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Sample records for rangos sr research

  1. Desigualdades rango lineales en 5 variables

    OpenAIRE

    Campos Maldonado, Luis Andrés

    2013-01-01

    En este trabajo se hace un estudio de las desigualdades rango lineales, encontradas por R. Dougherty, C. Freiling y K. Zeger, las cuales involucran 5 variables, ´estas, junto a las desigualdades polimatroides y de Ingleton verifican que, las funciones rango lineales en 5 variables determinan un cono convexo poli´edrico. Adem´as, se estudia la caracterizaci´on de estas funciones involucrando hasta 4 variables, donde solo las desigualdades polimatroides y de Ingleton, logran cara...

  2. Strontium isotopes (87Sr/86Sr) in terrestrial ecological and palaeoecological research: empirical efforts and recent advances in continental-scale models.

    Science.gov (United States)

    Crowley, Brooke E; Miller, Joshua H; Bataille, Clément P

    2017-02-01

    Strontium (Sr) isotope analysis can provide detailed biogeographical and ecological information about modern and ancient organisms. Because Sr isotope ratios ( 87 Sr/ 86 Sr) in biologically relevant materials such as water, soil, vegetation, and animal tissues predominantly reflect local geology, they can be used to distinguish geologically distinct regions as well as identify highly mobile individuals or populations. While the application of Sr isotope analysis to biological research has been steadily increasing, high analytical costs have prohibited more widespread use. Additionally, accessibility of this geochemical tool has been hampered due to limited understanding of (i) the degree to which biologically relevant materials differ in their spatial averaging of 87 Sr/ 86 Sr ratios, and (ii) how these differences may be affected by lithologic complexity. A recently developed continental-scale model that accounts for variability in bedrock weathering rates and predicts Sr isotope ratios of surface water could help resolve these questions. In addition, if this 'local water' model can accurately predict 87 Sr/ 86 Sr ratios for other biologically relevant materials, there would be reduced need for researchers to assess regional Sr isotope patterns empirically. Here, we compile 87 Sr/ 86 Sr data for surface water, soil, vegetation, and mammalian and fish skeletal tissues from the literature and compare the accuracy with which the local water model predicts Sr isotope data among these five materials across the contiguous USA. We find that measured Sr isotope ratios for all five materials are generally close to those predicted by the local water model, although not with uniform accuracy. Mammal skeletal tissues are most accurately predicted, particularly in regions with low variability in 87 Sr/ 86 Sr predicted by the local water model. Increasing regional geologic heterogeneity increases both the offset and variance between modelled and empirical Sr isotope ratios, but

  3. <Research Report>New superconductor: the antiperovskite oxide Sr(3-x)SnO

    OpenAIRE

    米澤, 進吾

    2017-01-01

    The antiperovskite (inverse perovskite) oxides are charge-inverted analogues of the ordinary perovskite oxides. In this article, we explain our recent discovery of superconductivity in Sr(3-x)SnO, the first superconductor among the antiperovskite oxides. The pristine compound without Sr deficiency is a candidate of the Dirac semimetal. We found that the Sr-deficient compound exhibits superconductivity with the critical temperature of around 5 K, due to doped hole carriers. Theoretically, it i...

  4. Liderazgo de rango total y gestión del conocimiento: situación actual y perspectivas de desarrollo

    OpenAIRE

    Burbano Botero, Nathalia; Samaca, Hugo Alejandro

    2016-01-01

    El presente trabajo muestra los tipos de liderazgo de rango total y su relación con respecto a la gestión del conocimiento. Para ello, en primer lugar, se efectúa la investigación teórica del liderazgo transaccional y del liderazgo transformacional, ya que estos hacen parte del liderazgo de rango total, de igual forma se estudiará los aspectos primordiales de la gestión del conocimiento, dando cavidad al análisis de la relación entre dichos conceptos y cómo influyen en la perdurabilidad de la...

  5. Modelo de resiliencia sexual en el adolescente: teoría de rango medio

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    Lubia Castillo-Arcos

    2012-01-01

    Full Text Available Para el profesional de enfermería es indispensable contar con teorías propias que le ayuden a sustentar científicamente el cuidado, haciendo de esta forma una práctica disciplinar más autónoma y segura. El presente trabajo tuvo como objetivo generar una teoría de rango medio para dar explicación al fenómeno de la conducta sexual de riesgo en el adolescente. Se utilizó el método de derivación teórica de Fawcett para realizar la estructuración conceptual-teórica-empírica de la teoría propuesta. La revisión de la literatura permitió realizar la estructura del Modelo de resiliencia sexual en el adolescente a partir de los conceptos y las proposiciones que integran los factores de riesgo, factores protectores y factor resultado que influyen en la resiliencia durante la etapa de desarrollo del adolescente. Asimismo, el modelo contribuye al diseño de intervenciones psicoeducativas dirigidas a la prevención de conductas sexuales de riesgo para VIH.

  6. EFECTO DEL ESTIRAMIENTO ACTIVO SOBRE EL RANGO DE MOVIMIENTO DE LA FLEXIÓN DE CADERA: 15 VERSUS 30 SEGUNDOS

    OpenAIRE

    F. Ayala; P. Sainz de Baranda

    2010-01-01

     

    RESUMEN

    El objetivo principal de este estudio fue valorar la eficacia de un programa de estiramientos activos con una duración de 12 semanas para aumentar el rango de movimiento de la flexión de cadera en adultos jóvenes, así como comparar la eficacia de dos durac...

  7. Modelo de rol materno en la alimentación del lactante: Teoría del rango medio

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    Rosario Edith Ortiz-Félix

    Full Text Available Las interacciones madre-hijo durante la alimentación en el primer año de vida tienen impacto duradero en la regulación del apetito y el desarrollo de obesidad actual y futura del individuo. Para los profesionales de enfermería es un reto y una nueva función prevenir problemas nutricionales en los lactantes. Contar con teorías de rango medio propias de enfermería que guíen el cuidado diario resulta indispensable. El presente trabajo presenta el desarrollo de la teoría de rango medio Modelo de rol materno en la alimentación del lactante, mediante el método de derivación teórica de Fawcett. Este modelo tiene como objetivo explicar cómo características maternas y del lactante influyen en el rol materno de alimentación y estado nutricional del hijo en el primer año de vida. Mediante este modelo se ofrece sustento teórico para la investigación e intervenciones de enfermería enfocadas a prevenir problemas de nutrición en el lactante.

  8. Research Update: Conductivity and beyond at the LaAlO3/SrTiO3 interface

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    S. Gariglio

    2016-06-01

    Full Text Available In this review, we focus on the celebrated interface between two band insulators, LaAlO3 and SrTiO3, that was found to be conducting, superconducting, and to display a strong spin-orbit coupling. We discuss the formation of the 2-dimensional electron liquid at this interface, the particular electronic structure linked to the carrier confinement, the transport properties, and the signatures of magnetism. We then highlight distinctive characteristics of the superconducting regime, such as the electric field effect control of the carrier density, the unique tunability observed in this system, and the role of the electronic subband structure. Finally we compare the behavior of Tc versus 2D doping with the dome-like behavior of the 3D bulk superconductivity observed in doped SrTiO3. This comparison reveals surprising differences when the Tc behavior is analyzed in terms of the 3D carrier density for the interface and the bulk.

  9. Ampliación del rango altitudinal de Marmosa lepida (Thomas, 1888 (Didelphimorphia: Didelphidae en el sureste de Ecuador

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    Brito, Jorge

    2015-12-01

    Full Text Available The Rufous mouse opossum Marmosa lepida is the smallest in the genus Marmosa and one of the least understood and studied. An expedition to the mountains of Kutukú, in southeastern Ecuador, revealed an adult male specimen which was collected while descending from a tree. The information presented here extends the altitudinal range to 1581 meters above sea level at the crest of a ridge in the Kutukú range, and represents the sixth documented locality in Ecuador. The difficulty of trapping and registering some small mammals with conventional methods hinders knowledge of the distribution of many poorly known species and consequently the application of measures for conservation action.La raposa chica radiante Marmosa lepida es el marsupial más pequeño dentro del género y uno de los menos conocidos y estudiados a nivel de historia natural. En una expedición desarrollada a la cordillera de Kutukú al suroriente de Ecuador, se colectó un ejemplar macho adulto mientras descendía de un árbol. La información aquí presentada amplía el rango altitudinal a 1581 msnm en la cresta de la cordillera de Kutukú, y representa la sexta localidad documentada para Ecuador. La dificultad de registro de varios pequeños mamíferos con métodos convencionales dificulta el conocimiento de la distribución de numerosas especies poco conocidas y por ende la aplicación de medidas de acción para la conservación.

  10. Metodología para la obtención del Rango de Trabajo de un transistor como Elemento de Control en una Fuente de Corriente DC

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    Yurany A. Osorno

    2013-01-01

    Full Text Available Se presenta una metodología concebida para el diseño de fuentes de corriente DC, aprovechando las características de los transistores BJT en su región de trabajo lineal (región activa, región que depende de la tensión de codo, la potencia máxima que puede soportar éste y la tensión de polarización; a partir de estos parámetros se identifica el rango de la resistencia de carga que garantiza la corriente constante. La metodología es empleada para implementar un prototipo de fuente de corriente DC de 2A en un rango de resistencia determinado por las características del transistor, garantizando las respectivas restricciones de potencia y temperatura.

  11. Estabilidad de la aleación Cu - 2,5 % Li en el rango 298 a 673 K

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    Ortiz, M.

    2005-10-01

    Full Text Available Contributing to the slight information about the Cu-Li alloys that is nowadays in scientific literature, this work reports the evolution with the temperature of the Cu - 2,5 wt % Li alloy. This alloy is obtained as powder by an electrodeposition process from salts. Powder samples, room temperature compacted tablets and the copper cathodes used in the process are analyzed. The samples were annealed in the rank from 293 to 673 K by different times and then characterized by means of x-rays diffraction. The lithium content was determined by atomic absorption. The analysis of the results shows a decomposition of the alloy as the temperature increases, with a loss of lithium towards the surface of the samples, where this element easily reacts with the atmosphere forming soluble water compounds.

    Contribuyendo a la escasa información que se encuentra actualmente en la literatura científica acerca de las aleaciones Cu-Li, este trabajo informa la evolución de la aleaciónCu-2,5 % Li en peso, en función de la temperatura. La aleación se obtiene en forma de polvo, en un proceso de electrodepósito desde sales fundidas. Se analizan muestras en polvo, pastillas compactadas a temperatura ambiente y los cátodos de cobre utilizados en el proceso. Las muestras son sometidas a tratamientos térmicos en el rango de 293 a 673 K, por diferentes periodos de tiempo y caracterizadas mediante difracción de rayos X y determinación del contenido de litio por absorción atómica. El análisis de los resultados muestra una descomposición de la aleación conforme aumenta la temperatura, con una pérdida de litio hacia la superficie de las muestras, donde este elemento reacciona fácilmente con el ambiente, formando compuestos solubles en agua

  12. The Sr-87/Sr-86 ratio as a powerful tool in forensic investigations

    Science.gov (United States)

    de Muynck, D.; Boyen, S.; Delporte, S.; de Winne, J.; Vanhaecke, F.; Degryse, P.

    2009-04-01

    As a result of the decay of the naturally occurring and long-lived radionuclide Rb-87 into Sr-87, the Sr-87/Sr-86 ratio of a geological material displays geographical variations according to the chemical/mineralogical composition of that material and its geological age. As most part of the strontium, ingested into the human body via the food, is transported to the skeletal tissue, the Sr-87/Sr-86 ratio of an individual's skeletal tissue is a reflection of the geological area in which that individual resided at the moment the skeletal tissue under investigation was formed. Distinct tissues in the human body display a different growth and Sr renewal rate, and hence reflect the place of residence in a distinct period of life (tooth enamel: childhood - tooth dentine and bone tissue: last years of life - nails: last months of life - hair: last weeks of life). Following these considerations, it was investigated if Sr isotope ratio analysis of human hair, nails, bone and dental tissue can be successfully applied in the context of forensic research. Hair, nails, bone and dental tissue of several unidentified persons, currently being investigated by the Disaster Victim Identification unit of the Belgian Federal Police, were available for research. After acid digestion and isolation of the Sr fraction using an extraction chromatographic separation, the Sr-87/Sr-86 ratio of these tissues was determined via multicollector ICP-MS. It was shown that Sr isotope ratio data match traceable facts or information obtained via independent evidence concerning the victim, e.g., by pinpointing his/her area of residence. In this way, it was demonstrated that Sr isotope ratio analysis delivers information that strengthens or weakens arguments concerning a person's identity.

  13. Research on Degradation of Dye Acid Red B by Sr2FeMoO6 Synthesized by Microwave Sintering Method

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    Yong-Qing Zhai

    2012-01-01

    Full Text Available Double perovskite Sr2FeMoO6 was synthesized rapidly by microwave sintering method. The crystal structure of the sample was investigated by XRD. It shows that the as-synthesized sample is Sr2FeMoO6 with tetragonal crystal structure and I4/mmm space group. The test of electrical transport properties shows that the sample exhibits typical semiconductor behavior in the temperature range of 80~300 K. The influence of the dosage of the sample, light irradiation sources, and time on the efficiency of degradation have been studied. The results show Sr2FeMoO6 exhibits excellent degradation activity for dye Acid Red B, the decolorization rate is close to 100% under proper conditions. Meanwhile, a mechanism related to the process of degradation is proposed.

  14. Research on Degradation of Dye Acid Red B by Sr2FeMoO6 Synthesized by Microwave Sintering Method

    OpenAIRE

    Yong-Qing Zhai; Jing Qiao; Man-De Qiu

    2012-01-01

    Double perovskite Sr2FeMoO6 was synthesized rapidly by microwave sintering method. The crystal structure of the sample was investigated by XRD. It shows that the as-synthesized sample is Sr2FeMoO6 with tetragonal crystal structure and I4/mmm space group. The test of electrical transport properties shows that the sample exhibits typical semiconductor behavior in the temperature range of 80~300 K. The influence of the dosage of the sample, light irradiation sources, and time on the efficiency o...

  15. Obtención de bacterias biotransformadoras de carbón de bajo rango a partir de microhábitats con presencia de residuos carbonosos

    OpenAIRE

    Rodríguez, Luz Nidia

    2012-01-01

    Se aislaron bacterias con actividad biotransformadora de carbón de bajo rango (CBR) a partir de muestras ambientales con presencia de residuos de carbón en la mina “El Cerrejón”. Se aislaron 75 morfotipos bacterianos de los cuales 32 presentaron crecimiento en medio sólido mínimo de sales con carbón al 5%. Se diseño un protocolo para la selección de los morfotipos con mayor actividad biotransformadora de CBR, el protocolo incluye el aislamiento en un medio selectivo con CBR en polvo, pruebas ...

  16. Influencia del microhábitat sobre la obtención y actividad de bacterias biotransformadoras de carbón de bajo rango

    OpenAIRE

    Rodríguez Luz Nidia

    2012-01-01

    Se aislaron bacterias con actividad biotransformadora de carbón de bajo rango (CBR) a partir de muestras ambientales con presencia de residuos de carbón en la mina “El Cerrejón”. Se aislaron 75 morfotipos bacterianos de los cuales 32 presentaron crecimiento en medio sólido mínimo de sales con carbón al 5%. Se diseño un protocolo para la selección de los morfotipos con mayor actividad biotransformadora de CBR, el protocolo incluye el aislamiento en un medio selectivo con CBR en polvo, pruebas ...

  17. Asentamientos de rango menor (ARM en Tandil: transformaciones territoriales a partir de la renovación de los vínculos urbano-rurales

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    Guillermina Jacinto

    2011-11-01

    Full Text Available El trabajo presenta las transformaciones territoriales en asentamientos de rango menor (ARM del Partido de Tandil, identificadas e interpretadas a partir de la renovación de los vínculos urbano-rurales. El desarrollo de nuevos procesos muestra la necesidad de superar la visión unívoca de los ARM como centros de aprovisionamiento de servicio a los espacios rurales. Sin perder este rol, el desarrollo de otras funciones articuladas a las demandas de espacios y actores urbanos, muestran la complejidad de situaciones que se perfilan en la construcción de nuevas territorialidades e interpelan sobre los desafíos abiertos para una gestión local sustentable.

  18. OBSERVACIÓN DE RANGOS DE VUELO DE Bombus Atratus (Hymenoptera: Apidae EN AMBIENTES URBANOS Observation of Flight Ranges of Bombus Atratus (Hymenoptera: Apidae in Urban Environments

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    LAÍN PARDO

    2006-06-01

    Full Text Available Se estudió la capacidad de regreso de Bombus atratus a su colonia midiendo la cantidad de individuos que volvieron a ésta después de ser liberadas a diferentes distancias y en cuatro direcciones (norte, sur, este, oeste. Para ello se trasladó una colonia de B. atratus, proveniente de Tenjo Cundinamarca, al Departamento de Biología, Universidad Nacional de Colombia Sede Bogotá, se marcaron y liberaron un total de 100 forrajeras de las cuales regresaron 40. Hubo una relación lineal negativa clara entre la proporción de regresos al nido y las distancias del sitio de liberación, con reducción del número de abejorros capaces de regresar a medida que aumentaba la distancia al nido. El rango máximo observado al cual las abejas pudieron regresan al nido está entre 1.300m y 1.500m y un análisis de regresión lineal predice un rango de vuelo de 1,6 km.The return capacity of Bombus atratus to its colony was studied by measuring the quantity of individuals that returned to it, after being released at different distances and in four directions (north, south, east, west. We located a colony of B. atratus coming from Tenjo, Cundinamarca, at the Department of Biology, Universidad Nacional de Colombia, Bogotá. We marked and released a total of 100 workers of which 40 returned. There was a clear negative relationship between the proportion of bees returning to its nest and the distance from the released site, decreasing the number of bumblebees able to return as it increased the distance to the nest. The observed maximum range to which the bees found their nest was between 1,300 m and 1,500 m and a lineal regression analysis predicts a flight range of 1.6 km.

  19. SR-71 - Taxi on Ramp with Engines

    Science.gov (United States)

    1995-01-01

    This photo shows a head-on shot of NASA's SR-71A aircraft taxiing on the ramp at NASA's Dryden Flight Research Center, Edwards, California, heat waves from its engines blurring the hangars in the background. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the airstream. One of Dryden's SR-71s was used for the Linear Aerospike Rocket Engine, or LASRE Experiment. Another earlier project consisted of a series of flights using the SR-71 as a science camera platform for NASA's Jet Propulsion Laboratory in Pasadena

  20. REVISED FINAL REPORT – INDEPENDENT VERIFICATION SURVEY ACTIVITIES AT THE SEPARATIONS PROCESS RESEARCH UNIT SITES, NISKAYUNA, NEW YORK – DCN 0496-SR-06-1

    Energy Technology Data Exchange (ETDEWEB)

    Evan Harpenau

    2011-10-10

    The Separations Process Research Unit (SPRU) complex located on the Knolls Atomic Power Laboratory (KAPL) site in Niskayuna, New York, was constructed in the late 1940s to research the chemical separation of plutonium and uranium (Figure A-1). SPRU operated as a laboratory scale research facility between February 1950 and October 1953. The research activities ceased following the successful development of the reduction oxidation and plutonium/uranium extraction processes. The oxidation and extraction processes were subsequently developed for large scale use by the Hanford and Savannah River sites (aRc 2008a). Decommissioning of the SPRU facilities began in October 1953 and continued through the 1990s.

  1. SR-71 - In-flight from Tanker

    Science.gov (United States)

    1994-01-01

    Dryden's SR-71B, NASA 831, slices across the snow-covered southern Sierra Nevada Mountains of California after being refueled by an Air Force tanker during a 1994 flight. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the airstream. One of Dryden's SR-71s was used for the Linear Aerospike Rocket Engine, or LASRE Experiment. Another earlier project consisted of a series of flights using the SR-71 as a science camera platform for NASA's Jet Propulsion Laboratory in Pasadena, California. An upward

  2. Influences of Sr dose on the crystal structure parameters and Sr distributions of Sr-incorporated hydroxyapatite.

    Science.gov (United States)

    Guo, D G; Hao, Y Z; Li, H Y; Fang, C Q; Sun, L J; Zhu, H; Wang, J; Huang, X F; Ni, P F; Xu, K W

    2013-10-01

    Stoichiometric strontium-incorporated hydroxyapatite (Sr-HA) with different Sr concentrations [Sr/(Sr+Ca)] were synthesized using a wet chemical approach and characterized by X-ray diffraction, Fourier-transformed infrared absorption, X-ray photoelectron spectroscopy, and Rietveld Structure Refinement. The crystal lattice parameter, Sr distribution, chemical state of Sr, and also the relationships between their variations and the Sr concentrations have been intensively studied. The results show that both the crystal lattice parameters and crystal plane space of Sr-HA remarkably increase with the Sr concentration increasing. Whether Sr preferably occupies the Ca(I) site or Ca(II) site after incorporated into apatite lattice depends on the Sr number incorporated into apatite. All the Sr ions completely occupy the Ca(II) sites when the Sr concentration is below 5%. With the exception of partial Sr ions occupying the Ca(II) sites, the other Sr ions start to occupy the Ca(I) sites when the Sr concentration doped in HA is beyond 10%. The ratio of Sr ions occupying the Ca(I) sites increases with the further raising Sr concentration up to 20%. The Sr ions inherit the chemical state and environment of the original Ca(I) or Ca(II) site after incorporated into apatite. Copyright © 2013 Wiley Periodicals, Inc.

  3. OBTENCIÓN DE BACTERIAS BIOTRANSFORMADORAS DE CARBÓN DE BAJO RANGO A PARTIR DE MICROHÁBITATS CON PRESENCIA DE RESIDUOS CARBONOSOS

    Directory of Open Access Journals (Sweden)

    NELSON VALERO VALERO

    2012-01-01

    Full Text Available Se aislaron bacterias con actividad biotransformadora de carbón de bajo rango (CBR a partir de muestras ambientales con presencia de residuos de carbón en la mina “El Cerrejón”. Se aislaron 75 morfotipos bacterianos de los cuales 32 presentaron cre- cimiento en medio sólido mínimo de sales con carbón a 5 %. Se diseño un protocolo para la selección de los morfotipos con mayor actividad biotransformadora de CBR, el protocolo incluye el aislamiento en un medio selectivo con CBR en polvo, pruebas cualitativas y cuantitativas de solubilización de CBR en medios sólidos y líquido. El mecanismo de solubilización en las cepas que producen mayores valores de sustancias húmicas (SH estuvo asociado a cambios de pH en el medio, probablemente por la producción de sustancias alcalinas extracelulares. El mayor número de aislamientos y los aislamientos con mayor actividad solubilizadora sobre el CBR provienen de lodo con alto contenido de residuos de carbón y las rizósferas de Typha domingensis y Cenchrus ciliaris que crecen sobre sedimentos mezclados con partículas de carbón, este resultado sugiere que la obtención y capacidad de solubilización de CBR por parte de bacterias puede estar relacionada con el microhábitat donde se desarrollan las poblaciones.

  4. Influencia del microhábitat sobre la obtención y actividad de bacterias biotransformadoras de carbón de bajo rango

    Directory of Open Access Journals (Sweden)

    Rodríguez Luz Nidia

    2012-08-01

    Full Text Available Se aislaron bacterias con actividad biotransformadora de carbón de bajo rango (CBR a partir de muestras ambientales con presencia de residuos de carbón en la mina “El Cerrejón”. Se aislaron 75 morfotipos bacterianos de los cuales 32 presentaron crecimiento en medio sólido mínimo de sales con carbón al 5%. Se diseño un protocolo para la selección de los morfotipos con mayor actividad biotransformadora de CBR, el protocolo incluye el aislamiento en un medio selectivo con CBR en polvo, pruebas cualitativas y cuantitativas de solubilización de CBR en medios sólidos y líquido. El mecanismo de solubilización en las cepas que producen mayores valores de sustancias húmicas (SH está asociada a cambios de pH en el medio, debido probablemente a la producción de sustancias alcalinas extracelulares por las bacterias. El mayor número de cepas y las bacterias con mayor actividad solubilizadora sobre el CBR fueron aisladas de lodo con alto contenido de residuos de carbón y las rizósferas de Typha domingensis y Cenchrus ciliaris que crecen sobre sedimentos mezclados con partículas de carbón, este resultado sugiere que la obtención y capacidad de solubilización de CBR por parte de bacterias puede estar relacionada con el microhábitat donde se desarrollan las poblaciones.

  5. Los Plagiolophinae (Remy, 1976 nuevo rango (Perissodactyla, Mammalia del Eoceno de la Cuenca del Duero (Castilla y Leon, España

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    Cuesta Ruiz-Colmenares, M. A.

    1994-08-01

    Full Text Available The systematic study of the Plagiolophinae (Remy, 1976 nov. rank (Perissodactyla, Mammalia from the Eocene of the Duero Basin (Castilla y León, Spain has permitted the identification of two new species: Plagiolophus casasecaensis nov. sp. of the Casaseca site (middle Eocene, MP 13-14, Zamora province that is a very primitive species; and Plagiolophus mazateronensis nov. sp. of the Mazaterón (middle-upper Eocene, MP 16-17, Almazán subbasin, Soria province and Caenes sites (middle Eocene, MP 16, Salamanca province which are described by a special combination of primitive and derivative characteristics unknown in other species of the genus. Other forms poorly documented and attributable to genus Plagiolophus occur in Jambrina and El Viso-Sanzoles (MP 13-14, Zamora province, San Morales (MP 16, Salamanca province, Deza (upper Eocene, Soria province, Molino del Pico (upper Eocene-Oligocene, Zamora province, and Mazaterón. The genus Leptolophus that has been determined in Mazaterón, had only been known before in sorne French localities. This Plagiolophinae assemblage is clearly biogeographically different from the already known findings in occidental Europe and subpirenaic area.El estudio de los Plagiolophinae (Remy, 1976 nuevo rango (Perissodactyla, Mammalia del Eoceno de la Cuenca del Duero (Castilla y León, España ha permitido identificar dos nuevas especies: Plagiolophus casasecaensis nov. sp. del yacimiento de Casaseca (Eoceno medio, parte media, MP 13-14, provincia de Zamora caracterizada por un marcado primitivismo, y Plagiolophus mazateronensis nov. sp., del yacimiento de Mazaterón (Eoceno medio-superior, MP 16-17, subcuenca de Almazán, provincia de Soria y de Caenes (Eoceno medio, parte superior, MP 16, provincia de Salamanca, caracterizada por una peculiar combinación de caracteres primitivos y evolucionados, desconocida en el resto de especies del género. Otras formas escasamente documentadas atribuibles al género Plagiolophus

  6. Estudio cinético de la descomposición térmica del carbonato de Estroncio en el sistema SrCO3-Al2O3-SrSO4

    Directory of Open Access Journals (Sweden)

    Torres T, J.

    2008-10-01

    Full Text Available The thermal decomposition of strontium carbonate in the SrCO3-Al2O3-SrSO4 system was studied by thermal analysis under isothermal experiments. Powder of reactive grade of SrCO3, Al2O3 y SrSO4 in molar ratio 3:3:1 were prepared. The powders were heat treated from 750 to 1000 °C for 4 h. Loss weight for each temperature was registered and the kinetics parameter were determine using the classical fit method. The effect of mechanical activation of SrCO3 was studied as well. The reaction mechanism for 750 to 900 °C temperature range corresponded to a geometric shrinkage in the grain boundary (R1.1 with an activation energy of 106. 21 Kjmol-1. The reaction mechanism for 900 to 1100 °C temperature range corresponded to a nucleation and growing (P1.1 with an activation energy of 44.87 Kjmol-1. The activation energy was reduced in 35% for the samples that contained SrCO3 mechanically activated.La cinética de descomposición térmica del carbonato de Estroncio (SrCO3 en el sistema SrCO3-Al2O3-SrSO4 se estudió por medio de análisis térmico gravimétrico (ATG, utilizando el método isotérmico. Se prepararon mezclas de polvos 3:3:1 molar de SrCO3, Al2O3 y SrSO4 grado reactivo, las cuales fueron homogenizadas y tratadas a temperaturas entre 750 hasta 1100°C, por periodo de 4 horas. Adicionalmente se estudio el efecto del tiempo de activación mecánica del SrCO3 sobre la cinética de descomposición. Se obtuvieron curvas representativas de la pérdida de peso de las muestras al incrementar la temperatura, a partir de ellas se realizó el estudio cinético. Para el rango de temperatura de 750 a 900°C, el mecanismo de reacción que rige el proceso de descomposición corresponde a una contracción geométrica mediante la frontera de grano (R1.1 con una energía de activación (Ea de 106.21KJmol-1. En el rango de temperatura de 950 a 1100°C, el mecanismo de reacción que rige la descomposición corresponde a un proceso de nucleación y crecimiento (P1

  7. Pacific Northwest Laboratory quarterly report to ERDA Nuclear Research and Applications Division for April--June 1976. [WESF-produced /sup 90/SrF/sub 2/ and /sup 137/CsCl

    Energy Technology Data Exchange (ETDEWEB)

    Fullam, H.T.; Harmon, K.M.

    1976-07-01

    The long-term compatibility tests are continuing as scheduled. The first set of test couples (1000-hr exposure) were removed from the furnaces and sectioned. Analysis of the test specimens is now underway. Metallographic examination of the nonradioactive specimens has been completed, and evaluation of the micrographs indicates that fluoride attack of the TZM, Haynes Alloy 25, and Hastelloy C-276 specimens is similar to that observed in the earlier short-term tests. Thermal aging of Hastelloy C-4 Charpy specimens is continuing. The 5000-hr tests have been completed and the impact strength of the aged specimens determined. The results show a decrease in impact strength of specimens aged at 600 and 800/sup 0/C, confirming the results of the 1000-hr tests. The dissolution behavior of WESF-produced /sup 90/SrF/sub 2/ in demineralized water and natural seawater was measured. The dissolution rate of the WESF /sup 90/SrF/sub 2/ in seawater was 300 +- 30 ..mu..g Sr/hr-g Sr present, while the dissolution rate in demineralized water was 440 ..mu..g Sr/hr-g Sr present. Work continued on the preparation of topical reports covering various phases of the program. A program was started to assist Sandia Laboratories in the evaluation of competing technologies for sewage treatment.

  8. A = Ba, Sr or Pb

    Indian Academy of Sciences (India)

    Unknown

    tion in the transmission mode. The samples were rotated ... The profiles were fitted using a pseudo-Voigt function. The Chebyshev ... Crystal data for ABi4Ti4O15 (A = Ba, Sr or Pb) at. 298 K. Formula. BaBi4Ti4O15. SrBi4Ti4O15. PbBi4Ti4O15. Formula weight. 1404⋅85. 1355⋅13. 1474⋅70. Colour. Yellow. Yellow. Yellow.

  9. 88Sr/86Sr fractionation and calcite accumulation rate in the Sea of Galilee

    Science.gov (United States)

    Fruchter, N.; Lazar, B.; Nishri, A.; Almogi-Labin, A.; Eisenhauer, A.; Be'eri Shlevin, Y.; Stein, M.

    2017-10-01

    This study used the Sea of Galilee (Lake Kinneret, northern Israel) as a ;natural laboratory; to investigate the fractionation of the stable Sr isotope ratio (88Sr/86Sr) during precipitation of inorganic (primary) calcite from the lake's water. It was found that the absolute value of the 88Sr/86Sr fractionation factor, Δ88/86Sr, increases as a function of calcite accumulation rate (Δ88/86Sr [‰] = -0.05 to 0.042·log(R) [μmol·m-2·d-1], where R is the accumulation rate). Furthermore, the 87Sr/86Sr and 88Sr/86Sr ratios in the freshwater and brines that enter the lake were used to calculate the contributions of these sources to the lake Sr budget. The 87Sr/86Sr and 88Sr/86Sr ratios were measured in primary calcite, aragonite shells of live Melanopsis, lake water and various water sources to the lake. While the lake's 87Sr/86Sr ratios are determined by the mixture of freshwater of the Jordan River and saline springs, the 88Sr/86Sr ratios of the lake reflect a more complex mass balance that includes the effect of isotopic fractionation associated with the precipitation of primary calcite. Data analysis suggests that long-term accumulation of inorganic calcite depleted in the heavy isotope 88Sr, results in an increase of the δ88/86Sr value of the lake water by 0.05‰. In contrast to the primary inorganic calcite, biogenic aragonite of the Melanopsis shells show a rather constant 88Sr/86Sr water-CaCO3 fractionation of Δ88/86Sr = -0.21‰. Similar Δ88/86Sr values were reported for the precipitation of coralline and inorganic aragonite from seawater and the precipitation of inorganic calcite from various continental waters. The Δ88/86Sr value of inorganic calcite is modulated by the rate of carbonate precipitation, as noted above and shown by precipitation experiments. Massive precipitation of primary calcite with a wide spread of accumulation rates occurs during the spring phytoplankton bloom in Lake Kinneret. The bloom dictates the degree of calcite saturation

  10. Thermal infrared and microwave absorbing properties of SrTiO{sub 3}/SrFe{sub 12}O{sub 19}/polyaniline nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Hosseini, Seyed Hossein, E-mail: shhosseini@iiau.ac.ir [Department of Chemistry, Faculty of Science, Islamshahr Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Zamani, Parisa [Department of Applied Chemistry, Faculty of Pharmaceutical Chemistry, Pharmaceutical Sciences Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Mousavi, S.Y. [Faculty of Passive Defense, Imam Hossein University, Tehran (Iran, Islamic Republic of)

    2015-09-25

    Graphical abstract: We have developed a new perspective of applications and properties of conducting polymers. The combination of absorption ability prepared nanocomposites in the present of PANI display a great potential in organization of shielding structures into thermal IR and microwave. Further investigations using other conducting polymers to demonstrate their capability for advance thermal IR and microwave shielding devices is under way. The application of these samples may improve the IR thermographic detection, catalysis, sensors, magnetic data storage, electromagnetic resonance wave absorption, photonic crystals, and microelectronic devices and military aspects. - Highlights: • The SrTiO{sub 3}/SrFe{sub 12}O{sub 19}/PANI exhibited electric and electromagnetic properties. • The SrTiO{sub 3}/SrFe{sub 12}O{sub 19}/PANI has shielding structures into thermal IR and microwave. • Increasing weight ratios and thicknesses will increase thermal IR ability. • Increasing weight ratios and thicknesses will increase microwave absorption ability. - Abstract: Polyaniline (PANI) as a unique polymer that also has electromagnetic absorption used as the substrate. In this research, SrTiO{sub 3} was synthesized as IR absorbent and core and then SrFe{sub 12}O{sub 19} as microwave absorbent was prepared on SrTiO{sub 3} via co-precipitation method as the first shell. As the next step, PANI was coated on SrTiO{sub 3}/SrFe{sub 12}O{sub 19} nanoparticles via in situ polymerization by multi core–shell structures (SrTiO{sub 3}/SrFe{sub 12}O{sub 19}/PANI). Nanometer size and structures of samples were measured by TEM, XRD and FTIR. Morphology of nanocomposite was showed by SEM images. The magnetic and electric properties were also performed by VSM and four probe techniques. Thermal infrared (IR) absorption and microwave reflection loss of nanocomposites were investigated at 10–40 μm and 8–12 GHz, IR and microwave frequencies, respectively. The results showed that the Sr

  11. Antlers of Cervus elaphus as biomonitors of {sup 90}Sr in the environment

    Energy Technology Data Exchange (ETDEWEB)

    Baeza, A.; Vallejo, I. [LARUEX, Dpt. Applied Physics, Faculty of Veterinary Sciences, University of Extremadura, Avda, 10003 Caceres (Spain); Guillen, J., E-mail: fguillen@unex.e [LARUEX, Dpt. Applied Physics, Faculty of Veterinary Sciences, University of Extremadura, Avda, 10003 Caceres (Spain); Salas, A.; Corbacho, J.A. [LARUEX, Dpt. Applied Physics, Faculty of Veterinary Sciences, University of Extremadura, Avda, 10003 Caceres (Spain)

    2011-03-15

    Adequate radioprotection of the environment requires the identification of biomonitors sensitive to the variation of its radionuclide content. Due to the chemical similarities between calcium and strontium, calcified tissues of mammals are considered to be good {sup 90}Sr biomonitors. This work considered Cervus elaphus antlers which, being shed annually, can give information about the importance of radiostrontium contamination in an ecosystem in the time period required for the growth of the antler. The samples were collected at various points of W and SW Spain. The mean value of their {sup 90}Sr content was (70 {+-} 43 (S.D.)) Bq/kg d.w., range (16-218) Bq/kg d.w., and the radionuclide was evenly distributed in the different parts of the antler. There was a good correlation between the antlers' {sup 90}Sr content and the {sup 90}Sr deposited in the soil. The antlers' content of {sup 226}Ra (from the natural uranium series) and the contents of some stable elements (Ca, Mg, Sr, and K) were also determined. The values for these stable elements were practically constant in the analyzed samples, and the concentrations measured decreased in the following order: Ca > Mg > K > Sr > {sup 90}Sr > {sup 226}Ra - Research highlights: {yields} There was a good correlation between the antlers' {sup 90}Sr content and the {sup 90}Sr deposited in the soil. {yields} The content of stable elements (Ca, Mg, Sr, K) in the analyzed antlers were practically constant. {yields} The concentrations measured decreased in the following order: Ca > Mg > K > Sr >{sup 90}Sr >{sup 226}Ra.

  12. Transgenerational isotopic marking of carp Cyprinus carpio, L. using a 86Sr /84Sr double spike

    Science.gov (United States)

    Zitek, Andreas; Cervicek, Magdalena; Irrgeher, Johanna; Horsky, Monika; Kletzl, Manfred; Weismann, Thomas; Prohaska, Thomas

    2013-04-01

    Transgenerational isotopic marking has been recognized recently as an effective tool for mass marking and tracking of individual fish to their original source. Compared to other conventional marking techniques, transgenerational marking offers several advantages. Most importantly, it is possible to mark all offspring of one individual female without the necessity of handling eggs or larval fish. Furthermore it is possible to vary the concentrations of individual isotopes to obtain specific marks for individual female fish. An enriched isotopic spike solution is usually applied to gravid female spawners by injection into the body cavity for transgenerational marking. The isotope is then incorporated into the central otolith region of the offspring which is known to be built up by maternally derived material. Within this study transgenerational marking of a typical cyprinid fish species, Cyprinus carpio, L., was tested using a 86Sr /84Sr double spike. Buffered solutions with different isotopic composition and concentrations were administered to 4 female individuals by intraperitoneal injection 5 days before spawning, while one female was injected a blank solution. After spawning, otoliths (Lapilli) from juvenile fish were sampled at the age of about 5 months at fish sizes between 3 and 4 cm and analyzed for their isotopic composition by LA-ICPMS applying cross sectional line scans. Central otolith regions of the progeny showed a shift in the natural isotope ratios for the administered isotopes. Deconvolution of the blank corrected measurement data of the Sr isotopes was done to trace back the original spike ratio. The different spike ratios could be well distinguished reflecting the original composition of the spike solution. This study proved that it is possible to create batch-specific unique transgenerational marks in otolith cores by varying the concentrations of two naturally occurring Sr isotopes. This method has high potential to reduce the marking effort for

  13. The 87Sr/86Sr aquatic isoscape of the Danube catchment from the source to the mouth as tool for studying fish migrations

    Science.gov (United States)

    Zitek, Andreas; Tchaikovsky, Anastassiya; Irrgeher, Johanna; Waidbacher, Herwig; Prohaska, Thomas

    2014-05-01

    Isoscapes - spatially distributed isotope patterns across landscapes - are increasingly used as important basis for ecological studies. The natural variation of the isotopic abundances in a studied area bears the potential to be used as natural tracer for studying e.g. migrations of animals or prey-predator relations. The 87Sr/86Sr ratio is one important tracer, since it is known to provide a direct relation of biological samples to geologically distinct regions, as Sr isotopes are incorporated into living tissues as a proxy for calcium and taken up from the environment without any significant fractionation. Although until now the focus has been mainly set on terrestrial systems, maps for aquatic systems are increasingly being established. Here we present the first 87Sr/86Sr aquatic isoscape of the Danube catchment, the second largest river catchment in Europe, from near its source starting at river km 2581 in Germany down to its mouth to river km 107 in Romania. The total length of the river Danube is 2780 km draining a catchment area 801 463 km2 (10 % of the European continent). The major purpose of this study was to assess the potential of the 87Sr/86Sr isotope ratio to be used as tool for studying fish migrations at different scales in the entire Danube catchment. Within the Joint Danube Research 3 (JDS 3), the biggest scientific multi-disciplinary river expedition of the World in 2013 aiming at the assessment of the ecological status and degree of human alterations along the river Danube, water samples were taken at 68 pre-defined sites along the course of the river Danube including the major tributaries as a basis to create the so called 'Isoscape of the Danube catchment'. The determination of 87Sr/86Sr isotope ratio in river water was performed by multicollector-sector field-inductively coupled plasma-mass spectrometry (MC-SF-ICP-MS). The JDS 3 data were combined with existing data from prior studies conducted within the Austrian part of the Danube catchment

  14. Rapid method for determining Sr-89 and Sr-90 using Cherenkov and proportional counting; Schnellmethode zur Bestimmung von SR-89 und SR-90 durch Cerenkov- und Proportionalzaehlermessungen

    Energy Technology Data Exchange (ETDEWEB)

    Lange, S.; Wende, C.; Schwokowski, R.; Alisch-Mark, M.; Abraham, A.; Heinrich, T. [Staatliche Betriebsgesellschaft fuer Umwelt und Landwirtschaft, Radebeul (Germany)

    2016-07-01

    A rapid method for determining Sr-89 and Sr-90 in water, milk and biological samples has been developed and tested. After sample preparation strontium is separated by extraction chromatography using Sr resin. Eluate is divided and transfered to LSC vial and filter paper by SrCO{sub 3} precipitation. A Hidex 300 SL TDCR liquid scintillation counter and Thermo Fisher low level proportional counter have been used. Chemical yield of Sr-85 tracer is determined by Gamma spectroscopy. Uncertainty budget, decision threshold and detection limit are calculated in accordance with GUM and ISO 11929.

  15. Strontium (Sr) elicits odontogenic differentiation of human dental pulp stem cells (hDPSCs): A therapeutic role for Sr in dentine repair?

    Science.gov (United States)

    Huang, Mei; Hill, Robert G; Rawlinson, Simon C F

    2016-07-01

    used widely in dental practise, its potential effects on odontoblasts have been ignored. Our study provides the first evidence that Sr (exogenous and that derived from a bioglass (BG)) can stimulate dentinogenesis in human dental pulp stem cells (hDPSCs) by promoting their proliferation, differentiation and mineralisation in vitro. Therefore, while previously unrecognised, Sr BG is likely to be beneficial in atraumatic dentistry practise and maintenance of a competent tooth in conditions such as caries. Repair of defected dentine is still one of the main challenges in dental research and annually untreated caries results in the loss of productivity equivalent to US$ 27 billion. Advances in tissue engineering technology, alongside the use of dental pulp stem cells provide an approach to achieve dentine regeneration. Understanding the actions of Sr will permit a more controlled application of Sr in the clinic. These data are thus likely to be of great interest to the material scientists, biological researchers, clinicians and manufacturers of dental products. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  16. lenohumeral rotation range deficit in professional rugby players: A cross sectional study. (Déficit en el rango de rotación glenohumeral en jugadoresde rugby profesional: Un estudio de corte transversal.

    Directory of Open Access Journals (Sweden)

    Matías Osorio Feito

    2011-01-01

    Full Text Available AbstractThe aim was to evaluate the internal rotation, external rotation and total range of motion of shoulder in professional rugby players and associated factors. 104 rugby players and 30 healthy volunteers were interrogated and clinically examined. 19.23% of the rugby players were excluded by history of shoulder luxation or surgery. 84 rugby players with 24.28±5.37 years old were finally included in the study. The groups were analyzed with Mann-Whitney test, Fisher’s exact test, Linear Regression and a Logistic Regression. It was found that professional rugby players had less internal, external and total range of glenohumeral rotation compared with control group. In the Logistic Regression, the age is a risk factor for external rotation range deficit (Odds Ratio= 1.58. Instead, the years of experience are a protector factor (Odds Ratio= 0.63. We can conclude that glenohumeral rotation range is diminished in professional rugby players and is associated with age and years of experience.ResumenEl objetivo de este estudio fue evaluar la rotación interna, rotación externa, el rango total de movimiento del hombro y factores asociados en jugadores de rugby profesional . 104 jugadores de rugby y 30 voluntarios sanos fueron interrogados y examinados clínicamente. Un 19.23% de los jugadores de rugby fueron excluidos por historial de luxación o cirugía de hombro. 84 jugadores de rugby, con 24.28 ± 5.37 años de edad fueron finalmente incluidos en el estudio. Los grupos se analizaron con la prueba de Mann-Whitney, la prueba exacta de Fisher, regresión lineal y regresión logística. Se encontró que los jugadores profesionales de rugby tienen menos rango de rotación interna, externa y total en comparación con el grupo control. En la regresión logística, la edad es un factor de riesgo de déficit de rotación externa (OR = 1.58. En cambio, los años de experiencia son un factor protector (OR = 0.63. Podemos concluir que el rango de rotaci

  17. Sr Isotopes at the Onset of the Ice Ages at the Northern Apennines

    Science.gov (United States)

    Fuchs, Rita; Lazar, Boaz; Angiolini, Lucia; Crippa, Gaia; Stein, Mordechai

    2017-04-01

    Sr isotopes can be used to constrain the marine Sr budget. The temporal variations in the 87Sr/86Sr ratios (radiogenic Sr) have been reconstructed over the past few decades based on marine macro and micro fossils data (e.g. brachiopods and foraminifera). It is used to constrain the sources and amounts of strontium that dictate the temporal variations in oceanic Sr throughout the Phanerozoic. On the other hand, the study of processes controlling the composition stable Sr isotopes (δ88/86Sr) is very new and only limited research was conducted on this topic during the past few years. Up to date, no δ88/86Sr data are available for considerable parts of Earth's history and the contribution of the potential Sr sources to the oceans is poorly constrained. Here, we set to examine the behavior of radiogenic and stable Sr isotopes in the marine environment of the northern Apennines (Italy) during the time interval of the late Pliocene to early-Middle Pleistocene - upon the onset of ice ages in the northern latitudes. We collected fossil mollusks from outcrops of the Arda and Stirone Rivers that are rich in bivalves, brachiopods, foraminifera (that were used for establishing the chronostratigraphy of the sections) and other genera. Ecological and sedimentological analysis of the section suggest a normal marine environment of depth range of several tens of meters that existed on the southern flanks of the large Po embayment. In order to evaluate the potential of the fossil assemblages in the Arda and Stirone sections to serve as reliable recorders of the marine δ88/86Sr of seawater during the desired period, we examined mineralogical and chemical properties of the fossils (e.g. distribution of trace elements like Sr and Mg in the skeletons, microstructures like secondary fillings of punctate shells in brachiopod) and measured the 87Sr/86Sr ratios. Among the species analyzed, Aequipecten opercularis (bivalve) and Glycymeris inflata (bivalve) have aragonite skeletons that

  18. Effect of active stretching on hip flexion range of motion: 15 versus 30 seconds Efecto del estiramiento activo sobre el rango de movimiento de la flexión de cadera: 15 versus 30 segundos

    Directory of Open Access Journals (Sweden)

    P. Sainz de Baranda

    2010-09-01

    Full Text Available

    The main purpose of the present study was to examine the efficacy of 12-weeks active stretching program to improve hip flexion range of motion in young adults, as son as evaluate the efficacy of two different stretching durations: 15 and 30 second. A total of 82 subjects young adults volunteer (57 men and 25 women were the participants in this study. The participants were distributed by means of counterbalance in two stretching groups: a first group of 15 seconds of stretching duration (n=35, a second group with 30 seconds of stretching duration (n=47. Straight leg raise test (SLR. Was used to assess the hip flexion range of motion. Results showed that the active stretching technique was effective to increased hamstring flexibility independently of the stretching duration (p<0,05. Not significant differences were found between the different stretching groups (p>0,05. Conclusion: The active stretching technique is effective to improve hip flexion range of motion, being equal of effective 15 and 30 seconds of stretching duration.
    Key Words:Hamstring, Flexibility, Range of motion, Active Stretching, Stretching duration.

    El objetivo principal de este estudio fue valorar la eficacia de un programa de estiramientos activos con una duración de 12 semanas para aumentar el rango de movimiento de la flexión de cadera en adultos jóvenes, así como comparar la eficacia de dos duraciones diferentes del estiramiento, 15 y 30 segundos. La muestra estuvo compuesta por un total de 82 sujetos adultos jóvenes sanos voluntarios (57 Hombres y 25 Mujeres. La muestra fue distribuida mediante contrabalanceo en dos grupos de trabajo; un primer grupo de 15 segundos de duración del estiramiento (n=35, un segundo grupo con 30 segundos de duración del mismo (n=47. Para valorar el rango de movimiento de la flexión de cadera se utilizó el test angular

  19. Efecto del estiramiento estático de 15, 30 y 60 segundos sobre el rango de movimiento de la flexión de cadera con rodilla extendida

    OpenAIRE

    Claudia Lucía Ariza-García; Milena del Carmen Boneth-Collante; Adriana Angarita-Fonseca; Angelica María Corredor-Moreno; Silvia Milena Cárdenas-Castellanos

    2014-01-01

    Objetivo: Evaluar el efecto de tres duraciones de estiramiento estático pasivo, 15, 30 y 60 segundos (s) para aumentar el rango de movimiento de la flexión de cadera (ROM-FC). Metodología: Ensayo Clínico Controlado Aleatorizado. Nueve estudiantes mujeres (21,7 ± 4,3 años) fueron asignadas aleatoriamente a tres grupos, 15 (G15), 30 (G30) y 60 (G60) s; n = 3 en cada grupo. El estiramiento de la musculatura isquitotibial se realizó en decúbito supino, máxima flexión de cadera, rodilla extendida ...

  20. 88Sr/86Sr fractionation and calcite accumulation rate in the Sea of Galilee

    Science.gov (United States)

    Fruchter, Noa; Lazar, Boaz; Nishri, Aminadav; Almogi-Labin, Ahuva; Eisenhauer, Anton; Beeri-Shlevin, Yaron; Stein, Mordechai

    2017-04-01

    This study uses Lake Kinneret (Sea of Galilee, northern Israel) as a natural laboratory to investigate the fractionation of the stable Sr isotope ratio (88Sr/86Sr) during precipitation of authigenic calcite in the water column, and evaluates the dependence of the fractionation 87Sr/86Sr and 88Sr/86Sr ratios in the freshwater and brines that enter the lake are used to calculate the relative contributions of these sources to the Sr budget of the modern lake. The 87Sr/86Sr and 88Sr/86Sr ratios were measured in authigenic calcite, living Melanopsis shells, lake water and various water sources to the lake. While the lake's 87Sr/86Sr ratios are determined by the mixture of freshwater supplied mainly by the Jordan River and saline springs, the 88Sr/86Sr ratios of the lake reflect a more complex mass balance that includes the effect of isotopic fractionation during the precipitation of authigenic calcite. The data show a significant long-term effect of calcite accumulation on the stable Sr isotope ratio of the lake, increasing the 88Sr/86Sr of the water by 0.04 ‰. In contrast to the authigenic calcite, biogenic aragonite shells are shown to have a rather constant 88Sr/86Sr water-CaCO3 fractionation of precipitation of coralline and chemical aragonite from seawater and the precipitation of authigenic calcite from various continental waters. The field data of the present study suggests that the fractionation of 88Sr/86Sr in authigenic calcite represents a kinetic fractionation that varies with precipitation rate, in addition to the constant thermodynamic property. Massive precipitation of authigenic calcite occurs in Lake Kinneret during the spring phytoplankton bloom as the latter increases considerably the degree of calcite saturation. The correlation between accumulation rate can be therefore used as a tool to reconstruct paleo-environmental variations by analyzing the 88Sr/86Sr ratio in authigenic CaCO3 in core sections.

  1. SR-71 - In-flight Close-up from Tanker

    Science.gov (United States)

    1994-01-01

    This extreme close-up of the SR-71B operated by NASA's Dryden Flight Research Center, Edwards, California, gives an unusual view of the twin cockpit of Dryden's SR-71B, NASA 831, and its helmeted crew members. The photo was taken from an Air Force tanker refueling the Blackbird during a 1994 flight. The Mach 3 Blackbird aircraft were loaned to NASA by the U.S. Air Force for high-speed, high-altitude aeronautical research. Capable of flying more than 2200 mph and at altitudes of over 85,000 feet, they are excellent platforms for research and experiments in aerodynamics, propulsion, structures, thermal protection materials, atmospheric studies, and sonic boom characterization. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data

  2. Effect of Sr Content and Strain on Sr Surface Segregation of La 1–x Sr x Co 0.2 Fe 0.8 O 3-δ as Cathode Material for Solid Oxide Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Yang; Ludwig, Karl F.; Woicik, Joseph C.; Gopalan, Srikanth; Pal, Uday B.; Kaspar, Tiffany C.; Basu, Soumendra N.

    2016-10-12

    Strontium doped lanthanum cobalt ferrite (LSCF) is a widely used cathode material due to its high electronic and ionic conductivity, and reasonable oxygen surface exchange coefficient. However, LSCF can have long-term stability issues such as surface segregation of Sr during solid oxide fuel cell (SOFC) operation, which can adversely affect the electrochemical performance. Thus, understanding the nature of the Sr surface segregation phenomenon, and how it is affected by the composition of LSCF and strain are critical. In this research, heteroepitaxial thin films of La1-x SrxCo0.2Fe0.8O3- with varying Sr content (x = 0.4, 0.3, 0.2) were deposited by pulsed laser deposition (PLD) on single crystal NdGaO3, SrTiO3 and GdScO3 substrates, leading to different levels of strain in the films. The extent of Sr segregation at the film surface was quantified using synchrotron-based total reflection x-ray fluorescence (TXRF), and atomic force microscopy (AFM). The electronic structure of the Sr-rich phases formed on the surface was investigated by hard X-ray photoelectron spectroscopy (HAXPES). The extent of Sr segregation was found to be a function of the Sr content in bulk. Lowering the Sr content from 40% to 30% reduced the surface segregation, but further lowering the Sr content to 20% increased the segregation. The strain of LSCF thin films on various substrates was measured using high-resolution x-ray diffraction (HRXRD) and the Sr surface segregation was found to be reduced with compressive strain and enhanced with tensile strain present within the thin films. A model was developed correlating the Sr surface segregation with Sr content and strain effects to explain the experimental results.

  3. Tracing of aerosol sources in an urban environment using chemical, Sr isotope, and mineralogical characterization.

    Science.gov (United States)

    Duarte, Regina M B O; Matos, João T V; Paula, Andreia S; Lopes, Sónia P; Ribeiro, Sara; Santos, José Francisco; Patinha, Carla; da Silva, Eduardo Ferreira; Soares, Rosário; Duarte, Armando C

    2017-04-01

    In the framework of two national research projects (ORGANOSOL and CN-linkAIR), fine particulate matter (PM 2.5 ) was sampled for 17 months at an urban location in the Western European Coast. The PM 2.5 samples were analyzed for organic carbon (OC), water-soluble organic carbon (WSOC), elemental carbon (EC), major water-soluble inorganic ions, mineralogical, and for the first time in this region, strontium isotope ( 87 Sr/ 86 Sr) composition. Organic matter dominates the identifiable urban PM 2.5 mass, followed by secondary inorganic aerosols. The acquired data resulted also in a seasonal overview of the carbonaceous and inorganic aerosol composition, with an important contribution from primary biomass burning and secondary formation processes in colder and warmer periods, respectively. The fossil-related primary EC seems to be continually present throughout the sampling period. The 87 Sr/ 86 Sr ratios were measured on both the labile and residual PM 2.5 fractions as well as on the bulk PM 2.5 samples. Regardless of the air mass origin, the residual fractions are more radiogenic (representative of a natural crustal dust source) than the labile fractions, whose 87 Sr/ 86 Sr ratios are comparable to that of seawater. The 87 Sr/ 86 Sr ratios and the mineralogical composition data further suggest that sea salt and mineral dust are important primary natural sources of fine aerosols throughout the sampling period.

  4. Tracing thermal aquifers of El Chichón volcano-hydrothermal system (México) with 87Sr/ 86Sr, Ca/Sr and REE

    Science.gov (United States)

    Peiffer, L.; Taran, Y. A.; Lounejeva, E.; Solís-Pichardo, G.; Rouwet, D.; Bernard-Romero, R. A.

    2011-08-01

    The volcano-hydrothermal system of El Chichón volcano, Chiapas, Mexico, is characterized by numerous thermal manifestations including an acid lake, steam vents and boiling springs in the crater and acid and neutral hot springs and steaming ground on the flanks. Previous research on major element chemistry reveals that thermal waters of El Chichón can be divided in two groups: (1) neutral waters discharging in the crater and southern slopes of the volcano with chloride content ranging from 1500 to 2200 mg/l and (2) acid-to-neutral waters with Cl up to 12,000 mg/l discharging at the western slopes. Our work supports the concept that each group of waters is derived from a separate aquifer (Aq. 1 and Aq. 2). In this study we apply Sr isotopes, Ca/Sr ratios and REE abundances along with the major and trace element water chemistry in order to discriminate and characterize these two aquifers. Waters derived from Aq. 1 are characterized by 87Sr/ 86Sr ratios ranging from 0.70407 to 0.70419, while Sr concentrations range from 0.1 to 4 mg/l and Ca/Sr weight ratios from 90 to 180, close to average values for the erupted rocks. Waters derived from Aq. 2 have 87Sr/ 86Sr between 0.70531 and 0.70542, high Sr concentrations up to 80 mg/l, and Ca/Sr ratio of 17-28. Aquifer 1 is most probably shallow, composed of volcanic rocks and situated beneath the crater, within the volcano edifice. Aquifer 2 may be situated at greater depth in sedimentary rocks and by some way connected to the regional oil-gas field brines. The relative water output (l/s) from both aquifers can be estimated as Aq. 1/Aq. 2-30. Both aquifers are not distinguishable by their REE patterns. The total concentration of REE, however, strongly depends on the acidity. All neutral waters including high-salinity waters from Aq. 2 have very low total REE concentrations (< 0.6 μg/l) and are characterized by a depletion in LREE relative to El Chichón volcanic rock, while acid waters from the crater lake (Aq. 1) and acid

  5. SR-71 Mid-air Refueling with KC-135 Tanker

    Science.gov (United States)

    1995-01-01

    NASA Dryden Flight Research Center's SR-71B, tail number 831, is seen here receiving air refueling from a USAF tanker during a July, 1995 flight. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the airstream. One of Dryden's SR-71s was used for the Linear Aerospike Rocket Engine, or LASRE Experiment. Another earlier project consisted of a series of flights using the SR-71 as a science camera platform for NASA's Jet Propulsion Laboratory in Pasadena, California. An upward-looking ultraviolet video camera placed in

  6. SR-71B - in Flight - View from Air Force Tanker

    Science.gov (United States)

    1997-01-01

    This look-down view shows NASA 831, an SR-71B flown by Dryden Flight Research Center, Edwards, California, as it cruises over the Mojave Desert. The photo was from an Air Force refueling tanker taken on a 1997 mission. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the airstream. One of Dryden's SR-71s was used for the Linear Aerospike Rocket Engine, or LASRE Experiment. Another earlier project consisted of a series of flights using the SR-71 as a science camera platform for NASA's Jet Propulsion Laboratory in

  7. Luminescent studies of impurity doped SrS phosphors

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 28; Issue 1 ... SrS phosphors; ESR; photoluminescence; thermoluminescence. Abstract. SrS phosphors activated with Ce and Dy ions were prepared by solid-state diffusion method. Photoluminescent study was carried out on SrS : Ce, SrS : Dy and SrS : Dy, Ce.

  8. Effect of Wood Aging on Wine Mineral Composition and 87Sr/86Sr Isotopic Ratio.

    Science.gov (United States)

    Kaya, Ayse D; Bruno de Sousa, Raúl; Curvelo-Garcia, António S; Ricardo-da-Silva, Jorge M; Catarino, Sofia

    2017-06-14

    The evolution of mineral composition and wine strontium isotopic ratio 87Sr/86Sr (Sr IR) during wood aging were investigated. A red wine was aged in stainless steel tanks with French oak staves (Quercus sessiliflora Salisb.), with three industrial scale replicates. Sampling was carried out after 30, 60, and 90 days of aging, and the wines were evaluated in terms of general analysis, phenolic composition, total polysaccharides, multielement composition, and Sr IR. Li, Be, Mg, Al, Sc, Ti, V, Mn, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, Zr, Mo, Sb, Cs, Ba, Pr, Nd, Sm, Eu, Dy, Ho, Er, Yb, Lu, Tl, and Pb elements and 87Sr/86Sr were determined by quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS) and Na, K, Ca, and Fe by flame atomic absorption spectrometry (FAAS). Two-way ANOVA was applied to assess wood aging and time effect on Sr IR and mineral composition. Wood aging resulted in significantly higher concentrations of Mg, V, Co, Ni, and Sr. At the end of the aging period, wine exhibited statistically identical Sr IR compared to control. Study suggests that wood aging does not affect 87Sr/86Sr, not precluding the use of this parameter for wine traceability purposes.

  9. Strontium (Sr) and silver (Ag) loaded nanotubular structures with combined osteoinductive and antimicrobial activities.

    Science.gov (United States)

    Cheng, Hao; Xiong, Wei; Fang, Zhong; Guan, Hanfeng; Wu, Wei; Li, Yong; Zhang, Yong; Alvarez, Mario Moisés; Gao, Biao; Huo, Kaifu; Xu, Jiangwen; Xu, Na; Zhang, Chengcheng; Fu, Jijiang; Khademhosseini, Ali; Li, Feng

    2016-02-01

    Two frequent problems are associated with the titanium surfaces of bone/dental implants: lack of native tissue integration and associated infection. These problems have prompted a significant body of research regarding the modification of these surfaces. The present study describes a hydrothermal treatment for the fabrication of strontium (Sr) and silver (Ag) loaded nanotubular structures with different tube diameters on titanium surfaces. The Sr loading from a Sr(OH)2 solution was regulated by the size of the inner diameter of the titanium nanotubes (NT) (30nm or 80nm, formed at 10V or 40V, respectively). The quantity of Ag was adjusted by immersing the samples in 1.5 or 2.0M AgNO3 solutions. Sr and Ag were released in a controllable and prolonged matter from the NT-Ag.Sr samples, with negligible cytotoxicity. Prominent antibacterial activity was observed due to the release of Ag. Sr incorporation enhanced the initial cell adhesion, migration, and proliferation of preosteoblast MC3T3-E1 cells. Sr release also up-regulated the expression of osteogenic genes and induced mineralization, as suggested by the presence of more mineralized calcium nodules in cells cultured on NT-Ag.Sr surfaces. In vivo experiments showed that the Sr-loaded samples accelerated the formation of new bone in both osteoporosis and bone defect models, as confirmed by X-ray, Micro-CT evaluation, and histomorphometric analysis of rats implanted with NT-Ag.Sr samples. The antibacterial activity and outstanding osteogenic properties of NT-Ag.Sr samples highlight their excellent potential for use in clinical applications. Two frequent problems associated with Ti surfaces, widely used in orthopedic and dental arenas, are their lack of native tissue integration and risk of infection. We describe a novel approach for the fabrication of strontium (Sr) and silver (Ag) loaded nanotubular structures on titanium surfaces. A relevant aspect of this work is the demonstration of long-lasting and controllable

  10. Origin of interface magnetism in BiMnO3/SrTiO3 and LaAlO3/SrTiO3 heterostructures.

    Science.gov (United States)

    Salluzzo, M; Gariglio, S; Stornaiuolo, D; Sessi, V; Rusponi, S; Piamonteze, C; De Luca, G M; Minola, M; Marré, D; Gadaleta, A; Brune, H; Nolting, F; Brookes, N B; Ghiringhelli, G

    2013-08-23

    Possible ferromagnetism induced in otherwise nonmagnetic materials has been motivating intense research in complex oxide heterostructures. Here we show that a confined magnetism is realized at the interface between SrTiO3 and two insulating polar oxides, BiMnO3 and LaAlO3. By using polarization dependent x-ray absorption spectroscopy, we find that in both cases the magnetism can be stabilized by a negative exchange interaction between the electrons transferred to the interface and local magnetic moments. These local magnetic moments are associated with magnetic Ti3+ ions at the interface itself for LaAlO3/SrTiO3 and to Mn3+ ions in the overlayer for BiMnO3/SrTiO3. In LaAlO3/SrTiO3 the induced magnetism is quenched by annealing in oxygen, suggesting a decisive role of oxygen vacancies in this phenomenon.

  11. Research Update: Diode performance of the Pt/Al2O3/two-dimensional electron gas/SrTiO3 structure and its time-dependent resistance evolution

    Science.gov (United States)

    Moon, Taehwan; Jung, Hae Jun; Kim, Yu Jin; Park, Min Hyuk; Kim, Han Joon; Kim, Keum Do; Lee, Young Hwan; Hyun, Seung Dam; Park, Hyeon Woo; Lee, Sang Woon; Hwang, Cheol Seong

    2017-04-01

    Time domain electric pulse measurements were conducted on a capacitor consisting of a Pt film as the top electrode, atomic-layer-deposited 6.5-nm-thick amorphous Al2O3 as the dielectric layer, and two-dimensional electron gas (2DEG) at the interface between Al2O3 and SrTiO3 as the bottom electrode. The sample showed highly useful current-voltage characteristics as the selector in cross-bar array resistance switching random access memory. The long-term (order of second) variation in the leakage current when the Pt electrode was positively biased was attributed to the field-induced migration of oxygen vacancies between the interior of the Al2O3 and the 2DEG region. Relaxation of the vacancy concentration occurred even at room temperature.

  12. RANGOS DE CONTROL DE HUMEDAD RELATIVA Y TEMPERATURA EN CAVAS DE MADURACIÓN DE QUESOS CLASSES DE CONTROLE DE UMIDADE RELATIVA E TEMPERATURA EM CAVAS DE MADURAÇÃO DE QUEIJOS RANGES OF CONTROL OF RELATIVE HUMIDITY AND TEMPERATURE IN CHAMBERS OF MATURATION OF CHEESES

    Directory of Open Access Journals (Sweden)

    DEYANIRA MUÑOZ MUÑOZ

    2010-06-01

    Full Text Available La humedad relativa y la temperatura en el interior de las cavas maduración del proceso de fabricación de quesos, son de interés a controlar porque determinan las características finales del producto. Las investigaciones se enfocan al control de estas dos variables en los rangos de diseño y operación recomendados, que permitan plantear sistemas de reducción de humedad más eficientes, que utilicen controles automáticos, semiautomáticos, manuales y artesanales. La metodología para establecer el rango de control fue: Se realizó un diseño completamente aleatorizado de efectos fijos. Se tomó como unidad experimental (Ue, la cava de maduración de queso, se establecieron 4 tratamientos con 17 repeticiones para operar la cava: mecheros y extractores encendidos; mecheros encendidos; extractores encendidos; mecheros y extractores apagados. Las variables de respuesta de interés en este estudio fueron la humedad relativa y la temperatura. Se tomó como referente de comparación los rangos de diseños recomendados en cavas de maduración: HR: 85 a 90% y T: 12 a 16 °C. El estudio se realizó en 12 días. En la sistematización de los datos se utilizó el paquete estadístico Social Packet Stadistic Sciences (SPSS versión libre 11.5. Los rangos de control encontrados para operar la cava de maduración de quesos fueron 93 a 100 % para humedad relativa (HR y 11 a 16°C para la temperatura (T, los cuales corresponde al tratamiento cuatro del diseño experimental. El límite superior de 100 % HR y 16°C de T, se definió como la condición más critica del proceso a ser controlada, en comparación con las recomendadas por diseño (HR= 85 %, T= 12°Cy las reportadas por otros investigadores (HR= 80 a 90 % HR, T= 12 °C. Mientras los valores que están fuera del rango definieron el proceso no controlado.A umidade relativa e temperatura no interior das cavas maduragáo do processo de fabricação de queijos são de interesse a controlar por que

  13. Rango de movilidad y resultados funcionales en tres diseños diferentes de artroplastia de rodilla primaria. Estudio Comparativo. [Range of motion and functional results in three different designs of total knee arthroplasty].

    Directory of Open Access Journals (Sweden)

    Juan Pablo Bonifacio

    2016-11-01

    Full Text Available Introducción: El objetivo de este trabajo  fue analizar los resultados funcionales y el rango de movi­miento entre tres grupos de pacientes con ar­troplastia total de rodilla: dos utilizando prótesis de alta flexión y el otro con un diseño convencional. Materiales y Métodos: 64 pacientes fueron operados con prótesis total de rodilla  Zimmer NexGen®, y 34 pacientes operados con Optetrack ®  de alta flexión. Luego de la exclusión de pacientes;  22 pacientes  (grupo A fueron tratados con diseño de alta flexión de Zimmer, 21 pacientes (grupo B tratados con prótesis Zimmer convencional, y 25 pacientes (Grupo C con artroplastia  Optetrack® PS. La evaluación funcional se realizó con el Knee Society Score, el Western Ontario and McMaster Universities osteoathritis index y la escala analógica visual. Resultados:  En el posoperatorio, el promedio de flexión máxima del grupo A subió de 99° a 113º, con un aumento promedio de 14º, en el grupo B de 106° a 118º con una ganancia promedio de 12º y en el grupo C de 110° a 111° siendo la ganancia de 1°. Los resultados funcionales evaluados con KSS y el WOMAC presentaron mejorías en los tres grupos. Conclusión: Las evaluaciones clínicas funcionales son favorables en los tres diseños  evaluados. Este estudio muestra que no hay diferencias significativas en la flexión final lograda, y resultados funcionales entre los dos primeros diseños entre sí, si siendo estos significativamente superiores al diseño del tercer grupo luego de un año de seguimiento.  Palabras Claves: Prótesis total de rodilla, prótesis de alta flexión, prótesis convencionales, rango de movilidad

  14. Identical transitions in the strongly deformed Sr-99 and Sr-100

    CERN Document Server

    Lhersonneau, G; Gabelmann, H; Kratz, K L

    2001-01-01

    The decay of the very neutron-rich nucleus Rb-100 has been studied by gamma-spectroscopy of on-line mass-separated samples. Schemes for beta-decay to Sr-100 and beta-n-decay to Sr-99 are presented. New sets of transitions in Sr-99 and Sr-100 with identical energies are observed. All identical bands so far observed in neutron-rich Sr isotopes obey a simple energy rule valid for even-even, odd-even and odd-odd bands.

  15. Finding Intercultural Business Communication Research Sites in Companies (Doing Research).

    Science.gov (United States)

    Driskill, Linda; Shaw, Peggy

    1994-01-01

    Describes important resources for discovering sites for communication research related to the North American Free Trade Agreement (NAFTA), to help identify appropriate companies and contact them. (SR)

  16. Level structure of 87Sr from the 86Sr(n, γ) and 86Sr(d, p) reactions

    Science.gov (United States)

    Winter, Ch.; Krusche, B.; Lieb, K. P.; Schmidt, H. H.; Von Egidy, T.; Hungerford, P.; Hoyler, F.; Börner, H. G.

    1986-12-01

    The γ-ray spectrum emitted after thermal neutron capture in 86Sr was studied at the ILL high flux reactor with pair- and intrinsic Ge spectrometers. 759 transitions were assigned to the reaction 86Sr(n, γ) 87Sr and 385 of them were placed into a 87Sr level scheme of 80 levels. This represents 90% of the observed intensity. The level energies were determined with a precision of better than 20 ppm; the neutron binding energy was determined to be 8428.16 (17)keV. In a second set of experiments high resolution particle spectra of the reactions 86Sr(d, p) 87Sr and 88Sr(d, t) 87Si were recorded at 20 MeV deuteron energy with the München Q3D spectrometer. These data were used to establish newly found levels and to differentiate between primary and secondary transitions in the (n, γ) data. The observed level densities and primary transition strengths are compared with statistical models.

