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Sample records for dos precursores polimericos

  1. Summary of ceramic pigments by polymer precursors Pechini method; Sintese de pigmentos ceramicos pelo metodo dos precursores polimericos

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    Silva, E.M. da; Galvao, S.B.; Paskocimas, C.A., E-mail: everlania_siva@yahoo.com.b [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2010-07-01

    In this work were synthesized nitrate chromium nitrate and iron-doped titanium oxide by the polymeric precursor method, for application as ceramic pigments. The stains were developed between the temperatures 700 deg C to 1000 deg C, in green for chromium oxide and orange for iron. Noticing an increase of its opacity by increasing temperature. Characterization by thermogravimetry (TG) showed strong thermo decomposition from 355 deg C for the chromium oxide and thermo decomposition gradual for the iron. By analysis of X-ray diffraction revealed the formation of crystalline phases as Iron Titanate (FeTiO3) and Chrome Titanate (CrTiO3), respectively. The scanning electron microscopy showed the formation of rounded particles for both oxides. Thus, the synthesized oxides were within the requirements to be applied as pigments and shown to be possible to propose its use in ceramic materials. (author)

  2. Silicon dioxide obtained by Polymeric Precursor Method; Obtencao de dioxido de silicio pelo Metodo dos Precursores Polimericos

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    Oliveira, C.T.; Granado, S.R.; Lopes, S.A.; Cavalheiro, A.A., E-mail: cinthia_quimica@hotmail.com [Universidade Estadual de Mato Grosso do Sul (CPTREN/UEMS), Navirai, MS (Brazil). Centro de Pesquisas Tecnologicas em Recursos Naturais

    2011-07-01

    The Polymeric Precursor Method is able for obtaining several oxide material types with high surface area even obtained in particle form. Several MO{sub 2} oxide types such as titanium, silicon and zirconium ones can be obtained by this methodology. In this work, the synthesis of silicon oxide was monitored by thermal analysis, XRD and surface area analysis in order to demonstrate the influence of the several synthesis and calcining parameters. Surface area values as higher as 370m2/g and increasing in the micropore volume nm were obtained when the material was synthesized by using ethylene glycol as polymerizing agent. XRD analysis showed that the material is amorphous when calcinated at 600°C in despite of the time of calcining, but the material morphology is strongly influenced by the polymeric resin composition. Using Glycerol as polymerizing agent, the pore size increase and the surface area goes down with the increasing in decomposition time, when compared to ethylene glycol. (author)

  3. Synthesis of encapsulated pigments based on Fe, Co and Si by route of polymeric precursors; Sintese de pigmentos encapsulados a base de Fe, Co e Si pela rota dos precursores polimericos

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    Macedo, D.S.S.M.; Macedo Neto, O.C.; Paskocimas, C.A. [Universidade Federal do Rio Grande do Norte (UFRN), RN (Brazil); Varela, M.L.N. [Instituto Federal do Rio Grande do Norte (IFRN), RN (Brazil)

    2012-07-01

    The objective is to apply the polymeric precursor method to obtain encapsulated pigments, the basis of oxides of iron and cobalt deposited on silica. The method has advantages such as reduction of time and reproducibility in the conventional methods, and also improves optical properties, thermal stability and morphology. The synthesis was based on the dissolution of the citric acid (complexing agent), addition of oxides of iron and cobalt (ions chromophores) polymerization of ethylene glycol and silica coating. The mixture was pre-calcined to form the precursor powder was analyzed by TG and DTA. Was then split, and calcined at different temperatures (700 ° C - 900 ° C) and analyzed by BET, DRX, MEV and UV-Visible. The pigments were stable thermally, with surface area ranging between 3,09 and 7,65 m² / g, formation of crystalline phases of cobalt ferrite (CoFe{sub 2}O{sub 4}) and Cristobalite (SiO{sub 2}) and agglomerates of particles slightly rounded. (author)

  4. Chemical synthesis of lithium meta-niobate Li Nb O{sub 3} by the polymeric precursor method; Sintese quimica do metaniobato de litio Li Nb O{sub 3} pelo metodo dos precursores polimericos

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    Ribeiro, M.D.; Leite, E.; Nobre, M.A.L. [Sao Carlos Univ., SP (Brazil). Dept. de Quimica; Varela, J.A. [UNESP, Araraquara, SP (Brazil). Inst. de Fisio-Quimica

    1996-09-01

    Lithium meta niobates Li Nb O{sub 3} (L N) show interesting properties with several technological application, such as: piezoelectric and electrooptic. The L N phase synthesized by traditional ceramic process lead to powders with low sinterability and low stoichiometric control due to the high calcination temperature (approx 1000 deg C). In this work, the L N phase was synthesized by polymeric precursor method. The phase formation was studied and characterized by X-ray diffraction (XRD) and differential thermal analysis (DTA). The results showed high crystallization at 500 deg C for short calcination time (0,5 h). The powder morphology analysis showed high surface area (20 m{sup 2}/g). (author) 13 refs., 6 figs.

  5. Effect of the calcining temperature on the porosity of the titanium dioxide powders obtained by Polymeric Precursor Method; Efeito da temperatura de calcinacao na porosidade de pos de dioxido de titanio obtidos pelo Metodo dos Precursores Polimericos

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    Silva, D.W.; Granado, S.R.; Ciola, R.A.; Cavalheiro, A.A., E-mail: douglas_levis@hotmail.com [Universidade Estadual de Mato Grosso do Sul (CPTREN/UEMS), Navirai, MS (Brazil). Centro de Pesquisas Tecnologicas em Recursos Naturais

    2011-07-01

    Ceramics materials obtained by Polymeric Precursor Method exhibit mechanisms of the pore formation and elimination dependents on the decomposition kinetics of the residual organic matter of the polyester. The mechanism of pore elimination seems to occur by disrupting of the wall among the pores because it leads to the consequent pore coalescence and increasing in pore volume, which posses higher pore diameters. In this case, it was observed that the porosity decreasing occurs by pore wall moving after that the residual organic matter is eliminated from the pore inside. The pore diameter associated to the highest volume desorption occurred for the material obtained after calcining at 450°C is approximately 1,7 nm, what seems to be related to the amorphous carbon accumulated inside the pores, once that the pore volume decreases more effectively for the material obtained by calcining at 550°C, making the maximum volume situates at 2,0 nm. (author)

  6. Synthesis and characterization of SnO2 doped with fluorine by the technique of polymeric precursors; Sintese e caracterizacao de SnO2 dopado com fluor pela tecnica dos precursores polimericos

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    Pereira, Gilberto J.; Lopes, Rafael Ialago, E-mail: gilbertop@fei.edu.br [Centro Universitario FEI, Sao Bernardo do Campo, SP (Brazil). Departamento de Engenharia de Materiais

    2016-07-01

    The present work deals with the synthesis of tin dioxide powders doped with fluorine and chlorine anions to evaluate the influence of these on the physico-chemical properties of SnO2, as well as to verify if the dopant does not make a solid solution with the material and its possible use as sintering additive. The samples were synthesized by Pechini method (polymer precursors) with tin oxalate as a source not contaminated with chlorine of this metal. Specific surface area characterization (BET method) and X-ray diffractometry (XRD) show that doping reduces the particle size of SnO2, being more effective at lower dopant levels. The dilatometry of the doped powders shows a reduction in the beginning and end temperatures of the sintering of the tin dioxide when compared with values in the literature.

  7. Synthesis of aluminum oxide by the polymer precursor method (Pechini) in 4: 1 ratio of citric acid: metal cation: calcination temperature effect; Sintese do oxido de aluminio pelo metodo dos precursores polimericos (Pechini) na relacao 4:1 de acido citrico: cation metalico: efeito da temperatura de calcinacao

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    Silva, M.C.; Lira, H.L.; Ribeiro, P.C.; Freitas, N.L., E-mail: mirelecsilva@hotmail.com [Universidade Federal de Campina Grande (UFCG), PB (Brazil). Unidade Academica de Engenharia de Materiais

    2014-07-01

    The technology field is nanopowders prominent in science since these materials fall in various sectors regarding their applications. This work aims at the synthesis of aluminum oxide by polymeric precursors in 4:1 ratio of citric acid:metal cation and evaluate the influence of calcination temperature on their structural and morphological characteristics. The samples after reaction were characterized by XRD and thermal analysis. After calcination 500-1200°C the samples were characterized by XRD, SEM and particle size distribution. The results showed that the variation of the calcination temperature is sufficient to achieve a same material with different structural and morphological characteristics. The most stable phase aluminum oxide arose only after calcination at 1100°C, below 900°C, the amorphous material appeared. As regards the morphology, the change was not as significant as compared to the structure. (author)

  8. Polymeric precursors method for obtaining pigments based on Inorganic oxides of chromium and iron deposited on TiO{sub 2}; Metodo dos precursores polimericos para obtencao de pigmentos inorganicos a base de oxidos de cromo e de ferro, depositados sobre TiO{sub 2}

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    NONE

    2011-07-01

    The case study was the use of chromium oxides and iron, as a precursor in the synthesis of inorganic pigments. The synthesis was based on the dissolution of citric acid as a complexing agent, addition of metal oxides, such as ion chromophores; polymerization with ethylene glycol and doping with titanium oxide. Going through pre-calcination, breakdown, calcination at different temperatures (700, 900 and 1100 deg C resulting in pigments: green for pigment and chromium deposited on TiO2, orange for iron on TiO2. The thermal analysis (TG and DTA), evaluated their thermal decompositions, the XRD revealed the formation of crystalline phases such as iron titanate and chrome titanate; SEM showed the formation of hexagonal particles for both oxides. Under the different analysis, one can see the potential stability of pigments and powders, can be proposed its use as pigments in polymers. (author)

  9. Structural and morphological characterization of TiO{sub 2}-ZrO{sub 2} powders obtained by the polymeric precursors method; Caracterizacao estrutural e morfologica de pos de TiO{sub 2}-ZrO{sub 2} obtidos pelo metodo dos precursores polimericos

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    Ribeiro, M.A.; Gama, L.; Bispo, A.; Neiva, L.S., E-mail: m_aparecidaribeiro@yahoo.com.b [Universidade Federal de Campina Grande (DEMa/UFCG), PB (Brazil). Dept. de Engenharia de Materiais; Bernardi, M.I.B. [Universidade de Sao Paulo (IFSC/USP), Sao Carlos, SP (Brazil). Inst. de Fisica; Kiminami, R.H.G.A. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais

    2010-07-01

    This work aims to characterize the structure and morphology of TiO{sub 2}-ZrO{sub 2} powders obtained by polymeric precursor method. For this we studied the following compositions: 0.25, 0.5 and 0.75 moles of Zr and calcined at 800 deg C for one hour. The powders obtained were characterized by XRD, SEM and nitrogen adsorption (BET). The analysis of X-ray diffraction showed that the powders had a phase of TiO{sub 2} in the anatase form and a tetragonal phase of ZrO{sub 2}. The crystallite size was between 8, 13 and 11 nm respectively. The analysis of scanning electron microscopy showed the growth of ZrO{sub 2} nanoparticles and that these comprise spherical agglomerates of less than 100 nm. Particle size determined by the BET ranging 28.1-29.5 nm, showing thereby the character of nanosized powders. (author)

  10. Comparative study of perovskites obtained by using polymeric precursors with composition La{sub 0,6}Ca{sub 0,4}(Co, Mn)O{sub 3} for use in combustion catalysis; Estudo comparativo de perovsquitas obtidas pelo metodo dos precursores polimericos com composicao La{sub 0,6}Ca{sub 0,4}(Co, Mn)O{sub 3} para utilizacao em catalise de combustao

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    Paiva, Ana Karenina de Oliveira; Wanderley, Jose Bruno de Moura; Batista, Jonathan Jalles Silva; Borges, Filipe Martel de Magalhaes; Melo, Dulce Maria de Araujo, E-mail: kareninapaiva@hotmail.com [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

    2012-07-01

    Materials with the perovskite structure are potential catalysts to reduce emissions of pollutants components into the environment. In the synthesis of perovskites, several methods have been proposed. In this work, lanthanum manganate compositions and lanthanum cobaltate with partial substitution of calcium (La{sub 0.6}Ca{sub 0.4}MnO{sub 3} and La{sub 0.6}Ca{sub 0.4}CoO{sub 3}, respectively), were synthesized using the polymeric precursor method. The powders obtained after 4h at 300° C (5° C/min), were calcined at temperatures of 700 and 900° C for 4 h (10° C/min), and characterized by X-ray Diffraction and Scanning Electron Microscopy. Comparing the X-ray Diffraction of the compositions manganate and lanthanum cobaltate, as the temperature increases, there is an increase in crystallinity, even more evident in manganate. TG curves showed similar thermal stabilities, with greater weight loss for the material cobaltate. The perovskites obtained were single phased, nanometric and had good porosity, making these potential catalysts appropriate properties for application in combustion reactions (author)

  11. TiO2 sintetizado por el método de precursor polimerico (Pechini: estructura de la resina intermedia

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    Rodriguez Paez, J. E.

    2011-10-01

    Full Text Available In this work, the polymeric precursor method (Pechini method was used to synthesize titanium dioxide. This process allowed a bigger control on the purity of the oxide and the crystalline phase present in the material. In this case, the principal phase was anatase. The resine obtained in this process was characterized using NMR and IR spectroscopy to determine their structure. With this information we proposed a resine structure model. To finish the process, the resin was thermally treated to obtain TiO2. This oxide was characterized using different techniques: ray-X diffraction (RDX and electron microscopy (TEM and SEM. The results indicated that the TiO2 anatase phase can be obtained at 450ºC with a particle size En este trabajo se ha utilizado el método de precursor polimérico (método de Pechini para sintetizar dióxido de titanio, proceso que ha permitido tener un mayor control sobre la pureza del óxido y el tipo de fase que ha presentado el material obtenido, fase anatasa en el presente caso. Durante el proceso de síntesis se ha obtenido una resina que se ha caracterizado utilizando la espectroscopia de Resonancia Magnética Nuclear (RMN y la espectroscopia infrarroja con transformada de Fourier (FTIR para determinar su estructura y con base en ella se ha propuesto un modelo para la conformación de la misma. Posteriormente esta resina se ha sometido a un tratamiento térmico para obtener los polvos cerámicos que se han caracterizado empleando diferentes técnicas, principalmente, difracción de rayos X (DRX y microscopia electrónica (MET y MEB. Los resultados indican que se puede obtener TiO2 fase anatasa a los 450ºC con un tamaño de partícula < 100nm.

  12. TiO{sub 2} synthesized by the method of polymeric precursor (Pechini): structure of the intermediate resine; TiO{sub 2} sintetizado por el metodo de precursor polimerico (Pechini): estructura de la resina intermedia

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    Vargas, M. A.; Granco, Y.; Ochoa, Y.; Ortegon, Y.; Rodriguez Paez, J. E.

    2011-07-01

    In this work, the polymeric precursor method (Pechini method) was used to synthesize titanium dioxide. This process allowed a bigger control on the purity of the oxide and the crystalline phase present in the material. In this case, the principal phase was anatase. The resine obtained in this process was characterized using NMR and IR spectroscopy to determine their structure. With this information we proposed a resine structure model. To finish the process, the resin was thermally treated to obtain TiO{sub 2}. This oxide was characterized using different techniques: ray-X diffraction (RDX) and electron microscopy (TEM and SEM). The results indicated that the TiO{sub 2} anatase phase can be obtained at 450 degree centigrade with a particle size <100nm. (Author) 10 refs.

  13. Characterization of dental cement obtained from a glass prepared by the polymeric precursor method; Caracterizacao de cimento odontologico obtido a partir de um vidro preparado pelo metodo dos precursores polimericos

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    Bertolini, Marcio Jose; Zaghete, Maria Aparecida; Gimenes, Rossano; Paiva-Santos, Carlos de Oliveira [UNESP, Araraquara, SP (Brazil). Inst. de Quimica]. E-mail: marciobert@yahoo.com.br; Palma-Dibb, Regina Guenka [Sao Paulo Univ., Ribeirao Preto, SP (Brazil). Faculdade de Odontologia

    2005-09-15

    Glass ionomer cements are glass and polymer composite materials. These materials currently find use in dentistry. The purpose of this work is to obtain glass powders based on the composition 4.5SiO{sub 2} - 3Al{sub 2}O{sub 3} - 2CaO to be used in dentistry. The powders were prepared by a chemical route at 700 deg C. The properties of glass ionomer cements obtained from powders prepared at 700 deg C were studied. Diametral tensile strength and microhardness were evaluated for the experimental glass ionomer cements and a commercial material. It was concluded that the properties of experimental cements were similar to those of the commercial ones. (author)

  14. Rotas de síntese e a homogeneidade dos precursores de mulita e cordierita Routes of synthesis and the homogeneity of mullite and cordierite precursors

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    Patrícia Tavares de Lima

    1998-10-01

    Full Text Available Multicomponent ceramics are mainly synthesized by conventional solid-state reaction route and sol-gel routes. In the sol-gel route, colloidal or polymeric gel are envolved. In this work, some principles of the chemistry of theses routes are discused and it is ilustrated a variety of strategies for obtaining a homogeneous multicomponent precursors.

  15. Atividade alelopática de chalcona sintética, de seus precursores e de cetonas e aldeídos relacionados Allelopathic activity of synthetic chalcone, its precursors and of related cetones and aldehydes

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    H.R. Bitencourt

    2007-12-01

    Full Text Available Vários metabólitos produzidos por plantas apresentam atividade herbicida. Essa característica tem levado à possibilidade de utilizar essas substâncias como herbicidas mais integrados às atuais exigências da sociedade. Entretanto, a obtenção dessas moléculas apresenta várias limitações, sendo, dessa forma, a síntese uma alternativa. Este trabalho teve por objetivo determinar as variações na atividade alelopática da chalcona, 2,4'-dimetoxichalcona, em função dos precursores, ortoanisaldeído e 4-metoxiacetofenona, e de alterações nestes. Os bioensaios foram monitorados em condições controladas de 25 ºC e fotoperíodo de 12 horas. Como plantas-teste foram utilizadas as plantas daninhas malícia (Mimosa pudica e mata-pasto (Senna obtusifolia. A atividade alelopática foi analisada em concentrações fixas de 100, 200 e 300 mg L-1. A chalcona foi obtida via reação de condensação entre a 4-metoxiacetofenona e o ortoanisaldeído. Os resultados indicaram que a atividade alelopática está relacionada, em princípio, ao precursor A, 4-metoxiacetofenona. Mudanças nos precursores indicaram a possibilidade de aumentar a atividade alelopática, em especial no precursor A. Ausência do grupo CH3O propiciou redução na atividade alelopática, indicando ser importante para a atividade. A presença de dois grupamentos OCH3 no precursor da porção B da chalcona aumentou para 62% a atividade do aldeído. Esses resultados indicam que alterações de substâncias com atividades alelopáticas são uma possível via para enfrentar os problemas atrelados aos processos de isolamento e identificação de moléculas químicas com atividade alelopática, em espécies de plantas.Several secondary metabolites produced by plants can be used as herbicides. These products are expected to offer fewer risks to the environment and to meet social demands. However, the availability of compounds is very limited, so synthesis is an alternative. The

  16. Estudos dos compostos orgânicos voláteis precursores de ozônio na cidade de São Paulo Studies of the volatile organic compounds precursors of ozone in São Paulo city

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    Débora Souza Alvim

    2011-06-01

    Full Text Available O ozônio é o principal problema de poluição do ar na cidade de São Paulo. Este estudo, que foi realizado em uma estação de monitoramento da qualidade do ar da Companhia de Tecnologia de Saneamento Ambiental (CETESB, enfoca a elucidação dos principais compostos orgânicos voláteis precursores de ozônio na atmosfera paulistana. Foram coletadas 36 amostras nos meses de agosto e setembro de 2006, nos quais o consumo de etanol era de aproximadamente 50% nesta época. Foram quantificadas 69 espécies de compostos orgânicos voláteis, nos quais os dez compostos mais importantes na formação de O3 foram: 1-buteno (6,8%, eteno (6,5%, formaldeído (6,1%, acetaldeído (5,5%, tolueno (4,8%, 1-etil-4-metilbenzeno (3,7%, trans-2-penteno (3,7%, propeno (3,7%, trans-2-buteno (3,5% e 1-metilciclopenteno (3,5%. As classes mais abundantes em concentração no ar foram: alcanos (45%, alcenos (26%, aromáticos (14%, aldeídos (13% e alcadienos (2%.Ozone is the main problem of air pollution in the city of São Paulo. This study, which was carried out in the Brazilian Basic Sanitation Engineering Company (CETESB, acronym in Portuguese monitoring station of air quality, focused on the elucidation of the main volatile organic compounds ozone precursors in São Paulo atmosphere. Thirty-six samples were collected in August and September 2006, when the consumption of ethanol was about 50%, 69 species of volatile organic compounds were quantified, the ten major urban pollutants compounds in the formation of O3 were: 1-butene (6.8%, ethylene (6.5%, formaldehyde (6.1%, acetaldehyde (5.5%, toluene (4.8%, 1-ethyl-4-methylbenzene (3.7%, trans-2-pentene (3.7%, propylene (3.7%, trans-2-butene (3.5%, and 1-methylcyclopentene (3.5%. The most abundant classes of air concentration were: alkanes (45%, alkenes (26%, aromatics (14%, aldehydes (13%, and alkadyenes (2%.

  17. SÍNTESE E CARACTERIZAÇÃO DE COBALTITA DE NIQUEL (NiCo2O4 OBTIDAS PELO MÉTODO DOS PRECURSORES POLIMÉRICOS

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    Marcelo Moizinho Oliveira

    2016-04-01

    Full Text Available A cobaltita de níquel NiCo2O4 de estrutura do tipo espinélia e suas soluções sólidas (NixCo1-xO4, tem sido amplamente utilizadas em materiais para armazenamento eletrônico de informação, catodo de baterias recargáveis de lítio, termistores, sensores de gás, eletrocatálise e supercapacitores, devido a sua elevada condutividade elétrica e propriedades antiferromagnéticas. Entretanto este material apresenta baixa estabilidade térmica em torno dos 400 °C, que ocasiona a perda de NiO, afetando de maneira significativa as propriedades físicas e estruturais do material produzido. Poucos trabalhos na literatura abordam procedimentos adequados para sua obtenção desse material sem a presença de fases cristalinas secundárias. Neste trabalho a cobaltita de níquel (NiCo2O4, foi preparada pelo método dos precursores poliméricos numa razão mássica de 60/40 entre o agente quelante (ácido cítrico e o polimerizante (etilenoglicol. O gel polimérico obtido foi calcinado a 350 °C para a eliminação do material orgânico e em seguida tratado termicamente às temperaturas de 450 °C, 550 °C e 750 °C. Os materiais obtidos foram caracterizados por TG/DSC, Difração de raios X (DRX, Refinamento Rietveld e Espectroscopia Raman. Os resultados mostraram que é possível se obter a fase cobaltita de níquel (NiCo2O4 independente do tratamento térmico empregado.

  18. Obtenção de filmes finos de TiO2 nanoestruturado pelo método dos precursores poliméricos Nanostructured TiO2 thin films by polymeric precursor method

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    Daniel Grando Stroppa

    2008-01-01

    Full Text Available This work focuses in optimizing setup for obtaining TiO2 thin films by polymeric precursor route due to its advantages on stoichiometric and morphological control. Precursor stoichiometry, synthesis pH, solids concentration and rotation speed at deposition were optimized evaluating thin films morphology and thickness. Thermogravimetry and RMN were applied for precursor's characterization and AFM, XRD and ellipsometry for thin films evaluation. Results showed successful attainment of homogeneous nanocrystalline anatase TiO2 thin films with outstanding control over morphological characteristics, mean grain size of 17 nm, packing densities between 57 and 75%, estimated surface areas of 90 m²/g and monolayers thickness within 20 and 128 nm.

  19. EFECTO DEL CONTENIDO DE SODIO EN LA OBTENCIÓN DE Na+ -B-ALÚMINA UTILIZANDO EL MÉTODO DE PRECURSOR POLIMÉRICO

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    VANESSA RUIZ

    2011-01-01

    Full Text Available En este trabajo se muestran los resultados obtenidos al emplear el metodo de precursor polimerico (Pechini para sintetizar polvos ceramicos de Na + B Àalumina, utilizando sales inorganicas, tomando como parametro de estudio la cantidad inicial del precursor de sodio y su efecto sobre la fase cristalina obtenida al final del proceso. Los polvos fueron caracterizados utilizando espectroscopia Infrarroja (FTIR, Difraccion de Rayos X (DRX y Microscopia Electronica de Barrido (MEB. Se encontro que el efecto de la cantidad de sodio inicial en la muestra es determinante en la naturaleza del producto final obtenido. Utilizando la cantidad estequiometrica de NaOH requerida, para la obtencion del compuesto NaAl11O17, se obtuvo al final del proceso (1450oC a-alumina y B-alumina y/o Na2Al2xO3x1 en muestras tratadas termicamente entre 1000oC y 1350oC. Cuando se uso una mayor cantidad de NaOH, muestra no estequiometrica, se obtuvo un solido con el compuesto NaAl11O17 como fase mayoritaria.

  20. Estudo da influência das condições de síntese do método dos precursores poliméricos na formação de perovsquitas do tipo LaNiO3 Study of the influence of the synthesis conditions of the precursor polymeric method for LaNiO3 perovskite type formation

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    M. C. Alves

    2011-09-01

    Full Text Available A perovsquita do tipo LaNiO3 é um material que exibe aplicações em diversas áreas como catálise, óptica, células a combustível de óxido sólido, etc.. Neste trabalho, a otimização da síntese de perovsquitas do tipo LaNiO3 foi feita pelo método dos precursores poliméricos, modificando as razões metal/ácido cítrico e etilenoglicol/ácido cítrico. Em geral, as propriedades destes materiais variam com a composição e com o método de síntese. Os materiais sintetizados foram caracterizados por difração de raios X, análise termogravimétrica e espectroscopia de infravermelho. As perovsquitas com razões metal/ácido cítrico (1,0/1,0 e etilenoglicol/ácido cítrico (60/40 apresentaram melhores resultados em relação à obtenção da fase perovsquita monofásica.The LaNiO3 perovskite is a material that displays applications in several areas as catalysis, optics, in solid oxide fuel cells, etc. In this work the optimization of the synthesis of LaNiO3 perovskite was performed using the polymeric precursor method, modifying the metal/citric acid and ethyleneglycol/citric acid ratios. In general, the properties of these materials vary with the composition and the synthesis method. The materials were characterized by X-ray diffraction, thermal gravimetric analysis and Fourier transform infrared spectroscopy. The perovskite with ratios metal/citric acid (1.0/1.0 and ethylene glycol/citric acid (60/40 showed better results to obtain the perovskite monophasic phase.

  1. Caracterização superficial de nanopartículas de BaTiO3 preparado pelo método dos precursores poliméricos Surface characterization of BaTiO3 nanoparticles prepared by the polymeric precursor method

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    S. L. M. Brito

    2010-07-01

    Full Text Available A síntese de nanopartículas e a sua caracterização têm sido a grande mola propulsora do desenvolvimento de materiais nano-estruturados. Pouca atenção tem sido dedicada aos fenômenos físico-químicos relacionados às enormes superfícies intrínsecas destes materiais. Dentre eles, o titanato de bário ocupa uma posição de destaque devido ao seu grande potencial na geração de produtos de alta tecnologia. Neste estudo o BaTiO3 foi sintetizado pelo método dos precursores poliméricos, que proporciona a geração de nanopartículas de grande uniformidade química. Contudo, o uso de cátions que formam carbonatos de alta estabilidade pode inviabilizar o uso do método. Os pós de titanato de bário preparados apresentaram elevada área de superfície específica, porém com formação de fases parasitas de carbonato de bário e carbonatos adsorvidos na superfície do titanato de bário. O estudo da química de superfície utilizando métodos como espectroscopia de infravermelho e análises eletrocinéticas permitiu a caracterização deste contaminante e demonstraram indícios de condições específicas de dissolução do carbonato de bário, que podem possibilitar a descontaminação do titanato de bário.The advance in new nanostructured materials technology is promoted by the development of new synthesis and characterization methods. The attention on the enormous specific surface area intrinsically associated to this material family and specifically on the physical-chemistry properties has been underestimated. BaTiO3 is an important material for producing ferroelectric ceramics and special attention is focused on the large potential offered by the properties of nanoparticles of this oxide. Our work proposes the understanding of the surface properties of BaTiO3 nanoparticles prepared by the polymeric precursor method. We dedicated a particular attention to the carbonates species formed during the polymeric precursor pyrolysis on the

  2. Evaluation by instrumented indentation of the damage caused by gamma radiation on polymeric materials; Avaliacao por indentacao instrumentada dos danos causados pela radiacao gama em materiais polimericos

    Energy Technology Data Exchange (ETDEWEB)

    Rosa, M.P.; Azevedo, E.C.; Miquelin, C.A.; Soboll, D.S., E-mail: helunica@yahoo.com.b [Universidade Tecnologica Federal do Parana (DAFIS/UTFPR), Curitiba, PR (Brazil). Dept. Academico de Fisica

    2010-07-01

    Several materials with densities close to water are used as phantoms in dosimetry. Such materials are damaged because they are exposed to radiation, the surface layers suffer the largest changes. This damage can be assessed by instrumented indentation. This paper investigates the variations in hardness and elastic modulus of samples of polymethyl-methacrylate, polyvinyl chloride, polyacetal and polypropylene before and after being irradiated with gamma radiation dose 500 Gy, using a Nanoindeter XP, with applied loads between 1 mN and 400 mN. The results are discussed correlating the variations in the mechanical properties of polymers with their applications. (author)

  3. Preparação de LiNbO3 e LiNbO3:Eu3+ pelo método dos precursores poliméricos

    Directory of Open Access Journals (Sweden)

    Souza Luciana A.

    2002-01-01

    Full Text Available The ferroelectric compound LiNbO3 was prepared by the polymeric precursors method in the polycrystalline form containing different concentrations of Eu3+. The compounds were characterized by X-ray diffraction, vibrational and electronic spectroscopy. Electronic spectroscopy was shown to be sensitive to small concentrations of contaminating phases allowing a good control of the compound purity. The presence of Eu3+ ions leads to the formation of the LiNb3O8 phase in the range of 500 to 800 degreesC. Above this temperature range LiNbO3 and tetragonal (T' EuNbO4 were obtained.

  4. Dos tiempos

    Directory of Open Access Journals (Sweden)

    Eduardo García Piedrahita

    1979-08-01

    Full Text Available Escena I: Un claro en la selva. En el fondo, un rancho de tierra y hojas. Suspendida de dos trozos de madera una hamaca. Troncos de árboles diseminados aquí y allá. Al lado de la puerta que da a la habitación, un fusil. Media tarde.

  5. Synthesis and characterization of CdS quantum dots stabilized with poly(vinyl alcohol): effect of molar fraction of precursors; Sintese e caracterizacao de pontos quanticos de CdS estabilizados com poli(alcool vinilico): efeito da fracao molar dos precursores

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    Semiconductor nanoparticles (quantum dots) with size lower than Bohr radius present quantum confinement effect, and properties dependent on particle diameter. The use of these nanoparticles for biological applications is highly promising, however this kind of use requires biocompatible systems. In this sense, the choice of poly(vinyl alcohol), PVA, as stabilizing agent has been investigated. The main goal of this work was synthesize and characterize CdS nanoparticles using PVA as capping agent varying the molar ratio of cadmium and sulfur precursors. The results revealed that absorption and emission properties, as well as nanoparticle size, were function of Cd/S ratio. (author)

  6. Fractal analysis of the electrical discharges' surface paths in polymeric insulation considering different pollution levels; Analisis fractal de las trayectorias de descargas electricas superficiales en aislamiento polimerico considerando diferentes niveles de contaminacion

    Energy Technology Data Exchange (ETDEWEB)

    Palacios Lopez, Arturo

    2002-07-01

    In this thesis tree patterns of superficial breakdown in polymeric insulator of Silicon Rubber are generated. Experimental arrangement rod-rod was used on the basis of norm ASTM D 2303-85. Pollution levels on the basis of norm IEC 507 were also used. The experimental values of Fractal Dimension for each case of pollution were reported. A self similar method called Box Counting for the fractal dimension calculus and for the self affine methods an R/S and Variogram were used. According to the results, it was concluded that the tree patterns of superficial electric breakdown in Silicon Rubber is self similar and its value does not depend on the degree of pollution, that is equivalent to the concentration of salt for liter of water or to the Equivalent Salt Deposition (ESDD), in the surface of an insulator. [Spanish] En el presente trabajo se inducen descargas electricas superficiales en un aislamiento polimerico de Hule Silicon, el arreglo experimental que se utilice es punta-punta con base en la norma ASTM D 2303-85 y los niveles de contaminacion con base en la norma IEC 507. Se reportan los valores experimentales de la Dimension Fractal para cada caso de contaminacion, se utilice el metodo auto similar de conteo de cuadros, para el calculo de la Dimension Fractal y para metodos auto afines se utilice analisis R/S y variograma. Con los resultados obtenidos se concluye que la trayectoria de la descarga electrica superficial en un polimero de Hule Silicon es auto similar y su valor no depende del grado de contaminacion, el cual es equivalente a la concentracion de gramos de sal por litro de agua o a la densidad de sal depositada (DESD), en la superficie de un aislador.

  7. Sonic Hedgehod y comportamiento de precursores neuroepiteliales

    OpenAIRE

    Santos Gutiérrez, Álvaro; Recio Moreno, Beatriz

    2016-01-01

    En los estadios tempranos del desarrollo embrionario, el cerebro tiene dos componentes fundamentales: fluido cerebroespinal embrionario (E-CSF) y precursores neuroepiteliales. En esta investigación nos centraremos en explicar la influencia de un factor de transcripción, sonic hedgehog (SHH), presente en el E-CSF, sobre el comportamiento de los precursores neuroepiteliares. Empleamos técnicas de Wester-Blot para demostrar la presencia de SHH en el E-CSF y técnicas de cultivo organotípico de...

  8. Dinâmica dos precursores celulares do epitélio olfatório de cães sem raça definida: um estudo imunohistoquímico e ultra-estrutural The dynamic of precursor of the olfactory epithelium of mongrel dogs: an immunohistochemical and ultrastructural study

    Directory of Open Access Journals (Sweden)

    Flávio Ribeiro Alves

    2007-09-01

    Full Text Available O epitélio olfatório apresenta um mecanismo de diferenciação em que células-tronco dão origem a células progenitoras amplificadoras, as quais expressam um gene pró-neural denominado Mammalian Achaete Scute Homolog 1 (Mash1. Estas células podem se diferenciar em receptores olfatórios. O epitélio olfatório de cães sem raça definida (3 machos de um ano e 2 fêmeas de três de idade foi analisado por imunolocalização do antígeno nuclear de proliferação celular (PCNA e por microscopia eletrônica de transmissão. Verificou-se marcação positiva para PCNA em células do epitélio olfatório, particularmente acima da linha da membrana basal. A ultra-estrutura do epitélio olfatório revelou células adjacentes à lâmina basal, cuja eletrodensidade assemelha-se àquelas presentes no epitélio de sustentação, reforçando a idéia da renovação das células de sustentação e dos neurônios olfatórios locais. O epitélio olfatório é composto células basais, comprometidas com sua renovação, caracterizadas através da intensa atividade mitótica, identificada pela reação positiva ao PCNA. Estes resultados sugerem que há reposição das células sustentaculares locais e do sistema através de mecanismos semelhantes.Olfactory epithelium presents a mechanism of differentiation where stem cells give arise to amplifying progenitor cell which express Mammalian Achaete Scute Homolog 1 (Mash1. These cells can be differentiated into olfactory receptors. An immunolocalization study and ultrastructural analysis by transmission electron microscopy of olfactory epithelium of mongrel dogs were made using 3 males (one year old and 2 females (three years old. Labeled cells with positive staining by Proliferating cell nuclear antigen (PCNA were observed in specific areas of the olfactory epithelium, especially above the basal membrane. The ultrastructure revealed cells adjacent to the basal membrane with morphology resembling sustentacular

  9. Earthquakes: hydrogeochemical precursors

    Science.gov (United States)

    Ingebritsen, Steven E.; Manga, Michael

    2014-01-01

    Earthquake prediction is a long-sought goal. Changes in groundwater chemistry before earthquakes in Iceland highlight a potential hydrogeochemical precursor, but such signals must be evaluated in the context of long-term, multiparametric data sets.

  10. Identification of Desirable Precursor Properties for Solution Precursor Plasma Spray

    Science.gov (United States)

    Muoto, Chigozie K.; Jordan, Eric H.; Gell, Maurice; Aindow, Mark

    2011-06-01

    In solution precursor plasma spray chemical precursor solutions are injected into a standard plasma torch and the final material is formed and deposited in a single step. This process has several attractive features, including the ability to rapidly explore new compositions and to form amorphous and metastable phases from molecularly mixed precursors. Challenges include: (a) moderate deposition rates due to the need to evaporate the precursor solvent, (b) dealing on a case by case basis with precursor characteristics that influence the spray process (viscosity, endothermic and exothermic reactions, the sequence of physical states through which the precursor passes before attaining the final state, etc.). Desirable precursor properties were identified by comparing an effective precursor for yttria-stabilized zirconia with four less effective candidate precursors for MgO:Y2O3. The critical parameters identified were a lack of major endothermic events during precursor decomposition and highly dense resultant particles.

  11. Characterization of Maytenus ilicifolia samples by {sup 1}H NMR relaxation in the solid state; Caracterizacao dos constituintes polimericos da Maytenus ilicifolia por relaxacao nuclear de {sup 1}H por RMN no estado solido

    Energy Technology Data Exchange (ETDEWEB)

    Preto, Monica S. de M.; Tavares, Maria I.B., E-mail: mibt@ima.ufrj.br [Universidade Federal do Rio de Janeiro (IMA/UFRJ), RJ (Brazil). Inst. de Macromoleculas Professora Eloisa Mano. Lab de Ressonancia Magnetica Nuclear; Sebastiao, Pedro J.O. [Departamento de Fisica, Instituto Superior Tecnico, Lisboa (Portugal)

    2011-07-01

    The Maytenus ilicifolia (espinheira-santa) is a popular medicinal plant with different uses. It is native of South America and can be found in Brazil. In the Brazilian market it is possible found products labeled as M. ilicifolia. So far, the studies published in the literature involve the modification of the natural materials and do not concern the comparison between commercial the raw natural materials. Different non-destructive NMR techniques can be used to study natural materials. In this work it is presented a characterization study by Fast Field Cycling of the {sup 1}H spin-lattice relaxation time (T{sub 1}) NMR, in the frequency range 100 khz-10 MHz. The results obtained in two commercial M. ilicifolia samples and one control sample collected in natura are compared. It was intended to study the possibility to elaborate a characterization method using FFCNMR suitable for the verification of authenticity and/or evaluation of tampering on products. The differences detected by FFCNMR relaxometry were confirmed by thermogravimetric analysis and infrared spectroscopy. (author)

  12. Lista dos estoicos antigos

    Directory of Open Access Journals (Sweden)

    Luís Márcio Fontes

    2016-03-01

    Full Text Available Lista dos antigos estoicos confeccionada nos seminários Viva Vox por Luís Márcio Fontes e Aldo Dinucci. Apresentada em formato banner, para fins didáticos, com o estabelecimento dos nomes de filósofos e personagens históricos antigos.

  13. Precursors of extreme increments

    CERN Document Server

    Hallerberg, S; Holstein, D; Kantz, H; Hallerberg, Sarah; Altmann, Eduardo G.; Holstein, Detlef; Kantz, Holger

    2006-01-01

    We investigate precursors and predictability of extreme events in time series, which consist in large increments within successive time steps. In order to understand the predictability of this class of extreme events, we study analytically the prediction of extreme increments in AR(1)-processes. The resulting strategies are then applied to predict sudden increases in wind speed recordings. In both cases we evaluate the success of predictions via creating receiver operator characteristics (ROC-plots). Surprisingly, we obtain better ROC-plots for completely uncorrelated Gaussian random numbers than for AR(1)-correlated data. Furthermore, we observe an increase of predictability with increasing event size. Both effects can be understood by using the likelihood ratio as a summary index for smooth ROC-curves.

  14. Precursor flares in OJ 287

    OpenAIRE

    Pihajoki, P.; Valtonen, M.; Zola, S.; Liakos, A.; Drozdz, M.; Winiarski, M.; Ogloza, W.; Koziel-Wierzbowska, D.; Provencal, J.; Nilsson, K.; Berdyugin, A.; Lindfors, E.; Reinthal, R.; Sillanpää, A.; Takalo, L.

    2012-01-01

    We have studied three most recent precursor flares in the light curve of the blazar OJ 287 while invoking the presence of a precessing binary black hole in the system to explain the nature of these flares. Precursor flare timings from the historical light curves are compared with theoretical predictions from our model that incorporate effects of an accretion disk and post-Newtonian description for the binary black hole orbit. We find that the precursor flares coincide with the secondary black...

  15. Generation of nonlinear vortex precursors

    CERN Document Server

    Chen, Yue-Yue; Liu, Chengpu

    2016-01-01

    We numerically study the propagation of a few-cycle pulse carrying orbital angular momentum (OAM) through a dense atomic system. Nonlinear precursors consisting of high-order vortex har- monics are generated in the transmitted field due to ultrafast Bloch oscillation. The nonlinear precursors survive to propagation effects and are well separated with the main pulse, which provide a straightforward way of measuring precursors. By the virtue of carrying high-order OAM, the obtained vortex precursors as information carriers have potential applications in optical informa- tion and communication fields where controllable loss, large information-carrying capacity and high speed communication are required.

  16. A cidade dos outros

    Directory of Open Access Journals (Sweden)

    Ernesto Venturini

    2009-08-01

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

  17. PRECURSOR FLARES IN OJ 287

    Energy Technology Data Exchange (ETDEWEB)

    Pihajoki, P.; Berdyugin, A.; Lindfors, E.; Reinthal, R.; Sillanpaeae, A.; Takalo, L. [Tuorla Observatory, Department of Physics and Astronomy, University of Turku, FI-21500 Piikkioe (Finland); Valtonen, M.; Nilsson, K. [Finnish Centre for Astronomy with ESO, University of Turku, FI-21500 Piikkioe (Finland); Zola, S.; Koziel-Wierzbowska, D. [Astronomical Observatory, Jagiellonian University, ul. Orla 171, PL-30-244 Krakow (Poland); Liakos, A. [Department of Astrophysics, Astronomy and Mechanics, University of Athens, GR 157 84 Zografos, Athens, Hellas (Greece); Drozdz, M.; Winiarski, M.; Ogloza, W. [Mount Suhora Observatory, Pedagogical University, ul. Podchorazych 2, PL-30-084 Krakow (Poland); Provencal, J. [Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Santangelo, M. M. M. [O.A.C. Osservatorio Astronomico di Capannori, Via di Valle, I-55060 Vorno, Capannori (Italy); Salo, H. [Department of Physical Sciences, University of Oulu, P.O. Box 3000, FI-90014 University of Oulu (Finland); Chandra, S.; Ganesh, S.; Baliyan, K. S., E-mail: popiha@utu.fi [Astronomy and Astrophysics Division, Physical Research Laboratory, Ahmedabad 380009 (India); and others

    2013-02-10

    We have studied three most recent precursor flares in the light curve of the blazar OJ 287 while invoking the presence of a precessing binary black hole in the system to explain the nature of these flares. Precursor flare timings from the historical light curves are compared with theoretical predictions from our model that incorporate effects of an accretion disk and post-Newtonian description for the binary black hole orbit. We find that the precursor flares coincide with the secondary black hole descending toward the accretion disk of the primary black hole from the observed side, with a mean z-component of approximately z{sub c} = 4000 AU. We use this model of precursor flares to predict that precursor flare of similar nature should happen around 2020.96 before the next major outburst in 2022.

  18. Conglomeración de precursores de tensión arterial elevada en adolescentes

    Directory of Open Access Journals (Sweden)

    Carlos M. Arango

    2014-09-01

    Conclusión: La conglomeración de dos o más precursores se asoció de manera significativa con la tensión arterial elevada, hallazgos que indican que se requieren intervenciones para reducir la presencia y acumulación de los precursores estudiados y así prevenir la adquisición de cifras de tensión arterial elevada en los adolescentes de Montería.

  19. Brillouin precursors in Debye media

    CERN Document Server

    Macke, Bruno

    2015-01-01

    We theoretically study the formation of Brillouin precursors in Debye media. We point out that the precursors are only visible at propagation distances such that the impulse response of the medium is essentially determined by the frequency-dependence of its absorption and is practically Gaussian. By simple convolution, we then obtain explicit analytical expressions of the transmitted waves generated by reference incident waves, distinguishing precursor and main signal by physical arguments. These expressions are in good agreement with the signals obtained in numerical or real experiments performed on water and explain some features of these signals that remained mysterious or unnoticed. In addition, we show quite generally that the shape of the Brillouin precursor appearing alone at large enough propagation distance and the law giving its amplitude as a function of this distance do not depend on the precise form of the incident wave but only on its integral properties. The incidence of a static conductivity o...

  20. O ecologismo dos pobres

    Directory of Open Access Journals (Sweden)

    Juan Martinez ALIER

    1997-12-01

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

  1. Dos cupas complutenses

    Directory of Open Access Journals (Sweden)

    Stylow, Armin U.

    2006-12-01

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

  2. Sustentabilidad a dos tiempos

    OpenAIRE

    Santiago Jiménez, María Evelinda

    2012-01-01

    Este trabajo revisa los hechos y documentos de organismos mundiales que conformaron el discurso del desarrollo sustentable. Así también, describe cómo el desarrollo sustentable cobra bajo dos lecturas o concepciones muy diferentes efectos, en la sociedad y en el planeta, muy distintos: una construida desde los conceptos desarrollistas y otra que construye un discurso alternativo que toma en cuenta las representaciones sociales y modos de producción de las comunidades originarias donde se hall...

  3. Geoeconomia dos emergentes

    OpenAIRE

    Pinto, Pedro

    2010-01-01

    Mercados decisivos para a recuperação da economia global, até porque muito mais imunes às consequências da crise fi nanceira, os países emergentes apresentam taxas de crescimento mais altas face aos principais países desenvolvidos e têm desempenhado um papel fundamental na consolidação dos volumes de comércio internacional e de crescimento da economia mundial ao longo desta última década.

  4. Trending analysis of precursor events

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Norio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-01-01

    The Accident Sequence Precursor (ASP) Program of United States Nuclear Regulatory Commission (U.S.NRC) identifies and categorizes operational events at nuclear power plants in terms of the potential for core damage. The ASP analysis has been performed on yearly basis and the results have been published in the annual reports. This paper describes the trends in initiating events and dominant sequences for 459 precursors identified in the ASP Program during the 1969-94 period and also discusses a comparison with dominant sequences predicted in the past Probabilistic Risk Assessment (PRA) studies. These trends were examined for three time periods, 1969-81, 1984-87 and 1988-94. Although the different models had been used in the ASP analyses for these three periods, the distribution of precursors by dominant sequences show similar trends to each other. For example, the sequences involving loss of both main and auxiliary feedwater were identified in many PWR events and those involving loss of both high and low coolant injection were found in many BWR events. Also, it was found that these dominant sequences were comparable to those determined to be dominant in the predictions by the past PRAs. As well, a list of the 459 precursors identified are provided in Appendix, indicating initiating event types, unavailable systems, dominant sequences, conditional core damage probabilities, and so on. (author)

  5. PAGOSA Sample Problem. Elastic Precursor

    Energy Technology Data Exchange (ETDEWEB)

    Weseloh, Wayne N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Clancy, Sean Patrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-02-03

    A PAGOSA simulation of a flyer plate impact which produces an elastic precursor wave is examined. The simulation is compared to an analytic theory for the Mie-Grüneisen equation of state and an elastic-perfectly-plastic strength model.

  6. The DosS-DosT/DosR Mycobacterial Sensor System

    Directory of Open Access Journals (Sweden)

    Santhosh Sivaramakrishnan

    2013-07-01

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

  7. Uma tipologia dos games

    Directory of Open Access Journals (Sweden)

    Branco, Marsal Alves

    2006-01-01

    Full Text Available Este artigo traz uma diferente concepção acerca da tipologia dos games. Partimos da concepção que narratologia e ludologia devem estar relacionadas, como já aponta Frasca, contudo, esta articulação ainda não dá conta de algumas especificidades dos games. A partir disso, propomos alguns movimentos: a existência de um conceito de narrativa específico que é formado pela ação de três diferentes dimensões; uma dimensão genérica ou de gênero narrativo propriamente dito; uma dimensão ludológica; e uma terceira dimensão, que é a dimensão tecnológica. This article presents a different conception concerning the tipology of games. We begin from the conception that narrative and ludology should be relates, as mentioned by frasca, however, this articulation hasn't given an account on some specificities of the game yet. From this, we propose some movements: The existence of a specific narrative concept which is formed by the action of three diferrent dimensions; a generic or narrative sort of dimension; a ludologic dimension; and a third dimension, which is the technological dimension.

  8. A Medicina dos Sintomas

    Directory of Open Access Journals (Sweden)

    Bárbara Bontempo de Menezes

    2015-09-01

    Full Text Available Gilson Dantas, médico e doutor em sociologia, aponta os vieses da prática médica atual na publicação «A Medicina dos Sintomas». O autor defende a tese de que o erro está no método, e não é à toa, nem por má vontade dos profissionais. Acima de tudo, o método praticado nos consultórios públicos e privados do país serviria ao capitalismo de várias maneiras. Dantas começa descrevendo o atendimento imediatista, que permite o pronto retorno do trabalhador a seu posto de trabalho. Nesta prática, prevalece uma abordagem rápida em que a comunicação é pautada puramente pelos sintomas. O paciente é reduzido a sua parte com problema ou até mesmo ao problema de sua parte. Promove-se o consumo de exames e prescreve-se a dependência de medicamentos, atendendo aos interesses de uma das indústrias mais lucrativas do mundo. Esse círculo se fecha com a produção de novos sintomas gerados pelos tratamentos químicos propostos (iatrogenia e, assim, novas demandas por serviços desse mesmo tipo.

  9. dos estudios de caso

    Directory of Open Access Journals (Sweden)

    Daniel Kersffeld

    2013-01-01

    Full Text Available La UNASUR se ha destacado desde sus inicios en la compleja labor de mediación y resolución de conflictos internacionales. Para ello, esta entidad multilateral ha apelado a distintas fórmulas políticas tendientes al encausamiento de problemáticas y conflictos apartados del camino de la institucionalidad y de los medios tradicionales de resolución. Con todo, y pese a la búsqueda de caminos alternativos, han sido las cumbres presidenciales la principal herramienta destinada a encontrar soluciones innovadoras y respetuosas del orden democrático y constitucional de los países sudamericanos. En este artículo se analiza de manera específica la actuación de la unasur en dos casos de profunda gravedad institucional: el intento de golpe de Estado ocurrido en Ecuador el 30 de septiembre de 2010 y el derrocamiento del ex presidente Fernando Lugo en Paraguay en junio de 2012. Luego de analizar estos dos casos extremos, y las implicancias políticas generadas, se avanza en una visión comprensiva acerca del éxito o el fracaso del papel político de la unasur como instancia de resolución de conflictos a nivel internacional.

  10. Dos estudios de casos

    Directory of Open Access Journals (Sweden)

    Hernán Guillermo Salazar Morales

    1989-04-01

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

  11. Precursor polymer compositions comprising polybenzimidazole

    Energy Technology Data Exchange (ETDEWEB)

    Klaehn, John R.; Peterson, Eric S.; Orme, Christopher J.

    2015-07-14

    Stable, high performance polymer compositions including polybenzimidazole (PBI) and a melamine-formaldehyde polymer, such as methylated, poly(melamine-co-formaldehyde), for forming structures such as films, fibers and bulky structures. The polymer compositions may be formed by combining polybenzimidazole with the melamine-formaldehyde polymer to form a precursor. The polybenzimidazole may be reacted and/or intertwined with the melamine-formaldehyde polymer to form the polymer composition. For example, a stable, free-standing film having a thickness of, for example, between about 5 .mu.m and about 30 .mu.m may be formed from the polymer composition. Such films may be used as gas separation membranes and may be submerged into water for extended periods without crazing and cracking. The polymer composition may also be used as a coating on substrates, such as metal and ceramics, or may be used for spinning fibers. Precursors for forming such polymer compositions are also disclosed.

  12. The Innate Lymphoid Cell Precursor.

    Science.gov (United States)

    Ishizuka, Isabel E; Constantinides, Michael G; Gudjonson, Herman; Bendelac, Albert

    2016-05-20

    The discovery of tissue-resident innate lymphoid cell populations effecting different forms of type 1, 2, and 3 immunity; tissue repair; and immune regulation has transformed our understanding of mucosal immunity and allergy. The emerging complexity of these populations along with compounding issues of redundancy and plasticity raise intriguing questions about their precise lineage relationship. Here we review advances in mapping the emergence of these lineages from early lymphoid precursors. We discuss the identification of a common innate lymphoid cell precursor characterized by transient expression of the transcription factor PLZF, and the lineage relationships of innate lymphoid cells with conventional natural killer cells and lymphoid tissue inducer cells. We also review the rapidly growing understanding of the network of transcription factors that direct the development of these lineages.

  13. Precursor polymer compositions comprising polybenzimidazole

    Science.gov (United States)

    Klaehn, John R.; Peterson, Eric S.; Orme, Christopher J.

    2015-07-14

    Stable, high performance polymer compositions including polybenzimidazole (PBI) and a melamine-formaldehyde polymer, such as methylated, poly(melamine-co-formaldehyde), for forming structures such as films, fibers and bulky structures. The polymer compositions may be formed by combining polybenzimidazole with the melamine-formaldehyde polymer to form a precursor. The polybenzimidazole may be reacted and/or intertwined with the melamine-formaldehyde polymer to form the polymer composition. For example, a stable, free-standing film having a thickness of, for example, between about 5 .mu.m and about 30 .mu.m may be formed from the polymer composition. Such films may be used as gas separation membranes and may be submerged into water for extended periods without crazing and cracking. The polymer composition may also be used as a coating on substrates, such as metal and ceramics, or may be used for spinning fibers. Precursors for forming such polymer compositions are also disclosed.

  14. Soluble Precursor Route to Polyanilines

    Science.gov (United States)

    1993-01-01

    condensation were not successful, but further work produced polymer under the following conditions: Synthesis Diketone I (2.40 g, 10.0 mmol) in 10 mL...goal of producing a processible form of the conducting polymer polyaniline (PANI), the Phase I program concentrated on development of the synthesis of...extension of the original research to a Phase II effort. Diketone - Diamine Polycondensation Towards a Soluble PAni Precursor To achieve the

  15. PKP precursors : Implications for global scatterers

    NARCIS (Netherlands)

    Waszek, Lauren; Thomas, Christine; Deuss, Arwen

    2015-01-01

    Precursors to the core phase PKP are generated by scattering of seismic energy from heterogeneities in the mantle. Here we examine a large global data set of PKP precursors in individual seismograms and array data, to better understand scattering locations. The precursor amplitudes from individual s

  16. Palavras dos editores

    Directory of Open Access Journals (Sweden)

    Nelkis de la Orden Medina

    2005-12-01

    Full Text Available Este número da revista RESI está sendo editado em conjunto por mim e pelo novo editor Jorge Muniz Barreto. A revista tem agora nova sede, o Departamento de Informática e de Estatística da Universidade Federal de Santa Catarina. No que a me diz respeito, tenho a satisfação após estes 4 anos de trabalho de ter contribuído no lançamento e consolidação da revista, a qual considero uma ferramenta útil no âmbito universitário. Agradeço a todos os que fizeram possível a realização deste projeto: aos membros do conselho editorial, ao corpo de avaliadores e principalmente aos autores de trabalhos publicados. Gostaria de agradecer ao novo editor sua excelente disposição para aceitar este desafio e lhe desejo uma gestão editorial de muito sucesso. Tenho a certeza que estamos iniciando uma nova etapa da revista que permitirá um crescimento maior da mesma, na qual continuaremos a colaborar de forma permanente. Campo Largo, dezembro de 2005. Nelkis de la Orden Medina, Editora-Chefe. Repletos de idealismo iniciamos com a edição 6 da Revista Eletrônica de Sistemas de Informação nossa atuação como Editor-Chefe. Esperamos honrar os sucessos obtidos pela revista nos cinco números anteriores, e tornar RESI, cada vez mais útil a seus leitores. Para isto temos planos e contamos além do Conselho Editorial e Revisores, ouvir também a opinião dos leitores de modo informal. Para isto criamos um MSN-Space onde os leitores poderão colocar suas sugestões (operacional e conhecer alguns membros tanto do conselho como revisores. Para vê-lo acessem:http://spaces.msn.com/members/resireveletron Os trabalhos apresentados dão continuidade ao estilo das edições anteriores. São seis artigos, abordando assuntos relacionados à Sistemas de Informação. Estes artigos enriquecem o acervo de trabalhos publicados na revista RESI e mostram o panorama das pesquisas que estão sendo desenvolvidas no Brasil e países amigos. Dentre os planos para o ano

  17. DOS cones along atomic chains

    Science.gov (United States)

    Kwapiński, Tomasz

    2017-03-01

    The electron transport properties of a linear atomic chain are studied theoretically within the tight-binding Hamiltonian and the Green’s function method. Variations of the local density of states (DOS) along the chain are investigated. They are crucial in scanning tunnelling experiments and give important insight into the electron transport mechanism and charge distribution inside chains. It is found that depending on the chain parity the local DOS at the Fermi level can form cone-like structures (DOS cones) along the chain. The general condition for the local DOS oscillations is obtained and the linear behaviour of the local density function is confirmed analytically. DOS cones are characterized by a linear decay towards the chain which is in contrast to the propagation properties of charge density waves, end states and Friedel oscillations in one-dimensional systems. We find that DOS cones can appear due to non-resonant electron transport, the spin–orbit scattering or for chains fabricated on a substrate with localized electrons. It is also shown that for imperfect chains (e.g. with a reduced coupling strength between two neighboring sites) a diamond-like structure of the local DOS along the chain appears.

  18. ANÁLISE DO CONTEÚDO INFORMATIVO DOS PARECERES DOS AUDITORES DOS TRIBUNAIS DE CONTAS DOS ESTADOS BRASILEIROS

    Directory of Open Access Journals (Sweden)

    Francisca Francivânia Rodrigues

    2014-09-01

    Full Text Available Este estudo objetiva descrever o conteúdo informativo dos pareceres prévios emitidos pelos auditores dos tribunais de contas dos estados brasileiros divulgados no período de 2008 a 2010. Para isso, realiza-se um estudo descritivo, com abordagem predominantemente qualitativa, por meio de pesquisa documental e análise de conteúdo, com consultas aos sites oficiais dos tribunais de contas estaduais. O universo da pesquisa corresponde às 27 unidades federativas do Brasil, excluídas aquelas que não possuíam nos sites oficiais de seus tribunais de contas todas as informações propostas para o estudo - tratando-se dos estados do Acre, Amapá, Rondônia, Roraima, Maranhão e Piauí -, resultando em uma amostra de 21 unidades federativas. Os resultados apontam que os tribunais de contas dos estados das regiões Centro-Oeste, Sudeste e Sul apresentaram maior assiduidade quanto à divulgação do parecer de auditoria nos seus sites. Verifica-se, também, que há inúmeras ordenações feitas pelos auditores aos órgãos públicos no que concerne à aplicação das normas referentes à contabilidade do setor público. Ao final, conclui-se que existem divergências no conteúdo informacional dos pareceres prévios dos tribunais de contas dos estados brasileiros, embora tratem de matéria similar. Vê-se, também, que os gestores públicos das unidades federativas do Brasil descumpriram, em alguns quesitos, a Lei nº 4.320/1964, a Lei nº 101/2000 e a Constituição Federal.

