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Sample records for al ph salinidad

  1. Efecto de la salinidad en la supervivencia embrionaria de puye Galaxias maculatus (Jenyns, 1842

    Directory of Open Access Journals (Sweden)

    Juan Barile

    2015-05-01

    Full Text Available Se evaluó e l efecto de la salinidad en la supervivencia embrionaria, período embrionario y período de eclosión de puye, Galaxias maculatus. Se utilizaron ocho tratamientos, con salinidades de 0, 4, 8, 12, 16 y 20 obteniéndose supervivencias embrionarias promedios respectivas de 84,9; 84,0; 85,5; 86,1; 82,6 y 75,8%, sin diferencias significativas entre ellas, mientras que con salinidad de 24 se obtuvo sobrevivencia de 10,4%, significativamente diferente al resto de los tratamientos y con salinidad de 28 causó 100% de mortalidad. A diferencia del estado juvenil y adulto, el embrión es incapaz de resistir la salinidad marina y su umbral de tolerancia se encuentra entre salinidades de 24 y 28. Las mayores supervivencias promedios larvales a 10 días de vida fueron con salinidades intermedias de 8, 12 y 16 de 79,3; 80,3 y 74,6% respectivamente, sin diferencias significativas entre ellas, demostrando alta viabilidad del embrión post-eclosión. Los períodos embrionarios promedios (50% más breves fueron a bajas salinidades 0, 4, 8, 12 con 28,7; 28,0; 29,7 y 29,7 días y los más extensos en los tratamientos con salinidades de 16 y 20, con 34,0 y 34,3 días, sin diferencias significativas entre ellos. Los períodos de eclosión promedio (50% con salinidades de 0, 4, 8, 12, 16, 20 y 24 fueron de 5,0; 5,5; 7,5; 8,8; 13,0; 14,3 y 15,8 días respectivamente, sin diferencias significativas entre ellos.

  2. The Al(I) molecule, Ph2COAl and its anion

    Science.gov (United States)

    Zhang, Xinxing; Eichhorn, Bryan; Schnöckel, Hansgeorg; Bowen, Kit

    2016-08-01

    We have formed the Al(I)-containing molecule, benzophenone-aluminum, i.e., Ph2COAl, and studied it by conducting density functional theory calculations on both its neutral and anionic forms and by measuring the photoelectron spectrum of its anion. Our calculations identified two nearly iso-energetic anion isomers, (Ph2COAl)-, the vertical detachment energies (VDE) of which are in excellent agreement with our photoelectron spectrum. Natural population analysis (NPA) of Ph2COAl found the Al moiety to be positively charged by +0.81 e, indicating a strongly ionic bond between Al and Ph2CO, i.e., Ph2CO-Al+.

  3. La crisis de salinidad del Messiniense

    OpenAIRE

    Soria Mingorance, Jesús Miguel

    2007-01-01

    La crisis de salinidad del Messiniense es un acontecimiento mayor en la evolución del Mediterráneo que se caracteriza por la precipitación de evaporitas tanto en sus llanuras abisales como en las cuencas marginales. Las evaporitas están compuestas principalmente por yeso, anhidrita y halita, indicando unas condiciones de depósito marinas extremadamente someras. A raíz del hallazgo de evaporitas en las llanuras abisales se derivó la hipótesis de cuenca profunda desecada, según la cual durante ...

  4. Selective formation of the [PhP(H)-PPh]- anion in the reaction of PhPHLi with MeAlCl(2); synthesis and structure of the unusual tetramer [(PhP(H)-PPh)Li.thf]4.

    Science.gov (United States)

    Garcia, Felipe; Humphrey, Simon M; Kowenicki, Richard A; McPartlin, Mary; Wright, Dominic S

    2004-04-01

    The reaction of PhPHLi with MeAlCl(2)(3:1 equivalents) gives the tetramer [(PhP(H)-PPh)Li.thf]4, and provides the first direct evidence of a link between the reactivity patterns observed for Group 14 and 15 phosphanenides and those of Group 13.

  5. RESPUESTA DE 12 VARIEDADES DE TRIGO A LA SALINIDAD EN LAS ETAPAS INICIALES DEL CRECIMIENTO

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    L. Argentel

    2006-01-01

    Full Text Available Con el objetivo de analizar la respuesta varietal del cultivo de trigo a la salinidad en las etapas iniciales del crecimiento de las plántulas, se montó un experimento con 12 variedades, aplicando dos niveles de NaCl en la solución. Las variables evaluadas fueron la absorción de agua por las semillas, altura de las plantas y longitud de la raíz, y la acumulación de biomasas fresca y seca. Mediante un análisis de componentes principales, se establecieron los indicadores de mayor contribución a la diferenciación varietal y a través del análisis de Conglomerados Jerárquico, el material fue reunido en tres grupos, lo que demuestra la existencia de variabilidad en cuanto a su respuesta al estrés. Cinco mutantes de la variedad CubaC-204 se reunieron en el grupo I, que mostró la mayor respuesta a la salinidad en estadios tempranos del desarrollo del cultivo, los cuales comenzarán a evaluarse sobre la base del rendimiento y sus componentes.

  6. [Short-term changes of pH value and Al activity in acid soils after urea fertilization].

    Science.gov (United States)

    Zeng, Qingru; Liao, Bohan; Jiang, Zhaohui; Zhou, Xihong; Tang, Can; Zhong, Ning

    2005-02-01

    Acidic soils are widely distributed in South China, and their acidity is the major environmental stress factor limiting the growth of most crops. It is well known that soil Al solubilized at low pH is a main toxic factor for plant growth. Our study with three acidic soils showed that soil pH increased quickly, while soil exchangeable Al decreased sharply with the increasing concentrations of applied urea. The time-course experiment revealed that the increase of soil pH was short-lived, with a subsequently slow drop after reached its maximum. Urea fertilization caused a drastic change of soil pH during 2-4 weeks of the experimental period. There was a negative relationship between soil pH and soil exchangeable Al. Biological toxicity test demonstrated that applying urea to acidic soils could obviously decrease the aluminum toxicity of maize in a short-term period.

  7. Surface activity evaluation of an arabinose ester as water/oil demulsifier at severe conditions of temperature, salinity and pH; Avaliacao da atividade superficial de um ester de arabinose, como desemulsificante agua/oleo, em condicoes severas de temperatura, salinidade e pH

    Energy Technology Data Exchange (ETDEWEB)

    Borges, Mauricio Rodrigues; Garcia, Rosangela Balaban; Santos, Jaciara Alves dos; Vieira, Mariane; Silva, Luciana Carvalho; Campos, Viviane de Oliveira; Silva, Rayane Araujo da; Santos, Telma Pitanga dos [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2008-07-01

    This work had for objective to compare the superficial properties of an arabinose ester, no-ionic, nontoxic, biodegradable, with two commercial products: the first one based on sodium dodecyl sulfate and the second one based on poly-oxy alkylene phenol formaldehyde. The arabinose ester was synthesized on the Petroleum Research Laboratory - UFRN, through enzymatic catalysis by protease from Bacillus subtilis, using arabinose and vegetable oil, in organic medium. In previous work [1], this sugar ester was evaluated as a possible water/oil demulsifier and the results were compared with the results of the commercial product based on poly-oxy alkylene phenol formaldehyde, showing that, for certain reaction conditions, the sugar ester presented better acting (71%) that the commercial product (33%) as demulsifier. In this work, the stability of this arabinose ester was evaluated in severe conditions of temperature, salinity and pH, through superficial tests in a tensiometer, using Wilhelmy plate method and the results were compared with the results obtained for two commercial products above mentioned. (author)

  8. RESPUESTA DIFERENCIAL A LA SALINIDAD DE GENOTIPOS DE TOMATE (Lycopersicon esculentum Mill. EN PRIMERAS ETAPAS FENOLÓGICAS

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    Francisco Higinio Ruiz Espinoza

    2014-09-01

    Full Text Available La salinidad afecta tanto el crecimiento vegetativo como el desarrollo reproductivo de las plantas: puede reducir el número de flores, incrementar la esterilidad y alterar la duración de la floración y la maduración. En México, el tomate es una de las especies hortícolas de mayor importancia económica y social, en virtud del valor de su producción y por la demanda de mano de obra que genera, por lo que el objetivo del presente trabajo fue evaluar el efecto de la salinidad en variables morfológicas, en dos etapas fenológicas (germinación y crecimiento vegetativo inicial, de ocho genotipos de tomate, “Tropic, Feroz, Ace, Super Río Grande, Yaqui, Missouri, Vita y Floradade”, los cuales fueron expuestos a estrés salino mediante la adición de NaCl en concentraciones de 0, 50, 100, 150 y 200 mM, en un diseño experimental completamente al azar con cuatro repeticiones. En la etapa de germinación se midieron las variables morfométricas: porcentaje de germinación, peso fresco y seco de parte aérea, peso fresco de raíces. En la etapa de crecimiento vegetativo inicial se midieron: longitud de tallo, peso fresco de tallo, numero de hojas y área foliar. Los resultados de la etapa de germinación muestran que conforme se incrementó la concentración salina, el porcentaje de germinación disminuyó, siendo “Tropic y Yaqui” los que mostraron valores superiores. Por su parte, “Tropic y Missouri” mostraron el mayor peso fresco y seco de parte aérea, mientras que los genotipos con menor tolerancia en esta etapa fueron “Feroz, Vita y Ace”. En la etapa de crecimiento vegetativo inicial se determinó que los cultivares que presentaron mejor respuesta o mayor tolerancia al estrés salino fueron “Missouri, Tropic, Feroz y Vita”, mientras que los genotipos con menor tolerancia a la salinidad en esta etapa fueron “Floradade y Ace”. Se concluye que en ambas etapas fenológicas existe un diferencial potencial entre los

  9. Fractionation of residual Al in natural water treatment from reservoir with poly-aluminum-silicate-chloride (PASiC): Effect of OH/Al,Si/Al molar ratios and initial pH

    Institute of Scientific and Technical Information of China (English)

    Zhonglian Yang; Baoyu Gao; Yan Wang; Yaqin Zhao; Qinyan Yue

    2012-01-01

    An aluminum fractionation study was conducted for a surface reservoir water treatment to understand the performance of polyaluminum-silicate-chloride (PASiC) in terms of the residual Al fractions as a function of initial pH.The coagulation performance expressed as turbidity and organic matter removal was established as supporting data.Some extra data were evaluated in terms of the residual Al ratio of the composite PASiC coagulant.The main residual Al sources were the Al fractions derived from the use of PASiC.The turbidity and organic matter removal ability was optimal at initial pH 6.00-7.00,while the concentrations of various residual Al species and the residual Al ratio of PASiC were minimal at an initial pH range of 7.00-8.00.Under the conditions of OH/Al molar ratio =2.00 and Si/Al molar ratio =0.05,PASiC had superior coagulation performance and comparatively low residual Al concentrations.The Al fraction in the composite PASiC coagulant seldom remained under such conditions.Experimental data also indicated that the suspended (filterable) Al fraction was the dominant species,and organic-bound or organo-Al complex Al was considered to be the major species of dissolved Al in water treated by PASiC coagulation.Additionally,the dissolved inorganic monomeric Al species dominated the dissolved monomeric Al fraction.

  10. Open-gated pH sensor fabricated on an undoped-AlGaN/GaN HEMT structure.

    Science.gov (United States)

    Abidin, Mastura Shafinaz Zainal; Hashim, Abdul Manaf; Sharifabad, Maneea Eizadi; Rahman, Shaharin Fadzli Abd; Sadoh, Taizoh

    2011-01-01

    The sensing responses in aqueous solution of an open-gated pH sensor fabricated on an AlGaN/GaN high-electron-mobility-transistor (HEMT) structure are investigated. Under air-exposed ambient conditions, the open-gated undoped AlGaN/GaN HEMT only shows the presence of a linear current region. This seems to show that very low Fermi level pinning by surface states exists in the undoped AlGaN/GaN sample. In aqueous solution, typical current-voltage (I-V) characteristics with reasonably good gate controllability are observed, showing that the potential of the AlGaN surface at the open-gated area is effectively controlled via aqueous solution by the Ag/AgCl gate electrode. The open-gated undoped AlGaN/GaN HEMT structure is capable of distinguishing pH level in aqueous electrolytes and exhibits linear sensitivity, where high sensitivity of 1.9 mA/pH or 3.88 mA/mm/pH at drain-source voltage, V(DS) = 5 V is obtained. Due to the large leakage current where it increases with the negative gate voltage, Nernstian like sensitivity cannot be determined as commonly reported in the literature. This large leakage current may be caused by the technical factors rather than any characteristics of the devices. Surprisingly, although there are some imperfections in the device preparation and measurement, the fabricated devices work very well in distinguishing the pH levels. Suppression of current leakage by improving the device preparation is likely needed to improve the device performance. The fabricated device is expected to be suitable for pH sensing applications.

  11. Open-Gated pH Sensor Fabricated on an Undoped-AlGaN/GaN HEMT Structure

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    Taizoh Sadoh

    2011-03-01

    Full Text Available The sensing responses in aqueous solution of an open-gated pH sensor fabricated on an AlGaN/GaN high-electron-mobility-transistor (HEMT structure are investigated. Under air-exposed ambient conditions, the open-gated undoped AlGaN/GaN HEMT only shows the presence of a linear current region. This seems to show that very low Fermi level pinning by surface states exists in the undoped AlGaN/GaN sample. In aqueous solution, typical current-voltage (I-V characteristics with reasonably good gate controllability are observed, showing that the potential of the AlGaN surface at the open-gated area is effectively controlled via aqueous solution by the Ag/AgCl gate electrode. The open-gated undoped AlGaN/GaN HEMT structure is capable of distinguishing pH level in aqueous electrolytes and exhibits linear sensitivity, where high sensitivity of 1.9 mA/pH or 3.88 mA/mm/pH at drain-source voltage, VDS = 5 V is obtained. Due to the large leakage current where it increases with the negative gate voltage, Nernstian like sensitivity cannot be determined as commonly reported in the literature. This large leakage current may be caused by the technical factors rather than any characteristics of the devices. Surprisingly, although there are some imperfections in the device preparation and measurement, the fabricated devices work very well in distinguishing the pH levels. Suppression of current leakage by improving the device preparation is likely needed to improve the device performance. The fabricated device is expected to be suitable for pH sensing applications.

  12. Evaluación de la salinidad potencial de aguas para riego en la cuenca del Cauto

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    Sandro Ricardo Palacio

    2010-01-01

    Full Text Available Se presentó la evaluación de la Salinidad Potencial (SP del agua procedente de la Estación de Bombeo Ingenio Viejo situada en la Cuenca del Cauto la que es utilizada para el riego en parte de las áreas agrícolas de la Empresa Antonio Maceo, a partir del análisis químico realizado por la Empresa de Aprovechamiento de Recursos Hidráulicos de Holguín. Se obtuvo un índice de (SP de 8.77, el cual la metodología lo indica como aguas condicionales para el riego por lo que debe mantenerse control sobre el comportamiento químico del suelo ya que se encuentra dentro del rango 3-15 según la metodología empleada. El índice considera que se produjo la precipitación de las sales menos solubles, quedando en solución los cloruros y sulfatos, con lo que aumentó considerablemente la presión osmótica sobre el suelo a bajos niveles de humedad, representando un peligro para zonas tendentes a la salinidad como lo es la zona de estudio, debido a su origen geológico. Se recomienda un tratamiento adecuado para su uso y manejo en la agricultura si se pretenden alcanzar mejores resultados sin agredir al medio ambiente.

  13. Efectos de la salinidad sobre el desarrollo de embriones de Cryphiops caementarius (Crustacea: Palaemonidae incubados in vitro

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    Adelhi S. Fuentes

    2011-05-01

    Full Text Available El objetivo fue estudiar los efectos de la salinidad sobre el desarrollo de embriones de Cryphiops caementa- rius incubados in vitro. Se utilizaron embriones de desarrollo temprano procedentes de una sola hembra. Se emplearon incubadoras de 400 mL, con 4 tratamientos de salinidades de 0, 10, 20 y 30‰, tres replicas, y 200 embriones cada incubadora. El 80% del agua se renovó frecuentemente. Las salinidades entre 0 y 30‰ no afectaron el desarrollo de los embriones hasta el estadio 6. Las salinidades de 10 y 20‰ ocasionaron retraso del desarrollo de los estadios 7 y 8; y la salinidad de 30‰ ocasionó muerte del estadio 7. En agua dulce el 70,3% de los embriones supervivieron y las larvas fueron normales; en cambio en salinidad de 10‰ el 13,5% y en 20‰ solo 7,9% lograron eclosionar larvas pero con deformaciones.

  14. The path ahead for MD/PhD programs in Canada Commentary on Jones et al.

    Science.gov (United States)

    Rosenblum, Norman D

    2016-01-01

    The paper by Jones and colleagues, published in this edition of Clinical Investigative Medicine, contributes to our understanding of Canadian MD/PhD Programs. While there has been little published on this subject by the Canadian programs, themselves, this paper is the most recent in a series by leaders of the Clinical Investigator Trainee Association of Canada (CITAC). The authors are to be commended for their efforts and productivity. PMID:27619401

  15. The path ahead for MD/PhD programs in Canada Commentary on Jones et al.

    Science.gov (United States)

    Rosenblum, Norman D

    2016-09-11

    The paper by Jones and colleagues, published in this edition of Clinical Investigative Medicine, contributes to our understanding of Canadian MD/PhD Programs. While there has been little published on this subject by the Canadian programs, themselves, this paper is the most recent in a series by leaders of the Clinical Investigator Trainee Association of Canada (CITAC). The authors are to be commended for their efforts and productivity.

  16. Computerspielen als medial-kulturelle Praktik - Ein medienpädagogisch-kulturtheoretischer Zugang zum Phänomen Computerspielen

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    Sabrina Schrammel

    2009-03-01

    Full Text Available Gegenwärtig werden im medienpädagogischen Diskurs Computerspiele primär als Medienangebote thematisiert, wobei oftmals ausser Acht gelassen wird, dass Spielen eine kulturell geprägte, aktive und soziale Auseinandersetzung mit dem Spiel als Artefakt, Regelwerk und Geschichte impliziert. Im vorliegenden Beitrag wird vor dem Hintergrund bildungstheoretischer und lerntheoretischer Überlegungen ein methodisch-theoretischer Zugang entfaltet und präzisiert, der es erlaubt, Computerspiele als spezifisch situierte medial- kulturelle Praktik pädagogisch zu erfassen, zu beschreiben und zu analysieren. Werden Computerspiele und ihr Spielen als Transformation und Produktion von kulturellen Erfahrungen thematisiert, dann stellt sich die Frage nach der pädagogischen Dimension des Computerspiel(ens neu. Es eröffnet sich dabei ein Forschungsfeld, das nach differenzierter medienpädagogischer Herangehensweise verlangt. Der vorliegende medienpädagogisch-kulturtheoretische Zugang zum Phänomen Computerspielen baut auf den theoretischen Wurzeln der Spieleforschung auf und fasst das Spielen als medial-kulturelle Handlung.

  17. Computerspielen als medial-kulturelle Praktik - Ein medienpädagogisch-kulturtheoretischer Zugang zum Phänomen Computerspielen

    Directory of Open Access Journals (Sweden)

    Sabrina Schrammel

    2009-03-01

    Full Text Available Gegenwärtig werden im medienpädagogischen Diskurs Computerspiele primär als Medienangebote thematisiert, wobei oftmals ausser Acht gelassen wird, dass Spielen eine kulturell geprägte, aktive und soziale Auseinandersetzung mit dem Spiel als Artefakt, Regelwerk und Geschichte impliziert. Im vorliegenden Beitrag wird vor dem Hintergrund bildungstheoretischer und lerntheoretischer Überlegungen ein methodisch-theoretischer Zugang entfaltet und präzisiert, der es erlaubt, Computerspiele als spezifisch situierte medial-kulturelle Praktik pädagogisch zu erfassen, zu beschreiben und zu analysieren. Werden Computerspiele und ihr Spielen als Transformation und Produktion von kulturellen Erfahrungen thematisiert, dann stellt sich die Frage nach der pädagogischen Dimension des Computerspiel(ens neu. Es eröffnet sich dabei ein Forschungsfeld, das nach differenzierter medienpädagogischer Herangehensweise verlangt. Der vorliegende medienpädagogisch-kulturtheoretische Zugang zum Phänomen Computerspielen baut auf den theoretischen Wurzeln der Spieleforschung auf und fasst das Spielen als medial-kulturelle Handlung.

  18. EXAFS study of mercury(II) sorption to Fe- and Al-(hydr)oxides: I. Effects of pH

    Science.gov (United States)

    Kim, C.S.; Rytuba, J.J.; Brown, Gordon E., Jr.

    2004-01-01

    The study of mercury sorption products in model systems using appropriate in situ molecular-scale probes can provide detailed information on the modes of sorption at mineral/water interfaces. Such studies are essential for assessing the influence of sorption processes on the transport of Hg in contaminated natural systems. Macroscopic uptake of Hg(II) on goethite (??-FeOOH), ??-alumina (??-Al2O3), and bayerite (??-Al(OH)3) as a function of pH has been combined with Hg L III-edge EXAFS spectroscopy, FTIR spectroscopy, and bond valence analysis of possible sorption products to provide this type of information. Macroscopic uptake measurements show that Hg(II) sorbs strongly to fine-grained powders of synthetic goethite (Hg sorption density ??=0.39-0.42 ??mol/m2) and bayerite (??=0.39-0.44 ??mol/m2), while sorbing more weakly to ??-alumina (??=0.04-0.13 ??mol/m 2). EXAFS spectroscopy on the sorption samples shows that the dominant mode of Hg sorption on these phases is as monodentate and bidentate inner-sphere complexes. The mode of Hg(II) sorption to goethite was similar over the pH range 4.3-7.4, as were those of Hg(II) sorption to bayerite over the pH range 5.1-7.9. Conversion of the ??-Al2O3 sorbent to a bayerite-like phase in addition to the apparent reduction of Hg(II) to Hg(I), possibly by photoreduction during EXAFS data collection, resulted in enhanced Hg uptake from pH 5.2-7.8 and changes in the modes of sorption that correlate with the formation of the bayerite-like phase. Bond valence calculations are consistent with the sorption modes proposed from EXAFS analysis. EXAFS analysis of Hg(II) sorption products on a natural Fe oxyhydroxide precipitate and Al/Si-bearing flocculent material showed sorption products and modes of surface attachment similar to those for the model substrates, indicating that the model substrates are useful surrogates for the natural sediments. ?? 2003 Elsevier Inc. All rights reserved.

  19. EL CULTIVO DE CAMARÓN EN AGUA DE BAJA SALINIDAD CON ALIMENTO A BASE DE HARINA DE LOMBRIZ

    OpenAIRE

    Wenceslao Valenzuela-Quiñónez; Héctor Manuel Esparza-Leal; Eusebio Nava-Pérez; Gerardo Rodríguez Quiroz

    2012-01-01

    El cultivo del camarón en el estado de Sinaloa es una de las principales actividades en la región, ya que genera una gran cantidad de empleos como de divisas cada año. La alimentación del camarón es una parte esencial para tener una producción sana. Como un acercamiento inicial al crecimiento del camarón en agua de baja salinidad se probaron dos fórmulas a base de proteína animal en el alimento del camarón, con un 40% (APL1) y 20% (APL2) de proteína de lombriz, un alimento comercial y otro si...

  20. Efecto de la salinidad en la sobrevivencia de peces silvestres del género Chirostoma durante el transporte y mantenimiento en laboratorio

    OpenAIRE

    Guillermo Artemio Blancas-Arroyo; Rocío Frías-Sevilla; Eréndira De la Rosa-Pimentel; Virginia Suárez-Navarro; José Rodolfo Castro-Gómez; Javier Magaña-Morales

    2014-01-01

    Se comprobó el efecto de la salinidad en la sobrevivencia de peces silvestres del género Chirostoma, durante su transporte y aclimatación. Estos organismos son endémicos de México y conocidos como peces blancos y charales; los cuales se han caracterizado por su hipersensibilidad al manejo y su alto grado de estrés. Los modelos biológicos fueron dos especies de charales: Chirostoma jordani de Xochimilco cuenca de México y C. chapalae de Queréndaro subcuenca de Cuitzeo Michoacán. Se transportar...

  1. Oxygen diffusion in alpha-Al2O3. Ph.D. Thesis

    Science.gov (United States)

    Cawley, J. D.; Halloran, J. W.; Cooper, A. R.

    1984-01-01

    Oxygen self diffusion coefficients were determined in single crystal alpha-Al2O3 using the gas exchange technique. The samples were semi-infinite slabs cut from five different boules with varying background impurities. The diffusion direction was parallel to the c-axis. The tracer profiles were determined by two techniques, single spectrum proton activation and secondary ion mass spectrometry. The SIMS proved to be a more useful tool. The determined diffusion coefficients, which were insensitive to impurity levels and oxygen partial pressure, could be described by D = .00151 exp (-572kJ/RT) sq m/s. The insensitivities are discussed in terms of point defect clustering. Two independent models are consistent with the findings, the first considers the clusters as immobile point defect traps which buffer changes in the defect chemistry. The second considers clusters to be mobile and oxygen diffusion to be intrinsic behavior, the mechanism for oxygen transport involving neutral clusters of Schottky quintuplets.

  2. Fe/Al bimetallic particles for the fast and highly efficient removal of Cr(VI) over a wide pH range: Performance and mechanism

    International Nuclear Information System (INIS)

    Highlights: • Bimetallic particles with different Fe/Al mass ratios were prepared. • High removal rate of Cr(VI) was achieved in acidic, neutral, and alkaline pH. • No total iron ions at pH 3.0–11.0 and nearly no Al3+ at pH 3.0–7.0 were released. • Galvanic cell effect and high specific surface area contributed to Cr(VI) removal. - Abstract: The iron/aluminum (Fe/Al) bimetallic particles with high efficiency for the removal of Cr(VI) were prepared. Fe/Al bimetallic particles were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), SEM mapping, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). SEM mapping showed that the core of bimetal was Al, and the planting Fe was deposited on the surface of Al. In acidic and neutral conditions, Fe/Al bimetal can completely remove Cr(VI) from wastewater in 20 min. Even at pH 11.0, the Cr(VI) removal efficiency achieved was 93.5%. Galvanic cell effect and high specific surface area are the main reasons for the enhanced removal of Cr(VI) by bimetallic particles. There were no iron ions released in solutions at pH values ranging from 3.0 to 11.0. The released Al3+ ions concentrations in acidic and neutral conditions were all less than 0.2 mg/L. The bimetal can be used 4 times without losing activity at initial pH 3.0. XPS indicated that the removed Cr(VI) was immobilized via the formation of Cr(III) hydroxide and Cr(III)–Fe(III) hydroxide/oxyhydroxide on the surface of Fe/Al bimetal. The Fe/Al bimetallic particles are promising for further testing for the rapid and effective removal of contaminants from water

  3. Effect of pH on the Nitrite Hydrogenation Mechanism over Pd/Al2O3 and Pt/Al2O3: Details Obtained with ATR-IR Spectroscopy

    DEFF Research Database (Denmark)

    Ebbesen, Sune Dalgaard; Mojet, Barbara L.; Lefferts, Leon

    2011-01-01

    It is well-known that activity and selectivity to N2 during nitrite hydrogenation over noble metal catalysts in water depend on the pH of the solution, but mechanistic understanding is lacking. Attenuated total reflection infrared (ATR-IR) spectroscopy is an ideal tool to perform detailed studies...... on catalytic surfaces in water. In this paper, the influence of pH was studied on adsorption and subsequent hydrogenation of nitrite in water between pH 5 and 9 over Pd/Al2O3 and Pt/Al2O3, using ATR-IR spectroscopy. On both catalysts, pH clearly influenced the surface coverage and reaction rates...... of intermediates. For Pt/Al2O3, lowering the pH induced the increasing surface coverage of key reaction intermediates like NOsteps1620cm−1 and “HNO”(ads)1540cm−1, as well as increased hydrogenation rates, explaining the higher TOF at lower pH as reported in the literature. For Pd/Al2O3, the effect of pH...

  4. EFFECTS OF PH ON AGGLOMERATION STATE OF Al2O3 – ZrO2 (ZTA NANOCOMPOSITE POWDERS SYNTHESIZED BY TARTARIC GEL METHOD

    Directory of Open Access Journals (Sweden)

    Mustafa Tuncer

    2012-07-01

    Full Text Available Alumina – 20 vol% zirconia (ZTA nanocomposites were synthesized by the tartaric acid sol-gel method. The precursors gelled from solutions at different pH were prepared and then calcined from 1000 to 1500°C. Surface area measurement (BET, X-ray diffraction (XRD, scanning electron microscopy (SEM and transmission electron microscopy (TEM were used to characterize the synthesized powders. Control of agglomeration state was carried out by changing the pH of the solution. Weakly agglomerated powders were obtained at pH=6, whereas the solution at pH=1 revealed hard agglomerated powders, (agglomeration degrees, N, were found to be 16425 at pH=1 and 102 at pH=6, respectively. The pH dependence of agglomeration was explained by the dissociation behavior of tartaric acid at various pH environments. XRD results showed that the powders have been fully tetragonal phase at 1000°C, while they exhibited tetragonal zirconia with minor monoclinic phase as well as a-Al2O3 at 1500°C. The presence of a-Al2O3 in the nanocrystalline composite contributes the wide range of temperature stability for t-ZrO2 up to 1500°C. TEM micrograph confirmed that alumina and zirconia were dispersed homogenously. Mechanical properties (hardness and indentation fracture toughness of sintered samples were also determined.

  5. Fe/Al bimetallic particles for the fast and highly efficient removal of Cr(VI) over a wide pH range: Performance and mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Fenglian, E-mail: fufenglian2006@163.com [School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006 (China); Environmental Engineering and Science Program, Department of Biomedical, Chemical and Environmental Engineering (DBCEE), University of Cincinnati, OH 45221-0012 (United States); Cheng, Zihang [School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006 (China); Dionysiou, Dionysios D., E-mail: dionysios.d.dionysiou@uc.edu [Environmental Engineering and Science Program, Department of Biomedical, Chemical and Environmental Engineering (DBCEE), University of Cincinnati, OH 45221-0012 (United States); Tang, Bing [School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006 (China)

    2015-11-15

    Highlights: • Bimetallic particles with different Fe/Al mass ratios were prepared. • High removal rate of Cr(VI) was achieved in acidic, neutral, and alkaline pH. • No total iron ions at pH 3.0–11.0 and nearly no Al{sup 3+} at pH 3.0–7.0 were released. • Galvanic cell effect and high specific surface area contributed to Cr(VI) removal. - Abstract: The iron/aluminum (Fe/Al) bimetallic particles with high efficiency for the removal of Cr(VI) were prepared. Fe/Al bimetallic particles were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), SEM mapping, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). SEM mapping showed that the core of bimetal was Al, and the planting Fe was deposited on the surface of Al. In acidic and neutral conditions, Fe/Al bimetal can completely remove Cr(VI) from wastewater in 20 min. Even at pH 11.0, the Cr(VI) removal efficiency achieved was 93.5%. Galvanic cell effect and high specific surface area are the main reasons for the enhanced removal of Cr(VI) by bimetallic particles. There were no iron ions released in solutions at pH values ranging from 3.0 to 11.0. The released Al{sup 3+} ions concentrations in acidic and neutral conditions were all less than 0.2 mg/L. The bimetal can be used 4 times without losing activity at initial pH 3.0. XPS indicated that the removed Cr(VI) was immobilized via the formation of Cr(III) hydroxide and Cr(III)–Fe(III) hydroxide/oxyhydroxide on the surface of Fe/Al bimetal. The Fe/Al bimetallic particles are promising for further testing for the rapid and effective removal of contaminants from water.

  6. Aluminium uptake and translocation in Al hyperaccumulator Rumex obtusifolius is affected by low-molecular-weight organic acids content and soil pH.

    Directory of Open Access Journals (Sweden)

    Stanislava Vondráčková

    Full Text Available High Al resistance of Rumex obtusifolius together with its ability to accumulate Al has never been studied in weakly acidic conditions (pH > 5.8 and is not sufficiently described in real soil conditions. The potential elucidation of the role of organic acids in plant can explain the Al tolerance mechanism.We established a pot experiment with R. obtusifolius planted in slightly acidic and alkaline soils. For the manipulation of Al availability, both soils were untreated and treated by lime and superphosphate. We determined mobile Al concentrations in soils and concentrations of Al and organic acids in organs.Al availability correlated positively to the extraction of organic acids (citric acid < oxalic acid in soils. Monovalent Al cations were the most abundant mobile Al forms with positive charge in soils. Liming and superphosphate application were ambiguous measures for changing Al mobility in soils. Elevated transport of total Al from belowground organs into leaves was recorded in both lime-treated soils and in superphosphate-treated alkaline soil as a result of sufficient amount of Ca available from soil solution as well as from superphosphate that can probably modify distribution of total Al in R. obtusifolius as a representative of "oxalate plants." The highest concentrations of Al and organic acids were recorded in the leaves, followed by the stem and belowground organ infusions.In alkaline soil, R. obtusifolius is an Al-hyperaccumulator with the highest concentrations of oxalate in leaves, of malate in stems, and of citrate in belowground organs. These organic acids form strong complexes with Al that can play a key role in internal Al tolerance but the used methods did not allow us to distinguish the proportion of total Al-organic complexes to the free organic acids.

  7. Ensayo para el cultivo del camarón marino litopenaeus vannamei Pérez-Farfante y Kensley, 1997, a baja salinidad en la estación del Mariel

    OpenAIRE

    Cabrera Machado, J.E.; Jaime Ceballos, B.; Galindo López, J.

    2010-01-01

    Con el objetivo de evaluar el cultivo del camarón marino Litopenaeus vannamei a baja salinidad, se ensayaron diferentes modificaciones del agua de pozo de una localidad cercana al río Mosquito (Mariel, La Habana, Cuba), previo análisis de su composición iónica. Se desarrolló un diseño completamente aleatorizado a escala de laboratorio, durante 14 días, utilizando postlarvas (PL20). Al agua se le realizaron las siguientes modificaciones: I) agua de pozo + sal bruta + sulfato de mag...

  8. Processing and Mechanical Properties of NiAl-Based In-Situ Composites. Ph.D. Thesis Final Report

    Science.gov (United States)

    Johnson, David Ray

    1994-01-01

    In-situ composites based on the NiAl-Cr eutectic system were successfully produced by containerless processing and evaluated. The NiAl-Cr alloys had a fibrous microstructure while the NiAl-(Cr,Mo) alloys containing 1 at. percent or more molybdenum exhibited a lamellar structure. The NiAl-28Cr-6Mo eutectic displays promising high temperature strength while still maintaining a reasonable room temperature fracture toughness when compared to other NiAl-based materials. The Laves phase NiAlTa was used to strengthen NiAl and very promising creep strengths were found for the directionally solidified NiAl-NiAlTa eutectic. The eutectic composition was found to be near NiAl-15.5Ta (at. percent) and well aligned microstructures were produced at this composition. An off-eutectic composition of NiAl-14.5Ta was also processed, consisting of NiAl dendrites surrounded by aligned eutectic regions. The room temperature toughness of these two phase alloys was similar to that of polycrystalline NiAl even with the presence of the brittle Laves phase NiAlTa. Polyphase in-situ composites were generated by directional solidification of ternary eutectics. The systems investigated were the Ni-Al-Ta-X (X=Cr, Mo, or V) alloys. Ternary eutectics were found in each of these systems and both the eutectic composition and temperature were determined. Of these ternary eutectics, the one in the NiAl-Ta-Cr system was found to be the most promising. The fracture toughness of the NiAl-(Cr,Al)NiTa-Cr eutectic was intermediate between those of the NiAl-NiAlTa eutectic and the NiAl-Cr eutectic. The creep strength of this ternary eutectic was similar to or greater than that of the NiAl-Cr eutectic.

  9. Effect of coexisting Al(III) ions on Pb(II) sorption on biochars: Role of pH buffer and competition.

    Science.gov (United States)

    Yang, Yuxi; Zhang, Weihua; Qiu, Hao; Tsang, Daniel C W; Morel, Jean-Louis; Qiu, Rongliang

    2016-10-01

    Biochar is being widely considered as a promising amendment agent for immobilizing heavy metals in contaminated acidic soils, where plenty of soluble Al(III) ions exist. In view of uncertain significance of the effects of coexisting Al(III) on Pb(II) sorption by biochars, this study used kenaf core biochar (KB550; high carbon, low ash) and sewage sludge biochar (SB550; low carbon, high ash) pyrolyzed at 550 °C to elucidate the influence of coexisting Al(III) species and biochars' mineral components on Pb(II) immobilization conducted in aqueous solution with initial pHs of 3.0-4.5. Results showed that Al(III) reduced Pb(II) sorption on KB550 primarily via pH buffering against biochar alkalinity, thus inhibiting lead carbonate formation. In contrast, the reduction on SB550 mainly resulted from direct competition for sorption sites, especially on Fe-rich phengite 2M1 and metakaolinite. Because of Pb-P precipitation and Pb-K interlayer exchange, the residual Pb(II) adsorption capacity resistant to coexisting Al(III) was 3-5 times higher on SB550 than on KB550. The Pb-K interlayer exchange was enhanced by lower pH and coexisting Al(III), while Pb-P precipitation was the dominant Pb(II) sorption mechanism on SB550 resistant to Al(III) buffering and competition at higher pH. Application of these two biochars as amendments confirmed that the mineral-rich SB550 was more suitable for Pb(II) immobilization in acidic soils with high levels of extractable Al(III). PMID:27454898

  10. Nitrato modula os teores de cloreto e compostos nitrogenados em plantas de milho submetidas à salinidade

    Directory of Open Access Journals (Sweden)

    Alexcyane Rodrigues Feijão

    2013-03-01

    Full Text Available O objetivo deste trabalho foi estudar o efeito do nitrato (NO3- no crescimento e no acúmulo de solutos inorgânicos e orgânicos em plantas de milho submetidas à salinidade. O delineamento experimental foi o inteiramente casualizado, com cinco repetições, sob esquema fatorial 2×4, constando de oito tratamentos: dois níveis de salinidade (NaCl a 0 e 75 mM e quatro concentrações de NO3- (0,5; 2,5; 5,0 e 7,5 mM em sistema hidropônico. A massa seca da parte aérea e das raízes foi reduzida pela salinidade, porém isso foi menos evidente quando as plantas foram submetidas a concentrações de NO3- abaixo de 2,5 mM. O melhor crescimento das plantas foi observado na concentração aproximada de NO3- a 5,0 mM. Os teores de Na+ e Cl- aumentaram com a salinidade em todos os órgãos estudados, havendo maior acúmulo desses íons nas raízes. De modo geral, os teores de K+ foram pouco afetados por esse estresse. Com o aumento da concentração de NO3- no meio, houve melhora na absorção desse íon, levando à redução da absorção de Cl- e ao acúmulo de prolina e N-aminossolúveis. O estresse nutricional é mais limitante ao crescimento das plantas de milho que o estresse salino, cujos efeitos prejudiciais são minimizados por uma nutrição de NO3- adequada.

  11. Effects of pH, surface finish and thermal treatment on the corrosion of AlFeNi aluminum alloy. Characterization of oxide layers

    Science.gov (United States)

    Nabhan, D.; Kapusta, B.; Billaud, P.; Colas, K.; Hamon, D.; Dacheux, N.

    2015-02-01

    The aluminum alloy AlFeNi used as fuel cladding for the Jules Horowitz Reactor (JHR) may undergo corrosion in the reactor environment. In order to qualify the corrosion behavior of the fuel elements of the JHR in accidental conditions, several specimens of AlFeNi have been corroded at 250 °C for different durations (9-34 days) in distilled water at various pH (4.9, 5.2 and 5.6) chosen to simulate that currently considered for the JHR. On all specimens, the only crystalline corrosion product formed is boehmite (AlOOH). The corrosion film is composed of three oxide layers which show through thickness chemical composition variations. The iron-nickel precipitates pre-existing in the metal matrix are present in the inner and intermediate oxide layers though oxidized. For long corrosion times, some of the iron and nickel particles are released in the water and some precipitation is observed at the surface of the oxide layer. The effect of surface finish (as received or polished) and thermal treatment (annealed and not annealed) on the oxide growth rate has also been investigated. For durations over 25 days, pH = 5.6 appears to be more favorable than pH = 5.2 and 4.9 in terms of oxide thickness and weight gain limitation. This effect of pH is however reduced on unpolished specimens. The effect of surface finish on the corrosion behavior as measured by optical microscopy appears to be strong, especially for pH = 4.9 where polished samples exhibited an accelerated evolution of the oxide thickness and of the mass gain. This could be due to the combined effect of a strong acid solution (pH = 4.9) and of the local microstructural changes formed at the interface through polishing. The effect of thermal treatment on the behavior of unpolished AlFeNi specimens during corrosion tests in the conditions investigated was found to be small. In this study, microstructural and chemical analyses were performed on the corroded specimens in order to get a better understanding of the

  12. Effects of pH, surface finish and thermal treatment on the corrosion of AlFeNi aluminum alloy. Characterization of oxide layers

    Energy Technology Data Exchange (ETDEWEB)

    Nabhan, D., E-mail: diana.nabhan@cea.fr [Département des matériaux pour le nucléaire, CEA Saclay, 91191 Gif sur Yvette (France); Kapusta, B.; Billaud, P.; Colas, K.; Hamon, D. [Département des matériaux pour le nucléaire, CEA Saclay, 91191 Gif sur Yvette (France); Dacheux, N. [ICSM, UMR 5257 CNRS/CEA/UM2/ENSCM, Site de Marcoule, Bât 426, BP 17171, 30207 Bagnols/Cèze (France)

    2015-02-15

    The aluminum alloy AlFeNi used as fuel cladding for the Jules Horowitz Reactor (JHR) may undergo corrosion in the reactor environment. In order to qualify the corrosion behavior of the fuel elements of the JHR in accidental conditions, several specimens of AlFeNi have been corroded at 250 °C for different durations (9–34 days) in distilled water at various pH (4.9, 5.2 and 5.6) chosen to simulate that currently considered for the JHR. On all specimens, the only crystalline corrosion product formed is boehmite (AlOOH). The corrosion film is composed of three oxide layers which show through thickness chemical composition variations. The iron–nickel precipitates pre-existing in the metal matrix are present in the inner and intermediate oxide layers though oxidized. For long corrosion times, some of the iron and nickel particles are released in the water and some precipitation is observed at the surface of the oxide layer. The effect of surface finish (as received or polished) and thermal treatment (annealed and not annealed) on the oxide growth rate has also been investigated. For durations over 25 days, pH = 5.6 appears to be more favorable than pH = 5.2 and 4.9 in terms of oxide thickness and weight gain limitation. This effect of pH is however reduced on unpolished specimens. The effect of surface finish on the corrosion behavior as measured by optical microscopy appears to be strong, especially for pH = 4.9 where polished samples exhibited an accelerated evolution of the oxide thickness and of the mass gain. This could be due to the combined effect of a strong acid solution (pH = 4.9) and of the local microstructural changes formed at the interface through polishing. The effect of thermal treatment on the behavior of unpolished AlFeNi specimens during corrosion tests in the conditions investigated was found to be small. In this study, microstructural and chemical analyses were performed on the corroded specimens in order to get a better understanding of the

  13. Efecto de la salinidad en la eï¬�ciencia en el uso del agua y la producción de materia seca en guayabo

    OpenAIRE

    Casierra, Fánor Casierra Posada; Dotor, Ing. Agr. Ph.D.; Bernardo A.; González M, Ing. Agr.; Leonardo A.

    2006-01-01

    En plantas de guayaba (Psidium guajava L. cvs. RS 980 y Cimpa 00916) se evaluó el efecto de la salinidad sobre el crecimiento, la producción de materia seca y la eï¬�cacia agronómica en el uso del agua. Las plantas se obtuvieron a partir de semilla, crecieron en un invernadero en materas (tres litros) y se expusieron a condiciones no salinas (ECe: 1.2 dS.m-1) o salinas mediante la adición de 20; 40; 60 y 80 mM de NaCl con base en suelo seco al aire (ECe:3.0, 5.4, 7.9 y 10.5 dS.m-1 respectivam...

  14. Nature and reactivity of layered double hydroxides formed by coprecipitating Mg, Al and As(V): Effect of arsenic concentration, pH, and aging.

    Science.gov (United States)

    Sommella, Alessia; Caporale, Antonio G; Denecke, Melissa A; Mangold, Stefan; Pigna, Massimo; Santoro, Anna; Terzano, Roberto; Violante, Antonio

    2015-12-30

    Arsenic (As) co-precipitation is one of the major processes controlling As solubility in soils and waters. When As is co-precipitated with Al and Mg, the possible formation of layered double hydroxides (LDHs) and other nanocomposites can stabilize As in their structures thus making this toxic element less available. We investigated the nature and reactivity of Mg-Al-arsenate [As(V)] co-precipitated LDHs formed in solution affected by As concentration, pH, and aging. At the beginning of the co-precipitation process, poorly crystalline LDH and non-crystalline Al(Mg)-oxides form. Prolonged aging of the samples promotes crystallization of LDHs, evidenced by an increase in As K XANES intensities and XRD peak intensities. During aging Al- and/or Mg-oxides are likely transformed by dissolution/re-precipitation processes into more crystalline but still defective LDHs. Surface area, chemical composition, reactivity of the precipitates, and anion exchange properties of As(V) in the co-precipitates are influenced by pH, aging, and As concentration. This study demonstrates that (i) As(V) retards or inhibits the formation and transformation of LDHs and (ii) more As(V) is removed from solution if co-precipitated with Mg and Al than by sorption onto well crystallized LDHs. PMID:26241870

  15. The Effect of Saccharomyces Strains and Fermentation Condition on the pH, Foam Property and CO2 Concentration of Non-alcoholic Beer (Ma-al-shaeer

    Directory of Open Access Journals (Sweden)

    S. Sohrabvandi

    2014-12-01

    Full Text Available This study aims to determine the effect of fermentation condition and Saccharomyces strains on the pH, foam property and CO2 concentration of non-alcoholic beer (Ma-al-shaeer. For this, the beer samples were inoculated with four different species of Saccharomyces (Saccharomyces rouxii 70531, S. rouxii 70535, S. ludwigii 3447 and S. cerevisiae 70424 and fermented for 48h in both aerobic and periodic aeration at three different temperatures. Then their pH, CO2 concentration and foam property were analyzed in 12h intervals during 48h fermentation. The results shows that the treatments with 4×107 CFU.ml-1 and periodic aeration at 24˚C showed the greatest decrease in pH, and the treatments with 107 CFU.ml-1 and aerobic-periodic aeration at 4˚C showed the lowest decrease in pH. The highest and lowest amounts of CO2 and foam property were obtained in the treatments with 4×107 CFU.ml-1 inoculation, aerobic condition, and the treatments with 107 CFU.ml-1, periodic aeration, respectively. These results further demonstrated that the highest drop in pH, and the highest ability of producing CO2 and foam were for S. cerevisiae 70424, and the lowest belonged to S. rouxii 70531. The overall outcome of the study points to the fact that physico-chemical properties of Ma-al-shaeer is important from the consumers' point of view. Therefore, S. cerevisiae with 4×107 CFU.ml-1 inoculation and aerobic condition at 4˚C has promising potential for producing Ma-al-shaeer with good physicochemical properties.

  16. Processing, physical metallurgy and creep of NiAl + Ta and NiAl + Nb alloys. Ph.D. Thesis. Final Contractor Report

    Science.gov (United States)

    Pathare, Viren M.

    1988-01-01

    Powder processed NiAl + Ta alloys containing 1, 2, and 4.5 at percent tantalum and NiAl + Nb alloys containing 1 and 2 at percent niobium were developed for improved creep properties. In addition, a cast alloy with 5 at percent tantalum was also studied. Hot extrusion parameters for processing alloys with 1 and 2 at percent of tantalum or niobium were designed. The NiAl + 4.5 at percent Ta alloy could be vacuum hot pressed successfully, even though it could not be extruded. All the phases in the multiphase alloys were identified and the phase transformations studied. The Ni2AlTa in NiAl + 4.5 at percent Ta alloy transforms into a liquid phase above 1700 K. Solutionizing and annealing below this temperature gives rise to a uniform distribution of fine second phase precipitates. Compressive creep properties were evaluated at 1300 K using constant load and constant velocity tests. In the higher strain rate region single phase NiAl + 1 at percent Ta and NiAl + 1 at percent Nb alloys exhibit a stress exponent of 5 characteristic of climb controlled dislocation creep. In slower strain rate regime diffusional creep becomes important. The two phase alloys containing 2 to 5 at percent Ta and 2 at percent Nb show considerable improvement over binary NiAl and single phase alloys. Loose dislocation networks and tangles stabilized by the precipitates were found in the as crept microstructure. The cast alloy which has larger grains and a distribution of fine precipitates shows the maximum improvement over binary NiAl.

  17. RÉGIMEN HÍDRICO Y AJUSTE OSMÓTICO EN VARIEDADES CUBANAS DE TRIGO (Triticum aestivum Y T. durum CULTIVADAS EN CONDICIONES DE SALINIDAD

    Directory of Open Access Journals (Sweden)

    Leandris Argentel

    2013-01-01

    Full Text Available Los potenciales hídrico y osmótico y el ajuste osmótico en 12 variedades cubanas de trigo pertenecientes a las especies Triticum aestivum y Triticum durum cultivadas en condiciones de salinidad fueron evaluados, siguiendo las metodologías para tales fines. Las plantas se establecieron en un invernadero en condiciones de hidroponía a un nivel de salinidad de 8 dS.m -1 , como control se montó un tratamiento con una conductividad eléctrica de 0,36 dS.m -1 . Las evaluaciones se realizaron a los 25 días posteriores a la germinación. Como resultado se obtuvo una significativa disminución de los valores del potencial hídrico en la mayoría de las variedades en todos los órganos medidos y se observó una significativa disminución de sus valores desde las raíces hasta las hojas para asegurar el gradiente hídrico. Las variedades que no disminuyeron significativamente su potencial hídrico mostraron comportamiento similar en los tres órganos evaluados aunque el gradiente de potenciales se mantuvo. El potencial osmótico disminuyó significativamente en todas las variedades y sus valores fueron inferiores a -0,6 MPa. Todas las variedades realizaron el ajuste osmótico, siendo el valor más significativo AO= 0,3 MPa en las variedades INIFAT RM-36, INIFAT RM-32, INIFAT RM-37. Se observó variabilidad en la respuesta al estrés salino entre variedades y especies para las tres variables evaluadas.

  18. Study of the effect of PH, surface finish and thermal treatment on the corrosion of AlFeNi aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Nabhan, Diana [Comissariat a l' Energie Atomique, Paris (France)

    2013-07-01

    The Jules Horowitz Reactor (JHR) is a research reactor under construction at the CEA Cadarache research center, France. It is scheduled to start operating by 2020. The fuel elements of this reactor core consist of eight concentric rows of cylindrical plates, each row being composed of three thin aluminum coated plates. Cooling water circulates between these plates through very thin gaps smaller than 2 mm. The aluminum alloy used to coat the fuel plates is an alloy called AlFeNi, which contains 1% wt. Fe, 1% wt. Ni and 1% wt. Mg. In the reactor environment, this alloy may undergo corrosion. The oxide layer formed on the AlFeNi alloy is composed of two different types of oxides: an inner oxide layer formed by a diffusion mechanism and an outer oxide layer formed by re-precipitation. As a consequence, formation of an oxide scale on the aluminum coating could reduce the gap between the cladding plates, thus allowing less water to circulate. This could in turn lead to local heating of the fuel cladding. In addition, the metal consumption and the softening of the metal at high temperatures can lead to a decrease of the mechanical strength of the cladding. In order to qualify the fuel elements of the JHR, several specimens of AlFeNi, representative of the future cladding, were corroded at 250 .deg. C for different durations (9 to 34 days) in distilled water of different pH: 4.9; 5.2 and 5.6. These pH values have been chosen to simulate the ones currently predicted for the JHR. The effect of surface finish (polished and not polished) and thermal treatment (annealed and not annealed) on the oxide growth rate was also investigated. For long tests over 30 days, the pH 5,6 appears to be more favorable than the pH 5,2 and 4,9 to limit the oxide thickness, but this pH effect is reduced on unpolished samples. In one hand, the effect of surface finish on the corrosion behavior as measured by optical microscopy appears to be strong. On the other hand, the effect of thermal

  19. Efectos de la salinidad y el herbicida glifosato sobre la especie invasora Baccharis halimifolia

    OpenAIRE

    Ruiz de Galarreta, Marina

    2015-01-01

    CASTELLANO. La introducción de especies exóticas invasoras es una de las causas más importantes de pérdida de biodiversidad. Baccharis halimifolia es una de las 20 especies exóticas invasoras mas perjudiciales en España e invade gran parte de la marisma de Urdaibai. En dicha marisma se aplicaron tratamientos de control mediante la corta y aplicación de herbicida (glifosato) tras los cuales se observó un variable porcentaje de rebrote en función de la salinidad edáfica. Se realizó un experim...

  20. Impacto económico de la salinidad de los suelos en la agricultura de Bardenas I

    OpenAIRE

    Zekri, Slim; Albisu Aguado, Luis Miguel; Aragüés Lafarga, Ramón; Herrero Isern, Juan

    1990-01-01

    La acumulación de sales en los suelos es uno de los problemas que afecta a los regadíos en Bardenas. El objetivo de este trabajo es analizar las pérdidas económicas actuales así como los futuros beneficios que resultarían con la recuperación de estos suelos salinos. Mediante la programación lineal multiobjetivo se intenta presentar la situación actual con los niveles de salinidad existentes. Utilizando la misma metodología se simula una situación futura suponiendo que no existiera salinidad. ...

  1. Investigation of Strain Aging in the Ordered Intermetallic Compound beta-NiAl. Ph.D. Thesis Final Contractor Report

    Science.gov (United States)

    Weaver, Mark Lovell

    1995-01-01

    The phenomenon of strain aging has been investigated in polycrystalline and single crystal NiAl alloys at temperatures between 300 and 1200 K. Static strain aging studies revealed that after annealing at 1100 K for 7200 s (i.e., 2h) followed by furnace cooling, high purity, nitrogen-doped and titanium-doped polycrystalline alloys exhibited continuous yielding, while conventional-purity and carbon-doped alloys exhibited distinct yield points and Luders strains. Prestraining by hydrostatic pressurization removed the yield points, but they could be reintroduced by further annealing treatments. Yield points could be reintroduced more rapidly if the specimens were prestrained uniaxially rather than hydrostatically, owing to the arrangement of dislocations into cell structures during uniaxial deformation. The time dependence of the strain aging events followed at t(exp 2/3) relationship suggesting that the yield points observed in polycrystalline NiAl were the result of the pinning of mobile dislocations by interstitials, specifically carbon. Between 700 and 800 K, yield stress plateaus, yield stress transients upon a ten-fold increase in strain rate, work hardening peaks, and dips in the strain rate sensitivity (SRS) have been observed in conventional-purity and carbon-doped polycrystals. In single crystals, similar behavior was observed; in conventional-purity single crystals, however, the strain rate sensitivity became negative resulting in serrated yielding, whereas, the strain rate sensitivity stayed positive in high purity and in molybdenum-doped NiAl. These observations are indicative of dynamic strain aging (DSA) and are discussed in terms of conventional strain aging theories. The impact of these phenomena on the composition-structure-property relations are discerned. Finally, a good correlation has been demonstrated between the properties of NiAl alloys and a recently developed model for strain aging in metals and alloys developed by Reed-Hill et al.

  2. POLIAMINAS COMO MARCADORES BIOQUÍMICOS DE SALINIDADE EM CALOS DE Eucalyptus urograndis

    Directory of Open Access Journals (Sweden)

    Giuseppina Pace Pereira Lima

    2002-11-01

    Full Text Available Marcadores bioquímicos têm sido usados na análise de plantas submetidas a vários tipos de estresse, entre eles a salinidade. Este trabalho teve como objetivo analisar o estresse salino em calos de Eucalyptus urograndis em relação ao conteúdo de poliaminas. Explantes (hipocótilos obtidos de sementes foram inoculados em meio indutivo de calos e foram submetidos a diferentes níveis de NaCl e analisados aos 10, 20 e 30 dias de inoculação. As poliaminas livres foram extraídas, isoladas e quantificadas usando TLC (Cromatografia de Camada Delgada. O conteúdo de putrescina foi maior, enquanto que o conteúdo de espermidina apresentou decréscimo, em calos submetidos a condições salinas. Os resultados mostram que o acúmulo de putrescina está relacionado com a exposição a NaCl em calos de Eucalyptus urograndis. A diminuição do conteúdo de espermina pode ser usada como marcador bioquímico de calos de Eucalyptus sujeitos à salinidade.

  3. Efecto de la calidad de agua del acuífero Valle de Guadalupe en la salinidad de suelos agrícolas Water quality effect on the Valle de Guadalupe aquifer in the agricultural soils salinity

    OpenAIRE

    Jorge Arturo Salgado Tránsito; Oscar Palacios Vélez; Arturo Galvis Spínola; Francisco Gavi Reyes; Enrique Mejía Sáenz

    2012-01-01

    Para determinar el efecto de la calidad del agua en el Acuífero del Valle de Guadalupe, Baja California, México, en la salinidad de los suelos agrícolas se midió el pH, conductividad eléctrica, sólidos disueltos totales y la concentración de los principales iones en las aguas de 66 pozos, de un total de 754 que se encontraban en operación en el acuífero durante 2009 .Y se analizó en el extracto de pasta de saturación de muestras de suelo el pH, conductividad eléctrica, carbonato, bicarbonato,...

  4. Comment on "Quantum key distribution with 1.25 Gbps clock synchronization" by J.C. Bienfang et al., quant-ph/0405097

    CERN Document Server

    Hughes, R J; Hughes, Richard J.; Nordholt, Jane E.

    2004-01-01

    We analyze the significance for quantum key distribution (QKD) of free-space quantum communications results reported in a recent paper (J. C. Bienfang et al., quant-ph/0405097, hereafter referred to as "Bienfang et al."), who contrast the quantum communications rate of their partial QKD implementation (which does not produce cryptographically useful shared, secret keys) over a short transmission distance, with the secret bit rates of previous full QKD implementations over much longer distances. We show that when a cryptographically relevant comparison with previous results is made, the system described by Bienfang et al. would offer no advantages for QKD, contrary to assertions in their paper and in spite of its high clock rate. Further, we show that the claim made by Bienfang et al. that "high transmission rates serve ... to extend the distance over which a QKD system can operate" is incorrect. Our analysis illustrates an important aspect of QKD that is too often overlooked in experiments: the sifted bit rat...

  5. AJUSTAMENTO OSMÓTICO EM MUDAS DE JATOBÁ SUBMETIDAS À SALINIDADE EM MEIO HIDROPÔNICO

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    Hugo Henrique Costa do Nascimento

    2015-08-01

    Full Text Available RESUMOEm ambientes naturais, a salinidade representa grande empecilho ao desenvolvimento dos vegetais. Visando à melhor compreensão dos efeitos que ela provoca na fisiologia de espécies arbóreas nativas, este trabalho objetivou avaliar o comportamento fisiológico de mudas de jatobá (Hymenaea courbaril L. submetidas à salinidade em meio hidropônico. Portanto, um experimento foi realizado em casa de vegetação do Laboratório de Fisiologia Vegetal da Universidade Federal Rural de Pernambuco, adotando-se um delineamento experimental inteiramente casualizado em arranjo fatorial 3 x 2, composto por três tratamentos salinos: Controle (solução nutritiva sem adição de NaCl, Estresse moderado (adição de 50 mM de NaCl e Estresse severo (adição de 100 mM de NaCl e duas épocas de avaliação (1ª época: constatação do fechamento estomático; e 2ª época: após a verificação da abertura estomática das plantas submetidas à salinidade, com 20 repetições em cada tratamento. Durante o estudo, foram verificadas as trocas gasosas, as relações hídricas, os teores de pigmentos fotossintéticos e o acúmulo de solutos orgânicos e inorgânicos. Ao final do experimento, observou-se que as mudas de jatobá se ajustaram osmoticamente após a indução do estresse severo, uma vez que acumularam solutos orgânicos que promoveram a elevação da turgescência foliar, resultando na estabilização das trocas gasosas, mesmo após a submissão ao estresse severo.

  6. DESENVOLVIMENTO INICIAL DA GRAVIOLEIRA SOB FONTES E NÍVEIS DE SALINIDADE DA ÁGUA

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    CAVALCANTE LOURIVAL FERREIRA

    2001-01-01

    Full Text Available No período de fevereiro a julho de 1999, estudaram-se os efeitos de fontes salinas através da irrigação com água de barragem, rica em cloreto de sódio e em cloreto de magnésio, com níveis de condutividade elétrica de 0,5; 1,0; 2,0; 3,0; 6,0 e 9,0 dSm-1 sobre o crescimento inicial da gravioleira, Annona muricata L., cultivar Morada. Os resultados nos primeiros 150 dias, independentemente das fontes, indicam que área foliar e sua fitomassa cresceram com o aumento da salinidade das águas de 0,5 para 2,0 e até 3,0 dSm-1. No mesmo período, o índice de salinidade do substrato foi elevado para até fortemente salino, revelando que a gravioleira comportou-se como planta moderadamente tolerante aos sais durante o crescimento inicial. Apesar de a água rica em cloreto de magnésio ser a fonte que menos elevou a condutividade elétrica do substrato, foi a que mais contribuiu para a redução das variáveis estudadas, indicando que as plantas foram mais sensíveis a sua toxidade em relação à água de barragem e rica em cloreto de sódio.

  7. Fotossíntese e acúmulo de solutos em feijoeiro caupi submetido à salinidade

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    Rogéria Pereira Souza

    2011-06-01

    Full Text Available O objetivo deste trabalho foi determinar as respostas fotossintéticas e a acumulação de carboidratos, íons salinos e prolina em feijoeiro caupi (Vigna unguiculata submetido à salinidade. As plantas foram submetidas à quatro tratamentos, dos 28 aos 35 dias de idade: 0, 50, 100 e 200 mmol L-1 de NaCl. Avaliaramse as trocas gasosas, a emissão de fluorescência pela clorofila a, o potencial hídrico foliar, e as concentrações de carboidratos, Na+, Cl- e prolina nas folhas. Os tratamentos não tiveram efeito sobre a eficiência quântica potencial do fotossistema II, mas causaram leve diminuição na eficiência quântica efetiva e maior dissipação do excesso de energia de excitação por processos não fotoquímicos. As concentrações foliares de amido diminuíram, e as de sacarose e prolina aumentaram nas maiores concentrações de NaCl. Ocorreu exclusão do Na+ e acúmulo do Cl- nas folhas, e as relações hídricas das folhas foram pouco afetadas, exceto no tratamento mais severo. O acúmulo de Cl- esteve envolvido na redução da assimilação de CO2, decorrente da queda na condutância estomática e na eficiência de carboxilação da Rubisco. O feijoeiro caupi apresenta características fisiológicas que favorecem a manutenção da atividade fotossintética sob curta exposição à salinidade.

  8. Evaluación de la tolerancia a la salinidad en estadios tempranos y finales del desarrollo en Triticales (X Triticum secale

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    L. Argentel

    2010-01-01

    salino con una conductivid eléctrica (CE de 10 dS.m-1 y un tratamiento control con CE=0.02 dS.m-1. En el primer ensayo se evaluaron las variables: absorción de agua, altura de las plántulas, longitud de la raíz y acumulación de biomasas fresca y seca. La evaluación en las etapas finales se realizó mediante el estudio de los componentes del rendimiento. Todos los datos se expresaron en valores relativos al control. Mediante un análisis de conglomerados jerárquico se realizó una caracterización en cuanto a su grado de tolerancia relativa para ambos estadios. Como resultado se obtuvo una amplia variabilidad en la respuesta al estrés en las dos fenofases. Solo se observó tolerancia en una línea (ITSN-14; sin embargo, los índices fueron altos en relación con los informes encontrados en esta especie, por lo que se recomienda evaluarlas mediante el uso de otros indicadores fisiológicos y bioquímicos más precisos de tolerancia a la salinidad

  9. Ein abgründiges Thema – Inzest als historisches Phänomen An Abysmal Issue—Incest as Historical Phenomenon

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    Pascal Eitler

    2004-11-01

    Full Text Available Der vorliegende Sammelband bietet einen vielschichtigen, aber ergänzungsbedürftigen Überblick zur Geschichte der Inzestproblematik vom 13. bis zum 20. Jahrhundert. Er beinhaltet interdisziplinäre Studien sowohl zu dem sich historisch wandelnden Inzestbegriff als auch zu der sich verändernden Umgangsweise mit dem Phänomen Inzest. Im Zentrum des Interesses stehen dabei die unterschiedlichen Verwandtschaftsvorstellungen und Sexualitätsnormen, die im Rahmen der Inzestthematik verhandelt werden.The collection at hand offers a multilayered historical overview, though in need of some addition, of the incest problematic from the Thirteenth to the Twentieth Century. It contains interdisciplinary studies on the historically changing definition of incest as well as the changing ways of approaching the phenomenon of incest itself. Differing perceptions of familial relations and sexual norms, negotiated within the framework of the incest thematic, form the core concern of the study.

  10. Effective surface passivation of AlGaN/GaN heterostructures by using PH{sub 3} plasma treatment and HfO{sub 2} dielectric

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Chunfu; Hao, Yue; Feng, Qian [Wide Bandgap Semiconductor Technology Disciplines State Key Laboratory, School of Microelectronics, Xidian University, 710071 Xi' an (China)

    2012-03-15

    Different surface passivation methods of AlGaN/GaN heterostructures were investigated in this work. C-V measurement shows that very high trap density (D{sub it}) of 1.51 x 10{sup 13}cm{sup -2}eV{sup -1} exists at the AlGaN/GaN surface, which has activation energy of 0.765 eV. The surface treatment by using O{sub 2} plasma treatment and HfO{sub 2} dielectric can efficiently lower D{sub it} to 3.57 x 10{sup 12}cm{sup -2}eV{sup -1} and 1.06 x 10{sup 12}cm{sup -2}eV{sup -1}, repectively. To reduce these deep trap states further, a more effective passivation method is presented here. By using the PH{sub 3} plasma treatment before the HfO{sub 2} deposition, D{sub it} was further greatly reduced and reached a very low value of 1.37 x 10{sup 11}cm{sup -2}eV{sup -1}. (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Efecto de la calidad de agua del acuífero Valle de Guadalupe en la salinidad de suelos agrícolas Water quality effect on the Valle de Guadalupe aquifer in the agricultural soils salinity

    Directory of Open Access Journals (Sweden)

    Jorge Arturo Salgado Tránsito

    2012-02-01

    Full Text Available Para determinar el efecto de la calidad del agua en el Acuífero del Valle de Guadalupe, Baja California, México, en la salinidad de los suelos agrícolas se midió el pH, conductividad eléctrica, sólidos disueltos totales y la concentración de los principales iones en las aguas de 66 pozos, de un total de 754 que se encontraban en operación en el acuífero durante 2009 .Y se analizó en el extracto de pasta de saturación de muestras de suelo el pH, conductividad eléctrica, carbonato, bicarbonato, cloruro, sulfato, boro, fósforo, nitrato, calcio, magnesio, sodio, potasio, amonio. El 74% de los suelos estudiados presenta una cantidad superior a 15 mg kg-¹ de nitratos, y por tratarse de suelos arenosos se atribuyen problemas de contaminación a las aplicaciones de fertilizantes nitrogenados. La salinidad del agua está presente en todo acuífero del Valle de Guadalupe (clasificada como C3 y C4 en 85.9%, pero la salinidad del suelo (pHpromedio= 7.6 no se presenta en el total de la superficie del valle; por lo tanto el agua del acuífero no es la única causante de dicho problema, el manejo del agua para riego y la aplicación de fertilizantes deben ser estudiados para cuantificar su contribución a la salinidad del suelo.In order to determine the effect of water quality in the Valle de Guadalupe aquifer, Baja California, Mexico, in the agricultural soils salinity the pH, electrical conductivity, total dissolved solids and the concentration of major ions in water of 66 wells were measured, from 754 that were in operation in the aquifer during 2009. The pH, electrical conductivity, carbonate, bicarbonate, chloride, sulfate, boron, phosphorus, nitrate, calcium, magnesium, sodium, potassium, and ammonium were analyzed in the paste extract saturation of the soil samples. 74% of the soils studied presented an amount higher than 15 mg kg-¹ of nitrate, and due to sandy soils, contamination problems are attributed to nitrogen fertilizer

  12. Evaluación general de la salinidad y modelación de los riesgos de salinización en suelos del Valle del Cauca: uso práctico del modelo PLA para evaluar el riesgo de salinización en tierras bajo riego en la parte plana del Valle del Cauca (Colombia)

    OpenAIRE

    Ramírez Alzate, Jorge Armando

    2011-01-01

    La investigación se desarrolló basándose en evidencias y estudios previos de salinidad. Se muestrearon 100 suelos y aguas de riego utilizados en caña de azúcar entre los municipios de Zarzal y El Cerrito. Los suelos a cuatro profundidades (0-20, 20-40, 40-60, 60-80 cm.) y las aguas de riego de diferentes fuentes. Tanto en las aguas como en los extractos de saturación se determinó pH, conductividad eléctrica (C.E.), calcio (Ca2+), magnesio (Mg2+), potasio (K+), sodio (Na+), cloruros (Cl-), sul...

  13. Influencia de la salinidad edáfica sobre la calidad del aceite de oliva cv. Arbequina

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    Aragüés, R.

    2005-03-01

    Full Text Available This work analyzes the effect of soil salinity on olive oil quality. The chemical composition of oils extracted from young ‘Arbequina' olives subject in the field to three soil salinity levels (low-L, medium-M and high-H was determined throughout a period of three years. A total of 30 parameters were analyzed (moisture, oil content, acidity, peroxides, ultraviolet absorbances, poliphenols, aliphatic alcohols, sterols, waxes, and fatty acid composition. Soil salinity was measured on fourteen different dates with an electromagnetic sensor. Overall, salinity increased oil content (+15 % in H with respect to L and decreased aliphatic alcohols (-29 % and palmitoleic acid (-32 % (values significant at P0,05. In summary, olive oil quality was practically independent of soil salinity and, according to the prevailing legislation, all the oils were classified as “extra virgin”.Este trabajo analiza el efecto de la salinidad edáfica sobre la calidad del aceite de oliva. Durante tres campañas se determinó la composición química de aceites provenientes de olivos jóvenes ‘Arbequina' sujetos en campo a tres niveles de salinidad (baja-B, media-M y alta-A. En total se analizaron 30 parámetros (humedad, grasa, acidez, peróxidos, lecturas en el ultravioleta, polifenoles, alcoholes alifáticos, esteroles, ceras y composición de ácidos grasos. La salinidad edáfica se midió en catorce fechas con un sensor electromagnético. La salinidad produjo un aumento del porcentaje de grasa (+15 % en A respecto a B, y un descenso de los alcoholes alifáticos (-29 % y del ácido palmitoleico (-32 % (valores significativos a P0,05. En conclusión, la calidad del aceite de oliva fue prácticamente independiente de la salinidad, clasificándose en todos los casos como “virgen extra” según la normativa vigente.

  14. Evaluación de la tolerancia a la salinidad en el estado juvenil de tres nuevas líneas de arroz (Oryza sativa L. utilizando marcadores morfoagronómicos

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    Elizabeth Cristo

    2001-01-01

    Full Text Available En el Laboratorio de Genética de la Estación Experimental del Arroz, se estudió el comportamiento de las nuevas líneas de arroz 8610, 8736, 8734, así como las variedades Pokkali y Amistad-82 (testigos tolerante y susceptible respectivamentea la salinidad a diferentes concentraciones salinas (0.4, 0.7, 1.0 % y un control con agua destilada. Se evaluaron el porcentaje de germinación, la altura de las plantas y longitud del sistema radical, mostrándose un comportamiento diferenciado en los genotipos bajo diferentes tenores salinos. Las líneas 8736 y 8734 mostraron mejor comportamiento en los tres indicadores analizados para este tipo de estrés, en comparación al testigo tolerante. Con el aumento de las concentraciones salinas, se afectaron los primeros estadios de crecimiento de las plantas.

  15. Besprechung: W. SEIBT-J. PREISER-KAPELLER (Hgg., Die Entstehung der kaukasischen Alphabete als kulturhistorisches Phänomen, Wien 2011

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    Nino DOBORJGINIDZE

    2014-01-01

    Full Text Available Normal 0 false false false EL X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Κανονικός πίνακας"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Besprechung:W. Seibt – J. Preiser-Kapeller (Hgg., Die Entstehung der kaukasischen Alphabete als kulturhistorisches Phänomen. Referate des Internationalen Symposions (Wien, 1.-4. Dezember 2005, Verlag der Österreichischen Akademie der Wissenschaften, Wien 2011 (=Österreichische Akademie der Wissenschaften. Phil.-hist. Kl. Denkschriften, 430. Band; Veröffentlichungen zur Byzanzforschung, Band 28. ISBN 978-3-7001-7088-4

  16. Efeito da salinidade da água de irrigação na produção da alface americana Effect of irrigation water salinity on american lettuce production

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    Eliezer Santurbano Gervásio

    2000-04-01

    Full Text Available Com o objetivo de se verificar o efeito de diferentes concentrações de sais da água de irrigação na produção da alface americana e sua acumulação no extrato saturado durante um ciclo de cultivo, instalou-se o presente experimento em casa de vegetação, no Departamento de Engenharia da Universidade Federal de Lavras, MG. Utilizou-se o delineamento inteiramente casualizado, com cinco repetições, sendo testados seis níveis de salinidade de água (condutividade elétrica de 0,18, 1,0, 1,5, 3,0, 4,5 e 6,0 dS m-1. Os resultados obtidos mostraram que o consumo de água pelas plantas, durante o ciclo de produção, diminuiu com níveis crescentes de salinidade da água de irrigação e que o aumento da salinidade proporcionou decréscimos em todas as variáveis vegetativas avaliadas. A máxima produção comercial da alface americana foi obtida quando a condutividade elétrica do extrato saturado atingiu o valor limite de 0,2 dS m-1. Para cada aumento unitário desta condutividade além do limite citado, houve uma redução de 17% na sua produção comercial.With the objective of verifying the effect of different concentrations of salts in the irrigation water on the production of the American lettuce, as well as its accumulation in the saturation extract during a cultivation cycle, one experiment was conducted under greenhouse conditions in the Department of Engineering of the Federal University of Lavras. The statistical design adapted was completely randomized, with 6 levels of water salinity (electric conductivity of 0.18, 1.0, 1.5, 3.0, 4.5 and 6.0 dS m-1 and 5 replications. The results obtained showed that the consumption of water for the plants during the production cycle decreased with increasing levels of salinity of irrigation water, and that the increase of the salinity caused a reduction in appraised vegetative variables. The maximum commercial production of the American lettuce was obtained when the electrical conductivity of

  17. Cultivos discontinuos alimentados con urea de la cianobacteria Phormidium sp. en función de la salinidad y edad del cultivo

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    Lorena del valle Jonte Gómez

    2013-12-01

    Full Text Available Título en ingles: Urea fed-batch cultures of the cyanobacterium  Phormidium sp. as a function of the salinity and age of cultures Título corto: Cultivos discontinuos alimentados de Phormidium sp.Resumen: Se  Se comparó la eficiencia de sistemas de cultivos discontinuos alimentados versus cultivos discontinuos convencionales, en cuanto a concentración de nitrógeno, adicionando 0,2 mM de urea cada tres días al final de la fase exponencial, durante 21 días. Se realizaron cultivos con un volumen de 1500 mL a 15 y 35 UPS de salinidad, enriquecidos con medio ALGAL 8mM NaNO3, a 238 mmol q m-2 s-1, aireación constante, fotoperiodo 12:12 horas y temperatura de 29 ±3ºC. Phormidium sp. posee la capacidad de hidrolizar la urea; mostrando una asimilación de 65±7,07% de la misma, con la mayor producción (p´<´0,05 de clorofila a, ficocianina y proteínas de 20,26±1,24; 203,47±12,83 y 707,87±28,47 µg mL-1en los cultivos alimentados. La producción de pigmentos vario en el tiempo, independientemente a la salinidad y sistema de cultivo, mientras que la producción de proteínas y carbohidratos totales fue directamente proporcional a la edad del cultivo, con valores máximos de 612,74±5,41 µg mL-1 y 8,96±0,08 mg mL-1 respectivamente a los 31 días. La síntesis de lípidos y EPS fueron influenciadas (p´<´0,05 por la salinidad, presentando los máximos de lípidos a 15 UPS con 12,22±2,91mg mL-1, y los EPS se incrementaron a 35 UPS con 2,00±0,26 y 2,03±0,15 mg mL-1. Estos resultados determinan que los cultivos de Phormidium sp. alimentados con urea y a salinidades de 15 y 35 UPS, representan una alternativa económica para la producción de clorofila a, ficocianina y proteínas, incrementándose un 31,04; 40,72 y 31,94 % respectivamente en comparación con cultivos no alimentados.Palabras clave: clorofila, ficocianina, proteínas, cianobacteria, urea.Abstract: Fed-batch system efficiency versus batch cultures was compared in relation

  18. DISTRIBUCIÓN VERTICAL DE TEMPERATURA Y SALINIDAD EN EL ÁREA COSTERA DE SANTA MARTA (COLOMBIA

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    FRANCISCO GARCÍA

    2012-01-01

    Full Text Available Fueron determinados los perfi les de temperatura, salinidad y densidad en el punto de descarga del emisario submarino de Santa Marta. Se encontraron tres masas de aguas. Los periodos de estratifi cación térmica coinciden con las dos épocas de lluvias en la región (entre abril y junio la primera y agosto y diciembre la segunda. El espesor de la termoclina puede alcanzar hasta 12 metros de espesor y gradientes térmicos de 0.67 °C/m.