  17. Decolorization of Methylene Blue by Ag/SrSnO3 Composites under Ultraviolet Radiation

    Directory of Open Access Journals (Sweden)

    Patcharanan Junploy

    2014-01-01

    Full Text Available SrSn(OH6 precursors synthesized by a cyclic microwave radiation (CMR process were calcined at 900°C for 3 h to form rod-like SrSnO3. Further, the rod-like SrSnO3 and AgNO3 in ethylene glycol (EG were ultrasonically vibrated to form rod-like Ag/SrSnO3 composites, characterized by X-ray diffraction (XRD, X-ray photoelectron spectroscopy (XPS, electron microscopy (EM, Fourier transform infrared (FTIR spectroscopy, and UV-visible analysis. The photocatalyses of rod-like SrSnO3, 1 wt%, 5 wt%, and 10 wt% Ag/SrSnO3 composites were studied for degradation of methylene blue (MB, C16H18N3SCl dye under ultraviolet (UV radiation. In this research, the 5 wt% Ag/SrSnO3 composites showed the highest activity, enhanced by the electron-hole separation process. The photoactivity became lower by the excessive Ag nanoparticles due to the negative effect caused by reduction in the absorption of UV radiation.

  18. ESTUDIO DEL EFECTO DE LA ISOTERMA EN EL PROCESO DE SÍNTESIS DEL COMPUESTO DE ESTRONCIO Sr4Al6O12SO4 POR REACCIÓN EN ESTADO SÓLIDO

    Directory of Open Access Journals (Sweden)

    José Rodríguez-García

    2012-01-01

    Full Text Available Se estudió el efecto de la isoterma en la síntesis del compuesto de estroncio Sr 4 Al 6 O 12 SO 4 por reacción en estado sólido. Se conformaron (100MPa gránulos a partir de la mezcla 3:3:1 molar de SrCO 3 , Al 2 O 3 y SrSO 4 , respectivamente. Las muestras fueron tratadas térmicamente a temperaturas de 800, 900, 1000, 1100 y 1200°C por periodos de 4, 6, 8 y 10 horas. Las muestras, en presentación de polvo y pastilla, fueron analizadas por ATG, ATD, DRX y MEB, desde temperatura ambiente ha sta los 1200°C. Los resultad os de análisis térmico señalan que el rango de formación del compuesto de estroncio Sr 4 Al 6 O 12 SO 4 es entre los 800 y 1200°C. Por otro lado, de acuerdo a los patrones de difr acción de rayos X, la formación del mismo se favorece al incrementarse la isoterma del tratamiento térmico. Existen dos fases meta-estables presentes durante el proceso antes mencionado, las mismas que son observadas en el MEB.

  19. A new dimension to the Sr isotope system - (88/86)Sr record of marine carbonates in the Phanerozoic

    Science.gov (United States)

    Vollstaedt, H.; Eisenhauer, A.; Krabbenhoeft, A.; Farkas, J.; Veizer, J.

    2009-12-01

    For the first time we extend and complete the application of the radiogenic Sr isotope system (87Sr/86Sr) with a simultaneous measurement of radiogenic and stable strontium (Sr) isotopes (δ(88/86)Sr[‰]=(88Sr/86Srsample/88Sr/86Sr(NBS987)-1)*1000). Taking Sr isotope fractionation into account this opens a new dimension for the Sr isotope system allowing to gain quantitative information about the Sr output from the ocean. Applying a 87Sr/84Sr-double spike we measured paired δ(88/86)Sr-87Sr/86Sr* ratios of Phanerozoic marine carbonates samples which were screened for diagenesis prior to the measurement. The 87Sr/86Sr* ratios are renormalized to δ(88/86)Sr=0‰ (88Sr/86Sr=8.375209) in order to be compatible to the radiogenic Sr isotope system values. Data reduction and denormalization follows an iterative algorithm by Krabbenhöft et al. (2009). External δ(88/86)Sr reproducibility based on an internal coral carbonate standard (JCp-1) corresponds to 0.008‰ (2SEM). Our data reveal that the δ(88/86)Sr values of Phanerozoic brachiopods and belemnites samples are in the range of modern marine carbonates (JCp-1 coral standard value: 0.192±0.008‰) but isotopically lighter than modern seawater (δ(88/86)Sr(IAPSO)= 0.385±0.007‰) being in the range between ~0.080‰ and ~0.370‰ (mean of 0.168). We observe a decrease in δ(88/86)Sr from Ordovician (0.200‰) to Silurian period (0.080‰) with a consequent increase in δ(88/86)Sr towards the upper Permian period. Highest values (~0.370‰) of δ(88/86)Sr are reached close to the Permian/Triassic boundary. This study examines the main factors that control δ(88/86)Sr on Phanerozoic timescale. It was found that temperature is not the main factor that drives δ(88/86)Sr of marine carbonates. Rather we suggest that the δ(88/86)Sr of Phanerozoic seawater is controlled by changes in the Sr fluxes in and out of the ocean. Modeling of our data allows a quantification of the Phanerozoic imbalance between the Sr input and

  20. Ab initio investigations of the strontium gallium nitride ternaries Sr 3GaN3 and Sr6GaN5: Promising materials for optoelectronic

    KAUST Repository

    Goumri-Said, Souraya

    2013-05-31

    Sr3GaN3 and Sr6GaN5 could be promising potential materials for applications in the microelectronics, optoelectronics and coating materials areas of research. We studied in detail their structural, elastic, electronic, optical as well as the vibrational properties, by means of density functional theory framework. Both of these ternaries are semiconductors, where Sr3GaN3 exhibits a small indirect gap whereas Sr6GaN5 has a large direct gap. Indeed, their optical properties are reported for radiation up to 40 eV. Charge densities contours, Hirshfeld and Mulliken populations, are reported to investigate the role of each element in the bonding. From the mechanical properties calculation, it is found that Sr6GaN5 is harder than Sr3GaN3, and the latter is more anisotropic than the former. The phonon dispersion relation, density of phonon states and the vibrational stability are reported from the density functional perturbation theory calculations. © 2013 IOP Publishing Ltd.

  1. Electronic parameters of Sr2M2O7 (M = V, Nb, Ta) and Sr-O chemical bonding

    DEFF Research Database (Denmark)

    Atuchin, Victor V.; Grivel, Jean-Claude; Zhang, Zhaoming

    2010-01-01

    on the formation of the Sr-O bonds. The chemical bonding effects were considered on the basis of our XPS results for Sr2Nb2O7 and Sr2Ta2O7 and the previously published structural and XPS data for other Sr-oxide compounds. A new empirical relationship between Δ(O-Sr) and L(Sr-O) was obtained. Possible applications...

  2. Maxdose-SR and popdose-SR routine release atmospheric dose models used at SRS

    Energy Technology Data Exchange (ETDEWEB)

    Jannik, G. T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Trimor, P. P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-07-28

    MAXDOSE-SR and POPDOSE-SR are used to calculate dose to the offsite Reference Person and to the surrounding Savannah River Site (SRS) population respectively following routine releases of atmospheric radioactivity. These models are currently accessed through the Dose Model Version 2014 graphical user interface (GUI). MAXDOSE-SR and POPDOSE-SR are personal computer (PC) versions of MAXIGASP and POPGASP, which both resided on the SRS IBM Mainframe. These two codes follow U.S. Nuclear Regulatory Commission (USNRC) Regulatory Guides 1.109 and 1.111 (1977a, 1977b). The basis for MAXDOSE-SR and POPDOSE-SR are USNRC developed codes XOQDOQ (Sagendorf et. al 1982) and GASPAR (Eckerman et. al 1980). Both of these codes have previously been verified for use at SRS (Simpkins 1999 and 2000). The revisions incorporated into MAXDOSE-SR and POPDOSE-SR Version 2014 (hereafter referred to as MAXDOSE-SR and POPDOSE-SR unless otherwise noted) were made per Computer Program Modification Tracker (CPMT) number Q-CMT-A-00016 (Appendix D). Version 2014 was verified for use at SRS in Dixon (2014).

  3. Groundwater Paleohydrology Using Microsample Sr Isotopic Data

    Science.gov (United States)

    Farmer, G.; Fritz, D. E.

    2003-12-01

    Physical microsampling of silicate alteration phases produced during past episodes of groundwater flow, combined with Sr isotopic data, can be used to determine the age of the alteration phases and to define paleogroundwater flow paths. For example, we have obtained microsamples of secondary adularia present in the K-metasomatized, mid-Tertiary Lemitar Tuff in southern New Mexico. The microsamples (~25 micrograms) yield a Rb-Sr "errochron" (MSWD~29) of 6.3 Ma, and an 87Sr/86Sr (6 Ma)=0.7206. The adularia isotopic compositions are considerably higher than those determined for igneous plagioclase and sanidine phenocrysts in the same tuff (0.710), or for the tuff matrix, and indicate that the radiogenic Sr incorporated into the adularia was introduced to the tuff during alteration. Na-Ca sulfates present in playa deposits in the Tertiary Popotosa Formation have Sr isotopic compositions similar to the unaltered tuffs, and not the adularia, and suggest that the fluids responsible for the K-metasomatism of the Lemitar Tuff were not down-flowing saline fluids originating from playa lakes in the Popotosa Basin. Instead, we argue that the fluids were generated during topographically driven flow of meteoric waters through high 87Sr/86Sr Precambrian basement-cored horsts generated during early Basin and Range extension in this area. These data illustrate the utility of such Sr isotopic information in investigations of paleogroundwater flow and we are currently extending the technique to study the origin of the multiple low-T groundwater flow events recorded in the various secondary silicate, sulfate, and carbonate phases present in the Late Paleozoic Fountain Formation in northern Colorado.

  4. Examination of SR101 shipping packages

    Energy Technology Data Exchange (ETDEWEB)

    Daugherty, W. L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-03-01

    Four SR101 shipping packages were removed from service and provided for disassembly and examination of the internal fiberboard assemblies. These packages were 20 years old, and had experienced varying levels of degradation. Two of the packages were successfully disassembled and fiberboard samples were removed from these packages and tested. Mechanical and thermal property values are generally comparable to or higher than baseline values measured on fiberboard from 9975 packages, which differs primarily in the specified density range. While baseline data for the SR101 material is not available, this comparison with 9975 material suggests that the material properties of the SR101 fiberboard have not significantly degraded.

  5. Spectroscopy of 88Sr with the 87Sr(n, γ) and 87Sr(d, p) reactions

    Science.gov (United States)

    Winter, Ch.; Krusche, B.; Lieb, K. P.; Weber, T.; Hlawatsch, G.; Von Egidy, T.; Hoyler, F.

    1987-10-01

    The γ-ray spectrum emitted after thermal neutron capture in 87Sr was studied at the ILL high flux reactor with pair- and intrinsic Ge-spectrometers. 661 transitions were assigned to the reaction 87Sr(n, γ) 88Sr and 205 of them were placed into a 88Sr level scheme of 47 levels. This represents 88% of the observed intensity. The level energies were determined with a precision of better than 20 ppm; the neutron binding energy was determined as 11 112.69 (22) keV. To aid the analysis high resolution particle spectra of the reaction 87Sr(d, p) 88Sr were measured at 20 MeV deuteron energy with the Munich Q3D spectrometer. 85 states were observed with this reaction. The data helped to establish newly found levels and to differentiate between primary and secondary transitions in the (n, γ) data. The observed level densities and primary transition strengths are compared with statistical model predictions and non-statistical effects are discussed.

  6. Efecto del estiramiento estático de 15, 30 y 60 segundos sobre el rango de movimiento de la flexión de cadera con rodilla extendida

    Directory of Open Access Journals (Sweden)

    Claudia Lucía Ariza-García

    2014-06-01

    Full Text Available Objetivo: Evaluar el efecto de tres duraciones de estiramiento estático pasivo, 15, 30 y 60 segundos (s para aumentar el rango de movimiento de la flexión de cadera (ROM-FC. Metodología: Ensayo Clínico Controlado Aleatorizado. Nueve estudiantes mujeres (21,7 ± 4,3 años fueron asignadas aleatoriamente a tres grupos, 15 (G15, 30 (G30 y 60 (G60 s; n = 3 en cada grupo. El estiramiento de la musculatura isquitotibial se realizó en decúbito supino, máxima flexión de cadera, rodilla extendida y dorsiflexión de pie con ayuda de una banda elástica; dos veces consecutivas en ambos miembros inferiores, tres veces/semana, por tres semanas. El resultado principal fue el cambio del ROM-FC izquierda y derecha al finalizar la intervención. Se usó la prueba t de student y el análisis ANOVA. Resultados:  Las diferencias entre evaluaciones en G15 y G30 fueron estadísticamente significativas para el miembro inferior derecho. No se encontraron diferencias significativas en el grupo G60 del hemicuerpo derecho ni en grupo alguno del hemicuerpo izquierdo. Tampoco para el aumento de ROM-FC entre los tres grupos ni entre hemicuerpos. Conclusión: El estiramiento estático pasivo de 15 y 30 s de duración fue efectivo para aumentar el ROM-FC derecho. Se requieren futuros estudios con un tamaño de muestra adecuado para detectar diferencias en el aumento del ROM-FC según duración del estiramiento y hemicuerpos.

  7. Efecto del estiramiento estático de 15, 30 y 60 segundos sobre el rango de movimiento de la flexión de cadera con rodilla extendida

    Directory of Open Access Journals (Sweden)

    Claudia Lucía Ariza-García

    2016-08-01

    Full Text Available Objetivo: Evaluar el efecto de tres duraciones de estiramiento estático pasivo, 15, 30 y 60 segundos (s para aumentar el rango de movimiento de la flexión de cadera (ROM-FC. Metodología: Ensayo Clínico Controlado Aleatorizado. Nueve estudiantes mujeres (21,7 ± 4,3 años fueron asignadas aleatoriamente a tres grupos, 15 (G15, 30 (G30 y 60 (G60 s; n = 3 en cada grupo. El estiramiento de la musculatura isquitotibial se realizó en decúbito supino, máxima flexión de cadera, rodilla extendida y dorsiflexión de pie con ayuda de una banda elástica; dos veces consecutivas en ambos miembros inferiores, tres veces/semana, por tres semanas. El resultado principal fue el cambio del ROM-FC izquierda y derecha al finalizar la intervención. Se usó la prueba t de student y el análisis ANOVA. Resultados:  Las diferencias entre evaluaciones en G15 y G30 fueron estadísticamente significativas para el miembro inferior derecho. No se encontraron diferencias significativas en el grupo G60 del hemicuerpo derecho ni en grupo alguno del hemicuerpo izquierdo. Tampoco para el aumento de ROM-FC entre los tres grupos ni entre hemicuerpos. Conclusión: El estiramiento estático pasivo de 15 y 30 s de duración fue efectivo para aumentar el ROM-FC derecho. Se requieren futuros estudios con un tamaño de muestra adecuado para detectar diferencias en el aumento del ROM-FC según duración del estiramiento y hemicuerpos.

  8. Radiogenic and stable Sr isotope ratios (87Sr/86Sr, δ88/86Sr) as tracers of riverine cation sources and biogeochemical cycling in the Milford Sound region of Fiordland, New Zealand

    Science.gov (United States)

    Andrews, M. Grace; Jacobson, Andrew D.; Lehn, Gregory O.; Horton, Travis W.; Craw, Dave

    2016-01-01

    This study reports radiogenic Sr isotope ratios (87Sr/86Sr), stable Sr isotope ratios (δ88/86Sr), and major ion concentrations for river, rock, sediment, soil, and plant samples collected from the Cleddau and Hollyford catchments in the Milford Sound region of Fiordland, New Zealand. The catchments primarily drain gabbro, but some tributaries access limestone and volcanogenic sediments. The goal of the study was to understand controls on riverine δ88/86Sr values in a landscape with multiple factors that may influence chemical weathering, including dense vegetation, high rainfall, and abundant, freshly-eroded Holocene fluvio-glacial and landslide debris. Rivers draining gabbro have higher δ88/86Sr values than bedrock, by as much as ∼0.14‰, and the δ88/86Sr values strongly correlate with molar Ca/Sr ratios (R2 = 0.69). Leaching of rocks and sediment reveals no evidence for the preferential dissolution of minerals having high δ88/86Sr values and Ca/Sr ratios. In-stream Sr isotope fractionation seems unlikely because comparison against 87Sr/86Sr and Ca/Sr ratios demonstrates that riverine δ88/86Sr values conservatively trace water-mass mixing. The riverine data are best explained by the input of soil water, which is distinct from potential bedrock end-members (i.e., silicates and carbonates) based on δ88/86Sr but indistinguishable in terms of Ca/Sr and 87Sr/86Sr. While strontium isotope fractionation during secondary mineral formation and pedogenesis is possible, clay mineral formation is minor and most soils are poorly developed. Instead, soil water δ88/86Sr values more likely reflect plant uptake. Plant samples yielded a wide range of δ88/86Sr values, but on average, they are lower than those for bedrock, consistent with the expectation that plants preferentially incorporate lighter Sr isotopes. Mass-balance constraints, together with 87Sr/86Sr ratios, indicate that soil water δ88/86Sr values are ∼0.30‰ higher than bedrock δ88/86Sr values, and

  9. Preparation of Compensation Ions Codoped SrTiO3:Pr3+ Red Phosphor with the Sol-Gel Method and Study of Its Luminescence Enhancement Mechanism

    Directory of Open Access Journals (Sweden)

    Dan Guo

    2014-01-01

    Full Text Available SrTiO3:Pr3+ is the most representative titanate matrix red phosphor for field emission display (FED. The red luminous efficiency of SrTiO3:Pr3+ will be greatly improved after the compensation ions codoping, so SrTiO3:Pr3+ red phosphor has been a research focus at home and abroad. SrTiO3:Pr3+, SrTiO3:Pr3+, Mg2+, and SrTiO3:Pr3+, Al3+ phosphors are synthesized by a new sol-gel method. Crystal structure, spectral characteristics, and luminescence enhancement mechanism of the sample were studied by XRD and PL spectra. The results showed that after co-doped, SrTiO3:Pr3+ phosphor is single SrTiO3 cubic phase, the main emission front is located at 614 nm, corresponding to Pr3+ ions 1D2→3H4 transition emission. SrTiO3:Pr3+, Mg2+ and SrTiO3:Pr3+, Al3+ phosphor luminescence intensity is enhanced, but the main luminescence mechanism is not changed. Acceptor impurity x = Mg2+, Al3+ will replace Ti bit after being doped into the crystal lattice to form XTi- charge compensation corresponding defect centers PrSr+ to reduce the demand of Sr2+ or Ti3+ vacancy. While Sr-doped Pr will make lattice distortion and transition energy of 4f-5d is very sensitive to crystal electric field changes around Pr atom. Doping different impurities will make electric field distribution around the icon have a different change. It increases energy transfer of 4f-5d transition and improves the luminous intensity of SrTiO3:Pr3+ red phosphor.

  10. Paired Sr isotope (87Sr/86Sr, δ88/86Sr) systematic of pore water profiles: A new perspective in marine weathering and seepage studies

    OpenAIRE

    Liebetrau, Volker; Haeckel, Matthias; Eisenhauer, Anton; Scholz, Florian; Hensen, Christian; Reitz, Anja

    2011-01-01

    The simultaneous and independent determination of the radiogenic (87Sr/86Sr) and the fractionation reflecting stable (!88/86Sr) Sr isotope ratio on pore waters, sediments and precipitates (e.g. carbonates and sulfates) opens a new perspective in the field of submarine weathering and Sr contribution to the ocean chemistry. Four initial case studies covering (1.) CO2 seeps of the Okinawa Trough (OT), (2.) mud volcanoes (MV) and mounds in the Gulf of Cadiz (GoC) and the (...

  11. First-principle calculations of the thermal properties of SrTiO3 and SrO(SrTiO3)n (n=1,2)

    Science.gov (United States)

    Lu, Yanli; Jia, Dewei; Gao, Feng; Hu, Tingting; Chen, Zheng

    2015-01-01

    The thermal properties of SrTiO3 and SrO(SrTiO3)n (n=1,2) with layered perovskite structure are analyzed using the Debye-Grüneisen model combined with ab initio calculations. The thermal expansion coefficient, specific heat at constant pressure CP and specific heat at constant volume CV, adiabatic bulk modulus BS and isothermal bulk modulus BT, entropy, and Debye temperature are investigated. At temperatures higher than 550 °C, the thermal expansion coefficient and the discrepancies between CP and CV, as well as that between BS and BT, of Sr3Ti2O7 increase the fastest as the temperature rises, followed by those of Sr2TiO4, and those of SrTiO3 increase the slowest. The bulk module and Debye temperature of Sr2TiO4, Sr3Ti2O7, and SrTiO3 increase with decreasing SrO/SrTiO3 ratio at 0 K. With increasing temperature, however, the bulk modulus and Debye temperature of Sr3Ti2O7 both rapidly decrease and even fall below those of Sr2TiO4 when the temperature is higher than specific values. We also analyzed the thermal properties of these three compounds in the pressure range from 0 GPa to 16 GPa at 300 K.

  12. Investigation of a dynamic seawater intrusion event using strontium isotopes (87Sr/86Sr)

    DEFF Research Database (Denmark)

    Jørgensen, Niels Oluf; Andersen, Martin S.; Engesgaard, Peter Knudegaard

    2008-01-01

    isotopes reflect recharge conditions and mixing between groundwater and seawater. The 87Sr/86Sr isotope ratios are controlled by aquifer matrix chemistry. The 87Sr/86Sr ratio distribution and Sr content reveal a ternary mixing system in the shallow aquifer, encompassing brackish seawater, fresh shallow...... of Palaeocene (Danian) limestone. Stable isotopes (18O and 2H), strontium isotopes (87Sr/86Sr) and the elements Sr and Cl were measured to delineate the mixing of seawater and groundwater in the shallow aquifer and to determine the contribution from different water sources along the flow paths. The stable...... groundwater and deep groundwater from the underlying limestone aquifer as end-members. A mixing analysis is performed using the Cl contents and the 87Sr/86Sr ratios. The mixing analysis indicates a zone with leakage of deep groundwater from the limestone aquifer into the lower part of the shallow sandy...

  13. Diagnostic and co-dominant PCR markers for wheat stem rust resistance genes Sr25 and Sr26.

    Science.gov (United States)

    Liu, Sixin; Yu, Long-Xi; Singh, Ravi P; Jin, Yue; Sorrells, Mark E; Anderson, James A

    2010-02-01

    Wheat stem rust, caused by Puccinia graminis f. sp. tritici, is one of the most destructive diseases of wheat. A new race of the pathogen named TTKSK (syn. Ug99) and its derivatives detected in East Africa are virulent to many designated and undesignated stem rust resistance genes. The emergence and spread of those races pose an imminent threat to wheat production worldwide. Genes Sr25 and Sr26 transferred into wheat from Thinopyrum ponticum are effective against these new races. DNA markers for Sr25 and Sr26 are needed to pyramid both genes into adapted germplasm. The previously published dominant markers Gb for Sr25 and Sr26#43 for Sr26 were validated with eight wheat lines with or without Sr25 or Sr26. We tested six published STS (sequence tagged site) markers amplifying diagnostic bands of Th. ponticum. Marker BF145935 consistently amplified well and can be used as a co-dominant marker for Sr25. Among 16 STS markers developed from wheat ESTs mapped to deletion bin 6AL8-0.90-1.00, none was co-dominant for tagging Sr26. However, five 6A-specific markers were identified. Multiplex PCR with marker Sr26#43 and 6A-specific marker BE518379 can be used as a co-dominant marker for Sr26. The co-dominant markers for Sr25 and Sr26 were validated with 37 lines with known stem rust resistance genes. A diverse set of germplasm consisting 170 lines from CIMMYT, China, USA and other counties were screened with the co-dominant markers for Sr25 and Sr26. Five lines with the diagnostic fragment for Sr25 were identified, and they all have 'Wheatear' in their pedigrees, which is known to carry Sr25. None of the 170 lines tested had Sr26, as expected.

  14. 878787Sr/868686Sr anomalies in Late Cretaceous-Early Tertiary ...

    Indian Academy of Sciences (India)

    Cretaceous–Tertiary boundary; strontium isotope; biotic turnover; sea level changes. .... or volcanic activity in Godavari basin could have ...... climate and the. 87. Sr/. 86. Sr ratio of seawater; Earth Planet. Sci. Lett. 188 459–474. Donovan A D, Baum G R, Blechschmidt L, Loutit T S,. Pflum C E and Vail P R 1988 Sequence ...

  15. Photosynthetic biomineralization of radioactive Sr via microalgal CO2 absorption.

    Science.gov (United States)

    Lee, Seung Yeop; Jung, Kwang-Hwan; Lee, Ju Eun; Lee, Keon Ah; Lee, Sang-Hyo; Lee, Ji Young; Lee, Jae Kwang; Jeong, Jong Tae; Lee, Seung-Yop

    2014-11-01

    Water-soluble radiostrontium ((90)Sr) was efficiently removed as a carbonate form through microalgal photosynthetic process. The immobilization of soluble (90)Sr radionuclide and production of highly-precipitable radio-strontianite ((90)SrCO3) biomineral are achieved by using Chlorella vulgaris, and the biologically induced mineralization drastically decreased the (90)Sr radioactivity in water to make the highest (90)Sr removal ever reported. The high-resolution microscopy revealed that the short-term removal of soluble (90)Sr by C. vulgaris was attributable to the rapid and selective carbonation of (90)Sr together with the consumption of dissolved CO2 during photosynthesis. A small amount of carbonate in water could act as Sr(2+) sinks through the particular ability of the microalga to make the carbonate mineral of Sr stabilized firmly at the surface site. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Dielectric Relaxation Behavior of Bismuth Doped (Ba0.2Sr0.8 TiO3 Ceramics

    Directory of Open Access Journals (Sweden)

    Baptista, J. L.

    1999-12-01

    Full Text Available The dielectric properties of bismuth doped (Ba0.2Sr0.8TiO3 ceramics are investigated. The temperature dependence of the dielectric permittivity and loss factor were measured from 102 to 106Hz in the temperature range 12-320K. As the amount of Bi increases, the ferroelectric-paraelectric phase transition gets diffused and relaxed. In addition to this ferroelectric-paraelectric phase transition, other two sets of dielectric anomalies, located at 50-100K and 200-300K respectively, are also found. The possible relaxation mechanisms are briefly discussed.Las propiedades dieléctricas de cerámicos dopados con bismuto son investigadas. La dependencia con la temperatura de la permitividad dieléctrica y el factor de pérdidas se midieron entre 02 y 106Hz en el rango de temperatura 12-320K. Con el aumento del contenido en Bi, la transición de fase ferroeléctrica-paraléctrica se hace difusa y reloja. Junto a esta transición de fase los conjuntos de anomalías dieléctricas, localizados a 50-100k y 200-300k respectivamente, también se encontraron. Se discute brevemente los posibles mecanismos de relajación.

  17. OBTENCIÓN DE BACTERIAS BIOTRANSFORMADORAS DE CARBÓN DE BAJO RANGO A PARTIR DE MICROHÁBITATS CON PRESENCIA DE RESIDUOS CARBONOSOS Obtaining Low Rank Coal Biotransforming Bacteria from Microhabitats Enriched with Carbonaceos Residues

    Directory of Open Access Journals (Sweden)

    NELSON VALERO VALERO

    2012-05-01

    Full Text Available Se aislaron bacterias con actividad biotransformadora de carbón de bajo rango (CBR a partir de muestras ambientales con presencia de residuos de carbón en la mina "El Cerrejón". Se aislaron 75 morfotipos bacterianos de los cuales 32 presentaron crecimiento en medio sólido mínimo de sales con carbón a 5 %. Se diseño un protocolo para la selección de los morfotipos con mayor actividad biotransformadora de CBR, el protocolo incluye el aislamiento en un medio selectivo con CBR en polvo, pruebas cualitativas y cuantitativas de solubilización de CBR en medios sólidos y líquido. El mecanismo de solubilización en las cepas que producen mayores valores de sustancias húmicas (SH estuvo asociado a cambios de pH en el medio, probablemente por la producción de sustancias alcalinas extracelulares. El mayor número de aislamientos y los aislamientos con mayor actividad solubilizadora sobre el CBR provienen de lodo con alto contenido de residuos de carbón y las rizósferas de Typha domingensis y Cenchrus ciliaris que crecen sobre sedimentos mezclados con partículas de carbón, este resultado sugiere que la obtención y capacidad de solubilización de CBR por parte de bacterias puede estar relacionada con el microhábitat donde se desarrollan las poblaciones.Bacteria capable of low rank coal (LRC biotransform were isolated from environmental samples altered with coal in the mine "The Cerrejon". A protocol was designed to select strains more capable of LRC biotransform, the protocol includes isolation in a selective medium with LRC powder, qualitative and quantitative tests for LRC solubilization in solid and liquid culture medium. Of 75 bacterial strains isolated, 32 showed growth in minimal salts agar with 5 % carbon. The strains that produce higher values of humic substances (HS have a mechanism of solubilization associated with pH changes in the culture medium, probably related to the production of extracellular alkaline substances by bacteria

  18. Facile Synthesis of SrCO3-Sr(OH2/PPy Nanocomposite with Enhanced Photocatalytic Activity under Visible Light

    Directory of Open Access Journals (Sweden)

    Alfredo Márquez-Herrera

    2016-01-01

    Full Text Available Pyrrole monomer was chemically polymerized onto SrCO3-Sr(OH2 powders to obtain SrCO3-Sr(OH2/polypyrrole nanocomposite to be used as a candidate for photocatalytic degradation of methylene blue dye (MB. The material was characterized by Fourier transform infrared (FTIR spectroscopy, UV/Vis spectroscopy, and X-ray diffraction (XRD. It was observed from transmission electronic microscopy (TEM analysis that the reported synthesis route allows the production of SrCO3-Sr(OH2 nanoparticles with particle size below 100 nm which were embedded within a semiconducting polypyrrole matrix (PPy. The SrCO3-Sr(OH2 and SrCO3-Sr(OH2/PPy nanocomposites were tested in the photodegradation of MB dye under visible light irradiation. Also, the effects of MB dye initial concentration and the catalyst load on photodegradation efficiency were studied and discussed. Under the same conditions, the efficiency of photodegradation of MB employing the SrCO3-Sr(OH2/PPy nanocomposite increases as compared with that obtained employing the SrCO3-Sr(OH2 nanocomposite.

  19. Climate and climate-related issues for the safety assessment SR-Site

    Energy Technology Data Exchange (ETDEWEB)

    2010-12-15

    The purpose of this report is to document current scientific knowledge on climate and climate-related conditions, relevant to the long-term safety of a KBS-3 repository, to a level required for an adequate treatment in the safety assessment SR-Site. The report also presents a number of dedicated studies on climate and selected climate-related processes of relevance for the assessment of long term repository safety. Based on this information, the report presents a number of possible future climate developments for Forsmark, the site selected for building a repository for spent nuclear fuel in Sweden (Figure 1-1). The presented climate developments are used as basis for the selection and analysis of SR-Site safety assessment scenarios in the SR-Site main report /SKB 2011/. The present report is based on research conducted and published by SKB as well as on research reported in the general scientific literature

  20. 87Sr/ 86Sr, 143Nd/ 144Nd and REEs in Silurian phosphatic fossils

    Science.gov (United States)

    Bertram, C. J.; Elderfield, H.; Aldridge, R. J.; Conway Morris, S.

    1992-09-01

    The feasibility of using the chemistry of phosphatic fossil material to trace palaeo-seawater composition for the Silurian has been evaluated. Contrary to Recent material, fossil fish are shown to be unreliable for Sr isotope stratigraphy. Conodonts, however, may be used by employing 0.2M HNO 3 dissolution, except for samples showing degrees of thermal maturation greater than colour alteration index (CAI) values of 2.5. Samples from the same stratigraphic levels from the U.K., Czechoslovakia, Gotland and the U.S.A. gave similar 87Sr/ 86Sr ratios, suggesting that they have recorded the original seawater value. Significant inter-specific differences occur in REE concentrations and Nd isotopic compositions of conodont elements, and Ce and Eu anomalies vary with REE content. This suggests that artefacts are introduced at the same time that large amounts of REEs are incorporated into the apatite. Preliminary results for the Sr isotopic composition of Silurian seawater are presented. Values are generally lower than previously suggested, showing an increase in 87Sr/ 86Sr from ˜ 0.70825 at 435 Ma rising to ˜ 0.70875 at 418 Ma and levelling off in the Late Silurian. The overall rate of increase in seawater ratio is about2-3 × 10 -5 Ma -1 and can be accounted for by the widespread decrease in volcanism compared with the Ordovician; a proportionally greater flux of Sr to the oceans from continental erosion of only ˜ 10% would account for the long-term increase in seawater 87Sr/ 86Sr ratio throughout the Silurian.

  1. FEP report for the safety assessment SR-Site

    Energy Technology Data Exchange (ETDEWEB)

    2010-12-15

    This report documents the analysis and processing of features, events and processes, FEPs, that has been carried out within the safety assessment SR-Site, and forms an important part of the reporting of the project. The main part of the work was conducted within the earlier safety assessment SR-Can, which was a preparatory stage for the SR-Site assessment. The overall objective of the FEP analysis and processing in both SR-Can and SR-Site included development of a database of features, events and processes, an SKB FEP database, in a format that facilitates both a systematic analysis of FEPs and documentation of that FEP analysis, as well as facilitating revisions and updates to be made in connection with new safety assessments. The primary objective in SR-Site was to establish an SR-Site FEP catalogue within the framework of the SKB FEP database. This FEP catalogue was required to contain all FEPs that needed to be handled in SR-Site and is an update of the corresponding SR-Can FEP catalogue that was established for the SR-Can assessment. The starting point for the handling of FEPs in SR-Site was the SR-Can version of the SKB FEP database and associated SR-Can reports. The SR-Can version of the SKB FEP database includes the SR-Can FEP catalogue, as well as the sources for the identification of FEPs in SR-Can, namely the SR 97 processes and variables, Project FEPs in the NEA International FEP database version 1.2 and matrix interactions in the Interaction matrices developed for a deep repository of the KBS-3 type. Since the completion of the FEP work within SR-Can, an updated electronic version, version 2.1, of the NEA FEP database has become available. Compared with version 1.2 of the NEA FEP database, version 2.1 contains FEPs from two more projects. As part of SR-Site, all new Project FEPs in version 2.1 of the NEA FEP database have been mapped according to the methodology adopted in SR-Can resulting in an SR-Site version of the SKB FEP database. The SKB FEP

  2. A high 87Sr 86Sr mantle source for low alkali tholeiite, northern Great Basin

    Science.gov (United States)

    Mark, R.K.; Lee, Hu C.; Bowman, H.R.; Asaro, F.; McKee, E.H.; Coats, R.R.

    1975-01-01

    Olivine tholeiites, the youngest Tertiary units (about 8-11 m.y. old) at five widely spaced localities in northeastern Nevada, are geologically related to the basalts of the Snake River Plain, Idaho, to the north and are similar in major element and alkali chemistry to mid-ocean ridge basalts (MORB) and island arc tholeiites. The measured K (1250-3350 ppm), Rb (1??9-6??2 ppm) and Sr (140-240 ppm) concentrations overlap the range reported for MORB. Three of the five samples have low, unfractionated rare earth element (REE) patterns, the other two show moderate light-REE enrichment. Barium concentration is high and variable (100-780 ppm) and does not correlate with the other LIL elements. The rocks have 87Sr/86Sr = 0??7052-0??7076, considerably higher than MORB (~0??702-0??703). These samples are chemically distinct (i.e. less alkalic) from the olivine tholeiites from the adjacent Snake River Plain, but their Sr isotopic compositions are similar. They contain Sr that is distinctly more radiogenic than the basalts from the adjacent Great Basin. About 10 b.y. would be required for the mean measured Rb/Sr (~ 0??02) of these samples to generate, in a closed system, the radiogenic Sr they contain. The low alkali content of these basalts makes crustal contamination an unlikely mechanism. If the magma is uncontaminated, the time-averaged Rb/Sr of the source material must have been ~0??04. A significant decrease in Rb/Sr of the source material (a factor 2??) thus most probably occurred in the relatively recent (1??09 yr) past. Such a decrease of Rb/Sr in the mantle could accompany alkali depletion produced by an episode of partial melting and magma extraction. In contrast, low 87Sr 86Sr ratios indicate that the source material of the mid-ocean ridge basalts may have been depleted early in the Earth's history. ?? 1975.

  3. Analysis of coupled Sr/Ca and 87Sr/ 86Sr variations in enamel using laser-ablation tandem quadrupole-multicollector ICPMS

    Science.gov (United States)

    Balter, Vincent; Telouk, Philippe; Reynard, Bruno; Braga, José; Thackeray, Francis; Albarède, Francis

    2008-08-01

    We present in this study results obtained with a laser-ablation coupled with both a quadrupole and a multi-collector ICPMS. The simultaneous in situ Sr/Ca and 87Sr/ 86Sr measurements along growth profiles in enamel allows the concomitant diet and migration patterns in mammals to be reconstructed. Aliquots of the powdered international standard NIST "SRM1400 Bone Ash" with certified Sr and Ca contents, was sintered at high pressure and temperature and was adopted as the reference material for external reproducibility and calibration of the results. A total of 145 coupled elemental and isotopic measurements of herbivores enamel from the Kruger National Park, South Africa, gives intra-tooth Sr/Ca and 87Sr/ 86Sr variations that are well larger than external reproducibility. Sr/Ca profiles systematically decrease from the dentine-enamel junction to the outer enamel whereas 87Sr/ 86Sr profiles exhibit variable patterns. Using a simple geometric model of hypsodont teeth growth, we demonstrate that a continuous recording of the 87Sr/ 86Sr variations can be reconstructed in the tooth length axis. This suggests that the mobility of a mammal can be reconstructed over a period of more than a year with a resolution of a ten of days, by sampling enamel along growth profiles. Our geometric model of hypsodont teeth growth predicts that an optimal distance between two successive profiles is equal to the enamel thickness. However, this model does not apply to the Sr/Ca signal which is likely to be altered during the enamel maturation stage due to differential maturation processes along enamel thickness. Here, the observed constant decreases of the Sr/Ca ratios in the ungulates of Kruger National Park suggests that they did not changed of diet, while some of them were migrating.

  4. Research

    African Journals Online (AJOL)

    ebutamanya

    2015-03-02

    Mar 2, 2015 ... Using a critical leadership theory framework, we conducted a qualitative ... or basic science research career (Socio-Behavioral Research, ... AITRP was to develop HIV research leaders at the University of ..... Wellcome-Trust.

  5. Radionuclide transport report for the safety assessment SR-Site

    Energy Technology Data Exchange (ETDEWEB)

    2010-12-15

    This document compiles radionuclide transport calculations of a KBS-3 repository for the safety assessment SR-Site. The SR-Site assessment supports the licence application for a final repository at Forsmark, Sweden

  6. X-ray instrumentation for SR beamlines

    CERN Document Server

    Kovalchuk, M V; Zheludeva, S I; Aleshko-Ozhevsky, O P; Arutynyan, E H; Kheiker, D M; Kreines, A Y; Lider, V V; Pashaev, E M; Shilina, N Y; Shishkov, V A

    2000-01-01

    The main possibilities and parameters of experimental X-ray stations are presented: 'Protein crystallography', 'X-ray structure analysis', 'High-precision X-ray optics', 'X-ray crystallography and material science', 'X-ray topography', 'Photoelectron X-ray standing wave' that are being installed at Kurchatov SR source by A.V. Shubnikov Institute of Crystallography.

  7. Investidura como Doctor Sr. D. Luigi Ferrajoli

    OpenAIRE

    Ferrajoli, Luigi

    2009-01-01

    ÍNDICE: Laudatio Prof. Dr. D. Luis Prieto Sanchís Lección Magistral: La democracia política y su crisis actual Prof. Dr. D. Luigi Ferrajoli Salutación Excmo. Sr. Rector Magnífico, D. Ernesto Martínez Ataz Galeria fotográfica

  8. Diferencias de género en percepción visual de rango de color y profundidad Genre Differences on Visual Perception of Color Range and Depth of Field

    Directory of Open Access Journals (Sweden)

    Espinosa Paola

    2003-12-01

    Full Text Available La percepción visual es el resultado de la integración de varios aspectos relacionados con el objeto observado y su entorno. En este estudio se valoró, el impacto de la forma tridimensional sobre la percepción de color y el ángulo con respecto al plano horizontal de varios objetos similares sobre la percepción de profundidad en hombres y mujeres jóvenes. Para determinar el impacto de la forma sobre la percepción del color se utilizaron dos cajas negras, en cada una de las cuales se dispuso un panel coloreado la mitad de fucsia y la otra de blanco, plegado de manera cóncava o convexa para alterar el efecto cromático percibido. Para determinar el impacto de la distribución espacial de palillos de madera sobre la capacidad de determinar la profundidad de dicho espacio, se hicieron cuatro experimentos diferentes en los cuales se variaba el ángulo de los palillos con respecto al plano horizontal y se valoró la profundidad percibida. Las variables tenidas en cuenta fueron edad, género y presencia/ausencia de defectos visuales para cada observador. Los resultados obtenidos muestran que hay aspectos de la percepción visual que dependen del género. Si bien la forma tridimensional del objeto afectó la percepción de color en ambos grupos, las mujeres percibieron estas diferencias en un rango de color mayor, mientras que la variación del ángulo de varios objetos produce diferencias en la percepción de la profundidad que se asocian con el género.Visual perception is the result of the integration of various related factors of the observed object and its environment. In this study we evaluated the impact of tridimensional form on color perception and the angle from the horizontal plane of a set of similar objets on the depth of field perception between young men and women. A panel half magenta and half white placed at the end of a black box, folded either concaved or convexed to alter the chromatic effect perceived were used to determine

  9. Vínculos urbano-rurales y construcción de nuevas territorialidades en asentamientos de rango menor Urban-rural linkages and the rise of new territorialities on lower rank settlements

    Directory of Open Access Journals (Sweden)

    Guillermina Jacinto

    2012-01-01

    Full Text Available La homogeneización productiva ha trastocado los procesos de construcción territorial induciendo cambios en la naturaleza, intensidad y direccionalidad de los vínculos urbano-rurales en región pampeana. La creación de nuevas articulaciones y/o la redefinición de las interacciones preexistentes involucran dimensiones funcionales, institucionales y espaciales, dando origen a formas específicas de resolución territorial. A partir de enfoques superadores de las aproximaciones sectoriales y dualistas intrínsecas al paradigma de la modernización, que han impregnado la interpretación de procesos de construcción territorial a partir de la oposición "campo-ciudad", se propone la indagación a partir de la convergencia de macroprocesos que trastocan las trayectorias territoriales, al tiempo que renuevan la naturaleza de los vínculos urbano-rurales [avance de la pluriactividad, emergencia de nuevos actores y usos del suelo en los espacios rurales, urbanización difusa]. Dentro de esta perspectiva, los asentamientos de rango menor en región pampeana, constituyen ámbitos privilegiados para la exploración de las modalidades que asumen las articulaciones urbano-rurales, en tanto lugares alcanzados por el proceso de homogeneización productiva, mostrando cómo la emergencia de nuevos actores, lógicas y escalas de acción, interpela las aproximaciones tradicionales de análisis de los vínculos urbano-rurales y exige la necesidad de renovar enfoques, regulaciones e instrumentos solidarios con la gestión territorial sustentableProductive homogenization has altered the territorial construction processes inducing changes in the nature, intensity and directionality of urban-rural linkages in the pampean region. The creation of new joints and/or the redefinition of the pre-existing interactions involve functional, institutional and spatial dimensions, giving rise to specific forms of territorial resolution. Starting with approaches that upgrade the

  10. Unconscious Priming According to Multiple S-R Rules

    Science.gov (United States)

    Kiesel, Andrea; Kunde, Wilfried; Hoffmann, Joachim

    2007-01-01

    The present study investigated if unconscious primes can be processed according to different stimulus-response (S-R) rules simultaneously. Participants performed two different S-R rules, such as judging a digit as smaller or larger than five and judging a letter as vowel or consonant. These S-R rules were administered in random order and announced…

  11. Synthesis, crystal structure, and TEM analysis of Sr19Li44 and Sr3Li2: a reinvestigation of the Sr-Li phase diagram.

    Science.gov (United States)

    Smetana, Volodymyr; Kienle, Lorenz; Duppel, Viola; Simon, Arndt

    2015-02-02

    Two intermetallic phases in the Sr-Li system have been synthesized and structurally characterized. According to single-crystal X-ray diffraction data, Sr(19)Li(44) and Sr(3)Li(2) crystallize with tetragonal unit cells (Sr(19)Li(44), I-42d, a = 15.9122(7) Å, c = 31.831(2) Å, Z = 4, V = 8059(2) Å(3); Sr(3)Li(2), P42/mnm, a = 9.803(1) Å, c = 8.784(2) Å, Z = 4, V = 844.2(2) Å(3)). The first compound is isostructural with the recently discovered Ba(19)Li(44). Sr in Sr(19)Li(44) can be fully replaced by Ba with no changes to the crystal structure, whereas the substitution of Sr by Ca is only possible within a limited concentration range. Sr(3)Li(2) can be assigned to the Al(2)Zr(3) structure type. The crystal structure determination of Sr(19)Li(44) was complicated by multiple twinning. As an experimental highlight, an electron microscopy investigation of the highly moisture- and electron-beam-sensitive crystals was performed, enabling high-resolution imaging of the defect structure.

  12. Nuclear structure investigations of 84Sr and 86Sr using γ-ray spectroscopic methods

    Science.gov (United States)

    Duckwitz, H.; Petkov, P.; Thomas, T.; Ahn, T.; Blazhev, A.; Cooper, N.; Fransen, C.; Hinton, M.; Ilie, G.; Jolie, J.; Werner, V.

    2017-09-01

    To investigate the low-spin structure of 84Sr and 86Sr, two fusion-evaporation experiments using the (p,2n) reaction have been performed. The data have been evaluated in terms of γ-ray spectroscopy, i.e. the level scheme was built up, branching intensities were determined, nuclear state spin and parity assignments were made after γγ angular correlation analyses. The previously known level scheme information was extended. In addition, lifetimes were determined by means of the Doppler Shift Attenuation Method (DSAM). In 86Sr, a new method for lifetime determinations, the Spectral Difference Method (SDM), was applied for the first time. In cases where all necessary input variables were known, reduced transition strengths were calculated with Monte Carlo simulated probability density functions. It is stressed that linear error propagation for the calculated errors of reduced transition strengths is not universally applicable. As both nuclei lie in the vicinity of the N=50 neutron shell closure and on a possible proton subshell closure of the 2p3/2 orbital at Z=38, Nuclear Shell Model calculations for 84Sr, 86Sr, and 88Sr have been performed in the truncated (2p3/2, 1f5/2, 2p1/2, 1g9/2) model space for protons and neutrons with the empirical JUN45 residual interaction. The comparison between experimental results and theoretical predictions show a large degree of consistency.

  13. Exploring foraminiferal Sr/Ca as a new carbonate system proxy

    Science.gov (United States)

    Keul, Nina; Langer, Gerald; Thoms, Silke; de Nooijer, Lennart Jan; Reichart, Gert-Jan; Bijma, Jelle

    2017-04-01

    In present day paleoclimate research one of the most pressing challenges is the reconstruction of atmospheric CO2 concentrations. A variety of proxies for several components of the marine inorganic carbon system have been developed in this context (e.g. B isotopes, B/Ca, U/Ca) to allow reconstruction of past seawater pH, HCO3- and CO32- and thereby facilitate estimates of past atmospheric pCO2. Based on culture experiments using the benthic foraminifera Ammonia sp. we describe a positive correlation between Sr/Ca and the carbonate system, namely DIC/bicarbonate ion concentration. Foraminiferal Sr/Ca ratios provide potentially additional constraints on the carbonate system proxy, because the analysis of foraminiferal carbonate Sr/Ca is straightforward and not easily contaminated. Applying our calibration to a published dataset of paleo-Sr/Ca suggests the validity of Sr/Ca as a carbonate system proxy. Furthermore, we explore how our data can be used to advance conceptual understanding of the foraminiferal biomineralization mechanism.

  14. Optimizing of SPS pressed SrFe12O19 pellets from nano-powder

    DEFF Research Database (Denmark)

    Mortensen, Anna; Stingaciu, Marian; Christensen, Mogens

    2015-01-01

    Permanent magnets have great importance for many technological applications. Today researchers try making new and cheap magnets without rare earth elements. Strontium hexaferrite, SrFe12O19, is an important permanent magnet because of its large anisotropy, good performance/cost ratio, and high...

  15. SR1--a small RNA with two remarkably conserved functions.

    Science.gov (United States)

    Gimpel, Matthias; Preis, Heike; Barth, Emanuel; Gramzow, Lydia; Brantl, Sabine

    2012-12-01

    SR1 is a dual-function sRNA that acts as a base-pairing regulatory RNA on the ahrC mRNA and as a peptide-encoding mRNA on the gapA operon. The SR1-encoded peptide SR1P binds GapA thereby stabilizing gapA mRNA. Under glycolytic conditions, SR1 transcription is repressed by CcpN and CcpA. A computer-based search identified 23 SR1 homologues in Bacillus, Geobacillus, Anoxybacillus and Brevibacillus species. All homologues share a high structural identity with Bacillus subtilis SR1, and the encoded SR1P peptides are highly similar. In the Bacillus cereus group, the sr1p region is present in triplicate or duplicate resulting in longer SR1 species. In all cases, sr1 expression is under control of CcpN, and transcriptional lacZ fusions of nine examined SR1 homologues were sensitive to glucose. Two homologues showed an additional glucose-independent repression by CcpN and an unknown factor. A total of 10 out of 11 tested SR1P homologues complemented a B. subtilis Δsr1 strain in their ability to stabilize gapA mRNA, but only five of them bound GapA tightly. In vitro binding assays with six SR1/ahrC pairs suggest that-despite divergent primary sequences-the base-pairing function is also preserved. In summary, SR1 is an sRNA with two functions that have been conserved over ≈1 billion years.

  16. Transport of Sr 2+ and SrEDTA 2- in partially-saturated and heterogeneous sediments

    Science.gov (United States)

    Pace, M. N.; Mayes, M. A.; Jardine, P. M.; McKay, L. D.; Yin, X. L.; Mehlhorn, T. L.; Liu, Q.; Gürleyük, H.

    2007-05-01

    Strontium-90 has migrated deep into the unsaturated subsurface beneath leaking storage tanks in the Waste Management Areas (WMA) at the U.S. Department of Energy's (DOE) Hanford Reservation. Faster than expected transport of contaminants in the vadose zone is typically attributed to either physical hydrologic processes such as development of preferential flow pathways, or to geochemical processes such as the formation of stable, anionic complexes with organic chelates, e.g., ethylenediaminetetraacetic acid (EDTA). The goal of this paper is to determine whether hydrological processes in the Hanford sediments can influence the geochemistry of the system and hence control transport of Sr 2+ and SrEDTA 2-. The study used batch isotherms, saturated packed column experiments, and an unsaturated transport experiment in an undisturbed core. Isotherms and repacked column experiments suggested that the SrEDTA 2- complex was unstable in the presence of Hanford sediments, resulting in dissociation and transport of Sr 2+ as a divalent cation. A decrease in sorption with increasing solid:solution ratio for Sr 2+ and SrEDTA 2- suggested mineral dissolution resulted in competition for sorption sites and the formation of stable aqueous complexes. This was confirmed by detection of MgEDTA 2-, MnEDTA 2-, PbEDTA 2-, and unidentified Sr and Ca complexes. Displacement of Sr 2+ through a partially-saturated undisturbed core resulted in less retardation and more irreversible sorption than was observed in the saturated repacked columns, and model results suggested a significant reservoir (49%) of immobile water was present during transport through the heterogeneous layered sediments. The undisturbed core was subsequently disassembled along distinct bedding planes and subjected to sequential extractions. Strontium was unequally distributed between carbonates (49%), ion exchange sites (37%), and the oxide (14%) fraction. An inverse relationship between mass wetness and Sr suggested that

  17. Research

    African Journals Online (AJOL)

    The research was aimed at improving the current practice of radiation safety training of radiographers and was, therefore, considered action research.[18] The processes of action and research was integrated because the teaching activities and assessment were developed after the Delphi survey and aligned with the ...

  18. Research

    African Journals Online (AJOL)

    of the Western Cape (UWC), Cape Town, South Africa the students are exposed to research in various modules where they are trained in epidemiology, research methods and literature appraisal. In addition, they personally conduct a research project, performing relevant statistical analyses. The relevant modules for.

  19. Research

    African Journals Online (AJOL)

    ebutamanya

    2015-05-13

    May 13, 2015 ... Systems (SEEDS)-INDEPTH Network Accra, Ghana, 3KEMRI/Wellcome Trust Research Programme, The Centre of Geographical Medicine Research-. Coast, Kilifi, Kenya, 4Population Health Sciences/Research Support Unit, Faculty of Health Sciences, Aga Khan University- East Africa, Nairobi,. Kenya ...

  20. A method for determination of {sup 90}Sr in vegetation

    Energy Technology Data Exchange (ETDEWEB)

    Nygren, U

    1998-12-01

    This report describes a method for determination of {sup 90}Sr in vegetation. The method consists of wet-ashing the samples and separating Sr from the sample matrix by oxalate precipitation and extraction chromatography. {sup 90}Y ingrowth is awaited after which Y is separated from Sr and {sup 90}Y measured in a proportional counter. The method has been applied on two reference materials and the {sup 90}Sr results agree well with the recommended values. The method has also been used on 20 samples of blueberry twigs and the mean recovery of Sr was 74%

  1. Range expansion of Oligoryzomys longicaudatus (Rodentia, Sigmodontinae in Patagonian Chile, and first record of Hantavirus in the region Ampliación del rango de distribución de Oligoryzomys longicaudatus (Rodentia, Sigmodontinae en la Patagonia de Chile y primer registro de Hantavirus en la región

    Directory of Open Access Journals (Sweden)

    SEBASTIÁN BELMAR-LUCERO

    2009-06-01

    Full Text Available At present, 20 species of Oligoryzomys (Rodentia, Sigmodontinae are recognized in the Neotropical region, most of them distinguished by their karyotypes, which fluctuates between 46-70 chromosomes. Two species are currently recognized in Chile, Oligoryzomys longicaudatus (Bennet, 1832; "colilargo" or the long-tailed pygmy rice rat; 2n = 56, which ranges from 27° to approximately 51° S, and O. magellanicus (Bennet, 1836; Magellanic pygmy rice rat; 2n = 54, south of 51° S in the Patagonian region of Chile and Argentina. As part of an ongoing research on the southern Patagonia of Chile, we report the results of small mammal samplings in six localities. We karyotyped 28 specimens and we also sequenced the hypervariable mtDNA region I in 22 individuals, aligning these sequences with an under development phylogeny of O. longicaudatus. We also evaluated the serology and viral charge in all captured specimens to detect the presence of antibodies to Andes virus (ANDV through Strip Immunoblot Assay (SIA, and of viral genome by RT-PCR. The results consistently showed that the karyotype of southern Patagonia specimens was 2n = 56, equal to that of O. longicaudatus, and that individuals from this area do not differentiate phylogenetically from those of the northern range of distribution. In addition, the serology showed the presence of antibodies IgG anti-ANDV and of viral genome in heart, kidney, spleen, and lungs of a single specimen of Oligoryzomys from the locality of Fuerte Bulnes in the Magallanes region. We conclude that all specimens trapped south of 51° S correspond to Oligoryzomys longicaudatus, thus expanding the distribution of this specie! from 51° to at least 55° S. The results also extended the disiribution of the Andes strain of Hantavirus to southernmost Patagonia.Actualmente se reconocen 20 especies de Oligoryzomys (Rodentia, Sigmodontinae en la región Neotropical, la mayoría de ellas distinguidas por sus cariotipos, los que fluct

  2. Sr - an element shows the way - Applications of Sr isotopes for provenance, tracing and migration (Invited)

    Science.gov (United States)

    Prohaska, T.; Irrgeher, J.; Zitek, A.; Teschler Nicola, M.

    2010-12-01

    Strontium - named after the small Scottish town Strontian - as such is an element with little popularity. Firstly described by Martin Heinrich Klaproth in 1798, the metal is used in metallurgy to some extent whereas its compounds are interesting in glass industries, electronics and pyrotechnics. The element has chemical similarity to Ca and makes up 1/60 of the earth’s amount of the latter. Nonetheless, it is its isotopic composition which makes Sr so interesting for a large number of scientists. The natural composition of the four naturally occurring isotopes (84Sr, 86Sr 87Sr and 88Sr) varies in nature due to the radioactive decay of 87Rb to 87Sr. Thus, it was early recognized as geochronometer especially in Ca rich matrices. With increasing precision of applied methodology, the natural variation of the 87Sr/86Sr isotope ratio (analyzed at first mainly by thermal ionization mass spectrometry (TIMS)) became more and more popular in provenance studies. The natural variation of the ratio is mainly determined by the geological age and the original composition of the rock and can be used therefore as fingerprint of the local geology. The ratio is transferred with no significant fractionation via the water into plants and finally via the food chain into animal and human tissues (especially bones and teeth). As the element is chemically similar to Ca, it appears in most matrices. The use for provenance studies is supported by the fact that the long half life (4.8 x 1010 years) does not lead to an alteration during the time scales which are investigated (from recent samples to human or animal skeletal remains which date back up to 30.000 BC). The uniqueness of the system besides the natural variation is defined by the ubiquity in nature and the relatively high (and thus measurable) elemental concentration in most tissues. It was finally the advent of multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS) which augmented the number of applications

  3. Trends in (LaMnO3)n/(SrTiO3)m superlattices with varying layer thicknesses

    Science.gov (United States)

    Jiwuer, Jilili; Cossu, Fabrizio; Schwingenschlögl, Udo

    2015-03-01

    We investigate the thickness dependence of the structural, electronic, and magnetic properties of (LaMnO3)n/(SrTiO3)m (n, m = 2, 4, 6, 8) superlattices using density functional theory. The structure relaxation turns out to be highly sensitive to the onsite Coulomb interaction. In contrast to bulk SrTiO3, strongly distorted O octahedra are observed in the SrTiO3 layers with a systematic off centering of the Ti atoms. The systems favour ferromagnetic spin ordering rather than the antiferromagnetic spin ordering of bulk LaMnO3 and all show half-metallicity, while a systematic reduction of the minority spin band gaps as a function of the LaMnO3 and SrTiO3 layer thicknesses originates from modifications of the Ti dxy states. Research was supported by the King Abdullah University of Science and Technology (KAUST).

  4. SrRuO3 thin films grown on MgO substrates at different oxygen partial pressures

    KAUST Repository

    Zou, Bin

    2013-01-08

    A comprehensive study of SrRuO3 thin films growth on (001) MgO substrates by pulsed laser deposition in a wide oxygen pressure range from 10 to 300 mTorr was carried out. The experimental results showed a correlation between the lattice constants, resistivity, and oxygen partial pressures used. Ru deficiency detected only in films deposited at lower oxygen pressures (<50 mTorr), resulted in an elongation of the in-plane and out-of-plane lattice constants and an increase in the film resistivity. When deposited with oxygen partial pressure of 50 mTorr, SrRuO3 films had lattice parameters matching those of bulk SrRuO3 material and exhibited room temperature resistivity of 320 μΩ·cm. The resistivity of SrRuO 3/MgO films decreased with increasing oxygen partial pressure. Copyright © 2013 Materials Research Society.

  5. Strontium (Sr) separation from seawater using titanate adsorbents: Effects of seawater matrix ions on Sr sorption behavior

    Science.gov (United States)

    Ryu, Jungho; Hong, Hye-jin; Ryu, Taegong; Park, In-Su

    2017-04-01

    Strontium (Sr) which has many industrial applications such as ferrite magnet, ceramic, and fire works exists in seawater with the concentration of approximately 7 mg/L. In previous report estimating economic potential on recovery of various elements from seawater in terms of their commercial values and concentrations in seawater, Sr locates upper than approximate break-even line, which implies Sr recovery from seawater can be potentially profitable. Recently, Sr separation from seawater has received great attention in the environmental aspect after Fukushima Nuclear Power Plant (NPP) accident which released much amount of radioactive Sr and Cs. Accordingly, the efficient separation of radioactive elements released to seawater has become critical as an important technological need as well as their removal from radioactive wastes. So far, it has been introduced to separate Sr from aqueous media by various methods including solvent extraction, adsorption by solid materials, and ion exchange. Among them, the adsorption technique using solid adsorbents is of great interest for selectively separating Sr from seawater with respect to low concentration level of Sr. In this study, we synthesized titanate nanotube (TiNT) by simple hydrothermal reaction, characterized its physicochemical properties, and systematically evaluated Sr sorption behavior under various reaction conditions corresponding to seawater environment. The synthesized TiNT exhibited the fibril-type nanotube structure with high specific surface area of 260 m2/g. The adsorption of Sr on TiNT rapidly occurred following pseudo-second-order kinetic model, and was in good agreement with Langmuir isotherm model, indicating maximum adsorption capacity of 97 mg/g. Based on Sr uptake and Na release with stoichiometric balance, sorption mechanism of Sr on TiNT was found to be ion-exchange between Na in TiNT lattice and Sr in solution phase, which was also confirmed by XRD and Raman analysis. Among competitive ions, Ca

  6. 87Sr/86Sr Concentrations in the Appalachian Basin: A Review

    Energy Technology Data Exchange (ETDEWEB)

    Mordensky, Stanley P. [Oak Ridge Inst. for Science and Education (ORISE), Oak Ridge, TN (United States); National Energy Technology Lab. (NETL), Albany, OR (United States); Lieuallen, A. Erin [Oak Ridge Inst. for Science and Education (ORISE), Oak Ridge, TN (United States); National Energy Technology Lab. (NETL), Albany, OR (United States); Verba, Circe [National Energy Technology Lab. (NETL), Albany, OR (United States); Hakala, Alexandra [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)

    2016-06-16

    This document reviews 87Sr/86Sr isotope data across the Appalachian Basin from existing literature to show spatial and temporal variation. Isotope geochemistry presents a means of understanding the geochemical effects hydraulic fracturing may have on shallow ground substrates. Isotope fractionation is a naturally occurring phenomenon brought about by physical, chemical, and biological processes that partition isotopes between substances; therefore, stable isotope geochemistry allows geoscientists to understand several processes that shape the natural world. Strontium isotopes can be used as a tool to answer an array of geological and environmental inquiries. In some cases, strontium isotopes are sensitive to the introduction of a non-native fluid into a system. This ability allows strontium isotopes to serve as tracers in certain systems. Recently, it has been demonstrated that strontium isotopes can serve as a monitoring tool for groundwater and surface water systems that may be affected by hydraulic fracturing fluids (Chapman et al., 2013; Kolesar Kohl et al., 2014). These studies demonstrated that 87Sr/86Sr values have the potential to monitor subsurface fluid migration in regions where extraction of Marcellus Shale gas is occurring. This document reviews publicly available strontium isotope data from 39 sample locations in the Appalachian Basin (Hamel et al., 2010; Chapman et al., 2012; Osborn et al., 2012; Chapman et al., 2013; Capo et al., 2014; Kolesar Kohl et al., 2014). The data is divided into two sets: stratigraphic (Upper Devonian/Lower Mississippi, Middle Devonian, and Silurian) and groundwater. ArcMap™ (ESRI, Inc.) was used to complete inverse distance weighting (IDW) analyses for each dataset to create interpolated surfaces in an attempt to find regional trends or variations in strontium isotopic values across the Appalachian Basin. 87Sr/86Sr varies up to ~ 0.011 across the

  7. Localization of CaSR antagonists in CaSR-expressing medullary thyroid cancer.

    Science.gov (United States)

    Ding, Haiming; Yusof, Adlina Mohd; Kothandaraman, Shankaran; Saji, Motoyasu; Wang, Chaojie; Kumar, Krishan; Milum, Keisha; Carleton, Michelle; Pan, Xueliang; Ringel, Matthew D; Tweedle, Michael F; Phay, John E

    2013-11-01

    Image-based localization of medullary thyroid cancer (MTC) and parathyroid glands would improve the surgical outcomes of these diseases. MTC and parathyroid glands express high levels of calcium-sensing receptor (CaSR). The aim of this study was to prove the concept that CaSR antagonists specifically localize to CaSR-expressing tumors in vivo. We synthesized two isomers of a known CaSR calcilytic, Calhex 231, and four new analogs, which have a favorable structure for labeling. Their antagonistic activity was determined using immunoblots demonstrating decreased ERK1/2 phosphorylation after calcium stimulation in human embryonic kidney cells overexpressing CaSR. Compound 9 was further radiolabeled with (125)I and evaluated in nude mice with and without heterotransplanted xenografts of MTC cell lines, TT and MZ-CRC-1, that do and do not express CaSR, respectively. Two newly synthesized compounds, 9 and 11, exhibited better antagonistic activity than Calhex 231. The half-life of (125)I-compound 9 in nude mice without xenografts was 9.9 hours. A biodistribution study in nude mice bearing both tumors demonstrated that the uptake of radioactivity in TT tumors was higher than in MZ-CRC-1 tumors at 24 hours: 0.39 ± 0.24 vs 0.18 ± 0.12 percentage of injected dose per gram of tissue (%ID/g) (P = .002), with a ratio of 2.25 ± 0.62. Tumor-to-background ratios for TT tumors, but not MZ-CRC-1 tumors, increased with time. Tumor-to-blood values increased from 2.02 ± 0.52 at 1 hour to 3.29 ± 0.98 at 24 hour (P = .015) for TT tumors, and 1.7 ± 0.56 at 1 hour to 1.48 ± 0.33 at 24 hour (P = .36) for MZ-CRC-1 tumors. Our new CaSR antagonists specifically inhibit CaSR function in vitro, preferentially localize to CaSR-expressing tumors in vivo, and therefore have the potential to serve as scaffolds for further development as imaging pharmaceuticals.

  8. Some aspects of SR beamline alignment

    Energy Technology Data Exchange (ETDEWEB)

    Gaponov, Yu.A., E-mail: Yury.Gaponov@maxlab.lu.se [MAX-lab, Lund University, P.O.B. 118, SE-221 00 Lund (Sweden); Cerenius, Y. [MAX-lab, Lund University, P.O.B. 118, SE-221 00 Lund (Sweden); Nygaard, J. [Faculty of Life Sciences, University of Copenhagen, DK-1871 Frederiksberg C (Denmark); Ursby, T.; Larsson, K. [MAX-lab, Lund University, P.O.B. 118, SE-221 00 Lund (Sweden)

    2011-09-01

    Based on the Synchrotron Radiation (SR) beamline optical element-by-element alignment with analysis of the alignment results an optimized beamline alignment algorithm has been designed and developed. The alignment procedures have been designed and developed for the MAX-lab I911-4 fixed energy beamline. It has been shown that the intermediate information received during the monochromator alignment stage can be used for the correction of both monochromator and mirror without the next stages of alignment of mirror, slits, sample holder, etc. Such an optimization of the beamline alignment procedures decreases the time necessary for the alignment and becomes useful and helpful in the case of any instability of the beamline optical elements, storage ring electron orbit or the wiggler insertion device, which could result in the instability of angular and positional parameters of the SR beam. A general purpose software package for manual, semi-automatic and automatic SR beamline alignment has been designed and developed using the developed algorithm. The TANGO control system is used as the middle-ware between the stand-alone beamline control applications BLTools, BPMonitor and the beamline equipment.

  9. Implicazioni cliniche ed economiche di tramadolo SR

    Directory of Open Access Journals (Sweden)

    Lorenzo Pradelli

    2004-12-01

    Full Text Available Tramadol is one of the preferred weak opioid agonists in the management of chronic pain, due to a good efficacy and safety profile, to a particularly low interference with cardiovascular and respiratory functions and a low dependence and abuse potential. The successful use of tramadol, nevertheless, is often limited by low patient compliance, a consequence of gastrointestinal side effects (mainly nausea and vomiting and frequent dosing regimens, among other reasons. In this paper, clinical studies conducted on slow-release formulations of tramadol and other strategies for compliance improvement in various pain conditions are reviewed. From the examined literature, it appears that the strategy with the best compliance is the use of slow release (SR formulations, which simplify dosing regimens and tend to have a somewhat better tolerability, and a slow dose escalation, which improves tolerability. The advantages of SR formulations have to be weighed against the superior acquisition cost and the slower onset of analgesia. A frame for the evaluation of the clinical and economical advantages and disadvantages of SR versus immediate release formulations of tramadol is also proposed.

  10. Research.

    Science.gov (United States)

    Raudenbush, Stephen

    In May of 1999, the American Academy of Arts and Sciences hosted a conference on ways to improve the scientific quality of educational research. In medicine, thanks to work 40 years ago by 2 researchers, Howard Hyatt and Frederick Mosteller, the commitment of medical professionals to base their diagnoses and prescriptions on clinical trials in…

  11. Research

    African Journals Online (AJOL)

    Results. Three emergent themes were identified from the results of this study: a lack of standardised guidelines for nurse academics to effectively supervise postgraduate research; the pressure that nurse academics experience regarding postgraduate research supervision; other demanding roles of an academic, such as a ...

  12. Research

    African Journals Online (AJOL)

    first time, on the findings of a research study on the implementation of field trips in a management module in the BPharm curriculum and to conclude whether this intervention changed pharmacy students' perception of the module. Method. A mixed-method sequential exploratory research design was followed,.

  13. Research

    African Journals Online (AJOL)

    abp

    2016-04-29

    Apr 29, 2016 ... Anonymity of respondents was assured by concealing their identity and research data was kept confidential for research purposes only. The study was conducted by full adherence of the ..... Samwel K. Misoi, Richard K. Rotich, Anthony K. Mwanthi and George. M. Mwita for their moderation throughout the ...

  14. Research

    African Journals Online (AJOL)

    An interview guide approach was implemented in face-to-face in-depth interviews ... Dependability of the data collected was ensured through an audit trail. The main researcher and supervisor served as peer .... [16] A growing body of research reports that students with high academic resilience and self-efficacy are more ...

  15. Research

    African Journals Online (AJOL)

    Research. 108 September 2017, Vol. 9, No. 3 AJHPE. Methods. This is a qualitative descriptive study that explored nursing students' experiences. ..... Challenges and lessons learned. Clin. Simulation Nursing 2013;9(5):e157-e162. https://doi.org/10.1016/j.ecns.2011.11.011. 12. Creswell JW. Research Design. 4th ed.

  16. 75 FR 23671 - Endangered and Threatened Species; Take of Anadromous Fish; Research Permit Applications

    Science.gov (United States)

    2010-05-04

    ...), threatened Snake River (SR) spring/summer (spr/sum), threatened SR fall, threatened Puget Sound (PS). Chum... Pacific lamprey in the Snake River basin. The research is designed to assess lamprey numbers and habitat...

  17. Development of Eu:SrI2 Scintillator Array for Gamma-Ray Imaging Applications

    Science.gov (United States)

    Yoshino, Masao; Kamada, Kei; Shoji, Yasuhiro; Kurosawa, Shunsuke; Yokota, Yuui; Ohashi, Yuji; Yoshikawa, Akira; Yamamoto, Seiichi

    2017-07-01

    Eu:SrI2 bulk single crystals with 1.5-in diameter were grown using the Bridgman-Stockbarger technique and special-shaped crucibles. We will report on the growth of the 1.5-in size Eu:SrI2 single crystal and the preliminary test of the same sample cut in size of 10×10×10 mm3 with polishing. An energy resolution of 3.2% full width at half maximum (FWHM) was obtained for 137Cs. After cutting and polishing the grown crystal to the size of 3×3×3 mm3, 8×8 matrix Eu:SrI2 arrays were fabricated. We made a test module consisting of Eu:SrI2 arrays, which was optically coupled with position sensitive photomultiplier tube (PSPMT) and multi-pixel photon counter (MPPC) array. The position and energy performance of the test module were evaluated using 137Cs and 57Co radioactive sources. As a result, we were able to resolve all pixels clearly. A good energy resolution of 6.7% ± 0.7% (FWHM) and 8.2% ± 2.5% (FWHM) for 662 keV was obtained using PSPMT and MPPC arrays, respectively. In the same way, energy resolution of 12.7% ± 1.3% and 14.7% ± 3.4% (FWHM) for 122 keV was obtained using PSPMT and MPPC-array, respectively. These energy resolutions considerably degraded compared with an energy resolution of the single piece of Eu:SrI2 sample owing to the thinness of the Teflon reflector. This conclusion can be considered as a strong motivation for future research on the choice of reflector materials and structure of the Eu:SrI2 array.