  19. Dos chalets, en Suecia

    Directory of Open Access Journals (Sweden)

    Erskine, Ralph

    1968-04-01

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

  20. Psicoterapia Psicodinâmica Breve: dos precursores aos modelos atuais

    OpenAIRE

    Oliveira,Iraní Tomiatto de

    2009-01-01

    O artigo apresenta uma visão panorâmica da psicoterapia psicodinâmica breve, desde sua origem até os dias atuais. Após a localização histórica de seu surgimento, faz referência aos modelos teóricos e técnicos mais utilizados nas últimas décadas e seus principais representantes. Inclui também algumas das principais contribuições à aplicação destas técnicas à população infantil.Palavras-chave: Psicoterapia Breve, Modelos de Psicoterapia Breve, Psicoterapia Breve de Crianças....

  1. Rapid synthesis of macrocycles from diol precursors

    DEFF Research Database (Denmark)

    Wingstrand, Magnus; Madsen, Charlotte Marie; Clausen, Mads Hartvig

    2009-01-01

    A method for the formation of synthetic macrocycles with different ring sizes from diols is presented. Reacting a simple diol precursor with electrophilic reagents leads to a cyclic carbonate, sulfite or phosphate in a single step in 25-60% yield. Converting the cyclization precursor to a bis-ele...

  2. The Interrelationships of Mathematical Precursors in Kindergarten

    Science.gov (United States)

    Cirino, Paul T.

    2011-01-01

    This study evaluated the interrelations among cognitive precursors across quantitative, linguistic, and spatial attention domains that have been implicated for math achievement in young children. The dimensionality of the quantity precursors was evaluated in 286 kindergarteners via latent variable techniques, and the contribution of precursors…

  3. Preparation of precursor for stainless steel foam

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xiang-yang; LI Shan-ni; LI Jie; LIU Ye-xiang

    2008-01-01

    The effects of polyurethane sponge pretreatment and slurry compositions on the slurry loading in precursor were discussed, and the,performances of stainless steel foams prepared from precursors with different slurry loadings and different particle sizes of the stainless steel powder were also investigated. The experimental results show that the pretreatment of sponge with alkaline solution is effective to reduce the jam of cells in precursor and ensure the slurry to uniformly distribute in sponge, and it is also an effective method for increasing the slurry loading in precursor; the mass fraction of additive A and solid content in slurry greatly affect the slurry loading in precursor, when they are kept in 9%-13% and 52%-75%, respectively, the stainless steel foam may hold excellent 3D open-cell network structure and uniform muscles; the particle size of the stainless steel powder and the slurry loading in precursor have great effects on the bending strength, apparent density and open porosity of stainless steel foam; when the stainless steel powder with particle size of 44 tan and slurry loading of 0.5 g/cm3 in precursor are used, a stainless steel foam can be obtained, which has open porosity of 81.2%, bending strength of about 51.76 MPa and apparent density of about 1.0 g/cm3.

  4. Synthesis and structures of metal chalcogenide precursors

    Science.gov (United States)

    Hepp, Aloysius F.; Duraj, Stan A.; Eckles, William E.; Andras, Maria T.

    1990-01-01

    The reactivity of early transition metal sandwich complexes with sulfur-rich molecules such as dithiocarboxylic acids was studied. Researchers recently initiated work on precursors to CuInSe2 and related chalcopyrite semiconductors. Th every high radiation tolerance and the high absorption coefficient of CuInSe2 makes this material extremely attractive for lightweight space solar cells. Their general approach in early transition metal chemistry, the reaction of low-valent metal complexes or metal powders with sulfur and selenium rich compounds, was extended to the synthesis of chalcopyrite precursors. Here, the researchers describe synthesis, structures, and and routes to single molecule precursors to metal chalcogenides.

  5. Atomic Layer Deposition from Dissolved Precursors.

    Science.gov (United States)

    Wu, Yanlin; Döhler, Dirk; Barr, Maïssa; Oks, Elina; Wolf, Marc; Santinacci, Lionel; Bachmann, Julien

    2015-10-14

    We establish a novel thin film deposition technique by transferring the principles of atomic layer deposition (ALD) known with gaseous precursors toward precursors dissolved in a liquid. An established ALD reaction behaves similarly when performed from solutions. "Solution ALD" (sALD) can coat deep pores in a conformal manner. sALD offers novel opportunities by overcoming the need for volatile and thermally robust precursors. We establish a MgO sALD procedure based on the hydrolysis of a Grignard reagent.

  6. Progress in molecular precursors for electronic materials

    Energy Technology Data Exchange (ETDEWEB)

    Buhro, W.E. [Washington Univ., St. Louis, MO (United States)

    1996-09-01

    Molecular-precursor chemistry provides an essential underpinning to all electronic-materials technologies, including photovoltaics and related areas of direct interest to the DOE. Materials synthesis and processing is a rapidly developing field in which advances in molecular precursors are playing a major role. This article surveys selected recent research examples that define the exciting current directions in molecular-precursor science. These directions include growth of increasingly complex structures and stoichiometries, surface-selective growth, kinetic growth of metastable materials, growth of size-controlled quantum dots and quantum-dot arrays, and growth at progressively lower temperatures. Continued progress in molecular-precursor chemistry will afford precise control over the crystal structures, nanostructures, and microstructures of electronic materials.

  7. Satellite Observations of Ionospheric Earthquake Precursors

    Science.gov (United States)

    Grimal'Skij, V. V.; Ivchenko, V. N.; Lizunov, G. V.

    The authors review satellite observations of seismogenic phenomena in the ionosphere. Based on literature data, hypothetical patterns of seismogenic phenomena were reconstructed. The authors discuss the reasons which allow the ionospheric "anomalies" to be correlated with eartquake precursors.

  8. Rational design of precursors for oxide ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Apblett, A.W.; Georgieva, G. [Tulane Univ., New Orleans, LA (United States)

    1993-12-31

    The use of molecular species as precursors for inorganic materials has received considerable attention in recent years. As a result, metal-organic precursors are becoming increasingly sophisticated as particular decomposition mechanisms and specific stoichiometry are integrated into their design. The authors have pursued both of these design aspects for the development of low-temperature precursors for mono- and bi-metallic oxide materials. Thus, a great variety of metal complexes with 2- and 3-oximinocarboxylic acids, acyloin oximes, 2,4-diols, and diacetone alcohol have been prepared and their thermal behavior investigated. The results of this investigation and their application to the preparation of a variety of metal, oxide ceramics, will be discussed. Particular attention will be paid to precursors for alumina, titania, zirconia, perovskite-phase ferroelectric materials, and ferrites.

  9. Precursor Parameter Identification for IGBT Prognostics

    Data.gov (United States)

    National Aeronautics and Space Administration — Precursor parameters have been identified to enable development of a prognostic approach for insulated gate bipolar transistors (IGBT). The IGBT were subjected to...

  10. Precursores do discurso visual na imprensa caricata Rio-Grandina = Precursors of visual discourse in the press of satirical cartoons of Rio Grande-RS

    Directory of Open Access Journals (Sweden)

    Sandri, Tammie Caruse Faria

    2014-01-01

    Full Text Available Este estudo discute o papel dos autores na introdução de desenhos em jornais, no final do século XIX, quando as publicações impressas se proliferaram no Rio Grande do Sul. Destaco os pioneiros do traço nas manifestações caricaturais publicadas em Rio Grande – RS, tomando como objeto os jornais caricatos O Amolador, O Diabrete, Marui e Bisturi. O intuito é contribuir para a história da mídia visual, dando visibilidade aos precursores das charges, cartuns, caricaturas pessoais, desenhos de humor e histórias em quadrinhos na imprensa rio-grandina. São analisados os nomes dos integrantes das equipes e as assinaturas encontradas nas edições, estabelecendo relações pertinentes

  11. Sobre a psicopatologia dos atos

    Directory of Open Access Journals (Sweden)

    Roberto Calazans

    2015-07-01

    Full Text Available Este artigo pretende apresentar a psicopatologia dos atos a partir do esquema de Jacques Lacan sobre a angústia. Diferenciamos os acting-out, a passagem ao ato, os sintomas, as inibições e a angústia fazendo uma duplicação do esquema de Lacan levando em consideração os registros do simbólico, do real e do imaginário. Esse esquema permite uma abordagem da questão dos atos do sujeito sem cair em uma perplexidade do clínico, nem na confusão entre os atos e a ação. Permite também uma melhor orientação do clínico em relação às diversas modalidades de respostas subjetivas que não se restringem à questão sintomática, que é o campo inaugural da clínica psicanalítica desde a sua fundação por Sigmund Freud. Acreditamos contribuir, assim, para um maior esclarecimento desse esquema no ensino de Lacan e para que ele possa servir de orientação para o tratamento dos atos do sujeito na clínica.

  12. On the discovery of precursor processing.

    Science.gov (United States)

    Steiner, Donald F

    2011-01-01

    Studies of the biosynthesis of insulin in a human insulinoma beginning in 1965 provided the first evidence for a precursor of insulin, the first such prohormone to be identified. Further studies with isolated rat islets then confirmed that the precursor became labeled more rapidly than insulin and later was converted to insulin by a proteolytic processing system located mainly within the secretory granules of the beta cell and was then stored or secreted. The precursor was designated "proinsulin" in 1967 and was isolated and sequenced from beef and pork sources. These structural studies confirmed that the precursor was a single polypeptide chain which began with the B chain of insulin, continued through a connecting segment of 30-35 amino acids and terminated with the A chain. Paired basic residues were identified at the sites of excision of the C-peptide. Human proinsulin and C-peptide were then similarly obtained and sequenced. The human C-peptide assay was developed and provided a useful tool for measuring insulin levels indirectly in diabetics treated with insulin. The discovery of other precursor proteins for a variety of peptide hormones, neuropeptides, or plasma proteins then followed, with all having mainly dibasic cleavage sites for processing. The subsequent discovery of a similar biosynthetic pathway in yeast led to the identification of eukaryotic families of specialized processing subtilisin-like endopeptidases coupled with carboxypeptidase B-like exopeptidases. Most neuroendocrine peptides are processed by two specialized members of this family - PC2 and/or PC1/3 - followed by carboxypeptidase E (CPE). This brief report concentrates mainly on the role of insulin biosynthesis in providing a useful early paradigm of precursor processing in the secretory pathway.

  13. Carbon fibers: precursor systems, processing, structure, and properties.

    Science.gov (United States)

    Frank, Erik; Steudle, Lisa M; Ingildeev, Denis; Spörl, Johanna M; Buchmeiser, Michael R

    2014-05-19

    This Review gives an overview of precursor systems, their processing, and the final precursor-dependent structure of carbon fibers (CFs) including new developments in precursor systems for low-cost CFs. The following CF precursor systems are discussed: poly(acrylonitrile)-based copolymers, pitch, cellulose, lignin, poly(ethylene), and new synthetic polymeric precursors for high-end CFs. In addition, structure-property relationships and the different models for describing both the structure and morphology of CFs will be presented.

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

    Directory of Open Access Journals (Sweden)

    MARISOL AMAYA-MÁRQUEZ

    2015-01-01

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

  15. Sol-gel precursors and products thereof

    Science.gov (United States)

    Warren, Scott C.; DiSalvo, Jr., Francis J.; Weisner, Ulrich B.

    2017-02-14

    The present invention provides a generalizable single-source sol-gel precursor capable of introducing a wide range of functionalities to metal oxides such as silica. The sol-gel precursor facilitates a one-molecule, one-step approach to the synthesis of metal-silica hybrids with combinations of biological, catalytic, magnetic, and optical functionalities. The single-source precursor also provides a flexible route for simultaneously incorporating functional species of many different types. The ligands employed for functionalizing the metal oxides are derived from a library of amino acids, hydroxy acids, or peptides and a silicon alkoxide, allowing many biological functionalities to be built into silica hybrids. The ligands can coordinate with a wide range of metals via a carboxylic acid, thereby allowing direct incorporation of inorganic functionalities from across the periodic table. Using the single-source precursor a wide range of functionalized nanostructures such as monolith structures, mesostructures, multiple metal gradient mesostructures and Stober-type nanoparticles can be synthesized. ##STR00001##

  16. Sol-gel precursors and products thereof

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Scott C.; DiSalvo, Jr., Francis J.; Weisner, Ulrich B.

    2017-02-14

    The present invention provides a generalizable single-source sol-gel precursor capable of introducing a wide range of functionalities to metal oxides such as silica. The sol-gel precursor facilitates a one-molecule, one-step approach to the synthesis of metal-silica hybrids with combinations of biological, catalytic, magnetic, and optical functionalities. The single-source precursor also provides a flexible route for simultaneously incorporating functional species of many different types. The ligands employed for functionalizing the metal oxides are derived from a library of amino acids, hydroxy acids, or peptides and a silicon alkoxide, allowing many biological functionalities to be built into silica hybrids. The ligands can coordinate with a wide range of metals via a carboxylic acid, thereby allowing direct incorporation of inorganic functionalities from across the periodic table. Using the single-source precursor a wide range of functionalized nanostructures such as monolith structures, mesostructures, multiple metal gradient mesostructures and Stober-type nanoparticles can be synthesized. ##STR00001##

  17. Milk proteins as precursors of bioactive peptides

    Directory of Open Access Journals (Sweden)

    Marta Dziuba

    2009-03-01

    Full Text Available Milk proteins, a source of bioactive peptides, are the subject of numerous research studies aiming to, among others, evaluate their properties as precursors of biologically active peptides. Physiologically active peptides released from their precursors may interact with selected receptors and affect the overall condition and health of humans. By relying on the BIOPEP database of proteins and bioactive peptides, developed by the Department of Food Biochemistry at the University of Warmia and Mazury in Olsztyn (www.uwm.edu.pl/biochemia, the profiles of potential activity of milk proteins were determined and the function of those proteins as bioactive peptide precursors was evaluated based on a quantitative criterion, i.e. the occurrence frequency of bioactive fragments (A. The study revealed that milk proteins are mainly a source of peptides with the following types of activity: antihypertensive (Amax = 0.225, immunomodulating (0.024, smooth muscle contracting (0.011, antioxidative (0.029, dipeptidyl peptidase IV inhibitors (0.148, opioid (0.073, opioid antagonistic (0.053, bonding and transporting metals and metal ions (0.024, antibacterial and antiviral (0.024, and antithrombotic (0.029. The enzymes capable of releasing bioactive peptides from precursor proteins were determined for every type of activity. The results of the experiment indicate that milk proteins such as lactoferrin, α-lactalbumin, β-casein and κ-casein hydrolysed by trypsin can be a relatively abundant source of biologically active peptides.

  18. Sedimentary porphyrins: Correlations with biological precursors

    Energy Technology Data Exchange (ETDEWEB)

    Callot, H.J.; Ocampo, R.; Albrecht, P. (Universite Louis Pasteur, Strasbourg (France))

    Over the past 6 years several sedimentary porphyrins (petroporphyrins, geoporphyrins) were correlated for the first time with biological precursors specific for classes of organisms (algae, photosynthetic bacteria (Chlorobiaceae)). This article discusses the various examples of correlations and the methods that led to these conclusions (isolation of pure porphyrins, structure determination using spectroscopic techniques, total synthesis, isotope measurements).

  19. School Violence: Prevalence, Precursors, and Prevention.

    Science.gov (United States)

    Juvonen, Jaanna

    2002-01-01

    Reviews types of school violence students confront, including a frequent precursor thereto: bullying. Discusses positive and negative aspects of current approach to school violence prevention such as surveillance, zero-tolerance policies, anti-bullying programs. Describes components of model school violence-prevention program. (Contains 38…

  20. Janus microgels produced from functional precursor polymers.

    Science.gov (United States)

    Seiffert, Sebastian; Romanowsky, Mark B; Weitz, David A

    2010-09-21

    Micrometer-sized Janus particles of many kinds can be formed using droplet microfluidics, but in existing methods, the microfluidic templating is strongly coupled to the material synthesis, since droplet solidification occurs through rapid polymerization right after droplet formation. This circumstance limits independent control of the material properties and the morphology of the resultant particles. In this paper, we demonstrate a microfluidic technique to produce functional Janus microgels from prefabricated, cross-linkable precursor polymers. This approach separates the polymer synthesis from the particle gelation, thus allowing the microfluidic droplet templating and the functionalization of the matrix polymer to be performed and controlled in two independent steps. We use microfluidic devices to emulsify semidilute solutions of cross-linkable, chemically modified or unmodified poly(N-isopropylacrylamide) precursors and solidify the drops via polymer-analogous gelation. The resultant microgel particles exhibit two distinguishable halves which contain most of the modified precursors, and the unmodified matrix polymer separates these materials. The spatial distribution of the modified precursors across the particles can be controlled by the flow rates during the microfluidic experiments. We also form hollow microcapsules with two different sides (Janus shells) using double emulsion droplets as templates, and we produce Janus microgels that are loaded with a ferromagnetic additive which allows remote actuation of the microgels.

  1. Detection of Chemical Precursors of Explosives

    Science.gov (United States)

    Li, Jing

    2012-01-01

    Certain selected chemicals associated with terrorist activities are too unstable to be prepared in final form. These chemicals are often prepared as precursor components, to be combined at a time immediately preceding the detonation. One example is a liquid explosive, which usually requires an oxidizer, an energy source, and a chemical or physical mechanism to combine the other components. Detection of the oxidizer (e.g. H2O2) or the energy source (e.g., nitromethane) is often possible, but must be performed in a short time interval (e.g., 5 15 seconds) and in an environment with a very small concentration (e.g.,1 100 ppm), because the target chemical(s) is carried in a sealed container. These needs are met by this invention, which provides a system and associated method for detecting one or more chemical precursors (components) of a multi-component explosive compound. Different carbon nanotubes (CNTs) are loaded (by doping, impregnation, coating, or other functionalization process) for detecting of different chemical substances that are the chemical precursors, respectively, if these precursors are present in a gas to which the CNTs are exposed. After exposure to the gas, a measured electrical parameter (e.g. voltage or current that correlate to impedance, conductivity, capacitance, inductance, etc.) changes with time and concentration in a predictable manner if a selected chemical precursor is present, and will approach an asymptotic value promptly after exposure to the precursor. The measured voltage or current are compared with one or more sequences of their reference values for one or more known target precursor molecules, and a most probable concentration value is estimated for each one, two, or more target molecules. An error value is computed, based on differences of voltage or current for the measured and reference values, using the most probable concentration values. Where the error value is less than a threshold, the system concludes that the target

  2. Remessas de recursos dos imigrantes

    Directory of Open Access Journals (Sweden)

    Ana Cristina Braga Martes

    2006-08-01

    Full Text Available AS REMESSAS contribuem para o desenvolvimento local e para redução da pobreza? Essa é a pergunta-chave que os estudos recentes sobre migrações internacionais têm levantado. O que se está procurando compreender é de que modo as remessas poderiam afetar positiva ou negativamente a economia dos países de origem dos imigrantes. Discutir o papel e o significado das remessas implica, assim, uma discussão em torno da existência (ou não de um "campo de positividades" do fenômeno migratório internacional. O principal objetivo deste artigo é contribuir para essa discussão por meio de um estudo empírico do caso brasileiro que adota as remessas como foco. Para tanto, é identificado o perfil das remessas e dos remetentes, assim como os objetivos e os beneficiários do dinheiro enviado. A pesquisa usa uma abordagem baseada em entrevistas em profundidade e survey não-representativo (Boston e Governador Valadares.DO REMITTANCES contribute to local development and the reduction of poverty? What are the consequences of the dollars sent by the migrants to the people, families, and organizations that receive them in the cities of origin? These are the key questions that recent studies have raised. According to some authors "migration is inevitable and has the potential to be quite positive in terms of development and reduction of poverty. The policies that have their origins in this principle will be more successful than those that attempt to oppose, intransigently, both globalization and the migration of people in space". Do current international migrations produce positive local development effects? The main objective of this article is to contribute to this discussion through an empirical study of the Brazilian case, which takes remittances as its focus. Thus, we identify who the immigrants are who send remittances from the United States to Brazil, to what ends the remittances are directed, who the beneficiaries are, and how the remittances

  3. Teogonia - O Nascimento dos Deuses

    OpenAIRE

    Tórma, Alan David dos Santos

    2014-01-01

    O texto grego utilizado foi o da edição inglesa de Hugh G. Evelyn-White (HESIOD, 1914). Foram consultadas a título de comparação as traduções da Teogonia de Ana Lúcia Silveira Cerqueira e Maria Therezinha Áreas Lyra (HESÍODO, 1986), José Antonio Alves Torrano (HESÍODO, 1995), Hugh G. Evelyn-White (HESIOD, 1914) e José Marcos Mariani de Macedo (MACEDO, 2010). Além disso, esta tradução se baseou pelas traduções dos Hinos Homéricos, Edvanda Bonavina da Rosa et alia (2010), e da Odisseia, de Traj...

  4. Las dos triadas de Bejarano

    Directory of Open Access Journals (Sweden)

    González Jorge Iván

    2002-08-01

    Full Text Available El artículo diseute "dos tríadas" que propone Bejarano para calificar a la teoría económica actual. La primera tríada tiene que ver con el realismo, la pertinencia y la relevancia de la teoría. Y la segunda tríada con sus dimensiones política, institucional y moral. El artículo centra la atención en esta segunda tríada, argumentando que la teoría no es apolítica, ainstitucional y amoral como afirma Bejarano. El examen crítico de la posición de Bejarano se sustenta en algunas de las tesis de: Walras, Marshall, Hicks, vickrey, Samuelson y Arrow.

  5. O surgimento dos direitos republicanos

    Directory of Open Access Journals (Sweden)

    Amanda Cristina Carvalho Canezin

    2015-09-01

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

  6. Tratamento dos datos analíticos

    OpenAIRE

    Yebra Biurrun, María del Carmen

    2008-01-01

    Esta unidade didáctica é a primeira toma de contacto do alumnado co estudo do tratamento dos datos analíticos e a comprobación da súa calidade. Este estudo poderase completar máis adiante dentro do programa desta materia cando se presente o resto dos parámetros de calidade dos métodos analíticos. A importancia deste tema radica en que unha vez obtidos os datos analíticos, o primeiro aspecto que se ten que considerar é a verificación da calidade dos mesmos en termos de exactitude e precisió...

  7. [Presentation of the Lunar Precursor Robotics Program

    Science.gov (United States)

    Lavoie, Anthony R.

    2008-01-01

    The Lunar Precursor Robotics Program (LPRP) is the host program for the Exploration Systems Mission Directorate's (ESMD) lunar robotic precursor missions to the Moon. The program includes two missions, the Lunar Reconnaissance Orbiter (LRO), and the Lunar CRater Observation and Sensing Satellite (LCROSS). Both missions will provide the required lunar information to support development and operations of those systems required for Human lunar return. LPRP is developing a lunar mapping plan, Called the Lunar Mapping and Modeling Project, to create the capability to archive and present all data from LRO, LCROSS, historical lunar missions, and international lunar missions for future mission planning and operations. LPRP is also developing its educational and public outreach activities for the Vision for Space Exploration's first missions. LPRP is working closely with the Science Mission Directorate as their lunar activities come into focus.

  8. Nonlinear magnetohydrodynamics of edge localized mode precursors

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Z. B., E-mail: guozhipku@gmail.com [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing (China); WCI Center for Fusion Theory, NFRI, Gwahangno 113, Yusung-gu, Daejeon 305-333 (Korea, Republic of); Wang, Lu [SEEE, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Wang, X. G. [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing (China)

    2015-02-15

    A possible origin of edge-localized-mode (ELM) precursors based on nonlinear ideal peeling-ballooning mode is reported. Via nonlinear variational principle, a nonlinear evolution equation of the radial displacement is derived and solved, analytically. Besides an explosive growth in the initial nonlinear phase, it is found that the local displacement evolves into an oscillating state in the developed nonlinear phase. The nonlinear frequency of the ELM precursors scales as ω{sub pre}∼x{sup 1/3}ξ{sup ^}{sub ψ,in}{sup 2/3}n, with x position in radial direction, ξ{sup ^}{sub ψ,in} strength of initial perturbation, and n toroidal mode number.

  9. Functional Nanoporous Polymers from Block Copolymer Precursors

    DEFF Research Database (Denmark)

    Guo, Fengxiao

    functionalities remains a great challenge due to the limitation of available polymer synthesis and the nanoscale confinement of the porous cavities. The main topic of this thesis is to develop methods for fabrication of functional nanoporous polymers from block copolymer precursors. A method has been developed...... functional nanoporous polymers based on nanoporous 1,2- polybuatdiene 1,2-PB, which is derived from a 1,2-PB-b-PDMS diblock copolymer precursor. As a result, nanoporous 1,2-PB with pores decorated of polyacrylates, sulfonated polymers and poly(ethylene glycol) are created. A method of vapor phase deposition...... has also been generated to obtain nanoporous polymers with functional coatings on pore walls. Vapor phase polymerization of pyrrole is performed to incorporate an ultra thin film of polypyrrole into nanoporous 1,2-PB. The preliminary test shows that nanoporous 1,2-PB gains conductivity. Generally...

  10. Electromagnetic Whistler Precursors at Supercritical Interplanetary Shocks

    Science.gov (United States)

    Wilson, L. B., III

    2012-01-01

    We present observations of electromagnetic precursor waves, identified as whistler mode waves, at supercritical interplanetary shocks using the Wind search coil magnetometer. The precursors propagate obliquely with respect to the local magnetic field, shock normal vector, solar wind velocity, and they are not phase standing structures. All are right-hand polarized with respect to the magnetic field (spacecraft frame), and all but one are right-hand polarized with respect to the shock normal vector in the normal incidence frame. Particle distributions show signatures of specularly reflected gyrating ions, which may be a source of free energy for the observed modes. In one event, we simultaneously observe perpendicular ion heating and parallel electron acceleration, consistent with wave heating/acceleration due to these waves.

  11. Calculations of precursor propagation in dispersive dielectrics.

    Energy Technology Data Exchange (ETDEWEB)

    Bacon, Larry Donald

    2003-08-01

    The present study is a numerical investigation of the propagation of electromagnetic transients in dispersive media. It considers propagation in water using Debye and composite Rocard-Powles-Lorentz models for the complex permittivity. The study addresses this question: For practical transmitted spectra, does precursor propagation provide any features that can be used to advantage over conventional signal propagation in models of dispersive media of interest? A companion experimental study is currently in progress that will attempt to measure the effects studied here.

  12. PRECURSORS OF EARTHQUAKES: VLF SIGNALSIONOSPHERE IONOSPHERE RELATION

    Directory of Open Access Journals (Sweden)

    Mustafa ULAS

    2013-01-01

    Full Text Available lot of people have died because of earthquakes every year. Therefore It is crucial to predict the time of the earthquakes reasonable time before it had happed. This paper presents recent information published in the literature about precursors of earthquakes. The relationships between earthquakes and ionosphere are targeted to guide new researches in order to study further to find novel prediction methods.

  13. Cellular Kinetics of Perivascular MSC Precursors

    Directory of Open Access Journals (Sweden)

    William C. W. Chen

    2013-01-01

    Full Text Available Mesenchymal stem/stromal cells (MSCs and MSC-like multipotent stem/progenitor cells have been widely investigated for regenerative medicine and deemed promising in clinical applications. In order to further improve MSC-based stem cell therapeutics, it is important to understand the cellular kinetics and functional roles of MSCs in the dynamic regenerative processes. However, due to the heterogeneous nature of typical MSC cultures, their native identity and anatomical localization in the body have remained unclear, making it difficult to decipher the existence of distinct cell subsets within the MSC entity. Recent studies have shown that several blood-vessel-derived precursor cell populations, purified by flow cytometry from multiple human organs, give rise to bona fide MSCs, suggesting that the vasculature serves as a systemic reservoir of MSC-like stem/progenitor cells. Using individually purified MSC-like precursor cell subsets, we and other researchers have been able to investigate the differential phenotypes and regenerative capacities of these contributing cellular constituents in the MSC pool. In this review, we will discuss the identification and characterization of perivascular MSC precursors, including pericytes and adventitial cells, and focus on their cellular kinetics: cell adhesion, migration, engraftment, homing, and intercellular cross-talk during tissue repair and regeneration.

  14. Precursor lesions of invasive breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Schreer, Ingrid [Breast Center, University Hospital Kiel, Kiel (Germany)]. E-mail: ischreer@email.uni-kiel.de; Luettges, Jutta [Department of Pathology, University Hospital Kiel, Kiel (Germany)

    2005-04-01

    The increasing application of mammography, mainly in screening programs for the early detection of breast cancer, and the high technical standard of imaging has resulted in the detection of clinically occult breast tumors. Considering that only diagnosis at an early stage will be able to change the prognosis of breast cancer, this diagnostic challenge appears to be the most exciting field in both breast imaging and breast pathology. Especially the precursor lesions need to be diagnosed and defined precisely to understand their prognostic significance. In imaging, the morphologic appearance of precursor lesions is usually neither typical nor pathognomonic. They have to be assessed histologically using percutaneous interventions. Recent molecular studies have demonstrated various genetic alterations in the ductal epithelium, with the earliest onset in atypical ductal hyperplasia. The recent WHO classification, which is based on molecular data and histopathological features, attempts to define in particular the precursor lesions and low grade intraductal carcinomas. The clinical importance of the various grades has to be assessed. Intimate cooperation between diagnostic radiologist and pathologist is essential.

  15. Precursor lesions of invasive breast cancer.

    Science.gov (United States)

    Schreer, Ingrid; Lüttges, Jutta

    2005-04-01

    The increasing application of mammography, mainly in screening programs for the early detection of breast cancer, and the high technical standard of imaging has resulted in the detection of clinically occult breast tumors. Considering that only diagnosis at an early stage will be able to change the prognosis of breast cancer, this diagnostic challenge appears to be the most exciting field in both breast imaging and breast pathology. Especially the precursor lesions need to be diagnosed and defined precisely to understand their prognostic significance. In imaging, the morphologic appearance of precursor lesions is usually neither typical nor pathognomonic. They have to be assessed histologically using percutaneous interventions. Recent molecular studies have demonstrated various genetic alterations in the ductal epithelium, with the earliest onset in atypical ductal hyperplasia. The recent WHO classification, which is based on molecular data and histopathological features, attempts to define in particular the precursor lesions and low grade intraductal carcinomas. The clinical importance of the various grades has to be assessed. Intimate cooperation between diagnostic radiologist and pathologist is essential.

  16. Ionospheric precursors for crustal earthquakes in Italy

    Directory of Open Access Journals (Sweden)

    L. Perrone

    2010-04-01

    Full Text Available Crustal earthquakes with magnitude 6.0>M≥5.5 observed in Italy for the period 1979–2009 including the last one at L'Aquila on 6 April 2009 were considered to check if the earlier obtained relationships for ionospheric precursors for strong Japanese earthquakes are valid for the Italian moderate earthquakes. The ionospheric precursors are based on the observed variations of the sporadic E-layer parameters (h'Es, fbEs and foF2 at the ionospheric station Rome. Empirical dependencies for the seismo-ionospheric disturbances relating the earthquake magnitude and the epicenter distance are obtained and they have been shown to be similar to those obtained earlier for Japanese earthquakes. The dependences indicate the process of spreading the disturbance from the epicenter towards periphery during the earthquake preparation process. Large lead times for the precursor occurrence (up to 34 days for M=5.8–5.9 tells about a prolong preparation period. A possibility of using the obtained relationships for the earthquakes prediction is discussed.

  17. Disinfection byproduct formation from lignin precursors.

    Science.gov (United States)

    Hua, Guanghui; Kim, Junsung; Reckhow, David A

    2014-10-15

    Lignin is the most abundant aromatic plant component in terrestrial ecosystems. This study was conducted to determine the contribution of lignin residues in natural water to the formation of disinfection byproducts (DBPs) in drinking water. We investigated the formation of different classes of DBPs from lignin model compounds, lignin polymers, and humic substances using two common disinfection techniques, chlorination and chloramination. The contributions of lignin to the overall formation of DBPs from these organic products were determined based on the observed abundances of individual lignin phenols and their DBP yields. Model lignin phenols generally produced higher trichloroacetic acid (TCAA) yields than chloroform and dichloroacetic acid (DCAA) during chlorination. Lignin phenols generally produced higher DBP yields but lower percentages of unknown total organic halogen compared to bulk humic substances and lignin polymers. The relative significance of lignin phenols as chlorination DBP precursors generally follows the order of TCAA > DCAA&chloroform. The relative significance of lignin phenols to DBP formation by chloramination follows the order: TCAA > DCAA&DCAN > chloroform. Overall, lignin phenols are more important as TCAA precursors than as chloroform and DCAA precursors.

  18. Perfil dos idosos que cochilam

    Directory of Open Access Journals (Sweden)

    Ariene Angelini dos Santos

    2013-12-01

    Full Text Available Esse estudo objetivou caracterizar os idosos que cochilam segundo as características sociodemográficas e de fragilidade. Estudo descritivo, transversal, recorte do projeto multicêntrico Fragilidade em Idosos Brasileiros. Foram avaliados 1.866 idosos utilizando-se questionário sociodemográfico. A fragilidade foi avaliada usando o fenótipo proposto por Fried. Os dados foram tratados com estatística descritiva. Os resultados apontaram que o perfil do idoso que cochila foi constituído predominantemente por mulheres, casadas, aposentadas, pré-frágeis, com média de idade de 73 anos, quatro anos de estudo, renda familiar mensal de 3,9 salários mínimos, com 4,4 filhos e que residiam apenas com eles. Os idosos relataram cochilar em média 5,9 dias por semana, com duração de 53,5 minutos por cochilo. Conhecer o perfil do idoso que cochila contribui para os profissionais de saúde desenvolverem ações em relação aos problemas de sono dos idosos frágeis/pré-frágeis, prevenindo, minimizando ou resolvendo esses problemas.

  19. O Conceito Kantiano de Metafisica dos Costumes

    Directory of Open Access Journals (Sweden)

    Joel Thiago Klein

    2009-06-01

    Full Text Available Neste texto reconstrói-se o conceito kantiano de metafísica dos costumes com o objetivo de apresentar claramente os seus aspectos essenciais, mas sem entrar em questões relativas a sua legitimidade. Nas primeiras duas partes do trabalho mostra-se como Kant reinterpreta a divisão geral da filosofia e como o conceito de uma metafísica dos costumes passa a ser visto a partir do empreendimento crítico-transcendental. Na terceira parte aponta-se para algumas nuances e ambigüidades do conceito de “Metafísica dos costumes”. Por fim, enumera-se os motivos teóricos e práticos a partir dos quais Kant defende a necessidade de uma Metafísica dos costumes.

  20. Os organismos geneticamente modificados e a rotulagem dos alimentos - uma análise a partir dos direitos dos consumidores

    Directory of Open Access Journals (Sweden)

    Marcello Vitor Rocha Cota

    2015-11-01

    Full Text Available Ao longo do presente trabalho serão analisados os organismos geneticamente modificados (OGMs frente aos riscos à saúde alimentar e ao meio ambiente, sobretudo o princípio da precaução e a rotulagem dos produtos. A partir de uma dimensão comparativa de três realidades distintas, isto é, a estadunidense, a europeia, com ênfase mercado ao português, e a brasileira – sob um prisma ambiental, a rotulagem dos produtos será confrontada com os direitos dos consumidores, embora em determinadas ocasiões, diante da inexistência de informações adequadas e claras dos produtos, que estão sendo ofertados e consumidos, os consumidores não sabem o que estão consumindo.

  1. Abordagem contingencial no gerenciamento dos recursos humanos

    OpenAIRE

    Pacheco Junior, Waldemar

    2004-01-01

    Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Engenharia de Produção. O capital humano é tido como um dos fatores estratégicos às organizações, porém, um dos grandes desafios sob o ponto de vista do gerenciamento é o de melhor aproveitar o potencial dos trabalhadores, em face das dificuldades de encontrar formas de congruência entre objetivos de empresa e pessoas nela inseridas. Tal problema é normalmente uma decorrência de dese...

  2. Estrutura temporal dos tipos de xuro

    OpenAIRE

    Reboredo Nogueira, Juan Carlos

    2013-01-01

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

  3. Neutron-powered precursors of kilonovae

    CERN Document Server

    Metzger, Brian D; Goriely, Stephane; Kasen, Daniel

    2014-01-01

    The merger of binary neutron stars (NSs) ejects a small quantity of neutron rich matter, the radioactive decay of which powers a day to week long thermal transient known as a kilonova. Most of the ejecta remains sufficiently dense during its expansion that all neutrons are captured into nuclei during the r-process. However, recent general relativistic merger simulations by Bauswein and collaborators show that a small fraction of the ejected mass (a few per cent, or ~1e-4 Msun) expands sufficiently rapidly for most neutrons to avoid capture. This matter originates from the shocked-heated interface between the merging NSs. Here we show that the beta-decay of these free neutrons in the outermost ejecta powers a `precursor' to the main kilonova emission, which peaks on a timescale of a few hours following merger at U-band magnitude ~22 (for an assumed distance of 200 Mpc). The high luminosity and blue colors of the neutron precursor render it a potentially important counterpart to the gravitational wave source, t...

  4. Precursors of eruptions at Vesuvius (Italy)

    Science.gov (United States)

    Scandone, Roberto; Giacomelli, Lisetta

    2008-04-01

    The historical record of activity of Mount Vesuvius is uncommonly long and may serve as a guide to understand precursors before the outbreak of new activity. Reposes of different lengths have been observed in the past, with long ones preceding violent explosive eruptions. Eruptions occurring during periods of permanent activity have been preceded by possible deformation of the volcanic edifice and by short duration, earthquake swarms. Otherwise they have occurred without any reported precursors. The renewal of activity after long periods, like the current one, has been preceded by unrest lasting years to weeks, as a new eruption would require connection to the surface of a reservoir at depth ranging between 6 and 4 km. Since 1944, episodic seismic swarms, have occurred with a frequency similar to that of the violent strombolian eruptions during the last period of permanent activity; they are interpreted as intrusions and arrest of magma batches into a reservoir at the same depth of that feeding past sub-plinian eruptions.

  5. Precursor Mediated Synthesis of Nanostructured Silicas: From Precursor-Surfactant Ion Pairs to Structured Materials

    Directory of Open Access Journals (Sweden)

    Peter Hesemann

    2014-04-01

    Full Text Available The synthesis of nanostructured anionic-surfactant-templated mesoporous silica (AMS recently appeared as a new strategy for the formation of nanostructured silica based materials. This method is based on the use of anionic surfactants together with a co-structure-directing agent (CSDA, mostly a silylated ammonium precursor. The presence of this CSDA is necessary in order to create ionic interactions between template and silica forming phases and to ensure sufficient affinity between the two phases. This synthetic strategy was for the first time applied in view of the synthesis of surface functionalized silica bearing ammonium groups and was then extended on the formation of materials functionalized with anionic carboxylate and bifunctional amine-carboxylate groups. In the field of silica hybrid materials, the “anionic templating” strategy has recently been applied for the synthesis of silica hybrid materials from cationic precursors. Starting from di- or oligosilylated imidazolium and ammonium precursors, only template directed hydrolysis-polycondensation reactions involving complementary anionic surfactants allowed accessing structured ionosilica hybrid materials. The mechanistic particularity of this approach resides in the formation of precursor-surfactant ion pairs in the hydrolysis-polycondensation mixture. This review gives a systematic overview over the various types of materials accessed from this cooperative ionic templating approach and highlights the high potential of this original strategy for the formation of nanostructured silica based materials which appears as a complementary strategy to conventional soft templating approaches.

  6. Dispositivo de armazenamento de energia utilizando polianilina e eletrolito polimerico

    OpenAIRE

    Silvia Cilene R. Catharino

    2000-01-01

    Resumo: Recentemente, os capacitores eletroquímicos têm merecido muita atenção na área de armazenamento de energia, devido a sua possível aplicação em veículos elétricos e aparelhos eletrônicos. O desenvolvimento nessa área requer um armazenamento de energia com alta densidade e tempos curtos de carga e descarga. Polímeros condutores tem a vantagem sobre óxidos, como eletrodos para capacitores, porque são fáceis de processar e tem baixo custo de produção. Neste trabalho são mostrados resultad...

  7. Antifreeze polymeric additives for fuels; Aditivos polimericos anticongelantes para combustiveis

    Energy Technology Data Exchange (ETDEWEB)

    Muniz, Aline S.; Carvalho, Agne Roani de; Sakae, George Hideki; Oliveira, Angelo R.S.; Cesar-Oliveira, Maria Aparecida F. [Universidade Federal do Parana - UFPR - Departamento de Quimica - LABPOL-Laboratorio de Polimeros Sinteticos, Centro Politecnico, Curitiba, PR (Brazil)], e-mails: mafco@ufpr.br, alinemuniz@ufpr.br

    2011-07-01

    Owing to the current interest in the reduction of environmental pollution, several researchers are seeking renewable sources of energy which can at least partially replace combustibles derived from petroleum. Diesel oil is the combustible that most seriously pollutes the environment and is thus the biodiesel that is being considered as a fuel which can be replaced by a renewable combustible; this can possibly be used in diesel engines without any modifications. However, certain problems have to be overcome with regard to the temperature at which the biodiesel should be stored and used, since there is a tendency for biodiesel to solidify at low temperatures. This suggests that there is a need for the use of anti-freeze additives. This work behind the main focus additives with only 25 ppm, were able to reduce the pour point of fuel, achieving significant results, for example, the additive M14A18 lowered the pour point (PP) of B20 to -20 degree C, showing that the use of increasing amounts of biodiesel to diesel can aggregate. The main focus of work behind the development of additives that with only 25 ppm, were able to reduce the pour point of fuel, producing significant results such as those obtained with the use of additive M14A18 which lowered the pour point of the B20 to -20 degree C, showing the possibility of using increasing amounts of biodiesel added to diesel. (author)

  8. Estudo dos ruidos articulares atraves da tecnica artrosonografica dos joelhos normais de individuos jovens

    OpenAIRE

    Roberto Natalino Ricarte

    1987-01-01

    Resumo: Os ruídos articulares do joelho esquerdo normal de 43 indivíduos jovens de ambos os sexos, sendo 20 do sexo masculino e 23 do sexo feminino, foram analisados através da técnica artrosonográfica. As gravações destes ruídos obtidas em uma sala acústica, onde buscamos diminuir e foram evitar os possiveis ruidos extrinsecos as gravaçoes. Estes ruidos foram transportados posteriormente para um gravador de rolo acoplado a um eletromiógrafo, de onde obtivemos a análise dos ruídos articulares...

  9. Ancient engineers' inventions precursors of the present

    CERN Document Server

    Rossi, Cesare

    2017-01-01

    This book describes the inventions and designs of ancient engineers who are the precursors of the present. The period ranges mainly from 300 B.C. to 1600 A.D. with several exceptions. Many of the oldest inventions are documented by archaeological finds, often very little known, mainly from Pompeii, Herculaneum and Stabiae and reveal a surprising modernity in their conception. Most of the inventions presented in the first four parts of the book were conceived up to the late Roman Empire and may be considered as milestones, each in their respective field. The fifth part concentrates on more recent centuries. The sixth part deals with some building construction techniques. Generally, for each of the presented inventions, three elements of research and reference are provided: written documents (the classics), iconic references (coins, bas-reliefs, etc.) and archaeological findings. The authors did not write this book for engineers only; hence they describe all the devices without assuming wide technical knowledge...

  10. Mars MetNet Precursor Mission Status

    Science.gov (United States)

    Harri, A.-M.; Aleksashkin, S.; Guerrero, H.; Schmidt, W.; Genzer, M.; Vazquez, L.; Haukka, H.

    2013-09-01

    We are developing a new kind of planetary exploration mission for Mars in collaboration between the Finnish Meteorological Institute (FMI), Lavochkin Association (LA), Space Research Institute (IKI) and Institutio Nacional de Tecnica Aerospacial (INTA). The Mars MetNet mission is based on a new semi-hard landing vehicle called MetNet Lander (MNL). The scientific payload of the Mars MetNet Precursor [1] mission is divided into three categories: Atmospheric instruments, Optical devices and Composition and structure devices. Each of the payload instruments will provide significant insights in to the Martian atmospheric behavior. The key technologies of the MetNet Lander have been qualified and the electrical qualification model (EQM) of the payload bay has been built and successfully tested.

  11. Naphthalene and its precursors in Iomex

    Energy Technology Data Exchange (ETDEWEB)

    Bhagat, S.D.; Sharma, B.K. [Indian Institute of Petroleum, Dehradun (India)

    1995-05-01

    Iomex, an aromatic rich concentrate from kerosene feedstock is a potential source for production of naphthalene which has a variety of industrial applications. Four analytical procedures were standardized for compositional study of iomex according to chemical class. Hydrocarbon group type separation (saturates, mono- and diaromatics) and quantitation was reported using column chromatography, gas chromatography, high performance liquid chromatography and mass spectrometry. Data generated by these techniques are in good agreement with each other. A diaromatic fraction containing naphthalene and its precursors was studied in detail by gas chromatography mass spectrometry (GC-MS). Capillary GC could resolve each and every component of the diaromatic fraction, whereas quantitation and characterization of 27 components were obtained by mass spectrometry. 10 refs., 3 figs., 2 tabs.

  12. The intramolecular click reaction using 'carbocontiguous' precursors.

    Science.gov (United States)

    Patil, Pravin C; Luzzio, Frederick A

    2017-07-20

    The synthesis and utilization of all carbon-chain 'carbocontiguous' azidoalkynyl precursors for an intramolecular click reaction is described. The substrates contain both azidoalkyl and ethynylmethyl groups which are conjoined by a 2-(phenylsulfonylmethyl)-4,5-diphenyloxazole lynchpin and are suitably disposed for ring closure. On promotion by copper salts, a number of cyclic click products having the 1,4-disubstituted endo-fused triazole component and the 4,5-diphenyloxazole component are obtained. In one case, removal of the phenylsulfonylmethyl group from the substrate prior to cyclization gave the 1,5-disubstituted exo-fused triazole. The utilization of CuSO4/sodium ascorbate system appears to be the optimal conditions for closure/cyclization and afforded the cyclized products in yields of 84-95%.

  13. Nanomechanics controls neuronal precursors adhesion and differentiation.

    Science.gov (United States)

    Migliorini, Elisa; Ban, Jelena; Grenci, Gianluca; Andolfi, Laura; Pozzato, Alessandro; Tormen, Massimo; Torre, Vincent; Lazzarino, Marco

    2013-08-01

    The ability to control the differentiation of stem cells into specific neuronal types has a tremendous potential for the treatment of neurodegenerative diseases. In vitro neuronal differentiation can be guided by the interplay of biochemical and biophysical cues. Different strategies to increase the differentiation yield have been proposed, focusing everything on substrate topography, or, alternatively on substrate stiffness. Both strategies demonstrated an improvement of the cellular response. However it was often impossible to separate the topographical and the mechanical contributions. Here we investigate the role of the mechanical properties of nanostructured substrates, aiming at understanding the ultimate parameters which govern the stem cell differentiation. To this purpose a set of different substrates with controlled stiffness and with or without nanopatterning are used for stem cell differentiation. Our results show that the neuronal differentiation yield depends mainly on the substrate mechanical properties while the geometry plays a minor role. In particular nanostructured and flat polydimethylsiloxane (PDMS) substrates with comparable stiffness show the same neuronal yield. The improvement in the differentiation yield obtained through surface nanopatterning in the submicrometer scale could be explained as a consequence of a substrate softening effect. Finally we investigate by single cell force spectroscopy the neuronal precursor adhesion on the substrate immediately after seeding, as a possible critical step governing the neuronal differentiation efficiency. We observed that neuronal precursor adhesion depends on substrate stiffness but not on surface structure, and in particular it is higher on softer substrates. Our results suggest that cell-substrate adhesion forces and mechanical response are the key parameters to be considered for substrate design in neuronal regenerative medicine.

  14. The crustal micro-deformation anomaly and the credible precursor*

    Institute of Scientific and Technical Information of China (English)

    张雁滨; 蒋骏; 钱家栋; 陈京; 和升棋; 张燕; 和平

    2002-01-01

    @@ What is a credible seismic precursor in observation of deformation A real seismic precursor ought to be resulted from the variations in the earth strain and stress. The deformation observation can provide the information during earthquake gestation and occurrence period for us. Usually the seismic precursors can be divided into field and epicentral region precursors. The precursor information is very useful for seismic prediction from epicentral region or near epicentral region. Micro-deformation observation mainly includes tilt, strain and gravity observation. Compared with GPS, geodesy and mobile deformation observation, micro-deformation (tilt, strain) shows the change of deformation which is continual in a limited volume with dominant observed range of 10(6~10(10 m. Because the variation of the crustal nature and cracking can be directly obtained by micro-deformation observation, it is an effective way to find middle-short term and short-term precursor.

  15. Preparation and Characterization of TaN ALD Precursors

    Institute of Scientific and Technical Information of China (English)

    Delong Zhang; Tracy Yund; Cynthia A.Hoover

    2004-01-01

    High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET > PDMAT > TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.

  16. Lessons learned on probabilistic methodology for precursor analyses

    Energy Technology Data Exchange (ETDEWEB)

    Babst, Siegfried [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) gGmbH, Berlin (Germany); Wielenberg, Andreas; Gaenssmantel, Gerhard [Gesellschaft fuer Anlagen- und Reaktorsicherheit (GRS) gGmbH, Garching (Germany)

    2016-11-15

    Based on its experience in precursor assessment of operating experience from German NPP and related international activities in the field, GRS has identified areas for enhancing probabilistic methodology. These are related to improving the completeness of PSA models, to insufficiencies in probabilistic assessment approaches, and to enhancements of precursor assessment methods. Three examples from the recent practice in precursor assessments illustrating relevant methodological insights are provided and discussed in more detail. Our experience reinforces the importance of having full scope, current PSA models up to Level 2 PSA and including hazard scenarios for precursor analysis. Our lessons learned include that PSA models should be regularly updated regarding CCF data and inclusion of newly discovered CCF mechanisms or groups. Moreover, precursor classification schemes should be extended to degradations and unavailabilities of the containment function. Finally, PSA and precursor assessments should put more emphasis on the consideration of passive provisions for safety, e. g. by sensitivity cases.

  17. BENEFÍCIOS DOS PARQUES URBANOS

    Directory of Open Access Journals (Sweden)

    Raphael Tavares Pacheco Martins

    2014-07-01

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

  18. DSC Study on the Polyacrylonitrile Precursors for Carbon Fibers

    Institute of Scientific and Technical Information of China (English)

    Wangxi ZHANG; Musen LI

    2005-01-01

    Different polyacrylonitrile (PAN) precursor fibers that displayed various thermal properties were studied by using differential scanning calorimetry (DSC). Results showed that some commercial PAN precursor fibers displayed double separated peaks and these fibers were of high quality because of their process stability during their conversion to carbon fibers of high performance. Some fabrication processes, such as spinning, drawing, could not apparently change the DSC features of a PAN precursor fiber. It was concluded that the thermal properties of a PAN precursor fiber was mainly determined from its comonomer content type and compositions.

  19. Development of an accident sequence precursor methodology and its application to significant accident precursors

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Seung Hyun; Park, Sung Hyun; Jae, Moo Sung [Dept. of of Nuclear Engineering, Hanyang University, Seoul (Korea, Republic of)

    2017-03-15

    The systematic management of plant risk is crucial for enhancing the safety of nuclear power plants and for designing new nuclear power plants. Accident sequence precursor (ASP) analysis may be able to provide risk significance of operational experience by using probabilistic risk assessment to evaluate an operational event quantitatively in terms of its impact on core damage. In this study, an ASP methodology for two operation mode, full power and low power/shutdown operation, has been developed and applied to significant accident precursors that may occur during the operation of nuclear power plants. Two operational events, loss of feedwater and steam generator tube rupture, are identified as ASPs. Therefore, the ASP methodology developed in this study may contribute to identifying plant risk significance as well as to enhancing the safety of nuclear power plants by applying this methodology systematically.

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

    Directory of Open Access Journals (Sweden)

    Deonir de Toni

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

  1. Esbozo para una biografía del precursor Pedro Fermín Vargas

    Directory of Open Access Journals (Sweden)

    Guillermo Hernández de Alba

    1979-04-01

    Full Text Available Dos siglos corridos desde su nacimiento, más de uno y medio de la proclamación de la Independencia Nacional, han sido necesarios para que la memoria de Pedro Fermín de Vargas sea públicamente restituida a su patria, que al conocer y estudiar su vida extraordinaria lo celebrará entre los precursores de su libertad, lo admirará por la excelencia de su clara inteligencia y de su formación intelectual y le dará sitio de honor en los anales de su historia económica porque es capaz de proyectar, con arte de visionario, el estudio perfecto de la producción nacional y la distribución de su riqueza latente.

  2. Eruption precursors: Manifestations and strategies for detection

    Science.gov (United States)

    Poland, Michael; Pritchard, Matthew

    2017-04-01

    The past several decades have seen a rapid increase in volcano monitoring and modeling capabilities. Diverse arrays of instrument networks can detect a variety of pre-, co-, and post-eruptive phenomena, and remote sensing observations are available across a range of spatial, temporal, and spectral resolutions. A growing class of models, based on the physics of magmatic systems, are making use of these expanding datastreams, providing probabilistic assessments of such parameters as magma supply, volatile content, and eruption duration. To what extent, however, do these developments heighten our ability to identify eruption precursors? The advent of better data and new models provides an opportunity to reexamine our understanding of pre-eruption unrest, as well as our ability to detect and recognize it as such. An idealized model of the buildup to a volcanic eruption might include magma ascent from a deep source region and accumulation in the mid- to upper crust in the preceding months to years. The process might be manifested by surface inflation and deep long-period earthquakes, and accompanied by an increase in CO2 emissions. As magma continues to accumulate, distal volcano-tectonic earthquakes may result as stress builds on nearby faults, H2S emissions may increase as sulfur in a shallow reservoir is hydrolyzed by groundwater, and fumarole and spring temperatures may increase and show changes in chemistry. In the days to hours before an eruption, sudden changes in the rate and style of earthquakes (including repeating earthquakes and tremor) and deformation may occur as the magma reservoir ruptures and magma moves laterally or vertically. Phreatic eruptions might result as ascending magma comes into contact with groundwater, and SO2 emissions might increase as the path between the magma and surface dries out. How often does such a sequence actually occur? Relatively few volcanoes are comprehensively monitored prior to obvious expressions of unrest, so this is not

  3. Os conflitos dos últimos 25 anos (I)

    OpenAIRE

    Moita, Luis

    2005-01-01

    Existem razões para admitir que as grandes transformações do ordenamento internacional têm estado associadas a guerras. Foi assim com a Guerra dos Trinta Anos, que não se limitou a um conflito religioso entre católicos e protestantes, mas constituiu uma guerra internacional de grande dimensão, envolvendo a Suécia, a França e o Império dos Habsburgos, e dela resultou uma nova Europa progressivamente assente em Estados nações. Foi assim com as guerras revolucionárias francesas e as do período n...

  4. Estudo do perfil dos turistas luxemburgueses

    OpenAIRE

    Leal, Kelen

    2012-01-01

    Dissertação de Mestrado em Marketing e Promoção Turística apresentada à ESTM - Escola Superior de Turismo e Tecnologia do Mar do Instituto Politécnico de Leiria Perante a atual evolução dos mercados turísticos e a mudança no comportamento do turista, torna-se fundamental conhecer profundamente as necessidades, as motivações e as preferências dos consumidores-turistas, de modo a obter uma eficaz capacidade de resposta às necessidades e preferências da procura. Com o aumento da competitiv...

  5. OS DIREITOS DOS TRABALHADORES COMO DIREITOS FUNDAMENTAIS

    OpenAIRE

    Vecchi, Ipojucan Demétrius

    2012-01-01

    O objetivo do presente texto é tentar responder, sumariamente diante das limitações próprias de um artigo, ao seguinte questionamento: quais as consequências do reconhecimento dos direitos dos trabalhadores como direitos fundamentais albergados pela Constituição Federal Brasileira de 1988? No momento em que a Ordem Constitucional de um Estado Democrático de Direito, fundado na dignidade humana e no valor social do trabalho, entre outros princípios fundamentais, eleva ao patamar de direitos fu...

  6. Pair Fireball Precursors of Neutron Star Mergers

    CERN Document Server

    Metzger, Brian D

    2016-01-01

    If at least one neutron star (NS) is magnetized in a binary NS merger, then the orbital motion of the conducting companion through its dipole field during the final inspiral induces a strong voltage and current along the magnetic field lines connecting the two objects. If a modest fraction eta of the electromagnetic power extracted during the inspiral is used to accelerate relativistic particles, the resulting gamma-ray emission in such a compact volume will result in the formation of a thermal electron-positron pair fireball. Applying the steady-state pair wind model of Paczynski (1986), we quantify the luminosities and temperatures of the precursor fireball and its detectability with gamma-ray satellites. Under the assumption that eta ~ 1, the gamma-ray detection horizon of Dmax ~ 20(Bd/1e14 G) is much closer than the Advanced LIGO/Virgo horizon of 200 Mpc, unless the surface magnetic field of the NS is very strong, Bd > 1e15 G. Given the quasi-isotropic nature of the emission, a sub-population of mergers w...

  7. Kaolin Geopolymer as Precursor to Ceramic Formation

    Directory of Open Access Journals (Sweden)

    Jaya Nur Ain

    2016-01-01

    Full Text Available This paper introduced the potential application of kaolin geopolymer as ceramic precursor. This is one of the alternatives to produce high strength ceramic at a slightly lower temperature. Upon sintering the conversion of geopolymer to ceramic occur. The kaolin used were characterized using XRF and has plate-like structure upon investigating through microstructural analysis. Geopolymer mixture is produced using 12 M NaOH molarity with the Na2SiO3/NaOH ratio of 0.24. The sintering temperature used were ranging from 900 °C to 1200 °C. The flexural strength showed the highest value of 88.47 MPa when sintered at 1200 °C. The combination of geopolymerization and sintering has attributed to the strength increment as temperature increased. The density is observed to increase with increasing sintering temperature due to the appearance of the close pores in the structure. Sintering of the geopolymer resulted in the formation of liquid phase, which enables the joining of particles to produce dense microstructure.

