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Sample records for calor seco con

  1. Validación de un ciclo de despirogenización por calor seco con el empleo del ensayo del lisado de amebocitos de limulus

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    Rolando Perdomo Morales

    2003-12-01

    Full Text Available Para el cumplimiento de las buenas prácticas de laboratorio y de fabricación de parenterales, una de las exigencias es la validación de los ciclos de despirogenización que se emplean. En el presente trabajo se describe la validación de un ciclo de despirogenización por calor seco en un horno de convección. En la primera etapa se estudiaron características físicas del equipo como el tiempo requerido para alcanzar la temperatura establecida, su distribución, estabilidad, y la influencia de la carga en el patrón de calentamiento. Considerando los resultados de esta fase se estableció un proceso total de 7 h a 180 ºC. La segunda etapa consistió en la determinación del grado de despirogenización retando el proceso con bioindicadores de endotoxinas. La concentración de endotoxinas en los bioindicadores control y sometidos al proceso de despirogenización se cuantificó con el empleo del ensayo del lisado de amebocitos de limulus método de gelificación. La diferencia entre el contenido de endotoxinas en el control y los tratamientos fue de 2 400 U de endotoxinas, por lo que el proceso rindió una reducción logarítmica mínima de 4,6 log, la cual es mayor que el límite de 3 log establecido por la Farmacopea de los Estados Unidos.To fullfill the good laboratory and parenteral drugs manufacturing practices, one of the demands is the validation of the depyrogenation cycles that are used. In this paper, it is described the validation of a depyrogenation cycle by dry heat in a convection oven. The physical features of the equipment, such as the time required to reach the established temperature, its distribution, stability, and the influence of the charge on the heating pattern, were studied in the first stage. Taking into account the results of this phase, it was established a total process of 7 h at 180 °C. The second stage consisted in the determination of the degreee of depyrogenation, challenging the process with endotoxin

  2. Plantas transgénicas con alto rendimiento en peso seco y almidón cuyos órganos de reserva presentan elevada textura, elevado contenido en almidón y elevado rendimiento en peso seco

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    Pozueta Romero, Javier; Alonso Casajús, Nora; Muñoz Pérez, Francisco José; Baroja-Fernández, Edurne

    2007-01-01

    Plantas transgénicas con alto rendimiento en peso seco y almidón cuyos órganos de reserva presentan elevada textura, elevado contenido en almidón y elevado rendimiento en peso seco. La presente invención proporciona plantas transgénicas con alto rendimiento en peso seco y almidón cuyos órganos de reserva presentan elevada textura, elevado contenido en almidón y elevado rendimiento en peso seco.

  3. Poblaciones microbianas ruminales en novillas alimentadas con Leucaena leucocephala en el Bosque Seco Tropical colombiano.

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    Erika Angarita; Isabel Molina; Gonzalo Villegas; Olga Mayorga; Julián Chará; Rolando Barahona Rosales

    2015-01-01

    La fermentación y metanogénesis ruminal son procesos metabolicos vitales para los bovinos y son llevados a cabo por poblaciones microbianas, las cuales se afectan por factores como la presencia de metabolitos secundarios, la composición nutricional y la degradabilidad de la dieta. El objetivo de este trabajo fue monitorear las poblaciones de bacterias totales, metanógenos totales y Butirivibrio fibrisolvens en el rumen de novillas raza Lucerna, alimentadas con dietas típicas de un sistema sil...

  4. Research on heat pumps in Mexico operating with geothermal energy and waste heat; Investigacion sobre bombas de calor en Mexico operando con energia geotermica y calor de desecho

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Gutierrez, A; Barragan-Reyes, R.M; Arellano-Gomez, V [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: aggarcia@iie.org.mx

    2008-01-15

    The Instituto de Investigaciones Electricas and the Comision Federal de Electricidad have done research and development (R&D) on heat pumps (HP) in past years. Tested systems include mechanical compression, absorption and heat-transformers. The main R&D aspects on HP are briefly described, and also a more detailed description about three of the main studies is presented: (a) a mechanical compression HP of the water-water type operated with low-pressure geothermal steam at the Los Azufres; Mich., geothermal field, and designed for purification of brine; (b) an absorption HP for cooling and refrigeration operating with ammonia-water and low-enthalpy geothermal energy, which was tested in the Los Azufres and Cerro Prieto, BC, geothermal fields; and (c) a heat-transformer by absorption-Absorption Heat Pump Type II-tested to assess the performance of several ternary solutions as work fluids. Plans exist to install and test a geothermal heat pump at Cerro Prieto or Mexicali, BC. [Spanish] El Instituto de Investigaciones Electricas y la Comision Federal de Electricidad han realizado trabajo de investigacion y desarrollo (I&D) sobre bombas de calor (BC) en el pasado. Los sistemas probados incluyen compresion mecanica, absorcion y transformadores termicos. Este trabajo describe brevemente los principales aspectos de I&D sobre bombas de calor en forma general, y se da una descripcion mas detallada de tres de los principales estudios: (a) una BC por compresion mecanica tipo agua-agua disenada para purificacion de salmueras operando con vapor geotermico de baja presion en el campo geotermico de Los Azufres, Mich.; (b) una BC por absorcion para enfriamiento y refrigeracion operando con amoniaco-agua y energia geotermica de baja entalpia, la cual fue probada en los campos geotermicos de Los Azufres y Cerro Prieto, BC; y (c) un transformador termico por absorcion -llamado Bomba de Calor por Absorcion Tipo II--, el cual fue probado para evaluar el comportamiento de diversas

  5. REPARTICIÓN DE MICROHABITATS ENTRE ESPECIES DE BUFONIDAE Y LEIUPERIDAE (AMPHIBIA: ANURA EN ÁREAS CON BOSQUE SECO TROPICAL DE LA REGION CARIBE-COLOMBIA

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    Bonilla Gómez Maria Argenis

    2010-12-01

    Full Text Available Se analizó la repartición de microhabitats de cinco especies de anuros pertenecientes a las familias Bufonidae (Rhinella marina, R. granulosa, y Leiuperidae (Engystomops pustulosus, Pleurodema brachyops y Pseudopaludicola pusilla en seis localidades del Caribe Colombiano con fragmentos de bosque seco tropical y diferentes usos de suelo. Se identificaron 29 microhabitats. Los más usado fueron charco de agua Permanente de potreros con arboles (CPPA y potreros inundables sin árboles (PISA. La especie que mayor cantidad de microhabitats usó fue E. pustulosus. No hubo especialistas en el uso de estos ambientes. Se presentaron diferencias en el uso de este recurso a escalas regional y local. La dinámica de uso de los microhabitats estuvo influenciada por las variaciones climáticas del bosque seco tropical. Existe repartición de microhabitats como mecanismo de coexistencia en estas especies para época seca. En el periodo de lluvias este mecanismo no se aplicó.

  6. REPARTICIÓN DE MICROHABITATS ENTRE ESPECIES DE BUFONIDAE Y LEIUPERIDAE (AMPHIBIA: ANURA EN ÁREAS CON BOSQUE SECO TROPICAL DE LA REGION CARIBE-COLOMBIA

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    Argelina Blanco Torres

    2010-09-01

    Full Text Available Se analizó la repartición de microhabitats de cinco especies de anuros pertenecientes a las familias Bufonidae (Rhinella marina, R. granulosa, y Leiuperidae (Engystomops pustulosus, Pleurodema brachyops y Pseudopaludicola pusilla en seis localidades del Caribe Colombiano con fragmentos de bosque seco tropical y diferentes usos de suelo. Se identificaron 29 microhabitats. Los más usado fueron charco de agua Permanente de potreros con arboles (CPPA y potreros inundables sin árboles (PISA. La especie que mayor cantidad de microhabitats usó fue E. pustulosus. No hubo especialistas en el uso de estos ambientes. Se presentaron diferencias en el uso de este recurso a escalas regional y local. La dinámica de uso de los microhabitats estuvo influenciada por las variaciones climáticas del bosque seco tropical. Existe repartición de microhabitats como mecanismo de coexistencia en estas especies para época seca. En el periodo de lluvias este mecanismo no se aplicó.

  7. Caracterización de jamones adicionados con pastas residuales de la extracción mecánica de aceite de frutos secos

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    Juan José Luna Guevara

    2013-01-01

    Full Text Available Los frutos secos contienen en su composición nutrientes y compuestos bioactivos que al ser consumidos en cantidades suficientes aportan beneficios a la salud. En este estudio se evaluó la influencia de la adición de pastas residuales (10 %, obtenidas de la extracción de aceite de nuez de Castilla (Juglans regia L., nuez pecanera (Carya illinoinensis (Wangenh. K. Koch, variedad Western Shley, y cacahuate (Arachis hypogaea, sobre la modificación de algunas características de textura, composición proximal, fisicoquímicas, microbiológicas y sensoriales en jamones cocidos. Los jamones estudiados fueron almacenados a 4 °C durante 21 días. Las pastas adicionadas a los jamones aumentaron de manera significativa (P≤0,05 el contenido de proteína, grasa y fibra total. Los jamones adicionados con pasta presentaron estructuras menos rígidas (P≤0,05. Los parámetros de color (L*, a* y b* de los jamones mostraron una ligera disminución durante el tiempo de almacenamiento, a excepción de los adicionados con nuez de Castilla que mostraron un mayor oscurecimiento. Las pastas de frutos secos contribuyeron significativamente (P≤ 0,05 a disminuir la vida de anaquel de los jamones. Sin embargo, el recuento de mohos y levaduras en los jamones fue menor a 10 UFC/g a los 21 días de almacenamiento. La aw y el pH disminuyeron significativamente (P≤0,05 y la sinéresis aumentó durante el almacenamiento. Los jamones adicionados con pastas residuales fueron sensorialmente bien aceptados con respecto al color, olor, sabor, apariencia y aceptabilidad general.