  18. Research

    African Journals Online (AJOL)

    abp

    2015-09-09

    Sep 9, 2015 ... Traumatology, Umraniye Research and Education Hospital, 34899 ... This is an Open Access article distributed under the terms of the Creative Commons .... and major complication such as pain, seroma, dog ears, widening of.

  19. Research

    African Journals Online (AJOL)

    that should promote basic capabilities and functionings as well as academic achievement. ... for development and wellbeing on an educational, personal and social level.[2] ... Research indicates that academic stressors, living circumstances, working conditions and where students undertake leisure activities affect.

  20. Research

    African Journals Online (AJOL)

    ebutamanya

    2015-08-28

    Aug 28, 2015 ... Ethiopia, 2Bahir Dar Regional Health Research Laboratory Center, Department ... of Public Health, 4Institute of Medical Microbiology and Epidemiology of Infectious .... active ingredient x 10,000 dilution rate of product): 0.1%.

  1. Research

    African Journals Online (AJOL)

    raoul

    2011-11-14

    Nov 14, 2011 ... Background: For many women in Kenya, their husbands act as ... and researching whether men are translating this knowledge into action ..... older participants, and participants with multiparous wives, reflecting personal.

  2. Magmatic versus sedimentary 87Sr/86Sr signature in groundwater circulating in a basaltic volcanic systems: Mt. Etna

    Science.gov (United States)

    Liotta, Marcello; D'Alessandro, Walter; Arienzo, Ilenia; Longo, Manfredi

    2017-04-01

    Volcanoes can host large aquifers and thereby represent important water resources. Groundwater interacting with volcanics dissolves volcanogenic elements that subsequently flow through the aquifers. Volcanic systems often overlie a crustal basement. At Mt. Etna, groundwater mainly circulates in the permeable volcanics that overlie impermeable terrains composed by allochthonous series of flysch and postorogenic clayey sediments. The use of Sr isotopes is a well-established approach for tracing fluids in the crust. Since the 87Sr/86Sr ratio of the volcanics at Mt. Etna exhibits a range that differs significantly from that of the sedimentary basement, the Sr-isotope composition provides a useful tool for evaluating the interaction between shallow groundwater circulating in the volcanics and deep brines circulating in the sedimentary basement. Nowadays it is well known that the main aquifer on Mt. Etna is hosted in the volcanics. Samples from 14 sites were collected and analyzed for their chemical composition and Sr-isotope ratios. While the most common approach of coupling 87Sr/86Sr ratios with the concentration of dissolved Sr is not effective in distinguishing between the deep brine and possible seawater contributions, we suggest that the Sr/Cl ratio is a useful complementary parameter that needs to be considered when attempting to clearly identify the Sr sources. The obtained data indicate that the Sr-isotope signature of groundwater is determined by the volcanics of the aquifer. The volcanic isotopic signature is modified by very small amounts of brines (circulates almost in contact with the sedimentary basement. The proposed approach is potentially very effective for tracing the circulation of groundwater not only at Mt. Etna but also at volcanic edifices that overlie a bedrock with different 87Sr/86Sr ratios as well as at volcanic islands where freshwater overlies seawater.

  3. The cellular cancer resistance of the SR/CR mouse

    DEFF Research Database (Denmark)

    Koch, Janne; Hau, Jann; Jensen, Henrik Elvang

    2012-01-01

    , macrophages and natural killer cells. A relative decrease in influx of B-cells compared with controls was demonstrated. Increased proportions of leukocytes belonging to the innate immune system were also demonstrated in splenocytes of SR/CR mice. Cytospins of peritoneal fluid from SR/CR mice after cancer cell......, macrophages and NK cells into the peritoneum of the SR/CR mouse in response to intraperitoneal injection of S180 cancer cells. The cell composition of spleens of SR/CR mice reflected the differential regulation of the innate immune cells in peritoneal exudates. Both peritoneal exudates and the spleens of SR......-activated cell sorting analysis, the immune response of SR/CR mice after intraperitoneal injection of cancer cells was investigated and compared with parent strain mice. A massive influx of leukocytes into the peritoneal cavity was found. A large fraction of these leukocytes were polymorphonuclear granulocytes...

  4. SR-71A on Ramp with Dual Max Afterburner Engines Firing

    Science.gov (United States)

    1998-01-01

    This night shot shows one of NASA's SR-71 Blackbird research aircraft on the ramp at the Dryden Flight Research Center, Edwards, California, with both engines running in max afterburner. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the airstream. One of Dryden's SR-71s was used for the Linear Aerospike Rocket Engine, or LASRE Experiment. Another earlier project consisted of a series of flights using the SR-71 as a science camera platform for NASA's Jet Propulsion Laboratory in Pasadena, California. An upward

  5. Research

    African Journals Online (AJOL)

    abp

    2013-11-06

    Nov 6, 2013 ... 1University of Botswana, Gaborone, Botswana, 2Research Institute for Humanity and Nature, Kyoto, Japan, 3School of Public Health, University of the Western Cape, Bellville, South Africa, 4Japan Overseas Christian Medical Co-operative Services, C/o Roman Catholic Archdiocese of Tabora,. Private Bag ...

  6. Research

    African Journals Online (AJOL)

    212-218. [http:// dx.doi.org/10.1207/s15430421tip4104_2]. 22. Pepper C. 'There's a lot of learning going on but NOT much teaching!': Student perceptions of problem-based learning in science. Higher Education Research & Development 2010 ...

  7. Research

    African Journals Online (AJOL)

    2017-03-24

    Mar 24, 2017 ... 26 March 2017, Vol. 9, No. 1 AJHPE. Research were distributed among varying levels of advancement within the EM training programme (Table 1). Responses to the qualitative section of the survey were categorised into major themes, providing insight into the overall acceptability of small-group education.

  8. Research

    African Journals Online (AJOL)

    Research. December 2017, Vol. 9, No. 4 AJHPE 189. Community-based education (CBE) is a learning approach that enables students to acquire skills by means of ... of CBE include early contact with the community, improved teamwork of ... A descriptive cross-sectional survey was conducted at the University of Zimbabwe.

  9. Research

    African Journals Online (AJOL)

    ebutamanya

    2015-08-06

    Aug 6, 2015 ... permanent contraceptive methods and women's education (AOR=1.72, 95%CI = 1.02 - 3.05), women's occupation (AOR = 2.01, 95% CI = 1.11 -. 3.58), number of live .... NGO's and presence of different Medias in the area. The result of this .... Social and Behavior Change Communication. Research Brief.

  10. Research

    African Journals Online (AJOL)

    abp

    2016-01-27

    Jan 27, 2016 ... (SD) age of the male subjects was 38.4(14.9) years and that of the females was 40.8(13.9) years (p> 0.05). The overall ... Published in partnership with the African Field Epidemiology Network (AFENET). (www.afenet.net) ... Trained research assistants administered questionnaires and obtained the ...

  11. Research

    African Journals Online (AJOL)

    YouTube, TED and other podcast websites. Other researchers have also documented their procedures. Corl et al.[5] describe the basic process of producing a podcast, and Jham et al.[6] list a number of universities actively doing podcasts. Besides the lecture podcasts, we have also captured numerous clinical.

  12. Research

    African Journals Online (AJOL)

    abp

    2015-01-05

    Jan 5, 2015 ... Methods: this was a descriptive cross-sectional study conducted in Talensi district in the Upper East Region of Ghana. Systematic random ..... 14. Saunders MNK, Lewis P and Thornhill A. Research methods for business students. FT Prentice Hall. (2003); 3rd Edition. Harlow. Google Scholar. 15. Allen K ...

  13. Research

    African Journals Online (AJOL)

    raoul

    2012-02-17

    Feb 17, 2012 ... Organizational Behaviour and Human Decision Processes. 2000; 50: 79-211. 13. Montano DE and Kasprzyk D. The Theory of Reasoned Action and the Theory of Planned Behaviour Glanz, K Lewis, FM Rimer, BK eds. Health Behaviour and Health Education, Theory, Research and Practice: Jossy Bass ...

  14. Research

    African Journals Online (AJOL)

    abp

    2016-04-15

    Apr 15, 2016 ... 1National Reference Center in Neonatology and Nutrition, Children's Hospital, University Hospital, Rabat, Morocco, 2Research Team on Health and ... This is an Open Access article distributed under the terms of the Creative Commons .... were globally performed in older mothers with a mean age of 31.5.

  15. Research

    African Journals Online (AJOL)

    the standard of future practice. Therefore, it is imperative for healthcare educators to understand the issues students face in their everyday fieldwork practice and equip them to deal with these ethical issues. Objectives. The objective of this research was to determine the issues that students face in their fieldwork practice and ...

  16. Research

    African Journals Online (AJOL)

    ebutamanya

    2015-01-15

    Jan 15, 2015 ... diagnosed cases with FNAB as either benign or malignant when correlated with histology were 95% and 100% respectively. Conclusion: FNAB is ... foot). This study was conducted in compliance with the guidelines of the Helsinki declaration on biomedical research in human subjects. Confidentiality of the ...

  17. Research

    African Journals Online (AJOL)

    ebutamanya

    2015-12-16

    Dec 16, 2015 ... of this policy, there is need to monitor the implementation progress, identify the challenges and mitigate them and determine better strategies for implementation .... Ethical Considerations: ethical Clearance to carry out the research ... 10% of the respondents reported that the government was doing enough ...

  18. Research

    African Journals Online (AJOL)

    ebutamanya

    Received: 03/12/2014 - Accepted: 15/01/2015 - Published: 13/03/2015. Abstract. Introduction: ... Studies have called on the need for further additional research to establish how supportive supervision in health systems should be best carried out effectively .... male to female medical practitioners in Kenya stood at 60% and.

  19. Research

    African Journals Online (AJOL)

    abp

    2015-06-09

    Jun 9, 2015 ... The authors sincerely thank the staff of Clinical Research Education,. Networking and Consultancy (CRENC), Douala Cameroon for statistical analysis, data interpretation and assistance in drafting the manuscript. Tables and figures. Table 1: Characteristics (socio-demographic and clinical) of women.

  20. Research

    African Journals Online (AJOL)

    abp

    2013-10-29

    Oct 29, 2013 ... mosquito-borne diseases, however, limited research has been documented on infections with dengue. This study ... presence of antibodies against dengue virus 2 (denv-2) in a cross-section of febrile out-patients visiting three selected hospitals to assess the level .... treatments prescribed was recorded.

  1. Research

    African Journals Online (AJOL)

    abp

    2017-05-10

    May 10, 2017 ... (Approval number B/874), Joint Research Ethics Committee, Health Studies Office and the Manicaland Directorate Institutional Review Board. Written informed .... parasites, but without any features of severe malaria between. September ..... T-lymphocytes, impairment of antibody formulation and atrophy of.

  2. Research

    African Journals Online (AJOL)

    abp

    2016-04-14

    Apr 14, 2016 ... Methods: A mixed methods study was conducted using both .... Methods. Study design: A mixed method cross-sectional design using both quantitative and qualitative research methods as described by. Hanson et al [33] was employed. ..... Musheke M, Ntalasha H, Gari S, McKenzie O, Bond V, Martin-.

  3. Research

    African Journals Online (AJOL)

    raoul

    2011-08-25

    Aug 25, 2011 ... euthanasia were also queried. Data was analyzed using Epidata, SPSS 16.0 and Microsoft Excel. Results: Thirty-eight (97.4%) of thirty-nine institutions reported using animals for education and/or research. Thirty (76.9%) institutions reported using analgesics or anesthetics on a regular basis. Thirteen ...

  4. Research

    African Journals Online (AJOL)

    abp

    2016-04-28

    Apr 28, 2016 ... Published in partnership with the African Field Epidemiology Network (AFENET). (www.afenet.net). Research .... interstitial compartment and may lead to distal tubular damage, some with attendant nephrogenic diabetes ..... Model Summary R=0.861, R2=0.742, Standard error of estimate=0.046, p<0.001.

  5. Research

    African Journals Online (AJOL)

    ebutamanya

    2015-01-30

    Jan 30, 2015 ... Published in partnership with the African Field Epidemiology Network (AFENET). (www.afenet.net). Research. Open Access ... compartment syndrome [4,5]. According to the literature, incidence ... fed into a multiple regression model to assess the odds ratio. Results. Between March 2012 and March 31, ...

  6. Research

    African Journals Online (AJOL)

    1 AJHPE 43. Research. Patient-centredness requires pharmacists to view their patients as individuals with unique experiences.[1] Each patient in their social context responds uniquely to ... To determine the prevalence of the 16 different Myers-Briggs Type Indicator®(MBTI®) communication styles, and compare them with.

  7. Research

    African Journals Online (AJOL)

    The mixed-methods approach was selected as the most appropriate research design for data collection and analysis. The use of multiple data collection instruments and sources provided a broader perspective and deeper understanding of the core concepts of the evaluation from the perspective of multiple sources. Results ...

  8. Research

    African Journals Online (AJOL)

    During Phase I of the mixed-methods research design, data were collected by means of a nominal group technique. Nominal group discussions were held with the class leaders to identify possible themes/ topics to describe the perceptions of health sciences students with regard to. CBE and SL. These themes and topics ...

  9. Research

    African Journals Online (AJOL)

    than student assessment.[12,13] One needs to ... Cut scores for students' assessments have always been arbitrarily determined in many institutions. Some institutions ..... Research. December 2017, Vol. 9, No. 4 AJHPE 175 correct answers to the judges before the scoring exercise, an observation that arguably creates bias.

  10. Research

    African Journals Online (AJOL)

    2 AJHPE. Research. The Ugandan Ministry of Health (MOH) identified lack of leadership and management skills, rather than lack of resources, as the main reason for poor healthcare delivery in the country.[1] Healthcare professionals, as an integral component of Uganda's healthcare system, receive a high level of training ...

  11. Research

    African Journals Online (AJOL)

    raoul

    2012-01-11

    Jan 11, 2012 ... 1MPH Programme, Department of Community Medicine, University of Zimbabwe, Zimbabwe, 2Department of Epidemiology and Disease Control,. Ministry ... Pan African Medical Journal. 2012; 11: ..... Mufuta Tshimanga: Had oversight of all the stages of the research and critically reviewed the final draft for.

  12. Research

    African Journals Online (AJOL)

    Research. Clinical teaching is a technique used in the education of nurses. It involves the exposure of students to authentic clinical environments and guiding them to attain specific requirements applicable in that particular environment.[1] The clinical environment is a platform for the application of knowledge and skills that ...

  13. Research

    African Journals Online (AJOL)

    This model involves the allocation of nursing students to a qualified professional nurse who, in the course of ... who qualified in general nursing and midwifery at a rural hospital in. Lesotho. Eight professional .... research that explored the experiences and perceptions of healthcare workers in clinical environments about the ...

  14. Research

    African Journals Online (AJOL)

    ebutamanya

    2016-04-20

    Apr 20, 2016 ... were reviewed using an agreed data collection pro forma considering 3 main outcomes; i) quantity of complete entries, ii) percentage completeness of individual sections, iii) documentation ... impossible to evaluate the reliability of this data and the utility of these books as a tool for research. A clinical audit ...

  15. Research

    African Journals Online (AJOL)

    abp

    2017-05-01

    May 1, 2017 ... p=0.019) respectively. Conclusion: Patient's perceived attitude and stigma towards treatment observers contribute to non-adherence on TB treatment. For improved local TB control, ... Published in partnership with the African Field Epidemiology Network (AFENET). (www.afenet.net). Research. Open Access ...

  16. Research

    African Journals Online (AJOL)

    tions as their reality.[14]. Research context. At Stellenbosch University (SU), Cape Town,. SA, final-year physiotherapy students each spend. 6 weeks at a community site learning to integrate and apply the principles of PHC and community- based rehabilitation. Approximately 5 - 10 clients are seen in their homes per week.

  17. Research

    African Journals Online (AJOL)

    acquire public health, clinical, and/or research skills, usually through applied learning in a community setting,[1] with goals that include: creating knowledge, skills and attitudes among students to ensure they are capable of providing high- quality health services to local, underserved communities, often in rural areas.

  18. Research

    African Journals Online (AJOL)

    Communities provide the reality of social and health challenges and therefore provide the platform for learning and exploring their authentic challenges.[1] Community-university partnerships are thus intended to bring together academic researchers and communities, share power, establish trust, foster co-learning, enhance ...

  19. Research

    African Journals Online (AJOL)

    good) and the weaknesses (things that need to be improved) of students' performance, and possible things that can be improved after the mini-CEX assessment. The existence of this reflection on experience indicates that there has been a deep learning process.[12,14] We suggest that future research should elaborate on ...

  20. Research

    African Journals Online (AJOL)

    abp

    2016-07-13

    Jul 13, 2016 ... definitions of invasive fungal disease of the European Organization for Research and Treatment of Cancer/Mycosis Study Group. (EORTC/MSG) [15]. In total, 91 patients were identified that among them, 16 were excluded because of discharge against medical advice. The cases that were diagnosed on an ...

  1. Research

    African Journals Online (AJOL)

    abp

    2016-05-13

    May 13, 2016 ... based study that enrolled breast cancer patients from catchment area of an oncology service hospital in Nigeria between 2007 and 2013. ... ISSN: 1937- 8688 (www.panafrican-med-journal.com). Published in partnership with the African Field Epidemiology Network (AFENET). (www.afenet.net). Research.

  2. Research

    African Journals Online (AJOL)

    raoul

    2012-02-17

    Feb 17, 2012 ... Psychology and Health. 2001; 16(4): 423-441. 15. Creswell J: Research Design. Qualitative & Quantitative Approaches. 1994; Sage Publications. 16. Biomedical communication. Avalable at http://www.bmc.med.utoronto.ca/bmc/index.php. Accessed 1 February 2012. 17. Glaser BG. Emergence vs. Forcing.

  3. Research

    African Journals Online (AJOL)

    2017-03-02

    Mar 2, 2017 ... In summary, this study explored the perceptions and experiences of nurse educators' use of HFS in teaching, as its acceptability by educators as a teaching strategy is important for effective use. Methods. Research design. A descriptive, qualitative case study design was utilised to explore nursing.

  4. Research

    African Journals Online (AJOL)

    2014-05-02

    May 2, 2014 ... the quality of graduates and providing them with the necessary skills and competencies to ... However, most of the aforementioned evaluation studies focus on the training process .... except two areas, i.e. X-ray image interpretation and research skills. All 72 respondents ... Ultrasound. Mammography.

  5. Research

    African Journals Online (AJOL)

    2016-05-26

    May 26, 2016 ... [5] At the nucleus of systems thinking is the ability 'to balance the interests of several conflicting interests with an ultimate focus on the benefit of the institution as a whole'. ... The longitudinal series of interviews formed part of the first author's action research design,[8] aimed at her professional development.

  6. Research

    African Journals Online (AJOL)

    abp

    2014-03-13

    Mar 13, 2014 ... Published in partnership with the African Field Epidemiology Network (AFENET). (www.afenet.net). Research ..... Artisan. 361(15.1). Civil servant. 348(14.6). Professional/Business Executive. 138(5.8). Mode of acquisition of HIV. Heterosexual Contact. 1876(78.5). Blood and Blood product. 129(5.4). MTCT.

  7. SR-71A - in Flight View from Tanker during an Airborne Refueling

    Science.gov (United States)

    1997-01-01

    This photo shows a USAF tanker aircraft Boom Operator's or 'Boomer's' view of NASA Dryden Flight Research Center's SR-71A, tail number 844, following air refueling during a 1997 flight. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the airstream. One of Dryden's SR-71s was used for the Linear Aerospike Rocket Engine, or LASRE Experiment. Another earlier project consisted of a series of flights using the SR-71 as a science camera platform for NASA's Jet Propulsion Laboratory in Pasadena, California. An upward

  8. SR-71B - in Flight with F-18 Chase Aircraft - View from Air Force Tanker

    Science.gov (United States)

    1996-01-01

    NASA 831, an SR-71B operated by the Dryden Flight Research Center, Edwards, California, cruises over the Mojave Desert with an F/A-18 Hornet flying safety chase. They were photographed on a 1996 mission from an Air Force refueling tanker The F/A-18 Hornet is used primarily as a safety chase and support aircraft at Dryden. As support aircraft, the F-18s are used for safety chase, pilot proficiency and aerial photography. Two SR-71 aircraft have been used by NASA as testbeds for high-speed and high-altitude aeronautical research. The aircraft, an SR-71A and an SR-71B pilot trainer aircraft, have been based here at NASA's Dryden Flight Research Center, Edwards, California. They were transferred to NASA after the U.S. Air Force program was cancelled. As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees Fahrenheit (F). This operating environment makes these aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. The SR-71 was used in a program to study ways of reducing sonic booms or over pressures that are heard on the ground, much like sharp thunderclaps, when an aircraft exceeds the speed of sound. Data from this Sonic Boom Mitigation Study could eventually lead to aircraft designs that would reduce the 'peak' overpressures of sonic booms and minimize the startling affect they produce on the ground. One of the first major experiments to be flown in the NASA SR-71 program was a laser air data collection system. It used laser light instead of air pressure to produce airspeed and attitude reference data, such as angle of attack and sideslip, which are normally obtained with small tubes and vanes extending into the airstream. One of Dryden's SR-71s was used

  9. Microstructural characterization of Mg–Al–Sr alloys

    Directory of Open Access Journals (Sweden)

    M. Aljarrah et al

    2007-01-01

    Full Text Available The microstructural details of fourteen Mg–Al–Sr alloys were investigated in the as-cast form by a combination of scanning electron microscopy/energy dispersive spectrometer (SEM/EDS analysis and quantitative electron probe microanalysis (EPMA. The heat transfer method coupled with the DSC measurement has been utilized to determine the solidification curves of the alloys. The morphology and the chemical composition of the phases were characterized. The microstructure of the alloys is primarily dominated by (Mg and (Al4Sr. In the present investigation, ternary solid solubility of three binary compounds extended into the ternary system has been reported and denoted as: (Al4Sr, (Mg17Sr2 and (Mg38Sr9. The (Al4Sr phase is a substitutional solid solution represented by MgxAl4−xSr and has a plate-like structure. The maximum solubility of Al in Mg17Sr2 was found to be 21.3 at%. It was also observed that Mg38Sr9 dissolved 12.5 at% Al.

  10. Carrier-Controlled Ferromagnetism in SrTiO_{3}

    Directory of Open Access Journals (Sweden)

    Pouya Moetakef

    2012-06-01

    Full Text Available Magnetotransport and superconducting properties are investigated for uniformly La-doped SrTiO_{3} films and GdTiO_{3}/SrTiO_{3} heterostructures, respectively. GdTiO_{3}/SrTiO_{3} interfaces exhibit a high-density 2D electron gas on the SrTiO_{3} side of the interface, while, for the SrTiO_{3} films, carriers are provided by the dopant atoms. Both types of samples exhibit ferromagnetism at low temperatures, as evidenced by a hysteresis in the magnetoresistance. For the uniformly doped SrTiO_{3} films, the Curie temperature is found to increase with doping and to coexist with superconductivity for carrier concentrations on the high-density side of the superconducting dome. The Curie temperature of the GdTiO_{3}/SrTiO_{3} heterostructures scales with the thickness of the SrTiO_{3} quantum well. The results are used to construct a stability diagram for the ferromagnetic and superconducting phases of SrTiO_{3}.

  11. 87 Sr/86 Sr anomalies in Late Cretaceous–Early Tertiary strata of ...

    Indian Academy of Sciences (India)

    Sr anomalies in Late Cretaceous–Early Tertiary strata of the Cauvery basin, south India: Constraints on nature and rate of environmental changes across K–T boundary. Mu Ramkumar Doris Stüben Zsolt Berner Jens Schneider. Volume 119 ...

  12. The Determination of 11 B/ 10 B and 87 Sr/ 86 Sr Isotope Ratios by ...

    African Journals Online (AJOL)

    In addition, the use of B isotope ratios together with elemental concentrations of selected indicator elements as independent variables in a linear discriminant analysis procedure was shown to be a highly successful method to classify wine according to geographical origin. A good correlation between the B and Sr isotope ...

  13. OpenSR: An Open-Source Stimulus-Response Testing Framework

    Directory of Open Access Journals (Sweden)

    Carolyn C. Matheus

    2015-01-01

    Full Text Available Stimulus–response (S–R tests provide a unique way to acquire information about human perception by capturing automatic responses to stimuli and attentional processes. This paper presents OpenSR, a user-centered S–R testing framework providing a graphical user interface that can be used by researchers to customize, administer, and manage one type of S–R test, the implicit association test. OpenSR provides an extensible open-source Web-based framework that is platform independent and can be implemented on most computers using any operating system. In addition, it provides capabilities for automatically generating and assigning participant identifications, assigning participants to different condition groups, tracking responses, and facilitating collecting and exporting of data. The Web technologies and languages used in creating the OpenSR framework are discussed, namely, HTML5, CSS3, JavaScript, jQuery, Twitter Bootstrap, Python, and Django. OpenSR is available for free download.

  14. Ivabradin and Verapamil Sr efficacy in treatment of coronary heart disease accompanied by bronchial obstructive diseases

    Directory of Open Access Journals (Sweden)

    Petrov V.I.

    2011-06-01

    Full Text Available The aim of the research is a comparative investigation of Ivabradin vs Verapamil SR of antianginal/antiischemic activity, physical exertion tolerance and life quality of patients with coronary heart disease (CHD accompanied by bronchial obstructive diseases. Parallel groups of patients have been examined for a 16-week period. Ivabradin (average dose — 14mg/day or Verapamil SR (average dose — 443mg/day were administered to ischemic patients (n=84 with postinfarction cardiosclerosis, stable angina (class l-ll and painless myocardial ischemia. Concomitant bronchial obstructive deseases included controlled/partly controlled bronchial asthma or chronic obstructive pulmonary disease (stage II-III. Both medications have demonstrated the same antianginal/antiischemic activity and have improved physical exertion tolerance. Ivabradin was more effective for heart rate (HR aim level and 24-hour HR control. Ivabradin advantages were more expressed by changing of NYHA class (from class II to class I and increase of 6MWD. In conclusion Ivabradin has demonstrated its effectiveness in life quality improvement. Ivabradin and Verapamil SR did not cause complications in concomitant asthma/COPD and were good tolerated. It was determined that Ivabradin is a good Verapamil SR alternative for CHD treatment in case of bronchial obstructive concomitant diseases

  15. Electrically tunable transport in antiferromagnetic Sr3Ir2O7

    Science.gov (United States)

    Seinige, Heidi; Wang, Cheng; Cao, Gang; Zhou, Jianshi-S.; Goodenough, John B.; Tsoi, Maxim

    Recently we demonstrated experimentally the existence of interconnections between magnetic state and transport currents in antiferromagnetic (AFM) Mott insulator Sr2IrO4. We found a very large anisotropic magnetoresistance and demonstrated a reversible resistive switching driven by high-density currents/high electric fields. These results support the feasibility of AFM spintronics, where antiferromagnets are used in place of ferromagnets, however a low Néel temperature of this material (240 K) questions any practical applications. Here we present a comparative electrical transport study of its sister compound Sr2IrO4 which has a higher transition temperature (285 K). Similar to the case of Sr2IrO4, we find a continuous reduction in the resistivity of Sr3Ir2O7 as a function of increasing electrical bias and abrupt reversible changes above a threshold bias current. We explain these results by a reduction of activation energy associated with a field-driven lattice distortion. This work was supported in part by C-SPIN, one of six centers of STARnet, a Semiconductor Research Corporation program, sponsored by MARCO and DARPA, and by NSF Grants DMR-1207577, DMR-1265162, and DMR-1122603.

  16. Rb-Sr and Sm-Nd Ages of Zagami DML and SR Isotopic Heterogeneity in Zagami

    Science.gov (United States)

    Nyquist, L.aurenceE.; Shih, C.-Y.; Reese, Y. D.

    2010-01-01

    Zagami contains lithologic heterogeneity suggesting that it did not form in a homogeneous, thick lava flow [1]. We have previously investigated the Sr and Nd isotopic systematics of Coarse-Grained (CG) and Fine-Grained (FG) lithologies described by [2]. Both appear to belong to Normal Zagami (NZ) [1,3], but their initial Sr-isotopic compositions differ [4,5]. Here we report new analyses of the Dark Mottled Lithology (DML, [3]) that show its age and initial Sr and Nd isotopic compositions to be identical within error limits with those of CG, but Sr initial isotopic compositions differ from those of FG.

  17. Ternary and quaternary oxides of Bi, Sr and Cu

    Science.gov (United States)

    Casais, M. T.; Millan, P.; Rasines, I.; Campa, J. A.

    1991-01-01

    Before the discovery of superconductivity in an oxide of Bi, Sr, and Cu, the system Bi-Sr-Cu-O had not been studied, although several solid phases had been identified in the two-component regions of the ternary system Bi2O3-Si-O-CuO. The oxides Sr2CuO3, SrCu2O2, SrCuO2, and Bi2CuO4 were then well known and characterized, and the phase diagram of the binary system Bi2O3-SrO had been established in the temperature range 620 to 1000 C. Besides nine solutions of compositions Bi(2-2x) Sr(x) O(3-2x) and different symmetries, this diagram includes three definite compounds of stoichiometries Bi(2)BrO4. Bi2Sr2O5, and Bi2Sr3O6 (x - 0.50, 0.67 and 0.75 respectively), only the second of which with known unit-cell of orthorhombic symmetry, dimensions (A) a = 14.293(2), b = 7.651(2), c = 6.172(1), and z = 4. The first superconducting oxide in the system Bi-Sr-Cu-O was initially formulated as Bi2Sr2Cu2O(7+x), with an orthorhombic unit-cell of parameters (A) a = 5.32, b = 26.6, c = 48.8. In a preliminary study the same oxide was formulated with half the copper content, Bi(2)Sr(2)CuO(6+x), and index its reflections assuming an orthorhombic unit-cell of dimensions (A) a = 5.390(2), b = 26.973(8), c = 24.69(4). Subsequent studies by diffraction techniques have confirmed the composition 2:2:1. A new family of oxygen-deficient perovskites, was characterized, after identifying by x ray diffraction the phases present in the products of thermal treatments of about 150 mixtures of analytical grade Bi2O3, Sr(OH)2-8H2O and CuO at different molar ratios. X ray diffraction data are presented for some other oxides of Bi and Sr, as well as for various quaternary oxides, among them an oxide of Bi, Sr, and Cu.

  18. Analysis on Mg/SrCO3 and Mg/Ba(ClO3)2 composition spectrum

    Science.gov (United States)

    Guo, Leju; Chen, Minghua; Chen, Yongkang; Shi, Tengfei

    2017-10-01

    Green light and red light pyrotechnic compound were measured with the whole-band radiometer in order to research the combustion performance. The Mg/SrCO3 and Mg/Ba(ClO3)2 composition spectrums and radiation intensities of the visible light were obtained by testing and calculating. Through researching combustion spectra of Mg/SrCO3 and Mg/Ba(ClO3)2 composition pyrotechnics, it can be concluded that both the combustion spectrum of Mg/SrCO3 and Mg/Ba(ClO3)2 composition are a mixed spectrum. The combustion spectrum of pyrotechnic compounds can be used as a means of identification of pyrotechnic composition.

  19. The Anatomy of Agenda-Setting Research.

    Science.gov (United States)

    Rogers, Everett M.; And Others

    1993-01-01

    Seeks to add insight to the complex intellectual history of agenda-setting research by identifying over-time patterns of publications and of bibliographic citations. Addresses issues about the past, present, and future of agenda-setting research. (SR)

  20. Magnetic two-dimensional electron gas at the manganite-buffered LaAlO3/SrTiO3 interface

    DEFF Research Database (Denmark)

    R. Zhang, H.; Zhang, Y.; Zhang, H.

    2017-01-01

    Fabrication of highly mobile spin-polarized two-dimensional electron gas (2DEG) is crucially important for both fundamental and applied research. Usually, spin polarization appears below 10 K for the 2DEG of LaAlO3/SrTiO3 interface, stemming from the magnetic ordering of Ti3+ ions with the mediat...... high. The magnetism likely results from a gradient manganese interdiffusion into SrTiO3. The present work demonstrates the great potential of manganite-buffered LaAlO3/SrTiO3 interfaces for spintronic applications....

  1. OpenNebula KVM SR-IOV driver

    CSIR Research Space (South Africa)

    Macleod, D

    2013-05-01

    Full Text Available With the recent release of an OFED which supports SR-IOV on Infiniband HCAs it is now possible to use verbs from inside a VM. This VMM driver supports these Infiniband HCAs, and any other SR-IOV network device, in OpenNebula....

  2. Geosphere process report for the safety assessment SR-Site

    Energy Technology Data Exchange (ETDEWEB)

    Skagius, Kristina (ed.) (Kemakta Konsult AB, Stockholm (Sweden))

    2010-11-15

    This report documents geosphere processes identified as relevant to the long-term safety of a KBS-3 repository, and forms an important part of the reporting of the safety assessment SR-Site. The detailed assessment methodology, including the role of the process reports in the assessment, is described in the SR-Site Main report /SKB 2011/

  3. Activity of strontium in Al-Sr liquid dilute solutions

    Energy Technology Data Exchange (ETDEWEB)

    Korc, B. (Warsaw Univ. of Technology, Dept. of Materials Science (Poland)); Panek, Z.; Fitzner, K. (Polish Academy of Sciences, Inst. of Metals Research, Cracow (Poland))

    1992-09-01

    The emf method employing concentration cells with liquid electrolyte and with liquid electrodes was used for the determination of strontium activity in liquid dilute Sr-Al solutions. Experiments were carried out on alloys of three different strontium mole fractions: X{sub Sr} = 0.01, 0.03 and 0.05, in the temperature range 973 to 1123 K. (orig.).

  4. Thermodynamic modeling of the Sr-Co-Fe-O system

    DEFF Research Database (Denmark)

    Zhang, Wei Wei; Povoden-Karadeniz, Erwin; Chen, Ming

    2016-01-01

    This paper reviews and assesses phase equilibria and thermodynamic properties of phases in the Sr-Co-Fe-O system, with a focus on oxides, especially the SrCo1 - xFexO3 - δ perovskite. In our work, the SrCo1 - xFexO3 - δ perovskite was modeled with a three-sublattice model, where the three sublatt...... composition optimization for various applications, including solid oxide fuel cells and oxygen membranes....... sublattices correspond to the A, B and oxygen sites in an ABO3 perovskite, respectively. A number of other important ternary oxide phases in Sr-Co-O and Sr-Co-Fe-O were also considered. Available thermodynamic and phase diagram data were carefully assessed. A thermodynamic description of Sr-Co-O was derived...... using the CALPHAD approach and was further extrapolated to that of Sr-Co-Fe-O. The thermodynamic database of Sr-Co-Fe-O established in this work allows for calculating phase diagrams, thermodynamic properties, cation distribution and defect chemistry properties, and therefore enables material...

  5. Variations in seawater Sr/Ca recorded in deep-sea bamboo corals

    Science.gov (United States)

    Hill, T. M.; Lavigne, M.; Spero, H. J.; Guilderson, T.; Gaylord, B.; Clague, D.

    2012-09-01

    A depth transect of deep-sea bamboo corals along the California margin provides evidence that coral strontium to calcium ratios (Sr/Cacoral) record seawater Sr/Ca ratios (Sr/Casw). A calibration was constructed utilizing Sr/Cacoral ratios and previously published Pacific Sr/Casw data (R2 = 0.53, n = 12, p < 0.01): Sr/Cacoral (mmol/mol) = 4.62*Sr/Casw (mmol/mol) - 36.64. Sr/Casw is ultimately governed by the remineralization of Sr-containing shells of surface water-derived marine organisms (e.g., Acantharia) at intermediate water depths. California margin Sr/Cacoral records from 792 and 1295 m document fluctuations in Sr/Casw that appear decadal-scale. These results suggest that Sr/Casw may not be as stable as previously assumed and may be influenced by surface productivity on short timescales.

  6. Electrophoretic deposition of chitosan/45S5 bioactive glass composite coatings doped with Zn and Sr

    Directory of Open Access Journals (Sweden)

    Marta eMiola

    2015-10-01

    Full Text Available In this research work the original 45S5 bioactive glass (BG was modified by introducing zinc and/or strontium oxide (6% mol in place of calcium oxide. Sr was added for its ability to stimulate bone formation, Zn for its role in bone metabolism, antibacterial properties and anti-inflammatory effect. The glasses were produced by means of melting and quenching process. SEM and XRD analyses evidenced that Zr and Sr introduction did not modify the glass structure and morphology, while compositional analysis (EDS demonstrated the effective addition of these elements inside the glass network. Bioactivity test in simulated body fluid (SBF up to one month evidenced a reduced bioactivity kinetics for Zn-doped glasses. Doped glasses were combined with chitosan to produce organic/inorganic composite coatings on stainless steel AISI 316L by electrophoretic deposition (EPD. Two EPD processes were considered for coating development, namely direct current EPD (DC-EPD and alternating current EPD (AC-EPD. The stability of the suspension was analysed and the deposition parameters were optimized. Tape and bending tests demonstrated a good coating-substrate adhesion for coatings containing 45S5-Sr and 45S5-ZnSr glasses, while the adhesion to the substrate decreased by using 45S5-Zn glass. FTIR analyses demonstrated the composite nature of coatings and SEM observations indicated that glass particles were well integrated in the polymeric matrix, the coatings were fairly homogeneous and free of cracks; moreover the AC-EPD technique provided better results than DC-EPD in terms of coating quality. SEM, XRD analyses and Raman spectroscopy, performed after bioactivity test in SBF solution, confirmed the bioactive behaviour of 45S5-Sr containing coating, while coatings containing Zn exhibited no hydroxyapatite formation.

  7. Laser cooling of SrOH and magneto-optical trapping of CaF

    Science.gov (United States)

    John Doyle, Harvard University

    2017-04-01

    Several promising goals of modern quantum science will be aided by the extension of precision control beyond atoms and bi-alkali molecules to a diverse set of molecular species with varying complex internal structures. Direct laser cooling and trapping of molecules is one promising route. For example, diatomic molecules with one or more unpaired electron spins and polyatomic molecules with closely spaced opposite parity levels have features advantageous for quantum simulation and precision measurement. Frontier research goals include the creation of new types of ultracold quantum molecular gases, optically trapped samples of molecules that can be read out and addressed individually, and new molecules for searches for particle physics beyond the standard model. Toward this goal, we have recently demonstrated laser slowing and magneto-optical trapping of CaF. Using a two stage cryogenic buffer-gas beam (CBGB) and white light slowing, more than 10,000 molecules are loaded and trapped in a MOT with a temperature below 10 mK. We create a `dual frequency' DC MOT as also demonstrated in and compare its properties to a RF MOT previously achieved with SrF. We will present our most recent progress with CaF. We have also recently demonstrated laser cooling of SrOH, a molecule whose structure illuminates some of the possibilities of ultracold polyatomic molecules. With three distinct vibrational modes, SrOH can be optically prepared in excited vibrational states resulting in nearly degenerate opposite parity levels that can be easily mixed in small electric fields. Using optical cycling, we have demonstrated Doppler and Sisyphus laser cooling of this polyatomic radical. By re-pumping the molecules that decay to the excited Sr-O stretching and bending modes, we reduce the transverse temperature of molecular beam from 50 mK to below 1 mK in one dimension. We will also present other recent work on SrOH. Our approach could be applied to more complex species like SrOCH3 and SrOCH2

  8. Tramadol SR in arthrosic and neuropathic pain.

    Science.gov (United States)

    Mariconti, P; Collini, R

    2008-03-01

    Chronic pain requires adequate treatment to control the severity of pain, allowing it to be well tolerated for the long term. Slow release formulations represent a useful method for the treatment of lasting pain because they allow for more simple pain management. The aim of this study was to verify the efficacy and tolerability of tramadol SR for the treatment of two of the most common kinds of chronic pain: arthrosic and neuropathic pain. A total of 100 patients (32 M/68 F), with a mean age of 61 years (+/-12) with non-oncologic pain (71 with arthrosic pain and 29 with neuropathic pain) were enrolled in an open prospective study. In most cases, the SR formulation of tramadol was prescribed at a dose of 100-200 mg/day; the initial follow-up appointments were two to four weeks later, and then at monthly intervals. During the study, a good analgesic response was recorded in all patients, irrespective of the type of pain they suffered. In fact, the intensity of the pain decreased rapidly and clearly, from severe (mean+SD 7.66+1.6 on an 11 point numerical scale) to mild residual pain (70.5% less than the baseline; P<0.05 between the times, NS between the groups), with pain relief and sleep quality displaying parallel improvement. Thus, all parameters of efficacy improved in both groups of patients, with no clinically important differences between the responses of the subjects with arthrosis and those of the subjects with neuropathic pain (P<0.05 between the times, NS between groups). Patient compliance was high. The tolerability was excellent in 75% of the patients. In the remaining 25%, the side effects that appeared were modest, as demonstrated by the fact that the drug was suspended in just 10 cases. These results confirm that the efficacy of tramadol in the treatment of neuropathic pain is also present in the SR formulation. The safety profile is reassuring, and, fundamentally, tramadol treatment only requires identification of the optimal dose without particular

  9. Targeting SR-BI for cancer diagnostics, imaging and therapy

    Directory of Open Access Journals (Sweden)

    Maneesha Amrita Rajora

    2016-09-01

    Full Text Available Scavenger receptor class B type I (SR-BI plays an important role in trafficking cholesteryl esters between the core of high density lipoprotein and the liver. Interestingly, this integral membrane protein receptor is also implicated in the metabolism of cholesterol by cancer cells, whereby overexpression of SR-BI has been observed in a number of tumours and cancer cell lines, including breast and prostate cancers. Consequently, SR-BI has recently gained attention as a cancer biomarker and exciting target for the direct cytosolic delivery of therapeutic agents. This brief review highlights these key developments in SR-BI-targeted cancer therapies and imaging probes. Special attention is given to the exploration of high density lipoprotein nanomimetic platforms that take advantage of upregulated SR-BI expression to facilitate targeted drug-delivery and cancer diagnostics, and promising future directions in the development of these agents.

  10. Geographical distribution of {sup 90}Sr contamination in Poland

    Energy Technology Data Exchange (ETDEWEB)

    Gaca, P.; Mietelski, J.W. [The Henryk Niewodniczanski Inst. of Nuclear Physics (IFJ PAN), Krakow (Poland); Skwarzec, B. [Univ. of Gdansk, Dept. of Chemistry, Gdansk (Poland)

    2006-07-01

    The paper presents results on determination of {sup 90}Sr in bilberry and cowberry leaves (Vaccinium myrtillus and Vaccinium vitis-idaea) and the use of these plants as bio-monitors of radiostrontium contamination in Poland. Radiostrontium was determined by mean of liquid scintillation spectrometry preceded by radiochemical separation using Sr-resin and {sup 85}Sr tracer. The approximate map of {sup 90}Sr contamination of Poland is presented. The activity ratio between {sup 90}Sr and obtained earlier data for {sup 137}Cs in the same samples is discussed. The enhancement of radiostrontium content observed in northeastern Poland seems to be the trace of hot-particles fallout from initial Chernobyl cloud, which passed over Polish territory toward Scandinavia. (orig.)

  11. Experimental Evaluation of Characteristics of SR Motor Made of Permendur

    Science.gov (United States)

    Hasegawa, Yu; Nakamura, Kenji; Ichinokura, Osamu

    A switched reluctance (SR) motor has a doubly salient pole structure. The performance of the SR motor strongly depends on the magnetic properties of the core material since it consists only of an iron core and copper windings. This study experimentally evaluates the performance of an SR motor made of permendur (Fe-49%Co alloy), which has very high saturation flux density and low core loss. Two types of SR motors that have the same dimensions but different core materials are used: one motor is made of the conventional non-oriented Si steel, and the other is made of permendur. Comparison of the characteristics of the two motors shows that the performance of the permendur SR motor surpasses that of the conventional one in terms of output power and efficiency.

  12. Expert Opinion in SR 97 and the SKI/SSI Joint Review of SR 97

    Energy Technology Data Exchange (ETDEWEB)

    Hora, Stephen

    2002-09-01

    The role of sensitivity and uncertainty analyses for radioactive waste disposal assessments is reviewed. The report covers a description of the these concepts were applied in the authorities' review of the safety report SR 97. With regard to the use of expert knowledge, the most significant weakness of SR 97 is absence of any standards, procedures, and even definitions for expert judgment. This situation needs to be dealt with by SKB in the near future as it denigrates the portions of the study that are well done. In developing expert judgment processes, SSI should ensure that SKB creates procedures that guarantee traceability and transparency. This will become very important as the repository system matures and receives greater public scrutiny. Both in the area of scenario creation and expert judgement, there are processes that have gained international acceptance. It would be in the best interest of SKB, and the public, to adhere these accepted approaches.

  13. MuSR Beam Line Design Studies

    Energy Technology Data Exchange (ETDEWEB)

    MacKay, W. W. [Weirich Consulting Services, Inc. Hunterville, NC (United States); Fischer, W. [Brookhaven National Lab. (BNL), Upton, NY (United States); Pile, P. [Brookhaven National Lab. (BNL), Upton, NY (United States); Blaskiewicz, M. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2013-12-13

    When a substance is implanted with positive muons the precession of their magnetic moments can be used to sample the magnetic properties of the material. The information obtained is complementary to that from NMR, ESR, and neutron scattering. To date, only four user facilities exist in the world but none in the US. We explore the possibility of using the AGS complex at BNL for a μSR facility for the production of positive surface muons. With an incident proton intensity of 1014 protons per second hitting a 200 mm long 0.5 mm thick graphite target, our preliminary design of the beam line could produce low momentum surface muons (24–30 MeV/c) with a flux of 0.9 MHz/cm2 for experiments.

  14. In situ Sr/Sr investigation of igneous apatites and carbonates using laser-ablation MC-ICP-MS

    DEFF Research Database (Denmark)

    Bizzarro, Martin; Simonetti, A.; Stevenson, R.K.

    2003-01-01

    In situ Sr isotopic compositions of coexisting apatite and carbonate for carbonatites from the Sarfartoq alkaline complex, Greenland, have been determined by laser-ablation multicollector inductively coupled plasma mass spectrometry. This study is the first to examine the extent of Sr isotopic...

  15. Strontium (87Sr/86Sr) dating of marine shells from pliocene and pleistocene shallow marine deposits in The Netherlands

    NARCIS (Netherlands)

    Jansen, H.S.M.; Huizer, J.; Dijkmans, J.W.A.; Hinte, J.E. van

    2004-01-01

    87Sr/86Sr (Strontium) ratio analyses of shell material (mainly Arctica islandica) from 24 levels in the Maassluis Formation of boreholes Noordwijk, Zegveld and Terschelling suggest that the age of the formation ranges from 0.82 to 2.34 Ma (± 0.5 Ma), and that the Oosterhout Formation at Noordwijk

  16. Rb-Sr and Nd-Sr isotope geochemistry and petrogenesis of the Misho Mountains mafic dikes (NW Iran

    Directory of Open Access Journals (Sweden)

    Maryam Ahankoub

    2017-02-01

    Full Text Available Introduction There are some theories about the Paleotethys event during the Paleozoic that have been proposed by geologists (Metcalfe, 2006. Some scientist offered some pieces of evidence about the northern margin of Gondwana (Zhu et al., 2010. The Paleotethys Ocean and Hercynian orogenic report first in Iran, have been Offered from the Morrow and Misho Mountain (Eftekharnejad, 1981. Misho Mountains is located between the north and south Misho faults and cause the formation of a positive flower structure (Moayyed and Hossainzade, 2011. There is theory about Misho southern fault as the best candidate of the Paleotethys suture zone (Moayyed and Hossainzade, 2011. Geochemistry and Sr –Nd isotopic data of the A2 granitic and Synite rocks of the East Misho, indicate that the magmatism post collision has occurred in the active continental margin by extensional zones of the following the closure of the Paleotethys (Ahankoub, 2012. Granite and syenite rocks have been cut by mafic dikes. Mafic dikes are often formed in extensional tectonic settings related to mantle plume or continental break –up (Zhu et al., 2009. In this paper, we use the geochemistry and Nd-Sr isotope data to determined petrogenesis, tectono-magmatic setting and age of Misho mafic dikes. Materials and methods After petrography study of 30 thin sections of mafic dike rocks, 8 samples were selected for whole-rock chemical analyses using ICP-MS and ICP-AES instruments by ACME Company in Vancouver, Canada. We prepared 6 sample For Sm-Nd and Rb-Sr analysis. Sr and Nd isotope ratios were measured with a thermal ionization mass spectrometer, VG Sector 54–30 at the Nagoya University. The isotope abundances of Rb, Sr, Nd, and Sm were measured by the ID method with a Finnigan MAT Thermoquad THQ thermal ionization quadrupole mass spectrometer at the Nagoya University. NBS987 and JNdi-1 were measured as natural Sr and Nd isotope ratio standards (Tanaka et al., 2000. Averages and 2σ errors

  17. Factor structure, reliability, and validity of the Japanese version of the Hoarding Rating Scale-Self-Report (HRS-SR-J

    Directory of Open Access Journals (Sweden)

    Tsuchiyagaito A

    2017-05-01

    Full Text Available Aki Tsuchiyagaito,1–3 Satoshi Horiuchi,4 Toko Igarashi,5 Yoshiya Kawanori,4 Yoshiyuki Hirano,1,3 Hirooki Yabe,2 Akiko Nakagawa1,3 1Research Center for Child Mental Development, Chiba University, Chiba, 2Department of Neuropsychiatry, Fukushima Medical University, Fukushima, 3United Graduate School of Child Development, Osaka University, Kanazawa University, Hamamatsu University School of Medicine, Chiba University and University of Fukui, Osaka, 4Faculty of Social Welfare, Iwate Prefectural University, Iwate, 5Graduate School of Education, Joetsu University of Education, Niigata, Japan Background: The Hoarding Rating Scale-Self-Report (HRS-SR is a five-item scale that assesses the symptoms of hoarding. These symptoms include excessive acquisition, difficulty in discarding, and excessive clutter that causes distress. We conducted three studies to examine the factor structure, reliability, and validity of the Japanese version of the HRS-SR (HRS-SR-J. Methods: Study 1 examined its reliability; 193 college students and 320 adolescents and adults completed the HRS-SR-J and, of the college students, 32 took it again 2 weeks later. Study 2 aimed to confirm that its scores in a sample of 210 adolescents and adults are independent of social desirability. Study 3 aimed to validate the HRS-SR-J in the aspects of convergent and discriminant validity in a sample of 550 adults. Results: The HRS-SR-J showed good internal consistency and 2-week test–retest reliability. Based on the nonsignificant correlations between the HRS-SR-J and social desirability, the HRS-SR-J was not strongly affected by social desirability. In addition, it also had a good convergent validity with the Japanese version of the Saving Inventory-Revised (SI-R-J and the hoarding subscale of the Obsessive-Compulsive Inventory, while having a significantly weaker correlation with the five subscales of the Obsessive-Compulsive Inventory, except for the hoarding subscale. In addition, the

  18. Fabrication of bimodal-pore SrTiO3 microspheres with excellent photocatalytic performance for Cr(VI) reduction under simulated sunlight.

    Science.gov (United States)

    Yang, Dong; Sun, Yuanyuan; Tong, Zhenwei; Nan, Yanhu; Jiang, Zhongyi

    2016-07-15

    Solving the increasing contamination from toxic heavy metal ions in wastewater is an imperative issue in photocatalysis research area. In this study, three-dimensional (3D) porous SrTiO3 microspheres have been fabricated by a sol-gel-templating method using the agarose gel bead containing SrCO3 granules as the template. The resultant SrTiO3 microspheres, several tens of micrometers in diameter, exhibit a bimodal pore structure, in which the macropore about 70-150nm in size stems from SrCO3 granules and the mesopore about 3nm is formed via removing the agarose fiber embedded in the composite microspheres. The porous framework of SrTiO3 microspheres is assembled by regular single-crystalline SrTiO3 nanocubes with an edge length of 100±10nm. The highly interconnected porous network renders numerous pathways for the rapid mass transport, strong adsorption of reactants and multi-reflection of incident light. Moreover, the as-prepared SrTiO3 microspheres exhibit excellent photocatalytic performance for the Cr(VI) reduction under simulated sunlight, which can reduce nearly 100% Cr(VI) at pH 2 within 2h and retain a relatively high reduction ability after six recycles. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Rare earth elements and (87)Sr/(86)Sr isotopic characterization of Indian Basmati rice as potential tool for its geographical authenticity.

    Science.gov (United States)

    Lagad, Rupali A; Singh, Sunil K; Rai, Vinai K

    2017-02-15

    The increasing demand for premium priced Indian Basmati rice (Oryza sativa) in world commodity market causing fraudulent activities like adulteration, mislabelling. In order to develop authentication method for Indian Basmati rice, (87)Sr/(86)Sr ratios and REEs composition of Basmati rice, soil and water samples were determined and evaluated their ability as geographical tracer in the present study. In addition, the possible source of Sr in rice plant has also been examined. Basmati rice samples (n=82) showed (87)Sr/(86)Sr ratios in the range 0.71143-0.73448 and concentrations of 10 REEs (La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Er, Yb) in ppb levels. Statistical analysis showed strong correlation between (87)Sr/(86)Sr ratios of rice, silicate and carbonate fractions of soil. Good correlation and closeness of (87)Sr/(86)Sr of rice with water indicate its uptake in rice from water. Rice grown in southern Uttar Pradesh contains higher (87)Sr/(86)Sr compared to other region of Indo-Gangetic Plain due to higher (87)Sr/(86)Sr of the Ganga compared to other rivers. (87)Sr/(86)Sr ratios can be used as a tracer for differentiating Indian Basmati rice from the other country originated rice samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. The evolution of the 87Sr/86Sr in the Dead Sea brine: from the Sedom lagoon to Sahara dusts

    Science.gov (United States)

    Stein, Mordechai

    2016-04-01

    The history of water-bodies in the Dead Sea brines commenced with the intrusion of the Sedom lagoon, possibly in the late Neogene and continued with the development of hypersaline and freshwater lakes (e.g. the modern Dead Sea and Sea of Galilee). 87Sr/86Sr ratios in these water-bodies decreased over the past ~ 5-6 Ma from 0.7087-0.7084 in salts deposited in the Sedom lagoon to ~ 0.7080 in modern Dead Sea brine. The 87Sr/86Sr ratios in the salts deposited from Sedom lagoon are significantly lower than those of the contemporaneous late Miocene seawater (~0.709). This difference was attributed to modification of the 87Sr/86Sr ratio in the Sedom lagoon solution by influx of Ca-chloride brines. The brines, in turn were formed by dolomitization of marine limestones of the DSR Cretaceous wall rocks (87Sr/86Sr ~ 0.7075) by the ingressing evaporated seawaters (Stein et al., 2000). After the disconnection of the Sedom lagoon from the open sea freshwater filled the lakes that occupied the Dead Sea basin. The freshwater influx modified the strontium isotope and chemical composition of the brine and provided bicarbonate and sulfate to the lake that led the precipitation of primary aragonite and gypsum. Freshwater that currently enter the lake are characterize by 87Sr/86Sr ~ 0.7081, significantly higher than the Cretaceous carbonates. Settled dust that deposits on the Judea Mountains is composed of calcite and quartz grains and is characterized by 87Sr/86Sr ratios ~ 0.7084. It appears that significant amounts of the strontium that entered the lakes with the freshwater originated from dissolution of the dust calcites. Large amounts of dust were transported from the Sahara desert to the Dead Sea watershed during glacial periods when the Sahara was dry and sea-level was low. The source of the detrital calcites however, is not known. They could be derived from dry paleo-lakes in the Sahara that were previously filled by waters that retained the required strontium isotope

  1. Interactions of SR45, an SR-like protein, with spliceosomal proteins and an intronic sequence: insights into regulated splicing.

    Science.gov (United States)

    Day, Irene S; Golovkin, Maxim; Palusa, Saiprasad G; Link, Alicia; Ali, Gul S; Thomas, Julie; Richardson, Dale N; Reddy, Anireddy S N

    2012-09-01

    SR45 is a serine/arginine-rich (SR)-like protein with two arginine/serine-rich (RS) domains. We have previously shown that SR45 regulates alternative splicing (AS) by differential selection of 5' and 3' splice sites. However, it is unknown how SR45 regulates AS. To gain mechanistic insights into the roles of SR45 in splicing, we screened a yeast two-hybrid library with SR45. This screening resulted in the isolation of two spliceosomal proteins, U1-70K and U2AF(35) b that are known to function in 5' and 3' splice site selection, respectively. This screen not only confirmed our prior observation that U1-70K and SR45 interact, but also helped to identify an additional interacting partner (U2AF(35) ). In vitro and in vivo analyses revealed an interaction of SR45 with both paralogs of U2AF(35) . Furthermore, we show that the RS1 and RS2 domains of SR45, and not the RNA recognition motif (RRM) domain, associate independently with both U2AF(35) proteins. Interaction studies among U2AF(35) paralogs and between U2AF(35) and U1-70K revealed that U2AF(35) can form homo- or heterodimers and that U2AF(35) proteins can associate with U1-70K. Using RNA probes from SR30 intron 10, whose splicing is altered in the sr45 mutant, we show that SR45 and U2AF(35) b bind to different parts of the intron, with a binding site for SR45 in the 5' region and two binding regions, each ending with a known 3' splice site, for U2AF(35) b. These results suggest that SR45 recruits U1snRNP and U2AF to 5' and 3' splice sites, respectively, by interacting with pre-mRNA, U1-70K and U2AF(35) and modulates AS. © 2012 The Authors. The Plant Journal © 2012 Blackwell Publishing Ltd.

  2. Bioremediation of strontium (Sr) contaminated aquifer quartz sand based on carbonate precipitation induced by Sr resistant Halomonas sp.

    Science.gov (United States)

    Achal, Varenyam; Pan, Xiangliang; Zhang, Daoyong

    2012-10-01

    Contamination of aquifers or sediments by radioactive strontium ((90)Sr) is a significant environmental problem. In the present study, microbially induced calcite precipitation (MICP) was evaluated for its potential to remediate strontium from aquifer quartz sand. A Sr resistant urease producing Halomonas sp. was characterized for its potential role in bioremediation. The bacterial strain removed 80% of Sr from soluble-exchangeable fraction of aquifer quartz sand. X-ray diffraction detected calcite, vaterite and aragonite along with calcite-strontianite (SrCO(3)) solid solution in bioremediated sample with indications that Sr was incorporated into the calcite. Scanning electron micrography coupled with energy-dispersive X-ray further confirmed MICP process in remediation. The study showed that MICP sequesters soluble strontium as biominerals and could play an important role in strontium bioremediation from both ecological and greener point of view. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Luminescence and absorbance of highly crystalline CaMoO{sub 4}, SrMoO{sub 4}, CaWO{sub 4} and SrWO{sub 4} nanoparticles synthesized by co-precipitation method at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Thongtem, Titipun, E-mail: ttpthongtem@yahoo.co [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Kungwankunakorn, Sukjit [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Kuntalue, Budsabong [Electron Microscopy Research and Service Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Phuruangrat, Anukorn, E-mail: phuruangrat@hotmail.co [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Thongtem, Somchai [Department of Physics and Materials Science, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand)

    2010-09-10

    Research highlights: In this research, we synthesized the highly crystalline CaMoO{sub 4}, SrMoO{sub 4}, CaWO{sub 4} and SrWO{sub 4} nanoparticles by solution route method using M(NO{sub 3}){sub 2{center_dot}}2H{sub 2}O (M = Ca and Sr) and Na{sub 2}XO{sub 4{center_dot}}2H{sub 2}O (X = Mo and W) in ethylene glycol as solution at room temperature under stirred 24 h. The phases, morphologies, atom vibrate interaction and optical properties of products were analyzed by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform inferred spectroscopy (FTIR), Raman spectroscopy and UV-visible spectroscopy, respectively. This method is a novel and simple than the previous reports. - Abstract: Highly crystalline CaMoO{sub 4}, SrMoO{sub 4}, CaWO{sub 4} and SrWO{sub 4} nanoparticles were successfully synthesized by the co-precipitation of mixtures of Ca(NO{sub 3}){sub 2{center_dot}}4H{sub 2}O or Sr(NO{sub 3}){sub 2}, and Na{sub 2}MoO{sub 4{center_dot}}2H{sub 2}O or Na{sub 2}WO{sub 4{center_dot}}2H{sub 2}O dissolved in ethylene glycol at room temperature (30 {sup o}C). Phases, morphologies, atomic vibrations and optical properties were analyzed by X-ray diffraction, transmission electron microscopy, Fourier transform infrared and Raman spectrophotometry, and ultraviolet-visible and photoluminescent spectroscopy. All products were proved to be MXO{sub 4} (M = Ca and Sr, and X = Mo and W) with body-centered tetragonal scheelite structures, having round nanoparticles with the average sizes of 12.06 {+-} 1.65, 16.40 {+-} 2.44, 15.49 {+-} 2.19, and 15.40 {+-} 2.30 nm for CaMoO{sub 4}, SrMoO{sub 4}, CaWO{sub 4} and SrWO{sub 4}, respectively. Their {nu}{sub 1}(A{sub g}), {nu}{sub 3}(B{sub g}), {nu}{sub 3}(E{sub g}), {nu}{sub 4}(B{sub g}), {nu}{sub 2}(A{sub g}) and {nu}{sub f.r.}(A{sub g}) vibration modes were also detected - being shifted to lower wavenumbers from MMoO{sub 4} to MWO{sub 4}, due to the change of efficient atomic mass of the oscillating ions

  4. Modificación estructural de la lignina extraída a partir de carbones de bajo rango para la obtención de madera sintética

    Directory of Open Access Journals (Sweden)

    Jesús Álvaro Jiménez Montoya

    2011-06-01

    Full Text Available The Universidad Distrital Francisco José de Caldas Coal Research Group has been working with lignin extraction from peat and low rank coal and using the obtained extract for synthetic wood industry. Sosa, sulfate and bisulfite methods [1] were applied in the first research step and later they were modified with the lignine extraction process from pine and cedar. Among these, Sosa method showed asthe more efficient method, so, it was used to extract lignine from low rank coal. The extracted lignin was used to prepare lignin-phenol-formaldehide resin and it works as natural fiber binder [2].In the second research step, standarization Sosa method was made [3], were pressure was modified using an pressure reactor (autoclave for a peat sample. Efficiency was improved. The obtained lignine was used to prepare resins such as phenolformaldehide- lignin, resorcinol-formaldehydelignin and polypropilen-lignin. All of them were utilized using sugar cane bagasse as natural fiber. Currently, a third research step is being developed using Sosa method and working with a peat sample.The main purpose, is to modificate the extracted lignin structure by UV radiation (physical methot and with NaOH (Chemical method so the lignin reactivity is improved in the resins production [4] and as result, to get a better quality synthetic wood.

  5. Changes in local surface structure and Sr depletion in Fe-implanted SrTiO{sub 3} (001)

    Energy Technology Data Exchange (ETDEWEB)

    Lobacheva, O., E-mail: olobache@gmail.com [Department of Physics and Astronomy, Western University, London, ON N6A 5B7 (Canada); Yiu, Y.M. [Department of Chemistry, Western University, London, ON N6A 5B7 (Canada); Chen, N. [Canadian Light Source, Saskatoon, SK S7N 0X4 (Canada); Sham, T.K.; Goncharova, L.V. [Department of Physics and Astronomy, Western University, London, ON N6A 5B7 (Canada); Department of Chemistry, Western University, London, ON N6A 5B7 (Canada)

    2017-01-30

    Highlights: • Fe ion implantation of SrTiO{sub 3} and post-implantation results in formation of Sr{sub 1-y}Ti{sub 1-x}Fe{sub x+y}O{sub 3-δ} phase. • In Sr{sub 1-y}Ti{sub 1-x}Fe{sub x+y}O{sub 3-δ} phase, Fe assumes Fe{sup 3+} oxidation state in the bulk and Fe{sup 2+} oxidation state in the near surface area. • FEFF9 calculations indicate that Fe ions can substitute both Ti and Sr sites. • Formation of Sr{sub 1-y}Ti{sub 1-x}Fe{sub x+y}O{sub 3-δ} phase is accompanied by Sr depletion in the near surface region. - Abstract: Local surface structure of single crystal strontium titanate SrTiO{sub 3} (001) samples implanted with Fe in the range of concentrations between 2 × 10{sup 14} to 2 × 10{sup 16} Fe/cm{sup 2} at 30 keV has been investigated. In order to facilitate Fe substitution (doping), implanted samples were annealed in oxygen at 350 °C. Sr depletion was observed from the near-surface layers impacted by the ion-implantation process, as revealed by Rutherford Backscattering Spectrometry (RBS), X-ray photoelectron spectroscopy (XPS), X-ray Absorption Near Edge Spectroscopy (XANES), and Atomic Force Microscopy (AFM). Hydrocarbon contaminations on the surface may contribute to the mechanisms of Sr depletion, which have important implications for Sr(Ti{sub 1-x}Fe{sub x})O{sub 3-δ} materials in gas sensing applications.

  6. Densification and dielectric properties of SrO–Al2O3–B2O3 ceramic ...

    Indian Academy of Sciences (India)

    The addition of B2O3 and SrO significantly reduced the sintering temperature of alumina ceramic bodies to 1600°C with optimum density (∼ 4 g/cm3) as compared with pure alumina powders recycled from Al dross (3.55 g/cm3 sintered at ... Ceramic Department, National Research Centre, 12622 Dokki, Cairo, Egypt ...

  7. How Perception Guides Action: Figure-Ground Segmentation Modulates Integration of Context Features into S-R Episodes

    Science.gov (United States)

    Frings, Christian; Rothermund, Klaus

    2017-01-01

    Perception and action are closely related. Responses are assumed to be represented in terms of their perceptual effects, allowing direct links between action and perception. In this regard, the integration of features of stimuli (S) and responses (R) into S-R bindings is a key mechanism for action control. Previous research focused on the…

  8. Strongly Misaligned Triple System in SR 24 Revealed by ALMA

    Science.gov (United States)

    Fernández-López, M.; Zapata, L. A.; Gabbasov, R.

    2017-08-01

    We report the detection of the 1.3 mm continuum and the molecular emission of the disks of the young triple system SR24 by analyzing ALMA (The Atacama Large Millimeter/Submillimter Array) subarcsecond archival observations. We estimate the mass of the disks (0.025 M ⊙ and 4 × 10-5 M ⊕ for SR24S and SR24N, respectively) and the dynamical mass of the protostars (1.5 M ⊙ and 1.1 M ⊙). A kinematic model of the SR24S disk to fit its C18O (2-1) emission allows us to develop an observational method to determine the tilt of a rotating and accreting disk. We derive the size, inclination, position angle, and sense of rotation of each disk, finding that they are strongly misaligned (108^\\circ ) and possibly rotate in opposite directions as seen from Earth, in projection. We compare the ALMA observations with 12CO SMA archival observations, which are more sensitive to extended structures. We find three extended structures and estimate their masses: a molecular bridge joining the disks of the system, a molecular gas reservoir associated with SR24N, and a gas streamer associated with SR24S. Finally, we discuss the possible origin of the misaligned SR24 system, concluding that a closer inspection of the northern gas reservoir is needed to better understand it.

  9. New methodology for a faster synthesis of SrSnO3 by the modified Pechini method

    Directory of Open Access Journals (Sweden)

    G. L. Lucena

    2013-06-01

    Full Text Available SrSnO3, a perovskite-type complex oxide, was synthesized by the modified Pechini method using two different precursors, tin chloride and metallic tin. The first one is already traditional in the literature and it claims about 30 days, only for the cleaning of tin citrate aiming at the elimination of the chloride. The second route was developed by our research group and saves time, taking 6 h to complete the synthesis of the resin. The results show that SrSnO3 obtained from the metallic tin show a higher short range order, leading to a band gap value higher than those reported in the literature, besides a meaningful reduction in the formation of SrCO3, as compared to the one obtained from tin chloride.

  10. Development of a web-based DICOM-SR viewer for CAD data of multiple sclerosis lesions in an imaging informatics-based efolder

    Science.gov (United States)

    Ma, Kevin; Wong, Jonathan; Zhong, Mark; Zhang, Jeff; Liu, Brent

    2014-03-01

    In the past, we have presented an imaging-informatics based eFolder system for managing and analyzing imaging and lesion data of multiple sclerosis (MS) patients, which allows for data storage, data analysis, and data mining in clinical and research settings. The system integrates the patient's clinical data with imaging studies and a computer-aided detection (CAD) algorithm for quantifying MS lesion volume, lesion contour, locations, and sizes in brain MRI studies. For compliance with IHE integration protocols, long-term storage in PACS, and data query and display in a DICOM compliant clinical setting, CAD results need to be converted into DICOM-Structured Report (SR) format. Open-source dcmtk and customized XML templates are used to convert quantitative MS CAD results from MATLAB to DICOM-SR format. A web-based GUI based on our existing web-accessible DICOM object (WADO) image viewer has been designed to display the CAD results from generated SR files. The GUI is able to parse DICOM-SR files and extract SR document data, then display lesion volume, location, and brain matter volume along with the referenced DICOM imaging study. In addition, the GUI supports lesion contour overlay, which matches a detected MS lesion with its corresponding DICOM-SR data when a user selects either the lesion or the data. The methodology of converting CAD data in native MATLAB format to DICOM-SR and displaying the tabulated DICOM-SR along with the patient's clinical information, and relevant study images in the GUI will be demonstrated. The developed SR conversion model and GUI support aim to further demonstrate how to incorporate CAD post-processing components in a PACS and imaging informatics-based environment.

  11. PRODUCTION OF PLANTARCIN BY LACTOBACILLUS PLANTARUM SR18

    Directory of Open Access Journals (Sweden)

    Wagih El-Shouny

    2012-06-01

    Full Text Available Out of 86 lactobacilli previously screened in our laboratory, Lactobacillus plantarum SR18 isolated from yoghurt revealed the largest detected inhibition zone against the selected indicator Streptococcus salivarius 5. The obtained electrophoretic patterns revealed that L. plantarum SR18 was free from plasmids. Exposure of 6 h growing L. plantarum culture to T-8M, 3B ultraviolet B lamp (8w, 220v & 312 nm for 2 h and subsequent growth for further 24 h resulted in an increase of cell-bound bacteriocin titer reached 2 fold at 12 h. Whereas bacteriocin secreted in the culture filtrate was not affected by UV irradiation. Plantarcin SR18 production was maximal (12800 AU/ml between 12 and 18 h by incubation of the culture at 37°C and pH 5-7 in candle jar (CO2. The bacteriocin bound to the cells and that secreted into the culture filtrate of L. plantarum SR18 were precipitated by 75% ammomium sulphate, dialysed and further purified by Gel filtration on Sephadex G-100. The specific activities (AU/mg protein were increased by a factor of about 5.3 and 2.35 for plantarcins purified from proteins bound to the cell of L. plantarum SR18 (plantarcin SR18 a and that secreted into the culture filtrate (plantarcin SR18 b, respectively. Gel filtration of plantarcin SR18a resulted in moderate antibacterial activity (3200 AU/ml and very high activity (25600 AU/ml of plantarcin SR18b.

  12. Numerical solutions of anharmonic vibration of BaO and SrO molecules

    Science.gov (United States)

    Pramudito, Sidikrubadi; Sanjaya, Nugraha Wanda; Sumaryada, Tony

    2016-03-01

    The Morse potential is a potential model that is used to describe the anharmonic behavior of molecular vibration between atoms. The BaO and SrO molecules, which are two almost similar diatomic molecules, were investigated in this research. Some of their properties like the value of the dissociation energy, the energy eigenvalues of each energy level, and the profile of the wavefunctions in their correspondence vibrational states were presented in this paper. Calculation of the energy eigenvalues and plotting the wave function's profiles were performed using Numerov method combined with the shooting method. In general we concluded that the Morse potential solved with numerical methods could accurately produce the vibrational properties and the wavefunction behavior of BaO and SrO molecules from the ground state to the higher states close to the dissociation level.

