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Sample records for experimentales sobre shock

  1. Modelos experimentales de anafilaxia

    OpenAIRE

    Yazmín Ravelo Calzado; Vivian Molina Cuevas; María de Lourdes Arruzazabala Valmaña; Daisy Carbajal Quintana

    2009-01-01

    Los modelos experimentales constituyen una herramienta clave en la búsqueda de nuevas opciones para el tratamiento y profilaxis de diversas condiciones patológicas. La anafilaxia, síndrome clínico con manifestaciones multisistémicas como urticaria, asma, vasodilatación sistémica, hipotensión y shock, entre otras, no resulta una excepción. El objetivo del presente trabajo consistió en presentar algunos de los modelos experimentales utilizados en la evaluación de sustancias con potenciales efec...

  2. Nuevos datos experimentales sobre parámetros hidrogeológicos de la Cuenca de Madrid obtenidos a partir de muestras de sondeos

    Directory of Open Access Journals (Sweden)

    Villarroya Gil, F. I.

    1990-12-01

    Full Text Available A critical review of main hydrogeological parameters (porosity, permeability and specific storage coefficient of Madrid Basin Detrital Aquifer is done. For this study, data from the bibliography and new laboratory analysis of grain size distribution (26, dry density (26, specific weight (26, permeability (20 and consolidation test (6 samples from three boreholes are used. The results are quite similar to those than already exist in the literature, although the porosity obtained is higher.Se hace una revisión crítica de los principales parámetros hidrogeológicos (porosidad, permeabilidad y coeficiente de almacenamiento específico, del Terciario detrítico de la cuenca de Madrid. Para este estudio además de los datos existentes en la bibliografía, se han realizado una serie de análisis de laboratorio desarrollados en las instalaciones del SGOP obteniendo, de esta manera, nuevos valores experimentales de los citados parámetros, mediante ensayos granulométricos (26, de densidad seca (26, de peso específico (26, de permeabilidad (20 y ensayos edométricos (6. Las muestras proceden de tres sondeos realizados en el casco urbano de Madrid por el SGOP (MOPU. Los resultados obtenidos coinciden, en gran medida, con los existentes en la bibliografía, si bien, los valores de porosidad total son marcadamente más altos.

  3. Evaluación de la actividad insecticida de un producto granulado a base de Bacillus sphaericus sobre larvas de Anopheles albimanus y Culex quinquefasciatus en condiciones experimentales

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    Estrella Cárdenas

    2009-01-01

    Full Text Available Culex quinquefasciatus causa alergias por las picaduras y ha sido asociado con la encefalitis equina, mientras que Anopheles albimanus es vector de malaria. El objetivo fue evaluar la toxicidad de un producto granulado a base de Bacillus sphaericus sobre larvas de Culex quinquefasciatus y Anopheles albimanus. El estudio fue realizado sobre larvas de C. quinquefasciatus (Sibaté y Villavicencio y An albimanus (Cartagena y Barranquilla. Las concentraciones ensayadas de B. sphaericus fueron: 20, 40, 60, 80, 100, 120, 140, 160, 180, 200 y 500 ppm para larvas de An. albimanus y para larvas de C. quinquefasciatus fueron: 2, 4, 6, 8, 10, 12, 14 y 16 ppm. Se utilizaron 20 larvas en tres repeticiones por cada concentración del producto y el tiempo de exposición fue de 48 horas. El producto de B. sphaericus mostró alta mortalidad (entre 80 y 100% a bajas concentraciones (8 y 12 ppm para larvas de C. quinquefasciatus; mientras que para larvas de An. albimanus a concentraciones más altas (entre 40 y 200 ppm la mortalidad no superó el 50%. La CL50 Logit fue 176 ppm y la Probit fue 192 ppm de B. sphaericus para larvas de An. albimanus; mientras que para larvas de C. quinquefasciatus la CL50 Logit fue 1, 9 ppm y la Probit fue 2, 2 ppm. Se concluye que las larvas de C. quinquefasciatus fueron más susceptibles a bajas concentraciones (2 a 12 ppm de B. sphaericus, mientras que las larvas de An. albimanus mostraron alta toxicidad a concentraciones de 500 ppm.

  4. La restauración alfarera en la funebria arqueológica. Observaciones y estudios experimentales sobre la colección Muñiz Barreto

    Directory of Open Access Journals (Sweden)

    2002-01-01

    Full Text Available LA RESTAURATION CÉRAMIQUE DES PIÈCES ARQUÉOLOGIQUES FUNÉRAIRES. OBSERVATIONS ET ÉTUDES EXPÉRIMENTALES SUR LA COLLECTION MUÑIZ BARRETO. Le but de ce travail est de décrire le mode particulier de restauration des pièces arquéologiques de céramique funéraire de la collection Muñiz Barreto du Musée de La Plata, et la récuperation des techniques utilisées pour la confection de ces objets. On cherche ensuite à mettre à jour les procédés éventuels et leurs significations possibles. Los objetivos del presente trabajo consisten en la descripción de una forma particular de restauración en objetos cerámicos funerarios pertenecientes a la Colección Muñiz Barreto del Museo de La Plata y la recuperación de las operaciones técnicas realizadas para reparar dichos objetos. A partir de la consecución de los mismos, se plantea realizar inferencias sobre las conductas puestas en marcha y sus posibles significados subyacentes. POTTERY RESTORATION IN FUNERARY ARCHAEOLOGICAL VESSELS. OBSERVATION AND STUDIES ABOUT THE MUÑIZ BARRETO COLLECTION. The present paper consists in the description of a particular kind of restoration applied to funerary pottery vessels belonging to Colección Muñiz Barreto of La Plata Museum and the recovery of the techniques used in the restoration. This knowledge will allow us making inferences about the conduct of potters and its underlying significances.

  5. Primer estudio de artropodofauna cadavérica sobre modelos experimentales porcinos en el noreste de la provincia del Chubut, Argentina

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    Ana P. ARMANI

    2015-01-01

    Full Text Available En este trabajo se estudió el proceso de descomposición y la composición de insectos presentes en biomodelos porcinos, en el NE de la provincia del Chubut. El objetivo fue determinar la composición específica, abundancia y riqueza de la artropodofauna carroñera en el ambiente de estepa. Se realizaron muestreos estacionales durante tres años consecutivos utilizándose tres cerdos domésticos para cada muestreo, colocados dentro de jaulas de madera cubiertas de alambre tejido. Diariamente se colectaron los artrópodos en el cuerpo, debajo y alrededor de este. Se registraron 36.157 individuos pertenecientes a 78 especies de 18 familias distribuidas entre los órdenes Diptera, Coleoptera e Hymenoptera. Se citan por primera vez de la provincia de Chubut tres especies de Calliphoridae: Paralucilia pseudolyrcea Mello, Paralucilia fulvinota Bigot y Chrysomya albiceps Wiedemann; y una especie de Muscidae: Arthurella choelensis Patitucci & Mariluis. Se incorpora como primera cita para la fauna cadavérica argentina a Sarcophaga (Lipoptilocnema margaretae Lahille (Sarcophagidae. Se trata del primer estudio sobre entomología forense realizado en Patagonia que permite conocer los procesos de descomposición cadavérica y la fauna de insectos carroñeros presentes en esta zona. Por lo tanto, aporta información relevante que puede utilizarse en la resolución de casos forenses humanos en la región.

  6. Caracterización del borde de un relicto de bosque altoandino dominado por Chusquea scandens (Kunth y evaluación del efecto de disturbios experimentales sobre la regeneración natural en la Reserva forestal municipal de Cogua (Cundinamarca, Colombia

    Directory of Open Access Journals (Sweden)

    Vargas Ríos Orlando

    2004-12-01

    Full Text Available El presente estudio se realizó en la Reserva Forestal Municipal de Cogua (Cundinamarca, Colombia, como parte del proyecto “Hacia un modelo de restauración del bosque”. Tiene como objetivos caracterizar el borde de avance del bosque, dominado por la especie Chusquea scandens y evaluar la regeneración de especies luego de disturbios experimentales a lo largo del borde de bosque. Con el primero se generó información preliminar del estado del borde de avance y del potencial que puede existir allí para la regeneración natural de la vegetación, el muestreo se realizó entre los meses de julio y octubre de 2003, en el cual se evaluaron algunas condiciones bióticas, abióticas y edáficas por medio del método línea intercepto a lo largo del gradiente pastizal-chuscal-bosque. El segundo estableció que tipo de disturbios son favorables para activar y potencializar la regeneración en los bordes de avance dominados por el chusque, los disturbios se basaron en reducir la competencia que hace el chusque por luz, así como también aumentar la disponibilidad de espacio para el establecimiento de otras especies. Para la caracterización del borde de avance se obtuvo que hacia el pastizal el chusque presenta una
    alta densidad que genera una zona de difícil acceso, lo cual puede funcionar como una barrera natural que reduce la influencia de especies de áreas abiertas en el interior del borde de avance, en donde se presentan peque��os claros donde el chuscal se reduce y se muestra una regeneración natural de especies. Además se estableció que a altas densidades del chusque se reducen las posibilidades de regeneración natural y la implantación de especies arbóreas, así como también, que la regeneración presentada hacia el interior del borde de avance está dominada por especies de borde y de bosque, siendo las herbáceas, enredaderas y arbustos las formas de crecimiento más importantes. Luego de los disturbios experimentales se

  7. El proceso enseñanza-aprendizaje de las Ciencias experimentales en una comunidad de aprendizaje

    OpenAIRE

    Ortega Quevedo, Vanessa

    2016-01-01

    La finalidad de este estudio es analizar el proceso de enseñanza-aprendizaje de las Ciencias Experimentales en una comunidad de aprendizaje. Para ello, se ha realizado una pequeña investigación sobre cómo profesores de un centro que ostenta el cargo de Comunidad de Aprendizaje trabajan las ciencias. Además, diseñan y llevan a la práctica una intervención que fusiona los modelos didácticos más usuales en la enseñanza de las Ciencias Experimentales, con la concepción comunicativa de la enseñanz...

  8. Ciencias Experimentales en la Educación Infantil y en la Educación Primaria

    OpenAIRE

    Naves Pineda, Francisco Javier; Feliu Ortega, María José; Fernández-Lorenzo, Concepción

    2010-01-01

    Este curso engloba los conocimientos básicos que deben ser adquiridos por los alumnos en los grados de Magisterio en Educación Infantil y en Educación Primaria sobre las Ciencias Experimentales. De esta forma, se desarrollan temas que versan sobre la materia, la energía, la luz, los estados de agregación de la materia, etc, y se incluyen los conocimientos sobre el entorno que nos rodea desde un punto de vista físico y químico.

  9. Short-term effects of habitat fragmentation on the abundance and species richness of beetles in experimental alfalfa micro-landscapes Efectos a corto plazo de la fragmentación del hábitat sobre la abundancia y riqueza de especies de coleópteros en micro-paisajes experimentales de alfalfa

    Directory of Open Access Journals (Sweden)

    AUDREY A. GREZ

    2004-09-01

    , instead, it could favor the biota, at least at short time scalesLa pérdida y fragmentación del hábitat han sido consideradas como las principales causas de la disminución de biodiversidad. La pérdida de hábitat es una disminución del hábitat utilizable por los organismos y la fragmentación es un cambio en la configuración espacial del paisaje, donde los fragmentos remanentes quedan relativamente aislados entre sí. Trabajos teóricos recientes indican que los efectos de la pérdida de hábitat son más importantes que los de la fragmentación, sin embargo existen pocos estudios experimentales que evalúen por separado ambos procesos. Para estudiar los efectos de la fragmentación per se sobre la abundancia y riqueza de especies de coleópteros epigeos, se crearon 15 micro-paisajes de alfalfa de 30 x 30 m distribuidos en tres bloques. Doce de ellos se fragmentaron removiendo el 84 % del hábitat, dejando cuatro ó 16 fragmentos separados por 2 ó 6 m. Entre diciembre del 2002 y abril del 2003, antes y después de la fragmentación, se muestrearon los coleópteros mediante trampas Barber. Se capturó un total de 8.074 coleópteros de 75 especies pertenecientes a 16 familias. El tipo de paisaje no afectó la abundancia de coleópteros, sólo Anthicidae fue más abundante en los paisajes de 4 fragmentos separados por 2 m y fue más abundante en la matriz. El resto de de las familias fue más abundante en los fragmentos, significativamente Carabidae y Lathridiidae. La riqueza de especies por trampa y por paisaje fue mayor en los paisajes con 16 fragmentos separados por 6 m, concentrándose en los fragmentos. Contrario a lo descrito en la mayor parte de la literatura, la fragmentación no afectó negativamente la abundancia y riqueza de especies de coleópteros epigeos asociados a alfalfa. Más bien, fragmentos de alfalfa más pequeños y aislados ofrecieron un refugio de hábitat para la biodiversidad de coleópteros epigeos. Estos resultados concuerdan con los

  10. Laser shocks on helium, hydrogen and diamond: an experimental study of the warm dense matter zone; Chocs laser sur l'helium, l'hydrogene et le diamant: une etude experimentale de la 'Warm Dense Matter'

    Energy Technology Data Exchange (ETDEWEB)

    Brygoo, St

    2006-11-15

    The purpose of this work was to develop a new approach of laser shocks on pre-compressed targets in order to collect data concerning the equation of state in the warm dense matter zone of the phase diagram. The accuracy of the measurement has been increased by the use of a new metrology based on quartz. Quartz is considered as a standard for the measurement of both the pressure and the density, a model of an isentropic relaxation based on a Grueneisen type approximation has been developed. By combining laser shocks with diamond anvil cells and by using this new metrology, we have investigated the following systems: diamond, helium, hydrogen, deuterium and hydrogen-helium mixtures. The results for helium agree very well with the predictions of the Saumon-Chabrier model. The results for deuterium are consistent with the latest results found in literature. As for the results concerning hydrogen, they have showed the limits of the quartz-based metrology. In fact, by being so little dense we are at the limit of the application range of the quartz relaxation. A mixture of helium-hydrogen (50 %) has been investigated, no sign of phase separation has been found.

  11. Investigaciones sobre la influencia del factor de forma y del rozamiento en procesos de compresión de piezas cilíndricas de aleación de aluminio AA 6082-T6 mediante técnicas numéricas y experimentales

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    Marín, M. M.

    2013-06-01

    Full Text Available The material characterization under similar load conditions to those applied during manufacturing is important in order to analyse Bulk Forming Compression Processes from a more realistic point of view. Open die forging of AA 6082-T6 aluminum alloy has been analysed by using experimental techniques and Finite Elements Method (FEM. The influence of the workpiece geometry on the effects that friction produces in typical process variables such as applied forces, contact pressures and stresses and strains in workpieces has been analysed by FEM simulation. It has been shown that higher shape factors of the initial workpiece geometry are recommended in such a way that friction effect is minimised. These results are interesting in order to decrease the required energy of the process and the tool wear, and could be used in further analysis of stamping processes.La caracterización de los materiales bajo similares condiciones de carga a las que se tienen durante su fabricación permite abordar el estudio de Procesos de Conformado por Deformación Plástica a Compresión (PCDPC desde un punto de vista más realista. La forja abierta de la aleación de aluminio AA 6082-T6 ha sido sometida a análisis, combinando técnicas experimentales y el Método de los Elementos Finitos (MEF. A través del modelo numérico se ha analizado la influencia de la geometría de la pieza en los efectos que el rozamiento provoca en variables típicas de estos procesos como las presiones aplicadas, presiones de contacto y tensiones y deformaciones en las piezas. Se ha demostrado que se debe elegir una geometría de pieza inicial con un factor de forma lo más elevado posible para minimizar el efecto del rozamiento. Estos resultados son de interés para disminuir la energía requerida en el proceso así como el desgaste de herramientas y podrían extrapolarse a procesos como la estampación.

  12. Experimental study of hot electrons propagation and energy deposition in solid or laser-shock compressed targets: applications to fast igniter; Etude experimentale de la propagation et du depot d'energie d'electrons rapides dans une cible solide ou comprimee par choc laser: application a l'allumeur rapide

    Energy Technology Data Exchange (ETDEWEB)

    Pisani, F

    2000-02-15

    In the fast igniter scheme, a recent approach proposed for the inertial confinement fusion, the idea is to dissociate the fuel ignition phase from its compression. The ignition phase would be then achieved by means of an external energy source: a fast electron beam generated by the interaction with an ultra-intense laser. The main goal of this work is to study the mechanisms of the hot electron energy transfer to the compressed fuel. We intent in particular to study the role of the electric and collisional effects involved in the hot electron propagation in a medium with properties similar to the compressed fuel. We carried out two experiments, one at the Vulcan laser facility (England) and the second one at the new LULI 100 TW laser (France). During the first experiment, we obtained the first results on the hot electron propagation in a dense and hot plasma. The innovating aspect of this work was in particular the use of the laser-shock technique to generate high pressures, allowing the strongly correlated and degenerated plasma to be created. The role of the electric and magnetic effects due to the space charge associated with the fast electron beam has been investigated in the second experiment. Here we studied the propagation in materials with different electrical characteristics: an insulator and a conductor. The analysis of the results showed that only by taking into account simultaneously the two propagation mechanisms (collisions and electric effects) a correct treatment of the energy deposition is possible. We also showed the importance of taking into account the induced modifications due to the electrons beam crossing the target, especially the induced heating. (author)

  13. Efecto del estrés hídrico sobre la germinación de genotipos de frijol común en condiciones experimentales de sequía. Effect of water stress during germination period of common bean in experimental conditions of drought

    OpenAIRE

    Amalia Domínguez Suárez; Yunel Pérez Hernández; Maryla Sosa del Castillo; Daynet Sosa del Castillo; Ramón Rea Suárez

    2014-01-01

    El frijil común, Phaseolus vulgaris L., es la leguminosa alimenticia mas cultivada en América Latina pero a menudo es expuesta a condiciones no favorables y poco uso de insumos. El estrés hídrico es considerado la condición más común y desfavorable para los cultivos, por tal motivo se estudió el efecto del estrés hídrico en el periodo de germinación de genotipos  de Phaseolus vulgaris L cultivadas  en Cuba. Las semillas de frijol fueron colocadas a germinar en frascos, sobre papel filtro. Par...

  14. Inferencias sobre Grafos

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    Sira M. Allende

    2002-05-01

    Full Text Available El estudio de un juego puede ser modelado asumiendo que solo algunas partidas son observadas. Entonces el árbol del juego debe ser estimado utilizando información muestral. Similarmente ocurre al obtener información sobre el comportamiento de las decisiones tomadas por individuos muestreados sobre un árbol de decisión teórico. Al considerar una medida de probabilidad que caracterice el comportamiento de redes aleatorias se puede obtener un estimado del árbol asociado. Este problema es el analizado en este trabajo. Algunos resultados experimentales obtenidos usando Recocido Simulado ilustran el procedimiento. Su papel en el estudio de modelos económicos y de mercadeo es discutido.

  15. Cardiogenic shock

    Science.gov (United States)

    Shock - cardiogenic ... electrical system of the heart (heart block) Cardiogenic shock occurs when the heart is unable to pump ... orthostatic hypotension) Weak (thready) pulse To diagnose cardiogenic shock, a catheter (tube) may be placed in the ...

  16. Inmunogenicidad de la vacuna cubana recombinante heberbiovac HB en modelos experimentales y aplicados al humano

    National Research Council Canada - National Science Library

    González Ramírez, Victoria Esther; González Griego, Antonio; Ramírez Albajés, Victoria; Alerm González, Alina

    2000-01-01

    ... la utilización de la vacuna de producción cubana contra la hepatitis B. Se desarrollaron modelos experimentales y aplicados al humano que permitieron el estudio de inmunogenicidad mediante distintas...

  17. ENFERMEDAD DE HUNTINGTON: MODELOS EXPERIMENTALES Y PERSPECTIVAS TERAPÉUTICAS

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    TERESA SERRANO SÁNCHEZ

    2011-01-01

    Full Text Available La enfermedad de Huntington (EH es un trastorno degenerativo de Weiss de origen hereditario. Hasta el momento no existe un tratamiento efectivo para la enfermedad que inexorablemente después de transcurridos 15 a 20 años, evoluciona hacia incapa- cidad total o muerte. En este trabajo se revisan las características clínicas y morfológicas de la EH y los modelos experimentales más utilizados para su estudio tomando como fuente, artículos indexados en la base de datos Medline publicados en los últimos 20 años. Se valoran las ventajas y desventajas de estos modelos y su perspectiva para el desarrollo de ensayos clínicos. El consenso de lo reportado plantea que de los modelos tóxicos, los inducidos por neurotoxinas tales como ácido quinolínico parecen ser los más adecuados para reproducir las características neuropatológicas, y por otro lado los modelos genéticos contribuyen con más evidencias al conocimiento del origen etiológico de la enfermedad. Numerosos tratamientos han sido aplicados en el manejo de las manifestaciones clínicas que aparecen en EH, sin poder detener o disminuir las afectaciones que derivan de la pérdida neuronal. La sintomatología clínica ha sido posible reproducirla, al menos en parte, en animales de experimentación lo que ha per- mitido realizar ensayos terapéuticos. Desde el punto de vista de tratamiento, lo que más promisorio parece ser, la terapia celular con células provenientes de diferentes fuentes y dentro de ellas las no neurales, que implican menor censura ética y mayor factibilidad de obtención para la aplicación en los enfermos. Por otro lado el desarrollo de la tecnología del ARN de interferencia, emerge como una herramienta terapéutica potencial para el tratamiento de EH, así como para responder interrogantes básicas relacionadas con el desarrollo de la enfermedad.

  18. Aplicación del Programa Microsoft Excel para resolver problemas experimentales de Física

    OpenAIRE

    Dania Cuenca Rodríguez; Ronal Tamayo Cuenca; Jorge Tamayo Pupo

    2010-01-01

    Se abordaron las principales aplicaciones de las hojas electrónicas de cálculo del programa Microsoft Excel para la solución de problemas experimentales de Física. Contiene los fundamentos teóricos y prácticos para su uso, con énfasis en el sistema de acciones e operaciones experimentales que pueden ser auxiliadas con la aplicación del Excel y se describe la experiencia de los autores en el desarrollo de las prácticas de laboratorio de Física en las carreras de ingeniería de la Universidad de...

  19. Traumatic shock: the fifth shock.

    Science.gov (United States)

    Anderson, Maighdlin W; Watson, Gregory A

    2013-01-01

    Although, historically, shock associated with traumatic injury has been evaluated through knowledge of the 4 recognized shock patterns--cardiogenic, obstructive, distributive, and hypovolemic--many trauma practitioners view traumatic shock as a unique fifth shock pattern. Although secondary to a systemic inflammatory response syndrome triggered by endogenous danger signals, traumatic shock represents a unique pathological condition that begins with multiple, usually blunt, trauma and may conclude with multiple organ dysfunction syndrome and death. While varying mechanisms of injury may lead to different presentations of shock and cardiovascular decompensation, a unifying theme of traumatic shock is an overwhelming inflammatory response driven by proinflammatory cytokines, and the downstream results of this cytokine storm including, but not limited to, acute respiratory distress syndrome, coagulopathy, sepsis, and multiple organ dysfunction syndrome. Treatment is primarily supportive; however, research into novel therapeutics for traumatic shock is ongoing and promises some direction for future care.

  20. Sucesiones experimentales en pastizales con diferente uso y edad de abandono

    Directory of Open Access Journals (Sweden)

    Vargas Ríos Orlando

    2006-06-01

    Full Text Available Se presentan los resultados de la diversidad y cobertura de las especies vegetales presentes en parcelas después
    de generar disturbios experimentales (remoción epígea y remoción epígea-hipógea, en dos pastizales con diferente
    uso y edad de abandono, en la Reserva Forestal Municipal de Cogua, Cundinamarca (Colombia. Se observaron
    diferencias significativas entre los tratamientos y los pastizales en cuanto a diversidad y cobertura de las especies, dado el comportamiento diferencial de las especies a los disturbios experimentales realizados. En
    las parcelas con remoción epígea se obtuvo una regeneración rápida de la cobertura vegetal, con una composición de especies similar a la presentada antes de los disturbios experimentales. En los tratamientos con
    remoción epígea-hipógea la regeneración de la vegetación y el aumento de la cobertura es lento pero con un
    aumento en la diversidad con respecto a las especies presentes antes de los disturbios experimentales.

  1. La conformación del cáncer como objeto científico y problema sanitario en la Argentina: discursos, prácticas experimentales e iniciativas institucionales, 1903-1922

    OpenAIRE

    Buschini, José D.

    2014-01-01

    El trabajo analiza la conformación del cáncer como problema sanitario y como objeto científico en la Argentina en las dos primeras décadas del siglo XX. Se consideran la adquisición y circulación de conocimientos foráneos sobre el tema, el contexto en el que surgieron los primeros desarrollos experimentales, las iniciativas institucionales promovidas desde la profesión médica y el modo en que se logró interesar a las autoridades estatales y a la sociedad civil para darles curso. Se estudia de...

  2. Estadísticos poblacionales de Triatoma sordida Stäl 1859 (Hemiptera : Reduviidae en condiciones experimentales

    Directory of Open Access Journals (Sweden)

    Oscherov Elena B.

    1996-01-01

    Full Text Available Se realizó el seguimiento longitudinal de cuatro cohortes de 100 huevos cada una. Los insectos fueron criados a 28°C ± 3°C y 63 % ± 10% de humedad relativa, y alimentados cada siete días sobre gallina (Gallus domesticus, durante 40 min. Las cohortes fueron controladas una vez por semana. Se observó un valor constante de supervivencia en las cuatro cohortes, sin picos importantes. La expectativa de vida de los machos, en promedio, fue de 37,4 semanas y la de las hembras 36,8. El tiempo generacional demandó 61,7 semanas. La tasa reproductiva neta indica que esta población se incrementará 143,3 veces con cada generación. La tasa intrínseca de crecimiento natural fue de 0,082 por semana. El máximo valor reproductivo se verificó, en promedio, a la tercer semana del ingreso al estado adulto. La distribución estable de edades de T. sordida sería de 32% huevos, 26% ninfas de primer estadio, 19% ninfas de segundo estadio, 13% ninfas de tercer estadio, 6% ninfas de cuarto estadio, 3% ninfas de quinto estadio y 1% de adultos. Es la primera cita para Argentina sobre la tabla de vida de T. sordida. El análisis de estos parámetros permite considerar que esta especie se comporta como "K estratega", en condiciones experimentales.

  3. What Causes Cardiogenic Shock?

    Science.gov (United States)

    ... Home / Shock Cardiogenic Shock Causes Immediate Causes Cardiogenic shock occurs if the ... is cardiogenic shock. Tests and Procedures To Diagnose Shock and Its Underlying Causes Blood Pressure Test Medical ...

  4. What Is Cardiogenic Shock?

    Science.gov (United States)

    ... Home / Shock Cardiogenic Shock Causes Immediate Causes Cardiogenic shock occurs if the ... is cardiogenic shock. Tests and Procedures To Diagnose Shock and Its Underlying Causes Blood Pressure Test Medical ...

  5. Las ciencias experimentales en Educación Infantil. "El huerto escolar".

    OpenAIRE

    García Cordovilla, Irene

    2016-01-01

    La finalidad de este trabajo es incorporar las ciencias experimentales en el aula de Educación Infantil de una manera amena teniendo en cuenta las inquietudes e intereses de los alumnos de esta etapa educativa. A través de la metodología por proyectos tenemos la oportunidad de desarrollar el pensamiento crítico de nuestros alumnos Grado en Educación Infantil

  6. Septic Shock

    Science.gov (United States)

    Seymour, Christopher W.; Rosengart, Matthew R.

    2015-01-01

    IMPORTANCE Septic shock is a clinical emergency that occurs in more than 230 000 US patients each year. OBSERVATIONS AND ADVANCES In the setting of suspected or documented infection, septic shock is typically defined in a clinical setting by low systolic (≤90 mm Hg) or mean arterial blood pressure (≤65 mm Hg) accompanied by signs of hypoperfusion (eg, oliguria, hyperlactemia, poor peripheral perfusion, or altered mental status). Focused ultrasonography is recommended for the prompt recognition of complicating physiology (eg, hypovolemia or cardiogenic shock), while invasive hemodynamic monitoring is recommended only for select patients. In septic shock, 3 randomized clinical trials demonstrate that protocolized care offers little advantage compared with management without a protocol. Hydroxyethyl starch is no longer recommended, and debate continues about the role of various crystalloid solutions and albumin. CONCLUSIONS AND RELEVANCE The prompt diagnosis of septic shock begins with obtainment of medical history and performance of a physical examination for signs and symptoms of infection and may require focused ultrasonography to recognize more complex physiologic manifestations of shock. Clinicians should understand the importance of prompt administration of intravenous fluids and vasoactive medications aimed at restoring adequate circulation, and the limitations of protocol-based therapy, as guided by recent evidence. PMID:26284722

  7. Gestión de Materiales Experimentales y su Uso en Replicaciones de Experimentos: Un Mapeo Sistemático de la Literatura

    Directory of Open Access Journals (Sweden)

    Edison Espinosa

    2016-11-01

    Full Text Available La Ingeniería de Software Experimental (ISE aplica la experimentación para obtener conocimiento sobre productos, métodos, técnicas usados en el proceso de desarrollo software. Para validar el conocimiento es necesario repetir el experimento original tantas veces como sea necesario. Se requieren mucha información y materiales acerca del experimento para que un experimentador realice una replicación. Previa a la ejecución de la replicación del experimento, algunos o la totalidad de los materiales pueden requerir cambios produciendo nuevas o modificadas versiones de estos. Una vez ejecutada la replicación del experimento se espera que, parte o la totalidad de los materiales, se incorporen al material del experimento original. El incremento en el número de replicaciones del experimento original está directamente relacionado con el incremento de las versiones del material experimental, que ocasiona comúnmente confusión y desorden en su organización. En este trabajo, realizamos un mapeo sistemático de la literatura (MSL para localizar trabajos sobre Gestión de Materiales Experimentales y su Uso en Replicaciones en Ingeniería de Software Experimental. Los resultados encontrados reflejan la escasa existencia de artículos sobre esta temática. Además, el análisis de los estudios encontrados ha descubierto que dichos artículos, en su mayoría, adolecen de problemas en la gestión de versiones de materiales experimentales para poder llevar a cabo un proceso de replicación. Estos datos proporcionan información de interés para iniciar la investigación de la adopción del paradigma de gestión de configuración de software en la gestión del material experimental en ISE.

  8. Aplicación práctica de métodos estereológicos renales en modelos animales experimentales

    Directory of Open Access Journals (Sweden)

    María Teresa Fernández García

    2017-01-01

    Full Text Available Los riñones son órganos vitales que realizan funciones de excreción, equilibrio hidroelectrolítico y producción de hormonas. La nefrona es su unidad estructural y funcional. El número, tamaño y distribución de los componentes de la nefrona contienen información relevante sobre la función renal. La estereología es una rama de la morfometría que permite, aplicando reglas matemáticas, obtener información tridimensional de estructuras biológicas a partir de cortes microscópicos bidimensionales, seriados, paralelos y equidistantes. Ante la complejidad de los estudios estereológicos y la carencia de una bibliografía clara sobre el desarrollo de los mismos, el objetivo de este trabajo es explicar de forma sencilla y con ejemplos, utilizando un modelo animal, los conceptos básicos de estereología, así como el cálculo de los principales parámetros estereológicos renales y que estos puedan ser aplicados en futuros estudios experimentales.

  9. Análisis conductual aplicado en neuropsicología: fundamentos teóricos, experimentales y empíricos.

    Directory of Open Access Journals (Sweden)

    José Alonso Aguilar-Valera

    2016-01-01

    Full Text Available El presente artículo presenta una revisión teórica donde se expone la importancia que tienen los principios y técnicas conductuales dentro del ámbito de la rehabilitación neuropsicológica. En la intervención clínica con pacientes víctimas de disfunción, daño o deterioro neurológico, donde las consecuencias directas sobre el comportamiento son significativas, el uso de las estrategias provenientes de las técnicas de modificación de conducta (conductuales y/o conductual-cognitivas son importantes para el tratamiento de los diversos síndromes neuroconductuales, estando dentro de las competencias del especialista en esta área aplicada de las neurociencias. Además de describirse tanto aspectos teóricos como experimentales de principal relevancia para estos fines, también se mencionarán algunos estudios empíricos llevados a cabo, bajo una metodología de caso único, para una mejor comprensión sobre la utilidad aplicativa de los principios conductuales en el ámbito de la neuropsicología clínica.

  10. [Obstructive shock].

    Science.gov (United States)

    Pich, H; Heller, A R

    2015-05-01

    An acute obstruction of blood flow in central vessels of the systemic or pulmonary circulation causes the clinical symptoms of shock accompanied by disturbances of consciousness, centralization, oliguria, hypotension and tachycardia. In the case of an acute pulmonary embolism an intravascular occlusion results in an acute increase of the right ventricular afterload. In the case of a tension pneumothorax, an obstruction of the blood vessels supplying the heart is caused by an increase in extravascular pressure. From a hemodynamic viewpoint circulatory shock caused by obstruction is closely followed by cardiac deterioration; however, etiological and therapeutic options necessitate demarcation of cardiac from non-cardiac obstructive causes. The high dynamics of this potentially life-threatening condition is a hallmark of all types of obstructive shock. This requires an expeditious and purposeful diagnosis and a rapid and well-aimed therapy.

  11. Toxic shock syndrome

    Science.gov (United States)

    Staphylococcal toxic shock syndrome; Toxic shock-like syndrome; TSLS ... Toxic shock syndrome is caused by a toxin produced by some types of staphylococcus bacteria. A similar problem, called toxic shock- ...

  12. Ciencias Experimentales en el aula de Educación Infantil

    OpenAIRE

    Zamalloa Echevarría, Teresa

    2013-01-01

    Duración (en horas): Más de 50 horas, Destinatario: Estudiante Mediante la metodología de ABP el alumnado de tercer curso del grado de Educación infantil elaborará propuestas didácticas en grupos para el estudio de los contenidos de ciencias experimentales empleando diferentes estrategias y recursos didácticos para la enseñanza/aprendizaje del medio físico y natural en Educación Infantil.

  13. INFLUENCIA DE DIFERENTES VARIABLES EXPERIMENTALES EN LA COMPOSICIÓN DEL COMPLEJO DE BIOFLAVONOIDES DEL LIMÓN (CBL)

    OpenAIRE

    O. Cartaya; Inés Reynaldo; Clara Nogueiras

    2002-01-01

    En este trabajo se estudió la influencia de las variables experimentales: proporción (m/v) residuo/agua, la temperatura y el tiempo de extracción en el rendimiento y la composición del CBL a través de un diseño experimental factorial 23. Para cada experiencia se evaluó el rendimiento, el contenido de azúcares totales y reductores, la concentración de flavonoides totales y la acidez total, evidenciándose la relación que existe entre las variables evaluadas y las condiciones experimentales sele...

  14. Shock Waves

    CERN Document Server

    Jiang, Z

    2005-01-01

    The International Symposium on Shock Waves (ISSW) is a well established series of conferences held every two years in a different location. A unique feature of the ISSW is the emphasis on bridging the gap between physicists and engineers working in fields as different as gas dynamics, fluid mechanics and materials sciences. The main results presented at these meetings constitute valuable proceedings that offer anyone working in this field an authoritative and comprehensive source of reference.

  15. Patrones iniciales de sucesión en claros experimentales de plantaciones de Pinus patula en el Embalse de Chisacá, Usme, Cundinamarca (Colombia

    Directory of Open Access Journals (Sweden)

    Vargas Ríos Orlando

    2006-06-01

    Full Text Available Se presenta un estudio que determina el efecto de la creación de claros experimentales con diferentes densidades sobre los patrones iniciales de sucesión dentro de plantaciones de Pinus patula. Adicionalmente, se evaluó el efecto de la remoción de acículas del suelo. Antes del establecimiento de los claros ya se encontraban en las parcelas la mayoría de las especies (30, pero en muy baja proporción; luego del aclareo, se registraron
    25 especies determinadas entre plantas vasculares (20 y no vasculares (5; 13 de éstas resultaron de mayor relevancia debido a su mayor cobertura en las parcelas. Se pudo establecer que la apertura de claros, además de la mayor disponibilidad de luz solar, permite una mayor entrada de agua, con lo cual se estimula la germinación, crecimiento y establecimiento de individuos relativamente rápido. Se determinó que existe un banco de semillas dentro de las acículas del suelo. Es importante continuar con el monitoreo de las parcelas para un mejor entendimiento del fenómeno sucesional que ocurre.

  16. Evaluación del efecto de dietas artificiales experimentales en el rendimiento reproductivo de penaeus vannamei

    OpenAIRE

    Espín, Marcos

    2000-01-01

    Evaluación del Efecto de Dietas Artificiales Experimentales en el Rendimiento Reproductivo de Penaeus vannamei Dos ensayos nutricionales a escala comercial fueron realizados para comprobar el efecto de la utilización de dietas artificiales y la sustitución parcial de los alimentos frescos en el rendimiento reproductivo de Penaeus vannamei.

  17. Base de datos sobre necesidades hídricas

    OpenAIRE

    Felicita González Robaina; Julián Herrera Puebla; Osmany Hernández Barreto; Teresa López Seijas; Greco Cid Lazo

    2012-01-01

    El ordenamiento y accesibilidad a la información sobre régimen hídrico de los principales cultivos agrícolas resulta de gran impacto económico social ya que la misma permite la definición de la función agua rendimiento y la productividad del agua como herramientas eficientes en el planeamiento, diseño y operación del suministro de agua a los cultivos. Este trabajo se trazó como objetivo obtener a partir de la recopilación y tabulación de los resultados experimentales existentes en el Institut...

  18. Las Ciencias experimentales en el aula de Educación Infantil: El ciclo del agua

    OpenAIRE

    Ribera Morán, María

    2014-01-01

    Este proyecto se basa en el ciclo de agua en relación a las ciencias experimentales, y enfocado al tercer curso del segundo ciclo de Educación Infantil, con alumnos de 5 a 6 años. En él se expondrán los diferentes autores que han dado lugar a este tipo de pedagogía activa, la metodología que se llevará a cabo, los objetivos que deberán alcanzar los alumnos, la programación y los procesos de evaluación que se pretenden, así como un apéndice con las actividades detalladas. Grado en Educación...

  19. INCLUSIÓN DE HIBISCUS SABDARIFFA EN ALIMENTOS EXPERIMENTALES PARA MACROBRACHIUM TENELLUM: EFECTOS EN LA PIGMENTACIÓN, CRECIMIENTO Y SUPERVIVENCIA.

    Directory of Open Access Journals (Sweden)

    Martín A. Aréchiga P.

    2015-01-01

    Full Text Available En la naturaleza, los pigmentos tienen la principal función de colorear; sin embargo, también tienen efectos sobre el estado de salud y desarrollo de los organismos. Los compuestos sintéticos dirigidos a incrementar la coloración en organismos con importancia comercial, representan entre el 15 al 20% del costo de la dieta. Por lo anterior, la investigación sobre pigmentos de origen natural (más baratos y menos tóxicos se ha incrementado sustancialmente en los últimos años. Las antocianinas pueden ser utilizadas como una alternativa para la pigmentación de organismos. En este estudio se utilizaron los cálices de Hibiscus sabdariffa, planta popular que acumula antocianinas que proporciona su característico color rojo. Langostinos Macrobrachium tenellum fueron alimentados con dietas que incluían cálices de H. sabdariffa (jamaica bajo los siguientes tratamientos: i pigmento extraído con agua, ii pigmento extraído con etanol acidificado [0.1 M HCl (v/v], y iii harina de cálices. El efecto pigmentante de las dietas experimentales se comparó con langostinos sometidos a una dieta control sin pigmentos añadidos y con langostinos extraídos del medio silvestre. Los langostinos alimentados con la dieta de inclusión de polvo de jamaica mostraron la mayor expresión de eritróforos (color rojo en el exoesqueleto del pleon (abdomen y ganancia en longitud y peso, después de 60 días. Estos resultados sugieren que H. sabdariffa puede ser utilizado como complemento alimenticio natural, puesto que tiene un efecto positivo en los parámetros de crecimiento y pigmentación.

  20. Geometrical shock dynamics of fast magnetohydrodynamic shocks

    Science.gov (United States)

    Mostert, Wouter; Pullin, Dale I.; Samtaney, Ravi; Wheatley, Vincent

    2016-11-01

    We extend the theory of geometrical shock dynamics (GSD, Whitham 1958), to two-dimensional fast magnetohydrodynamic (MHD) shocks moving in the presence of nonuniform magnetic fields of general orientation and strength. The resulting generalized area-Mach number rule is adapted to MHD shocks moving in two spatial dimensions. A partially-spectral numerical scheme developed from that of Schwendeman (1993) is described. This is applied to the stability of plane MHD fast shocks moving into a quiescent medium containing a uniform magnetic field whose field lines are inclined to the plane-shock normal. In particular, we consider the time taken for an initially planar shock subject to an initial perturbed magnetosonic Mach number distribution, to first form shock-shocks. Supported by KAUST OCRF Award No. URF/1/2162-01.

  1. Localized shocks

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Daniel A. [Center for Theoretical Physics and Department of Physics,Massachusetts Institute of Technology, Cambridge, MA (United States); Stanford, Douglas [Stanford Institute for Theoretical Physics and Department of Physics,Stanford University, Stanford, CA (United States); School of Natural Sciences, Institute for Advanced Study,Princeton, NJ (United States); Susskind, Leonard [Stanford Institute for Theoretical Physics and Department of Physics,Stanford University, Stanford, CA (United States)

    2015-03-10

    We study products of precursors of spatially local operators, W{sub x{sub n}}(t{sub n})…W{sub x{sub 1}}(t{sub 1}), where W{sub x}(t)=e{sup −iHt}W{sub x}e{sup iHt}. Using chaotic spin-chain numerics and gauge/gravity duality, we show that a single precursor fills a spatial region that grows linearly in t. In a lattice system, products of such operators can be represented using tensor networks. In gauge/gravity duality, they are related to Einstein-Rosen bridges supported by localized shock waves. We find a geometrical correspondence between these two descriptions, generalizing earlier work in the spatially homogeneous case.

  2. Efectos de las instrucciones audiovisuales no explícitas sobre el comportamiento alimentario

    OpenAIRE

    Hortencia Alicia Barrera Pelayo; Antonio López-Espinoza; Alma Gabriela Martínez; Carolina De La Torre-Ibarra; Virginia Aguilera; Alma Galindo; Felipe Díaz; Karina Franco; Claudia R. Magaña

    2010-01-01

    Este estudio evaluó los efectos de las instrucciones no explícitas sobre la conducta alimentaria. Participaron cinco jóvenes entre los 19 y 24 años, a quienes se les observó durante dos fases experimentales a dos tipos de alimento nutricional (fruta y agua) y no nutricional (papas fritas y refresco). Los participantes fueron f lmados en dos programas de video. En la primera fase se grabaron videos musicales y en la segunda, un documental sobre hábitos alimentarios saludables. Los resultados m...

  3. Consideraciones sobre la filantropía y la crítica literaria

    Directory of Open Access Journals (Sweden)

    Jorge Zalamea

    1964-11-01

    Full Text Available Voy a tratar de plantear aquí algunas graves cuestiones, no debatidas hasta ahora en Colombia aunque tengan una influencia cada día más amplia y más perniciosas consecuencias sobre el desarrollo de la cultura nacional. Son, desde luego, puntos de vista muy personales pero que, como se verá luego, se presentan sobre bases científicas y pruebas experimentales. Tomadas las primeras de las tesis más recientes de la sociología norteamericana y extraídas las segundas de la realidad colombiana.

  4. Sobre el origen del código Genético

    OpenAIRE

    Fumiyoshi Watanabe; Michelle Robles; José A. García

    2007-01-01

    Existen ciertas evidencias experimentales que sugieren un mundo primitivo en el que la molécula de ácido ribonucleico (RNA) era la molécula responsable de codificar la información genética y de catalizar un número limitado de reacciones. En este "mundo de RNA" pudo darse el origen del código genético actual. En este manuscrito se presenta una breve discusión sobre las principales teorías que se han propuesto sobre el origen del código genético.

  5. Efecto protector de Helianthus annuus (girasol sobre el infarto de miocardio en conejos Nueva Zelanda

    Directory of Open Access Journals (Sweden)

    Edith Guardia-Espinoza

    Full Text Available Objetivos. Determinar el efecto protector del aceite de Helianthus annuus (Girasol sobre el infarto de miocardio inducido con epinefrina en conejos Nueva Zelanda. Materiales y métodos. Los conejos fueron asignados aleatoriamente en cinco grupos (n= 8 por grupo: blanco, control negativo, experimental 1 (10 mg/kg, experimental 2 (20 mg/kg y experimental 3 (40 mg/kg. Los grupos experimentales 1, 2 y 3 recibieron aceite de Helianthus annuus durante dos semanas. La epinefrina (2 mg/Kg se administró a los grupos control negativo, experimentales 1, 2 y 3 durante dos días consecutivos con un intervalo de 24 h después del pretratamiento con aceite. Veinticuatro horas después de la última administración, los conejos fueron anestesiados y sacrificados. Se evaluaron los niveles séricos de troponina I y número de polimorfonucleares por μm2. Resultados. Se encontró diferencia significativa entre el grupo control negativo y los grupos experimentales 1, 2 y 3 en los variables niveles séricos de troponina I y número de polimorfonucleares por μm2. Conclusiones: El aceite de Helianthus annuus a dosis de 20 mg/kg tiene efecto protector sobre el infarto de miocardio inducido con epinefrina en conejos Nueva Zelanda

  6. Efectos sobre la disposición sagital del raquis de un programa de Educación Postural en Educación Física de Primaria

    OpenAIRE

    Pilar Sainz de Baranda; Pedro Luis Rodríguez García; Fernando Santonja Medina

    2010-01-01

    El objetivo fue analizar el efecto de un programa de educación postural sobre el plano sagital de la columna vertebral. Un total de 80 escolares se dividieron en tres grupos (2 experimentales y 1 grupo control). Los grupos experimentales realizaron el programa de educación postural dentro de las clases de Educación Física de primaria durante un curso escolar completo (9 meses), dos sesiones por semana (31 semanas, 62 sesiones de Educación Física). El programa desarrollaba los contenidos de to...

  7. Collisionless electrostatic shocks

    DEFF Research Database (Denmark)

    Andersen, H.K.; Andersen, S.A.; Jensen, Vagn Orla

    1970-01-01

    An attempt was made in the laboratory to observe the standing collisionless electrostatic shocks in connection with the bow shock of the earth......An attempt was made in the laboratory to observe the standing collisionless electrostatic shocks in connection with the bow shock of the earth...

  8. Geometrical shock dynamics for magnetohydrodynamic fast shocks

    KAUST Repository

    Mostert, W.

    2016-12-12

    We describe a formulation of two-dimensional geometrical shock dynamics (GSD) suitable for ideal magnetohydrodynamic (MHD) fast shocks under magnetic fields of general strength and orientation. The resulting area–Mach-number–shock-angle relation is then incorporated into a numerical method using pseudospectral differentiation. The MHD-GSD model is verified by comparison with results from nonlinear finite-volume solution of the complete ideal MHD equations applied to a shock implosion flow in the presence of an oblique and spatially varying magnetic field ahead of the shock. Results from application of the MHD-GSD equations to the stability of fast MHD shocks in two dimensions are presented. It is shown that the time to formation of triple points for both perturbed MHD and gas-dynamic shocks increases as (Formula presented.), where (Formula presented.) is a measure of the initial Mach-number perturbation. Symmetry breaking in the MHD case is demonstrated. In cylindrical converging geometry, in the presence of an azimuthal field produced by a line current, the MHD shock behaves in the mean as in Pullin et al. (Phys. Fluids, vol. 26, 2014, 097103), but suffers a greater relative pressure fluctuation along the shock than the gas-dynamic shock. © 2016 Cambridge University Press

  9. Teor de cimento e seus efeitos sobre a resistência ao choque térmico de concretos espinelizados in-situ Cement content and the thermal shock performance of in-situ spinel formation in refractory castables

    Directory of Open Access Journals (Sweden)

    G. B. Cintra

    2008-12-01

    Full Text Available Concretos refratários aluminosos contendo espinélio são amplamente utilizados como revestimentos de panelas siderúrgicas, devido a sua elevada resistência à corrosão. Além do bom desempenho anti-corrosivo, estes materiais devem suportar as variações bruscas de temperatura causadas pela ciclagem térmica, responsáveis pela diminuição da vida útil do revestimento. Neste contexto, a análise da resistência ao dano por choque térmico se torna parâmetro fundamental para a correta seleção do revestimento refratário. Esta propriedade pode ser melhorada por meio da incorporação de mecanismos de tenacificação à estrutura do concreto. Uma fase que auxilia na tenacificação do material é o CA6, que está associada ao cimento de aluminato de cálcio (CAC, matéria-prima usada como ligante. Sendo assim, o objetivo deste trabalho é caracterizar o efeito do teor de cimento na microestrutura do concreto e suas conseqüências nos danos causados por choque térmico. Os resultados obtidos indicam que concretos com valores intermediários de cimento possuem melhor desempenho em relação ao choque térmico, nas temperaturas de uso das panelas. Dessa forma, o controle do teor de cimento possibilita aumentar a resistência ao dano por choque térmico e, consequentemente, a vida útil do revestimento.Spinel containing aluminous refractory castables are currently used in steel ladle due to their high corrosion resistance. Besides this property, these materials have to withstand sudden temperature variations caused by thermal cycling, which could be one of the main causes for shortening the lining's working life. Within this context, the thermal shock damage resistance analysis becomes a fundamental variable for the correct refractory selection. This property can be improved by toughening mechanisms, such as the presence of CA6, associated to calcium aluminate cement in the castable composition. Therefore, the objective of this work is to

  10. Sobre caudillos

    Directory of Open Access Journals (Sweden)

    Margarita Garrido

    1988-07-01

    Full Text Available Cuadro ensayos: De la respuesta criolla a los caudillos republicanos. Hispanoamérica 1750- 1850: Ensayos sobre la sociedad y el Estado. John Lynch. Universidad Nacional, Bogotá, 1987.

  11. Impacto actitudinal y canalización cognitiva de estereotipos sobre la inmigración a través de las noticias

    OpenAIRE

    JJ Igartua

    2013-01-01

    Introducción. Tomando como base la investigación sobre el efecto framing y la investigación sobre el tratamiento de la inmigración, se analizan los procesos de recepción e impacto de las noticias sobre actos delictivos. Metodología. Se realizaron dos investigaciones experimentales en donde los participantes fueron expuestos a una noticia y posteriormente cumplimentaron un cuestionario con escalas de auto-informe. Se manipularon la mención del origen nacional/geográfico de los protagonistas de...

  12. Fisiopatología del shock: Nuevas perspectivas

    Directory of Open Access Journals (Sweden)

    Miguel A. Jorge

    2011-10-01

    Full Text Available La actividad metabólica puede modificarse mediante la regulación de la población mitocondrial en distintas enfermedades críticas. A través de observaciones y ensayos clínicos examinamos esta adaptación metabólica en el shock cardiogénico, hemorrágico y séptico. La caída de la disponibilidad de O2 (DO2 llevaría a una reducción de la población mitocondrial y consecuentemente a una disminución del consumo de O2 (VO2. Esta secuencia permite atenuar y aun evitar la adquisición de una deuda de O2, considerada hasta hoy base fundamental de la fisiopatología del shock. El costo de esta adaptación mitocondrial es menor energía disponible y el déficit energético resultante ha sido relacionado con la falla orgánica múltiple (FOM, importante complicación de diversos procesos inflamatorios agudos y estados de shock. La FOM es mejor tolerada que el metabolismo anaeróbico y es potencialmente reversible si se revierten las causas desencadenantes y se reestablece el nivel energético por medio de la biogénesis mitocondrial.El desacople de la fosforilación oxidativa mitocondrial ocurre tanto en diversos modelos experimentales de shock como así también en el shock séptico en el hombre. Esta alteración mitocondrial puede ser detectada por un aumento desmesurado del VO2 en respuesta al incremento terapéutico de la DO2. Este aumento de la actividad metabólica puede ser equívocamente interpretado como la fase de repago de una deuda de O2.

  13. Biomass shock pretreatment

    Science.gov (United States)

    Holtzapple, Mark T.; Madison, Maxine Jones; Ramirez, Rocio Sierra; Deimund, Mark A.; Falls, Matthew; Dunkelman, John J.

    2014-07-01

    Methods and apparatus for treating biomass that may include introducing a biomass to a chamber; exposing the biomass in the chamber to a shock event to produce a shocked biomass; and transferring the shocked biomass from the chamber. In some aspects, the method may include pretreating the biomass with a chemical before introducing the biomass to the chamber and/or after transferring shocked biomass from the chamber.

  14. Efecto del pH en la adsorción de cadmio, niquel y zinc sobre una bentonita

    Directory of Open Access Journals (Sweden)

    Liz Adriana Pinilla Cuenca

    2010-09-01

    Full Text Available Se estudió el efecto del pH sobre la adsorción de cadmio, niquel y zinc, en solución acuosa a 25°C, sobre una bentonita colombiana proveniente del Valle del Cauca. Los datos experimentales se analizaron con base en las isotermas de adsorción, la constante termodinámica de reparto KDM (calculada mediante la isoterma de Langmuir, la relación de distribución Rd (obtenida del modelo Baeyens-Bradbury y una gráfica Kurbatov.

  15. Susceptibilidad a desinfectantes de Trichomonas vaginalis y Escherichia coli presentes en fómites experimentales

    Directory of Open Access Journals (Sweden)

    Fernando Anaya Velázquez

    2014-01-01

    Full Text Available Las enfermedades infecciosas provocadas por microorganismos patógenos se pueden transmitir directa o indirectamente. El protozoario Trichomonas vaginalis y la bacteria Escherichia coli son patógenos para el ser humano que pueden ser trans - mitidos por fómites. Existe una gama de productos para desinfectar, pero no existe información sobre el efecto completo de su eficacia en forma comparativa sobre bacterias o tricomonas en interacción con diferentes tipos de materiales. En este trabajo, se analizó el efecto de algunos desinfectantes sobre la viabilidad de Escherichia coli cepa 055 y Trichomonas vaginalis cepa GT-21, depositadas sobre diferentes tipos de materiales. Se diseñó un sistema in vitro con fómites experi - mentales para estudiar el efecto sobre estos patógenos. Se encontró que las tricomonas permanecen viables hasta ocho horas, y las bacterias hasta 24 horas en madera, papel, tela y plástico. Sin embargo, ambos microorganismos sobreviven solamente entre 1 y 4 horas sobre vidrio o metal. Tanto las bacterias como las tricomonas son inhibidas por los desinfec - tantes probados, siendo los más efectivos el etanol a 70% y el producto comercial Lysol ® .

  16. Etude theorique et experimentale des evaporateurs de dioxyde de carbone operant dans des conditions de givrage

    Science.gov (United States)

    Bendaoud, Adlane Larbi

    Les evaporateurs de refrigeration sont surtout du type tube a ailettes, appeles serpentins, et fonctionnent dans l'une des conditions suivantes: seche, humide ou avec formation de givre. Il a ete demontre que la formation du givre sur la paroi exterieure de l'echangeur engendre une surconsommation energetique a cause des operations de degivrage puisque 15 a 20% seulement de la chaleur produite sert au degivrage tandis que le reste est dissipee dans l'environnement [1]. Avec l'avenement des nouveaux refrigerants, moins nocifs envers l'environnement, l'industrie du froid se trouve penalisee du fait que peu ou pas de composantes mecaniques (compresseur, pompe, echangeur...etc.) adaptees sont disponibles [3]. Il s'agit pour la communaute des frigoristes de combler ce retard technologique en redeveloppant ces composantes mecaniques afin qu'elles soient adaptees aux nouveaux refrigerants. Dans cette optique, et afin de mieux comprendre le comportement thermique des evaporateurs au CO2 fonctionnant dans des conditions seches, qu'un groupe de chercheurs du CanmetENERGIE avaient lance, en 2000, un programme de R & D. Dans le cadre de programme un outil de simulation des evaporateurs au CO2 a ete developpe et un banc d'essai contenant une boucle secondaire de refrigeration utilisant le CO2 comme refrigerant a ete construit. Comme continuite de ce travail de recherche, en 2006 ce meme groupe de recherche a lance un nouveau projet qui consiste a faire une etude theorique et experimentale des evaporateurs au CO2 operants dans des conditions de givrage. Et, c'est exactement dans le cadre de ce projet que se positionne ce travail de these. Ce travail de recherche a ete entrepris pour mieux comprendre le comportement thermique et hydrodynamique des serpentins fonctionnant dans des conditions de givrage, l'effet des circuits de refrigerant ainsi que celui des parametres geometriques et d'operation. Pour cela, un travail theorique supporte par une etude experimentale a ete effectue

  17. Shocks in collisionless plasmas

    Science.gov (United States)

    Parks, G. K.; Lee, E.; Fu, S. Y.; Lin, N.; Liu, Y.; Yang, Z. W.

    2017-12-01

    The Earth's bow shock is the best-known collisionless shock in space. Although much is known about the bow shock, the mechanisms of heating and thermalization processes still remain poorly understood. Collisionless shocks are different from ordinary fluid shocks, because a fraction of the incident solar wind is reflected from the bow shock and the transmitted particles are not immediately thermalized. The reflected particles interact with the incident solar wind producing waves and instabilities that can heat and accelerate particles to high energies. Some of the waves can grow to large amplitudes such as Short Large Amplitude Magnetic Structures. Other upstream nonlinear structures include hot flow anomalies and density holes. The upstream nonlinear structures subsequently convect Earthward with the SW and could impact the structure and dynamics of the bow shock. These observations have clearly indicated that the upstream dynamics are an integral part of the bow shock system. Although much has been learned about the behavior of Earth's bow shock dynamics from the existing data, many fundamental questions remain not answered. This article will review observations of ion dynamics of Earth's bow shock system, what we have learned from recent and past observations. We provide new perspectives from multi-spacecraft Cluster observations about the spatial and temporal variations including the fundamental shock heating, acceleration, and entropy generation processes.

  18. Loxoscelismo en Chile: estudios epidemiológicos, clínicos y experimentales Loxoscelism in Chile: epidemiological, clinical and experimental studies

    Directory of Open Access Journals (Sweden)

    Hugo Schenone

    1989-12-01

    Full Text Available Se presenta un enfoque panorámico de estudios epidemiológicos, clínicos y experimentales referentes a Loxosceles laeta y loxoscelismo efectuados en 1955-1988 en Santiago, Chile. Se estudiaron 216 casos de loxoscelismo. Los hechos más relevantes fueron: 52,8% correspondió a mujeres; edad entre 7 meses y 78 años; 84,3% fué loxoscelismo cutáneo (LO y 15,7% loxoscelismo cutáneo-visceral (LCV; 73,6% sucedió en época calurosa; en 86,6% el accidente ocurrió en la vivienda, especialmente en dormitorios, mientras la persona dormía o se vestía. La araña fué vista en 60,2% de los casos e identificada en laboratorio como L. laeta en 17,7% (10,6% de los 216 casos. Los sitios más frecuen temente afectados fueron las extremidades con 67,6%, lancetazo urente fué el síntoma inicial más frecuente. Dolor, edema y placa livedoide, la cual posteriormente se transformaría en escara necrótica, fueron las manifestaciones locales predominantes. En LCV hematuria y hemoglobinuria fueron constantes, ictericia, fiebre y compromiso de conciencia se presentaron en la mayoría de los casos. Tratamiento: LC con antihistamínicos o corticoides inyectables, LCV con corti-coides inyectables. La condición de los pacientes en el último control fué: curación completa en 75,5%, curación con secuela cicatrizal en 8,3%, muerte en 3,7% (todos con LCV y abandono en 12,5%. Adicionalmente, se ha efectuado una serie de estudios experimentales, tanto in vivo como in vitro para esclarecer aspectos básicos sobre el veneno de L. laeta y el tratamiento del loxoscelismo.A panoramic sight of epidemiological, clinical and experimental studies, referring to Loxosceles laeta and loxoscelism, carried out in 1955-1988, in Santiago, Chile is presented. Two-hundred and sixteen cases of loxosce lism were studied. The most relevant features were: 84.3% corresponded to cutaneous loxosce lism (CD and 15.7% to viscerocutaneous loxos celism (VCD; 73.6% ocurred in hot season; in 86

  19. Fisiopatología del shock: Nuevas perspectivas Pathophysiology of shock: New perspectives

    Directory of Open Access Journals (Sweden)

    Miguel A. Jorge

    2011-10-01

    Full Text Available La actividad metabólica puede modificarse mediante la regulación de la población mitocondrial en distintas enfermedades críticas. A través de observaciones y ensayos clínicos examinamos esta adaptación metabólica en el shock cardiogénico, hemorrágico y séptico. La caída de la disponibilidad de O2 (DO2 llevaría a una reducción de la población mitocondrial y consecuentemente a una disminución del consumo de O2 (VO2. Esta secuencia permite atenuar y aun evitar la adquisición de una deuda de O2, considerada hasta hoy base fundamental de la fisiopatología del shock. El costo de esta adaptación mitocondrial es menor energía disponible y el déficit energético resultante ha sido relacionado con la falla orgánica múltiple (FOM, importante complicación de diversos procesos inflamatorios agudos y estados de shock. La FOM es mejor tolerada que el metabolismo anaeróbico y es potencialmente reversible si se revierten las causas desencadenantes y se reestablece el nivel energético por medio de la biogénesis mitocondrial.El desacople de la fosforilación oxidativa mitocondrial ocurre tanto en diversos modelos experimentales de shock como así también en el shock séptico en el hombre. Esta alteración mitocondrial puede ser detectada por un aumento desmesurado del VO2 en respuesta al incremento terapéutico de la DO2. Este aumento de la actividad metabólica puede ser equívocamente interpretado como la fase de repago de una deuda de O2.Metabolic activity can be down-regulated throughout the reduction of mitochondrial population. Lowering O2 demand in cardiogenic, hemorrhagic and septic shock is here examined through clinical observations and trials. A decrease in the availability of O2 will be followed by reductions in mitochondrial population and, therefore, in a decrease in O2 demand. This response may lessen or prevent the acquisition of an O2 debt; until now, cornerstone in the pathophysiology of shock. The cost of this

  20. Susceptibilidad a desinfectantes de Trichomonas vaginalis y Escherichia coli presentes en fómites experimentales

    OpenAIRE

    Fernando Anaya Velázquez; Valeria Leyva Vera; Felipe Padilla Vaca; Itzel Páramo Pérez; Ángeles Rangel Serrano

    2014-01-01

    Las enfermedades infecciosas provocadas por microorganismos patógenos se pueden transmitir directa o indirectamente. El protozoario Trichomonas vaginalis y la bacteria Escherichia coli son patógenos para el ser humano que pueden ser trans - mitidos por fómites. Existe una gama de productos para desinfectar, pero no existe información sobre el efecto completo de su eficacia en forma comparativa sobre bacterias o tricomonas en interacción con diferentes tipos de materiales. En este traba...