  19. Avaliação de genótipos de caupi sob salinidade Assessment of cowpea genotypes under salinity

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    José P. Dantas

    2002-12-01

    Full Text Available Foram conduzidos ensaios em abrigo telado de vegetação com cobertura de telha de fibra de vidro com o objetivo de se avaliar a tolerância de 50 genótipos de caupi sob salinidade. Os tratamentos de salinidade aplicados no solo, em termos de condutividade elétrica do extrato de saturação (CE, foram: CE1 - 0,3, CE2 - 3,0, CE3 - 6,0, CE4 - 9,0 e CE5 - 12,0 dS m-1. Os genótipos foram classificados para tolerância à salinidade com base na redução percentual do peso de matéria seca da parte aérea. No tratamento CE2, 36 genótipos foram tolerantes (T, 12 moderadamente tolerantes (MT e 2 moderadamente sensíveis (MS; no tratamento CE3, 3 foram T, 14 MT, 30 MS e 3 sensíveis (S; no tratamento CE4, um foi MS e 49 S e, no tratamento CE5, todos foram S. O teor de proteína nos grãos foi influenciado pela salinidade e variou de genótipo para genótipo.To assess the tolerance of 50 cowpea genotypes under salinity, experiments were conducted in greenhouse covered with fiberglass sheets. The salinity treatments applied in terms of electrical conductivity of saturation extract of soil (EC were EC1 - 0.3; EC2 - 3.0; EC3 - 6.0; EC4 - 9.0 and EC5 - 12.0 dS m-1. The genotypes were classified for the salinity tolerance on the basis of the reduction in dry weight (% of shoot. Under EC2, 36 genotypes were tolerant (T, 12 moderately tolerant (MT and 2 moderately susceptible (MS; under EC3, 3 were T, 14 MT, 30 MS and 3 susceptible (S; under EC4, one was MS and 49 S and under EC5, all were S. The protein content of seed was influenced by salinity and varied with the genotype.

  20. Influencia de la salinidad sobre crecimiento y composición bioquímica de la cianobacteria Synechococcus sp.

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    2005-01-01

    Full Text Available El estudio de cianobacterias aisladas de ambientes hipersalinos es de interés debido a su versatilidad metabólica y ecofisiológica para adaptarse a condiciones extremas de salinidad, temperatura, irradiancia y limitación de nutrientes. Se reporta el efecto de la salinidad a 0‰, 35‰, 70‰ y 100‰ sobre el crecimiento, masa seca y producción de pigmentos, proteínas, carbohidratos y lípidos de la cianobacteria Synechococcus sp. Los bioensayos fueron mantenidos con medio ALGAL equivalente a 8 mM NaNO3, aireación constante, fotoperiodo 12:12 h, 28 ± 2ºC y 156 µmol quanta m–2 s–1 de irradiancia. La cianobacteria fue capaz de crecer bajo todas las salinidades probadas. La densidad celular fue mejorada a 35‰, con 607.64 ± 14.35 cél mL–1. A 100‰ se alcanzaron los máximos valores de masa seca, clorofila a, β-caroteno, zeaxantina, proteínas y carbohidratos con 3.87 ± 0.03 ng cél–1; 41.86 ± 0.39 fg cél–1; 9.03 ± 0.15 fg cél–1; 9.74 ± 0.24 fg cél–1; 1.95 ± 0.05 y 1.80 ± 0.05 pg cél–1, respectivamente. Sin embargo, el mayor contenido de lípidos fue alcanzado a 0‰ con 0.45 ± 0.04 pg cél–1. Esta cepa halotolerante de la cianobacteria Synechococcus muestra capacidad para modular la producción de biomasa enriquecida con pigmentos, proteínas, carbohidratos y lípidos en función de la salinidad.

  1. Preferencia y rangos de tolerancia a la temperatura y salinidad de los pterópodos y heterópodos frente a la costa ecuatoriana

    OpenAIRE

    CRUZ, M.

    2012-01-01

    Del análisis de 216 muestras de zooplancton, obtenidos mensualmente desde 1990 hasta el 2007, en la estación fija a 10 millas de la costa ecuatoriana, frente a Salinas, Ecuador, se identificaron 14 especies de gasterópodos planctónicos (Pterópodos y heterópodos) a los que se le analizaron la preferencia de las masas de aguas y sus rangos de tolerancia a la temperatura y salinidad en el mar. Los registros mensuales de la temperatura y salinidad superficial del agua, fueron relacionados con la ...

  2. Salinidade da Água e Biofertilizante Bovino: Efeito sobre a Biometria do Pimentão

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    Vinícius Batista Campos

    2009-10-01

    Full Text Available Objetivou-se avaliar o efeito da salinidade da água de irrigação e biofertilizante bovino no comportamento vegetativo do pimentão, cultivar “All Big”. O experimento foi conduzido em abrigo telado, utilizando como substrato material dos primeiros 10 cm de um Latossolo Amarelo Distrófico, acondicionado em vasos de 3 L, adotando-se o delineamento inteiramente casualizado, em esquema fatorial 5x2 correspondente a condutividade elétrica da água (0,5; 1,0; 2,0; 3,0 e 4,0 dS m-1, na ausência e presença de biofertilizante bovino aplicado ao solo na forma líquida, diluído em água na proporção de 1:1. Aos 60 dias após a semeadura, a salinidade da água de irrigação influenciou negativamente a altura das plantas, número de folhas e área foliar do pimentão, contudo, em menor intensidade às plantas submetidas ao biofertilizante bovino. Apenas o diâmetro do caule não foi afetado pelos sais presentes na água de irrigação, mas essas plantas apresentaram diâmetro superior quando tratadas com o insumo.

  3. EVALUACIÓN DE LA TOLERANCIA A LA SALINIDAD BAJO CONDICIONES CONTROLADAS DE NUEVE CULTIVARES CUBANOS DE SOYA (Glycine max (L. Merril

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    Yuniet Hernández Avera

    2015-01-01

    Full Text Available La salinidad es una amenaza creciente para la productividad de cultivares de soya ( Glycine max (L. Merril. Diferentes estrategias se han adoptado para superar el problema de la baja productividad. El empleo de genotipos tolerantes a la salinidad es una buena opción para obtener rendimientos económicos en estas áreas. Por esta razón, es importante disponer de métodos rápidos para evaluar la tolerancia a este estrés sobre todo en las primeras etapas de su crecimiento. El objetivo del presente estudio fue evaluar la tolerancia a la salinidad en nueve genotipos de soya. Los experimentos se desarrollaron en casas verdes bajo condiciones controladas. El índice de tolerancia a la salinidad de germinación (IG, longitud de los brotes (ILB, longitud de la raíz (ILR, materia seca de brotes (IMSB y de la raíz (IMSR, así como la lesión de la membrana celular se midieron en todos los genotipos tratados con NaCl en concentraciones de 0 y 150 mM. Los resultados, a partir de los criterios fisiológicos, permitieron identificar a los cultivares AT22 e INCASoy36 como los más tolerantes en comparación con el resto de los genotipos, por lo que pueden considerarse como prometedores para elevar la productividad en las zonas afectadas por la sal.

  4. Cultivo de girassol em sistema hidropônico sob diferentes níveis de salinidade Sunflower cultivation in a hydroponic system under different salinity levels

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    José Amilton Santos Júnior

    2011-12-01

    Full Text Available Os sistemas hidropônicos tem se constituído em uma das alternativas para equacionar os fatores naturais adversos à produção agropecuária presentes nas regiões semiáridas do Brasil, como solos rasos, pedregosos e pouco férteis, além da escassez de recursos hídricos em quantidade e qualidade (teores elevados de sais. Este trabalho buscou estudar os componentes de produção do girassol (variedade EMBRAPA 122/V-2000 destinados à obtenção de aquênios e forragem (fitomassa, cultivado em sistema hidropônico, utilizando a fibra de coco como substrato e irrigado com água salobra de diferentes salinidades. O delineamento experimental utilizado foi o inteiramente casualizado, em esquema fatorial 5 x 2 com três repetições, de modo que foram estudados cinco níveis de salinidade e duas densidades de plantio - uma ou duas plantas por vaso. As águas de irrigação foram compostas por 50% da solução nutritiva padrão e 50% de água de abastecimento, adicionada de níveis crescentes de NaCl, resultando em uma condutividade elétrica final da solução (CEs de 1,7; 4,3; 6,0; 9,0 e 11,5 dS m-1. Verificou-se que a densidade diferenciada das plantas de girassol afetou positivamente os componentes de produção de aquênios e fitomassa da cultura indicando maior viabilidade quando se utiliza duas plantas por vaso.Hydroponic systems have constituted an alternative for combating the adverse natural factors of agricultural production in the semi-arid regions of Brazil, such as shallow rocky and infertile soils, and the scarcity of good quality water resources (high salt content. This work studied the yield of the sunflower (variety EMBRAPA 122/V-2000 destined for achene and fodder (phytomass production, grown hydroponically, using coconut fiber as substrate and irrigated with brackish water of varying salinities. The experimental layout used was completely randomized into a 5 x 2 factorial design with three replications, five levels of water

  5. Evolución de la salinidad en un suelo irrigado del sudoeste bonaerense Soil salinity evolution under irrigation in southwestern Buenos Aires

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    María Elina Aguirre

    2011-12-01

    Full Text Available Este trabajo es un estudio de la influencia del riego por goteo sobre la salinidad y sodicidad del suelo en una plantación de olivo de 50 años de edad, cercana a la localidad de Faro, distrito de Coronel Dorrego, provincia de Buenos Aires. El agua utilizada tiene una conductividad eléctrica de 2,1 dSm-1 y una relación de adsorción de sodio (RAS 13,8. El sistema de irrigación está compuesto por dos líneas de goteros por fila de árboles. Los emisores presentan un caudal de 1 Lh-1 y están espaciados a 0,7 m. La toma de muestras se efectuó en una parcela de 50 por 1.000 m, cuatro muestras al inicio, dos en el medio y dos al final. En cada ubicación se tomaron muestras para cada uno de los cuatro horizontes del perfil, debajo del gotero y entre goteros. La salinidad y la sodicidad fueron analizadas en relación con los valores experimentales de la conductividad eléctrica (CEes y los de RAS calculados, ambos de los extractos de saturación de las muestras. Después de tres temporadas de irrigación se determinó que a la CEes se incrementa hasta valores cercanos a los del agua de irrigación, b el incremento de RAS es superior en diez veces los valores iniciales. De acuerdo con esto la aparición de problemas de sodicidad es altamente probable sin una enmienda del RAS del agua de irrigación. El comportamiento observado implica la siguiente cuestión: ¿el tipo y concentración de sales del agua de irrigación y las condiciones climáticas son compatibles para el cultivo sustentable del olivo en el sudoeste bonaerense? Para contestar esta pregunta se necesitan estudios posteriores en un período de tiempo más amplio, ya que la mayoría de los sitios muestreados no exhiben estabilidad temporal en relación con las condiciones promedio de salinidad y alcalinidad del suelo.The objective of this study was to elucidate the effect of drip irrigation on the salinity and sodicity of the soil under a 50-year old olive plantation, located near the

  6. Salinidade da Água e Biofertilizante Bovino: Efeito sobre a Biometria do Pimentão

    OpenAIRE

    Vinícius Batista Campos; Lourival Ferreira Cavalcante

    2009-01-01

    Objetivou-se avaliar o efeito da salinidade da água de irrigação e biofertilizante bovino no comportamento vegetativo do pimentão, cultivar “All Big”. O experimento foi conduzido em abrigo telado, utilizando como substrato material dos primeiros 10 cm de um Latossolo Amarelo Distrófico, acondicionado em vasos de 3 L, adotando-se o delineamento inteiramente casualizado, em esquema fatorial 5x2 correspondente a condutividade elétrica da água (0,5; 1,0; 2,0; 3,0 e 4,0 dS m-1), na ausência e pres...

  7. Crecimiento y composición bioquímica de limnothrix sp. a diferentes salinidades y concentraciones de nitrato

    OpenAIRE

    Nathalie Lemus; Miguel Angel Guevara Acosta; César Lodeiros; Aleikar Vásquez; Luis Freites; Berenice Licet

    2013-01-01

    Título en ingles: Growth and biochemical composition of Limnothrix sp. at different salinities and concentrations of nitrateTítulo corto: Crecimiento y composición bioquímica de Limnothrix sp.ResumenSe evalúo el efecto de la salinidad  (15, 25 y 35 UPS) y concentración de nitrato (4, 8 y 16 mmoles L-1) sobre el crecimiento y composición bioquímica de la  cianobacteria Limnothrix sp. (LAEP- 52) con miras a su explotación para fines biotecnológicos. La cianobacteria se cultivó durante 20 días...

  8. Interação entre salinidade e bioestimulante no crescimento inicial de pinhão-manso

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    Francisco de A. de Oliveira

    2015-03-01

    Full Text Available Objetivou-se avaliar a interação entre salinidade e o uso de bioestimulante sobre o crescimento inicial de pinhão-manso. O experimento foi desenvolvido nos meses de agosto a outubro de 2012, na Universidade Federal Rural do Semi-Árido, em Mossoró, RN, utilizando o delineamento inteiramente casualizado, em esquema fatorial 2 x 4. Os tratamentos foram obtidos da combinação de dois níveis de sais da água de irrigação (0,5 e 5,0 dS m-1 e quatro intervalos de aplicação de bioestimulante (I1 – Ausência; I2 - 7 dias; I3 - 14 dias; I4 – 21 dias. Utilizou-se o fitorregulador comercial Stimulate® 10X, na concentração padrão de 18 mL L-1 de solução e se avaliaram as seguintes variáveis: altura, diâmetro do caule, comprimento da raiz principal, número de folhas, área foliar, massa seca de folhas, massa seca de caule, massa seca de raiz, massa seca total e razão massa seca da parte aérea/massa seca de raiz. O estresse salino provocou redução em todas as variáveis avaliadas e inibiu o efeito do bioestimulante nos intervalos utilizados. O uso de Stimulate® 10X não inibiu o efeito deletério da salinidade da água de irrigação sobre o crescimento inicial do pinhão-manso.

  9. Crecimiento y composición bioquímica de Limnothrix sp. a diferentes salinidades y concentraciones de nitrato

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    Nathalie Lemus

    2013-06-01

    Full Text Available Normal 0 21 false false false MicrosoftInternetExplorer4 Título en ingles: Growth and biochemical composition of Limnothrix sp. at different salinities and concentrations of nitrateTítulo corto: Crecimiento y composición bioquímica de Limnothrix sp.ResumenSe evalúo el efecto de la salinidad  (15, 25 y 35 UPS y concentración de nitrato (4, 8 y 16 mmoles L-1 sobre el crecimiento y composición bioquímica de la  cianobacteria Limnothrix sp. (LAEP- 52 con miras a su explotación para fines biotecnológicos. La cianobacteria se cultivó durante 20 días a 25°C, 98 µmol m-2s-1, fotoperiodo 12:12 y aireación continua (200 mL min-1. El crecimiento fue evaluado cada 48 horas a través de la medición  de la densidad óptica a 730 nm. Se evidenció que la salinidad y la concentración de nitrato modulan el crecimiento y la composición bioquímica de Limnothrix sp. El mayor crecimiento (6.3 ± 0.38 mg mL-1, contenidos de proteínas (57 ± 4.56 %, ficocianina (170.3 ± 13.6 µg mL-1  y clorofila a (16 ± 1.28 µg mL-1 se obtuvieron a  la menor salinidad (15 UPS y mayor concentración de nitrato (16 mmoles L-1. Por el contrario, las mayores concentraciones  de lípidos (21.3± 1.19 %, carbohidratos (14.47 ± 1.15 % y carotenoides (6 ± 0.48 µg mL-1 se lograron en la mayor salinidad (35 UPS y menor concentración de nitrato (4 mmoles L-1. La producción de exopolisacáridos sólo fue influenciada por la salinidad, llegando a alcanzar sus mayores valores a 35 UPS (1600 ± 112.25 mg L-1. Los contenidos de proteínas, lípidos, carbohidratos y pigmentos obtenidos en esta cianobacteria permiten catalogarla como un organismo que puede ser usado en las industrias biotecnológicas, ya sea como alimento para organismos cultivados o como fuente de metabolitos de interés industrial. Palabras clave: cianobacteria, biotecnología, LimnothrixAbstractIn this research we evaluate the effect of salinity (15, 25 and 35 UPS and nitrate concentration (4, 8

  10. EFECTOS DE LA SALINIDAD EN LAS VARIABLES HÍDRICAS POTENCIALES HÍDRICO Y OSMÓTICO Y AJUSTE OSMÓTICO EN CULTIVARES CUBANOS DE TRIGO (Triticum aestivum L. Y T. durum L.

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    Leandris Argentel

    2013-01-01

    Full Text Available El experimento se desarrolló con el objetivo de evaluar el efecto de la salinidad en los potenciales hídrico y osmótico y el ajuste osmótico en 12 cultivares de trigo pertenecientes a las especies Triticum aestivum L. y Triticum durum L., en etapas iniciales del desarrollo, siguiendo las metodologías para su determinación. Las plantas se establecieron en un invernadero en condiciones de hidroponía aplicando, como primer tratamiento, una solución nutritiva salinizada a base de NaCl a una conductividad eléctrica de 8 dS.m-1. El tratamiento control consistió en la solución nutritiva sin salinidad significativa (0,36 dS.m-1. Las evaluaciones se realizaron a los 25 días posteriores a la germinación. Los resultados mostraron una significativa disminución de los valores del potencial hídrico en la mayoría de los cultivares en todos los órganos medidos y se observó una significativa disminución de sus valores desde las raíces hasta las hojas para asegurar el gradiente hídrico. Los cultivares que no disminuyeron significativamente su potencial hídrico mostraron comportamiento similar en los tres órganos evaluados aunque el gradiente de potenciales se mantuvo. El potencial osmótico disminuyó significativamente en todos los cultivares y sus valores fueron inferiores a -0,6 MPa. Todos los cultivares realizaron el ajuste osmótico, siendo el valor más significativo AO= 0,3 MPa en los cultivares INIFAT RM-36, INIFAT RM-32, INIFAT RM-37. Se observó variabilidad en la respuesta al estrés salino entre los cultivares y especies para las tres variables evaluadas.

  11. INDICADORES DEL CRECIMIENTO INICIAL Y DEL ESTADO NUTRICIONAL PARA LA SELECCIÓN TEMPRANA DE GENOTIPOS DE ARROZ (Oryza sativa L. TOLERANTES A LA SALINIDAD

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    Alexis Lamz Piedra

    2015-01-01

    Full Text Available Con el objetivo de determinar posibles indicadores del crecimiento inicial y nutricionales para la selección temprana de genotipos de arroz tolerantes a la salinidad, se desarrollaron ensayos con dos cultivares con diferente grado de tolerancia a la salinidad ('Pokkali' y 'Amistad- 82' en condiciones controladas, con soluciones salinas ajustadas a conductividades eléctricas (CE de 8 y 12 dSm-1 mediante la adición de NaCl y un control con agua destilada. Se evaluó el porcentaje de germinación a los 15 días después de la siembra (DDS y los parámetros del crecimiento altura de la planta, longitud de la raíz, masa seca de la parte aérea (MSPA, masa seca del sistema radical (MSSR a los 21 DDS. En tanto, en hojas y raíces de ambos cultivares, en condiciones semicontroladas y utilizando soluciones nutritivas para la simulación del estrés salino, con CE de 8 y 12 dSm-1, se determinó en estado de plántula, el contenido de nitrógeno (N, fósforo (P, potasio (K, sodio (Na, así como la relación sodio/potasio. Los resultados evidencian un comportamiento diferencial de los cultivares en cuanto a su grado de tolerancia a la salinidad, lo que permite usar algunas de las variables evaluadas, como indicadores para la discriminación de genotipos de arroz tolerantes a salinidad.

  12. Salinity reduced growth PS2 photochemistry and chlorophyll content in radish Crescimento reduzido por salinidade, fotoquímica PS2 e conteúdo de clorofila em rabanete

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    Muhammad Jamil

    2007-01-01

    Full Text Available When plants are grown under saline conditions, photosynthetic activity decreases leading to reduced plant growth, leaf area, chlorophyll content and chlorophyll fluorescence. Seeds and seedlings of radish (Raphanus sativus L. were grown in NaCl solutions under controlled greenhouse conditions. The NaCl concentrations in complete nutrient solutions were 0 (control, 4.7, 9.4 and 14.1 dS m-1. The salinity reduced germination percentage and also delayed the germination rate as the salt level increased. Lengths and fresh weights of root and shoot decreased with the increasing salt concentration. Furthermore, photochemical efficiency of PS2 (Fv/Fm, photochemical quenching coefficient (qP, non photochemical quenching coefficient (qN, leaf area and chlorophyll content (SPAD value were also reduced (P Quando plantas crescem sob condições de salinidade, sua atividade fotossintética diminui levando a um crescimento reduzido, menor área foliar, conteúdo de clorofila e fluorescência de clorofila. Sementes e plântulas de rabanete (Raphanus sativus L. foram germinadas e conduzidas em soluções de NaCl sob condições controladas de casa de vegetação. As concentrações de NaCl adicionado a solução nutritiva completa foram 0 (Controle, 4,7; 9,4 e 14,1 dS m-1. A salinidade diminui a percentagem de germinação e também atrasou a taxa de germinação com o aumento do nível de sal. Comprimento e peso fresco da parte aérea e da raiz decresceram com o aumento da concentração salina. Além disso, a eficiência fotoquímica de PS2 (Fv/Fm, o coeficiente fotoquímico de 'quenchin" (q p, o coeficiente não fotoquímico de "quenching" (q n, a área foliar e o teor de clorofila (valor SPAD também foram reduzidos (P < 0,001 por estresse de sal. Ao contrário, a relação Fo/Fm aumentou com a concentração salina, ao passo que a salinidade não teve efeito sobre a eficiência de excitação capturada pelo PS2 aberto (Fv'/Fm', taxa de transporte eletr

  13. Resposta de cultivares de alface à salinidade da solução nutritiva com rejeito salino em hidroponia Response of lettuce cultivars to nutrient solution salinity with saline rejects in hydropony

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    Nildo da S Dias

    2011-10-01

    Full Text Available No processo de dessalinização se gera, além da água potável, um rejeito altamente salino e de poder poluente elevado, o qual pode ser utilizado na produção agrícola rentável dependendo da adoção de práticas culturais adequadas e da tolerância das plantas às condições salinas. Nos últimos anos a tendência tem sido a substituição da agricultura convencional por sistemas hidropônicos de cultivos, considerados um dos mais eficientes no uso de água. O objetivo desta pesquisa foi analisar a resposta de duas cultivares de alface sob sistema hidropônico de cultivo (Lactuca sativa L., cvs. Verônica e Babá de verão em diferentes níveis de salinidade da solução nutritiva preparadas com água de abastecimento, água de rejeito coletada no dessalinizador e da sua diluição com água de abastecimento a 75, 50 e 25%, resultando em condutividades elétricas da solução nutritiva (CEs de 1,1; 2,4; 3,6; 4,7 e 5,7 dS m-1 após as diluições e adição de fertilizantes. Ocorreu variação genotípica sob as variáveis de crescimento e produção da alface, exceto para o número de folhas, sendo a cultivar Babá de verão a que produziu maior rendimento, independentemente do nível de salinidade e, portanto, a cultivar mais tolerante à salinidade da água com rejeito salino.In desalination process, besides the potable water, highly salty and polluted water (brine is generated, which can be used for producing profitable crops depending on the adequate cultural practices as well as on the plant ability of reacting to saline conditions. The trend in recent years has been towards conversion of conventional agriculture to soilless agriculture which is considered to be a more efficient use of water system. The aim of this research was to examine the response of two lettuce cultivars (Lactuca sativa L. cvs. Veronica, Babá de verão under hydroponic system to different levels of salinity of the nutrient solutions prepared with tap water

  14. Estudo comparativo do crescimento de plantas de tomate e milho sob condições de salinidade

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    Egídio Bezerra Neto

    1999-01-01

    Full Text Available Plantas de tomate (Lycopersicum esculentum Mill e de milho (Zea maiz L. foram cultivadas em meio hidropônico, em presença de 0 ou 100 mmol de NaCl por litro de solução nutritiva. Trinta dias após o início da aplicação dos tratamentos foi realizada coleta para a análise dos parâmetros de crescimento. A taxa de crescimento absoluto de ambas as espécies diminuiu com a salinidade. O tratamento salino não afetou a alocação de biomassa das folhas, provocou uma diminuição na alocação da biomassa do caule e aumento da alocação da biomassa das raízes das plantas de tomate e de milho. Ocorreu uma redução de 48,01 % na área foliar das plantas de milho e de 58,75 % nas de tomate, devido ao tratamento salino. A razão de área foliar nas plantas de milho foi reduzida em 14,07 % enquanto nas de tomate tratadas com cloreto de sódio aumentou 15,49 %. Os resultados obtidos sugerem que as plantas de milho são mais tolerantes à salinidade que as de tomate.Plants of tomato and maize were grown in hydroponic solution with and without the addition of sodium chloride in order to evaluate some growth parameters of one C3 and one C4 species. After 30 days under the saline stress treatment there was no significant difference between both species regarding to leaf biomass allocation. The stem biomass allocation decreased for both the tomato and the maize plants. This was due to salt treatment, while root biomass allocation increased. The Absolute growth rate was the most affected parameter by the NaCl treatment for which values were obtained for both species. The leaf area also decreased due to the sodium chloride treatment. The leaf area rate increased for the stressed tomato plants, while it tend to decrease for maize plants under saline treatment.

  15. Biología molecular de la regulación de la homeostasis de pH en Arabidopsis thaliana

    OpenAIRE

    Niñoles Rodenes, Regina

    2011-01-01

    La presente tesis doctoral se enmarca dentro del tema de la homeostasis de cationes en células vegetales. El conocimiento de los transportadores involucrados en la homeostasis de cationes y sus mecanismos de regulación, puede tener aplicaciones biotecnológicas para el desarrollo de plantas tolerantes a estreses abióticos como la salinidad o el pH ácido. El objetivo general del presente trabajo es determinar y estudiar los mecanismos implicados en la homeostasis de pH en Arabidopsis thalian...

  16. Tolerância da cultura do tomate à salinidade do solo em ambiente protegido Tolerance of tomato crop to salinity of soil in protected ambient

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    Pedro R. F. Medeiros

    2012-01-01

    Full Text Available Com o intuito de contribuir com os dados disponíveis na literatura sobre tolerância das culturas à salinidade do solo oriunda de sais fertilizantes, o presente trabalho tem, como objetivo, determinar a tolerância da cultura do tomate a salinidade do solo, a partir de dois manejos de fertirrigação e seis níveis iniciais de salinidade (1,0; 2,0; 3,0; 4,0; 5,0 e 6,0 dS m-1 a partir das variáveis produção e componentes de produção, em ambiente protegido com solo franco-argiloso. O experimento foi realizado no Departamento de Engenharia de Biossistemas da ESALQ/USP, Piracicaba,SP. O delineamento estatístico foi aleatorizado em blocos, com 4 repetições, concluindo que a produção e os componentes de produção da cultura do tomate foram afetados estatisticamente, tanto pelo tipo de manejo de fertirrigação quanto pelos níveis de salinidade do solo, com redução na tolerância da cultura do tomate, passando a ser classificada sensível à salinidade do solo.In order to contribute to data available in the literature on tolerance of crops to soil salinity derived from fertilizer salts, the present study aims to determine the tolerance of tomato crop to the soil salinity, based on two managements of fertirrigation and six initial levels of salinity (1.0; 2.0; 3.0; 4.0; 5.0 and 6.0 dS m-1 from the variables production and components of production, in a protected environment with sandy-clay soil. The experiment was conducted at the Department of Biosystems Engineering of ESALQ/USP, Piracicaba/SP. The experimental design was in randomized blocks, with 4 repetitions. Concluding that the production and the components of production of tomato crop were significantly affected both by the type of management of fertirrigation and by the levels of soil salinity, with a reduction in the tolerance of tomato crop, being classified as sensitive to soil salinity.

  17. Crescimento de mudas de moringa em função da salinidade da água e da posição das sementes nos frutos

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    Francisco de Assis de Oliveira

    2013-02-01

    Full Text Available A escolha das sementes é de fundamental importância para a obtenção de mudas de qualidade, principalmente quando são produzidas sob condições ambientais adversas. Este trabalho foi desenvolvido com o objetivo de avaliar a influencia da salinidade sobre o desenvolvimento de mudas de moringa provenientes de sementes localizadas em diferentes posições no fruto. O delineamento utilizado foi o inteiramente casualizado, com os tratamentos arranjados em esquema fatorial 3 x 4 e quatro repetições. Os tratamentos resultaram da combinação de três posições de sementes no fruto (basal, mediana e apical com quatro níveis de salinidade da água de irrigação (0,5; 2,0; 3,5; e 5,0 dS m-1. Foram avaliadas as seguintes características de crescimento: altura (ALT, diâmetro do caule (DC, diâmetro da raiz principal (DRP, número de folhas (NF, área foliar (AF, massa seca da parte aérea (MSPA, massa seca do sistema radicular (MSR e massa seca total (MST. Os dados foram submetidos à análise de variância pelo teste F e as médias, comparadas pelo teste de Tukey a 5% de probabilidade, para o efeito da posição da semente no fruto; e por análise de regressão, para os dados provenientes da salinidade. Houve interação significativa na maioria das características avaliadas. A salinidade da água de irrigação diminuiu em todas as variáveis. As mudas provenientes de sementes localizadas na porção basal dos frutos foram mais afetadas pela salinidade da água de irrigação.

  18. Controlo da salinidade do solo com recurso à sementeira directa Control of the soil salinity by using direct drilling

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    J. P. Mendes

    2009-01-01

    Full Text Available A introdução do regadio utilizando água com teores moderados de sais, em zonas de clima semi-árido e em solos com má drenagem interna, conduz, a prazo, ao inevitável aumento da salinidade do solo e, provavelmente, ao risco de alcalização do mesmo. A maior parte das áreas de regadio, a beneficiar com as águas provenientes do Alqueva, enquadram-se nesta circunstância. No presente estudo, pretende-se averiguar se, o aumento da infiltrabilidade do solo e a redução da evaporação directa, conseguida com uma elevada quantidade de resíduos à superfície do solo provenientes de uma cultura de cobertura seguida de s ementeira directa, possibilitam uma menor acumulação dos sais durante o Verão e uma maior lavagem, dos mesmos, durante o Inverno. Para testar a sementeira directa com cultura de cobertura, como tecnologia para o controlo da salinidade, a longo prazo, em clima semi-árido e solos mal drenados, instalou-se um ensaio no Alto Alentejo no perímetro de rega do Caia, em Luvissolos Cálcicos (classificação FAO. O ensaio decorreu debaixo de uma rampa rotativa e tem como tratamentos principais dois sistemas de preparação do solo: sementeira directa sobre cultura de cobertura (SD; sistema convencional (SC, subdividido em dois níveis de salinidade da água (0,7 dS m-1 e 2 dS m-1 e em dois regimes hídricos (100% e 70% da ETc do SC. O regime hídrico mais baixo foi obtido por redução do diâmetro dos bicos dos aspersores numa coroa circular da rampa rotativa e as diferentes qualidades da água foram obtidas por aplicação de cloreto de sódio e de sulfato de magnésio à superfície do solo como se se tratasse de um fertilizante de cobertura, sólido. Ao fim do segundo ano de ensaio, os valores de salinidade da solução do solo (1:2 em peso nos primeiros 0,20 m são inferiores na sementeira directa (0,63 dS m-1 para a SD e 0,75 dS m-1 para o SC e as diferenças são mais acentuadas no regime hídrico mais elevado. Os valores

  19. Variaciones en el pH de la rizosfera y en el porcentaje de materia seca de Vicia sativa al aplicar dos fuentes fosfatadas de baja solubilidad en un andisol del departamento de Nariño, Colombia

    Directory of Open Access Journals (Sweden)

    Menjivar F. Juan Carlos

    2006-06-01

    Full Text Available

    En el estudio se utilizaron seis tratamientos: el testigo (T0, sin fuentes fosfatadas (T1 y con adiciones de 25 y 50 kg/ha de P como fosforita Huila (T2 y T3 y calfós (T4 y T5. Los cambios generados por la raíz se evaluaron utilizando la solución nutritiva de Marschner Römheld y Ossenberg-Neuhaus, acondicionada con agar. El porcentaje de materia seca parcial de Vicia sativa se incrementó significativamente al aplicar 25 y 50 kg/ha de P como fosforita Huila (T2 y T3 y calfos (T5 y T6 en la localidad de Genoy. El pH de la solución agarizada sufrió disminuciones significativas a través del tiempo especialmente en los tratamientos T3 y T2.

    Palabras claves: pH rizosférico, Vicia sativa, Papilionoidea, fuentes fosfatadas, solubilidad

  20. Effect of calcium and magnesium silicate on the growth of the castor oil plant subjected to salinity levels Efeito de silicato de cálcio e magnésio sobre o crescimento de plantas de mamoneira submetidas a níveis de salinidade

    Directory of Open Access Journals (Sweden)

    José Félix Brito Neto

    2012-12-01

    Full Text Available Salt stress decreases the osmotic potential of soil solution causing water stress, causing toxic effects in the plants resulting in injuries on the metabolism and nutritional disorders, thus compromising the plant growth, resulting in lower production. The calcium silicate and magnesium can perform the same function as limestone, besides providing silicon to plants, may also contribute to the resistance of plants to salt stress. Thus, the objective of this study was to evaluate the effect of calcium and magnesium silicate on the growth of the castor oil plant BRS Energia cultivated under saline conditions. This study evaluated plant height, stem diameter, number of leaves, leaf area, dry weight of shoot and root, and soil chemical characteristics. There was no interaction between factors of salinity level and of silicate level regarding the evaluated variables. There was a direct relationship between salinity levels and plant growth in height and stem diameter. The K concentration in soil were affected by salinity levels. O estresse salino diminui o potencial osmótico da solução do solo causando estresse hídrico, provocando efeitos tóxicos nas plantas que resultam em injúrias no metabolismo e desordens nutricionais, comprometendo assim o crescimento das plantas, resultando em menor produção. O silicato de cálcio e magnésio pode desempenhar a mesma função do calcário, além de fornecer silício para as plantas, podendo ainda, contribuir para a resistência de plantas ao estresse salino. Nesse sentido, objetivou-se com esse trabalho avaliar o efeito do silicato de cálcio e magnésio no crescimento da mamoneira BRS Energia cultivada sob condições salinas. Avaliou-se a altura da planta, diâmetro do caule, número de folhas, área foliar, massa seca da parte aérea e da raiz e as características químicas do solo. Não houve interação entre os fatores níveis de salinidade e silicato sobre as variáveis analisadas. Houve rela

  1. Caracterización de la reactividad conductual frente al manejo y su relación con el Cortisol sanguíneo, contusiones y pH de la carne en novillos

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    I De Freslon

    2014-01-01

    Full Text Available Con el motivo de indagar en la predicción de la incidencia de pH elevado (corte oscuro en base a pruebas conductuales aplicables en situaciones comerciales, se evaluó la relación entre la reactividad conductual y parámetros fisiológicos y de calidad de carne en novillos. Cuarenta y dos novillos fueron pesados individualmente en una báscula de 2,5x3x2,5m para evaluar dos parámetros conductuales: el grado de reactividad y la velocidad de salida. Para determinar la consistencia de las respuestas, se calculó la repetibilidad de las respuestas durante tres pesajes y se creó una escala cualitativa de consistencia. La concentración de cortisol sérico fue determinada post-pesaje en el predio y al desangrado, las contusiones y el pH fueron registrados en la canal. El grado de reactividad fue altamente repetible (r = 0,81-0,87 y la velocidad de salida medianamente repetible (r = 0,44-0,60, sin embargo, se detectaron diferencias individuales en la "habituación" y "sensibilización" a la prueba. Los animales con mayor grado de reactividad tuvieron mayores concentraciones de cortisol sérico en el predio. No hubo asociación entre las respuestas conductuales, las contusiones en la canal y el pH final de la carne. Novillos cuyas canales presentaron múltiples contusiones (3-4 tuvieron una concentración de cortisol promedio al desangrado significativamente (P < 0,05 más alta que novillos con menos contusiones en la canal. Se concluye que la reactividad debe ser medida en forma seriada y se recomienda indagar más sobre la capacidad de las pruebas de reactividad para detectar diferencias en reactividad que puedan reflejarse en diferencias en parámetros de calidad de la carne.

  2. Descoloração de corantes têxteis por fungos ligninolíticos em condições de pH e salinidade elevada

    OpenAIRE

    Ottoni, C. A.

    2012-01-01

    Tese de doutoramento em Engenharia Quimica e Biológica O principal objetivo deste trabalho consistiu em selecionar e avaliar diferentes estirpes de fungos da podridão branca da madeira (Fpb) quanto à capacidade de descoloração, em condições similares às apresentadas na indústria têxtil, utilizando o corante azo Reativo Preto 5 (RP5). O corante Poly R-478 (PR478) foi utilizado como parâmetro comparativo por ser considerado um indicador da atividade de enzimas existentes no si...

  3. Relações hídricas em cultivares de beterraba em diferentes níveis de salinidade do solo

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    Alexsandro O. da Silva

    2013-11-01

    Full Text Available O excesso de sais no solo pode afetar diretamente o desenvolvimento e a produtividade das plantas, motivo pelo qual investigações sob as relações hídricas das culturas em tais condições se fazem necessárias para prevenir ou remediar tal problema. O estudo foi conduzido em casa de vegetação, na Universidade Estadual Paulista no Departamento de Engenharia Rural. O delineamento estatístico adotado foi o de blocos casualizados com 4 repetições, 5 níveis de salinidade no solo (1,0; 3,0; 6,0; 9,0; 12,0 dS m-1, duas cultivares de beterraba (Early Wonder e Itapuã e dois manejos de fertirrigação totalizando, assim, 80 parcelas experimentais. Foram realizados medidas do teor relativo de água nas folhas, resistência difusa ao vapor de água, transpiração, área foliar e o consumo hídrico da cultura. Houve um decréscimo de acordo com o incremento da salinidade para os parâmetros fisiológicos analisados na cultivar Early Wonder enquanto para a cultivar Itapuã um aumento crescente foi observado até a salinidade de 6 dS m-1. O consumo de água pelas plantas apresentou uma redução para as duas cultivares estudadas.

  4. Ciclo estacional de nutrientes, temperatura, salinidad y clorofila a en Bahía Magdalena, B.C.S., México (2006-2007)

    OpenAIRE

    Cervantes Duarte, Rafael; López López, Silverio; González Rodríguez, Eduardo; Futema Jiménez, Sonia

    2010-01-01

    Durante el periodo de febrero de 2006 a diciembre de 2007 se midieron en la superficie del mar de 14 estaciones de muestreo en Bahía Magdalena (Baja California Sur, México), con una frecuencia bimestral y bajo condiciones de mareas vivas, las concentraciones de nitrógeno inorgánico disuelto (NID): nitrito (NO2), nitrato (NO3), amonio (NH4), fosfato (PO4), temperatura (T), salinidad (S) y concentración de clorofila a (Cla). La relación T-S mostró que las aguas más frías y menos salinas general...

  5. Efecto del aumento de salinidad en la fertilización de óvulos de erizos Strongylocentrotus franciscanus y Lytechinus anamesus Effect of increased salinity in the ovum fertilization of sea urchin Strongylocentrotus franciscanus and Lytechinus anamesus

    OpenAIRE

    B. Estela López-Ortiz; Alberto Sánchez

    2009-01-01

    Se evaluaron los efectos del incremento de salinidad sobre la fertilización de óvulos de erizos de mar de las especies Strongylocentrotus franciscanus Agassiz, 1863 y Lytechinus anamesus Clark, 1912, los cuales fueron colectados mediante buceo libre en la bahía de Todos Santos, Ensenada, B. C., México. La fertilización de los óvulos de cada especie de erizo se llevó a cabo en un intervalo de salinidad de 33.4 a 53.4‰, estimándose para cada caso su CL50. Los resultados indicaron que la c...

  6. Crescimento e tolerância à salinidade em três espécies medicinais do gênero Plectranthus expostas a diferentes níveis de radiação

    OpenAIRE

    M.A.C. Freitas; A.V. Amorim; A.M.E. Bezerra; Pereira, M S; M.C. Bessa; F.P. Nogueira Filho; C.F Lacerda

    2014-01-01

    No cultivo de plantas medicinais as condições de salinidade e de luz podem exercer influência no rendimento e na qualidade final da produção de biomassa. O objetivo deste trabalho foi avaliar o efeito de diferentes luminosidades e níveis de salinidade na água de irrigação sobre o crescimento e tolerância de três espécies de plantas do gênero Plectranthus. O ensaio foi conduzido em parcelas subsubdivididas com cinco repetições, sendo as parcelas referente ao fator ambiente (pleno sol e telado)...

  7. Impacto da salinidade no desenvolvimento e crescimento de mudas de carnaúba (Copernicia prunifera (Miller) H.E.Moore) Impact of salinity on development and growing of ‘carnaúba’ (Copernicia prunifera (Miller) H.E. Moore) seedlings

    OpenAIRE

    Samia J. R. Holanda; Francisca S. de Araújo; Maria I. Gallão; Sebastião Medeiros Filho

    2011-01-01

    Identificar o impacto da salinidade no desenvolvimento e crescimento de espécies resistentes a altas concentrações salinas é de fundamental importância para a recuperação de áreas salinizadas do semiárido nordestino brasileiro. Visando contribuir para a resolução desta problemática, o presente trabalho avaliou o efeito de diferentes níveis de salinidade para o desenvolvimento e o crescimento da carnaúba, espécie nativa e de extremo valor econômico para a região. Os níveis analisados foram: 0,...

  8. Oxydation catalytique du Phénol par le peroxyde d'hydrogène en présence d'argiles pontées par des espèces mixtes [Al-Cu

    Science.gov (United States)

    Abdellaoui, M.; Barrault, J.; Bouchoule, C.; Srasra, N. F.; Bergaya, F.

    1999-03-01

    Various processes can be used for the treatment of wastewater, but the one we feel to be important and more promising is the wet peroxide oxidation (WPO), in the presence of a solid catalyst, at atmospheric pressure and at room temperature. Different types of materials can be used as catalysts for such reactions, but as shown in previous studies dealing with phenol oxidation clays-based catalysts seem to be attractive. It is well known that natural clays are inactive in the phenol oxidation, but the intercalation of polymeric species changes their properties. When the clay is pillared with pure aluminum oxyhydroxides species, the d{001} spacing and the surface area increase, but the activity is very low. When the clay is pillared with mixed [Al-Cu] species, there is a strong increase of the phenol conversion. Nevertheless W (Wyoming) based solids are more active than H (Haîdoudi) or L (Laponite) based catalysts. The stability, the activity and the percentage of copper depend on the preparation method. Différentes techniques de traitements des eaux usées peuvent être utilisées, et l'une des plus prometteuses est l'oxydation voie humide par le peroxyde d'hydrogène en milieu aqueux dilué (WPO), en présence de catalyseurs supportés, à pression atmosphérique et à 25 ° C. Lors de cette étude, il a été montré que les argiles brutes sont inactives en oxydation du phénol. L'intercalation d'espèces hydroxyaluminiques conduit à une augmentation de la surface spécifique et de l'espace interlamellaire, mais la conversion du phénol reste faible. En revanche, l'insertion d'espèces mixtes [Al-Cu] confère au catalyseur une importante activité. En outre, la quantité de cuivre intercalé est très faible (cuivre dépendent fortement de la méthode de préparation.

  9. Estabelecimento do arroz irrigado e absorção de cátions em função do manejo da adubação potássica e do nível de salinidade no solo Initial growth of flooded rice and cation absorption according to potassium fertilizer management and soil salinity

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    Felipe de Campos Carmona

    2009-04-01

    Full Text Available O uso da água para a irrigação do arroz no Rio Grande do Sul, cujos mananciais hídricos têm ligação com o mar, pode ocasionar acúmulo de sais no solo em concentrações prejudiciais ao estabelecimento da cultura nos anos subsequentes, especialmente quando são aplicadas altas doses de fertilizante potássico na linha de semeadura. Este trabalho foi realizado com o objetivo de avaliar o efeito do manejo da adubação potássica sobre o estabelecimento e a absorção de cátions pelo arroz (cultivar IRGA 417 em um solo com diferentes níveis de saturação por Na. Foram utilizados um Planossolo Háplico com saturações por Na na troca de 5, 10 e 20 %; três manejos da adubação com cloreto de K equivalentes a 120 kg ha-1 de K2O a lanço; 120 kg ha-1 de K2O na linha de semeadura e 60 kg ha-1 de K2O na linha de semeadura, além de uma testemunha, sem adição de sal e de fertilizante, fatorial (3 x 3 + 1. O estande de plântulas não foi afetado pelos níveis de salinidade do solo e manejo da adubação potássica. A ontogenia da planta foi afetada pela salinidade, com atraso na emergência das plântulas. A salinidade do solo, a partir de 10 % de saturação por Na no complexo de troca, inibiu a absorção de K e reduziu o crescimento das plântulas de arroz, assim como diminuiu as relações K/Na, Ca/Na e Mg/Na no tecido. A interação entre manejo da adubação x salinidade reduziu o teor de Ca trocável no solo, aumentou o teor de Na na parte aérea e reduziu a relação Ca/Na na parte aérea do arroz.The use of water for rice irrigation in Rio Grande do Sul, Brazil, where the water courses are connected with the sea, may cause salt accumulation in the soil at harmful levels for the establishment of rice plants in the following years, especially when high rates of potassium fertilizer are applied in the plant rows. The study was carried out with the purpose of evaluating the effect of potassium chloride management on the establishment

  10. Performance of rocket cultivars under different nutritive solutions with salinity different. = Desempenho de cultivares de rúcula sob soluções nutritivas com diferentes salinidades.

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    Francisco de Assis de Oliveira

    2013-08-01

    Full Text Available The use of saline water for vegetable production is a major challenge for researchers and farmers. Cultivation in inert substrate can be an alternative, since the low matric potential can reduce the effect of salinity on plants. This study was conducted in a greenhouse at the Departamento de Ciências Ambientais e Tecnológicas da Universidade Federal Rural do Semi-Árido, Mossoró-RN, in order to evaluate the performance of two cultivars of rocket grown in substrate and fertilized with nutrient solutions of different salinities . Ten treatments were evaluated in a factorial 2 x 5, two cultivars (C1-Cultivada e C2-Folha Larga and five salinity levels of the nutrient solutions (S1-1.2; S2-2.2; S3-3.2; S4-4.2 and S5-5.2 dS m-1, usinga randomized design. Harvesting was performed at 30 days after sowing and evaluated the following variables: number of leaves, height, leaf area, total fresh and total dry mass. The salinity of the nutrient solution adversely affected the development of rocket, grown on a substrate, however, cultivation rocket substrate may be performed using electrical conductivity of the nutritive solution to 2.36 dS m-1 without loss in yield fresh pasta. The Folha Larga cultivar produced more total fresh and dry weight in relation to cultivar Cultivada, but to cultivar Cultivada has increased tolerance to salinity than cultivar Folha Larga. = O uso de água salina na produção de hortaliças é um dos principais desafios de pesquisadores e produtores rurais. O cultivo em substrato inerte pode ser uma alternativa, uma vez que o reduzido potencial matricial pode reduzir o efeito da salinidade sobre as plantas. O trabalho foi desenvolvido em ambiente protegido no Departamento de Ciências Ambientaise Tecnológicas da Universidade Federal Rural do Semi-Árido, Mossoró-RN, e objetivou-se avaliar o desempenho de duas cultivares de rúcula cultivadas em substrato e fertirrigadas com soluções nutritivas de diferentes salinidades. Foram

  11. Variabilidade espacial da salinidade de um solo aluvial no semi-árido Paraibano Spatial variability of soil salinity in an alluvial soil of the semi-arid region of Paraíba state

    Directory of Open Access Journals (Sweden)

    Lázaro Costa de Souza

    2000-04-01

    Full Text Available O objetivo deste trabalho foi estudar a variabilidade espacial do pH da pasta de saturação (pHps, condutividade elétrica do extrato de saturação (CEes e porcentagem de sódio trocável (PST de um solo aluvial afetado por sais. Foram coletadas amostras de solo nas camadas 0-20, 20-40 e 40-60 cm, numa área do Projeto de Irrigação Capoeira, localizado em São José do Bonfim, Estado da Paraíba, utilizando-se um esquema sistemático de amostragem numa malha regular de 10 x 15 m. Os dados foram analisados através da estatística descritiva e geoestatística. Verificou-se baixa variabilidade para o pHps (CV 60 %. Modelos esférico e gaussiano foram ajustados aos semivariogramas das variáveis que apresentaram estrutura de dependência espacial, tendo-se obtido alcances variando de 20 a 40 m. Os mapas de isolinhas da combinação da CEes e PST permitiram visualizar o padrão de variabilidade da salinidade e sodicidade, constituindo-se em uma ferramenta para a definição de estratégias de manejo edáfico e recuperação da área afetada.The objective of this work was to study the spatial variability of pH of saturation paste (pHsp, the electrical conductivity of saturation extract (ECe and the exchangeable sodium percentage (ESP in an alluvial salt affected soil. Soil samples were collected in 0 - 20, 20 - 40 and 40 - 60 cm depths, in an area of the Irrigation Project of Capoeira, located in São José do Bonfim - Paraíba (Brazil, following a systematic scheme of sampling in a 10 x 15 m mesh. The data were analyzed through the descriptive statistics and geostatistics. Low variability was observed for the pHsp (CV 60%. Spherical and gaussian models were adjusted to the experimental semivariograms of the variables that presented a spatial dependence structure. Structures of spatial dependence, with range varying from 20 to 40 m were observed. The maps of isohypsas of the combination of ECe and ESP allowed the visualization of the pattern of

  12. Sweet pepper production in substrate in response to salinity, nutrient solution management and training system Produção de pimentão cultivado em substrato em resposta à salinidade, manejo da solução nutritiva e sistema de condução

    Directory of Open Access Journals (Sweden)

    José S Rubio

    2011-09-01

    . Um experimento no delineamento de blocos casualizados em parcelas sub-subdivididas, com quatro repetições, foi utilizado para testar os efeitos da concentração da solução nutritiva (Hoagland completa ou meia-força iônica, sistemas de condução (dois ou três ramos por planta e a salinidade da água (salina ou não salina sobre o rendimento total e comercial, a qualidade dos frutos e a concentração de nutrientes minerais nos frutos. A salinidade diminuiu o rendimento dos frutos devido à menor massa da matéria fresca dos frutos, mas não diminuiu o número de frutos por planta. Tanto na presença como na ausência da salinidade, o maior rendimento de frutos foi obtido pelas plantas irrigadas com solução nutritiva de Hoagland meia força e conduzidas com três hastes por planta. A incidência de podridão apical aumentou com o aumento da condutibilidade elétrica na solução nutritiva e diminuiu na solução de Hoagland meia força. A salinidade diminuiu a qualidade dos frutos em todos os tratamentos devido à diminuição nos teores de PO4(2-, SO4(2-, Fe2+;3+, Cu1+;2+ e Mn2+, além do índice de formato do fruto. Da mesma maneira, as plantas salinizadas e irrigadas com a solução de Hoagland meia força e conduzidas com três hastes apresentaram menor concentração de glicose e de frutose na polpa do fruto. Com base nestes resultados, o rendimento comercial poderia ser aumentado com água não salina ou com salinidade moderada mediante a implementação de práticas culturais adequadas.

  13. Efeito da salinidade e modo de aplicação da água de irrigação no crescimento e produção de alho

    Directory of Open Access Journals (Sweden)

    Amorim Júlio Roberto de Araújo

    2002-01-01

    Full Text Available Na Paraíba é comum a irrigação do alho por aspersão utilizando águas salinas, o que pode causar sérios danos às plantas. Este trabalho, realizado em casa de vegetação, teve por objetivo avaliar os efeitos sobre crescimento e produção do alho a partir de dois modos de aplicação de água, molhando ou não a folhagem das plantas, combinados com cinco níveis de salinidade da água de irrigação, que variaram entre 0,6 e 3,0 dS m-1. O desenvolvimento das plantas foi avaliado aos 30, 60, 90 e 120 dias após o plantio (DAP. As plantas de alho foram relativamente tolerantes à salinidade na brotação de bulbilhos e crescimento até 30 DAP. No final do ciclo (90-120 DAP, a parte aérea da planta e a formação dos bulbos foram afetadas pelo molhamento da folhagem das plantas. A salinidade começou a afetar a parte aérea das plantas entre 30-60 dias, enquanto o bulbo passou a ser afetado entre 60-90 DAP. A fase final de formação do bulbo (últimos 30 dias do ciclo foi a mais sensível à salinidade. A razão bulbar não pode ser utilizada como parâmetro de avaliação de tolerância do alho à salinidade.

  14. Hongos ectomicorrícicos y la tolerancia a la salinidad en plantas Ectomycorrhizal fungi and tolerance to salinity in plants

    Directory of Open Access Journals (Sweden)

    SELENE AGUILAR-AGUILAR

    2009-03-01

    Full Text Available El proceso de salinización de los suelos constituye un problema generalizado a nivel global. En este sentido, los hongos ectomicorrícicos tienen una importante participación en la recuperación de suelos forestales ya que involucran una serie de mecanismos celulares que pueden contribuir a la tolerancia a la salinidad en plantas que habitan los bosques templados o boreales. La participación de los hongos ectomicorrícicos en la tolerancia a la salinidad involucra la regulación homeostática de los iones, la mejora de captación de agua y la inducción de genes específicos en las raíces colonizadas. Los hongos ectomicorrícicos pueden estimular la presencia de osmolitos como la prolina, azúcares y polioles que contribuyen en la protección de las células vegetales. Además, estos organismos inducen la síntesis de enzimas antioxidantes y glutatión que participan en la disminución de especies reactivas de oxígeno. Esta revisión ofrece una descripción de la participación de los hongos ectomicorrícicos en la tolerancia a la salinidad en plantas.The process of salinization of the soil is a widespread problem at the global level. In this sense, ectomycorrhizal fungi have an important role in the recovery of forest soil, as it involves a number of cellular mechanisms that may contribute to the salinity tolerance in plants that inhabit temperate and boreal forests. The participation of ectomycorrhizal fungi on the salinity tolerance involves the ion-homeostasis regulation, improving uptake water and inducing specific gene in roots colonized. Likewise ectomycorrhizal fungi can stimulate the presence of osmolytes as proline, sugars and polyols that contribute to the protection of plant cells. Additionally, these organisms stimulate the synthesis of glutathione and antioxidant enzymes involved in the decrease of reactive oxygen species. This review provides an overview of participation of ectomycorrhizal fungi in the salinity tolerance in

  15. EVALUACIÓN DE TECNOLOGÍAS PARA LA RECUPERACIÓN DE SUELOS DEGRADADOS POR SALINIDAD EVALUATION OF TECHNOLOGIES FOR THE RECOVERY OF SOILS DEGRADED BY SALINITY

    Directory of Open Access Journals (Sweden)

    Orlando Zúñiga Escobar

    2011-06-01

    Full Text Available La presencia de salinidad y sodio en los suelos interfiere en el crecimiento adecuado de la mayoría de los cultivos y por lo tanto constituye uno de los problemas más serios que enfrenta la agricultura sostenible. Se evaluaron una serie de tecnologías no convencionales utilizadas en recuperación de suelos afectados por salinidad según la respuesta agronómica de un cultivo de maíz. Se planteó la aplicación de 3 tratamientos alternativos: 1 Biofertilizantes, 2 Biopolimeros y 3 Electromagnetismo comparados frente a la propuesta: 4 Convencional con base en la teoría del USDA (United States Departament of Agriculture de enmiendas químicas (yeso - azufre. Además de un testigo absoluto (Sólo drenaje. Los tratamientos más efectivos en cuanto respuesta fisiológica y productividad fueron los biológicos con uso de microorganismos (biofertlizantes y electromagnetismo, se incluyó la estimulación electromagnética la cual acelera la actividad microbiana para disminuir el tiempo de recuperación de suelos afectados por salinidad del suelo.Salinity and sodium content in soils interferes with proper growth of most crops and therefore constitutes a serious problem facing sustainable agriculture. The objective of this research was to evaluate a series of unconventional technologies used in recovery of salt-affected soils according to the agronomic response of a maize crop. The application of three alternative treatments with Biofertilizers, Biopolymers and Electromagnetism were proposed to make a comparison with the USDA-based conventional theory approach (United States Department of Agriculture of chemical amendments (gypsum - sulfur. In addition to an absolute control (drainage only. The most effective treatments in terms of physiological response and productivity were the biological using microorganisms (biofertilizers and electromagnetism, clarifying that electromagnetic stimulation was included to accelerate microbial activity and lower soil

  16. Crescimento e produção de manjericão em sistema hidropônico NFT sob salinidade

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    Maria A. A. Bione

    2014-12-01

    Full Text Available No semiárido brasileiro a falta de água de boa qualidade tem justificado o desenvolvimento de pesquisas científicas no aproveitamento de águas salobras. No presente trabalho avaliaram-se os efeitos de águas salobras em relação ao crescimento e à produção de plantas de manjericão em hidroponia, de outubro a novembro de 2012. Os tratamentos consistiram de quatro níveis de salinidade da água (1,45; 3,80; 6,08 e 8,48 dS m-1 obtidos pela adição de NaCl à água doce local, de um tratamento controle com essa água doce (0,29 dS m-1 e de um rejeito de osmose reversa (8,39 dS m-1 de um município do semiárido. Foram usadas 36 parcelas experimentais aleatorizadas em seis blocos. Os dados foram analisados mediante análise de variância e de regressão. Houve redução linear da produção de massa de matéria fresca e seca da parte aérea (MFPA e MSPA, com o aumento da salinidade, de 7,86 e 6,76% por acréscimo unitário na condutividade elétrica da água (dS m-1, respectivamente; não ocorreu diferença entre águas isosmóticas de NaCl e rejeito de dessalinização em referência à produção de MFPA. A altura de planta e a taxa de crescimento não indicaram a influência da salinidade no manjericão. As águas salobras não produziram sintomas depreciativos nas plantas.

  17. Crescimento de híbridos e variedades porta-enxerto de citros sob salinidade = Growth of hybrids and rootstock varieties of citrus under salinity.

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    Pedro Dantas Fernandes

    2011-04-01

    Full Text Available A salinidade da água e do solo afeta o crescimento, o desenvolvimento e a produção de espécies frutíferas, dentre as quais os citros. O uso de porta-enxertos tolerantes pode garantir a sustentabilidade do agronegócio citrícola em tais condições. Assim, estudou-se a sensibilidade à salinidade durante a fase de formação de portaenxertoscompreendendo variedades e híbridos selecionados. O experimento foirealizado em casa-de-vegetação, considerando cinco níveis de salinidade da água de irrigação [testemunha, irrigação com água de abastecimento local, condutividade elétrica da água (CEa de 0,41 dS m-1 e água com CEa de 1,0; 2,0; 3,0 e 4,0 dS m-1] e sete genótipos, utilizando delineamento em blocos casualizados, com cinco repetiçõesem esquema fatorial e quatro plantas úteis por parcela, durante o período de 150 dias. Avaliaram-se variáveis de crescimento e fisiológicas. A redução mais expressiva foi observada na fitomassa seca total da parte aérea com aumento unitário da CEa. Observou-se redução linear no crescimento com aumento da salinidade nos híbridosLVK x LVA-009 e TSK x TRENG-256. Dentre os genótipos avaliados, o limoeiro ‘Volkameriano’ foi o menos sensível ao estresse salino.Water and soil salinity affects the growth, development and production of fructiferous species, such as citrus. The use of tolerant rootstocks can guarantee the agribusiness of citrus under such conditions. Thus, the sensibility to salinity during the phase of rootstock formation of varieties and selected hybrids was studied. The experiment was carried out in a greenhouse, with five levels of irrigation water salinity [control, tap water with electrical conductivity (ECw of 0.41 dS m-1, and water with ECw of 1.0, 2.0, 3.0 and 4.0 dS m-1] and seven genotypes, in a randomized block designand five replications each consisting of four plants, during 150 day period. Growth and physiologic variables were evaluated. Significant effects

  18. Arroz e trigo: tolerância à salinidade em solução nutritiva Tolerance of rice and wheat cultivars to salinity

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    José Guilherme de Freitas

    1988-01-01

    Full Text Available O estresse hídrico é uma das principais causas da baixa produtividade de grãos nas culturas de arroz e trigo-de-sequeiro no Brasil. Um programa de melhoramento genético usando um método para selecionar plantas tolerantes ao estresse hídrico diminuiria bastante esses efeitos negativos: por isso, tentou-se verificar os comportamentos de cultivares de arroz (sequeiro e irrigado e trigo sob estresse salino considerando que estes se correlacionassem. Realizaram-se dois experimentos no laboratório da Seção de Arroz e Cereais de Inverno do Instituto Agronômico de Campinas, empregando soluções nutritivas. Os cultivares estudados foram os seguintes: arroz-de-sequeiro: IAC-25, IAC-47, IAC-164, IAC-165, IAC-1246, Batatais, Pérola, Pratão Precoce e Dourado Precoce; de arroz irrigado: IAC-120, IAC-435, IAC-899, IR-841, IAC-1278 e IAC-4440; de trigo: IAC-5, IAS-55, Siete Cerros e Paraguay-281. Tanto o arejamento das soluções como a iluminação das plântulas foram contínuos. Usaram-se as concentrações de cloreto de sódio: 0,0; 0,1; 0,2; 0,3; 0,4; e 0,8 molal (p/m ou potenciais osmóticos de 0,00; -0,47; -0,93; -1,39; -1,85 e -3,75 MPa. As plântulas de arroz cresceram doze dias em solução-tratamento contendo diferentes concentrações de cloreto de sódio em pH 6,0 e com temperatura de raízes 30 ± 1°C. As plântulas de trigo cresceram em dez dias em solução-tratamento em pH 6,0 e temperatura de raízes 25 ± 1°C. Mediu-se o comprimento da maior raiz seminal, comprimento da parte aérea (bainha da terceira folha madura e pesou-se a matéria seca das partes aéreas e raízes, das plantas dos diferentes cultivares estudados. A avaliação da diminuição do diâmetro das raízes e da cor verde foi visual, tanto para o arroz como para o trigo. Os resultados mostraram que o parâmetro da raiz seminal variou mais do que os outros, sendo, portanto, melhor para avaliar a tolerância à salinidade, visando ao melhoramento genético. Assim

  19. Ph3CCOOSnPh3.Ph3PO AND Ph3CCOOSnPh3.Ph3AsO: SYNTHESIS AND INFRARED STUDY

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    ABDOU MBAYE

    2014-08-01

    Full Text Available The mixture of ethanolic solutions of Ph3CCOOSnPh3 and Ph3PO or Ph3AsO gives Ph3CCOOSnPh3.Ph3PO and Ph3CCOOSnPh3.Ph3AsO adducts which have been characterized by infrared spectroscopy. A discrete structure is suggested for both, the environment around the tin centre being trigonal bipyramidal, the triphenylacetate anion behaving as a mondentate ligand.

  20. Ph3CCOOSnPh3.Ph3PO AND Ph3CCOOSnPh3.Ph3AsO: SYNTHESIS AND INFRARED STUDY

    OpenAIRE

    ABDOU MBAYE; ALEXIS BIENVENU BELEKE; CHEIKH ABDOUL KHADIR DIOP; LIBASSE DIOP

    2014-01-01

    The mixture of ethanolic solutions of Ph3CCOOSnPh3 and Ph3PO or Ph3AsO gives Ph3CCOOSnPh3.Ph3PO and Ph3CCOOSnPh3.Ph3AsO adducts which have been characterized by infrared spectroscopy. A discrete structure is suggested for both, the environment around the tin centre being trigonal bipyramidal, the triphenylacetate anion behaving as a mondentate ligand.

  1. EFECTO DE LA SALINIDAD EN LA CONDUCTIVIDAD HIDRÁULICA DE LAS RAÍCES Y LAS RELACIONES HÍDRICAS EN HOJAS DE DOS ESPECIES DE TOMATE (L. esculentum Y L. chessmanii

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    D. Morales

    2003-01-01

    Full Text Available El presente trabajo se realizó con el objetivo de estudiar el comportamiento de la conductividad hidráulica de las raíces y las relaciones hídricas en hojas de dos especies de tomate (Lycopersicon esculentum var. Amalia y Lycopersicon cheesmanii sometidas por períodos cortos a diferentes tratamientos con NaCl en el medio. Las plantas se desarrollaron en macetas con arena sílice introducidas en bandejas en las que se adicionó solución nutritiva de Hoagland. A un grupo de cuatro plantas por tratamiento introducidas en recipientes con la solución nutritiva, a la que se le adicionó NaCl a razón de 0, 25, 50, 75, 100, 150 y 200 mM, se les determinó inmediatamente la conductividad hidráulica de las raíces y a otro grupo de cuatro plantas por tratamiento que permaneció durante 24 horas en solución nutritiva con 0, 100 y 200 mM de NaCl, se les determinó además de la conductividad hidráulica, el potencial hídrico foliar, el potencial osmótico, el potencial de presión (por estimación utilizando la ecuación general del potencial y el potencial osmótico saturado; se estableció la relación entre la conductividad hidráulica y el potencial hídrico foliar. El análisis de los datos indicó una fuerte disminución de la conductividad hidráulica de las raíces de ambas especies, tan pronto se expusieron al tratamiento con solución salina, pero siempre la conductividad fue superior en la especie silvestre, así como las demás variables evaluadas se vieron afectadas por la salinidad y se apreció que a las 24 horas de aplicados los tratamientos, aún no se había producido ajuste osmótico.

  2. Tolerância de bactérias diazotróficas simbióticas à salinidade in vitro Tolerance of diazotrophic symbiotic bacteria to salinity

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    Rafaela Simão Abrahão Nóbrega

    2004-08-01

    Full Text Available A busca de estirpes de bactérias diazotróficas simbióticas tolerantes à salinidade, em conjunto com a seleção de hospedeiros, tem por objetivo aumentar o desempenho da simbiose e manter a produtividade vegetal de forma sustentada em condições de estresse salino. Doze estirpes de bactérias diazotróficas de diferentes procedências foram estudadas quanto à tolerância a diferentes concentrações de NaCl em meios de cultura 79 e LB. As estirpes que apresentaram maior tolerância à salinidade (30 g L-1 em meio 79 foram: BR 6806 e BR 4007, ambas de crescimento rápido isoladas de solos do nordeste brasileiro, UFLA 03-51 e UFLA 03-65, de crescimento rápido e UFLA 03-84, de crescimento lento, sendo as três últimas oriundas da região Amazônica. Essas também estiveram entre as mais tolerantes em meio de cultura LB. A estirpe UFLA 03-84, selecionada em trabalhos prévios por sua alta eficiência para caupi (Vigna unguiculata, pode ser indicada para estudos de inoculação, visando a aumentar o rendimento dessa cultura em solos salinos. Os meios de cultura 79 e LB foram eficientes para avaliar a tolerância relativa de rizóbio a NaCl, mas o meio 79 é mais indicado, pois permite o crescimento de todas as estirpes. Pelos resultados, infere-se haver relação entre tolerância in vitro à salinidade e origem dos microssimbiontes, pois as estirpes BR 4007 e BR 6806, oriundas do Ceará, estiveram entre as mais tolerantes.Tolerance to salinity of diazotrophic bacteriaand their host species could increase plant growth and sustainability in salt stressed soils. Twelve diazotrophic bacteria strains were studied regarding their tolerance to different NaCl concentrations in 79 and LB media. More tolerant (30 g L-1 strains in 79 medium were: the fast growers BR 6806 and BR 4007, isolated from northeast Brazil, UFLA 03-51 and UFLA 03-65, and slow growing strain UFLA03-84, being these last three isolated from Amazon region. These strains were among

  3. Interação entre salinidade e bioestimulante na cultura do feijão caupi Interaction between water salinity and biostimulant in the cowpea plants

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    Francisco de A. de Oliveira

    2013-05-01

    Full Text Available Objetivou-se, neste trabalho, avaliar a interação entre salinidade e o uso de bioestimulante (Stimulate® sobre o desenvolvimento do feijão caupi. A semeadura foi feita em vasos utilizando-se, como substrato, um Argissolo Vermelho Amarelo. O experimento obedeceu a um delineamento inteiramente casualizado em esquema fatorial 2 x 7. Os tratamentos se constituíram da combinação de dois níveis de sais da água de irrigação e seis formas de aplicação de bioestimulante (Ausência, Tratamento de sementes, Foliar aos 20 dias após semeadura (DAS, Foliar aos 40 DAS, Tratamentos de sementes + Foliar aos 20 DAS, Tratamento de sementes + foliar aos 40 DAS e Aplicação foliar aos 20 e 40 DAS. Foram realizadas duas avaliações não destrutivas (20 e 40 DAS e uma destrutiva (60 DAS e avaliados a altura, o número de folhas, a área foliar e a massa seca de folhas, de caule e da parte aérea. Todos os parâmetros fisiológicos avaliados foram afetados pela salinidade. Nas formas de aplicação adotadas o bioestimulante não proporcionou melhorias no desenvolvimento das plantas quando submetidas ao estresse salino; a salinidade inibiu o efeito benéfico do bioestimulante sobre o desenvolvimento do feijão caupi; enfim, o uso de bioestimulante não é viável em plantas cultivadas sob estresse salino.The objective of this study was to evaluate the interaction between salinity levels of the water and the use of biostimulant (Stimulate® in the initial development stage of cowpea plants. The sowing of seeds was done in pots, using as a substrate Alfissol and two plants per pot. The experimental design was completely randomized in a 2 x 7 factorial scheme. The treatments consisted of combination of two salinity levels (0.5 and 5.0 dS m-1 with seven biostimulant application forms (without application, seed treatment, sprinkled 20 days after sowing (DAS, sprinkled 40 DAS, seed treatment + sprinkled 20 DAS, seed treatment + sprinkled 40 DAS and sprinkled

  4. Efeito de liberadores de óxido nítrico na qualidade fisiológica de sementes de repolho sob salinidade

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    Ingrid Schimidt Kaiser

    2016-02-01

    Full Text Available RESUMO Estudos realizados com Brassica sp. demonstram que o estresse salino afeta a qualidade fisiológica e o vigor das sementes. Assim, a busca por substâncias que minimizem os efeitos provocados pelo estresse salino durante a germinação são de grande importância. Objetivou-se com este trabalho avaliar a ação de substâncias liberadoras de óxido nítrico durante a germinação de sementes de repolho cultivado sob condições de salinidade. As sementes foram pré-embebidas em soluções de nitrato de potássio (KNO3 e nitroprus siato de sódio (SNP nas concentrações de zero (controle, 0,01, 0,10, 1,00 e 10,00 mmol L-1, por 30 minutos. Posteriormente, distribuídas sobre papel germitest em placas de Petri, umedecido com solução salina de NaCl nos potenciais de zero, -0,6 e -1,2 MPa. Foram avaliados a germinação, primeira contagem de germinação, índice de velocidade de germinação, tempo médio de germinação, comprimento de parte aérea, comprimento de raiz e massa seca das plântulas. Não houve germinação no potencial osmótico de -1,2 MPa. O potencial de -0,6 MPa reduz a germinação e o desenvolvimento das plântulas de repolho. Os resultados sugerem que houve ação positiva do KNO3 e do SNP na concentração de 0,01 mmol L-1, revertendo o estresse provocado pela salinidade (-0,6 MPa de NaCl.

  5. Nutrição mineral de mudas de pupunheira sob diferentes níveis de salinidade Mineral nutrition of peach palm seedlings under different salinity levels

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    Antonio Rodrigues Fernandes

    2002-11-01

    Full Text Available O potencial produtivo das plantas pode ser afetado por desordens nutricionais, induzidas pelo estresse salino. O objetivo deste trabalho foi estudar a influência de diferentes níveis de salinidade na nutrição mineral de mudas de pupunheira (Bactris gasipaes H.B.K., mediante o uso de solução nutritiva, em casa de vegetação. O experimento foi instalado em blocos ao acaso, com sete tratamentos e quatro repetições. Os tratamentos constaram das seguintes doses (mmol L-1: 0,0 de Na e 0,5 de Cl; 1,0 de Na e 0,5 de Cl (controle; e 5,0, 15,0, 30,0, 60,0 e 120,0 de NaCl. Os teores dos macronutrientes variaram em razão da salinidade, e verificou-se que o P e K apresentaram seus teores reduzidos nas raízes, o K e o Ca, nas folhas e o S, nas diferentes partes, enquanto o Na e o Cl apresentaram teores incrementados nas diferentes partes da planta. As relações Na/K, Na/Ca, Na/Mg, Cl/N, Cl/P e Cl/S aumentaram, causando um desbalanço nutricional na planta.The productive potential of plants may be affected by nutritional disorders induced by saline stress. The objective was to study the influence of different salinity levels on mineral nutrition of peach palm (Bactris gasipaes H.B.K. seedlings in greenhouse conditions with nutritive solution. The experimental design was in randomized blocks, with seven treatments and four replications. The treatments consisted of the following dosages (mmol L-1: 0.0 of Na and 0.5 of Cl; 1.0 of Na and 0.5 of Cl (control; and 5.0, 15.0, 30.0, 60.0 and 120.0 of NaCl. The content of the macronutrients varied with the salinity, there was reduction of P and K in the roots, K and Ca in the leaves, and S in different parts of the plants. Therefore, there was increase of Na and Cl in different parts of the plant. The enhancement of the ratios Na/K, Na/Ca, Na/Mg, Cl/N, Cl/P and Cl/S induced a nutritional imbalance in the plant.

  6. Evolução e variabilidade espacial da salinidade em Neossolo Flúvico cultivado com cenoura sob irrigação Evolution and spatial variability of salinity in a Fluvic Neossol cropped with irrigated carrot

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    Edivan R. de Souza

    2008-12-01

    Full Text Available Desenvolveu-se um experimento de campo com o intuito de verificar o efeito da irrigação por microaspersão, utilizando-se água de condutividade elétrica média de 1,42 dS m-1, sob as propriedades químicas de um Neossolo Flúvico cultivado com cenoura cv. Brasília. A área foi dividida em dois setores (S1 e S2, com 900 m² cada um (30 x 30 m e texturas contrastantes; no S2 adicionou-se cobertura morta aos 23 dias após a semeadura (DAS e se adotou uma fração de lixiviação de 0,20 para os dois setores. Realizaram-se duas amostragens de solo, antes da semeadura e a 96 DAS, nas camadas de 0-20 e 20-40 cm, em 49 pontos no S1 e 52 pontos no S2, segundo uma malha de 5 x 5 m. No extrato da pasta saturada foram medidos o pH e a condutividade elétrica (CEes, e determinadas as bases solúveis; determinou-se, ainda, as bases trocáveis, calculando-se a relação de adsorção de sódio e a percentagem de sódio trocável. Os dados foram analisados por estatística descritiva e geoestatística. Considerando-se a camada de 0-40 cm, a área salina no S1, inicialmente de 7,98%, aumentou para 15,09% ao final do ciclo cultural. Para o S2, a área salina passou de 5,97 para 5,52%; verificou-se, assim, a influência decisiva da textura e da cobertura morta no controle da salinidade do solo.A field experiment was carried out aiming to verify the effect of micro sprinkler irrigation, using water with an average electrical conductivity of 1.42 dS m-1, on the chemical properties of a Fluvic Neossol cropped with carrot, variety Brasília. The area was divided into two sectors (S1 and S2, each one with 900 m² (30 x 30 m and contrasting textures; at S2 mulch was added at day 23 after sowing (DAS. A leaching fraction of 0.20 was adopted for both sectors. Two soil sampling schemes were carried out, before sowing and at 96 DAS, in the 0-20 and 20-40 cm layers, at 49 points in S1 and 52 points in S2, according to a regular 5 x 5 m mesh. In the extract of saturated

  7. Phänomenologie schulischer Langeweile

    OpenAIRE

    Götz, Thomas; Frenzel, Anne C.