  8. Pair fireball precursors of neutron star mergers

    Science.gov (United States)

    Metzger, Brian D.; Zivancev, Charles

    2016-10-01

    If at least one neutron star (NS) is magnetized in a binary NS merger, then the orbital motion of the conducting companion during the final inspiral induces a strong voltage and current along the magnetic field lines connecting the NSs. If a modest fraction η of the extracted electromagnetic power extracted accelerates relativistic particles, the resulting gamma-ray emission a compact volume will result in the formation of an electron-positron pair fireball. Applying a steady-state pair wind model, we quantify the detectability of the precursor fireball with gamma-ray satellites. For η ˜ 1 the gamma-ray detection horizon of Dmax ≈ 10(Bd/1014 G)3/4 Mpc is much closer than the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO)/Virgo horizon of 200 Mpc, unless the NS surface magnetic field strength is very large, B_d ≲ 10^{15} G. Given the quasi-isotropic nature of the emission, mergers with weaker NS fields could contribute a nearby population of short gamma-ray bursts. Power not dissipated close to the binary is carried to infinity along the open field lines by a large-scale Poynting flux. Reconnection within this outflow, well outside of the pair photosphere, provides a potential site for non-thermal emission, such as a coherent millisecond radio burst.

  9. Assimilation of NAD(+) precursors in Candida glabrata.

    Science.gov (United States)

    Ma, Biao; Pan, Shih-Jung; Zupancic, Margaret L; Cormack, Brendan P

    2007-10-01

    The yeast pathogen Candida glabrata is a nicotinamide adenine dinucleotide (NAD(+)) auxotroph and its growth depends on the environmental supply of vitamin precursors of NAD(+). C. glabrata salvage pathways defined in this article allow NAD(+) to be synthesized from three compounds - nicotinic acid (NA), nicotinamide (NAM) and nicotinamide riboside (NR). NA is salvaged through a functional Preiss-Handler pathway. NAM is first converted to NA by nicotinamidase and then salvaged by the Preiss-Handler pathway. Salvage of NR in C. glabrata occurs via two routes. The first, in which NR is phosphorylated by the NR kinase Nrk1, is independent of the Preiss-Handler pathway. The second is a novel pathway in which NR is degraded by the nucleosidases Pnp1 and Urh1, with a minor role for Meu1, and ultimately converted to NAD(+) via the nicotinamidase Pnc1 and the Preiss-Handler pathway. Using C. glabrata mutants whose growth depends exclusively on the external NA or NR supply, we also show that C. glabrata utilizes NR and to a lesser extent NA as NAD(+) sources during disseminated infection.

  10. Formation of biomolecule precursors in space

    Energy Technology Data Exchange (ETDEWEB)

    Geppert, W D [Department of Physics, Stockholm University, Alba Nova, Roslagstullbacken 21, SE-10691, Stockholm (Sweden); Vigren, E [Department of Physics, Stockholm University, Alba Nova, Roslagstullbacken 21, SE-10691, Stockholm (Sweden); Hamberg, M [Department of Physics, Stockholm University, Alba Nova, Roslagstullbacken 21, SE-10691, Stockholm (Sweden); Zhaunerchyk, V [Department of Physics, Stockholm University, Alba Nova, Roslagstullbacken 21, SE-10691, Stockholm (Sweden); Thomas, R D [Department of Physics, Stockholm University, Alba Nova, Roslagstullbacken 21, SE-10691, Stockholm (Sweden); Kaminska, M [Institute of Physics, Swieetokrzyska Academy, ul. Swieokrzyska 15, PL-25406, Kielce (Poland); Millar, T J [Astrophysics Research Centre, Queen' s University Belfast, BT7 1NN, Belfast, Northern Ireland (United Kingdom); Semaniak, J [Institute of Physics, Swieetokrzyska Academy, ul. Swieokrzyska 15, PL-25406, Kielce (Poland); Roberts, H [Astrophysics Research Centre, Queen' s University Belfast, BT7 1NN, Belfast, Northern Ireland (United Kingdom); Hellberg, F [Department of Physics, Stockholm University, Alba Nova, Roslagstullbacken 21, SE-10691, Stockholm (Sweden); Oesterdahl, F [Department of Physics, Royal Institute of Technology, Alba Nova, Roslagstullbacken 21, SE-10691, Stockholm (Sweden); Ehlerding, A [Department of Physics, Stockholm University, Alba Nova, Roslagstullbacken 21, SE-10691, Stockholm (Sweden); Larsson, M [Department of Physics, Stockholm University, Alba Nova, Roslagstullbacken 21, SE-10691, Stockholm (Sweden)

    2007-11-15

    Alcohols and nitriles not only play an important role as templates for synthesis of larger molecules in the interstellar medium and planetary atmospheres, but they can also be regarded as precursors for biomolecules. Alcohols can form carbohydrates through reaction with HCO and nitriles can be hydrolysed to amino acids in aqueous solutions, which is the final step of the well-known Strecker synthesis. Therefore the question of the pathways of formation of alcohols and nitriles and the efficiency and the product distribution of their subsequent degradation reactions in the above-mentioned astrophysical environments is of great interest. In both processes dissociative recombination reactions of protonated nitriles and alcohols may play a major role and are included in models of interstellar clouds and planetary atmospheres. However, the reaction rate coefficients and product branching ratios for the majority of these processes are so far still unknown, which adversely affects the quality of predictions of model calculations. In this Contribution, we therefore present branching ratios and rate constants of the dissociative recombination of protonated methanol (CH{sub 3}OH{sub 2}), as well as protonated acetonitrile (CH{sub 3}CNH{sup +}), acrylonitrile (C{sub 2}H{sub 3}CNH{sup +}) and cyanoacetylene (HC{sup 3}NH{sup +}). The impact of the obtained new data on model calculations of abundances of important interstellar molecules in dark clouds is discussed.

  11. Biodegradable mesoporous delivery system for biomineralization precursors

    Science.gov (United States)

    Yang, Hong-ye; Niu, Li-na; Sun, Jin-long; Huang, Xue-qing; Pei, Dan-dan; Huang, Cui; Tay, Franklin R

    2017-01-01

    Scaffold supplements such as nanoparticles, components of the extracellular matrix, or growth factors have been incorporated in conventional scaffold materials to produce smart scaffolds for tissue engineering of damaged hard tissues. Due to increasing concerns on the clinical side effects of using large doses of recombinant bone-morphogenetic protein-2 in bone surgery, it is desirable to develop an alternative nanoscale scaffold supplement that is not only osteoinductive, but is also multifunctional in that it can perform other significant bone regenerative roles apart from stimulation of osteogenic differentiation. Because both amorphous calcium phosphate (ACP) and silica are osteoinductive, a biodegradable, nonfunctionalized, expanded-pore mesoporous silica nanoparticle carrier was developed for loading, storage, and sustained release of a novel, biosilicification-inspired, polyamine-stabilized liquid precursor phase of ACP for collagen biomineralization and for release of orthosilicic acid, both of which are conducive to bone growth. Positively charged poly(allylamine)-stabilized ACP (PAH-ACP) could be effectively loaded and released from nonfunctionalized expanded-pore mesoporous silica nanoparticles (pMSN). The PAH-ACP released from loaded pMSN still retained its ability to infiltrate and mineralize collagen fibrils. Complete degradation of pMSN occurred following unloading of their PAH-ACP cargo. Because PAH-ACP loaded pMSN possesses relatively low cytotoxicity to human bone marrow-derived mesenchymal stem cells, these nanoparticles may be blended with any osteoconductive scaffold with macro- and microporosities as a versatile scaffold supplement to enhance bone regeneration. PMID:28182119

  12. Bone formation on synthetic precursors of hydroxyapatite.

    Science.gov (United States)

    Suzuki, O; Nakamura, M; Miyasaka, Y; Kagayama, M; Sakurai, M

    1991-05-01

    The aim of this study was to investigate the reaction of skeletal tissue to various synthetic calcium phosphate (Ca-P) compounds in vivo. Five synthetic Ca-P compounds were implanted into the subperiosteal area of the calvaria of 7-week-old BALB/c mice for one to 15 weeks. Synthetic compounds were dicalcium phosphate (DCP), octacalcium phosphate (OCP), amorphous calcium phosphate (ACP), Ca-deficient hydroxyapatite and hydroxyapatile (HA). Implanted DCP, OCP and ACP were found to be converted to apatitic phase by x-ray microdiffraction analysis using undecalcified specimens. Structure of bone was found out on all of Ca-P compounds eventually at late stage under the light microscope, but the rate of bone formation calculated from a number of experiments varied on respective synthetic Ca-P compound. It was high as 80% for DCP, OCP and ACP, but was low as 5.6% for Ca-deficient HA, and no reaction was found for HA at the stage of 3 weeks. Fine filaments and granular materials in the newly formed bone matrix were detected at 7 days around the remnants of OCP particles which already converted to apatitic phase by ultrastructural study of decalcified specimens. These structures were very similar to the components of bone nodules seen in intramembranous osteogenesis. It is postulated that the precursors of HA have an important role in intramembranous osteogenesis.

  13. Robotic Precursor Missions for Mars Habitats

    Science.gov (United States)

    Huntsberger, Terry; Pirjanian, Paolo; Schenker, Paul S.; Trebi-Ollennu, Ashitey; Das, Hari; Joshi, Sajay

    2000-07-01

    Infrastructure support for robotic colonies, manned Mars habitat, and/or robotic exploration of planetary surfaces will need to rely on the field deployment of multiple robust robots. This support includes such tasks as the deployment and servicing of power systems and ISRU generators, construction of beaconed roadways, and the site preparation and deployment of manned habitat modules. The current level of autonomy of planetary rovers such as Sojourner will need to be greatly enhanced for these types of operations. In addition, single robotic platforms will not be capable of complicated construction scenarios. Precursor robotic missions to Mars that involve teams of multiple cooperating robots to accomplish some of these tasks is a cost effective solution to the possible long timeline necessary for the deployment of a manned habitat. Ongoing work at JPL under the Mars Outpost Program in the area of robot colonies is investigating many of the technology developments necessary for such an ambitious undertaking. Some of the issues that are being addressed include behavior-based control systems for multiple cooperating robots (CAMPOUT), development of autonomous robotic systems for the rescue/repair of trapped or disabled robots, and the design and development of robotic platforms for construction tasks such as material transport and surface clearing.

  14. Formation of biomolecule precursors in space

    Science.gov (United States)

    Geppert, W. D.; Vigren, E.; Hamberg, M.; Zhaunerchyk, V.; Thomas, R. D.; Kamińska, M.; Millar, T. J.; Semaniak, J.; Roberts, H.; Hellberg, F.; Österdahl, F.; Ehlerding, A.; Larsson, M.

    2007-11-01

    Alcohols and nitriles not only play an important role as templates for synthesis of larger molecules in the interstellar medium and planetary atmospheres, but they can also be regarded as precursors for biomolecules. Alcohols can form carbohydrates through reaction with HCO and nitriles can be hydrolysed to amino acids in aqueous solutions, which is the final step of the well-known Strecker synthesis. Therefore the question of the pathways of formation of alcohols and nitriles and the efficiency and the product distribution of their subsequent degradation reactions in the above-mentioned astrophysical environments is of great interest. In both processes dissociative recombination reactions of protonated nitriles and alcohols may play a major role and are included in models of interstellar clouds and planetary atmospheres. However, the reaction rate coefficients and product branching ratios for the majority of these processes are so far still unknown, which adversely affects the quality of predictions of model calculations. In this Contribution, we therefore present branching ratios and rate constants of the dissociative recombination of protonated methanol (CH3OH2), as well as protonated acetonitrile (CH3CNH+), acrylonitrile (C2H3CNH+) and cyanoacetylene (HC3NH+). The impact of the obtained new data on model calculations of abundances of important interstellar molecules in dark clouds is discussed.

  15. Precursors to suicidality and violence on antidepressants

    DEFF Research Database (Denmark)

    Bielefeldt, Andreas Ø; Danborg, Pia B; Gøtzsche, Peter C

    2016-01-01

    OBJECTIVE: To quantify the risk of suicidality and violence when selective serotonin and serotonin-norepinephrine reuptake inhibitors are given to adult healthy volunteers with no signs of a mental disorder. DESIGN: Systematic review and meta-analysis. MAIN OUTCOME MEASURE: Harms related to suici......OBJECTIVE: To quantify the risk of suicidality and violence when selective serotonin and serotonin-norepinephrine reuptake inhibitors are given to adult healthy volunteers with no signs of a mental disorder. DESIGN: Systematic review and meta-analysis. MAIN OUTCOME MEASURE: Harms related...... to suicidality, hostility, activation events, psychotic events and mood disturbances. SETTING: Published trials identified by searching PubMed and Embase and clinical study reports obtained from the European and UK drug regulators. PARTICIPANTS: Double-blind, placebo-controlled trials in adult healthy volunteers...... that reported on suicidality or violence or precursor events to suicidality or violence. RESULTS: A total of 5787 publications were screened and 130 trials fulfilled our inclusion criteria. The trials were generally uninformative; 97 trials did not report the randomisation method, 75 trials did not report any...

  16. Bacterial Cellular Materials as Precursors of Chloroform

    Science.gov (United States)

    Wang, J.; Ng, T.; Zhang, Q.; Chow, A. T.; Wong, P.

    2011-12-01

    The environmental sources of chloroform and other halocarbons have been intensively investigated because their effects of stratospheric ozone destruction and environmental toxicity. It has been demonstrated that microorganisms could facilitate the biotic generation of chloroform from natural organic matters in soil, but whether the cellular materials itself also serves as an important precursor due to photo-disinfection is poorly known. Herein, seven common pure bacterial cultures (Acinetobacter junii, Aeromonas hydrophila, Bacillus cereus, Bacillus substilis, Escherichia coli, Shigella sonnei, Staphylococcus sciuri) were chlorinated to evaluate the yields of chloroform, dibromochloromethane, dichlorobromomethane, and bromoform. The effects of bromide on these chemical productions and speciations were also investigated. Results showed that, on average, 5.64-36.42 μg-chloroform /mg-C were generated during the bacterial chlorination, in similar order of magnitude to that generated by humic acid (previously reported as 78 μg-chloroform/mg-C). However, unlike humic acid in water chlorination, chloroform concentration did not simply increase with the total organic carbon in water mixture. In the presence of bromide, the yield of brominated species responded linearly to the bromide concentration. This study provides useful information to understand the contributions of chloroform from photodisinfection processes in coastal environments.

  17. Comparison studies of ozone precursors in Phoenix, Arizona

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, C.; Guyton, J.; Lee, C.P. [Arizona Dept. of Environmental Quality, Phoenix, AZ (United States); Parmar, S. [Atmospheric Analysis and Consulting Co., Ventura, CA (United States)

    1994-12-31

    This paper will present the comparison of the ozone precursors monitoring program for Phoenix, Arizona during 1992 and 1993. Specific details and methodologies will be presented involving collection of air samples and analysis of speciated measurements for reactive VOC and carbonyl precursors responsible for ozone formation. Quality control and quality assurance techniques will also be discussed.

  18. The electromagnetic Brillouin precursor in one-dimensional photonic crystals

    NARCIS (Netherlands)

    Uitham, R.; Hoenders, B. J.

    2008-01-01

    We have calculated the electromagnetic Brillouin precursor that arises in a one-dimensional photonic crystal that consists of two homogeneous slabs which each have a single electron resonance. This forerunner is compared with the Brillouin precursor that arises in a homogeneous double-electron reson

  19. The electromagnetic Brillouin precursor in one-dimensional photonic crystals

    NARCIS (Netherlands)

    Uitham, R.; Hoenders, B. J.

    2008-01-01

    We have calculated the electromagnetic Brillouin precursor that arises in a one-dimensional photonic crystal that consists of two homogeneous slabs which each have a single electron resonance. This forerunner is compared with the Brillouin precursor that arises in a homogeneous double-electron

  20. Classifying the tropospheric precursor patterns of sudden stratospheric warmings

    Science.gov (United States)

    Bao, Ming; Tan, Xin; Hartmann, Dennis L.; Ceppi, Paulo

    2017-08-01

    Classifying the tropospheric precursor patterns of sudden stratospheric warmings (SSWs) may provide insight into the different physical mechanisms of SSWs. Based on 37 major SSWs during the 1958-2014 winters in the ERA reanalysis data sets, the self-organizing maps method is used to classify the tropospheric precursor patterns of SSWs. The cluster analysis indicates that one of the precursor patterns appears as a mixed pattern consisting of the negative-signed Western Hemisphere circulation pattern and the positive phase of the Pacific-North America pattern. The mixed pattern exhibits higher statistical significance as a precursor pattern of SSWs than other previously identified precursors such as the subpolar North Pacific low, Atlantic blocking, and the western Pacific pattern. Other clusters confirm northern European blocking and Gulf of Alaska blocking as precursors of SSWs. Linear interference with the climatological planetary waves provides a simple interpretation for the precursors. The relationship between the classified precursor patterns of SSWs and ENSO phases as well as the types of SSWs is discussed.

  1. Topographical and Functional Properties of Precursors to Severe Problem Behavior

    Science.gov (United States)

    Fahmie, Tara A.; Iwata, Brian A.

    2011-01-01

    A literature search identified 17 articles reporting data on 34 subjects who engaged in precursors to severe problem behavior, which we examined to identify topographical and functional characteristics. Unintelligible vocalization was the most common precursor to aggression (27%) and property destruction (29%), whereas self- or nondirected…

  2. Precursors of Short GRBs Registered by SPI-ACS/INTEGRAL

    Science.gov (United States)

    Minaev, P.; Pozanenko, A.

    2016-10-01

    We have searched for precursors in light curves of short gamma-ray bursts registered by SPI-ACS/INTEGRAL in 2002-2014. The portion of short bursts with precursor activity will be less than 0.4% from all short bursts registered by SPI-ACS.

  3. Effects of rhythmic precursors on perception of stress/syllabicity

    Science.gov (United States)

    Stilp, Christian E.; Kluender, Keith R.

    2005-09-01

    Rhythmic structure is a common property of many environmental sounds including speech. Here, perceptual effects of preceding rhythmic context are assessed in experiments employing edited words for which perceived stress/syllabicity are assessed. A series of edited naturally spoken words varying perceptually from ``polite'' to ``plight,'' was created by deleting initial-vowel glottal pulses from a recording of ``polite.'' Words were identified following nonspeech precursor sequences having either trochaic (strong-weak) or iambic (weak-strong) rhythmic patterns. Precursors consisted of a harmonic spectrum (-6-dB/octave slope) filtered by four sinusoidally modulated single-pole filters. Trochaic (strong-weak) and iambic (weak-strong) rhythmic patterns were created by varying amplitude, pitch, and duration in successive segments (akin to beats) of the precursors. Precursors were comprised of two to six repetitions of these patterns. Following trochaic precursors, listeners were more likely to report hearing ``polite'' (iambic). This pattern of results indicates that perception did not assimilate to precursor pattern, consistent with rhythmic expectancy. Instead, perception shifted in a way that contrasts with precursor temporal pattern. Additional results with precursors that are more and less like speech are being conducted to further understand how auditory perception adjusts for temporal and spectral regularities. [Work supported by NIDCD.

  4. Human embryonic epidermis contains a diverse Langerhans cell precursor pool.

    Science.gov (United States)

    Schuster, Christopher; Mildner, Michael; Mairhofer, Mario; Bauer, Wolfgang; Fiala, Christian; Prior, Marion; Eppel, Wolfgang; Kolbus, Andrea; Tschachler, Erwin; Stingl, Georg; Elbe-Bürger, Adelheid

    2014-02-01

    Despite intense efforts, the exact phenotype of the epidermal Langerhans cell (LC) precursors during human ontogeny has not been determined yet. These elusive precursors are believed to migrate into the embryonic skin and to express primitive surface markers, including CD36, but not typical LC markers such as CD1a, CD1c and CD207. The aim of this study was to further characterize the phenotype of LC precursors in human embryonic epidermis and to compare it with that of LCs in healthy adult skin. We found that epidermal leukocytes in first trimester human skin are negative for CD34 and heterogeneous with regard to the expression of CD1c, CD14 and CD36, thus contrasting the phenotypic uniformity of epidermal LCs in adult skin. These data indicate that LC precursors colonize the developing epidermis in an undifferentiated state, where they acquire the definitive LC marker profile with time. Using a human three-dimensional full-thickness skin model to mimic in vivo LC development, we found that FACS-sorted, CD207(-) cord blood-derived haematopoietic precursor cells resembling foetal LC precursors but not CD14(+)CD16(-) blood monocytes integrate into skin equivalents, and without additional exogenous cytokines give rise to cells that morphologically and phenotypically resemble LCs. Overall, it appears that CD14(-) haematopoietic precursors possess a much higher differentiation potential than CD14(+) precursor cells.

  5. Geometrizing configurations. Heinrich Hertz and his mathematical precursors

    DEFF Research Database (Denmark)

    Lützen, Jesper

    1999-01-01

    A comparison between the methods used by Heinrich hertz and his mathematician precursors such as Liouville, Lipschitz and Darboux in order to apply differential geometry in mechanics......A comparison between the methods used by Heinrich hertz and his mathematician precursors such as Liouville, Lipschitz and Darboux in order to apply differential geometry in mechanics...

  6. Precursors to Aggression Are Evident by 6 Months of Age

    Science.gov (United States)

    Hay, Dale F.; Waters, Cerith S.; Perra, Oliver; Swift, Naomi; Kairis, Victoria; Phillips, Rebecca; Jones, Roland; Goodyer, Ian; Harold, Gordon; Thapar, Anita; van Goozen, Stephanie

    2014-01-01

    We tested the hypothesis that developmental precursors to aggression are apparent in infancy. Up to three informants rated 301 firstborn infants for early signs of anger, hitting and biting; 279 (93%) were assessed again as toddlers. Informants' ratings were validated by direct observation at both ages. The precursor behaviours were…

  7. Simple asymptotic forms for Sommerfeld and Brillouin precursors

    CERN Document Server

    Macke, Bruno

    2012-01-01

    We examine from a physical viewpoint the classical problem of the propagation of a causal optical field in a dense Lorentz-medium when the propagation distance is such that the medium is opaque in a broad spectral region including the frequency of the optical carrier. The transmitted signal is then reduced to the celebrated precursors of Sommerfeld and Brillouin, well separated in time. In these conditions, we obtain explicit analytical expressions of the first (Sommerfeld) precursor, which only depend on the nature and the importance of the initial discontinuity of the incident field, and we show that the second (Brillouin) precursor has a Gaussian or Gaussian-derivative shape, depending whether the time-integral (algebraic area) of the incident field differs or not from zero. We demonstrate that the Brillouin precursor that has been actually observed in a Debye medium at decimetric wavelengths is also Gaussian. We complete these results by establishing a more general expression of the Brillouin precursor in...

  8. Dos realizaciones prefabricadas en Bolonia/Italia

    Directory of Open Access Journals (Sweden)

    Salas, Julián

    1981-04-01

    Full Text Available Se describen dos obras realizadas mediante elementos prefabricados en Bolonia (Italia por la empresa Grandi Lavori. Se trata de un conjunto de tres grandes torres con proyecto del profesor Kenzo Tange y una construcción-piloto en el recinto ferial.

  9. Consistentie met MS-DOS software

    NARCIS (Netherlands)

    Olsthoorn TN

    1988-01-01

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

  10. A Teoria dos Conjuntos de Cantor

    Directory of Open Access Journals (Sweden)

    Antônio Acra Freiria

    1992-07-01

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

  11. PERFIL E EXPECTATIVAS DOS ALUNOS CONCLUINTES DOS CURSOS TECNICOS INTEGRADOS DO IFRN, CAMPUS APODI

    Directory of Open Access Journals (Sweden)

    Saara Ramila Gurgel de Oliveira

    2014-11-01

    Full Text Available Este trabalho teve por finalidade caracterizar o perfil e as expectativas dos alunos dos terceiros e quartos anos dos cursos técnicos integrado de Zootecnia e Biocombustíveis do Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Norte – Campus Apodi. A pesquisa foi realizada com 138 alunos, através da aplicação de questionários com perguntas abertas e fechadas. A análise dos dados foi realizada de maneira descritiva e os mesmos apresentados em percentuais. Os principais resultados mostraram que as mulheres são maioria (60,9% e que a idade média foi de 17,4 anos. 99,3% dos alunos afirmaram querer cursar uma faculdade e a Universidade Federal do Rio Grande do Norte foi a instituição mais citada. Os cursos mais citados pelos discentes foram: Medicina, Ciência e tecnologia, Engenharia química, Engenharia civil, Direito e Medicina veterinária. Quanto a prática profissional, 89,9% dos alunos a realizam na forma de projetos de pesquisa ou extensão e 10,1% na forma de estágios. Mais de 97% dos estudantes estão satisfeitos com as disciplinas, porém 64,5% não estão satisfeitos com a quantidade de aulas práticas dos cursos. Quanto ao mercado de trabalho, 58,8% acreditam que há boas oportunidades. Dessa forma, conclui-se que são necessárias medidas para qualificar o ensino dos alunos, todavia, as mesmas dependem de uma gestão democrática que analise a opinião de toda a comunidade escolar.

  12. Solubilidade e disponibilidade dos micronutrientes em fertilizantes

    Directory of Open Access Journals (Sweden)

    F. Vale

    1999-06-01

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

  13. A critical review of Electric Earthquake Precursors

    Directory of Open Access Journals (Sweden)

    F. Vallianatos

    2001-06-01

    Full Text Available The generation of transient electric potential prior to rupture has been demonstrated in a number of laboratory experiments involving both dry and wet rock specimens. Several different electrification effects are responsible for these observations, but how these may scale up co-operatively in large heterogeneous rock volumes, to produce observable macroscopic signals, is still incompletely understood. Accordingly, the nature and properties of possible Electric Earthquake Precursors (EEP are still inadequately understood. For a long time observations have been fragmentary, narrow band and oligo-parametric (for instance, the magnetic field was not routinely measured. In general, the discrimination of purported EEP signals relied on "experience" and ad hoc empirical rules that could be shown unable to guarantee the validity of the data. In consequence, experimental studies have produced a prolific variety of signal shape, complexity and duration but no explanation for the apparently indefinite diversity. A set of inconsistent or conflicting ideas attempted to explain such observations, including different concepts about the EEP source region (near the observer or at the earthquake focus and propagation (frequently assumed to be guided by peculiar geoelectric structure. Statistics was also applied to establish the "beyond chance" association between presumed EEP signals and earthquakes. In the absence of well constrained data, this approach ended up with intense debate and controversy but no useful results. The response of the geophysical community was scepticism and by the mid-90's, the very existence of EEP was debated. At that time, a major re-thinking of EEP research began to take place, with reformulation of its queries and objectives and refocusing on the exploration of fundamental concepts, less on field experiments. The first encouraging results began to appear in the last two years of the 20th century. Observation technologies are mature

  14. The reliability of radon as seismic precursor

    Science.gov (United States)

    Emilian Toader, Victorin; Moldovan, Iren Adelina; Ionescu, Constantin; Marmureanu, Alexandru

    2016-04-01

    Our multidisciplinary network (AeroSolSys) located in Vrancea (Curvature Carpathian Mountains) includes radon concentration monitoring in five stations. We focus on lithosphere and near surface low atmosphere phenomena using real-time information about seismicity, + / - ions, clouds, solar radiation, temperature (air, ground), humidity, atmospheric pressure, wind speed and direction, telluric currents, variations of the local magnetic field, infrasound, variations of the atmospheric electrostatic field, variations in the earth crust with inclinometers, electromagnetic activity, CO2 concentration, ULF radio wave propagation, seismo-acoustic emission, animal behavior. The main purpose is to inform the authorities about risk situation and update hazard scenarios. The radon concentration monitoring is continuously with 1 hour or 3 hours sample rate in locations near to faults in an active seismic zone characterized by intermediate depth earthquakes. Trigger algorithms include standard deviation, mean and derivative methods. We correlate radon concentration measurements with humidity, temperature and atmospheric pressure from the same equipment. In few stations we have meteorological information, too. Sometime the radon concentration has very high variations (maxim 4535 Bq/m3 from 106 Bq/m3) in short time (1 - 2 days) without being accompanied by an important earthquake. Generally the cause is the high humidity that could be generated by tectonic stress. Correlation with seismicity needs information from minimum 6 month in our case. For 10605 hours, 618 earthquakes with maxim magnitude 4.9 R, we have got radon average 38 Bq/m3 and exposure 408111 Bqh/m3 in one station. In two cases we have correlation between seismicity and radon concentration. In other one we recorded high variation because the location was in an area with multiple faults and a river. Radon can be a seismic precursor but only in a multidisciplinary network. The anomalies for short or long period of

  15. Precursor Science for the Terrestrial Planet Finder

    Science.gov (United States)

    Lawson, P. R. (Editor); Unwin, S. C. (Editor); Beichman, C. A. (Editor)

    2004-01-01

    This document outlines a path for the development of the field of extrasolar planet research, with a particular emphasis on the goals of the Terrestrial Planet Finder (TPF). Over the past decade, a new field of research has developed, the study of extrasolar planetary systems, driven by the discovery of massive planets around nearby stars. The planet count now stands at over 130. Are there Earth-like planets around nearby stars? Might any of those planets be conducive to the formation and maintenance of life? These arc the questions that TPF seeks to answer. TPF will be implemented as a suite of two space observatories, a 6-m class optical coronagraph, to be launched around 20 14, and a formation flying mid-infrared interferometer, to be launched sometime prior to 2020. These facilities will survey up to 165 or more nearby stars and detect planets like Earth should they be present in the 'habitable zone' around each star. With observations over a broad wavelength range, TPF will provide a robust determination of the atmospheric composition of planets to assess habitability and the presence of life. At this early stage of TPF's development, precursor observational and theoretical programs are essential to help define the mission, to aid our understanding of the planets that TPF could discover, and to characterize the stars that TPF will eventually study. This document is necessarily broad in scope because the significance of individual discoveries is greatly enhanced when viewed in thc context of the field as a whole. This document has the ambitious goal of taking us from our limited knowledge today, in 2004, to the era of TPF observations in the middle of the next decade. We must use the intervening years wisely. This document will be reviewed annually and updated as needed. The most recent edition is available online at http://tpf.jpl.nasa.gov/ or by email request to lawson@hucy.jpl.nasa.gov

  16. PRECOMBUSTION REMOVAL OF HAZARDOUS AIR POLLUTANT PRECURSORS

    Energy Technology Data Exchange (ETDEWEB)

    Unknown

    2000-10-09

    In response to growing environmental concerns reflected in the 1990 Clean Air Act Amendment (CAAA), the United States Department of Energy (DOE) sponsored several research and development projects in late 1995 as part of an initiative entitled Advanced Environmental Control Technologies for Coal-Based Power Systems. The program provided cost-shared support for research and development projects that could accelerate the commercialization of affordable, high-efficiency, low-emission, coal-fueled electric generating technologies. Clean coal technologies developed under this program would serve as prototypes for later generations of technologies to be implemented in the industrial sector. In order to identify technologies with the greatest potential for commercial implementation, projects funded under Phase I of this program were subject to competitive review by DOE before being considered for continuation funding under Phase II. One of the primary topical areas identified under the DOE initiative relates to the development of improved technologies for reducing the emissions of air toxics. Previous studies have suggested that many of the potentially hazardous air pollutant precursors (HAPPs) occur as trace elements in the mineral matter of run-of-mine coals. As a result, these elements have the potential to be removed prior to combustion at the mine site by physical coal cleaning processes (i.e., coal preparation). Unfortunately, existing coal preparation plants are generally limited in their ability to remove HAPPs due to incomplete liberation of the mineral matter and high organic associations of some trace elements. In addition, existing physical coal cleaning plants are not specifically designed or optimized to ensure that high trace element rejections may be achieved.

  17. Molecular precursor routes to transition metal sulfides

    Science.gov (United States)

    Dinnage, Christopher Walker

    This thesis is primarily concerned with the synthesis of homoleptic early transition meta thiolates and the subsequent preparation of bulk and thin-film metal disulfides from these compounds. Chapter 1 gives an introduction into the properties, preparation procedures and uses of bulk and thin-film transition metal disulfides as well as giving an overview of early transition metal thiolates synthesied so far in the literature (for titanium, zirconium, tantalum and niobium). Chapter 2 is concerned with the synthesis of a number of ionic and neutral transition metal thiolates. The main synthetic methodologies discussed in this chapter include substitution reactions of transition metal amides and alkyls with thiols, salt metathesis reactions of transition metal chlorides with alkali metal thiolates or with a base / thiol and the use of Grignard reagents. Chapter 3 discusses the preparation of bulk transition metal disulfides using the thiolates prepared in the previous chapter via a thio "sol-gel" route. The preparation of a range of bulk metal and mixed-metal disulfides using transition metal chlorides and hexamethyldisilathiane is also discussed in this chapter. Finally, chapter 4 is concerned with the attempted preparation of thin-films of some transition metal disulfides. Decomposition studies of some of the thiolates prepared in chapter 2 are discussed using thermal gravimetric analysis. Vapour-phase deposition studies are also explored in order to test the potential of the transition metal thiolates as precursors to the disulfides. Experiments using low-pressure chemical vapour deposition and aerosol-assisted chemical vapour deposition are also described.

  18. Photospheric radius expansion in superburst precursors from neutron stars

    CERN Document Server

    Keek, L

    2012-01-01

    Thermonuclear runaway burning of carbon is in rare cases observed from accreting neutron stars as day-long X-ray flares called superbursts. In the few cases where the onset is observed, superbursts exhibit a short precursor burst at the start. In each instance, however, the data was of insufficient quality for spectral analysis of the precursor. Using data from the propane anti-coincidence detector of the PCA instrument on RXTE, we perform the first detailed time resolved spectroscopy of precursors. For a superburst from 4U 1820-30 we demonstrate the presence of photospheric radius expansion. We find the precursor to be 1.4-2 times more energetic than other short bursts from this source, indicating that the burning of accreted helium is insufficient to explain the full precursor. Shock heating would be able to account for the lacking energy. We argue that this precursor is a strong indication that the superburst starts as a detonation, and that a shock induces the precursor. Furthermore, we employ our techniq...

  19. Doublecortin in Oligodendrocyte Precursor Cells in the Adult Mouse Brain

    Science.gov (United States)

    Boulanger, Jenna J.; Messier, Claude

    2017-01-01

    Key Points Oligodendrocyte precursor cells express doublecortin, a microtubule-associated protein.Oligodendrocyte precursor cells express doublecortin, but at a lower level of expression than in neuronal precursor.Doublecortin is not associated with a potential immature neuronal phenotype in Oligodendrocyte precursor cells. Oligodendrocyte precursor cells (OPC) are glial cells that differentiate into myelinating oligodendrocytes during embryogenesis and early stages of post-natal life. OPCs continue to divide throughout adulthood and some eventually differentiate into oligodendrocytes in response to demyelinating lesions. There is growing evidence that OPCs are also involved in activity-driven de novo myelination of previously unmyelinated axons and myelin remodeling in adulthood. Considering these roles in the adult brain, OPCs are likely mobile cells that can migrate on some distances before they differentiate into myelinating oligodendrocytes. A number of studies have noted that OPCs express doublecortin (DCX), a microtubule-associated protein expressed in neural precursor cells and in migrating immature neurons. Here we describe the distribution of DCX in OPCs. We found that almost all OPCs express DCX, but the level of expression appears to be much lower than what is found in neural precursor. We found that DCX is downregulated when OPCs start expressing mature oligodendrocyte markers and is absent in myelinating oligodendrocytes. DCX does not appear to signal an immature neuronal phenotype in OPCs in the adult mouse brain. Rather, it could be involved either in cell migration, or as a marker of an immature oligodendroglial cell phenotype.

  20. Clustering chlorine reactivity of haloacetic acid precursors in inland lakes.

    Science.gov (United States)

    Zeng, Teng; Arnold, William A

    2014-01-01

    Dissolved organic matter (DOM) represents the major pool of organic precursors for harmful disinfection byproducts, such as haloacetic acids (HAAs), formed during drinking water chlorination, but much of it remains molecularly uncharacterized. Knowledge of model precursors is thus a prerequisite for understanding the more complex whole water DOM. The utility of HAA formation potential data from model DOM precursors, however, is limited due to the lack of comparability to water samples. In this study, the formation kinetics of dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), the two predominant HAA species, were delineated upon chlorination of seventeen model DOM precursors and sixty-eight inland lake water samples collected from the Upper Midwest region of the United States. Of particular interest was the finding that the DCAA and TCAA formation rate constants could be grouped into four statistically distinct clusters reflecting the core structural features of model DOM precursors (i.e., non-β-diketone aliphatics, β-diketone aliphatics, non-β-diketone phenolics, and β-diketone phenolics). A comparative approach built upon hierarchical cluster analysis was developed to gain further insight into the chlorine reactivity patterns of HAA precursors in inland lake waters as defined by the relative proximity to four model precursor clusters. This work highlights the potential for implementing an integrated kinetic-clustering approach to constrain the chlorine reactivity of DOM in source waters.

  1. Study on Nuclear Accident Precursors Using AHP and BBN

    Directory of Open Access Journals (Sweden)

    Sujin Park

    2014-01-01

    Full Text Available Most of the nuclear accident reports used to indicate the implicit precursors which are not easily quantified as underlying factors. The current Probabilistic Safety Assessment (PSA is capable of quantifying the importance of accident causes in limited scope. It was, therefore, difficult to achieve quantifiable decision-making for resource allocation. In this study, the methodology which facilitates quantifying these precursors and a case study were presented. First, four implicit precursors have been obtained by evaluating the causality and hierarchy structure of various accident factors. Eventually, it turned out that they represent the lack of knowledge. After four precursors are selected, subprecursors were investigated and their cause-consequence relationship was implemented by Bayesian Belief Network (BBN. To prioritize the precursors, the prior probability is initially estimated by expert judgment and updated upon observations. The pair-wise importance between precursors is calculated by Analytic Hierarchy Process (AHP and the results are converted into node probability tables of the BBN model. Using this method, the sensitivity and the posterior probability of each precursor can be analyzed so that it enables making prioritization for the factors. We tried to prioritize the lessons learned from Fukushima accident to demonstrate the feasibility of the proposed methodology.

  2. O magistério dos bispos e o magistério dos doutores

    Directory of Open Access Journals (Sweden)

    Zilles, Urbano

    2008-01-01

    Full Text Available Partindo de tensões recentes entre teólogos e bispos, de modo especial com a Cúria Romana, o autor expõe o papel do Magistério dos bispos e o dos teólogos na Igreja, defendendo a tese de que são dois serviços diferentes, mas complementares, ambos necessários para a vida da Igreja, como mostra a história

  3. Optimality properties of a proposed precursor to the genetic code.

    Science.gov (United States)

    Butler, Thomas; Goldenfeld, Nigel

    2009-09-01

    We calculate the optimality score of a doublet precursor to the canonical genetic code with respect to mitigating the effects of point mutations and compare our results to corresponding ones for the canonical genetic code. We find that the proposed precursor is much less optimal than that of the canonical code. Our results render unlikely the notion that the doublet precursor was an intermediate state in the evolution of the canonical genetic code. These findings support the notion that code optimality reflects evolutionary dynamics, and that if such a doublet code originally had a biochemical significance, it arose before the emergence of translation.

  4. Methods for forming particles from single source precursors

    Science.gov (United States)

    Fox, Robert V [Idaho Falls, ID; Rodriguez, Rene G [Pocatello, ID; Pak, Joshua [Pocatello, ID

    2011-08-23

    Single source precursors are subjected to carbon dioxide to form particles of material. The carbon dioxide may be in a supercritical state. Single source precursors also may be subjected to supercritical fluids other than supercritical carbon dioxide to form particles of material. The methods may be used to form nanoparticles. In some embodiments, the methods are used to form chalcopyrite materials. Devices such as, for example, semiconductor devices may be fabricated that include such particles. Methods of forming semiconductor devices include subjecting single source precursors to carbon dioxide to form particles of semiconductor material, and establishing electrical contact between the particles and an electrode.

  5. Percepções dos trabalhadores de enfermagem acerca dos cuidados paliativos

    Directory of Open Access Journals (Sweden)

    Tânia Cristina Schäfer Vasques

    2013-09-01

    Full Text Available Objetivou-se conhecer as percepções dos trabalhadores de enfermagem que atendem pacientes fora da possibilidade de cura e com risco de vida, acerca dos Cuidados Paliativos. Trata-se de pesquisa qualitativa, exploratória, descritiva. A coleta de dados ocorreu ao longo de 2011, por meio de entrevista semiestruturada, com 23 trabalhadores de enfermagem de uma Unidade de Clinica Médica de um hospital do sul do Brasil e os dados foram submetidos à análise textual discursiva. Os resultados evidenciaram duas categorias: O (desconhecimento dos trabalhadores de enfermagem sobre Cuidados Paliativos e Enquanto tem vida, tem esperança, enfocando aparente falta de conhecimento acerca dos cuidados Paliativos e da futilidade terapêutica, bem como dos sentimentos mobilizados pelos trabalhadores no cuidado aos pacientes fora da possibilidade de cura e com risco de vida. Destaca-se a relevância da educação permanente para capacitar os trabalhadores de enfermagem a partir da problemática da terminalidade vivenciada no cotidiano dos trabalhadores.

  6. MMPM - Mars MetNet Precursor Mission

    Science.gov (United States)

    Harri, A.-M.; Schmidt, W.; Pichkhadze, K.; Linkin, V.; Vazquez, L.; Uspensky, M.; Polkko, J.; Genzer, M.; Lipatov, A.; Guerrero, H.; Alexashkin, S.; Haukka, H.; Savijarvi, H.; Kauhanen, J.

    2008-09-01

    We are developing a new kind of planetary exploration mission for Mars - MetNet in situ observation network based on a new semi-hard landing vehicle called the Met-Net Lander (MNL). The eventual scope of the MetNet Mission is to deploy some 20 MNLs on the Martian surface using inflatable descent system structures, which will be supported by observations from the orbit around Mars. Currently we are working on the MetNet Mars Precursor Mission (MMPM) to deploy one MetNet Lander to Mars in the 2009/2011 launch window as a technology and science demonstration mission. The MNL will have a versatile science payload focused on the atmospheric science of Mars. Detailed characterization of the Martian atmospheric circulation patterns, boundary layer phenomena, and climatology cycles, require simultaneous in-situ measurements by a network of observation posts on the Martian surface. The scientific payload of the MetNet Mission encompasses separate instrument packages for the atmospheric entry and descent phase and for the surface operation phase. The MetNet mission concept and key probe technologies have been developed and the critical subsystems have been qualified to meet the Martian environmental and functional conditions. Prototyping of the payload instrumentation with final dimensions was carried out in 2003-2006.This huge development effort has been fulfilled in collaboration between the Finnish Meteorological Institute (FMI), the Russian Lavoschkin Association (LA) and the Russian Space Research Institute (IKI) since August 2001. Currently the INTA (Instituto Nacional de Técnica Aeroespacial) from Spain is also participating in the MetNet payload development. To understand the behavior and dynamics of the Martian atmosphere, a wealth of simultaneous in situ observations are needed on varying types of Martian orography, terrain and altitude spanning all latitudes and longitudes. This will be performed by the Mars MetNet Mission. In addition to the science aspects the

  7. Biodegradable mesoporous delivery system for biomineralization precursors

    Directory of Open Access Journals (Sweden)

    Yang HY

    2017-01-01

    Full Text Available Hong-ye Yang,1 Li-na Niu,2 Jin-long Sun,2 Xue-qing Huang,3 Dan-dan Pei,4 Cui Huang,1 Franklin R Tay5 1The State Key Laboratory Breeding Base of Basic Science of Stomatology, Key Laboratory for Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei, People’s Republic of China; 2State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases, Shaanxi Key Laboratory of Oral Diseases, Department of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi’an, Shaanxi, People’s Republic of China; 3Department of Prosthodontics, Guanghua School and Hospital of Stomatology, Guangdong Key Laboratory of Stomatology, Yat-sen University, Guangzhou, Guangdong, People’s Republic of China; 4Department of Prosthodontics, College of Stomatology, Xi’an Jiaotong University, Xi’an, Shaanxi, People’s Republic of China; 5Department of Endodontics, College of Dental Medicine, Augusta University, Augusta, GA, USA Abstract: Scaffold supplements such as nanoparticles, components of the extracellular matrix, or growth factors have been incorporated in conventional scaffold materials to produce smart scaffolds for tissue engineering of damaged hard tissues. Due to increasing concerns on the clinical side effects of using large doses of recombinant bone-morphogenetic protein-2 in bone surgery, it is desirable to develop an alternative nanoscale scaffold supplement that is not only osteoinductive, but is also multifunctional in that it can perform other significant bone regenerative roles apart from stimulation of osteogenic differentiation. Because both amorphous calcium phosphate (ACP and silica are osteoinductive, a biodegradable, nonfunctionalized, expanded-pore mesoporous silica nanoparticle carrier was developed for loading, storage, and sustained release of a novel, biosilicification-inspired, polyamine-stabilized liquid precursor phase of ACP

  8. Uso e Abuso dos Nebulizadores no Domicilio

    OpenAIRE

    Oliveira, Geogeta; Neto, Teresa; Dias, Carmelinda; Oliveira, Carmen; Paula Aguiar, Ana; Rodrigues, Cidrais; dos Santos, Lopes; Melo, Alda

    2014-01-01

    Introdução: Numerosos estudos tem vindo a demonstrar os benefícios das combinações pressurizeà metered dose inhalers (pMDI)/ câmaras expansoras comparativamente aos nebulizadores no manejo da asma infantil; no entanto, a prescrição incorrecta e o abuso dos sistemas de nebulização é frequente na prática clínica.Objectivos: Determinar a frequência de requisição dos nebulizadores para o domicílio nas crianças inscritas no Centro de Saúde da Sr.ª da Hora; caracterizar o grupo a quem foram prescri...

  9. Dos puentes. Río Tigris, Baghdag

    Directory of Open Access Journals (Sweden)

    Editorial, Equipo

    1959-04-01

    Full Text Available En el año 1953 se abrió un concurso público para la adjudicación de dos puentes sobre el río Tigris, denominados: uno Adhamiyah, y el otro, South Gate, situados dentro del casco urbano de la ciudad de Baghdad, bañada por el río. Anteriormente, sólo existían cuatro puentes para comunicar las dos márgenes del río en una zona de unos 20 km de longitud según el curso del río, complicando seriamente las comunicaciones y el tráfico creciente entre ambas márgenes.

  10. Metabolismo dos lípidos

    OpenAIRE

    Ibarguren Arizeta, Izaskun

    2011-01-01

    Esta unidade didáctica, Metabolismo dos lípidos, englóbase dentro da materia Bioquímica que se imparte na titulación de Grao en Veterinaria. No plano de estudos, a materia está integrada no módulo de formación básica común, impártese no primeiro semestre do primeiro curso, e ten una carga lectiva de 6 créditos ECTS. Así pois, os destinatarios son alumnos de primeiro curso de veterinaria. A Bioquímica estuda as bases moleculares dos seres vivos, isto é, como son, como interaccionan e a ...

  11. Dos nuevos puentes ligeros, en Alemania

    Directory of Open Access Journals (Sweden)

    Bay, Hermann

    1961-03-01

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

  12. DOS: the discrete-ordinates system. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Rhoades, W. A.; Emmett, M. B.

    1982-09-01

    The Discrete Ordinates System determines the flux of neutrons or photons due either to fixed sources specified by the user or to sources generated by particle interaction with the problem materials. It also determines numerous secondary results which depend upon flux. Criticality searches can be performed. Numerous input, output, and file manipulation facilities are provided. The DOS driver program reads the problem specification from an input file and calls various program modules into execution as specified by the input file.

  13. Defesa dos direitos humanos: sistemas regionais

    Directory of Open Access Journals (Sweden)

    Hélio Bicudo

    2003-04-01

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

  14. Efeitos tardios dos praguicidas organoclorados no homem

    Directory of Open Access Journals (Sweden)

    Nunes Mônica Vannucci

    1998-01-01

    Full Text Available Procurou-se relacionar as informações disponíveis sobre os organoclorados e os efeitos crônicos provocados pela exposição. Os compostos organoclorados são os praguicidas mais persistentes já fabricados. Embora sejam geralmente eficientes no controle das pragas, são importantes poluentes ambientais e potenciais causas de problemas de saúde para o homem, tendo sido proibidos ou controlados na maioria dos países. Com poucas exceções, os efeitos tardios desses compostos sobre a saúde humana são difíceis de detectar, em função de dificuldades metodológicas e da extrapolação dos resultados. A genotoxicidade está entre os mais sérios dos possíveis danos causados por esses compostos e merece atenção especial, devido à natureza irreversível do processo. Outro ponto a ser considerado é o aumento na incidência de alterações no desenvolvimento do trato reprodutivo e na fertilidade masculina observada nas últimas décadas provavelmente decorrente do aumento da exposição intra-uterina a compostos estrogênicos e anti-androgênicos, como os organoclorados.

  15. Precursor Parameter Identification for Insulated Gate Bipolar Transistor (IGBT) Prognostics

    Data.gov (United States)

    National Aeronautics and Space Administration — Precursor parameters have been identified to enable development of a prognostic approach for insulated gate bipolar transistors (IGBT). The IGBT were subjected to...

  16. Unconsumed precursors and couplers after formation of oxidative hair dyes

    DEFF Research Database (Denmark)

    Rastogi, Suresh Chandra; Søsted, Heidi; Johansen, Jeanne Duus

    2006-01-01

    Contact allergy to hair dye ingredients, especially precursors and couplers, is a well-known entity among consumers having hair colouring done at home or at a hairdresser. The aim of the present investigation was to estimate consumer exposure to some selected precursors (p-phenylenediamine, toluene......-2,5-diamine) and couplers (3-aminophenol, 4-aminophenol, resorcinol) of oxidative hair dyes during and after hair dyeing. Concentrations of unconsumed precursors and couplers in 8 hair dye formulations for non-professional use were investigated, under the conditions reflecting hair dyeing. Oxidative...... hair dye formation in the absence of hair was investigated using 6 products, and 2 products were used for experimental hair dyeing. In both presence and absence of hair, significant amounts of unconsumed precursors and couplers remained in the hair dye formulations after final colour development. Thus...

  17. Depression Often a Precursor to Falls in Elderly People

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_165985.html Depression Often a Precursor to Falls in Elderly People ... 26, 2017 FRIDAY, May 26, 2017 (HealthDay News) -- Depression appears to raise the risk of falls in ...

  18. Synthesis of beta alumina from aluminum hydroxide and oxyhydroxide precursors

    CSIR Research Space (South Africa)

    Van Zyl, A

    1993-02-01

    Full Text Available Two aluminium oxyhydroxides, boehmite and pseudoboehmite, and two aluminium hydroxides, bayerite and gibbsite, have been investigated as precursors for the synthesis of the solid electrolyte, beta alumina. Reaction pathways and products have been...

  19. Liquid precursor for deposition of copper selenide and method of preparing the same

    Energy Technology Data Exchange (ETDEWEB)

    Curtis, Calvin J.; Miedaner, Alexander; Franciscus Antonius Maria Van Hest, Marinus; Ginley, David S.; Hersh, Peter A.; Eldada, Louay; Stanbery, Billy J.

    2015-09-08

    Liquid precursors containing copper and selenium suitable for deposition on a substrate to form thin films suitable for semiconductor applications are disclosed. Methods of preparing such liquid precursors and methods of depositing a precursor on a substrate are also disclosed.

  20. The NAD+ precursor nicotinamide riboside decreases exercise performance in rats

    OpenAIRE

    Kourtzidis, Ioannis A.; Stoupas, Andreas T.; Gioris, Ioannis S.; Veskoukis, Aristidis S.; Margaritelis, Nikos V.; Tsantarliotou, Maria; Taitzoglou, Ioannis; Vrabas, Ioannis S.; Paschalis, Vassilis; Kyparos, Antonios; Nikolaidis, Michalis G.

    2016-01-01

    Background Nicotinamide adenine dinucleotide (NAD+) and its phosphorylated form (NADP+) are key molecules in ubiquitous bioenergetic and cellular signaling pathways, regulating cellular metabolism and homeostasis. Thus, supplementation with NAD+ and NADP+ precursors emerged as a promising strategy to gain many and multifaceted health benefits. In this proof-of-concept study, we sought to investigate whether chronic nicotinamide riboside administration (an NAD+ precursor) affects exercise perf...

  1. Catalysts in syntheses of carbon and carbon precursors

    OpenAIRE

    Mochida, Isao; Yoon, Seong-Ho; Qiao, Wenming

    2006-01-01

    Carbon materials have been applied in different fields because of their unique performances. Naturally, the physical and chemical structures of carbon precursors and carbon materials decide their properties and applications. Catalysts play a very important role in the synthesis of carbon precursors and carbon materials by controlling the molecular and compositional chemistry at the transformation of organic substrates into carbon through carbonaceous intermediates. Carbon materials of high pe...

  2. Dos museos en México

    Directory of Open Access Journals (Sweden)

    Ramírez Vázquez, P.

    1967-03-01

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

  3. Elements of the tsunami precursors' detection physics

    Science.gov (United States)

    Novik, Oleg; Ruzhin, Yuri; Ershov, Sergey; Volgin, Max; Smirnov, Fedor

    ionosphere from the buoy, balloon and satellite complexes. The balloon and buoy complexes will transmit data to a shore station over satellite link. The frequency ranges and sensitivity thresholds of all of the sensors of the LOAMS will be adapted to the characteristics of expected seismic signals according to the numerical research above. Computational methods and statistical analysis (e.g. seismic changes of coherence of spatially distributed sensors of different nature) of the recorded multidimensional time series will be used for prognostic interpretation. The multilevel recordings will provide a stable noise (e.g. ionosphere Pc pulsations, hard sea, industry) and seismic event detection. An intensive heat flow typical for tectonically active lithosphere zones may be considered as an energy source for advanced modifications of the LOAMS. The latter may be used as a warning system for continental and marine technologies, e.g. a sea bottom geothermal energy production. Indeed, seismic distraction of the nuclear power station Fukushima I demonstrates that similar technology hardly is able to solve the energy problems in seismically active regions. On the other hand, the LOAMS may be considered as a scientific observatory for development of the seaquake/tsunami precursor physics, i.e. seismo-hydro-electromagnetics.

  4. Detection of hydrogeochemical seismic precursors by a statistical learning model

    Directory of Open Access Journals (Sweden)

    L. Castellana

    2008-11-01

    Full Text Available The problem of detecting the occurrence of an earthquake precursor is faced in the general framework of the statistical learning theory. The aim of this work is both to build models able to detect seismic precursors from time series of different geochemical signals and to provide an estimate of number of false positives. The model we used is k-Nearest-Neighbor classifier for discriminating "no-disturbed signal", "seismic precursor" and "co-post seismic precursor" in time series relative to thirteen different hydrogeochemical parameters collected in water samples from a natural spring in Kamchachta (Russia peninsula. The measurements collected are ion content (Na, Cl, Ca, HCO3, H3BO3, parameters (pH, Q, T and gases (N2, CO2, CH4, O2, Ag. The classification error is measured by Leave-K-Out-Cross-Validation procedure. Our study shows that the most discriminative ions for detecting seismic precursors are Cl and Na having an error rates of 15%. Moreover, the most discriminative parameters and gases are Q and CH4 respectively, with error rate of 21%. The ions result the most informative hydrogeochemicals for detecting seismic precursors due to the peculiarities of the mechanisms involved in earthquake preparation. Finally we show that the information collected some month before the event under analysis are necessary to improve the classification accuracy.

  5. Risk Assessment of Infrastructure System of Systems with Precursor Analysis.

    Science.gov (United States)

    Guo, Zhenyu; Haimes, Yacov Y

    2016-08-01

    Physical infrastructure systems are commonly composed of interconnected and interdependent subsystems, which in their essence constitute system of systems (S-o-S). System owners and policy researchers need tools to foresee potential emergent forced changes and to understand their impact so that effective risk management strategies can be developed. We develop a systemic framework for precursor analysis to support the design of an effective and efficient precursor monitoring and decision support system with the ability to (i) identify and prioritize indicators of evolving risks of system failure; and (ii) evaluate uncertainties in precursor analysis to support informed and rational decision making. This integrated precursor analysis framework is comprised of three processes: precursor identification, prioritization, and evaluation. We use an example of a highway bridge S-o-S to demonstrate the theories and methodologies of the framework. Bridge maintenance processes involve many interconnected and interdependent functional subsystems and decision-making entities and bridge failure can have broad social and economic consequences. The precursor analysis framework, which constitutes an essential part of risk analysis, examines the impact of various bridge inspection and maintenance scenarios. It enables policy researchers and analysts who are seeking a risk perspective on bridge infrastructure in a policy setting to develop more risk informed policies and create guidelines to efficiently allocate limited risk management resources and mitigate severe consequences resulting from bridge failures.

  6. Role of neural precursor cells in promoting repair following stroke

    Institute of Scientific and Technical Information of China (English)

    Pooya DIBAJNIA; Cindi M MORSHEAD

    2013-01-01

    Stem cell-based therapies for the treatment of stroke have received considerable attention.Two broad approaches to stem cell-based therapies have been taken:the transplantation of exogenous stem cells,and the activation of endogenous neural stem and progenitor cells (together termed neural precursors).Studies examining the transplantation of exogenous cells have demonstrated that neural stem and progenitor cells lead to the most clinically promising results.Endogenous activation of neural precursors has also been explored based on the fact that resident precursor cells have the inherent capacity to proliferate,migrate and differentiate into mature neurons in the uninjured adult brain.Studies have revealed that these neural precursor cell behaviours can be activated following stroke,whereby neural precursors will expand in number,migrate to the infarct site and differentiate into neurons.However,this innate response is insufficient to lead to functional recovery,making it necessary to enhance the activation of endogenous precursors to promote tissue repair and functional recovery.Herein we will discuss the current state of the stem cell-based approaches with a focus on endogenous repair to treat the stroke injured brain.

  7. O comportamento ético dos enfermeiros dos hospitais universitários

    Directory of Open Access Journals (Sweden)

    Raimunda Medeiros Germano

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

  8. A fonética e seus precursores

    Directory of Open Access Journals (Sweden)

    Elvira Wanda Vagones

    2001-01-01

    Full Text Available

    Fazemos neste artigo um levantamento histórico sucinto das principais investigações dos autores que se interessaram pelo estudo da linguagem humana no plano de expressão, isto é, pelo estudo dos sons lingüísticos, assim como daqueles pesquisadores que, trabalhando com outras ciências (por exemplo, a fisiologia, a física, contribuíram indiretamente para o progresso dos estudos fonéticos.