  1. Análisis de Sistemas Experimentales de Integración Peces-Pollos.

    Directory of Open Access Journals (Sweden)

    Roberto Trejo Albarrán

    2012-02-01

    Full Text Available In this work the objective was to evaluate four treatments using dung of different kinds from experimental cultures, estimating their efficiency in relation to pisciculture production and the characteristics of each pond. The work was carried out in the Laboratorio de Hidrobiología of the Universidad Autónoma del Estado de Morelos (UAEM in Cuernavaca, Morelos, Mexico, in fiberglass ponds with albinotic Oreochromis niloticus. Analysis was made of plankton, as well as bacteriological, dietectic and piscicultural growth and the physical chemistry of water. Fresh chicken excrement showed variations in the amount of nutriments. Abundance of phytoplankton was from 17,008 to 70,080 org/ml. The most abundant was Closterium sp. In zooplankton, total abundance was from 302 to 1,706 org/ml. The dominant zooplankton was Moina sp. with a yield from 22 to 117 g/m2/ 6 months. Considering these findings, it was observed that the digested chicken dung was the most efficient of the four. Pathogenic enterobacteria were always present. En este trabajo, el objetivo fue evaluar cuatro tratamientos utilizando estiércoles de diferentes tipos en cultivos experimentales, estimando su eficiencia en relación a la producción piscícola y las características de cada estanque. Se llevó a cabo en el Laboratorio de Hidrobiología de la UAEM en Cuernavaca, Morelos, México; en estanques de fibra de vidrio, con Oreochromis niloticus albina. Se realizaron análisis del plancton, bacteriológicos, bromatológicos, crecimiento piscícola y fisicoquímicos del agua. Las excretas frescas de pollo presentaron variaciones en la cantidad de nutrimentos. Las abundancias de fitoplancton fueron de 17,008 a 70,080 org/ml. Los más abundantes fueron Closterium sp. En el zooplancton, las abundancias totales fueron de 302 a 1,706 org/ml. El dominante fue Moina sp. El rendimiento fue de 22 a 117 g/m2/6 meses. Considerando lo anterior se observó que la gallinaza digerida fue el esti

  2. Enfermedad de Huntington: modelos experimentales y perspectivas terapéuticas

    Directory of Open Access Journals (Sweden)

    Teresa Serrano Sánchez

    2011-01-01

    Full Text Available La enfermedad de Huntington (EH es un trastorno degenerativo de origen hereditario. Hasta el momento no existe un tratamiento efectivo para la enfermedad que inexorablemente después de transcurridos 15 a 20 años, evoluciona hacia la incapacidad total o la muerte. En este trabajo se revisan las características clínicas y morfológicas de la EH y los modelos experimentales más utilizados para su estudio tomando como fuente, los artículos indexados en la base de datos Medline publicados en los últimos 20 años. Se valoran las ventajas y desventajas de estos modelos y su perspectiva para el desarrollo de ensayos clínicos. El consenso de lo reportado plantea que de los modelos tóxicos, los inducidos por neurotoxinas tales como el ácido quinolínico parecen ser los más adecuados para reproducir las características neuropatológicas, y por otro lado los modelos genéticos contribuyen con más evidencias al conocimiento del origen etiológico de la enfermedad. Numerosos tratamientos han sido aplicados en el manejo de las manifestaciones clínicas que aparecen en la EH, sin poder detener o disminuir las afectaciones que derivan de la pérdida neuronal. La sintomatología clínica ha sido posible reproducirla, al menos en parte, en animales de experimentación lo que ha permitido realizar ensayos terapéuticos. Desde el punto de vista de tratamiento, lo que más promisorio parece ser, es el trasplante de fuentes celulares y dentro de ellas las no neurales, que implican menor censura ética y mayor factibilidad de obtención para la aplicación en los enfermos. Por otro lado el desarrollo de la tecnología del ARN interferente, emerge como una herramienta terapéutica potencial para el tratamiento de la EH, así como para responder interrogantes básicas relacionadas con el desarrollo de la enfermedad.

  3. Enfermedad de Huntington: modelos experimentales y perspectivas terapéuticas

    Directory of Open Access Journals (Sweden)

    Blanco Lezcano Lisette

    2011-04-01

    Full Text Available La enfermedad de Huntington (EH es un trastorno degenerativo de origen hereditario. Hasta el momento no existe un tratamiento efectivo para la enfermedad que inexorablemente después de transcurridos 15 a 20 años, evoluciona hacia la incapacidad total o la muerte. En este trabajo se revisan las características clínicas y morfológicas de la EH y los modelos experimentales más utilizados para su estudio tomando como fuente, los artículos indexados en la base de datos Medline publicados en los últimos 20 años. Se valoran las ventajas y desventajas de estos modelos y su perspectiva para el desarrollo de ensayos clínicos. El consenso de lo reportado plantea que de los modelos tóxicos, los inducidos por neurotoxinas tales como el ácido quinolínico parecen ser los más adecuados para reproducir las características neuropatológicas, y por otro lado los modelos genéticos contribuyen con más evidencias al conocimiento del origen etiológico de la enfermedad. Numerosos tratamientos han sido aplicados en el manejo de las manifestaciones clínicas que aparecen en la EH, sin poder detener o disminuir las afectaciones que derivan de la pérdida neuronal. La sintomatología clínica ha sido posible reproducirla, al menos en parte, en animales de experimentación lo que ha permitido realizar ensayos terapéuticos. Desde el punto de vista de tratamiento, lo que más promisorio parece ser, es el trasplante de fuentes celulares y dentro de ellas las no neurales, que implican menor censura ética y mayor factibilidad de obtención para la aplicación en los enfermos. Por otro lado el desarrollo de la tecnología del ARN interferente, emerge como una herramienta terapéutica potencial para el tratamiento de la EH, así como para responder interrogantes básicas relacionadas con el desarrollo de la enfermedad.

  4. Efecto de pequeñas corrientes de aire sobre un Levitron®

    OpenAIRE

    Núñez Álvarez, Daniel

    2016-01-01

    El trabajo que a continuación se desarrolla se centra principalmente en el estudio sobre la dinámica del Levitron®. En primer lugar, en el capítulo 1 se realiza una introducción del sistema físico en estudio, su historia y las ecuaciones que gobiernan el sistema. En el capítulo 2 se pretende caracterizar el campo magnético generado por la base. En primer lugar se estudia un modelo teórico y, posteriormente, se ajusta el valor de los parámetros utilizando los valores experimentales obtenidos ...

  5. SÍNTESIS IN SITU DE NANOPARTÍCULAS DE PLATA SOBRE FIBRAS DE FIQUE

    Directory of Open Access Journals (Sweden)

    Sergio Ovalle

    2014-07-01

    Full Text Available Se realizó la síntesis de un material nanocompuesto mediante la deposiciónin situ de nanopartículas (NPs de plata sobre fibras de Fique. La influencia de parámetros experimentales, como concentración del precursor, concentración del agente reductor y tiempos de inmersión de las fibras en la solución del precursor y del agente reductor, se evaluó en términos de recubrimiento, tamaño y dispersión del nanomaterial sobre la superficie. Los nanocompositos fueron caracterizados mediante espectroscopia de reflectancia difusa UV-Vis (RD, microscopía electrónica (FESEM y difracción de rayos X (DRX. El control de los parámetros experimentales mencionados permitió obtener un material que exhibe recubrimiento uniforme y completo de NPs sobre la superficie y tamaños promedio de NPs de 40 nm. 

  6. Electrofisiologia de los receptores y vias neuronales del sistema audio-vestibular en seres humanos y en animales experimentales

    Directory of Open Access Journals (Sweden)

    José A. A. de Oliveira

    1987-01-01

    Full Text Available El estudio electrofisiológico del sistema audio-vestibular en animales y humanos es muy importante en fisiología sensorial y en laberintología. En este estudio se presentan los métodos para el regístro coclear y de los potenciales de acción nerviosa con electrodos implantados en la ventana oval en animales experimentales normales (conejillos de indias. Se muestran también los métodos de registro de respuestas del tallo cerebral en animales experimentales normales y en seres humanos. Además se discutió la importancia de estos métodos en el estudio de la ototoxidad experimental en la evaluación de niños sordos y en la localización de lesiones en el tallo cerebral. Fueron descritos el método de registro de nistagmos por medio de estimulación térmica y rotatoria en animales y humanos, y se mostraron los resultados en individuos normales. Se enfatizó la importancia de la electronistagmografía para el estudio de la ototoxidad experimental y la detección de patologías vestibulares

  7. Shock activation of catalysts

    Science.gov (United States)

    Graham, R. A.; Morosin, B.; Richards, P. M.; Stohl, F. V.; Granoff, B.

    1981-02-01

    Scientists in the Soviet Union have demonstrated that high pressure shock-wave loading can cause significant improvement in the performance of catalysts. This increased catalytic activity is apparently the result of the shock-induced defects, especially vacancies, which act to facilitate atomic migration. We have carried out shock activation experiments on a coal-derived pyrite which has been previously used as a catalyst in coal liquefaction studies. The pyrite powder was packed to a density of about 2.0 Mg/m3 in a copper capsule and explosively loaded to a pressure of about 15 GPa in the copper. The starting and shock-activated samples were analyzed by x-ray diffraction and magnetization measurements. The diffraction patterns of the shock-activated samples were dominated by broadened pyrite lines indicative of a significant increase in crystal defects. The diffraction patterns also showed the presence of pyrrhotite (Fe1-xS) in quantities of a few percent. An iron carbide found in the shocked material was apparently formed from carbon originating from either the calcite or organic impurities in the starting material. Magnetic properties of the sample were found to be substantially changed by the shock loading. The study has demonstrated that shock loading can significantly alter the crystalline order of pyrite and produce measurable quantities of pyrrhotite. The effects of shock-activated pyrite on the liquefaction of coal are being assessed by means by tubing reactor experiments.

  8. Shock Metamorphism in L Chondrites Above Shock Stage S6

    Science.gov (United States)

    Hu, J.; Sharp, T. G.; De Carli, P. S.

    2013-09-01

    We investigated several L6 chondrites shocked to between stage S6 and whole rock melting. The study presents the effects of high post-shock temperature and the annealing of high-pressure evidence in highly shocked chondrites.

  9. Our Favorite Film Shocks

    DEFF Research Database (Denmark)

    Willerslev, Rane; Suhr, Christian

    2014-01-01

    The modern medium of film has long been hailed for its capacity for producing shocks of an entertaining, thought-provoking, or even politically emancipative nature. But what is a shock, how and when does it occur, how long does it last, and are there particular techniques for producing cinematic...

  10. LOS CONOCIMIENTOS EXPERIMENTALES EN LAS PRÁCTICAS EDUCATIVAS DE LOS PARALELOS CON TIEMPO EXTENDIDO BAJO EL PROGRAMA MÁS EDUCACIÓN: UN ESTUDO DE CASO EN DUQUE DE CAXIAS/RJ

    Directory of Open Access Journals (Sweden)

    Sheila Cristina Monteiro Matos

    2012-07-01

    Full Text Available Este estudio tuvo como objetivo analizar cómo se está desarrollando el conocimiento experimental en las prácticas educativas de la Escuela Municipal Visconde de Itaboraí, en el municipio de Duque de Caxias, desde la aplicación del Programa “Más Educación/Más Escuela”. Para ello, se utilizó el método dialéctico impartido por Frigotto, teniendo como método de análisis el estudio de caso. El trabajo de campo se desarrolló a través de entrevistas, observaciones y la investigación de registros. El análisis de datos se realizó mediante análisis de contenido según Bardin. El estudio de la práctica educativa y del conocimiento experimental tuve como referencia las enseñanzas de Tardif sobre el conocimiento docente. En síntesis, podemos decir que los conocimientos experimentales en las prácticas educativas promueven la formación integral, proporcionando un mejor rendimiento académico de los estudiantes, aunque tímidamente, pues la articulación de las materias entre los turnos es un obstáculo importante para la efectividad de las prácticas educativas.

  11. La conformación del cáncer como objeto científico y problema sanitario en la Argentina: discursos, prácticas experimentales e iniciativas institucionales, 1903-1922

    Directory of Open Access Journals (Sweden)

    José D. Buschini

    2014-06-01

    Full Text Available El trabajo analiza la conformación del cáncer como problema sanitario y como objeto científico en la Argentina en las dos primeras décadas del siglo XX. Se consideran la adquisición y circulación de conocimientos foráneos sobre el tema, el contexto en el que surgieron los primeros desarrollos experimentales, las iniciativas institucionales promovidas desde la profesión médica y el modo en que se logró interesar a las autoridades estatales y a la sociedad civil para darles curso. Se estudia de manera detallada el proceso de creación del Instituto de Medicina Experimental, un centro destinado enteramente al estudio y el tratamiento del cáncer, inaugurado en el año 1922 y que clausura simbólicamente la primera etapa de conformación del cáncer como problema en el país.

  12. Reflection of curved shock waves

    Science.gov (United States)

    Mölder, S.

    2017-09-01

    Shock curvatures are related to pressure gradients, streamline curvatures and vorticity in flows with planar and axial symmetry. Explicit expressions, in an influence coefficient format, are used to relate post-shock pressure gradient, streamline curvature and vorticity to pre-shock gradients and shock curvature in steady flow. Using higher order, von Neumann-type, compatibility conditions, curved shock theory is applied to calculate the flow near singly and doubly curved shocks on curved surfaces, in regular shock reflection and in Mach reflection. Theoretical curved shock shapes are in good agreement with computational fluid dynamics calculations and experiment.

  13. Pediatric Toxic Shock Syndrome

    Directory of Open Access Journals (Sweden)

    Jennifer Yee

    2017-09-01

    Full Text Available Audience: This scenario was developed to educate emergency medicine residents on the diagnosis and management of a pediatric patient with toxic shock syndrome. The case is also appropriate for teaching of medical students and advanced practice providers, as well as a review of the principles of crisis resource management, teamwork, and communication. Introduction: Toxic shock syndrome is a low-frequency, high-acuity scenario requiring timely identification and aggressive management. If patients suffering from this condition are managed incorrectly, they may progress into multi-organ dysfunction and potentially death. Toxic shock syndrome has been associated with Streptococcus and Staphylococcus aureus (Staph. Approximately half of Staph cases are associated with menstruation, which was first described in the 1970s-1980s and was associated with the use of absorbent tampons.1 Group A Streptococcus may cause complications such as necrotizing fasciitis and gangrenous myositis.2 Pediatric patients may present critically ill from toxic shock syndrome. Providers need to perform a thorough history and physical exam to discern the source of infection. Management requires aggressive care with antibiotics and IV fluids. Objectives: By the end of this simulation session, the learner will be able to: 1 Recognize toxic shock syndrome. 2 Review the importance of a thorough physical exam. 3 Discuss management of toxic shock syndrome, including supportive care and the difference in antibiotic choices for streptococcal and staphylococcal toxic shock syndrome. 4 Appropriately disposition a patient suffering from toxic shock syndrome. 5 Communicate effectively with team members and nursing staff during a resuscitation of a critically ill patient. Method: This session was conducted using high-fidelity simulation, followed by a debriefing session and lecture on toxic shock syndrome.

  14. Shock breakout theory

    OpenAIRE

    Waxman, Eli; Katz, Boaz

    2016-01-01

    The earliest supernova (SN) emission is produced when the optical depth of the plasma lying ahead of the shock, which ejects the envelope, drops below c/v, where v is the shock velocity. This "breakout" may occur when the shock reaches the edge of the star, producing a bright X-ray/UV flash on time scales of seconds to a fraction of an hour, followed by UV/optical "cooling" emission from the expanding cooling envelope on a day time-scale. If the optical depth of circumstellar material (CSM) e...

  15. Distribución de fuerzas en medios granulares no cohesivos: Observaciones experimentales y computacionales

    Directory of Open Access Journals (Sweden)

    Watson L. Vargas

    2005-01-01

    Full Text Available La comprensión de las propiedades mecánicas de los medios granulares es importante en aplicaciones de Ingeniería civil, Ingeniería química, ciencias geofísicas al igual que en otras áreas del conocimiento. Es bien sabido que las fuerzas dentro de un medio granular se distribuyen siguiendo una red altamente no-lineal de partículas bajo esfuerzo. Las fuerzas por arriba del promedio se concentran en una red de “cadenas de esfuerzo” que soportan la gran mayoría de la carga, mientras que existen partículas dentro del lecho que se encuentran prácticamente aisladas de sus vecinas y que no soportan carga alguna. Dado que las fuerzas inter-partícula y su distribución determinan las propiedades macroscópicas de un sistema granular, dicho comportamiento tiene consecuencias muy importantes en fenómenos de transporte tales como conducción de calor, propagación de sonido y conducción eléctrica. En este trabajo se presentan resultados de una investigación tanto experimental como computacional sobre el comportamiento de la distribución de esfuerzos en un medio granular estático. Los resultados expuestos proveen conocimientos nuevos sobre la física de medios granulares y complementan observaciones previas

  16. Shock wave treatment in medicine

    Indian Academy of Sciences (India)

    Extracorporeal shock wave therapy in orthopedics and traumatology is still a young therapy method. Since the last few years the development of shock wave therapy has progressed rapidly. Shock waves have changed the treatment of urolithiasis substantially. Today shock waves are the first choice to treat kidney and ...

  17. An assessment of the impacts of recent food market shocks on food prices using price transmission analysis

    OpenAIRE

    Hassouneh, Islam

    2012-01-01

    Los mercados mundiales agroalimentarios se han visto recientemente afectados por shocks importantes tales como crisis alimentarias y el estallido del mercado de los biocombustibles. La presente tesis contribuye de forma significativa a la literatura existente sobre la transmisión de precios, analizando los impactos que estos shocks de mercado han tenido sobre los niveles de precios de los alimentos y la estabilidad de los mismos. Para ello se aplican modelos de econometría de s...

  18. [Pathophysiology of hemorragic shock].

    Science.gov (United States)

    Copotoiu, R; Cinca, E; Collange, O; Levy, F; Mertes, P-M

    2016-11-01

    This review addresses the pathophysiology of hemorrhagic shock, a condition produced by rapid and significant loss of intravascular volume, which may lead to hemodynamic instability, decreases in oxygen delivery, decreased tissue perfusion, cellular hypoxia, organ damage, and death. The initial neuroendocrine response is mainly a sympathetic activation. Haemorrhagic shock is associated altered microcirculatory permeability and visceral injury. It is also responsible for a complex inflammatory response associated with hemostasis alteration. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  19. Circulatory shock in horses

    OpenAIRE

    José Monteira da Silva Filho; Maristela Silveira Palhares; Cíntia Ferreira; Ubiratan Pereira de Melo

    2010-01-01

    Circulatory shock can be defined as an acute circulatory failure with an inadequate tissue delivery of oxygen and nutritive substrates to the tissues, resulting in generalised cellular hypoxia. Shock can be classified as cardiogenic, obstructive, hypovolaemic, or distributive. The pathophysiologic consequences of inadequate tissue perfusion are directly related to cell ischemia, inadequate O2 delivery, and the production of proinflammatory mediators. If abnormalities of tissue perfusion are a...

  20. Efecto de la adición de nitratos a la dieta sobre la mortalidad de pollos broiler

    OpenAIRE

    C. Orozco Sanabria; Rojas Barreto, M.

    2012-01-01

    Objetivos: este estudio investigó el efecto de la adición de nitratos en la dieta sobre la mortalidad de pollos broiler. Materiales y métodos: se utilizaron 100 pollos de estirpe Ross de un día de nacidos, divididos aleatoriamente en cuatro grupos. Se cuantificó el contenido de nitratos en el pienso comercial y el agua de bebida por una técnica colorimétrica basada en la nitridación del ácido sulfúrico. Los sujetos experimentales de los cuatro grupos recibieron pienso y agua ad...

  1. EFECTO DE LA ADICIÓN DE NITRATOS A LA DIETA SOBRE LA MORTALID AD DE POLLOS BROILER

    OpenAIRE

    C. Orozco Sanabria; Rojas Barreto, M.

    2010-01-01

    Objetivos: este estudio investigó el efecto de la adición de nitratos en la dieta sobre la mortalidad de pollos broiler. Materiales y métodos: se utilizaron 100 pollos de estirpe Ross de un día de nacidos, divididos aleatoriamente en cuatro grupos. Se cuantificó el contenido de nitratos en el pienso comercial y el agua de bebida por una técnica colorimétrica basada en la nitridación del ácido sulfúrico. Los sujetos experimentales de los cuatro grupos recibieron pienso y agua ad libitum en las...

  2. Estudio experimental sobre correlaciones en suelos granulares finos (arenas) compactados, usando equipos de penetración

    OpenAIRE

    Atala Abad, César Augusto

    2011-01-01

    El presente trabajo de tesis es el resultado de un estudio experimental sobre las correlaciones de los diferentes equipos de penetración, en un suelo arenoso igualmente compactado, a fin de establecer ecuaciones de correlación entre ellas. Los ensayos experimentales se llevaron a cabo en un pozo de 2.00 metros de diámetro y 10.00 metros de profundidad, excavado en una zona de jardín situado frente al Laboratorio de Mecánica de Suelos de la Facultad de Ingeniería Civil de la Universidad Na...

  3. Variabilidad de las proporciones molares en poblaciones humanas: un abordaje empleando modelos del desarrollo y experimentales / Variability of molar proportions in human populations: insights from developmental models and experiments in mice

    Directory of Open Access Journals (Sweden)

    Lucas A. D´Addona

    2016-03-01

    Full Text Available Los datos sobre la variación dental interpoblacional y sobre los mecanismos que regulan el desarrollo dental aportados por estudios experimentales aún no han sido integrados en el contexto de investigaciones antropobiológicas. En este sentido, el presente trabajo se propone: a evaluar la consistencia entre la variación de las proporciones molares en poblaciones humanas que exhiben gran variación en el tamaño dental con las predicciones derivadas de un modelo de desarrollo dental de cascada inhibitoria, y b analizar el efecto de los factores sistémicos que controlan el crecimiento del organismo sobre las proporciones de los molares inferiores empleando cepas de Mus musculus. Se calcularon las áreas de los molares inferiores mediante los diámetros bucolingual y mesiodistal. La variación interpoblacional en las proporciones M2/M1 y M3/M1 fue concordante con las expectativas derivadas del modelo y la mayoría de los grupos exhibieron una tendencia a la reducción del tamaño en sentido antero-posterior. Asimismo, se observó una asociación significativa y positiva entre el área molar total y las proporciones molares. En los modelos experimentales la alteración del crecimiento por factores sistémicos (subnutrición proteica y reducción de la hormona de crecimiento resultó en la disminución del área molar total y cambios en las proporciones molares. Estos últimos, consistentes con el incremento del efecto inhibitorio en sentido antero-posterior. En conjunto, los resultados sugieren que la modificación de los factores sistémicos que regulan el área molar total podría conducir a cambios en la proporción de activadores-inhibidores y contribuir a la diferenciación interpoblacional en las proporciones molares. Palabras clave: Modelo de cascada inhibitoria; tamaño dental; aproximación experimental y comparativa Data on dental variation among human populations and the mechanisms regulating tooth development elucidated by

  4. Efectos de las instrucciones audiovisuales no explícitas sobre el comportamiento alimentario

    Directory of Open Access Journals (Sweden)

    Hortencia Alicia Barrera Pelayo

    2010-01-01

    Full Text Available Este estudio evaluó los efectos de las instrucciones no explícitas sobre la conducta alimentaria. Participaron cinco jóvenes entre los 19 y 24 años, a quienes se les observó durante dos fases experimentales a dos tipos de alimento nutricional (fruta y agua y no nutricional (papas fritas y refresco. Los participantes fueron f lmados en dos programas de video. En la primera fase se grabaron videos musicales y en la segunda, un documental sobre hábitos alimentarios saludables. Los resultados mostraron que las instrucciones no explícitas modificaron la conducta alimentaria. Sin embargo, es necesario evaluar si estas modificaciones persisten a largo plazo.

  5. Algunas aportaciones sobre la enseñanza y divulgación de la ciencia

    OpenAIRE

    Calvo, María Araceli; Castro-Acuña, Carlos Mauricio; Hernández, José María; Kelter, Paul; Martín Sánchez, Manuela; Martín Sánchez, María Teresa; Prolongo Sarria, Maria Luisa; Pinto Cañón, Gabriel

    2013-01-01

    Se aportan una serie de ideas y consideraciones sobre temas variados relacionados tanto con el ámbito de la enseñanza como con el de la divulgación de las ciencias experimentales y, de forma específica, la química y la física. Las ideas expuestas en este artículo son, en buena medida, fruto del trabajo asociado a la preparación y celebración de una Jornada en Madrid, en 2012, sobre "Enseñanza y divulgación de la química y la física". Los trabajos presentados en dicho evento se recopilaron en ...

  6. Impacto inelástico de una partícula sobre una superficie

    Directory of Open Access Journals (Sweden)

    W. L. Vargas

    2006-01-01

    Full Text Available En este estudio se presentan fundamentos básicos sobre la evaluación experimental del coeficiente de restitución aplicando tres métodos de estimación diferentes. Experimentalmente se ha estudiado la colisión normal de una esfera sin rotación sobre una pared plana lisa, explorando un rango significativo de materiales, velocidades de impacto y tamaños de partícula. Los resultados muestran la consistencia de las tres metodologías, las cuales rinden información complementaria. Se ha aplicado un modelo simplificado que reproduce de manera satisfactoria las observaciones experimentales.

  7. Shock Detector for SURF model

    Energy Technology Data Exchange (ETDEWEB)

    Menikoff, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-01-11

    SURF and its extension SURFplus are reactive burn models aimed at shock initiation and propagation of detonation waves in high explosives. A distinctive feature of these models is that the burn rate depends on the lead shock pressure. A key part of the models is an algorithm to detect the lead shock. Typically, shock capturing hydro algorithms have small oscillations behind a shock. Here we investigate how well the shock detection algorithm works for a nearly steady propagating detonation wave in one-dimension using the Eulerian xRage code.

  8. Aspectos Morfológicos – Experimentales de la Tolerancia Biológica de Agentes Hemostáticos Reabsorbibles Implantados en Tejido Óseo.

    OpenAIRE

    Morote y Jurado, José Luis

    2017-01-01

    1.- Se realiza un estudio comparativo de implantaciones en orden a localización, sustancia empleada y tiempo de evolución, utilizando como agentes hemostáticos, cera y esponja de gelatina-cera, realizando un total de 336 implantaciones experimentales en las extremidades del perro, a nivel de las distintas porciones del tejido óseo (cortical, esponjosa, articular), así como en el espesor de las masas musculares, para realizar su posterior examen macrosc&oac...

  9. Desarrollo de estrategias terapéuticas basadas en esteroides neuroactivos y neuroesteroides para el tratamiento de neuropatologías experimentales

    OpenAIRE

    de Nicola, Alejandro Federico; Beauquis, Juan; Coronel, Maria Florencia; Garay, Laura Ines; Gonzalez Deniselle, Maria Claudia; Gonzalez, Susana Laura; Labombarda, Maria Florencia; Pietranera, Luciana; Saravia, Flavia Eugenia; Meyer, Maria; Gargiulo Monachelli, Gisella Mariana; Brocca, María Elvira; Overveld, Lydia Van; Lima, Analia Ethel; Roig, Paulina

    2017-01-01

    Los esteroides activos en el sistema nervioso ("neuroactivos") ejercen actividades neuroprotectoras o neurotóxicas, dependiendo de su estructura química, de las concentraciones circulantes o tisulares, del tipo de receptores intervinientes y de los mecanismos de señalización intracelular empleados. Estas propiedades han sido estudiadas en modelos animales de neuropatologías humanas. Bajo condiciones experimentales que remedan el traumatismo de la médula espinal, dolor neuropático, esclerosis ...

  10. Physics of Collisionless Shocks Space Plasma Shock Waves

    CERN Document Server

    Balogh, André

    2013-01-01

    The present book provides a contemporary systematic treatment of shock waves in high-temperature collisionless plasmas as are encountered in near Earth space and in Astrophysics. It consists of two parts. Part I develops the complete theory of shocks in dilute hot plasmas under the assumption of absence of collisions among the charged particles when the interaction is mediated solely by the self-consistent electromagnetic fields. Such shocks are naturally magnetised implying that the magnetic field plays an important role in their evolution and dynamics. This part treats both subcritical shocks, which dissipate flow energy by generating anomalous resistance or viscosity, and supercritical shocks. The main emphasis is, however, on super-critical shocks where the anomalous dissipation is insufficient to retard the upstream flow. These shocks, depending on the direction of the upstream magnetic field, are distinguished as quasi-perpendicular and quasi-parallel shocks which exhibit different behaviours, reflecti...

  11. Acción de los iones SO4-2, Cl- y Na+, contenidos en el agua de amasado, sobre las resistencias mecánicas de los morteros normales de ensayo

    Directory of Open Access Journals (Sweden)

    García de Paredes y Gaibrois, Pablo

    1979-06-01

    Full Text Available En los resultados experimentales expuestos bajo este título, en el n.º 173 de esta Revista, mencionábamos la escasez de experiencias sobre las acciones químicas que los iones contenidos en el agua, empleada para amasar las probetas, pueden desarrollar en las armaduras. Agradecemos mucho a la Sra. D. Carmen Andrade, Dra. en Química y colaboradora del C.S.I.C, en el Departamento de Química del I.E.T.C.C., los siguientes informes obtenidos en su amplia y valiosa experimentación sobre la durabilidad de las armaduras.

  12. Efecto de los metales sobre microcrustáceos de agua dulce. Avances metodológicos y potencialidad de cladóceros y copépodos como organismos test

    OpenAIRE

    María Florencia Gutierrez; Ana María Gagneten

    2012-01-01

    El incremento de los metales en los cuerpos de agua dulce a causa de las actividades antropogénicas genera importantes alteraciones sobre la biota. Esta revisión analiza los efectos adversos de varios metales de relevancia ecotoxicológica sobre los microcrustáceos zooplanctónicos (cladóceros y copépodos), los avances experimentales en esta línea y las ventajas de cada grupo como organismos test. En general, la necesidad de obtener indicadores más sensibles y representativos que los tradiciona...

  13. Culture shock and travelers.

    Science.gov (United States)

    Stewart, L; Leggat, P A

    1998-06-01

    As travel has become easier and more affordable, the number of people traveling has risen sharply. People travel for many and varied reasons, from the business person on an overseas assignment to backpackers seeking new and exotic destinations. Others may take up residence in different regions, states or countries for family, business or political reasons. Other people are fleeing religious or political persecution. Wherever they go and for whatever reason they go, people take their culture with them. Culture, like language, is acquired innately in early childhood and is then reinforced through formal and complex informal social education into adulthood. Culture provides a framework for interpersonal and social interactions. Therefore, the contact with a new culture is often not the exciting or pleasurable experience anticipated. When immersed in a different culture, people no longer know how to act when faced with disparate value systems. Contact with the unfamiliar culture can lead to anxiety, stress, mental illness and, in extreme cases, physical illness and suicide. "Culture shock" is a term coined by the anthropologist Oberg. It is the shock of the new. It implies that the experience of the new culture is an unpleasant surprise or shock, partly because it is unexpected and partly because it can lead to a negative evaluation of one's own culture. It is also known as cross-cultural adjustment, being that period of anxiety and confusion experienced when entering a new culture. It affects people intellectually, emotionally, behaviorally and physically and is characterized by symptoms of psychological distress. Culture shock affects both adults and children. In travelers or workers who have prolonged sojourns in foreign countries, culture shock may occur not only as they enter the new culture, but also may occur on their return to their original culture. Children may also experience readjustment problems after returning from leading sheltered lives in expatriate

  14. Pragmática y metapragmática en lengua materna. ¿Qué nos dicen los datos experimentales sobre su adquisición?

    OpenAIRE

    Horno Chéliz, M. Carmen; Ibáñez Buisan, Lidia

    2015-01-01

    Este artículo trata de responder a dos preguntas, por medio de dos experimentos tomados de Noveck (2001): (i) ¿es la adquisición de la competencia pragmática posterior a la de la competencia semántica?. Los resultados de nuestro estudio indican que la adquisición de la información semántica y pragmática es simultánea. La adquisición de la capacidad metapragmática es, sin embargo, posterior y eso es lo que puede justificar que en ocasiones parezca que ...

  15. Pragmática y metapragmática en lengua materna. ¿Qué nos dicen los datos experimentales sobre su adquisición?

    OpenAIRE

    María del Carmen Horno Chéliz; Lidia Ibáñez Buisán

    2015-01-01

    Este artículo presenta dos experimentos tomados de Noveck (2001): el primero pretende investigar si la adquisición de la competencia pragmática es posterior a la de la competencia semántica. Los resultados indican que la adquisición de la información semántica y pragmática es simultánea. La adquisición de la capacidad metapragmática es, sin embargo, posterior y eso es lo que puede justificar que en ocasiones parezca que la capacidad pragmática lo es. El segundo profundiza en la adquisición de...

  16. Pragmática y metapragmática en lengua materna. ¿Qué nos dicen los datos experimentales sobre su adquisición?

    Directory of Open Access Journals (Sweden)

    María del Carmen Horno Chéliz

    2015-11-01

    Full Text Available Este artículo presenta dos experimentos tomados de Noveck (2001: el primero pretende investigar si la adquisición de la competencia pragmática es posterior a la de la competencia semántica. Los resultados indican que la adquisición de la información semántica y pragmática es simultánea. La adquisición de la capacidad metapragmática es, sin embargo, posterior y eso es lo que puede justificar que en ocasiones parezca que la capacidad pragmática lo es. El segundo profundiza en la adquisición de la capacidad metapragmática. A partir de otro experimento tomado del mismo trabajo de Noveck, se llega a la conclusión de que la adquisición de esta competencia es gradual.

  17. Control por Modos Deslizantes y Planitud Diferencial de un Convertidor de CD/CD Boost: Resultados Experimentales

    Directory of Open Access Journals (Sweden)

    R. Silva-Ortigoza

    2008-10-01

    Full Text Available Resumen: En este trabajo se presenta el control del convertidor de potencia de CD a CD Boost. En este sistema existen dos problemas de control, a saber; la regulación alrededor de un punto de equilibrio y la de seguimiento de trayectoria del voltaje de salida. Nosotros enfocamos nuestra atención al segundo problema de control. Debido a las propiedades de fase que satisface este convertidor, para realizar la tarea de seguimiento de trayectoria se diseña un controlador indirecto basado en modos deslizantes en combinación con planitud diferencial, el cual permite el seguimiento de trayectoria de la variable de fase no mínima (voltaje basado en el seguimiento de trayectoria de la variable de fase mínima (corriente. La síntesis de este controlador se realiza con la ayuda de una tarjeta de adquisición de datos National Instruments™ PCI-6025E junto con el software de aplicación MATLAB®-Simulink®. Se aplica este controlador al prototipo del convertidor Boost desarrollado y se obtienen resultados experimentales satisfactorios. Palabras clave: Control Indirecto, Convertidor de CD/CD Boost, Modos Deslizantes, Planitud Diferencial, Seguimiento de Trayectoria

  18. La interacción dialógica y el proceso de enseñanza en ciencias experimentales

    Directory of Open Access Journals (Sweden)

    Ana Lía Longhi

    2012-10-01

    Full Text Available Esta línea de investigación se origina en 1995 desde de una Tesis de Doctorado y continúa en sucesivos proyectos hasta la actualidad. La problemática educativa, común a todos ellos, es el estudio de las interacciones comunicativas en el aula, particularmente en clases de ciencias experimentales. Si bien el discurso que se conforma en el aula ha sido y es objeto de estudio de diversas disciplinas como Sociología, Lingüística, Pedagogía y Teoría de la Comunicación, muy recientemente comienza a buscar su lugar en el marco teórico de la Didáctica de la Ciencias. Establecer una comunicación que permita la emergencia de un contenido académico, que respete su epistemología y que permita un proceso constructivo en el alumno es un desafío para el docente. Desafío que compromete tanto su capacitación disciplinar y didáctica como dialógica. Analizar esta última nos permite generar elementos para un marco teórico, útiles en la formación docente, como criterios para el análisis de tal capacidad.

  19. Gastrointestinal perfusion in septic shock.

    NARCIS (Netherlands)

    Haren, E.M. van; Sleight, J.W.; Pickkers, P.; Hoeven, J.G. van der

    2007-01-01

    Septic shock is characterised by vasodilation, myocardial depression and impaired microcirculatory blood flow, resulting in redistribution of regional blood flow. Animal and human studies have shown that gastrointestinal mucosal blood flow is impaired in septic shock. This is consistent with

  20. Flow behind concave shock waves

    Science.gov (United States)

    Mölder, S.

    2017-09-01

    Curved shock theory is introduced and applied to calculate the flow behind concave shock waves. For sonic conditions, three characterizing types of flow are identified, based on the orientation of the sonic line, and it is shown that, depending on the ratio of shock curvatures, a continuously curving shock can exist with Type III flow, where the sonic line intercepts the reflected characteristics from the shock, thus preventing the formation of a reflected shock. The necessary shock curvature ratio for a Type III sonic point does not exist for a hyperbolic shock so that it will revert to Mach reflection for all Mach numbers. A demonstration is provided, by CFD calculations, at Mach 1.2 and 3.

  1. INTERFERENCE OF UNIDIRECTIONAL SHOCK WAVES

    Directory of Open Access Journals (Sweden)

    P. V. Bulat

    2015-05-01

    Full Text Available Subject of study.We consider interference of unidirectional shock waves or, as they are called, catching up shock waves. The scope of work is to give a classification of the shock-wave structures that arise in this type of interaction of shock waves, and the area of their existence. Intersection of unidirectional shock waves results in arising of a shock-wave structure at the intersection point, which contains the main shock wave, tangential discontinuity and one more reflected gas-dynamic discontinuity of unknown beforehand type. The problem of determining the type of reflected discontinuity is the main problem that one has to solve in the study of catching shock waves interference. Main results.The paper presents the pictures of shock-wave structures arising at the interaction of catching up shock waves. The areas with a regular and irregular unidirectional interaction of shocks are described. Characteristic shock-wave structures are of greatest interest, where reflected gas-dynamic discontinuity degenerates into discontinuous characteristics. Such structures have a number of extreme properties. We have found the areas of existence for such shock-wave structures. There are also areas in which the steady-state solution is not available. The latter has determined revival of interest for the theoretical study of the problem, because the facts of sudden shock-wave structure destruction inside the air intake of supersonic aircrafts at high Mach numbers have been discovered. Practical significance.The theory of interference for unidirectional shock waves and design procedure are usable in the design of supersonic air intakes. It is also relevant for application possibility investigation of catching up oblique shock waves to create overcompressed detonation in perspective detonation air-jet and rocket engines.

  2. Teleconnected food supply shocks

    Science.gov (United States)

    Bren d'Amour, Christopher; Wenz, Leonie; Kalkuhl, Matthias; Steckel, Jan Christoph; Creutzig, Felix

    2016-03-01

    The 2008-2010 food crisis might have been a harbinger of fundamental climate-induced food crises with geopolitical implications. Heat-wave-induced yield losses in Russia and resulting export restrictions led to increases in market prices for wheat across the Middle East, likely contributing to the Arab Spring. With ongoing climate change, temperatures and temperature variability will rise, leading to higher uncertainty in yields for major nutritional crops. Here we investigate which countries are most vulnerable to teleconnected supply-shocks, i.e. where diets strongly rely on the import of wheat, maize, or rice, and where a large share of the population is living in poverty. We find that the Middle East is most sensitive to teleconnected supply shocks in wheat, Central America to supply shocks in maize, and Western Africa to supply shocks in rice. Weighing with poverty levels, Sub-Saharan Africa is most affected. Altogether, a simultaneous 10% reduction in exports of wheat, rice, and maize would reduce caloric intake of 55 million people living in poverty by about 5%. Export bans in major producing regions would put up to 200 million people below the poverty line at risk, 90% of which live in Sub-Saharan Africa. Our results suggest that a region-specific combination of national increases in agricultural productivity and diversification of trade partners and diets can effectively decrease future food security risks.

  3. Fascinating World of Shock Waves

    Indian Academy of Sciences (India)

    Srimath

    The dissipation of mechanical, nuclear, chemi- cal, and electrical energy in a limited space will usually result in ... the vehicle and the shock wave usually referred to as the shock layer will be a region of high .... successfully visualized a shock wave during an electric spark discharge process using stroboscopic method.

  4. Shock Waves in Gas Dynamics

    Directory of Open Access Journals (Sweden)

    Abdolrahman Razani

    2007-11-01

    Full Text Available Shock wave theory was studied in literature by many authors. This article presents a survey with references about various topics related to shock waves: Hyperbolic conservation laws, Well-posedness theory, Compactness theory, Shock and reaction-diffusion wave, The CJ and ZND theory, Existence of detonation in Majda's model, Premixed laminar flame, Multidimensional gas flows, Multidimensional Riemann problem.

  5. STEREO interplanetary shocks and foreshocks

    Energy Technology Data Exchange (ETDEWEB)

    Blanco-Cano, X. [Instituto de Geofisica, UNAM, CU, Coyoacan 04510 DF (Mexico); Kajdic, P. [IRAP-University of Toulouse, CNRS, Toulouse (France); Aguilar-Rodriguez, E. [Instituto de Geofisica, UNAM, Morelia (Mexico); Russell, C. T. [ESS and IGPP, University of California, Los Angeles, 603 Charles Young Drive, Los Angeles, CA 90095 (United States); Jian, L. K. [NASA Goddard Space Flight Center, Greenbelt, MD and University of Maryland, College Park, MD (United States); Luhmann, J. G. [SSL, University of California Berkeley (United States)

    2013-06-13

    We use STEREO data to study shocks driven by stream interactions and the waves associated with them. During the years of the extended solar minimum 2007-2010, stream interaction shocks have Mach numbers between 1.1-3.8 and {theta}{sub Bn}{approx}20-86 Degree-Sign . We find a variety of waves, including whistlers and low frequency fluctuations. Upstream whistler waves may be generated at the shock and upstream ultra low frequency (ULF) waves can be driven locally by ion instabilities. The downstream wave spectra can be formed by both, locally generated perturbations, and shock transmitted waves. We find that many quasiperpendicular shocks can be accompanied by ULF wave and ion foreshocks, which is in contrast to Earth's bow shock. Fluctuations downstream of quasi-parallel shocks tend to have larger amplitudes than waves downstream of quasi-perpendicular shocks. Proton foreshocks of shocks driven by stream interactions have extensions dr {<=}0.05 AU. This is smaller than foreshock extensions for ICME driven shocks. The difference in foreshock extensions is related to the fact that ICME driven shocks are formed closer to the Sun and therefore begin to accelerate particles very early in their existence, while stream interaction shocks form at {approx}1 AU and have been producing suprathermal particles for a shorter time.

  6. Ringwoodite in shocked chondrites

    Science.gov (United States)

    Lingemann, C. M.; Stoffler, D.

    1994-07-01

    Since the discovery of ringwoodite in the meteorite Tenham, further studies confirmed that this mineral occurs preferentially in melt veins and melt pockets of highly shocked L chondrules. Except for some special Transmission Electron Microscopy (TEM) studies a comprehensive study of this high-pressure phase of olivine in the general scope of shock metamorphism of chondrites is missing. Eighteen ringwoodite-bearing L6(S6) chondrites were studied, some of them in more detail: L6(S6)-Catherwood, L6(S6)-Coorara, L6(S6)-Johnson City, L6(S6)-Pampa del Infierno, L6(S6)-Tenham, and L5-6(S6)-Acfer 040. They were analyzed by the optical microscope, Scanning Electron Microscopy (SEM), microprobe, and TEM. Ringwoodite is formed in chondrites at locations where localized melting occurs by shock waves exceeding 50 GPa. The localized shock-pressure and temperature concentrations are obviously favorable for the kinetics of the olivine-spinel transition. Ringwoodite crystallizes most probably not during the short peak pressure pulse but rather during the more extended phase of pressure release, where the temperature is still extremely high, presumably near the solidus of chondrites. The observed chemical variation of individual ringwoodite grains and the indication that wadsleyite coexists with ringwoodite, could be explained as follows. On release from a high-pressure-shock state, olivine transforms to an assemblage of the Beta phase (wadsleyite) and the gamma phase (ringwoodite) in the pressure range between about 20 and 13 GPa. In the two-phase region, where the Beta and gamma phases coexist under equilibrium conditions, the two phases would have compositions in the range Fa(13-25) and Fa(25-31) respectively if the primary olivine composition is 24-25 mol% Fa. This range is very near to the observed chemical variation within polycrystalline ringwoodite grains Fa(19-31).

  7. Shock Dynamics in Stellar Outbursts. I. Shock Formation

    Energy Technology Data Exchange (ETDEWEB)

    Ro, Stephen; Matzner, Christopher D., E-mail: ro@astro.utoronto.ca [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada)

    2017-05-20

    Wave-driven outflows and non-disruptive explosions have been implicated in pre-supernova outbursts, supernova impostors, luminous blue variable eruptions, and some narrow-line and superluminous supernovae. To model these events, we investigate the dynamics of stars set in motion by strong acoustic pulses and wave trains, focusing on nonlinear wave propagation, shock formation, and an early phase of the development of a weak shock. We identify the shock formation radius, showing that a heuristic estimate based on crossing characteristics matches an exact expansion around the wave front and verifying both with numerical experiments. Our general analytical condition for shock formation applies to one-dimensional motions within any static environment, including both eruptions and implosions. We also consider the early phase of shock energy dissipation. We find that waves of super-Eddington acoustic luminosity always create shocks, rather than damping by radiative diffusion. Therefore, shock formation is integral to super-Eddington outbursts.

  8. Shock detachment from curved wedges

    Science.gov (United States)

    Mölder, S.

    2017-09-01

    Curved shock theory is used to show that the flow behind attached shocks on doubly curved wedges can have either positive or negative post-shock pressure gradients depending on the freestream Mach number, the wedge angle and the two wedge curvatures. Given enough wedge length, the flow near the leading edge can choke to force the shock to detach from the wedge. This local choking can preempt both the maximum deflection and the sonic criteria for shock detachment. Analytical predictions for detachment by local choking are supported by CFD results.

  9. Bubble Dynamics and Shock Waves

    CERN Document Server

    2013-01-01

    This volume of the Shock Wave Science and Technology Reference Library is concerned with the interplay between bubble dynamics and shock waves. It is divided into four parts containing twelve chapters written by eminent scientists. Topics discussed include shock wave emission by laser generated bubbles (W Lauterborn, A Vogel), pulsating bubbles near boundaries (DM Leppinen, QX Wang, JR Blake), interaction of shock waves with bubble clouds (CD Ohl, SW Ohl), shock propagation in polydispersed bubbly liquids by model equations (K Ando, T Colonius, CE Brennen. T Yano, T Kanagawa,  M Watanabe, S Fujikawa) and by DNS (G Tryggvason, S Dabiri), shocks in cavitating flows (NA Adams, SJ Schmidt, CF Delale, GH Schnerr, S Pasinlioglu) together with applications involving encapsulated bubble dynamics in imaging (AA Doinikov, A Novell, JM Escoffre, A Bouakaz),  shock wave lithotripsy (P Zhong), sterilization of ships’ ballast water (A Abe, H Mimura) and bubbly flow model of volcano eruptions ((VK Kedrinskii, K Takayama...

  10. Modelisation numerique et validation experimentale d'un systeme de protection contre le givre par elements piezoelectriques

    Science.gov (United States)

    Harvey, Derek

    Le degivrage au moyen d'actuateurs piezoelectriques est considere comme une avenue prometteuse pour le developpement de systemes a faible consommation d'energie applicables aux helicopteres legers. Ce type de systeme excite des frequences de resonances d'une structure pour produire des deformations suffisantes pour rompre l'adherence de la glace. Par contre, la conception de tel systeme demeure generalement mal comprise. Ce projet de maitrise etudie l'utilisation de methodes numeriques pour assister la conception des systemes de protection contre le givre a base d'elements piezoelectriques. La methodologie retenue pour ce projet a ete de modeliser differentes structures simples et de simuler l'excitation harmonique des frequences de resonance au moyen d'actuateurs piezoelectriques. Le calcul des frequences de resonances ainsi que la simulation de leur excitation a ensuite ete validee a l'aide de montages experimentaux. La procedure a ete realisee pour une poutre en porte-a-faux et pour une plaque plane a l'aide du logiciel de calcul par elements finis, Abaqus. De plus, le modele de la plaque plane a ete utilise afin de realiser une etude parametrique portant sur le positionnement des actuateurs, l'effet de la rigidite ainsi que de l'epaisseur de la plaque. Finalement, la plaque plane a ete degivree en chambre climatique. Des cas de degivrage ont ete simules numeriquement afin d'etudier la possibilite d'utiliser un critere base sur la deformation pour predire le succes du systeme. La validation experimentale a confirme la capacite du logiciel a calculer precisement a la fois les frequences et les modes de resonance d'une structure et a simuler leur excitation par des actuateurs piezoelectriques. L'etude revele que la definition de l'amortissement dans le modele numerique est essentiel pour l'obtention de resultats precis. Les resultats de l'etude parametrique ont demontre l'importance de minimiser l'epaisseur et la rigidite afin de reduire la valeur des frequences

  11. Electromagnetic Structure and Electron Acceleration in Shock-Shock Interaction

    Science.gov (United States)

    Nakanotani, Masaru; Matsukiyo, Shuichi; Hada, Tohru; Mazelle, Christian X.

    2017-09-01

    A shock-shock interaction is investigated by using a one-dimensional full particle-in-cell simulation. The simulation reproduces the collision of two symmetrical high Mach number quasi-perpendicular shocks. The basic structure of the shocks and ion dynamics is similar to that obtained by previous hybrid simulations. The new aspects obtained here are as follows. Electrons are already strongly accelerated before the two shocks collide through multiple reflection. The reflected electrons self-generate waves upstream between the two shocks before they collide. The waves far upstream are generated through the right-hand resonant instability with the anomalous Doppler effect. The waves generated near the shock are due to firehose instability and have much larger amplitudes than those due to the resonant instability. The high-energy electrons are efficiently scattered by the waves so that some of them gain large pitch angles. Those electrons can be easily reflected at the shock of the other side. The accelerated electrons form a power-law energy spectrum. Due to the accelerated electrons, the pressure of upstream electrons increases with time. This appears to cause the deceleration of the approaching shock speed. The accelerated electrons having sufficiently large Larmor radii are further accelerated through the similar mechanism working for ions when the two shocks are colliding.

  12. The Shock Routine

    DEFF Research Database (Denmark)

    van Hooren, Franca; Kaasch, Alexandra; Starke, Peter

    2014-01-01

    The idea that moments of crisis form opportunities for fundamental policy change is widespread in political science and public policy. It is usually associated with historical institutionalism and the notion of ‘critical junctures’. On the basis of an in-depth analysis of social policy responses...... in Australia, Belgium, the Netherlands and Sweden over the course of four global economic shocks, we ask whether the notion of critical junctures is useful in understanding the nature of change triggered by crisis. The main empirical finding is that fundamental change in the aftermath of an exogenous shock...... is the exception rather than the rule. Instead, incremental ‘crisis routines’ based on existing policy instruments are overwhelmingly used to deal with economic hardship. We discuss these findings in the light of the psychological ‘threat-rigidity’ effect and reflect on their consequences for theories...

  13. La orientación del patio del colegio: un ejemplo para la indagación sobre Geografía en Educación Primaria

    OpenAIRE

    Limiñana, Rubén; Menargues Marcilla, María Asunción; Luján Feliu-Pascual, Isabel; Rosa Cintas, Sergio; Nicolás Castellano, Carolina; Martínez Torregrosa, Joaquín

    2016-01-01

    Realizamos una propuesta didáctica para organizar el patio del colegio a partir de la obtención de datos empíricos sobre los movimientos observables del Sol desde un lugar concreto en el planeta. Si bien, los niños pueden conocer la existencia y uso de la brújula para ubicar los puntos cardinales, la idea es que ellos lleguen a construir su propia brújula a partir del movimiento del Sol, utilizando un enfoque constructivista de la enseñanza de las ciencias experimentales. Una vez dibujada est...

  14. Operational Shock Complexity Theory

    Science.gov (United States)

    2005-05-26

    too kind to state that they envisaged complexity theory. The idea of Cognitive Dissonance is accredited to Leon Festinger and is at heart that awful...on psychological elements. 3 This monograph will only touch on a couple of the areas of change and why the concept of operational shock must evolve...attack (and thus was physical in nature), which would lead to a psychological outcome, namely the loss of will to continue fighting.44 This will to

  15. Shocks Beyond the Heliopause

    Science.gov (United States)

    Kim, T. K.; Kryukov, I.; Pogorelov, N. V.

    2016-12-01

    Voyager 1 and 2 (V1 and V2) crossed the heliospheric termination shock in December 2004 and in August 2007, respectively. While V2 is still in the inner heliosheath between the termination shock and the heliopause, a tangential discontinuity separatingthe solar wind (SW) from the local interstellar medium (LISM), V1 penetrated into the LISM in 2012 and is now sampling its properties. Since the plasma instrument onboard V1 is not operational, the Plasma Wave instrument (PWS) played a decisive role in the determination of the spacecraft crossing the heliopause and entering the LISM. Using time-dependent, data-driven boundary conditions and theoretical criteria for wave generation, we investigate the effect of shock propagation through the LISM on the generation of 2-3 kHz radio emission and, by comparing simulations with the V1 PWS and magnetometer observations derive information about the LISM plasma properties in the vicinity of the heliopause. This is done with our in-house Multi-Scale Fluid-Kinetic Simulation Suite, which solves the coupled MHD equations for plasma and Euler or Boltzmann equations for neutral atoms. A flexible adaptive mesh refinement approach allows us to increase the space resolution near the heliopause and resolve the global properties of propagating shocks.The boundary conditions are specified at 1 AU using OMNI data and a special time and space interpolation procedures that allow us to generate time-dependent, 3D distributions of plasma and magnetic field quantities. In addition we explore the effect of pickup ions of the heliospheric interface and on the heliocentric distance to the heliopause.

  16. Early Treatment in Shock

    Science.gov (United States)

    2008-06-01

    Qureshi N, Morrison DC. Alanine-glutamine dipeptide inhibits expression of inflammation- related genes in hemorrhagic shock. Clinical Nutrition Week of the...American Society for Parenteral and Enteral Nutrition, Dallas. February 12-15, 2006. (Oral presentation). Clinical Nutrition week,. 2006, p145...Pontes-Arruda A, Van Way CW III. Feeding During Sepsis: What Works, What Doesn’t. Clinical Nutrition Week of American Society of Parenteral and

  17. Early Treatment in Shock

    Science.gov (United States)

    2007-06-01

    22. Vats P, Mukherjee AK, Kumria MM, et al. Changes in the activity levels of glutamine synthetase, glutaminase and glyco- gen synthetase in rats...observed seizure activity during the post-shock period, suggesting some degree of brain damage. The hypothesis of the present study is that survival...Revised 01/13/2007 Special Article occurrence of seizures in animals undergoing carotid cannulation suggests brain damage from inadequate cerebral

  18. EFECTO DEL pH EN LA ADSORCIÓN DE CADMIO, NÍQUEL Y ZINC SOBRE UNA BENTONITA

    Directory of Open Access Journals (Sweden)

    Liz Adriana Pinilla Cuesta

    2010-11-01

    Full Text Available Se estudió el efecto del pH sobre la adsorción de cadmio, niquel y zinc, en solución acuosa a 25"C, sobre una bentonita colombiana proveniente del Valle del Cauca. Los datos experimentales se analizaron con base en las isotermas de adsorción, la constante termodinámica de reparto Kdm (calculada mediante la isoterma de Langmuir, la relación de distribución Rd (obtenida del modelo Baeyens-Bradbury y una gráfica Kurbatov. La adsorción de cadmio, niquel y zinc aumenta con el pH. El orden de adsorción encontrado: Cd > Ni≅Zn coincide con el establecido por el principio HSAB.

  19. Simulación de una Torre de Enfriamiento Mecánica Comparada con Curvas Experimentales Simulation of a Mechanical Cooling Tower Compared with Experimental Curves

    OpenAIRE

    Jader D Alean; Gail A Gutiérrez; Farid Chejne; Marlon J. Bastidas

    2009-01-01

    El objetivo del trabajo es modelar y simular una torre de enfriamiento mecánica forzada a escala piloto. Las variables físicas se correlacionaron a partir de la transferencia de calor y materia y los resultados de la simulación son analizados mediante graficas que muestran la variación de la humedad, flujo de agua, calor latente, calor sensible, calor total, temperatura del agua y del aire. El coeficiente de transferencia de materia se obtuvo a partir de los datos experimentales y la solución...

  20. Modelización del sistema de almacenamietno de energía y de su regulador de un vehículo solar de fines experimentales

    OpenAIRE

    Mendoza Zaplana, Sergio

    2015-01-01

    En este proyecto, se pretende modelizar con el programa ‘Matlab-Simulink’ un sistema de acumulación y regulación para un vehículo solar de fines experimentales. Compuesto este por un motor de corriente continua de imanes permanentes de características similares a las que presenta el prototipo del vehículo Aníbal, desarrollado por el Departamento de Ingeniería Eléctrica de la Universidad Politécnica de Cartagena. Con el objetivo de modelizar un sistema de acumulación y regulación además de ave...

  1. Cómo trabajar las ciencias experimentales a través del método Doman y las inteligencias múltiples

    OpenAIRE

    Ontoria González, Laura

    2015-01-01

    El proyecto que se presenta a continuación consiste en una propuesta didáctica innovadora relacionada con las ciencias experimentales en el aula de Infantil a través del método Doman y las Inteligencias Múltiples. El empleo de estas metodologías de manera conjunta se apoya y justifica de manera teórica y práctica. La propuesta didáctica se llevó a cabo en un centro escolar en el nivel de cuatro años, concretamente con veinticinco alumnos, con resultados muy positivos.

  2. Efecto de la ración alimenticia en el crecimiento de juveniles de tilapia Oreochromis aureus (Steindachner) bajo condiciones experimentales de cultivo

    OpenAIRE

    M. García-Ulloa

    2004-01-01

    Se evaluó el crecimiento de juveniles (2.77 g de peso promedio) de la tilapia Oreochromis aureus (Steindachner), cultivados con diferentes raciones alimenticias bajo condiciones experimentales de laboratorio. Los tratamientos consistieron en el suplemento alimenticio de 6, 8 y 10% del peso de la biomasa total, los cuales fueron estudiados por triplicado en peceras de vidrio de 113 L de capacidad, ajustando una densidad inicial de 25 peces por acuario. El ensayo tuvo una duración de 35 días, y...

  3. Quasiperpendicular high Mach number Shocks

    CERN Document Server

    Sulaiman, A H; Dougherty, M K; Burgess, D; Fujimoto, M; Hospodarsky, G B

    2015-01-01

    Shock waves exist throughout the universe and are fundamental to understanding the nature of collisionless plasmas. Reformation is a process, driven by microphysics, which typically occurs at high Mach number supercritical shocks. While ongoing studies have investigated this process extensively both theoretically and via simulations, their observations remain few and far between. In this letter we present a study of very high Mach number shocks in a parameter space that has been poorly explored and we identify reformation using in situ magnetic field observations from the Cassini spacecraft at 10 AU. This has given us an insight into quasi-perpendicular shocks across two orders of magnitude in Alfven Mach number (MA) which could potentially bridge the gap between modest terrestrial shocks and more exotic astrophysical shocks. For the first time, we show evidence for cyclic reformation controlled by specular ion reflection occurring at the predicted timescale of ~0.3 {\\tau}c, where {\\tau}c is the ion gyroperio...

