourcerol, B.; Kontak, D. J.; Thurston, P. C.; Petrus, J. A.

    2018-01-01

    Quantitative laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) element distribution maps combined with traverse mode analyses have been acquired on various sulfides (pyrite, pyrrhotite, arsenopyrite) from three Canadian Algoma-type BIF-hosted gold deposits ( 4 Moz Au Meadowbank, ≥ 2.8 Moz Au Meliadine district, 6 Moz Au Musselwhite). These data, in conjunction with detailed petrographic and SEM-EDS observations, provide insight into the nature and relative timing of gold events, the presence and implication of trace element zoning regarding crystallization processes, and elemental associations that fingerprint gold events. Furthermore, the use of an innovative method of processing the LA-ICP-MS data in map and traverse modes, whereby the results are fragmented into time-slice data, to generate various binary plots (Ag versus Ni) provides a means to identify elemental associations (Te, Bi) not otherwise apparent. This integrated means of treating geochemical data, along with petrography, allows multiple gold events and remobilization processes to be recognized and their elemental associations determined. The main gold event in each of these deposits is characterized by the coupling of an As-Se-Te-Ag element association coincident with intense stratabound sulfide-replacement of the Fe-rich host rock. Additionally, the data indicate presence of a later remobilization event, which upgraded the Au tenor, as either non-refractory or refractory type, along fracture networks due to the ingress of subsequent base metal-bearing metamorphic fluids (mainly a Pb-Bi association). Furthermore, the data reveal a stratigraphic influence, as reflected in the elemental associations and the elemental enrichments observed and the nature of the sulfide phase hosting the gold mineralization (arsenopyrite versus pyrite).

  9. Biodisponibilidad de diferentes compuestos de hierro añadidos a un néctar de frutas funcional. Interacción con las vitaminas y Fructo-oligosacáridos

    OpenAIRE

    Haro Vicente, Juan Francisco

    2006-01-01

    El enriquecimiento de los alimentos con hierro es considerado una de las estrategias más eficaces en la prevención de la deficiencia en hierro. El éxito del enriquecimiento de los alimentos depende tanto del tipo de alimento como del compuesto de hierro seleccionado. En nuestro estudio se seleccionó un néctar de frutas y varios compuestos de hierro: Pirofosfato férrico micronizado (PFM), Bisglicinato ferroso (BF) y Sulfato ferroso (SF), éste último como referencia, junto con las vitaminas C, ...

  10. Efecto de la concentracion de hidrogeno en la red de hierro bcc por calculos ab-initio

    OpenAIRE

    Sánchez, Javier; Andrés, Pedro L. de; Fullea, J.; Andrade, C.

    2008-01-01

    Utilizando cálculos mecano-cuánticos de primeros principios hemos estudiado la interacción del hidrógeno con la red cúbica centrada en el cuerpo del hierro. El hidrógeno intersticial puede ocupar dos posiciones de alta simetría en la red: el hueco octaédrico y el tetraédrico. Nuestros cálculos nos proporcionan barreras de difusión entre ambos huecos, que analizamos para entender la propagación del hidrogeno a través de la red de hierro. Se ha estudiado el efecto de la concentración de hidróge...

  11. Time lag between deformation and seismicity along monogenetic volcanic unrest periods: The case of El Hierro Island (Canary Islands)

    Science.gov (United States)

    Lamolda, Héctor; Felpeto, Alicia; Bethencourt, Abelardo

    2017-07-01

    Between 2011 and 2014 there were at least seven episodes of magmatic intrusion in El Hierro Island, but only the first one led to a submarine eruption in 2011-2012. In order to study the relationship between GPS deformation and seismicity during these episodes, we compare the temporal evolution of the deformation with the cumulative seismic energy released. In some of the episodes both deformation and seismicity evolve in a very similar way, but in others a time lag appears between them, in which the deformation precedes the seismicity. Furthermore, a linear correlation between decimal logarithm of intruded magma volume and decimal logarithm of total seismic energy released along the different episodes has been observed. Therefore, if a future magmatic intrusion in El Hierro Island follows this behavior with a proper time lag, we could have an a priori estimate on the order of magnitude the seismic energy released would reach.

  12. Study of the thermohygrometric conditions of Juniperus turbinata habitat in the island of El Hierro (Canary Islands)

    Science.gov (United States)

    Salva-Catarineu, Montserrat; Salvador-Franch, Ferran; López-Bustins, Joan Albert; Padrón-Padrón, Perdro A.; Cortés-Lucas, Amparo

    2015-04-01

    The biggest population of Juniperus turbinata throughout the Canary Islands is located in the island of El Hierro. The current extent of juniper woodlands is very small compared with the potential distribution due to heavy exploitation for centuries. Nowadays, the recovery of its natural habitat has such a high environmental and scenic interest since this is a protected species in Europe; however, an improved understanding of the environmental factors that help or limit its recovery is indispensable. Under the JUNITUR project the populations of juniper woodlands in El Hierro are being studied, which are subjected to highly different environments. These environments are mainly determined by their altitude and exposure to NE trade winds. The main objective of this study is to compare the thermohygrometric conditions of three juniper woodlands, located at different altitude and orientation in El Hierro, which present different recovery rates. We are currently using air sensor data loggers fixed to tree branches for recording hourly temperature and humidity data in the three study areas. For this preliminary approach, we analyse daily data of two annual cycles (from September 2012 to August 2014). Our first results show similar thermohygrometric annual cycles among the three study areas. The largest differences are detected in winter temperature and summer humidity between the north (to windward) and south (to leeward) faces of the island. The juniper woodland with a highest recovery rate shows the most extreme temperature conditions in both winter and summer seasons. This last juniper woodland is located leeward to trade winds at 996 m a.s.l. In general terms, the results of this research project might contribute to the knowledge of the juniper bioclimatology in the westernmost of the Canary Islands. Key words: bioclimatology, El Hierro, habitat, Juniperus turbinata, protected species

  13. Prevalencia de deficiencia de hierro y yodo, y parasitosis en niños de Arandas, Jalisco, México

    Directory of Open Access Journals (Sweden)

    Vásquez-Garibay Edgar Manuel

    2002-01-01

    Full Text Available Objetivo. Estimar la prevalencia de deficiencia de hierro, yodo y parasitosis en niños que asisten al Instituto Alteño para el Desarrollo de Jalisco (Inadej, Arandas, Jalisco, México. Material y métodos. Estudio transversal efectuado entre 1997 y 1999 con 432 niños de 12 a 120 meses de edad, de nuevo ingreso al Inadej. Se determinaron variables hematológicas, yodo en orina y presencia de parásitos. Se utilizaron las pruebas Ji cuadrada y t de Student en variables no paramétricas y paramétricas. Resultados. Hubo más anemia (20 vs 7.4% p=0.007 y deficiencia de hierro (60.9 vs 44.4% p=0.02 en prescolares que en escolares. El 29% presentaron deficiencia de yodo (10.5% moderada o grave y 47.2% parasitosis. Predominaron G. lamblia y E. histolytica. Bajo salario, sexo masculino y no tener seguridad social se asociaron con parasitosis. Conclusiones. La elevada prevalencia de deficiencia de hierro, yodo y parasitosis obliga al sector salud estatal a ejecutar medidas eficaces para abatir estas enfermedades prevenibles.

  14. Evidence from acoustic imaging for submarine volcanic activity in 2012 off the west coast of El Hierro (Canary Islands, Spain)

    Science.gov (United States)

    Pérez, Nemesio M.; Somoza, Luis; Hernández, Pedro A.; de Vallejo, Luis González; León, Ricardo; Sagiya, Takeshi; Biain, Ander; González, Francisco J.; Medialdea, Teresa; Barrancos, José; Ibáñez, Jesús; Sumino, Hirochika; Nogami, Kenji; Romero, Carmen

    2014-12-01

    We report precursory geophysical, geodetic, and geochemical signatures of a new submarine volcanic activity observed off the western coast of El Hierro, Canary Islands. Submarine manifestation of this activity has been revealed through acoustic imaging of submarine plumes detected on the 20-kHz chirp parasound subbottom profiler (TOPAS PS18) mounted aboard the Spanish RV Hespérides on June 28, 2012. Five distinct "filament-shaped" acoustic plumes emanating from the flanks of mounds have been recognized at water depth between 64 and 88 m on a submarine platform located NW El Hierro. These plumes were well imaged on TOPAS profiles as "flares" of high acoustic contrast of impedance within the water column. Moreover, visible plumes composed of white rafts floating on the sea surface and sourcing from the location of the submarine plumes were reported by aerial photographs on July 3, 2012, 5 days after acoustic plumes were recorded. In addition, several geophysical and geochemical data support the fact that these submarine vents were preceded by several precursory signatures: (i) a sharp increase of the seismic energy release and the number of daily earthquakes of magnitude ≥2.5 on June 25, 2012, (ii) significant vertical and horizontal displacements observed at the Canary Islands GPS network (Nagoya University-ITER-GRAFCAN) with uplifts up to 3 cm from June 25 to 26, 2012, (iii) an anomalous increase of the soil gas radon activity, from the end of April until the beginning of June reaching peak values of 2.7 kBq/m3 on June 3, 2012, and (iv) observed positive peak in the air-corrected value of 3He/4He ratio monitored in ground waters (8.5 atmospheric 3He/4He ratio ( R A)) at the northwestern El Hierro on June 16, 2012. Combining these submarine and subaerial information, we suggest these plumes are the consequence of submarine vents exhaling volcanic gas mixed with fine ash as consequence of an event of rapid rise of volatile-rich magma beneath the NW submarine ridge

  15. The 2011 submarine volcanic eruption of El Hierro Island (Canary Islands, Spain)

    Science.gov (United States)

    López, C.; Blanco, M. J.

    2012-04-01

    On 10 October 2011 a submarine volcanic eruption began 2 km SW of La Restinga village in the South coast of El Hierro Island (Spain). It became the first submarine eruption reported in 500 years of historical record in the Canary Islands. The eruption took place after three months of intensive seismic activity and ground deformation. The first signal evidencing the eruption was a harmonic tremor signal, located somewhere in the South sector of El Hierro Island and registered in every seismic station on the island. On the following day, the tremoŕs amplitude increased up enough to be felt by the residents of La Restinga. The first visual evidence of the eruption was observed during the afternoon of 12 October, a large light-green coloured area on the sea surface, 2 km to the SW of La Restinga. Three days later, steaming lava fragments were observed floating on the sea, in the area where the vent was supposed to be located. These fragments had a bomb-like shape and their sizes ranged between 10 and 40 cm long. They were bicoloured, a black outer part with a basaltic composition, and a white inner part, highly vesiculated and rich in silica content (>60%). This type of fragments was only observed during the first days of the eruption. Within the next two months further emission episodes have been observed with turbulent water, foam rings and large bubbles on the sea surface. On the 27th of November new lava fragments were observed while floating and degassing on the sea surface. Most of them were "lava balloons" or hollow fragments of lavas, with sizes between 30 and 200 cm, and highly vesiculated outer crust of basaltic-basanitic and sideromelane composition. The emission of these products continues intermitently up to date (January 2012) During the eruption, the GPS monitoring network detected episodes of inflation-deflation and a maximum vertical deformation of 4 cm. The horizontal deformation, which had reached up to 5 cm before the eruption, remains stable. The

  16. Hierro libre, transferrina y ferritina séricas de niños con desnutrición grave en terapia de recuperación nutricional. Turbo-Antioquia 2004

    Directory of Open Access Journals (Sweden)

    Claudia M. Velásquez R.

    2004-02-01

    Full Text Available El hierro libre contribuye a la producción de sustancias oxidativas que alteran la permeabilidad de la membrana celular y originan el edema característico del kwashiorkor (1. La OMS recomienda la suplementación con hierro para niños desnutridos, una vez recuperan el apetito.

  17. Focal mechanism of the seismic series prior to the 2011 El Hierro eruption

    Science.gov (United States)

    del Fresno, C.; Buforn, E.; Cesca, S.; Domínguez Cerdeña, I.

    2015-12-01

    The onset of the submarine eruption of El Hierro (10-Oct-2011) was preceded by three months of low-magnitude seismicity (Mw3.5). Amplitude spectra was fitted at local distances (<20km). Reliability and stability of the results were evaluated with synthetic data. Results show a change in the focal mechanism pattern within the first days of October, varying from complex sources of higher non-double-couple components before that date to a simpler strike-slip mechanism with horizontal tension axes on E-W direction the week prior to the eruption onset. A detailed study was carried out for the 8 October 2011 earthquake (Mw=4.0). Focal mechanism was retrieved using a MT inversion at regional and local distances. Results indicate an important component of strike-slip fault and null isotropic component. The stress pattern obtained corresponds to horizontal compression in a NNW-SSE direction, parallel to the southern ridge of the island, and a quasi-horizontal extension in an EW direction. Finally, a simple source time function of 0.3s has been estimated for this shock using the Empirical Green function methodology.

  18. Long-term volcanic hazard assessment on El Hierro (Canary Islands)

    Science.gov (United States)

    Becerril, L.; Bartolini, S.; Sobradelo, R.; Martí, J.; Morales, J. M.; Galindo, I.

    2014-07-01

    Long-term hazard assessment, one of the bastions of risk-mitigation programs, is required for land-use planning and for developing emergency plans. To ensure quality and representative results, long-term volcanic hazard assessment requires several sequential steps to be completed, which include the compilation of geological and volcanological information, the characterisation of past eruptions, spatial and temporal probabilistic studies, and the simulation of different eruptive scenarios. Despite being a densely populated active volcanic region that receives millions of visitors per year, no systematic hazard assessment has ever been conducted on the Canary Islands. In this paper we focus our attention on El Hierro, the youngest of the Canary Islands and the most recently affected by an eruption. We analyse the past eruptive activity to determine the spatial and temporal probability, and likely style of a future eruption on the island, i.e. the where, when and how. By studying the past eruptive behaviour of the island and assuming that future eruptive patterns will be similar, we aim to identify the most likely volcanic scenarios and corresponding hazards, which include lava flows, pyroclastic fallout and pyroclastic density currents (PDCs). Finally, we estimate their probability of occurrence. The end result, through the combination of the most probable scenarios (lava flows, pyroclastic density currents and ashfall), is the first qualitative integrated volcanic hazard map of the island.

  19. Volcanic signatures in time gravity variations during the volcanic unrest on El Hierro (Canary Islands)

    Science.gov (United States)

    Sainz-Maza Aparicio, S.; Arnoso Sampedro, J.; Gonzalez Montesinos, F.; Martí Molist, J.

    2014-06-01

    Gravity changes occurring during the initial stage of the 2011-2012 El Hierro submarine eruption are interpreted in terms of the preeruptive signatures during the episode of unrest. Continuous gravity measurements were made at two sites on the island using the relative spring gravimeter LaCoste and Romberg gPhone-054. On 15 September 2011, an observed gravity decrease of 45 μGal, associated with the southward migration of seismic epicenters, is consistent with a lateral magma migration that occurred beneath the volcanic edifice, an apparently clear precursor of the eruption that took place 25 days later on 10 October 2011. High-frequency gravity signals also appeared on 6-11 October 2011, pointing to an occurring interaction between a magmatic intrusion and the ocean floor. These important gravity changes, with amplitudes varying from 10 to -90 μGal, during the first 3 days following the onset of the eruption are consistent with the northward migration of the eruptive focus along an active eruptive fissure. An apparent correlation of gravity variations with body tide vertical strain was also noted, which could indicate that concurrent tidal triggering occurred during the initial stage of the eruption.

  20. Searching for structural medium changes during the 2011 El Hierro (Spain) submarine eruption

    Science.gov (United States)

    Sánchez-Pastor, Pilar S.; Schimmel, Martin; López, Carmen

    2017-04-01

    Submarine volcanic eruptions are often difficult to study due to their restricted access that usually inhibits direct observations. That happened with the 2011 El Hierro eruption, which is the first eruption that has been tracked in real time in Canary Islands. For instance, despite the real-time tracking it was not possible to determine the exact end of the eruption. Besides, volcanic eruptions involve many dynamic (physical and chemical) processes, which cause structural changes in the surrounding medium that we expect to observe and monitor through passive seismic approaches. The purpose of this study is to detect and analyse these changes as well as to search for precursory signals to the eruption itself using ambient noise auto and cross-correlations. We employ different correlation strategies (classical and phase cross-correlation) and apply them to field data recorded by the IGN network during 2011 and 2012. The different preprocessing and processing steps are tested and compared to better understand the data, to find the robust signatures, and to define a routine work procedure. One of the problems we face is the presence of volcanic tremors, which cause a varying seismic response that we can not attribute to structural changes. So far, structural changes could not be detected unambiguously and we present our ongoing research in this field.

  1. Monitoring El Hierro submarine volcanic eruption events with a submarine seismic array

    Science.gov (United States)

    Jurado, Maria Jose; Molino, Erik; Lopez, Carmen

    2013-04-01

    A submarine volcanic eruption took place near the southernmost emerged land of the El Hierro Island (Canary Islands, Spain), from October 2011 to February 2012. The Instituto Geografico Nacional (IGN) seismic stations network evidenced seismic unrest since July 2012 and was a reference also to follow the evolution of the seismic activity associated with the volcanic eruption. From the beginning of the eruption a geophone string was installed less than 2 km away from the new volcano, next to La Restinga village shore, to record seismic activity related to the volcanic activity, continuously and with special interest on high frequency events. The seismic array was endowed with 8, high frequency, 3 component, 250 Hz, geophone cable string with a separation of 6 m between them. The analysis of the dataset using spectral techniques allows the characterization of the different phases of the eruption and the study of its dynamics. The correlation of the data analysis results with the observed sea surface activity (ash and lava emission and degassing) and also with the seismic activity recorded by the IGN field seismic monitoring system, allows the identification of different stages suggesting the existence of different signal sources during the volcanic eruption and also the posteruptive record of the degassing activity. The study shows that the high frequency capability of the geophone array allow the study of important features that cannot be registered by the standard seismic stations. The accumulative spectral amplitude show features related to eruptive changes.

  2. The submarine eruption of La Restinga (El Hierro, Canary Islands): October 2011-March 2012; La erupcion submarina de La Restinga en la isla de El Hierro, Canarias: Octubre 2011-Marzo 2012

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Torrado, F J; Carracedo, J C; Rodriguez-Gonzalez, A; Soler, V; Troll, V R; Wiesmaier, S

    2012-11-01

    The first signs of renewed volcanic activity at El Hierro began in July 2011 with the occurrence of abundant, low-magnitude earthquakes. The increasing seismicity culminated on October 10, 2011, with the onset of a submarine eruption about 2 km offshore from La Restinga, the southernmost village on El Hierro. The analysis of seismic and deformation records prior to, and throughout, the eruption allowed the reconstruction of its main phases: 1) ascent of magma and migration of hypo centres from beneath the northern coast (El Golfo) towards the south rift zone, close to La Restinga, probably marking the hydraulic fracturing and the opening of the eruptive conduit; and 2) onset and development of a volcanic eruption indicated by sustained and prolonged harmonic tremor whose intensity varied with time. The features monitored during the eruption include location, depth and morphological evolution of the eruptive source and emission of floating volcanic bombs. These bombs initially showed white, vesiculated cores (originated by partial melting of underlying pre-volcanic sediments upon which the island of El Hierro was constructed) and black basanite rims, and later exclusively hollow basanitic lava balloons. The eruptive products have been matched with a fissural submarine eruption without ever having attained surtseyan explosiveness. The eruption has been active for about five months and ended in March 2012, thus becoming the second longest reported historical eruption in the Canary Islands after the Timanfaya eruption in Lanzarote (1730-1736). This eruption provided the first opportunity in 40 years to manage a volcanic crisis in the Canary Islands and to assess the interpretations and decisions taken, thereby gaining experience for improved management of future volcanic activity. Seismicity and deformation during the eruption were recorded and analysed by the Instituto Geografico Nacional (IGN). Unfortunately, a lack of systematic sampling of erupted pyroclasts and

  3. Tecnología y sociedad en el abastecimiento tradicional de agua en la isla de El Hierro. Canarias.

    Directory of Open Access Journals (Sweden)

    Carlos S. Martín Fernández

    2013-10-01

    Full Text Available Son conocidas las penurias históricas y recientes sufridas en El Hierro para disponer de agua. Los recursos acuíferos herreños, en cantidad y disponibilidad, han sido histórica­mente insuficientes para cubrir la demanda in­sular, siendo éste un factor limitante de prime­ra magnitud en su desarrollo socioeconómico. Hasta la década de 1970 la innova­ción tecnológica en materia hidráulica es nula. Unas pocas fuentes, un número aún menor de pozos y cierta cantidad de charcos formaban los pilares del sistema de abastecimiento co­tidiano de agua. En este artículo, se estudian estos sistemas en conjunción con la dinámica social herreña, planteando la idea de que han sido causas sociales las que explican la se­cular y estrecha dependencia de tecnologías populares para el abastecimiento de agua en El Hierro.There are known the historical and recent penuries suffered in El Hierro to have water. Subsoil’s water, in quantity and availa­bility, has been historically insufficient to cover the insular demand, being this one a limiting factor of first magnitude in his socioeconomic development. Up to the decade of 1970 the techno­logical innovation in hydraulic matter is void. A few fountains, a still minor number of wells and certain quantity of puddles were forming the props of the system of daily water supplying. In this article, these systems are studied in conjunction with the insular’s social dynamics, locating in social causes the explanation of the strait and secular dependency of popular tech­nologies for the water supply.

  4. Seismic tomography model reveals mantle magma sources of recent volcanic activity at El Hierro Island (Canary Islands, Spain)

    Science.gov (United States)

    García-Yeguas, Araceli; Ibáñez, Jesús M.; Koulakov, Ivan; Jakovlev, Andrey; Romero-Ruiz, M. Carmen; Prudencio, Janire

    2014-12-01

    We present a 3-D model of P and S velocities beneath El Hierro Island, constructed using the traveltime data of more than 13 000 local earthquakes recorded by the Instituto Geográfico Nacional (IGN, Spain) in the period from 2011 July to 2012 September. The velocity models were performed using the LOTOS code for iterative passive source tomography. The results of inversion were thoroughly verified using different resolution and robustness tests. The results reveal that the majority of the onshore area of El Hierro is associated with a high-velocity anomaly observed down to 10-12-km depth. This anomaly is interpreted as the accumulation of solid igneous rocks erupted during the last 1 Myr and intrusive magmatic bodies. Below this high-velocity pattern, we observe a low-velocity anomaly, interpreted as a batch of magma coming from the mantle located beneath El Hierro. The boundary between the low- and high-velocity anomalies is marked by a prominent seismicity cluster, thought to represent anomalous stresses due to the interaction of the batch of magma with crust material. The areas of recent eruptions, Orchilla and La Restinga, are associated with low-velocity anomalies surrounding the main high-velocity block. These eruptions took place around the island where the crust is much weaker than the onshore area and where the melted material cannot penetrate. These results put constraints on the geological model that could explain the origin of the volcanism in oceanic islands, such as in the Canaries, which is not yet clearly understood.

  5. Promediando curvas de permeabilidad relativa en yacimientos de metano en mantos de carbón con flujo bifásico en Queensland, Australia.

    Directory of Open Access Journals (Sweden)

    Jorge Ordóñez

    2017-05-01

    Full Text Available En el presente trabajo se propone el uso de un único set de curvas de permeabilidad a ser empleado en los estudios de simulación y caracterización de yacimientos de gas en mantos de carbón (CBM, en vez del uso común de un set de curvas para cada estrato individual. Para comprobar la aplicabilidad de este procedimiento, se simula un yacimiento usando ambos métodos: el resultado de producción debe ser similar en ambas simulacionesEl modelo para promediar la permeabilidad absoluta en un flujo monofásico, fue usado para el caso de predecir un promedio de permeabilidad relativa para un yacimiento con flujo bifásico. Luego de correr varios casos y corroborar que la ecuación propuesta no cumplía las expectativas, el enfoque del trabajo fue explicar el por qué del no funcionamiento de la ecuación propuesta. Una posible explicación fue la no consideración de la gravedad, que acorde a varias simulaciones presentadas, es un parámetro principal en las curvas de producción. La saturación de agua tampoco puede excluirse de la ecuación que prediga este promedio.  Por tanto si se quiere presentar una ecuación para el cálculo de promedio de permeabilidades relativas, es fundamental que tanto la gravedad como la saturación de agua estén incluidas en esta ecuación. Abstract  This paper tries to average relative permeability in a way that instead of using different sets of relative permeability curves to different layers, one single set could be used in one single layer, and to get similar production results as if different layers and different relative permeability were used instead. The model to average absolute permeability in a single-phase flow system was used to predict two-phase flow average relative permeability. After running different cases and corroborating that the equation proposed did not match the expectations. The focus of this work was changed in order to explain why the equation was not working. A possible explanation of

  6. Influência do meio bifásico na multiplicação de gemas e no alongamento de brotos in vitro de Ananas lucidus Miller.

    Directory of Open Access Journals (Sweden)

    Neiliane Santiago Sombra Borges

    2003-06-01

    Full Text Available Este estudo foi realizado no Laboratório de Biotecnologia Vegetal da Embrapa Agroindústria Tropical, em Fortaleza (CE. Nele objetivou-se avaliar a influência do meio de cultura bifásico na multiplicação de gemas e no alongamento de brotos, in vitro, de abacaxi ornamental (Ananas lucidus Miller. Na multiplicação de gemas, utilizaram-se como explantes, brotos de cultura in vitro, com altura aproximada de 0,5 cm. Utilizou-se o meio MS, solidificado e líquido, suplementado com 1,0 mg.L-1 de 6- benzilaminopurina (BAP e 0,1 mg.L-1 de ácido naftaleno-acético (ANA. O delineamento estatístico utilizado foi o inteiramente casualizado com os seguintes tratamentos: acréscimos de 10 mL de meio líquido/frasco nos períodos de cultivo 0; 15; 30; 15 e 30; 30 e 60 e, a cada 15 dias durante 75 dias, com 14 repetições e 6 explantes/parcela. Avaliaram-se os pesos de matéria fresca e de matéria seca aos 90 dias de cultivo. No mesmo período, as culturas de cada tratamento foram transferidas para o meio de cultura de Murashige & Skoog (MS solidificado com 0,4% (p/v de ágar e suplementado com 0,01 mg.L-1 de ANA para o alongamento dos brotos, utilizando, como explante, aglomerado de gemas com aproximadamente 0,5 cm de diâmetro. Cada tratamento foi composto por 6 epetições e 6 explantes/parcela, dispostos em delineamento inteiramente casualizado. Realizaram-se três subcultivos sucessivos para o mesmo meio “novo” a cada 30 dias. Aos 90 dias de cultivo em meio de alongamento avaliaram-se o número de rotos/explante e as porcentagens de número de brotos e de brotos enraizados em quatro amplitudes de altura. Os maiores valores médios para pesos de matéria fresca (913,7 mg/explante e matéria seca (69,1 mg/explante foram obtidos com o acréscimo de 10 mL de meio líquido aos 30 dias de cultivo. Os acréscimos de meio líquido efetuados aos 15 e 30 dias de cultivo proporcionaram a maior média de número de brotos (32,6 brotos/explante aos 90

  7. Estudio del metabolismo del hierro en lactantes de una alta y perenne transmisión de malaria.

    OpenAIRE

    Giménez Gómez, Nuria Pilar

    2003-01-01

    [spa] La malaria y la anemia se encuentran entre los principales problemas de la salud pública mundial. Los recién nacidos y los niños pequeños son uno de los grupos de la población más afectados por ambas patologías. En áreas endémicas de malaria, la frecuente coexistencia de ferropenia, procesos inflamatorios y malaria dificulta la interpretación de las magnitudes bioquímicas utilizadas para valorar el metabolismo del hierro. Otra dificultad añadida en la interpretación de los resultados e...

  8. Estudio del metabolismo del hierro en lactantes de una alta y perenne transmisión de malaria.

    OpenAIRE

    Giménez Gómez, Nuria

    2003-01-01

    La malaria y la anemia se encuentran entre los principales problemas de la salud pública mundial. Los recién nacidos y los niños pequeños son uno de los grupos de la población más afectados por ambas patologías. En áreas endémicas de malaria, la frecuente coexistencia de ferropenia, procesos inflamatorios y malaria dificulta la interpretación de las magnitudes bioquímicas utilizadas para valorar el metabolismo del hierro. Otra dificultad añadida en la interpretación de los resultados es la f...

  9. Anemia y deficiencia de hierro en mujeres en edad reproductiva usuarias del Hospital Regional de Villa Hayes, Paraguay

    OpenAIRE

    Jessica Riveros; Gloria Echagüe; Santiago Evers; Laura Mendoza

    2015-01-01

    La anemia es un problema de salud pública a nivel mundial. En Paraguay, existen datos limitados sobre la frecuencia de anemia en mujeres en edad reproductiva no gestantes. Este estudio piloto descriptivo de corte transverso tuvo como objetivo determinar la frecuencia de anemia y deficiencia de hierro, el estado nutricional, hábitos alimentarios y tóxicos en 99 mujeres no gestantes en edad reproductiva de 18 a 48 años que acudieron al Hospital Regional de Villa Hayes en Octubre del 2.014. La a...

  10. Emporion y las mutaciones de la arquitectura ibérica a la primera Edad de Hierro

    Directory of Open Access Journals (Sweden)

    Pierre MORET

    2009-12-01

    Full Text Available RESUMEN: A partir de las recientes excavaciones de la palaia polis de Empúries, se discute la posibilidad de influjos cruzados entre arquitecturas griega e indígena durante la primera Edad de Hierro en el Languedoc y costas orientales de la península Ibérica.ABSTRACT: Recent excavations at the palaia polis of Emporion (Empúries, Spain give way to a discussion about possible cross-influences between greek domestic architecture and native architecture in Western Languedoc and along the eastern coast of the Iberian Peninsula.

  11. Eighteen years of geochemical monitoring at the oceanic active volcanic island of El Hierro (Canary Islands, Spain)

    Science.gov (United States)

    Asensio-Ramos, María; Alonso, Mar; Sharp, Emerson; Woods, Hannah; Barrancos, José; Pérez, Nemesio M.

    2016-04-01

    We report herein the latest results of a diffuse CO2 efflux survey at El Hierro volcanic system carried out during the summer period of 2015 to constrain the total CO2 output from the studied area a during post-eruptive period. El Hierro Island (278 km2) is the youngest and the SW-most of the Canary Islands. On July 16, 2011, a seismic-volcanic crisis started with the occurrence of more than 11,900 seismic events and significant deformation along the island. On October 10, 2011, the dominant character of seismicity changed dramatically from discrete earthquakes to continuous tremor, a clear indication that magma was rapidly approaching the surface immediately before the onset of the eruption, October 12. Eruption was declared over on 5 March, 2012. In order to monitor the volcanic activity of El Hierro Island, from 1998 to 2015 diffuse CO2 emission studies have been performed at El Hierro volcanic system in a yearly basis (˜600 observation sites) according to the accumulation chamber method. Spatial distribution maps were constructed following the sequential Gaussian simulation (sGs) procedure. To quantify the total CO2 emission from the studied area, 100 simulations for each survey have been performed. During the eruption period, soil CO2 efflux values range from non-detectable (˜0.5 g m-2 d-1) up to 457 g m-2 d-1, reaching in November 27, 2011, the maximum CO2 output estimated value of all time series, 2,398 t d-1, just before the episodes of maximum degassing observed as vigorous bubbling at the sea surface and an increment in the amplitude of the tremor signal. During the 2015 survey, soil CO2 efflux values ranged from non-detectable up to 41 g m-2 d-1. The spatial distribution of diffuse CO2 emission values seemed to be controlled by the main volcano structural features of the island. The total diffuse CO2 output released to atmosphere was estimated at 575 ± 24 t d-1, value slightly higher that the background CO2 emission estimated at 422 t d-1 (Melián et

  12. Suplementación y metabolismo de hierro en neonatos bovinos en condiciones de trópico

    Directory of Open Access Journals (Sweden)

    Paola Andrea Páez

    2013-01-01

    Full Text Available Se estudió el efecto del suministro de hierro en la dinámica hemática y su metabolismo en terneros; para el efecto se seleccionaron 72 neonatos bovinos pertenecientes a tres grupos raciales: dos de origen Bos taurus (Hartón de Valle y Holstein Friesian y uno de origen Bos indicus (Cebú Brahmán para un total de 24 animales por raza y ocho animales por grupo experimental. Los animales del grupo 1 recibieron 500 mg de hierro dextran intramuscular (T1, al grupo 2 se le suministraron 100 mg de espirulina oral (T2 y el grupo 3 permaneció como control (T3. El suministro de hierro se hizo cada mes desde el nacimiento hasta los 6 meses de edad de los terneros, mensualmente se tomaron muestras de sangre mediante venipunción yugular y sistema vacutainer en tubos con y sin anticoagulante (EDTA. El promedio de ganancia de peso vivo animal fue 509 ± 0.40 g/día. El número de leucocitos/mm³ fue de 16,059. El promedio de hemoglobina en sangre fue de 12.11 ± 2.8 g/dl, el hematocrito presentó un valor de 38.4% ± 7.6 y la concentración promedio de hemoglobina corpuscular fue de 31.62% ± 4.7. La proteína sérica presentó un valor promedio de 5.55 ± 0.7 g/dl, el valor promedio de hierro sérico fue de 18.70± 11.8 µmol/lt. Los análisis estadísticos mostraron que el factor mes de muestreo y raza fueron significativos para los valores séricos de los metabolitos analizados, mientras que los valores de la concentración promedio de hemoglobina corpuscular lo fueron para tratamiento (P < 0.01.

  13. Prevalencia de deficiencia de hierro y yodo, y parasitosis en niños de Arandas, Jalisco, México

    OpenAIRE

    Vásquez-Garibay Edgar Manuel; Romero-Velarde Enrique; Nápoles-Rodríguez Francisco; Nuño-Cosío María Eugenia; Trujillo-Contreras Francisco; Sánchez-Mercado Oscar

    2002-01-01

    Objetivo. Estimar la prevalencia de deficiencia de hierro, yodo y parasitosis en niños que asisten al Instituto Alteño para el Desarrollo de Jalisco (Inadej), Arandas, Jalisco, México. Material y métodos. Estudio transversal efectuado entre 1997 y 1999 con 432 niños de 12 a 120 meses de edad, de nuevo ingreso al Inadej. Se determinaron variables hematológicas, yodo en orina y presencia de parásitos. Se utilizaron las pruebas Ji cuadrada y t de Student en variables no paramétricas y paramétric...

  14. Multi-event behavior of El Golfo landslide (El Hierro Island, Canary Archipelago)

    Science.gov (United States)

    León, Ricardo; Biain, Ander; Urgeles, Roger; Somoza, Luis; Ferrer, Mercedes; García-Crespo, Jesús; Francisco Mediato, José; Galindo, Inés; Yepes, Jorge; Gimenez-Moreno, Julia

    2017-04-01

    Based on the re-interpretation of a vast onshore-offshore data set, a new morpho-structural characterization of the El Golfo giant landslide in the island of El Hierro (Canary Archipelago, Spain) is presented. Offshore multibeam echosounder data, chirp sub-bottom profiles, multichannel seismic reflection data and onshore information from water wells and galleries have been analyzed to determine the nature of the event. The subaerial headscarp shows a non-continuous arcuate profile formed by two nested semi-circular amphitheaters that extend offshore along a smooth chute, suggesting the occurrence of at least two large retrogressive events. Channels/gullies and escarpments developed along the submarine sector of the scar also indicate smaller-scale events and predominance of sediment bypass. At the base of submerged island, two subunits within the related submarine mass transport deposit (MTD) are identified on multichannel seismic reflection profiles confirming the multi-event nature of the landslide. The MTD, identified as a debris avalanche, has a total estimated volume of 318 km3: 84 km3 and 234 km3, for the lower and upper subunits respectively. Data from wells and galleries show abrasion platforms with beach deposits at sea-level (0 masl) formed after the landslide scar and buried by the El Golfo post-collapse infill lavas, suggesting an age at least older than 23.5-82.5 ka for the landslide. This work has been supported by the projects IGCP-640 S4SLIDE, High resolution seabed mapping EASME/EMFF/2016/005 and CTM2010-09496-E. Keywords: Submarine landslides, volcanic islands, debris avalanche, Canary Islands

  15. Simulação tridimensional adaptativa da separação das fases de uma mistura bifásica usando a equação de Cahn-Hilliard

    OpenAIRE

    Nós, R.L.; Ceniceros, H.D.; Roma, A.M.

    2012-01-01

    Simulamos a separação dos componentes de uma mistura bifásica com a equação de Cahn-Hilliard. Esta equação contém intrincados termos não lineares e derivadas de alta ordem. Além disso, a delgada região de transição entre os componentes da mistura requer muita resolução. Assim, determinar a solução numérica da equação de Cahn-Hilliard não é uma tarefa fácil, principalmente em três dimensões. Conseguimos a resolução exigida no tempo usando uma discretização semi-implícita de segunda ordem. No e...

  16. Solución analítica del problema directo de la tomografía de capacitancia eléctrica para un fluido bifásico con una inclusión circular

    Directory of Open Access Journals (Sweden)

    Silvia Reyes

    2012-01-01

    Full Text Available En este artículo se expone un modelo matemático al problema de la Tomografía de Capacitancia Eléctrica (TCE, para el caso de un fluido bifásico dieléctrico con una inclusión circular. Se resuelve el problema directo, que consiste en obtener una expresión analítica para las capacitancias mutuas. La solución del problema directo servirá para validar cualquier método de solución al problema inverso, para calibrar los equipos de medición actualmente existentes y además para construir un método de discretización adaptiva para resolver el problema inverso de la TCE.

  17. Magma displacements under insular volcanic fields, applications to eruption forecasting: El Hierro, Canary Islands, 2011-2013

    Science.gov (United States)

    García, A.; Fernández-Ros, A.; Berrocoso, M.; Marrero, J. M.; Prates, G.; De la Cruz-Reyna, S.; Ortiz, R.

    2014-04-01

    Significant deformations, followed by increased seismicity detected since 2011 July at El Hierro, Canary Islands, Spain, prompted the deployment of additional monitoring equipment. The climax of this unrest was a submarine eruption first detected on 2011 October 10, and located at about 2 km SW of La Restinga, southernmost village of El Hierro Island. The eruption ceased on 2012 March 5, after the volcanic tremor signals persistently weakened through 2012 February. However, the seismic activity did not end with the eruption, as several other seismic crises followed. The seismic episodes presented a characteristic pattern: over a few days the number and magnitude of seismic event increased persistently, culminating in seismic events severe enough to be felt all over the island. Those crises occurred in 2011 November, 2012 June and September, 2012 December to 2013 January and in 2013 March-April. In all cases the seismic unrest was preceded by significant deformations measured on the island's surface that continued during the whole episode. Analysis of the available GPS and seismic data suggests that several magma displacement processes occurred at depth from the beginning of the unrest. The first main magma movement or `injection' culminated with the 2011 October submarine eruption. A model combining the geometry of the magma injection process and the variations in seismic energy release has allowed successful forecasting of the new-vent opening.

  18. The submarine volcano eruption at the island of El Hierro: physical-chemical perturbation and biological response

    Science.gov (United States)

    Fraile-Nuez, E.; Santana-Casiano, J.; Gonzalez-Davila, M.

    2013-12-01

    On October 10 2011 an underwater eruption gave rise to a novel shallow submarine volcano south of the island of El Hierro, Canary Islands, Spain. During the eruption large quantities of mantle-derived gases, solutes and heat were released into the surrounding waters. In order to monitor the impact of the eruption on the marine ecosystem, periodic multidisciplinary cruises were carried out. Here, we present an initial report of the extreme physical-chemical perturbations caused by this event, comprising thermal changes, water acidification, deoxygenation and metal-enrichment, which resulted in significant alterations to the activity and composition of local plankton communities. Our findings highlight the potential role of this eruptive process as a natural ecosystem-scale experiment for the study of extreme effects of global change stressors on marine environments. (A) Natural color composite from the MEdium Resolution Imaging Spectrometer (MERIS) instrument aboard ENVISAT Satellite (European Space Agency), (November 9, 2011 at 14:45 UTC). Remote sensing data have been used to monitor the evolution of the volcanic emissions, playing a fundamental role during field cruises in guiding the Spanish government oceanographic vessel to the appropriate sampling areas. The inset map shows the position of Canary Islands west of Africa and the study area (solid white box). (B) Location of the stations carried out from November 2011 to February 2012 at El Hierro. Black lines denote transects A-B and C-D.

  19. Diffuse degassing He/CO2 ratio before and during the 2011-12 El Hierro submarine eruption, Canary Islands

    Science.gov (United States)

    Padrón, Eleazar; Hernández, Pedro A.; Melián, Gladys V.; Barrancos, José; Padilla, Germán; Pérez, Nemesio M.; Dionis, Samara; Rodríguez, Fátima; Asensio-Ramos, María; Calvo, David

    2015-04-01

    El Hierro Island (278 km2) is the youngest and the SW-most of the Canary Islands. On July 16, 2011, a seismic-volcanic crisis started with the occurrence of more than 11,900 seismic events and significant deformation along the island, culminating with the eruption onset in October 12. Since at El Hierro Islands there are not any surface geothermal manifestation (fumaroles, etc), we have focused our studies on soil degassing surveys. Between July 2011 to March 2012, seventeen diffuse CO2 and He emissions soil gas surveys were undertaken at El Hierro volcanic system (600 observation sites) with the aim to investigate the relationship between their temporal variations and the volcanic activity (Padrón et al., 2013; Melián et al., 2014). Based on the diffuse He/CO2 emission ratio, a sharp increase before the eruption onset was observed, reaching the maximum value on September 26 (6.8×10-5), sixteen days before the occurrence of the eruption. This increase coincided with an increase in seismic energy release during the volcanic unrest and occurred together with an increase on the 3He/4He isotopic ratio in groundwaters from a well in El Hierro Island (Padrón et al., 2013; from 2-3 RA to 7.2 RA where RA = 3He/4He ratio in air), one month prior to the eruption onset. Early degassing of new gas-rich magma batch at depth could explain the observed increase on the He/CO2 ratio, causing a preferential partitioning of CO2 in the gas phase with respect to the He, due to the lower solubility of CO2 than that of He in basaltic magmas. During the eruptive period (October 2011-March 2012) the prevalence of a magmatic CO2-dominated component is evident, as indicated by the generally lower He/CO2 ratios and high 3He/4He values (Padrón et al., 2013). The onset of the submarine eruption might have produced a sudden release of volcanic gases, and consequently, a decrease in the volcanic gas pressure of the magma bodies moving beneath the island, reflected by a drastic decrease in

  20. Estado nutricional del hierro en gestantes adolescentes, Medellín, Colombia / Nutritional status of iron in pregnant adolescents, Medellín, Colombia

    Directory of Open Access Journals (Sweden)

    Beatriz E. Parra S

    2014-04-01

    Full Text Available Objetivo: analizar el estado nutricional del hierro en gestantes adolescentes de tercer trimestre. Metodología: estudio analítico de corte transversal con 276 adolescentes entre 10 y 19 años, en tercer trimestre de gestación de la Empresa Social del Estado (ese Metrosalud (Medellín, 2011-2012, con datos de hemoglobina, volumen corpuscular medio, concentración de hemoglobina corpuscular media e ingesta de suplemento de hierro. La ferritina sérica se analizó en 178 gestantes, controlada por proteína C-reactiva. Se utilizaron medidas de tendencia central, dispersión, porcentajes y pruebas de Chi2 , anova, Kruskal-Wallis y U de Mann-Whitney. Resultados: la prevalencia de anemia fue 17,1% en el tercer trimestre de gestación y por deficiencia de hierro, 51%. La mediana de ferritina sérica fue 13,3 µg/L (RQ: 7,7 µg/L-17,9 µg/L; sólo el 5,6% (n = 9 presentó valores adecuados de ferritina. Las madres que tomaron suplemento de hierro diariamente presentaron mejores concentraciones de hemoglobina y ferritina, frente a aquellas que no lo hicieron, Hb 12,1g/dL vs. 11,7 g/dL (p = 0,019 y ferritina sérica 14,6 µg/L vs. 7,0 µg/L (p = 0,000. Discusión: hubo altas prevalencias de anemia y ferropenia en las gestantes, asociadas con la no adherencia al suplemento de hierro Objetivo: analizar el estado nutricional del hierro en gestantes adolescentes de tercer trimestre. Metodología: estudio analítico de corte transversal con 276 adolescentes entre 10 y 19 años, en tercer trimestre de gestación de la Empresa Social del Estado (ese Metrosalud (Medellín, 2011-2012, con datos de hemoglobina, volumen corpuscular medio, concentración de hemoglobina corpuscular media e ingesta de suplemento de hierro. La ferritina sérica se analizó en 178 gestantes, controlada por proteína C-reactiva. Se utilizaron medidas de tendencia central, dispersión, porcentajes y pruebas de Chi2 , anova, Kruskal-Wallis y U de Mann-Whitney. Resultados: la prevalencia

  1. Time-dependent deformation at elevated temperatures in basalt from El Hierro, Stromboli and Teide volcanoes

    Science.gov (United States)

    Benson, P. M.; Fahrner, D.; Harnett, C. E.; Fazio, M.

    2014-12-01

    Time dependent deformation describes the process whereby brittle materials deform at a stress level below their short-term material strength (Ss), but over an extended time frame. Although generally well understood in engineering (where it is known as static fatigue or "creep"), knowledge of how rocks creep and fail has wide ramifications in areas as diverse as mine tunnel supports and the long term stability of critically loaded rock slopes. A particular hazard relates to the instability of volcano flanks. A large number of flank collapses are known such as Stromboli (Aeolian islands), Teide, and El Hierro (Canary Islands). Collapses on volcanic islands are especially complex as they necessarily involve the combination of active tectonics, heat, and fluids. Not only does the volcanic system generate stresses that reach close to the failure strength of the rocks involved, but when combined with active pore fluid the process of stress corrosion allows the rock mass to deform and creep at stresses far lower than Ss. Despite the obvious geological hazard that edifice failure poses, the phenomenon of creep in volcanic rocks at elevated temperatures has yet to be thoroughly investigated in a well controlled laboratory setting. We present new data using rocks taken from Stromboli, El Heirro and Teide volcanoes in order to better understand the interplay between the fundamental rock mechanics of these basalts and the effects of elevated temperature fluids (activating stress corrosion mechanisms). Experiments were conducted over short (30-60 minute) and long (8-10 hour) time scales. For this, we use the method of Heap et al., (2011) to impose a constant stress (creep) domain deformation monitored via non-contact axial displacement transducers. This is achieved via a conventional triaxial cell to impose shallow conditions of pressure (<25 MPa) and temperature (<200 °C), and equipped with a 3D laboratory seismicity array (known as acoustic emission, AE) to monitor the micro

  2. Improvements on the seismic catalog previous to the 2011 El Hierro eruption.

    Science.gov (United States)

    Domínguez Cerdeña, Itahiza; del Fresno, Carmen

    2017-04-01

    Precursors from the submarine eruption of El Hierro (Canary Islands) in 2011 included 10,000 low magnitude earthquakes and 5 cm crustal deformation within 81 days previous to the eruption onset on the 10th October. Seismicity revealed a 20 km horizontal migration from the North to the South of the island and depths ranging from 10 and 17 km with deeper events occurring further South. The earthquakes of the seismic catalog were manually picked by the IGN almost in real time, but there has not been a subsequent revision to check for new non located events jet and the completeness magnitude for the seismic catalog have strong changes during the entire swarm due to the variable number of events per day. In this work we used different techniques to improve the quality of the seismic catalog. First we applied different automatic algorithms to detect new events including the LTA-STA method. Then, we performed a semiautomatic system to correlate the new P and S detections with known phases from the original catalog. The new detected earthquakes were also located using Hypoellipse algorithm. The resulting new catalog included 15,000 new events mainly concentrated in the last weeks of the swarm and we assure a completeness magnitude of 1.2 during the whole series. As the seismicity from the original catalog was already relocated using hypoDD algorithm, we improved the location of the new events using a master-cluster relocation. This method consists in relocating earthquakes towards a cluster of well located events instead of a single event as the master-event method. In our case this cluster correspond to the relocated earthquakes from the original catalog. Finally, we obtained a new equation for the local magnitude estimation which allow us to include corrections for each seismic station in order to avoid local effects. The resulting magnitude catalog has a better fit with the moment magnitude catalog obtained for the strong earthquakes of this series in previous studies

  3. Procesado y propiedades de impacto de materiales compuestos laminados de base hierro

    Directory of Open Access Journals (Sweden)

    Carreño, F.

    2001-04-01

    Full Text Available A seven layers steel based laminated composite (four ultra-high carbon steel, UHCS, layers and three mild steel, MS, layers has been processed by rolling bonding and its microstructure and impact properties have been studied. Suitable parameters of temperature and thickness reduction were selected to obtain a finer microstructure relative to the original material components. This finer microstructure induces improved mechanical properties. Charpy impact tests values in both "crack arrester" and "crack divider" orientations improve the values of the UHCS constituent material. Furthermore, the crack arrester orientation value exceed that of the MS material. The delamination, which is controlled by interface bonding, plays a key role deflecting the crack, absorbing energy and imposing the nucleation of new cracks in the next material layer.

    Se ha procesado un material compuesto laminado de base hierro, de 7 capas alternas de dos aceros diferentes (cuatro capas de acero de ultra-alto contenido en carbono, AUAC, y tres de acero suave, AS, mediante unión por laminación y se ha estudiado su microestructura y propiedades de impacto. Se eligieron los parámetros adecuados de temperatura y de reducción de espesor para obtener una microestructura más fina que la de los aceros constituyentes originales, lo que induce una mejora en las propiedades mecánicas. Los valores de energía absorbida en el ensayo Charpy, tanto en la dirección "en paralelo" como "en serie", han mejorado sustancialmente el valor asociado al AU AC monolítico. Además, el valor obtenido en la dirección "en serie" es superior al del AS. Se observa que la delaminación, que depende de la unión de las intercaras, juega un papel importante en la deflexión de las fisuras, absorbiendo energía e imponiendo sucesivas nucleaciones de grietas en las siguientes capas.

  4. On the relation between crustal deformation and seismicity during the 2012-2014 magmatic intrusions in El Hierro island.

    Science.gov (United States)

    Domínguez Cerdeña, Itahiza; García-Cañada, Laura; Ángeles Benito Saz, María; Del Fresno, Carmen

    2017-04-01

    The last volcanic eruption in the Canary Islands took place in 2011 less than 2 km offshore El Hierro island, after 3 months of measuring surface deformation (up to 5 cm) and locating more than 10 000 earthquakes. In the two years following the end of the submarine eruption on 5 March 2012, six deep magmatic intrusions were recorded beneath the island. Despite the short time duration of these intrusions, these events have been more energetic that the 2011 pre-eruptive intrusive event but none of them ended in a new eruption. These post-eruptive reactivations are some of the few examples in the world of well monitored magmatic intrusions related with monogenetic volcanism. In order to understand these processes we have analyzed the geodetic and seismic data with different techniques. First, we did a joint hypocentral relocation of the six seismic swarms, including more than 6 300 events, to analyze the relative distribution of the earthquakes from different intrusions. The uncertainties of the earthquakes relocations was reduced to an average value of 300 m. New earthquakes' distribution shows the alignments of the different intrusions and a temporal migration of the events to larger depths. Moreover, we show the results of the ground deformation using GPS data from the network installed on the island (for each of the six intrusive events) and their inversion considering spherical models. In most of the intrusions the optimal source model was shallower and southern than the corresponding seismicity hypocenters. The intruded magma volume ranges from 0.02 to 0.13 km3. Finally, we also computed the b value from the Gutenberg Richter equation by means of a bootstrap method. The spatial and temporal evolution of the b value for the seismicity show a clear correlation with the temporal evolution of the crustal deformation. The six magma intrusions can be grouped, depending on their location, in three pairs each one associated with each of the three active rifts of El

  5. Iron status in spanish junior soccer and basketball players. Status en hierro de jugadores de fútbol y baloncesto de la categoría junior.

    Directory of Open Access Journals (Sweden)

    Valtueña , Jara

    2006-07-01

    Full Text Available AbstractAim: To assess the dietary iron intake and the iron status of Spanish junior athletes and its importance on performance, and to discuss abount the consequences of an iron deficiency. Material and methods: Forty six soccer and eleven basketball players aged 17-21 years (mean age 18.2 +1.1 who played in the Spanish national junior soccer and basketball league, respectively, who had neither drugs, medicines intake nor illness during the study which altered the appetite or some studies parameters, took part in the study. Dietary intake was assessed by means of a 7-day weighed food intake record. Iron status was evaluated by means of a complete hemogram, serum iron, ferritin, transferrin and TIBC.Results: Mean iron intake was 19.24±4.58 mg/day. Mean analytical data were all between reference ranges. Basketball players had higher intake levels compared with soccer ones (22.1+6.4 and 19.2+3.9 mg/day, respectively; pConclusions: During adolescence, iron requirements are very high which could place adolescent athletes in a high risk group for iron deficiency and iron deficiency anaemia. In the current research, the population studied shows an acceptable iron status although there are 3% of iron deficiency anaemia cases.ResumenObjetivos: valorar la ingesta diaria y el estatus de hierro de los atletas junior españoles y su importancia sobre el rendimiento, así como lo que respecta a las consecuencias que tiene una deficiencia de hierro. Material y métodos: cuarenta y seis jugadores de fútbol y once de baloncesto con edades comprendidas entre los 17 y 21 años (la media de edad 18.2 + 1.1 que jugaban en la liga junior nacional de fútbol y baloncesto, respectivamente, y que no tomaban drogas, medicinas ni presentaban ninguna enfermedad durante el desarrollo del estudio que pudiera alterar el apetito o algunos de los parámetros objeto de estudio, tomaron parte en este estudio. La ingesta dietética se cuantificó mediante la técnica de

  6. Paralelos arquitectónicos entre la meseta norte y el alto Tajo durante la II Edad del Hierro

    Directory of Open Access Journals (Sweden)

    María Concepción BLASCO BOSQUED

    2009-10-01

    Full Text Available Son muchos los autores que, al estudiar la II Edad del Hierro en la Meseta, han hecho referencia a la dificultad que existe para precisar unos límites exactos del mundo celtibérico, no existiendo ni siquiera un acuerdo unánime sobre qué tribus lo integran. La causa de este hecho estriba en que, generalmente, se utilizan para ello los datos históricos y éstos, sin ser despreciables, resultan muchas veces poco precisos. Por todo ello F. Wattenberg apuntaba que el problema fundamental «no es el de aceptar las valoraciones de algunas fuentes, sino el de justificarlas».

  7. Diffuse CO_{2} degassing monitoring of the oceanic active volcanic island of El Hierro, Canary Islands, Spain

    Science.gov (United States)

    Hernández, Pedro A.; Norrie, Janice; Withoos, Yannick; García-Merino, Marta; Melián, Gladys; Padrón, Eleazar; Barrancos, José; Padilla, Germán; Rodríguez, Fátima; Pérez, Nemesio M.

    2017-04-01

    Even during repose periods, volcanoes release large amounts of gases from both visible (fumaroles, solfataras, plumes) and non-visible emanations (diffuse degassing). In the last 20 years, there has been considerable interest in the study of diffuse degassing as a powerful tool in volcano monitoring programs, particularly in those volcanic areas where there are no visible volcanic-hydrothermal gas emissions. Historically, soil gas and diffuse degassing surveys in volcanic environments have focused mainly on CO2 because it is, after water vapor, the most abundant gas dissolved in magma. As CO2 travels upward by advective-diffusive transport mechanisms and manifests itself at the surface, changes in its flux pattern over time provide important information for monitoring volcanic and seismic activity. Since 1998, diffuse CO2 emission has been monitored at El Hierro Island, the smallest and south westernmost island of the Canarian archipelago with an area of 278 km2. As no visible emanations occur at the surface environment of El Hierro, diffuse degassing studies have become the most useful geochemical tool to monitor the volcanic activity in this volcanic island. The island experienced a volcano-seismic unrest that began in July 2011, characterized by the location of a large number of relatively small earthquakes (MHierro at depths between 8 and 15 km. On October 12, 2011, a submarine eruption was confirmed during the afternoon of October 12, 2011 by visual observations off the coast of El Hierro, about 2 km south of the small village of La Restinga in the southernmost part of the island. During the pre-eruptive and eruptive periods, the time series of the diffuse CO2 emission released by the whole island experienced two significant increases. The first started almost 2 weeks before the onset of the submarine eruption, reflecting a clear geochemical anomaly in CO2 emission, most likely due to increasing release of deep seated magmatic gases to the surface. The second

  8. Results of radical radiotherapy of oropharyngeal squamous cell carcinoma: experience at the clinical Puerta de Hierro (Spain)

    International Nuclear Information System (INIS)

    Regueiro, C.A.; Valcarcel, F.J.; Millan, I.; Romero, J.; Torre, A. de la; Polo, E.; Magallon, R.; Aragon, G.

    1994-01-01

    We have reviewed the records of 251 patients with oropharyngeal squamous cell carcinoma treated with radical radiotherapy at the Department of Radiation Oncology of Clinica Puerta de Hierro between 1964 and 1989. The 3-year actuarial local control probability was 85% for the 29 T1-staged patients, 59% for the 89 T2-staged patients, 45% for the 71 T3-staged patients, and 43% for the 62 T4-staged patients. The 3-year actuarial nodal control probability was 86% for the 103 NO-staged patients treated electively, 66% for the 42 N1-staged patients, 60% for the 77 N2-staged patients, and 51% for the 20 N3-staged patients. The actuarial adjusted survival was 68% for the 17 stage I patients, 69% for the 48 stage II patients, 34% for the 57 stage III patients, and 33% for the 129 stage IV patients. Author (50 refs.)

  9. Formas de hierro y aluminio en suelos con diferentes usos en la zona norte del departamento del Magdalena, Colombia

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    José Rafael Vásquez Polo

    2014-12-01

    Full Text Available En el estudio se evaluaron las diferentes formas de hierro (Fe y aluminio (Al presentes en suelos cultivados y en áreas de bosque de la zona norte del departamento del Magdalena (Colombia. Se seleccionaron seis zonas de muestreo localizadas entre 0 y 1000 m.s.n.m. Se utilizaron tres técnicas selectivas de extracción de Fe y Al con los agentes extractantes: pirofosfato de sodio, oxalato ácido de amonio, y ditionito citrato bicarbonato. Los contenidos totales de Fe y Al fueron determinados mediante un ataque ácido y cuantificación por absorción atómica. El análisis de varianza multivariado mostró diferencias significativas (P 3% del Al total, lo que sugiere que un alto contenido de Al forma parte de estructuras cristalinas.

  10. Mantle to surface degassing of carbon- and sulphur-rich alkaline magma at El Hierro, Canary Islands

    Science.gov (United States)

    Longpré, Marc-Antoine; Stix, John; Klügel, Andreas; Shimizu, Nobumichi

    2017-02-01

    Basaltic volcanoes transfer volatiles from the mantle to the surface of the Earth. The quantification of deep volatile fluxes relies heavily on estimates of the volatile content of primitive magmas, the best archive of which is provided by melt inclusions. Available data from volcanoes producing mafic alkaline lavas in a range of tectonic settings suggest high volatile fluxes, but information remains sparse, particularly for intraplate ocean islands. Here we present measurements of volatile and trace element concentrations, as well as sulphur speciation, in olivine-hosted melt inclusions and matrix glasses from quenched basanite lava balloon samples from the 2011-2012 submarine eruption at El Hierro, Canary Islands. The results reveal remarkably high concentrations of dissolved volatiles and incompatible trace elements in this magma, with ∼80 ppm Nb and up to 3420 ppm CO2, 3.0 wt.% H2O and 5080 ppm S. Reconstructed primitive CO2 contents, considering CO2/Nb systematics and possible CO2 sequestration in shrinkage bubbles, reach weight percent levels, indicating that carbon is a major constituent of Canary Island magmas at depth and that exsolution of a CO2-rich fluid begins in the mantle at pressures in excess of 1 GPa. Correlations between sulphur concentration, sulphur speciation and water content suggest strong reduction of an initially oxidised mantle magma, likely controlled by coupled H2O and S degassing. This late-stage redox change may have triggered sulphide saturation, recorded by globular sulphide inclusions in clinopyroxene and ulvöspinel. The El Hierro basanite thus had a particularly high volatile-carrying capacity and released a minimum of 1.3-2.1 Tg CO2 and 1.8-2.9 Tg S to the environment, causing substantial stress on the local submarine ecosystem. These results highlight the important contribution of alkaline ocean island volcanoes, such as the Canary Islands, to volatile fluxes from the mantle.

  11. Anemia y deficiencia de hierro en mujeres en edad reproductiva usuarias del Hospital Regional de Villa Hayes, Paraguay

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    Jessica Riveros

    2015-08-01

    Full Text Available La anemia es un problema de salud pública a nivel mundial. En Paraguay, existen datos limitados sobre la frecuencia de anemia en mujeres en edad reproductiva no gestantes. Este estudio piloto descriptivo de corte transverso tuvo como objetivo determinar la frecuencia de anemia y deficiencia de hierro, el estado nutricional, hábitos alimentarios y tóxicos en 99 mujeres no gestantes en edad reproductiva de 18 a 48 años que acudieron al Hospital Regional de Villa Hayes en Octubre del 2.014. La anemia se determinó tomando como punto de corte una concentración de hemoglobina <12 g/dL. La deficiencia de hierro se evaluó según la saturación de la transferrina. Además, se evaluó el índice de masa corporal (IMC y los hábitos nutricionales a través de una encuesta. La frecuencia de anemia fue de 15,1% (IC95% 8,7-23,8%, de éste el 33,3% (IC95% 12,8-61,6% correspondió a anemia ferropénica. Se observó asociación entre la presencia de anemia y los niveles disminuidos tanto del hematocrito (<38% como del número de glóbulos rojos (<4,2x 106/uL. Todas las mujeres con anemia ferropénica tenían peso <64 kg e IMC <24,5 kg/m2. Además, se detectó una alta frecuencia de sobrepeso y obesidad (45,4%, alto consumo de grasas, y bajo consumo de legumbres, frutas y verduras. A partir de estos resultados, se sugiere mantener la vigilancia e implementar programas que incluyan a estas mujeres, tanto para evitar deficiencias nutricionales como excesos.

  12. Quelato de hierro y agua de coco en la germinación in vitro de Rossioglossum grande (Orchidaceae

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    Vincenzo Bertolini

    2014-09-01

    Full Text Available Rossioglossum grande (Lindl. Garay & G.C. Kenn es una orquídea nativa mexicana, considerada en peligro de extinción por la NOM-059-Semarnat-2010. Teniendo en cuenta que la germinación asimbiótica in vitro es una herramienta estratégica para la conservación de orquídeas amenazadas, en este estudio se generó información básica mediante la comparación de la germinación de R. grande en medios Knudson C (KC y Dalla Rosa y Laneri modificado con quelato de hierro y agua de coco (DR. Para el efecto se utilizaron un cultivo madre (CM y dos subcultivos (C1 y C2 y los tratamientos se dispusieron en un diseño experimental totalmente aleatorio. Los resultados se analizaron mediante análisis de varianza y comparación de medias con la prueba de Tukey (P < 0.05 y Chi-cuadrada. A 60 días en el CM el medio de cultivo DR favoreció el desarrollo, la tasa de sobrevivencia y disminuyó la clorosis de los protocormos. A los 12 meses se presentó mayor desarrollo y mayor regeneración de protocormos. En los subcultivos C1 y C2 se registraron resultados similares lo que confirma que el DR acelera el desarrollo de los protocormos e incrementa su tamaño y tasa de regeneración. En síntesis, el empleo de hierro-quelato y agua de coco promueven el desarrollo in vitro de protocormos de R. grande.

  13. FORMULACIÓN DE UNA BEBIDA LÁCTEA CON SABOR A AREQUIPE ENRIQUECIDA CON HIERRO Y ÁCIDO FÓLICO, DIRIGIDA A MUJERES GESTANTES

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    Jhon Jairo Bejarano Roncancio

    2011-03-01

    Full Text Available Antecedentes. Colombia se encuentra dentro de los países con prevalencia moderada de anemia en mujeres gestantes (20-40%; está comprobado que los niveles séricos de folato y hierro en la madre son factores bioquímicos relevantes para la formación del bebé. Dichas aseveraciones, justifican la formulación de un producto alimenticio enriquecido con hierro y ácido fólico,  específico para mujeres gestantes y que contribuya a mejorar sus condiciones nutricionales. Objetivo. Desarrollar una bebida láctea enriquecida con hierro y ácido fólico, endulzada y con sabor a arequipe, organolépticamente aceptable. Materiales y métodos. Para su desarrollo, se cumplieron dos etapas básicas: formulación del patrón y formulación del producto. El enriquecimiento del producto inicial  se hizo con hierro y ácido fólico y luego se determinó  la aceptación organoléptica final. Resultados. La formulación de la bebida láctea Mamá vitae sabor a arequipe, tuvo 86% de aceptación, e incluyó 10 mg de hierro aminoquelado y 230 µg de pteroilmonoglutamato por porción de 200 mL de leche; aportó el 17% de las recomendaciones de hierro y el 33% del ácido fólico para una mujer en gestación. Conclusión. Las características del producto favorecen unas mejores condiciones nutricionales a la gestante y a las mujeres fértiles que quieren planificar una gestación viable. Este tipo de productos son epidemiológicamente necesarios para poblaciones vulnerables como las mujeres gestantes y lactantes.