  9. O mundo dos bens, vinte anos depois

    Directory of Open Access Journals (Sweden)

    Mary Douglas

    2007-12-01

    Full Text Available A partir do anúncio da reedição de seu livro O Mundo dos Bens, publicado originalmente em 1979, a autora faz uma reflexão do contexto intelectual em que sua obra foi fundamentada. Ela discute as bases da importância do estudo do consumo para a economia e para a antropologia, salientando que isso pode contribuir para alcançar o projeto de "totalidade" dos fenômenos sociais, na perspectiva de Marcel Mauss - autor que teve grande influência para O Mundo dos Bens. O artigo ainda mostra trabalhos e debates clássicos sobre o tema das trocas que contribuíram para as reflexões desenvolvidas no livro. É retomado o argumento de que a pobreza deve ser entendida como um processo de exclusão de informação e, nesse sentido, a autora expõe porque o estudo sobre o consumo é de grande valia para a antropologia.Taking into account the announcement of the re-edition of her book The World of Goods, originally published in 1979, the author develops a reflection on the intellectual context in which her work was created. She discusses the bases of the importance of Consumption Studies for Economics and Anthropology, suggesting that they help to attain the project of "totality" in the study of social phenomena, following the notion of Marcel Mauss - an author who exerted a great influence in the The World of Goods. The article also analyses classical works and discussions about exchanges that contributed to the reflections developed in the book. She resumes her central point, that is, that poverty must be understood as a process concerning the exclusion of information. In this sense, she presents the reasons the study on consumption is of great value for Anthropology.

  10. Modelagem computacional dos defeitos substitucionais na hidroxiapatita

    OpenAIRE

    Santos, Ricardo Daniel Soares

    2014-01-01

    Os compostos formados a base de fosfatos de cálcio têm sido muito utilizados em diferentes aplicações biomédicas devido a sua excelente capacidade de ser considerado como um material que apresenta importantes propriedades de bioatividade, biocompatibilidade e biofuncionalidade com os mais diversos tipos de tecidos. Dentre tipos de fosfatos, a Hidroxiapatita HAP, composto cuja fórmula [Ca10(PO4)6(OH)2] é um dos principais biomateriais cerâmicos utilizados como um material que apresenta a cap...

  11. Por uma carta dos bens fundamentais

    Directory of Open Access Journals (Sweden)

    Luigi Ferrajoli

    2010-07-01

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

  12. Anatomia da extremidade podal dos bovinos

    OpenAIRE

    Romão, Ricardo

    2006-01-01

    O presente texto serve de apoio ao curso prático de podologia bovina e, por essa razão, encontra-se estruturado essencialmente para uma sistematização da respectiva nomenclatura anatómica pelo que, para aprofundamento de alguns assuntos mais específicos, se recomenda uma leitura detalhada dos textos indicados na bibliografia. Abordaremos sobretudo a anatomia que interessa mais ao autopódio pelo que serão referidas essencialmente as estruturas anatómicas desta região ou, se extrínsecas, que te...

  13. Tutela administrativa efetiva dos direitos fundamentais sociais

    OpenAIRE

    Hachem, Daniel Wunder

    2014-01-01

    Resumo: A presente investigação parte do seguinte problema: após o advento da Constituição de 1988, a baixa efetividade dos direitos fundamentais sociais no Brasil suscitou, como reação da doutrina e da jurisprudência, uma centralização excessiva do debate em torno do Poder Judiciário como solução para a realização de tais direitos, notadamente pela via de ações judiciais individuais. Contudo, a atuação jurisdicional, embora muitas vezes seja de fato a única alternativa, tende a privilegiar d...

  14. A exigibilidade judicial dos direitos sociais

    OpenAIRE

    COLARES, Patrick Menezes

    2005-01-01

    A falta, de concretização de alguns direitos fundamentais, como os sociais de saúde e educação, que demandam certos custos para o Estado, ainda representa um desafio ao constitucionalismo brasileiro. Em decorrência, os tribunais vêm se deparando com demandas relacionadas a materialização dos referidos direitos, tais como pedidos de fornecimento de medicamentos não fornecidos pela rede pública de saúde ou a garantia de matrícula de estudante no sistema público de educação. Tratam-se assim de p...

  15. Equilibrio parcial y general: dos problemas inquietantes

    OpenAIRE

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

    2012-01-01

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

  16. Equilibrio parcial y general: dos problemas inquietantes

    OpenAIRE

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

    2012-01-01

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

  17. BALANCE DE DERECHOS EN DOS REFORMAS PENALES

    OpenAIRE

    Ana Gabriela Farías Calderón

    2012-01-01

    El artículo ofrece un comparativo entre los artículos de la Constitución referentes a la reforma penal y las legislaciones penales de Chihuahua y Nuevo León. Asimismo, con el fin de analizar la oferta de derechos en el proceso, se describen las etapas procesales penales en las dos mencionadas entidades federativas. Se concluye que la legislación de Nuevo León dista de apegarse a los preceptos constitucionales, mientras que la de Chihuahua, a pesar de algunos fallos, está más de acuerdo con és...

  18. Dos celebraciones religiosas en un mundo globalizado

    OpenAIRE

    María Iracheta; Olga Montes

    2009-01-01

    Este artículo intenta responder a la pregunta ¿cómo permanecen dos fiestas religiosas mexicanas -la de la Nuestra Señora de Tonatico, en su Santuario, ubicado en el municipio de Tonatico, Estado de México y la de la Virgen del Rosario en su iglesia del Barrio de Xochimilco, -en la ciudad de Oaxaca, capital del Estado de Oaxaca, -en el contexto de la modernización y la globalización? Tres elementos ayudan a explicar esta permanencia: la tradición, que es asumida y reproducida por el "linaje de...

  19. Los dos cuerpos de Carlos II

    OpenAIRE

    2016-01-01

    En las cortes europeas del siglo XVI coexisten dos modelos de cenotafios regios, ambos de tradición medieval. El primero muestra al monarca difunto yacente o arrodillado sobre la tumba; el segundo presenta el doble cuerpo del rey según la teología política que equipara la doble naturaleza de Cristo a la de los príncipes. En la tradición habsbúrgica predomina abrumadoramente el primer modelo, pero coincidiendo con la decadencia de la Monarquía Hispánica, y especialmente durante ...

  20. Sobre a peleja dos sujeitos da reforma, ou da reforma dos sujeitos em peleja

    Directory of Open Access Journals (Sweden)

    Gastão Wagner de Sousa Campos

    1992-01-01

    Full Text Available O presente trabalho analisa os principais impasses da reforma sanitária brasileira, bem como avalia a atuação do movimento de saúde a nível das instituições. Aplicando à saúde conceitos de Gramsci, F. Guattari e Castoriadis, com o objetivo de identificar os processos de construção da subjetividade dos trabalhadores de saúde, propõe-se caminhos para a reforma dos sujeitos sociais nas práticas de saúde e como atores de um processo político de reforma.

  1. Subcellular Distribution of Glutathione Precursors in Arabidopsis thaliana

    Science.gov (United States)

    Koffler, Barbara Eva; Maier, Romana; Zechmann, Bernd

    2011-01-01

    Abstract Glutathione is an important antioxidant and has many important functions in plant development, growth and defense. Glutathione synthesis and degradation is highly compartment-specific and relies on the subcellular availability of its precursors, cysteine, glutamate, glycine and γ-glutamylcysteine especially in plastids and the cytosol which are considered as the main centers for glutathione synthesis. The availability of glutathione precursors within these cell compartments is therefore of great importance for successful plant development and defense. The aim of this study was to investigate the compartment-specific importance of glutathione precursors in Arabidopsis thaliana. The subcellular distribution was compared between wild type plants (Col-0), plants with impaired glutathione synthesis (glutathione deficient pad2-1 mutant, wild type plants treated with buthionine sulfoximine), and one complemented line (OE3) with restored glutathione synthesis. Immunocytohistochemistry revealed that the inhibition of glutathione synthesis induced the accumulation of the glutathione precursors cysteine, glutamate and glycine in most cell compartments including plastids and the cytosol. A strong decrease could be observed in γ-glutamylcysteine (γ-EC) contents in these cell compartments. These experiments demonstrated that the inhibition of γ-glutamylcysteine synthetase (GSH1) – the first enzyme of glutathione synthesis – causes a reduction of γ-EC levels and an accumulation of all other glutathione precursors within the cells. PMID:22050910

  2. Quantification of erythroid and granulocytic precursor cells in plateletpheresis residues

    Energy Technology Data Exchange (ETDEWEB)

    Abboud, C.N.; Brennan, J.K.; Lichtman, M.A.; Nusbacher, J.

    1978-01-01

    Mononuclear cell fractions of human blood and plateletpheresis residues were compared for their content of hemopoietic precursor cells. Erythroid burst-forming units (BFU-E) averaged 560 +- 130 per ml of blood and granulocyte--monocyte colony forming units (CFU-C) averaged 240 +- 90 per ml blood. Estimates based on a blood volume of 7% of body weight indicate that the total blood pools of BFU-E and CFU-C are about 3.5 x 10/sup 6/ and 1.5 x 10/sup 6/ cells respectively. Sequential studies were performed over 3 days following one plateletpheresis in 4 donors. CFU-C and BFU-E approximately doubled between 48 and 72 hours after a plateletpheresis. During this time there was no significant alteration in the percent of null, T or B lymphocytes in blood. Thus, plateletpheresis appears to lead to a mobilization of precursor cells, which results in a transient increase in their concentration in blood. Therefore, pheresis 48 to 72 hours after an initial short-term procedure could harvest much larger numbers of precursor cells. Moreover, such techniques would put blood precursor cell content of plateletpheresis residues within reach of the precursor cell content in the volume of human marrow used for transplantation.

  3. Lugares dos mortos na cristandade ocidental

    Directory of Open Access Journals (Sweden)

    Cláudia Rodrigues

    2013-01-01

    Full Text Available Resumo. Este artigo busca refletir sobre a forte associação entre morte e cristandade no Ocidente, buscando identificar os lugares dos mortos nos diferentes sistemas de cristandade. Propõe-se aqui a viabilidade de se pensar numa certa vinculação entre determinadas atitudes e representações diante da morte e do morrer e o sistema de cristandade vigente em determinados contextos históricos, entre fins da Antiguidade tardia e o século XX, mais especificamente em países nos quais a Igreja romana exerceu hegemonia sobre a sociedade. Procura argumentar que, enquanto predominou a modalidade “constantiniana”, os mortos faziam parte do cotidiano e a morte e foram instrumentos do projeto cristianizador. Quando este modelo de Cristandade recuou, diante da emergência da chamada “Cristandade pós-constantiniana” – na qual a Igreja não mais era braço do aparelho estatal –, os mortos tinham sido afastados da cidade dos vivos e a morte, ou melhor, o medo da morte não mais representava instrumento de pressão sobre a consciência do cidadão

  4. Autonomia e vulnerabilidade na vida dos adolescentes

    Directory of Open Access Journals (Sweden)

    Renata R. de Oliveira

    2007-05-01

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

  5. FOUCAULT: O SILÊNCIO DOS SUJEITOS

    Directory of Open Access Journals (Sweden)

    José Carlos Bruni

    1989-06-01

    Full Text Available Este pequeno estudo mostra como Foucault, ao romper com as filosofias tradicionais do sujeito - o marxismo, o existencialismo, o positivismo -, empenha-se na reconstituição histórico-social das tecnologias da sujeição, sem apontar os caminhos possíveis da libertação dos oprimidos. Crime e loucura surgem como figuras do mal e da desrazão, prisão e manicômio circunscrevem espaços da exclusão total, instituições estratégicas para se compreender os fundamentos da ordem social. Recusando-se a dar voz ao silêncio dos sujeitos, Foucault coloca, de modo radical, a questão da representação, convidando-nos a uma nova reflexão sobre o papel específico do intelectual e do político em geral.

  6. enoturismo no Vale dos Vinhedos/RS

    Directory of Open Access Journals (Sweden)

    Hernanda Tonini

    2008-01-01

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

  7. Partitioning tungsten between matrix precursors and chondrule precursors through relative settling

    CERN Document Server

    Hubbard, Alexander

    2016-01-01

    Recent studies of chondrites have found a tungsten isotopic anomaly between chondrules and matrix. Given the refractory nature of tungsten, this implies that W was carried into the solar nebula by at least two distinct families of pre-solar grains. The observed chondrule/matrix split requires that the distinct families were kept separate during the dust coagulation process, and that the two families of grain interacted with the chondrule formation mechanism differently. We take the co-existence of different families of solids in the same general orbital region at the chondrule-precursor size as given, and explore the requirements for them to have interacted with the chondrule formation process at significantly different rates. We show that this sorting of families of solids into chondrule and matrix destined dust had to have been at least as powerful a sorting mechanism as the relative settling of aerodynamically distinct grains at at least two scale heights above the midplane. The requirement that the chondr...

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

    OpenAIRE

    Silva, Marcílio Ângelo e

    2013-01-01

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

  9. Abordagem dos efeitos secundários dos inibidores tirosina cinase

    OpenAIRE

    Monteiro, AC

    2015-01-01

    Os slides abordam os diversos efeitos secundários dos inibidores tirosina cinase(fármacos anti-neoplásicos relativamente recentes na prática clínica) tendo em conta a sua apresentação clínica, o seu significado e a sua abordagem terapêutica.

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

    Directory of Open Access Journals (Sweden)

    Andrea Roca

    2015-04-01

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

  11. PERFIL DO COMPORTAMENTO GERENCIAL: UM ESTUDO DE CASO DOS DIRETORES DOS CENTROS DE ENSINO DA UFSM

    Directory of Open Access Journals (Sweden)

    Daniela Huppes

    2009-12-01

    Full Text Available Com o aumento das pesquisas acerca de como deve ser um líder capaz de levar sua organização para níveis mais altos de eficiência, o presente trabalho objetiva identificar o perfil de comportamento gerencial, de acordo com o modelo proposto por Yukl (1998, dos Diretores de Centro da Universidade Federal de Santa Maria (UFSM. Utilizando a metodologia qualitativa, de caráter descritivo, a pesquisa foi realizada através de entrevistas semi-estruturadas, aplicadas a cada um dos oito Diretores dos Centros de Ensino. A análise dos dados foi realizada pela análise de conteúdo. Os resultados demonstram um perfil gerencial desses Diretores muito ligado ao gerenciamento de tarefas, devido à estrutura burocrática da própria instituição. Assim, atividades como planejar, solucionar problemas, administrar conflitos e esclarecer papéis e objetivos, atendidos pela exigência da universidade, e atividades relacionadas a formas de administrar relações, como monitorar desempenho, acaba negligenciado.

  12. Trabalho em saúde mental: vivências dos profissionais diante dos resultados

    Directory of Open Access Journals (Sweden)

    Vinicius Carvalho de Vasconcellos

    2012-12-01

    Full Text Available Considerando o cenário de consolidação da reforma psiquiátrica brasileira, este artigo investigou, no contexto dos trabalhadores da saúde mental, representações relativas ao papel profissional, às vivências diante dos resultados da assistência e às expectativas do futuro profissional da Saúde, tratando igualmente da possível ligação entre esses elementos. O material empírico foi coletado por meio de oito entrevistas semiestruturadas, realizadas em um Centro de Atenção Psicossocial brasileiro, e analisado principalmente pelo referencial teórico da psicossociologia francesa. De modo geral, os resultados sugerem que a vivência de realização diante dos resultados do trabalho vincula-se ao cumprimento do papel profissional, indicando também a ligação entre esses últimos elementos e as expectativas do futuro profissional. Na discussão e nas considerações finais, ressalta-se a concepção do trabalho por meio de seus limites intrínsecos como mecanismo que atenua a frustração profissional e analisam-se as implicações das vivências relativas aos resultados no vínculo subjetivo dos profissionais com o trabalho.

  13. Experimental observation of precursor solitons in a flowing complex plasma

    Science.gov (United States)

    Jaiswal, Surabhi; Bandyopadhyay, P.; Sen, A.

    2016-04-01

    The excitation of precursor solitons ahead of a rapidly moving object in a fluid, a spectacular phenomenon in hydrodynamics that has often been observed ahead of moving ships, has surprisingly not been investigated in plasmas where the fluid model holds good for low frequency excitations such as ion acoustic waves. In this Rapid Communication we report an experimental observation of precursor solitons in a flowing dusty plasma. The nonlinear solitary dust acoustic waves (DAWs) are excited by a supersonic mass flow of the dust particles over an electrostatic potential hill. In a frame where the fluid is stationary and the hill is moving the solitons propagate in the upstream direction as precursors while wake structures consisting of linear DAWs are seen to propagate in the downstream region. A theoretical explanation of these excitations based on the forced Korteweg-deVries model equation is provided and their practical implications in situations involving a charged object moving in a plasma are discussed.

  14. Observations on the Influence of Precursor Conformations on Macrocyclization Reactions

    DEFF Research Database (Denmark)

    Hammershøj, Peter; Beldring, Klavs; Nielsen, Anders R.;

    2016-01-01

    Macrocycles hold great promise in drug discovery as an underutilized class of lead compounds. The low abundance of these molecules can, in part, be explained by the inherent difficulties in the synthesis of macrocycles and the lack of general methods for their rapid assembly. We have undertaken...... a research program aimed at developing methods for facile synthesis of macrocycles from simple precursors. The synthesis of two new cyclization precursors is described and the results of their reaction with thionyl chloride are presented and discussed. Whereas one acyclic diol smoothly underwent...

  15. 3-D rheologic model of earthquake preparation (Ⅲ): Precursor field

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    On the basis of the theory of viscoelastic displacement and strain field for the three-dimensional rheologic model of earthquake preparation, this paper mainly studies the theoretical solution of precursor field for the three-dimensional rheologic model of earthquake preparation. We derive the viscoelastic analytical expressions of the ground tilt, underground water level, earth resistivity at an arbitrary point (x, y, z) in the rheologic medium, and analyzed the earth resistivity preliminarily, providing a certain theoretical basis for the precursor analysis of seismogenic process.

  16. Synthesis of GAP and PAMMO Homopolymers from Mesylate Polymeric Precursors

    Science.gov (United States)

    Mura, Claudio; Fruci, Stefania; Lamia, Pietro; Cappello, Miriam; Filippi, Sara; Polacco, Giovanni

    2016-04-01

    In azidic binders for solid propellants, the N3 functionality is introduced by substitution of a halogen or tosyl group, but recently the mesyl group has been suggested as an alternative. The mesylate group has two advantages, mainly related to its small dimensions and low cost. Poly(glycidyl azide) and poly 3-azidomethyl-3-methyl oxetane were prepared by using both tosylate and mesylate precursors. The azidation kinetics were studied at three different temperatures while keeping all other operating parameters the same. The results confirmed the good potential of the mesylate precursors for the production of azidic binders.

  17. Contabilidade criativa e responsabilidade dos auditores

    Directory of Open Access Journals (Sweden)

    Ariovaldo dos Santos

    2003-08-01

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

  18. The Presence of Modifiable Residues in the Core Peptide Part of Precursor Nisin Is Not Crucial for Precursor Nisin Interactions with NisB- and NisC

    NARCIS (Netherlands)

    Khusainov, Rustem; Kuipers, Oscar P.

    2013-01-01

    Precursor nisin is a model posttranslationally modified precursor lantibiotic that can be structurally divided into a leader peptide sequence and a modifiable core peptide part. The nisin core peptide clearly plays an important role in the precursor nisin - nisin modification enzymes interactions, s

  19. La larga vida de dos rocas orensanas

    Directory of Open Access Journals (Sweden)

    García Quintela, Marco V.

    2011-12-01

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

  20. Ação dos sucos digestivos sobre a absorção e destino do bcg Oral

    Directory of Open Access Journals (Sweden)

    Rodnei C. Mortatti

    1986-12-01

    Full Text Available Estudou-se a ação do suco gástrico artificial e suco duodenal humano sobre a vacina BCG, bem como a absorção e destino desta após administração intragástrica em camundongos. O contato de 2 horas do bacilo com o suco gástrico provocou uma diminuição significante do consumo de oxigênio e uma moderada perda da viabilidade. O suco duodenal induziu marcante decréscimo da respiração bacilar egrande redução da viabilidade. O BCG foi marcado com carbono-14 usando-se 14C-glicerol como precursor dos lipidios micobacterianos. Níveis similares de radioatividade foram obtidos nos órgãos dos animais, 24 horas após administração intragástrica de 14C- BCG, 14C-BCG rompido por ultra-som e 14C-glicerol. Os níveis de 14C-BCG permaneceram estáveis do 6º ao 24º dia, enquanto o sonicado de 14C-BCG e 14C-glicerol definiram um processo de decaimento biológico. As curvas de biodecaimento no intestino delgado e no fígado indicaram que o processo de absorção foi desencadeado rapidamente e alcançou seu nível máximo às 24 horas, decaindo em seguida de acordo com a complexidade química do material dado aos camundongos. Não foram isolados bacilos viáveis dos órgãos dos animais que receberam BCG não marcado. Pode-se concluir, portanto, que a maioria dos bacilos foram absorvidos intactos mas não viáveis.

  1. Multiple Modes of Communication between Neurons and Oligodendrocyte Precursor Cells

    NARCIS (Netherlands)

    Maldonado, Paloma P; Angulo, María Cecilia

    2015-01-01

    The surprising discovery of bona fide synapses between neurons and oligodendrocytes precursor cells (OPCs) 15 years ago placed these progenitors as real partners of neurons in the CNS. The role of these synapses has not been established yet, but a main hypothesis is that neuron-OPC synaptic activity

  2. NASA's Accident Precursor Analysis Process and the International Space Station

    Science.gov (United States)

    Groen, Frank; Lutomski, Michael

    2010-01-01

    This viewgraph presentation reviews the implementation of Accident Precursor Analysis (APA), as well as the evaluation of In-Flight Investigations (IFI) and Problem Reporting and Corrective Action (PRACA) data for the identification of unrecognized accident potentials on the International Space Station.

  3. The isoprenoid-precursor dependence of Plasmodium spp

    NARCIS (Netherlands)

    van der Meer, Jan-Ytzen; Hirsch, Anna K. H.

    2012-01-01

    Due to the increase in resistance of Plasmodium spp. against available antimalarials, there is a need for new, effective and innovative drugs. The non-mevalonate pathway for the biosynthesis of the universal isoprenoid precursors, which is absent in humans, is suggested as an attractive source of

  4. Manganite perovskite ceramics, their precursors and methods for forming

    Science.gov (United States)

    Payne, David Alan; Clothier, Brent Allen

    2015-03-10

    Disclosed are a variety of ceramics having the formula Ln.sub.1-xM.sub.xMnO.sub.3, where 0.Itoreq.x.Itoreq.1 and where Ln is La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or Y; M is Ca, Sr, Ba, Cd, or Pb; manganite precursors for preparing the ceramics; a method for preparing the precursors; and a method for transforming the precursors into uniform, defect-free ceramics having magnetoresistance properties. The manganite precursors contain a sol and are derived from the metal alkoxides: Ln(OR).sub.3, M(OR).sub.2 and Mn(OR).sub.2, where R is C.sub.2 to C.sub.6 alkyl or C.sub.3 to C.sub.9 alkoxyalkyl, or C.sub.6 to C.sub.9 aryl. The preferred ceramics are films prepared by a spin coating method and are particularly suited for incorporation into a device such as an integrated circuit device.

  5. The telescience experiment progamme TELEX for the Columbus Precursor Flights

    Science.gov (United States)

    Jungius, C. B.; Limbourg, M. C.; Wittmann, K.; Bennett, E.

    1992-08-01

    The paper overviews the telescience experiment program TELEX developed by the Microgravity User Support Centre (MUSC) and the Belgium User Support and Operation Centre for missions such as Columbus Precursor Flights. TELEX will be used to develop, test, and demonstrate in a stepwise manner the Columbus laboratory operations concept. Special attention is given to the TELEX operations and implementation.

  6. Laser microdissection of sensory organ precursor cells of Drosophila microchaetes.

    Directory of Open Access Journals (Sweden)

    Eulalie Buffin

    Full Text Available BACKGROUND: In Drosophila, each external sensory organ originates from the division of a unique precursor cell (the sensory organ precursor cell or SOP. Each SOP is specified from a cluster of equivalent cells, called a proneural cluster, all of them competent to become SOP. Although, it is well known how SOP cells are selected from proneural clusters, little is known about the downstream genes that are regulated during SOP fate specification. METHODOLOGY/PRINCIPAL FINDINGS: In order to better understand the mechanism involved in the specification of these precursor cells, we combined laser microdissection, toisolate SOP cells, with transcriptome analysis, to study their RNA profile. Using this procedure, we found that genes that exhibit a 2-fold or greater expression in SOPs versus epithelial cells were mainly associated with Gene Ontology (GO terms related with cell fate determination and sensory organ specification. Furthermore, we found that several genes such as pebbled/hindsight, scabrous, miranda, senseless, or cut, known to be expressed in SOP cells by independent procedures, are particularly detected in laser microdissected SOP cells rather than in epithelial cells. CONCLUSIONS/SIGNIFICANCE: These results confirm the feasibility and the specificity of our laser microdissection based procedure. We anticipate that this analysis will give new insight into the selection and specification of neural precursor cells.

  7. College Student Stress: A Predictor of Eating Disorder Precursor Behaviors

    Science.gov (United States)

    Shelton, Virginia L.; Valkyrie, Karena T.

    2010-01-01

    Eating disorders are compulsive behaviors that can consume a person's life to the point of becoming life threatening. Previous research found stress associated with eating disorders. College can be a stressful time. If stress predicted precursor behaviors to eating disorders, then counselors would have a better chance to help students sooner. This…

  8. Carbon molecular sieve membranes prepared from porous fiber precursor

    NARCIS (Netherlands)

    Barsema, J.N.; van der Vegt, N.F.A.; Koops, G.H.; Wessling, Matthias

    2002-01-01

    Carbon molecular sieve (CMS) membranes are usually prepared from dense polymeric precursors that already show intrinsic gas separation properties. The rationale behind this approach is that the occurrence of any kind of initial porosity will deteriorate the final CMS performance. We will show that

  9. Developmental Dyslexia: Early Precursors, Neurobehavioral Markers, and Biological Substrates

    Science.gov (United States)

    Benasich, April A., Ed.; Fitch, R. Holly, Ed.

    2012-01-01

    Understanding the precursors and early indicators of dyslexia is key to early identification and effective intervention. Now there's a single research volume that brings together the very latest knowledge on the earliest stages of dyslexia and the diverse genetic, neurobiological, and cognitive factors that may contribute to it. Based on findings…

  10. Precursors to numeracy in kindergartners with specific language impairment

    NARCIS (Netherlands)

    Kleemans, M.A.J.; Segers, P.C.J.; Verhoeven, L.T.W.

    2011-01-01

    The present study investigated to what extent children with specific language impairment (SLI) differ in their early numeracy skills, when compared to normal language achieving (NLA) children. It was also explored which precursors were related to the early numeracy skills in both groups. Sixty-one

  11. Antibody-bound amyloid precursor protein upregulates ornithine decarboxylase expression

    DEFF Research Database (Denmark)

    Nilsson, Tatjana; Malkiewicz, Katarzyna; Gabrielsson, Maria

    2006-01-01

    Alzheimer's disease is a neurodegenerative disorder characterised by extracellular accumulation of the Abeta peptide, derived from the amyloid precursor protein (APP). The function of APP as a cell surface receptor was examined by ligand-mimicking using an antibody against the APP extracellular...

  12. Synthesis of new diverse macrocycles from diol precursors

    DEFF Research Database (Denmark)

    Madsen, Charlotte Marie; Hansen, Martin; Thrane, Marie V.;

    2010-01-01

    The formation of a library of diverse macrocycles with different ring sizes from two easily accessible building blocks is presented. Reacting diol precursors with electrophilic reagents lead to 17-membered sulfites and 19-membered malonates in 34–79% yield. Double-reductive amination of dialdehyd...

  13. Carbon molecular sieve membranes prepared from porous fiber precursor

    NARCIS (Netherlands)

    Barsema, Jonathan N.; Vegt, van der N.F.A.; Koops, G.H.; Wessling, M.

    2002-01-01

    Carbon molecular sieve (CMS) membranes are usually prepared from dense polymeric precursors that already show intrinsic gas separation properties. The rationale behind this approach is that the occurrence of any kind of initial porosity will deteriorate the final CMS performance. We will show that i

  14. Observations on the Influence of Precursor Conformations on Macrocyclization Reactions

    DEFF Research Database (Denmark)

    Hammershøj, Peter; Beldring, Klavs; Nielsen, Anders R.

    2016-01-01

    macrocyclization to afford a mixture of diastereomeric sulfites, subjection of the other precursor to identical reaction conditions resulted in the isolation of the linear dichloride. We hypothesize that there is a difference in the ability of the two molecules to adopt a conformation that is germane...... to macrocyclization, a proposition that is supported by conformational analyses using molecular mechanics....

  15. The isoprenoid-precursor dependence of Plasmodium spp

    NARCIS (Netherlands)

    van der Meer, Jan-Ytzen; Hirsch, Anna K. H.

    2012-01-01

    Due to the increase in resistance of Plasmodium spp. against available antimalarials, there is a need for new, effective and innovative drugs. The non-mevalonate pathway for the biosynthesis of the universal isoprenoid precursors, which is absent in humans, is suggested as an attractive source of ta

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

    Directory of Open Access Journals (Sweden)

    Wendol A Williams

    2008-05-01

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

  17. LOGÍSTICA DOS MATERIAIS NAS UNIVERSIDADES: A PARTICIPAÇÃO DOS AGENTES PATRIMONIAIS NO CONTROLE DOS BENS MÓVEIS

    OpenAIRE

    2014-01-01

    O presente artigo tem por objetivo analisar a logística dos materiais nas Universidades, principalmente na Universidade Federal de Santa Catarina, UFSC, comentando a história da implantação do modelo, onde se desenvolveu a participação dos agentes patrimoniais no controle dos bens móveis destas instituições. Trata-se de um artigo indutivo, com uma pesquisa qualitativa, apresentando narrativas e relatos observados em pesquisas bibliográficas, utilizando-se de técnica exploratória e de observaç...

  18. AVALIAÇÃO DOS MÉTODOS DE ESTUDO DOS DISCENTES

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    Ryan Luiz da Silva Oliveira

    2017-05-01

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

  19. Universidade e comunidade na perspectiva dos movimentos estudantis dos anos 1960

    Directory of Open Access Journals (Sweden)

    Luís Antonio Groppo

    2011-03-01

    Full Text Available Resumo Neste artigo, procuro discutir a práxis dos movimentos estudantis universitários dos anos 1960em relação às "comunidades" no entorno das unidades de ensino. Constata-se, primeiro, uma relativa carência de ações efetivas, principalmente porque os movimentos estudantis se preocupavam, sobretudo, com a intervenção na política nacional e nos rumos gerais da sociedade de que faziam parte. Ainda assim, na sua riqueza e complexidade, os movimentos estudantis dos anos 1960 enfrentaram a questão da relação com a "comunidade", o que se observa em projetos e propostas criativas de ação prática, revelando uma potencialidade que poderia ter sido mais bem aproveitada. Palavras-chave: movimentos estudantis; universidade; comunidade.   Abstract In this article I intend to discuss the praxis from student movements of sixties, in its relations with the "communities" in the universities ‘neighborhoods. I evidence, first, a relative failure of effective actions, principally because the student movements preoccupy, especially, with the intervention in national politic and in the general ways of their societies. Indeed, in their wealth and complexity, the student movements from the sixties confront the question of the relation with the community, what it looks in creative projects and propositions of practical action, what reveals a potentiality what can be better used. Keywords: student movements; university; community.

  20. O EQUIVALENTE EM CARBONATO DE CÁLCIO DOS CORRETIVOS DA ACIDEZ DOS SOLOS

    Directory of Open Access Journals (Sweden)

    J.C. ALCARDE

    1996-05-01

    Full Text Available Os corretivos da acidez dos solos podem ter dois equivalentes em carbonato de cálcio: um, calculado pelos teores de cálcio e magnésio utilizando a expressão: % CaO x 1,79 + % MgO x 2,48 = %ECaCO3; outro, determinado analiticamente pelo poder ou valor de neutralização. Para uma mesma amostra ambos os valores deveriam coincidir, o que raramente acontece. Diversas hipóteses foram levantadas para justificar essa diferença. Os resultados deste trabalho permitiram inferir que nem todo o cálcio e magnésio dos corretivos devem estar associados às bases quimicamente efetivas mas também a fosfato, sulfato ou outras bases de forças inexpressivas; também os constituintes neutralizantes podem estar aprisionados em cristais de outros componentes dos corretivos, como sílica por exemplo, que só são atingidos por um ataque mais enérgico da amostra. Como conclusão, a avaliação química atual dos corretivos da acidez dos solos pode não estar se compatibilizando com o comportamento agrícola desses produtos.Agricultural liming materials can have two calcium carbonate equivalents: one calculated in function of calcium and magnesium oxide percentages, by the expression: % CaO x 1,79 + % MgO x 2,48 = %ECaCO3; and the other determined analytically by the neutralization power or value. For one sample, both values should be similar, however, this rarely occurs. Several hypoteses were raised to justify the difference. Results of this research permit to infer that not all calcium and magnesium should be associated to the chemically effective bases, but they are also associated to phosphate, sulphate or other bases of inexpressive strength. It is also possible that, the neutralizing components could be captured inside cristals, like silica for example, which react only after a strong solubilization of the sample. It is concluded that the chemical evaluation of agricultural liming materials at the present time cannot explain the agronomical behaviour of

  1. Grupos de nudos con dos generadores

    Directory of Open Access Journals (Sweden)

    Christian Pommerenke

    2011-06-01

    Full Text Available Se estudian grupos de nudos que admiten una presentación con dos generadores y una relación. Decimos que una presentación �a, b | r� es palindrómica si r es una palabra palíndromo, es decir, r es una palabra que se lee lo mismo de adelante para atrás que de atrás para adelante. Estudiamos condiciones bajo las cuales es posible cambiar la presentación dada para obtener una presentación palindrómica. Probamos que si el grupo G de un nudo admite una representación fiel en un subgrupo discreto de SL(2, C, entonces G admite una presentación palindrómica. Abstract. We study knot groups that admit a presentation with two generators and one relation. We say that a presentation �a, b | r� is palindromic if r is a palindrome, that is, if r is a word that reads the same forwards and backwards. We study conditions that allow us to change the given presentation to obtain a palindromic presentation. We prove that if the knot group G admits a faithful discrete SL(2, C-representation then G admits a palindromic presentation.

  2. Las dos doncellas: padres e hijos

    Directory of Open Access Journals (Sweden)

    Stanislav Zimic

    1989-12-01

    Full Text Available Los juicios críticos acerca de esta novela corta cervantina son preponderantemente negativos: »imperfecta«; »mediocre, convencional y artificiosa«; »Una de las más endebles de la colección«;  »nearest to failure«; »escrita sin mucha gana«; bajo la influencia de la novelística italiana, »contra la voluntad y el dicho de Cervantes«, con »el  simple propósito de orden editorial y secundario de añadir una novela más a las que ya tenía escritas, para poder llegar a la docena proyectada … novela de relleno«, etc., etc. Raras veces se concede - y aun entonces más bien por indulgencia hacia el Príncipe de los Ingenios - que Las dos doncellas tiene algún atractivo literario: »como novela no pasa de un discreto artificio idealista, inocente, pálido, aunque habil en el relato a la italiana«; »the subject-matter of this novela is not particularly interesting«, aunque »the story is well constructed and presented«.

  3. Os conflitos conjugais na perspectiva dos filhos

    Directory of Open Access Journals (Sweden)

    Viviane Ribeiro Goulart

    2013-01-01

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

  4. Apendicitis neonatal: Reporte de dos casos

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    María José Maldonado

    2017-04-01

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

  5. Dos celebraciones religiosas en un mundo globalizado

    Directory of Open Access Journals (Sweden)

    María Iracheta

    2009-01-01

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

  6. Angiografia por tomografia computadorizada dos aneurismas intracranianos

    Directory of Open Access Journals (Sweden)

    Laureano Vinícius Santos

    2002-01-01

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

  7. Dos nuevas obras de Francisco Gallardo

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    Alonso de la Sierra Fernández, Lorenzo

    2001-09-01

    Full Text Available La localización de dos lienzos firmados por Francisco Gallardo, uno en Sevilla y otro en Cádiz, amplía las escasas noticias que se conocen sobre la vida y obra de este autor. El cuadro de Cádiz, de propiedad particular, es un trampantojo del tipo conocido como «rincón de taller» y sus dimensiones son 83 x 62 cms. En él destaca una estampa, sobre la que se posa una mosca, clavada al habitual fondo de tablas, y en cuya zona inferior se puede leer: «En Cádiz, año de 1720... Franco. Julo. Gallado F.». Bajo la estampa hay una cinta, sujeta con puntas y atravesada en uno de los extremos por un punzón, que sirve de soporte a una carta plegada en la cual aparece escrito: «Sr. Dn. Franco X...». La obra conservada en Sevilla, también de propiedad particular, mide 157 x 108 cms. y representa a santo Tomás de Aquino.…

  8. LAS DOS TRÍADAS DEBEJARANO

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    Jorge Iván González

    Full Text Available El artículo diseute "dos tríadas" que propone Bejarano para calificar a la teoría económica actual. La primera tríada tiene que ver con el realismo, la pertinencia y la relevancia de la teoría. Y la segunda tríada con sus dimensiones política, institucional y moral. El artículo centra la atención en esta segunda tríada, argumentando que la teoría no es apolítica, ainstitucional y amoral como afirma Bejarano. El examen crítico de la posición de Bejarano se sustenta en algunas de las tesis de: Walras, Marshall, Hicks, vickrey, Samuelson y Arrow.This article discusses the "two triads" that Bejarano has proposed in order to describe present economic theory. The first triad refers to the realism, pertinence and relevance of the theory. The second triad to its political, institutional and moral dimension. The article centers its attention on this second triad, arguing that the theory is not apolitical, uninstitutional and amoral as Bejarano states. The critical examination of Bejarano's proposition is supported on thesis of Walras, Marshall, Hicks, Vickrey, Samuelson and Arrow.

  9. Corpo, formas, movimentos e ritmo como precursores da emergência da intersubjetividade e da palavra no bebê. (Uma reflexão sobre os inícios da linguagem verbal

    Directory of Open Access Journals (Sweden)

    Bernard Golse

    Full Text Available Depois de lembrar as bases da comunicação analógica e digital, os autores apresentam as hipóteses de seu programa de pesquisa atual a respeito dos precursores corporais e comportamentais do acesso à linguagem verbal na criança. As análises do olhar, das vocalizações e dos movimentos das mãos do bebê são os principais elementos estudados nesta pesquisa colaborativa. O surgimento da intersubjetividade parece depender fundamentalmente de um equilíbrio entre os processos de desmantelamento intersensorial e de segmentação intrasensorial dos diferentes fluxos perceptivos.

  10. Whole-cell fungal transformation of precursors into dyes

    Directory of Open Access Journals (Sweden)

    Jarosz-Wilkołazka Anna

    2010-07-01

    Full Text Available Abstract Background Chemical methods of producing dyes involve extreme temperatures and unsafe toxic compounds. Application of oxidizing enzymes obtained from fungal species, for example laccase, is an alternative to chemical synthesis of dyes. Laccase can be replaced by fungal biomass acting as a whole-cell biocatalyst with properties comparable to the isolated form of the enzyme. The application of the whole-cell system simplifies the transformation process and reduces the time required for its completion. In the present work, four fungal strains with a well-known ability to produce laccase were tested for oxidation of 17 phenolic and non-phenolic precursors into stable and non-toxic dyes. Results An agar-plate screening test of the organic precursors was carried out using four fungal strains: Trametes versicolor, Fomes fomentarius, Abortiporus biennis, and Cerrena unicolor. Out of 17 precursors, nine were transformed into coloured substances in the presence of actively growing fungal mycelium. The immobilized fungal biomass catalyzed the transformation of 1 mM benzene and naphthalene derivatives in liquid cultures yielding stable and non-toxic products with good dyeing properties. The type of fungal strain had a large influence on the absorbance of the coloured products obtained after 48-hour transformation of the selected precursors, and the most effective was Fomes fomentarius (FF25. Whole-cell transformation of AHBS (3-amino-4-hydroxybenzenesulfonic acid into a phenoxazinone dye was carried out in four different systems: in aqueous media comprising low amounts of carbon and nitrogen source, in buffer, and in distilled water. Conclusions This study demonstrated the ability of four fungal strains belonging to the ecological type of white rot fungi to transform precursors into dyes. This paper highlights the potential of fungal biomass for replacing isolated enzymes as a cheaper industrial-grade biocatalyst for the synthesis of dyes and other

  11. CARBONACEOUS MATTER PRECURSORS AND METAMORPHIC CONDITIONS IN THERMALLY PROCESSED CHONDRITES

    Science.gov (United States)

    Quirico, E.; Montagnac, G.; Rouzaud, J.; Bonal, L.; Bourot-Denise, M.; Duber, S.; Reynard, B.

    2009-12-01

    Unravelling the origin of carbonaceous matter in pristine chondrites requires the understanding of the effect of post-accretion processes. In chondrites of petrologic type 3, thermal metamorphism modified to various extents the composition and structure of carbonaceous matter. Interestingly, this process controls the degree of structural order of carbonaceous matter, and clues on the thermal history of the parent body may be recovered from the physico-chemical study of carbonaceous matter. Following this framework, geothermometers based on Raman spectrometry of carbonaceous matter and covering a wide range of temperatures (100-650 °C) have been developed over recent years, both on terrestrial rocks and chondrites. While Raman data have been largely interpreted in terms of temperature, they are also the fingerprint of certain metamorphic conditions, especially in the low temperature range relevant to poorly ordered carbonaceous matter. This study investigates the Raman spectra of two series of chondritic carbonaceous matter and coal samples formed from different precursors and under different metamorphic conditions. The Raman spectra of Polyaromatic Carbonaceous Matter (PCM) from 42 chondrites and 27 coal samples, measured with visible (514 nm) and ultra-violet (244 nm) excitation wavelengths, are analyzed. The Raman spectra of low rank coals and chondrites of petrologic types 1 and 2, which contain the more disordered PCM, reflect the distinct carbon structures of their precursors. The 514 nm Raman spectra of high rank coals and chondrites of petrologic type 3 exhibit continuous and systematic spectral differences reflecting different carbon structures present during the metamorphism event. They result from differences in the chemical structures of the precursors concerning for instance the reticulation of polyaromatic units or an abundance of ether functional groups, or possibly from a lack of carbonization processes to efficiently expel oxygen heteroatoms, due

  12. Marketing de hospitalidade dos albergues da juventude no Brasil

    OpenAIRE

    Coriolano, Plínio Vidigal

    2010-01-01

    Desvenda o Modus Operandi dos Albergues da Juventude do Brasil como funcionam, como se inserem no contexto nacional e mundial, atrativos mercadológicos, estruturas organizacional e hotelaria básica da indústria de hospitalidade, marketing mix, planejamento estratégico etc. Sob o prisma dos conceitos do Marketing de Hospitalidade

  13. PREPARATION OF TANTALUM CARBIDE FROM AN ORGANOMETALLIC PRECURSOR

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    C. P. SOUZA

    1999-03-01

    Full Text Available In this work we have synthesized an organometallic oxalic precursor from tantalum oxide. This oxide was solubilized by heating with potassium hydrogen sulfate. In order to precipitate Ta2O5.nH2O, the fused mass obtained was dissolved in a sulfuric acid solution and neutralized with ammonia. The hydrated tantalum oxide precipitated was dissolved in an equimolar solution of oxalic acid/ammonium oxalate. The synthesis and the characterization of the tantalum oxalic precursor are described. Pyrolysis of the complex in a mixture of hydrogen and methane at atmospheric pressure was studied. The gas-solid reaction made it possible to obtain tantalum carbide, TaC, in the powder form at 1000oC. The natural sintering of TaC powder in an inert atmosphere at 1400°C during 10 hours, under inert atmosphere made it possible to densify the carbide to 96% of the theoretical value.

  14. Whistler damping at oblique propagation - Laminar shock precursors

    Science.gov (United States)

    Gary, S. P.; Mellott, M. M.

    1985-01-01

    This paper addresses the collisionless damping of whistlers observed as precursors standing upstream of oblique, low-Mach number terrestrial bow shocks. The linear theory of electromagnetic waves in a homogeneous Vlasov plasma with Maxwellian distribution functions and a magnetic field is considered. Numerical solutions of the full dispersion equation are presented for whistlers propagating at an arbitrary angle with respect to the magnetic field. It is demonstrated that electron Landau damping attenuates oblique whistlers and that the parameter which determines this damping is beta-e. In a well-defined range of parameters, this theory provides damping lengths which are the same order of magnitude as those observed. Thus electron Landau damping is a plausible process in the dissipation of upstream whistlers. Nonlinear plasma processes which may contribute to precursor damping are also discussed, and criteria for distinguishing among these are described.

  15. Atomic scale simulation of carbon nanotube nucleation from hydrocarbon precursors.

    Science.gov (United States)

    Khalilov, Umedjon; Bogaerts, Annemie; Neyts, Erik C

    2015-12-22

    Atomic scale simulations of the nucleation and growth of carbon nanotubes is essential for understanding their growth mechanism. In spite of over twenty years of simulation efforts in this area, limited progress has so far been made on addressing the role of the hydrocarbon growth precursor. Here we report on atomic scale simulations of cap nucleation of single-walled carbon nanotubes from hydrocarbon precursors. The presented mechanism emphasizes the important role of hydrogen in the nucleation process, and is discussed in relation to previously presented mechanisms. In particular, the role of hydrogen in the appearance of unstable carbon structures during in situ experimental observations as well as the initial stage of multi-walled carbon nanotube growth is discussed. The results are in good agreement with available experimental and quantum-mechanical results, and provide a basic understanding of the incubation and nucleation stages of hydrocarbon-based CNT growth at the atomic level.

  16. Preparation of tantalum carbide from an organometallic precursor

    Energy Technology Data Exchange (ETDEWEB)

    Souza, C.P. [Rio Grande do Norte Univ., Natal, RN (Brazil). Programa de Pos-graduacao em Geoquimica. Lab. de Termodinamica e Reatores]. E-mail: carlson at ufrnet.ufrn.br; Favotto, C.; Satre, P.; L' Honore, A.; Roubin, M. [Universite du Toulon et de Var B.P. (France). Equipe der Materiaux a Finalite Specifique. Lab. de Physicochimie du Materiaux et du Milieu Marin]. E-mail: roubin at univ-tln.fr

    1999-03-01

    In this work we have synthesized an organometallic oxalic precursor from tantalum oxide. This oxide was solubilized by heating with potassium hydrogen sulfate. In order to precipitate Ta{sub 2} O{sub 5} nH{sub 2}O, the fused mass obtained was dissolved in a sulfuric acid solution and neutralized with ammonia. The hydrated tantalum oxide precipitated was dissolved in an equimolar solution of oxalic acid/ammonium oxalate. The synthesis and the characterization of the tantalum oxalic precursor are described. Pyrolysis of the complex in a mixture of hydrogen and methane at atmospheric pressure was studied. The gas-solid reaction made it possible to obtain tantalum carbide, Ta C, in the powder form at 1000 deg C. The natural sintering of Ta C powder in an inert atmosphere at 1400 deg C during 10 hours, under inert atmosphere made it possible to density the carbide to 96% of the theoretical value. (author)

  17. Production of activated carbon from a new precursor: Molasses

    Science.gov (United States)

    Legrouri, K.; Ezzine, M.; Ichcho, S.; Hannache, H.; Denoyel, R.; Pailler, R.; Naslain, R.

    2005-03-01

    Activated carbon has been prepared from molasses, a natural precursor of vegetable origin resulting from the sugar industry in Morocco. The preparation of the activated carbon from the molasses has been carried out by impregnation of the precursor with sulfuric acid, followed by carbonization. The adsorption capacity, the BET surface area, and the pore volume of the activated carbon were determined. The micropore volume was assessed by Dubinin- Radushkevich (DR) equation. The activated materials are mainly microporous and show the type I isotherm of the Brunauer classification for nitrogen adsorption. The activation in steam yielded a carbon that contains both micropores and supermicropores. Analysis of the nitrogen isotherm by BET and DR methods established that most of obtained carbons are highly microporous, with high surface areas (≥ 1200 m2/g) and very low mesoporosity.

  18. Structural basis for precursor protein-directed ribosomal peptide macrocyclization

    Energy Technology Data Exchange (ETDEWEB)

    Li, Kunhua; Condurso, Heather L.; Li, Gengnan; Ding, Yousong; Bruner, Steven D. (Florida)

    2016-11-11

    Macrocyclization is a common feature of natural product biosynthetic pathways including the diverse family of ribosomal peptides. Microviridins are architecturally complex cyanobacterial ribosomal peptides that target proteases with potent reversible inhibition. The product structure is constructed via three macrocyclizations catalyzed sequentially by two members of the ATP-grasp family, a unique strategy for ribosomal peptide macrocyclization. Here we describe in detail the structural basis for the enzyme-catalyzed macrocyclizations in the microviridin J pathway of Microcystis aeruginosa. The macrocyclases MdnC and MdnB interact with a conserved α-helix of the precursor peptide using a novel precursor-peptide recognition mechanism. The results provide insight into the unique protein–protein interactions that are key to the chemistry, suggest an origin for the natural combinatorial synthesis of microviridin peptides, and provide a framework for future engineering efforts to generate designed compounds.

  19. Synthesis and Characterization of Poly(methylsilane) as Ceramic Precursor

    Institute of Scientific and Technical Information of China (English)

    Chen Lai; Zhang Feng-jun; Wu Shi; Sun Jin-liang; Ren Mu-su; Fan Xue-qi

    2005-01-01

    @@ 1Introduction Polysilanes are novel polymers with Si-Si catenation chain. They can be used as precursors for SiC ceramic, have important applications in anti-oxidation of C/C composites[1]. Poly(methylsilane)(PMS), which is anideal precursor to stoichiometric SiC, is synthesized by the sodium polycondensation reaction of monomer CH3SiHCl2. During the reaction, there is an initiation period. In this period there is no obvious exothermic reaction after dropping of monomer, then suddenly eruptive reaction arise and temperature goes up quickly. After the eruption, the polymerization can proceed smoothly. This phenomenon is harmful to scale-up. To solve this problem, we did relevant research, but the additive, crown ether, is expensive[2]. This paper describes the influence of naphthalene(NAPH) and p-dibromobenzene(DBB) on the reaction. Good effect is attained for these additives.

  20. Antarctic new particle formation from continental biogenic precursors

    Science.gov (United States)

    Kyrö, E.-M.; Kerminen, V.-M.; Virkkula, A.; Dal Maso, M.; Parshintsev, J.; Ruíz-Jimenez, J.; Forsström, L.; Manninen, H. E.; Riekkola, M.-L.; Heinonen, P.; Kulmala, M.

    2013-04-01

    Over Antarctica, aerosol particles originate almost entirely from marine areas, with minor contribution from long-range transported dust or anthropogenic material. The Antarctic continent itself, unlike all other continental areas, has been thought to be practically free of aerosol sources. Here we present evidence of local aerosol production associated with melt-water ponds in continental Antarctica. We show that in air masses passing such ponds, new aerosol particles are efficiently formed and these particles grow up to sizes where they may act as cloud condensation nuclei (CCN). The precursor vapours responsible for aerosol formation and growth originate very likely from highly abundant cyanobacteria Nostoc commune (Vaucher) communities of local ponds. This is the first time freshwater vegetation has been identified as an aerosol precursor source. The influence of the new source on clouds and climate may increase in future Antarctica, and possibly elsewhere undergoing accelerating summer melting of semi-permanent snow cover.

  1. Antarctic new particle formation from continental biogenic precursors

    Directory of Open Access Journals (Sweden)

    E.-M. Kyrö

    2013-04-01

    Full Text Available Over Antarctica, aerosol particles originate almost entirely from marine areas, with minor contribution from long-range transported dust or anthropogenic material. The Antarctic continent itself, unlike all other continental areas, has been thought to be practically free of aerosol sources. Here we present evidence of local aerosol production associated with melt-water ponds in continental Antarctica. We show that in air masses passing such ponds, new aerosol particles are efficiently formed and these particles grow up to sizes where they may act as cloud condensation nuclei (CCN. The precursor vapours responsible for aerosol formation and growth originate very likely from highly abundant cyanobacteria Nostoc commune (Vaucher communities of local ponds. This is the first time freshwater vegetation has been identified as an aerosol precursor source. The influence of the new source on clouds and climate may increase in future Antarctica, and possibly elsewhere undergoing accelerating summer melting of semi-permanent snow cover.

  2. Study of the Optimal Precursors for Blocking Events

    Institute of Scientific and Technical Information of China (English)

    JIANG Zhina; LUO Dehai

    2005-01-01

    The precursors of dipole blocking are obtained by a numerical approach based upon a quasi-geostrophic barotropic planetary- to synoptic-scale interaction model without topography and with a localized synopticscale wave-maker. The optimization problem related to the precursors of blocking is formulated and the nonlinear optimization method is used to examine the optimal synoptic-scale initial field successfully. The results show that the prominent characteristics of the optimal synoptic-scale initial field are that the synoptic-scale wave train structures exist upstream of the incipient blocking. In addition, the large-scale low/high eddy-forcing pattern upstream of the incipient blocking is an essential precondition for the onset of dipole blocking.

  3. Ceramic fibers from Si-B-C polymer precursors

    Science.gov (United States)

    Riccitiello, S. R.; Hsu, M. S.; Chen, T. S.

    1993-01-01

    Non-oxide ceramics such as silicon carbide (SiC), silicon nitride (Si3N4), and silicon borides (SiB4, SiB6) have thermal stability, oxidation resistance, hardness, and varied electrical properties. All these materials can be prepared in a fiber form from a suitable polymer precursor. The above mentioned fibers, when tested over a temperature range from 25 to 1400 C, experience degradation at elevated temperatures. Past work in ceramic materials has shown that the strength of ceramics containing both carbides and borides is sustained at elevated temperatures, with minimum oxidation. The work presented here describes the formation of ceramic fibers containing both elements, boron and silicon, prepared via the polymer precursor route previously reported by the authors, and discusses the fiber mechanical properties that are retained over the temperature range studied.

  4. Characterization studies of purified HgI{sub 2} precursors

    Energy Technology Data Exchange (ETDEWEB)

    Schieber, M. E-mail: Schieber@vms.huji.ac.il; Zuck, A.; Sanguinetti, S.; Montalti, M.; Braiman, M.; Melekhov, L.; Nissenbaum, J.; Grilli, E.; Guzzi, M.; Turchetta, R.; Dulinski, W.; Husson, D.; Riester, J.L

    1999-06-01

    The ability of HgI{sub 2} powders, used as precursors in mercuric iodide crystal growth, to produce high-quality detectors may be predicted by non-destructive methods like photoluminescence. In fact, it is possible to correlate the presence and the intensity ratio of specific bands in the photoluminescence spectrum of a HgI{sub 2} crystal to its impurity content and stoichiometry. These quantities determine the detector grade that may be achieved using that starting material. Nine different HgI{sub 2} precursors, obtained by different purification methods, have been characterized. The lowest impurity content is achieved via poly-ethylene treatment, which gives also a powder of relatively good stoichiometric quality.

  5. Derivation of multipotent mesenchymal precursors from human embryonic stem cells.

    Directory of Open Access Journals (Sweden)

    2005-06-01

    Full Text Available BACKGROUND: Human embryonic stem cells provide access to the earliest stages of human development and may serve as a source of specialized cells for regenerative medicine. Thus, it becomes crucial to develop protocols for the directed differentiation of embryonic stem cells into tissue-restricted precursors. METHODS AND FINDINGS: Here, we present culture conditions for the derivation of unlimited numbers of pure mesenchymal precursors from human embryonic stem cells and demonstrate multilineage differentiation into fat, cartilage, bone, and skeletal muscle cells. CONCLUSION: Our findings will help to elucidate the mechanism of mesoderm specification during embryonic stem cell differentiation and provide a platform to efficiently generate specialized human mesenchymal cell types for future clinical applications.

  6. Turbulence-induced magnetic fields in shock precursors

    CERN Document Server

    del Valle, Maria Victoria; Santos-Lima, Reinaldo

    2016-01-01

    Galactic cosmic rays are believed to be mostly accelerated at supernova shocks. However, the interstellar magnetic field is too weak to efficiently accelerate galactic cosmic rays up to the highest energies, i.e. $10^{15}$ eV. A stronger magnetic field in the pre-shock region could provide the efficiency required. Bell's cosmic-ray nonresonant streaming instability has been claimed to be responsible for the amplification of precursor magnetic fields. However, an alternative mechanism has been proposed in which the cosmic-ray pressure gradient forms the shock precursor and drives turbulence, amplifying the magnetic field via the small-scale dynamo. A key ingredient for the mechanism to operate are the inhomogeneities present in the interstellar medium (ISM). These inhomogeneities are the consequence of turbulence. In this work we explore the magnetic field amplification in different ISM conditions through 3D MHD numerical simulations.

  7. Optical precursors from classical waves to single photons

    CERN Document Server

    Chen, JF; Loy, MMT; Du, Shengwang

    2013-01-01

    Ever since Einstein’s special relativity in 1905, the principle of invariant light speed in vacuum has been attracting attention from a wide range of disciplines. How to interpret the principle of light speed? Is light referred to continuous light, or light pulse with definite boundaries? Recent discovery of superluminal medium triggered vigorous discussion within the Physics community. Can communication via such “superluminal channel” break the speed limit and thus violate causality principle? Or, will a single photon, which is not governed by classical laws of Physics, tend to break the speed limit? To solve these problems, in this Brief we bring in optical precursor, the theoretical works for which started as early as 1914. This is a typical optical phenomenon combining wave propagation theory and light-wave interaction. Both theory and experimental works are covered in this Brief. The study of precursor verifies that the effective information carried by light pulses can never exceed the speed of lig...

  8. Surface reconstruction precursor to melting in Au309 clusters

    OpenAIRE

    Fuyi Chen; Li, Z. Y.; Roy L. Johnston

    2011-01-01

    The melting of gold cluster is one of essential properties of nanoparticles and revisited to clarify the role played by the surface facets in the melting transition by molecular dynamics simulations. The occurrence of elaborate surface reconstruction is observed using many-body Gupta potential as energetic model for 309-atom (2.6 nm) decahedral, cuboctahedral and icosahedral gold clusters. Our results reveal for the first time a surface reconstruction as precursor to the melting transitions. ...

  9. The miR-10 microRNA precursor family

    DEFF Research Database (Denmark)

    Tehler, Disa; Høyland-Kroghsbo, Nina Molin; Lund, Anders H

    2011-01-01

    The miR-10 microRNA precursor family encodes a group of short non-coding RNAs involved in gene regulation. The miR-10 family is highly conserved and has sparked the interest of many research groups because of the genomic localization in the vicinity of, coexpression with and regulation of the Hox...... gene developmental regulators. Here, we review the current knowledge of the evolution, physiological function and involvement in cancer of this family of microRNAs....

  10. Lineage specification of neuronal precursors in the mouse spinal cord.

    OpenAIRE

    L.J. Richards; Murphy, M.; Dutton, R; Kilpatrick, T J; Puche, A. C.; Key, B; Tan, S S; Talman, P S; Bartlett, P. F.