  4. Shock metamorphism of carbonaceous chondrites

    Science.gov (United States)

    Scott, Edward R. D.; Keil, Klaus; Stoeffler, Dieter

    1992-01-01

    Shock effects were studied in 69 carbonaceous chondrites, including CM2, CO3, CV3, ungrouped C2-C4, and CK4-6 chondrites, using optical microscopy of thin sections. It is shown that the classification scheme of Stoeffler et al. (1991) for the progressive stages of shock metamorphism in ordinary chondrites is also applicable to carbonaceous chondrites. On the basis of shock effects in olivine, the 69 carbonaceous chondrites could be assigned to four shock stage, S1 to S4. The CM2 and CO3 groups were found to be the least shocked chondrite groups, whereas the CK4-6 and CV3 were the most strongly shocked groups.

  5. Management of Refractory Vasodilatory Shock.

    Science.gov (United States)

    Jentzer, Jacob C; Vallabhajosyula, Saraschandra; Khanna, Ashish K; Chawla, Lakhmir S; Busse, Laurence W; Kashani, Kianoush B

    2018-01-09

    Refractory shock is a lethal manifestation of cardiovascular failure defined by an inadequate hemodynamic response to high doses of vasopressor medications. Approximately 7% of critically ill patients will develop refractory shock, with short-term mortality exceeding 50%. Refractory vasodilatory shock develops from uncontrolled vasodilation and vascular hyporesponsiveness to endogenous vasoconstrictors, causing failure of physiologic vasoregulatory mechanisms. Standard approaches to the initial management of shock include fluid resuscitation and initiation of norepinephrine. When these measures are inadequate to restore BP, vasopressin or epinephrine can be added. Few randomized studies exist to guide clinical management and hemodynamic stabilization in patients who do not respond to this standard approach. Adjunctive therapies, such as hydrocortisone, thiamine, and ascorbic acid, may increase BP in severe shock and should be considered when combination vasopressor therapy is needed. Novel vasopressor agents, such as synthetic human angiotensin II, can increase BP and reduce the need for high doses of catecholamine vasopressors in severe or refractory vasodilatory shock. Few effective rescue therapies exist for established refractory shock, which emphasizes the importance of aggressive intervention before refractory shock develops, including the earlier initiation of rational combination vasopressor therapy. The present review discusses the diagnosis and management of refractory shock to offer guidance for management of this important clinical problem and to provide a framework for future research. Copyright © 2018 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

  6. Shock structure in classical magnetohydrodynamics

    Science.gov (United States)

    Kennel, Charles F.

    1988-01-01

    How the structure of coplanar MHD fast and slow shocks depends upon the relative magnitudes of the dissipation coefficients contained in classical magnetohydrodynamics is examined. An asymptotic method is used in which the scale lengths for resistivity, thermal conduction, and viscosity are widely separated, and the qualitative dependence of the shock solutions upon the ordering of the scales is studied. Upper limit Mach numbers for both fast and slow shocks are defined at which resistivity and thermal conduction taken together can provide all the shock dissipation and at which viscosity is not needed.

  7. Shock metamorphism of ordinary chondrites

    Science.gov (United States)

    Stoeffler, Dieter; Keil, Klaus; Scott, Edward R. D.

    1991-01-01

    This study proposes a revised petrographic classification of progressive stages of shock metamorphism of 26 ordinary chondrites. Six stages of shock (S1 to S6) are defined on the basis of shock effects in olivine and plagioclase as recognized by thin section microscopy, and the characteristic shock effects of each shock stage are described. It is concluded that shock effects and the sequence of progressively increasing degrees of shock metamorphosis are very similar in H, L, and LL groups. Differences in the frequency distribution of shock stages are relatively minor. It is suggested that the collisional histories of the H, L, and LL parent bodies were similar. Petrologic type-3 chondrites are deficient in stages S4 and S6 and, with increasing petrologic type, the frequency of stages S4 to S6 increases. It is suggested that the more porous and volatile-rich Type-3 chondrites are subject to melting at a lower shock pressure than the nonporous chondrites of higher petrologic type. Stage S3 is the most abundant in nearly all petrologic types.

  8. Modelos experimentales para la evaluación de la acción cicatrizante de medicamentos

    Directory of Open Access Journals (Sweden)

    Raimara González Escobar

    2002-12-01

    Full Text Available Los intentos del organismo para reparar las lesiones inducidas por agresiones locales comienzan muy precozmente en el proceso de la inflamación, y finalmente concluyen con la reparación y sustitución de las células lesionadas por células sanas. El proceso de cicatrización de una herida en la piel involucra la compleja interacción de muchos tipos de células y ocurre como una cascada secuencial de procesos solapados e íntimamente relacionados. Existen varios modelos farmacológicos experimentales que permiten evaluar la acción cicatrizante de un principio activo, profundizando en los eventos específicos de la cicatrización. En este trabajo se presentarán los detalles de algunos de estos modelos, los cuales son: modelo de lesión inducida por quemadura en curieles, modelo de 6 heridas asépticas en cerdos, promoción de cicatrización por segunda intención en ratas y modelo para predecir la distribución de un medicamento aplicado tópicamente en heridas. Estos ensayos permiten el estudio de múltiples elementos histológicos, bioquímicos, celulares y clínicos, característicos del proceso de cicatrización.The attempts of the organism to repair injuries induced by local aggressions begin very early in the inflammation process and conclude finally with the reparation and substitution of those cells damaged by sound cells. The healing process of a skin wound involves the complex interaction of many types of cells and a sequence of sneaky and closely related processes take place. There are various pharmacological experimental models allowing to evaluate the healing action of an active principle and to go deep into the specific healing events. Details are given in this paper about the following models: model of injury induced by burn in guinea pigs, model of 6 aseptic wounds in pigs, promotion of healing by second intention in rats and a model to predict the distribution of a drug topically applied in wounds. These assays make possible

  9. Etude numerique et experimentale de la reponse vibro-acoustique des structures raidies a des excitations aeriennes et solidiennes

    Science.gov (United States)

    Mejdi, Abderrazak

    Les fuselages des avions sont generalement en aluminium ou en composite renforces par des raidisseurs longitudinaux (lisses) et transversaux (cadres). Les raidisseurs peuvent etre metalliques ou en composite. Durant leurs differentes phases de vol, les structures d'avions sont soumises a des excitations aeriennes (couche limite turbulente : TBL, champs diffus : DAF) sur la peau exterieure dont l'energie acoustique produite se transmet a l'interieur de la cabine. Les moteurs, montes sur la structure, produisent une excitation solidienne significative. Ce projet a pour objectifs de developper et de mettre en place des strategies de modelisations des fuselages d'avions soumises a des excitations aeriennes et solidiennes. Tous d'abord, une mise a jour des modeles existants de la TBL apparait dans le deuxieme chapitre afin de mieux les classer. Les proprietes de la reponse vibro-acoustique des structures planes finies et infinies sont analysees. Dans le troisieme chapitre, les hypotheses sur lesquelles sont bases les modeles existants concernant les structures metalliques orthogonalement raidies soumises a des excitations mecaniques, DAF et TBL sont reexamines en premier lieu. Ensuite, une modelisation fine et fiable de ces structures est developpee. Le modele est valide numeriquement a l'aide des methodes des elements finis (FEM) et de frontiere (BEM). Des tests de validations experimentales sont realises sur des panneaux d'avions fournis par des societes aeronautiques. Au quatrieme chapitre, une extension vers les structures composites renforcees par des raidisseurs aussi en composites et de formes complexes est etablie. Un modele analytique simple est egalement implemente et valide numeriquement. Au cinquieme chapitre, la modelisation des structures raidies periodiques en composites est beaucoup plus raffinee par la prise en compte des effets de couplage des deplacements planes et transversaux. L'effet de taille des structures finies periodiques est egalement pris en

  10. Programa de viviendas experimentales en Móstoles, Comunidad de Madrid. España. (Preámbulo

    Directory of Open Access Journals (Sweden)

    Abad Carrascosa, Manuel

    1990-04-01

    Full Text Available This program consists of a total of 102 houses. They are situated in one of the housing estates in the General Urbanization Plan of the Móstoles Town Council (Town on outskirts of Madrid. The development of the prototypes of three different types of housing is to be studied with the aim of studying the experimental results of each one: — Progressive housing. — Housing with passive solar energy — Housing constructed on a basis of a special system in series. The three have the common aim of achieving finanical saving, but by different means: initial investment, saving in energy expenditure, the constructive system. The group of houses is about to be delivered into the hands of its users. We regret the incompleteness of the Information due to the lack of the most important results; the derivatives of its use and development, and Information of a social, economic, cultural, etc., character.

    Esta actuación consta de un total de 102 viviendas. Se encuentran localizadas en uno de los polígonos del Plan General de Urbanismo del Ayuntamiento de Móstoles (Población del extrarradio de Madrid. Se plantea el estudio y desarrollo, por separado, de tres prototipos diferentes de vivienda con el fin de poder estudiar los resultados experimentales de cada uno: — Viviendas progresivas. — Viviendas con energía solar pasiva. — Viviendas construidas a base de un sistema especial en serie. Los tres plantean el ahorro económico como fin común, pero desde distintas bases de partida: la inversión inicial; el ahorro energético, y el sistema constructivo. El conjunto se encuentra a punto de ser entregado a sus usuarios. Lamentamos lo incompleto de la información debido a la falta de sus resultados más importantes: los derivados de su uso y desarrollo; sociales, económicos, culturales, etcétera.

  11. Proceso de gasificación de biomasa: una revisión de estudios teórico- experimentales

    Directory of Open Access Journals (Sweden)

    Juan Pérez

    2010-01-01

    Full Text Available La situación energética y medioambiental mundial hace que la generación de energía mediante sistemas basados en energías renovables tome cada vez una mayor relevancia. Estos sistemas tienen una doble ventaja ya que posibilitan la diversificación energética y reducen la dependencia del petróleo a la vez que se disminuyen las emisiones globales de CO2. La biomasa es uno de los recursos energéticos con mayor potencial tanto en países desarrollados como emergentes pero sigue sin sufrir el desarrollo esperado. La gasificación de biomasa es uno de los sistemas con gran potencial ya que permite la generación tanto de energía térmica como eléctrica, mediante tecnologías de bajo costo como los gasificadores de lecho fijo (potencias medias- bajas, o reactores de lecho fluidizado con tecnología más exigente y con mayor capacidad de generación. La transformación de la biomasa en un combustible gaseoso, aprovechable en motores de combustión interna alternativos o en turbinas de gas como combustible, exige que la biomasa atraviese varios procesos termoquímicos, compuestos por reacciones endotérmicas (secado, devolatilización y reducción y exotérmicas (oxidación de volátiles y carbón. La selección de un gasificador requiere conocer las propiedades de la biomasa, mientras que el diseño del mismo exige conocer el fenómeno termoquímico por completo. El objetivo de este trabajo es presentar una revisión actualizada de los diferentes planteamientos tanto teóricos como experimentales desarrollados para estudiar el proceso de gasificación de biomasa, tanto en lecho fijo como en lecho fluidizado, con miras a diseñar gasificadores de biomasa.

  12. Early Treatment in Shock

    Science.gov (United States)

    2010-06-17

    Shock 8 RBC membranes.(5) After cooling, 1.0 ml water and 1.0 ml hexane containing 50 mg/L 1 butylated hydroxytoulene (BHT, an antioxidant, Sigma...LIMITATION OF ABSTRACT 18. NUMBER OF PAGES 19a. NAME OF RESPONSIBLE PERSON USAMRC U a. REPORT b. ABSTRACT U U c. THIS PAGE UU 50 19b. TELEPHONE...use of DHEA , but studies in our laboratories have failed to show a useful effect (6). Studies with omega-3 fatty acids have shown promise, but are

  13. Characterization of Shocked Beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Cady, Carl M [Los Alamos National Laboratory; Adams, Chris D [Los Alamos National Laboratory; Hull, Lawrence M [Los Alamos National Laboratory; Gray III, George T [Los Alamos National Laboratory; Prime, Michael B [Los Alamos National Laboratory; Addessio, Francis L [Los Alamos National Laboratory; Wynn, Thomas A [Los Alamos National Laboratory; Brown, Eric N [Los Alamos National Laboratory

    2012-08-24

    Beryllium metal has many excellent structural properties in addition to its unique radiation characteristics, including: high elastic modulus, low Poisson's ratio, low density, and high melting point. However, it suffers from several major mechanical drawbacks: 1) high anisotropy - due to its hexagonal lattice structure and its susceptibility to crystallographic texturing; 2) susceptibility to impurity-induced fracture - due to grain boundary segregation; and 3) low intrinsic ductility at ambient temperatures thereby limiting fabricability. While large ductility results from deformation under the conditions of compression, the material can exhibit a brittle behavior under tension. Furthermore, there is a brittle to ductile transition at approximately 200 C under tensile conditions. While numerous studies have investigated the low-strain-rate constitutive response of beryllium, the combined influence of high strain rate and temperature on the mechanical behavior and microstructure of beryllium has received limited attention over the last 40 years. Prior studies have focused on tensile loading behavior, or limited conditions of dynamic strain rate and/or temperature. The beryllium used in this study was Grade S200-F (Brush Wellman, Inc., Elmore, OH) material. The work focused on high strain rate deformation and examine the validity of constitutive models in deformation rate regimes, including shock, the experiments were modeled using a Lagrangian hydrocode. Two constitutive strength (plasticity) models, the Preston-Tonks-Wallace (PTW) and Mechanical Threshold Stress (MTS) models, were calibrated using the same set of quasi-static and Hopkinson bar data taken at temperatures from 77K to 873K and strain rates from 0.001/sec to 4300/sec. In spite of being calibrated on the same data, the two models give noticeably different results when compared with the measured wave profiles. These high strain rate tests were conducted using both explosive drive and a gas gun to

  14. A Shocking Solar Nebula?

    OpenAIRE

    Liffman, Kurt

    2009-01-01

    It has been suggested that shock waves in the solar nebula formed the high temperature materials observed in meteorites and comets. It is shown that the temperatures at the inner rim of the solar nebula could have been high enough over a sufficient length of time to produce chondrules, CAIs, refractory dust grains and other high-temperature materials observed in comets and meteorites. The solar bipolar jet flow may have produced an enrichment of 16O in the solar nebula over time and the chond...

  15. A shocking experiment

    Directory of Open Access Journals (Sweden)

    Gregory S. Berns

    2007-08-01

    Full Text Available We study whether probability weighting is observed when individuals are presented with a series of choices between lotteries consisting of real non-monetary adverse outcomes, electric shocks. Our estimation of the parameters of the probability weighting function proposed by Tversky and Kahneman (1992 are similar to those obtained in previous studies of lottery choice for negative monetary payoffs and negative hypothetical payoffs. In addition, common ratio violations in choice behavior are widespread. Our results provide evidence that probability weighting is a general phenomenon, independent of the source of disutility.

  16. Impacto de los contaminantes ambientales sobre la reproducción

    Directory of Open Access Journals (Sweden)

    Anastasia Cruz

    2007-10-01

    Full Text Available Los disruptores xenoendocrinos son contaminantes ambientales que mediante diferentes mecanismos alteran la fisiología hormonal de los animales y de los seres humanos. Esta revisión se hizo con el fin de recopilar información reciente, sobre los grupos de químicos a los que se les ha demostrado este efecto, la forma como lo hacen, y las consecuencias en machos y hembras en diferentes etapas de la vida. La reflexión muestra que a pesar de la gran cantidad de estudios experimentales y epidemiológicos que se han desarrollado, aún quedan hipótesis por demostrar y muchos compuestos por evaluar.

  17. El AMMI y cluster en la selección de los mejores híbridos experimentales de maíz

    Directory of Open Access Journals (Sweden)

    Guillermo Casta\\u00F1\\u00F3n

    2000-01-01

    Full Text Available El AMMI y Cluster en la selección de los mejores híbridos experimentales de maiz. En un experimento de maíz repetido en cuatro ambientes, se aplicó el análisis de efectos principales aditivos e interacción multiplicativa (AMMI y el de taxonomía numérica o cluster, para estudiar si la estabilidad del rendimiento de grano (RG de los híbridos ensayados se asociaba con el agrupamiento de los híbridos hecho por el cluster. Las variables que tuvieron más peso en el agrupamiento fueron el RG, altura de la planta (AP,altura de mazorca ( AM y mazorca por planta (PRO, principalmente. De lo encontrado en este trabajo se puede establecer que el AMMI es efectivo en la estimación de la estabilidad de los híbridos experimentales evaluados y que junto con el cluster, pueden ser dos herramientas útiles para hacer una buena selección de material experimental con mayores posibilidades de éxito

  18. Experimental techniques; Techniques experimentales

    Energy Technology Data Exchange (ETDEWEB)

    Roussel-Chomaz, P. [GANIL CNRS/IN2P3, CEA/DSM, 14 - Caen (France)

    2007-07-01

    This lecture presents the experimental techniques, developed in the last 10 or 15 years, in order to perform a new class of experiments with exotic nuclei, where the reactions induced by these nuclei allow to get information on their structure. A brief review of the secondary beams production methods will be given, with some examples of facilities in operation or under project. The important developments performed recently on cryogenic targets will be presented. The different detection systems will be reviewed, both the beam detectors before the targets, and the many kind of detectors necessary to detect all outgoing particles after the reaction: magnetic spectrometer for the heavy fragment, detection systems for the target recoil nucleus, {gamma} detectors. Finally, several typical examples of experiments will be detailed, in order to illustrate the use of each detector either alone, or in coincidence with others. (author)

  19. 30th International Symposium on Shock Waves

    CERN Document Server

    Sadot, Oren; Igra, Ozer

    2017-01-01

    These proceedings collect the papers presented at the 30th International Symposium on Shock Waves (ISSW30), which was held in Tel-Aviv Israel from July 19 to July 24, 2015. The Symposium was organized by Ortra Ltd. The ISSW30 focused on the state of knowledge of the following areas: Nozzle Flow, Supersonic and Hypersonic Flows with Shocks, Supersonic Jets, Chemical Kinetics, Chemical Reacting Flows, Detonation, Combustion, Ignition, Shock Wave Reflection and Interaction, Shock Wave Interaction with Obstacles, Shock Wave Interaction with Porous Media, Shock Wave Interaction with Granular Media, Shock Wave Interaction with Dusty Media, Plasma, Magnetohyrdrodynamics, Re-entry to Earth Atmosphere, Shock Waves in Rarefied Gases, Shock Waves in Condensed Matter (Solids and Liquids), Shock Waves in Dense Gases, Shock Wave Focusing, Richtmyer-Meshkov Instability, Shock Boundary Layer Interaction, Multiphase Flow, Blast Waves, Facilities, Flow Visualization, and Numerical Methods. The two volumes serve as a reference ...

  20. Impacto actitudinal y canalización cognitiva de estereotipos sobre la inmigración a través de las noticias

    Directory of Open Access Journals (Sweden)

    JJ Igartua

    2013-10-01

    Full Text Available Introducción. Tomando como base la investigación sobre el efecto framing y la investigación sobre el tratamiento de la inmigración, se analizan los procesos de recepción e impacto de las noticias sobre actos delictivos. Metodología. Se realizaron dos investigaciones experimentales en donde los participantes fueron expuestos a una noticia y posteriormente cumplimentaron un cuestionario con escalas de auto-informe. Se manipularon la mención del origen nacional/geográfico de los protagonistas de la noticia y la implicación con el tema de la noticia. Resultados. Se observa que cuando la implicación con el tema es baja, la presencia de información sobre el origen de los protagonistas de la noticia ejerce un efecto indirecto a través de impactar las actitudes. En cambio, cuando la implicación es alta el efecto indirecto se explica por la activación de corrientes de pensamiento que influyen en la formación y/o refuerzo de creencias negativas sobre la inmigración. Conclusiones. Los resultados son congruentes con un modelo dual de influencia de los encuadres noticiosos. Se constata con argumentos empíricos que la recomendación de no informar sobre el origen de los protagonistas en noticias sobre actos delictivos está justificada.

  1. Shock in the emergency department

    DEFF Research Database (Denmark)

    Holler, Jon Gitz; Henriksen, Daniel Pilsgaard; Mikkelsen, Søren

    2016-01-01

    BACKGROUND: The knowledge of the frequency and associated mortality of shock in the emergency department (ED) is limited. The aim of this study was to describe the incidence, all-cause mortality and factors associated with death among patients suffering shock in the ED. METHODS: Population...

  2. EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY AS

    African Journals Online (AJOL)

    2, 2002. 87-93. EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY AS. MONOTHERAPY FOR STONES IN SOLITARY KIDNEY. K. MADBOULY, E. ELSOBKY, K.Z. SHEIR, l. ERAKY AND M. KENAWY. Urology and Nephrology Center, Mansoura University, Mansoura, Egypt. Objective To evaluate extracorporeal shock.

  3. Nonparametric Regression with Common Shocks

    Directory of Open Access Journals (Sweden)

    Eduardo A. Souza-Rodrigues

    2016-09-01

    Full Text Available This paper considers a nonparametric regression model for cross-sectional data in the presence of common shocks. Common shocks are allowed to be very general in nature; they do not need to be finite dimensional with a known (small number of factors. I investigate the properties of the Nadaraya-Watson kernel estimator and determine how general the common shocks can be while still obtaining meaningful kernel estimates. Restrictions on the common shocks are necessary because kernel estimators typically manipulate conditional densities, and conditional densities do not necessarily exist in the present case. By appealing to disintegration theory, I provide sufficient conditions for the existence of such conditional densities and show that the estimator converges in probability to the Kolmogorov conditional expectation given the sigma-field generated by the common shocks. I also establish the rate of convergence and the asymptotic distribution of the kernel estimator.

  4. Oscillating nonlinear acoustic shock waves

    DEFF Research Database (Denmark)

    Gaididei, Yuri; Rasmussen, Anders Rønne; Christiansen, Peter Leth

    2016-01-01

    We investigate oscillating shock waves in a tube using a higher order weakly nonlinear acoustic model. The model includes thermoviscous effects and is non isentropic. The oscillating shock waves are generated at one end of the tube by a sinusoidal driver. Numerical simulations show...... that at resonance a stationary state arise consisting of multiple oscillating shock waves. Off resonance driving leads to a nearly linear oscillating ground state but superimposed by bursts of a fast oscillating shock wave. Based on a travelling wave ansatz for the fluid velocity potential with an added 2'nd order...... polynomial in the space and time variables, we find analytical approximations to the observed single shock waves in an infinitely long tube. Using perturbation theory for the driven acoustic system approximative analytical solutions for the off resonant case are determined....

  5. Shock waves in polycrystalline iron.

    Science.gov (United States)

    Kadau, Kai; Germann, Timothy C; Lomdahl, Peter S; Albers, Robert C; Wark, Justin S; Higginbotham, Andrew; Holian, Brad Lee

    2007-03-30

    The propagation of shock waves through polycrystalline iron is explored by large-scale atomistic simulations. For large enough shock strengths the passage of the wave causes the body-centered-cubic phase to transform into a close-packed phase with most structure being isotropic hexagonal-close-packed (hcp) and, depending on shock strength and grain orientation, some fraction of face-centered-cubic (fcc) structure. The simulated shock Hugoniot is compared to experiments. By calculating the extended x-ray absorption fine structure (EXAFS) directly from the atomic configurations, a comparison to experimental EXAFS measurements of nanosecond-laser shocks shows that the experimental data is consistent with such a phase transformation. However, the atomistically simulated EXAFS spectra also show that an experimental distinction between the hcp or fcc phase is not possible based on the spectra alone.

  6. Shock, ¿qué hay de nuevo?

    Directory of Open Access Journals (Sweden)

    Marta Sofía López Rodríguez

    Full Text Available El shock es un síndrome común de diversas causas que se inicia por una disminución de la perfusión hística, donde la microcirculación tiene una función crítica. En estudios recientes se profundiza en la terapéutica que debe ser inmediata, pues amenaza la vida e incluye: soporte respiratorio, soporte circulatorio, monitoreo metabólico, hemodinámica y tratamiento específico. El uso de cristaloides versus coloides es controversial y depende del criterio del médico. Se evidencia la utilidad de la amrinona (ionotropo, sobre todo en pacientes en shock séptico, y como vasopresor la vasopresina. El monitoreo de la concentración plasmática del ácido láctico es necesario por su relación con la mortalidad por shock. La mortalidad del shock séptico, a pesar de múltiples investigaciones, continúa elevada. Los inhibidores de la óxido-nítrico sintasa (S metil-isiotiourea de reciente utilización, parece alentador al inhibir la isoforma inducible (iNOS y de igual forma la inmunoterapia, pero se necesitan de nuevos estudios para evaluar su eficacia clínica

  7. Shock waves & explosions

    CERN Document Server

    Sachdev, PL

    2004-01-01

    Understanding the causes and effects of explosions is important to experts in a broad range of disciplines, including the military, industrial and environmental research, aeronautic engineering, and applied mathematics. Offering an introductory review of historic research, Shock Waves and Explosions brings analytic and computational methods to a wide audience in a clear and thorough way. Beginning with an overview of the research on combustion and gas dynamics in the 1970s and 1980s, the author brings you up to date by covering modeling techniques and asymptotic and perturbative methods and ending with a chapter on computational methods.Most of the book deals with the mathematical analysis of explosions, but computational results are also included wherever they are available. Historical perspectives are provided on the advent of nonlinear science, as well as on the mathematical study of the blast wave phenomenon, both when visualized as a point explosion and when simulated as the expansion of a high-pressure ...

  8. Shock induced cavity collapse

    Science.gov (United States)

    Skidmore, Jonathan; Doyle, Hugo; Tully, Brett; Betney, Matthew; Foster, Peta; Ringrose, Tim; Ramasamy, Rohan; Parkin, James; Edwards, Tom; Hawker, Nicholas

    2016-10-01

    Results from the experimental investigation of cavity collapse driven by a strong planar shock (>6km/s) are presented. Data from high speed framing cameras, laser backlit diagnostics and time-resolved pyromety are used to validate the results of hydrodynamic front-tracking simulations. As a code validation exercise, a 2-stage light gas gun was used to accelerate a 1g Polycarbonate projectile to velocities exceeding 6km/s; impact with a PMMA target containing a gas filled void results in the formation of a strong shockwave with pressures exceeding 1Mbar. The subsequent phenomena associated with the collapse of the void and excitation of the inert gas fill are recorded and compared to simulated data. Variation of the mass density and atomic number of the gas fill is used to alter the plasma parameters furthering the extent of the code validation.

  9. Some experiments on the high-low transition of quartz; Recherches experimentales sur une transformation du quartz

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, G. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1959-12-15

    , nous avons rassemble un grand nombre de resultats numeriques relatifs aux proprietes elastiques, piezoelectriques et optiques du quartz. Certains ont ete collectes dans la litterature; d'autres ont ete obtenus par nous a l'aide de methodes experimentales que nous decrivons, de facon a pouvoir presenter un tableau complet de l'evolution de ces constantes dans un domaine de temperature entourant largement le point de transformation {alpha} - {beta} situe a 574 deg. C. De nouveaux phenomenes ont ete observes au cours de ces mesures. Dans la troisieme partie, nous montrons qu'une meme fonction de la temperature decrit l'evolution de la constante piezoelectrique et de la constante elastique qui s'annulent en phase {beta}. Une seule autre fonction suffit a decrire correctement l'evolution de toutes les autres constantes etudiees, depuis leur valeur en phase {alpha} jusqu'a leur valeur en phase {beta}. A l'aide d'hypotheses sur la nature de l'entropie de transformation, nous essayons enfin d'expliquer la forme de ces fonctions. (auteur)

  10. ENFERMEDAD DE HUNTINGTON: MODELOS EXPERIMENTALES Y PERSPECTIVAS TERAPÉUTICAS Huntington'disease: Experimentals Models and Therapeutic Perspectives

    Directory of Open Access Journals (Sweden)

    TERESA SERRANO SÁNCHEZ

    Full Text Available La enfermedad de Huntington (EH es un trastorno degenerativo de Weiss de origen hereditario. Hasta el momento no existe un tratamiento efectivo para la enfermedad que inexorablemente después de transcurridos 15 a 20 años, evoluciona hacia incapacidad total o muerte. En este trabajo se revisan las características clínicas y morfológicas de la EH y los modelos experimentales más utilizados para su estudio tomando como fuente, artículos indexados en la base de datos Medline publicados en los últimos 20 años. Se valoran las ventajas y desventajas de estos modelos y su perspectiva para el desarrollo de ensayos clínicos. El consenso de lo reportado plantea que de los modelos tóxicos, los inducidos por neurotoxinas tales como ácido quinolínico parecen ser los más adecuados para reproducir las características neuropatológicas, y por otro lado los modelos genéticos contribuyen con más evidencias al conocimiento del origen etiológico de la enfermedad. Numerosos tratamientos han sido aplicados en el manejo de las manifestaciones clínicas que aparecen en EH, sin poder detener o disminuir las afectaciones que derivan de la pérdida neuronal. La sintomatología clínica ha sido posible reproducirla, al menos en parte, en animales de experimentación lo que ha permitido realizar ensayos terapéuticos. Desde el punto de vista de tratamiento, lo que más promisorio parece ser, la terapia celular con células provenientes de diferentes fuentes y dentro de ellas las no neurales, que implican menor censura ética y mayor factibilidad de obtención para la aplicación en los enfermos. Por otro lado el desarrollo de la tecnología del ARN de interferencia, emerge como una herramienta terapéutica potencial para el tratamiento de EH, así como para responder interrogantes básicas relacionadas con el desarrollo de la enfermedad.Huntington'disease (HD is a degenerative dysfunction of hereditary origin. Up to date there is not, an effective treatment

  11. CÁNCER Y TERAPÉUTICA CON PRODUCTOS DE LA COLMENA. REVISIÓN SISTEMÁTICA DE LOS ESTUDIOS EXPERIMENTALES Cancer therapy with bee products. Systematic review of experimental studies

    Directory of Open Access Journals (Sweden)

    Andrés Jagua-Gualdrón

    2012-04-01

    Full Text Available Antecedentes. Los productos de la colmena se han utilizados desde hace más de dos milenios con fines terapéuticos. Conceptos teóricos basados en la composición de los productos hacen pensar que podrían ser de utilidad en el manejo del cáncer. Objetivo. Resumir la evidencia experimental disponible en la actualidad sobre el uso de los productos de la colmena en el manejo del cáncer. Material y métodos. Se realizó una revisión sistemática de los estudios experimentales publicados a través de las bibliotecas digitales PUBMED, LiLACS y OVID en los cuales se evaluara la utilidad del uso de los distintos productos de la colmena sobre cultivos de células tumorales o sobre modelos animales de cáncer. Se realizó un análisis cualitativo de la información y se construyeron tablas de resumen. Resultados. La búsqueda arrojó un total de 391 resultados de los cuales únicamente 55 cumplieron los criterios de inclusión. El veneno de abejas, la miel y el propóleo son los productos con un mayor número de publicaciones. La mayoría son estudios in vitro y son pocos los modelos en animales realizado. Se describen los mecanismos de acción a través de los cuales estos podrían llegar a ejercer acciones farmacológicas útiles en el manejo del cáncer. Conclusión. La aplicación de los productos de la colmena en el cáncer es un campo incipiente pero prometedor de investigación. Existe evidencia experimental que documenta la plausibilidad biológica de este uso. Es necesario realizar modelos animales que permitan describir el comportamiento de los productos y documentar su seguridad y utilidad terapéutica en el cáncer.Background. The beehive products have been used for more than two millennia with therapeutic purposes. Theoretical models based on the composition of products suggest that might be useful in cancer management. Objective. To summarize experimental evidence available to date on the use of beehive products in cancer management

  12. Efecto agudo de la actividad fisicodeportiva y la expresión corporal sobre el estado de ánimo

    Directory of Open Access Journals (Sweden)

    Rafael E. Reigal Garrido

    2013-09-01

    Full Text Available Este trabajo analiza los efectos de una sesión de actividad fisicodeportiva y otra de expresión corporal sobre el estado de ánimo en un grupo de 92 adolescentes de la ciudad de Málaga (España, con edades entre los 14 y 16 años (M=14,87; DT= 0,79. En él se sigue una metodología cuasiexperimental con un diseño de tipo pre-post con grupos no equivalentes, en el que existen dos grupos experimentales que han sido sometidos a una sesión de deportes de raqueta y a otra de aeróbic. Se ha utilizado el cuestionario Profile of Mood States (POMS - McNair, Lorr, & Droppleman, 1971 para analizar los siguientes factores: tensión-ansiedad, depresión-melancolía, angustia hostilidad-cólera, vigor-actividad, fatiga-inercia y confusión-orientación. Los resultados indican que, tras la intervención, el estado de ánimo mejora en ambos grupos experimentales, observándose un efecto significativo en aquellos grupos que practican actividad física.

  13. Hemodynamic Analysis of Pediatric Septic Shock and Cardiogenic Shock Using Transpulmonary Thermodilution

    OpenAIRE

    En-Pei Lee; Shao-Hsuan Hsia; Jainn-Jim Lin; Oi-Wa Chan; Jung Lee; Chia-Ying Lin; Han-Ping Wu

    2017-01-01

    Septic shock and cardiogenic shock are the two most common types of shock in children admitted to pediatric intensive care units (PICUs). The aim of the study was to investigate which hemodynamic variables were associated with mortality in children with shock. We retrospectively analyzed 50 children with shock (37 septic shock cases and 13 cardiogenic shock cases) in the PICU and monitored their hemodynamics using transpulmonary thermodilution from 2003 to 2016. Clinical factors were analyzed...

  14. Pediatric cardiogenic shock: Current perspectives

    Directory of Open Access Journals (Sweden)

    Subhranshu Sekhar Kar

    2015-01-01

    Full Text Available Cardiogenic shock is a pathophysiologic state where an abnormality of cardiac function is responsible for the failure of the cardiovascular system to meet the metabolic needs of the body tissues.Though it is less common than hypovolemia as the primary etiology in paediatric shock, eventually myocardial function is affected because of reduced perfusion in all forms of shock. Myocardial malfunction, in other forms of shock, is secondary to ischemia, acidosis, drugs, toxins or inflammation. Cardiogenic shock is a low output state characterized by elevated filling pressures, neurohormonal activation with the evidence of end-organ hypoperfusion. The management is challenging and consists of a combination of conventional cardio-respiratory support, vasoactive medications with correction of the anatomic cardiac defects. Treatment options like Extracorporeal membrane oxygenation and Ventricular assist devices provide a bridge to recovery, surgery or transplant. As cardiogenic shock in children carries a high risk of morbidity and mortality, emphasis should be placed on expedient management to arrest the pathophysiological cascade and avoid hypotension.This article aims to review the aetio-pathophysiological basis of pediatric cardiogenic shock, diagnostic options, recent advances in management modalities and outcome.

  15. Chondrule destruction in nebular shocks

    Energy Technology Data Exchange (ETDEWEB)

    Jacquet, Emmanuel; Thompson, Christopher, E-mail: ejacquet@mnhn.fr [Canadian Institute for Theoretical Astrophysics, University of Toronto, 60 St George Street, Toronto, ON M5S 3H8 (Canada)

    2014-12-10

    Chondrules are millimeter-sized silicate spherules ubiquitous in primitive meteorites, but whose origin remains mysterious. One of the main proposed mechanisms for producing them is melting of solids in shock waves in the gaseous protoplanetary disk. However, evidence is mounting that chondrule-forming regions were enriched in solids well above solar abundances. Given the high velocities involved in shock models, destructive collisions would be expected between differently sized grains after passage of the shock front as a result of differential drag. We investigate the probability and outcome of collisions of particles behind a one-dimensional shock using analytic methods as well as a full integration of the coupled mass, momentum, energy, and radiation equations. Destruction of protochondrules seems unavoidable for solid/gas ratios ε ≳ 0.1, and possibly even for solar abundances because of 'sandblasting' by finer dust. A flow with ε ≳ 10 requires much smaller shock velocities (∼2 versus 8 km s{sup –1}) in order to achieve chondrule-melting temperatures, and radiation trapping allows slow cooling of the shocked fragments. Initial destruction would still be extensive; although re-assembly of millimeter-sized particles would naturally occur by grain sticking afterward, the compositional heterogeneity of chondrules may be difficult to reproduce. We finally note that solids passing through small-scale bow shocks around few kilometer-sized planetesimals might experience partial melting and yet escape fragmentation.

  16. Riesgos sobre la salud de los alimentos modificados genéticamente: una revision bibliografica

    Directory of Open Access Journals (Sweden)

    Roig José L. Domingo

    2000-01-01

    Full Text Available A lo largo de 1999, se ha venido intensificando el debate sobre la seguridad de los alimentos modificados genéticamente, una importante y compleja área de investigación científica, la cual demanda unos estándares rigurosos. Diversos grupos, incluyendo asociaciones de consumidores y Organizaciones no Gubernamentales (ONGs han sugerido que todos los alimentos modificados genéticamente deberían ser sometidos a estudios a largo plazo con animales antes de su aprobación para el consumo humano. El principal objetivo de la presente revisión ha sido conocer cual es el estado actual de la cuestión en lo referente a los potenciales efectos adversos sobre la salud de los alimentos modificados genéticamente. Dos bases de datos, Medline y Toxline, así como una serie de direcciones de internet, han sido empleadas para la obtención de bibliografía. Aunque son numerosos los comentarios, noticias generales y cartas al Editor aparecidos en prestigiosas revistas, los artículos referentes a estudios experimentales sobre la seguridad de los alimentos modificados genéticamente son, sorprendentemente, muy escasos. Si se han obtenido resultados procedentes de la evaluación toxicológica de estos alimentos, no han sido publicados en revistas científicas y, por lo tanto, no han podido ser debidamente juzgados o contrastados.

  17. IMPACTO DE LA EXPRESIÓN CORPORAL SOBRE LAS EMOCIONES EN EL ÁMBITO EDUCATIVO

    Directory of Open Access Journals (Sweden)

    Barriopedro Moro María Isabel

    2010-10-01

    Full Text Available

     

    Numerosos autores desde la Expresión Corporal han puesto de manifiesto cómo esta disciplina puede contribuir al desarrollo de la dimensión emocional y social del individuo, en definitiva al desarrollo afectivo del alumno. El objetivo del presente trabajo fue evaluar el cambio sobre el Bienestar Psicológico y sobre las Habilidades Sociales producido como consecuencia de la asignatura de Expresión Corporal en alumnos universitarios mediante un estudio experimental. Los resultados sólo mostraron cambios con respecto al bienestar material en dos de los tres grupos experimentales y ningún efecto de la impartición de esta asignatura sobre el Bienestar Subjetivo y las Habilidades Sociales de los sujetos. Estos resultados son incompatibles con las afirmaciones que realizan la mayor parte de los autores de este campo.
    Palabras claves: Emociones, Expresión Corporal, Bienestar psicológico y Habilidades sociales.

  18. Avances en investigación de la discapacidad intelectual de origen genético: tratamientos experimentales en el síndrome X frágil

    Directory of Open Access Journals (Sweden)

    Yolanda de Diego Otero

    2017-06-01

    Full Text Available De Diego Otero, Y. et al. (2017: “Avances en investigación de la discapacidad intelectual de origen genético: tratamientos experimentales en el síndrome X frágil”. Revista Española de Discapacidad, 5 (I: 217-227.

  19. Cardiogenic shock caused by disulfiram.

    Science.gov (United States)

    Jerónimo, Ana; Meira, Carla; Amaro, Augusta; Campello, Glória Cabral; Granja, Cristina

    2009-03-01

    Drug intoxication with disulfiram is a rare condition that may lead to severe and potentially fatal cardiovascular manifestations such as cardiogenic shock. We report the case of a female patient with refractory shock after deliberate self-poisoning with disulfiram. Clinical, biochemical and echocardiographic assessment, as well as invasive monitoring confirmed cardiogenic shock associated with this drug. The known mechanisms of action of disulfiram are discussed, and the major collateral effects, especially cardiovascular effects, are described. We underscore the importance of suspecting this diagnosis and of adopting prompt and the most adequate therapeutic approach in this context.

  20. Hemorrhagic shock: The "physiology approach"

    Directory of Open Access Journals (Sweden)

    Fabrizio Giuseppe Bonanno

    2012-01-01

    Full Text Available A shift of approach from ′clinics trying to fit physiology′ to the one of ′physiology to clinics′, with interpretation of the clinical phenomena from their physiological bases to the tip of the clinical iceberg, and a management exclusively based on modulation of physiology, is finally surging as the safest and most efficacious philosophy in hemorrhagic shock. ATLS® classification and recommendations on hemorrhagic shock are not helpful because antiphysiological and potentially misleading. Hemorrhagic shock needs to be reclassified in the direction of usefulness and timing of intervention: in particular its assessment and management need to be tailored to physiology.

  1. INTERFERENCE OF COUNTERPROPAGATING SHOCK WAVES

    Directory of Open Access Journals (Sweden)

    P. V. Bulat

    2015-03-01

    Full Text Available The subject of study. We examined the interaction of counterpropagating shock waves. The necessity of counterpropagating shock waves studying occurs at designing of high Mach number modern internal compression air intakes, Ramjets with subsonic and supersonic combustion, in asymmetrical supersonic nozzles and in some other cases. In a sense, this problem is a generalization of the case of an oblique shock reflection from the wall or from the plane of symmetry. With the renewed vigor, the interest to this problem emerged at the end of the 90s. This was due to the start of the programs for flight study at hypersonic speeds. The first experiments performed with air intakes, which realized the interaction of counterpropagating shock waves have shown that the change in flow velocity is accompanied by abrupt alteration of shock-wave structure, the occurrence of nonstationary and oscillatory phenomena. With an increase of flow velocity these phenomena undesirable for aircraft structure became more marked. The reason is that there are two fundamentally different modes of interaction of counterpropagating shock waves: a four-wave regular and a five-wave irregular. The transition from one mode to another can be nonstationary abrupt or gradual, it can also be accompanied by hysteresis. Main results. Criteria for the transition from regular reflection of counterpropagating shock waves to irregular are described: the criterion of von Neumann and the stationary Mach configuration criterion. We described areas in which the transition from one reflection type to another is possible only in abrupt way, as well as areas of possible gradual transition. Intensity dependences of the reflected shock waves from the intensity of interacting counterpropagating shocks were given. Qualitative pictures of shock-wave structures arising from the interaction of counterpropagating shock waves were shown. Calculation results of the intensity of outgoing gas

  2. Shocks in the Early Universe.

    Science.gov (United States)

    Pen, Ue-Li; Turok, Neil

    2016-09-23

    We point out a surprising consequence of the usually assumed initial conditions for cosmological perturbations. Namely, a spectrum of Gaussian, linear, adiabatic, scalar, growing mode perturbations not only creates acoustic oscillations of the kind observed on very large scales today, it also leads to the production of shocks in the radiation fluid of the very early Universe. Shocks cause departures from local thermal equilibrium as well as create vorticity and gravitational waves. For a scale-invariant spectrum and standard model physics, shocks form for temperatures 1  GeVUniverse as early as 10^{-30}  sec after the big bang.

  3. Is this septic shock? A rare case of distributive shock

    OpenAIRE

    Val-Flores,Luis Silva; Fior,Alberto; Santos, Ana; Reis, Lu?s; Bento, Lu?s

    2014-01-01

    The authors report a rare case of shock in a patient without significant clinical history, admitted to the intensive care unit for suspected septic shock. The patient was initially treated with fluid therapy without improvement. A hypothesis of systemic capillary leak syndrome was postulated following the confirmation of severe hypoalbuminemia, hypotension, and hemoconcentration - a combination of three symptoms typical of the disease. The authors discussed the differential diagnosis and also...

  4. Is this septic shock? A rare case of distributive shock.

    Science.gov (United States)

    Val-Flores, Luis Silva; Fior, Alberto; Santos, Ana; Reis, Luís; Bento, Luís

    2014-01-01

    The authors report a rare case of shock in a patient without significant clinical history, admitted to the intensive care unit for suspected septic shock. The patient was initially treated with fluid therapy without improvement. A hypothesis of systemic capillary leak syndrome was postulated following the confirmation of severe hypoalbuminemia, hypotension, and hemoconcentration--a combination of three symptoms typical of the disease. The authors discussed the differential diagnosis and also conducted a review of the diagnosis and treatment of the disease.

  5. Efecto de la adición de materia orgánica sobre la dinámica poblacional bacteriana del suelo en cultivos de papa y maíz

    OpenAIRE

    David García Ventocilla; Gloria Mamani Gamarra; Nicolás Román Cabello; Luis Suárez Salas; Ana Contreras Marín; Julio Malca Jauregui

    2012-01-01

    Se determinó el efecto de la fertilización orgánica sobre las poblaciones bacterianas del suelo en cultivos de papa y maíz durante la campaña agrícola 2008-2009 en terrenos de cuatro localidades del Valle del Mantaro: INIA Santa Ana (Huancayo), en la EEA El Mantaro (Jauja), Vista Alegre y Huayao (ambos en Chupaca). En estos lugares se instalaron parcelas experimentales de papa (Solanum tuberosum L. Var. Canchan) y maíz (Zea maíz L. Var. Cusco mejorado) bajo abonamiento orgánico (vacuno, ovino...

  6. Influencia de la vitamina E (Natural vs. Sintética) en dietas enriquecidas con ácido α-linolénico sobre la producción y composición de la leche de oveja

    OpenAIRE

    Pérez González, Roberto

    2017-01-01

    El objetivo de este trabajo ha sido comparar el efecto de la incorporación de vitamina E sintética frente a vitamina E natural en raciones ricas en ácido α-linolénico de ovejas en la fase intermedia de lactación, sobre la producción y composición de la leche producida. Para ello, se emplearon treinta y seis ovejas de raza Churra divididas en tres tratamientos experimentales de acuerdo con la ración que recibieron: Control (ración sin vitamina E), Sin-E (ración con 400 mg/kg de ...

  7. Efecto interactivo de la autoeficacia y el valor del incentivo sobre la reactividad fisiológica periférica ante la ejecución de una tarea cognitiva

    OpenAIRE

    Sanz Ruiz, Antoni

    1996-01-01

    El presente experimento tenía por objeto verificar el supuesto de interacción entre la autoeficacia y el valor del incentivo sobre la reactividad fisiológica periférica (autonómica y somática). 32 sujetos fueron asignados a los 4 grupos experimentales que surgen de combinar 2 condiciones de manipulación de la autoeficacia (alta o baja) con 2 condiciones de manipulación del valor del incentivo (alta o baja). Todos los sujetos efectuaron una tarea de concatenación de palabras asistida por orden...

  8. Efecto de la fertilización fosfatada con cachaza sobre la actividad microbiana del suelo y la absorción de fósforo en caña de azúcar (Saccharum spp.)

    OpenAIRE

    Saucedo Castillo, Orlando; Prado,Renato de Mello; Castellanos González, Leónides; Ely, Nahas; Silva Campos, Cid Naudi; Silva, Gilmara Pereira da [UNESP; Assis, Luis Carlos [UNESP

    2015-01-01

    El objetivo del trabajo fue evaluar el efecto de diferentes dosis de fertilizante fosfatado con la adición de cachaza sobre la actividad microbiana del suelo, y el contenido de fósforo en el suelo y en plantas de caña de azúcar. El experimento se condujo en condi- ciones de invernadero en Jaboticabal Brasil en 2013, usándose plántulas de caña de azúcar (variedad "CTC 05"). Las unidades experimentales estuvieron constituidas por macet...

  9. Shock, ¿qué hay de nuevo?

    Directory of Open Access Journals (Sweden)

    Marta Sofía López Rodríguez

    2003-03-01

    Full Text Available El shock es un síndrome común de diversas causas que se inicia por una disminución de la perfusión hística, donde la microcirculación tiene una función crítica. En estudios recientes se profundiza en la terapéutica que debe ser inmediata, pues amenaza la vida e incluye: soporte respiratorio, soporte circulatorio, monitoreo metabólico, hemodinámica y tratamiento específico. El uso de cristaloides versus coloides es controversial y depende del criterio del médico. Se evidencia la utilidad de la amrinona (ionotropo, sobre todo en pacientes en shock séptico, y como vasopresor la vasopresina. El monitoreo de la concentración plasmática del ácido láctico es necesario por su relación con la mortalidad por shock. La mortalidad del shock séptico, a pesar de múltiples investigaciones, continúa elevada. Los inhibidores de la óxido-nítrico sintasa (S metil-isiotiourea de reciente utilización, parece alentador al inhibir la isoforma inducible (iNOS y de igual forma la inmunoterapia, pero se necesitan de nuevos estudios para evaluar su eficacia clínicaShock is a commom syndrome originated by different causes that starts with a decrease of histic perfusion, where macrocirculation has a critical function. In recent studies, emphasis has been made on the fact that therapeutics should be immediate in the face of this life menace and should include respiratory support, circulatory support, metabolic monitoring, hemodynamics and specific treatment. The use of crystalloids versus colloids is controversial and depends on the medical criterion. The usefulness of amrinone (ionotrope, mainly in patients with septic shock, and of vasopressin as a vasopressor is proved. The monitoring of the plasmatic concentration of the lactic acid is necessary due to its relation with mortality from shock. The mortality from septic shock is still high, in spite of the multiple investigations made. The recent utilization of nitric oxide synthase (S methyl

  10. Coping with shocks in rural Ethiopia

    NARCIS (Netherlands)

    Debebe, Z.Y.; Mebratie, A.; Sparrow, R.; Abebaw, D.; Dekker, M.; Alemu, G.; Bedi, A.S.

    2013-01-01

    Based on household survey data and event history interviews undertaken in a highly shock prone country, this paper investigates which shocks trigger which coping responses and why? We find clear differences in terms of coping strategies across shock types. The two relatively covariate shocks, that

  11. Critical Heart Failure and Shock.

    Science.gov (United States)

    Bronicki, Ronald A; Taylor, Mary; Baden, Harris

    2016-08-01

    The objectives of this review are to discuss the clinical assessment, pathophysiology, and management of shock, with an emphasis on circulatory physiology, cardiopulmonary interactions, and pharmacologic strategies to optimize systemic oxygen delivery. These principles will then be applied to the clinical syndromes of heart failure and cardiogenic shock that are seen in children. MEDLINE, PubMed. An understanding of essential circulatory physiology and the pathophysiology of shock are necessary for managing patients at risk for or in a state of shock. A timely and accurate assessment of cardiac function, cardiac output, and tissue oxygenation and the means by which to enhance the relationship between oxygen delivery and consumption are essential in order to optimize outcomes.

  12. Electric Shock Injuries in Children

    Science.gov (United States)

    ... Issues Listen Español Text Size Email Print Share Electric Shock Injuries in Children Page Content ​When the ... comes into direct contact with a source of electricity, the current passes through it, producing what's called ...

  13. Shock Thermodynamic Applied Research Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Shock Thermodynamic Applied Research Facility (STAR) facility, within Sandia’s Solid Dynamic Physics Department, is one of a few institutions in the world with a...

  14. Shock structure in massless gases

    Directory of Open Access Journals (Sweden)

    Armando Majorana

    1991-05-01

    Full Text Available The shock structure problem is investigated in the framework of the Eckart theory of irreversible thermodynamics in the ultra relativistic limit. It is considered a neutrino gas and a gas in the approximation of hard sphere model.

  15. ‘¿A qué sabe la luna?’ : un proyecto para aprender ciencias experimentales en Educación Infantil

    OpenAIRE

    Jiménez Martín, Cristina

    2015-01-01

    El principal objetivo de este trabajo es acercar al aula de Educación Infantil las ciencias experimentales a partir de la metodología por proyectos y teniendo como temática la luna. Este proyecto está dirigido al primer curso del segundo ciclo de la etapa de Educación Infantil, es decir, edades comprendidas entre los 3 y los 4 años. En este trabajo se expondrán las ideas principales de algunos de los autores más relevantes en educación, así como la metodología que se llevará a cabo, l...

  16. El rol de los valores numéricos de las medidas experimentales en el aprendizaje por indagación

    Directory of Open Access Journals (Sweden)

    Javier ARLEGUI DE PABLOS

    2010-01-01

    Full Text Available El aprendizaje por indagación en ciencias experimentales se entiende como un aprendizaje de resolución de problemas basado en la construcción y uso de modelos, y tiene actualmente su modelización didáctica en la teoría de las organizaciones praxeológicas. En este marco, los valores numéricos de las medidas juegan un papel preciso y de suma importancia; actúan como herramienta (útil en la construcción semántica de las magnitudes del fenómeno, y como objeto de conocimiento en el proceso de modelización de dicho fenómeno. Se muestra esta doble función en el caso de la elasticidad de un resorte.

  17. Bases fisiológicas experimentales para el estudio de la patogenia de los temblores en la enfermedad de parkinson

    OpenAIRE

    Esguerra Gómez, Alfonso; Matallana T., Alfonso; Montes D., Gonzalo

    2011-01-01

    Se presenta un estudio experimental sobre el fenómeno de la "contracción prosténica" del músculo gastrocnemio de la rana o "tétanos rítmico" de C. Richet. Finalmente, se presenta un análisis comparativo de las condiciones halladas en Fisiología humana para sugerir la posibilidad de encontrar en los casos clínicos de temblores una patogenia semejante al mecanismo de producción del tétanos rítmico experimental.

  18. SHOCK-WAVE VELOCITY AND SHOCK PRESSURE FOR LOW-DENSITY POWDERS - A NOVEL-APPROACH

    NARCIS (Netherlands)

    DIJKEN, DK; DEHOSSON, JTM

    1994-01-01

    A novel approach is presented to predict the shock wave velocity as well as the shock wave pressure in powder materials. It is shown that the influence of the specific volume behind the shock wave on shock wave velocity and shock pressure decreases with decreasing initial powder density. The new

  19. Shock wave velocity and shock pressure for low density powders : A novel approach

    NARCIS (Netherlands)

    Dijken, D.K.; Hosson, J.Th.M. De

    1994-01-01

    A novel approach is presented to predict the shock wave velocity as well as the shock wave pressure in powder materials. It is shown that the influence of the specific volume behind the shock wave on shock wave velocity and shock pressure decreases with decreasing initial powder density. The new

  20. Theoretical Insight into Shocked Gases

    Energy Technology Data Exchange (ETDEWEB)

    Leiding, Jeffery Allen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-09-29

    I present the results of statistical mechanical calculations on shocked molecular gases. This work provides insight into the general behavior of shock Hugoniots of gas phase molecular targets with varying initial pressures. The dissociation behavior of the molecules is emphasized. Impedance matching calculations are performed to determine the maximum degree of dissociation accessible for a given flyer velocity as a function of initial gas pressure.

  1. Acoustic shock injury (ASI).

    Science.gov (United States)

    Westcott, Myriam

    2006-12-01

    The potential severity and persistence of ASI symptoms has significant clinical and medico-legal implications. With the rapid growth of call centres around the world, professionals providing tinnitus and hyperacusis therapy are increasingly likely to encounter some or all of the cluster of ASI symptoms in their clients. Acoustic shock injury (ASI), occurring as a result of exposure to a sudden unexpected loud sound, has been observed to cause a specific and consistent pattern of neurophysiological and psychological symptoms. These include aural pain, tinnitus, hyperacusis/phonophobia, vertigo and other unusual symptoms such as numbness or burning sensations around the ear. A range of emotional reactions including trauma, anxiety and depression can develop. Call centre staff using a telephone headset or handset are vulnerable to ASI because of the increased likelihood of exposure, close to their ear(s), of sudden unexpected loud sounds randomly transmitted via the telephone line. This paper presents an overview of a study of 103 people exposed to 123 acoustic incidents, and of the proposed neurophysiological mechanism of ASI, in particular tonic tensor tympani syndrome (TTTS). An understanding of TTTS has the potential to provide insight into the neurophysiological and psychological development of tinnitus and hyperacusis and the association with high levels of emotional trauma and anxiety. ASI rehabilitation is discussed.

  2. Management of Shock in Neonates.

    Science.gov (United States)

    Bhat, B Vishnu; Plakkal, Nishad

    2015-10-01

    Shock is characterized by inadequate oxygen delivery to the tissues, and is more frequent in very low birth weight infants, especially in the first few days of life. Shock is an independent predictor of mortality, and the survivors are at a higher risk of neurologic impairment. Understanding the pathophysiology helps to recognize and classify shock in the early compensated phase and initiate appropriate treatment. Hypovolemia is rarely the primary cause of shock in neonates. Myocardial dysfunction is especially common in extremely preterm infants, and in term infants with perinatal asphyxia. Blood pressure measurements are easy, but correlate poorly with cerebral and systemic blood flows. Point-of-care cardiac ultrasound can help in individualized assessment of problems, selecting appropriate therapy and monitoring response, but may not always be available, and long-term benefits need to be demonstrated. The use of near-infrared spectroscopy to guide treatment of neonatal shock is currently experimental. In the absence of hypovolemia, excessive administration of fluid boluses is inappropriate therapy. Dobutamine and dopamine are the most common initial inotropes used in neonatal shock. Dobutamine has been shown to improve systemic blood flow, especially in very low birth weight infants, but dopamine is better at improving blood pressure in hypotensive infants. Newer inodilators including milrinone and levosimendan may be useful in selected settings. Data on long-term survival and neurologic outcomes following different management strategies are scarce and future research efforts should focus on this.

  3. Focusing of Shear Shock Waves

    Science.gov (United States)

    Giammarinaro, Bruno; Espíndola, David; Coulouvrat, François; Pinton, Gianmarco

    2018-01-01

    Focusing is a ubiquitous way to transform waves. Recently, a new type of shock wave has been observed experimentally with high-frame-rate ultrasound: shear shock waves in soft solids. These strongly nonlinear waves are characterized by a high Mach number, because the shear wave velocity is much slower, by 3 orders of magnitude, than the longitudinal wave velocity. Furthermore, these waves have a unique cubic nonlinearity which generates only odd harmonics. Unlike longitudinal waves for which only compressional shocks are possible, shear waves exhibit cubic nonlinearities which can generate positive and negative shocks. Here we present the experimental observation of shear shock wave focusing, generated by the vertical motion of a solid cylinder section embedded in a soft gelatin-graphite phantom to induce linearly vertically polarized motion. Raw ultrasound data from high-frame-rate (7692 images per second) acquisitions in combination with algorithms that are tuned to detect small displacements (approximately 1 μ m ) are used to generate quantitative movies of gel motion. The features of shear shock wave focusing are analyzed by comparing experimental observations with numerical simulations of a retarded-time elastodynamic equation with cubic nonlinearities and empirical attenuation laws for soft solids.

  4. EFECTO DE LA TEMPERATURA SOBRE LAS PROPIEDADES VOLUMÉTRICAS DE ALCOHOLES ALIFÁTICOS EN SOLUCIONES ACUOSAS DILUIDAS.

    Directory of Open Access Journals (Sweden)

    Carmen M. Romero

    2009-05-01

    Full Text Available La influencia de la temperatura sobre las propiedades volumétricas de soluciones acuosas ha sido frecuentemente usada para obtener información sobre los efectos de los distintos solutos sobre la estructura del agua.En este trabajo se presentan los resultados experimentales de densidades de soluciones acuosas diluidas de n-pentanol, n-hexanol, n-heptanol y n-octanol a 288,15; 293,15; 298,15; 303,15 y 308,15 K. Las medidas de densidad fueron realizadas en un densímetro Antón Paar de tubo vibracional (DMA 60/602 y a partir de los datos obtenidos se calcularon volúmenes de exceso, volúmenes molares aparentes y volúmenes molares parciales a dilución infinita. Para determinar el carácter hidrofóbico de los solutos empleados y su efecto sobre la estructura del agua se empleó el criterio de la segunda derivada del volumen molar parcial en función de la temperatura. Se calculó la contribución volumétrica del grupo CH2 encontrándose que tiene un valor constante en el rango de temperatura, estudiado.

  5. Generation and evolution of interplanetary slow shocks

    Directory of Open Access Journals (Sweden)

    C.-C. Wu

    1996-04-01

    Full Text Available It is well known that most MHD shocks observed within 1 AU are MHD fast shocks. Only a very limited number of MHD slow shocks are observed within 1 AU. In order to understand why there are only a few MHD slow shocks observed within 1 AU, we use a one-dimensional, time-dependent MHD code with an adaptive grid to study the generation and evolution of interplanetary slow shocks (ISS in the solar wind. Results show that a negative, nearly square-wave perturbation will generate a pair of slow shocks (a forward and a reverse slow shock. In addition, the forward and the reverse slow shocks can pass through each other without destroying their characteristics, but the propagating speeds for both shocks are decreased. A positive, square-wave perturbation will generate both slow and fast shocks. When a forward slow shock (FSS propagates behind a forward fast shock (FFS, the former experiences a decreasing Mach number. In addition, the FSS always disappears within a distance of 150R⊙ (where R⊙ is one solar radius from the Sun when there is a forward fast shock (with Mach number ≥1.7 propagating in front of the FSS. In all tests that we have performed, we have not discovered that the FSS (or reverse slow shock evolves into a FFS (or reverse fast shock. Thus, we do not confirm the FSS-FFS evolution as suggested by Whang (1987.

  6. When shock is shocked: Riemann problem dynamics at pulse ionization of a shock wave

    Science.gov (United States)

    Doroshchenko, Igor; Znamenskaya, Irina; Koroteev, Dmitry; Kuli-zade, Tahir

    2017-10-01

    We study the dynamics of the gas flow discontinuities after pulse ionization of a half space in front of a flat shock wave moving in a channel. Pulse volumetric electric discharge initiated in the vicinity of the shock concentrates in front of the shock and heats the gas there. The heating is shown to be very rapid. We use the shadow imaging technique and a high speed camera to study the flow pattern evolution after the discharge. The pattern consists of two shocks separated by a contact surface. This structure corresponds to the classical Riemann problem formulation. Based on the observed pattern, we estimate the amount of discharge energy converted to heat during the discharge time: the rate of temperature increase is in the order of several degrees K per nanosecond.