  14. Estudio y modelación del flujo bifásico líquido-gas para bajos valores de Reynolds//Study and modelation for low reynolds value of two phases flow liquid-gas

    Directory of Open Access Journals (Sweden)

    Annamaris Olmo Velázquez

    2015-01-01

    Full Text Available El flujo simultáneo de líquido y gas es una de las combinaciones más complejas de flujo bifásico. Para este estudio se seleccionaron como fluidos de trabajo Glicerina en solución con agua al 80 % y Gel industrial. Estos por sus viscosidades permiten establecer los sistemas deseados para el estudio, con valores de Reynolds menor a 15. Fueron desarrollados experimentos para la determinación de las propiedades hidrodinámicas del los fluidos y los parámetros que caracterizan este tipo de flujo en un canal vertical. Fue obtenido a partir del análisis físico matemático de losexperimentos realizados, un modelo teórico experimental capaz de evaluar las fuerzas y coeficientes de arrastre para una burbuja aislada y un tren de burbujas. Se realizaron modelaciones computacionales de los distintos regímenes de trabajo, validadas con los resultados experimentales. Obteniéndose simulaciones y resultados que permiten visualizar y analizar el comportamiento real del sistema.Palabras claves: flujo bifásico, número de Reynolds, burbuja aislada, tren de burbujas, coeficientes de arrastre, fuerzas de arrastre._________________________________________________________________________________AbstractThe study of simultaneous flow of liquid and gas over a conduit is two phases flow combinations more complex that exist. For the study we select fluid (glycerin in solution with water (80 % and industrial gel that establish flow models necessary for the investigation the desired systems. And is obtained from physical-mathematical analysis of obtained results made experiment for different configurations, a theorys experimental model have evaluate the drag coefficient and force acting on only bubble and train bubbles in job regimen for Reynolds value less and equal to 15. In the present study was performed computational modeling of different patterns, validated with experimental results.Simulations and results obtained for visualizing and analyzing the actual

  15. Turbulência induzida por jatos bifásicos do tipo gás-líquido em tanques de aeração Turbulence induced by two-phase gas-liquid jets in aeration tanks

    Directory of Open Access Journals (Sweden)

    Iran Eduardo Lima Neto

    2010-03-01

    Full Text Available Jatos bifásicos do tipo gás-líquido são bastante usados nas engenharias sanitária e ambiental para fins de aeração artificial e mistura turbulenta. O presente trabalho investiga a turbulência gerada por meio desses jatos em um tanque de água, utilizando velocimetria por imagem de partículas. As condições experimentais incluíram jatos bifásicos com frações volumétricas de ar de até 70% e números de Reynolds variando entre 10.600 e 17.700. Os resultados dos ensaios indicaram que a fração volumétrica de ar afeta consideravelmente as propriedades turbulentas da fase líquida, enquanto o número de Reynolds apresenta efeito secundário. Correlações adimensionais foram então obtidas para expressar a energia cinética turbulenta e a taxa de dissipação de energia em função desses dois parâmetros. Finalmente, são apresentadas possíveis aplicações dos resultados deste trabalho.Two-phase gas-liquid jets are widely used in the sanitary and environmental engineering field for artificial aeration and turbulent mixing. The present work investigates the turbulence generated by these jets in a water tank, using particle image velocimetry. The experimental conditions included two-phase jets with gas volume fractions of up to 70% and Reynolds numbers ranging from 10,600 to 17,700. The results indicated that the gas volume fraction affects significantly the turbulent properties of the liquid phase, while the Reynolds number presents a secondary effect. Dimensionless correlations were then obtained to express the turbulent kinetic energy and dissipation rate as a function of these two parameters. Finally, possible applications of the results obtained in this work are presented.

  16. Xenopumice erupted on 15 October 2011 offshore of El Hierro (Canary Islands): a subvolcanic snapshot of magmatic, hydrothermal and pyrometamorphic processes

    Science.gov (United States)

    Del Moro, S.; Di Roberto, A.; Meletlidis, S.; Pompilio, M.; Bertagnini, A.; Agostini, S.; Ridolfi, F.; Renzulli, A.

    2015-06-01

    On 15 October 2011, a submarine eruption offshore of El Hierro Island gave rise to floating volcanic products, known as xenopumices, i.e., pumiceous xenoliths partly mingled and coated with the juvenile basanitic magma. Over the last few years, no consensus in the scientific community in explaining the origin of these products has been reached. In order to better understand the formation of xenopumice, we present a textural, mineralogical, and geochemical study of the possible magmatic, hydrothermal, and pyrometamorphic processes, which usually operate in the plumbing systems of active volcanoes. We carried out a comprehensive SEM investigation and Sr-Nd-Pb isotope analyses on some samples representative of three different xenopumice facies. All the data were compared with previous studies, new data for El Hierro extrusives and a literature dataset of Canary Islands igneous and sedimentary rocks. In the investigated xenopumices, we emphasize the presence of restitic magmatic phases as well as crystallization of minerals (mainly olivine + pyroxene + magnetite aggregates) as pseudomorphs after pre-existing mafic phenocrysts, providing evidence of pyrometamorphism induced by the high-T juvenile basanitic magma. In addition, we identify veins consisting of zircon + REE-oxides + mullite associated with Si-rich glass and hydrothermal quartz, which indicate the fundamental role played by hydrothermal fluid circulation in the xenopumice protolith. The petrological data agree with a pre-syneruptive formation of the xenopumice, when El Hierro basanite magma intruded hydrothermally altered trachyandesite to trachyte rocks and triggered local partial melting. Therefore, the El Hierro xenopumice represents a snapshot of the transient processes at the magma-wall rock interface, which normally occurs in the feeding system of active volcanoes.

  17. On the detection of thermohygrometric differences of Juniperus turbinata habitat between north and south faces in the island of El Hierro (Canary Islands)

    Science.gov (United States)

    Salva-Catarineu, Montserrat; Salvador-Franch, Ferran; Lopez-Bustins, Joan A.; Padrón-Padrón, Pedro A.; Cortés-Lucas, Amparo

    2016-04-01

    The current extent of Juniperus turbinata in the island of El Hierro is very small due to heavy exploitation for centuries. The recovery of its natural habitat has such a high environmental and scenic interest since this is a protected species in Europe. The study of the environmental factors that help or limit its recovery is indispensable. Our research project (JUNITUR) studied the populations of juniper woodlands in El Hierro from different environments. These environments are mainly determined by their altitude and exposure to north-easterly trade winds. The main objective of this study was to compare the thermohygrometric conditions of three juniper woodlands: La Dehesa (north-west face at 528 m a.s.l.), El Julan (south face at 996 m a.s.l.) and Sabinosa (north face at 258 m a.s.l.). They are located at different altitude and orientation in El Hierro and present different recovery rates. We used air sensor data loggers fixed to tree branches for recording hourly temperature and humidity data in the three study areas. We analysed daily data of three annual cycles (from September 2012 to August 2015). Similar thermohygrometric annual cycles among the three study areas were observed. We detected the largest differences in winter temperature and summer humidity between the north (to windward) (Sabinosa and La Dehesa) and south (to leeward) (El Julan) faces of the island. The juniper woodland with a highest recovery rate (El Julan) showed the most extreme temperature conditions in both winter and summer seasons. The results of this project might contribute to the knowledge of the juniper bioclimatology in El Hierro, where there is the biggest population of Juniperus turbinata throughout the Canary Islands.

  18. HIERRO ELEMENTAL PARA REMOCIÓN DE NÍQUEL, COMÚNMENTE ENCONTRADO EN DRENAJE ÁCIDO DE MINAS

    Directory of Open Access Journals (Sweden)

    Maria A. Liendo

    2011-01-01

    Full Text Available El objetivo de este estudio fue evaluar la remoción del Ni2+ con partículas de hierro comercial, pues este catión se encuentra frecuentemente en los drenajes ácidos de minas (DAM, que es uno de los problemas ambientales más serios en la industria minera que afecta fuentes de aguas naturales. Fueron realizados ensayos en laboratorio con hierro comercial y soluciones sintéticas que contienen Ni2+, para observar tanto la cinética de remoción como los datos de equilibrio. Los resultados, mostraron que estos siguen el modelo de la isoterma de adsorción de Langmuir y que los datos cinéticos se ajustaron con la ecuación del modelo de adsorción de pseudo segundo orden. Se concluye del presente estudio que la remoción de níquel con hierro en estado elemental (HEE es posible y ocurre de manera rápida.

  19. Diffuse H_{2} emission: a useful geochemical tool to monitor the volcanic activity at El Hierro volcano system

    Science.gov (United States)

    Pérez, Nemesio M.; Melián, Gladys; González-Santana, Judit; Barrancos, José; Padilla, Germán; Rodríguez, Fátima; Padrón, Eleazar; Hernández, Pedro A.

    2016-04-01

    The occurrence of interfering processes affecting reactive gases as CO2 during its ascent from magmatic bodies or hydrothermal systems toward the surface environment hinders the interpretation of their enrichments in the soil atmosphere and fluxes for volcano monitoring purposes (Marini and Gambardella, 2005). These processes include gas scrubbing by ground-waters and interaction with rocks, decarbonatation processes, biogenic production, etc. Within the rest of the soil gases, particularly interest has been addressed to light and highly mobile gases. They offer important advantages for the detection of vertical permeability structures, because their interaction with the surrounding rocks or fluids during the ascent toward the surface is minimum. H2 is one of the most abundant trace species in volcano-hydrothermal systems and is a key participant in many redox reactions occurring in the hydrothermal reservoir gas (Giggenbach, 1987). Although H2 can be produced in soils by N2-fixing and fertilizing bacteria, soils are considered nowadays as sinks of molecular hydrogen (Smith-Downey et al., 2006). Because of its chemical and physical characteristics, H2 generated within the crust moves rapidly and escapes to the atmosphere. These characteristics make H2 one of the best geochemical indicators of magmatic and geothermal activity at depth. El Hierro is the youngest and the SW-most of the Canary Islands and the scenario of the last volcanic eruption of the archipelago, a submarine eruption that took place 2 km off the southern coast of the island from October 2011 to March 2012. Since at El Hierro Island there are not any surface geothermal manifestations (fumaroles, etc), we have focused our studies on soil degassing surveys. Here we show the results of soil H2 emission surveys that have been carried out regularly since mid-2012. Soil gas samples were collected in ˜600 sites selected based on their accessibility and geological criteria. Soil gases were sampled at ˜40

  20. The 2011 El Hierro submarine eruption: estimation of erupted lava flow volume on the basis of helicopter thermal surveys

    Science.gov (United States)

    Hernández, P. A.; Calvari, S.; Calvo, D.; Marquez, A.; Padron, E.; Pérez, N.; Melian, G.; Padilla, G.; Barrancos, J.; Dionis, S.; Rodríguez, F.; Nolasco, D.; Hernández, I.

    2012-04-01

    El Hierro represents the summit of a volcanic shield elevating from the surrounding seafloor at depth of 4000 m to up to 1501 m above sea level. The island is believed to be near the present hotspot location in the Canaries with the oldest subaerial rocks dated at 1.12 Ma. The subaerial parts of the El Hierro rift zones (NE, NW and S Ridges) are characterized by tightly aligned dyke complexes with clusters of cinder cones as their surface expressions. Since 16 July, an anomalous seismicity at El Hierro Island was recorded by IGN seismic network. After the occurrence of more than 10,000 seismic events, volcanic tremor started at 05:15 on 10 October, followed on the afternoon of 12 October by a green discolouration of seawater, strong bubbling and degassing, and abundant bombs on a decimetre scale found floating on the ocean surface offshore, southwest of La Restinga village. The Canary Government raised the alert level from green to yellow on 10 October (3 colour basis: green, yellow, and red). Further episodes have occurred during November, December 2011 and January 2012, with turbulent water, foam rings, and volcanic material again reaching the sea surface. Colour of the discoloured area has changed frequently from light green to dark brown, depending on the eruptive activity. During the whole eruptive period, The Volcanological Institute of Canary Islands and the Helicopter Unit of the Spanish Civil Guard have carried out regularly thermal surveys with a hand held FLIR Thermal Camera P65. The images have been collected taking care of avoiding solar reflection (with cloudy weather) or at times of the day without direct sun light. Air temperature and humidity were measured with a handled thermo-hygrometer every time before the thermal image collection, and measurements were always performed at two fixed heights: 2000 and 1000 feet, and images were collected as perpendicular as possible to the surface. Together with thermal images, digital photos of the surface have

  1. La erupción submarina de La Restinga en la isla de El Hierro, Canarias: Octubre 2011-Marzo 2012

    Directory of Open Access Journals (Sweden)

    Perez-Torrado, F. J.

    2012-06-01

    Full Text Available The first signs of renewed volcanic activity at El Hierro began in July 2011 with the occurrence of abundant, low-magnitude earthquakes. The increasing seismicity culminated on October 10, 2011, with the onset of a submarine eruption about 2 km offshore from La Restinga, the southernmost village on El Hierro. The analysis of seismic and deformation records prior to, and throughout, the eruption allowed the reconstruction of its main phases: 1 ascent of magma and migration of hypocentres from beneath the northern coast (El Golfo towards the south rift zone, close to La Restinga, probably marking the hydraulic fracturing and the opening of the eruptive conduit; and 2 onset and development of a volcanic eruption indicated by sustained and prolonged harmonic tremor whose intensity varied with time. The features monitored during the eruption include location, depth and morphological evolution of the eruptive source and emission of floating volcanic bombs. These bombs initially showed white, vesiculated cores (originated by partial melting of underlying pre-volcanic sediments upon which the island of El Hierro was constructed and black basanite rims, and later exclusively hollow basanitic lava balloons. The eruptive products have been matched with a fissural submarine eruption without ever having attained surtseyan explosiveness. The eruption has been active for about five months and ended in March 2012, thus becoming the second longest reported historical eruption in the Canary Islands after the Timanfaya eruption in Lanzarote (1730-1736. This eruption provided the first opportunity in 40 years to manage a volcanic crisis in the Canary Islands and to assess the interpretations and decisions taken, thereby gaining experience for improved management of future volcanic activity. Seismicity and deformation during the eruption were recorded and analysed by the Instituto Geográfico Nacional (IGN. Unfortunately, a lack of systematic sampling of erupted

  2. Migración de hierro y níquel, y estabilidad oxidativa del aceite refinado de soja calentado en utensilios culinarios de diversos materiales

    Directory of Open Access Journals (Sweden)

    Almeyda Haj-Isa, Niurka Maritza

    2007-12-01

    Full Text Available Cookware may release some inorganic components into foods during cooking, some of which have undesirable consequences. In fried foods, for instance, oil oxidation is favored by metals. The present study evaluated oxidative stability (AOCS method and iron and nickel migration (inductively coupled plasma-optical emission spectrometry into refined soybean oil in four cycles, with intervals of 24 hours. The cookware materials were glass, aluminum, stainless steel, iron and soapstone. The results demonstrated that the lowest metal migration occurred from glass and aluminum pans while the oil heated in these pans showed the highest oxidative stability. The highest migration of Fe and Ni into the oil occurred from the soapstone and iron pots (3.94 and 3.21 mg _ kg-1, respectively.Nevertheless, increasing loss of oxidative stability was evident in the oils heated in the soapstone, stainless steel and iron cookware, in this order. Since iron migration was lower from glass and aluminum pans, these were considered the best type of materials for fryingDurante la elaboración de alimentos los utensilios culinarios pueden liberar componentes inorgánicos ocasionalmente no deseables. La oxidación del aceite es durante la fritura es favorecida por la presencia de metales. Fue evaluada la migración de hierro y níquel (espectrometría de emisión óptica y la estabilidad oxidativa (método AOCS del aceite de soja sometido a cuatro calentamientos con intervalos de 24 horas en cazuelas de vidrio, aluminio, acero inoxidable, hierro y piedra-jabón. La mayor migración de hierro al aceite ocurrió en las cazuelas de hierro (3,94 mg•kg–1 y piedra (3,21 mg _ kg–1, sin diferencia estadística entre ellas. La pérdida progresiva de estabilidad oxidativa fue acentuada en los aceites calentados en utensilios de piedra, acero inoxidable e hierro, en tal orden. Vidrio y aluminio fueron considerados los mejores materiales para la fabricación de cazuelas

  3. Efecto de adición de iones hierro y zinc sobre la producción de etanol de dos cepas recombinantes de Saccharomyces cerevisiae

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    Carolina Peña Serna

    2010-01-01

    Full Text Available La producción de etanol por fermentación es influenciada por la presencia de iones metálicos como hierro y zinc dado que son cofactores de la enzima alcohol deshidrogenasa. El estudio de este efecto permitiría identificar el comportamiento de los microorganismos fermentadores en sustratos industriales que contienen altas concentraciones de este tipo de iones. Este trabajo evaluó la producción de biomasa, los azúcares residuales y la producción de etanol por fermentación de tres cepas de S. cerevisiae, CBS8066, recombinantes GG570-CIBI y GG570-CIBII, bajo el efecto de la adición de hierro a 0, 50 y 150 M, y zinc a 0 y 50 M. Las cepas presentaron inhibición en la producción de biomasa y etanol bajo efecto de iones de hierro y zinc, siendo dicha inhibición mayor al estar en presencia de zinc o alta concentración de hierro. GG570-CIBI mostró disminución en producción de biomasa de 4 g/L y una caída en producción de etanol de 40% en el tratamiento 150 M hierro-50 M zinc (con respecto al tratamiento basal. GG570-CIBII fue la menos afectada con inhibición en la producción de etanol inferior a 11% a las 20 h de fermentación. Adicionalmente, presentó la mayor producción de etanol cuando hubo adición de 150 M Fe con o sin adición de zinc, siendo dicha producción entre un 9 y 14% superior a la de las cepas CBS8066 y GG570-CIBI respectivamente, bajo las mismas condiciones. Posteriormente, GG570-CIBII será evaluada en sustratos industriales debido a su menor inhibición en la producción de etanol, permitiendo así obtener mejores rendimientos.

  4. PREVALENCIA DE LA DEFICIENCIA DE HIERRO EN DONANTES DE SANGRE. REVISIÓN BIBLIOGRÁFICA DEL PERÍODO 2001- 2011

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    Carmen Yulieth Mantilla-Gutiérrez

    2012-01-01

    Full Text Available Fundamentos: La donación de sangre se asocia con disminución de las reservas de hierro de los donantes, lo que puede afectar el desarrollo de sus funciones fisiológicas y al estado general de salud. Estudios previos reportan una gran divergencia en la prevalencia de deficiencia de hierro en dicha población (1% a 62%. El objetivo del trabajo es determinar la prevalencia de deficiencia de hierro en donantes de sangre a partir de una revisión sistemática de la literatura. Métodos: Búsqueda exhaustiva y reproducible de la literatura en 7 bases de datos con base en un protocolo de búsqueda de estudios en 4 idiomas y publicados entre el 2001 y el 2011 con criterios de inclusión, exclusión y extracción de información. El análisis se realizó con base en el cálculo de la prevalencia global y específica por sexo y número de donaciones, con sus respectivos intervalos de confianza, utilizando los programas Excel y Epidat 3.0. Resultados: Se obtuvo una población total de 16.979 donantes, 5.096 de repetición, con una proporción de hombres del 59%. Se halló una prevalencia de deficiencia de hierro del 13% (IC 95% 12,4-13,4, con una rango entre 1% y 62%, siendo estadísticamente significativa la mayor frecuencia en mujeres (19,56% IC 95%: 18,59 - 20,53 y donantes repetidores (20,36% IC 95%: 19,25 - 21,48. Conclusión: Se obtuvo una prevalencia de deficiencia de hierro en donantes de sangre por encima de grupos de mayor riesgo como los niños, siendo mayor en donantes del sexo femenino y de repetición.

  5. Comportamiento del hierro nodular austemperizado en condiciones de corrosión y desgaste // Behavior of austempered ductile iron under wear and corrosion conditions

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    L. Goyos Pérez

    1999-07-01

    Full Text Available Los hierros nodulares en general y los austemperizados en particular han sido usados con cada vez mayor frecuencia debido asus relevantes propiedades mecánicas en comparación con su costo.En el presente trabajo se valora el comportamiento del hierro nodular ante el trabajo en condiciones de desgaste y corrosión,luego de ser sometido a diferentes tratamientos de austemperizado.Fueron usados un hierro nodular aleado con níquel y molibdeno y otro no aleado. Ambos hierros fueron sometidos a diferentestratamientos de austemperización con mantenimientos isotérmicos a temperaturas entre 250°C y 425°C por tiempos entre 15 y180 minutos.Las muestras tratadas fueron sometidas a ensayos de desgaste por fricción en condiciones no lubricadas determinando laspendientes de desgaste uniforme para cada caso. La resistencia a la corrosión fue determinada mediante el métodopotenciométrico usando como medio el jugo de caña sintético.A partir de los resultados obtenidos se valora la influencia de los diferentes tratamientos sobre las propiedades estudiadas y sedeterminan los más efectivos desde el punto de vista técnico económico.Palabras claves: Hierro nodular, corrosión, desgaste, austemperizado.____________________________________________________________________________AbstractNodular irons and particularly austempered ductile iron has been used more and more due to their excellent mechanicalproperties in comparison with their cost.Presently work deals on behavior of nodular iron working under wear and corrosion conditions, after being submitted todifferent austempered treatments.A nodular iron alloyed with nickel and molybdenum were used as well as a not alloyed one. Both irons were treated underdifferent austempered treatment combinations using isothermal maintenance to temperatures between 250°C and 425°C andspending times between 15 and 180 minutes.Samples were submitted to non-lubricated wear using a “pin on disk” method evaluating the

  6. Estado de nutrición en hierro en una población de 4 a 14 años, urbano marginal, de Lima

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    Alicia Fernández

    2007-06-01

    Full Text Available Objetivo: Determinar el estado de nutrición en hierro en una población de 4 a 14 años. Diseño: Estudio descriptivo, observacional, transversal y prospectivo. Lugar: Facultad de Medicina, Universidad Nacional Mayor de San Marcos. Participantes: Niños, entre 4 y 14 años. Intervenciones: Se estudió 349 niños, 170 de sexo masculino y 179 de sexo femenino, entre 4 y 14 años de edad, del Centro de Salud San Genaro de Villa, Chorrillos, entre setiembre 2001 y agosto 2002. Principales medidas de resultados: Estado de nutrición en hierro. Resultados: El 68,8% (240 no presentó alteración en el estado de nutrición en hierro (ENH, frente a 31,2% (109 que sí lo presentó. De los 109 niños con alteración en el ENH, 68,8% (75 clasificó en el estadio I de depleción latente (ferritina 400 ug/dL, y 8,3% (9, en el estadio III de anemia ferropénica (hemoglobina <11,5 g/100 mL para menores de 11 años y <12 g/100 mL para 12 a 14 años, hematocrito <34 para menores de 11 años y <36% para 12 a 14 años, volumen corpuscular medio <80 fl, y hemoglobina corpuscular media <27pg. Conclusiones: El alto porcentaje de niños con alteración en el estado de nutrición en hierro, estadio I, identifica a una población en riesgo de anemia ferropénica. Se recomienda que los estudios de deficiencia en hierro se restrinjan a niños en estadio I, con el fin de establecer políticas de participación ciudadana y establecer alianzas sectoriales y extrasectoriales (sector educación, para la promoción de la nutrición infantil.

  7. Estudio de la reoxidación y carburización de pelets reducidos de mineral de hierro

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    Lemus R., J.

    1998-12-01

    Full Text Available The influence of carburization on the reoxidation of commercial iron ore pellets was studied. The pellets were H2-reduced up to 88 % and then carburized in H2/CO/CO2 gas mixture, for 0, 12, 18, 25 and 32 min, at 700, 800, 900 and 1000°C. After the reduction-carburization process, the pellets were reoxidized at 250, 300, 350 and 400°C. It was found out that the higher reduction temperature, the lower was the reoxidation degree. This effect was stronger at the reoxidation temperatures of 250 and 300°C. The presence of iron carbide (Fe3C was more notorious when the reduction was carried out at 700 and 800°C, and the carburization time was increased. Finally, it was observed that the higher the reoxidation temperature, the higher was the reoxidation degree.

    Se estudió la influencia de la carburización en la reoxidación de pelets de mineral de hierro de grado comercial. Los pelets fueron reducidos en hidrógeno hasta un 88 % y carburizados en una mezcla de gas H2-CO-CO2, por 0, 12, 18, 25 y 32 min a 700, 800, 900 y 1000°C. Después del proceso de reducción-carburización, los pelets se reoxidaron a 250, 300, 350 y 400°C. Se encontró que el grado de reoxidación disminuye con el incremento de la temperatura de reducción. Este efecto es más marcado a las temperaturas de reoxidación de 250°C y 300°C. La presencia de carburo de hierro (Fe3C fue más clara al incrementarse el tiempo de carburización cuando la reducción se llevó a cabo a 700 y 800°C. Finalmente, se observó que el grado de reoxidación es mayor a medida que se incrementa la temperatura de reoxidación .

  8. Emissions of Fe(II) and its kinetic of oxidation at Tagoro submarine volcano, El Hierro (Canary Islands)

    Science.gov (United States)

    González-Dávila, M.; Santana-González, C.; Santana-Casiano, J. M.

    2017-12-01

    The eruptive process that took place in October 2011 in the submarine volcano Tagoro off the Island of El Hierro (Canary Island) and the subsequent degasification stage, five months later, have increased the concentration of TdFe(II) (Total dissolved iron(II)) in the waters nearest to the volcanic edifice. In order to detect any variation in concentrations of TdFe(II) due to hydrothermal emissions, three cruises were carried out two years after the eruptive process in October 2013, March 2014, May 2015, March 2016 and November 2016. The results from these cruises confirmed important positive anomalies in TdFe(II), which coincided with negatives anomalies in pHF,is (pH in free scale, at in situ conditions) located in the proximity of the main cone. Maximum values in TdFe(II) both at the surface, associated to chlorophyll a maximum, and at the sea bottom, were also observed, showing the important influence of organic complexation and particle re-suspension processes. Temporal variability studies were carried out over periods ranging from hours to days in the stations located over the main and two secondary cones in the volcanic edifice with positive anomalies in TdFe(II) concentrations and negative anomalies in pHF,is values. Observations showed an important variability in both pHF,is and TdFe(II) concentrations, which indicated the volcanic area was affected by a degasification process that remained in the volcano after the eruptive phase had ceased. Fe(II) oxidation kinetic studies were also undertaken in order to analyze the effects of the seawater properties in the proximities of the volcano on the oxidation rate constants and t1/2 (half-life time) of ferrous iron. The increased TdFe(II) concentrations and the low associated pHF,is values acted as an important fertilization event in the seawater around the Tagoro volcano at the Island of El Hierro providing optimal conditions for the regeneration of the area.

  9. Development and recent activity of the San Andrés landslide on El Hierro, Canary Islands, Spain

    Science.gov (United States)

    Klimeš, Jan; Yepes, Jorge; Becerril, Laura; Kusák, Michal; Galindo, Inés; Blahut, Jan

    2016-05-01

    Extremely voluminous landslides with a long run-out (also known as megalandslides) on oceanic volcanic islands are infrequent denudational processes on such islands. At the same time, they represent a major geological hazard that must be looked into to avoid negative consequences for the inhabitants of these islands. Their occurrence can be related to periods of intense seismo-volcanic activity, similar to that which occurred on El Hierro Island over 2011-2012. Landslides on volcanic islands are studied using onshore and offshore geological, geophysical and geomorphological records, considering their unique triggering conditions (e.g. lava intrusions, eruptive vents, magma chamber collapses). Previous work has pointed out similarities between specific cases of landslides on volcanic islands and deep-seated gravitational slope deformations (DSGSDs) which are typical in high mountain settings. Nevertheless, the methodological approaches and concepts used to investigate DSGSDs are not commonly applied on volcanic islands studies, even though their use may provide new information about the development stage, recent movements and future hazards. Therefore, this approach for studying the San Andrés landslide (SAL) on El Hierro (Canary Islands) has been developed applying a detailed morphological field mapping, an interpretation of digital elevation models, structural measurements, kinematic testing, and a precise movement monitoring system. The acquired information revealed a strong structural influence on the landslide morphology and the presence of sets of weakened planes acting as the sliding surfaces of the SAL or secondary landslides within its body. The presence of secondary landslides, deep erosive gullies, coastal cliffs and high on-shore relative relief also suggests a high susceptibility to future landslide movement. Direct monitoring on the landslide scarps and the slip plane, performed between February 2013 and July 2014, using an automated optical

  10. Deployment of a seismic array for volcano monitoring during the ongoing submarine eruption at El Hierro, Canary Islands

    Science.gov (United States)

    Abella, R.; Almendros, J.; Carmona, E.; Martin, R.

    2012-04-01

    On 17 July 2011 there was an important increase of the seismic activity at El Hierro (Canary Islands, Spain). This increase was detected by the Volcano Monitoring Network (Spanish national seismic network) run by the Instituto Geográfico Nacional (IGN). As a consequence, the IGN immediately deployed a dense, complete monitoring network that included seismometers, GPS stations, geochemical equipment, magnetometers, and gravity meters. During the first three months of activity, the seismic network recorded over ten thousand volcano-tectonic earthquakes, with a maximum magnitude of 4.6. On 10 October 2011 an intense volcanic tremor started. It was a monochromatic signal, with variable amplitude and frequency content centered at about 1-2 Hz. The tremor onset was correlated with the initial stages of the submarine eruption that occurred from a vent located south of El Hierro island, near the village of La Restinga. At that point the IGN, in collaboration with the Instituto Andaluz de Geofísica, deployed a seismic array intended for volcanic tremor monitoring and analysis. The seismic array is located about 7 km NW of the submarine vent. It has a 12-channel, 24-bit data acquisition system sampling each channel at 100 sps. The array is composed by 1 three-component and 9 vertical-component seismometers, distributed in a flat area with an aperture of 360 m. The data provided by the seismic array are going to be processed using two different approaches: (1) near-real-time, to produce information that can be useful in the management of the volcanic crisis; and (2) detailed investigations, to study the volcanic tremor characteristics and relate them to the eruption dynamics. At this stage we are mostly dedicated to produce fast, near-real-time estimates. Preliminary results have been obtained using the maximum average cross-correlation method. They indicate that the tremor wavefronts are highly coherent among array stations and propagate across the seismic array with an

  11. Relación entre las reservas de hierro maternas y del recién nacido Relationship between maternal and neonatal iron stores

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    María Eugenia Vásquez-Molina

    2001-10-01

    Full Text Available Objetivo. Determinar la relación de los valores hematológicos maternos y neonatales en casos de reservas maternas de hierro bajas, moderadas y normales. Material y métodos. Diseño transversal en el que se incluyó a 163 mujeres embarazadas y sus neonatos de término, derechohabientes del Hospital de Ginecología y Obstetricia número 15 del Instituto Mexicano del Seguro Social (IMSS en Chihuahua, Chih., México. Se analizaron antecedentes maternos. Se determinaron niveles de hemoglobina, hematocrito y ferritina sérica en muestras maternas y de cordón umbilical. Se definieron reservas de hierro maternas de acuerdo a ferritina (µg /l: bajas o = 20.1. Se utilizó la prueba de Kruskal Wallis para establecer diferencias entre grupos, ji cuadrada para diferencia de proporciones y r de Pearson para establecer la relación entre reservas de hierro maternas y del recién nacido. Resultados. Se determinó una débil correlación entre la ferritina materna y neonatal r=0.14 (p=0.07. Las medias geométricas de ferritina neonatal respecto a las reservas maternas bajas, moderadas y normales fue de 4.77, 4.85 y 5.02, respectivamente (p=0.12. Las reservas de hierro maternas se modificaron con el suplemento de hierro (p=0.01. Conclusiones. Las reservas de hierro en el recién nacido están en estrecha relación con las maternas. Las mujeres que toman suplementos con hierro durante la gestación tienen reservas mayores al final del embarazo. El texto completo en inglés de este artículo está disponible en: http://www.insp.mx/salud/index.htmlObjective. To establish the relationship of normal, low, and moderate blood iron values in mothers and their newborns. Material and Methods. A cross-sectional study was conducted among 163 pregnant women and their newborns, users of Hospital de Ginecología y Obstetricia número 15, Instituto Mexicano del Seguro Social, from Chihuahua, Mexico. The mothers' clinical histories were collected and analyzed; hemoglobin

  12. Managing iron deficiency and iron deficiency anemia in inflammatory bowel disease. The results of the "Gestiona hierro-EII" survey.

    Science.gov (United States)

    Casellas Jordá, Francesc; Vera Mendoza, Isabel; Barreiro-de Acosta, Manuel; Vázquez Morón, Juan María; López Román, Javier; Júdez Gutiérrez, Javier

    2018-03-01

    iron deficiency anemia is a common and very relevant manifestation of inflammatory bowel disease (IBD). Although clinical practice guidelines have been published and updated on this subject, the management in the daily practice of this complication is far from optimal. to determine the actual management, needs and limitations of anemia in IBD by means of a survey of gastroenterology specialists. a self-administered telematic survey was carried out between April and May 2017 and was sent to SEPD members. The survey included four sections: participant demographics, monitoring, treatment and limitations/needs. a total of 122 evaluable surveys were received from all Spanish autonomous communities. Iron deficiency anemia is considered as a frequent manifestation of IBD and is monitored in all patients via the measurement of hemoglobin and ferritin. In the case of anemia, the survey respondents found it necessary to rule out the presence of IBD activity. However, only 14.8% prescribed intravenous iron when IBD was active. The required dose of intravenous iron is mainly calculated according to patient needs but only 33.1% of clinicians infused doses of 1 g or more. the "Gestiona Hierro EII" survey on the management of anemia in IBD demonstrated a high quality of care, even though some aspects need to be improved. These included the prescription of intravenous iron for patients with disease activity, the use of high-dose intravenous iron and the implementation of algorithms into clinical practice.

  13. A new Volcanic managEment Risk Database desIgn (VERDI): Application to El Hierro Island (Canary Islands)

    Science.gov (United States)

    Bartolini, S.; Becerril, L.; Martí, J.

    2014-11-01

    One of the most important issues in modern volcanology is the assessment of volcanic risk, which will depend - among other factors - on both the quantity and quality of the available data and an optimum storage mechanism. This will require the design of purpose-built databases that take into account data format and availability and afford easy data storage and sharing, and will provide for a more complete risk assessment that combines different analyses but avoids any duplication of information. Data contained in any such database should facilitate spatial and temporal analysis that will (1) produce probabilistic hazard models for future vent opening, (2) simulate volcanic hazards and (3) assess their socio-economic impact. We describe the design of a new spatial database structure, VERDI (Volcanic managEment Risk Database desIgn), which allows different types of data, including geological, volcanological, meteorological, monitoring and socio-economic information, to be manipulated, organized and managed. The root of the question is to ensure that VERDI will serve as a tool for connecting different kinds of data sources, GIS platforms and modeling applications. We present an overview of the database design, its components and the attributes that play an important role in the database model. The potential of the VERDI structure and the possibilities it offers in regard to data organization are here shown through its application on El Hierro (Canary Islands). The VERDI database will provide scientists and decision makers with a useful tool that will assist to conduct volcanic risk assessment and management.

  14. Different deformation patterns using GPS in the volcanic process of El Hierro (Canary Island) 2011-2013

    Science.gov (United States)

    García-Cañada, Laura; José García-Arias, María; Pereda de Pablo, Jorge; Lamolda, Héctor; López, Carmen

    2014-05-01

    Ground deformation is one of the most important parameter in volcano monitoring. The detected deformations in volcanic areas can be precursors of a volcanic activity and contribute with useful information to study the evolution of an unrest, eruption or any volcanic process. GPS is the most common technique used to measure volcano deformations. It can be used to detect slow displacement rates or much larger and faster deformations associated with any volcanic process. In volcanoes the deformation is expected to be a mixed of nature; during periods of quiescence it will be slow or not present, while increased activity slow displacement rates can be detected or much larger and faster deformations can be measure due to magma intrusion, for example in the hours to days prior a eruption beginning. In response to the anomalous seismicity detected at El Hierro in July 2011, the Instituto Geográfico Nacional (IGN) improved its volcano monitoring network in the island with continuous GPS that had been used to measure the ground deformation associated with the precursory unrest since summer 2011, submarine eruption (October 2011-March 2012) and the following unrest periods (2012-2013). The continuous GPS time series, together with other techniques, had been used to evaluate the activity and to detect changes in the process. We investigate changes in the direction and module of the deformation obtained by GPS and they show different patterns in every unrest period, very close to the seismicity locations and migrations.

  15. VISIÓN ESTRATÉGICA DE LA INDUSTRIA MINERA DE HIERRO Y EL ACERO DE VENEZUELA

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    Juan Enrique Villalva A.

    2016-04-01

    Full Text Available El propósito de este estudio fue primero, determinar el resultado de la visión estratégica aplicada a industria minera de hierro y el acero de Venezuela y segundo, la construcción de la visión estratégica de estas industrias de acuerdo a las actuales realidades. Para ello, primero se revisó la evolución de la visión estratégica de ambas industrias y sus resultados. Segundo, se revisó la situación actual, identificando las principales características del entorno externo e interno, sus capacidades, limitaciones y situación económico – financiera, que afectan sus opciones y oportunidades estratégicas. El estudio concluye que ambas industrias han presentado resultados precarios desde 2006, en cuanto a producción, productividad, tasa de uso de la capacidad instalada y margen de utilidad, producto de un cambio radical en la visión estratégica. Finalmente se obtienen los lineamientos de la visión estratégica, como imagen a futuro de ambas industrias, como un aporte para mejorar estas importantes industrias.

  16. Beauveria bassiana (Bals. Vuill. spores production in biphasic process utilizing different liquid media/ Produção de esporos de Beauveria bassiana (Bals. Vuill. num processo bifásico utilizando diferentes meios líquidos

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    Janaína Zorzetti

    2005-06-01

    Full Text Available Entomopathogenic production techniques are developed with the objective of increasing productivity and reducing costs of the process. The objective of this study was to evaluate Beauveria bassiana biomass production in liquid media and conidiogenesis in a biphasic process. The liquid media were: CF (crysalid flour, PD (potato dextrose and CFPD (crysalid flour+potato+dextrose. The evaluation periods for biomass production were: 24, 48, 72, 96, 120 and 144 hours. For production by biphasic process different quantities of liquid media (5, 10, 15 and 20 mL with different incubation periods (24, 48 and 72 hours, were added on the pre-cooked rice (200 g with conidia production evaluation after 10 days. CFPD media was the most productive biomass in all evaluated periods. In the biphasic process, bigger conidia production were attained when it was utilized fungi biomass produced in CF and CFPD (2.7 x 1012 and 2.8 x 1012 conidia/g of rice for rice inoculation. The quantities of 5, 15, 20 mL of liquid media, inoculated on the rice were not statistically different. The incubation periods of 24 and 48 hours of the fungus in the liquid media, gave bigger cionidiogenesis then 72 hours. The data show the necessity of carbon and nitrogen for biomass production in the liquid media and for conidiogenesis in the solid media. Also with these informations it was possible to optimize the biphasic process, adding 5 mL of the liquid media CFPD on the rice (200 g with 24 hours of incubation.Técnicas de produção de fungos entomopatogênicos são desenvolvidas buscando aumentar a produtividade desses patógenos e reduzir custos do processo. O objetivo deste trabalho foi avaliar a produção de biomassa de Beauveria bassiana em meios líquidos e a conidiogênese no processo bifásico. Os meios líquidos testados foram: FC (farinha de crisálida, BD (batata+dextrose e FCBD (farinha de crisálida+batata+dextrose. Os períodos de avaliação da produção de biomassa foram

  17. Submarine seismic monitoring of El Hierro volcanic eruption with a 3C-geophone string: applying new acquisition and data processing techniques to volcano monitoring

    Science.gov (United States)

    Jurado, Maria Jose; Ripepe, Maurizio; Lopez, Carmen; Blanco, Maria Jose; Crespo, Jose

    2015-04-01

    A submarine volcanic eruption took place near the southernmost emerged land of the El Hierro Island (Canary Islands, Spain), from October 2011 to February 2012. The Instituto Geografico Nacional (IGN) seismic stations network evidenced seismic unrest since July 2011 and was a reference also to follow the evolution of the seismic activity associated with the volcanic eruption. Right after the eruption onset, in October 2011 a geophone string was deployed by the CSIC-IGN to monitor seismic activity. Monitoring with the seismic array continued till May 2012. The array was installed less than 2 km away from the new vol¬cano, next to La Restinga village shore in the harbor from 6 to 12m deep into the water. Our purpose was to record seismic activity related to the volcanic activity, continuously and with special interest on high frequency events. The seismic array was endowed with 8, high frequency, 3 component, 250 Hz, geophone cable string with a separation of 6 m between them. Each geophone consists on a 3-component module based on 3 orthogonal independent sensors that measures ground velocity. Some of the geophones were placed directly on the seabed, some were buried. Due to different factors, as the irregular characteristics of the seafloor. The data was recorded on the surface with a seismometer and stored on a laptop computer. We show how acoustic data collected underwater show a great correlation with the seismic data recorded on land. Finally we compare our data analysis results with the observed sea surface activity (ash and lava emission and degassing). This evidence is disclosing new and innovative tecniques on monitoring submarine volcanic activity. Reference Instituto Geográfico Nacional (IGN), "Serie El Hierro." Internet: http://www.ign.es/ign/resources /volcanologia/HIERRO.html [May, 17. 2013

  18. Seismic hydraulic fracture migration originated by successive deep magma pulses: The 2011-2013 seismic series associated to the volcanic activity of El Hierro Island

    Science.gov (United States)

    Díaz-Moreno, A.; Ibáñez, J. M.; De Angelis, S.; García-Yeguas, A.; Prudencio, J.; Morales, J.; Tuvè, T.; García, L.

    2015-11-01

    In this manuscript we present a new interpretation of the seismic series that accompanied eruptive activity off the coast of El Hierro, Canary Islands, during 2011-2013. We estimated temporal variations of the Gutenberg-Richter b value throughout the period of analysis, and performed high-precision relocations of the preeruptive and syneruptive seismicity using a realistic 3-D velocity model. Our results suggest that eruptive activity and the accompanying seismicity were caused by repeated injections of magma from the mantle into the lower crust. These magma pulses occurred within a small and well-defined volume resulting in the emplacement of fresh magma along the crust-mantle boundary underneath El Hierro. We analyzed the distribution of earthquake hypocenters in time and space in order to assess seismic diffusivity in the lower crust. Our results suggest that very high earthquake rates underneath El Hierro represent the response of a stable lower crust to stress perturbations with pulsatory character, linked to the injection of magma from the mantle. Magma input from depth caused large stress perturbations to propagate into the lower crust generating energetic seismic swarms. The absence of any preferential alignment in the spatial pattern of seismicity reinforces our hypothesis that stress perturbation and related seismicity, had diffusive character. We conclude that the temporal and spatial evolution of seismicity was neither tracking the path of magma migration nor it defines the boundaries of magma storage volumes such as a midcrustal sill. Our conceptual model considers pulsatory magma injection from the upper mantle and its propagation along the Moho. We suggest, within this framework, that the spatial and temporal distributions of earthquake hypocenters reflect hydraulic fracturing processes associated with stress propagation due to magma movement.

  19. Precursory diffuse CO2 and H2S emission signatures of the 2011-2012 El Hierro submarine eruption, Canary Islands

    Science.gov (United States)

    Pérez, Nemesio M.; Padilla, Germán D.; Padrón, Eleazar; Hernández, Pedro A.; Melián, Gladys V.; Barrancos, José; Dionis, Samara; Nolasco, Dácil; Rodríguez, Fátima; Calvo, David; Hernández, Íñigo

    2012-08-01

    On October 12, 2011, a submarine eruption began 2 km off the coast of La Restinga, south of El Hierro Island. CO2 and H2S soil efflux were continuously measured during the period of volcanic unrest by using the accumulation chamber method at two different geochemical stations, HIE01 and HIE07. Recorded CO2 and H2S effluxes showed precursory signals that preceded the submarine eruption. Beginning in late August, the CO2 efflux time series started increasing at a relatively constant rate over one month, reaching a maximum of 19 gm-2d-1 one week before the onset of the submarine volcanic eruption. The H2S efflux time series at HIE07 showed a pulse in H2S emission just one day before the initiation of the submarine eruption, reaching peak values of 42 mg m-2 d-1, 10 times the average H2S efflux recorded during the observation period. Since CO2 and H2S effluxes are strongly influenced by external factors, we applied a multiple regression analysis to remove their contribution. A statistical analysis showed that the long-term trend of the filtered data is well correlated with the seismic energy. We find that these geochemical stations are important monitoring sites for evaluating the volcanic activity of El Hierro and that they demonstrate the potential of applying continuous monitoring of soil CO2 and H2S efflux to improve and optimize the detection of early warning signals of future volcanic unrest episodes at El Hierro. Continuous diffuse degassing studies would likely prove useful for monitoring other volcanoes during unrest episodes.

  20. Contenido de ß-caroteno, hierro y zinc en genotipos de camote (Ipomoea batatas L.) durante el almacenamiento, cocción y elaboración de pan

    OpenAIRE

    Carpio Ramos, Rosmery Violeta

    2016-01-01

    Universidad Nacional Agraria La Molina. Escuela de Posgrado. Maestría en Tecnología de Alimentos El camote es uno de los alimentos básicos que han sido asignados para combatir la deficiencia de micronutrientes en especial la deficiencia de vitamina A, hierro y zinc. El presente estudio pretende contribuir con la selección de genotipos para el mejoramiento de la calidad nutricional del camote principalmente en el contenido de β-caroteno, materia seca, hierro y zinc, ayudando a reducir los p...

  1. Estudio caso-control de marcadores de estrés oxidativo y metabolismo del hierro plasmático en la enfermedad de Parkinson

    Directory of Open Access Journals (Sweden)

    Larumbe Ilundáin Rosa

    2001-01-01

    Full Text Available Fundamento:- Existe cada vez más evidencia de la implicación de mecanismos de estrés oxidativo en la enfermedad de Parkinson. Se han descrito en la sustancia negra niveles menores de GSH, aumento del depósito de hierro, aumento de los productos derivados de la peroxidación lipídica y alteraciones del complejo I mitocondrial. Sin embargo, son escasos los estudios de niveles de antioxidantes en sangre periférica y de la influencia del consumo de nutrientes en el desarrollo de la enfermedad. Métodos: Se estudia en un grupo de 79 pacientes con enfermedad de Parkinson idiopática y en un grupo control de 107 sujetos, equiparados por edad, sexo y lugar de residencia, los niveles plasmáticos de: Glutatión reducido (GSH, Malonildialdehído (MDA, ácido úrico, tocoferol, b-caroteno, licopeno y diversos parámetros del metabolismo del hierro. Así mismo, se estima el consumo de ciertos antioxidantes a partir de una encuesta dietética. Resultados: Hemos encontrado diferencias significativas (p<=0,001 en los niveles plasmáticos de GSH entre casos (0,10 mmol/ml ± 0,06 y controles (0,29 mmol/ml ± 0,12. De igual modo, los niveles de ácido úrico en plasma fueron más bajos (p<=0,05 en los casos (4,96 mg/ml ± 1,96 que en los controles (5,39 mg/ml±1,13. No hemos encontrado diferencias significativas de los niveles plasmáticos de MDA, tocoferol, b-caroteno y licopeno. Respecto al metabolismo del hierro, en los pacientes con EP encontramos valores de ferritina y de transferrina significativamente mayores que en los controles, con un índice de saturación de la transferrina menor (p<=0,05. El hierro no mostró cambios significativos entre casos y controles. Conclusiones: Los resultados de este estudio apoyan la posible implicación del estrés oxidativo en la patogénesis de la enfermedad de Parkinson y, a la vez, evidencian alteraciones de algunos parámetros en sangre periférica en concordancia con hallazgos conocidos en la sustancia negra.

  2. ESTUDIO CASOS-CONTROL DE MARCADORES DE ESTRÉS OXIDATIVO Y METABOLISMO DEL HIERRO PLASMÁTICO EN LA ENFERMEDAD DE PARKINSON

    Directory of Open Access Journals (Sweden)

    Rosa Larumbe Ilundáin

    2001-01-01

    Full Text Available Fundamento: Existe cada vez m s evidencia de la implicaci n de mecanismos de estr s oxidativo en la enfermedad de Parkinson. Se han descrito en la sustancia negra niveles menores de GSH, aumento del dep sito de hierro, aumento de los productos derivados de la peroxidaci n lip dica y alteraciones del complejo I mitocondrial. Sin embargo, son escasos los estudios de niveles de antioxidantes en sangre perif rica y de la influencia del consumo de nutrientes en el desarrollo de la enfermedad. M todos: Se estudia en un grupo de 79 pacientes con enfermedad de Parkinson idiop tica y en un grupo control de 107 sujetos, equiparados por edad, sexo y lugar de residencia, los niveles plasm ticos de: Glutati n reducido (GSH, Malonildialdeh do (MDA, cido rico, tocoferol, -caroteno, licopeno y diversos par metros del metabolismo del hierro. As mismo, se estima el consumo de ciertos antioxidantes a partir de una encuesta diet tica. Resultados: Hemos encontrado diferencias significativas (p 0,001 en los niveles plasm ticos de GSH entre casos (0,10 mol/ml 0,06 y controles (0,29 mol/ml 0,12. De igual modo, los niveles de cido rico en plasma fueron m s bajos (p 0,05 en los casos (4,96 mg/ml 1,96 que en los controles (5,39 mg/ml 1,13. No hemos encontrado diferencias significativas de los niveles plasm ticos de MDA, tocoferol, -caroteno y licopeno. Respecto al metabolismo del hierro, en los pacientes con EP encontramos valores de ferritina y de transferrina significativamente mayores que en los controles, con un ndice de saturaci n de la transferrina menor (p 0,05. El hierro no mostr cambios significativos entre casos y controles. Conclusiones: Los resultados de este estudio apoyan la posible implicaci n del estr s oxidativo en la patog nesis de la enfermedad de Parkinson y, a la vez, evidencian alteraciones de algunos par metros en sangre perif rica en concordancia con hallazgos conocidos en la sustancia negra.

  3. Anemia y depleción de las reservas de hierro en adolescentes gestantes de una zona urbana y rural del estado Zulia, Venezuela

    OpenAIRE

    Ortega F, Pablo Antonio; Leal M, Jorymar Yoselyn; Chávez, Carlos Javier; Mejías C, Lidia; Chirinos Q, Noraima; Escalona V, Carolina del Pilar

    2012-01-01

    Objetivo: Analizar la prevalencia de anemia y depleción de las reservas corporales de hierro (DRFe) en adolescentes gestantes urbanas (U) y rurales (R). Metodología: Fueron estudiadas 214 adolescentes gestantes (U=100 y R=114), de baja condición socio-económica. Se realizó una evaluación clínica-obstétrica, nutricional y bioquímica. Según recomendaciones de la OMS y el Grupo Consultivo Internacional de Anemia se consideró anemia en gestantes, I y III trimestre Hb≤110g/L, y II trimestre Hb≤105...

  4. Aportaciones a la transición del hiero I al hierro II en el centro de la cuenca del udero

    Directory of Open Access Journals (Sweden)

    Manuel GARCÍA ALONSO

    2009-10-01

    Full Text Available En la diversidad de publicaciones que se ponen al alcance del investigador, y que son referidas a la Edad del Hierro, entendida de una manera amplia, se viene observando, en el manejo terminológico más bien, una serie de cuestiones que quedan latentes entre las diferentes tomas de postura; pero que, salvo excepciones, no dan pie a una discusión o puesta en común de las mismas, y que entendemos son de capital importancia para la zona objeto de la presente comunicación.

  5. Proyecto para la implementación del taller de fundición de hierro y acero PROFUNCA, en el sector de El Descanso Km. 20

    OpenAIRE

    Armijos Rodríguez, Jorge Luis; Ludeña Carrión, Oscar Andrés

    2008-01-01

    DIAGNOSTICO ACTUAL DEL TALLER. PROFUNCA, Productos Fundidos Cañizares, Taller artesanal que se dedica a la fundición de hierro, para la elaboración de poleas, tapas de alcantarillado y rejillas para sumideros, según el pedido del cliente, que con el pasar de los años ha ido aumentando su producción, instalaciones y sus colaboradores… IDENTIFICACIÓN DE PROCESOS PRODUCTIVO Producción por lotes y producción bajo encargo. ANÁLISIS DE SITUACIÓN ACTUAL Mediante el FODA, el taller se ...

  6. Floating stones off El Hierro, Canary Islands: xenoliths of pre-island sedimentary origin in the early products of the October 2011 eruption

    Science.gov (United States)

    Troll, V. R.; Klügel, A.; Longpré, M.-A.; Burchardt, S.; Deegan, F. M.; Carracedo, J. C.; Wiesmaier, S.; Kueppers, U.; Dahren, B.; Blythe, L. S.; Hansteen, T. H.; Freda, C.; Budd, D. A.; Jolis, E. M.; Jonsson, E.; Meade, F. C.; Harris, C.; Berg, S. E.; Mancini, L.; Polacci, M.; Pedroza, K.

    2012-03-01

    A submarine eruption started off the south coast of El Hierro, Canary Islands, on 10 October 2011 and continues at the time of this writing (February 2012). In the first days of the event, peculiar eruption products were found floating on the sea surface, drifting for long distances from the eruption site. These specimens, which have in the meantime been termed "restingolites" (after the close-by village of La Restinga), appeared as black volcanic "bombs" that exhibit cores of white and porous pumice-like material. Since their brief appearance, the nature and origin of these "floating stones" has been vigorously debated among researchers, with important implications for the interpretation of the hazard potential of the ongoing eruption. The "restingolites" have been proposed to be either (i) juvenile high-silica magma (e.g. rhyolite), (ii) remelted magmatic material (trachyte), (iii) altered volcanic rock, or (iv) reheated hyaloclastites or zeolite from the submarine slopes of El Hierro. Here, we provide evidence that supports yet a different conclusion. We have analysed the textures and compositions of representative "restingolites" and compared the results to previous work on similar rocks found in the Canary Islands. Based on their high-silica content, the lack of igneous trace element signatures, the presence of remnant quartz crystals, jasper fragments and carbonate as well as wollastonite (derived from thermal overprint of carbonate) and their relatively high oxygen isotope values, we conclude that "restingolites" are in fact xenoliths from pre-island sedimentary layers that were picked up and heated by the ascending magma, causing them to partially melt and vesiculate. As they are closely resembling pumice in appearance, but are xenolithic in origin, we refer to these rocks as "xeno-pumice". The El Hierro xeno-pumices hence represent messengers from depth that help us to understand the interaction between ascending magma and crustal lithologies beneath the

  7. Floating stones off El Hierro, Canary Islands: xenoliths of pre-island sedimentary origin in the early products of the October 2011 eruption

    Directory of Open Access Journals (Sweden)

    V. R. Troll

    2012-03-01

    Full Text Available A submarine eruption started off the south coast of El Hierro, Canary Islands, on 10 October 2011 and continues at the time of this writing (February 2012. In the first days of the event, peculiar eruption products were found floating on the sea surface, drifting for long distances from the eruption site. These specimens, which have in the meantime been termed "restingolites" (after the close-by village of La Restinga, appeared as black volcanic "bombs" that exhibit cores of white and porous pumice-like material. Since their brief appearance, the nature and origin of these "floating stones" has been vigorously debated among researchers, with important implications for the interpretation of the hazard potential of the ongoing eruption. The "restingolites" have been proposed to be either (i juvenile high-silica magma (e.g. rhyolite, (ii remelted magmatic material (trachyte, (iii altered volcanic rock, or (iv reheated hyaloclastites or zeolite from the submarine slopes of El Hierro. Here, we provide evidence that supports yet a different conclusion. We have analysed the textures and compositions of representative "restingolites" and compared the results to previous work on similar rocks found in the Canary Islands. Based on their high-silica content, the lack of igneous trace element signatures, the presence of remnant quartz crystals, jasper fragments and carbonate as well as wollastonite (derived from thermal overprint of carbonate and their relatively high oxygen isotope values, we conclude that "restingolites" are in fact xenoliths from pre-island sedimentary layers that were picked up and heated by the ascending magma, causing them to partially melt and vesiculate. As they are closely resembling pumice in appearance, but are xenolithic in origin, we refer to these rocks as "xeno-pumice". The El Hierro xeno-pumices hence represent messengers from depth that help us to understand the interaction between ascending magma and crustal lithologies

  8. Diversidad de los sistemas de adquisición de hierro mediante sideróforos en Photobacterium damselae subsp. damselae

    OpenAIRE

    Puentes Corral, Beatriz

    2015-01-01

    Photobacterium damselae subsp. damselae es una bacteria Gram-negativa, de la familia Vibrionaceae, que causa un tipo de vibriosis en una amplia variedad de especies marinas, y puede afectar también a animales homeotermos. El hierro desempeña un papel fundamental en el metabolismo y la virulencia de esta bacteria, pero los mecanismos que utiliza para su adquisición, y especialmente los basados en la síntesis de sideróforos, son todavía en gran medida desconocidos. Por tanto, en este trabajo no...

  9. Three-armed rifts or masked radial pattern of eruptive fissures? The intriguing case of El Hierro volcano (Canary Islands)

    Science.gov (United States)

    Becerril, L.; Galindo, I.; Martí, J.; Gudmundsson, A.

    2015-04-01

    Using new surface structural data as well as subsurface structural data obtained from seventeen water galleries, we provide a comprehensive model of the volcano-tectonic evolution of El Hierro (Canary Islands). We have identified, measured and analysed more than 1700 volcano-structural elements including vents, eruptive fissures, dykes and faults. The new data provide important information on the main structural patterns of the island and on its stress and strain fields, all of which are crucial for reliable hazard assessments. We conducted temporal and spatial analyses of the main structural elements, focusing on their relative age and association with the three main cycles in the construction of the island: the Tiñor Edifice, the El Golfo-Las Playas Edifice, and the Rift Volcanism. A radial strike distribution, which can be related to constructive episodes, is observed in the on-land structures. A similar strike distribution is seen in the submarine eruptive fissures, which are radial with respect to the centre of the island. However, the volcano-structural elements identified onshore and reflecting the entire volcano-tectonic evolution of the island also show a predominant NE-SW strike, which coincides with the main regional trend of the Canary archipelago as a whole. Two other dominant directions of structural elements, N-S and WNW-ESE, are evident from the establishment of the El Golfo-Las Playas edifice, during the second constructive cycle. We suggest that the radial-striking structures reflect comparatively uniform stress fields during the constructive episodes, mainly conditioned by the combination of overburden pressure, gravitational spreading, and magma-induced stresses in each of the volcanic edifices. By contrast, in the shallower parts of the edifice the NE-SW, N-S and WNW-ESE-striking structures reflect local stress fields related to the formation of mega-landslides and masking the general and regional radial patterns.

  10. CO2-SO3-rich (carbonate-sulfate) melt/fluids in the lithosphere beneath El Hierro, Canary Islands.

    Science.gov (United States)

    Oglialoro, E.; Ferrando, S.; Malaspina, N.; Villa, I. M.; Frezzotti, M. L.

    2015-12-01

    Mantle xenoliths from the island of El Hierro, the youngest of the Canary Islands, have been studied to characterize fluxes of carbon in the lithosphere of an OIB volcanism region. Fifteen xenoliths (4-10 cm in diameter) were collected in a rift lava flow (15-41 ka) at a new xenolith locality in El Julan cliff (S-SW of the island). Peridotites consist of protogranular to porphyroblastic spinel harzburgites, lherzolites, and subordinate dunites. One spinel clinopyroxenite, and one olivine-websterite were also analyzed. Ultramafic xenoliths were classified as HEXO (harzburgite and dunite with exsolved orthopyroxene), HLCO (harzburgite and lherzolite containing orthopyroxene without visible exsolution lamellae), and HTR (transitional harzburgite with exsolved orthopyroxene porphyroclasts, and poikilitic orthopyroxene) following [1]. While HLCO and HTR peridotites contain mostly CO2 fluid inclusions, HEXO peridotites preserve an early association of melt/fluid inclusions containing dominantly carbonate/sulfate/silicate glass, evolving to carbonate/sulfate/phosphate/spinel aggregates, with exsolved CO2 (± carbonates, anhydrite and H2O). Chemical and Raman analyses identify dolomite, Mg-calcite, anhydrite, sulfohalite [Na6(SO4)2FCl] (± other anhydrous and hydrous alkali-sulfates), apatite, and Cr-spinel in the inclusions. Sulfides are noticeably absent. The microstructure and chemical composition of the metasomatic fluids indicate that the peridotites were infiltrated by a carbonate-sulfate-silicate melt/fluid enriched in CO2, H2O, and P. A mantle origin for this fluid is supported by high densities of CO2inclusions (> 1g/cm3), determined by Raman microspectroscopy and cross-checked by microthermometry. Consequently, El Julan peridotites provide the first evidence for liberating oxidized C and S fluxes from the Earth lithosphere in an OIB source region, and suggest that oxidation of sulfide to sulfate can occur during small-degree partial melting of the upper mantle

  11. Assessing the vulnerability of the evacuation emergency plan: the case of the El Hierro, Canary Island, Spain

    Science.gov (United States)

    Marrero, J. M.; Garcia, A.; Llinares, A.; Lopez, P.; Ortinz, R.

    2012-04-01

    On July 17, 2011 an unrest was detected in the El Hierro island. A serretian submarine eruption started on October 10th in the southern area of the island, two miles away from La Restinga village. The analysis and interpretation of seismic and deformation data show a large volume of intruded magma. These data also show a high probability of a new vent opening. One of the most complex volcanic hazard scenarios is a new open vent in the El Golfo Valley, in the north slope of the island, where more than 5,000 people live. In this area there are only two possible terrestrial evacuation routes: 1) HI-1 road NE direction, the fastest but most vulnerable one, very near a 1,000 meters height cliff and through a 2 km tunnel with a structural deficiency that had to be closed during high energy periods of seismic activity; and 2) HI-1 road SW direction, a mountain road with many curves, frequent small landslides and fog. The Emergency Plan of the island takes into account the entire evacuation of El Golfo Valley in case of eruption. This process will be carried out by means of an assisted evacuation. The evacuees will be transported to a temporally regrouping shelter outside the valley to organize the transport to Tenerife Island. Only those people who have a second residence or relatives outside the affected area will be able to remain in the island. The evacuation time estimated by authorities for the entire evacuation of El Golfo Valley is of about 4 hours. This is extremely low considering: the complexity of the area; the number of evacuees; the lack of preparedness by the population; and adverse weather conditions. To evaluate the Evacuation Plan vulnerability, a series of evacuation scenarios have been simulated: self-evacuation; assisted evacuation; both terrestrial evacuation routes. The warning time, the response time by the population and the evacuation time have been taken into account.

  12. Crustal Deformation During the 2011 Volanic Crisis of El Hierro, Canary Islands, Revealed by Continuous GPS Observation

    Science.gov (United States)

    Sagiya, T.; Barrancos Martinez, J.; Calvo, D.; Padron, E.; Hernandez, G. H.; Hernández, P. A.; Perez Rodriguez, N.; Suárez, J. M. P.

    2012-04-01

    Seismo-volcnic activity of El Hierro started in the middle of July of 2011 and resulted in the active submarine eruption after October 12 south off La Restinga, the southern tip of the island. We have been operating one continuous GPS site on the island since 2004. Responding to the activity, we quickly installed 5 more GPS sites. Including another site operated by the Canary Islands Cartograhical Service (GRAFCAN) for a cartographic purpose, we have been monitoring 7 GPS sites equipped with dual-frequency receivers. We present the result of our crustal deformation monitoring and the magmatic activity inferred from the deformation data. In accordance with the deformation pattern, we divide the volcanic activity in 2011 into 4 stages. The first stage is from the middle of July to middle of September, during which steady magmatic inflation is estimated at the center of the island. The inflated volume of the first stage is estimated to be about 1.3 X 107 m3 at the depth of about 5km. The second stage, which continued until the first submarine eruption on October 12, is characterized by the accelerated deformation due to the upward as well as southward migration of magma. Additional inflation of about 2.1 X 107 m3 occurred in the depth range of 1-2km. The third stage continued for about 3 weeks after the first submarine eruption. During this stage, submarine eruption continues while no significant surface deformation is observed. It is considered magma supply from a deeper magma chamber continued during this 3 weeks period. Therefore, the total inflation volume during the first two stages gives the minimum estimate for the total magma volume. Since the beginning of November 2011, many GPS sites started subsiding. However, this deflation pattern is quite different from those in the shallow inflation stages. Horizontal deformation during this 4th stage is not significant, implying that deflation is occurring below the moho.

  13. Estimulação DDD com eletrodo único usando estimulação atrial bifásica simultânea: primeiros resultados clínicos

    Directory of Open Access Journals (Sweden)

    Fernando A LUCCHESE

    1997-01-01

    Full Text Available A estimulação de dupla câmara (DDD com eletrodo único usando eletrodo atrial flutuante está limitada em função dos altos limiares encontrados para captura atrial. Avaliamos um sistema novo de cabo eletrodo para estimulação atrial que utiliza dois anéis atriais com pulsos de onda quadrada simultâneos unipolares lançados com polaridade oposta. O primeiro pulso é aplicado ao pólo distal do eletrodo e é positivo, o segundo pulso é aplicado ao pólo proximal do eletrodo e é negativo, ambos em relação à carcaça do gerador. O atraso entre os dois pulsos é programável entre 0,0 ms e 1,0 ms. A distância entre os anéis a nível atrial é de 10 mm e a distância entre o pólo distal atrial e o eletrodo ventricular unipolar pode ser selecionado entre 11, 13 e 15 cm. O posicionamento dos anéis a nível atrial é selecionado de acordo com a medida do limiar de estimulação do pulso bifásico simultâneo, incluindo manobras respiratórias para confirmar a captura/sense contínuos. O gerador de pulso tem uma única conexão para o eletrodo e a capacidade de aplicar os pulsos programáveis de onda quadrada com polaridades opostas, com atrasos programáveis de 0,0 a 1,0 ms. O gerador pode ser programado para estimulação VDD com eletrodo único. Este sistema foi implantado em 4 pacientes com bloqueio AV total e função sinusal normal. Os limiares de estimulação atrial e diafragmático foram medidos com várias configurações do pulso, larguras e atrasos, intra e pós-operatórios. A porção média do átrio direito foi selecionada como a melhor posição para os anéis atriais com captura contínua durante inspiração profunda. As medidas intra-operatórias e pós-operatórias (48 horas foram: Limiar Intra-operatório Pós-operatório atrial unipolar 3,2 + 0,47 V não realizada atrial (bifásico simultâneo 1,6 + 0,37 V 3,37 + 0,84 V diafragmático acima de 7 V 5,21 + 0,3 V sense de onda P 2,35 + 1,3 mV 1,27 + 0,8 mV Os pacientes

  14. Short-term volcano-tectonic earthquake forecasts based on a moving mean recurrence time algorithm: the El Hierro seismo-volcanic crisis experience

    Science.gov (United States)

    García, Alicia; De la Cruz-Reyna, Servando; Marrero, José M.; Ortiz, Ramón

    2016-05-01

    Under certain conditions, volcano-tectonic (VT) earthquakes may pose significant hazards to people living in or near active volcanic regions, especially on volcanic islands; however, hazard arising from VT activity caused by localized volcanic sources is rarely addressed in the literature. The evolution of VT earthquakes resulting from a magmatic intrusion shows some orderly behaviour that may allow the occurrence and magnitude of major events to be forecast. Thus governmental decision makers can be supplied with warnings of the increased probability of larger-magnitude earthquakes on the short-term timescale. We present here a methodology for forecasting the occurrence of large-magnitude VT events during volcanic crises; it is based on a mean recurrence time (MRT) algorithm that translates the Gutenberg-Richter distribution parameter fluctuations into time windows of increased probability of a major VT earthquake. The MRT forecasting algorithm was developed after observing a repetitive pattern in the seismic swarm episodes occurring between July and November 2011 at El Hierro (Canary Islands). From then on, this methodology has been applied to the consecutive seismic crises registered at El Hierro, achieving a high success rate in the real-time forecasting, within 10-day time windows, of volcano-tectonic earthquakes.