    2006-01-01

    Ziel der vorliegenden Studie war eine Identifizierung und Kategorisierung phänomenologischer Aspekte schulischer Langeweile. Hierzu wurden Daten von 50 Gymnasiasten der 9. Jahrgangsstufe (50% weiblich) erhoben. Die auf der Basis von Schüleraussagen generierten Kategorien zur Phänomenologie schulischer Langeweile erwiesen sich als sehr inhaltsheterogen und deuteten auf verschiedene Formen des Langeweileerlebens hin. Es wurden vier Formen schulischer Langeweile identifiziert und bezüglich der D...

  8. ATIVIDADE DE PEROXIDASES (EC 1.11.1.7 E TEOR DE PROLINA EM FEIJOEIRO Phaseolus vulgaris L. CULTIVADO EM CONDIÇÕES DE SALINIDADE

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    C. ROSSI

    1997-09-01

    Full Text Available Alterações nos níveis de prolina e na atividade da peroxidase foram estudadas em folhas e raízes de feijoeiro em função da resposta à salinidade do meio. A atividade da peroxidase (E.C. 1.11.1.7 e o teor de prolina das folhas foi maior do que nas raízes. Os resultados mostraram que a atividade da peroxidase diminuiu, enquanto os teores de prolina aumentaram gradualmente nas plantas cultivadas em meio salino. Ocorreu diminuição do teor de potássio e aumento de sódio nos órgãos analisados, com o aumento da concentração salina.Changes in proline level and peroxidase activity in bean (Phaseolus vulgaris L. cv. carioca leaves and roots were studied in response to salinity conditions. Peroxidase activity of (EC 1.11.1.7 and proline concentration in bean leaves were higher than in roots. The results showed that peroxidase activity decreased while proline levels increased in bean grown in saline conditions. Increasing salinity levels in the nutrient solution were followed by a significant accumulation of sodium in the roots, with a concomitant decline of potassium.

  9. Evolución del desarrollo del color en sistema modelo de composición similar al dulce de leche. Influencia del tiempo de calentamiento y del Ph

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    Analía Rodríguez Blanco

    2013-01-01

    Full Text Available El color es un atributo importante en la elección del producto dulce de leche por parte del consumidor. El mismo se desarrolla en el proceso de elaboración debido principalmente a las reacciones de pardeamiento no enzimático, las cuales se ven influenciadas por varios factores. En este trabajo se evaluó el desarrollo de color, con el tiempo de tratamiento térmico y el pH inicial como variables tecnológicas, en un sistema modelo compuesto de caseinato, lactosa, sacarosa y agua destilada cuya composición fue similar a la del dulce de leche comercial. El estudio del color se realizó utilizando los parámetros de medición de color del sistema CIELAB y el índice de Kubelka Munk (K/S. Con ambos métodos se constató un aumento significativo del dE*ab y del K/S con el tiempo de tratamiento térmico y el pH inicial. Con el sistema CIELAB además se observó una tendencia a disminuir la luminosidad con el tiempo y el aumento del pH inicial, y el aumento de a* con el tiempo.

  10. Effect of the salinity in the e fi science in the use of the water and the production of dry matter in guayabo Efecto de la salinidad en la eficiencia en el uso del agua y la producción de materia seca en guayabo

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    González M Ing. Agr.; Leonardo A.

    2006-09-01

    Full Text Available

    Effect of salinity on water use efficiency and dry matter production of guava plants. To study the salt tolerance of guava cultivars (Psidium guajava I L.cvs RS 980 and Cimpa 00916, the effect os salinity on growth, dry matter production and agronomic water use efficiency were evaluated. Seedlings were grown in a glasshouse experiment in 3-1 post filled with soil in Tunja, Colombia. Plants were exposed to either non-saline (ECe: 1.2 dS.m-1 or saline conditions using 20, 40, 60 and 80 mM NaCl based to air dry soil (ECe: 3.0, 5.4, 7.9 and 10.5 dS.m-1 respectly of a saturated soil extract 3 months after germination. Plants were harvested 7 months after the NaCl exposure. The evapotranspiration rate (cm3, dry matter production (g, agronomic water use efficiency (g1-1 and leaf area (cm2 of both cultivars was reduced by salinity. Dry matter partitioning in roots shoot and leaves and root: shoot ratio based on dry matter were little affected by salinity. In comparison to the control plants, the agronomic water use efficiency was reduced 29.5% in cultivar RS 980 and 10.0% in Cimpa 00196 by 80 mM NaCl; similarly, 80 mM NaCl reduced the total dry matter production 50.8% in RS 980 and 29.8% in Cimpa 00196 in comparison to the control plants. Thus, it appears that RS 980 was more salt-sensitive than Cimpa 00196.

    En plantas de guayaba (Psidium guajava L. cvs. RS 980 y Cimpa 00916 se evaluó el efecto de la salinidad sobre el crecimiento, la producción de materia seca y la eficacia agronómica en el uso del agua. Las plantas se obtuvieron a partir de semilla, crecieron en un invernadero en materas (tres litros y se expusieron a condiciones no salinas (ECe: 1.2 dS.m-1 o salinas mediante la adición de 20; 40; 60 y 80 mM de NaCl con base en suelo seco al aire (ECe:3.0, 5.4, 7.9 y 10.5 dS.m-1

  11. INDUCCIÓN DE RESPUESTAS ADAPTATIVAS EN EL ARROZ (Oryza sativa L. PARA SU CULTIVO EN CONDICIONES DE SALINIDAD MODERADA

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    J. M. Dell'Amico

    2008-01-01

    en un medio moderadamente salino, lo que sería interesante poder constatar mediante el estudio de las respuestas fisiológicas del cultivo, pues la adaptación al medio salino, aunque sea mediante pretratamientos de naturaleza puramente osmótica, implica una mayor acumulación de los iones salinos en los tejidos de las hojas jóvenes, lo que supone un ajuste osmótico mucho más eficaz y una mayor tolerancia a la .

  12. Crescimento do melão Pele de Sapo, em níveis de salinidade e estágio de desenvolvimento da planta Growth of 'Pele de Sapo' muskmelon under salinity levels and development stage of plant

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    Damiana C. de Medeiros

    2012-06-01

    Full Text Available As áreas de cultivo com intensa evaporação, deficiência em drenagem e uso inadequado de fertilizantes, têm aumentado os problemas com a salinidade, prejudicando o rendimento das culturas. O experimento foi conduzido com o objetivo de se avaliar a alocação de massa seca do meloeiro, em função dos diferentes níveis de salinidade da água de irrigação e estágios de desenvolvimento da planta, em Mossoró, RN. O delineamento experimental utilizado foi o de blocos ao acaso, em parcelas subdivididas apresentando, nas parcelas, cinco níveis de salinidade da água de irrigação (0,54, 1,48, 2,02, 3,03 e 3,90 dS m-1 e, nas subparcelas, quatro épocas de coleta de plantas em função dos estágios de seu desenvolvimento (15, 30, 45 e 60 dias após o transplante - DAT correspondendo às fases de crescimento inicial, floração plena, frutificação plena e anterior ao início da colheita, respectivamente, com quatro repetições. Todos os parâmetros de crescimento avaliados foram afetados pela salinidade da água de irrigação. O efeito da salinidade da água sobre a área foliar específica e a massa seca das folhas, foi variável de acordo com a fase de desenvolvimento das plantas. As variáveis mais afetadas pela salinidade da água de irrigação foram a área foliar e a massa seca de frutos, com redução de 28,9 e 24,6%, respectivamente. O maior acúmulo de massa seca no meloeiro Pele de Sapo ocorreu no período entre 30 e 45 dias após o transplantio.The region of Mossoró, RN, Brazil, underwent increasing problems with soil salinity and melon crop yields, mainly in areas with intense evaporation, deficient drainage and inadequate fertilizer use. With this concern, dry mass accumulation in different muskmelon plant organs was evaluated in a trial combining different irrigation water salinity levels and crop growth stages. The experiment was conducted in completely randomized block design with split plot arrangement, having four

  13. Crescimento do meloeiro cultivado sob diferentes níveis de salinidade, com e sem cobertura do solo Growth of muskmelon under different levels of salinity, with and without soil covering

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    José F. de Medeiros

    2007-06-01

    Full Text Available Objetivou-se, neste trabalho, avaliar o crescimento de híbridos de meloeiro submetidos a três níveis de salinidade da água de irrigação, com presença e ausência de cobertura do solo. O experimento foi conduzido na Fazenda São João, em Mossoró, RN. Utilizou-se um esquema fatorial 3 x 2 x 2 em blocos completos casualizados, com quatro repetições. Os fatores foram três níveis de salinidade da água de irrigação, com condutividade elétrica de 1,2, 2,5 e 4,5 dS m-1, dois híbridos, Gold Mine e Trusty, com e sem cobertura de solo, por filme de polietileno dupla face preto-prateado. A área foliar, fitomassa e taxa de crescimento absoluto foram afetadas pela salinidade da água e cobertura do solo, variando com a idade da planta. A cobertura do solo proporcionou maior área foliar e fitomassa das plantas. O híbrido Trusty reduziu a fitomassa apenas quando se utilizou água de maior salinidade. A taxa de crescimento absoluto (TCA foi máxima entre 35 e 45 dias após o plantio e neste período foi reduzida com o aumento da salinidade. As taxas de crescimento relativo (TCR e de assimilação líquida (TAL não foram afetadas pela salinidade da água, cobertura do solo e híbridos.The objective of this work was to evaluate the growth of melon hybrids submitted to three irrigation water salinity levels with and without soil covering. The experiment was conducted at the São João Farm, Mossoró in the State of Rio Grande do Norte, Brazil. The factorial (3 x 2 x 2 scheme was adapted in completely randomized blocks, with four repetitions. The factors were three salinity levels of irrigation water, with electrical conductivity of 1.2, 2.5 and 4.5 dS m-1, two hybrids (Gold Mine and Trusty, with and without soil covering by a film of double face black-silvery polyethylene. The leaf area, dry weight and rate of absolute growth were affected by water salinity and soil covering, varying with plant age. The soil covering provided a larger leaf

  14. Crescimento e tolerância à salinidade em três espécies medicinais do gênero Plectranthus expostas a diferentes níveis de radiação

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    M.A.C. Freitas

    2014-12-01

    Full Text Available No cultivo de plantas medicinais as condições de salinidade e de luz podem exercer influência no rendimento e na qualidade final da produção de biomassa. O objetivo deste trabalho foi avaliar o efeito de diferentes luminosidades e níveis de salinidade na água de irrigação sobre o crescimento e tolerância de três espécies de plantas do gênero Plectranthus. O ensaio foi conduzido em parcelas subsubdivididas com cinco repetições, sendo as parcelas referente ao fator ambiente (pleno sol e telado, as subparcelas aos níveis de salinidade na água de irrigação - CEa (0,7; 1,9; 3,1; 4,3 e 5,5 dS m-1, e as subsubparcelas às três espécies do gênero Plectranthus (P. amboinicus, P. barbatus e P. grandis. As variáveis de resposta foram: índice relativo de clorofila (IRC, área foliar (AF, razão de área foliar (RAF, área foliar específica (AFE, matéria seca da parte aérea (MSPA, matéria seca das raízes (MSR, matéria seca total (MST, relação MSR/MSPA, grau de tolerância à salinidade, e teor dos íons Na+ e K+. O estresse salino reduziu o crescimento das plantas, sendo as maiores reduções observadas nas plantas expostas a pleno sol. A salinidade influenciou a partição de matéria seca, sendo as raízes mais afetadas do que a parte aérea. Com o aumento da CEa houve aumento expressivo no teor foliar de Na+, enquanto o teor de K+ e o IRC foram reduzidos. Entretanto, o acúmulo de Na+ foi menor em P. grandis. Considerando-se a MST, verificou-se que as três espécies se mostraram moderadamente tolerantes à salinidade de até 3,1 dS m-1, exceto P. grandis cultivada em telado, classificada como tolerante. Em relação ao grau de redução na produção MSPA (parte de interesse comercial, poderia se recomendar o cultivo de P. grandis quando a água de irrigação contiver CEa de até 3,1 dS m-1.

  15. Efeitos da lixiviação e salinidade da água sobre um solo salinizado cultivado com beterraba Effects of leaching and water salinity on a saline soil cultivated with sugar beet

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    Paulo A. Ferreira

    2006-09-01

    Full Text Available Os efeitos de cinco lâminas de lixiviação e quatro níveis de salinidade da água de irrigação sobre a salinidade de um Neossolo Flúvico e a produtividade da cultura da beterraba (Beta vulgaris L. foram estudados em lisímetros de drenagem. Os tratamentos foram dispostos em arranjo fatorial com quatro níveis de condutividade elétrica da água de irrigação (1,0, 2,0, 3,0 e 4,0 dS m-1, a 25 °C e cinco lâminas de lixiviação equivalente a 0,25, 0,50, 0,75, 1,00 e 1,25 do volume de poros do solo ou 53, 106, 159, 206 e 248 mm, respectivamente, no delineamento inteiramente casualizado, com quatro repetições. Os componentes avaliados foram a produtividade da cultura e as salinidades no solo e no lixiviado. Os resultados obtidos mostraram incrementos da salinidade no lixiviado com o decréscimo das lâminas de lixiviação. Os maiores índices de salinidade no perfil do solo, ao final do ciclo da cultura, corresponderam aos tratamentos que receberam as menores lâminas de lixiviação e condutividade elétrica da água de irrigação. A produtividade total da beterraba e a produção das raízes com diâmetros maiores que 3, 4, 5, 6 e 7 cm, não foram influenciadas pelos níveis de salinidade da água de irrigação e lâminas de lixiviação.The effects of five leaching depths and four salinity levels of the irrigation water on the salinity of a Neossol Fluvent and the productivity of sugar beet crop were studied using drainage lysimeters. A completely randomized experimental design was used with four replications, the treatments being displayed in a factorial scheme with four electrical conductivity levels of the irrigation water (1.0, 2.0, 3.0 and 4.0 dS m-1 at 25 °C and five leaching depths equivalent to 0.25, 0.50, 0.75, 1.00 and 1.25 of the soil pores volume or 53, 106, 159, 206 e 248 mm, respectively. The crop productivity and the salinity of soil and leachate were evaluated. The results showed increased salinity in the leachate

  16. Tolerância de juvenis do pampo Trachinotus marginatus (Teleostei, Carangidae ao choque agudo de salinidade em laboratório Acute salinity tolerance of juvenile pompano Trachinotus marginatus (Teleostei, Carangidae under laboratory conditions

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    Luís André Sampaio

    2003-08-01

    Full Text Available O pampo Trachinotus marginatus é uma espécie com potencial para piscicultura, mas a sua utilização pode ser limitada pelas variações de salinidade comuns em estuários ou em ambientes super-salinos. Este trabalho foi realizado com o objetivo de determinar a tolerância à salinidade de juvenis de T. marginatus em laboratório. Foram testadas 12 salinidades em duplicata (0, 6, 8, 10, 15, 25, 45, 55, 58, 61, 65 e 75‰ e um tratamento controle (35‰. Dez peixes (comprimento total: 20,7±2,3mm e peso úmido: 427±113mg foram colocados em tanques plásticos de 3L. A temperatura da água foi mantida em 24ºC com um banho termostatisado, aeração constante e, a cada 24 horas, os meios experimentais foram completamente renovados. Após 96 horas de exposição, as salinidades letais médias inferior e superior, com os respectivos intervalos de confiança (IC 95%, foram estimadas em 6,99‰ (IC 95% = 6,86-7,13‰ e 58,50‰ (IC 95% = 56,81-60,24‰, respectivamente. Estes resultados permitem caracterizar esta espécie como eurialina. O estudo da influência da salinidade sobre T. marginatus deve ser aprofundado, buscando avaliar principalmente os efeitos sobre o crescimento, de modo que seja possível determinar o potencial do seu cultivo em ambientes com diferentes salinidades.The pompano Trachinotus marginatus shows good potential for aquaculture, but the success of its culture might be limited by the salinity fluctuations common in estuaries or in hyper-saline environments. The objective of this work was to establish the salinity tolerance of juvenile T. marginatus under laboratory conditions. Twelve salinities (0, 6, 8, 10, 15, 25, 45, 55, 58, 61, 65, and 75‰ plus a control (35‰ were tested in duplicate. Groups of ten fish (total length: 20.7±2,3mm and wet weight: 427±113mg were placed in plastic tanks with 3L of water. A water bath was set to control the temperature at 24ºC, water was continuously aerated, and completely exchanged

  17. Influência do tempo de aclimatação na resposta do cajueiro à salinidade Influence of acclimatization time on response of cashew plant to salinity

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    Jean C. A. Brilhante

    2007-04-01

    Full Text Available A resposta das plantas à salinidade depende de fatores fisiológicos, bioquímicos e genéticos. Com este trabalho, objetivou-se estudar o impacto do tempo de aclimatação à solução nutritiva sobre a resposta do cajueiro à salinidade. Plantas de Anarcadium occidentale L., CCP06, cultivadas em vermiculita durante 28 dias, foram transferidas para solução nutritiva de Hoagland com 1/10 de sua força iônica, onde permaneceram por 1 e 7 dias. Ao final dos dois tempos, a solução nutritiva foi suplementada com 200 mM de NaCl, condições em que as plantas foram cultivadas por 0, 12, 24, 48 e 72 h. As plantas aclimatadas por 7 dias á solução de Hoagland apresentaram sinais fisiológicos mais compatíveis com a tolerância ao NaCl, como menor acumulação de Na+ e, também, menores danos nas membranas, peroxidação dos lipídeos, degradação de proteínas, acumulação de aminoácidos livres e acumulação de prolina. A amônia livre foi o melhor indicador da intensidade do estresse salino. Os danos de membranas aumentaram com a acumulação de Na+ nas folhas. Os resultados evidenciam que o tempo de aclimatação das raízes à solução nutritiva influencia a expressão de fatores capazes de atenuar os efeitos do estresse salino.The plant response to salinity depends on physiological, biochemical and genetic factors and on their interaction with external environment. This work aimed to study the impact of adaptation time in nutrient solution on the cashew response to salinity. Seedlings of Anacardium occidentale L (CCP06 grown in vermiculite, for 28 days, were placed to grow in 1/10 ionic strength Hoagland solution for 1 and 7 days. At the end of each time the solution was supplemented with 200 mM NaCl, and under this condition the plants were monitored for 0, 12, 24, 48 and 72 h. The 7 days Hoagland solution acclimated plants had physiological index more compatible to tolerance to NaCl such as low Na+ accumulation and also low membrane

  18. Efecto de la salinidad sobre la fisiología energética del camarón blanco Litopenaeus vannamei (Boone Effect of salinity on physiological energetics of white shrimp Litopenaeus vannamei (Boone

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    Gustavo Valdez

    2008-08-01

    Full Text Available Se determinó el balance energético en juveniles de Litopenaeus vannamei, aclimatados a la salinidad como hiperosmóticos (20 ups, isosmóticos (26 ups, o hiposmóticos (32 ups. Además, se calculó la razón atómica O:N. La tasa de ingestión, el consumo de oxígeno, la excreción de amonio y el campo de crecimiento fueron afectados significativamente (p 0.05 en los camarones expuestos a las tres salinidades. Para optimizar las condiciones de cultivo de Litopenaeus vannamei se recomienda mantener a los juveniles en la salinidad para la cual es isosmótico (26 ups, evitando el estrés ambiental, lo que desde el punto de vista fisiológico se canaliza en una mayor cantidad de energía hacia el campo de crecimiento.The energy balance was determined with in Litopenaeus vannamei, juveniles acclimated to salinity where they were hyperosmotic (20 ups, isosmotic (26 ups, and hypo-osmotic (32 ups. Also O:N atomic ratio was calculated. The ingestion rate, oxygen consumption, ammonium excretion and scope for growth were affected significantly (p 0.05 in the shrimps exposed to the three salinities. We recommend maintaining Litopenaeus vannamei juveniles at the salinity level which is isosmotic (26 ups, where they are free of environmental stress, these conditions for white shrimp juveniles would enhance production in the cultivation of this species.

  19. Efecto del aumento de salinidad en la fertilización de óvulos de erizos Strongylocentrotus franciscanus y Lytechinus anamesus Effect of increased salinity in the ovum fertilization of sea urchin Strongylocentrotus franciscanus and Lytechinus anamesus

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    B. Estela López-Ortiz

    2009-08-01

    Full Text Available Se evaluaron los efectos del incremento de salinidad sobre la fertilización de óvulos de erizos de mar de las especies Strongylocentrotus franciscanus Agassiz, 1863 y Lytechinus anamesus Clark, 1912, los cuales fueron colectados mediante buceo libre en la bahía de Todos Santos, Ensenada, B. C., México. La fertilización de los óvulos de cada especie de erizo se llevó a cabo en un intervalo de salinidad de 33.4 a 53.4‰, estimándose para cada caso su CL50. Los resultados indicaron que la capacidad de fertilización de los gametos disminuye conforme la salinidad se incrementa, alcanzando la CL50 en las 43.4‰ para Strongylocentrotus franciscanus y 48.4‰ para Lytechinus anamesus, confirmando estudios previos que recomiendan no exceder las 40‰ para evitar efectos adversos en los ciclos de vida de la fauna marina.The effects of increased salinity were evaluated on the ovum fertilization of the sea urchin species, Strongylocentrotus franciscanus Agassiz, 1863 and Lytechinus anamesus Clark, 1912, which were collected by means free-diving in the bay Todos Santos, Ensenada, B. C., Mexico. The ovum fertilization of each species of sea urchin was estimated using a range of salinity from 33.4 to 53.4‰, being considered for each case its LC50. The results indicated that the capacity of fertilization of gametes decrease as the salinity increases, reaching the LC50 at 43.4‰ for Strongylocentrotus franciscanus and 48.4‰ for Lytechinus anamesus, confirming previous research that recommended not exceed 40‰ to avoid adverse effects in life cycles of the marine fauna.

  20. Estabilidade temporal da potenciometria e da salinidade em vale aluvial no semiárido de Pernambuco Temporal stability of piezometric levels and salinity in an alluvial valley in the semiarid Pernambuco - Brazil

    OpenAIRE

    Robertson V. P. Fontes Júnior; Montenegro, Abelardo A. A.; Suzana M. G. L. Montenegro; Thais E. M. dos Santos

    2012-01-01

    As restrições no uso e na disponibilidade das águas subterrâneas nos aluviões do semiárido nordestino estão diretamente ligadas à sazonalidade e à variabilidade espacial de seus níveis potenciométricos e salinidade. A estabilidade temporal é de grande interesse, por facilitar o monitoramento, possibilitando se obter locais representativos acerca da área em estudo, constituindo-se em uma importante ferramenta para a gestão dos recursos hídricos subterrâneos. Com isto, o objetivo deste trabalho...

  1. Influência de diferentes níveis de salinidade nas características sensoriais do tomate Influence of different levels of salinity on sensory characteristics of tomato

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    Waleska M. Eloi

    2011-01-01

    Full Text Available Objetivou-se, com este trabalho, avaliar o efeito de diferentes níveis de salinidade no solo provocados pelo uso da fertirrigação, nas características sensoriais de frutos do tomateiro. O experimento foi conduzido em duas etapas, a primeira desenvolvida em laboratório e a segunda realizada em estufa plástica. A primeira etapa consistiu de testes preliminares que possibilitaram a construção de curvas artificiais de salinização, visando à realização do processo de salinização artificial do solo; na segunda etapa estudou-se a evolução dos diferentes níveis iniciais de salinidade do solo, implementados por meio da aplicação de fertilizantes, de acordo com a marcha de absorção de nutrientes pela cultura. Os níveis iniciais de salinidade utilizados foram: 1,5; 2,5; 3,5; 4,5; 5,5 e 6,5 dS m-1. Para a análise sensorial dos frutos realizou-se o teste hedônico com 39 provadores. Verificou-se que os índices de salinidade utilizados não interferiram na aceitação do produto.With the objective of evaluating the effect of different salinity levels in the soil provoked by the use of fertigation, on the sensory characteristics of tomato fruits, an experiment was conducted in two stages, being the first developed in laboratory and the second one accomplished in plastic greenhouse. The first stage consisted of preliminary tests that made possible the construction of artificial curves of salinization, seeking accomplishment of the process of artificial salinization of the soil. In the second stage the evolution of the different initial levels of soil salinity was studied, implemented through the application of fertilizers in agreement with the absorption of nutrients for the crop. The levels of salinity used were: 1.5, 2.5, 3.5, 4.5, 5.5 and 6.5 dS m-1. For the fruit sensory analysis the hedonic test with 39 individuals was performed. It was found that the levels of salinity used did not interfer in the acceptance of the product.

  2. Produção de muda de maracujazeiro amarello submetidas ã salinidade em solo como biofertilizante bovino Effect of saline irrigation waters and bovine biofertilizer application on the production of yellow passionfruit seedling

    OpenAIRE

    Francisco de Oliveira Mesquita; Lourival Ferreira Cavalcante; Walter Esfrain Pereira; Alex heus Rebequi; Antonio João de Lima Neto; Járisson Cavalcante Nunes

    2012-01-01

    O experimento foi desenvolvido em abrigo protegido no período de 1 de maio a 31 de julho de 2008, no município de Areia, estado da Paraíba, PB, Brasil, com objetivo de estudar os efeitos da salinidade da água de irrigação sobre o comportamento inicial de mudas de maracujazeiro amarelo em substrato não salino com e sem biofertilizante bovino. Os tratamentos foram distribuídos no delineamento inteiramente casualizado, com três repetições e doze plantas por parcela, em arranjo fatorial 5 x 2 x 2...

  3. Interação entre salinidade e biofertilizante bovino na cultura do feijão-de-corda Interaction between water salinity and bovine biofertilizer on the cowpea plants

    OpenAIRE

    Francisco L. B. da Silva; Lacerda, Claudivan F.; Geocleber G. de Sousa; Antônia L. R. Neves; Giovana L. da Silva; Carlos H. C. Sousa

    2011-01-01

    Objetivou-se avaliar a interação entre salinidade e o uso de biofertilizante bovino sobre a condutividade elétrica do solo, crescimento inicial, trocas gasosas e teores de elementos minerais no feijão-de-corda. O experimento foi conduzido em ambiente protegido do Departamento de Ciências dos Solos - UFC. A semeadura foi feita em vasos, utilizando-se, como substrato, um Argissolo Vermelho Amarelo. O experimento obedeceu a um delineamento inteiramente casualizado, em esquema fatorial 5 x 2, ref...

  4. Variaciones en el pH de la rizosfera y en el porcentaje de materia seca de Vicia sativa al aplicar dos fuentes fosfatadas de baja solubilidad en un andisol del departamento de Nariño, Colombia

    OpenAIRE

    Menjivar F Juan Carlos; Castillo F. Jesús; Vélez L. Jorge; Arteaga M Germán

    2006-01-01

    En el estudio se utilizaron seis tratamientos: el testigo (T0), sin fuentes fosfatadas (T1) y con adiciones de 25 y 50 kg/ha de P como fosforita Huila (T2 y T3) y calfós (T4 y T5). Los cambios generados por la raíz se evaluaron utilizando la solución nutritiva de Marschner Römheld y Ossenberg-Neuhaus, acondicionada con agar. El porcentaje de materia seca parcial de Vicia sativa se incrementó significativamente al aplicar 25 y 50 kg/ha de P como fos...

  5. PH og modernismen

    DEFF Research Database (Denmark)

    Ahnfeldt-Mollerup, Merete

    2012-01-01

    Artiklen kaster et kritisk blik på Poul Henningsens samfundsanalyse og dennes sammenhæng med hans design. PH ses i en bredere national og international sammenhæng. Diskussion af designmetoder, æstetik og Bauhaus.......Artiklen kaster et kritisk blik på Poul Henningsens samfundsanalyse og dennes sammenhæng med hans design. PH ses i en bredere national og international sammenhæng. Diskussion af designmetoder, æstetik og Bauhaus....

  6. Hydrodeoxygenation of Phenolic Compounds by Sulfided (CoMo/Al2O3 Catalysts, a Combined Experimental and Theoretical Study Hydrodésoxygénation de composés phénoliques en présence de catalyseurs sulfurés (CoMo/Al2O3 : une étude expérimentale et théorique

    Directory of Open Access Journals (Sweden)

    Badawi M.

    2013-04-01

    Full Text Available The hydrodeoxygenation of model phenol compounds (phenol and 2-ethylphenol was carried over unpromoted Mo/Al2O3 and promoted CoMo/Al2O3 catalysts. Hydrodeoxygenation proceeds by two pathways: – hydrogenation of the aromatic ring followed by Csp3-O bond cleavage (HYD pathway, (hydrogenation of the aromatic ring followed by Csp3-O bond cleavage; – direct cleavage of the Csp2-O bond (DDO pathway. Both routes were favored by the presence of Co on the catalyst, while the presence of the alkyl substituent on the phenolic ring favors the DDO route but inhibits the HYD pathway. IR (InfraRed spectroscopy shows that while phenol mostly dissociates on these catalysts, a significant fraction of 2-ethylphenol remains non dissociated. The adsorption energies of both reactants and possible reaction intermediates on promoted and non-promoted sulfide phases as computed by DFT (Density-Functional Theory confirm these findings and allow rationalizing the catalytic activity trends observed experimentally. L’hydrodésoxygénation de deux composés phénoliques modèles (phénol et 2-éthylphénol a été étudiée sur deux catalyseurs Mo/Al2O3 et CoMo/Al2O3 sulfurés. La désoxygénation de ces molécules fait intervenir deux voies parallèles et indépendantes, à savoir : – l’hydrogénation du noyau aromatique suivie par la rupture de la liaison Csp3-O (voie HYD, (hydrogenation of the aromatic ring followed by Csp3-O bond cleavage; – la rupture directe de la liaison Csp2-O (voie de DésOxygénation Directe – DOD. Ces deux voies sont favorisées en présence du catalyseur promu par le cobalt (CoMo/Al2O3. La présence du groupe éthyle permet d’améliorer la voie DOD mais conduit à une diminution de la voie HYD. Les études menées par spectroscopie IR (InfraRouge montrent que le phénol est majoritairement dissocié sur ces catalyseurs alors que le 2-éthylphénol semble plutôt adsorbé de façon non-dissociative. Les énergies d’adsorption de

  7. ATIVIDADE DE PEROXIDASES (EC 1.11.1.7 E TEOR DE PROLINA NO EMBRIÃO E COTILÉDONES DE FEIJOEIRO Phaseolus vulgaris L. EM CONDIÇÕES DE SALINIDADE

    Directory of Open Access Journals (Sweden)

    G.P.P. LIMA

    1997-09-01

    Full Text Available Os efeitos da salinidade sobre a atividade de peroxidases foram acompanhadas no embrião e em cotilédones de feijoeiro Phaseolus vulgaris L. cv. Carioca, observando-se em ambos, aumento na atividade das enzimas. Com relação ao teor de prolina, ocorreu decréscimo constante no embrião de feijoeiro cultivado em condições salinas, entretanto, nos cotilédones, verificou-se aumento progressivo em condições de presença ou ausência de salinidade.Changes in proline level and peroxidase activity in bean embryo and cotiledon were studied in response to salinity conditions. Activity of peroxidases (EC 1.11.1.7 in bean embryo and cotiledon (Phaseolus vulgaris L. cv. Carioca was higher than in seedlings growing in the absence of NaCl. Proline level decresead constantly in bean embryo growing in saline conditions. However, in cotiledon the proline content increased progressively in the absence and presence of NaCl in growth solution.

  8. Ph interno en geles de polivinilimidazol

    OpenAIRE

    Rupérez Arroyo, Manuel

    2011-01-01

    En el presente trabajo se ha establecido un método para medir el pH en el interior de hidrogeles hinchados de poli(N‐vinilimidazol) a través de las variaciones en el tiempo de vida de una sonda fluorescente sensible al pH. Se han contrastado el modelo teórico de hinchamiento y los estudios precedentes sobre este tipo de hidrogeles con nuestras observaciones, encontrando en este método de caracterización fotofísica una herramienta útil y prometedora, a pesar de que la sonda fluorescente escogi...

  9. Plant Habitat (PH)

    Science.gov (United States)

    Onate, Bryan

    2016-01-01

    The International Space Station (ISS) will soon have a platform for conducting fundamental research of Large Plants. Plant Habitat (PH) is designed to be a fully controllable environment for high-quality plant physiological research. PH will control light quality, level, and timing, temperature, CO2, relative humidity, and irrigation, while scrubbing ethylene. Additional capabilities include leaf temperature and root zone moisture and oxygen sensing. The light cap will have red (630 nm), blue (450 nm), green (525 nm), far red (730 nm) and broad spectrum white LEDs. There will be several internal cameras (visible and IR) to monitor and record plant growth and operations.

  10. MRF with adjustable pH

    Science.gov (United States)

    Jacobs, Stephen D.

    2011-10-01

    Deterministic final polishing of high precision optics using sub-aperture processing with magnetorheological finishing (MRF) is an accepted practice throughout the world. A wide variety of materials can be successfully worked with aqueous (pH 10), magnetorheological (MR) fluids, using magnetic carbonyl iron (CI) and either ceria or nanodiamond nonmagnetic abrasives. Polycrystalline materials like zinc sulfide (ZnS) and zinc selenide (ZnSe) are difficult to polish at pH 10 with MRF, due to their grain size and the relatively low stiffness of the MR fluid lap. If microns of material are removed, the grain structure of the material begins to appear. In 2005, Kozhinova et al. (Appl. Opt. 44 4671-4677) demonstrated that lowering pH could improve MRF of ZnS. However, magnetic CI particle corrosion rendered their low pH approach unstable and unsuitable for commercial implementation. In 2009, Shafrir et al. described a sol-gel coating process for manufacturing a zirconia-coated CI particle that protects the magnetic core from aqueous corrosion (Appl. Opt .48 6797-6810). The coating process produces free nanozirconia polishing abrasives during the coating procedure, thereby creating an MR polishing powder that is "self-charged" with the polishing abrasive. By simply adding water, it was possible to polish optical glasses and ceramics with good stability at pH 8 for three weeks. The development of a corrosion resistant, MR polishing powder, opens up the possibility for polishing additional materials, wherein the pH may be adjusted to optimize effectiveness. In this paper we describe the CI coating process, the characterization of the coated powder, and procedures for making stable MR fluids with adjustable pH, giving polishing results for a variety of optical glasses and crystalline ceramics.

  11. Production and quality of melon hybrid Mandacaru irrigated with different levels of salinity Produção e qualidade de melão híbrido Mandacaru irrigado com diferentes níveis de salinidade

    Directory of Open Access Journals (Sweden)

    Damiana Cleuma de Medeiros

    2011-12-01

    Full Text Available Among the problems faced by the melon crop in the state of Rio Grande do Norte, northeastern Brazil, the effect of water and soil salinity is considered one of the key factors to limit fruit production and quality. The aim of this work was to study the effects of using irrigation waters with different salinity levels on yield and quality of fruits of the yellow melon hybrid Mandacaru. A randomized complete block design was used with five treatments (irrigation water salt concentrations: 0.54, 1.48, 2.02, 3.03, 3.9 dS m-1 and four replications. The effects of these concentrations were evaluated through, number of marketable fruits per plant, marketable and total fruit yield, average marketable fruit mass, soluble solids content and pulp firmness. Increment in water salinity level negatively influenced crop yield. The 3.9 dS m-1 salinity level caused yield losses of 20.31%, due to the reduction of fruit number per plant. The highest soluble solid content and the highest pulp firmness values were estimated to occur at salinity levels 2.09 and 3.5 dS m-1, respectively.Dentre os problemas enfrentados pela cultura do melão no estado do Rio Grande do Norte, a salinidade da água e do solo é considerada um dos principais fatores que limitam a produção e a qualidade dos frutos. O objetivo do trabalho foi estudar os efeitos de aplicação de águas de irrigação com diferentes níveis de salinidade na produção e qualidade do melão Amarelo híbrido Mandacaru. O delineamento utilizado foi de blocos completos casualizados com quatro repetições. Os tratamentos constaram de concentrações de sais na água de irrigação (0,54; 1,48; 2,02; 3,03; 3,9 dS m-1. As características avaliadas de produção e qualidade foram: produtividade total e comercial, número de frutos comerciais por planta, massa média de frutos comerciais, sólidos solúveis (SS e firmeza de polpa. O incremento do nível de salinidade da água influenciou negativamente o

  12. Salinity tolerance of halophyte Atriplex nummularia L. grown under increasing NaCl levels Tolerância à salinidade da halófita Atriplex nummularia L. cultivada em níveis crescentes de NaCl

    Directory of Open Access Journals (Sweden)

    Sandro A.M. de Araújo

    2006-12-01

    Full Text Available The current study reports effects of salt stress on growth, K+ nutrition and organic composition of Atriplex nummularia. The upper limit of the NaCl gradient imposed on the plants was close to seawater salinity (600 mM. An external NaCl of 150 mM improved the growth of this species, which corroborates its halophytic nature. Evidence show that Atriplex nummularia was responsive to NaCl, but the mechanisms of this response are still not known. In such stress condition, Na+ and Cl- accumulation in leaves was far greater than that in roots; therefore salinity tolerance of Atriplex nummularia is not due to ion exclusion mechanism. In spite of a reduction of K+ content of tissues under salinity conditions, no corresponding physiological relevance of this in terms of growth was found. The high affinity of root cells for Na+ during uptake and, probably, its subsequent sequestration into cell vacuoles and structures of protection seems to contribute to osmotic adjustment as an increase in relative water content (RWC of leaves was observed. NaCl caused a decrease in total soluble proteins and chlorophylls; the relevance of this is discussed in terms of mechanisms of salinity tolerance. The ability of Atriplex nummularia plants to keep Na+ and Cl- away from enzymes and cytosolic structures, together with an effective osmotic adjustment, is suggested as having a role in its tolerance to high salinity.O presente estudo relata os efeitos do estresse salino no crescimento, na nutrição de K+ e na composição orgânica de Atriplex nummularia. A maior concentração de NaCl imposta às plantas foi similar a da salinidade da água do mar (600 mM. Uma concentração externa de 150 mM de NaCl estimulou o crescimento da espécie o que, em parte, explica seu caráter halofítico. As evidências mostram que a Atriplex nummularia foi receptiva ao NaCl, porém os mecanismos envolvidos são ainda esperados. Em tais condições de estresse a acumulação de Na+ e Cl

  13. Efeito da nutrição de nitrato na tolerância de plantas de sorgo sudão à salinidade Effect of nitrate nutrition on tolerance of sudangrass plants to salinity

    Directory of Open Access Journals (Sweden)

    Alexcyane Rodrigues Feijão

    2011-09-01

    Full Text Available O objetivo deste trabalho foi estudar o efeito da nutrição de NO3- no crescimento, nas trocas gasosas e no acúmulo de solutos inorgânicos e orgânicos em plantas de sorgo sudão submetidas à salinidade. As plantas foram cultivadas em meio hidropônico e mantidas em casa de vegetação. O delineamento experimental foi o inteiramente casualizado, em esquema fatorial 2 (NO3- a 0,5 mM ou 8,0 mM x 2 (NaCl a 0 mM ou 100 mM, com cinco repetições. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey a 5% de significância. A salinidade reduziu a área foliar e a massa seca da parte aérea e das raízes, sendo as plantas nutridas com NO3- a 8,0 mM menos afetadas que aquelas com NO3- a 0,5 mM. A condutância estomática, a fotossíntese, a transpiração e a relação entre a concentração interna e externa de CO2 foram aumentadas pela melhor nutrição de NO3-. Os teores de Na+ e Cl- foram significativamente aumentados pela salinidade em folhas e em raízes e os de K+ foram reduzidos apenas nas raízes. Apesar disso, as plantas nutridas com NO3- a 8,0 mM apresentaram os menores teores de Na+ e Cl- nas folhas sob estresse salino. A salinidade aumentou os teores de prolina e N-aminossolúveis e a maior concentração de NO3- no meio favoreceu o acúmulo desses solutos nas raízes de plantas estressadas. Uma adequada nutrição com NO3- foi capaz de reduzir os efeitos deletérios da salinidade nas plantas de sorgo sudão.This work aimed to study the effect of NO3- nutrition on growth, on gas exchange and on inorganic and organic solutes accumulation of sudangrass plants subjected to salinity. Plants were grown in hydroponic medium and kept in a greenhouse. The experiment was a completely randomized design, following a factorial arrangement of 2 (NO3- at 0,5 mM or 8,0 mM x 2 (NaCl at 0 mM or 100 mM, with five replications. All data were subjected to analysis of variance and the means were compared by Tukey

  14. Interação entre salinidade e biofertilizante bovino na cultura do feijão-de-corda Interaction between water salinity and bovine biofertilizer on the cowpea plants

    Directory of Open Access Journals (Sweden)

    Francisco L. B. da Silva

    2011-04-01

    Full Text Available Objetivou-se avaliar a interação entre salinidade e o uso de biofertilizante bovino sobre a condutividade elétrica do solo, crescimento inicial, trocas gasosas e teores de elementos minerais no feijão-de-corda. O experimento foi conduzido em ambiente protegido do Departamento de Ciências dos Solos - UFC. A semeadura foi feita em vasos, utilizando-se, como substrato, um Argissolo Vermelho Amarelo. O experimento obedeceu a um delineamento inteiramente casualizado, em esquema fatorial 5 x 2, referente a cinco níveis de sais da água de irrigação e dois de biofertilizante bovino. O aumento dos níveis salinos da água de irrigação inibiu o crescimento inicial das plantas, sendo menos afetado no solo com o biofertilizante. O aumento da salinidade da água aliado à aplicação do biofertilizante, resultou no aumento da salinidade do solo. O aumento do teor salino da água de irrigação provocou redução nas trocas gasosas, mas em menor proporção nas plantas desenvolvidas nos tratamentos com o biofertilizante. A extração dos elementos essenciais e de sódio obedeceu a seguinte ordem: Ca > K > Na > P. A aplicação de biofertilizante bovino foi eficiente ao aumentar os teores de P na planta e de aumentar os totais extraídos de K, P e Ca, independente no nível de salinidade aplicado. Entretanto, os efeitos benéficos da aplicação de biofertilizante bovino sobre o crescimento, trocas gasosas e extração de nutrientes, são menos expressivos nos maiores níveis de salinidade da água de irrigação.The objective of this study was to evaluate the interaction between salinity levels of the water and the use of biofertilizer soil electrical conductivity of soil, initial growth, gas exchange and mineral content in cowpea plants. The experiment was performed conducted under greenhouse of the Department of Soil Science - UFC. The sowing of seeds was done in pots, using as a substrate Alfissol and two plants per pot. The experimental design

  15. Tolerância à salinidade em feijão (Phaseolus vulgaris L Salt tolerance in bean (Paseolus vulgaris cell culture

    Directory of Open Access Journals (Sweden)

    F. Broetto

    1995-04-01

    Full Text Available Uma das aplicações das técnicas da cultura de tecidos no melhoramento é a identificação de linhas de células que apresentam tolerância à salinidade. Vários autores obtiveram linhas de células tolerantes ao estresse salino; e estudo de mecanismos bioquímicos da tolerância a sais em plantas tem demonstrado altas correlações entre estes e o acúmulo de macromoléculas em tecido de plantas superiores. Para verificar essas correlações em feijão (Phaseolus vulgaris cv IAC carioca, calos oriundos de eixos embrionários foram cultivados em meio sólido, suplementado com NaCl nas concentrações de 0 a 60 mM. Após 13 dias de incubação, os calos foram coletados e analisados quanto ao crescimento relativo, teor de proteínas, teor de prolina e atividade da peroxidase. Os parâmetros analisados mostraram decréscimo no crescimento relativo e no de proteínas em resposta ao NaCl. Paralelamente, observou-se aumento significativo no conteúdo de prolina e atividade da enzima peroxidase.One of the applications of the tissue culture technique in plant improvement is the identification of cell lines which show salinity tolerance. Several authors were able to obtain saline stress-tolerant cell lines and show that mechanisms of tolerance to salts have a strong correlation between this phenomenon and a high macromolecule concentration in plant tissues. Callus obtained from embrionic axis of Phaseolus vulgarís cv. IAC carioca in solid medium, supplemented with 0 to 60 mM NaCl, as the salt treatment, were used. Callus harvesting was done on the 13th day, when they were processed for relative growth, protein, proline content and peroxidase acivity. The results show both, a decrease of the relative growth and of protein content in response to the NaCl treatment, as compared to controls. However, there was a significant increase on the proline content and on the peroxidase activity.

  16. Ph.D. shortage

    Science.gov (United States)

    The late 1990s will see a shortage of Ph.D. graduates, according to the Association of American Universities, Washington, D.C. AAU's new comprehensive study, “The Ph.D. Shortage: The Federal Role,” reports that competition for new Ph.D.s is already intense and can only intensify because demand is greater than supply in both academic and nonacademic markets.Doctoral education plays an increasingly important role in U.S. research and development programs. Students have a pivotal part in doing research and enriching it with new ideas. The AAU report says that graduate students are “major determinants of the creativity and productivity of U.S. academic research, the source of more than 50% of the nation's basic research.’ The market for doctoral education extends beyond the university. In 1985, about 43% of all Ph.D.s employed in this country were working outside higher education; the demand for doctorate recipients in nonacademic sectors continues to grow.

  17. Tolerance to salinity of chicory plants grown in hydroponics Tolerância do almeirão à salinidade em cultivo hidropônico

    Directory of Open Access Journals (Sweden)

    Jerônimo Luiz Andriolo

    2008-08-01

    Full Text Available Chicory plants, cv. 'Amarelo' and 'Pão de Açúcar', were grown hydroponically under four NaCl concentrations in the nutrient solution to determine its tolerance to salinity. Sowing was made in rows placed 0.05m apart, on a 0.15m deep sand growing bed placed over fibber cement tiles. After emergence, plants were thinned to a plant density of 1,600plants m-2. A standard nutrient solution was used, with the main composition of, in mmol L-1, 13.5 NO3-; 2.5 NH4+; 1.5 H2PO4-; 1.5 SO4--; 7.5 Ca++; 10.0 K+ and 1.5 Mg++. The control (T1 was the standard nutrient solution, without addition of NaCl. Four salinity levels were compared, by adding 0.697 (T2, 1.627 (T3, 2.556 (T4 and 3.485 (T5g L-1 of NaCl. The nutrient solution was delivered to plants four times a day, in a closed system. A completely split plot randomised experimental design was used, with four replications. Plants were harvested at 31 days after sowing, by cutting the shoot at 0.02m height. Fresh and dry mass of both cultivars decreased linearly by effect of salinity. For similar values of electrical conductivity, the decrease in fresh mass was stronger in plants of the Amarelo cultivar. Adding NaCl to the nutrient solution is a technique that may be used to reduce the water content of chicory plants grown hydroponically.Quatro concentrações de NaCl na solução nutritiva foram empregadas para determinar a tolerância das cultivares de almeirão "Amarelo" e "Pão de Açúcar" à salinidade da solução nutritiva. A semeadura foi feita em fileiras distanciadas de 0,05m, em uma camada de areia de 0,15m de profundidade, distribuída sobre telhas de fibrocimento. Após a emergência foi efetuado o desbaste, mantendo-se uma densidade de 1.600plantas m-2. Foi empregada uma solução nutritiva com a composição de, em mmol L-1, 13,5 NO3-; 2,5 NH4+; 1,5 H2PO4-; 1,5 SO4--; 7,5 Ca++; 10,0 K+ e 1,5 Mg++. A testemunha (T1 foi a solução nutritiva descrita anteriormente, sem adição de Na

  18. Sensing pH with TMCs.

    Science.gov (United States)

    Spalthoff, Christian; Göpfert, Martin C

    2016-07-01

    Transmembrane channel-like (TMC) proteins have been implicated in hair cell mechanotransduction, Drosophila proprioception, and sodium sensing in the nematode C. elegans. In this issue of Neuron, Wang et al. (2016) report that C. elegans TMC-1 mediates nociceptor responses to high pH, not sodium, allowing the nematode to avoid strongly alkaline environments in which most animals cannot survive. PMID:27387645

  19. Low pH Cements

    Energy Technology Data Exchange (ETDEWEB)

    Savage, David; Benbow, Steven [Quintessa Ltd., Henley-on-Thames (United Kingdom)

    2007-05-15

    speciation of silicon at pH 10 has a significant impact upon the solubility of montmorillonite and would thus constitute a logical choice of pH limit for cement-derived pore fluids, but it is unlikely that cement-based grouts could be developed to meet this limit. Control of mass transport by diffusion processes serves as a significant constraint over the amount of bentonite that can be degraded. Computer simulations indicate that porosity reduction is likely at the interface between cement and bentonite. However, it is not clear how the transport properties of bentonite may be modified due to mineral alteration processes. There are considerable uncertainties concerning the precise mechanism of the rate of montmorillonite dissolution at elevated pH. The rate of dissolution may be inhibited by the presence of dissolved Si (and perhaps Al), but this mechanism has yet to be confirmed at high pH. The type of secondary minerals assumed to form from cement-bentonite interaction will also have a significant impact upon the rate of montmorillonite dissolution. Low-pH cement systems have received little attention thus far regarding the development of models for the chemical evolution of pore fluids. Low Ca/Si CSH gels show preferential leaching of Si, which is in marked contrast with gels of greater Ca/Si ratio. Models apparently capable of predicting pore fluid composition coexisting with low Ca/Si CSH gels are a modified Berner model and a solid-solution model proposed by Sugiyama and Fujita. The solubility of silica in pore fluids coexisting with low Ca/Si gels may exceed that of amorphous silica, and may pose problems regarding the stability of montmorillonite in relation to framework silicates such as feldspars. However, the potential rate of conversion of montmorillonite to feldspar under repository conditions is uncertain. It is necessary to use additives such as super plasticiser to improve the workability of low-pH cements. These organic additives have the potential to

  20. Influência da matéria orgânica e do ambiente no crescimento e acúmulo de solutos em Morinda citrifolia submetida à salinidade

    Directory of Open Access Journals (Sweden)

    Maria Cristina Martins Ribeiro de Souza

    2014-09-01

    Full Text Available O Noni (Morinda citrifolia L. é uma planta tolerante aos efeitos salinos e alcalinos dos solos e desenvolve-se em regiões de clima seco ou úmido. Apesar da adaptabilidade intercontinental, ainda são poucas as informações sobre sua tolerância aos sais no solo brasileiro. Baseado no exposto, objetivou-se com o presente trabalho avaliar os efeitos da água salina no crescimento inicial do Noni. Para isso, foi conduzido um experimento em vasos de polietileno com capacidade para 20 L, em Sobral, Ceará. O delineamento estatístico adotado foi em blocos ao acaso, disposto no esquema de parcelas subsubdivididas, com 5 repetições. As parcelas foram constituídas pelos ambientes de cultivo (céu aberto e telado, as subparcelas pelos níveis de salinidade da água de irrigação (CEa: 0,3;1,5; 3,0; 4,5 e 6,0 dS m-1 e as subsubparcelas foram representadas pela ausência e presença de matéria orgânica. Aos 110 dias após a aplicação dos tratamentos (DAT, avaliaram-se: altura, massa seca da parte aérea (MSPA, da raiz (MSR, total (MST e área foliar (AF, e aos 90 (DAT os teores foliares de solutos orgânicos. Todas as variáveis de crescimento estudadas foram afetadas negativamente pela salinidade, sendo que o efeito observado a céu aberto foi mais expressivo do que no ambiente telado. A matéria orgânica não teve efeito atenuante sobre os efeitos deletérios da salinidade em plantas de noni. O acúmulo de prolina mostrou-se um sinalizador de dano causado pelo estresse, visto que os maiores acúmulos ocorreram nas plantas que sofreram maiores reduções no crescimento.

  1. Estabilidade temporal da potenciometria e da salinidade em vale aluvial no semiárido de Pernambuco Temporal stability of piezometric levels and salinity in an alluvial valley in the semiarid Pernambuco - Brazil

    Directory of Open Access Journals (Sweden)

    Robertson V. de P. Fontes Júnior

    2012-11-01

    Full Text Available As restrições no uso e na disponibilidade das águas subterrâneas nos aluviões do semiárido nordestino estão diretamente ligadas à sazonalidade e à variabilidade espacial de seus níveis potenciométricos e salinidade. A estabilidade temporal é de grande interesse, por facilitar o monitoramento, possibilitando se obter locais representativos acerca da área em estudo, constituindo-se em uma importante ferramenta para a gestão dos recursos hídricos subterrâneos. Com isto, o objetivo deste trabalho foi identificar áreas com estabilidade temporal do nível potenciométrico e da salinidade, em aquífero aluvial do Agreste Pernambucano. Foram utilizados o método das diferenças relativas e a validação por correlação entre a média no tempo do piezômetro estável e a média dos demais piezômetros. Quanto ao nível potenciométrico identificaram-se áreas estáveis que representam o comportamento médio enquanto para a salinidade as áreas estáveis não representam adequadamente a média do vale aluvial devido, possivelmente, às restrições de circulação hídrica e ao uso agrícola do solo.The restrictions in the use and availability of groundwater in alluvial aquifers of the northeastern semiarid are directly related to seasonal and spatial variability of piezometric levels and salinity. Temporal stability is of high interest for monitoring, allowing representative locations about the studied area to be identified, being an important tool for groundwater resources management. Thus, the objective of this work was to identify areas with temporal stability for the water table level and salinity in an alluvial aquifer in the 'Agreste' region of Pernambuco State in Brazil. The relative difference method was used and also the validation by correlation between the mean response of one stable piezometer against the mean of all other piezometers, performed in time. For the water table level, stable areas representing the mean behavior

  2. Nitrato modula os teores de cloreto e compostos nitrogenados em plantas de milho submetidas à salinidade Nitrate modulates the contents of chloride and N-compounds in maize plants under salinity

    Directory of Open Access Journals (Sweden)

    Alexcyane Rodrigues Feijão

    2013-03-01

    Full Text Available O objetivo deste trabalho foi estudar o efeito do nitrato (NO3- no crescimento e no acúmulo de solutos inorgânicos e orgânicos em plantas de milho submetidas à salinidade. O delineamento experimental foi o inteiramente casualizado, com cinco repetições, sob esquema fatorial 2×4, constando de oito tratamentos: dois níveis de salinidade (NaCl a 0 e 75 mM e quatro concentrações de NO3- (0,5; 2,5; 5,0 e 7,5 mM em sistema hidropônico. A massa seca da parte aérea e das raízes foi reduzida pela salinidade, porém isso foi menos evidente quando as plantas foram submetidas a concentrações de NO3- abaixo de 2,5 mM. O melhor crescimento das plantas foi observado na concentração aproximada de NO3- a 5,0 mM. Os teores de Na+ e Cl- aumentaram com a salinidade em todos os órgãos estudados, havendo maior acúmulo desses íons nas raízes. De modo geral, os teores de K+ foram pouco afetados por esse estresse. Com o aumento da concentração de NO3- no meio, houve melhora na absorção desse íon, levando à redução da absorção de Cl- e ao acúmulo de prolina e N-aminossolúveis. O estresse nutricional é mais limitante ao crescimento das plantas de milho que o estresse salino, cujos efeitos prejudiciais são minimizados por uma nutrição de NO3- adequada.This work aimed to study the effect of nitrate (NO3- on growth and accumulation of inorganic and organic solutes in maize plants subjected to salinity. The experiment was carried out in a completely randomized design, with five replications, and a 2×4 factorial scheme, consisting of eight treatments: two salinity levels (NaCl at 0 or 75 mM and four different concentrations of NO3- (0.5, 2.5, 5.0 or 7.5 mM in nutrient solution. The dry mass of shoots and roots was reduced by salinity, however, this was less evident when plants were exposed to concentrations of NO3- below 2.5 mM. The best growth was observed in the approximate concentration of 5.0 mM NO3-. The Na+ and Cl- contents

  3. Estimation of leaf area for greenhouse cucumber by linear measurements under salinity and grafting Estimativa da área foliar do pepino em ambiente protegido por medidas lineares sob salinidade e enxertia

    Directory of Open Access Journals (Sweden)

    Flávio Favaro Blanco

    2005-08-01

    Full Text Available The measurement of leaf area by linear parameters is a useful tool when plants cannot be destroyed for direct measurement. The objectives of this study were to establish equations to estimate the leaf area of greenhouse-cucumber and to evaluate the effects of salinity and grafting on this estimative. Non-grafted cucumber seedlings, cv. 'Hokushin', were transplanted in a greenhouse and were irrigated with water of different salinities (1.0, 3.2 and 5.0 dS m-1. In the second growing period, the same cultivar was grafted on Cucurbita spp. and the plants were irrigated with water of 1.4, 3.0 and 5.3 dS m-1. Leaves of different sizes were collected from both experiments and leaf area was determined by an integrating area meter. Leaf length (L and width (W were also recorded. An equation for estimating the leaf area from L and W was developed for a given salinity level or grafting condition and estimated well the area of leaves collected in the other treatments. The leaf area (LA of cucumber 'Hokushin' could be estimated using the equation LA = 0.88LW - 4.27, for any grafting and salinity conditions.A determinação da área foliar por medidas lineares é uma ferramenta útil quando as plantas não podem ser destruídas para que a medição direta seja realizada. Os objetivos desse trabalho foram definir equações para a estimativa da área foliar do pepino em ambiente protegido e avaliar os efeitos da salinidade e da a enxertia nessa estimativa. Mudas de pepino, cv. 'Hokushin', não enxertadas, foram transplantadas em um ambiente protegido e irrigadas com água de diferentes salinidades (1,0, 3,2 e 5,0 dS m-1. No segundo período de cultivo, a mesma cultivar foi enxertada sobre Cucurbita spp., sendo as plantas irrigadas com água de 1,4, 3,0 e 5,3 dS m-1. Foram coletadas folhas de diferentes tamanhos dos dois cultivos e dos três tratamentos e a área foliar foi determinada por um medidor de área foliar. O comprimento (C e a largura (L da folha

  4. Interacção da salinidade e da fertilização azotada na produtividade do milho-grão Relationship between different levels of salinity and nitrogen and maize production

    OpenAIRE

    Gonçalves, M. C.; Martins, J.C.; N. Castanheira; Santos, F. L.; Neves, M. J.; Reis, J.; Prazeres, A.; Ramos, T.; Fonte, S.; F. Pires; M. Bica; J. Bica

    2007-01-01

    Instalaram-se, em 2004 e 2005, dois ensaios de campo (Évora e Alvalade), em solos diferentes, com mobilização convencional e a cultura de milho-grão regada com sistema gota-a-gota, em fonte tripla linear. Neste sistema existem 3 fontes: água salina, água de rega e solução fertilizante, de modo a obter dois gradientes, um de salinidade (adiç��o de NaCl), e outro de fertilizante (adição de solução azotada). Pretende-se avaliar o efeito da interacção da aplicação da água da rega salina e da fert...

  5. Produção do algodoeiro em função da salinidade e tratamento de sementes com regulador de crescimento Cotton yield as a function of salinity and seeds treatment with growth regulator

    Directory of Open Access Journals (Sweden)

    Francisco de Assis de Oliveira

    2012-06-01

    Full Text Available Este trabalho foi realizado com o objetivo de avaliar o efeito de diferentes níveis de salinidade da água de irrigação e sementes tratadas com regulador de crescimento na produção do algodoeiro. O delineamento experimental adotado foi inteiramente ao acaso, arranjados em esquema fatorial 5 x 2 com quatro repetições. Os tratamentos resultaram da combinação de cinco níveis de condutividade elétrica da água de irrigação (S1-0,5; S2-2,0; S3-3,5; S4-5,0 e S5-6,5 dS m-1 em sementes tratadas e não tratadas com regulador de crescimento. As variáveis avaliadas foram: produção de algodão em caroço, produção de sementes e de fibra, peso de 100 sementes e porcentagem de fibra. Não houve interação entre os níveis de salinidades e as sementes tratadas com regulador de crescimento. Os parâmetros produtivos do algodoeiro são reduzidos com uso de água de salinidade a partir de 3,5 dS m-1, independente das sementes serem tratadas com regulador de crescimento. As características agronômicas: peso de 100 sementes, porcentagem de fibra e produção de algodão em caroço não são influenciadas pelo cloreto de mepiquat. O tratamento das sementes com regulador de crescimento não afeta o efeito adverso da salinidade.This study was conducted to evaluate the effect of different salinity levels of irrigation water and seed treated with growth regulator on the yield of cotton. It was used an entirely statistical randomized design, in a factorial scheme 5 x 2, with four replications. The treatments resulted from the combination of four salinity levels of irrigation water (S1-0.5; S2-2.0; S3-3.5; S4-5.0 and S5-6.5 dS m-1 in treated and untreated seeds with growth regulator. The variables were: production of cotton, seed and fiber, 100 seed weight and percentage of fiber. There was not interaction between salinity levels and seed treated. The parameters of cotton production are reduced with the use of water salinity from 3.5 dS m-1

  6. Nitrato modula os teores de cloreto e compostos nitrogenados em plantas de milho submetidas à salinidade Nitrate modulates the contents of chloride and N-compounds in maize plants under salinity

    Directory of Open Access Journals (Sweden)

    Alexcyane Rodrigues Feijão

    2013-01-01

    Full Text Available O objetivo deste trabalho foi estudar o efeito do nitrato (NO3- no crescimento e no acúmulo de solutos inorgânicos e orgânicos em plantas de milho submetidas à salinidade. O delineamento experimental foi o inteiramente casualizado, com cinco repetições, sob esquema fatorial 2×4, constando de oito tratamentos: dois níveis de salinidade (NaCl a 0 e 75 mM e quatro concentrações de NO3- (0,5; 2,5; 5,0 e 7,5 mM em sistema hidropônico. A massa seca da parte aérea e das raízes foi reduzida pela salinidade, porém isso foi menos evidente quando as plantas foram submetidas a concentrações de NO3- abaixo de 2,5 mM. O melhor crescimento das plantas foi observado na concentração aproximada de NO3- a 5,0 mM. Os teores de Na+ e Cl- aumentaram com a salinidade em todos os órgãos estudados, havendo maior acúmulo desses íons nas raízes. De modo geral, os teores de K+ foram pouco afetados por esse estresse. Com o aumento da concentração de NO3- no meio, houve melhora na absorção desse íon, levando à redução da absorção de Cl- e ao acúmulo de prolina e N-aminossolúveis. O estresse nutricional é mais limitante ao crescimento das plantas de milho que o estresse salino, cujos efeitos prejudiciais são minimizados por uma nutrição de NO3- adequada.This work aimed to study the effect of nitrate (NO3- on growth and accumulation of inorganic and organic solutes in maize plants subjected to salinity. The experiment was carried out in a completely randomized design, with five replications, and a 2×4 factorial scheme, consisting of eight treatments: two salinity levels (NaCl at 0 or 75 mM and four different concentrations of NO3- (0.5, 2.5, 5.0 or 7.5 mM in nutrient solution. The dry mass of shoots and roots was reduced by salinity, however, this was less evident when plants were exposed to concentrations of NO3- below 2.5 mM. The best growth was observed in the approximate concentration of 5.0 mM NO3-. The Na+ and Cl- contents

  7. Efecto de la salinidad sobre la fisiología energética del camarón blanco Litopenaeus vannamei (Boone) Effect of salinity on physiological energetics of white shrimp Litopenaeus vannamei (Boone)

    OpenAIRE

    Gustavo Valdez; Fernando Díaz; Ana Denisse Re; Elizabeth Sierra

    2008-01-01

    Se determinó el balance energético en juveniles de Litopenaeus vannamei, aclimatados a la salinidad como hiperosmóticos (20 ups), isosmóticos (26 ups), o hiposmóticos (32 ups). Además, se calculó la razón atómica O:N. La tasa de ingestión, el consumo de oxígeno, la excreción de amonio y el campo de crecimiento fueron afectados significativamente (p < 0.05) cuando los organismos fueron aclimatados a 20, 26 y 32 ups. La mayor cantidad de energía ingerida contenida en el alimento se determinó en...

  8. Effects of salinity on the development of rocket grown on different substrates hydroponic. = Efeitos da salinidade sobre o desenvolvimento de rúcula cultivada em diferentes substratos hidropônicos.

    Directory of Open Access Journals (Sweden)

    Maria Lilia de Souza Neta

    2013-08-01

    Full Text Available This study evaluated the effects of salinity on the nutrient solution on the production of rocket, grown on different substrates. The test was developed in an environment protected by the Department of Environmental Sciences and Technology, Federal Rural University of the Semi-Arid in Mossoró-RN, housed in a completely randomized design in a factorial 3 x 5 with three replications. Five salinity levels of nutrient solution were used, obtained with or without the fish farming wastewater (S1-0.5, S2-2.0, S3-3.5, S4-5.0 and S5-6.5 dS m-1 and three substrates (SUB1-Mix coconut fibre + sand + rice husk (1:1:1, SUB2-Cambisol and SUB3-SUB1 reused in the previous experiment. Harvesting of rocket was performed at 35 days aftersowing and evaluated the following variables: plant height, leaf number, leaf area, fresh weight, and dry weight. The salinityof the nutrient solution negatively affected the development of the rocket grown, having effect varying according to the type of substrate used. The plants grown on the substrate formed by the mixture of coconut fibre + sand + rice hulls (1:1:1 showed higher tolerance to salinity. The substrate formed by mixing coir + sand + rice husk can be recommended for growing rocket containers, but cannot be reused without treatment. = Objetivou-se com este trabalho avaliar o efeito da salinidade na solução nutritiva sobre a produção de rúcula, cultivada em diferentes substratos. O ensaio foi desenvolvido em ambiente protegido do Departamento de Ciências Ambientais e Tecnológicas da Universidade Federal Rural do Semi-Árido em Mossoró-RN, e instalado em delineamento experimental inteiramente casualizado, em esquema fatorial 5 x 3, com três repetições. Foram utilizados cinco níveis de salinidade na solução nutritiva, obtidos com ou sem uso de água residuária da piscicultura (S1-0,5; S2-2,0; S3-3,5; S4-5,0 e S5-6,5 dS m-1 e três substratos (SUB1-Mistura de fibra de coco + areia + casca de arroz (1

  9. Comportamento de mudas de nim à salinidade da água em solo não salino com biofertilizante Behavior of neem seedlings under water salinity in a non-saline soil with biofertilizer application

    OpenAIRE

    Járisson C. Nunes; Lourival F. Cavalcante; Antonio J. de Lima Neto; Alex M. Rebequi; Belísia L. M. T. Diniz; Hans R. Gheyi

    2012-01-01

    Um experimento foi desenvolvido em ambiente telado do Departamento de Solos e Engenharia Rural da Universidade Federal da Paraíba, Areia, PB, no período de janeiro a abril de 2010. O substrato constou de material de um Neossolo Quartzarênico não salino, coletado na camada de 0-20 cm. Os tratamentos foram dispostos em delineamento inteiramente casualizado em esquema fatorial 5 x 2, referente aos níveis de salinidade da água de irrigação de 0,5; 1,0; 2,0; 3,0 e 4,0 dS m-1, no solo sem e com bio...

  10. Alternativa de Convivencia con el Problema de la Salinidad del Agua de Irrigación causada por Presas Subterráneas Alternative of Coexistence with the Salinity Probiem of Irrigation Water caused by Underground Dams

    Directory of Open Access Journals (Sweden)

    José Wilmar  da S Neto

    2011-01-01

    Full Text Available Se presenta una alternativa de convivencia con el problema de salinidad del agua de irrigación causado por presas subterráneas. Se analiza la calidad del agua de irrigación comparando el crecimiento vegetativo de las gramíneas Capim Vetiver, Sempre Verde; Cana-de-agúcar, Capim Elefante cv. Napier y Capim Elefante cv. Mercker, aguas arriba y abajo de la presa subterránea localizada en el municipio de Ibicuitinga, estado de Ceará en Brasil. El análisis de muestras de aguas subterráneas aguas arriba y abajo de la presa han mostrado que ambas poseen un grado de salinidad elevado para fines de irrigación, recomendándose el uso de cultivos halófitos. Se ha realizado el análisis de varianza para variable crecimiento en altura y se ha aplicado la prueba de Tukey. A partir de esta prueba se ha verificado que, de entre las gramíneas probadas, tan sólo la Capim Elefante cv. Mercker ha diferido estadísticamente.The objective of this paper is to show an alternative for the coexistence with the salinity probiem of irrigation water caused by underground dams. The quality of irrigation water is analyzed by comparing the vegetative growth of Capim Vetiver, Sempre Verde, Cana-de-Acucar, Capim Elefante cv. Napier and Capim Elefante cv. Mercker, upstream and downstream of the underground dam located in Ibicuitinga, Ceará state in Brazil. The analysis of groundwater samples upstream and downstream of the dam have shown that both have high salinity for irrigation, recommending the use of halophytes crops. The study includes an analysis of variance for height growth variable and the Tukey test was applied. From this test it was verified that among the gramineous plants tested, only the Capim Elefante cv. Mercker was found statistically different.

  11. Compostos nitrogenados e carboidratos em sorgo submetido à salinidade e combinações de nitrato e amônio Nitrogenous compounds and carbohydrates in sorghum subjected to salinity and combinations of nitrate and ammonium

    Directory of Open Access Journals (Sweden)

    Ana Karla Moreira Lobo

    2011-06-01

    Full Text Available O objetivo do trabalho foi avaliar os efeitos de combinações de nitrato e amônio no meio, na acumulação de compostos nitrogenados e carboidratos, na presença e ausência de salinidade em plantas de sorgo. Sementes do genótipo CSF 20 foram cultivadas em casa de vegetação, em solução nutritiva com três concentrações de nitrato e amônio (100% NO3-: 0% NH4+, 75% NO3-: 25% NH4+ e 0% NO3-: 100% NH4+, na presença e ausência de salinidade. A salinidade reduziu a concentração de nitrato nas folhas e colmo, nos tratamentos 100:0 e 75:25. O amônio acumulou-se mais nas plantas com NaCl, nas folhas e colmo. Os teores de aminoácidos livres totais nas folhas não se alteraram, mas, no colmo, aumentaram na presença de sal e aumento do amônio. A concentração de prolina livre nas folhas e colmo elevou-se nas plantas sob salinidade. O conteúdo de nitrogênio total foi maior nas folhas, entretanto não houve grandes alterações com a presença do sal. A concentração de carboidratos solúveis totais foi maior nas plantas tratadas com sal, exceto no colmo 0:100. Nas folhas, o teor de sacarose foi reduzido na presença do NaCl e aumento de amônio, enquanto, no colmo, foi maior no tratamento 75:25 com NaCl. O teor de amido não sofreu alterações com as diferentes combinações nas formas de N e salinidade. Conclui-se que combinações de NO-3 e NH4+ no meio afetam a acumulação de compostos nitrogenados e carboidratos em folhas e colmo, com presença ou ausência de salinidade, em plantas de sorgo forrageiro.The objective of this study was to evaluate the effects of combinations of nitrate and ammonium in the medium, on the accumulation of nitrogen compounds and carbohydrates, in the presence and absence of salinity in sorghum plants. CSF 20 genotype sorghum seeds, were grown in the greenhouse and supplied with a nutritive solution at three different concentrations of nitrate and ammonium (100% NO3-: 0% NH4+, 75% NO3-: 25% NH4+ e 0% NO3

  12. Exercise and Pulmonary Hypertension (PH)

    Science.gov (United States)

    ... Siblings Cope Parents Weigh in on Sibling Issues Co-Parenting a Child with PH You and Your Partner: ... Siblings Cope Parents Weigh in on Sibling Issues Co-Parenting a Child with PH You and Your Partner: ...

  13. Laryngopharyngeal pH measurement

    OpenAIRE

    Spurrier, E; Clancy, M; Deakin, C

    2004-01-01

    Methods: Cohorts of unconscious adult ED and elective surgical patients were recruited. The posterior pharyngeal wall pH was measured immediately before and after intubation. Pharyngeal pH was used to indicate risk of aspiration, and pH change to assess the efficacy of cricoid pressure.

  14. Requerimientos de proteína y energía bruta en juveniles de camarón rosado Farfantepenaeus paulensis (Pérez-Farfante, 1967 sometidos a diferentes salinidades Gross protein and energy requirements for pink shrimp Farfantepenaeus paulensis (Pérez-Farfante, 1967 juvenile under different salinities

    Directory of Open Access Journals (Sweden)

    Roberto Ramos

    2011-11-01

    Full Text Available Se determinó el requerimiento de proteína (PB y energía bruta (EB y su relación óptima en dietas prácticas para juveniles de camarón rosado Farfantepenaeus paulensis en diferentes salinidades. Se sembraron camarones con peso promedio de 0,353 g en 54 estanques de PVC con densidad inicial de 40 ind m-2. El experimento fue factorial, con tres niveles de proteína bruta 24, 35 y 48%, tres salinidades 10, 20 y 30 psu y dos niveles de energía bruta 3200 y 4200 kcal kg-1 de dieta, con tres réplicas, en un período experimental de 25 días. Los resultados indicaron que la salinidad y la proteína tuvieron un efecto significativo (P 0,05 sobre la sobrevivencia, tasa de crecimiento específica y ganancia en peso. La respuesta de los camarones a las necesidades de proteína y energía bruta en las salinidades probadas fue diferente. En la salinidad de 10 psu los requerimientos fueron 35% PB y 4200 kcal kg-1 (83,3 mg PB kcal-1, mientras que en salinidades de 20 y 30 psu fueron 25% de PB y 3200 kcal kg-1 (75,0 mg PB kcal-1.The requirement of gross protein and energy and the optimal ratio of these in practical diets for pink shrimp (Farfantepenaeus paulensis juveniles in different salinities were determined. Shrimp with a mean initial weight of 0.353 g were stocked in 54 plastic tanks at initial densities of 40 ind m-2. The experiment was factorial, with three levels of gross protein (24, 35, 48%, three levels of salinities (10, 20, 30 psu, and two levels of gross energy (3200, 4200 kcal kg-1; the experiment lasted 25 days and considered three replicates. The results showed that salinity and protein had a significant effect (P < 0.05 on weight gain and the specific growth rate, but did not influence on survival. The energy had no significant effect on survival, growth rate, or weight gain. The response of the shrimp to the gross energy and protein level showed different requirements according to the different salinities tested. At salinity of 10 psu

  15. ALS - resources

    Science.gov (United States)

    Resources - ALS ... The following organizations are good resources for information on amyotrophic lateral sclerosis : Muscular Dystrophy Association -- mda.org/disease/amyotrophic-lateral-sclerosis National Amyotrophic Lateral Sclerosis (ALS) Registry -- ...