  8. El uso de granos secos de destilería con solubles (DDGS en dietas sorgo-soya para pollos de engorda y gallinas de postura

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    Arturo Cortes Cuevas

    2012-01-01

    Full Text Available Para estudiar el comportamiento productivo en pollos y gallinas con dietas adicionadass con granos secos de destilería con solubles (DDGS, se realizaron dos experimentos. En el primero se emplearon 704 pollos Ross de 1 a 49 días de edad, distribuidos en cuatro tratamientos con ocho repeticiones de 22 pollos cada uno. Se empleó un diseño completamente al azar. Los tratamientos fueron: 1 dieta basal sorgo-soya, T2 como 1+7% DDGS, T3 como 1+14% de DDGS, T4 como 1+21% de DDGS. En el segundo experimento, se utilizaron 288 gallinas Bovans White de 35 semanas de edad, alojadas en jaulas durante 56 días de experimentación. Se usó un diseño completamente al azar de cuatro tratamientos con tres repeticiones de 12 gallinas cada una. Los tratamientos fueron: 1 dieta basal sorgo-soya, 2 como 1+3% DDGS, 3 como 1+6 % de DDGS, 4 como 1+9% de DDGS. Los resultados del Exp 1, indicaron que la adición del 7% de DDGS, no afectó el comportamiento productivo y de la canal (P>0.05. Los resultados en el Exp 2, mostraron que el empleo de 3, 6 y 9 % de DDGS no afectó el comportamiento productivo (P>0.05. Hubo un efecto benéfico (P<0.05 en la pigmentación de la yema del huevo, siendo mayor en los tratamientos con DDGS. Con los resultados obtenidos en este estudio, se puede concluir que la adición de DDGS en dietas sorgo-soya de hasta el 7 % en pollos de engorda y hasta 9 % en gallinas de postura, es una fuente alternativa de proteína y energía.

  9. Ensayo de disolución para las tabletas de Tilo ® elaboradas con extracto seco de Justicia pectoralis Jacq

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    Jorge Enrique Rodríguez Chanfrau

    2013-03-01

    Full Text Available Introducción: el ensayo de disolución es una técnica analítica de empleo común en un laboratorio farmacéutico. Un proceso tecnológico para la elaboración de tabletas fue desarrollado. El ingrediente farmacéutico activo usado fue Tilo ® extracto seco. Objetivo: el objetivo de este trabajo fue desarrollar y validar un ensayo de disolución para evaluar la estabilidad y la calidad de dicho producto. Método: se utilizaron muestras de un lote experimental, un lote placebo y lotes pilotos de tabletas de Tilo ® de 100 mg. Se evaluaron como medios de disolución agua destilada y solución de ácido clorhídrico 0,1 mol/L, realizándose perfiles de disolución a 50, 75 y 100 rpm, empleándose los dos tipos de aparatos establecidos en la literatura para este ensayo (cesta y paleta. El contenido de cumarina fue analizado por HPLC. El ensayo fue validado según la USP. Resultados: los resultados mostraron que el agua destilada fue un medio de disolución adecuado, alcanzándose porcientos de disolución de la droga por encima del 85 % a los 30 minutos, no existiendo diferencias significativas entre los tipos de aparatos recomendados por la USP. Mientras que, los perfiles de disolución a diferentes tiempos y velocidades de agitación mostraron una liberación gradual del principio activo en el tiempo, donde a medida que se incrementa la velocidad de agitación, se incrementa el porcentaje de disolución de la droga en el medio. La validación del ensayo demostró que el mismo era específico y preciso. Conclusiones: se estableció como ensayo de disolución las siguientes condiciones de trabajo: Aparato: paleta, 100 rpm; medio: agua destilada, 500 mL; tiempo: 60 minutos y Temperatura: 37 ± 0,5 ºC.

  10. Avaliação da biocompatibilidade de implantes mamários de silicone esterilizados por calor seco e pelo óxido de etileno Biocompatibility assessment of silicone gel breast implants sterilized by dry-heat and by ethylene oxide

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    Janice Campos de Azevedo

    2006-06-01

    Full Text Available Os implantes mamários de silicone têm sido empregados, tanto nas cirurgias de aumento de mama, quanto na reconstrução do tecido mamário. A segurança biológica deste tipo de implante deve ser garantida, pois, em função da esterilização estes materiais, podem sofrer alterações oriundas dos processos esterilizantes por comprometimento da estrutura química dos polímeros. O objetivo deste trabalho consistiu na avaliação da biocompatibilidade de implantes mamários preenchidos com gel de silicone, de superfície lisa e texturizada submetidos à esterilização por calor seco e óxido de etileno. Empregou-se, para tanto, método in vitro, avaliando a citotoxicidade pelo método de captura do vermelho neutro, utilizando a linhagem celular NCTC clone 929. Os resultados obtidos demonstraram não haver comprometimento da biocompatibilidade dos biomateriais submetidos aos dois processos (calor seco e óxido de etileno, assim como comprovaram a eficácia de ambos na esterilização dos implantes.Silicone breast implants have been widely used for mammary augmentation and reconstruction surgery. Biological safety of these implants can be altered by sterilization methods. This study consisted of the biocompatibility assessment of smooth and textured silicone gel breast implants sterilized by dry-heat and ethylene oxide through cell viability, employing neutral red uptake method. The NCTC clone 929 cell were employed and the results showed no cytotoxicity of implants after both sterilization processes.

  11. Hallazgos histopatológicos en pacientes con síndrome de ojo seco secundario a enfermedad autoinmune tratados con suero autógeno

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    Israel Luna Martínez

    2015-01-01

    Conclusiones: El tratamiento con suero autógeno ofrece una mejoría estadísticamente significativa en cuanto al aumento de células caliciformes conjuntivales y a la disminución del grado de metaplasia escamosa. En comparación, con el tratamiento con carboximetilcelulosa no se observaron cambios estadísticamente significativos después del tratamiento en ninguna de las variables.

  12. Estudio de mecanismos básicos de transferencia de calor con CFD fluent

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    Nieto Bautista, Javier

    2009-01-01

    Se propone realizar una simulación de manera que los datos proporcionados por el CFD (Computational Fluyd Dynamics) se evalúen en comparación a los datos experimentales, de manera que se adquieran los conocimientos y las técnicas necesarias para en un futuro poder obtener estos datos de manera virtual en una computadora o, por lo menos, comprobar la fiabilidad de los datos proporcionados por el fabricante. Para ello se estudian diferentes casos con distintas geometrías y condiciones de con...

  13. Factores ambientales asociados con la preferencia de hábitat de larvas de tricópteros en cuencas con bosque seco tropical (Tolima, Colombia

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    Jesús M. Vásquez-Ramos

    2014-04-01

    Full Text Available Los ríos de bosques secos tropicales están amenazados en todo el mundo, y en Suramérica son una de las prioridades en términos de conservación. En este estudio se determinó la influencia de variables ambientales (por ejemplo precipitación y la vegetación ribereña sobre las comunidades del orden Trichoptera en cuatro sustratos (roca, grava, arena y hojarasca en las cuencas Opia y Venadillo (Tolima, Colombia. En cada río, en dos segmentos de 100m (uno a ~550 y otro a ~250msnm, fueron evaluados los sustratos mencionados anteriormente. Se realizaron análisis físico-químicos, y se aplicó el índice QBR (calidad del bosque de ribera en ambos ríos. Se recolectaron 6 282 larvas, pertenecientes a 11 familias y 22 géneros, que representan el 73.30% y 43.13% de la fauna Trichoptera registrada en Colombia, respectivamente. Las familias más abundantes fueron Hydropsychidae (49.86% y Philopotamidae (25.44%. Los géneros Smicridea, Chimarra, Protoptila, Neotrichia y Leptonema fueron comunes en periodos de baja y alta precipitación. Las asociaciones de tricópteros no mostraron diferencias significativas a nivel de sustrato. Los principales factores que determinaron la composición, riqueza y abundancia de tricópteros fueron la estacionalidad y la vegetación de ribera. Sin embargo, las localidades situadas a mayor altitud y no urbanizadas, ofrecen mayor variedad de sustratos y mayor riqueza de géneros. Nuestros resultados indican que a futuro las larvas de Trichoptera constituyen un elemento biótico relevante en los ecosistemas dulceacuícolas, debido a que son sensibles a disturbios ambientales. Por ende, sugerimos el uso de los tricópteros para biomonitoreo en ríos tropicales. La implementación de estos estudios es urgente, teniendo en cuenta que la degradación de los ecosistemas dulceacuícolas tiende a ser intensa y persistente.

  14. SECO containment data report

    Energy Technology Data Exchange (ETDEWEB)

    Stubbs, T.; Heinle, R.

    1997-06-01

    This containment data report for the SECO event provides a description of the event, including the site, emplacement, and instrumentation. Stemming performance is reported, including radiation, pressure, collapse phenomena, and motion. Surface array measurements are provided.