  7. Foros: Verdades y Mitos sobre las Células Madre (CM.

    Directory of Open Access Journals (Sweden)

    Efraím Otero Ruiz

    2005-09-01

    La Dra. Martalucía Tamayo dijo que por su experiencia individual podría asumir ella los tres roles como investigadora, como paciente y como periodista. Como investigadora, sostiene que la experimentación debe basarse en el método científico y debe cumplir no sólo con la apropiación social del conocimiento sino también sus relaciones adecuadas con la sociedad (pacientes, familias y con los medios de comunicación masiva. En el caso de las CM, embrionarias o adultas debe advertirse que las terapias posibles son aún experimentales y con ese carácter deben tener impacto en su legislación; esas fases experimentales deben incluir microbiología, ensayos en animales pequeños y grandes para luego pasar a humanos y en esta última fase ser controladas por entes como lo hace la FDA en los Estados Unidos, pero persiste el interrogante de cómo controlar ectivamente los modelos humanos. Deben balancearse los beneficios en lo personal vs. lo social, evaluar los costos individuales y sobre los sistemas de salud. Como paciente prefiere que se definan bien los beneficiarios potenciales, explicarles las posibilidades reales del procedimiento incluyendo riesgos y costos, aceptando con esperanza y firmeza tanto su enfermedad como cualquier solución que se les prometa. Cree que deben establecerse asociaciones de pacientes que evalúen tanto las expectativas, reales o falsas como los costos sociales y económicos, ya que las falsas esperanzas pueden traducirse en más frustración para los mismos...

  8. Cardiogenic shock: management of right ventricular infarction shock.

    Science.gov (United States)

    Ruiz Bailén, M; Ruiz García, M I; Ferrezuelo Mata, A; Quirós Barrera, R

    2012-04-01

    Right ventricular infarction is a not uncommon cause of cardiogenic shock, whose frecuency is variable and could be underestimated. Although left ventricular myocardial management is well defined in the right ventricular infarction are few studies with low level of evidence, to establish definitive guidelines. It is assumed that the treatment is similar to that of the left ventricle, although there are some differences. The axis of the therapeutic management, as well as the left ventricle infarction, is based on early myocardial reperfusion, particularly through percutaneous coronary interventionism. Throm-bolysis is an option, especially after an increase in systemic blood pressure using vasoactive drugs such as norepinephrine. The preload optimization by volume administration during resuscitation of shock is useful, but it must be with caution. The use of levosimendan could be potentially beneficial option. On the neurohormonal modulation of systemic inflammatory response produced after the cardiogenic shock (CS), the use of ACE inhibitors and beta-blockers is controversial.

  9. [Shock in obstetrics. Institutional experience].

    Science.gov (United States)

    Bonfante Ramírez, E; Ahued Ahued, R; García-Benítez, C Q; Bolaños Ancona, R; Callejos, T; Juárez García, L

    1997-04-01

    Shock is one of the most difficult problems an obstetrician can face. Hemorrhage is the main reason of shock. A descriptive and retrospective research was conducted at Instituto Nacional de Perinatología, from January 1992 to May 1996, including all patients admitted to the intensive care unit with diagnosis of shock. There were found 90 cases with diagnosis of shock, 82 were hipovolemic, and 8 cases had the septic kind of shock. The average of age was 32.2 years, with a gestational age between 6.2 to 41.4 weeks . There were 71 healthy patients, hypertension was associated to pregnancy in 9 cases, infertility in two, myomatosis in 2, and diabetes in 2 more patients. Other 5 cases reported different pathologies. The most frequent cause for hipovolemic shock resulted to be placenta acreta (40 cases), followed by uterine tone alterations in 37 patients, ectopic pregnancy in 7, uterine rupture or perforation in 4, and vaginal or cervical lacerations in 2. The estimated blood loss varied from 2200 cc to 6500 cc, and the minimal arterial pressure registered during shock was between 40/20 mmHg to 90/60 mmHg. Medical initial assistance consisted in volume reposition with crystalloids, globular packages, and plasma expansors in 73 patients (81.1%). The rest of the patients received in addition coloids, platelets and cryoprecipitates. A total of 76 patients required surgical intervention consisting in total abdominal hysterectomy. In 5 cases the previous surgical procedure was done and ligation of hypogastric vessels was needed. Salpingectomy was performed in 5 patients, and rupture or perforation repair in 3. The average surgery time was 2 hours and 33 minutes. The observed complications were 7 cases with abscess of the cupula, consumption coagulopathy in 2, 1 vesical quirurgical injury, 1 intestinal occlusion, and 11 vesico-vaginal fistula. The average days of hospitalization resulted to be 5. The most frequent kind of shock seen by obstetricians is the hipovolemic type

  10. Inappropriate shocks in the subcutaneous ICD

    DEFF Research Database (Denmark)

    Olde Nordkamp, Louise R A; Brouwer, Tom F; Barr, Craig

    2015-01-01

    months, 48 out of 581 S-ICD patients (71% male, age 49 ± 18 years) experienced 101 inappropriate shocks (8.3%). The most common cause was cardiac signal oversensing (73%), such as T-wave oversensing. Eighteen shocks (18%) were due to supraventricular tachycardias (SVT), of which 15 occurred in the shock...... xyphoid to V6) reduced the risk. Reprogramming or optimization of SVT treatment after the first clinical event of inappropriate shock was successful in preventing further inappropriate shocks for cardiac oversensing and SVT events. CONCLUSIONS: Inappropriate shocks, mainly due to cardiac oversensing...

  11. Pressure Hull Analysis under Shock Loading

    Directory of Open Access Journals (Sweden)

    Ya-Jung Lee

    2008-01-01

    Full Text Available The hull of high performance submarines must resist underwater shock loading due to exploding torpedoes or depth bombs. An underwater shock involving an initial shock wave and successive bubble pulsating waves is so complex that a theoretical technique for deriving shock pressure distribution is required for improving simulation efficiency. Complete shock loading is obtained theoretically in this work, and responses of a submarine pressure hull are calculated using ABAQUS USA (Underwater Shock Analysis codes. In the long run, this deflection and stress data will assist in examining the structural arrangement of the submarine pressure hull.

  12. Shock compression of simulated adobe

    Science.gov (United States)

    Braithwaite, C. H.; Church, P. D.; Gould, P. J.; Stewart, B.; Jardine, A. P.

    2017-01-01

    A series of plate impact experiments were conducted to investigate the shock response of a simulant for adobe, a traditional form of building material widely used around the world. Air dried bricks were sourced from the London brick company, dry machined and impacted at a range of velocities in a single stage gas gun. The shock Hugoniot was determined (Us =2.26up+0.37) as well as release information. The material was found to behave in a manner which was similar to that of loose sand and considerably less stiff than a weak porous sandstone. The effect of any cementing of the grains was examined by shocking powdered samples contained within a cell arrangement.

  13. Shock compression of liquid hydrazine

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, B.O. [Los Alamos National Lab., NM (United States); Chavez, D.J. [Rockwell White Sands Test Facility, Las Cruces, NM (United States)

    1995-01-01

    Liquid hydrazine (N{sub 2}H{sub 4}) is a propellant used by the Air Force and NASA for aerospace propulsion and power systems. Because the propellant modules that contain the hydrazine can be subject to debris impacts during their use, the shock states that can occur in the hydrazine need to be characterized to safely predict its response. Several shock compression experiments have been conducted in an attempt to investigate the detonability of liquid hydrazine; however, the experiments results disagree. Therefore, in this study, we reproduced each experiment numerically to evaluate in detail the shock wave profiles generated in the liquid hydrazine. This paper presents the results of each numerical simulation and compares the results to those obtained in experiment. We also present the methodology of our approach, which includes chemical kinetic experiments, chemical equilibrium calculations, and characterization of the equation of state of liquid hydrazine.

  14. TRADICIÓN INVESTIGATIVA Y CONSTRUCTOS PARA COMPRENDER ASPECTOS DE LA INSERCIÓN PROFESIONAL DOCENTE: PLURALISMO CULTURAL, ACULTURACIÓN, SHOCK CULTURAL (RESEARCH TRADITION AND CONSTRUCTS TO UNDERSTAND ASPECTS OF TEACHER PROFESSIONAL INTEGRATION: CULTURAL PLURALISM, ACCULTURATION, CULTURAL SHOCK

    Directory of Open Access Journals (Sweden)

    D' Antoni Maurizia

    2010-12-01

    Full Text Available Resumen:El fenómeno de la interculturalidad le impone a la academia cambios y reflexiones nuevas. En el presente ensayo reflexiono sobre los conceptos base que puedan guiar una investigación sobre inserción profesional de docentes extranjeros y extranjeras en la Universidad de Costa Rica (UCR. Sobresale el concepto de aculturación. Luego, tomo en cuenta el concepto de shock cultural y cómo Michael Winkelman resume la tradición de estudios sobre el tema, contrastándola con aportes de diversos estudiosos. Finalmente presento la visión de Paulo Freire, y de otros autores que comparten su visión del mundo, sobre qué es cultura y me sirvo de su aporte para analizar críticamente el concepto de shock cultural. Concluyo que, a pesar de la utilidad que puedan tener conceptos como shock cultural o inteligencia cultural, interesa más una visión de la cultura que tenga como punto de referencia el contexto.Abstract:The phenomenon of multiculturalism imposes to the academic world changes and new ideas. In this essay I reflect on the basic concepts that can guide research on professional integration of foreign teachers at the University of Costa Rica. The concept of acculturation appears to be the most important. Then I take into account the concept of culture shock and how Michael Winkelman synthesizes the tradition of studies on the subject, contrasting that contribution with contributions from other authors. Finally I present the vision of Paulo Freire, and other authors who share his approach, on what culture is. I am using their input to critically analyze the concept of cultural shock. I conclude that, although concepts such as cultural shock or cultural intelligence may be helpful, more interested in a vision of culture that that has as its reference point the context.

  15. Shock Initiation of Damaged Explosives

    Energy Technology Data Exchange (ETDEWEB)

    Chidester, S K; Vandersall, K S; Tarver, C M

    2009-10-22

    Explosive and propellant charges are subjected to various mechanical and thermal insults that can increase their sensitivity over the course of their lifetimes. To quantify this effect, shock initiation experiments were performed on mechanically and thermally damaged LX-04 (85% HMX, 15% Viton by weight) and PBX 9502 (95% TATB, 5% Kel-F by weight) to obtain in-situ manganin pressure gauge data and run distances to detonation at various shock pressures. We report the behavior of the HMX-based explosive LX-04 that was damaged mechanically by applying a compressive load of 600 psi for 20,000 cycles, thus creating many small narrow cracks, or by cutting wedge shaped parts that were then loosely reassembled, thus creating a few large cracks. The thermally damaged LX-04 charges were heated to 190 C for long enough for the beta to delta solid - solid phase transition to occur, and then cooled to ambient temperature. Mechanically damaged LX-04 exhibited only slightly increased shock sensitivity, while thermally damaged LX-04 was much more shock sensitive. Similarly, the insensitive explosive PBX 9502 was mechanically damaged using the same two techniques. Since PBX 9502 does not undergo a solid - solid phase transition but does undergo irreversible or 'rachet' growth when thermally cycled, thermal damage to PBX 9502 was induced by this procedure. As for LX-04, the thermally damaged PBX 9502 demonstrated a greater shock sensitivity than mechanically damaged PBX 9502. The Ignition and Growth reactive flow model calculated the increased sensitivities by igniting more damaged LX-04 and PBX 9502 near the shock front based on the measured densities (porosities) of the damaged charges.

  16. Todo sobre el neobarroco

    Directory of Open Access Journals (Sweden)

    Arturo Carrera

    2007-07-01

    Full Text Available Lo que hemos escuchado y atendido hasta aquí, hoy, ayer, sobre todo en la propuesta poética esbozada por Sergio Raimondi en su ensayo sobre Aldo Oliva, demuestra que las singularidades, su pasión, anulan subrepticiamente las nominaciones.Anoche en la televisión una orquesta sinfónica y un coro numeroso. Súbitamente, me hubiera gustado ser uno de esos intérpretes solitarios para sí, a pesar de la armonía, anónimos, a pesar del brillo sonoro… un violín, un triángulo… apenas… tres grillos… como ...

  17. Estudos sobre a psicopatia

    OpenAIRE

    Peres, Kenia

    2008-01-01

    Esta dissertação é resultado de extensa pesquisa sobre a psicopatia, fenômeno psicopatológico tão recorrente no cotidiano social, porém pouco explorado, talvez pela indiscutível dificuldade técnica no manejo desses pacientes. O interesse em compreender o psicodinamismo desses indivíduos caminha paralelamente ao meu desenvolvimento profissional, tanto como pesquisadora como psicóloga clínica. Neste trabalho, utilizei além da pesquisa bibliográfica da teoria psicanalítica sobre o tema, estudos ...

  18. Supercriticality of ICME and CIR shocks

    Science.gov (United States)

    Zhou, Xiaoyan; Smith, Edward J.

    2015-03-01

    Interplanetary coronal mass ejection (ICME) and corotating interaction region (CIR) shocks are characterized in terms of supercriticality introduced by Edmiston and Kennel (1984) to classify shocks based on whether dissipation is provided by electron resistivity alone or also requires ion viscosity. The condition for determining supercriticality is a critical Mach number, MC, a function of θBn, the angle between the upstream magnetic field, B, and the normal to the shock surface, n, and β, the ratio of the plasma and magnetic pressures. The criterion was subsequently revised by Kennel (1987) to include dissipation by electron thermal as well as electrical conductivity. Two early separate studies of ICME and CIR shocks motivated our investigation that included several improvements. We use Kennel (1987) and shocks identified by WIND near 1 AU and by Ulysses near 5 AU from the same solar cycle to provide Occurrence Probability Distributions and statistical information for all parameters. We answer three questions (1) Is the supercriticality of ICME and CIR shocks different? (2) If so, why? (3) Does the latter MC criterion change the answers? Our conclusions are (1) about two thirds of CIR shocks are supercritical as compared to one third of ICME shocks, (2) although ICME shock speeds are typically higher than CIR shocks, the fast-mode wave speeds are even higher at 1 AU than that of CIR shocks at ~5 AU causing a reduction in Mach numbers, and (3) CIR shocks are also more supercritical than ICME shocks using both criteria with slight differences.

  19. Sepsis and Septic Shock Strategies.

    Science.gov (United States)

    Armstrong, Bracken A; Betzold, Richard D; May, Addison K

    2017-12-01

    Three therapeutic principles most substantially improve organ dysfunction and survival in sepsis: early, appropriate antimicrobial therapy; restoration of adequate cellular perfusion; timely source control. The new definitions of sepsis and septic shock reflect the inadequate sensitivity, specify, and lack of prognostication of systemic inflammatory response syndrome criteria. Sequential (sepsis-related) organ failure assessment more effectively prognosticates in sepsis and critical illness. Inadequate cellular perfusion accelerates injury and reestablishing perfusion limits injury. Multiple organ systems are affected by sepsis and septic shock and an evidence-based multipronged approach to systems-based therapy in critical illness results in improve outcomes. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Mesures experimentales de l'impact des revetements hydrophobeset superhydrophobes sur la trainee et la portance d'un profil aerodynamique propre et glace

    Science.gov (United States)

    Villeneuve, Eric

    Ce projet, realise a la demande du Laboratoire International des Materiaux Antigivre, a pour but de mesurer et definir experimentalement l'impact de revetements hydrophobes sur les coefficients de trainee et de portance d'un profil NACA 0012. Pour ce faire, la balance aerodynamique du LIMA devait tout d'abord etre amelioree afin d'offrir une sensibilite suffisante pour realiser le projet. Plusieurs ameliorations ont ete faites, comme le changement des cellules de charge, la diminution du nombre de cellules de charge, le changement du cadre de la balance, etc. Une fois ces ameliorations terminees, la reproductibilite, l'exactitude et la sensibilite ont ete valides afin de s'assurer de la fiabilite des resultats offerts par la balance. Pour les angles d'attaque etudies avec les revetements, soient -6° et 0°, la balance a une reproductibilite de +/-2,06% a 360 000 de nombre de Reynolds. Pour valider la sensibilite, des essais a -6° et 0° d'angle d'attaque et des nombres de Reynolds de 360 000 et 500 000 ont ete faits avec des papiers sables. Les resultats de ces essais ont permis de, tracer des courbes de tendances du coefficient de trainee du NACA 0012 en fonction de la rugosite de surface et d'etablir la valeur de la sensibilite de la balance a +/-8 mu m. Cinq revetements populaires ont ete choisis pour l'experimentation, soient le Wearlon, le Staclean, le Hirec, le Phasebreak ainsi que le Nusil. Les revetements sont soumis aux memes conditions experimentales que les papiers sables, et une rugosite equivalente est trouvee par extrapolation des resultats. Cependant, les rugosites equivalentes de surfaces different entre -6° et 0°. Les essais avec le Staclean et le Hirec donnent des coefficients de trainee equivalent a ceux avec l'aluminium, alors que le Wearlon, le Nusil et le Phasebreak donnent une augmentation du coefficient de trainee de 13%, 17% et 25% respectivement par rapport a l'aluminium. Pour les coefficients de portance, la balance ne detecte pas l

  1. Shock Ignition Sensitivity of Multiply-Shocked TNT

    Science.gov (United States)

    1982-07-01

    lated by the procedures outlined in the preceding section. The time duration of pressure at each level is simply the reverberation time of a shock wave in...propagate into the TNT sample. In some of our early firings where 3.2 m thick poly was used as the first plate (2psec reverberation time ) the second

  2. Shock Tubes and Shock Tunnels: Design and Experiments

    Science.gov (United States)

    2009-09-01

    evolution given by thin film platinum heat gauges mounted flush with the wall is given in Fig.12. Heat flux can be deduced from this type of recording...photography or cinematography [(x, t) or (y, t) diagrams]. Examples of shock tube flows are thus represented in Figs.14 and 15 [30]. (a

  3. Actividad molusquicida del Paraiso (Melia azedarach L. (Meliaceae sobre Lymnaea cubensis, molusco vector de Fasciolosis

    Directory of Open Access Journals (Sweden)

    Marlene Piña Perez

    1998-06-01

    Full Text Available INTRODUCCIÓN: La Fasciolosis constituye en diversas regiones una fuente importante de pérdidas económicas y cuando se descuidan las medidas de control de sus hospedadores (moluscos, junto a condiciones ecológicas favorables, pueden ocurrir casos aislados de Fasciolosis humana. Dentro de los métodos alternativos para su control está el uso de extractos vegetales y se pretendió evaluar el probable empleo del jugo extraído del fruto y semillas del Paraiso (Melia azedarach L. en el control de Lymnaea cubensis, principal vector de la Fasciolosis en Cuba. MATERIAL Y MÉTODO: Diferentes concentraciones del jugo extraído del fruto y semillas del Paraiso (Melia azedarach L. fueron testados para determinar las dosis letales media (DL50 y máxima (DL90 usando un programa computarizado Probit-Log. Siete series experimentales fueron probadas usando 72 moluscos en cada una. Para determinar la influencia sobre la frecuencia cardíaca fueron testados tres grupos de 10 moluscos, dos fueron tratados con las DL50=0,88627 y DL90=1,7641, respectivamente, mientras que el tercero fue considerado como testigo. RESULTADOS Y CONCLUSIONES: Se observó una marcada influencia de ambas dosis sobre la frecuencia cardíaca del molusco estudiado. Estos resultados son alentadores, pues demuestran el potencial empleo de esta planta en el control de moluscos indeseables.

  4. Actividad molusquicida del Paraiso (Melia azedarach L. (Meliaceae sobre Lymnaea cubensis, molusco vector de Fasciolosis

    Directory of Open Access Journals (Sweden)

    Perez Marlene Piña

    1998-01-01

    Full Text Available INTRODUCCIÓN: La Fasciolosis constituye en diversas regiones una fuente importante de pérdidas económicas y cuando se descuidan las medidas de control de sus hospedadores (moluscos, junto a condiciones ecológicas favorables, pueden ocurrir casos aislados de Fasciolosis humana. Dentro de los métodos alternativos para su control está el uso de extractos vegetales y se pretendió evaluar el probable empleo del jugo extraído del fruto y semillas del Paraiso (Melia azedarach L. en el control de Lymnaea cubensis, principal vector de la Fasciolosis en Cuba. MATERIAL Y MÉTODO: Diferentes concentraciones del jugo extraído del fruto y semillas del Paraiso (Melia azedarach L. fueron testados para determinar las dosis letales media (DL50 y máxima (DL90 usando un programa computarizado Probit-Log. Siete series experimentales fueron probadas usando 72 moluscos en cada una. Para determinar la influencia sobre la frecuencia cardíaca fueron testados tres grupos de 10 moluscos, dos fueron tratados con las DL50=0,88627 y DL90=1,7641, respectivamente, mientras que el tercero fue considerado como testigo. RESULTADOS Y CONCLUSIONES: Se observó una marcada influencia de ambas dosis sobre la frecuencia cardíaca del molusco estudiado. Estos resultados son alentadores, pues demuestran el potencial empleo de esta planta en el control de moluscos indeseables.

  5. Observaciones en el Ornithodoros Forcosus sobre su posible rol como vector de la Fiebre Recurrente

    Directory of Open Access Journals (Sweden)

    Arístides Herrer

    1957-12-01

    Full Text Available Tratando de verificar la posible infección por borrelias en el Ornithodoros Forcosus Neumann, 1908, se realizaron observaciones experimentales en las que se utilizó un total de 1,655 especímenes de esta garrapata. En tales estudios se emplearon pericotes blancos y cobayos. Con triturado de garrapatas fueron inoculados 68 animales (64 pericotes y 4 cobayos y 37 (16 pericotes y 21 cobayos fueron empleados para alimentar sobre ellos varios lotes de garrapatas. Los resultados de todas estas observaciones fueron negativas. Las garrapatas con las que se han efectuado estos estudios procedían de las localidades de Limabamba, Mariscal Benavides, Camporredondo, Ocalli y Luya, todas en el departamento de Amazonas, y a altitudes que varían entre 1,400 y 2,300 metros sobre el nivel del mar. Desde que la fiebre recurrente parece ser endémica en el Perú, especialmente en localidades de considerable altitud, es de suponer que en este país sea trasmitida principalmente por piojos.

  6. FILOSOFIA DE LA MENTE; APORTES TEORICOS Y EXPERIMENTALES A LA VISIÓN EMERGENTISTA DEL VINCULO MENTE-CEREBRO.

    Directory of Open Access Journals (Sweden)

    Paul Ruiz Santos

    2011-01-01

    Full Text Available El presente trabajo intenta sumar alprograma emergentista dentro del mapa teórico referido a la Filosofía de la Mente, tomando como referentes a disciplinas y teorías naturalizadas. Algunos puentes vinculantes desde la naturalización pueden ser por ejemplo el neuro-psicoanálisis, las neuronas espejo, la psicosomática, entre otros. Dichos puentes son posibles de ser tendidos a través de la naturalización de los procesos psicológicos vinculándolos a diferentes procesos biológicos. El objetivo del trabajo no pretende obturar los procesos psicológicos a través de la simplificación y reduccionismo de los mismos, ni biologizar la psicología a través de planteos cartesianos. Sino, de la mano de la neuro-fenomenología, acceder a más y nuevas evidencias sobre el vínculo mente-cerebro y sus implicancias aportando a una visión interaccionista y emergentista del vínculo.

  7. Particle drift, diffusion, and acceleration at shocks

    Science.gov (United States)

    Jokipii, J. R.

    1982-01-01

    The gradient and curvature drifts implicit in change of the ambient magnetic field at a hydromagnetic shock wave are incorporated into the diffusive theory of shock acceleration of charged particles. The conventional jump condition at the shock is modified by a term incorporating the large drift along the shock plane. This term vanished identically for one-dimensional systems, but must be included in general for shocks which are finite in transverse extent or which have transverse structure. It is found that the effect of the drift is such that the transverse drift rate is proportional to the acceleration rate, and for perpendicular shocks is exactly equal to the rate of change of energy in the V x B electric field observed in the shock frame. This establishes a connection with the 'shock drift' models which neglect diffusion.

  8. Shock dynamics in layered periodic media

    KAUST Repository

    Ketcheson, David I.

    2012-01-01

    Solutions of constant-coeffcient nonlinear hyperbolic PDEs generically develop shocks, even if the initial data is smooth. Solutions of hyperbolic PDEs with variable coeffcients can behave very differently. We investigate formation and stability of shock waves in a one-dimensional periodic layered medium by a computational study of time-reversibility and entropy evolution. We find that periodic layered media tend to inhibit shock formation. For small initial conditions and large impedance variation, no shock formation is detected even after times much greater than the time of shock formation in a homogeneous medium. Furthermore, weak shocks are observed to be dynamically unstable in the sense that they do not lead to significant long-term entropy decay. We propose a characteristic condition for admissibility of shocks in heterogeneous media that generalizes the classical Lax entropy condition and accurately predicts the formation or absence of shocks in these media.

  9. Shock State of Itokawa Regolith Grains

    Science.gov (United States)

    Zolensky, M.; Nishiizumi, K.; Mikouchi, T.; Chan, Q. H. S.; Martinez, J.; Caffee, M.

    2014-01-01

    One of the fundamental aspects of any astromaterial is its shock history, since this factor elucidates critical historical events, and also because shock metamorphism can alter primary mineralogical and petrographic features, and reset chronologies.

  10. Kinetic Simulations of Particle Acceleration at Shocks

    Energy Technology Data Exchange (ETDEWEB)

    Caprioli, Damiano [Princeton University; Guo, Fan [Los Alamos National Laboratory

    2015-07-16

    Collisionless shocks are mediated by collective electromagnetic interactions and are sources of non-thermal particles and emission. The full particle-in-cell approach and a hybrid approach are sketched, simulations of collisionless shocks are shown using a multicolor presentation. Results for SN 1006, a case involving ion acceleration and B field amplification where the shock is parallel, are shown. Electron acceleration takes place in planetary bow shocks and galaxy clusters. It is concluded that acceleration at shocks can be efficient: >15%; CRs amplify B field via streaming instability; ion DSA is efficient at parallel, strong shocks; ions are injected via reflection and shock drift acceleration; and electron DSA is efficient at oblique shocks.

  11. The microphysics of collisionless shock waves

    DEFF Research Database (Denmark)

    Marcowith, Alexandre; Bret, Antoine; Bykov, Andrei

    2016-01-01

    galactic nuclei, gamma-ray bursts and clusters of galaxies shock waves. Collisionless shock microphysics enters at different stages of shock formation, shock dynamics and particle energization and/or acceleration. It turns out that the shock phenomenon is a multi-scale non-linear problem in time and space....... A particular emphasis is made on the different instabilities triggered during the shock formation and in association with particle acceleration processes with regards to the properties of the background upstream medium. It appears that among the most important parameters the background magnetic field through...... in the physics of space plasma and astrophysical shock waves. A special section is dedicated to new laser plasma experiments probing shock physics....

  12. Early Treatment of Shock and Injury

    Science.gov (United States)

    2013-10-01

    Resuscitation from Shock. FELANPE, Federation Latinoamericana de Terapia Nutricional, Nutrition Clinica, y Metabolisma. October 5, 2011. (Asuncion...Resuscitation from Shock. FELANPE, Federation Latinoamericana de Terapia Nutricional, Nutrition Clinica, y Metabolisma. October 5, 2011

  13. Etiology of Shock in the Emergency Department

    DEFF Research Database (Denmark)

    Holler, Jon Gitz; Jensen, Helene Kildegaard; Henriksen, Daniel Pilsgaard

    2018-01-01

    were included. Discharge diagnoses defined the etiology and were grouped as; distributive septic shock (SS), distributive non-septic shock (NS)), cardiogenic shock (CS), hypovolemic shock (HS), obstructive shock (OS) and other conditions (OC). Outcomes were etiology-based characteristics, annual IR per......INTRODUCTION: The knowledge of the etiology and associated mortality of undifferentiated shock in the emergency department (ED) is limited. We aimed to describe the etiology based proportions and incidence rates (IR) of shock, as well as the associated mortality in the ED. METHODS: Population......-based cohort study at an University Hospital ED in Denmark from January 1, 2000, to December 31, 2011. Patients aged ≥18 years living in the ED-catchment area (N = 225,000) with a first time ED presentation with shock (n = 1,646) defined as hypotension (systolic blood pressure ≤100 mmHg)) and ≥1 organ failures...

  14. [Epidemiological data on shock in forensic medicine].

    Science.gov (United States)

    Manoilescu, Irina; Teleman, S; Mihăilă, Doina; Cojocaru, Elena; Plămădeală, P

    2010-01-01

    The shock is a relative frequent diagnostic in forensic medicine. We realized a statistical study, using 323 deaths through diverse shock typology, registered within the Forensic Medicine Institute of Iaşi in 2000-2009. The concerned variables were: the spread of cases on years, the clinical forms, age, sex, provenience environment, volemic feature, the survival time from the shock to the death, the spread of complications on the form of the shock and survival, the juridical way of death. Our data were introduced in the EXCEL database and statisticaly analyzed by SPSS program. We obtained statistic data on shock typology, based on the survival time and based on the complications of shock types. Relevant statistic data were obtained on the relations between the factors that generated the shock, the complications induced and the shock types, related also to the juridical way of death.

  15. 29th International Symposium on Shock Waves

    CERN Document Server

    Ranjan, Devesh

    2015-01-01

    This proceedings present the results of the 29th International Symposium on Shock Waves (ISSW29) which was held in Madison, Wisconsin, U.S.A., from July 14 to July 19, 2013. It was organized by the Wisconsin Shock Tube Laboratory, which is part of the College of Engineering of the University of Wisconsin-Madison. The ISSW29 focused on the following areas: Blast Waves, Chemically Reactive Flows, Detonation and Combustion,  Facilities, Flow Visualization, Hypersonic Flow, Ignition, Impact and Compaction, Industrial Applications, Magnetohydrodynamics, Medical and Biological Applications, Nozzle Flow, Numerical Methods, Plasmas, Propulsion, Richtmyer-Meshkov Instability, Shock-Boundary Layer Interaction, Shock Propagation and Reflection, Shock Vortex Interaction, Shock Waves in Condensed Matter, Shock Waves in Multiphase Flow, as well as Shock Waves in Rarefield Flow. The two Volumes contain the papers presented at the symposium and serve as a reference for the participants of the ISSW 29 and individuals interes...

  16. SHOCK WAVE IN IONOSPHERE DURING EARTHQUAKE

    Directory of Open Access Journals (Sweden)

    V.V. Kuznetsov

    2016-11-01

    Full Text Available Fundamentally new model of the shock wave (SW generation in atmosphere and ionosphere during earthquake is proposed. The model proceeds from the idea of cooperative shock water crystallization in a cloud

  17. Etude experimentale des excitations topologiques de l'effet Hall quantique a nu = 1 dans les heterostructures semiconductrices a double puits quantique

    Science.gov (United States)

    Charlebois, Serge

    De nombreux travaux theoriques et experimentaux ont ete publies sur les excitations topologiques de gaz electroniques bidimensionnels (GE2D), appellees skyrmions, dans le regime de l'effet Hall quantique a remplissage unitaire. On attend des excitations semblables appellees bimerons dans les systemes formes de deux GE2D couples. Contrairement au cas des GE2D simples, aucune experience n'a, a notre connaissance, presente la mesure d'une propriete specifique aux bimerons. Nous presentons dans cette these des travaux experimentaux ayant pour objectif l'etude d'excitations topologiques dans les heterostructures a double puits quantique. Une manifestation attendue (les bimerons est la presence d'une anisotropie dans la conductivite a travers une constriction. Nous avons concu un dispositif original a point de contact a trois grilles non-coplanaires. Ce dispositif a trois grilles a la particularite de permettre la creation d'une constriction etroite dans le double GE2D tout en permettant l'equilibrage de la densite electronique entre les deux puits dans l'etroit canal de conduction. Nous avons fabrique ce dispositif de taille submicronique par electrolithographie sur des heterostructures a double puits. Les dispositifs ainsi fabriques ont ete etudies a basse temperature (0.3K) et ont montre un fonctionnement conforme aux attentes. Les travaux n'ont pas permis de mettre en evidence une anisotropie de transport revelatrice de l'existence de bimerons. Cette these est a notre connaissance la premiere etude experimentale visant la realisation de l'experience d'anisotropie de transport et est ainsi une contribution significative a l'avancement des connaissances dans ce domaine. Les travaux theoriques que nous presentons ont permis de montrer l'effet des excitations topologiques sur la capacite grille-GE2D du systeme. Ces travaux ouvrent la voie de la detection des bimerons par l'intermediaire de la mesure de la capacite grille-GE2D ou encore de la susceptibilite electrique du

  18. Bloqueo de las crisis audiogénicas y del choque electroconvulsivo por la 2-fenil-4,4-bis-(hidroximetil-2-oxazolina Block of the audiogenic seizures and of the electroconvulsive shock by 2-phenyl-4, 4-bis-(hydroxymethyl-2-oxazoline

    Directory of Open Access Journals (Sweden)

    Milena Díaz Molina

    2004-12-01

    Full Text Available Algunas aril-oxazolinas han sido descritas como sustancias activas sobre el sistema nervioso central, con efectos y aplicaciones diversas como depresoras, anestésicos, anticonvulsivos, etc. El presente trabajo se trazó como objetivo fundamental estudiar el posible efecto de la 2-fenil-4,4-bis (hidroximetil-2-oxazolina (OX obtenida por síntesis química bajo microondas, en 2 modelos experimentales de epilepsia: el choque electroconvulsivo por estimulación repetitiva en ratones y el de inducción de crisis convulsiva por estímulo audiogénico en el gerbo mongol. La dosis de 150 mg/kg de OX redujo el número de pulsos eléctricos necesarios para inducir la crisis tónica producida por el choque eléctrico, así como su duración. Esta misma dosis bloqueó las crisis inducidas por el estímulo audiogénico en el gerbo, y disminuyó significativamente su severidad (grados de crisis y ocurrencia. Estos resultados permiten afirmar que OX presenta un efecto antiepiléptico relacionado posiblemente con una inhibición de la sinapsis glutamatérgica en el hipocampo.Some aryl-oxazolines have been described as active substances on the central nervous system, with diverse effects and applications as depressants, anesthetics, anticonvulsants, etc. The purpose of the present paper is to study the possible effect of 2-phenyl-4,4-bis (hydroxymethyl-2-oxazoline (OX obtained by chemical synthesis under microwaves in 2 experimental models of epilepsy: the electroconvulsive shock by repetitive stimulation in mice and that of induction of convulsive seizures by audiogenic stimulus in gerbo mongol. The dose of 150 mg/kg of OX reduced the number of electric pulses, as well as its duration. This same dose blocked the seizures induced by audiogenic stimulus in gerbo and significantly reduced its severity (seizure degrees and occurrence. These reults allow to assert that OX present an antiepilectic effect possibly related to an inhibition of glutamatergic synapse in

  19. Converging cylindrical shocks in ideal magnetohydrodynamics

    KAUST Repository

    Pullin, D. I.

    2014-09-01

    We consider a cylindrically symmetrical shock converging onto an axis within the framework of ideal, compressible-gas non-dissipative magnetohydrodynamics (MHD). In cylindrical polar co-ordinates we restrict attention to either constant axial magnetic field or to the azimuthal but singular magnetic field produced by a line current on the axis. Under the constraint of zero normal magnetic field and zero tangential fluid speed at the shock, a set of restricted shock-jump conditions are obtained as functions of the shock Mach number, defined as the ratio of the local shock speed to the unique magnetohydrodynamic wave speed ahead of the shock, and also of a parameter measuring the local strength of the magnetic field. For the line current case, two approaches are explored and the results compared in detail. The first is geometrical shock-dynamics where the restricted shock-jump conditions are applied directly to the equation on the characteristic entering the shock from behind. This gives an ordinary-differential equation for the shock Mach number as a function of radius which is integrated numerically to provide profiles of the shock implosion. Also, analytic, asymptotic results are obtained for the shock trajectory at small radius. The second approach is direct numerical solution of the radially symmetric MHD equations using a shock-capturing method. For the axial magnetic field case the shock implosion is of the Guderley power-law type with exponent that is not affected by the presence of a finite magnetic field. For the axial current case, however, the presence of a tangential magnetic field ahead of the shock with strength inversely proportional to radius introduces a length scale R = √μ0/p0 I/(2π) where I is the current, μ0 is the permeability, and p0 is the pressure ahead of the shock. For shocks initiated at r ≫ R, shock convergence is first accompanied by shock strengthening as for the strictly gas-dynamic implosion. The diverging magnetic field then

  20. Shock, post-shock annealing, and post-annealing shock in ureilites

    Science.gov (United States)

    Rubin, Alan E.

    2006-01-01

    The thermal and shock histories of ureilites can be divided into four periods: 1) formation, 2) initial shock, 3) post-shock annealing, and 4) post-annealing shock. Period 1 occurred ˜4.55 Ga ago when ureilites formed by melting chondritic material. Impact events during period 2 caused silicate darkening, undulose to mosaic extinction in olivines, and the formation of diamond, lonsdaleite, and chaoite from indigenous carbonaceous material. Alkali-rich fine-grained silicates may have been introduced by impact injection into ureilites during this period. About 57% of the ureilites were unchanged after period 2. During period 3 events, impact-induced annealing caused previously mosaicized olivine grains to become aggregates of small unstrained crystals. Some ureilites experienced reduction as FeO at the edges of olivine grains reacted with C from the matrix. Annealing may also be responsible for coarsening of graphite in a few ureilites, forming euhedral-appearing, idioblastic crystals. Orthopyroxene in Meteorite Hills (MET) 78008 may have formed from pigeonite by annealing during this period. The Rb-Sr internal isochron age of ˜4.0 Ga for MET 78008 probably dates the annealing event. At this late date, impacts are the only viable heat source. About 36% of ureilites experienced period 3 events, but remained unchanged afterwards. During period 4, ˜7% of the ureilites were shocked again, as is evident in the polymict breccia, Elephant Moraine (EET) 83309. This rock contains annealed mosaicized olivine aggregates composed of small individual olivine crystals that exhibit undulose extinction. Ureilites may have formed by impact-melting chondritic material on a primitive body with heterogeneous O isotopes. Plagioclase was preferentially lost from the system due to its low impedance to shock compression. Brief melting and rapid burial minimized the escape of planetary-type noble gases from the ureilitic melts. Incomplete separation of metal from silicates during impact

  1. Resumen estudios sobre tabaquismo

    OpenAIRE

    Gónzalez, M.M. (M.)

    2009-01-01

    Este documento se realizó para publicar en la página Web de la Gerencia de Atención primaria del Área III. Este documento es una recopilación de estudios sobre tabaquismo. Gerencia de Atención Primaria Área III

  2. Multimedia sobre mantenimiento industrial

    National Research Council Canada - National Science Library

    2012-01-01

    ..., entre otras facilidades. Puntualizado, el mantenimiento industrial es una actividad que conserva la calidad del servicio que se presta, y sobre todo en la infraestructura existente en los centros de produccion con optimas condiciones de seguridad, eficiencia y economia. El mantenimiento es de gran importancia, pues sus objetivos son la base para un adecuado f...

  3. Attenuation of Shock Waves using Perforated Plates

    Science.gov (United States)

    Pavan Kumar, CH V. L. C. S.; Hitesh Reddy, C.; Rahul Sai, L.; Dharani Kumar, K. S. S.; Nagaraja, S. R.

    2017-08-01

    The shock/blast waves generated due to explosions cause wide spread damage to the objects in its path. Different techniques have been used to attenuate shock wave over pressure, to reduce the catastrophic effects. Perforated plates can be used effectively to attenuate the shock wave pressure. In this paper shock wave interaction with perforated plates is simulated using COMSOL multiphysics software. The pressure drop varied from 43.75% to 26% for porosity varying from 10% to 40.

  4. Entropy jump across an inviscid shock wave

    Science.gov (United States)

    Salas, Manuel D.; Iollo, Angelo

    1995-01-01

    The shock jump conditions for the Euler equations in their primitive form are derived by using generalized functions. The shock profiles for specific volume, speed, and pressure are shown to be the same, however density has a different shock profile. Careful study of the equations that govern the entropy shows that the inviscid entropy profile has a local maximum within the shock layer. We demonstrate that because of this phenomenon, the entropy, propagation equation cannot be used as a conservation law.

  5. Suppressive and Facilitative Effects of Shock Intensity and Interresponse Times Followed by Shock

    Science.gov (United States)

    Everly, Jessica B.; Perone, Michael

    2012-01-01

    Although response-dependent shock often suppresses responding, response facilitation can occur. In two experiments, we examined the suppressive and facilitative effects of shock by manipulating shock intensity and the interresponse times that produced shock. Rats' lever presses were reinforced on a variable-interval 40-s schedule of food…

  6. Shock Safe Nepal: team one

    NARCIS (Netherlands)

    Oosterhof, A.J.; Düzgün, B.C.; Spelt, C.J.; De Stoppelaar, A.O.; Van Wijnbergen, E.C.M.

    2016-01-01

    As a response to the 2015 Nepal earthquakes Shock Safe Nepal was founded to function as platform intended to contribute to the development of knowledge on earthquake safe housing. The project started on initiative of the Consul General of Nepal to The Netherlands Cas de Stoppelaar and the faculty of

  7. Nonparametric Regression with Common Shocks

    National Research Council Canada - National Science Library

    Souza-Rodrigues, Eduardo

    2016-01-01

    .... By appealing to disintegration theory, I provide sufficient conditions for the existence of such conditional densities and show that the estimator converges in probability to the Kolmogorov conditional expectation given the sigma-field generated by the common shocks. I also establish the rate of convergence and the asymptotic distribution of the kernel estimator.

  8. Eight Annual Conference on Shock

    Science.gov (United States)

    1985-11-01

    FOUR PHASES OF HEMORRHAGIC SHOCK. F.J. Pearce, R.J. Connett and W.R. Drucker. University of Rochester School of Medicine and Dentistry , Rochester, NY...BROCK-UIM, D. WELLS, A. ZANiITI, J.W. DNING. Departments of Physiology, Paediatric Surgery and Anaesthetics University of Natal Iedical School, Durban

  9. Model for Shock Wave Chaos

    KAUST Repository

    Kasimov, Aslan R.

    2013-03-08

    We propose the following model equation, ut+1/2(u2−uus)x=f(x,us) that predicts chaotic shock waves, similar to those in detonations in chemically reacting mixtures. The equation is given on the half line, x<0, and the shock is located at x=0 for any t≥0. Here, us(t) is the shock state and the source term f is taken to mimic the chemical energy release in detonations. This equation retains the essential physics needed to reproduce many properties of detonations in gaseous reactive mixtures: steady traveling wave solutions, instability of such solutions, and the onset of chaos. Our model is the first (to our knowledge) to describe chaos in shock waves by a scalar first-order partial differential equation. The chaos arises in the equation thanks to an interplay between the nonlinearity of the inviscid Burgers equation and a novel forcing term that is nonlocal in nature and has deep physical roots in reactive Euler equations.

  10. endotoxin induced shock in sheep

    African Journals Online (AJOL)

    Abstract: Physiological changes associated with septic shock are due to an interplay of a number of inflammatory mediators which increase capillary permeability and vasodilation leading to circulatory disturbance. Research evidence shows that sepsis-associated vascular relaxation is mediated by nitric oxide. Nitric oxide ...

  11. Nonlinearity, Conservation Law and Shocks

    Indian Academy of Sciences (India)

    Nonlinearity, Conservation Law and Shocks. Part I : Genuine Nonlinearity and Discontinuous Solutions. Phoolan Prasad is with the. Department of. Mathematics, Indian. Institute of Science and has been working in the area of nonlinear waves and hyperbolic partial differential equations. He is deeply interested in.

  12. Nonlinearity, Conservation Law and Shocks

    Indian Academy of Sciences (India)

    Nonlinearity, Conservation Law and Shocks. 2. Stability Consideration and Examples. Phoolan Prasad is with the. Department of. Mathematics, Indian. Institute of Science and has been working in the area of nonlinear waves and hyperbolic partial differential equations. He is deeply interested in mathematics education at.

  13. Shock wave treatment in medicine

    Indian Academy of Sciences (India)

    Unknown

    for the lung, brain, abdomen and other organs is part of the investigation in this program. The best transition media for the shock wave is water and gelatin because of the similarity in the acoustic impedance to the tissue. These investigations and cooperation with physicians lead to the idea to disintegrate kidney stones with ...

  14. Building your own shock tube

    NARCIS (Netherlands)

    J. Naber (Jorick)

    2005-01-01

    textabstractThis report treats the development of a shock tube solver for the simulation of flows described by the one-dimensional Euler equations. A well-known one-dimensional flow problem is the initial Riemann problem, which treats the development of a flow due to two initially separated

  15. Early Treatment in Shock. Addendum

    Science.gov (United States)

    2012-08-01

    Van Way, CW III. Use of Nutrients in Resuscitation from Shock. FELANPE, Federation Latinoamericana de Terapia Nutricional, Nutrition Clinica, y...water and 1.0 mL hexane containing 50 mg/L butylated hydroxytoluene (BHT, an antioxidant; Sigma) were added. Following manual shaking for 30 sec- onds

  16. Magnetic Fields inside Extremely Fast Shock Waves

    NARCIS (Netherlands)

    Wiersma, J.

    2007-01-01

    The aim of my research on magnetic fields in extremely fast shock waves has been to predict the properties of shock waves that move almost with the speed of light. These shocks are created in the tenuous interstellar medium by catastrophic events such as the explosion of stars many times

  17. 33 CFR 159.105 - Shock test.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Shock test. 159.105 Section 159... MARINE SANITATION DEVICES Design, Construction, and Testing § 159.105 Shock test. The device, with liquid... shocks that are ten times the force of gravity (10g) and have a duration of 20-25 milliseconds measured...

  18. Percutaneous mechanical circulatory support in cardiogenic shock

    NARCIS (Netherlands)

    Ouweneel, D.M.

    2017-01-01

    Cardiogenic shock is the most common cause of death in patients with acute myocardial infarction. Around 10% of the patients with an ST-segment elevation myocardial infarction develop cardiogenic shock. Mortality in cardiogenic shock has been reduced over the last few decades, but it still remains

  19. 33 CFR 183.584 - Shock test.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Shock test. 183.584 Section 183... SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Tests § 183.584 Shock test. A fuel tank is tested by... surface of the tank. The duration of each vertical acceleration pulse is measured at the base of the shock...

  20. Coping with shocks in rural Ethiopia

    NARCIS (Netherlands)

    Z.Y. Debebe (Zelalem); A.D. Mebratie (Anagaw); R.A. Sparrow (Robert); D. Abebaw Ejigie (Degnet); M. Dekker (Marleen); G. Alemu (Getnet ); A.S. Bedi (Arjun Singh)

    2013-01-01

    textabstractBased on household survey data and event history interviews undertaken in a highly shock prone country, this paper investigates which shocks trigger which coping responses and why? We find clear differences in terms of coping strategies across shock types. The two relatively covariate

  1. Streptococcus pyogenes toxic-shock syndrome

    OpenAIRE

    Antunes, R.; Diogo, M; Carvalho, A.; Pimentel, T; Oliveira, J.

    2011-01-01

    Recently there has been an exponential increase in invasive infections caused by Streptococcus ß hemolyticcus group A. In about one third of cases they are complicated by toxic shock syndrome, characterized by septic shock and multiorgan failure. The authors, by their rarity, report a case of bacteraemia caused by Streptococcus pyogenes complicated by toxic shock syndrome.

  2. Propagation of a compression shock wave in He II induced by shock impingement

    OpenAIRE

    村上, 正秀; 上田, 康裕; 谷中, 一喜; 永井, 大樹; Masahide, MURAKAMI; Yasuhiro, UETA; Kazuyoshi, YANAKA; Hiroki, NAGAI; Hung Suk, YANG; 筑波大; Institute of Engineering Mechanics and Systems, University of Tsukuba

    2001-01-01

    The propagation of a compression shock wave in superfluid helium (He II) was experimentally investigated by using the superfluid shock tube facility. A shock wave is generated in He II by the impingement of a gas dynamic shock wave onto vapor-He II interface. In fact, upon the impingement two modes of shock waves, a compression and a thermal shock waves, are induced in He II. Here, we are only interested in the former. One of our research target is the shock-compressed phase transition (He II...

  3. Explicando el paleoamericano y su probable extinción, a través de inferencias comparativas y experimentales

    Directory of Open Access Journals (Sweden)

    Héctor M. Pucciarelli

    2009-07-01

    Full Text Available Sobre la base de estudios previos, se inició una búsqueda puntual de muestras conteniendo presuntos paleoamericanos y amerindios intramuestrales que en proporciones variables se descubrieron en la base craneofuncional América 12.sys . Se trabajó con 49 muestras, ordenadas de a siete muestras por grupo, en siete grupos con contenido paulatinamente decreciente en la proporción de paleoamericanos. El objeto fue lograr un modelo que simule un efecto migración-reemplazo, en el que los paleoamericanos deberían disminuir paulatinamente en función del incremento de los amerindios. Una proporción cercana a cero al final de la prueba sugeriría la presencia del efecto buscado, esto es, el reemplazo total de los paleoamericanos por los amerindios. Sólo las dos primeras muestras del grupo I contuvieron el 100% de paleoamericanos (pericues y algonquinos, mientras que las cinco restantes del mismo grupo, fueron Lagoa Santa, Lauricocha, Aguazuque, Checua y Tequendama-Mosquera. Todas ellas con proporciones variables de componente amerindio. Fue obtenido que: a los paleoamericanos integraban al principio del experimento el 100% de las muestras estudiadas; mientras que hacia el final del proceso quedaron reducidos a menos del 3%; b este proceso no fue brusco sino paulatino y se hizo efectivo a lo largo de las siete etapas que demandó la simulación, a fin de llegar a un valor cercano a cien (97,6% de saturación amerindia, lo cual implica ser causa probable —según propone el modelo— de la posible extinción de los paleoamericanos por saturación poblacional del componente amerindio.

  4. Evolución y nuevos retos de la didáctica de las ciencias experimentales

    Directory of Open Access Journals (Sweden)

    2012-01-01

    Full Text Available Este estudio presenta una revisión de los contenidos para la enseñanza de la llamada "naturaleza de la ciencia" (y tecnología desde las diversas aportaciones de la investigación didáctica especializada sobre estas cuestiones. La visión que se presenta aquí está relacionada con y es dependiente de diversos conceptos modernos, tales como la situación de profunda interacción entre ciencia y tecnología en la actividad científica actual (tecnociencia, que se traduce en una visión de la educación científica donde también se integra la tecnología; el lema de la alfabetización científica y tecnológica para todos, como guía general para lograr educar la competencia científica de los estudiantes; y la naturaleza de la ciencia (y tecnología como componente innovador de la alfabetización para todos. La revisión presenta las diversas propuestas de contenidos básicos para la enseñanza de la naturaleza de la ciencia (y tecnología que se manejan usualmente en la literatura especializada, con el fin de iluminar la selección de los contenidos curriculares y contextualizar mejor las propuestas del currículo español de ciencias (que se abordará en la segunda parte de este estudio. El objetivo es ayudar al profesorado a clarificar los contenidos enseñables y aportar sentido a los nuevos contenidos en los currículos españoles de ciencias acerca de estas complejas cuestiones.

  5. Pastas de relleno para reintegración volumétrica de esculturas en cera. Primeros resultados experimentales

    Directory of Open Access Journals (Sweden)

    Nerea del Moral Azanza

    2014-12-01

    Full Text Available La conservación de esculturas en cera supone un gran reto para el restaurador al tratarse de un material que presenta diversas dificultades derivadas tanto de sus propiedades físicas como de sus procesos de envejecimiento natural. Con el tiempo, los propios materiales adicionados a la cera para la preparación de las pastas de modelar sufren transformaciones químicas que ocasionan un aumento de la fragilidad en este tipo de objetos. Este hecho unido a la acción de agentes de degradación externos, sobre todo cambios bruscos de temperatura, en el ambiente expositivo puede conllevar la formación de micro-fisuras y grietas, y en grado extremo la existencia de fracturas y pérdidas del material, haciendo necesario efectuar tratamientos de reintegración en las zonas dañadas. Este trabajo muestra los primeros resultados obtenidos tras someter a estudio ciertas características físicas de la cera, a fin de desarrollar un método científico de intervención en lagunas. Se ha partido de ocho posibles pastas de relleno para analizar sus intervalos de fusión y su comportamiento tras ser sometidas a envejecimiento artificial, con el objetivo de encontrar una pasta idónea para la restauración de los modelos anatómicos en cera de la colección Javier Puerta de la Universidad Complutense de Madrid. Los resultados que se exponen podrían ser aplicables a otras colecciones de ceroplástica y/o artefactos en cera.

  6. Interplanetary Shocks Lacking Type 2 Radio Bursts

    Science.gov (United States)

    Gopalswamy, N.; Xie, H.; Maekela, P.; Akiyama, S.; Yashiro, S.; Kaiser, M. L.; Howard, R. A.; Bougeret, J.-L.

    2010-01-01

    We report on the radio-emission characteristics of 222 interplanetary (IP) shocks detected by spacecraft at Sun-Earth L1 during solar cycle 23 (1996 to 2006, inclusive). A surprisingly large fraction of the IP shocks (approximately 34%) was radio quiet (RQ; i.e., the shocks lacked type II radio bursts). We examined the properties of coronal mass ejections (CMEs) and soft X-ray flares associated with such RQ shocks and compared them with those of the radio-loud (RL) shocks. The CMEs associated with the RQ shocks were generally slow (average speed approximately 535 km/s) and only approximately 40% of the CMEs were halos. The corresponding numbers for CMEs associated with RL shocks were 1237 km/s and 72%, respectively. Thus, the CME kinetic energy seems to be the deciding factor in the radio-emission properties of shocks. The lower kinetic energy of CMEs associated with RQ shocks is also suggested by the lower peak soft X-ray flux of the associated flares (C3.4 versus M4.7 for RL shocks). CMEs associated with RQ CMEs were generally accelerating within the coronagraph field of view (average acceleration approximately +6.8 m/s (exp 2)), while those associated with RL shocks were decelerating (average acceleration approximately 3.5 m/s (exp 2)). This suggests that many of the RQ shocks formed at large distances from the Sun, typically beyond 10 Rs, consistent with the absence of metric and decameter-hectometric (DH) type II radio bursts. A small fraction of RL shocks had type II radio emission solely in the kilometric (km) wavelength domain. Interestingly, the kinematics of the CMEs associated with the km type II bursts is similar to those of RQ shocks, except that the former are slightly more energetic. Comparison of the shock Mach numbers at 1 AU shows that the RQ shocks are mostly subcritical, suggesting that they were not efficient in accelerating electrons. The Mach number values also indicate that most of these are quasi-perpendicular shocks. The radio-quietness is

  7. Culture shock: Improving software quality

    Energy Technology Data Exchange (ETDEWEB)

    de Jong, K.; Trauth, S.L.

    1988-01-01

    The concept of software quality can represent a significant shock to an individual who has been developing software for many years and who believes he or she has been doing a high quality job. The very idea that software includes lines of code and associated documentation is foreign and difficult to grasp, at best. Implementation of a software quality program hinges on the concept that software is a product whose quality needs improving. When this idea is introduced into a technical community that is largely ''self-taught'' and has been producing ''good'' software for some time, a fundamental understanding of the concepts associated with software is often weak. Software developers can react as if to say, ''What are you talking about. What do you mean I'm not doing a good job. I haven't gotten any complaints about my code yetexclamation'' Coupling such surprise and resentment with the shock that software really is a product and software quality concepts do exist, can fuel the volatility of these emotions. In this paper, we demonstrate that the concept of software quality can indeed pose a culture shock to developers. We also show that a ''typical'' quality assurance approach, that of imposing a standard and providing inspectors and auditors to assure its adherence, contributes to this shock and detracts from the very goal the approach should achieve. We offer an alternative, adopted through experience, to implement a software quality program: cooperative assistance. We show how cooperation, education, consultation and friendly assistance can overcome this culture shock. 3 refs.

  8. Generation and evolution of interplanetary slow shocks

    Directory of Open Access Journals (Sweden)

    C.-C. Wu

    Full Text Available It is well known that most MHD shocks observed within 1 AU are MHD fast shocks. Only a very limited number of MHD slow shocks are observed within 1 AU. In order to understand why there are only a few MHD slow shocks observed within 1 AU, we use a one-dimensional, time-dependent MHD code with an adaptive grid to study the generation and evolution of interplanetary slow shocks (ISS in the solar wind. Results show that a negative, nearly square-wave perturbation will generate a pair of slow shocks (a forward and a reverse slow shock. In addition, the forward and the reverse slow shocks can pass through each other without destroying their characteristics, but the propagating speeds for both shocks are decreased. A positive, square-wave perturbation will generate both slow and fast shocks. When a forward slow shock (FSS propagates behind a forward fast shock (FFS, the former experiences a decreasing Mach number. In addition, the FSS always disappears within a distance of 150R (where R is one solar radius from the Sun when there is a forward fast shock (with Mach number ≥1.7 propagating in front of the FSS. In all tests that we have performed, we have not discovered that the FSS (or reverse slow shock evolves into a FFS (or reverse fast shock. Thus, we do not confirm the FSS-FFS evolution as suggested by Whang (1987.

  9. The microphysics of collisionless shock waves.

    Science.gov (United States)

    Marcowith, A; Bret, A; Bykov, A; Dieckman, M E; Drury, L O'C; Lembège, B; Lemoine, M; Morlino, G; Murphy, G; Pelletier, G; Plotnikov, I; Reville, B; Riquelme, M; Sironi, L; Novo, A Stockem

    2016-04-01

    Collisionless shocks, that is shocks mediated by electromagnetic processes, are customary in space physics and in astrophysics. They are to be found in a great variety of objects and environments: magnetospheric and heliospheric shocks, supernova remnants, pulsar winds and their nebulæ, active galactic nuclei, gamma-ray bursts and clusters of galaxies shock waves. Collisionless shock microphysics enters at different stages of shock formation, shock dynamics and particle energization and/or acceleration. It turns out that the shock phenomenon is a multi-scale non-linear problem in time and space. It is complexified by the impact due to high-energy cosmic rays in astrophysical environments. This review adresses the physics of shock formation, shock dynamics and particle acceleration based on a close examination of available multi-wavelength or in situ observations, analytical and numerical developments. A particular emphasis is made on the different instabilities triggered during the shock formation and in association with particle acceleration processes with regards to the properties of the background upstream medium. It appears that among the most important parameters the background magnetic field through the magnetization and its obliquity is the dominant one. The shock velocity that can reach relativistic speeds has also a strong impact over the development of the micro-instabilities and the fate of particle acceleration. Recent developments of laboratory shock experiments has started to bring some new insights in the physics of space plasma and astrophysical shock waves. A special section is dedicated to new laser plasma experiments probing shock physics.

  10. Contacto normal entre un medio elasto-plástico continuo y una esfera rígida : observaciones experimentales y computacionales

    Directory of Open Access Journals (Sweden)

    Ángela María Pedraza

    2005-01-01

    Full Text Available Se presenta en este trabajo una investigación experimental y numérica del contacto normal de una esfera rígida con una placa plana de material cuyo comportamiento mecánico se asume de tipo elasto-plástico. Los esfuerzos locales bajo el punto de contacto se han obtenido experimentalmente mediante visualización foto-elástica. Se ha evaluado numéricamente la evolución de los bulbos de esfuerzo bajo el punto contacto como función del tiempo y se ha efectuado la comparación con las observaciones experimentales. Los resultados indican que un modelo elasto-plástico tridimensional reproduce de manera apropiada las características principales observadas en los experimentos físicos. Este ejercicio puramente académico y de carácter didáctico enfatiza en el enorme potencial de los elementos finitos en la solución de problemas de deformación bajo diferentes tipos de modelos constitutivos y pone de manifiesto la enorme utilidad del modelamiento matemático y computacional basado en aproximaciones continuas de la materia

  11. Toxic shock syndrome responsive to steroids

    Directory of Open Access Journals (Sweden)

    Vergis Nikhil

    2007-02-01

    Full Text Available Abstract Background Toxic Shock Syndrome is a dangerous disease with clinical features mimicking bacterial sepsis. The best management of Toxic Shock Syndrome is not determined. Case presentation A 28 year-old woman presenting with high fever, tachycardia and widespread erythroderma is described. She failed to respond to intravenous antibiotics and required ITU admission. High dose corticosteroids dramatically improved her clinical condition. Conclusion Toxic Shock Syndrome should be considered in the differential diagnosis of unexplained fever, rash and features resembling septic shock. Corticosteroids should be considered in the treatment of Toxic Shock Syndrome.

  12. Hybrid Simulations of Particle Acceleration at Shocks

    Energy Technology Data Exchange (ETDEWEB)

    Caprioli, Damiano

    2014-11-15

    We present the results of large hybrid (kinetic ions – fluid electrons) simulations of particle acceleration at non-relativistic collisionless shocks. Ion acceleration efficiency and magnetic field amplification are investigated in detail as a function of shock inclination and strength, and compared with predictions of diffusive shock acceleration theory, for shocks with Mach number up to 100. Moreover, we discuss the relative importance of resonant and Bell's instability in the shock precursor, and show that diffusion in the self-generated turbulence can be effectively parametrized as Bohm diffusion in the amplified magnetic field.