  16. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2000-06-01

    Full Text Available Report of PhD Dissertations.   Miguel Calleja Puerta El conde Suero Vermúdez, su parentela y su entorno social. La aristocracia leonesa en los siglos XI y XII, Tesis de doctorado en Historia, Universidad de Oviedo (España, 2000   Adele Cilento Potere e monachesimo nella Calabria bizantina: relazioni e interferenze (secc. IX-XI, Tesi di dottorato di ricerca in Storia medievale (X ciclo, Università degli Studi di Torino, 2000   Amedeo De Vincentiis Firenze e i signori. Sperimentazioni istituzionali e modelli di regime nelle signorie fiorentine degli Angioini (fine XIII - metà XIV secolo, Tesi di dottorato di ricerca in Storia medioevale (XI ciclo, Università degli Studi di Milano, 1999   Marco Folin Il sistema politico di un antico Stato italiano: i ducati estensi nella prima Età moderna (1452-1598, Tesi di dottorato di ricerca in Storia, Scuola Normale superiore di Pisa, 2000   Barbara Frale Guardiani del Santuario. Le radici orientali del processo contro l’ordine del Tempio (1128 - 1314, Tesi di dottorato di ricerca in Storia sociale d’Europa (XI ciclo, Università "Ca’ Foscari" di Venezia, 2000

  17. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2003-12-01

    Full Text Available Report of PhD Dissertations. Guido Antonioli Conservator pacis et iustitie. La signoria di Taddeo Pepoli a Bologna (1337-1347, Tesi di dottorato di ricerca in Filologia romanza e cultura medievale (XIII ciclo, Università degli Studi di Bologna, 2001   Elisabetta Filippini «In vassallatico episcopi permanere debent». Rapporti vassallatici e concessioni beneficiali dei vescovi di Cremona fra X e XIII secolo, Tesi di dottorato di Ricerca in Storia Medievale (XV ciclo, Università Cattolica del Sacro Cuore di Milano, 2003   Marco Meschini, Innocenzo III e il "negotium pacis et fidei" in Linguadoca tra il 1198 e il 1215, Tesi di dottorato di ricerca in Storia medievale, Università Cattolica del Sacro Cuore, 2003   Fabrizio Ricciardelli The Politics of Exclusion in Florence (1215-1434, thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in History, University of Warwick, Department of History, April 2003 Renata Salvarani Baptizare pueros et decimas dare. Cura delle anime, strutturazione ecclesiastica e organizzazione delle campagne in area gardesana fra VIII e XIII secolo (diocesi di Brescia, Verona, Mantova e Trento, Tesi di dottorato in Storia medievale (XV ciclo, Università Cattolica del Sacro Cuore di Milano, 2002-2003   Vito Sibilio Le parole della prima crociata, Tesi di dottorato di ricerca in Storia dei centri delle vie e della cultura dei pellegrinaggi nel medioevo euromediterraneo, Università degli studi di Lecce, 2003

  18. Interacção da salinidade e da fertilização azotada na produtividade do milho-grão Relationship between different levels of salinity and nitrogen and maize production

    Directory of Open Access Journals (Sweden)

    M.C. Gonçalves

    2007-01-01

    Full Text Available Instalaram-se, em 2004 e 2005, dois ensaios de campo (Évora e Alvalade, em solos diferentes, com mobilização convencional e a cultura de milho-grão regada com sistema gota-a-gota, em fonte tripla linear. Neste sistema existem 3 fontes: água salina, água de rega e solução fertilizante, de modo a obter dois gradientes, um de salinidade (adiç��o de NaCl, e outro de fertilizante (adição de solução azotada. Pretende-se avaliar o efeito da interacção da aplicação da água da rega salina e da fertilização azotada, sem deixar de se conseguir níveis de produção aceitáveis. Cada área experimental integrava 4 grupos (I a IV, com três repetições, tendo-se utilizado um gradiente decrescente de fertilizante do Grupo I para o IV, sem solução azotada neste último grupo. Dentro de cada grupo estabeleceram-se 4 modalidades de salinidade em 2004 e apenas 3 em 2005, através da distribuição de diferentes quantidades de água salina ao longo das linhas da cultura. O conjunto de gotejadores debitava 18 L/h em cada ponto de rega e cada metro linear de cultura de milho. Nos dois anos em estudo, as regas com as soluções salina e azotada decorreram de Junho a Setembro, com frequência trissemanal no início, passando a diária. Nos dois anos monitorizou-se a solução do solo (condutividade eléctrica, teores em catiões solúveis e nitratos às profundidades de 20, 40 e 60 cm. Recolheram-se amostras de solo antes, durante e no fim dos ciclos de rega, nos 4 Grupos a 3 profundidades (0-20 cm; 20-40 cm; 40-60 cm, para determinação de vários parâmetros do solo, entre os quais a condutividade eléctrica do extracto de saturação do solo. Avaliou-se a produtividade do milho-grão nas diferentes modalidades e determinaram-se funções de produção e as curvas de resposta em função das quantidades totais de sais e de fertilizante azotado aplicados nos dois anos do ensaio (R²=0.62 n=55. Os resultados apontam para um efeito positivo

  19. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2002-06-01

    Full Text Available Report of PhD dissertation. Laura Baietto Una politica per le città. Rapporti fra papato, vescovi e comuni nell'Italia centro-settentrionale da Innocenzo III a Gregorio IX, Tesi di dottorato di ricerca in Storia Medievale, Università degli Studi di Torino, 2002   Giuseppe Banfo Compresenze e sovrapposizioni di poteri territoriali di qualità diversa tra X e XIII: il caso del basso Monferrato, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Torino, 2002   Francesca Dell'Acqua La vetrata tra l'età tardo imperiale e l'altomedioevo: le fonti, l'archeologia, Tesi di Perfezionamento in Storia dell'Arte Medievale, Scuola Normale Superiore di Pisa, 2001   Primo Giovanni Embriaco I vescovi di Albenga e gli sviluppi signorili nella Liguria occidentale (secoli XI-XIII, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Torino, 2001   Antonella Ghignoli Documenti e proprietà altomedievali. Fondamenti e problemi dell'esegesi storica delle fonti documentarie nello specchio della tradizione delle carte pisane dei secoli VIII-XI, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Firenze, 2002   Vito Loré Espansione monastica e mutamenti politici. La Trinità di Cava nei suoi rapporti con i sovrani longobardi e normanni e con l'aristocrazia territoriale. Secoli XI-XII, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Firenze, 2002   Rosaria Stracuzzi Messina nel '400, Tesi di dottorato di ricerca in Storia medievale, Università degli Studi di Palermo, 2001   Stefania Tamburini Le "portate" ecclesiastiche nel piviere di San Giovanni in Firenze nel 1427. Spunti per una riflessione sul patrimonio ecclesiastico della diocesi fiorentina,Tesi di dottorato di ricerca in Storia e informatica, Università degli Studi di Bologna, 2001

  20. PhD Dissertations

    Directory of Open Access Journals (Sweden)

    Redazione Reti Medievali (a cura di

    2004-12-01

    Full Text Available Report of PhD Dissertations. Massimo Della Misericordia Divenire comunità. Comuni rurali, poteri signorili, identità sociali in Valtellina e nella montagna lombarda nel tardo medioevo, Tesi di dottorato in Storia medievale (XIV ciclo, Università degli Studi di Torino, 2003   Mariano Dell’Omo Il monastero di S. Liberatore alla Maiella centro dell’irradiazione di Montecassino nell’Abruzzo medievale e moderno. Contributo alla storia dell’organizzazione patrimoniale e della civiltà monastica cassinese nell’Italia centrale attraverso i documenti di S. Liberatore conservati nell’Archivio di Montecassino. Introduzione storica, paleografica e archivistica. Edizione dei documenti più antichi (†798-1000 e regesti di quelli posteriori (1005-1735, Tesi di dottorato in Storia Ecclesiastica, Facoltà di Storia Ecclesiastica, Pontificia Università Gregoriana di Roma,  2004   Giulia Lorenzoni Conquistare e governare la città. Forme di potere e istituzioni nel primo anno della signoria viscontea a Bologna (ottobre 1350-novembre 1351, Tesi di dottorato in Storia medievale (XVI ciclo, Università degli Studi di Bologna, 2004   Federica Monteleone Il viaggio di Carlo Magno in Terra Santa. Un’esperienza di pellegrinaggio nella tradizione europea occidentale, Tesi di dottorato di ricerca in Storia dei centri, delle vie e della cultura dei pellegrinaggi nel Medioevo euro mediterraneo (XV ciclo   Francesca Pucci Donati Fra teorie mediche e pratica quotidiana: i calendari dietetici dell’Occidente latino altomedievale (secoli IX-XI, Tesi di dottorato di ricerca in Storia medievale (XV ciclo, Università degli studi di Bologna, 2004 Alberto Ricciardi L’Epistolario di Lupo di Ferrières come fonte per la storia degli intellettuali nell’età di Carlo il Calvo, Tesi di dottorato in Storia medievale (XV ciclo, Università degli Studi di Bologna, 2004   Francesco Paolo Terlizzi I trattati dell'Anonimo Normanno: ricerche di ecclesiologia, Tesi

  1. Crescimento de bananeiras sob diferentes níveis de salinidade da água de irrigação Growth in banana cultivars under different salinity levels of irrigation water

    Directory of Open Access Journals (Sweden)

    Gilcimar Alves do Carmo

    2003-12-01

    Full Text Available Avaliaram-se os efeitos do uso de diferentes níveis de salinidade da água de irrigação (S1 = 0,55 dS/m, S2 = 1,70 dS/m, S3 = 2,85 dS/m e S1 = 4,00 dS/m no crescimento vegetativo de bananeiras Pacovan (AAB e Marmelo (ABB, utilizando-se um solo Argissolo Crômico, textura franco-argilo-arenosa e adotando-se um delineamento experimental em blocos completos casualizados, com parcelas subdivididas e quatro repetições. As parcelas experimentais foram compostas de uma fileira com 10 plantas, sendo cinco de cada cultivar, com as três plantas centrais de cada sub-parcela consideradas úteis. As irrigações foram feitas diariamente ou a cada dois dias de modo a proporcionar uma fração de lixiviação ao redor de 0,15%, colocando-se volumes aproximados de água para manter o solo próximo à capacidade de campo. Os resultados obtidos aos 110, 160, 220, 300 e 360 dias após o plantio mostraram que o incremento nos níveis de salinidade diminuiu significativamente a altura da planta, o número de folhas e a área foliar com o aumento do nível de salinidade da água até no máximo 240 dias do desenvolvimento, havendo uma equiparação depois do período chuvoso.The effects of different salinity levels of irrigation water (S1 = 0.55 dS/m, S2 = 1.70 dS/m, S3 = 2.85 dS/m e S4 = 4.00 dS/m on vegetative growth in bananas Pacovan (AAB and Marmelo (ABB were evaluated. The experiment was carried out on a sandy clay loam Chromic Argisol in a split-plot scheme arranged in a randomized block design with four replications. The whole plots were composed of a row with 10-plants, five plants of each cultivar (subplot, and the data were collected from the three central ones. The irrigations were applied either dayly or every each two-days period in order to maintain a lixiviation fraction of 0.15, using approximate water sheets to keep the soil at field capacity. The data obtained at 110, 160, 220, 300, and 360 days after planting indicated that the water

  2. CRESCIMENTO E SOBREVIVÊNCIA DO CAMARÃO BRANCO DO PACIFÍCO Litopenaeus vannamei (BOONE, 1931 EM DIFERENTES SALINIDADES GROWTH AND SURVIVAL OF PACIFIC WHITE SHRIMP Litopenaeus vannamei (BOONE, 1931 IN DIFFERENT SALINITIES

    Directory of Open Access Journals (Sweden)

    Carlos Henrique dos Anjos dos Santos

    2009-09-01

    Full Text Available O presente estudo teve como objetivo avaliar o desenvolvimento de pós-larvas de Litopenaeus vannamei cultivadas em diferentes salinidades. Realizou-se o experimento no Centro de Tecnologia em Aquicultura da Universidade Federal do Ceará, durante o período de 1.o de setembro de 2006 a 31 de outubro de 2006. Em vinte aquários com volume útil de 30L foram distribuídos, em um delineamento inteiramente casualizado, cinco tratamentos (controle – 35%, 30‰, 20‰, 10‰ e 0‰ com quatro repetições cada. Foi utilizada a densidade de trinta indivíduos/aquário. As pós-larvas, em fase de PL 10, apresentavam peso e comprimento médio total inicial de 0,008 ± 0,001g e 11,00 ± 0,05mm, respectivamente. Os animais foram, gradativamente, aclimatados nas salinidades experimentais. Para as análises estatísticas, aplicou-se a análise de variância (ANOVA e, posteriormente, caso se verificassem diferenças significativas entre os tratamentos, o teste Tukey de separação de médias (? = 0,001. Os parâmetros de qualidade de água analisados mantiveram-se dentro dos padrões aceitáveis para o cultivo da espécie. As pós-larvas cultivadas em 0‰ apresentaram os melhores valores de peso final, incremento em peso, incremento relativo diário de biomassa e taxa de sobrevivência (P<0,001. Todavia, os animais cultivados em 10% mostraram os melhores valores de comprimento total e incremento em comprimento (P<0,001. Os resultados do presente estudo sugerem que pós-larvas de L. vannamei apresentam taxas similares de crescimento e sobrevivência quando cultivadas em diferentes salinidades.

    PALAVRAS-CHAVES: Gradiente salino, laboratório Litopenaeus vannamei, osmorregulação.
    The aim of this work was to evaluate the development of Litopenaeus vannameiat post-larvae (PL at different salinities. This experiment was carried out at the “Centro de Tecnologia em Aqüicultura/UFC” at the period from 01/09/2006 to 31/10/2006. Twenty

  3. Efecto de la temperatura y salinidad sobre la germinación y crecimiento de plántulas de dos variedades de Chenopodium quinoa Temperature and salinity effects on germination and seedling growth on two varieties of Chenopodium quinoa

    Directory of Open Access Journals (Sweden)

    G. Chilo

    2009-06-01

    Full Text Available Se estudió el efecto de la temperatura y salinidad sobre la germinación y crecimiento de plántulas de dos variedades de Chenopodium quinoa. Se diseñó un experimento factorial con tres factores: 1 variedad, con dos niveles (Cica y Real; 2 temperatura, con tres niveles (5 ºC, 10 ºC y 20 ºC; y 3 salinidad, con cinco niveles (0,0; 0,1; 0,2; 0,3 y 0,4M de cloruro de sodio. Los ensayos se realizaron según normas ISTA, las variables de respuesta fueron: poder germinativo como porcentaje de plántulas normales, velocidad de germinación y crecimiento de plántulas. Se determinaron porcentajes de plántulas normales, anormales y semillas muertas; además, peso seco y contenido de sodio y potasio. En las variedades Cica y Real el descenso de temperatura y aumento de salinidad produjeron una disminución del poder germinativo, de la velocidad de germinación y del crecimiento de las plántulas; además, afectaron el peso seco y los porcentajes de plántulas normales, anormales y semillas muertas. Las variedades acumularon solutos en las vacuolas de las células epidérmicas del tallo y hojas. La variedad Cica presentó mejor respuesta a la germinación y crecimiento de plántulas en comparación con la variedad Real.The effect of temperature and salinity on germination and seedling growth was studied in two varieties of Chenopodium quinoa. A factorial experiment with three factors was designed: 1 variety (two levels: Cica and Real; 2 temperature, (three levels: 5 ºC, 10 ºC and 20 ºC and 3 salinity (five levels: 0.0, 0.1, 0.2, 0.3 and 0.4M of sodium chloride. The tests were carried out according to ISTA rules. The response variables were: germination rate as a percentage of normal seedlings; germination speed and seedling growth. Percentage of normal seedlings, abnormal and dead seeds, together with dry weight and sodium and potassium content were determined. In Cica and Real varieties, decreasing temperature and increasing salinity caused a

  4. Rotação cultural feijão caupi/milho utilizando-se águas de salinidades diferentes Cowpea/corn crop rotation utilizing waters of different salinities

    Directory of Open Access Journals (Sweden)

    Anna Karine Paiva Bezerra

    2010-05-01

    Full Text Available O objetivo do presente trabalho foi avaliar as alterações nas propriedades químicas do solo, no crescimento e na produtividade, em um ciclo de rotação cultural feijão caupi/milho irrigado, com águas de diferentes salinidades. O experimento foi conduzido em Fortaleza, Ceará (CE, seguindo-se o delineamento em blocos ao acaso, com quatro tratamentos e cinco repetições, totalizando 20 parcelas. Os tratamentos estudados foram: plantas irrigadas por sulcos com água do poço com CEa de 0,8 (T1; 2,2 (T2; 3,6 (T3; e 5,0dS m-1(T4. Utilizou-se, primeiramente, o cultivo do feijão caupi (estação seca, com espaçamento de 0,8m entre linhas e 0,3m entre plantas, com duas plantas por cova. As parcelas permaneceram demarcadas para o cultivo do milho (estação chuvosa, com espaçamento de 0,8m entre linhas e 0,2m entre plantas e uma planta por cova. Foram avaliadas as propriedades químicas do solo, o crescimento vegetativo, a produtividade e a partição da matéria seca. A aplicação de água salina durante o cultivo do feijão caupi na estação seca aumentou a salinidade e a sodicidade do solo, reduzindo o crescimento e a produtividade do feijão caupi. As elevadas precipitações pluviométricas antes e durante o cultivo do milho reduziram os prováveis efeitos negativos da salinidade nessa cultura. As elevadas produtividades das culturas e as pequenas alterações nos teores de sais no solo sugerem a viabilidade de utilização da rotação cultural feijão caupi/milho nas condições semelhantes às do presente estudo.The objective of this study was to evaluate the changes in chemical properties of soil, growth and productivity of crops in a cowpea/corn rotation irrigated with water of different salinities. The experiment was conducted under field conditions in randomized block design in a factorial scheme with four treatments and five replications totaling twenty plots. The treatments consisted of plants irrigated with well water of ECw of

  5. Aluminum tolerance of two wheat cultivars (Brevor and Atlas66) in relation to their rhizosphere pH and organic acids exuded from roots.

    Science.gov (United States)

    Wang, Ping; Bi, Shuping; Ma, Liping; Han, Weiying

    2006-12-27

    Phytotoxicity of aluminum (Al) has become a serious problem in inhibiting plant growth on acid soils. Under Al stress, the changes of rhizosphere pH, root elongation, absorption of Al by wheat roots, organic acids exuded from roots, and some main factors related to Al-tolerant mechanisms have been studied using hydroponics, fluorescence spectrophotometry, and high performance liquid chromatography (HPLC). Two wheat cultivars, Brevor and Atlas66, differing in Al tolerance are chosen in the study. Accordingly, the rhizosphere pH has a positive effect on Al tolerance. Atlas66 (Al-tolerant) has higher capability to maintain high rhizosphere pH than Brevor (Al-sensitive) does. High pH can reduce Al3+ activity and toxicity, and increase the efficiency of exuding organic acids from the roots. More inhibition of root elongation has been found in Brevor because of the exposure of roots to Al3+ solution at low pH. Brevor accumulate more Al in roots than Atlas66 even at higher pH. Al-induced exudation of malic and citric acids has been found in Atlas66 roots, while no Al-induced organic acids have been found in Brevor. These results indicate that the Al-induced secretion of organic acids from Atlas66 roots has a positive correlation with Al tolerance. Comprehensive treatment of Al3+ and H+ indicates that wheat is adversely influenced by excess Al3+, rather than low pH. PMID:17177538

  6. Determining Critical Soil pH for Sunflower Production

    Directory of Open Access Journals (Sweden)

    Apurba Sutradhar

    2014-01-01

    Full Text Available Soil acidity has become a major yield-limiting factor in cropping systems of the Southern Great Plains, in which winter wheat (Triticum aestivum L. is the predominant crop. Sunflower (Helianthus annuus L. is a strong rotational crop with winter wheat due to its draught and heat tolerance. However, the effects of low soil pH on sunflower productivity have not been explored. The objective of this study was to determine the critical soil pH and aluminum concentration (AlKCl for sunflower. Sunflower was grown in a randomized complete block design with three replications of a pH gradient ranging from 4.0 to 7.0 at three locations with varying soil types. Soil pH was altered using aluminum sulfate (Al2(SO43 and hydrated lime (Ca(OH2. Plant height, vigor, and survivability were all negatively affected by soil acidity. Sunflower yield was reduced by 10% at or below soil pH 4.7 to 5.3 dependent upon location and soil type. Levels of AlKCl above 6.35 mg kg−1 reduced seed yield by 10% or greater. We concluded that sunflower may serve as a better rotational crop with winter wheat under acidic conditions when compared to other adaptable crops.

  7. Effect of salinity on growth and chemical composition of the diatom Thalassiosira weissflogii at three culture phases Efecto de la salinidad en el crecimiento y composición química de la diatomea Thalassiosira weissflogii en tres fases de cultivo

    Directory of Open Access Journals (Sweden)

    Norma García

    2012-07-01

    Full Text Available The estuarine diatom Thalassiosira weissflogii (Fryxell & Hasle, 1977 has been widely used as live feed in aquaculture. The growth rate and biochemical composition of microalgae are highly influenced by environmental factors such as, light, salinity and nutrient availability. Salinity is difficult to control in some shrimp laboratories specialized in larvae production, because these laboratories depend upon the levels measured in estuaries or coastal lagoons, which are the water sources for larvae culture. The present study evaluated the effect of different salinities (25, 30, 35, 40, 45 and 50 psu, on the growth and chemical composition of T. weisflogii at three culture phases, under laboratory conditions. The highest growth rate and maximum cell density were found at 25 psu. Decrease in size and striking changes in morphology of the cells were observed at the higher salinities and drastic changes occurred at 50 psu. Protein and carbohydrate content were higher at low salinities (25 and 30 psu during the stationary phase. The lipid production was higher at low salinities, but diminished as the phase changes occurred; in contrast, the lipid content was unaffected by the growth phase at higher salinities (≥ 35 psu. The higher growth rate and better biochemical composition were obtained at 25 and 30 psu.La diatomea estuarina Thalassiosira weissflogii (Fryxell & Hasle, 1977 ha sido utilizada como alimento vivo en acuacultura. La composición bioquímica del alimento vivo afecta la nutrición de los organismos durante su cultivo. La tasa de crecimiento y composición bioquímica de las microalgas están altamente influenciadas por factores ambientales como luz, salinidad y disponibilidad de nutrientes. En algunos laboratorios productores de larvas de camarón, es difícil controlar la salinidad, debido a que éstos dependen de los niveles presentes en estuarios o lagunas costeras, los cuales son la fuente de agua para el cultivo larvario. El

  8. Phaeacians at the birthday party: A.P. 11.44 (Philodemus and its epic background Les Phéaciens à la fête : A.P. 11,44 (Philodème et son arrière-plan épique Feaci al banchetto: A.P. 11.44 (Filodemo e il suo background epico

    Directory of Open Access Journals (Sweden)

    Anja Bettenworth

    2012-07-01

    Full Text Available Dans son célèbre poème d’invitation adressé à Pison, Philodème se réfère explicitement à l’épisode phéacien d’Homère, quand il décrit les plaisirs qui attendent son hôte. Par voie de conséquence, la discussion portant sur les allusions épiques du poème de Philodème se sont principalement concentrées sur le copieux banquet à Schérie. Cet article montre que, à côté du modèle phéacien, Philodème évoque aussi le séjour d’Ulysse dans l’humble cabane d’Eumée. L’allusion à ces deux scènes homériques d’hospitalité permet de souligner la combinaison de biens matériels et immatériels qui caractérise le festin à venir de Philodème. L’allusion à Homère souligne également le sous-entendu poétique de l’épigramme en général et, de manière plus spécifique, permet de clarifier la signification très controversée du vers 7.Nel suo celebre carme di invito a Pisone, Filodemo fa esplicito riferimento all’episodio omerico dei Feaci quando descrive i piaceri che attendono i suoi ospiti. La discussione delle allusioni epiche nel carme di Filodemo si è di conseguenza concentrata soprattutto sull’abbondante banchetto a Scheria. Questo articolo intende mostrare che, insieme al modello feace, Filodemo evoca anche il soggiorno di Odisseo nell’umile capanna di Eumeo. L’allusione a due scene omeriche di accoglienza aiuta a mettere in evidenza la combinazione di beni materiali e immateriali che contraddistingue l’imminente festa di Filodemo. L’allusione ad Omero, inoltre, sottolinea le implicazioni poetiche dell’epigramma in generale e, più specificamente, aiuta a chiarificare il dibattuto significato del verso 7.In his famous invitation poem to Piso, Philodemus explicitly refers to the Homeric Phaeacian episode when he describes the pleasures awaiting his guest. As a consequence, the discussion of epic allusions in Philodemus’ poem has mostly focused on the lavish banquet on Scheria. This

  9. PhEDEx Data Service

    Energy Technology Data Exchange (ETDEWEB)

    Egeland, Ricky [University of Minnesota, Twin Cities (United States); Wildish, Tony [Princeton University (United States); Huang, Chih-Hao [Fermi National Accelerator Laboratory (United States)

    2010-04-01

    The PhEDEx Data Service provides access to information from the central PhEDEx database, as well as certificate-authenticated managerial operations such as requesting the transfer or deletion of data. The Data Service is integrated with the 'SiteDB' service for fine-grained access control, providing a safe and secure environment for operations. A plug-in architecture allows server-side modules to be developed rapidly and easily by anyone familiar with the schema, and can automatically return the data in a variety of formats for use by different client technologies. Using HTTP access via the Data Service instead of direct database connections makes it possible to build monitoring web-pages with complex drill-down operations, suitable for debugging or presentation from many aspects. This will form the basis of the new PhEDEx website in the near future, as well as providing access to PhEDEx information and certificate-authenticated services for other CMS dataflow and workflow management tools such as CRAB, WMCore, DBS and the dashboard. A PhEDEx command-line client tool provides one-stop access to all the functions of the PhEDEx Data Service interactively, for use in simple scripts that do not access the service directly. The client tool provides certificate-authenticated access to managerial functions, so all the functions of the PhEDEx Data Service are available to it. The tool can be expanded by plug-ins which can combine or extend the client-side manipulation of data from the Data Service, providing a powerful environment for manipulating data within PhEDEx.

  10. PhEDEx Data Service

    International Nuclear Information System (INIS)

    The PhEDEx Data Service provides access to information from the central PhEDEx database, as well as certificate-authenticated managerial operations such as requesting the transfer or deletion of data. The Data Service is integrated with the 'SiteDB' service for fine-grained access control, providing a safe and secure environment for operations. A plug-in architecture allows server-side modules to be developed rapidly and easily by anyone familiar with the schema, and can automatically return the data in a variety of formats for use by different client technologies. Using HTTP access via the Data Service instead of direct database connections makes it possible to build monitoring web-pages with complex drill-down operations, suitable for debugging or presentation from many aspects. This will form the basis of the new PhEDEx website in the near future, as well as providing access to PhEDEx information and certificate-authenticated services for other CMS dataflow and workflow management tools such as CRAB, WMCore, DBS and the dashboard. A PhEDEx command-line client tool provides one-stop access to all the functions of the PhEDEx Data Service interactively, for use in simple scripts that do not access the service directly. The client tool provides certificate-authenticated access to managerial functions, so all the functions of the PhEDEx Data Service are available to it. The tool can be expanded by plug-ins which can combine or extend the client-side manipulation of data from the Data Service, providing a powerful environment for manipulating data within PhEDEx.

  11. Influence of pH on the thixotropy of magnesium aluminum hydroxide-kaolinite suspension

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The influence of pH on the thixotropy of pure kaolinite suspension and magnesium alu minum hydroxide (Mg-Al-MMH)-kaolinite suspension was studied. The results show that the thixotropic type of pure kaolinite suspension was not affected by pH studied in the range of 3.60 12.00. The thixotropic type of Mg-Al-MMH-kaolinite suspension with mass ratio (R) value of MMH to kaolinite 0.029 transformed from complex thixotropy into positive thixotropy with increasing of pH in the range of pH 3.83- 12.00, and the type of thixotropy of Mg-AI-MMH-kaolinite suspension with R= 0.129 transformed from positive thixotropy into complex thixotropy with increasing of pH in the range of pH 3.70- 11.96.

  12. Cultivos discontinuos alimentados con urea de la cianobacteria phormidium sp. en función de la salinidad y edad del cultivo

    OpenAIRE

    Lorena del valle Jonte Gómez; Néstor Rosales-Loaiza; José Luis Bermúdez-González; Ever Dario Morales Avendaño

    2013-01-01

    Título en ingles: Urea fed-batch cultures of the cyanobacterium  Phormidium sp. as a function of the salinity and age of cultures Título corto: Cultivos discontinuos alimentados de Phormidium sp.Resumen: Se  Se comparó la eficiencia de sistemas de cultivos discontinuos alimentados versus cultivos discontinuos convencionales, en cuanto a concentración de nitrógeno, adicionando 0,2 mM de urea cada tres días al final de la fase exponencial, durante 21 días. Se realizaron cultivos con un volumen ...

  13. The impact of oxygen consumption by the shrimp Litopenaeus vannamei according to body weight, temperature, salinity and stocking density on pond aeration: a simulation = Impacto do consumo de oxigênio do camarão Litopenaeus vannamei em relação ao peso corporal, temperatura, salinidade na aeração do viveiro: uma simulação

    Directory of Open Access Journals (Sweden)

    Luis Vinatea

    2011-04-01

    Full Text Available A simulation was conducted to determinate the impact caused by thecombination of Litopenaeus vannamei respiratory rate (mg O2 shrimp-1 h-1, the behavior of SOTR (kg O2 h-1 of mechanical aerators as a function of salinity, as well as the oxygen consumption rate of the pond water and soil (mg O2 L-1 h-1 on the aeration of shrimp ponds (1, 10, 50 and 100 ha stocked with different densities (10, 40 and 120 shrimp m-2, salinities (1, 13, 25 and 37 ppt, temperatures (20, 25 and 30°C, and shrimp wet weight (5, 10, 15 and 20 g. Results showed that under lower salinity, with larger shrimp, and higher stocking density, higher will be the quantity of required 2-HP aerators to keep dissolved oxygen over 50% saturation. In addition, under low salinity, with 5 and 10 g shrimp, independent of stocking density, more aerators per hectare are required and electricity cost is higher at 20°C and salinity 1 ppt. Less aerators and lower electricity cost was observed at 30°C, salinities of 25 and 37 ppt, and shrimp of 15 and 20 g. Baseado em estudos de respiração de Litopenaeus vannamei (mg O2 camarão-1 h-1, comportamento do Standard Oxygen Transfer Rate (SOTR, kg O2 h-1 de aeradores mecânicos em função da salinidade, assim como as taxas de respiração da água e do solo (mg O2 L-1 h-1, uma simulação foi realizada a fim de determinar o impacto que estas três variáveis juntas têm sobre a aeração de viveiros (1, 10, 50 e 100 ha, estocados com diferentes densidades (10, 40 e 120 camarões m-2 em salinidades de 1, 13, 25 e 37 ppm, temperaturas de 20, 25 e 30°C e peso úmido dos camarões de 5, 10, 15 e 20 g. Os resultados mostraram que em salinidades mais baixas, com animais maiores e maiores densidades de estocagem, maior será a quantidade de aeradores de 2 cvnecessários para manter o oxigênio dissolvido acima de 50% da saturação. Igualmente, em baixas salinidades e com camarões de 5 e 10 g, independente da densidade de estocagem, mais aeradores

  14. Impacto da salinidade no desenvolvimento e crescimento de mudas de carnaúba (Copernicia prunifera (Miller H.E.Moore Impact of salinity on development and growing of ‘carnaúba’ (Copernicia prunifera (Miller H.E. Moore seedlings

    Directory of Open Access Journals (Sweden)

    Samia J. R. Holanda

    2011-01-01

    Full Text Available Identificar o impacto da salinidade no desenvolvimento e crescimento de espécies resistentes a altas concentrações salinas é de fundamental importância para a recuperação de áreas salinizadas do semiárido nordestino brasileiro. Visando contribuir para a resolução desta problemática, o presente trabalho avaliou o efeito de diferentes níveis de salinidade para o desenvolvimento e o crescimento da carnaúba, espécie nativa e de extremo valor econômico para a região. Os níveis analisados foram: 0, 25, 50, 100 mM de NaCl, correspondente a uma condutividade elétrica de 2.0, 4.6, 7.1, 9.6, 12 dS m-1, respectivamente. Utilizou-se o delineamento inteiramente casualisado, com cinco tratamentos e quatro repetições, e se analisaram as variáveis altura da parte aérea, largura da parte aérea da folha, comprimento da raiz principal, peso da matéria seca, razão da matéria seca parte aérea/raiz e taxa de sobrevivência. Os tratamentos com 25 e 50 mM de NaCl não afetaram a sobrevivência inicial da planta. Concentrações maiores ou iguais que 75 mM de NaCl reduziram a produção de biomassa e a taxa de sobrevivência, em quase 50%; portanto, a produção de plantas nesses níveis de sal não é recomendada.To identify the impact of salinity on the development and growth of species resistant to high salt concentration is fundamental for restoration of salty areas in the Northeast brazilian semi-arid region. Seeking to solve this problem this work evaluated the effect of different salt levels on the development and growth of ‘carnauba’, a native species with high economical value to the region. The levels analyzed were: 0, 25, 50, 75 and 100 mM of NaCl, corresponding to an electrical conductivity of 2.0, 4.6, 7.1, 9.6 and 12 dS m-1, respectively. A completely randomized experimental design with five treatments and four replicates was used. The analyzed variables were aerial height, aerial width, main root length, dry weight, aerial

  15. Concentração salina e fases de exposição à salinidade do meloeiro cultivado em substrato de fibra de coco Salt concentration and phases of exposure tosalinity of melon grown in coconut fiber substrate

    Directory of Open Access Journals (Sweden)

    Nildo da Silva Dias

    2011-09-01

    Full Text Available No semiárido, a escassez de água de boa qualidade faz com que os produtores utilizem água salobra para preparar a solução nutritiva. Com o objetivo de investigar a utilização de água salobra na irrigação de meloeiro (Cucumis melo L., cv. AF 015 cultivado em substrato de fibra de coco em casa de vegetação, plantas foram nutridas com soluções salinas de condutividades elétricas (CEs 1,1 (testemunha; 2,5; 4,0 e 5,5 dS m-1 aplicadas durante as fases: crescimento vegetativo (10-30 dias após o transplantio-DAT; florescimento (31-50 DAT e frutificação e maturação (51-70 DAT. O delineamento experimental foi o inteiramente casualizado, com 12 tratamentos arranjados em um esquema fatorial 4x3 (níveis de salinidade x tempo de exposição dos sais, com três repetições. Houve correlação na perda relativa por incremento de CEs das variáveis de crescimento e de produção do meloeiro em função da salinidade da solução nutritiva para cada fase de exposição. As soluções nutritivas preparadas com água salobra podem ser utilizadas no cultivo do meloeiro em substrato de fibra de coco com o mínimo de perdas relativas de massa média de frutos por incremento de CEs, quando aplicadas na fase de florescimento.Scarcity of good water quality in semiarid region causes producers to use brackish water to prepare the nutrient solution. In order to investigate the use of brackish water in irrigation of greenhouse-melon (Cucumis melo L., cv. AF 015 grown in coconut fiber substrate, plants were irrigated with saltine nutrient solutions of electrical conductivities (ECs of 1.1 (control, 2.5, 4.0 and 5.5 dS m-1, applied during the phases of vegetative growth (10-30 days after transplanting, DAT, flowering (31-50 DAT and fruiting and ripening (51-70 DAT. The design was completely randomized, with 12 treatments arranged in a 4x3 factorial design (salinity levels x exposure time of the salts, with three replications. There was a correlation in

  16. Dynamics of ocular surface pH.

    OpenAIRE

    Coles, W H; Jaros, P A

    1984-01-01

    We studied ocular surface pH in 161 subjects. The mean pH for 133 normal volunteers was 7 . 11, SD 1 . 5. We found that older women had a more alkaline pH than other subjects, that the pH shifted from acid to alkaline during the day, that one hour of eyelid closure caused an acid shift in pH, and that pH recovered to baseline values within 40 minutes after acid drop instillation. We explored the mechanism of pH regulation, and we believe that pH changes could affect contact lens toleration, d...

  17. Determining Critical Soil pH for Grain Sorghum Production

    Directory of Open Access Journals (Sweden)

    Katy Butchee

    2012-01-01

    Full Text Available Grain sorghum (Sorghum bicolor L. has become a popular rotation crop in the Great Plains. The transition from conventional tillage to no-tillage production systems has led to an increase in the need for crop rotations. Some of the soils of the Great Plains are acidic, and there is concern that grain sorghum production may be limited when grown on acidic soils. The objective of this study was to evaluate the effect of soil pH for grain sorghum production. Potassium chloride-exchangeable aluminum was also analyzed to determine grain sorghum’s sensitivity to soil aluminum (Al concentration. The relationship between relative yield and soil pH was investigated at Lahoma, Perkins, and Haskell, Oklahoma, USA with soil pH treatments ranging from 4.0–7.0. Soil pH was altered using aluminum sulfate or hydrated lime. Soil acidity reduced grain sorghum yield, resulting in a 10% reduction in yield at soil pH 5.42. Potassium chloride-exchangeable aluminum levels above 18 mg kg−1 resulted in yield reductions of 10% or greater. Liming should be considered to increase soil pH if it is below these critical levels where grain sorghum will be produced.

  18. Neuronal pH regulation

    DEFF Research Database (Denmark)

    Vorstrup, S; Jensen, K E; Thomsen, C;

    1989-01-01

    The intracellular pH in the brain was studied in six healthy volunteers before and immediately after the administration of 2 g of acetazolamide. Phosphorus-31 nuclear magnetic resonance spectroscopy by a 1.5 tesla whole-body scanner was used. The chemical shift between the inorganic phosphate and...

  19. PhEDEx Data Service

    CERN Document Server

    Egeland, Ricky; Huang, Chih-Hao

    2009-01-01

    The PhEDEx Data Service provides access to information from the central PhEDEx database, as well as certificate-authenticated managerial operations such as requesting the transfer or deletion of data. The Data Service is integrated with the SiteDB service for fine-grained access control, providing a safe and secure environment for operations. A plug-in architecture allows server-side modules to be developed rapidly and easily by anyone familiar with the schema, and can automatically return the data in a variety of formats for use by different client technologies. Using HTTP access via the Data Service instead of direct database connections makes it possible to build monitoring web-pages with complex drill-down operations, suitable for debugging or presentation from many aspects. This will form the basis of the new PhEDEx website in the near future, as well as providing access to PhEDEx information and certificate-authenticated services for other CMS dataflow and workflow management tools such as CRAB, WMCore,...

  20. pH in Action

    NARCIS (Netherlands)

    Tijskens, L.M.M.; Biekman, E.S.A.

    2001-01-01

    Based on fundamental chemical relations, well-established in chemical engineering and chemical technology over almost a century, the effects of pH in food and agricultural products will be deduced for different situations and processes. Based on simple equilibria and dissociation of water, salts, ac

  1. EFECTO DE MÉTODOS DE RIEGO LOCALIZADO EN LA SALINIDAD DEL PERFIL DE SUELO EN VID DE MESA.: CONDUCTIVIDAD ELÉCTRICA, SODIO, CLORO Y BORO EN DISTINTOS PUNTOS DEL PERFIL Effect of micro-irrigation methods on the salinity of the soil profile in a grape vineyard: Electrical conductivity of sodium, chloride and boron at several points of the profile

    OpenAIRE

    Alfonso Osorio U.; Ricardo Césped R.

    2000-01-01

    En un parronal de vid de mesa cv. Thompson Seedless, establecido en suelos aluviales salinos (Aridisoles Paleorthids) del valle de Copiapó, en el norte de Chile, se midió la salinidad del suelo, el contenido de sodio, cloruro y boro, todos en el extracto de saturación. Las muestras se obtuvieron a distintas profundidades, en distintos cortes espaciales en relación a la línea de goteo y a la hilera de plantación, considerando tres tratamientos de riego: línea de goteo con lateral simple, con g...

  2. pH dependent dissolution of sediment aluminum in six Danish lakes treated with aluminum

    DEFF Research Database (Denmark)

    Reitzel, Kasper; Jensen, Henning S.; Egemose, Sara

    2013-01-01

    aluminate in shallow lakes, where resuspension and high pH in the water occurs frequently. In the worst case dissolved Al may reach toxic levels in lakes treated by Al but also the concomitant release of P and the possible loss of dissolved Al to downstream ecosystems are negative effects that may occur......The possible pH dependent dissolution of aluminum hydroxides (Al(OH)(3)) from lake sediments was studied in six lakes previously treated with Al to bind excess phosphorus (P). Surface sediment was suspended for 2 h in lake water of pH 7.5, 8.5, or 9.5 with resulting stepwise increments in dissolved...... Al observed in all lakes. The amount of dissolved Al increased proportional to the sediment content of Al(OH)(3) as quantified by a sequential extraction technique. Up to 24% of the sediment Al(OH)(3) could dissolve within 2 h at pH 9.5 and a portion of sediment P was dissolved concomitantly...

  3. Estudio de laboratorio del efecto de las concentraciones de calcio y caseína, el pH y la temperatura sobre la incorporación de proteínas lácteas al coágulo obtenido por acción enzimática

    Directory of Open Access Journals (Sweden)

    Pires Miryam S.

    1999-01-01

    Full Text Available The effect of casein concentration, Ca2+ concentration, temperature and pH on the amount and size of protein aggregates (fines in the whey produced by enzimic coagulation of nonfat milk was studied in laboratory conditions. Casein concentrations about 0.3 g/L showed a minimal amount of caseins in the whey, with presence of small aggregates of casein micellles. Ca2+ concentrations higher than 5 mM were neccesary to reduce the whey protein to a minimum constituted by protein particles smaller than casein micelles. The coagulation temperature, in the 35 - 45oC range, produced almost no variations in the whey proteins. The obtention of a minimum amount of whey proteins was possible only in a narrow pH range around 6.4. These results pointed to casein concentration and pH as important variables to be controlled in connection with the process yield.

  4. MD-PhD training: looking back and looking forward.

    Science.gov (United States)

    Bonham, Ann C

    2014-01-01

    MD-PhD programs provide rigorous, integrated training for physician-scientists, enabling them to frame scientific questions in unique ways and to apply clinical insight to fundamental science. Few would question the influential contributions of MD-PhD physician-scientists in advancing medical science. In this issue of Academic Medicine, Jeffe et al affirm high levels of excellence in educational outcomes from MD-PhD training programs at U.S. MD-granting medical schools, especially programs that receive funding from the NIH Medical Scientist Training Program (MSTP). The author of this commentary observes that, in the face of current economic pressures, comprehensive, longitudinal national outcomes data from MSTP- and non-MSTP-funded MD-PhD programs will help verify the value provided by MD-PhD physician-scientists. She proposes that MD-PhD programs should better prepare the next generation of physician-scientists for future research environments, which will provide new technologies, venues, and modalities. These research environments will be more closely integrated within health care delivery systems, extend into diverse communities and regions, and employ complex technologies. MD-PhD physician-scientists also will train and gain expertise in broadening areas of research, such as health policy, health economics, clinical epidemiology, and medical informatics. Program leaders are ideally situated to foster innovative learning environments and methodologies. By sharing their innovations, they can help ensure production of a diverse MD-PhD physician-scientist workforce, prepared to engage in myriad research opportunities to meet patient and population needs in a new environment.

  5. AL Amyloidosis

    Directory of Open Access Journals (Sweden)

    Desport Estelle

    2012-08-01

    Full Text Available Abstract Definition of the disease AL amyloidosis results from extra-cellular deposition of fibril-forming monoclonal immunoglobulin (Ig light chains (LC (most commonly of lambda isotype usually secreted by a small plasma cell clone. Most patients have evidence of isolated monoclonal gammopathy or smoldering myeloma, and the occurrence of AL amyloidosis in patients with symptomatic multiple myeloma or other B-cell lymphoproliferative disorders is unusual. The key event in the development of AL amyloidosis is the change in the secondary or tertiary structure of an abnormal monoclonal LC, which results in instable conformation. This conformational change is responsible for abnormal folding of the LC, rich in β leaves, which assemble into monomers that stack together to form amyloid fibrils. Epidemiology AL amyloidosis is the most common type of systemic amyloidois in developed countries with an estimated incidence of 9 cases/million inhabitant/year. The average age of diagnosed patients is 65 years and less than 10% of patients are under 50. Clinical description The clinical presentation is protean, because of the wide number of tissues or organs that may be affected. The most common presenting symptoms are asthenia and dyspnoea, which are poorly specific and may account for delayed diagnosis. Renal manifestations are the most frequent, affecting two thirds of patients at presentation. They are characterized by heavy proteinuria, with nephrotic syndrome and impaired renal function in half of the patients. Heart involvement, which is present at diagnosis in more than 50% of patients, leading to restrictive cardiopathy, is the most serious complication and engages prognosis. Diagnostic methods The diagnosis relies on pathological examination of an involved site showing Congo red-positive amyloid deposits, with typical apple-green birefringence under polarized light, that stain positive with an anti-LC antibody by immunohistochemistry and

  6. Industrial PhD report: Sustainable Innovation

    DEFF Research Database (Denmark)

    Olesen, Gitte Gylling Hammershøj

    2011-01-01

    Erhvervs PhD rapport udarbejdet i tilknytning til Erhvervs PhD kurset der er obligatorisk for Erhvervs PhD studerende. Rapporten omhandler relationer melllem den akademiske verden og industrien i sammenhæng med PhD projektet, betragtet og analyseret gennem teori om bæredygtig innovation....

  7. On Calibration of pH Meters

    OpenAIRE

    Da-Ming Zhu; Cheng, K. L.

    2005-01-01

    The calibration of pH meters including the pH glass electrode, ISE electrodes, buffers, and the general background for calibration are reviewed. Understanding of basic concepts of pH, pOH, and electrode mechanism is emphasized. New concepts of pH, pOH, as well as critical examination of activity, and activity coefficients are given. The emergence of new solid state pH electrodes and replacement of the salt bridge with a conducting wire have opened up a new horizon for pH measurements. A pH bu...

  8. The Methods Behind PH WINS.

    Science.gov (United States)

    Leider, Jonathon P; Bharthapudi, Kiran; Pineau, Vicki; Liu, Lin; Harper, Elizabeth

    2015-01-01

    The Public Health Workforce Interests and Needs Survey (PH WINS) has yielded the first-ever nationally representative sample of state health agency central office employees. The survey represents a step forward in rigorous, systematic data collection to inform the public health workforce development agenda in the United States. PH WINS is a Web-based survey and was developed with guidance from a panel of public health workforce experts including practitioners and researchers. It draws heavily from existing and validated items and focuses on 4 main areas: workforce perceptions about training needs, workplace environment and job satisfaction, perceptions about national trends, and demographics. This article outlines the conceptualization, development, and implementation of PH WINS, as well as considerations and limitations. It also describes the creation of 2 new data sets that will be available in public use for public health officials and researchers--a nationally representative data set for permanently employed state health agency central office employees comprising over 10,000 responses, and a pilot data set with approximately 12,000 local and regional health department staff responses. PMID:26422490

  9. Influence of pH on Formation of Taranakites

    Institute of Scientific and Technical Information of China (English)

    ZHOUJIANMIN; P.M.HUANG

    1999-01-01

    Monoammonium phosphate(1 mol L-1),monopotassium phosphate(1 mol L-1) and aluminum chloride(5×10-3molL-1)were used to investigate the influence of pH on the formation of NH4-taranakite and K-taranakite in systems with a high NH4H2PO4 or KH2PO4 concentration.The experimental data indicated that the reaction products of aluminum with NH4H2PO4 or KH2PO4 changed with the pH in the systems.In a pH range of 2.5 to 10.0,as the pH increased,the products in either ammonium or potassium system followed the sequence:taranakite,amorphous(NH4,K)2AIH(PO4)2.4H2O,and then crystalline (NH4,K)AlPO4OH.2H2O.However,the pH ranges of the formation of these products in ammonium system were different from potassium system.NH4-taranakite formed from pH 2.75 to pH 5.75,whereas K-taranakite formed in the pH range of 3.00 to 5.0,From the theoretical calcuation by a computer program (GEOCHEM version 2.0) ,NH4-taranakte and K-taranakite could form at the pH from 1.50 to 8.30 and from 1.25to 8.45,respectively.These pH ranges were much wider than the experimental results.The difference between the experimental data and theoretical data was attributed to the lack of kinetic data and /or the incompleteness and inaccuracy of the thermodynamic data in the data base of the program.The pH ranges of the formation of the taranakites indicated that the taranakites could exist in the immediate vicinity of phosphate ferilizer zone as reaction products of phosphate fertilizers with soils,especially acideic soils,resulting in the fixation of not only phosphate but also nitrogen and /or potassium in soils.

  10. pH, alkalinity, temperature, salinity and other variables collected from time series profile observations using Alkalinity titrator, CTD and other instruments from the Al Amir Moulay Abdellah in the North Atlantic Ocean and Strait of Gibraltar from 2005-05-04 to 2007-05-08 (NODC Accession 0112928)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NODC Accession 0112928 includes chemical, discrete sample, physical and time series profile data collected from Al Amir Moulay Abdellah in the North Atlantic Ocean...

  11. Reduction of exchangeable calcium and magnesium in soil with increasing pH

    Directory of Open Access Journals (Sweden)

    Miyazawa Mário

    2001-01-01

    Full Text Available A laboratory study was conducted with soil samples and synthetic solutions to investigate possible mechanisms related with reduction in KCl exchangeable Ca and Mg with increasing pH. Increasing soil pH over 5.3 with CaCO3 added to the soil and with NaOH solution added to soil/KCl suspension increased adsorptions of Ca and Mg. The reduction of Mg was greater than Ca and was related to the concentration of soil exchangeable Al. The decreases of soluble Ca and Mg following addition of Al in synthetic solution were at pH > 7.5. The isomorphic coprecipitation reaction with Al compounds may be the most possible mechanism responsible for the decrease of exchangeable Ca and Mg with increasing pH. Possible chemical reactions are presented.

  12. Níveis de salinidade e manejo da fertirrigação sobre características da berinjela cultivada em ambiente protegido Levels of salinity and fertigation management on the characteristics of the eggplant when grown in a protected environment

    Directory of Open Access Journals (Sweden)

    Everaldo Moreira da Silva

    2013-03-01

    Full Text Available Objetivou-se estudar os efeitos de diferentes níveis de salinidade do solo sobre as variáveis fenológicas e de produção da berinjela, cultivada em vasos e em ambiente protegido. O estudo foi conduzido na área experimental do Departamento de Engenharia de Biossistemas da ESALQ/USP, Piracicaba, SP. Os tratamentos foram compostos da combinação de dois fatores: 6 níveis de salinidade inicial do solo (S1 = 1,3; S2 = 2,4; S3 = 3,6; S4 = 4,5; S5 = 5,6 e S6 = 6,4 dS m-1 e dois manejos de fertirrigação: com controle da condutividade elétrica da solução do solo (M1, e o tradicional (M2, obedecendo a curva de absorção de nutrientes da cultura. O delineamento estatístico adotado foi o de blocos casualizados completos, com quatro repetições, arranjados no esquema fatorial 6 x 2. Os resultados revelaram que os níveis de salinidade do solo afetaram diretamente as variáveis, produção de matéria seca, produção de frutos e índice de área foliar das plantas. Verificou-se que a redução média na produção da cultura da berinjela, em estufa, foi da ordem de 8,65% para o incremento de 1 dS m-1 na salinidade do solo, acima da salinidade limiar, que foi de 1,71 dS m-1.The objective was to study the effects of different levels of soil salinity on the phenological variables and production of the eggplant when grown in pots in a protected environment. The study was carried out at the experimental site of the Department of Biosystems Engineering ESALQ/USP in Piracicaba, São Paulo. The treatments consisted of a combination of two factors: six initial levels of soil salinity (S1 = 1.3, S2 = 2.4, S3 = 3.6, S4 = 4.5, S5 = 5.6 and S6 = 6.4 dS m-1 and two fertigation management: with the electrical conductivity of the soil solution being controlled (M1 and traditional (M2, following the absorption curve of nutrients from the culture. The statistical design adopted was a randomized complete-block design with four replications, arranged in a 6 x 2

  13. Crescimento de mudas de moringa em função da salinidade da água e da posição das sementes nos frutos Growth of moringa seedlings as function of salinity and seed position in the fruits

    Directory of Open Access Journals (Sweden)

    Francisco de Assis de Oliveira

    2013-02-01

    Full Text Available A escolha das sementes é de fundamental importância para a obtenção de mudas de qualidade, principalmente quando são produzidas sob condições ambientais adversas. Este trabalho foi desenvolvido com o objetivo de avaliar a influencia da salinidade sobre o desenvolvimento de mudas de moringa provenientes de sementes localizadas em diferentes posiç��es no fruto. O delineamento utilizado foi o inteiramente casualizado, com os tratamentos arranjados em esquema fatorial 3 x 4 e quatro repetições. Os tratamentos resultaram da combinação de três posições de sementes no fruto (basal, mediana e apical com quatro níveis de salinidade da água de irrigação (0,5; 2,0; 3,5; e 5,0 dS m-1. Foram avaliadas as seguintes características de crescimento: altura (ALT, diâmetro do caule (DC, diâmetro da raiz principal (DRP, número de folhas (NF, área foliar (AF, massa seca da parte aérea (MSPA, massa seca do sistema radicular (MSR e massa seca total (MST. Os dados foram submetidos à análise de variância pelo teste F e as médias, comparadas pelo teste de Tukey a 5% de probabilidade, para o efeito da posição da semente no fruto; e por análise de regressão, para os dados provenientes da salinidade. Houve interação significativa na maioria das características avaliadas. A salinidade da água de irrigação diminuiu em todas as variáveis. As mudas provenientes de sementes localizadas na porção basal dos frutos foram mais afetadas pela salinidade da água de irrigação.Choosing seeds is crucial for obtaining good quality seedlings, especially when the seedlings are grown under adverse environmental conditions. This work was carried out to evaluate the influence of salinity on the development of moringa seedlings from seeds located at different positions in the pod. The design used in this study was a completely randomized design with treatments arranged in 3 x 4 factorial scheme, with four replications. The treatments resulted from

  14. Variabilidade espacial de classes de textura, salinidade e condutividade hidráulica de solos em planície aluvial Spatial variability of textural classes, salinity and hydraulic conductivity of soil in an alluvial plain

    Directory of Open Access Journals (Sweden)

    Abelardo A. A. Montenegro

    2006-03-01

    Full Text Available Visando-se avaliar a distribuição de classes texturais e sua correlação espacial com a infiltrabilidade e salinidade de uma área aluvial, no Agreste de Pernambuco, utilizou-se a geoestatística indicadora segundo uma distribuição binária baseada na presença/ausência de solos francos. Considerando-se pontos de amostragem e de testes de infiltração dispostos ao longo do eixo principal do aluvião, e aleatoriamente distribuídos, analisou-se a variabilidade espacial das classes de solo predominantes, da velocidade de infiltração básica (condutividade hidráulica saturada e da condutividade elétrica do extrato de saturação da camada subsuperficial, cujos alcances dos semi-variogramas ajustados foram de 333, 320 e 520 m, respectivamente. Verificou-se que a geoestatística indicadora preservou a correlação espacial entre a textura e a condutividade hidráulica, e entre a textura e a condutividade elétrica. Deste modo, as classes de solo predominantes podem ser usadas para representar distintos padrões no tocante ao potencial de lixiviação e à susceptibilidade de salinização. A metodologia indicadora mostra-se promissora para estudo da variabilidade espacial de propriedades físicas de solos aluviais onde predominam classes contrastantes.Aiming to evaluate the soil textural classes distribution and the spatial correlation between the soil textural classes and both infiltration rate and salinity in an alluvial area, in Pernambuco State "agreste" region, indicator geostatistics has been applied, adopting a binary distribution based on the presence/absence of loam soils. Considering sampling points and test locations along the main longitudinal transect in the valley, as well as randomly distributed locations, the spatial variability of the main soil classes, the infiltration rate, and the electrical conductivity of the saturated extract have been analyzed, for the subsurface soil layer. The fitted semivariogram ranges were 333

  15. Anerkennung als Voraussetzung gesellschaftlicher und unternehmerischer Teilhabe

    OpenAIRE

    Eurich, Johannes; Brink, Alexander

    2003-01-01

    Angesichts des neuen Phänomens der sozialen Exklusion wird soziale Gerechtigkeit nicht mehr nur über die Verteilung von Gütern hergestellt, vielmehr spielt auch die Ebene der Partizipation eine Rolle. Anerkennung ist eine Grundvoraussetzung für Partizipation. Die Verfasser diskutieren Fragen der Unternehmensethik auf der Dimension der Anerkennung. Sie votieren für ein normatives Stakeholder-Management als freiwillige Verpflichtung, das auch strategischen Anforderungen gerecht werden kann. Als...

  16. Seawater pH at the advent of metazoan calcification

    Science.gov (United States)

    Ries, Justin; Gonzalez-Roubaud, Cécile; Douville, Eric; Montagna, Paolo

    2016-04-01

    The boron isotopic composition (δ11B) of bulk limestones provides a potentially powerful tool for reconstructing seawater pH deep into the geologic past (Kasemann et al., 2005; Paris et al., 2010; Ohnemueller et al., 2014). Here, we present δ11B of 35 calcitic limestones derived from a ca. 9 m.y. interval of the terminal Proterozoic Nama Group of southern Namibia. These units immediately precede the so-called Cambrian Radiation - the greatest diversification of metazoans in Earth history marked by the near-simultaneous advent of calcification across most animal phyla. The Nama Group represents one of the best preserved (average [Sr] = 1805 ppm; Mn/Sr -10‰) and most continuous terminal Proterozoic limestone sequences known in the world. The carbonate units investigated here were deposited between ca. 552 and 543 Ma in a semi-divided foreland basin of the Kalahari Craton (Grotzinger and Miller, 2008). Depositional environments were shore-associated and ranged from upper shoreline/tidal flats to below-wave-base lower shoreface, and comprise calcisiltites, calcarenites, heterolithic interbeds, grainstones, and microbialites (Saylor et al., 1998; Grotzinger and Miller, 2008). The δ11B of the 35 sampled Nama Group carbonates were obtained via MC-ICP-MS. Samples were screened for contamination of the δ11B signal by clays (using [Al] as a proxy for clay content) (Paris et al., 2010) and by open-system meteoric diagenesis (δ11B-δ18O correlation). The δ11B values of the limestones ranged from 0.5 to 10.8‰ (avg. = 5.3‰), which is consistent with the previously observed increasing trend in carbonate δ11B (Paris et al., 2010) from the -6.2 to 2.7‰ values reported for Neoproterozoic cap carbonate dolostones (Kasemann et al., 2005) to the ca. 25‰ value reported for most modern marine carbonates. B/Ca ratios for the sampled limestones ranged from 3.4 to 24.0 ppm (avg. = 11.0). Assuming a seawater temperature of 25° C, a salinity of 35, a depth of 10 m, a

  17. Corrosion of Mechanically Alloyed Nanostructured FeAl Intermetallic Powders

    OpenAIRE

    Torres-Islas, A.; C. Carachure; Serna, S.; B. Campillo; G. Rosas

    2012-01-01

    The corrosion behavior of the Fe40Al60 nanostructured intermetallic composition was studied using electrochemical impedance spectroscopy (EIS) and linear polarization resistance (LPR) techniques with an innovative electrochemical cell arrangement. The Fe40Al60 (% at) intermetallic composition was obtained by mechanical alloying using elemental powders of Fe (99.99%) and Al (99.99%). All electrochemical testing was carried out in Fe40Al60 particles that were in water with different pH values. ...

  18. Coping with PH over the Long Term

    Science.gov (United States)

    ... Siblings Cope Parents Weigh in on Sibling Issues Co-Parenting a Child with PH You and Your Partner: ... Siblings Cope Parents Weigh in on Sibling Issues Co-Parenting a Child with PH You and Your Partner: ...

  19. pH sensor calibration procedure

    OpenAIRE

    Artero Delgado, Carola; Nogueras Cervera, Marc; Manuel Lázaro, Antonio; Prat Tasias, Jordi; Prat Farran, Joana d'Arc

    2013-01-01

    This paper describes the calibration of pH sensor located at the OBSEA marine Observatory. This instrument is based on an industrial pH electrode that is connected to a CTD instrument (Conductivity, Temperature, and Depth ). The calibration of the pH sensor has been done using a high precision spectrophotometer pH meter from Institute of Marine Sciences (ICM), and in this way it has been obtained a numerical function for the p H sensor propor...

  20. PhD students and integrative research

    NARCIS (Netherlands)

    Fry, G.; Tress, B.; Tress, G.

    2006-01-01

    The training of PhD students is currently very dynamic and varies widely from place to place. We present some examples of this variation and comment on how it may affect the way PhD students cope with integrative studies. Our focus is on the training needs of PhD students studying integrative resear

  1. Enhancing phosphate adsorption by Mg/Al layered double hydroxide functionalized biochar with different Mg/Al ratios.

    Science.gov (United States)

    Li, Ronghua; Wang, Jim J; Zhou, Baoyue; Awasthi, Mukesh Kumar; Ali, Amjad; Zhang, Zengqiang; Gaston, Lewis A; Lahori, Altaf Hussain; Mahar, Amanullah

    2016-07-15

    Mg/Al ratio plays a significant role for anion adsorption by Mg/Al-layered double hydroxides (Mg/Al-LDHs) modified biochar. In this study, Mg/Al-LDHs biochar with different Mg/Al ratios (2, 3, 4) were prepared by co-precipitation for phosphate removal from aqueous solution. Factors on phosphate adsorption including Mg/Al ratio, pH, and the presence of other inorganic anions were investigated through batch experiments. Increasing Mg/Al ratio in the Mg/Al-LDHs biochar composites generally enhanced phosphate adsorption with Langmuir adsorption maximum calculated at 81.83mg phosphorous (P) per gram of 4:1Mg/Al-LDHs biochar at pH3.0. The adsorption process was best described by the pseudo-second-order kinetic model. Solution pH had greater effects on the phosphate adsorption by Mg/Al LDHs biochar composites with lower Mg/Al ratios. The presence of other inorganic anions decreased the phosphate adsorption efficiency in the order of F(-) > SO4(2-) > NO2(-) >Cl(-). Phosphate adsorption mechanism involves ion exchange, electrostatic attraction and surface inner-sphere complex formation. Overall, Mg/Al-LDHs biochar composites offer a potential alternative of carbon-based adsorbent for phosphate removal from aqueous solution. PMID:27058131

  2. Acidez potencial pelo método do pH SMP no Estado do Amazonas Potential acidity by pH SMP method in Amazonas State, Brazil

    Directory of Open Access Journals (Sweden)

    Adônis Moreira

    2004-01-01

    Full Text Available O objetivo deste trabalho foi definir um modelo matemático que estime o H+Al a partir do pH SMP medido em água e em solução de CaCl2 0,01 mol L-1 nas condições edafoclimáticas locais. Foram utilizadas 246 amostras de solo provenientes de diversas localidades. Mesmo apresentando menor coeficiente da correlação (r = 0,89*, a equação H+Al = 30,646 - 3,848pH SMP obtida em H2O foi mais eficiente que a obtida em solução CaCl2 (H+Al = 30,155 - 3,834pH SMP, r = 0,91*, a qual subestima os valores da acidez potencial.The objective of this work was to determine a mathematic model that estimates the potential acidity with pH SMP measured in water and in solution of CaCl2 0.01 mol L-1. Two hundred and forty six soil samples from several localities were utilized. Despite presenting a lower correlation coefficient (r = 0.89*, the equation H+Al = 30.646 - 3.848pH SMP, obtained in H2O, was more efficient than in the CaCl2 solution (H+Al = 30.155 -3.834pH SMP, r = 0.91*, since this last one underestimates the values of the potential acidity.

  3. Aluminium impact on freshwater invertebrates at low pH: A review

    Science.gov (United States)

    Herrmann, Jan

    The state of knowledge on aluminium (Al) impact on freshwater invertebrates at low pH is reviewed. Mainly inorganic ions seem to be biologically harmful. Published effect/mechanism descriptions may seem somewhat contradictory, but this can be due to the heterogeneity of "the invertebrate group", as well as the multitude and complexity of occurring Al species, thereby also Al analysis problems. Addition of Al to streams has in some cases increased drift and death of mainly some "surface-dependent" species (chironomids, mayflies, dance flies, dixid midges), but also some strictly benthic animals (isopods, stoneflies), while other studies on a variety of animals do not record any change in neither drift, mortality nor biomass. In laboratory exposures Al has been shown to cause raised mortality for some daphnids and blackfly larvae at pH around 5; in the latter animals the effect was however mitigated by humus. A variety of other freshwater invertebrates were not affected. Moreover, at pH 4, Al has even been shown to improve the survival of mayfly nymphs and daphnids, otherwise impaired by the low pH in itself. The reason for this is not clear. Proofs for "food chain accumulation" of Al are still weak. Very high additions of Al have caused a decreased respiration rate in a dragonfly nymph, while a more field-relevant exposure level increased respiration in mayfly nymphs. This suggests a stress situation, probably due to impaired osmoregulation, indicating chemical or mechanical Al impact. The lowered oxygen uptake is then compensated for by improved respiration rate. A model for this is presented. Studies on crayfish, daphnids, mayflies and waterbugs indicate that Al can lower osmoregulatory efficiency and thereby affect the ion balance maintaining mechanisms of the animals. Such sublethal effects are important and should be studied further. The review also critically discusses the concepts mortality and bioavailability.

  4. Uranium-induced oxidative stress in Arabidopsis thaliana: influence of pH on uranium toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Horemans, N.; Saenen, E.; Vanhoudt, N.; Vandenhove, H.; Biermans, G.; Van Hees, M. [SCK.CEN (Belgium); Vangronsveld, J.; Cuypers, A. [Hasselt University (Belgium)

    2014-07-01

    Chemical toxicity of uranium (U) is dependent on U speciation. An important factor controlling the speciation is the environmental pH level. While U uptake and translocation at different pH levels has been reported by several authors (Ebbs et al. 1998, Laurette et al. 2012), little information is available on the cellular responses after U exposure under contrasted chemical speciation conditions. Therefore, the main objective of this study includes the influence of the medium pH on U toxicity and the mechanisms that are involved herein. Hydroponically grown Arabidopsis thaliana plants were exposed to different U concentrations during 3 days at pH 4.5 or pH 7.5. Exposing Arabidopsis thaliana roots to U resulted in a significant decrease in fresh weight at both pH levels. The effective concentration that caused 50% growth reduction (EC50) at pH 4.5 (28 ± 1.5 μM U) was approximately 2.5 times lower than the EC50 value observed at pH 7.5 (70 ± 10 μM U). This may indicate that U is more toxic at low pH. In addition, the difference can be explained by the fact that for similar nominal U concentrations, U was more readily taken up by the roots at low pH, possibly leading to more adverse effects. The anti-oxidative defence mechanisms that were activated after U exposure were similar at both pH levels, although the activation occurred at lower U concentrations at pH 4.5 as compared to pH 7.5. For example, microRNA398b/c was activated under U stress. This microRNA post-transcriptionally regulates the expression of copper/zinc superoxide dismutases, enzymes important in scavenging reactive oxygen species (ROS). As such, a significant increase in the MIR398b/c transcript levels was observed at pH 4.5 after exposure to 50 μM U, while at pH 7.5 a significant induction was only observed after exposure to 100 μM U. Although the U concentration in the leaves was low, the U translocation at pH 4.5 was approximately 3 times lower than the translocation found at pH 7.5. However

  5. Influence of pH on Nanofluids' Viscosity and Thermal Conductivity

    Institute of Scientific and Technical Information of China (English)

    WANG Xian-Ju; LI Xin-Fang

    2009-01-01

    Aiming at the dispersion stability of nanoparticles regarded as the guide of heat transfer enhancement, we investigate the viscosity and the thermal conductivity of Cu and Al2O3 nanoparticles in water under different pH values. The results show that there exists an optimal pH value for the lowest viscosity and the highest thermal conductivity, and that at the optimal pH value the nanofluids containing a small amount of nanoparticles have noticeably higher thermal conductivity than that of the base fluid without nanoparticles. For the two nanofluids the enhancements of thermal conductivity are observed up to 13% (Al2Oa-water) or 15% (Cu-water) at 0.4 wt%,respectively. Therefore, adjusting the pH values is suggested to improve the stability and the thermal conductivity for practical applications of nanofluid.

  6. Competitive and synergistic effects in pH dependent phosphate adsorption in soils: LCD modeling.

    Science.gov (United States)

    Weng, Liping; Vega, Flora Alonso; Van Riemsdijk, Willem H

    2011-10-01

    The pH dependency of soluble phosphate in soil was measured for six agricultural soils over a pH range of 3-10. A mechanistic model, the LCD (ligand charge distribution) model, was used to simulate this change, which considers phosphate adsorption to metal (hydr)oxides in soils under the influence of natural organic matter (NOM) and polyvalent cations (Ca(2+), Al(3+), and Fe(3+)). For all soils except one, the description in the normal pH range 5-8 is good. For some soils at more extreme pH values (for low P-loading soils at low pH and for high P-loading soils at high pH), the model over predicts soluble P. The calculation shows that adsorption is the major mechanism controlling phosphate solubility in soils, except at high pH in high P-loading soils where precipitation of calcium phosphate may take place. NOM and polyvalent cations have a very strong effect on the concentration level of P. The pattern of pH dependency of soluble P in soils differs greatly from the pH effects on phosphate adsorption to synthetic metal (hydr)oxides in a monocomponent system. According to the LCD model, the pH dependency in soil is mainly caused by the synergistic effects of Ca(2+) adsorption to oxides. Adsorption of Al(3+) to NOM adsorbed plays an important role only at a pH < 4.5. Presence of NOM coating strongly competes with phosphate for the adsorption and is an important factor to consider in modeling phosphate adsorption in natural samples.

  7. Dynamic regulation of gastric surface pH by luminal pH

    OpenAIRE

    Chu, Shaoyou; Tanaka, Shin; Kaunitz, Jonathan D.; Montrose, Marshall H.

    1999-01-01

    In vivo confocal imaging of the mucosal surface of rat stomach was used to measure pH noninvasively under the mucus gel layer while simultaneously imaging mucus gel thickness and tissue architecture. When tissue was superfused at pH 3, the 25 μm adjacent to the epithelial surface was relatively alkaline (pH 4.1 ± 0.1), and surface alkalinity was enhanced by topical dimethyl prostaglandin E2 (pH 4.8 ± 0.2). Luminal pH was changed from pH 3 to pH 5 to mimic the fasted-to-fed transition in intra...

  8. Comportamento de mudas de nim à salinidade da água em solo não salino com biofertilizante Behavior of neem seedlings under water salinity in a non-saline soil with biofertilizer application

    Directory of Open Access Journals (Sweden)

    Járisson C. Nunes

    2012-11-01

    Full Text Available Um experimento foi desenvolvido em ambiente telado do Departamento de Solos e Engenharia Rural da Universidade Federal da Paraíba, Areia, PB, no período de janeiro a abril de 2010. O substrato constou de material de um Neossolo Quartzarênico não salino, coletado na camada de 0-20 cm. Os tratamentos foram dispostos em delineamento inteiramente casualizado em esquema fatorial 5 x 2, referente aos níveis de salinidade da água de irrigação de 0,5; 1,0; 2,0; 3,0 e 4,0 dS m-1, no solo sem e com biofertilizante comum, aplicado ao solo uma única vez, após diluição em água, na proporção de 1:1, um dia antes da semeadura, em volume correspondente a 10% do volume do substrato. Aos 86 dias após a emergência das plântulas normais avaliaram-se o crescimento em altura e o comprimento da raiz, diâmetro do caule e da raiz, número de folhas e a massa seca das raízes e parte aérea das plantas. O conteúdo salino da água de irrigação elevou a condição salina do substrato ao ponto de comprometer o crescimento em altura e diâmetro do caule, número de folhas, diâmetro e comprimento da raiz principal, massa seca das raízes e parte aérea (folhas + caule do nim mas com declínios menos pronunciados nos tratamentos com biofertilizante bovino.An experiment was carried out in greenhouse during the period January to April 2010, at Center of Agricultural Sciences of the Federal University of Paraiba, in Areia, Paraiba State, Brazil, in order to evaluate the effects of saline water and bovine biofertilizer on the seedling growth of Indian neem. The substrate was material of a non-saline soil collected in depth of 0-20 cm. The treatments were arranged in a completely randomized design using a 5 x 2 factorial, referring to salinity levels of irrigation water of 0.5, 1.0, 2.0, 3.0 and 4.0 dS m-1, with and without bovine biofertilizer applied to the soil only once after dilution with water (1:1, a day before sowing, in volume corresponding to 10% of

  9. Functional photoacoustic microscopy of pH

    Science.gov (United States)

    Chatni, M. Rameez; Yao, Junjie; Danielli, Amos; Favazza, Christopher P.; Maslov, Konstantin I.; Wang, Lihong V.

    2012-02-01

    pH is a tightly regulated indicator of metabolic activity. In mammalian systems, imbalance of pH regulation may result from or result in serious illness. Even though the regulation system of pH is very robust, tissue pH can be altered in many diseases such as cancer, osteoporosis and diabetes mellitus. Traditional high-resolution optical imaging techniques, such as confocal microscopy, routinely image pH in cells and tissues using pH sensitive fluorescent dyes, which change their fluorescence properties with the surrounding pH. Since strong optical scattering in biological tissue blurs images at greater depths, high-resolution pH imaging is limited to penetration depths of 1mm. Here, we report photoacoustic microscopy (PAM) of commercially available pH-sensitive fluorescent dye in tissue phantoms. Using both opticalresolution photoacoustic microscopy (OR-PAM), and acoustic resolution photoacoustic microscopy (AR-PAM), we explored the possibility of recovering the pH values in tissue phantoms. In this paper, we demonstrate that PAM was capable of recovering pH values up to a depth of 2 mm, greater than possible with other forms of optical microscopy.

  10. Variación estacional e influencia de la turbidez y la salinidad sobre el zooplancton de un lago salino de la región central de Argentina Seasonal variation and influence of turbidity and salinity on the zooplankton of a saline lake in central Argentina

    Directory of Open Access Journals (Sweden)

    Santiago Andrés Echaniz

    2011-07-01

    Full Text Available The limnology of saline water bodies at other latitudes is fairly well known, but in Argentina such studies have only recently begun. The applicability of many conclusions regarding the functioning of these environments around the world is limited due to the scant ecological knowledge of some endemic species recorded in the assemblages of Argentine lakes. The aims of this work were to determine the effects of salinity and inorganic turbidity on the taxonomic composition, abundance, and zooplankton biomass in a shallow, hypereutrophic, mesosaline lake in the north of La Pampa province characterized by seasonality, variations in level and salinity, and the lack of macrophytes and fishes, and to compare it with other shallow lakes of the province. We found important differences with other saline lakes: the species richness was lower; the mean abundance of zooplankton was between four and six times higher; and rotifers, which were not affected by salinity or the concentration of inorganic suspended solids, were numerically predominant. Crustaceans, on the other hand, were negatively affected by these environmental factors. Biomass was twofold higher than that recorded in the same period in two shallow lakes of Pampa, with similar nutrient concentrations but lower salinities.La limnología de los cuerpos de agua salinos de otras latitudes es bastante conocida, pero en Argentina se ha comenzado a estudiar recientemente. Muchas conclusiones sobre el funcionamiento de estos ambientes a nivel mundial son de aplicación restringida debido a que las asociaciones registradas en los lagos argentinos tienen algunas especies endémicas, cuyo conocimiento ecológico es escaso. Los objetivos de este trabajo fueron determinar los efectos de la salinidad y la turbidez inorgánica sobre la composición taxonómica, abundancia y biomasa zooplanctónica en un lago somero mesosalino hipereutrófico del norte de La Pampa, caracterizado por su temporalidad, variaciones

  11. Produção de melão Pele de Sapo híbrido 'Medellín' cultivado com diferentes salinidades da água Production of the hybrid Pele-de-Sapo melon Medellín cultivated at different water salinities

    Directory of Open Access Journals (Sweden)

    Damiana Cleuma de Medeiros

    2011-09-01

    Full Text Available Dentre os problemas enfrentados pela cultura do melão no Estado do Rio Grande do Norte, a salinidade da água e do solo é um dos principais fatores limitantes da produção e da qualidade dos frutos. O objetivou-se com este trabalho estudar os efeitos de aplicação de águas de irrigação com diferentes níveis de salinidade na produção de melão Pele de Sapo híbrido 'Medellín'. O delineamento utilizado foi o de blocos inteiramente casualizados com quatro repetições. Os tratamentos constaram de concentrações de sais na água de irrigação (0,54; 1,48; 2,02; 3,03 e 3,9 dS m-1. As características de produção avaliadas foram: produtividade comercial e produtividade total, número de frutos comerciais por planta, número de frutos totais, massa média de frutos comerciais, massa média dos frutos totais. O incremento da salinidade na água influenciou negativamente o rendimento da cultura, com perdas relativas por incremento unitário de salinidade acima de 0,54 dS m-1, de 7,5%; 7,8%; 8,32% e 8,70%, para produtividade comercial e total e número de frutos comerciais e totais, respectivamente.Among the problems facing cultivation of the melon in the State of Rio Grande do Norte, the salinity of the water and soil is a major limiting factor of both production and fruit quality. The objective of this work was to study the effects on the production of the hybrid Pele-de-Sapo melon Medellin, of irrigation waters at different salinity levels. The experimental design was a completely randomized block with four replications, with treatments consisting of different salt-concentrations in the irrigation water (0.54; 1.48; 2.02; 3.03 and 3.9 dS m-1. The production features measured were: total yield and commercial yield; total number of marketable fruits per plant; total number of fruits; mean weight of the marketable fruits, and total mean weight of the fruits. The increase in water salinity negatively affected the crop yield, with relative

  12. Aluminum elution and precipitation in glass vials: effect of pH and buffer species.

    Science.gov (United States)

    Ogawa, Toru; Miyajima, Makoto; Wakiyama, Naoki; Terada, Katsuhide

    2015-02-01

    Inorganic extractables from glass vials may cause particle formation in the drug solution. In this study, the ability of eluting Al ion from borosilicate glass vials, and tendencies of precipitation containing Al were investigated using various pHs of phosphate, citrate, acetate and histidine buffer. Through heating, all of the buffers showed that Si and Al were eluted from glass vials in ratios almost the same as the composition of borosilicate glass, and the amounts of Al and Si from various buffer solutions at pH 7 were in the following order: citrate > phosphate > acetate > histidine. In addition, during storage after heating, the Al concentration at certain pHs of phosphate and acetate buffer solution decreased, suggesting the formation of particles containing Al. In citrate buffer, Al did not decrease in spite of the high elution amount. Considering that the solubility profile of aluminum oxide and the Al eluting profile of borosilicate glass were different, it is speculated that Al ion may be forced to leach into the buffer solution according to Si elution on the surface of glass vials. When Al ions were added to the buffer solutions, phosphate, acetate and histidine buffer showed a decrease of Al concentration during storage at a neutral range of pHs, indicating the formation of particles containing Al. In conclusion, it is suggested that phosphate buffer solution has higher possibility of forming particles containing Al than other buffer solutions.