  15. Research and technological development on heat pumps in Mexico operating with geothermal energy; Investigacion y desarrollo tecnologico sobre bombas de calor en Mexico operando con energia geotermica

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Gutierrez, Alfonso; Barragan Reyes, Rosa Maria; Arellano Gomez, Victor Manuel [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2008-07-01

    The Instituto de Investigaciones Electricas (IIE) and the Comision Federal de Electricidad (CFE) carried out in the past an extensive work of research and development (R&D) on heat pumps (HP). The systems tried on include heat pumps by mechanical compression, thermal absorption and thermal transformers. This paper briefly describes the main aspects of R&D on heat pumps and presents a more detailed description of three of the main studies: a) a Heat Pump (HP) by mechanical compression water-water type, designed for brine purification, operating with low pressure geothermal steam at the geothermal field Los Azufres, Michoacan, Mexico; b) a HP by absorption for cooling and refrigeration, operating with ammoniac/water and low enthalpy geothermal energy, which was tested in the geothermal fields of Los Azufres, Michoacan and Cerro Prieto, Baja California, and c) a thermal transformer by absorption, named Heat Pump by Absorption Type 2, which was tested to evaluate the behavior of diverse ternary solutions as working fluids. To date, there are plans to install and test a geothermal heat pump (connected to the subsoil), in Cerro Prieto, Mexicali, Baja California, Mexico. [Spanish] El Instituto de Investigaciones Electricas (IIE) y la Comision Federal de Electricidad (CFE) realizaron un trabajo extenso de investigacion y desarrollo (I&D) sobre bombas de calor (BC) en el pasado. Los sistemas que se probaron incluyen bombas de calor por compresion mecanica, absorcion y transformadores termicos. Este trabajo describe brevemente los principales aspectos de I&D sobre bombas de calor y se da una descripcion mas detallada de tres de los principales estudios: a) una Bomba de Calor (BC) por compresion mecanica tipo agua-agua, disenada para purificacion de salmueras, operando con vapor geotermico de baja presion en el campo geotermico de Los Azufres, Michoacan; b) una BC por absorcion para enfriamiento y refrigeracion, operando con amoniaco/agua y energia geotermica de baja entalpia

  16. REDUCCIÓN DE LA CANTIDAD DE Vibrio mimicus CON CALOR O ÁCIDO ACÉTICO EN HUEVO DE TORTUGA (Lepidochelys olivacea)

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    M\\u00F3nica Pereira-Zamora; Eric Wong-Gonz\\u00E1lez

    2010-01-01

    Este estudio se realizó en el Ce ntro Na cional de Cie ncia y Tecnología de Alimentos en el año 2000, con el fin de determinar la reducción de Vibrio mimicus en huevo de tortuga lora utilizando calor o ácido acético. Para ellos se determinó el tiempo de coagulación a diferentes temperaturas o niveles de pH con el fin de seleccionar los que podían utilizarse para la reducción del patógeno sin afectar las cualidades sensoriales del huevo crudo. Los huevos inoculados con Vibrio mimicus con carga...

  17. Manejo en seco de rosa de corte (Rosa hybrida L.) y su relación con la obstrucción vascular

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    Elizondo Gómez, Guadalupe

    2012-01-01

    El objetivo de este trabajo fue conocer el efecto de diversos compuestos en la inhibición de la obstrucción vascular en tallos de rosa (Rosa hybrida, L.) ‘Grand Gala’ almacenados en seco, a través de variables como: vida de florero, apertura del botón floral, peso fresco, transpiración, actividad enzimática y contenido de fenoles totales. Para ello, se realizaron dos experimentos. En el primero se utilizaron soluciones de ácido aminoxiacético (AOA) (1 y 2 mM) y putrescina (25 mg L-1). En el s...

  18. Solución numérica de procesos de transferencia de calor en aleaciones con condiciones de contorno no lineales

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    Alhama, F.

    2005-12-01

    Full Text Available Thermal properties of a great number of alloys, especially specific heat, show a sharply temperature dependence both during the phase change and the allotropic transformations. This fact, in conjunction with the existence of convection or radiation boundary conditions, or both simultaneously, increase the complexity of the transient heat transfer problem because of the inherent no linearity. The numerical model proposed for the solution of this problem is able to assume the above hypothesis as well as the temperature dependencies of the thermal conductivity. Applications to alloys are presented.

    Las propiedades térmicas de numerosas aleaciones, especialmente la capacidad calorífica, acusan una marcada dependencia con la temperatura tanto en los cambios de fase como en las transformaciones alotrópicas. Este hecho, junto con la aplicación de condiciones de contorno de convección, radiación o ambas, simultáneamente, aumentan la complejidad del problema de transferencia de calor en los procesos transitorios debido a la no linealidad inherente. El modelo numérico propuesto para la solución de este problema es capaz de asumir las hipótesis anteriores así como las posibles dependencias de la conductividad térmica con la temperatura. Se presentan aplicaciones a procesos térmicos en aleaciones.

  19. FLUJO INTERNO MIXTO CON DIFUSIÓN DOBLE DE CALOR Y MASA EN UNA CAVIDAD RECTANGULAR MIXED INTERNAL FLOW WITH DOUBLE DIFFUSION OF HEAT AND MASS

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    Carlos H Salinas Lira

    2008-09-01

    Full Text Available El presente trabajo muestra resultados de transporte de calor y masa (Doble al interior de una cavidad rectangular ocasionado por un flujo convectivo forzado y natural (Mixto. El modelo matemático consta de las ecuaciones de Navier-Stokes para describir el flujo laminar de un fluido incompresible. Además es modelado el transporte de calor y masa a través de dos ecuaciones diferenciales lineales de segunda orden, incorporando en forma lineal los efectos de los gradientes de concentración y de temperaturas. El modelo matemático es resuelto numéricamente a través del Método de Volúmenes Finitos descrito en coordenadas curvilíneas y variables colocalizadas, representando los términos difusivos a través de diferencia central y usando un esquema potencial para los términos convectivos. Se muestran resultados originales de patrones de flujo: Isotermas, isoconcentraciones y números de Nusselt y de Sherwood en regiones características para el problema de flujo interno mixto con difusión de calor y masa.The present work shows the relationship of the transport of heat and mass (double in a rectangular cavity caused by a forced and natural convection. The mathematical model consists of the Navier-Stokes equations to describe the incompressible laminar flow. The transport of heat and mass are modelled through two second order no-linear differential equations, incorporating in linear way the effects of gradients of concentrations and temperature. The mathematical problems is solved numerically through the Finite Volumes Method, in curvilinear coordinated and co-located variables, representing the diffusion through central difference and using a potential schemes for the convection terms. Original results of flow models are shown: Isotherms, isoconcentrations and numbers of Nusselt and Sherwood in characteristic regions for the mixed internal flow problem with heat and mass are shown.

  20. Oclusión canalicular con tapones de silicona de Herrick en el tratamiento del ojo seco Canicular occlusion with Herrick silicone plugs in the treatment of dry eye

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    Jaime Alemañy González

    2002-06-01

    Full Text Available Para evaluar la desaparición de síntomas y signos en el síndrome de ojo seco por deficiencia del componente acuoso de la película lagrimal, se estudiaron 15 pacientes que llevaban tratamiento con lágrimas artificiales, a pesar de lo cual presentaban síntomas por sequedad ocular. Se realizó oclusión canalicular de prueba con tapones de colágeno y luego definitiva con los de silicona de Herrick en el canalículo inferior. Se evaluaron por consulta hasta un año después del proceder. Se encontró que el 52 % de los casos tuvieron desaparición de los síntomas, el 40 % necesitaron añadir colirio de lágrimas artificiales ocasionalmente y el 8 % de los casos necesitaron oclusión del canalículo superior. Este tratamiento es un método sencillo y efectivo, que proporciona alivio a largo plazo a los pacientes con síndrome de ojo seco, mejorando su calidad de vida.To evaluate the disappearance of symptoms and signs in the dry eye syndrome due to deficiency of the aqueous component of the lacrimal film, 15 patients that were under treatment with artificial tears, although they still had symptoms resulting from ocular dryness, were studied. Canicular occlusion with collagen plugs was performed first as a test and then definitive occlusion with Herrick silicone plugs in the inferior canaliculus. These patients were evaluated at the physician’s office a year after the procedure. It was found that the symptoms dissappeared in 52 % of the cases, that 40 % needed to add occasionally collyrium of artificial tears and that 8 % of them required occlusion of the superior canaliculus. This treatment is a simple and effective method that provides long-term release to patients with dry eye syndrome and improves their quality of life.

  1. Calore e termodinamica

    CERN Document Server

    Zemansky, Mark W

    1970-01-01

    Temperatura ; sistemi termodinamici semplici ; lavoro ; il calore e il primo principio ; gas ideali ; teoria cinetica dei gas ideali ; il secondo principio della termodinamica ; reversibilità e temperatura Kelvin ; entropia ; meccanica statistica sostanze pure ; transizioni di fase, elio liquido ed elio solido ; sistemi particolari ; paramagnetismo, fisica delle basse temperature, temperature negative e terzo principio ; superfluidità e superconduttività ; equilibrio chimico ; reazioni con gas ideali ; sistemi eterogenei.