  13. Post-Shock Sampling of Shock-Heated Hydrocarbon Fuels

    Science.gov (United States)

    2016-07-07

    12211 Research Triangle Park, NC 27709-2211 Gas sampling, shock tube, jet fuel, gas chromatography REPORT DOCUMENTATION PAGE 11. SPONSOR/MONITOR’S... studies in science, mathematics, engineering or technology fields: Student Metrics This section only applies to graduating undergraduates supported by this...addition of an extractive, sampling- based measurement technique allows for the measurement of species not yet measureable by optical methods (e.g. H2

  14. Escrito sobre el cuerpo

    Directory of Open Access Journals (Sweden)

    Antonio Malalana Ureña

    2013-09-01

    Full Text Available El catálogo, en una edición bilingüe español-inglés, es una pequeña guía de la exposición Shirin Neshat. Escrito sobre el cuerpo, muestra que se integra dentro de los actos de PHOTOESPAÑA13, el festival internacional de fotografía y artes visuales. El esquema del libro es sencillo y los textos son extremadamente divulgativos. El primero de ellos, Escrito sobre el cuerpo (pp. 10-15, cuyo autor es Octavio Zaya, comisario de la exposición, resume la trayectoria de esta intelectual, que "interactúa" con la fotografía y los formatos audiovisuales, y nos presenta la argumentación narrativa de los documentos expuestos, contextualizando la obra recopilada.

  15. Tesis sobre municipalismo libertario

    OpenAIRE

    Bookchin, Murray

    2014-01-01

    Históricamente, la teoría y la práctica social radical se han centrado sobre dos campos de la actividad social humana: el lugar de trabajo y la comunidad. A partir de la creación del Estado-nación y de la Revolución Industrial, la economía ha ido adquiriendo una posición predominante sobre la comunidad; y no sólo en la ideología capitalista, sino también en los diferentes socialismos, libertarios y autoritarios, que han ido apareciendo en el último siglo. Este cambio de posición del socialism...

  16. Initial conditions of radiative shock experimentsa)

    Science.gov (United States)

    Kuranz, C. C.; Drake, R. P.; Krauland, C. M.; Marion, D. C.; Grosskopf, M. J.; Rutter, E.; Torralva, B.; Holloway, J. P.; Bingham, D.; Goh, J.; Boehly, T. R.; Sorce, A. T.

    2013-05-01

    We performed experiments at the Omega Laser Facility to characterize the initial, laser-driven state of a radiative shock experiment. These experiments aimed to measure the shock breakout time from a thin, laser-irradiated Be disk. The data are then used to inform a range of valid model parameters, such as electron flux limiter and polytropic γ, used when simulating radiative shock experiments using radiation hydrodynamics codes. The characterization experiment and the radiative shock experiment use a laser irradiance of ˜7 × 1014 W cm-2 to launch a shock in the Be disk. A velocity interferometer and a streaked optical pyrometer were used to infer the amount of time for the shock to move through the Be disk. The experimental results were compared with simulation results from the Hyades code, which can be used to model the initial conditions of a radiative shock system using the CRASH code.

  17. Initial conditions of radiative shock experiments

    Energy Technology Data Exchange (ETDEWEB)

    Kuranz, C. C.; Drake, R. P.; Krauland, C. M.; Marion, D. C.; Grosskopf, M. J.; Rutter, E.; Torralva, B.; Holloway, J. P. [Department of Atmospheric, Oceanic and Space Science, University of Michigan, Center for Radiative Shock Hydrodynamics, 2455 Hayward Dr., Ann Arbor, Michigan 48109 (United States); Bingham, D.; Goh, J. [Department of Statistics and Actuarial Science, Simon Fraser University, Burnaby, BC, Canada V5A 1S6 (Canada); Boehly, T. R.; Sorce, A. T. [Laboratory for Laser Energetics, University of Rochester, New York 14623 (United States)

    2013-05-15

    We performed experiments at the Omega Laser Facility to characterize the initial, laser-driven state of a radiative shock experiment. These experiments aimed to measure the shock breakout time from a thin, laser-irradiated Be disk. The data are then used to inform a range of valid model parameters, such as electron flux limiter and polytropic γ, used when simulating radiative shock experiments using radiation hydrodynamics codes. The characterization experiment and the radiative shock experiment use a laser irradiance of ∼7 × 10{sup 14} W cm{sup −2} to launch a shock in the Be disk. A velocity interferometer and a streaked optical pyrometer were used to infer the amount of time for the shock to move through the Be disk. The experimental results were compared with simulation results from the Hyades code, which can be used to model the initial conditions of a radiative shock system using the CRASH code.

  18. Shock Wave Dynamics in Weakly Ionized Plasmas

    Science.gov (United States)

    Johnson, Joseph A., III

    1999-01-01

    An investigation of the dynamics of shock waves in weakly ionized argon plasmas has been performed using a pressure ruptured shock tube. The velocity of the shock is observed to increase when the shock traverses the plasma. The observed increases cannot be accounted for by thermal effects alone. Possible mechanisms that could explain the anomalous behavior include a vibrational/translational relaxation in the nonequilibrium plasma, electron diffusion across the shock front resulting from high electron mobility, and the propagation of ion-acoustic waves generated at the shock front. Using a turbulence model based on reduced kinetic theory, analysis of the observed results suggest a role for turbulence in anomalous shock dynamics in weakly ionized media and plasma-induced hypersonic drag reduction.

  19. Shock-induced chemistry in organic materials

    Energy Technology Data Exchange (ETDEWEB)

    Dattelbaum, Dana M [Los Alamos National Laboratory; Sheffield, Steve [Los Alamos National Laboratory; Engelke, Ray [Los Alamos National Laboratory; Manner, Virginia [Los Alamos National Laboratory; Chellappa, Raja [Los Alamos National Laboratory; Yoo, Choong - Shik [WASHINGTON STATE UNIV

    2011-01-20

    The combined 'extreme' environments of high pressure, temperature, and strain rates, encountered under shock loading, offer enormous potential for the discovery of new paradigms in chemical reactivity not possible under more benign conditions. All organic materials are expected to react under these conditions, yet we currently understand very little about the first bond-breaking steps behind the shock front, such as in the shock initiation of explosives, or shock-induced reactivity of other relevant materials. Here, I will present recent experimental results of shock-induced chemistry in a variety of organic materials under sustained shock conditions. A comparison between the reactivity of different structures is given, and a perspective on the kinetics of reaction completion under shock drives.

  20. Experimental methods of shock wave research

    CERN Document Server

    Seiler, Friedrich

    2016-01-01

    This comprehensive and carefully edited volume presents a variety of experimental methods used in Shock Waves research. In 14 self contained chapters this 9th volume of the “Shock Wave Science and Technology Reference Library” presents the experimental methods used in Shock Tubes, Shock Tunnels and Expansion Tubes facilities. Also described is their set-up and operation. The uses of an arc heated wind tunnel and a gun tunnel are also contained in this volume. Whenever possible, in addition to the technical description some typical scientific results obtained using such facilities are described. Additionally, this authoritative book includes techniques for measuring physical properties of blast waves and laser generated shock waves. Information about active shock wave laboratories at different locations around the world that are not described in the chapters herein is given in the Appendix, making this book useful for every researcher involved in shock/blast wave phenomena.

  1. Carta sobre una estampilla

    Directory of Open Access Journals (Sweden)

    Luis Navarro

    1962-05-01

    Full Text Available Queridos compañeros colombianos del arte: la última carta que me llega de vuestro país me ha impresionado de forma inesperada tan solo con caer en mis manos, sin rasgar el sobre ni tener tiempo de conocer el remitente. Es una carta como cualquier otra: señor Fulano de Tal, calle cual, Madrid, España.

  2. Cures for the Expansion Shock and the Shock Instability of the Roe Scheme

    CERN Document Server

    Li, Xue-song; Gu, Chun-wei

    2016-01-01

    A common defect of the Roe scheme is the production of non-physical expansion shock and shock instability. An improved method with several advantages was presented to suppress the shock instability. However, this method cannot prevent expansion shock and is incompatible with the traditional curing method for expansion shock. Therefore, the traditional curing mechanism is analyzed. The discussion explains the effectiveness of the traditional curing method and identifies several defects, one of which leads to incompatibility between curing the shock instability and expansion shock. Consequently, a new improved Roe scheme is proposed in this study. This scheme is concise, easy to implement, low computational cost, and robust. More importantly, the scheme can simultaneously cure the shock instability and expansion shock without additional costs.

  3. Insight into magnetorheological shock absorbers

    CERN Document Server

    Gołdasz, Janusz

    2015-01-01

    This book deals with magnetorheological fluid theory, modeling and applications of automotive magnetorheological dampers. On the theoretical side a review of MR fluid compositions and key factors affecting the characteristics of these fluids is followed by a description of existing applications in the area of vibration isolation and flow-mode shock absorbers in particular. As a majority of existing magnetorheological devices operates in a so-called flow mode a critical review is carried out in that regard. Specifically, the authors highlight common configurations of flow-mode magnetorheological shock absorbers, or so-called MR dampers that have been considered by the automotive industry for controlled chassis applications. The authors focus on single-tube dampers utilizing a piston assembly with one coil or multiple coils and at least one annular flow channel in the piston.

  4. Shock Properties of Fansteel85

    Energy Technology Data Exchange (ETDEWEB)

    Erskine, D J; Nellis, W J

    2008-08-22

    The shock response of Fansteel85 was investigated in the pressure range 10-90 GPa. The linear U{sub s}-U{sub p} coefficients were found to be C = 4.160 {+-} .015 km/s and S = 1.195 {+-} .015. Ultrasound measurements yielded C{sub L} = 4.827 and C{sub T} = 2.101, implying a bulk sound speed C{sub B} = 4.173, which is in excellent agreement with the measured value for C. The Hugoniot elastic limit was determined to be 3.11 {+-} .05 GPa at U{sub p} = .0595 {+-} .001 km/s and U{sub s} = 4.886 {+-} .01 km/s. The speed of sound in the material behind the shock front was determined to be 5.10 {+-} .06 km/s at 10.2 GPa and 5.25 {+-} .06 km/s at 20.6 GPa.

  5. Toxic Shock Syndrome following Tattooing

    Directory of Open Access Journals (Sweden)

    Ki Young Jeong

    2015-08-01

    Full Text Available Toxic shock syndrome (TSS is a rare but life-threatening illness that is mainly caused by toxigenic strains of Staphylococcus aureus. Although TSS is classically known to be associated with tampon use, the number of TSS cases with non-menstrual causes such as skin and soft tissue infection has been increasing. Tattooing can result in several complications such as localized and systemic infections, inflammatory skin eruptions and neoplasms. We recently experienced a 26-year-old man diagnosed with typical TSS following tattooing. He complained of fever, chills and erythematous rash at tattoo site. Subsequently, the patient developed sign of shock. The skin cultures on the tattoo site were positive for methicillin-sensitive Staphylococcus aureus. The patient was successfully treated with vasopressor infusion and intravenous antibiotics and was discharged without complications. On discharge from the hospital 7 days later, desquamations on the tattoo site, fingers and toes were observed.

  6. Dissipative Shocks behind Bacteria Gliding

    CERN Document Server

    Virga, Epifanio G

    2014-01-01

    Gliding is a means of locomotion on rigid substrates utilized by a number of bacteria includingmyxobacteria and cyanobacteria. One of the hypotheses advanced to explain this motility mechanism hinges on the role played by the slime filaments continuously extruded from gliding bacteria. This paper solves in full a non-linear mechanical theory that treats as dissipative shocks both the point where the extruded slime filament comes in contact with the substrate, called the filament's foot, and the pore on the bacterium outer surface from where the filament is ejected. We prove that kinematic compatibility for shock propagation requires that the bacterium uniform gliding velocity (relative to the substrate) and the slime ejecting velocity (relative to the bacterium) must be equal, a coincidence that seems to have already been observed.

  7. ENTENDIMIENTO CONCEPTUAL DE ESTUDIANTES UNIVERSITARIOS SOBRE

    Directory of Open Access Journals (Sweden)

    Roberto Figueroa Molina

    2010-11-01

    Full Text Available El propósito de esta investigación fue estudiar el entendimiento conceptual de los estudiantes universitarios de ciencias naturales de la Universidad del Atlántico, mediante la implementación de la estrategia (ECA: exploración, conceptualización y aplicación, y la utilización de medidas repetidas obtenidas a partir de los mapas conceptuales acercade los conceptos en las ciencias experimentales.

  8. Shock compression of precompressed deuterium

    Science.gov (United States)

    Armstrong, Michael; Crowhurst, Jonathan; Goncharov, Alexander; Zaug, Joseph; Bastea, Sorin; Militzer, Burkhard

    2012-03-01

    Here we report quasi-isentropic dynamic compression and thermodynamic characterization of solid, precompressed deuterium over an ultra fast time scale (< 100 ps) and a microscopic length scale (< 1 ìm). We further report a fast transition in dynamically compressed solid deuterium that is consistent with the ramp to shock transition, with a time scale of less than 10 ps. These results suggest that high density dynamic compression of hydrogen may be possible on microscopic length scales.

  9. Análisis de evidencia de las investigaciones sobre conciencia y lenguaje 2000-2010: una revisión sistemática

    Directory of Open Access Journals (Sweden)

    Johny Villada Zapata

    2012-01-01

    Full Text Available Debido a la importancia de la teorización de la conciencia y el lenguaje, este estudio retomó 86 artículos académicos sobre estos procesos publicados entre 2000 y 2010. Para el análisis de los artículos se utilizó la clasificación hecha por The Scottish Intercollegiate Guidelines Network (SIGN, que permite identificar el nivel de evidencia y los grados de recomendación de los mismos. La mayoría de las investigaciones alcanzan un nivel descriptivo-correlacional, y se encontraron pocos estudios explicativos. En los estudios sobre el lenguaje,el diseño metodológico es recurrentemente transversal, mientras que los diseños experimentales aparecen con mayor frecuencia en las investigaciones sobre la conciencia. Los artículos sobre la conciencia tienen un nivel mayor de evidencia y grados de recomendación que los del lenguaje, asunto que pone de manifiesto el interés creciente por el estudio de este proceso.

  10. Estadísticos poblacionales de Triatoma sordida Stäl 1859 (Hemiptera : Reduviidae en condiciones experimentales Population statistics of Triatoma sordida Stäl 1859 (Hemiptera: Reduviidae in experimental conditions

    Directory of Open Access Journals (Sweden)

    Elena B. Oscherov

    1996-10-01

    Full Text Available Se realizó el seguimiento longitudinal de cuatro cohortes de 100 huevos cada una. Los insectos fueron criados a 28°C ± 3°C y 63 % ± 10% de humedad relativa, y alimentados cada siete días sobre gallina (Gallus domesticus, durante 40 min. Las cohortes fueron controladas una vez por semana. Se observó un valor constante de supervivencia en las cuatro cohortes, sin picos importantes. La expectativa de vida de los machos, en promedio, fue de 37,4 semanas y la de las hembras 36,8. El tiempo generacional demandó 61,7 semanas. La tasa reproductiva neta indica que esta población se incrementará 143,3 veces con cada generación. La tasa intrínseca de crecimiento natural fue de 0,082 por semana. El máximo valor reproductivo se verificó, en promedio, a la tercer semana del ingreso al estado adulto. La distribución estable de edades de T. sordida sería de 32% huevos, 26% ninfas de primer estadio, 19% ninfas de segundo estadio, 13% ninfas de tercer estadio, 6% ninfas de cuarto estadio, 3% ninfas de quinto estadio y 1% de adultos. Es la primera cita para Argentina sobre la tabla de vida de T. sordida. El análisis de estos parámetros permite considerar que esta especie se comporta como "K estratega", en condiciones experimentales.Foram estudados diferentes parâmetros populacionais de Triatoma sordida em condições de laboratório. Realizou-se um seguimento longitudinal de quatro coortes de 100 ovos cada uma; os insetos foram criados a 28°C ± 3°C e 63% ± 10% de umidade relativa, e alimentados cada sete dias sobre galinha (Gallus domesticus durante 40'. As coortes foram controladas uma vez por semana. A expectativa de vida média dos machos foi de 37,4 semanas e a das fêmeas de 36,8.O tempo médio de desenvolvimento foi de 61,7 semanas. A taxa reprodutiva líquida indica que esta população aumentará 143,2 vezes durante cada geração. A taxa intrínseca do crecimento natural foi de 0,082 por semana. A média do valor máximo reprodutivo

  11. Experimental investigation of shock wave - bubble interaction

    Energy Technology Data Exchange (ETDEWEB)

    Alizadeh, Mohsen

    2010-04-09

    In this work, the dynamics of laser-generated single cavitation bubbles exposed to lithotripter shock waves has been investigated experimentally. The energy of the impinging shock wave is varied in several steps. High-speed photography and pressure field measurements simultaneously with image acquisition provide the possibility of capturing the fast bubble dynamics under the effect of the shock wave impact. The pressure measurement is performed using a fiber optic probe hydrophone (FOPH) which operates based on optical diagnostics of the shock wave propagating medium. After a short introduction in chapter 1 an overview of the previous studies in chapter 2 is presented. The reported literatures include theoretical and experimental investigations of several configurations of physical problems in the field of bubble dynamics. In chapter 3 a theoretical description of propagation of a shock wave in a liquid like water has been discussed. Different kinds of reflection of a shock wave at an interface are taken into account. Undisturbed bubble dynamics as well as interaction between a planar shock wave and an initially spherical bubble are explored theoretically. Some physical parameters which are important in this issue such as the velocity of the shock-induced liquid jet, Kelvin impulse and kinetic energy are explained. The shock waves are generated in a water filled container by a focusing piezoelectric generator. The shock wave profile has a positive part with pulse duration of ∼1 μs followed by a longer tension tail (i.e. ∼3 μs). In chapter 4 high-speed images depict the propagation of a shock wave in the water filled tank. The maximum pressure is also derived for different intensity levels of the shock wave generator. The measurement is performed in the free field (i.e. in the absence of laser-generated single bubbles). In chapter 5 the interaction between lithotripter shock waves and laserinduced single cavitation bubbles is investigated experimentally. An

  12. Se analiza la teoría de Jorge Juan sobre la resistencia fluídica, tal como la expone en el Examen

    Directory of Open Access Journals (Sweden)

    Simón Calero, Julián

    2001-12-01

    Full Text Available The Jorge Juan theory on fluid resistance is analysed as stated in the Examen Marítimo. The theoretical basis and applications are studied, these range from flat plates to ship hull and sails. The article concludes with a revision of what Juan considers to be its experimental basis and possible forerunners of his theory are traced.

    Se analiza la teoría de Jorge Juan sobre la resistencia fluídica, tal como la expone en el Examen Marítimo. Se estudian las bases teóricas y sus aplicaciones, desde placas planas hasta cacos y velas de buques. Se concluye con una revisión de lo que Juan considera sus fundamentos experimentales y se rastrean los posibles antecedentes de su teoría.

  13. Geomagnetic avtivity triggered by interplanetary shocks: The shock impact angle as a controlling factor

    Science.gov (United States)

    Oliveira, D. M.; Raeder, J.; Tsurutani, B.; Gjerloev, J. W.

    2015-12-01

    We study the influence of interplanetary (IP) shock impact angles in the shock geoeffectiveness focusing on simulations and observations. In our simulations, we use OpenGGCM simulations to study the magnetospheric and ionospheric responses to shock impacts. Three cases are presented here: two inclined shocks, with 3.7 and 7.4 Mach numbers, and a frontal shock, whose shock normal is along the Sun-Earth line, with Mach number of 7.4. We find that, in the two inclined cases, due to the north-south asymmetry, the magnetotail is deflected southward, leading to a mild compression. The geomagnetic activity observed in the nightside ionosphere is then weak. On the other hand, in the head-on case, the magnetotail is compressed from both sides symmetrically. This compression triggers a substorm. By comparing the strong inclined shock and the frontal shock, we find that, despite the inclined shock having a larger Mach number, the frontal shock leads to a larger geomagnetic response in the nightside ionosphere. As a result, we conclude that IP shocks with similar upstream conditions, such as Mach number, can have different geoeffectiveness, depending on their shock normal orientation. In our observational study, we present a survey of IP shocks at 1 AU using Wind and ACE satellite data from Jan 1995 to Dec 2013 to study the same shock-related effects. A shock list covering one and a half solar cycle is compiled. We use data from SuperMAG, a large chain with more than 300 geomagnetic stations, to study geoeffectiveness triggered by IP shocks. The SuperMAG SML index (enhanced AL index), is used to quantify substorm strength. The jumps of the SML index triggered by shock impacts is investigated in terms of shock orientation and speed. We find that, in general, strong and almost frontal shocks are more geoeffective than inclined shocks with low speed. The highest correlations (R = 0.78) occurs for fixed shock speed and varying the shock impact angle. We attribute this result

  14. EFECTO DE LA ADICIÓN DE NITRATOS A LA DIETA SOBRE LA MORTALID AD DE POLLOS BROILER

    Directory of Open Access Journals (Sweden)

    C. Orozco Sanabria

    2010-01-01

    Full Text Available Objetivos: este estudio investigó el efecto de la adición de nitratos en la dieta sobre la mortalidad de pollos broiler. Materiales y métodos: se utilizaron 100 pollos de estirpe Ross de un día de nacidos, divididos aleatoriamente en cuatro grupos. Se cuantificó el contenido de nitratos en el pienso comercial y el agua de bebida por una técnica colorimétrica basada en la nitridación del ácido sulfúrico. Los sujetos experimentales de los cuatro grupos recibieron pienso y agua ad libitum en las cantidades recomendadas para pollos broiler. Los animales de tres de los grupos recibieron nitrato de sodio adicional en el agua de bebida. La adición de nitrato fue 1, 2 ó 3 veces la concentración hallada en el pienso. Resultados: la adición de nitrato en el agua de bebida resultó en aumento de la mortalidad en relación dosis dependiente con la concentración adicionada. El análisis patológico realizado el último día del ciclo a los animales sobrevivientes de cada uno de los grupos experimentales demostró que aquellos expuestos a las mayores adiciones de nitrato presentaron lesiones compatibles con el síndrome ascítico. Adicionalmente, los hallazgos de necropsia en los animales que fallecieron durante el experimento mostraron lesiones compatibles con enfermedades infecciosas y con la enfermedad de edema aviar. Conclusiones: los resultados de este estudio sugieren que el consumo de nitratos representa un factor determinante para el aumento de la mortalidad en las explotaciones avícolas.

  15. Sobre crescimento economico otimo

    OpenAIRE

    Jose Benedito Schneider

    1982-01-01

    Resumo: No Capitulo I, após apresentaçâo do debate sobre implicações ideológicas no uso da Matemãtica em Economia, é feita uma análise das principais linhas teóricas dos modelos de crescimento econômico. Essa análise tem como referencial a instabilidade inerente ao crescimento da economia capitalista, demonstrada no modelo de Harrod-Dornar. Termina definindo a teoria de crescimento econômico ótimo, mostrando porque o modelo de von Neumann é o mais significativo desta classe. o Capitulo I...

  16. Visiones sobre el poder

    OpenAIRE

    Vélez Vélez, Marco Antonio

    2007-01-01

    Las siguientes consideraciones se ocuparán de concepciones sobre el poder, emanadas de teóricos con diversa orientación epistémica e ideológica, tan disímiles como pueden ser los nombres de Marx, Foucault, Luhmann, Max Weber y Elías Canetti. Coinciden los primeros en una apreciación estructural del poder más allá de sus divergencias en el enfoque del mismo. The following considerations will deal with conceptions about the power emanating from diverse theoretical and ideologi...

  17. Entropy Generation Across Earth's Bow Shock

    Science.gov (United States)

    Parks, George K.; McCarthy, Michael; Fu, Suiyan; Lee E. s; Cao, Jinbin; Goldstein, Melvyn L.; Canu, Patrick; Dandouras, Iannis S.; Reme, Henri; Fazakerley, Andrew; hide

    2011-01-01

    Earth's bow shock is a transition layer that causes an irreversible change in the state of plasma that is stationary in time. Theories predict entropy increases across the bow shock but entropy has never been directly measured. Cluster and Double Star plasma experiments measure 3D plasma distributions upstream and downstream of the bow shock that allow calculation of Boltzmann's entropy function H and his famous H-theorem, dH/dt O. We present the first direct measurements of entropy density changes across Earth's bow shock. We will show that this entropy generation may be part of the processes that produce the non-thermal plasma distributions is consistent with a kinetic entropy flux model derived from the collisionless Boltzmann equation, giving strong support that solar wind's total entropy across the bow shock remains unchanged. As far as we know, our results are not explained by any existing shock models and should be of interests to theorists.

  18. Entropy generation across Earth's collisionless bow shock.

    Science.gov (United States)

    Parks, G K; Lee, E; McCarthy, M; Goldstein, M; Fu, S Y; Cao, J B; Canu, P; Lin, N; Wilber, M; Dandouras, I; Réme, H; Fazakerley, A

    2012-02-10

    Earth's bow shock is a collisionless shock wave but entropy has never been directly measured across it. The plasma experiments on Cluster and Double Star measure 3D plasma distributions upstream and downstream of the bow shock allowing calculation of Boltzmann's entropy function H and his famous H theorem, dH/dt≤0. The collisionless Boltzmann (Vlasov) equation predicts that the total entropy does not change if the distribution function across the shock becomes nonthermal, but it allows changes in the entropy density. Here, we present the first direct measurements of entropy density changes across Earth's bow shock and show that the results generally support the model of the Vlasov analysis. These observations are a starting point for a more sophisticated analysis that includes 3D computer modeling of collisionless shocks with input from observed particles, waves, and turbulences.

  19. Advances in Monitoring and Management of Shock

    Science.gov (United States)

    Mtaweh, Haifa; Trakas, Erin V.; Su, Erik; Carcillo, Joseph A.; Aneja, Rajesh K.

    2013-01-01

    Synopsis Shock continues to be the proximate cause of death for many childhood diseases and imposes a significant burden. Early recognition and treatment of pediatric shock, regardless of etiology, decreases mortality and improves outcome. In addition to the conventional parameters (e.g., heart rate (HR), systolic blood pressure (SBP), urine output (UOP), and central venous pressure (CVP)), biomarkers and non-invasive methods of measuring cardiac output are now available to monitor and treat shock. In this article, we emphasize how fluid resuscitation is the cornerstone of shock resuscitation although the choice and amount of fluid may vary based on the etiology of shock. Other emerging treatments for shock i.e., temperature control, extracorporeal membrane oxygenation (ECMO)/Ventricular Assist Devices (VAD) are also discussed briefly in this article. PMID:23639660

  20. Shock heating of the solar wind plasma

    Science.gov (United States)

    Whang, Y. C.; Liu, Shaoliang; Burlaga, L. F.

    1990-01-01

    The role played by shocks in heating solar-wind plasma is investigated using data on 413 shocks which were identified from the plasma and magnetic-field data collected between 1973 and 1982 by Pioneer and Voyager spacecraft. It is found that the average shock strength increased with the heliocentric distance outside 1 AU, reaching a maximum near 5 AU, after which the shock strength decreased with the distance; the entropy of the solar wind protons also reached a maximum at 5 AU. An MHD simulation model in which shock heating is the only heating mechanism available was used to calculate the entropy changes for the November 1977 event. The calculated entropy agreed well with the value calculated from observational data, suggesting that shocks are chiefly responsible for heating solar wind plasma between 1 and 15 AU.

  1. Shock-induced phase transformation in tantalum.

    Science.gov (United States)

    Hsiung, Luke L

    2010-09-29

    A TEM study of pure tantalum and tantalum-tungsten alloys explosively shocked at a peak pressure of 30 GPa is presented. While no omega phase was found in shock-recovered pure Ta and Ta-5W which mainly contain a cellular dislocation structure, a shock-induced omega phase was found in Ta-10W which contains evenly distributed dislocations with a density higher than 1 × 10(12) cm( - 2). The shock-induced [Formula: see text] (hexagonal) transition occurs when the dynamic recovery of dislocations becomes largely suppressed in Ta-10W shocked under dynamic-pressure conditions. A dislocation-based mechanism is proposed for the shock-induced phase transformation.

  2. Remote shock sensing and notification system

    Energy Technology Data Exchange (ETDEWEB)

    Muralidharan, Govindarajan [Knoxville, TN; Britton, Charles L [Alcoa, TN; Pearce, James [Lenoir City, TN; Jagadish, Usha [Knoxville, TN; Sikka, Vinod K [Oak Ridge, TN

    2010-11-02

    A low-power shock sensing system includes at least one shock sensor physically coupled to a chemical storage tank to be monitored for impacts, and an RF transmitter which is in a low-power idle state in the absence of a triggering signal. The system includes interface circuitry including or activated by the shock sensor, wherein an output of the interface circuitry is coupled to an input of the RF transmitter. The interface circuitry triggers the RF transmitter with the triggering signal to transmit an alarm message to at least one remote location when the sensor senses a shock greater than a predetermined threshold. In one embodiment the shock sensor is a shock switch which provides an open and a closed state, the open state being a low power idle state.

  3. Exhaust Nozzle Plume and Shock Wave Interaction

    Science.gov (United States)

    Castner, Raymond S.; Elmiligui, Alaa; Cliff, Susan

    2013-01-01

    Fundamental research for sonic boom reduction is needed to quantify the interaction of shock waves generated from the aircraft wing or tail surfaces with the exhaust plume. Both the nozzle exhaust plume shape and the tail shock shape may be affected by an interaction that may alter the vehicle sonic boom signature. The plume and shock interaction was studied using Computational Fluid Dynamics simulation on two types of convergent-divergent nozzles and a simple wedge shock generator. The nozzle plume effects on the lower wedge compression region are evaluated for two- and three-dimensional nozzle plumes. Results show that the compression from the wedge deflects the nozzle plume and shocks form on the deflected lower plume boundary. The sonic boom pressure signature of the wedge is modified by the presence of the plume, and the computational predictions show significant (8 to 15 percent) changes in shock amplitude.

  4. Remote shock sensing and notification system

    Science.gov (United States)

    Muralidharan, Govindarajan; Britton, Charles L.; Pearce, James; Jagadish, Usha; Sikka, Vinod K.

    2008-11-11

    A low-power shock sensing system includes at least one shock sensor physically coupled to a chemical storage tank to be monitored for impacts, and an RF transmitter which is in a low-power idle state in the absence of a triggering signal. The system includes interference circuitry including or activated by the shock sensor, wherein an output of the interface circuitry is coupled to an input of the RF transmitter. The interface circuitry triggers the RF transmitting with the triggering signal to transmit an alarm message to at least one remote location when the sensor senses a shock greater than a predetermined threshold. In one embodiment the shock sensor is a shock switch which provides an open and a closed state, the open state being a low power idle state.

  5. Shock-induced deformation twinning in tantalum

    Energy Technology Data Exchange (ETDEWEB)

    Murr, L.E.; Niou, C.S.; Pappu, S.; Kennedy, C. [Univ. of Texas, El Paso, TX (United States). Dept. of Metallurgical and Materials Engineering; Meyers, M.A.; Chen, Y.J. [Univ. of California, San Diego, La Jolla, CA (United States). Dept. of Applied Mechanics and Engineering Sciences

    1997-01-01

    Shock-wave deformation of tantalum to a pressure of 45 GPa and duration of 1.8 {micro}s generates profuse twinning. The post-shock mechanical response is significantly affected, with shock hardening exceeding the expected hardening due to the transient shock strain {epsilon}{sub s} = (4/3)ln(V/V{sub 0}); this enhanced hardening, and other alterations in response, are attributed to the barriers presented to plastic deformation by the deformation twins. A constitutive model is proposed that predicts the threshold shock stress for mechanical twinning; it is based on the application of the Swegle-Grady relationship between shock stress and strain rate to constitute equations describing the critical stress for slip and twinning. This constitutive model incorporates grain-size effects and predicts a threshold twinning stress that is a function of temperature and grain size; predictions of the model are in qualitative agreement with experimental results.

  6. Efectos sobre la disposición sagital del raquis de un programa de Educación Postural en Educación Física de Primaria

    Directory of Open Access Journals (Sweden)

    Pilar Sainz de Baranda

    2010-09-01

    Full Text Available El objetivo fue analizar el efecto de un programa de educación postural sobre el plano sagital de la columna vertebral. Un total de 80 escolares se dividieron en tres grupos (2 experimentales y 1 grupo control. Los grupos experimentales realizaron el programa de educación postural dentro de las clases de Educación Física de primaria durante un curso escolar completo (9 meses, dos sesiones por semana (31 semanas, 62 sesiones de Educación Física. El programa desarrollaba los contenidos de toma de conciencia, fortalecimiento abdominal y lumbar y estiramientos de la musculatura isquiosural. Para su desarrollo se utilizó un tiempo de 17 minutos de la sesión habitual de Educación Física. El grupo control siguió el programa estándar de las clases de Educación Física. Previo a la aplicación del programa y posteriormente se valoró con un inclinómetro ISOMED-95 el plano sagital de la columna vertebral en tres posiciones: bipedestación, flexión de tronco y sedentación. Los resultados muestran mejoras en ambos grupos experimentales en todas las valoraciones, aunque solo son significativas en la flexión de tronco y sedentación. Para el grupo control, no se encontraron mejoras en ningún parámetro, empeorando tanto la disposición sagital estática (bipedestación como la dinámica (flexión de tronco y sedentación. Conclusiones: la realización de un programa de educación postural dentro de las clases de Educación Física mejora de forma global la disposición sagital del raquis de los escolares.

  7. Mortality rates in pediatric septic shock

    OpenAIRE

    Desy Rusmawatiningtyas; Nurnaningsih Nurnaningsih

    2017-01-01

    Background Septic shock remains a major cause of morbidity and mortality in children admitted to the intensive care unit. Recent investigations from developed countries have reported mortality rates of 20-30%. Few studies have reported mortality rates from pediatric septic shock in intensive care settings in developing countries with limited resources.  Objective  To determine the current mortality rates for pediatric patients with septic shock in a developing country. Methods A retr...

  8. Pyrotechnic Shock Analysis Using Statistical Energy Analysis

    Science.gov (United States)

    2015-10-23

    29th Aerospace Testing Seminar, October 2015 Pyrotechnic Shock Analysis Using Statistical Energy Analysis James Ho-Jin Hwang Engineering...maximum structural response due to a pyrotechnic shock input using Statistical Energy Analysis (SEA). It had been previously understood that since the...pyrotechnic shock is not a steady state event, traditional SEA method may not applicable. A new analysis methodology effectively utilizes the

  9. Balmer-Dominated Shocks: A Concise Review

    OpenAIRE

    Heng, Kevin

    2009-01-01

    A concise and critical review of Balmer-dominated shocks (BDSs) is presented, summarizing the state of theory and observations, including models with/without shock precursors and their synergy with atomic physics. Observations of BDSs in supernova remnants are reviewed on an object-by-object basis. The relevance of BDSs towards understanding the acceleration of cosmic rays in shocks is emphasized. Probable and possible detections of BDSs in astrophysical objects other than supernova remnants,...

  10. Compressible gas properties of UF/sub 6/ for isentropic, normal shock, and oblique shock conditions

    Energy Technology Data Exchange (ETDEWEB)

    Harloff, G.J.

    1984-11-01

    Isentropic, normal shock, and oblique shock tables are given for the real gas UF/sub 6/ for Mach numbers up to 22. An evaluation of the real gas effects is given. A computer program listing is included.

  11. Role of echocardiography in reducing shock reversal time in pediatric septic shock: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Ahmed A. EL‐Nawawy

    2018-01-01

    Conclusion: Serial echocardiography provided crucial data for early recognition of septic myocardial dysfunction and hypovolemia that was not apparent on clinical assessment, allowing a timely management and resulting in shock reversal time reduction among children with septic shock.

  12. Sobre historia mundial hoy

    Directory of Open Access Journals (Sweden)

    Vera Weiler

    2001-01-01

    Full Text Available Los procesos de globalización son una realidad; su enorme impacto sobre la vida humana los ha convertido en un tema recurrente sobre el que se escribe y se comenta a diario también en Colombia. Los libros que de ellos tratan, ante todo los que 10 hacen en tono crítico, baten records en la industria editorial en todo el mundo. Las expectativas que acerca del futuro abrigan cientos de millones de personas se relacionan con 10 que ellas esperan, para bien o para mal, de la globalización. Las posturas que los gobernantes ocupan al respecto en el mundo son, cuando menos de aceptación, generalmente de activa participación en pos de la globalización. Por un lado, crece la preocupación y se multiplican las protestas; por el otro, dominan los razonamientos de los especialistas en materia de maximización de los rendimientos de los capitales que presentan la globalización, al estilo que se viene imponiendo, como el camino ineludible del gobierno universal de la eficiencia. ¿Tienen que decir algo los historiadores frente a todo esto?.

  13. Advanced and Exploratory Shock Sensing Mechanisms.

    Energy Technology Data Exchange (ETDEWEB)

    Nelsen, Nicholas H. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kolb, James D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kulkarni, Akshay G. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sorscher, Zachary [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Habing, Clayton D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Mathis, Allen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Beller, Zachary J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-09-01

    Mechanical component response to shock environments must be predictable in order to ensure reliability and safety. Whether the shock input results from accidental drops during transportation to projectile impact scenarios, the system must irreversibly transition into a safe state that is incapable of triggering the component . With this critical need in mind, the 2017 Nuclear Weapons Summer Product Realization Institute (NW SPRINT) program objective sought the design of a passive shock failsafe with emphasis on additively manufactured (AM) components. Team Advanced and Exploratory (A&E) responded to the challenge by designing and delivering multiple passive shock sensing mech anisms that activate within a prescribed mechanical shock threshold. These AM failsafe designs were tuned and validated using analytical and computational techniques including the shock response spectrum (SRS) and finite element analysis (FEA). After rapid prototyping, the devices experienced physical shock tests conducted on Sandia drop tables to experimentally verify performance. Keywords: Additive manufacturing, dynamic system, failsafe, finite element analysis, mechanical shock, NW SPRINT, shock respon se spectrum

  14. Journal of emergencies, trauma and shock

    National Research Council Canada - National Science Library

    JETS encourages research, education and dissemination of knowledge in the fields of emergency medicine, traumatology and shock resuscitation thus promoting translational research by striking a synergy...

  15. Loxosceles arizonica bite associated with shock.

    Science.gov (United States)

    Bey, T A; Walter, F G; Lober, W; Schmidt, J; Spark, R; Schlievert, P M

    1997-11-01

    Envenomation by the brown recluse spider (Loxosceles reclusa) is associated with shock, significant hemolysis, renal insufficiency, and disseminated intravascular coagulation (DIC). Shock has never been associated with envenomation by L arizonica, a related species indigenous to Arizona, southern California, and northwestern Mexico. We report the case of a 13-year-old girl, bitten by a specimen of L arizonica (the spider was identified by an entomologist), in whom shock and a typical cutaneous lesion developed. She did not experience renal insufficiency or disseminated intravascular coagulation. Infectious causes of shock were excluded. She recovered completely with supportive care.

  16. Basic Shock Physiology and Critical Care.

    Science.gov (United States)

    Roberts, Brian K

    2016-05-01

    Veterinarians practicing emergency medicine and/or working with exotic animals must be well versed in the pathophysiology of shock because many exotic pets present with an acute crisis or an acute manifestation of a chronic process causing poor organ perfusion. This article discusses the pathophysiology of shock and the systemic inflammatory response syndrome, which may lead to organ dysfunction, organ failure, sepsis, and death. The physiology of perfusion, perfusion measurements, categories of shock, and altered function of the immune system, gastrointestinal barrier, and coagulation system are discussed. Veterinarians providing emergency care to patients with shock must also be aware of comorbidities. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Thermal Shock-resistant Cement

    Energy Technology Data Exchange (ETDEWEB)

    Sugama T.; Pyatina, T.; Gill, S.

    2012-02-01

    We studied the effectiveness of sodium silicate-activated Class F fly ash in improving the thermal shock resistance and in extending the onset of hydration of Secar #80 refractory cement. When the dry mix cement, consisting of Secar #80, Class F fly ash, and sodium silicate, came in contact with water, NaOH derived from the dissolution of sodium silicate preferentially reacted with Class F fly ash, rather than the #80, to dissociate silicate anions from Class F fly ash. Then, these dissociated silicate ions delayed significantly the hydration of #80 possessing a rapid setting behavior. We undertook a multiple heating -water cooling quenching-cycle test to evaluate the cement’s resistance to thermal shock. In one cycle, we heated the 200 and #61616;C-autoclaved cement at 500 and #61616;C for 24 hours, and then the heated cement was rapidly immersed in water at 25 and #61616;C. This cycle was repeated five times. The phase composition of the autoclaved #80/Class F fly ash blend cements comprised four crystalline hydration products, boehmite, katoite, hydrogrossular, and hydroxysodalite, responsible for strengthening cement. After a test of 5-cycle heat-water quenching, we observed three crystalline phase-transformations in this autoclaved cement: boehmite and #61614; and #61543;-Al2O3, katoite and #61614; calcite, and hydroxysodalite and #61614; carbonated sodalite. Among those, the hydroxysodalite and #61614; carbonated sodalite transformation not only played a pivotal role in densifying the cementitious structure and in sustaining the original compressive strength developed after autoclaving, but also offered an improved resistance of the #80 cement to thermal shock. In contrast, autoclaved Class G well cement with and without Class F fly ash and quartz flour failed this cycle test, generating multiple cracks in the cement. The major reason for such impairment was the hydration of lime derived from the dehydroxylation of portlandite formed in the autoclaved

  18. Investigation of shock focusing in a cavity with incident shock diffracted by an obstacle

    Science.gov (United States)

    Zhang, Q.; Chen, X.; He, L.-M.; Rong, K.; Deiterding, R.

    2017-03-01

    Experiments and numerical simulations were carried out in order to investigate the focusing of a shock wave in a test section after the incident shock has been diffracted by an obstacle. A conventional shock tube was used to generate the planar shock. Incident shock Mach numbers of 1.4 and 2.1 were tested. A high-speed camera was employed to obtain schlieren photos of the flow field in the experiments. In the numerical simulations, a weighted essentially non-oscillatory (WENO) scheme of third-order accuracy supplemented with structured dynamic mesh adaptation was adopted to simulate the shock wave interaction. Good agreement between experiments and numerical results is observed. The configurations exhibit shock reflection phenomena, shock-vortex interaction and—in particular—shock focusing. The pressure history in the cavity apex was recorded and compared with the numerical results. A quantitative analysis of the numerically observed shock reflection configurations is also performed by employing a pseudo-steady shock transition boundary calculation technique. Regular reflection, single Mach reflection and transitional Mach reflection phenomena are observed and are found to correlate well with analytic predictions from shock reflection theory.

  19. Validez Estructurada para una investigación cuasi-experimental de calidad: se cumplen 50 años de la presentación en sociedad de los diseños cuasi-experimentales

    Directory of Open Access Journals (Sweden)

    Paula Fernández-García

    2014-05-01

    Full Text Available Investigación cuasi-experimental es aquella que tiene como objetivo poner a prueba una hipótesis causal manipulando (al menos una variable independiente donde por razones logísticas o éticas no se puede asignar las unidades de investigación aleatoriamente a los grupos. Debido a que muchas decisiones a nivel social se toman en base al resultado de investigaciones con estas características, es imperativo que tengan una planificación exquisita de la aplicación del tratamiento, del control en el proceso de la investigación y del análisis de los datos. El pasado año 2013 los diseños cuasi-experimentales cumplieron 50 años, y este trabajo es un homenaje a Campbell y a todos los investigadores que día a día aportan ideas para mejorar el método cuasi-experimental en alguno de sus aspectos. De la mano de una revisión de las investigaciones cuasi-experimentales publicadas en un período de 11 años en tres revistas de Psicología destacamos algunos aspectos que se refieren al cuidado del método. Finalizamos el trabajo proponiendo el concepto de Validez Estructurada, que en resumen, es el hilo conductor que debe seguir la realización de toda investigación para poner a prueba con garantía las hipótesis que responden a los objetivos que en ella se plantean, concretamente, en las investigaciones cuasi-experimentales.

  20. Experimental study of contamination by inhalation of radioactive iodine aerosols. Biological balance; Etude experimentale de la contamination par inhalation d'aerosols d'iode radioactif bilan biologique

    Energy Technology Data Exchange (ETDEWEB)

    Marble, G. [Commissariat a l' Energie Atomique, 92 - Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1968-07-01

    Several articles have been published concerning research into contamination produced by inhalation of radioactive iodine aerosols in monkeys. Results dealing with the biological balance of this contamination are presented and discussed in this report. (author) [French] L'etude experimentale de la contamination par inhalation d'aerosols d'iode radioactif effectuee chez le singe a fait l'objet de plusieurs publications. Les resultats concernant le bilan biologique de cette contamination sont presentes et discutes dans ce rapport. (auteur)

  1. Propuesta didáctica basada en la Metodología de Aprendizaje Activo, encaminada a construir el concepto de difracción partiendo de prácticas experimentales

    OpenAIRE

    Manrique Torres, Carolina

    2012-01-01

    Este trabajo presenta una propuesta didáctica para docentes de secundaria basada en la metodología de aprendizaje activo (MAA), encaminada a construir el concepto de difracción por medio de prácticas experimentales realizadas en el aula de clase, por los estudiantes de grado undécimo en la asignatura de física. La difracción es un fenómeno de la óptica ondulatoria que ha permitido importantes aportes en el estudio de la física y que además puede evidenciarse fácilmente en un laboratorio y en ...

  2. HIDRODENITROGENACION DE CARBAZOL SOBRE CATALIZADORES NiMo/Al2O3-SiO2(x

    Directory of Open Access Journals (Sweden)

    Felipe Sánchez-Minero

    2012-01-01

    Full Text Available En este trabajo se estudió la velocidad de reacción del carbazol sobre catalizadores NiMo soportados sobre Al2O3 modificada superficialmente con SiO2 (0 y 10 % en peso de SiO2 en el soporte. Los catalizadores fueron evaluados en un reactor intermitente a cuatro temperaturas (287, 300, 312 y 325oC, presión de 4.0 MPa y relación molar hidrogeno/carbazol de 2400. A partir de los resultados experimentales se realizó un estudio cinético utilizando ecuaciones del tipo Langmuir-Hinshelwood (L-H. Luego, los parámetros cinéticos fueron estimados mediante la minimización de Powell (programa Scientist de MicroMath. Los resultados muestran que el catalizador con sílice (NiMo-SAC 10 alcanza una mayor actividad para la HDN de carbazol debido a que presenta un mayor número de sitios activos (valor de A, así como una menor fuerza de adsorción entre el reactante y la superficie catalítica (valor de KN, lo cual posiblemente favorece una mejor regeneración de sitios activos.

  3. Multiscale Modeling of Shocked Ceramics

    Science.gov (United States)

    Feng, Ruqiang; Zhu, Jianbin

    2007-06-01

    Under shock compression, polycrystalline ceramics may undergo mesoscopically heterogeneous inelastic deformation via transgranular slip or twinning in some grains. Although polycrystal modeling, which accounts for crystal anisotropies and grain-to-grain topological variations and permits implementation of crystal plasticity models of interest, may be used to analyze such a deformation, the size affordable is too small to run wave propagation simulations needed to extract material properties from a plate impact experiment. To address this issue, we have developed a multiscale modeling technique, in which a Voronoi polycrystal is embedded in a homogeneous matrix of the size proper for simulating the experiment. The polycrystal model considers nonlinear crystal elasticity and microplasticity by limited slip systems. The matrix model uses the mean stress response predicted by elastic polycrystal simulation and a strength model combining the Drucker-Prager plasticity with a prescribed limiting strength. Two parametric optimizations are pursed iteratively. One is to optimize the matrix parameters to match the simulated wave profile with the measurement. The other is to optimize the polycrystal parameters to match the triaxial stress-strain curves volume-averaged over the polycrystal to those of the matrix. The technique has been applied to analyze the inelastic deformations of shocked alumina and silicon carbide. The results will be presented for demonstration.

  4. Massive transfusion in traumatic shock.

    Science.gov (United States)

    Elmer, Jonathan; Wilcox, Susan R; Raja, Ali S

    2013-04-01

    Hemorrhage after trauma is a common cause of death in the United States and globally. The primary goals when managing traumatic shock are the restoration of oxygen delivery to end organs, maintenance of circulatory volume, and prevention of ongoing bleeding through source control and correction of coagulopathy. Achieving these goals may require massive transfusion of blood products. Although use of blood products may be lifesaving, dose-related adverse effects are well described. Complications of massive transfusion include interdependent derangements such as coagulopathy, hypothermia, acidosis, and electrolyte abnormalities, as well as infectious and immunomodulatory phenomena. This article explores the pathogenesis, implications, prevention, and treatment of these complications through the use of massive transfusion protocols. Particular attention is given to the optimal ratio of blood products transfused in large volume resuscitation and prevention of secondary coagulopathy. Observational data indicate that the development and use of a massive transfusion protocol may reduce the morbidity and mortality associated with large-volume resuscitation of patients with hemorrhagic shock. Such protocols should include a pre-defined ratio of packed red blood cells, fresh frozen plasma, and platelets transfused; most commonly, the ratio used is 1:1:1. Additionally, such protocols should monitor for and correct hypothermia, hypofibrinogenemia, and electrolyte disturbances such as hypocalcemia and hyperkalemia. Copyright © 2013. Published by Elsevier Inc.

  5. Sobre la forma muncho

    OpenAIRE

    Pato, Enrique

    2013-01-01

    La presente nota aporta luz nueva sobre la historia y la evolución de muncho en español. En primer lugar, los ejemplos presentados confirman que estamos ante un fenómeno antiguo, documentado en el mismo latín, y característico del español clásico. Estudiamos la variación que ha mantenido con la forma estándar mucho a lo largo de la historia y, gracias a los datos del ALPI y del COSER, damos a conocer su extensión geográfica. La –n– parasitaria se documenta también en otras lenguas y dialectos...

  6. The Shock and Vibration Bulletin. Part 3. Shock Testing, Shock Analysis

    Science.gov (United States)

    1974-08-01

    DYNAMICAL SYSTEMS UNDER NONSTATIONARY RANDOM EXCITATIONS T.S. Sankar and D. Doan, Sir George Williams University, Montreal, Canada MEANS OF CONTROLLING... George J. O’Hara "Effect Upon Shock ""ofthe velocity, and displacement requirements of the Dynamic Reactionof c C difficilt. A method has been...changes of step size will be required. 2 - e •,•At - (-1 The exact forms of T, M1, and M 2 may be obtained by application of the Cayley -1lamilton

  7. Notas sobre o marcellismo

    Directory of Open Access Journals (Sweden)

    Jorge Sampaio

    2007-01-01

    Full Text Available Para el salazarismo, la estabilidad consistía en erradicar de la sociedad la elección de alternativas, esto es el conflicto. Ese orden comenzó a desmoronarse sobre todo desde los años 60, como consecuencia de los cambios socioeconómicos y culturales que acentuaban los factores de información y de concurrencia en la sociedad portuguesa. Ante este nuevo panorama, el éxito de Marcelo Caetano sólo era posible mediante un compromiso con los nuevos actores sociales y con las nuevas fuerzas políticas empeñadas en la instauración de la democracia. Sin embargo el Presidente del Consejo no quiso o no pudo asumir ese compromiso, viéndose obligado al cabo de un tiempo a volver sobre sus iniciales pasos aperturistas.The social and political stability under salazarism was contemplated as a result of alternatives choice and conflicts suppression. That order was mainly eroding along the decade of sixteenth as a consequence of social, economic and cultural changes that were accentuating information and concurrence factors in Portuguese society. Facing this new stage, the success of Marcelo Caetano’s reformism was depending on his capacity of commitment with the new social actors and the opposition political forces solidly engage in democratic goal. However, the President wasn’t capable —or wasn’t allowed— to assume this commitment, even reversing after the first hopeful times his initial reformist trends.

  8. Una Teoría sobre el Conocimiento Intersubjetivo Implícito

    Directory of Open Access Journals (Sweden)

    Emilce Dio Bleichmar

    2009-01-01

    Full Text Available Daniel Stern es autor de una teoría de la subjetividad y conciencia prelingüística. Estudia e investiga la relación temprana intentando inferir probables experiencias subjetivas de los infantes en el período preverbal. Toma en cuenta los hallazgos experimentales sobre el desarrollo de la década de los setenta, en conjunción con los fenómenos clínicos derivados de la práctica. Un paso hacia la síntesis del infante observado y del reconstruido por la clínica psicoanalítica. Un serio intento para identificar y rastrear pautas interactivas a lo largo de sus transformaciones evolutivas tomando el sentido de sí mismo como organizador del desarrollo. Stern contribuye a establecer la naturaleza relacional del sí mismo y por medio de estudios "microclínicos" escenarios de los fenómenos relacionales de regulación o desrregulación emocional. Propone y desarrolla un modelo de psicoterapia de la relación entre padres e hijos con especial acento en lo que define como el present moment de la experiencia intersubjetiva, insistiendo y mostrando que es en esos momentos del diálogo donde descansa el efecto mutativo de la psicoterapia. Lo significativo en psicoterapia son las formas de estar con otros que es lo que puede ayudarnos a reescribir el pasado y el futuro.

  9. Estabilidad y efecto de la ingestión sobre los niveles de folatos en plasma

    Directory of Open Access Journals (Sweden)

    Visitación Noy

    2002-03-01

    Full Text Available La demanda fisiológica de folatos se incrementa durante la adolescencia, embarazo y lactancia debido al rápido crecimiento y actividad anabólica durante estas etapas de la vida. La deficiencia de folatos antes de la concepción y durante los primeros meses de embarazo constituye un riesgo para la presencia de defectos en el tubo neural. Se investigó la estabilidad de la concentración de folatos en muestras de plasma y el efecto de la ingestión de un desayuno rico en folatos sobre los niveles postprandiales de este micronutriente en plasma, hasta dos horas después de ingerirlo. Para los ensayos de estabilidad, las muestras se almacenaron protegidas de la luz a -70 °C y se analizaron a intervalos de tiempo de 1, 8, 30, 90 y 120 días. La concentración promedio de folatos en plasma fue mayor en la fase postprandial (8,9 ng/ml que en ayunas (7,9 ng/dl, lo que representa un incremento del 11%, que es estadísticamente significativo (p0,1; esto sugiere que la concentración de folatos en plasma permanece estable bajo las condiciones experimentales descritas.

  10. Optical observation of shock waves and cavitation bubbles in high intensity laser-induced shock processes.

    Science.gov (United States)

    Martí-López, L; Ocaña, R; Porro, J A; Morales, M; Ocaña, J L

    2009-07-01

    We report an experimental study of the temporal and spatial dynamics of shock waves, cavitation bubbles, and sound waves generated in water during laser shock processing by single Nd:YAG laser pulses of nanosecond duration. A fast ICCD camera (2 ns gate time) was employed to record false schlieren photographs, schlieren photographs, and Mach-Zehnder interferograms of the zone surrounding the laser spot site on the target, an aluminum alloy sample. We recorded hemispherical shock fronts, cylindrical shock fronts, plane shock fronts, cavitation bubbles, and phase disturbance tracks.

  11. Introduction to Shock Waves and Shock Wave Research

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, William Wyatt [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-02

    M-9 and a number of other organizations at LANL and elsewhere study materials in dynamic processes. Often, this is described as “shock wave research,” but in reality is broader than is implied by that term. Most of our work is focused on dynamic compression and associated phenomena, but you will find a wide variety of things we do that, while related, are not simple compression of materials, but involve a much richer variety of phenomena. This tutorial will introduce some of the underlying physics involved in this work, some of the more common types of phenomena we study, and common techniques. However, the list will not be exhaustive by any means.

  12. Precursors to Interstellar Shocks of Solar Origin

    Science.gov (United States)

    Gurnett, D. A.; Kurth, W. S.; Stone, E. C.; Cummings, A. C.; Krimigis, S. M.; Decker, R. B.; Ness, N. F.; Burlaga, L. F.

    2015-12-01

    On or about 2012 August 25, the Voyager 1 spacecraft crossed the heliopause into the nearby interstellar plasma. In the nearly three years that the spacecraft has been in interstellar space, three notable particle and field disturbances have been observed, each apparently associated with a shock wave propagating outward from the Sun. Here, we present a detailed analysis of the third and most impressive of these disturbances, with brief comparisons to the two previous events, both of which have been previously reported. The shock responsible for the third event was first detected on 2014 February 17 by the onset of narrowband radio emissions from the approaching shock, followed on 2014 May 13 by the abrupt appearance of intense electron plasma oscillations generated by electrons streaming outward ahead of the shock. Finally, the shock arrived on 2014 August 25, as indicated by a jump in the magnetic field strength and the plasma density. Various disturbances in the intensity and anisotropy of galactic cosmic rays were also observed ahead of the shock, some of which are believed to be caused by the reflection and acceleration of cosmic rays by the magnetic field jump at the shock, and/or by interactions with upstream plasma waves. Comparisons to the two previous weaker events show somewhat similar precursor effects, although differing in certain details. Many of these effects are very similar to those observed in the region called the "foreshock" that occurs upstream of planetary bow shocks, only on a vastly larger spatial scale.

  13. Simplified Shock Design for Installation of Equipment

    Science.gov (United States)

    1982-03-01

    L.I. mb., Shock (mechanics), hardening, data processing, ,. arthquakes , failure (mechanics), shock spectra. 20 ABSTXT L:T T Con lln I aOnrovervs tild...Cambridge MA (Whitmian) NArL, ACADEMY OF ENG. ALEXAND)RIA. VA (SEARL.E. JR.)I NAT’URAL ENERGY LAB Library. Honolulu. III NEW MEXICO SOLAR ENERGY INST. Dr

  14. Oil price shocks and European industries

    NARCIS (Netherlands)

    Scholtens, Bert; Yurtsever, Cenk

    We investigate the impact of oil price shocks at the industry level in the Euro area for the period 1983-2007. We use different oil price specifications and use dynamic VAR models and multivariate regression to investigate how 38 different industries respond to oil price shocks. We pay specific

  15. Benjamin Franklin and Shock-Induced Amnesia

    Science.gov (United States)

    Finger, Stanley; Zaromb, Franklin

    2006-01-01

    Shock-induced amnesia received considerable attention after Cerletti popularized electroconvulsive shock therapy in the late 1930s. Yet, often overlooked is the fact that Benjamin Franklin recognized that passing electricity through the head could affect memory for the traumatic event. Franklin described his findings on himself and others in…

  16. Persistence of shocks in an experimental macroeconomy

    NARCIS (Netherlands)

    Noussair, C.N.; Pfajfar, D.; Zsiros, J.; Duffy, J.

    2014-01-01

    We design experimental economies based on a New Keynesian Dynamic Stochastic General Equilibrium (DSGE) model. We apply shocks to tastes, productivity, and interest rate policy, and measure the persistence of these shocks. We find that, in a setting where goods are perfect substitutes, there is

  17. Shock wave therapy in wound healing.

    Science.gov (United States)

    Qureshi, Ali A; Ross, Kimberly M; Ogawa, Rei; Orgill, Dennis P

    2011-12-01

    Recently, shock wave therapy has been investigated as an adjuvant therapy in the treatment of acute and chronic wounds. There are several devices with focused and unfocused shock waves that have been administered to a heterogenous group of wounds. Encouraging preclinical and clinical studies suggest that shock wave therapy may promote wound healing with little or no adverse events, prompting investigations into the mechanism of action and additional clinical trials. The peer-reviewed literature within the past 10 years was studied using an evidence-based approach. Preclinical studies demonstrate that shock wave therapy affects cellular function and leads to the expression of several genes and elaboration of growth factors known to promote wound healing. Limited clinical trials are encouraging for the use of shock wave therapy in the treatment of acute and chronic wounds. Serious complications, including wound infections, bleeding, hematomas, seromas, and petechiae, have not been reported in the largest of these studies. Shock wave therapy is an intriguing physical modality that may play an important role as an adjuvant therapy in wound healing. To date, there is no consensus on which wounds are most likely to benefit from shock wave therapy and what the optimal power, degree of focus, and frequency or number of cycles should be. Well-designed preclinical and clinical studies are necessary to better understand shock wave therapy in wound healing.

  18. Septisk shock på intensivafdeling

    DEFF Research Database (Denmark)

    Perner, Anders; Carlsen, Sarah; Marcussen, Klaus

    2010-01-01

    Patients in septic shock have a 33-42% 30-day mortality, but characteristics and outcome have not been assessed in Danish intensive care units (ICUs).......Patients in septic shock have a 33-42% 30-day mortality, but characteristics and outcome have not been assessed in Danish intensive care units (ICUs)....

  19. Anaphylactic shock during hydatid cyst surgery

    Directory of Open Access Journals (Sweden)

    Mustapha Bensghir

    2012-01-01

    Full Text Available Intraoperative anaphylactic shock is an unusual complication. Different causes can be involved. Surgery of hydatid cyst is rarely responsible. About a case report of anaphylactic shock due to hydatid cyst surgery, the authors discuss the mechanisms, principles of treatment, and prevention measures of this complication.