  13. Aluminum elution and precipitation in glass vials: effect of pH and buffer species.

    Science.gov (United States)

    Ogawa, Toru; Miyajima, Makoto; Wakiyama, Naoki; Terada, Katsuhide

    2015-02-01

    Inorganic extractables from glass vials may cause particle formation in the drug solution. In this study, the ability of eluting Al ion from borosilicate glass vials, and tendencies of precipitation containing Al were investigated using various pHs of phosphate, citrate, acetate and histidine buffer. Through heating, all of the buffers showed that Si and Al were eluted from glass vials in ratios almost the same as the composition of borosilicate glass, and the amounts of Al and Si from various buffer solutions at pH 7 were in the following order: citrate > phosphate > acetate > histidine. In addition, during storage after heating, the Al concentration at certain pHs of phosphate and acetate buffer solution decreased, suggesting the formation of particles containing Al. In citrate buffer, Al did not decrease in spite of the high elution amount. Considering that the solubility profile of aluminum oxide and the Al eluting profile of borosilicate glass were different, it is speculated that Al ion may be forced to leach into the buffer solution according to Si elution on the surface of glass vials. When Al ions were added to the buffer solutions, phosphate, acetate and histidine buffer showed a decrease of Al concentration during storage at a neutral range of pHs, indicating the formation of particles containing Al. In conclusion, it is suggested that phosphate buffer solution has higher possibility of forming particles containing Al than other buffer solutions. PMID:24261406

  14. Effect of operational pH on biohydrogen production from food waste using anaerobic batch reactors.

    Science.gov (United States)

    Lee, Chaeyoung; Lee, Sewook; Han, Sun-Kee; Hwang, Sunjin

    2014-01-01

    This study was performed to investigate the influence of operational pH on dark H(2) fermentation of food waste by employing anaerobic batch reactors. The highest maximum H(2) yield was 1.63 mol H(2)/mol hexoseadded at operational pH 5.3, whereas the lowest maximum H(2) yield was 0.88 mol H(2)/mol hexoseadded at operational pH 7.0. With decreasing operational pH values, the n-butyrate concentration tended to increase and the acetate concentration tended to decrease. The highest hydrogen conversion efficiency of 11.3% was obtained at operational pH 5.3, which was higher than that (8.3%) reported by a previous study (Kim et al. (2011) 'Effect of initial pH independent of operational pH on hydrogen fermentation of food waste', Bioresource Technology 102 (18), 8646-8652). The new result indicates that the dark fermentation of food waste was stable and efficient in this study. Fluorescence in situ hybridization (FISH) analysis showed that Clostridium species Cluster I accounted for 84.7 and 13.3% of total bacteria at operational pH 5.3 and pH 7.0, respectively, after 48 h operation.

  15. Sorptive stabilization of organic matter by amorphous Al hydroxide

    NARCIS (Netherlands)

    M.P.W. Schneider; T. Scheel; R. Mikutta; P. van Hees; K. Kaiser; K. Kalbitz

    2010-01-01

    Amorphous Al hydroxides (am-Al(OH)(3)) strongly sorb and by this means likely protect dissolved organic matter (OM) against microbial decay in soils. We carried out batch sorption experiments (pH 4.5; 40 mg organic C L-1) with OM extracted from organic horizons under a Norway spruce and a European b

  16. Effects of Al(III and Nano-Al13 Species on Malate Dehydrogenase Activity

    Directory of Open Access Journals (Sweden)

    Rong Fu Chen

    2011-05-01

    Full Text Available The effects of different aluminum species on malate dehydrogenase (MDH activity were investigated by monitoring amperometric i-t curves for the oxidation of NADH at low overpotential using a functionalized multi-wall nanotube (MWNT modified glass carbon electrode (GCE. The results showed that Al(III and Al13 can activate the enzymatic activity of MDH, and the activation reaches maximum levels as the Al(III and Al13 concentration increase. Our study also found that the effects of Al(III and Al13 on the activity of MDH depended on the pH value and aluminum speciation. Electrochemical and circular dichroism spectra methods were applied to study the effects of nano-sized aluminum compounds on biomolecules.

  17. Avaliação da tolerância de larvas do pacamã Lophiosilurus alexandri Steindachner, 1877 (Pisces:Siluriformes a diferentes salinidades - DOI: 10.4025/actascibiolsci.v30i4.791 Evaluation of the tolerance of “pacamã” Lophiosilurus alexandri Steindachner, 1877 (Pisces:Siluriformes larvae to different salinities - DOI: 10.4025/actascibiolsci.v30i4.791

    Directory of Open Access Journals (Sweden)

    Ronald Kennedy Luz

    2008-11-01

    Full Text Available O objetivo deste trabalho foi avaliar a tolerância de larvas de pacamã Lophiosilurus alexandri ao teste agudo de salinidade da água em diferentes idades. Os testes foram realizados em larvas recém-eclodidas, com oito e 12 dias pós-eclosão. As larvas foram aclimatadas às condições experimentais por 24h, sendo estocadas em 18 tanques plásticos de 1 L na densidade de 15 larvas L-1. Após esse período, as larvas foram transferidas para as salinidades: água doce, 2, 4, 6, 8 e 10 g de sal L-1 e observadas durante 96h. Larvas recém- eclodidas apresentaram mortalidade total em 6, 8 e 10 g de sal L-1 e 100% de sobrevivência para água doce, 2 e 4 g de sal L-1; porém, com redução dos valores de peso e comprimento mediante as duas salinidades. Larvas com oito dias pós-eclosão apresentaram CL(I50-96hde 8,9 g de sal L-1. Para o peso, verificou-se redução gradativa a partir da salinidade de 2 g de sal L-1, mas sem diferenças para o comprimento das larvas entre os tratamentos. Para as larvas com 12 dias pós-eclosão, não se registraram diferenças no comprimento e peso e a sobrevivência foi menor a 8 e 10 g de sal L-1. Larvas com oito e 12 dias pós-eclosão tiveram alterações no comportamento natatório em salinidades superiores a 6 g de sal L-1. Larvas de pacamã apresentaram maior tolerância às diferentes salinidades da água com o desenvolvimento ontogenético.The aim of this study was to analyze the salinity tolerance of “pacamã” Lophiosilurus alexandri larvae at different ages. The test was conducted in post-hatching-larvae and larvae with 8 and 12 days old post-hatching. Larvae were acclimatized to experimental conditions for 24h, kept in 18 plastic tanks with 1 L at a density of 15 larvae L-1. After this period, larvae were subjected to the salinities: freshwater, 2, 4, 6, 8 and 10 g salt L-1, and observed over a period of 96h. Post-hatching larvae exhibited complete mortality in 6, 8 and 10 g salt L-1. Survival was

  18. Hydrothermal Synthesis of Ni/Al Layered Double Hydroxide Nanorods

    OpenAIRE

    Yun Zhao; Fenfei Xiao; Qingze Jiao

    2011-01-01

    Ni/Al layered double hydroxide (LDH) nanorods were successfully synthesized by the hydrothermal reaction. The crystal structure of the products was characterized by X-ray diffraction (XRD). The morphology of the products was observed using transmission electron microscopy (TEM) and field emission scanning electron microscopy (SEM). The influences of reaction time and pH value on the morphology of the Ni/Al LDHs were investigated. The result showed that the well-crystallized nanorods of Ni/Al ...

  19. Efeito de fatores abióticos na larvicultura de pintado amarelo Pimelodus maculatus (Lacépède, 1803: salinidade e cor de tanque - DOI: 10.4025/actascianimsci.v26i2.1859 The effect of abiotic factors on the larviculture of pintado amarelo Pimelodus maculatus (Lacépède 1803: salinity an tank color - DOI: 10.4025/actascianimsci.v26i2.1859

    Directory of Open Access Journals (Sweden)

    Marcos Weingartner

    2004-04-01

    Full Text Available Fatores abióticos podem determinar o sucesso na larvicultura de algumas espécies de peixes. A cor do tanque e salinidade da água de criação podem promover alterações no comportamento e na fisiologia das pós-larvas de peixes. O objetivo deste experimento foi avaliar a influência das salinidades 0,0‰; 0,7‰; 1,4‰; 2,0‰; 2,5‰ e 5,0‰ da água e das cores branca e preta dos tanques na larvicultura de Pimelodus maculatus. A sobrevivência foi afetada pela salinidade (p0,05 entre os tanques branco e preto com valor médio de 31,7±17,7%. Portanto, o valor de 2mg/L de NaCl re velou-se a melhor salinidade para larvicultura de Pimelodus maculatus, e as cores testadas não afetaram a sobrevivência das pós-larvas.Abiotic factors determine the success of the larviculture in some fish species. Tank color and the water salinity can cause alterations in the behavior and physiology of the fish post-larvae. The purpose of this experiment was to evaluate the influence of the difference water salinity concentration (0.0‰; 0.7‰; 1.4‰; 2.0‰; 2.5‰ and 5.0‰ and the use of white or black tanks in the larviculture of Pimelodus maculatus. The survival rate was affected by water salinity (p0.05 between post-larvae stocked in black or white tanks with an average value of 31.7±17.7%. Therefore, 2.0‰ proved to be the best salinity for larviculture of the Pimelodus maculatus, and the colors tested did not affect the survival of the post-larvae.

  20. Ph og børnenes rum

    DEFF Research Database (Denmark)

    de Coninck-Smith, Ning

    2008-01-01

    Arkiteten og kulturkritikeren PH tegnede to bygninger til børn, nemlig fabriksbørnehaven ved Dehns Vaskeri fra 1948 og det ombyggede børnehjem Mindet fra 1954. Bidraget diskuterer PH's særlige greb om arkitektur til børn og placerer det ind i samtidens diskussion om børn, deres udvikling og behov....

  1. Inexpensive and Disposable pH Electrodes

    Science.gov (United States)

    Goldcamp, Michael J.; Conklin, Alfred; Nelson, Kimberly; Marchetti, Jessica; Brashear, Ryan; Epure, Emily

    2010-01-01

    Inexpensive electrodes for the measurement of pH have been constructed using the ionophore tribenzylamine for sensing H[superscript +] concentrations. Both traditional liquid-membrane electrodes and coated-wire electrodes have been constructed and studied, and both exhibit linear, nearly Nernstian responses to changes in pH. Measurements of pH…

  2. Urbanism PhD Research 2008 - 2010

    NARCIS (Netherlands)

    Van der Hoeven, F.D.; Brand, N.; Van der Burg, L.; Çalışkan, O.; Tan, E.R.; Wang, C.-Y.; Zhou, J.

    2009-01-01

    To ensure the quality of the Ph.D. research the Department introduced a special procedure for periodic evaluation: after a period of nine months the potential Ph.D. candidates are asked to present their research design, theoretical framework and methodological approach to the members of the Departme

  3. On Calibration of pH Meters

    Directory of Open Access Journals (Sweden)

    Da-Ming Zhu

    2005-04-01

    Full Text Available The calibration of pH meters including the pH glass electrode, ISE electrodes,buffers, and the general background for calibration are reviewed. Understanding of basicconcepts of pH, pOH, and electrode mechanism is emphasized. New concepts of pH, pOH,as well as critical examination of activity, and activity coefficients are given. Theemergence of new solid state pH electrodes and replacement of the salt bridge with aconducting wire have opened up a new horizon for pH measurements. A pH buffer solutionwith a conducting wire may be used as a stable reference electrode. The misleadingunlimited linear Nernstian slope should be discarded. Calibration curves with 3 nonlinearportions for the entire 0—14 pH range due to the isoelectric point change effect areexplained. The potential measurement with stirring or unstirring and effects by double layer(DL and triple layer (TL will be discussed.

  4. Coaching af ph.d.-studerende

    DEFF Research Database (Denmark)

    Godskesen, Mirjam Irene

    Rapporten danner grundlag for at etablere et koncept for ph.d.-coaching. Erfaringerne fra et 2-årigt projekt om ph.d.-coaching i SCKK regi beskrives. De centrale temaer er tilrettelæggelse af den individuelle coaching, typiske temaer i coachingen og arbejdsdeling mellem coach og vejleder. Der er...

  5. The influence of pH on the corrosion of medium strength aerospace alloy 8090, 2091 and 2014

    DEFF Research Database (Denmark)

    Ambat, Rajan; Dwarakadasa, E.S.

    1992-01-01

    The influence of pH on the corrosion behaviour of two aluminium-lithium-copper-magnesium-zirconium (8090 and 2091) alloys was studied and compared with a standard aircraft alloy, 2014 (Al-4.4% Cu) and 99.9% pure Al. In constant exposure and potentiodynamic polarization studies conducted in 3.5% N...

  6. Ph.d.-indlevering Aalborg Universitet

    DEFF Research Database (Denmark)

    Haladyn, Maria Abildgaard; Greve, Anne Marya

    Universitetets ph.d.-afhandlinger er en væsentlig kilde i eksponeringen af Aalborg Universitets forskningsaktivitet, og en ressource der efterspørges bredt såvel blandt fagfæller som erhvervsliv både i et nationalt og et internationalt perspektiv. Det er således i Aalborg Universitets interesse, at...... sikre optimal eksponering af universitetets ph.d.-afhandlinger gennem publicering i Aalborg Universitets Ph.d.-serier. Forud for publiceringen af den enkelte ph.d.-afhandling ligger en proces, der involverer flere interessenter og organisatoriske enheder på AAU, og det er Aalborg Universitets ønske at...... etablere en strømlinet proces for indlevering, arkivering, trykning og publicering af ph.d.-afhandlinger....

  7. “Maybe PhD students shouldn’t do literature reviews … it’s a job for senior researchers”

    DEFF Research Database (Denmark)

    Bay, Gina

    store mængder) data. (Hart, 1998; Holbrook et al, 2007; Jesson et al., 2011; Nolin, 2012; Papaioannou et al., 2010). Hvad betyder denne udvikling for de krav der meningsfuldt kan stilles til ph.d.-studerendes informationskompetencer? Workshoppen vil kort præsentere erfaringer fra og deltagernes...

  8. Biochar contribution to soil pH buffer capacity

    Science.gov (United States)

    Tonutare, Tonu; Krebstein, Kadri; Utso, Maarius; Rodima, Ako; Kolli, Raimo; Shanskiy, Merrit

    2014-05-01

    Biochar as ecologically clean and stable form of carbon has complex of physical and chemical properties which make it a potentially powerful soil amendment (Mutezo, 2013). Therefore during the last decade the biochar application as soil amendment has been a matter for a great number of investigations. For the ecological viewpoint the trend of decreasing of soil organic matter in European agricultural land is a major problem. Society is faced with the task to find possibilities to stabilize or increase soil organic matter content in soil and quality. The availability of different functional groups (e.g. carboxylic, phenolic, acidic, alcoholic, amine, amide) allows soil organic matter to buffer over a wide range of soil pH values (Krull et al. 2004). Therefore the loss of soil organic matter also reduces cation exchange capacity resulting in lower nutrient retention (Kimetu et al. 2008). Biochar can retain elements in soil directly through the negative charge that develops on its surfaces, and this negative charge can buffer acidity in the soil. There are lack of investigations about the effect of biochar to soil pH buffering properties, The aim of our investigation was to investigate the changes in soil pH buffer capacity in a result of addition of carbonizated material to temperate region soils. In the experiment different kind of softwood biochars, activated carbon and different soil types with various organic matter and pH were used. The study soils were Albeluvisols, Leptosols, Cambisols, Regosols and Histosols . In the experiment the series of the soil: biochar mixtures with the biochar content 0 to 100% were used. The times of equiliberation between solid and liquid phase were from 1 to 168 hours. The suspension of soil: biochar mixtures was titrated with HCl solution. The titration curves were established and pH buffer capacities were calculated for the pH interval from 3.0 to 10.0. The results demonstrate the dependence of pH buffer capacity from soil type

  9. Evaluation of boron isotope ratio as a pH proxy in the deep sea coral Desmophyllum dianthus: Evidence of physiological pH adjustment

    Science.gov (United States)

    Anagnostou, E.; Huang, K.-F.; You, C.-F.; Sikes, E. L.; Sherrell, R. M.

    2012-10-01

    The boron isotope ratio (δ11B) of foraminifers and tropical corals has been proposed to record seawater pH. To test the veracity and practicality of this potential paleo-pH proxy in deep sea corals, samples of skeletal material from twelve archived modern Desmophyllum dianthus (D. dianthus) corals from a depth range of 274-1470 m in the Atlantic, Pacific, and Southern Oceans, ambient pH range 7.57-8.05, were analyzed for δ11B. The δ11B values for these corals, spanning a range from 23.56 to 27.88, are found to be related to seawater borate δ11B by the linear regression: δ11Bcoral=(0.76±0.28) δ11Bborate+(14.67±4.19) (1 standard error (SE)). The D. dianthus δ11B values are greater than those measured in tropical corals, and suggest substantial physiological modification of pH in the calcifying space by a value that is an inverse function of seawater pH. This mechanism partially compensates for the range of ocean pH and aragonite saturation at which this species grows, enhancing aragonite precipitation and suggesting an adaptation mechanism to low pH environments in intermediate and deep waters. Consistent with the findings of Trotter et al. (2011) for tropical surface corals, the data suggest an inverse correlation between the magnitude of a biologically driven pH offset recorded in the coral skeleton, and the seawater pH, described by the equation: ΔpH=pH recorded by coral-seawater pH=-(0.75±0.12) pHw+(6.88±0.93) (1 SE). Error analysis based on 95% confidence interval(CI) and the standard deviation of the regression residuals suggests that the uncertainty of seawater pH reconstructed from δ11Bcoral is ±0.07 to 0.12 pH units. This study demonstrates the applicability of δ11B in D. dianthus to record ambient seawater pH and holds promise for reconstructing oceanic pH distribution and history using fossil corals.

  10. Activated carbon addition affects soil pH and germination of six plant species

    NARCIS (Netherlands)

    Kabouw, P.; Nab, M.R.; Van Dam, N.M.

    2010-01-01

    Activated carbon (AC) is widely used in ecological studies for neutralizing allelopathic compounds. However, it has been suggested that AC has direct effects on plants because it alters substrate parameters such as nutrient availability and pH. These side-effects of AC addition may interfere with al

  11. Activated carbon addition affects substrate pH and germination of six plant species

    NARCIS (Netherlands)

    Kabouw, P.; Nab, M.; Dam, van M.

    2010-01-01

    Activated carbon (AC) is widely used in ecological studies for neutralizing allelopathic compounds. However, it has been suggested that AC has direct effects on plants because it alters substrate parameters such as nutrient availability and pH. These side-effects of AC addition may interfere with al

  12. ATLAS PhD Grant Scheme

    CERN Multimedia

    2016-01-01

    In this #CERNandSociety video, the 3 PhD students, awarded the ATLAS PhD Grant in 2015, talk about their research work within the ATLAS Collaboration and how this experience has shaped their future. Find out more about the ATLAS PhD Grant Scheme: cern.ch/ATLASPhDGrant This programme is just one of the many #CERNandSociety projects at CERN. Find out more and how you can be involved: http://cern.ch/go/pBt7

  13. Interaction in PhD supervision

    DEFF Research Database (Denmark)

    Kobayashi, Sofie; Grout, Brian William Wilson; Rump, Camilla Østerberg

    D student, her principal supervisor and two co-supervisors. The analysis is informed by positioning theory, where a conversation is viewed as a tri-polar structure of speech-act, positioning, and storylines. Positioning is the act of assigning rights and duties to oneself and to others and storylines......This paper contains an analysis of a single supervision session, undertaken with the aim of identifying how learning opportunities might be created for a PhD student. The supervision session concerned methodologies to be employed in a PhD study related to storm water management and included the Ph...

  14. Classification of some Linseed (Linum usitatissimum L. Genotypes for Salinity Tolerance using Germination, Seedling Growth, and Ion Content Clasificación de algunos Genotipos de Linaza (Linum usitatissimum L. para Tolerancia a Salinidad usando Germinación, Crecimiento de Plántulas y Contenido de Iones

    Directory of Open Access Journals (Sweden)

    Mehmet Demir Kaya

    2012-03-01

    Full Text Available Salinity reduces germination, delays emergence, and inhibits seedling growth of linseed (Linum usitatissimum L. while some varieties are less affected by salinity than others. In this study, we aimed to determine the effects of NaCl levels (0, 5, 10, 20 and 30 dS m-1 on germination and seedling growth of 10 linseed genotypes (lines 87, 89, 104, 114, 193, 194, 209, 215, C-90 and cv. San-85 and to classify the genotypes for salinity tolerance using germination and seedling characteristics. Germination percentage, mean germination time, root and shoot length, seedling fresh and dry weight, Na+ content and Na:K ratio of seedlings were investigated. Classification of linseed genotypes for salinity tolerance was done according to (i combination of Principal Component and Cluster Analysis, (ii Na+ content, and (iii Na:K ratio of seedling. The results showed that the highest values were obtained from lines 193, 194 and 215 except for mean germination time, while germination percentage was not adversely influenced by NaCl up to 20 dS m-1. Seedling growth was inhibited at 20 dS m-1 although genotypes exhibited varying responses. Na+ content was enhanced by NaCl, but seedling from lines 194, 193 and 215 had the lowest Na+ content at all NaCl levels. Cluster analysis performed by multiple parameters revealed three groups for salinity tolerance. It was concluded that lines 193, 194, and 215 were tolerant, lines 87, 209, C-90, and cv. Sari-85 were moderately tolerant and lines 89, 104, and 114 were salt-sensitive genotypes. Classification of genotypes for Na+ content and Na:K ratio showed similar result for tolerant genotypes while different genotypes for sensitive group were detected.La salinidad reduce germinación, retrasa emergencia, e inhibe el crecimiento de plántulas de lino (Linum usitatissimum L. mientras algunas variedades son menos afectadas por la salinidad que otras. El objetivo de este estudio fue determinar los efectos de niveles de NaCl (0, 5

  15. Efeitos da salinidade da água de irrigação na brotação e desenvolvimento inicial da cana-de-açúcar (Saccharum spp e em solos com diferentes níveis texturais Effects of irrigation water salinity upon the sprouting and initial development of sugar cane (Saccharum spp and on soils with different textural levels

    Directory of Open Access Journals (Sweden)

    Márcio José de Santana

    2007-10-01

    Full Text Available Foram avaliados os efeitos de diferentes concentrações de sal na água de irrigação, no desenvolvimento inicial da cana-de-açúcar, cultivar SP80-1842, cultivada em solos com diferentes níveis texturais. O experimento foi conduzido em casa-de-vegetação do Departamento de Engenharia da Universidade Federal de Lavras, em Lavras, MG. A finalidade do cultivo em ambiente protegido foi de possibilitar os tratamentos de níveis de sal na água de irrigação, sem a interferência das precipitações pluviométricas. Os tratamentos consistiram em quatro níveis de salinidade da água de irrigação (condutividade elétrica de 0,10; 2,0; 5,0 e 8,0 dS m-1, e três classes texturais de solo (texturas arenosa, média e argilosa, totalizando doze tratamentos e caracterizando um delineamento inteiramente casualizado (DIC, em esquema fatorial de 4 X 3, com oito repetições. No início e após experimentação, foram coletadas amostras dos solos para obtenção da condutividade elétrica do extrato saturado, retratando o efeito da salinidade da água de irrigação sobre os tipos de solo. Aos 38 dias após plantio das gemas, obteve-se a massa seca da raiz e da parte aérea, sendo que, durante a experimentação foram contados, diariamente, o número de gemas que brotavam em cada vaso. Os resultados mostraram que a cana-de-açúcar, cultivar SP80-1842, é sensível a salinidade da água de irrigação, durante sua fase inicial de cultivo. Todos os parâmetros vegetativos foram reduzidos com aumento da salinidade da água de irrigação. Houve um aumento da salinidade do solo em virtude do aumento da condutividade elétrica da água de irrigação. As maiores médias dessas variáveis foram obtidas no solo de textura média.The different concentrations of salt in the irrigation water on the initial development of sugar cane, cultivar SP80-1842, grown in soils with different textural levels were evaluated. The experiment was conducted in a greenhouse of

  16. Brenda K. Edwards, PhD

    Science.gov (United States)

    Brenda K. Edwards, PhD, has been with the Surveillance Research Program (SRP) and its predecessor organizations at the National Cancer Institute (NCI) since 1989, serving as SRP’s Associate Director from 1990-2011.

  17. What PhD students really want

    CERN Document Server

    Mao, Minnie

    2010-01-01

    The road to becoming an astronomer is exciting, but often fraught with danger and conflicting messages. A PhD student is inundated with catch-phrases such as "publish or perish" and "it's not about the quantity, but the quality of work". How do we know which advice to follow? How can we publish copious amounts of quality work in only three years so as to maximize our success in the future? How do we even know what "good quality" really is? With only a short time to prepare ourselves for the big wide world of Astronomy, what is the best way for a PhD student to maximize their research and ultimately maximize their success as a real astronomer? The PhD students of today are the astronomers of tomorrow, but their journey depends on a positive work environment in which they can thrive and improve. Here I present the results of a survey of current PhD students on how they believe they can maximize their success in science. I find that PhD students in Australia expect to write more papers during their PhD than is e...

  18. Contribuição de solutos orgânicos e inorgânicos no ajustamento osmótico de pinhão-manso submetido à salinidade Contribution of organic and inorganic solutes to osmotic adjustment of physic nut under salinity

    Directory of Open Access Journals (Sweden)

    Evandro Nascimento da Silva

    2009-05-01

    Full Text Available O objetivo deste trabalho foi avaliar a acumulação de solutos orgânicos e inorgânicos e suas contribuições para o ajustamento osmótico de folhas de pinhão-manso (Jatropha curcas L. submetido à salinidade. O experimento foi conduzido em delineamento experimental inteiramente casualizado, com cinco tratamentos (0, 25, 50, 75 e 100 mmol L-1 de NaCl e quatro repetições. As plantas foram cultivadas hidroponicamente em casa de vegetação, em condições controladas de fotoperíodo (12 horas, temperatura (média de 28ºC e umidade relativa do ar (média de 65%, com radiação fotossinteticamente ativa máxima média de 700 µmol m-1 s-1. O potencial osmótico das folhas decresceu progressivamente e variou de -0,84 a -2,05 MPa, enquanto o conteúdo relativo de água aumentou nos tratamentos com 75 e 100 mmol L-1. Os íons Na+ e Cl- foram os mais importantes, em termos quantitativos, e contribuíram com cerca de 52 e 20%, respectivamente, para o ajustamento osmótico das folhas de plantas tratadas com NaCl. A contribuição do K+ decresceu de modo acentuado e foi de 17 e 5% nos tratamentos com 25 e 100 mmol L-1 de NaCl. A contribuição média dos solutos orgânicos, açúcares, aminoácidos, glicina betaína e prolina, foi de 5,5, 6, 4 e 0,03%, respectivamente. As folhas de pinhão-manso ajustam-se osmoticamente em presença de salinidade, e mantêm bom nível de hidratação, principalmente por meio da acumulação de Na+ e Cl-. A glicina betaína tem papel quantitativo mais importante do que a prolina no ajustamento osmótico, tanto em presença quanto em ausência de salinidade.The objectives of this work were to evaluate the organic and inorganic solutes accumulation and measure their contribution to the osmotic adjustment of physic nut (Jatropha curcas L. leaves under salinity. The experiment was carried out using a completely randomized design with five treatments (0, 25, 50, 75, and 100 mmol L-1 of NaCl and four replications. Plants

  19. Electrochemical properties of Fe and Al hydroxides as affected by different supporting electrolytes

    OpenAIRE

    Melis, Pietro; Premoli, Alessandra Maria; Solinas, Vincenzo; Deiana, Salvatore Andrea

    1984-01-01

    Potentiometric titration curves of Fe and Al hydroxides, carried out in presence of different electrolytes (KCI, Kbr, KI, KNO3, KCIO4) were elaborated by the Stern theory through a computered program. The zero points of charge (zpc), calculated from the intersection point of the titration curves at different ionic strenght, varied from pH 7.10 to pH 7.65 for Fe hydroxides and from pH 9.10 pH 9.45 for Al hydroxi des. For Fe compounds, a good match was found between the experimen...

  20. Eukaryotic diversity at pH extremes

    Directory of Open Access Journals (Sweden)

    Linda A. Amaral-Zettler

    2013-01-01

    Full Text Available Extremely acidic (pH<3 and extremely alkaline (pH>9 environments support a diversity of single-cell and to a lesser extent, multicellular eukaryotic life. This study compared alpha and beta diversity in eukaryotic communities from 7 diverse aquatic environments with pH values ranging from 2 to 11 using massively-parallel pyrotag sequencing targeting the V9 hypervariable region of the 18S ribosomal RNA (rRNA gene. A total of 946 Operational Taxonomic Units (OTUs were recovered at a 6% cut-off level (94% similarity across the sampled environments. Hierarchical clustering of the samples segregated the communities into acidic and alkaline groups. Similarity Percentage Analysis (SIMPER followed by Indicator OTU Analysis (IOA and Non-metric Multidimensional Scaling (NMDS were used to determine which characteristic groups of eukaryotic taxa typify acidic or alkaline extremes and the extent to which pH explains eukaryotic community structure in these environments. Spain’s Rio Tinto yielded the fewest observed OTUs while Nebraska Sandhills alkaline lakes yielded the most. Distinct OTUs, including metazoan OTUs, numerically dominated pH extreme sites. Indicator OTUs included the diatom Pinnularia and unidentified opisthokonts (Fungi and Filasterea in the extremely acidic environments, and the ciliate Frontonia across the extremely alkaline sites. Inferred from NMDS, pH explained only a modest fraction of the variation across the datasets, indicating that other factors influence the underlying community structure in these environments. The findings from this study suggest that the ability for eukaryotes to adapt to pH extremes over a broad range of values may be rare, but further study of taxa that can broadly adapt across diverse acidic and alkaline environments respectively present good models for understanding adaptation and should be targeted for future investigations.

  1. Amyotrophic Lateral Sclerosis (ALS)

    Science.gov (United States)

    ... benefit of 16 months before onset of severe respiratory failure. Other treatments are designed to relieve symptoms and ... of ALS. Most people with ALS die from respiratory failure, usually within 3 to 5 years from the ...

  2. Utilización de azufre micronizado en la corrección del pH de compost de residuos de poda Correction of the pH of pruning waste compost with micronized sulphur

    Directory of Open Access Journals (Sweden)

    L.A. Barbaro

    2010-12-01

    Full Text Available Los compost actualmente son muy utilizados como componentes de sustratos, aunque en algunos casos presentan pH alcalinos y causan problemas nutricionales. Por ello se recomienda hacer una corrección previa a su utilización o luego de elaborar el sustrato. Algunas alternativas para bajar el pH es mezclando el compost con materiales ácidos o mediante la adición de azufre, sulfato ferroso u otros compuestos azufrados. El objetivo de este trabajo fue corregir el pH de un compost de residuos de poda con azufre micronizado y hallar la dosis adecuada para el pH deseado. Se conformaron siete tratamientos, incorporando al compost de poda diferentes dosis de azufre micronizado: 0, 1, 2, 3, 4, 6 y 8 g/litro. Al compost de cada tratamiento se le midió el pH semanalmente y una vez estabilizados se analizó la conductividad eléctrica, concentración de nitrato, calcio, magnesio, potasio y sodio. Para un pH entre 5,3 y 6,2 se necesitaron 2 a 3 g de azufre/litro. El pH del compost disminuyó con el incremento de la dosis de azufre, y la CE aumentó. El azufre micronizado es una alternativa viable para corregir el pH del compost de restos de poda a los valores deseados.Nowadays, composts are widely used for incorporation into substrates and in some cases they present alkaline pH, causing nutritional problems. Therefore, it is suggested that a correction should be made prior to its use or after its preparation. Some alternatives to decrease pH values are mixing compost with acid materials or adding sulphur, ferrous sulphate or other sulphur compounds. The aim of this work was to correct the pH of pruning waste compost with micronized sulphur and find the appropriate dose for the desired pH. Seven treatments were performed incorporating different doses of micronized sulphur: 0, 1, 2, 3, 4, 6 and 8 g per liter of compost. Compost pH was measured weekly in each treatment. Once stabilized, electrical conductivity and concentration of nitrate, calcium, magnesium

  3. Fiber-Optic pH Sensor

    Science.gov (United States)

    Ganesh, A. Balaji; Radhakrishnan, T. K.

    The new enhancement in the determination of pH using optical fiber system is described here. This work uses the membrane made of cellulose acetate membrane for reagent immobilization and congo red (pKa 3.7) and neutral red (pKa 7.2) as pH indicators. An effective covalent chemical binding procedure is used to immobilize the indicatorsE The response time, reversibility, linear range, reproducibility, and long-term stability of fiber optic sensor with congo red as well as neutral red have been determined. The linear range measured for the sensor based on the congo red and neutral red is 4.2-6.3 and 4.1-9.0, respectively. The response time of sensor membrane is measured by varying the substance pH values between 11.0 and 2.0.

  4. Pattern recognition of ocean pH

    Science.gov (United States)

    Parker, Albert

    2016-09-01

    The manuscript shows how the few, scattered, latest measurements of ocean pH lacking a proper spatial and time coverage do not permit a meaningful computation of global trends, as the ocean pH is strongly variable in latitude, longitude and depth and very likely is subject to the multi-decadal oscillations that have been identified in the atmospheric and ocean systems. The proposed mathematical model is based on the assumption that the monthly averaged ocean pH may be described by the superposition of a linear trend and inter-annual, decadal and multi-decadal oscillations, with linear and sinusoidal regression coefficients requiring data that are presently unavailable.

  5. Interview with Di Gao PhD

    Directory of Open Access Journals (Sweden)

    Di Gao

    2016-04-01

    Full Text Available Di Gao is currently a scientist in the Quality Control department of AstraZeneca. She is responsible for technology transfer, stability programs and supporting regulatory submission. She has a BSc and PhD degree in chemistry and interned with Genentech in 2012. After completing her Ph.D. from University of Michigan in June 2013, she joined the R&D department of the United States Pharmacopeia (USP to support USP monograph modernization and since June 2014 she has been working in her current position at AstraZeneca. Recently, she won a prestigious award from Women in Bio (WIB. WIB is an organization of professionals committed to promoting careers, leadership and entrepreneurship for women in the life sciences. This interview was conducted by Roland J.W. Meesters PhD, Editor-in-Chief of Journal of Applied Bioanalysis.

  6. The final frontier of pH and the undiscovered country beyond.

    Directory of Open Access Journals (Sweden)

    Wojciech Bal

    Full Text Available The comparison of volumes of cells and subcellular structures with the pH values reported for them leads to a conflict with the definition of the pH scale. The pH scale is based on the ionic product of water, K(w = [H(+]×[OH(-].We used K(w [in a reversed way] to calculate the number of undissociated H(2O molecules required by this equilibrium constant to yield at least one of its daughter ions, H(+ or OH(- at a given pH. In this way we obtained a formula that relates pH to the minimal volume V(pH required to provide a physical meaning to K(w, V(pH=10(pH-pK(w/2 x 10(pK(w/2/N(A (where N(A is Avogadro's number. For example, at pH 7 (neutral at 25°C V(pH =16.6 aL. Any deviation from neutral pH results in a larger V(pH value. Our results indicate that many subcellular structures, including coated vesicles and lysosomes, are too small to contain free H(+ ions at equilibrium, thus the definition of pH based on K(w is no longer valid. Larger subcellular structures, such as mitochondria, apparently contain only a few free H(+ ions. These results indicate that pH fails to describe intracellular conditions, and that water appears to be dissociated too weakly to provide free H(+ ions as a general source for biochemical reactions. Consequences of this finding are discussed.

  7. Eukaryotic diversity at pH extremes.

    Science.gov (United States)

    Amaral-Zettler, Linda A

    2012-01-01

    Extremely acidic (pH 9) environments support a diversity of single-cell and to a lesser extent, multicellular eukaryotic life. This study compared alpha and beta diversity in eukaryotic communities from seven diverse aquatic environments with pH values ranging from 2 to 11 using massively-parallel pyrotag sequencing targeting the V9 hypervariable region of the 18S ribosomal RNA (rRNA) gene. A total of 946 operational taxonomic units (OTUs) were recovered at a 6% cut-off level (94% similarity) across the sampled environments. Hierarchical clustering of the samples segregated the communities into acidic and alkaline groups. Similarity percentage (SIMPER) analysis followed by indicator OTU analysis (IOA) and non-metric multidimensional scaling (NMDS) were used to determine which characteristic groups of eukaryotic taxa typify acidic or alkaline extremes and the extent to which pH explains eukaryotic community structure in these environments. Spain's Rio Tinto yielded the fewest observed OTUs while Nebraska Sandhills alkaline lakes yielded the most. Distinct OTUs, including metazoan OTUs, numerically dominated pH extreme sites. Indicator OTUs included the diatom Pinnularia and unidentified opisthokonts (Fungi and Filasterea) in the extremely acidic environments, and the ciliate Frontonia across the extremely alkaline sites. Inferred from NMDS, pH explained only a modest fraction of the variation across the datasets, indicating that other factors influence the underlying community structure in these environments. The findings from this study suggest that the ability for eukaryotes to adapt to pH extremes over a broad range of values may be rare, but further study of taxa that can broadly adapt across diverse acidic and alkaline environments, respectively present good models for understanding adaptation and should be targeted for future investigations.

  8. Interview with Di Gao PhD

    OpenAIRE

    Di Gao

    2016-01-01

    Di Gao is currently a scientist in the Quality Control department of AstraZeneca. She is responsible for technology transfer, stability programs and supporting regulatory submission. She has a BSc and PhD degree in chemistry and interned with Genentech in 2012. After completing her Ph.D. from University of Michigan in June 2013, she joined the R&D department of the United States Pharmacopeia (USP) to support USP monograph modernization and since June 2014 she has been working in her current p...

  9. CONTINUOUS MEASUREMENT OF THE CYTOPLASMIC PH IN LACTOCOCCUS-LACTIS WITH A FLUORESCENT PH INDICATOR

    NARCIS (Netherlands)

    MOLENAAR, D; ABEE, T; KONINGS, WN

    1991-01-01

    The cytoplasmic pH of Lactococcus lactis was studied with the fluorescent pH indicator 2',7'-bis-(2-carboxyethyl)-5 (and-6)-carboxyfluorescein (BCECF). A novel method was applied for loading bacterial cells with BCECF, which consists of briefly treating a dense cell suspension with acid in the prese

  10. Busy period analysis of the level dependent PH/PH/1/K queue

    NARCIS (Netherlands)

    Al Hanbali, Ahmad

    2011-01-01

    In this paper, we study the transient behavior of a level dependent single server queuing system with a waiting room of finite size during the busy period. The focus is on the level dependent PH/PH/1/K queue. We derive in closed form the joint transform of the length of the busy period, the number o

  11. Ruminal pH regulation and nutritional consequences of low pH

    NARCIS (Netherlands)

    Dijkstra, J.; Ellis, J.L.; Kebreab, E.; Strathe, A.B.; Lopez, S.; France, J.; Bannink, A.

    2012-01-01

    Volatile fatty acids (VFA) and lactic acid can build up in the rumen and reduce ruminal pH. Low ruminal pH for prolonged periods each day can affect feed intake, microbial metabolism and feed digestion, and has also been related to inflammation, diarrhea and milk fat depression. This paper considers

  12. pH homeostasis in Leishmania donovani amastigotes and promastigotes.

    OpenAIRE

    Glaser, T A; Baatz, J E; Kreishman, G P; Mukkada, A J

    1988-01-01

    Intracellular pH and pH gradients of Leishmania donovani amastigotes and promastigotes were determined over a broad range of extracellular pH values. Intracellular pH was determined by 31P NMR and by equilibrium distribution studies with 5,5-dimethyloxazolidine-2,4-dione or methylamine. Promastigotes maintain intracellular pH values close to neutral between extracellular pH values of 5.0 and 7.4. Amastigote intracellular pH is maintained close to neutral at external pH values as low as 4.0. B...

  13. The Ph.D. Value Proposition

    Science.gov (United States)

    Cooper, Kenneth J.

    2012-01-01

    Atlanta University launched its doctor of arts in humanities (DAH) programs almost 40 years ago, and, since the 1988 merger with Clark College, Clark Atlanta University has continued to award the degrees. This fall, for the first time, its students will be able to earn Ph.D.s in humanities instead. In DAH programs around the country, there's been…

  14. Optoelectronic pH Meter: Further Details

    Science.gov (United States)

    Jeevarajan, Antony S.; Anderson, Mejody M.; Macatangay, Ariel V.

    2009-01-01

    A collection of documents provides further detailed information about an optoelectronic instrument that measures the pH of an aqueous cell-culture medium to within 0.1 unit in the range from 6.5 to 7.5. The instrument at an earlier stage of development was reported in Optoelectronic Instrument Monitors pH in a Culture Medium (MSC-23107), NASA Tech Briefs, Vol. 28, No. 9 (September 2004), page 4a. To recapitulate: The instrument includes a quartz cuvette through which the medium flows as it is circulated through a bioreactor. The medium contains some phenol red, which is an organic pH-indicator dye. The cuvette sits between a light source and a photodetector. [The light source in the earlier version comprised red (625 nm) and green (558 nm) light-emitting diodes (LEDs); the light source in the present version comprises a single green- (560 nm)-or-red (623 nm) LED.] The red and green are repeatedly flashed in alternation. The responses of the photodiode to the green and red are processed electronically to obtain the ratio between the amounts of green and red light transmitted through the medium. The optical absorbance of the phenol red in the green light varies as a known function of pH. Hence, the pH of the medium can be calculated from the aforesaid ratio.

  15. pH testing - The basics

    NARCIS (Netherlands)

    Smout, Andre J. P. M.

    2008-01-01

    Esophageal pH testing, first described more than 3 decades ago, has become incorporated in the diagnostic armamentarium of most gastroenterologists. Using commercially available sophisticated equipment and software, the procedure is easy to perform and the analysis of the signals is automated. Never

  16. What My Ph.D. Taught Me

    Science.gov (United States)

    Levenstein, Jessica

    2013-01-01

    The author started in the Ph.D. program in comparative literature at Princeton in 1992, a year after she graduated from college. She fell in love with mythology and the classical traditions and find herself teaching literature. In the remainder of her time at Princeton, she precepted for four or five more classes, got the chance to join the…

  17. Blending Canal Surfaces Based on PH Curves

    Institute of Scientific and Technical Information of China (English)

    Chen-Dong Xu; Fa-Lai Chen

    2005-01-01

    In this paper, a new method for blending two canal surfaces is proposed. The blending surface is itself a generalized canal surface, the spine curve of which is a PH (Pythagorean-Hodograph) curve. The blending surface possesses an attractive property - its representation is rational. The method is extensible to blend general surfaces as long as the blending boundaries are well-defined.

  18. OpenPh - Numerical Physics Library

    CERN Document Server

    Milescu, George; Pop, Florin

    2011-01-01

    Numerical physics has gained a lot of importance in the last decade, its efficiency being motivated and sustained by the growth of computational power. This paper presents a concept that is to be developed in the next few years: OpenPh. OpenPh is a numerical physics library that makes use of the advantages of both open source software and MATLAB programming. Its aim is to deliver the instruments for providing numerical and graphical solutions for various physics problems. It has a modular structure, allowing the user to add new modules to the existing ones and to create its own modules according to its needs, being virtually unlimited extendable. The modules of OpenPh are implemented using MATLAB engine because it is the best solution used in engineering and science, providing a wide range of optimized methods to accomplish even the toughest jobs. Current version of OpenPh includes two modules, the first one providing tools for quantum physics and the second one for mechanics. The quantum physics module deals...

  19. Das sogenannte "Kinderdefizit" als Phänomen der Archäologie des Mittelalters

    DEFF Research Database (Denmark)

    Atzbach, Rainer

    2009-01-01

    In German archaeology the problem of statistical lack of children in medieval graveyards have been discussed intensively. Although it seems to be a consequence of misinterpretation of archaeological data there is an unexplained increasing share of children between the 10th and the 16th century ac...... according to shoes....

  20. Volver al desarrollo

    Directory of Open Access Journals (Sweden)

    Jaime Ornelas Delgado

    2012-01-01

    Full Text Available El desarrollo, categoría empleada para expresar el crecimiento económico, surge durante la "guerra fría" y si bien fue propuesta por teóricos metropolitanos, se asumió en Latinoamérica como parte de los instrumentos disponibles para lograr el crecimiento y alternativa al socialismo. El desarrollo mantuvo su vigencia entre 1945 y 1975, cuando al advenimiento del neoliberalismo fue paulatinamente retirado de la agenda de las preocupaciones nacionales e internacionales. Al iniciarse el siglo xxi, el fracaso del mercado autorregulado trajo de nueva cuenta al debate los problemas del desarrollo, lo que obliga a revisarlo críticamente, tanto como al concepto mismo para mostrar su carácter colonial, si se quiere construir caminos ajenos al neoliberal y superar los problemas que han hecho de Latinoamérica una de las regiones más desiguales del mundo.

  1. Al2O3-Coated Nano-SiC Particles Reinforced Al2O3 Matrix Composites

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Properties of Al2O3-coated nano-SiC have been compared with those of as-received SiC. The isoelectric point (IEP)of SiC changed from pH3.4 to pH7.3 after coating with the alumina precursor, which is close to that of alumina.Because both surfaces of coated SiC and Al2O3 possess higher positive charge at pH=4.5~5.0, they are uniformly dispersed in the two-phase aqueous suspensions, Then a mixed powder containing nano-SiC dispersed homogeneously into the Al2O3 matrix was achieved from flocculating the two-phase suspension. Finally, Al2O3/SiC nanocomposites were obtained by coating nano-SiC with Al2O3, in which the majority of SiC particles were located within the Al2O3 grains. The observation by transmission electron microscopy (TEM) and the analysis by the X-ray photoelectron spectroscopy (XPS) showed that cracks propagated towards the intragranular SiC rather than along grain boundaries.

  2. PhMI-St-AN耐热改性剂的合成及与PVC的共混发泡%Synthesis of PhMI-St-AN Heat-Resistant Modifier and Blending Foaming with PVC

    Institute of Scientific and Technical Information of China (English)

    马莉娜; 齐暑华; 程博; 何栋; 邱华; 尚磊

    2012-01-01

    采用悬浮共聚合法制备N-苯基马来酰亚胺-苯乙烯-丙烯腈( PhMI-St-AN)三元共聚物耐热改性剂,将其与聚氯乙烯(PVC)共混通过模压发泡制备了PVC/PhMI-St-AN泡沫塑料.借助傅里叶变换红外光谱、差示扫描量热分析等手段对PhMI-St-AN三元共聚物进行了表征,研究了共聚物组成对三元共聚物玻璃化转变温度(Tg)及其与PVC相容性的影响,考察了PVC/PhMI-St-AN泡沫塑料的热尺寸稳定性和吸水性.结果表明,PhMI-St-AN具有良好的耐热性能,其Tg随PhMI含量的增加而提高,PhMI-St-AN三元共聚物提高了PVC/PhMI-St-AN泡沫塑料的热尺寸稳定性,降低了吸水率.%N-phenyl maleimide-styrene-acrylonitrile ( PhMI-St-AN ) terpolymer was prepared through suspension copolymerization method, and the terpolymer as heat-resistant modifiers was blended with PVC to prepare PVC/PhMI-St-AN foam plastics by moulding and foaming. Then PhMI-St-AN terpolymer was characterized by the means of FTIR, DSC et al. Effects of the terpolymer composition on the glass transition temperature ( Tg) of PhMI-St-AN terpolymer and the compatibility between PhMI-St-AN terpolymer and PVC were studied. Meanwhile, the thermal dimensional stability and water absorption property of PVC / PhMI-St-AN foam plastics were researched. The results showed that PhMI-St-AN terpolymer had good heat resistance, and it' s Tg improved with the increase of PhMI content in the terpolymer. By adding PhMI-St-AN terpolymer, the thermal dimensional stability of PVC foam plastics was improved and the water absorption rate of foam plastics was reduced.

  3. Jalta als Heterotopie

    OpenAIRE

    Schmid, Ulrich

    2013-01-01

    Jalta ist ein Ort, der sich im europäischen Kulturgedächtnis sowohl historisch als auch literarisch als "radikal anderer Ort" - als " Heterotopie" - festgesetzt hat. An der Konferenz von Jalta wurde 1945 eine neue Weltordnung geschaffen in der Hoffnung auf eine bessere Welt. Auch in den Werken von Anton ?echov, vor allem in denjenigen, die in Jalta entstanden sind, wird von einer anderen und besseren Welt geträumt.

  4. Pornographie als Metapher

    OpenAIRE

    Caroline Schubarth

    2010-01-01

    In diesem Artikel werden unterschiedliche metaphorische Verwendungen des Pornografiebegriffs und deren Implikationen untersucht. Während die Existenz von Pornografie der feministischen Anti-Porno-Bewegung als Erklärung für die anhaltende Diskriminierung von Frauen in westlichen Gesellschaften dient, nutzen rechtskonservative Kräfte den Pornografievorwurf als Rechtfertigung für die Zensur von als deviant empfundenen Identitäten und sexuellen Praktiken.This article...

  5. Pornographie als Metapher

    Directory of Open Access Journals (Sweden)

    Caroline Schubarth

    2010-02-01

    Full Text Available In diesem Artikel werden unterschiedliche metaphorische Verwendungen des Pornografiebegriffs und deren Implikationen untersucht. Während die Existenz von Pornografie der feministischen Anti-Porno-Bewegung als Erklärung für die anhaltende Diskriminierung von Frauen in westlichen Gesellschaften dient, nutzen rechtskonservative Kräfte den Pornografievorwurf als Rechtfertigung für die Zensur von als deviant empfundenen Identitäten und sexuellen Praktiken.

  6. Anonymität und Geschlecht in der Phänomenologie Merleau-Pontys

    OpenAIRE

    Kerstin Andermann

    2014-01-01

    In diesem Beitrag wird die Bedeutung von Anonymität für die allgemeine Wahrnehmung und die Wahrnehmung von Geschlechtlichkeit untersucht. Im Ausgang der Phänomenologie Merleau-Pontys und mit Blick auf den Begriff der Singularität bei Deleuze wird Anonymität als latenter Untergrund der Existenz ausgemacht. Erst durch die Sinnesorgane wird die anonyme Existenz des Körpers überschritten, und so erscheint Anonymität jenseits der Organisation des Körpers als eines Funktionszusammenhangs strukturie...

  7. Role of metal oxide nanostructures in extracellular pH regulations

    Science.gov (United States)

    Lozhkomoev, Aleksandr S.

    2016-08-01

    A research area of great promise is the cancer treatment by regulating microenvironmental parameters of tumor cells using MgO and AlOOH. Magnesium hydroxide and aluminum oxyhydroxide (boehmite) are in the form of nanoplates and nanosheets. The morphology, structure, phases and electrokinetic properties of synthesized samples are analyzed using complex physical and chemical methods. We study how the pH of the culture medium—different when in contact with synthesized nanoplates—affects the viability of tumor cells. It is shown that MgO is more efficient in decreasing the tumor cell viability than AlOOH. In the case of magnesium hydroxide, the pH of the culture medium increases to 10.1; in the case of boehmite, to 7.7.

  8. Adsorptie van Al-ionen aan het kleimineraal montmorilloniet

    NARCIS (Netherlands)

    Bruggenwert, M.G.M.

    1972-01-01

    The adsorption of aluminium ions onto sodium and calcium montmorillonite was studied. Under the experimental conditions (pH 3.5 and 5 and different total salt concentrations) the adsorbed aluminium ions were found to be in the form Al 3+, except when adsorbed onto c

  9. De pH van waschvloeistoffen bij verschillende temperaturen

    NARCIS (Netherlands)

    Smit, R.; Hannewijk, J.

    1943-01-01

    De pH is een begrip, dat de laatste jaren in wasscherijkringen veel opgang heeft gemaakt; men spreekt van de pH van soda, metasilicaat enz. en in de literatuur wordt dikwijls aangegeven, dat men het beste kan wasschen bij pH 10,7, terwijl anderen alleen verklaren, dat de pH boven of beneden een bepa

  10. 21 CFR 876.1400 - Stomach pH electrode.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Stomach pH electrode. 876.1400 Section 876.1400...) MEDICAL DEVICES GASTROENTEROLOGY-UROLOGY DEVICES Diagnostic Devices § 876.1400 Stomach pH electrode. (a) Identification. A stomach pH electrode is a device used to measure intragastric and intraesophageal pH...

  11. ATLAS PhD Grant Scholarship Programme

    CERN Multimedia

    Abha Eli Phoboo

    2014-01-01

    On 11 February, the first recipients of the ATLAS PhD Grant were presented with a certificate by the programme’s selection committee. The three scholars - Lailin Xu of China, Josefina Alconada of Argentina and Gagik Vardanyan of Armenia - were delighted at being able to continue their PhD programmes at CERN.   With certificates, from left: Lailin Xu, Josefina Alconada, and Gagik Vardanyan. The selection committee members, from left: IFAE Barcelona’s Martine Bosman, Fabiola Gianotti, Peter Jenni and from CERN HR James Purvis. (Image: ATLAS/Claudia Marcelloni). Former ATLAS spokespersons Peter Jenni and Fabiola Gianotti started the fund with the Fundamental Physics Prize award money they received last year. Both have used the entirety of their prizes for educational and humanitarian programmes. "We wanted to do something for students who are working on ATLAS, in particular those who otherwise could not come here and actually see the detector they are working on,&am...

  12. PhD students share their work

    CERN Multimedia

    Joannah Caborn Wengler

    2012-01-01

    Last week, the second Doctoral Student Assembly gave students in the final stages of their PhD at CERN the chance to meet and present their work.   On 9 May, 24 students who are completing their PhD under the CERN Doctoral Student Programme were joined by their CERN supervisors and some of their university supervisors at an event organised by HR and the Technical Students Committee (TSC). After an address by the Director-General Rolf Heuer and short presentations by Ingrid Haug from HR and TSC Chair Stephan Russenschuck, the students presented their work in a poster session. Held in a packed Council Chamber, the event was a great opportunity for the doctoral students to get to know each other and to share their work in fields as diverse as radiation protection, computing, physics and engineering.

  13. Phänotypische und funktionelle Charakterisierung von Alveolarmakrophagen der Ratte

    OpenAIRE

    Mertens, Christina

    2012-01-01

    Makrophagen spielen als Zellen der angeborenen Abwehr eine wichtige Rolle bei der Immunabwehr. Ziel dieser Arbeit war die phänotypische und funktionelle Charakterisierung von Alveolarmakrophagen der Ratte. Hierzu wurden die durch eine bronchoalveoläre Lavage gewonnenen Alveolarmakrophagen immunhistologisch und durchflusszytometrisch untersucht. Zusätzlich wurden sie in vitro mit LPS und IFN-g stimuliert. Die Produktion von Stickstoffmonoxid wurde mit dem Griess Reagenz bestimmt und die Expres...

  14. The pH of Enceladus' ocean

    CERN Document Server

    Glein, Christopher; Waite, Hunter

    2015-01-01

    Observational data from the Cassini spacecraft are used to obtain a chemical model of ocean water on Enceladus. The model indicates that Enceladus' ocean is a Na-Cl-CO3 solution with an alkaline pH of ~11-12. The dominance of aqueous NaCl is a feature that Enceladus' ocean shares with terrestrial seawater, but the ubiquity of dissolved Na2CO3 suggests that soda lakes are more analogous to the Enceladus ocean. The high pH implies that the hydroxide ion should be relatively abundant, while divalent metals should be present at low concentrations owing to buffering by clays and carbonates on the ocean floor. The high pH is interpreted to be a key consequence of serpentinization of chondritic rock, as predicted by prior geochemical reaction path models; although degassing of CO2 from the ocean may also play a role depending on the efficiency of mixing processes in the ocean. Serpentinization leads to the generation of H2, a geochemical fuel that can support both abiotic and biological synthesis of organic molecule...

  15. Gezondheid als marketinginstrument

    NARCIS (Netherlands)

    Vijver, van de L.P.L.; Berg, van den I.

    2008-01-01

    Is biologisch voedsel beter dan gangbaar? Hoe hard zijn de bewijzen daarvoor? En hoe sterk moet het bewijs zijn voordat je het als claim op een product mag zetten? In dit Biokennis bericht een overzicht van de wetenschappelijke conclusies en de mogelijkheden om biologisch te promoten als beter, neer

  16. Al-Anon/Alateen

    Science.gov (United States)

    Find an Al-Anon meeting Español | Français 2018 Int'l Convention Home About Group Meetings What If I'm not ready ... a meeting? What can I expect at an Al-Anon meeting? What was my first meeting like? ...

  17. Complexation Key to a pH Locked Redox Reaction

    Science.gov (United States)

    Rizvi, Masood Ahmad; Dangat, Yuvraj; Shams, Tahir; Khan, Khaliquz Zaman

    2016-01-01

    An unfavorable pH can block a feasible electron transfer for a pH dependent redox reaction. In this experiment, a series of potentiometric titrations demonstrate the sequential loss in feasibility of iron(II) dichromate redox reaction over a pH range of 0-4. The pH at which this reaction failed to occur was termed as a pH locked reaction. The…

  18. Al - BASED CAST COMPOSITES

    Directory of Open Access Journals (Sweden)

    Rakesh Kumar Yadav

    2011-08-01

    Full Text Available The economy is very important feature nowadays in themarket. The researches are playing an important role inengineering field to increase the life of machine parts /components and decrease the cost. The compositematerials have the potential to replace widely used steeland aluminium due to their good characteristics withbetter performance. The Al-based composites have foundextensive applications in automobile industries andaerospace industries due to their increased stiffness,strength, thermal conductivity and wear resistanceproperties. A number of particulate phases have beenemployed in the Al-alloy matrix. The cast aluminiumceramicparticulate composites are finding applications inpistons, connecting rods, cylinder liner, engine cylinderblock, electrical contacts etc.The present investigation isbased on study of the effect of particulate phase on theSEM study, micro-hardness, elastic modulus, tensilestrength and the wear behaviour of Al-5 % SiC-7 % Fe,Al-10 % SiC-6 % Fe and Al-15 % SiC-5 % Fe composites.

  19. The Added Value of a PhD in Medicine--PhD Students' Perceptions of Acquired Competences

    Science.gov (United States)

    Anttila, Henrika; Lindblom-Ylänne, Sari; Lonka, Kristi; Pyhältö, Kirsi

    2015-01-01

    PhD in the field of medicine is more common than in any other domain. Many medical doctors are driven towards PhD, but also students with other backgrounds (usually MSc) are conducting a PhD in medical schools. Higher education has invested a lot in developing generic and research competences. Still little is known about how PhD students…

  20. Anonymität und Geschlecht in der Phänomenologie Merleau-Pontys

    Directory of Open Access Journals (Sweden)

    Kerstin Andermann

    2014-04-01

    Full Text Available In diesem Beitrag wird die Bedeutung von Anonymität für die allgemeine Wahrnehmung und die Wahrnehmung von Geschlechtlichkeit untersucht. Im Ausgang der Phänomenologie Merleau-Pontys und mit Blick auf den Begriff der Singularität bei Deleuze wird Anonymität als latenter Untergrund der Existenz ausgemacht. Erst durch die Sinnesorgane wird die anonyme Existenz des Körpers überschritten, und so erscheint Anonymität jenseits der Organisation des Körpers als eines Funktionszusammenhangs strukturierter, signifizierter und unterschiedlich privilegierter Schichten. Ausgehend von Anonymität wird das personale Leben als eine Übernahme von Situationen und als Wechsel zwischen anonym-singulärem und personal-individuellem Leben des Menschen sichtbar. Auch Geschlechtlichkeit wird so als Eintritt in geschlechtlich geprägte Situationen und als eine vieldeutige Spannung zwischen anonymer Existenz und Sein in Situationen deutlich. In diesem Sinne erweist sie sich als eine Übernahme von Situationen aus der Anonymität heraus und ihrer Ausgestaltung sind entsprechende Freiheitsgrade zuzuschreiben.

  1. Effects of pH adjustment with phosphates on attributes and functionalities of normal and high pH beef.

    Science.gov (United States)

    Young, O A; Zhang, S X; Farouk, M M; Podmore, C

    2005-05-01

    Longissimus dorsi muscles from six normal- and six high-ultimate pH bulls were selected for fine mincing and subsequent pH adjustment with acid and alkaline pyrophosphate. Four pH treatments were prepared: initially high remains high (mean of pH 6.37), high becomes normal (5.62); initially normal remains normal (5.65), and normal becomes high (6.21). The addition level of phosphate as P(2)O(5) was the same in all replicates. Before pH adjustment, colour and water holding capacity (WHC) values were strongly affected by higher (initial) pH in expected ways: darker, lower chroma, higher capacity. After pH adjustment, these values were affected only by the final pH, not the initial pH (the pH history). Total protein solubility was likewise affected by final pH but not initial pH. In contrast, the combination high initial pH-high final pH improved sarcoplasmic protein solubility by 20% over the combination normal initial pH-high final pH. Sarcoplasmic protein solubility is an indicator of strain required to fracture cooked batters made from the minced meats; in the event, the rank order of the four treatments for strain-to-fracture matched that of sarcoplasmic protein solubility. Statistically, sarcoplasmic protein solubility and strain-to-fracture were both affected by initial pH (P<0.01) and final pH (P<0.001). However, stress required to fracture cooked batters was entirely controlled by initial pH (P<0.01). In other words, the stress-to-fracture advantage of initially high pH meat was not matched by upward pH adjustment of initially normal pH meat. Emulsion stability, which is better with higher pH meat, was affected by initial and final pH (both P<0.01). Cook yield, like WHC of pH-adjusted raw meat, was more due to final pH than initial pH, similarly cooked batter colour, whereas final pH had a significant effect on quality attributes (generally better when higher). An initially high pH history conferred an enduring advantage on three important batter attributes

  2. Environmental corrosion resistance of porous TiAl intermetallic compounds

    Institute of Scientific and Technical Information of China (English)

    ZHENG Zhi; JIANG Yao; DONG Hong-xing; TANG Lie-min; HE Yue-hui; HUANG Bai-yun

    2009-01-01

    Porous TiAl intermetallic compound, as a novel substitute for current inorganic porous material, offsets the shortages of both ceramics and metals. The environmental corrosion resistance of porous TiAl intermetallic compound was investigated. The kinetic equation for the cyclic oxidation of porous TiAl alloy at 600 ℃ is determined to be Δm2=1.08×10-5t. After total oxidation of 140 h, porous TiAl intermetallic compound shows more stability of pore structure and the mass gain of TiAl alloy is 0.042 g/m2, which is only 10.6% that of porous 316L stainless steel. The kinetic equation for the cyclic corrosion behavior of porous TiAl alloy in hydrochloric acid with pH=2 at 90 ℃ is determined to be Δm2=5.41×10-5t-2.08×10-4. After 50 h exposure, the mass loss of TiAl alloy is 0.049 g/m2, which is only 14.8% and 5.57% that of porous Ti and stainless steel, respectively. The kinetic equation in hydrochloric acid with pH=3 is determined to be Δm2=2.63×10-6t-3.72×10-6.

  3. Effects of pH and Temperature on Calcification of the Planktic Foraminifer O. universa: Insights from Culture Experiments.

    Science.gov (United States)

    Allen, K. A.; Hoenisch, B.; James, K. M.; Eggins, S. M.; Spero, H. J.

    2008-12-01

    The effect of future ocean acidification on marine calcifying organisms is uncertain. Because these calcifiers are intimately tied to ocean chemistry, nutrient cycles, and carbon export to the ocean floor, their sensitivity to pH could impact marine environments and global climate. Here, we present the results of culture experiments that explore the impacts of pH and temperature on the shell morphology and microstructure of the planktic foraminifer Orbulina universa between 18-26°C and pH 7.7-8.8. The largest and heaviest shells are formed at pH 8.4 and 22°C. Average shell diameter and wall thickness decrease ~17% and ~ 35% between pH 8.4 and 7.7. Extrapolation of these data to predicted surface ocean pH over the next century (~ pH 7.9) would imply a decrease in O. universa diameter and thickness of ~ 5% and 12%, respectively, during this period. Two classes of shell pores are observed in O. universa, which are distinctly different in diameter. Large pores are used for cytoplasm flow, food transport and symbiont-streaming in and out of the shell, whereas small pores are likely used for gas and ion exchange. Analysis of pore diameter and pore density (number of pores per 100 μm2 area) show that the large pore parameters do not change with either pH or temperature. In contrast, small pores show a significant increase in pore diameter and decrease in pore density across a pH range of 7.7-8.8. No relationship is found between temperature and porosity, which contradicts early suggestions that porosity can be used as a temperature proxy (Be et al, 1973). The observed negative correlation between pore density in and pH O. universa suggests that this property could serve as a qualitative pH proxy.

  4. pH modeling for maximum dissolved organic matter removal by enhanced coagulation

    Institute of Scientific and Technical Information of China (English)

    Jiankun Xie; Dongsheng Wang; John van Leeuwen; Yanmei Zhao; Linan Xing; Christopher W. K. Chow

    2012-01-01

    Correlations between raw water characteristics and pH after enhanced coagulation to maximize dissolved organic matter (DOM)removal using four typical coagulants (FeCl3,Al2(SO4)3,polyaluminum chloride (PAC1) and high performance polyaluminum chloride (HPAC)) without pH control were investigated.These correlations were analyzed on the basis of the raw water quality and the chemical and physical fractionations of DOM of thirteen Chinese source waters over three seasons.It was found that the final pH after enhanced coagulation for each of the four coagulants was influenced by the content of removable DOM (i.e.hydrophobic,and higher apparent molecular weight (AMW) DOM),the alkalinity and the initial pH of raw water.A set of feed-forward semi-empirical models relating the final pH after enhanced coagulation for each of the four coagulants with the raw water characteristics were developed and optimized based on correlation analysis.The established models were preliminarily validated for prediction purposes,and it was found that the deviation between the predicted data and actual data was low.This result demonstrated the potential for the application of these models in practical operation of drinking water treatment plants.

  5. Biometric characteristics and seedlings nutrition of Pinus taeda under salinity stress at Humic Distrocryept Efeito da salinidade em características biométricas e na nutrição de Pinus taeda em Neossolo Litótico húmico

    Directory of Open Access Journals (Sweden)

    Shizuo Maeda

    2010-06-01

    Full Text Available

    The application of cellulosic waste in forest plantations is an alternative to disposal, but more studies are necessary to confirm the safity of this disposal. The response of Pinus taeda L. to salinity in Humic Distrocryept was evaluated. In plantation, the seedlings were assessed for their height and stem diameter (SD, and at 120 days, were assessed the SD, height, dried root biomass (DRB, shoot (DBS and total dried matter (TDM. The contents of P, K, Ca, Mg and Na were determinated, and, based on these levels it was estimated the quantity of these elements and calculated the efficiency use in leaves and roots and translocation to the shoot. Except the relationship between DSB/DRB, the other variables were significantly influenced by increased salinity with different effects among them. While the SD and its increase and DSP were reduced only in treatment at the more high electric conductivity (EC, the height of the seedlings and the increment tended to reduce from EC of 3.28 dS m-1 and DRB and TDM from the EC 0.55 dS m-1. The efficiency of P and Mg utilization decreased while K and Ca did not alter. The translocation of nutrients was not altered.

     

    doi: 10.4336/2010.pfb.30.61.51

     

     

    A aplicação de resíduos celulósicos em plantios florestais resolve o problema de descarte, porém são necessários estudos que comprovem a segurança dessa forma de disposição. Avaliou-se a resposta de Pinus taeda L. à salinidade, em NEOSSOLO LITÓLICO Húmico. No plantio, avaliaram-se a altura e diâmetro do caule (DC das mudas e, aos 120 dias de cultivo, avaliaram-se a altura, o DC, a biomassa seca das raízes (MSR, parte aérea (MSPA e total (MST. Baseados nos teores de P, K, Ca, Mg e Na, estimaram-se as suas quantidades acumuladas e suas eficiências de utilização nas acículas e raízes e a translocação para a parte aérea. Exceto a razão da relação MSPA/MSR, as demais variáveis foram influenciadas pelo

  6. The leaching of major and trace elements from MSWI bottom ash as a function of pH and time

    NARCIS (Netherlands)

    Dijkstra, J.J.; Sloot, van der H.A.; Comans, R.N.J.

    2006-01-01

    In this paper, the leaching behaviour of major components (Al, Ca, SO4, Mg, Si, Fe, Na and DOC) and trace elements (Ni, Zn, Cd, Cu, Pb, Mo and Sb) from MSWI bottom ash is studied as a function of time over a wide range of pH, under pH-controlled conditions. Equilibrium geochemical modelling using th

  7. Composición Isotópica del Agua Subterránea y su Relación con la Salinidad en el Valle de San Luis Río Colorado en Sonora, México Isotopic composition of groundwater and its relationship with salinity in the Valley of San Luis Rio Colorado Sonora Mexico

    Directory of Open Access Journals (Sweden)

    Lorenzo Valenzuela

    2013-01-01

    Full Text Available En este trabajo, se analiza la composición isotópica del acuífero del Valle de San Luis Río Colorado en Sonora en conjunto con la concentración de cloruros del agua para determinar el origen del agua del subsuelo y establecer las causas del aumento de salinidad que se ha observado en el agua de riego. La mineralización del acuífero ha provocado un deterioro en la calidad del agua de esta agua. Se encontró que la composición isotópica deja ver un fraccionamiento como consecuencia de la evaporación rápida y la mezcla de aguas antiguas, infiltradas antes de la construcción del sistema de presas, con aguas recientes del Río Colorado, sometidas a un proceso de evaporación en los vasos de éstas. El análisis isotópico permitió establecer que el agua de los canales de riego más mineralizada aún no está presente en el acuífero.In this work, the isotopic composition and chloride concentration of San Luis Rio Colorado, Sonora, in Mexico were used to determine the origin of groundwater and to establish the salinity increase that has been observed in the irrigation water. The aquifer mineralization has provoked deterioration of this water. The isotopic composition showed a fractioning due to the sudden evaporation and the mixing of water percolated before the dam system, constructed upstream, with water infiltrated to the aquifer after evaporation in the reservoirs, these water types are known as old and recent, respectively. Unlike what it could be expected, the isotopic composition determined that mineralized water from irrigation channels is not yet present in the aquifer.

  8. Anion exchange removal of Al3+ from Li+-Al3+ aqueous solution (originating from lithium recovery from brine

    Directory of Open Access Journals (Sweden)

    Anissa Somrani

    2014-06-01

    Full Text Available The purpose of this study is to separate aluminum(III ion from an aqueous solution containing Li+ at 25°C. Al3+ was transferred into [Al(C2O43]3- by means of complexation and removed by an anion exchange resin. This resin was anionic type Amberlite IRA 402 regenerated by sodium chloride. Hence, a theoretical study based on speciation diagrams was carried out to determine the best pH domain for separation. The complexation of aluminum ions by ammonium oxalate was studied. The motar ratio of Ox/Al and pH was investigated. Optimum values of these factors were found to be 3 and 4 respectively. In this case, the remaining lithium is 98.5%.

  9. Pursuit of the Ph.D.

    Directory of Open Access Journals (Sweden)

    Scott P. Kerlin

    1995-11-01

    Full Text Available he thesis is put forward that changes in public policy which originally promoted broad access to higher education are leading to the diminished likelihood that minorities, those from low-income backgrounds and females in underrepresented disciplines will pursue, or be able to complete, the doctorate. By reviewing a wide range of research literature and statistical reports on the status of doctoral education in the U.S. & Canada, a detailed sociological portrait of those who pursue the Ph.D. is presented. Recommendations are given for further research on doctoral education, particularly in areas of attrition,retention, student indebtedness, social stratification, and post-doctoral career plans.

  10. ATLAS PhD Grants 2015

    CERN Multimedia

    Marcelloni De Oliveira, Claudia

    2015-01-01

    ATLAS PHd Grants - We are excited to announce the creation of a dedicated grant scheme (thanks to a donation from Fabiola Gianotti and Peter Jenni following their award from the Fundamental Physics Prize foundation) to encourage young and high-caliber doctoral students in particle physics research (including computing for physics) and permit them to obtain world class exposure, supervision and training within the ATLAS collaboration. This special PhD Grant is aimed at graduate students preparing a doctoral thesis in particle physics (incl. computing for physics) to spend one year at CERN followed by one year support also at the home Institute.