  2. Thermal and friction drop characteristic of heat exchangers with elliptical tubes and smooth fins//Caracterización térmica e hidráulica de intercambiadores de calor con tubos elípticos y aletas lisas

    Directory of Open Access Journals (Sweden)

    Rubén Borrajo-Pérez

    2012-09-01

    Full Text Available Pressure drop and heat transfer are the most important parameters in compact heat exchanger. There is a lack of information in the literature about heat exchanger with elliptical tube. The objective of this work was the experimental characterization of compact heat exchangers models using elliptical tube with eccentricity of 0,5 and smooth fins. The Reynolds numbers and the spacing were varied and always inside laminar regime. The experiments were conducted in an open wind tunnel using sublimation of naphthalene and the heat and mass transfer analogy. As results, the average and local Nusselt number and friction factor for 36 models were obtained. Correlations for Colburn and friction factors were presented. This correlations were obtained for 200calor son importantes parámetros en intercambiadores de calor. Existe falta de información cuando de intercambiadores de calor y tubos elípticos se trata. El objetivo del trabajo fue caracterizar experimentalmente modelos de intercambiadores de calor con tubos elípticos yaletas lisas. El numero de Reynolds y los espaciamientos fueron variados, dentro del régimen laminar. Los experimentos fueron desarrollados en un túnel de viento de circuito abierto usando la sublimación de naftaleno y la analogía calor y masa. Los números de Nusselt medio, locales y el factor de fricción fueronobtenidos en forma de correlaciones de Factores de Fricción y Colburn. Las correlaciones, validas para 200

  3. CARACTERIZACIÓN MOLECULAR Y GERMINACIÓN DE SEMILLAS DE MAÍCES CRIOLLOS AZULES CON ENVEJECIMIENTO ACELERADO

    Directory of Open Access Journals (Sweden)

    Dagoberto Dur\\u00E1n-Hern\\u00E1ndez

    2011-01-01

    Full Text Available El objetivo del presente estudio fue determinar el efecto del envejecimie nto acelerado en semillas de varie dades criollas de maíz azul. En los laboratorios de la Universidad Nacional Autónoma de México y del Instituto Politécnico Nacional, semillas de cuatro varie dades criollas de maíz azul (Cuijingo, Cocotitlán, Puebla y Oaxaca, se sometie ron a dos tip os de envejecimie nto acelerado: calor húmedo (41°C, 72 horas y 100% h. r. y calor seco (60°C, 48 horas. Se evaluaron: protrusión radicular de 0 a 72 horas de imbibición y, a los sie te días de incubación a 25°C, plántulas normales, anormales y semillas muertas. Se obtuvo la caracterización molecular de los tratamie ntos mediante la RA PD y se construyeron los dendogramas respectivos. En plántulas normales provenie ntes de semillas sin envejecimie nto acelerado, las varie dades Oaxaca y Puebla fueron significativamente superiores. El peso seco en las plántulas disminuyó con el deterioro, sie ndo exigua con calor seco. La presencia de plántulas anormales se incrementó con ambos tip os de deterioro en el orden: Oaxaca, Puebla, Cocotitlán y Cuijingo. La diferenciación de los perfiles de bandeo entre semillas testigo y deterioradas ocurrió con la secuencia: Oaxaca (31,6%, Cocotitlán (25,8%, Puebla (19,6% y Cuijingo (18,6%. Estos valores de similitud, a los cuales se ramificaron los perfiles genómicos, se asociaron de manera inversa con el nivel de vigor de las semillas, y directamente con la presencia de anormalidades en las plántulas obtenidas.

  4. Cronología de la regeneración del bosque tropical seco en Santa Rosa, Guanacaste, Costa Rica: II. La vegetación en relación con el suelo

    Directory of Open Access Journals (Sweden)

    Jorge A Leiva

    2009-09-01

    Full Text Available Se estudió la sucesión del bosque tropical seco (BTS de Santa Rosa, Guanacaste, Costa Rica, en cinco sitios boscosos secundarios y tres bosques maduros. Se analizó el efecto de la clase de suelo sobre la estructura del bosque y la diversidad de especies arbóreas. Los ocho sitios sucesionales estaban localizados a lo largo de una cronosecuencia de regeneración (10, 15, 20, 40, 60 and >100 años en la que se identificaron 17 pedones y seis órdenes de suelos con moderada a alta fertilidad, clasificados como Entisoles y Vertisoles, aunque los Mollisoles, Alfisoles, Inceptisoles y Ultisoles estuvieron presentes también. Se establecieron 130 parcelas de 10 por 50 m (0.05 ha, 20 en cada bosque secundario y 10 en cada bosque antiguo (6.5 ha en total, de acuerdo con la topografía. Se midió el diámetro a la altura de pecho (dap de todos los individuos presentes en cada parcela, la altura dominante y el área basal (m2ha-1, usando dos poblaciones: latizales (dap ≥ 1 y Chronology of tropical dry forest regeneration in Santa Rosa, Guanacaste, Costa Rica. II. Vegetation in relation to the soil. Tropical dry forest (TDF succession was monitored in Santa Rosa, Costa Rica. We analyzed the effect of soil type on forest structure and diversity. Eight seasonally-dry TDF sites located along a successional chrono-sequence (10, 15, 20, 40, 60 and >100 years were examined in relation to 17 soil pedons and six soil orders. Soils had moderate to high fertility and were classified as Entisols and Vertisols, although Mollisols, Alfisols, Inceptisols and Ultisols were also present. One-hundred and thirty 500 m2 plots were established, 20 plots in secondary and 10 plots in mature TDFsites. Diameter at breast height (dbh and total tree height were measured for saplings (dbh ≥1 and <5 cm, shrubs and trees (dbh ≥5 cm. With the exception of two sites (40 and 60 years, soil type did not have significant effects on forest structure. However, tree diversity measured

  5. Transferencia de calor incrementada en espacios anulares con elementos helicoidales insertados//Review of augmentation techniques for heat transfer coefficient in annular spaces using helical elements

    Directory of Open Access Journals (Sweden)

    Josué Imbert‐González

    2014-08-01

    Full Text Available La transferencia de calor incrementada por métodos pasivos se emplea en diversosintercambiadores de calor de alta efectividad. El objetivo del trabajo presentado fue la evaluación del estado de las investigaciones en el campo de la transferencia de calor mejorada en espacios anulares, a partir del empleo de elementos turbulizadores helicoidales como técnicas pasivas. La revisión se centró en el empleo de láminas helicoidales y espirales, la obtención de ecuaciones de correlación del coeficiente de transferencia de calor incrementado, el coeficiente de fricción y la evaluación que se realiza de este proceso por parte de diferentes autores. El análisis crítico permitió realizar valoraciones integradas y recomendar sobre los aspectos que podrían ser analizados en el futuro en esta temática.Palabras claves: transferencia de calor incrementada, láminas helicoidales, espirales, espacios anulares, métodos pasivos._______________________________________________________________________________AbstractThe transfer enhancement by passive methods is used in several heat exchanger of high effectiveness. The objective of the presented work was the evaluation of the state of the investigations in heat transfer enhancement in annular spaces, from the employment of elements helical. The revision was centered in the employment of twisted tape and wire coil in spiral, the equations of correlation obtained of the coefficient of transfer of increased heat, the coefficient of friction and the evaluation that was carried out of this process on the part of different authors. From the critical analysis of the published results, the authors recommend on the topics that can be analyzed in the future in this area.Key words: heat transfer enhancement, twisted tape, helical springs, annular spaces, passive methods.

  6. Dique seco de carena

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    Editorial, Equipo

    1963-10-01

    unos 48 m de anchura, a cada lado del futuro dique. En una segunda fase se construirá un muelle de atraque. Las modernas instalaciones con que cuenta el nuevo dique cubren todas las necesidades principales que este tipo de reparaciones requiere, lo que hará del conjunto un complejo operacional económico y eficiente. Se estudiaron varias soluciones y lugares de emplazamiento, ya que el fondo de la bahía presenta varias capas de fangos y arenas de distinta granulometría que hacían prever posibles dificultades para cimentar. La capa superior admitida como base aceptable para la sustentación de la obra, está constituida por un banco sedimentario de detritus glaciares. El lugar elegido para la ubicación de la obra presenta la ventaja de ser la parte de afloramiento más superficial de dicho banco. El proyecto ofrecía dos alternativas: una, en la que se admite suficiente masa de hormigón para asegurar la estabilidad por gravedad, y otra, en la que la subpresión aliviaría la carga, pero previendo un desagüe en el que la altura máxima del nivel hidrostático quedara asegurada. Los dragados y el hormigonado se han llevado a cabo con medios auxiliares potentes y modernos, y los rellenos se han efectuado siguiendo procedimientos hidráulicos.

  7. Ensayo de disolución para las tabletas de Tilo ® elaboradas con extracto seco de Justicia pectoralis Jacq Dissolution Assay for Tilo ® tablets prepared with dry extract of Justicia pectoralis Jacq

    OpenAIRE

    Jorge Enrique Rodríguez Chanfrau; Jose Manuel Gil Apan

    2013-01-01

    Introducción: el ensayo de disolución es una técnica analítica de empleo común en un laboratorio farmacéutico. Un proceso tecnológico para la elaboración de tabletas fue desarrollado. El ingrediente farmacéutico activo usado fue Tilo ® extracto seco. Objetivo: el objetivo de este trabajo fue desarrollar y validar un ensayo de disolución para evaluar la estabilidad y la calidad de dicho producto. Método: se utilizaron muestras de un lote experimental, un lote placebo y lotes pilotos de tableta...