  20. Ion distributions upstream of an interplanetary shock

    Science.gov (United States)

    Kajdic, Primoz; Hietala, Heli; Blanco-Cano, Xochitl

    2017-04-01

    It is well known that supercritical collisionless shocks in the interplanetary (IP) space reflect part of the incoming particles (ions, electrons) in order to dissipate the kinetic energy of the upstream solar wind flow. When the conditions are right the reflected particles can escape far upstream from the shock. Their interaction with incoming ions and electrons results in the formation of the foreshock region which is populated by ultra-low frequency magnetic field fluctuations and different populations of reflected ions. Our knowledge on the latter comes mostly from observations of our planet's foreshock. However, the bow shock of the Earth typically has high Mach numbers, and the relatively small global curvature radius of the shock's shape affects the ion distribution characteristics. Interplanetary (IP) shocks, on the other hand, typically have lower Mach numbers and larger global curvature radii. In the past the majority of observed ion distributions detected upstream of IP shocks were diffuse. In only a couple of works the field-aligned ion beams were reported and even then the details of the ion distributions functions could not be determined. Here we present the first study showing clear observations of different types of ion distributions upstream of an interplanetary shock. The shock was observed on 8 October 2013 by several spacecraft, namely Wind, ACE, and the two ARTEMIS spacecraft P1 and P2. By using combined data from the Electrostatic Analyzer and the Solid State Telescope instruments onboard both ARTEMIS spacecraft we observed different types of ion distributions upstream of the shock: The distributions changed from field-aligned ion beams that were detected farthest from the shock, to intermediate and then to almost diffuse ion distributions near the shock transition. Furthermore, the observations at P1 and P2 locations also show spatial variability of the foreshock and the IP shock. The angle between the local shock normal and the upstream

  1. Coeficientes de digestibilidad total y de proteínas en alimentos experimentales para juveniles de Oplegnathus insignis (Kner, 1867 (Perciformes, Oplegnathidae

    Directory of Open Access Journals (Sweden)

    Avelino Muñoz

    2015-05-01

    Full Text Available Los alimentos para peces están formulados con diversos ingredientes, donde la harina de pescado es la principal fuente de proteína. Sin embargo, este insumo tiene un alto costo que lleva a la necesidad de evaluar nuevas fuentes de proteínas y probarlas en especies marinas. Oplegnathus insignis (San Pedro, Pacific beakfish es una especie omnívora en su etapa intermareal y carnívora en su etapa submareal, que ha sido cultivada de manera experimental, siendo necesario incorporar dietas formuladas. Este estudio reporta la experiencia en alimentación y nutrición, de juveniles de O. insignis alimentados con dietas formuladas con distintas fuentes de proteína. Se efectuó una experiencia con juveniles de O. insignis provenientes de un cultivo experimental. Se formularon cuatro alimentos, uno en base de harina de pescado (referencia y tres modificando la fuente de proteína del alimento de referencia, intercambiando un 30% de harina de pescado, por harina de soya, harina de moluscos y harina de quinoa. Se experimentó con 180 ind de 295,6 g y de 450 días post-eclosión, distribuidos en 12 estanques rectangulares de 1,6 m³. La alimentación fue a saciedad. Se efectuaron análisis próximales de los alimentos experimentales de las heces colectadas. Se determinó los coeficientes de digestibilidad total y proteína. El alimento con mayor contenido de proteína fue el que contenía harina de moluscos. El mayor coeficiente de digestibilidad total lo tienen los alimentos con harina de pescado (68,0% y harina de moluscos (67,1%, mientras que en los alimentos en base a harinas vegetales, la digestibilidad total para la harina de soya fue de 62,7% y para harina de quinoa de 64,1%. Estos resultados indican que es factible reemplazar un 30% de la harina de pescado por harinas de origen vegetal.

  2. Hypersonic Experimental and Computational Capability, Improvement and Validation. Volume 2. (l’Hypersonique experimentale et de calcul - capacite, ameliorafion et validation)

    Science.gov (United States)

    1998-12-01

    and K. Friedrichs . Supersonic Flow and Shock Waves. Springer-Verlag, New York, 1948. A Conical Flow Figure 113: Spherical polar coordinates...flux-split, Gauss -Seidel relaxation nu- merical technique. A five species air model is used (N2, 02, N, O, NO) in the solutions. The computational...Flow Over Spheres", J Fluid Mech 199; 389-405 (1995). 43 Kastell, D., Carl , M., and Eitelberg, G. "Phase Step Holographic Interferometry

  3. Barrier experiment: Shock initiation under complex loading

    Energy Technology Data Exchange (ETDEWEB)

    Menikoff, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-01-12

    The barrier experiments are a variant of the gap test; a detonation wave in a donor HE impacts a barrier and drives a shock wave into an acceptor HE. The question we ask is: What is the trade-off between the barrier material and threshold barrier thickness to prevent the acceptor from detonating. This can be viewed from the perspective of shock initiation of the acceptor subject to a complex pressure drive condition. Here we consider key factors which affect whether or not the acceptor undergoes a shock-to-detonation transition. These include the following: shock impedance matches for the donor detonation wave into the barrier and then the barrier shock into the acceptor, the pressure gradient behind the donor detonation wave, and the curvature of detonation front in the donor. Numerical simulations are used to illustrate how these factors affect the reaction in the acceptor.

  4. Organic synthesis in experimental impact shocks

    Science.gov (United States)

    McKay, C. P.; Borucki, W. J.

    1997-01-01

    Laboratory simulations of shocks created with a high-energy laser demonstrate that the efficacy of organic production depends on the molecular, not just the elemental composition of the shocked gas. In a methane-rich mixture that simulates a low-temperature equilibrium mixture of cometary material, hydrogen cyanide and acetylene were produced with yields of 5 x 10(17) molecules per joule. Repeated shocking of the methane-rich mixture produced amine groups, suggesting the possible synthesis of amino acids. No organic molecules were produced in a carbon dioxide-rich mixture, which is at odds with thermodynamic equilibrium approaches to shock chemistry and has implications for the modeling of shock-produced organic molecules on early Earth.

  5. Control groups in recent septic shock trials

    DEFF Research Database (Denmark)

    Pettilä, Ville; Hjortrup, Peter B; Jakob, Stephan M

    2016-01-01

    PURPOSE: The interpretation of septic shock trial data is profoundly affected by patients, control intervention, co-interventions and selected outcome measures. We evaluated the reporting of control groups in recent septic shock trials. METHODS: We searched for original articles presenting...... randomized clinical trials (RCTs) in adult septic shock patients from 2006 to 2016. We included RCTs focusing on septic shock patients with at least two parallel groups and at least 50 patients in the control group. We selected and evaluated data items regarding patients, control group characteristics...... % the proportion of patients with elevated lactate values. Five studies (21 %) provided data to estimate the proportion of septic shock patients fulfilling the Sepsis-3 definition. The mean data completeness score was 19 out of 36 (range 8-32). Of 18 predefined control group characteristics, a mean of 8 (range 2...

  6. 28th International Symposium on Shock Waves

    CERN Document Server

    2012-01-01

    The University of Manchester hosted the 28th International Symposium on Shock Waves between 17 and 22 July 2011. The International Symposium on Shock Waves first took place in 1957 in Boston and has since become an internationally acclaimed series of meetings for the wider Shock Wave Community. The ISSW28 focused on the following areas: Blast Waves, Chemically Reacting Flows, Dense Gases and Rarefied Flows, Detonation and Combustion, Diagnostics, Facilities, Flow Visualisation, Hypersonic Flow, Ignition, Impact and Compaction, Multiphase Flow, Nozzle Flow, Numerical Methods, Propulsion, Richtmyer-Meshkov, Shockwave Boundary Layer Interaction, Shock Propagation and Reflection, Shock Vortex Interaction, Shockwave Phenomena and Applications, as well as Medical and Biological Applications. The two Volumes contain the papers presented at the symposium and serve as a reference for the participants of the ISSW 28 and individuals interested in these fields.

  7. Converging shocks for DSD modelling

    Science.gov (United States)

    Matignon, Christophe

    2013-06-01

    Modelling of pyrotechnic systems requires both, a good understanding and precise prediction capabilities of the dynamics of detonation. When using insensitive high explosives IHE (such as TATB-based explosives) the interaction of the detonation front with the confinement can lead to very different detonation velocities. One of the most popular engineering tools used to model this behaviour is the Detonation Shock Dynamics (DSD). In the DSD assumption, the detonation front propagates at a normal shock velocity (Dn) which depends only on its local curvature (κ). For divergent detonations, the DSD limit is very well established both experimentally and theoretically and one can easily propose a model (which obeys the 1D quasi-steady weakly curved detonation theory) to reproduce this behavior. We propose to extend the DSD theory to slightly convergent detonation fronts and to validate it against experimental data. Two series of experiments were carried out. The first series was designed to collect precise information regarding converging detonation. Usually, in such configurations, the detonation is non steady, making precise and simultaneous measurements of velocity and curvature difficult to achieve. The originality of the proposed setup is to drive a self similar convergent detonation at constant speed in an IHE rod by an external explosive tube of greater detonation velocity (allowing an accurate recording of both velocity and curvature). A wide range EOS/reaction rate model (inspired from previous works of Wescott et al.) was then calibrated to reproduce both the strong shock initiation and the newly extended (Dn- κ) law. This model can be used to perform either direct numerical simulation (DNS) on fine resolved mesh grid, or its reduced PZR model (DSD based) on a much coarser grid. This model was then successfully validated against the second series of experiments involving a detonation propagating around an obstacle and exhibiting a non steady converging front

  8. Molecular shock response of explosives: electronic absorption spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Mcgrne, Shawn D [Los Alamos National Laboratory; Moore, David S [Los Alamos National Laboratory; Whitley, Von H [Los Alamos National Laboratory; Bolme, Cindy A [Los Alamos National Laboratory; Eakins, Daniel E [Los Alamos National Laboratory

    2009-01-01

    Electronic absorption spectroscopy in the range 400-800 nm was coupled to ultrafast laser generated shocks to begin addressing the question of the extent to which electronic excitations are involved in shock induced reactions. Data are presented on shocked polymethylmethacrylate (PMMA) thin films and single crystal pentaerythritol tetranitrate (PETN). Shocked PMMA exhibited thin film interference effects from the shock front. Shocked PETN exhibited interference from the shock front as well as broadband increased absorption. Relation to shock initiation hypotheses and the need for time dependent absorption data (future experiments) is briefly discussed.

  9. Laser Light Scattering by Shock Waves

    Science.gov (United States)

    Panda, J.; Adamovsky, G.

    1995-01-01

    Scattering of coherent light as it propagates parallel to a shock wave, formed in front of a bluff cylindrical body placed in a supersonic stream, is studied experimentally and numerically. Two incident optical fields are considered. First, a large diameter collimated beam is allowed to pass through the shock containing flow. The light intensity distribution in the resultant shadowgraph image, measured by a low light CCD camera, shows well-defined fringes upstream and downstream of the shadow cast by the shock. In the second situation, a narrow laser beam is brought to a grazing incidence on the shock and the scattered light, which appears as a diverging sheet from the point of interaction, is visualized and measured on a screen placed normal to the laser path. Experiments are conducted on shocks formed at various free-stream Mach numbers, M, and total pressures, P(sub 0). It is found that the widths of the shock shadows in a shadowgraph image become independent of M and P(sub 0) when plotted against the jump in the refractive index, (Delta)n, created across the shock. The total scattered light measured from the narrow laser beam and shock interaction also follows the same trend. In the numerical part of the study, the shock is assumed to be a 'phase object', which introduces phase difference between the upstream and downstream propagating parts of the light disturbances. For a given shape and (Delta)n of the bow shock the phase and amplitude modulations are first calculated by ray tracing. The wave front is then propagated to the screen using the Fresnet diffraction equation. The calculated intensity distribution, for both of the incident optical fields, shows good agreement with the experimental data.

  10. EFECTO DE LA CANTIDAD DE REPETICIONES MENTALES DIRIGIDAS DE LA TAREA SOBRE EL RENDIMIENTO DE UNA RUTINA OBLIGATORIA DE PISO EN NIÓAS QUE PRACTICAN GIMNASIA

    Directory of Open Access Journals (Sweden)

    Laura Sobalvarro Chavarría

    2001-12-01

    Full Text Available El propósito de esta investigación fue comparar dos cargas diferentes de práctica mental, una en que se realizaba dos repeticiones mentales de una rutina de piso y otra en la cual se hacía cinco repeticiones, para observar su efecto sobre el rendimiento en la ejecución de una rutina de piso en gimnasia. Participaron 18 niñas con edades entre cinco y doce años quienes practicaban gimnasia regularmente tres veces por semana desde al menos seis meses antes del estudio y que entrenaban para alcanzar los niveles III y IV de la USAG. Estas niñas se dividieron en dos grupos experimentales y un grupo control. El tratamiento de los grupos experimentales consistió en ver el video de la rutina, hacer práctica mental según el protocolo que les correspondía, practicar la rutina y ser evaluadas. Esto en cada sesión, para un total de 10 sesiones, que se desarrollaron tres veces por semana. El grupo control en cambio no realizó práctica mental ni física de la rutina solo veía el video, hacía una vez la rutina y era evaluado, pero esto fue solo en tres ocasiones (sesiones 1, 6 y 10; el resto del tiempo continuó con sus entrenamientos habituales. Dentro de los instrumentos de medición utilizados están el protocolo técnico de la rutina de piso y el protocolo de entrenamiento mental. Los resultados del ANOVA de dos vías (Grupos experimentales por 10 mediciones demostraron que al considerar las 10 mediciones se observa que el grupo experimental dos obtuvo un rendimiento significativamente mayor que el grupo experimental uno, (F:28.10, p<0.05 y en ambos grupos los mejores niveles de rendimiento se observan de la quinta a la sétima sesión, (F:23.86, p<0.05. Los resultados del ANOVA de dos vías (Grupo control y experimentales en tres mediciones repetidas demostraron que a lo largo de las mediciones, el grupo control no tuvo cambios significativos a diferencia de los experimentales, que mostraron un mejor rendimiento en la sexta y d

  11. Study of thermal shock wave in shock-compressed He II induced by gas dynamic shock wave impingement

    Science.gov (United States)

    Yang, H. S.; Ueta, Y.; Nagai, H.; Murakami, M.; Yanaka, K.

    2002-05-01

    Strong thermal shock waves induced by the impingement of a gas dynamic shock wave onto a He II free surface in the superfluid shock tube facility were investigated by measuring temperature variation with superconductive temperature sensors and by Schlieren visualization method with an ultra high-speed video camera (40,500 pictures/sec). The heat transfer from shock-compressed high temperature vapor to He II forming a thermal shock wave is considered. The temperature rise ratio of an induced thermal shock to that of an incident gas dynamic shock wave was found to be very small, as small as 0.003 at 1.80 K. It is seen that the most part of the heat do not be transmitted into bulk He II because a high density quantized vortex layer is rapidly developed in a thermal boundary layer in the immediate vicinity of the vapor-He II interface. The existence of a thermal boundary layer with a large temperature gradient in which the physical state varies from supercritical helium to He II temperature and the rapid growth up to about 1 mm in thickness of the layer with such as thermal conduction process are measured with the temperature measurements. Besides, it is also found that high compressibility of He II results in formation of a dark zone near the interface region that is extended toward bulk He II.

  12. Thermal shock resistance ceramic insulator

    Science.gov (United States)

    Morgan, Chester S.; Johnson, William R.

    1980-01-01

    Thermal shock resistant cermet insulators containing 0.1-20 volume % metal present as a dispersed phase. The insulators are prepared by a process comprising the steps of (a) providing a first solid phase mixture of a ceramic powder and a metal precursor; (b) heating the first solid phase mixture above the minimum decomposition temperature of the metal precursor for no longer than 30 minutes and to a temperature sufficiently above the decomposition temperature to cause the selective decomposition of the metal precursor to the metal to provide a second solid phase mixture comprising particles of ceramic having discrete metal particles adhering to their surfaces, said metal particles having a mean diameter no more than 1/2 the mean diameter of the ceramic particles, and (c) densifying the second solid phase mixture to provide a cermet insulator having 0.1-20 volume % metal present as a dispersed phase.

  13. Sobre la muerte voluntaria

    Directory of Open Access Journals (Sweden)

    Juan Álvarez-Cienfuegos Fidalgo

    2012-03-01

    Full Text Available El problema de cómo morir en nuestra sociedad se ha convertido en una inquietud para los ciudadanos y la reflexión moral. Especialmcnte por dos razones: por el desarrollo de la tecnología médica y por el hecho de que la mayor parte de los fallecimientos tienen lugar fuera del hogar, donde tradicionalmente ocurra el deceso. El presente artículo tiene como objetivo acercarse a esta cuestión. Para ello, se parte de la autonomía del ciudadano, con derecho a decidir sobre lo que considera cuál sea su manera de vivir y de morir. A tal fin, se hace una breve introducción sobre el dolor, el suicidio y la muerte, desde un punto de vista antropológico, pasando, después, a mostrar las cuestiones relacionadas con el problema de la eutanasia, donde la atención se dirigirá, ante todo, al enjuiciamiento crítico del tenso equilibrio en el que se mantienen dos principios fundamentales de la bioética: el de no maleficencia y el de autonomía del ciudadano.The problem of how to die in modern society has become a concern for both the citizen and moral reflection for two reasons in particular: due to developments in medical technology, and because most deaths occur outside the honre, where they traditionaÍlY took place. This paper addresses this issue, starting from citizen autonomy, the right to decide on what s/he considers to be his or her way of living and dying. To this end, a brief introduction considers pain, suicide and death from an anthropological viewpoint. Questions related to the problem of euthanasia are then exposed, with particular attention to, above all the critical judgement of the tense balance in which two fundamental principies of bioethics are held, the principle of non-maleficence and that of citizen autonomy.

  14. Determination experimentale des principales caracteristiques ...

    African Journals Online (AJOL)

    Il s'agit de la masse volumique basale, des taux de retraits totaux linéaire et volumique, du module d'Young dans la direction du fil du bois en flexion quatre points ainsi que la contrainte de rupture en traction simple, en compression simple, au cisaillement simple et enflexion quatre points. Borassus aethiopum is a palm ...

  15. Puente sobre el Maracaibo

    Directory of Open Access Journals (Sweden)

    Equipo Editorial

    2017-05-01

    Full Text Available Para salvar el lago de Maracaibo (Venezuela, el conocido ingeniero italiano Riccaido Morandi ha presentado un proyecto de puente para ferrocarril y carretera, de hormigón pretensado, de tramos independientes, constituyendo un sistema Gerber, que tiene una longitud total de 8.720 m y un vano central de 400 m de luz. Este último tramo, en unión de los dos adyacentes al mismo, constituirán, una vez terminada la obra, un conjunto continuo. El tablero del puente se halla a una altura de 45 m sobre el nivel del agua en la zona del canal, con objeto de permitir la navegación. El tablero, de 20,90 m de anchura total, se ha subdividido en tres partes, dos simétricas respecto al eje, laterales, de 7,20 m de anchura, para la circulación en sentidos opuestos por carretera, una plataforma central, de 5 m de ancho, para el ferrocarril y dos andenes para el paso de peatones y servicios.

  16. Refletindo sobre idosos institucionalizado

    Directory of Open Access Journals (Sweden)

    Cenir Gonçalves Tier

    2004-06-01

    Full Text Available Trata-se de uma pesquisa qualitativa, descritiva que teve por objetivo identificar como vem sendo o relacionamento idoso-família, identificando os motivos que levaram os familiares a optarem pela institucionalização do seu idoso, obtendo-se também a visão da família sobre o cuidado no lar. Para coleta dos dados utilizou-se um instrumento com perguntas abertas. A coleta dos dados efetivou-se nos meses de agosto de 2002 a julho de 2003, sendo sujeitos da pesquisa, familiares de idosos de uma instituição asilar em um município da região noroeste do Rio Grande do Sul. Através da análise de conteúdo constatou-se que a maior dificuldade encontrada pela família, visando dispensar cuidados ao idoso é a "falta de tempo para cuidar" do seu familiar idoso, pois a maioria deles exige cuidados em tempo integral.

  17. Debate internacional sobre pobreza

    Directory of Open Access Journals (Sweden)

    Neritza Alvarado Chacín

    2016-01-01

    Full Text Available El objetivo del artículo es organizar la proliferación de ideas en torno de la pobreza, a menudo dispersas, difusas y confusas en la literatura, bosquejando sistematizadamente un marco teórico referencial útil al abordaje científico de este fenómeno, en investigaciones teóricas y aplicadas, así como en la enseñanza y discusión de tales temas en el ámbito universitario. Para ello, se compendian, organizan y clasifican diversos enfoques sobre la pobreza, según los criterios presentes en los planteamientos de autores e instituciones relevantes que han contribuido a la reflexión desde distintas lecturas, teniendo en cuenta que no existe consenso en torno a una definición. La investigación es exploratoria-documental. Se aplican las técnicas del arqueo electrónico y físico de la información, el fichaje computarizado y la reducción de la misma en tablas de contenido. Se precisa el alcance de las mismas en el tiempo, según la evolución conceptual que han experimentado en el debate internacional. Se señalan algunas ventajas y desventajas de los principales enfoques, que han sido reconocidas en el mismo debate.

  18. Sobre el nombre "Quechua"

    Directory of Open Access Journals (Sweden)

    Rodolfo Cerrón-Palomino

    1985-06-01

    Full Text Available Uno de los primeros problemas con el que a menudo tropiezael estudioso de los idiomas ágrafos, como es el caso de las lenguasaborígenes de América, es el de su denominación (glotónimo.En la medida ,en que, por razones históricas, las noticias sobretales lenguas, y por consiguiente los primeros estudios sobre lasmismas, surgen a partir del contacto con los miembros de la civilización occidental, los nombres de los distintos idiomas, así comode los grupos étnicos que los manejan, son el resultado casi siempre arbitrario cie designaciones fortuitas hechas por viajeros, misiioneros y exploradores, quienes por lo general se basan, para ello, bien en descripciones físicas de los grupo étnicos, en ciertos indios geográficos que constituyen el habitat de los mismos, e incluso en prejuicios que se nutren de un marcado europocentrismo.

  19. A Prognostic Model for Development of Profound Shock among Children Presenting with Dengue Shock Syndrome.

    Directory of Open Access Journals (Sweden)

    Phung Khanh Lam

    Full Text Available To identify risk factors and develop a prediction model for the development of profound and recurrent shock amongst children presenting with dengue shock syndrome (DSS.We analyzed data from a prospective cohort of children with DSS recruited at the Paediatric Intensive Care Unit of the Hospital for Tropical Disease in Ho Chi Minh City, Vietnam. The primary endpoint was "profound DSS", defined as ≥2 recurrent shock episodes (for subjects presenting in compensated shock, or ≥1 recurrent shock episodes (for subjects presenting initially with decompensated/hypotensive shock, and/or requirement for inotropic support. Recurrent shock was evaluated as a secondary endpoint. Risk factors were pre-defined clinical and laboratory variables collected at the time of presentation with shock. Prognostic model development was based on logistic regression and compared to several alternative approaches.The analysis population included 1207 children of whom 222 (18% progressed to "profound DSS" and 433 (36% had recurrent shock. Independent risk factors for both endpoints included younger age, earlier presentation, higher pulse rate, higher temperature, higher haematocrit and, for females, worse hemodynamic status at presentation. The final prognostic model for "profound DSS" showed acceptable discrimination (AUC=0.69 for internal validation and calibration and is presented as a simple score-chart.Several risk factors for development of profound or recurrent shock among children presenting with DSS were identified. The score-chart derived from the prognostic models should improve triage and management of children presenting with DSS in dengue-endemic areas.

  20. Hemodynamic Analysis of Pediatric Septic Shock and Cardiogenic Shock Using Transpulmonary Thermodilution.

    Science.gov (United States)

    Lee, En-Pei; Hsia, Shao-Hsuan; Lin, Jainn-Jim; Chan, Oi-Wa; Lee, Jung; Lin, Chia-Ying; Wu, Han-Ping

    2017-01-01

    Septic shock and cardiogenic shock are the two most common types of shock in children admitted to pediatric intensive care units (PICUs). The aim of the study was to investigate which hemodynamic variables were associated with mortality in children with shock. We retrospectively analyzed 50 children with shock (37 septic shock cases and 13 cardiogenic shock cases) in the PICU and monitored their hemodynamics using transpulmonary thermodilution from 2003 to 2016. Clinical factors were analyzed between the patients with septic and cardiogenic shock. In addition, hemodynamic parameters associated with mortality were analyzed. The 28-day mortality was significantly higher in the septic group than in the cardiogenic group (p = 0.016). Initially, the parameters of cardiac output and cardiac contractility were higher in the septic group (p shock at the time of initial admission and after the first 24 hours (both p shock (p < 0.001). Therefore, during the first 24 hours after intensive care, SVRI and cardiac index are the most important hemodynamic parameters associated with mortality.

  1. Shock Mechanism Analysis and Simulation of High-Power Hydraulic Shock Wave Simulator

    Directory of Open Access Journals (Sweden)

    Xiaoqiu Xu

    2017-01-01

    Full Text Available The simulation of regular shock wave (e.g., half-sine can be achieved by the traditional rubber shock simulator, but the practical high-power shock wave characterized by steep prepeak and gentle postpeak is hard to be realized by the same. To tackle this disadvantage, a novel high-power hydraulic shock wave simulator based on the live firing muzzle shock principle was proposed in the current work. The influence of the typical shock characteristic parameters on the shock force wave was investigated via both theoretical deduction and software simulation. According to the obtained data compared with the results, in fact, it can be concluded that the developed hydraulic shock wave simulator can be applied to simulate the real condition of the shocking system. Further, the similarity evaluation of shock wave simulation was achieved based on the curvature distance, and the results stated that the simulation method was reasonable and the structural optimization based on software simulation is also beneficial to the increase of efficiency. Finally, the combination of theoretical analysis and simulation for the development of artillery recoil tester is a comprehensive approach in the design and structure optimization of the recoil system.

  2. Efectos del diacepam sobre la extincion consumatoria

    OpenAIRE

    Justel, Nadia; Mustaca, Alba Elisabeth; Bentosela, Mariana; Ruetti, Eliana Martha

    2017-01-01

    La frustración es la reacción emocional que se produce ante la disminución u omisión inesperada de un reforzador. Uno de los procedimientos experimentales utilizados para inducir frustración es la extinción consumatoria, en la cual las ratas reciben una solución azucarada al 32% durante 10 sesiones diarias y luego sorpresivamente no reciben la recompensa durante 3 sesiones. Los resultados obtenidos en el presente trabajo señalan que la administración de una benzodiacepina como el diacepam, in...

  3. Global Aeroheating Measurements of Shock-Shock Interactions on a Swept Cylinder

    Science.gov (United States)

    Mason, Michelle L.; Berry, Scott A.

    2015-01-01

    The effects of fin leading-edge radius and sweep angle on peak heating rates due to shock-shock interactions were investigated in the NASA Langley Research Center 20-Inch Mach 6 Air Tunnel. The cylindrical leading-edge fin models, with radii varied from 0.25 to 0.75 inches, represent wings or struts on hypersonic vehicles. A 9deg wedge generated a planar oblique shock at 16.7deg. to the flow that intersected the fin bow shock, producing a shock-shock interaction that impinged on the fin leading edge. The fin sweep angle was varied from 0deg (normal to the free-stream) to 15deg and 25deg swept forward. These cases were chosen to explore three characterized shock-shock interaction types. Global temperature data were obtained from the surface of the fused silica fins using phosphor thermography. Metal oil flow models with the same geometries as the fused silica models were used to visualize the streamline patterns for each angle of attack. High-speed zoom-schlieren videos were recorded to show the features and any temporal unsteadiness of the shock-shock interactions. The temperature data were analyzed using a one-dimensional semi-infinite method, as well as one- and two-dimensional finite-volume methods. These results were compared to determine the proper heat transfer analysis approach to minimize errors from lateral heat conduction due to the presence of strong surface temperature gradients induced by the shock interactions. The general trends in the leading-edge heat transfer behavior were similar for each explored shock-shock interaction type regardless of the leading-edge radius. However, the dimensional peak heat transfer coefficient augmentation increased with decreasing leading-edge radius. The dimensional peak heat transfer output from the two-dimensional code was about 20% higher than the value from a standard, semi-infinite one-dimensional method.

  4. Overview of shock waves in medicine

    Science.gov (United States)

    Cleveland, Robin O.

    2003-10-01

    A brief overview of three applications of shock waves is presented. Shock wave lithotripsy (SWL) has been in clinical use for more than 20 years. In the United States it is used to treat more than 80% of kidney stone cases and has wide acceptance with patients because it is a noninvasive procedure. Despite SWLs enormous success there is no agreement on how shock waves comminute stones. There is also a general acceptance that shock waves lead to trauma to the soft tissue of the kidney. Yet there has been little forward progress in developing lithotripters which provide comminution with less side-effects, indeed the original machine is still considered the gold standard. The last decade has seen the advent of new shock wave devices for treating principally musculoskeletal indications, such as plantar fasciitis, tennis elbow, and bone fractures that do not heal. This is referred to as shock wave therapy (SWT). The mechanisms by which SWT works are even less well understood than SWL and the consequences of bioeffects have also not been studied in detail. Shock waves have also been shown to be effective at enhancing drug delivery into cells and assisting with gene transfection. [Work partially supported by NIH.

  5. Genetics and genomics in pediatric septic shock.

    Science.gov (United States)

    Wong, Hector R

    2012-05-01

    Pediatric septic shock continues to be an important public health problem. Several investigative groups have applied genetic and genomic approaches as a means of identifying novel pathways and therapeutic targets, discovery of sepsis-related biomarkers, and identification of septic shock subclasses. This review will highlight studies in pediatric sepsis with a focus on gene association studies and genome-wide expression profiling. A summary of published literature involving gene association and expression profiling studies specifically involving pediatric sepsis and septic shock. Several polymorphisms of genes broadly involved in inflammation, immunity, and coagulation have been linked with susceptibility to sepsis, or outcome of sepsis in children. Many of these studies involve meningococcemia, and the strongest association involves a functional polymorphism of the plasminogen activator inhibitor-1 promoter region and meningococcal sepsis. Expression profiling studies in pediatric septic shock have identified zinc supplementation and inhibition of matrix metalloproteinase-8 activity as potential, novel therapeutic approaches in sepsis. Studies focused on discovery of sepsis-related biomarkers have identified interleukin-8 as a robust outcome biomarker in pediatric septic shock. Additional studies have demonstrated the feasibility and clinical relevance of gene expression-based subclassification of pediatric septic shock. Pediatric sepsis and septic shock are increasingly being studied by genetic and genomic approaches and the accumulating data hold the promise of enhancing our future approach to this ongoing clinical problem.

  6. Impaired Fracture Healing after Hemorrhagic Shock

    Directory of Open Access Journals (Sweden)

    Philipp Lichte

    2015-01-01

    Full Text Available Impaired fracture healing can occur in severely injured patients with hemorrhagic shock due to decreased soft tissue perfusion after trauma. We investigated the effects of fracture healing in a standardized pressure controlled hemorrhagic shock model in mice, to test the hypothesis that bleeding is relevant in the bone healing response. Male C57/BL6 mice were subjected to a closed femoral shaft fracture stabilized by intramedullary nailing. One group was additionally subjected to pressure controlled hemorrhagic shock (HS, mean arterial pressure (MAP of 35 mmHg for 90 minutes. Serum cytokines (IL-6, KC, MCP-1, and TNF-α were analyzed 6 hours after shock. Fracture healing was assessed 21 days after fracture. Hemorrhagic shock is associated with a significant increase in serum inflammatory cytokines in the early phase. Histologic analysis demonstrated a significantly decreased number of osteoclasts, a decrease in bone quality, and more cartilage islands after hemorrhagic shock. μCT analysis showed a trend towards decreased bone tissue mineral density in the HS group. Mechanical testing revealed no difference in tensile failure. Our results suggest a delay in fracture healing after hemorrhagic shock. This may be due to significantly diminished osteoclast recruitment. The exact mechanisms should be studied further, particularly during earlier stages of fracture healing.

  7. Energetics of the terrestrial bow shock

    Science.gov (United States)

    Hamrin, Maria; Gunell, Herbert; Norqvist, Patrik

    2017-04-01

    The solar wind is the primary energy source for the magnetospheric energy budget. Energy can enter through the magnetopause both as kinetic energy (plasma entering via e.g. magnetic reconnection and impulsive penetration) and as electromagnetic energy (e.g. by the conversion of solar wind kinetic energy into electromagnetic energy in magnetopause generators). However, energy is extracted from the solar wind already at the bow shock, before it encounters the terrestrial magnetopause. At the bow shock the supersonic solar wind is slowed down and heated, and the region near the bow shock is known to host many complex processes, including the accelerating of particles and the generation of waves. The processes at and near the bow shock can be discussed in terms of energetics: In a generator (load) process kinetic energy is converted to (from) electromagnetic energy. Bow shock regions where the solar wind is decelerated correspond to generators, while regions where particles are energized (accelerated and heated) correspond to loads. Recently, it has been suggested that currents from the bow shock generator should flow across the magnetosheath and connect to the magnetospause current systems [Siebert and Siscoe, 2002; Lopez et al., 2011]. In this study we use data from the Magnetospheric MultiScale (MMS) mission to investigate the energetics of the bow shock and the current closure, and we compare with the MHD simulations of Lopez et al., 2011.

  8. Cold Osmotic Shock in Saccharomyces cerevisiae

    Science.gov (United States)

    Patching, J. W.; Rose, A. H.

    1971-01-01

    Saccharomyces cerevisiae NCYC 366 is susceptible to cold osmotic shock. Exponentially growing cells from batch cultures grown in defined medium at 30 C, after being suspended in 0.8 m mannitol containing 10 mm ethylenedia-minetetraacetic acid and then resuspended in ice-cold 0.5 mm MgCl2, accumulated the nonmetabolizable solutes d-glucosamine-hydrochloride and 2-aminoisobutyrate at slower rates than unshocked cells; shocked cells retained their viability. Storage of unshocked batch-grown cells in buffer at 10 C led to an increase in ability to accumulate glucosamine, and further experiments were confined to cells grown in a chemostat under conditions of glucose limitation, thereby obviating the need for storing cells before use. A study was made of the effect of the different stages in the cold osmotic shock procedure, including the osmotic stress, the chelating agent, and the cold Mg2+-containing diluent, on viability and solute-accumulating ability. Growth of shocked cells in defined medium resembled that of unshocked cells; however, in malt extract-yeast extract-glucose-peptone medium, the shocked cells had a longer lag phase of growth and initially grew at a slower rate. Cold osmotic shock caused the release of low-molecular-weight compounds and about 6 to 8% of the cell protein. Neither the cell envelope enzymes, invertase, acid phosphatase and l-leucine-β-naphthylamidase, nor the cytoplasmic enzyme, alkaline phosphatase, were released when yeast cells were subjected to cold osmotic shock. PMID:5001201

  9. Simulation of a Shock Recovery Experiment

    Science.gov (United States)

    Vignjevic, R.; Bourne, N. K.; Hughes, K.; Stojkovic, M.

    2007-12-01

    It is difficult to obtain experimental data for the behaviour of material under shock loading due to the dynamic nature of this process and the finite time available during which measurements can be taken. As a result the shock recovery technique was been developed to allow recovery of material after a single shock-release loading. The main goal of this experimental technique is to examine material properties after a single, well-defined shock wave followed by a single release wave have been introduced. The process should be such that any change found in the sample after recovery can be attributed to the shock process alone, the geometry and design of the target and the fixture play an important role in achieving this. In this work a shock recovery experimental configuration is proposed from simulations performed using the Lagrangian hydrocode DYNA. The investigation of the shock wave in the simulation entails examining the time histories for a single element, or block of elements of interest. A new design is developed with improved performance.

  10. Shock waves from nonspherical cavitation bubbles

    Science.gov (United States)

    Supponen, Outi; Obreschkow, Danail; Kobel, Philippe; Tinguely, Marc; Dorsaz, Nicolas; Farhat, Mohamed

    2017-09-01

    We present detailed observations of the shock waves emitted at the collapse of single cavitation bubbles using simultaneous time-resolved shadowgraphy and hydrophone pressure measurements. The geometry of the bubbles is systematically varied from spherical to very nonspherical by decreasing their distance to a free or rigid surface or by modulating the gravity-induced pressure gradient aboard parabolic flights. The nonspherical collapse produces multiple shocks that are clearly associated with different processes, such as the jet impact and the individual collapses of the distinct bubble segments. For bubbles collapsing near a free surface, the energy and timing of each shock are measured separately as a function of the anisotropy parameter ζ , which represents the dimensionless equivalent of the Kelvin impulse. For a given source of bubble deformation (free surface, rigid surface, or gravity), the normalized shock energy depends only on ζ , irrespective of the bubble radius R0 and driving pressure Δ p . Based on this finding, we develop a predictive framework for the peak pressure and energy of shock waves from nonspherical bubble collapses. Combining statistical analysis of the experimental data with theoretical derivations, we find that the shock peak pressures can be estimated as jet impact-induced hammer pressures, expressed as ph=0.45 (ρc2Δ p ) 1 /2ζ-1 at ζ >10-3 . The same approach is found to explain the shock energy decreasing as a function of ζ-2 /3.

  11. Vibration analysis on compact car shock absorber

    Science.gov (United States)

    Tan, W. H.; Cheah, J. X.; Lam, C. K.; Lim, E. A.; Chuah, H. G.; Khor, C. Y.

    2017-10-01

    Shock absorber is a part of the suspension system which provides comfort experience while driving. Resonance, a phenomenon where forced frequency is coinciding with the natural frequency has significant effect on the shock absorber itself. Thus, in this study, natural frequencies of the shock absorber in a 2 degree-of-freedom system were investigated using Wolfram Mathematica 11, CATIA, and ANSYS. Both theoretical and simulation study how will the resonance affect the car shock absorber. The parametric study on the performance of shock absorber also had been conducted. It is found that the failure tends to occur on coil sprung of the shock absorber before the body of the shock absorber is fail. From mathematical modelling, it can also be seen that higher vibration level occurred on un-sprung mass compare to spring mass. This is due to the weight of sprung mass which could stabilize as compared with the weight of un-sprung mass. Besides that, two natural frequencies had been obtained which are 1.0 Hz and 9.1 Hz for sprung mass and un-sprung mass respectively where the acceleration is recorded as maximum. In conclusion, ANSYS can be used to validate with theoretical results with complete model in order to match with mathematical modelling.

  12. Whistler waves at the Earth bow shock

    Science.gov (United States)

    Wei, Hanying; Russell, Christopher T.; Strangeway, Rorbert J.; Schwartz, Steve J.; An, Xin; Fischer, David; Le Contel, Olivier; Argall, Matthew; Paterson, William R.; Torbert, Roy B.

    2017-04-01

    The Magnetospheric Multiscale (MMS) spacecraft, with their state-of-the-art plasma and field instruments onboard, allow us to investigate electromagnetic waves at the bow shock and their association with small-scale disturbances in the shocked plasmas. Understanding these waves could improve our knowledge on the heating of electrons and ions across the shock ramp and the energy dissipation of supercritical shocks. We have found broad-band and narrow band waves across the shock ramp and slightly downstream. The broad-band waves propagate obliquely to the magnetic field direction and have frequencies up to the electron cyclotron frequency. Simultaneously, the electrons have quite disturbed velocities and are anisotropic in velocity space, leading to multiple possible instabilities, such as kinetic cross-field streaming instability, low-hybrid drift instability, etc. In the same region with the broad-band wave, there are narrow-band waves at a few hundred Hertz with durations under a second. These waves are right-handed circularly polarized and propagate along the magnetic field lines. The broad-band waves are only observed at the shock ramp, but the narrow-band waves are observed more frequently further downstream in the magnetosheath. Both wave types are likely to be whistler mode with different generation mechanisms. In this paper, we examine the electric and magnetic fields of these waves, as well as the plasma observations to understand the wave generation and their effects on the shock and magnetosheath plasmas.

  13. Modeling nonthermal emission from stellar bow shocks

    Science.gov (United States)

    Pereira, V.; López-Santiago, J.; Miceli, M.; Bonito, R.; de Castro, E.

    2016-04-01

    Context. Runaway O- and early B-type stars passing through the interstellar medium at supersonic velocities and characterized by strong stellar winds may produce bow shocks that can serve as particle acceleration sites. Previous theoretical models predict the production of high-energy photons by nonthermal radiative processes, but their efficiency is still debated. Aims: We aim to test and explain the possibility of emission from the bow shocks formed by runaway stars traveling through the interstellar medium by using previous theoretical models. Methods: We applied our model to AE Aurigae, the first reported star with an X-ray detected bow shock, to BD+43 3654, in which the observations failed in detecting high-energy emission, and to the transition phase of a supergiant star in the late stages of its life. Results: From our analysis, we confirm that the X-ray emission from the bow shock produced by AE Aurigae can be explained by inverse Compton processes involving the infrared photons of the heated dust. We also predict low high-energy flux emission from the bow shock produced by BD+43 3654, and the possibility of high-energy emission from the bow shock formed by a supergiant star during the transition phase from blue to red supergiant. Conclusions: Bow shocks formed by different types of runaway stars are revealed as a new possible source of high-energy photons in our neighborhood.

  14. Radiation from Shock-Accelerated Particles

    Science.gov (United States)

    Nishikawa, Ken-ichi; Choi, E. J.; Min, K. W.; Niemiec, J.; Zhang, B.; Hardee, P.; Mizuno, Y.; Medvedev, M.; Nordlund, A.; Frederiksen, J.; hide

    2012-01-01

    Plasma instabilities excited in collisionless shocks are responsible for particle acceleration, generation of magnetic fields , and associated radiation. We have investigated the particle acceleration and shock structure associated with an unmagnetized relativistic jet propagating into an unmagnetized plasma. Cold jet electrons are thermalized and slowed while the ambient electrons are swept up to create a partially developed hydrodynamic-like shock structure. The shock structure depends on the composition of the jet and ambient plasma (electron-positron or electron-ions). Strong electromagnetic fields are generated in the reverse , jet shock and provide an emission site. These magnetic fields contribute to the electron's transverse deflection behind the shock. We have calculated, self-consistently, the radiation from electrons accelerated in the turbulent magnetic fields. We found that the synthetic spectra depend on the Lorentz factor of the jet, its thermal temperature and strength of the generated magnetic fields. The detailed properties of the radiation are important for understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jet shocks, and supernova remnants

  15. Recognition of a Kawasaki Disease Shock Syndrome

    Science.gov (United States)

    Kanegaye, John T.; Wilder, Matthew S.; Molkara, Delaram; Frazer, Jeffrey R.; Pancheri, Joan; Tremoulet, Adriana H.; Watson, Virginia E.; Best, Brookie M.; Burns, Jane C.

    2010-01-01

    objective We sought to define the characteristics that distinguish Kawasaki disease shock syndrome from hemodynamically normal Kawasaki disease. methods We collected data prospectively for all patients with Kawasaki disease who were treated at a single institution during a 4-year period. We defined Kawasaki disease shock syndrome on the basis of systolic hypotension for age, a sustained decrease in systolic blood pressure from baseline of ≥20%, or clinical signs of poor perfusion. We compared clinical and laboratory features, coronary artery measurements, and responses to therapy and analyzed indices of ventricular systolic and diastolic function during acute and convalescent Kawasaki disease. results Of 187 consecutive patients with Kawasaki disease, 13 (7%) met the definition for Kawasaki disease shock syndrome. All received fluid resuscitation, and 7 (54%) required vasoactive infusions. Compared with patients without shock, patients with Kawasaki disease shock syndrome were more often female and had larger proportions of bands, higher C-reactive protein concentrations, and lower hemoglobin concentrations and platelet counts. Evidence of consumptive coagulopathy was common in the Kawasaki disease shock syndrome group. Patients with Kawasaki disease shock syndrome more often had impaired left ventricular systolic function (ejection fraction of <54%: 4 of 13 patients [31%] vs 2 of 86 patients [4%]), mitral regurgitation (5 of 13 patients [39%] vs 2 of 83 patients [2%]), coronary artery abnormalities (8 of 13 patients [62%] vs 20 of 86 patients [23%]), and intravenous immunoglobulin resistance (6 of 13 patients [46%] vs 32 of 174 patients [18%]). Impairment of ventricular relaxation and compliance persisted among patients with Kawasaki disease shock syndrome after the resolution of other hemodynamic disturbances. conclusions Kawasaki disease shock syndrome is associated with more-severe laboratory markers of inflammation and greater risk of coronary artery

  16. La casa sobre el monte

    OpenAIRE

    Valderrama, Kohnie; Martín Domínguez, Nicolás

    2016-01-01

    Reflexiones de la autora sobre su vida, su infancia, sus padres, que le llevan a mandar construir una casa en una parcela con encinas, integrada por completo en el entorno y utilizando el hormigón como material constructivo.

  17. Economic Shocks and Subjective Well-being

    DEFF Research Database (Denmark)

    Hariri, Jacob Gerner; Bjørnskov, Christian; Justesen, Mogens Kamp

    This paper examines how economic shocks affect individual well-being in developing countries. Using the case of a sudden and unanticipated currency devaluation in Botswana as a quasi-experiment, we examine how this monetary shock affects individuals’ evaluations of well-being. We do so by using......-treatment respondents, surveyed after the devaluation. Our estimates show that the devaluation had a large and significantly negative effect on individuals’ evaluations of subjective well-being. These results suggest that macroeconomic shocks, such as unanticipated currency devaluations, may have significant short......-term costs in the form of reductions in people’s sense of well-being....

  18. Economic Shocks and Subjective Well-Being

    DEFF Research Database (Denmark)

    Hariri, Jacob Gerner; Bjørnskov, Christian; Justesen, Mogens Kamp

    This paper examines how economic shocks affect individual well-being in developing countries. Using the case of a sudden and unanticipated currency devaluation in Botswana as a quasi-experiment, we examine how this monetary shock affects individuals’ evaluations of well-being. We do so by using......-treatment respondents, surveyed after the devaluation. Our estimates show that the devaluation had a large and significantly negative effect on individuals’ evaluations of subjective well-being. These results suggest that macroeconomic shocks, such as unanticipated currency devaluations, may have significant short......-term costs in the form of reductions in people’s sense of well-being....

  19. Best Practices for Unstructured Grid Shock Fitting

    Science.gov (United States)

    McCloud, Peter L.

    2017-01-01

    Unstructured grid solvers have well-known issues predicting surface heat fluxes when strong shocks are present. Various efforts have been made to address the underlying numerical issues that cause the erroneous predictions. The present work addresses some of the shortcomings of unstructured grid solvers, not by addressing the numerics, but by applying structured grid best practices to unstructured grids. A methodology for robust shock detection and shock fitting is outlined and applied to production relevant cases. Results achieved by using the Loci-CHEM Computational Fluid Dynamics solver are provided.

  20. Nonequilibrium volumetric response of shocked polymers

    Energy Technology Data Exchange (ETDEWEB)

    Clements, B E [Los Alamos National Laboratory

    2009-01-01

    Polymers are well known for their non-equilibrium deviatoric behavior. However, investigations involving both high rate shock experiments and equilibrium measured thermodynamic quantities remind us that the volumetric behavior also exhibits a non-equilibrium response. Experiments supporting the notion of a non-equilibrium volumetric behavior will be summarized. Following that discussion, a continuum-level theory is proposed that will account for both the equilibrium and non-equilibrium response. Upon finding agreement with experiment, the theory is used to study the relaxation of a shocked polymer back towards its shocked equilibrium state.

  1. Clinico-Pathological aspects of Shock

    Directory of Open Access Journals (Sweden)

    Kulkarni M.D.

    2009-08-01

    Full Text Available Shock can be defined as “a common grave medical emergency characterised basically by reduction in the effective circulating blood volume and blood pressure”. (Robbins or as “Disparity between the volume of blood and the volume capacity of the vascular system” which cause inability of body tissue to metabolise nutrients due to inadequate oxygen supply. Shock can be classified into: Primary and Secondary.Cardiogenic, Vasogenic, Hematogenic, Neurogenic and Electrocution. The therapy includes Blood, Plasma, Saline transfusion, antibiotic, antihistaminic, hyperimmune serum, vasoconstrictor according to the cause of the shock. [Vet. World 2009; 2(4.000: 163-165

  2. Economic Shocks and Subjective Well-Being

    DEFF Research Database (Denmark)

    Hariri, Jacob Gerner; Bjørnskov, Christian; Kamp Justesen, Mogens

    2015-01-01

    This paper examines how economic shocks affect individual well-being in developing countries. Using the case of a sudden and unanticipated currency devaluation in Botswana as a quasi-experiment, we examine how this monetary shock affects individuals’ evaluations of well-being. We do so by using......-treatment respondents, surveyed after the devaluation. Our estimates show that the devaluation had a large and significantly negative effect on individuals’ evaluations of subjective well-being. These results suggest that macroeconomic shocks, such as unanticipated currency devaluations, may have significant short...

  3. Shocks in homogeneous and heterogeneous populations

    Energy Technology Data Exchange (ETDEWEB)

    Finkelstein, Maxim [Department of Mathematical Statistics, University of the Free State, PO Box 339, 9300 Bloemfontein (South Africa) and Max Planck Institute for Demographic Research, Rostock (Germany)]. E-mail: FinkelM.SCI@mail.uovs.ac.za

    2007-05-15

    A system subject to a point process of shocks is considered. Shocks occur in accordance with a non-homogeneous Poisson process. Different criterions of system failures are discussed in a homogeneous case. Two natural settings are analyzed. Heterogeneity is modeled by an unobserved univariate random variable (frailty). It is shown that reliability (safety) analysis for a heterogeneous case can differ dramatically from that for a homogeneous setting. A shock burn-in procedure for a heterogeneous population is described. The corresponding bounds for the failure rates are obtained.

  4. Shock-induced termination of reentrant cardiac arrhythmias: Comparing monophasic and biphasic shock protocols

    Science.gov (United States)

    Bragard, Jean; Simic, Ana; Elorza, Jorge; Grigoriev, Roman O.; Cherry, Elizabeth M.; Gilmour, Robert F.; Otani, Niels F.; Fenton, Flavio H.

    2013-12-01

    In this article, we compare quantitatively the efficiency of three different protocols commonly used in commercial defibrillators. These are based on monophasic and both symmetric and asymmetric biphasic shocks. A numerical one-dimensional model of cardiac tissue using the bidomain formulation is used in order to test the different protocols. In particular, we performed a total of 4.8 × 106 simulations by varying shock waveform, shock energy, initial conditions, and heterogeneity in internal electrical conductivity. Whenever the shock successfully removed the reentrant dynamics in the tissue, we classified the mechanism. The analysis of the numerical data shows that biphasic shocks are significantly more efficient (by about 25%) than the corresponding monophasic ones. We determine that the increase in efficiency of the biphasic shocks can be explained by the higher proportion of newly excited tissue through the mechanism of direct activation.

  5. Cardiogenic shock complicating acute myocardial infarction; prognostic impact of early and late shock development

    DEFF Research Database (Denmark)

    Lindholm, M G; Køber, L; Boesgaard, S

    2003-01-01

    AIMS: Cardiogenic shock accounts for the majority of deaths following acute myocardial infarction. The majority of outcome data on this issue are, however, derived from single hospitals, referral centers or selected patients in randomized studies. The purpose of this study was to investigate...... incidence, outcome and prognostic significance of cardiogenic shock in 6676 consecutive patients with acute myocardial infarction. METHODS AND RESULTS: Demographic and clinical data including the presence of cardiogenic shock were prospectively collected in 6676 non-invasively managed patients...... with myocardial infarction consecutively admitted to 27 different hospitals during a 2-year period. Six-year mortality data were collected in 99.9% of the population. Cardiogenic shock developed in 444 patients (6.7%). In 59% of these patients cardiogenic shock developed within 48 h, 11% developed shock during...

  6. Shock-induced termination of reentrant cardiac arrhythmias: Comparing monophasic and biphasic shock protocols

    Energy Technology Data Exchange (ETDEWEB)

    Bragard, Jean, E-mail: jbragard@unav.es; Simic, Ana; Elorza, Jorge [Department of Physics and Applied Math., University of Navarra, Pamplona (Spain); Grigoriev, Roman O.; Fenton, Flavio H. [School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Cherry, Elizabeth M. [School of Mathematical Sciences, Rochester Institute of Technology, Rochester, New York 14623 (United States); Gilmour, Robert F. [University of Prince Edward Island, Charlottetown C1A 4P3 (Canada); Otani, Niels F. [School of Mathematical Sciences, Rochester Institute of Technology, Rochester, New York 14623 (United States); Department of Biomedical Sciences, Cornell University, Ithaca, New York 14853 (United States)

    2013-12-15

    In this article, we compare quantitatively the efficiency of three different protocols commonly used in commercial defibrillators. These are based on monophasic and both symmetric and asymmetric biphasic shocks. A numerical one–dimensional model of cardiac tissue using the bidomain formulation is used in order to test the different protocols. In particular, we performed a total of 4.8 × 10{sup 6} simulations by varying shock waveform, shock energy, initial conditions, and heterogeneity in internal electrical conductivity. Whenever the shock successfully removed the reentrant dynamics in the tissue, we classified the mechanism. The analysis of the numerical data shows that biphasic shocks are significantly more efficient (by about 25%) than the corresponding monophasic ones. We determine that the increase in efficiency of the biphasic shocks can be explained by the higher proportion of newly excited tissue through the mechanism of direct activation.

  7. Development of a flyer design to perform plate impact shock-release-shock experiments on explosives

    Science.gov (United States)

    Finnegan, Simon; Ferguson, James; Millett, Jeremy; Goff, Michael

    2017-06-01

    A flyer design to generate a shock-release-shock loading history within a gas gun target was developed before being used to study the response of an HMX based explosive. The flyer consisted of two flyer plates separated by a vacuum gap. This created a rear free surface that, with correct material choice, allowed the target to release to close to ambient pressure between the initial shock and subsequent re-shock. The design was validated by impacting piezoelectric pin arrays to record the front flyer deformation. Shots were performed on PCTFE targets to record the shock states generated in an inert material prior to subjecting an HMX based explosive to the same loading. The response of the explosive to this loading history was recorded using magnetic particle velocity (PV) gauges embedded within the targets. The behavior during the run to detonation is compared with the response to sustained shocks at similar input pressures.

  8. Algunos apuntes sobre comunidad

    Directory of Open Access Journals (Sweden)

    Clara Pérez Cárdenas

    2000-08-01

    Full Text Available Comunidad es, entre los temas de estudio del curriculum de los residentes en Medicina General Integral, uno de aquellos en las que mayores dificultades encontramos para poderlo impartir, pues la bibliografía sobre el tema está un tanto dispersa. Es un aspecto que los propios residentes no evalúan con justeza; sin embargo es de sumo interés que como profesionales de la salud no obviemos que nuestro trabajo de promoción, prevención y tratamiento, debe darse a nivel de individuo, pero también en las familias y en la comunidad como un todo, y por lo tanto debamos incorporar, al menos, nociones de lo que es una comunidad y qué es participación comunitaria para tener idea de cómo fomentarla, única vía para que nuestras acciones de salud sean más efectivasCommunity is one of the most difficult subjects to be taught among those included in the curriculum of General Comprehensive Medicine residents, since bibliography on this topic is a bit dispersed. This aspect, which is not properly evaluated by residents, is very important for health professionals to do our work of promotion, prevention and treatment not only at the level of the individual, but also at the level of the family and of the community as a whole. Therefore, we need to have some notions about community and community participation to be able to promote them, as the only way to make our health actions more effective

  9. Oxidación de propileno sobre catalizadores Pt-Cu/y-alúmina. Primera Parte: Caracterización de catalizadores de Pt-Cu/y-alúmina por quimisorción de H2

    Directory of Open Access Journals (Sweden)

    Luis M. Carballo

    1999-09-01

    Full Text Available En este trabajo se analiza el efecto de la composición de catalizadores de Pt-Cu/y-alúmina sobre el área superficial reactiva correspondiente a la oxidación total de propileno. Los ensayos experimentales se efectuaron en un reactor diferencial que se usó tanto para la caracterización del catalizador "in situ" mediante la medición de la quimisorción selectiva de H2. Además, se discuten los efectos y las interacciones bimetálicas que ocurren con frecuencia en los catalizadores soportados. A partir de los estudios de adsorción química de H2 sobre los catalizadores soportados de Pt-Cu se encontró, mediante la aplicación de la teoría de la solución regular a la superficie de los cristales y teniendo en cuenta que el H2 se adsorbe químicamente solamente sobre los átomos superficiales de Pt (se observó que el hidrógeno no se quimisorbe sobre el Cu, que los átomos de Cu se segregan a la superficie de los cristalitos bimetálicos.

  10. Oxidación de propileno sobre catalizadores Pt-Cu/y-alúmina. Primera Parte: Caracterización de catalizadores de Pt-Cu/y-alúmina por quimisorción de H2

    Directory of Open Access Journals (Sweden)

    Luis M. Carballo

    2011-02-01

    Full Text Available En este trabajo se analiza el efecto de la composición de catalizadores de Pt-Cu/y-alúmina sobre el área superficial reactiva correspondiente a la oxidación total de propileno. Los ensayos experimentales se efectuaron en un reactor diferencial que se usó tanto para la caracterización del catalizador "in situ" mediante la medición de la quimisorción selectiva de H2. Además, se discuten los efectos y las interacciones bimetálicas que ocurren con frecuencia en los catalizadores soportados. A partir de los estudios de adsorción química de H2 sobre los catalizadores soportados de Pt-Cu se encontró, mediante la aplicación de la teoría de la solución regular a la superficie de los cristales y teniendo en cuenta que el H2 se adsorbe químicamente solamente sobre los átomos superficiales de Pt (se observó que el hidrógeno no se quimisorbe sobre el Cu, que los átomos de Cu se segregan a la superficie de los cristalitos bimetálicos.

  11. Implicaciones de la inmigración italiana en novelas realistas Dialógicas y Experimentales de mediados de s. XX argentino

    Directory of Open Access Journals (Sweden)

    Jorge Bracamonte

    2015-01-01

    Full Text Available ¿Qué valoraciones sociales se construyen en la novela dialógica y experimental argentina entre 1940-1965 sobre las genealogías del pasado inmigratorio de origen italiano? ¿En qué medida esta novelística enriquece esa percepción y a la vez se enriquece por la misma? Realizamos nuestra indagación desde Los robinsones (1946 de Roger Pla (1912-1982, Adán Buenosayres (1948 de Leopoldo Marechal (1900-1970, La casa (1954 de Manuel Mujica Lainez (1910-1984, Los premios (1960 y Rayuela (1963 de Julio Cortázar (1914-1984 y Sobre héroes y tumbas (1961 de Ernesto Sábato (1911-2011.

  12. Long-term physical outcome in patients with septic shock

    DEFF Research Database (Denmark)

    Poulsen, J. B.; Møller, Kirsten; Kehlet, H

    2009-01-01

    Limited information is available on physical function after septic shock. The aim of the present study was to assess the physical outcome in survivors 1 year after septic shock.......Limited information is available on physical function after septic shock. The aim of the present study was to assess the physical outcome in survivors 1 year after septic shock....

  13. On the maximum energy of shock-accelerated cosmic rays at ultra-relativistic shocks

    OpenAIRE

    Reville, B; Bell, A R

    2014-01-01

    The maximum energy to which cosmic rays can be accelerated at weakly-magnetised ultra-relativistic shocks is investigated. We demonstrate that for such shocks, in which the scattering of energetic particles is mediated exclusively by ion skin-depth scale structures, as might be expected for a Weibel-mediated shock, there is an intrinsic limit on the maximum energy to which particles can be accelerated. This maximum energy is determined from the requirement that particles must be isotropised i...

  14. Mortality rates in pediatric septic shock

    National Research Council Canada - National Science Library

    Rusmawatiningtyas, Desy; Nurnaningsih, Nurnaningsih

    2017-01-01

    .... Recent investigations from developed countries have reported mortality rates of 20-30%. Few studies have reported mortality rates from pediatric septic shock in intensive care settings in developing countries with limited resources.  Objective...

  15. Integrated microelectromechanical gyroscope under shock loads

    Science.gov (United States)

    Nesterenko, T. G.; Koleda, A. N.; Barbin, E. S.

    2018-01-01

    The paper presents a new design of a shock-proof two-axis microelectromechanical gyroscope. Without stoppers, the shock load enables the interaction between the silicon sensor elements. Stoppers were installed in the gyroscope to prevent the contact interaction between electrodes and spring elements with fixed part of the sensor. The contact of stoppers occurs along the plane, thereby preventing the system from serious contact stresses. The shock resistance of the gyroscope is improved by the increase in its eigenfrequency at which the contact interaction does not occur. It is shown that the shock load directed along one axis does not virtually cause the movement of sensing elements along the crosswise axes. Maximum stresses observed in the proposed gyroscope at any loading direction do not exceed the value allowable for silicon.

  16. Medical and biomedical applications of shock waves

    CERN Document Server

    Loske, Achim M

    2017-01-01

    This book provides current, comprehensive, and clear explanations of the physics behind medical and biomedical applications of shock waves. Extracorporeal shock wave lithotripsy is one of the greatest medical advances of our time, and its techniques and clinical devices are continuously evolving. Further research continues to improve the understanding of calculi fragmentation and tissue-damaging mechanisms. Shock waves are also used in orthopedics and traumatology. Possible applications in oncology, cardiology, dentistry, gene therapy, cell transfection, transformation of fungi and bacteria, as well as the inactivation of microorganisms are promising approaches for clinical treatment, industrial applications and research. Medical and Biomedical Applications of Shock Waves is useful as a guide for students, technicians and researchers working in universities and laboratories. Chemists, biologists, physicians and veterinarians, involved in research or clinical practice will find useful advice, but also engineer...