  13. The influence of pressing conditions on SrFe12O19 nano-particles

    DEFF Research Database (Denmark)

    Mortensen, Anna; Stingaciu, Marian; Christensen, Mogens

    2015-01-01

    The influence of pressing conditions on SrFe12O19 nano-particles Anna Zink Mortensen, Marian Stingaciu, Mogens Christensen Aarhus University Permanent magnets have great importance for many technological applications. Today researchers try making new and cheap magnets without rare earth elements....... Strontium hexaferrite, SrFe12O19, is an important permanent magnet because of its large anisotropy, good performance/cost ratio, and high stability. By hydrothermal synthesis platelet-like single-domain nanoparticles can be made. It is possible to control the particle sizes varying time, temperature......, and pressure which highly influence the magnetic properties. The platelet-like particles makes it possible to align the powder in the same direction giving a higher net magnetization. One challenge is to optimize the pressing conditions in order to maximize the remanence and thus the energy product. In present...

  14. The design and integration of retinal CAD-SR to diabetes patient ePR system

    Science.gov (United States)

    Wu, Huiqun; Wei, Yufang; Liu, Brent J.; Shang, Yujuan; Shi, Lili; Jiang, Kui; Dong, Jiancheng

    2017-03-01

    Diabetic retinopathy (DR) is one of the serious complications of diabetes that could lead to blindness. Digital fundus camera is often used to detect retinal changes but the diagnosis relies too much on ophthalmologist's experience. Based on our previously developed algorithms for quantifying retinal vessels and lesions, we developed a computer aided detection-structured report (CAD-SR) template and implemented it into picture archiving and communication system (PACS). Furthermore, we mapped our CAD-SR into HL7 CDA to integrate CAD findings into diabetes patient electronic patient record (ePR) system. Such integration could provide more quantitative features from fundus image into ePR system, which is valuable for further data mining researches.

  15. Magnetism in the p-type Monolayer II-VI semiconductors SrS and SrSe

    Science.gov (United States)

    Lin, Heng-Fu; Lau, Woon-Ming; Zhao, Jijun

    2017-01-01

    Using density functional theory calculations, we study the electronic and magnetic properties of the p-type monolayer II-VI semiconductors SrX (X = S,Se). The pristine SrS and SrSe monolayers are large band gap semiconductor with a very flat band in the top valence band. Upon injecting hole uniformly, ferromagnetism emerges in those system in a large range of hole density. By varying hole density, the systems also show complicated phases transition among nonmagnetic semiconductor, half metal, magnetic semiconductor, and nonmagnetic metal. Furthermore, after introducing p-type dopants in SrS and SrSe via substitutionary inserting P (or As) dopants at the S (or Se) sites, local magnetic moments are formed around the substitutional sites. The local magnetic moments are stable with the ferromagnetic order with appreciable Curie temperature. The ferromagnetism originates from the instability of the electronic states in SrS and SrSe with the large density of states at the valence band edge, which demonstrates a useful strategy for realizing the ferromagnetism in the two dimensional semiconductors. PMID:28378761

  16. SR ( Science and Religion SEBAGAI PENDEKATAN PEMBELAJARAN BIOLOGI PADA KURIKULUM 2013 UNTUK MENINGKATKAN KARAKTER SISWA

    Directory of Open Access Journals (Sweden)

    Nur Khasanah

    2017-05-01

    Full Text Available  ABSTRACTThe learning activities is a process of discovery and experience so that the knowledge can improve students' understanding and the character. Science is often identified with the West. The Islamic education is often oriented to the future life tend to be defensive. Approach of Science and Religion (SR is a combination of approaches concepts, process skills, inquiry, and discovery and approaches to religious values. The philosophy underlying the approach is a constructivist approach behavioristik SR, learners formulate their own concepts in cognitive structure based on their knowledge then implement the values that exist in the community surrounding and religious values. Subject of this research was a 45 students of MAN 1 Semarang academic year 2015-2016 Research was conducted in odd semester of 2015, include: 1 planning, 2 implementation, 3 observation,   and4 evaluation. The results showed a good indicator of student activity in the learning lab and discussions has been reached on the completeness of classical study on lab activities amounted to 82.44% with an average value of 81.48 liveliness, and discussions 81.86% with an average value of 82, 10 (criteria very well. Indicators student's character visits of religious attitudes, responsibility, honesty, respect, discipline, and self-contained. The conclusion were a. SR approach seeks to provide an understanding of How teach science by providing a vision of Islam in the classroom. b. SR approach applied to the learning process Biology can apply knowledge and improve the character of the students.

  17. Lacustrine 87Sr/86Sr as a tracer to reconstruct Milankovitch forcing of the Eocene hydrologic cycle

    Science.gov (United States)

    Baddouh, M'bark; Meyers, Stephen R.; Carroll, Alan R.; Beard, Brian L.; Johnson, Clark M.

    2016-08-01

    The Green River Formation (GRF) provides one of the premier paleoclimate archives of the Early Eocene Climatic Optimum (∼50 Ma), representing the apex of the early Cenozoic greenhouse climate. Rhythmic lake-level variability expressed in the GRF has inspired numerous hypotheses for the behavior of the Eocene hydrologic cycle, including its linkage to astronomical forcing, solar variability, and the El Niño Southern Oscillation (ENSO). However, the lack of sufficient proxy data to document atmospheric water-mass transport and the geographic pattern of evaporation/precipitation/runoff has made it difficult to discriminate between different models for astronomical forcing. Variable 87Sr/86Sr ratios of bedrock that encompass the GRF provide an opportunity to reconstruct the spatial expression of the Eocene hydrologic cycle and its linkage to lake level. Here Sr isotope data from the Wilkins Peak Member, a rhythmic succession that has been demonstrated to record Milankovitch forcing of lake levels, indicate that high lake levels reflect an increased proportion of runoff from less radiogenic rocks west of the basin, eliminating a number of the existing astronomical-forcing hypotheses. The 87Sr/86Sr variability is consistent with a change in mean ENSO state, which is predicted by climate models to be linked to orbital-insolation. Thus, the 87Sr/86Sr data reveal a coupling of high frequency (ENSO) and low frequency (astronomical) climate variability, and also predict the existence of sizable astronomically-forced alpine snowpack during the last greenhouse climate. More broadly, this study demonstrates the utility of 87Sr/86Sr as a powerful tool for reconstructing the deep-time hydrologic cycle.

  18. Solar Thermochemical Energy Storage Through Carbonation Cycles of SrCO3/SrO Supported on SrZrO3.

    Science.gov (United States)

    Rhodes, Nathan R; Barde, Amey; Randhir, Kelvin; Li, Like; Hahn, David W; Mei, Renwei; Klausner, James F; AuYeung, Nick

    2015-11-01

    Solar thermochemical energy storage has enormous potential for enabling cost-effective concentrated solar power (CSP). A thermochemical storage system based on a SrO/SrCO3 carbonation cycle offers the ability to store and release high temperature (≈1200 °C) heat. The energy density of SrCO3/SrO systems supported by zirconia-based sintering inhibitors was investigated for 15 cycles of exothermic carbonation at 1150 °C followed by decomposition at 1235 °C. A sample with 40 wt % of SrO supported by yttria-stabilized zirconia (YSZ) shows good energy storage stability at 1450 MJ m(-3) over fifteen cycles at the same cycling temperatures. After further testing over 45 cycles, a decrease in energy storage capacity to 1260 MJ m(-3) is observed during the final cycle. The decrease is due to slowing carbonation kinetics, and the original value of energy density may be obtained by lengthening the carbonation steps. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. The Crystal Structure of SrCrO4

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    1996-01-01

    X-ray diffraction diagrams taken with Cu-K(alpha) radiation in a Bragg-Brentano diffractometer have shown that the La0.8Sr0.2CrO3 powders, synthesized by drip/spray pyrolysis in a rotating tube furnace at 600-700 oC, contained SrCrO4, in addition to the ceramic perovskite phase. By means...

  20. Single gap superconductivity in doped SrTiO3

    OpenAIRE

    Thiemann, Markus; Beutel, Manfred H.; Dressel, Martin; Lee-Hone, Nicholas R.; Broun, David M.; Fillis-Tsirakis, Evangelos; Boschker, Hans; Mannhart, Jochen; Scheffler, Marc

    2017-01-01

    Doped SrTiO$_3$ is a superconducting oxide that features one of the lowest charge carrier densities among all known superconductors. Undoped, semiconducting SrTiO$_3$ exhibits three unoccupied electronic bands, which can be filled successively by doping, making this system an ideal candidate for multiband superconductivity. The increase of charge carrier density is accompanied by the evolution of a superconducting dome in the phase diagram with critical temperature $T_\\mathrm{c}$ of up to 0.4...

  1. Interim process report for the safety assessment SR-Can

    Energy Technology Data Exchange (ETDEWEB)

    Sellin, Patrick (ed.)

    2004-08-01

    This report is a documentation of buffer processes identified as relevant to the long-term safety of a KBS-3 repository. The report is part of the interim reporting of the safety assessment SR-Can, see further the Interim main report. The final SR-Can reporting will support SKB's application to build an Encapsulation plant for spent nuclear fuel and is to be produced in 2006. The purpose of this report is to document the scientific knowledge of the processes to a level required for an adequate treatment in the safety assessment. The documentation is thus from a scientific point of not exhaustive since such a treatment is neither necessary for the purposes of the safety assessment nor possible within the scope of an assessment. The purpose is further to determine the handling of each process in the safety assessment and to demonstrate how uncertainties are taken care of, given the suggested handling. The process documentation in the SR 97 version of the Process report is a starting point for this SR-Can interim version. As further described in the Interim main report, the list of relevant processes has been reviewed and slightly extended by comparison to other databases. Furthermore, the backfill has been included as a system part of its own, rather than being described together with the buffer as in SR 97. Apart from giving an interim account of the documentation and handling of buffer processes in SR-Can, this report is meant to serve as a template for the forthcoming documentation of processes occurring in other parts of the repository system. A complete list of processes can be found in the Interim FEP report for the safety assessment SR-Can. All material presented in this document is preliminary in nature and will possibly be updated as the SR-Can project progresses.

  2. Cs-137 and Sr-90 level in diary products

    Energy Technology Data Exchange (ETDEWEB)

    Petukhov, V.L.; Dukhanov, Y.A.; Sevryuk, I.Z.; Patrashkov, S.A.; Korotkevich, O.S. [State Agrarian University, Research Institute of Veterinary Genetics and Animal Breeding of Novosibirsk (Russian Federation); Gorb, T.S.; Petukhov, I.V. [Vitebsk State Academy of Veterinary Medicine, Balarus (Russian Federation)

    2003-05-01

    About 70% of radioactive substances fell on the territory of the Byelorussian Republic after the Chernobyl Atom Power Station Disaster. Cs-137 and Sr-90 accumulation dynamics was studied in milk of the cows from the highest polluted Braginsky area. 408 milk samples of Black and White cows were investigated. In 1995 average Cs-137 and Sr-90 levels were 61.00 and 3.73 Bk/dm{sup 3} respectively. Cs-137 and Sr-90 levels exceeded Byelorussian Republic upper limits RDU - 96 in 10 and 50% of milk samples respectively. After 5 years (by 2000) Cs-137 and Sr-90 levels had become almost 3 and 2 times less (21.70 Bk/dm{sup 3} and 1.72 Bk/dm{sup 3} respectively). Cs-137 and Sr-90 levels exceeded RDU - 96 in 1.5 and 5.5% of milk samples respectively. In the same periods Cs-137 and Sr-90 levels were 7 and 2 times higher than the similar indexes in the relatively clean Novosibirsk area. Thus, radioactive element levels in milk of Black and White cows of the Byelorussian Republic decreased significantly for the past years. (authors)

  3. FEP report for the safety assessment SR-Can

    Energy Technology Data Exchange (ETDEWEB)

    Skagius, Kristina [Kemakta Konsult AB, Stockholm (Sweden)

    2006-11-15

    This report documents the analysis and processing of features, events and processes, FEPs, that has been carried out within the safety assessment SR-Can, and forms an important part of the reporting of the project. The SR-Can project is a preparatory stage for the SR-Site assessment, and the report from that project will be used in support of SKB's application to build a final repository. The overall objective of the FEP analysis and processing included development of a database of features, events and processes, an SKB FEP database, in a format that facilitates both a systematic analysis of FEPs and documentation of that FEP analysis, as well as facilitating revisions and updates to be made in connection with new safety assessments. The overall objective also extended to the development of procedures for such a systematic FEP analysis as well as the application of those procedures in order to establish an SR-Can FEP catalogue within the framework of the SKB FEP database. The work started by implementing the content of the SR 97 Process Report into a database format suitable for import and processing of FEP information from other sources. The SR 97 version of the database was systematically audited against the NEA database with Project FEPs, version 1.2. In addition, an earlier audit of the SR 97 process report against the interaction matrices developed for a deep repository of the KBS-3 type was revisited and updated. Relevant FEPs identified through the audit process were sorted into three main categories i) FEPs related to the initial states of the repository system, ii) FEPs related to internal processes of the repository system, and iii) FEPs related to external impacts on the repository system. This resulted in additions to the SR 97 list of processes and to the lists of initial state FEPs and external factors to be addressed in further processing. The further processing of the initial state FEPs revealed that those FEPs that are not covered by the

  4. Direct Observation of Sr Vacancies in SrTiO_{3} by Quantitative Scanning Transmission Electron Microscopy

    Directory of Open Access Journals (Sweden)

    Honggyu Kim

    2016-12-01

    Full Text Available Unveiling the identity, spatial configuration, and microscopic structure of point defects is one of the key challenges in materials science. Here, we demonstrate that quantitative scanning transmission electron microscopy (STEM can be used to directly observe Sr vacancies in SrTiO_{3} and to determine the atom column relaxations around them. By combining recent advances in quantitative STEM, including variable-angle, high-angle annular dark-field imaging and rigid registration methods, with frozen phonon multislice image simulations, we identify which Sr columns contain vacancies and quantify the number of vacancies in them. Picometer precision measurements of the surrounding atom column positions show that the nearest-neighbor Ti atoms are displaced away from the Sr vacancies. The results open up a new methodology for studying the microscopic mechanisms by which point defects control materials properties.

  5. Shape coexistence in neutron-rich Sr isotopes : Coulomb excitation of $^{96}$Sr

    CERN Multimedia

    Clement, E; Siem, S; Czosnyka, T

    2007-01-01

    The nuclei in the mass region A $\\cong$ 100 around Sr and Zr show a dramatic change of the nuclear ground-state shape from near spherical for N $\\leq$ 58 to strongly deformed for N $\\geq$ 60. Theoretical calculations predict the coexistence of slightly oblate and strongly prolate deformed configurations in the transitional region. However, excited rotational structures based on the highly deformed configuration, which becomes the ground state at N = 60, are not firmly established in the lighter isotopes, and the earlier interpretation of a very abrupt change of shape has been challenged by recent experimental results in favor of a rather gradual change. We propose to study the electromagnetic properties of the neutron-rich nucleus $_{38}^{96}$Sr$_{58}$ by low-energy Coulomb excitation using the REX-ISOLDE facility and the MINIBALL detector array. Both transitional and diagonal matrix elements will be extracted, resulting in a complete description of the transition strengths and quadrupole moments of the low-l...

  6. Observation of Isotope Ratios (δ2H, δ18O, 87Sr/86Sr) of Tap Water in Urban Environments

    Science.gov (United States)

    Mancuso, C. J.; Tipple, B. J.; Ehleringer, J. R.

    2014-12-01

    Urban environments are centers for rapidly growing populations. In order to meet the culinary water needs of these areas, municipal water departments use water from multiple locations and/or sources, often piped differentially to different locations within a municipality. This practice creates isotopically distinct locations within an urban area and therefore provides insight to urban water management practices. In our study we selected urban locations in the Salt Lake Valley, UT (SLV) and San Francisco Bay Area, CA (SFB) where we hypothesized geographically distinct water isotopic ratio differences existed. Within the SLV, municipal waters come from the same mountainous region, but are derived from different geologically distinct watersheds. In contrast, SFB waters are derived from regionally distinct water sources. We hypothesized that the isotope ratios of tap waters would differ based upon known municipal sources. To test this, tap water samples were collected throughout the urban regions in SLV and SFB and analyzed for δ2H, δ18O and 87Sr/86Sr isotope ratios. Seasonal collections were also made to assess if isotope ratios differed throughout the year. Within SLV and SFB, different regions were characterized by distinct paired δ18O and 87Sr/86Sr values. These different realms also agreed with known differences in municipal water supplies within the general geographic region. Waters from different cities within Marin County showed isotopic differences, consistent with water derived from different local reservoirs. Seasonal variation was observed in paired δ18O and 87Sr/86Sr values of tap water for some locations within SLV and SFB, indicating management decisions to shift from one water source to another depending on demand and available resources. Our study revealed that the δ18O and 87Sr/86Sr values of tap waters in an urban region can exhibit significant differences despite close spatial proximity if districts differ in their use of local versus

  7. Stellar laboratories . IX. New Se v, Sr iv-vii, Te vi, and I vi oscillator strengths and the Se, Sr, Te, and I abundances in the hot white dwarfs G191-B2B and RE 0503-289

    Science.gov (United States)

    Rauch, T.; Quinet, P.; Knörzer, M.; Hoyer, D.; Werner, K.; Kruk, J. W.; Demleitner, M.

    2017-10-01

    Context. To analyze spectra of hot stars, advanced non-local thermodynamic equilibrium (NLTE) model-atmosphere techniques are mandatory. Reliable atomic data is crucial for the calculation of such model atmospheres. Aims: We aim to calculate new Sr iv-vii oscillator strengths to identify for the first time Sr spectral lines in hot white dwarf (WD) stars and to determine the photospheric Sr abundances. To measure the abundances of Se, Te, and I in hot WDs, we aim to compute new Se v, Te vi, and I vi oscillator strengths. Methods: To consider radiative and collisional bound-bound transitions of Se v, Sr iv - vii, Te vi, and I vi in our NLTE atmosphere models, we calculated oscillator strengths for these ions. Results: We newly identified four Se v, 23 Sr v, 1 Te vi, and three I vi lines in the ultraviolet (UV) spectrum of RE 0503-289. We measured a photospheric Sr abundance of 6.5+ 3.8-2.4× 10-4 (mass fraction, 9500-23 800 times solar). We determined the abundances of Se (1.6+ 0.9-0.6× 10-3, 8000-20 000), Te (2.5+ 1.5-0.9× 10-4, 11 000-28 000), and I (1.4+ 0.8-0.5× 10-5, 2700-6700). No Se, Sr, Te, and I line was found in the UV spectra of G191-B2B and we could determine only upper abundance limits of approximately 100 times solar. Conclusions: All identified Se v, Sr v, Te vi, and I vi lines in the UV spectrum of RE 0503-289 were simultaneously well reproduced with our newly calculated oscillator strengths. Based on observations with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26666. Based on observations made with the NASA-CNES-CSA Far Ultraviolet Spectroscopic Explorer. Full Tables A.15 to A.21 are only available via the German Astrophysical Virtual Observatory (GAVO) service TOSS (http://dc.g-vo.org/TOSS).

  8. Spectroscopic and electric dipole properties of Sr+Ar and SrAr systems including high excited states

    Science.gov (United States)

    Hamdi, Rafika; Abdessalem, Kawther; Dardouri, Riadh; Al-Ghamdi, Attieh A.; Oujia, Brahim; Gadéa, Florent Xavier

    2018-01-01

    The spectroscopic properties of the fundamental and several excited states of Sr+Ar and SrAr, Van der Waals systems are investigated by employing an ab initio method in a pseudo-potential approach. The potential energy curves and the spectroscopic parameters are displayed for the 1–10 2Σ+, 1–6 2Π and 1–3 2Δ electronic states of the Sr+Ar molecule and for the 1–6 1Σ+, 1–4 3Σ+, 1–3 1,3Π and 1–3 1,3Δ states of the neutral molecule SrAr. In addition, from these curves, the vibrational levels and their energy spacing are deduced for Σ+, Π and Δ symmetries. The spectra of the permanent and transition dipole moments are studied for the 1,3Σ+ states of SrAr, which are considered to be two-electron systems and 2Σ+ states of the single electron Sr+Ar ion. The spectroscopic parameters obtained for each molecular system are compared with previous theoretical and experimental works. A significant correlation revealed the accuracy of our results.

  9. Low lattice thermal conductivity suppressed by Sr-deficiency in Sr0.9Ca0.1Si2

    Directory of Open Access Journals (Sweden)

    C. S. Lue

    2013-07-01

    Full Text Available We present a study of the temperature-dependent electrical resistivity, Seebeck coefficient, and thermal conductivity in Sr0.9-δCa0.1Si2 alloys to shed light on Sr-deficient effect on the thermoelectric performance, as characterized by the dimensionless thermoelectric figure-of-merit, ZT. It is found that the thermal conductivity is considerably reduced upon introducing Sr deficiency in Sr0.9Ca0.1Si2. In particular, a marked low lattice thermal conductivity of about 1.1 W/m-K at room temperature is achieved for Sr0.77Ca0.1Si2. Such a promising result leads to a relatively high ZT of 0.27 at room temperature for this material. Furthermore, with the extrapolation of thermoelectric parameters to high temperatures, a possible maximum ZT of about 0.52 at 850 K can be realistically estimated for Sr0.77Ca0.1Si2.

  10. Effect of Flowing Water on Sr Sorption Changes of Hydrous Sodium Titanate

    Directory of Open Access Journals (Sweden)

    Youko Takahatake

    2017-12-01

    Full Text Available Radioactive contaminated water has been generated at the Fukushima Daiichi Nuclear Power station (F1NPS. Hydrous sodium titanate (SrTreat® is able to remove radioactive Strontium (Sr from this water. Knowing the amount of radioactive nuclides in the used as-received SrTreat® is important for effective disposal and deposition of the F1NPS waste. This study investigated changes in the ability of SrTreat® to sorb Sr, and to understand the causes of changes in the sorbing. An investigation of the Sr sorption ability of SrTreat® is important for calculating the initial radioactive inventory of used SrTreat®. This study carries out Sr sorption studies with acid-base titrations and X-ray photoelectron spectroscopy (XPS to characterize the properties. After exposure to simulated treated water for 99 h, the surface structure of the SrTreat® was changed, and the percentage of sorbed Sr and the buffer capacity for protons decreased. When the amount of radioactive nuclides contained in the used SrTreat® is calculated from the sorption data of the as-received SrTreat®, the radioactive Sr content will be overestimated with a concomitant increase in the deposition and disposal costs of the used SrTreat®.

  11. Sr-Isotope record of Quaternary marine terraces on the California coast and off Hawaii

    Science.gov (United States)

    Ludwig, K. R.; Muhs, D.R.; Simmons, K.R.; Moore, J.G.

    1992-01-01

    Strontium-isotopic ratios of dated corals have been obtained from submerged reefs formed during Quaternary glacial periods off the Hawaiian islands. These data, combined with data from deep-sea sediments, tightly constrain the secular variation of marine 87Sr 86Sr for the past 800,000 yr. Although long-term trends are apparent, no significant (>0.02???), rapid (<100,000 yr) excursions in 87Sr 86Sr were resolved nor did we observe any samples with 87Sr 86Sr greater than that of modern seawater. Strontium in mollusks from elevated marine terraces formed during interglacial periods on the southern California coast show resolvable and consistent variations in 87Sr 86Sr which, when compared to the trend of Quaternary marine 87Sr 86Sr, can be used to infer uplift rates and define approximate ages for the higher terraces. The Sr-isotope age estimates indicate that uplift rates vary among crustal blocks and were not necessarily constant with time. No contrast in Sr-isotopic ratios between similar-age Hawaiian and California fossils was observed, confirming that any change in marine 87Sr 86Sr from glacial to interglacial periods must be small. A realistic appraisal of the potential of Sr-isotope stratigraphy for chronometric applications in the Quaternary suggests that the technique will be limited to relatively coarse distinctions in age. ?? 1992.

  12. MODIFIKASI KATALIS CaO DENGAN SrO PADA REAKSI TRANSESTERIFIKASI MINYAK JELANTAH MENJADI BIODIESEL MENGGUNAKAN

    Directory of Open Access Journals (Sweden)

    N Widiarti

    2016-03-01

    public health. In this research, the transesterification reaction of wasted cooking oil into biodiesel by using CaO catalyst modified with SrO. The purpose of this study was to determine characteristics of the catalyst and catalytic activity in the transesterification reaction of wasted cooking oil. Catalyst modification performed by impregnation method of SrNO3 into CaO. The catalyst was used in transesterification reaction of wasted cooking oil with variation of  energy (80 and 100 watt, variation of time (30, 60, 90, 120, and 150 seconds and variation of SrO/CaO amount (1%, 2%, 4%, 8% and 16% w/w as a catalyst. Catalyst characterization performed by XRD and FTIR. The result of XRD showed that the catalyst SrO/CaO are crystalline and have a characteristic diffraction pattern of CaO and SrO combination. Optimal activity of catalyst was at 100 watt  energy, reaction time of 120 seconds and 4% w/w SrO/CaO with the reaction product of methyl ester was 92.86%.

  13. La interstitial defect-induced insulator-metal transition in the oxide heterostructures LaAl O3 /SrTi O3

    Science.gov (United States)

    Zhou, Jun; Yang, Ming; Feng, Yuan Ping; Rusydi, Andrivo

    2017-11-01

    Perovskite oxide interfaces have attracted tremendous research interest for their fundamental physics and promising all-oxide electronic applications. Here, based on first-principles calculations, we propose a surface La interstitial promoted interface insulator-metal transition in LaAl O3 /SrTi O3 (110). Compared with surface oxygen vacancies, which play a determining role on the insulator-metal transition of LaAl O3 /SrTi O3 (001) interfaces, we find that surface La interstitials can be more experimentally realistic and accessible for manipulation and more stable in an ambient atmospheric environment. Interestingly, these surface La interstitials also induce significant spin-splitting states with a Ti dy z/dx z character at a conducting LaAl O3 /SrTi O3 (110) interface. On the other hand, for insulating LaAl O3 /SrTi O3 (110) (<4 unit cells LaAl O3 thickness), a distortion between La (Al) and O atoms is found at the LaAl O3 side, partially compensating the polarization divergence. Our results reveal the origin of the metal-insulator transition in LaAl O3 /SrTi O3 (110) heterostructures, and also shed light on the manipulation of the superior properties of LaAl O3 /SrTi O3 (110) for different possibilities in electronic and magnetic applications.

  14. Synthesis of SrO.SiO2 Catalyst and Its Application in the Transesterification Reactions of Soybean Oil

    Directory of Open Access Journals (Sweden)

    Nuni Widiarti

    2017-05-01

    Full Text Available The synthesis and characterization of SrO.SiO2 were carried out. The rice hull ash was utilized as a source for SiO2. The SrO.SiO2 was prepared by sol-gel technique, and the ratios of SrO:SiO2 were      varied as 0:1, 1:0, 3:2, 2:4, and 2:7. The sol-gel was calcined at 800 oC for 4 hours. The result was    characterized using XRD and FTIR. The diffraction pattern shows that the diffraction angle was shifted, and the intensity of the main peaks was increased. This research indicated that the            crystallinity of SrO was improved at the higher SiO content. Further, a new peak was observed in the IR spectra at a wavenumber of 900 cm-1 indicating the appearance of new functional groups of the SrO.SiO2. The catalytic activity of SrO.SiO2 on transesterification reaction was optimized. The optimum condition was obtained at SrO.SiO2 of 2:7, reaction time of 30 minutes, reaction temperature of 65 oC, the amount of catalyst of 1 % w/v of reactants, and the biodiesel yield of 96.66 %. Copyright © 2017 BCREC Group. All rights reserved Received: 11st November 2016; Revised: 28th February 2017; Accepted: 28th February 2017 How to Cite: Widiarti, N., Suryana, L.A., Wijayati, N., Rahayu, E.F., Harjito, H., Wardhana, S.B., Prasetyoko, D., Suprapto, S. (2017. Synthesis of SrO.SiO2 Catalyst and Its Application in the Transesterification Reactions of Soybean Oil. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (2: 299-305 (doi:10.9767/bcrec.12.2.804.299-305 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.12.2.804.299-305

  15. [Research progress of effects of strontium ranelate on osteoarthritis].

    Science.gov (United States)

    Wang, Yu; Dai, Muwei; Tian, Faming; Zhang, Liu

    2014-12-01

    To review the research progress focused on the effects of strontium ranelate (SR) on osteoarthritis. The relevant literature about the effects and mechanism of SR intervening osteoarthritis in recent years was extensively reviewed and comprehensively analyzed. SR not only could improve the microenvironment of bone metabolism in articular cartilage with osteoarthritis, promote activity of osteoblasts, and inhibit activity of osteoclasts, but also could adjust the expression of key proteases which affect cartilage formation, and therefore it has a potential protective effect on subchondral bone during the progression of osteoarthritis cartilage. SR is expected to become a drug of osteoarthritis disease remission, but further studies are needed to clarify the mechanism of SR in osteoarthritis, and finally confirm the best application dosage of SR in osteoarthritis treatment.

  16. Research Research

    African Journals Online (AJOL)

    Research. May 2014, Vol. 6, No. 1 AJHPE 33. Research. Currently, radiography students are faced with the challenge of having to learn factual information, while ... A descriptive exploratory research design was used to collect both ..... Creswell J. Research Design: Quantitative, Qualitative and Mixed Methods Approaches.

  17. Sr36- and Sr5-Mediated Resistance Response to Puccinia graminis f. sp. tritici Is Associated with Callose Deposition in Wheat Guard Cells.

    Science.gov (United States)

    Wang, X; McCallum, B D; Fetch, T; Bakkeren, G; Saville, B J

    2015-06-01

    Race-specific resistance of wheat to Puccinia graminis f. sp. tritici is primarily posthaustorial and often involves the induction of a hypersensitive response (HR). The aim of this study was to investigate host defense responses induced in interactions between P. graminis f. sp. tritici races and wheat lines carrying different race-specific stem rust resistance (Sr) genes. In incompatible interactions between wheat lines carrying Sr36 in three genetic backgrounds (LMPG, Prelude, or W2691) and avirulent P. graminis f. sp. tritici races MCCFC or RCCDM, callose accumulated within 24 h in wheat guard cells contacted by a P. graminis f. sp. tritici appressorium, and P. graminis f. sp. tritici ingress was inhibited following appressorium formation. Accordingly, the expression of transcripts encoding a callose synthase increased in the incompatible interaction between LMPG-Sr36 and avirulent P. graminis f. sp. tritici race MCCFC. Furthermore, the inhibition of callose synthesis through the infiltration of 2-deoxy-D-glucose (DDG) increased the ability of P. graminis f. sp. tritici race MCCFC to infect LMPG-Sr36. A similar induction of callose deposition in wheat guard cells was also observed within 24 h after inoculation (hai) with avirulent P. graminis f. sp. tritici race HKCJC on LMPG-Sr5 plants. In contrast, this defense response was not induced in incompatible interactions involving Sr6, Sr24, or Sr30. Instead, the induction of an HR and cellular lignification were noted. The manifestation of the HR and cellular lignification was induced earlier (24 hai) and was more extensive in the resistance response mediated by Sr6 compared with those mediated by Sr24 or Sr30. These results indicate that the resistance mediated by Sr36 is similar to that mediated by Sr5 but different from those triggered by Sr6, Sr24, or Sr30. Resistance responses mediated by Sr5 and Sr36 are prehaustorial, and are a result of very rapid recognition of molecules derived from avirulent isolates of

  18. 90Sr and 89Sr in seawater off Japan as a consequence of the Fukushima Dai-ichi nuclear accident

    Directory of Open Access Journals (Sweden)

    N. Casacuberta

    2013-06-01

    Full Text Available The impact of the earthquake and tsunami on the east coast of Japan on 11 March 2011 caused a loss of power at the Fukushima Dai-ichi nuclear power plant (NPP that resulted in one of the most important releases of artificial radioactivity into the environment. Although several works were devoted to evaluating the atmospheric dispersion of radionuclides, the impact of the discharges to the ocean has been less investigated. Here we evaluate the distribution of Fukushima-derived 90Sr (n = 57 and 89Sr (n = 19 throughout waters 30–600 km offshore in June 2011. Concentrations of 90Sr and 89Sr in both surface waters and shallow profiles ranged from 0.8 ± 0.2 to 85 ± 3 Bq m−3 and from 19 ± 6 to 265 ± 74 Bq m−3, respectively. Because of its short half-life, all measured 89Sr was due to the accident, while the 90Sr concentrations can be compared to the background levels in the Pacific Ocean of about 1.2 Bq m−3. Fukushima-derived radiostrontium was mainly detected north of Kuroshio Current, as this was acting as a southern boundary for transport. The highest activities were associated with near-shore eddies, and larger inventories were found in the closest stations to Fukushima NPP. The data evidence a major influence of direct liquid discharges of radiostrontium compared to the atmospheric deposition. Existing 137Cs data reported from the same samples allowed us to establish a 90Sr / 137Cs ratio of 0.0256 ± 0.0006 in seawater off Fukushima, being significantly different than that of the global atmospheric fallout (i.e., 0.63 and may be used in future studies to track waters coming from the east coast of Japan. Liquid discharges of 90Sr to the ocean were estimated, resulting in an inventory of 53 ± 1 TBq of 90Sr in the inshore study area in June 2011 and total releases of 90Sr ranging from 90 to 900 TBq, depending upon the reported estimates of 137Cs releases that are considered.

  19. 90Sr and 89Sr in seawater off Japan as a consequence of the Fukushima Dai-ichi nuclear accident

    Science.gov (United States)

    Casacuberta, N.; Masqué, P.; Garcia-Orellana, J.; Garcia-Tenorio, R.; Buesseler, K. O.

    2013-06-01

    The impact of the earthquake and tsunami on the east coast of Japan on 11 March 2011 caused a loss of power at the Fukushima Dai-ichi nuclear power plant (NPP) that resulted in one of the most important releases of artificial radioactivity into the environment. Although several works were devoted to evaluating the atmospheric dispersion of radionuclides, the impact of the discharges to the ocean has been less investigated. Here we evaluate the distribution of Fukushima-derived 90Sr (n = 57) and 89Sr (n = 19) throughout waters 30-600 km offshore in June 2011. Concentrations of 90Sr and 89Sr in both surface waters and shallow profiles ranged from 0.8 ± 0.2 to 85 ± 3 Bq m-3 and from 19 ± 6 to 265 ± 74 Bq m-3, respectively. Because of its short half-life, all measured 89Sr was due to the accident, while the 90Sr concentrations can be compared to the background levels in the Pacific Ocean of about 1.2 Bq m-3. Fukushima-derived radiostrontium was mainly detected north of Kuroshio Current, as this was acting as a southern boundary for transport. The highest activities were associated with near-shore eddies, and larger inventories were found in the closest stations to Fukushima NPP. The data evidence a major influence of direct liquid discharges of radiostrontium compared to the atmospheric deposition. Existing 137Cs data reported from the same samples allowed us to establish a 90Sr / 137Cs ratio of 0.0256 ± 0.0006 in seawater off Fukushima, being significantly different than that of the global atmospheric fallout (i.e., 0.63) and may be used in future studies to track waters coming from the east coast of Japan. Liquid discharges of 90Sr to the ocean were estimated, resulting in an inventory of 53 ± 1 TBq of 90Sr in the inshore study area in June 2011 and total releases of 90Sr ranging from 90 to 900 TBq, depending upon the reported estimates of 137Cs releases that are considered.

  20. SR 97. Processes in the repository evolution. Background report to SR 97

    Energy Technology Data Exchange (ETDEWEB)

    Hedin, A. [ed.

    1999-11-01

    This report describes, in a comprehensive and coherent fashion, all identified internal processes of importance for the post-closure evolution and safety of a KBS-3 repository for spent nuclear fuel. The report has been written to be used in the SR 97 project, which has limited the time available for its preparation. Differences in the level of detail in descriptions of different processes do not always reflect differences in the significance of the processes. Discussions of different types of uncertainties could in many cases be broadened and deepened, and the stylistic quality could sometimes be improved. Like other background material for the safety assessments, the process report is also expected to require revision as site-specific conditions are progressively clarified. Today's version of the process report is therefore the firstversion of a report that will be revised prior to every safety report. The intention is to perform the first revision of the report after scrutiny of SR 97. The report describes the internal processes which over time lead to changes in a KBS-3 repository for spent nuclear fuel. The context of the material in the report is described in SR 97 Main Report and briefly entails the following: The repository has been divided into four subsystems: fuel/cavity, cast iron insert/copper canister, buffer/backfill and geosphere. A number of processes of importance for the post-closure evolution of the repository have been identified within each subsystem. This has been done with the aid of material in the so-called interaction matrices previously developed by SKB. The processes have been divided into the categories thermal, hydraulic, mechanical and chemical. Furthermore, there are processes related to radiation and radionuclide transport. The identified processes are documented in this report. Each subsystem has its own chapter, and each chapter is divided into radiation related, thermal, hydraulic, mechanical and chemical processes as well

  1. Isotopic reconstruction of ancient human migrations: A comprehensive Sr isotope reference database for France and the first case study at Tumulus de Sables, south-western France

    Science.gov (United States)

    Willmes, M.; Boel, C.; Grün, R.; Armstrong, R.; Chancerel, A.; Maureille, B.; Courtaud, P.

    2012-04-01

    Strontium isotope ratios (87Sr/86Sr) can be used for the reconstruction of human and animal migrations across geologically different terrains. Sr isotope ratios in rocks are a product of age and composition and thus vary between geologic units. From the eroding environment Sr is transported into the soils, plants and rivers of a region. Humans and animals incorporate Sr from their diet into their bones and teeth, where it substitutes for calcium. Tooth enamel contains Sr isotope signatures acquired during childhood and is most resistant to weathering and overprinting, while the dentine is often diagenetically altered towards the local Sr signature. For the reconstruction of human and animal migrations the tooth enamel 87Sr/86Sr ratio is compared to the Sr isotope signature in the vicinity of the burial site and the surrounding area. This study focuses on the establishment of a comprehensive reference map of bioavailable 87Sr/86Sr ratios for France. In a next step we will compare human and animal teeth from key archaeological sites to this reference map to investigate mobility. So far, we have analysed plant and soil samples from ~200 locations across France including the Aquitaine basin, the western and northern parts of the Paris basin, as well as three transects through the Pyrenees Mountains. The isotope data, geologic background information (BRGM 1:1M), field images, and detailed method descriptions are available through our online database iRhum (http://rses.anu.edu.au/research/ee). This database can also be used in forensic studies and food sciences. As an archaeological case study teeth from 16 adult and 8 juvenile individuals were investigated from an early Bell Beaker (2500-2000 BC) site at Le Tumulus des Sables, south-west France (Gironde). The teeth were analysed for Sr isotope ratios using laser ablation ICP-MS. Four teeth were also analysed using solution ICP-MS, which showed a significant offset to the laser ablation results. This requires further

  2. Molecular detection of 16SrI-B and 16SrII-D subgroups of phytoplasma associated with flat stem and witches' broom disease of Celosia argentea L.

    Science.gov (United States)

    Madhupriya; Yadav, Amit; Thorat, Vipool; Rao, G P

    2017-10-01

    Symptoms of stunting (shortening of internodes), twisting and flat stem (the fasciation of a stem), discoloration of petals, deformed flowers, and witches' broom were recorded on an ornamental plant, plumed cockscomb (Celosia argentea L., fam: Amaranthaceae). The survey conducted at Indian Agricultural Research Institute (IARI) campus, New Delhi and Karnal region, Haryana, India, during September 2014 to March 2015 revealed disease incidence of 40 and 10%, respectively. The 16S rRNA gene sequence comparison and phylogenetic relationships of Celosia phytoplasma strains under study confirmed that they were associated with two different phytoplasma groups ('Candidatus Phytoplasma australasia' and 'Ca. P. asteris'). Virtual RFLP analysis of 16S rRNA gene sequences allowed further classification of the Celosia phytoplasma strains into the 16SrI-B and 16SrII-D subgroups. Notably, the detection of 'Ca. P. asteris' phytoplasma was reported in seeds of C. argentea by nested PCR assays; however, no evidence of phytoplasma presence was detected in seedlings raised from these seeds. This observation is the first record of the association of 16SrI-B and 16SrII-D subgroups of phytoplasmas with flat stem and witches' broom disease of C. argentea anywhere from the world.

  3. High-precision 87Sr/86Sr analyses in wines and their use as a geological fingerprint for tracing geographic provenance.

    Science.gov (United States)

    Marchionni, Sara; Braschi, Eleonora; Tommasini, Simone; Bollati, Andrea; Cifelli, Francesca; Mulinacci, Nadia; Mattei, Massimo; Conticelli, Sandro

    2013-07-17

    The radiogenic isotopic compositions of inorganic heavy elements such as Sr, Nd, and Pb of the food chain may constitute a reliable geographic fingerprint, their isotopic ratios being inherited by the geological substratum of the territory of production. The Sr isotope composition of geomaterials (i.e., rocks and soils) is largely variable, and it depends upon the age of the rocks and their nature (e.g., genesis, composition). In this study we developed a high-precision analytical procedure for determining Sr isotopes in wines at comparable uncertainty levels of geological data. With the aim of verifying the possibility of using Sr isotope in wine as a reliable tracer for geographic provenance, we performed Sr isotope analyses of 45 bottled wines from four different geographical localities of the Italian peninsula. Their Sr isotope composition has been compared with that of rocks from the substrata (i.e., rocks) of their vineyards. In addition wines from the same winemaker but different vintage years have been analyzed to verify the constancy with time of the (87)Sr/(86)Sr. Sr isotope compositions have been determined by solid source thermal ionization mass spectrometry following purification of Sr in a clean laboratory. (87)Sr/(86)Sr of the analyzed wines is correlated with the isotopic values of the geological substratum of the vineyards, showing little or no variation within the same vineyard and among different vintages. Large (87)Sr/(86)Sr variation is observed among wines from the different geographical areas, reinforcing the link with the geological substratum of the production territory. This makes Sr isotopes a robust geochemical tool for tracing the geographic authenticity and provenance of wine.

  4. SR-targeted CaMKII inhibition improves SR Ca2+ handling, but accelerates cardiac remodeling in mice overexpressing CaMKIIδC

    Science.gov (United States)

    Huke, Sabine; DeSantiago, Jaime; Kaetzel, Marcia A.; Mishra, Shikha; Brown, Joan H.; Dedman, John R.; Bers, Donald M.

    2010-01-01

    Cardiac myocyte overexpression of CaMKIIδC leads to cardiac hypertrophy and heart failure (HF) possibly caused by altered myocyte Ca2+ handling. A central defect might be the marked CaMKII-induced increase in diastolic sarcoplasmic reticulum (SR) Ca2+ leak which decreases SR Ca2+ load and Ca2+ transient amplitude. We hypothesized that inhibition of CaMKII near the SR membrane would decrease the leak, improve Ca2+ handling and prevent the development of contractile dysfunction and HF. To test this hypothesis we crossbred CaMKIIδC overexpressing mice (CaMK) with mice expressing the CaMKII-inhibitor AIP targeted to the SR via a modified phospholamban (PLB)-transmembrane-domain (SR-AIP). There was a selective decrease in the amount of activated CaMKII in the microsomal (SR/membrane) fraction prepared from these double-transgenic mice (CaMK/SR-AIP) mice. In ventricular cardiomyocytes from CaMK/SR-AIP mice, SR Ca2+ leak, assessed both as diastolic Ca2+ shift into SR upon tetracaine in intact myocytes or integrated Ca2+ spark release in permeabilized myocytes, was significantly reduced. The reduced leak was accompanied by enhanced SR Ca2+ load and twitch amplitude in double-transgenic mice (vs. CaMK), without changes in SERCA expression or NCX function. However, despite the improved myocyte Ca2+ handling, cardiac hypertrophy and remodeling was accelerated in CaMK/SR-AIP and cardiac function worsened. We conclude that while inhibition of SR localized CaMKII in CaMK mice improves Ca2+ handling, it does not necessarily rescue the HF phenotype. This implies that a non-SR CaMKIIδC exerts SR-independent effects that contribute to hypertrophy and HF, and this CaMKII pathway may be exacerbated by the global enhancement of Ca transients. PMID:20971119

  5. Communication Research: New Challenges of the Latin American School.

    Science.gov (United States)

    Marques de Melo, Jose

    1993-01-01

    Offers a review of Latin American scholarly research on communication processes from the 1940s to the early 1990s. Notes international interest in this research and the new challenges faced by it. (SR)

  6. Preparation and characterization of Sr-Ti-hardystonite (Sr-Ti-HT nanocomposite for bone repair application

    Directory of Open Access Journals (Sweden)

    Hossein Mohammadi

    2015-07-01

    Full Text Available Objective(s: Hardystonite (HT is Zn-modified silicate bioceramics with promising results for bone tissue regeneration. However, HT possesses no obvious apatite formation. Thus, in this study we incorporated Sr and Ti into HT to prepare Sr-Ti-hardystonite (Sr-Ti-HT nanocomposite and evaluated its in vitro bioactivity with the purpose of developing a more bioactive bone substitute material. Materials and methods:The HT and Sr-Ti-HT were prepared by mechanical milling and subsequent heat treatment. Calcium oxide (CaO, zinc oxide (ZnO and silicon dioxide (SiO2 (all from Merck were mixed with molar ratio of 2:1:2. The mixture of powders mixture was then milled in a planetary ball mill for 20 h. In the milling run, the ball-to-powder weight ratio was 10:1 and the rotational speed was 200 rpm. After synthesis of HT, 3% nanotitanium dioxide (TiO2, Degussa and 3% strontium carbonate (SrCO3, Merck were added to HT and then the mixture was ball milled and calcined at 1150°C for 6 h. Simultaneous thermal analysis (STA, X-ray diffraction (XRD, Transmission electron microscopy (TEM and Fourier transform infra-red spectroscopy (FT-IR performed to characterize the powders. Results:XRD and FT-IR confirmed the crystal phase and silicate structure of HT and TEM images demonstrated the nanostructure of powders. Further, Sr-Ti-HT induced apatite formation and showed a higher human mesenchymal stem cell (hMSCs adhesion and proliferation compared to HT. Conclusion:Our study revealed that Sr-Ti-HT with a nanostructured crystal structure of 50 nm, can be prepared by mechanical activation to use as biomaterials for orthopedic applications.

  7. DX16 is a novel SR protein phosphorylated by DOA.

    Science.gov (United States)

    Wan, Yongqi; Sun, Mingkuan; Wang, Shanzhi; Liu, Li; Yuan, Liudi; Xie, Wei

    2008-01-01

    The serine-arginine-rich (SR) proteins belong to a conserved splicing factor family that not only is essential for constitutive pre-mRNA splicing, but also plays important roles in regulation of alternative splicing. Dx16 is a member of SR protein family in Drosophila. In order to get more insight of dx16 function, we identified the proteins interacting with DX16 through yeast two-hybrid and GST-pull down assays. DX16 interacts with the U1 snRNP subunit CG7564, the SR protein RBP1 and the SR protein kinase DOA. The first and second serine-and arginine-rich regions of DOA are required for the interaction between DOA and DX16. DX16 could be phosphorylated by DOA in vitro and DX16 is highly phosphorylated in vivo. Immunofluorescence microscopy results reveal that doa and dx16 are both highly expressed in embryonic central nervous system. These results suggest that DX16 could be a novel SR protein phosphorylated by DOA and it may participate in the formation of splicing complex through its interactions with other splicing related proteins.

  8. Interim data report for the safety assessment SR-Can

    Energy Technology Data Exchange (ETDEWEB)

    Vahlund, Fredrik [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Andersson, Johan [JA Streamflow AB, Aelvsjoe (Sweden)

    2004-08-01

    This document is the interim data report in the project SR-Can. The purpose of the data report is to present input data, with uncertainty estimates, for the SR-Can assessment calculations. Besides input data, the report also describes the standardised procedures used when deriving the input data and the corresponding uncertainty estimates. However, in the present interim version of the report (written in the initial stage of the project when site characterisation has yet not been completed) the standardised procedures have not been possible to apply for most of the data and, in order to present a compilation of the data used in the assessment, much of the input data is presented without following the standardised procedures. This will however be changed for the final version of the SR-Can data report, in order to show the methodology that will be used in the final version one example of how input data will be presented is included (migration data for buffer) . The recommended input data for the assessment calculations are, for the interim version, mainly based on SR 97 Beberg data, these are merely presented without any background or uncertainty discussion (this is presented in the SR 97 data report)

  9. Sr ISOTOPES AND ROMAGNA WINES: AN OPPORTUNITY FOR BETTER TRADING?

    Directory of Open Access Journals (Sweden)

    Umberto Masi

    2011-12-01

    Full Text Available The Sr isotopic compositions of 11 wines from Romagna were determined with the aim of providing a new parameter to track the origin of these wines and serving for better trading. The 87Sr values measured ranged narrowly from -0.07 to +0.33 permil, in agreement with the provenance of the parent grapes from an area characterized by substantial uniformity of soil composition. However, so far, it is possible to make a preliminary distinction of the Sangiovese wines from the other wines analyzed because the former contain slightly more radiogenic Sr. This may reflect the different soil geology of vineyards, as the Sangiovese wines are made from grapes mainly growing on flysch soils, while the other wines are from grapes growing on sedimentary and alluvial Pliocene-Quaternary soils. The comparison of the data from Romagna wines with those of other Italian regions shows the potential of the 87Sr to characterize most of these products. However, the data are ambiguous for distinguishing the wines from vinyards growing on similar lithologies, i.e. soils developed on Late Cenozoic sedimentary rocks. The application of Sr isotopes may be a promising tool for setting the fingerprints of wines when combined with other isotopic and chemical parameters.

  10. Andreev reflection and spin polarization of SrRuO{sub 3} thin films on SrTiO{sub 3} (111)

    Energy Technology Data Exchange (ETDEWEB)

    Foerster, M; Rigato, F; Fontcuberta, J [Institut de Ciencia de Materials de Barcelona - CSIC, E-08193 Bellaterra (Spain); Piano, S; Mellor, C J, E-mail: mfoerster@icmab.es [School of Physics and Astronomy, University of Nottingham, NG7 2RD Nottingham (United Kingdom)

    2011-07-06

    Epitaxial SrRuO{sub 3} thin films with an extremely flat surface morphology suitable for the use in thin film heterostructures have been grown on SrTiO{sub 3} (111) substrates. The transport spin polarization was measured by point contact spectroscopy for SrRuO{sub 3} films on SrTiO{sub 3} (111) and comparable samples on SrTiO{sub 3} (001). The measured polarization for both types of samples is slightly smaller than previously measured by the same technique. Possible reasons for this difference are discussed.

  11. Biodistribution of [{sup 18}f] SR144385 and [{sup 18}f] SR147963: selective radioligands for positron emission tomographic studies of brain cannabinoid receptors

    Energy Technology Data Exchange (ETDEWEB)

    Mathews, William B. E-mail: bmathews@petscan.nm.jhu.edu; Scheffel, Ursula; Finley, Paige; Ravert, Hayden T.; Frank, Richard A.; Rinaldi-Carmona, Murielle; Barth, Francis; Dannals, Robert F

    2000-11-01

    [{sup 18}F] SR144385 and [{sup 18}F] SR147963 were synthesized in a multistep reaction in which fluorine-18 was introduced by nucleophilic halogen displacement on a bromo precursor. The fluorine-18-labeled intermediate was deprotected and coupled with the appropriate alkyl amine to give the final products. Both radioligands had appropriate regional brain distribution for cannabinoid receptors with a target to nontarget ratio of 1.7 for [{sup 18}F] SR147963 and 2.5 for [{sup 18}F] SR144385 at 60 and 90 min postinjection, respectively. The uptake of both tracers was blocked with a 1 mg/kg dose of SR141716A.

  12. Preparación y caracterización de óxidos de cobalto Cuasi-bidimensionales Ln1-xSr1+xCoO4 (Ln= La, Nd y Gd

    Directory of Open Access Journals (Sweden)

    Señarís-Rodríguez, M. A.

    2004-08-01

    Full Text Available By using the nitrate decomposition method in the presence of KNO3, we have been able to enlarge the compositional range of the cobaltlayered compounds Ln1-xSr1+xCoO4 (Ln: La, Nd, Gd to 0≤x≤0.40 in the case of lanthanum, to 0≤x≤0.30 for neodymium, and to 0≤x≤0.20 in the case of gadolinium. In this work we present the results of their structural characterization by means of powder X-ray diffraction (PXD and Rietveld analysis as a function of composition (x and the rare earth (Ln, information that has been complemented by infrared spectroscopy (IR, electron diffraction (ED and electron microscopy.Mediante el método de descomposición de nitratos en presencia de KNO3, se ha conseguido aumentar el rango composicional de los compuestos cuasi-bidimensionales de cobalto Ln1-xSr1+xCoO4 (Ln: La, Nd y Gd, a 0≤x≤0.4 cuando Ln = La, 0≤x≤0.3 cuando Ln = Nd y 0≤x≤0.2 cuando Ln = Gd. En este trabajo se presentan los resultados de su caracterización estructural mediante difracción de rayos X en polvo (DRX y análisis Rietveld tanto en función de la composición (x como de la tierra rara (Ln, información que se complementa con datos de espectroscopía de infrarrojo (IR, difracción de electrones (DE y microscopía electrónica (ME.

  13. A unified mechanism for 2DEG at SrTiO3 /LaAlO3 interface

    Science.gov (United States)

    Yu, Liping; Zunger, Alex

    2014-03-01

    The origin of 2DEG appearing at the TiO2-LaO (n-type) interface between two insulating oxides of polar LaAlO3 (LAO) and nonpolar SrTiO3 (STO) after some critical LAO thickness is still under hot debate. Here applying modern defect theory for bulk, interface and surface, based on DFT and HSE, we investigated the current mechanisms that focus on polar catastrophe scenario, interfacial and surface O vacancies (VO), or interfacial cation defects. We uncovered a unified mechanism that can explain not only the 2DEG at n-type interface, but also the insulating behaviour at SrO/AlO2 (p-type) interface. Specifically, for n-type interface, we found that (i) it is the VO at LAO surface coupled with built-in electric field in LAO film that causes 2DEG and determines the critical thickness. (ii) The interfacial La-on-Sr and Ti-on-Al antisite donor defects cause interfacial mixing, but do not contribute itinerant carriers. (iii) The cation vacancies and acceptor antisite defects can trap partially the 2DEG. For p-type interface, the insulating behaviour is resulted from the spontaneous formation of the defect pair of ``interfacial La-on-Sr defect and surface La vacancy defect'' after a critical thickness smaller than that expected from pure polar catastrophe scenario. Supported by DOE BES Energy Frontier Research Center for Inverse Design.

  14. The synthesis and the luminescence properties of Sr2Ga3La1-xDyxGe3O14

    Science.gov (United States)

    Wang, Qiang; Mu, Zhongfei; Yang, Lurong; Zhang, Shaoan; Zhu, Daoyun; Yang, Yibin; Luo, Dongxiang; Wu, Fugen

    2018-02-01

    A series of Sr2Ga3La1-xDyxGe3O14 (x = 0, 0.015, 0.03, 0.045, 0.06, 0.075, 0.09) phosphors were synthesized by high temperature solid state reactions. X-ray diffraction analysis proves that single-phase Sr2Ga3La1-xDyxGe3O14 (0 ≤ x ≤ 0.09) has been obtained. The particle size of these powders is in the range from 1 to 3 μm. The host Sr2Ga3LaGe3O14 emits blue white light under the excitation of 260 nm ultraviolet light. Dy3+ doped samples can be effectively excited with near ultraviolet light and exhibit two emission bands in the blue (4F9/2 → 6H15/2) and yellow regions (4F9/2 → 6H13/2), which can form white light. Present research indicates that Dy3+ doped Sr2Ga3LaGe3O14 have the potential to be a single-phase full-color emitting phosphor.

  15. Strategies for Overcoming Barriers Inherent in Cross-Cultural Research (Doing Research).

    Science.gov (United States)

    Jameson, Daphne A.

    1994-01-01

    Raises concerns about unexamined conceptual assumptions and over-generalizations of research findings in the comparative management area. Suggests two ways of combating these problems: collaboration and accounting for complexities of culture. (SR)

  16. Experimental evidence shows no fractionation of strontium isotopes ((87)Sr/(86)Sr) among soil, plants, and herbivores: implications for tracking wildlife and forensic science.

    Science.gov (United States)

    Flockhart, D T Tyler; Kyser, T Kurt; Chipley, Don; Miller, Nathan G; Norris, D Ryan

    2015-01-01

    Strontium isotopes ((87)Sr/(86)Sr) can be useful biological markers for a wide range of forensic science applications, including wildlife tracking. However, one of the main advantages of using (87)Sr/(86)Sr values, that there is no fractionation from geological bedrock sources through the food web, also happens to be a critical assumption that has never been tested experimentally. We test this assumption by measuring (87)Sr/(86)Sr values across three trophic levels in a controlled greenhouse experiment. Adult monarch butterflies were raised on obligate larval host milkweed plants that were, in turn, grown on seven different soil types collected across Canada. We found no significant differences between (87)Sr/(86)Sr values in leachable Sr from soil minerals, organic soil, milkweed leaves, and monarch butterfly wings. Our results suggest that strontium isoscapes developed from (87)Sr/(86)Sr values in bedrock or soil may serve as a reliable biological marker in forensic science for a range of taxa and across large geographic areas.

  17. Tectonic forcing of early to middle jurassic seawater Sr/Ca

    DEFF Research Database (Denmark)

    Ullmann, Clemens Vinzenz; Hesselbo, Stephen P.; Korte, Christoph

    2013-01-01

    The Jurassic Period (ca. 201–145 Ma) is marked by fundamental reorganizations of paleogeography, paleoceanography, ecosystems, and the progressive shift from aragonite to calcite as the favored marine biogenic carbonate polymorph. Sr/Ca ratios of well-preserved Jurassic oysters and belemnites from...... sections in the UK and Poland demonstrate that the Sr/Ca ratio of seawater varied systematically throughout the Early and Middle Jurassic in parallel with already documented seawater 87Sr/86Sr. The Sr flux from increased mid-ocean ridge activity in the Early Jurassic outbalanced the input of riverine Sr...

  18. A new synthesis route of perovskite-related Sr2TaO3N oxynitride via Sr2Ta6O10.188

    Science.gov (United States)

    Sarda, Narendra G.; Hayashi, Takanori; Takeuchi, Yuta; Harada, Kyosuke; Murai, Kei-Ichiro; Moriga, Toshihiro

    2016-12-01

    Formation process of the new layered perovskite Sr2TaO3N oxynitride having a K2NiF4-type structure from oxide precursor of Sr6Ta2O10.188 was examined under an ammonia flow. Using the oxide precursor, it is possible to make a Sr2TaO3N phase within a shorter period of the nitridation than the previous paper reported by Marchant et al. (J. Solid State Chem., 146: 390-393(1999)). Excess amount of strontium deviated from the stoichiometric composition of Sr/Ta=2 also seemed to promote the formation of Sr2TaO3N under the ammonia flow. The synthesized Sr2TaO3N after two cycles of 24h-nitridation of the oxide precursors showed brighter reddish-orange color than SrTaO2N.

  19. Data report for the safety assessment SR-Can

    Energy Technology Data Exchange (ETDEWEB)

    Vahlund, Fredrik [Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden); Andersson, Johan [JA Streamflow AB, Aelvsjoe (Sweden); Loefgren, Martin [Kemakta Konsult AB, Stockholm (Sweden)

    2006-11-15

    This report is the data report derived within the project SR-Can. The purpose of the data report is to present input data, with uncertainty estimates, for the SR-Can assessment calculations. Data presented in the report have been derived using standardised procedures following a methodology which is presented in the initial part of the report. In this part, a template is presented that has been used when assessing input data in supporting documents as illustrated in subsequent chapters of the data report. By using the template, decisions by the SR-Can team are separated from expert input. This increases the traceability of assessment decisions. The data report supplies assessment data for all parts of the repository system, the fuel, the canister, the buffer and backfill and the geosphere. For the geosphere, many of the data are based on information obtained during the site investigation programme.

  20. Evidence of ferroelectricity in SrFeO3-δ

    Science.gov (United States)

    Manimuthu, P.; Venkateswaran, C.

    2012-01-01

    Perovskite SrFeO3-δ belongs to the Ruddlesden-Popper class of system exhibiting interesting electronic and magnetic properties. Nanocrystalline SrFeO3-δ synthesized successfully by the thermal decomposition method has the cubic phase as confirmed from x-ray diffraction. The non-stoichiometric nature is confirmed from the selected area electron diffraction pattern. Oxygen stoichiometry, which plays an important role in determining the physical properties, was found to be 2.91 from the iodometric titration. Mössbauer measurement reveals paramagnetic behaviour and suggests mixed valence state of Fe. Relaxor type ferroelectricity is evident from the dielectric plots, which is also reflected in the thermal study. Relaxor ferroelectric behaviour is reported for the first time in SrFeO2.91, arising due to mixed valency of Fe ion.

  1. Additional Sr Isotopic Heterogeneity in Zagami Olivine-Rich Lithology

    Science.gov (United States)

    Misawa, K.; Niihara, T.; Shih, C.-Y; Reese, Y. D.; Nyquist, L. E.; Yoneda, S.; Yamashita, H.

    2012-01-01

    Prior isotopic analyses of Zagami have established differing initial Sr-87/Sr-86 (ISr) ratios of among Zagami lithologies, fine-grained (FG), coarse-grained (CG), and dark mottled lithologies (DML)]. The Zagami sample (KPM-NLH000057) newly allocated from the Kanagawa Prefectural Museum of Natural History contained DML and the Ol-rich lithology which included more ferroan olivines (Ol-rich: Fa(sub 97- 99) vs late-stage melt pockets: Fa(sub 90-97)]). We have combined mineralogy-petrology and Rb-Sr isotopic studies on the Kanagawa Zagami sample, which will provide additional clues to the genesis of enriched shergottites and to the evolution of Martian crust and mantle

  2. Epitaxial growth and thermodynamic stability of SrIrO{sub 3}/SrTiO{sub 3} heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Groenendijk, D. J., E-mail: d.j.groenendijk@tudelft.nl; Manca, N.; Mattoni, G.; Kootstra, L.; Caviglia, A. D. [Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft (Netherlands); Gariglio, S. [Department of Quantum Matter Physics, University of Geneva, 24 Quai Ernest-Ansermet, 1211 Genève 4 (Switzerland); Huang, Y.; Heumen, E. van [Van der Waals-Zeeman Institute, Institute of Physics (IoP), University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands)

    2016-07-25

    Obtaining high-quality thin films of 5d transition metal oxides is essential to explore the exotic semimetallic and topological phases predicted to arise from the combination of strong electron correlations and spin-orbit coupling. Here, we show that the transport properties of SrIrO{sub 3} thin films, grown by pulsed laser deposition, can be optimized by considering the effect of laser-induced modification of the SrIrO{sub 3} target surface. We further demonstrate that bare SrIrO{sub 3} thin films are subject to degradation in air and are highly sensitive to lithographic processing. A crystalline SrTiO{sub 3} cap layer deposited in-situ is effective in preserving the film quality, allowing us to measure metallic transport behavior in films with thicknesses down to 4 unit cells. In addition, the SrTiO{sub 3} encapsulation enables the fabrication of devices such as Hall bars without altering the film properties, allowing precise (magneto)transport measurements on micro- and nanoscale devices.

  3. Effect of SR manipulation on conduit artery dilation in humans.

    Science.gov (United States)

    Carter, Howard H; Dawson, Ellen A; Birk, Gurpreet K; Spence, Angela L; Naylor, Louise H; Cable, N Timothy; Thijssen, Dick H J; Green, Daniel J

    2013-01-01

    The impact of manipulating shear stress on conduit artery vasodilation has not been comprehensively described in vivo. We hypothesized that manipulation of SR through the brachial and radial arteries would be associated with corresponding changes in diameter. We performed a series of studies involving the following: (1) leg cycle exercise at increasing intensities (≈70 and 85% maximum heart rate [HRmax]) with simultaneous bilateral measurement of SR in the radial arteries; (2) leg cycle exercise for 30 minutes at 80% HRmax with simultaneous bilateral measurement of velocity and diameter in the brachial arteries; and (3) bilateral forearm heating for 30 minutes with simultaneous bilateral measurement of brachial artery diameter and blood velocity. Cycling and forearm heating interventions were performed in the presence of unilateral cuff inflation throughout the experiment, or starting during the intervention (15 minutes), to manipulate SR responses. Cuff placement was associated with lower radial artery SR responses (cuffed versus uncuffed, 248±49 versus 349±105 L/s 85% HRmax; P<0.01), and diameter responses were similarly attenuated (2.45±0.30 versus 2.78±0.20 mm 85% HRmax; P<0.05). Exercise performed at 80% HRmax in the presence of unilateral cuff inflation also reduced brachial artery SR (cuffed versus uncuffed; 258±107 versus 454±157 L/s; P<0.01) and diameter (3.96±0.39 versus 4.20±0.45 mm). Finally, cuff inflation decreased the impact of forearm heating on brachial SR (cuffed versus uncuffed; 262±97 versus 440±106 L/s; P<0.01) and diameter (4.35±0.54 versus 4.87±0.47 mm; P<0.05). Similar significant differences between the cuffed and uncuffed limbs in SR and diameter were observed when cuff inflation occurred during exercise or heating. Our findings strongly implicate SR as an important stimulus to increase conduit artery diameter in humans.

  4. PRODUCTION OF PLANTARCIN BY LACTOBACILLUS PLANTARUM SR18

    OpenAIRE

    Wagih El-Shouny; Amal Abo-Kamar; Abd El-Raheem El-Shanshoury; Suzan Ragy

    2012-01-01

    Out of 86 lactobacilli previously screened in our laboratory, Lactobacillus plantarum SR18 isolated from yoghurt revealed the largest detected inhibition zone against the selected indicator Streptococcus salivarius 5. The obtained electrophoretic patterns revealed that L. plantarum SR18 was free from plasmids. Exposure of 6 h growing L. plantarum culture to T-8M, 3B ultraviolet B lamp (8w, 220v & 312 nm) for 2 h and subsequent growth for further 24 h resulted in an increase of cell-bound ...

  5. Temperature effect on the retention of U(VI) by SrTiO{sub 3}; Effet de la temperature sur la retention de U(VI) par SrTiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Rosales, G

    2007-11-15

    The purpose of this research was the study of the interaction mechanisms between U(VI) ions and SrTiO{sub 3} surfaces versus pH and temperature: 25, 50, 75 and 90 C. Firstly, a physicochemical characterization was realized (DRX, MEB, FTIR) and the surface site density was determined. The potentiometric titration data were simulated, for each temperature, using the constant capacitance model and taking into account bath protonation of the {identical_to}Sr-OH surface sites and deprotonation of the {identical_to}Ti-OH ones (one pK{sub a} model). Both enthalpy and entropy changes, corresponding to the surface acid-base reactions, were evaluated using the van't Hoff relation. U(VI) was sorbed onto SrTiO{sub 3} powder in the pH range 0.5-5.0 with an U(VI) initial concentration 1.10{sup -4} M. By TRLIFS two U(VI) complexes were detected associated with two lifetime values (60 {+-} 5 and 12 {+-} 2 {mu}s at 25 C). The sorption edges were simulated using FITEQL 4.0 software. The surface complexation constants of the system SrTiO{sub 3}/U(VI) between 25 and 90 C temperature range were thus obtained with the constant capacitance model considering two reactive surface sites. It reveals that two types of surface complex, namely [({identical_to}SrOH)({identical_to}TiOH)UO{sub 2}]{sup 2+} and [({identical_to}TiOH)({identical_to}TiO)UO{sup 2+}]{sup 2+}, are needed to properly describe the experimental observations. By application of the van't Hoff equation, Delta{sub R}S{sup 0} and Delta{sub R}H{sup 0} were obtained, which indicated an endothermic sorption process. Finally, an energy transfer study was realised by TRLIFS. The energy transfer between Tb{sup 3+} and Eu{sup 3+} ions sorbed onto SrTiO{sub 3} powders were investigated. The results showed that the energy transfer between Tb{sup 3+} and Eu{sup 3+} is a non-radiative process and follows a dipole-dipole type interaction. A formalism based on the Dexter and the Inokuti-Hirayama theories was used to calculate the

  6. Modelling the Phanerozoic carbon cycle and climate - Constraints from the Sr-87/Sr-86 isotopic ratio of seawater

    Science.gov (United States)

    Francois, Louis M.; Walker, James C. G.

    1992-01-01

    A numerical model is developed for simulating the long-term changes of atmospheric CO2 and climate during the Phanerozoic. The model describes the coupled evolution of the biogeochemical cycles of C, S, Ca, Mg, P, and Sr, with the emphasis on the effect of coupling the cycles of carbon and strontium and on interpreting the observed seawater Sr-87/Sr-86 ratios. The abilities of continental weathering, volcanism, and surface lithology in generating that signal are tested and compared. The results obtained are used to reconstruct a history of atmospheric CO2 and climate during Phanerozoic time, consistent with the strontium isotopic data. It is shown that the predicted history is compatible with paleoclimatic indicators, such as the timing of glaciation and the estimates of Cretaceous paleotemperatures.

  7. The radiogenic and stable Sr isotope geochemistry of basalt weathering in Iceland: Role of hydrothermal calcite and implications for long-term climate regulation

    Science.gov (United States)

    Andrews, M. Grace; Jacobson, Andrew D.