  8. Plan de negocio para Tamarindo Seco S.A.S

    OpenAIRE

    Salazar Briceño, Julián Danilo; Vargas Gallego, Daniel Felipe; Lotta Gamba, Sebastián Rodrigo

    2017-01-01

    El planteamiento inicial del plan de negocios para Tamarindo Seco tiene como objetivo encontrar oportunidades de negocio con los productos actuales para involucrase y aportar al sector de consumo masivo en lo que se refiere a la alimentación saludable, con el único fin de cumplir un propósito superior, promover una cultura medio ambiental sostenible a través de la modificación en el manejo que se le da a los desperdicios que genera el consumo masivo de alimentos en Colombia y la región. Tenie...

  9. Simulación numérica de flujo de aire y transferencia de calor en un enfriador vertical con puerta panorámica

    OpenAIRE

    Narváez Buestán, Freddy Eduardo

    2017-01-01

    En este proyecto de investigación se analizan los flujos de aire y transferencia de calor en el interior de un Enfriador vertical. El aire sale por el cobertor y se visualiza mediante el software Ansys Fluent como el diseño influye en la distribución de flujo. Se propone una mejora en el diseño del Cobertor optimizando la distribución del flujo. In this research project the air flows and heat transfer inside a Vertical Cooler are analyzed. The air comes out through the cover panel freez...

  10. ARROYO SECO ROADLESS AREA, CALIFORNIA.

    Science.gov (United States)

    Powell, Robert E.; Gabby, Peter N.

    1984-01-01

    Situated in the southwestern San Gabriel Mountains in Los Angeles County, California, the Arroyo Seco Roadless Area encompasses about 8 sq mi within the Angeles National Forest. On the basis of geologic mapping, a geochemical stream-sediment survey, and a survey of mines, quarries, and prospects, the area has a probable resource potential for small gold occurrences in the southern part of the area. Sand, gravel, and stone suitable for construction materials are found in the roadless area. Because of their regional association with gold mineralization, the thin and poorly exposed mafic dikes in the Echo Granite, the Mount Lowe Granodiorite, and the Precambrian gneiss in and around the roadless area offer the most promising avenue for additional study of the resource potential of the area.

  11. Periodo seco corto en ganado de leche (Short dry period in dairy cattle)

    OpenAIRE

    Jorge A Elizondo Salazar

    2007-01-01

    Resumen Un periodo seco de 60 días ha sido suficiente para permitir que vacas con un considerado por muchos años como una manejo adecuado, buena alimentación y norma de manejo entre lactancias sucesivas condición corporal produzcan, en la siguiente para asegurar una producción óptima de lactancia, cantidades de leche similares a las leche. A pesar de ello, su aplicabilidad ha sido obtenidas con vacas que han tenido un cuestionada en los últimos años, debido a que periodo seco de 60 días. Di...

  12. Estudio experimental de la conducción del calor en el maquinado de materiales endurecidos con altas velocidades de corte. // Experimental study of heat conduction in mechanization with high cutting speeds of hardened materials.

    Directory of Open Access Journals (Sweden)

    L. Cardoso Brandão

    2006-01-01

    Full Text Available El trabajo trata del estudio teórico-experimental de la conducción del calor en los materiales endurecidos, usados para laproducción de moldes y matrices, al maquinarlos con altas-velocidades del corte. Los materiales utilizados son los acerosAISI P20 y AISI D2. Los ensayos se realizaron con fresas de punta esférica (Ball Nose con revestimiento (TiAlN y lasprobetas para los ensayos tienen la forma de una ¼ parte de un tubo de 28 mm de diámetro con una longitud de 100 mm.Las pruebas realizadas demuestran la variación de la temperatura en función de los diferentes sistemas de refrigeración. Seutilizo aire comprimido y aire comprimido frío, comparándose las temperaturas de las probetas con el sistema sinrefrigeración de ningún tipo. Fueron también evaluadas las deformaciones sufridas por la superficie maquinada, debido alas variaciones de temperatura teniendo en cuenta la influencia de los sistemas de refrigeración empleados.Palabras claves: Temperatura; conducción del calor; alta velocidad de corte, moldes y matrices._________________________________________________________________________Abstract.This paper deals with the theoretical-experimental study of heat conduction in hardened materials for the production ofmolds and dies using high speed cutting. The employed materials were the AISI P20 and AISI D2 steels, being the testscarried out with (TiAlN coated ball nose in a work piece with the shape of a 1/4 tube with 28 mm diameter and 100 mmlength. This investigation demonstrates the variation of temperature as a function of different cooling systems, that is,compressed air and compressed cold air. Possible geometric deformation of the machined surfaces due to these variationsin temperature for distinct cooling systems was also evaluated.Keywords: Temperature, heat exchange; high cutting speed, dies.

  13. Estudio sobre la susceptibilidad a periodo seco en flores de corte (Rosa hybrida).

    OpenAIRE

    Mosqueda Lázcares, Gabriela

    2011-01-01

    Se evaluó la respuesta de tallos de rosa (Rosa hybrida) de los cultivares Freedom, Red alfa, Red vicer, Opera, Pecubo, Vendela, Royalty, Grand gala y Sena al almacenamiento en seco considerando la influencia de la época de corte y dos períodos de almacenamiento con el objetivo de proponer a los productores de flores del estado de México un manejo alternativo (seco) al que de forma tradicional emplean (húmedo). Pese a que se observaron diferencias significativas entre cultivares, en general to...

  14. UNA BREVE DESCRIPCIÓN DE LA VEGETACIÓN, CON ESPECIAL ÉNFASIS EN LAS PIONERAS INTERMEDIAS DE LOS BOSQUES SECOS DE LA JAGUA, EN LA CUENCA ALTA DEL RÍO MAGDALENA EN EL HUILA

    National Research Council Canada - National Science Library

    William Vargas

    2015-01-01

    ... interés en especies pioneras intermedias que puedan apoyar procesos de restauración ecológica y conservación de la biodiversidad, estos datos se compararon con los obtenidos en campo durante...

  15. PARTICIÓN DE MICROHÁBITATS ENTRE ESPECIES DE BUFONIDAE Y LEIUPERIDAE (AMPHIBIA: ANURA EN ÁREAS CON BOSQUE SECO TROPICAL DE LA REGIÓN CARIBE-COLOMBIA Microhábitat Partitioning Between Leiuperidae and Bufonidae Species (Amphibia: Anura in Tropical Dry Forest Areas in Colombian Caribbean

    Directory of Open Access Journals (Sweden)

    ARGELINA BLANCO TORRES

    Full Text Available RESUMEN Se analizó la partición de microhábitats de cinco especies de anuros pertenecientes a las familias Bufonidae (Rhinella marina, R. granulosa, y Leiuperidae (Engystomops pustulosus, Pleurodema brachyops y Pseudopaludicola pusilla en seis localidades del Caribe colombiano con fragmentos de bosque seco tropical y diferentes usos de suelo. Se identificaron 29 microhábitats. Los más usados fueron charco de agua permanente de potreros con árboles (CPPA y potreros inundables sin árboles (PISA. La especie que mayor cantidad de microhábitats utilizó, fue E. pustulosus. No hubo especialistas en el uso de estos ambientes. Se presentaron diferencias en el uso de este recurso a escalas regional y local. La dinámica de uso de los microhábitats estuvo influenciada por las variaciones climáticas del bosque seco tropical. Existió partición de microhábitats como mecanismo de coexistencia en estas especies para época seca y no ocurre en época de lluvias.ABSTRACT We analyzed partitioning of microhábitats by five species of frogs in the families Bufonidae (Rhinella marina, R. granulosa, and Leiuperidae (Engystomops pustulosus, Pleurodema brachyops and Pseudopaludicola pusilla in six different localities of the Colombian Caribean with tropical dry forest fragments and different land uses. We identified 29 types of microhábitats; permanent ponds in pastures with trees (CPPA and flooded pastures without trees (PISA were the most important environmental used. Engystomops pustulosus used the must microhábitats, and none are used by specialist species. Thus, differences in the use of resource on regional and local scales appeared. Dynamics of microhábitat uses was influenced by the climatic variations of the tropical dry forest. Microhábitats distribution as a mechanism of coexistence in these species is implemented for dry season but in rainfall season this mechanism not exists.