  11. Laser-induced breakdown spectroscopy: Extending its application to soil pH measurements

    International Nuclear Information System (INIS)

    Acid–base equilibria are involved in almost all the processes that occur in soil. The bioavailability of nutrients for plants, for instance, depends on the solubilization of mineral nutrients in the soil solution, which is a pH-dependent process. The determination of pH in soil solutions is usually carried out by potentiometry using a glass membrane electrode, after extracting some of the soil components with water or CaCl2 solution. The present work describes a simple method for determining the pH of soil, using laser-induced breakdown spectroscopy (LIBS). Sixty samples presenting different textural composition and pH (previously determined by potentiometry) were employed. The samples were divided into a calibration set with fifty samples and a validation set with ten samples. LIBS spectra were recorded for each pelleted sample using laser pulse energy of 115 mJ. The intensities of thirty-two emission lines for Al, Ca, H, and O were used to fit a partial least squares (PLS) model. The model was validated by prediction of the pH of the validation set samples, which showed good agreement with the reference values. The prediction mean absolute error was 0.3 pH units and the root mean square error of the prediction was 0.4. These results highlight the potential of LIBS for use in other applications beyond elemental composition determinations. For soil analysis, the proposed method offers the possibility of determining pH, in addition to nutrients and contaminants, using a single LIBS measurement. - Highlights: • Physical, chemical, and biological properties of soil are influenced by pH. • The pH of mineral soils is normally determined in slurries of water and soil sample by potentiometric measurements. • The association of LIBS elemental emissions with multivariate strategies of analysis has become LIBS a powerful technique. • LIBS was unprecedentedly applied for direct pH determination in different kinds of soil sample. • The clean and fast proposed

  12. Laser-induced breakdown spectroscopy: Extending its application to soil pH measurements

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Edilene Cristina, E-mail: edilene@iq.unesp.br [São Paulo State University – UNESP, Analytical Chemistry Department, Rua Prof. Francisco Degni 55, CEP 14800-060, Araraquara, SP (Brazil); Gomes Neto, José A. [São Paulo State University – UNESP, Analytical Chemistry Department, Rua Prof. Francisco Degni 55, CEP 14800-060, Araraquara, SP (Brazil); Milori, Débora M.B.P.; Ferreira, Ednaldo José [Embrapa Agricultural Instrumentation, Rua XV de Novembro 1452, CEP 13560-970, São Carlos, SP (Brazil); Anzano, Jesús Manuel [Laser Laboratory & Environment, Faculty of Sciences, University of Zaragoza, C/. Pedro Cerbuna 12, 50009, Zaragoza (Spain)

    2015-08-01

    Acid–base equilibria are involved in almost all the processes that occur in soil. The bioavailability of nutrients for plants, for instance, depends on the solubilization of mineral nutrients in the soil solution, which is a pH-dependent process. The determination of pH in soil solutions is usually carried out by potentiometry using a glass membrane electrode, after extracting some of the soil components with water or CaCl{sub 2} solution. The present work describes a simple method for determining the pH of soil, using laser-induced breakdown spectroscopy (LIBS). Sixty samples presenting different textural composition and pH (previously determined by potentiometry) were employed. The samples were divided into a calibration set with fifty samples and a validation set with ten samples. LIBS spectra were recorded for each pelleted sample using laser pulse energy of 115 mJ. The intensities of thirty-two emission lines for Al, Ca, H, and O were used to fit a partial least squares (PLS) model. The model was validated by prediction of the pH of the validation set samples, which showed good agreement with the reference values. The prediction mean absolute error was 0.3 pH units and the root mean square error of the prediction was 0.4. These results highlight the potential of LIBS for use in other applications beyond elemental composition determinations. For soil analysis, the proposed method offers the possibility of determining pH, in addition to nutrients and contaminants, using a single LIBS measurement. - Highlights: • Physical, chemical, and biological properties of soil are influenced by pH. • The pH of mineral soils is normally determined in slurries of water and soil sample by potentiometric measurements. • The association of LIBS elemental emissions with multivariate strategies of analysis has become LIBS a powerful technique. • LIBS was unprecedentedly applied for direct pH determination in different kinds of soil sample. • The clean and fast proposed

  13. Forum for Almen Medicinske ph.d.-studerende

    DEFF Research Database (Denmark)

    Vedsted, Peter; Waldorff, Frans Boch; Eriksson, Tina

    Rapport fra første fællesmøde mellem nuværende og kommende almenmedicinske ph.d.-studerende. Rapporten anbefaler dannelse af et egentligt almenmedicinsk ph.d.-forum, der søges optaget i DSAM som en interessegruppe. Ph.d.-forum betragter sig som en ressource ved forskellige initiativer og ønsker...... blandt andet at arbejde for en værdig ansættelse af yngre forskere. Blandt de konkrete forslag, Ph.d.-forum har stillet, er almenmedicinske ph.d.-kurser og ph.d.-stipendium med henblik på udarbejdelse af protokol....

  14. Regulation of antigen presentation by acidic pH

    OpenAIRE

    1990-01-01

    The effect of pH on functional association of peptide antigens with APC membranes was investigated by using aldehyde-fixed B cells and class II- restricted T cell hybridomas to assess antigen/MHC complex formation. The results indicated that the rate and extent of functional peptide binding was markedly increased at pH 5.0 as compared with pH 7.3. The pH dependence of binding was preserved after pretreatment of fixed APC with pH 5.0 buffer, suggesting that pH had a direct effect on the intera...

  15. Sociale media als leermiddel

    NARCIS (Netherlands)

    Rubens, Wilfred

    2012-01-01

    Rubens, W. (2012, 5 juni). Sociale media als leermiddel. Presentatie over het gebruik van sociale media binnen het onderwijs, verzorgd tijdens een ouderraadbijeenkomst van de Katholieke Scholengemeenschap Etten-Leur, Etten-Leur, Nederland.

  16. MDA ALS Caregiver's Guide

    Science.gov (United States)

    ... R.D., C.N.S.D., L.D.N. Nutritionist MDA/ALS Center at Vanderbilt University Medical Center ... neurologists, physiatrists, therapists (physical, occupa- tional, speech, respiratory), nutritionists, social work- ers, pulmonologists, gastroenterologists and medical equipment ...

  17. Regionale Herkunft als Bonus

    OpenAIRE

    Kratochvil, Dr. Ruth

    2004-01-01

    Der Bio-Sektor durchlebt bewegte Zeiten. Die biologische Landwirtschaft hat sich aus der Nische herausbewegt und dafür an „Besonderheiten“ eingebüßt. Diese müssen als Zusatznutzen wiedergefunden werden.

  18. Partizipation als Ausnahmezustand

    OpenAIRE

    Korf, Benedikt

    2009-01-01

    In «Die Erfindung des Politischen» (1993) beschreibt Ulrich Beck Subpolitik als den Ort, an dem die Grenze zwischen Politik und Nichtpolitik verschwindet. Aus der zunehmenden Wirkkraft von Subpolitik erwächst die grundlegende Frage, mit welcher Legitimation diese Art von Subpolitik in die Sphäre der institutionalisierten Politik eindringt. Beck’s Subpolitik soll im Anschluss an theoretische Arbeiten von Chantal Mouffe und Giorgio Agamben als post-politische Aspiration bezeichnet werden, die e...

  19. Der Preis als Kaufbarriere?

    DEFF Research Database (Denmark)

    Mueller Loose, Simone

    2012-01-01

    Die Preispolitik hat eine herausragende Stellung im Marketing. Der Preis eines Produktes ist für Verbraucher ein direkter Kostenfaktor und für Unternehmen die Stellgröße im Mar-ketingmix, die den Umsatz am stärksten beeinflusst (vgl. Nieschlag et al. 2002). Wenn die Akzeptanz und der regelmäßige...... Verzehr gesunder Lebensmittel erhöht werden soll, ist es sowohl für die Verbraucherpolitik als auch für Lebensmittelproduzenten wichtig, den Ein-fluss des Preises auf die Kaufentscheidung zu verstehen. Aus Verbrauchersicht ist der Preis neben dem Geschmack die wichtigste Produkteigen-schaft beim Kauf von...... Lebensmitteln (vgl. Brunsø/Grunert 1998) und stellt eine Kaufbarrie-re für Lebensmittel mit gesundheitsfördernden Eigenschaften dar. Studien in den USA (vgl. Cassady et al. 2007), Frankreich (vgl. Drewnowski et al. 2004; Andrieu et al. 2005) und Deutschland (vgl. Karg et al. 2008) kommen übereinstimmend zu dem...

  20. Metal extraction from Cetraria islandica (L. Ach. lichen using low pH solutions

    Directory of Open Access Journals (Sweden)

    ANA A. CUCULOVIC

    2008-04-01

    Full Text Available Extraction of metals (K, Al, Ca, Mg, Fe, Cu, Ba, Zn, Mn and Sr from dry Cetraria islandica (L. Ach. lichen was performed using solutions similar to acid rain (solution A – H2SO4–HNO3–(NH42SO4 and solution B – H2SO4–HNO3–(NH42SO4–NH4NO3. The pH values of these solutions were 2.00, 2.58, 2.87, 3.28, and 3.75. Five consecutive extractions were performed with each solution. In all solutions, the extracted metal content, except Cu and Ca, was the highest in the first extract. The highest percentage of the metals desorbed in the first extraction was obtained using solutions with low pH values, 2.00, 2.58, and 2.87. The lowest percentage in the first extraction was obtained using solutions with pH 3.28 and 3.75, indicating influence of the H+ ion on the extraction. According to the results obtained, the investigated metals form two groups. The first group includes K, Al, Ca, Mg, and Fe. They were extracted in each of the five extractions at each of the pH values. The second group includes Ba, Zn, Mn, Cu, and Sr, which were not all extracted at each pH value. The first group yielded three types of extraction curves when the logarithms of extracted metal amounts were plotted as a function of the number of successive extractions. These effects indicate that three different positions (centres of metal ion accumulation exist in the lichen (due to sorption, complex formation, or other processes present in the tissues.

  1. Effects of PVA and PEG on pH Dependent Shear Yield Stress of Concentrated Alumina Suspensions

    Institute of Scientific and Technical Information of China (English)

    ZHENGRenjie; B.RAND

    2002-01-01

    The pH dependence of the extrapolated shear yield stress for Alcoa A16 α-Al2O3 suspensions at the powder volume fraction of 0.27 with and without addition of both polyvinyl alcohol (PVA) and polyethylene glycol (PEG) each at fixed 0.18% of the powder mass was studied. Whith the polymer added, the full deflocculation of the suspension shifts from about pH=4 to around pH=1.5, at which the minimum value of shear yied stress is higher than that at pH=4. The addition of both PVA and PEG was found to prevent the filter cake from cracking.

  2. Microscopic measurement of pH with iridium oxide microelectrodes

    Science.gov (United States)

    Wipf; Ge; Spaine; Baur

    2000-10-15

    Microscopic pH electrodes were produced by deposition of hydrous iridium oxide onto carbon fiber microelectrodes. The electrodes exhibit two linear regions of potentiometric response between pH 2-6 and pH 6-12. The electrodes respond to pH changes within 50 ms, and an equilibrium value is reached within 30 s. By using these electrodes as probes in the scanning electrochemical microscope, dynamic pH changes occurring at or near a surface can be measured and pH maps of the surface can be generated. Vertical pH profiles and images of pH were obtained at substrates where electrochemical (oxidation and reduction of H2O2, hydrogen evolution) or enzymatic (glucose oxidase) reactions involving proton transfers occur. PMID:11055710

  3. Sequestration of uranium on fabricated aluminum co-precipitated with goethite (Al-FeOOH)

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yubing; Yang, Shubin; Wang, Qi; Wang, Xiangke [Chinese Academy of Science, Hefei (China). Key Laboratory of Novel Thin Film Solar Cells; Alsaedi, Ahmad [King Abdulaziz Univ., Jeddah (Saudi Arabia). Nonlinear Analysis and Applied Mathematics (NAAM) Research Group

    2014-11-01

    Aluminum co-precipitated with goethites (Al-FeOOHs) are ubiquitous within (sub)-surface environments, which are considered one of the most important sinks for radionuclide pollution management. Accordingly, various mole ratios Al-FeOOH were synthesized and characterized by XRD, FT-IR, TEM, specific surface area and potentiometric acid-base titration. According to XRD and TEM images, the morphology of Al-FeOOH was transformed from acicular-like goethite to cotton-like gibbsite with increasing Al content. The adsorption and sequential desorption of U(VI) on Al-FeOOHs were conducted by batch techniques under N{sub 2} conditions. The batch adsorption results showed that the adsorption of U(VI) on Al-FeOOHs slightly increased at pH < 4.0, then the significant increase of U(VI) adsorption was observed at pH from 4.0 to 7.0, whereas the suppressed adsorption at pH > 8.0 was due to the electrostatic repulsion between negative charge surface and negative carbonato-complexes. The adsorption of U(VI) on Al-FeOOHs was independent of ionic strength at pH > 5.0, indicating that the inner-sphere surface complexation predominated their adsorption behaviors, whereas U(VI) adsorption on Al-FeOOH could be the outer-sphere surface/cation exchange reaction. The sequential extraction texts showed that the desorption of U(VI) from Al-FeOOHs decreased with increasing Al content. These findings highlighted the effect of Al content on the sequestration and immobilization of U(VI) onto Al-FeOOHs from (sub)-surface environments in pollution management.

  4. EVALUATION OF A NEW CATHETER FOR ESOPHAGEAL PH MONITORING

    NARCIS (Netherlands)

    KUIT, JA; SCHEPEL, SJ; BIJLEVELD, CMA; KLEIBEUKER, JH

    1991-01-01

    A new catheter, provided with an Ion Sensitive Field Effect Transistor as a pH sensor and incorporating a reference electrode, was evaluated for esophageal pH recording. The pH-sensitivity was 54 mV/pH in vitro, with a linear response between pH 2 and pH 9. Clinical semi-ambulatory 24-hour esophagea

  5. Modification of residual stress in Al-[AlBO]w/Al compound plate

    Institute of Scientific and Technical Information of China (English)

    姜传海; 吴建生; 王德尊

    2001-01-01

    The application of compound parts of Al-[AlBO]w/Al not only reduces the cost of the parts but also improves its properties. However, there is a large thermal residual stress between Al and [AlBO]w/Al, and it is harmful for practical application. From the theoretical analyses and experimental results, it was found that by the compressive pre-plastic deformation perpendicular to the interface between Al and [AlBO]w/Al, the interlayer residual stress of compound parts can be reduced, while the mechanical properties of compound parts can be improved.

  6. Changes in the size of the apparent surface area and adsorption energy of the rye roots by low pH and the presence of aluminium ions induced

    Science.gov (United States)

    Szatanik-Kloc, Alicja

    2016-07-01

    The plant reactions on Al-stress include i.a. change of the surface area of the roots, which in the physicochemistry of plants characterizes the transport of water and ions through the root. The object of this study is the specific surface area of the roots of plants which are tolerant to aluminium, such as rye. Plants of rye were grown in a nutrient solution for 14 days at pH 4.5 in the presence of Al3+ ions of concentration 10, 20, and 40 mg dm-3. The control plants were grown continuously at pH 7 or pH 4.5 without Al3+. The apparent surface area and adsorption energy of the plants roots were determined from water vapour adsorption - desorption data. The apparent surface area of roots growing in the aluminium was (with respect to control) statistically significantly lower. There were no statistically significant differences in the apparent surface area of the roots which grew in pH 7, pH 4.5 without Al3+. The average water vapour adsorption energy of the root surface, under stress conditions decreased. In the roots grown in the presence of Al+3, there was a slight decrease in high energy adsorption centres and an increase in the amount of low-energy centres.

  7. Higher pH acid stimulation systems

    Energy Technology Data Exchange (ETDEWEB)

    Abrams, A.; Richardson, E.A.; Scheuerman, R.F.; Templeton, C.C.

    1979-01-01

    Two types of high pH (4 to 6), mild acting acidizing systems developed for in-depth rock matrix stimulation for both sandstone and carbonate reservoirs are described. With these systems, in-depth stimulation capability is available from ambient to about 280 F (138 C). Buffer regulated (BR) systems also have application for near well-bore stimulation at temperatures of up to at least 365 F (185 C). The self-generating systems based on methyl formate (MF), the ammonium salt of monochloroacetic acid (CA), and methyl acetate (MA), have sandstone application ranges and are described. Three BR systems have been developed, based on formic, acetic, and citric acids. Included in the study is a brief review of the theory involved, experimental techniques for measuring acid reaction rates, and discussions of clay dissolution and carbonate acidization mechanisms. 16 references.

  8. PH Department: at the heart of CERN

    CERN Multimedia

    Antonella Del Rosso

    2014-01-01

    The Physics Department is where the Laboratory’s scientific activity takes place. Some 1000 members of the personnel and 11,000 users work together on CERN’s highly diversified experimental programme. The challenges for the coming years are twofold: maintain the level of excellence that led the Laboratory to the discovery of the Higgs boson, and preserve the diversity of the scientific programme. The new Department Head discusses his vision with us.   Livio Mapelli. “On paper, our plan for the next two years shows no surprises,” says Livio Mapelli, former Deputy Department Head and now, since January, Head of the Physics Department (PH). “We have to finish the completion, consolidation and initial upgrades of the experiments planned for LS1. In 2015, our core activity will be supporting the experiments during the restart of the accelerator complex. However, as physicists, the best reward for us would be to obtain new breakthroughs and importa...

  9. Fortschritt als Fortschrittsdiskurs

    Directory of Open Access Journals (Sweden)

    Rainer Schmid-Zartner

    2014-12-01

    Full Text Available Zur Erzielung gesellschaftlichen Fortschritts in demokratisch verfassten Gesellschaften soll die Möglichkeit am Fortschrittsdiskurs teilnehmen zu können für alle Mitglieder der Gesellschaft als selbstverständliche Prämisse gelten. Fortschritt wird also als Bewusstseinsbildung dem Fortschritt selbst gegenüber und als Entscheidungs- und Handlungsfähigkeit auf individueller und gesellschaftlicher Ebene definiert. Dies setzt entsprechende Maßnahmen zur Befähigung dazu voraus, die alle Mitglieder der Gesellschaft erfassen. Dabei ist der Bildungsbereich angesprochen, insbesondere der Schulunterricht. Neben dem in der aktuellen blidungspolitischen Debatte forcierten Fokus auf den Aspekt der Kompetenzorientierung, der hier nicht infrage gestellt wird, ist als notwendige Ergänzung ein reflexionsorientierter Schulunterricht in allen Bildungsfächern einzufordern und umzusetzen. Im Weiteren beschreibt der Text den Weg von der Brauchbarkeit zur Bedeutsamkeit von schulischem Wissen durch Relevanzreflexionsprovokationen im Schulunterricht, um Sinn und Bedeutung der vermittelten Bildungsinhalte zu verhandeln. Am Beispiel von Mathematik als Bildungsfach wird der Inhalt von reflexionsorientertem Unterricht verdeutlicht. Darüber hinaus beschreibt der Text eine Reihe von konkreten Fallbeispielen aus der aktuell versuchsweise durchgeführten Unterrichtspraxis in Mathematik.

  10. Acid Rain, pH & Acidity: A Common Misinterpretation.

    Science.gov (United States)

    Clark, David B.; Thompson, Ronald E.

    1989-01-01

    Illustrates the basis for misleading statements about the relationship between pH and acid content in acid rain. Explains why pH cannot be used as a measure of acidity for rain or any other solution. Suggests that teachers present acidity and pH as two separate and distinct concepts. (RT)

  11. pH of organ-culture-stored corneas.

    Science.gov (United States)

    Lass, J H; Greiner, J V; Meneses, P; Morgan, D C; Medcalf, S K; Collie, D M; Skelnik, D L; Glonek, T

    1988-10-01

    Changes in intracorneal and storage-medium pH values of organ-culture-stored cat corneas were monitored over a 4-week period. The intracorneal pH was determined using the phosphorus-31 magnetic resonance spectroscopy (31P MRS) chemical shift of inorganic orthophosphate in conjunction with a standard pH titration curve. We incubated 32 adult cat corneas using two similar standard organ-culture methods, one with chondroitin sulfate (method 1) and the other without (method 2). Time-course data at 0, 1, 3 and 4 weeks of storage were used to calculate the rate of pH change. The intracorneal pH was not changed significantly for either organ-culture method; however, the storage-medium pH rate of change declined significantly for both methods (method 1, 0.15 pH units/week; method 2, 0.12 pH units/week). The difference between intracorneal and storage-medium pH values over time increased at a rate of 0.12 and 0.11 pH units/week for method 1 and method 2, respectively. The declining storage-medium pH in conjunction with the maintenance of intracorneal pH contributes to an increased metabolic demand on the cornea. PMID:3218477

  12. Proces og struktur i ph.d.-forløbet

    DEFF Research Database (Denmark)

    Kristensen, Nete Nørgaard; From, Unni

    Bogen giver et indblik i ph.d.-forløbet fra både faglige og personlige vinkler og udpeger problemstillinger og faldgruber - muligheder, potentialer og spændende oplevelser, der knytter sig til livets som ph.d.-stipendiat. Bogen rummer bidrag fra såvel ph.d.-studerende og seniorforskere og sætter...

  13. Electrochemical Corrosion Behaviour of Alumina-Al 6061 and Silicon Carbide-Al 6061 Metal-Matrix Composites

    International Nuclear Information System (INIS)

    The electrochemical corrosion behaviour of powder metallurgy-processed metal-matrix composites (MMCs)based on Al alloy 6061 reinforced with particulate Al2O3 or Sic has been studied in chloride-containing environment. Also, the corrosion behaviour of the unrein forced Al 6061 produced by the same route investigated. Electrochemical tests were conducted on composites containing 10 and 20 vo l% of both reinforced particulates. Potentiodynamic polarization tests have been carried out in neutral as well as acidic and alkaline de-aerated 10-3M Na CI solution. In the neutral environment, the addition of Al2O3 particulates was found to shift both the corrosion potential (Ecorr) and the break down potential (Eb) slightly into the positive direction irrespective of the volume fraction added (10 and 20 vo l%). On the other hand , Sic caused a shift of Ecorr into the active site while the Eb value was slightly ennobled. For both composites, the corrosion current values at the break down potentials were almost the same as the unrein forced alloy. In an attempt to further clarify the role of both particulate addition, cathodic polarization runs were conducted in both acidic (ph 3) and alkaline (ph 9)solutions for 20 vo l% of Al2O3 and 20 vo l% Sic composite specimens. This indicated that cathodic current values for Sic composites were higher than those corresponding to the unrein forced alloy 6061, and those for the Al2O3 composites were lower

  14. Understanding Non-Traditional PhD Students Habitus--Implications for PhD Programmes

    Science.gov (United States)

    Naidoo, Devika

    2015-01-01

    Against the background of vast changes in doctoral education and the emergence of non-traditional doctoral programmes, this paper investigates the habitus of non-traditional PhD students at a South African university. Bourdieu's conceptual tool of habitus informed the study. In-depth and open-ended interviews were conducted with 10 non-traditional…

  15. Influence of pH on the thixotropy of magnesium aluminum hydroxide-kaolinite suspension

    Institute of Scientific and Technical Information of China (English)

    DAI; Xiaonan

    2001-01-01

    [1]Chen Zongqi, Shi Lin, Wu Shiying et al., The negative thixotropy, Chemistry (in Chinese), 1991, 54(2): 31-34.[2]Hou Wanguo, Sun Dejun, Han Shuhua et al., A novel thixotropic phenomenon-complex thixotropic behavior, Chem. Res. Chin. Univ., 1997, 13(1): 86-88.[3]Mo 2+ Al3+[4]Constantino. V. R. L., Pinnavaia, T. J., Basic properties of Mg2+l-x Ai3+x layered double hydroxides intercalated by carbonate. hydroxide, chloride, and sulfate anions, Inorg. Chem., 1995, 34(4): 883-892.[5]Albiston, L., Frankin, K. R., Lee, E. et al., Rheology and microstructure of aqueous layered double hydroxide dispersions, J. Mater. Chem., 1996, 6(5): 871-877.[6]Abend, S., Bonnke, N., Gutschner, U. et al., Stabilization of emulsions by heterocoagulation of clay minerals and layered double hydroxides, Colloid Polym. Sci., 1998, 276(8): 730-737.[7]Heckroodt, R. O., Ryan, W., Clay suspensions with negative thixotropy, Trans. J. Brit. Ceram. Sci., 1978, 77(2): 180- 183.[8]Chen Zongqi, Yu Wanglin, Hao Ce et al., The rheological properties of SiO2 suspension and PHPA system, Acta Chimica Sinica, 1990, 48(7): 666-72.[9]Benna, M., Kbir-Ariguib, N., Magnin, A. et al., Effect of pH on rheological properties of purified sodium bentonite suspensions, J. Colloid Interface Sci., 1999, 218(4): 442-445.[10]Sohm, R., Tadros, T. F., Viscoelastic Properties of sodium montmorillonite (Gelwhite H) suspensions, J. Colloid Interface Sci.. 1989, 132(1): 62-71.[11]Torrance, K. J., Pirmat, M., Effect of pH on the rheology of marine clay from the site of the south Nation River, Clays Clay Miner, 1984, 32(5): 384-390.[12]Heath, D., Tadros, T. F., Influence of pH, electrolyte, and poly (vinyl alcohol) addition on the rheological characteristics of aqueous dispersions of sodium montmorillonite, J. Colloid Interface Sci., 1983, 93(2): 307-319.

  16. Relation between pH in the Trunk and Face: Truncal pH Can Be Easily Predicted from Facial pH

    OpenAIRE

    Kim, Sung Ae; Kim, Bo Ri; Chun, Mi Young; Youn, Sang Woong

    2016-01-01

    Background The clinical symptoms of facial and truncal acne differ. Skin surface acidity (pH), which is affected by sebum secretions, reflects the different clinical characteristics of the face and trunk. However, no studies have been conducted on truncal sebum production and skin pH. Objective We evaluated the differences and relationship between pH values of the face and trunk. We also evaluated the relationship between pH and the quantity of sebum produced in the trunk. Methods A total of ...

  17. Laser-induced breakdown spectroscopy: Extending its application to soil pH measurements

    Science.gov (United States)

    Ferreira, Edilene Cristina; Gomes Neto, José A.; Milori, Débora M. B. P.; Ferreira, Ednaldo José; Anzano, Jesús Manuel

    2015-08-01

    Acid-base equilibria are involved in almost all the processes that occur in soil. The bioavailability of nutrients for plants, for instance, depends on the solubilization of mineral nutrients in the soil solution, which is a pH-dependent process. The determination of pH in soil solutions is usually carried out by potentiometry using a glass membrane electrode, after extracting some of the soil components with water or CaCl2 solution. The present work describes a simple method for determining the pH of soil, using laser-induced breakdown spectroscopy (LIBS). Sixty samples presenting different textural composition and pH (previously determined by potentiometry) were employed. The samples were divided into a calibration set with fifty samples and a validation set with ten samples. LIBS spectra were recorded for each pelleted sample using laser pulse energy of 115 mJ. The intensities of thirty-two emission lines for Al, Ca, H, and O were used to fit a partial least squares (PLS) model. The model was validated by prediction of the pH of the validation set samples, which showed good agreement with the reference values. The prediction mean absolute error was 0.3 pH units and the root mean square error of the prediction was 0.4. These results highlight the potential of LIBS for use in other applications beyond elemental composition determinations. For soil analysis, the proposed method offers the possibility of determining pH, in addition to nutrients and contaminants, using a single LIBS measurement.

  18. Pornographie als Metapher

    Directory of Open Access Journals (Sweden)

    Caroline Schubarth

    2010-03-01

    Full Text Available In diesem Artikel werden unterschiedliche metaphorische Verwendungen des Pornografiebegriffs und deren Implikationen untersucht. Während die Existenz von Pornografie der feministischen Anti-Porno-Bewegung als Erklärung für die anhaltende Diskriminierung von Frauen in westlichen Gesellschaften dient, nutzen rechtskonservative Kräfte den Pornografievorwurf als Rechtfertigung für die Zensur von als deviant empfundenen Identitäten und sexuellen Praktiken.This article examines different metaphorical uses of the term pornography and the resulting implications. While the existence of pornography for the feminist anti-porno movement serves as factor in the continuing discrimination of women in western societies, conservative powers on the right use the allegation of pornography as a justification for censorship of those identities and sexual practices deemed deviant.

  19. Wikipedia als Referenzorgan

    OpenAIRE

    Voß, Jakob

    2006-01-01

    Wikipedia wird inzwischen von vielen Nutzern regelmäßig als Nachschlagewerk genutzt. Aufgrund des offenen Charakters der Online-Enzyklopädie, bei der sich jeder direkt beteiligen kann, ist jedoch zusätzliche Medienkompetenz notwendig, um die Qualität einzelner Wikipedia-Artikel einschätzen zu können. Im Vortrag sollen Methoden zur Beurteilung von Wikipedia-Artikeln dargestellt und die Frage beleuchtet werden, unter welchen Umständen Wikipedia als Referenzorgan geeignet ist.

  20. Carta al Editor

    Directory of Open Access Journals (Sweden)

    José Andrés Burgos Zuleta

    2010-06-01

    Full Text Available La medicina al basarse generalmente en la clínica, correlacionaexámenes complementarios y organiza un diagnóstico y tratamiento, es una disciplina donde es imprescindible saber recolectar, analizar, interpretar y concretar una respuesta adecuada, es así que la información que se recibe es esencial para el desempeño médico.La certeza es una realidad que se da en algunas situaciones y enotras las probabilidades establecen conclusiones. Lo normal muchas veces se define sobre la base de criterios estadísticos, basados en riesgos poblacionales que no necesariamente se aplican al caso boliviano.

  1. Ratiometric Imaging of Extracellular pH in Dental Biofilms

    DEFF Research Database (Denmark)

    Schlafer, Sebastian; Dige, Irene

    2016-01-01

    allows monitoring both vertical and horizontal pH gradients in real-time without mechanically disturbing the biofilm. However, care must be taken to differentiate accurately between extra- and intracellular compartments of the biofilm. Here, the ratiometric dye, seminaphthorhodafluor-4F 5-(and-6...... of extracellular pH. After confocal microscopic image acquisition, the bacterial biomass is removed from all pictures using digital image analysis software, which permits to exclusively calculate extracellular pH. pH ratiometry with the ratiometric dye is well-suited to study extracellular pH in thin biofilms...

  2. Intracellular pH of acid-tolerant ruminal bacteria.

    OpenAIRE

    Russell, J B

    1991-01-01

    Acid-tolerant ruminal bacteria (Bacteroides ruminicola B1(4), Selenomonas ruminantium HD4, Streptococcus bovis JB1, Megasphaera elsdenii B159, and strain F) allowed their intracellular pH to decline as a function of extracellular pH and did not generate a large pH gradient across the cell membrane until the extracellular pH was low (less than 5.2). This decline in intracellular pH prevented an accumulation of volatile fatty acid anions inside the cells.

  3. pH distributions in spontaneous and isotransplanted rat tumours.

    OpenAIRE

    Kallinowski, F; Vaupel, P

    1988-01-01

    Spontaneous mammary tumours of the rat with various degrees of malignancy exhibit similar tissue pH distributions. The mean pH (+/- s.d.) of dysplasia is 7.05 +/- 0.20. In benign tumours the mean pH is 6.95 +/- 0.19 and in malignant tumours it is 6.94 +/- 0.19. In contrast, tumours with the same degree of malignancy but different histologies show different pH distributions. Benign tumours with a higher percentage of fibrous tissue exhibit less acidic pH values than those with larger portions ...

  4. The Role of pH Regulation in Cancer Progression.

    Science.gov (United States)

    McIntyre, Alan; Harris, Adrian L

    2016-01-01

    Frequently observed phenotypes of tumours include high metabolic activity, hypoxia and poor perfusion; these act to produce an acidic microenvironment. Cellular function depends on pH homoeostasis, and thus, tumours become dependent on pH regulatory mechanisms. Many of the proteins involved in pH regulation are highly expressed in tumours, and their expression is often of prognostic significance. The more acidic tumour microenvironment also has important implications with regard to chemotherapeutic and radiotherapeutic interventions. In addition, we review pH-sensing mechanisms, the role of pH regulation in tumour phenotype and the use of pH regulatory mechanisms as therapeutic targets. PMID:27557536

  5. Time course of pH change in plant epidermis using microscopic pH imaging system

    Science.gov (United States)

    Dan, Risako; Shimizu, Megumi; Kazama, Haruko; Sakaue, Hirotaka

    2010-11-01

    We established a microscopic pH imaging system to track the time course of pH change in plant epidermis in vivo. In the previous research, we have found out that anthocyanin containing cells have higher pH. However, it was not clear whether the anthocyanin increased the pH or anthocyanin was synthesized result from the higher pH. Therefore, we further investigated the relationship between anthocyanin and pH change. To track the time course of pH change in plant epidermis, we established a system using luminescent imaging technique. We used HPTS (8-Hydroxypyrene-1,3,6-Trisulfonate) as pH indicator and applied excitation ratio imaging method. Luminescent image was converted to a pH distribution by obtained in vitro calibration using known pH solution. Cellular level observation was enabled by merging microscopic color picture of the same region to the pH change image. The established system was applied to epidermal cells of red-tip leaf lettuce, Lactuca Sativa L. and the time course was tracked in the growth process. We would discuss about the relationship between anthocyanin and pH change in plant epidermis.

  6. Preparation of Pseudo-boehmite and γ-Al2O3 Support by Neutralization of NaAlO2 Solution with CO2

    Institute of Scientific and Technical Information of China (English)

    Yang Qinghe; Liu Bin; Li Dadong; Shi Yahua; Nie Hong; Kang Xiaohong

    2003-01-01

    Pseudo-boehmite (PB) and γ-Al2O3 support are prepared by neutralization ofNaAlO2 solution with CO2(mixed gases) on bench scale. PB, typically loosely packed, fibrous particle/aggregate, is obtained by adjustingconcentration and flow rate of CO2 and concentration of NaAlO2 solution at a pH level lower than that commonlyassumed during neutralization. After calcination at different temperatures, γ-Al2O3 supports with different pore vol-ume and different pore size are prepared at different conditions.

  7. Acid-induced folding of yeast alcohol dehydrogenase under low pH conditions.

    Science.gov (United States)

    Le, W P; Yan, S X; Zhang, Y X; Zhou, H M

    1996-04-01

    Under conditions of low pH, the conformational states of holo-YADH and apo-YADH were examined by protein intrinsic fluorescence, ANS fluorescence, and far-UV CD measurements. The results obtained show that a low ionic strength, with the addition of HCl, the holo- and apo- YADH denatured gradually to reach the ultimate unfolded conformation in the vicinity of pH 2.0 and 2.5, respectively. With the decrease of pH from 7.0 to 2.0, the fluorescence emission decreased markedly, with its emission maximum red-shifting from 335 to 355 nm, indicating complete exposure of the buried tryptophan residues to the solvent. The far-UV CD spectra show the loss of the arrayed secondary structure, though the acid-denatured enzyme still maintained a partially arrayed secondary structure. A further decrease in pH by increasing the concentration of HClO4 induced a cooperative folding of the denatured enzyme to a compact conformation with the properties of a molten globule, described previously by Goto et al. [Proc. Natl. Acad. Sci. USA 87, 573-577 (1990)]. More extensive studies showed that although apo-YADH and holo-YADH exhibited similar behavior, the folding cooperative ability of apo-YADH was lower than that of the holo-enzyme. From the above results, it is suggested that the zinc ion plays an important role in the proper folding of YADH and in stabilizing its native conformation.

  8. Surface degradation of dental ceramics as a function of environmental pH.

    Science.gov (United States)

    Esquivel-Upshaw, J F; Dieng, F Y; Clark, A E; Neal, D; Anusavice, K J

    2013-05-01

    We tested the hypotheses that glass-ceramic veneers and overglazes degrade by ion exchange in an acidic environment, and that they degrade by breakdown of the silica network in a basic environment. Disk specimens of glass-ceramic veneer and glaze were fabricated and immersed in pH 2, 7, or 10 buffer solutions, for 1, 3, 5, 10, 15, and 30 days. Each specimen was placed in a shaker bath containing de-ionized distilled water at 80°C. Concentrations of Al(3+), Ca(2+), Zn(2+), Li(2+), and Si(4+) were analyzed by means of inductively coupled plasma atomic emission spectrometry (ICP/AES). Statistical analyses were performed by factorial ANOVA. Significant differences occurred among leached ion concentrations as a function of material type, solution pH, and exposure time. A substantial release of Si occurred at pH 10 over time, leading to a breakdown of the glass phase. At pH 2, dissolution was controlled by an ionic exchange mechanism. We conclude that ceramic veneers and glazes may be susceptible to considerable degradation in low- and high-pH buffer solutions. PMID:23569159

  9. Fabrication and Characterization of a Ruthenium Nitride Membrane for Electrochemical pH Sensors

    Directory of Open Access Journals (Sweden)

    Yi-Hung Liao

    2009-04-01

    Full Text Available ThepH sensing and nonideal characteristics of a ruthenium nitride (RuN sensing membrane pH sensor were investigated. RuN thin films were deposited from a 99.9% ruthenium target on p-type silicon substrates using radio frequency (r.f. sputtering with N2 gas. Subsequently, the nanometric structure and surface morphology of RuN thin films were determined. The sensitivity of the RuN sensing membrane pH sensor was 58.03 mV/pH, obtained from ID-VG curves with a current-voltage (I-V measurement system in standard buffer solutions from pH 1 to pH 13 at room temperature (25 °C. Moreover, the nonideal characteristics of the RuN sensing membrane, such as temperature coefficient, drift with light influence, drift rate and hysteresis width, etc. were also investigated. Finally, the sensing characteristics of the RuN membrane were compared with titanium nitride (TiN, aluminum nitride (AlN and silicon nitride (Si3N4 membranes.

  10. pH titrations of molluscan paramyosin at two different ionic strengths.

    Science.gov (United States)

    Cooley, L B; Krause, S

    1980-11-01

    Paramyosin extracted from the adductor muscle of Mercenaria mercenaria, the chowder clam, was titrated both in 0.3 M KCl and in 1 mM KCl. Both the presumed native form of the molecule, acid-R-paramyosin, and a slightly degraded form, beta-paramyosin, were studied. Titrations of both types of paramyosin were similar in 1 mM k+, except that the native paramyosin is more highly charged at pH 3.2 than beta-paramyosin, as postulated previously (DeLaney and Krause, 1976, Macromolecules, 9:455), and that more groups titrate on the native molecule than on beta-paramyosin, both between pH 3.2 and 3.3 and between pH 3.2 and 10. Titrations in 0.30 M KCl, unlike those in 1 mM K, depended on starting pH; long term exposure to alkali solutions during dialysis, previously shown to cause partial dephosphorylation of paramyosin (Cooley et al., 1979, J. Biol. Chem., 254:2195), apparently also leads to a change in intermolecular interactions sufficient to cause changes in the titration curves in 0.30 M KCl but not in 1 mM K+.

  11. Influence of Al substitution on magnetism and adsorption properties of hematite

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Shanshan; Kang, Feifei; Yang, Xin; Zhen, Zhen [College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024 (China); Liu, Hui, E-mail: liuhuicn@126.com [College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024 (China); Key Laboratory of Inorganic Nanomaterial of Hebei Province, Shijiazhuang 050024 (China); Chen, Rufen [College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024 (China); Key Laboratory of Inorganic Nanomaterial of Hebei Province, Shijiazhuang 050024 (China); Wei, Yu, E-mail: weiyu@mail.hebtu.edu.cn [College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang 050024 (China); Key Laboratory of Inorganic Nanomaterial of Hebei Province, Shijiazhuang 050024 (China)

    2015-08-15

    A series of Al-substituted hematite was prepared. The structures and properties of as-prepared samples were characterized by various techniques. The magnetic property of the samples was determined and the adsorption of three dyes Acid Blue 74, Methylene Blue and Phenol Red onto the samples was investigated. The results showed that Al incorporation into the crystal structure of hematite occurs via isomorphous ionic substitution of Al for Fe. With increasing Al content, the particle size of samples decreases, the magnetization increases and the remanent magnetization remains unchanged. The coercivity of the samples increases with Al substitution up to n{sub Al}/n{sub Fe} 0.03, and then decreases as Al content further increases. Compared with Al-free hematite, Al-substituted samples exhibit better adsorption ability to all of the three dyes. The adsorption rates of the three dyes on the surface of Al substituted samples depend on the structure of dye, pH and Al content in hematite. - Graphical abstract: Effect of Al on the structure, magnetic properties and adsorption performance of hematite was investigated. - Highlights: • A series of Al-substituted α-Fe{sub 2}O{sub 3} was prepared. • Effect of Al content on the crystal structure and magnetic property of hematite was investigated. • Al-substituted hematite exhibits better adsorption ability than hematite.

  12. Influence of Al substitution on magnetism and adsorption properties of hematite

    International Nuclear Information System (INIS)

    A series of Al-substituted hematite was prepared. The structures and properties of as-prepared samples were characterized by various techniques. The magnetic property of the samples was determined and the adsorption of three dyes Acid Blue 74, Methylene Blue and Phenol Red onto the samples was investigated. The results showed that Al incorporation into the crystal structure of hematite occurs via isomorphous ionic substitution of Al for Fe. With increasing Al content, the particle size of samples decreases, the magnetization increases and the remanent magnetization remains unchanged. The coercivity of the samples increases with Al substitution up to nAl/nFe 0.03, and then decreases as Al content further increases. Compared with Al-free hematite, Al-substituted samples exhibit better adsorption ability to all of the three dyes. The adsorption rates of the three dyes on the surface of Al substituted samples depend on the structure of dye, pH and Al content in hematite. - Graphical abstract: Effect of Al on the structure, magnetic properties and adsorption performance of hematite was investigated. - Highlights: • A series of Al-substituted α-Fe2O3 was prepared. • Effect of Al content on the crystal structure and magnetic property of hematite was investigated. • Al-substituted hematite exhibits better adsorption ability than hematite

  13. Skin pH, Atopic Dermatitis, and Filaggrin Mutations

    DEFF Research Database (Denmark)

    Bandier, Josefine; Johansen, Jeanne Duus; Petersen, Lars Jelstrup;

    2014-01-01

    mutations may influence skin pH. OBJECTIVE: We aimed to determine the epidermal pH in different groups stratified by filaggrin mutations and atopic dermatitis. Further, we investigated the changes in pH according to severity of mutational status among patients with dermatitis, irrespective of skin condition....... METHODS: pH was measured with a multiprobe system pH probe (PH 905), and the study population was composed of 67 individuals, who had all been genotyped for 3 filaggrin mutations (R501X, 2282del4, R2447X). RESULTS: We found no clear pattern in relation to filaggrin mutation carrier status. Individuals...... with wild-type filaggrin displayed both the most acidic and most alkaline values independent of concomitant skin disease; however, no statistical differences between the groups were found. CONCLUSIONS: The lack of significant diversity in skin pH in relation to filaggrin mutation carrier status suggests...

  14. pH in atomic scale simulations of electrochemical interfaces

    DEFF Research Database (Denmark)

    Rossmeisl, Jan; Chan, Karen; Ahmed, Rizwan;

    2013-01-01

    Electrochemical reaction rates can strongly depend on pH, and there is increasing interest in electrocatalysis in alkaline solution. To date, no method has been devised to address pH in atomic scale simulations. We present a simple method to determine the atomic structure of the metal|solution in......Electrochemical reaction rates can strongly depend on pH, and there is increasing interest in electrocatalysis in alkaline solution. To date, no method has been devised to address pH in atomic scale simulations. We present a simple method to determine the atomic structure of the metal......|solution interface at a given pH and electrode potential. Using Pt(111)|water as an example, we show the effect of pH on the interfacial structure, and discuss its impact on reaction energies and barriers. This method paves the way for ab initio studies of pH effects on the structure and electrocatalytic activity...

  15. Preferred pH of silver catfish Rhamdia quelen acclimated to different pH levels pH preferencial em jundiás Rhamdia quelen aclimatados em diferentes níveis de pH

    OpenAIRE

    Ana Paula Konzen Riffel; Sinara Jardim; Marcela Ciprandi Pires; Bruna Bertagnolli; Bruna Renata Silva Corrêa; Francine Cenzi de Ré; Francis Maria Bao Zambra; Greice Lubini; Luciano de Oliveira Garcia; Bernardo Baldisserotto

    2012-01-01

    The aim of this study was to investigate the preferred pH in silver catfish Rhamdia quelen acclimated to different pH. Fish were acclimated for one week at pH 4.2±0.1, 5.2±0.1, 6.3±0.1, 7.2±0.1, 8.0±0.1, and 9.0±0.1 and after this period, transferred to a polyethylene tube with a pH gradient from 3.5 to 10.0. The position of the fish in the pH gradient was observed 1, 6 and 12 hours after transference. Results indicated that acclimation to different pH did not change pH preference of silver c...

  16. Biomedical PhD education - an international perspective

    DEFF Research Database (Denmark)

    Mulvany, Michael J.

    2013-01-01

    . The situation has thus created a paradox. On the one hand, it has become essential for institutions to have many PhD students and for the research performed to be of the highest level. On the other hand, the careers of PhD students are not necessarily going to be directly related to the research performed......The PhD, otherwise known as the doctor of philosophy or Dr. Phil., is an internationally recognized degree, indicating that the PhD graduate has received training in research under supervision. Traditionally, the PhD was the route to an academic career, with most successful PhD graduates receiving...... tenured university positions. However, over the past 20–30 years, and particularly the past 10 years, the situation has changed dramatically. Governments in many countries have invested massively in PhD education, believing that trained researchers will contribute to the ‘knowledge society’, and thus...

  17. Calculation of interaction of AlCl, AlCl2 and AlCl3 on Al4C3 (001) Al4CO4 (001) and Al2CO (001) planes

    Institute of Scientific and Technical Information of China (English)

    段少飞; 陈秀敏; 杨斌; 郁青春; 徐宝强; 刘大春

    2015-01-01

    To make sure the intermediate products of the carbothermic reduction of Al2O3 process, such as Al4CO4, Al2CO and Al4C3, and the interaction of AlCl, AlCl2, AlCl3 with Al4CO4, Al2CO and Al4C3, respectively, thermodynamic analyses were used to study the chloride reaction production of them under the vacuum situation. The stable structures and electronic properties of AlCl, AlCl2 and AlCl3 adsorbed on Al4CO4, Al2CO and Al4C3 were calculated by first-principles calculations by the CASTEP module in the Materials Studio program. The results show that the AlCl3 and AlCl2 molecules have decomposed on the plane of Al4C3 (001), while there are no obvious decomposition of AlCl3 and AlCl2 on Al4CO4 (001) and Al2CO (001) planes. The adsorption of AlCl on the Al4CO4 (001) and Al2CO (001) planes is stronger than that on the Al4C3(001) plane. The interaction strength of AlCl3, as well as AlCl2, with Al4CO4, Al2CO and Al4C3 is in the sequence of Al4CO4Al2CO>Al4C3.

  18. Root Elongation, Root Surface Area and Organic Acid by Rice Seedling Under Al3+ and/or H+ Stress

    Directory of Open Access Journals (Sweden)

    A. E. Azura

    2011-01-01

    Full Text Available Problem statement: Under acidic condition, Al3+ is the most common species in solution. An experiment was conducted to study the effects of Al and/or pH on rice seed germination, root morphology and organic acids release. This study was conducted at ambient temperature in Malaysia. Approach: Two experiments were conducted: (1 Rice seeds undergoing germination were exposed to 0.5 mM CaCl2 solutions containing various concentration of Al (10, 20, 30, 40-50 µM and (2 The seeds were soaked in water taken from an acid sulfate soil area in Malaysia for which the pH was adjusted to a range of values using 0.01 M HCl or NaOH. Results: Root length decreased with increasing Al concentration, while the opposite was true for pH. The trend for the change of root surface area with Al concentration and pH is the same as that of root length. The critical Al concentration for rice growth is 15 µM. This means that rice variety MR 219 grown on 90% of the granary areas in Malaysia is relatively less tolerant compared to other rice varieties. At low pH and high Al concentration, the rice roots secreted citrate and/or oxalate which subsequently formed Alcitrate and Al-oxalate, respectively. This, to a certain extent, had reduced Al toxicity. This is the mechanism of rice tolerance to Al toxicity. Conclusion: Acid sulfate soils in Malaysia allocated for rice production should be limed to increase water pH in the paddy field to 5.0. Then, rice can grow without Al3+ and/or H+ stress.

  19. Synthesis of -Al2O3 nanowires through a boehmite precursor route

    Indian Academy of Sciences (India)

    Qi Yang

    2011-04-01

    Crystalline -Al2O3 nanowires with diameter, 20–40 nm, length above 600 nm and aspect ratio above 30 have been successfully synthesized by thermal decomposition of boehmite (-AlOOH) precursors obtained via hydrothermal route by using AlCl3, NaOH and NH3 as starting materials. Thermogravimetric analysis (TG), differential thermal analysis (DTA), X-ray diffraction (XRD), transmission electron microscope (TEM), selected area electron diffraction (SAED) and high resolution transmission electron microscope (HRTEM) were used to characterize the features of the as-made -Al2O3 nanowires and their -AlOOH precursors. The pH value of the solution and the mixed precipitant play important roles in the formation of -AlOOH nanowires. After calcination at 500°C for 2 h, the orthorhombic -AlOOH transforms to cubic -Al2O3 and retains nanowire morphology.

  20. Phänomenologisch-kritische Destruktion des Aprioriproblems beim frühen Heidegger

    Directory of Open Access Journals (Sweden)

    Radinković Željko

    2012-01-01

    Full Text Available Der Beitrag prüft zunächst, inwiefern beim frühen Heidegger (vor Sein und Zeit eine Verschiebung des Schwerpunktes von dem umweltlichen Charakter der Erlebnisse auf das ‚faktisch‘ daseiende Leben bzw. auf das Phänomen ‚Ich bin‘ zu beobachten ist. Es gilt, den Seinssinn vom ‚Ich bin‘ zu fassen und zwar, indem der Unterschied der Selbsterfahrung zum reflexiv-theoretischen Einstellung bestimmt wird. Diese Bestimmung soll von allen Regions - und Sachgebietsfremdheiten ferngehalten werden. Die Individuation des ‚Ich bin‘ soll nicht als Vereinzelung im Hinblick auf das Allgemeine, sondern als das historische Vereinzelung gefasst werden. Der Seinssinn als Existenzsinn ist in der Eigener­fahrung zu fassen und hat einen Vollzugscharakter. Die Grunderfahrung des Selbst bzw. die Geschichtlichkeit des Vollzuugscharakters des Selbst werden in ein neues grundlegendes Verhältnis zu Apriorität gesetzt. Die zentrale Rolle kommt dabei der Destruktion des historischen Horizontes des Aprioriproblems, worunter eine Radikalisierung der Phänomenologie zu verstehen ist, die versucht, die eigene Geschichtlichkeit bzw. geschichtliche Situation immer ursprünglicher zu vollziehen. Es wird die inhaltliche Struktur des Aprioriproblems geklärt, indem die Geschichte des Aprioriauffassungen nach dem Grad ihrer Daseinsim-manenz bestimmt werden. Die Destruktion des Aprioriproblems wird an den rekonstruktiven Psychologie Paul Natorps und der Kritik der historischen Vernunft Wilhelm Diltheys versucht, wobei diesen die Verdinglichung der Sphäre des Lebendigen vorgeworfen wird.

  1. Comentarios al Salto Social

    Directory of Open Access Journals (Sweden)

    Facultad de Ciencias Económicas

    1995-06-01

    Full Text Available 1. El Plan considera que la política social es un componente central de la estrategia macroeconómica. A diferencia de la administración Gaviria, lo social ha dejado de ser un asunto marginal, es consustancial al desarrollo y, por tanto, se le confiere una dimensión cualitativamente diferente.

  2. Slowenisch als fremdsprache

    Directory of Open Access Journals (Sweden)

    Jože Toporišič

    1981-12-01

    Full Text Available Nicht ganz zwei Millionen Menschen sprechen Slowenisch als Muttersprache. Wenige gibt es, die das Slowenische zwar spre­ chen oder zu sprechen versuchen, aber eine andere Muttersprache haben, vielleicht hunderttausend; für die ist Slowenisch also eine Fremdsprache.

  3. Long term salinity stress in relation to lipid peroxidation, super oxide dismutase activity and proline content of salt-sensitive and salt-tolerant wheat cultivars Estrés salino a largo plazo en relación con peroxidación lipídica, actividad superóxido dismutasa y contenido de prolina de cultivares de trigo sensibles y tolerantes a la salinidad

    Directory of Open Access Journals (Sweden)

    Azam Borzouei

    2012-12-01

    Full Text Available Salinity is a widespread root medium problem limiting productivity of cereal crops worldwide. The ability of plants to tolerate salt is determined by multiple biochemical pathways that facilitate retention and/or acquisition of water, protect chloroplast functions, and maintain ion homeostasis. Therefore, the ability of salt-sensitive ('Tajan' and salt-tolerant cultivar ('Bam' of Triticum aestivum L. to adapt to a saline environment were evaluated in a set of greenhouse experiments under salt stress during three growth stages (tillering, 50% anthesis, and 10 d after anthesis. Plants were irrigated by different saline waters with electrical conductivities of 1.3, 6, 8, 10, and 12 dS m-1, which were obtained by adding NaCl:CaCl2 in 10:1 molar ratio to fresh water. Differences in growth parameters, lipid peroxidation, superoxide dismutase (SOD activity, and proline accumulation were tested in order to put forward the relative tolerance or sensitivity of cultivars. Results indicated that both parameters differ according to the cultivar's ability in coping oxidative stress caused by salinity. We observed a greater decline in the growth parameters and grain yield under salt stress in 'Tajan' than in 'Bam'. Malondialdehyde content was also higher in 'Tajan'. The improved performance of the 'Bam' under high salinity was accompanied by an increase in SOD (EC 1.15.1.1 activity and proline content at all growth stages. Growth parameters, lipid peroxidation and proline accumulation results are also in good correlation with supporting this cultivar is being relatively tolerant.La salinidad es un problema del medio radical ampliamente distribuido que limita la productividad de los cultivos de cereal en todo el mundo. La capacidad de las plantas para tolerar la sal está determinada por multiples vías bioquímicas que facilitan la retención y/o adquisición de agua, protegen las funciones del cloroplasto, y mantienen la homeostasis iónica. Por lo tanto, se

  4. Effects of pH on the electrochemical behaviour of titanium alloys for implant applications.

    Science.gov (United States)

    Souza, Maria E P; Lima, Lonetá; Lima, Carmo R P; Zavaglia, Cecília A C; Freire, Célia M A

    2009-02-01

    The electrochemical behaviour of two commercial titanium alloys Ti-6Al-4 V (ASTM F136) and Ti-13Nb-13Zr (ASTM F1713) was investigated in Ringer physiological solution at two pH values (5.5 and 7.0). The corrosion properties were examined by using electrochemical techniques: Potentiodynamic anodic polarization, cyclic polarization and electrochemical impedance spectroscopy (EIS). The electrochemical corrosion properties of both alloys at different conditions were measured in terms of corrosion potential (E (corr)), corrosion current density (i (corr)) and passivation current density (i (pass)). Equivalent electrical circuits were used to modulate EIS data, in order to characterize alloys surface and better understanding the pH effect on the interface alloy/solution.

  5. Characterization of Anodic Aluminum Oxide Membrane with Variation of Crystallizing Temperature for pH Sensor.

    Science.gov (United States)

    Yeo, Jin-Ho; Lee, Sung-Gap; Jo, Ye-Won; Jung, Hye-Rin

    2015-11-01

    We fabricated electrolyte-dielectric-metal (EDM) device incorporating a high-k Al2O3 sensing membrane from a porous anodic aluminum oxide (AAO) using a two step anodizing process for pH sensors. In order to change the properties of the AAO template, the crystallizing temperature was varied from 400 degrees C to 700 degrees C over 2 hours. The structural properties were observed by field emission scanning electron microscopy (FE-SEM). The pH sensitivity increased with an increase in the crystallizing temperature from 400 degrees C to 600 degrees C. However at 700 degrees C, deformation occurred. The porous AAO sensor with a crystallizing temperature of 600 degrees C displayed the good sensitivity and long-term stability and the values were 55.7 mV/pH and 0.16 mV/h, respectively. PMID:26726567

  6. Indicator paper made of natural excerpts: an alternative based on laboratory experiences for learning of the ph concept

    OpenAIRE

    Casas Mateus, Jaime Augusto; Castillo Daza, Herbert Javier; Noy Hilarión, Juan Manuel; Palomares Parada, Adriana Natalia; Rodríguez Valbuena, Rubi Liliana

    2009-01-01

    El siguiente artículo se encuentra enmarcado en experiencias de laboratorio que se orientan desde diagramas de flujo muy sintéticos e ilustrativos, que promueven un acercamiento al concepto estructurante de pH, y su relación con el comportamiento ácido-base y las soluciones buffer. Para la enseñanza de dichos conceptos, se efectuó la elaboración y estandarización de tres tipos de papel indicador de pH, utilizando sustancias naturales, tales como la col lombarda, los pétalos de ...

  7. Dissolution kinetics of a lunar glass simulant at 25 degrees C: the effect of pH and organic acids

    Science.gov (United States)

    Eick, M. J.; Grossl, P. R.; Golden, D. C.; Sparks, D. L.; Ming, D. W.

    1996-01-01

    The dissolution kinetics of a simulated lunar glass were examined at pH 3, 5, and 7. Additionally, the pH 7 experiments were conducted in the presence of citric and oxalic acid at concentrations of 2 and 20 mM. The organic acids were buffered at pH 7 to examine the effect of each molecule in their dissociated form. At pH 3, 5, and 7, the dissolution of the synthetic lunar glass was observed to proceed via a two-stage process. The first stage involved the parabolic release of Ca, Mg, Al, and Fe, and the linear release of Si. Dissolution was incongruent, creating a leached layer rich in Si and Ti which was verified by transmission electron microscopy (TEM). During the second stage the release of Ca, Mg, Al, and Fe was linear. A coupled diffusion/surface dissolution model was proposed for dissolution of the simulated lunar glass at pH 3, 5, and 7. During the first stage the initial release of mobile cations (i.e., Ca, Mg, Al, Fe) was limited by diffusion through the surface leached layer of the glass (parabolic release), while Si release was controlled by the hydrolysis of the Si-O-Al bonds at the glass surface (linear release). As dissolution continued, the mobile cations diffused from greater depths within the glass surface. A steady-state was then reached where the diffusion rate across the increased path lengths equalled the Si release rate from the surface. In the presence of the organic acids, the dissolution of the synthetic lunar glass proceeded by a one stage process. The release of Ca, Mg, Al, and Fe followed a parabolic relationship, while the release of Si was linear. The relative reactivity of the organic acids used in the experiments was citrate > oxalate. A thinner leached layer rich in Si/Ti, as compared to the pH experiments, was observed using TEM. Rate data suggest that the chemisorption of the organic anion to the surface silanol groups was responsible for enhanced dissolution in the presence of the organic acids. It is proposed that the increased

  8. Efecto de las cargas articulares sobre el flujo y pH salival Effect of TMJ loading on salivary flow and pH

    Directory of Open Access Journals (Sweden)

    RJ Castro

    2011-04-01

    Full Text Available Una alteración del flujo salival es clave en el desarrollo de caries, enfermedad periodontal e infecciones oportunistas. El flujo salival está determinado por diversos estímulos que actúan sobre receptores de distinta naturaleza, entre ellos mecanoreceptores articulares. Algunos estudios demuestran que las cargas articulares actúan sobre estos receptores, modificando cualitativa y cuantitativamente la secreción salival. El objetivo de este estudio fue determinar si existe una relación entre la aplicación controlada de cargas articulares y cambios en el flujo y pH salival. 30 voluntarios fueron seleccionados según criterios de inclusión establecidos. Se elaboró un dispositivo interoclusal que en relación a piezas 1.5 y 2.5, tenía botones acrílicos de 1 mm de espesor, los que al ejercer fuerzas sobre ellos provocan cargas reversibles sobre la ATM. Antes de usar el dispositivo, en cada individuo se midió flujo salival no estimulado (FSNE el flujo salival estimulado (FSE y el pH de ambos. Tras un periodo de adaptación diaria por una semana, cada participante usó el dispositivo durante 1 hora, ejerciendo fuerza masticatoria sostenida. Luego se midieron ambos flujos y el pH correspondiente. El procedimiento fue repetido por 7 días, bajo supervisión. No se observó una relación aparente entre la aplicación controlada de cargas articulares y cambios volumétricos de flujo salival. Las mujeres tuvieron un FSE y FSNE menor al de los hombres. La aplicación de sobrecargas articulares por un breve período de tiempo provoca una caída del pH del FSE luego de 3 días de aplicación.Altered salivary flow is key for the onset of dental caries, periodontal disease and opportunistic infections. Salivary flow is determined by various stimuli on several receptors, including joint mechanoreceptors. Some studies show that loads on the TMJ affect these receptors causing changes on the quality and quantity of saliva secretion. The aim of this

  9. Characterzation and separation of Al13 species using gel-filtration chromatography

    Institute of Scientific and Technical Information of China (English)

    CHU; Yongbao; GAO; Baoyu; YUE; Qinyan; WANG; Yan

    2006-01-01

    A polyaluminum chloride (PAC) sample was prepared using a slow alkaline titration method. The Bio-Gel P-100 gel column chromatographic technique was used to separate and characterize the various forms of aluminum present in the prepared PAC solution. The effluents from a gel column were monitored using online chemical method: Al-Ferron timed complexation spectrophotometry and by 27Al nuclear magnetic resonance (NMR) spectroscopy. Effects of different experimental conditions such as eluent flow rate, ionic strength and pH on separation of Al13 were investigated. Experimental results indicated that molecule size exclusion was not the only parameter affecting the column chromatographic separation efficiency of Al13 but molecule charge as well. Reducing the eluent flow rate, increasing the ionic strength and suitable pH resulted in increase in the separation efficiency. Experimental results clearly indicated that by varying the experimental conditions, it is possible to produce pure Al13 species using a gel column chromatographic technique.

  10. Electrochemical oxidation of 4-chloro phenol over a carbon paste electrode modified with Zn Al layered double hydroxides

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez F, D.; Palomar P, M.; Licona S, T. de J.; Romero R, M. [Universidad Autonoma Metropolitana, Unidad Azcapotzalco, Departamento de Materiales, Av. San Pablo 180, Col. Reynosa-Tamaulipas, 02200 Mexico D. F. (Mexico); Valente, Jaime S., E-mail: mepp@correo.azc.uam.mx [Instituto Mexicano del Petroleo, Eje Central No. 152, 07730 Mexico D. F. (Mexico)

    2014-07-01

    A study is presented on the electrochemical oxidation of 4-chloro phenol (4cp) in aqueous solution using a bare carbon paste electrode, Cpe, and another one that was modified with Zn Al layered double hydroxides (Cpe/Zn Al-LDH). The electro-oxidation was effected at ph values ranging from 3 up to 11. It was found through cyclic voltammetry that this process was irreversible, namely, there were no reduction peaks, and that depending on the nature of the electrode, the anodic current was limited either by adsorption (Cpe) or diffusion (Cpe/Zn Al-LDH). The energy required and the oxidation reaction rate depended on the ph and on the nature of the electrode, such that the greater rates were obtained when the Cpe/Zn Al-LDH electrode and acid ph were used. The Zn Al-LDH was characterized by means of X-ray diffraction. (Author)

  11. In vitro synthesis and purification of PhIP-deoxyguanosine and PhIP-DNA oligomer covalent complexes

    Energy Technology Data Exchange (ETDEWEB)

    Freeman, J.

    1994-12-01

    2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a heterocyclic amine compound formed when meats are cooked at high temperatures. PhIP damages DNA by forming covalent complexes with DNA carcinogen. In an effort to understand how the binding of PhIP to DNA may cause cancer, it is important to characterize the structures of PhIP-damaged DNA molecules. Our HPLC data support fluorescence and {sup 32}P Post-labeling studies which indicate the formation of several species of 2{prime}deoxyguanosine-(dG) or oligodeoxynucleotide-PhIP adducts. The reaction of PhIP with dG resulted in a reddish precipitate that was likely the major adduct, N-(deoxyguanosin-8-yl)-PhIP (dG-C8-PhIP) adduct, with a more polar adduct fraction remaining in the supernatant. Reversed-phase HPLC analysis of the adducts in the supernatant revealed the existence of species of much shorter retention times than the dG-C8-PhIP adduct, confirming that these species are more polar than dG-C8-PhIP. At least four adducts were formed in the reaction of PhIP with DNA oligomer. HPLC analysis of the PhIP-DNA oligomer supernatant after butanol extractions revealed four unresolved peaks which spectra had maximum wavelengths between 340 and 360 nm. Though adduct peaks were not completely resolved, there was {approximately}3 minutes interval between the DNA oligomer peak and the adduct peaks. Furthermore, fluorescence emission data of the DNA oligomer-PhIP adduct solution show heterogeneous binding. The more polar PhIP adducts were fraction-collected and their structures will be solved by nuclear magnetic resonance or x-ray crystallography.

  12. Microscopic monitoring of extracellular pH in dental biofilms

    DEFF Research Database (Denmark)

    Schlafer, Sebastian; Garcia, Javier; Greve, Matilde;

    pH in dental biofilm is a key virulence factor for the development of caries lesions. The complex three-dimensional architecture of dental biofilms leads to steep gradients of nutrients and metabolites, including organic acids, across the biofilm. For decades, measuring pH in dental biofilm has......H ratiometry, can be employed to map the pH landscape in dental biofilm with more detail. However, when pH sensitive fluorescent probes are used to visualize pH in biofilms, it is crucial to differentiate between extracellular and intracellular pH. Intracellular microbial pH and pH in the extracellular matrix...... differ considerably, and only extracellular pH in dental biofilms affects the underlying tooth. We here developed a method to reliably monitor extracellular pH in dental biofilm microscopically with the ratiometric pH-sensitive dye C-SNARF-4. Fluorescent emissions of CSNARF- 4 can be used to calculate...

  13. Osmolytes contribute to pH homeostasis of Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Ryan D Kitko

    Full Text Available BACKGROUND: Cytoplasmic pH homeostasis in Escherichia coli includes numerous mechanisms involving pH-dependent catabolism and ion fluxes. An important contributor is transmembrane K+ flux, but the actual basis of K+ compensation for pH stress remains unclear. Osmoprotection could mediate the pH protection afforded by K+ and other osmolytes. METHODS AND PRINCIPAL FINDINGS: The cytoplasmic pH of E. coli K-12 strains was measured by GFPmut3 fluorimetry. The wild-type strain Frag1 was exposed to rapid external acidification by HCl addition. Recovery of cytoplasmic pH was enhanced equally by supplementation with NaCl, KCl, proline, or sucrose. A triple mutant strain TK2420 defective for the Kdp, Trk and Kup K+ uptake systems requires exogenous K+ for steady-state pH homeostasis and for recovery from sudden acid shift. The K+ requirement however was partly compensated by supplementation with NaCl, choline chloride, proline, or sucrose. Thus, the K+ requirement was mediated in part by osmolarity, possibly by relieving osmotic stress which interacts with pH stress. The rapid addition of KCl to strain TK2420 suspended at external pH 5.6 caused a transient decrease in cytoplasmic pH, followed by slow recovery to an elevated steady-state pH. In the presence of 150 mM KCl, however, rapid addition of another 150 mM KCl caused a transient increase in cytoplasmic pH. These transient effects may arise from secondary K+ fluxes occurring through other transport processes in the TK2420 strain. CONCLUSIONS: Diverse osmolytes including NaCl, KCl, proline, or sucrose contribute to cytoplasmic pH homeostasis in E. coli, and increase the recovery from rapid acid shift. Osmolytes other than K+ restore partial pH homeostasis in a strain deleted for K+ transport.

  14. ALS insertion devices

    International Nuclear Information System (INIS)

    The Advanced Light Source (ALS), the first US third generation synchrotron radiation source, is currently under construction at the Lawrence Berkeley Laboratory. The low-emittance, 1.5 GeV electron storage ring and the insertion devices are specifically designed to produce high brightness beams in the UV to soft X-Ray range. The planned initial complement of insertion devices includes four 4.6 m long undulators, with period lengths of 3.9 cm, 5.0 cm (2) and 8.0 cm, and a 2.9 m long wiggler of 16 cm period length. Undulator design is well advanced and fabrication has begun on the 5.0 cm and 8.0 cm period length undulators. This paper discusses ALS insertion device requirements; general design philosophy; and design of the magnetic structure, support structure/drive systems, control system and vacuum system. 18 refs., 9 figs., 5 tabs

  15. De GPS al mapa

    Directory of Open Access Journals (Sweden)

    Esteban Dörries

    2016-03-01

    Full Text Available Las coordenadas Lambert obtenidas a partir de mediciones con equipos GPS de mano, llamados a veces navegadores, en ciertos casos confunden al usuario, por diferir claramente de su posición real al ser graficadas en un mapa del Instituto Geográfico Nacional (IGN: Esto puede resolverse con suficiente exactitud mediante una transformación de Molodensky, seguida de la correspondiente proyección cartográfica. Sin embargo, los tres parámetros necesarios para la transformación, supuestamente válidos para Costa Rica, se encuentran en muchas variantes y producen obviamente resultados diferentes. En este trabajo se analizan los fundamentos del problema y sus posibles soluciones, culminando con un estudio comparativo de ocho casos, que permite seleccionar los valores más adecuados para los parámetros.

  16. Studien zur Phänomenologie und Normativität der Liebe

    OpenAIRE

    Pereira Restrepo, Sebastián

    2014-01-01

    Die Texte der vorliegenden Arbeit sind Stationen auf dem Weg zu einer normativen Theorie der romantischen Liebe. Was hier unter einer normativen Theorie der romantischen Liebe verstanden wird, gründet auf folgenden Annahmen über das Liebesphänomen und lässt sich in Bezug auf sie kurz zusammenfassen: das Phänomen der romantischen Liebe – sowie das Liebesphänomen als Ganzes – bildet ein Kontinuum. An dem einen Ende dieses Spektrums gibt es gute, an dem anderen Ende schlechte Ausprägungen der Li...

  17. AL-IZDIWAJIYYAH AL-LUGHOWIYAH FII ISTIHDHAMI AL-LUGHOH AL-‘ARABIYAH

    OpenAIRE

    Imam Muslimin

    2011-01-01

    Al-Izdiwajiyyah (diglosia) is standardizing a specific language when there are two variants of language that live side by side in societal life and each variant has its own social function. Disglosia is related to the use of local languages variations of low language and high language in a community. In Arabic language, disglosia covers dialects among the speakers, for instance there are two variants of language that each has roles and functions. The use of the variant depends on the situatio...

  18. Carta al editor

    Directory of Open Access Journals (Sweden)

    Harry Pachajoa

    2012-02-01

    Full Text Available Recently, Valencia et al., published a very interesting article called «Lipid profile in a group of patients with Turner’s syndrome at Clínica Universitaria Bolivariana in the city of Medellín between 2000 and 2009". An article which evaluated lipid levels in patients withTurner syndrome in a Colombian clinic, the study associated results of lipid profile with karyotype and other risk factors for coronary heart disease.

  19. Carta al editor

    OpenAIRE

    Harry Pachajoa

    2012-01-01

    Recently, Valencia et al., published a very interesting article called «Lipid profile in a group of patients with Turner’s syndrome at Clínica Universitaria Bolivariana in the city of Medellín between 2000 and 2009". An article which evaluated lipid levels in patients withTurner syndrome in a Colombian clinic, the study associated results of lipid profile with karyotype and other risk factors for coronary heart disease.

  20. Equilibrios ácido-base. Cálculo del pH de mezclas de protolitos (carbonato, hidrogenocarbonato y HCl). Ejercicio interactivo.

    OpenAIRE

    Milla González, Miguel

    2015-01-01

    Se propone calcular el pH de una disolución constituida por la mezcla de 100 mL de carbonato de sodio, 100 mL de hidrogenocarbonato de sodio y 50 mL de ácido clorhídrico de molaridades diferentes. Mediante una simulación de las reacciones que tienen lugar, se averigua la composición de la disolución al conseguir el equilibrio. A partir de aquí, se aplica la expresión del pH de un anfolito para llevar a cabo el cálculo del pH buscado.

  1. Continuous fetal tissue pH measurement in labor.

    Science.gov (United States)

    Young, B K; Noumoff, J; Klein, S A; Katz, M

    1978-11-01

    Fifty-one women in labor had continuous monitoring of fetal scalp tissue pH, fetal heart rate by ECG, and uterine contractions. A miniature pH electrode secured by a double spiral fetal ECG electrode was used for measurement of fetal pH every 15 seconds. The results were correlated with fetal scalp blood pH values obtained simultaneously. Fetal scalp sampling is intermittent, requires repeated scalp incisions, is subject to errors due to air mixing and coagulation of the blood sample, and is uncomfortable for the parturient. Placement of the tissue pH electrode allows continuous data recording with the minimum discomfort to the patient and the least number of fetal scalp incisions. Clinical use of the tissue pH electrode might be a practical alternative to fetal scalp samples, if the data obtained accurately reflect fetal status.

  2. Cell wall pH and auxin transport velocity

    Science.gov (United States)

    Hasenstein, K. H.; Rayle, D.

    1984-01-01

    According to the chemiosmotic polar diffusion hypothesis, auxin pulse velocity and basal secretion should increase with decreasing cell wall pH. Experiments were designed to test this prediction. Avena coleoptile sections were preincubated in either fusicoccin (FC), cycloheximide, pH 4.0, or pH 8.0 buffer and subsequently their polar transport capacities were determined. Relative to controls, FC enhanced auxin (IAA) uptake while CHI and pH 8.0 buffer reduced IAA uptake. Nevertheless, FC reduced IAA pulse velocity while cycloheximide increased velocity. Additional experiments showed that delivery of auxin to receivers is enhanced by increased receiver pH. This phenomenon was overcome by a pretreatment of the tissue with IAA. Our data suggest that while acidic wall pH values facilitate cellular IAA uptake, they do not enhance pulse velocity or basal secretion. These findings are inconsistent with the chemiosmotic hypothesis for auxin transport.

  3. Computer model of unstirred layer and intracellular pH changes. Determinants of unstirred layer pH.

    Science.gov (United States)

    Marrannes, Roger

    2013-06-01

    Transmembrane acid-base fluxes affect the intracellular pH and unstirred layer pH around a superfused biological preparation. In this paper the factors influencing the unstirred layer pH and its gradient are studied. An analytical expression of the unstirred layer pH gradient in steady state is derived as a function of simultaneous transmembrane fluxes of (weak) acids and bases with the dehydration reaction of carbonic acid in equilibrium. Also a multicompartment computer model is described consisting of the extracellular bulk compartment, different unstirred layer compartments and the intracellular compartment. With this model also transient changes and the influence of carbonic anhydrase (CA) can be studied. The analytical expression and simulations with the multicompartment model demonstrate that in steady state the unstirred layer pH and its gradient are influenced by the size and type of transmembrane flux of acids and bases, their dissociation constant and diffusion coefficient, the concentration, diffusion coefficient and type of mobile buffers and the activity and location of CA. Similar principles contribute to the amplitude of the unstirred layer pH transients. According to these models an immobile buffer does not influence the steady-state pH, but reduces the amplitude of pH transients especially when these are fast. The unstirred layer pH provides useful information about transmembrane acid-base fluxes. This paper gives more insight how the unstirred layer pH and its transients can be interpreted. Methodological issues are discussed. PMID:23860924

  4. Computer model of unstirred layer and intracellular pH changes. Determinants of unstirred layer pH.

    Science.gov (United States)

    Marrannes, Roger

    2013-06-01

    Transmembrane acid-base fluxes affect the intracellular pH and unstirred layer pH around a superfused biological preparation. In this paper the factors influencing the unstirred layer pH and its gradient are studied. An analytical expression of the unstirred layer pH gradient in steady state is derived as a function of simultaneous transmembrane fluxes of (weak) acids and bases with the dehydration reaction of carbonic acid in equilibrium. Also a multicompartment computer model is described consisting of the extracellular bulk compartment, different unstirred layer compartments and the intracellular compartment. With this model also transient changes and the influence of carbonic anhydrase (CA) can be studied. The analytical expression and simulations with the multicompartment model demonstrate that in steady state the unstirred layer pH and its gradient are influenced by the size and type of transmembrane flux of acids and bases, their dissociation constant and diffusion coefficient, the concentration, diffusion coefficient and type of mobile buffers and the activity and location of CA. Similar principles contribute to the amplitude of the unstirred layer pH transients. According to these models an immobile buffer does not influence the steady-state pH, but reduces the amplitude of pH transients especially when these are fast. The unstirred layer pH provides useful information about transmembrane acid-base fluxes. This paper gives more insight how the unstirred layer pH and its transients can be interpreted. Methodological issues are discussed.

  5. Aluminium (Al) fractionation and speciation; getting closer to describing the factors influencing Al(3+) in water impacted by acid mine drainage.

    Science.gov (United States)

    Chamier, Jessica; Wicht, Merrill; Cyster, Lilburne; Ndindi, Nosintu P

    2015-07-01

    Acid mine drainage (AMD) severely impacts the water chemistry of a receiving resource, changing the occurrence, speciation and toxicity of metals such as Aluminium (Al). The toxicity of Al is determined by its speciation represented by the labile monomer Al fraction or Al(3+). The purpose of the study was to combine fractionation and Visual MINTEQ speciation to calculate the effect of AMD altered water chemistry on Al speciation and Al(3+) concentration. Water in rivers impacted by AMD presented with monomeric Al (Almon) concentrations between 0.35 and 15.37mgL(-)(1) which existed almost exclusively in the toxic labile form (98%). For the reference site, Almon was less than 2% (10μgL(-1)), suggesting significantly lower Al toxicity. Principal component analysis plots illustrated that labile Al was directly related to the total Al and iron concentrations and strongly influenced by parameters such as pH, electrical conductivity, sulphate and dissolved organic carbon. Visual MINTEQ modelling was used to determine the primary Al species distribution. The dominant form of Al in AMD impacted water was AlSO4(+), which increased proportionally with the sulphate and Al(3+) concentration. Heavily impacted areas, presented with an average of 1mgmL(-)(1) Al(3+), which poses a potential human health risk. A novel centrifugal ultrafiltration method was investigated as an alternative to determining Almon to simplify the speciation of Al. Monomeric and centrifugal ultrafiltrated (<10kD) Al fractions were significantly similar (p=0.74), suggesting that ultrafiltration may present a time, energy and cost saving alternative to organic extraction of Almon.