    2017-10-01

    Several studies have examined the geochemistry of Icelandic rivers to quantify the relationship between basalt weathering and long-term climate regulation. Recent research has suggested that the chemical weathering of hydrothermal and metamorphic calcite contributes significant quantities of HCO3- to the Icelandic riverine flux (Jacobson et al., 2015). Because the HCO3- derives from volcanic CO2 that was sequestered in mineral form prior to atmospheric injection, the strength of the basalt weathering feedback occurring in Iceland may be lower than previously realized. To test these hypotheses, we analyzed the radiogenic and stable Sr isotope composition (87Sr/86Sr and δ88/86Sr) of the same suite of water, rock, and mineral samples as examined in Jacobson et al. (2015), and we developed a simple model of the long-term C cycle that considers the transformation of volcanic CO2 to HCO3- during subsurface silicate weathering, which is a precursor to hydrothermal calcite formation. Interpretations based on 87Sr/86Sr and Ca/Sr ratios suggest that conservative, three-component mixing between basalt, calcite, and atmospheric deposition adequately explains river geochemistry. On average, the δ88/86Sr values of glacial and non-glacial rivers (0.414‰ and 0.388‰, respectively) are generally higher than those for basalt (0.276‰); however, calcite δ88/86Sr values (0.347‰) are also higher than those for basalt and span the range of riverine values. Thus, riverine δ88/86Sr values are also consistent three-component mixing between basalt, calcite, and atmospheric deposition. Isotopic fractionation is not required to explain riverine trends. Finally, model equations for the long-term C cycle demonstrate that subsurface silicate weathering reduces the magnitude of the volcanic CO2 degassing flux, which in turn causes the atmosphere to stabilize at lower pCO2 values compared to the case where no subsurface silicate weathering occurs. However, the proportion of the net

  8. Igneous Consequence Modeling for the TSPA-SR

    Energy Technology Data Exchange (ETDEWEB)

    John McCord

    2001-10-29

    The purpose of this technical report is to develop credible, defendable, substantiated models for the consequences of igneous activity for the TSPA-SR Model. The effort will build on the TSPA-VA and improve the quality of scenarios and depth of the technical basis underlying disruptive events modeling. Computational models for both volcanic eruptive releases (this is an event that results in ash containing waste being ejected from Yucca Mountain) and igneous intrusion groundwater releases (this is an event that reaches the repository level, impacts the waste packages, and produces releases from waste packages damaged by igneous activity) will be included directly in the TSPA calculations as part of the TSPA-SR Model. This Analysis Model Report (AMR) is limited to development of the conceptual models for these two scenarios. The mathematical implementation of these conceptual models will be done within the TSPA-SR Model. Thus, this AMR will not include any model results or sensitivity analyses. Calculation of any doses resulting from igneous releases will also be done within the TSPA-SR model, as will the probabilistic weighting of these doses. Calculation and analysis of the TSPA-SR Model results for igneous disruption are, therefore, outside the scope of this activity. The reason for not running the mathematical models as part of this AMR is that the models are integrated within the TSPA-SR model and, thus, any model simulations and the corresponding results are out of the scope of this AMR. The scope of this work as defined in the development plan (CRWMS M&O 2000j) involves using data that has been extracted from existing sources to design and support the TSPA-SR models for the transport of radionuclides following igneous disruption of the repository. The development plan states ''applications of the code in this analysis will be limited to testing of the code and sensitivity analyses during analysis design.'' In contrast to the development

  9. DISEÑO E IMPLEMENTACIÓN DE UNA BASE DE DATOS DE IMÁGENES DE RANGO CON DECIMACIÓN PARA LA VISUALIZACIÓN EN WEB DESIGN AND IMPLEMENTATION OF A RANGE IMAGES DATABASE WITH DECIMATION TO BE VISUALIZED IN THE WEB

    Directory of Open Access Journals (Sweden)

    Isabel Rodríguez

    2007-07-01

    Full Text Available Las bases de datos son una herramienta para administrar y almacenar la información, mientras mejor esté distribuida, más fácil y eficiente será el acceso a esta. En la actualidad, y gracias al desarrollo tecnológico de campos como la informática y la electrónica, la mayoría de las bases de datos tienen formato electrónico, ya que ofrece un amplio rango de soluciones al problema de almacenar datos. En este artículo, presentamos el diseño de una base de datos para imágenes de rango, basada en el modelo relacional y una metodología de diseño consistente en tres pasos: diseño conceptual, diseño lógico y diseño físico. Dicha base de datos cuenta con acceso vía Web. Un algoritmo de multirresolución fue desarrollado e implementado para mejorar el costo computacional en visualización y renderización, utilizando parámetros de decimación basados en curvatura. Se desarrolló una plataforma Web para el acceso de forma amigable a la base de datos para que se puedan ingresar, actualizar y eliminar modelos, de forma confiable y sencilla. Actualmente, la base de datos cuenta con 40 modelos divididos en 3 categorías: rostros (22, museo (4 y objetos de forma libre (14. El algoritmo de multirresolución usado, arrojó resultados de ahorro en costo computacional hasta del 96%.Databases are tools to store and manage information, the better they are distributed, the easier and more efficient will its access be. At present, thanks to technological development of fields such as computer science and electronics, most of them have an electronic format, since they offer a wide rank of solutions to the store data problem. In this paper, we present the design and development of a database for range images, based on the relational model and a design methodology consisting of three steps: conceptual design, logical design, and physical design. The data base has a WEB access. A multi-resolution algorithm was developed to improve the time cost in

  10. Tracking seasonal subglacial drainage evolution of alpine glaciers using radiogenic Nd and Sr isotope systematics: Lemon Creek Glacier, Alaska

    Science.gov (United States)

    Clinger, A. E.; Aciego, S.; Stevenson, E. I.; Arendt, C. A.

    2014-12-01

    The transport pathways of water beneath a glacier are subject to change as melt seasons progress due to variability in the balance between basal water pressure and water flux. Subglacial hydrology has been well studied, but the understanding of spatial distribution is less well constrained. Whereas radiogenic isotopic tracers have been traditionally used as proxies to track spatial variability and weathering rates in fluvial and riverine systems, these techniques have yet to be applied extensively to the subglacial environment and may help resolve ambiguity in subglacial hydrology. Research has shown the 143Nd/144Nd values can reflect variation in source provenance processes due to variations in the age of the continental crust. Correlating the 143Nd/144Nd with other radiogenic isotope systematics such as strontium (87Sr/86Sr) provides important constraints on the role of congruent and incongruent weathering processes. Our study presents the application of Nd and Sr systematics using isotopic ratios to the suspended load of subglacial meltwater collected over a single melt season at Lemon Creek Glacier, USA (LCG). The time-series data show an average ɛNd ~ -6.83, indicating a young bedrock (~60 MYA). Isotopic variation helps track the seasonal expansion of the subglacial meltwater channels and subsequent return to early season conditions due to the parabolic trend towards less radiogenic Nd in June and towards more radiogenic Nd beginning in mid-August. However, the high variability in July and early August may reflect a mixture of source as the channels diverge and derive sediment from differently aged lithologies. We find a poor correlation between 143Nd/144Nd and 87Sr/86Sr (R2= 0.38) along with a slight trend towards more radiogenic 87Sr/86Sr values with time ((R2= 0.49). This may indicate that, even as the residence time decreases over the melt season, the LCG subglacial system is relatively stable and that the bedrock is congruently weathered. Our study

  11. Step velocity tuning of SrRuO3 step flow growth on SrTiO3

    OpenAIRE

    Estève, D.; Maroutian, T.; Pillard, V.; Lecoeur, Ph.

    2011-01-01

    Taking advantage of vicinal (001) SrTiO3 substrates with different mean terrace widths, the heteroepitaxial growth of SrRuO3 in the step flow mode has been mapped as a function of mean step velocity. Transition between stable and unstable step flow is shown to occur at a well-defined critical step velocity, with a step bunching instability observed below this threshold. The ability to pass from unstable to stable step flow during growth upon increasing the mean step velocity is demonstrated. ...

  12. Researching research

    DEFF Research Database (Denmark)

    Pais, Alexandre; Valero, Paola

    2012-01-01

    of research by deploying Foucault’s notion of bio-politics - mainly to address the object “learning” - and Žižek’s ideology critique - to address the object “mathematics”. These theories, which have already been used in the field to research teaching and learning, have a great potential to contribute...

  13. Strong elasticoluminescence from monoclinic-structure SrAl2O4

    Science.gov (United States)

    Xu, Chao-Nan; Yamada, Hiroshi; Wang, Xusheng; Zheng, Xu-Guang

    2004-04-01

    Elastico-deformation luminescence in strontium aluminates was investigated systematically using precisely controlled pure-phase Eu-doped strontium aluminates of SrAl12O19, Sr4Al14O25, SrAl4O7, α-SrAl2O4, β-SrAl2O4, Sr3Al2O6 and their mixed phases. This study revealed that only the α-SrAl2O4 phase produces strong elastico-deformation luminescence; other strontium aluminates show no deformation luminescence. Correlation of deformation luminescence and crystal structure was found. The α-SrAl2O4 has the lowest symmetry, crystallizing in a monoclinic structure. This finding can be applied in designing strong elastico-deformation-luminescent materials.

  14. Core level photoemission spectroscopy and chemical bonding in Sr2Ta2O7

    DEFF Research Database (Denmark)

    Atuchin, V. V.; Grivel, Jean-Claude; Zhang, Z. M.

    2009-01-01

    -O bonds was characterized by the binding energy differences between the O 1s and cation core levels, Delta(O-Sr) = BE(O 1s) - BE(Sr 3d(5/2)) and Delta(O-Ta) = BE(O 1s) - BE(Ta 4f(7/2)). The chemical bonding effects were considered on the basis of our XPS results for Sr2Ta2O7 and earlier published...... structural and XPS data for other Sr- and Ta-containing oxide compounds. The new data point for Sr2Ta2O7 is consistent with the previously derived relationship for a set of Sr-bearing oxides. The binding energy difference Delta(O-Sr) was found to decrease with increasing bond distance L(Sr-O)....

  15. Electronic parameters of Sr2Nb2O7 and chemical bonding

    DEFF Research Database (Denmark)

    Atuchin, V.V.; Grivel, Jean-Claude; Korotkov, A.S.

    2008-01-01

    /2)) and Delta(O-Sr) = BE(O 1s)-BE(Sr 3d(5/2)), were used to characterize the valence electron transfer on the formation of the Nb-O and Sr-O bonds. The chemical bonding effects were considered on the basis of our XPS results for Sr2Nb2O7 and earlier published structural and XPS data for other Sr- or Nb......-containing oxide compounds. The new data point for Sr2Nb2O7 is consistent with the previously derived relationship for a set of Nb5+ -niobates that Delta (O-Nb) increases with increasing mean Nb-O bond distance, L(Nb-O). A new empirical relationship between Delta(O-Sr) and L(Sr-O) was also obtained. Interestingly...

  16. A novel synthesis of SrCO{sub 3}–SrTiO{sub 3} nanocomposites with high photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Márquez-Herrera, A., E-mail: amarquez@ugto.mx [Universidad de Guanajuato, Departamento de Ingeniería Mecánica Agrícola, DICIVA, Campus Irapuato-Salamanca (Mexico); Ovando-Medina, Víctor M.; Castillo-Reyes, Blanca E. [Universidad Autónoma de San Luis Potosí, Ingeniería Química, COARA (Mexico); Meléndez-Lira, M. [CINVESTAV-IPN, Departamento de Física (Mexico); Zapata-Torres, M. [Centro de Investigación en Ciencia Aplicada y Tecnología Avanzada (Mexico); Saldaña, N. [Universidad de Guanajuato, Departamento de Ingeniería Mecánica Agrícola, DICIVA, Campus Irapuato-Salamanca (Mexico)

    2014-12-15

    The results of the production and characterization of SrCO{sub 3}–SrTiO{sub 3} nanocomposites as a promising candidate for efficient photocatalysts are reported. The production is based on a novelty route employing the solvothermal method with strontium chloride and titanium (IV) butoxide as the precursor solutions. The effect on the properties of the nanocomposites due to changes in the content of SrCO{sub 3} and SrTiO{sub 3} is reported. The as-prepared materials were tested in the photodegradation of methylene blue dye in aqueous solutions under the solar light. The reported route allows the production of SrCO{sub 3}–SrTiO{sub 3} nanocomposites with particle sizes ranging between 18 and 29 nm. The SrCO{sub 3}–SrTiO{sub 3} nanocomposites obtained with 19 % of SrCO{sub 3} phase and 81 % of SrTiO{sub 3} (M10) can achieve 94 and 97 % of dye photodegradation after 30 and 120 min, respectively.

  17. Cluster emission in superdeformed Sr isotopes in the ground state ...

    Indian Academy of Sciences (India)

    2017-01-03

    Jan 3, 2017 ... Abstract. Cluster decay of superdeformed 76,78,80Sr isotopes in their ground state are studied taking the Coulomb and proximity potential as the interacting barrier for the post-scission region. The predicted T1/2 values are found to be in close agreement with those values reported by the preformed cluster ...

  18. Traveling-wave deceleration of SrF molecules

    NARCIS (Netherlands)

    van den Berg, J.E.; Chirayath Mathavan, Sreekanth; Meinema, C.; Nauta, Janko; Nijbroek, T. H.; Jungmann, K.; Bethlem, H. L.; Hoekstra, S.

    We report on the production, deceleration and detection of a SrF molecular beam. The molecules are captured from a supersonic expansion and are decelerated in the X-2 Sigma(+) (v = 0, N = 1) state. We demonstrate the removal of up to 40% of the kinetic energy with a 2 m long modular traveling-wave

  19. Pulsed laser ablation of LaSrCoO

    NARCIS (Netherlands)

    Span, E.A.F.; Roesthuis, Frank J.G.; Blank, David H.A.; Rogalla, Horst

    1999-01-01

    The ablation process of La0.5Sr0.5CoO3 by a spatial uniform 248 nm excimer laser beam has been characterized. Ablation rates, changes in the target surface morphology and composition have been studied as a function of the laser fluence. The dependence of the ablation rate on the laser fluence has

  20. IR study of Pb–Sr titanate borosilicate glasses

    Indian Academy of Sciences (India)

    Administrator

    to study their structure systematically. IR spectrum of each glass composition shows a number of absorption bands. These bands are strongly influenced by the increasing substitution of SrO for PbO. Various bands shift with composition. Absorption peaks occur due to the vibrational mode of the borate network in these ...

  1. Monazite-type SrCrO4 under compression

    CERN Document Server

    Gleissner, J; Segura, A; Pellicer-Porres, J; Hakeem, M A; Proctor, J; Raju, S V; Kumar, R S; Rodriguez-Hernandez, P; Munoz, A; Lopez-Moreno, S; Bettinelli, M

    2016-01-01

    We report a high-pressure study of monoclinic monazite-type SrCrO4 up to 26 GPa. Therein we combined x-ray diffraction, Raman and optical-absorption measurements with ab initio calculations, to find a pressure-induced structural phase transition of SrCrO4 near 8-9 GPa. Evidence of a second phase transition was observed at 10-13 GPa. The crystal structures of the high-pressure phases were assigned to the tetragonal scheelite-type and monoclinic AgMnO4-type structures. Both transitions produce drastic changes in the electronic band gap and phonon spectrum of SrCrO4. We determined the pressure evolution of the band gap for the low-pressure and high-pressure phases as well as the frequencies and pressure dependences of the Raman-active modes. In all three phases most Raman modes harden under compression; however the presence of low-frequency modes which gradually soften is also detected. In monazite-type SrCrO4, the band gap blue-shifts under compression, but the transition to the scheelite phase causes an abrupt...

  2. LCAO calculations of SrTiO3 nanotubes

    Science.gov (United States)

    Evarestov, Robert; Bandura, Andrei

    2011-06-01

    The large-scale first-principles simulation of the structure and stability of SrTiO3 nanotubes is performed for the first time using the periodic PBE0 LCAO method. The initial structures of the nanotubes have been obtained by the rolling up of the stoichiometric SrTiO3 slabs consisting of two or four alternating (001) SrO and TiO2 atomic planes. Nanotubes (NTs) with chiralities (n,0) and (n,n) have been studied. Two different NTs were constructed for each chirality: (I) with SrO outer shell, and (II) with TiO2 outer shell. Positions of all atoms have been optimized to obtain the most stable NT structure . In the majority of considered cases the inner or outer TiO2 shells of NT undergo a considerable reconstruction due to shrinkage or stretching of interatomic distances in the initial cubic perovskite structure. There were found two types of surface reconstruction: (1) breaking of Ti-O bonds with creating of Ti = O titanyl groups in outer surface; (2) inner surface folding due to Ti-O-Ti bending. Based on strain energy calculations the largest stability was found for (n,0) NTs with TiO2 outer shell.

  3. LCAO calculations of SrTiO{sub 3} nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Evarestov, Robert; Bandura, Andrei, E-mail: re1973@re1973.spb.edu [Department of Quantum Chemistry, St. Petersburg State University, 26 Universitetsky Ave., 198504, Petrodvorets (Russian Federation)

    2011-06-23

    The large-scale first-principles simulation of the structure and stability of SrTiO{sub 3} nanotubes is performed for the first time using the periodic PBE0 LCAO method. The initial structures of the nanotubes have been obtained by the rolling up of the stoichiometric SrTiO{sub 3} slabs consisting of two or four alternating (001) SrO and TiO{sub 2} atomic planes. Nanotubes (NTs) with chiralities (n,0) and (n,n) have been studied. Two different NTs were constructed for each chirality: (I) with SrO outer shell, and (II) with TiO{sub 2} outer shell. Positions of all atoms have been optimized to obtain the most stable NT structure . In the majority of considered cases the inner or outer TiO{sub 2} shells of NT undergo a considerable reconstruction due to shrinkage or stretching of interatomic distances in the initial cubic perovskite structure. There were found two types of surface reconstruction: (1) breaking of Ti-O bonds with creating of Ti = O titanyl groups in outer surface; (2) inner surface folding due to Ti-O-Ti bending. Based on strain energy calculations the largest stability was found for (n,0) NTs with TiO{sub 2} outer shell.

  4. ADEPT Sounding Rocket One (SR-1)Flight Experiment Overview

    Science.gov (United States)

    Wercinski, Paul; Smith, B.; Yount, B.; Cassell, A.; Kruger, C.; Brivkalns, C.; Makino, A.; Duttta, S.; Ghassemieh, S.; Wu, S.; hide

    2017-01-01

    The SR-1 flight experiment will demonstrate most of the primary end-to-end mission stages including: launch in a stowed configuration, separation and deployment in exo-atmospheric conditions, and passive ballistic re-entry of a 70-degree half-angle faceted cone geometry.

  5. Synthesis of BiPbSrCaCuO superconductor

    Science.gov (United States)

    Hults, William L.; Kubat-Martin, Kimberly A.; Salazar, Kenneth V.; Phillips, David S.; Peterson, Dean E.

    1994-01-01

    A process and a precursor composition for preparing a lead-doped bismuth-strontium-calcium-copper oxide superconductor of the formula Bi.sub.a Pb.sub.b Sr.sub.c Ca.sub.d Cu.sub.e O.sub.f wherein a is from about 1.7 to about 1.9, b is from about 0.3 to about 0.45, c is from about 1.6 to about 2.2, d is from about 1.6 to about 2.2, e is from about 2.97 to about 3.2 and f is 10.+-.z by reacting a mixture of Bi.sub.4 Sr.sub.3 Ca.sub.3 Cu.sub.4 O.sub.16.+-.z, an alkaline earth metal cuprate, e.g., Sr.sub.9 Ca.sub.5 Cu.sub.24 O.sub.41, and an alkaline earth metal plumbate, e.g., Ca.sub.2-x Sr.sub.x PbO.sub.4 wherein x is about 0.5, is disclosed.

  6. mu SR in Organic and Free Radical Chemistry

    CERN Multimedia

    2002-01-01

    Experiment SC82 was begun as a simple attempt to substitute positive muons into polymer molecules, and thereby to use the @mSR technique to study the mechanical relaxation of the different molecular groups. \\\\ \\\\ The experiment has since developed in several directions and has produced a wealth of information on the properties of muonic molecules, and adequately demonstrated the potential of @mSR as applied to molecular physics and chemistry. Physics aspects are now covered by a new experiment code SC95.\\\\ \\\\ The present experiment includes studies where the position occupied by the muon in the molecule (or crystal lattice) is readily established and the @mSR signal is exploited to reveal the intrinsic properties of the material. In this respect the @mSR techniques may be regarded simply as an experimental tool to probe the molecular behaviour of a chemical system. \\\\ \\\\ Two main classes of application include the measurement of isotope effects, where differences between muonic and corresponding photonic radi...

  7. Extreme heterogeneity in Sr isotope systematic in the Himalayan ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 110; Issue 2. Extreme heterogeneity in Sr isotope systematic in the Himalayan leucogranites: A possible mechanism of partial melting based on thermal modeling. Dilip K Mukhopadhyay. Volume 110 Issue 2 June 2001 pp 161-169 ...

  8. Assessment of Sr-90 in water samples: precision and accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Nisti, Marcelo B.; Saueia, Cátia H.R.; Castilho, Bruna; Mazzilli, Barbara P., E-mail: mbnisti@ipen.br, E-mail: chsaueia@ipen.br, E-mail: bcastilho@ipen.br, E-mail: mazzilli@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2017-11-01

    The study of artificial radionuclides dispersion into the environment is very important to control the nuclear waste discharges, nuclear accidents and nuclear weapons testing. The accidents in Fukushima Daiichi Nuclear Power Plant and Chernobyl Nuclear Power Plant, released several radionuclides in the environment by aerial deposition and liquid discharge, with various level of radioactivity. The {sup 90}Sr was one of the elements released into the environment. The {sup 90}Sr is produced by nuclear fission with a physical half-life of 28.79 years with decay energy of 0.546 MeV. The aims of this study are to evaluate the precision and accuracy of three methodologies for the determination of {sup 90}Sr in water samples: Cerenkov, LSC direct method and with radiochemical separation. The performance of the methodologies was evaluated by using two scintillation counters (Quantulus and Hidex). The parameters Minimum Detectable Activity (MDA) and Figure Of Merit (FOM) were determined for each method, the precision and accuracy were checked using {sup 90}Sr standard solutions. (author)

  9. Effect of SR manipulation on conduit artery dilation in humans

    NARCIS (Netherlands)

    Carter, H.H.; Dawson, E.A.; Birk, G.K.; Spence, A.L.; Naylor, L.H.; Cable, N.T.; Thijssen, D.H.J.; Green, D.J.

    2013-01-01

    The impact of manipulating shear stress on conduit artery vasodilation has not been comprehensively described in vivo. We hypothesized that manipulation of SR through the brachial and radial arteries would be associated with corresponding changes in diameter. We performed a series of studies

  10. Patterns of Ca/Sr and 87Sr/ 86Sr variation before and after a whole watershed CaSiO 3 addition at the Hubbard Brook Experimental Forest, USA

    Science.gov (United States)

    Nezat, Carmen A.; Blum, Joel D.; Driscoll, Charles T.

    2010-06-01

    Forty-one metric tons of the mineral wollastonite (CaSiO 3) was applied to an 11.8 hectare watershed at the Hubbard Brook Experimental Forest (HBEF; White Mountains, New Hampshire, USA) with the goal of restoring the Ca estimated to have been depleted from the soil exchange complex by acid deposition. This experiment provided an opportunity to gain qualitative information on whole watershed hydrologic flow paths by studying the response of stream water chemistry to the addition of Ca. Because the Ca/Sr and 87Sr/ 86Sr ratios of wollastonite strongly contrast that of other Ca sources in the watershed, the wollastonite-derived Ca can be identified and its amount estimated in various ecosystem components. Stream water chemistry at the HBEF varies seasonally due to shifts in the proportion of base flow and interflow. Prior to the wollastonite application, seasonal variations in 87Sr/ 86Sr ratios indicated that 87Sr/ 86Sr was higher during base flow than interflow, due largely to greater amounts of biotite weathering along deeper flow paths. After the application, Ca/Sr and 87Sr/ 86Sr changed markedly as the high Ca/Sr and low 87Sr/ 86Sr wollastonite dissolved and mixed with stream water. The Ca addition provided information on the response times of various flow paths and ion exchange processes to Ca addition in this small upland watershed. During the first year after the addition, wollastonite applied to the near stream zone dissolved and was partially immobilized by cation exchange sites in the hyporheic zone. In the second and third years after the addition we infer that much of this Ca and Sr was subsequently desorbed from the hyporheic zone and was exported from the watershed in stream flow. In the fourth through ninth years after the addition, Ca and Sr from wollastonite that had dissolved in upland soils was transported to the stream by interflow during wet periods when the ground water table was elevated. Between years three and nine the minimum annual Ca/Sr

  11. Enrichment of 88Sr in continental waters due to calcium carbonate precipitation

    Science.gov (United States)

    Shalev, Netta; Gavrieli, Ittai; Halicz, Ludwik; Sandler, Amir; Stein, Mordechai; Lazar, Boaz

    2017-02-01

    δ88/86Sr data published over the last few years suggest that continental waters are enriched with 88Sr as compared to the rocks in their drainage basins. In an attempt to understand this phenomenon, this study established the fractionation in the 88Sr/86Sr ratio during precipitation of continental carbonates (i.e., carbonates precipitated on land from surface, pedogenic, or ground waters), and evaluated the contribution of this process to the 88Sr-enrichment in rivers. For this, stable and radiogenic Sr isotopes (88Sr, 87Sr and 86Sr) were measured in calcite samples and their precipitating waters collected in various continental environments, such as soil, cave, streams and groundwater. The results indicate that continental carbonates are 88Sr-depleted relative to their precipitating waters, placing them as one of the most 88Sr-depleted reservoirs on earth. The average difference in δ88/86Sr values between waters and solid CaCO3 (tufas or speleothems) that they precipitate is Δcarb-water = - 0.218 ± 0.014 ‰ (1SD). An even larger fractionation (εcarb-water = - 0.285 ± 0.02 ‰) was measured in groundwater with particularly high carbonate-alkalinity and high carbonate precipitation rate that depleted ∼65% of the Sr in the groundwater, resulting in substantial 88Sr-enrichment in the residual dissolved Sr (δ88/86Sr = 0.656 ‰). Results also suggest that pedogenic carbonate precipitation in soil profile removes 50-85% of the Sr from the recharging soil-water, thereby increasing the δ88/86Sr value of the soil-water from ∼ 0.18 ‰ to 0.3 ‰- 0.6 ‰. Similar 88Sr-enrichment was observed in drip water from a karst cave. A maximum removal flux of Sr into continental carbonates of about 20 Gmol(Sr)ṡy-1 is required to yield the reported 88Sr-enrichment in global rivers (δ88/86Sr = 0.32 ‰) relative to their rock sources when using the fractionation factor derived in this study, Δcarb-water = - 0.218 ‰, and the published δ88/86Sr composition of marine

  12. Tracking chemical changes in a live cell: Biomedical applications of SR-FTIR spectromicroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Holman, Hoi-Ying N.; Martin, Michael C.; McKinney, Wayne R.

    2002-07-25

    Synchrotron radiation-based Fourier transform infrared (SR-FTIR) spectromicroscopy is a newly emerging bioanalytical and imaging tool. This unique technique provides mid-infrared (IR) spectra, hence chemical information, with high signal-to-noise at spatial resolutions as fine as 3 to 10 microns. Thus it enables researchers to locate, identify, and track specific chemical events within an individual living mammalian cell. Mid-IR photons are too low in energy (0.05 - 0.5 eV) to either break bonds or to cause ionization. In this review, we show that the synchrotron IR beam has no detectable effects on the short- and long-term viability, reproductive integrity, cell-cycle progression, and mitochondrial metabolism in living human cells, and produces only minimal sample heating (< 0.5 degrees C). We will then present several examples demonstrating the application potentials of SR-FTIR spectromicroscopy in biomedical research. These will include monitoring living cells progressing through the cell cycle, including death, and cells reacting to dilute concentrations of toxins.

  13. Properties of epitaxial LaMnO3/SrTiO3 interfaces.

    Science.gov (United States)

    Christen, Hans M.; Kim, Dae Ho; Lee, Ho Nyung; Varela, Maria; Petit, Leon; Schulthess, Thomas

    2007-03-01

    Electronic effects at interfaces between dissimilar oxides are known to have fundamental consequences on their transport and magnetic properties. Interfaces between the band insulator SrTiO3 and the antiferromagnetic charge-transfer insulator LaMnO3 provide a particularly interesting platform to test such effects. Both perovskites are grown epitaxially by pulsed-laser deposition, and electron energy loss spectra (EELS) collected in a scanning transmission electron microscope (STEM) show interfacial valence changes on the Mn-sites, while Ti remains in a 4+ state even in direct contact with the LaO layer of the LaMnO3. This observation is fully consistent with computational results obtained for such structures using the self-interaction corrected (SIC) local spin density (LSD) method. In this presentation, we discuss the physical origin and consequences of these valence changes in single interfaces as well as LaMnO3/SrTiO3 superlattices. This research was sponsored by the Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, U.S. Department of Energy, under contract DE-AC05-00OR22725 with Oak Ridge National Laboratory (ORNL), managed and operated by UT-Battelle, LLC, and ORNL's Laboratory Directed Research and Development Program.

  14. Sr isotopic variations in Upper Proterozoic carbonates from Svalbard and East Greenland

    Science.gov (United States)

    Derry, Louis A.; Keto, Lisette S.; Jacobsen, Stein B.; Knoll, Andrew H.; Swett, Keene

    1989-01-01

    Precambrian Sr isotope stratigraphy was investigated by determining variations in Sr-87/Sr-86 ratios in the Upper Proterozoic carbonate succession from Svalbard and East Greenland. Data from this study were combined with those from literature to construct a curve of Sr-87/Sr-86 versus time for Upper Proterozoic seawater. The curve for the Upper Riphean-Vandian showed that the isotopic composition of Sr in seawater was low (Delta Sr-87 of about -500) between 900 and 650 Ma but rose rapidly to about +30 by 600 Ma (this range of long-term variation exceeds the total Phanerozoic variation). The very low values of Delta Sr-87 inferred for the Riphean require that, for this time, the submarine hydrothermal water flux was a large fraction of the Sr input to the oceans, while the rise in Delta Sr-87 in the Upper Proterozoic seawater reflects both a change in the ratio of hydrothermal and continental fluxes of Sr to the oceans, and a change in the isotopic composition of Sr from continental sources.

  15. Rb- Sr isochron dating of granitoids from the Kazaure schist belt ...

    African Journals Online (AJOL)

    The results of Rb-Sr isochron dating of granites from the crystalline basement complex of Kazaure Schist Belt are presented in this paper. Whole rock Rb-Sr radiometric age determination of five samples of a syntectonic coarse-grained porphyritic granite define a 4-point whole-rock Rb-Sr isochron (MSWD=1.2) ...

  16. Synthesis of SrCrO4 nanostructures by onion inner-coat template ...

    Indian Academy of Sciences (India)

    This paper describes a bio-template method of the squama inner coat of onion for preparing the SrCrO4 nanostructures including nanospheres, nanorods and dumbbell-shaped superstructure. The method is able to make SrCrO4 nanoparticles with average diameters in the range of 90–170 nm, SrCrO4 nanorods with ...

  17. The influence of Sr on the microstructure, degradation and stress corrosion cracking of the Mg alloys - ZK40xSr.

    Science.gov (United States)

    Chen, Lianxi; Bin, Yuanhong; Zou, Wenqi; Wang, Xiaojian; Li, Wei

    2017-02-01

    In the present work, new magnesium (Mg) alloys (Mg-4Zn-0.6Zr-xSr, x=0, 0.4, 0.8, 1.2, 1.6wt%; ZK40xSr) were prepared and studied as potential biodegradable materials. The influence of strontium (Sr) addition on the properties of the new Mg alloys was investigated, which included microstructure, corrosion degradation, and the stress corrosion cracking (SCC) susceptibility. The average grain size of the ZK40Sr was approximately 100µm, which was significantly smaller than that of ZK40 alloy without Sr (402.3±40.2µm). The size of grain boundaries precipitates in the ZK40xSr alloys gradually increased with the increase of Sr content. The grain boundaries finally showed a continuously distribution and net-like shape. The degradation test showed that the average degradation rate of the ZK40xSr alloys increased with the increase of Sr addition. In the case of Mg-4Zn-0.6Zr, the degradation rate was 2.2mgcm-2day-1, which was lower than that of Mg-4Zn-0.6Zr-1.6Sr (4.93mgcm-2day-1). When the ZK40xSr alloys were immersed in m-SBF, the rod-like Sr-contained hydroxyapatite (HA) substance was detected, which was known to enhance cell growth around bone implants. The fracture surfaces of the as-cast Mg-4Zn-0.6Zr-1.6Sr were shown intergranular stress corrosion cracking (IGSCC) patterns. The increase of SCC susceptibility of the higher Sr ZK40xSr alloys was attributed to the increase of micro-galvanic corrosion between the α-Mg and the grain boundaries precipitates. The SCC susceptibility values were ≈0.13 and ≈0.41 for the Mg-4Zn-0.6Zr-0.4Sr and the Mg-4Zn-0.6Zr-1.6Sr, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Radioactivity determination of [sup 90]Y, [sup 90]Sr and [sup 89]Sr mixtures by spectral deconvolution

    Energy Technology Data Exchange (ETDEWEB)

    Grau Malonda, A. (Inst. de Investigacion Basica, CIEMAT, Madrid (Spain)); Rodriguez Barquero, L. (Inst. de Investigacion Basica, CIEMAT, Madrid (Spain)); Grau Carles, A. (Inst. de Investigacion Basica, CIEMAT, Madrid (Spain))

    1994-01-22

    The measurement of [sup 90]Y, [sup 90]Sr and [sup 89]Sr in environmental samples has received considerable attention since the advent of the nuclear era. These three radionuclides are pure beta-ray emitters and a nondestructive sample analysis procedure is not available. It is necessary to use complex radiochemical separation procedures to isolate these radionuclides prior to counting. The result is a significant delay between the sample treatment and the activity determination. A rapid analytical procedure is required to obtain the activity of these radionuclides and would appear to be an important goal. A deconvolution method has been applied to logarithmic spectra obtained with a liquid scintillation spectrometer. In a previous paper, this procedure was applied to samples in which [sup 90]Y and [sup 90]Sr were in equilibrium. Samples have been assessed in which [sup 90]Y activity was higher or lower than [sup 90]Sr activity, and medium and low activities were considered. Samples with count rates below background were analyzed, and the limits of detection of the procedure were determined. The effects of chemical quench and the different activity ratios were studied. It was shown that this treatment of the beta spectra is adequate and represents a rapid method of determining these radionuclides. (orig.)

  19. Temperature-dependent impedance spectroscopy of La0.8Sr0.2FeO3 nano-crystalline material

    Science.gov (United States)

    Kafa, C. A.; Triyono, D.; Laysandra, H.

    2017-04-01

    LaFeO3 is a material with perovskite structure which electrical properties frequently investigated. Research are done due to the exhibition of excellent gas sensing behavior through resistivity comparison from the p-type semiconductor. Sr doping on LaFeO3 or La1-xSrxFeO3 are able to improve the electrical conductivity through structural modification. Using Sr dopant concentration (x) of 0.2, La0.8Sr0.2FeO3 nano-crystal pellet was synthesized. The synthesis used sol-gel method, followed by gradual heat treatment and uniaxial compaction. XRD characterization shows that the structure of the sample is Orthorhombic Perovskite. Topography of the sample by SEM reveals grain and grain boundary existence with emerging agglomeration. The electrical properties of the material, as functions of temperature and frequency, were measured by Impedance Spectroscopy method using RLC meter, for temperatures of 303-373K. Through the Nyquist plot and Bode plot, the electrical conductivity of La0.8Sr0.2FeO3 is contributed by the grain and grain boundary. Finally, the electrical permittivities of La0.8Sr0.2FeO3 are increasing with temperature increase, with the highest achieved when measured at 1 kHz frequency.

  20. On the physical properties of Sr.sub.1-x./sub.Na.sub.x./sub.RuO.sub.3./sub. (x = 0 - 0.19)

    Czech Academy of Sciences Publication Activity Database

    Tomeš, P.; Knížek, Karel; Weidenkaff, A.; Hejtmánek, Jiří

    2010-01-01

    Roč. 12, č. 7 (2010), s. 1112-1120 ISSN 1293-2558 Institutional research plan: CEZ:AV0Z10100521 Keywords : perovskite SrRuO 3 * magnetism * heat capacity * weak localization Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.828, year: 2010

  1. Characterization of thin heteroepitaxial diamond films on Ir/SrTiO3 by X-ray diffraction and micro-Raman spectroscopy

    OpenAIRE

    Stritzker, Bernd

    1999-01-01

    Characterization of thin heteroepitaxial diamond films on Ir/SrTiO3 by X-ray diffraction and micro-Raman spectroscopy / H. Roll, M. Schreck, B. Stritzker. – In: Applied Diamond Conference/ Frontier Carbon Technology Joint Conference 1999 / ed. by: M. Yoshikawa ... - Tsukuba : Tsukuba Research Center, 1999. S. 73-781

  2. A preliminary study for the development of reference material using oyster for determination of (137)Cs, (90)Sr and plutonium isotopes.

    Science.gov (United States)

    Lee, Sang-Han; Oh, Jung-Suk; Lee, Jong-Man; Lee, Kyung-Bum; Park, Tae-Soon; Lee, Min-Kie; Kim, Seung-Hwan; Choi, Jong-Ki

    2016-03-01

    A new reference material for the determination of (137)Cs, (90)Sr and Pu isotopes ((238)Pu and (239,240)Pu) is being developed using dried oyster matrix by Korea Research Institute of Standards and Science (KRISS). The oyster was collected from Tongyoung harbour, southern part of Korea and the artificial radionuclides ((137)Cs, (90)Sr, (238)Pu and (239,240)Pu) were spiked into the material. After pretreatment and processing, the material was tested for homogeneity and massic activities were determined by measuring (137)Cs, (90)Sr, (238)Pu and (239,240)Pu. The reference value and extended uncertainty for those isotopes will be reported later. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Anomalously large measured thermoelectric power factor in Sr1−xLaxTiO3 thin films due to SrTiO3 substrate reduction

    NARCIS (Netherlands)

    Scullin, Matthew L.; Yu, Choongho; Huijben, Mark; Mukerjee, Subroto; Seidel, Jan; Zhang, Qian; Moore, Joel; Majumdar, Arun; Ramesh, R.

    2008-01-01

    We report the observation that thermoelectric thin films of La-doped SrTiO3 grown on SrTiO3 substrates yield anomalously high values of thermopower to give extraordinary values of power factor at 300 K. Thin films of Sr0.98La0.02TiO3, grown via pulsed laser deposition at low temperature and low

  4. SR1—a small RNA with two remarkably conserved functions

    Science.gov (United States)

    Gimpel, Matthias; Preis, Heike; Barth, Emanuel; Gramzow, Lydia; Brantl, Sabine

    2012-01-01

    SR1 is a dual-function sRNA that acts as a base-pairing regulatory RNA on the ahrC mRNA and as a peptide-encoding mRNA on the gapA operon. The SR1-encoded peptide SR1P binds GapA thereby stabilizing gapA mRNA. Under glycolytic conditions, SR1 transcription is repressed by CcpN and CcpA. A computer-based search identified 23 SR1 homologues in Bacillus, Geobacillus, Anoxybacillus and Brevibacillus species. All homologues share a high structural identity with Bacillus subtilis SR1, and the encoded SR1P peptides are highly similar. In the Bacillus cereus group, the sr1p region is present in triplicate or duplicate resulting in longer SR1 species. In all cases, sr1 expression is under control of CcpN, and transcriptional lacZ fusions of nine examined SR1 homologues were sensitive to glucose. Two homologues showed an additional glucose-independent repression by CcpN and an unknown factor. A total of 10 out of 11 tested SR1P homologues complemented a B. subtilis Δsr1 strain in their ability to stabilize gapA mRNA, but only five of them bound GapA tightly. In vitro binding assays with six SR1/ahrC pairs suggest that—despite divergent primary sequences—the base-pairing function is also preserved. In summary, SR1 is an sRNA with two functions that have been conserved over ≈1 billion years. PMID:23034808

  5. Evidence for SrHo2O4 and SrDy2O4 as model J1-J2 zigzag chain materials

    DEFF Research Database (Denmark)

    Fennell, A.; Pomjakushin, V. Y.; Uldry, A.

    2014-01-01

    Neutron diffraction and inelastic spectroscopy is used to characterize the magnetic Hamiltonian of SrHo2O4 and SrDy2O4. Through a detailed computation of the crystal-field levels we find site-dependent anisotropic single-ion magnetism in both materials, and diffraction measurements show the prese......Neutron diffraction and inelastic spectroscopy is used to characterize the magnetic Hamiltonian of SrHo2O4 and SrDy2O4. Through a detailed computation of the crystal-field levels we find site-dependent anisotropic single-ion magnetism in both materials, and diffraction measurements show...

  6. Geochemical tracing of As pollution in the Orbiel Valley (southern France): 87Sr/86Sr as a tracer of the anthropogenic arsenic in surface and groundwater.

    Science.gov (United States)

    Khaska, Mahmoud; Le Gal La Salle, Corinnne; Lancelot, Joël; Verdoux, Patrick; Boutin, René

    2014-05-01

    The environmental impacts of arsenic mining activities and their effects on ecosystem and human health are observed in many stream waters and groundwater. The aim of this study is to identify the origin of As content in a mining environment using Sr isotopes. At the Salsigne gold mine, before the closure in 2004, high arsenic content has been observed in surface water and groundwater in the Orbiel valley. At the site, immobilization of As, in As rich leachate, is carried out by adding CaO. High contrast in 87Sr/86Sr between Arsenic rich minerals associated with Variscan metamorphic rocks (0.714888-0.718835), together with rich As waste water (0.713463-715477), and the CaO (0.707593) allows as to trace the origin of anthropogenic As. In 2012, Orbiel stream waters were sampled monthly upstream and downstream from the ancient ore processing site and once after an important rainy event (117mm). The upstream valley samples showed low and relatively constant As content with natural regional background of 3.6 and 5.6 μg/L. The rainy event induced only a slight increase in the As content up to 6.3 μg/L. High 87Sr/86Sr ratios suggested an influence of radiogenic Sr issued from the Variscan metamorphic basement. Downstream from the area, the As content was at least10 time as high. In the wet season, stream water As content clearly increased to 13.9-24 μg/L, reaching 120.5 μg/L during the rainy event. Associated 87Sr/86Sr ratio showed to be less radiogenic (0.712276-0.714002). The anti correlation observed between As and 87Sr/86Sr suggest that As issued from a natural origin is characterised by a high 87Sr/86Sr compared to As derived from the CaO treatement used on site and characterized by a low 87Sr/86Sr ratio. During the dry season, increase in As content was observed reaching 110 μg/L. These highlights the contribution of alluvial groundwater to base flow, probably associated with As reach leachate from the site. Contribution from the alluvial aquifer is confirmed by

  7. Pulse height distribution of signals produced by exposing a thin GEM chamber to beta rays from an Sr-90 source

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, B. J.; Ha, Y. J.; Hahn, C. H. [Changwon National University, Changwon (Korea, Republic of); Park, S. T. [University of Texas at Arlington, Texas (United States); Yi, C. Y. [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of); Lee, R. [Ewha Womans University, Seoul (Korea, Republic of)

    2014-05-15

    Researchers at Changwon National University's Radiation Detector Development Laboratory(RDD) fabricated a single-channel double-GEM (gas electron multiplier) chamber and measured the pulse height distribution of signals produced by exposing the chamber to an Sr-90 source provided by the Korea Research Institute of Standards and Science(KRISS). A beta-ray electron incident on the GEM chamber ionizes gaseous molecules in the drift region of the chamber by means of electromagnetic interactions. After the leased electrons are amplified by electron avalanches in the GEM stages, the multiplied electrons go from the lowest GEM foil toward the anode of the chamber and induce one signal pulse, corresponding to the incident electron, on the readout pad. The charge signal distribution measured during Sr-90 radioactive source irradiation was compared with the simulation done by using a Landau probability distribution. The energy loss distribution of beta-ray electrons, which deposited part of their energy in a thin GEM chamber while traversing gases within the drift region of that chamber, was in good agreement with the calculation of the Landau probability distribution. The pulse height distributions for energy losses of beta-ray electrons incident on the chamber due to Sr-90 disintegrations were observed in order to select a suitable gas mixture for the chamber. The ratios of the Ar/CO{sub 2} gas were 75/25, 80/20, 85/15, and 90/10.

  8. Morphological, thermal and optical studies of jute-reinforced PbSrCaCuO-polypropylene composite

    Science.gov (United States)

    Jacob, Reenu; Isac, Jayakumari

    2016-11-01

    New research with modern technologies has always grabbed substantial attention. Conservation of raw materials like natural fibers has helped composite world to explore eco-friendly components. The aim of this paper is to study the potential of jute fiber-reinforced ceramic polymers. Alkali-treated jute fiber has been incorporated in a polypropylene ceramic matrix at different volume fractions. The morphological, thermal and optical studies of jute-reinforced ceramic Pb2Sr2CaCu2O9 (PbSrCaCuO) are studied. Morphological results evidently demonstrate that when the polypropylene ceramic matrix is reinforced with jute fiber, interfacial interaction between the varying proportions of the jute fiber and ceramic composite takes place. TGA and DSC results confirm the enhancement in the thermal stability of ceramic composites reinforced with jute fiber. The UV analysis of the composite gives a good quality measure on the optical properties of the new composite prepared.

  9. Interim main report of the safety assessment SR-Can

    Energy Technology Data Exchange (ETDEWEB)

    Hedin, Allan (ed.) [and others

    2004-08-01

    This document is an interim report on the safety assessment SR-Can (SR in the acronym stands for Safety Report and Can is short for canister). The final SR-Can report will support SKB's application to build an Encapsulation plant for spent nuclear fuel and is to be produced in 2006. The purpose of the present interim report is to demonstrate the methodology for safety assessment so that it can be reviewed before it is used in a license application. The assessment relates to the KBS-3 disposal concept in which copper canisters with a cast iron insert containing spent nuclear fuel are surrounded by bentonite clay and deposited at approximately 500 m depth in saturated, granitic rock. Preliminary data from the Forsmark site, presently being investigated by SKB as one of the candidate for a KBS-3 repository are used to some extent as examples. However, the collected data are yet too sparse to allow an evaluation of safety for this site. An important aim of this report is to demonstrate the proper handling of requirements on the safety assessment in applicable regulations. Therefore, regulations issued by the Swedish Nuclear Power Inspectorate and the Swedish Radiation Protection Authority are duplicated in an Appendix. The principal acceptance criterion requires that 'the annual risk of harmful effects after closure does not exceed 10{sup -6} for a representative individual in the group exposed to the greatest risk'. 'Harmful effects' refer to cancer and hereditary effects. Following the introductory chapter 1, this report outlines the methodology for the SR-Can assessment in chapter 2, and presents in chapters 3, 4 and 5 the initial state of the system and the plans and methods for handling external influences and internal processes, respectively. Function indicators are introduced in chapter 6 and a preliminary evaluation of these is given in chapter 7. The material presented in the first seven chapters is utilised in the scenario selection

  10. New aragonite 87Sr/86Sr records of Mesozoic ammonoids and approach to the problem of N, O, C and Sr isotope cycles in the evolution of the Earth

    Science.gov (United States)

    Zakharov, Yuri D.; Dril, Sergei I.; Shigeta, Yasunari; Popov, Alexander M.; Baraboshkin, Eugenij Y.; Michailova, Irina A.; Safronov, Peter P.

    2018-02-01

    New Sr isotope data from well-preserved aragonite ammonoid shell material from the Mesozoic are compared with that from a living Nautilus shell. The prominent negative Sr isotope excursions known from the Middle Permian, Jurassic and Cretaceous probably have their origins in intensive plate tectonic activity, followed by enhanced hydrothermal activity at the mid-ocean ridges (mantle volcanism) which supplied low radiogenic Sr to seawater. The maximum positive (radiogenic) shift in the lower Mesozoic Sr isotope curve (Lower Triassic peak) was likely caused by a significant expansion of dry land surfaces (Dabie-Sulu Triassic orogeny) and their intensive silicate weathering in conditions of extreme warming and aridity in the very end of the Smithian, followed by warm and humid conditions in the late Spathian, which apparently resulted in a significant oceanic input of radiogenic Sr through riverine flux. The comparatively high 87Sr/86Sr ratio obtained from the living Nautilus shell is probably a function of both the Alpine orogeny, which was accompanied by significant continental weathering and input of radiogenic Sr to the oceans, and the weakening of mantle volcanism.

  11. Synthesis and luminescent characterization of Sr2SiO4:Eu2+ nanopowders.

    Science.gov (United States)

    Lee, Jun Seong; Kim, Young Jin

    2012-11-01

    Sr2SiO4:Eu2+ nanopowders were synthesized by a co-precipitation method using strontium nitrate, 3-aminopropyltriethoxysilane (APTES), europium nitrate hydrate, and a flux (NH4Cl). The structural and luminescent properties strongly depended on the firing conditions, the amount of APTES, and the flux content. Alpha'-Sr2SiO4 was produced as a dominant phase after firing as-prepared powders without a flux, whereas the addition of NH4Cl caused beta-Sr2SiO4 to be the primary phase. At a small amount of APTES, the as-prepared powders that were fired with NH4Cl consisted of the beta-Sr2SiO4, Sr3SiO5, and un-reacted SrO phases. Then, the phase transformation from SrO and Sr3SiO5 to beta-Sr2SiO4 gradually proceeded as the amount of APTES was increased, leading to the pure beta-Sr2SiO4 phase at 0.5 M APTES. The phase transition and photoluminescence properties strongly relied on the amount of NH4Cl. The preparation condition of 0.5 M APTES and 2 wt% NH4Cl was the optimum condition to obtain the pure beta-Sr2SiO4:Eu2+ phase and the most excellent PL intensity.

  12. Structural Transition in SrZnO Laser Pulse Deposited Alloy

    Directory of Open Access Journals (Sweden)

    Albrithen H. A.

    2017-03-01

    Full Text Available We have discovered a structural transition for the SrZnO alloy films from a wurtzite to a rock-salt structure, leading to a reduction in the (112̲0/(0001 surface energy ratio. The films were grown by pulsed laser deposition using different SrO ratios, x. We have revealed that growth at a higher temperature, 750°C, resulted in a sharp 0002 peak at a low SrO content (5%, whereas growth at a higher SrO content (10% resulted in a non-crystalline film with minute crystallites with a (112̲0 orientation. Generally the crystallinity decreased as the SrO content increased. No results obtained for the crystalline films showed any orientation of significant peaks besides the peak attributed to the (0001 plane, suggesting epitaxial growth. Optical measurements showed difference in transmission widows of alloys with different SrO percentage, and this was correlated to SrO influence on growth mode as indicated by scanning electron imaging. The studied SrZnO films, with SrO/(SrO + ZnO ≤ 0.25, were grown by pulsed laser deposition using different SrO ratios, x. The effects of temperature and oxygen pressure during growth on the films’ structural properties were investigated. XRD results indicate that the film crystallinity was improved as the temperature and O2 pressure increased up to 650°C and 0.5 Torr, respectively.

  13. Integrated Sr isotope variations and global environmental changes through the Late Permian to early Late Triassic

    Science.gov (United States)

    Song, Haijun; Wignall, Paul B.; Tong, Jinnan; Song, Huyue; Chen, Jing; Chu, Daoliang; Tian, Li; Luo, Mao; Zong, Keqing; Chen, Yanlong; Lai, Xulong; Zhang, Kexin; Wang, Hongmei

    2015-08-01

    New 87Sr/86Sr data based on 127 well-preserved and well-dated conodont samples from South China were measured using a new technique (LA-MC-ICPMS) based on single conodont albid crown analysis. These reveal a spectacular climb in seawater 87Sr/86Sr ratios during the Early Triassic that was the most rapid of the Phanerozoic. The rapid increase began in Bed 25 of the Meishan section (GSSP of the Permian-Triassic boundary, PTB), and coincided closely with the latest Permian extinction. Modeling results indicate that the accelerated rise of 87Sr/86Sr ratios can be ascribed to a rapid increase (>2.8×) of riverine flux of Sr caused by intensified weathering. This phenomenon could in turn be related to an intensification of warming-driven runoff and vegetation die-off. Continued rise of 87Sr/86Sr ratios in the Early Triassic indicates that continental weathering rates were enhanced >1.9 times compared to those of the Late Permian. Continental weathering rates began to decline in the middle-late Spathian, which may have played a role in the decrease of oceanic anoxia and recovery of marine benthos. The 87Sr/86Sr values decline gradually into the Middle Triassic to an equilibrium values around 1.2 times those of the Late Permian level, suggesting that vegetation coverage did not attain pre-extinction levels thereby allowing higher runoff.

  14. Development of a 3D-Printed Collimated 90Sr Beta Source

    Science.gov (United States)

    Daniel, Byron; NuDot Collaboration

    2017-09-01

    Collimated beta particle sources based on 90Sr are common calibration sources for atomic decay detector research and development. Due to the short attenuation length of beta particles in matter, the exact geometry of a collimator can drastically change the rate and energy of beta particles exiting the source. 3D printing allows for the quick and easy prototyping of collimators with custom geometries. I will describe the development of a collimator that interfaces directly to a quartz cuvette for the characterization of liquid scintillator cocktails. Future work will include developing a source for the NuDot detector which aims to reconstruct MeV electrons using the separation of Cherenkov and scintillation light. MIT Summer Research Program.

  15. Epitaxial growth and electronic structure of oxyhydride SrVO{sub 2}H thin films

    Energy Technology Data Exchange (ETDEWEB)

    Katayama, Tsukasa; Chikamatsu, Akira, E-mail: chikamatsu@chem.s.u-tokyo.ac.jp; Yamada, Keisuke; Onozuka, Tomoya [Department of Chemistry, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); Shigematsu, Kei [Kanagawa Academy of Science and Technology, Kawasaki, Kanagawa 213-0012 (Japan); Minohara, Makoto; Kumigashira, Hiroshi [Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801 (Japan); Ikenaga, Eiji [Japan Synchrotron Radiation Research Institute (JASRI)/SPring-8, Mikazuki-cho, Hyogo 679-5198 (Japan); Hasegawa, Tetsuya [Department of Chemistry, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); Kanagawa Academy of Science and Technology, Kawasaki, Kanagawa 213-0012 (Japan)

    2016-08-28

    Oxyhydride SrVO{sub 2}H epitaxial thin films were fabricated on SrTiO{sub 3} substrates via topotactic hydridation of oxide SrVO{sub 3} films using CaH{sub 2}. Structural and composition analyses suggested that the SrVO{sub 2}H film possessed one-dimensionally ordered V-H{sup −}-V bonds along the out-of-plane direction. The synthesis temperature could be lowered by reducing the film thickness, and the SrVO{sub 2}H film was reversible to SrVO{sub 3} by oxidation through annealing in air. Photoemission and X-ray absorption spectroscopy measurements revealed the V{sup 3+} valence state in the SrVO{sub 2}H film, indicating that the hydrogen existed as hydride. Furthermore, the electronic density of states was highly suppressed at the Fermi energy, consistent with the prediction that tetragonal distortion induces metal to insulation transition.

  16. Provenancing fish in freshwaters of the Alpine Foreland using Sr/Ca and 87Sr/86Sr ratios in otoliths and otolith shape parameters

    Directory of Open Access Journals (Sweden)

    Johannes Oehm

    2015-12-01

    Although the studied freshwaters were located only in a 50 km range around lake Chiemsee on a similar geological background, differences in water chemistry, fish otolith chemistry and shape were identified. Species specific differences in reflection of the Sr/Ca ratio of a specific water body were detected. Microchemical and morphological otoliths analyses complemented each other and allowed assigning fish to specific groups of waters of origin. This information provides an important basis for the further application of otolith chemistry and shape analysis in the Alpine foreland for a diverse range of ecological questions.

  17. Atomic structure calculations and identification of EUV and SXR spectral lines in Sr XXX

    Science.gov (United States)

    Goyal, Arun; Khatri, Indu; Aggarwal, Sunny; Singh, A. K.; Mohan, Man

    2015-08-01

    We report an extensive theoretical study of atomic data for Sr XXX in a wide range with L-shell electron excitations to the M-shell. We have calculated energy levels, wave-function compositions and lifetimes for lowest 113 fine structure levels and wavelengths of an extreme Ultraviolet (EUV) and soft X-ray (SXR) transitions. We have employed multi-configuration Dirac Fock method (MCDF) approach within the framework of Dirac-Coulomb Hamiltonian including quantum electrodynamics (QED) and Breit corrections. We have also presented the radiative data for electric and magnetic dipole (E1, M1) and quadrupole (E2, M2) transitions from the ground state. We have made comparisons with available energy levels compiled by NIST and achieve good agreement. But due to inadequate data in the literature, analogous relativistic distorted wave calculations have also been performed using flexible atomic code (FAC) to assess the reliability and accuracy of our results. Additionally, we have provided new atomic data for Sr XXX which is not published elsewhere in the literature and we believe that our results may be beneficial in fusion plasma research and astrophysical investigations and applications.

  18. Band gap engineering via electrostatic chemical strain in cation ordered LaSrAlO4

    Science.gov (United States)

    Balachandran, Prasanna V.; Rondinelli, James M.

    2014-03-01

    In this work, we employ density functional theory to examine a novel design route that employs A-site cation ordering to engineer the band gaps of (A,A')BO4 Ruddlesden-Popper (RP) oxides. Using LaSrAlO4 as a model material, we show that the band gap is highly sensitive to the A-site cation ordering ranging from 3-4.5 eV. When the [AlO2]-1 layers are interleaved between two chemically equivalent [LaO]1+ or [SrO]0+ layers, we obtain the smallest band gap with a reduction of ~1 eV determined from the Heyd, Scuseria, and Ernzerhof (HSE) hybrid exchange-correlation functional. We relate the observed band gap reduction to the local bond distortions arising from electrostatic chemical strain induced changes to the O 2 p and La 5 d states in the valence and conduction bands, respectively. The project was supported by The Defense Advanced Research Projects Agency (grant no. N66001-12-4224). The views, opinions, and/or findings reported here are solely those of the authors and do not represent official views of DARPA or DOD.

  19. Spin dynamics in the antiferromagnetic phases of the Dirac metals AMnBi(A = Sr, Ca)

    Science.gov (United States)

    Rahn, Marein; Princep, Andrew; Piovano, Andrea; Kulda, Jiri; Guo, Yan Feng; Shi, You Guo; Boothroyd, Andrew

    The square Bi layers in AMnBi(A = Sr, Ca) host strongly spin-orbit coupled bands that form highly anisotropic Dirac points. We have mapped the dispersion of Mn spin fluctuations in these materials by triple-axis neutron spectroscopy. The spectra show pronounced spin gaps of 10.(2) meV (Sr) and 8.(8) meV (Ca) and extend to maximum energy transfers of 61-63 meV. For each material, reciprocal space maps of the magnon spectral weight were recorded for both in-plane and out-of-plane momentum transfer. The observed spectra can be accurately reproduced by a simple linear spin-wave model. Detailed global '?fits of the full magnon dispersion allow tight constraints on the magnitude of in-plane and inter-layer exchange parameters as well as on the magnetocrystalline anisotropy constant. We '?find no evidence that the magnetic ground state of these materials is coupled to the topology of the Bi 6px,ybands. This work was supported by the U.K. Engineering and Physical Sciences Research Council (Grant No. EP/J017124/1). MCR is grateful to the Oxford University Clarendon Fund for provision of a scholarship.

  20. 87Sr/88Sr a useful tool for the identification of geographic origin of Styrian pumpkin seed oils?

    Science.gov (United States)

    Meisel, T.; Bandoniene, D.; Zettl, D.; Maneiko, M.; Horschinegg, M.

    2012-04-01

    The authenticity and the geographic origin of Styrian pumpkin seed oil (PGI) a regional specialty needs to be protected, but the current specification of this high priced product does not include the proof of origin through analytical tools. As it turns out, this and many other products within the Protected Geographical Status (PGS) framework of the European Union, cannot be protected from fraud without forensic tools. In previous studies we were able to demonstrate, that distribution and content of trace elements in particular the rare earth elements, are useful parameters to discriminate Austrian from non-Austrian pumpkin seed oils and seeds. Unlike stable isotopes ratios (C and H), the trace element patterns are not influenced by changes in weather conditions and temperature during growing and harvesting cycle. Though the study of the distribution of element traces can be used not only for the identification of the geographic origin with very useful PLS and PCA models but also can identify fraud through mixing with other oils, this method need to be validated by other means. Radiogenic isotopes, in particular the 87Sr/86Sr isotope amount ratio has been successfully applied to food and other products for forensic studies. In this study we determined the 87Sr/86Sr isotope amount ratio in pumpkin seed oils extracted from seeds of known geographic origin from Austria, Russia and China, as these are the largest producers, to see if significant differences occur and if they can be used as a forensic tool. Although the total area of the Russian and the Chinese crop fields are magnitudes larger than the ones from Austria, it turns out that the variance of the Austrian 87Sr/86Sr data is much larger than that from other sources. Reasons are the large diversity of the Austrian geology (pre-varsican, alpine to sub-recent ages of the underlying bedrock of the soils can be found), the small farm sizes and the small scale production. In Russia large farms are situated on

  1. Minimal model for calcium alternans due to SR release refractoriness

    Science.gov (United States)

    Cantalapiedra, Inma R.; Alvarez-Lacalle, Enrique; Peñaranda, Angelina; Echebarria, Blas

    2017-09-01

    In the heart, rapid pacing rates may induce alternations in the strength of cardiac contraction, termed pulsus alternans. Often, this is due to an instability in the dynamics of the intracellular calcium concentration, whose transients become larger and smaller at consecutive beats. This alternation has been linked experimentally and theoretically to two different mechanisms: an instability due to (1) a strong dependence of calcium release on sarcoplasmic reticulum (SR) load, together with a slow calcium reuptake into the SR or (2) to SR release refractoriness, due to a slow recovery of the ryanodine receptors (RyR2) from inactivation. The relationship between calcium alternans and refractoriness of the RyR2 has been more elusive than the corresponding SR Ca load mechanism. To study the former, we reduce a general calcium model, which mimics the deterministic evolution of a calcium release unit, to its most basic elements. We show that calcium alternans can be understood using a simple nonlinear equation for calcium concentration at the dyadic space, coupled to a relaxation equation for the number of recovered RyR2s. Depending on the number of RyR2s that are recovered at the beginning of a stimulation, the increase in calcium concentration may pass, or not, over an excitability threshold that limits the occurrence of a large calcium transient. When the recovery of the RyR2 is slow, this produces naturally a period doubling bifurcation, resulting in calcium alternans. We then study the effects of inactivation, calcium diffusion, and release conductance for the onset of alternans. We find that the development of alternans requires a well-defined value of diffusion while it is less sensitive to the values of inactivation or release conductance.

  2. Fully Cationized Gold Clusters: Synthesis of Au25(SR+)18.

    Science.gov (United States)

    Ishida, Yohei; Narita, Kunihiro; Yonezawa, Tetsu; Whetten, Robert L

    2016-10-06

    Although many thiolate-protected Au clusters with different numbers of Au atoms and a variety of thiolate ligands have been synthesized, to date there has been no report of a fully cationized Au cluster protected with cationic thiolates. Herein, we report the synthesis of the first member of a new series of thiolate-protected Au cluster molecules: a fully cationized Au 25 (SR + ) 18 cluster.

  3. SR90, strontium shaped-charge critical ionization velocity experiment

    Science.gov (United States)

    Wescott, Eugene M.; Stenbaek-Nielsen, Hans; Swift, Daniel W.; Valenzuela, Arnoldo; Rees, David

    1990-01-01

    In May 1986 an experiment was performed to test Alfven's critical ionization velocity (CIV) effect in free space, using the first high explosive shaped charge with a conical liner of strontium metal. The release, made at 540 km altitude at dawn twilight, was aimed at 48 deg to B. The background electron density was 1.5 x 10(exp 4) cu cm. A faint field-aligned Sr(+) ion streak with tip velocity of 2.6 km/s was observed from two optical sites. Using two calibration methods, it was calculated that between 4.5 x 10(exp 20) and 2 x 10(exp 21) ions were visible. An ionization time constant of 1920 s was calculated for Sr from the solar UV spectrum and ionization cross section which combined with a computer simulation of the injection predicts 1.7 x 10(exp 21) solar UV ions in the low-velocity part of the ion streak. Thus all the observed ions are from solar UV ionization of the slow (less than critical) velocity portion of the neutral jet. The observed neutral Sr velocity distribution and computer simulations indicate that 2 x 10(exp 21) solar UV ions would have been created from the fast (greater than critical) part of the jet. They would have been more diffuse, and were not observed. Using this fact it was estimated that any CIV ions created were less than 10(exp 21). It was concluded that future Sr CIV free space experiments should be conducted below the UV shadow height and in much larger background plasma density.

  4. High magnetic field {mu}SR instrument scientific case

    Energy Technology Data Exchange (ETDEWEB)

    Amato, A

    2005-10-15

    In order to gain more insight into the specific behavior of materials, it is often necessary to perform measurements as a function of different external parameters. Despite its high sensitivity to internal fields, this simple observation also applies for the {mu}SR technique. The most common parameter which can be tuned during an experiment is the sample temperature. By using a range of cryostats, temperatures between 0.02 and 900 K can be covered at the PSI {mu}SR Facility. On the other hand, and by using high-energy muons, pressures as high as 10'000 bars can nowadays be reached during {mu}SR experiments. As will be demonstrated in the following Sections, the magnetic field is an additional external parameter playing a fundamental role when studying the ground state properties of materials in condensed matter physics and chemistry. However, the availability of high magnetic fields for {mu}SR experiments is still rather limited. Hence, if on one hand the high value of the gyromagnetic ratio of the muon provides the high magnetic sensitivity of the method, on the other hand it can lead to very high muon-spin precession frequencies when performing measurements in applied fields (the muon-spin precession frequency in a field of 1 Tesla s 135.5 MHz). Consequently, the use of ultra-fast detectors and electronics is mandatory when measuring in magnetic fields exceeding 1 Tesla. If such fields are very intense when compared to the Earth magnetic field < 10{sup -4} Tesla), the energy associated with them is still modest in view of the thermal energy. Hence, the Zeeman energy splitting of a free electron in a magnetic field of 1 Tesla corresponds to a thermal energy as low as 0.67 Kelvin. It is worth mentioning that nowadays magnetic fields of the order of 10 to 15 Tesla are quite common in condensed matter laboratories and have opened up vast new exciting experimental possibilities. (author)

  5. Overlearned responses hinder S-R binding.

    Science.gov (United States)

    Moeller, Birte; Frings, Christian

    2017-01-01

    Two mechanisms that are important for human action control are the integration of individual action plans (see Hommel, Müsseler, Aschersleben, & Prinz, 2001) and the automatization of overlearned actions to familiar stimuli (see Logan, 1988). In the present study, we analyzed the influence of automatization on action plan integration. Integration with pronunciation responses were compared for response incompatible word and nonword stimuli. Stimulus-response binding effects were observed for nonwords. In contrast, words that automatically triggered an overlearned pronunciation response were not integrated with pronunciation of a different word. That is, automatized response retrieval hindered binding effects regarding the retrieving stimulus and a new response. The results are a first indication of the way that binding and learning processes interact, and might also be a first step to understanding the more complex interdependency of the processes responsible for stimulus-response binding in action control and stimulus-response associations in learning research. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  6. SR-Site groundwater flow modelling methodology, setup and results

    Energy Technology Data Exchange (ETDEWEB)

    Selroos, Jan-Olof (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)); Follin, Sven (SF GeoLogic AB, Taeby (Sweden))

    2010-12-15

    As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken three groundwater flow modelling studies. These are performed within the SR-Site project and represent time periods with different climate conditions. The simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. Three time periods are addressed; the Excavation and operational phases, the Initial period of temperate climate after closure, and the Remaining part of the reference glacial cycle. The present report is a synthesis of the background reports describing the modelling methodology, setup, and results. It is the primary reference for the conclusions drawn in a SR-Site specific context concerning groundwater flow during the three climate periods. These conclusions are not necessarily provided explicitly in the background reports, but are based on the results provided in these reports. The main results and comparisons presented in the present report are summarised in the SR-Site Main report.

  7. Blackbody-radiation shift in the Sr optical atomic clock

    Science.gov (United States)

    Safronova, M. S.; Porsev, S. G.; Safronova, U. I.; Kozlov, M. G.; Clark, Charles W.

    2013-01-01

    We evaluated the static and dynamic polarizabilities of the 5s21S0 and 5s5p3P0o states of Sr using the high-precision relativistic configuration interaction combined with the all-order method. Our calculation explains the discrepancy between the recent experimental 5s21S0-5s5p3P0o dc Stark shift measurement Δα=247.379(7) [Middelmann , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.109.263004 109, 263004 (2012)] and the earlier theoretical result of 261(4) a.u. [Porsev and Derevianko, Phys. Rev. APLRAAN1050-294710.1103/PhysRevA.74.020502 74, 020502(R) (2006)]. Our present value of 247.5 a.u. is in excellent agreement with the experimental result. We also evaluated the dynamic correction to the BBR shift with 1% uncertainty; -0.1492(16) Hz. The dynamic correction to the BBR shift is unusually large in the case of Sr (7%) and it enters significantly into the uncertainty budget of the Sr optical lattice clock. We suggest future experiments that could further reduce the present uncertainties.

  8. Blackbody radiation shift in the Sr optical atomic clock

    Science.gov (United States)

    Porsev, Sergey; Safronova, Marianna; Safronova, Ul'yana; Kozlov, Mikhail; Clark, Charles

    2013-05-01

    We evaluated the static and dynamic polarizabilities of the 5s21S0 and 5 s 5 p 3P0o states of Sr using the high-precision relativistic configuration interaction + all-order method. Our calculation explains the discrepancy between the recent experimental 5s21S0 - 5 s 5 p3P0o dc Stark shift measurement Δα = 247 . 379 (7) [Middelmann et al., Phys. Rev. Lett. 109, 263004 (2012)] and the earlier theoretical result of 261(4) a.u. [Porsev and Derevianko, Phys. Rev. A 74, 020502R (2006)]. Our present value of 247.5 a.u. is in excellent agreement with the experimental result. We also evaluated the dynamic correction to the BBR shift with 1% uncertainty; -0.1492(16) Hz. The dynamic correction to the BBR shift is unusually large in the case of Sr (7%) and it enters significantly into the uncertainty budget of the Sr optical lattice clock. We suggest future experiments that could further reduce the present uncertainties. NIST, ONR, NSF, RFBR

  9. Protection against retrovirus pathogenesis by SR protein inhibitors.

    Directory of Open Access Journals (Sweden)

    Anne Keriel

    Full Text Available Indole derivatives compounds (IDC are a new class of splicing inhibitors that have a selective action on exonic splicing enhancers (ESE-dependent activity of individual serine-arginine-rich (SR proteins. Some of these molecules have been shown to compromise assembly of HIV infectious particles in cell cultures by interfering with the activity of the SR protein SF2/ASF and by subsequently suppressing production of splicing-dependent retroviral accessory proteins. For all replication-competent retroviruses, a limiting requirement for infection and pathogenesis is the expression of the envelope glycoprotein which strictly depends on the host splicing machinery. Here, we have evaluated the efficiency of IDC on an animal model of retroviral pathogenesis using a fully replication-competent retrovirus. In this model, all newborn mice infected with a fully replicative murine leukemia virus (MLV develop erythroleukemia within 6 to 8 weeks of age. We tested several IDC for their ability to interfere ex vivo with MLV splicing and virus spreading as well as for their protective effect in vivo. We show here that two of these IDC, IDC13 and IDC78, selectively altered splicing-dependent production of the retroviral envelope gene, thus inhibiting early viral replication in vivo, sufficiently to protect mice from MLV-induced pathogenesis. The apparent specificity and clinical safety observed here for both IDC13 and IDC78 strongly support further assessment of inhibitors of SR protein splicing factors as a new class of antiretroviral therapeutic agents.

  10. Preparation of highly stable zeolite-alginate foam composite for strontium(90Sr) removal from seawater and evaluation of Sr adsorption performance.

    Science.gov (United States)

    Hong, Hye-Jin; Kim, Byoung-Gyu; Ryu, Jungho; Park, In-Su; Chung, Kang-Sup; Lee, Sang Moon; Lee, Jin-Bae; Jeong, Hyeon Su; Kim, Hyunchul; Ryu, Taegong

    2018-01-01

    Alginate bead is a promising strontium (Sr) adsorbent in seawater, but highly concentrated Na ions caused over-swelling and damaged the hydrogel bead. To improve the mechanical stability of alginate bead, flexible foam-type zeolite-alginate composite was synthesized and Sr adsorption performance was evaluated in seawater; 1-10% zeolite immobilized alginate foams were prepared by freeze-dry technique. Immobilization of zeolite into alginate foam converted macro-pores to meso-pores which lead to more compact structure. It resulted in less swollen composite in seawater medium and exhibited highly improved mechanical stability compared with alginate bead. Besides, Sr adsorption efficiency and selectivity were enhanced by immobilization of zeolite in alginate foam due to the increase of Sr binding sites (zeolite). In particular, Sr selectivity against Na was highly improved. The 10% zeolite-alginate foam exhibited a higher log K d of 3.3, while the pure alginate foam exhibited 2.7 in the presence of 0.1 M Na. Finally, in the real seawater, the 10% zeolite-alginate foam exhibited 1.5 times higher Sr adsorption efficiency than the pure alginate foam. This result reveals that zeolite-alginate foam composite is appropriate material for Sr removal in seawater due to its swelling resistance as well as improved Sr adsorption performance in complex media. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Oxygen-driven competition between low-dimensional structures of Sr3CoMO6 and Sr3CoMO7-δ with M = Ru, Ir.

    Science.gov (United States)

    Mikhailova, Daria; Reichel, Phillip; Tsirlin, Alexander A; Abakumov, Artem M; Senyshyn, Anatoliy; Mogare, Kailash M; Schmidt, Marcus; Kuo, Chang-Yang; Pao, Chin-Wen; Pi, Tun-Wen; Lee, Jyh-Fu; Hu, Zhiwei; Tjeng, Liu Hao

    2014-10-07

    We have realized a reversible structure transformation of one-dimensional 1D K4CdCl6-type Sr3CoMO6 with the Co(2+)/M(4+) cation ordering into the two-dimensional 2D double layered Ruddlesden-Popper structure Sr3CoMO7-δ with a random distribution of Co and M (with M = Ru, Ir) upon increasing the partial oxygen pressure. The combined soft and hard X-ray absorption spectroscopy studies show that under transformation, Co and M cations were oxidized to Co(3+) and M(5+). During oxidation, high-spin Co(2+) in Sr3CoMO6 first transforms into high-spin Co(3+) in oxygen-deficient Sr3CoMO7-δ, and then further transforms into low-spin Co(3+) in fully oxidized Sr3CoMO7 upon further increasing the partial pressure of oxygen. The 1D Sr3CoMO6 compound is magnetically ordered at low temperatures with the magnetic moments lying along the c-axis. Their alignment is parallel for Sr3CoRuO6 and antiparallel for Sr3CoIrO6. The 2D compounds reveal a spin-glass-like behavior related to the random distribution of magnetic cations in the structure.