  15. Spatial and temporal variations of diffuse CO2 degassing at El Hierro volcanic system: Relation to the 2011-2012 submarine eruption

    Science.gov (United States)

    Melián, Gladys; Hernández, Pedro A.; Padrón, Eleazar; Pérez, Nemesio M.; Barrancos, José; Padilla, Germán.; Dionis, Samara; Rodríguez, Fátima; Calvo, David; Nolasco, Dacil

    2014-09-01

    We report herein the results of extensive diffuse CO2 emission surveys performed on El Hierro Island in the period 1998-2012. More than 17,000 measurements of the diffuse CO2 efflux were carried out, most of them during the volcanic unrest period that started in July 2011. Two significant precursory signals based on geochemical and geodetical studies suggest that a magma intrusion processes might have started before 2011 in El Hierro Island. During the preeruptive and eruptive periods, the time series of the diffuse CO2 emission released by the whole island experienced two significant increases. The first started almost 2 weeks before the onset of the submarine eruption, reflecting a clear geochemical anomaly in CO2 emission, most likely due to increasing release of deep-seated magmatic gases to the surface. The second one, between 24 October and 27 November 2011, started before the most energetic seismic events of the volcanic-seismic unrest. The data presented here demonstrate that combined continuous monitoring studies and discrete surveys of diffuse CO2 emission provide important information to optimize the early warning system in volcano monitoring programs and to monitor the evolution of an ongoing volcanic eruption, even though it is a submarine eruption.

  16. Determinación de materia orgánica y hierro en rocas pizarrosas mediante medición de su coloración

    Directory of Open Access Journals (Sweden)

    Encinas, M.

    1990-08-01

    Full Text Available The study of several Palaeozoic shales has allowed to establish a definite correlation between organic matter, or iron content, and colour (as determined with a reflectometer. Hyperbolic curves obtained by plotting the data, show correlation coefficients above 0.9. Colour in rocks is inf!uenced by carbonate content whereas reflectivity is increased by it. Use of a reflectometer, or the Munsell chart of colours, is then proposed as an easy, fast and accurate enough method of estimating organic matter or iron content on this type of pelitic rocks.El análisis de diferentes pizarras paleozoicas ha permitido establecer una correlación positiva entre el contenido en materia orgánica, así como en hierro, y su coloración, medida con un reflectómetro. . Las curvas que mejor se ajustan a los datos obtenidos son las de tipo hiperbólico, con coeficientes de correlación superiores a 0,9. La presencia de carbonatos influye notablemente en el color de las rocas, aumentando los valores de reflectividad. Se propone la utilización de un reflectómetro, o de la carta de colores de Munsell, como un método fácil, rápido y bastante preciso para estimar el porcentaje de materia orgánica y de hierro en este tipo de rocas pelíticas.

  17. Structure and mechanical properties of ductile iron GJS-500-7; Estructura y propiedades mecánicas del hierro dúctil GJS-500-7

    Energy Technology Data Exchange (ETDEWEB)

    Kuryloa, P.; Tertela, E.

    2017-09-01

    The paper presents the results of research on mechanical properties (hardness distribution along the cross section towards the cast’s core) and on the structures of ductile iron GJS-500-7. The study defines the range and form of the surface layer of cast iron. It has been shown that the surface layer of the working surface of the cast may be shaped within its transition zone. [Spanish] El artículo presenta los resultados de la investigación sobre propiedades mecánicas (distribución de la dureza a lo largo de la sección transversal del núcleo de la fundición) y de las estructuras de hierro dúctil GJS-500-7. El estudio define el rango y la forma de la capa superficial de hierro fundido. Se ha mostrado que la capa superficial de la superficie del molde trabajado puede estar conformada dentro de su zona de transición.

  18. Caracterización estructural de vidrios con altos contenidos de óxidos de hierro obtenidos a partir de un residuo de la hidrometalurgia del zinc

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    Romero, M.

    1997-10-01

    Full Text Available It has been carried out the structural characterization of high oxide content glasses obtained by melting of a goethite industrial waste from the zinc hydrometallurgy with other raw materials as dolomite and glass cullet. The structural characterization has been carried out by X-Ray Diffraction (XRD, X-Ray Diffraction by Amorphous Dispersion (RDF and Mossbauer spectroscopy. It has been determined the interatomic distance, the oxidation state and the coordination of iron atoms in these glasses.

    En este trabajo se ha llevado a cabo la caracterización estructural de vidrios con altos contenidos de óxidos de hierro obtenidos por fusión de un residuo industrial de goethita procedente de la hidrometalurgia del zinc con otras materias primas (dolomita y casco de vidrio. El estudio estructural se ha realizado por difracción de rayos-X (DRX, difracción de rayos-X por dispersión amorfa (RDF y espectroscopia Mössbauer, determinándose las distancias interatómicas, el estado de oxidación y la coordinación de los átomos de hierro en este nuevo tipo de vidrios.

  19. Tecnología de desulfuración de fundiciones grises con el fin de obtener hierro con grafito esferoidal // A desulfuration technology for gray iron in order to obtain spheroidal graphite iron

    Directory of Open Access Journals (Sweden)

    A. Batista Cabrera

    1999-01-01

    Full Text Available En el siguiente trabajo se describe una tecnología de desulfuracíon del hierro fundido gris, tomando como base el ya conocidométodo de Volianik (1. En este caso se modificaron algunos parámetros del citado método, adecuándolos a las condicionesexistentes en la Empresa de Fundición de Hierro y Acero de Holguín.( E.F. H. A.Como agente desulfurante se empleó carburo de calcio empleado por Volianik. Como agente activador del desulfurante seutilizó aire comprimido seco. El desulfurante con la granulometría apropiada fue introducido en la cazuela con hierro fundido a1460 oC, por medio de un dispositivo diseñado y construido para este fin.Una gráfica con la dependencia entre el tiempo de soplado y el rendimiento fue obtenida. Como resultado se logró estableceruna tecnología de desulfuración que permite disminuir el contenido de azufre en el hierro fundido desde 0,067 hasta 0,0148%para un rendimiento de 78%.Palabras claves: Hierro gris, desul furación, hierro nodular._____________________________________________________________________AbstractA desulfuration technology for gray cast iron is shown based on the well-known Volianik’s desulfuration method. In this casesome of its parameters were modified, for fitting them to the existent conditions in the Empresa de Hierro Fundido y Acero deHolguín (E.F. H. A..As desulfuration agent calcium carbide was used instead of lime, as it is usually employed by Volianik.Dry compressed air was used as activating agent for the calcium carbide. This one, with the proper grain size it was introducedin a ladle containing 160 RG of melted gray iron at 1460 oC, by means of a mixing device designed and constructed by theauthors.A graphic dependence between air compressed blowing time and desulfuration efficiency was obtained.As a result, a desulfuration technology which permits decrease melted gray iron sulfur contain, from 0,067 till 0,0148 %, wasobtained for a yield of 78 %.Key words: Gray iron, desul

  20. Control del avance del frente de llama en el lecho de sinterización de minerales de hierro

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    Cores, A.

    2010-06-01

    Full Text Available A sintering pan of 40 cm cubed is loaded with a mixture of iron ores, limestone and coke weighing 110 kg in a sintering pilot plant. In this sintering pan, a series of thermocouples have been introduced at different depths. Tests have been carried out to study the width of the combustion zone and the maximum temperature of the flame front across the sintering bed. For the analysis of the results, a data acquisition system was used. This consisted of two modules connected in serie, for performing the analogue-digital conversion. The analogue entry point is the exit point of the thermocouples and the digital exit point was the temperature average. A computer was used for conserving and storing the data and for carrying out interpolations, simulating the state and evolution of the flame front across the bed.

    En una planta piloto de sinterización se cargan, en la paila cúbica de 40 cm de lado, 110 kg de una mezcla de minerales de hierro, caliza y coque, donde se han introducido una serie de termopares a diferentes profundidades. Se realizan ensayos para estudiar la evolución del ancho de la zona de combustión y de la temperatura máxima del frente de llama a través del lecho de sinterización. Para el análisis de los resultados se utiliza un sistema de adquisición de datos formado por dos módulos conectados en serie, encargados de realizar la conversión analógico-digital. La entrada analógica es la salida de los termopares y la salida digital es la medida de la temperatura. Se dispone de un ordenador para la conservación y almacenamiento de los datos y para realizar interpolaciones que simulan el estado y evolución del frente de llama a través del lecho.

  1. La “botiga” del hierro. Fiscalidad y producción industrial en Navarra (1362-1404

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    Mugueta Moreno, Iñigo

    2008-12-01

    Full Text Available The development of the iron industry in the north region of the Kingdom of Navarre was recorded in the fiscal accounts of the royal administration since the second half of the XIII century. However, the Kingdom of Navarre, will not look at this industrial development as a fiscal resource until the second half of the XIV century, with Charles II. The growing needs of his political strategies forced him to increase the fiscal pressure on his citizens, specially since 1362, in the uptake of indirect taxation. The disposed actions of this King will lead him to significantly increase the income earned on the iron industry: first, he seized lordships that were rich in mineral resources and forestry; later he developed a complex tax policy, which even led him to create a monopoly on the iron production in the Kingdom since 1376.

    El origen de la actividad siderúrgica en el norte de Navarra se detecta en los libros de cuentas de la administración real a partir de la segunda mitad del siglo XIII. Sin embargo, no será hasta la segunda mitad del siglo XIV cuando los reyes de Navarra (en concreto Carlos II, vea en este desarrollo industrial una fuente de recursos fiscales. Las crecientes necesidades de sus estrategias políticas le llevaron a un incremento de la presión fiscal sobre sus súbditos, con un especial énfasis desde 1362 en la captación de impuestos indirectos. La acción decidida de este monarca le permitió aumentar notablemente los ingresos percibidos sobre la industria siderúrgica, primero tras la incautación de señoríos nobiliarios ricos en recursos mineros y forestales, y más tarde por medio del desarrollo de un complejo programa fiscal, que incluyó la creación de un monopolio sobre la producción de hierro en el reino desde 1376.

  2. Geología y vulcanología de La Palma y El Hierro, Canarias Occidentales

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    Pérez Torrado, F. J.

    2001-12-01

    important role played by the mobility of the general feeding system of the volcanism in shaping the form and structure of the island. If the volcanism had not continually migrated southward since the final stages of construction of the northern shield, the island of La Palma would probably have taken on a similar configuration to that of the islands of El Hierro or Tenerife, in the shape of a triangular pyramid, with triple-armed rifts and landslide lobes between the rifts. The southward migration of volcanism in La Palma left the northern shield extinct, the rifts incomplete and finally configured an island lengthened in a N-S direction. Another point of interest is that the islands of La Palma and El Hierro are the first of the Canaries to form simultaneously, with possibly alternating eruptive activity, at least in the most recent period. This separation in a «dual line» of islands and the greater depth of its oceanic basement account for the long time they have required to emerge since the formation of the prior island of La Gomera. The island of El Hierro is geologically somewhat younger than La Palma and, because it formed over a stationary source of magma, it presents, in comparison, a perfect, concentric development, with superimposed volcanoes and a regular three-armed rift geometry. The activity of the subaerial volcanism began in El Hierro with the development of Tiñor volcano on the NE flank of the island (approximately from 1.12 to 0.88 ma, with the emission of massive typical basalts. The volcano developed quickly, with different stages of growth, the eruption of Ventejís volcano being the terminal explosive stage, and probably the precursor of the collapse of the NW flank of the edifice some 882 ka ago. The emissions of the new volcano -El Golfo, approximately 545 to 176.000 ka- totally filled the depression of the lateral collapse of Tiñor volcano, the lava flows of which then spilled over the flanks of the earlier volcano. The beginning of the

  3. Efecto del conteo de nódulos en la resistencia al desgaste por abrasión de los hierros dúctiles austemperados

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    C. J. Diez Cicero

    2009-05-01

    Full Text Available Entre los materiales metálicos de mayor demanda, la producción de hierro con grafito nodular, ocupa en la actualidad, uno de los lugares más importantes entre los hierros fundidos de alta resistencia, y con la introducción del tratamiento térmico de austemperado, aplicado a estas fundiciones, se da lugar a una nueva familia de materiales, caracterizados por su alta resistencia mecánica y elevada tenacidad, que mantienen la economía y facilidad de producción de las fundiciones nodulares.Este trabajo, hace una valoración del comportamiento de hierros nodulares, con diferentes conteos de nódulos, a los que les fue aplicado el tratamiento de austemperado, y posteriormente se les sometió a ensayos de desgaste abrasivo. Con los resultados obtenidos, se hace un análisis de la influencia del conteo de nódulos en dichas propiedades, así como también, de la interrelación del conteo de nódulos, con las variables de tratamiento térmico utilizadas en las muestras ensayadas.Between the metallic materials of greater demand, the iron production with nódular graphite occupies at the present time, one of the most important places between fused irons of high resistance, and with the introduction of the austemperado heat treatment of, applied to these smeltings, gives rise to a new family of materials, characterized by its high resistance mechanical and elevated tenacity, that the economy and facility of production of the smeltings maintain nodulares. This work, makes a valuation of the iron behavior nodulares, with different counts from nodules, to which the austemperado was applied treatment to them of, and later it was put under to them tests of abrasive wearing down. Of the obtained results, an analysis takes control of the influence of the count of nodules in these properties, as well as, of the interrelation of the count of nodules, with the used variables of heat treatment in the tried samples.

  4. La anemia por deficiencia de hierro: estrategias de la OPS/OMS para combatirla Iron deficiency anemia: PAHO/WHO strategies to fight anemia

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    WILMA B FREIRE

    1998-03-01

    Full Text Available La anemia por deficiencia de hierro es uno de los problemas nutricionales de mayor magnitud en el mundo. A pesar de conocer su etiología y tener a disposición el conocimiento de cómo enfrentarla y de saber que las intervenciones son de bajo costo, aún no se ha podido superar este problema. Este documento parte de una estimación de la magnitud del problema y plantea los elementos necesarios para el diseño, la ejecución y la medición del impacto de la suplementación con hierro y la fortificación, como las intervenciones más efectivas para disminuir considerablemente la dimensión de la anemia por falta de hierro. Propone una lista de pasos a seguir previos a la elaboración de un proyecto y recomienda una serie de elementos a considerar en ello. Define, asimismo, los aspectos que se deben incluir en una propuesta de fortificación y en otra de suplementación. El documento concluye con un listado de actividades complementarias que la Organización Panamericana de la Salud/Organización Mundial de la Salud ofrece dentro de su paquete de cooperación técnica.Iron deficiency anemia is among the greatest nutritional problems in the world. Although its etiology is understood and intervention at low cost is available, the problem persists. The present review begins with a general estimate of the dimensions of the problem. It suggests the necessary elements for the design, implementation, and measurement of the impact of iron supplementing and fortification as the most effective forms to intervene and diminish iron deficiency anemia. Several preliminary steps are proposed previous to the preparation of a project and several recomendations are made to be included in a project for fortification and iron supplementing. A list of complementary activities offered by PAHO/WHO as part of the package of technical cooperation is included.

  5. Ecotoxicidad de nanopartículas metálicas y superparamagnéticas de óxido de hierro en dos especies

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    Yordanka Domínguez Linares

    2017-10-01

    Full Text Available Introducción: la nanotecnología y el empleo de materiales a nano escala son un área relativamente nueva de la ciencia y la tecnología con un gran crecimiento en el mercado global. Muchos de los productos no cuentan con estudios que garanticen su uso seguro, tanto para el hombre como para los ecosistemas. Los estudios ecotoxicológicos permiten evaluar los efectos de un determinado xenobiótico sobre especies representativas de los diferentes compartimentos ambientales. Objetivo: evaluar los efectos tóxicos de nanopartículas de Ag, Au, Ag/Ag y superparamagnéticas de óxido de hierro, en dos especies bioindicadoras de los ecosistemas terrestre y acuático. Métodos: como parte de los estudios de seguridad se realizaron ensayos de toxicidad aguda por contacto en lombriz de tierra de la especie Eisenia andrei, con una duración de 96 horas y estudios en anfibios de la especie Osteopillus septentrionales en diferentes etapas del desarrollo (embrionario y larval. Se evaluó la ocurrencia de mortalidad y de efectos tóxicos, en el caso del ensayo en lombriz de tierra; se determinó además la viabilidad celular. Resultados: los efectos tóxicos más significativos en el caso de la lombriz de tierra fueron, la ocurrencia de alteraciones fisiológicas y conductuales al ser expuesta a NPs de Ag de 3 nm y superparamagnéticas de óxido de hierro, estas últimas provocaron citotoxicidad a la concentración 1,38 mg/mL. En el caso de los anfibios se evidenció toxicidad en NPs de Ag 3 nm y superparamagnéticas de óxido de hierro. Conclusiones: todas las nanopartículas mostraron efectos tóxicos en las especies bioindicadoras evaluadas.

  6. Evaluación del contenido de hierro total en alimentos de la canasta básica de consumo de los costarricenses

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    Pulina Silva Trejos

    2009-01-01

    Full Text Available Se determinó el contenido de hierro total en 35 alimentos de la canasta básica de consumo de los costarricenses. Los alimentos se escogieron de acuerdo con una encuesta realizada por el comité de usuarios de COSTA RICA FOODS en el 2001. En la muestra se consideraron alimentos de las siguientes categorías: A. Cereales y derivados B. Vegetales y derivados C. Grasas y aceites D. Pescados y productos del mar F. Carnes y derivados E. Leche y derivados J. Huevos y derivados Q. Productos infantiles y R. Productos manufacturados. Las muestras se tomaron trimestralmente durante un año (2005, en los principales supermercados. Los alimentos que requirió cocción, se cocinaron sin aditivos de ninguna clase, tales como aceite y sal; cuando se requirió agua, se utilizó agua desionizada; en todo caso, se utilizaron recipientes de teflón o bien plásticos cuando se cocinaron, en horno de microondas. Una vez cocinados se tomaron muestras por duplicado para la determinación de humedad; el resto se liofilizó y se guardó en recipientes plásticos para la determinación de minerales. La digestión de las muestras se realizó en recipientes cerrados en horno de microondas con ácido nítrico al 65% en masa. El método analítico utilizado para la cuantificación del hierro fue espectroscopia de absorción atómica con llama: como mecanismo de control de calidad, se corrió un SRM de la NIST de matriz similar a la clase de alimento, cada 30 muestras analizadas. Los niveles de hierro total encontrados estuvieron entre 0,3 y 11 mg por 100 g de porción comestible.

  7. The submarine volcano eruption off El Hierro Island: Effects on the scattering migrant biota and the evolution of the pelagic communities

    KAUST Repository

    Ariza, Alejandro

    2014-07-21

    The submarine volcano eruption off El Hierro Island (Canary Islands) on 10 October 2011 promoted dramatic perturbation of the water column leading to changes in the distribution of pelagic fauna. To study the response of the scattering biota, we combined acoustic data with hydrographic profiles and concurrent sea surface turbidity indexes from satellite imagery. We also monitored changes in the plankton and nekton communities through the eruptive and post-eruptive phases. Decrease of oxygen, acidification, rising temperature and deposition of chemicals in shallow waters resulted in a reduction of epipelagic stocks and a disruption of diel vertical migration (nocturnal ascent) of mesopelagic organisms. Furthermore, decreased light levels at depth caused by extinction in the volcanic plume resulted in a significant shallowing of the deep acoustic scattering layer. Once the eruption ceased, the distribution and abundances of the pelagic biota returned to baseline levels. There was no evidence of a volcano-induced bloom in the plankton community. © 2014 Ariza et al.

  8. Petrological and geochemical Highlights in the floating fragments of the October 2011 submarine eruption offshore El Hierro (Canary Islands): Relevance of submarine hydrothermal processes

    Science.gov (United States)

    Rodriguez-Losada, Jose A.; Eff-Darwich, Antonio; Hernandez, Luis E.; Viñas, Ronaldo; Pérez, Nemesio; Hernandez, Pedro; Melián, Gladys; Martinez-Frías, Jesús; Romero-Ruiz, M. Carmen; Coello-Bravo, Juan Jesús

    2015-02-01

    This paper describes the main physical, petrological and geochemical features of the floating fragments that were emitted in the initial stages of the 2011-2012 submarine eruption off the coast of the Canarian island of El Hierro, located 380 km from the Northwest African Coast. It attempts to assess the potential of radiometric analyses to discern the intriguing origin of the floating fragments and the differences between their constituent parts. In this regard, the material that conforms the core of the fragments contains the largest concentration of uranium (U) ever found in volcanic rocks of the Canary Islands. This enrichment in U is not found in the content of thorium (Th), hence the floating fragments have an unusual U/Th ratio, namely equal to or larger than 3. Although the origin of this material is under discussion, it is proposed that the enrichment in U is the result of hydrothermal processes.

  9. Restos de oso pardo en estructuras de la Edad del Hierro del yacimiento de Can Roqueta/Can Revella (Vallés Occidental

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    Albizuri, Silvia

    2008-01-01

    Full Text Available La excepcional recuperación de tres restos de oso pardo en tres estructuras de la primera Edad del Hierro del yacimiento de Can Roqueta, Sector Can Revella, nos llevó a realizar este trabajo de documentación sobre la evidencia de la captura y aprovechamiento del gran carnívoro en un yacimiento del Holoceno catalán. Los restos aparecieron mezclados con desechos de alimentación en el interior de estructuras que han aportado gran cantidad de huesos, y que a priori fueron utilizadas como silos. Una vez inutilizados como contenedores de grano fueron reutilizados como basureros acumulando detritus domésticos entre los que destacan los provocados por la limpieza de hogares (carbones, huesos quemados, piedras, etc....

  10. Obtención de materiales antifricción hierro-arrabio-latón utilizando residuos de virutas de arrabio

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    Nasamov, S. N.

    2003-06-01

    Full Text Available Parts based on iron and steel powders are widely used in the manufacture of automobile and domestic equipment. This work was done to study the anti-friction properties of iron-pig iron-brass compositions of materials which were obtained by pressing and sintering from a mix of iron powders and industrial by products of cast-iron turnings, brass, talc and technical sulphur. Experiments were performed using cold pressure technology in the flowing matrix of the powder composite without solid lubricants. The subsequent sintering was carried out at 1200 ºC under isothermal conditions in a nitrogen atmosphere in the sintering zone during 1 h. The physical-mechanical and anti-friction properties were almost doubled by the active drainage of the gases from the compression mould. The study of the microstructure of the sintered materials showed that free cementite existed between the particle limits and around the pores. Large agglomerations of dark inclusions could be observed, consisting of graphite, zinc and iron oxides, which were points of tension in the material that reduce its durability and, therefore, its wear resistance to dry friction.

    Las piezas base hierro y acero, obtenidas por pulvimetalurgia, tienen gran utilización en la industria del automóvil y de equipos domésticos. El presente trabajo está dedicado al estudio de las propiedades antifricción de materiales de composición hierro-arrabio-latón, aglomerados mediante prensado y sinterización, obtenidos con mezclas de polvos de hierro, residuos industriales de virutas de arrabio, latón, talco y azufre. Los experimentos fueron hechos utilizando la tecnología de prensado en frío, utilizando una matriz fluida, sin empleo de lubricante sólido. Posteriormente, se realizó una sinterización a temperatura de 1.200 °C en condiciones isotérmicas, en atmósfera de nitrógeno, en la zona de sinterización durante una hora. Las propiedades físico-mecánicas y antifricci

  11. Separación selectiva de hierro y cromo de las lejías agotadas del decapado de acero inoxidable

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    Gálvez, J. L.

    2005-12-01

    Full Text Available Stainless steel spent pickling baths are very complex solutions of metals and acids (HNO3 and HF and are a very important environmental concern. Several processes have been developed for acid recovery (free and bounded acid with techniques like acid retardation, solvent extraction, evaporation and dialysis diffusion. In these processes, metallic content is precipitated and treated for its disposal. We have developed a process that permits the separation of metals by means of a selective precipitation, induced by adding free fluoride. Iron (Fe and chromium (Cr precipitate as pentafluorides and nitrogennickel (Ni remains in solution. After this stage, complex fluorides can be hydrolized with alkali to give iron and chromium hydroxides, releasing fluoride in solution

    Los baños ácidos agotados del decapado de acero inoxidable son disoluciones muy complejas debido al alto contenido de metales y ácidos (HNO3 y HF, por lo que constituyen un grave problema medioambiental. Existen tratamientos comerciales para la recuperación del ácido (libre o complejado que se basan en técnicas de retardo ácido, extracción con disolventes, evaporación o membranas. En estos procesos el contenido metálico es precipitado y tratado como un residuo. El grupo de investigación formado por los autores del presente trabajo ha desarrollado un procedimiento que permite el aprovechamiento de dichos metales mediante su recuperación selectiva con una técnica de precipitación modificada inducida por fluoruro libre. Se consigue la precipitación de hierro (Fe y cromo (Cr como pentafluoruros (pH 3-4,5 dejando el níquel en disolución. Posteriormente, los fluoruros complejos son hidrolizados con álcali dando lugar a hidróxidos de hierro y cromo, mientras que el fluoruro es redisuelto.

  12. Processes of Compression-Expansion and Subsidence-Uplift detected by the Spatial Inclinometer (IESHI) in the El Hierro Island eruption (October, 2011)

    Science.gov (United States)

    Prates, G.; Berrocoso, M.; Fernández-Ros, A.; García, A.; Ortiz, R.

    2012-04-01

    El Hierro Island (Canary Islands, Spain) has undergone a submarine eruption a few kilometers to its southeast, detected October 10, on the rift alignment that cuts across the island. However, the seismicity level suddenly increased around July 17 and ground deformation was detected by the only continuously observed GNSS-GPS (Global Navigation Satellite Systems - Global Positioning System) benchmark FRON in the El Golfo area. Based on that information several other GNSS-GPS benchmarks were installed, some of which continuously observed as well. A normal vector analysis was applied to these collected data. The normal vector magnitude variation identified local extension-compression regimes, while the normal vector inclination showed the relative height variation between the three benchmarks that define the plan to which normal vector is analyzed. To accomplish this analysis the data was previously processed to achieve positioning solutions every 30 minutes using the Bernese GPS Software 5.0, further enhanced by a Discrete Kalman Filter, giving an overall millimeter level precision. These solutions were reached using the IGS (International GNSS Service) ultra-rapid orbits and the double-differenced ionosphere-free combination. With this strategy the positioning solutions were attained in near real-time. Later with the IGS rapid orbits the data was reprocessed to provide added confidence to the solutions. Two triangles were then considered, a smaller one located in the El Golfo area within the historically collapsed caldera, and a larger one defined by benchmarks placed in Valverde, El Golfo and La Restinga, the town closest to the eruption's location, covering almost the entire Island's surface above sea level. With these two triangles the pre-eruption and post-eruption deformation suffered by El Hierro's surface will be further analyzed.

  13. Ocre, hematites y óxido de hierro: el problema terminológico = Ochre, Hematite and Iron Oxid: The Terminological Issue

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    Alfredo Cortell Nicolau

    2016-12-01

    Full Text Available Los óxidos de hierro son prácticamente omnipresentes al analizar contextos, no solo referentes al arte rupestre, sino también en relación con toda una serie de actividades que podríamos considerar cotidianas en ambientes prehistóricos. Sin embargo, su estudio sistemático no ha comenzado hasta tiempos muy recientes. Fruto de ello, podría decirse que una parte de la literatura arqueológica no especializada en el campo de la pigmentología muestra, en ocasiones, cierta inexactitud terminológica. Con este documento pretendemos, a través de un análisis tanto de su funcionamiento, como de las propiedades geoquímicas y mineralógicas del ocre, la hematites y los propios óxidos de hierro, exponer la necesidad de propiedad en su nomenclatura, así como los problemas que podrían derivarse de la falta de precisión. Por último, establecemos algunas propuestas que tal vez pudieran ayudar en esta normativización. Iron oxides are virtually omnipresent when analyzing contexts, not only referring to rock art, but also related to a whole series of activities, which we could consider as quotidian for prehistoric environments. Nevertheless, a systematic study of these has not started until recent times. As a result, it could be argued that a part of archaeological literature, not specialized on pigmentology, shows sometimes a certain lack of terminological accurateness. With this document we mean to, through an analysis both of the functioning and the geochemical and mineralogical properties of ochre, hematite and iron oxides themselves, expose the need for an appropriate terminology, as well as to show the problems derived from an inadequate naming. Finally, we bring some proposals, which could maybe help on an appropriate terminological standardization.

  14. Anemia y anemia por déficit de hierro en niños menores de cinco años y su relación con el consumo de hierro en la alimentación. Turbo, Antioquia, Colombia Anemia and iron deficit anemia in children under five years of age and their relation with iron consumption in alimentation, Turbo, Antioquia, Colombia

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    Gloria Margarita Alcaraz López

    2006-09-01

    Full Text Available Objetivo: Determinar la frecuencia de anemia y de anemia por deficiencia de hierro y su relación con el contenido de hierro en la alimentación en niños de 6 meses a 5 años. Materiales y métodos: Estudio descriptivo de corte transversal en el que se estudiaron 113 niños que asistieron a la consulta de crecimiento y desarrollo y al programa de vacunación de la ESE Hospital Francisco Valderrama de Turbo entre el mes de septiembre de 2001 y el mes de junio de 2002. Las pruebas de laboratorio empleadas fueron Hb, ferritina, coprológico directo y sangre oculta en heces. El hierro dietario se estudió con una encuesta semiestructurada. Resultados y discusión: Promedio de Hb 11,3 g/dl (DE 1,4; presentan anemia 48,7%, los más afectados fueron los menores de un año. Promedio de ferritina 47,1 µg/L (DE 58,7, mediana 23,3 µg/L.; 50,4% presentan ferritina baja y de estos, 23,9% presentan agotamiento en los depósitos de hierro. De los 55 niños con anemia 23,6% presentan anemia con deficiencia de hierro. Promedio en el consumo de hierro 7,1 mg/día (DE 3,96; promedio de hierro hemínico de 3,9 mg/día. Promedio de lactancia materna exclusiva: 3 meses. La lactancia se alterna con leche de vaca pasteurizada. De cada 10 menores de un año, 6 tienen anemia con déficit de hierro. Conclusiones: La anemia, la ferritina baja y el bajo consumo de hierro en los niños estudiados perfilan un grave problema de salud pública. Se requiere una política clara y articulada a la cultura de la población para prevenir este problema y sus secuelas en el crecimiento, el desarrollo y en la capacidad cognitiva de los niños.Objective: to determine the frequency of anemia and iron deficit anemia in relation to the iron content in the alimentation of children from 6 months to five years in Turbo. Methodology and materials: transversal descriptive study of 113 children attending the growth, development and vaccination program clinic, from September 2001 to June 2002

  15. The 2011 volcanic crisis at El Hierro (Canary Islands): monitoring ground deformation through tiltmeter and gravimetric observations

    Science.gov (United States)

    Arnoso, J.; Montesinos, F. G.; Benavent, M.; Vélez, E. J.

    2012-04-01

    El Hierro is an ocean island located at the western end of the Canary Islands, and along with Tenerife and La Palma islands have been the most geologically active in the recent past. The island has a triple armed rift and, presently, is at the stage of growth, representing the summit of a volcanic shield elevating from the seafloor at depth of 4000 m up to 1501 m above the sea level (Münn et al., 2006; Carracedo et al., 1999). Since July 19th, 2011 seismic activity has produced more than 11950 events up to date. The seismic crisis resulted in a volcanic eruption that began on October 10th, being still currently active. The new volcano is located 2 km off the coast and about 300 m depth, in the submarine flank of the southern rift of the island, which is extended some 40 km length. Since September 2004 until November 2010 two continuous tilt stations were installed at the north, Balneario site (BA), and at the center of the island, Aula de la Naturaleza (AU) site. Both stations were used to assess the pattern of local ground movements in the island. When seismic swarm started on past July 2011, we have reinstalled both tilt stations (BA and AU) and 2 new ones located at the south of the island, namely Montaña Quemada (MQ) and Restinga (RE) sites. We have used short base platform tiltmeters that measure ground tilts with resolutions varying from 0.1 up to 0.01 microradians (µrad). On October 8th, a 4.4 magnitude earthquake took place and is supposed that fractured the ocean crust at some 8-10 km off the south coast of the island and about 1000 m depth. Typical spike signals were observed at the tilt stations. Two days after, the eruption onset was recorded also at tilt stations through a remarkable increase of the high frequency signal, being of large amplitude the components (radial) orientated towards the new volcano edifice. When compared with previous tiltmeter records in the island, tilt pattern were clearly modified several times at the stations when strong

  16. Síntesis de nanopartículas magnéticas de óxido de hierro para la remoción de arsénico del agua de consumo humano

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    Ricardo Starbird-Pérez

    2015-09-01

    Full Text Available El objetivo de este estudio consiste en proveer un material de alta área de contacto, para ser empleado en el tratamiento de aguas contaminadas con arsénico. Se reporta la síntesis de nanopartículas de hierro con propiedades superparamagnéticas, estabilizadas con ácido esteárico, así como su respectiva caracterización a través de técnicas espectrofotométricas, termogravimétricas y trasmisión electrónica, siendo evidente que la presencia de un emulsificante es determinante para la estabilización de la fase del óxido de hierro (maghemita o magnetita con propiedades magnéticas. El material obtenido muestra adecuadas propiedades para ser utilizado en el tratamiento de agua de consumo humano.

  17. ·En la carne desnuda la escarcha". Modalización lírica y construcción simbólica en la poesía de José Hierro

    OpenAIRE

    Saneleuterio Temporal, Elia

    2011-01-01

    En la Tesis Doctoral “En la carne desnuda la escarcha”. Modalización lírica y construcción simbólica en la poesía de José Hierro se lleva a cabo un recorrido por la obra poética del santanderino de adopción Pepe Hierro (1922-2002) mediante el cual se confirma la hipótesis de que su poesía puede dividirse en dos épocas creativas diferenciadas, correspondientes a dos poéticas también diferentes. Para ello, se analiza la obra del poeta desde dos perspectivas básicas en todo discurso lírico: la m...

  18. Estado de los micronutrientes hierro y vitamina A, factores de riesgo para las deficiencias y valoración antropométrica en niños preescolares del municipio de Funza, Colombia

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    Elpidia Poveda

    2007-03-01

    Conclusión. Existe la necesidad de fortalecer programas fundamentados en las condiciones existentes para mejorar la situación nutricional de los preescolares del municipio de Funza. Es importante indagar si se presenta anemia nutricional relacionada con ácido fólico y vitamina B12, así como sobre otros factores de riesgo asociados con la deficiencia nutricional por hierro y vitamina A.

  19. Relación entre las formas solubles de hierro y manganeso y la presencia de bacterias oxidadoras de ambos elementos en el embalse Riogrande II- Don Matías (Antioquia, Colombia

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    Yamilet Arcos Arango

    2010-01-01

    Full Text Available Entre agosto de 2006 y marzo de 2008 se determinó la presencia de bacterias asociadas a la oxidación de hierro y manganeso en el límite de zona fótica (LZF y en el fondo del hipolimnio (FH en siete estaciones del Embalse Riogrande II en función de la disponibilidad de estos metales. Se realizaron mediciones in situ de temperatura del agua, oxígeno disuelto, pH, potencial redox y conductividad eléctrica. En el fondo del hipolimnio con niveles de oxígeno disuelto ≤ 4mgL-1 solo se encontró presencia de las bacterias oxidantes de hierro compatibles con Gallionella sp, Sphaerotilus sp, Beggiatoa sp y estructuras compatibles con bacterias prostecadas. El mayor número de estas bacterias se observó en el brazo de Río Grande (E4 en donde los niveles de hierro soluble fueron superiores a 1,4 mgL-1 . No se encontró presencia de bacterias dependientes de la oxidación del manganeso.

  20. Comportamiento del hierro sérico y la inmunidad celular en ancianos institucionalizados en el hogar "Santovenia" Behavior of serum iron and the cellular immunity in elderlies institutionalized in "Santovenia" old people home

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    Isabel Martínez Grau

    2009-12-01

    Full Text Available Introducción: relacionado con el estado nutricional, el hierro (Fe es un nutriente esencial para la mayor parte de los tejidos. Objetivo: relacionar la anemia por déficit de hierro con la inmunidad celular en adultos mayores institucionalizados en el hogar de ancianos «Santovenia». Métodos: se realizó un estudio en 41 individuos mayores de 60 años de edad procedentes del hogar de ancianos «Santovenia», 21 portadores de anemia por déficit de hierro y 20 controles normales, a los cuales se les determinó la concentración de hemoglobina (Hb, hematocrito (Hto, hierro sérico (Fe, y se les realizó estudio de la inmunidad celular, roseta activa y roseta espontánea. Resultados: se compararon los resultados del grupo control con los del grupo muestra, para estas variables. Se realizó un estudio estadístico por el test T de Student de comparación de medias, y los resultados fueron una disminución de Hb, Hto, hierro sérico y de la roseta activa y roseta espontánea en el grupo muestra con relación al control, con una diferencia significativa para a = 0,01. Conclusiones: los ancianos que presentaban los valores de Hb más bajos (£ 9, tenían valores de Fe disminuido y la inmunidad celular afectada.Introduction: Related to nutritional status, iron (Fe is an essential nutrient for most of tissues. Objective: To relate the iron-deficiency anemia with the cellular immunity in elderlies institutionalized in "Santovenia" old people home. Methods: Authors conducted a study in 41 subjects aged over 60 from the above mentioned old people home, 21 had iron-deficiency anemia and 20 normal controls, in which we determined the hemoglobin (Hb, hematocrit (Hto, and serum iron (Fe concentrations and also a cellular immunity study, active and spontaneous rosettes. Results: For these variables, results from control and sample group were compared. A statistical study was conducted by Student T test of means comparisons, and results showed a decrease of Hb

  1. Tendencias del uso del suelo en el Valle Amblés (Ávila, España: de la Edad del Hierro al Medievo

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    Antonio BLANCO GONZÁLEZ

    2010-08-01

    Full Text Available : Este trabajo constituye la continuación de otro previo (Blanco González, 2008 con el que comparte objetivos, área de estudio y metodología. Ambos pretenden ofrecer una visión diacrónica de la ocupación humana antigua del Valle Amblés (Ávila, abarcando aquí desde la Segunda Edad del Hierro hasta la plena Edad Media (mediados s. XIII d.C.. En concreto, el análisis territorial se ha enfocado sobre un aspecto económico primordial del poblamiento: el acceso de los productores directos a los recursos agrarios desde los núcleos residenciales. Para ello se ha cuantificado el potencial agrológico de los suelos dentro de los territorios de explotación de una selección de sitios arqueológicos y localidades actuales. La información sobre los yacimientos considerados –de presumible funcionalidad habitacional– procede tanto de prospecciones sistemáticas extensivas e intensivas, como de algunas excavaciones. La calidad agrológica de los suelos de su entorno se ha medido mediante la rutina de un Sistema de Información Geográfica que calcula las superficies de terrenos accesibles en 30 minutos y 1 hora de marcha pedestre desde los sitios. Los resultados, ordenados por épocas, se expresan en hectáreas de las distintas clases agrológicas y se presentan mediante resúmenes gráficos. La mayor discontinuidad se establece en el Hierro II, que actúa como bisagra entre una tendencia prehistórica de fuerte descompensación en los tipos de suelos representados –condicionada por factores de localización de tipo tecnológico o simbólico/políticos– y la tendencia histórica –de clara orientación económica– caracterizada por un estricto equilibrio entre suelos. Se plantea una lectura del proceso histórico que, aunque discontinua –por falta de datos–, informa de los distintos ritmos de intensificación agraria, diversificación productiva e integración sociopolítica en la zona, llegando a su momento álgido al final de la

  2. Evaluación de resinas de intercambio iónico para el control del hierro en soluciones de electro-obtención de cobre

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    Parada, F.

    2010-08-01

    Full Text Available Two commercial resins were evaluated for the extraction of iron from a copper electrowinning solution. Both resins efficiently extract iron. TheMonophosphonic resin has a greater charge capacity than the Diphonix resin and the Diphonix resin shows faster kinetics. Experimental results of the interrupted test and tests with different particle size of resins have demonstrated that extraction kinetics is controlled by diffusion into the particle in both resins. A good agreement with Fick’s model for diffusion inside the particles confirms the proposed mechanism. Finally, temperature favors the process kinetics and its effect on the diffusion coefficient follows Arrhenius law, obtaining a value of 4,89 kcal/mol for theMonophosphonic resin and 4,94 kcal/mol for the Dphonix resin. The aforementioned values are close to typical values for the proposed diffusional control which are 6 to 10 kcal/mol.

    Se evaluaron dos resinas comerciales para la extracción del hierro desde una solución de electro-obtención de cobre. Ambas resinas extraen en forma eficiente el hierro, pero se diferencian en que la resina Monophosphonic tiene una mayor capacidad de carga que la resina Diphonix, mientras que la Diphonix muestra una cinética más rápida. Los resultados de la prueba interrumpida y de las pruebas para determinar el efecto del tamaño de partícula permiten concluir que el control más probable para la cinética de extracción es por la difusión en la partícula en ambas resinas. Un buen ajuste al modelo de Fick para difusión en la partícula confirman el tipo de control propuesto. Finalmente, la temperatura favorece la cinética del proceso de extracción y su efecto en el coeficiente de difusión sigue la ley de Arrhenius obteniendo un valor para la energía de activación de 4,89 kcal/mol para la resina Monophosphonic y 4,94 kcal/mol para la resina Diphonix. Estos valores están cercanos al valor típico para el control propuesto que es de 6 a

  3. Prácticas de manipulación contable de la Compañía de los Caminos de Hierro del Norte de España en el periodo 1900-1923 = Accounting handling practices of la Compañía de los Caminos de Hierro del Norte de España in the period 1900-1923

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    Miguel Ángel Villacorta Hernández

    2014-12-01

    Full Text Available El objetivo del trabajo es analizar si la Compañía de los Caminos de Hierro del Norte de España (NORTE realizó manipulación de la información contable en el periodo 1900-1923. La conclusión fundamental es que para el desarrollo ordinario de su proceso productivo necesitaba los anticipos del personal por parte del Estado, por lo que de forma continuada ofrecía unos resultados económicos inferiores a los que tendría sin manipulación de la información contable. No obstante, puntualmente la empresa necesitó la obtención de recursos del mercado de capitales; para esas situaciones concretas NORTE quería dar una situación de solvencia, por lo que realizó un maquillaje contable para mejorar su apariencia. The objective of this paper is to analyze whether la Compañía de los Caminos de Hierro del Norte de España (NORTE made manipulation of accounting information in the period 1900-1923.The main conclusion is that for the ordinary course of its production process, the company needed personal advances by the government, so continuously offered a lower economic results than it would, without manipulation of accounting information. However, the company promptly needed to obtain resources of capital market; for these situations NORTE wanted to show a solvency position, so it made an accounting make up to enhance their appearance.

  4. Moléculas que participan en el transporte de hierro materno-fetal: importancia del receptor 1 de transferrina y de la ferroportina en la placenta humana = Molecules implicated in maternal-fetal iron transport across the placental barrier: Role of Transferrin Receptor 1 and Ferroportin

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    Corrales Agudelo, Lady Vanessa

    2011-03-01

    Full Text Available La adecuada transferencia placentaria de hierro es crucial para satisfacer los altos requerimientos del feto y promover su adecuado crecimiento y desarrollo intrauterino; de otra parte, contribuye a prevenir la ferropenia y la anemia, entidades altamente prevalentes en los lactantes durante los primeros dos años de edad, que se asocian con mayor morbilidad y mortalidad en la infancia. La placenta es un órgano capaz de realizar diferentes adaptaciones en la producción de moléculas que participan en el transporte de hierro materno-fetal en respuesta al estado de hierro celular, para proveer la mayor disponibilidad de este mineral al feto. Esta revisión, pretende acercar al lector a los mecanismos metabólicos y moleculares relacionados con la captación, el transporte y la salida de hierro por la placenta hacia el feto, así como su regulación, para proporcionar elementos que le permitan comprender en forma integrada, la importancia de un adecuado estado de hierro materno antes y durante la gestación.

  5. Evaluation of the Implementation of an educational intervention nurse in patients treated at the Heart Failure Unit at the University Hospital Puerta de Hierro

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    Aurora Hernández Rivas

    2012-11-01

    Full Text Available Objective: To evaluate the effectiveness of the implementation of a nurse educational intervention in patients with heart failure in relation to the level of knowledge about their disease, level of self-care, treatment adherence, perceived satisfaction, fewer hospital readmissions and improved quality of life. Methods: Quasi-experimental study with two groups: control group (consisting of patients treated according to standard practice and experimental group (consisting of patients who will apply the nursing educational intervention proposal. It included all patients (= 18 years, good cognitive, literacy, sign informed consent with a diagnosis of heart failure (HF of recent (3-6 months or new onset, coming first in the Heart Failure Unit of Hospital Universitario Puerta de Hierro from May 2008. Sample: 68 patients per group. Nurse educational intervention will consist of four teaching sessions of 20 minutes before discharge, will be given a boost educational DVD, complete with brochures and explanatory guide, it will reinforce the information a month by telephone. Monitoring: baseline visit (inclusion and follow-up after 15 days, at 3 and 6 months. Outcomes/Instruments: demographic and clinical/exploration and medical history; quality of life, knowledge, self-care and medication adherence/validated questionnaires. Analysis: measures of central tendency and dispersion. Analysis by treatment assignment.

  6. Probabilistic approach to decision making under uncertainty during volcanic crises. Retrospective analysis of the 2011 eruption of El Hierro, in the Canary Islands

    Science.gov (United States)

    Sobradelo, Rosa; Martí, Joan; Kilburn, Christopher; López, Carmen

    2014-05-01

    Understanding the potential evolution of a volcanic crisis is crucial to improving the design of effective mitigation strategies. This is especially the case for volcanoes close to densely-populated regions, where inappropriate decisions may trigger widespread loss of life, economic disruption and public distress. An outstanding goal for improving the management of volcanic crises, therefore, is to develop objective, real-time methodologies for evaluating how an emergency will develop and how scientists communicate with decision makers. Here we present a new model BADEMO (Bayesian Decision Model) that applies a general and flexible, probabilistic approach to managing volcanic crises. The model combines the hazard and risk factors that decision makers need for a holistic analysis of a volcanic crisis. These factors include eruption scenarios and their probabilities of occurrence, the vulnerability of populations and their activities, and the costs of false alarms and failed forecasts. The model can be implemented before an emergency, to identify actions for reducing the vulnerability of a district; during an emergency, to identify the optimum mitigating actions and how these may change as new information is obtained; and after an emergency, to assess the effectiveness of a mitigating response and, from the results, to improve strategies before another crisis occurs. As illustrated by a retrospective analysis of the 2011 eruption of El Hierro, in the Canary Islands, BADEMO provides the basis for quantifying the uncertainty associated with each recommended action as an emergency evolves, and serves as a mechanism for improving communications between scientists and decision makers.

  7. Fortificación de alimentos con hierro y zinc: pros y contras desde un punto de vista alimenticio y nutricional

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    Boccio José

    2004-01-01

    Full Text Available La deficiencia nutricional de ciertos minerales como el hierro y zinc afectan a la población a escala mundial con graves efectos sobre la salud dependiendo fundamentalmente del grado de incidencia y de la magnitud de la deficiencia. La fortificación de alimentos ha resultado ser la estrategia más efectiva para corregir esta situación con inconvenientes que radican no solamente en la elección del alimento a utilizar como transporte para dichos nutrientes sino también en la correcta elección del compuesto a utilizar como fortificante ya que en general aquellos compuestos que poseen una adecuada biodisponibilidad presentan cambios en las características sensoriales de los alimentos fortificados poco aceptables para su consumo. Los compuestos inertes, que poseen propiedades optimas desde del punto de vista tecnológico poseen una baja absorción que los convierte en compuestos nutricionalmente poco útiles. En este trabajo se discute con mayor detalle estos aspectos con el fin de llegar a un entendimiento más profundo de la problemática antes mencionada.

  8. Applying Fractal Dimensions and Energy-Budget Analysis to Characterize Fracturing Processes During Magma Migration and Eruption: 2011-2012 El Hierro (Canary Islands) Submarine Eruption

    Science.gov (United States)

    López, Carmen; Martí, Joan; Abella, Rafael; Tarraga, Marta

    2014-07-01

    The impossibility of observing magma migration inside the crust obliges us to rely on geophysical data and mathematical modelling to interpret precursors and to forecast volcanic eruptions. Of the geophysical signals that may be recorded before and during an eruption, deformation and seismicity are two of the most relevant as they are directly related to its dynamic. The final phase of the unrest episode that preceded the 2011-2012 eruption on El Hierro (Canary Islands) was characterized by local and accelerated deformation and seismic energy release indicating an increasing fracturing and a migration of the magma. Application of time varying fractal analysis to the seismic data and the characterization of the seismicity pattern and the strain and the stress rates allow us to identify different stages in the source mechanism and to infer the geometry of the path used by the magma and associated fluids to reach the Earth's surface. The results obtained illustrate the relevance of such studies to understanding volcanic unrest and the causes that govern the initiation of volcanic eruptions.

  9. Elementos de diferenciación social en el Bajo Aragón durante el Bronce final-Hierro I

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    Andrés Álvarez García

    2013-11-01

    Full Text Available En el presente trabajo se abordan algunos de los aspectos que más interesan a la denominada Arqueología Social, el relativo a la configuración de las sociedades. Nos proponemos, tomando como base algunos elementos arqueológicos de la zona bajoaragonesa, realizar un intento de aproximación a la realidad de los grupos humanos del Bronce Final y Primer Hierro en esta comarca. No son muchos los elementos de referencia con que contamos por el momento pero algunos de ellos, elementos metálicos, enterramientos, casas, tamaño de los poblados, etc. resultan tremendamente sugestivo como para hacer este intento de acercamiento a los modelos de sociedad de esta zona.This paper analyzes one of the main aspects of the Social Archaeology: the societies configuration. Through some archaeological items found in the Bajo Aragón (Spain we propose an approach to the human societies who lived in this area at the end of Bronze Age and the beginning of Iron Age. Although the number of available items is nowadays very limited, some of them are meaningful enough metallic items, graves, houses, village sizes, . . .- to allow us to deduce how they lived and died.

  10. Multifractal investigation of continuous seismic signal recorded at El Hierro volcano (Canary Islands) during the 2011-2012 pre- and eruptive phases

    Science.gov (United States)

    Telesca, Luciano; Lovallo, Michele; Martì Molist, Joan; López Moreno, Carmen; Abella Meléndez, Rafael

    2015-02-01

    The Multifractal Detrended Fluctuation Analysis (MF-DFA) is an effective method that allows detecting multifractality in non-stationary signals. We applied the MF-DFA to the continuous seismic signal recorded at El Hierro volcano (Canary Islands), which was affected by a submarine monogenetic eruption in October 2011. We investigated the multifractal properties of the continuous seismic signal before the onset of the eruption and after. We analysed three frames of the signal, one measured before the onset of eruption that occurred on October 10, 2011; and two after, but corresponding to two distinct eruptive episodes, the second one started on November 22, 2011 and lasting until late February 2012. The results obtained show a striking difference in the width of the multifractal spectrum, which is generally used to quantify the multifractal degree of a signal: the multifractal spectra of the signal frames recorded during the eruptive episodes are almost identical and much narrower than that of the signal frame measured before the onset of the eruption. Such difference indicates that the seismic signal recorded during the unrest reflects mostly the fracturing of the host rock under the overpressure exerted by the intruding magma, while that corresponding to the eruptive phases was mostly influenced by the flow of magma through the plumbing system, even some fracturing remains, not being possible to distinguish among the two eruptive episodes in terms of rock fracture mechanics.

  11. Estudio arqueometalúrgico de un hacha de hierro encontrada en la villa de "La Olmeda" Palencia, España

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    Gómez de Salazar, José María

    2000-04-01

    Full Text Available The present work shows an iron axe from I to V AD centuries. This piece belongs to an archaeological site from "La Olmeda" (Palencia, Spain where several iron artifacts were found. The metallurgical characterization of ancient iron axe was performed using optical microscopy, SEM-EDX, XRD and hardness test. The data obtained show the fabrication procedure and the technological knowledge of the roman society in "La Olmeda" site.

    En el presente trabajo se estudia un hacha de naturaleza férrea y que forma parte de los numerosos hallazgos encontrados en una villa situada en la provincia de Falencia conocida como "La Olmeda", que ha sido datada entre los siglos I y V dC. Esta pieza ha sido caracterizada microestructuralmente mediante microscopía óptica y electrónica de barrido analítico, así como difracción de rayos X. También ha sido caracterizada mecánicamente mediante análisis de dureza Vickers. Con los resultados obtenidos se ha podido conocer la tecnología metalúrgica utilizada en la fabricación de hachas de hierro de época romana en la provincia de Palencia.

  12. Estudio de la granulación de la mezcla de minerales de hierro en el proceso de sinterización. I parte. Granulación

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    Formoso, Antonio

    2000-08-01

    Full Text Available The granulation process of the ore mixture is described and the fitness for granulation of several iron ores form part of the mixture is studied. With a good granulation and sintering maximum temperature control is possible to achieve the best sintered structure, forming by a hematite nucleous bonded by acicular ferrites. The industrial experience of several types of granulation is described.

    Se describe el proceso de granulación de la mezcla de mineral y se estudia la aptitud a la granulación de una serie de minerales de hierro que forman parte de la mezcla. Con una buena granulación y control de la temperatura máxima de sinterización, se puede conseguir la estructura óptima del sintetizado, formada por un núcleo de hematita rodeado por una red de ferritos aciculares. Se expone la práctica industrial de distintas formas de realizar la granulación.

  13. Tratamiento con trofín en niños intolerantes a las sales de hierro Treatment with trofin in children who do not tolerate iron salts

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    Norma Fernández Delgado

    2000-08-01

    Full Text Available Se realizó tratamiento con Trofín, producto cubano de origen natural con propiedades antianémicas, a 14 niños entre 6 y 36 meses de edad con anemia ferripriva, que no toleraban las sales de hierro oral. Se observó una recuperación de las cifras de hemoglobina en el 86 % de los casos. Se presentaron reacciones adversas ligeras en el 36 % de los pacientes, sin que ello impidiera la continuación del tratamiento. El Trofín constituye una alternativa eficaz en el tratamiento de este déficit nutricional en pacientes intolerantes a las sales ferrosasTreatment with Trofin, a Cuban-made natural product with anti-anemic properties, was given to 14 children aged 6-36 months of age suffering from iron deficiency anemia, who do not assimilate oral iron salts. Adequate levels of hemoglobin figures were observed to be restored in 80% of the cases. 36% of patients showed minor adverse reactions without interrupting the treatment. Trofin is an effective alternative in treating this nutritional disorder in patients who do not tolerate iron salts

  14. Ingesta de hierro y folatos durante el embarazo y su relación con indicadores bioquímicos maternos = Iron and folate intake during pregnancy and its relationship with maternal biochemical indicators

    Directory of Open Access Journals (Sweden)

    Restrepo Mesa, Sandra Lucía

    2012-07-01

    Full Text Available Introducción: la anemia en gestantes es un problema de salud pública en América Latina incluida Colombia.Objetivo: evaluar los indicadores bioquímicos del estado nutricional del hierro y el folato en un grupo de mujeres gestantes pobres vinculadas a un programa nutricional de la Gobernación de Antioquia (Colombia.Materiales y métodos: estudio cuasiexperimental en 26 gestantes, beneficiarias de un programa de educación nutricional, complemento alimentario fortificado con micronutrientes y suplemento de hierro, ácido fólico y vitamina C. Se evaluaron la ingesta dietética por recordatorio de 24 horas, y se midieron la ferritina sérica, la hemoglobina, el volumen corpuscular medio, la proteína C reactiva y el folato sérico; se hizo un coprológico para parásitos intestinales. Se aplicaron la prueba de Pearson para correlacionar la ingesta de folatos con la concentración sérica de los mismos, la prueba de Spearman para correlacionar la ingesta de hierro con la concentración sérica de ferritina, ANOVA de mediciones repetidas para comparación entre los trimestres de gestación y análisis de regresión simple y múltiple para establecer la dependencia de la ferritina, la hemoglobina y el folato sérico con las variables de interés. Se consideró significativo p < 0,05.Resultados: la anemia se previno en 84,6%; la variable más explicativa del cambio en la hemoglobina del tercer trimestre fue su valor en el segundo trimestre. Disminuyó la microcitosis (p = 0,02, pero las gestantes con menor ingesta de hierro tuvieron mayor prevalencia de esta en el tercer trimestre (p = 0,009. La ferropenia aumentó en el transcurso del embarazo (p < 0,001 y se halló correlación positiva entre la ingesta de hierro y la concentración de ferritina en el tercer trimestre (r = 0,64; p < 0,001. La concentración sérica de folato aumentó en el segundo y tercer trimestres (p = 0,018 y se observó una tendencia a la correlación positiva con la ingesta

  15. Factores de riesgo de la anemia por deficiencia de hierro en lactantes de un área de salud Risk factors of iron-deficiency anemia in infants from a health area

    Directory of Open Access Journals (Sweden)

    Hortensia Gautier du Défaix Gómez

    1999-12-01

    Full Text Available Se estudiaron 57 lactantes, supuestamente sanos y tomados al azar, de la población urbana entre 6 y 12 meses de edad de un policlínico de la Ciudad de La Habana, con el objetivo de determinar la frecuencia de anemia por deficiencia de hierro y sus factores de riesgo. Se observó anemia por deficiencia de hierro relacionada con la lactancia materna exclusiva de menos de 4 meses de duración, la introducción temprana e ingestión exagerada de leche de vaca y el antecedente de diarreas e ingresos por esta causa. Se halló además correlación directa y significativa del peso al nacer con la ferritina y de la edad gestacional en el momento del parto con la hemoglobina, así como correlación directa de todos los indicadores de la deficiencia de hierro con la duración de la lactancia materna. El rápido crecimiento corporal, la dieta cuyo componente principal fue la leche de vaca y el aumento de las pérdidas por diarreas, constituyen las causas más frecuentes de deficiencia de hierro en este estudio57 infants who were apparently spund were selected at random from the urban population aged 6-12 months of a polyclinic in Havana City aimed at determining the frequency of iron-deficiency anemia and its risk factors. It was observed that iron-deficiency anemia was connected with exclusive breast feeding of less than 4 months of duration, the early introduction and exagerated ingestion of cow milk and the history of diarrheas and admissions for this cause. A direct and significant correlation was found between birth weight and ferritin and between gestational age at delivery and hemoglobin. A direct correlation of all the indicators of iron-deficiency anemia with the duration of breast feeding was also noted. The rapid body growth, the diet with cow milk as the main component and the increase of losses due to diarrheas were the commonest causes of iron-deficiency anemia according to this study

  16. Anemia and iron, zinc, copper and magnesium deficiency in Mexican adolescents: National Health and Nutrition Survey 2006 Anemia y deficiencia de hierro, zinc, cobre y magnesio en adolescentes mexicanos: resultados de la ENSANUT 2006

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    Vanessa De la Cruz-Góngora

    2012-04-01

    Full Text Available OBJETIVE: To describe the frequency of anemia and iron, zinc, copper and magnesium deficiencies among Mexican adolescents in the probabilistic survey ENSANUT 2006. MATERIALS AND METHODS: The sample included 2447 adolescents aged 12 to 19 y. Capillary hemoglobin and venous blood samples were collected to measure the concentrations of ferritin, sTFR, CRP, zinc, iron, copper and magnesium. Logistic regression models were constructed to assess the risk for mineral deficiencies. RESULTS: The overall prevalence of anemia was 11.8 and 4.6%, body iron deficiency 18.2 and 7.9% for females and males, respectively. Overall prevalence of tissue iron deficiency was 6.9%, low serum copper were14.4 and 12.25%; zinc 28.4 and 24.5%, magnesium 40 and 35.3%; for females and males, respectively. CONCLUSIONS: There is a high prevalence of mineral deficiency in Mexican adolescents; females were more prone to have more mineral deficiencies. Nutritional interventions are necessaries in order to reduce and control them.OBJETIVO: Describir la prevalencia de anemia y deficiencia de hierro, zinc, cobre y magnesio en adolescentes mexicanos en la encuesta probabilística ENSANUT 2006. MATERIAL Y MÉTODOS: La muestra incluyó 2447 adolescentes de 12 a 19 años de edad. Se tomó hemoglobina capilar y muestras de sangre venosa para medir las concentraciones séricas de ferritina, sTFR, CRP, zinc, hierro, cobre y magnesio. Se construyeron modelos de regresión logística para evaluar el riesgo de deficiencia de minerales. RESULTADOS: La prevalencia de anemia fue de 11.8% en mujeres y 4.6% en hombres. Las deficiencias de hierro fueron de 18.2 y 7.9% La deficiencia tisular de hierro fue 6.9%; la baja concentración de cobre fue de 14.4 y 12.25% la de zinc de 28.4 y 24.5%, la de magnesio fue 40 y 35.3% en mujeres y hombres, respectivamente. CONCLUSIONES: Existe una alta prevalencia de deficiencia de minerales en los adolescentes; las mujeres tuvieron mayor riesgo. Son necesarias

  17. Síntesis y caracterización espectroscópica de sulfatos de hierro: implicaciones en astrobiología y la exploración de Marte

    OpenAIRE

    Sansano Caramazana, Antonio

    2015-01-01

    Hay una serie de aspectos que fundamentan la necesidad y el interés de las investigaciones que en este proyecto de tesis se recogen. Por un lado, el interés por los sulfatos de hierro. Estos sulfatos tienen unas características físico químicas y estructurales que suponen un autentico mundo a descubrir y describir, con variadas composiciones, variados comportamientos acido-base y redox, diferentes grados de hidratación y diferentes disposiciones estructurales para mismas composiciones. La ...

  18. Preparación y estudio de fosfato de hierro y litio con diferentes morfologías y su aplicación en baterías de ión-litio

    OpenAIRE

    Trócoli Jiménez, Rafael

    2012-01-01

    La investigación se ha centrado en la mejora de las propiedades electroquímicas del fosfato de hierro y litio, material positivo muy atractivo como electrodo en celdas litio ion. El óptimo comportamiento electroquímico de la estructura fosfolivina está basado en la meseta de potencial originada a 3.5 V. Las principales deficiencias del material, una muy baja conductividad intrínseca y un coeficiente de difusión de litio en la red muy pequeño, son causantes del pobre comportamiento electroquím...

  19. Evolution of submarine eruptive activity during the 2011-2012 El Hierro event as documented by hydroacoustic images and remotely operated vehicle observations

    Science.gov (United States)

    Somoza, L.; González, F. J.; Barker, S. J.; Madureira, P.; Medialdea, T.; de Ignacio, C.; Lourenço, N.; León, R.; Vázquez, J. T.; Palomino, D.

    2017-08-01

    Submarine volcanic eruptions are frequent and important events, yet they are rarely observed. Here we relate bathymetric and hydroacoustic images from the 2011 to 2012 El Hierro eruption with surface observations and deposits imaged and sampled by ROV. As a result of the shallow submarine eruption, a new volcano named Tagoro grew from 375 to 89 m depth. The eruption consisted of two main phases of edifice construction intercalated with collapse events. Hydroacoustic images show that the eruptions ranged from explosive to effusive with variable plume types and resulting deposits, even over short time intervals. At the base of the edifice, ROV observations show large accumulations of lava balloons changing in size and type downslope, coinciding with the area where floating lava balloon fallout was observed. Peaks in eruption intensity during explosive phases generated vigorous bubbling at the surface, extensive ash, vesicular lapilli and formed high-density currents, which together with periods of edifice gravitational collapse, produced extensive deep volcaniclastic aprons. Secondary cones developed in the last stages and show evidence for effusive activity with lava ponds and lava flows that cover deposits of stacked lava balloons. Chaotic masses of heterometric boulders around the summit of the principal cone are related to progressive sealing of the vent with decreasing or variable magma supply. Hornitos represent the final eruptive activity with hydrothermal alteration and bacterial mats at the summit. Our study documents the distinct evolution of a submarine volcano and highlights the range of deposit types that may form and be rapidly destroyed in such eruptions.Plain Language SummaryToday and through most of geological history, the greatest number and volume of volcanic eruptions on Earth have occurred underwater. However, in comparison to subaerial eruption, little is known about submarine eruptive processes as they are dangerous to cruise it over

  20. Estudio experimental sobre el comportamiento del hierro austemperado nitrurado (adi a la fatiga de contacto. // Experimental study to contact fatigue behavior of nitrided-austempered ductile iron.

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    C. Figueroa

    2001-10-01

    Full Text Available En el presente trabajo se muestra un estudio sobre el hierro fundido austemperado nitrurado sometido a pruebas de fatiga decontacto. El mismo se austenitizó y austemperó a las temperaturas de 900 y 3800C respectivamente, seleccionándose enambos casos un tiempo de 2 horas. Después se le aplicó un proceso de nitruración gaseosa a 5700C durante 6 horas.Las experiencias fueron realizadas en una máquina para el ensayo de fatiga de contacto con discos. Las presionesHertzianas utilizadas fueron de 1.73, 1.78, 2.04, 2.41, 2.46 y 2.71 GPa.La composición de fases se determinó utilizando la difracción de rayos X, evidenciándose la presencia de los compuestos e(Fe2-3N y g¢ (Fe4N. Los defectos tales como: pittings spalls y grietas fueron observados por medio de la microscopíaelectrónica de barrido (SEM. Los resultados indicaron que la capa nitrurada entre 5 y 6 micras de espesor desaparece bajola acción de las presiones de contacto. Por otra parte se pudo detectar una disminución de la resistencia a la fatiga en el ADInitrurado cuando fueron utilizadas bajas presiones Hertzianas También se comprobó que los nódulos de grafito actúancomo barreras a la propagación de grietas.Palabras claves: Fatiga de contacto, Capa nitrurada, hierro dúctil austemperado, máquina de fatiga condiscos, rayos X._____________________________________________________________________AbstractThis paper presents a study on the behavior of nitrided austempered ductile iron (ADI under contact fatigue tests. ADI wasaustenitized at 9000C for 2 hours and austempered at 380oC for 2 hours. Later, the ADI was nitrided at 570oC for a periodof 6 hours.The contact fatigue tests were carried out using a disc test machine. Hertzian pressures of 1.73, 1.78, 2.04, 2.41, 2.46 and2.71 were used during the tests.The phase composition of nitride layer was determined using X-ray analysis, which detected the presence of the e and g¢phases. The pitting, spalls and cracks that appeared

  1. Racionalización de mezclas de minerales de hierro para la obtención de sinterizados de calidad optima

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    Cores, A.

    2009-06-01

    Full Text Available Various iron ores, fluxes and coke, were used to prepare four ore mixtures with different proportions of these minerals. With each mixtures a series of sinters were produced in the pilot plant. Each one of the sinters was characterised by: chemical and granulometric analysis; degradation test on the sinter during reduction in the blast furnace, (RDI test; cold resistance test, (Tumbler Test; reducibility test; determining of softening and melting temperatures; and the determination of the structure of the sinter by electron microscopy. T he conditions of the mixtures and the operational parameters for obtaining the optimum quality of the sinters were established.

    Se utilizaron diversos minerales de hierro, fundentes y coque para preparar cuatro mezclas minerales con distintas proporciones de estos minerales. Con cada mezcla se fabricó una serie de sinterizados en planta piloto. Se caracteriza cada uno de los sinterizados mediante análisis químico y granulométrico, ensayo de la degradación del sinterizado durante la reducción en el horno alto (ensayo RDI, ensayo de la resistencia en frío (ensayo Tumbler, ensayo de reductibilidad; determinación de las temperaturas de reblandecimiento y fusión y determinación de la estructura del sinterizado por microscopia electrónica. Se establecen las condiciones de las mezclas y los parámetros de operación para la obtención de sinterizados de calidad óptima.