  6. Aluminium (Al) fractionation and speciation; getting closer to describing the factors influencing Al(3+) in water impacted by acid mine drainage.

    Science.gov (United States)

    Chamier, Jessica; Wicht, Merrill; Cyster, Lilburne; Ndindi, Nosintu P

    2015-07-01

    Acid mine drainage (AMD) severely impacts the water chemistry of a receiving resource, changing the occurrence, speciation and toxicity of metals such as Aluminium (Al). The toxicity of Al is determined by its speciation represented by the labile monomer Al fraction or Al(3+). The purpose of the study was to combine fractionation and Visual MINTEQ speciation to calculate the effect of AMD altered water chemistry on Al speciation and Al(3+) concentration. Water in rivers impacted by AMD presented with monomeric Al (Almon) concentrations between 0.35 and 15.37mgL(-)(1) which existed almost exclusively in the toxic labile form (98%). For the reference site, Almon was less than 2% (10μgL(-1)), suggesting significantly lower Al toxicity. Principal component analysis plots illustrated that labile Al was directly related to the total Al and iron concentrations and strongly influenced by parameters such as pH, electrical conductivity, sulphate and dissolved organic carbon. Visual MINTEQ modelling was used to determine the primary Al species distribution. The dominant form of Al in AMD impacted water was AlSO4(+), which increased proportionally with the sulphate and Al(3+) concentration. Heavily impacted areas, presented with an average of 1mgmL(-)(1) Al(3+), which poses a potential human health risk. A novel centrifugal ultrafiltration method was investigated as an alternative to determining Almon to simplify the speciation of Al. Monomeric and centrifugal ultrafiltrated (<10kD) Al fractions were significantly similar (p=0.74), suggesting that ultrafiltration may present a time, energy and cost saving alternative to organic extraction of Almon. PMID:25747302

  7. Ratiometric Imaging of Extracellular pH in Dental Biofilms.

    Science.gov (United States)

    Schlafer, Sebastian; Dige, Irene

    2016-03-09

    The pH in bacterial biofilms on teeth is of central importance for dental caries, a disease with a high worldwide prevalence. Nutrients and metabolites are not distributed evenly in dental biofilms. A complex interplay of sorption to and reaction with organic matter in the biofilm reduces the diffusion paths of solutes and creates steep gradients of reactive molecules, including organic acids, across the biofilm. Quantitative fluorescent microscopic methods, such as fluorescence life time imaging or pH ratiometry, can be employed to visualize pH in different microenvironments of dental biofilms. pH ratiometry exploits a pH-dependent shift in the fluorescent emission of pH-sensitive dyes. Calculation of the emission ratio at two different wavelengths allows determining local pH in microscopic images, irrespective of the concentration of the dye. Contrary to microelectrodes the technique allows monitoring both vertical and horizontal pH gradients in real-time without mechanically disturbing the biofilm. However, care must be taken to differentiate accurately between extra- and intracellular compartments of the biofilm. Here, the ratiometric dye, seminaphthorhodafluor-4F 5-(and-6) carboxylic acid (C-SNARF-4) is employed to monitor extracellular pH in in vivo grown dental biofilms of unknown species composition. Upon exposure to glucose the dye is up-concentrated inside all bacterial cells in the biofilms; it is thus used both as a universal bacterial stain and as a marker of extracellular pH. After confocal microscopic image acquisition, the bacterial biomass is removed from all pictures using digital image analysis software, which permits to exclusively calculate extracellular pH. pH ratiometry with the ratiometric dye is well-suited to study extracellular pH in thin biofilms of up to 75 µm thickness, but is limited to the pH range between 4.5 and 7.0.

  8. Methotrexate intercalated ZnAl-layered double hydroxide

    International Nuclear Information System (INIS)

    The anticancerous drug methotrexate (MTX) has been intercalated into an ZnAl-layered double hydroxide (LDH) using an anion exchange technique to produce LDH-MTX hybrids having particle sizes in the range of 100-300 nm. X-ray diffraction studies revealed increases in the basal spacings of ZnAl-LDH-MTX hybrid on MTX intercalation. This was corroborated by the transmission electron micrographs, which showed an increase in average interlayer spacing from 8.9 A in pristine LDH to 21.3 A in LDH-MTX hybrid. Thermogravimetric analyses showed an increase in the decomposition temperature for the MTX molecule in the LDH-MTX hybrid indicating enhanced thermal stability of the drug molecule in the LDH nanovehicle. The cumulative release profile of MTX from ZnAl-LDH-MTX hybrids in phosphate buffer saline (PBS) at pH 7.4 was successfully sustained for 48 h following Rigter-Peppas model release kinetics via diffusion. - Graphical abstract: ZnAl-layered double hydroxide intercalated with methotrexate (∼34% loading) promises the possibility of use of ZnAl-LDH material as drug carrier and in controlled delivery. Highlights: → ZnAl-layered double hydroxide methotrexate nanohybrid has been synthesized. → XRD and TEM studies on nanohybrid revealed successful intercalation of methotrexate. → TG and CHN analyses showed ∼34 wt% of methotrexate loading into the nanohybrid. → Possibility of use of ZnAl-LDH material as drug carrier and in delivery.

  9. Growth and production of castor bean under different levels of irrigation water salinity and nitrogen dosesCrescimento e produção da mamoneira cultivada sob diferentes níveis de salinidade da água de irrigação e doses de nitrogênio

    Directory of Open Access Journals (Sweden)

    Reginaldo Gomes Nobre

    2013-06-01

    mamoneira cv. BRS Energia. O experimento foi conduzido em lisímetros sob condições de campo, no Centro de Ciências e Tecnologia Agroalimentar da Universidade Federal de Campina Grande. Adotou-se o delineamento em blocos inteiramente casualizados em esquema fatorial 5 x 5, com três repetições. Os tratamentos consistiram da combinação de cinco níveis de condutividade elétrica da água de irrigação (0,4; 1,4; 2,4; 3,4 e 4,4 dS m-1 e cinco doses de nitrogênio (50; 75; 100; 125 e 150% da dose recomendada. O número de folhas, o diâmetro caulinar, a altura de planta, a fitomassa seca do caule e de folhas, e o número de frutos no racemo primário da mamoneira cv. BRS Energia foram afetados linear e negativamente pela salinidade da água a partir de 0,4 dS m-1; a fitomassa seca de folhas e a produção do racemo primário são as variáveis mais sensíveis ao estresse salino; doses crescentes de adubação nitrogenada promoveram, na colheita, aumento na fitomassa seca de caule e de folhas e no número de frutos no racemo primário; a aplicação de doses crescentes de nitrogênio reduziu o efeito da salinidade sobre o diâmetro de caule da mamoneira cv. BRS Energia.

  10. PAMETNE TEKSTILIJE Z INTEGRIRANIMI BARVNIMI pH SENZORJI

    OpenAIRE

    Lakić, Marijana

    2010-01-01

    Tekstilije, ki spremenijo svojo barvo v odvisnosti od pH sistema ali medija v katerem se nahajajo, se lahko uporabljajo kot senzorji za pH okolja, saj spremembo barve lahko zaznamo s prostim očesom. Z namenom izdelave takšne pametne tekstilije smo inkorporirali pH indikatorja BCG in BTB v sol-gel membrane, ter le te nanesli na aktivirani celulozni substrat — bombaž in viskozo. Po izpostavitvi različnim pH, smo odzivnost sol-gel nanosov določali barvnometrično ter s pomočjo merjenja odzivn...

  11. Nanosensor aided photoacoustic measurement of pH in vivo

    Science.gov (United States)

    Ray, Aniruddha; Yoon, Hyung Ki; Kopelman, Raoul; Wang, Xueding

    2013-03-01

    pH plays a critical role in many aspects of cell and tissues physiology. Lower pH is also a typical characteristic of arthritic joints and tumor tissues. These pH anomalies are also exploited in different drug delivery mechanisms. Here we present, a new method of pH sensing in vivo using spectroscopic photoacoustic measurements facilitated by pH sensitive nanosensors. The nanosensors consist of Seminaphtharhodafluor (SNARF), a pH sensitive dye, encapsulated in a specially designed polyacrylamide hydrogel matrix with a hydrophobic core. The photoacoustic intensity ratio between the excitation wavelengths of 585nm and 565nm increases in the pH range from 6.0 to 8.0 and is used to determine the pH of the local environment. These nanosensors are biodegradable, biocompatible, have a long plasma lifetime and can be targeted to any type of cells or tissues by surface modification using proper targeting moieties. The encapsulation of the dye prevents the interaction of the dye with proteins in plasma and also reduces the dye degradation. The SNARF dye in its free form loses 90% of its absorbance in presence of albumin, a protein found in abundance in plasma, and this has severely limited its adaptation to in vivo environments. In comparison, the SNARF nanosensors lose only 16% of their absorbance in the same environment. We employ these nanosensors to demonstrate the feasibility of pH sensing in vivo through photoacoustic measurements on a rat joint model.

  12. pH jump induced α-helix folding.

    Directory of Open Access Journals (Sweden)

    Donten M. L.

    2013-03-01

    Full Text Available pH can be used to impact the folding equilibrium of peptides and proteins. This fact is utilized, similarly to temperature jumps, in pH jump experiments employing laser time-resolved spectroscopy to study the function and structural dynamics of these molecules. Here the application of pH jumps in folding experiments was investigated. Experiments with poly-L-glutamic acid alpha-helix formation shown the critical aspects of pH jump experiments and yielded direct information about the folding kinetics monitored with the amide I IR band.

  13. ELECTROLYSIS OF SWINE MANURE EFFLUENTS USING THREE DIFFERENT ELECTRODES Fe-Fe, Al-Al AND Fe-Al

    Directory of Open Access Journals (Sweden)

    S. Rahman

    2014-01-01

    Full Text Available Swine effluent with high organic strength need to be treated to make it suitable for applying to crop/pasture fields, or discharging to any waterways. Electrocoagulation is a relatively simpler and cheaper technique over biological and chemical treatment methods currently used to treat high-strength industrial and municipal wastewater. The performance of an electrocoagulation system mainly depends on the pH, Electrical Conductivity (EC of the medium, Chemical Oxygen Demand (COD loading rates and catalytic activity of the electrodes used. In this research, a study was conducted to compare the pollutant removal efficiencies of three electrodes (Fe-Fe, Al-Al and Fe-Al with three electric current levels (500, 1000 and 2000 mA while treating swine manure effluents. The electrochemical cell consisted of two parallel rectangular plates (90×25×1.5 mm of Iron (Fe-Fe, Aluminum (Al-Al and Iron-Aluminum (Fe-Al, later on described as hybrid electrodes; immersed in a beaker with 550 mL swine effluents and powered by a Direct Current (DC supply. All studies were conducted in batches at room temperature. In general, removal efficiencies were increased with increasing current densities and electrolysis times for electrodes evaluated. Aluminum electrodes outperformed iron and hybrid (iron-aluminum electrodes in removing Total Phosphorus (TP at all current density levels tested. Overall, use of hybrid electrodes resulted in better COD removal. For the same treatment times (1200 s at higher current density (21 mA cm-2, hybrid electrodes removed about 100% COD, which are about 1.9 and 1.3 times higher than those of aluminum and iron electrodes, respectively. Iron electrodes showed the highest removal efficiency (85% for Total Organic Carbon (TOC at 21 mA cm-2 current density and 1200 s treatment time. Overall, lower Specific Electrical Energy Consumptions (SEECs per kg of Pollutants (TP, COD and TOC were estimated for the aluminum

  14. pH induced contrast in viscoelasticity imaging of biopolymers

    Science.gov (United States)

    Yapp, R D; Insana, M F

    2009-01-01

    Understanding contrast mechanisms and identifying discriminating features is at the heart of diagnostic imaging development. This report focuses on how pH influences the viscoelastic properties of biopolymers to better understand the effects of extracellular pH on breast tumour elasticity imaging. Extracellular pH is known to decrease as much as 1 pH unit in breast tumours, thus creating a dangerous environment that increases cellular mutatation rates and therapeutic resistance. We used a gelatin hydrogel phantom to isolate the effects of pH on a polymer network with similarities to the extracellular matrix in breast stroma. Using compressive unconfined creep and stress relaxation measurements, we systematically measured the viscoelastic features sensitive to pH by way of time domain models and complex modulus analysis. These results are used to determine the sensitivity of quasi-static ultrasonic elasticity imaging to pH. We found a strong elastic response of the polymer network to pH, such that the matrix stiffness decreases as pH was reduced, however the viscous response of the medium to pH was negligible. While physiological features of breast stroma such as proteoglycans and vascular networks are not included in our hydrogel model, observations in this study provide insight into viscoelastic features specific to pH changes in the collagenous stromal network. These observations suggest that the large contrast common in breast tumours with desmoplasia may be reduced under acidic conditions, and that viscoelastic features are unlikely to improve discriminability. PMID:19174599

  15. The Semen pH Affects Sperm Motility and Capacitation.

    Directory of Open Access Journals (Sweden)

    Ji Zhou

    Full Text Available As the chemical environment of semen can have a profound effect on sperm quality, we examined the effect of pH on the motility, viability and capacitation of human sperm. The sperm in this study was collected from healthy males to avoid interference from other factors. The spermatozoa cultured in sperm nutrition solution at pH 5.2, 6.2, 7.2 and 8.2 were analyzed for sperm total motility, progressive motility (PR, hypo-osmotic swelling (HOS rate, and sperm penetration. Our results showed that these parameters were similar in pH 7.2 and 8.2 sperm nutrition solutions, but decreased in pH 5.2 and 6.2 solutions. The HOS rate exhibited positive correlation with the sperm total motility and PR. In addition, the sperm Na(+/K(+-ATPase activity at different pHs was measured, and the enzyme activity was significantly lower in pH 5.2 and 6.2 media, comparing with that in pH 8.2 and pH 7.2 solutions. Using flow cytometry (FCM and laser confocal scanning microscopy (LCSM analysis, the intracellular Ca2(+ concentrations of sperm cultured in sperm capacitation solution at pH 5.2, 6.2, 7.2 and 8.2 were determined. Compared with that at pH 7.2, the mean fluorescence intensity of sperm in pH 5.2 and 6.2 media decreased significantly, while that of pH 8.2 group showed no difference. Our results suggested that the declined Na(+/K(+-ATPase activity at acidic pHs result in decreased sperm movement and capacitation, which could be one of the mechanisms of male infertility.

  16. Modeling neuronal vulnerability in ALS.

    Science.gov (United States)

    Roselli, Francesco; Caroni, Pico

    2014-08-20

    Using computational models of motor neuron ion fluxes, firing properties, and energy requirements, Le Masson et al. (2014) reveal how local imbalances in energy homeostasis may self-amplify and contribute to neurodegeneration in ALS.

  17. AL-USRCRN Station Information

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Documentation of United States Alabama Regional Climate Reference Network (AL-USRCRN) installations in 2006. Installations documented are for AL-USRCRN pilot...

  18. ICT als medicijn tegen onveiligheid

    OpenAIRE

    Linders, Lilian; Steyaert, Jan

    2002-01-01

    Hoe verhoudt ICT zich tot veiligheid? SQM zou niet 'ict oplossingen voor sociale kwesties' als ondertitel hebben, als we geen aandacht gaven aan deze vraag. In de eerste Rode Draad Notitie verkent SQM dit thema.

  19. Corrosion of Mechanically Alloyed Nanostructured FeAl Intermetallic Powders

    Directory of Open Access Journals (Sweden)

    A. Torres-Islas

    2012-01-01

    Full Text Available The corrosion behavior of the Fe40Al60 nanostructured intermetallic composition was studied using electrochemical impedance spectroscopy (EIS and linear polarization resistance (LPR techniques with an innovative electrochemical cell arrangement. The Fe40Al60 (% at intermetallic composition was obtained by mechanical alloying using elemental powders of Fe (99.99% and Al (99.99%. All electrochemical testing was carried out in Fe40Al60 particles that were in water with different pH values. Temperature and test time were also varied. The experimental data was analyzed as an indicator of the monitoring of the particle corrosion current density icorr. Different oxide types that were formed at surface particle were found. These oxides promote two types of surface corrosion mechanisms: (i diffusion and (ii charge transfer mechanisms, which are a function of icorr behavior of the solution, pH, temperature, and test time. The intermetallic was characterized before and after each test by transmission electron microscopy. Furthermore, the results show that at the surface particles uniform corrosion takes place. These results confirm that it is possible to sense the nanoparticle corrosion behavior by EIS and LPR conventional electrochemical techniques.

  20. Luminescence of photoactivated pristine and Cr-doped MgAl2O4 spinel

    Science.gov (United States)

    Artemyeva, E. S.; Barinov, D. S.; Atitar, F. M.; Murashkina, A. A.; Emeline, A. V.; Serpone, N.

    2015-04-01

    This Letter reports a comparative study of the luminescence from pristine and Cr-doped MgAl2O4 spinel induced by different excitation mechanisms: photoluminescence (PhL), thermoluminescence (ThL) and Photo-Induced Chemisorption Luminescence (the PhICL phenomenon) to understand the mechanism of PhICL emission. Cr-doping alters the major pathway of physical relaxation through a luminescence pathway: quenching of the luminescence associated with intrinsic defects and appearance of the luminescence from Cr3+-states. The similarity between ThL and PhICL spectra suggest the mechanism of the PhICL phenomenon is due to electron transfer from the surface to the emission centers of luminescence; an energy transfer pathway is not precluded.

  1. Gliricidia sepium al establecimiento

    Directory of Open Access Journals (Sweden)

    J. L. Valle

    2004-01-01

    Full Text Available Se asoció Cenchrus ciliaris (Cc y Gliricidia sepium (Gs para evaluar la producción de biomasa y la composición química de los forrajes en la fase de establecimiento, en el estado de Morelos, México, en condiciones de trópico seco. Se empleó un análisis de varianza con diseño en bloques al azar, en donde T1 fue pasto solo, T2 Cc más Gs con 5,000 plantas ha-1 y el T3 Cs más Gs con 14,285 plantas ha-1. Se midió la producción de forraje individual y asociado con materia seca (t MS/Ha, la altura (A en cm, la proteína cruda (PC%, las fracciones de fibra (FDN% y FDA% y la digestibilidad in vitro de la materia seca (DIVMS%. El T3 tuvo una mejor producción de biomasa (P0.05. La asociación de 14,285 plantas ha-1 de G. sepium con pasto Cenchrus ciliaris mejoró la producción de biomasa y la disponibilidad total de nutrientes por superficie cultivada al establecimiento

  2. Derivados vinculados al seguro.

    Directory of Open Access Journals (Sweden)

    De Paz Cobo, Sonia

    2003-01-01

    Full Text Available El presente trabajo tiene como objetivo la presentación de los derivados financieros como instrumentos de cobertura de los riesgos del seguro, así como de los principales proyectos que se desarrollan a través de los mismos, como por ejemplo los derivados sobre el clima. Hay que tener presente las pérdidas multimillonarias ocasionadas en casos como el de la banca Baring’s, o el de Orange County, por citar algunas, que si bien ciertos autores afirman que están en relación directa con el uso de estos productos, no podemos olvidar que los instrumentos derivados se desarrollaron con el objetivo principal de proteger al usuario de la posible volatilidad del activo subyacente. Ya en la industria aseguradora los derivados vinculados a tal actividad son instrumentos donde el pago se condiciona a la ocurrencia de su suceso de siniestro, o serie de sucesos múltiples que disparen las pérdidas. Tras el repaso efectuado y la descripción que este tipo de instrumentos puede tener en la gestión del riesgo por parte de la industria aseguradora, concluiremos con la exposición de las relaciones con el reaseguro tradicional así como una breve referencia al futuro de este tipo de instrumentos

  3. The Early Development of Electronic pH Meters

    Science.gov (United States)

    Hines, Wallis G.; de Levie, Robert

    2010-01-01

    A 19-year-old undergraduate at the University of Chicago, Kenneth Goode, in 1921 came up with the idea of an electronic pH meter, worked out some of its initial problems, and set in motion an international scientific effort that culminated in the current, wide availability of electronic pH meters. Except for the replacement of vacuum tubes by…

  4. Consideration of Factors Affecting Strip Effluent PH and Sodium Content

    Energy Technology Data Exchange (ETDEWEB)

    Peters, T. [Savannah River Site (SRS), Aiken, SC (United States)

    2015-07-29

    A number of factors were investigated to determine possible reasons for why the Strip Effluent (SE) can sometimes have higher than expected pH values and/or sodium content, both of which have prescribed limits. All of the factors likely have some impact on the pH values and Na content.

  5. Microscale pH Titrations Using an Automatic Pipet.

    Science.gov (United States)

    Flint, Edward B.; Kortz, Carrie L.; Taylor, Max A.

    2002-01-01

    Presents a microscale pH titration technique that utilizes an automatic pipet. A small aliquot (1-5 mL) of the analyte solution is titrated with repeated additions of titrant, and the pH is determined after each delivery. The equivalence point is determined graphically by either the second derivative method or a Gran plot. The pipet can be…

  6. Tracking the PhD Students' Daily Computer Use

    Science.gov (United States)

    Sim, Kwong Nui; van der Meer, Jacques

    2015-01-01

    This study investigated PhD students' computer activities in their daily research practice. Software that tracks computer usage (Manic Time) was installed on the computers of nine PhD students, who were at their early, mid and final stage in doing their doctoral research in four different discipline areas (Commerce, Humanities, Health Sciences and…

  7. Proteolytische activiteit bij neutrale pH in rundermilt

    NARCIS (Netherlands)

    Marrink, Jan

    1969-01-01

    Intracellular enzymes, hydrolysing proteins optimally at acid pH values (acid proteases), have been studied in detail by several investigators. The existence of proteolytic activity at neutral pH in animal tissue extracts, on the other hand, has often been mentioned, but with few reports on the isol

  8. Sulfate reduction at low pH in organic wastewaters

    NARCIS (Netherlands)

    Lopes, S.I.C.

    2007-01-01

    The objective of the research described in this thesis was to investigate the operational window of dissimilatory sulfate reduction at low pH (6, 5 and 4) during the acidification of organic wastewaters. High sulfate reduction efficiencies at low pH are desirable for a more sustainable operation of

  9. Predicting Computer Science Ph.D. Completion: A Case Study

    Science.gov (United States)

    Cox, G. W.; Hughes, W. E., Jr.; Etzkorn, L. H.; Weisskopf, M. E.

    2009-01-01

    This paper presents the results of an analysis of indicators that can be used to predict whether a student will succeed in a Computer Science Ph.D. program. The analysis was conducted by studying the records of 75 students who have been in the Computer Science Ph.D. program of the University of Alabama in Huntsville. Seventy-seven variables were…

  10. PhD-project Robust and Agile Planning

    NARCIS (Netherlands)

    Evers, L.

    2013-01-01

    The PhD research by Lanah Evers is a collaborative research project between TNO, the Netherlands Defence Academy (NLDA) and the Erasmus University of Rotterdam and aims to develop robust and agile planning methods for military operations. This PhD research is supervised by Dr. A. Barros (TNO), who i

  11. Ureolytic nitrification at low pH by Nitrosospira spec.

    NARCIS (Netherlands)

    De Boer, W.; Laanbroek, R.

    1989-01-01

    An ureolytic ammonium-oxidizing chemolithotroph belonging to the genus Nitrosospira was shown to nitrify at pH 4.5 in a pH-stat with urea as a substrate. With ammonium as the sole substrate nitrification did not occur at pH values below 5.5. Nitrosomonas europaea ATCC 19718 and Nitrosospira briensis

  12. Optic nerve pH and PO2

    DEFF Research Database (Denmark)

    Pedersen, Daniella B; Stefánsson, Einar; Kiilgaard, Jens Folke;

    2006-01-01

    how optic nerve pH (ONpH) and ONPO(2) are affected by: (1) carbonic anhydrase inhibition; (2) respiratory acidosis, and (3) metabolic acidosis. We measured ONpH with a glass pH electrode and ONPO(2) with a polarographic oxygen electrode. One of the electrodes was placed in the vitreous cavity 0.5 mm...

  13. What if We Made Fewer Ph.D.'s?

    Science.gov (United States)

    Cassuto, Leonard

    2012-01-01

    Whenever a discussion opens about nonacademic employment for Ph.D.s, it is not long before someone suggests reducing graduate-school admissions. "The market for full-time scholars has fallen off a cliff lately," this argument goes, "so why not just train fewer of them?" The strategy to reduce the number of Ph.D. students recurs in those…

  14. P-H bonds in the reconstruction of P-rich InP(100) measured with FTIR

    Science.gov (United States)

    Letzig, T.; Willig, F.

    2006-08-01

    The reconstruction of P-rich InP(100) requires at least a (2x4) surface unit cell to stay semiconducting and uncharged (electron counting rule). Recently it has been shown that the much smaller (2x2) unit cell obtained from MOCVD (metalorganic vapor deposition) growth contains P-H bonds. Orientation and polarization dependent Fourier Transform Infrared Spectroscopy (FTIR) of the P-H bonds in the Attenuated Total Reflection (ATR) mode have confirmed the specific form of the (2x2) surface unit cell (T. Letzig et al., Phys. Rev. B 71 (2005) 033308) earlier proposed by W.G. Schmidt and coworkers (W.G. Schmidt et al., Phys. Rev. Lett. 90 (2003) 126101). Surface unit cells with a higher concentration of P-H bonds also obey the electron counting rule. A c(2x2) LEED image and two matching FTIR peaks were observed when the (2x2) reconstructed surface was exposed to atomic hydrogen. The corresponding c(2x2)-2P-3H surface unit cell can be shown to form a stable surface phase (T. Letzig et al., Phys. Rev. B, submitted). The complete transformation of the (2x2) surface to this new phase is not observed since the surface deteriorates when exposed to a higher dose of atomic hydrogen.

  15. Analysis list: ph-d [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ph-d Cell line,Embryo + dm3 http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/target/p...h-d.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/target/ph-d.5.tsv http://dbarchive.biosciencedbc.jp.../kyushu-u/dm3/target/ph-d.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/colo/ph-d.Cell_line.tsv,http://dbarchive.bioscien...cedbc.jp/kyushu-u/dm3/colo/ph-d.Embryo.tsv http://dbarchive.bioscien...cedbc.jp/kyushu-u/dm3/colo/Cell_line.gml,http://dbarchive.biosciencedbc.jp/kyushu-u/dm3/colo/Embryo.gml ...

  16. Nanosensors for pH measurements in plants

    DEFF Research Database (Denmark)

    Ytting, Cecilie Karkov; Fuglsang, Anja Thoe

    Traditionally in vivo pH measurements in plants are carried out using different fluorescent probes such as BCECF and SNARFs by injecting plant cells or incubating tissues with the probes. This approach, however, carries several problems, the most important one being the handling of the plant cells...... of the green fluorescent protein, GFP, have become available, some of which are pH sensitive. This offers the opportunity to simply express the pH sensitive protein in different plant tissues, making it possible to conduct in vivo pH measurements in a non-invasive manner. One sensor being characterized...... or tissues. Stress and wounding of the plant can possibly influence the outcome of the pH measurements. Other problems are the difficulties of getting the probes more than a few cell layers into the plant tissue and to get an even distribution of the probe. Increasing numbers of different variants...

  17. Ratiometric Fluorescent pH Probes Based on Glycopolymers.

    Science.gov (United States)

    Li, Zhiyun; Zhang, Pengshan; Lu, Wei; Peng, Lun; Zhao, Yun; Chen, Gaojian

    2016-09-01

    Effectively detecting pH changes plays a critical role in exploring cellular functions and determining physiological and pathological processes. A novel ratiometric pH probe based on a glycopolymer, armored with properties of serum-stability, tumor-targeting, and pH monitoring, is designed. Random copolymers of 2-(methacrylamido) glucopyranose and fluorescein O-methacrylate are first synthesized by reversible addition fragmentation chain transfer polymerization. Acryloxyethyl thiocarbamoyl rhodamine B is then attached to the polymer chain to prepare ratiometric fluorescent pH probes via a thiol-ene reaction. The synthesized polymeric probes are characterized by NMR, gel permeation chromatography, UV-vis spectroscopy, and transmission electron microscopy, and the fluorescence responses are examined in phosphate buffer at different pHs. The cytotoxicity and confocal imaging experiments of the probes are detected using HeLa cells, demonstrating a low toxicity and superior biocompatibility for detecting pH changes in bioapplications. PMID:27439338

  18. Ante Šiljeg, PhD in Interdisciplinary Sciences

    Directory of Open Access Journals (Sweden)

    Sanja Lozić

    2013-12-01

    Full Text Available Ante Šiljeg defended his doctoral thesis The Digital Relief Model in Analysis of Geomorphometric Parameters – Example of PP Vrana Lake at Faculty of Science, University of Zagreb on June 20th, 2013 (supervisor Sanja Lozić, PhD, assistant professor and received a PhD degree in the field of interdisciplinary science, field of geography, branch of applied geography. Doctoral thesis was defended in front of committee composed of Mladen Pahernik, PhD, assistant professor, Danijel Orešić, PhD, associate professor and Aleksandar Toskić, PhD, associate professor. Commitee for disertation review was in the same composition.

  19. ['Sandwich PhD': considerations for a successful experience abroad].

    Science.gov (United States)

    Salvetti, Marina de Goes; Bueno, Mariana; Gastaldo, Denise; Kimura, Amélia Fumiko; Pimenta, Cibele Andrucioli de Mattos

    2013-03-01

    International PhD internship, named "Sandwich PhD" in Brazil is an opportunity to improve research abilities, to become known in academic area and to establish and/or increase work opportunities in an international context. In this article, we describe key factors regarding the planning and development of the "Sandwich PhD" as experienced by professors and students involved in the collaboration between the School of Nursing, University of São Paulo and Lawrence S. Bloomberg Faculty of Nursing, University of Toronto, Canada. We also present the participation of PhD students' network as an alternative to the "Sandwich PhD". An international experience, when well-planned and developed correctly, promotes students' personal and professional development and favors the internationalization of Brazilian graduate programs and research groups.

  20. Biolixiviação de metais do lodo de curtume em duas etapas: influência do pH = Bioleaching of metals from tannery sludge in two stages: effect of pH

    Directory of Open Access Journals (Sweden)

    Fábio Moreira da Silva

    2009-04-01

    Full Text Available O presente trabalho avaliou a influência do pH final sobre a biolixiviação de Cr e outros metais do lodo de curtume, utilizando um sistema com a separação das etapas de oxidação biológica do enxofre elementar e de lixiviação do resíduo. A concentração de enxofre elementar foi de 5 g L-1. O pH final de biolixiviação variou de 3,0 a 1,0. A concentração de sólidos do lodo de curtume lixiviado foi de 100 g L-1 e as temperaturas foram de 298,15 e 308,15 K. As porcentagens de extração de Al, Cr e Zn tiveram acréscimos para menores valores de pH final, enquanto as de Ca decresceram nessas condições. A extração máxima de Cr foi de 70,11% em concentração de sólidos do lodo de 100 g L-1, pH final de 1,0 e temperatura de 298,15 K. A fração de Cr ligada aos óxidos de Fe e Mn teve maior variação no teor do metal do que as outras frações, pelas mudanças de pH final. Arazão em massa dos metais e do Cr decresceu para menores valores de pH final. A concentração de Cr lixiviado do lodo de curtume, após a biolixiviação em pH final 1,0, foi reduzida a valores satisfatórios.The present work assessed the effect of the pH in the bioleaching of Cr and other metals from tannery sludge with stage separation of biologic oxidation of elemental sulfur and leaching of solid waste. The concentration of elemental sulfur was 5 g L-1. The finalbioleaching pH ranged from 3.0 to 1.0. The concentration of sludge solids was 100 g L-1 and the temperatures were 298.15 and 308.15 K. The leaching extractions of Al, Cr and Zn increased at lower final pH and the leaching extraction of Ca decreased in this condition.The maximum extraction of Cr was 70.11% at sludge solids concentration of 100 g L-1, final pH 1.0 and temperature of 298.15 K. The fraction of Cr bound to Fe and Mn oxides was more affected by changes at final pH than others fractions. The mass ratio of metals and Cr decreased at lower final pH. The concentration of Cr leached from

  1. Plant based dietary supplement increases urinary pH

    Directory of Open Access Journals (Sweden)

    Rao A Venket

    2008-11-01

    Full Text Available Abstract Background Research has demonstrated that the net acid load of the typical Western diet has the potential to influence many aspects of human health, including osteoporosis risk/progression; obesity; cardiovascular disease risk/progression; and overall well-being. As urinary pH provides a reliable surrogate measure for dietary acid load, this study examined whether a plant-based dietary supplement, one marketed to increase alkalinity, impacts urinary pH as advertised. Methods Using pH test strips, the urinary pH of 34 healthy men and women (33.9 +/- 1.57 y, 79.3 +/- 3.1 kg was measured for seven days to establish a baseline urinary pH without supplementation. After this initial baseline period, urinary pH was measured for an additional 14 days while participants ingested the plant-based nutritional supplement. At the end of the investigation, pH values at baseline and during the treatment period were compared to determine the efficacy of the supplement. Results Mean urinary pH statistically increased (p = 0.03 with the plant-based dietary supplement. Mean urinary pH was 6.07 +/- 0.04 during the baseline period and increased to 6.21 +/- 0.03 during the first week of treatment and to 6.27 +/- 0.06 during the second week of treatment. Conclusion Supplementation with a plant-based dietary product for at least seven days increases urinary pH, potentially increasing the alkalinity of the body.

  2. Impact of ruminal pH on enteric methane emissions.

    Science.gov (United States)

    Hünerberg, M; McGinn, S M; Beauchemin, K A; Entz, T; Okine, E K; Harstad, O M; McAllister, T A

    2015-04-01

    The objective of this study was to determine the impact of ruminal pH on methane (CH4) emission from beef cattle. Ruminal pH and CH4 data were generated in 2 experiments using 16 beef heifers offered high-forage (55% barley silage) or high-grain (92% concentrate; DM basis) diets. Both experiments were designed as a replicated 4 × 4 Latin square with 4 periods and 4 dietary treatments. Methane was measured over 4 consecutive days using open-circuit respiratory chambers with each chamber housing 2 heifers. The ruminal pH of individual heifers was measured using indwelling pH loggers. The mean ruminal pH and CH4 emission (g/h) of 2 heifers in every chamber were summarized in 30-min blocks. Even though rumen methanogens have been described to be inhibited by a pH 0.05). Daily mean CH4 emission (g/d) and ruminal pH were only mildly correlated (r2 = 0.27; P < 0.05), suggesting that additional factors, such as increased propionate formation or passage rate, account for the lower CH4 emissions from cattle fed high-grain as compared to high-forage diets. Lowering ruminal pH alone is, therefore, not an effective CH4-mitigation strategy. Mechanisms permitting methanogens to survive episodes of low-ruminal pH might include changes in community structure toward more pH-tolerant strains or sequestration into microenvironments within biofilms or protozoa where methanogens are protected from low pH. PMID:26020197

  3. O pH das soluções nutritivas no comportamento de cultivares de trigo à toxicidade de alumínio Effect of pH in nutrient solution on tolerance to aluminum toxicity in wheat cultivars

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo de Oliveira Camargo

    1984-01-01

    Full Text Available Foram estudados nove cultivares de trigo em soluções nutritivas contendo quatro níveis de alumínio (0, 5, 10 e 20mg/litro combinados com três níveis de pH (4,0, 5,0 e 6,0. A tolerância foi medida pela capacidade de as raízes primárias continuarem a crescer em solução sem alumínio, após um período de permanência de 48 horas em solução contendo determinados níveis de pH e de alumínio. Os cultivares BH-1146, IAC-18, IAC-13 e C-3 foram tolerantes; IAC-17 e Alondra-4546 foram moderadamente tolerantes, e Síete Cerros, Super-x e CNT-8 foram sensíveis à presença de quantidades crescentes de Al3+ nas soluções de tratamentos quando foi mantido o pH 4,0. Todos os cultivares foram tolerantes às dosagens de alumínio estudadas quando foram mantidos os níveis de pH 5,0 ou 6,0. Ficou confirmado que um controle rigoroso do pH da solução tratamento é um fator de grande importância no estudo da toxicidade do alumínio a diferentes cultivares de trigo.The aluminum tolerance of nine wheat cultivars was studied in nutrient solutions using three different levels of pH combined with four different concentrations of this element. The tolerance was evaluated by measuring the root growth in an aluminum-free complete nutrient solution after a previous treatment in aluminum added solutions (0, 5, 10 and 20mg/l under a particular pH (4.0, 5.0 and 6.0. The wheat cultivars BH-1146, IAC-18, IAC-13 and C-3 presented tolerance, IAC-17 and Alondra-4546 showed moderate tolerance and Siete Cerros, Super-x and CNT-8 were sensitive to the presence of increasing concentrations of Al3+ in the treatment solution under pH 4.0. All cultivars were tolerant to the different concentrations of aluminum under pH 5.0 and 6.0. The aluminum toxicity symptom (inhibition of root growth was dependent on the pH and the amount of aluminum in the treatment solution. For the same level of aluminum, toxicity symptoms increased, when the pH decreased in the solution from 6

  4. Ambulatory oesophageal pH monitoring : a comparison between antimony, ISFET, and glass pH electrodes

    NARCIS (Netherlands)

    Hemmink, Gerrit J. M.; Weusten, Bas L. A. M.; Oors, Jac; Bredenoord, Albert J.; Timmer, Robin; Smout, Andre J. P. M.

    2010-01-01

    Background and aim Ambulatory oesophageal pH-impedance monitoring is a widely used test to evaluate patients with reflux symptoms. Several types of pH electrodes are available: antimony, ion sensitive field effect transistor (ISFET), and glass electrodes. These pH electrodes have not been compared d

  5. Synthesis of YAG nanopowder by the co-precipitation method: Influence of pH and study of the reaction mechanisms

    International Nuclear Information System (INIS)

    YAG nanopowders with an average grain size of 30 nm have been successfully synthesized by the co-precipitation method using nitrates with precipitant of ammonium hydrogen carbonate. The influence of precipitation conditions such as pH, aging time and calcination temperature on the formation of secondary phases has been studied. The accurate control of pH value at every stage of precipitation process is crucial to avoid the presence of YAM (Yttrium Aluminium Monoclinic, Y4Al2O9) and yttrium oxide (Y2O3) after calcination. The reaction mechanisms have been investigated using different techniques such as infrared spectroscopy, x-ray diffraction and thermal analyses. The YAG phase is formed around 1050 °C passing through an intermediate phase called YAP (Yttrium Aluminium Perovskite, YAlO3). Local chemical heterogeneities are responsible for the deviation of the Y:Al ratio and the formation of YAP during heat treatment. - Graphical abstract: Synthesis of YAG nanopowder by the co-precipitation method: Influence of pH and study of the reaction mechanisms, Marlot et al. Highlights: ► Synthesis of pure YAG nanoparticles by the co-precipitation method. ► Influence of pH value on the formation of secondary phases all along the process. ► Study of the importance of pH using titration method. ► Chemical evolution of the precursor during calcinations. ► Proposition for reaction mechanisms.

  6. Corrosion behaviour of Al/SiC and Al/Al2O3 nanocomposites

    Directory of Open Access Journals (Sweden)

    Tamer Samir Mahmoud

    2012-12-01

    Full Text Available In the present investigation, the static immersion corrosion behavior of Al/Al2O3 and Al/SiC nanocomposites in 1 M HCl acidic solution was evaluated. The nanocomposites were fabricated using conventional powder metallurgy (P/M route. The effect of nanoparticulates size and volume fraction on the corrosion behavior of nanocomposites was studied. The durations of the corrosion tests ranged from 24 to 120 hours and the temperatures of the solution ranged from ambient to 75 ºC. The corrosion rates of the nanocomposites were calculated using the weight loss method. The results showed that both Al/SiC and Al/Al2O3 MMNCs have lower corrosion rates than the pure Al matrix. Such behavior was noticed at both ambient and higher temperatures. Generally, the Al/Al2O3 nanocomposites exhibited lower corrosion rates than the Al/SiC nanocomposites. The Al/Al2O3 (60 nm nanocomposites exhibited the highest corrosion resistance among all the investigated nanocomposites. The corrosion rate was found to be reduced by increasing of the exposure time and the volume fraction of the nanoparticulates, while it was found to be increased by increasing of the nanoparticulates size and the solution temperature.

  7. Doppelthydrophile Blockcopolymere als Mineralisationstemplate

    Science.gov (United States)

    Kasparova, Pavla

    2002-07-01

    Die vorliegende Arbeit beschäftigt sich mit der Synthese und den Eigenschaften von doppelthydrophilen Blockcopolymeren und ihrer Anwendung in einem biomimetischen Mineralisationsprozeß von Calciumcarbonat und Bariumsulfat. Doppelthydrophile Blockcopolymere bestehen aus einem hydrophilen Block, der nicht mit Mineralien wechselwirkt und einem zweiten Polyelektrolyt-Block, der stark mit Mineraloberflächen wechselwirkt. Diese Blockcopolymere wurden durch ringöffnende Polymerisation von N-carboxyanhydriden (NCA's) und a-methoxy-ω-amino[poly(ethylene glycol)] PEG-NH2 als Initiator hergestellt. Die hergestellten Blockcopolymere wurden als effektive Wachstumsmodifikatoren für die Kristallisation von Calciumcarbonat und Bariumsulfat Mineralien eingesetzt. Die so erhaltenen Mineralpartikel (Kugeln, Hantel, eiförmige Partikel) wurden durch Lichtmikroskopie in Lösung, SEM und TEM charakterisiert. Röntgenweitwinkelstreuung (WAXS) wurde verwendet, um die Modifikation von Calciumcarbonat zu ermitteln und die Größe der Calciumcarbonat- und Bariumsulfat-Nanopartikel zu ermitteln. This work describes the synthesis and characterization of double hydrophilic block copolymers and their use in a biomimetic mineralization process of Calcium Carbonate and Barium Sulfate. Double hydrophilic block copolymers consist of a hydrophilic block that does not interact with minerals and another hydrophilic polyelectrolyte block that strongly interacts with mineral surfaces. These polymers were synthesised via ring opening polymerisation of N-carboxyanhydride (NCA), and the first hydrophilic block a-methoxy-ω-amino[poly(ethylene glycol)] PEG-NH2 was used as an initiator. The prepared block copolymers were used as effective crystal growth modifiers to control the crystallization of Calcium Carbonate and Barium Sulfate minerals. The resulting mineral particles (spheres, dumbbells, egg-like particles) were characterised by light microscopy in solution, by SEM, and by TEM. X-Ray scattering

  8. COMENTARIO AL CASO PINOCHET

    Directory of Open Access Journals (Sweden)

    Alberto Contreras Clunes

    2002-01-01

    Full Text Available El fallo en el caso Pinochet tiene distintas formas de ser analizado. De partida, desde un punto de vista político, también constitucional, del derecho penal. Sin embargo, nos abocaremos al estudio desde el punto de vista procesal, en especial a lo referido al Debido Proceso. Para ello se analizará los presupuestos, la solución dada por la Excma. Corte Suprema y las consecuencias del mismo. Además, se criticará la solución dada, desde la óptica de las garantías procesales del imputado, contenidas en el nuevo proceso penal y lo dispuesto en la Constitución y la Convención Americana de Derechos Humanos. Finalmente, se argumentará en favor de una interpretación finalista y armónica de la Constitución y los tratados internacionales de derechos humanos.The verdict of the Pinochet Case has different ways of being analyzed: from the political, the constitutional, and the penal law points of view. However, we will approach this study from the legal point of view, especially to that referred to as the Proper Process. To do this, the budgets, the solution given by the Most Excellent Supreme Court, and its consequences will be analyzed. Furthermore, the given solution will be criticized from the point of view of the legal guarantees of the accused contained in the new penal process and what is contained in the Constitution and in the American Convention of Human Rights. In conclusion, we will argue in favor of a final and harmonious interpretation of the Constitution and the international agreement of human rights.

  9. MgAl2O4 Ultrafiltration Ceramic Membrane Derived from Mg-Al Double Alkoxide%铝镁双醇盐制备MgAl2O4尖晶石陶瓷超滤膜

    Institute of Scientific and Technical Information of China (English)

    张国昌; 陈运法; 吴振江; 谢裕生

    2000-01-01

    Spinel (MgAl2O4) ultrafiltration membranes were prepared on porous α-Al2O3 plates via the sol-gel route. Mg-Al double alkoxide [MgAl2(iprO)s] was first synthesized as the precursor, then hydrolyzed and peptized in aqueous solution. The gel layer was coated from the colloidal sol on the intermediate layer (α-Al2O3), which was formerly prepared to modify the porous substrate, and then thermally treated at 900℃. The processing parameters such as pH, temperature and sol composition during the sol preparation were optimized for controlling particle size. The pore size of the 2μm thick top layer is about 13 nm as estimated by both the BSA (Bovine Serum Albumin)retention test and an empirical equation.The water permeability of the obtained spinel membrane is 55~143 kg/(min.cm2.Pa).

  10. Epitaxial growth of Al/Al2O3 multilayer structures

    International Nuclear Information System (INIS)

    In order to obtain Al-Al2O3 quantum effect devices, it is necessary to deposit epitaxially Al on Al2O3 and Al2O3 on Al. We have already obtained an epitaxial Al/Al2O3/Al structures on Si(111). In this paper, we have deposit Al/Al2O3/Al structures on Si(111), and investigated the crystallinity by using RBS. (author)

  11. Development of an accurate pH measurement methodology for the pore fluids of low pH cementitious materials

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, M. C.; Garcia Calvo, J. L. [The Spanish National Research Council (CSIC), Madrid (Spain); Walker, C. [Japan Atomic Energy Agency (JAEA), Ibaraki (Japan)] [and others

    2012-08-15

    The main objective of this project has been the development of an agreed set of protocols for the pH measurement of the pore fluid of a low pH cementitious material. Three protocols have been developed (Chapter 2), a reference method, based on pore fluid expression (PFE), and two routine methods with and without filtering, based on Ex Situ Leaching (ESL) procedures. Templates have been designed on which to record details of the pH measurement for the reference (PFE) method (Appendix C) and the routine (ESL) methods without and with filtering (Appendix D). Preliminary protocols were based on a broad review of the literature (Appendix A) and refined through a series of test experiments of the more critical parameters (Appendix B). After definition of the preliminary protocols, two phases of interlaboratory tests were performed. The first phase (Chapter 3) used the same low pH cement paste and enabled the nine participating laboratories to use, become familiar with and to identify any problems/uncertainties in the preliminary protocols. The reported pH values were subjected to a statistical analysis of the (within laboratory) repeatability and (between-laboratory) reproducibility and so provided a reliability test of the preliminary protocols. The second phase (Chapter 4) of interlaboratory tests used four different candidate low pH cementitious materials in the same nine laboratories, which allowed testing, validation and comparison of the reported pH values, which were obtained using the final protocols for the reference (PFE) and routine (ESL) methods by statistical analysis. The proposed final protocols (Chapter 2) have resulted in the reported pH values having low deviation and high reproducibility and repeatability. This will allow confidence in the pH value when selecting a candidate low pH cementitious material to be used in the engineered component of a high-level nuclear waste repository.

  12. Development of an accurate pH measurement methodology for the pore fluids of low pH cementitious materials

    International Nuclear Information System (INIS)

    The main objective of this project has been the development of an agreed set of protocols for the pH measurement of the pore fluid of a low pH cementitious material. Three protocols have been developed (Chapter 2), a reference method, based on pore fluid expression (PFE), and two routine methods with and without filtering, based on Ex Situ Leaching (ESL) procedures. Templates have been designed on which to record details of the pH measurement for the reference (PFE) method (Appendix C) and the routine (ESL) methods without and with filtering (Appendix D). Preliminary protocols were based on a broad review of the literature (Appendix A) and refined through a series of test experiments of the more critical parameters (Appendix B). After definition of the preliminary protocols, two phases of interlaboratory tests were performed. The first phase (Chapter 3) used the same low pH cement paste and enabled the nine participating laboratories to use, become familiar with and to identify any problems/uncertainties in the preliminary protocols. The reported pH values were subjected to a statistical analysis of the (within laboratory) repeatability and (between-laboratory) reproducibility and so provided a reliability test of the preliminary protocols. The second phase (Chapter 4) of interlaboratory tests used four different candidate low pH cementitious materials in the same nine laboratories, which allowed testing, validation and comparison of the reported pH values, which were obtained using the final protocols for the reference (PFE) and routine (ESL) methods by statistical analysis. The proposed final protocols (Chapter 2) have resulted in the reported pH values having low deviation and high reproducibility and repeatability. This will allow confidence in the pH value when selecting a candidate low pH cementitious material to be used in the engineered component of a high-level nuclear waste repository

  13. Study on steel matrix composites with (Ti,Al)N gradient PVD coatings

    OpenAIRE

    G. Matula

    2009-01-01

    Purpose: The paper presents investigation results of structure and properties of steel matrix composites (SMC) uncoated and coated with hard (Ti,Al)N gradient coatings with use of physical vapour deposition process.Design/methodology/approach: Powder Metallurgy, PVD, TEM, SEM, XRD, GDOES, Microhardness tests, Scratch test.Findings: Depositing of gradient (Ti,Al)N coatings onto SMC materials meets the requirements connected with hybrid technology of production, joining powder metallurgy and ph...

  14. Measuring pH in low ionic strength glacial meltwaters

    Science.gov (United States)

    Bagshaw, Elizabeth; Beaton, Alex; Wadham, Jemma; Mowlem, Matt; Tranter, Martyn

    2014-05-01

    pH is a fundamental indicator of the biogeochemical status of natural waters, but it remains challenging to measure reliably in the field. Glacial meltwaters are particularly problematic since they have low ionic strength, and pH values range from less than neutral (high: pH 11 is not uncommon in supraglacial ecosystems and bulk runoff frequently exceeds pH 9 in the height of summer. Meltwaters are also at disequilibrium with the atmosphere, and so immediate measurement is necessary to capture the true pH of the system. Varying flow rates and changing temperature can affect pH, so these parameters and their impacts on the measurement technology in question must be quantified. There are three primary approaches to measuring pH in natural waters: potentiometric, spectrophotometric and fluorescent. We discuss their applicability to glacial systems, via a series of comprehensive laboratory tests at low temperatures and low ionic strengths. The Honeywell Durafet system, a potentiometric ion sensitive field effect transistor (ISFET) sensor which has been successfully demonstrated in long-term ocean monitoring, was the most effective in tests. We present the results of a 60 day deployment of the sensor in glacial outflows from the Greenland ice sheet, and demonstrate its superiority to traditional monitoring solutions.

  15. Geoquímica de las aguas subterráneas en rocas metamórficas al SE de Salamanca

    Directory of Open Access Journals (Sweden)

    García, A.

    1991-08-01

    Full Text Available This paper describes the results of 77 chemical analyses of groundwater from springs and wells in the «Complejo Esquisto Grauváquico» and other paleozoic materials from the south of Salamanca province. The types of groundwater are very diverse, usually bicarbonate dominant, with TDS (Total Dissolved Solids between 0.6 and 16 milimoles/l. Salinity is shown to be greater in the drilled wells than in the dug wells and springs, which confirms the existence of deep flow. Principal Component Analysis indicates that the chemical composition of groundwater must be the result of multiple reactions between the water and the minerals that occur in parallel, with none of the reactions being specially predominant. The organization and geographic distribution of sorne of the elements suggest the existence of regional flow systems.Se presentan los resultados de 77 análisis químicos de aguas subterráneas procedentes de manantiales, pozos excavados y sondeos en el Complejo Esquisto Grauváquico y otros materiales paleozoicos al Sur de la provincia de Salamanca. Se trata de aguas muy dispares, en general bicarbonatadas mixtas, con TSD (total de sólidos disueltos entre 0,6 y 16 milimoles/l. Se pone de manifiesto una mayor salinidad de las aguas de sondeos en relación con las de pozos y manantiales, lo que demuestra la existencia de una circulación a cierta profundidad. El análisis de componentes principales muestra que la composición química de las aguas debe ser el resultado de múltiples reacciones entre el agua y los minerales que se producen en paralelo, sin que destaque ninguna en especial. La distribución geográfica ordenada de algunos elementos obliga a plantear como posible la hipótesis de la existencia de un flujo regional.

  16. Retention of chromium by modified Al-Bentonite Retenção de cromo por Al-bentonita modificada

    Directory of Open Access Journals (Sweden)

    C. Volzone

    2002-09-01

    Full Text Available Retention of chromium (III from a tanning wastewater by modified Al-bentonites was studied. One bentonite from San Juan province, Argentina, was used. Al-bentonite was prepared by contact of bentonite with hydrolyzed OH-Al solutions (0.10 M in Al for 24 hours. The modified Al-bentonites were obtained by: a treatment with 0.5 M sodium chloride; b with 0.5 M sodium chloride adjusted at pH 8; and c treatment with an hexametaphosphate solution after sodium addition. Then, the samples were dried at 100 °C and heated at 500 °C. The chromium (III retention by samples was carried out in batch system putting in contact the material with a 2000 ppm Cr tannery waste at different times. The retained chromium was characterized by analyzing the supernatant using UV-visible spectroscopy. The different chromium retention was correlated with structural characteristics of the solids.Foi estudada a retenção de cromo (III de águas residuais por meio de Al-bentonitas modificadas. Foi usada uma bentonita da província de San Juan, Argentina. As bentonitas-Al forma preparadas colocando-as em contato com soluções (0,10 M Al hydrolizadas de OH-Al durante 24 horas. As bentonitas-Al modidicadas foram obtidas por meio de: a tratamento com cloreto de sódio 0,5 M; b com cloreto de sódio 0,5 M sodium com pH ajustado para 8; e c tratamento com uma solução de hexametafosfato após a adição de sódio. As amostras foram então secas a 100 °C e aquecidas a 500 °C. A retenção do cromo (III pelas amostras foi feita em lotes colocando o material em contato em diferentes tempos com um resíduo contendo 2000 ppm de cromo. O cromo retido foi caracterizado por meio de análise do sobrenadante usando espectroscopia UV-visível. As diferentes retenções de cromo foram correlacionadas com características estruturais dos sólidos.

  17. Controls of Soluble Al in Experimental Acid Sulfate Conditions and Acid Sulfate Soils

    Institute of Scientific and Technical Information of China (English)

    LINCHUXIA; M.D.MELVILLE

    1997-01-01

    The controls of soluble Al concentration were examined in three situations of acid sulfate conditions:1) experimental acid sulfate conditions by addition of varying amounts of Al(OH)3(gibbsite) into a sequence of H2SO4 solutions;2)experimental acid sulfate conditions by addition of the same sequence of H2SO4 solutions into two non-cid sulfacte soil samples with known amounts of acid oxalate extractable Al; and 3) actual acid sulfate soil conditions.The experiment using gibbsite as an Al-bearing mineral showed that increase in the concentration of H2SO4 solution increased the soluble Al concentration,accompanied by a decrease i the solution pH, Increasing amount of gibbsite added to the H2SO4 solutions also increased soluble Al concentration,but resulted in an increase in solution pH.Within the H2SO4 concentration range of 0.0005-0.5mol L-1 and the Al(OH)3 range of 0.01-0.5g(in 25 mL of H2SO4 solutions),the input of H2SO4 had the major control on soluble Al Concentration and pH .The availability of Al(OH)3,however,was responsible for the spread fo the various sample points,with a tendency that the samples containing more gibbsite had a higher soluble Al concentration than those containing less gibbsite at equivalent pH levels.The experimental results from treatment of soil samples with H2SO4 solutions and the analytical results of acid sulfate soils also showed the similar trend.

  18. Umbilical cord blood pH in intrapartum hypoxia

    International Nuclear Information System (INIS)

    To determine the association of cord arterial blood pH with neonatal outcome in cases of intrapartum fetal hypoxia. Study Design: Descriptive analytical study. Place and Duration of Study: Gynaecology Unit-II, Civil Hospital, Karachi, from September 2011 to November 2012. Methodology: All singleton cephalic fetuses at term gestation were included in the study. Those with any anomaly, malpresentation, medical disorders, maternal age < 18 years, multiple gestation and ruptured membranes were excluded. Patients with abnormal cardiotocography and/or meconium stained liquor were enrolled as index case and immediate next delivery with no such signs as a control. Demographic characteristics, pH level < or > 7.25, neonatal outcome measures (healthy, NICU admission or neonatal death), color of liquor and mode of delivery recorded on predesigned proforma. Statistical analysis performed by SPSS 16 by using independent-t test or chi-square test and ANOVA test as needed. Results: A total of 204 newborns were evaluated. The mean pH level was found to be significantly different (p=0.007) in two groups. The pH value 7.25 had significant association (p < 0.001) with the neonatal outcome. However, the association of neonatal outcome with severity of acidemia was not found to be significant. Grading of Meconium Stained Liquor (MSL) also did not relate positively with pH levels as 85.7% of grade I, 68.9% of grade II and 59.4% of grade III MSL had pH > 7.25. Majority (63.6%) cases needed caesarean section as compared to 31.4% controls. Conclusion: There is a significant association of cord arterial blood pH at birth with neonatal outcome at pH < or > 7.25; but below the level of pH 7.25 it is still inconclusive. (author)

  19. Titratable acidity of beverages influences salivary pH recovery

    Directory of Open Access Journals (Sweden)

    Livia Maria Andaló TENUTA

    2015-01-01

    Full Text Available A low pH and a high titratable acidity of juices and cola-based beverages are relevant factors that contribute to dental erosion, but the relative importance of these properties to maintain salivary pH at demineralizing levels for long periods of time after drinking is unknown. In this crossover study conducted in vivo, orange juice, a cola-based soft drink, and a 10% sucrose solution (negative control were tested. These drinks differ in terms of their pH (3.5 ± 0.04, 2.5 ± 0.05, and 5.9 ± 0.1, respectively and titratable acidity (3.17 ± 0.06, 0.57 ± 0.04 and < 0.005 mmols OH- to reach pH 5.5, respectively. Eight volunteers with a normal salivary flow rate and buffering capacity kept 15 mL of each beverage in their mouth for 10 s, expectorated it, and their saliva was collected after 15, 30, 45, 60, 90, and 120 s. The salivary pH, determined using a mini pH electrode, returned to the baseline value at 30 s after expectoration of the cola-based soft drink, but only at 90 s after expectoration of the orange juice. The salivary pH increased to greater than 5.5 at 15 s after expectoration of the cola drink and at 30 s after expectoration of the orange juice. These findings suggest that the titratable acidity of a beverage influences salivary pH values after drinking acidic beverages more than the beverage pH.

  20. Critical assessment of the pH of children's soap

    Directory of Open Access Journals (Sweden)

    Bruna Rafaela Mendes

    2016-06-01

    Full Text Available Abstract Objective: To evaluate the pH value of children's antibacterial soaps and syndets used in children's baths and verify whether there is information regarding pH on the product label. Methods: Quantitative, cross-sectional, analytical observational study that included ninety soap samples, both in bar and liquid presentations, as follows: 67 children's soap (group 1, 17 antibacterial soaps (group 2, and 6 syndets (group 3. Each sample had its pH measured after 1% dilution. In addition to descriptive statistics, the Pearson-Yates chi-squared test and Student's t-tests were applied, considering the minimal significance level of 5%. The Wilcoxon-Mann-Whitney test, Fisher's exact test, and the Kruskal-Wallis test were used for inferential statistics. Results: The pH levels varied considerably between liquid and bar presentations, with lower levels (4.4-7.9 found for the liquids (p < 0.05. Syndets showed pH levels close to the ideal (slightly acid and the antibacterial soaps showed the highest pH levels (up to 11.34 (p < 0.05. Only two of the soaps included in the study had information about their pH levels on the product packaging. Conclusions: Knowledge of the pH of children's soap by doctors and users is important, considering the great pH variability found in this study. Moreover, liquid soaps, and especially syndets, are the most recommended for the sensitive skin of neonates and infants, in order to guarantee skin barrier efficacy.

  1. Effect of AlN Particulate Size on Superplasticity of AlNp/6061 Al Composites

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Superplastic tensile tests of AlNp/606l Al Composites, fabricated by powder metallurgy techniques, were performed at strain rates ranging from 10-1-10-3S-1 and at temperatures from 833 to 893 K. Hot rolling after extrusion was employed to obtain a fine grained structure before \\superplastic testing. The superplastic behavior of AlNp/6061 Al Composites was compared with that of AlN particulate size. Differential scanning calorimeter was used to ascertain the possibility of any partial melting in the vicinity of optimum superplastic temperatures.

  2. Optic nerve pH and PO2

    DEFF Research Database (Denmark)

    Pedersen, Daniella B; Stefánsson, Einar; Kiilgaard, Jens Folke;

    2006-01-01

    Earlier studies have demonstrated that carbonic anhydrase inhibitors (CAIs) increase optic nerve oxygen tension (ONPO(2)) in pigs. We hypothesized that the mechanism of this effect was either a CO(2) increase or a pH decrease in tissue and blood. To test this hypothesis we investigated and compared...... how optic nerve pH (ONpH) and ONPO(2) are affected by: (1) carbonic anhydrase inhibition; (2) respiratory acidosis, and (3) metabolic acidosis. We measured ONpH with a glass pH electrode and ONPO(2) with a polarographic oxygen electrode. One of the electrodes was placed in the vitreous cavity 0.5 mm...

  3. A survey of beef muscle color and pH.

    Science.gov (United States)

    Page, J K; Wulf, D M; Schwotzer, T R

    2001-03-01

    The objectives of this study were to define a beef carcass population in terms of muscle color, ultimate pH, and electrical impedance; to determine the relationships among color, pH, and impedance and with other carcasses characteristics; and to determine the effect of packing plant, breed type, and sex class on these variables. One thousand beef carcasses were selected at three packing plants to match the breed type, sex class, marbling score, dark-cutting discount, overall maturity, carcass weight, and yield grade distributions reported for the U.S. beef carcass population by the 1995 National Beef Quality Audit. Data collected on these carcasses included USDA quality and yield grade data and measurements of muscle color (L*, a*, b*), muscle pH, and electrical impedance of the longissimus muscle. About one-half (53.1%) of the carcasses fell within a muscle pH range of 5.40 to 5.49, and 81.3% of the carcasses fell within a longissimus muscle pH range of 5.40 to 5.59. A longissimus muscle pH of 5.87 was the approximate cut-off between normal and dark-cutting carcasses. Frequency distributions indicated that L* values were normally distributed, whereas a* and b* values were abnormally distributed (skewed because of a longer tail for lower values, a tail corresponding with dark-cutting carcasses). Electrical impedance was highly variable among carcasses but was not highly related to any other variable measured. Color measurements (L*, a*, b*) were correlated (P carcasses had higher muscle pH values and lower colorimeter readings. Steer carcasses (L* = 39.62, a* = 25.20, and b* = 11.03) had slightly higher colorimeter readings (P carcasses (L* = 39.20, a* = 24.78, and b* = 10.80) even though muscle pH was not different between steer and heifer carcasses. Dairy-type carcasses (pH = 5.59, L* = 37.56, a* = 23.40, and b* = 9.68) had higher muscle pH values and lower colorimeter readings than either native-type (pH = 5.50, L* = 39.55, a* = 25.13, and b* = 11.00) or Brahman

  4. Wound pH depends on actual wound size

    CERN Document Server

    Sirkka, T; Apell, S P

    2016-01-01

    Wound healing is an intricate process that involves many types of cells, reaction pathways as well as chemical, physical and electrical cues. Since biochemical reactions and physiological events are pH-dependent we study here pH as an important major characteristic of the wound healing process in the presence of endogenous and exogenous electric fields. Our model gives the spatial pH distribution in a wound. In particular we isolate a number of dimensionless quantities which sets the length, energy and time scales governing the wound healing process and which can be experimentally tested. Most interesting finding is that wound pH depends on actual wound size.

  5. Microscale pH regulation by splitting water

    OpenAIRE

    Cheng, Li-Jing; Chang, Hsueh-Chia

    2011-01-01

    We present a simple, flexible approach for pH regulation in micro-chambers by injecting controllable amounts of protons and hydroxide ions via field-enhanced dissociation of water molecules. Under a DC voltage bias, the polymeric bipolar membranes integrated in microfluidics devices generate and separate H+ and OH− ions without gas production or contaminant generation resulting from electron-transfer reactions. Robust local on-chip pH and pH gradients are sustained with no need of additional ...

  6. Differential pH sensitivity of tissue superoxide dismutases

    OpenAIRE

    Patel, Samir P.; Katyare, Surendra S.

    2006-01-01

    Superoxide dismutase (SOD) activities in the human and rat RBCs and rat liver, kidney, brain and heart mitochondria as well as cytosolic fractions were determined by the pyrogallol assay procedure with slight modifications. Measurements were carried out in 0.1 M potassium phosphate buffer pH 8.0 and 9.2 to assess the pH stability of the SODs from various systems. Under these conditions the SODs from different systems including RBCs exhibited differential pH stability i.e. they displayed diffe...

  7. eLectures – Lehrkräftefortbildung der Zukunft - Erfahrungsbericht über mehr als 1 Jahr synchrones e-Learning

    Directory of Open Access Journals (Sweden)

    Alfred Peherstorfer

    2011-09-01

    Full Text Available Seit mehr als einem Jahr wird seitens der Virtuellen PH auf der Live Online Plattform Adobe Connect Weiterbildung für Lehrkräfte angeboten: eLectures. Hier ein Erfahrungsbericht.

  8. Role of Metal Cations on the corrosion behaviour of 8090-T851 in a pH 2.0 solution

    DEFF Research Database (Denmark)

    Murthy, K.S.N.; Ambat, Rajan; Dwarakadasa, E.S.

    1994-01-01

    The influence of cations such as Cu2+, Al3+ and Li+ on the corrosion behaviour of 8090-T851(Al-Li) alloy in a pH 2.0 HCl solution was investigated by weight loss and polarisation techniques. Weight loss experiments showed that the effect of cation is a strong function of its nature and concentrat...... indicated that the corrosion activation by Al3+ ions is due to their chemical reactivity with the corroding substrate. Little enhancement in corrosion by Li+ ions is attributed to the increase in solution conductivity in their presence....

  9. Editorial: Cartas al Editor

    Directory of Open Access Journals (Sweden)

    Guillermo Llanos

    2006-06-01

    Full Text Available En todas las revistas biomédicas del mundo existe una sección habitual denominada como el título de este editorial y que en Colombia Médica la llamamos correspondencia. Este espacio tiene como objetivo fundamental que los lectores escriban a los autores (investigadores comentando los artículos que se han publicado en números anteriores de la revista. Las cartas son, entonces, breves comentarios de desacuerdo o acuerdo (conceptual, metodológico, interpretativo sobre falencias ubicadas por un lector alerta al tema debatido en cualquiera de las secciones como en los artículos originales, editoriales, revisiones, presentación de casos, etc. publicados previamente en la revista. Las cartas deben permitir el intercambio de opiniones y formas de pensar y analizar los problemas planteados entre los autores y los lectores. En ocasiones una serie de cartas motivadas por un artículo original puede ser tan o más interesante como el artículo que generó la correspondencia. Las cartas son también un formato adecuado para comunicar un hecho novedoso de una observación clínica juiciosa no descrita antes. Un ejemplo de ello es la carta de un gineco-obstetra australiano cuando informó a Lancet los primeros efectos adversos informados de la talidomida. Colombia Médica, a pesar de mantener vigente esta sección, no ha sido muy afortunada en establecer una buena cultura del envío de cartas al editor. Pero últimamente han llegado juiciosas observaciones a las cuales se les ha dado prioridad en su publicación. Toda carta que comenta los hallazgos de un artículo es enviada a los autores para su respuesta, porque ello genera el debate académico buscado, y luego se publican, tanto la carta como su respuesta. El Estilo Vancouver recomienda que la carta y su respuesta deban ser breve, no pasar de dos o tres párrafos y contener sólo cuatro o cinco referencias. En lo posible (a menos que sea indispensable no presentar ni cuadros ni gráficos. El t

  10. Malamih al-Ashwat al-'Arabiyyah wa Makharijaha

    Directory of Open Access Journals (Sweden)

    Amrah Muhammad Kasim

    2015-12-01

    Full Text Available This writing discusses on al-ashwat al-‘arabiyyah that is known with “phonetic” term. It talks and interprets makharij al-huruf or place for producing sounds and also processing production of sounds by parts of mouth in Arabic language. The problems of sounds and its systems in Arabic language have been conducted by the scholars of al-ashwat al-‘arabiyyah attractively, neatly, and detail and gotten ahead the phonetic western scholars. Part of their analysis results formulate the study about al-ashwat al-sakinah (al-Shamit is known with vocal and consonant sounds in research questions shawait – shawamit. Ibnu Jinni has formulated “harakat”(wowel in Arabic language and dimension of letter  mad and liyn on alif  letter - waw - ya’ (ا و ي, from these letters create  harakat fathah, dammah, and kasrah. Moreover, in this writing also exist the description of hija’i letters and its makhraj that are correct from parts of mouth and the unity of coordinative sounds that produce sounds in morphemes arrangement, in one word that produces meaning. The result of phonological study has divided al-ashwat to be kinds of sound like the pronounced sounds, produced sounds from mouth, and heard sound.

  11. Capacidade tamponante, pH e consistência das fezes em equinos submetidos à sobrecarga dietética com amido Buffer capacity, pH and faeces consistency in horses submitted to dietetic starch overload

    Directory of Open Access Journals (Sweden)

    Tiago Marques dos Santos

    2009-09-01

    Full Text Available Este trabalho teve como objetivo avaliar a capacidade tamponante (CT, o pH e a consistência das fezes em equinos submetidos à sobrecarga dietética com amido. Seis equinos adultos foram submetidos à sobrecarga com infusão gástrica de 17,6g de amido kg-1 de peso corporal através de sonda nasogástrica. Amostras fecais foram coletadas, antes e quatro, oito, 12, 16, 20, 24, 28, 32 e 36 horas pós-sobrecarga, e imediatamente submetidas à avaliação do pH, da CT e da consistência. Os resultados de pH foram comparados pelo teste t de student (P0,05 no pH fecal ao longo de 36 horas pós-sobrecarga, com valores médios variando de 6,09 a 4,46. A partir do modelo pH = 6,083 - 0,003t - 0,001t² (R² = 0,634, houve decréscimo de 0,004 no pH fecal a cada hora, de 0,028 a cada quatro horas e de 1,404 ao final de 36 horas após a sobrecarga, respectivamente. Além do pH, houve redução (PThis study aimed to evaluate buffer capacity (BC, pH and faeces consistency of horses submitted to dietetic starch overload. Six crossbreed mature horses were submitted to starch overload with gastric infusion of 17.6g starch kg-1 body weight through nasogastric tube. Faecal samples were collected, before and at 4, 8, 12, 16, 20, 24, 28, 32 and 36 hours post-overload, and immediately submitted to evaluation of pH, BC and consistency. The pH data were compared by t student test (P0.05, with means values varying from 6.09 to 4.46. Based on the model pH = 6.083 - 0.003t - 0.001t² (R² = 0.634, faecal pH decreased 0.004 per hour, 0.028 to each four hours and 1.404 at 36 hours after overload, respectively. As pH, faeces BC decreased (P<0.05 in function of the time after overload. Positive relationship was observed (r = 0.65; P<0.0001 between pH and BC of faeces. All horses presented normal consistency faeces (score 3 until eight hours after overload, following by reduction (P<0.05 up to 36 hours. Results demonstrated that starch overload reduce faecal consistency

  12. Label-Free Carbon-Dots-Based Ratiometric Fluorescence pH Nanoprobes for Intracellular pH Sensing.

    Science.gov (United States)

    Shangguan, Jingfang; He, Dinggeng; He, Xiaoxiao; Wang, Kemin; Xu, Fengzhou; Liu, Jinquan; Tang, Jinlu; Yang, Xue; Huang, Jin

    2016-08-01

    Measuring pH in living cells is of great importance for better understanding cellular functions as well as providing pivotal assistance for early diagnosis of diseases. In this work, we report the first use of a novel kind of label-free carbon dots for intracellular ratiometric fluorescence pH sensing. By simple one-pot hydrothermal treatment of citric acid and basic fuchsin, the carbon dots showing dual emission bands at 475 and 545 nm under single-wavelength excitation were synthesized. It is demonstrated that the fluorescence intensities of the as-synthesized carbon dots at the two emissions are pH-sensitive simultaneously. The intensity ratio (I475 nm/I545 nm) is linear against pH values from 5.2 to 8.8 in buffer solution, affording the capability as ratiometric probes for intracellular pH sensing. It also displays that the carbon dots show excellent reversibility and photostability in pH measurements. With this nanoprobe, quantitative fluorescence imaging using the ratio of two emissions (I475 nm/I545 nm) for the detection of intracellular pH were successfully applied in HeLa cells. In contrast to most of the reported nanomaterials-based ratiometric pH sensors which rely on the attachment of additional dyes, these carbon-dots-based ratiometric probes are low in toxicity, easy to synthesize, and free from labels. PMID:27334762

  13. AL-IZDIWAJIYYAH AL-LUGHOWIYAH FII ISTIHDHAMI AL-LUGHOH AL-‘ARABIYAH

    Directory of Open Access Journals (Sweden)

    Imam Muslimin

    2011-10-01

    Full Text Available Al-Izdiwajiyyah (diglosia is standardizing a specific language when there are two variants of language that live side by side in societal life and each variant has its own social function. Disglosia is related to the use of local languages variations of low language and high language in a community. In Arabic language, disglosia covers dialects among the speakers, for instance there are two variants of language that each has roles and functions. The use of the variant depends on the situation. The most important characteristic of diglosia is specifying the functions of wach language variant. For high level language variant is aimed for formal situations such as religious ceremony, lectures, news, or editorials of newspaper. On the contrary, the low level language variant is commonly used in less formal situation such as daily communication in the family, chat with friends, stories in radion, and folk literature. In Arabic language, diglosia can be identified when the speaker of the language use diction commonly used for daily communication (amiyah in a formal expression (fusha, and vice versa.

  14. Controlling pH in a Precipitation Plant

    Directory of Open Access Journals (Sweden)

    Kjell Støle-Hansen

    1997-10-01

    Full Text Available This paper deals with pH control in a precipitation and dissolution process. The process is a part of the electrolyte purification plant at Falconbridge Nikkelverk in Kristiansand, Norway. The process including the present strategy for pH control are presented, and experienced weaknesses with this strategy are described. A rigorous dynamic model of the process is briefly summarized. This model was developed in earlier work with the purpose of being a tool for control design. Because of the precipitation in form of hydroxides and the limited dissolution rate of nickel carbonate, the process is approximately linear in pH. Therefore, an alternative strategy for pH control based on adding derivative and feed forward action is suggested. The alternative control strategy is by simulations shown to give severe improvements in performance. The robustness of the proposed controller is briefly analysed.

  15. Commentary: PhDs in Biochemistry Education--5 Years Later

    Science.gov (United States)

    Offerdahl, Erika G.; Momsen, Jennifer L.; Osgood, Marcy

    2014-01-01

    In this commentary, the discussion of PhDs in biochemistry education research is expanded to explore a number of diverse pathways leading to a competitive research program in biochemistry education research.

  16. Commentary: PhDs in biochemistry education-5 years later.

    Science.gov (United States)

    Offerdahl, Erika G; Momsen, Jennifer L; Osgood, Marcy

    2014-01-01

    In this commentary, the discussion of PhDs in biochemistry education research is expanded to explore a number of diverse pathways leading to a competitive research program in biochemistry education research.

  17. The Training and Work of Ph.D. Physical Scientists

    Science.gov (United States)

    Smith, S. J.; Schweitzer, A. E.

    2003-05-01

    Doctoral education has often been viewed as the pinnacle of the formal education system. How useful is doctoral training in one's later career? In an NSF-funded project, we set out to perform a study of the training, careers, and work activities of Ph.D. physical scientists. The study included both in-depth interviews and a survey sent out to a sample of Ph.D. holders 4-8 years after graduation. Come and find out the results of this study: What skills are most Ph.D. physical scientists using? What should graduate programs be teaching? Are Ph.D.'s who are working in their specific field of training happier than their counterparts working different jobs? What skills and preparation lead to future job satisfaction, perhaps the most important indicator of the "success" of graduate education? A preprint and further details can be found at the project web site at: spot.colorado.edu/ phdcarer.