  16. Síndrome de ojo seco Dry eye syndrome

    Directory of Open Access Journals (Sweden)

    Rafael Balbona Brito

    2005-06-01

    Full Text Available Se realizó una revisión bibliográfica sobre el síndrome de ojo seco, que abarcó su clasificación, diagnóstico y tratamiento. Se tuvo en cuenta que constituye una entidad frecuente en la Oftalmología; se presenta con la finalidad de mostrar el síndrome de manera actualizada y con el objetivo de facilitar su manejoA bibliographic review of the dry eye syndrome that included its classification, diagnosis and treatment is made. Taking into account that it is a frequent entity in Ophthalmology, it is presented in order to provide an updating of the syndrome and to facilitate its management

  17. Ensayo de disolución para las tabletas de Tilo ® elaboradas con extracto seco de Justicia pectoralis Jacq Dissolution Assay for Tilo ® tablets prepared with dry extract of Justicia pectoralis Jacq

    Directory of Open Access Journals (Sweden)

    Jorge Enrique Rodríguez Chanfrau

    2013-03-01

    Full Text Available Introducción: el ensayo de disolución es una técnica analítica de empleo común en un laboratorio farmacéutico. Un proceso tecnológico para la elaboración de tabletas fue desarrollado. El ingrediente farmacéutico activo usado fue Tilo ® extracto seco. Objetivo: el objetivo de este trabajo fue desarrollar y validar un ensayo de disolución para evaluar la estabilidad y la calidad de dicho producto. Método: se utilizaron muestras de un lote experimental, un lote placebo y lotes pilotos de tabletas de Tilo ® de 100 mg. Se evaluaron como medios de disolución agua destilada y solución de ácido clorhídrico 0,1 mol/L, realizándose perfiles de disolución a 50, 75 y 100 rpm, empleándose los dos tipos de aparatos establecidos en la literatura para este ensayo (cesta y paleta. El contenido de cumarina fue analizado por HPLC. El ensayo fue validado según la USP. Resultados: los resultados mostraron que el agua destilada fue un medio de disolución adecuado, alcanzándose porcientos de disolución de la droga por encima del 85 % a los 30 minutos, no existiendo diferencias significativas entre los tipos de aparatos recomendados por la USP. Mientras que, los perfiles de disolución a diferentes tiempos y velocidades de agitación mostraron una liberación gradual del principio activo en el tiempo, donde a medida que se incrementa la velocidad de agitación, se incrementa el porcentaje de disolución de la droga en el medio. La validación del ensayo demostró que el mismo era específico y preciso. Conclusiones: se estableció como ensayo de disolución las siguientes condiciones de trabajo: Aparato: paleta, 100 rpm; medio: agua destilada, 500 mL; tiempo: 60 minutos y Temperatura: 37 ± 0,5 ºC.Introduction: dissolution testing is one of the most common analytical techniques performed in a pharmaceutical analytical laboratory. A technological process for the production of tablets was developed. The active pharmaceutical ingredient used was

  18. Montaje y ensayo de la producción de hielo líquido en un intercambiador de calor de placas con superficie rascada de forma rotativa

    OpenAIRE

    Durán Plazas, Juan Manuel

    2013-01-01

    El hielo líquido se puede definir como una mezcla de cristales de hielo y una solución acuosa. Esta solución se compone de agua con uno o más solutos que provoquen la depresión del punto de congelación, para permitir el descenso de temperatura a rangos negativos y por consiguiente la coexistencia de una fase sólida y otra líquida. Debido a estas características, el fluido se puede transportar, bombear, transportar por tuberías y almacenar en tanques. Sin embargo, para generar hielo líquido no...

  19. Mecanismos efectores de las células fagocíticas estimuladas in vitro con S. Pyogenes vivo e inactivado por calor

    Directory of Open Access Journals (Sweden)

    Agustín C. Möhlinger

    2013-01-01

    Full Text Available Introducción: Los estreptococos del Grupo A son patógenos frecuentes en los seres humanos, responsables de diversas infecciones. Diferentes estudios  han demostrado mecanismos involucrados en las defensas del huésped frente a la infección por S. pyogenes. S. pyogenes desencadena una respuesta inmune importante con la consiguiente participación de diversos tipos celulares, como polimorfonucleares neutrófilos, macrófagos y células dendríticas, así como las subpoblaciones TH1 y Th2. El presente estudio pretende describir la respuesta de Polimorfonucleares (PMNs y Mononucleares (MNs de sujetos normales frente al S. pyogenes vivo (Spv e inactivado (Spi. Materiales y Métodos: Se separaron los PMNs y MNs de sangre periférica de 48 sujetos donantes sanos. Se incubaron en tubos separados las suspensiones de PMN y MNs en medio RPMI 1640 con 5l las suspensiones de S. pyogenes vivo (Spyv e inactivado (Spyi. Se evaluaron nitritos por el Método de Griess y TNFα por ELISA ( R& D Systems. En PMNs y MNs se determinó el Estallido Respiratorio (ER por Citometría de Flujo. Resultados: Estallido Respiratorio. R(x± E.E.: PMNs est. c/Spv: 2,50±0,478; PMNs est. c/Spi: 1,921±0,275; PMNs Basal: 1,282±0,105. P=0,0483. MNs est. c/Spv: 2,56±0,51; MNs est. c/Spi: 1,92±0,27; MNs Basal: 1,21±0,10. Spv vs Spi P>0,05 ns; Spv vs basal P0,05ns. Niveles Nitritos(x± E.E. MNs est c/ Spv, Spi y Basal: 40,75±5,94; 57,85±8,79; 13,28±1,13. MNs Basal vs MNs Spv P0,05 NS. Niveles de TNFα(x± E.E.: PMNs est c/ Spv, Spi y Basal: 223,54±21,49; 202,78±37,37; 100,82±3,23. PMNs Spv vs Spi P>0,05ns; PMNs Spv vs Basal P0,05 NS; Spv vs Basal P<0,01; Spi vs Basal P<0,05. Discusión: Se determinó que el S. pyogenes tanto vivo como inactivado tiene capacidad para estimular a las células fagocíticas, activando su capacidad oxidativa através del Estallido Respiratorio, la producción de nitritos y la de TNF alfa en sobrenadante de cultivo Celular incrementado su

  20. MECANISMOS EFECTORES DE LAS CÉLULAS FAGOCÍTICAS ESTIMULADAS IN VITRO CON S. PYOGENES VIVO E INACTIVADO POR CALOR

    Directory of Open Access Journals (Sweden)

    Agustín C. Möhlinger

    2012-01-01

    Full Text Available Objetivos: Los estreptococos del Grupo A son patógenos frecuentes en los seres humanos, responsables de diversas infecciones. Diferentes estudios han demostrado mecanismos involucrados en las defensas del huésped frente a la infección por S. pyogenes. S. pyogenes desencadena una respuesta inmune importante con la consiguiente participación de diversos tipos celulares, como polimorfonucleares neutrófilos, macrófagos y células dendríticas, así como las subpoblaciones TH1 y Th2. El objeto del presente estudio fue examinar la respuesta de Polimorfonucleares (PMNs y Mononucleares (MNs de sujetos normales frente al S. pyogenes vivo (Spv e inactivado(Spi. Métodos: Se separaron los PMNs y MNs de sangre periférica de 48 sujetos donantes sanos. Se incubaron en tubos separados las suspensiones de PMN y MNs en en medio RPMI 1640 con 5l de las suspensiones de S. pyogenes vivo (Spyv e inactivado (Spyi . En el sobrenadante de cultivo de MN y PMN, se evaluaron nitritos (Método de Griess y TNFα [ELISA ;R& D Systems]. En dichas células se determinó el Estallido Respiratorio (ER por Citometría de Flujo. Resultados: Estallido Respiratorio. R(X± E.E.: PMNs est. c/Spv: 2,50±0,478; PMNs est. c/Spi: 1,921±0,275; PMNs Basal: 1,282±0,105. P=0,0483. MNs est. c/Spv: 2,56±0,51; MNs est. c/Spi: 1,92±0,27; MNs Basal: 1,21±0,10. Spv vs Spi P>0,05 ns; Spv vs basal P0,05ns. Niveles Nitritos(x± E.E. MNs est c/ Spv, Spi y Basal: 40,75±5,94; 57,85±8,79; 13,28±1,13. MNs Basal vs MNs Spv P0,05 NS. Niveles de TNFα(x± E.E.: PMNs est c/ Spv, Spi y Basal: 223,54±21,49; 202,78±37,37; 100,82±3,23. PMNs Spv vs Spi P>0,05ns; PMNs Spv vs Basal P0,05 NS; Spv vs Basal P<0,01; Spi vs Basal P<0,05. Conclusiones: Se determinó que el S. pyogenes tanto vivo como inactivado tiene capacidad para estimular a las células fagocíticas, activando su capacidad oxidativa através del Estallido Respiratorio, la producción de nitritos y la de TNF alfa en sobrenadante de

  1. Dique seco de carena. Génova

    Directory of Open Access Journals (Sweden)

    Gai, Luigi

    1965-02-01

    Full Text Available After elaborate planning, the building, towing and sinking of the ship repairing dry dock at Genoa has now been completed. The dock is 260x52x21.5 m in size. Its structure is cellular and it is made of reinforced and prestressed concrete. A special feature of this dock is that it rests on a flexible bed of sand, dredged from the sea bed. To prepare this, the following operations were carried out: mud was first dredged away, the stony outcrops were levelled off, the spaces in between the rocks were filled with concrete, then the layer of sand was placed, and finally a surface of larger aggregate was prepared on top. The method of attaching the dock to the sea bed to ensure its stability is also noteworthy. After much thought, it was decided that once the dock was sunk at its final emplacement, if its cellular compartments were filled with sand ballast, its own weight would ensure its permanent stability in the face of rough seas. The maneuvers for floating the dock, and sinking it, were also complex, since it was essential to take carefully into account the state of the weather. Any storm might have severely damaged the dock's cellular structure. The prefabrication of the caissons, the jointing of them into a large structure, the construction of enclosing walls, the provision of galleries, companionways, and housing facilities inside the dock, and the towing, sinking and ballasting of this large and heavy structure, constitute a series of building and navigational operations of great complexity, which have tested the ability of the firm Fincosit, who specialise in hydraulic projects.Después de profundos estudios se ha terminado recientemente la construcción, remolque y hundimiento del dique seco de carena del puerto de Génova, cuyas dimensiones son: 260x52x21,5 metros. Es de estructura celular, y de hormigón armado y pretensado. La particularidad de la obra estriba en el apoyo de la plataforma sobre un lecho flexible de arena dragada del mar

  2. Primeros resultados del análisis de ADN mitocondrial del sitio Arroyo Seco 2

    Directory of Open Access Journals (Sweden)

    Figueiro, Gonzalo

    2007-01-01

    Full Text Available El análisis de ADN de restos antiguos permite agregar una dimensión diacrónica a estudios de historias poblacionales. Con el fin de estudiar la composición genética de una muestra temprana de la región pampeana, se extrajo y analizó por RFLP, ADN mitocondrial de una muestra de 23 individuos del sitio Arroyo Seco 2, Provincia de Buenos Aires, con fechados máximos de 7800 años A.P. Fue posible asignar 8 individuos a los haplogrupos B (n = 3, C (n = 4 y D (n = 1, en tanto que en 8 no pudo extraerse ADN, en 3 fue imposible la determinación y en 4 se constató contaminación con ADN moderno. Se exploraron las relaciones de muestras indígenas antiguas y modernas con la muestra de Arroyo Seco 2 que, como supuesto exploratorio inicial, fue considerada representativa de las poblaciones tempranas de la región pampeana. Entre los resultados obtenidos del análisis comparativo se destacan de momento: a Una relación sugerente entre la muestra de Arroyo Seco 2 y poblaciones modernas del Chaco, Patagonia y sur de Chile y b una notable diferencia respecto a los Mapuche de la Argentina, lo cual sugiere una discontinuidad entre las poblaciones pampeanas del Holoceno temprano y el Holoceno tardío.