  2. Tendencias del uso del suelo en el Valle Amblés (Ávila, España. Del Neolítico al Hierro Inicial

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    Antonio BLANCO GONZÁLEZ

    2009-08-01

    Full Text Available RESUMEN: Este trabajo avanza una exploración preliminar, en clave diacrónica, de la explotación agropastoril del Valle Amblés (Ávila desde los primeros grupos agrarios hasta la Edad del Hierro. Se ha elegido una unidad geográfica con un nivel aceptable de información arqueológica y complementariedad paisajística entre las ocupaciones del fondo de valle, de tradicional explotación agropastoril y las zonas serranas, de vocación pastoril y forestal. En ese marco de estudio se han estudiado los territorios de explotación de un centenar de sitios de carácter habitacional, clasificados según criterios estilísticos de cultura material, tratando de evaluar de forma cuantitativa la potencialidad agraria de los terrenos en su entorno. Usando modelos de coste-distancia en un Sistema de Información Geográfica (SIG se han generado los polígonos correspondientes a media hora y una hora de marcha a pie desde cada yacimiento. Con ellos se han medido las superficies de los suelos clasificados según el sistema de evaluación del Mapa de Clases Agrológicas. Los resultados se describen mediante simples resúmenes numéricos y gráficos para ofrecer una lectura preliminar de los contrastes en el tiempo, advirtiéndose la parcialidad de una interpretación directa de los mismos, sin considerar otros factores locativos. En todas las etapas queda clara la tendencia a explotar diferentes tipos de suelos, relacionada con el acceso a un amplio rango de recursos complementarios entre estas comunidades campesinas. Los principales cambios se acusan a comienzos de las Edades del Bronce y del Hierro, conforme con las discontinuidades manifiestas en otros aspectos del registro arqueológico. Se aprecia una relación significativa entre la importancia del acceso a las tierras óptimas para una agricultura primitiva y los momentos de mayor sequía. Los suelos que requieren mayores inversiones de trabajo en infraestructuras agrarias y tecnologías de laboreo m

  3. Influencia del ejercicio físico aeróbico durante el embarazo en los niveles de hemoglobina y de hierro maternos. (Influence of the physical aerobic exercise during pregnancy in the maternal haemoglobin and iron levels.

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    James Stirling

    2008-04-01

    Full Text Available Resumen Son bien conocidos los efectos beneficiosos que el ejercicio físico tiene sobre la salud en general, aunque no se cuenta con la misma información cuando se desarrolla durante el embarazo. La mayor incertidumbre es saber si pueden coexistir ambos procesos, ejercicio y embarazo, sin conflictos materno-fetales y sin resultados del embarazo alterados. Especialmente cuando día a día, son más las mujeres que desean continuar ejercitándose de alguna forma, durante su embarazo. El objetivo de este trabajo es conocer la influencia del ejercicio físico aeróbico moderado desarrollado durante el segundo y tercer trimestres en los niveles de hemoglobina y de hierro maternos. Material y métodos: Se llevó acabo un estudio experimental que incluyó un total de 142 gestantes. Grupo casos: integrado por 72 mujeres. Grupo control: integrado por 70 mujeres. Los parámetros maternos estudiados fueron: niveles de hierro, nivel de hemoglobina previo al parto, edad gestacional, tipo de parto. Fetales: Peso de nacimiento, talla, perímetro craneal, test de Apgar (1´y 5´. Resultados: No se encontraron diferencias significativas a nivel estadístico entre ambos grupos (p menor que 0,05, el grupo de casos (ejercicio presento medias similares en los niveles de hemoglobina: 12.1 ± 0.8 y de hierro: 65.90 ± 7.1; que el grupo de control: hemoglobina: 12.3 ± 0.8 y hierro: 66.42 ± 8.4. El peso de nacimiento fue inferior en el grupo de casos dentro de valores normales (-142.1 grs.. Conclusión: El ejercicio aeróbico moderado desarrollado durante el segundo y tercer trimestre de embarazo parece no alterar los niveles de hierro y hemoglobina maternos. Abstract They are very well-known the beneficial effects that the physical exercise has about the health in general, although it is not had the same information when it refers to a pro- cess of remarkable importance: the pregnancy. The biggest uncertainty is to know if both processes, exercise and pregnancy can

  4. Óxidos de hierro libres asociados a carbono orgánico en agregados de suelos del partido de Balcarce Free iron oxides associated to organic carbon in soils aggregates in Balcarce county

    Directory of Open Access Journals (Sweden)

    Fabián Néstor Cabria

    2005-07-01

    Full Text Available Cuando la materia orgánica es el agente estabilizador principal y la estructura de los agregados es jerárquica, el mecanismo de formación de los agregados conduce a recluir el carbono orgánico en macroagregados estables. Este concepto surge de investigaciones que estudiaron el modo en que la labranza altera la formación y degradación de agregados y, consecuentemente, la dinámica natural de la materia orgánica particulada y asociaciones órgano-minerales. No contando con información local que corrobore cual es el contenido de carbono orgánico asociado a minerales dentro de los agregados y, además, entendiendo que una mejor información sobre la naturaleza y dinámica de las asociaciones órgano-minerales redundará en el entendimiento de la dinámica de la estructura y del secuestro y ciclo del carbono en los suelos, en este trabajo se extrajeron químicamente óxidos de hierro asociados al carbono orgánico en distintos tamaños de agregados en tres series de suelos bajo agricultura continua con labranza convencional (ACLC y paturras cultivadas (PC. Los resultados conducen a entender que la ferrihidrita, óxido de hierro paracristalino, sería un constituyente de las asociaciones órgano-minerales. La cantidad de este mineral disminuiría bajo ACLC, pero la magnitud de este resultado no fue similar en las tres series de suelo. En los dos sistemas de manejo el hierro removido desde los óxidos de hierro asociados al carbono orgánico fue más abundante en los macroagregados que en los microagregados. Bajo ACLC el hierro disminuyó en los macroagregados y aumento en los microagregados. Nosotros sugerimos que en los suelos disturbados el secuestro de carbono orgánico asociado a minerales, ferrihidrita, entre otros, ocurriría dentro de los microagregados que finalmente son recluidos en macroagregados estables.When organic matter is the principal stabilizing agent and soil aggregates structure is hierarchical, the mechanism of formation

  5. Energy saving using solar filters with iron base in windows; Ahorro de energia usando filtros solares con base en hierro en ventanas

    Energy Technology Data Exchange (ETDEWEB)

    Chavez Galan, Jesus

    2003-07-01

    termico generado al interior de las edificaciones por las inadecuadas propiedades de los materiales de construccion, se desarrollaron en este trabajo filtros solares con base en hierro por medio de los cuales se logra un control selectivo de la radiacion solar que se transmite a traves de las ventanas. Estos filtros solares consisten en peliculas delgadas de FeO depositadas sobre sustratos de vidrio cal-sosa (el mas usado en nuestro pais para las edificaciones) de 600x300x3 mm, por medio de la tecnica de sputtering asistida con radiofrecuencia y magnetrones planos, partiendo de un blanco de hierro puro de 127x254 mm y usando un plasma de argon. Para obtener el grado de oxidacion deseado en el hierro, pequenas muestras (45 x 22 mm) fueron sometidas a un proceso de calentamiento en una atmosfera reductora constituida de 50% H{sub 2} + 50% N{sub 2}, durante un periodo de tiempo de 10 minutos a una temperatura de 400 C. Los filtros solares con base en FeO presentan una transmisividad de 30.2% para el intervalo visible del espectro electromagnetico (radiacion con longitud de onda de 380-780 nm), y de 39.9% para el infrarrojo cercano (radiacion con longitud de onda de 780-2500 nm); mientras que su reflectividad es de 17.5 y 19%, para los intervalos visibles e infrarrojo cercano del espectro electromagnetico respectivamente. Se realizo una simulacion, a traves del software Energy 10, del comportamiento energetico de una casa-habitacion cuando utilizan en las ventanas vidrios simples (una lamina) tipo cal-sosa, asi como tambien cuando esta misma edificacion usa en las ventanas los filtros solares con base en FeO desarrollados. Ambos casos se comparan obteniendose asi los posibles ahorros de energia por el uso de dichos filtros solares en las ventanas. Las simulaciones fueron llevadas a cabo para diferentes localidades del pais, obteniendose que los filtros solares con base en FeO desarrollados, permiten ahorros de energia principalmente por concepto de acondicionamiento de aire

  6. A new approach to the unrest and subsequent eruption at El Hierro Island (2011) based on petrological, seismological, geodetical and gravimetric data

    Science.gov (United States)

    Meletlidis, Stavros; Di Roberto, Alessio; Domínguez Cerdeña, Itahiza; Pompilio, Massimo; García-Cañada, Laura; Bertagnini, Antonella; Benito Saz, Maria Angeles; Del Carlo, Paola; Sainz-Maza Aparicio, Sergio; Lopez Moreno, Carmen; Moure García, David

    2014-05-01

    A shallow submarine eruption took place on 10th October 2011, about 1.8 km off the coast of La Restinga, a small village located in El Hierro (Canary Islands, Spain). The eruption lasted for about four months and ended by early March 2012. The eruption was preceded by an unrest episode that initiated about three months before, in July 2011, and characterized by more than 10,000 localized earthquakes accompanied by up to 5 cm of vertical ground deformation. In the Canary Islands, this event represents the first case of an eruption that was monitored since the unrest to the end by the monitoring network of IGN (Instituto Geográfico National), providing a huge dataset that includes geophysical (seismic, magnetic and gravimetric), geodetic, geochemistry and petrological data. In this work we use the seismic, GPS and gravity records collected by IGN along with the petrological data derived from the study of various lava balloons, scoriaceous fragments and ash.Geophysical and geochemical monitoring tools provide a variety of information that need to be interpreted in terms of magma movement and/or interaction of magma with host rocks. We present a model, based on this data, which describes the intrusion and ascent of the magma. According to this model, a major intrusion beneath and around preexisting high-density magmatic bodies, localized in the central sector of the island, led to an eruption in the Southern sector of the island. After a failed attempt to reach the surface, while various dykes were emplaced, through a low fractured area in the Central and Northern parts of the island, the ascending magma finally found its way in the submarine area of La Restinga, in the South rift zone, at a depth of 350 m below sea level. Feeding of the eruption was achieved by the ascension of an important volume of material from the upper mantle which was emplaced near the crust-mantle boundary. However, the very energetic post-eruptive unrests - we had five episodes up today with

  7. Estudio comparativo del comportamiento electroquímico del hierro en medio alcalino en presencia de lodos rojos y lodos grises. Efecto del Al3+

    Directory of Open Access Journals (Sweden)

    Abreu, C. M.

    2009-02-01

    Full Text Available Red mud (RM is the main by-product of the Bayer process for alumina extraction from bauxite, and grey slurries (GS are generated during the granite rocks transformation processes. The huge volume of those wastes generated every year suppose a serious environmental problem. Recent works by our group demonstrate the efficiency of both types of muds as corrosion inhibitors for iron and steel in alkaline media containing chlorides. The elemental analysis of these slurries shows that Al3+ is the main common element. Therefore, the aim of this paper is to study the effect of the soluble Al3+ in the electrochemical behaviour of iron in alkaline media, in presence and absence of chlorides. The electrochemical study using Cyclic Voltammetry (CV and Electrochemical Impedance Spectroscopy (EIS together with surface analysis techniques allowed to conclude that Al3+ blocks the surface of steel in alkaline media chloride increasing the steel resistance to chloride attack.

    Los elevados volúmenes de residuos generados por los lodos rojos (LR, procedentes del proceso de obtención de la alúmina a partir de la bauxita y los lodos grises (LG, originados durante el proceso de la transformación del granito, suponen un grave problema medioambiental. Trabajos recientes de este grupo demuestran la eficacia de ambos tipos de lodos como inhibidores de la corrosión del hierro y acero en medio alcalino clorurado. Esta característica ha llevado al estudio individualizado de sus componentes mayoritarios y, dentro de éstos, el Al3+, elemento común presente en mayor proporción. El estudio mediante técnicas electroquímicas como la Voltametría Cíclica (VC y la Espectroscopía de Impedancia Electroquímica (EIE, apoyadas en técnicas de análisis químico y superficial, ha permitido visualizar cómo el Al3+ es capaz de bloquear la superficie del acero en medio alcalino aumentando su resistencia al ataque

  8. Estudio de corrosión galvánica en pares latón/acero inoxidable y latón/fundición de hierro

    Directory of Open Access Journals (Sweden)

    Ohanian, M.

    2011-08-01

    Full Text Available Corrosion attack in heat exchanger systems is a topic of main interest for the maintenance in each industrial plant. These are multigalvanic systems with particular geometric and fluidodynamic complexity. Corrosive damages include zinc selective dealeation in copper alloys. In order to explain zinc dealeation attack, this paper deals with laboratory scale testing, characterization and interactions between two copper and zinc alloys (Yellow brass –UNS C268– and Admiralty brass –UNS C443– compared to AISI 316 stainless steel and cast iron. The tests were performed at 20 °C in 1.5 % NaCl and 1.5 % Na2SO4 solutions, pH 8 and each material was characterized by potentiodynamic sweeps. The couples are analyzed by studying transient galvanic currents. We conclude about the cause of the analyzed pathology, brass protection potential ranges and its coupling compatibility with other metals.

    El ataque por corrosión en los sistemas intercambiadores de calor constituye un problema para el mantenimiento de cualquier planta industrial. Se trata de sistemas multigalvánicos con particular complejidad geométrica y fluidodinámica. Las patologías corrosivas incluyen el fenómeno de dealeación selectiva de cinc en las aleaciones de cobre. A fin de explicar un caso particular de ataque por decinficación (deterioro en placa de intercambiador de calor de tubos de inoxidable, el presente trabajo aborda en ensayos a escala de laboratorio, la caracterización e interacciones entre dos aleaciones de cobre y cinc, (Yellow brass –UNS C268– y Admiralty brass –UNS C443–, respecto a acero inoxidable AISI 316 y fundición gris de hierro. Los ensayos se realizan a 20 °C en disoluciones de NaCl 1,5 % y Na2SO4 1,5 % y pH 8. Se caracterizan electroquímicamente las aleaciones y materiales involucrados mediante barridos potenciodinámicos. Los pares galvánicos formados se analizan mediante el

  9. Iron, zinc and iodide status in Mexican children under 12 years and women 12-49 years of age: a probabilistic national survey Estado de hierro, zinc y yodo en niños menores de 12 años y en mujeres de 12-49 años de edad en México: una encuesta probabilística nacional

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    Salvador Villalpando

    2003-01-01

    Full Text Available OBJECTIVE: To describe the epidemiology of iron, zinc and iodide deficiencies in a probabilistic sample of Mexican women and children and explore its association with some dietary and socio-demographic variables. MATERIAL AND METHODS: We carried out in 1999 an epidemiological description of iron (percent transferrin saturation, PTS, OBJETIVO: Describir la epidemiología de las deficiencias de hierro, zinc y yodo en una muestra probabilística de mujeres y niños mexicanos y analizar algunas asociaciones con factores dietéticos y sociodemográficos. MATERIAL Y MÉTODOS: Descripción epidemiológica de las deficiencias de hierro (Porcentaje de saturación de transferrina <16%, zinc (<65ug/dl y yodo (<50ug/l orina en una muestra probabilística de 1363 niños y 731 mujeres. Las concentraciones séricas de hierro, y la capacidad total de saturación de hierro y zinc se midieron por espectrometría de absorción atómica, y el yodo por un método colorimétrico. Los determinantes de tales deficiencias se estudiaron mediante modelos de regresión logística. RESULTADOS: La deficiencia de hierro fue mayor (67% en niños <2 años de edad. La prevalencia disminuyó en los escolares (34-39%. La prevalencia de deficiencia de hierro en mujeres fue de 40%. La deficiencia de zinc fue mayor en niños <2 años de edad (34% que en escolares (19-24%. La prevalencia en mujeres fue de 30%, sin diferencia rural/urbana. La probabilidad de tener deficiencia de hierro en mujeres disminuyó con el nivel socio-económico (p=0.04 y aumentó con la ingestión de cereales (p=0.01. La probabilidad de tener concentraciones bajas de zinc sérico fueron mayores en mujeres de nivel socioeconómico (SES bajo (p=0.02 y p=0.001. La prevalencia de deficiencia de yodo fue casi inexistente tanto en niños como en mujeres. CONCLUSIONES: Los datos demuestran una alta prevalencia de deficiencia de hierro, especialmente en niños de 12 a 24 meses de edad. Se sugiere que en niños mayores

  10. Prevalencia de deficiencia de hierro y yodo, y parasitosis en niños de Arandas, Jalisco, México Prevalence of iron and iodine deficiency and parasitosis in children from Arandas, Jalisco, Mexico

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    Edgar Manuel Vásquez-Garibay

    2002-06-01

    Full Text Available Objetivo. Estimar la prevalencia de deficiencia de hierro, yodo y parasitosis en niños que asisten al Instituto Alteño para el Desarrollo de Jalisco (Inadej, Arandas, Jalisco, México. Material y métodos. Estudio transversal efectuado entre 1997 y 1999 con 432 niños de 12 a 120 meses de edad, de nuevo ingreso al Inadej. Se determinaron variables hematológicas, yodo en orina y presencia de parásitos. Se utilizaron las pruebas Ji cuadrada y t de Student en variables no paramétricas y paramétricas. Resultados. Hubo más anemia (20 vs 7.4% p=0.007 y deficiencia de hierro (60.9 vs 44.4% p=0.02 en prescolares que en escolares. El 29% presentaron deficiencia de yodo (10.5% moderada o grave y 47.2% parasitosis. Predominaron G. lamblia y E. histolytica. Bajo salario, sexo masculino y no tener seguridad social se asociaron con parasitosis. Conclusiones. La elevada prevalencia de deficiencia de hierro, yodo y parasitosis obliga al sector salud estatal a ejecutar medidas eficaces para abatir estas enfermedades prevenibles.Objective. To estimate the prevalence of iron deficiency, iodine deficiency and parasitosis in children attending the Instituto Alteño para el Desarrollo de Jalisco ((Highlands Institute for Development of Jalisco State, INADEJ, Arandas, Jalisco, Mexico. Material and Methods. A cross-sectional study was conducted between 1997 and 1999, among 432 children aged 12 to 120 months attending the INADEJ. Measurements included hematological values, urine iodine concentration, and presence of parasites. Student's t test chi square tests were used for parametric and non-parametric analysis. Results. The prevalence figures of anemia (20 vs 7.4%, p=0.007 and iron deficiency (60.9 vs 44.4%, p=0.02 were higher in preschool than in school children. Iodine deficiency was found in 29% (10.5% moderate or severe and parasitosis in 47.2% of children, mainly E. histolytica (30.2% and G. lamblia (28.9%. Low income, male gender and lack of social

  11. Efecto del tipo de lactancia durante el primer año de vida sobre el estado de hierro y el desarrollo físico y psicológico del niño

    OpenAIRE

    Bedmar Carretero, Cristina

    2012-01-01

    El objetivo de este estudio fue valorar el desarrollo del niño durante el primer año de vida en función del tipo de lactancia realizada durante el primer semestre y de la dosis de hierro administrada durante el segundo semestre. El 75,5% realizan lactancia materna exclusiva al nacer y el 16,5% la mantienen hasta los 6 meses. El 39,5%tienen alguna mutación en el gen HFE. La prevalencia de déficit de hierroy anemia ferropénicaes del 4,5% y 2,5% a los 6 meses y del 9,2% y 1,2% a los 12 meses.La ...

  12. Influencia de la concentración de hierro y pH iniciales en un proceso de biodesulfurización de carbón – ensayos a nivel de laboratorio

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    Gerardo Andrés Caicedo Pineda

    2011-07-01

    Full Text Available Título en ingles: Particle size, iron concentration and pH influence in biodesulfurization process of coal – laboratory tests   Resumen   A un carbón proveniente del municipio de Puerto Libertador, Córdoba-Colombia (2.34% de azufre total, con 1.34% pirítico, 0.90% orgánico y 0.10% de sulfatos, se le aplicó un cultivo mixto de Acidithiobacillus ferrooxidans y Acidithiobacillus thiooxidans, con el fin de evaluar procesos de biodesulfurización en suspensión, a partir de variables que influyen en el proceso: concentración inicial de hierro y pH de la solución lixiviante, bajo dos configuraciones de tamaño de partícula: pasante malla 8 (-malla 8 y pasante malla 60 (-malla 60, acorde con la serie Tyler de tamices. Los procesos de biodesulfurización se evaluaron cada dos días, mediante mediciones de la concentración de hierro, pH, potencial de óxido-reducción y crecimiento celular, en la solución. A partir de los ensayos realizados, se alcanzaron oxidaciones de azufre pirítico por encima del 50%, después de 12 días de proceso. Se pudo constatar que tanto el tipo de carbón tratado, como de las condiciones evaluadas, inciden en el grado de lixiviación alcanzado. La mejor eficiencia del proceso se observó al utilizar concentraciones de hierro iniciales menores a 1200 ppm y un pH inicial entre 1.5 y 1.3.   Palabras clave: Acidithiobacillus, biodesulfurización, carbón, hierro removido, pirita.   Abstract   Biodesulfurization process for Colombian coal (2.34% total sulfur: 1.34% as pyritic, 0.90% as organic and 0.10% from sulfates from municipality of Puerto Libertador (Córdoba, Colombia was carried out. A mixed culture of A. ferrooxidans and A. thiooxidans was used. The study was mainly focused on the influence of pH, and iron concentration in coal leaching process. Two mineral particle sizes were evaluated: less 8 mesh (-malla 8 and less 60 mesh (-malla 60, Tyler series. Biodesulfurization processes were determined by

  13. Prevalencia de anemia y deficiencia de hierro en escolares jujeños de 12 años Prevalence of anemia and iron deficiency in 12 year old school children from Jujuy

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    María C. Buys

    2005-04-01

    Full Text Available La deficiencia de hierro es una de las deficiencias de micronutrientes más comunes. Los adolescentes son un grupo vulnerable. Un reconocimiento oportuno puede prevenir una anemia ferropénica, etapa final y grave de dicha deficiencia, insuficientemente conocida en nuestro país. El objetivo de este estudio fue determinar los valores hematológicos en adolescentes y conocer las prevalencias de anemia y deficiencia de hierro. Definidas como a anemia: hematocrito (Hto Iron deficiency is highly frequent among adolescents. Its early detection can prevent the development of a ferropenic anemia, a serious condition. The problem has not been well studied in our country. The purpose of this work was to determine the frequency of iron deficiency and anemia in adolescents. The criteria considered were: hematocrit below 38%, b saturation transferrin below 16%, c ferritin below 15 ng/ml. The study was carried out in 2.265 schoolchildren, 12 years old, of both sexes, in urban and periurban areas in the city of San Salvador de Jujuy (1.250 a.s.l.. The following parameters were measured: hematocrit as well as serum iron and total iron binding capacity, both by colorimetric method. Ferritin was measured by ELISA. Anemia was not found. Iron deficiency as estimated by the iron functional component, was found in 25% of girls and 21% of boys and, through iron stores, in 28% of girls and 18% of boys. Iron deficiency stores in both sexes is the more relevant alteration, indicating that the population sample here studied constitutes a highly vulnerable group. The early detection of iron deficiency will help physical and intellectual development so that adequate sanitary policies are necessary for its prevention.

  14. Disponibilidad de cobre, hierro, manganeso, zinc en suelos del NO argentino Pant availability of copper, iron, manganesum and zinc in the north west of Agentina

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    Núria Roca

    2007-07-01

    Full Text Available Cobre, hierro, manganeso y zinc son cuatro metales esenciales para el crecimiento vegetal. A pesar de las pequeñas cantidades requeridas por las plantas, los suelos agrícolas suelen ser deficitarios en uno o más micronutrientes de forma que su concentración en los tejidos de los vegetales cae por debajo de los niveles que permiten un crecimiento óptimo. La naturaleza del suelo juega un papel fundamental en la disponibilidad de micronutrientes y en su comportamiento a nivel suelo-planta. Los objetivos planteados en el presente estudio son: a establecer la relación entre los parámetros edáficos y la dinámica de los metales dentro del perfil del suelo, y b determinar la biodisponibilidad y zonas de deficiencia de micronutrientes en suelos agrícolas y suelos con riesgo de salinización. El porcentaje de materia orgánica es el factor determinante en el contenido y distribución de los micronutrientes en el suelo objeto de estudio, siendo el horizonte superficial el de mayor acumulación. Tanto CuDTPA, FeDTPA como MnDTPA tienen cierta movilidad en el perfil, mientras que ZnDTPA permanece adsorbido sin un desplazamiento vertical. El ZnDTPA es el único metal que además, muestra diferencias como consecuencia de la salinidad y granulometría de los suelos. No obstante, las condiciones geoquímicas del suelo implican una baja extractabilidad y una cierta dificultad de absorción de los micronutrientes por parte de las plantas.Copper, iron, manganese and zinc are among the essential elements for plant growth. Despite the small amounts required by plants, agricultural soils are usually deficient in one or more of these micronutrients. Therefore, their concentration in plant tissues falls below the optimum levels. Soil nature plays a fundamental role in the availability of micronutrients and their behavior at a soil-plant level. The aims of this paper were: a to establish the relationship between soil properties and micronutrient dynamics within

  15. Iron overload and genotype 3 are associated with liver steatosis in chronic hepatitis C Sobrecarga de hierro y genotipo 3 se asocian a la presencia de esteatosis en la hepatitis C

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    L. I. Fernández Salazar

    2004-12-01

    excluyeron pacientes con otros virus. Se revisaron las biopsias hepáticas de forma protocolizada. Se obtuvieron los datos epidemiológicos, analíticos y virológicos. La talla y el peso de los pacientes se recogieron en el momento de la biopsia hepática. Se estudió la asociación estadística de las variables cualitativas y cuantitativas con la presencia de esteatosis y se realizó un análisis multivariante. Resultados: se identificó esteatosis en el 52% de las biopsias. No hubo asociación estadísticamente significativa con edad, sexo, vía de contagio, tiempo de evolución, ingesta de alcohol, presencia de enfermedades asociadas, índice de masa corporal, glucosa, triglicéridos, colesterol, AST, ALT, GGT, FA, bilirrubina, carga viral. Se asoció a mayor sideremia, IST y ferritina. Se demostró asociación con el genotipo 3. La esteatosis se asoció a necrosis piecemeal, degeneración hepatocelular, hiperplasia de células de Kupffer, hierro hepático y fibrosis portal. El hierro hepático, la hiperplasia de las células de Kupffer y el genotipo 3 se asociaron de manera independiente a la esteatosis hepática. Conclusiones: la esteatosis en la hepatitis C se asocia a la infección por genotipo 3, a la hiperplasia de las células de Kupffer y a sobrecarga de hierro. También se asocia a mayor inflamación y fibrosis por lo que debe ser considerada factor agravante.

  16. Estudio del efecto de la adición de distintos mineralizadores en la síntesis cerámica del pigmento rosa coral de hierro-circón

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    Llusar, M.

    1999-06-01

    Full Text Available The addition of several mineralizing agents (alkaline or alkaline-earth halides, KNO3, etc. in the traditional ceramic synthesis of the “coral pink” iron-zircon (Fe-ZrSiO4 ceramic pigment has been analysed, using two different Fe precursors (sulphate and goethite. FeSO4.7H2O employment as Fe precursor allows us to obtain a better reddish colour than with goethite (FeO(OH. Results let us to classify the studied mineralisers in two major groups: i primary or zircon-forming mineralisers, which activate somehow zircon formation with a good occlusion efficiency of hematite into the zircon matrix (NaF, NaCl and BaF2 when using FeSO4 and Na2SiF6 and NaAl3F6 with goethite,. and ii secondary or modifying mineralisers, that have a collateral effect on the pigment synthesis regulating both hematite crystallisation and occlusion (KNO3, Na2SiF6 and NaAl3F6 with FeSO4 and KI and KNO3 with goethite. With regard to the color yield, those compositions mineralised with the binary systems NaF-Na2SiF6, NaF-NaAl3F6 and NaF-KNO3 have been found to develop the best red color.

    Se ha analizado el efecto de la adición de distintos agentes mineralizadores (haluros alcalinos y alcalino-térreos, KNO3, etc. en la síntesis cerámica tradicional del pigmento rosa coral de hierro-circón (Fe-ZrSiO4, usando dos precursores diferentes para el hierro (sulfato y goetita. El empleo de FeSO4.7H2O como fuente de hierro permite obtener mejores coloraciones rojizas que con goetita (FeO(OH. Los resultados obtenidos permiten clasificar a los distintos mineralizadores ensayados en dos grandes grupos: i mineralizadores primarios o “formadores de circón”, los cuales permiten activar el desarrollo del circón con una buena eficiencia en el encapsulamiento de la hematita en los cristales de circón (NaF, NaCl y BaF2 con FeSO4, y Na2SiF6 y NaAl3F6 con goetita, y ii mineralizadores “secundarios o coadyuvantes”, con un efecto colateral sobre la síntesis del pigmento

  17. Iron zircon pigment synthesis: Proposal of a mixing index for the raw materials mixtures; Síntesis del pigmento de hierro-circón: Propuesta de un índice de mezclado para mezclas de materias primas

    Energy Technology Data Exchange (ETDEWEB)

    Zumaquero, E.; Ortsb, M.J.; Sanz, V.; Mestre, S.

    2017-11-01

    Iron zircon coral pigments are very interesting from an industrial point of view because of their high colouring power and their stability at high temperatures. However, the pigment's synthesis is particularly troublesome due to its specific reaction mechanism. As an encapsulated pigment it becomes very important how the raw materials are distributed in the reaction mixture. To evaluate the effectiveness of the mixing process, it would be convenient to define a parameter, that is the mixing index, to estimate the degree of homogeneity of the system. In the current investigation, a mixing index is proposed derived from the power spectrum of Fourier transform of scanning electron microscope (SEM) images of the raw material mixture. Concretely, the number of pixels in a certain range of values in the image of the power spectrum, seems to behave relatively well as mixing index. This index allows us to distinguish between samples with different zirconia and iron oxide used as precursors. The proposed mixing index seems to be related to the colouring power of the final pigment when the synthesis generates enough zircon to encapsulate hematite particles. [Spanish] Los pigmentos coral de hierro-circón son muy interesantes desde el punto de vista industrial ya que n un alto poder colorante y estabilidad a altas temperaturas. Sin embargo, la síntesis del pigmento es particularmente problemática debido a su mecanismo de reacción. Al tratarse de un pigmento encapsulado, resulta fundamental cómo se encuentran distribuidas las materias primas en la mezcla de reacción. Para evaluar la efectividad del proceso de mezclado, es conveniente definir un parámetro, que es el índice de mezclado, para estimar el grado de homogeneidad del sistema. En el presente trabajo de investigación se propone un índice de mezclado basado en el espectro de potencia de la transformada de Fourier de imágenes obtenidas con el microscopio electrónico de barrido de las mezclas de materias

  18. La anemia por deficiencia de hierro en la población infantil de Cuba. Brechas por cerrar Iron deficiency anemia in the child population of Cuba. Gaps to be bridged

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    Gisela Pita-Rodríguez

    2011-06-01

    Full Text Available La anemia es un problema de salud mundial que afecta tanto a los países desarrollados como a aquellos en desarrollo. Sus causas pueden ser multifactoriales y frecuentemente pueden coexisitir varias de ellas; la principal es la baja ingestión de alimentos con fuentes adecuadas de hierro, tanto en cantidad como en calidad. En Cuba se está trabajando desde el año 1987 en el desarrollo de programas de intervención para la prevención de la anemia por deficiencia de hierro en la población, pero a pesar de todo el esfuerzo, no se han obtenido los impactos esperados, y existen diversos factores que pueden estar incidiendo en ello y que pueden sinergizarse. Evidencias científicas nacionales muestran que la baja prevalencia de lactancia materna, el escaso consumo de frutas y vegetales y la deficiencia vitamínica, ejercen influencia en la prevalencia de la anemia en Cuba. El parasitismo intestinal y la infección con H. pylori no están asociados con la prevalencia de anemia en el país. La obesidad e inflamación crónica a bajo tenor requerirían de estudios epidemiológicos que describan las posibles asociaciones entre estos factores.Anemia is a global health problem affecting both developed and developing countries. The causes of anemia may be multifactorial, and several of them are often present at the same time. The main cause of anemia is the low intake of foods with adequate sources of iron both in quantity and quality. Work is being done in Cuba since the year 1987 aimed at developing intervention programs for the prevention of iron deficiency anemia in the population, but despite the great effort, the expected impact has not been achieved, due to the combined influence of various factors. National scientific evidence shows that the low incidence of breastfeeding, the low intake of fruits and vegetables, as well as vitamin deficiency, have an influence on the prevalence of anemia in Cuba. Neither intestinal parasitism nor infection with H

  19. Efficacy of intravenous iron in treating iron deficiency anaemia in patients with inflammatory bowel disease: Are there predictors of response? Eficacia del hierro intravenoso en el tratamiento de la anemia ferropénica en pacientes con enfermedad inflamatoria intestinal: ¿Existen factores predictivos de respuesta?

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    Rocío Ferreiro Iglesias

    2011-05-01

    Full Text Available Introduction: in inflammatory bowel disease (IBD iron deficiency anaemia (IDA is a very common disorder. Until recently, oral iron has been the mainstay therapy, nevertheless it has been associated with intolerance and noncompliance. Therefore, the goal of our study was to evaluate the efficacy of intravenous iron in IDA in IBD patients and the secondary aim was to investigate whether other potential factors could influence in the response to the treatment. Design: an open-label, prospective, consecutive, single centre study. Material and methods: we performed our study in patients with ulcerative colitis (UC or Crohn's disease (CD with severe anaemia or intolerance with oral iron. All of them received intravenous sacarose iron and did biochemistry profile with haemoglobin (Hb. Moreover, the correlation with other variables was studied: age, sex, smoking habit, IBD type, previous surgery and type of surgery and other treatments. Response was defined as Hb increase of ≥ 2 g/dL or normalization of the levels. Results: fifty-four patients were included into the study, 34 (63% with UC y 20 (37% with CD, 18 (33.3% men and 36 women (66.6% and the average was 48 ± 14 years. The total proportion of responders was 52% (SD ± 05; 43% of the patients reached Hb ≥ 2 g/dl and y 9% of them normalized Hb. Only the utilization of 5-ASA was associated with low response to iron treatment (p Introducción: la anemia por déficit de hierro es un problema frecuente en la enfermedad inflamatoria intestinal (EII. Un número no despreciable de pacientes no responde o presenta intolerancia al hierro oral. El objetivo de nuestro estudio es evaluar la eficacia del hierro sacarosa intravenoso (Venofer® en los pacientes con EII así como los potenciales factores que pueden influir en la respuesta al mismo. Diseño: estudio abierto, unicéntrico y con una inclusión consecutiva de casos. Material y métodos: se incluyeron pacientes con colitis ulcerosa (CU y enfermedad

  20. Digestión en horno de microondas para determinación de contenido de hierro y zinc totales en alimentos Microwave digestion for determination of iron and zinc content of total food

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    Paulina Silva Trejos

    2012-11-01

    Full Text Available En el presente estudio se optimizó el procedimiento de digestión de alimentos por medio de un horno de microondas, para cuantificar el hierro y el zinc totales en diferentes matrices por espectroscopía de absorción atómica. Se analizó la cantidad óptima de HNO3 concentrado al 65% para digerir determinada masa de muestra por evaluación del porcentaje de recuperación obtenido con diferente cantidad de HNO3. Los resultados no difieren de los obtenidos por los métodos recomendados oficialmente de digestión ácida en sistemas abiertos y de calcinación.In this study, the procedure was optimized digestion of food by means of a microwave oven, to quantify the total iron and zinc in different matrices by atomic absorption spectroscopy. We analyzed the optimal amount of 65% concentrated HNO3 to digest sample mass determined by evaluating the percent recover y obtained with different amounts of HNO3.The results are similar to those obtained by the methods recommended officially acid digestion in open systems and calcination.

  1. La pantalla feminista: feminidad sufragista y masculinidad hegemónica. Análisis cinematográfico: Ángeles de Hierro (2004 y Las Sufragistas (2015

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    Iván Gómez Beltrán

    2016-06-01

    Full Text Available La cinematografía de los últimos años ha prestado especial atención a determinados procesos de la Historia del feminismo, uno de estos “hechos” lo constituye el sufragismo. A lo largo del texto se pretenderá ahondar en la politización de los mensajes fílmicos y por tanto en su comprensión/recepción como discurso político al alcance del público contemporáneo así como instrumentos productivos de una representación determinada de los géneros y sus alteridades. Todo ello sin olvidar los “efectos” –en tanto agentes culturales- que pueden producir en la sociedad. Para ello se utilizarán dos películas del cine mainstream contemporáneo Ángeles de Hierro (2004 y Las Sufragistas (2015 con la intención de analizar cómo la narración fílmica sirve a los intereses discursivos de la desmitificación de las mitologías antisufragistas así como al despliegue de la alteridad femenina sufragista y la comprobación de los posibles cambios y resistencias en el seno de la masculinidad.

  2. Del desarrollismo al (neoextractivismo (1969-2017. Auge, decadencia y resurgimiento de la minería del hierro en Sierra Grande, provincia de Río Negro (Argentina

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    Sebastián Gómez Lende

    2017-09-01

    Full Text Available Aunque en la Argentina la problemática del avance del extractivismo y la minería metalífera ha sido ampliamente debatida en tiempos recientes, en el pasado esta última actividad ha sido clave respecto de la configuración de la matriz productiva de ciertas provincias. Tal es el caso del complejo minero-fabril de Sierra Grande (provincia de Río Negro, única explotación metalífera surgida en el país por iniciativa del Estado nacional. Este trabajo analiza el auge, decadencia y resurgimiento de la minería del hierro en Sierra Grande, a la luz del contexto impuesto por proyecto desarrollista estatal primero (1969-1992, la fase neoliberal después (1993-2004, y finalmente el modelo (neoextractivista (2005-2017. Asimismo, se demuestra que este último período ha sido escenario del despliegue de variadas formas de acumulación por desposesión, como la privatización y extranjerización de bienes comunes, la configuración de enclaves exportadores, la superexplotación del trabajo, la expropiación político-económica y la desapropiación socio-ecológica.

  3. La aldea del Hierro Inicial del Cerro de San Vicente (Salamanca, España: Resultados de las excavaciones entre 1990 y 2006 a la luz de algunos debates actuales

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    Antonio BLANCO-GONZÁLEZ

    2017-01-01

    Full Text Available Este artículo recoge algunos de los principales resultados de las excavaciones arqueológicas efectuadas entre 1990 y 2006 en el yacimiento de la Primera Edad del Hierro (800-400 cal AC del Cerro de San Vicente (Salamanca. El trabajo aborda dos cuestiones mal conocidas, centrándose en las últimas ocupaciones del asentamiento, por ser las mejor investigadas: a los procesos de formación y acumulación de restos en una aldea con arquitectura de barro; y b una caracterización social de sus habitantes. La anatomía interna de este asentamiento muestra la persistencia de usos y la superposición de desechos y estructuras. Las viviendas carecen de enseres domésticos, aparecen colmatadas con adobes y en ocasiones incendiadas. Respecto a la organización social, se detectan síntomas de división interna: las casas con atrio y sus dependencias auxiliares se cercan. Las estrategias agrarias complejas constatadas pudieron haber facilitado la acumulación de riqueza por algunas familias, dentro de una organización social heterárquica.

  4. Thermodynamic Properties of Alloys of Iron and Silicon; Proprietes Thermodynamiques des Alliages Fer-Silicium; Termodinamicheskie svojstva splavov zheleza s kremniem; Propiedades Termodinamicas de las Aleaciones de Hierro y Silicio

    Energy Technology Data Exchange (ETDEWEB)

    Vecher, R. A.; Gejderih, V. A.; Gerasimov, Ja. I. [Moskovskij Gosudarstvennyj Universitet Im.M.V. Lomonosova, Moskva, SSSR (Russian Federation)

    1966-01-15

    -Harpoon-Over-Leftwards-Harpoon {alpha}' est une veritable transformation de phase. La region a deux phases est plus large que ne semble l'indiquer le diagramme d'equilibre (etabli d'apres les valeurs publiees). L'activite du fer en solution liquide calculee a partir de celle du fer en solution solide est en bon accord avec les valeurs trouvees par Chipman. (author) [Spanish] El diagrama de equilibrio Fe-Si es muy complejo. A 1000 Degree-Sign K se observa la presencia de las fases siguientes: FeSi{sub 2}({beta}), FeSi y soluciones solidas de silicio en hierro {alpha} and {alpha}'. Los autores midieron las fuerzas electromotrices de las celdas electroquimicas: Fe|Fe{sup 2+} , KI + Nal|Fe-Si at 600-800 Degree-Sign C fundidos Las aleaciones se prepararon a partir de componentes puros por pulvimetalurgia y se sometieron a un recocido prolongado. Los autores estudiaron diez aleaciones con un contenido de silicio comprendido entre 85% y 4%, situadas en todas las fases del diagrama de equilibrio a 1000 Degree-Sign K. Calcularon los valores integrales de {Delta}G, {Delta}H y {Delta}S correspondientes a la formacion de los siliciuros FeSi{sub 2}({beta}), FeSi y Fe{sub 3}Si a la temperatura media del intervalo experimental (1000 Degree-Sign K), asi como (utilizando el calor especifico de los siliciuros de hierro y del silicio) a 298, 1188 y 1798 Degree-Sign K. Los calores de formacion de los mencionados siliciuros a 298 Degree-Sign K ascienden a -19,4, -17,6 y -22,4 kcal/mol, respectivamente. Los datos publicados permiten calcular el calor de formacion del FeSi{sub 2,33} - ({alpha}-leboita) a 298 Degree-Sign K, que es igual a -14,4 kcal/mol. Los calores calculados por los autores son superiores a los datos experimentales de Corber y de Olsen en 1,5 - 3 kcal. Por otra parte, los calores de mezcla, calculados para las aleaciones liquidas, concuerdan satisfactoriamente con los datos publicados. Los datos obtenidos pueden explicarse como un resultado de la modificacion que sufre el caracter del enlace en los

  5. Aplicación de tratamiento electroquímico a baja intensidad de corriente para la extracción de cloruros en objetos arqueológicos de hierro de procedencia subacuática. Observación de la evolución de fases mineralógicas mediante XRD-Rietveld

    Directory of Open Access Journals (Sweden)

    Bethencourt, M.

    2004-12-01

    Full Text Available With the purpose of optimising a suitable methodology for the conservation of an archaeological object of iron, a low current intensities electrolytic treatment has been applied, to a piece of cast iron, proving to be effective in the extraction of chloride ions from the structure of akaganeite, principal corrosion product of iron in the marine medium. The monitoring of the electrolytic treatment has been proven by applying the "Rietveld" method to the patterns XRD of samples extracted from the corroded surface before and after the treatment. This method has permitted the unequivocal determination of the akaganeite and its chemical composition. This identification has been corroborated by means of SEM and EDS. After the electrolytic treatment, akaganeite was not present in the sample.

    Con objeto de optimizar una metodología adecuada para la conservación de una pieza de hierro arqueológico de fundición, se ha aplicado un tratamiento electrolítico a bajas intensidades de corriente, demostrando su efectividad en la extracción de iones cloruro de la estructura de akaganeita, principal producto de corrosión del hierro en medio marino. La monitorización del proceso se ha comprobado aplicando el método Rietveld a los patrones XRD de muestras extraídas de la superficie corroída antes y después del tratamiento. Este método ha permitido la determinación inequívoca de la akaganeita y la composición química de este oxihidróxido de hierro no estequiométrico. Dicha identificación se corrobora mediante SEM y EDS. Después del tratamiento electrolítico la akaganeita no está presente en la muestra.

  6. The determination of the thermodynamic activity of antimony in alpha-iron; Determination de l'activite thermodynamique de l'antimoine dans le fer alpha; Opredelenie termodinamicheskoj aktivnosti sur'my v al'fa-zheleze; Determinacion de la actividad termodinamica del antimonio en el hierro alfa

    Energy Technology Data Exchange (ETDEWEB)

    Tomilin, I A

    1962-01-15

    des divergences positives par rapport a l'etat parfait lorsque les concentrations d'antimoine present sont peu importantes. L'auteur a calcule la quantite de chaleur necessaire pour dissoudre l'antimoine dans le fer, ainsi que l'excedent d'entropie molaire partielle d'apres la temperature d'activite. Il s'est servi des resultats obtenus pour determiner avec precision la ligne qui marque la limite de solubilite de l'antimoine dans le fer alpha. Etant donne que les ferroalliages d'antimoine avaient ete obtenus par voie de saturation de diffusion, et non par refroidissement a partir de l'etat liquide, il n'y a pas eu de liquefaction. L'auteur a donc pu determiner d'une facon sure la constante du reseau des alliages et la relation entre cette constante et la concentration de l'antimoine. La limite de solubilite determinee d'apres les donnees radiographiques correspond a celle que l'on obtient en employant l'antimoine-124. (author) [Spanish] La memoria propone un metodo para determinar la actividad termodinamica del antimonio disuelto en el hierro alfa, que se basa en el estudio de la reparticion de este metal entre dos fases: plomo liquido y hierro solido. El metodo permitio observar que las soluciones solidas de antimonio en hierro se desvian en sentido positivo del estado ideal. Las soluciones de este elemente en el hierro obedecen a la ley de Henry en un intervalo muy extenso de concentraciones. Los experimentos especiales realizados para estudiar la reparticion del antimonio entre el plomo y el hierro en estado liquido han demostrado que, en estado liquido, el sistema hierro-antimonio se caracteriza por su desviacion positiva respecto del estado ideal cuando la concentracion del segundo elemento es baja. Los autores calcularon el calor necesario para la disolucion del antimonio en el hierro alfa, y el incremento de entropia molar parcial a partir de la temperatura de activacion. Los resultados obtenidos han servido para establecer con precision el limite de

  7. Biosíntesis de dextranos de alto peso molecular mediante la inoculación con Leuconostoc Mesenteroides, var. Mesenteroides (atcc 10830 de jugos residuales de la agroindustria de la piña: síntesis y caracterización de hierro-dextranos

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    José Roberto Vega Baudrit

    2013-01-01

    Full Text Available En este trabajo se muestran los estudios realizados para obtener dextranos a partir de desechos de la agroindustria de piña. La fermentación se llevó a cabo en un biorreactor (10 L, se inoculó con un cultivo de Leuconostoc mesenteroides, var. mesenteroides (ATCC 10830. Se centrifugó y se precipitó y purificó con etanol. Fue caracterizado por medio de viscosidad, peso molecular y grupos funcionales por espectroscopía infrarroja. Este dextrano fue tratado con el fin de obtener hierro-dextranos.

  8. Granulometría, morfometría y mineralogía de polvo atmosférico que entra a la cuenca canaria: evidencia de retención de partículas de hierro en la capa de mezcla

    OpenAIRE

    Jaramillo-Vélez, Alfredo; Menéndez, Inmaculada; Alonso, Ignacio; Mangas, José; Hernández-León, Santiago

    2016-01-01

    El polvo atmosférico juega un papel importante en el clima y en los procesos oceánicos, particularmente la deposición del polvo sahariano es de suma importancia en la corriente canaria debido a que contiene minerales de hierro que actúan como fertilizante del océano. En este trabajo las partículas de polvo fueron caracterizadas mediante granulometría, morfometría y mineralogía, usando procesamiento de imágenes, microscopia electrónica (SEM-EDS). El polvo analizado en este estudio fue generado...

  9. Iron, zinc, copper and magnesium nutritional status in Mexican children aged 1 to 11 years Estado nutricio de hierro, zinc, cobre y magnesio en niños mexicanos de 1 a 11 años de edad

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    Ma. del Carmen Morales-Ruán

    2012-04-01

    Full Text Available OBJECTIVE: To describe the micronutrient nutritional status of a national sample of 1-11 year old Mexican children surveyed in 2006 in National Health and Nutrition Survey (ENSANUT 2006 and their association with dietary and sociodemographic factors. MATERIALS AND METHODS: Serum samples were used (n=5 060 to measure the concentrations of ferritin, transferrin receptor, zinc, copper and magnesium. RESULTS: Prevalence of deficiencies in 1-4 and 5-11y old children were for iron (using low ferritin 26.0 and 13.0%; zinc, 28.1 and 25.8%, respectively; and copper, ≈30% in both age groups. Magnesium low serum concentrations (MLSC, were found in 12.0% and 28.4% of the children, respectively. Being beneficiary of Liconsa (OR=0.32; C.I.95%, 0.17-0.61 or belonging to higher socioeconomic status (OR=0.63; C.I.95%, 0.41-0.97 were protective against iron deficiency. Increasing age (OR=0.59; C.I.95%, 1.19-1.32 and living in the Central Region (OR=0.59; C.I.95%, 0.36-0.97 were protective against MLSC. CONCLUSIONS: Deficiencies of iron and zinc are serious public health problems in Mexican children.OBJETIVO: Describir el estado nutricio de micronutrimentos en niños de 1-11 años de edad de la Encuesta Nacional de Salud y Nutrición 2006 y su asociación con factores dietéticos y sociodemográficos. MATERIAL Y MÉTODOS: Se usaron muestras séricas (n=5060 para medir las concentraciones de ferritina, receptor de transferrina, zinc, cobre y magnesio. RESULTADOS: La prevalencias de deficiencias en niños de 1-4 y de 5 a 11 años fueron para ferritina, 26.0 y 13%; zinc, 28.1 y 25.8% respectivamente y cobre ≈30% en ambos grupos. Las concentraciones bajas de magnesio (CBM fueron 12.0 y 28.4%, respectivamente. Ser beneficiario de Liconsa (RM=0.32; IC 95%: 0.17-0.61 y pertenecer al nivel socioeconómico alto (RM=0.63; IC, 95%: 0.41-0.97 fueron protectores para deficiencia de hierro. La edad (RM=1.26; IC, 95%: 1.19-1.32 y vivir en la región Centro (RM=0.59; IC, 95

  10. Transferência de oxigênio em reatores de leito fluidizado com circulação em tubos concêntricos em meios bifásico e trifásico com variação da relação entre diâmetros Oxygen transfer in two and three-phase internal-loop airlift reactor with riser diameter variation

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    Leandro Santos de Araújo

    2010-09-01

    Full Text Available A eficiência do reator de leito fluidizado com circulação em tubos concêntricos depende das condições hidrodinâmicas que influem na transferência de oxigênio ao biofilme. Este trabalho investigou a influência da relação entre diâmetros dos tubos e da concentração de meio suporte (areia, sobre o coeficiente global de transferência de oxigênio (K La. Os ensaios - em reatores de 2,6 m de altura, com diâmetro externo de 250 mm e internos de 100, 125, 150 e 200 mm - empregaram vazões de ar até 2.500 L.h-1 e concentrações de até 150 g.L-1 de areia. O K La aumentou ligeiramente com 30 g.L-1 e diminuiu para concentrações maiores, confirmando relatos da literatura em condições semelhantes. Um modelo para K La em meio bifásico foi ajustado para as diversas relações ensaiadas entre a área externa e a interna, postulando-se uma redução na razão entre a transferência na fase líquida e o diâmetro da bolha com o aumento da vazão de ar.The efficiency of the concentric tubes internal-loop airlift reactor depends on the hydrodynamic conditions that affect oxygen transfer to the biofilm. This work studied the effects of the relation between diameters of the tubes and of the carrier (sand concentration on the global oxygen transfer coefficient (K La. The tests - in 2,6 m high reactors with 250 mm external diameter and 100, 125, 150 and 200 mm internal diameters - were performed with air flow taxes up to 2,500 L.h-1 and sand concentrations up to 150 g.L-1. The K La increased slightly for 30 g.L-1 and decreased for higher concentrations, in accordance with related data for similar conditions. A model for K La in biphasic medium was fitted embracing all the external/internal area relationships tested, based on the reduction of the liquid phase transfer coefficient and the bubble diameter ratio with increasing air flow rates.

  11. Junta de soldadura disímil de la aleación hk – 40 y del hierro fundido 24//Dissimilar welding joints of the alloy hk - 40 and of the cast iron 24

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    Tomás Fernández‐Columbié

    2014-05-01

    Full Text Available El objetivo del trabajo es establecer el comportamiento microestructural de una unión soldada disímil en una aleación HK 40 y el hierro fundido 24, la cual se realiza en equipo que prestan servicios en la industria del níquel y que por las características de la unión, surgen en el mismo problema de agrietamiento. Se realizó una caracterización química de ambas aleaciones, luego por el proceso demecanizado se prepararon un total de nueve muestras, las que fueron soldada por proceso manual por arco eléctrico, los electrodos revestidos empleados fueron el E 312–16, el UTP 65 y el Castell Xiron 244, demostrándose en el análisis microestructural y en el diagrama de Schaeffler, que la disposición de la unión con el electrodo E 312–16 provoca la aparición de estructura interdendritica con origen a la fundición blanca, siendo más favorable la unión con el electrodo UTP 65. Se le realizó el análisis de microdureza en cada unión.Palabras claves: disímil, aleación, agrietamiento, soldadura, electrodos._____________________________________________________________________________AbstractIt is paper have the objective to establish the behaviour microstructure of an union welded dissimilar in an alloy HK 40 and the cast iron 24, which is carried out in team that you lend services in the industry of the nickel and that for the characteristics of the union, they arise in the same cracking problem. He was carried out a chemical characterization of both alloys, then for the process ofautomated got ready a total of nine samples, those that were welding for process shield for electric arch (SMAW, the electrodes lined employees were the E 312 - 16, the UTP 65 and the Castell Xiron 244, being demonstrated in the analysis microstructure and in the diagram of Schaeffler that the disposition of the union with the electrode E 312 - 16 cause the appearance of structure inter dendritewith origin to the white foundry, being more available the union

  12. Modificación superficial de aceros y hierros fundidos mediante láser de Nd: YAG. // Steels and cast irons superficial modification by means of laser Nd: YAG.

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    R. Sagaró Z.

    2001-10-01

    Full Text Available Se presentan los resultados de los autores en el tratamiento térmico superficial con técnica láser (TTSL. Con el empleo deun láser de Nd: YAG se procedió al endurecimiento superficial de los aceros AISI 1045, W1, W112 y hierros fundidos detipo laminar y nodular. Los autores prestan atención a las rutas de endurecimiento superficial atendiendo a los parámetrosoperacionales del láser: potencia incidente en la zona de interacción (P y la velocidad de barrido del haz de láser (V. Deigual forma se establecen valoraciones acerca de las estructuras metalográficas obtenidas. En todos los casos se reportanvalores de microdureza Vickers que oscilan entre los 500-900 HV (incrementos de 3-4 veces respecto al substratooriginal. Los resultados obtenidos permiten establecer en todos los casos experimentados que el incremento de lavelocidad de barrido provocó una disminución de la profundidad de la capa endurecida. Las experiencias del TTSL en losaceros ensayados muestran una tendencia a la disminución de la profundidad del endurecimiento con el incremento delcontenido de carbono.Palabras claves: Endurecimiento superficial, parámetros de operación de láser., microdureza, profundidadde capa endurecida, de fallo, vibraciones.____________________________________________________________________________AbstractThis paper expose the experiences of researchers on the laser surface heat treatment. The hardening of AISI 1045, W1,W112 steels and cast irons flake and nodular was carried out by using a Nd: YAG laser. Operation parameters of laser, likebeam power (P and traverse speed of the laser spot (V are closely with hardening depth . Authors present some analysesabout metallographic studies. In all cases are reported Vickers microhardness about 500-900 HV (three or four times higherthan original substrates. Relations between microhardness and depth of hardening are presented for the processedmaterials. Experimental results showed that the increased

  13. Efecto de la serpentina en la formación de fases mineralógicas y su relación con la resistencia mecánica en sinterizados de mineral de hierro

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    Bedolla, E.

    1995-12-01

    Full Text Available The influence of microstructures formed by serpentine addition on mechanical strength is investigated. It was found that the microstructure formed depends mainly on firing temperature, basicity and serpentine percent. The mineralogical phases present were quantified by the point-count method. The addition of serpentine on acid briquettes (CaO/Si O2 = 0.3, mainly on those fired at 1,275, 1,300 and 1,325 °C, leads to the formation of magnesio-ferrite that diminishes the mechanical strength of fired briquettes, and at the temperature of 1,250 °C the mechanical strength decreases because of the presence of glassy slags. On the other hand, the addition of serpentine on basic briquettes (CaO/Si O2 = 1.2 leads to the formation of olivines and ferrites that improve the mechanical strength of fired briquettes.

    Se estudia la influencia de las microestructuras formadas sobre la resistencia mecánica de mineral de hierro aglomerado con serpentina. Se deduce que la microestructura formada depende de la temperatura de sinterización, de la basicidad y del valor porcentual de serpentina, principalmente. Las fases mineralógicas presentes se cuantificaron utilizando la técnica de conteo por puntos. En briquetas acidas (CaO/SiO2 = 0,3 sinterizadas a 1.275, 1.300 y 1.325 °C, se encontró que la serpentina induce la formación de magnesio-ferritas que traen, como consecuencia, una disminución de la resistencia mecánica, mientras que, a la temperatura de sinterización de 1.250 °C, la aparición de escorias vítreas es la causa principal de la disminución de resistencia. En el caso de briquetas básicas (CaO/SiO2 = 1,2, la adición de serpentina produce la formación de olivinas y calcio-ferritas que originan un aumento de la resistencia mecánica de los sinterizados.

  14. Producción de hierros nodulares ferríticos directamente de fundición partiendo de chatarra de acero de alto manganeso // Production of ferrítics nodular irons directly from foundry leaving of high manganese scrap steel

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    C. DeFranch

    1999-07-01

    Full Text Available La producción de hierros nodulares con matriz ferrítica es lograda normalmente con el uso de arrabios especiales con bajoscontenidos de elementos formadores de carburos, o mediante largos y costosos tratamientos térmicos. Estos arrabios tienenaltos precios, por lo que se hace necesario la búsqueda de variantes más económicas para la producción de este tipo dematerial. El objetivo de este trabajo es la obtención de dicho material usando como carga chatarra de acero, la cual tiene unprecio mucho mas bajo.La estructura de la matriz en el hierro nodular, depende de su composición química, su velocidad de enfriamiento, así como dela forma y cantidad de nódulos de grafito. Cuando lo que se desean son matrices ferríticas se deben mantener los elementosperlitizantes en contenidos lo más bajo posible para desfavorecer de esta forma la solidificación de acuerdo al diagramametaestable.El uso de chatarra plantea el problema de los niveles de manganeso presentes en la misma (generalmente entre 0.6 y 0.8%. Elmanganeso, que es un elemento perlitizante evita la obtención de altas elongaciones ya que la matriz nunca seríacompletamente ferrítica. Es por esto que si se desea usar chatarra de acero como material de carga sea necesario el estudio deformas de eliminarlo del baño.Para la eliminación del manganeso existen diversas referencias en la literatura a procesos desarrollados a base de cloro,oxígeno, sulfatos, óxido de hierro, y procesos con el uso de hornos al vacío.En este trabajo la eliminación del manganeso mediante el uso de óxido de hierro, Sulfato de sodio, y PVC. ha sido investigada,llegando a soluciones factibles para la producción de este tipo de hierro.El primero de los tres métodos ha demostrado ser el más factible ya que el segundo aumenta el contenido de azufre en el baño,requiriendo una desulfuración previa al tratamiento de esferoidización y el tercero de los métodos desprende una gran cantidadde gases da

  15. Food Consumption and Iron Intake of Pregnant and Reproductive Aged Women Consumo alimentar e ingestión de hierro por mujeres embarazadas y en edad reproductiva Consumo alimentar e ingestão de ferro de gestantes e mulheres em idade reprodutiva

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    Ana Paula Sayuri Sato

    2010-04-01

    Full Text Available This study compares the eating habits and consumption of natural and fortified iron sources in pregnant and reproductive aged women. This cross-sectional study was developed in a health center located in São Paulo, SP, Brazil. We studied 61 women, of which 30 were pregnant. A food frequency questionnaire and a 24-hour recall instrument were used. The main natural sources of iron were beans and greens, although fortified foods were also an important source. There was little statistically significant difference between the food consumption of pregnant and non-pregnant women. Inadequate intake of iron, folate and calcium was observed in both groups. Non-pregnant women meet the iron recommendation, considering the iron added in fortified foods, though pregnant women do not. These results suggest the need for mixed strategies: food fortification, iron supplements for pregnant women and nutritional instruction for women in general.Comparar la práctica alimentar y el consumo de alimentos fuentes de hierro, naturales y fortificados, de mujeres en edad reproductiva, gestantes o no, constituye el objetivo de esta investigación. Se trata de un estudio transversal, desarrollado en un centro de salud del municipio de Sao Paulo, en el cual participaron 61 mujeres, siendo 30 gestantes. Se utilizó un cuestionario de frecuencia de consumo alimentar y un recordatorio de 24h. Las principales fuentes naturales de hierro fueron frijoles y hojas verdes. Alimentos fortificados también tuvieron participación importante. Hubo una pequeña diferencia estadísticamente significativa entre el consumo alimentar de las gestantes y no gestantes. Se observó inadecuación del consumo de hierro, folato y calcio en los dos grupos. Las mujeres no gestantes atenderían la demanda de hierro, considerándose el adicional recomendado para la fortificación de las harinas, sin embargo, las gestantes no. Hay necesidad de implementar estrategias combinadas: fortificación de los

  16. Un exponente de gestión económica de la «fidalguía» gallega y de producción de hierro en la montaña lucense. La herrería de Quinta durante el Antiguo Régimen

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    Vítor Manuel MIGUÉS

    2009-11-01

    Full Text Available Tradicionalmente vinculadas a la percepción de rentas agrarias, las economías señoriales en Galicia fueron frecuentemente observadas desde tal atalaya. Es por eso por lo que estrategias diferentes de comportamiento económico son tan desconocidas como casi inabordadas. Esto, si cabe, se acentúa aún más en el caso de la producción de hierro, actividad desarrollada a lo largo de los siglos en pequeñas y diseminadas unidades de producción conocidas comúnmente en Galicia como «ferrarías», y tradicionalmente desconocidas no sólo como integrantes de economías señoriales de más amplio fuste, sino como representantes del débil sector industrial del Antiguo Régimen.

  17. El péptido ? A [25-35] y el hierro promueven apoptosis en linfocitos por un mecanismo de estrés oxidativo: contribución del H202,, caspasa 3, fn- kb, p53 y c-Jun

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    Marlene Jiménez

    2001-04-01

    Full Text Available El depósito del beta-amiloide (βA en las placas neuríticas es
    uno de los principales marcadores neuropatológicos de la enfermedad de Alzheimer (EA. Estudios in vitro han demostrado que el fragmento βA25-35, el cual contiene la secuencia funcionalmente citotóxica del péptido amiloide, induce neurotoxicidad y muerte celular por apoptosis (1. A pesar de las intensas investigaciones, no se ha dado una descripción completa de la cascada de eventos moleculares que conducen a muerte inducida por βA25-35 en un modelo celular único. Por lo tanto, nuestro objetivo principal es evidenciar una cascada de eventos moleculares ordenados inducidos por el bA25-35 y el hierro en un modelo celular.

  18. Validación de la metodología analítica para la cuantificación de hierro por espectroscopia de absorción atómica de llama en alimentos de la canasta básica costarricense

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    Paulina Silva Trejos

    2009-01-01

    Full Text Available Se validó la metodología analítica para la determinación de hierro en alimentos de la canasta básica del costarricense por espectroscopia de absorción atómica con llama. La digestión de las muestras se realizó en recipientes cerrados, con horno de microondas con HNO3 al 65% m/m, para muestras de 0,5 g, dependiendo del tipo de alimento; las cantidades óptimas de ácido nítrico variaron de 6 a 10 mL, obteniéndose porcentajes de recuperación que variaron de 90,0±0,5% a 106,0±0,5%. El ámbito de linealidad óptimo que se obtuvo fue de 0,05 m/L a 6,0 mg/L, con un coeficiente de correlación de 0,9991. Los límites de detección y cuantificación reportados fueron de 0,006 mg/L y 0,009 mg/L, respectivamente. La veracidad se determinó utilizando un patrón certificado de la NIST, SRM 1846 Infant Formula, con un valor reportado para hierro de 63,1±4,0 mg/kg, el valor obtenido fue de 63,8 mg/L, con un porcentaje de error de 1,1%.

  19. Proceso de molturación mecánica en medio seco, húmedo y criogénico de polvo de hierro dúctil nanoestructurado

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    Cinca, N.

    2011-06-01

    Full Text Available The main objective of this study, is to obtain an effective particle and grain size reduction of a nanostructured iron powder by mechanical milling under different milling media. One of the main challenges in this study is to work with this material of great ductility.The variables of the study to be optimized have been the following: speed of rotation, powder to ball ratio (PBR and the percentage of control agent to induce an effective powder fracturing in front of cold welding. The powder has been characterized by a Laser Diffraction Particle Size Analyser, scanning electron microscopy (SEM and transmission electron microscopy (TEM and, X-ray diffraction.Through the comparative study, it is found that operating under dry milling conditions: there is a more effective particle size reduction of 43 % and grain size reduction of 62 %. In wet conditions has been reduced the amount of oxide, as well as to obtain a more homogenous distribution of the resulting powder. The results under cryogenic media is presented as promising.