  18. Effect of environmental pH on sperm kinematic characteristics

    DEFF Research Database (Denmark)

    Alipour, Hiva; Dardmeh, Fereshteh; Dissing, Marianne Charlotte;

    2015-01-01

    differences in the details of the sperm movement (kinematics) of human sperm provided by computerized sperm analysis systems. This study was designed to assess the effect of two different media pH levels on kinematic parameters of the human sperm. Samples were prepared using the 40%/80% Pureception (Sage, USA......) density gradient and resuspended in customized sperm culture media with pH levels of 7.9 and 8.3 (Origio, Denmark). Kinematic parameters of the sperm in both groups were analyzed using the Sperm Class Analyzer (Microptic S.L., Spain) at 0, 6 and 24 hours following the addition of media. Results....... Linearity and Wobble showed significant difference after 24 hours. This study demonstrated a difference in the sperm motion pattern and velocity in different environmental pH levels. Based on these findings, further investigations are required to elucidate knowledge about possible effect of marginal pH...

  19. The bimodal pH distribution of volcanic lake waters

    Science.gov (United States)

    Marini, Luigi; Vetuschi Zuccolini, Marino; Saldi, Giuseppe

    2003-02-01

    Volcanic lake waters have a bimodal pH distribution with an acidic mode at pH 0.5-1.5 and a near neutral mode at pH 6-6.5, with relatively few samples having pH 3.5-5. To investigate the reasons for this distribution, the irreversible water-rock mass exchanges during the neutralization of acid SO 4-Cl waters with andesite, under both low- and high-temperature conditions, were simulated by means of the EQ3/6 software package, version 7.2. Reaction path modeling under low temperature and atmospheric P CO 2 and f O 2, suggests that several homogeneous and/or heterogeneous pH buffers exist both in the acidic and neutral regions, but no buffer is active in the intermediate, central pH region. Again, the same titration, under high-temperature, hydrothermal-magmatic conditions, is expected to produce comparatively infrequent aqueous solutions with pH values in the 3.5-5 range, upon their cooling below 100°C. Substantially different pH values are obtained depending on the cooling paths, either through boiling or conductive heat losses. These distinct pH values are governed by either HSO 4- and HCl (aq), in poorly neutralized aqueous solutions, or the CO 2(aq)/HCO 3- couple and the P CO 2 value as well, in neutralized aqueous solutions. Finally, mixing of the acid lake water with the aqueous solutions produced through high-temperature titration and cooled below 100°C is unlikely to generate mixtures with pH values higher than 3, unless the fraction of the acidic water originally present in the lake becomes very small, which means its virtually complete substitution. Summing up, the evidence gathered through reaction path modeling of the neutralization of acid lake waters with andesite, both at low and high temperatures, explains the scarcity of volcanic lake waters with measured pH values of 3.5-5.

  20. Efeito da salinidade e do esgoto orgânico sobre a comunidade zooplanctônica, com ênfase nos copépodes, do estuário do rio Itanhaém, Estado de São Paulo - DOI: 10.4025/actascibiolsci.v26i1.1652 Effects of salinity and organic wastes on zooplancton community, with emphasis on copepodes, in the Itanhaém river estuary, São Paulo state - DOI: 10.4025/actascibiolsci.v26i1.1652

    Directory of Open Access Journals (Sweden)

    Antonio Fernando Monteiro Camargo

    2004-04-01

    Full Text Available A partir da hipótese de que a comunidade zooplanctônica é influenciada pela salinidade e pelo lançamento de esgotos orgânicos, o objetivo deste trabalho é analisar a influência desses fatores sobre essa comunidade no estuário do rio Itanhaém, Estado de São Paulo. Foram realizadas amostragens do zooplâncton e de variáveis físicas e químicas da água em quatro estações de coleta, localizadas entre a linha de costa e a parte superior do estuário, incluindo um canal secundário que recebe esgotos domésticos sem tratamento prévio. As amostragens foram realizadas em baixa-mar e preamar no inverno e verão. Os resultados mostraram que este estuário possui uma variação temporal de características físicas e químicas, especialmente salinidade, devido à variação de marés e à variação sazonal de pluviosidade. Os maiores valores de salinidade foram observados no inverno e preamar. A comunidade zooplanctônica respondeu às variações de salinidade, com espécies adaptadas aos maiores valores de salinidade na parte baixa do estuário, no inverno. Embora o estuário do rio Itanhaém possua a mesma dinâmica temporal e espacial de outros estuários, os valores de salinidade são bastante reduzidos em comparação com outros estuários da costa sul paulista. Em conseqüência, a comunidade zooplanctônica foi constituída principalmente por organismos oligoalinos e de água doce. Essas características se devem à maior área de drenagem da bacia do rio Itanhaém quando comparada com a área dos outros rios costeiros do Estado de São Paulo. O esgoto orgânico modificou as características físicas e químicas da água, que possuiu maior concentração de nutrientes, maior quantidade de material em suspensão e menor concentração de oxigênio. Foi observada uma relação positiva entre densidade de náuplios de copépodes e poluição orgânica no estuário do rio ItanhaémThe objective of this work is to analyze the effects of

  1. Information behaviour and practices of PhD students

    OpenAIRE

    Drachen, Thea Marie; Larsen, Asger Væring; Gullbekk, Eystein; Westbye, Hilde; Lach, Karin

    2011-01-01

    This report addresses the information behaviour and practices of PhD students and its implications for library services. Academic libraries and their services are part of the information network of PhD students. Therefore libraries should pay special attention to the needs and practices of this important academic subgroup. The University Librarian at Copenhagen University Library and Information Service (CULIS) commissioned this study. It was conducted by representatives from CULIS, Universit...

  2. Seawater pH and Anthropogenic Carbon Dioxide

    CERN Document Server

    Marsh, Gerald E

    2008-01-01

    In 2005, the Royal Society published a report titled "Ocean acidification due to increasing atmospheric carbon dioxide". The report's principal conclusion-that average ocean pH could decrease by 0.5 units by 2100-is demonstrated here to be consistent with a linear extrapolation of very limited data. It is also shown that current understanding of ocean mixing, and of the relationship between pH and atmospheric carbon dioxide concentration, cannot justify such an extrapolation.

  3. The PhD in Writing Accompanied by an Exegesis

    Science.gov (United States)

    Arnold, Josie

    2005-01-01

    The position of this paper is to further the discussion on what constitutes academic assessment in the PhD by artefact and exegesis. In doing so, it explores some of the ideas that arose in setting up the PhD in creative writing at Swinburne University of Technology. Thus, I: (1) survey some of the questions that arise about the journeys made by…

  4. Teaching Human Digestion and pH Using Technology

    Science.gov (United States)

    Kim, Hanna

    2008-01-01

    Testing the pH of various liquids is one of the most popular activities in 5th- through 8th-grade classrooms. The author presents an extensive pH-testing lesson based on a 5E (engagement, exploration, explanation, extension, and evaluation) teaching model. The activity provides students with the opportunity to learn about pH and how it relates to…

  5. Transport mechanism of a glutamate transporter homologue GltPh

    Science.gov (United States)

    Ji, Yurui; Postis, Vincent L.G.; Wang, Yingying; Bartlam, Mark; Goldman, Adrian

    2016-01-01

    Glutamate transporters are responsible for uptake of the neurotransmitter glutamate in mammalian central nervous systems. Their archaeal homologue GltPh, an aspartate transporter isolated from Pyrococcus horikoshii, has been the focus of extensive studies through crystallography, MD simulations and single-molecule FRET (smFRET). Here, we summarize the recent research progress on GltPh, in the hope of gaining some insights into the transport mechanism of this aspartate transporter. PMID:27284058

  6. Glucosylceramide modulates endolysosomal pH in Gaucher disease.

    Science.gov (United States)

    Sillence, Dan J

    2013-06-01

    GlcCer accumulation causes Gaucher disease where GlcCer breakdown is inhibited due to a hereditary deficiency in glucocerebrosidase. Glycolipids are endocytosed and targeted to the Golgi apparatus in normal cells but in Gaucher disease they are mistargeted to lysosomes. To better understand the role of GlcCer in endocytic sorting RAW macrophages were treated with Conduritol B-epoxide to inhibit GlcCer breakdown. Lipid analysis found increases in GlcCer led to accumulation of both triacylglycerol and cholesterol consistent with increased lysosomal pH. Ratio imaging of macrophages using both acridine orange and lysosensor yellow/blue to measure endolysosomal pH revealed increases in Conduritol B-epoxide treated RAW macrophages and Gaucher patient lymphoblasts. Increased endolysosomal pH was restricted to Gaucher lymphoblasts as no significant increases in pH were seen in Fabry, Krabbe, Tay-Sachs and GM1-gangliosidosis lymphoblasts. Substrate reduction therapy utilises inhibitors of GlcCer synthase to reduce storage in Gaucher disease. The addition of inhibitors of GlcCer synthesis to RAW macrophages also led to increases in cholesterol and triacylglycerol and an endolysosomal pH increase of up to 1 pH unit. GlcCer modulation appears specific since glucosylsphingosine but not galactosylsphingosine reversed the effects of GlcCer depletion. Although no acute effects on glycolipid trafficking were observed using bafilomycin A the results are consistent with a multistep model whereby increases in pH lead to altered trafficking via cholesterol accumulation. GlcCer modulates endolysosomal pH in lymphocytes suggesting an important role in normal lysosomes which may be disrupted in Gaucher disease. PMID:23628459

  7. Urea sensors based on PVC membrane pH electrode.

    Science.gov (United States)

    Głab, S; Koncki, R; Kopczewska, E; Wałcerz, I; Hulanicki, A

    1994-07-01

    Several procedures of urease immobilization on the surface of the polymeric membrane pH electrode with tri-n-dodecylamine as a neutral carrier were compared. The best results were obtained for the urea sensor with covalently bound urease. The sensor characteristics including the effect of buffer, pH and concentration and the effect of stirring rate are presented. These effects are in good agreement with theoretical expectations.

  8. Economical wireless optical ratiometric pH sensor

    Science.gov (United States)

    Vuppu, Sandeep; Kostov, Yordan; Rao, Govind

    2009-04-01

    The development and application of a portable, wireless fluorescence-based optical pH sensor is presented. The design incorporates the MSP430 microcontroller as the control unit, an RF transceiver for wireless communication, digital filters and amplifiers and a USB-based communication module for data transmission. The pH sensor is based on ratiometric fluorescence detection from pH sensitive dye incorporated in a peel-and-stick patch. The ability of the instrument to detect the pH of the solution with contact only between the sensor patch and the solution makes it partially non-invasive. The instrument also has the ability to transmit data wirelessly, enabling its use in processes that entail stringent temperature control and sterility. The use of the microcontroller makes it a reliable, low-cost and low-power device. The luminous intensity of the light source can be digitally controlled to maximize the sensitivity of the instrument. It has a resolution of 0.05 pH. The sensor is accurate and reversible over the pH range of 6.5-9.

  9. Structure of human saposin A at lysosomal pH

    Energy Technology Data Exchange (ETDEWEB)

    Hill, Chris H.; Read, Randy J.; Deane, Janet E., E-mail: jed55@cam.ac.uk [University of Cambridge, Wellcome Trust/MRC Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY (United Kingdom)

    2015-06-27

    A 1.8 Å resolution structure of the sphingolipid activator protein saposin A has been determined at pH 4.8, the physiologically relevant lysosomal pH for hydrolase enzyme activation and lipid-transfer activity. The saposins are essential cofactors for the normal lysosomal degradation of complex glycosphingolipids by acid hydrolase enzymes; defects in either saposin or hydrolase function lead to severe metabolic diseases. Saposin A (SapA) activates the enzyme β-galactocerebrosidase (GALC), which catalyzes the breakdown of β-d-galactocerebroside, the principal lipid component of myelin. SapA is known to bind lipids and detergents in a pH-dependent manner; this is accompanied by a striking transition from a ‘closed’ to an ‘open’ conformation. However, previous structures were determined at non-lysosomal pH. This work describes a 1.8 Å resolution X-ray crystal structure determined at the physiologically relevant lysosomal pH 4.8. In the absence of lipid or detergent at pH 4.8, SapA is observeed to adopt a conformation closely resembling the previously determined ‘closed’ conformation, showing that pH alone is not sufficient for the transition to the ‘open’ conformation. Structural alignments reveal small conformational changes, highlighting regions of flexibility.

  10. Economical wireless optical ratiometric pH sensor

    International Nuclear Information System (INIS)

    The development and application of a portable, wireless fluorescence-based optical pH sensor is presented. The design incorporates the MSP430 microcontroller as the control unit, an RF transceiver for wireless communication, digital filters and amplifiers and a USB-based communication module for data transmission. The pH sensor is based on ratiometric fluorescence detection from pH sensitive dye incorporated in a peel-and-stick patch. The ability of the instrument to detect the pH of the solution with contact only between the sensor patch and the solution makes it partially non-invasive. The instrument also has the ability to transmit data wirelessly, enabling its use in processes that entail stringent temperature control and sterility. The use of the microcontroller makes it a reliable, low-cost and low-power device. The luminous intensity of the light source can be digitally controlled to maximize the sensitivity of the instrument. It has a resolution of 0.05 pH. The sensor is accurate and reversible over the pH range of 6.5–9

  11. pH sensing by intracellular Salmonella induces effector translocation.

    Science.gov (United States)

    Yu, Xiu-Jun; McGourty, Kieran; Liu, Mei; Unsworth, Kate E; Holden, David W

    2010-05-21

    Salmonella enterica is an important intracellular bacterial pathogen of humans and animals. It replicates within host-cell vacuoles by delivering virulence (effector) proteins through a vacuolar membrane pore made by the Salmonella pathogenicity island 2 (SPI-2) type III secretion system (T3SS). T3SS assembly follows vacuole acidification, but when bacteria are grown at low pH, effector secretion is negligible. We found that effector secretion was activated at low pH from mutant strains lacking a complex of SPI-2-encoded proteins SsaM, SpiC, and SsaL. Exposure of wild-type bacteria to pH 7.2 after growth at pH 5.0 caused dissociation and degradation of SsaM/SpiC/SsaL complexes and effector secretion. In infected cells, loss of the pH 7.2 signal through acidification of host-cell cytosol prevented complex degradation and effector translocation. Thus, intravacuolar Salmonella senses host cytosolic pH, resulting in the degradation of regulatory complex proteins and effector translocation. PMID:20395475

  12. Vacuolation induced by unfavorable pH in cyanobacteria

    Institute of Scientific and Technical Information of China (English)

    赵以军; 吴红艳; 郭厚良; 许敏; 程凯; 祝海燕

    2001-01-01

    Six species or strains of cyanobacteria, Anabaena sp. 595, Plectonema boryanum 246, Scytonema hofmanni 248, Nostoc sp. 96, Oscillatoria animlis 284 and Spirulina maxima 438, were cultured in unfavorable pH conditions for vacuole induction. At pH 5.0, 6.5, or 7.0, vacuoles were observed to form in both Anabaena sp. 595 and Plectonema boryanum 246, especially in the former. The vacuolation took place with some morphological changes, such as the cells being inflated, spherical and vacuolated, and with unequalized division. The induced vacuoles in An- abaena sp. 595 and Plectonema boryanum 246 were in spherical shape and in rather transparent appearance under a phase microscope. For Scytonema hofmanni 248, it was less sensitive to pH, its vacuole formation was found only at pH 6.5. No vacuolization occurred in the cells of Nostoc sp. 96, Oscillatoria animlis 284 and Spirulina maxima 438 at all pH conditions we used. Vacuolization under unfavorable pH provides a new proof for the existence of vacuole in cells of cyanobacteria and reflects the prokaryote's function in ecological environment.

  13. Al versus Si competition in FeSiAl alloys

    Energy Technology Data Exchange (ETDEWEB)

    Legarra, E. [Dpto. Electricidad y Electronica, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco (UPV/EHU), CP 644, 48080 Bilbao (Spain)], E-mail: estibaliz.legarra@ehu.es; Apinaniz, E. [Dpto. Fisica Aplicada I, Escuela de Ingenieria Tecnica Superior, Universidad del Pais Vasco, Alameda de Urquijo s/n 48013 Bilbao (Spain); Plazaola, F. [Dpto. Electricidad y Electronica, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco (UPV/EHU), CP 644, 48080 Bilbao (Spain); Jimenez, J.A. [Centro Nacional de Investigaciones Metalurgicas (CENIM), Avda. Gregorio del amo 8, 28040 Madrid (Spain); Pierna, A.R. [Chemical Engineering and Environmental Department, UPV/EHU, Box 1379, 20008 San Sebastian (Spain)

    2008-10-15

    In FeSiAl alloys, when Si substitutes for Al, important changes take place in the magnetism as well as in the structural properties. Alloys in the two composition series Fe{sub 75}Al{sub 25-x}Si{sub x} (x=0, 7.5, 12.5, 17.5, 25) and Fe{sub 70}Al{sub 30-x}Si{sub x} (x=0, 9, 15, 21, 30) were prepared by induction melting; afterwards they were crushed and then annealed in order to recover the DO{sub 3} stable phase. The deformed FeAl samples show larger lattice parameters than the ordered ones; however, this difference ({delta}a) decreases when Si substitutes for Al until it becomes zero (i.e. until the ordered samples and the deformed ones have the same lattice parameters). This trend is the same for both sample series and does not depend on the Fe content of the alloy. However, the magnetization has a different behaviour depending on the Fe content. For deformed Fe{sub 75}Al{sub 25-x}Si{sub x} alloys the saturation magnetization decreases with increasing Si content while for Fe{sub 70}Al{sub 30-x}Si{sub x} deformed alloys the saturation magnetization has a plateau in which the saturation magnetization values do not vary.

  14. Undulators at the ALS

    International Nuclear Information System (INIS)

    At Lawrence Berkeley Laboratory's (LBL) Advanced Light Source (ALS), three 4.6 m long undulators have been completed, tested and installed. A fourth is under construction. The completed undulators include two 5.0 cm period length, 89 period devices (U5.0s) which achieve a 0.85 T effective field at a 14 mm minimum gap and a 8.0 cm period length, 55 period device (U8.0) that reaches a 1.2 T effective field at a 14 mm minimum gap. The undulator under construction is a 10.0 cm period length, 43 period device (U10.0) that is designed to achieve 0.98 T at a 23 mm gap. Undulator magnetic gap variation (rms) is within 25 microns over the periodic structure length. Reproducibility of the adjustable magnetic gap has been measured to be within +/- 5 microns. Gap adjusting range is from 14 mm to 210 mm, which can be scanned in one minute. The 5.1 m long vacuum chambers are flat in the vertical direction to within 0.74 mm and straight in the horizontal direction to within 0.08 mm over the 4.6 m magnetic structure sections. Vacuum chamber base pressures after UHV beam conditioning are. in the mid 10-11 Torr range and storage ring operating pressures with full current are in the low 10-10 Torr range. Measurements show that the uncorrelated magnetic field errors are 0.23%, and 0.20% for the two U5.Os and the U8.0 respectively and that the field integrals are small over the 1 cm by 6 cm beam aperture. Device description, fabrication, and measurements are presented

  15. Alexandria (Al Iskandariya), Egypt

    Science.gov (United States)

    2002-01-01

    This image of Alexandria was taken by astronauts on board the International Space Station in December 2000 using an Electronic Still Camera. A wider-angle view (STS088-739-90) taken from the Space Shuttle in December 1998 is available for context. Alexandria (Al Iskandariya) occupies a T-shaped peninsula and strip of land separating the Mediterranean from Lake Mariout. Originally the town was built upon a mole (stone breakwater) called Heptastadium, which joined the island of Pharos (see referenced website, below) to the mainland. Since then sedimentary deposits have widened the mole. Since 1905, when the 370,000 Alexandrians lived in an area of about 4 sq km between the two harbors, the city (population 4 million; see referenced website, below) has grown beyond its medieval walls and now occupies an area of about 300 sq km. The Mahmudiya Canal, connecting Alexandria with the Nile, runs to the south of the city and, by a series of locks, enters the harbor of the principal port of Egypt (note ships). The reddish and ochre polygons west of Lake Mariout are salt-evaporation, chemical-storage, and water-treatment ponds within the coastal lagoon. Reference Youssef Halim and Fatma Abou Shouk, 2000, Human impacts on Alexandria's marine environment: UNESCO, Coastal Regions and Small Islands Unit (CSI), Coastal Management Sourcebooks 2 (accessed December 20, 2000) Additional photographs taken by astronauts can be viewed at NASA-JSC's Gateway to Astronaut Photography of Earth. Image ISS001-ESC-5025 provided by the Earth Sciences and Image Analysis Laboratory, Johnson Space Center.

  16. Groundwater chemistry of Al under Dutch sandy soils: Effects of land use and depth

    NARCIS (Netherlands)

    Fest, E.P.M.J.; Temminghoff, E.J.M.; Griffioen, J.; Grift, B. van der; Riemsdijk, W.H. van

    2007-01-01

    Aluminium has received great attention in the second half of the 20th century, mainly in the context of the acid rain problem mostly in forest soils. In this research the effect of land use and depth of the groundwater on Al, pH and DOC concentration in groundwater under Dutch sandy soils has been s

  17. UNESCO-L'ORÉAL-legat til argentinsk DMU-gæsteforsker

    DEFF Research Database (Denmark)

    Voigt, Steen

    2008-01-01

    Carolina Trochine, biolog, ph.d. og i fjor gæsteforsker ved Danmarks Miljøundersøgelser (DMU) ved Aarhus Universitet har modtaget UNESCO-L'ORÉAL's to-årige naturvidenskabelige forskerlegat "Young Women in Life Sciences" for 2008. Udgivelsesdato: 6. marts...

  18. Al2O3/Silicon NanoISFET with Near Ideal Nernstian Response

    NARCIS (Netherlands)

    Chen, Songyue; Bomer, Johan G.; Carlen, Edwin T.; Berg, van den Albert

    2011-01-01

    Nanoscale ISFET (ion sensitive field-effect transistor) pH sensors are presented that produce the well-known sub-Nernstian pH-response for silicon dioxide (SiO2) surfaces and near ideal Nernstian sensitivity for alumina (Al2O3) surfaces. Titration experiments of SiO2 surfaces resulted in a varying p

  19. Characterisation and deployment of an immobilised pH sensor spot towards surface ocean pH measurements.

    Science.gov (United States)

    Clarke, Jennifer S; Achterberg, Eric P; Rérolle, Victoire M C; Abi Kaed Bey, Samer; Floquet, Cedric F A; Mowlem, Matthew C

    2015-10-15

    The oceans are a major sink for anthropogenic atmospheric carbon dioxide, and the uptake causes changes to the marine carbonate system and has wide ranging effects on flora and fauna. It is crucial to develop analytical systems that allow us to follow the increase in oceanic pCO2 and corresponding reduction in pH. Miniaturised sensor systems using immobilised fluorescence indicator spots are attractive for this purpose because of their simple design and low power requirements. The technology is increasingly used for oceanic dissolved oxygen measurements. We present a detailed method on the use of immobilised fluorescence indicator spots to determine pH in ocean waters across the pH range 7.6-8.2. We characterised temperature (-0.046 pH/°C from 5 to 25 °C) and salinity dependences (-0.01 pH/psu over 5-35), and performed a preliminary investigation into the influence of chlorophyll on the pH measurement. The apparent pKa of the sensor spots was 6.93 at 20 °C. A drift of 0.00014 R (ca. 0.0004 pH, at 25 °C, salinity 35) was observed over a 3 day period in a laboratory based drift experiment. We achieved a precision of 0.0074 pH units, and observed a drift of 0.06 pH units during a test deployment of 5 week duration in the Southern Ocean as an underway surface ocean sensor, which was corrected for using certified reference materials. The temperature and salinity dependences were accounted for with the algorithm, R=0.00034-0.17·pH+0.15·S(2)+0.0067·T-0.0084·S·1.075. This study provides a first step towards a pH optode system suitable for autonomous deployment. The use of a short duration low power illumination (LED current 0.2 mA, 5 μs illumination time) improved the lifetime and precision of the spot. Further improvements to the pH indicator spot operations include regular application of certified reference materials for drift correction and cross-calibration against a spectrophotometric pH system. Desirable future developments should involve novel

  20. Arbejdsmiljø og karriere - to ph.d.-udfordringer

    Directory of Open Access Journals (Sweden)

    Trine Bovbjerg

    2013-09-01

    Full Text Available Artiklen afrapporterer de erkendelser omkring ph.d.-studerendes arbejdsmiljø og karriereudvikling, som vi har opnået i gennemførelsen af et udviklingsforløb for ph.d.-studerende på fire af landets universiteter i 2012-2013. De ph.d.-studerendes arbejdsmiljø er ikke særligt velbelyst, og igennem en analyse af deltagernes udviklingsplaner og evalueringer af forløbet vil vi pege på 4 karakteristikker ved arbejdsmiljøet: Work-life-balance, dobbelt identiet som både studerende og medarbejder, forventninger og krydspres samt usikre karriereveje. De ph.d.-studerende trives pga. engagementet i deres faglige forskningsprojekt, mens deres udfordringer med arbejds­miljøet primært bunder i kollegiale, ledelsesmæssige og organisatoriske forhold. For at få inspiration til forbedringer af de ph.d.-studerendes arbejdsmiljø foreslås det at anlægge et situeret læringsperspektiv på ph.d.-uddannelsen. Et situeret perspektiv inddrager dele af arbejdsmiljøet som væsentlig faktor for faglig udvikling.    Findings are reported for a development program for PhD students that took place in 2012/2013 at four Danish universities. The focus of the program was doctoral students’ work and career development. To date PhD students’ work environments have not been documented in detail, however, analysis of data collected during the program revealed four areas of concern to doctoral students: Challenges relating to work-life balance, uncertainty over identity relating to status as student and employee, risks associated with the work and uncertainty over career paths. The problems are primarily rooted in collegiate, managerial and organizational issues. In order to identify areas for improvement in the PhD students’ learning process, it is proposed that a situated learning perspective on the PhD programme be adopted.

  1. Local pH tracking in living cells

    Science.gov (United States)

    Tsou, Chieh-Jui; Hsia, Chih-Hao; Chu, Jia-Yin; Hung, Yann; Chen, Yi-Ping; Chien, Fan-Ching; Chou, Keng C.; Chen, Peilin; Mou, Chung-Yuan

    2015-02-01

    Continuous and simultaneous 3D single-particle movement and local pH detection in HeLa cells were demonstrated for the first time by combining fluorescent mesoporous silica nanoparticles (FMSNs) and a single-particle tracking (SPT) technique with a precision of ~10 nm. FMSNs, synthesized by the co-condensation of both pH-sensitive and reference dyes with a silica/surfactant source, allow long-term reliable ratiometric pH measurements with a precision better than 0.3 pH unit because of their excellent brightness and stability. pH variation in the surrounding area of FMSNs during endocytosis was monitored in real-time. Acidification and low mobility of FMSNs were observed at the early endocytic stage, whereas basification and high mobility of FMSNs were observed at the late stage. Our results indicate that it is possible to monitor local pH changes in the environments surrounding nanoparticles during the cellular uptake process of FMSNs, which provides much needed information for designing an efficient drug delivery nanosystem.Continuous and simultaneous 3D single-particle movement and local pH detection in HeLa cells were demonstrated for the first time by combining fluorescent mesoporous silica nanoparticles (FMSNs) and a single-particle tracking (SPT) technique with a precision of ~10 nm. FMSNs, synthesized by the co-condensation of both pH-sensitive and reference dyes with a silica/surfactant source, allow long-term reliable ratiometric pH measurements with a precision better than 0.3 pH unit because of their excellent brightness and stability. pH variation in the surrounding area of FMSNs during endocytosis was monitored in real-time. Acidification and low mobility of FMSNs were observed at the early endocytic stage, whereas basification and high mobility of FMSNs were observed at the late stage. Our results indicate that it is possible to monitor local pH changes in the environments surrounding nanoparticles during the cellular uptake process of FMSNs, which

  2. Thermal Modeling of Al-Al and Al-Steel Friction Stir Spot Welding

    Science.gov (United States)

    Jedrasiak, P.; Shercliff, H. R.; Reilly, A.; McShane, G. J.; Chen, Y. C.; Wang, L.; Robson, J.; Prangnell, P.

    2016-09-01

    This paper presents a finite element thermal model for similar and dissimilar alloy friction stir spot welding (FSSW). The model is calibrated and validated using instrumented lap joints in Al-Al and Al-Fe automotive sheet alloys. The model successfully predicts the thermal histories for a range of process conditions. The resulting temperature histories are used to predict the growth of intermetallic phases at the interface in Al-Fe welds. Temperature predictions were used to study the evolution of hardness of a precipitation-hardened aluminum alloy during post-weld aging after FSSW.

  3. Effect of systemic pH on pH sub i and lactic acid generation in exhaustive forearm exercise

    Energy Technology Data Exchange (ETDEWEB)

    Hood, V.L.; Schubert, C.; Keller, U.; Mueller, S. (Univ. of Basel (Switzerland) Univ. of Vermont College of Medicine, Burlington (USA))

    1988-09-01

    To investigate whether changes in systemic pH affect intracellular pH (pH{sub i}), energy-rich phosphates, and lactic acid generation in muscle, eight normal volunteers performed exhaustive forearm exercise with arterial blood flow occluded for 2 min on three occasions. Subjects ingested 4 mmol/kg NH{sub 4}Cl (acidosis; A) or NaHCO{sub 3} (alkalosis; B) or nothing (control; C) 3 h before the exercise. Muscle pH{sub i} and phosphocreatine (PCr) content were measured with {sup 31}P-nuclear magnetic resonance ({sup 31}P-NMR) spectroscopy during exercise and recovery. Lactate output during 0.5-7 min of recovery was calculated as deep venous-arterial concentration differences times forearm blood flow. Before exercise, blood pH and bicarbonate were lower in acidosis than alkalosis and intermediate in control. Lactic acid output during recovery was less with A than B and intermediate in C. PCr utilization and resynthesis were not affected by extracellular pH changes. pH{sub i} did not differ before exercise or at its end. Hence systemic acidosis inhibited and alkalosis stimulated lactic acid output. These findings suggest that systemic pH regulates cellular acid production, protecting muscle pH, at the expense of energy availability.

  4. PH2O-dependent structural phase transitions in the zeolite mesolite: Real- and reciprocal-space crystal structure refinements

    International Nuclear Information System (INIS)

    The response of the mesolite crystal structure (Na16Ca16Al48Si72O240·64H2O) to dehydration was evaluated as a function of temperature and partial pressure of water (i.e., PH2O or relative humidity, RH) using laboratory X-ray powder diffraction (XRD; CuKα radiation) and synchrotron X-ray pair distribution function (PDF) methods. At 425 C under low-PH2O conditions (PH2O (le) ∼1.3 mbar), dehydrated mesolite preserved the long-range ordered aluminosilicate framework structure, which has not been previously observed. This new dehydrated phase, x-metamesolite, has unit-cell parameters (a = 16.731(3) (angstrom), b = 17.822(2) (angstrom), c = 6.312(1) (angstrom), V = 1882.5(5) (angstrom)3, and possible space group Fdd2) similar to those of other dehydrated natrolite phases (either 1- or 2-metanatrolite). Conversely, under high-PH2O conditions (PH2O > ∼1.3 mbar), dehydrated mesolite became amorphous (amorphous T5O10) at 425 C. The local structure of amorphous T5O10 was characterized by PDF analyses, which showed the formation of twisted T5O10 nano-fibers (with dimensions (LWH) of ∼6.9 x 6.9 x 6.3 (angstrom)) resulting from breakage of the mesolite aluminosilicate framework. The two distinct high-temperature PH2O-dependent phase transition paths illustrate the importance of considering the combined effects of temperature and PH2O in mesolite. In addition, the low-temperature phase transition in mesolite, involving order-disorder of the extraframework cations, also showed a PH2O-dependent transition temperature. Although, there is no path dependence on PH2O for this transition, the local arrangement of Na, Ca, and vacancies in disordered metamesolite (formed through the extraframework cation order-disorder phase transition) likely influences the thermal stability of the aluminosilicate framework during further heating.

  5. KWIN nu ook als app

    NARCIS (Netherlands)

    Rotgers, G.; Vermeij, I.

    2014-01-01

    KWIN, Kwantitatieve Informatie Veehouderij, verscheen de afgelopen 25 jaar als lijvig handboek, zowel op papier als digitaal. Dit najaar is daar een serie apps bij gekomen, waarmee adviseurs en veehouders zelf saldo- en kostprijsberekeningen kunnen maken. De apps zijn beschikbaar voor de pluimvee-,

  6. Philosophieren als Unterrichtsprinzip im Mathematikunterricht

    Science.gov (United States)

    Meerwaldt, Diana

    Philosophieren und Mathematik scheinen zunächst gegensätzliche Bereiche zu sein, die sich kaum vereinbaren lassen. Dies trifft für eine Auffassung zu, die Philosophieren als "Gerede" disqualifiziert und Mathematik als eine reine "Formelwissenschaft" begreift. Beide Auffassungen werden den Gegenständen nicht gerecht.

  7. Sugar-based gemini surfactant with a vesicle-to-micelle transition at acidic pH and a reversible vesicle flocculation near neutral pH

    NARCIS (Netherlands)

    Johnsson, M; Wagenaar, A; Engberts, JBFN

    2003-01-01

    A sugar-based (reduced glucose) gemini surfactant forms vesicles in dilute aqueous solution near neutral pH. At lower pH, there is a vesicle-to-micelle transition within a narrow pH region (pH 6.0-5.6). The vesicles are transformed into large cylindrical micelles that in turn are transformed into sm

  8. pH Sensing and Regulation in Cancer

    Directory of Open Access Journals (Sweden)

    Mehdi eDamaghi

    2013-12-01

    Full Text Available Cells maintain intracellular pH (pHi within a narrow range (7.1-7.2 by controlling membrane proton pumps and transporters whose activity is set by intra-cytoplasmic pH sensors. These sensors have the ability to recognize and induce cellular responses to maintain the intracellular pH, often at the expense of acidifying the extracellular pH. In turn, extracellular acidification impacts cells via specific acid-sensing ion channels (ASICs and proton-sensing G-protein coupled receptors (GPCRs. In this review, we will discuss some of the major players in proton sensing at the plasma membrane and their downstream consequences in cancer cells and how these pH-mediated changes affect processes such as migration and metastasis. The complex mechanisms by which they transduce acid pH signals to the cytoplasm and nucleus are not well understood. However, there is evidence that expression of proton-sensing GPCRs such as GPR4, TDAG8, and OGR1 can regulate aspects of tumorigenesis and invasion, including colfilin and talin regulated actin (de-polymerization. Major mechanisms for maintenance of pHi homeostasis include monocarboxylate, bicarbonate and proton transporters. Notably, there is little evidence suggesting a link between their activities and those of the extracellular H+-sensors, suggesting a mechanistic disconnect between intra- and extra-cellular pH. Understanding the mechanisms of pH sensing and regulation may lead to novel and informed therapeutic strategies that can target acidosis, a common physical hallmark of solid tumors.

  9. A survey of beef muscle color and pH.

    Science.gov (United States)

    Page, J K; Wulf, D M; Schwotzer, T R

    2001-03-01

    The objectives of this study were to define a beef carcass population in terms of muscle color, ultimate pH, and electrical impedance; to determine the relationships among color, pH, and impedance and with other carcasses characteristics; and to determine the effect of packing plant, breed type, and sex class on these variables. One thousand beef carcasses were selected at three packing plants to match the breed type, sex class, marbling score, dark-cutting discount, overall maturity, carcass weight, and yield grade distributions reported for the U.S. beef carcass population by the 1995 National Beef Quality Audit. Data collected on these carcasses included USDA quality and yield grade data and measurements of muscle color (L*, a*, b*), muscle pH, and electrical impedance of the longissimus muscle. About one-half (53.1%) of the carcasses fell within a muscle pH range of 5.40 to 5.49, and 81.3% of the carcasses fell within a longissimus muscle pH range of 5.40 to 5.59. A longissimus muscle pH of 5.87 was the approximate cut-off between normal and dark-cutting carcasses. Frequency distributions indicated that L* values were normally distributed, whereas a* and b* values were abnormally distributed (skewed because of a longer tail for lower values, a tail corresponding with dark-cutting carcasses). Electrical impedance was highly variable among carcasses but was not highly related to any other variable measured. Color measurements (L*, a*, b*) were correlated (P Brahman-type (pH = 5.46, L* = 39.75, a* = 25.17, and b* = 11.05) carcasses (P < 0.05).

  10. Traceability of pH to the Mole

    Directory of Open Access Journals (Sweden)

    Maria Filomena Camões

    2015-08-01

    Full Text Available Free acidity of aqueous solutions was initially defined in 1909 by Søren Peter Lauritz Sørensen as pH = −lgcH+ (c/mol·dm−3 or m/mol·kg−1 of the free hydrogen ions in solution, H+ soon (1910 was changed to pH = paH+ = −lgaH+, integrating the new concepts of activity, ai and activity coefficient γi, for the ionic species i under concern, H+ in this case; it is ai = −lg(miγi. Since individual ions do not exist alone in solution, primary pH values cannot be assigned solely by experimental measurements, requiring extra thermodynamic model assumptions for the activity coefficient, γH+, which has put pH in a unique situation of not being fully traceable to the International System of Units (SI. Also the concept of activity is often not felt to be as perceptible as that of concentration which may present difficulties, namely with the interpretation of data. pH measurements on unknown samples rely on calibration of the measuring setup with adequate reference pH buffers. In this work, the assignment of pH values to buffers closely matching the samples, e.g., seawater, is revisited. An approach is presented to assess the quantity pmH+ = −lgmH+ profiting from the fact that, contrary to single ion activity coefficients, mean activity coefficients,   can be assessed based on experimentally assessed quantities alone, γExp ±, thus ensuring traceability to the mole, the SI base unit for amount of substance. Compatibility between γExp ± and mean activity coefficient calculated by means of Pitzer model equations, γPtz ±, validates the model for its intended use.

  11. Effects of pH values on the properties of buffalo and cow butter-based low-fat spreads

    Directory of Open Access Journals (Sweden)

    Abdeldaiem, A. M.

    2014-09-01

    períodos de almacenamiento fueron no significativas. La disminución en la dureza y la viscosidad de las muestras fueron proporcionales al incremento del pH, y los tratamientos aumentan los efectos durante los períodos de almacenamiento. En general, un aumento de los valores de pH no afectó a los perfiles de fusión de los untables. Además, se observaron cambios entre los perfiles de fusión de los untables bajos en grasa a base de mantequilla búfalos y vacas.

  12. Effect of Chlorhexidine with Fluoride Mouthrinse on Plaque Accumulation, Plaque pH - A Double Blind Parallel Randomized Clinical Trial

    Science.gov (United States)

    Saha, Sabyasachi; Singh, Sanjay

    2016-01-01

    Introduction Mouthwashes are important means used in chemical control of dental plaque. There is strong evidence suggestive of better effectiveness, when fluoride is added to chlorhexidine mouthwash. Aim To assess the anti-plaque efficacy of Chlorhexidine combined with Fluoride mouthwash and to measure its impact on plaque accumulation and on plaque pH. Materials and Methods Initially 100 subjects were screened. A double blind, parallel randomized clinical trial was conducted on 30 subjects after applying inclusion and exclusion criteria. Other independent variables were matched before randomly allocating them in three groups: Group A-Chlorhexidine as positive control, Group B-Chlorhexidine + Fluoride as test group and Group C- Distilled water as negative control. Oral prophylaxis of participants was done before onset of the study. Plaque pH was assessed before and immediately after rinsing at 0, 5 and 10 minutes interval and after 7 days with digital pH electrode (pHepR pH meter, Hanna Instruments R10285) and accumulation of plaque was recorded by Turesky et al., modification of Quigley Hein Plaque Index (1970). ANOVA test was used for statistical analysis. Results Although there was a statistically significant reduction in mean plaque scores from baseline to seven days in both Groups A and B, Group B showed better anti-plaque efficacy . Almost equal drop in plaque pH was seen for both the groups at 5 and 10 minutes. Conclusion Better anti-plaque efficacy was observed in Group B (Chlorhexidine and Fluoride combination) with minimum variation of plaque pH.

  13. Synthesis, structure and gas-phase reactivity of the mixed silver hydride borohydride nanocluster [Ag3(μ3-H)(μ3-BH4)L(Ph)3]BF4 (L(Ph) = bis(diphenylphosphino)methane).

    Science.gov (United States)

    Zavras, Athanasios; Ariafard, Alireza; Khairallah, George N; White, Jonathan M; Mulder, Roger J; Canty, Allan J; O'Hair, Richard A J

    2015-11-21

    Borohydrides react with silver salts to give products that span multiple scales ranging from discrete mononuclear compounds through to silver nanoparticles and colloids. The cluster cations [Ag3(H)(BH4)L3](+) are observed upon electrospray ionization mass spectrometry of solutions containing sodium borohydride, silver(I) tetrafluoroborate and bis(dimethylphosphino)methane (L(Me)) or bis(diphenylphosphino)methane (L(Ph)). By adding NaBH4 to an acetonitrile solution of AgBF4 and L(Ph), cooled to ca. -10 °C, we have been able to isolate the first mixed silver hydride borohydride nanocluster, [Ag3(μ3-H)(μ3-BH4)L(Ph)3]BF4, and structurally characterise it via X-ray crystallography. Combined gas-phase experiments (L(Me) and L(Ph)) and DFT calculations (L(Me)) reveal how loss of a ligand from the cationic complexes [Ag3(H)(BH4)L3](+) provides a change in geometry that facilitates subsequent loss of BH3 to produce the dihydride clusters, [Ag3(H)2Ln](+) (n = 1 and 2). Together with the results of previous studies (Girod et al., Chem. - Eur. J., 2014, 20, 16626), this provides a direct link between mixed silver hydride/borohydride nanoclusters, silver hydride nanoclusters, and silver nanoclusters.

  14. Variation in Biofilm Stability with Decreasing pH Affects Porous Medium Hydraulic Properties

    Science.gov (United States)

    Kirk, M. F.; Santillan, E. F.; McGrath, L. K.; Altman, S. J.

    2010-12-01

    Changes to microbial communities caused by subsurface CO2 injection may have many consequences, including possible impacts to CO2 transport. We used column experiments to examine how decreasing pH, a geochemical change associated with CO2 injection, will affect biofilm stability and ultimately the hydraulic properties of porous media. Columns consisted of 1 mm2 square capillary tubes filled with 105-150 µm diameter glass beads. Artificial groundwater medium containing 1 mM glucose was pumped through the columns at a rate of 0.01 mL/min (q = 14.4 m/day; Re = 0.03). Columns were inoculated with 3 × 10^8 CFU (avg.) of Pseudomonas fluorescens, a model biofilm former, transformed with a green fluorescent protein. Biomass distribution and transport was examined using scanning laser confocal microscopy and effluent plating. Variation in the bulk hydraulic properties of the columns was measured using manometers. In an initial experiment, biofilm growth was allowed to occur for seven days in medium with pH 7.3. Within this period, cells uniformly coated bead surfaces, effluent cell numbers stabilized at 1 × 10^9 CFU/mL, and hydraulic conductivity (K) decreased 77%. Next, medium with pH 4 was introduced. As a result, biomass within the reactor redistributed from bead surfaces to pores, effluent cell numbers decreased to 3 × 10^5 CFU/mL, and K decreased even further (>94% reduction). This decreased K was maintained until the experiment was terminated, seven days after introducing low pH medium. These results suggest that changes in biomass distribution as a result of decreased pH may initially limit transport of solubility-trapped CO2 following CO2 injection. Experiments in progress and planned will test this result in more detail and over longer periods of time. This material is based upon work supported as part of the Center for Frontiers of Subsurface Energy Security, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office

  15. Effect of pH on boron adsorption in some soils of Paraná, Brazil

    Directory of Open Access Journals (Sweden)

    Fábio Steiner

    2013-06-01

    Full Text Available Temporary B deficiency can be triggered by liming of acid soils because of increased B adsorption at higher soil pH. Plants respond directly to the activity of B in soil solution and only indirectly to B adsorbed on soil constituents. Because the range between deficient and toxic B concentration is relatively narrow, this poses difficulty in maintaining appropriate B levels in soil solution. Thus, knowledge of the chemical behavior of B in the soil is particularly important. The present study investigated the effect of soil pH on B adsorption in four soils of Paraná State, and to correlate these values with the physical and chemical properties of the soils. Surface samples were taken from a Rhodic Hapludox, Arenic Hapludalf, Arenic Hapludult, and one Typic Usthorthent. To evaluate the effect of pH on B adsorption, subsamples soil received the application of increasing rates of calcium carbonate. Boron adsorption was accomplished by shaking 2.0 g soil, for 24 h, with 20 mL of 0.01 mol L¹ NaCl solution containing different concentrations (0.0, 0.1, 0.2, 0.4, 0.8, 1.2, 1.6, 2.0, and 4.0 mg B L-1. Sorption was fitted to non-linear form of the Langmuir adsorption isotherm. Boron adsorption increased as concentration increased. Boron adsorption was dependent on soil pH, increasing as a function of pH in the range between 4.6 and 7.4, although the bonding energy has decreased. Maximum adsorption capacity (MAC of B was observed in the Arenic Hapludalf (49.8 mg B kg-1 soil followed by Arenic Hapludult (22.5 mg kg-1, Rhodic Hapludox (17.4 mg kg-1, and Typic Usthorthent (7.0 mg kg-1. The organic matter content, clay content, and aluminum oxide content (Al2O3 were the soils properties that affecting the B adsorption on Paraná soils.

  16. An updated pH calculation tool for new challenges

    Energy Technology Data Exchange (ETDEWEB)

    Crolet, J.L. [Consultant, 36 Chemin Mirassou, 64140 Lons (France)

    2004-07-01

    The time evolution of the in-situ pH concept is summarised, as well as the past and present challenges of pH calculations. Since the beginning of such calculations on spread sheets, the tremendous progress in the computer technology has progressively removed all its past limitations. On the other hand, the development of artificial acetate buffering in standardized and non-standardized corrosion testing has raised quite a few new questions. Especially, a straightforward precautionary principle now requires to limit all what is artificial to situations where this is really necessary and, consequently, seriously consider the possibility of periodic pH readjustment as an alternative to useless or excessive artificial buffering, including in the case of an over-acidification at ambient pressure through HCl addition only (e.g. SSC testing of martensitic stainless steels). These new challenges require a genuine 'pH engineering' for the design of corrosion testing protocols under CO{sub 2} and H{sub 2}S partial pressures, at ambient pressure or in autoclave. In this aim, not only a great many detailed pH data shall be automatically delivered to unskilled users, but this shall be done in an experimental context which is most often new and much more complicated than before: e.g. pH adjustment of artificial buffers before saturation in the test gas and further pH evolution under acid gas pressure (pH shift before test beginning), anticipation of the pH readjustment frequency from just a volume / surface ratio and an expected corrosion rate (pH drift during the test). Furthermore, in order to be really useful and reliable, such numerous pH data have also to be well understood. Therefore, their origin, significance and parametric sensitivity are backed up and explained through three self-understanding graphical illustrations: 1. an 'anion - pH' nomogram shows the pH dependence of all the variable ions, H{sup +}, HCO{sub 3}{sup -}, HS{sup -}, Ac{sup -} (and

  17. PH5 for integrating and archiving different data types

    Science.gov (United States)

    Azevedo, Steve; Hess, Derick; Beaudoin, Bruce

    2016-04-01

    PH5 is IRIS PASSCAL's file organization of HDF5 used for seismic data. The extensibility and portability of HDF5 allows the PH5 format to evolve and operate on a variety of platforms and interfaces. To make PH5 even more flexible, the seismic metadata is separated from the time series data in order to achieve gains in performance as well as ease of use and to simplify user interaction. This separation affords easy updates to metadata after the data are archived without having to access waveform data. To date, PH5 is currently used for integrating and archiving active source, passive source, and onshore-offshore seismic data sets with the IRIS Data Management Center (DMC). Active development to make PH5 fully compatible with FDSN web services and deliver StationXML is near completion. We are also exploring the feasibility of utilizing QuakeML for active seismic source representation. The PH5 software suite, PIC KITCHEN, comprises in-field tools that include data ingestion (e.g. RefTek format, SEG-Y, and SEG-D), meta-data management tools including QC, and a waveform review tool. These tools enable building archive ready data in-field during active source experiments greatly decreasing the time to produce research ready data sets. Once archived, our online request page generates a unique web form and pre-populates much of it based on the metadata provided to it from the PH5 file. The data requester then can intuitively select the extraction parameters as well as data subsets they wish to receive (current output formats include SEG-Y, SAC, mseed). The web interface then passes this on to the PH5 processing tools to generate the requested seismic data, and e-mail the requester a link to the data set automatically as soon as the data are ready. PH5 file organization was originally designed to hold seismic time series data and meta-data from controlled source experiments using RefTek data loggers. The flexibility of HDF5 has enabled us to extend the use of PH5 in several

  18. Macroscopic and spectroscopic characterization of selenate, selenite, and chromate adsorption at the solid-water interface of gamma-Al(2)O(3).

    Science.gov (United States)

    Elzinga, Evert J; Tang, Yuanzhi; McDonald, Jason; DeSisto, Stephanie; Reeder, Richard J

    2009-12-15

    The interaction of selenate, selenite, and chromate with the hydrated surface of gamma-Al(2)O(3) was studied using a combination of macroscopic pH edge data, electrophoretic mobility measurements, and X-ray absorption spectroscopic analyses. The pH edge data show generally increased oxyanion adsorption with decreasing pH, and indicate ionic strength-(in)dependent adsorption of chromate and selenate across the pH range 4-9, and ionic strength-(in)dependent adsorption of selenite in this pH range. The adsorption of chromate peaks at pH 5.0, whereas for selenate and selenite no pH adsorption maxima are observed. Electrophoretic mobility measurements show that all three oxyanions decrease the zeta potential of gamma-Al(2)O(3) upon adsorption; however, only selenite decreased the pH(PZC) of the gamma-Al(2)O(3) sorbent. EXAFS data indicate that selenite ions are coordinated in a bridging bidentate fashion to surface AlO(6) octahedra, whereas no second-neighbor Al scattering was observed for adsorbed selenate ions. Combined, the results presented here show that pH is a major factor in determining the extent of adsorption of selenate, selenite, and chromate on hydrated gamma-Al(2)O(3). The results point to substantial differences between these anions as to the mode of adsorption at the hydrated gamma-Al(2)O(3) surface, with selenate adsorbing as nonprotonated outer-sphere complexes, chromate forming a mixture of monoprotonated and nonprotonated outer-sphere adsorption complexes, and selenite coordinating as inner-sphere surface complexes in bridging configuration.

  19. A Self-Powered Triboelectric Nanosensor for PH Detection

    Directory of Open Access Journals (Sweden)

    Ying Wu

    2016-01-01

    Full Text Available A self-powered, sliding electrification based triboelectric sensor was developed for detecting PH value from a periodic contact/separation motion. This innovative, cost-effective, simply designed sensor is composed of a fluorinated ethylene propylene thin film and an array of electrodes underneath. The operation of the TENG (triboelectric nanogenerator sensor relies on a repetitive emerging-submerging process with traveling solution waves, in which the coupling between triboelectrification and electrostatic induction gives rise to alternating flows of electrons between electrodes. On the basis of coupling effect between triboelectrification and electrostatic induction, the sensor generates electric output signals which are associated with PH value. Experimental results show that the output voltage of the TENG sensor increases with the increasing PH value, which indicate that the PH value of different solution can be real-time monitored. This work not only demonstrates a new principle in the field of PH value measurement but also greatly expands the applicability of triboelectric nanogenerator (TENG as self-powered sensors.

  20. The Production Rate and Employment of Ph.D. Astronomers

    CERN Document Server

    Metcalfe, Travis S

    2007-01-01

    In an effort to promote self-regulation of the astronomy job market, I examine the supply of, and demand for, astronomers over time. On the supply side, I document the production rate of Ph.D. astronomers from 1970 to 2006 using the UMI Dissertation Abstracts database, along with data from other independent sources. I compare the long-term trends in Ph.D. production with federal astronomy research funding over the same time period, and I demonstrate that additional funding is correlated with higher subsequent Ph.D. production. On the demand side, I monitor the changing patterns of employment using statistics about the number and types of jobs advertised in the AAS Job Register from 1984 to 2006. Finally, I assess the sustainability of the job market by normalizing this demand by the annual Ph.D. production. The most recent data suggest that there are now annual advertisements for about one postdoctoral job, half a faculty job, and half a research/support position for every new domestic Ph.D. recipient in astr...

  1. Intracellular pH and the Control of Multidrug Resistance

    Science.gov (United States)

    Simon, Sanford; Roy, Deborshi; Schindler, Melvin

    1994-02-01

    Many anticancer drugs are classified as either weak bases or molecules whose binding to cellular structures is pH dependent. Accumulation of these drugs within tumor cells should be affected by transmembrane pH gradients. Indeed, development of multidrug resistance (MDR) in tumor cells has been correlated with an alkaline shift of cytosolic pH. To examine the role of pH in drug partitioning, the distribution of two drugs, doxorubicin and daunomycin, was monitored in fibroblasts and myeloma cells. In both cell types the drugs rapidly accumulated within the cells. The highest concentrations were measured in the most acidic compartments-e.g., lysosomes. Modifying the cellular pH in drug-sensitive cells to mimic reported shifts in MDR caused an immediate change in the cellular drug concentration. Drug accumulation was enhanced by acidic shifts and reversed by alkaline shifts. All of these effects were rapid and reversible. These results demonstrate that the alkaline shift observed in MDR is sufficient to prevent the accumulation of chemotherapeutic drugs independent of active drug efflux.

  2. Polymeric gel nanoparticle pH sensors for intracellular measurements

    DEFF Research Database (Denmark)

    Almdal, Kristoffer; Andresen, Thomas Lars; Benjaminsen, Rikke Vicki;

    pH range is approximately 4 pH units and thus a nanoparticle sensor with two pH sensitive fluorophores is appropriate. With one pH sensitive fluorophore the output from the sensor follows R=R0+R1/10(pKa-pH), where R is the ratio of fluorescence for the two fluorophores, R0 is the minimum value of R......, and R0+R1 is the maximum value of R. Suteable choice of fluorophores, here Rhodamin B as reference and Oregon green (OG) and Flurescin (FA) as pH sensitive fluorophores gives a nanoparticle sensor with the calibration curve shown in the Figure. The fluorophores are derivatized to allow for covalent...... bonding to the gel nanoparticle. The synthesis also allows for introduction of charged groups. Particle charge influence the cell uptake heavily. The synthesis scheme is outlined below. The sensors are internalized in cells through endocytosis and the sensor allows for the accurate measurement of p...

  3. pH responsive graft copolymers of chitosan.

    Science.gov (United States)

    Yilmaz, Elvan; Yalinca, Zulal; Yahya, Kovan; Sirotina, Uliana

    2016-09-01

    Grafting suitable polymers onto chitosan can produce cationic or polyampholyte polymers or hydrogels that are potential smart biomedical materials. Chitosan-graft-[poly(diethylamino)ethyl methacrylate] has been prepared in three different physical forms as linear free chains in solution, chemical gels crosslinked with glutaraldehyde, and poly(diethylamino)ethyl methacrylate] grafted onto chitosan tripolyphosphate gel beads. In addition to chemical structure, the graft copolymers were characterized with respect to their dissolution and swelling behavior in aqueous solution. It has been established that solubility of the products is controlled by the grafting yield. While pH sensitive polymers, which collapse at a given pH value are obtained at lower grafting yields, hydrogels form at higher grafting yields with pH responsive swelling behavior. Glutaraldehyde crosslinked chitosan-graft-[poly(diethylamino)ethyl methacrylate] gels and chitosan tripolyphosphate gel beads grafted with poly[(diethylamino)ethyl methacrylate] exhibit pH sensitive swelling with highest equilibrium swelling capacity at pH=1.2. PMID:26500176

  4. Solid phase synthesis and biological evaluation of enantiomerically pure wasp toxin analogues PhTX-343 and PhTX-12

    DEFF Research Database (Denmark)

    Strømgaard, K; Bjørnsdottir, I; Andersen, K;

    2000-01-01

    ) of the enantiomers of PhTX-343 and PhTX-12. The methods were optimised with respect to chiral selector, buffer pH, and temperature around the capillary. Thus, rac-PhTX-343 was resolved using a separation buffer containing 30 mM heptakis-(2, 6-di-O-methyl)-beta-cyclodextrin in 50 mM 6-aminocarproic acid (pH 4. 0...

  5. El miedo al rey

    Directory of Open Access Journals (Sweden)

    François FORONDA

    2007-01-01

    Full Text Available La peur du roi. Sources et premières réflexions à propos d’une émotion aristocratique dans la Castille du XIVe siècleFace à un roi qui à présent pousse les effets de son ire jusqu’au meurtre pour faire le vide autour de lui et imposer sa différence souveraine, ses parents et les riches hommes, soit les principaux visés par cette politique de l’arbitraire qui enfreint les règles du jeu autant qu’elle contribue à les redéfinir, disent la peur (metus qu’ils ressentent, qu’ils utilisent aussi afin de donner à leur stratégie de pouvoir un fondement légitime. Et l’expression de cette émotion politique, qui tend à se muer en un stéréotype d’un discours aristocratique d’opposition, surtout présente dans les chroniques, mises ici en relation ici avec d’autres sources, notamment des correspondances, marque profondément l’histoire des relations souvent conflictuelles au sein de cette compagnie en définitive très étroite pendant un siècle, de la fin du XIIIe siècle à la fin du XIVe siècle. Cet article se propose d’ébaucher une première réflexion sur le sujet et d’en présenter les principales sources.El miedo al rey. Fuentes y primeras reflexiones acerca de una emoción aristocrática en la Castilla del siglo XIVFrente a un rey que ahora lleva hasta la muerte los efectos de su ira para hacer el vacío entorno a su persona e imponer su soberana, sus parientes y ricos hombres, o sea los principales afectados por esta política de la arbitrariedad que rompe las reglas del juego a la vez que contribuye a redefinirlas, dicen el miedo (metus que sienten, que utilizan también para darle a su estrategia de poder un fundamento legítimo. Y la expresión de esta emoción política, que tiende a convertirse en un estereotipo de un discurso aristocrático de oposición, sobre todo presente en la crónicas, aquí puestas en relación con otras fuentes, en particular cartas, marca profundamente la historia de

  6. Chemical modification and pH dependence of kinetic parameters to identify functional groups in a glucosyltransferase from Strep. Mutans

    Energy Technology Data Exchange (ETDEWEB)

    Bell, J.E.; Leone, A.; Bell, E.T.

    1986-05-01

    A glucosyltransferase, forming a predominantly al-6 linked glucan, was partially purified from the culture filtrate of S. mutans GS-5. The kinetic properties of the enzyme, assessed using the transfer of /sup 14/C glucose from sucrose into total glucan, were studied at pH values from pH 3.5 to 6.5. From the dependence of km on pH, a group with pKa = 5.5 must be protonated to maximize substrate binding. From plots of V/sub max/ vs pH two groups, with pKa's of 4.5 and 5.5 were indicated. The results suggest the involvement of either two carboxyl groups (one protonated, one unprotonated in the native enzyme) or a carboxyl group (unprotonated) and some other protonated group such as histidine, cysteine. Chemical modification studies showed that Diethylyrocarbonate (histidine specific) had no effect on enzyme activity while modification with p-phydroxy-mercuribenzoate or iodoacetic acid (sulfhydryl reactive) and carbodimide reagents (carboxyl specific) resulted in almost complete inactivation. Activity loss was dependent upon time of incubation and reagent concentration. The disaccharide lylose, (shown to be an inhibitor of the enzyme with similar affinity to sucrose) offers no protection against modification by the sulfhydryl reactive reagents.

  7. Hydrogen Desorption Properties of Bulk and Nanoconfined LiBH4-NaAlH4

    Directory of Open Access Journals (Sweden)

    Payam Javadian

    2016-06-01

    Full Text Available Nanoconfinement of 2LiBH4-NaAlH4 into a mesoporous carbon aerogel scaffold with a pore size, BET surface area and total pore volume of Dmax = 30 nm, SBET = 689 m2/g and Vtot = 1.21 mL/g, respectively is investigated. Nanoconfinement of 2LiBH4-NaAlH4 facilitates a reduction in the temperature of the hydrogen release by 132 °C, compared to that of bulk 2LiBH4-NaAlH4 and the onset of hydrogen release is below 100 °C. The reversible hydrogen storage capacity is also significantly improved for the nanoconfined sample, maintaining 83% of the initial hydrogen content after three cycles compared to 47% for that of the bulk sample. During nanoconfinement, LiBH4 and NaAlH4 reacts to form LiAlH4 and NaBH4 and the final dehydrogenation products, obtained at 481 °C are LiH, LiAl, AlB2 and Al. After rehydrogenation of the nanoconfined sample at T = 400 °C and p(H2 = 126 bar, amorphous NaBH4 is recovered along with unreacted LiH, AlB2 and Al and suggests that NaBH4 is the main compound that can reversibly release and uptake hydrogen.

  8. Quantum dots formed in InSb/AlAs and AlSb/AlAs heterostructures

    Science.gov (United States)

    Abramkin, D. S.; Rumynin, K. M.; Bakarov, A. K.; Kolotovkina, D. A.; Gutakovskii, A. K.; Shamirzaev, T. S.

    2016-06-01

    The crystal structure of new self-assembled InSb/AlAs and AlSb/AlAs quantum dots grown by molecularbeam epitaxy has been investigated by transmission electron microscopy. The theoretical calculations of the energy spectrum of the quantum dots have been supplemented by the experimental data on the steady-state and time-resolved photoluminescence spectroscopy. Deposition of 1.5 ML of InSb or AlSb on the AlAs surface carried out in the regime of atomic-layer epitaxy leads to the formation of pseudomorphically strained quantum dots composed of InAlSbAs and AlSbAs alloys, respectively. The quantum dots can have the type-I and type-II energy spectra depending on the composition of the alloy. The ground hole state in the quantum dot belongs to the heavy-hole band and the localization energy of holes is much higher than that of electrons. The ground electron state in the type-I quantum dots belongs to the indirect X XY valley of the conduction band of the alloy. The ground electron state in the type-II quantum dots belongs to the indirect X valley of the conduction band of the AlAs matrix.

  9. Correlation of transmissive fractures in holes OL-PH1, ONK-PH2 .. ONK-PH7 and ONKALO tunnel fractures

    International Nuclear Information System (INIS)

    In a preceding study Posiva flow logging (PFL) with a 0.5 m test interval and 10 cm steps has been used together with optical drillhole images and core logging fracture data for the exact determination of the depth of hydraulically conductive fractures in pilot holes. The fracture traces has been mapped from the ONKALO tunnel walls as a part of the systematic mapping. The mapping results has been digitized to a 3D tunnel layout in Surpac Vision programme. The data integrity and fracture trace uniqueness has been verified by Datactica Oy and further collected to a database (RakokantaDatacticaPosiva20091119.mdb). Water leakage of the mapped fractures exists as an attribute field for each fracture, but the value of the attribute has not been assessed conclusively. Those fractures mapped with leakage attribute have been defined as flowing, dripping, wet, or damp where the attribute is recorded. The fractures with no leakage attribute value appear to be dry (not leaking) or the information is not available (assessment was not performed). The water leaking surfaces on ONKALO tunnel wall have been mapped sequentially and conclusively (twice a year) as a part of the Olkiluoto monitoring program (OMO) using an equal five step measure as used with fracture traces in systematic mapping. The PFL results correlated with core logging fracture data from pilot holes OL-PH1 and ONK-PH2 .. ONK-PH7 were in this work further correlated with the fractures mapped from the ONKALO tunnel walls. Each hydraulically conductive fracture of OL-PH1 and ONK-PH2 - ONK-PH7 was investigated and linked to ONKALO fracture of a coherent orientation and matching location, where such fracture trace was available. The main objective of the work was to identify the ONKALO fractures which correspond to the flow from fracture(s) identified with the PFL method in pilot holes and to collect basic information about the occurrence, frequency and orientation of water bearing fractures along ONKALO tunnel. The

  10. The Renal Sodium Bicarbonate Cotransporter NBCe2: Is It a Major Contributor to Sodium and pH Homeostasis?

    Science.gov (United States)

    Felder, Robin A; Jose, Pedro A; Xu, Peng; Gildea, John J

    2016-09-01

    The sodium bicarbonate cotransporter (NBCe2, aka NBC4) was originally isolated from the human testis and heart (Pushkin et al. IUBMB Life 50:13-19, 2000). Subsequently, NBCe2 was found in diverse locations where it plays a role in regulating sodium and bicarbonate transport, influencing intracellular, extracellular, interstitial, and ultimately plasma pH (Boron et al. J Exp Biol. 212:1697-1706, 2009; Parker and Boron, Physiol Rev. 93:803-959, 2013; Romero et al. Mol Asp Med. 34:159-182, 2013). NBCe2 is located in human and rodent renal-collecting duct and proximal tubule. While much is known about the two electrogenic sodium bicarbonate cotransporters, NBCe1 and NBCe2, in the regulation of sodium homeostasis and pH balance in the rodent kidney, little is known about their roles in human renal physiology. NBCe2 is located in the proximal tubule Golgi apparatus under basal conditions and then disperses throughout the cell, but particularly into the apical membrane microvilli, during various maneuvers that increase intracellular sodium. This review will summarize our current understanding of the distribution and function of NBCe2 in the human kidney and how genetic variants of its gene, SLC4A5, contribute to salt sensitivity of blood pressure. PMID:27628629

  11. Adsorción de cadmio, cromo y mercurio en suelos del Valle del Cauca a varios valores de pH Cadmium, chromium and mercury adsorption on Cauca Valley soils as a function of pH

    Directory of Open Access Journals (Sweden)

    García O. Álvaro

    1991-12-01

    Full Text Available Con el fin de observar el proceso de adsorción de Cd, Cr y Hg y determinar el efecto del pH sobre la adsorción de los metales indicados, se seleccionaron tres suelos de los órdenes predominantes en el Valle del Cauca que, por su ubicación, están siendo regados con aguas contaminadas o pueden llegar a serlo en un futuro. El pH de los suelos se ajustó con ácido acético al 1, 4 y 12% o con NaOH 0.01 N para obtener valores lo más próximo posible a 5.7, 6.5 Y 7.8. Se prepararon soluciones de equilibrio con cada metal (0.0, 0.28, 0.56, 1.12 Y 2.25 mg/L y se adicionaron a 0.25 g de suelo seco al aire y tamizado para pasar una malla de 2 mm. La extracción de los metales se realizó con HCI 001 N y se determinaron por espectrofotometría de absorción atómica. La diferencia entre la concentración inicial y la final se consideró como la cantidad adsorbida por el suelo y la diferencia entre la cantidad adsorbida y la cantidad extraída con H Cl 0.01 N se consideró como la cantidad retenida por el suelo. En general el Cd se adsorbe más a valores de pH neutro o alcalino en todos los suelos, debido a que su forma predominante es la divalente y tiende más a formar complejos solubles e insolubles con los aniones encontrados en el suelo por encima de pH 7.0. La adsorción de Cr y Hg es mayor a valores de pH ácido debido a que forman complejos con la materia orgánica del suelo y/o los óxidos e hidróxidos de Fe, Al y Mn cuyas reacciones se ven favorecidas a estos valores de pH. La menor extracción (mayor retención en todos los suelos se dio a valores de pH entre 6.4 y 6.6, indicando que en este pH los metales quedan fuertemente retenidos por el complejo de cambio y su disponibilidad hacia las plantas es mínima.Soils irrigated with heavy metals contamined water are common in Cauca Valley and there is not available information about of soil behavior and soil processes affected by Cd, Cr and Hg. Three soils of the main orders of Cauca Valley

  12. Cowpea symbiotic efficiency, pH and aluminum tolerance in nitrogen-fixing bacteria

    Directory of Open Access Journals (Sweden)

    Bruno Lima Soares

    2014-06-01

    Full Text Available Cowpea (Vigna unguiculata cultivation in northern and northeastern Brazil provides an excellent source of nutrients and carbohydrates for the poor and underprivileged. Production surplus leads to its consumption in other regions of Brazil and also as an export commodity. Its capacity to establish relationships with atmospheric nitrogen-fixing bacteria is crucial to the reduction of production costs and the environmental impact of nitrogen fertilizers. This study assessed the symbiotic efficiency of new strains of symbiotic nitrogen-fixing bacteria with cowpea and their tolerance to pH and aluminum. Twenty-seven strains of bacteria from different soils were evaluated under axenic conditions. These strains were compared to the following inoculant strains: INPA03-11B, UFLA03-84 and BR3267 and two controls that were not inoculated (with and without mineral nitrogen. Six strains and the three strains approved as inoculants were selected to increase the dry weight production of the aerial part (DWAP and were tested in pots with soil that had a high-density of nitrogen-fixing native rhizobia. In this experiment, three strains (UFLA03-164, UFLA03-153, and UFLA03-154 yielded higher DWAP values. These strains grow at pH levels of 5.0, 6.0, 6.8 and at high aluminum concentration levels, reaching 10(9 CFU mL-1. In particular UFLA03-84, UFLA03-153, and UFLA03-164 tolerate up to 20 mmol c dm-3 of Al+3. Inoculation with rhizobial strains, that had been carefully selected according to their ability to nodulate and fix N2, combined with their ability to compete in soils that are acidic and contain high levels of Al, is a cheaper and more sustainable alternative that can be made available to farmers than mineral fertilizers.

  13. Intracellular pH Modulates Autophagy and Mitophagy.

    Science.gov (United States)

    Berezhnov, Alexey V; Soutar, Marc P M; Fedotova, Evgeniya I; Frolova, Maria S; Plun-Favreau, Helene; Zinchenko, Valery P; Abramov, Andrey Y

    2016-04-15

    The specific autophagic elimination of mitochondria (mitophagy) plays the role of quality control for this organelle. Deregulation of mitophagy leads to an increased number of damaged mitochondria and triggers cell death. The deterioration of mitophagy has been hypothesized to underlie the pathogenesis of several neurodegenerative diseases, most notably Parkinson disease. Although some of the biochemical and molecular mechanisms of mitochondrial quality control are described in detail, physiological or pathological triggers of mitophagy are still not fully characterized. Here we show that the induction of mitophagy by the mitochondrial uncoupler FCCP is independent of the effect of mitochondrial membrane potential but dependent on acidification of the cytosol by FCCP. The ionophore nigericin also reduces cytosolic pH and induces PINK1/PARKIN-dependent and -independent mitophagy. The increase of intracellular pH with monensin suppresses the effects of FCCP and nigericin on mitochondrial degradation. Thus, a change in intracellular pH is a regulator of mitochondrial quality control. PMID:26893374

  14. An analysis of Ph.D. examiners' reports in engineering

    Science.gov (United States)

    Prieto, Elena; Holbrook, Allyson; Bourke, Sid

    2016-03-01

    In recent years, there have been increasing calls for an overall transformation of the nature of engineering Ph.D. programs and the way theses are assessed. There exists a need to understand the examination process to ensure the best quality outcome for candidates in engineering. The work we present in this paper uses data collected between 2003 and 2010 for a total of 1220 Australian Ph.D. theses by analysing examiner reports. Our analysis indicates that Ph.D. theses in engineering, N = 106, differ considerably from those in other fields in areas such as gender of candidates and examiners and the examiners' geographical location. We also found that assessment areas such as significance and contribution of the thesis, publications arising from the thesis, breadth, depth and recency of the literature review and communication and editorial correctness are areas in which the proportion of text of engineering examiners' comments differs significantly from other fields.

  15. Controllable dissociations of PH3 molecules on Si(001)

    Science.gov (United States)

    Liu, Qin; Lei, Yanhua; Shao, Xiji; Ming, Fangfei; Xu, Hu; Wang, Kedong; Xiao, Xudong

    2016-04-01

    We demonstrate for the first time to our knowledge that controllable dissociation of PH3 adsorption products PH x (x = 2, 1) can be realized by STM (scanning tunneling microscope) manipulation techniques at room temperature. Five dissociative products and their geometric structures are identified via combining STM experiments and first-principle calculations and simulations. In total we realize nine kinds of controllable dissociations by applying a voltage pulse among the PH3-related structures on Si(001). The dissociation rates of the five most common reactions are measured by the I-t spectrum method as a function of voltage. The suddenly increased dissociation rate at 3.3 V indicates a transition from multivibrational excitation to single-step excitation induced by inelastic tunneling electrons. Our studies prove that selectively breaking the chemical bonds of a single molecule on semiconductor surface by STM manipulation technique is feasible.

  16. IMPACT OF WATER PH ON ZEBRA MUSSEL MORTALITY

    International Nuclear Information System (INIS)

    The experiments conducted this past quarter have suggested that the bacterium Pseudomonas fluorescens strain CL0145A is effective at killing zebra mussels throughout the entire range of pH values tested (7.2 to 8.6). Highest mortality was achieved at pH values characteristic of preferred zebra mussel waterbodies, i.e., hard waters with a range of 7.8 to 8.6. In all water types tested, however, ranging from very soft to very hard, considerable mussel kill was achieved (83 to 99% mean mortality), suggesting that regardless of the pH or hardness of the treated water, significant mussel kill can be achieved upon treatment with P. fluorescens strain CL0145A. These results further support the concept that this bacterium has significant potential for use as a zebra mussel control agent in power plant pipes receiving waters with a wide range of physical and chemical characteristics

  17. Traceability of pH to the Mole

    OpenAIRE

    Maria Filomena Camões; Bárbara Anes

    2015-01-01

    Free acidity of aqueous solutions was initially defined in 1909 by Søren Peter Lauritz Sørensen as pH = −lgcH+ (c/mol·dm−3 or m/mol·kg−1 of the free hydrogen ions in solution, H+) soon (1910) was changed to pH = paH+ = −lgaH+, integrating the new concepts of activity, ai and activity coefficient γi, for the ionic species i under concern, H+ in this case; it is ai = −lg(miγi). Since individual ions do not exist alone in solution, primary pH values cannot be assigned solely by experimental me...

  18. Intracellular pH in rat pancreatic ducts

    DEFF Research Database (Denmark)

    Novak, I; Hug, M; Greger, R

    1997-01-01

    buffers (20 mmol/l) led to pHi changes in accordance with entry of lipid-soluble forms of the buffers, followed by back-regulation of pHi by duct cells. In another type of experiment, changes in extracellular pH of solutions containing HEPES or HCO3-/CO2 buffers led to significant changes in pHi that did......In order to study the mechanism of H+ and HCO3- transport in a HCO3- secreting epithelium, pancreatic ducts, we have measured the intracellular pH (pHi) in this tissue using the pH sensitive probe BCECF. We found that exposures of ducts to solutions containing acetate/acetic acid or NH4+/NH3...

  19. PH and Electrochemical Responsive Materials for Corrosion Smart Coating Applications

    Science.gov (United States)

    Li, Wenyan; Calle, Luz M.

    2008-01-01

    Corrosion is a costly issue for military operations and civil industries. While most corrosion initiates from localized corrosion form, such as pitting, failure directly caused by localized corrosion is the most dangerous kind, because it is difficult to anticipate and prevent, occurs very suddenly and can be catastrophic. One way of preventing these failures is with a coating that can detect and heal localized corrosion. pH and other electrochemical changes are often associated with localized corrosion, so it is expected that materials that are pH or otherwise electrochemical responsive can be used to detect and control corrosion. This paper will review various pH and electrochemical responsive materials and their potential applications in corrosion smart coatings. Current research results in this field will also be reported.

  20. Stabilization of Mercury in High pH Tank Sludges

    Energy Technology Data Exchange (ETDEWEB)

    Spence, R.; Barton, J.

    2003-02-24

    DOE complex contains many tank sludges contaminated with mercury. The high pH of these tank sludges typically fails to stabilize the mercury, resulting in these radioactive wastes also being characteristically hazardous or mixed waste. The traditional treatment for soluble inorganic mercury species is precipitation as insoluble mercuric sulfide. Sulfide treatment and a commercial mercury-stabilizing product were tested on surrogate sludges at various alkaline pH values. Neither the sulfide nor the commercial product stabilized the mercury sufficiently at the high pH of the tank sludges to pass the Toxicity Characteristic Leach Procedure (TCLP) treatment standards of the Resource Conservation and Recovery Act (RCRA). The commercial product also failed to stabilize the mercury in samples of the actual tank sludges.