    1995-01-01

    We have investigated the differentiation potential of precursor cells within the developing spinal cord of mice and have shown that spinal cord cells from embryonic day 10 specifically give rise to neurons when plated onto an astrocytic monolayer, Ast-1. These neurons had the morphology of motor neurons and > 83% expressed the motor neuron markers choline acetyltransferase, peripherin, calcitonin gene-related peptide, and L-14. By comparison, < 10% of the neurons arising on monolayers of othe...

  11. Characterizing the signature of flame flashback precursor through recurrence analysis

    Science.gov (United States)

    Christodoulou, Loizos; Kabiraj, Lipika; Saurabh, Aditya; Karimi, Nader

    2016-01-01

    In this paper, it is shown that prior to flashback, small dynamical changes appear in the system. These changes appear as a drift in the recurrence plots and are found to be associated with a gradual increase in the determinism and recurrence rate. Thus, this study indicates that precursors to flame flashback exist and can be detected in the multidimensional phase space reconstructed from pressure measurements acquired during flashback. This observation could have broad academic as well as industrial implications.

  12. Copper Promotes the Trafficking of the Amyloid Precursor Protein*

    OpenAIRE

    Acevedo, Karla M.; Hung, Ya Hui; Dalziel, Andrew H.; Li, Qiao-Xin; Laughton, Katrina; Wikhe, Krutika; Rembach, Alan; Roberts, Blaine; Masters, Colin L.; Ashley I. Bush; Camakaris, James

    2010-01-01

    Accumulation of the amyloid β peptide in the cortical and hippocampal regions of the brain is a major pathological feature of Alzheimer disease. Amyloid β peptide is generated from the sequential protease cleavage of the amyloid precursor protein (APP). We reported previously that copper increases the level of APP at the cell surface. Here we report that copper, but not iron or zinc, promotes APP trafficking in cultured polarized epithelial cells and neuronal cells. In SH-SY5Y neuronal cells ...

  13. [Plant sterols, cholesterol precursors and oxysterols: small amounts, big effects].

    Science.gov (United States)

    Olkkonen, Vesa M; Gylling, Helena; Ikonen, Elina

    2015-01-01

    Noncholesterol sterols are present in the body in very low concentrations compared with cholesterol. Minor structural changes in sterols give them completely individual biological activities. Steroid hormones are the best known example of this. The knowledge of other relatives of cholesterol, particularly plant sterols, cholesterol precursors and oxysterols, their properties, physiological effects, significance in disease processes and diagnostic applications has recently undergone a rapid increase.

  14. Hemopoietic cell precursor responses to erythropoietin in plasma clot cultures

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, W.L.

    1979-01-01

    The time dependence of the response of mouse bone marrow cells to erythropoietin (Ep) in vitro was studied. Experiments include studies on the Ep response of marrow cells from normal, plethoric, or bled mice. Results with normal marrow reveal: (1) Not all erythroid precursors (CFU-E) are alike in their response to Ep. A significant number of the precursors develop to a mature erythroid colony after very short Ep exposures, but they account for only approx. 13% of the total colonies generated when Ep is active for 48 hrs. If Ep is active more than 6 hrs, a second population of erythroid colonies emerges at a nearly constant rate until the end of the culture. Full erythroid colony production requires prolonged exposure to erythropoietin. (2) The longer erythropoietin is actively present, the larger the number of erythroid colonies that reach 17 cells or more. Two distinct populations of immediate erythroid precursors are also present in marrow from plethoric mice. In these mice, total colony numbers are equal to or below those obtained from normal mice. However, the population of fast-responding CFU-E is consistently decreased to 10 to 20% of that found in normal marrow. The remaining colonies are formed from plethoric marrow at a rate equal to normal marrow. With increasing Ep exposures, the number of large colonies produced increases. From the marrow of bled mice, total erythroid colony production is equal to or above that of normal marrow. Two populations of colony-forming cells are again evident, with the fast-responding CFU-E being below normal levels. The lack of colonies from this group was compensated in bled mice by rapid colony production in the second population. A real increase in numbers of precursors present in this pool increased the rate of colony production in culture to twice that of normal marrow. The number of large colonies obtained from bled mice was again increased as the Ep exposure was lengthened. (ERB)

  15. Effects of endotoxin on proliferation of human hematopoietic cell precursors

    OpenAIRE

    Rinehart, John J.; Keville, Lisa

    1997-01-01

    In examining the effects of corticosteroids on hematopoiesis in vitro, we observed that results were highly dependent on the lot of commercial fetal calf serum (FCS) utilized. We hypothesized that this variability correlated with the picogram (pg) level of endotoxin contaminating the FCS. Randomly obtained commercial lots of FCS contained 0.39 to 187 pg/ml of lipopolysaccharide (LPS). Standard FCS concentrations in hematopoietic precursor proliferation assays (granulocyte-marcrophage colony f...

  16. COS in the stratosphere. [sulfuric acid aerosol precursor

    Science.gov (United States)

    Inn, E. C. Y.; Vedder, J. F.; Tyson, B. J.; Ohara, D.

    1979-01-01

    Carbonyl sulfide (COS) has been detected in the stratosphere, and mixing ratio measurements are reported for altitudes of 15.2 to 31.2 km. A large volume, cryogenic sampling system mounted on board a U-2 aircraft has been used for lower stratosphere measurements and a balloon platform for measurement at 31.2 km. These observations and measurements strongly support the concept that stratospheric COS is an important precursor in the formation of sulfuric acid aerosols.

  17. A Importância dos Carboidratos na Alimentação dos Eqüinos

    Directory of Open Access Journals (Sweden)

    Eliane Morgado:

    2008-10-01

    Full Text Available Os carboidratos são extremamente importantes na dieta dos eqüinos,sendo os carboidratos não estruturais as fontes primárias de energia. Os monossacarídeos são as únicas formas de carboidratos que podem ser absorvidos pelo intestino delgado e os carboidratos mais complexos são fermentados no intestino grosso, onde ocorre a fermentação microbiana. As frações dos carboidratos são definidas pelos métodos químicos ou enzimáticos utilizados nas análises, e vários são os métodos de avaliação da qualidade das forragens, e da composição bromatológica dos ingredientes. O sistema de partição dos carboidratos mais adequada à fisiologia digestiva dos eqüinos, seria o fracionamento dos carboidratos não fibrosos em grupo dos Carboidratos hidrolisáveis a açúcar simples no intestino delgado, e grupo dos carboidratos fermentáveis no intestino grosso, produzindo ácidos graxos voláteis.

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

    Directory of Open Access Journals (Sweden)

    Sílvia Coimbra

    2015-04-01

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

  19. Dos iglesias de Pierre Pinsard, arquitecto Francia

    Directory of Open Access Journals (Sweden)

    Pinsard, Pierre

    1972-09-01

    Full Text Available Parish Centre of Saint Pierre de Chanel, Bourg-en-Bresse It is located in the modern part of the town, and is built on three levels: — Basement, with public garage. — Ground floor, which has nave with seating capacity for 639, chapel, mortuary, sacristy, presbytery and offices, as well as courtyard, garden, car-park and belfry. — Upper floor, with catechism rooms, gallery, offices and sitting rooms annexed to the presbytery. The basic construction is of expossd concrete with metal columns. Parish Centre of Saint Jean Baptiste de La Salle, Rouen This building is situated on the left bank of the Seine. Consisting of one floor only, it has a main nave with room for 600, a chapel, catechism rooms, two sacristies, mortuary, presbytery, choir and gardens. The construction is of concrete faced with brick, and metal roof with interior wood lining.Centro Parroquial de San Pedro de Chanel, en Bourg-en-Bresse Esta situado en la zona moderna y se ha distribuido en tres plantas: — Sótano: con garaje público. — Planta noble: con nave capaz para 639 plazas, capilla, mortuorio, sacristía, presbiterio y oficinas; además de la plaza, el jardin, aparcamiento y campanil. — Planta alta: con salas de catecismo, tribuna, oficinas y estancias anejas al presbiterio. Construcción fundamental de hormigón visto con pilares metálicos. Centro Parroquial de San Juan Bautista de La Salle, en Ruán Está situado en la orilla izquierda del Sena. Consta de una sola planta, con nave para 600 fieles, capilla, salas de catecismo, dos sacristías, mortuorio, presbiterio, coro y jardines. Construcción a base de hormigón, fábrica de ladrillo a cara vista y cubierta metálica revestida de madera el interior.

  20. ESTUDO SOBRE O IMPACTO DOS PROCESSADORES HOSPEDEIROS

    Directory of Open Access Journals (Sweden)

    Alba S. B. Lopes

    2008-05-01

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

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

    OpenAIRE

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

    2011-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Retamal González Antonio

    2000-01-01

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

  3. A linguagem dos filmes norte-americanos ao longo dos anos: uma abordagem multidimensional

    OpenAIRE

    Pinto, Marcia Veirano

    2013-01-01

    O objetivo desta pesquisa é investigar dimensões de variação na linguagem dos filmes americanos ao longo de 80 anos de cinema falado. Para tanto, buscou-se suporte teórico na visão de linguagem da Linguística de Corpus e na abordagem metodológica da Análise Multidimensional. Mais especificamente, nas duas modalidades propostas por essa metodologia: a que mapeia o registro filme nas 5 dimensões de variação do inglês apontadas por Biber (1988), e a que propõe novas dimensões de...

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

    Directory of Open Access Journals (Sweden)

    Edelmira Ochoa Camacho

    2015-12-01

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

  5. Laser-induced metal reduction from liquid electrolyte precursor.

    Science.gov (United States)

    Kim, Dongsoo; Choi, Choljin

    2013-11-01

    A special sort of laser methods such as direct writing of metal and thin film deposition from liquid precursors was developed for the surface processing and the localized metallization of different kinds of materials. Laser radiation initiates the chemical reaction resulted in the reduction of the metal complexes to the metals in the liquid electrolyte, followed by the metal deposition on the substrate with a high degree of the adhesion. In this study, continuous wave of Ar+ laser generated in multiwave regime with laser power from 5 to 500 mW was chosen for the Copper reduction and deposition on SiO2 substrate. In order to investigate the effect of salt precursors on the properties of the deposited structures, two kinds of electrolyte solution were prepared on the base of CuSO4 and CuCl2. It was shown that metal deposition can be initiated at the laser power of 50 mW. The width of the deposits was found to be substantially dependent on the applied laser power. Deposits were revealed as conductive layers and the resistance of the layers depends strongly on the solution temperature and the salt precursor.

  6. Structural analysis of the precursor pseudogap in cuprate superconductors

    Science.gov (United States)

    Suzuki, Sokichi

    2016-10-01

    We investigate the precursor pseudogap (PP) state that emerges on the lower temperature side of the pseudogap phase in cuprate superconductors based on the characteristic layer structure. The coherence among layers in the electronic state may be broken by low energy thermal interactions, whereas the coherence within the layers remains in the phase above the superconducting (SC) phase on account of strongness of the bonding. In this state, the two-electron energy gain (TEG) is also larger than that of SC state and the one-electron energy gain (OEG) is smaller than that of the SC state. We call this incoherent ensemble of in-layer states the in-layer electronic state system (IESS). The PP state is a crossover state between IESS and the normal pseudogap (NP) state, which appears on the upper temperature side, because the d-wave pairing symmetry in cuprates inverts the sign of the difference of the total electronic energy gain between the IESS and the NP state around the nodal region, even though it is positive overall. We perform our analysis at the mean field level. We show that the relationships among the SC gap, the gap of in-layer state, and the transition temperatures in the relevant phases are compatible with existing experimental data. The proposed precursor state requires pairing models to make the SC interactions three-dimensional beyond a single layer, although the precursors have in-layer properties.

  7. Development of techniques for tagging precursor and essential chemicals

    Energy Technology Data Exchange (ETDEWEB)

    Swansiger, W.A.; Shepodd, T.J. [Sandia National Labs., Livermore, CA (United States); Phillips, M.L.F. [Sandia National Labs., Albuquerque, NM (United States)

    1994-01-01

    The ability to identify the manufacturers and distributors of chemicals seized in raids of illicit drug labs would be of great value in controlling the diversion of these chemicals. We developed a tagging scheme based on the addition of sub-ppM concentrations of various combinations of rare-earth elements to the target chemicals and evaluated a number of techniques for detecting the tags. We developed soluble tags for tagging liquids and selected Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) as the preferred detection technique. We developed insoluble tags for tagging solids and developed methods to analyze them and mix them into solid precursors. We have successfully demonstrated the tagging of several solvents and two of the precursor chemicals used in one of the most popular clandestine methamphetamine syntheses (ephedrine reacting with hydriodic acid/red phosphorus). The tagging scheme is capable of yielding tens of thousands of signatures (using holmium as an internal standard and up to 9 rare-earths at up to 3 concentrations yields 3{sup 9} {minus} 1 = 19,682 signatures) and is applicable to most of the chemicals on the precursor and essential chemicals list. In the concentrations employed, the tags are safe enough to be added to pharmaceuticals and cheap enough to tag tanker loads of chemicals.

  8. Reduction of precursor decay anomaly in single crystal lithium fluoride

    Science.gov (United States)

    Sano, Yukio

    2000-08-01

    The purpose of this study is to reveal that the precursor decay anomaly in single crystal lithium fluoride is reduced by Sano's decay curve [Y. Sano, J. Appl. Phys. 85, 7616 (1999)], which is much smaller in slope than Asay's decay curve [J. R. Asay, G. R. Fowles, G. E. Duvall, M. H. Miles, and R. F. Tinder, J. Appl. Phys. 43, 2132 (1972)]. To this end, strain, particle, velocity, and stress in a precursor and near the leading edge of the follower changing with time along Sano's decay curve are first analyzed quantitatively. The analysis verified the existence of degenerate contraction waves I and II and a subrarefaction wave R', and the decay process [Y. Sano, J. Appl. Phys. 77, 3746 (1995)] caused in sequence by evolving followers C, I, II, R', Rb. Next, inequalities relating decay rates qualitatively to plastic strain rates at the leading edge of the follower, which are derived using the properties of the followers, are incorporated into the analysis. Calculation results showed that the plastic strain rates were reduced by low decay rates. This indicates that the precursor decay anomaly might be greatly reduced by Sano's decay curve.

  9. Spectroscopy Study of Synthetic Forsterite Obtained from Zeolite Precursors

    Directory of Open Access Journals (Sweden)

    Subotić, B.

    2008-02-01

    Full Text Available Important ceramics materials are prepared from aluminosilicate based precursors using novel methods, offering at the same time a better control over many important properties. Forsterite, due to its good refractoriness with melting point at 2163 K, excellent electrical insulation properties even at high temperatures, low dielectric permittivity, thermal expansion and chemical stability, is a material of interest to engineers and designers especially as an active medium for tuneable laser and is also a material of interest to SOFC (Solid oxide fuel cells manufacturers. The aim of this study is to investigate the synthesis of crystalline forsterite using different zeolite precursors previously activated by ball milling. Synthetic forsterite was synthesized from different zeolite precursors and MgO combining highenergy ball milling and thermal treatment of the mixture under determined conditions of time and temperature for each operation. In this research are studied the solid-state phase transformations taking place at temperatures below 1273 K. The obtained products were characterized using different spectroscopy techniques in comparison with surface analysis method and X-ray diffraction.

  10. Elastic Precursor Decay in S-200F Beryllium

    Science.gov (United States)

    Adams, Chris; Anderson, William; Blumenthal, William; Gray, George (Rusty), III

    2013-06-01

    We have performed a number of plate impact experiments on vacuum hot-pressed (VHP) S-200F Be at shock stresses between 2.1 and 23 GPa to gain insight into the dynamic strength and damage behavior of this technologically important material. In this discussion we will focus on our observations of dynamic strength represented by the Hugoniot Elastic Limit (HEL) determined from the amplitude of the elastic precursor wave observed in VISAR wave profiles collected at the rear surface of the target for experiments conducted in transmission geometry. We observe monotonic decay in precursor amplitude with run distance for sample thicknesses between 4 and 8 mm. We will discuss the observed precursor decay with respect to the relative roles of twinning and dislocation mediated slip in the overall material mechanical response. We will make comparisons with similar data obtained from experiments conducted on roll-textured plate where the contribution of twinning to initial deformation is expected to be suppressed. C. D. Adams et al., ``Shock Compression of Condensed Matter - 2009,'' AIP Conference Proceedings 1195, 1, 509-512 (2009).

  11. Precursor lesions in pancreatic cancer: morphological and molecular pathology.

    Science.gov (United States)

    Scarlett, Christopher J; Salisbury, Elizabeth L; Biankin, Andrew V; Kench, James

    2011-04-01

    Pancreatic cancer has a dismal prognosis and is the fourth most common cause of cancer related death in Western societies. In large part this is due to its typically late presentation, usually as locally advanced or metastatic disease. Identification of the non-invasive precursor lesions to pancreatic cancer raises the possibility of surgical treatment or chemoprevention at an early stage in the evolution of this disease, when more amenable to therapeutic interventions. Precursor lesions to pancreatic ductal adenocarcinoma, in particular pancreatic intraepithelial neoplasia (PanIN), have been recognised under a variety of synonyms for over 50 years. Over the past decade our understanding of the morphology, biological significance and molecular aberrations of these lesions has grown rapidly and there is now a widely accepted progression model integrating the accumulated morphological and molecular observations. Further progress is likely to be accelerated by improved mouse models of pancreatic cancer and by insight into the cancer genome gained by the International Cancer Genome Consortium (ICGC), in which an Australian consortium is leading the pancreatic cancer initiative. This review also outlines the morphological and molecular features of the other two precursors of pancreatic ductal adenocarcinoma, i.e., intraductal papillary mucinous neoplasms and mucinous cystic neoplasms.

  12. Observations of Electromagnetic Whistler Precursors at Supercritical Interplanetary Shocks

    Science.gov (United States)

    Wilson, L. B., III; Koval, A.; Szabo, Adam; Breneman, A.; Cattell, C. A.; Goetz, K.; Kellogg, P. J.; Kersten, K.; Kasper, J. C.; Maruca, B. A.; Pulupa, M.

    2012-01-01

    We present observations of electromagnetic precursor waves, identified as whistler mode waves, at supercritical interplanetary shocks using the Wind search coil magnetometer. The precursors propagate obliquely with respect to the local magnetic field, shock normal vector, solar wind velocity, and they are not phase standing structures. All are right-hand polarized with respect to the magnetic field (spacecraft frame), and all but one are right-hand polarized with respect to the shock normal vector in the normal incidence frame. They have rest frame frequencies f(sub ci) < f much < f(sub ce) and wave numbers 0.02 approx < k rho (sub ce) approx <. 5.0. Particle distributions show signatures of specularly reflected gyrating ions, which may be a source of free energy for the observed modes. In one event, we simultaneously observe perpendicular ion heating and parallel electron acceleration, consistent with wave heating/acceleration due to these waves. Al though the precursors can have delta B/B(sub o) as large as 2, fluxgate magnetometer measurements show relatively laminar shock transitions in three of the four events.

  13. Prolactin stimulates precursor cells in the adult mouse hippocampus.

    Directory of Open Access Journals (Sweden)

    Tara L Walker

    Full Text Available In the search for ways to combat degenerative neurological disorders, neurogenesis-stimulating factors are proving to be a promising area of research. In this study, we show that the hormonal factor prolactin (PRL can activate a pool of latent precursor cells in the adult mouse hippocampus. Using an in vitro neurosphere assay, we found that the addition of exogenous PRL to primary adult hippocampal cells resulted in an approximate 50% increase in neurosphere number. In addition, direct infusion of PRL into the adult dentate gyrus also resulted in a significant increase in neurosphere number. Together these data indicate that exogenous PRL can increase hippocampal precursor numbers both in vitro and in vivo. Conversely, PRL null mice showed a significant reduction (approximately 80% in the number of hippocampal-derived neurospheres. Interestingly, no deficit in precursor proliferation was observed in vivo, indicating that in this situation other niche factors can compensate for a loss in PRL. The PRL loss resulted in learning and memory deficits in the PRL null mice, as indicated by significant deficits in the standard behavioral tests requiring input from the hippocampus. This behavioral deficit was rescued by direct infusion of recombinant PRL into the hippocampus, indicating that a lack of PRL in the adult mouse hippocampus can be correlated with impaired learning and memory.

  14. Prospective use of skin-derived precursors in neural regeneration

    Institute of Scientific and Technical Information of China (English)

    LU Xiao-cheng; TAO Yi; LI Li-xin

    2012-01-01

    Objective To review recent studies concerning the origins of skin-derived precursors (SKPs),their differentiation characteristics,and their potential application in neural regenerative medicine.Data sources Data were retrieved from studies reported in PubMed published between April,1974 and June,2012.The search terms used were "skin-derived precursors","stem cells",and "neural diseases".Study selection Articles were included in the review if they were relevant to SKPs as stem cells,as well as their applications in neural regenerative medicine,such as in the treatment of spinal cord injury,Parkinson's disease,spinal muscular atrophy and Shah-Waardenburg syndrome.Results SKPs are a novel population of neural crest-derived precursors that arise during embryogenesis and persist into adulthood.They can generate both neural cells and mesodermal lineage cells (including smooth muscle cells and adipocytes).Compared with other stem cells,SKPs are abundant in adult skin,can differentiate easily into neural cells,and are not associated with any ethical controversies.Conclusion SKPs may provide an alternative source of stem cells to embryonic stem cells for transplantation therapy for neurological diseases.

  15. Thermogravimetric evaluation of the suitability of precursors for MOCVD

    Science.gov (United States)

    Kunte, G. V.; Shivashankar, S. A.; Umarji, A. M.

    2008-02-01

    A method based on the Langmuir equation for the estimation of vapour pressure and enthalpy of sublimation of subliming compounds is described. The variable temperature thermogravimetric/differential thermogravimetric (TG/DTG) curve of benzoic acid is used to arrive at the instrument parameters. Employing these parameters, the vapour pressure-temperature curves are derived for salicylic acid and camphor from their TG/DTG curves. The values match well with vapour pressure data in the literature, obtained by effusion methods. By employing the Clausius-Clapeyron equation, the enthalpy of sublimation could be calculated. Extending the method further, two precursors for metal-organic chemical vapour deposition (MOCVD) of titanium oxide bis-isopropyl bis tert-butyl 2-oxobutanoato titanium, Ti(OiPr)2(tbob)2, and bis-oxo-bis-tertbutyl 2-oxobutanoato titanium, [TiO(tbob)2]2, have been evaluated. The complex Ti(OiPr)2(tbob)2 is found to be a more suitable precursor. This approach can be helpful in quickly screening for the suitability of a compound as a CVD precursor.

  16. Precursors in the preparation of transition metal nitrides and transition metal carbonitrides and their reaction intermediates

    Science.gov (United States)

    Maya, Leon

    1991-01-01

    A process for making ammonolytic precursors to nitride and carbonitride ceramics. Extreme reaction conditions are not required and the precursor is a powder-like substance that produces ceramics of improved purity and morphology upon pyrolysis.

  17. Evidence for a Direct Effect of the NAD+ Precursor Acipimox on Muscle Mitochondrial Function in Humans

    NARCIS (Netherlands)

    van de Weijer, T.; Phielix, E.; Bilet, L.; Williams, E.G.; Ropelle, E.R.; Bierwagen, A.; Livingstone, R.; Nowotny, P.; Sparks, L.M.; Paglialunga, S.A.; Szendroedi, J.; Havekes, B.; Moullan, N.; Pirinen, E.; Hwang, J.H.; Schrauwen-Hinderling, V.B.; Hesselink, M.K.; Auwerx, J.; Roden, M.; Schrauwen, P.

    2015-01-01

    Recent preclinical studies showed the potential of nicotinamide adenine dinucleotide : NAD+ : precursors to increase oxidative phosphorylation and improve metabolic health, but human data is lacking. Here, we hypothesized that the nicotinic acid derivative Acipimox, a NAD+ precursor, would directly

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

    Directory of Open Access Journals (Sweden)

    Weber Soares

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

  19. Resist DoS attacks in UMTS-WLAN

    Science.gov (United States)

    Qu, Huyu; Cheng, Qiang

    2005-06-01

    Wireless network is more vulnerable to denial of service (DoS) attacks than wired one. In this paper we propose two methods to resist DoS attacks in UMTS-WLAN network, one is active and the other is passive. These two are complementary to each other. In active DoS defense method, a mobile terminal generates an authorized anonymous ID (AAI) using its true ID such as IP address, MAC address, PIN code, or asymmetric key, and substitutes its true ID with the authorized anonymous ID. The mobile terminal may be authenticated by the UMTS-WLAN, however its true ID is anonymous to intending attackers. This method can be used to isolate de-authenticating/disassociating DoS attackers, spoofing power-save DoS attacker, etc. In passive DoS defense method, we propose a trace back scheme. We use covert channels in the header of mobile IP packets to trace back the malicious nodes by embedding some address information of intermediate nodes, and recovering the embedded information by the victim. After the victim successfully traces the attacking paths from malicious nodes, it can segregate the malicious nodes and protect itself. This method can be used to resist DoS attacks of mass-produced junk message congestions.

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

    Directory of Open Access Journals (Sweden)

    Townsend Ludington

    2008-04-01

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

  1. A institucionalização da câmara dos deputados dos Estados Unidos

    Directory of Open Access Journals (Sweden)

    Nelson W. Polsby

    2008-06-01

    Full Text Available O artigo analisa como se deu a institucionalização da Câmara dos Deputados dos Estados Unidos, desde seu início, no final do século XVIII, até meados do século XX. Esse processo é analisado a partir de três variáveis fundamentais: 1 a delimitação funcional em relação a outras organizações, particularmente políticas; 2 a relativa complexidade da instituição, ou seja, até que ponto suas funções são internamente separadas em alguma base regular e explícita; 3 o universalismo e o automatismo nos procedimentos adotados para conduzir seus diversos assuntos internos. Cada uma dessas variáveis é sucessivamente examinada do ponto de vista histórico ao longo do artigo; a título de conclusão, apresentam-se algumas observações especulativas sobre causas, conseqüências e possíveis lições que se pode tirar da institucionalização da Câmara.

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

    Directory of Open Access Journals (Sweden)

    Fernando de Holanda Barbosa

    2005-06-01

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

  3. Escravidão, Biografias e a Memória dos Excluídos

    Directory of Open Access Journals (Sweden)

    Nielson Rosa Bezerra

    2011-08-01

    Full Text Available A biografia foi restituída como um tipo de abordagem voltada para a explicação das experiências coletivas através da perseguição de singularidades capazes de expressar o indivíduo como uma representação da sociedade e do contexto onde ele viveu. Essa perseguição poderia ser percebida através da noção de como tratar as fontes históricas considerando os indícios e pistas que, mesmo com uma perspectiva indireta, acabam por oferecer especificidades sobre as pessoas. Assim, eu gostaria de oferecer uma crítica reflexiva considerando as potencialidades da abordagem biográfica no campo de estudos da escravidão africana como uma breve contribuição para se pensar a memória dos excluídos no mundo moderno.

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

    Directory of Open Access Journals (Sweden)

    Andrea Pacheco Pacífico

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

  5. Amyloid Precursor Protein Processing in Alzheimer’s Disease

    Directory of Open Access Journals (Sweden)

    Adwait BHADBHADE

    2012-03-01

    Full Text Available How to Cite this Article: Bhadbhade A, Cheng DW. Amyloid Precursor Protein Processing in Alzheimer’s Disease. Iranian Journal of Child Neurology2012;6(1:1-5.Alzheimer’s disease (AD is a progressive neurodegenerative disorder and a leading cause of dementia. The AD is characterized by presence of intraneuronal tangles and extracellular plaques in the brain. The plaques are composed of dense and mostly insoluble deposits of amyloid beta peptide (Aβ, formed by sequential cleavage of the Amyloid Precursor Protein (APP, by two pathways amyloidogenic and non-amyloidogenic. Tangles are composed of paired helical fragments, which aggregate to form, microtubular protein tau. Although Aβ plaques are established to be the cause of the disease, there exist genetic factors and other pathological identifications in addition to these which are an integral part of the disease. This article gives an overview into the mechanism of APP action, genetic factors and other pathological identifications contributing to Alzheimer’s disease formation.References Brookmeyer R, Gray S, Kawas C. Projections of Alzheimer’s disease in the United States and the public health impact of delaying disease onset. American Journal of Public Health 1998;88(9:1337. Hebert LE, Scherr PA, Bienias JL, Bennett DA, Evans DA. Alzheimer disease in the US population. Arch Neurol 2003;60(8:1119-22. Möller HJ, Graeber M. The case described by Alois Alzheimer in 1911. European Archives of Psychiatry and Clinical Neuroscience 1998:248(3:111-122. Selkoe D J. (2002. Deciphering the genesis and fate of amyloid beta-protein yields novel therapies for Alzheimer disease. J Clinic Investigat 2002;110(10: 1375-82. Wolfe MS. Tau mutations in neurodegenerative diseases. J Biolog Chem 2009;284(10:6021. Selkoe DJ. Alzheimer’s disease: genes, proteins, and therapy. Physiological reviews 2001;81(2:741. Selkoe DJ. The cell biology of [beta]-amyloid precursor protein and presenilin in Alzheimer

  6. Pig epidermal growth factor precursor contains segments that are highly conserved among species

    DEFF Research Database (Denmark)

    Jørgensen, P E; Jensen, L.G.; Sørensen, B S

    1998-01-01

    The 53-aa polypeptide epidermal growth factor (EGF) is synthesized as a 1200-aa precursor. The non-EGF part of the precursor is very long compared with EGF, and can therefore be expected to have a biological role of its own. We have sequenced cDNA of the pig EGF precursor and compared a 668-aa se...

  7. Production of a Mouse Antiserum to Bacteroides fragilis Enterotoxin Using a Recombinant Enterotoxin Precursor

    OpenAIRE

    Sandini, Silvia; d'Abusco, Anna Scotto; La Valle, Roberto; Pantosti, Annalisa

    2001-01-01

    The precursor of the Bacteroides fragilis metalloprotease enterotoxin was cloned and expressed in Escherichia coli, which was not able to process the precursor into the biologically active enterotoxin. Mouse antiserum elicited to the recombinant precursor reacted with the purified enterotoxin and with a crude enterotoxin preparation from an enterotoxigenic strain. The antiserum neutralized the cytotoxic activity of the enterotoxin in HT-29 cells.

  8. Liquid precursor for deposition of indium selenide and method of preparing the same

    Energy Technology Data Exchange (ETDEWEB)

    Curtis, Calvin J.; Miedaner, Alexander; van Hest, Marinus Franciscus Antonius Maria; Ginley, David S.; Hersh, Peter A.; Eldada, Louay; Stanbery, Billy J.

    2015-09-22

    Liquid precursors containing indium and selenium suitable for deposition on a substrate to form thin films suitable for semiconductor applications are disclosed. Methods of preparing such liquid precursors and method of depositing a liquid precursor on a substrate are also disclosed.

  9. Dos traducciones costarricenses de Guy de Maupassant

    Directory of Open Access Journals (Sweden)

    Alejandro Alvarado Quirós

    2016-09-01

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

  10. Uma análise da teoria dos arquivos

    OpenAIRE

    Ana Marcia Lutterbach Rodrigues

    2004-01-01

    Estudo da teoria dos arquivos, baseado em sua literatura, com o objetivo de identificação dos fundamentos da arquivologia e de encontrar neste campo de estudo a possibilidade de maior cientificidade nos seus desenvolvimentos. O estudo é feito através da análise comparativa dos principais conceitos conforme enunciados pelos autores da área. Destacam-se as noções que se mostram como indispensáveis para a definição de arquivo e apresenta-se uma formulação para o conceito, procurando incorporar t...

  11. Sobriedade e embriaguez: a luta dos soldados de Cristo contra as festas dos tupinambás

    Directory of Open Access Journals (Sweden)

    João Azevedo Fernandes

    2007-01-01

    Full Text Available O artigo analisa a luta dos missionários cristãos, em especial os jesuítas, contra as festas e as bebidas alcoólicas dos tupinambás. Eles perceberam que, nestas festas, a cultura tupinambá, principal obstáculo à evangelização, se renovava e se reafirmava constantemente. O artigo também explora as principais estratégias usadas pelos europeus para alcançar o objetivo de extinguir as festas dos índios.

  12. Tecnologia dos sonhos em Artemidoro, Freud, Jung e nos Warlpiri

    Directory of Open Access Journals (Sweden)

    Abrahão de Oliveira Santos

    2014-08-01

    Full Text Available Apresentaremos distintas tecnologias dos sonhos: em Artemidoro, Freud, Jung e nos Warlpiri. Artemidoro revela a mensagem onírica imprescindível à condução do cidadão, com os elementos das instituições, da cidade, do cosmo. Com Freud, no moderno mundo europeu, o sonho recebe o sentido da interioridade. Outra leitura é de Carl Jung. O uso dos sonhos tem seu sentido histórico, se relacionando com as práticas de governo, os modos de condução da vida e da cidade. Para além das tradições eurodescendentes e mentalistas vigentes, apresentaremos a tecnologia coletiva dos sonhos dos Warlpiri e uma nova possibilidade de lidarmos com a experiência onírica.

  13. Cloning, expression and processing of the CP2 neuropeptide precursor of Aplysia.

    Science.gov (United States)

    Vilim, F S; Alexeeva, V; Moroz, L L; Li, L; Moroz, T P; Sweedler, J V; Weiss, K R

    2001-12-01

    The cDNA sequence encoding the CP2 neuropeptide precursor is identified and encodes a single copy of the neuropeptide that is flanked by appropriate processing sites. The distribution of the CP2 precursor mRNA is described and matches the CP2-like immunoreactivity described previously. Single cell RT-PCR independently confirms the presence of CP2 precursor mRNA in selected neurons. MALDI-TOF MS is used to identify additional peptides derived from the CP2 precursor in neuronal somata and nerves, suggesting that the CP2 precursor may give rise to additional bioactive neuropeptides.

  14. Accident Precursor Analysis and Management: Reducing Technological Risk Through Diligence

    Science.gov (United States)

    Phimister, James R. (Editor); Bier, Vicki M. (Editor); Kunreuther, Howard C. (Editor)

    2004-01-01

    Almost every year there is at least one technological disaster that highlights the challenge of managing technological risk. On February 1, 2003, the space shuttle Columbia and her crew were lost during reentry into the atmosphere. In the summer of 2003, there was a blackout that left millions of people in the northeast United States without electricity. Forensic analyses, congressional hearings, investigations by scientific boards and panels, and journalistic and academic research have yielded a wealth of information about the events that led up to each disaster, and questions have arisen. Why were the events that led to the accident not recognized as harbingers? Why were risk-reducing steps not taken? This line of questioning is based on the assumption that signals before an accident can and should be recognized. To examine the validity of this assumption, the National Academy of Engineering (NAE) undertook the Accident Precursors Project in February 2003. The project was overseen by a committee of experts from the safety and risk-sciences communities. Rather than examining a single accident or incident, the committee decided to investigate how different organizations anticipate and assess the likelihood of accidents from accident precursors. The project culminated in a workshop held in Washington, D.C., in July 2003. This report includes the papers presented at the workshop, as well as findings and recommendations based on the workshop results and committee discussions. The papers describe precursor strategies in aviation, the chemical industry, health care, nuclear power and security operations. In addition to current practices, they also address some areas for future research.

  15. Glutamine: precursor or nitrogen donor for citrulline synthesis?

    Science.gov (United States)

    Marini, Juan C; Didelija, Inka Cajo; Castillo, Leticia; Lee, Brendan

    2010-07-01

    Although glutamine is considered the main precursor for citrulline synthesis, the current literature does not differentiate between the contribution of glutamine carbon skeleton vs. nonspecific nitrogen (i.e., ammonia) and carbon derived from glutamine oxidation. To elucidate the role of glutamine and nonspecific nitrogen in the synthesis of citrulline, l-[2-(15)N]- and l-[5-(15)N]glutamine and (15)N-ammonium acetate were infused intragastrically in mice. The amino group of glutamine labeled the three nitrogen groups of citrulline almost equally. The amido group and ammonium acetate labeled the ureido and amino groups of citrulline, but not the delta-nitrogen. D(5)-glutamine also infused in this arm of the study, which traces the carbon skeleton of glutamine, was utilized poorly, accounting for only 0.2-0.4% of the circulating citrulline. Dietary glutamine nitrogen (both N groups) incorporation was 25-fold higher than the incorporation of its carbon skeleton into citrulline. To investigate the relative contributions of the carbon skeleton and nonspecific carbon of glutamine, arginine, and proline to citrulline synthesis, U-(13)C(n) tracers of these amino acids were infused intragastrically. Dietary arginine was the main precursor for citrulline synthesis, accounting for approximately 40% of the circulating citrulline. Proline contribution was minor (3.4%), and glutamine was negligible (0.4%). However, the glutamine tracer resulted in a higher enrichment in the ureido group, indicating incorporation of nonspecific carbon from glutamine oxidation into carbamylphosphate used for citrulline synthesis. In conclusion, dietary glutamine is a poor carbon skeleton precursor for the synthesis of citrulline, although it contributes both nonspecific nitrogen and carbon to citrulline synthesis.

  16. Molecular analysis of precursor lesions in familial pancreatic cancer.

    Directory of Open Access Journals (Sweden)

    Tatjana Crnogorac-Jurcevic

    Full Text Available BACKGROUND: With less than a 5% survival rate pancreatic adenocarcinoma (PDAC is almost uniformly lethal. In order to make a significant impact on survival of patients with this malignancy, it is necessary to diagnose the disease early, when curative surgery is still possible. Detailed knowledge of the natural history of the disease and molecular events leading to its progression is therefore critical. METHODS AND FINDINGS: We have analysed the precursor lesions, PanINs, from prophylactic pancreatectomy specimens of patients from four different kindreds with high risk of familial pancreatic cancer who were treated for histologically proven PanIN-2/3. Thus, the material was procured before pancreatic cancer has developed, rather than from PanINs in a tissue field that already contains cancer. Genome-wide transcriptional profiling using such unique specimens was performed. Bulk frozen sections displaying the most extensive but not microdissected PanIN-2/3 lesions were used in order to obtain the holistic view of both the precursor lesions and their microenvironment. A panel of 76 commonly dysregulated genes that underlie neoplastic progression from normal pancreas to PanINs and PDAC were identified. In addition to shared genes some differences between the PanINs of individual families as well as between the PanINs and PDACs were also seen. This was particularly pronounced in the stromal and immune responses. CONCLUSIONS: Our comprehensive analysis of precursor lesions without the invasive component provides the definitive molecular proof that PanIN lesions beget cancer from a molecular standpoint. We demonstrate the need for accumulation of transcriptomic changes during the progression of PanIN to PDAC, both in the epithelium and in the surrounding stroma. An identified 76-gene signature of PDAC progression presents a rich candidate pool for the development of early diagnostic and/or surveillance markers as well as potential novel preventive

  17. Precursor times of abnormal b-values prior to mainshocks

    Science.gov (United States)

    Wang, Jeen-Hwa; Chen, Kou-Cheng; Leu, Peih-Lin; Chang, Chien-Hsin

    2016-07-01

    Seismic observations exhibit the presence of abnormal b-values prior to numerous earthquakes. The time interval from the appearance of abnormal b-values to the occurrence of mainshock is called the precursor time. There are two kinds of precursor times in use: the first one denoted by T is the time interval from the moment when the b-value starts to increase from the normal one to the abnormal one to the occurrence time of the forthcoming mainshock, and the second one denoted by T p is the time interval from the moment when the abnormal b-value reaches the peak one to the occurrence time of the forthcoming mainshock. Let T* be the waiting time from the moment when the abnormal b-value returned to the normal one to the occurrence time of the forthcoming mainshock. The precursor time, T (usually in days), has been found to be related to the magnitude, M, of the mainshock expected in a linear form as log( T) = q + rM where q and r are the coefficient and slope, respectively. In this study, the values of T, T p , and T* of 45 earthquakes with 3 ≤ M ≤ 9 occurred in various tectonic regions are compiled from or measured from the temporal variations in b-values given in numerous source materials. The relationships of T and T p , respectively, versus M are inferred from compiled data. The difference between the values of T and T p decreases with increasing M. In addition, the plots of T*/ T versus M, T* versus T, and T* versus T- T* will be made and related equations between two quantities will be inferred from given data.

  18. Educação do campo: demanda dos trabalhadores

    OpenAIRE

    Vania Cristina Pauluk de Jesus

    2006-01-01

    Neste texto pretendemos discutir que especificidades precisa possuir a escola do campo neste mundo neoliberal, identificar as demandas educacionais dos sujeitos do campo e analisar as propostas para educação do campo dos movimentos sociais e Estado. Esta pesquisa é de abordagem qualitativa e, utilizamos como principais instrumentos de coleta de dados a análise documental e entrevistas estruturadas abertas. Para atingir nossos objetivos caracterizamos e discutimos a proposta edu...

  19. Escavando e recordando Olavo Bilac: resgate de textos esquecidos nas páginas dos periódicos

    Directory of Open Access Journals (Sweden)

    Marta Eymael Garcia Scherer

    2010-12-01

    Full Text Available Apresentar os jornais e revistas em que o jornalista Olavo Bilac publicava seus textos é objetivo central deste artigo, que valoriza a recuperação de dezenas de crônicas publicadas entre 1890 e 1908 por aquele que ficou conhecido somente como o ‘príncipe dos poetas. Os textos, recolhidos na Biblioteca Nacional e no Arquivo Edgard Leuenroth, da Unicamp, demonstram a importância de Bilac como precursor de idéias e debates que perpassaram todo século XX e continuam atuais. É assim que peço ‘licença’ ao poeta parnasiano para mostrar o jornalista Olavo Bilac e sua importância dentro da história da literatura e da imprensa nacional.

  20. Escavando e recordando Olavo Bilac: resgate de textos esquecidos nas páginas dos periódicos

    Directory of Open Access Journals (Sweden)

    Marta Eymael Garcia Scherer

    2010-05-01

    Full Text Available http://dx.doi.org/10.5007/1984-784X.2010v10n15p74 Apresentar os jornais e revistas em que o jornalista Olavo Bilac publicava seus textos é objetivo central deste artigo, que valoriza a recuperação de dezenas de crônicas publicadas entre 1890 e 1908 por aquele que ficou conhecido somente como o ‘príncipe dos poetas. Os textos, recolhidos na Biblioteca Nacional e no Arquivo Edgard Leuenroth, da Unicamp, demonstram a importância de Bilac como precursor de idéias e debates que perpassaram todo século XX e continuam atuais. É assim que peço ‘licença’ ao poeta parnasiano para mostrar o jornalista Olavo Bilac e sua importância dentro da história da literatura e da imprensa nacional.

  1. SEGUNDA TELA: A INTERNET PERVASIVA COMO POSSIBILIDADE DE EXTENSÃO DOS CONTEÚDOS TELEVISUAIS

    Directory of Open Access Journals (Sweden)

    Adriana Pierre Coca

    2013-12-01

    Full Text Available Este artigo se alicerça, sobretudo, no conceito do fenômeno segunda tela (PROULX; SHEPATIN, 2012. Analisamos como as emissoras de TV aberta brasileiras vêm se comportando na interação com o ciberespaço. Partimos do pressuposto que, na reconfiguração dos modos de ver televisão; a internet, por ser cada vez mais um meio pervasivo, se torna uma aliada e não um perigo a hegemonia televisual. A transmidiação como apontada por Henry Jenkins (2009 está sendo colocada em prática com entusiasmo e as redes sociais, por exemplo, já se convertem em índices que mostram o reflexo do intenso diálogo entre a TV e a internet.

  2. Efeito dos antimicrobianos sobre a eficácia dos contraceptivos orais

    Directory of Open Access Journals (Sweden)

    CORRÊA Elisabete Míriam de Carvalho

    1998-01-01

    Full Text Available O uso dos antimicrobianos para a profilaxia e tratamento de infecções orais é uma prática comum em odontologia. Sendo assim, é importante que o dentista conheça os riscos potenciais de seu uso, como reações adversas e interações medicamentosas. Uma importante interação envolve o uso concomitante de antimicrobianos e contraceptivos orais, podendo resultar em perda da eficácia contraceptiva e gravidez inesperada. Este artigo faz uma revisão sobre os principais antimicrobianos e possíveis mecanismos envolvidos no processo, assim como analisa a responsabilidade do dentista e os meios de se prevenir tal complicação.

  3. Transient precursor strategy in mineral formation of bone.

    Science.gov (United States)

    Weiner, Steve

    2006-09-01

    The strategy in biomineralization of initially depositing a less ordered mineral and then transforming it into a more crystalline mature phase is probably widespread among invertebrates. The report in this issue by N.J. Crane, V. Popescu, M.D. Morris, P. Steenhuis, M.A. Ignelzi, Raman spectroscopic evidence for octacalcium phosphate and other mineral species deposited during intramembraneous mineralization. Bone (In press), using micro-Raman spectroscopy to study early mineral deposits in mice calvaria, provides strong evidence that the transient precursor strategy also occurs in vertebrates.

  4. Superhydrophobic Ceramic Coatings by Solution Precursor Plasma Spray

    Science.gov (United States)

    Cai, Yuxuan; Coyle, Thomas W.; Azimi, Gisele; Mostaghimi, Javad

    2016-04-01

    This work presents a novel coating technique to manufacture ceramic superhydrophobic coatings rapidly and economically. A rare earth oxide (REO) was selected as the coating material due to its hydrophobic nature, chemical inertness, high temperature stability, and good mechanical properties, and deposited on stainless steel substrates by solution precursor plasma spray (SPPS). The effects of various spraying conditions including standoff distance, torch power, number of torch passes, types of solvent and plasma velocity were investigated. The as-sprayed coating demonstrated a hierarchically structured surface topography, which closely resembles superhydrophobic surfaces found in nature. The water contact angle on the SPPS superhydrophobic coating was up to 65% higher than on smooth REO surfaces.

  5. Heteromers of amyloid precursor protein in cerebrospinal fluid

    OpenAIRE

    Cuchillo-Ibáñez, Inmaculada; López-Font, Inmaculada; Boix-Amorós, Alba; Brinkmalm, Gunnar; Blennow, Kaj; Molinuevo, José L.; Sáez-Valero, Javier

    2015-01-01

    Background Soluble fragments of the amyloid precursor protein (APP) generated by ?- and ?-secretases, sAPP? and sAPP?, have been postulated as promising new cerebrospinal fluid (CSF) biomarkers for the clinical diagnosis of Alzheimer?s disease (AD). However, the capacity of these soluble proteins to assemble has not been explored and could be relevant. Our aim is to characterize possible sAPP oligomers that could contribute to the quantification of sAPP? and sAPP? in CSF by ELISA, as well as ...

  6. One-dimensional Nanostructured Materials From Organic Precursor

    Institute of Scientific and Technical Information of China (English)

    K. F. Cai

    2005-01-01

    @@ 1Introduction One-dimensional nanostructured materials, such as nanowires, nanobelts, nanotubes and nanocables have been attracting a great research interest in the last decade due to their superior electrical, optical, mechanical and thermal properties, and many methods have been explored to synthesis of the materials, e.g., arc discharge, laser ablation, chemical vapor deposition, thermal evaporation, sol-gel method, template method and so on. In this work, we present a novel and simple method to one-dimensional nanostructured materials by pyrolysis of organic precursor.

  7. Surface reconstruction precursor to melting in Au309 clusters

    Directory of Open Access Journals (Sweden)

    Fuyi Chen

    2011-09-01

    Full Text Available The melting of gold cluster is one of essential properties of nanoparticles and revisited to clarify the role played by the surface facets in the melting transition by molecular dynamics simulations. The occurrence of elaborate surface reconstruction is observed using many-body Gupta potential as energetic model for 309-atom (2.6 nm decahedral, cuboctahedral and icosahedral gold clusters. Our results reveal for the first time a surface reconstruction as precursor to the melting transitions. The surface reconstruction lead to an enhanced melting temperature for (100 faceted decahedral and cuboctahedral cluster than (111 faceted icosahedral gold cluster, which form a liquid patch due to surface vacancy.

  8. Graphene nanoribbons synthesized from molecular precursor polymerization on Au(110)

    Energy Technology Data Exchange (ETDEWEB)

    Massimi, Lorenzo; Ourdjini, Oualid; Della Pia, Ada; Mariani, Carlo; Betti, Maria Grazia [Dipartimento di Fisica, Università di Roma La Sapienza, Piazzale Aldo Moro 2, I - 00185 Roma (Italy); Cavaliere, Emanuele; Gavioli, Luca [i-LAMP & Dipartimento di Matematica e Fisica, Università Cattolica, 25121 Brescia (Italy)

    2015-06-23

    A spectroscopic study of 10,10-dibromo-9,9 bianthracene (DBBA) molecules deposited on the Au(110) surface is presented, by means of ultraviolet and X-ray photoemission, and X-ray absorption spectroscopy. Through a thermally activated procedure, these molecular precursors polymerize and eventually form graphene nanoribbons (GNRs) with atomically controlled shape and width, very important building blocks for several technological applications. The GNRs observed by scanning tunneling microscopy (STM) appear as short segments on top of the gold surface reconstruction, pointing out the delicate balance among surface diffusion and surface corrugation in their synthesis on the Au(110) surface.

  9. Synthesis of carbon nanotubes using natural carbon precursor: Castor oil

    Science.gov (United States)

    Raziah, A. Z.; Junizah, A. R.; Saifuddin, N.

    2012-09-01

    Castor oil has long been an article of commerce due to its versatility as it is widely used as a starting material for many industrial chemical products because of its unique structure. In this study, carbon nanotubes has been synthesized by thermal decomposition of castor oil in nitrogen atmosphere at 300-400δC using custom-made microwave processing unit. The precursor material was catalyzed by iron clusters originating from the addition of ferrocene. The morphology and characterization of the CNTs were studied and discussed by transmission electron microscopy (TEM).

  10. Imaging Transition Zone Thickness Beneath South America from SS Precursors

    Science.gov (United States)

    Schmerr, N.; Garnero, E.

    2006-12-01

    We image detailed upper mantle discontinuity structure beneath a number of geologically active regions, including the South American subduction zone, the Scotia plate subduction zone, and several volcanic hotspots (e.g., the Galapagos Islands), in a region ~10,000 km by 10,000 km wide, spanning 70° S to 20° N and 20° W to 110° W. Precursors to the seismic phase SS are analyzed, which form as a result of underside reflections off seismic discontinuities beneath the midpoint of the SS path and are highly sensitive to discontinuity depth and sharpness. Our SS dataset consists of over 15,000 high-quality transverse component broadband displacement seismograms collected from the Incorporated Research Institutions for Seismology (IRIS), the Canadian National Seismic Network (CNSN), as well as data from EarthScope seismic stations, and from the Canadian Northwest Experiment (CANOE) temporary broadband array deployment. This dataset densely samples several regions in our study area and significantly improves the sampling for this area compared to previous precursor studies. Data with common central SS bouncepoints are stacked to enhance precursory phases. Solution discontinuity structure depends on a number of factors, including dominant seismic period, crustal correction, signal-to-noise ratio threshold, and tomography model used for mantle heterogeneity correction. We exclude precursor data predicted to interfere with other seismic phases, such as topside reflections (e.g., s670sS), which have been demonstrated to contaminate final stacks. Solution transition zone thickness is at least 20 km thicker than global average estimates of 242 km along the northwestern portion of the South American subduction complex (Peru, Ecuador, and Columbia); this thickening extends 1000-1500 km to the east beneath the continent, but does not appear to continue south of -20° latitude along the convergent margin. A minimum of 10 km of thickening is imaged to the west of the Scotia

  11. CVD of pure copper films from amidinate precursor

    OpenAIRE

    2009-01-01

    Copper(I) amidinate [Cu(i-Pr-Me-AMD)]2 was investigated to produce copper films in conventional low pressure chemical vapor deposition (CVD) using hydrogen as reducing gas-reagent. Copper films were deposited on steel, silicon, and SiO2/Si substrates in the temperature range 200–350°C at a total pressure of 1333 Pa. The growth rate on steel follows the surface reaction between atomic hydrogen and the entire precursor molecule up to 240°C. A significant increase of the growth rate at tempera...

  12. Selective Manipulation of Microscopic Particles with Precursor Swirling Rayleigh Waves

    Science.gov (United States)

    Riaud, Antoine; Baudoin, Michael; Bou Matar, Olivier; Becerra, Loic; Thomas, Jean-Louis

    2017-02-01

    Contactless manipulation of microparticles is demonstrated with single-beam acoustical tweezers based on precursor swirling Rayleigh waves. These surface waves degenerate into acoustical vortices when crossing a stack made of a fluid layer and its solid support, hence creating a localized acoustical trap in a fluid cavity. They can be synthesized with a single interdigitated transducer whose spiraling shape encodes the phase of the field like a hologram. For applications, these tweezers have many attractive features: they are selective, flat, easily integrable, and compatible with disposable substrates.

  13. Coal-based carbon foams. Influence of the precursor coal

    Energy Technology Data Exchange (ETDEWEB)

    Montserrat Calvo; Roberto Garcia; Sabino R. Moinelo [Instituto Nacional del Carbon (CSIC), Oviedo (Spain)

    2007-07-01

    Carbon foams were obtained from several bituminous coals with different plasticity and volatile matter content by a two-stage thermal process. The first stage, a controlled carbonisation treatment under pressure at 450-500{sup o}C, is responsible for the final textural properties of the foam. In the second stage the carbonisation product was baked at 1100{sup o}C. The foams produced display a macroporous texture with plasticity, volatile matter content and maceral composition of the precursor coals having an influence on the apparent density and the pore size of the resultant porous products. 7 refs., 4 figs., 3 tabs.

  14. Survey of volatile oxylipins and their biosynthetic precursors in bryophytes.

    Science.gov (United States)

    Croisier, Emmanuel; Rempt, Martin; Pohnert, Georg

    2010-04-01

    Oxylipins are metabolites which are derived from the oxidative fragmentation of polyunsaturated fatty acids. These metabolites play central roles in plant hormonal regulation and defense. Here we survey the production of volatile oxylipins in bryophytes and report the production of a high structural variety of C5, C6, C8 and C9 volatiles of mosses. In liverworts and hornworts oxylipin production was not as pronounced as in the 23 screened mosses. A biosynthetic investigation revealed that both, C18 and C20 fatty acids serve as precursors for the volatile oxylipins that are mainly produced after mechanical wounding of the green tissue of mosses.

  15. A Precursor of Modern Economic Thought: Antoine Laurent de Lavoisier

    Directory of Open Access Journals (Sweden)

    Andreea VASILIU

    2011-02-01

    Full Text Available In the context of development of economic relations, national accounting is a necessity. Building a system of information on gross domestic product, size of national wealth, financial relations and cash flows determine studies on the economic forecast, the distribution and accumulation of national wealth. Efforts in this direction have been numerous and have their roots in the work of Antoine Laurent Lavoisier . He was he who first promulgated the concepts and specific national accounting methods. He was a precursor of modern economic thought.

  16. Ozone precursors have regionally variable effect on radiative forcing

    Science.gov (United States)

    Schultz, Colin

    2013-02-01

    When released near the surface, carbon monoxide, assorted nitrogen oxides (NOx ), and nonmethane hydrocarbons (NMHC) contribute to the production of ozone, a key component of photochemical smog, which is known to have serious deleterious effects on human health. However, when ozone gets lifted into the troposphere, it is a greenhouse gas. That these ozone precursors have such a dual-pronged effect—affecting both human health and the global radiation budget—suggests that mitigating their emissions could be a potential method to both improve air quality and dampen the rate of anthropogenic climate change.

  17. Transcriptional activators enhance polyadenylation of mRNA precursors

    OpenAIRE

    Nagaike, Takashi; Manley, James L.

    2011-01-01

    3′ processing of mRNA precursors is frequently coupled to transcription by RNA polymerase II (RNAP II). This coupling is well known to involve the C-terminal domain of the RNAP II largest subunit, but a variety of other transcription-associated factors have also been suggested to mediate coupling. Our recent studies have provided direct evidence that transcriptional activators can enhance the efficiency of transcription-coupled 3′ processing. In this point-of-view, we discuss the mechanisms t...

  18. Role of a Serotonin Precursor in Development of Gut Microvilli

    OpenAIRE

    Nakamura, Kazuhiro; Sato, Taku; Ohashi, Akiko; Tsurui, Hiromichi; Hasegawa, Hiroyuki

    2008-01-01

    Monoamines exert diverse functions in various cells in peripheral organs as well as in the central nervous system. 5-Hydroxy-l-tryptophan (5-HTP) has been simply regarded as a precursor of serotonin, and it is believed that the biological significance of 5-HTP is essentially ascribable to the production of serotonin. Systemic treatment with 5-HTP is often applied to patients with low serotonin levels in the brain. Here we show that endogenous and exogenous 5-HTP but not serotonin induced the ...

  19. Dos madres adolescentes, dos vínculos: ¿qué marca la diferencia?

    Directory of Open Access Journals (Sweden)

    Pierina Traverso K.

    2007-06-01

    Full Text Available Se presenta un estudio de caso de dos madres adolescentes de la misma edad (17 años, con el cual se intenta explorar las representaciones maternas y las interacciones madre-bebe, es decir, las distintas maneras de “estar con” el bebe. El estudio pretende discutir que la maternidad adolescente en sí misma no es un factor de riesgo, sino que otras variables moderadoras como la calidad de las redes de sostenimiento y la función reflexiva con que cada joven madre cuenta. Las representaciones maternas fueron evaluadas a través de una entrevista semi-estructurada sobre representaciones maternas (Traverso, 2006 y las interacciones madre-bebe fueron medidas y filmadas a través del Mother-Infant Global-Ratings para dos y cuatro meses (Murray, Fiori-Cowley & Cooper, 1996.---A case study of two adolescent mothers of the same age is presented (17 years old with which it is intended to explore the maternal representations and mother-baby interactions, that is, the different ways of “being with” a baby. The study pretends to discuss that it is not adolescent motherhood in itself a risk factor, but other mediating variables such as supportnetwork and the reflective function with which each young mother counts. Maternal representations were assessed through a semi-structured interview about maternal representations (Traverso, 2006 and the mother-infant interactions were measured and filmed through the Mother-Infant Global Ratings for two and four months (Murray, Fiori-Cowley & Cooper, 1996.

  20. MOBILE MARKETING: A NOVA ABORDAGEM DOS MARKETEERS E DOS NOVOS TURISTAS

    Directory of Open Access Journals (Sweden)

    Marco Paula Pinto

    2014-12-01

    Full Text Available O Mobile Marketing é uma das áreas do marketing digital que apresenta mais potencialidades para as empresas, em geral e em particular para as da área do turismo. Permite a criação de um canal direto com o cliente, que lhe permite adquirir um estilo de vida mais versátil uma vez que lhe facilita a aquisição de produtos únicos graças à possibilidade de personalização, conetividade e mobilidade em qualquer lugar e a qualquer hora. O presente estudo tem como objetivo a sensibilização da importância do marketing digital para as empresas, principalmente das relacionadas com a atividade turística, o qual apresenta as características e identifica as potencialidades das funcionalidades associadas, bem como a evolução dos dipositivos móveis até ao impacto que as tecnologias mobile poderão causar nas empresas e na sociedade atual. No presente artigo, concluiu-se que a tecnologia está cada vez mais presente na sociedade e concede vantagens competitivas às empresas em termos de versatilidade, personalização e divulgação dos seus produtos através de um canal direto e em tempo real com o cliente, através de um dispositivo móvel que cada vez mais é considerado um acessório necessário para os consumidores.