    El principal objetivo de este estudio, es obtener una efectiva reducción del tamaño de partícula y de grano de un polvo de hierro nanoestructurado mediante la molturación mecánica en diferentes medios de molienda. La principal dificultad radica en la gran ductilidad del material. Las variables a estudiar en el proceso han sido la velocidad de rotación, la relación polvo/bolas y el porcentaje de agente de control añadido. El polvo se ha estudiado por difracción laser para caracterizar la distribución de tamaños de partículas, microscopía electrónica de barrido (SEM, microscopía electrónica de transmisión (TEM y difracción de Rayos X. Del estudio comparativo se destaca: la molienda en seco ha dado lugar a una reducción más efectiva tanto del tamaño de partícula (43% como del tamaño de grano (62%, mientras que en condiciones húmedas se ha conseguido disminuir la cantidad de óxido, así como obtener

  20. Anemia por deficiencia de hierro en mujeres mexicanas en edad reproductiva: historia de un problema no resuelto Iron deficiency anemia among Mexican women on reproductive age: history of an unresolved problem

    Directory of Open Access Journals (Sweden)

    Esther Casanueva

    2006-04-01

    Full Text Available OBJETIVO: Describir la prevalencia informada de anemia por deficiencia de hierro en mujeres mexicanas en edad reproductiva en los últimos 66 años y analizar la eficacia de las intervenciones informadas para su prevención y manejo. MATERIAL Y MÉTODOS: Revisión de estudios epidemiológicos observacionales, clínicos y programas gubernamentales de intervención, publicados entre 1939 y 2005 con información original. Se consultaron las bases de datos de la Biblioteca Nacional de Medicina de Estados Unidos, Artemisa e índices de revistas mexicanas. La calidad de los ensayos clínicos se evaluó con base en la escala Jadad. Las tendencias de la prevalencia de anemia se analizaron con una regresión lineal ponderada por el tamaño muestral. RESULTADOS: Se incluyeron 46 trabajos de investigación; nueve correspondieron a ensayos clínicos y cuatro a programas operativos; 17 informaron la prevalencia de anemia en no embarazadas y 23 en gestantes. En el primer grupo, la prevalencia ponderada de anemia ha descendido de 39.6 a 15.5%, en tanto que en las gestantes ha disminuido 10 puntos porcentuales, hasta 25%. De los estudios clínicos, 55% se consideraron con un nivel de evidencia adecuado. CONCLUSIONES: La anemia en mujeres en edad reproductiva, y particularmente en las embarazadas, aún constituye un problema de salud pública. De seguir con los esquemas actuales, se requerirían cerca de 57 años para erradicar la anemia entre las no gestantes y 121 para las gestantes. Es necesario evaluar las estrategias de intervención y hacer estudios consistentes que permitan tomar las medidas adecuadas para controlarla.OBJECTIVE: To describe the prevalence of iron deficiency anemia in the past 66 years among Mexican women on reproductive age, and to analyze the efficacy of interventions implemented for its prevention and control. MATERIAL AND METHODS: Observational and clinical epidemiological studies as well as federal intervention programs published

  1. Costo-beneficio de un programa preventivo y terapéutico para reducir la deficiencia de hierro en Argentina Cost-benefit of a prevention and treatment program to reduce iron deficiency in Argentina

    Directory of Open Access Journals (Sweden)

    Ignacio Drake

    2009-01-01

    Full Text Available OBJETIVOS: Estimar los costos directos e indirectos de la deficiencia de hierro (DH y la anemia ferropénica (AF en Argentina y compararlos con los costos de un programa específico para su prevención y tratamiento. MÉTODOS: Análisis de escenario previo (ex ante de la relación costo-beneficio de un programa de prevención y tratamiento de la AF dirigido a todos los niños y las embarazadas pobres y sin cobertura social de Argentina. Las consecuencias económicas de la DH y la AF se estimaron a partir de los costos directos - gastos vinculados a la atención de un parto prematuro - e indirectos - pérdidas en la productividad futura de los niños por su peor desarrollo cognitivo debido a la DH y la menor productividad de los adultos por la AF - mediante la metodología específica desarrollada por The Micronutrient Initiative. Las intervenciones se definieron según las Guías de Práctica Clínica vigentes en Argentina y los costos de los componentes se tomaron de los precios de las licitaciones del Ministerio de Salud de la Nación. RESULTADOS: Cada US$ 1,00 invertido en un programa de prevención y tratamiento de la DH y la AF, con una cobertura de 90% de la población de lactantes y embarazadas pobres sin seguro explícito de salud, representaría un ahorro de US$ 33,40 por la prevención de las pérdidas económicas debidas a estas enfermedades. CONCLUSIÓN: Las intervenciones para enfrentar la DH no solo mejoran significativamente el estado de salud de la población, sino que representan un ahorro considerable de recursos.OBJECTIVES: To estimate the direct and indirect cost of iron deficiency (ID and iron-deficiency anemia (IDA in Argentina and compare it with the cost of a prevention and treatment program. METHODS: Analysis of a prior scenario to gage the relative cost-benefit of an IDA prevention and treatment program for all low-income children and expectant mothers without social coverage/benefits in Argentina. The economic

  2. Influence of Water Deficit on Iron and Zinc Uptake by Matricaria chamomilla L. Influencia del Deficit Hídrico en la Absorción de Hierro y Zinc por Matricaria chamomilla L.

    Directory of Open Access Journals (Sweden)

    Alireza Pirzad

    2012-06-01

    Full Text Available Iron and zinc deficiency are a yield-limiting factor with major implications for field crop production in many agricultural regions of the world; this production is essential source of Fe and Zn in human and animal diets. Two experiments were conducted under greenhouse conditions to evaluate Fe and Zn uptake by German chamomile (Matricaria chamomilla L. grown under several drought conditions. Treatments were arranged in four irrigation regimes (95%, 80%, 65%, and 50% field capacity and six irrigation disruptions (stem formation, flower onset, full bloom, first harvest, second harvest, and control without disruption based on a randomized complete block design with five and four replicates in experiments 1 and 2, respectively. In Experiment 1, the irrigation regimes had no significant effect on Fe and Zn uptake by German chamomile, which reached total means of Fe (39.68 mg kg4 and Zn (29.15 mg kg4. In Experiment 2, the highest amount of Fe (39.0 mg kg4 was obtained from irrigation disruption at first harvest; this is similar to the results of irrigation disruption at flower onset and full bloom. However, irrigation disruption in stem formation (21.3 mg kg4, second harvest (12.95 mg kg4, and the control (7.79 mg kg4 had a decreasing trend of Fe uptake. The maximum value of Zn (40.0 mg kg4 occurred at irrigation disruption at the full bloom stage, which was also similar to irrigation disruption at flower onset and stem formation. However, later irrigation disruptions at the first and second harvest stages caused lower amounts of Zn uptake by chamomile. Therefore, the lowest Zn values were obtained from irrigation disruption at second harvest (5.0 mg kg4 and the control (5.5 mg kg4. Regressions between both Fe or Zn uptake and irrigation showed a binomial function.La deficiencia de hierro y zinc es un factor limitante de la producción con grandes implicaciones para producción de cultivo en terreno en muchas regiones agrícolas del mundo como

  3. Recovery of iron after Fenton-like secondary treatment of olive mill wastewater by nano-filtration and low-pressure reverse osmosis membranes; Recuperación de hierro tras tratamiento secundario tipo Fenton de agua residual de la industria oleícola por membranas de nanofiltración y ósmosis inversa de baja presión

    Energy Technology Data Exchange (ETDEWEB)

    Ochando-Pulido, J.M.; Victor-Ortega, M.D.; Martinez-Ferez, A.

    2016-07-01

    In this work, the performances of novel nano-filtration (NF) and low-pressure reverse osmosis (RO) polymeric membranes were examined with the aim of recovering the iron used as catalyst in former secondary treatment based on the Fenton-like advanced oxidation of olive mill wastewater (OMW). Results highlight that both membranes exhibit a good performance towards the rejection of iron (99.1% for the NF membrane vs. 100% for the low-pressure RO membrane) in the secondary-treated OMW effluent, thus permitting the recovery of iron in the concentrate stream in order to recycle it back into the oxidation reactor to reduce catalyst consumption. Finally, the permeate streams could be re-used for irrigation. Major productivity was observed by the selected NF membrane, about 47.4 L/hm2 upon 9 bar, whereas 30.9 L/hm2 could be yielded with the RO membrane under an operating pressure of 8 bar. Moreover, a sensibly lower fouling index was measured on the NF membrane (0.0072 in contrast with 0.065), which ensures major steady-state performance on this membrane and a longer service lifetime. This also results in lower required membrane area and membrane plant over dimension (4 modules in case of RO operation whereas only 2 modules for NF). [Spanish] En este trabajo, se examinó el rendimiento de membranas modernas de nanofiltración (NF) y ósmosis inversa (OI) poliméricas con el objetivo de recuperar el hierro utilizado como catalizador en un tratamiento secundario previo de agua residual oleícola (OMW) basado en oxidación avanzada tipo Fenton. Los resultados ponen de relieven que ambas membranas exhiben buen rendimiento en cuanto al rechazo de hierro (99.1 % para la membrana de NF vs. 100 % para la membrana de OI de bajas presiones) en el efluente oleícola tras tratamiento secundario, permitiendo en consecuencia la recuperación de hierro en la corriente de concentrado para su recirculación de nuevo al reactor de oxidación para reducir el consumo de catalizador. Finalmente

  4. Small-Angle Scattering of Neutrons by Iron and Nickel Close to the Curie Point; Diffusion aux petits angles des neutrons par le fer et le nickel au voisinage du point de curie; Rasseyanie nejtronov pod malymi uglami zhelezom i nikelem, blizkikh k tochke kyuri; Dispersion de neutrones en angulos pequenos por el hierro y el niquel cerca del punto de curie

    Energy Technology Data Exchange (ETDEWEB)

    Jacrot, B.; Konstantinovic, J.; Parette, G.; Cribier, D. [Centre d' etudes Nucleaires de Saclay (France)

    1963-01-15

    Recent studies on critical scattering by iron have thrown fresh light on the results obtained previously and shown that: (1) At the Curie point, scattering is inelastic. The Lorentzian form of the lines and their angular dependence establish the existence of a scattering process having the diffusion coefficient 2m {Omega}/n = 7. (2) At the Curie point, the coefficient K{sub 1}{sup 2} is less than 5 x 10{sup -5} A{sup -2}. Iron and nickel have very different angular distribution. Small-angle scattering below T{sub c} has also been studied. (author) [French] De nouveaux travaux sur la diffusion critique par le fer ont permis de completer les resultats obtenus anterieurement. Ils etablissent les faits suivants: 1. Au point de Curie la diffusion est inelastique. La forme lorentzienne des raies et leur dependance angulaire etablissent l'existence d*un processus de diffusion avec un coefficient de diffusion 2m{Omega}/n = 7. 2. Au point de Curie le coefficient K{sub 1}{sup 2} est inferieur a 5 x 10{sup -5} A{sup -2}. La distribution angulaire est tres differente dans le cas du fer et du nickel. On a egalement etudie la diffusion aux petits angles en dessous de T{sub c}. (author) [Spanish] Nuevos trabajos sobre la dispersion critica por el hierro han permitido completar los resultados obtenidos anteriormente. Dichos trabajos prueban los hechos siguientes: 1) La dispersion es inelastica en el punto de Curie. La forma lorentziana de las rayas y su dependencia angular demuestran la existencia de un proceso de dispersion con un coeficiente de dispersion igual a 2m {Omega}/n = 7. 2) En el punto de Curie, el coeficiente K{sub 1}{sup 2} es inferior a 5 x 10{sup -5} A{sup -2}. La distribucion angular es muy diferente en el caso del hierro y del ni quel. Se ha estudiado tambien la dispersion en pequenos angulos por debajo de T{sub c}. (author)

  5. Smoky indoor cooking fires are associated with elevated hemoglobin concentration in iron-deficient women Asocian el fuego con humo para cocinar dentro de la vivienda con concentraciones elevadas de hemoglobina en mujeres con deficiencia de hierro

    Directory of Open Access Journals (Sweden)

    Lynnette M. Neufeld

    2004-02-01

    álisis con una sola variable o con varias. Durante el análisis post hoc habitual para determinar si algún subgrupo particular presentaba elevación de la concentración de hemoglobina, se encontró que el empleo de fuego con humo para cocinar estaba asociado en grado significativo con la elevación de la concentración de hemoglobina en 5,2 g/L entre las mujeres con concentraciones bajas de ferritina (P < 0,10. CONCLUSIONES: La elevación de la concentración de hemoglobina debida a la exposición al aire doméstico contaminado por el empleo de combustible bioorgánico en fogones de cocina que producen humo podría tener implicaciones importantes para el diagnóstico de la anemia. Sin embargo, debido a la naturaleza observacional de este estudio, se requieren nuevas investigaciones donde se usen métodos más rigurosos para medir la exposición al monóxido de carbono y se realicen más mediciones de la cantidad de hierro en el organismo para confirmar la relación entre esta, la exposición al humo procedente de la combustión de materiales bioorgánicos para cocinar dentro de la vivienda y la concentración de hemoglobina en mujeres que viven a altitudes moderadamente altas sobre el nivel del mar. Estudios adicionales en este sentido podrían contribuir a que se ajusten los puntos de corte empleados para el diagnóstico de la anemia, si se justificara, y podrían ayudar a aclarar el posible efecto negativo de la exposición al humo producido por la combustión de materiales bioorgánicos dentro de las viviendas.

  6. Desenvolvimento de um sistema de aquecimento solar compacto utilizando termossifões bifásicos

    OpenAIRE

    Abreu, Samuel Luna de

    2003-01-01

    Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia Mecânica. O presente trabalho apresenta o desenvolvimento de um sistema de aquecimento solar compacto, que utiliza tubos de calor para transportar o calor absorvido na placa coletora para o reservatório térmico. A configuração proposta difere das concepções existentes de sistemas com tubos de calor porque o condensador é brasado à parede do reservatório térmico em vez de s...

  7. 40 CFR Appendix Ix to Part 266 - Methods Manual for Compliance With the BIF Regulations

    Science.gov (United States)

    2010-07-01

    ... the sample extraction and transport hardware, the analyzer(s), and the data recording/processing... generated without burning or processing hazardous waste (normal residue). Concentrations of toxic... 1640 1480 1340 1220 Thallium Tl 900 800 700 620 540 1 Interpolation of thermal input is not allowed. If...

  8. La otra "jaula de hierro": del fatalismo de la exclusion escolar a la recuperación del sentido de lo educativo. Una mirada desde la sociología The other "iron cage": from school exclusion fatalism to rescuing the meaning of education. A sociological perspective

    Directory of Open Access Journals (Sweden)

    Adriana Marrero

    2012-04-01

    Full Text Available El propósito de este trabajo es poner de relieve dos de las visiones más usuales sobre la institución escolar - como un mecanismo irresistible de reproducción social y como un lugar que carece de sentido para los jóvenes - y discutir, a partir de ellos, el lugar de la educación en esta etapa de la modernidad. Para ello, se revisa la tesis clásica de la jaula de hierro weberiana, la teoría de la estructuración de Giddens y el lugar de los proyectos humanos en Archer, y a partir de allí se concluye, con Charlot y Young sobre los modos como recuperar el sentido y el propósito emancipador de la educación en las sociedades contemporáneas. Desde el punto de vista empírico, se parte de la descripción de dos objetos culturales (un cortometraje y un artículo periodístico que sirven de ejemplificación de algunos de los aspectos analizados.The purpose of this article is to highlight two of the most common perspectives on education as an institution - an irresistible mechanism for social reproduction and as a meaningless place for youngsters - and from those ideas to discuss the role of education at the present stage of modernity. To do so, it will be reviewed the classic Weberian theory of the iron cage, Giddens' structuration theory, and the role of human projects in Archer's perspective. The article then concludes with the theories of Young and Charlot about the ways of recovering the meaning and emancipatory purpose of education in contemporary societies. From the empirical perspective, a description of two cultural objects (a short film and an Op-Ed is taken to illustrate some of the aspects analyzed.

  9. INFESTACIÓN E INCIDENCIA DE BROCA, ROYA Y MANCHA DE HIERRO EN CULTIVO DE CAFÉ DEL DEPARTAMENTO DEL CAUCA ESTUDO DE INFESTAÇÃO E INCIDÊNCIA DA BROCA, A FERRUGEM E A CERCOSPOREOSE O CULTIVO DO CAFÉ NO DEPARTAMENTO DO CAUCA INFESTATION AND INCIDENCE STUDY OF THE COFFEE BORER, COFFEE RUST AND IRON SPOT DISEASE ON THE COFFEE CROP IN CAUCA DEPARTMENT

    Directory of Open Access Journals (Sweden)

    CONSUELO MONTES R.

    2012-06-01

    Full Text Available El estudio de incidencia e infestación de plagas limitantes para café como Roya (Hemileia vastatrix, Broca (Hypothenemus hampei, y Mancha de hierro (Cercospora coffeicola, se desarrolló entre marzo de 2006 y Diciembre de 2007 en cuatro municipios con ocho predios sensores. Se realizaron muestreos mensuales para incidencia e infestación de cada plaga. Se siguió la metodología propuesta por CENICAFÉ, 30 árboles/ha para evaluar infestación de Broca e incidencia de la Mancha de hierro y 10 para incidencia de Roya. Se registro temperatura, precipitación, humedad relativa y brillo solar para relacionar el comportamiento de las plagas con el clima. La incidencia e infestación superaron significativamente el umbral de daño económico (5% para cada plaga. El promedio de incidencia fue de 14,7% para Roya y 4,8% para Mancha de hierro, el de infestación para Broca fue de 4,7%. La temperatura y precipitación presentaron gran relación con la dinámica epidemiológica de las plagas. Altas temperaturas están relacionadas con alta incidencia e infestación de Roya y Broca, principalmente entre junio y septiembre, contrariamente a la Mancha de hierro que estuvo relacionada con alta precipitación, principalmente entre marzo y mayo. Estos resultados alertan acerca de la presencia de estas plagas en los cultivos de la región.No departamento do Cauca foi realizado um estudo epidemiologico de três pragas limitantes na produção de café (Coffea arabica: a ferrugem produzida pelo fungo Hemileia vastatrix, a Broca do café produzida pelo inseto Hypothenemus hampei, e a cercosporiose produzida pelo fungo Cercospora coffeicola. O estudo foi feito nos anos 2006 e 2007 em quatro municipios onde foram escolhidos 8 fazendas nas que foram realizadas amostragens para obter a percentagem de apresentação das doenças. As amostragens foram feitas segundo a metodología proposta pelo CENICAFE. Trinta arbores por hectare foram avaliados para determinar a precen

  10. Anemia em gestantes brasileiras antes e após a fortificação das farinhas com ferro Anemia en gestantes brasileñas antes y después de la fortificación de harinas con hierro Anemia in Brazilian pregnant women before and after flour fortification with iron

    Directory of Open Access Journals (Sweden)

    Elizabeth Fujimori

    2011-12-01

    Full Text Available OBJETIVO: Comparar prevalência de anemia e valores de hemoglobina (Hb em gestantes brasileiras, antes e após a fortificação das farinhas com ferro. MÉTODOS: Estudo de avaliação de painéis repetidos, desenvolvido em serviços públicos de saúde de municípios das cinco regiões brasileiras. Dados retrospectivos foram obtidos de 12.119 prontuários de gestantes distribuídas em dois grupos: antes da fortificação, com parto anterior a junho de 2004, e após a fortificação, com última menstruação após junho de 2005. Anemia foi definida como Hb OBJETIVO: Comparar prevalencia de anemia y valores de hemoglobina (Hb en gestantes brasileñas, antes y después de la fortificación de las harinas con hierro. MÉTODOS: Estudio de evaluación de paneles repetidos, desarrollado en servicios públicos de salud de municipios de las cinco regiones brasileñas. Datos retrospectivos se obtuvieron de 12.119 prontuarios de gestantes distribuidas en dos grupos: antes de la fortificación, con parto anterior a junio de 2004, y posterior a la fortificación, con última menstruación después de junio 2005. Anemia fue definida como HbOBJECTIVE: To compare prevalence of anemia and hemoglobin (Hb levels in Brazilian pregnant women before and after flour fortification with iron. METHODS: A repeated cross-sectional panel study of public health care centers of municipalities in the five Brazilian regions was conducted. Retrospective data were obtained from 12,119 medical records of pregnant women distributed in two groups: before fortification (delivery prior to June 2004 and after fortification (date of last period after June 2005. Anemia was defined as Hb<11.0 g/dl. Hb levels according to gestational age were assessed using two references from the literature. Statistical analysis was carried out using chi-squared tests, Student's t tests, and logistic regression, with a significance level of 5%. RESULTS: In the total sample, prevalence of anemia fell from

  11. Influence of Irrigation Rate and Soil Type on the Vertical Migration of Iron and Manganese in the Soils of South-East Spain; Influencia de la Cantidad de Riego y Tipo de Suelo sobre la Emigracion Vertical de Hierro y Manganeso en Suelos del Sureste Espanol

    Energy Technology Data Exchange (ETDEWEB)

    Costa, F.; Carpena, O. [Instituto Nacional de Edafologia y Agrobiologia, Centro de Edafologia y Biologia Aplicada del Segura, Murcia (Spain); Esparraguera, I.; Ortin, N.; Del Val, M.; La Cruz, F. de; Cellini, R. F. [Junta de Energia Nuclear, Madrid (Spain)

    1967-11-15

    The citrus plantations in south-east Spain, situated largely on calcareous soils which are submitted to intensive cultivation, are investigating nutritional changes caused mainly by deficiencies of trace elements, especially iron and manganese, which result in a lower yield and premature exhaustion of the trees. The paper deals with a radioactive tracer study of the behaviour of these ions in soils and with the factors influencing their migration to the root zone; the object of the work is to develop a rational and economic fertilization policy. The work has been based on two types of soil, representing extreme situations encountered in practice; one soil is calcareous and the other non-calcareous. A set of columnsiwas assembled, each column having a length of 1 m and a cross-section of 32 cm{sup 2} ; solutions of {sup 59}Fe and {sup 54}Mn were added to these columns both in sulphate and chelate form. A definite amount of water, proportional to the requirements .of citrus plantations, was intermittently passed through these columns. Soil samples were taken periodically and the total activity and the activity of the assimilable and non-assimilable fractions of the elements being studied were measured. At the same time an apparatus involving a collimated scintillation detector was developed to follow the vertical migration of these ions in soils; the water drained from the columns after each irrigation was analysed radiochemically for the same purpose. (author) [Spanish] Las plantaciones citrfcolas del sureste espanol, radicadas en gran parte sobre suelos calizos y sometidos a cultivos intensivos, experimentan con el tiempo alteraciones de orden nutritivo debido principalmente a deficiencias de oligoelementos, especialmente hierro y manganeso, que se traduce en una menor produccion y en un agotamiento prematuro de los arboles. En la presente comunicacion se estudia, mediante trazadores radiactivos, el comportamiento de estos iones en los suelos, asi como los factores

  12. Riotinto Iron Mining (Huelva); Mineria de hierro en Riotinto (Huelva)

    Energy Technology Data Exchange (ETDEWEB)

    Delgado Moninguez, A.; Moreno Bolanos, A.; Perez Macias, J. A.; Gemio del Rio, G.; Regalado Ortega, M. C.

    2011-07-01

    This paper deals with the mining of reworked gossan at Riotinto (Huelva, southwest Spain). The rock in question is a conglomerate formed by the erosion of gossan and its subsequent deposition in areas at some distance from its origin. In Roman times this mineral was used as construction material as well as for architectural decoration and possibly as an ore for making mining tools. This work focuses upon the exploitation of this mineral as an iron ore mined from the site known as Mesa Pinos or Alto de la Mesa by the Rio Tinto Company Ltd. between the last quarter of the 19th century and the first part of the 20th century. (Author) 42 refs.

  13. Use of radioisotopes in studying the penetration of sulphur into iron during hydrogen cathode charging; Application des radioelements a l'etude de la penetration du soufre dans le fer lors du chargement en hydrogene cathodique; Ispol'zovanie radioehlementov dlya izucheniya proniknoveniya sery v zhelezo, kogda ona zaryazhaetsya katodnym vodorodom; Aplicacion de los radioelementos al estudio de la penetracion del azufre en el hierro durante la carga con hidrogeno catodico

    Energy Technology Data Exchange (ETDEWEB)

    Besnard, S; Talbot, J [Centre National de la Recherche Scientifique, Vitry (France)

    1962-01-15

    soufre aux joints des grains. Ce resultat, qui ne pouvait etre obtenu qu'avec l'aide des radiotraceurs, a des consequences importantes notamment dans l'industrie des petroles. Une etude analogue a ete faite en utilisant le radioisotope 32 du phosphore. (author) [Spanish] Determinados elementos, como por ejemplo el arsenico, se emplean corrientemente en el laboratorio para fomentar la penetracion del hidrogeno en el hierro. Por otra parte, se ha comprobado en la industria que la presencia de acido sulfhidrico intensifica la corrosion de los aceros por el hidrogeno. Cabia preguntarse si estas sustancias, que hasta ahora se consideraban como catalizadores, solo fomentan la absorcion del hidrogeno, o si ejercen una influencia directa sobre el metal. Los autores han estudiado este fenomeno en su laboratorio con ayuda de hierro electrolitico puro. Han efectuado la sobresaturacion con hidrogeno por carga catodica. Como sustancia de adicion emplearon sulfuro de sodio marcado con azufre-35. Lograron demostrar que en media hora a la temperatura de -15 Degree-Sign C, el azufre penetra en el hierro hasta una profundidad de unas 120 {mu}m. Han podido comprobar ademas que el azufre se localiza preferentemente en los limites intergranulares. Este resultado, que solo pudo obtenerse gracias a los indicadores radiactivos, tiene importantes consecuencias, en especial para la industria del petroleo. Los autores han realizado un estudio analogo utilizando el radioisotopo 32 del fosforo. (author) [Russian] Nekotorye ehlementy, kak naprimer mysh'yak, obychno ispol'zovalis' v laboratorii dlya oblegcheniya proniknoveniya vodoroda v zhelezo. V promyshlennosti bylo ustanovleno, chto korroziya stalej, vyzvannaya prisutstviem vodoroda, usilivaetsya pri nalichii sernistogo vodoroda. Voznikal vopros, dopuskali li ehti veshchestva, rassmatrivaemye do sikh por v kachestve katalizatorov, tol'ko samuyu bol'shuyu absorbtsiyu ili okazyvali neposredstvennoe vozdejstvie na metall. Izuchenie ehtogo yavleniya

  14. La tiroiditis bifásica: un patrón fisiopatológico en las tiroiditis

    OpenAIRE

    Marsiglia, Italo

    2008-01-01

    La disfunción tiroidea es una observación común en el curso evolutivo de las tiroiditis. En las fases avanzadas de la tiroiditis crónica autoinmune es muy frecuente el hallazgo de hipotiroidismo clínico o subclínico, como consecuencia del reemplazo glandular por la fibrosis y atrofia resultantes. El hipotiroidismo permanente también es una secuela común en la tiroiditis silente y poco frecuente en la tiroiditis subaguda. Por otra parte, se conoce como “tiroiditis destructiva”, al proceso infl...

  15. Efetividade superior do esquema diário de suplementação de ferro em lactentes Efectividad superior del esquema diario de suplementación de hierro en lactantes Greater effectiveness of daily iron supplementation scheme in infants

    Directory of Open Access Journals (Sweden)

    Catarina Machado Azeredo

    2010-04-01

    brasileiro precisa ser reavaliada para aumentar sua efetividade na prevenção de anemia em crianças atendidas em serviços públicos de saúde.OBJETIVO: Evaluar la efectividad de esquemas, diario y semanal, de suplementación profiláctica de hierro medicamentoso en la prevención de anemia ferropriva en lactantes no anémicos. MÉTODOS: Estudio poblacional, prospectivo, de abordaje cuantitativo con intervención profiláctica, realizado en el municipio de Vinosa, Sureste de Brasil, en 2007/8. Fueron seleccionados 103 niños no anémicos, entre seis y 18 meses de edad, correspondiendo a 20,2% de los niños catastrados y atendidos por los Equipos de Salud de la Familia. Los niños fueron divididos en dos grupos de suplementación: dosificación diaria recomendada por la Sociedad Brasilera de Pediatría (grupo 1, n=34 y dosificación semanal establecida por el Ministerio de la Salud (grupo 2, n=69. Las evaluaciones ocurrieron en el inicio del estudio y posterior a seis meses, siendo realizadas dosificación de hemoglobina (b-homoglobinómetro portátil, evaluación antropométrica y dietética, y aplicación de cuestionario socioeconómico. Los indicadores de impacto utilizados fueron la prevalencia de anemia, variación de hemoglobina, adhesión y efectos adversos a los suplementos. RESULTADOS: Los grupos se mostraron homogéneos con relación a las variables socioeconómicas, biológicas y de salud anteriores a la intervención. Posterior a seis meses de suplementación, se observaron mayores promedios de hemoglobina en el grupo 1 con relación al grupo 2, (11,66; DP=1,25 e 10,95; DP=1,41, respectivamente, p=0,015; así como menores prevalencias de anemia (20,6% y 43,5%, respectivamente, p=0,04. Sólo el tiempo de suplementación influyó en la anemia grave (p=0,009. No fueron encontradas diferencias estadísticamente significativas para las variables adhesión al suplemento y efectos adversos. CONCLUSIONES: La dosificación diaria recomendada por la Sociedad Brasilera de

  16. Os{sup 187}-isotope abundances in terrestrial and meteoritic osmium and an attempt to determine Re/Os-ages of iron meteorites; Anomalies dans l'abondance isotopique de l'osmium-187 dans l'osmium terrestre et meteoritique - Essai de determination de l'age des meteorites de fer au moyen du rapport Re/Os; Anomalii v rasprostranennosti izotopa osmiya-187 v zemnom i meteoritnom osmie i popytka opredeleniya vozrastov reniya/osmiya v zheleznykh meteoritakh; Anomalias en la abundancia isotopica del {sup 187}Os en el osmio terrestre y meteoritico. Ensayo para determinar la edad de los meteoritos de hierro por medio de la razon Re Os

    Energy Technology Data Exchange (ETDEWEB)

    Herr, W; Hoffmeister, W; Langhoff, J [Max-Planck-Institut fuer Chemie (Otto-Hahn-Institut) Mainz, Federal Republic of Germany (Germany); Geiss, J; Hirt, B; Houtermans, F G [Physikalisches Institut der Universitaet Bern (Switzerland)

    1962-01-15

    semblent etre de l'ordre de 3,7 a 5,6 {center_dot} 10{sup 9} ans. (author) [Spanish] Los autores han investigado por espectrometria de masas la composicion isotopica de gran numero de muestras de osmio procedentes de minerales terrestres de platino y de meteorites de hierro. Las razones isotopicas {sup 187}Os : {sup 186}Os observadas en los minerales de Os/Ir y en las muestras de Os, extraidas cuantitativamente de meteoritos de hierro, varian entre 0,88 y 1,41. Estas variaciones pueden explicarse por la formacion de Os radiogenico a consecuencia de la desintegracion del {sup 187}Re, que es el emisor natural {beta} que posee la energia {beta} mas baja conocida. Los analisis por activacion neutronica demuestran que en los meteoritos de hierro se suelen encontrar vestigios do Re y Os. Como la determinacion de la edad de estos cuerpos con ayuda de los metodos clasicos tropieza con enormes dificultades, los autores han estudiado la posibilidad de aplicar un metodo basado en la evaluacion de la razon Re/Os. Despues de haber deducido experimentalmente una razon basica {sup 187}Os : {sup 186}Os, los autores examinan la cuestion de las edades minimas. Estas varian sensiblemente y estan al parecer comprendidas entre 3,7 y 5,6 x 10{sup 9} anos. (author) [Russian] Pri pomoshchi massovoj spektrometrii byl izuchen izotopnyj sostav bol'shogo chisla prob osmiya zemnykh platinovykh rud i zheleznykh meteoritov. Poluchennoe sootnoshenie mezhdu izotopami osmiya-187 i osmiya-186 v rudakh osmiya i zheleza i v probakh osmiya, kolichestvenno, izvlechennykh iz zheleznykh meteoritov, izmenyaetsya v predelakh ot 0,88 do 1,41. EHti izmeneniya mogut byt' ob{sup y}asneny obrazovaniem radiogennogo osmiya vsled za raspadom reniya-187, yavlya- yushchegosya prirodnym beta-izluchatelem s naibolee nizkoj izvestnoj beta-ehnergiej. Aktiva- tsionnyj analiz pri pomoshchi nejtronov dokazyvaet, chto renij i osmij yavlyayutsya obshchimi ehlementami zheleznykh meteoritov, soderzhashchimisya v nikh v nichtozhnykh

  17. Self-diffusion in volume and at the grain-boundaries of gamma-iron of high purity (99.99%); Autodiffusion en volume et aux joints de grains du fer gamma de haute purete (99,99 %); Ob'emnaya samodiffuziya i samodiffuziya na poverkhnosti granul zheleza u vysokoj chistoty (99,99%); Autodifusion en volumen y en los limites intergranulares del hierro gamma de elevada pureza (99,99 por ciento)

    Energy Technology Data Exchange (ETDEWEB)

    Lacombe, P; Guiraldenq, P; Leymonie, C [Centre de Recherches Metallurgiques, Ecole Nationale Superieure des Mines, Paris (France)

    1962-01-15

    'ici avait ete appliquee uniquement a la diffusion en volume. En fait les auteurs montrent que l'on peut, par mesure de l'activite globale restante en fonction de la profondeur de penetration, distinguer la part de l'activite due a l'autodiffusion en volume de celle due a l'autodiffusion intergranulaire. L'interet de la methode est donc de suivre en continu sur un meme echantillon le passage de l'autodiffusion en volume a l'autodiffusion intergranulaire. Cette methode nouvelle a ete appliquee a la mesure des constantes d'autodiffusion en volume dans le fer gamma entre 1.260 Degree-Sign et 918 Degree-Sign C et celle aux joints des grains entre 1.020 Degree-Sign et 918 Degree-Sign C. (author) [Spanish] En vista de las dificultades que presenta la medicion exacta de los coeficientes de autodifusion, tanto masica como intergranular, en ciertos intervalos de temperatura en los que ambos fenomenos coexisten, los autores han vuelto a estudiar el metodo clasico de seccionamiento. Efectivamente, han comprobado que para un solido semi-infinito, la concentracion de atomos radiactivos C (x{sub n}), despues de la difusion, a la distancia x{sub n} del deposito radiactivo inicial es una funcion simple de la actividad global que queda en la muestra despues de una abrasion hasta la profundidad x{sub n}. Esta conclusion surge de la generalizacion de la formula de GRUZIN, que hasta ahora solo se habia aplicado a la difusion en volupien. Los autores han demostrado que, midiendo la actividad global que queda en funcion de la profundidad de penetracion, se puede distinguir la parte de la actividad debida a la autodifusion masica, de la actividad atribuible a la autodifusion intergranular. Por lo tanto, el interes del metodo estriba en que permite observar de modo continuo en una misma muestra la transicion de la autodifusion masica a la autodifusion intergranular. Los autores han aplicado este nuevo metodo a la medicion, en el hierro en fase gamma, de las constantes de autodifusion masica entre

  18. Purificação de bromelina dos resíduos de abacaxi (Ananas comosus L. Merril por sistemas bifásicos aquosos PEG/Sal

    Directory of Open Access Journals (Sweden)

    Diego de Freitas Coelho

    2011-01-01

    Full Text Available Due to the dimension of worldwide production of pineapple and to high amount of generated waste from its cultivation and processing, several research have been developed to recovery the enzymes presents on pineapple, such as bromelain. Bromelain is the general name given to the group of endopeptidases found in pineapple as well as all proteases derived from members of the family Bromeliaceae, which belongs to the pineapple. Because of that play important physiological roles, these enzymes offers a wide range of proven therapeutic applications. This work aims the purification of bromelain from pineapple waste through PEG/Salt aqueous two-phase systems (ATPS using (NH42SO4, CaCl2 and potassium phosphate. The results showed that in CaCl2 experiments have no ATPS formation in the range of its constituents. However, the PEG/phosphate systems and PEG/(NH42SO4 systems showed excellent results, recovering with bromelain purification factor of 7.4 and 10.7 times, respectively, and yields above 80%.

  19. Economia de átomos, engenharia molecular e catálise organometálica bifásica: conceitos moleculares para tecnologias limpas

    OpenAIRE

    Dupont,Jairton

    2000-01-01

    For economical and ecological reasons, synthetic chemists are confronted with the increasing obligation of optimizing their synthetic methods. Maximizing efficiency and minimizing costs in the production of molecules and macromolecules constitutes, therefore, one of the most exciting challenges of synthetic chemistry. The ideal synthesis should produce the desired product in 100% yield and selectivity, in a safe and environmentally acceptable process. In this highlight the concepts of atom ec...

  20. Clústeres Calcogenuro de Metales del Grupo 6 con Relevancia en Catálisis Asimétrica y Bifásica

    OpenAIRE

    Guillamón Torres, Eva

    2009-01-01

    El trabajo de investigación que se expone en esta Tesis Doctoral presenta la síntesis de una nueva familia de compuestos trinucleares de fórmula general [M3Q4X3(difosfina)3]+ (M = Mo, W; Q = S, Se; X = Cl, Br, H) y son el punto de partida para la preparación de nuevos derivados heterodimetálicos M3M'Q4 (M' = Cu, Pd y Ni). Atendiendo a la naturaleza del ligando difosfina incorporado a la unidad, estos compuestos poseen diferentes propiedades. Concretamente, se han incorporado difosfinas solu...

  1. Sistemas aquosos bifásicos: fundamentos e aplicações para partição/purificação de proteínas

    OpenAIRE

    Silva,Luis Henrique Mendes da; Loh,Watson

    2006-01-01

    By the year 2005 the world biochemical market will reach an estimated $ 100 billion and separation processes are a vital link between lab discoveries and the fulfillment of this commercialization potential. The practical application of aqueous two-phase systems (ATPS) to extraction processes has been exploited for several years for the recovery of biological products. Unfortunately, this has not resulted in an extensive presence of the technique in commercial processes. In this paper a critic...

  2. DESULFURACIÓN DE RELAVE MEDIANTE LA FLOTACIÓN DE SULFUROS DE HIERRO

    Directory of Open Access Journals (Sweden)

    Luis Valderrama Campusano

    2015-12-01

    Full Text Available En Chile la minería se desarrolla principalmente en  la concentración de cobre, molibdeno, oro y plata, mediante el proceso de flotación. Este genera grandes tonelajes de relaves que contienen diversas minerales, principalmente pirita. Dado que estos minerales se depositan en los tranques, estos pueden generar aguas ácidas; se propone como alternativa la desulfuración de los súlfuros por flotación. En una primera parte se estudió la flotabilidad de la pirita en un tubo Hallimond, utilizando como colector AP 404. Luego se realizaron pruebas de flotación a nivel de laboratorio en celda Denver D-12, utilizando pulpa de relave fresco de la etapa rougher de un circuito de flotación de cobre,  determinando el pH óptimo y dosificación de colector y espumantes. Pruebas de cinética de flotación permitieron determinar el tiempo óptimo de flotación tanto para la etapa rougher como  para la etapa scavenger. Se concluye que la flotación de los relaves sea una técnicamente factible su desulfuración,  obteniendo relaves que contienen  0,08% de pirita.

  3. Estado actual del conocimiento de la Prehistoria salmantina (hasta la Edad del Hierro

    Directory of Open Access Journals (Sweden)

    Juan MALUQUER DE MOTES

    2009-10-01

    Full Text Available La provincia de Salamanca sin alcanzar la densidad de otras provincias norteñas y levantinas principalmente, puede decirse que en cuanto a su prehistoria se refiere, ocupa un lugar privilegiado en el conjunto de provincias centro este peninsulares, por cuanto ha tenido la fortuna de poseer durante largos años su propio investigador, el Padre César Morán Las primeras excursiones por la prehistoria provincial, las efectuó sin embargo don Manuel Gómez Moreno que en breves pinceladas, hace ya más de cuarenta años, con certera visión planteó muchos problemas que en parte se mantienen aún sin resolver.

  4. Iron and manganese deposits in Uruguay; Los yacimientos de hierro y manganeso en el Uruguay

    Energy Technology Data Exchange (ETDEWEB)

    Alvarado, B

    1959-07-01

    This report is the results of the study carried out for the United Nations expert which the main object was: the study of the information available about iron and manganese formation in Uruguay, as well as the main researching deposit to determinate economical possibilities in the exportation.

  5. Economic value of Valentines iron minerals; Valor economico de los minerales de hierro de Valentines

    Energy Technology Data Exchange (ETDEWEB)

    Alvarado, B.

    1960-07-01

    This work is a investigation required by the government of Uruguay about the economic value of iron and manganese deposits in Valentines ferriferrous zone. The purpose is to study the potential commercial for the exportation.

  6. Superconductores de alta Temperatura Crítica a base de Hierro

    Directory of Open Access Journals (Sweden)

    O Rodríguez León

    2009-01-01

    Full Text Available The discovery in early 2008 of a new family of superconductors with a Tc~26K in an iron compound and fluorine doped, LaO1-xFxFeAs, has revived interest in the search for superconducting materials with high critical temperature. The discovery has led to an accelerated study of superconducting properties and many other physical properties, resulting in obtaining new compounds with critical temperatures between 26 - 55 K. In this article it is intended to summarize the main physical and chemist characteristics of this family and related compounds.

  7. Cerámicas a torno pintadas andaluzas de la segunda Edad del Hierro

    OpenAIRE

    Escacena Carrasco, José Luis

    1986-01-01

    El estudio de las vajillas cerámicas de las culturas antiguas desde el punto de vista puramente tipológico se ha revelado, a pesar de su aridez, como una de las bases fundamentales para iniciar investigaciones de otra índole referidas a los grupos humanos que las utilizaron. En este sentido, y por lo que se refiere a la Península Ibérica, todavía muchas de sus etapas pre y prohistóricas, además de otros momentos más recientes qu...

  8. Impacto del programa Mi Amigo el Hierro en el estilo de vida alimentario para prevenir la anemia

    OpenAIRE

    Chanducas Lozano, Bertha

    2009-01-01

    Objetivo: Determinar el impacto del Programa “Mi Amigo el Hierro” en el estilo de vida alimentario para prevenir la anemia en los alumnos de Nutrición Humana de la Universidad Peruana Unión, Lima 2006.Metodología: El diseño de la investigación fue pre–experimental porque se trabajó con un grupo de alumnos a quienes se les aplicó un cuestionario antes y después del programa de intervención “Mi Amigo el Hierro”.Resultados: Después de aplicar el programa “Mi Amigo el Hierro”, el 60.7% de los alu...

  9. Removal of remazol yellow with modified clays with iron; Remocion de amarillo remazol con arcillas modificadas con hierro

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Gomez T, A. P.

    2012-07-01

    Clays have the ability to absorb water and to retain in its structure both hydrophilic and hydrophobic substances, therefore, it is possible to use them in the sorption of dyes from waste water, in order to avoid affecting water bodies or storm drains when they are discharged. In this paper the montmorillonite KSF and a sodium bentonite from the Morelos State, Mexico were studied for the sorption of an azo dye used in textiles knows as remazol yellow. These clays were modified with iron, the dye sorption behaviors and their regeneration processes for their reuse were determined. It was difficult to separate the sodium bentonite after being in contact with aqueous solutions; therefore it was nor a candidate dor the removal of remazol yellow from aqueous solutions. The montmorillonite KSF was characterized before and after the iron modification, and after its regeneration by scanning electron microscopy (elemental analysis), infrared spectrometry, X-ray diffraction, and the specific areas of the materials were determined by Bet analysis. The adsorption equilibrium time and the adsorption rate for remazol yellow were determined from the fitting of the experimental results to mathematical models for the unmodified and iron modified montmorillonite KSF. The adsorption capacity was determined from the adsorption isotherms and mathematical models. The influence of the ph in the sorption processes was determined as well, and it was found that, ph values between 2 and 12 do not have any influence on the adsorption processes for iron modified montmorillonite KSF. The montmorillonite KSF and the iron modified montmorillonite KSF are adequate adsorbents for the removal of remazol yellow from aqueous solutions. Although, the sorption capacity for the unmodified montmorillonite KSF is higher (about 10%) than the capacity for the iron modified montmorillonite KSF and the stability of the last one increased. The saturated clays with remazol yellow were treated with Fenton reactive, hydrogen peroxide and distilled water to determine their regeneration behaviors. Any desorption process was not observed when the clays were treated with distilled water. The regeneration was best accomplished with Fenton reactive, the sorption increased in about 300% in comparison with the original capacity. The iron modified montmorillonite shows a better sorption behavior after regeneration than the unmodified montmorillonite KSF. (Author)

  10. Fortificaciones de la II Edad del Hierro en el Bajo Aragón : un estilo regional

    OpenAIRE

    Melguizo , Salvador; Moret , Pierre

    2006-01-01

    International audience; Se estudian en esta comunicación las fortificaciones del final de la época ibérica en dos áreas del Bajo Aragón: la desembocadura del Regallo, en Caspe, con los yacimientos de La Tallada y Palermo I, y el valle medio del Matarraña, entre Calaceite y Valdeltormo, con los yacimientos de San Antonio, Els Castellans y Torre Cremada. Se observa en ellos un patrón repetitivo, caracterizado por la presencia de tres elementos, concentrados en la zona de acceso más vulnerable: ...

  11. Obtención de pelets a partir de mineral de hierro en procesos de reducción directa

    Directory of Open Access Journals (Sweden)

    Diana Carolina Africano Higuera Álvaro Forero Pinilla

    2010-12-01

    Full Text Available Inicialmente  se  realizó  la  toma  de  muestras representativas de  finos de mineral, aglomerantes y carbones motivo  de  estudio,  para  efectuar  su caracterización.  Paralelamente,  se  puso  a  punto  el disco peletizador de los laboratorios de la Escuela de Metalurgia de la UPTC. Luego se procedió a realizar mezclas de finos de mineral, de carbón y aglomerante, con el fin de encontrar las proporciones ideales para obtener pelets de alto rendimiento, teniendo en cuentacondiciones cinéticas y termodinámicas del proceso. El diseño experimental determinó que el número de ensayos por realizar es de 48, es decir, 3 repeticiones por cada muestra. Enseguida  se  realizaron ensayos para estudiar la reducibilidad de los pelets, evaluando el  comportamiento  de  estos  con  cada  uno  de  los aglomerantes una vez se ha alcanzado la temperatura de reducción. El prerreducido obtenido se analizó por métodos químicos y microscópicos.

  12. Development and recent activity of the San Andrés landslide on El Hierro, Canary Islands, Spain

    Czech Academy of Sciences Publication Activity Database

    Klimeš, Jan; Yepes, J.; Becerril, L.; Kusák, Michal; Galindo, I.; Blahůt, Jan

    2016-01-01

    Roč. 261, MAY 15 (2016), s. 119-131 ISSN 0169-555X R&D Projects: GA MŠk LM2010008 Grant - others: National Geographic Society W244-12 Institutional support: RVO:67985891 Keywords : Deep-seated gravitational slope deformations (DSGSDs) * Landslide monitoring * Creep movements * Canary Islands Subject RIV: DE - Earth Magnetism, Geodesy, Geography Impact factor: 2.958, year: 2016

  13. Tratamiento de disoluciones que contienen cromo hexavalente mediante electrocoagulación con ánodos de hierro

    OpenAIRE

    ARROYO NÚÑEZ, MARÍA GUADALUPE

    2011-01-01

    Los residuos de cromo hexavalente y sus compuestos se originan en industrias tales como la fabricación de coches, el refino del petróleo, el tratamiento de superficies, la preparación de cromato, las industrias de fertilizantes y las industrias que emplean componentes de Cr(VI) como inhibidores de la corrosión. Los compuestos derivados del Cr(VI) son muy contaminantes, tienen un efecto altamente oxidante y facilidad para penetrar en membranas biológicas, además de ser cancerígenos para los...

  14. La Evolución de la Lanza en Occidente (Piezas de Hierro de Hallstatt al Siglo XV

    Directory of Open Access Journals (Sweden)

    Cirlot, Juan Eduardo

    1967-12-01

    Full Text Available See Abstract in Spanish.

    DETERMINAR la evolución de la lanza es difícil, incluso en el área occidental. Fijar el período a que corresponde una determinada pieza con frecuencia implica los más graves problemas, y la posibilidad de error siempre está al acecho. Naturalmente, seriar cronológicamente lanzas de fecha determinada por hallazgos arqueológicos precisos: excavaciones de ruinas, tumbas, etc., es fácil. Pero aplicar los resultados que se obtienen con esta organización supuesta ya no lo es tanto. Ello se debe esencialmente a un hecho: la falta de caracterización estilística suficiente en gran número de piezas, aunque es innegable que hay otras cuya forma «dice» con claridad a qué mundo cultural pertenecen. Complementa esa falta de caracterización la riqueza tipológica que suele darse en cada período. El canon varía con libertad e igualmente las dimensiones e incluso la técnica. Para el coleccionista de lanzas, o para el investigador que se enfrenta con piezas que no proceden de hallazgos fechados, es muy arduo, pues, saber con aproximación a qué época y lugar corresponden tales armas. Tiene a su disposición varios elementos de juicio: la comparación con las armas procedentes de hallazgos fechados, la «calidad» (textura de la pieza, es decir, su aspecto táctil, que acaba por ser inconfundible o poco menos para el que frecuenta los objetos antiguos. Finalmente, por escasa que sea la «caracterización estilística», siempre hay alguna, y ayuda a corroborar o a rectificar las hipótesis formuladas con la base de los dos principios primeros.

  15. Simulating Precambrian banded iron formation diagenesis

    DEFF Research Database (Denmark)

    Posth, Nicole R.; K??hler, Inga; D. Swanner, Elizabeth

    2013-01-01

    Post-depositional diagenetic alteration makes the accurate interpretation of key precipitation processes in ancient sediments, such as Precambrian banded iron formations (BIFs), difficult. While microorganisms are proposed as key contributors to BIF deposition, the diagenetic transformation...

  16. Efeitos da massa molar e do pH sobre o equilíbrio termodinâmico do sistema bifásico aquoso PEG/fosfatos

    Directory of Open Access Journals (Sweden)

    Juliana Ferrari Ferreira

    2009-01-01

    Full Text Available Aqueous two-phase systems have been largely used in research for separation and purification of biomolecules. These systems are obtained through the mixture of two polymers or one polymer and a salt solution. The main subject of this work was the characterization of aqueous two-phase systems from different poly (ethylene glycol with molecular weights of 1500, 4000 and 6000 and potassium phosphate salts at pH varying from 6 to 8 at standard conditions. It was observed a displacement of the binodal towards lower polymer concentrations when PEG molecular weights increased. On the other hand, the variation of pH did not promote significant alterations on the binodal. In the tie lines, it was not possible to stabilize the values of compositions influence, even when the polymers had been compared with themselves and different pHs.

  17. Use of Short-Lived Radioisotopes to Determine Impurities in Aluminium, Iron and Zirconium of Very High Purity; Dosages d'Elements par leurs Radioisotopes de Periodes Courtes Dans l'Analyse de Valuminium, du Fer et du Zirconium de Tres Hautes Puretes; ДОЗИРОВКА ЭЛЕМЕНТОВ С ПОМОЩЬЮ КОРОТКОЖИВУЩИХ РАДИОИЗОТОПОВ ПРИ АНАЛИЗЕ АЛХМИНИЯ, ЖЕЛЕЗА И ЦИРКОНИЯ ОЧЕНЬ ВЫСОКОЙ ЧИСТОТЫ; Determinacion Cuantitativa de Radioisotopos de Periodo Corto en los Analisis de Aluminio, Hierro y Circonio de Alta Pureza

    Energy Technology Data Exchange (ETDEWEB)

    Albert, Ph.; Deyris, M.; Deschamps, N.; Fournet, L. [Centre d' Etudes de Chimie Metallurgique, Vitry (France)

    1963-03-15

    } * s. Les separations prealables a l'irradiation sont necessaires pour obtenir de plus grandes sensibilites et aussi dans le cas des metaux de moins grande purete. Dans leur memoire, les auteurs montrent la contribution importante que les dosages par les radioisotopes de courtes periodes (2,4 min a 4, 6 h) apportent a la connaissance du degre de purete des echantillons. (author) [Spanish] En el laboratorio del Profesor Chaudron, en Vitry, los autores analizan sistematicamente por 'radiactivacion' metales de grado de pureza muy elevado como el aluminio, hierro, circonio y cobre purificados por el metodo de la 'zona fundida', asi como metales industriales muy puros refinados por electrolisis doble en el caso del aluminio, electrolisis simple en el del cobre, disociacion termica del yoduro en el del circonio, y purificacion del compuesto carbonilo en el del hierro. Han realizado estos analisis irradiando las muestras con neutrones, deuterones, protones y fotones y de 30 MeV a fin de determinar cuantitativamente el oxigeno, el carbono y el nitrogeno. El analisis sistematico despues de la irradiacion neutronica se limita a unos 50 elementos. En efecto, algunos isotopos tienen periodos demasiado breves, como el vanadio-52 (3,7 min), el cloro-38 (37,5 min), el yodo-128 (25 min), el aluminio-28 (2,4 min), el magnesio-27 (9,5 min) y el titanio-51 (5,8 min). Otros elementos no se pueden separar y valorar con sensibilidad suficiente para un analisis sistematico; este es principalmente el caso del silicio-28 de 2,8 h de periodo (seccion eficaz de captura muy baja y emision de radiaciones 0' puras) Sin embargo, es preciso conocer la concentracion de estos elementos en los metales citados porque, en ciertos casos, constituyen impurezas de base de los materiales industriales sometidos al tratamiento de purificacion; en otros casos suele encontrarse un contenido mas elevado en el metal purificado que en el metal de origen. Com ejemplo, los autores senalan la importancia de la

  18. Immobilization of Cr(Vi) as a contaminant from soil by iron compounds; Inmovilizacion de Cr(VI) como contaminante del suelo por compuestos de hierro

    Energy Technology Data Exchange (ETDEWEB)

    Marin A, M. de J.; Romero G, E. T. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Reyes G, L. R. [Universidad Autonoma del Estado de Hidalgo, Centro de Investigacion en Ciencias de la Tierra, Carretera Pachuca-Tulancingo Km. 4.5, Pachuca 42184, Hidalgo (Mexico)], e-mail: elizabeth.romero@inin.gob.mx

    2008-07-01

    The objective of this research was to determine the physicochemical and surface properties of Fe{sup 0} and FeS to select the appropriate radioactive material for use in the design of artificial barriers or walls and remove Cr (Vi). The physicochemical characterization was carried out of iron: Fe{sup 0} and FeS, using scanning electron microscopy of high vacuum, X-ray diffraction and thermal gravimetric analysis techniques. As for the characterization of the surface, was used to determine the surface area, point of zero charge, density of active sites and kinetics of moisture. We obtained a solution of Cr (Vi) by elution of deionized water on the pollution land of Buenavista, Guanajuato. The concentration of Cr (Vi) from a stock solution was 55.56 mg / L determined by UV-Vis spectrophotometry. Stripping or maximum immobilization of Cr (Vi) with Fe{sup 0} (material chosen by their physicochemical and surface properties) was 68.25% using Fe{sup 0}, at a concentration less than 0.1, ph equal to 3 and a contact time of 24 hours. (Author)

  19. EVALUACIÓN DEL CONTENIDO DE HIERRO EN LA GUAYABA (PSIDIUM GUAJAVA Y PIMENTÓN (CAPSICUM ANNUM L Y SU IMPACTO COMO COMPLEMENTO EN LA DIETA

    Directory of Open Access Journals (Sweden)

    Ruth Alvarez

    2017-07-01

    Full Text Available Ingerir alimentos conocidos en Venezuela como guayaba (Psidium guajava y pimentón (Capsicum annum L., pueden estimular la fijación de Fe (II; en el organismo, por lo que, evaluar su participación y sinergia en el cuerpo es de suma importancia. La evaluación estuvo basada en una metodología de diseño no experimental, de tipo campo, con nivel descriptivo. Para ello, se trataron entre 30 a 35 g de cada especie, para la guayaba en diferentes disposiciones (trozos: t, jugo: j y residuo: r, para el pimentón (t y para la mezcla de ambas especies (jugo y residuo. Después de digerir las muestras con HCl 6M a 100° C, se analizaron por espectroscopia de absorción atómica (EAA y espectroscopia de absorción molecular (UV- visible (EAM, acomplejando el Fe (II con o-fenantrolina. Los resultados obtenidos sugieren que la guayaba presenta mayor concentración de Fe en el orden r>t>j. En el pimentón la concentración de Fe resultó ser mayor en los trozos en comparación con los valores obtenidos en la guayaba (trozos y jugo y la mezcla de ambos con excepción del residuo de la guayaba y de la mezcla. Los resultados sugieren que la fruta y hortaliza estudiada pueden ser utilizadas como complemento en la dieta alimenticia del ser humano.

  20. Evolution of sensitivity to fosfomycin in bacteria isolated in 1973, 1974 and 1975 in the Servicio de Microbiologia y Epidemiologia of the 'Clinica Puerta de Hierro', Madrid.

    Science.gov (United States)

    Dámaso, D; Moreno-López, M; Martínez-Beltrán, J

    1977-01-01

    The bacteriostatic activity of fosfomycin was studied in vitro against 1,243 clinical isolations of gram-positive cocci and 4,086 isolations of gram-negative bacilli that were obtained in 1973, 1974 and in the period from January to May of 1975. MIC was determined by the agar diffusion method, quantifying it by means of the standard curve that was worked out with the strain of E. coli NCTC 10,418. A slight increase in resistance was observed in the gram-positive cocci: 64 mug/ml were inhibitory for 63% of the 249 isolations obtained in 1973, 59.1% of the 716 isolations obtained in 1974, and 57.5% of the 278 isolations from 1975. A slight loss of sensitivity was also observed in the gram-negative bacilli: the aforementioned concentration of fosfomycin inhibited 36% of the 742 isolations from 1973, 33.6% of the 2,387 isolations from 1974 and 32.6% of the 957 isolations from 1975. 933 g of this antibiotic were consumed in our hospital in 1973, 4,203 g in 1974 and 957 g in 1975. The consumption rate per patient per year was 0.15, 0.72 and 0.20 g, respectively. In conclusion, although no change was observed in the sensitivity of some bacterial strains to fosfomycin, the overall study indicates a slight decrease in the sensitivity, although it does not apparently have any relationship to the consumption of fosfomycin in our hospital.

  1. Electrodeposición de nanohilos magnéticos: aleaciones de FeNi y óxidos de hierro y de cobalto

    OpenAIRE

    Llavona Serrano, Ángel

    2013-01-01

    El principal objetivo del trabajo de esta tesis doctoral ha sido la fabricación de nanohilos con diferentes aplicaciones tecnológicas mediante electrodeposición dentro de los poros de membranas de policarbonato, el estudio de los procesos de crecimiento y el estudio de sus propiedades estructurales, magnéticas y luminiscentes.

  2. Cas pratique : État de la retenue d’El Golfo dans l’île d’El Hierro (îles Canaries

    Directory of Open Access Journals (Sweden)

    BLANCO, Manuel

    2012-08-01

    Full Text Available La pérennité des matériaux géosynthétiques garantit la mise en place d'un système de protection efficace et durable pour l'environnement. Cet article présente le comportement sur douze ans d’une géomembrane en caoutchouc synthétique installée dans la retenue d'eau d’El Golfo aux îles Canaries : des résultats encourageants qui montrent un bon état de conservation de la géomembrane face aux aléas climatiques.

  3. Hierro, oxígeno y desarrollo placentario en la génesis de la preeclampsia: Efectos de la altura en Ecuador

    OpenAIRE

    Escudero,Carlos; Calle,Andrés

    2006-01-01

    Preeclampsia is the second cause of maternal death in Ecuador. The etiology of this condition is probably a placental alteration, although the details are not well known. The development of the placenta is closely related to the availability of oxygen. A defect in the differentiation of trophoblastic cells due to a faulty sensitization to changes in oxygen pressure, could be the cause of the alteration in placental development. The role of iron and local environmental conditions of a suscepti...

  4. Caracterización estructural de vidrios con altos contenidos de óxidos de hierro obtenidos a partir de un residuo de la hidrometalurgia del zinc

    OpenAIRE

    Romero, M.; Rincón, J. María; Mûsik, S.; Kozhukharov, W.

    1997-01-01

    It has been carried out the structural characterization of high oxide content glasses obtained by melting of a goethite industrial waste from the zinc hydrometallurgy with other raw materials as dolomite and glass cullet. The structural characterization has been carried out by X-Ray Diffraction (XRD), X-Ray Diffraction by Amorphous Dispersion (RDF) and Mossbauer spectroscopy. It has been determined the interatomic distance, the oxidation state and the coordination of iron atoms in these glass...

  5. DETERMINACIÓN DE CALCIO, HIERRO Y FÓSFORO EN UN PRODUCTO FERMENTADO DE SOJA OBTENIDO POR ULTRAFILTRACIÓN

    OpenAIRE

    Ana N. Rinaldoni; Ernesto Perino; Mercedes E. Campderrós; Antonio Pérez

    2011-01-01

    El objetivo de este trabajo fue obtener un producto fermentado de soja a partir de un concentrado de leche de soja, empleando la ultrafiltración para alcanzar el contenido de sólidos totales requerido para la producción de yogur (12-14% p/p). Además, se propuso evaluar el empleo de la Fluorescencia de rayos X como técnica para cuantificar el contenido de Ca, Fe y P y su distribución final por el proceso ensayado. Las determinaciones analíticas se realizaron sobre la leche de soja, concentrado...

  6. DETERMINACIÓN DE CALCIO, HIERRO Y FÓSFORO EN UN PRODUCTO FERMENTADO DE SOJA OBTENIDO POR ULTRAFILTRACIÓN

    Directory of Open Access Journals (Sweden)

    Ana N. Rinaldoni

    2011-01-01

    Full Text Available El objetivo de este trabajo fue obtener un producto fermentado de soja a partir de un concentrado de leche de soja, empleando la ultrafiltración para alcanzar el contenido de sólidos totales requerido para la producción de yogur (12-14% p/p. Además, se propuso evaluar el empleo de la Fluorescencia de rayos X como técnica para cuantificar el contenido de Ca, Fe y P y su distribución final por el proceso ensayado. Las determinaciones analíticas se realizaron sobre la leche de soja, concentrado, permeado y producto fermentado, empleando fluorescencia de rayos X dispersiva en longitud de onda (WDXRF. Los resultados mostraron que estos elementos son concentrados por la membrana a través de asociaciones con las proteínas, conservando el aporte de minerales del producto. Además, se demostró que la herramienta analítica empleada permite una determinación directa sobre las muestras, evitando el pre-tratamiento requerido por otras técnicas convencionales.

  7. Obtaining of iron particles of nanometer size in a natural zeolite; Obtencion de particulas de hierro de tamano nanometrico en una zeolita natural

    Energy Technology Data Exchange (ETDEWEB)

    Xingu C, E. G.

    2013-07-01

    The zeolites are aluminosilicates with cavities that can act as molecular sieve. Their crystalline structure is formed by tetrahedrons that get together giving place to a three-dimensional net, in which each oxygen is shared by two silicon atoms, being this way part of the tecto silicate minerals, its external and internal areas reach the hundred square meters for gram, they are located in a natural way in a large part of earth crust and also exist in a synthetic way. In Mexico there are different locations of zeolitic material whose important component is the clinoptilolite. In this work the results of three zeolitic materials coming from San Luis Potosi are shown, the samples were milled and sieved for its initial characterization, to know its chemical composition, crystalline phases, morphology, topology and thermal behavior before and after its homo-ionization with sodium chloride, its use as support of iron particles of nanometer size. The description of the synthesis of iron particles of nanometer size is also presented, as well as the comparison with the particles of nanometer size synthesized without support after its characterization. The characterization techniques used during the experimental work were: Scanning electron microscopy, X-ray diffraction, Infrared spectroscopy, specific area by means of BET and thermogravimetry analysis. (Author)

  8. Precipitation of iron (III) using magnesium oxide in fluidized bed; Precipitacion de hierro (III) utilizando oxido de magnesio en lecho fluidizado

    Energy Technology Data Exchange (ETDEWEB)

    Esteban-Bocardo, P. A.; Ferreira-Rocha, S. D.

    2006-07-01

    A process for iron (III) removal by hydroxide precipitation from and acid synthetic inorganic effluent using magnesium oxide as an alternative precipitant agent in a fluidized bed was developed. An acid synthetic inorganic effluent containing 100 and 200 mg/l of ferric ions (pH=1.0) was continuously fed up to the acrylic column (30 cm high and 2 cm diameter) during 180 minutes. Magnesium oxide pulp (3% v/v) was injected at the beginning of the experiment in order to allow the iron hydroxides precipitation. The concentration and pH profiles agreed in their curves, while the pH profile rose,the concentration profile decreased and a high percentage of iron removal (higher to 99%) was reached. Extremely low iron concentrations have been reached, thus permitting to attend to the environmental standard of 10.0 mg/l for discharge of effluent containing ferric ions established by the law DN 10/86 of COPAM (Conselho de Politica Ambiental do Estado de Minas Gerais-Brazil). (Author)

  9. The submarine volcano eruption off El Hierro Island: Effects on the scattering migrant biota and the evolution of the pelagic communities

    KAUST Repository

    Ariza, Alejandro; Kaartvedt, Stein; Rø stad, Anders; Garijo, Juan Carlos; Arí stegui, Javier; Fraile-Nuez, Eugenio; Herná ndez-Leó n, Santiago

    2014-01-01

    , acidification, rising temperature and deposition of chemicals in shallow waters resulted in a reduction of epipelagic stocks and a disruption of diel vertical migration (nocturnal ascent) of mesopelagic organisms. Furthermore, decreased light levels at depth

  10. Direct reading spectrochemical determination of aluminium, iron and silicon in fluorite; Determinacion espectroquimica de lectura directa de aluminio, hierro y silicio en fluorita

    Energy Technology Data Exchange (ETDEWEB)

    Roca, M

    1966-07-01

    A quantitative spectrochemical method for the determination of Al, Fe and Si in fluorite has been worked out. The sample was supported in a graphite electrode with crater of 5 mm. in diameter, 2,5 mm deep, and burned by a d.c. are in a direct reading spectrometer. The excitation of samples has been studied without dilution as well as using graphite powder as diluent in the ratios 1:1, 1:4, and 1:9; the latter factor was chosen. Ag, Ca, Co, Cr, Mo and Sn were tested as internal standards. It has not been found any significant inter element effect. It is necessary to use natural fluorite as base material for the standards. (Author) 5 refs.

  11. Synthesis and characterization of iron nano particles for the arsenic removal in water; Sintesis y caracterizacion de nanoparticulas de hierro para la remocion de arsenico en agua

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez M, O. E.

    2011-07-01

    The synthesis of iron nanoparticles for the removal of metallic ions in polluted waters has been during the last years study topic for different world organizations. This work presents a synthesis method of conditioned coal with iron nanoparticles starting from the use of leaves of pineapple crown, with the purpose of using it in arsenic removal processes in aqueous phase. For the synthesis of this material, the leaves of the pineapple crown were used like supports structure of the iron nanoparticles. First, the pyrolysis appropriate temperature was determined. For the preparation of the support material, this had contact with a ferric nitrate and hexamine solution, because the preparation of the material and the coal synthesis were realized during the pyrolysis process, where the hexamine molecules and the ferric nitrate react, causing the reduction of the iron particles and their dispersion on the support material, obtaining as product a conditioned coal with iron nanoparticles. For the characterization of the materials were used techniques as: Scanning electron microscopy, Transmission electron microscopy, X-Rays Diffraction), X-Ray photoelectron spectroscopy and Moessbauer spectroscopy; moreover was determined the isoelectric point and the density of surface sites. The arsenic sorption capacity of the materials was evaluated by means of the methodology type lots where was determined the sorption kinetics and isotherms in terms of arsenic concentration and mass. (Author)

  12. Consideraciones sobre la rotura por fatiga de contacto en el hierro nodular austemplado. // Considerations on the contact fatigue failure in the austempered nodular iron.