  3. USO Y MANEJO DEL BOSQUE SECO TROPICAL PARA EL DESARROLLO SUSTENTABLE DE SANTA CATALINA DE ALEJANDRIA, BOLIVAR - COLOMBIA

    Directory of Open Access Journals (Sweden)

    Angela Cañon

    2016-03-01

    Full Text Available Como consecuencia de la acción humana, ha sido eliminado el 99% del bosque seco tropical del mundo, haciendo de este uno de los ecosistemas más amenazados del planeta. En el Caribe colombiano, el bosque seco tropical ocupaba aproximadamente la mitad del territorio, pero actualmente solo sobreviven algunos fragmentos aislados. En el municipio de Santa Catalina de Alejandría, en el norte del departamento de Bolívar, se encuentran reductos de bosque seco tropical de alto nivel de conservación y con una alta valoración biológica. Allí, la población local tiene un conocimiento especializado sobre los recursos de este ecosistema y deriva de ellos beneficios destacables. El artículo analiza los usos de estos fragmentos de bosque seco tropical, como resultado de los procesos históricos vividos en el municipio. Las relaciones de la población local con el bosque seco tropical en Santa Catalina de Alejandría son producto de la construcción histórica del territorio, que revelan el conocimiento y manejo especializado del bosque seco tropical por parte de campesinos y aparceros, como un camino para ser reconocido, valorizado y fortalecido, en el camino hacia el empoderamiento de la comunidad, el desarrollo sustentable y fortalecimiento de la sociedad civil, de la mano de la conservación de este valioso amenazado ecosistema. El artículo finaliza concluyendo que la conservación y utilización sustentable del bosque seco tropical puede ser incrementado si se tienen en cuenta los marcos que ofrece el Convenio de Diversidad Biológica y el Protocolo de Nagoya, de los cuales Colombia es signataria.

  4. Occurrence and biogenesis of seco-triterpenoids

    DEFF Research Database (Denmark)

    Almeida Robles, Aldo Ricardo

    in distantly related plant families hints that seco-triterpenoid pathways may result from convergent evolution. The hypothesis that seco-triterpenoids pathways evolve convergently was tested by studying the α-onocerin pathway in Ononis spinosa and Lycopodium clavatum. These led to the characterization of two...... OSCs in O. spinosa (OsONS1 and OsONS2) which both are able to produce α-onocerin. Contrary to the α-onocerin pathway in L. clavatum in which two different cyclases are needed for α-onocerin synthesis. Moreover, an OSC phylogenetic analysis indicated the onocerin synthases of O. spinosa arose from...... a different evolutionary route than those in L. clavatum. In addition, two squalene epoxidases (SQEs) of O. spinosa specialized for onocerin production were described and named OsSQE1 and OsSQE2. These SQEs displayed protein-protein interactions with OsONS1 and proved to boost the onocerin production of Os...

  5. seco-iridoids from Calycophyllum spruceanum (Rubiaceae).

    Science.gov (United States)

    Cardona Zuleta, Luz Margarita; Cavalheiro, Alberto José; Siqueira Silva, Dulce Helena; Furlan, Maysa; Marx Young, Maria Claudia; Albuquerque, Sérgio; Castro-Gamboa, Ian; da Silva Bolzani, Vanderlan

    2003-09-01

    Three seco-iridoids 7-methoxydiderroside, 6'-O-acetyldiderroside and 8-O-tigloyldiderroside, were isolated from the wood bark of Calycophyllum spruceanum together with the known iridoids loganetin, loganin and the seco-iridoids secoxyloganin, kingiside and diderroside. Their structures were elucidated by means of NMR and MS spectral data analysis. Using NOE correlations and coupling constants, the relative stereochemistry of the new derivatives was established. 7-Methoxydiderroside, 6'-O-acetyldiderroside and the known secoxyloganin and diderroside showed in vitro activity against trypomastigote forms of Trypanosoma cruzi, with IC(50) values of 59.0, 90.2, 74,2 and 84.9 microg/mL, respectively and were compared to the standard gentian violet (IC(50) 7.5 microg/ml).

  6. Estimación in vitro de gases con efecto invernadero en frutos y follaje de árboles de un bosque seco tropical de Venezuela In vitro estimation of greenhouse gases in tree fruits and foliage from a tropical dry forest of Venezuela

    Directory of Open Access Journals (Sweden)

    R Ramírez¹

    2012-03-01

    Full Text Available Con el objetivo de estimar la producción de gases con efecto invernadero (GEI en el follaje y los frutos de Calliandra cruegeri, Guazuma ulmifolia, Vachellia macracantha, Senna robiniifolia, Samanea saman, Lonchocarpus sp., Fagara sp., Senna espectabilis, Mangifera indica y Oyedaea verbesinoides, de un bosque seco tropical de Venezuela, se evaluaron estas especies a través de la técnica in vitro de producción de gas; se cuantificó la producción de ácidos grasos volátiles (AGV y se estimaron los GEI. Los sustratos que registraron una mayor producción (P<0,05 de metano (CH4 y dióxido de carbono (CO2 correspondieron a los frutos de S. saman (4,0 y 8,5, Fagara sp. (3,2 y 6,9 y G. ulmifolia (2,9 y 7,2, y al follaje de S. saman (3,6 y 8,2, S. robiniifolia (4,0 y 9,9 y V. macracantha (2,8 y 5,8. La menor cantidad (P<0,05 de CH4 y CO2 la produjeron los frutos de S. espectabilis (2,3 y 5,0 y Lonchocarpus sp. (2,3 y 5,9, y el follaje de: Fagara sp. (1,5 y 3,7, G. ulmifolia (1,4 y 3,5, C. cruegeri (1,6 y 4,0, M. indica (1,7 y 4,1, O. verbesinoides (1,8 y 4,2 y Cassia sp. (1,9 y 4,6. La producción de GEI y el tiempo de incubación estuvieron correlacionados con la producción de metano (r= 0,458; P<0,05. Se concluye que, de todas las especies, S. saman registró los mayores valores (P<0,05 de producción de GEI en los frutos y el follaje. Asimismo, entre las tres y ocho horas de incubación de los sustratos, la tasa de producción de GEI fue alta.

  7. Biodiversidad de los Valles Secos Interandinos del Ecuador. Anfibios y Reptiles.

    OpenAIRE

    Almendáriz,Ana

    2011-01-01

    Los bosques secos de la región Interandina del Ecuador se hallan ubicados en los sectores con el mayor número de asentamientos humanos tanto de tiempos pasados como de los actuales. La región Andina del Ecuador es la más deforestada del país; sin embargo, mantiene una flora Y fauna única y rica en especies que en la actualidad crece en lugares escarpados y poco accesibles.

  8. Oleoyl-estrone metabolic effects in relation with caloric restriction in inbred Beta rats with spontaneous obesity and type 2 diabetes Efectos metabólicos de la oleoil-estrona en relación con la restricción calórica en ratas Beta endocriadas, con obesidad espontánea y diabetes tipo II

    Directory of Open Access Journals (Sweden)

    Marta D. Posadas

    2004-08-01

    Full Text Available Spontaneously hypertriacylglycerolemic obese and diabetic inbred IIM Beta rats were treated with oleoyl- estrone for 10 days. Pair-feeding was performed to determine some oleoyl-estrone effects dependent on the caloric restriction it promotes. Twenty-five 200 day-old Beta males receiving a daily gavage of 0.2 ml sunflower oil were divided into the following groups: 1 daily dose of 10 nmol/g oleoyl-estrone; 2 pair-fed; 3 control. The variables measured were: whole body protein, water and lipid; retroperitoneal and epididymal fat depot weights; plasma urea, glucose, insulin, triacylglycerols and cholesterol. Biomass and food intake were assessed daily. Oleoyl-estrone and pair-fed groups expressed similar variations in body composition and significant body weight losses due to reduction in food intake. Oleoyl-estrone and pair-fed treatments significantly reduced retroperitoneal fat depot weights, but not epididymal ones. In oleoyl-estrone and pair-fed groups hyperglycemia decreased and insulinemia lowered significantly. Plasma normal total cholesterolemia and hypertriacylglycerolemia values typical of Beta rats decreased strongly compared to controls, though attaining significantly different values between oleoyl-estrone and pair-fed groups. Plasma total cholesterol appeared as more sensitive to caloric restriction than triacylglycerols through a specific oleoyl-estrone- mediated effect.Ratas endocriadas de la línea IIMBeta con obesidad, hipertriacilglicerolemia y diabetes espontáneas fueron tratadas con oleoil-estrona durante 10 días. Un grupo con restricción alimentaria fue incluido en el estudio a fin de aislar algunos efectos de la oleoil-estrona dependientes de la restricción calórica que ésta promueve. Veinticinco ratas Beta macho de 200 días de edad a los que se suministró 0.2 ml de aceite de girasol por día se dividieron en los siguientes grupos: (1 dosis diaria de 10 nmol/g de oleoil-estrona; (2 restringido; (3 control. Las