  12. PDRD (SR13046) TRITIUM PRODUCTION FINAL REPORT

    Energy Technology Data Exchange (ETDEWEB)

    Smith, P.; Sheetz, S.

    2013-09-30

    Utilizing the results of Texas A&M University (TAMU) senior design projects on tritium production in four different small modular reactors (SMR), the Savannah River National Laboratory’s (SRNL) developed an optimization model evaluating tritium production versus uranium utilization under a FY2013 plant directed research development (PDRD) project. The model is a tool that can evaluate varying scenarios and various reactor designs to maximize the production of tritium per unit of unobligated United States (US) origin uranium that is in limited supply. The primary module in the model compares the consumption of uranium for various production reactors against the base case of Watts Bar I running a nominal load of 1,696 tritium producing burnable absorber rods (TPBARs) with an average refueling of 41,000 kg low enriched uranium (LEU) on an 18 month cycle. After inputting an initial year, starting inventory of unobligated uranium and tritium production forecast, the model will compare and contrast the depletion rate of the LEU between the entered alternatives. This is an annual tritium production rate of approximately 0.059 grams of tritium per kilogram of LEU (g-T/kg-LEU). To date, the Nuclear Regulatory Commission (NRC) license has not been amended to accept a full load of TPBARs so the nominal tritium production has not yet been achieved. The alternatives currently loaded into the model include the three light water SMRs evaluated in TAMU senior projects including, mPower, Holtec and NuScale designs. Initial evaluations of tritium production in light water reactor (LWR) based SMRs using optimized loads TPBARs is on the order 0.02-0.06 grams of tritium per kilogram of LEU used. The TAMU students also chose to model tritium production in the GE-Hitachi SPRISM, a pooltype sodium fast reactor (SFR) utilizing a modified TPBAR type target. The team was unable to complete their project so no data is available. In order to include results from a fast reactor, the SRNL

  13. Comparing Pt/SrTiO3 to Rh/SrTiO3 for hydrogen photocatalytic production from ethanol

    KAUST Repository

    Wahab, A. K.

    2013-08-13

    Photocatalytic hydrogen production from ethanol as an example of biofuel is studied over 0.5 wt% Rh/SrTiO3 and 0.5 wt% Pt/SrTiO3 perovskite materials. The rate of hydrogen production, rH2, over Pt/SrTiO3 is found to be far higher than that observed over Rh/SrTiO3 (4 × 10−6 mol of H2 g catal. −1 min−1 (1.1 × 10−6 mol of H2 m catal. −2 min−1) compared to 0.7 × 10−6 mol of H2 g catal. −1 min−1 (5.5 × 10−8 mol of H2 m catal. −2 min−1), respectively, under UV excitation with a flux equivalent to that from the sun light (ca. 1 mW cm−2). Analyses of the XPS Rh3d and XPS Pt4f indicate that Rh is mainly present in its ionic form (Rh3+) while Pt is mainly present in its metallic form (Pt0). A fraction of the non-metallic state of Rh in the catalyst persisted even after argon ion sputtering. The tendency of Rh to be oxidized compared to Pt might be the reason behind the lower activity of the former compared to the later. On the contrary, a larger amount of methane are formed on the Rh containing catalyst compared to that observed on the Pt containing catalyst due to the capacity of Rh to break the carbon–carbon bond of the organic compound.

  14. Opinions on SKB's Safety Assessments SR 97 and SFL 3-5. A Review by SKI Consultants

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-12-01

    The Swedish Nuclear Fuel and Waste Management Co. (SKB) has presented their safety assessment 'Deep repository for spent nuclear fuel, SR 97 - Post-closure safety'. SKB's report is part of the documentation that has been required by the Government before the start of site investigations. The Swedish Nuclear Power Inspectorate (SKI) is reviewing SR 97 according to earlier Government decisions. In its review work SKI has asked several consultants, that recently have been performing research work for SKI, to give their opinions on SR 97. SKI and the Swedish Radiation Protection Institute (SSI) have used these reports from the consultants as one complementary basis for the formulation of the SKI/SSI review report. This is a compilation of the reports from the different consultants, and therefore the different contributions vary in length, style and language. Included are also two consultant reports, giving comments on SKB's preliminary safety assessment for SFL 3-5 (deep repository for long-lived low- and intermediate-level waste). The 17 contributions have all been separately indexed.

  15. High mobility conduction at (110) and (111) LaAlO3/SrTiO3 interfaces.

    Science.gov (United States)

    Herranz, G; Sánchez, F; Dix, N; Scigaj, M; Fontcuberta, J

    2012-01-01

    In recent years, striking discoveries have revealed that two-dimensional electron liquids (2DEL) confined at the interface between oxide band-insulators can be engineered to display a high mobility transport. The recognition that only few interfaces appear to suit hosting 2DEL is intriguing and challenges the understanding of these emerging properties not existing in bulk. Indeed, only the neutral TiO(2) surface of (001)SrTiO(3) has been shown to sustain 2DEL. We show that this restriction can be surpassed: (110) and (111) surfaces of SrTiO(3) interfaced with epitaxial LaAlO(3) layers, above a critical thickness, display 2DEL transport with mobilities similar to those of (001)SrTiO(3). Moreover we show that epitaxial interfaces are not a prerequisite: conducting (110) interfaces with amorphous LaAlO(3) and other oxides can also be prepared. These findings open a new perspective both for materials research and for elucidating the ultimate microscopic mechanism of carrier doping.

  16. Synthesis, structure, chemical doping and high pressure studies of the SrPt3 P with unique structure features

    Science.gov (United States)

    Jawdat, Benmaan; Lv, Bing; Zhu, Xiyu; Xue, Yuyi; Chu, Ching

    2013-03-01

    Superconductivity up to 8.4K was reported by Takayama et al.[3] in APt3P (A =Sr, Ca and La) in 2012 with structural information based only on X-ray powder refinement. The compounds are suggested to crystallize in an antiperovskite-based structure closely related to that of the heavy fermion superconductor CePt3Si but are nonpolar unlike CePt3Si. Both small single crystals and polycrystalline samples of SrPt3P, the compound with the highest Tc of this class of materials, are synthesized through solid state reactions. In this presentation, full and detailed structural information will be revealed based on X-ray single crystal analysis. Different chemical doping on different sites and high pressure studies have been carried out on the compound of SrPt3P. The results and its implication will be presented and discussed. Research at Houston is supported in part by US AFOSR, the State of Texas, T.L.L. Temple Foundation and John and Rebecca Moores Endowment.

  17. Luminescence investigations of rare earth doped lead-free borate glasses modified by MO (M = Ca, Sr, Ba)

    Energy Technology Data Exchange (ETDEWEB)

    Janek, Joanna, E-mail: janek.joanna@gmail.com; Sołtys, Marta; Żur, Lidia; Pietrasik, Ewa; Pisarska, Joanna; Pisarski, Wojciech A.

    2016-09-01

    Series of lead-free borate glasses with different oxide modifiers and lanthanide ions were prepared. The effect of oxide modifiers MO (M = Ca, Sr, Ba) on spectroscopic properties of trivalent Ln{sup 3+} (Ln = Eu, Er, Pr) were systematically investigated. Especially, the luminescence spectra of Ln{sup 3+}-doped lead-free borate glasses are presented and discussed in relation to the impact of selective components (CaO, SrO and BaO). Several spectroscopic parameters, such as the fluorescence intensity ratio R/O (Eu{sup 3+}) and measured luminescence lifetimes for the {sup 5}D{sub 0} (Eu{sup 3+}), {sup 4}I{sub 13/2} (Er{sup 3+}) and {sup 1}D{sub 2} (Pr{sup 3+}) excited states of lanthanide ions were analyzed in details. The research proved that spectroscopic properties of trivalent Ln{sup 3+} depend significantly on kind of presence oxide modifiers MO (M = Ca, Sr, Ba) in glass host matrices. - Highlights: • Luminescence of Ln{sup 3+}-doped borate glasses was presented and discussed. • Effect of glass modifiers on spectroscopic properties of rare earths was studied. • Measured luminescence lifetimes of Ln{sup 3+} (Ln = Eu, Er, Pr) were analyzed. • Luminescence intensity ratios R/O (Eu{sup 3+}) were determined.

  18. Subsolidus Phase Relations of the CoOx-CuO-SrO System  

    DEFF Research Database (Denmark)

    Grivel, Jean-Claude

    2017-01-01

    The subsolidus phase relations of the CoOx-CuO-SrO system were investigated in air. The samples were equilibrated at 900 °C. The pseudo-ternary section contains three stoichiometric binary oxide phases (Sr2CuO3, SrCuO2 and Sr14Cu24O41−δ) and a binary oxide solid solution: Sr6+xCo5O15+δ (0 ≤ x ≤ 0.......36). Two binary phases extend into the ternary system forming solid solutions, i.e., Sr14Cu24−xCoxO41−δ (0 ≤ x ≤ 5) and Sr6+xCo5−yCuyO15+δ (0 ≤ x ≤ 0.36, 0 ≤ y ≤ 1.0). The Sr6+xCo5O15+δ solid solution was found to undergo a phase separation into a mixture of Sr6Co5O15−δ and Sr14Co11O33 upon annealing...

  19. Encapsulation of Cs/Sr contaminated clinoptilolite in geopolymers produced from metakaolin

    Energy Technology Data Exchange (ETDEWEB)

    Kuenzel, C., E-mail: c.kuenzel08@imperial.ac.uk [Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW72AZ (United Kingdom); Centre for Advanced Structural Ceramics, Department of Materials, Imperial College London, South Kensington Campus, London SW72AZ (United Kingdom); Cisneros, J.F. [Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW72AZ (United Kingdom); Neville, T.P. [Centre for CO_2 Technology, Department of Chemical Engineering, University College London, Gower Street, London WC1E6JE (United Kingdom); Vandeperre, L.J. [Centre for Advanced Structural Ceramics, Department of Materials, Imperial College London, South Kensington Campus, London SW72AZ (United Kingdom); Simons, S.J.R.; Bensted, J. [Centre for CO_2 Technology, Department of Chemical Engineering, University College London, Gower Street, London WC1E6JE (United Kingdom); Cheeseman, C.R. [Department of Civil and Environmental Engineering, Imperial College London, South Kensington Campus, London SW72AZ (United Kingdom)

    2015-11-15

    The encapsulation of caesium (Cs) and strontium (Sr) contaminated clinoptilolite in Na and K based metakaolin geopolymers is reported. When Cs or Sr loaded clinoptilolite is mixed with a metakaolin geopolymer paste, the high pH of the activating solution and the high concentration of ions in solution cause ion exchange reactions and dissolution of clinoptilolite with release of Cs and Sr into the geopolymer matrix. The leaching of Cs and Sr from metakaolin-based geopolymer has therefore been investigated. It was found that Na-based geopolymers reduce leaching of Cs compared to K-based geopolymers and the results are in agreement with the hard and soft acids and bases (HSAB) theory. Cs ions are weak Lewis acids and aluminates are a weak Lewis base. During the formation of the geopolymer matrix Cs ions are preferentially bound to aluminate phases and replace Na in the geopolymer structure. Sr uptake by Na-geopolymers is limited to 0.4 mol Sr per mole of Al and any additional Sr is immobilised by the high pH which causes precipitation of Sr as low solubility hydroxide and carbonate phases. There was no evidence of any other phases being formed when Sr or Cs are added to metakaolin geopolymers. - Highlights: • Leaching. • Encapsulation of Cs and Sr. • Nuclear waste. • Clinoptilolite.

  20. SR Proteins Induce Alternative Exon Skipping through Their Activities on the Flanking Constitutive Exons▿

    Science.gov (United States)

    Han, Joonhee; Ding, Jian-Hua; Byeon, Cheol W.; Kim, Jee H.; Hertel, Klemens J.; Jeong, Sunjoo; Fu, Xiang-Dong

    2011-01-01

    SR proteins are well known to promote exon inclusion in regulated splicing through exonic splicing enhancers. SR proteins have also been reported to cause exon skipping, but little is known about the mechanism. We previously characterized SRSF1 (SF2/ASF)-dependent exon skipping of the CaMKIIδ gene during heart remodeling. By using mouse embryo fibroblasts derived from conditional SR protein knockout mice, we now show that SR protein-induced exon skipping depends on their prevalent actions on a flanking constitutive exon and requires collaboration of more than one SR protein. These findings, coupled with other established rules for SR proteins, provide a theoretical framework to understand the complex effect of SR protein-regulated splicing in mammalian cells. We further demonstrate that heart-specific CaMKIIδ splicing can be reconstituted in fibroblasts by downregulating SR proteins and upregulating a RBFOX protein and that SR protein overexpression impairs regulated CaMKIIδ splicing and neuronal differentiation in P19 cells, illustrating that SR protein-dependent exon skipping may constitute a key strategy for synergism with other splicing regulators in establishing tissue-specific alternative splicing critical for cell differentiation programs. PMID:21135118

  1. SR proteins induce alternative exon skipping through their activities on the flanking constitutive exons.

    Science.gov (United States)

    Han, Joonhee; Ding, Jian-Hua; Byeon, Cheol W; Kim, Jee H; Hertel, Klemens J; Jeong, Sunjoo; Fu, Xiang-Dong

    2011-02-01

    SR proteins are well known to promote exon inclusion in regulated splicing through exonic splicing enhancers. SR proteins have also been reported to cause exon skipping, but little is known about the mechanism. We previously characterized SRSF1 (SF2/ASF)-dependent exon skipping of the CaMKIIδ gene during heart remodeling. By using mouse embryo fibroblasts derived from conditional SR protein knockout mice, we now show that SR protein-induced exon skipping depends on their prevalent actions on a flanking constitutive exon and requires collaboration of more than one SR protein. These findings, coupled with other established rules for SR proteins, provide a theoretical framework to understand the complex effect of SR protein-regulated splicing in mammalian cells. We further demonstrate that heart-specific CaMKIIδ splicing can be reconstituted in fibroblasts by downregulating SR proteins and upregulating a RBFOX protein and that SR protein overexpression impairs regulated CaMKIIδ splicing and neuronal differentiation in P19 cells, illustrating that SR protein-dependent exon skipping may constitute a key strategy for synergism with other splicing regulators in establishing tissue-specific alternative splicing critical for cell differentiation programs.

  2. Transverse thermoelectric effect in La{sub 0.67}Sr{sub 0.33}MnO{sub 3}|SrRuO{sub 3} superlattices

    Energy Technology Data Exchange (ETDEWEB)

    Shiomi, Y. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Aoba-ku, Sendai 980-8577 (Japan); Handa, Y.; Kikkawa, T. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Saitoh, E. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Aoba-ku, Sendai 980-8577 (Japan); WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); CREST, Japan Science and Technology Agency, Tokyo 102-0076 (Japan); Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195 (Japan)

    2015-06-08

    Transverse thermoelectric effects in response to an out-of-plane heat current have been studied in an external magnetic field for ferromagnetic superlattices consisting of La{sub 0.67}Sr{sub 0.33}MnO{sub 3} and SrRuO{sub 3} layers. The superlattices were fabricated on SrTiO{sub 3} substrates by pulsed laser deposition. We found that the sign of the transverse thermoelectric voltage for the superlattices is opposite to that for La{sub 0.67}Sr{sub 0.33}MnO{sub 3} and SrRuO{sub 3} single layers at 200 K, implying an important role of spin Seebeck effects inside the superlattices. At 10 K, the magnetothermoelectric curves shift from the zero field due to an antiferromagnetic coupling between layers in the superlattices.

  3. Positron annihilation study of Sr Doping in La{sub 2-x}Sr{sub x}CuO{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Sterne, P.A. [Lawrence Livermore National Lab., CA (United States)]|[California Univ., Davis, CA (United States); Howell, R.H.; Fluss, M.J. [Lawrence Livermore National Lab., CA (United States); Kaiser, J.H. [Texas Univ., Arlington, TX (United States); Kitazawa, K. [Tokyo Univ. (Japan); Kojima, H. [Yamanashi Univ., Kofu (Japan)

    1993-04-22

    We present a combined experimental and threshold study of effects of Sr doping on electronic structure of La{sub 2-x}Sr{sub x}CuO{sub 4}. Electron-positron momentum distributions have been measured to high statistical precision (> 4 {times} 10{sup 8} counts) at room temperature for samples with Sr concentrations of x = 0.0, 0.1, 0.13 and 0.2. Analysis of all four spectra reveal strong features due to electron-positron wavefunction overlap, in quantitative agreement with theoretical calculations. The Sr doped samples show discontinuities consistent with presence of a Fermi surface. The form and position of these features are in general agreement with the predictions of band theory. Correspondence between theory and experiment, as well as some differences, are revealed by a detailed study of the changes in electron-position momentum density with increasing Sr doping.

  4. The Effect of Sr2+ on Luminescence of Ce3+-Doped (Ca,Sr)2Al2SiO7.

    Science.gov (United States)

    Lin, Litian; Shi, Rui; Zhou, Rongfu; Peng, Qi; Liu, Chunmeng; Tao, Ye; Huang, Yan; Dorenbos, Pieter; Liang, Hongbin

    2017-10-16

    A series of Ce3+-doped (Ca,Sr)2Al2SiO7 phosphors with different Ce3+ and Ca2+/Sr2+ concentrations were prepared by a high temperature solid-state reaction technique. To get insight into the structure-luminescence relationship, the impact of incorporation of Sr2+ on structure of (Ca,Sr)2Al2SiO7 was first investigated via Rietveld refinement of high quality X-ray diffraction (XRD) data, and then the VUV-UV excitation and UV-vis emission spectra of (Ca,Sr)2Al2SiO7:Ce3+ were collected at low temperature. The results reveal that the crystal structure evolution of (Ca,Sr)2Al2SiO7:Ce3+ has influences on band gaps and Ce3+ luminescence properties including 4f-5di (i = 1-5) transition energies, radiative lifetime, emission intensity, quantum efficiency, and thermal stability. Moreover, the influence of Sr2+ content on the energy of Eu3+-O2- charge-transfer states (CTS) in (Ca,Sr)2Al2SiO7:Eu3+ was studied in order to construct vacuum referred binding energy (VRBE) schemes with the aim to further understand the luminescence properties of (Ca,Sr)2Al2SiO7:Ce3+. Finally, X-ray excited luminescence (XEL) spectra were measured to evaluate the possibility of (Ca,Sr)2Al2SiO7:Ce3+ as a scintillation material.

  5. WE-D-BRE-01: A Sr-90 Irradiation Device for the Study of Cutaneous Radiation Injury

    Energy Technology Data Exchange (ETDEWEB)

    Dorand, JE; Bourland, JD [Department of Radiation Oncology and Department of Physics, Wake Forest University, Winston-Salem, NC (United States); Burnett, LR [KeraNetics, LLC, Winston-Salem, NC (United States); Tytell, M [Department of Neurobiology and Anatomy, Wake Forest School of Medicine, Winston-Salem, NC (United States)

    2014-06-15

    Purpose: To determine dosimetric character for a custom-built Sr-90 beta irradiator designed for the study of Cutaneous Radiation Injury (CRI) in a porcine animal model. In the event of a radiological accident or terrorist event, Sr-90, a fission by-product, will likely be produced. CRI is a main concern due to the low energy and superficial penetration in tissue of beta particles from Sr-90. Seven 100 mCi plaque Sr-90 radiation sources within a custom-built irradiation device create a 40 mm diameter region of radiation-induced skin injury as part of a larger project to study the efficacy of a topical keratin-based product in CRI healing. Methods: A custom-built mobile irradiation device was designed and implemented for in vivo irradiations. Gafchromic™ EBT3 radiochromic film and a PTW Markus chamber type 23343 were utilized for dosimetric characterization of the beta fluence at the surface produced by this device. Films were used to assess 2-dimensional dose distribution and percent depth dose characteristics of the radiation field. Ion chamber measurements provided dose rate data within the field. Results: The radiation field produced by the irradiation device is homogeneous with high uniformity (∼5%) and symmetry (∼3%) with a steep dose fall-off with depth from the surface. Dose rates were determined to be 3.8 Gy/min and 3.3 Gy/min for film and ion chamber measurements, respectively. A dose rate of 3.4 Gy/min was used to calculate irradiation times for in vivo irradiations. Conclusion: The custom-built irradiation device enables the use of seven Sr-90 beta sources in an array to deliver a 40 mm diameter area of homogeneous skin dose with a dose rate that is useful for research purposes and clinically relevant for the induction of CRI. Doses of 36 and 42 Gy successfully produce Grade III CRI and are used in the study of the efficacy of KeraStat™. This project has been funded in whole or in part with Federal funds from the Biomedical Advanced Research and

  6. Concentrations and ratios of Sr, Ba and Ca along an estuarine river to the Gulf of Mexico - implication for sea level rise effects on trace metal distribution

    Science.gov (United States)

    He, S.; Xu, Y. J.

    2015-11-01

    Strontium and barium to calcium ratios are often used as proxies for tracking animal movement across salinity gradients. As sea level rise continues, many estuarine rivers in the world face saltwater intrusion, which may cause changes in mobility and distribution of these metals upstream. Despite intensive research on metal adsorption and desorption in marine systems, knowledge of the spatiotemporal distribution of these elements along estuarine rivers is still limited. In this study, we conducted an intensive monitoring of Sr and Ba dynamics along an 88 km long estuary, the Calcasieu River in South Louisiana, USA, which has been strongly affected by saltwater intrusion. Over the period from May 2013 to August 2015, we collected monthly water samples and performed in-situ water quality measurements at six sites from the upstream to the river mouth, with a salinity range from 0.02 to 29.50 ppt. Water samples were analyzed for Sr, Ba, and Ca concentrations. In-situ measurements were made on salinity, pH, water temperature, dissolved oxygen concentration, and specific conductance. We found that the Sr and Ca concentrations and the Sr / Ca ratio all increased significantly with increasing salinity. The average Sr concentration at the site closest to the Gulf of Mexico (site 6) was 46.21 μmol L-1, which was about 130 times higher than that of the site furthest upstream (site 1, 0.35 μmol L-1). The average Ca concentration at site 6 was 8.19 mmol L-1, which was about 60 times higher than that of site 1 (0.13 mmol L-1). The average Sr / Ca ratio at site 6 (8.41 mmol mol-1) was about 3 times the average Sr / Ca ratio at site 1 (2.89 mmol mol-1). However, the spatial variation in Ba concentration was marginal, varying from 0.36 μmol L-1 at site 6 to 0.47 at site 5. The average Ba / Ca ratio at site 1 (4.82 mmol mol-1) was about 54 times the average Ba / Ca ratio at site 6 (0.09 mmol mol-1), showing a clear negative relation between the Ba / Ca ratio and increasing

  7. Crystalline phases and electronic structures in superconducting Bi{endash}Sr{endash}Ca{endash}Cu oxides

    Energy Technology Data Exchange (ETDEWEB)

    Giardina, M.D.; Feduzi, R.; Inzaghi, D.; Manara, A. [Institute for Advanced Materials, C.E.C. Joint Research Centre, Ispra Establishment, 21020 Ispra (Vatican City State, Holy See) (Italy); Giori, C. [Istituto di Scienze Fisiche, Universita di Parma, 43100 Parma (Italy); Sora, I.N. [Dipartimento di Chimica e Fisica per i Materiali, Universita di Brescia, 25100 Brescia (Italy); Dallacasa, V. [Istituto Policattedra, Universita di Verona, 37100 Verona (Italy)

    1997-08-01

    Two classes of samples, designated A and B, of layered Bi{endash}Sr{endash}Ca{endash}Cu oxides having the same nominal composition 4:3:3:4, but different thermal histories, were investigated by using field modulated microwave absorption (ESR), powder x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and x-ray absorption near the edge structure (XANES). Previous electrical resistivity measurements showed that the B samples only presented two superconducting phases with midpoints of the transition temperatures at {approximately}80K and {approximately}105K. The microwave absorption technique indicated instead the presence of islands which became superconducting at the above-mentioned temperatures also in the A samples. The crystalline and electronic structures of the two types of samples are illustrated and discussed. A plausible theoretical interpretation of the experimental results, based on a quantum percolation model with Coulomb interaction, is also given. {copyright} {ital 1997 Materials Research Society.}

  8. Knockdown expression and hepatic deficiency reveal anatheroprotective role for SR-BI in liver and peripheral tissues

    Energy Technology Data Exchange (ETDEWEB)

    Huby, Thierry; Doucet, Chantal; Dachet, Christiane; Ouzilleau,Betty; Ueda, Yukihiko; Afzal, Veena; Rubin, Edward; Chapman, M. John; Lesnik, Philippe

    2006-07-18

    Scavenger receptor SR-BI has been implicated inHDL-dependent atheroprotective mechanisms. We report the generation of anSR-BI conditional knockout mouse model in which SR-BI gene targeting byloxP site insertion produced a hypomorphic allele (hypomSR-BI).Attenuated SR-BI expression in hypomSR-BI mice resulted in 2-foldelevation in plasma total cholesterol (TC) levels. Cre-mediated SR-BIgene inactivation of the hypomorphic SR-BI allele in hepatocytes(hypomSR-BI-KOliver) was associated with high plasma TC concentrations,increased plasma free cholesterol/TC (FC/TC) ratio, and alipoprotein-cholesterol profile typical of SR-BI-/- mice. Plasma TClevels were increased 2-fold in hypomSR-BI and control mice fed anatherogenic diet, whereas hypomSR-BI-KOliver and SR-BI-/- mice developedsevere hypercholesterolemia due to accumulation of FC-rich, VLDL-sizedparticles. Atherosclerosis in hypomSR-BI mice was enhanced (2.5-fold)compared with that in controls, but to a much lower degree than inhypomSR-BI-KOliver (32-fold) and SR-BI-/- (48-fold) mice. The lattermodels did not differ in either plasma lipid levels or in the capacity ofVLDL-sized lipoproteins to induce macrophage cholesterol loading.However, reduced atherosclerosis in hypomSR-BI-KOliver mice wasassociated with decreased lesional macrophage content as compared withthat in SR-BI-/- mice. These data imply that, in addition to its majoratheroprotective role in liver, SR-BI may exert an antiatherogenic rolein extrahepatic tissues.

  9. Half metallicity in Sr{sub 2}CrOsO{sub 6} via Na doping

    Energy Technology Data Exchange (ETDEWEB)

    Zu, Ningning [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Wang, Jing [Key Laboratory of Applied Chemistry, Yanshan University, Qinhuangdao 066004 (China); Wang, Ying, E-mail: ywang_2012@ciac.ac.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Wu, Zhijian, E-mail: zjwu@ciac.ac.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

    2015-07-05

    Highlights: • Na-doped Sr{sub 2}CrOsO{sub 6} is investigated by using the density functional theory. • Both NaSr{sub 5}Cr{sub 3}Os{sub 3}O{sub 18} and NaSrCrOsO{sub 6} are half metals. • The Curie temperature of NaSr{sub 5}Cr{sub 3}Os{sub 3}O{sub 18} and NaSrCrOsO{sub 6} is higher than room temperature. - Abstract: The insulating Sr{sub 2}CrOsO{sub 6} has the highest Curie temperature of 725 K among the double perovskites so far. In this study, by doping with Na, NaSr{sub 5}Cr{sub 3}Os{sub 3}O{sub 18} and NaSrCrOsO{sub 6} are investigated by using the density functional theory. The calculated results indicated that the hole generated by Na goes to Os 5d t{sub 2g} orbitals. This makes one of the insulating spin channels in Sr{sub 2}CrOsO{sub 6} to be metallic in the Na-doped compounds. Thus, they become half metals. The estimated magnetic ordering temperature is 579 K for NaSr{sub 5}Cr{sub 3}Os{sub 3}O{sub 18} and 615 K for NaSrCrOsO{sub 6}, which are higher than the room temperature. Therefore, we expect that the Na-doped Sr{sub 2}CrOsO{sub 6} would be promising candidates as spintronic material.

  10. Strong kinetic effects on Sr/Ca ratios in the calcitic bivalve

    OpenAIRE

    Lorrain, Anne; Gillikin, David Paul; Paulet, Yves-Marie; Chauvaud, L.; Le Mercier, Alain; Navez, Jacques; André, Luc

    2005-01-01

    International audience; Although Sr/Ca ratios in abiogenic calcite are strongly controlled by precipitation rates, such a kinetic effect has never been demonstrated in calcitic bivalve shells. Therefore, we report Sr/Ca ratios together with daily growth rates in the calcitic shells of 4 individuals of the bivalve Pecten maximus (age class I). Ratios of Sr/Ca were found to be variable among individuals that grew at the same location, illustrating that vital effects dominate over environmental ...

  11. Superconductivity dependent on the amount of Bi and Sr in the Bi{sub 2}Sr{sub 2}CuO{sub 6} compounds

    Energy Technology Data Exchange (ETDEWEB)

    Wu, C.H. [Department of Chemistry, Tamkang University, Tamsui 251, Taiwan (China); Chu, Y.C.; Ling, D.C.; Liu, S.H.; Pong, W.F. [Department of Physics, Tamkang University, Tamsui 251, Taiwan (China); Hseu, H.S.; Chen, J.M.; Lee, J.F. [National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan (China); Kao, H.-C.I. [Department of Chemistry, Tamkang University, Tamsui 251, Taiwan (China)], E-mail: kaohci@mail.tku.edu.tw

    2007-09-01

    Two series of samples with nominal compositions of Bi{sub 2+x}Sr{sub 2}CuO{sub y} and Bi{sub 2}Sr{sub 2-x}CuO{sub y} (0 {<=} x {<=} 0.10) were prepared by a conventional solid-state reaction method. Laminar morphology is observed for all the samples under SEM. EDS analysis shows that Bi is slightly volatile, the depletion amount is about 3% in the Bi rich samples, but only about 1% loses in the Sr deficient samples. Hole concentration of the Bi{sub 2}Sr{sub 2-x}CuO{sub y} series increases with increasing x, showing a hole doping effect caused by the depletion of the Sr ions. In contrary, Bi{sub 2+x}Sr{sub 2}CuO{sub y} series has a hole filling effect by introducing the extra Bi ions. These samples show metallic conducting behavior in the normal state and superconducting property at lower temperature. T{sub c} decreases with increasing x on both series. Bi{sub 2}Sr{sub 2}CuO{sub y} has the highest T{sub c} at 7.9 K with an optimal hole concentration of 0.237. Hole concentrations obtained from the O-K edge XANES spectra and the iodometric titration agree well in these samples.

  12. Hybrid HF-DFT comparative study of SrZrO3 and SrTiO3(001) surface properties

    Science.gov (United States)

    Evarestov, R. A.; Bandura, A. V.; Alexandrov, V. E.

    2006-10-01

    Hybrid HF-DFT LCAO simulations of SrZrO3 and SrTiO3(001) surface properties are performed in a single-slab model framework. The SrZrO3(001) surface was studied by an ab initio method for the first time. Three slab models with different surface terminations including up to 8 atomic planes were used for calculation of the various surface characteristics (surface energies, atomic charges, density of electronic states). The dependence of the results on the chosen model and on the kind of d -element is analyzed. The dissimilarity in the surface oxygen atom contributions to the total density of states of two crystals is attributed to the more ionic nature of Zr-O bonds compared to Ti-O bonds. It is found that in the case of SrZrO3 the electronic density is biased towards the SrO-terminated surface and this surface should be more basic in nature than the SrO surface of SrTiO3 crystal.

  13. Hybrid HF-DFT comparative study of SrZrO{sub 3} and SrTiO{sub 3}(001) surface properties

    Energy Technology Data Exchange (ETDEWEB)

    Evarestov, R.A.; Bandura, A.V.; Alexandrov, V.E. [Department of Quantum Chemistry, St. Petersburg State University, 26 Universitetskii Prospekt, Stary Petergof, 198504 St. Petersburg (Russian Federation)

    2006-10-15

    Hybrid HF-DFT LCAO simulations of SrZrO{sub 3} and SrTiO{sub 3}(001) surface properties are performed in a single-slab model framework. The SrZrO{sub 3}(001) surface was studied by an ab initio method for the first time. Three slab models with different surface terminations including up to 8 atomic planes were used for calculation of the various surface characteristics (surface energies, atomic charges, density of electronic states). The dependence of the results on the chosen model and on the kind of d-element is analyzed. The dissimilarity in the surface oxygen atom contributions to the total density of states of two crystals is attributed to the more ionic nature of Zr-O bonds compared to Ti-O bonds. It is found that in the case of SrZrO{sub 3} the electronic density is biased towards the SrO-terminated surface and this surface should be more basic in nature than the SrO surface of SrTiO{sub 3} crystal. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  14. Data report for the safety assessment SR-Site

    Energy Technology Data Exchange (ETDEWEB)

    2010-12-15

    This report compiles, documents, and qualifies input data identified as essential for the long-term safety assessment of a KBS-3 repository, and forms an important part of the reporting of the safety assessment project SR-Site. The input data concern the repository system, broadly defined as the deposited spent nuclear fuel, the engineered barriers surrounding it, the host rock, and the biosphere in the proximity of the repository. The input data also concern external influences acting on the system, in terms of climate related data. Data are provided for a selection of relevant conditions and are qualified through traceable standardised procedures

  15. Hydrogen Mobility in Disordered Metals Studied by $\\mu$SR

    CERN Multimedia

    2002-01-01

    A few studies of the behaviour of positive muons in metal hydrides have been made during the last three years under the code SC76, although this code is intended primarily for ``diffusion and trapping of positive muons`` in pure or very weakly doped metals. It has been shown in these studies that $\\mu$SR can provide important information even in concentrated hydrides like $ NbH _{,} _{0},7 - _{0} _{,} _{9} $ and $ Zr V _{2} H _{2} _{m}inus _{3} $ especially concerning mutual $\\mu

  16. Multi-spectrozonal detectors for temporal-resolved SR experiments

    CERN Document Server

    Fedotov, M G

    2001-01-01

    This paper considers the structure of the special integrating-mode X-ray detectors allowing the division of the range of their working energies into a few relatively independent sub-ranges. The recording of signals for all sub-ranges is carried out simultaneously (during one bunch passing in the SR source) and from the same area of the detector. It is expected that the application of such detectors for the studies of short-time processes will permit estimation of the variation of the spectrum of the recorded radiation, which violently simplifies the interpretation of the results.

  17. Geosphere process report for the safety assessment SR-Can

    Energy Technology Data Exchange (ETDEWEB)

    Skagius, Kristina [Kemakta Konsult AB, Stockholm (SE)] (ed.)

    2006-09-15

    This report documents geosphere processes identified as relevant to the long-term safety of a KBS- repository, and forms an important part of the reporting of the safety assessment SR-Can. The detailed assessment methodology, including the role of the process report in the assessment, is described in the SR-Can Main report. The following excerpts describe the methodology, and clarify the role of this process report in the assessment. The repository system, broadly defined as the deposited spent nuclear fuel, the engineered barriers surrounding it, the host rock and the biosphere in the proximity of the repository, will evolve over time. Future states of the system will depend on the initial state of the system, a number of radiation related, thermal, hydraulic, mechanical, chemical and biological processes acting within the repository system over time, and external influences acting on the system. A methodology in ten steps has been developed for SR-Can described below. Identification of factors to consider (FEP processing): This step consists of identifying all the factors that need to be included in the analysis. Experience from earlier safety assessments and KBS-specific and international databases of relevant features, events and processes influencing long-term safety are utilised. Based on the results of the FEP processing, an SR-Can FEP catalogue, containing FEPs to be handled in SR-Can, has been established. The initial state of the system is described based on the design specifications of the KBS repository, a descriptive model of the repository site and a site-specific layout of the repository. The initial state of the fuel and the engineered components is that immediately after deposition, as described in the SR-Can Initial state report. The initial state of the geosphere and the biosphere is that of the natural system prior to excavation, as described in the site descriptive models. The repository layouts adapted to the sites are provided in underground

  18. Characterisation of a Sr-90 based electron monochromator

    CERN Document Server

    Arfaoui, S; CERN; Casella, C; ETH Zurich

    2015-01-01

    This note describes the characterisation of an energy filtered Sr-90 source to be used in laboratory studies that require Minimum Ionising Particles (MIP) with a kinetic energy of up to approx. 2 MeV. The energy calibration was performed with a LYSO scintillation crystal read out by a digital Silicon Photomultiplier (dSiPM). The LYSO/dSiPM set-up was pre-calibrated using a Na-22 source. After introducing the motivation behind the usage of such a device, this note presents the principle and design of the electron monochromator as well as its energy and momentum characterisation.

  19. Evidence for sudden of rotational structure in heavy Sr nuclides

    CERN Document Server

    Azuma, R E; Carraz, L C; Hansen, P G; Jonson, B; Mattsson, S; Nielsen, O B; Nyman, G H; Ravn, H L

    1980-01-01

    The authors give evidence for rotational 2/sup +/ and 4/sup +/ levels in /sup 100/Sr. The nuclide /sub 37//sup 100/Rb with half-life of 55 ms was produced by mass separation at the ISOLDE Facility by bombarding a uranium carbide target with 600 MeV protons. The gamma- ray spectrum shows peaks that the authors interpret from systematics as the 4/sup +/ to 2/sup +/ and 2/sup +/ to 0/sup +/ gamma-ray transitions in strontium. Similar measurements on /sup 98/Rb confirm earlier findings by Wollnick et al. (1977). The level diagrams clearly show an abrupt onset of deformation at N=60. (4 refs).

  20. Spin Measurements of n +87Sr for Level Density Studies

    Science.gov (United States)

    Gunsing, F.; Fraval, K.; Mathelie, M.; Valenta, S.; Bečvář, F.; Rusev, G.; Tonchev, A. P.; Mitchell, G.; Baramsai, B.; Altstadt, S.; Andrzejewski, J.; Audouin, L.; Barbagallo, M.; Bécares, V.; Belloni, F.; Berthoumieux, E.; Billowes, J.; Boccone, V.; Bosnar, D.; Brugger, M.; Calviani, M.; Calviño, F.; Cano-Ott, D.; Carrapiço, C.; Cerutti, F.; Chiaveri, E.; Chin, M.; Colonna, N.; Cortés, G.; Cortés-Giraldo, M. A.; Diakaki, M.; Domingo-Pardo, C.; Duran, I.; Dressler, R.; Eleftheriadis, C.; Ferrari, A.; Ganesan, S.; García, A. R.; Giubrone, G.; Gonçalves, I. F.; González-Romero, E.; Griesmayer, E.; Guerrero, C.; Hernández-Prieto, A.; Jenkins, D. G.; Jericha, E.; Kadi, Y.; Käppeler, F.; Karadimos, D.; Koehler, P.; Kokkoris, M.; Krtička, M.; Kroll, J.; Lampoudis, C.; Langer, C.; Leal-Cidoncha, E.; Lederer, C.; Leeb, H.; Leong, L. S.; Losito, R.; Manousos, A.; Marganiec, J.; Martínez, T.; Massimi, C.; Mastinu, P. F.; Mastromarco, M.; Mendoza, E.; Mengoni, A.; Milazzo, P. M.; Mingrone, F.; Mirea, M.; Mondalaers, W.; Paradela, C.; Pavlik, A.; Perkowski, J.; Plompen, A.; Praena, J.; Quesada, J. M.; Rauscher, T.; Reifarth, R.; Riego, A.; Robles, M. S.; Rubbia, C.; Sabaté-Gilarte, M.; Sarmento, R.; Saxena, A.; Schillebeeckx, P.; Schmidt, S.; Schumann, D.; Tagliente, G.; Tain, J. L.; Tarrío, D.; Tassan-Got, L.; Tsinganis, A.; Vannini, G.; Variale, V.; Vaz, P.; Ventura, A.; Vermeulen, M. J.; Vlachoudis, V.; Vlastou, R.; Wallner, A.; Ware, T.; Weigand, M.; Weiß, C.; Wright, T.; Žugec, P.

    2014-05-01

    We have used the 4π BaF2 gamma-ray detector array at the n_TOF neutron time-of-flight facility at CERN for an experiment in order to determine the spins of resonances of n +87Sr by measuring the gamma-ray spectra and multiplicity distributions. The first results are presented here. We have assigned the orbital momentum ℓ to all evaluated resonances on the basis of their neutron widths. Further we have assigned the spin J to 16 s-wave resonances on based the population of low-lying levels.

  1. Electrical resistance of SrFeO2 at ultra high pressure

    Science.gov (United States)

    Kikuchi, Masayoshi; Kagayama, Tomoko; Shimizu, Katsuya; Kageyama, Hiroshi

    2015-03-01

    SrFeO2 shows antiferromagnetic and insulating order at ambient pressure. The crystal structure of SrFeO2 has 2-dementional FeO2 plate and is interested in because this is common structure of high temperature superconductor. SrFeO2 has M-I, magnetic and spin transition with applying pressure. If magnetism disappears and metallization occurs with applying pressure, SrFeO2 may show superconductivity because of the crystal structure, so we measured electrical resistance at high pressure up to 150 GPa and low temperature down to 100 mK.

  2. Multiferroic properties of Sr-doped BiFeO3 nanoparticles

    Science.gov (United States)

    Dhir, Gitanjali; Uniyal, Poonam; Verma, N. K.

    2018-02-01

    The effects of 'Sr-doping' and 'particle size' on multiferroic properties of BiFeO3 nanoparticles were studied. Structural analysis revealed no influence on the rhombohedral structure of BiFeO3 with Sr-doping in the synthesized nanoparticles. The particle size of Sr-doped BiFeO3 nanoparticles was tailored by varying calcination temperature. The crystallite size got reduced with Sr-doping and also on decreasing the calcination temperature. Lattice strain was observed to enhance with reducing particle size of Sr-doped BiFeO3 nanoparticles. Magnetic measurements confirmed enhancement in magnetization via suppression of spin cycloidal structure with Sr-doping owing to creation of oxygen vacancies, enhanced lattice strain and reduction in particle size. Dielectric analysis revealed deterioration of dielectric constant of BiFeO3 with Sr-doping due to the formation of oxygen vacancies. Further, on reducing particle size of Sr-doped BiFeO3 nanoparticles, both saturation magnetization and dielectric constant values registered increase. Lowering of the magnetic phase transition temperature with particle size of Sr-doped BiFeO3 nanoparticles indicated weakening of magnetic exchange interactions.

  3. Gold-tin ordering in SrAu{sub 2}Sn{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Schwickert, Christian; Gerke, Birgit; Poettgen, Rainer [Univ. Muenster (Germany). Inst. fuer Anorganische und Analytische Chemie

    2014-07-15

    Samples of the solid solutions SrAu{sub x}Sn{sub 4-x} (1.7 ≤ x ≤ 2.2) were obtained by high-frequency melting of the elements in sealed niobium ampoules. Powder and single-crystal X-ray data confirmed the CaBe{sub 2}Ge{sub 2}-type structure, space group P4/nmm. The structures of SrAu{sub 1.76}Sn{sub 2.24}, SrAu{sub 2}Sn{sub 2}, SrAu{sub 2.16}Sn{sub 1.84} (crystal A), SrAu{sub 2.16}Sn{sub 1.84} (crystal B), and SrAu{sub 2.22}Sn{sub 1.78} were refined from single-crystal diffractometer data. Only the SrAu{sub 2}Sn{sub 2} crystal shows complete Au-Sn ordering while all other crystals show substantial mixed occupancies on the four crystallographically independent sites of the polyanionic networks in which the strontium atoms fill cages of coordination number 16. Temperature-dependent susceptibility measurements have revealed diamagnetism for SrAu{sub 2}Sn{sub 2}. {sup 119}Sn Moessbauer spectroscopic data of a bulk SrAu{sub 2}Sn{sub 2} sample have resolved the tetrahedral and square-pyramidal tin sites but point to substantial Au-Sn disorder.

  4. Conductivity of SrTiO3 based oxides in the reducing atmosphere at high temperature

    DEFF Research Database (Denmark)

    Hashimoto, Shin-Ichi; Poulsen, Finn Willy; Mogensen, Mogens Bjerg

    2007-01-01

    The conductivities of several donor-doped SrTiO3 based oxides, which were prepared in air, were studied in a reducing atmosphere at high temperature. The conductivities of all specimens increased slowly with time at 1000 degrees C in 9% H-2/N-2, even after 100 h. Nb-doped SrTiO3 showed relatively...... at 500-800 degrees C, while that of La-doped SrTiO3 dropped immediately on exposure to air. The conduction behavior of Nb-doped SrTiO3 was explained by reduction of Ti4+ and/or Nb5+ and the relatively slow oxygen diffusibility. (c) 2006 Elsevier B.V. All rights reserved.......The conductivities of several donor-doped SrTiO3 based oxides, which were prepared in air, were studied in a reducing atmosphere at high temperature. The conductivities of all specimens increased slowly with time at 1000 degrees C in 9% H-2/N-2, even after 100 h. Nb-doped SrTiO3 showed relatively...... fast reduction and high conductivity compared with the other SrTiO3 based oxides. The conductivity of Nb-doped SrTiO3 was ca. 50 S cm(-1) at 500 degrees C after reduction at 1200 degrees C. After strong reduction, the conductivity of Nb-doped SrTiO3 was almost independent of the oxygen partial pressure...

  5. Evidence of existence of metastable SrFe{sub 12}O{sub 19} nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Garcia, R., E-mail: rmartinez@fi.uba.ar [Laboratorio de Solidos Amorfos, INTECIN, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, C1063ACV, Buenos Aires (Argentina); Bilovol, V.; Socolovsky, L.M. [Laboratorio de Solidos Amorfos, INTECIN, Facultad de Ingenieria, Universidad de Buenos Aires, Paseo Colon 850, C1063ACV, Buenos Aires (Argentina); Pirota, K. [Laboratorio de Materiais e Baixas Temperaturas, Instituto de Fisica ' Gleb Wataghin' , UNICAMP, 13083-970 Campinas, SP (Brazil)

    2011-12-15

    The existence of metastable hexaferrite is reported. Synthesis of strontium hexaferrite, SrFe{sub 12}O{sub 19}, at 400 deg. C was realized under controlled oxygen atmosphere. Such technique allows obtaining of SrFe{sub 12}O{sub 19} at lower temperatures than those by traditional methods (above 800 deg. C). Phase transformation occurred during a measurement of magnetization vs. temperature (heating up to 625 deg. C). The heat treatment induces a change from SrFe{sub 12}O{sub 19} to {gamma}-Fe{sub 2}O{sub 3} (as the main phase), and SrFeO{sub 2.74} to Sr{sub 2}Fe{sub 2}O{sub 5}. Together with these phase transformations, an increment in the amount of SrCO{sub 3} is detected. Magnetic study of the samples, before and after the heating, supports the structural analysis conclusions. - Highlights: > SrFe{sub 12}O{sub 19}, as the majority phase, is obtained by heat treatment at 400 deg. C under oxygen flux. > Hexaferrite nanoparticles have crystalline imperfections that make it an unstable phase. > Together with these phase transformations, an increment in the amount of SrCO{sub 3} is detected. > To our knowledge, this is the first report of the existence of metastable SrFe{sub 12}O{sub 19}.

  6. Encapsulation of Cs/Sr contaminated clinoptilolite in geopolymers produced from metakaolin

    Science.gov (United States)

    Kuenzel, C.; Cisneros, J. F.; Neville, T. P.; Vandeperre, L. J.; Simons, S. J. R.; Bensted, J.; Cheeseman, C. R.

    2015-11-01

    The encapsulation of caesium (Cs) and strontium (Sr) contaminated clinoptilolite in Na and K based metakaolin geopolymers is reported. When Cs or Sr loaded clinoptilolite is mixed with a metakaolin geopolymer paste, the high pH of the activating solution and the high concentration of ions in solution cause ion exchange reactions and dissolution of clinoptilolite with release of Cs and Sr into the geopolymer matrix. The leaching of Cs and Sr from metakaolin-based geopolymer has therefore been investigated. It was found that Na-based geopolymers reduce leaching of Cs compared to K-based geopolymers and the results are in agreement with the hard and soft acids and bases (HSAB) theory. Cs ions are weak Lewis acids and aluminates are a weak Lewis base. During the formation of the geopolymer matrix Cs ions are preferentially bound to aluminate phases and replace Na in the geopolymer structure. Sr uptake by Na-geopolymers is limited to 0.4 mol Sr per mole of Al and any additional Sr is immobilised by the high pH which causes precipitation of Sr as low solubility hydroxide and carbonate phases. There was no evidence of any other phases being formed when Sr or Cs are added to metakaolin geopolymers.

  7. Metal-Mott insulator transition of SrMnO3 by fluorine doping

    Science.gov (United States)

    Ramwala, Mohini; Singh, Deobrat; Gupta, Sanjeev K.; Sonvane, Yogesh

    2017-05-01

    We have studied the electronic band structure based metallic properties of a pure cubic SrMnO3 and fluorine doped cubic SrMnO3 peroskite crystal structure which has mott-insulating properties. We also found the stable cubic structure using Generalised Gradient Approximation (GGA) in Perder-Burke-Ernzerhof (PBE) through First-principles calculation. The bond structure of pure SrMnO3 signifies its metallic behavior and that of fluorine doped SrMnO3 show mottness. These materials are of great importance in microelectronics and telecommunication.

  8. Subsolidus phase relations of the SrO–SbOx–CuO system at 1140K in air

    DEFF Research Database (Denmark)

    Grivel, J.-C.; Norby, Poul; Andersen, Niels Hessel

    2014-01-01

    The subsolidus phase relations of the SrO–SbOx–CuO system were investigated in air. The samples were equilibrated at 1140K. Under these conditions, 7 binary oxide phases are stable: Sr2CuO3, SrCuO2, Sr14Cu24O41−δ, CuSb2O6, SrSb2O6, Sr2Sb2O7 and Sr7Sb2O12. The ternary section contains 10 three......-phase regions. A new ternary oxide phase with an approximate Sr3Sb2CuO9 composition of was identified. It structure is related to that of Sr8W3CuO18. This phase is not superconducting above 2K. Instead, the magnetic susceptibility indicates onset of weak ferro- or ferrimagnetism at T≈30K....

  9. Physiological studies in heterozygous calcium sensing receptor (CaSR gene-ablated mice confirm that the CaSR regulates calcitonin release in vivo

    Directory of Open Access Journals (Sweden)

    Kovacs Christopher S

    2004-04-01

    Full Text Available Abstract Background The calcium sensing receptor (CaSR regulates serum calcium by suppressing secretion of parathyroid hormone; it also regulates renal tubular calcium excretion. Inactivating mutations of CaSR raise serum calcium and reduce urine calcium excretion. Thyroid C-cells (which make calcitonin express CaSR and may, therefore, be regulated by it. Since calcium stimulates release of calcitonin, the higher blood calcium caused by inactivation of CaSR should increase serum calcitonin, unless CaSR mutations alter the responsiveness of calcitonin to calcium. To demonstrate regulatory effects of CaSR on calcitonin release, we studied calcitonin responsiveness to calcium in normal and CaSR heterozygous-ablated (Casr+/- mice. Casr+/- mice have hypercalcemia and hypocalciuria, and live normal life spans. Each mouse received either 500 μl of normal saline or one of two doses of elemental calcium (500 μmol/kg or 5 mmol/kg by intraperitoneal injection. Ionized calcium was measured at baseline and 10 minutes, and serum calcitonin was measured on the 10 minute sample. Results At baseline, Casr+/- mice had a higher blood calcium, and in response to the two doses of elemental calcium, had greater increments and peak levels of ionized calcium than their wild type littermates. Despite significantly higher ionized calcium levels, the calcitonin levels of Casr+/- mice were consistently lower than wild type at any ionized calcium level, indicating that the dose-response curve of calcitonin to increases in ionized calcium had been significantly blunted or shifted to the right in Casr+/- mice. Conclusions These results confirm that the CaSR is a physiological regulator of calcitonin; therefore, in response to increases in ionized calcium, the CaSR inhibits parathyroid hormone secretion and stimulates calcitonin secretion.

  10. Provenance of loess in the central Great Plains, U.S.A. based on Nd-Sr isotopic composition, and paleoenvironmental implications

    Science.gov (United States)

    Yang, Yang; Mason, Joseph A.; Zhang, Hanzhi; Lu, Huayu; Ji, Junfeng; Chen, Jun; Liu, Lianwen

    2017-10-01

    Loess of the central Great Plains, U.S.A., records intervals of Quaternary aeolian dust accumulation at rates among the highest known worldwide. This study used Nd-Sr isotopic analysis to investigate the provenance of Middle Pleistocene to Holocene loess in western and central Nebraska, U.S.A., essential information for understanding the paleoenvironmental conditions that allowed such rapid accumulation to occur at some times and not others. Nd-Sr isotopic data suggest that dust from unglaciated Great Plains landscapes has been the primary component of loess accumulated at both very high and low rates since the Middle Pleistocene. However, loess isotopic compositions all require an additional minor source with higher 87Sr/86Sr and lower εNd, most likely debris from Precambrian rocks in the Rocky Mountains, carried to the Great Plains by the Platte River system. The contribution from this secondary source-probably including glacially eroded sediment-was greater in Marine Isotope Stage (MIS) 3 and early MIS 2, but decreased somewhat just after the last glacial maximum (LGM) at the Bignell Hill section. Earlier research showed that the highest accumulation rates in that section also occurred after the LGM; thus our results likely indicate increased dust emission from unglaciated landscapes at that time. Greater plant moisture stress in a warming climate with still-low CO2 could have played a role in that increased dust production, along with lagged vegetation response; however, a strengthened westerly component of surface winds is the most straightforward explanation.

  11. Multi-species coral Sr/Ca based sea-surface temperature reconstruction data using Orbicella faveolata and Siderastrea siderea from Dry Tortugas National Park, Florida

    Science.gov (United States)

    Flannery, Jennifer A.; Richey, Julie N.; Thirumalai, Kaustubh; Poore, Richard Z.; Delong, Kristine

    2016-01-01

    New sub annual and mean annual Sr/Ca records from two species of massive coral, Orbicella faveolata (coral B3) and Siderastrea siderea (coral CG2), from the Dry Tortugas National Park, FL (DRTO). Both corals have well-constrained chronologies, with coral B3 ranging from 1893-2008 and coral CG2 ranging from 1837-2012. We combine these new records with published Sr/Ca data from three additional S. siderea coral colonies (DeLong et al., 2014) to generate a 278-year-long multi-species composite Sr/Ca-SST record from DRTO. This new record from a region sensitive to the Atlantic Multidecadal Oscillation (AMO) and Atlantic Meridional Overturning Circulation (AMOC) variations provides insight into the link between the two systems. Also included are new annual linear extension rates for each species. The coral samples and derived data were collected under the National Park Service Scientific Research and Collecting permits DRTO-2008-SCI-0015 and DRT0-2012-SCI-0001; accession numbers DRTO-241 and DRTO-353. For further information regarding data collection and/or processing methods refer to Flannery, J. A., J. N. Richey, K. Thirumalai, R. Z. Poore, and K. L. DeLong, 2016, Multi-species coral Sr/Ca based sea-surface temperature reconstruction using Orbicella faveolata and Siderastrea siderea from the Florida Straits, Palaeogeography, Palaeoclimatology, Palaeoecology, ISSN 0031-0182, http://dx.doi.org/10.1016/j.palaeo.2016.10.022.

  12. Levels in {}3880Sr, {}3983Y and {}4083Zr and the New Region of Strong Deformation around N=Z≈38

    Science.gov (United States)

    Ramayya, A. V.; Herath-Banda, M. A.; Barclay, M.; Hamilton, J. H.; Ma, W. C.; Soundranayagam, R.; Pancholi, S. C.; Yamada, H.; Cleemann, L.; Schmal, N.; Eberth, J.; Heck, T.; Roth, J.; Koenig, W.; Martin, B.

    The energy levels in {}3983Y and {}4083Zr were identified and investigated along with 80Sr via in-beam γ-ray spectroscopy to explore the new region of strong deformation centered around N=Z=38. The reaction 51V(32S, p2n)80Sr was studied at the Holifield Heavy Ion Research Facility and reactions 54Fe(32S, α2p)80Sr 54Fe(32S, 3p)83Y and 54Fe(32S, 2pn)83Zr at the Max Planck Tandem. The deformation in the ground state band in 80Sr observed to 12+ shows a significant increase as N decreases toward 38. A 9/2+ ground state band in {}3983Y observed to (29/2+) exhibits larger deformation than an excited (9/2+) band in {}4083Zr as expected as Z moves away from 38. These nuclei support the proposal that the large deformation observed in this region arises from the reinforcing of the proton and neutron shape driving force as both N and Z approach shell gaps at large deformation for N and Z of 38.

  13. The Determination of 11B/10B and 87Sr/86Sr Isotope Ratios by ...

    African Journals Online (AJOL)

    NICO

    'boron memory effect', interference of the large 12C at mass 11, and matrix interferences peculiar to wine and digested wine. RESEARCH ARTICLE. C. Vorster, L. Greeff and P.P. Coetzee,. 207. S. Afr. J. Chem., 2010, 63, 207–214,. . *To whom all correspondence should be addressed.

  14. Anti-angiogenic effects of the thienopyridine SR 25989 in vitro and in vivo in a murine pulmonary metastasis model

    Science.gov (United States)

    Mah-Becherel, M C M; Céraline, J; Deplanque, G; Chenard, M-P; Bergerat, J-P; Cazenave, J-P; Klein-Soyer, C

    2002-01-01

    Neovascularisation is a key step in tumour growth and establishment of distant metastases. We have recently demonstrated that the thienopyridine SR 25989 an enantiomer of the anti-aggregant clopidogrel (Plavix®) lacking anti-aggregant activity, inhibits endothelial cell proliferation in vitro by increasing the expression of endogenous thrombospondin-1, a natural potent inhibitor of angiogenesis. The anti-angiogenic effect of SR 25989 was further assessed in vitro in a quantitative assay of angiogenesis comprising a fragment of rat aorta embedded in a fibrin gel and in vivo in a pulmonary metastatic model using C57BL/6 mice inoculated in the foot pad with the highly metastatic melanoma cell line B16 F10. SR 25989 induced a dose dependent inhibition of spontaneous microvessel development in vitro reaching half maximal inhibition at around less than 50 μM and caused platelet derived growth factor induced angiogenesis to regress as a function of thienopyridine concentration. In vivo, SR 25989 did not alter significantly the growth rate of the primary tumour in the foot pad and did not inhibit development of inguinal nodes which appeared after amputation. However, the number and size of lung metastases were reduced in treated animals when examined at the time of sacrifice. In addition, the few metastases over 1 mm3 did not show any neovascularisation, as confirmed by negative von Willebrand immunostaining and in contrast to intense vascularisation seen in metastases developed by control mice. These results confirm that SR 25989 possesses potent anti-angiogenic properties and is able to inhibit metastatic dissemination and growth. The lack of effect on the primary tumour and inguinal nodes illustrates the complexity of the mechanisms involved in tumoural neo-angiogenesis and points out the possibility for distinct processes leading to neovascularisation in primary tumour as opposed to metastases. British Journal of Cancer (2002) 86, 803–810. DOI: 10.1038/sj

  15. Superconductivity in the Bi-Sr-Ca-Cu oxide compositional diagram. [BiSrCaCuO

    Energy Technology Data Exchange (ETDEWEB)

    Vaile, R.A.; Bosi, S.; Puzzer, T.; Bailey, A.; Cochrane, J.; Mondinos, N.; Sealey, K.; Russell, G.J.; Matthews, D.N.; Aristides, M.

    1988-08-01

    Careful study of the distribution of room temperature resistance in the quaternary compositional diagram of the Bi-Sr-Ca-Cu oxides has demonstrated a wide range of materials which exhibit superconducting transitions in the temperature range 60-110 K. Energy dispersive analysis has shown that these are multiphase materials with a number of common phases which appear to be responsible for the observed superconductivity. Among these is the 2212 composition which has been reported previously and two new phases with stoichiometries 2213 and 2215.

  16. 90Sr and 137Cs in Arctic echinoderms.

    Science.gov (United States)

    Saniewski, Michał; Borszcz, Tomasz

    2017-11-15

    Radionuclides in the Arctic echinoderms have seldom been studied despite their considerable environmental importance. This manuscript covers the results of 90Sr and 137Cs measurements in common echinoderm taxa collected from the Svalbard Bank in the Barents Sea and from two High-Arctic fjords (Isfjorden and Magdalenefjorden). We focused on the echinoid, Strongylocentrotus droebachiensis, the asteroid, Henricia sanguinolenta, and the ophiuroid, Ophiopolis aculeata. For all echinoderms, the analysis revealed a negative correlation between 90Sr activity and the mass. Thus, we concluded that metals are accumulated faster at a young age when the growth is most rapid. The highest average activities of 137Cs followed the order O. aculeata>H. sanguinolenta>S. droebachiensis. This suggests that bioaccumulation was highly taxon-dependent and could reflect differences in the isotope exposures associated with the diet of echinoderms. The study provides a baseline for understanding radionuclide processes in the High-Arctic benthic echinoderm communities. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. First Combined SCT/TRT Cosmics Seen in SR1

    CERN Multimedia

    M. Jose Costa; H. Pernegger

    A major milestone for the Inner Detector project has been accomplished in early May as cosmic rays going through both the barrel Semiconductor Tracker (SCT) and Transition Radiation Tracker (TRT) have been successfully recorded in the SR1 building on the ATLAS experimental site at CERN. A cosmic-ray track in the combined SCT-TRT barrel As reported also in this issue of the eNews, in February of this year the SCT barrel was inserted into the TRT in the SR1 building. One eighth of the TRT barrel and a quarter of the SCT barrel were then cabled to power supplies and to the data acquisition system in order to verify the good operation of the detector before installation in the ATLAS cavern. After first checks of noise levels in the final detectors, a critical goal was to study its response to cosmic rays using a set of scintillators to give the external trigger, thus undertaking the enormous challenge of integrating the full chain of the detectors, the DAQ, and the reconstruction and monitoring software. A ...

  18. Development of Creep Resistant Mg-Al-Sr Alloys

    Science.gov (United States)

    Pekguleryuz, Mihriban O.; Baril, Eric

    There have been attempts since in the 70's to develop creep resistant magnesium diecasting alloys for automotive applications such as automatic-transmission case and engine components. The earliest die casting alloys developed as a result of these activities were the Mg-Al- RE and Mg-Al-Si systems (AE and AS alloys). The shortcomings of these two alloy systems related to high cost or borderline properties have led to renewed activity in the 90's in the development of magnesium alloys with improved elevaied-temperature properties. This paper presents the development of a new family of creep-resistant Mg alloys based on the Mg-Al-Sr system. Creep resistance, the tensile yield strength and the bolt-load-retention of these alloys at 150°C and 175°C show improvement over Mg-Al-RE and Mg-Al-Si system. The microstructure of the alloys is characterized by Al-Sr-(Mg) containing intermetallic second phases. The absence of the Mg17Al12 phase in the microstructure, either creep-induced or as-cast, is one of the factors that contribute to improved creep-resistance of these alloys over the Mg-Al based diecasting alloys. Furthermore, the alloys exhibit better salt-spray corrosion resistance (0.09-0.15mg/cm2/day) than other commercial magnesium diecasting alloys such as AM60B, AS41, AE42 and the aluminum diecasting alloy A380.

  19. Pixel Detector Trial Assembly Test in the SR1 building

    CERN Multimedia

    D. Giugni

    2004-01-01

    During the last two months the Pixel group [LBL, Milan and Wuppertal] made a successful integration test on the mechanics of the barrel. The scope of the test was to qualify the integration procedures and the various assembling tools. The test took place in the clean room of the SR1 building at CERN, where the detector has been assembled around a dummy beam pipe made of Stainless Steel. The process is rather complex: the shells come in two parts and they have to be clamped together to get the full shell. This operation is carried out by a dedicated tool which is shown to the right in the picture below. The layer 1 shell is clamped around a "service" pipe that will be used for moving the full layer to the integration tool [ITT] which is visible on the left. View of the tools devoted to the Pixel barrel integration in the SR1 building Also visible in the picture is the global frame that is actually held by the tool. It will engage the layers sliding onto the rails. The first two layers are sequentially...

  20. SrMnII2MnIII(PO43

    Directory of Open Access Journals (Sweden)

    Ghaleb Alhakmi

    2013-09-01

    Full Text Available The title compound, strontium trimanganese tris(orthophosphate, was synthesized under hydrothermal conditions. Its structure is isotypic to that of the lead analogue PbMnII2MnIII(PO43. Two O atoms are in general positions, whereas all others atoms are in special positions. The Sr and one P atom exhibit mm2 symmetry, the MnII atom 2/m symmetry, the MnIII atom and the other P atom .2. symmetry and two O atoms are located on mirror planes. The three-dimensional network of the crystal structure is made up of two types of chains running parallel to [010]. One chain is linear and is composed of alternating MnIIIO6 octahedra and PO4 tetrahedra sharing vertices; the other chain has a zigzag arrangement and is built up from two edge-sharing MnIIO6 octahedra connected to PO4 tetrahedra by edges and vertices. The two types of chains are linked through PO4 tetrahedra, leading to the formation of channels parallel to [100] and [010] in which the SrII ions are located. They are surrounded by eight O atoms in the form of a slightly distorted bicapped trigonal prism.

  1. Strontium-90 ({sup 90}Sr) determination using liquid scintillation counting

    Energy Technology Data Exchange (ETDEWEB)

    Cheberle, L.T.V.; Rosa, M.M.L.; Ferreira, M.T.; Taddei, M.H.T. [Comissao Nacional de Energia Nuclear (LAPOC/CNEN-MG), Pocos de Caldas, MG (Brazil). Laboratorio de Pocos de Caldas

    2015-07-01

    This procedure describes a method for separation and measurement of strontium {sup 90}Sr in water, soils, and biological samples. Water samples may be concentrated using evaporation or calcium phosphate coprecipitation. Soils and biological materials must be dissolved using wet digestion. Tracers and carriers must be added before the attack. Radioactive strontium is separated employing a specific resin before determination by liquid scintillation counting using the double energetic window method. The resin is used to concentrate strontium from samples. Stable strontium is used to monitor method yields and correct results to improve precision and accuracy. The presence of elemental strontium in the sample may bias the gravimetric yield determination. If it is suspected that natural strontium is present in the sample, its concentration should be determined by a suitable means (ICP), and the yield calculation properly modified. Sr-Spec resin with an 8M HNO{sub 3} load solution is used to effectively remove {sup 140}Ba and {sup 40}K isotopes, as well as other interferences from the matrix. Tetravalent plutonium, neptunium, cerium and ruthenium, however, are not removed using nitric acid. The radiochemical procedure was tested using PROCORAD intercomparison exercises and PNI samples. (author)

  2. Anisotropic Magnetoresistance in Antiferromagnetic Sr_{2}IrO_{4}

    Directory of Open Access Journals (Sweden)

    C. Wang

    2014-11-01

    Full Text Available We report point-contact measurements of anisotropic magnetoresistance (AMR in a single crystal of antiferromagnetic Mott insulator Sr_{2}IrO_{4}. The point-contact technique is used here as a local probe of magnetotransport properties on the nanoscale. The measurements at liquid nitrogen temperature reveal negative magnetoresistances (up to 28% for modest magnetic fields (250 mT applied within the IrO_{2} a-b plane and electric currents flowing perpendicular to the plane. The angular dependence of magnetoresistance shows a crossover from fourfold to twofold symmetry in response to an increasing magnetic field with angular variations in resistance from 1% to 14%. We tentatively attribute the fourfold symmetry to the crystalline component of AMR and the field-induced transition to the effects of applied field on the canting of antiferromagnetic-coupled moments in Sr_{2}IrO_{4}. The observed AMR is very large compared to the crystalline AMRs in 3d transition metal alloys or oxides (0.1%–0.5% and can be associated with the large spin-orbit interactions in this 5d oxide while the transition provides evidence of correlations between electronic transport, magnetic order, and orbital states. The finding of this work opens an entirely new avenue to not only gain a new insight into physics associated with spin-orbit coupling but also to better harness the power of spintronics in a more technically favorable fashion.

  3. Model summary report for the safety assessment SR-Can

    Energy Technology Data Exchange (ETDEWEB)

    Vahlund, Fredrik

    2006-10-15

    This document is the model summary report for the safety assessment SR-Can. In the report, the quality assurance measures conducted for the assessment codes are presented together with the chosen methodology. In the safety assessment SR-Can, a number of different computer codes are used. In order to better understand how these codes are related Assessment Model Flowcharts, AMFs, have been produced within the project. From these, it is possible to identify the different modelling tasks and consequently also the different computer codes used. A large number of different computer codes are used in the assessment of which some are commercial while others are developed especially for the current assessment project. QA requirements must on the one hand take this diversity into account and on the other hand be well defined. In the methodology section of the report the following requirements are defined: It must be demonstrated that the code is suitable for its purpose; It must be demonstrated that the code has been properly used; and, It must be demonstrated that the code development process has followed appropriate procedures and that the code produces accurate results. Although the requirements are identical for all codes, the measures used to show that the requirements are fulfilled will be different for different codes (for instance due to the fact that for some software the source-code is not available for review). Subsequent to the methodology section, each assessment code is presented and it is shown how the requirements are met.

  4. Rb-Sr dating of sphalerites from Mississippi Valley-type (MVT) ore deposits

    Science.gov (United States)

    Nakai, Shun'ichi; Halliday, Alex N.; Kesler, Stephen E.; Jones, Henry D.; Kyle, J. Richard; Lane, Thomas E.