  1. A Metodologia Coso como Ferramenta de Gerenciamento dos Controles Internos

    Directory of Open Access Journals (Sweden)

    Rômulo Paiva Farias

    2009-12-01

    Full Text Available O controle interno é tema em discussão nos meios empresarial e acadêmico. A pesquisa retrata a utilização de uma das principais frameworks para gerenciamento de controles internos, o Committee of Sponsoring Organizations of the Treadway Commission (Coso, e tem como objetivo geral analisar a adequação da metodologia Coso no gerenciamento dos controles internos do Banco do Brasil (BB, na visão dos gerentes de agência. Trata-se de pesquisa de natureza qualitativa, utilizando-se os procedimentos de pesquisa documental e aplicação de estudo de caso único. Foram analisadas questões relacionadas à adequação da metodologia Coso no gerenciamento dos controles internos do BB quanto aos seguintes aspectos: processo de gestão e objetivos estratégicos; eficiência e efetividade operacional; confiabilidade dos registros contábeis e financeiros; e conformidade com leis e normativos aplicáveis à entidade. Concluiu-se que, do ponto de vista dos gerentes de agência pesquisados, a metodologia Coso no gerenciamento dos controles internos do BB é adequada e alinha-se aos interesses da estrutura e da cultura de controle interno propostas pelo banco.

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

    Directory of Open Access Journals (Sweden)

    O. Juliao

    1991-12-01

    Full Text Available Este estudio compara la inmunogenicidad (seroconversión, seroprotección e Hiperrespuesta, producida por dos vacunas recombinantes contra la hepatitis B (Engerix-B de Bélgica y Cubana, en dos esquemas (012 y 016 meses, empleando los métodos de cuantificación para Anti-HBsAg (Abbott y Organón, los cuales fueron también comparados. En el estudio participaron 257 voluntarios,  divididos al azar en 4 grupos (dos vacunas, dos esquemas. Resultados: los dos métodos de Abbon y Organon, no presentan diferencias estadísticas significativas. La vacuna cubana muestra una mayor respuesta inmunogénica para dos dosis de vacuna y para el esquema 012. No hay diferencia entre los esquemas 012 y 016 y en el esquema 016 no se ven diferencias estadísticamente significativas con la vacuna Engerix-B. En esta Última el esquema 016 muestra mejores resultados que el 012.

  3. A redução dos riscos dos pesticidas pela protecção integrada

    OpenAIRE

    Amaro, Pedro

    2003-01-01

    Os pesticidas de uso agrícola tiveram grande expansão após a 2.ª Guerra Mundial, graças à descoberta e amplo desenvolvimento e aplicação pelos agricultores dos novos pesticidas organossintéticos. A sua fácil aplicação, o apoio eficiente dos técnicos das empresas de pesticidas e, por vezes, dos serviços oficiais e as evidentes vantagens de maior eficácia e de carácter económico justificam a grande expansão do consumo destes pesticidas a partir dos anos 50, 60 e 70. É bem c...

  4. Methods of making copper selenium precursor compositions with a targeted copper selenide content and precursor compositions and thin films resulting therefrom

    Energy Technology Data Exchange (ETDEWEB)

    Curtis, Calvin J. (Lakewood, CO); Miedaner, Alexander (Boulder, CO); van Hest, Marinus Franciscus Antonius Maria (Lakewood, CO); Ginley, David S. (Evergreen, CO); Leisch, Jennifer (Denver, CO); Taylor, Matthew (West Simsbury, CT); Stanbery, Billy J. (Austin, TX)

    2011-09-20

    Precursor compositions containing copper and selenium suitable for deposition on a substrate to form thin films suitable for semi-conductor applications. Methods of forming the precursor compositions using primary amine solvents and methods of forming the thin films wherein the selection of temperature and duration of heating controls the formation of a targeted species of copper selenide.

  5. Total N-nitrosamine Precursor Adsorption with Carbon Nanotubes: Elucidating Controlling Physiochemical Properties and Developing a Size-Resolved Precursor Surrogate

    Science.gov (United States)

    Needham, Erin Michelle

    As drinking water sources become increasingly impaired with nutrients and wastewater treatment plant (WWTP) effluent, formation of disinfection byproducts (DBPs)--such as trihalomethanes (THMs), dihaloacetonitriles (DHANs), and N-nitrosamines--during water treatment may also increase. N-nitrosamines may comprise the bulk of the chronic toxicity in treated drinking waters despite forming at low ng/L levels. This research seeks to elucidate physicochemical properties of carbon nanotubes (CNTs) for removal of DBP precursors, with an emphasis on total N-nitrosamines (TONO). Batch experiments with CNTs were completed to assess adsorption of THM, DHAN, and TONO precursors; physiochemical properties of CNTs were quantified through gas adsorption isotherms and x-ray photoelectron spectroscopy. Numerical modeling was used to elucidate characteristics of CNTs controlling DBP precursor adsorption. Multivariate models developed with unmodified CNTs revealed that surface carboxyl groups and, for TONO precursors, cumulative pore volume (CPV), controlled DBP precursor adsorption. Models developed with modified CNTs revealed that specific surface area controlled adsorption of THM and DHAN precursors while CPV and surface oxygen content were significant for adsorption of TONO precursors. While surrogates of THM and DHAN precursors leverage metrics from UV absorbance and fluorescence spectroscopy, a TONO precursor surrogate has proved elusive. This is important as measurements of TONO formation potential (TONOFP) require large sample volumes and long processing times, which impairs development of treatment processes. TONO precursor surrogates were developed using samples that had undergone oxidative or sorption treatments. Precursors were analyzed with asymmetric flow field-flow fractionation (AF4) with inline fluorescence detection (FLD) and whole water fluorescence excitation-emission matrices (EEMs). TONO precursor surrogates were discovered, capable of predicting changes in

  6. Lacustrine biomass: An significant precursor of high wax oil

    Institute of Scientific and Technical Information of China (English)

    HUANG Haiping; ZHENG Yabin; ZHANG Zhanwen; LI Jinyou

    2003-01-01

    Although a variety of precursors have been proposed for the formation of high molecular weight hydrocarbons (HMWHCs) in crude oil, their precise origin remains elusive. Quantitative studies of macrocrystalline wax and microcrystalline wax content of source rock extracts from the Damintun depression, Liaohe Basin, a typical high wax producing area, coupled with microscopical maceral composition studies and pyrolysis-GC analysis indicate that oil shale enriched in lacustrine biomass makes a primary contribution to wax in oil. The main precursors of high wax oil are lacustrine alginites and their amorphous matrix, which are highly aliphatic in nature and have high generative potential for HMWHCs. Wax generation efficiency could be affected by organic material abundance and maturity. The high abundance and low maturity of organic material are favorite for the formation of high quantity of wax, which declines with decreasing organic abundance and increasing thermal maturity. This suggests that wax is derived from organic-rich lacustrine biomass at early stages of maturation (RO = 0.4%-0.7%). Although the contribution of high plant cuticular wax and sporopollen cannot be ruled out, lacustrine biomass is more important in the formation of high wax oil.

  7. A common precursor to two major crab neurosecretory peptides.

    Science.gov (United States)

    Stuenkel, E L

    1986-01-01

    The biosynthesis of proteins by the X-organ sinus gland (XOSG) neurosecretory system of the crab, Cardisoma carnifex was studied using the pulse-chase technique. Analysis of radioactive proteins following 2D-PAGE showed that during pulse incubations of less than or equal to 30 min a single predominant 14Kd prohormone was synthesized. With chase less than or equal to 3 hr the primary 14Kd protein was found to undergo differential and/or multiple post-translational modifications prior to its proteolytic cleavage. Increasing the chase to greater than 3 hr showed a shift in labeling from the 14Kd forms to 3 separate 6Kd proteins. Two of the 6Kd proteins were identified as crustacean hyperglycemic peptides (CHH). Similarity in protein labeling using [3H]leucine and [35S]cysteine suggest a second major peptide group, the H peptide, known to lack cysteine, is also contained within the 14Kd precursor. Peptide mapping of the 14Kd proteins and of unlabeled CHH and peptide H provide substantive evidence for this biosynthetic scheme. Thus, both the CHH and H peptide groups, which together constitute greater than 90% of the XOSG peptide content, in this species, arise from a common 14Kd precursor molecule.

  8. An Accident Precursor Analysis Process Tailored for NASA Space Systems

    Science.gov (United States)

    Groen, Frank; Stamatelatos, Michael; Dezfuli, Homayoon; Maggio, Gaspare

    2010-01-01

    Accident Precursor Analysis (APA) serves as the bridge between existing risk modeling activities, which are often based on historical or generic failure statistics, and system anomalies, which provide crucial information about the failure mechanisms that are actually operative in the system and which may differ in frequency or type from those in the various models. These discrepancies between the models (perceived risk) and the system (actual risk) provide the leading indication of an underappreciated risk. This paper presents an APA process developed specifically for NASA Earth-to-Orbit space systems. The purpose of the process is to identify and characterize potential sources of system risk as evidenced by anomalous events which, although not necessarily presenting an immediate safety impact, may indicate that an unknown or insufficiently understood risk-significant condition exists in the system. Such anomalous events are considered accident precursors because they signal the potential for severe consequences that may occur in the future, due to causes that are discernible from their occurrence today. Their early identification allows them to be integrated into the overall system risk model used to intbrm decisions relating to safety.

  9. Suiciding of lymphocytic precursor cells by tritiated nucleosides, in vitro.

    Science.gov (United States)

    Uyeki, E M; Nishimura, T; Bisel, T U

    1978-02-01

    Differences in suiciding by various tritiated nucleosides were observed between two functional assays for in vitro lymphocytic precursor cell development, the hemolysin plaque-forming cell (PFC) assay and the B lymphocytic colony-forming cell (CFC-L) assay, using BDF1 mouse spleen cells. PFC growth was markedly reduced by an early (days 0-1) pulse of tritiated deoxyadenosine ([3H]dAdo), but relatively unaffected by a pulse of tritiated thymidine ([3H]dThd) during the same interval. In contrast, CFC-L formation significantly dropped after an early (day 0) [3H]dThd pulse, as well as after pulses of [3H]dAdo and the corresponding tritiated ribosides, uridine and adenosine. This implied a cycling state in an early lymphocytic precursor cell, as opposed to the PFC insensitivity to an early [3H]dThd pulse. The response pattern of colonies and clusters to [3H]dThd supported our notion of a delayed suiciding of CFC contributing to the increase in cluster numbers.

  10. Characterization of haloacetic acid precursors in source water.

    Science.gov (United States)

    Kanokkantapong, Vorapot; Marhaba, Taha F; Pavasant, Prasert; Panyapinyophol, Bunyarit

    2006-08-01

    Raw water from the Bangkok (Thailand) main municipal water supply canal was examined for its natural organic composition by fractionation with adsorption resins. DAX-8 resin was the first resin employed to fractionate the hydrophobic fractions. Fractionation at neutral pH resulted in the separation of the hydrophobic neutral components; at a high pH level (approx. 10) separation of the hydrophobic base components occurred; and at a low pH level (approx. 2) the hydrophobic acid components were separated. AG-MP-50 cationic resin was then used to separate the hydrophilic base components, and WA-10, a weak anionic resin, was applied finally to fractionate the hydrophilic acid and neutral components. Subsequently, each fraction was tested for its chlorine disinfection by-product (DBP) formation potential. The HAA formation tests demonstrated that the various organic fractions had different reactivity levels for the formation of haloacetic acids (HAAs). For this source water, the hydrophilic neutral fraction dominated over the other five fractions in being the main organic component and the most significant precursor of HAAs formation. On the other hand, in terms of specific HAA formation potential (FP), the hydrophobic and hydrophilic base fractions were the most reactive precursors to the formation of HAAs. In all cases, the quantity of HAAs formed depended linearly upon the amount of organic constituents in the water sample.

  11. Thermodynamic equilibrium calculation on preparation of copper oxalate precursor powder

    Institute of Scientific and Technical Information of China (English)

    FAN You-qi; ZHANG Chuan-fu; ZHAN Jing; WU Jian-hui

    2008-01-01

    According to the principles of simultaneous equilibrium and mass balance, a series of thermodynamic equilibrium equations of Cu2+ -C2O2-4 -NH3-NH4+-H2O system at ambient temperature were deduced theoretically and the logarithm concentration versus pH value (lg[Cu2+]T-pH) diagrams at different solution compositions were drawn. The results show that when pH is below 5.0, copper ion reacts with C2O42- directly and the morphology of copper precursor powder is of pie-shape; when pH is above 5.0, copper ion coordinates with ammonia, and the precipitation proceeds slowly accompanying with the release of copper ions from the multi-coordinated Cu(NH3)n2+ (n =1, 2, …, 5) and the morphologies of copper precursor powder are respectively of rod aggregation shape (when 5.0<pH<8.0) and of rod-shape (when pH>8.0). Some experiments were performed to confirm the relation between the total concentration of copper ion and pH value. It is shown that the thermodynamic mathematical model is correct and the calculated values are basically accurate.

  12. AMYPdb: A database dedicated to amyloid precursor proteins

    Directory of Open Access Journals (Sweden)

    Delamarche Christian

    2008-06-01

    Full Text Available Abstract Background Misfolding and aggregation of proteins into ordered fibrillar structures is associated with a number of severe pathologies, including Alzheimer's disease, prion diseases, and type II diabetes. The rapid accumulation of knowledge about the sequences and structures of these proteins allows using of in silico methods to investigate the molecular mechanisms of their abnormal conformational changes and assembly. However, such an approach requires the collection of accurate data, which are inconveniently dispersed among several generalist databases. Results We therefore created a free online knowledge database (AMYPdb dedicated to amyloid precursor proteins and we have performed large scale sequence analysis of the included data. Currently, AMYPdb integrates data on 31 families, including 1,705 proteins from nearly 600 organisms. It displays links to more than 2,300 bibliographic references and 1,200 3D-structures. A Wiki system is available to insert data into the database, providing a sharing and collaboration environment. We generated and analyzed 3,621 amino acid sequence patterns, reporting highly specific patterns for each amyloid family, along with patterns likely to be involved in protein misfolding and aggregation. Conclusion AMYPdb is a comprehensive online database aiming at the centralization of bioinformatic data regarding all amyloid proteins and their precursors. Our sequence pattern discovery and analysis approach unveiled protein regions of significant interest. AMYPdb is freely accessible 1.

  13. Novel drug delivery strategies for porphyrins and porphyrin precursors

    Science.gov (United States)

    Morrow, D. I. J.; Donnelly, R. F.

    2009-06-01

    superficial lesions, such as actinic keratosis. In addition, photodynamic antimicrobial chemotherapy (PACT) is attracting increasing interest for the treatment of infection. However, delivery strategies for topical PDT and PACT are still based on application of rather simplistic cream and solution formulations, with little consideration given to thermodynamics, targeting or the physicochemical properties of the active agent. Purpose-designed dosage forms for topical delivery of aminolevulinic acid or its esters include creams containing penetration enhancers and/or iron chelators, pressure sensitive patches and bioadhesive patches. Such systems aim to enhance drug delivery across the stratum corneum and keratinised debris overlying neoplastic lesions and improve subsequent protoporphyrin IX (PpIX) production. The alternative to using porphyrin precursors is the use of pre-formed photosensitisers. However, owing to their relatively high molecular weights, conventional topical application is not appropriate. Innovative strategies, such as the use of needle-free injections and microneedle arrays, bypass the stratum corneum, enabling rapid and targeted delivery not only porphyrin precursors but also pre-formed photosensitisers. This presentation will review drug delivery work published to date in the fields of PDT and PACT. In addition, the benefits of employing the latest advances in pharmaceutical technology will be highlighted.

  14. Silicone Resin Applications for Ceramic Precursors and Composites

    Directory of Open Access Journals (Sweden)

    Masaki Narisawa

    2010-06-01

    Full Text Available This article reviews the applications of silicone resins as ceramic precursors. The historical background of silicone synthesis chemistry is introduced to explain the production costs and supply availability of various silicones. Thermal degradation processes of silicones are classified in terms of the main chain structure and cyclic oligomer expulsion process, which determine the resulting ceramic yield and the chemical composition. The high temperature decomposition of Si-O-C beyond 1,400 °C in an inert atmosphere and formation of a protective silica layer on material surfaces beyond 1,200 °C in an oxidative atmosphere are discussed from the viewpoints of the wide chemical composition of the Si-O-C materials. Applications of the resins for binding agents, as starting materials for porous ceramics, matrix sources with impregnation, fiber spinning and ceramic adhesions are introduced. The recent development of the process of filler or cross-linking agent additions to resin compounds is also introduced. Such resin compounds are useful for obtaining thick coatings, MEMS parts and bulk ceramics, which are difficult to obtain by pyrolysis of simple organometallic precursors without additives.

  15. High-quality CdTe films from nanoparticle precursors

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, D.L.; Pehnt, M.; Urgiles, E. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    1996-05-01

    In this paper the authors demonstrate that nanoparticulate precursors coupled with spray deposition offers an attractive route into electronic materials with improved smoothness, density, and lower processing temperatures. Employing a metathesis approach, cadmium iodide was reacted with sodium telluride in methanol solvent, resulting in the formation of soluble NaI and insoluble CdTe nanoparticles. After appropriate chemical workup, methanol-capped CdTe colloids were isolated. CdTe thin film formation was achieved by spray depositing the nanoparticle colloids (25-75 {Angstrom} diameter) onto substrates at elevated temperatures (T = 280-440{degrees}C) with no further thermal treatment. These films were characterized by x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Cubic CdTe phase formation was observed by XRD, with a contaminant oxide phase also detected. XPS analysis showed that CdTe films produced by this one-step method contained no Na or C and substantial O. AFM gave CdTe grain sizes of {approx}0.1-0.3 {mu}m for film sprayed at 400{degrees}C. A layer-by-layer film growth mechanism proposed for the one-step spray deposition of nanoparticle precursors will be discussed.

  16. Ni+ reactions with aminoacetonitrile, a potential prebiological precursor of glycine

    CERN Document Server

    Lamsabhi, Al Mokhtar; Yáñez, Manuel; Guillemin, Jean-Claude; Haldys, Violette; Tortajada, Jeanine; Salpin, Jean-Yves

    2008-01-01

    The gas-phase reactions between Ni+ (2D5/2) and aminoacetonitrile, a molecule of prebiological interest as possible precursor of glycine, have been investigated by means of mass spectrometry techniques. The mass-analyzed ion kinetic energy (MIKE) spectrum reveals that the adduct ions [NCCH2NH2, Ni+] spontaneously decompose by loosing HCN, H2, and H2CNH, the loss of hydrogen cyanide being clearly dominant. The structures and bonding characteristics of the aminoacetonitrile-Ni+ complexes as well as the different stationary points of the corresponding potential energy surface (PES) have been theoretically studied by density functional theory (DFT) calculations carried out at B3LYP/6-311G(d,p) level. A cyclic intermediate, in which Ni+ is bisligated to the cyano and the amino group, plays an important role in the unimolecular reactivity of these ions, because it is the precursor for the observed losses of HCN and H2CNH. In all mechanisms associated with the loss of H2, the metal acts as hydrogen carrier favoring ...

  17. Superior Thermal Barrier Coatings Using Solution Precursor Plasma Spray

    Science.gov (United States)

    Jordan, E. H.; Xie, L.; Gell, M.; Padture, N. P.; Cetegen, B.; Ozturk, A.; Ma, X.; Roth, J.; Xiao, T. D.; Bryant, P. E. C.

    2004-03-01

    A novel process, solution precursor plasma spray (SPPS), is presented for depositing thermal barrier coatings (TBCs), in which aqueous chemical precursors are injected into a standard direct current plasma spray system. The resulting coatings microstructure has three unique features: (1) ultra fine splats (1 µm), (2) nanometer and micron-sized interconnected porosity, and (3) closely spaced, through-thickness cracks. Coatings over 3 mm thick can be readily deposited using the SPPS process. Coating durability is excellent, with SPPS coatings showing, in furnace cycling tests, 2.5 times the spallation life of air plasma coatings (APS) and 1.5 times the life of electron beam physical vapor deposited (EB-PVD) coatings. The conductivity of SPPS coatings is lower than EB-PVD coatings and higher than the best APS coatings. Manufacturing cost is expected to be similar to APS coatings and much lower than EB-PVD coatings. The SPPS deposition process includes droplet break-up and material arriving at the deposition surface in various physical states ranging from aqueous solution, gel phase, to fully-molten ceramic. The relation between the arrival state of the material and the microstructure is described.

  18. [Natural history of precursor lesions of cervical cancer].

    Science.gov (United States)

    Tranbaloc, P

    2008-06-01

    Precursor lesions of invasive cancer of uterine cervix begin at the squamocolumnar junction. On this zone in permanent transformation, human papillomavirus (HPV) gives condylomatous lesions, pure or associated with neoplasic transformation of the epithelium. For 50 years, various histological classifications have been proposed. First, four groups have been designed: light, moderate, severe dysplasia and in situ carcinoma. Secondly, Richart proposed the cervix intraepithelial neoplasia classification (CIN) with three grades (1 to 3) according to their severity. Progression from CIN 1 to CIN 3 and invasive carcinoma is admitted and is consistent with the concept of lesional continuum. However, because of the elevated rate of spontaneous regression of CIN 1, it is probably a lesion of very low potential aggressivity and its role as a precursor is uncertain. Now two groups of different evolutivity are currently considered: low grade and high grade lesions. The last one's, at the opposite of the first, are monoclonal, have major epithelial abnormalities with sometimes abnormal mitoses and are frequently aneuploid. Aggressivity depends on the persistence of HR HPV more than on progressive morphologic transformation. By integrating in-host genoma, it induces modifications on cellular cycle proteins. Revelation by immunohistochemistry brings help to diagnosis of high grade lesions when traditional morphology is ambiguous.

  19. Precursors in cancer epidemiology: aligning definition and function.

    Science.gov (United States)

    Wacholder, Sholom

    2013-04-01

    A precursor of a disease is a definable pathologic state that progresses directly to disease without a known intermediate step and whose presence substantially increases the likelihood of disease. Precancers, or precursors of cancer, can help provide detail about the dynamic pathogenesis process before clinical disease. Thereby, ascertainment of properly defined precancers can increase precision of estimates and power in epidemiologic and clinical studies. Besides providing targets for direct treatment and improving tools for risk assessment in screening programs, precancers can help establish temporal ordering of cause and effect; can identify relatively homogeneous subsets of cancer that have passed through a given precancer state; and provide a basis for choosing high-risk individuals for detailed longitudinal study. Although the most appropriate definition of the precancer will vary with its function in particular research or clinical applications, the proportion of cancers that progress from the precancer and risk of cancer progressing from the precancer can be important measures of the value of a precancer in translational efforts.

  20. Processing Pisum sativum seed storage protein precursors in vitro

    Institute of Scientific and Technical Information of China (English)

    YANGLIJUN; CDOMONEY; 等

    1990-01-01

    The profile of polypeptides separated by SDS-PAGE from seed of major crop species such as pea(Pisum sativum) is complex,resulting from cleavage (processing) of precursors expressed from multiple copies of genes encoding vicilin and legumin,the major storage globulins.Translation in vitro of mRNAs hybridselected from mid-maturation pea seed RNAs by defined vicilin and legumin cDNA clones provided precursor molecules that were cleaved in vitro by a cell-free protease extract obtained from similar stage seed;the derived polypeptides were of comparable sizes to those observed in vivo.The feasibility of transcribing mRNA in vitro from a cDNA clone and cleavage in vitro of the derived translation products was established for a legumin clone,providing a method for determining polypeptide products of an expressed sequence.This approach will also be useful for characterising cleavage site requirements since modifications an readily be introduced at the DNA level.

  1. Advanced accident sequence precursor analysis level 2 models

    Energy Technology Data Exchange (ETDEWEB)

    Galyean, W.J.; Brownson, D.A.; Rempe, J.L. [and others

    1996-03-01

    The U.S. Nuclear Regulatory Commission Accident Sequence Precursor program pursues the ultimate objective of performing risk significant evaluations on operational events (precursors) occurring in commercial nuclear power plants. To achieve this objective, the Office of Nuclear Regulatory Research is supporting the development of simple probabilistic risk assessment models for all commercial nuclear power plants (NPP) in the U.S. Presently, only simple Level 1 plant models have been developed which estimate core damage frequencies. In order to provide a true risk perspective, the consequences associated with postulated core damage accidents also need to be considered. With the objective of performing risk evaluations in an integrated and consistent manner, a linked event tree approach which propagates the front end results to back end was developed. This approach utilizes simple plant models that analyze the response of the NPP containment structure in the context of a core damage accident, estimate the magnitude and timing of a radioactive release to the environment, and calculate the consequences for a given release. Detailed models and results from previous studies, such as the NUREG-1150 study, are used to quantify these simple models. These simple models are then linked to the existing Level 1 models, and are evaluated using the SAPHIRE code. To demonstrate the approach, prototypic models have been developed for a boiling water reactor, Peach Bottom, and a pressurized water reactor, Zion.

  2. Neural precursors derived from human embryonic stem cells

    Institute of Scientific and Technical Information of China (English)

    Peng Hongmei; Chen Gui'an

    2005-01-01

    Human embryonic stem (hES) cells provide a promising supply of specific cell types for transplantation therapy. We presented here the method to induce differentiation of purified neural precursors from hES cells, hES cells (Line PKU-1 and Line PKU-2) were cultured in suspension in bacteriological Petri dishes, which differentiated into cystic embryoid bodies (EBs).The EBs were then cultured in N2 medium containing bFGF in poly- L-lysine-coated tissue culture dishes for two weeks. The central, small cells with 2-3 short processes of the spreading outgrowth were isolated mechanically and replated. The resulting neurospheres were cultured in suspension for 10 days, then dissociated into single cell suspension with a Pasteur pipette and plated. Cells grew vigorously in an attached way and were passed every 4-5 days. Almost all the cells were proved nestin positive by immunostaining. Following withdrawal of bFGF, they differentiated into neurons expressing β-tubulin isotypeⅢ, GABA, serotonin and synaptophysin.Through induction of PDGF-AA, they differentiated into astrocytes expressing GFAP and oligodendrocytes expressing O4. The results showed that hES cells can differentiate into typical neural precursors expressing the specific marker nestin and capable of generating all three cell types of the central nervous system (CNS) in vitro.

  3. Deposition of copper from Cu(i) and Cu(ii) precursors onto HOPG surface: Role of surface defects and choice of a precursor

    Science.gov (United States)

    Duan, Yichen; Teplyakov, Andrew V.

    2017-02-01

    The surface reactivity of two copper-containing precursors, (Cu(hfac)2 and Cu(hfac)VTMS, where hfac is hexafluoroacetyloacetonate and VTMS is vinyltrimethylsilane), was investigated by dosing the precursors onto a surface of highly ordered pyrolytic graphite (HOPG) at room temperature. The behavior of these precursors on a pristine HOPG was compared to that on a surface activated by ion sputtering and subsequent oxidation to induce controlled surface defects. X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy were used to confirm copper deposition and its surface distribution, and to compare with the results of scanning electron microscopy and atomic force microscopy investigations. As expected, surface defects promote copper deposition; however, the specific structures deposited depend on the deposition precursor. Density functional theory was used to mimic the reactions of each precursor molecule on this surface and to determine the origins of this different reactivity.

  4. Sinterização flash do condutor catiônico beta-alumina sintetizada pelo método dos precursores poliméricos.

    OpenAIRE

    Lorena Batista Caliman

    2015-01-01

    A beta-alumina de sódio é uma cerâmica condutora de íons Na+ utilizada como eletrólito sólido em baterias de sódio para armazenamento de energias intermitentes como energia solar e eólica. Devido ao alto teor de sódio, esse material é instável a altas temperaturas, podendo sofrer variações de composição durante a etapa de sinterização convencional que utiliza altas temperaturas por longos períodos de tempo. A sinterização flash é uma técnica de sinterização ativada por corrente elétrica que p...

  5. Analise dos impactos tecnico-economicos da utilização do piche de alcatrão de eucalipto como precursor de fibras de carbono ativadas

    OpenAIRE

    2000-01-01

    Resumo: Apresenta-se um estudo do processo de obtenção de fibras de carbono ativadas a partir do piche vegetal com objetivo de aumentar valor agregado de sub-produtos da produção de carvão vegetal, abrindo desta forma, a possibilidade de novos mercados para esses sub-produtos. Para tanto, analisou-se através de séries históricas, a evolução da produção de carvão vegetal, sua demanda e oferta, assim como os principais setores consumidores, destacando-se dentre outros o setor industrial. Atravé...

  6. The effect of precursors salts on surface state of Pd/Al2O3 and Pd/CeO2/Al2O3 catalysts

    Directory of Open Access Journals (Sweden)

    André L. Guimarães

    2004-12-01

    Full Text Available The influence of the precursors on the promoting effect of ceria on Pd/Al2O3 catalyst, when ceria is coated over alumina was studied. The reaction of propane oxidation proceeded under different feed conditions and the surface active sites were characterized by X-ray photoelectron spectroscopy (XPS and in situ diffuse reflectance spectroscopy (DRS. XPS and DRS results show that PdO/Pd0 interface are the active sites independent of the precursor, while the catalysts containing CeO2 showed formation of palladium species in the highest oxidation state, probably PdO2 (338 eV after the oxidation of propane. Besides, the O/Al and O/Ce ratios evidenced the increase of oxygen storage in the presence of CeO2. In addition, the precursor acetylacetonate favors the oxygen storage in the lattice.Estudo da influência dos precursores sobre os catalisadores de Pd/Al2O3 promovidos com céria ancorado sobre a alumina. A oxidação do propano foi feita sob diferentes condições de alimentação sendo caracterizados os sítios superficiais por Espectroscopia Fotoeletrônica de raios X (XPS e por Refletância Difusa em ''situ''. Resultados de XPS e DRS mostraram a formação de interfaces de PdO/Pd0 como sendo os sítios ativos, independentes do precursor utilizado na preparação, enquanto que os catalisadores contendo CeO2 mostraram a formação de espécies de paládio com estado de oxidação mais altos, provavelmente PdO2 (338 eV após a oxidação do propano. Além disso, as razões O/Al e O/Ce evidenciaram um aumento de oxigênio armazenado na presença de CeO2. O precursor acetilacetonato favoreceu o armazenamento de oxigênio na rede.

  7. Methods of forming single source precursors, methods of forming polymeric single source precursors, and single source precursors formed by such methods

    Energy Technology Data Exchange (ETDEWEB)

    Fox, Robert V.; Rodriguez, Rene G.; Pak, Joshua J.; Sun, Chivin; Margulieux, Kelsey R.; Holland, Andrew W.

    2016-04-19

    Methods of forming single source precursors (SSPs) include forming intermediate products having the empirical formula 1/2{L.sub.2N(.mu.-X).sub.2M'X.sub.2}.sub.2, and reacting MER with the intermediate products to form SSPs of the formula L.sub.2N(.mu.-ER).sub.2M'(ER).sub.2, wherein L is a Lewis base, M is a Group IA atom, N is a Group IB atom, M' is a Group IIIB atom, each E is a Group VIB atom, each X is a Group VIIA atom or a nitrate group, and each R group is an alkyl, aryl, vinyl, (per)fluoro alkyl, (per)fluoro aryl, silane, or carbamato group. Methods of forming polymeric or copolymeric SSPs include reacting at least one of HE.sup.1R.sup.1E.sup.1H and MER with one or more substances having the empirical formula L.sub.2N(.mu.-ER).sub.2M'(ER).sub.2 or L.sub.2N(.mu.-X).sub.2M'(X).sub.2 to form a polymeric or copolymeric SSP. New SSPs and intermediate products are formed by such methods.

  8. Mielencefalite espontânea dos camundongos

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    Hermínio Linhares

    1944-02-01

    Full Text Available 1 — Duas amostras de vírus capazes de produzir uma mielencefalite foram isoladas de dois camundongos brancos suíços, de criação, espontâneamente infetados, em um total de 7.000 animais examinados; uma terceira amostra foi obtida por trituração e filtração dos intestinos de camundongos aparentemente normais. 2 — Foram feitas separadamente dez passagens por inoculação intra¬cerebral em camundongos jovens e adultos. Verificou-se por testes de imunidade cruzada que as três amostras eram idênticas. Prossegiu-se então nas passagens com apenas uma das amostras. 3 — O poder infetante aumenta com o número de passagens: o período médio de incubação diminui e aumenta a letalidade. 4 — A infecção espontânea e experimental é descrita. A doença parece ser mais comum em animais jovens. O período de incubação varia de 5 a 30 dias. Às vêzes observa-se uma fase prodromica: fraqueza, menor atividade, dificuldade em andar; geralmente surge a paralisia flácida sem sintomas prévios, na grande maioria das vêzes, nos membros posteriores. Três formas clínicas foram observadas: super-aguda, aguda e crônica. 5 — Em camundongos normais o vírus pode ser demonstrado nas fezes e nos intestinos. Ele é comum no tubo digestivo e só ocasionalmente invade o sistema nervoso central, ou melhor, a encefalomielite e primàriamente uma doença do trato digestivo no qual a invasão do SNC é um acidente. 6 — O vírus passa através de velas de CHAMBERLAND L3 e L5, em BER KEFED V, N e W e em filtro Seitz EK, a suspensão sendo tão ativa como antes da filtração. Conserva-se bem em glicerina a 50% pelo menos 60 dias, se guardado na geladeira. Suspensão de cérebro e medula aquecida em banho-maria a 56°C por 30 minutos perde a atividade. 7 — O título variou entre 4.000 e 20.000 dmm. 8 — Obteve-se infecção por inoculação intracerebral, por instilação nasal e, com menos regularidade, por inoculação intraperitoneal; a via g

  9. Prediction of viral microRNA precursors based on human microRNA precursor sequence and structural features.

    Science.gov (United States)

    Kumar, Shiva; Ansari, Faraz A; Scaria, Vinod

    2009-08-20

    MicroRNAs (small approximately 22 nucleotide long non-coding endogenous RNAs) have recently attracted immense attention as critical regulators of gene expression in multi-cellular eukaryotes, especially in humans. Recent studies have proved that viruses also express microRNAs, which are thought to contribute to the intricate mechanisms of host-pathogen interactions. Computational predictions have greatly accelerated the discovery of microRNAs. However, most of these widely used tools are dependent on structural features and sequence conservation which limits their use in discovering novel virus expressed microRNAs and non-conserved eukaryotic microRNAs. In this work an efficient prediction method is developed based on the hypothesis that sequence and structure features which discriminate between host microRNA precursor hairpins and pseudo microRNAs are shared by viral microRNA as they depend on host machinery for the processing of microRNA precursors. The proposed method has been found to be more efficient than recently reported ab-initio methods for predicting viral microRNAs and microRNAs expressed by mammals.

  10. Efeito da adição de dopantes durante a síntese do precursor columbita para a preparação da cerâmica ferroelétrica relaxora PMN Effect of the doping addition in the synthesis of the columbite precursor for preparation of the PMN relaxor ferroelectric ceramic

    Directory of Open Access Journals (Sweden)

    A. A. Cavalheiro

    1999-12-01

    Full Text Available O Niobato de Chumbo e Magnésio (PMN é um material que possui propriedades ferroelétricas de relaxação. Essa propriedade pode ser acentuada ou alterada mediante a adição de dopantes. Neste trabalho foi demonstrado como a adição dos íons Ba2+/Ti4+ e Pb2+/Ti4+, ou somente o íon K+, altera as características do precursor columbita obtido pelo método Pechini e da cerâmica PMN. Através da análise dos resultados obtidos por DRX e IV, constatou-se que a dopagem com os pares de íons Ba2+/Ti4+ e Pb2+/Ti4+ leva à retenção de maior quantidade de matéria orgânica nos carvões precursores e à formação de fases secundárias. Quando adiciona-se somente o íon K+, o comportamento do precursor columbita é similar ao puro. No entanto, seus efeitos positivos podem ser verificados na cerâmica PMN, como o aumento no tamanho de grão e a elevação em Tm.Lead Magnesium Niobate (PMN is a ferroelectric with relaxation properties. These properties can be improved or modified by doping. In this work is showed that Ba2+/Ti4+ and Pb2+/Ti4+ ions or only K+ ion change the characteristics of columbite precursor prepared by Pechini’s method. The results obtained by XRD and FT-IR show that there is more retention of organic matter in the Ba2+/Ti4+ and Pb2+/Ti4+-MN doped precursors than in the pure one. It was also possible to show that K+-MN doped powders exhibit characteristics similar to pure MN powder, but in the PMN ceramic there is positive effects. The size grain and Tm increase when K+ ion is used on the PMN synthesis.

  11. Disturbances in LF radio-signals as seismic precursors

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    S. P. Kingsley

    2001-06-01

    Full Text Available Low Frequency (LF radio signals lie in the band 30-300 kHz. Monitoring equipment able to measure the electric strength of such signals, at field sites with very low noise levels, were designed and assembled in Italy. From 1993 onwards, the electric field strength of the MCO (216 kHz, France broadcasting station has been measured at two sites in Central Italy. At the end of 1996, radio signals from the CLT (189 kHz, Italy and the CZE (270 kHz, Czech Republic broadcasting stations were included in the measurements. During this monitoring period, evident attenuation of the electric field strength in some of the radio signals was observed at some of the receivers. The duration of the attenuation observed was several days and so it could have been related to particular meteorological conditions. On the other hand, this phenomenon could also represent precursors of moderate (3.0 =M =3.5 earthquakes that occurred near the receivers (within 50 km along the transmitter-receiver path. In this case it is possible that some local troposphere defocusing of the radio signals, produced by the pre-seismic processes, might have occurred. These observations were related only to moderate earthquakes and in these cases it may be that suitable meteorological conditions are needed to observe the effect. During February-March 1998 at one measuring site, we observed a significant increase in the CZE electric field strength. Unfortunately, the data of the other receiver could not be used in this case because of frequent interruptions in the recordings. The increase might have been a precursor of a strong earthquake (M = 5.3 that occurred on March 26, 1998 in the Umbria-Marche zone at a location over 100 km from the receiver, but which lay along the transmitter-receiver path. In this case, it is possible that an ionospheric disturbance, produced by the pre-seismic processes, might have occurred. If this pre-seismic behaviour of the LF signals could be confirmed then this

  12. MetNet Precursor - Network Mission to Mars

    Science.gov (United States)

    Harri, Arri-Matti

    2010-05-01

    We are developing a new kind of planetary exploration mission for Mars - MetNet in situ observation network based on a new semi-hard landing vehicle called the Met-Net Lander (MNL). The first MetNet vehicle, MetNet Precursor, slated for launch in 2011. The MetNet development work started already in 2001. The actual practical Precursor Mission development work started in January 2009 with participation from various space research institutes and agencies. The scientific rationale and goals as well as key mission solutions will be discussed. The eventual scope of the MetNet Mission is to deploy some 20 MNLs on the Martian surface using inflatable descent system structures, which will be supported by observations from the orbit around Mars. Currently we are working on the MetNet Mars Precursor Mission (MMPM) to deploy one MetNet Lander to Mars in the 2011 launch window as a technology and science demonstration mission. The MNL will have a versatile science payload focused on the atmospheric science of Mars. Time-resolved in situ Martian meteorological measurements acquired by the Viking, Mars Pathfinder and Phoenix landers and remote sensing observations by the Mariner 9, Viking, Mars Global Surveyor, Mars Odyssey and the Mars Express orbiters have provided the basis for our current understanding of the behavior of weather and climate on Mars. However, the available amount of data is still scarce and a wealth of additional in situ observations are needed on varying types of Martian orography, terrain and altitude spanning all latitudes and longitudes to address microscale and mesoscale atmospheric phenomena. Detailed characterization of the Martian atmospheric circulation patterns and climatological cycles requires simultaneous in situ atmospheric observations. The scientific payload of the MetNet Mission encompasses separate instrument packages for the atmospheric entry and descent phase and for the surface operation phase. The MetNet mission concept and key probe

  13. DISCURSO, IDENTIDADE E SUBJETIVIDADE EM O CANDIDATO DOS POBRES

    Directory of Open Access Journals (Sweden)

    WELISSON MARQUES

    2011-01-01

    Full Text Available Propomos por meio deste artigo refletir, a priori, acerca da noção de identidade advinda dos estudos sociológicos, seguindo as reflexões de Hall (2006, Bauman (2005, Silva (2007 e Woodward (2007, como também de subjetividade a partir dos estudos de Foucault (1984; 1992; 1994; 1997 2007, e pensar a pertinência destes conceitos como complementares e que coadunam com a noção de sujeito segundo a perspectiva discursiva. Apresentaremos também uma breve reflexão sobre a noção de poder em Foucault, cuja proficuidade se dá na Análise do Discurso uma vez que o poder é constitutivo dos discursos do sujeito-enunciador. Por fim, pautados nos conceitos aqui bosquejados, empreenderemos uma breve análise de um artigo intitulado O Candidato dos Pobres publicado pela revista Veja e que faz referência ao presidente Lula no contexto do escândalo do mensalão. Destarte, percebemos por meio dos recortes analisados que o sujeito enunciador se utiliza de diversas estratégias como forma de conspurcação de seu referente - o presidente Lula.

  14. Perspectivas para a pesquisa em contabilidade: o impacto dos derivativos

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    Alexsandro Broedel Lopes

    2001-08-01

    Full Text Available Este artigo analisa o impacto dos instrumentos financeiros derivativos para a pesquisa em contabilidade. O impacto dos derivativos é grande independentemente da linha de pesquisa adotada. Dentro do paradigma do mercado de capitais, o papel dos derivativos como antecipadores do comportamento futuro dos preços fornece oportunidades interessantes de investigação, por exemplo. Na linha de pesquisa institucional e social o tratamento contábil de tais instrumentos é visualizado tendo-se por base a busca por poder e legitimização da profissão. As características operacionais dos produtos, ambiente de regulamentação, evolução tecnológica e outros aspectos característicos fazem desses produtos bases promissoras para investigações futuras.This paper investigates the role of derivative financial instruments for the future of financial accounting research. This impact is relevant what all major research paradigms are concerned. In capital market-based research, derivative instruments play a central role in price discovery. From the institutional and social points-of-view, derivatives are components of a greater quest for legitimization and power. Their operational features, regulatory environment, technological advances and other characteristics are turning derivatives into promising research venues.

  15. O direito dos povos: uma proposta de sociedade bem ordenada

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    Jéssica de Farias Mesquita

    2017-02-01

    Full Text Available O presente texto tem como objetivo examinar a visão de John Rawls acerca das sociedades bem ordenadas na obra O Direito dos Povos, bem como o significado destas para o desenvolvimento da proposta de sociedade democrática liberal. Rawls, na primeira parte da obra, que trata sobre a teoria ideal, refere-se à ideia geral de contrato social nas Sociedades dos Povos democráticos liberais. O autor prossegue com a mesma ideia, na segunda parte da obra quando trata da teoria não-ideal, referindo-se aos povos decentes. Uma sociedade dos povos decentes, segundo Rawls, é uma sociedade cujas características são aceitáveis como membro de uma Sociedade dos Povos razoável, embora não seja uma sociedade democrática liberal. Ambas as sociedades, seja ela democrática liberal ou decente, fazem parte de uma sociedade bem ordenada por obedecerem aos critérios estabelecidos pela Sociedade dos Povos. Para a garantia de uma sociedade bem ordenada, Rawls expõe uma série de condições para que esse tipo de sociedade seja possível, uma dessas condições é o modo como essas sociedades se encontram reguladas.

  16. Electrostaticspray preparation and properties of RDX/DOS composites

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    Jian Yao

    2017-08-01

    Full Text Available A composite explosive based on 1, 3, 5-trinitro-1, 3, 5-triazinane (RDX was prepared by electrostaticspray method with dioctyl sebacate (DOS as desensitizer. After preparation, the particle size and crystal structure were characterized and chemical features, such as chemical bonds, functional groups, thermal decomposition parameters and mechanical sensitivity were investigated as well. In terms of the morphologies of the composites, the particle sizes were in the range of 1–3 μm. Compared with RDX, the crystal types, chemical bonds and functional groups of the RDX/DOS composites were unchanged. The activation energy of the composites was lower than that of raw RDX, and the 3wt % DOS composites had the lowest activation energy. The impact sensitivity and friction sensitivity of the RDX/DOS composites were lower than those of raw RDX, and the 10wt% DOS composites had the highest H50 (125.9 cm and the lowest friction sensitivity (8%.

  17. Sobrecarga dos cuidadores de idosos com acidente vascular cerebral

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    Roberta Amorim Pereira

    2013-02-01

    Full Text Available O objetivo deste estudo foi avaliar a sobrecarga dos cuidadores de idosos com acidente vascular cerebral (AVC, assim como correlacioná-la com as horas de cuidado, a idade e a independência funcional dos idosos. Trata-se de estudo transversal feito com 62 idosos com AVC e seus cuidadores. O instrumento continha variáveis sociodemográficas e econômicas, Mini-Exame do Estado Mental, Medida da Independência Funcional (MIF e a Escala de Zarit. A possível correlação entre os escores da escala de Zarit e as outras variáveis foi avaliada por meio do Coeficiente de Correlação de Pearson. A maioria dos cuidadores era adultos, filhos, casados e do sexo feminino. A média do escore de Zarit foi 34,92 (15,8. A MIF apresentou correlação negativa com a sobrecarga do cuidador, porém, não houve correlação com a idade e as horas de cuidado. A sobrecarga da maioria dos cuidadores variou de moderada a severa e parece estar relacionada ao nível de independência funcional dos idosos.

  18. Sobrecarga dos cuidadores de idosos com acidente vascular cerebral

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    Roberta Amorim Pereira

    Full Text Available O objetivo deste estudo foi avaliar a sobrecarga dos cuidadores de idosos com acidente vascular cerebral (AVC, assim como correlacioná-la com as horas de cuidado, a idade e a independência funcional dos idosos. Trata-se de estudo transversal feito com 62 idosos com AVC e seus cuidadores. O instrumento continha variáveis sociodemográficas e econômicas, Mini-Exame do Estado Mental, Medida da Independência Funcional (MIF e a Escala de Zarit. A possível correlação entre os escores da escala de Zarit e as outras variáveis foi avaliada por meio do Coeficiente de Correlação de Pearson. A maioria dos cuidadores era adultos, filhos, casados e do sexo feminino. A média do escore de Zarit foi 34,92 (15,8. A MIF apresentou correlação negativa com a sobrecarga do cuidador, porém, não houve correlação com a idade e as horas de cuidado. A sobrecarga da maioria dos cuidadores variou de moderada a severa e parece estar relacionada ao nível de independência funcional dos idosos.

  19. Igualdade na diversidade: a luta pelo reconhecimento dos direitos dos homossexuais no Brasil

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    Osvaldo F. R. L. Fernandez

    2011-08-01

    Full Text Available Este artigo procura refletir sobre como a sistemática discriminação e violência contra os homossexuais, o que impede o próprio incremento da cidadania no Brasil, pois torna estruturalmente sancionada a exclusão e a desigualdade social. A principal questão é demonstrar que os preceitos constitucionais e os direitos fundamentais são violados quando são negados aos LGBT o direito à vida, à dignidade e à segurança. Assim, será defendida a tese de que a proteção e a promoção dos direitos desse segmento específico da sociedade significa também um ganho geral para o exercício da cidadania.

  20. The presence of modifiable residues in the core peptide part of precursor nisin is not crucial for precursor nisin interactions with NisB- and NisC.

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    Rustem Khusainov

    Full Text Available Precursor nisin is a model posttranslationally modified precursor lantibiotic that can be structurally divided into a leader peptide sequence and a modifiable core peptide part. The nisin core peptide clearly plays an important role in the precursor nisin-nisin modification enzymes interactions, since it has previously been shown that the construct containing only the nisin leader sequence is not sufficient to pull-down the nisin modification enzymes NisB and NisC. Serines and threonines in the core peptide part are the residues that NisB specifically dehydrates, and cysteines are the residues that NisC stereospecifically couples to the dehydrated amino acids. Here, we demonstrate that increasing the number of negatively charged residues in the core peptide part of precursor nisin, which are absent in wild-type nisin, does not abolish binding of precursor nisin to the modification enzymes NisB and NisC, but dramatically decreases the antimicrobial potency of these nisin mutants. An unnatural precursor nisin variant lacking all serines and threonines in the core peptide part and an unnatural precursor nisin variant lacking all cysteines in the core peptide part still bind the nisin modification enzymes NisB and NisC, suggesting that these residues are not essential for direct interactions with the nisin modification enzymes NisB and NisC. These results are important for lantibiotic engineering studies.

  1. Neuronal migration during development and the amyloid precursor protein.

    Science.gov (United States)

    Copenhaver, Philip F; Ramaker, Jenna M

    2016-12-01

    The Amyloid Precursor Protein (APP) is the source of amyloid peptides that accumulate in Alzheimer's disease. However, members of the APP family are strongly expressed in the developing nervous systems of invertebrates and vertebrates, where they regulate neuronal guidance, synaptic remodeling, and injury responses. In contrast to mammals, insects express only one APP ortholog (APPL), simplifying investigations into its normal functions. Recent studies have shown that APPL regulates neuronal migration in the developing insect nervous system, analogous to the roles ascribed to APP family proteins in the mammalian cortex. The comparative simplicity of insect systems offers new opportunities for deciphering the signaling mechanisms by which this enigmatic class of proteins contributes to the formation and function of the nervous system. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Superhydrophobic Ceramic Coatings by Solution Precursor Plasma Spray

    Science.gov (United States)

    Cai, Yuxuan

    Superhydrophobic surfaces exhibit superior water repellent properties, and they have remarkable potential to improve current energy infrastructure. Substantial research has been performed on the production of superhydrophobic coatings. However, superhydrophobic coatings have not yet been adopted in many industries where potential applications exist due to the limited durability of the coating materials and the complex and costly fabrication processes. Here presented a novel coating technique to manufacture ceramic superhydrophobic coatings rapidly and economically. A rare earth oxide (REO) was selected as the coating material due to its hydrophobic nature and strong mechanical properties, and deposited on stainless steel substrates by solution precursor plasma spray (SPPS). The as-sprayed coating demonstrated a hierarchically structured coating topography, which closely resembles superhydrophobic surfaces in nature. Compared to smooth REO surfaces, the SPPS superhydrophobic coating improved the water contact angle by as much as 65° after vacuum treatment at 1 Pa for 48 hours.

  3. Review of Dolomite as Precursor of Geopolymer Materials

    Directory of Open Access Journals (Sweden)

    Azimi E.A.

    2016-01-01

    Full Text Available Geopolymer is an environmentally friendly cementitious binder that does not require the existence of ordinary Portland cement (OPC. Geopolymer has many excellent advantages, including high early strength, low shrinkage, good thermal resistance and good chemical resistance. Previous commonly used materials include fly ash, clay and slag. The used of dolomite as precursor material in geopolymer field is still new and at the early stage of study. Only a few researchers have done studies on dolomite in geopolymer. Dolomite (CaMg(CO32 is abundant and generally inexpensive natural minerals. The possible use of these bulk calcium carbonate materials in improving the mechanical properties of geopolymers will therefore be of great interest. This paper summarizes some research outcomes on dolomite in geopolymer along with the potential of dolomite as geopolymer composites.

  4. A primitive cell origin for B-cell precursor ALL?

    Science.gov (United States)

    Cox, C V; Blair, A

    2005-01-01

    A stem cell origin has been described for both acute and chronic myelogenous leukemias. In contrast, childhood B-cell precursor acute lymphoblastic leukemia (ALL) is thought to arise in committed B-lineage cells. Recently described in vitro and in vivo model systems that support the proliferation and expansion of ALL cells have provided new tools to investigate the cellular targets for the origin of this malignancy. Evidence suggests that some subtypes of childhood ALL have a primitive cell origin and share many immunophenotypic characteristics with normal progenitor cells. These leukemic stem cells may be resistant to current therapeutic strategies designed to kill the bulk ALL cell population and subsequent relapses may arise from this population. More precise definition of these ALL stem cells through combined analyses of antigen expression, genetic lesions, and functionality is essential for the development of more effective, targeted therapeutic strategies.

  5. Clinical and biological significance of precursor lesions ofintrahepatic cholangiocarcinoma

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Cholangiocarcinoma (CC) is primarily a malignant tumorof older adults most prevalent in Southeast Asia, whereliver fluke infestation is high. However the etiology inwestern countries is unknown. Although the incidence ofextrahepatic cholangiocarcinoma has remained constant,incidence of intrahepatic CC (ICC) which differs inmorphology, pathogenesis, risk factors, treatment andprognosis is increasing. While this increase is associatedwith hepatitis C virus infection, chronic nonalcoholicliver disease, obesity, and smoking, the pathogenesisof ICC and molecular alterations underlying the carcinogenesisare not completely elucidated. Benignbiliary lesions such as biliary intraepithelial neoplasia,intraductal papillary neoplasm of the bile duct, vonMeyenburg complex or bile duct hamartoma, and bileduct adenoma have been associated with ICC. For eachof these entities, evidence suggests or supports a roleas premalignant lesions. This article summarized theimportant biological significance of the precursor lesionsof ICC and the molecular mechanisms that may beinvolved in intrahepatic cholangiocarcinogenesis.

  6. Betaine suppressed Aβ generation by altering amyloid precursor protein processing.

    Science.gov (United States)

    Liu, Xiu-Ping; Qian, Xiang; Xie, Yue; Qi, Yan; Peng, Min-Feng; Zhan, Bi-Cui; Lou, Zheng-Qing

    2014-07-01

    Betaine was an endogenous catabolite of choline, which could be isolated from vegetables and marine products. Betaine could promote the metabolism of homocysteine in healthy subjects and was used for hyperlipidemia, coronary atherosclerosis, and fatty liver in clinic. Recent findings shown that Betaine rescued neuronal damage due to homocysteine induced Alzheimer's disease (AD) like pathological cascade, including tau hyperphosphorylation and amyloid-β (Aβ) deposition. Aβ was derived from amyloid precursor protein (APP) processing, and was a triggering factor for AD pathological onset. Here, we demonstrated that Betaine reduced Aβ levels by altering APP processing in N2a cells stably expressing Swedish mutant of APP. Betaine increased α-secretase activity, but decreased β-secretase activity. Our data indicate that Betaine might play a protective role in Aβ production.

  7. New Evaluation on the Preoxidation Extent of Different PAN Precursors

    Institute of Scientific and Technical Information of China (English)

    Wangxi ZHANG; Jie LIU; Jieying LIANG

    2004-01-01

    Structural changes in carbon fibers at each stage of, especially, preoxidation process are well known to play a great role in achieving the ultimate product quality. Differential scanning calorimetry (DSC), scanning electron microscope (SEM), density method and optical microscope were used to characterize the preoxidation extent. A conventional pproach, e.g., density aim, to evaluate the extent of preoxidation is not very exact. A DSC curve of a PAN precursor only can provide general information, major in the temperature regime of preoxidation reaction. However,the evaluation of a preoxidation extent, especially from conventional preoxidation temperature with a great span egime of 200~400℃, is put forward in this paper, in which the evolution of core/shell morphological structure is a kind of straightforward evidence.

  8. An Indian Ocean precursor for Indian summer monsoon rainfall variability

    Science.gov (United States)

    Sreejith, O. P.; Panickal, S.; Pai, S.; Rajeevan, M.

    2015-11-01

    The Indian summer monsoon rainfall (ISMR) depicts large interannual variability strongly linked with El Niño-Southern Oscillation (ENSO). However, many of the El Niño years were not accompanied by deficient ISMR. The results from the study reveal the significant role of coupled air-sea interaction over the tropical Indian Ocean (IO) in modifying the ENSO-ISMR association. The IO warm water volume (WWV), a measure of heat content variations in the equatorial IO has strong influence on ISMR. A deepening (shoaling) of thermocline in the eastern equatorial IO (EEIO) during late boreal spring (April-May) accompanied by increase (decrease) in WWV anomalies weaken (enhance) the ISMR by enhancing (suppressing) the convection over EEIO resulting in the below (above) normal ISMR. Thus, the changes in the WWV anomalies in the EEIO along with ENSO conditions during boreal spring can be considered as a precursor for the performance of subsequent ISMR.

  9. Multitopic ligand design: a concept for single-source precursors.

    Science.gov (United States)

    Gschwind, Fabienne; Sereda, Olha; Fromm, Katharina M

    2009-11-16

    The multitopic ligand O,O'-bisnicotinic acid tetraethylene glycol, L, was designed for the coordination of two distinct types of metal ions. In this work, we describe how the O-donor part of L is used to coordinate to alkaline earth metal ions and that the N-donor atoms of L bind to group 11 elements. This makes L a suitable ligand for the combination of both metal ion types within the same compound. This concept will be exemplified by highlighting the pure Ca(2+) complexes, a Cu(+)-coordination polymer network, as well as the mixed-metal compound, which can be used as a single-source precursor for mixed-metal oxide materials.

  10. Monocyte chemiluminescence and macrophage precursors in the aged.

    Directory of Open Access Journals (Sweden)

    Takahashi,Isao

    1985-12-01

    Full Text Available Age-related alterations in the host defense system have been vigorously investigated because of increased susceptibility to infection and neoplasms in the aged. Although monocyte-macrophages form a major part of the cellular defense against microorganisms, the majority of investigations has been limited to neutrophils and lymphocytes. The present study, designed to determine the influence of age on mononuclear phagocytes, revealed no significant decrease in the absolute number of blood monocytes, but did reveal a tendency for the chemiluminescence of blood monocytes to decrease (p less than 0.10 and a significant decrease in the numbers of macrophage precursors (p less than 0.05 in the aged (over 70 year old, in comparison with controls (under 40 years old. On the basis of these findings, functional alterations of monocyte-macrophages seem to participate in the increased susceptibility to infection in the aged.

  11. Hafnium carbide structural foams synthesized from polymer precursors

    Institute of Scientific and Technical Information of China (English)

    FAN Hai-bo; YANG Hong; N. K. RAVALA; H. C. WIKLE III; R. H. ZEE; B. A. CHIN

    2006-01-01

    Hafnium carbide (HfC) was applied in space and aerospace due to its ultra high melting temperature, high specific strength and moderate oxidation resistance. A novel synthesizing method was used to produce low density and high strength HfC structural foams through the thermolysis and pyrolysis of Hf containing polymer precursors (mixing of hafnium trifluoroacetylacetonate and epoxy) under vacuum atmosphere. The X-ray diffraction analysis shows that the produced foam is primarily composed of HfC containing 9%-10% HfO2. Several polymer powder compaction methods were used to improve the mechanical properties of HfC foam. Compression strengths of 200 MPa are achieved for HfC foams with density of 1.9 g/cm3 (total porosity about 85%). The proposed methodology of synthesizing HfC foam has the advantages of simple, inexpensive and less production time than alternate methods.