    Directory of Open Access Journals (Sweden)

    D. Moreno Mur

    2004-09-01

    Full Text Available El presente trabajo considera como factor importante la variación de la geometría del nódulo de grafito en el cálculo delnúmero de ciclos necesarios durante la formación de un pitting en una fundición nodular austemplada. En este caso se tomóen cuenta la aparición de una energía de deformación alrededor de este y se consideró el material con propiedadeshomogéneas. Es analizada la influencia de la variación de la carga, los valores de los diámetros de contacto, el tamaño delnódulo de grafito, de la profundidad donde aparece el nódulo en la geometría del nódulo, por ser estos factores importantesen la iniciación y propagación de grietas por fatiga de contacto. Se trabajó con las profundidades donde aparecen lasmáximas tensiones tangenciales, las cuales se obtuvieron de las expresiones de Hertz, con valores de carga dentro del límiteelástico. Luego se modela por elementos finitos el mecanismo de fractura, en el sistema ALGOR 12.06, y se realiza unaregresión múltiple en el sistema STATGRAPHICS, obteniendo modelos con buenos coeficientes de regresión y niveles deconfianza.Palabras claves: Fatiga de contacto, factura, grietas, nódulo grafito, FEM._________________________________________________________________________Abstract.The present paper deal with the failure of contact fatigue in the autempered ductil iron considering the graphite nodulesvariation as an important factor in th calculation of the number of cycles nedded for pitting, starting from theoreticalconsiderations, developing a methodology for the calculation. The influence of load variation is analyzed, the values of thecontact diameters, the size of graphite nodules, the depth where the nodule appears in the geometry of the nodule, areimportant factors in the initiation and propagation of contact fatigue cracks. It is considered the depths in wich the maximstangential tensions appear, which were obtained by Hertz expressions. An analysis by the method of finite elements with aproffesional software was carried out obtaining the best mesh for a convergence analysis and a regression analysis withSTATGRAPHICS, in order to obtain numeric models that related the signal parameters.Key words: Contac Fatigue, Fracture, Cracks, Graphite Nodule, Finite Elements.

  13. Removal of yellow 5 by a zeolitic material conditioned with iron; Remocion de amarillo 5 por un material zeolitico acondicionado con hierro

    Energy Technology Data Exchange (ETDEWEB)

    Alcantara C, A.

    2010-07-01

    The waste waters are at the present time a serious problem because are contaminated by diverse industrial wastes among which are azo dyes used to dye a lot of products, and although there are various methods for the removal of these colorants do not are effective sufficiently, so that diverse techniques more sophisticated have been proposed, such as the elimination by sorption processes. Zeolites are materials found in various regions of Mexico and due to have a good sorption capacity are used to remove metals. In this paper a zeolitic material of the Chihuahua State was conditioned with FeCl{sub 3} and used for remove yellow 5 (tartrazine) in aqueous solutions, also the sorption capacity of modified zeolite with FeCl{sub 3} was examined for the azo dy yellow 5 in aqueous solutions. The sorption kinetics results was adapted to the pseudo second order model, indicating that the process is chemisorption, the sorption isotherms at different temperatures were adjusted to the Langmuir-Freundlich model, which usually it is adapt to systems with heterogeneous adsorbents. On the other hand, the ph value of the aqueous solutions does not affect on the sorption of this dye by the zeolitic material. (Author)

  14. The need for iron ore and the environmental Kuznets curve. Spain; 0176 La necesidad del mineral de hierro y la curva de Kuznets ambiental. El caso espanol

    Energy Technology Data Exchange (ETDEWEB)

    Torre de Palacios, L. de la

    2011-07-01

    Firstly, the environmental position of Spain with regard to steel consumption is defined according to the Kuznets curve (EKC) hypothesis. It is essential to undertake a complete environmental assessment of Spanish iron-ore consumption, to study the different steelmaking processes at this moment, emphasising the contribution of the high electric arc furnace. The use of recycled scrap, together with lower CO{sub 2} emissions, have succeeded in establishing Spain in a good environmental situation. (Author) 30 refs.

  15. Sorption of samarium in iron (II) and (III) phosphates in aqueous systems; Sorcion de samario en fosfatos de hierro (II) y (III) en sistemas acuosos

    Energy Technology Data Exchange (ETDEWEB)

    Diaz F, J C

    2006-07-01

    The radioactive residues that are stored in the radioactive confinements its need to stay isolated of the environment while the radioactivity levels be noxious. An important mechanism by which the radioactive residues can to reach the environment, it is the migration of these through the underground water. That it makes necessary the investigation of reactive materials that interacting with those radionuclides and that its are able to remove them from the watery resources. The synthesis and characterization of materials that can be useful in Environmental Chemistry are very important because its characteristics are exposed and its behavior in chemical phenomena as the sorption watery medium is necessary to use it in the environmental protection. In this work it was carried out the sorption study of the samarium III ion in the iron (II) and (III) phosphate; obtaining the sorption isotherms in function of pH, of the phosphate mass and of the concentration of the samarium ion using UV-visible spectroscopy to determine the removal percentage. The developed experiments show that as much the ferrous phosphate as the ferric phosphate present a great affinity by the samarium III, for what it use like reactive material in contention walls can be very viable because it sorption capacity has overcome 90% to pH values similar to those of the underground and also mentioning that the form to obtain these materials is very economic and simple. (Author)

  16. Los procesos técnicos de la cantería durante la Segunda Edad del Hierro en el occidente de la meseta

    OpenAIRE

    Rodríguez Hernández, Jesús

    2013-01-01

    This paper reconstructs the technical processes involved in producing the stone works made by the communities of Western Iberia during the Late Iron Age. For this study, we use both archaeological and ethnographic data. We analyze the characteristics of granite, the extraction process in the quarry, the available means of transport, the tools used and the carving process, focusing analysis on the zoomorphic sculptures known as “verracos”. Assessment of these technical aspects is essential for...

  17. Nuevas estrategias para incrementar la calidad nutricional de productos de panadería. Efecto sobre el contenido de fitatos y la biodisponibilidad de hierro en caco-2

    OpenAIRE

    Sanz Penella, Juan Mario

    2012-01-01

    [ES]Los productos de cereales con grano entero, en particular el pan, son fuentes de fibra dietética, vitaminas, minerales y compuestos fitoquímicos. Sin embargo, la biodisponibilidad de los minerales se afecta principalmente debido a la presencia de fitatos que reducen su absorción. El fitato se encuentra principalmente en los alimentos no procesados, pero puede ser degradado durante la germinación de las semillas o el procesado de alimentos. La hidrólisis del fitato a fosfatos de mio-inosit...

  18. Memory and linguistic/executive functions of children with Borderline Intellectual Functioning

    OpenAIRE

    Água Dias, Andrea; Albuquerque, Cristina P.; Simões, Mário Rodrigues

    2017-01-01

    Children with Borderline Intellectual Functioning (BIF) have received little research attention and have been studied in conjunction with Intellectual and Developmental Disabilities. The present study intends to broaden the knowledge on BIF, by analyzing domains such as verbal memory and visual memory, as well as tasks that rely simultaneously on memory, executive functions and language. A cross-sectional, comparison study was carried out between a group of 40 children with BIF (mean age = 10...

  19. 78 FR 61000 - Additional Designations, Foreign Narcotics Kingpin Designation Act

    Science.gov (United States)

    2013-10-02

    ...; Puerto de Hierro, Zapopan, Jalisco, Mexico; Fresno, CA; DOB 3 Apr 1972; alt. DOB 1960; alt. DOB 1966; POB..., Jaslico, Mexico; Vereda Del Canario 1, Guadalajara, Jalisco, Mexico; Puerto de Hierro, Zapopan, Jalisco...

  20. La intrusión de Cerro Redondo (Pérmico Inferior, Cordillera Ibérica, Zaragoza): reconstrucción 3D y modelo de emplazamiento

    OpenAIRE

    Majarena Serrano, Urbez; Gil Imaz, Andrés; Lago San José, Marceliano; Galé, Carlos

    2017-01-01

    La intrusión subvolcánica de Cerro Redondo (Cordillera Ibérica, Zaragoza), de edad Pérmico Inferior, muestra una composición dactíca, una naturaleza calcoalcalina y se caracteriza por presentar una marcada estructuración interna determinada por un bandeado subvertical y d e espaciado variable (1-25 cm), que se encuentra afectado por numerosos pliegues d e flujo magmático de distinta escala (desde centimétrica hasta hectométrica). El estudio cartográfico y de la anisotropia de la susceptib...

  1. Facies sedimentarias de la laguna kárstica de La Parra (Cuenca) durante los últimos 1600 años cal. BP.

    OpenAIRE

    Barreiro-Lostres, Fernando; Moreno Caballud, Ana; Valero-Garcés, Blas L.

    2014-01-01

    [ES] El análisis sedimentario y geoquímico llevado a cabo en los sondeos del lago kárstico de La Parra (Cordillera Ibérica, Cuenca) ilustra el comienzo de la sedimentación en la cuenca hace 1.600 años y su evolución sedimentaria, que principalmente está controlada por variaciones en la descarga detrítica hacia el lago. Un total de 11 facies sedimentarias han sido descritas, agrupadas en 3 unidades litoestratigráficas, compuestas en su mayor parte por carbonatos bandeados y m...

  2. 76 FR 6843 - Additional Designations, Foreign Narcotics Kingpin Designation Act

    Science.gov (United States)

    2011-02-08

    ..., Jaslico, Mexico; Vereda Del Canario 1, Guadalajara, Jalisco, Mexico; Puerto de Hierro, Zapopan, Jalisco..., Jalisco, Mexico; Puerto de Hierro, Zapopan, Jalisco, Mexico; Mexico City, Distrito Federal, Mexico.... RODRIGUEZ OLIVERA, Daniel (a.k.a. RODRIGUEZ MORFIN, Daniel), Puerto de Hierro, Zapopan, Jalisco, Mexico...

  3. Teledection techniques to find contaminated soils: study of a thru case: Quinto del Hierro, Almaden, Ciudad Real (Spain); Aplicaciones de la teledeteccion para la localizacion y cartografia de suelos contaminados: estudio de un caso real: el area con mineria romana de Quinto de Hierro (Almaden, Ciudad Real)

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, E.; Lacamara, R.; Almagro, J.

    1995-04-01

    The teledetection techniques have two main advantages: on the one hand they give us the possibility to watch at big earth surfaces; on the other and at the same time we can see some objects (such as the infrared field in the electromagnetic radiation), that are not evidence to the human eye. With these techniques we can solve every mentioned problems, e.g., the finding and delimitation of areas with contaminated soils. (Author)

  4. A PCR-based method for identification of bifidobacteria from the human alimentary tract at the species level

    NARCIS (Netherlands)

    Venema, K.; Maathuis, A.J.H.

    2003-01-01

    A polymerase chain reaction (PCR)-based method was developed for the identification of isolates of Bifidobacterium at the species level. Using two Bifidobacterium-specific primers directed against the 16S ribosomal gene (Bif164 and Bif662), a PCR product was obtained from the type strains of 12

  5. Petrography and geochemistry of the Dales Gorge banded iron formation: Paragenetic sequence, source and implications for palaeo-ocean chemistry

    DEFF Research Database (Denmark)

    Pecoits, E.; Gingras, M. K.; Barley, M. E.

    2009-01-01

    provenance. Nonetheless, when all the lithologies (i.e., source rocks, S and BIF macrobands) are evaluated together, continuous geochemical trends can be observed. This suggests that at least part of the precursor material of BIF macrobands was sourced from the same material that gave origin to the S...

  6. The effect of change in pH on the solubility 01 iron bis-glycinate chelate and other iron compounds

    OpenAIRE

    García-Casal, María Nieves; Layrisse, Miguel

    2001-01-01

    Efecto de cambios de pH sobre la solubilidad del hierro bis-glicinato quelado y de otros compuestos de hierro. Se estudió el efecto del cambio de pH de 2 a 6 sobre la solubilidad del hierro de sulfato ferroso, fumarato ferroso, hierro bis-glicinato quelado (Ferrochel) y ácido etilendiaminotetraacético sódico-férrico (NaFeEDTA). Se encontró que a pH 2 el hierro proveniente de sulfato, Ferrochel y NaFeEDTA estaba completamente soluble, mientras que para el fumarato ferroso solo el 75% del hierr...

  7. Two-Phase Reactive Transport Model CO2-Brine at Hontomín Technological Development Plant (Burgos); Modelo de Transporte Reactivo Bifásico CO –Salmuera en el Emplazamiento de la Planta de Desarrollo Tecnológico de Hontomín (Burgos)

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigo-Naharro, J.; Recreo-Jiménez, F.

    2015-07-01

    The option of storing CO2 in carbonate formations is a minority in the literature on CO2 Deep Geological Storage (CO2-DGS). However, there is sufficient bibliography on systems where CO2 natural accumulations have remained for centuries in carbonate formations (e.g. McElmo Dome, USA), as well as projects related to the enhanced oil recovery (Weyburn Project, Canada). Both cases can represent natural or industrial analogues of a CO2-DGS. The Technological Development Plant (TDP) at Hontomín (Burgos) was initially designed to inject supercritical CO2 or dissolved CO2 in a Lower Jurassic limestone-dolomite formation of the Burgos Platform, at 1500 m depth approximately. The Dogger Aquifer in the Paris Basin, together with the overlying Albian aquifer, is one of these potential analogues of the Underground Structure of Hontomín due to their stratigraphic, lithological and hydrogeological similarities. However, the drilling of the wells HI (injection) and HA (auscultation) in the TDP at Hontomín in 2014, which have allowed to access to the storage and seal formations, as well as the petrophysical measurements performed by CIUDEN and Fundación Instituto Petrofísico on core samples from both wells, and the hydraulic tests for the dynamic reservoir characterisation, have advised to include the more permeable formation levels of the Norian-Rhaetian “carniolas” in the initially selected storage formation. This formation is located at the bottom of the Sopeña dolomitic Fm., at a depth of 1595-1605 m in the well HI. The existence of sulphates (anhydrite and gypsum) in these levels introduces lithological and geochemical features not present in the Dogger aquifer of the Paris Basin which, in turn, advises to consider the lessons learned from the Weyburn Project. In this report a study of the system CO2–brine–storage rock, close to the well HI, is presented, where the deep aquifer of the Underground Structure of Hontomín could be affected in the chemical properties of the brine and in the petrophysical properties (porosity and permeability) of the reservoir and seal rocks, due to the heterogeneous solution of the carbonate-reservoir rocks and to the impact of the subsequent drying processes to the injection of supercritical CO2.

  8. Transferência de oxigênio em reatores de leito fluidizado com circulação em tubos concêntricos em meios bifásico e trifásico com variação da relação entre diâmetros

    OpenAIRE

    Araújo,Leandro Santos de; Dall'Aglio Sobrinho,Milton; Gebara,Dib

    2010-01-01

    A eficiência do reator de leito fluidizado com circulação em tubos concêntricos depende das condições hidrodinâmicas que influem na transferência de oxigênio ao biofilme. Este trabalho investigou a influência da relação entre diâmetros dos tubos e da concentração de meio suporte (areia), sobre o coeficiente global de transferência de oxigênio (K La). Os ensaios - em reatores de 2,6 m de altura, com diâmetro externo de 250 mm e internos de 100, 125, 150 e 200 mm - empregaram vazões de ar até 2...

  9. The prevalence of personality disorders in psychiatric outpatients with borderline intellectual functioning: Comparison with outpatients from regular mental health care and outpatients with mild intellectual disabilities.

    Science.gov (United States)

    Wieland, Jannelien; Van Den Brink, Annemarie; Zitman, Frans G

    2015-01-01

    There is little research on the subject of personality disorder (PD) in individuals with borderline intellectual functioning (BIF). Unlike in most countries, in the Netherlands, patients with BIF are eligible for specialized mental health care. This offers the unique possibility of examining the rates of PDs in patients, who in other countries are treated relatively invisibly in regular mental health care. To compare, in a naturalistic setting, the frequency of PD diagnoses in outpatients with BIF with outpatients from regular mental health care and outpatients with mild ID. We compared the rates of all DSM-IV-TR axis II PDs in outpatients with BIF (BIF group; n = 235) with rates of the same disorders in outpatients from regular mental health care (RMHC group; n = 1026) and outpatients with mild intellectual disability (ID) (mild ID group; n = 152) in a naturalistic cross-sectional anonymized medical chart review. Over half of the patients with BIF (52.8%) were diagnosed with a PD, compared with one in five in the RMHC group (19.3%) and one in three of the mild ID group (33.6%). All PD diagnoses, except for cluster A PDs and histrionic PDs, were most frequently diagnosed in the BIF group. PD NOS and borderline PD were the most frequently diagnosed PDs in BIF. The majority of PD patients had one or more comorbid axis I disorder. There is a high frequency of PD diagnoses in BIF outpatients in daily clinical practice. In anticipation of further scientific research, results suggest that PDs should not be overlooked in patients with BIF.

  10. Petrology and geochemistry of REE-rich Mafé banded iron formations (Bafia group, Cameroon)

    Science.gov (United States)

    Nkoumbou, Charles; Gentry, Fuh Calistus; Tchakounte Numbem, Jacqueline; Belle Ekwe Lobé, Yolande Vanessa; Nwagoum Keyamfé, Christin Steve

    2017-07-01

    Archaean-Paleoproterozoic foliated amphibole-gneisses and migmatites interstratified with amphibolites, pyroxeno-amphibolites and REE-rich banded-iron formations outcrop at Mafé, Ndikinimeki area. The foliation is nearly vertical due to tight folds. Flat-lying quartz-rich mica schists and quartzites, likely of Pan-African age, partly cover the formations. Among the Mafé BIFs, the oxide BIF facies shows white layers of quartz and black layers of magnetite and accessory hematite, whereas the silicate BIF facies is made up of thin discontinuous quartz layers alternating with larger garnet (almandine-spessartine) + chamosite + ilmenite ± Fe-talc layers. REE-rich oxide BIFs compositions are close to the East Pacific Rise (EPR) hydrothermal deposit; silicate BIFs plot midway between EPR and the associated amphibolite, accounting for a contamination by volcanic materials, in addition to the hydrothermal influence during their oceanic deposition. The association of an oceanic setting with alkaline and tholeiitic magmatism is typical of the Algoma-type BIF deposit. The REE-rich BIFs indices recorded at Mafé are interpreted as resulting from an Archaean-Paleoproterozoic mineralization.

  11. Effect of subacute poisoning with bifenthrin on locomotor activity, memory retention, haematological, biochemical and histopathological parameters in mice.

    Science.gov (United States)

    Nieradko-Iwanicka, B; Borzecki, A; Jodlowska-Jedrych, B

    2015-02-01

    Bifenthrin (BIF) is a pyrethroid (PYR) insecticide. The target point for PYR's toxic action are voltage sensitive sodium channels in the central nervous system (CNS). Intoxication with PYRs results in motor activity impairment and death in insects. Although PYRs are considered to be safe for mammals, there were numerous cases of pyrethroid poisoning in humans, animals and pets described. The general population is chronically exposed to PYRs via grain products, dust and indoor air. Therefore new questions arise: whether PYRs act in a dose-additive fashion in the course of subacute poisoning, are there other target organs (but brain) for BIF and if there is one common mechanism of its' toxic action in different organs. The objective of this work was to characterize the effect of BIF at the doses of 4 or 8 mg/kg injected intraperitoneally (i.p.) daily for 28 consecutive days on memory and motor activity, hematological, biochemical and histopathological parameters in mice. BIF at the doses of 8 mg/kg or 4 mg/kg of body mass was administered i.p. daily to the mice for 28 consecutive days. Motor function was measured on day 1, 7, 14 and 28 and memory retention was tested in a passive avoidance task on day 2, 7, 14 and 28. BIF significantly impaired memory retention on day 2. BIF decreased locomotor activity at every stage of the experiment in a single dose depending manner. No behavioral cumulative effect was observed. Subacute poisoning with the higher dose of BIF caused anaemia, elevated white blood cell count (WBC), elevated alanine transaminase (ALT), superoxide dismuthase (SOD), and decreased glutathione peroxidase (GPx) activity. Lymphocyte infiltrates were visualized in the livers. subacute poisoning with BIF decreases locomotor activity in a single dose proportionate manner. BIF damages also the liver and alters blood morphology. The possible common mechanism of these effects can be oxidative stress.

  12. Evaluation of iron phosphate (III) as reactive material for removal of uranium in water; Evaluacion del fosfato de hierro (III) como material reactivo para la remocion de uranio en agua

    Energy Technology Data Exchange (ETDEWEB)

    Solis M, L

    2004-02-01

    The levels of toxic metals in the atmosphere are topic of growing interest. This has provoked that the legislation is stricter, for that that the industry and centers of investigation has worried and busy of to look for and to develop more effective methods for the control of the contamination, with the purpose of being inside this levels. The phosphate compounds are being investigated for the removal of pollutants of the water and soil. In this work, it was synthesized to the ferric phosphate in a simple way in the laboratory, obtaining high grade of purity and yield. The characterization of this product was in a physicochemical way and of surface, through diverse analytical techniques. In the first place, the physicochemical characterization was carried out for Scanning Electron Microscopy of High Vacuum, X-ray diffraction, Infrared Spectroscopy with Fourier Transform, and Thermal gravimetric Analysis, the surface characterization was carried out for analysis of the surface area, determination of the isoelectric point by potentiometric and of mass titrations. The previous techniques allowed to identify the ferric phosphate synthesized as a compound amorphous beige color, with a relationship of atoms Fe:1, P:1, O:4, which showed connections P-O and went stable to changes of temperature. The surface area it was of 21 g / m{sup 2}, the isoelectric point corresponded to a p H of 1.5, which coincided so much by potentiometric like by mass titration. The number of active sites was of 106 sites /nm{sup 2}. After the characterization of the ferric phosphate the compound was evaluated as reactive material for the removal of uranyl ions through sorption tests. The kinetics of hydration showed that the product requires of 24 hours to saturate the sites capable of to be hydrated. The sorption kinetics required 22 hours of contact to reach the maximum sorption of uranyl ions for the ferric phosphate. The sorption isotherms showed that not significant difference exists when using 0.05, 0.1, 0.15 and 0.2 g of ferric phosphate, for that 0.1 g of material was used. The isotherms were carried out in function of the p H of the uranyl solutions and of the mass of the ferric phosphate where is observed that to p H 3.5-5 the percentage of removal is the highest reaching bigger values to 90%. Finally the data of the sorption of uranium was adjusted to the pattern of Langmuir. (Author)

  13. Mechanical milling of a nano structured ductile iron powder under dry, wet and cryogenic atmospheres; Proceso de molturacion mecanica en medio seco, humedo y criogenico de polvo de hierro ductil nanoestructurado

    Energy Technology Data Exchange (ETDEWEB)

    Cinca, N.; Hurtado, E.; Cano, I. G.; Guilemany, J. M.

    2011-07-01

    The main objective of this study, is to obtain an effective particle and grain size reduction of a nano structured iron powder by mechanical milling under different milling media. One of the main challenges in this study is to work with this material of great ductility.The variables of the study to be optimized have been the following: speed of rotation, powder to ball ratio (PBR) and the percentage of control agent to induce an effective powder fracturing in front of cold welding. The powder has been characterized by a Laser Diffraction Particle Size Analyser, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and, X-ray diffraction.Through the comparative study, it is found that operating under dry milling conditions: there is a more effective particle size reduction of 43 % and grain size reduction of 62 %. In wet conditions has been reduced the amount of oxide, as well as to obtain a more homogenous distribution of the resulting powder. The results under cryogenic media is presented as promising. (Author) 15 refs.

  14. Control of the flame front advance in a sintering bed of iron ores; Control del avance del frente de llama en el lecho de sinterizacion de minerales de hierro

    Energy Technology Data Exchange (ETDEWEB)

    Cores, A.; Mochon, J.; Ruiz-Bustinza, I.; Parra, R.

    2010-07-01

    A sintering pan of 40 cm cubed is loaded with a mixture of iron ores, limestone and coke weighing 110 kg in a sintering pilot plant. In this sintering pan, a series of thermocouples have been introduced at different depths. Tests have been carried out to study the width of the combustion zone and the maximum temperature of the flame front across the sintering bed. For the analysis of the results, a data acquisition system was used. This consisted of two modules connected in serie, for performing the analogue-digital conversion. The analogue entry point is the exit point of the thermocouples and the digital exit point was the temperature average. A computer was used for conserving and storing the data and for carrying out interpolations, simulating the state and evolution of the flame front across the bed. (Author) 21 refs.

  15. Study of granitic biotites by X-ray fluorescence analysis: determination of iron, manganese, titanium, calcium, potassium, silicon and aluminium; Estudio de biotitas graniticas por fluorescencia de rayos X: Determinacion de hierro, manganeso, titanio, calcio, potasio, silicio y aluminio

    Energy Technology Data Exchange (ETDEWEB)

    Toubes, R. O.; Bermudez Polonio, J.

    1968-07-01

    A method for the quantitative determination of iron, manganese, titanium, calcium potassium, silicon, and aluminium, is reported, Sample preparation is carried out by the miniature flux technique, and rubidium is used as internal standard for silicon and aluminium. (Author) 5 refs.

  16. Estudio de casos Aislamiento de bacterias del hierro y azufre como productoras de biodeterioro o corrosión anaeróbica en tuberías y daño a otros materiales

    Directory of Open Access Journals (Sweden)

    Virginia Montero Campos

    Full Text Available Los procesos de biodeterioro son reconocidos actualmente como una de las mayores causas de deterioro en superficies de diversos materiales, queafectan a una gran cantidad y diversos tipos de industrias. Una superficie metálica en contacto con agua o tierra experimenta una serie de cambios biológicos e inorgánicos que constituyen el fouling. La posterior secuencia de cambios biológicos es debido a la adherencia irreversible de diferentes tipos de microorganismos sobre el metal a través del material polimérico extracelular, constituyendo ello, el biofouling. La biocorrosión y el biofouling de las superficies se deben a procesos biológicos y electroquímicos que ocurren mediante la participación de microorganismos adheridos a las superficies a través de biofilmes. Estas películas biológicas modifican las condiciones de la interfase metal/solución, formando una barrera al contacto entre el metal o material y el medio circundante, se considera que la corrosión microbiológica transcurre entonces sobre una superficie modificada con características fisicoquímicas y biológicas muy particulares y condicionadas, donde no se puede interpretar con los mismos parámetros de un proceso de corrosión inorgánica.

  17. Efecto del tipo de lactancia durante el primer año de vida sobre el estado de hierro y el desarrollo físico y psicológico del niño

    OpenAIRE

    Bedmar Carretero, Cristina

    2012-01-01

    L’objectiu d’aquest estudi va ser valorar el desenvolupament del nen durant el primer any de vida en funció del tipus de lactància realitzada durant el primer semestre y de la dosis de ferro administrada durant el segon semestre. Hem observat que el 75,5% dels nens realitzen lactància materna exclusiva al néixer y el 16,5% la mantenen fins als 6 mesos. El 39,5% tenen alguna mutació en el gen HFE. La prevalença de dèficit de ferro y anèmia ferropènica es del 4,5% y 2,5% als 6 mesos y del 9,2% ...

  18. Origen del drenaje ácido de minas y problemática ambiental de las escombreras de peña del hierro (Faja Pirítica Ibérica)

    OpenAIRE

    Romero Baena, Antonio

    2005-01-01

    La explotación de los recursos minerales ha sido una de las actividades más importantes para el desarrollo de la humanidad. Desde los tiempos prehistóricos hasta la actualidad la explotación y el uso de rocas y minerales han jugado siempre un papel mu ... La extracción de los recursos minerales conlleva una serie de alteraciones medioambientales que a veces pueden llegar a ser muy negativas; y aunque en las últimas décadas se ha tomado conciencia de este deterioro, es en la actualidad cua...

  19. Aplicación de la escoria de fundición de hierro como agregado en las mezclas de hormigón para pavimentos rígidos

    OpenAIRE

    Nasimba Chanataxi, Diego Andrés

    2017-01-01

    n this research article compares the resistance to compression and bending of a conventional concrete used for the construction of roads (rigid pavement), with a concrete that contains slag of iron smelting in partial replacement of the aggregate thickness (gravel) in percentages of 5%, 10%, 15%. With this objective, concrete mixtures and their respective cylindrical specimens and standard beams were elaborated to perform the corresponding compression and bending tests. It was concluded that ...

  20. Diseño racional de electrodos positivos de alto rendimiento de fosfato de litio y hierro con polímero conductor para baterías de ión litio

    OpenAIRE

    Cíntora-Juárez, Daniel

    2016-01-01

    LiFePO4 has been pointed out as a next-generation active material for lithium-ion (Li-ion) batteries and its performance has been progressively improved mostly by optimizing the synthesis conditions of this cathode material in order to obtain carbon‑coated nano-particles of controlled purity. Nevertheless, there is still the need for improving the composition and the preparation methods of LiFePO4-based electrodes, which is paramount for maximizing the capacity at high charge/discharge rates....

  1. Removal of blue 1 dye of aqueous solutions with a modified clay with iron chloride; Remocion de colorante azul 1 de soluciones acuosas con una arcilla modificada con cloruro de hierro

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez H, K. A.

    2012-07-01

    At the present time, several technologies have been proposed to remove dyes from water, adsorption is one of the most feasible methods and adsorbents with different properties, such as activated carbon, zeolites, clays and hydrogels among others. In this work, the sorption behavior of blue 1 dye by a natural clay from a site located in the Center-East of Mexico, and other modified with iron chloride were determined. The materials were characterized by X-ray diffraction to analyze its crystal structure, by scanning electron microscopy and elemental microanalysis of energy dispersive X-ray spectrometry to determine the composition and morphology, and the zero point charges were also determined to know the charge distribution on the surface of the clay. The ph effect, contact time, dye concentration and temperature were the parameters considered in this study. The results showed that clay does not suffer any important changes in its structure after the chemical treatments (modification with ferric chloride and contact with blue 1 solutions). The ph influences lightly the adsorption of the dye with natural clay, but the same effect is not observed in the ferric modified clay among the factor ph 6 and 8. The equilibrium time and the sorption capacity for natural clay were 48 hours and 6.16 mg/g, while for the ferric clay were 24 hours and 14.22 mg/g. Adsorption kinetics results were best adjusted to the pseudo first and pseudo second order models. Adsorption isotherms were best adjusted to the Langmuir model, indicating that both clays have a homogeneous surface. Thermodynamic parameters (E, {Delta}S and {Delta}G and {Delta}H) were calculated for the dye adsorption by the natural clay using data of the adsorption kinetics at temperatures between 20 and 50 C, indicating that the adsorption process is exothermic. For the case of ferric clay, it was not possible to calculate these thermodynamic parameters because the adsorption capacities were similar in the range of selected temperatures. (Author)

  2. Efecto de la adición de una turba comercial en la asimilabilidad de cobre, zinc, hierro, manganeso de un suelo en el que se ha cultivado trigo

    OpenAIRE

    Almendros García, Patricia; Álvarez Álvarez, José Manuel; González Rodríguez, Demetrio; Obrador Pérez, Ana Francisca

    2014-01-01

    Se ha estudiado el efecto de la adición de diferentes cantidades de una turba comercial (con un 80 % de turba rubia y un 20% de turba negra) en la asimilabilidad de los elementos nutritivos en un suelo calcáreo en el que se cultivó trigo. Para ello se determinaron los contenidos en N, P y K, así como las concentraciones totales y potencialmente asimilables para las plantas de los micronutrientes Cu, Zn, Fe y Mn. También se determinó el rendimiento en grano y el índice de cosecha del cultivo d...

  3. Sorption of Fe{sup 3+} , Co{sup 2+} , Ce{sup 3+} , Cs{sup +} and Ba{sup 2+} in zeolite X.; Sorcion de Hierro (III), Cobalto (II), Cerio (III), Cesio (I), Bario (II) en Zeolita X.

    Energy Technology Data Exchange (ETDEWEB)

    Martinez M, V

    1994-12-31

    The sorption behavior of Fe{sup 3+} , Co{sup 2+} , Ce{sup 3+} , Cs{sup +} , and Ba{sup 2+} in aqueous solutions, was studied in presence of zeolite X. Solutions of Fe(NO{sub 3}){sub 3} . 9 H{sub 2} O, Co(NO{sub 3}){sub 2} . 6 H{sub 2} O, Ce(NO{sub 3}){sub 3} . 6 H{sub 2} O, Cs NO{sub 3} and Ba(NO{sub 3}){sub 2} were labelled with the respectively radioactive isotopes Fe{sup 59} , Co{sup 60}, Cs{sup 134}, Ba{sup 139} and Ce{sup 141}. 20 ml. of each solution was left in contact with 200 mg. of zeolite for different periods. Later the zeolites were separated by centrifugation from the aqueous solutions and the radioactivity of the aqueous phases was measured with a NaI(Tl) solid-state well detector coupled to a single-channel Picker analyzer or with a Gel hyper pure solid-state detector coupled to a 2048 channel pulse height analyzer. When Cs{sup +} in the aqueous solutions was left in contact with zeolite X it was found that it does not occupy all cationic sites in the zeolite due to the ionic radium effect. A similar behavior was found for the divalent ions. In all cases, when the pH was not controlled, the zeolite lost part of its crystallinity and when the divalent ions were exchanged again by Na{sup +}, the zeolite recovered completely its crystallinity. During the sorption, the ionic radius, and the charge are important parameters as well as the pH. When the pH of the solution was adjusted between 6.5 - 7.0 the crystallinity was maintained in some cases. For Fe{sup 3+} the crystallinity after the ion exchange was 94 % and when the pH was not adjusted the crystallinity was completely lost. It was found as well that the zeolite X induces the formation of H{sub 3} O{sup +} which competes with the cations for the sites in the zeolite. (Author).

  4. Spectrophotometric determination of aluminium in presence of iron with eriochrome cyanine R. Essays with a decolorated reagent; Determinacion espectrofotometrica de aluminio en presencia de hierro con eriocromocianina R. Ensayos con un reactivo decolorado

    Energy Technology Data Exchange (ETDEWEB)

    Barrachina Gomez, M; Gasco Sanchez, L; Fernandez Cellini, R

    1962-07-01

    The behaviour of the extinction coefficient of aqueous solutions of Eriochrome Cyanine R is studied. It is found that at pH 5-6 the diluted acid solutions decolorate rapidly according to an exponential law (538 m{mu}). The fact that the decoloree solutions go on still reacting with the aluminium has. (Author) 12 refs.

  5. The iron, aluminate and jarosite deposits in Riazas area as potential source of arsenic in groundwater; Los yacimientos de hierro, alunita y jarosita de la zona de Riaza como posible origen del arsenico en las aguas subterraneas

    Energy Technology Data Exchange (ETDEWEB)

    Leal Meca, M.; Lilo Ramos, J.

    2009-07-01

    Arsenic in concentrations above the legal limit of 10 {mu}g/l has been detected in groundwaters of the Duero Cenozoic Basin. The origin of arsenic is related to sedimentary units with arsenic content above the background value of 28.5 mg/kg. Thus, iron-rich deposits located at the base of Cenozoic succession may constitute a potential source of arsenic in the groundwaters. Three outcrops of iron-rich conglomerates in the Riazas area of Segovia province (one in El Negredo and two in Madriguera) have been studied to determine the significance of these materials as a potential source of arsenic in groundwater. These outcrops occur above an unconformity separating them from strongly altered Paleozoic slates, rich in alunite and jarosite. The work is based in geochemical (trace elements detection by INAA) and mineralogical analyses (through XRD-EDAX and ESEM) of 18 samples of altered slates and materials of ferriferrous deposits. Besides, 3 water samples from springs have subjected to hydrochemical analysis to establish major ionic species and trace elements. Although mineralogical study reveals that arsenic occurs in iron oxides and high arsenic concentrations have been identified in rocks of El Negredo (up to 361 mg/kg, average 143.3 mg/kg), the arsenic concentrations in Ca-Mg-HCO{sub 3} - water type are always lower than 10 {mu}g/l. Therefore, it does not seem to be probable that these deposits act as arsenic source, at least at the present physic-chemical conditions.(Author) 37 refs.

  6. Synthesis and characterization of conditioned carbon with iron nanoparticles for the arsenic removal in aqueous phase; Sintesis y caracterizacion de carbon acondicionado con nanoparticulas de hierro para la remocion de arsenico en fase acuosa

    Energy Technology Data Exchange (ETDEWEB)

    Flores C, D. O.

    2012-07-01

    Using pineapple husks conditioned with carboxymethylcellulose, hexamine and ferric nitrate, a carbonaceous material was obtained with nanoparticles of Fe (C Fe), which was characterized and tested for arsenic removal in the aqueous phase. The microscopic study showed spheres 4 microns and filaments 100 nm wide, so as iron particles whose diameter decreases to an average of 38.81 nm, when pyrolysis time was increased to 180 min. their distribution in the carbonaceous matrix is homogeneous. According to energy dispersive X-ray spectroscopy, C Fe contains C (82.29%), O (7.23%), K (0.68%), Ca (3.77%) and Fe (6.25%) and its diffraction pattern shows the characteristic peak of Fe (0), which is not observed in the coal without iron. By neutron activation analysis were quantified Al, Br, Ce, Co, Cr, Cs, Eu, Hf, K, Mg, Mn, Na, Rb, Sb, Sc and Zn, they can be involved in the process of sorption of As (v) forming surface active sites. For C Fe and C B characterized by Fourier transform infrared spectrometry, groups C-H, C=O, C=C, -Nh, NH{sub 2}, isocyanate and isonitrile were found, the last two were formed by the present hexamine. X-ray photoelectron spectroscopy showed energy states of C 1 and O 1 in pineapple shell washed, shell conditioned with iron, C Fe at different times and the pyrolysis coal without iron (C B). The material C Fe 180 presented a specific area of 167 m{sup 2}/g and 7.12 {+-} 1 sites/nm{sup 2} isoelectric point while pH{sub i} = 11.1 C B is 98.80 m{sup 2}/g specific area and 1.5 {+-} 1 sites/nm{sup 2} and pH{sub i} = 10.6, being favorable to the sorption process. The highest removal of As(v) for both materials was at ph = 2, fitting the kinetic data to pseudo-second order model. The isotherms as a function of concentration were adjusted to Freundlich model indicating multilayer chemisorption at specific sites of a heterogeneous medium. Characterization by scanning electron microscopy after the sample sorption Fe nanoparticles remain in the carbonaceous matrix being not affected by the agitation of ph change during the removal process. (Author)

  7. Simultaneous sorption of fluoride and arsenic ions (V) in a naturally occurring material modified with iron and aluminum; Sorcion simultanea de iones fluoruros y arsenico (V) en un material de origen natural modificado con hierro y aluminio

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez M, G.

    2016-07-01

    In this research, two materials, zeolite and pozzolans from the States of Oaxaca and Mexico, were used respectively, which were modified to evaluate their efficiencies to remove F and As(V) ions from solution and natural water. The materials were modified with iron and aluminum using an electrochemical cell, and with the hydroxides formed with iron and aluminum chloride solutions. The natural and modified materials were characterized by X-ray diffraction, scanning electron microscopy with energy X-ray disperse spectroscopy analysis, specific area and the point of zero charge (pHzpc). F- and As(V) adsorption properties of both materials were investigated. Experimental data on the sorption processes of F- ions by modified zeolite and pozzolans were adjusted to the kinetic models of pseudo-second-order (q e, 0408 mg /g K, 4.33 g / mg h) and Lagergen (q e, 0.807 mg/g K L, 1.83 1/min), respectively. Both materials showed the best fit to the Freundlich isotherm, Kf, 0.33 and 0.64 (mg/g) (L/mg) for pozzolans and zeolite respectively; suggesting a physical adsorption process on a heterogeneous material. Experimental adsorption capacities of pozzolans and modified zeolite for F ions were 0.36 and 0.83 mg/g respectively. The results of the kinetics of adsorption of As(V) were treated with the Largergren, pseudo-second-order and Elovich models; however the adsorption rate was high and consequently the rate constants could not be calculated. The isotherms data were fitted to the Freundlich model and the constants Kf were 6.24 and 11.15 (mg/g) (L/mg) for pozzolans and zeolite respectively. The thermodynamic parameters of the adsorption processes suggest endothermic adsorption for F- ions by both materials and for As(V) by the pozzolans. The free energy values ΔG indicate spontaneous processes and not spontaneous for F- ions by pozzolans. The adsorption of As (V) by the pozzolans presented an exothermic and spontaneous behavior. Finally, a study was performed in columns with the modified zeolite and natural water with F- (3.3 mg/L) and As (4.65 mg/L) ions. Experimental data of F- ions adsorption were fitted to the Bohart-Adams and Thomas models with 1.5 cm bed depth; the adsorption capacity was lower than the capacity obtained with F- solutions. The adsorption data for As was adjusted to Bohart-Adams model, the adsorption capacity was higher than the capacity obtained with As solutions. The modified zeolite with the electrochemical method was more efficient to remove F- and As ions than modified pozzolans with iron and aluminum hydroxides, therefore it can be used as an alternative to remove these ions from the water. (Author)

  8. La vida a las puertas de la jaula de hierro. Relaciones de poder inherentes a las prácticas de participación en el Tercer Sector

    Directory of Open Access Journals (Sweden)

    Miguel Angel Sahagún-Padilla

    2009-11-01

    Full Text Available In this work I offer an overview of my doctoral research on forms of power that are inherent to participatory practices in Third Sector organizations. The research problem has been placed within a framework that intends to address the overlapping character of power phenomena and organizational phenomena. The theoretical framework draws from the works of Foucault (power, Bourdieu (habitus, field, Barchrach and Baratz (non-decision and Goffman (footing. The method consists of an ethnographic study which is focused on the interpretation of practices. Results are deployed in the form of three grand maps, each of which belongs to a specific analytic layer: a intersectorial exchanges and their effects; b organizational configuration and functioning and c symbolic aspects. Conclusions underline the neutralizing effects of Third Sector as a space for participation. 

  9. Relation between feeding mechanisms and solidification mode in 380 aluminium alloy with different iron contents; Relacion entre los mecanismos de alimentacion y el modo de solidificacion en una aleacion de aluminio 380 con distintos contenidos de hierro

    Energy Technology Data Exchange (ETDEWEB)

    Tovio, D. O.; Gonzalez, A.C.; Mugica, G. W.; Cuyas, J. C.

    2003-07-01

    In the present work the effect of iron (0.15, 0.42 and 0.86%) content in feeding mechanisms for 380 aluminium alloy has been studied. The feeding capacity has been evaluated by a device that produces a barrier removable to allowing the movement of the inter dendritic liquid. The results show the flow of different quantity of liquid, it depends of the temperature of operating the device and of the iron content. For minimum and maximum iron content, the inter dendritic and bursts feeding mechanisms are fundamentally involved, for 0.42% of iron the feeding mechanisms was the inter dendritic. The authors establish this behavior by the solidification mode of alloy, which promotes the presence of particles of Si or plates of b-Al{sub 3}FeDi phase, in the inter dendritic channels and produce the different feeding mechanisms. (Author) 15 refs.

  10. APLICACIÓN DE LA TEORÍA DE COLAS Y DE LA SIMULACIÓN AL EMBARQUE DE MINERAL DE HIERRO Y MANGANESO EN LA TERMINAL MARÍTIMA DE PONTA DA MADEIRA

    OpenAIRE

    Camelo, Gustavo Rossa; Coelho, Antônio Sérgio; Borges, Renata Massoli

    2010-01-01

    De entre las principales técnicas disponibles utilizadas en procesos de análisis y resolución de problemas sobresalen la Teoría de Colas y la Teoría de la Simulación: aquella, un método analítico para abordaje del asunto; esta, una técnica de modelaje que busca mejor representar el sistema en estudio. El uso de estas técnicas de modelaje, para resoluciones de problemas complejos y dinámicos, tiene crecido mucho en los últimos años, aunque, hay una carencia perceptible en la literatura de apli...

  11. Capacidad de Remoción de los Residuos de la Fermentación Cervecera Modificados por Óxidos de Hierro Frente a un Colorante Azo Bifuncional Reactivo de la Industria Textil

    OpenAIRE

    Tapia Montesinos, María Alejandra

    2017-01-01

    Los procesos de la industria textil se encuentran entre los más nocivos para el medio ambiente, ya que producen grandes cantidades de aguas residuales coloreadas muy contaminadas. En el presente trabajo se emplearon los residuos de la fermentación cervecera para determinar el residuo con mayor porcentaje de remoción del colorante azo bifuncional reactivo (Synozol Red K3BS), siendo el de mejor rendimiento el bagazo de grano de tamaño de partícula entre 75 – 150 μm (99.29% de ...

  12. Los narûs (kudurrus babilónicos del Bronce Final y el Hierro = The Babylonian narû (kudurrētu in Late Bronze and Iron Age

    Directory of Open Access Journals (Sweden)

    Sara Arroyo Cuadra

    2016-11-01

    Full Text Available Los narû babilónicos, conocidos tradicionalmente con el nombre de kudurrētu (en singular kudurru, fueron unos monumentos de piedra que incluían representaciones divinas encarnadas generalmente por sus emblemas y escenas con figuras antropomorfas, junto a un texto administrativo sobre transacciones  de tierras. Estos narû vieron la luz con la Dinastía Casita de Babilonia y dejaron de utilizarse en el período Neo-babilónico (ca. 1400-650 a.C.. La gran mayoría de los ejemplares se ha descubierto en Susa en contextos arqueológicos descontextualizados, pero los ejemplares hallados in situ nos hablan de que su dispersión geográfica original hay que situarla en el territorio de la Baja Mesopotamia. Hemos emprendido una investigación orientada a estudiar el corpus de estos monumentos integrado hasta el momento por 178 ejemplares, adoptando una postura interdisciplinar que incluye el análisis de la información que transmiten sus textos, iconografía, materialidad y contexto arqueológico. Por ello, a lo largo del presente artículo se intentará definir el criterio de adscripción de los ejemplares conocidos a dicho corpus según sus propias inscripciones y los estudios previos de  otros autores. A continuación, se hablará de las circunstancias que pudieron motivar su aparición y de los eventos histórico-políticos que pudieron influir en su evolución, así como del ámbito geográfico en que estuvieron vigentes. Después, se analizará el contenido de sus inscripciones y la simbología de su iconografía para, aportar, finalmente, un estudio comparativo entre textos y símbolos, quedando todo ello plasmado en un apartado final de conclusiones.Babylonian narû, traditionally named kudurrētu, were stone monuments with divine representations (generally through its divine emblems and figurative scenes with anthropomorphic figures, together with an administrative text about a land grant. These narû originated in Kassite Babylon and were being used until Neo-Babylonian Period (ca. 1400-650 a.C.. The majority of them have been discovered in Susa without contextualizing, because the items which have been found in situ tell us that their original placement was Southern Mesopotamia. In this paper, the main aim is to study the narû corpus, currently formed by 178 items, in a interdisciplinar way, that is to say, analyzing the information which their texts, iconography, materiality, archaeological context, etc. give us. This is the reason why the author of this article will try to define the corpus according to their own inscriptions and according to the main previous studies of several scholars on this subject. Then, the circumstances which could cause the rising and the historical and political events which could affect their development will be studied, together with the geographical context which they expand on. Subsequently, the content of their inscripctions and symbology of their iconography will be analyzed in a comparative approach. Finally, the main results of this research will be shown in a conclusions paragraph.

  13. Population Parameters of Blainville’s and Cuvier’s Beaked Whales

    Science.gov (United States)

    2014-09-30

    waters, they are usually difficult to study. El Hierro (Canary Islands) holds resident populations of Blainville’s and Cuvier’s beaked whales in...surveys off El Hierro , according to plan. Four of these cruises took place since the last report in September 2013, summing 38 days of fieldwork performed...marks as to be individually recognizable. 3 Publication of results of the ONR funded cetacean research in El Hierro in 2014 Peer reviewed

  14. Population Parameters of Blainvilles and Cuviers Beaked Whales

    Science.gov (United States)

    2015-09-30

    cetacean populations. Long-term monitoring of beaked whale populations in El Hierro , a nearly pristine habitat far from areas of sonar testing or...marine industry, enables valuable studies of demographic trends and life history dictated mainly by natural parameters. El Hierro is in process of...functioning (expected in 2018-2019), it is essential to continue monitoring the populations in El Hierro to obtain an uninterrupted long-term dataset of

  15. Hybrid Nanotechnologies for Detection and Synergistic Therapies for Breast Cancer

    Science.gov (United States)

    2012-10-01

    Hierro Majadahonda, 28222 Madrid, Spain, the §Cancer Research Center, Sanford-Burnham Medical Research Institute, La Jolla, California 92037, and the...correspondence should be addressed: Unidad de Inmunología Molecular, Hospital Universitario Puerta de Hierro , C/Manuel de Falla 1, 28222 Majadahonda, Madrid...accordance with the guidelines of the Hospital Universitario Puerta de Hierro Ani- mal Care and Use Committee and performed in accordance with Spanish

  16. Browse Title Index

    African Journals Online (AJOL)

    Bif3) Thin Films, Abstract. FI Ezema, MN Nnabuchi. Vol 19, No 1-2 (2007): AFORNET Special Edition, Optimizing productivity on multistage timber harvesting systems. A case of Shume/Mkumbara system, Tanzania ...

  17. A tick B-cell inhibitory protein from salivary glands of the hard tick, Hyalomma asiaticum asiaticum

    International Nuclear Information System (INIS)

    Yu Da; Liang Jiangguo; Yu Haining; Wu Haifeng; Xu Chunhua; Liu Jingze; Lai Ren

    2006-01-01

    Some studies done to date suggest that B-cell inhibitory factor occurred in tick saliva. In this study, a novel protein having B-cell inhibitory activity was purified and characterized from the salivary glands of the hard tick, Hyalomma asiaticum asiaticum. This protein was named B-cell inhibitory factor (BIF). The cDNA encoding BIF was cloned by cDNA library screening. The predicted protein from the cDNA sequence is composed of 138 amino acids including the mature BIF. No similarity was found by Blast search. The lipopolysaccharide-induced B-cell proliferation was inhibited by BIF. This is First report of the identification and characterization of B-cell inhibitory protein from tick. The current study facilitates the study of identifying the interaction among tick, Borrelia burgdorferi, the causative agent of Lyme disease, and host

  18. Mineralogy and geochemistry of banded iron formation and iron ...

    Indian Academy of Sciences (India)

    The geological complexities of banded iron formation (BIF) and associated iron ores of Jilling–. Langalata iron ore ...... sure to sea water. Uranium in these samples varies ..... Ce oxidation and removal (Elderfield and Greaves. 1982; De Baar et ...

  19. Memory and linguistic/executive functions of children with borderline intellectual functioning.

    Science.gov (United States)

    Água Dias, Andrea B; Albuquerque, Cristina P; Simões, Mário R

    2017-11-08

    Children with Borderline Intellectual Functioning (BIF) have received a minimal amount of research attention and have been studied in conjunction with Intellectual and Developmental Disabilities. The present study intends to broaden the knowledge of BIF, by analyzing domains such as verbal memory and visual memory, as well as tasks that rely simultaneously on memory, executive functions, and language. A cross-sectional, comparison study was carried out between a group of 40 children with BIF (mean age = 10.03; 24 male and 16 female), and a control group of 40 normal children of the same age, gender, and socioeconomic level as the BIF group. The WISC-III Full Scale IQs of the BIF group ranged from 71 to 84. The following instruments were used: Word List, Narrative Memory, Rey Complex Figure, Face Memory, Rapid Naming (both RAN and RAS tests), and Verbal Fluency. The results showed deficits in children with BIF in verbal short-term memory, rapid naming, phonemic verbal fluency, and visual short-term memory, specifically in a visual recognition task, when compared with the control group. Long-term verbal memory was impaired only in older children with BIF and long-term visual memory showed no deficit. Verbal short-term memory stands out as a limitation and visual long-term memory as a strength. Correlations between the WISC-III and neuropsychological tests scores were predominantly low. The study expands the neuropsychological characterization of children with BIF and the implications of the deficits and strengths are stressed.

  20. Size ratio performance in detecting cerebral aneurysm rupture status is insensitive to small vessel removal.

    Science.gov (United States)

    Lauric, Alexandra; Baharoglu, Merih I; Malek, Adel M

    2013-04-01

    The variable definition of size ratio (SR) for sidewall (SW) vs bifurcation (BIF) aneurysms raises confusion for lesions harboring small branches, such as carotid ophthalmic or posterior communicating locations. These aneurysms are considered SW by many clinicians, but SR methodology classifies them as BIF. To evaluate the effect of ignoring small vessels and SW vs stringent BIF labeling on SR ruptured aneurysm detection performance in borderline aneurysms with small branches, and to reconcile SR-based labeling with clinical SW/BIF classification. Catheter rotational angiographic datasets of 134 consecutive aneurysms (60 ruptured) were automatically measured in 3-dimensional. Stringent BIF labeling was applied to clinically labeled aneurysms, with 21 aneurysms switching label from SW to BIF. Parent vessel size was evaluated both taking into account, and ignoring, small vessels. SR was defined accordingly as the ratio between aneurysm and parent vessel sizes. Univariate and multivariate statistics identified significant features. The square of the correlation coefficient (R(2)) was reported for bivariate analysis of alternative SR calculations. Regardless of SW/BIF labeling method, SR was equally significant in discriminating aneurysm ruptured status (P analysis of alternative SR had a high correlation of R(2) = 0.94 on the whole dataset, and R = 0.98 on the 21 borderline aneurysms. Ignoring small branches from SR calculation maintains rupture status detection performance, while reducing postprocessing complexity and removing labeling ambiguity. Aneurysms adjacent to these vessels can be considered SW for morphometric analysis. It is reasonable to use the clinical SW/BIF labeling when using SR for rupture risk evaluation.

  1. Original article Parenting style and locus of control, motivation, and school adaptation among students with borderline intellectual functioning

    Directory of Open Access Journals (Sweden)

    Anna Maria Jankowska

    2014-12-01

    Full Text Available Background Parenting style impacts children’s psychosocial development. Students with borderline intellectual functioning (BIF are especially sensitive to the quality of parental care. The objective of this study was to compare parenting styles of mothers of children with BIF and mothers of typically developing peers, and establish associations between parenting styles and children’s psychosocial traits, which determine their school functioning. Participants and procedure Forty-two primary school students in Grades 4 to 6, their teachers, and mothers participated in the study. Based on their IQ level they comprised two groups: students with BIF (criterion group; n = 21 and students with average IQ (comparison group; n = 21. A series of measures were used to assess mothers’ parenting style and students’ psychosocial traits. Questionnaires measuring students’ psychosocial pro­perties were administered to children and their teachers in order to compare their perspectives. Results Mothers of children with BIF in comparison to mothers in the control group presented greater inclinations towards over-parenting. Based on self-reports, students with BIF did not differ from their typically developing classmates in terms of school motivation, anxiety, locus of control, or social adjustment, despite their lower academic performance. According to teachers, students with BIF had significantly lower school motivation and delayed socialization. For students with BIF but not for the comparison group, a negative correlation was found between mothers’ tendency to dominate over their child and students’ locus of control and school motivation. Conclusions Children with BIF are especially sensitive to the quality of mothers’ parenting style, which can have an adverse effect on their school adjustment.

  2. Brief Symptom Inventory symptom profiles of outpatients with borderline intellectual functioning and major depressive disorder or posttraumatic stress disorder: Comparison with patients from regular mental health care and patients with Mild Intellectual Disabilities.

    Science.gov (United States)

    Wieland, Jannelien; Zitman, Frans G

    2016-01-01

    In most countries, people with borderline intellectual functioning (BIF) are not considered a separate group in mental health care. There is little to no research on the impact of BIF on the presentation, nature and severity of mental health problems. The aim of the present exploratory study was to compare, in a naturalistic setting of patients referred to secondary care, symptom profiles of patients with BIF diagnosed with either major depressive disorder (MDD) or posttraumatic stress disorder (PTSD) to patients from regular mental health care (RMHC) and patients with Mild ID diagnosed with the same disorders. We used a cohort of adolescent and adult outpatients (aged 16-88) with or without BIF diagnosed with a primary diagnosis MDD or PTSD. Primary outcome was the nature and severity of psychopathological symptoms assessed at baseline using the Brief Symptom Inventory. All outcomes were adjusted for gender and age. Results showed that BIF patients with a primary diagnosis MDD reported less severe symptoms on BSI Total and the subscales Depression, Obsession-Compulsion and Psychoticism than patients from regular mental health care (RMHC). There were no statistically significant differences in reported symptom severity on BSI Total and the different BSI subscales between BIF patients with PTSD and either patients from RMHC or patients with Mild ID. Patients Mild ID, did report significantly less severe symptoms on the subscale Depression and on the subscale Psychoticism than patients from RMHC. Since there were no other published studies into symptom profiles in patients with BIF compared to either patients with higher or lower levels of cognitive functioning, the study was mainly exploratory in nature, providing direction for future research. Results indicate that symptom profiles did not widely differ, but that there might be some characteristics unique to patients BIF separating them as a group from both patients from RMHC and patients with Mild ID. Copyright

  3. Investigation of distinctive characteristics of children with specific learning disorder and borderline intellectual functioning

    Directory of Open Access Journals (Sweden)

    Selcuk Ozkan

    Full Text Available Abstract Background Borderline intelligence function (BIF and specific learning disorder (SLD are common diagnoses in children who are brought up for learning problems and school failure. Objective The aim of our study was to determine whether there were distinctive aspects of cognitive testing routinely used in evaluating SLD and BIF and investigate emotion regulation skills and minor neurologic symptoms. Method Sixty children (30 SLD and 30 BIF who are currently attending primary school are selected for study. Visual Aural Digit Span Test – Form B, Gessel Figure Drawing Test, Bender Gestalt Visual Motor Perception Test, WISC-R, Emotion Regulation Scale (ERS and Neurological Evaluation Scale (NES was administered. Results There was no statistically significant difference between groups in cognitive tests. The emotional regulation ability measured by the emotional regulation subscale was better in the SLD group than the BIF group (p = 0.014. In the NES, sensory integration (p = 0.008, motor coordination (p = 0.047 and other (p < 0.001 subscales showed higher scores in the BIF group. Discussion It has been shown that cognitive tests don’t have distinguishing features in the evaluation of SLD and BIF. Emotion regulation subscale score of ERS and sensory integration, motor coordination, and total scores of NES can be used in both discrimination of groups.

  4. Social competence in children with borderline intellectual functioning: delayed development of Theory of Mind across all complexity levels

    Directory of Open Access Journals (Sweden)

    Gisella Baglio

    2016-10-01

    Full Text Available Borderline intellectual functioning (BIF is characterized by heterogeneous cognitive difficulties, with an Intelligence Quotient (IQ between 70-85 points, and a failure to meet the developmental and sociocultural standards for personal independence and social responsibility required in daily life. The fact that people with BIF still remain a marginal clinical category, with no ad hoc diagnostic and therapeutic approaches, has stimulated the present research. Our goal was to study BIF children investigating the development of Theory of Mind (ToM as a pillar of social competence. Children with BIF (N=28, 16 male/12 female, mean age 9.46 ± 1.26 years and children with typical development (TD (N=31, 17 male/14 female; mean age 8.94 years ± 0.99 underwent a neurocognitive assessment and a ToM assessment. Children with BIF showed a significant lower performance across all the levels of ToM development investigated compared to the control group, and a correlation between executive functions and the advanced levels of ToM reasoning. These results constitute a first step in the direction of defining the clinical profile of BIF concerning ToM development, opening the way to future interventions in order to support the developmental evolution of this people in an adaptive direction.

  5. Using Digital Acoustic Recording Tags to Detect Marine Mammals on Navy Ranges and Study their Responses to Naval Sonar

    Science.gov (United States)

    2011-02-01

    densirostris) off the coast of El Hierro in the Canary Islands. A tag was deployed with relative ease on an adult beaked whale which proceeded to carry it for...located off-shore of El Hierro by chance. On examination, we found that water ingress had again caused failure of the recording circuit early in the

  6. Reliability-Limiting Defects in GaN/AlGaN High Electron Mobility Transistors

    Science.gov (United States)

    2011-12-01

    GaN grown by plasma-assisted molecular beam epitaxy”, Appl. Phys. Lett., vol. 77, no. 18, pp. 2885- 2887, 2000. [24] A. Hierro , A. R. Arehart, B...defects and impurities: Applications to III-nitrides”, J. Appl. Phys., vol. 95, pp.3851-3879, 2004. [43] A. Hierro , S. A. Ringel, M. Hansen, J. S

  7. Updating the Geologic Barcodes for South China: Discovery of Late Archean Banded Iron Formations in the Yangtze Craton.

    Science.gov (United States)

    Ye, Hui; Wu, Chang-Zhi; Yang, Tao; Santosh, M; Yao, Xi-Zhu; Gao, Bing-Fei; Wang, Xiao-Lei; Li, Weiqiang

    2017-11-08

    Banded iron formations (BIFs) in Archean cratons provide important "geologic barcodes" for the global correlation of Precambrian sedimentary records. Here we report the first finding of late Archean BIFs from the Yangtze Craton, one of largest Precambrian blocks in East Asia with an evolutionary history of over 3.3 Ga. The Yingshan iron deposit at the northeastern margin of the Yangtze Craton, displays typical features of BIF, including: (i) alternating Si-rich and Fe-rich bands at sub-mm to meter scales; (ii) high SiO 2  + Fe 2 O 3total contents (average 90.6 wt.%) and Fe/Ti ratios (average 489); (iii) relative enrichment of heavy rare earth elements and positive Eu anomalies (average 1.42); (iv) and sedimentary Fe isotope compositions (δ 56 Fe IRMM-014 as low as -0.36‰). The depositional age of the BIF is constrained at ~2464 ± 24 Ma based on U-Pb dating of zircon grains from a migmatite sample of a volcanic protolith that conformably overlied the Yingshan BIF. The BIF was intruded by Neoproterozoic (805.9 ± 4.7 Ma) granitoids that are unique in the Yangtze Craton but absent in the North China Craton to the north. The discovery of the Yingshan BIF provides new constraints for the tectonic evolution of the Yangtze Craton and has important implications in the reconstruction of Pre-Nuna/Columbia supercontinent configurations.

  8. Social Competence in Children with Borderline Intellectual Functioning: Delayed Development of Theory of Mind Across All Complexity Levels

    Science.gov (United States)

    Baglio, Gisella; Blasi, Valeria; Sangiuliano Intra, Francesca; Castelli, Ilaria; Massaro, Davide; Baglio, Francesca; Valle, Annalisa; Zanette, Michela; Marchetti, Antonella

    2016-01-01

    Borderline intellectual functioning (BIF) is characterized by heterogeneous cognitive difficulties, with an intelligence quotient (IQ) between 70 and 85 points, and a failure to meet the developmental and sociocultural standards for personal independence and social responsibility required in daily life. The fact that this population still remain a marginal clinical category, with no ad hoc diagnostic and therapeutic approaches, has stimulated the present research. Our goal was to study children with BIF investigating the development of Theory of Mind (ToM) as a pillar of social competence. Children with BIF (N = 28, 16 male/12 female, and mean age 9.46 ± 1.26 years) and children with typical development (TD; N = 31, 17 male/14 female; mean age 8.94 years ± 0.99) underwent a neurocognitive assessment and a ToM assessment. Children with BIF showed a significant lower performance across all the levels of ToM development investigated compared to the control group, and a correlation between executive functions and the advanced levels of ToM reasoning. These results constitute a first step in the direction of defining the clinical profile of children with BIF concerning ToM development, opening the way to future interventions in order to support the developmental evolution of this population in an adaptive direction. PMID:27818637

  9. Social Competence in Children with Borderline Intellectual Functioning: Delayed Development of Theory of Mind Across All Complexity Levels.

    Science.gov (United States)

    Baglio, Gisella; Blasi, Valeria; Sangiuliano Intra, Francesca; Castelli, Ilaria; Massaro, Davide; Baglio, Francesca; Valle, Annalisa; Zanette, Michela; Marchetti, Antonella

    2016-01-01

    Borderline intellectual functioning (BIF) is characterized by heterogeneous cognitive difficulties, with an intelligence quotient (IQ) between 70 and 85 points, and a failure to meet the developmental and sociocultural standards for personal independence and social responsibility required in daily life. The fact that this population still remain a marginal clinical category, with no ad hoc diagnostic and therapeutic approaches, has stimulated the present research. Our goal was to study children with BIF investigating the development of Theory of Mind (ToM) as a pillar of social competence. Children with BIF ( N = 28, 16 male/12 female, and mean age 9.46 ± 1.26 years) and children with typical development (TD; N = 31, 17 male/14 female; mean age 8.94 years ± 0.99) underwent a neurocognitive assessment and a ToM assessment. Children with BIF showed a significant lower performance across all the levels of ToM development investigated compared to the control group, and a correlation between executive functions and the advanced levels of ToM reasoning. These results constitute a first step in the direction of defining the clinical profile of children with BIF concerning ToM development, opening the way to future interventions in order to support the developmental evolution of this population in an adaptive direction.

  10. Necesidades de investigación para el diagnóstico de anemia en poblaciones de altura

    Directory of Open Access Journals (Sweden)

    Gustavo F. Gonzales

    Full Text Available RESUMEN Tanto la deficiencia como la sobrecarga de hierro son situaciones que ponen en riesgo la salud y la vida de las personas, por lo que es importante mantener su homeostasis. Como la hemoglobina contiene 70% del hierro del organismo, la OMS recomienda su medición para determinar la prevalencia de anemia por deficiencia de hierro (ID, a pesar que ellos mismos reconocen que la anemia no es específica de ID. Como la hemoglobina aumenta con la altitud de residencia, la OMS recomienda corregir el punto de corte para definir anemia en la altura. Una objeción a esta corrección es que el aumento de la hemoglobina en la altura no es universal ni aumenta de manera lineal. Además, las poblaciones de mayor antigüedad generacional tienen menos hemoglobina que las más recientes. En infantes, niños, gestantes y adultos, la prevalencia de anemia usando hemoglobina corregida es 3-5 veces mayor que usando marcadores del estatus de hierro. Los programas estatales buscan combatir la anemia mediante la suplementación de hierro; no obstante, resultan ineficaces, especialmente en las poblaciones de altura. Entonces, ¿hay deficiencia de hierro en la altura? Los niveles de hepcidina sérica, hormona que regula la disponibilidad de hierro, son similares a los de nivel del mar indicando que en la altura no hay deficiencia de hierro. Un problema adicional al corregir la hemoglobina por la altura, es que las prevalencias de eritrocitosis disminuyen. En conclusión, la corrección del punto de corte de la hemoglobina en la altura para determinar deficiencia de hierro es inadecuada.

  11. Necesidades de investigación para el diagnóstico de anemia en poblaciones de altura

    OpenAIRE

    Gonzales, Gustavo F.; Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia. Lima, Perú Instituto de Investigaciones de la Altura, Universidad Peruana Cayetano Heredia. Lima, Perú Doctor en Ciencias; doctor en Medicina; Fano, Diego; Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia. Lima, Perú. licenciado; Vásquez Velásquez, Cinthya; Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia. Lima, Perú. licenciado

    2017-01-01

    Tanto la deficiencia como la sobrecarga de hierro son situaciones que ponen en riesgo la salud y la vida de las personas, por lo que es importante mantener su homeostasis. Como la hemoglobina contiene 70% del hierro del organismo, la OMS recomienda su medición para determinar la prevalencia de anemia por deficiencia de hierro (ID), a pesar que ellos mismos reconocen que la anemia no es específica de ID. Como la hemoglobina aumenta con la altitud de residencia, la OMS recomienda corregir el pu...