    1993-01-01

    Mississippi Valley-type (MVT) ore deposits are epigenetic carbonate-hosted Pb-Zn deposits that contain galena, sphalerite, fluorite, barite, dolomite, calcite, and quartz. Although they are thought to form from basinal brines, their exact origins are still unclear, partly because of the scarcity of reliable geochronological data. Rb-Sr dating of sphalerites has recently been shown to be a promising technique for the direct dating of ore minerals in MVT deposits. This paper reports the results of a reconnaissance study of sphalerites, their fluid inclusions, and associated minerals from MVT deposits of North America. Sphalerites from Immel mine, Mascot-Jefferson City district, east Tennessee, define a Rb-Sr age of 347 ± 20 Ma consistent with a Rb-Sr age of 377 ± 29 Ma for sphalerites from Coy mine in the same district, but inconsistent with models that ascribe their genesis to the effects of the late Paleozoic Alleghenian orogeny. Rb-Sr isotopic analyses of K-feldspar from Immel mine preclude the possibility that the Rb-Sr data reflect feldspar inclusions. Sphalerites from the main ore zone of Daniel's Harbour mine, New foundland, do not form a linear isochron and open behavior of the Rb-Sr system is suspected. Sphalerites from the Pine Point district, Northwest Territories, Canada, define a Rb-Sr age of 361 ± 13 Ma, indicating that the mineralization took place shortly after the deposition of the middle Devonian host carbonate rocks. These results are not compatible with mineralization models based on regional fluid migration related to early Tertiary Cordilleran deformation. Sphalerites from northern Arkansas have very low Rb and Sr concentrations (less than 0.1 ppm). The Rb-Sr data do not form isochrons and the sphalerites have higher 87Sr /86Sr ratios than expected, given their Rb/Sr ratios and reasonable constraints on their ages. The sphalerites are suspected to contain clay inclusions; and it is likely that the Sr isotopic compositions of these sphalerites

  5. Strontium isotope fractionation during strontianite (SrCO3) dissolution, precipitation and at equilibrium

    Science.gov (United States)

    Mavromatis, Vasileios; Harrison, Anna L.; Eisenhauer, Anton; Dietzel, Martin

    2017-12-01

    In this study we examine the behavior of stable Sr isotopes between strontianite [SrCO3] and reactive fluid during mineral dissolution, precipitation, and at chemical equilibrium. Experiments were performed in batch reactors at 25 °C in 0.01 M NaCl solutions wherein the pH was adjusted by bubbling of a water saturated gas phase of pure CO2 or atmospheric air. The equilibrium Sr isotope fractionation between strontianite and fluid after dissolution of the solid under 1 atm CO2 atmosphere was estimated as Δ88/86SrSrCO3-fluid = δ88/86Sr SrCO3 - δ88/86Srfluid = -0.05 ± 0.01‰. On the other hand, during strontianite precipitation, an enrichment of the fluid phase in 88Sr, the heavy isotopomer, was observed. The evolution of the δ88/86Srfluid during strontianite precipitation can be modeled using a Rayleigh distillation approach and the estimated, kinetically driven, fractionation factor αSrCO3-fluid between solid and fluid is calculated to be 0.99985 ± 0.00003 corresponding to Δ88/86SrSrCO3-fluid = -0.15‰. The obtained results further support that under chemical equilibrium conditions between solid and fluid a continuous exchange of isotopes occurs until the system approaches isotopic equilibrium. This isotopic exchange is not limited to the outer surface layer of the strontianite crystal, but extends to ∼7-8 unit cells below the crystal surface. The behavior of Sr isotopes in this study is in excellent agreement with the concept of dynamic equilibrium and it suggests that the time needed for achievement of chemical equilibrium is generally shorter compared to that for isotopic equilibrium. Thus it is suggested that in natural Sr-bearing carbonates an isotopic change may still occur close to thermodynamic equilibrium, despite no observable change in aqueous elemental concentrations. As such, a secondary and ongoing change of Sr isotope signals in carbonate minerals caused by isotopic re-equilibration with fluids has to be considered in order to use Sr

  6. Application of LA-MC-ICP-MS for analysis of Sr isotope ratios in speleothems

    Science.gov (United States)

    Weber, Michael; Scholz, Denis; Wassenburg, Jasper A.; Jochum, Klaus Peter; Breitenbach, Sebastian

    2017-04-01

    Speleothems are well established climate archives. In order to reconstruct past climate variability, several geochemical proxies, such as δ13C and δ18O as well as trace elements are available. Since several factors influence each individual proxy, robust interpretation is often hampered. This calls for multi-proxy approaches involving additional isotope systems that can help to delineate the role of different sources of water within the epikarst and changes in soil composition. Sr isotope ratios (87Sr/86Sr) have been shown to provide useful information about water residence time and water mixing in the host rock. Furthermore, Sr isotopes are not fractionated during calcite precipitation, implying that the 87Sr/86Sr ratio of the speleothem provides a direct record of the drip water. While most speleothem studies applying Sr isotopes used the TIMS methodology, LA-MC-ICP-MS has been utilized for several other archives, such as otoliths and teeth. This method provides the advantage of faster data acquisition, higher spatial resolution, larger sample throughput and the absence of chemical treatment prior to analysis. Here we present the first LA-MC-ICP-MS Sr isotope data for speleothems. The analytical uncertainty of our LA-MC-ICP-MS Sr data is in a similar range as for other carbonate materials. The results of different ablation techniques (i.e. line scan and spots) are reproducible within error, implying that the application of this technique on speleothems is possible. In addition, several comparative measurements of different carbonate reference materials (i.e. MACS-3, JCt-1, JCp-1), such as tests with standard bracketing and comparison of the 87Sr/86Sr ratios with nanosecond laser ablation system and a state-of-the-art femtosecond laser ablation system, show the robustness of the method. We applied the method to samples from Morocco (Grotte de Piste) and India (Mawmluh Cave). Our results show only very small changes in the 87Sr/86Sr ratios of both speleothems

  7. Computational fluid dynamic (CFD) analysis on ALUDRA SR-10 UAV with parachute recovery system

    Science.gov (United States)

    Saim, R.; Mohd, S.; Shamsudin, S. S.; Zulkifli, M. F.; Omar, Z.; Subari@Rahmat, Z.; Masrom, M. F. Mohd; Zaki, Y.

    2017-09-01

    In an operation, belly landing is mostly applied as recovery method especially on research Unmanned Aerial Vehicle (UAV) such as Aludra SR-10. This type of landing method may encounter tough landing on hard soil and gravel which create high impact load on the aircraft. The impact may cause structural or system damage which costly to be repaired. Nowadays, Parachute Recovery System (PRS) recently used in numerous different tasks such as landing purpose to replace belly landing technique. Parachute use in this system to slow down flying or falling UAV to a safe landing by opening the canopy to increase aerodynamic drag. This paper was described the Computational Fluid Dynamic (CFD) analysis on ALUDRA SR-10 model with two different conditions i.e. the UAV equipped with and without parachute in order to identify the changes of aerodynamic characteristics. This simulation studies using solid models of aircraft and hemisphere parachute and was carried out by using ANSYS 16.0 Fluent under steady and turbulent flow and was modelled using the k-epsilon (k-ε) turbulence model. This simulation was limited to determine the drag force and drag coefficient. The obtained result showed that implementation of parachute increase 0.25 drag coefficient of the aircraft that is from 0.93 to 1.18. Subsequent to the reduction of descent rate caused by the parachute, the drag force of the aircraft increase by 0.76N. These increasing of drag force of the aircraft will produce lower terminal velocity which is expected to reduce the impact force on the aircraft during landing.

  8. Estudio dieléctrico de cerámicas de textura y microestructura controladas con composiciones (SrBi2Nb2O91-x(Bi3TiNbO9x

    Directory of Open Access Journals (Sweden)

    Pardo, L.

    2002-02-01

    Full Text Available Ceramics of composition (SrBi2Nb2O91-x(Bi3TiNbO9x with x = 0.35, 0.65 and 1.00 and Aurivillius type structure have been prepared by natural sintering and hot pressing. Amorphous precursors were obtained by mechanochemical activation of stoichiometric mixtures of oxides and carbonates, which allows using moderate processing temperatures. These materials are interesting for their use as high temperature piezoelectrics. Dielectric characterisation allows to know the temperature at what takes place the ferro-paraelectric transition, which limits the working temperature of the material. It also gives information on how the electric properties, especially the d. c. conductivity, affect the polarizability of the ceramics. The properties relation with the microstructure and the texture is studied. In this work, dielectric studies of these materials have been made, in the frequency interval from 100 Hz to 5 MHz and in the temperature range from 200 ºC up to the ferroparaelectric transition temperatures (>900 ºC for Bi3TiNbO9.Se han preparado cerámicas de la solución sólida (SrBi2Nb2O91-x(Bi3TiNbO9x con x = 0.35, 0.65 y 1.00 y estructura tipo Aurivillius obtenidas por sinterización natural y por prensado en caliente. Se parte de precursores amorfos obtenidos por activación mecanoquímica de una mezcla estequiométrica de óxidos y carbonatos, lo que permite utilizar temperaturas moderadas de procesado. Estos materiales son interesantes por su posible uso como piezoeléctricos de alta temperatura. La caracterización dieléctrica permite establecer a qué temperatura se encuentra la transición ferro-paraeléctrica que limita la temperatura de uso del material y como afectan las propiedades eléctricas, especialmente la conductividad d. c., a la polarizabilidad de las cerámicas, así como su relación con su microestructura y textura. En este trabajo se ha realizado el estudio dieléctrico de estos materiales en el intervalo de frecuencias de 100

  9. Effect of a CGO buffer layer on the performance of (La0.6Sr0.40.995Co0.2Fe0.8O3-δ cathode in YSZ-Based SOFC

    Directory of Open Access Journals (Sweden)

    Ruiz-Morales, J. C.

    2010-02-01

    Full Text Available The electrochemical properties of (La0.6Sr0.40.995Co0.2Fe0.8O3-s (LSCF and LSCF-gadolinium-doped ceria (CGO composite electrodes towards oxygen reduction were studied by impedance spectroscopy in a symmetric cell configuration using yttriastabilised zirconia (YSZ as electrolyte and a CGO buffer layer between the electrode and the electrolyte materials. The best polarisation resistance values were obtained for a LSCF-CGO (60/40, wt.% composite with values ranging between 0.07 and 0.4 Ωcm2 in the temperature range of 650-775ºC. The effect of the CGO buffer on the polarisation resistance of the LSCF electrode and the series resistance of the symmetrical LSCF/YSZ cell was also investigated. In addition, X-ray diffraction analysis was carried out to study the chemical compatibility between LSCF, YSZ and CGO materials.Las propiedades electroquímicas de los electrodos (La0.6Sr0.40.995Co0.2Fe0.8O3-δ (LSCF y composites de LSCF con ceria dopada con gadolinio (CGO, respecto la reacción de reducción del oxígeno, fueron estudiadas mediante espectroscopía de impedancia usando una configuración de celda simétrica, con circonia estabilizada con itria (YSZ como electrolito y CGO como capa de protección entre el material de electrodo y electrolito. Los mejores valores de resistencia de polarización fueron obtenidos para el composite LSCF-CGO (60/40, % en peso con valores comprendidos entre 0,07 y 0,4 Ωcm2 para el rango de temperaturas de 650-775ºC. El efecto de la capa intermedia de CGO sobre la resistencia de polarización del electrodo LSCF y la resistencia en serie de la celda simétrica LSCF/YSZ fue también investigado. La compatibilidad química de LSCF, YSZ y CGO se ha estudiado mediante difracción de rayos X.

  10. Ab initio calculations and analysis of chemical bonding in SrTiO3 and SrZrO3 cubic crystals

    Science.gov (United States)

    Evarestov, R. A.; Tupitsyn, I. I.; Bandura, A. V.; Alexandrov, V. E.

    The possibility of the different first-principles methods to describe the chemical bonding in SrTiO3 and SrZrO3 cubic crystals is investigated. The local properties of the electronic structure (atomic charges, bond orders, atomic delocalization indexes, and polarization fractions) were calculated with different methods: traditional Mulliken population analysis in LCAO calculations, two projection techniques in plane-wave (PW) calculations, population analysis based on Wannier-type atomic orbitals, and chemical bonding analysis based on the localized Wannier functions for occupied (valence band) LCAO states. All the techniques considered except the traditional Mulliken analysis demonstrate that the ionicity of chemical bonding in SrZrO3 is larger than in SrTiO3, in agreement with the Zr and Ti electronegativities relation and the relative bandgaps observed.

  11. Determining the origin of contemporary thermal springs by analyzing the isotopic couples (/sup 7/Li//sup 6/Li, /sup 87/Sr//sup 86/Sr)

    Energy Technology Data Exchange (ETDEWEB)

    Plyusnin, G.S.; Lomonosov, I.S.; Posokhov, V.F.

    1978-11-11

    A study was made of the isotopic composition of lithium for contemporary thermal springs of variable chemical composition. Data are presented on the isotopic ratios of /sup 7/Li//sup 6/Li and /sup 87/Sr//sup 86/Sr in contemporary thermal springs in the Baikal reef zone and in Kamchatka, and a diagram is presented illustrating the interconnection between the isotopic compositions of lithium and strontium in the thermal springs of the Baikal reef zone. An analysis of the data indicates that the dilution by cold meteogenic waters plays a significant role in the formation of thermal springs of the Baikal reef zone, since that dilution is inversely proportionate to the /sup 7/Li//sup 6/Li ratio and directly proportionate to the /sup 87/Sr//sup 86/Sr ratio. 12 references, 1 figure, 1 table.

  12. Two-dimensional electron gas in a modulation-doped SrTiO{sub 3}/Sr(Ti, Zr)O{sub 3} heterostructure

    Energy Technology Data Exchange (ETDEWEB)

    Kajdos, Adam P.; Cain, Tyler A.; Stemmer, Susanne [Materials Department, University of California, Santa Barbara, California 93106-5050 (United States); Ouellette, Daniel G. [Department of Physics, University of California, Santa Barbara, California 93106-9530 (United States)

    2013-08-19

    A two-dimensional electron gas (2DEG) in SrTiO{sub 3} is created via modulation doping by interfacing undoped SrTiO{sub 3} with a wider-band-gap material, SrTi{sub 1−x}Zr{sub x}O{sub 3}, which is doped n-type with La. All layers are grown using hybrid molecular beam epitaxy. Using magnetoresistance measurements, we show that electrons are transferred into the SrTiO{sub 3}, and a 2DEG is formed. In particular, Shubnikov-de Haas oscillations are shown to depend only on the perpendicular magnetic field. Experimental Shubnikov-de Haas oscillations are compared with calculations that assume multiple occupied subbands.

  13. 90Sr liquid scintillation urine analysis utilizing different approaches for tracer recovery.

    Energy Technology Data Exchange (ETDEWEB)

    Piraner, Olga; Preston, Rose T.; Shanks, Sonoya Toyoko; Jones, Robert

    2010-08-01

    90Sr is one of the isotopes most commonly produced by nuclear fission. This medium lived isotope presents serious challenges to radiation workers, the environment, and following a nuclear event, the general public. Methods of identifying this nuclide have been in existence for a number of years (e.g. Horwitz, E.P. [1], Maxwell, S.L.[2], EPA 905.0 [3]) which are time consuming, requiring a month or more for full analysis. This time frame is unacceptable in the present security environment. It is therefore important to have a dependable and rapid method for the determination of Sr. The purposes of this study are to reduce analysis time to less than half a day by utilizing a single method of radiation measurement while continuing to yield precise results. This paper presents findings on three methods that can meet this criteria; (1) stable Sr carrier, (2) 85Sr by gamma spectroscopy, and (3) 85Sr by LSC. Two methods of analyzing and calculating the 85Sr tracer recovery were investigated (gamma spectroscopy and a low energy window-Sr85LEBAB by LSC) as well as the use of two different types of Sr tracer (85Sr and stable Sr carrier). Three separate stock blank urine samples were spiked with various activity levels of 239Pu, 137Cs, 90Sr /90Y to determine the effectiveness of the Eichrome Sr-spec resin 2mL extractive columns. The objective was to compare the recoveries of 85Sr versus a stable strontium carrier, attempt to compare the rate at which samples can be processed by evaluating evaporation, neutralization, and removing the use of another instrument (gamma spectrometer) by using the LSC spectrometer to obtain 85Sr recovery. It was found that when using a calibration curve comprised of a different cocktail and a non-optimum discriminator setting reasonable results (bias of « 25%) were achieved. The results from spiked samples containing 85Sr demonstrated that a higher recovery is obtained when using gamma spectroscopy (89-95%) than when using the LEB window

  14. Biological response of Sr-containing coating with various surface treatments on titanium substrate for medical applications

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Shih-Ping [Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan (China); Lee, Tzer-Min, E-mail: tmlee@mail.ncku.edu.tw [Institute of Oral Medicine, National Cheng Kung University, Tainan, Taiwan (China); School of Dentistry, Kaohsiung Medical University, Kaohsiung, Taiwan (China); Lui, Truan-Sheng [Department of Materials Science and Engineering, National Cheng Kung University, Tainan, Taiwan (China)

    2015-08-15

    Graphical abstract: - Highlights: • Sr-containing coating prepared by plasma spraying and micro-arc oxidation process, respectively. • MAO coating stimulated high ECM-like structures of cells on early stage. • Sr-containing specimens had high cell responses on late stage. • Sr-MAO coating is a desirable implant surface treatment for clinical applications. - Abstract: An implant requires a suitable surface to trigger osteointegration. The surface characteristics and chemical composition are important factors in this process. Plasma spraying and micro-arc oxidation can be used to fabricate rough and porous structures for medical applications. Strontium (Sr) has been shown to prevent osteoporosis in vitro and in vivo. However, few scientists have evaluated the biological response of Sr-containing coatings on different surface treatments. In this study, a sand-blasted (SB) surface (as the control), plasma-sprayed hydroxyapatite (HA) and Sr-substituted HA coatings (HAPS and SrHAPS, respectively), calcium phosphate and Sr-containing calcium phosphate micro-arc oxidation surface (CPM and SrCPM, respectively) were analyzed in terms of human osteoblastic cell (MG63) response. Sr was confirmed to be incorporated into the surface. SrHAPS and SrCPM specimens had higher cell responses than those of the HAPS and CPM groups, respectively. The cells cultured on SrCPM and SrHAPS specimens exhibited high proliferation and differentiation. However, CPM and SrCPM specimens stimulated more ECM-like structures than other specimens. The results show that Sr-containing coatings have good characteristics that enhance cell response. The SrCPM coating is a suitable implant surface treatment for clinical applications.

  15. Transformation of Structure, Electrical Conductivity, and Magnetism in AA'Fe2O6-δ, A = Sr, Ca and A' = Sr.

    Science.gov (United States)

    Hona, Ram Krishna; Huq, Ashfia; Mulmi, Suresh; Ramezanipour, Farshid

    2017-08-21

    The ability to control electrical properties and magnetism by varying the crystal structure using the effect of the A-site cation in oxygen-deficient perovskites has been studied in AA'Fe 2 O 6-δ , where A = Sr, Ca and A' = Sr. The structure of Sr 2 Fe 2 O 6-δ , synthesized at 1250 °C in air, contains dimeric units of FeO 5 square pyramids separated by FeO 6 octahedra. Here we show that this ordering scheme can be transformed by changing the A-site cations from Sr to Ca. This leads to a structure where layers of corner-sharing FeO 6 octahedra are separated by chains of FeO 4 tetrahedra. Through systematic variation of the A-site cations, we have determined the average ionic radius required for this conversion to be ∼1.41 Å. We have demonstrated that the magnetic structure is also transformed. The Sr 2 compound has an incommensurate magnetic structure, where magnetic moments are in spin-density wave state, aligning perpendicular to the body diagonal of the unit cell. With the aid of neutron diffraction experiments at 10 and 300 K, we have shown that the magnetic structure is converted into a long-range G-type antiferromagnetic system when one Sr is replaced by Ca. In this G-type ordering scheme, the magnetic moments align in the 001 direction, antiparallel to their nearest neighbors. We have also performed variable-temperature electrical conductivity studies on these materials in the temperature range 298-1073 K. These studies have revealed the transformation of charge transport properties, where the metallic behavior of the Sr 2 compound is converted into semiconductivity in the CaSr material. The trend of conductivity as a function of temperature is reversed upon changing the A-site cation. The conductivity of the Sr 2 compound shows a downturn, while the conductivity of the CaSr material increases as a function of temperature. We have also shown that the CaSr compound exhibits temperature-dependent behavior typical of a mixed ionic-electronic conducting

  16. Sr isotope tracing of multiple water sources in a complex river system, Noteć River, central Poland

    Energy Technology Data Exchange (ETDEWEB)

    Zieliński, Mateusz, E-mail: mateusz.zielinski@amu.edu.pl [Institute of Geoecology and Geoinformation, Adam Mickiewicz University, Dzięgielowa 27, 61-680 Poznań (Poland); Dopieralska, Jolanta, E-mail: dopieralska@amu.edu.pl [Poznań Science and Technology Park, Adam Mickiewicz University Foundation, Rubież 46, 61-612 Poznań (Poland); Belka, Zdzislaw, E-mail: zbelka@amu.edu.pl [Isotope Laboratory, Adam Mickiewicz University, Dzięgielowa 27, 61-680 Poznań (Poland); Walczak, Aleksandra, E-mail: awalczak@amu.edu.pl [Isotope Laboratory, Adam Mickiewicz University, Dzięgielowa 27, 61-680 Poznań (Poland); Siepak, Marcin, E-mail: siep@amu.edu.pl [Institute of Geology, Adam Mickiewicz University, Maków Polnych 16, 61-606 Poznań (Poland); Jakubowicz, Michal, E-mail: mjakub@amu.edu.pl [Institute of Geoecology and Geoinformation, Adam Mickiewicz University, Dzięgielowa 27, 61-680 Poznań (Poland)

    2016-04-01

    Anthropogenic impact on surface waters and other elements in the environment was investigated in the Noteć River basin in central Poland. The approach was to trace changes in the Sr isotope composition ({sup 87}Sr/{sup 86}Sr) and concentration in space and time. Systematic sampling of the river water shows a very wide range of {sup 87}Sr/{sup 86}Sr ratios, from 0.7089 to 0.7127. This strong variation, however, is restricted to the upper course of the river, whereas the water in the lower course typically shows {sup 87}Sr/{sup 86}Sr values around 0.7104–0.7105. Variations in {sup 87}Sr/{sup 86}Sr are associated with a wide range of Sr concentrations, from 0.14 to 1.32 mg/L. We find that strong variations in {sup 87}Sr/{sup 86}Sr and Sr concentrations can be accounted for by mixing of two end-members: 1) atmospheric waters charged with Sr from the near-surface weathering and wash-out of Quaternary glaciogenic deposits, and 2) waters introduced into the river from an open pit lignite mine. The first reservoir is characterized by a low Sr content and high {sup 87}Sr/{sup 86}Sr ratios, whereas mine waters display opposite characteristics. Anthropogenic pollution is also induced by extensive use of fertilizers which constitute the third source of Sr in the environment. The study has an important implication for future archeological studies in the region. It shows that the present-day Sr isotope signatures of river water, flora and fauna cannot be used unambiguously to determine the “baseline” for bioavailable {sup 87}Sr/{sup 86}Sr in the past. - Highlights: • Sr isotopes fingerprint water sources and their interactions in a complex river system. • Mine waters and fertilizers are critical anthropogenic additions in the river water. • Limited usage of environmental isotopic data in archeological studies. • Sr budget of the river is dynamic and temporary.

  17. Method-of-use study of naltrexone sustained release (SR)/bupropion SR on body weight in individuals with obesity.

    Science.gov (United States)

    Halseth, Amy; Shan, Kevin; Walsh, Brandon; Gilder, Kye; Fujioka, Ken

    2017-02-01

    This study assessed the effects of 32 mg naltrexone sustained release (SR)/360 mg bupropion SR (NB) on body weight in adults with obesity, with comprehensive lifestyle intervention (CLI), for 78 weeks. In this phase 3b, randomized, open-label, controlled study, subjects received NB + CLI or usual care (standard diet/exercise advice) for 26 weeks. NB subjects not achieving 5% weight loss at week 16 were discontinued, as indicated by product labeling. After week 26, usual care subjects began NB + CLI. Assessments continued through week 78. The primary end point was percent change in weight from baseline to week 26 in the per protocol population. Other end points included percentage of subjects achieving ≥5%, ≥10%, and ≥15% weight loss, percent change in weight at week 78, and adverse events (AEs) necessitating study medication discontinuation. NB + CLI subjects lost significantly more weight than usual care subjects at week 26 (8.52% difference; P Weight loss persisted through 78 weeks. In total, 20.7% of subjects discontinued medication for AEs, including 7.0% for nausea. Treatment with NB, used as indicated by prescribing information and with CLI, significantly improved weight loss over usual care alone. NB-facilitated weight loss was sustained for 78 weeks and was deemed safe and well tolerated. © 2016 The Authors. Obesity published by Wiley Periodicals, Inc. onbehalf of The Obesity Society (TOS).

  18. Sorption of U(VI) in surfaces of SrTiO{sub 3}; Sorcion de U(VI) en superficies de SrTiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz O, H.B.; Ordonez R, E.; Fernandez V, S.M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2004-07-01

    In this work is presented the physico chemical characterization and evaluation of those surface properties and of sorption of U on the SrTiO{sub 3} like possible candidate for contention barrier in the deep geological confinement. The made studies showed that the SrTiO{sub 3} presents maximum levels of sorption of positive nature species (mainly UO{sub 2}{sup 2+} and UO{sub 2}NO{sub 3}{sup +}). (Author)

  19. Assessing response of local moisture conditions in central Brazil to variability in regional monsoon intensity using speleothem 87Sr/86Sr values

    Science.gov (United States)

    Wortham, Barbara E.; Wong, Corinne I.; Silva, Lucas C. R.; McGee, David; Montañez, Isabel P.; Troy Rasbury, E.; Cooper, Kari M.; Sharp, Warren D.; Glessner, Justin J. G.; Santos, Roberto V.

    2017-04-01

    Delineating the controls on hydroclimate throughout Brazil is essential to assessing potential impact of global climate change on water resources and biogeography. An increasing number of monsoon reconstructions from δ18O records provide insight into variations in regional monsoon intensity over the last millennium. The strength, however, of δ18O as a proxy of regional climate limits its ability to reflect local conditions, highlighting the need for comparable reconstructions of local moisture conditions. Here, speleothem 87Sr/86Sr values are developed as a paleo-moisture proxy in central Brazil to complement existing δ18O-based reconstructions of regional monsoon intensity. Speleothem 87Sr/86Sr values are resolved using laser ablation and conventional solution mass spectrometry at high resolution relative to existing (non-δ18O-based) paleo-moisture reconstructions to allow comparisons of centennial variability in paleo-monsoon intensity and paleo-moisture conditions. Variations in speleothem 87Sr/86Sr values from Tamboril Cave are interpreted to reflect varying extents of water interaction with the carbonate host rock, with more interaction resulting in greater evolution of water isotope values from those initially acquired from the soil to those of the carbonate bedrock. Increasing speleothem 87Sr/86Sr values over the last millennium suggest progressively less interaction with the carbonate host rock likely resulting from higher infiltration rates, expected under wetter conditions. Increasingly wetter conditions over the last millennium are consistent with an overall trend of increasing monsoon intensity (decreasing δ18O values) preserved in many existing δ18O records from the region. Such a trend, however, is absent in δ18O records from our site (central Brazil) and Cristal Cave (southeast Brazil), suggesting the existence of divergent (relevant to δ18Oprecip) shifts in the climate patterns within and outside the core monsoon region.

  20. Development and characterisation of a new Sr selective resin for the rapid determination of ⁹⁰Sr in environmental water samples.

    Science.gov (United States)

    Surman, J J; Pates, J M; Zhang, H; Happel, S

    2014-11-01

    A new resin selective for Sr has been developed and characterised for the direct binding of (90)Sr from environmental waters with minimal pre-treatment. The new selective resin comprises of a mixture of two extractants, 4,4'(5')-bis-t-butylcyclohexano-18-crown-6 and di(2-ethyl-hexyl)phosphoric acid, sorbed onto Amberchrom CG-71. Sr uptake is shown to be high (the distribution weight coefficient Dw >100 mL g(-1)) across a range of environmentally realistic conditions (pH 2-8 and up to 11,500 mg L(-1) NaCl, 500 mg L(-1) Ca, 400 mg L(-1) K and 1300 mg L(-1) Mg). The Sr capacity of the resin is shown to be 7.7±0.4 mg g(-1), meaning that the resin has a sufficient capacity to quantitatively remove Sr from most environmental water samples. The reasonably fast uptake kinetics of the resin (95±4% of strontium bound within 30 min) results in a resin that is applicable to both batch- and column-type separation procedures. A range of potentially co-extracted radio-elements have been identified and an elution scheme has been developed to separate interferences, including (90)Y, from (90)Sr. The clean elution of (90)Sr permits immediate measurement by radiometric means, with no need for complicated spectral processing or waiting for secular equilibrium between (90)Sr and (90)Y. The characterised resin is applicable for use in rapid determination procedures, enabling the swift analysis of water samples required by monitoring schemes at contaminated nuclear sites and in the aftermath of nuclear accidents. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Field Research Facility Data Integration Framework Data Management Plan: Survey Lines Dataset

    Science.gov (United States)

    2016-08-01

    ER D C/ CH L SR -1 6- 4 Coastal Ocean Data Systems Program Field Research Facility Data Integration Framework Data Management Plan...Systems Program ERDC/CHL SR-16-4 August 2016 Field Research Facility Data Integration Framework Data Management Plan Survey Lines Dataset Michael F...TITLE AND SUBTITLE Field Research Facility Data Integration Framework Data Management Plan: Survey Lines Dataset 5a. CONTRACT NUMBER 5b. GRANT NUMBER

  2. Experimentally determined biomediated Sr partition coefficient for dolomite : Significance and implication for natural dolomite

    NARCIS (Netherlands)

    Sánchez-Román, Mónica; McKenzie, Judith A.; de Luca Rebello Wagener, Angela; Romanek, Christopher S.; Sánchez-Navas, Antonio; Vasconcelos, Crisógono

    2011-01-01

    Two strains of moderately halophilic bacteria were grown in aerobic culture experiments containing gel medium to determine the Sr partition coefficient between dolomite and the medium from which it precipitates at 15 to 45°C. The results demonstrate that Sr incorporation in dolomite does occur not

  3. Comparison of histomorphometry and 85Sr uptake in induced heterotopic bone in rats

    DEFF Research Database (Denmark)

    Solheim, E; Pinholt, E M; Bang, G

    1992-01-01

    Heterotopic bone formation in the abdominal muscle of 45 male 8-week-old Wistar rats induced by implantation of 5, 10, or 15 mg demineralized bone (DBM) powder was evaluated at 4 weeks by 85Sr uptake of the implants and area histomorphometry of the induced bone. Two indices of 85Sr uptake were ca...

  4. Level and distribution of artificial radionuclides ({sup 90}Sr and {sup 137}Cs) in environment

    Energy Technology Data Exchange (ETDEWEB)

    Fukushima, Hiroto [Japan Chemical Analysis Center, Chiba (Japan)

    1998-05-01

    Chief artificial radionuclides deposited in the earth are {sup 90}Sr, {sup 137}Cs, {sup 239}Pu and {sup 240}Pu. These radionuclides have been reduced and dispersed depend on no nuclear test in atmosphere since 1981. {sup 137}Cs internal exposure was 22 and 0.5 {mu}Sv/y in 1964 and 1990, respectively. The concentration of {sup 90}Sr and {sup 137}Cs were determined in the samples in environment such as light dust, soil, river water, sea water, agricultural products, fish and sea grass from 1974 to 1996. The concentrations of {sup 90}Sr were 0.001 mBq/m{sup 3} or less in light dust, 0.05 MBq/km{sup 2} in deposit, 0.02-20 Bq/kg in soil, 0-5 mBq/liter in river water and not detected in fish body. The concentration of {sup 137}Cs was 0.2-100 Bq/kg in soil, 1 Bq/kg in agricultural products, 0.1 Bq/kg in fish and 0.03 Bq/kg in shell. {sup 90}Sr is supplied by soil and sea water. {sup 90}Sr accumulation is changed by geographical features, depth and soil. However, in the sea, the concentration of Sr (about 8 mBq/liter) was the same as that of {sup 90}Sr (about 2 mBq/liter). Sea grass contains the large concentration of {sup 90}Sr. (S.Y.)

  5. Factors controlling phase formation of novel Sr-based Y-type ...

    Indian Academy of Sciences (India)

    2017-01-04

    Jan 4, 2017 ... Fourier transform infrared spectroscopy (FTIR) studies revealed the information about the positions of the ions and their bonds within the lattice structure of the Sr2Y. The chemical elements and their oxidation states in the Sr2Y hexaferrites were determined using X-ray photoelectron spectroscopy (XPS).

  6. Progress of (Sr, Ba) TiO3 ferroelectric thin film and tunability

    Indian Academy of Sciences (India)

    Unknown

    The studies on (Ba, Sr) TiO3 microstructure concentrate on the crystal structure system, grain size distribution, domain structure, layers of regions, Curie temperature, growth mechanism of grain, lattice mismatch, strain and the influence of dopants on structure and performance etc. (Sr, Ba) TiO3 crystal exists as a cube and a ...

  7. Twentieth century warming of the tropical Atlantic captured by Sr-U paleothermometry

    Science.gov (United States)

    Alpert, Alice E.; Cohen, Anne L.; Oppo, Delia W.; DeCarlo, Thomas M.; Gaetani, Glenn A.; Hernandez-Delgado, Edwin A.; Winter, Amos; Gonneea, Meagan

    2017-01-01

    Coral skeletons are valuable archives of past ocean conditions. However, interpretation of coral paleotemperature records is confounded by uncertainties associated with single-element ratio thermometers, including Sr/Ca. A new approach, Sr-U, uses U/Ca to constrain the influence of Rayleigh fractionation on Sr/Ca. Here we build on the initial Pacific Porites Sr-U calibration to include multiple Atlantic and Pacific coral genera from multiple coral reef locations spanning a temperature range of 23.15–30.12°C. Accounting for the wintertime growth cessation of one Bermuda coral, we show that Sr-U is strongly correlated with the average water temperature at each location (r2 = 0.91, P Mean Sr-U temperatures and patterns of multiyear variability were replicated in a second coral in the same grid box. Conversely, Sr/Ca records from the same two corals were inconsistent with each other and failed to capture absolute sea temperatures, timing of multiyear variability, or the twentieth century warming trend. Our results suggest that coral Sr-U paleothermometry is a promising new tool for reconstruction of past ocean temperatures.

  8. Muscle Glycogen Content Modifies SR Ca2 + Release Rate in Elite Endurance Athletes

    DEFF Research Database (Denmark)

    Gejl, Kasper Degn; Hvid, Lars G; Frandsen, Ulrik

    2014-01-01

    The aim of the present study was to investigate the influence of muscle glycogen content on sarcoplasmic reticulum (SR) function and peak power output (Wpeak) in elite endurance athletes.......The aim of the present study was to investigate the influence of muscle glycogen content on sarcoplasmic reticulum (SR) function and peak power output (Wpeak) in elite endurance athletes....

  9. Promoting Photocatalytic Overall Water Splitting by Controlled Magnesium Incorporation in SrTiO3 Photocatalysts

    NARCIS (Netherlands)

    Han, Kai; Lin, Yen Chun; Yang, Chia Min; Jong, Ronald; Mul, Guido; Mei, Bastian

    2017-01-01

    SrTiO3 is a well-known photocatalyst inducing overall water splitting when exposed to UV irradiation of wavelengths <370 nm. However, the apparent quantum efficiency of SrTiO3 is typically low, even when functionalized with nanoparticles of Pt or Ni@NiO. Here, we introduce a simple solid-state

  10. Bupropion SR in Adolescents with Comorbid ADHD and Nicotine Dependence: A Pilot Study

    Science.gov (United States)

    Upadhyaya, Himanshu P.; Brady, Kathleen T.; Wang, Wei

    2004-01-01

    Objective: Bupropion SR has been shown to be effective for the treatment of nicotine dependence in adults. This open-label pilot study was designed to examine the feasibility and preliminary tolerability of bupropion SR in adolescents with nicotine dependence. Method: Sixteen adolescents aged 12 to 19 years were enrolled in the study. Eleven of…

  11. Epitaxial growth of solution deposited Bi2Sr2CaCu2Ox films

    NARCIS (Netherlands)

    Gobel, OF; Du, [No Value; Hibma, T; von Lampe, [No Value; Steiner, U

    The epitaxial growth of Bi2Sr2CaCu2Ox (Bi2212) high temperature superconducting thin films was studied. The films were solution-deposited from a polymer-containing precursor onto SrTiO3 (001) substrates. Bi2212 formed an epitaxial phase with the c-axis parallel to the substrate normal and an in-lane

  12. Factors controlling phase formation of novel Sr-based Y-type ...

    Indian Academy of Sciences (India)

    Fourier transform infrared spectroscopy (FTIR) studies revealed the information about the positions of the ions and their bonds within the lattice structure of the Sr2Y. The chemical elements and their oxidation states in the Sr 2 Y hexaferriteswere determined using X-ray photoelectron spectroscopy (XPS). The XRD, FTIR and ...

  13. 40 CFR 721.10008 - Manganese strontium oxide (MnSrO3).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Manganese strontium oxide (MnSrO3... Specific Chemical Substances § 721.10008 Manganese strontium oxide (MnSrO3). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as manganese strontium oxide...

  14. Corrosion resistance and biocompatibility of SrHAp/ZnO composite implant coating on titanium

    Science.gov (United States)

    Huang, Yong; Zeng, Hongjuan; Wang, Xuexin; Wang, Deshun

    2014-01-01

    The corrosion resistance of electrodeposited ZnO containing and strontium doped hydroxyapatite (SrHAp/ZnO) coating on titanium (Ti) substrate was investigated. The microstructure, phase composition and corrosion resistance of the coating were studied. The results reveal that Sr2+ and ZnO incorporation markedly increased the density of HAp coating, i.e. the fabricated coating had significantly lower porosity than the original HAp coating. The SrHAp/ZnO coating was dense and uniform, with a flocculent morphological structure of apatite. The SrHAp/ZnO crystals were carbonated calcium-deficient hydroxyapatite, and Sr2+ and ZnO were homogeneously distributed in the coating. The thickness of the composite coating was almost 10 μm without delamination or cracks at the interface. Bond strength test revealed that the adhesion of the SrHAp/ZnO coating was more enhanced than that of the HAp coating. The SrHAp/ZnO-coated Ti had a lower corrosion rate than the pure HAp-coated sample, which suggests the protective characteristic of the composite coating. Osteoblast cellular tests demonstrated that the SrHAp/ZnO composite coating greatly enhanced the in vitro biocompatibility of the Ti substrate.

  15. The ternary post-transition metal carbodiimide SrZn(NCN){sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Corkett, Alex J.; Konze, Philipp M. [Institute of Inorganic Chemistry, RWTH Aachen University, Aachen (Germany); Dronskowski, Richard [Institute of Inorganic Chemistry, RWTH Aachen University, Aachen (Germany); Juelich-Aachen Research Alliance (JARA-HPC), RWTH-Aachen University, Aachen (Germany)

    2017-11-17

    SrZn(NCN){sub 2}, the first example of a ternary post-transition metal carbodiimide, was prepared by a solid-state metathesis reaction. The crystal structure was solved from PXRD data and found to adopt the orthorhombic (Cmcm) BaZnSO structure, a high symmetry modification of that expressed by the oxide analogue SrZnO{sub 2}. Locally, SrZn(NCN){sub 2} features ZnN{sub 4} tetrahedra and SrN{sub 6} trigonal prisms similar to those in quarternary LiSr{sub 2}M(NCN){sub 4} (M = Al{sup 3+} and Ga{sup 3+}) phases, however, the overall topologies are distinct with single chains in the former and double chains in the latter. Electronic structure calculations indicate an indirect bandgap of about 2.95 eV in SrZn(NCN){sub 2}, slightly lower than the experimentally observed bandgap of 3.4 eV in SrZnO{sub 2} and consistent with a greater degree of covalency. The structural similarities between SrZn(NCN){sub 2} and oxychalcogenide analogues highlight the pseudochalcogenide character of NCN{sup 2-} and suggest that the title compound may serve as a template for accessing novel ternary carbodiimides featuring tetrahedrally coordinated transition metals. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Strong kinetic effects on Sr/Ca ratios in the calcitic bivalve Pecten maximus

    Science.gov (United States)

    Lorrain, Anne; Gillikin, David P.; Paulet, Yves-Marie; Chauvaud, Laurent; Le Mercier, Alain; Navez, Jacques; André, Luc

    2005-12-01

    Although Sr/Ca ratios in abiogenic calcite are strongly controlled by precipitation rates, such a kinetic effect has never been demonstrated in calcitic bivalve shells. Therefore, we report Sr/Ca ratios together with daily growth rates in the calcitic shells of four individuals of the bivalve Pecten maximus (age class I). Ratios of Sr/Ca were found to be variable among individuals that grew at the same location, illustrating that vital effects dominate over environmental controls. Although daily growth rate was correlated with shell Sr/Ca ratios, it explained only half of the Sr/Ca variations. However, daily shell surface area increment, an estimation of the total quantity of carbonate precipitated for a given time, explained 74% of the Sr/Ca variability in the shells of P. maximus. This proves, for the first time in a calcitic bivalve, that shell Sr/Ca partitioning is mainly controlled by kinetic effects. The Sr/Ca ratio should therefore be tested as a potential proxy of calcification rate in modern or fossil calcitic biocarbonates.

  17. Removal of radionuclide Sr{sup 2+} ions from aqueous solution using synthesized magnetic chitosan beads

    Energy Technology Data Exchange (ETDEWEB)

    Chen Yuwei [Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084 (China); Wang Jianlong, E-mail: wangjl@tsinghua.edu.cn [Laboratory of Environmental Technology, INET, Tsinghua University, Beijing 100084 (China); Beijing Key Laboratory of Fine Ceramics, INET, Tsinghua University, Beijing 100084 (China)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer A novel magnetic chitosan beads were prepared and applied for removing Sr{sup 2+}. Black-Right-Pointing-Pointer The maximum adsorption capacity (q{sub m}) of Sr{sup 2+} was calculated to be 11.58 mg/g using the Langmuir isotherm. Black-Right-Pointing-Pointer The FT-IR study revealed that -NH{sub 2} was mainly involved in Sr{sup 2+} sorption. - Abstract: Strontium-90 is one of the main fission products, existing in the radioactive wastes produced in nuclear power plant. In this paper, a novel magnetic chitosan beads were synthesized, characterized and applied for removal of Sr{sup 2+} ions from aqueous solution. The SEM analysis indicated that the magnetic beads were in regular spherical geometry with about 1 mm diameter. The XRD and EDS analysis revealed that the chitosan beads were magnetic and can be used for the magnetic separation. The influencing factors of Sr{sup 2+} sorption onto magnetic chitosan beads were studied, including contact time, initial pH value, initial Sr{sup 2+}concentration and sorbent dosage. The maximum adsorption capacity (q{sub m}) of Sr{sup 2+} was calculated to be 11.58 mg/g using the Langmuir isotherm. The kinetic data were analyzed by intra particle diffusion model. The FT-IR study revealed that -NH{sub 2} was mainly involved in Sr{sup 2+} sorption by magnetic chitosan beads.

  18. A solidification model for unmodified, Na-modified and Sr-modified Al-Si alloys

    DEFF Research Database (Denmark)

    Tiedje, Niels Skat; Hattel, Jesper Henri; Taylor, J. A.

    2012-01-01

    An addition of small amounts of Na and Sr is commonly used in the industry to modify the eutectic in Al-Si alloys. Both Na and Sr suppress nucleation of the eutectic forcing nucleation and growth to take place at higher undercooling than in the unmodified material. Thus the scale of the eutectic ...

  19. Photocatalytic reduction synthesis of SrTiO3-graphene nanocomposites and their enhanced photocatalytic activity.

    Science.gov (United States)

    Xian, Tao; Yang, Hua; Di, Lijing; Ma, Jinyuan; Zhang, Haimin; Dai, Jianfeng

    2014-01-01

    SrTiO3-graphene nanocomposites were prepared via photocatalytic reduction of graphene oxide by UV light-irradiated SrTiO3 nanoparticles. Fourier transformed infrared spectroscopy analysis indicates that graphene oxide is reduced into graphene. Transmission electron microscope observation shows that SrTiO3 nanoparticles are well assembled onto graphene sheets. The photocatalytic activity of as-prepared SrTiO3-graphene composites was evaluated by the degradation of acid orange 7 (AO7) under a 254-nm UV irradiation, revealing that the composites exhibit significantly enhanced photocatalytic activity compared to the bare SrTiO3 nanoparticles. This can be explained by the fact that photogenerated electrons are captured by graphene, leading to an increased separation and availability of electrons and holes for the photocatalytic reaction. Hydroxyl (·OH) radicals were detected by the photoluminescence technique using terephthalic acid as a probe molecule and were found to be produced over the irradiated SrTiO3 nanoparticles and SrTiO3-graphene composites; especially, an enhanced yield is observed for the latter. The influence of ethanol, KI, and N2 on the photocatalytic efficiency was also investigated. Based on the experimental results, ·OH, h(+), and H2O2 are suggested to be the main active species in the photocatalytic degradation of AO7 by SrTiO3-graphene composites. 61.46. + w; 78.67.Bf; 78.66.Sq.

  20. Fuel and canister process report for the safety assessment SR-Site

    Energy Technology Data Exchange (ETDEWEB)

    Werme, Lars; Lilja, Christina (eds.)

    2010-12-15

    This report documents fuel and canister processes identified as relevant to the long-term safety of a KBS-3 repository. It forms an important part of the reporting of the safety assessment SR-Site. The detailed assessment methodology, including the role of the process reports in the assessment, is described in the SR-Site Main report /SKB 2011/

  1. Transportin-SR is required for proper splicing of resistance genes and plant immunity.

    Directory of Open Access Journals (Sweden)

    Shaohua Xu

    2011-06-01

    Full Text Available Transportin-SR (TRN-SR is a member of the importin-β super-family that functions as the nuclear import receptor for serine-arginine rich (SR proteins, which play diverse roles in RNA metabolism. Here we report the identification and cloning of mos14 (modifier of snc1-1, 14, a mutation that suppresses the immune responses conditioned by the auto-activated Resistance (R protein snc1 (suppressor of npr1-1, constitutive 1. MOS14 encodes a nuclear protein with high similarity to previously characterized TRN-SR proteins in animals. Yeast two-hybrid assays showed that MOS14 interacts with AtRAN1 via its N-terminus and SR proteins via its C-terminus. In mos14-1, localization of several SR proteins to the nucleus was impaired, confirming that MOS14 functions as a TRN-SR. The mos14-1 mutation results in altered splicing patterns of SNC1 and another R gene RPS4 and compromised resistance mediated by snc1 and RPS4, suggesting that nuclear import of SR proteins by MOS14 is required for proper splicing of these two R genes and is important for their functions in plant immunity.

  2. Josephson effect in a multiorbital model for Sr2RuO4

    NARCIS (Netherlands)

    Kawai, K.; Yada, Keiji; Tanaka, Y.; Asano, Y.; Golubov, Alexandre Avraamovitch; Kashiwaya, S.

    2017-01-01

    We study Josephson currents between s-wave/spin-triplet superconductor junctions by taking into account details of the band structures in Sr2RuO4, such as three conduction bands and spin-orbit interactions in the bulk and at the interface. We assume five superconducting order parameters in Sr2RuO4:

  3. First records of three species of Oxycraspedus Kuschel (Coleóptera: Belidae in Argentina and use of a predictive model to compare their potential distribution with the range of their host-plant, Araucaria araucana Primera cita de las tres especies de Oxycraspedus Kuschel (Coleóptera: Belidae en Argentina y uso de un modelo predictivo para comparar su distribución potencial con el rango de su planta huésped, la Araucaria araucana

    Directory of Open Access Journals (Sweden)

    M.S. FERRER

    2007-09-01

    Full Text Available The first records of the three known species of Oxycraspedus Kuschel (Belidae: Oxycoryninae in Argentina are reported, and added to their known distribution in Chile. These weevils are of interest because of their association with the pehuén or monkey puzzle tree, Araucaria araucana, a species of conservation concern. Their distribution data are of value for the protection of biodiversity in natural areas of Patagonia. The potential distribution of Oxycraspedus, as predicted by a model using bioclimatic variables, is coincident as expected, with the geographic range of the araucaria host-plantSe reportan por primera vez en Argentina las tres especies de Oxycraspedus Kuschel (Belidae: Oxycoryninae y se añaden a su distribución en Chile. Estos gorgojos son de interés debido a su asociación con el pehuén Araucaria araucana, una especie de gran interés en temas de conservación. Los datos sobre su distribución son valiosos para proteger la biodiversidad en áreas de la Patagonia. La distribución potencial de Oxycraspedus predicha por un modelo a partir de variables bioclimáticas, es coincidente, como se esperaba, con el rango geográfico de su planta huésped, la araucaria

  4. Deducing the source and composition of rare earth mineralising fluids in carbonatites: insights from isotopic (C, O, 87Sr/86Sr) data from Kangankunde, Malawi

    Science.gov (United States)

    Broom-Fendley, Sam; Wall, Frances; Spiro, Baruch; Ullmann, Clemens V.

    2017-12-01

    Carbonatites host some of the largest and highest grade rare earth element (REE) deposits but the composition and source of their REE-mineralising fluids remains enigmatic. Using C, O and 87Sr/86Sr isotope data together with major and trace element compositions for the REE-rich Kangankunde carbonatite (Malawi), we show that the commonly observed, dark brown, Fe-rich carbonatite that hosts REE minerals in many carbonatites is decoupled from the REE mineral assemblage. REE-rich ferroan dolomite carbonatites, containing 8-15 wt% REE2O3, comprise assemblages of monazite-(Ce), strontianite and baryte forming hexagonal pseudomorphs after probable burbankite. The 87Sr/86Sr values (0.70302-0.70307) affirm a carbonatitic origin for these pseudomorph-forming fluids. Carbon and oxygen isotope ratios of strontianite, representing the REE mineral assemblage, indicate equilibrium between these assemblages and a carbonatite-derived, deuteric fluid between 250 and 400 °C (δ18O + 3 to + 5‰VSMOW and δ13C - 3.5 to - 3.2‰VPDB). In contrast, dolomite in the same samples has similar δ13C values but much higher δ18O, corresponding to increasing degrees of exchange with low-temperature fluids (dolomite carbonatite (beforsite: δ18O + 7.7 to + 10.3‰ and δ13C -5.2 to -6.0‰; 87Sr/86Sr 0.70296-0.70298) is not directly linked with the REE mineralisation.

  5. Solid state and magnetochemistry of the SrO-Fe2O3 system IV. Synthesis of SrFe12O19 from coprecipitated precursors

    Science.gov (United States)

    Qian, Xueyu; Evans, B. J.

    1981-03-01

    By means of 57Fe Mössbauer spectroscopy and powder x-ray diffraction techniques, it has been determined that the formation of SrFe12O19 from coprecipitated ferric hydroxide and strontium laurate follows a reaction mechanism different from that when SrCO3 and Fe2O3 are used as starting materials. Upon heating at 300 C in vacuum, strontium laurate decomposes and further heating to 550 C leads to the formation of γ-Fe2O3 from the ferric hydroxide and solid solution of SrO in γ-Fe2O3. This solid solution phase behaves as an intermediate and undergoes further reaction with γ-Fe2O3 to give SrFe12O19. No paramagnetic Sr-Fe oxide intermediate is formed. The low temperature of the reactions and the absence of paramagnetic intermediates offer new possibilities for controlling the textures and magnetic properties SrFe12O19 ceramic bodies.

  6. Methodological development for 87Sr/86Sr measurement in olive oil and preliminary discussion of its use for geographical traceability of PDO Nîmes (France).

    Science.gov (United States)

    Medini, Salim; Janin, Myriam; Verdoux, Patrick; Techer, Isabelle

    2015-03-15

    The lack of a geographical identification protocol for olive oils can lead to fraud and health risks. As some works call for Sr isotopes for the geographical identification of agri-food products, this study focus on the feasibility of extracting Sr from olive oils for isotopic measurements by TIMS. In fact, existing protocols for purification of Sr are unsuitable for lipid matrix. The defined protocol is applied to samples of PDO Nîmes olive oil. The accuracy of the extraction procedure is tested against isotopic standards. The values obtained are in conformity with NIST certified values. This consistency demonstrates that no modification of (87)Sr/(86)Sr ratio is brought about by this protocol. Consequently, the method is preliminary used on PDO Nîmes and Moroccan oils to evaluate the feasibility of a discriminant Sr signature on the two geographical products. This study provides promising results for the geographical discrimination and identification of PDO olive oils. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Antiferromagnetic and xy ferro-orbital order in insulating SrRuO3 thin films with SrO termination

    Science.gov (United States)

    Autieri, C.

    2016-10-01

    By means of first-principles calculations we study the structural, magnetic and electronic properties of SrRuO3 surface for the SrO termination. We find that the RuO6 octahedra and the structure of the SrO layers at the surface are strongly modified as well as the Ru-O-Ru bond angles. We find in the thin films a d xy ferro-orbital order. The d xy orbital becomes the lowest in energy as in other quasitwodimensional ruthenates. Such structural rearrangement, together with a band reduction, leads to a modification of the magnetic properties. We compare the Jahn-Teller effect between the ferromagnetic and antiferromagnetic phases. We show that an insulating G-type antiferromagnetic phase takes place in SrRuO3 thin films, substituting the metallic phase experimentally found in every bulk Sr-ruthenates. The single layer SrRuO3 presents many similarities with the Ca2RuO4 low temperature phase, these similarities disappear with a larger number of layers. A study of the ground state of the as function of the number of layers is presented, the competition between bandwidth and Coulomb repulsion determines the ground state. We propose the disorder as responsible for the exchange bias effect observed.

  8. Review of SKB's Safety Assessment SR-Can: Contributions in Support of SKI's and SSI's Review by External Consultants

    Energy Technology Data Exchange (ETDEWEB)

    2008-03-15

    The Swedish Nuclear Fuel and Waste Management Co (SKB) plans to submit a license application for the construction of a repository for spent nuclear fuel in Sweden 2010. In support of this application SKB will present a safety report, SR-Site, on the repository's long-term safety and radiological consequences. As a preparation for SR-Site, SKB published the preliminary safety assessment SR-Can in November 2006. The purposes were to document a first evaluation of long-term safety for the two candidate sites at Forsmark and Laxemar and to provide feedback to SKB's future programme of work. An important objective of the authorities' review of SR-Can is to provide guidance to SKB on the complete safety reporting for the license application. The authorities have engaged external experts for independent modelling, analysis and review, with the aim to provide a range of expert opinions related to the sufficiency and appropriateness of various aspects of SR-Can. The conclusions and judgments in this report are those of the authors and may not necessarily coincide with those of SKI and SSI. The authorities own review will be published separately (SKI Report 2008:23, SSI Report 2008:04 E). This report compiles contributions from several specific research projects. The separate reviews cover topics regarding the engineered barrier system, the quality assurance, the climate evolution and its effects, and the ecosystems and environmental impacts. All contributions are in English apart from the review concerning ecosystems and environmental impacts, which is presented in Swedish

  9. Nonstoichiometry and stability in water of undoped SrCeO3

    Directory of Open Access Journals (Sweden)

    Jurado, J. R.

    2003-10-01

    Full Text Available Strontium cerate is the parent phase of an important class of proton-conducting perovskites with various potential technological applications. Phase formation and structure of SrCeO3 with Sr:Ce nonstoichiometry have been investigated for the series, Sr1±xCeO3±δ (0.98 ≤ x ≤ 1.04. Analyses by EPMA (electron probe micro analysis and X-ray diffraction (XRD indicate that, for samples sintered at 1350°C, the main phase is Sr-rich for all x. The accommodation of excess SrO in the bulk phase and/or intergranular regions is discussed. The stability of nominally stoichiometric SrCeO3 was examined in an atmosphere of high water vapour partial pressure (pH2O for 2 hours, degrading to Sr(OH2.H2O and CeO2 for pH2O ≥ 3.6atm.La fase SrCeO3 da origen a una importante familia de perovskitas conductoras protónicas con potenciales aplicaciones tecnológicas. En este trabajo se estudia la formación de la fase y la estructura de SrCeO3 con la relación Sr:Ce no estequiométrica para la serie Sr1±xCeO3±δ (0.98 ≤ x ≤ 1.04. Los análisis por microsonda (EPMA y difracción de rayos X (DRX indican que en las muestras sinterizadas a 1350°C, la fase principal es rica en estroncio para todo valor de x. Se discute la posible ubicación del exceso de SrO tanto en la región intergranular como en el propio grano. También se examina la estabilidad de la composición con estequiometría nominal SrCeO3 en una atmosfera con una alta presión de vapor de agua (pH2O, observándose que la degradación a Sr(OH2.H2O y CeO2 ocurre a pH2O ≥ 3.6atm (expuesto durante 2 horas.

  10. Synthesis of highly sinterable Yb: SrF2 nanopowders for transparent ceramics

    Science.gov (United States)

    Li, Weiwei; Huang, Haijun; Mei, Bingchu; Song, Jinghong

    2018-01-01

    In this paper, ytterbium doped strontium fluoride (Yb: SrF2) nanoparticles were synthesized by direct precipitation method. High-speed centrifugation was used to separate high sintering activity of nanopowders from powders with hard aggregated and large size. Using powders at different parts of the centrifugal tube as starting powders, Yb: SrF2 transparent ceramics was fabricated by hot pressed (HP) method for the first time. Effects of morphology and particle size on the sinterability of Yb: SrF2 nanopowders were investigated. The transmittance reached 77% at the wavelength of 1200 nm and pores stilled remained in the ceramics. The spectroscopic and thermal properties of Yb: SrF2 transparent ceramics were also investigated. This paper provides an effective way to obtain well dispersed and high sinterability nanoparticles for SrF2 ceramics sintering.

  11. Nonstoichiometry in Strontium Uranium Oxide: Understanding the Rhombohedral-Orthorhombic Transition in SrUO4.

    Science.gov (United States)

    Murphy, Gabriel L; Kennedy, Brendan J; Kimpton, Justin A; Gu, Qinfen; Johannessen, Bernt; Beridze, George; Kowalski, Piotr M; Bosbach, Dirk; Avdeev, Maxim; Zhang, Zhaoming

    2016-09-19

    In situ neutron and synchrotron X-ray diffraction studies demonstrate that SrUO4 acts as an oxygen transfer agent, forming oxygen vacancies under both oxidizing and reducing conditions. Two polymorphs of SrUO4 are stable at room temperature, and the transformation between these is observed to be associated with thermally regulated diffusion of oxygen ions, with partial reduction of the U(6+) playing a role in both the formation of oxygen deficient α-SrUO4-δ and its subsequent transformation to stoichiometric β-SrUO4. This is supported by ab initio calculations using density functional theory calculations. The oxygen vacancies play a critical role in the first order transition that SrUO4 undergoes near 830 °C. The changes in the oxidation states and U geometry associated with the structural phase transition have been characterized using X-ray absorption spectroscopy, synchrotron X-ray diffraction, and neutron diffraction.

  12. Effect of Sr Additive Amount and Holding Time on Microstructure of A390 Aluminum Alloy

    Science.gov (United States)

    Zhang, J. H.; Xing, S. M.; Han, Q. Y.; Guo, Q.; Wang, R. F.

    2017-11-01

    The microstructure of A390 alloy under different Sr additive amounts and holding times was studied by means of direct reading spectrum analysis, energy spectrum analysis, optical microscope and electron microscope. The results show that Sr has a good modification to eutectic Si, while it has a negative effect on primary silicon. The Sr addition will increase the size of primary silicon. When the addition amount of Al-10Sr alloy is 0.6%, the modification of eutectic silicon is the optimum. The Sr has a short incubation period and a fine modification at 10min, but it is more serious burning rate in small furnace smelting, and the modification effect disappears basically after 100min.

  13. Phase relations and conductivity of Sr-zirconates and La-zirconates

    DEFF Research Database (Denmark)

    Poulsen, F.W.; Vanderpuil, N.

    1992-01-01

    phase orthorhombic SrZrO3 and somewhat impure, tetragonal Sr2ZrO4 were observed, whereas the formation of ordered Ruddlesden-Popper phases, SrnZrn-1O3n-2, where n = 4 and 3, could not be verified. The conductivity of La2Zr2O7 was 3.7 X 10(-6) S/cm at 750-degrees-C and 3.8 x 10(-5) S/cm at 1000-degrees......-C. The conductivity of the Sr-zirconates increases with increasing Sr/Zr ratio. Samples with a nominal composition corresponding to Sr2ZrO4 have a conductivity of 7.5 x 10(-5) and 5.9 x 10(-4) S/cm at 750 and 1000-degrees-C, respectively. For all samples one observes low activation energies for ionic conduction (0...

  14. Optical Properties of Rare Earth Doped SrS Phosphor: A Review

    Science.gov (United States)

    Khare, Ayush; Mishra, Shubhra; Kshatri, D. S.; Tiwari, Sanjay

    2017-02-01

    Rare earth (RE) doped SrS phosphor has attracted a lot of attention on a wide range of photo-, cathodo-, thermo-, and electroluminescent applications. Upon doping with different RE elements (e.g., Ce, Pr, Eu, Yb), the luminescence from SrS can be varied over the entire visible region by appropriately choosing the composition of the strontium sulfide host. The main applications include flat panel displays and SrS-based powder electroluminescence (EL) for back lights. Sulfide materials known for providing Eu2+ based red emission band and preferred as a color conversion material in white light emitting diodes are discussed. Especially, the applications of RE doped SrS are described in light of their utility as conversion and storage phosphors. The effect of energy level splitting, EL efficiency, post-annealing, milling time, and impurity on luminescence properties for SrS are also discussed.

  15. Rapid screening of 90Sr activity in water and milk samples using Cherenkov radiation.

    Science.gov (United States)

    Stamoulis, K C; Ioannides, K G; Karamanis, D T; Patiris, D C

    2007-01-01

    A method for screening 90Sr in milk samples is proposed. This method is based on a liquid scintillation technique taking advantage of Cherenkov radiation, which is produced in a liquid medium and then detected by the photomultipliers of a Liquid Scintillation Counter (LSC). Twenty millilitres of water and milk samples spiked with various concentrations of 90Sr/90Y in equilibrium were added in plastic vials and then were measured with an LSC (TriCarb 3170 TR/SL). The derived efficiencies were 49% for water samples and 14% for milk samples. The detection limit was 470 mBq L(-1)(90)Sr for water, without any pretreatment. Milk contains potassium, which also produces Cherenkov radiation due to the presence of 40K. For this reason, the interference of 40K in the measurements of 90Sr in milk samples was also investigated. The detection limit for milk was 1.7 Bq L(-1)90Sr.

  16. Magneto-transport properties of La 0.7 Ca 0.3 MnO 3/SrTiO 3/La 0.7 ...

    Indian Academy of Sciences (India)

    La0.7Ce0.3MnO3/SrTiO3/La0.7Ce0.3MnO3 tunnel junction; magneto-transport properties; magnetoresistance. ... University of Birmingham, B15 2TT, UK; Institut fur Festkorper und Wekstofforschung, Dresden, D-01069 Dresden, Germany; Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India ...

  17. In memoriam: Robert Earl Stewart, Sr., 1913-1993

    Science.gov (United States)

    Robbins, Chandler S.; Meanley, M.B.

    1996-01-01

    Robert Earl Stewart, Sr., our colleague, close friend, and mentor, was born on 16 April 1913 in Kansas City, Missouri. He graduated from high school in Grimes, Iowa, received his B.S. in Biology from the University of Iowa in 1936, and his M.S. in Zoology from the University of Michigan in 1937. His post-graduate work on the life history of the Common Yellow throat was published in the Wilson Bulletin in 1953. Bob joined the AOU in 1938, was made an Elective Member in 1949, and a Fellow in 1974. During World War II, he served with the U.S. Navy Medical Corps in the Pacific Theater.

  18. Structure of normally deformed states in {sup 80}Sr

    Energy Technology Data Exchange (ETDEWEB)

    Winchell, D. F. [University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Wood, V. Q. [University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Saladin, J. X. [University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Birriel, I. [University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Baktash, C. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Brinkman, M. J. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Jin, H.-Q. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Rudolph, D. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Yu, C.-H. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Devlin, M. [Washington University, St. Louis, Missouri 63130 (United States)] (and others)

    2000-04-01

    High-spin states were populated in {sup 80}Sr with the reaction {sup 58}Ni({sup 28}Si,{alpha}2p), using a 130 MeV {sup 28}Si beam from the 88-Inch Cyclotron at LBNL. Gamma rays were detected with Gammasphere, and evaporated alphas and protons were detected with the Microball. The level scheme has been extended, and angular distributions of many of the transitions have been measured. A portion of the data was taken using a backed target, allowing lifetime measurements. No evidence for band termination was found in the spin range studied, but a cranking model analysis indicates possible shape evolution at higher spin. (c) 2000 The American Physical Society.

  19. Laser and Fourier transform spectroscopy of 7Li88Sr

    Science.gov (United States)

    Schwanke, Erik; Knöckel, Horst; Stein, Alexander; Pashov, Asen; Ospelkaus, Silke; Tiemann, Eberhard

    2017-12-01

    LiSr was produced in a heat-pipe oven and its thermal emission spectrum around 9300 cm‑1 was recorded by a high resolution Fourier transform spectrometer. In addition, selected lines of the spectrum of deeply bound vibrational levels of the {1}2{{{Σ }}}+ and {2}2{{{Σ }}}+ states were studied using laser excitation to facilitate the assignment of the lines. The ground state could be described for {v}{\\prime\\prime }=0 to 2, {N}{\\prime\\prime } up to 105 and the {2}2{{{Σ }}}+ state for {v}{\\prime }=0 up to {N}{\\prime }=68. For both states, Dunham coefficients, spin–rotation parameters and potential energy curves were evaluated. A coupling of the {2}2{{{Σ }}}+ state to the {1}2{{\\Pi }} state was observed, allowing a local description with Dunham coefficients of the {1}2{{\\Pi }} state and an approximate evaluation of the coupling strength.

  20. C41SR and Urban Disasters Disaster Response & Recovery Tools

    Energy Technology Data Exchange (ETDEWEB)

    Brouillette, Greg A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States). Risk Analysis and Decision Support Group

    2007-03-27

    These are slides for various presentations on C41SR and urban disasters disasters response and recovery tools. These are all mainly charts and images of disaster response and recovery tools. Slides included have headings such as the following: vignette of a disaster response, situational awareness and common operating picture available to EOC, plume modeling capability, Program ASPECT Chemical Response Products, EPA ASPECT - Hurricane RITA Response 9/25/2005, Angel Fire Imagery, incident commander's view/police chief's view/ EMS' view, common situational awareness and collaborative planning, exercise, training capability, systems diagram, Austere Challenge 06 Sim/C4 Requirements, common situational awareness and collaborative planning, exercise, training environment, common situational awareness, real world, crisis response, and consequence management.

  1. Heavy metal analysis in groundwater samples by SR-TXRF

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Silvana; Ficaris, Maria [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Civil, Arquitetura e Urbanismo. Dept. de Recursos Hidricos]. E-mail: silvana@fec.unicamp.br; Vives, Ana Elisa S. de [Universidade Metodista de Piracicaba (UNIMEP), Santa Barbara D' Oeste, SP (Brazil). Faculdade de Engenharia, Arquitetura e Urbanismo]. E-mail: aesvives@unimep.br; Zucchi, Orgheda L.A.D. [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Ciencias Farmaceuticas]. E-mail: olzucchi@fcfrp.usp.br; Nascimento Filho, Virgilio Franco do [Centro de Energia Nuclear na Agricultura (CENA), Piracicaba, SP (Brazil). Lab. Instrumentacao Nuclear]. E-mail: virgilio@cena.usp.br

    2005-07-01

    In order to obtain information about levels of heavy metals in groundwater, analysis were carried out on samples from monitoring and supplying wells located in Campinas, Sao Paulo State, Southeastern Brazil. The analytical technique used was Synchrotron Radiation Total Reflection X-Ray Fluorescence (SR-TXRF) and all the measurements were performed at Synchrotron Light Source Laboratory, using a white beam and a Si(Li) detector in total reflection condition. The determined elements were Al, Cr, Mn, Fe, Ni, Cu, Zn, Ba and Pb. The results were compared with the maximum allowed values (MPV) established by the Brazilian Health Department. The detection limits obtained varying from 0.10 up to 8 {mu}g.L{sup -1} were in agreement with the values presented by others analytical techniques. (author)

  2. Tunable cw UV laser with spectroscopy of Sr Rydberg states.

    Science.gov (United States)

    Bridge, Elizabeth M; Keegan, Niamh C; Bounds, Alistair D; Boddy, Danielle; Sadler, Daniel P; Jones, Matthew P A

    2016-02-08

    We present a solid-state laser system that generates over 200 mW of continuous-wave, narrowband light, tunable from 316.3 nm - 317.7 nm and 318.0 nm - 319.3 nm. The laser is based on commercially available fiber amplifiers and optical frequency doubling technology, along with sum frequency generation in a periodically poled stoichiometric lithium tantalate crystal. The laser frequency is stabilized to an atomic-referenced high finesse optical transfer cavity. Using a GPS-referenced optical frequency comb we measure a long term frequency instability of spectroscopy of Sr Rydberg states from n = 37 - 81, demonstrating mode-hop-free scans of 24 GHz. In a cold atomic sample we measure Doppler-limited linewidths of 350 kHz.

  3. Sr isotopic composition of hydroxyapatite from recent and fossil salmon: the record of lifetime migration and diagenesis

    Science.gov (United States)

    Koch, Paul L.; Halliday, Alex N.; Walter, Lynn M.; Stearley, Ralph F.; Huston, Ted J.; Smith, Gerald R.

    1992-02-01

    By comparing the Sr isotopic composition of migratory fossil salmon, which lived in the ocean but died in continental regions, to the well established marine Sr isotopic record, the age of the continental deposit could be determined with high accuracy. This approach to marine-continental correlation and dating requires (1) that marine-resident salmon bear a marine 87Sr/ 86Sr value in their bones or teeth, and (2) that the original 87Sr/ 86Sr value of fossils is not overprinted by diagenesis. The vertebrae of modern, hatchery-reared salmon exhibit Sr isotopic variations indicative of freshwater to marine migration during bone growth. Modern marine 87Sr/ 86Sr values were preserved in growth layers formed later in life. Marine-phase growth layers in the bones and teeth of the late Miocene migratory salmon, Oncorhynchus rastrosus, were subjected to stepwise selective leaching to separate biogenic hydroxyapatite from diagenetic calcium carbonate and recrystallized hydroxyapatite. Although the procedure yielded leachates with Sr/Ca and Ca/P values characteristic of apatite, the leachates had 87Sr/ 86Sr values consistently less radiogenic than values for late Miocene seawater ( ⊃ 0.7087. The fossils were substantially contaminated by Sr from the hosting clastic sediments. Specimens in continental deposits differed in 87Sr/ 86Sr value from host sediments by 0.0002 to 0.0200, supporting the conclusion that these salmon were migrants from marine waters. However, because the original Sr isotopic composition of fossil bones and teeth cannot be determined with confidence, archaeological, paleobiological and stratigraphic applications of this technique may be limited.

  4. Splicing factor SR34b mutation reduces cadmium tolerance in Arabidopsis by regulating iron-regulated transporter 1 gene

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wentao; Du, Bojing; Liu, Di; Qi, Xiaoting, E-mail: qixiaoting@cnu.edu.cn

    2014-12-12

    Highlights: • Arabidopsis splicing factor SR34b gene is cadmium-inducible. • SR34b T-DNA insertion mutant is sensitive to cadmium due to high cadmium uptake. • SR34b is a regulator of cadmium transporter IRT1 at the posttranscription level. • These results highlight the roles of splicing factors in cadmium tolerance of plant. - Abstract: Serine/arginine-rich (SR) proteins are important splicing factors. However, the biological functions of plant SR proteins remain unclear especially in abiotic stresses. Cadmium (Cd) is a non-essential element that negatively affects plant growth and development. In this study, we provided clear evidence for SR gene involved in Cd tolerance in planta. Systemic expression analysis of 17 Arabidopsis SR genes revealed that SR34b is the only SR gene upregulated by Cd, suggesting its potential roles in Arabidopsis Cd tolerance. Consistent with this, a SR34b T-DNA insertion mutant (sr34b) was moderately sensitive to Cd, which had higher Cd{sup 2+} uptake rate and accumulated Cd in greater amounts than wild-type. This was due to the altered expression of iron-regulated transporter 1 (IRT1) gene in sr34b mutant. Under normal growth conditions, IRT1 mRNAs highly accumulated in sr34b mutant, which was a result of increased stability of IRT1 mRNA. Under Cd stress, however, sr34b mutant plants had a splicing defect in IRT1 gene, thus reducing the IRT1 mRNA accumulation. Despite of this, sr34b mutant plants still constitutively expressed IRT1 proteins under Cd stress, thereby resulting in Cd stress-sensitive phenotype. We therefore propose the essential roles of SR34b in posttranscriptional regulation of IRT1 expression and identify it as a regulator of Arabidopsis Cd tolerance.

  5. Model summary report for the safety assessment SR-Site

    Energy Technology Data Exchange (ETDEWEB)

    Vahlund, Fredrik; Zetterstroem Evins, Lena (Swedish Nuclear Fuel and Waste Management Co., Stockholm (Sweden)); Lindgren, Maria (Kemakta Konsult AB, Stockholm (Sweden))

    2010-12-15

    This document is the model summary report for the safety assessment SR-Site. In the report, the quality assurance (QA) measures conducted for assessment codes are presented together with the chosen QA methodology. In the safety assessment project SR-Site, a large number of numerical models are used to analyse the system and to show compliance. In order to better understand how the different models interact and how information are transferred between the different models Assessment Model Flowcharts, AMFs, are used. From these, different modelling tasks can be identify and the computer codes used. As a large number of computer codes are used in the assessment the complexity of these differs to a large extent, some of the codes are commercial while others are developed especially for the assessment at hand. QA requirements must on the one hand take this diversity into account and on the other hand be well defined. In the methodology section of the report the following requirements are defined for all codes: - It must be demonstrated that the code is suitable for its purpose. - It must be demonstrated that the code has been properly used. - It must be demonstrated that the code development process has followed appropriate procedures and that the code produces accurate results. - It must be described how data are transferred between the different computational tasks. Although the requirements are identical for all codes in the assessment, the measures used to show that the requirements are fulfilled will be different for different types of codes (for instance due to the fact that for some software the source-code is not available for review). Subsequent to the methodology section, each assessment code is presented together with a discussion on how the requirements are met

  6. ASnO/sub 3/ (A=Ca,Sr) perovskites

    Energy Technology Data Exchange (ETDEWEB)

    Vegas, A.; Vallet-Regi, M.; Gonzalez-Calbet, J.M.; Alario-Franco, M.A.