  17. Propagation of inflationary shocks in Costa Rica

    Directory of Open Access Journals (Sweden)

    Adolfo Rodríguez Vargas

    2013-06-01

    Full Text Available Abstract We present an estimation of propagation effects of inflationary shocks to groups and specific products of the CPI using a SVAR framework.  We found significant propagation effects for 6 out of the 12 groups of the CPI, which together account for 72% of the basket.  These groups include those related to food, home apparel and housekeeping services and transportation. The estimations suggest that shocks to Food and Non-Alcoholic Beverages and to fuels are passed through entirely to the rest of the CPI basket. The majority of the most important propagation effects occur between 6 and 10 months after the shocks.  This includes propagation effects stemming from shocks to fuels, products with regulated price, tradables and the IPPI index.

  18. Shock wave science and technology reference library

    CERN Document Server

    2009-01-01

    This book, as a volume of the Shock Wave Science and Technology Reference Library, is primarily concerned with detonation waves or compression shock waves in reactive heterogeneous media, including mixtures of solid, liquid and gas phases. The topics involve a variety of energy release and control processes in such media - a contemporary research field that has found wide applications in propulsion and power, hazard prevention as well as military engineering. The six extensive chapters contained in this volume are: - Spray Detonation (SB Murray and PA Thibault) - Detonation of Gas-Particle Flow (F Zhang) - Slurry Detonation (DL Frost and F Zhang) - Detonation of Metalized Composite Explosives (MF Gogulya and MA Brazhnikov) - Shock-Induced Solid-Solid Reactions and Detonations (YA Gordopolov, SS Batsanov, and VS Trofimov) - Shock Ignition of Particles (SM Frolov and AV Fedorov) Each chapter is self-contained and can be read independently of the others, though, they are thematically interrelated. They offer a t...

  19. Red blood cell transfusion in septic shock

    DEFF Research Database (Denmark)

    Rosland, Ragnhild G; Hagen, Marte U; Haase, Nicolai

    2014-01-01

    BACKGROUND: Treating anaemia with red blood cell (RBC) transfusion is frequent, but controversial, in patients with septic shock. Therefore we assessed characteristics and outcome associated with RBC transfusion in this group of high risk patients. METHODS: We did a prospective cohort study at 7...... general intensive care units (ICUs) including all adult patients with septic shock in a 5-month period. RESULTS: Ninety-five of the 213 included patients (45%) received median 3 (interquartile range 2-5) RBC units during shock. The median pre-transfusion haemoglobin level was 8.1 (7.4-8.9) g...... and SAPS II and SOFA-score on day 1. CONCLUSIONS: The decision to transfuse patients with septic shock was likely affected by disease severity and bleeding, but haemoglobin level was the only measure that consistently differed between transfused and non-transfused patients....

  20. Shock waves: The Maxwell-Cattaneo case.

    Science.gov (United States)

    Uribe, F J

    2016-03-01

    Several continuum theories for shock waves give rise to a set of differential equations in which the analysis of the underlying vector field can be done using the tools of the theory of dynamical systems. We illustrate the importance of the divergences associated with the vector field by considering the ideas by Maxwell and Cattaneo and apply them to study shock waves in dilute gases. By comparing the predictions of the Maxwell-Cattaneo equations with shock wave experiments we are lead to the following conclusions: (a) For low compressions (low Mach numbers: M) the results from the Maxwell-Cattaneo equations provide profiles that are in fair agreement with the experiments, (b) as the Mach number is increased we find a range of Mach numbers (1.27 ≈ M(1) M_{2}) shock wave solutions can be found though they differ significantly from experiments.

  1. Experimental Investigation of Shock Wave Surfing

    CERN Document Server

    Parziale, N J; Hornung, H G; Shepherd, J E

    2010-01-01

    Shock wave surfing is investigated experimentally in GALCIT's Mach 4.0 Ludwieg Tube. Shock wave surfing occurs when a secondary free-body follows the bow shock formed by a primary free-body; an example of shock wave surfing occurs during meteorite breakup. The free-bodies in the current investigation are nylon spheres. During each run in the Ludwieg tube a high speed camera is used to capture a series of schlieren images; edge tracking software is used to measure the position of each sphere. Velocity and acceleration are had from processing the position data. The radius ratio and initial orientation of the two spheres are varied in the test matrix. The variation of sphere radius ratio and initial angle between the centers of gravity are shown to have a significant effect on the dynamics of the system.

  2. Nonequilibrium recombination after a curved shock wave

    Science.gov (United States)

    Wen, Chihyung; Hornung, Hans

    2010-02-01

    The effect of nonequilibrium recombination after a curved two-dimensional shock wave in a hypervelocity dissociating flow of an inviscid Lighthill-Freeman gas is considered. An analytical solution is obtained with the effective shock values derived by Hornung (1976) [5] and the assumption that the flow is ‘quasi-frozen’ after a thin dissociating layer near the shock. The solution gives the expression of dissociation fraction as a function of temperature on a streamline. A rule of thumb can then be provided to check the validity of binary scaling for experimental conditions and a tool to determine the limiting streamline that delineates the validity zone of binary scaling. The effects on the nonequilibrium chemical reaction of the large difference in free stream temperature between free-piston shock tunnel and equivalent flight conditions are discussed. Numerical examples are presented and the results are compared with solutions obtained with two-dimensional Euler equations using the code of Candler (1988) [10].

  3. Density shock waves in confined microswimmers

    CERN Document Server

    Tsang, Alan Cheng Hou

    2015-01-01

    Motile and driven particles confined in microfluidic channels exhibit interesting emergent behavior from propagating density bands to density shock waves. A deeper understanding of the physical mechanisms responsible for these emergent structures is relevant to a number of physical and biomedical applications. Here, we study the formation of density shock waves in the context of an idealized model of microswimmers confined in a narrow channel and subject to a uniform external flow. Interestingly, these density shock waves exhibit a transition from `subsonic' with compression at the back to `supersonic' with compression at the front of the population as the intensity of the external flow increases. This behavior is the result of a non-trivial interplay between hydrodynamic interactions and geometric confinement, and is confirmed by a novel quasilinear wave model that properly captures the dependence of the shock formation on the external flow. These findings can be used to guide the development of novel mechan...

  4. SPECIAL PURPOSE SHOCK TUBE for BLAST ASSESSMENT

    Data.gov (United States)

    Federal Laboratory Consortium — This device is a specially designed shock tube for testing fabric samples in a controlled environment. The device determines the appropriate types of sensors to be...

  5. Hypovolemic shock after air reduction of intussusception

    Energy Technology Data Exchange (ETDEWEB)

    Royal, S.A. [University of Alabama Hospitals, Dept. of Radiology, Birmingham, AL (United States); Childrens' Hospital of Alabama, Dept. of Radiology, Birmingham, AL (United States)

    2001-03-01

    A 7-month-old white baby girl developed hypovolemic shock requiring resuscitation secondary to an air enema reduction of intussusception. The implications of this case for standardization of the management techniques in this setting are emphasized. (orig.)

  6. Shock Thermodynamic Applied Research Facility (STAR)

    Data.gov (United States)

    Federal Laboratory Consortium — The STAR facility, within Sandia's Solid Dynamic Physics Department, is one of a few institutions in the world with a major shock-physics program. This is the only...

  7. Smoother Turbine Blades Resist Thermal Shock Better

    Science.gov (United States)

    Czerniak, Paul; Longenecker, Kent; Paulus, Don; Ullman, Zane

    1991-01-01

    Surface treatment increases resistance of turbine blades to low-cycle fatigue. Smoothing removes small flaws where cracks start. Intended for blades in turbines subject to thermal shock of rapid starting. No recrystallization occurs at rocket-turbine operating temperatures.

  8. Estrategias experimentales para el estudio de las propiedades de la proteína Core del virus de la hepatitis C

    Directory of Open Access Journals (Sweden)

    Gonzálo Correa Arango

    2004-03-01

    Full Text Available

    El modelo de infección por el Virus de la Hepatitis C (VHC se ha convertido en el tópico de interés de numerosos equipos de investigación, considerando el alto porcentaje de infección persistente asociada al VHC. En efecto, del 50 al 80% de los pacientes con infección por el VHC, desarrollan infección persistente, que puede evolucionar a cirrosis y carcinoma hepatocelular (HCC. Este modelo presenta dos obstáculos mayores para su estudio: la ausencia de un sistema eficiente de replicación viral in vitro y el limitado número de modelos animales.

    La proteína Core del VHC, además de ser la unidad estructural de la cápside viral, parece estar implicada en las estrategias virales de persistencia y oncogénesis; nuestro grupo ha planteado estrategias experimentales para estudiar algunas de sus propiedades, tales como su capacidad inmunonoduladora en cultivos de cálulas dendríticas humanas, su capacidad de modificar la expresión del ARNm en células HepG2 con expresión transitoria de Core y la presencia de esta proteína en tejido hepático proveniente de pacientes con diagnóstico de HCC; dichas estrategias experimentales han sido:

    Producción de la proteína Core del VHC en el sistema baculovirus y purificación en condiciones nativas para su evaluación en ensayos biológicos.

    Expresión transitoria de la proteína Core del VHC en la línea celular HepG2, mediante transducción con partículas recombinantes del Virus Semliki Forest (SFV.

    Estudio de la expresión de p53

  9. Accuracy of Rapid Ultrasound in Shock (RUSH) Exam for Diagnosis of Shock in Critically Ill Patients.

    Science.gov (United States)

    Ghane, Mohammad Reza; Gharib, Mohammad Hadi; Ebrahimi, Ali; Samimi, Kaveh; Rezaee, Maryam; Rasouli, Hamid Reza; Kazemi, Hossein Mohammad

    2015-02-01

    Rapid ultrasound in shock (RUSH) is the most recent emergency ultrasound protocol, designed to help clinicians better recognize distinctive shock etiologies in a shorter time frame. In this study, we evaluated the accuracy of the RUSH protocol, performed by an emergency physician or radiologist, in predicting the type of shock in critical patients. An emergency physician or radiologist performed the RUSH protocol for all patients with shock status at the emergency department. All patients were closely followed to determine their final clinical diagnosis. The agreement between the initial impression provided by RUSH and the final diagnosis was investigated by calculating the Kappa index. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of RUSH for diagnosis of each case. We performed RUSH on 77 patients. Kappa index was 0.71 (P Value = 0.000), reflecting acceptable general agreement between initial impression and final diagnosis. For hypovolemic, cardiogenic and obstructive shock, the protocol had an NPV above 97% yet it had a lower PPV. For shock with distributive or mixed etiology, RUSH showed a PPV of 100% but it had low sensitivity. Subgroup analysis showed a similar Kappa index for the emergency physician and radiologist (0.70 and 0.73, respectively) in performing rush. This study highlights the role of the RUSH exam performed by an emergency physician, to make a rapid and reliable diagnosis of shock etiology, especially in order to rule out obstructive, cardiogenic and hypovolemic shock types in initial exam of shock patients.

  10. Implications of heterogeneity in the shock wave propagation of dynamically shocked materials

    Science.gov (United States)

    LaJeunesse, Jeff

    The field of shock physics as a whole has only recently begun to pay particular attention to modeling heterogeneous materials under shock loading. These materials are important because of their practicality in terms of creating stronger, more shock resistant materials. To understand why they absorb shock impact energy better than homogeneous materials means that the small-scale processes that occur during the shock loading of these heterogeneous materials needs to be understood. Recent computational experiments, called mesoscale simulations, have shown that explicitly incorporating small-scale heterogeneous features into hydrocode simulations allows the bulk shock response of the heterogeneous material to be observed while not requiring the use of empirically determined constitutive equations. Including these features in simulations can offer insights into the irreversible mechanisms that dominate the propagation of shock waves in heterogeneous materials. Three cases where the mesoscale approach for modeling the dynamic shock loading of heterogeneous materials are presented. These materials fall into three categories: granular - dry sand, granular with binder - concrete, and granular contained in a metal foam with a binder - granular explosive contained in an aluminum foam. The processes in which shock waves propagate through each material are addressed and relationships between the three materials are discussed. Particle velocity profiles for dry sand and concrete was obtained from Harvard University and Eglin Air Force Base, respectively. Mesoscale simulations using CTH are conducted for each type of heterogeneous material and the results are compared to the experimental data.

  11. THE EFFECTS OF AREA CONTRACTION ON SHOCK WAVE STRENGTH AND PEAK PRESSURE IN SHOCK TUBE

    Directory of Open Access Journals (Sweden)

    A. M. Mohsen

    2012-06-01

    Full Text Available This paper presents an experimental investigation into the effects of area contraction on shock wave strength and peak pressure in a shock tube. The shock tube is an important component of the short duration, high speed fluid flow test facility, available at the Universiti Tenaga Nasional (UNITEN, Malaysia. The area contraction was facilitated by positioning a bush adjacent to the primary diaphragm section, which separates the driver and driven sections. Experimental measurements were performed with and without the presence of the bush, at various diaphragm pressure ratios, which is the ratio of air pressure between the driver (high pressure and driven (low pressure sections. The instantaneous static pressure variations were measured at two locations close to the driven tube end wall, using high sensitivity pressure sensors, which allow the shock wave strength, shock wave speed and peak pressure to be analysed. The results reveal that the area contraction significantly reduces the shock wave strength, shock wave speed and peak pressure. At a diaphragm pressure ratio of 10, the shock wave strength decreases by 18%, the peak pressure decreases by 30% and the shock wave speed decreases by 8%.

  12. Design and Fabrication of hand operated mini Shock Tube

    Science.gov (United States)

    Nambiar, Gautham K.; Sriram, M.; Dharanidhar, M.; Nair, Prashant G.; Nagaraja, S. R.

    2017-08-01

    Shock waves have been used for medical, biological and industrial applications. In this paper design, frication and calibration of a low cost mini shock tube is presented. Commercial FEM software COMSOL multiphysics is used for analysis of shock tube flows. The hand operated mini shock tube is capable of generating shock Mach numbers up to 1.8, peak over pressures up to 8 bar. Experimental and theoretical values of pressure ratio jump primary and reflected shock closely agree with each other. The fabricated shock tube is used for free forming of metallic foils.

  13. Computational and experimental investigation of dynamic shock reflection phenomena

    CSIR Research Space (South Africa)

    Naidoo, K

    2007-07-01

    Full Text Available the basic anatomy of the oblique shock system previously attached to the wedge leading edge (Fig. 4). There still remains an incident oblique shock wave, a small Mach stem and a reflected oblique shock wave at θ = -0.5◦. As the “orphan”shock system washes... Incident shock wave Mach stem Reflected shock wave Fig. 4. Anatomy of the “orphan shock”system at θ = -0.5◦ : case 12 shock begins to diminish in strength (Fig. 5). At the same time the triple point continues to move toward the wall. At the time θ = -1...

  14. Estudios sobre la reactividad de harinas crudas de cemento tratadas con rápidos y diferentes calentamientos

    Directory of Open Access Journals (Sweden)

    Weisweiler, W.

    1988-09-01

    Full Text Available Not available.

    Estudios experimentales llevados a cabo a una temperatura dada de calcinación, sirvieron para observar el efecto de las altas velocidades de calentamiento sobre las reacciones del clinker. Mientras que un aumento de la reactividad de los materiales fue claramente detectada cuando la velocidad pasó de 20 K/min a tomar valores iguales y mayores a 100 K/min, un negativo efecto sobre el Tiempo de Reacción Completa o "Período de Calcinación a Punto" no pudo ser establecido. Considerando además que el tiempo necesario para llevar a la materia prima hasta la temperatura de reacción, es necesariamente un tiempo inefectivo, podrían las plantas productoras de cemento obtener mayores rendimientos en tiempo y espacio, utilizando altas cuotas de calentamiento. Estudios de microscopía probaron que con el aumento de las velocidades de calentamiento, hubo una mayor generación de microcristales incidiendo directamente sobre la molienda y calidad del clinker. [de] Untersuchungen zur Reaktivität van zementrohmehlen nach verschieden schneller Aufheizung. Modellversuche mit linearen Aufheizgeschwindigkeiten solten zeigen, ob bei einer vorgegebenen Brenntemperatur die Verklinkerungsreaktionen beeinfluβt werden können. Während eindeutige Steigerungen der Kalkbindungsraten lediglich zwischen 20 K/min und Aufheizgeschwindigkeiten >=100 K/min nachweisbar waren, konnten negative Auswirkungen auf die Garbranddauern bei keiner Versuchsserie festgestellt werden. Unter Berücksichtigung der zur Aufheizung der Rohstoffe notwendigen Totzeiten, können bei den technischen Zementproduktionsanlagen nach schneller Aufheizung höhere Raum-Zeit-Ausbeuten erreicht werden. Mikroskopische Untersuchungen ergaben, daβ durch Erhöhung der Aufheizraten der Anteil mikrokristalliner Klinkerphasen zunimmt, was sich direkt aut die Zementklinkermahibarkeit und die Klinkerqualität aswirkt.

  15. Efecto del ozono sobre la población microbiana del suelo y el crecimiento de plantas de fresa

    Directory of Open Access Journals (Sweden)

    Carlos Manuel Bucio Villalobos

    2016-04-01

    Full Text Available Una de las formas de control de microorganismos fitopatógenos del suelo es el uso de fumigantes, los cuales, se ha demostrado, tienen efecto contaminante del ambiente. Con la finalidad de ofrecer una alternativa amigable con el entorno se propuso la presente investigación con el objetivo de evaluar la eficacia del ozono disuelto en el agua aplicada como riego, para reducir las poblaciones de microorganismos habitantes del suelo en una plantación de fresa, además de evaluar su posible efecto positivo indirecto sobre el crecimiento de las plantas. Con la ayuda de un generador se aplicó ozono disuelto en el agua a través del sistema de riego por goteo establecido en una parcela plantada con fresa de la variedad Camino Real. Se tomaron muestras de suelo en 10 sitios aleatorios de las parcelas experimentales un día antes de la aplicación y un día después, a estas se les cuantificó poblaciones de hongos, bacterias y nematodos. Los resultados de la aplicación del ozono disuelto en el agua de riego mostró una reducción de las poblaciones totales de hongos, bacterias y nematodos habitantes del suelo de 22.8 × 104 a 8.5 × 104, de 4.3 × 106 a 1.2 × 106 unidades formadoras de colonias (UFC por gramo de suelo y de 20.3 a 10.4 nematodos filiformes por 100 mL de suelo, respectivamente, lo que demostró una eficacia del ozono como fumigante sobre los tres tipos de microorganismos evaluados, similar a la del metam sodio (testigo. La aplicación única de ozono al inicio de la plantación no tuvo efecto sobre el crecimiento de las plantas de fresa.

  16. Component Representation for Shock Qualified Foundation Structure

    OpenAIRE

    Timothy Coats; Michael Cooper; Kevin Arden; Fred Russell

    2003-01-01

    Navy ship foundations are typically designed for shock using the Navy's Dynamic Design Analysis Method. The NAVSEA 0908-LP-000-3010, Rev. 1 manual states that a component modeled as a lumped mass with rigid links should not provide constraint to the support structure. This ensures foundations are designed to withstand all shock loads without accounting for additional stiffness provided by the component. Investigations are provided herein to illustrate the trade-offs and consequences of severa...

  17. Clinical management guidelines of pediatric septic shock

    OpenAIRE

    Khilnani Praveen

    2005-01-01

    Septic shock in children is the prototype combination of hypovolemia,cardiogenic and distributive shock. Recently published American college of critical care medinie(ACCM )recommendations for hemodynamic support of neonatal and pediatric patients with sepsis,Surviving sepsis campaign and its pediatric considerations and subsequent revision of definitions for pediatric sepsis has led to compilation of this review article. Practical application of this information in Indian set up in a child wi...

  18. Fast Electrocardiogram Amplifier Recovery after Defibrillation Shock

    Directory of Open Access Journals (Sweden)

    Ivan Dotsinsky

    2005-04-01

    Full Text Available A procedure for fast ECG amplifier recovery after defibrillation shocks was developed and simulated in the MATLAB environment. Exponentially decaying post-shock voltages have been recorded. Signals from the AHA database are taken and mixed with the recorded exponential disturbances. The algorithm applies moving averaging (comb filter on the compound input signal, thereby obtaining the samples of the disturbance. They are currently subtracted from the input signal. The results obtained show that its recovery is practically instantaneous.

  19. Electrostatic Energy Exchange in Shock Acceleration

    Science.gov (United States)

    Barchas, Joseph A.

    Plasma shocks are very common occurrences, and diffusive shock acceleration is a simple and efficient mechanism for generating cosmic rays. A shock's main effect is turbulent dissipation, which rapidly thermalizes the downstream plasma. Diffusive shock acceleration produces a non-thermal component to the particle distributions (quasi-power-law tails) which translates to non-thermal photon spectra, as seen in supernova remnants, jets in active galactic nuclei, and gamma-ray bursts. In supernova remnants, X-ray observations show that inferred proton temperatures are considerably cooler than standard shock heating predicts. A cross-shock electrostatic potential, akin to a double layer, is reasoned to exist in certain conditions due to the different inertial gyration scales of the plasma species. It provides a mechanism for energy exchange between species, and should result in a respective heating/cooling of the electrons/ions. It modifies the electron/ion distributions, which couple through radiative processes to the observed X-ray emission. In this thesis, the effects of cross-shock electrostatics are explored using a Monte Carlo simulation, where test particles gyrate and stochastically diffuse in a background fluid pre-defined by MHD jump conditions.A cross-shock electric field is derived from the steady-state spatial distribution of particles via a modified Poisson's equation that includes Debye screening, and the simulation is rerun with this field superimposed on the background magnetic and drift electric fields. This feedback loop continues until a self-consistent solution is obtained. Results show a significant departure of the particle distributions from the usual thermal+power-law form, and clearly demonstrates substantial energy exchange between the electron and ion populations.

  20. Device for absorbing mechanical shock

    Science.gov (United States)

    Newlon, C.E.

    1979-08-29

    This invention is a comparatively inexpensive but efficient shock-absorbing device having special application to the protection of shipping and storage cylinders. In a typical application, two of the devices are strapped to a cylinder to serve as saddle-type supports for the cylinder during storage and to protect the cylinder in the event it is dropped during lifting or lowering operations. In its preferred form, the invention includes a hardwood plank whose grain runs in the longitudinal direction. The basal portion of the plank is of solid cross-section, whereas the upper face of the plank is cut away to form a concave surface fittable against the sidewall of a storage cylinder. The concave surface is divided into a series of segments by transversely extending, throughgoing relief slots. A layer of elastomeric material is positioned on the concave face, the elastomer being extrudable into slots when pressed against the segments by a preselected pressure characteristic of a high-energy impact. The compressive, tensile, and shear properties of the hardwood and the elastomer are utilized in combination to provide a surprisingly high energy-absorption capability.

  1. Shock hemorrágico

    Directory of Open Access Journals (Sweden)

    Dr. M. Víctor Parra

    2011-05-01

    Full Text Available El shock hemorrágico es la principal causa de muerte en el trauma, la principal causa de muertes potencialmente prevenible y una de las principales causas de muerte en la población menor de 44 años. La hemorragia masiva puede producir inestabilidad hemodinámica, disminución de la perfusión tisular, daño de órganos y muerte. Los principales objetivos de la resucitación son restaurar el volumen sanguíneo circulante y detener la hemorragia, mientras se activan los protocolos de manejo de la hemorragia masiva. Si bien el método óptimo de resucitación no ha sido claramente establecido, el uso de fluidos intravenosos y productos sanguíneos son elementos esenciales del manejo. Los defectos hemostáticos son frecuentes en la hemorragia masiva y evolucionan rápidamente. Se recomienda el uso precoz de plasma fresco congelado y plaquetas para prevenir el mecanismo dilucional de la coagulopatía, y el manejo agresivo de ésta una vez establecida. Finalmente, el manejo posterior a la emergencia incluye los cuidados intensivos para una monitorización estricta y el manejo de las eventuales complicaciones sistémicas, como la falla multiorgánica.

  2. heavy ion acceleration at shocks

    Science.gov (United States)

    Shevchenko, V. I.; Galinsky, V.

    2009-12-01

    The theoretical study of alpha particle acceleration at a quasi-parallel shock due to interaction with Alfven waves self-consistently excited in both upstream and downstream regions was conducted using a scale-separation model [1]. The model uses conservation laws and resonance conditions to find where waves will be generated or dumped and hence particles will be pitch--angle scattered as well as the change of the wave energy due to instability or damping. It includes in consideration the total distribution function (the bulk plasma and high energy tail), so no any assumptions (e.g. seed populations, or some ad-hoc escape rate of accelerated particles) are required. In previous studies heavy ions were treated as perfect test particles, they only experienced the Alfven turbulence excited by protons and didn’t contribute to turbulence generation. In contrast to this approach, we consider the ion scattering on hydromagnetic turbulence generated by both protons and ions themselves. It is important for alpha particles with their relatively large mass-loading parameter that defines efficiency of the wave excitation by alpha particles. The energy spectra of alpha particles is found and compared with those obtained in test particle approximation. [1] Galinsky, V.L., and V.I. Shevchenko, Astrophys. J., 669, L109, 2007.

  3. Contagion Shocks in One Dimension

    Science.gov (United States)

    Bertozzi, Andrea L.; Rosado, Jesus; Short, Martin B.; Wang, Li

    2015-02-01

    We consider an agent-based model of emotional contagion coupled with motion in one dimension that has recently been studied in the computer science community. The model involves movement with a speed proportional to a "fear" variable that undergoes a temporal consensus averaging based on distance to other agents. We study the effect of Riemann initial data for this problem, leading to shock dynamics that are studied both within the agent-based model as well as in a continuum limit. We examine the behavior of the model under distinguished limits as the characteristic contagion interaction distance and the interaction timescale both approach zero. The limiting behavior is related to a classical model for pressureless gas dynamics with "sticky" particles. In comparison, we observe a threshold for the interaction distance vs. interaction timescale that produce qualitatively different behavior for the system - in one case particle paths do not cross and there is a natural Eulerian limit involving nonlocal interactions and in the other case particle paths can cross and one may consider only a kinetic model in the continuum limit.

  4. Septic Shock: Advances in Diagnosis and Treatment.

    Science.gov (United States)

    Seymour, Christopher W; Rosengart, Matthew R

    2015-08-18

    Septic shock is a clinical emergency that occurs in more than 230,000 US patients each year. OBSERVATIONS AND ADVANCES: In the setting of suspected or documented infection, septic shock is typically defined in a clinical setting by low systolic (≤90 mm Hg) or mean arterial blood pressure (≤65 mm Hg) accompanied by signs of hypoperfusion (eg, oliguria, hyperlactemia, poor peripheral perfusion, or altered mental status). Focused ultrasonography is recommended for the prompt recognition of complicating physiology (eg, hypovolemia or cardiogenic shock), while invasive hemodynamic monitoring is recommended only for select patients. In septic shock, 3 randomized clinical trials demonstrate that protocolized care offers little advantage compared with management without a protocol. Hydroxyethyl starch is no longer recommended, and debate continues about the role of various crystalloid solutions and albumin. The prompt diagnosis of septic shock begins with obtainment of medical history and performance of a physical examination for signs and symptoms of infection and may require focused ultrasonography to recognize more complex physiologic manifestations of shock. Clinicians should understand the importance of prompt administration of intravenous fluids and vasoactive medications aimed at restoring adequate circulation, and the limitations of protocol-based therapy, as guided by recent evidence.

  5. The Shock State of Itokawa Sample

    Science.gov (United States)

    Zolensky, Michael; Nakamura, Tomoki; Mikouchi, Takashi; Hagiya, Kenji; Ohsumi, Kazumasa; Tanaka, Masahiko; Kimura, Makoto; Tsuchiyama, Akira; Nakato, Aiko; Ogami, Toshihiro; hide

    2012-01-01

    One of the fundamental aspects of any astromaterial is its shock history, since this factor elucidates critical historical events, and also because shock metamorphism can alter primary mineralogical and petrographic features, and reset chronologies [1]. Failure to take shock history into proper account during characterization can result in seriously incorrect conclusions being drawn. Thus the Hayabusa Preliminary Examination Team (HASPET) made shock stage determination of the Itokawa samples a primary goal [2]. However, we faced several difficulties in this particular research. The shock state of ordinary chondrite materials is generally determined by simple optical petrographic observation of standard thin sections. The Itokawa samples available to the analysis team were mounted into plastic blocks, were polished on only one side, and were of non-standard and greatly varying thickness, all of which significantly complicated petrographic analysis but did not prevent it. We made an additional estimation of the sample shock state by a new technique for this analysis - electron back-scattered diffraction (EBSD) in addition to standard petrographic techniques. We are also investigating the crystallinity of Itokawa olivine by Synchrotron X-ray diffraction (SXRD).

  6. Apuntes sobre encuestas electorales

    Directory of Open Access Journals (Sweden)

    Luis Benavente Gianella

    2013-12-01

    Full Text Available Las encuestas preelectorales suelen despertar gran interés por el valor predictivo que se les puede atribuir o que puedan tener, y por el efecto que puedan generar en los votantes. También se usan como herramienta efectiva para el manejo de las campañas de los candidatos. Existen tres tipos de encuestas electorales: preelectorales, boca de urna y postelectorales, en cada caso cumplen funciones diferentes en relación con los procesos electorales. Philippe Maarek (1 considera que la publicación de encuestas preelectorales influye en la decisión de voto mediante efectos directos e indirectos. Es en coyunturas preelectorales cuando las encuestas suelen concitar la mayor atención, especialmente por el valor predictivo que se les puede atribuir o que puedan tener, y por el efecto que puedan generar en los votantes, de manera especial en los indecisos, que constituyen un porcentaje usualmente muy alto durante casi toda la etapa preelectoral. Esto hace que las encuestas sean controvertidas y discutidas en el mundo. En los procesos electorales, las encuestas también son utilizadas como una herramienta efectiva para el manejo eficiente de las campañas de los candidatos, asumiendo de esta manera un papel protagónico y permanente en las campañas. Además de sus implicancias electorales, las encuestas tienen asimismo presencia en la vida política institucional en épocas no electorales. Actualmente son utilizadas para conocer la opinión de los ciudadanos acerca de diversos temas políticos, económicos y sociales. Las encuestadoras realizan sondeos periódicos sobre todos estos aspectos que son difundidos a través de los medios de comunicación, alimentando de este modo el debate político. En la actualidad, las encuestas de opinión son una práctica habitual en todos los países con regímenes democráticos, constituyéndose en un instrumento de medición de la opinión de los ciudadanos.

  7. Informe preliminar sobre paludrina

    Directory of Open Access Journals (Sweden)

    Aquiles Peñuela Rozo

    1948-05-01

    Full Text Available En el año de 1945, Curd Davey y Rose eligieron la pirimidina como substancia de experimentación debido a que esta substancia se encuentra en las nucleo-proteinas y por su presencia en algunas sulfadrogas especial mente la sulfadiazina, de conocidas propiedades anti-palúdicas. Ensayaron la pirimidina y derivados en infestaciones por plasmodium gallinaceum en gallinas; y comprobaron que estas substancias tenían realmente acción antipalúdica. Pero al trasladar sus experiencias al hombre, encontraron que la pirimidina y sus derivados eran demasiado tóxicos. Pensando, entonces, en la similitud química del grupo de la pirimida y de la guanidina, incluyeron este último grupo en los compuestos para ensayar, descubriendo que la inclusión de la guanidina aumentaba grandemente la acción de las substancias en experiencia. Se obtuvo de esta manera un producto denominado en el numero 4-888, o paludrina, cuya fórmula o nombre químico es N. P. clorofenil N5 isopropildiguanidina, droga que se encontró muy activa contra las formas sanguíneas del Plasmodium Gallinaceum y que también se hallo activa contra las formas exoeritrocíticas del parásito. Esta capacidad de obrar sobre la fase exoeritrocítica es prácticamente exclusiva de esta substancia. Hasta hace poco tiempo esta fase exoeritrocítica, había sido demostrada solamente en trabajos de experimentación en las  aves; pero en la actualidad ha quedado también demostrada en la enfermedad humana, por experiencias del Filipino Nolasco and África, quien logro demostrar el plasmodium Vivax en el tejido retículo endotelial del pulmón de enfermos de paludismo, aunque ya Brug, en el año de 1940 había hecho comunicaciones en el mismo sentido. Se comprende la grande importancia de la paludrina, en el tratamiento del paludismo; si se considera que las recidivas de la enfermedad son debidas a la existencia de esta fase xeoeritrocítica.

  8. Variation of cosmic ray injection across supernova shocks

    OpenAIRE

    Voelk, H. J.; Berezhko, E. G.; Ksenofontov, L. T.

    2003-01-01

    The injection rate of suprathermal protons into the diffusive shock acceleration process should vary strongly over the surface of supernova remnant shocks. These variations and the absolute value of the injection rate are investigated. In the simplest case, like for SN 1006, the shock can be approximated as being spherical in a uniform large-scale magnetic field. The injection rate depends strongly on the shock obliquity and diminishes as the angle between the ambient field and the shock norm...

  9. TRADICIÓN INVESTIGATIVA Y CONSTRUCTOS PARA COMPRENDER ASPECTOS DE LA INSERCIÓN PROFESIONAL DOCENTE: PLURALISMO CULTURAL, ACULTURACIÓN, SHOCK CULTURAL

    Directory of Open Access Journals (Sweden)

    Maurizia D' Antoni

    2010-01-01

    Full Text Available El fenómeno de la interculturalidad le impone a la academia cambios y reflexiones nuevas. En el presente ensayo reflexiono sobre los conceptos base que puedan guiar una investigación sobre inserción profesional de docentes extranjeros y extranjeras en la Universidad de Costa Rica (UCR. Sobresale el concepto de aculturación. Luego, tomo en cuenta el concepto de shock cultural y cómo Michael Winkelman resume la tradición de estudios sobre el tema, contrastándola con aportes de diversos estudiosos. Finalmente presento la visión de Paulo Freire, y de otros autores que comparten su visión del mundo, sobre qué es cultura y me sirvo de su aporte para analizar críticamente el concepto de shock cultural. Concluyo que, a pesar de la utilidad que puedan tener conceptos como shock cultural o inteligencia cultural, interesa más una visión de la cultura que tenga como punto de referencia el contexto

  10. Efecto antihipertensivo del extracto de Piper aduncum ‘matico’ sobre la hipertensión inducida por L-NAME en ratones

    Directory of Open Access Journals (Sweden)

    Jorge Arroyo

    2012-10-01

    Full Text Available Introducción: El Piper aduncum es una planta conocida como matico. Se le atribuye efectos antihipertensivo, antiinflamatorio, cicatrizante. Objetivos: Determinar el efecto antihipertensivo del extracto de Piper aduncum ‘matico’, sobre la hipertensión inducida por L-NAME, en ratones. Diseño: Experimental. Lugar: Facultades de Medicina y de Farmacia y Bioquímica, Universidad Nacional Mayor de San Marcos, Lima, Perú. Material biológico: Extracto etanólico de las hojas de Piper aduncum y ratas. Intervenciones: Se utilizó seis grupos de seis ratones Muss musculus cada uno, uno sin hipertensión (control negativo y cuatro con hipertensión inducida por L-NAME: un control positivo y tres grupos para las dosis de 50, 150 y 300 mg/kg, respectivamente. El tratamiento se realizó por vía oral, una vez por día, durante 25 días. Las mediciones de la presión arterial sistólica (PAS, presión arterial diastólica (PAD y presión arterial media (PAM fueron realizadas dos veces por semana (martes y viernes y se consideró las mediciones entre los días 19 y 23 de iniciado el tratamiento. Principales medidas de resultados: Actividad antihipertensiva. Resultados: En los días 19 y 23 se observó los mejores niveles de presión arterial en el grupo control y los experimentales, correspondiendo a las mediciones 6 y 7. La eficacia antihipertensiva para enalapril fue 24,1 a 20,6%, respectivamente, seguida por matico, entre 24,9 y 13,7% (p<0,05. Conclusiones: En las condiciones experimentales, se demostró la actividad antihipertensiva del extracto etanólico de hojas de Piper aduncum ‘matico’.

  11. FORMACIÓN INICIAL DEL PROFESORADO SOBRE GÉNERO Y COEDUCACIÓN: IMPACTOS METACOGNITIVOS DE LA INCLUSIÓN CURRICULAR TRANSVERSAL SOBRE SEXISMO Y HOMOFOBIA

    Directory of Open Access Journals (Sweden)

    Rafael García Pérez

    2013-01-01

    Full Text Available Investigamos una innovación educativa para incorporar transversalmente la perspectiva de género en la formación inicial de profesionales de la educación. Se experimenta en las asignaturas de Diagnóstico en Educación (1º Psicopedagogía y Técnicas e Instrumentos de Diagnóstico (2º Pedagogía, con muy similares planteamientos, profesorado y materiales didácticos compartidos. La incorporación transversal de la perspectiva de género se facilita por la necesidad de contar con ejemplos y casos para el estudio de los contenidos metodológicos, vinculándolos a los trabajos prácticos de las asignaturas. Se aplica la lógica comparativo-causal en un estudio pre-experimental, ex post facto, aplicando pos-test con grupos naturales (experimentales y de control. La muestra incidental implica a 348 participantes, alumnos y alumnas de la Universidad de Sevilla. Se aplican test metacognitivos tipo CERT (conocimiento y seguridad que permiten valorar el ajuste metacognitivo a través de variables como la propia seguridad, la coherencia y el realismo en el manejo de los conceptos. Los resultados demuestran el impacto metacognitivo causado en el pensamiento sobre género y coeducación que maneja el alumnado universitario participante en estas iniciativas, concluyendo con un llamamiento a la mejora de los títulos que aportan formación inicial para los futuros profesores y profesoras del sistema educativo.

  12. Back-transformation of high-pressure minerals in shocked chondrites: Low-pressure mineral evidence for strong shock

    OpenAIRE

    Hu, Jinping; Sharp, Thomas G.

    2017-01-01

    Post-shock annealing of meteorites can destroy their shock-induced features, particularly high-pressure minerals, and complicate the estimation of impact pressure–temperature conditions. However, distinguishing post-shock annealing features from thermal metamorphism effects can be practically difficult. Here we report results from Mbale, a highly shocked L chondrite, to investigate the mechanisms, kinetics and identification criteria for post-shock annealing of high-pressure signatures. Olivi...

  13. Arboles binomiales para la valoracion de opciones sobre procesos derivados de la ecuacion diferencial estocastica autonoma

    National Research Council Canada - National Science Library

    Marin-Sanchez, Freddy

    2010-01-01

    .... Se muestran algunos resultados numericos experimentales de valoracion de opciones Europeas para el proceso log-normal y para los procesos de reversion a la media con ruido aditivo y ruido proporcional para diferentes fechas de expiracion.

  14. Back-transformation of high-pressure minerals in shocked chondrites: Low-pressure mineral evidence for strong shock

    Science.gov (United States)

    Hu, Jinping; Sharp, Thomas G.

    2017-10-01

    Post-shock annealing of meteorites can destroy their shock-induced features, particularly high-pressure minerals, and complicate the estimation of impact pressure-temperature conditions. However, distinguishing post-shock annealing features from thermal metamorphism effects can be practically difficult. Here we report results from Mbale, a highly shocked L chondrite, to investigate the mechanisms, kinetics and identification criteria for post-shock annealing of high-pressure signatures. Olivine fragments within shock-melt veins in Mbale occur as chemically heterogeneous nanocrystalline aggregates that contain trace wadsleyite and ringwoodite. Their strong variation in fayalite content provides evidence of iron partitioning during transformation of olivine to wadsleyite, followed by back-transformation to olivine after decompression. Experimental studies of transformation kinetics show that wadsleyite transforms to olivine in seconds at temperatures above ∼1200 K and in hours at temperatures between 900 and 1200 K. Thermal models of shock-melt cooling show that shock veins in Mbale cooled to 1200 K in 1 s. The shock pulse must have been shorter than ∼1 s to provide the high temperature conditions for post-shock back-transformation of wadsleyite. Many highly shocked L chondrites, which have abundant high-pressure minerals, must have experienced relatively long shock durations combined with rapid cooling of shock-melt regions to preserve high-pressure phases. The most highly shocked samples, such as impact melt breccias, lack high-pressure phases because of post-shock back-transformations.

  15. Role of echocardiography in reducing shock reversal time in pediatric septic shock: a randomized controlled trial.

    Science.gov (United States)

    El-Nawawy, Ahmed A; Abdelmohsen, Aly M; Hassouna, Hadir M

    2017-09-03

    To evaluate the role of echocardiography in reducing shock reversal time in pediatric septic shock. A prospective study conducted in the pediatric intensive care unit of a tertiary care teaching hospital from September 2013 to May 2016. Ninety septic shock patients were randomized in a 1:1 ratio for comparing the serial echocardiography-guided therapy in the study group with the standard therapy in the control group regarding clinical course, timely treatment, and outcomes. Shock reversal was significantly higher in the study group (89% vs. 67%), with significantly reduced shock reversal time (3.3 vs. 4.5 days). Pediatric intensive care unit stay in the study group was significantly shorter (8±3 vs. 14±10 days). Mortality due to unresolved shock was significantly lower in the study group. Fluid overload was significantly lower in the study group (11% vs. 44%). In the study group, inotropes were used more frequently (89% vs. 67%) and initiated earlier (12[0.5-24] vs. 24[6-72]h) with lower maximum vasopressor inotrope score (120[30-325] vs. 170[80-395]), revealing predominant use of milrinone (62% vs. 22%). Serial echocardiography provided crucial data for early recognition of septic myocardial dysfunction and hypovolemia that was not apparent on clinical assessment, allowing a timely management and resulting in shock reversal time reduction among children with septic shock. Copyright © 2017 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  16. STEMing the Shock: Examining Transfer Shock and Its Impact on STEM Major and Enrollment Persistence

    Science.gov (United States)

    Lakin, Joni M.; Cardenas Elliott, Diane

    2016-01-01

    Students who transfer between institutions of higher education often experience "transfer shock", a temporary decrease in academic performance (GPA) hypothesized to be due to changes in academic expectations between institutions. This study used university institutional records to explore the magnitude of transfer shock; the factors…

  17. Spectral features of the diffusive shock acceleration of electrons at the termination shock

    Science.gov (United States)

    Prinsloo, Phillip; Toit Strauss, Du; Potgieter, Marius

    2016-07-01

    Following the revelation that the source of the anomalous cosmic rays was, contrary to expectation, not located at the termination shock, the diffusive shock acceleration mechanism came under increased criticism. With regards to galactic cosmic rays, however, its involvement in their re-acceleration is less disputed, but the extent of this involvement had to be reaffirmed given the new parameter constraints provided by the Voyager spacecraft. Hence, the features of diffusive shock acceleration, studied in the context of the transport of galactic electrons, are investigated using a numerical cosmic-ray modulation model that makes provision for the effects of this acceleration mechanism. The imprint of diffusive shock acceleration on the energy distributions of galactic electrons arriving at the termination shock is studied, along with the interplay between this acceleration mechanism and transport processes such as drift and diffusion. An important overarching set of results is that if the energy distribution of electrons incident at the termination shock is softer than the power law associated with the shock compression ratio, the latter is adopted by the accelerated particles, while if the converse is true, the incident distribution's intensity is raised uniformly. This intensity increase is in turn dependent on how similar the incident spectrum is to the power law associated with the compression ratio. The influence of other transport processes on cosmic-ray re-acceleration hence hinges on how they alter energy distributions incident at the termination shock.

  18. Videotutor: una extensión de moodle para tutorías de Matemáticas y Ciencias Experimentales

    OpenAIRE

    Angulo Ardoy, Pablo; Guijarro Santamaría, Luis; de Llano Pato, Elisa

    2010-01-01

    En Ciencias, la tutoría personalizada es el instrumento más efectivo para la enseñanza de procedimientos de resolución de problemas. A lo largo de su carrera docente, muchos profesionales han repetido muchas veces, con pequeñas variaciones, la misma tutoría, llegando a destilar una manera efectiva de transmitir su contenido. Una reflexión sobre el aprendizaje durante la tutoría nos llevó a desarrollar una extensión de moodle, de nombre videotutor: un sistema para que los profesores creen tuto...

  19. Detonation Shock Dynamics of Composite Energetic Materials.

    Science.gov (United States)

    Lee, Jaimin

    1990-01-01

    A reaction-rate equation for a composite energetic material was calibrated from two-dimensional steady-state experiment data by using the detonation shock dynamics theory. From experimental detonation velocities and shock -front shapes at different diameters for an ammonium nitrate -based emulsion explosive at 1.248 g/cm^3, the relationship between the detonation velocity normal to the shock-front and the shock-front curvature was obtained. By using this relationship and solving the quasi one-dimensional Euler equations of motion in a problem -conforming intrinsic-coordinate frame obtained from the detonation shock dynamics theory, the reaction rate was determined as a function of pressure and density: {dlambdaover dt} = 20.0 times 10^6 {rm exp}({-}14390/ sqrt{P/rho^{0.8418}})(1 - lambda)^{1.889}where lambda is the reaction extent, t is the time in s, P is the pressure in Pa, and rho is the density in kg/m^3 . The reaction-rate equation obtained for this emulsion explosive shows that the rate is very slow and weakly state dependent. These characteristics of the rate indicated that the nonideal behavior of most industrial-type explosives can be attributed to their slow and state-insensitive rates. By using the above rate equation, one-dimensional initiation experiments (wedge tests) were numerically modeled with a one-dimensional Lagrangian hydrodynamic code. The calculated shock trajectories agreed very well with experimental wedge test data. This agreement also suggested that the small shock-curvature asymptotics may be valid even for a relatively large value of the curvature. The calibration method developed in this study is independent of the form of the rate. Realistic rate equations for explosives can be obtained in a very systematic way from two-dimensional steady-state experiments.

  20. Shock-implanted noble gases. II - Additional experimental studies and recognition in naturally shocked terrestrial materials

    Science.gov (United States)

    Bogard, Donald; Horz, Friedrich; Johnson, Pratt

    1989-01-01

    The process by which ambient gases can be implanted into silicates by shocks was investigated by analyzing the noble-gas content of several experimentally and naturally shocked silicate samples. The retentivity of shock-implanted gas during stepwise heating in the laboratory was defined in terms of two parameters, namely, the activation energy for diffusion and the extraction temperature at which 50 percent of the gas is released, both of which correlate with the shock pressure. The experiments indicate that, with increasing shock pressure, gas implantation occurs through an increasing production of microcracks/defects in the silicate lattice. The degree of annealing of these defects control the degree of diffusive loss of implanted gas.

  1. NMR spectroscopy of experimentally shocked single crystal quartz: A reexamination of the NMR shock barometer

    Science.gov (United States)

    Fiske, P. S.; Gratz, A. J.; Nellis, W. J.

    1993-01-01

    Cygan and others report a broadening of the Si-29 nuclear magnetic resonance (NMR) peak for synthetic quartz powders with increasing shock pressure which they propose as a shock wave barometer for natural systems. These results are expanded by studying single crystal quartz shocked to 12 and 33 GPa using the 6.5 m two-stage light-gas gun at Lawrence Livermore National Laboratories. Our NMR results differ substantially from those of Cygan and others and suggest that the proposed shock wave barometer may require refinement. The difference in results between this study and that of Cygan and others is most likely caused by different starting materials (single crystal vs. powder) and different shock loading histories. NMR results from single crystal studies may be more applicable to natural systems.

  2. Characterization of Saturn's bow shock: Magnetic field observations of quasi-perpendicular shocks

    CERN Document Server

    Sulaiman, A H; Dougherty, M K

    2016-01-01

    Collisionless shocks vary drastically from terrestrial to astrophysical regimes resulting in radically different characteristics. This poses two complexities. Firstly, separating the influences of these parameters on physical mechanisms such as energy dissipation. Secondly, correlating observations of shock waves over a wide range of each parameter, enough to span across different regimes. Investigating the latter has been restricted since the majority of studies on shocks at exotic regimes (such as supernova remnants) have been achieved either remotely or via simulations, but rarely by means of in-situ observations. Here we present the parameter space of MA bow shock crossings from 2004-2014 as observed by the Cassini spacecraft. We find that Saturn's bow shock exhibits characteristics akin to both terrestrial and astrophysical regimes (MA of order 100), which is principally controlled by the upstream magnetic field strength. Moreover, we determined the {\\theta}Bn of each crossing to show that Saturn's (days...

  3. Simulations of Turbulent Flows with Strong Shocks and Density Variations

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Xiaolin

    2012-12-13

    In this report, we present the research efforts made by our group at UCLA in the SciDAC project Simulations of turbulent flows with strong shocks and density variations. We use shock-fitting methodologies as an alternative to shock-capturing schemes for the problems where a well defined shock is present. In past five years, we have focused on development of high-order shock-fitting Navier-Stokes solvers for perfect gas flow and thermochemical non-equilibrium flow and simulation of shock-turbulence interaction physics for very strong shocks. Such simulation has not been possible before because the limitation of conventional shock capturing methods. The limitation of shock Mach number is removed by using our high-order shock-fitting scheme. With the help of DOE and TeraGrid/XSEDE super computing resources, we have obtained new results which show new trends of turbulence statistics behind the shock which were not known before. Moreover, we are also developing tools to consider multi-species non-equilibrium flows. The main results are in three areas: (1) development of high-order shock-fitting scheme for perfect gas flow, (2) Direct Numerical Simulation (DNS) of interaction of realistic turbulence with moderate to very strong shocks using super computing resources, and (3) development and implementation of models for computation of mutli-species non-quilibrium flows with shock-fitting codes.

  4. Analytical model for fast-shock ignition

    Directory of Open Access Journals (Sweden)

    S. A. Ghasemi

    2014-07-01

    Full Text Available A model and its improvements are introduced for a recently proposed approach to inertial confinement fusion, called fast-shock ignition (FSI. The analysis is based upon the gain models of fast ignition, shock ignition and considerations for the fast electrons penetration into the pre-compressed fuel to examine the formation of an effective central hot spot. Calculations of fast electrons penetration into the dense fuel show that if the initial electron kinetic energy is of the order ∼4.5 MeV, the electrons effectively reach the central part of the fuel. To evaluate more realistically the performance of FSI approach, we have used a quasi-two temperature electron energy distribution function of Strozzi (2012 and fast ignitor energy formula of Bellei (2013 that are consistent with 3D PIC simulations for different values of fast ignitor laser wavelength and coupling efficiency. The general advantages of fast-shock ignition in comparison with the shock ignition can be estimated to be better than 1.3 and it is seen that the best results can be obtained for the fuel mass around 1.5 mg, fast ignitor laser wavelength ∼0.3  micron and the shock ignitor energy weight factor about 0.25.

  5. Pathophysiological roles of peroxynitrite in circulatory shock.

    Science.gov (United States)

    Szabó, Csaba; Módis, Katalin

    2010-09-01

    Peroxynitrite is a reactive oxidant produced from nitric oxide and superoxide, which reacts with proteins, lipids, and DNA, and promotes cytotoxic and proinflammatory responses. Here, we overview the role of peroxynitrite in various forms of circulatory shock. Immunohistochemical and biochemical evidences demonstrate the production of peroxynitrite in various experimental models of endotoxic and hemorrhagic shock both in rodents and in large animals. In addition, biological markers of peroxynitrite have been identified in human tissues after circulatory shock. Peroxynitrite can initiate toxic oxidative reactions in vitro and in vivo. Initiation of lipid peroxidation, direct inhibition of mitochondrial respiratory chain enzymes, inactivation of glyceraldehyde-3-phosphate dehydrogenase, inhibition of membrane Na+/K+ ATPase activity, inactivation of membrane sodium channels, and other oxidative protein modifications contribute to the cytotoxic effect of peroxynitrite. In addition, peroxynitrite is a potent trigger of DNA strand breakage, with subsequent activation of the nuclear enzyme poly(ADP-ribose) polymerase, which promotes cellular energetic collapse and cellular necrosis. Additional actions of peroxynitrite that contribute to the pathogenesis of shock include inactivation of catecholamines and catecholamine receptors (leading to vascular failure) and endothelial and epithelial injury (leading to endothelial and epithelial hyperpermeability and barrier dysfunction), as well as myocyte injury (contributing to loss of cardiac contractile function). Neutralization of peroxynitrite with potent peroxynitrite decomposition catalysts provides cytoprotective and beneficial effects in rodent and large-animal models of circulatory shock.

  6. Predictive modeling of a radiative shock system

    Energy Technology Data Exchange (ETDEWEB)

    Holloway, James Paul, E-mail: hagar@umich.edu [Department of Nuclear Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Bingham, Derek [Statistics and Actuarial Science, Simon Fraser University, Burnaby, BC, V5A 1S6 (Canada); Chou, Chuan-Chih; Doss, Forrest; Paul Drake, R.; Fryxell, Bruce; Grosskopf, Michael; Holst, Bart van der [Atmospheric Oceanic and Space Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Mallick, Bani K. [Department of Statistics, Texas A and M University, College Station, TX 77843-3143 (United States); McClarren, Ryan [Institute for Applied Mathematics and Computational Science, Texas A and M University, College Station, TX 77843-3133 (United States); Mukherjee, Ashin; Nair, Vijay [Department of Statistics, University of Michigan, Ann Arbor, MI 48109 (United States); Powell, Kenneth G. [Department of Aerospace Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Ryu, D. [Department of Statistics, Texas A and M University, College Station, TX 77843-3143 (United States); Sokolov, Igor; Toth, Gabor [Atmospheric Oceanic and Space Sciences, University of Michigan, Ann Arbor, MI 48109 (United States); Zhang Zhanyang [Department of Statistics, University of Michigan, Ann Arbor, MI 48109 (United States)

    2011-09-15

    A predictive model is constructed for a radiative shock experiment, using a combination of a physics code and experimental measurements. The CRASH code can model the radiation hydrodynamics of the radiative shock launched by the ablation of a Be drive disk and driven down a tube filled with Xe. The code is initialized by a preprocessor that uses data from the Hyades code to model the initial 1.3 ns of the system evolution, with this data fit over seven input parameters by a Gaussian process model. The CRASH code output for shock location from 320 simulations is modeled by another Gaussian process model that combines the simulation data with eight field measurements of a CRASH experiment, and uses this joint model to construct a posterior distribution for the physical parameters of the simulation (model calibration). This model can then be used to explore sensitivity of the system to the input parameters. Comparison of the predicted shock locations in a set of leave-one-out exercises shows that the calibrated model can predict the shock location within experimental uncertainty.

  7. Constitutive modeling of shock response of PTFE

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Eric N [Los Alamos National Laboratory; Reanyansky, Anatoly D [DSTO, AUSTRALIA; Bourne, Neil K [AWE, UK; Millett, Jeremy C F [AWE, UK

    2009-01-01

    The PTFE (polytetrafluoroethylene) material is complex and attracts attention of the shock physics researchers because it has amorphous and crystalline components. In turn, the crystalline component has four known phases with the high pressure transition to phase III. At the same time, as has been recently studied using spectrometry, the crystalline region is growing with load. Stress and velocity shock-wave profiles acquired recently with embedded gauges demonstrate feature that may be related to impedance mismatches between the regions subjected to some transitions resulting in density and modulus variations. We consider the above mentioned amorphous-to-crystalline transition and the high pressure Phase II-to-III transitions as possible candidates for the analysis. The present work utilizes a multi-phase rate sensitive model to describe shock response of the PTFE material. One-dimensional experimental shock wave profiles are compared with calculated profiles with the kinetics describing the transitions. The objective of this study is to understand the role of the various transitions in the shock response of PTFE.

  8. Dopamine versus noradrenaline in septic shock

    Directory of Open Access Journals (Sweden)

    Bo Xu

    2011-10-01

    Full Text Available BackgroundThe ‘Surviving Sepsis’ Campaign guidelines recommend theuse of dopamine or noradrenaline as the first vasopressor inseptic shock. However, information that guides clinicians inchoosing between dopamine and noradrenaline as the firstvasopressor in patients with septic shock is limited.ObjectiveThis article presents a review of the literature regarding theuse of dopamine versus noradrenaline in patients with septicshock.ResultsTwo randomised controlled trials (RCT and two largeprospective cohort studies were analysed. RCT data showeddopamine was associated with increased arrhythmic events.One cohort study found dopamine was associated with higher30-day mortality. The other cohort study found noradrenalinewas associated with higher 28-day mortality.DiscussionData on the use of dopamine versus noradrenaline in patientswith septic shock is limited. Following the recent SOAP IIstudy, there is now strong evidence that the use of dopaminein septic shock is associated with significantly morecardiovascular adverse events, compared tonoradrenaline.ConclusionNoradrenaline should be used as the initial vasopressor inseptic shock to avoid the arrhythmic events associatedwith dopamine.

  9. Modeling the Shock Hugoniot in Porous Materials

    Science.gov (United States)

    Cochrane, Kyle R.; Shulenburger, Luke; Mattsson, Thomas R.; Lane, J. Matthew D.; Weck, Philippe F.; Vogler, Tracy J.; Desjarlais, Michael P.

    2017-06-01

    Porous materials are present in many scenarios from planetary science to ICF. Understanding how porosity modifies the behavior of the shock Hugoniot in an equation of state is key to being able to predictively simulate experiments. For example, modeling shocks in under-dense iron oxide can aid in understanding planetary formation and silica aerogel can be used to approximate the shock response of deuterium. Simulating the shock response of porous materials presents a variety of theoretical challenges, but by combining ab initio calculations with a surface energy and porosity model, we are able to accurately represent the shock Hugoniot. Finally, we show that this new approach can be used to calculate the Hugoniot of porous materials using existing tabular equations of state. Sandia National Laboratories is a multi-mission laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  10. Studies of plastic insulators under shock conditions

    Energy Technology Data Exchange (ETDEWEB)

    Oona, H. (Henn); Goforth, J. H. (James H.); Tasker, D. G. (Douglas G.); King, J. C. (James Carrel); Sena, F. C. (Francis C.); Kiuttu, G.; Casvassos, T.

    2001-01-01

    As experiments done with explosively driven switches and magnetic flux compression generators become complex, the details become increasingly important. In most experiments the detonation of explosives is done through hyers of material that include metal and plastic, which may retard the detonation, and at the same time the insulating materials must maintain their integrity at high voltages. We have initiated some small-scale experiments that use a few hundred grams of explosives to study effects on shocked materials. These studies look at effects on detonation through various materials as a function of their thickness, and will be compared with hydrodynamic computer modeling done with the MESA2D code. Another related series of experiments observed the voltage breakdown o f insulators under shock conditions. In this set of experiments insulators made of polyethylene, Teflon and Mylar were placed between two electrodes and exposed to 12OKV during a shock. The timing of the shock was determined from light produced at a flash gap. Photo-diodes coupled to optical fibers were used to transmit the signals to the diagnostic bunker. A Pearson probe was used to monitor the voltage at the insulator during the breakdown. The timing of the breakdown relative to the shock arrival time was recorded. The breakdown data as a function of materials and geometry are provided in this report. Also, these data are compared with computer simulations that may suggest material conditions at the time of insulator failure.

  11. Observation and control of shock waves in individual nanoplasmas.

    Science.gov (United States)

    Hickstein, Daniel D; Dollar, Franklin; Gaffney, Jim A; Foord, Mark E; Petrov, George M; Palm, Brett B; Keister, K Ellen; Ellis, Jennifer L; Ding, Chengyuan; Libby, Stephen B; Jimenez, Jose L; Kapteyn, Henry C; Murnane, Margaret M; Xiong, Wei

    2014-03-21

    Using an apparatus that images the momentum distribution of individual, isolated 100-nm-scale plasmas, we make the first experimental observation of shock waves in nanoplasmas. We demonstrate that the introduction of a heating pulse prior to the main laser pulse increases the intensity of the shock wave, producing a strong burst of quasimonoenergetic ions with an energy spread of less than 15%. Numerical hydrodynamic calculations confirm the appearance of accelerating shock waves and provide a mechanism for the generation and control of these shock waves. This observation of distinct shock waves in dense plasmas enables the control, study, and exploitation of nanoscale shock phenomena with tabletop-scale lasers.

  12. Influencia del contenido graso y de otras variables sobre la capacidad de fusión del queso Cremoso Argentino

    Directory of Open Access Journals (Sweden)

    Zalazar, Carlos A.

    2004-09-01

    Full Text Available The influence of the fat content, pH, the ripening degree and the incorporation of whey proteins, by two different methods, on the meltability of Cremoso Argentino cheese was examined. Different experimental cheeses were made at pilot plant scale and their meltabilities were determined by a modified Schreiber test. Ripening degree and fat content showed a good correlation with the meltability. Though, cheeses with incorporation of whey proteins showed poor meltability, despite their yields increased. No correlation was found between pH and meltability inside the pH working range studied.En el presente trabajo se estudió la influencia del contenido de materia grasa, pH, grado de maduración e incorporación de proteínas de suero mediante dos vías diferentes sobre la capacidad de fusión del queso Cremoso Argentino. Utilizando una técnica modificada del test de Schreiber se analizó la capacidad de fusión de distintos quesos experimentales elaborados a escala piloto. El contenido graso y el grado de maduración afectaron positivamente la capacidad de fusión. La incorporación de proteínas de suero produjo mayores rendimientos pero la capacidad de fusión se vio fuertemente disminuida. No se observó una influencia clara del pH dentro de los límites estudiados

  13. INFLUENCIA DE LA BACTERIA Pseudomonas fluorescens EN LA LECHE, SOBRE LAS CARACTERÍSTICAS SENSORIALES DEL QUESO DOBLE CREMA

    Directory of Open Access Journals (Sweden)

    SJ González

    2007-01-01

    Full Text Available El objetivo de este trabajo fue observar el efecto de la presencia de microorganismos psicro-tróÀcos en la leche, sobre las características sensoriales del queso doble crema. Para esto, se inoculó la leche con un cultivo de Pseudomonas Áuorescens, a un nivel de 108 unidades formadoras de colonia por mililitro (ufc/ml. La leche se refrigeró a 4 ºC por seis días, se pasteurizó y posteriormente se preparó el queso. Se elaboraron lotes de queso cada 10 días, con el Àn de obtener siete tiempos experimentales. A cada uno se le determinó la vida útil sensorial. Los resultados de las pruebas sensoriales se analizaron con el programa S-PLUS de estadísti-ca de supervivencia aplicada a la vida útil sensorial de alimentos. Se determinó que el tiempo de vida útil sensorial del queso doble crema elaborado con leche en estas condiciones, y alma-cenado a 4 °C, está alrededor de 30 días, disminuyendo en un 50% con relación al patrón.