  12. Petrology and geochemistry of the ~2.9 Ga Itilliarsuk banded iron formation and associated supracrustal rocks, West Greenland

    DEFF Research Database (Denmark)

    Haugaard, Rasmus; Frei, Robert; Stendal, Henrik

    2013-01-01

    unconformably on a basement of tonalite–trondhjemite–granodiorite (TTG) lithologies. Felsic metagreywackes, meta-semipelites and thinly bedded ferruginous shales were identified intercalated with the Itilliarsuk BIF. Other associated rocks include metapelites, acidic metavolcanics and metagabbroic sills.......29. The associated supracrustal rocks in the study area have significantly higher, positive ɛNd(i) values. The 143Nd/144Nd in the Itilliarsuk BIF, therefore, contrasts world BIFs by exhibiting radiogenic, positive ɛNd(i) values in shallow seawaters where the REY's were controlled by a local, depleted continental...... crust, whereas the negative ɛNd(i) values found in the iron-rich layers suggest that the submarine hydrothermal source was influenced by an enriched mantle, possibly an older subcontinental lithospheric segment. The felsic metagreywackes are immature, first-cycle (SiO2/Al2O3 ∼ 4.4, [La/Yb >> 1]CHON...

  13. Towards a framework for psychological resilience in children and adolescents with Borderline Intellectual Functioning

    Directory of Open Access Journals (Sweden)

    Jankowska Anna

    2016-09-01

    Full Text Available Psychological well-being is one of the greatest concerns in children and adolescents with Borderline Intellectual Functioning (BIF. Those youths are frequently exposed to stress and social inequality, and they are particularly prone to developing mental health issues which persist through adolescence and into adult life. The purpose of this article is to introduce a framework for promoting psychological resilience in children and adolescents with BIF. Three interrelated and complementary factors require professional attention and efforts to improve resilience in children with borderline intelligence: a protecting a child’s self-worth, b generating sources of social support, c training of adaptive coping skills. The significance of early diagnosis and continuous monitoring of a child’s development is also discussed. Children with BIF should be provided with internal (self-worth, coping skills and external (social support resources to enhance their resilience and ability to confront adversities, and to reduce the risk of mental health issues.

  14. Caracterização de biocerâmicos à base de hidroxiapatite

    OpenAIRE

    Monteiro, Telmo Filipe

    2015-01-01

    Esta dissertação tem por objetivo estudar e caracterizar materiais biocerâmicos à base de fosfato de cálcio. O material estudado foi a hidroxiapatite sintetizada pelo método de precipitação aquosa em meio aquoso, assim como os pós bifásicos. Foram utilizados 3 tipos de pós, hidroxiapatite com um grau de pureza elevado (Ca10(PO4)6(OH2)) (HAP), pó bifásico (com as fases Ca10(PO4)6(OH)2 e β-TCP) (HTCP) e pó bifásico com magnésio (Ca10(PO4)6(OH)2 + β-TCP + Mg) (HTCP-Mg). Post...

  15. Abnormal development of sensory-motor, visual temporal and parahippocampal cortex in children with learning disabilities and borderline intellectual functioning

    Directory of Open Access Journals (Sweden)

    Francesca eBaglio

    2014-10-01

    Full Text Available Borderline intellectual functioning (BIF is a condition characterized by an intelligence quotient (IQ between 70 and 85. BIF children present with cognitive, motor, social and adaptive limitations that result in learning disabilities and are more likely to develop psychiatric disorders later in life. Aim of this study was to investigate brain morphometry and its relation to IQ level in borderline intellectual functioning children.Thirteen children with BIF and 14 age- and sex-matched typically developing children were enrolled. All children underwent a full IQ assessment (WISC-III scale and a Magnetic Resonance (MR examination including conventional sequences to assess brain structural abnormalities and high resolution 3D images for voxel based morphometry (VBM analysis. To investigate to what extent the group influenced gray matter volumes, both univariate and multivariate generalized linear model analysis of variance were used, and the varimax factor analysis was used to explore variable correlations and clusters among subjects. Results showed that BIF children, compared to controls have increased regional gray matter volume in bilateral sensori-motor and right posterior temporal cortices and decreased gray matter volume in right parahippocampal gyrus. Gray matter volumes were highly correlated with IQ indices.Our is a case study of a group of BIF children showing that BIF is associated with abnormal cortical development in brain areas that have a pivotal role in motor, learning and behavioral processes. Our findings, although allowing for little generalization to general population, contributes to the very limited knowledge in this field. Future longitudinal MR studies will be useful in verifying whether cortical features can be modified over time even in association with rehabilitative intervention.

  16. Gender, parental education, and experiences of bullying victimization by Australian adolescents with and without a disability.

    Science.gov (United States)

    Kavanagh, A; Priest, N; Emerson, E; Milner, A; King, T

    2018-03-01

    This study sought to compare the prevalence of bullying victimization between adolescents with and without a disability and between adolescents with and without borderline intellectual functioning or intellectual disability (BIF/ID). We also sought to assess whether the relationships between either disability or BIF/ID and bullying victimization vary by gender and parental education. The sample included 3,956 12- to 13-year-old adolescents who participated in Wave 5 of the Longitudinal Study of Australian Children. Three indicators of bullying were used: physical bullying victimization, social bullying victimization, and "any bullying victimization." We used Poisson regression to obtain the prevalence risk ratios (PRR) of bullying by disability status adjusting for potential confounders. In adjusted models, we found evidence that social bullying victimization was more prevalent among adolescents with a disability than those without a disability (PRR 1.29, 95% confidence interval [CI] 1.06-1.42) and between adolescents with BIF/ID than those without (PRR 1.24, 95% CI 1.07-1.44). Adolescents with BIF/ID were also more likely to experience "any bullying victimization"(PRR 1.10, 95% CI 1.00-1.22). Having a disability and living in a family with low parental education were associated with an elevated risk of social bullying victimization BIF/ID. Adolescents with disabilities and BIF/ID are at elevated risk of social bullying victimization. School-based antibullying initiatives should concentrate on enhancing the inclusion of adolescents with disabilities, with an emphasis on adolescents from disadvantaged backgrounds. © 2018 John Wiley & Sons Ltd.

  17. Mesoarchean Banded Iron Formation sequences in Dixon Island-Cleaverville Formation, Pilbara Australia: Oxygenic signal from DXCL project

    Science.gov (United States)

    Kiyokawa, S.; Ito, T.; Ikehara, M.; Yamaguchi, K. E.; Naraoka, H.; Onoue, T.; Horie, K.; Sakamoto, R.; Aihara, Y.; Miki, T.

    2013-12-01

    The 3.2-3.1 Ga Dixon island-Cleaverville formations are well-preserved Banded Iron Formation (BIF) within hydrothermal oceanic sequence at oceanic island arc setting (Kiyokawa et al., 2002, 2006, 2012). The stratigraphy of the Dixon Island (3195+15Ma) -Cleaverville (3108+13Ma) formations shows the well preserved environmental condition at the Mesoarchean ocean floor. The stratigraphy of these formations are formed about volcano-sedimentary sequences with hydrothermal chert, black shale and banded iron formation to the top. Based on the scientific drilling of DXCL project at 2007 and 2011, detail lithology between BIF sequence was clearly understood. Four drilling holes had been done at coastal sites; the Dixon Island Formation is DX site (100m) and the Cleaverville Formation is CL2 (40m), CL1 (60m) and CL3 (200m) sites and from stratigraphic bottom to top. Coarsening and thickening upward black shale-BIF sequences are well preserved of the stratigraphy form the core samples. The Dixon Island Formation consists komatiite-rhyolite sequences with many hydrothermal veins and very fine laminated cherty rocks above them. The Cleaverville Formation contains black shale, fragments-bearing pyroclastic beds, white chert, greenish shale and BIF. The CL3 core, which drilled through BIF, shows siderite-chert beds above black shale identified before magnetite lamination bed. U-Pb SHRIMP data of the tuff in lower Dixon Island Formation is 3195+15 Ma and the pyroclastic sequence below the Cleaverville BIF is 3108+13 Ma. Sedimentation rate of these sequence is 2-8 cm/ 1000year. The hole section of the organic carbon rich black shales below BIF are similar amount of organic content and 13C isotope (around -30per mill). There are very weak sulfur MIF signal (less 0.2%) in these black shale sequence. Our result show that thick organic rich sediments may be triggered to form iron rich siderite and magnetite iron beds. The stratigraphy in this sequence quite resemble to other Iron

  18. Rare earth elements in the banded iron formation of the Griqualand West sequence, northern Cape Province, South Africa

    International Nuclear Information System (INIS)

    Horstmann, U.E.; Haelbich, I.W.; Cornell, D.H.

    1990-01-01

    The Proterozoic banded iron-formations (BIF) of the Griqualand West sequence of the Transvaal Supergroup in the northern Cape Province of South Africa have been investigated for their rare earth elements (REE) contents. Twenty three REE analyses were completed using an ICP-AES method. Despite diagenetic and metamorphic processes, it can be concluded from the so far available REE data that the conspicuous differences in REE patterns to those reported from elsewhere indicate the BIF of the Transvaal Supergroup to have originated in relative restricted parts or basins of the Precambrian ocean. 7 refs., 1 fig

  19. Iron oxides, divalent cations, silica, and the early earth phosphorus crisis

    DEFF Research Database (Denmark)

    Jones, C.; Nomosatryo, S.; Crowe, S.A.

    2015-01-01

    As a nutrient required for growth, phosphorus regulates the activity of life in the oceans. Iron oxides sorb phosphorus from seawater, and through the Archean and early Proterozoic Eons, massive quantities of iron oxides precipitated from the oceans, producing a record of seawater chemistry...... that is preserved as banded iron formations (BIFs) today. Here we show that Ca2+, Mg2+, and silica in seawater control phosphorus sorption onto iron oxides, influencing the record of seawater phosphorus preserved in BIFs. Using a model for seawater cation chemistry through time, combined with the phosphorus...... waters shifted from phosphorus to iron limiting....

  20. Comment on “Identification of the subsurface sulfide bodies responsible for acidity in Río Tinto source water, Spain” by Gómez-Ortiz et al. (Earth Planet. Sci. Lett. 391 (2014) 36-41)

    Science.gov (United States)

    Olías, Manuel; Nieto, José Miguel

    2014-10-01

    The source of the Río Tinto (SW Spain) is currently located close to the Peña de Hierro mine, where it receives the first acidic waters. A few kilometers south, the river crosses the Río Tinto mines, a supergiant massive sulfide deposit that is much more important than those of Peña de Hierro, and the acid pollutant contributions to the river increase by orders of magnitude.

  1. Alfileres de cabeza trapezoidal y hebillas anulares en omega de los "castros de Lastra" (Caranca-Álava

    Directory of Open Access Journals (Sweden)

    Francisca SÁENZ DE URTURI

    2009-10-01

    Full Text Available Las excavaciones que actualmente se llevan a cabo en el yacimiento de Los Castros de Lastra, han proporcionado abundantes objetos metálicos, siendo algunos de ellos de gran interés para el conocimiento de la Edad del Hierro, especialmente de la Segunda Edad del Hierro. Este es el caso de los alfileres de cabeza trapezoidal, de bronce, con cuatro ejemplares, y de los que no hemos encontrado paralelos cercanos hasta el momento.

  2. Efetividade da suplementação diária ou semanal com ferro na prevenção da anemia em lactentes Efectividad en el suplemento diario o semanal de hierro en la prevención de anemia en lactantes Effectiveness of daily and weekly iron supplementation in the prevention of anemia in infants

    Directory of Open Access Journals (Sweden)

    Elyne Montenegro Engstrom

    2008-10-01

    Full Text Available OBJETIVO: Avaliar a efetividade da suplementação universal profilática com sulfato ferroso, em administração diária ou semanal, na prevenção da anemia em lactentes. MÉTODOS: Ensaio de campo randomizado com crianças de seis a 12 meses de idade, atendidas em unidades básicas de saúde do município do Rio de Janeiro, em 2004-2005. Foram formadas três coortes concorrentes com suplementação universal com sulfato ferroso com grupos: diário (n=150; 12,5mgFe/dia, semanal (n=147; 25mgFe/semana e controle (n=94. A intervenção durou 24 semanas e foi acompanhada por ações educativas promotoras de adesão. A concentração de hemoglobina sérica foi analisada segundo sua distribuição, média e prevalência de anemia (HbOBJETIVO: Evaluar la efectividad del suplemento universal profiláctico con sulfato ferroso, en administración diaria o semanal, en la prevención de la anemia en lactantes. MÉTODOS: Se realizo un ensayo de campo aleatorio con niños de seis a 12 meses de edad, atendidos en unidades básicas de salud del municipio de Río de Janeiro (Sureste de Brasil, en 2004-2005. Se formaron tres cohortes coincidentes con suplemento universal con sulfato ferroso con grupos: diario (n=150; 12,5mgFe/dia, semanal (n=147; 25mgFe/semana y control (n=94. La intervención duró 24 semanas y fue acompañada por acciones educativas promotoras de adhesión. La concentración de hemoglobina sérica fue analizada de acuerdo a su distribución, promedio y prevalencia de anemia (HbOBJECTIVE: To evaluate the effectiveness of universal prophylactic targeting with iron sulfate on daily or weekly basis in the prevention of anemia in infants. METHODS: Randomized clinical field trial with children between ages six and 12 months seen at primary health care units in the municipality of Rio de Janeiro, Brazil, between 2004 and 2005. Three concurrent cohorts were compared: daily group (n=150; 12.5mg Fe/day; weekly group (n=147; 25mg Fe/week and control group. The intervention consisted of universal supplementation with iron sulfate for 24 weeks, combined with educational adherence-promoting measures. Outcome: mean serum hemoglobin concentration, distribution and prevalence of anemia (Hb<110.0 g/l at age 12 months. Effectiveness was evaluated considering both intent to treat and adherence to protocol, using multiple regression analysis (linear and Poisson. RESULTS: Groups were homogeneous in terms of descriptive variables. The intervention was implemented successfully, with high adhesion to protocol in both groups, and no statistical difference between them. After adjustment, only the daily regimen showed a protective effect. Adherence analysis demonstrated an evident dose-response effect on mean Hb and prevalence of anemia only for the daily regimen. No protective effect was detected for the weekly regimen. CONCLUSIONS: Universal supplementation with iron sulfate from six to 12 months of age was effective in increasing serum Hb and decreasing risk of anemia only when administered on a daily basis.

  3. Eutrophication and its influence in quality of water II. Experimental Application to dam ''Isla de Hierro''(Madrid). La eutrofizacion y su incidencia en la calidad de las aguas subterraneas. II: Aplicacion experimental a la balsa ''Isla del Herrero'' (Madrid)

    Energy Technology Data Exchange (ETDEWEB)

    Gomez Martos, M.; Buyo Hernandez, F.

    1993-01-01

    After selecting the tailing dam that presents eutrophication processes using statistical methods, performing an EIA and carrying out an hydrogeological study of the area, sampling and physical, chemical and biological analysis of dam water, sediments and groundwater in different seasons were accomplished. Based on the results and according to the Discriminant and Factorial Analysis and Canonical Correlation applied, was established the eutrophication model which relates the variation of chlorophyll-a with nitrate, orthophosphate, ammonium and manganese (iron contents). Likewise, the role and importance of phytoplankton as control and reduction factor of nutrients was confirmed.

  4. Contenido pseudototal de Cobre, Cinc, Hierro y Manganeso como estimador del fondo geoquímico en suelos de la Llanura Chaco-Pampeana de Córdoba, Argentina Pseudototal Copper, Zinc, Iron and Manganese content in soils for assessing the geochemical background of the Chaco-Pampean Plain of Cordoba, Argentina

    Directory of Open Access Journals (Sweden)

    Eduardo V Buffa

    2009-12-01

    Full Text Available RESUMEN El contenido total de un nutriente en el suelo es importante para conocer la fertilidad potencial para la nutrición vegetal y constituye una información básica en estudios ambientales y edafogenéticos. El objetivo de este trabajo fue determinar el contenido «pseudototal» de Cu, Zn, Fe y Mn en suelos de la llanura chaco-pampeana de Córdoba, Argentina, mediante una extracción multielemental con HNO3 4 M, pudiendo ser utilizado como aproximación del fondo geoquímico y de línea geoquímica de referencia según se analicen los datos de muestras superficiales y subsuperficiales o superficiales respectivamente. Estos datos se relacionaron con atributos edáficos de importancia agronómica: carbono orgánico, acidez, salinidad y carbonatos. Los contenidos promedios obtenidos fueron: 11,3 a 19,2 mg Cu kg-¹; 29,4 a 61,5 mg Zn kg-¹; 285 a 626 mg Mn kg-¹ y 9 a 19,9 g Fe kg-¹ en la profundidad 0-60 cm de los suelos de la llanura chaco-pampeana de Córdoba (Argentina y están dentro del rango de valores de referencia a escala mundial, con los valores menores en los suelos de textura más gruesa. Para el suelo superficial (0-20 cm, los valores promedio fueron de 15,7 a 17,7 mg Cu kg-¹, 53,5 a 56,5 mg Zn kg-¹, 548 a 564 mg Mn kg-¹ y 15,8 a 16,¹ g Fe kg-¹ en suelos loéssicos y limo-loéssicos y de 11,9 mg Cu kg-¹ (DSt: 2,8; 34,6 mg Zn kg-¹ (DSt: 8; 309 mg Mn kg-¹ (DSt: 98 y 11,9 g Fe kg-¹ (DSt: 3,2 en suelos franco-arenosos. Las diferencias texturales entre las regiones de suelos loéssicos y arenosos se tradujeron en valores de fondo geoquímico diferentes para los cuatro elementos estudiados, con menores contenidos en los suelos de textura más gruesa. El análisis de regresión múltiple incluyó a Fe y Mn como las principales variables explicativas de los cuatro elementos en todas las profundidades, relacionado con la alta afinidad existente entre los metales de transición, con tendencia a coprecipitar como óxidos de baja cristalinidad. El carbono orgánico en superficie como segunda variable en la mayoría de los modelos para los cuatro elementos confirma la importancia de la materia orgánica como fuente de estos microelementos.Data on the total nutrient content of soils is essential for assessing potential fertility and is fundamental to environmental and edaphogenetic studies. The aim of this paper was to measure Cu, Zn, Fe y Mn in soils of the Chaco Pampean Plain in Argentina using the simultaneous acid nitric (HNO3 4 M extraction procedure (called pseudototal to infer geochemical background and geochemical baseline data by analysing surface and subsurface samples. The results can be related with other edaphic features such as organic carbon, acidity, salinity and carbonates. Average values of 11.3 to 19.2 mg Cu kg-¹, 29.4 to 61.5 mg Zn kg-¹, 285 to 626 mg Mn kg-¹ g-¹ and 9 to 19.9 g Fe kg-¹ were found at a soil depth of 0-60 cm, falling within the range reported in worldwide literature. The lowest values were found in sandy soils. The values at a soil depth of 0-20 cm were 17 mg Cu kg-1, 55 mg Zn kg-¹, 562 mg Mn kg-¹ and 16 g Fe kg-¹ in loessic and loam loessic soils and 12 Cu kg-¹, 36 mg Zn kg-¹, 347 mg Mn kg-¹ and 11 g Fe kg-¹in loam sandy soils. The textural difference between loessic and sandy soils reflects different background values for the four elements studied, the lowest values corresponding to sandy soils. Multiple regression analysis included Fe and Mn as the main variables to explain the amounts found for each of the four elements at each depth which is related to the high affinity between transition metals and their tendency to co-precipitate as low cristallinity oxides.The second variable in most of the models for the studied elements was organic carbon, confirming the importance of organic matter as a primary source of these micronutrients.

  5. La capacidad prospectiva y de visualización del escáner láser 3D aplicado al plan de conservación preventiva del conjunto cerámico, piedra y hierro de Antoni Gaudí y Josep María Jujol en la catedral gótica de Mallorca

    Directory of Open Access Journals (Sweden)

    Juan Antonio Ruiz

    2012-05-01

    Full Text Available In this work it is presented the prospective and visualization efficiency of the 3D laser scanner as a tool applied to the elaboration of a preventive conservation plan of the ceramic done by Antoni Gaudí and Josep Maria Jujol in the gothic cathedral of Mallorca .The usage of this technique has enabled its investigation regarding digital information storage and metrology of the whole surface and plastic elements in it. This ways it is determined the creation of a multidisciplinary and interactive database with documental, technical and prescriptive content in order to compose the preventive conservation plan.

  6. NIVELES SÉRICOS DE MAGNESIO, HIERRO Y COBRE EN POBLACIÓN DE ADULTOS DE CIUDAD BOLÍVAR, ESTADO BOLÍVAR, VENEZUELA I SERUM LEVELS OF MAGNESIUM , IRON AND COPPER IN ADULT POPULATION FROM CIUDAD BOLIVAR, BOLIVAR STATE, VENEZUELA

    Directory of Open Access Journals (Sweden)

    María Caride

    2014-02-01

    Full Text Available Determination of bioelements concentrations in serum are considered very important, since they allow to establish reference levels that can be used to detect essential elements deficiency or poisoning by their excess. The aim of this study was to identify the serum levels of magnesium, iron and copper in a population of apparently healthy adults, residents of an urban area of Ciudad Bolivar, Bolivar State, The sample consisted of 57 individuals (28 men and 29 women that were not occupationally exposed residents in Ciudad Bolivar, aged between 25 and 60 years. Bioelements were determined by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES after acid digestion of serum samples. The average concentration values (± SD of magnesium, iron and copper obtained were, respectively, 22 ± 3 mg.L-1, 1.1 ± 0.2 mg.L-1 y 1.0 ± 0.2 mg.L-1. Regarding the studied bioelement levels, only magnesium levels of men were significantly higher (p < 0.05 than the levels of women. The mean concentrations of bioelements were within ranges of reference values reported in the literature for healthy people, but significantly different (p < 0,05 to those from Merida, another region from Venezuela, and a possible consequence of changes in eating habits and environment conditions among these two Venezuelan regions.

  7. Study of the Cd (II) removal in the presence of methyl orange with a natural zeolite conditioned with iron nanoparticles; Estudio de la remocion de Cd(II) en presencia de naranja de metilo con una zeolita natural acondicionada con nanoparticulas de hierro

    Energy Technology Data Exchange (ETDEWEB)

    Xingu C, E. G.

    2015-07-01

    This work presents a study on the removal of cadmium and/or methyl-orange dye in aqueous solution, using natural zeolite clinoptilolite, as sodium homo-ionized and impregnated with iron nanoparticles. Iron nanoparticles were synthesized in the presence of the zeolite by chemical reduction. The evaluation of the removal ability was performed in a monocomponent (cadmium or methyl-orange dye) system by varying the contact time and its initial concentration. Removal capacity in a bi-component (cadmium and methyl orange) system was also studied while varying their concentrations. The characterization of the zeolites, before and after the sorption process, was carried out using several analytical techniques. The characteristics of zeolite clinoptilolite and iron particles were observed by scanning electron microscopy. The iron particles showed diameter sizes between 60 and 200 nm, localized on the surface of the zeolite. By IR spectroscopy no structural changes were detected for any of the treatments made to the zeolitic materials. By X-ray diffraction the clinoptilolite crystalline phase was mainly identified, however, it failed to detect any phase of iron in the zeolite impregnated with iron nanoparticles. Moessbauer spectroscopy indeed detected the impregnated iron phase as iron borides. The homo-ionized and iron nanoparticles impregnated zeolite showed no change in the specific surface area, or the isoelectric point, their values were 22.3 m{sup 2}/g and ph 9.8, respectively. However, whereas the active site density for the homo-ionized zeolite was 2.87 sites/nm{sup 2}, for iron nanoparticles impregnated zeolite was 20.32 sites/nm{sup 2}. As a result of the analysis of the isotherms of cadmium, the maximum sorption capacity of the homo-ionized zeolite was 35.03 mg/g and for the iron nanoparticles impregnated zeolite was 36.43 mg/g. These maximum sorption capacities represent up to 85% of removed cadmium from concentrations of 50 to 600 mg/L. For the removal of methyl orange dye case, the homo-ionized zeolite did not remove any; however, the iron nanoparticles impregnated zeolite its maximum removal capacity was 79.8 mg/g. In the two-component system the removal capacity could not be assessed due to the presence precipitates formed between the methyl-orange dye and cadmium solutions. (Author)

  8. Evaluación de la reactividad de sulfuros de hierro y residuos mineros: una metodología basada en la aplicación de la voltamperometría cíclica Evaluation of the reactivity of iron sulfides and mining wastes: methodology based on cyclic voltammetry

    Directory of Open Access Journals (Sweden)

    Roel Cruz y Marcos Monroy

    2006-06-01

    Full Text Available The mining industry around the world produces an important amount of wastes, which by their high toxic metal and iron sulfide content present a serious environmental problem. Iron sulfide oxidation under weathering conditions provokes the main environmental problem of the mining industry, the generation of Acid Rock Drainage (ARD. Up to now the prediction methodologies do not allow the study of important factors that influence the generation of ARD, producing in some cases erroneous or uncertain conclusions. This paper shows the utilization of cyclic voltammetry using carbon paste electrodes (CPE-Mineral as an alternative tool in the study of the oxidation capacity of iron sulfides and mining wastes. This electrochemical technique constitutes a novel methodology to establish and understand the factors involved during generation of ARD. Results of several studies including selected sulfide samples and sulfide mining wastes have been described in order to show the capacity of this methodology as a complementary tool in the prediction of the generation of ARD.

  9. Synthesis and characterization of iron (II and III) phosphates by X-ray diffraction and Scanning Electron Microscopy of high vacuum; Sintesis y caracterizacion de fosfatos de hierro (II, III) por difraccion de rayos X y microscopia electronica de barrido de alto vacio

    Energy Technology Data Exchange (ETDEWEB)

    Diaz F, J.C.; Solis M, L.; Garcia R, G.; Romero G, E.T. [Departamento de Quimica, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2002-07-01

    The XRD and Sem techniques for determining the mineralogical and structural composition of iron II and III phosphates have been used. The mineralogical and structural composition of the materials revealed that they are the ferrous phosphate and the ferric phosphate. The contribution of the synthesis and characterization of these phosphates is that they can be used as components in the geological barriers capable to avoiding the dispersion from the hazardous radioactive materials to the environment. (Author)

  10. Estudio mediante teoría de funcionales de la densidad de las propiedades electrónicas, estructurales y energéticas de complejos organometálicos de cúmulos de hierro con benceno en fase gaseosa : fen(c6h&)m, n<=7, m>=4 /

    OpenAIRE

    Valencia Quiroz, Israel

    2012-01-01

     tesis que para obtener el grado de Doctorado en Ciencias Químicas, presenta Israel Valencia Quiroz ; asesor Miguel Castro Martínez149 páginas : ilustracionesDoctorado en Ciencias Químicas UNAM, Facultad de Química, 2012

  11. Thermal stability of nano structured iron powder as a function of amount and nature of reinforcement (Nb or NbC); Estudio de la estabilidad termica de polvo de hierro nanoestructurado en funcion del tipo de refuerzo (Nb, NbC) y de su contenido

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes-Pacheco, L.; Campos, M.; Torralba, J. M.

    2011-07-01

    In structural steels, an effective strategy to succeed in increasing both strength and toughness is the grain refining, like in microalloyed steels. To delay or even inhibit the grain growth there are two basic mechanisms: particle pinning and solute drag. The effect of the presence of small particles of NbC to inhibit the austenitic grain growth is well known. However, it is not so clear which mechanism will be more effective to delay ferritic grain growth. In order to confirm it, nano structured iron powders reinforced with Nb and NbC have been prepared by mechanical alloying. The main objective of this work is, therefore, to study the thermal stability of the nano structured powder as a function of the reinforce type (elemental Nb or NbC) and its content. (Author) 19 refs.

  12. Author Details

    African Journals Online (AJOL)

    Ezema, FI. Vol 17 (2005): - Articles Optical characterization of chemical bath deposited bismuth sulphide (Bi2S4) thin films. Abstract · Vol 19 (2007): - Articles Optical Properties of Chemical Bath Deposited Bismuth Fluoride (Bif3) Thin Films Abstract. ISSN: 1015-079X. AJOL African Journals Online. HOW TO USE AJOL.

  13. 75 FR 69126 - Proposed Information Collection Request (ICR) for the Workforce Investment Act Random Assignment...

    Science.gov (United States)

    2010-11-10

    ... study, a consent form, a baseline information form (BIF), and a contact information form (CIF). WIA adult and dislocated worker applicants will be asked to sign a consent form to confirm that they have... be collected through cost collection forms and interviews with program staff during the second site...

  14. NCBI nr-aa BLAST: CBRC-CFAM-06-0026 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-CFAM-06-0026 ref|YP_953134.1| translation initiation factor IF-2 [Mycobacterium vanba...alenii PYR-1] gb|ABM13128.1| bacterial translation initiation factor 2 (bIF-2) [Mycobacterium vanbaalenii PYR-1] YP_953134.1 0.002 28% ...

  15. Controversial Pb-Pb and Sm-Nd isotope results in the early Archean Isua (West Greenland) oxide iron formation

    DEFF Research Database (Denmark)

    Frei, Robert; Rosing, Minik; Stecher, Ole

    1999-01-01

    Pb stepwise leaching (PbSL) determinations on two magnetite-enriched fractions of a BIF sample from the northeastern part of the Isua supracrustal belt (West Greenland) yield an isochron of 3691 ± 22 Ma (MSWD = 0.4). In combination with previously published geochronological constraints for a mini...

  16. Motor Performance of Children with Mild Intellectual Disability and Borderline Intellectual Functioning

    Science.gov (United States)

    Vuijk, P. J.; Hartman, E.; Scherder, E.; Visscher, C.

    2010-01-01

    Background: There is a relatively small body of research on the motor performance of children with mild intellectual disabilities (MID) and borderline intellectual functioning (BIF). Adequate levels of motor skills may contribute to lifelong enjoyment of physical activity, participation in sports and healthy lifestyles. The present study compares…

  17. Composite Gypsum Binders with Silica-containing Additives

    Science.gov (United States)

    Chernysheva, N. V.; Lesovik, V. S.; Drebezgova, M. Yu; Shatalova, S. V.; Alaskhanov, A. H.

    2018-03-01

    New types of fine mineral additives are proposed for designing water-resistant Composite Gypsum Binders (CGB); these additives significantly differ from traditional quartz feed: wastes from wet magnetic separation of Banded Iron Formation (BIF WMS waste), nanodispersed silica powder (NSP), chalk. Possibility of their combined use has been studied as well.

  18. Motor performance of children with mild intellectual disability and borderline intellectual functioning

    NARCIS (Netherlands)

    Vuijk, P. J.; Hartman, E.; Scherder, E.; Visscher, C.

    2010-01-01

    Background There is a relatively small body of research on the motor performance of children with mild intellectual disabilities (MID) and borderline intellectual functioning (BIF). Adequate levels of motor skills may contribute to lifelong enjoyment of physical activity, participation in sports and

  19. Decoupling of Neoarchean sulfur sources recorded in Algoma-type banded iron formation

    Science.gov (United States)

    Diekrup, David; Hannington, Mark D.; Strauss, Harald; Ginley, Stephen J.

    2018-05-01

    Neoarchean Algoma-type banded iron formations (BIFs) are widely viewed as direct chemical precipitates from proximal volcanic-hydrothermal vents. However, a systematic multiple sulfur isotope study of oxide-facies BIF from a type locality in the ca. 2.74 Ga Temagami greenstone belt reveals mainly bacterial turnover of atmospheric elemental sulfur in the host basin rather than deposition of hydrothermally cycled seawater sulfate or sulfur from direct volcanic input. Trace amounts of chromium reducible sulfur that were extracted for quadruple sulfur isotope (32S-33S-34S-36S) analysis record the previously known mass-independent fractionation of volcanic SO2 in the Archean atmosphere (S-MIF) and biological sulfur cycling but only minor contributions from juvenile sulfur, despite the proximity of volcanic sources. We show that the dominant bacterial metabolisms were iron reduction and sulfur disproportionation, and not sulfate reduction, consistent with limited availability of organic matter and the abundant ferric iron deposited as Fe(OH)3. That sulfur contained in the BIF was not a direct volcanic-hydrothermal input, as expected, changes the view of an important archive of the Neoarchean sulfur cycle in which the available sulfur pools were strongly decoupled and only species produced photochemically under anoxic atmospheric conditions were deposited in the BIF-forming environment.

  20. The nature of Mesoarchaean seawater and continental weathering in 2.85 Ga banded iron formation, Slave craton, NW Canada

    Science.gov (United States)

    Haugaard, Rasmus; Ootes, Luke; Creaser, Robert A.; Konhauser, Kurt O.

    2016-12-01

    Banded iron formations (BIF) have been extensively used as proxies to infer the chemical composition of ancient bulk seawater. However, their proximity to ancient crust suggests that they might also be used to reveal the composition of emergent continental landmass at the time of their deposition. Here we use the combination of geochemistry and Sm-Nd isotopes on a layer-by-layer basis to interpret the relative contributions of hydrothermal, hydrogenous and terrestrial input to one of the oldest documented Superior-type BIF in the world. The ∼2.85 Ga Central Slave Cover Group BIF is deposited within a rift basin related to a continental margin and is found associated with basement gneisses, as well as shoreline and shallow-shelf type facies, such as fuchsitic quartzite and pebble-to-cobble conglomerate, that confirm a near-shore depositional setting for the BIF. The BIF ranges from a pure chemical oxide (magnetite)-silicate (grunerite + actinolite) sediment with low Al2O3 (aged BIF. High-resolution geochemistry shows that there is more silica (19.4 wt.% SiO2) in the iron bands than iron (8.7 wt.% Fe2O3) in the silica bands, implying that dissolved Fe2+ came to the BIF site in pulses and that silica likely represents background deposition. Consistently radiogenic εNd(t) values for the iron bands (average +1.7) show that the dissolved REY in the source water during ferric iron precipitation was provided by submarine hydrothermal fluids with relatively uniform 143Nd/144Nd. The silica bands, by contrast, reveal high variation in seawater 143Nd/144Nd as evident from the bimodal εNd(t) distribution with one segment exhibiting negative εNd(t) values averaging -1.1 and another with positive εNd(t) values averaging +2.5. This suggests input of dissolved REY into the upper seawater from weathering of isotopically different crustal components in the source region. Collectively, we speculate that the low REY in the upper seawater and the overall low Ni content implies a

  1. [Potential endocrine disrupting effects of bifenthrin in rats].

    Science.gov (United States)

    Tan, Yanjun; Wang, Hengjuan; Song, Yan; Yang, Hui; Jia, Xudong; Li, Ning

    2012-05-01

    To study the potential endocrine disrupting effects of bifenthrin (BIF) by using uterotrophic assay and Hershberger assay. In uterotrophic assay, 60 female SD rats were randomly divided into 6 groups, 10 rats per group. Rats in bifenthrin-treated groups were given different doses of bifenthrin (1.47, 4.41 and 13.23 mg/kg BW by gavage for 3 consecutive days). Rats in negative control groups were given corn oil by gavage. Rats in ethinyl estradiol (EE) oral positive control groups were given EE 1.0 microg/kg BW by gavage. Rats in EE injected positive groups were given 0.6 microg/kg BW EE by subcutaneously injection while given corn oil by gavage. At necropsy, the wet and blotted uteri were weighed. The relative uteri weights were calculated, and the histology of uteri was observed. In Hershberger assay, 60 castrated male SD rats were randomly divided into 6 groups, with 10 rats in each group. Rats in BIF-treated groups were given different doses of BIF (1.4, 4.2 and 12.6 mg/kg BW) by gavage. Flutamide (3.0 mg/kg BW) were given to animals in the positive control group by gavage. Rats in the negative control group and testosterone propionate group were given corn oil by gavage for 10 consecutive days. Rats in all groups except the negative control group were also treated with testosterone propionate (TP, 0.2 mg/kg BW) by subcutaneous injection. At necropsy, ventral prostate (VP), seminal vesicle plus fluids and coagulating glands (SVCG), levator ani-bulbocavernosus muscle (LABC), paired Cowper's glands (COW) and the glands penis (GP), liver, kidneys, adrenals were weighed. Serum triiodothyronine (T3) and thyroxine (T4) were determined. In uterotrophic assay, compared with the negative control group, the mean relative wet weight and relative blotted weight of uterine were increased significantly in the female rats given by BIF at 13.23 mg/kg BW for 3 days (P < 0.05). BIF resulted in a significant increase of epithelial cell heights of uteri at 4.41 and 13.23 mg/kg BW

  2. Alteration mineral mapping for iron prospecting using ETM+ data, Tonkolili iron field, northern Sierra Leone

    Science.gov (United States)

    Mansaray, Lamin R.; Liu, Lei; Zhou, Jun; Ma, Zhimin

    2013-10-01

    The Tonkolili iron field in northern Sierra Leone has the largest known iron ore deposit in Africa. It occurs in a greenstone belt in an Achaean granitic basement. This study focused mainly on mapping areas with iron-oxide and hydroxyl bearing minerals, and identifying potential areas for haematite mineralization and banded iron formations (BIFs) in Tonkolili. The predominant mineral assemblage at the surface (laterite duricrust) of this iron field is haematitegoethite- limonite ±magnetite. The mineralization occurs in quartzitic banded ironstones, layered amphibolites, granites, schists and hornblendites. In this study, Crosta techniques were applied on Enhanced Thematic Mapper (ETM+) data to enhance areas with alteration minerals and target potential areas of haematite and BIF units in the Tonkolili iron field. Synthetic analysis shows that alteration zones mapped herein are consistent with the already discovered magnetite BIFs in Tonkolili. Based on the overlaps of the simplified geological map and the remote sensing-based alteration mineral maps obtained in this study, three new haematite prospects were inferred within, and one new haematite prospect was inferred outside the tenement boundary of the Tonkolili exploration license. As the primary iron mineral in Tonkolili is magnetite, the study concludes that, these haematite prospects could also be underlain by magnetite BIFs. This study also concludes that, the application of Crosta techniques on ETM+ data is effective not only in mapping iron-oxide and hydroxyl alterations but can also provide a basis for inferring areas of potential iron resources in Algoma-type banded iron formations (BIFs), such as those in the Tonkolili field.

  3. Estimating the hemodynamic influence of variable main body-to-iliac limb length ratios in aortic endografts.

    Science.gov (United States)

    Georgakarakos, Efstratios; Xenakis, Antonios; Georgiadis, George S

    2018-02-01

    We conducted a computational study to assess the hemodynamic impact of variant main body-to-iliac limb length (L1/L2) ratios on certain hemodynamic parameters acting on the endograft (EG) either on the normal bifurcated (Bif) or the cross-limb (Cx) fashion. A customary bifurcated 3D model was computationally created and meshed using the commercially available ANSYS ICEM (Ansys Inc., Canonsburg, PA, USA) software. The total length of the EG, was kept constant, while the L1/L2 ratio ranged from 0.3 to 1.5 in the Bif and Cx reconstructed EG models. The compliance of the graft was modeled using a Fluid Structure Interaction method. Important hemodynamic parameters such as pressure drop along EG, wall shear stress (WSS) and helicity were calculated. The greatest pressure decrease across EG was calculated in the peak systolic phase. With increasing L1/L2 it was found that the Pressure Drop was increasing for the Cx configuration, while decreasing for the Bif. The greatest helicity (4.1 m/s2) was seen in peak systole of Cx with ratio of 1.5 whereas its greatest value (2 m/s2) was met in peak systole in the Bif with the shortest L1/L2 ratio (0.3). Similarly, the maximum WSS value was highest (2.74Pa) in the peak systole for the 1.5 L1/L2 of the Cx configuration, while the maximum WSS value equaled 2 Pa for all length ratios of the Bif modification (with the WSS found for L1/L2=0.3 being marginally higher). There was greater discrepancy in the WSS values for all L1/L2 ratios of the Cx bifurcation compared to Bif. Different L1/L2 rations are shown to have an impact on the pressure distribution along the entire EG while the length ratio predisposing to highest helicity or WSS values is also determined by the iliac limbs pattern of the EG. Since current custom-made EG solutions can reproduce variability in main-body/iliac limbs length ratios, further computational as well as clinical research is warranted to delineate and predict the hemodynamic and clinical effect of variable

  4. Nutrición, suplementación, anemia y embarazo

    OpenAIRE

    Sánchez Salazar, Francisca Rosa; Trelles Aguabella, Edilia; Terán García, Reineria María; Pedroso Hernández, Patricia

    2001-01-01

    Se estudió, en el Hospital Ginecoobstétrico “Eusebio Hernández”, durante el período 1996 al 1997, a 180 gestantes, cuyas edades estaban entre 20 y 29 años, con anemia ferropénica. El objetivo fue conocer el efecto de la atención nutricional y la suplementación con hierro sobre los niveles de hierro sérico. Se crearon 2 grupos de 90 embarazadas cada uno: el grupo estudio, intolerantes a las sales ferroosas por vía bucal, recibió bioestimulin a razón de 9 mg de hierro hemínico diario y el contr...

  5. CONCENTRACIÓN MAGNÉTICA APLICADA A RELAVE DE COBRE

    Directory of Open Access Journals (Sweden)

    Luis Valderrama Campusano

    2015-02-01

    Full Text Available Este trabajo tiene como objetivo desarrollar un circuito de concentración magnética de baja intensidad para tratar relave producido en el tratamiento de minerales de cobre. Para este estudio fueron recolectadas muestras de 27 calicatas construidas y distribuidas a lo largo de la corona del tranque de relaves de la Planta Manuel Antonio Matta de la Empresa Nacional de Minería. El análisis mineralógico indicó la presencia de cuarzo, ortoclasa, magnetita, actinolita, biotita y clinocloro ferroso, albita cálcica, calcita, hematita, pirita, pirrotina y calcopirita. El análisis químico mostró un contenido de hierro total de 18,5% y de hierro magnético de 15,2%. Pruebas realizadas en un Tubo Davis indican que se puede obtener un concentrado con ley de 66,4% de hierro, 3,9% SiO2, 0,70% Al2O3, 0,69% de MgO, 0,60% de CaO y 0,178 de azufre, siendo la recuperación de hierro del 79,2%. Se realizaron pruebas de concentración, a escala de laboratorio, en un separador magnético WLIMS. El concentrado rougher del separador magnético fue remolido hasta una granulometría cuyo P80 es de 50 mm, siguiendo luego  pruebas de limpieza, que entregaron un producto final con una ley de hierro de 63,1 %, hierro magnético 61,83 %, azufre 0,23%, SiO2  7%, Al2O3 1,16%, CaO 0,52% y MgO 0,52%.

  6. Evaluación de proteína C reactiva, velocidad de sedimentación globular, reticulocitos y ancho de distribución eritrocitaria, en niños menores de 5 años con anemia por déficit de hierro, en Cumaná, Venezuela | Evaluation of C reactive protein, erythrocyte sedimentation rate, reticulocytes and erithrocyte distribution width, in children under 5 years old with iron deficiency anemia, in Cumaná, Venezuela

    Directory of Open Access Journals (Sweden)

    Erika Hannaoui

    2017-11-01

    Full Text Available In order to evaluate C-reactive protein, rate of globular sedimentation, reticulocytes and erythrocyte distribution width, in infants with iron deficiency anemia, 114 children of both genders were studied, aged 0 to 5 years, who attended the pediatric consultation of three health centers in the city of Cumana, Sucre state. The infants were divided into three groups: 35 apparently healthy children formed the control group, 59 children enrolled in iron deficiency anemia and 20 children with anemia from other causes. Each infant was determined the levels of serum iron, ferritin, C-reactive protein (CRP, hemoglobin, hematocrit, hematimetric indices (MCHC and MCV, red cell distribution width (ADE, erythrocyte sedimentation rate (ESR and percentage reticulocyte. An ANOVA statistical analysis was applied to determine possible differences between the evaluated parameters. There were highly significant differences in the levels of iron, hemoglobin, hematocrit, MCHC, MCV and ADE among the three groups studied; while ferritin variables, reticulocytes, CRP and ESR showed no significant differences among these groups. The results allow to conclude that the determination of iron and hematological parameters are useful tools for diagnosis and for monitoring patients with iron deficiency anemia. It is recommended that the ADE be included within the profile of exams for such patients in order to assess the degree of anisocitosis in iron deficiency anemia, and thus lead doctors to a quick and accurate diagnosis as quickly as possible.

  7. Pulmón del soldador de arco

    Directory of Open Access Journals (Sweden)

    Luciana Molinari

    2010-12-01

    Full Text Available La siderosis del soldador o neumoconiosis siderótica fue descripta por Doig y McLaughlin en 1936 como una enfermedad pulmonar causada por la inhalación crónica de polvo de hierro en soldadores de arco eléctrico. Presentamos un caso de siderosis del soldador asociada a aumento de los niveles de ferritina, sin hallazgo de depósito de hierro en otros órganos y sin causas evidentes de hemosiderosis secundaria.

  8. Estudio poblacional de prevalencia de anemia ferropénica en La Plata y sus factores condicionantes

    OpenAIRE

    Marín, Gustavo Horacio

    2006-01-01

    La anemia es una de las mayores causales de muerte en la población mundial, y constituye el problema nutricional más grave en el mundo. La anemia y la deficiencia de hierro afectan a aproximadamente mil ochocientos millones de personas. Entre los grupos más afectados figuran las mujeres en edad fértil debido a las pérdidas de sangre en las menstruaciones; las embarazadas, ya que tienen un aumento en las demandas de sangre que determina que los requerimientos de hierro de su organismo no pueda...

  9. Efecto de lactoferrina bovina en la formación de biofilms en cepas clínicas de E. coli enteroagregativa

    Directory of Open Access Journals (Sweden)

    Cecilia Coveñas

    Full Text Available Objetivos. Determinar el efecto de lactoferrina bovina (bLf en la formación de biofilms en cepas clínicas de Escherichia coli enteroagregativa (EAEC, y si este efecto es independiente del hierro. Materiales y métodos. Se utilizaron dos métodos: (a cualitativo, mediante observación directa por microscopia óptica, y (b cuantitativo, lecturas de los valores de absorbancia mediante lector de ELISA en presencia de bLf en concentraciones de 0,01mg/mL y 1mg/mL, con y sin hierro, y no bLf (control, en 122 cepas de EAEC para el método cuantitativo (60 cepas de niños con diarrea y 62 de niños sanos y 31 cepas para el método cualitativo. Resultados. (a Método cualitativo: se evaluaron 31 cepas, con y sin hierro. Sin hierro la formación de biofilms fue de 77% (24/31 en el grupo control versus 58% (14/31 con bLf de 0,01 mg/mL y 4% (1/31 con 1 mg/mL. Con hierro la formación de biofilms fue 90% (28/31 en el grupo control versus 55% (17/31 con bLf de 0,01 mg/mL y 4% (1/31 a 1 mg/mL. (b Método cuantitativo: sin hierro la absorbancia medida a OD 560 nm del grupo control fue 0,7 ± 0,5 versus 0,4 ± 0,3 con bLf 0,01mg/mL y 0,3 ± 0,2 con bLf de 1 mg/mL (p<0,0001. Esta disminución en presencia de bLf incluso se dio con hierro. Conclusiones. La bLf tiende a disminuir la formación de biofilms, mostrando un efecto inhibitorio en las cepas clínicas de EAEC, este efecto no es hierro-dependiente

  10. Evaluación de la educación nutricional y un suplemento para prevenir la anemia durante la gestación

    OpenAIRE

    Parra, Beatriz Elena; Manjarrés, Luz Mariela; Gómez, Alba Lucía; Alzate, Dora María; Jaramillo, María Clemencia

    2005-01-01

    Introducción. Las deficiencias de hierro y ácido fólico son la causa de graves problemas de salud en la mujer gestante y en el niño, con implicaciones negativas para el desarrollo económico y social de los países. Objetivos. Evaluar los cambios de conocimientos sobre funciones, alimentos fuentes y biodisponibilidad del hierro y folatos, el consumo y la tolerancia de un suplemento y el comportamiento de los índices globulares en gestantes del programa prenatal de la Empresa Social del Estado H...

  11. Composición y procedimiento de obtención de azulejos cerámicos de gres porcelánico reforzados

    OpenAIRE

    Fernández Lozano, José Francisco; Jiménez Reinosa, Julián; Vela Carrascosa, Enrique; García Tomas, Fernando

    2012-01-01

    Composición y procedimiento de obtención de azulejos cerámicos de gres porcelánico reforzados. La presente invención trata de un gres porcelánico que comprende cristales de silicatos seleccionados de la lista que comprende silicatos de magnesio, silicatos de hierro o silicatos de magnesio y hierro, donde los cristales están homogéneamente distribuidos y tienen un tamaño medio de de 20nm a 1000nm, preferiblemente de 50 a 500nm. Asimismo esta invención trata del proce...

  12. Composición y procedimiento de obtención de azulejos cerámicos de gres porcelánico reforzados

    OpenAIRE

    Fernández Lozano, José Francisco; Jiménez Reinosa, Julián; Vela Carrascosa, Enrique; García Tomas, Fernando

    2012-01-01

    La presente invención trata de un gres porcelánico que comprende cristales de silicatos seleccionados de la lista que comprende silicatos de magnesio, silicatos de hierro o silicatos de magnesio y hierro, donde los cristales están homogéneamente distribuidos y tienen un tamaño medio de de 20nm a 1000nm, preferiblemente de 50 a 500nm. Asimismo esta invención trata del procedimiento de obtención de dichos productos de gres porcelánico

  13. Evaluación de los niveles plasmáticos de hepcidina en pacientes con anemia ferropénica y cáncer colorectal

    OpenAIRE

    Vila Montañés, María

    2017-01-01

    RESUMEN TESIS DOCTORAL TITULO: “Evaluación de los niveles plasmáticos de hepcidina en pacientes con anemia ferropénica y cáncer colorectal.” AUTOR: María Vila Montañés INTRODUCCIÓN El objetivo general de este trabajo fue determinar los niveles plasmáticos de hepcidina y su posible relación con el tratamiento con hierro intravenoso. El hierro es una terapia clave en el manejo de la anemia preoperatoria en los pacientes con cáncer colorectal. La anemia preoperatoria es una en...

  14. Patrones ferrocin??ticos en la beta-talasemia minor

    OpenAIRE

    P??rez Blanco, Francisco Jos??; Jim??nez Jim??nez, M. J.; Mart??n Fern??ndez, A.

    2014-01-01

    Objetivos: Estudiar los par??metros del metabolismo del hierro en la beta-talasemia minor. Casu??stica y M??todos: Se estudian 58 sujetos (30 hombre y 28 mujeres) de edades entre 18-72 a??os diagnosticados de talasemia beta minor. Como controles se estudiaron 30 hombres y 28 mujeres del mismo espectro de edad. El estudio hematol??gico se realiz?? en el Coulter Counter, el bioqu??mico en el autoanalizador Hitachi, la hemoglobina A2 mediante electroforesis en celogel. El hierro m...

  15. La electrocoagulación, una alternativa al proceso convencional de coagulación de aguas residuales

    OpenAIRE

    Cañizares, Pablo; Martínez, Fabiola; Sáez, Cristina; Rodrigo, Manuel

    2009-01-01

    El tratamiento de residuos consistentes en dispersiones acuosas coloidales, o en emulsiones de aceite en agua, se suele realizar mediante la adición de reactivos al residuo, normalmente disoluciones que contienen sales de hierro y aluminio. Una alternativa a la dosificación de estas disoluciones es la generación por vía electroquímica de los iones necesarios para desestabilizar los coloides de la dispersión, o las microgotas de la emulsión, mediante la utilización de planchas de hierro o alum...

  16. Síntesis y caracterización del lactato ferroso para la fortificación de alimentos infantiles

    OpenAIRE

    Anabel Pacios; Yiliam Cruz; Antonio Bell; Emilia Carrera; Georgina Michelena

    2009-01-01

    Para prevenir y controlar la deficiencia de hierro, el MINAL, el MINSAP y la UNICEF están llevando a cabo un proyecto para la fortificación con hierro de los purés de frutas de la canasta básica. Esta suplementación hace que estos alimentos tengan un alto porcentaje de la dosis diaria de vitaminas y minerales que los niños deben ingerir. El programa de fortificación de alimentos infantiles se soporta sobre la importación de lactato ferroso. Con el objetivo de disminuir el costo de este progra...

  17. Community Empowerment through Islamic Microfinances: Perceptions in Comparison

    Directory of Open Access Journals (Sweden)

    Lathif Hanafir Rifqi

    2017-04-01

    Full Text Available BMT (Islamic saving and loan cooperative has continuosly been one of the Islamic microfinance institutions playing a significant role in empowering economic society. There has been a number of research discussing on the effort, however none of them discussed on the perception between the empowers and the empowered group. Comparing these perceptions is a salient effort to find similarities or differencess of perceptions. This research seeks to compare empowerment perception between two organizations. One hand hand, the first party taking BMT BIF Ledok Timoho as the empowering organization and on the other hand focusing on a group of women's empowerment Ledok Timoho. Gathering data through doing observation and in-depth interview had been employed with selecting the purposive informants that contains a BMT BIF and four empowerment group representatives. To conclude, this research found that are similarities of perceptions on empowerment goals, process, outcomes and constraints.

  18. Dynamic load indicators for take-off-landing sequence in blocks and attacks of elite female volleyball players.

    Science.gov (United States)

    Kabaciński, Jarosław; Dworak, Lechosław Bogdan; Murawa, Michał; Rzepnicka, Agata

    2016-01-01

    Dynamic loads during landings determined by the ground reaction forces (GRFs) may elaborate internal loads and increase the risk of overload knee injuries as a result of performing volleyball jumps many times. The study dealt with a biomechanical assessment of dynamic load indicators in female volleyball players for the motion sequence of take-off-landing in blocks and attacks. Twelve professional female volleyball players participated in the study. Blocks and attacks were filmed by two cameras. GRFs vs. time graphs were recorded with the use of a force platform. Values of dynamic load indicators in terms of the relations of peak of vertical component of GRF, build-up index of this force (BIF), and power output (P) during landing to the vGRF, BIF and P during take-off (L/T) were calculated. The statistically significant ( p volleyball players.

  19. Experience and Strategy of Biodiversity Data Integration in Taiwan

    Directory of Open Access Journals (Sweden)

    K T Shao

    2013-02-01

    Full Text Available The integration of Taiwan's biodiversity databases started in 2001, the same year that Taiwan joined GBIF as an associate participant. Taiwan, hence, embarked on a decade of integrating biodiversity data. Under the support of NSC and COA, the database and websites of TaiBIF, TaiBNET (TaiCOL, TaiBOL, and TaiEOL have been established separately and collaborate with the GBIF, COL, BOL, and EOL respectively. A cross-agency committee was thus established in Academia Sinica in 2008 to formulate policies on data collection and integration as well as the mechanism to make data available to the public. Any commissioned project will hereafter be asked to include these policy requirements in its contract. So far, TaiBIF has gained recognition in Taiwan and abroad for its efforts over the past several years. It can provide its experience and insights for others to reference or replicate.

  20. Holey fibers for low bend loss

    Science.gov (United States)

    Nakajima, Kazuhide; Saito, Kotaro; Yamada, Yusuke; Kurokawa, Kenji; Shimizu, Tomoya; Fukai, Chisato; Matsui, Takashi

    2013-12-01

    Bending-loss insensitive fiber (BIF) has proved an essential medium for constructing the current fiber to the home (FTTH) network. By contrast, the progress that has been made on holey fiber (HF) technologies provides us with novel possibilities including non-telecom applications. In this paper, we review recent progress on hole-assisted type BIF. A simple design consideration is overviewed. We then describe some of the properties of HAF including its mechanical reliability. Finally, we introduce some applications of HAF including to high power transmission. We show that HAF with a low bending loss has the potential for use in various future optical technologies as well as in the optical communication network.

  1. “extracción, purificación parcial y secado de la enzima bromelina obtenida a partir del corazón de la piña (ananas comosus)”.

    OpenAIRE

    Quinde Fuentes, Carmina Stefania; Sánchez Lluguín, Nancy Viviana

    2013-01-01

    El presente artículo tuvo como objetivo la purificación parcial de la enzima bromelina mediante el sistema bifásico acuoso (SBA), evaluando el efecto del pH y las concentraciones de los componentes PEG 8000 y sales fosfato del sistema. La bromelina fue extraída del corazón de la piña de la variedad Milagreña mediante solución buffer a 4°c con EDTA, cisteína y fosfato disódico anhídrido. El mejor resultado de purificación obtenido en el sistema bifásico acuoso fue el que consistió de 16% PEG, ...

  2. BiFS-based approaches to remote display for mobile thin clients

    Science.gov (United States)

    Mitrea, M.; Simoens, P.; Joveski, B.; Marshall, J.; Taguengayte, A.; Prêteux, F.; Dhoed, B.

    2009-08-01

    Under the framework of the FP-7 European MobiThin project, the present study addresses the issue of remote display representation for mobile thin client. The main issue is to design a compressing algorithm for heterogeneous content (text, graphics, image and video) with low-complex decoding. As a first step in this direction, we propose a novel software architecture, based on BiFS - Binary Format for Scenes (MPEG-4 Part 11). On the server side, the graphical content is parsed, converted and binary encoded into the BiFS format. This content is then streamed to the terminal, where it is played on a simple MPEG player. The viability of this solution is validated by comparing it to the most intensively used wired solutions, e.g. VNC - Virtual Network Computing.

  3. Range doppler dynamic range considerations for dechirp on receive radar

    CSIR Research Space (South Africa)

    De Witt, JJ

    2008-10-01

    Full Text Available of (11) and the first three terms of (12). The maximum value of β is related to the available IF bandwidth (BIF in Hz) as max[β]=−2piBIF θp/∆fθ, if we let ∆fθ (= a/ωθ) denote the frequency span (in Hz) of one period of the phase error function... in OTHR,” 6th International Conference on Signal Processing, vol. 2, pp. 1461 – 1464, 26-30 Aug 2002. [7] G. Arfken and H. Weber, Mathematical Methods for Physicists, 5th ed. Harcourt/Academic Press, 2000. [8] X. Zeng, Q. Hu, J. He, Q. Tu, and X. Yu...

  4. Taking plastics packaging to the future through improving barrier properties

    CSIR Research Space (South Africa)

    Labuschagne, Philip W

    2011-11-01

    Full Text Available , trimethylaluminium) + O2, Ar ? Covalently bonded to substrate ? adhesion ?; brittleness ? ? Process variables: power, pressure, O2 % ? BIF PET: 5 ? 200x; PP: 2 ? 60x ? Prone to pinholes (contaminants), microcracks: Supporting the Manufacturing and Materials... the Manufacturing and Materials Industry in its quest for global competitiveness orting the Manufacturing and Materials Industry in it quest for global competitiveness CSIR Manufacturing and Materials Technology Taking Plastics Packaging to the Future Through...

  5. The Paleo-environmental significance of the iron-formations and iron-rich mudstones of the Mesoarchean Witwatersrand-Mozaan Basin, South Africa

    OpenAIRE

    2009-01-01

    M.Sc. The Mesoarchean Witwatersrand and Pongola Supergroups of South Africa are the oldest, well preserved supracratonic successions worldwide. Various banded iron formation (BIF) and iron-rich mudstone units occur within the West Rand Group of the Witwatersrand Supergroup and the Mozaan Group of the Pongola Supergroup. A granular iron formation (GIF) occurs in a single unit in the Nconga Formation of the Mozaan Group. The Witwatersrand Supergroup and Mozaan Group have been lithostratigrap...

  6. Coherent Exciton and Biexciton Nonlinearities in Semiconductor Nanostructures: Effects of Disorder

    DEFF Research Database (Denmark)

    Langbein, Wolfgang; Borri, Paola; Hvam, Jørn Märcher

    1999-01-01

    -space filling nonlinearity, excitation-induced dephasing (EID) and biexciton formation (BIF) are important. EID leads to a strong dependence of the signal on the angle between the linear input polarizations. We find that EID persists in inhomogeneous systems, showing that the mutual density-dependent dephasing...... and non-exponential signal decay in delay time. For inhomogenous broadenings larger than the biexciton binding energy, we find an enhanced biexciton binding energy, and a quenching of the oscillator strength of the unbound biexciton....

  7. Immunostimulatory effect of faecal Bifidobacterium species of breast-fed and formula-fed infants in a PBMC/CaCO-2 coculture system

    OpenAIRE

    Pozo Rubio, Tamara; Mujico, Jorge R.; Marcos, Ascensión; Puertollano, E; Nadal, Inmaculada; Sanz, Yolanda; Nova, Esther

    2011-01-01

    Bifidobacterium spp. typical of the human intestinal microbiota are believed to influence the balance of immune responses in the intestinal mucosa. Aim: To investigate the effect of different bifidobacterial species and mixtures of them in in vitro experiments with PBMCs and CaCo-2 cells. Methods: Bifidobacterium adolescentis; Bifidobacterium angulatum; Bifidobacterium breve; Bifidobacterium catenulatum; Bifidobacterium infantis; Bifidobacterium longum; and two combinations of these bif...

  8. Phototrophic Fe(II-oxidation in the chemocline of a ferruginous meromictic lake

    Directory of Open Access Journals (Sweden)

    Xavier Alexis eWalter

    2014-12-01

    Full Text Available Precambrian Banded Iron Formation (BIF deposition was conventionally attributed to the precipitation of iron-oxides resulting from the abiotic reaction of ferrous iron (Fe(II with photosynthetically-produced oxygen. Earliest traces of oxygen date from 2.7 Ga, thus raising questions as to what may have caused BIF precipitation before oxygenic photosynthesis evolved. The discovery of anoxygenic phototrophic bacteria thriving through the oxidation of Fe(II has provided support for a biological origin for some BIFs, but despite reports suggesting that anoxygenic phototrophs may oxidize Fe(II in the environment, a model ecosystem of an ancient ocean where they are demonstrably active was lacking. Here we show that anoxygenic phototrophic bacteria contribute to Fe(II oxidation in the water column of the ferruginous sulfate-poor, meromictic lake La Cruz (Spain. We observed in-situ photoferrotrophic activity through stimulation of phototrophic carbon uptake in the presence of Fe(II, and determined light-dependent Fe(II-oxidation by the natural chemocline microbiota. Moreover, a photoferrotrophic bacterium most closely related to Chlorobium ferrooxidans was enriched from the ferruginous water column. Our study for the first time demonstrates a direct link between anoxygenic photoferrotrophy and the anoxic precipitation of Fe(III-oxides in a ferruginous water column, providing a plausible mechanism for the bacterial origin of BIF’s before the advent of free oxygen.

  9. Recent developments in bend-insensitive and ultra-bend-insensitive fibers

    Science.gov (United States)

    Boivin, David; de Montmorillon, Louis-Anne; Provost, Lionel; Montaigne, Nelly; Gooijer, Frans; Aldea, Eugen; Jensma, Jaap; Sillard, Pierre

    2010-02-01

    Designed to overcome the limitations in case of extreme bending conditions, Bend- and Ultra-Bend-Insensitive Fibers (BIFs and UBIFs) appear as ideal solutions for use in FTTH networks and in components, pigtails or patch-cords for ever demanding applications such as military or sensing. Recently, however, questions have been raised concerning the Multi-Path-Interference (MPI) levels in these fibers. Indeed, they are potentially subject to interferences between the fundamental mode and the higher-order mode that is also bend resistant. This MPI is generated because of discrete discontinuities such as staples, bends and splices/connections that occur on distance scales that become comparable to the laser coherent length. In this paper, we will demonstrate the high MPI tolerance of all-solid single-trench-assisted BIFs and UBIFs. We will present the first comprehensive study combining theoretical and experimental points of view to quantify the impact of fusion splices on coherent MPI. To be complete, results for mechanical splices will also be reported. Finally, we will show how the single-trench- assisted concept combined with the versatile PCVD process allows to tightly control the distributions of fibers characteristics. Such controls are needed to massively produce BIFs and to meet the more stringent specifications of the UBIFs.

  10. Poema: Mithistorema

    Directory of Open Access Journals (Sweden)

    Jorge Seferis

    1966-08-01

    Full Text Available Hemos esperado al mensajero tres años, vigilando los pinos, la playa las estrellas. Nos uníamos al hierro del arado o a la quilla del navío para tratar de descubrir el Primer gérmen y que el drama muy antiguo recomenzara.

  11. Nuevas variedades de papa combaten la pobreza y la desnutrición ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    en Colombia, donde la desnutrición y la deficiencia de hierro son frecuentes ... paron en la prueba 3 755 agricultores, escuelas agrícolas, orga- nizaciones ... la venta en todo el país. ... Renaud De Plaen, Jefe de Programa, Ottawa, Canadá.

  12. Acoustic Detection, Behavior, and Habitat Use of Deep-Diving Odontocetes

    Science.gov (United States)

    2011-09-22

    de Estudios de Biologia Marina. Alicante. Spain, Sept. 2010. Escanez A., Guerra A., Gonzalez A., Landeira J., Vicente A., Arranz P., Aguilar N...34Cefalopodos mesopelagicos capturados en las islas de El Hierro u Tenerife durante la campana Zifiocal-I", Sociedad Iberico de Estudios de Biologia

  13. De la geoquimica al paisaje: composicion elemental de los suelos

    NARCIS (Netherlands)

    Martinez-Cortizas, A.; Costa-Casais, M.; Kaal, J.; Ferro-Vazquez, C.; Pontevedra-Pombal, X.; Viveen, W.

    2013-01-01

    El objeto de este libro es el estudio del arte rupestre en la Edad de Bronce hasta la Edad del Hierro en Campo Lameiro (Pontevedra, Galicia), en el que se ha combinado la metodología arqueológica, histórica, etnográfica y paleoambitental, para completar el contexto arqueológico de los petroglifos

  14. Transferring and implementing the general dynamic model of oceanic island biogeography at the scale of island fragments: the role of geological age and topography in plant diversification in the Canaries

    DEFF Research Database (Denmark)

    Otto, Rüdiger; Whittaker, Robert J.; von Gaisberg, Markus

    2016-01-01

    ontogenies, featuring surfaces of varying age. Here, we extend the GDM to apply at a local scale within islands, and test the predictions analytically within individual islands. Location El Hierro, La Palma and Tenerife (Canary Islands). Methods Following the GDM logic, we derive predictions...

  15. Indian Academy of Sciences Conference Series | Indian Academy of ...

    Indian Academy of Sciences (India)

    Author Affiliations. J MONTES1 F REVUELTA2 F BORONDO2. Grupo de Sistemas Complejos, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, Avda. Puerta de Hierro, 2-4, 28040 Madrid, Spain ...

  16. El ornamento estampado en la Arquitectura

    Directory of Open Access Journals (Sweden)

    Alfredo Gredig G.