  12. Are saponins and sapogenins precursors of prednisolone? Preliminary results

    Directory of Open Access Journals (Sweden)

    Giuseppe Federico Labella

    2015-11-01

    Full Text Available The transformation of cortisol into prednisolone in cattle faeces was demonstrated and provided by literature, given the structural similarity of prednisolone with cortisol. In this study, we evaluated a possible neo-formation of prednisolone, as results of a faecal or environmental contamination. A saponine, α-solanine, and a sapogenin, diosgenin, were selected as possible precursors. A simple method without extraction was applied. The analyses were performed by HPLC–MSn to evaluate the possible transformations. The results showed that prednisolone was detected in the faecal suspension spiked with diosgenin at t= 8h, while cortisol was also detected at t = 24h in the sample of faeces spiked with α-solanine. In the feed and in the control samples, no transformations were observed.

  13. Synthesis of S-doped graphene by liquid precursor.

    Science.gov (United States)

    Gao, Hui; Liu, Zheng; Song, Li; Guo, Wenhua; Gao, Wei; Ci, Lijie; Rao, Amrita; Quan, Weijin; Vajtai, Robert; Ajayan, Pulickel M

    2012-07-11

    Doping is a common and effective approach to tailor semiconductor properties. Here, we demonstrate the growth of large-area sulfur (S)-doped graphene sheets on copper substrate via the chemical vapor deposition technique by using liquid organics (hexane in the presence of S) as the precursor. We found that S could be doped into graphene's lattice and mainly formed linear nanodomains, which was proved by elemental analysis, high resolution transmission microscopy and Raman spectra. Measurements on S-doped graphene field-effect transistors (G-FETs) revealed that S-doped graphene exhibited lower conductivity and distinctive p-type semiconductor properties compared with those of pristine graphene. Our approach has produced a new member in the family of graphene based materials and is promising for producing graphene based devices for multiple applications.

  14. Overview of the amorphous precursor phase strategy in biomineralization

    Institute of Scientific and Technical Information of China (English)

    Steve WEINER; Julia MAHAMID; Yael POLITI; Yurong MA; Lia ADDADI

    2009-01-01

    It was assumed for a long time that organisms produce minerals directly from a saturated solution. A few exceptions were known,including the well documented mineralized teeth of the chiton. In 1997 it was demon-stratedthat sea urchin larvae form their calcitic spicules by first depositing a highly unstable mineral phase called amorphous cualcium carbonate.This other phgyla has since been shown to be used by anlmals from other phyla and for both aragonita and calcite Recent evidence shows that vertebrate bone mineral may also be formed via a precursor phase of amorphous calcium carbonate. This strategy thus appears to be widespread The challenge now is to understand the mechanisms by which these unstable phases are initially formed,how they are temporarily stabilized and how they are destabilized and trans form into a crystalline mature product.

  15. Early precursors and enabling skills of reading acquisition.

    Science.gov (United States)

    Lundberg, Ingvar

    2009-12-01

    Research on early linguistic precursors and enabling skills of reading acquisition among young children is reviewed. Language development starts early in infancy when the child learns to categorize the speech sounds according to the pattern typical of the mother tongue. Equipped with these sound categories the child is ready to learn to segment words from the sound stream and to understand and to use words. The precise phonological representation of words will facilitate the important development of phonological awareness, a basic prerequisite for reading acquisition. This paper reviews some of my longitudinal research and training studies indicating the causal direction of the relation between phonological awareness and reading and includes some ongoing studies, where gender differences, socio-economic factors, dose-response-effects and motivational factors are explored. Preventive and remedial implications of the findings are pointed out. Finally, the complexity of the causal relationships between different aspects of early language development, including genetic influences and later reading is pointed out.

  16. Amyloid precursor protein is trafficked and secreted via synaptic vesicles.

    Directory of Open Access Journals (Sweden)

    Teja W Groemer

    Full Text Available A large body of evidence has implicated amyloid precursor protein (APP and its proteolytic derivatives as key players in the physiological context of neuronal synaptogenesis and synapse maintenance, as well as in the pathology of Alzheimer's Disease (AD. Although APP processing and release are known to occur in response to neuronal stimulation, the exact mechanism by which APP reaches the neuronal surface is unclear. We now demonstrate that a small but relevant number of synaptic vesicles contain APP, which can be released during neuronal activity, and most likely represent the major exocytic pathway of APP. This novel finding leads us to propose a revised model of presynaptic APP trafficking that reconciles existing knowledge on APP with our present understanding of vesicular release and recycling.

  17. Development of neural precursor cells from mouse embryonic stem cells

    Institute of Scientific and Technical Information of China (English)

    WU Xuan; LI Hai-di; Li Shu-nong; XU Hai-wei; XU Ling

    2001-01-01

    Objective: To explore the serum-free culture conditions for differentiating mouse embryonic stem cells (ES cells)into neural precursor cells (NPC) and compare the effects of human embryonic fibroblasts (HEF) as the feeder layer of ES with that of mouse embryonic fibroblasts (MEF)in vitro. Methods: Mouse ES cells were cultured in or not in feeder layer cells medium containing or not leukemia inhibitory factor to suppress their differentiation. Immunocytochemical method was used to identify NPC by detecting nestin antigen and alkaline phosphatase. Results: The ES cells cultured in HEF were positive to alkaline phosphatase. Serum-free medium allowed the differentiation of ES cells into NPC. Conclusion:HEF could replace MEF and keep the undifferentiated condition of ES cells with more benefits. NPC of high purity could be cultured from ES cells by serum-free culture method.

  18. C-type natriuretic peptide and its precursor

    DEFF Research Database (Denmark)

    Lippert, Solvej; Iversen, Peter; Brasso, Klaus;

    2015-01-01

    AIM: Seminal plasma offer a more organ-specific matrix for markers in prostatic disease. We hypothesized that C-type natriuretic peptide (CNP) expression may constitute such a new target. METHODS: Patients with benign prostatic hyperplasia, clinically localized and metastatic prostate cancer were...... examined for CNP and CNP precursor (proCNP) concentrations in blood and seminal plasma. Furthermore, CNP and the CNP receptor (NPR-B) mRNA contents in tissue from prostate and seminal vesicles were analyzed by qPCR. RESULTS: CNP and NPR-B concentrations decreased with increasing tumor burden (p = 0.......0027 and p = 0.0096, respectively). In contrast, seminal plasma CNP and proCNP concentrations were markedly increased with increased tumor burden (p prostate cancer....

  19. A METHOD DEVELOPED FOR PREDICTING POTENTIAL PRECURSORS OF EARTHQUAKES

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper describes the methodology used to eliminate environmental effects to a time series of short distance(24 m) leveling across a geological fault in order to detect potential precursors of earthquakes from the residual time series. First, linear trends and periodic signals are removed from the observations with the help of a recursive least squares method. Then, a controlled autoregression model is used to predict the enviromnental contribution due to precipitation and evaporation. The difference between the leveling data andthese predictions are considered to be due to endogenic crustal processes. Applying this methodology to leveling data of approximately 13 years at Niukouyu crustal deformation station near Beijing reveals an anomalous deformation before the Tangshan earthquake (M7.8),which has its epicenter about 180 km from the survey site. However, in the time period considered, another anomaly occurred which cannot be related directly to a seismic event.

  20. GUT precursors and fixed points in higher-dimensional theories

    Indian Academy of Sciences (India)

    Keith R Dienes; Emilian Dudas; Tony Gherghetta

    2004-02-01

    Within the context of traditional logarithmic grand unification at $M_{\\text{GUT}}≈ 10^{16}$ GeV, we show that it is nevertheless possible to observe certain GUT states such as $X$ and $Y$ gauge bosons at lower scales, perhaps even in the TeV range. We refer to such states as `GUT precursors'. Such states offer an interesting alternative possibility for new physics at the TeV scale, even when the scale of gauge coupling unification remains high, and suggest that it may be possible to probe GUT physics directly even within the context of high-scale gauge coupling unification. More generally, our results also suggest that it is possible to construct self-consistent `hybrid' models containing widely separated energy scales, and give rise to a Kaluza-Klein realization of non-trivial fixed points in higher-dimensional gauge theories.

  1. [Thyroid hormones and their precursors I. Biochemical properties].

    Science.gov (United States)

    Tóth, Gergo; Noszál, Béla

    2013-01-01

    This paper and the following one (see the next issue of Acta Pharmaceutica Hungarica) survey the biological roles and the related site-specific physico-chemical parameters (basicity and lipophilicity) of the presently known thyroid hormones (thyroxine, liothyronine and reverse liothyronine) and their biological precursors (monoiodotyrosine and diiodotyrosine). Here the literature of the thyroid hormone biochemistry, biosynthesis, plasma- and membrane transport is summarized, focusing on the pH-dependent processes. Biosyntheses of the thyroid hormones take place by oxidative coupling of two iodotyrosine residues catalyzed by thyreoperoxidase in thyreoglobulin. The protonation state of the precursors, especially that of the phenolic OH is crucial for the biosynthesis, since anionic iodotyrosine residues can only be coupled in the thyroid hormone biosyntheses. In the blood more than 99% of the circulating thyroid hormone is bound to plasma proteins among which the thyroxine-binding globulin and transthyretin are crucial. The amphiphilic character of the hormones is assumed to be the reason why their membrane transport is an energy-dependent, transport-mediated process, in which the organic anion transporter family, mainly OATP1C1, and the amino acid transporters, such as MCT8 play important roles. Liothyronine is the biologically active hormone; it binds the thyroid hormone receptor, a type of nuclear receptor. There are two major thyroid hormone receptor (TR) isoforms, alfa (TRalpha) and beta (TRbeta). The activation of the TRalpha is associated with modifications in cardiac behavior, while activation of the TRbeta is associated with increasing metabolic rates, resulting in weight loss and reduction of blood plasma lipid levels. The affinity of the thyroid hormones for different proteins depends on the ionization state of the ligands. The site-specific physico-chemical characterization of the thyroid hormones is of fundamental importance to understand their (patho

  2. Proconvertase proteolytic processing of an enzymatically active myeloperoxidase precursor.

    Science.gov (United States)

    McCormick, Sally; Nelson, Angela; Nauseef, William M

    2012-11-01

    Optimal and efficient killing of ingested microbes by human neutrophils is mediated in large part by the action of hypochlorous acid produced by the myeloperoxidase-H(2)O(2)-chloride system in phagosomes. Myeloperoxidase gene transcription is limited to early myeloid precursors in the bone marrow, when myeloperoxidase is synthesized and stored in azurophilic granules for subsequent release from stimulated neutrophils. Promyeloperoxidase, the 90 kDa myeloperoxidase precursor synthesized in the endoplasmic reticulum (ER), contains a 125-amino acid pro-region whose function and fate during myeloperoxidase biosynthesis are unknown. Promyeloperoxidase has two fates during myeloperoxidase biosynthesis; the majority undergoes proteolytic processing to generate mature myeloperoxidase, while the remainder is constitutively secreted from the cells in bone marrow. We used a promyelocytic cell line that produces endogenous myeloperoxidase as well as human embryonic kidney cells stably expressing normal and mutant forms of myeloperoxidase to examine proteolytic processing of promyeloperoxidase. We demonstrated that CMK-RVKR, an inhibitor of subtilisin-like proteinases, blocked cleavage of the pro-peptide of promyeloperoxidase in a post-ER compartment. Mutants with alanine substitution of basic residues in the predicted proteinase cleavage site failed to undergo maturation to normal myeloperoxidase subunits and were arrested at the promyeloperoxidase stage. Whereas specific mutants varied as to their stability, secreted promyeloperoxidase from the mutants retained the capacity to generate hypochlorous acid. Taken together, these studies demonstrate proconvertase-dependent cleavage of promyeloperoxidase as an essential step in normal proteolytic processing and granule targeting of myeloperoxidase. Furthermore, although mutations in the proteinase cleavage site reduced intracellular stability of the mutants, the integrity of the heme group was not compromised, as chlorinating

  3. Using Groundwater physiochemical properties for assessing potential earthquake precursor

    Science.gov (United States)

    Inbar, Nimrod; Reuveni, Yuval; Anker, Yaakov; Guttman, Joseph

    2017-04-01

    Worldwide studies reports pre-seismic, co-seismic and post-seismic reaction of groundwater to earthquakes. The unique hydrological and geological situation in Israel resulted in relatively deep water wells which are located close to seismically active tectonic plate boundary. Moreover, the Israeli experience show that anomalies may occurs 60-90 minutes prior to the seismic event (Guttman et al., 2005; Anker et al., 2016). Here, we try to assess the possible connection between changes in physiochemical parameters of groundwater and earthquakes along the Dead Sea Transform (DST) region. A designated network of monitoring stations was installed in MEKOROT abandoned deep water wells, continuously measuring water table, conductivity and temperature at a sampling rate of 1 minute. Preliminary analysis compares changes in the measured parameters with rain events, tidal effects and earthquake occurrences of all measured magnitudes (>2.5Md) at monitoring area surroundings. The acquired data set over one year recorded simultaneous abrupt changes in several wells which seems disconnected from standard hydrological occurrences such as precipitation, abstraction or tidal effects. At this stage, our research aims to determine and rationalize a baseline for "normal response" of the measured parameters to external occurrences while isolating those cases in which "deviations" from that base line is recorded. We apply several analysis techniques both in time and frequency domain with the measured signal as well as statistical analysis of several measured earthquake parameters, which indicate potential correlations between earthquakes occurrences and the measured signal. We show that at least in one seismic event (5.1 Md) a potential precursor may have been recorded. Reference: Anker, Y., N. Inbar, A. Y. Dror, Y. Reuveni, J. Guttman, A. Flexer, (2016). Groundwater response to ground movements, as a tool for earthquakes monitoring and a possible precursor. 8th International Conference

  4. Analysis of Amyloid Precursor Protein function in Drosophila melanogaster

    Directory of Open Access Journals (Sweden)

    Doris Kretzschmar

    2016-07-01

    Full Text Available The Amyloid precursor protein (APP has mainly been investigated in connection with its role in Alzheimer’s disease due to its cleavage resulting in the production of the Aβ peptides that accumulate in the plaques characteristic for this disease. However, APP is an evolutionary conserved protein that is not only found in humans but also in many other species, including Drosophila, suggesting an important physiological function. Besides Aβ, several other fragments are produced by the cleavage of APP; large secreted fragments derived from the N-terminus and a small intracellular C-terminal fragment. Although these fragments have received much less attention than Aβ, a picture about their function is finally emerging. In contrast to mammals, which express three APP family members, Drosophila expresses only one APP protein called Amyloid Precursor Protein-like or APPL. Therefore APPL functions can be studied in flies without the complication that other APP family members may have redundant functions. Flies lacking APPL are viable but show defects in neuronal outgrowth in the central and peripheral nervous system in addition to synaptic changes. Furthermore, APPL has been connected with axonal transport functions. In the adult nervous system, APPL, and more specifically its secreted fragments, can protect neurons from degeneration. APPL cleavage also prevents glial death. Lastly, APPL was found to be involved in behavioural deficits and in regulating sleep/activity patterns. This review, will describe the role of APPL in neuronal development and maintenance and briefly touch on its emerging function in circadian rhythms while an accompanying review will focus on its role in learning and memory formation.

  5. Micetoma pulmonar por Scedosporium sp, reporte de dos casos

    Directory of Open Access Journals (Sweden)

    José G. Somocurcio

    2009-07-01

    Full Text Available Se reporta los dos primeros casos de micetoma pulmonar por Scedosporium sp, en el Perú, tratados quirúrgicamente en el Hospital Nacional Hipólito Unanue. Se practicó resección pulmonar debido a micetoma pulmonar de donde se tomó muestras que fueron enviadas a microbiología y anatomía patológica para cultivo y estudio histopatológico. Se identificó el moho Scedosporium sp en dos pacientes con secuelas cavitarias por tuberculosis, quienes presentaron tos y hemoptisis de dos meses y tres años de evolución, respectivamente. Radiológicamente las cavidades estaban ocupadas por una "bola fúngica". La histopatología indicó presencia de abundantes hifas, indistinguibles de las de Aspergillus sp, mientras que la inmunodifusión para Aspergillus fue negativa.

  6. Independência dos auditores portugueses : o efeito cultural

    OpenAIRE

    Pinheiro, Bruno Miguel Braia

    2013-01-01

    Mestrado em Contabilidade, Fiscalidade e Finanças Empresariais Este estudo pretendeu analisar a importância dos factores que afectam a independência dos auditores (ou seja, as necessidades do investidor, retenção de clientes, valores e obrigações profissionais e pressões de tempo/orçamentárias), em dois cenários e em fase de realização dos trabalhos de auditoria. O primeiro cenário (caso 1) está relacionado com a pressão de tempo em face do prazo de entrega do relatório de auditoria, enqua...

  7. A administração dos cibertributos

    Directory of Open Access Journals (Sweden)

    Luis Carlos Cancellier de Olivo

    2000-01-01

    Full Text Available O presente trabalho identifica alguns procedimentos que ocorrem no ciberespaço, como atributação dos provedores de internet. Debate também o recolhimento do Imposto de Renda e do IPVA através da rede, bem como discute a extensão da imunidade ao livro eletrônico e ao ensino à distância. Indica como a União Européia está enfrentando a tributação dos negócios realizados via correio eletrônico. Situa, por fim, operadores jurídicos e administradores diante deste fenômeno da realidade digital, que é a existência dos cibertributos.

  8. Propriedades topológicas dos conjuntos de Julia

    OpenAIRE

    Uceda, Rafael Asmat [UNESP

    2008-01-01

    Seja f : C ! C uma fun»c~ao polinomial. O conjunto de Julia, J(f), associado a f, é o conjunto dos números complexos z onde a família ffng dos iterados de f não é normal em z. Neste trabalho, estudaremos varias propriedades topológicas de J(f). Calcularemos também a dimensão de Hausdor® de J(fc), onde fc(z) = z2+c e jcj é grande, e estudaremos as propriedades do conjunto de Mandelbrot associado a fc, isto é, o conjunto M dos números complexos pelos quais J(fc)é conexo. Em particular provaremo...

  9. The Unexpected Influence of Precursor Conversion Rate in the Synthesis of III-V Quantum Dots.

    Science.gov (United States)

    Franke, Daniel; Harris, Daniel K; Xie, Lisi; Jensen, Klavs F; Bawendi, Moungi G

    2015-11-23

    Control of quantum dot (QD) precursor chemistry has been expected to help improve the size control and uniformity of III-V QDs such as indium phosphide and indium arsenide. Indeed, experimental results for other QD systems are consistent with the theoretical prediction that the rate of precursor conversion is an important factor controlling QD size and size distribution. We synthesized and characterized the reactivity of a variety of group-V precursors in order to determine if precursor chemistry could be used to improve the quality of III-V QDs. Despite slowing down precursor conversion rate by multiple orders of magnitude, the less reactive precursors do not yield the expected increase in size and improvement in size distribution. This result disproves the widely accepted explanation for the shortcoming of current III-V QD syntheses and points to the need for a new generalizable theoretical picture for the mechanism of QD formation and growth.

  10. Analysis on responding ability of well-aquifer system to precursors

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shu-liang; LI Yuan-yuan; LI Dong-mei; FAN Xue-fang; ZHAO xiao-yun

    2006-01-01

    Recording number of precursors from fourteen observation wells in Shanxi, Hebei, Beijing and Jiangsu region is analyzed and percentage of recording number of precursors to total number of earthquakes during the statistic years is presented. The relationship between characteristic parameters of well-aquifer system and responding ability to precursors is analyzed by the expression of amplification factor of well-aquifer system induced by Cooper et al. The results indicate that responding ability of well-aquifer system to precursors is related to inherent period of well aquifer, that is to say, the greater the inherent period is, the stronger the ability of recording precursor is. Responding ability of well-aquifer system to precursors is also related to ratio of transmissivity to square of radius of wells, and the greater the ratio is, the stronger the responding ability is.

  11. Asymmetric synthesis of amino acid precursors in interstellar complex organics by circularly polarized light

    OpenAIRE

    Takano, Yoshinori; Takahashi, Jun-ichi; Kaneko, Takeo; Marumo, Katsumi; Kobayashi, Kensei

    2007-01-01

    The asymmetric synthesis of amino acid precursors from complex organics have been performed. A gaseous mixture of carbon monoxide, ammonia and water (molecules which are among those identified in the interstellar medium) was irradiated with 3.0 MeV protons to obtain amino acid precursors within high-molecular-weight complex organics of up to 3,000 Da. The amino acid precursor products synthesized were then irradiated with right (R-) or left (L-) ultraviolet circularly polarized light (UV-CPL)...

  12. Non-invasive method for in vivo detection of chlorophyll precursors

    DEFF Research Database (Denmark)

    Kristiansen, Kim Anker; Khrouchtchova, Anastassia; Stenbæk, Anne

    2009-01-01

    Traditionally chlorophyll (Chl) and Chl precursors have been studied in vitro or in leaf tissue at low temperature. These methods are destructive and make it impossible to work with the same individual plant later on. In this paper we present a method for in vivo detection of Chl and its precursors...... is compared to current methods. Furthermore, we report on optimization of the spectral scanning method with the aim to minimize the excitation light-evoked photo-conversion of the chlorophyll precursors....

  13. Method for Obtaining Committed Adult Mesenchymal Precursors from Skin and Lung Tissue

    OpenAIRE

    Aurora Bernal; María Fernández; Pérez, Laura M.; Nuria San Martín; Gálvez, Beatriz G.

    2012-01-01

    AIMS: The present study reports an easy and efficient method for obtaining adult mesenchymal precursors from different adult mouse tissues. MATERIALS AND METHODS: We describe the isolation and expansion of mesenchymal precursors from skin and lung by a non-enzymatic method. Skin and lung mesenchymal precursors isolated by a modified explant technique were characterized in vitro by defined morphology and by a specific gene expression profile and surface markers. RESULTS AND CONCLUSIONS: Our re...

  14. Monocephalus dipygus EN CACHARROS: REPORTE DE DOS CASOS

    Directory of Open Access Journals (Sweden)

    Teresa Oviedo S

    2008-12-01

    Full Text Available Se describen dos casos de duplicación posterior congénita en cachorros. Esta malformación también conocida como Monocephalus dipygus, hace referencia a individuos dobles, caracterizados por tener cabeza y tórax fusionados en uno solo, duplicidad simétrica de pelvis y miembros posteriores. El primer caso, presentó cuatro miembros anteriores, cuatro miembros posteriores y palatosquisis. El segundo caso, presentó dos miembros anteriores y cuatro miembros posteriores. En general, ambos casos pueden ser relacionados como gemelos fusionados simétricos.

  15. Valores pessoais dos consumidores de cafés especiais

    OpenAIRE

    Viana, Lílian Carolina

    2013-01-01

    O presente estudo trata da teoria de valores pessoais, passando pelas publicações no Brasil nos últimos anos em eventos e periódicos, realizando um estudo empírico na identificação dos valores pessoais de um nicho específico de consumidor: o de café especial. Tem como objetivo principal identificar teorias, autores e métodos das publicações no Brasil sobre valores pessoais na área de Marketing; e, identificar os valores pessoais dos consumidores de cafés especiais. Para tanto, esta dissertaçã...

  16. MANEJO COMUNITÁRIO: COMPLEXIDADE ALÉM DOS RECURSOS

    OpenAIRE

    Tourinho,Manoel Malheiros

    2008-01-01

    A teoria Geral dos Sistemas (Bertalanffy, 1968) e a Teoria dos Sistemas Sociais (Loomis, 1960) podem ser usadas para explicar as relações à nível das comunidades tradicionais na Amazônia entre as ciências sociais e as ciências naturais ou as relações do homem com a natureza, inclusive como decisões tomadas envolvem o uso de tecnologia para explorar os recursos naturais. O presente trabalho aclara essa relação e oferece as dimensões e variáveis que podem ser usadas em verificação empíricas, ta...

  17. Dos composiciones artificiosas de José de la Barrera

    OpenAIRE

    1989-01-01

    Además de la edición, contiene la traducción y comentario de estas dos composiciones en latín del predicador agustino fray José de la Barrera, que fue profesor de Filosofía en Sanlúcar de Barrameda en el siglo XVII. El primero consta de dos dísticos elegiacos y pertenece al género de los versus rapportati: cada uno de los cuatro versos consta de seis palabras pertenecientes a una misma categoría gramatical, y leído verticalmente, el poema consta de seis frases alusivas al santo de H...

  18. Contribution of N-Nitrosamines and Their Precursors to Domestic Sewage by Greywaters and Blackwaters.

    Science.gov (United States)

    Zeng, Teng; Mitch, William A

    2015-11-17

    N-nitrosamines and their precursors are significant concerns for water utilities exploiting wastewater-impacted water supplies, particularly those practicing potable reuse of wastewater. Previous efforts to identify specific precursors in municipal wastewater accounting for N-nitrosamine formation have met with limited success. As an alternative, we quantified the relative importance of greywater (i.e., shower, kitchen sink, bathroom washbasin, and laundry) and blackwater (i.e., urine and feces) streams in terms of their loadings of ambient specific and total N-nitrosamines and chloramine-reactive and ozone-reactive N-nitrosamine precursors to domestic sewage. Accounting for the volume fractions of individual greywater and blackwater streams, laundry water represented the most significant source of N-nitrosamines and their precursors, followed by shower water and urine. Laundry water was particularly important for ozone-reactive N-nitrosamine precursors, accounting for ∼99% of N-nitrosodimethylamine (NDMA) precursors and ∼69% of precursors for other uncharacterized N-nitrosamines. For the other greywater streams, consumer products contributed additional N-nitrosamines and precursors, but the remarkable uniformity across different products suggested the importance of common macroconstituents. The consumption of a standard dose of the antacid ranitidine substantially increased NDMA and its chloramine-reactive precursors in urine. Nevertheless, nearly 40% of the American population would need to consume ranitidine daily to match the NDMA loadings from laundry water.

  19. Cell-type dependent modulation of Notch signaling by the amyloid precursor protein

    National Research Council Canada - National Science Library

    Oh, Sun Young; Chen, Ci-Di; Abraham, Carmela R

    2010-01-01

    The amyloid precursor protein is a ubiquitously expressed transmembrane protein that has been long implicated in the pathogenesis of Alzheimer's disease but its normal biological function has remained...

  20. Cell-type dependent modulation of Notch signaling by the amyloid precursor protein.

    Science.gov (United States)

    Oh, Sun Young; Chen, Ci-Di; Abraham, Carmela R

    2010-04-01

    The amyloid precursor protein is a ubiquitously expressed transmembrane protein that has been long implicated in the pathogenesis of Alzheimer's disease but its normal biological function has remained elusive despite extensive effort. We have previously reported the identification of Notch2 as an amyloid precursor protein interacting protein in E18 rat neurons. Here, we sought to reveal the physiologic consequences of this interaction. We report a functional relationship between amyloid precursor protein and Notch1, which does not affect Delta ligand binding. First, we observed interactions between the amyloid precursor protein and Notch in mouse embryonic stem cells lacking both presenilin 1 and presenilin 2, the active proteolytic components of the gamma-secretase complex, suggesting that these two transmembrane proteins can interact in the absence of presenilin. Next, we demonstrated that the amyloid precursor protein affects Notch signaling by using Notch-dependent luciferase assays in two cell lines, the human embryonic kidney 293 and the monkey kidney, COS7. We found that the amyloid precursor protein exerts opposing effects on Notch signaling in human embryonic kidney 293 vs. COS7 cells. Finally, we show that more Notch Intracellular Domain is found in the nucleus in the presence of exogenous amyloid precursor protein or its intracellular domain, suggesting the mechanism by which the amyloid precursor protein affects Notch signaling in certain cells. Our results provide evidence of potentially important communications between the amyloid precursor protein and Notch.

  1. Controlled Growth of ZnSe Nanocrystals by Tuning Reactivity and Amount of Zinc Precursor

    Directory of Open Access Journals (Sweden)

    Lai-Jun Zhang

    2013-01-01

    Full Text Available Zinc selenide (ZnSe nanocrystals were synthesized via a phosphine-free route using the highly reactive alkylamine-H2Se complex as selenium precursor and zinc precursors with different reactivity. The reactivity of zinc precursor was tuned by using three kinds of zinc carboxylates with different alkyl chain lengths, including zinc acetate, zinc nonanoate, and zinc stearate. The effect of the reactivity and the amount of zinc precursor on nucleation and growth of ZnSe nanocrystals were investigated by ultraviolet-visible absorption and photoluminescence spectra. Result indicates that the growth and optical property of the resulting ZnSe nanocrystals are strongly dependent on the alkyl chain length and the amount of the zinc carboxylates and both shorter alkyl chain length, and more amount of zinc carboxylate will lead to faster growth of ZnSe nanocrystals. This allows that the controlled growth and excellent optical property of high-quality ZnSe nanocrystals can be achieved by combining the different reactivity and the used amount of zinc precursor, such as by using stoichiometric and reactive Zn precursor and Se precursor or by using larger amount of more unreactive Zn precursor relative to the highly reactive alkylamine-H2Se complex precursor.

  2. Optical precursor with four-wave mixing and storage based on a cold-atom ensemble.

    Science.gov (United States)

    Ding, Dong-Sheng; Jiang, Yun Kun; Zhang, Wei; Zhou, Zhi-Yuan; Shi, Bao-Sen; Guo, Guang-Can

    2015-03-06

    We observed optical precursors in four-wave mixing based on a cold-atom gas. Optical precursors appear at the edges of pulses of the generated optical field, and propagate through the atomic medium without absorption. Theoretical analysis suggests that these precursors correspond to high-frequency components of the signal pulse, which means the atoms cannot respond quickly to rapid changes in the electromagnetic field. In contrast, the low-frequency signal components are absorbed by the atoms during transmission. We also showed experimentally that the backward precursor can be stored using a Raman transition of the atomic ensemble and retrieved later.

  3. Synthesis of silicon carbide fiber using blend of polycarbosilane and hydroxy-terminated-polybutadiene as precursor

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Yiming; Yang, Shujin; Lu, Yi; Liu, Xinwei; Tan, Zilie (National Univ. of Defence Technology (China))

    1989-01-01

    SiC fiber was synthesized using a blend of polycarbosilane (PC) and the proper amount of hydroxy-terminated polybutadiene (HTPB) precursor. When the blend is used as a precursor to synthesize the SiC fiber, PC and HTPB will react to form a cross-linked polymer at about 260 C. So, less oxygen is needed in curing the precursor fiber, and less silicon dioxide is in the SiC fiber. The strength of SiC fiber is higher. Using the blend of PC and 3 wt pct HTPB as precursor, the strength of SiC fiber increases by about 26 percent.

  4. Enhanced optical precursors by Doppler effect via active Raman gain process.

    Science.gov (United States)

    Peng, Yandong; Niu, Yueping; Zhang, Lida; Yang, Aihong; Jiang, Lin; Gong, Shangqing

    2012-08-15

    A scheme for enhancing precursor pulse by Doppler effect is proposed in a room-temperature active-Raman-gain medium. Due to abnormal dispersion between two gain peaks, main fields are advanced and constructively interfere with optical precursors, which leads to enhancement of the transient pulse at the rise edge of the input. Moreover, after Doppler averaging, the abnormal dispersion intensifies and the constructive interference between precursors and main fields is much strengthened, which boosts the transient spike. Simulation results demonstrate that the peak intensity of precursors could be enhanced nearly 20 times larger than that of the input.

  5. Tissue engineering of corneal stroma with rabbit fibroblast precursors and gelatin hydrogels.

    Science.gov (United States)

    Mimura, Tatsuya; Amano, Shiro; Yokoo, Seiichi; Uchida, Saiko; Yamagami, Satoru; Usui, Tomohiko; Kimura, Yu; Tabata, Yasuhiko

    2008-01-01

    To isolate fibroblast precursors from rabbit corneal stroma using a sphere-forming assay, to engineer corneal stroma with the precursors and gelatin, and to establish the therapeutic application of precursors in a rabbit corneal stroma. In the in vitro study, a sphere-forming assay was performed to produce precursors from rabbit corneal stroma. Corneal stroma was engineered by cultivating precursors in porous gelatin for one week. In the in vivo study, the engineered corneal stromal sheet with precursors (precursor/gelatin group) or with fibroblasts (fibroblast /gelatin group) or without cells (gelatin group) was transplanted to a pocket of rabbit corneal stroma. Gene expression and extracellular matrix production were examined immunohistochemically in each group one week and four weeks after surgery. In the in vitro study, cells in the spheres were BrdU-positive, and their progeny were keratocan-positive. The study also showed that the corneas transplanted with a porous gelatin sheet did not show any opacity four weeks after transplantation in any group. In the gelatin sheet of the precursor/gelatin group, a more intense expression of type I collagen was observed relative to the other two groups four weeks after the surgery. Our findings demonstrate that the transplantation of fibroblast precursors combined with gelatin hydrogel into the corneal stroma is a possible treatment strategy for corneal stromal regeneration.

  6. O campo dos economistas franceses no fim dos anos 90: lutas de fronteira, autonomia e estrutura

    Directory of Open Access Journals (Sweden)

    Frédéric Lebaron

    2001-04-01

    Full Text Available A noção de economista, longe de simples e evidente, é objeto de numerosas lutas de definição. O exemplo do campo dos economistas franceses, analisado a partir de um conjunto de entrevistas, observações de dados prosopográficos, revela certas características dessas lutas. Estas opõem detendores de formas diferenciadas de capital, que estão elas mesmas em correspondência com posições distintas no campo do poder. Nessas lutas, estão em questão ao mesmo tempo a autonomia e a estrutura desse campo científico. A fraca autonomia relativa do campo da ciência econômica se faz acompanhar de uma forte homologia entre a estrutura desse campo e aquela do campo do poder francês em seu conjunto.The concept of the economist, rather than being a simple and evident one, is the object of numerous conflicting definitions. The example of the field of French economists, as analysed in a set of interviews and the observation of prospographical data, reveal certain characteristics of these conflicts. These struggles oppose those who detain differentiated forms of capital, which are themselves in correspondence with distinct positions in the field of power. These conflicts put into question both the autonomy and the structure of this scientific field. The relatively weak autonomy of the field of economical sciences is followed by a strong homology between the structure of this field and that of the field of French power in its entirety.

  7. Dos realidades: dos maneras de habitar conviven hoy en la ciudad

    Directory of Open Access Journals (Sweden)

    Carmen Faría Larrazábal

    2007-01-01

    Full Text Available Maracaibo, centro de explotación petrolera en Venezuela, desde el siglo XVII organizó su estructura urbana mediante la cuadrícula tradicional española, cuyo tejido presentaba un grano uniforme. La dinámica de crecimiento del siglo XX aportó configuraciones diferentes: las Villas Cerradas, las cuales incorporan paradigmas que dibujan un nuevo orden espacial. El trabajo aborda dos aspectos estrechamente vinculados: por un lado, la solución habitacional ofertada a grupos socioeconómicos de niveles medio y medio-alto, y por otro, cómo estos desarrollos establecen nuevos patrones en el quehacer urbano, y nuevos códigos y significados a la memoria colectiva de sus ciudadanos. Se revisa el statu quo de la acción planificadora y constructiva de la vivienda y se presentan nuevas experiencias realizadas en la década de los 90, las cuales a través de su arquitectura de grandes murallas expresan la autoprotección y el control disciplinario de las relaciones sociales. La investigación utiliza el análisis documental, planimétrico y la observación directa de los fenómenos urbanos como instrumentos de ayuda para dibujar los cambios producidos; lo cual será útil tanto para la comprensión de los procesos y su teorización crítica, como para la enseñanza, el ejercicio de la profesión y la planificación de la ciudad

  8. Descrição ultra - sonografica dos sistemas coletores dos rins em gestantes e em mulheres no puerperio imediato

    OpenAIRE

    Milton Bricola Filho

    1996-01-01

    Resumo: A dilatação dos sistemas coletores dos rins é freqüente durante a gestação, tendo como fatores etiológicos mais prováveis: a compressão do útero sobre os ureteres {teoria mecânica) e os níveis elevados de progesterona que promoveriam diminuição do peristaltismo e dilatação dos ureteres (teoria hormonal)- Apesar de se considerar este fenômeno como fisiológico, não se tem determinado na literatura os limites sobre os quais esta dilatação passaria a ser interpretada como patológica. Com ...

  9. A importância dos valores pessoais no funcionamento motivacional e no bem-estar dos professores

    OpenAIRE

    Cordeiro, Carla Patrícia Pereira Lousada dos Reis

    2016-01-01

    Dissertação de Mestrado, Psicologia da Educação, Faculdade de Ciências Humanas e Sociais, Universidade do Algarve, 2016 Neste estudo foi analisada a relação entre os valores pessoais e o comportamento motivacional dos professores no desempenho de tarefas específicas da atividade docente, e os efeitos destas variáveis nos níveis de bem-estar, à luz da Teoria da Autodeterminação (SDT) e da Teoria dos Valores Humanos de Schwartz. Participaram 345 professores do 2º e 3º Ciclo do Ensino Básico ...

  10. Caracterização epidemiológica dos microrganismos presentes em jalecos dos profissionais de saúde

    OpenAIRE

    Adriana Cristina de Oliveira; Marlene das Dores Medeiros Silva

    2013-01-01

    Estudo transversal cujo objetivo foi determinar as características epidemiológicas de microrganismos presentes nos jalecos de profissionais de saúde em um hospital universitário. A pesquisa foi realizada com profissionais de saúde, por meio da aplicação de um questionário para obtenção de informações quanto ao perfil sociodemográfico e comportamento dos profissionais da unidade de internação em relação aos cuidados com o jaleco. Em seguida, realizou-se a rolagem de swabs nas regiões dos bolso...

  11. O ENTENDIMENTO DOS ESTUDANTES DOS CURSOS TÉCNICOS DE ADMINISTRAÇÃO SOBRE AS ATIVIDADES REALIZADAS PELO MARKETING

    OpenAIRE

    Laeber, Izabel Maria; Mainardes, Emerson Wagner; Monte-mor, Danilo Soares

    2016-01-01

    Este estudo teve como objetivo avaliar a percepção dos estudantes dos cursos técnicos em Administração sobre o seu entendimento das atividades realizadas por um profissional de Marketing. O referencial teórico abrange conceitos sobre marketing, mix de marketing formado pelos 4 Ps (produto, preço, praça e promoção) e o ensino de marketing. No que se refere aos aspectos metodológicos, realizou-se um estudo de caráter descritivo e de natureza quantitativa, tendo como instrumento de coleta de dad...

  12. Application of a global proteomic approach to archival precursor lesions: deleted in malignant brain tumors 1 and tissue transglutaminase 2 are upregulated in pancreatic cancer precursors

    DEFF Research Database (Denmark)

    Cheung, Wang; Darfler, Marlene M; Alvarez, Hector;

    2008-01-01

    of invasive cancer. Biomarker discovery in precursor lesions has been hampered by the ready availability of fresh specimens, and limited yields of proteins suitable for large scale screening. METHODS: We utilized Liquid Tissue, a novel technique for protein extraction from archival formalin-fixed material...... their overexpression in IPMNs. CONCLUSION: Global proteomics analysis using the Liquid Tissue workflow is a feasible approach for unbiased biomarker discovery in limited archival material, particularly applicable to precursor lesions of cancer....

  13. Propostas para o estudo dos protestantismos ibéricos

    OpenAIRE

    Afonso, José António

    2004-01-01

    A propósito da edição da obra “Las minorias religiosas en España y Portugal: passado y presente”, número monográfico da revista “Anales de Historia Contemporanea” (Universidade de Múrcia), o Autor elenca algumas propostas para o estudo dos protestantismos ibéricos.

  14. Empreededorismo social: caso da 'cidade dos meninos' Belo Horizonte - Brasil

    Directory of Open Access Journals (Sweden)

    Walter Marinho de Oliveira

    2010-09-01

    Full Text Available A Cidade dos Meninos de São Vicente de Paulo, é uma das mais ousadas e completas abordagens no enfrentamento do problema dos menores de rua no Brasil. Este artigo, descreve a experiência da “Cidade dos Meninos” e de seu idealizador, apoiando-se em teorias recentes sobre empreendedorismo social. Atenção especial é dada à definição de empreendedor social catalítico (WADDOCK; POST, 1991, relacionando a atuação da liderança da Cidade dos Meninos a esse perfil. Uma das possíveis conclusões é que, em países em desenvolvimento como o Brasil, o empreendedor social catalítico não pode exercer apenas a função de criador e implementador de políticas, face a dimensão da carência e do problema com o qual ele se confronta, envolvendo-se então na ação direta

  15. Crítica do direito e teoria dos sistemas

    National Research Council Canada - National Science Library

    Möller, Kolja

    2015-01-01

    RESUMO O artigo centra-se em abordagens da teoria crítica do sistema em relação ao direito e à sociedade; mostra como elas modificam a estrutura da teoria ortodoxa dos sistemas e discute a forma...

  16. O número dos nomes em português

    Directory of Open Access Journals (Sweden)

    Clóvis Barleta de Morais

    2001-02-01

    Full Text Available

    Sistematização do estudo do número dos substantivos e adjetivos em português com base na pronúncia (fonologia, e não na ortografia, como se faz geralmente. Apresentação de listas de palavras que constituem exceções.

  17. Aprovechamiento en la escuela secundaria mexicana: dos intentos de mejora

    Directory of Open Access Journals (Sweden)

    Luis Felipe Gómez López

    2016-07-01

    Full Text Available El objetivo de este trabajo es dar cuenta del aprendizaje de los alumnos en la escuela secundaria mexicana y de dos intentos de mejora realizados por el autor debido a que los estudiantes de este nivel educativo muestran un bajo rendimiento en las competencias matemáticas y de comprensión lectora en las evaluaciones de PISA.

  18. Dos nuevas especies de Acalypha L. (Euphorbiaceae de Venezuela

    Directory of Open Access Journals (Sweden)

    Cardiel, José María

    1999-06-01

    Full Text Available Two new species of the genus Acalypha L. are described and illustrated, A. longipetiolata and A. venezuelica. Comments on the differences between these and related species are included.Se describen e ilustran dos nuevas especies del género Acalypha L., A. longipetiolata y A. venezuelica, descritas sobre material venezolano; se comentan las principales diferencias con las especies afines

  19. Emprego dos gangliosidos do cortex cerebral nas neuropatias perifericas

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    James Pitagoras De Mattos

    1981-12-01

    Full Text Available Os autores registram a experiência pessoal com o emprego de gangliosídios do cortex cerebral nas neuropatias periféricas. O ensaio clínico e eletromiográfico revelou-se eficaz em 30 dos 40 casos tratados. Enfatizam os melhores resultados em casos de paralisias faciais periféricas.

  20. A expectativa do professor e o desempenho dos alunos

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    Tufi Machado Soares

    Full Text Available Este trabalho enfoca dois aspectos fundamentais na interação professor-aluno: a sintonia entre o professor e sua turma, e a expectativa do professor quanto ao desempenho dos alunos. Cruzando-se informações de diferentes instrumentos contextuais, aplicados aos professores e alunos, com os resultados dos testes cognitivos dos alunos, pôde-se identificar os fatores que distorcem a percepção do professor acerca da turma e influenciam sua expectativa. Constatou-se que a expectativa do professor é influenciada por suas percepções em relação ao ambiente escolar e pelas características sociodemográficas dos alunos. Observou-se que a expectativa do professor provoca um impacto positivo na proficiência do aluno, mesmo considerando-se o efeito de variáveis sociodemográficas tradicionalmente associadas ao desempenho. Essas conclusões foram obtidas a partir da construção de modelos hierárquicos.

  1. Possible earthquake precursors revealed by LF radio signals

    Directory of Open Access Journals (Sweden)

    P. F. Biagi

    2001-01-01

    Full Text Available Among radio signals, low frequency (LF radio signals lie in the band between 30–300 kHz. Monitoring equipment with the ability to measure the electric strength of such signals at field sites, were designed and assembled in Italy. From 1993 onwards, the electric field strength of the MCO (216 kHz, France broadcasting station has been collecting measurements at two sites in central Italy that were chosen according to very low noise levels. At the end of 1996, radio signals from the CLT (189 kHz, Italy and CZE (270 kHz, Czech Republic broadcasting stations were included in the measurements. Meteorological data from central Italy were also collected over the same time period in order to study the influence of weather conditions on the experimental measurements. During the monitoring period, we observed some evident attenuation of the electric field strength in some of the radio signals at some of the receivers. The duration of the attenuation observed was several days, so it could possibly be related to particular meteorological conditions. On the other hand, this phenomenon might represent precursors of moderate (3.0 M 3.5 earthquakes that occurred near the receivers (within 50 km along the transmitter-receiver path. In this case, it is possible that the pre-seismic processes could have produced irregularities in the troposphere, such as ducts, reflecting layers and scattering zones, so that some local troposphere defocusing of the radio signals might have occurred. These observations were related only to moderate earthquakes and in these cases, suitable meteorological conditions were probably needed to observe the effect. Between February – March 1998, we observed at one measuring site, a significant increase in the CZE electric field strength. Unfortunately, we could not use the data of the other receiver in this case, due to frequent interruptions in the data set. The increase might have been a precursor of the strong seismic sequence (M = 5

  2. NASA Accident Precursor Analysis Handbook, Version 1.0

    Science.gov (United States)

    Groen, Frank; Everett, Chris; Hall, Anthony; Insley, Scott

    2011-01-01

    accident precursors by evaluating anomaly occurrences for their system safety implications and, through both analytical and deliberative methods used to project to other circumstances, identifying those that portend more serious consequences to come if effective corrective action is not taken. APA builds upon existing safety analysis processes currently in practice within NASA, leveraging their results to provide an improved understanding of overall system risk. As such, APA represents an important dimension of safety evaluation; as operational experience is acquired, precursor information is generated such that it can be fed back into system safety analyses to risk-inform safety improvements. Importantly, APA utilizes anomaly data to predict risk whereas standard reliability and PRA approaches utilize failure data which often is limited and rare.

  3. Electric earthquake precursors: from laboratory results to field observations.

    Science.gov (United States)

    Vallianatos, F.; Triantis, D.; Tzanis, A.; Anastasiadis, C.; Stavrakas, I.

    2003-04-01

    The possibility of electrical earthquake precursors (EEP) has long been appreciated, but it has proven difficult to construct a solid theory to describe their generation and expected characteristics, or proven techniques to identify and discriminate true precursors from noise. To this end, a large number of laboratory experiments have been conducted, which have demonstrated the generation of transient electric potential prior to rupture in both dry and wet rock specimens. The principal mechanisms proposed to explain these observations are the piezo-electric and electrokinetic effects. The often quoted in the literature piezoelectric effect, cannot explain why non-piezoelectric rock specimens can also generate precursory electric phenomena. Streaming potential can be generated in many kinds of saturated rocks, but the fracturing of dry rocks also produces transient electric effects. Therefore, these two mechanisms may not be the basic contributors to the precursory phenomena observed in the laboratory (and to possible EEP signals). Herein we present a series of laboratory experiments on the microfracturing electrification of dry marble samples under stress, and discuss their possible relationship to field observations of purported EEP. The marble samples were subjected to constant and variable stress-rate uniaxial compression, in both the elastic and the plastic region. During the experiment, pressure stimulated currents (PSC) were observed, which show a clear dependence on the stress rate and mechanical state of the material (the Young modulus), decreasing in frequency and intensity with increasing damage during repeated loading cycles. Explanation of these observations is attempted with a theoretical model involving microfracturing and the motion of charged edge dislocations (MCD) as the primary electrification mechanism, after Tzanis and Vallianatos (Seismo Electromagnetics: Lithosphere-Atmosphere-Ionosphere Coupling, TERRAPUB, 2002). The PSC waveforms and mode

  4. Synthesis of functional aromatic multisulfonyl chlorides and their masked precursors.

    Science.gov (United States)

    Percec, V; Bera, T K; De, B B; Sanai, Y; Smith, J; Holerca, M N; Barboiu, B; Grubbs, R B; Fréchet, J M

    2001-03-23

    The synthesis of functional aromatic bis(sulfonyl chlorides) containing an acetophenone and two sulfonyl chloride groups, i.e., 3,5-bis[4-(chlorosulfonyl)phenyl]-1-acetophenone (16), 3,5-bis(chlorosulfonyl)-1-acetophenone (17), and 3,5-bis(4-(chlorosulfonyl)phenyloxy)-1-acetophenone (18) via a sequence of reactions, involving in the last step the quantitative oxidative chlorination of S-(aryl)- N,N'-diethylthiocarbamate, alkyl- or benzyl thiophenyl groups as masked nonreactive precursors to sulfonyl chlorides is described. A related sequence of reactions was used for the synthesis of the aromatic trisulfonyl chloride 1,1,1-tris(4-chlorosulfonylphenyl)ethane (24). 4-(Chlorosulfonyl)phenoxyacetic acid, 2,2-bis[[[4-(chlorosulfonyl)phenoxyacetyl]oxy]methyl]-1,3-propanediyl ester (27), 5,11,17,23-tetrakis(chlorosulfonyl)-25,26,27,28-tetrakis(ethoxycarbonylmethoxy)calix[4]arene (38), 5,11,17,23,29,35-hexakis(chlorosulfonyl)-37,38,39,40,41,42-hexakis(ethoxycarbonylmethoxy)calix[6]arene (39), 5,11,17,23,29,35,41,47-octakis(chlorosulfonyl)-49,50,51,52,53,54,55,56-octakis(ethoxycarbonylmethoxy)calix[8]arene (40), 5,11,17,23-tetrakis(tert-butyl)-25,26,27,28-tetrakis(chlorosulfonyl phenoxyacetoxy)calix[4]arene (44), 5,11,17,23,29,35-hexakis(tert-butyl)-37,38,39,40,41,42-hexakis(chlorosulfonylphenoxyacetoxy)calix[6]arene (45), and 5,11,17,23,29,35,41,47-octakis(tert-butyl)-49,40,51,52,53,54,55,56-octakis(chlorosulfonylphenoxyacetoxy)calix[8]arene (46) were synthesized by two different multistep reaction procedures, the last step of both methods consisting of the chlorosulfonation of compounds containing suitable activated aromatic positions. 2,4,6-Tris(chlorosulfonyl)aniline (47) was obtained by the chlorosulfonation of aniline. The conformation of two series of multisulfonyl chlorides i.e., 38, 39, 40 and 44, 45, 46, was investigated by (1)H NMR spectroscopy. The masked nonreactive precursor states of the functional aromatic multisulfonyl chlorides and the aromatic

  5. Estudo dos elementos celulares na medula humana dos adultos I. linhagem plasmocitária

    Directory of Open Access Journals (Sweden)

    M. R. Q de Kastner

    1972-01-01

    Full Text Available Examinando o conjunto dos resultados obtidos nesta pesquisa e os dados pela literatura, observamos que o aumento numérico de células plasmáticas na medula óssea é um fenômeno relativamente freqüente. Todo hematologista habituado pode facilmente fazer o diagnóstico do estado da célula plasmocitária pela sua morfologia, seu tamanho e sua coloração. Nos quadros mais proeminentes de predominância de células de linhagem plasmocitária, os exames hematológicos e clínicos aliados ao mielograma, auxiliarão no diagnóstico do plasmocitoma. A nosso ver, os sinais (qualitativos, distintivos, de natureza citológica, que aparecem nos mielogramas no caso de plasmocitoma são: a Pleomorfismo e dismorfismo na célula plasmática; b "Rouleaux" de hemácias, já visível no hemograma; c Aumento das dimensões de alguns metamielócitos e bastonetes, acompanhados geralmente de atipias nucleares. Atipias e plurissegmentação nos segmentados; d No setor plaquetogenético aparecem plaquetas grandes e certo grau de perturbação nos megacarióticos, traduzido ás vezes pela presença de núcleos nus.Two hundred fifty bone marrow specimens, including twenty seven from hematologically normal patients, were examined hitologically. The Wright's and Brachet's stains were used. Plasma cells were rarely seen in the peripheral blood and bone marrow of normal individuals, but they were prominent constituents in some pathological states. A number significantly increased of plasma cells or mieloma cells were usually recognized in bone marrow from patients with plasmacytoma. These cells ranged from a very anaplastic immature form to closely resembling plasma cell. Even in the same patient, considerable pleomorphism often occured, and variation in cell size, number of nuclei and degree of nuclear immaturity were common. Although the results report certain observations regarding to the other cell series in patients with plasmacytoma. The most suggestive evidences

  6. Ação dos sucos digestivos sobre a absorção e destino do bcg Oral

    Directory of Open Access Journals (Sweden)

    Rodnei C. Mortatti

    1986-12-01

    Full Text Available Estudou-se a ação do suco gástrico artificial e suco duodenal humano sobre a vacina BCG, bem como a absorção e destino desta após administração intragástrica em camundongos. O contato de 2 horas do bacilo com o suco gástrico provocou uma diminuição significante do consumo de oxigênio e uma moderada perda da viabilidade. O suco duodenal induziu marcante decréscimo da respiração bacilar egrande redução da viabilidade. O BCG foi marcado com carbono-14 usando-se 14C-glicerol como precursor dos lipidios micobacterianos. Níveis similares de radioatividade foram obtidos nos órgãos dos animais, 24 horas após administração intragástrica de 14C- BCG, 14C-BCG rompido por ultra-som e 14C-glicerol. Os níveis de 14C-BCG permaneceram estáveis do 6º ao 24º dia, enquanto o sonicado de 14C-BCG e 14C-glicerol definiram um processo de decaimento biológico. As curvas de biodecaimento no intestino delgado e no fígado indicaram que o processo de absorção foi desencadeado rapidamente e alcançou seu nível máximo às 24 horas, decaindo em seguida de acordo com a complexidade química do material dado aos camundongos. Não foram isolados bacilos viáveis dos órgãos dos animais que receberam BCG não marcado. Pode-se concluir, portanto, que a maioria dos bacilos foram absorvidos intactos mas não viáveis.The absorption and the biological routing of Mycobacterium bovis BCG vaccine following intragastric administration to mice was studied. A harmful action of gastric (GJ and duodenal juices (DJ on BCG cells in vitro was found. Treatment with GJ induced a significant decrease of the oxygen uptake and a moderate loss of viability, as expressed by the number of colony-forming units (CFU of BCG. Severe decreases of bacilli respiration and a notable fali of CFU counts were detected during DJ treatment. The biorouting of BCG cells was determined using carbon-14 labelled bacilli. The labelling was accomplished through a metabolic precursor of

  7. The petrochemistry of the auriferous, volcanosedimentary Riacho dos Machados Group, Central-eastern Brazil: geotectonic implications for shear-hosted gold mineralization

    Science.gov (United States)

    da Fonseca, E.; Lobato, L. M.; Baars, F. J.

    1997-12-01

    The Ouro Fino Gold Deposit at the Riacho dos Machados Mine is located in the Araçuaí Fold Belt at the eastern margin of the São Francisco Craton. The gold is shear zone-hosted and associated principally with a sulphide-bearing, quartzmuscovite schist, derived from the hydrothermal alteration of pelitic and quartzofeldspathic schists of the Riacho dos Machados Group (RMG). Along the shear zones, mineral associations typical of the amphibolite facies are progressively altered to assemblages typical of the greenschist facies. It has become evident from the studies that the process of segregation and concentration of chemical elements and minerals is the very process of mineralization, involving the concentration of Au. The RMG comprises ultramafic, mafic and acid metavolcanic rocks intercalated in a sequence of metapelites. The metapelites have textures and geochemistry compatible with greywackes. The dacitic and mafic/ultramafic rocks are of calc-alkaline and tholeiitic subalkaline association, respectively. The RMG probably formed within a continental volcanic arc. The thrust faults that establish the regional architecture, and which host the Riacho dos Machados gold mineralization, are related to a continental collision of unknown age between the precursor to the São Francisco Craton and the Guanambi-Correntina Block.

  8. Dinâmica dos micronutrientes em cafeeiros enxertados

    Directory of Open Access Journals (Sweden)

    André Dominghetti Ferreira

    2013-04-01

    Full Text Available As respostas à disponibilidade dos nutrientes variam entre espécies distintas dentro de um mesmo gênero, por causa, principalmente, das exigências nutricionais variáveis, capacidade de absorção, translocação e utilização dos nutrientes. O objetivo deste trabalho foi avaliar a eficiência de absorção, translocação e uso dos micronutrientes por diferentes cultivares de Coffea arabica L., enxertados em Apoatã IAC 2258 (Coffea canephora. O experimento foi instalado em casa de vegetação, utilizando-se o método de cultivo em solução nutritiva. Foi utilizado um fatorial 7 x 3 + 2, sendo sete cultivares de Coffea arabica L. (Palma II, Catucaí 2 SL, Oeiras MG 6851, Obatã IAC 1669-20, Acauã, Topázio MG 1190 e Paraíso MG H 419-1, três tipos de mudas (pé franco, autoenxertada e enxertada sobre o cultivar Apoatã IAC 2258 e duas testemunhas (Apoatã autoenxertado e Apoatã pé franco. O porta-enxerto utilizado influenciou negativamente na absorção de boro, ferro e manganês. A translocação dos micronutrientes boro e cobre obteve maiores índices nas mudas enxertadas. O cultivar Palma II, quando enxertado, apresentou o maior índice de utilização dos nutrientes, mostrando-se passível de ser enxertado. O porta-enxerto utilizado mostrou-se apto para a enxertia, por não sofrer influência negativa, tanto pela enxertia, quanto pelos cultivares utilizados.