    1986-04-01

    The crystal structures of the perovskites ASnO/sub 3/(A=Ca, Sr) have been solved. CaSnO/sub 3/: Msub(T)=206.77, orthorhombic, Pbnm, a=5.532(2), b=5.681(2), c=7.906(2) A, V=248.46(8) A/sup 3/, Z=4, Dsub(x)=5.52 Mg m/sup -3/, lambda(Mo K..cap alpha..)=0.7107 A, ..mu..(Mo K..cap alpha..)=11.3 mm/sup -1/, F(000)=376, T=295 K. Its structure was refined from 381 (346 observed) X-ray single-crystal data to R=0.026. SrSnO/sub 3/ single crystals, previously reported as cubic (a=8.0682 A), were studied by electron microscopy and X-ray techniques, showing the presence of multitwinning which gives rise to the fictitious ''double'' cubic cell. The real cell has a=5.707(2), b=5.707(2), c=8.064(2) A, V=262.64(8) A/sup 3/, Z=4, Dsub(x)=6.43 Mg m/sup -3/, Msub(T)=254.31, T=295 K, and probably the same space group as CaSnO/sub 3/. Because of the twin, the structure was solved topologically, by a novel use of the expressions given by O'Keeffe and Hyde by assuming an Sn-O bond length of 2.062 A, equal to that derived for CaSnO/sub 3/.

  7. SR and mitochondria: calcium cross-talk between kissing cousins.

    Science.gov (United States)

    Dorn, Gerald W; Maack, Christoph

    2013-02-01

    The processes of excitation-contraction coupling in cardiac myocytes require enormous amounts of energy in the form of ATP, which is produced by oxidative phosphorylation in mitochondria. Due to the constantly varying workloads of the heart, efficient matching of energy supply to demand is a requisite for proper heart function. Ca(2+) is taken up by mitochondria via the mitochondrial Ca(2+) uniporter (MCU) where it stimulates key dehydrogenases of the Krebs cycle to match regeneration of NADH to its oxidation by the respiratory chain. The kinetics of mitochondrial Ca(2+) uptake, however, remain controversial due to the low Ca(2+) sensitivity of the MCU. Here, we review the evidence for the existence of a "mitochondrial Ca(2+) microdomain", in which the close association of the sarcoplasmic reticulum (SR) to mitochondria provides "hot spots" of very high Ca(2+) concentrations in the vicinity of mitochondria, sufficient to overcome the low Ca(2+) affinity of the MCU. Mitofusins 1 and 2 play redundant roles in regulating mitochondrial dynamics by controlling fusion of mitochondria with each other. Recent work revealed a unique role for mitofusin 2 in tethering mitochondria to the sarco-/endoplasmic reticulum in various cell types, including cardiac myocytes. Disruption of SR-mitochondrial Ca(2+) cross talk in heart failure through spatial and ionic alterations may give rise to energetic deficit and oxidative stress, two factors believed to play causal roles in the progression of the disease. On the other hand, excessive mitochondrial Ca(2+) uptake can trigger programmed necrosis, substantiating the ambiguity of the close interplay between these cousin organelles in health and disease. This article is part of a Special Issue entitled "Focus on Cardiac Metabolism". Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Preparation of thermal infrared and microwave absorber using SrTiO{sub 3}/BaFe{sub 12}O{sub 19}/polyaniline nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Hosseini, Seyed Hossein, E-mail: shhosseini@iiau.ac.ir [Department of Chemistry, Faculty of Science, Islamshahr Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Zamani, Parisa [Department of Applied Chemistry, Faculty of Pharmaceutical Chemistry, Pharmaceutical Sciences Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of)

    2016-01-01

    In this research, first, SrTiO{sub 3} was synthesized as thermal infrared (TIR) absorbent and core and then BaFe{sub 12}O{sub 19} as microwave absorbent was prepared on SrTiO{sub 3} via co-precipitation method as first shell. Second, polyaniline (PANI) was coated on SrTiO{sub 3}/BaFe{sub 12}O{sub 19} NPs (NPs) via in situ polymerization by multi core–shell structures (SrTiO{sub 3}/BaFe{sub 12}O{sub 19}/PANI). Nanometer size and structures of samples were measured by TEM, XRD and FTIR. Morphology of nanocomposite was showed by SEM images. The magnetic and electric properties were also performed by VSM and four probe methods. The TIR absorption and microwave reflection loss of nanocomposites were investigated at 10–40 µm and 8–12 GHz, TIR and microwave frequencies, respectively. The results showed that the SrTiO{sub 3}/BaFe{sub 12}O{sub 19}/PANI nanocomposites have good compatible electric and magnetic properties and hence the microwave absorbency show wide bandwidth properties. The infrared thermal image testing showed that the ability of infrared thermal imaging was increased by increasing SrTiO{sub 3}/BaFe{sub 12}O{sub 19} as core and independent to increasing PANI as final shell. - Graphical abstract: The light reflectivity times of samples on human body are higher than metallic disks. So, they are suitable for TIR as absorbers. The light reflectivity times of samples were increased by increasing weight ratio and thickness. Human temperature could not transmit to samples by increasing weight ratio of core. Therefore weight ratio (SrTiO{sub 3}/BaFe{sub 12}O{sub 19} as core) above 40% and 1 mm diameter are the best result as TIR absorber. The SrTiO{sub 3}/BaFe{sub 12}O{sub 19}/PANI enhanced broad band IR light absorption was observed in the wavelength range of 10–40 µm. A minimum RL of −19 dB was observed at 9.2 GHz for a 1.5-mm thickness nanocomposite. The application of these samples may improve the IR thermographic detection, catalysis, sensors

  9. Elemental intermixing within an ultrathin SrRuO3 electrode layer in epitaxial heterostructure BaTiO3/SrRuO3/SrTiO3

    Directory of Open Access Journals (Sweden)

    H. B. Zhang

    2016-01-01

    Full Text Available Aberration corrected scanning transmission electron microscopy is used to directly observe atom columns in an epitaxial BaTiO3 thin film deposited on a 3.6 nm-thick SrRuO3 electrode layer above an SrTiO3 (001 substrate. Compositional gradients across the heterointerfaces were examined using electron energy-loss spectroscopy techniques. It was found that a small amount of Ba and Ti had diffused into the SrRuO3 layer, and that this layer contained a non-negligible concentration of oxygen vacancies. Such point defects are expected to degrade the electrode’s electronic conductivity drastically, resulting in a much longer screening length. This may explain the discrepancy between experimental measurements and theoretical estimates of the ferroelectric critical thickness of a BaTiO3 ferroelectric barrier sandwiched between metallic SrRuO3 electrodes, since theoretical calculations generally assume ideal (stoichiometric perovskite SrRuO3.

  10. Phosphothreonine 218 is required for the function of SR45.1 in regulating flower petal development in Arabidopsis.

    Science.gov (United States)

    Zhang, Xiao-Ning; Mo, Cecilia; Garrett, Wesley M; Cooper, Bret

    2014-01-01

    RNA splicing is crucial to the production of mature mRNAs (mRNA). In Arabidopsis thaliana, the protein Arginine/Serine-rich 45 (SR45) acts as an RNA splicing activator and initiates the spliceosome assembly. SR45 is alternatively spliced into 2 isoforms. Isoform 1 (SR45.1) plays an important role in the flower petal development whereas isoform 2 (SR45.2) is important for root growth. In this study, we used immunoprecipitation to isolate an SR45.1-GFP fusion protein from transgenic plants complementing a null mutant, sr45-1. Mass spectrometry suggested a single phosphorylation event in a peptide from the alternatively spliced region unique to SR45.1. Substituting alanine for threonine 218, a candidate site for phosphorylation, did not complement the sr45-1 mutant with narrow flower petals whereas substituting aspartic acid or glutamic acid for threonine 218 did complement the sr45-1 mutant. Mass spectrometry also revealed that other proteins involved in the spliceosome co-precipitated with SR45.1, and RT-qPCR revealed that phosphorylation of threonine 218 promotes the function of SR45.1 in promoting the constitutive splicing of SR30 mRNA. This is the first demonstration of a specific phosphorylation site that differentially regulates the function of a plant splicing activator in physiologically and morphologically distinct plant tissues.

  11. Spatial distribution of the doped electrons in cubic Sr1 -xLaxMnO3 (x ≤0.04 ) oxides probed by 87Sr NMR

    Science.gov (United States)

    Germov, A.; Trokiner, A.; Volkova, Z.; Mikhalev, K.; Gerashenko, A.; Verkhovskii, S.; Korolev, A.; Leonidov, I.; Konstantinova, E.; Kozhevnikov, V.

    2017-09-01

    The spin density of doped electrons was investigated by 87Sr NMR in the paramagnetic (PM) and antiferromagnetic (AF) G-type phases of electron-doped Sr1 -xLaxMnO3 (x =0.00 , 0.02, 0.04; TN=236 -200 K) ceramics with the cubic structure. It is shown that the 87Sr NMR shift is proportional to the local density of the itinerant doped electrons surrounding the Sr sites; these electrons have mainly the eg character. In the PM phase, all the doped electrons are itinerant; however, they are inhomogeneously distributed in the La-containing oxides, creating electron-doped regions (EDRs) with a number of eg electrons per Mn larger than in the rest of the oxide. At room temperature, the network of the overlapping EDRs does not cover all Sr sites. Nevertheless, the number of the Sr sites inside an EDR exceeds the site percolation threshold even for x =0.02 , so that the eg electrons can move on large distances. In the AF phase, below 80 K the EDRs cover the entire crystal. In this T range the doped electrons separate into two species: some of them slow down their motion and form below 50 K static FM domains, which are considered as bound magnetic polarons (MPs) of small size with the effective moment peff=23 (10 ) μB and a MP formation energy ˜40 meV . The second species concerns the electrons which remain itinerant at low temperature participating in the fast hopping in the AF G-type ordered lattice of the Mn4 + ions. Nevertheless, their motion is slower than what is expected in an AF metal phase without cation disorder; this is probably due to the imperfect shielding of the (La3 +/Sr2 +) charge disorder.

  12. Ion-irradiation induced reduction in Sr2Fe1.5Mo0.5O6-δ perovskite

    Science.gov (United States)

    Wang, Siwei; Tang, Ming; Brinkman, Kyle S.; Chen, Fanglin (Frank)

    2014-05-01

    The incorporation of radioactive elements in fission products (FPs) into complex oxides, where the elements are constrained in the structure and enhanced leaching and radioactive stability can be obtained, is an active research area in the nuclear fuel cycle. Perovskite structured Sr2Fe1.5Mo0.5O6-δ (SFM) has the capability of incorporating several FPs (such as Sr and Mo) into the crystalline network simultaneously while maintaining a stabilized structure. The radiation damage effects on the structure changes of this polycrystalline SFM sample is conducted under various ion irradiations including 200 keV He ions to a fluence of 5 × 1020 ions m-2, 100 keV H to a fluence of 3 × 1021 ions cm-2, and 600 keV Kr ions to a fluence of 2.5 × 1019 ions m-2 at room temperature. Irradiation-induced structural evolution was examined by using grazing incidence X-ray diffraction and cross-sectional transmission electron microscopy. It was found that the irradiated SFM sample decomposed into a layered Sr4FeMoO8-δ based phase and a metallic Fe based phase under light ion (He and H) irradiations. Nano-crystallized secondary phase was observed with particle sizes around 7 nm. These results suggest that irradiation-induced reducing atmospheres may affect the stability of crystalline structure in complex oxides. Experiment results also reveal an amorphization in the heavy ion Kr irradiated sample, while no amorphization is observed in He/H irradiated SFM.

  13. Modelling the Phanerozoic carbon cycle and climate: constraints from the 87Sr/86Sr isotopic ratio of seawater

    Science.gov (United States)

    Francois, L. M.; Walker, J. C.

    1992-01-01

    A numerical model describing the coupled evolution of the biogeochemical cycles of carbon, sulfur, calcium, magnesium, phosphorus, and strontium has been developed to describe the long-term changes of atmospheric carbon dioxide and climate during the Phanerozoic. The emphasis is on the effects of coupling the cycles of carbon and strontium. Various interpretations of the observed Phanerozoic history of the seawater 87Sr/86Sr ratio are investigated with the model. More specifically, the abilities of continental weathering, volcanism, and surface lithology in generating that signal are tested and compared. It is suggested that the observed fluctuations are mostly due to a changing weatherability over time. It is shown that such a conclusion is very important for the modelling of the carbon cycle. Indeed, it implies that the conventional belief that the evolution of atmospheric carbon dioxide and climate on a long time scale is governed by the balance between the volcanic input of CO2 and the rate of silicate weathering is not true. Rather carbon exchanges between the mantle and the exogenic system are likely to have played a key role too. Further, the increase of the global weathering rates with increasing surface temperature and/or atmospheric CO2 pressure usually postulated in long-term carbon cycle and climate modelling is also inconsistent with the new model. Other factors appear to have modulated the weatherability of the continents through time, such as mountain building and the existence of glaciers and ice sheets. Based on these observations, a history of atmospheric carbon dioxide and climate during Phanerozoic time, consistent with the strontium isotopic data, is reconstructed with the model and is shown to be compatible with paleoclimatic indicators, such as the timing of glaciation and the estimates of Cretaceous paleotemperatures.

  14. Investigating human geographic origins using dual-isotope (87Sr/86Sr, δ18O) assignment approaches.

    Science.gov (United States)

    Laffoon, Jason E; Sonnemann, Till F; Shafie, Termeh; Hofman, Corinne L; Brandes, Ulrik; Davies, Gareth R

    2017-01-01

    Substantial progress in the application of multiple isotope analyses has greatly improved the ability to identify nonlocal individuals amongst archaeological populations over the past decades. More recently the development of large scale models of spatial isotopic variation (isoscapes) has contributed to improved geographic assignments of human and animal origins. Persistent challenges remain, however, in the accurate identification of individual geographic origins from skeletal isotope data in studies of human (and animal) migration and provenance. In an attempt to develop and test more standardized and quantitative approaches to geographic assignment of individual origins using isotopic data two methods, combining 87Sr/86Sr and δ18O isoscapes, are examined for the Circum-Caribbean region: 1) an Interval approach using a defined range of fixed isotopic variation per location; and 2) a Likelihood assignment approach using univariate and bivariate probability density functions. These two methods are tested with enamel isotope data from a modern sample of known origin from Caracas, Venezuela and further explored with two archaeological samples of unknown origin recovered from Cuba and Trinidad. The results emphasize both the potential and limitation of the different approaches. Validation tests on the known origin sample exclude most areas of the Circum-Caribbean region and correctly highlight Caracas as a possible place of origin with both approaches. The positive validation results clearly demonstrate the overall efficacy of a dual-isotope approach to geoprovenance. The accuracy and precision of geographic assignments may be further improved by better understanding of the relationships between environmental and biological isotope variation; continued development and refinement of relevant isoscapes; and the eventual incorporation of a broader array of isotope proxy data.

  15. Sub-10 nm Sr2LuF7:Yb/Er@Sr2GdF7@SrF2 Up-Conversion Nanocrystals for Up-Conversion Luminescence-Magnetic Resonance-Computed Tomography Trimodal Bioimaging.

    Science.gov (United States)

    Chen, Cailing; Liu, Jianhua; Chen, Ying; Li, Chunguang; Liu, Xiaomin; Huang, He; Liang, Chen; Lou, Yue; Shi, Zhan; Feng, Shouhua

    2017-02-22

    Herein, sub-10 nm core-shell nanocrystals (NCs), which select Sr2LuF7:Yb/Er as core, Sr2GdF7 as middle shell, and SrF2 as an outermost shell, were synthesized by a seed-mediated growth process. The NCs possess good crystallinity, morphology, and up-conversion luminescent properties. After modification by polyethylenimine branched (PEI), in vitro cell up-conversion imaging with low autofluorescence was realized. Due to the presence of Gd(3+) ions, in vivo magnetic resonance (MR) imaging was also achieved with these designed NCs. More significantly, these special core-shell NCs exhibited high contrast in in vivo X-ray computed tomography (CT) imaging because of their good X-ray absorption ability. These results indicate that the core-shell up-conversion NCs can serve as promising contrast agents for up-conversion luminescence-MR-CT trimodal bioimaging.

  16. First report of 'Candidatus Phytoplasma trifolii'-related strain of 16SrVI-A phytoplasma subgroup, associated with elm yellows disease in American elm (Ulmus americana L.) in Ohio, USA

    Science.gov (United States)

    Charles Elliot Flower; Nancy L Hayes-Plazolles; Cristina Rosa; James M Slavicek

    2017-01-01

    During the investigation of the sudden and early onset of yellowing and mortality of American elm (Ulmus americana L.) trees at the USDA Forest Service Northern Research Station in Delaware, OH, a phytoplasma of the clover proliferation group (16SrVI) was detected as the putative causal agent of the disease outbreak.

  17. Researcher / Researched: Repositioning Research Paradigms

    Science.gov (United States)

    Meerwald, Agnes May Lin

    2013-01-01

    "Researcher / Researched" calls for a complementary research methodology by proposing autoethnography as both a method and text that crosses the boundaries of conventional and alternative methodologies in higher education. Autoethnography rearticulates the researcher / researched positions by blurring the boundary between them. This…

  18. High-frequency effects in antiferromagnetic Sr3Ir2O7

    Science.gov (United States)

    Williamson, Morgan; Seinige, Heidi; Shen, Shida; Wang, Cheng; Cao, Gang; Zhou, Jianshi; Goodenough, John; Tsoi, Maxim

    Antiferromagnetic (AFM) spintronics is one of many promising routes for `beyond the CMOS' technologies where unique properties of AFM materials are exploited to achieve new and improved functionalities. AFMs are especially interesting for high-speed memory applications thanks to their high natural frequencies. Here we report the effects of high-frequency (microwave) currents on transport properties of antiferromagnetic Mott insulator Sr3Ir2O7. The microwaves at 3-7 GHz were found to affect the material's current-voltage characteristic and produce resonance-like features that we tentatively associate with the dissipationless magnonics recently predicted to occur in antiferromagnetic insulators subject to ac electric fields. Our observations support the potential of antiferromagnetic materials for high-speed/high-frequency spintronic applications. This work was supported in part by C-SPIN, one of six centers of STARnet, a Semiconductor Research Corporation program, sponsored by MARCO and DARPA, by NSF Grants DMR-1207577, DMR-1265162, DMR-1600057, and DMR-1122603, and by the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under Award No. OSR-2015-CRG4-2626.

  19. Disruption of Two-component System LytSR Affects Forespore Engulfment in Bacillus thuringiensis

    Directory of Open Access Journals (Sweden)

    Qi Peng

    2017-11-01

    Full Text Available Two-component regulatory systems (TCSs play pivotal roles in bacteria sensing many different stimuli from environment. Here, we investigated the role of the LytSR TCS in spore formation in Bacillus thuringiensis (Bt subsp. kurstaki HD73. lacZ gene fusions revealed that the transcription of the downstream genes, lrgAB, encoding two putative membrane-associated proteins, is regulated by LytSR. The sporulation efficiency of a lytSR mutant was significantly lower than that of wild-type HD73. A confocal microscopic analysis demonstrated that LytSR modulates the process of forespore engulfment. Moreover, the transcription of the lytSR operon is regulated by the mother-cell transcription factor SigE, whereas the transcription of the sporulation gene spoIIP was reduced in the lytSR mutant, as demonstrated with a β-galactosidase activity assay. These results suggest that LytSR modulates forespore engulfment by affecting the transcription of the spoIIP gene in Bt.

  20. Disruption of Two-component System LytSR Affects Forespore Engulfment in Bacillus thuringiensis.

    Science.gov (United States)

    Peng, Qi; Wu, Jianbo; Chen, Xiaomin; Qiu, Lili; Zhang, Jie; Tian, Hongtao; Song, Fuping

    2017-01-01

    Two-component regulatory systems (TCSs) play pivotal roles in bacteria sensing many different stimuli from environment. Here, we investigated the role of the LytSR TCS in spore formation in Bacillus thuringiensis (Bt) subsp. kurstaki HD73. lacZ gene fusions revealed that the transcription of the downstream genes, lrgAB, encoding two putative membrane-associated proteins, is regulated by LytSR. The sporulation efficiency of a lytSR mutant was significantly lower than that of wild-type HD73. A confocal microscopic analysis demonstrated that LytSR modulates the process of forespore engulfment. Moreover, the transcription of the lytSR operon is regulated by the mother-cell transcription factor SigE, whereas the transcription of the sporulation gene spoIIP was reduced in the lytSR mutant, as demonstrated with a β-galactosidase activity assay. These results suggest that LytSR modulates forespore engulfment by affecting the transcription of the spoIIP gene in Bt.

  1. Using medical accelerators and photon activation to determine Sr/Ca concentration ratios in teeth

    Energy Technology Data Exchange (ETDEWEB)

    Chao, J.H. [Nuclear Science and Technology Development Center, National Tsing Hua University, Hsinchu 300, Taiwan (China)], E-mail: jhchao@mx.nthu.edu.tw; Liu, M.T. [Department of Radiation Oncology, Changhua Christian Hospital, Changhua 500, Taiwan (China); Yeh, S.A. [Department of Radiation Oncology, E-Da Hospital, Kaohsiung 824, Taiwan (China); Department of Medical Imaging and Radiological Sciences, I-Shou University, Kaohsiung 824, Taiwan (China); Huang, S.S. [Department of Radiation Oncology, Changhua Christian Hospital, Changhua 500, Taiwan (China); Wu, J.M. [Department of Radiation Oncology, E-Da Hospital, Kaohsiung 824, Taiwan (China); Department of Medical Imaging and Radiological Sciences, I-Shou University, Kaohsiung 824, Taiwan (China); Chang, Y.L. [Nuclear Science and Technology Development Center, National Tsing Hua University, Hsinchu 300, Taiwan (China); Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 300, Taiwan (China); Hsu, F.Y. [Nuclear Science and Technology Development Center, National Tsing Hua University, Hsinchu 300, Taiwan (China); Chuang, C.Y.; Liu, H.Y.; Sun, Y.C. [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu 300, Taiwan (China)

    2009-06-15

    This paper describes a photon activation method, studied by using two medical accelerators (energies: 15 and 18 MeV) as photon sources, for determining Sr and Ca levels and Sr/Ca ratios in tooth samples. The radionuclides formed by various photonuclear reactions were measured and identified using a gamma-spectrometry with HPGe detection system. The yields of the corresponding photonuclear reactions and the detection sensitivities for the alkaline earth metals (e.g., Ca, Sr) were surveyed and estimated in relation to the radiation dose. The minimum detectable amount of Sr was estimated to be less than 1 {mu}g g{sup -1}, allowing the Sr/Ca ratios in teeth to be determined conveniently. The Sr/Ca ratios in deciduous and permanent tooth samples obtained from local dental clinics were 0.390 and 0.565 mg g{sup -1}, respectively. This photon activation method of determining Sr/Ca ratio in bones and teeth using medical accelerators for cancer treatment is thought to be useful also in biological and archaeological studies.

  2. Structure-property relations in Sr, Nb, Ba doped lead zirconate titanate

    CERN Document Server

    Zheng, H

    2001-01-01

    rhombohedral or tetragonal forms or as mixture of the two (MPB), depending on Zi:Ti ratio. Zr:Ti ratio strongly affected d sub 3 sub 3 , which was maximised in the tetragonal phase close to, but not at, the MPB. Sr sup 2 sup + substitution on the A-site promoted tetragonality in PZT, greatly reducing T sub C , and broadening the dielectric maximum. As the Sr sup 2 sup + content was increased, Zr:Ti ratio was adjusted to maximise d sub 3 sub 3 and the optimised d sub 3 sub 3 values increased from 410 pC/N (Sr sup 2 sup + = 0) to 640 pC/N (Sr sup 2 sup + = 0.12), commensurate with a decrease in the T sub C. However, for ceramics where Sr sup 2 sup + > 0.12, optimised d sub 3 sub 3 decreased with respect to the values for ceramics where Sr sup 2 sup + = 0.12 even though T sub C was lowered. Electron diffraction patterns revealed superlattice reflections occurring at 1/2 left brace hkl right brace positions associated with rotations of oxygen octahedra in anti-phase. It was suggested that Sr sup 2 sup + substitut...

  3. Bi-modal regulation of a formin by srGAP2.

    Science.gov (United States)

    Mason, Frank M; Heimsath, Ernest G; Higgs, Henry N; Soderling, Scott H

    2011-02-25

    The maintenance of rapid and efficient actin dynamics in vivo requires coordination of filament assembly and disassembly. This regulation requires temporal and spatial integration of signaling pathways by protein complexes. However, it remains unclear how these complexes form and then regulate the actin cytoskeleton. Here, we identify a srGAP2 and formin-like 1 (FMNL1, also known as FRL1 or FRLα) complex whose assembly is regulated by Rac signaling. Our data suggest srGAP2 regulates FMNL1 in two ways; 1) Rac-mediated activation of FMNL1 leads to the recruitment of srGAP2, which contains a Rac-specific GAP domain; 2) the SH3 domain of srGAP2 binds the formin homology 1 domain of FMNL1 to inhibit FMNL1-mediated actin severing. Thus, srGAP2 can efficiently terminate the upstream activating Rac signal while also opposing an important functional output of FMNL1, namely actin severing. We also show that FMNL1 and srGAP2 localize to the actin-rich phagocytic cup of macrophage-derived cells, suggesting the complex may regulate this Rac- and actin-driven process in vivo. We propose that after Rac-dependent activation of FMNL1, srGAP2 mediates a potent mechanism to limit the duration of Rac action and inhibit formin activity during rapid actin dynamics.

  4. SR-B1 Is a Silica Receptor that Mediates Canonical Inflammasome Activation

    Directory of Open Access Journals (Sweden)

    Misato Tsugita

    2017-01-01

    Full Text Available The inhalation of silica dust is associated with fibrosis and lung cancer, which are triggered by macrophage inflammatory responses; however, how macrophages recognize silica remains largely unknown. Here, we identify by functional expression cloning the class B scavenger receptor SR-B1 as a silica receptor. Through an extracellular α-helix, both mouse and human SR-B1 specifically recognized amorphous and crystalline silica, but not titanium dioxide nanoparticles, latex nanoparticles, or monosodium urate crystals, although all particles exhibited negative surface potentials. Genetic deletion of SR-B1 and masking of SR-B1 by monoclonal antibodies showed that SR-B1-mediated recognition of silica is associated with caspase-1-mediated inflammatory responses in mouse macrophages and human peripheral blood monocytes. Furthermore, SR-B1 was involved in silica-induced pulmonary inflammation in mice. These results indicate that SR-B1 is a silica receptor associated with canonical inflammasome activation.

  5. Targeting the SR-B1 Receptor as a Gateway for Cancer Therapy and Imaging.

    Science.gov (United States)

    Mooberry, Linda K; Sabnis, Nirupama A; Panchoo, Marlyn; Nagarajan, Bhavani; Lacko, Andras G

    2016-01-01

    Malignant tumors display remarkable heterogeneity to the extent that even at the same tissue site different types of cells with varying genetic background may be found. In contrast, a relatively consistent marker the scavenger receptor type B1 (SR-B1) has been found to be consistently overexpressed by most tumor cells. Scavenger Receptor Class B Type I (SR-BI) is a high density lipoprotein (HDL) receptor that facilitates the uptake of cholesterol esters from circulating lipoproteins. Additional findings suggest a critical role for SR-BI in cholesterol metabolism, signaling, motility, and proliferation of cancer cells and thus a potential major impact in carcinogenesis and metastasis. Recent findings indicate that the level of SR-BI expression correlate with aggressiveness and poor survival in breast and prostate cancer. Moreover, genomic data show that depending on the type of cancer, high or low SR-BI expression may promote poor survival. This review discusses the importance of SR-BI as a diagnostic as well as prognostic indicator of cancer to help elucidate the contributions of this protein to cancer development, progression, and survival. In addition, the SR-B1 receptor has been shown to serve as a potential gateway for the delivery of therapeutic agents when reconstituted high density lipoprotein nanoparticles are used for their transport to cancer cells and tumors. Opportunities for the development of new technologies, particularly in the areas of cancer therapy and tumor imaging are discussed.

  6. Determination of Sr-90 in milk samples from the study of statistical results

    Directory of Open Access Journals (Sweden)

    Otero-Pazos Alberto

    2017-01-01

    Full Text Available The determination of 90Sr in milk samples is the main objective of radiation monitoring laboratories because of its environmental importance. In this paper the concentration of activity of 39 milk samples was obtained through radiochemical separation based on selective retention of Sr in a cationic resin (Dowex 50WX8, 50-100 mesh and subsequent determination by a low-level proportional gas counter. The results were checked by performing the measurement of the Sr concentration by using the flame atomic absorption spectroscopy technique, to finally obtain the mass of 90Sr. From the data obtained a statistical treatment was performed using linear regressions. A reliable estimate of the mass of 90Sr was obtained based on the gravimetric technique, and secondly, the counts per minute of the third measurement in the 90Sr and 90Y equilibrium, without having to perform the analysis. These estimates have been verified with 19 milk samples, obtaining overlapping results. The novelty of the manuscript is the possibility of determining the concentration of 90Sr in milk samples, without the need to perform the third measurement in the equilibrium.

  7. SR-B1 Is a Silica Receptor that Mediates Canonical Inflammasome Activation.

    Science.gov (United States)

    Tsugita, Misato; Morimoto, Nobuyuki; Tashiro, Manabu; Kinoshita, Kengo; Nakayama, Masafumi

    2017-01-31

    The inhalation of silica dust is associated with fibrosis and lung cancer, which are triggered by macrophage inflammatory responses; however, how macrophages recognize silica remains largely unknown. Here, we identify by functional expression cloning the class B scavenger receptor SR-B1 as a silica receptor. Through an extracellular α-helix, both mouse and human SR-B1 specifically recognized amorphous and crystalline silica, but not titanium dioxide nanoparticles, latex nanoparticles, or monosodium urate crystals, although all particles exhibited negative surface potentials. Genetic deletion of SR-B1 and masking of SR-B1 by monoclonal antibodies showed that SR-B1-mediated recognition of silica is associated with caspase-1-mediated inflammatory responses in mouse macrophages and human peripheral blood monocytes. Furthermore, SR-B1 was involved in silica-induced pulmonary inflammation in mice. These results indicate that SR-B1 is a silica receptor associated with canonical inflammasome activation. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  8. UGA is an additional glycine codon in uncultured SR1 bacteria from the human microbiota

    Science.gov (United States)

    Campbell, James H.; O’Donoghue, Patrick; Campbell, Alisha G.; Schwientek, Patrick; Sczyrba, Alexander; Woyke, Tanja; Söll, Dieter; Podar, Mircea

    2013-01-01

    The composition of the human microbiota is recognized as an important factor in human health and disease. Many of our cohabitating microbes belong to phylum-level divisions for which there are no cultivated representatives and are only represented by small subunit rRNA sequences. For one such taxon (SR1), which includes bacteria with elevated abundance in periodontitis, we provide a single-cell genome sequence from a healthy oral sample. SR1 bacteria use a unique genetic code. In-frame TGA (opal) codons are found in most genes (85%), often at loci normally encoding conserved glycine residues. UGA appears not to function as a stop codon and is in equilibrium with the canonical GGN glycine codons, displaying strain-specific variation across the human population. SR1 encodes a divergent tRNAGlyUCA with an opal-decoding anticodon. SR1 glycyl-tRNA synthetase acylates tRNAGlyUCA with glycine in vitro with similar activity compared with normal tRNAGlyUCC. Coexpression of SR1 glycyl-tRNA synthetase and tRNAGlyUCA in Escherichia coli yields significant β-galactosidase activity in vivo from a lacZ gene containing an in-frame TGA codon. Comparative genomic analysis with Human Microbiome Project data revealed that the human body harbors a striking diversity of SR1 bacteria. This is a surprising finding because SR1 is most closely related to bacteria that live in anoxic and thermal environments. Some of these bacteria share common genetic and metabolic features with SR1, including UGA to glycine reassignment and an archaeal-type ribulose-1,5-bisphosphate carboxylase (RubisCO) involved in AMP recycling. UGA codon reassignment renders SR1 genes untranslatable by other bacteria, which impacts horizontal gene transfer within the human microbiota. PMID:23509275

  9. Exploring the Middle Pleistocene Lake Suguta Sr-isotope Stratigraphic record

    Science.gov (United States)

    Vonhof, Hubert; Junginger, Annett; Agmon, Nadav; Trauth, Martin

    2017-04-01

    Several studies into the Quaternary stratigraphic record of the Sr-isotope composition of paleolake Turkana in the East African Rift System (EARS) show how variation of climate left a signal of changing lacustrine Sr isotope values. This Sr isotope signal was captured in the lacustrine fossil record of the Turkana Basin, and can be a useful chemostratigraphic tool (e.g. Joordens et al., 2011; van der Lubbe et al., submitted). Such lacustrine Sr-isotope changes are believed to be paced by orbital-forced insolation cyclicity, and interpreted to be the result of changing contribution of run-off from different sub-catchments of lake Turkana, as climate change shifted regional rainfall patterns. Here, we present a first set of data from a middle Pleistocene stratigraphical sequence in the Suguta Valley, South of the Turkana Basin in the EARS. This sequence spans a couple of sedimentological cycles that potentially represent precession-forced lake level variation. In this setting, the Sr-isotope data do not vary in phase with these sedimentological cycles, but demonstrate a long trend of Sr isotope change. This may suggest that the catchment configuration of the Suguta Valley in the Mid Pleistocene was less suitable to record precession-forced hydroclimate change in Lacustrine Sr isotope ratios. This may have implications for the Turkana Basin Sr isotope record as well, because the two basins are believed to have been hydrologically connected in the Middle Pleistocene. references: 1)Joordens, J.C.A. et al., 2011. An astronomically-tuned climate framework for hominins in the Turkana Basin. Earth and Planetary Science Letters 307, 1-8. 2)van der Lubbe et al., submitted. Gradual or abrupt? Changes in water source of Lake Turkana (Kenya) during the African Humid Period inferred from Sr isotope ratios

  10. UGA is an additional glycine codon in uncultured SR1 bacteria from the human microbiota.

    Science.gov (United States)

    Campbell, James H; O'Donoghue, Patrick; Campbell, Alisha G; Schwientek, Patrick; Sczyrba, Alexander; Woyke, Tanja; Söll, Dieter; Podar, Mircea

    2013-04-02

    The composition of the human microbiota is recognized as an important factor in human health and disease. Many of our cohabitating microbes belong to phylum-level divisions for which there are no cultivated representatives and are only represented by small subunit rRNA sequences. For one such taxon (SR1), which includes bacteria with elevated abundance in periodontitis, we provide a single-cell genome sequence from a healthy oral sample. SR1 bacteria use a unique genetic code. In-frame TGA (opal) codons are found in most genes (85%), often at loci normally encoding conserved glycine residues. UGA appears not to function as a stop codon and is in equilibrium with the canonical GGN glycine codons, displaying strain-specific variation across the human population. SR1 encodes a divergent tRNA(Gly)UCA with an opal-decoding anticodon. SR1 glycyl-tRNA synthetase acylates tRNA(Gly)UCA with glycine in vitro with similar activity compared with normal tRNA(Gly)UCC. Coexpression of SR1 glycyl-tRNA synthetase and tRNA(Gly)UCA in Escherichia coli yields significant β-galactosidase activity in vivo from a lacZ gene containing an in-frame TGA codon. Comparative genomic analysis with Human Microbiome Project data revealed that the human body harbors a striking diversity of SR1 bacteria. This is a surprising finding because SR1 is most closely related to bacteria that live in anoxic and thermal environments. Some of these bacteria share common genetic and metabolic features with SR1, including UGA to glycine reassignment and an archaeal-type ribulose-1,5-bisphosphate carboxylase (RubisCO) involved in AMP recycling. UGA codon reassignment renders SR1 genes untranslatable by other bacteria, which impacts horizontal gene transfer within the human microbiota.

  11. Planning report for the safety assessment SR-Can

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-06-01

    This document is a planning report for SKB's next assessment of long-term safety for a KBS 3 repository. The assessment, SR-Can, is to be finished by the end of 2005 and will be used for SKB's application to build an Encapsulation plant for spent nuclear fuel. Apart from outlining the methodology, the report discusses the handling in SR-Can of a number of important issues regarding the near field, the geosphere, the biosphere, the climatic evolution etc. The Swedish nuclear safety and radiation protection authorities have recently issued regulations concerning the final disposal of nuclear waste. The principal compliance criterion states that the annual risk of harmful effects must not exceed 10{sup -6} for a representative individual in the group exposed to the greatest risk. There are also a number of requirements on methodological aspects of the safety assessment as well as on the contents of a safety report. The regulations are reproduced in an Appendix to this report. The primary safety function of the KBS 3 system is to completely isolate the spent nuclear fuel within copper canisters over the entire assessment period, which will be one million years in SR-Can. Should a canister be damaged, the secondary safety function is to retard any releases from the canisters. The main steps of the assessment are the following: 1. Qualitative system description, FEP processing: This step consists of defining a system boundary and of describing the system on a format suitable for the safety assessment. Databases of relevant features, events and processes influencing long-term safety are structured and used as one starting point for the assessment. 2. Initial state descriptions. 3. Process descriptions: In this step all identified processes within the system boundary involved in the long-term evolution of the system are described in detail. 4. Description of boundary conditions: This step is a broad description of the evolution of the boundaries of the system

  12. Origin of the stabilization of the metastable tetragonal high-pressure phase in SrCuO2 thin films grown on SrTiO3 substrates by pulsed laser deposition

    Science.gov (United States)

    Mihailescu, C. N.; Pasuk, I.; Straticiuc, M.; Nita, C. R.; Pantelica, D.; Giapintzakis, J.

    2014-11-01

    In this work we have systematically investigated the evolution of structure and stoichiometry in SrCuO2 films grown on TiO2-terminated SrTiO3 substrates as a function of the substrate temperature. Depending on the growth temperature SrCuO2/SrTiO3 films can exhibit either a pure tetragonal high-pressure phase, or a pure orthorhombic low-pressure phase, or a mixed phase. Our results indicate that at low substrate temperatures the non-equilibrium state of the growth process is responsible for the stabilization of the metastable tetragonal high-pressure structure in SrCuO2 thin films grown on (0 0 1) SrTiO3 substrates, whose lattice matches the metastable structure. In addition, at higher substrate temperatures thermodynamics become dominant over other factors and the SrCuO2 thin films are stabilized in the thermodynamically stable orthorhombic phase.

  13. Domain structure and magnetic properties of epitaxial SrRuO sub 3 films grown on SrTiO sub 3 (100) substrates by ion beam sputtering

    CERN Document Server

    Oh, S H

    2000-01-01

    The domain structure of epitaxial SrRuO sub 3 thin films grown on SrTiO sub 3 (100) substrates by using ion beam sputtering has been investigated with transmission electron microscopy (TEM) and X-ray diffraction (XRD). The SrRuO sub 3 films grown in the present study revealed a unique cube-on-cube epitaxial relationship, i.e., (100) sub S sub R sub O ll (100) sub S sub T sub O , [010] sub S sub R sub O ll [101] sub S sub T sub O , prevailing with a cubic single-domain structure. The cubic SrRuO sub 3 thin films that were inherently with free from RuO sub 6 octahedron tilting exhibited higher resistivity with suppressed magnetic properties. The Curie temperature of the thin films was suppressed by 60 K from 160 K for the bulk specimen, and the saturation magnetic moment was reduced by a significant amount. The tetragonal distortion of the SrRuO sub 3 thin films due to coherent growth with the substrate seemed to result in a strong magnetic anisotropy.

  14. Transport anisotropy of LaAlO{sub 3}/SrTiO{sub 3} interfaces on chemically patterned SrTiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Foerster, Michael; Bachelet, Romain; Fontcuberta, Josep; Herranz, Gervasi; Sanchez, Florencio [Institut de Ciencia de Materials de Barcelona ICMAB-CSIC, Campus de la UAB, 08193 Bellaterra, Catalonia (Spain); Laukhin, Vladimir [Institut de Ciencia de Materials de Barcelona ICMAB-CSIC, Campus de la UAB, 08193 Bellaterra, Catalonia (Spain); Institucio Catalana de Recerca i Estudis Avancats (ICREA), 08010 Barcelona, Catalonia (Spain)

    2012-07-01

    A few years ago high mobility electronic transport was found at the interface between the wide bandgap insulators SrTiO{sub 3} and LaAlO{sub 3}. This conductive layer is confined to a few unit cells around the interface and it appears when LaAlO{sub 3} layers with thickness above 3-4 unit cells are grown on SrTiO{sub 3}. It is known that TiO{sub 2}/LaO interfaces are conductive, while SrO/AlO{sub 2} interfaces are insulating. Here we exploited this way to control the interface properties to produce large scale functional nanostructures. TiO{sub 2}/AlO-SrO/LaO{sub 2} modulated interfaces have been prepared using thermally treated SrTiO{sub 3} surfaces with self-organized patterned chemical termination. The interface transport properties are found to be controlled according to these interface patterns. While the influence of the interface topology, e.g. terrace steps, is negligible, a strong transport anisotropy is observed when large-scale well oriented chemical patterns are realized. Our results show that bottom-up engineering of the interface chemical composition is a suitable strategy to influence the transport properties on large scales.

  15. Adsorption of water on (0 0 1) surface of SrTiO 3 and SrZrO 3 cubic perovskites: Hybrid HF-DFT LCAO calculations

    Science.gov (United States)

    Evarestov, R. A.; Bandura, A. V.; Alexandrov, V. E.

    2007-04-01

    Hybrid HF-DFT LCAO simulations of (0 0 1) surface properties and water adsorption on cubic SrZrO 3 and SrTiO 3 perovskites are performed using a single slab model framework. Three slab models with the different surface termination including 6-11 atomic planes were used for calculations. The effect of the symmetry reduction and the role of an extra atomic layer basis set have been considered for the bare surface slabs. The optimized structures and water adsorption energies have been calculated for the various types of surface coverage. It is shown that the formation of H-bonds between the water hydrogens and surface oxygens, as well as between the water molecules themselves, controls the structure of the water adsorption layers on the perovskite surfaces. Obtained results indicate that the dissociative type of water adsorption is the energetically more favourable for SrO-terminated zirconate surface than for similar titanate surface giving evidence to the more basic nature of oxygen atoms on SrO-terminated SrZrO 3 surface.

  16. Study of shape evolution and electromagnetic properties in neutron-rich Zr and Sr isotopes

    Science.gov (United States)

    Chaudhary, R.; Devi, R.; Khosa, S. K.

    2017-09-01

    The projected shell model calculations have been carried out in neutron-rich 100-108Zr and 98-102Sr isotopes. The shape evolution and electromagnetic properties have been examined in neutron-rich Zr and Sr isotopes around N = 60. The structure of yrast states, backbending phenomena, g-factors and B(E2) transition probabilities are calculated and compared with corresponding observable quantities. The present calculations predict the occurrence of coexistence of prolate-oblate shapes at 0+ state in 100,102Zr and 98,100Sr. Nuclei beyond N = 62 are predicted to have prolate deformation in the ground-state.

  17. Large scale production of SrFe12O19 nanoparticles with low calcination temperature

    Science.gov (United States)

    Kumar, M. Rajesh; Yu, Z. J.; Pan, Q.

    2017-09-01

    High quality SrFe12O19 nanoparticles were successfully synthesized by a co-precipitation method with low calcination temperature. Structural, morphological and magnetic properties of SrFe12O19 nanoparticles were investigated by means of x-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM) analysis. The formation of SrFe12O19 nanoparticles were confirmed by XRD analysis. The actual size and morphology of the nanoparticles were characterized by SEM.

  18. TCP-Friendly Retransmission Persistence Management for SR-ARQ Protocols

    Science.gov (United States)

    Han, Jechan; Kim, Beomjoon; Lee, Jaiyong

    This letter proposes a new retransmission persistence management scheme for selective repeat automatic repeat request (SR-ARQ). By considering the overall traffic load that has to be managed by SR-ARQ, the proposed scheme arbitrates the retransmission persistence to prevent an abrupt delay increment due to excessive link-level local retransmissions. OPNET simulations show that SR-ARQ performs better with the proposed scheme than with a fixed value of retransmission persistence in terms of the throughput of transmission control protocol (TCP).

  19. Experimental Study of the Al-Mg-Sr Phase Diagram at 400°C

    Directory of Open Access Journals (Sweden)

    D. Kevorkov

    2014-01-01

    Full Text Available The Al-Mg-Sr system is experimentally studied at 400°C using EPMA and XRD techniques. It was determined that the intermetallic phases in the Al-Mg-Sr system have a tendency to form extended substitutional solid solutions. Two ternary phases were found in this system. Solubility limits of binary and ternary phases were determined and the phase equilibria among phases were established. The isothermal section of the Al-Mg-Sr system at 400°C has been constructed using results of the phase analysis and experimental literature data.

  20. Epithelial CaSR Deficiency Alters Intestinal Integrity and Promotes Proinflammatory Immune Responses

    Science.gov (United States)

    Cheng, Sam X.; Lightfoot, Yaíma L.; Yang, Tao; Zadeh, Mojgan; Tang, Lieqi; Sahay, Bikash; Wang, Gary P.; Owen, Jennifer L.; Mohamadzadeh, Mansour

    2014-01-01

    The intestinal epithelium is equipped with sensing receptor mechanisms that interact with luminal microorganisms and nutrients to regulate barrier function and gut immune responses, thereby maintaining intestinal homeostasis. Herein, we clarify the role of the extracellular calcium-sensing receptor (CaSR) using intestinal epithelium-specific Casr−/− mice. Epithelial CaSR deficiency diminished intestinal barrier function, altered microbiota composition, and skewed immune responses towards proinflammatory. Consequently, Casr−/− mice were significantly more prone to chemically induced intestinal inflammation resulting in colitis. Accordingly, CaSR represents a potential therapeutic target for autoinflammatory disorders, including inflammatory bowel diseases. PMID:24842610

  1. Probing electronic state at atomic scale on the surface of SrVO3 film

    Science.gov (United States)

    Okada, Yoshinori; Shimizu, Ryota; Shiraki, Susumu; Hitosugi, Taro

    2014-03-01

    Probing electronic structure of atomically well controlled surface of Perovskite-type 3d transition-metal oxides have been attracting much interest because of their intriguing emergent physical properties by heterostructure engineering. In this study, we have especially focused on SrVO3, where importance of correlation effects has been considered. We successfully obtained atomically flat surfaces of SrVO3, which gave us the great opportunity to visualize correlated electronic state at atomic scale by means of spectroscopic imaging scanning tunneling spectroscopy. Based on the experimental data, we discuss spectroscopic signature of many body effects on the surface of SrVO3 system.

  2. Use of the Environment and Policy Evaluation and Observation as a Self-Report Instrument (EPAO-SR) to measure nutrition and physical activity environments in child care settings: validity and reliability evidence.

    Science.gov (United States)

    Ward, Dianne S; Mazzucca, Stephanie; McWilliams, Christina; Hales, Derek

    2015-09-26

    Early care and education (ECE) centers are important settings influencing young children's diet and physical activity (PA) behaviors. To better understand their impact on diet and PA behaviors as well as to evaluate public health programs aimed at ECE settings, we developed and tested the Environment and Policy Assessment and Observation - Self-Report (EPAO-SR), a self-administered version of the previously validated, researcher-administered EPAO. Development of the EPAO-SR instrument included modification of items from the EPAO, community advisory group and expert review, and cognitive interviews with center directors and classroom teachers. Reliability and validity data were collected across 4 days in 3-5 year old classrooms in 50 ECE centers in North Carolina. Center teachers and directors completed relevant portions of the EPAO-SR on multiple days according to a standardized protocol, and trained data collectors completed the EPAO for 4 days in the centers. Reliability and validity statistics calculated included percent agreement, kappa, correlation coefficients, coefficients of variation, deviations, mean differences, and intraclass correlation coefficients (ICC), depending on the response option of the item. Data demonstrated a range of reliability and validity evidence for the EPAO-SR instrument. Reporting from directors and classroom teachers was consistent and similar to the observational data. Items that produced strongest reliability and validity estimates included beverages served, outside time, and physical activity equipment, while items such as whole grains served and amount of teacher-led PA had lower reliability (observation and self-report) and validity estimates. To overcome lower reliability and validity estimates, some items need administration on multiple days. This study demonstrated appropriate reliability and validity evidence for use of the EPAO-SR in the field. The self-administered EPAO-SR is an advancement of the measurement of ECE

  3. Landscape Forsmark - data, methodology and results for SR-Site

    Energy Technology Data Exchange (ETDEWEB)

    Lindborg, Tobias (ed.) (Svensk Kaernbraenslehantering AB (Sweden))

    2010-12-15

    This report presents an integrated description of the landscape at the Forsmark site during the succession from present conditions to the far future. It was produced as a part of the biosphere modelling within the SR-Site safety assessment. The report gives a description of input data, methodology and resulting models used to support the current understanding of the landscape used in SR-Site. It is intended to describe the properties and conditions at the site and to give information essential for demonstrating understanding. The report relies heavily on a number of discipline-specific background reports concerning details of the data analyses and modelling. Long-term landscape development in the Forsmark area is dependent on two main and partly interdependent factors, i.e. climate variations and shoreline displacement. These two factors in combination strongly affect a number of processes, which in turn determine the development of ecosystems. Some examples of such processes are erosion and sedimentation, groundwater recharge and discharge, soil formation, primary production and decomposition of organic matter. The biosphere at the site during the next 1,000 years is assumed to be quite similar to the present situation. The most important changes are the natural infilling of lakes and a slight withdrawal of the sea with its effects on the near-shore areas and the shallow coastal basins. The climate during the rest of the temperate period may vary considerably, with both warmer and colder periods. The main effect of temperature changes will be on the vegetation period. Changed temperatures may give rise to drier or wetter climate and to changed snow cover and frost characteristics, and this can in turn affect the dominant vegetation and mire build-up. The description of the Forsmark ecosystem succession during a glacial cycle is one of the main features of the SR-Site biosphere modelling. The future areas potentially affected by deep groundwater discharge are

  4. Fabricating superconducting interfaces between artificially grown LaAlO3 and SrTiO3 thin films

    Directory of Open Access Journals (Sweden)

    Danfeng Li

    2014-01-01

    Full Text Available Realization of a fully metallic two-dimensional electron gas (2DEG at the interface between artificially grown LaAlO3 and SrTiO3 thin films has been an exciting challenge. Here we present for the first time the successful realization of a superconducting 2DEG at interfaces between artificially grown LaAlO3 and SrTiO3 thin films. Our results highlight the importance of two factors—the growth temperature and the SrTiO3 termination. We use local friction force microscopy and transport measurements to determine that in normal growth conditions the absence of a robust metallic state at low temperature in the artificially grown LaAlO3/SrTiO3 interface is due to the nanoscale SrO segregation occurring on the SrTiO3 film surface during the growth and the associated defects in the SrTiO3 film. By adopting an extremely high SrTiO3 growth temperature, we demonstrate a way to realize metallic, down to the lowest temperature, and superconducting 2DEG at interfaces between LaAlO3 layers and artificially grown SrTiO3 thin films. This study paves the way to the realization of functional LaAlO3/SrTiO3 superlattices and/or artificial LaAlO3/SrTiO3 interfaces on other substrates.

  5. Processing and Characterization of SrTiO₃-TiO₂ Nanoparticle-Nanotube Heterostructures on Titanium for Biomedical Applications.

    Science.gov (United States)

    Wang, Yu; Zhang, Dongmei; Wen, Cuie; Li, Yuncang

    2015-07-29

    Surface properties such as physicochemical characteristics and topographical parameters of biomaterials, essentially determining the interaction between the biological cells and the biomaterial, are important considerations in the design of implant materials. In this study, a layer of SrTiO3-TiO2 nanoparticle-nanotube heterostructures on titanium has been fabricated via anodization combined with a hydrothermal process. Titanium was anodized to create a layer of titania (TiO2) nanotubes (TNTs), which was then decorated with a layer of SrTiO3 nanoparticles via hydrothermal processing. SrTiO3-TiO2 heterostructures with high and low volume fraction of SrTiO3 nanoparticle (denoted by 6.3-Sr/TNTs and 1.4-Sr/TNTs) were achieved by using a hydrothermal processing time of 12 and 3 h, respectively. The in vitro biocompatibility of the SrTiO3-TiO2 heterostructures was assessed by using osteoblast cells (SaOS2). Our results indicated that the SrTiO3-TiO2 heterostructures with different volume fractions of SrTiO3 nanoparticles exhibited different Sr ion release in cell culture media and different surface energies. An appropriate volume fraction of SrTiO3 in the heterostructures stimulated the secretion of cell filopodia, leading to enhanced biocompatibility in terms of cell attachment, anchoring, and proliferation on the heterostructure surface.

  6. Geochemical implications from Sr isotopes and K-Ar age determinations for the cook-austral islands chain

    Science.gov (United States)

    Matsuda, Jun-Ichi; Notsu, Kenji; Okano, Jun; Yaskawa, Katsumi; Chungue, Leonard

    1984-04-01

    Sr isotopes and K-Ar ages were determined for volcanic rocks from three islands, Samoa, Rarotonga and Rurutu in the Austral-Gilbert-Marshall chain. We have established that Rurutu originated from the same "hot spot" as Tubuai and Raivavae in the Cook-Austral chain as indicated by its 11 m.y. K-Ar age and ( {87Sr }/{86Sr }) ratios. The ( {87Sr }/{86Sr }) ratios for Rurutu, Tubuai and Raivavae lie in the restricted range 0.7026-0.7035. K-Ar ages of all volcanic rocks from Samoa and Rarotonga are all less than 4 m.y. and their ( {87Sr }/{86Sr }) ratios are much higher than those in Rurutu, Tubuai and Raivavae. These findings suggest that Samoa and Rarotonga did not originate in a single hot spot for the Cook-Austral islands.

  7. The effect of silver doping on the critical current density of Bi-Pb-Sr-Ca-Cu-O ceramic superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Zargar Shoushtari, M.; Bahrami, Amir; Farbod, Mansoor [Department of Physics, College of Science, Shahid Chamran University, Ahvaz (Iran)

    2006-09-15

    In this research, the effect of silver doping on Bi{sub 1.6}Pb{sub 0.4}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub y} ceramic superconductor has been investigated. The solid-state reaction method and two different silver doping methods has been used, namely, doping during making processes of samples (batch 1) and doping after making Bi{sub 1.6}Pb{sub 0.4}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub y} superconductor (batch 2). We observed that by adding silver to BPSCCO compound, partial melting temperature of the compound is decreased. The critical current density (J{sub c}) in both batches is affected by Ag doping. The investigation of SEM images of samples has shown that the all surfaces of the samples are porous and the grains are plate like. It seems that the BPSCCO grains in batch 1 samples are coated with silver but in the samples of batch 2, the silver also sits between the BPSCCO grains. The XRD patterns studies indicated that the silver peaks form separate phase and also by adding silver to BSCCO, the BPSCCO peaks do not show considerable shift. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  8. Sorting Test, Tower Test, and BRIEF-SR do not predict school performance of healthy adolescents in preuniversity education

    Science.gov (United States)

    Boschloo, Annemarie; Krabbendam, Lydia; Aben, Aukje; de Groot, Renate; Jolles, Jelle

    2014-01-01

    Executive functions (EF) such as self-monitoring, planning, and organizing are known to develop through childhood and adolescence. They are of potential importance for learning and school performance. Earlier research into the relation between EF and school performance did not provide clear results possibly because confounding factors such as educational track, boy-girl differences, and parental education were not taken into account. The present study therefore investigated the relation between executive function tests and school performance in a highly controlled sample of 173 healthy adolescents aged 12–18. Only students in the pre-university educational track were used and the performance of boys was compared to that of girls. Results showed that there was no relation between the report marks obtained and the performance on executive function tests, notably the Sorting Test and the Tower Test of the Delis-Kaplan Executive Functions System (D-KEFS). Likewise, no relation was found between the report marks and the scores on the Behavior Rating Inventory of Executive Function—Self-Report Version (BRIEF-SR) after these were controlled for grade, sex, and level of parental education. The findings indicate that executive functioning as measured with widely used instruments such as the BRIEF-SR does not predict school performance of adolescents in preuniversity education any better than a student's grade, sex, and level of parental education. PMID:24782794

  9. Sorting Test, Tower Test and BRIEF-SR do not predict school performance of healthy adolescents in preuniversity education

    Directory of Open Access Journals (Sweden)

    Annemarie eBoschloo

    2014-04-01

    Full Text Available Executive functions (EF such as self-monitoring, planning and organizing are known to develop through childhood and adolescence. They are of potential importance for learning and school performance. Earlier research into the relation between executive functions and school performance did not provide clear results possibly because confounding factors such as educational track, boy-girl differences and parental education were not taken into account. The present study therefore investigated the relation between executive function tests and school performance in a highly controlled sample of 173 healthy adolescents aged 12-18. Only students in the pre-university educational track were used and the performance of boys was compared to that of girls. Results showed that there was no relation between the report marks obtained and the performance on executive function tests, notably the Sorting Test and the Tower Test of the Delis-Kaplan Executive Functions System (D-KEFS. Likewise, no relation was found between the report marks and the scores on the Behavior Rating Inventory of Executive Function – Self-Report Version (BRIEF-SR after these were controlled for grade, sex, and level of parental education.The findings indicate that executive functioning as measured with widely used instruments such as the BRIEF-SR does not predict school performance of adolescents in preuniversity education any better than a student’s grade, sex, and level of parental education. ed

  10. Review of the Constellation Level II Safety, Reliability, and Quality Assurance (SR&QA) Requirements Documents during Participation in the Constellation Level II SR&QA Forum

    Science.gov (United States)

    Cameron, Kenneth D.; Gentz, Steven J.; Beil, Robert J.; Minute, Stephen A.; Currie, Nancy J.; Scott, Steven S.; Thomas, Walter B., III; Smiles, Michael D.; Schafer, Charles F.; Null, Cynthia H.; hide

    2009-01-01

    At the request of the Exploration Systems Mission Directorate (ESMD) and the Constellation Program (CxP) Safety, Reliability; and Quality Assurance (SR&QA) Requirements Director, the NASA Engineering and Safety Center (NESC) participated in the Cx SR&QA Requirements forum. The Requirements Forum was held June 24-26; 2008, at GRC's Plum Brook Facility. The forums purpose was to gather all stakeholders into a focused meeting to help complete the process of refining the CxP to refine its Level II SR&QA requirements or defining project-specific requirements tailoring. Element prime contractors had raised specific questions about the wording and intent of many requirements in areas they felt were driving costs without adding commensurate value. NESC was asked to provide an independent and thorough review of requirements that contractors believed were driving Program costs, by active participation in the forum. This document contains information from the forum.

  11. Tuning La0.67Sr0.33MnO3 surface magnetism using LaMnO3 and SrTiO3 caps

    Science.gov (United States)

    Phillips, L. C.; Maccherozzi, F.; Moya, X.; Ghidini, M.; Yan, W.; Soussi, J.; Dhesi, S. S.; Mathur, N. D.

    2014-04-01

    We have investigated how the surface magnetism of epitaxial La0.67Sr0.33MnO3 films on NdGaO3 substrates is modified by 2 nm-thick caps of the undoped manganite LaMnO3 and the band insulator SrTiO3. Low-temperature photoemission electron microscopy images with x-ray magnetic circular dichroism contrast reveal large ferromagnetic domains, and a reduction of surface Curie temperature by 40 K (LaMnO3 cap) and 70 K (SrTiO3 cap). We use these negative results to argue that capped films of sub-optimally doped La1-xSrxMnO3 (x≠0.33) should improve the operating temperature of all-oxide and other spintronic devices.

  12. Tuning the dead-layer behavior of La0.67Sr0.33MnO3/SrTiO3 via interfacial engineering

    Science.gov (United States)

    Peng, R.; Xu, H. C.; Xia, M.; Zhao, J. F.; Xie, X.; Xu, D. F.; Xie, B. P.; Feng, D. L.

    2014-02-01

    The dead-layer behavior, deterioration of the bulk properties in near-interface layers, restricts the applications of many oxide heterostructures. We present the systematic study of the dead-layer in La0.67Sr0.33MnO3/SrTiO3 grown by ozone-assisted molecular beam epitaxy. Dead-layer behavior is systematically tuned by varying the interfacial doping, while unchanged with varied doping at any other atomic layers. In situ photoemission and low energy electron diffraction measurements suggest intrinsic oxygen vacancies at the surface of ultra-thin La0.67Sr0.33MnO3, which are more concentrated in thinner films. Our results show correlation between interfacial doping, oxygen vacancies, and the dead-layer, which can be explained by a simplified electrostatic model.

  13. Recoil distance method lifetime measurement of the 21+ state in 94Sr and implications for the structure of neutron-rich Sr isotopes

    Science.gov (United States)

    Chester, A.; Ball, G. C.; Caballero-Folch, R.; Cross, D. S.; Cruz, S.; Domingo, T.; Drake, T. E.; Garnsworthy, A. B.; Hackman, G.; Hallam, S.; Henderson, J.; Henderson, R.; Korten, W.; Krücken, R.; Moukaddam, M.; Olaizola, B.; Ruotsalainen, P.; Smallcombe, J.; Starosta, K.; Svensson, C. E.; Williams, J.; Wimmer, K.

    2017-07-01

    A high precision lifetime measurement of the 21+ state in 94Sr was performed at TRIUMF's ISAC-II facility by coupling the recoil distance method implemented via the TIGRESS integrated plunger with unsafe Coulomb excitation in inverse kinematics. Due to limited statistics imposed by the use of a radioactive 94Sr beam, a likelihood ratio χ2 method was derived and used to compare experimental data to Geant4 simulations. The B (E 2 ;21+→01+) value extracted from the lifetime measurement of 7 .80-0.40+0.50(stat.)±0.07 (sys.) ps is approximately 25% larger than previously reported while the relative error has been reduced by a factor of approximately 8. A baseline deformation has been established for Sr isotopes with N ≤58 which is a necessary condition for the quantum phase transition interpretation of the onset of deformation in this region. A comparison to existing theoretical models is presented.

  14. International Expert Review of Sr-Can: Safety Assessment Methodology - External review contribution in support of SSI's and SKI's review of SR-Can

    Energy Technology Data Exchange (ETDEWEB)

    Sagar, Budhi (Center for Nuclear Waste Regulatory Analyses, Southwest Research Inst., San Antonio, TX (US)); Egan, Michael (Quintessa Limited, Henley-on-Thames (GB)); Roehlig, Klaus-Juergen (Gesellschaft fuer Anlagen- und Reaktorsicherheit mbH (DE)); Chapman, Neil (Independent Consultant (XX)); Wilmot, Roger (Galson Sciences Limited, Oakham (GB))

    2008-03-15

    In 2006, SKB published a safety assessment (SR-Can) as part of its work to support a licence application for the construction of a final repository for spent nuclear fuel. The purposes of the SR-Can project were stated in the main project report to be: 1. To make a first assessment of the safety of potential KBS-3 repositories at Forsmark and Laxemar to dispose of canisters as specified in the application for the encapsulation plant. 2. To provide feedback to design development, to SKB's research and development (R and D) programme, to further site investigations and to future safety assessments. 3. To foster a dialogue with the authorities that oversee SKB's activities, i.e. the Swedish Nuclear Power Inspectorate, SKI, and the Swedish Radiation Protection Authority, SSI, regarding interpretation of applicable regulations, as a preparation for the SR-Site project. To help inform their review of SKB's proposed approach to development of the longterm safety case, the authorities appointed three international expert review teams to carry out a review of SKB's SR-Can safety assessment report. Comments from one of these teams - the Safety Assessment Methodology (SAM) review team - are presented in this document. The SAM review team's scope of work included an examination of SKB's documentation of the assessment ('Long-term safety for KBS-3 Repositories at Forsmark and Laxemar - a first evaluation' and several supporting reports) and hearings with SKB staff and contractors, held in March 2007. As directed by SKI and SSI, the SAM review team focused on methodological aspects and sought to determine whether SKB's proposed safety assessment methodology is likely to be suitable for use in the future SR-Site and to assess its consistency with the Swedish regulatory framework. No specific evaluation of long-term safety or site acceptability was undertaken by any of the review teams. SKI and SSI's Terms of Reference for the SAM

  15. Sr/Ca and Mg/Ca in Glycymeris glycymeris (Bivalvia) shells from the Iberian upwelling system: Ontogeny and environmental control

    Science.gov (United States)

    Freitas, Pedro; Richardson, Christopher; Chenery, Simon; Monteiro, Carlos; Butler, Paul; Reynolds, David; Scourse, James; Gaspar, Miguel

    2017-04-01

    /Ca variation in older shells was synchronous with contemporary environmental conditions, i.e. upwelling intensity and salinity. The use of Sr or Mg in G. glycymeris shells as valid geochemical environmental proxies in the Iberian Upwelling System remains complex and requires further research to unravel environmental and physiological/biomineralization controls. This study was financed by the Portuguese Fundação para a Ciência e Tecnologia (FCT) GLYCY Project (contract PTDC/AAC-CLI/118003/2010) and a sabbatical grant to PSF (Ref: SFRH/BSAB/127786/2016), co-supported by POCH and the European Social Fund. Funding for consumable costs was provided by Bangor University.

  16. Syntheses, crystal structures, NMR spectroscopy, and vibrational spectroscopy of Sr(PO{sub 3}F).H{sub 2}O and Sr(PO{sub 3}F)

    Energy Technology Data Exchange (ETDEWEB)

    Jantz, Stephan G.; Hoeppe, Henning A. [Lehrstuhl fuer Festkoerperchemie, Institut fuer Physik, Universitaet Augsburg (Germany); Wuellen, Leo van; Fischer, Andreas [Lehrstuhl fuer Chemische Physik und Materialwissenschaften, Institut fuer Physik, Universitaet Augsburg (Germany); Libowitzky, Eugen [Institute for Mineralogy and Crystallography, Faculty of Geosciences, Geography and Astronomy, University of Vienna (Austria); Baran, Enrique J. [Centro de Quimica Inorganica (CEQUINOR/CONICET, UNLP), Facultad de Ciencias Exactas, Universidad Nacional de La Plata (Argentina); Weil, Matthias [Institute for Chemical Technologies and Analytics, Division Structural Chemistry, Vienna University of Technology (Austria)

    2016-03-15

    Single crystals of Sr(PO{sub 3}F).H{sub 2}O {P2_1/c, Z = 4, a = 7.4844(2) Aa, b = 7.0793(2) Aa, c = 8.4265(2) Aa, β = 108.696(1) , V = 422.91(2) Aa"3, 2391 F_o"2, 70 parameters, R_1[F"2 > 2σ(F"2)] = 0.036; wR_2(F"2 all) = 0.049, S = 1.054} were grown from an aqueous solution by a metathesis reaction. The structure comprises [SrO{sub 8}] polyhedra and PO{sub 3}F tetrahedra that form a layered arrangement parallel to (100). The topotactic dehydration of this phase proceeds between 80 and 140 C to afford Sr(PO{sub 3}F). The monazite-type crystal structure of Sr(PO{sub 3}F) was elucidated from the X-ray powder data by simulated annealing [P2{sub 1}/c, Z = 4, a = 6.71689(9) Aa, b = 7.11774(11) Aa, c = 8.66997(13) Aa, β = 128.0063(7) , V = 326.605(8) Aa{sup 3}, R{sub p} = 0.010, R{sub wp} = 0.015, R{sub F} = 0.030]. During dehydration, the structure of Sr(PO{sub 3}F) .H{sub 2}O collapses along [100] from a layered arrangement into a framework structure, accompanied by a change of the coordination number of the Sr{sup 2+} ions from eight to nine. The magic-angle spinning (MAS) NMR and vibrational spectroscopy data of both phases are discussed. (Copyright copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  17. Inflight alignment and calibration of SR-POEM

    Science.gov (United States)

    Reasenberg, Robert; Phillips, James

    2015-04-01

    We are developing SR-POEM, a payload for detecting a possible violation of the weak equivalence principle (WEP) while on the free-fall trajectory of a sounding-rocket payload. We estimate an uncertainty of σ(η) <=10-17 from a single flight. The experiment consists of calibration maneuvers plus eight 120 s drops of the two test masses (TMs). The instrument orientation will be reversed between successive drops, which reverses the signal but leaves most systematic errors unchanged. The TMs are unconstrained during drops. They are surrounded by capacitance plates that allow both measurement and control of TM position and orientation with respect to the physics package. The calibration maneuvers are carried out both before and after the series of drops. The pre-drop calibration maneuvers define the ``centering'' of the TMs, nominally at the payload center of mass. Each of the eight drops then starts with nonmoving TMs precisely at this location. The post-drop calibration maneuvers detect changes in the location of the payload center of mass and serve to bound the corresponding contribution to systematic error.

  18. Reduction of magnetic perturbation for SR-POEM

    Science.gov (United States)

    Patla, B. R.

    2016-02-01

    SR-POEM is a Galilean test of the weak equivalence principle that aims to measure the fractional acceleration difference η with a mission uncertainty σ (η )=1× {10}-17 for a pair of test substances. It is to be conducted during the low-drag free fall portion of a sounding rocket flight. The interaction of the magnetic field gradient with tiny remanent magnetic moments of the test masses will produce a spurious acceleration that is not sufficiently reduced by a single Mu-metal shield. In this paper, we study configurations with two and three shields. Approximate analytic formulae are used to study the shielding factor as a function of geometry. We use finite element analysis (FEA) to determine the magnetic field and gradient for certain cases that satisfy the mission requirements. FEA results are compared with analytic expressions wherever appropriate. Several configurations reduce both axial and transverse magnetic field within the shielding volume by at least the required factor of 4× {10}5.

  19. Evolution of magnetic oxygen states in Sr-doped LaCoO3.

    Science.gov (United States)

    Medling, S; Lee, Y; Zheng, H; Mitchell, J F; Freeland, J W; Harmon, B N; Bridges, F

    2012-10-12

    Magnetism in La(1-x)Sr(x)CoO(3) as a function of doping is investigated with x-ray absorption spectroscopy and x-ray magnetic circular dicrhoism at the O K edge, and corresponding first principles electronic structure calculations. For small x, the spectra are consistent with the formation of ferromagnetic clusters occurring within a nonmagnetic insulating matrix. Sr-induced, magnetic O-hole states form just above E(F) and grow with increasing Sr doping. Density functional calculations for x=0 yield a nonmagnetic ground state with the observed rhombohedral distortion and indicates that doping introduces holes at the Fermi level in magnetic states with significant O 2p and Co t(2g) character for the undistorted pseudocubic structure. Supercell calculations show stronger magnetism on oxygen atoms having more Sr neighbors.

  20. Measurement of Ca, Zn and Sr in enamel of human teeth by XRF

    Energy Technology Data Exchange (ETDEWEB)

    Wielopolski, L.; Featherstone, J.D.B.; Cohn, S.H.

    1984-01-01

    Energy dispersive x-ray fluorescence (EDXRF) has been employed to measure Ca, Zn, and Sr in enamel of human teeth. The calibration of the EDXRF system was performed by comparing Sr/Ca ratios with values obtained by atomic absorption analysis of acid etched biopsies of the enamel surface. Two calibration lines were obtained, one line for untreated teeth and the second line for teeth immersed (treated) in solutions containing Sr. A simple analytical model demonstrated that the two calibration lines were the result of the difference in the depth of the enamel sampled by EDXRF and by the acid-etched biopsy. The multi-elemental, non-destructive and quantitative aspects of EDXRF permit the sequential monitoring of the effects of Sr and Zn ions on the mineralization and demineralization processes in human enamel. The portability of the system and adaptability to non-invasive measurements makes it suitable for field studies. 26 references, 4 figures.