    1985-06-01

    Full Text Available Los oficios artesanales que tradicionalmente habían estado incluidos en la concepción arquitectónica, como por ejemplo el tallado de la madera, el cincelado de la piedra o la forja del hierro comienzan a desaparecer en la primera mitad del siglo como preocupación de diseño.

  17. A study of stomach contents of Cory's shearwater, Calonectris diomedea borealis (Cory, 1881) (Aves: Procellariidae), from the Macaronesian Islands

    NARCIS (Netherlands)

    Hartog, den J.C.; Clarke, M.R.

    1996-01-01

    Data are presented on the diet of Cory's Shearwater Calonectris diomedea borealis (Cory, 1881) resulting from stomach investigations based on 18 birds from Hierro (Canary Islands), 5 from Selvagem Grande (Selvagens or Salvage Islands), 2 from São Miguel and 1 from São Jorge (Azores), collected

  18. LA ATENCIÓN FARMACÉUTICA: MÁS ALLÁ DE LOS MEDICAMENTOS.

    Directory of Open Access Journals (Sweden)

    Wenceslao Ferrando Pérez

    2005-12-01

    Full Text Available RESUMEN Son conocidos los efectos gastrointestinales que algunos pacientes sufren al tomar sales de hierro en dosis terapéuticas (diarrea, estreñimiento, gastritis.... Estos efectos son leves y transitorios. Los lactantes de menos de seis meses no suelen necesitar suplementos de hierro, salvo los prematuros, en los que sí está indicado un suplemento de hierro a partir del segundo mes de vida. Pero en este caso, un prematuro de dos meses sufrió efectos gastrointestinales al tomar un suplemento de hierro. La Atención Farmacéutica detectó y corrigió en primera instancia este problema de salud a pesar de que el niño no tomaba un medicamento sino un suplemento nutricional.SUMMARY The gastrointestinal effects that some patients undergo when taking iron salts in therapeutic doses (diarrhea, constipation, gastritis,… are known. These effects are slight and transitory. Suckling babies under six months do not usually need iron supplements, except for the premature ones, in which case an iron supplement is indicated from the second month of life onwards. But in this case, a two month premature baby suffered from gastrointestinal effects after taking an iron supplement. The Pharmaceutical Care detected and corrected this health problem in first instance, although the baby was not taking a medicine but a nutritional supplement.

  19. Efecto de la suplementación con una dosis masiva de vitamina A en niños de 6 a 36 meses de edad

    Directory of Open Access Journals (Sweden)

    Robles-Sardin Alma E.

    1998-01-01

    Full Text Available Objetivo. Evaluar el impacto de la suplementación con una dosis masiva de vitamina A en el estado nutricio de dicha vitamina y del hierro, en niños de zonas urbanas marginadas de Hermosillo, Sonora, México. Material y métodos. Se seleccionaron 60 niños (6-36 meses, a los que se les administró una dosis de 100 000 UI (6-12 meses y 200 000 UI (12-36 meses de vitamina A en el Día Nacional de Salud de la Secretaría de Salud (junio de 1994. Se midieron niveles séricos de retinol, carotenoides, hierro, transferrina y ferritina, en tres fases: basal, a las dos semanas y después de tres meses. Resultados. En la primera fase, la mediana de retinol fue 0.7µmol/l; en la segunda aumentó a 0.97µmol/l (p 0.05. Un 6.3% de los niños presentó deficiencia severa de vitamina A al inicio, y no se encontró ningún caso en las fases posteriores a la suplementación. En la fase basal, 42% de los casos presentaron deficiencia moderada y la mayoría fue normal en las siguientes fases. No hubo diferencias en los niveles de hierro y transferrina (p > 0.05, pero sí en ferritina (p < 0.001, lo que indica un mejoramiento en las reservas de hierro a los tres meses. Conclusiones. Las campañas de distribución de dosis masivas pueden tener un impacto importante en el estado nutricio de vitamina A y hierro.

  20. Diagnóstico de la infección micobacteriana diseminada: evaluación de un método sencillo y barato para países en desarrollo

    Directory of Open Access Journals (Sweden)

    Fandinho F. C .O.

    1998-01-01

    Full Text Available Con el desarrollo de la epidemia del síndrome de inmunodeficiencia adquirida (sida, el aislamiento de micobacterias de la sangre se ha convertido en un problema habitual de los laboratorios clínicos. En el presente estudio se evaluaron dos métodos para aislar micobacterias en muestras de sangre de pacientes de sida: 1 la inoculación directa en un medio bifásico y 2 un método no comercializado de lisis por centrifugación. A cada uno de los 50 pacientes de sida con sospecha de enfermedad micobacteriana diseminada se le extrajeron tres muestras de sangre consecutivas a intervalos de 15 minutos. En 70 de 138 muestras de sangre obtenidas de 30 (60% pacientes se detectó crecimiento de micobacterias. A partir de estos cultivos, en 19 pacientes se aisló Mycobacterium tuberculosis y en 11 (37%, el complejo Mycobacterium avium. Los cultivos en que se utilizó el método de lisis por centrifugación fueron positivos en 54% de los pacientes, mientras que esta cifra se redujo a 44% en los cultivos en que se usó el método bifásico (P > 0,05. El porcentaje de muestras positivas al complejo M. avium fue mayor con el método de centrifugación por lisis (91% que con el de inoculación directa en medio bifásico (45,4% (P 0,05. La técnica no comercializada de centrifugación por lisis es barata, fiable y puede constituir un método alternativo para el diagnóstico de micobacteriemia en países en desarrollo.

  1. Age dependent in vitro metabolism of bifenthrin in rat and human hepatic microsomes.

    Science.gov (United States)

    Nallani, Gopinath C; Chandrasekaran, Appavu; Kassahun, Kelem; Shen, Li; ElNaggar, Shaaban F; Liu, Zhiwei

    2018-01-01

    Bifenthrin, a pyrethroid insecticide, undergoes oxidative metabolism leading to the formation of 4'-hydroxy-bifenthrin (4'-OH-BIF) and hydrolysis leading to the formation of TFP acid in rat and human hepatic microsomes. In this study, age-dependent metabolism of bifenthrin in rats and humans were determined via the rates of formation of 4'-OH-BIF and TFP acid following incubation of bifenthrin in juvenile and adult rat (PND 15 and PND 90) and human (18years) liver microsomes. Furthermore, in vitro hepatic intrinsic clearance (CL int ) of bifenthrin was determined by substrate consumption method in a separate experiment. The mean V max (±SD) for the formation of 4'-OH-BIF in juvenile rat hepatic microsomes was 25.0±1.5pmol/min/mg which was significantly lower (pbifenthrin occurs primarily via oxidative pathway with relatively lesser contribution (~30%) from hydrolytic pathway in both rat and human liver microsomes. The CL int values for bifenthrin, determined by monitoring the consumption of substrate, in juvenile and adult rat liver microsomes fortified with NADPH were 42.0±7.2 and 166.7±20.5μl/min/mg, respectively, and the corresponding values for human liver microsomes were 76.0±4.0 and 21.3±1.2μl/min/mg, respectively. The data suggest a major species difference in the age dependent metabolism of bifenthrin. In human liver microsomes, bifenthrin is metabolized at a much higher rate in juveniles than in adults, while the opposite appears to be true in rat liver microsomes. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Sedimentary mechanisms of a modern banded iron formation on Milos Island, Greece

    Directory of Open Access Journals (Sweden)

    E. Chi Fru

    2018-05-01

    Full Text Available An early Quaternary shallow submarine hydrothermal iron formation (IF in the Cape Vani sedimentary basin (CVSB on Milos Island, Greece, displays banded rhythmicity similar to Precambrian banded iron formation (BIF. Field-wide stratigraphic and biogeochemical reconstructions show two temporal and spatially isolated iron deposits in the CVSB with distinct sedimentological character. Petrographic screening suggests the presence of a photoferrotrophic-like microfossil-rich IF (MFIF, accumulated on a basement consisting of andesites in a ∼ 150 m wide basin in the SW margin of the basin. A banded nonfossiliferous IF (NFIF sits on top of the Mn-rich sandstones at the transition to the renowned Mn-rich formation, capping the NFIF unit. Geochemical data relate the origin of the NFIF to periodic submarine volcanism and water column oxidation of released Fe(II in conditions predominated by anoxia, similar to the MFIF. Raman spectroscopy pairs hematite-rich grains in the NFIF with relics of a carbonaceous material carrying an average δ13Corg signature of ∼ −25‰. A similar δ13Corg signature in the MFIF could not be directly coupled to hematite by mineralogy. The NFIF, which postdates large-scale Mn deposition in the CVSB, is composed primarily of amorphous Si (opal-SiO2 ⋅ nH2O while crystalline quartz (SiO2 predominates the MFIF. An intricate interaction between tectonic processes, changing redox, biological activity, and abiotic Si precipitation are proposed to have collectively formed the unmetamorphosed BIF-type deposits in a shallow submarine volcanic center. Despite the differences in Precambrian ocean–atmosphere chemistry and the present geologic time, these formation mechanisms coincide with those believed to have formed Algoma-type BIFs proximal to active seafloor volcanic centers.

  3. NRC Information No. 90-21: Potential failure of motor-operated butterfly valves to operate because valve seat friction was underestimated

    International Nuclear Information System (INIS)

    Rossi, C.E.

    1992-01-01

    In October 1988, at Catawba Nuclear Station Unit 1, a motor-operated butterfly valve in the service water system failed to open under high differential pressure conditions. The licensee concluded that the valve manufacturer, BIF/General Signal Corporation, had underestimated the degree to which the material used in the valve seat would harden with age (the responsibility for these valves has been transferred to Paul-Munroe Enertech). This underestimation of the age hardening had led the manufacturer to assume valve seat friction forces that were less than the actual friction forces in the installed valve. To overcome the larger-than-anticipated friction forces, the licensee's engineering staff recommended the open torque switch for 56 butterfly valves be reset to the maximum allowable value. The systems in which these valves are located include the component cooling water system, service water system, and various ventilation systems. By July 26, 1989, the torque switch adjustments were completed at Catawba Units 1 and 2. After reviewing the final settings, the licensee's engineering staff determined that the actuators for three butterfly valves in the component cooling water system might not be able to overcome the friction forces resulting from maximum seat hardening. On December 13, 1989, the licensee determined that the failure of these BIF/General Signal motor-operated valves (MOVs) could cause a loss of cooling water to residual heat removal system heat exchangers. To resolve the concern regarding the operability of these BIF/General Signal valves, a torque switch bypass was installed on two of the actuators to allow full motor capability during opening

  4. Control de un motor paso a paso: PIC, USB, C#

    OpenAIRE

    Fernández Aragón, Iñigo

    2011-01-01

    El objetivo de este proyecto fin de carrera es crear un equipo con el que comprender y controlar, desde el ordenador, el funcionamiento de un motor paso a paso bifásico de imanes permanentes, a través de una comunicación USB, la ayuda de un microprocesador y el imprescindible driver del motor paso a paso. Uno de los elementos utilizados en el control de un motor paso a paso es el microprocesador, encargado tanto de enviar las consignas al controlador (driver), como de captar...

  5. Utilización de Lepidium Peruvianum Maca, como medio de cultivo para el crecimiento de Trypanosoma Cruzi

    OpenAIRE

    Saldaña C, Charles; Córdova P, Ofelia; Vargas V¹, Franklin

    2006-01-01

    Por sus características nutritivas de alto valor, se ensayó la posible utilidad del Lepidium peruvianum maca, como un medio para cultivar Trypanosoma cruzi. Bajo condiciones experimentales se procedió a incubar epimastigotes de T. cruzi en cuatro medios de cultivo bifásicos diferentes, a base de Lepidium peruvianum maca, los cuales fueron comparados con el medio de cultivo BHI como control. La incorporación de maca como medio de cultivo permitió el crecimiento de Trypanosoma cruzi; se determi...

  6. IT’S NOT JUST A PHASE: IDENTITY CONSTRUCTIONS IN BISEXUAL-IDENTIFIED LGBT ACTIVISTS’ NARRATIVES

    OpenAIRE

    ELIZABETH SARA LEWIS

    2012-01-01

    A presente pesquisa analisa as construções identitárias performativodiscursivas de três ativistas LGBT que se identificam como bissexuais em narrativas sobre o processo de sair do armário e estereótipos, preconceitos e discriminações bifóbicos. As pessoas bissexuais frequentemente são pouco aceitas nos movimentos LGBT, apesar de serem teoricamente incluídas pela letra B na sigla. A bissexualidade é tratada como só uma fase antes de se assumir heterossexual ou homossexual e a...

  7. The chemical conditions of the late Archean Hamersley basin inferred from whole rock and pyrite geochemistry with Δ33S and δ34S isotope analyses

    Science.gov (United States)

    Gregory, Daniel D.; Large, Ross R.; Halpin, Jacqueline A.; Steadman, Jeffery A.; Hickman, Arthur H.; Ireland, Trevor R.; Holden, Peter

    2015-01-01

    The well-preserved late Archean sedimentary rocks of the Fortescue and Hamersley Basins in Western Australia offer fascinating insights into early earth ocean chemistry prior to the Great Oxidation Event (GOE). In this study, we use a combination of whole rock geochemistry, LA-ICPMS trace element analysis of sedimentary pyrite and pyrrhotite and SHRIMP-SI sulfur isotope analyses to elucidate the chemical changes in these sedimentary rocks. These proxies are used to examine chemical conditions of the ocean during the late Archean. Two to three periods of oxygen enrichment prior to the deposition of banded iron formations (BIF) can be identified. One minor stage of general increase in whole rock enrichment factors and trace element content of pyrite is observed up stratigraphy in the Jeerinah Formation, Fortescue Basin and a more substantial stage is present in the Paraburdoo and Bee Gorge Members of the Wittenoom Formation, Hamersley Basin. Some of the trace element enrichments indicate organic matter burial flux (Ni, Cr, Zn, Co and Cu) which suggests an increase in biological productivity. If the increased biological activity reflects an increase in cyanobacteria activity then an associated increase in oxygen is likely to have occurred during the deposition of the Bee Gorge Member. An increase in atmospheric oxygen would result in continental weathering of sulfide and other minerals, increasing the trace element content of the water column via erosion and avoiding excessive depletion of trace elements due to drawdown in seawater. Since some of these trace elements may also be limiting nutrients (such as Mo and Se) for the cyanobacteria, the degree of biological productivity may have further increased due to the increasing amount of trace elements introduced by oxygenation in a positive feedback loop. These periods of increased productivity and oxygen rise stopped prior to the onset of BIF deposition in the Hamersley Basin. This may be due to the ocean reaching an

  8. Directional Validation of Wave Predictions

    Science.gov (United States)

    2007-03-01

    motivators: I) the desire to make the problem more solution is simply to use only variables directly Cx- manageable via frequency-wise integration of direc...ViaW()2 + bi(f), where . = j F(f) d. The calculation in reverse is a, = in, cosO , and b, = ni, sinf0 . Note that if we choose f, andf2 as values close...34). The use of a broader band of frequencies makes the metric more stable, but CALCULATION OF MEAN WAVE DIRECTION AND increases the risk that two

  9. Caracterización del tipo de cavitación mediante dinámica computacional de fluidos para posteriores aplicaciones al estudio experimental del daño por cavitación

    OpenAIRE

    Moll, Flavio; Manuele, Diego; Coussirat Núñez, Miguel Gustavo; Guardo Zabaleta, Alfredo de Jesús; Fontanals García, Alfred

    2011-01-01

    La cavitación se corresponde a una estructura bifásica (líquido-vapor) cuando la presión del líquido disminuye hasta su presión de vapor, pv. Esta disminución de pv puede deberse a diversos factores relacionados con la hidrodinámica del flujo y las propiedades físicas del fluido, pudiendo presentar diferentes características. En la cavitación hidrodinámica, pueden distinguirse efectos que pueden producir un acoplamiento fluido-estructura (lock-in) que puede favorecen la falla del material, só...

  10. Generación directa de vapor con colectores solares cilindro parabólicos Proyecto DIrect Solar Steam (DISS)

    OpenAIRE

    Zarza Moya, Eduardo

    2003-01-01

    La Generación Directa de Vapor (GDV) en los tubos absorbedores de los colectores solares cilindro parabólicos es considerada la opción tecnológica más atractiva para conseguir una sustancial reducción del coste de la energía térmica producida por este tipo de colector solar. Sin embargo, antes de poder comercializar sistemas solares con GDV e s necesario aclarar todas aquellas cuestiones técnicas que conlleva la existencia de un flujo bifásico circulando por el interior de los tubos absorbedo...

  11. Tratamiento de aplicación de tensión en un caso de fobia a la sangre

    OpenAIRE

    Belén Nieto Centeno; Blanca Mas Hesse

    2002-01-01

    La hematofobia se distingue del resto de las fobias específicas por presentar un patrón de respuesta característico consistente, en primer lugar, en la aparición de una subida de presión sanguínea y tensión arterial, seguido de una caída brusca de las mismas que provoca una disminución en el riego cerebral, causante de los mareos y desmayos típicos en este trastorno. A este tipo de respuesta se la denomina respuesta bifásica. Para combatir la brusca bajada de la pre...

  12. Análisis computacional del comportamiento mecánico de cartílago articular basado en un modelo viscoelástico

    OpenAIRE

    Caballero Alemán, Pedro Julio

    2012-01-01

    El Cartílago articular es un tejido biológico, sorprendente como todos ellos, que posee un comportamiento característico dado por sus propiedades físicas y mecánicas. Alrededor del mundo se han propuestos múltiples modelos para describir dicho comportamiento complejo. En el presente trabajo se realiza una simulación del cartílago articular (subdominio) bajo un modelo bifásico poro-elástico lineal, donde se considera al cartílago compuesto por dos fases intrínsecamente incompresibles e inm...

  13. Pulmón del soldador de arco Arc welder's lung

    Directory of Open Access Journals (Sweden)

    Luciana Molinari

    2010-12-01

    Full Text Available La siderosis del soldador o neumoconiosis siderótica fue descripta por Doig y McLaughlin en 1936 como una enfermedad pulmonar causada por la inhalación crónica de polvo de hierro en soldadores de arco eléctrico. Presentamos un caso de siderosis del soldador asociada a aumento de los niveles de ferritina, sin hallazgo de depósito de hierro en otros órganos y sin causas evidentes de hemosiderosis secundaria.Pneumoconiosis of electric arc welder or siderotic pneumoconiosis was described by Doig and McLaughlin in 1936 as a lung disease caused by chronic inhalation of iron fumes in electric arc welders. We present a case report of electric arc welder siderosis associated with high levels of ferritin, without findings of iron deposit in any other organ.

  14. Actividad antianémica de la Cassia grandis L. The antianemic activity of Cassia grandis L.

    Directory of Open Access Journals (Sweden)

    Juana Tillán Capó

    2004-12-01

    Full Text Available La población de la zona oriental de Cuba refiere los efectos beneficiosos del uso tradicional de la Cassia grandis L. en la anemia, con la utilización del polvo seco obtenido del fruto como un suplemento nutricional. El objetivo fue evaluar dicho efecto en un modelo experimental de anemia ferropénica en ratas, inducido por sucesivas extracciones de sangre y administración de una dieta carente de hierro. Todos los animales fueron sometidos durante 15 días a una dieta semisintética deficiente en hierro y a extracciones de sangre 3 veces por semana hasta lograr concentraciones de hemoglobina en sangre menores de 9 g/dL. Se formaron 3 grupos y se mantuvo la misma dieta: grupo I sin suplementar, grupo II suplementado con 15 mg de hierro/kg de dieta y grupo III la misma cantidad de hierro más 750 mg/kg de peso corporal de polvo seco de Cassia grandis L. durante otros 15 días. Al finalizar se determinaron las concentraciones de hierro, hemoglobina y hematócrito en sangre. Las concentraciones medias de hemoglobina al cabo de los 15 días de tratamiento fueron significativamente diferentes en los 3 grupos experimentales, con resultados mayores en el grupo suplementado con hierro y Cassia grandis L.; también en este grupo se observó un incremento significativo de los valores medios de hierro en plasma en relación con los valores obtenidos en los animales no suplementados y en los animales que recibieron solamente hierro en la dieta. El porcentaje de hematócrito no mostró diferencia significativa entre tratamiento. Los resultados corroboran el uso popular y tradicional de la Cassia grandis L. en los estados anémicos, al mejorar la utilización del hiero y la producción de hemoglobina.The population of the eastern zone of Cuba refers to the benefitial effects of the traditional use of Cassia grandis L. in anemia by using dry powder obtained from the fruit as a nutritional supplement. The objective was to evaluate this effect in an

  15. Estabilidad oxidativa del aceite de palma durante el proceso de refinación industrial en Costa Rica

    OpenAIRE

    Zamora, Eduardo; Herrera Ramírez, Carlos Hernán

    2002-01-01

    Se optimizó y validó un método para cuantificar la concentración del hierro y el cobre en aceites vegetales mediante la técnica de espectrofotometría de absorción atómica de llama. Se implementaron los métodos oficiales establecidos por la AOCS para la determinación de los productos oxidados: índices de peróxido (IP) y de p-anisidina (Ip-A), para evaluar el grado de deterioro del aceite de palma y su relación con el contenido de hierro y cobre, durante el proceso de refinación industrial. El ...

  16. Function of Receptor 1 in uptaking transferrin and its relation to iron deficiency and iron gestational preeclampsia

    OpenAIRE

    Gómez-Gutiérrez, Alejandra María; Parra-Sosa, Beatriz Elena; César Bueno-Sánchez, Julio

    2013-01-01

    La anemia ferropénica gestacional afecta al 48 % de las mujeres y se asocia con efectos deletéreos para la madre y el feto. Para la captación del hierro de la gestante es necesaria la expresión en el sincitiotrofoblasto de la glicoproteína receptor 1 de transferrina (TfR1). En ensayos celulares, en modelos animales y en humanos la deprivación de hierro se ha asociado a un aumento en la transcripción y expresión del TfR1, que se ha explicado como un mecanismo compensatorio para la captación de...

  17. Depth of origin of magma in eruptions.

    Science.gov (United States)

    Becerril, Laura; Galindo, Ines; Gudmundsson, Agust; Morales, Jose Maria

    2013-09-26

    Many volcanic hazard factors--such as the likelihood and duration of an eruption, the eruption style, and the probability of its triggering large landslides or caldera collapses--relate to the depth of the magma source. Yet, the magma source depths are commonly poorly known, even in frequently erupting volcanoes such as Hekla in Iceland and Etna in Italy. Here we show how the length-thickness ratios of feeder dykes can be used to estimate the depth to the source magma chamber. Using this method, accurately measured volcanic fissures/feeder-dykes in El Hierro (Canary Islands) indicate a source depth of 11-15 km, which coincides with the main cloud of earthquake foci surrounding the magma chamber associated with the 2011-2012 eruption of El Hierro. The method can be used on widely available GPS and InSAR data to calculate the depths to the source magma chambers of active volcanoes worldwide.

  18. Cirugía magnética ocular en el Hospital San Juan de Dios de Santa Fe de Bogotá

    Directory of Open Access Journals (Sweden)

    José Ramiro Prada Reyes

    1996-10-01

    Full Text Available Nuestros antepasados conocieron, que piedras de óxido negro de hierro (imanes poseían la curiosa propiedad de atraer pequeñas piezas de hierro. Estas piedras fueron encontradas en cantidad en Magnesia, Asia Menor, localidad de la cual se deriva la denominación de magnetos. En cirugía general, desde tiempos inmemoriales, los magnetos han sido empleados para la remoción de cuerpos extraños metálicos alojados en los tejidos del cuerpo humano; así mismo, el imán fue usado para este propósito en la India, antes de la era cristiana.

  19. Molecular phylogenetics of Micromeria (Lamiaceae) in the Canary Islands, diversification and inter-island colonization patterns inferred from nuclear genes.

    Science.gov (United States)

    Puppo, Pamela; Curto, Manuel; Gusmão-Guedes, Joana; Cochofel, Jaqueline; Pérez de Paz, Pedro Luis; Bräuchler, Christian; Meimberg, Harald

    2015-08-01

    Here we reconstruct the evolutionary history of Micromeria in the Canary Islands using eight nuclear markers. Our results show two centers of diversification for Micromeria, one in the eastern islands Gran Canaria and Lanzarote, the other in the western islands, Tenerife, La Palma and El Hierro. Suggested directions of inter-island colonization are the following: Gran Canaria to Lanzarote and La Gomera; Tenerife to La Palma (from the paleoisland of Teno), to El Hierro (from the younger, central part), and to La Gomera and Madeira (from the paleoislands). Colonization of La Gomera probably occurred several times from Gran Canaria and Tenerife. The taxonomic implications of these results are discussed. Incongruence among the different markers was evaluated and, using next generation sequencing, we investigated if this incongruence is due to gene duplication. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Stress barriers controlling lateral migration of magma revealed by seismic tomography

    OpenAIRE

    Mart?, J.; Villase?or, A.; Geyer, A.; L?pez, C.; Tryggvason, A.

    2017-01-01

    Understanding how monogenetic volcanic systems work requires full comprehension of the local and regional stresses that govern magma migration inside them and why/how they seem to change from one eruption to another. During the 2011-2012 El Hierro eruption (Canary Islands) the characteristics of unrest, including a continuous change in the location of seismicity, made the location of the future vent unpredictable, so short term hazard assessment was highly imprecise. A 3D P-wave velocity mode...

  1. Fortificación del arroz para corregir la deficiencia de micronutrientes en niños de 6 a 59 meses de edad

    Directory of Open Access Journals (Sweden)

    Gisely Hijar

    2015-01-01

    Full Text Available Objetivo. Realizar una revisión sistemática de la literatura sobre la eficacia del consumo de arroz fortificado en el incremento de los niveles de hierro y otros micronutrientes en niños de 6 a 59 meses de edad, con la finalidad de evaluar su utilidad como intervención de salud pública. Métodos. La búsqueda se realizó en las bases de datos Medline, Embase, The Cochrane Library y LILACS. Se incluyeron ensayos clínicos aleatorizados (ECA que evaluaron el consumo de arroz fortificado comparado con placebo u otras formas de intervención sobre la mejora de los niveles de hierro y otros micronutrientes. Para evaluar la calidad metodológica, se utilizó la lista de verificación CONSORT®. El riesgo de sesgo de los estudios se evaluó según la metodología de la Colaboración Cochrane®. Resultados. Se incluyeron siete ECA en la revisión. Todos los estudios mostraron mejoras significativas en indicadores del estado nutricional de hierro en los grupos intervenidos, sin reportar efectos adversos. No se evidenció mejoría en los niveles de vitamina A, ni en los indicadores antropométricos de peso y talla como resultado secundario de la intervención. Los estudios incluidos mostraron calidad metodológica moderada. Conclusiones. La fortificación del arroz representó una estrategia de intervención eficaz para corregir la deficiencia de hierro en la población infantil menor de cinco años. Su implementación como medida de salud pública requiere estudios locales que evalúen su efectividad en intervenciones a largo plazo y en mayor escala.

  2. Entre el pensamiento lógico y la reivindicación de la condición humana. Una mirada desde la obra de Ernesto Sábato

    Directory of Open Access Journals (Sweden)

    Wilfer Yepes Muñoz

    2017-12-01

    las abstracciones, al pensamiento mágico, del soñador irremediable e inconforme con las leyes de la lógica de hierro y que, empero, no niega su condición doble: piensa y sueña, sufre y desea; y esta misma dualidad la precisamos en todo momento, porque sin ella morimos, o a causa de la cosificación deshumanizante, o a causa de la ilogicidad extrema.

  3. Efecto magnetocalórico en materiales con transiciones de fase de segundo orden: Optimización de la capacidad de refrigeración

    OpenAIRE

    Caballero Flores, Rafael

    2011-01-01

    La tesis presenta un estudio del efecto magnetocalórico en materiales con transiciones de fase de segundo orden. Se centra esencialmente en la dependencia con el campo magnético aplicado de la variables termodinámicas relevantes del proceso, estudio de aleaciones basadas en hierro para minimizar los costos de los materiales refrigerantes, y fabricación de composites para minimizar los valores de las intensidades del campo requeridas en el proceso de refrigeración.

  4. Location iron-Mantua an area with high securities gives natural radioactivity

    International Nuclear Information System (INIS)

    Alcaide Orpi, J.; Oliveira Acosta, J.; Valdes Hernadez, G.M.; Leal Ramirez, M.R.; Blanco Jorrin, N.

    1998-01-01

    The work shows the high natural radioactivity and the concentration to the natural radioelements (U,Th, Ra, K) it is exists in the sulfurous Hierro Mantua location. The objective is to know the possible radiological risk to that would be subjected the workers during the mining exploitation, because the high gamma radiation doses that could receive and to the risks product the internal contamination due to the inhalation the radon 222 and uranium aerosols and particles

  5. Suplementos Minerales a partir de Anamú Petiveria Alliacea l.) y Plátano (Mussa Paradisí-aca l.)

    OpenAIRE

    Bárbara Luna; María Cristina Melo; Erlinda Handal; Estevan Pérez; Ana C. Rodriguez

    2005-01-01

    Es muy conocido en el mundo el uso de los suplementos nutricionales debido al papel que representan como complementos de la dieta cuando esta no es suficiente para satisfacer los requerimientos nutricionales diarios del hombre, de sustancias tales como los minerales, vitaminas, proteínas, etc., que por la importancia que tienen en el metabolismo se consideran esenciales para la vida. Entre otros minerales, se consideran esenciales para aquel, hierro, zinc, cobre, manganeso, selenio, cromo, co...

  6. ¿Es el gen de la hemocromatosis hereditaria un gen modificador de la enfermedad de Alzheimer familiar en Antioquia?

    Directory of Open Access Journals (Sweden)

    Marlene Jiménez del Río

    2005-03-01

    Full Text Available La hemocromatosis hereditaria (HH es un desorden autosómico recesivo del metabolismo del hierro, que se caracteriza clínicamente por la absorción excesiva de esta metal y su depósito en diferentes tejidos como el hígado, el páncreas, el carazón, las articulaciones yla glándula pituitarua.

  7. Los niveles de ferritina y los marcadores de riesgo cardiovascular se correlacionan con mayor tiempo sedentario auto-reportado en hombres aparentemente sanos

    Directory of Open Access Journals (Sweden)

    Milton F. Suárez, Bact., MSc

    2012-01-01

    Conclusiones: el tiempo sedentario (minutos sentado/semana reportado por los sujetos, se correlacionó de manera positiva con los niveles de ferritina así como con la resistencia a la insulina y los marcadores de riesgo cardiovascular. Los depósitos de hierro corporales estimados como ferritina sérica, al relacionarse con parámetros de sedentarismo, se comportan como un potencial marcador de riesgo cardiovascular.

  8. Dicty_cDB: Contig-U15486-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 3 ( AY442211 ) Drosophila subobscura strain Palma-5 A+T rich reg... 34 1.6 3 ( AY442221 ) Drosophila subobs...phila subobscura strain Palma-1 A+T rich reg... 34 1.6 3 ( AY442209 ) Drosophila subobscura strain Hierro-21...h ... 34 1.6 3 ( AY442212 ) Drosophila subobscura strain Barcelona-12 A+T ric... 34 1.6 3 ( AY442210 ) Droso

  9. Effect of production conditions on the stability of a human bifidobacterial species Bifidobacterium longum in yogurt.

    Science.gov (United States)

    Abe, F; Tomita, S; Yaeshima, T; Iwatsuki, K

    2009-12-01

    Human bifidobacteria are more sensitive to external environmental factors than animal bifidobacteria, and it is difficult to ensure their stable survival in yogurt. The purpose of this investigation was to observe the survival of human bifidobacteria in yogurts produced under various production conditions. Frozen or lyophilized bifidobacteria starters containing Bifidobacterium longum BB536 originally isolated from an infant, and commercial lyophilized yogurt starters were used for yogurt preparation. After producing yogurts under various conditions, the survival of bifidobacteria in these yogurts over various storage periods was observed. Although there were some differences in bifidobacterial survival in yogurt between various production conditions, more than 1.0 x 10(7) CFU g(-1) of Bif. longum survived in yogurt after 35 days' storage at 5 degrees C. Lower fermentation temperature (37 degrees C) and inclusion of Lactococcus lactis in the starter significantly (P yogurt. In this investigation, the human bifidobacterial strain Bif. longum survived adequately in yogurt, although the fermentation temperature and starter composition affect bifidobacterial survival. This investigation indicates that stable probiotic yogurt using human bifidobacteria can be produced by choosing optimal production conditions.

  10. Correlations between the North China Craton and the Indian Shield: Constraints from regional metallogeny

    Directory of Open Access Journals (Sweden)

    Caifeng Li

    2015-11-01

    Full Text Available The correlation between the North China Craton (NCC and the Indian Shield (IND has been a hot topic in recent years. On the basis of ore deposit databases, the NCC and IND have shown broad similarity in metallogenesis from the middle Archaean to the Mesoproterozoic. The two blocks both have three major metallogenic systems: (1 the Archaean BIF metallogenic system; (2 the Paleoproterozoic Cu-Pb-Zn metallogenic system; and (3 the Mesoproterozoic Fe-Pb-Zn system. In the north margin of the NCC and the west margin of the IND, the Archaean BIF-Au-Cu-Pb-Zn deposits had the same petrogenesis and host rocks, the Paleoproterozoic Cu-Pb-Zn deposits were controlled by active belts, and the Mesoproterozoic Fe-Pb-Zn deposits were mainly related to multi-stage rifting. Matching regional mineralization patterns and geological features has established the continental assembly referred to as “NCWI”, an acronym for the north margin of the NCC (NC and the west margin of the IND (WI during the middle Archaean to the Mesoproterozoic. In this assembly, the available geological and metallogenic data from the Eastern Block and active belts of NC fit those from the Dharwar craton and the Aravalli–Delhi–Vindhyan belt of WI, respectively. Moreover, the depositional model and environment of Paleoproterozoic metasedimentary manganese deposits in NCWI implied that the assembly may be located at low latitudes, where the conditions were favorable for dissolving ice and precipitating manganese deposits.

  11. Assessment of stress tolerance acquisition in the heat-tolerant derivative strains of Bifidobacterium animalis subsp. lactis BB-12 and Lactobacillus rhamnosus GG.

    Science.gov (United States)

    Aakko, J; Sánchez, B; Gueimonde, M; Salminen, S

    2014-07-01

    The purpose of this study was to investigate the heat-shock response at molecular level in Lactobacillus rhamnosus GG, Bifidobacterium animalis subsp. lactis BB-12 and their heat-tolerant derivatives and to characterize the changes that make the derivatives more robust in terms of heat stress. The study strains were exposed for 2 h to a heat-shock treatment, Bif. animalis subsp. lactis BB-12 and its derivative at 50°C and the Lact. rhamnosus GG and its derivative at 60°C. Protein synthesis before and after heat shock was examined using proteomics and RT-qPCR. The analysis revealed that the regulation of seven proteins in both strain pairs was modified as a response to heat or between the original and the derivative strain. The comparison of wild-type strains and the heat-tolerant derivatives suggests that the acquisition of heat tolerance in the Bif. animalis subsp. lactis BB-12 derivative is due to a slightly increased constitutive level of chaperones, while in Lact. rhamnosus GG derivative, the main reason seems to be a higher ability to induce the production of chaperones. This study revealed possible markers of heat tolerance in B. lactis and Lact. rhamnosus strains. This study increases our knowledge on how Lactobacillus and Bifidobacterium strains may acquire heat tolerance. These findings may be useful for improving the heat tolerance of existing probiotic strains as well as screening new heat-tolerant strains. © 2014 The Society for Applied Microbiology.

  12. The impact of changes in source water quality on trihalomethane and haloacetonitrile formation in chlorinated drinking water.

    Science.gov (United States)

    Xue, Chonghua; Wang, Qi; Chu, Wenhai; Templeton, Michael R

    2014-12-01

    This study examined the formation of disinfection by-products (DBPs), including nitrogenous DBPs, haloacetonitriles (HANs), and carbonaceous DBPs, trihalomethanes (THMs), upon chlorination of water samples collected from a conventional Chinese surface water treatment plant (i.e. applying coagulation, sedimentation, and filtration). Reductions in the average concentrations (and range, shown in brackets) of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) from 4.8 (3.0-7.3) μg/L and 0.52 (0.20-0.81) μg/L in 2010 to 2.4 (1.4-3.7) μg/L and 0.17 (0.11-0.31) μg/L in 2012, respectively, led to a decrease in HANs and THMs from 5.3 and 28.5 μg/L initially to 0.85 and 8.2 μg/L, as average concentrations, respectively. The bromide concentration in the source water also decreased from 2010 to 2012, but the bromine incorporation factor (BIF) for the THMs did not change significantly; however, for HAN the BIFs increased because the reduction in DON was higher than that of bromide. There was good linear relationship between DOC and THM concentrations, but not between DON and HANs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. MPEG-4 interactive image transmission on mobile thin clients

    Science.gov (United States)

    Joveski, B.; Mitrea, M.; Pr"teux, F.

    2010-05-01

    The main issue in this paper is to deploy a compressing algorithm for heterogeneous content (text, graphics, image and video) with low-complex decoding. Such an algorithm will be involved in the remote display core problem for mobile thin clients: it allows the graphical content, computed on a remote server, to be displayer on the user's thin terminal, even when the network constraints (bandwidth, errors) are very strict. The paper is structured into three parts. First, a client-server architecture is presented. On the server side, the graphical content is parsed, converted and binary encoded into the MPEG 4 (BiFS, LASeR) format. This content is further streamed to the terminal, where it is played into a simple MPEG player. Secondly, this architecture is considered as a test bed for MPEG 4 performance assessment for various types of content (image, graphics, text). The quantitative results were focussed on bandwidth requirements and quality of experience. Finally, the conclusions are structured as a reference benchmarking of the MPEG (BiFS, LASeR) and outside (VNC) mobile remote display potential solutions.

  14. A case study on the impact of variable emission rates on the calculated MEI

    Energy Technology Data Exchange (ETDEWEB)

    Perry, R.A.; Chadbourne, J.

    1994-12-31

    When regulatory agencies require dispersion modeling to evaluate air quality impacts, the emissions modeled are the maximum allowable emissions. This requires an assumption that the source will constantly emit the maximum amount of each contaminant allowed by rule or by permit condition. For most sources, the actual emissions are typically much lower than the maximum allowed. Some years ago the Agency considered this issue through the ExEx policy to provide for specified {open_quotes}expected exceedances{close_quotes} while still meeting ambient standards. Emissions of Resource Conservation and Recovery Act (RCRA) metals from a cement kiln, using hazardous waste to replace fossil fuels, provides a useful example of the effect of variable emissions. The Boiler and Industrial Furnace (BIF) rule at 40 C.F.R. 266 subpart H specifies that allowable emission of arsenic, beryllium, cadmium, chromium, lead and thallium inter alia can be determined through dispersion modeling. Section 266.103(b)(v) specifies that the location of the most exposed individual (MEI) and dilution faction ({mu}g/m{sup 3} / g/sec) for the maximum annual average value must be determined. In addition, risk specific doses and reference air concentration (RSDs and RACs in {mu}g/m{sup 3}) are published in BIF appendix IV and V based on 70 years of exposure.

  15. Partition of proteins in aqueous two-phase systems based on Cashew-nut tree gum and poly(ethylene glycol

    Directory of Open Access Journals (Sweden)

    Leonie Asfora Sarubbo

    2004-09-01

    Full Text Available The partitioning of two proteins, bovine serum albumin (BSA and trypsin was studied in an aqueous poly(ethylene glycol(PEG- Cashew-nut tree gum system. The phase diagram was provided for Cashew-nut tree gum and PEG molecular weight of 1500 at two different temperatures. The influence of several parameters including concentrations of polymers, pH, salt addition and temperature on the partitioning of these proteins were investigated.. The results of this research demonstrated the importance of the protein characteristics for partitioning in aqueous biphasic system.A partição de duas proteínas, albumina de soro bovino (BSA e tripsina foi estudada no sistema bifásico aquoso Polietileno glicol(PEG - Goma do cajueiro. O diagrama de fases foi estabelecido para a Goma do Cajueiro e para PEG de peso molecular 1500 em duas diferentes temperaturas. A influência de vários parâmetros na partição destas proteínas, incluindo concentração dos polímeros, pH, adição de sal e temperatura foi investigada. Os resultados desta pesquisa demonstraram a importância das características da proteína na partição em sistemas bifásicos aquosos.

  16. Efecto terapéutico del extracto etanólico de Erythroxylum coca spp. en anemia ferropénica inducida en ratas Holtzman macho

    Directory of Open Access Journals (Sweden)

    Evelyn F. Gonzales-Carazas

    2013-01-01

    Full Text Available Introducción: La hoja de coca ha sido usada tradicionalmente con fines medicinales y contiene altos niveles de hierro. Objetivos: Determinar el efecto del extracto etanólico de Erythroxylum coca spp. frente a anemia ferropénica inducida por dieta deficiente en hierro, en ratas Holtzman macho. Diseño: Experimental. Lugar: Laboratorio del Instituto de Patología, Facultad de Medicina, Universidad Nacional Mayor de San Marcos. Material biológico: Dieciocho ratas Holtzman macho de 16 días de edad recién destetadas. Intervenciones: Se formó tres grupos de seis ratas cada uno: a grupo hierro suficiente (HS, recibió 25 g/d de alimento balanceado durante 7 semanas; b grupo hierro deficiente (HD, recibió 25 g/d de dieta ferropénica durante 7 semanas; y, c el grupo hierro deficiente - extracto E. coca (HD-EC, recibió 25 g/d de dieta ferropénica durante 7 semanas y a partir de la semana 5 se agregó 18 g/d de extracto de E. coca. Principales medidas de resultados: Nivel sérico de hemoglobina, peso y talla. Resultados: Al finalizar el tratamiento, se observó aumento significativo de la hemoglobina en el grupo HD-EC (p=0,04. Se encontró diferencia significativa en los niveles séricos de hemoglobina entre los grupos HD-EC y HD (p=0,0062. No se encontró diferencia significativa en los valores de hemoglobina entre los grupos HD-EC y HS (p= 0,06. No se evidenció diferencia en el peso y la talla entre los grupos HD y HD-EC (p=0,20 y p=0,23, respectivamente. Conclusiones: E. coca presenta efecto antianémico experimental, sustentado en los resultados de los niveles de hemoglobina.

  17. Testing Timescales for Rhythms Recorded in the 2.5 Ga Banded Iron Formation of the Dales Gorge Member (Brockman Iron Formation, Hamersley Group, Australia)

    Science.gov (United States)

    Hinnov, L. A.; de Oliveira Carvalho Rodrigues, P.; Franco, D.

    2017-12-01

    The classic, Superior-type banded iron formation (BIF) of the Precambrian Dales Gorge Member (DGM) of the Brockman Iron Formation, Hamersley Basin, Western Australia consists of a succession of micro- (millimeter-scale) and meso- (centimeter to decimeter-scale) bands of primarily iron-silica chemical sediment alternations, separated into macro- (meter to decameter-scale) bands by shales (1). Here, we present a time-frequency analysis of a gray-scale scan of the DGM "type section core" Hole 47A with small contributions from Hole EC10 (1) to provide a comprehensive characterization of banding patterns and periodicity throughout the 140 m section. SHRIMP zircon ages (2) indicate that the DGM was deposited over approximately 30 myr during the Archean-Proterozoic transition just prior to the Great Oxidation Event. This suggests that the banding patterns recorded Milankovitch cycles, although with orbital-rotational parameters significantly different from present-day due to Earth's tidal dissipation and chaotic episodes in the Solar System since 2.5 Ga. Banding patterns change systematically within the formation in response to slowly varying environmental conditions, which have been interpreted previously to be related to sea level change and basin evolution (3). Researchers, including (2), have questioned the 30 myr duration, suggesting instead that the micro-bands may be annual in scale. This would indicate a much shorter duration of less than 150 kyr for the DGM. In an attempt to determine whether Milankovitch cycles could have generated the meso-band patterns, we present detailed studies of BIF0 and BIF12, which typify the marked changes in meso-banding along the section. Objective procedures are also applied, including ASM (4) and TIMEOPT (5) to test for a range of potential alternative timescales assuming orbital-rotational parameter values modeled for 2.5 Ga. References: (1) Trendall, A.K., Blockley, J.G., GSWA Ann. Rep. 1967, 48, 1968; (2) Trendall, A.K., et al

  18. Heart failure in patients with kidney disease and iron deficiency: The role of iron therapy

    Directory of Open Access Journals (Sweden)

    Aleix Cases Amenós

    2017-11-01

    Full Text Available Chronic kidney disease and anaemia are common in heart failure (HF and are associated with a worse prognosis in these patients. Iron deficiency is also common in patients with HF and increases the risk of morbidity and mortality, regardless of the presence or absence of anaemia. While the treatment of anaemia with erythropoiesis-stimulating agents in patients with HF have failed to show a benefit in terms of morbidity and mortality, treatment with IV iron in patients with HF and reduced ejection fraction and iron deficiency is associated with clinical improvement. In a post hoc analysis of a clinical trial, iron therapy improved kidney function in patients with HF and iron deficiency. In fact, the European Society of Cardiology's recent clinical guidelines on HF suggest that in symptomatic patients with reduced ejection fraction and iron deficiency, treatment with IV ferric carboxymaltose should be considered to improve symptoms, the ability to exercise and quality of life. Iron plays a key role in oxygen storage (myoglobin and in energy metabolism, and there are pathophysiological bases that explain the beneficial effect of IV iron therapy in patients with HF. All these aspects are reviewed in this article. Resumen: La enfermedad renal crónica y la anemia son frecuentes en la insuficiencia cardíaca (IC y su presencia se asocia con un peor pronóstico en estos pacientes. La ferropenia es frecuente en pacientes con IC y aumenta el riesgo de morbimortalidad, independientemente de la presencia o no de anemia. Mientras el tratamiento de la anemia con agentes estimuladores de la eritropoyesis en pacientes con IC no ha demostrado un beneficio sobre la morbimortalidad, el tratamiento con hierro intravenoso (iv en pacientes con IC y fracción de eyección disminuida y déficit de hierro se asocia con una mejoría clínica. Además, en un análisis post hoc de un ensayo clínico, la ferroterapia mejoró la función renal en pacientes con IC y

  19. Evaluación de la reducción de pelets utilizando carbón como agente reductor

    Directory of Open Access Journals (Sweden)

    Sandra Patricia Pérez Velásquez Alfonso López Díaz

    2010-11-01

    Full Text Available La obtención del acero se realiza a partir del mineralde hierro o de  la chatarra. En el primer caso el procesotiene lugar vía alto horno–convertidor; en el segundo,vía horno  eléctrico de  arco. Sin  embargo,  al hornoeléctrico también se pueden cargar los denominadospelets  prerreducidos  de  minerales  de  hierro,materiales metálicos  que  pueden  ser  obtenidos  apartir de  finos de mineral de hierro  (portador de  lacarga metálica,  finos de  carbón  (agente  reductor,finos  de  cal  (agente  desulfurante  y  bentonita(aglomerante, los cuales son convertidos en ovoidesmediante el empleo de un disco peletizador. El trabajomuestra  la  caracterización  realizada  a  las materiasprimas,  los  ensayos  de  reducibilidad  efectuados  apelets cargados en un horno tipo Linder –fabricadosa partir de dos yacimientos colombianos de mineralesde  hierro–  y  el  diseño  y  construcción  de  un  hornopara evaluar el comportamiento de los pelets durantela  reducción. Describe  los  equipos  y  analiza  sus

  20. Overview of the nutritional status of selected micronutrients in Mexican children in 2006 Estado nutricional de algunos micronutrientes en niños mexicanos en 2006

    Directory of Open Access Journals (Sweden)

    Teresa Shamah-Levy

    2012-04-01

    Full Text Available OBJETIVE: To present an overview of micronutrient status of Mexican children in 2006. MATERIALS AND METHODS: Data on iron, zinc, folate and vitamin B12 deficiencies and low serum copper and magnesium were gathered and critically analyzed from the 2006 National Health and Nutrition Survey. RESULTS: Iron deficiency is still the main nutritional deficiency in children (13%-26%. Zinc deficiency was high in all age groups (≈25% but reduced 5.6 PP in children OBJETIVO: Presentar un panorama del estado de micronutrimentos de niños mexicanos en 2006. MATERIAL Y MÉTODOS: Los datos sobre deficiencias de hierro, zinc, folatos, vitamina B12 y concentraciones bajas de cobre y magnesio se analizaron a partir de la Encuesta Nacional de Salud y Nutrición 2006. RESULTADOS: La deficiencia de hierro fue la más importante en niños (13-26%. La deficiencia de zinc fue alta en todos los grupos de edad (≈25% y disminuyó entre 1999 y 2006 5.6 pp en niños. La deficiencia de folatos fue de 3.2% y la de vitamina B12 de 7.7%. Las concentraciones bajas de magnesio y cobre fueron altas (22.6 y 30.6%, respectivamente. CONCLUSIONES: La deficiencia de hierro pareció disminuir y la de zinc se redujo en niños mexicanos. La alta prevalencia de deficiencias de cobre y magnesio merecen más investigación para entender sus implicaciones en salud pública.

  1. Evaluación de la educación nutricional y un suplemento para prevenir la anemia durante la gestación.

    Directory of Open Access Journals (Sweden)

    Beatriz Elena Parra

    2005-06-01

    Full Text Available Introducción. Las deficiencias de hierro y acido fólico son la causa de graves problemas de salud en la mujer gestante y en el niño, con implicaciones negativas para el desarrollo económico y social de los países. Objetivos. Evaluar los cambios de conocimientos sobre funciones, alimentos fuentes y biodisponibilidad del hierro y folatos, el consumo y la tolerancia de un suplemento y el comportamiento de los índices globulares en gestantes del programa prenatal de la Empresa Social del Estado Hospital Gilberto Mejía Mejía de Rionegro, Antioquia, Colombia, entre abril de 2002 y abril de 2003. Materiales y métodos. Estudio cuasi experimental en una muestra de 42 madres, seleccionada por conveniencia, con una confianza del 95%. La intervención fue un programa de educación nutricional y el suministro de un suplemento con 60 mg de hierro elemental, 400 J.g de acido fólico y 70 mg de vitamina C, elaborado para la investigación por el Laboratorio Profesional Farmacéutico, LAPROFF. El efecto de la intervención se midió en los cambios de conocimientos relacionados con las practicas que modifican la biodisponibilidad y el consumo de alimentos fuentes de estos nutrientes, en la tolerancia y la adherencia al suplemento y en la modificación de variables hematológicas: hemoglobina, hematocrito y ferritina. Resultados. Hubo cambios positivos de conocimientos sobre cómo mejorar las practicas alimentarias y la ingestión del suplemento; el 94,4% de las participantes no presentó anemia al finalizar la gestación. Conclusión. Estos resultados concuerdan con otros provenientes de poblaciones similares; se justifica implementar esta estrategia integrada en los programas de control prenatal de Colombia.

  2. PROPIEDADES QUÍMICAS DE UN LUVISOL DESPUÉS DE LA CONVERSIÓN DEL BOSQUE A LA AGRICULTURA EN CAMPECHE, MÉXICO

    Directory of Open Access Journals (Sweden)

    Juan Medina-M\\u00E9ndez

    2009-01-01

    Full Text Available El objetivo de este trabajo fue evaluar los cambios en las propiedades químicas de un suelo Luvisol en Campeche, México en un período de 30 años (1974 al 2003. Los principales cultivos en el área de estudio fueron el maíz bajo temporal y mango bajo riego. Con fines de comparación también se consideró como punto de referencia al suelo con vegetación natural de selva. En el maíz, se observaron disminuciones con el tiempo en el pH, conductividad eléctrica, materia orgánica y calcio intercambiable; ocurrió todo lo contrario en el mango. En el maíz, el fósforo, potasio, sodio, hierro y cobre presentaron una tendencia a disminuir, pero posteriormente se incrementaron a un valor superior al que presentó el suelo de vegetación natural; mientras que en el mango, este comportamiento solo se observó en el cobre, hierro y zinc. Los cationes intercambiables, calcio, potasio, magnesio y sodio, al igual que el manganeso, presentaron valores inferiores en los huertos de mango 30 años de edad, comparados con el suelo de vegetación natural. En el maíz, el fósforo, magnesio, potasio, hierro, manganeso, cobre y zinc, presentaron un valor superior al del suelo con vegetación natural, en el estrato de uno a cinco años, relacionado con el desmonte del terreno, la "quema" de la vegetación y la labranza; pero a excepción del zinc, el valor alcanzado por éstos disminuyó a partir de los siguientes cinco años.

  3. Tratamiento y gestión de baños ácidos de decapado

    OpenAIRE

    Domínguez Hernández, Elena

    2012-01-01

    El objetivo del presente proyecto es describir y dimensionar una planta de tratamiento físico-químico de residuos ácidos procedentes de baños agotados de decapado. El decapado es un procedimiento industrial para eliminar la capa superficial de óxidos de hierro, la calamina (carbonato de zinc natural) y partículas metálicas de la superficie del metal base Departamento de Ingeniería Química y Tecnología del Medio Ambiente Ingeniero Técnico Industrial, Especialidad en Química I...

  4. The Foreign Policy of Venezuela Toward El Salvador: 1979-1983

    Science.gov (United States)

    1990-06-01

    vista extra-regional, la "zona vital" es rica en materiales estrat~gicos, tales como el petr6leo, el hierro, y el aluminlo. Adem~s del petr6leo de...nivel de post-grado, en el Area de hidrocarburos para el periodo 1981 / 1982. Ofrecimiento de cooperaci6n en el campo de geologia de uranlo y materiales ...hombre, yo lo conocia, aparte de que era un homnbre muy preparado, muy inteligente , era un fan~tico. *Un fanatico religioso. Yo s6 porque lo digo

  5. Plan de emergencia interior de una instalación tipo para tratamiento de agua potable

    OpenAIRE

    Martínez Segura, Alfonso

    2015-01-01

    El objetivo evidente de una ETAP es la de conseguir de manera constante la producción de agua de consumo de la mejor calidad y a un coste técnico y económico razonable. Como más relevantes, las características fundamentales que deben modificarse de un agua bruta para conseguir su potabilización son: color, turbidez, concentraciones originales de hierro, manganeso, amonio, nitritos, y materia orgánica, así como, inexcusablemente, supresión de la flora microbiana. Una estación po...

  6. Bioactividad intrínseca de nanopartículas magnéticas recubiertas con poli-etilénimina sobre células tumorales pancreáticas y del sistema fagocítico mononuclear

    OpenAIRE

    Mulens-Arias, Vladimir

    2015-01-01

    Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología Molecular. Fecha de lectura: 12-06-2015 La nanotecnología ha significado un considerable salto para aplicaciones biomédicas, debido a las propiedades químico‐ físicas intrínsecas de los biomateriales, y a la posibilidad de modificarlos de acuerdo a los intereses terapéuticos y diagnósticos específicos. Particularmente, las nanopartículas superparamagnéticas de óxido de hierro (...

  7. Síntesis de dendrímeros con sistemas -conjugados ferrocenílicos y resorcinarenos como moléculas centrales

    OpenAIRE

    Reyes Valderrama, María Isabel

    2007-01-01

    A inicios de los años cincuenta, la síntesis y caracterización de una nueva molécula denominada ferroceno (diciclopentadienilhierro) despertó el interés de la comunidad científica en el campo de la química organometálica. El ferroceno posee una estructura formada por dos anillos ciclopentadienilos unidos paralelamente a través de un átomo de hierro como si fuera un sandwich. Sin duda alguna, la importancia del ferroceno y sus derivados reside en la gran cantidad de aplicaciones que poseen. S...

  8. Microwave digestion for determination of iron and zinc content of total food

    OpenAIRE

    Silva-Trejos, Paulina

    2012-01-01

    En el presente estudio se optimizó el procedimiento de digestión de alimentos por medio de un horno de microondas, para cuantificar el hierro y el zinc totales en diferentes matrices por espectroscopía de absorción atómica. Se analizó la cantidad óptima de HNO3 concentrado al 65% para digerir determinada masa de muestra por evaluación del porcentaje de recuperación obtenido con diferente cantidad de HNO3. Los resultados no difieren de los obtenidos por los métodos recomendados oficialmente de...

  9. Diagnóstico de pica durante el embarazo y deficiencia de micronutrientes en mujeres argentinas Pica diagnosis during pregnancy and micronutrient dificiency in Argentine women

    OpenAIRE

    M. S. Poy; A. Weisstaub; C. Iglesias; S. Fernández; M.ª L. Portela; L. B. López

    2012-01-01

    Objetivo: Evaluar mediante indicadores bioquímicos el estado nutricional del hierro y el zinc en mujeres con y sin diagnóstico de pica durante el embarazo. Metodología: Se seleccionaron 109 puérperas del Hospital Fiorito, Argentina. El diagnostico de pica se realizó en 42 de ellas, en tanto que 67 mujeres no refirieron el hábito. Mediante un contador hematológico se determinaron los valores de hemoglobina, volumen corpuscular medio, hemoglobina corpuscular media, concentración de hemoglobina ...

  10. Optimización de un nuevo proceso electroquímico para descontaminación de residuos finos de escombrera de mina

    OpenAIRE

    Nogueira Henriques-Rosa, Manuel Alberto

    2016-01-01

    [ES]La falta de un proceso de descontaminación de residuos de escombreras de mina fue el problema a superar en este trabajo conducente a la obtención del título de doctor. Los estudios iniciales se basaron en la caracterización física y química de los residuos de la mina de wolframio de Barruecopardo (provincia de Salamanca) y sirvieron como base para el posterior estudio sobre la eliminación del arsénico, el hierro y el manganeso presentes en esos residuos aplicando el nuevo método de tr...

  11. Cirrosis hepática

    Directory of Open Access Journals (Sweden)

    Alberto Albornoz Plata

    1956-03-01

    Full Text Available De Kirrhos que significa color amarillo naranja que es el color más frecuente de los hígados cirróticos y debido al depósito del hierro en el tejido conectivo. No tiene ninguna relación con scirrhus, pero generalmente se interpreta cirrosis como sinónimo de duro. Toda enfermedad crónica hepática termina en cirrosis. Es esencialmente una enfermedad histológica de la célula hepática y no del tejido conjuntivo.

  12. Ukola Club. Bar americano

    Directory of Open Access Journals (Sweden)

    Azpiazu, J. R.

    1961-03-01

    Full Text Available En la calle de Serrano, aprovechando un semisótano dedicado a otro negocio anteriormente, se ha instalado un bar americano, de cuyo interior ofrecemos algunos pormenores. Se han cuidado, especialmente, las condiciones acústicas, resueltas por medio de un techo de escayola perforada, con vitrofib en su parte superior, y paredes de madera, que contribuyen a darle un ambiente cálido y acogedor. El soporte de hierro laminado existente en el centro del local, cuya supresión hubiera sido costosa, se ha revestido con lajas de mármol que le convierten en un elemento decorativo.

  13. Prevalencia de la anemia ferropénica en mujeres embarazadas

    OpenAIRE

    Sánchez Salazar, Francisca Rosa; Castanedo Valdés, Raquel; Trelles Aguabella, Edilia; Pedroso Hernández, Patricia; Lugones Botell, Miguel

    2001-01-01

    Con el objetivo de identificar la prevalencia de la anemia por deficiencia de hierro, se estudió en la consulta de nutrición del Hospital Docente Ginecoobstétrico "Eusebio Hernández", desde enero de 1993 a diciembre de 1999 a 11 904 gestantes; de ellas 5 169 eran portadoras de anemia ferropénica. La prevalencia alcanzó el 43,1 % y el grupo de edad más vulnerable fue el de 20 a 24 años. Las gestantes con bajo peso preconcepcional y las comprendidas entre las 14 y 23 semanas de gestación fueron...

  14. Anemia en el embarazo, un problema de salud que puede prevenirse

    OpenAIRE

    Espitia De La Hoz, Franklin; Orozco Santiago, Lilian

    2013-01-01

    Introducción: la anemia es el trastorno nutricional más frecuente en el mundo, y debido a que en el embarazo existe una gran demanda de hierro, se constituye en un importante riesgo de desarrollar anemia ferropénica. La anemia es la alteración hematológica más diagnosticada durante la gestación, por lo que todas las gestantes están en riesgo de padecer anemia en el embarazo, siendo más frecuente en países subdesarrollados. Es referida como un proceso dilucional secundario al aumento del volum...

  15. Contribución al patrón alimenticio y de actividad de las poblaciones del Norte peninsular. Fuentenegroso, Asturias

    OpenAIRE

    Barroso Bernejo, Rosa; Camino Mayor, Jorge; De Balbín Behrmann, Rodrigo; Bueno Ramírez, Primitiva; Trancho Gayo, Gonzalo; Robledo Sanz, B.

    2008-01-01

    En este artículo se recogen los indicadores de actividad y paleodieta de único enterramiento del Bronce Final - Hierro conocido en Asturias contrastándolos con datos antropológicos de poblaciones cercanas y los registros paleobotánicos obtenidos en los castros ocupados durante el mismo momento. Como en la chica de Fuentenegroso, se repiten las huellas de esfuerzos físicos de carga, y los datos de los últimos años obtenidos en los poblados abogan por una alimentación variada de fuerte componen...

  16. Contenido nutricional, propiedades funcionales y conservación de flores comestibles: Revisión

    OpenAIRE

    Lara-Cortés, Estrella; Osorio-Díaz, Perla; Jiménez-Aparicio, Antonio; Bautista-Baños, Silvia

    2013-01-01

    La florifagia, que es el consumo de flores como alimento es una práctica que, aunque no es nueva no estaba muy difundida entre los consumidores hasta hace algunas décadas. Las flores comestibles contribuyen al mejoramiento de la estética de los alimentos además, aportan sustancias biológicamente activas como vitaminas A, C, riboflavina, niacina, minerales como calcio, fósforo, hierro y potasio beneficiando la salud de quien las consume. Esta revisión incluye algunos ejemplos de flores comesti...

  17. Cadmio: efectos sobre la salud. Respuesta celular y molecular

    OpenAIRE

    Martínez Flores, Karina; Souza Arroyo, Verónica; Bucio Ortiz, Leticia; Gómez Quiroz, Luis Enrique; Gutiérrez Ruiz, María Concepción

    2013-01-01

    El cadmio (Cd) es un metal que se encuentra principalmente en la corteza terrestre y siempre se presenta en combinación con el zinc. Es ampliamente utilizado en la industria. Se considera un contaminante y es liberado al ambiente como subproducto de la extracción de cobre, hierro y zinc. La exposición al Cd puede producir una variedad de efectos adversos tanto en el humano como en los animales. Una vez absorbido se acumula en el organismo por tiempos largos. Dependiendo de la dosis, fuente y ...

  18. Influencia del estatus de cobre sobre la acumulación de metales tóxicos y esenciales en ganado vacuno

    OpenAIRE

    I Blanco Penedo; JM Cruz; M López-Alonso; M Miranda; C Castillo; J Hernández; JL Benedito

    2005-01-01

    La interacción entre elementos tóxicos y esenciales, así como de elementos esenciales entre sí, condiciona tanto la acumulación de estos elementos en el organismo como sus efectos nocivos. En este estudio se evaluaron las correlaciones entre los niveles de cobre y los elementos tóxicos (cadmio, plomo) y esenciales (molibdeno, hierro, selenio, zinc, manganeso y cobalto) en dos tejidos (hígado y riñón) de 195 terneros procedentes de la comarca del Deza (NO de España), una z...

  19. Catalizadores Fe/SiO2 para la oxidación selectiva de metano hasta formaldehido

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Guerrero Fajardo

    2006-05-01

    Full Text Available La oxidación selectiva de metano a formaldehido fue analizada con catalizadores de hierro soportados sobre sílice preparados por el método sol-gel, el cual permite obtener gran área superficial del soporte facilitando una alta dispersión del hierro sobre la matriz amorfa de la sílice. Se prepararon siete (7 catalizadores, uno de ellos correspondiente al soporte de sIlice, otros cinco (5 con cargas de hierro entre 0,1-0,5 % en peso. El catalizador No. 7 (0,5% Fe en peso se prepara con control de pH neutro y resultó de características más homogéneas ya que no se presentaron especies aisladas de hierro, corroborado por análisis SEM y TEM. Las áreas BET mayores son del orden de 1 757 y 993 m2.g-1 para los catalizadores de 0,5% Fe, con porcentajes promedio del 36% de microporosidad y 43% de mesoporosidad. La difracción de rayos X confirma la estructura amorfa del catalizador. La actividad catalítica es realizada con el catalizador No. 7 a presión atmosférica en reactor de cuarzo, mezcla de reacción CH / 0 /N =7.5/1/4, intervalo de temperatura 400-750°C. Los productos de reacción son analizados por cromatografía 2 2 de gases con TCD. Los catalizadores heterogéneos presentan mayor conversión de metano pero con selectividad al metanol, mientras que el catalizador homogéneo No. 7 da mejores resultados en formaldehido. Para el catalizador 7, el porcentaje más alto de conversión (8,60 mol% se presenta a 650°C. La selectividad al formaldehido está en 50 mol% entre 600-650°C y en este intervalo se encuentra el máximo rendimiento (0,31 g HCH0/kg catalizador,considerando así que la temperatura de operación es de 650°C.

  20. INDUSTRIA, EMISIONES GASEOSAS Y GESTIÓN AMBIENTAL URBANA Diagnóstico de las condiciones operativas de las fundiciones en Tandil, Argentina

    Directory of Open Access Journals (Sweden)

    Beatriz Soledad Sosa

    2013-06-01

    Full Text Available De las problemáticas ambientales urbanas, las asociadas a la industria presentan especial interés para la gestión ambiental. La ciudad de Tandil en Argentina, debe su crecimiento económico y urbano a la actividad metalmecánica, -en particular a la fundición-, y a pesar de las crisis del sector, la actividad sigue siendo eje de crecimiento económico y urbano local. Esta investigación caracteriza -en términos productivos, operativos y ambientales- las industrias de fundición y evalúa las condiciones operativas de la gestión de emisiones gaseosas en el sector en el año 2010. Fue posible analizar unas 25 industrias sobre 30. La muestra fue representativa de los cinco procesos productivos identificados: aluminio (Al, aluminio/hierro (Al Fe, aluminio/bronce (Al Cu+Sn, aluminio/hierro/bronce (Al Fe Cu+Sn, hierro (Fe. Las variables analizadas fueron: materia prima de fusión, horno utilizado y, tamaño de la industria. Para la obtención de los datos de producción se aplicaron entrevistas estructuradas, y para determinar el tamaño de la industria  se usaron encuestas. Fue posible describir la situación productiva del sector a nivel local: La mayoría de las industrias destinan su producción al sector automotriz. Evaluando la relación tamaño y tipo de empresa, las fundiciones de Aluminio son pequeñas. En relación al hierro, están representados los tres tamaños empresariales posibles y existe una industria mediana que ocupa entre 51 y 230 empleados. Las condiciones operativas y de cumplimiento de la legislación en el control de los efluentes gaseosos analizados demandan identificar indicadores de seguimiento para la etapa de fusión del proceso para conocer con precisión los contaminantes resultantes y sus efectos ambientales.