  14. INFLUENCIA DE LA COMPOSICION DE LA LECHE EN POLVO SOBRE LA ACTIVIDAD DE AGUA APLICANDO EL MODELO DE GAB

    Directory of Open Access Journals (Sweden)

    Julio Gil

    2016-01-01

    Full Text Available El presente trabajo, mediante el estudio de las isotermas de sorción a 25ºC, analiza la influencia sobre la actividad de agua (aw, de las diferentes composiciones de leche en polvo entera, descremada y reducida en lactosa. Justamente la incorporación de esta última a trabajos anteriores permite ampliar el comportamiento diferencial de los distintos componentes. E l trabajo permite establecer la relación entre el contenido de humedad de las leches en polvo estudiadas, con su actividad de agua (aw. Los resultados experimentales son evaluados con el modelo referencial de GAB , observando que el trazado de las isotermas y los parámetros del modelo se ajustan satisfactoriamente a los valores obtenidos . Se obser va la clara influencia de la presencia de los monosacáridos (glucosa y galactosa en la leche reducida en lactosa, que disminuyen la actividad a valores mayores a 0 . 4, debido a la mayor solubilidad de estos. El contenido graso en la leche entera, al no ser adsorbente se manifiesta en valores mayores para la actividad de agua.

  15. Sobre Humanismo y Medicina

    Directory of Open Access Journals (Sweden)

    Adolfo de Francisco Zea

    2000-12-01

    Full Text Available

    En esta disertación sobre “Humanismo y Medicina”, título del libro que tuve ocasión de publicar hace un par de años, destacaré algunas de las relaciones que existen entre la medicina y las bellas artes, concretamente la música y la pintura. La Medicina tiene como objeto de su acción al Hombre. Definida como la ciencia y el arte de prevenir, curar o aliviar la enfermedad, no tiene como meta la simple prolongación de la vida biológica.

    Su tarea consiste en postergar la muerte, prevenir o reducir los padecimientos y las deformidades, curar las enfermedades, ampliar las capacidades biológicas y psicológicas de los seres humanos y ocuparse de los sufrimientos de las personas. Para Tristam Engelhardt, es la Medicina de las personas.

    Se concibe a la persona humana como el individuo de conciencia reflexiva normal que es a la vez miembro pleno de la comunidad, con los deberes y derechos que presuponen su pertenencia a ella. A esta acepción de carácter moral de la persona humana, que corresponde a lo que se llama persona “en sentido estricto”, se agrega la acepción social, que hace relación con aquellas personas a las que se otorgan prácticamente los mismos derechos, como es el caso de los niños, de los individuos que perdieron el carácter de personas por padecer de lesiones cerebrales o demencia, y de aquellos que nunca llegarán a serlo como los retrasados mentales profundos.

    Al sostener que no todos los seres humanos son personas “en sentido estricto”, la Bioética que expone Engelhardt impone, sin embargo, como obligación moral, tratar a estos últimos con pleno respeto y comprensión. Lo que es importante acerca de nosotros mismos como seres humanos, es el hecho real de que seamos personas; no simplemente nuestra pertenencia al género Horno sapiens como tal.

    Para Víctor Frankl, la persona humana es de carácter espiritual y en tal virtud, es diferente del organismo psicofísico cuya

  16. Historicismo: notas sobre um paradigma

    National Research Council Canada - National Science Library

    José D’Assunção Barros

    2012-01-01

    Este artigo tem por objetivo desenvolver algumas considerações sobre o Historicismo e sua possibilidade de ser examinado como um dos paradigmas que concorrem para o estabelecimento de uma história científica no século XIX...

  17. Passive Shock Isolation Utilising Dry Friction

    Directory of Open Access Journals (Sweden)

    Mohd Ikmal Ismail

    2017-01-01

    Full Text Available A novel shock isolation strategy for base excited system is presented by introducing a two-degree-of-freedom model with passive friction, where the friction is applied to an attached mass instead of directly to the primary isolated mass. The model is evaluated against the benchmark case of single-degree-of-freedom system with friction applied directly to the primary isolated mass. The performances of the models are compared in terms of the maximum displacement response and the acceleration during the application of the shock input for the case when the shock input duration is approximately equal to the natural period of the system (amplification region. From the results, the two-degree-of-freedom model can produce both maximum displacement reduction and smoother acceleration at the point of motion transition. An experimental rig was built to validate the theoretical results against the experimental results; it is found that the experimental results closely match the theoretical predictions.

  18. International Shock-Wave Database: Current Status

    Science.gov (United States)

    Levashov, Pavel

    2013-06-01

    Shock-wave and related dynamic material response data serve for calibrating, validating, and improving material models over very broad regions of the pressure-temperature-density phase space. Since the middle of the 20th century vast amount of shock-wave experimental information has been obtained. To systemize it a number of compendiums of shock-wave data has been issued by LLNL, LANL (USA), CEA (France), IPCP and VNIIEF (Russia). In mid-90th the drawbacks of the paper handbooks became obvious, so the first version of the online shock-wave database appeared in 1997 (http://www.ficp.ac.ru/rusbank). It includes approximately 20000 experimental points on shock compression, adiabatic expansion, measurements of sound velocity behind the shock front and free-surface-velocity for more than 650 substances. This is still a useful tool for the shock-wave community, but it has a number of serious disadvantages which can't be easily eliminated: (i) very simple data format for points and references; (ii) minimalistic user interface for data addition; (iii) absence of history of changes; (iv) bad feedback from users. The new International Shock-Wave database (ISWdb) is intended to solve these and some other problems. The ISWdb project objectives are: (i) to develop a database on thermodynamic and mechanical properties of materials under conditions of shock-wave and other dynamic loadings, selected related quantities of interest, and the meta-data that describes the provenance of the measurements and material models; and (ii) to make this database available internationally through the Internet, in an interactive form. The development and operation of the ISWdb is guided by an advisory committee. The database will be installed on two mirrored web-servers, one in Russia and the other in USA (currently only one server is available). The database provides access to original experimental data on shock compression, non-shock dynamic loadings, isentropic expansion, measurements of sound

  19. Shock Scattering in a Multiphase Flow Model

    Energy Technology Data Exchange (ETDEWEB)

    Klem, D

    2003-04-08

    Multiphase flow models have been proposed for use in situations which have combined Rayleigh-Taylor (RTI) and Richtmyer-Meshkov (RMI) instabilities. Such an approach work poorly for the case of a heavy to light shock incidence on a developed interface. The physical original of this difficulty is traced to an inadequate model of the interfacial pressure term as it appears in the momentum and turbulence kinetic energy equations. Constraints on the form of a better model from a variety of sources are considered. In this context it is observed that a new constraint on closures arises. This occurs because of the discontinuity within the shock responsible for the RMI. The proposed model (Shock Scattering) is shown to give useful results.

  20. A model for shock wave chaos

    Science.gov (United States)

    Faria, Luiz; Kasimov, Aslan; Rosales, Rodolfo

    2012-11-01

    We propose the following simple model equation that describes chaotic shock waves: ut +1/2 (u2 -uus)x = f (x ,us) . It is given on the half-line x = 0 . Here us(t) is the shock state and f is a given source term [1]. The equation is a modification of the Burgers equation that includes non-locality via the presence of the shock-state value of the solution in the equation itself. The model predicts steady-state solutions, their instability through a Hopf bifurcation, and a sequence of period-doubling bifurcations leading to chaos. This dynamics is similar to that observed in the one-dimensional reactive Euler equations that describe detonations. We present nonlinear numerical simulations as well as a complete linear stability theory for the equation. Supported by DMS-0907955 and KAUST Office of Competitive Research Grants.

  1. The Cocoon Shock of Cygnus A

    Science.gov (United States)

    Snios, Bradford; Kraft, Ralph P.; Nulsen, Paul; Wise, Michael W.

    2017-08-01

    Cygnus A is an archetype FRII radio galaxy and is the nearest powerful radio galaxy in the Universe. It is hosted by the central galaxy of a rich cluster, and X-ray observations of the system provide a unique opportunity to investigate the physical structure of a powerful radio galaxy as well as the galaxy's impact on the cluster host. My talk will cover our analysis of the recent deep exposure Chandra observations of Cygnus A's cocoon shock. The observational data is fitted with multiple models to assess the speed and strength of the cocoon shock to high accuracy. The results show that the shocked gas is driven with a generally uniform pressure, although a pressure difference of 30% is seen between the radio lobes. I will discuss implications of these findings on both the radio jet properties and the jet's interactions with its cluster atmosphere.

  2. Shock Wave Structure in Particulate Composites

    Science.gov (United States)

    Rauls, Michael; Ravichandran, Guruswami

    2015-06-01

    Shock wave experiments are conducted on a particulate composite consisting of a polymethyl methacrylate (PMMA) matrix reinforced by glass beads. Such a composite with an impedance mismatch of 4.3 closely mimics heterogeneous solids of interest such as concrete and energetic materials. The composite samples are prepared using a compression molding process. The structure and particle velocity rise times of the shocks are examined using forward ballistic experiments. Reverse ballistic experiments are used to track how the interface density influences velocity overshoot above the steady state particle velocity. The effects of particle size (0.1 to 1 mm) and volume fraction of glass beads (30-40%) on the structure of the leading shock wave are investigated. It is observed that the rise time increases with increasing particle size and scales linearly for the range of particle sizes considered here. Results from numerical simulations using CTH are compared with experimental results to gain insights into wave propagation in heterogeneous particulate composites.

  3. Shock wave science and technology reference library

    CERN Document Server

    2009-01-01

    This book is the second of several volumes on solids in the Shock Wave Science and Technology Reference Library. These volumes are primarily concerned with high-pressure shock waves in solid media, including detonation and high-velocity impact and penetration events. Of the four extensive chapters in this volume, the first two describe the reactive behavior of condensed phase explosives, - Condensed-Phase Explosives: Shock Initiation and Detonation Phenomena (SA Sheffield and R Engelke) - First Principles Molecular Simulations of Energetic Materials at High-Pressures (F Zhang, S Alavi, and TK Woo), and the remaining two discuss the inert, mechanical response of solid materials. - Combined Compression and Shear Plane Waves (ZP Tang and JB Aidun), and - Dynamic Fragmentation of Solids (D Grady). All chapters are each self-contained, and can be read independently of each other. They offer a timely reference, for beginners as well as professional scientists and engineers, on the foundations of detonation phenomen...

  4. Time resolved spectroscopy of shock compressed liquids

    Science.gov (United States)

    Ogilvie, K.; Duvall, G. E.

    1982-04-01

    An experimental procedure has been developed for using a rotating mirror camera to record time-resolved absorption spectra of liquids undergoing shock compression. Experimental records have been obtained for cells containing liquid carbon disulfide shocked, through reverberation, to peak pressures of 55, 80, 100 and 120 kbar. Experiments have been performed using both reflected and transmitted light. Time and spectral resolution were limited to approximately 30 nsec and 30 Å; spectral range was from 4000 to 2500 Å. This initial work on carbon disulfide shows it to become highly absorptive when shocked to low pressures of 8 to 14 kbar, and to progressively become a better broadband reflector as the pressure in a thin layer rings up to the final value. A decay in the reflectivity after reaching peak pressure in the 120 kbar experiment may indicate chemical decomposition. This is in accord with earlier results of S. A. Sheffield based on measurement of flow parameters.

  5. Shear Shock Waves Observed in the Brain

    Science.gov (United States)

    Espíndola, David; Lee, Stephen; Pinton, Gianmarco

    2017-10-01

    The internal deformation of the brain is far more complex than the rigid motion of the skull. An ultrasound imaging technique that we have developed has a combination of penetration, frame-rate, and motion-detection accuracy required to directly observe the formation and evolution of shear shock waves in the brain. Experiments at low impacts on the traumatic-brain-injury scale demonstrate that they are spontaneously generated and propagate within the porcine brain. Compared to the initially smooth impact, the acceleration at the shock front is amplified up to a factor of 8.5. This highly localized increase in acceleration suggests that shear shock waves are a previously unappreciated mechanism that could play a significant role in traumatic brain injury.

  6. Shock Tube as an Impulsive Application Device

    Directory of Open Access Journals (Sweden)

    Soumya Ranjan Nanda

    2017-01-01

    Full Text Available Current investigations solely focus on application of an impulse facility in diverse area of high-speed aerodynamics and structural mechanics. Shock tube, the fundamental impulse facility, is specially designed and calibrated for present objectives. Force measurement experiments are performed on a hemispherical test model integrated with the stress wave force balance. Similar test model is considered for heat transfer measurements using coaxial thermocouple. Force and heat transfer experiments demonstrated that the strain gauge and thermocouple have lag time of 11.5 and 9 microseconds, respectively. Response time of these sensors in measuring the peak load is also measured successfully using shock tube facility. As an outcome, these sensors are found to be suitable for impulse testing. Lastly, the response of aluminum plates subjected to impulsive loading is analyzed by measuring the in-plane strain produced during deformation. Thus, possibility of forming tests in shock is also confirmed.

  7. Improving adherence to PALS septic shock guidelines.

    Science.gov (United States)

    Paul, Raina; Melendez, Elliot; Stack, Anne; Capraro, Andrew; Monuteaux, Michael; Neuman, Mark I

    2014-05-01

    Few studies have demonstrated improvement in adherence to Pediatric Advanced Life Support guidelines for severe sepsis and septic shock. We sought to improve adherence to national guidelines for children with septic shock in a pediatric emergency department with poor guideline adherence. Prospective cohort study of children presenting to a tertiary care pediatric emergency department with septic shock. Quality improvement (QI) interventions, including repeated plan-do-study-act cycles, were used to improve adherence to a 5-component sepsis bundle, including timely (1) recognition of septic shock, (2) vascular access, (3) administration of intravenous (IV) fluid, (4) antibiotics, and (5) vasoactive agents. The intervention focused on IV fluid delivery as a key driver impacting bundle adherence, and adherence was measured using statistical process control methodology. Two-hundred forty-two patients were included: 126 subjects before the intervention (November 2009 to March 2011), and 116 patients during the QI intervention (October 2011 to May 2013). We achieved 100% adherence for all metrics, including (1) administration of 60 mL/kg IV fluid within 60 minutes (increased from baseline adherence rate of 37%), (2) administration of vasoactive agents within 60 minutes (baseline rate of 35%), and (3) 5-component bundle adherence (baseline rate of 19%). Improvement was sustained over 9 months. The number of septic shock cases between each death from this condition increased after implementation of the QI intervention. Using QI methodology, we have demonstrated improved adherence to national guidelines for severe sepsis and septic shock. Copyright © 2014 by the American Academy of Pediatrics.

  8. Curved Radio Spectra of Weak Cluster Shocks

    Science.gov (United States)

    Kang, Hyesung; Ryu, Dongsu

    2015-08-01

    In order to understand certain observed features of arc-like giant radio relics such as the rareness, uniform surface brightness, and curved integrated spectra, we explore a diffusive shock acceleration (DSA) model for radio relics in which a spherical shock impinges on a magnetized cloud containing fossil relativistic electrons. Toward this end, we perform DSA simulations of spherical shocks with the parameters relevant for the Sausage radio relic in cluster CIZA J2242.8+5301, and calculate the ensuing radio synchrotron emission from re-accelerated electrons. Three types of fossil electron populations are considered: a delta-function like population with the shock injection momentum, a power-law distribution, and a power law with an exponential cutoff. The surface brightness profile of the radio-emitting postshock region and the volume-integrated radio spectrum are calculated and compared with observations. We find that the observed width of the Sausage relic can be explained reasonably well by shocks with speed {u}{{s}}˜ 3× {10}3 {km} {{{s}}}-1 and sonic Mach number {M}{{s}}˜ 3. These shocks produce curved radio spectra that steepen gradually over (0.1-10){ν }{br} with a break frequency {ν }{br}˜ 1 GHz if the duration of electron acceleration is ˜60-80 Myr. However, the abrupt increase in the spectral index above ˜1.5 GHz observed in the Sausage relic seems to indicate that additional physical processes, other than radiative losses, operate for electrons with {γ }{{e}}≳ {10}4.

  9. Relationship of Extreme Cold Weather and Implantable Cardioverter Defibrillator Shocks.

    Science.gov (United States)

    Cloutier, Justin M; Liu, Shuangbo; Hiebert, Brett; Tam, James W; Seifer, Colette M

    2017-09-15

    Cold weather to 0°C has been implicated as a risk factor for ventricular arrhythmias and implantable cardioverter defibrillator (ICD) shocks. The effect of more extreme cold weather on the risk of ventricular arrhythmias and ICD shocks is unknown. We sought to describe the relationship between extreme cold weather and the risk of ICD shocks. We retrospectively identified patients seen at the Pacemaker and Defibrillator Clinic at St. Boniface Hospital in Winnipeg, Manitoba, Canada between 2010 and 2015 with an ICD shock. We excluded multiple shocks occurring on the same day in a single patient. We collected weather data, and evaluated the relationship between ICD shocks and weather on the same day as the shock using Negative Binomial regression. Three hundred and sixty patients experienced a total of 1,355 shocks. When excluding multiple shocks occurring in a single patient on the same day, there were 756 unique shocks. The daily high (DH) was the strongest predictor of receiving an ICD shock. Compared with the warmest days (DH above 10°C), shocks were 25% more common on the coldest days (DH below -10°C), and 8% more common on cold days (DH between -10°C and 10°C). This linear trend was statistically significant, with a p-value of 0.04. In conclusion, we found an association between extreme cold weather and ICD shocks. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Efficacy of transthoracic cardioversion of atrial fibrillation using a biphasic, truncated exponential shock waveform at variable initial shock energies.

    Science.gov (United States)

    Rashba, Eric J; Gold, Michael R; Crawford, Fred A; Leman, Robert B; Peters, Robert W; Shorofsky, Stephen R

    2004-12-15

    Biphasic shocks are more effective than damped sine wave monophasic shocks for transthoracic cardioversion (CV) of atrial fibrillation (AF), but the optimal protocol for CV with biphasic shocks has not been defined. We conducted a prospective, randomized study of 120 consecutive patients with persistent AF to delineate the dose-response curve for CV of AF with a biphasic truncated exponential shock waveform and to identify clinical predictors of shock efficacy. Our data suggest that the initial shock energy for CV with this waveform should be 200 J if the patient weighs /=90 kg.

  11. THE ROLE OF PICKUP IONS ON THE STRUCTURE OF THE VENUSIAN BOW SHOCK AND ITS IMPLICATIONS FOR THE TERMINATION SHOCK

    Energy Technology Data Exchange (ETDEWEB)

    Lu Quanming; Shan Lican; Zhang Tielong; Wu Mingyu; Wang Shui [CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Science, University of Science and Technology of China, Hefei 230026 (China); Zank, Gary P. [Center for Space Plasma and Aeronomic Research (CSPAR), University of Alabama in Huntsville, Huntsville, AL 35899 (United States); Yang Zhongwei [SOA Key Laboratory for Polar Science, Polar Research Institute of China, Shanghai (China); Du Aimin, E-mail: qmlu@ustc.edu.cn [Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029 (China)

    2013-08-20

    The recent crossing of the termination shock by Voyager 2 has demonstrated the important role of pickup ions (PUIs) in the physics of collisionless shocks. The Venus Express (VEX) spacecraft orbits Venus in a 24 hr elliptical orbit that crosses the bow shock twice a day. VEX provides a unique opportunity to investigate the role of PUIs on the structure of collisionless shocks more generally. Using VEX observations, we find that the strength of the Venusian bow shock is weaker when solar activity is strong. We demonstrate that this surprising anti-correlation is due to PUIs mediating the Venusian bow shock.

  12. Shock-to-Detonation Transition simulations

    Energy Technology Data Exchange (ETDEWEB)

    Menikoff, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-07-14

    Shock-to-detonation transition (SDT) experiments with embedded velocity gauges provide data that can be used for both calibration and validation of high explosive (HE) burn models. Typically, a series of experiments is performed for each HE in which the initial shock pressure is varied. Here we describe a methodology for automating a series of SDT simulations and comparing numerical tracer particle velocities with the experimental gauge data. Illustrative examples are shown for PBX 9502 using the HE models implemented in the xRage ASC code at LANL.

  13. Explosive energy release in magnetic shocks

    Science.gov (United States)

    Vainshtein, S. I.; Rosner, R.; Sagdeev, R. Z.

    2002-03-01

    We show that a magnetic shock whose initial density and/or magnetic perturbation exceeds the Hugoniot limit may lead to substantial and rapid energy release in low β plasmas (such as occur in the magnetospheres of neutron stars). We illustrate this effect for a fast Magnetohydrodynamic perturbation, as well as for large density perturbations which can be naturally created in low β plasmas. Using the Riemann solution and simulations, we show that slow modes of finite magnitudes and Alfvénic perturbations can generate strong density perturbations. These perturbations develop into shocks, resulting in efficient energy release.

  14. Biophoton emission induced by heat shock.

    Directory of Open Access Journals (Sweden)

    Katsuhiro Kobayashi

    Full Text Available Ultraweak biophoton emission originates from the generation of reactive oxygen species (ROS that are produced in mitochondria as by-products of cellular respiration. In healthy cells, the concentration of ROS is minimized by a system of biological antioxidants. However, heat shock changes the equilibrium between oxidative stress and antioxidant activity, that is, a rapid rise in temperature induces biophoton emission from ROS. Although the rate and intensity of biophoton emission was observed to increase in response to elevated temperatures, pretreatment at lower high temperatures inhibited photon emission at higher temperatures. Biophoton measurements are useful for observing and evaluating heat shock.

  15. Mechanical vibration and shock analysis, sinusoidal vibration

    CERN Document Server

    Lalanne, Christian

    2014-01-01

    Everything engineers need to know about mechanical vibration and shock...in one authoritative reference work! This fully updated and revised 3rd edition addresses the entire field of mechanical vibration and shock as one of the most important types of load and stress applied to structures, machines and components in the real world. Examples include everything from the regular and predictable loads applied to turbines, motors or helicopters by the spinning of their constituent parts to the ability of buildings to withstand damage from wind loads or explosions, and the need for cars to m

  16. Calculation of a Shock Response Spectra

    Directory of Open Access Journals (Sweden)

    Jiri Tuma

    2011-11-01

    Full Text Available As it is stated in the ISO 18431-4 Standard, a Shock Response Spectrum is defined as the response to a given accelerationacting at a set of mass-damper-spring oscillators, which are adjusted to the different resonance frequencies while their resonancegains (Q-factor are equal to the same value. The maximum of the absolute value of the calculated responses as a function of theresonance frequencies compose the shock response spectrum (SRS. The paper will deal with employing Signal Analyzer, the softwarefor signal processing, for calculation of the SRS. The theory is illustrated by examples.

  17. Multiwavelength optical pyrometer for shock compression experiments.

    Science.gov (United States)

    Lyzenga, G A; Ahrens, T J

    1979-11-01

    A system for measurement of the spectral radiance of materials shocked to high pressures ( approximately 100 GPa) by impact using a light gas gun is described. Thermal radiation from the sample is sampled at six wavelength bands in the visible spectrum, and each signal is separately detected by solid-state photodiodes, and recorded with a time resolution of approximately 10 ns. Interpretation of the records in terms of temperature of transparent sample materials is discussed. Results of a series of exploratory experiments with metals are also given. Shock temperatures in the range 4000-8000 K have been reliably measured. Spectral radiance and temperatures have been determined with uncertainties of 2%.

  18. Analytical Treatment of Normal Condensation Shock

    Science.gov (United States)

    Heybey

    1947-01-01

    The condensation of water vapor in an air consequences: acquisition of heat (liberated heat vaporization; loss of mass on the part of the flowing gas (water vapor is converted to liquid); change in the specific gas constants and of the ratio k of the specific heats (caused by change of gas composition). A discontinuous change of state is therefore connected with the condensation; schlieren photographs of supersonic flows in two-dimensional Laval nozzles show two intersecting oblique shock fronts that in the case of high humidities may merge near the point of intersection into one normal shock front.

  19. Materials and structures under shock and impact

    CERN Document Server

    Bailly, Patrice

    2013-01-01

    In risk studies, engineers often have to consider the consequences of an accident leading to a shock on a construction. This can concern the impact of a ground vehicle or aircraft, or the effects of an explosion on an industrial site.This book presents a didactic approach starting with the theoretical elements of the mechanics of materials and structures, in order to develop their applications in the cases of shocks and impacts. The latter are studied on a local scale at first. They lead to stresses and strains in the form of waves propagating through the material, this movement then extending

  20. Multiple shocks, coping and welfare consequences: natural disasters and health shocks in the Indian Sundarbans.

    Science.gov (United States)

    Mazumdar, Sumit; Mazumdar, Papiya Guha; Kanjilal, Barun; Singh, Prashant Kumar

    2014-01-01

    Based on a household survey in Indian Sundarbans hit by tropical cyclone Aila in May 2009, this study tests for evidence and argues that health and climatic shocks are essentially linked forming a continuum and with exposure to a marginal one, coping mechanisms and welfare outcomes triggered in the response is significantly affected. The data for this study is based on a cross-sectional household survey carried out during June 2010. The survey was aimed to assess the impact of cyclone Aila on households and consequent coping mechanisms in three of the worst-affected blocks (a sub-district administrative unit), viz. Hingalganj, Gosaba and Patharpratima. The survey covered 809 individuals from 179 households, cross cutting age and gender. A separate module on health-seeking behaviour serves as the information source of health shocks defined as illness episodes (ambulatory or hospitalized) experienced by household members. Finding reveals that over half of the households (54%) consider that Aila has dealt a high, damaging impact on their household assets. Result further shows deterioration of health status in the period following the incidence of Aila. Finding suggests having suffered multiple shocks increases the number of adverse welfare outcomes by 55%. Whereas, suffering either from the climatic shock (33%) or the health shock (25%) alone increases such risks by a much lesser extent. The multiple-shock households face a significantly higher degree of difficulty to finance expenses arising out of health shocks, as opposed to their counterparts facing only the health shock. Further, these households are more likely to finance the expenses through informal loans and credit from acquaintances or moneylenders. This paper presented empirical evidence on how natural and health shocks mutually reinforce their resultant impact, making coping increasingly difficult and present significant risks of welfare loss, having short as well as long-run development manifestations.

  1. Attenuation of Post-Shock Increases in Brain Natriuretic Peptide with Post Shock Overdrive Pacing

    Directory of Open Access Journals (Sweden)

    Marco Budeus

    2010-03-01

    Full Text Available Background: Predischarge defibrillation threshold testing is often performed a few days after ICD implantation in order to validate defibrillation thresholds obtained at the time of implant. Ventricular fibrillation is induced with such testing and causes an increase in serum Brain Natriuretic Peptide (BNP levels. BNP is an indicator for cardiac stress. We wanted to examine the feasibility to alter the trend of BNP after predischarge testing in VVI, DDD and CRT ICD´s.Methods: We measured BNP before predischarge testing and 5, 10, 20 and 40 minutes after predischarge testing in 13 groups with each 20 patients. We evaluated patients without post shock pacing and patients with a post shock pacing frequency of 60, 70, 80, 90 and 100 bpm and a duration of 30 and 60 sec as well as a post shock pacing frequency of 80 and 90 bpm and a duration of 120 sec post shock pacing. Results: Patients without post shock pacing showed the highest BNP during the follow-up. The percentage values of BNP increased consistent significantly after 5 minutes compared with BNP before predischarge testing. The percentage values of BNP trend was significantly lower with a post shock pacing of 90 bpm and duration of 60 sec. In addition, we excluded a cardiac necrosis by predischarge testing because of similar values of myoglobin, cardiac troponin I and creatine kinase during the follow-up.Conclusions: Our results suggested that post shock pacing with 90 bpm and duration of 60 sec as the best optimized post shock pacing frequency and duration for VVI, DDD and CRT ICD´s. A reduction of cardiac stress is going to be achieved with the optimization of the post shock pacing frequency and duration.

  2. Aplicación práctica de métodos estereológicos renales en modelos animales experimentales

    OpenAIRE

    María Teresa Fernández García; Paula Núñez Martínez; Vanessa García de la Fuente; Marta Sánchez Pitiot; María del Carmen Muñiz Salgueiro; Carmen Perillán Méndez; Juan Argüelles Luis; Aurora Astudillo González

    2017-01-01

    Los riñones son órganos vitales que realizan funciones de excreción, equilibrio hidroelectrolítico y producción de hormonas. La nefrona es su unidad estructural y funcional. El número, tamaño y distribución de los componentes de la nefrona contienen información relevante sobre la función renal. La estereología es una rama de la morfometría que permite, aplicando reglas matemáticas, obtener información tridimensional de estructuras biológicas a partir de cortes microscópicos bidimensionales, s...

  3. Evaluación del efecto de un bloqueador de canales de calcio sobre el aprendizaje después de la inducción a hipoxia neonatal en ratas

    Directory of Open Access Journals (Sweden)

    Riesgo Prendes Lilia del

    2000-12-01

    Full Text Available

    Se evaluó el aprendizaje de ratas sometidas a hipoxia perinatal y el efecto sobre el mismo de la nimodipina, edemas de las alteraciones producidas sobre algunos signos de maduración. Para la inducción a hipoxia se utiliza nitrógeno 100% en ratas de 24 horas de nacidas, el aprendizaje fue evaluado con un test de evitación pasivo y el medicamento fue inyectado por vía intraperitoneal (IP. En los 4 grupos experimentales, se observaron deficiencias de aprendizaje, especialmente en los grupos de hipoxia e hipoxia  con medicamento 5 minutes después de la exposici6n a nitrógeno. Estos resultados muestran que los efectos de la hipoxia sobre el aprendizaje no  fueron disminuidos por el medicamento, principal mente administrándolo 5 minutes después y que los dan os producidos par la hipoxia perinatal no pudieron ser evidenciados en el desarrollo físico de las ratas debido a que los signos de maduración no se vieron afectados.

  4. Evaluación del efecto de un bloqueador de canales de calcio sobre el aprendizaje después de la inducción a hipoxia neonatal en ratas

    Directory of Open Access Journals (Sweden)

    Nohora Ardila

    2000-07-01

    Full Text Available Se evaluó el aprendizaje de ratas sometidas a hipoxia perinatal y el efecto sobre el mismo de la nimodipina, edemas de las alteraciones producidas sobre algunos signos de maduración. Para la inducción a hipoxia se utiliza nitrógeno 100% en ratas de 24 horas de nacidas, el aprendizaje fue evaluado con un test de evitación pasivo y el medicamento fue inyectado por vía intraperitoneal (IP. En los 4 grupos experimentales, se observaron deficiencias de aprendizaje, especialmente en los grupos de hipoxia e hipoxia  con medicamento 5 minutes después de la exposici6n a nitrógeno. Estos resultados muestran que los efectos de la hipoxia sobre el aprendizaje no  fueron disminuidos por el medicamento, principal mente administrándolo 5 minutes después y que los dan os producidos par la hipoxia perinatal no pudieron ser evidenciados en el desarrollo físico de las ratas debido a que los signos de maduración no se vieron afectados.

  5. Experimental Shock Transformation of Gypsum to Anhydrite: A New Low Pressure Regime Shock Indicator

    Science.gov (United States)

    Bell, Mary S.; Zolensky, Michael E.

    2011-01-01

    The shock behavior of gypsum is important in understanding the Cretaceous/Paleogene event and other terrestrial impacts that contain evaporite sediments in their targets (e.g., Mars Exploration Rover Spirit detected sulfate at Gusev crater, [1]). Most interest focuses on issues of devolatilization to quantify the production of SO2 to better understand its role in generating a temporary atmosphere and its effects on climate and biota [2,3]. Kondo and Ahrens [4] measured induced radiation emitted from single crystal gypsum shocked to 30 and 40 GPa. They observed greybody emission spectra corresponding to temperatures in the range of 3,000 to 4,000 K that are a factor of 2 to 10 times greater than calculated pressure-density energy equation of state temperatures (Hugoniot) and are high enough to melt gypsum. Chen et al. [5] reported results of shock experiments on anhydrite, gypsum, and mixtures of these phases with silica. Their observations indicated little or no devolatilization of anhydrite shocked to 42 GPa and that the fraction of sulfur, by mass, that degassed is approx.10(exp -2) of theoretical prediction. In another report of shock experiments on calcite, anhydrite, and gypsum, Badjukov et al. [6] observed only intensive plastic deformation in anhydrite shock loaded at 63 GPa, and gypsum converted to anhydrite when shock loaded at 56 GPa but have not experimentally shocked gypsum in a step-wise manner to constrain possible incipient transformation effects. Schmitt and Hornemann [7] shock loaded anhydrite and quartz to a peak pressure of 60 GPa and report the platy anhydrite grains were completely pseudomorphed by small crystallized anhydrite grains. However, no evidence of interaction between the two phases could be observed and they suggested that recrystallization of anhydrite grains is the result of a solid-state transformation. They concluded that significant decomposition of anhydrite requires shock pressures higher than 60 GPa. Gupta et al. [8

  6. Shock wave compression of condensed matter a primer

    CERN Document Server

    Forbes, Jerry W

    2012-01-01

    This book introduces the core concepts of the shock wave physics of condensed matter, taking a continuum mechanics approach to examine liquids and isotropic solids. The text primarily focuses on one-dimensional uniaxial compression in order to show the key features of condensed matter’s response to shock wave loading. The first four chapters are specifically designed to quickly familiarize physical scientists and engineers with how shock waves interact with other shock waves or material boundaries, as well as to allow readers to better understand shock wave literature, use basic data analysis techniques, and design simple 1-D shock wave experiments. This is achieved by first presenting the steady one-dimensional strain conservation laws using shock wave impedance matching, which insures conservation of mass, momentum and energy. Here, the initial emphasis is on the meaning of shock wave and mass velocities in a laboratory coordinate system. An overview of basic experimental techniques for measuring pressure...

  7. Evolution of the reverse shock emission from SNR 1987A

    DEFF Research Database (Denmark)

    Heng, K.; McCray, R.; Zhekov, A

    2006-01-01

    Stars: Circumstellar Matter, Shock Waves, ISM: Supernova Remnants, Stars: Supernovae: Individual: Alphanumeric: SN 1987A Udgivelsesdato: June 20......Stars: Circumstellar Matter, Shock Waves, ISM: Supernova Remnants, Stars: Supernovae: Individual: Alphanumeric: SN 1987A Udgivelsesdato: June 20...

  8. Collisionless Weibel shocks: Full formation mechanism and timing

    Energy Technology Data Exchange (ETDEWEB)

    Bret, A. [ETSI Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Instituto de Investigaciones Energéticas y Aplicaciones Industriales, Campus Universitario de Ciudad Real, 13071 Ciudad Real (Spain); Stockem, A. [GoLP/Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisbon (Portugal); Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Narayan, R. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, MS-51 Cambridge, Massachusetts 02138 (United States); Silva, L. O. [GoLP/Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, Lisbon (Portugal)

    2014-07-15

    Collisionless shocks in plasmas play an important role in space physics (Earth's bow shock) and astrophysics (supernova remnants, relativistic jets, gamma-ray bursts, high energy cosmic rays). While the formation of a fluid shock through the steepening of a large amplitude sound wave has been understood for long, there is currently no detailed picture of the mechanism responsible for the formation of a collisionless shock. We unravel the physical mechanism at work and show that an electromagnetic Weibel shock always forms when two relativistic collisionless, initially unmagnetized, plasma shells encounter. The predicted shock formation time is in good agreement with 2D and 3D particle-in-cell simulations of counterstreaming pair plasmas. By predicting the shock formation time, experimental setups aiming at producing such shocks can be optimised to favourable conditions.

  9. Collisionless shocks in space plasmas structure and accelerated particles

    CERN Document Server

    Burgess, David

    2015-01-01

    Shock waves are an important feature of solar system plasmas, from the solar corona out to the edge of the heliosphere. This engaging introduction to collisionless shocks in space plasmas presents a comprehensive review of the physics governing different types of shocks and processes of particle acceleration, from fundamental principles to current research. Motivated by observations of planetary bow shocks, interplanetary shocks and the solar wind termination shock, it emphasises the physical theory underlying these shock waves. Readers will develop an understanding of the complex interplay between particle dynamics and the electric and magnetic fields that explains the observations of in situ spacecraft. Written by renowned experts in the field, this up-to-date text is the ideal companion for both graduate students new to heliospheric physics and researchers in astrophysics who wish to apply the lessons of solar system shocks to different astrophysical environments.

  10. The Shock Wave in the ionosphere during an Earthquake

    Directory of Open Access Journals (Sweden)

    Kuznetsov Vladimir

    2016-01-01

    Full Text Available Fundamentally new model of the shock wave (SW generation in atmosphere and ionosphere during earthquake is proposed. The model proceeds from the idea of cooperative shock water crystallization in a cloud.

  11. Physics and applications with laser-induced relativistic shock waves

    National Research Council Canada - National Science Library

    S Eliezer; J M Martinez-Val; Z Henis; N Nissim; S V Pinhasi; A Ravid; M Werdiger; E Raicher

    2016-01-01

    The laser-induced relativistic shock waves are described. The shock waves can be created directly by a high irradiance laser or indirectly by a laser acceleration of a foil that collides with a second static foil...

  12. Efecto in vitro del D-002 sobre la actividad enzimática de la 5-lipoxigenasa (5-LOX

    Directory of Open Access Journals (Sweden)

    Yohani Pérez Guerra

    2012-06-01

    Full Text Available Introducción: el D-002, mezcla de seis alcoholes alifáticos primarios de alto peso molecular purificada de la cera de abejas, ha mostrado efectos antiinflamatorios, sin gastrotoxicidad secundaria, enmodelos experimentales. El tratamiento oral con D-002 reduce las concentraciones de leucotrieno B4 (LTB4 en exudados pleurales de ratas con pleuresía por carragenina, sugiriendo que podría inhibir la actividad enzimática de la 5-lipooxigenasa (5-LOX, si bien los mecanismos de la acción antiinflamatoria del D-002 no habían sido aún explorados. Objetivo: evaluar el efecto in vitro del D-002 sobre la actividad de la 5-LOX, utilizando la fracción citosólica de homogenatos de hígado de ratas. Métodos: las condiciones de ensayo utilizadas fueron las siguientes: fracción citosólica (50 µg de proteína disuelta en solución reguladora borato 0,2 mol/L (pH 9 y ácido linoleico (7,8-250 mmol/L como sustrato, ensayándose muestras paralelas incubadas con Tween-20/H2O (2 % (vehículo, muestras controles, D-002 (0,9-1 000 µg/mL o Lyprinol (500 µg/mL (sustancia de referencia. La actividad enzimática se evaluó mediante el cambio de absorbancia a 234 nm producido por la formación de dienos conjugados y medido en espectrofotómetro UV-visible. Resultados: la adición in vitro del D-002 produjo una inhibición significativa, dependiente de la dosis (r= 0,980; p< 0,001 (IC50= 95,34 µg/mL e incompetitiva de la actividad de la 5-LOX, cuya inhibición máxima (70 % se alcanzó con 500 µg/mL. Conclusiones: con este estudio se demuestra que el D-002 es capaz de inhibir la actividad enzimática de la 5-LOX, efecto que podría explicar, al menos parcialmente, su acción antiinflamatoria en modelos experimentales in vivo.

  13. Experiments on shock formation in a Q-device

    DEFF Research Database (Denmark)

    Andersen, H.K.; D'Angelo, N.; Michelsen, Poul

    1968-01-01

    For equal ion and electron temperatures, Ti = Te, Landau damping prevents shock formation. When the ratio Te/Ti is made as large as 3-4 through ion-neutral atom collisions, shock formation is observed.......For equal ion and electron temperatures, Ti = Te, Landau damping prevents shock formation. When the ratio Te/Ti is made as large as 3-4 through ion-neutral atom collisions, shock formation is observed....

  14. HIDROGENACIÓN DE FURFURAL SOBRE CATALIZADORES Ir/Nb2O5. ESTUDIO CINÉTICO

    Directory of Open Access Journals (Sweden)

    HUGO ROJAS

    2008-01-01

    Full Text Available Se estudió la cinética de hidrogenación de furfural sobre el catalizador Ir/Nb2O5 que presenta el efecto SMSI (Fuerte interacción metal soporte. Se examinaron el efecto de diferentes parámetros de reacción como concentración inicial en el rango de 0,025 a 0,1 M, presión parcial en el rango de 0,48 MPa a 0,98 Mpa, temperatura de 353 a 393 K y peso del catalizador de 0,1 a 0,4 g. Se encontró una alta selectividad hacía el alcohol insaturado, (alcohol furfurílico, que es el producto más importante de esta reacción. Solventes alcohólicos producen trazas de acetales, especialmente de 2,6 dietil-acetal. Las velocidades iniciales de la hidrogenación de furfural con respecto al estudio de la presión y concentración se incrementaron linealmente con la masa del catalizador, lo que demuestra la ausencia de fenómenos de transporte. La cinética de la reacción se representó con un modelo Langmuir-Hinshelwood (LH con un solo tipo de sitio activo. La adición de un átomo de hidrógeno sobre la molécula orgánica demostró ser la etapa determinante de la reacción, ajustándose a los datos experimentales.

  15. ESTUDIO DE SISTEMAS DE MEDIDA CON ENSAYOS DESTRUCTIVOS. UNA APLICACIÓN SOBRE TIEMPOS DE PRODUCCIÓN

    Directory of Open Access Journals (Sweden)

    Marta Quaglino

    2010-01-01

    Full Text Available Los estudios de repetibilidad y reproducibilidad fueron diseñados con el propósito de analizar la bondad de los sistemas de medición, análisis cuya importancia radica en el hecho que un sistema inadecuado introducirá variabilidad adicional ocasionando que las mediciones no reflejen el verdadero comportamiento del proceso. El análisis se basa en la cuantificación de la variabilidad asociada al sistema de medición y su posterior comparación con la variabilidad total observada, siendo requerimiento fundamental para ello que resulte factible obtener mediciones repetidas de una misma unidad bajo las mismas condiciones experimentales, de lo contrario, la variabilidad en las mediciones estará confundida con la variabilidad propia de las partes medidas. Tal es el caso en que los ensayos de medición son “destructivos”, esto es, las unidades no son robustas frente al proceso de medición, o bien, las unidades no son temporalmente estables.En este trabajo se exponen diversas alternativas para el caso de estudios R&R con ensayos destructivos y una aplicación particular en un problema real sobre estimación de tiempos de producción en una empresa metalúrgica. El empleo de Modelos Lineales Generalizados permitió obtener estimaciones adecuadas de ciertas Componentes de Variancia, que advirtieron sobre características importantes a mejorar en el proceso de medición.

  16. Shock-initiation chemistry of nitroarenes

    Science.gov (United States)

    Davis, Lloyd L.; Brower, Kay R.

    1998-07-01

    We present evidence that the shock-initiation chemistry of nitroarenes is dominated by the intermolecular hydrogen transfer mechanism discussed previously. The acceleration by pressure, kinetic isotope effect, and product distribution are consistent with the bimolecular transition state rather than rate-determining C-N homolysis. GC-MS analysis of samples which were subjected to a shock wave generated by detonation of nitromethane shows that nitrobenzene produces aniline and biphenyl, and o-nitrotoluene forms aniline, toluene, o-toluidine and o-cresol, but not anthranil, benzoxazinone, or cyanocyclopentadiene. In isotopic labeling experiments o-nitrotoluene and TNT show extensive H-D exchange on their methyl groups, and C-N bond rupture is not consistent with the formation of aniline from nitrobenzene or nitrotoluene, nor the formation of o-toluidine from o-nitrotoluene. Recent work incorporating fast TOF mass spectroscopy of samples shocked and quenched by adiabatic expansion indicates that the initial chemical reactions in shocked solid nitroaromatic explosives proceed along this path.

  17. Shock-initiation chemistry of nitroarenes

    Energy Technology Data Exchange (ETDEWEB)

    Davis, L.L. [Los Alamos National Lab., NM (United States); Brower, K.R. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States). Dept. of Chemistry

    1997-11-01

    The authors present evidence that the shock-initiation chemistry of nitroarenes is dominated by the intermolecular hydrogen transfer mechanism discussed previously. The acceleration by pressure, kinetic isotope effect, and product distribution are consistent with the bimolecular transition state kinetic isotope effect, and product distribution are consistent with the bimolecular transition state rather than rate-determining C-N homolysis.GC-MS analysis of samples which were subjected to a shock wave generated by detonation of nitromethane shows that nitrobenzene produces aniline and biphenyl, and o-nitrotoluene forms aniline, toluene, o-toluidine and o-cresol, but not anthranil, benzoxazinone, or cyanocyclopentandiene. In isotopic labeling experiments o-nitrotoluene and TNT show extensive H-D exchange on their methyl groups, and C-N bond rupture is not consistent with the formation of aniline from nitrobenzene or nitrotoluene, nor the formation of o-toluidine from o-nitrotoluene. Recent work incorporating fast TOF mass spectroscopy of samples shocked and quenched by adiabatic expansion shows that the initial chemical reactions in shocked solid nitroaromatic explosives proceed along this path.

  18. Shock-initiation chemistry of nitroarenes

    Energy Technology Data Exchange (ETDEWEB)

    Davis, L.L. [DX-1, Mail Stop P-952, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Brower, K.R. [Department of Chemistry, New Mexico Institute of Mining and Technology, Socorro, New Mexico 87801 (United States)

    1998-07-01

    We present evidence that the shock-initiation chemistry of nitroarenes is dominated by the intermolecular hydrogen transfer mechanism discussed previously. The acceleration by pressure, kinetic isotope effect, and product distribution are consistent with the bimolecular transition state rather than rate-determining C-N homolysis. GC-MS analysis of samples which were subjected to a shock wave generated by detonation of nitromethane shows that nitrobenzene produces aniline and biphenyl, and {ital o}-nitrotoluene forms aniline, toluene, {ital o}-toluidine and {ital o}-cresol, but not anthranil, benzoxazinone, or cyanocyclopentadiene. In isotopic labeling experiments {ital o}-nitrotoluene and TNT show extensive H-D exchange on their methyl groups, and C-N bond rupture is not consistent with the formation of aniline from nitrobenzene or nitrotoluene, nor the formation of {ital o}-toluidine from {ital o}-nitrotoluene. Recent work incorporating fast TOF mass spectroscopy of samples shocked and quenched by adiabatic expansion indicates that the initial chemical reactions in shocked solid nitroaromatic explosives proceed along this path. {copyright} {ital 1998 American Institute of Physics.}

  19. Physics of intermediate shocks: A review

    Science.gov (United States)

    Karimabadi, H.

    1995-01-01

    Intermediate shocks (ISs) lead to a transition from super-Alfvenic to sub-Alfvenic flow and are different from slow and fast shocks in that an IS rotates the component of the magnetic field tangent to the shock plane by 180 deg. Another peculiarity of ISs is that for the same upstream conditions an IS can have two different downstream states. There also exist a second class of ISs which rotate the magnetic field by an angle other than 180 deg. Due to their noncoplanar nature they cannot be time-stationary and are referred to as time-dependent intermediate shocks (TDIS). The existence of ISs has been the subject of much controversy over the years. Early studies questioned the physical reality of ISs. However, the studies of ISs found a new impetus when C.C. Wu showed that ISs do exist and are stable within the resistive MHD framework. In this paper, after a brief historical overview of the subject, we will review the latest developments in the study of ISs. In particular, we will address the questions of stability and structure of ISs and the relationship between ISs and other discontinuities. One of the recent developments has been the finding that ISs can be unsteady, reforming in time. Details of this process will be discussed. Finally, we examine the effect of anisotropy on the resolutions and discuss the relevance of ISs to the observed field rotations at the Earth's magnetopause.

  20. Shock Re-equilibration of Fluid Inclusions

    Science.gov (United States)

    Madden, M. E. Elwood; Horz, F.; Bodnar, R. J.

    2004-01-01

    Fluid inclusions (microscopic volumes of fluid trapped within minerals as they precipitate) are extremely common in terrestrial minerals formed under a wide range of geological conditions from surface evaporite deposits to kimberlite pipes. While fluid inclusions in terrestrial rocks are nearly ubiquitous, only a few fluid inclusion-bearing meteorites have been documented. The scarcity of fluid inclusions in meteoritic materials may be a result of (a) the absence of fluids when the mineral was formed on the meteorite parent body or (b) the destruction of fluid inclusions originally contained in meteoritic materials by subsequent shock metamorphism. However, the effects of impact events on pre-existing fluid inclusions trapped in target and projectile rocks has received little study. Fluid inclusions trapped prior to the shock event may be altered (re-equilibrated) or destroyed due to the high pressures, temperatures, and strain rates associated with impact events. By examining the effects of shock deformation on fluid inclusion properties and textures we may be able to better constrain the pressure-temperature path experienced by terrestrial and meteoritic shocked materials and also gain a clearer understanding of why fluid inclusions are rarely found in meteorite samples.

  1. Heat shock protein 90: the cancer chaperone

    Indian Academy of Sciences (India)

    2007-04-02

    Apr 2, 2007 ... Heat shock protein 90 (Hsp90) is a molecular chaperone required for the stability and function of a number of conditionally activated and/or expressed signalling proteins, as well as multiple mutated, chimeric, and/or over-expressed signalling proteins, that promote cancer cell growth and/or survival. Hsp90 ...

  2. Flow control for oblique shock wave reflections

    NARCIS (Netherlands)

    Giepman, R.H.M.

    2016-01-01

    Shock wave-boundary layer interactions are prevalent in many aerospace applications that involve transonic or supersonic flows. Such interactions may lead to boundary layer separation, flow unsteadiness and substantial losses in the total pressure. Flow control techniques can help to mitigate these

  3. Radiation and critical shocks in atmospheric entry

    Energy Technology Data Exchange (ETDEWEB)

    Canavan, G.H.

    1997-12-01

    Sub- and supercritical shock waves are produced during atmospheric entry. The radiation efficiency of the former increases strongly with velocity and altitude; that of the latter increases with altitude, but decreases with supercritical velocities. These efficiencies shift the region of maximum radiation one to two scale heights higher and decrease overall radiation efficiency.

  4. Success of electromagnetic shock wave lithotripter asmonotherapy ...

    African Journals Online (AJOL)

    Objectives: To evaluate the success of shock wave lithotripsy (SWL) as monotherapy for solitary renalstones larger than 2 cm without ureteral stenting. Hence, if our study result demonstrates acceptable successand safety, we can recommend ESWL as a treatment option for patients with large renal calculi. Subjects and ...

  5. Cosmic Rays Accelerated at Cosmological Shock Waves

    Indian Academy of Sciences (India)

    Based on hydrodynamic numerical simulations and diffusive shock acceleration model, we calculated the ratio of cosmic ray (CR) to thermal energy. We found that the CR fraction can be less than ∼ 0.1 in the intracluster medium, while it would be of order unity in the warm-hot intergalactic medium.

  6. Thermal shock testing of lapped optical glass

    Science.gov (United States)

    Zhang, Yingrui; Wu, Yuansun; Liu, Han; Lambropoulos, John C.

    2007-09-01

    We have measured and modeled the thermal shock fracture of the commercially available BK-7 borosilicate crown optical glass as a function of surface finish prior to thermal shock testing. For surfaces lapped with alumina abrasives in the range 5 μm to 40 μm, the critical temperature drop for fracture in thin disk samples increases with diminishing abrasive size, and changes from 123.7+/-1.1 °C (for surfaces lapped with 40 μm abrasives) to 140.2+/-2.8 °C (for surfaces lapped with 5 μm abrasives.) We correlate the measured thermal shock (critical) temperature drop with the glass thermal and mechanical properties, including the fracture toughness, and the depth of surface cracks induced by the lapping process. We distinguish between "severe" and "mild" thermal shock conditions in terms of the applicable heat transfer coefficient and Biot number. We estimate that the depth of the strength controlling cracks on the edge of the disk samples was about 55-70 μm.

  7. Shock Syntheses of Novel Nitrides and Biomolecules

    Science.gov (United States)

    Sekine, Toshimori

    2013-06-01

    High-pressure spinel nitride of Si3N4 was discovered more than 10 years ago. Since then there have been many studies on the spinel nitrides and related materials including oxynitrides. We have developed shock synthesis method to investigate their structural, mechanical, chemical, physical, and optical properties. At the same time we tried to synthesize carbon nitrides from the organic substances. And later we extended to shock synthesis of ammonia through the Haber-Bosch reaction under shock in order to apply geochemical subjects related to the origin of life. The simplest amino acid of glycine, as well as animes (up to propylamine) and carboxylic acids (up to pentanoic acid), has been synthesized successfully in aqueous solutions through meteoritic impact reactions. Recently we are trying to make more complex biomolecules for implications of biomolecule formation for the origin of life through meteorite impacts on early Earth's ocean. These results of shock syntheses may imply significant contributions to materials science and Earth and planetary sciences. This research is collaborated with National Institute for Materials Science and Tohoku University.

  8. Severe sepsis and septic shock [author's reply

    NARCIS (Netherlands)

    Angus, Derek C.; van der Poll, Tom

    2013-01-01

    To the Editor: We would like to address two potentially confusing issues concerning venous oxygen saturation (Svo(2)) as presented in Table 1 of the review by Angus and van der Poll (Aug. 29 issue).(1) First, Table 1 suggests that Svo(2) is raised in sepsis, severe sepsis, and septic shock.

  9. Critical care ultrasonography in circulatory shock

    NARCIS (Netherlands)

    Koster, Geert; van der Horst, Iwan C. C.

    Purpose of review The objective was to define the role of ultrasound in the diagnosis and the management of circulatory shock by critical appraisal of the literature.Recent findings Assessment of any patient's hemodynamic profile based on clinical examination can be sufficient in several cases, but

  10. Macroeconomic shocks and firms' labor adjustment

    DEFF Research Database (Denmark)

    Eriksson, Tor

    2013-01-01

    This article discusses some recent research which aims at producing evidence on how firms adjust their employment in response to output shocks using micro-level data and with a particular focus on the relationship between worker and job flows. The evidence presented is mainly based on Danish data...

  11. Experimental Shock Decomposition of Siderite to Magnetite

    Science.gov (United States)

    Bell, M. S.; Golden, D. C.; Zolensky, M. E.

    2005-01-01

    The debate about fossil life on Mars includes the origin of magnetites of specific sizes and habits in the siderite-rich portions of the carbonate spheres in ALH 84001 [1,2]. Specifically [2] were able to demonstrate that inorganic synthesis of these compositionally zoned spheres from aqueous solutions of variable ion-concentrations is possible. They further demonstrated the formation of magnetite from siderite upon heating at 550 C under a Mars-like CO2-rich atmosphere according to 3FeCO3 = Fe3O4 + 2CO2 + CO [3] and they postulated that the carbonates in ALH 84001 were heated to these temperatures by some shock event. The average shock pressure for ALH 84001, substantially based on the refractive index of diaplectic feldspar glasses [3,4,5] is some 35-40 GPa and associated temperatures are some 300-400 C [4]. However, some of the feldspar is melted [5], requiring local deviations from this average as high as 45-50 GPa. Indeed, [5] observes the carbonates in ALH 84001 to be melted locally, requiring pressures in excess of 60 GPa and temperatures > 600 C. Combining these shock studies with the above inorganic synthesis of zoned carbonates it seems possible to produce the ALH 84001 magnetites by the shock-induced decomposition of siderite.

  12. Magnetic field generation in relativistic shocks

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, J.; Achterberg, A. [Utrecht Univ., Utrecht (Germany). Sterrekundig Instituut

    2005-06-01

    Linear theory of the Weibel instability cannot explain magnetic field generation in relativistic shock fronts in electron-proton plasmas. The fireball model far Gamma-ray Burst afterglows requires a magnetic field in similar shock fronts between the fireball and the surrounding matter to explain the detected nonthermal afterglow radiation. We consider an analytical model of post-shock protons penetrating the hot post-shock electron plasma. The linear Weibel instability produces magnetic fields through self-enhancing current channels. Perturbations with a length-scale comparable to the electron skin depth reach the high est magnetic field before the linear theory breaks down. The electrons quench the linear proton instability so that it cannot randomize the proton velocity distribution and only converts a small fraction of the available kinetic energy of the protons into magnetic fields. We conclude that the linear Weibel instability that dominates in pair plasmas is relatively unimportant in electron-proton plasmas and that non-linear processes are probably much more important.

  13. Shock wave fabricated ceramic-metal nozzles

    NARCIS (Netherlands)

    Carton, E.P.; Stuivinga, M.E.C.; Keizers, H.L.J.; Verbeek, H.J.; Put, P.J. van der

    1999-01-01

    Shock compaction was used in the fabrication of high temperature ceramic-based materials. The materials' development was geared towards the fabrication of nozzles for rocket engines using solid propellants, for which the following metal-ceramic (cermet) materials were fabricated and tested: B4C-Ti

  14. in Cardiac Muscles of Hemorrhagic Shocked Rats

    African Journals Online (AJOL)

    Purpose: To investigate the protective effects of various resuscitating fluids on severe hemorrhagic shocked (HS) rats by comparing the expression changes of hsp90α in cardiac muscles and survival of rats. Methods: Western-blot and immunohistochemistry methods were performed to determine hsp90á expressions in ...

  15. Critical point anomalies include expansion shock waves

    NARCIS (Netherlands)

    Nannen, N.R.; Guardone, A.; Colonna, P.

    2014-01-01

    From first-principle fluid dynamics, complemented by a rigorous state equation accounting for critical anomalies, we discovered that expansion shock waves may occur in the vicinity of the liquid-vapor critical point in the two-phase region. Due to universality of near-critical thermodynamics, the

  16. Income Shocks and Adolescent Mental Health

    Science.gov (United States)

    Baird, Sarah; de Hoop, Jacobus; Ozler, Berk

    2013-01-01

    We investigate the effects of a positive income shock on mental health among adolescent girls using evidence from a cash transfer experiment in Malawi. Offers of cash transfers strongly reduced psychological distress among baseline schoolgirls. However, these large beneficial effects declined with increases in the transfer amount offered to the…

  17. Multispacecraft study of shock-flux rope interaction

    Science.gov (United States)

    Blanco-Cano, Xochitl; Burgess, David; Sundberg, Torbjorn; Kajdic, Primoz

    2017-04-01

    Interplanetary (IP) shocks can be driven in the solar wind by fast coronal mass ejections. These shocks can accelerate particles near the Sun and through the heliosphere, being associated to solar energetic particle (SEP) and energetic storm particle (ESP) events. IP shocks can interact with structures in the solar wind, and with planetary magnetospheres. In this study we show how the properties of an IP shock change when it interacts with a medium scale flux rope (FR) like structure. We use data measurements from CLUSTER, WIND and ACE. These three spacecraft observed the shock-FR interaction at different stages of its evolution. We find that the shock-FR interaction locally changes the shock geometry, affecting ion injection processes, and the upstream and downstream regions. While WIND and ACE observed a quasi-perpendicular shock, CLUSTER crossed a quasi-parallel shock and a foreshock with a variety of ion distributions. The complexity of the ion foreshock can be explained by the dynamics of the shock transitioning from quasi-perpendicular to quasi-parallel, and the geometry of the magnetic field around the flux rope. Interactions such as the one we discuss can occur often along the extended IP shock fronts, and hence their importance towards a better understanding of shock acceleration.

  18. Page 1 Shock-wave-turbulent-boundary-layer interaction & its ...

    Indian Academy of Sciences (India)

    shock .. rehabilitation shock with a turbulent boundary phase asºn: phase layer: M., + 1.47 (from Seddon. p x / So 1960). al 1977). Figures 16 and 17 show some of the important features of the separated flow and the surface pressure distributions as observed by Seddon (1960). The strong normal shock wave bifurcates near ...

  19. Interaction of Accretion Shocks with Winds Kinsuk Acharya , Sandip ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    Abstract. Accretion shocks are known to oscillate in presence of cool- ing processes in the disk. This oscillation may also cause quasi-periodic oscillations of black holes. In the presence of strong winds, these shocks have oscillations in vertical direction as well. We show examples of shock oscillations under the influence of ...

  20. Reverse Shock Emission in Gamma-Ray Bursts Revisited

    Directory of Open Access Journals (Sweden)

    He Gao

    2015-01-01

    reverse shock which have been confirmed by observations. Investigations of the nature of the reverse shock emission can provide valuable insights into the intrinsic properties of the GRB ejecta. Here we briefly review the standard and the extended models of the reverse shock emission, discussing the connection between the theory and observations, including the implications of the latest observational advances.