  9. Manejo dos portadores das neoplasias intraepiteliais anais Managment of anal intra-epithelial neoplasia patients

    Directory of Open Access Journals (Sweden)

    Sidney Roberto Nadal

    2008-12-01

    Full Text Available Acredita-se que a neoplasia intraepitelial anal (NIA, provocada pelo HPV, seja a lesão precursora do carcinoma anal. Segundo a literatura, são encontradas entre 11% e 52% dos homens infectados pelo HIV, entre 6% a 20% dos homens e 1% a 2,8% das mulheres sem essa infecção. Entre 8,5% e 13% das NIA de alto grau evoluirão para carcinoma invasivo, indicando a necessidade do rastreamento e do seguimento desses doentes para prevenção. Não há tratamento satisfatório com baixos índices de morbidez e a recidiva é comum. Em geral, as formas de tratamento podem de ser divididas em tópicas, entre elas, ácido tricloroacético, podofilina, podofilotoxina, imiquimod, terapia fotodinâmica, e ablativas, ou seja, excisão cirúrgica, ablação pelo LASER, coagulação pelo infravermelho e eletrofulguração. Há, ainda, os que consideram aceitável a conduta expectante. O tratamento tópico se justifica pelo caráter multifocal da lesão e os ablativos têm taxas de complicação e recidiva muito semelhantes. De qualquer forma, doentes com qualquer anormalidade histológica necessitam de seguimento adequado, principalmente com colposcopia e citologia anal.Anal intra-epithelial neoplasia (AIN, provoked by HPV, is considered as an anal cancer precursor. Some articles noticed that it occurred among 11% and 52% of men who have sex with men (MSM infected with HIV and, among seronegatives, from 6% to 20% of men and from 1% to 2.8% of women. From 8.5% to 13% of high grade AIN will evolve to invasive carcinoma, needing follow-up and screening for prevention. There is no satisfactory treatment with low morbidity and recurrence is frequent. There are two main forms of treatment: topics (trichloroacetic acid, podophylin, podophylotoxin, imiquimod, photodynamic therapy and ablatives (chirurgical excision, LASER, infrared, eletrocautery. Others consider acceptable an expectant management. Topical therapy is justified because of multifocal presentation of HPV

  10. Isolation of Some Glucosides as Aroma Precursors from Ginger.

    Science.gov (United States)

    Sekiwa, Y; Mizuno, Y; Yamamoto, Y; Kubota, K; Kobayashi, A; Koshino, H

    1999-01-01

    A glycosidically bound fraction was prepared by adsorbing a 80% methanol extract from fresh rhizomes of ginger onto a column of Amberlite XAD-2 resin and successively eluting with ethyl acetate or methanol. Enzymatic hydrolysis of this fraction with an acetone powder prepared from fresh ginger and commercial glycosidase liberated such alcohols as geraniol, 2-heptanol, α-terpineol, nerol, linalool, and citronellol, suggesting that fresh ginger included glycosides and glycosidase. The ethyl acetate eluate was chromatographed by an ODS flash column and then HPLC to isolate the β-glucopyranosides of 5-hydroxyborneol, 1,8-epoxy-p-menthan-3-ol, (2E, 6E)- and (2E, 6Z)-3,7-dimethyl-8-hydroxyoctadien-1-ol, 2-heptanol, geraniol, nerol, (R)-linalool, and citronellol. All the glucosides, except for 5-hydroxybornyl-O-β-D-glucopyranoside, were identified for the first time in the rhizome of ginger, and many of their aglycons were major constituents of the essential oil. The results indicate that these glucosides are aroma precursors of fresh ginger.

  11. ISRO's dual frequency airborne SAR pre-cursor to NISAR

    Science.gov (United States)

    Ramanujam, V. Manavala; Suneela, T. J. V. D.; Bhan, Rakesh

    2016-05-01

    The Indian Space Research Organisation (ISRO) and the National Aeronautics and Space Administration (NASA) have jointly embarked on NASA-ISRO Synthetic Aperture Radar (NISAR) operating in L-band and S-band, which will map Earth's surface every 12 days. As a pre-cursor to the NISAR mission, ISRO is planning an airborne SAR (L&S band) which will deliver NISAR analogue data products to the science community. ISRO will develop all the hardware with the aim of adhering to system design aspects of NISAR to the maximum extent possible. It is a fully polarimetric stripmap SAR and can be operated in single, dual, compact, quasi-quad and full polarimetry modes. It has wide incidence angle coverage from 24°-77° with swath coverage from 5.5km to 15 km. Apart from simultaneous imaging operations, this system can also operate in standalone L/S SAR modes. This system is planned to operate from an aircraft platform with nominal altitude of 8000meters. Antenna for this SAR will be rigidly mounted to the aircraft, whereas, motion compensation will be implemented in the software processor to generate data products. Data products for this airborne SAR will be generated in slant & ground range azimuth dimension and geocoded in HDF5/Geotiff formats. This airborne SAR will help to prepare the Indian scientific community for optimum utilization of NISAR data. In-order to collect useful science data, airborne campaigns are planned from end of 2016 onwards.

  12. Defining the cellular precursors to human breast cancer

    Science.gov (United States)

    Keller, Patricia J.; Arendt, Lisa M.; Skibinski, Adam; Logvinenko, Tanya; Klebba, Ina; Dong, Shumin; Smith, Avi E.; Prat, Aleix; Perou, Charles M.; Gilmore, Hannah; Schnitt, Stuart; Naber, Stephen P.; Garlick, Jonathan A.; Kuperwasser, Charlotte

    2012-01-01

    Human breast cancers are broadly classified based on their gene-expression profiles into luminal- and basal-type tumors. These two major tumor subtypes express markers corresponding to the major differentiation states of epithelial cells in the breast: luminal (EpCAM+) and basal/myoepithelial (CD10+). However, there are also rare types of breast cancers, such as metaplastic carcinomas, where tumor cells exhibit features of alternate cell types that no longer resemble breast epithelium. Until now, it has been difficult to identify the cell type(s) in the human breast that gives rise to these various forms of breast cancer. Here we report that transformation of EpCAM+ epithelial cells results in the formation of common forms of human breast cancer, including estrogen receptor-positive and estrogen receptor-negative tumors with luminal and basal-like characteristics, respectively, whereas transformation of CD10+ cells results in the development of rare metaplastic tumors reminiscent of the claudin-low subtype. We also demonstrate the existence of CD10+ breast cells with metaplastic traits that can give rise to skin and epidermal tissues. Furthermore, we show that the development of metaplastic breast cancer is attributable, in part, to the transformation of these metaplastic breast epithelial cells. These findings identify normal cellular precursors to human breast cancers and reveal the existence of a population of cells with epidermal progenitor activity within adult human breast tissues. PMID:21940501

  13. Liquid precursor films spreading on chemically patterned substrates

    Science.gov (United States)

    Checco, Antonio

    2008-03-01

    We study the spreading of nonvolatile liquid squalane on chemically patterned nanostripes by using non-contact Atomic Force Microscopy (NC-AFM). The substrates are octadecylthrichlorosilane(OTS)-coated silicon wafers chemically patterned on multiple length-scales using a combination of UV and AFM oxidative lithographies. This process allows us to locally convert the terminal methyl groups of the OTS surface (non-wettable) into carboxylic acid groups (wettable) without affecting considerably the substrate roughness (squalane spreads across this ``microfluidic network'' starting from the large lines eventually reaching the nanolines (50 to 500 nm-wide). NC-AFM is used to image the morphology of the liquid as it spreads across the nanolines. We find that the liquid thickness on the nanolines grows with time (up to ˜10 nm) according to a power-law with exponent ˜1. These preliminary results suggest that the spreading dynamics of laterally-confined liquids slightly differs, as expected, from the one of laterally homogeneous precursor films. We compare our findings to recent theoretical predictions of confined liquid flow and also discuss its relevance to nanofluidics.

  14. LISA and its in-flight test precursor SMART-2

    Energy Technology Data Exchange (ETDEWEB)

    Vitale, S.; Bender, P.; Brillet, A.; Buchman, S.; Cavalleri, A.; Cerdonio, M.; Cruise, M.; Cutler, C.; Danzmann, K.; Dolesi, R.; Folkner, W.; Gianolio, A.; Jafry, Y.; Hasinger, G.; Heinzel, G.; Hogan, C.; Hueller, M.; Hough, J.; Phinney, S.; Prince, T.; Richstone, D.; Robertson, D.; Rodrigues, M.; Ruediger, A.; Sandford, M.; Schilling, R.; Shoemaker, D.; Schutz, B.; Stebbins, R.; Stubbs, C.; Sumner, T.; Thorne, K.; Tinto, M.; Touboul, P.; Ward, H.; Weber, W.; Winkler, W

    2002-07-01

    LISA will be the first space-home gravitational wave observatory. It aims to detect gravitational waves in the 0.1 mHz/1 Hz range from sources including galactic binaries, super-massive black-hole binaries, capture of objects by super-massive black-holes and stochastic background. LISA is an ESA approved Cornerstone Mission foreseen as a joint ESA-NASA endeavour to be launched in 2010-11. The principle of operation of LISA is based on laser ranging of test-masses under pure geodesic motion. Achieving pure geodesic motion at the level requested for LISA, 3x10{sup -15} ms{sup -2}/{radical}Hz at 0.1 mHz, is considered a challenging technological objective. To reduce the risk, both ESA and NASA are pursuing an in-flight test of the relevant technology. The goal of the test is to demonstrate geodetic motion within one order of magnitude from the LISA performance. ESA has given this test as the primary goal of its technology dedicated mission SMART-2 with a launch in 2006. This paper describes the basics of LISA, its key technologies, and its in-flight precursor test on SMART-2.

  15. Functional integration of human neural precursor cells in mouse cortex.

    Directory of Open Access Journals (Sweden)

    Fu-Wen Zhou

    Full Text Available This study investigates the electrophysiological properties and functional integration of different phenotypes of transplanted human neural precursor cells (hNPCs in immunodeficient NSG mice. Postnatal day 2 mice received unilateral injections of 100,000 GFP+ hNPCs into the right parietal cortex. Eight weeks after transplantation, 1.21% of transplanted hNPCs survived. In these hNPCs, parvalbumin (PV-, calretinin (CR-, somatostatin (SS-positive inhibitory interneurons and excitatory pyramidal neurons were confirmed electrophysiologically and histologically. All GFP+ hNPCs were immunoreactive with anti-human specific nuclear protein. The proportions of PV-, CR-, and SS-positive cells among GFP+ cells were 35.5%, 15.7%, and 17.1%, respectively; around 15% of GFP+ cells were identified as pyramidal neurons. Those electrophysiologically and histological identified GFP+ hNPCs were shown to fire action potentials with the appropriate firing patterns for different classes of neurons and to display spontaneous excitatory and inhibitory postsynaptic currents (sEPSCs and sIPSCs. The amplitude, frequency and kinetic properties of sEPSCs and sIPSCs in different types of hNPCs were comparable to host cells of the same type. In conclusion, GFP+ hNPCs produce neurons that are competent to integrate functionally into host neocortical neuronal networks. This provides promising data on the potential for hNPCs to serve as therapeutic agents in neurological diseases with abnormal neuronal circuitry such as epilepsy.

  16. Dynamic Precursors of Flares in Active Region NOAA 10486

    Indian Academy of Sciences (India)

    M. B. Korsós; N. Gyenge; T. Baranyi; A. Ludmány

    2015-03-01

    Four different methods are applied here to study the precursors of flare activity in the Active Region NOAA 10486. Two approaches track the temporal behaviour of suitably chosen features (one, the weighted horizontal gradient WGM, is the generalized form of the horizontal gradient of the magnetic field, GM; the other is the sum of the horizontal gradient of the magnetic field, GS, for all sunspot pairs). WGM is a photospheric indicator, that is a proxy measure of magnetic non-potentiality of a specific area of the active region, i.e., it captures the temporal variation of the weighted horizontal gradient of magnetic flux summed up for the region where opposite magnetic polarities are highly mixed. The third one, referred to as the separateness parameter, Sl−f, considers the overall morphology. Further, GS and Sl−f are photospheric, newly defined quick-look indicators of the polarity mix of the entire active region. The fourth method is tracking the temporal variation of small X-ray flares, their times of succession and their energies observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager instrument. All approaches yield specific pre-cursory signatures for the imminence of flares.

  17. Preparation of cuxinygazsen precursor films and powders by electroless deposition

    Science.gov (United States)

    Bhattacharya, Raghu N.; Batchelor, Wendi Kay; Wiesner, Holm; Ramanathan, Kannan; Noufi, Rommel

    1999-01-01

    A method for electroless deposition of Cu.sub.x In.sub.y Ga.sub.z Se.sub.n (x=0-2, y=0-2, z=0-2, n=0-3) precursor films and powders onto a metallic substrate comprising: preparing an aqueous bath solution of compounds selected from the group consisting of: I) a copper compound, a selenium compound, an indium compound and gallium compound; II) a copper compound, a selenium compound and an indium compound; III) a selenium compound, and indium compound and a gallium compound; IV) a selenium compound and a indium compound; and V) a copper compound and selenium compound; each compound being present in sufficient quantity to react with each other to produce Cu.sub.x In.sub.y Ga.sub.z Se.sub.n (x=0-2, y=0-2, z=0-2, n=0-3); adjusting the pH of the aqueous bath solution to an acidic value by the addition of a dilute acid; and initiating an electroless reaction with an oxidizing counterelectrode for a sufficient time to cause a deposit of Cu.sub.x In.sub.y Ga.sub.z Se.sub.n (x=0-2, y=0-2, z=0-2, n=0-3) from the aqueous bath solution onto a metallic substrate.

  18. Comparative investigation of B-Protein and its probable precursor

    Energy Technology Data Exchange (ETDEWEB)

    Schweikert, A.; Bucovaz, E.

    1987-05-01

    B-Protein, discovered in 1976 by Bucovaz, appears to be a general biological marker for the detection of cancer. An assay procedure was developed to detect B-Protein which involves the interaction of B-Protein with a specific radiolabeled protein named binding protein, a substructure of the coenzyme A-synthesizing protein complex (CoA-SPC) of Bakers' yeast. A protein which may be the precursor of B-Protein is present normally in serum, whereas, a modified or altered protein, designated B-Protein, is present in the serum of cancer patients. Analysis of B-Protein and its relationship with the normal serum protein demonstrates a difference in solubility between B-Protein and the normal counterpart. Although physiochemical characteristics between both are very similar, i.e., electrophoretic mobility, molecular weight, pI, immunological recognition, there appears to be minor differences in the carbohydrate moiety of B-Protein as demonstrated by periodic acid-Schiff base staining and the binding of Wheat Germ Lectin. Lipid content has also been examined but has not been associated with the difference in solubility. Currently, the difference in B-Protein and its normal protein counterpart appears to be related to conformational differences in the tertiary structures.

  19. Synthesis of 9-oxononanoic acid, a precursor for biopolymers.

    Science.gov (United States)

    Otte, Konrad B; Kirtz, Marko; Nestl, Bettina M; Hauer, Bernhard

    2013-11-01

    Polymers based on renewable resources have become increasingly important. The natural functionalization of fats and oils enables an easy access to interesting monomeric building blocks, which in turn transform the derivative biopolymers into high-performance materials. Unfortunately, interesting building blocks of medium-chain length are difficult to obtain by traditional chemical means. Herein, a biotechnological pathway is established that could provide an environmentally suitable and sustainable alternative. A multiple enzyme two-step one-pot process efficiently catalyzed by a coupled 9S-lipoxygenase (St-LOX1, Solanum tuberosum) and 9/13-hydroperoxide lyase (Cm-9/13HPL, Cucumis melo) cascade reaction is proposed as a potential route for the conversion of linoleic acid into 9-oxononanoic acid, which is a precursor for biopolymers. Lipoxygenase catalyzes the insertion of oxygen into linoleic acid through a radical mechanism to give 9S-hydroperoxy-octadecadienoic acid (9S-HPODE) as a cascade intermediate, which is subsequently cleaved by the action of Cm-9/13HPL. This one-pot process afforded a yield of 73 % combined with high selectivity. The best reaction performance was achieved when lipoxygenase and hydroperoxide lyase were applied in a successive rather than a simultaneous manner. Green leaf volatiles, which are desired flavor and fragrance products, are formed as by-products in this reaction cascade. Furthermore, we have investigated the enantioselectivity of 9/13-HPLs, which exhibited a strong preference for 9S-HPODE over 9R-HPODE.

  20. Glass precursor approach to high-temperature superconductors

    Science.gov (United States)

    Bansal, Narottam P.

    1992-01-01

    The available studies on the synthesis of high T sub c superconductors (HTS) via the glass precursor approach were reviewed. Melts of the Bi-Sr-Ca-Cu-O system as well as those doped with oxides of some other elements (Pb, Al, V, Te, Nb, etc.) could be quenched into glasses which, on further heat treatments under appropriate conditions, crystallized into the superconducting phase(s). The nature of the HTS phase(s) formed depends on the annealing temperature, time, atmosphere, and the cooling rate and also on the glass composition. Long term annealing was needed to obtain a large fraction of the 110 K phase. The high T sub c phase did not crystallize out directly from the glass matrix, but was preceded by the precipitation of other phases. The 110 K HTS was produced at high temperatures by reaction between the phases formed at lower temperatures resulting in multiphase material. The presence of a glass former such as B2O3 was necessary for the Y-Ba-Cu-O melt to form a glass on fast cooling. A discontinuous YBa2Cu3O(7-delta) HTS phase crystallized out on heat treatment of this glass. Attempts to prepare Tl-Ba-Ca-Cu-O system in the glassy state were not successful.

  1. Pathways to adulthood and their precursors and outcomes.

    Science.gov (United States)

    Skogbrott Birkeland, Marianne; Leversen, Ingrid; Torsheim, Torbjørn; Wold, Bente

    2014-02-01

    Norway has an extensive welfare system which may provide adolescents with many options and high levels of flexibility in terms of pathways to adulthood. This study aimed to describe Norwegian developmental pathways to adulthood, including changes in role statuses (such as living situations, education, work, marriage/cohabitation and parenthood) from 16 to 30 years of age, and their precursors and outcomes. Repeated measures latent class analysis of longitudinal data from 998 Norwegian individuals indicated three main pathways to adulthood among women and men. In both sexes, most individuals undertook a long period of education and postponed family formation. However, some individuals started working early, a group of women established families with partners and children early, and a group of men remained primarily single between 16 and 30 years of age. Furthermore, the results show that pathways to adulthood in Norway are surprisingly similar to pathways in other countries such as the US, UK and Finland. The results indicate that pathways to adulthood are influenced by social reproduction factors in a country with high levels of welfare benefits as well. In addition, the results suggest that pathways involving living with a partner and either higher education or work are associated with high life satisfaction at age 30.

  2. Learning from Trending, Precursor Analysis, and System Failures

    Energy Technology Data Exchange (ETDEWEB)

    Youngblood, R. W. [Idaho National Laboratory, Idaho Falls, ID (United States); Duffey, R. B. [Idaho National Laboratory, Idaho Falls, ID (United States)

    2015-11-01

    Models of reliability growth relate current system unreliability to currently accumulated experience. But “experience” comes in different forms. Looking back after a major accident, one is sometimes able to identify previous events or measurable performance trends that were, in some sense, signaling the potential for that major accident: potential that could have been recognized and acted upon, but was not recognized until the accident occurred. This could be a previously unrecognized cause of accidents, or underestimation of the likelihood that a recognized potential cause would actually operate. Despite improvements in the state of practice of modeling of risk and reliability, operational experience still has a great deal to teach us, and work has been going on in several industries to try to do a better job of learning from experience before major accidents occur. It is not enough to say that we should review operating experience; there is too much “experience” for such general advice to be considered practical. The paper discusses the following: 1. The challenge of deciding what to focus on in analysis of operating experience. 2. Comparing what different models of learning and reliability growth imply about trending and precursor analysis.

  3. Photovoltaic lithium-ion battery fabricated by molecular precursor method

    Science.gov (United States)

    Nagai, Hiroki; Suzuki, Tatsuya; Takahashi, Yoshihisa; Sato, Mitsunobu

    2016-06-01

    A novel thin-film lithium-ion battery (LIB) which can be charged by the light irradiation was fabricated by molecular precursor method. The unprecedented, translucent thin-film LIB, fabricated on a fluorine-doped tin oxide pre-coated glass substrate, was attained by using the active materials, titania for anode and LiCoO2 for cathode, respectively. The averaged potential at 2.04V was observed by applying a constant current of 0.2mA. Then, that at 1.82V was detected after 60s during the sequential self-discharge process. The charging voltage of the assembled battery was 1.38V with irradiation of 1-sun, the self-discharge voltage was 1.37V. Based on the calibration curve of the charging voltages over constant currents ranging from 0-1.0mA, the detected value can be theoretically reduced to the charging operation by applying a constant current of approximately 60μA. The charge and discharge of this device was stable voltage at least 30 cycles. The two-in-one device can simultaneously generate and store electricity from solar light, the renewable energy source, and may be applied in smart windows for distributed power system according to on-site demand.

  4. Are Nuclear Star Clusters the Precursors of Massive Black Holes?

    Directory of Open Access Journals (Sweden)

    Nadine Neumayer

    2012-01-01

    Full Text Available We present new upper limits for black hole masses in extremely late type spiral galaxies. We confirm that this class of galaxies has black holes with masses less than 106M⊙, if any. We also derive new upper limits for nuclear star cluster masses in massive galaxies with previously determined black hole masses. We use the newly derived upper limits and a literature compilation to study the low mass end of the global-to-nucleus relations. We find the following. (1 The MBH-σ relation cannot flatten at low masses, but may steepen. (2 The MBH-Mbulge relation may well flatten in contrast. (3 The MBH-Sersic n relation is able to account for the large scatter in black hole masses in low-mass disk galaxies. Outliers in the MBH-Sersic n relation seem to be dwarf elliptical galaxies. When plotting MBH versus MNC we find three different regimes: (a nuclear cluster dominated nuclei, (b a transition region, and (c black hole-dominated nuclei. This is consistent with the picture, in which black holes form inside nuclear clusters with a very low-mass fraction. They subsequently grow much faster than the nuclear cluster, destroying it when the ratio MBH/MNC grows above 100. Nuclear star clusters may thus be the precursors of massive black holes in galaxy nuclei.

  5. Diazoxide promotes oligodendrocyte precursor cell proliferation and myelination.

    Directory of Open Access Journals (Sweden)

    Birgit Fogal

    Full Text Available BACKGROUND: Several clinical conditions are associated with white matter injury, including periventricular white matter injury (PWMI, which is a form of brain injury sustained by preterm infants. It has been suggested that white matter injury in this condition is due to altered oligodendrocyte (OL development or death, resulting in OL loss and hypomyelination. At present drugs are not available that stimulate OL proliferation and promote myelination. Evidence suggests that depolarizing stimuli reduces OL proliferation and differentiation, whereas agents that hyperpolarize OLs stimulate OL proliferation and differentiation. Considering that the drug diazoxide activates K(ATP channels to hyperpolarize cells, we tested if this compound could influence OL proliferation and myelination. METHODOLOGY/FINDINGS: Studies were performed using rat oligodendrocyte precursor cell (OPC cultures, cerebellar slice cultures, and an in vivo model of PWMI in which newborn mice were exposed to chronic sublethal hypoxia (10% O(2. We found that K(ATP channel components Kir 6.1 and 6.2 and SUR2 were expressed in oligodendrocytes. Additionally, diazoxide potently stimulated OPC proliferation, as did other K(ATP activators. Diazoxide also stimulated myelination in cerebellar slice cultures. We also found that diazoxide prevented hypomyelination and ventriculomegaly following chronic sublethal hypoxia. CONCLUSIONS: These results identify KATP channel components in OLs and show that diazoxide can stimulate OL proliferation in vitro. Importantly we find that diazoxide can promote myelination in vivo and prevent hypoxia-induced PWMI.

  6. Dry Powder Precursors of Cubic Liquid Crystalline Nanoparticles (cubosomes)

    Science.gov (United States)

    Spicer, Patrick T.; Small, William B.; Small, William B.; Lynch, Matthew L.; Burns, Janet L.

    2002-08-01

    Cubosomes are dispersed nanostructured particles of cubic phase liquid crystal that have stimulated significant research interest because of their potential for application in controlled-release and drug delivery. Despite the interest, cubosomes can be difficult to fabricate and stabilize with current methods. Most of the current work is limited to liquid phase processes involving high shear dispersion of bulk cubic liquid crystalline material into sub-micron particles, limiting application flexibility. In this work, two types of dry powder cubosome precursors are produced by spray-drying: (1) starch-encapsulated monoolein is produced by spray-drying a dispersion of cubic liquid crystalline particles in an aqueous starch solution and (2) dextran-encapsulated monoolein is produced by spray-drying an emulsion formed by the ethanol-dextran-monoolein-water system. The encapsulants are used to decrease powder cohesion during drying and to act as a soluble colloidal stabilizer upon hydration of the powders. Both powders are shown to form (on average) 0.6 μm colloidally-stable cubosomes upon addition to water. However, the starch powders have a broader particle size distribution than the dextran powders because of the relative ease of spraying emulsions versus dispersions. The developed processes enable the production of nanostructured cubosomes by end-users rather than just specialized researchers and allow tailoring of the surface state of the cubosomes for broader application.

  7. Precursors of executive function in infants with sickle cell anemia.

    Science.gov (United States)

    Hogan, Alexandra M; Telfer, Paul T; Kirkham, Fenella J; de Haan, Michelle

    2013-10-01

    Executive dysfunction occurs in sickle cell anemia, but there are few early data. Infants with sickle cell anemia (n = 14) and controls (n = 14) performed the "A-not-B" and Object Retrieval search tasks, measuring precursors of executive function at 9 and 12 months. Significant group differences were not found. However, for the A-not-B task, 7 of 11 sickle cell anemia infants scored in the lower 2 performance categories at 9 months, but only 1 at 12 months (P = .024); controls obtained scores at 12 months that were statistically comparable to the scores they had already obtained at 9 months. On the Object Retrieval task, 9- and 12-month controls showed comparable scores, whereas infants with sickle cell anemia continued to improve (P = .027); at 9 months, those with lower hemoglobin oxygen saturation passed fewer trials (R s = 0.670, P = .024) and took longer to obtain the toy (R s = -0.664, P = .013). Subtle delays in acquiring developmental skills may underlie abnormal executive function in childhood.

  8. Veterinary antibiotics used in animal agriculture as NDMA precursors.

    Science.gov (United States)

    Leavey-Roback, Shannon L; Krasner, Stuart W; Suffet, Irwin Mel H

    2016-12-01

    The formation of carcinogenic N-nitrosodimethylamine (NDMA) during chloramination at drinking water treatment plants has raised concerns as more plants have switched from chlorine to chloramine disinfection. In this study, a source of NDMA precursors that has yet to be investigated was examined. Veterinary antibiotics are used in large quantities at animal agricultural operations. They may contaminate drinking water sources and may not be removed during wastewater and drinking water treatment. Ten antibiotics used in animal agriculture were shown to produce NDMA or N-nitrosodiethylamine (NDEA) during chloramination. Molar conversions ranged from 0.04 to 4.9 percent, with antibiotics containing more than one dimethylamine (DMA) functional group forming significantly more NDMA. The highest formation for most of the compounds was seen near pH 8.4, in a range of pH 6 to 11 that was investigated. The effect of chlorine-to-ammonia ratio (Cl2/NH3), temperature, and hold time varied for each chemical, suggesting that the effects of these parameters were compound-specific.

  9. Altered localization of amyloid precursor protein under endoplasmic reticulum stress.

    Science.gov (United States)

    Kudo, Takashi; Okumura, Masayo; Imaizumi, Kazunori; Araki, Wataru; Morihara, Takashi; Tanimukai, Hitoshi; Kamagata, Eiichiro; Tabuchi, Nobuhiko; Kimura, Ryo; Kanayama, Daisuke; Fukumori, Akio; Tagami, Shinji; Okochi, Masayasu; Kubo, Mikiko; Tanii, Hisashi; Tohyama, Masaya; Tabira, Takeshi; Takeda, Masatoshi

    2006-06-02

    Recent reports have shown that the endoplasmic reticulum (ER) stress is relevant to the pathogenesis of Alzheimer disease. Following the amyloid cascade hypothesis, we therefore attempted to investigate the effects of ER stress on amyloid-beta peptide (Abeta) generation. In this study, we found that ER stress altered the localization of amyloid precursor protein (APP) from late compartments to early compartments of the secretory pathway, and decreased the level of Abeta 40 and Abeta 42 release by beta- and gamma-cutting. Transient transfection with BiP/GRP78 also caused a shift of APP and a reduction in Abeta secretion. It was revealed that the ER stress response facilitated binding of BiP/GRP78 to APP, thereby causing it to be retained in the early compartments apart from a location suitable for the cleavages of Abeta. These findings suggest that induction of BiP/GRP78 during ER stress may be one of the regulatory mechanisms of Abeta generation.

  10. HI-SCALE Nanoparticle Composition and Precursors Field Campaign Report

    Energy Technology Data Exchange (ETDEWEB)

    Smith, James [Univ. of California, Irvine, CA (United States); Stark, Harald [Aerodyne Research, Inc., Billerica, MA (United States); Browne, Eleanor [Univ. of Colorado, Boulder, CO (United States); Hanson, David [Augsburg College, Minneapolis, MN (United States)

    2017-06-15

    From 21 August to 27 September, 2016, during the second Intensive Operational Period (IOP) of the Holistic Interactions of Shallow Clouds, Aerosols, and Land-Ecoystems (HI-SCALE) field campaign, a suite of instruments were placed in the Guest Instrument Facility (GIF) at the Central Facility of the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s Southern Great Plains (SGP) site in Lamont, Oklahoma. The goal of these measurements was to fully characterize the formation and evolution of atmospheric aerosol particles through measurements of gas-phase precursor and ambient nanoparticle composition. Specifically, we sought to: 1. investigate the role of acid-base chemistry in new-particle growth through measurements of ammonia and amines as well as organic and inorganic acids in both atmospheric nanoparticles and the gas phase; 2. investigate the contribution of other surface-area or volume-controlled processes to nanoparticle formation and growth, such as the uptake of extremely low volatility organic compounds (ELVOCs); 3. evaluate the performance of a new instrument being developed with funding from the DOE Small Business Innovation Research (SBIR) program for measuring gas-phase amines and related compounds; and 4. together with colleagues measuring on the ground and onboard the ARM Gulfstream-1 (G-1) aircraft during HI-SCALE, create a comprehensive data set related to new particle formation and growth that can be used in modeling efforts by the research team as well as DOE collaborators.

  11. Accident sequence precursor analysis level 2/3 model development

    Energy Technology Data Exchange (ETDEWEB)

    Lui, C.H. [Nuclear Regulatory Commission, Washington, DC (United States); Galyean, W.J.; Brownson, D.A. [Idaho National Engineering Lab., Idaho Falls, ID (United States)] [and others

    1997-02-01

    The US Nuclear Regulatory Commission`s Accident Sequence Precursor (ASP) program currently uses simple Level 1 models to assess the conditional core damage probability for operational events occurring in commercial nuclear power plants (NPP). Since not all accident sequences leading to core damage will result in the same radiological consequences, it is necessary to develop simple Level 2/3 models that can be used to analyze the response of the NPP containment structure in the context of a core damage accident, estimate the magnitude of the resulting radioactive releases to the environment, and calculate the consequences associated with these releases. The simple Level 2/3 model development work was initiated in 1995, and several prototype models have been completed. Once developed, these simple Level 2/3 models are linked to the simple Level 1 models to provide risk perspectives for operational events. This paper describes the methods implemented for the development of these simple Level 2/3 ASP models, and the linkage process to the existing Level 1 models.

  12. Control of Bromate and THM Precursors Using Ozonation Combined System

    Institute of Scientific and Technical Information of China (English)

    SHU-GUANG XIE; DONG-WEN SHI; DONG-HUI WEN; RUI WANG; DAN-LI XI

    2007-01-01

    Objective To investigate the feasibility of reducing THM precursors and controlling bromate taste and odor in drinking water taken from the Yellow River by an ozonation combined system. Methods The appropriate ozone dosage was determined,and then the changes of TOC,UV254 and THM formation potential(THMFP)in the combined system were evaluated. Results One mg/L ozone could effectively remove taste and odor and meet the maximum allowable bromate level in drinking water.The pre-ozonation increased THMFP,but the conventional treatment system could effectively reduce the odor.The bio-ceramic filter could partly reduce CHCI3FP,but sometimes might increase CHCI2BrFP and CHCIBr2FP.The biological activated carbon(BAC)filter could effectively reduce CHCI3FP and CHCI2BrFP,but increase CHCIBr2FP.Compared with other filters.the fresh activated carbon(FAC)filter performed better in reducing THMFP and even reduced CHCIBrzFP.Conclusion The combined system can effectively reduce taste,odor,CHCI3FP,and CHCI2BrFP and also bring bromate under control.

  13. Preparation of zinc sulfide nanocrystallites from single-molecule precursors

    Science.gov (United States)

    Palve, Anil M.; Garje, Shivram S.

    2011-07-01

    Zinc sulfide nanocrystallites were prepared using Zinc(II) thiosemicarbazone complexes of the types Zn(L) 2 and ZnCl 2(LH) 2 (where, LH=thiosemicarbazones of cinnamaldehyde, 4-chlorobenzaldehyde, indol-3-carboxaldehyde and thiophene-2-carboxaldehyde) as single source precursors by solvothermal decomposition in ethylene glycol and ethylene diamine in few cases. The materials were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction, energy dispersive X-ray analysis and UV-vis and IR spectroscopy. Solvothermal decomposition in ethylene glycol resulted in the formation of hexagonal ZnS (JCPDS: 36-1450) as evident from the XRD patterns. However, XRD shows formation of hybrid material, ZnS 0.5EN in case of solvothermal decomposition in ethylenediamine. Infrared spectra authenticate the capping of ethylene glycol and ethylenediamine on ZnS and ZnS 0.5EN, respectively. TEM images showed formation of spherical nanoparticles for the materials obtained from ethylene glycol, whereas plate-like morphology is observed in case of materials obtained from ethylene diamine. The blue shift of absorption bands compared to bands of bulk materials in the UV-vis spectra supports the formation of smaller particles.

  14. Vaginal epithelial dendritic cells renew from bone marrow precursors.

    Science.gov (United States)

    Iijima, Norifumi; Linehan, Melissa M; Saeland, Sem; Iwasaki, Akiko

    2007-11-27

    Dendritic cells (DCs) represent key professional antigen-presenting cells capable of initiating primary immune responses. A specialized subset of DCs, the Langerhans cells (LCs), are located in the stratified squamous epithelial layer of the skin and within the mucosal epithelial lining of the vaginal and oral cavities. The vaginal mucosa undergoes cyclic changes under the control of sex hormones, and the renewal characteristics of the vaginal epithelial DCs (VEDCs) remain unknown. Here, we examined the origin of VEDCs. In contrast to the skin epidermal LCs, the DCs in the epithelium of the vagina were found to be repopulated mainly by nonmonocyte bone-marrow-derived precursors, with a half-life of 13 days under steady-state conditions. Upon infection with HSV-2, the Gr-1(hi) monocytes were found to give rise to VEDCs. Furthermore, flow cytometric analysis of the VEDCs revealed the presence of at least three distinct populations, namely, CD11b(+)F4/80(hi), CD11b(+)F4/80(int), and CD11b(-)F4/80(-). Importantly, these VEDC populations expressed CD207 at low levels and had a constitutively more activated phenotype compared with the skin LCs. Collectively, our results revealed mucosa-specific features of the VEDCs with respect to their phenotype, activation status, and homeostatic renewal potential.

  15. Toroidally asymmetric ELM precursor oscillations in the TCV tokamak

    Energy Technology Data Exchange (ETDEWEB)

    Reimerdes, H.; Pochelon, A.; Guittienne, P.; Weisen, H. [Ecole Polytechnique Federale, Lausanne (Switzerland). Centre de Recherche en Physique des Plasma (CRPP); Suttrop, W. [Max-Planck Inst. fuer Plasmaphysik, Garching (Germany)

    1997-06-01

    In TCV ohmic H-modes have been obtained in diverted single-null (SND), double-null (DND), and elongated limited plasma configurations. In ELM-free H-modes the particle density rises continuously until the discharge usually terminates with a high density disruption. Quasi-stationary H-modes have been obtained in the presence of ELMs. The observed ELM spectrum is continuous and ranges from clearly identifiable type III ELMs to low frequency, large ELMs. The necessity of ELMs for particle control of H-mode plasmas while causing high peak-power loads on strike points makes the control of their level and nature desirable and motivates the study of the underlying MHD-instability. Prior to ELMs in TCV coherent magnetic oscillations, that indicate a rapidly growing MHD instability, have been observed. The structure of these precursor oscillation is investigated with TCV`s Mirnov probe arrays. In particular an observed toroidal asymmetry in the growth of the instability has to be explained. (author) 2 figs., 6 refs.

  16. High frequency microseismic noise as possible earthquake precursor

    Directory of Open Access Journals (Sweden)

    Ivica Sović

    2013-08-01

    Full Text Available Before an earthquake occurs, microseismic noise in high frequency (HF range, i.e. 2-25 Hz, is being generated during preparation process. These signals change the microseismic noise and, consequently, the spectrum of microseismic noise. Time variation of spectra recorded at the same seismological station could imply the change of the state of noise source. We propose the image moment analysis approach to objectively compare microseismic noise spectra. The result could be used for earthquake precursor identification. Expected spectra change is in HF range, so the analysis has been limited to the shallow tectonic earthquakes with epicenters close, up to 15 km, the seismological stations. The method has been tested post festum using four earthquakes in Dinarides which satisfied condition for epicentral distance. The spectra were calculated for noise recorded in time intervals of 10 days before and 6 to 10 days after the earthquakes. Affine moment invariants were calculated for noise spectra which were treated as the input objects. Spectra of the first five days in the series were referent spectra. The classification parameters were Euclidean distances between referent spectra and the spectra for all days in the series, including referent ones. The results have shown that the spectra of the microseismic noise become noticeably different than the other spectra in time intervals one or two days before an earthquake.

  17. Ceramic Films via Organometallic Complex as Single Source Precursor

    Institute of Scientific and Technical Information of China (English)

    Shyu Shin-Guang; Wu Juan-Seng; Wu Chi-Chin; Chi Kal-Ming

    2004-01-01

    Fe2(CO)6(μ-S2) was used as a single source precursor in attempt to produce FeS film via MOCVD. Pyrolysis of Fe2(CO)6(μ-S2) at temperature below 500℃ produced Fe1-xS or Fe7S8 powder as indicated by its powder X-ray spectra. At 750 ℃, polycrystalline FeS powder was obtained. In film deposition, polycrystalline Fe1-xS or Fe7Ss films were obtained on Si(100) and Ag/Si(100) substrates below 500 ℃. SEM micrographs showed the film on Si(100) substrate containing whisker like grains. However, pillar like grains were obtained on Ag/Si(100) substrate.Deposition rates are also different for different substrates as evaluated by the thickness of the films, which were obtained by SEM micrographs of the cross section of the films. At 750℃, similar polycrystalline Fe1-xS or Fe7S8 film was obtained.

  18. Analytical characterization of wine and its precursors by capillary electrophoresis.

    Science.gov (United States)

    Gomez, Federico J V; Monasterio, Romina P; Vargas, Verónica Carolina Soto; Silva, María F

    2012-08-01

    The accurate determination of marker chemical species in grape, musts, and wines presents a unique analytical challenge with high impact on diverse areas of knowledge such as health, plant physiology, and economy. Capillary electromigration techniques have emerged as a powerful tool, allowing the separation and identification of highly polar compounds that cannot be easily separated by traditional HPLC methods, providing complementary information and permitting the simultaneous analysis of analytes with different nature in a single run. The main advantage of CE over traditional methods for wine analysis is that in most cases samples require no treatment other than filtration. The purpose of this article is to present a revision on capillary electromigration methods applied to the analysis of wine and its precursors over the last decade. The current state of the art of the topic is evaluated, with special emphasis on the natural compounds that have allowed wine to be considered as a functional food. The most representative revised compounds are phenolic compounds, amino acids, proteins, elemental species, mycotoxins, and organic acids. Finally, a discussion on future trends of the role of capillary electrophoresis in the field of analytical characterization of wines for routine analysis, wine classification, as well as multidisciplinary aspects of the so-called "from soil to glass" chain is presented.

  19. Sustainable Life Cycles of Natural-Precursor-Derived Nanocarbons.

    Science.gov (United States)

    Bazaka, Kateryna; Jacob, Mohan V; Ostrikov, Kostya Ken

    2016-01-13

    Sustainable societal and economic development relies on novel nanotechnologies that offer maximum efficiency at minimal environmental cost. Yet, it is very challenging to apply green chemistry approaches across the entire life cycle of nanotech products, from design and nanomaterial synthesis to utilization and disposal. Recently, novel, efficient methods based on nonequilibrium reactive plasma chemistries that minimize the process steps and dramatically reduce the use of expensive and hazardous reagents have been applied to low-cost natural and waste sources to produce value-added nanomaterials with a wide range of applications. This review discusses the distinctive effects of nonequilibrium reactive chemistries and how these effects can aid and advance the integration of sustainable chemistry into each stage of nanotech product life. Examples of the use of enabling plasma-based technologies in sustainable production and degradation of nanotech products are discussed-from selection of precursors derived from natural resources and their conversion into functional building units, to methods for green synthesis of useful naturally degradable carbon-based nanomaterials, to device operation and eventual disintegration into naturally degradable yet potentially reusable byproducts.

  20. Seismic event classification and precursor identification at Fuego Volcano, Guatemala

    Science.gov (United States)

    Brill, K. A.; Waite, G. P.; Rodriguez, K.

    2013-12-01

    Understanding the nature and origins of seismic signals generated by volcanic activity can greatly aid in hazard mitigation efforts. Systematic identification and detailed cataloging of explosive events provide a first step for this understanding, and can be even more valuable when the events span longer time periods. Beyond simply being a more useful monitoring tool, the detailed classification of events can illuminate the processes behind different conduit flow phenomena such as rheological sealing or piston-style chugging. Fuego volcano, Guatemala, is a basaltic-andesite stratovolcano that has been continually active since 1999. Activity is characterized by small-scale explosive eruptions and intermittent lava flows. In this study, we categorize different events recorded with a 10 station temporary seismic array at Fuego volcano in Guatemala in January 2012 that included infrasound and tilt sensors. Waveform analysis, along with visual and thermal characteristics captured by cameras allow us to identify precursory activity in different bandwidths that precedes some of the event types. We investigate the physical mechanisms behind these precursors to explain why some event types exhibit them while others may not, and how these mechanisms influence our conceptual models of explosion dynamics at Fuego. Finally, we compare events recorded in 2012 with other studies conducted at Fuego volcano in previous years to identify changes in the signal characteristics and their potential influences on activity styles observed during different field campaigns to highlight the importance of longitudinal studies at persistently active volcanic systems.

  1. Selective Behaviour of Honeybees in Acquiring European Propolis Plant Precursors.

    Science.gov (United States)

    Isidorov, Valery A; Bakier, Sławomir; Pirożnikow, Ewa; Zambrzycka, Monika; Swiecicka, Izabela

    2016-06-01

    Honey bees harvest resins from various plant species and use them in the hive as propolis. While there have been a number of studies concerning the chemical composition of this antimicrobial product, little is known about selective behavior and bee preference when different potential plant sources of resin are available. The main objective of this paper was to investigate some aspects of behavioral patterns of honeybees in the context of resin acquisition. Samples of propolis originating from temperate zones of Europe and the supposed botanical precursors of the product were analyzed. Taxonomical markers of bud resins of two white birch species, aspen, black poplar, horse-chestnut, black alder, and Scots pine were determined through GC-MS analysis. All these trees have been reported as sources of propolis, but comparisons of the chemical composition of their bud resins with the compositions of propolis samples from seven European countries have demonstrated the presence of taxonomical markers only from black poplar, aspen, and one species of birch. This suggests selective behavior during the collection of bud resins by honeybees. To examine the causes of such selectivity, the antimicrobial properties of bud resins were determined. Horse-chestnut resins had lower antimicrobial activity than the other resins which did not differ significantly.

  2. Searching for Dynamical Earthquake Precursors with Surrogate Data

    Science.gov (United States)

    Lynch, J.; Revenaugh, J.; Georgopoulos, A.

    2007-12-01

    Surrogate data methods are resampling techniques related to the modern statistical bootstrap. The nonlinear dynamics community has promoted surrogate data as a useful tool for establishing the presence of nonlinear dynamics in experimental observations before applying more specific techniques such as nonlinear prediction. We propose to use surrogate data tests to search for evidence of transient nonlinear dynamics in seismographic data that act as a proxy for earthquake triggering mechanisms, such as fluid flow in the fault zone, failure cascades and slow prefatory slip, that signal changes in the coupling between geological boundaries. We will analyze the vertical component of broadband seismographic data recorded at 20Hz by the CI network of approximately 100 stations located throughout Southern California. We will focus on a period of six hours prior to seismic events of magnitude 4-5 located inside the CI network. Each seismographic record will be scanned for short, non-overlapping segments that pass a moderate stationarity criterion. We will then apply surrogate tests to each qualifying segment using three discriminating statistics: time reversal asymmetry, delay vector variance and zeroth-order nonlinear prediction error. We will correlate the results with known seismic activity and examine the spatial and temporal distribution of the surrogate test results for potential dynamical earthquake precursors.

  3. Sulfate radicals enable a non-enzymatic Krebs cycle precursor.

    Science.gov (United States)

    Keller, Markus A; Kampjut, Domen; Harrison, Stuart A; Ralser, Markus

    2017-03-13

    The evolutionary origins of the Krebs cycle (tricarboxylic acid cycle) are not currently clear. Despite the existence of a simple non-enzymatic Krebs cycle catalyst being dismissed only a few years ago as 'an appeal to magic', citrate and other intermediates have since been discovered on a carbonaceous meteorite and do interconvert non-enzymatically. To identify a metabolism-like non-enzymatic Krebs cycle catalyst, we used combinatorial, quantitative high-throughput metabolomics to systematically screen iron and sulfate compounds in a reaction mixture that orients on the typical components of Archaean sediment. Krebs cycle intermediates were found to be stable in water and in the presence of most molecule species, including simple iron sulfate minerals. However, in the presence of sulfate radicals generated from peroxydisulfate, the intermediates underwent 24 interconversion reactions. These non-enzymatic reactions covered the critical topology of the oxidative Krebs cycle, the glyoxylate shunt and the succinic-semialdehyde pathway. Assembled in a chemical network, the reactions achieved over 90% carbon recovery. Our results show that a non-enzymatic precursor of the Krebs cycle is biologically sensible, efficient, and forms spontaneously in the presence of sulfate radicals.

  4. Utilization of Mineral Wools as Alkali-Activated Material Precursor

    Directory of Open Access Journals (Sweden)

    Juho Yliniemi

    2016-04-01

    Full Text Available Mineral wools are the most common insulation materials in buildings worldwide. However, mineral wool waste is often considered unrecyclable because of its fibrous nature and low density. In this paper, rock wool (RW and glass wool (GW were studied as alkali-activated material precursors without any additional co-binders. Both mineral wools were pulverized by a vibratory disc mill in order to remove the fibrous nature of the material. The pulverized mineral wools were then alkali-activated with a sodium aluminate solution. Compressive strengths of up to 30.0 MPa and 48.7 MPa were measured for RW and GW, respectively, with high flexural strengths measured for both (20.1 MPa for RW and 13.2 MPa for GW. The resulting alkali-activated matrix was a composite-type in which partly-dissolved fibers were dispersed. In addition to the amorphous material, sodium aluminate silicate hydroxide hydrate and magnesium aluminum hydroxide carbonate phases were identified in the alkali-activated RW samples. The only crystalline phase in the GW samples was sodium aluminum silicate. The results of this study show that mineral wool is a very promising raw material for alkali activation.

  5. Therapeutic Potential of Secreted Amyloid Precursor Protein APPsα

    Science.gov (United States)

    Mockett, Bruce G.; Richter, Max; Abraham, Wickliffe C.; Müller, Ulrike C.

    2017-01-01

    Cleavage of the amyloid precursor protein (APP) by α-secretase generates an extracellularly released fragment termed secreted APP-alpha (APPsα). Not only is this process of interest due to the cleavage of APP within the amyloid-beta sequence, but APPsα itself has many physiological properties that suggest its great potential as a therapeutic target. For example, APPsα is neurotrophic, neuroprotective, neurogenic, a stimulator of protein synthesis and gene expression, and enhances long-term potentiation (LTP) and memory. While most early studies have been conducted in vitro, effectiveness in animal models is now being confirmed. These studies have revealed that either upregulating α-secretase activity, acutely administering APPsα or chronic delivery of APPsα via a gene therapy approach can effectively treat mouse models of Alzheimer’s disease (AD) and other disorders such as traumatic head injury. Together these findings suggest the need for intensifying research efforts to harness the therapeutic potential of this multifunctional protein.

  6. Titanite mineralization of bioalteration textures - the possible Ti precursor

    Science.gov (United States)

    Fliegel, D.; Wirth, R.; Simonetti, A.; McLoughlin, N.; Furnes, H.

    2009-12-01

    Bioalteration textures in the glassy rims of pillow basalts are found in in-situ oceanic crust of any age, in Phanerozoic ophiolites and from Precambrian greenstone belts. In ancient and metamorphosed rocks, these bioalteration textures are often mineralized by titanite (CaSiTiO5). The presence of titanite provides a way to constrain the age of these tracefossils using in-situ U-Pb dating with LA-MC-ICPMS. Until now the pathway for mineralization by titanite was unclear. We investigate here bioalteration textures from in-situ oceanic crust (DSDP 418A) using transmission electron microscopy (TEM), electron energy loss spectrometry (EELS) and scanning transmission X-ray microscopy (STXM). Using high spatial resolved spectroscopy, Ti enrichments and the Ti speciation was determined in the bioalteration textures. In addition TEM and EELS revealed the microstructure of the bioalteration textures and with STXM the redox chemistry at the interface between texture and host glass was examined. The observed Ti can serve as precursor for subsequent titanite mineralization during sub-seafloor and/or later regional metamorphism. We present here therefore a model for the mineralization and thus preservation of bioalteration textures in the oceanic crust.

  7. Photodissociation dynamics of ethyl ethynyl ether: A ketenyl radical precursor

    Science.gov (United States)

    Krisch, Maria; Miller, Johanna; Butler, Laurie; Su, Hongmei; Bersohn, Richard; Shu, Jinian

    2006-03-01

    We investigate the photodissociation dynamics of ethyl ethynyl ether at 193.3 nm with crossed laser-molecular beam photofragment translational spectroscopy and laser-induced fluorescence. We establish ethyl ethynyl ether as the first clean precursor to the ketenyl radical, a key species in combustion reactions. One major bond fission channel was observed for the system, cleavage along the HCCO-C2H5 bond, leading to ground state C2H5 (ethyl) radicals and HCCO (ketenyl) radical products in two distinct electronic states. We observed neither cleavage of the other C-O bond nor molecular elimination to form C2H4 + CH2CO (ketene). Ketenyl radicals formed in the higher recoil kinetic energy channel could be either X(^2A") or Ã(^2A') state ketenyl radical. We assign the lower recoil kinetic energy channel to the spin forbidden ã(^4A") state of the ketenyl radical, reached through intersystem crossing. Laser-induced fluorescence from the ketenyl radical peaks after a 20 μs delay, indicating that it is formed with a significant amount of internal energy and subsequently relaxes to the lowest vibrational level of the ground electronic state, a result consistent with the product assignment.

  8. Effects of Peer Mediation on Preschoolers' Compliance and Compliance Precursors

    Science.gov (United States)

    Beaulieu, Lauren; Hanley, Gregory P.; Roberson, Aleasha A.

    2013-01-01

    We used a multiple baseline design across participants to evaluate the effects of teaching 4 typically developing preschoolers to attend to their names and to a group call (referred to as "precursors") on their compliance with typical classroom instructions. We then measured the extent to which the effects on both precursors and…

  9. Detecting the onset of bifurcations and their precursors from noisy data

    Energy Technology Data Exchange (ETDEWEB)

    Omberg, Larsson [Center for Neurodynamics, University of Missouri at St. Louis, St. Louis, Missouri 63121 (United States); Royal Institute of Technology (KTH), Stockholm, (Sweden); Dolan, Kevin [Center for Neurodynamics, University of Missouri at St. Louis, St. Louis, Missouri 63121 (United States); Neiman, Alexander [Center for Neurodynamics, University of Missouri at St. Louis, St. Louis, Missouri 63121 (United States); Moss, Frank [Center for Neurodynamics, University of Missouri at St. Louis, St. Louis, Missouri 63121 (United States)

    2000-05-01

    We study the problem of the detection of noise-induced precursors of periodic motion instabilities in stochastic dynamical systems. In particular, we concentrate on the period-doubling bifurcation. We have developed a statistical method to detect the onset of bifurcations and their precursors based on the previously established topological recurrence technique. (c) 2000 The American Physical Society.

  10. Opioid precursor protein isoform is targeted to the cell nuclei in the human brain

    NARCIS (Netherlands)

    Kononenko, Olga; Bazov, Igor; Watanabe, Hiroyuki; Gerashchenko, Ganna; Dyachok, Oleg; Verbeek, Dineke S; Alkass, Kanar; Druid, Henrik; Andersson, Malin; Mulder, Jan; Svenningsen, Åsa Fex; Rajkowska, Grazyna; Stockmeier, Craig A; Krishtal, Oleg; Yakovleva, Tatiana; Bakalkin, Georgy

    2017-01-01

    BACKGROUND: Neuropeptide precursors are traditionally viewed as proteins giving rise to small neuropeptide molecules. Prodynorphin (PDYN) is the precursor protein to dynorphins, endogenous ligands for the κ-opioid receptor. Alternative mRNA splicing of neuropeptide genes may regulate cell- and tissu

  11. OPIOID PRECURSOR PROTEIN ISOFORM IS TARGETED TO THE CELL NUCLEI IN THE HUMAN BRAIN

    DEFF Research Database (Denmark)

    Kononenko, Olga; Bazov, Igor; Watanabe, Hiroyuki;

    2016-01-01

    Neuropeptide precursors are traditionally viewed as proteins giving rise to small neuropeptide molecules. Prodynorphin (PDYN) is the precursor protein to dynorphins, endogenous ligands for the κ-opioid receptor. We here describe two novel splicing variants of human PDYN mRNA. Expression of one...

  12. Stable amorphous georgeite as a precursor to a high-activity catalyst

    DEFF Research Database (Denmark)

    Kondrat, Simon A.; Smith, Paul J.; Wells, Peter P.

    2016-01-01

    and solvation power of supercritical carbon dioxide to rapidly expand and supersaturate solutions, can be used to prepare copper/zinc hydroxycarbonate precursors with low sodium content. These include stable georgeite, which we find to be a precursor to highly active methanol-synthesis and superior LTS...

  13. One-pot native chemical ligation by combination of two orthogonal thioester precursors.

    Science.gov (United States)

    Asahina, Yuya; Kawakami, Toru; Hojo, Hironobu

    2017-02-09

    We developed a one-pot peptide ligation method using two orthogonal thioester precursors and a protecting group for the ligation reaction between Asp and Cys. Combination of the two precursors facilitated the one-pot operation and yielded the entire polypeptide. The usefulness of this method was successfully demonstrated by the total synthesis of histone H4.

  14. Spray Deposited Nanocrystalline ZnO Transparent Electrodes: Role of Precursor Solvent

    Directory of Open Access Journals (Sweden)

    C.M. Mahajan

    2016-06-01

    Full Text Available Nanocrystalline ZnO thin films were deposited by intermittent spray pyrolysis using different alcoholic and aqua-alcoholic precursor solvents. The XRD analysis reveals the polycrystallinity of hexagonal wurtzite type ZnO films with preferred c-axis orientation along [002] direction. The polycrystallinity increased due to use of aqua-alcoholic precursor solvent. The crystallite size was found to vary from 41.7 nm to 59.4 nm and blue shift in band-gap energy (3.225 eV to 3.255 eV was observed due to aqua-alcoholic to alcoholic precursor solvent transition. The films deposited using alcoholic precursor solvent exhibited high transmittance (> 92 % with low dark resistivity (10 – 3 Ω·cm as compared to aqua-alcoholic precursor solvent. The effect of precursor solvent on resistivity, carrier concentration (η – /cm3, carrier mobility (μ – cm2V – 1s – 1, sheet resistance (Ω/ and figure of merit (ΦTC is also reported. We recommend ethanol or methanol as a superior precursor solvent over aqua-alcoholic precursor solvent for deposition of device quality ZnO thin films.

  15. FT-IR and 29 Si-NMR for evaluating aluminium silicate precursors for geopolymers

    NARCIS (Netherlands)

    Valcke, S.L.A.; Pipilikaki, P.; Fischer, H.R.; Verkuijlen, M.H.W.; Eck, E.R.H.

    2014-01-01

    Geopolymers are systems of inorganic binders that can be used for sustainable, cementless concrete and are formed by alkali activation of an aluminium–silicate precursor (often secondary resources like fly ash or slag). The type of aluminium– silicate precursor and its potential variations within on

  16. The theory of planned behavior: Precursors of marijuana use in early adolescence?

    NARCIS (Netherlands)

    Malmberg, M.; Overbeek, G.J.; Vermulst, A.A.; Monshouwer, K.; Vollebergh, W.A.M.; Engels, R.C.M.E.

    2012-01-01

    Background: Precursors of marijuana use in early adolescence are largely unknown because studies generally focus on marijuana use among older adolescents or adults. Methods: In this study, we examined precursors of marijuana use in a sample of 1023 Dutch early adolescents (aged 11-14 at Time 1) who

  17. The theory of planned behavior: Precursors of marijuana use in early adolescence?

    NARCIS (Netherlands)

    Malmberg, M.; Overbeek, G.J.; Vermulst, A.A.; Monshouwer, K.; Vollebergh, W.A.M.; Engels, R.C.M.E.

    2012-01-01

    Background: Precursors of marijuana use in early adolescence are largely unknown because studies generally focus on marijuana use among older adolescents or adults. Methods: In this study, we examined precursors of marijuana use in a sample of 1023 Dutch early adolescents (aged 11-14 at Time 1) who

  18. Plasma glutamine is a minor precursor for the synthesis of citrulline: A multispecies study

    Science.gov (United States)

    Glutamine is considered the main precursor for citrulline synthesis in many species, including humans. The transfer of 15N from 2[15N]-glutamine to citrulline has been used as evidence for this precursor-product relationship. However, work in mice has shown that nitrogen and carbon tracers follow di...

  19. Mechanistic modeling study on process optimization and precursor utilization with atmospheric spatial atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Zhang; He, Wenjie; Duan, Chenlong [State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Chen, Rong, E-mail: rongchen@mail.hust.edu.cn [State Key Laboratory of Digital Manufacturing Equipment and Technology, School of Mechanical Science and Engineering, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Shan, Bin [State Key Laboratory of Material Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China)

    2016-01-15

    Spatial atomic layer deposition (SALD) is a promising technology with the aim of combining the advantages of excellent uniformity and conformity of temporal atomic layer deposition (ALD), and an industrial scalable and continuous process. In this manuscript, an experimental and numerical combined model of atmospheric SALD system is presented. To establish the connection between the process parameters and the growth efficiency, a quantitative model on reactant isolation, throughput, and precursor utilization is performed based on the separation gas flow rate, carrier gas flow rate, and precursor mass fraction. The simulation results based on this model show an inverse relation between the precursor usage and the carrier gas flow rate. With the constant carrier gas flow, the relationship of precursor usage and precursor mass fraction follows monotonic function. The precursor concentration, regardless of gas velocity, is the determinant factor of the minimal residual time. The narrow gap between precursor injecting heads and the substrate surface in general SALD system leads to a low Péclet number. In this situation, the gas diffusion act as a leading role in the precursor transport in the small gap rather than the convection. Fluid kinetics from the numerical model is independent of the specific structure, which is instructive for the SALD geometry design as well as its process optimization.

  20. Vaporization of a mixed precursors in chemical vapor deposition for YBCO films

    Science.gov (United States)

    Zhou, Gang; Meng, Guangyao; Schneider, Roger L.; Sarma, Bimal K.; Levy, Moises

    1995-01-01

    Single phase YBa2Cu3O7-delta thin films with T(c) values around 90 K are readily obtained by using a single source chemical vapor deposition technique with a normal precursor mass transport. The quality of the films is controlled by adjusting the carrier gas flow rate and the precursor feed rate.