  9. COMPOSICIÓN DEL ENSAMBLE DE INSECTOS DEL DOSEL DE BOSQUES SUBTROPICALES SECOS DEL CHACO SEMIÁRIDO, ARGENTINA

    OpenAIRE

    Liliana Diodato; Andrea Fuster

    2016-01-01

    El dosel arbóreo constituye un complejo hábitat con gran diversidad de insectos. Los estudios sobre insectos del dosel están mayormente concentrados en bosques húmedos tropicales y son escasos en bosques secos subtropicales. El propósito de este trabajo fue caracterizar la entomofauna del dosel de bosques secos subtropicales, analizando su diversidad regional y localmente. Para ello se muestrearon cinco sitios localizados en la región fitogeográfica del Chaco Semiárido Argentino. Las recolecc...

  10. ANÁLISIS MOLECULAR DE LAS PRINCIPALES FAMILIAS DE ALÉRGENOS CAUSANTES DE LA ALERGIA ALIMENTARIA A FRUTOS SECOS

    OpenAIRE

    Moreno Serrano, José Antonio; Unidad de Bioquímica, Departamento de Biotecnología, E.T.S. Ingenieros Agrónomos, UPM, Madrid, España; Mejía Michay, Sandra Katerine; Universidad Nacional de Loja, Área de la Salud Humana, Loja, Ecuador

    2015-01-01

    La alergia alimentaria provocada por el consumo de frutos secos, está mediada por proteínas de transferencia de lípidos (LTPs) y Taumatinas (TLPs)  descritas como alérgenos de alimentos. El objetivo principal de este estudio fue establecer el papel de  LTPs y TLPs en el desarrollo de la alergia a castaña, avellana y nuez.Para el estudio de sensibilización a proteínas alérgicas de frutos secos, se utilizaron sueros de 13 pacientes con síntomas tras la ingestión de frutos secos, y prueba cutáne...

  11. Efectos de la pérdida de peso mediante una dieta muy baja en calorías (VLCD) sobre la pérdida de peso tras derivación biliopancreática en pacientes con obesidad severa

    OpenAIRE

    M. D. Ballesteros Pomar; R. Diez Rodríguez; A. Calleja Fernández; A. Vidal Casariego; Tomás González de Francisco; Luis González Herráez; Vicente Simó Fernández; S. Calleja Antolín; J. L. Olcoz Goñi; I. Cano Rodríguez

    2013-01-01

    Introducción: Se ha comunicado recientemente que la reducción de peso previa a cirugía bariátrica mediante dieta muy baja en calorías (VLCD) durante 2 semanas supone menor tasa de complicaciones postoperatorias. Es debatido, sin embargo, si la pérdida de peso preoperatoria con VLCD puede favorecer pérdida de peso postoperatoria. Objetivos: Valorar la eficacia de una VLCD, seguida durante 6 semanas preoperatorias, en el descenso de peso conseguido al año de la cirugía bariátrica. Evaluar los c...

  12. Interacciones entre semillas y escarabajos del estiércol (scarabaeinae en un bosque tropical seco

    Directory of Open Access Journals (Sweden)

    Julissa Ocampo-Castillo

    2018-01-01

    Full Text Available Los escarabajos del estiércol (Scarabaeinae son insectos importantes en muchos ecosistemas terrestres por susfunciones ecológicas, derivadas del comportamiento de remover las heces de vertebrados. Este grupo de insectoses particularmente abundante en los bosques tropicales (BT. Sus funciones ecológicas han sido principalmenteestudiadas en los BT húmedos, existiendo poca información para los BT secos. Se realizaron experimentos de campoen la Estación de Biología de Chamela (Jalisco, México durante la temporada de lluvias para cuantificar la remociónde heces por los escarabajos del estiércol y para evaluar sus interacciones con semillas durante la remoción deheces en un BT seco. A las 48 h la remoción de heces fue total; 71% de las semillas artificiales fueron enterradas entre0.5 y 30 cm de profundidad, y el 29% quedaron sobre la superficie pero dispersadas horizontalmente entre 1 y 150cm. El establecimiento de plántulas a partir del banco de semillas se vio favorecido por la presencia de heces y laactividad de los escarabajos del estiércol. Comparando nuestros resultados con aquellos obtenidos en bosquesNeotropicales húmedos, concluimos que en el BT seco estudiado las funciones ecológicas de los Scarabaeinae enla época de lluvias son similares a lo registrado en BT húmedos.

  13. Hormigas: relaciones especies-área en fragmentos de bosque seco tropical

    OpenAIRE

    Lozano-Zambrano, Fabio H; Ulloa-Chacón, Patricia; Armbrecht, Inge

    2009-01-01

    Analizamos el efecto de la fragmentación sobre las relaciones especies-área y frecuencia relativa-área de hormigas en nueve fragmentos de bosque seco tropical en la cuenca media del río Cauca, Colombia. La riqueza y frecuencia relativa total de hormigas se correlacionó positivamente con el área más no con el grado de aislamiento. Como la fragmentación afecta diferencialmente grupos funcionales, se encontró que según el hábitat que ocupan son más afectadas en su orden las especies que viven en...

  14. NOTAS SOBRE LOS ESCARABAJOS COPRÓFAGOS (COLEOPTERA: SCARABAEINAE) EN AMBIENTES SECOS DE LA REGIÓN DE SANTA MARTA, COLOMBIA

    OpenAIRE

    GARCIA HECTOR; MENDIETA WILLIAM; JIMENEZ FERBANS LARRY; AMAT GERMAN

    2008-01-01

    Se da a conocer la fauna de escarabajos coprófagos (Scarabaeinae) en cuatro tipos de hábitats con predominio del régimen seco. El método de colecta consistió en tran- sectos de trampas de caída cebadas con excremento humano. Se hallaron en total 26 especies, incluidas en 12 géneros. La riqueza más alta se presentó en el bosque seco con un menor impacto de las actividades humanas (18 especies) y la más baja (siete especies) en relictos de bosque seco ubicados en ambientes urbanos. El número de...

  15. Apuntes de Transmisión del Calor

    OpenAIRE

    Martín Domingo, Agustín

    2013-01-01

    Esta publicacion está basada en unos apuntes para la parte de Transmisión del Calor de las asignaturas de la ETSAM. Sin embargo, con el tiempo se ha añadido otro material extra que excede ampliamente el contenido del curso.

  16. El clima de las ciudades: isla de calor de Salamanca

    Directory of Open Access Journals (Sweden)

    Mª Salud Alonso García

    2004-12-01

    Full Text Available En este trabajo se ha determinado la existencia de la isla de calor urbana (ICU, en una ciudad de tamaño medio, con un clima extremado y focos industriales de poca actividad. Con lo que se puede comprobar cómo afecta el calentamiento urbano a ciudades de estas características, pudiendo influir en los seres vivos de la zona. La existencia del fenómeno isla de calor, y su evolución en el tiempo, se han observado comparando los datos de temperatura registrados en una estación meteorológica situada en la ciudad, con los de otra estación fuera del radio de acción de la urbe, durante el período 1996-1998. Se han detectado dos fenómenos: la isla de calor nocturna, cuando la diferencia térmica entre la ciudad y la zona rural es positiva, que presenta sus valores más altos en otoño, y la isla de calor diurna, cuando la diferencia es negativa, que presenta sus valores más altos en primavera. Realizando un estudio estadístico de la evolución anual de la isla de calor nocturna en Salamanca, podemos definir isla de calor débil si su intensidad es inferior a 2 oC, moderada si se encuentra entre 2 oC y 4 oC e intensa si supera los 4 oC.

  17. Determination of heat losses in the Cerro Prieto, Baja California, geothermal field steam transportation network based on the thermal insulation condition of the steam pipelines; Determinacion de perdidas de calor en la red de transporte de vapor del campo geotermico de Cerro Prieto, Baja California, con base en el estado fisico del aislamiento termico de vaporductos

    Energy Technology Data Exchange (ETDEWEB)

    Ovando Castelar, Rosember; Garcia Gutierrez, Alfonso; Martinez Estrella, Juan Ignacio [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: rovando@iie.org.mx; Canchola Felix, Ismael; Jacobo Galvan, Paul; Miranda Herrera, Carlos; Mora Perez, Othon [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Residencia General de Cerro Prieto, Mexicali, B.C. (Mexico)

    2011-07-15

    In Cerro Prieto Geothermal Field (CPGF), the steam from producing wells is transported to power plants through a large and complex system of pipes thermally insulated with a 2 inches thick mineral wool or a fiber glass layer and an external aluminum or iron cover. The insulation material has been exposed to weather conditions during the field operation and has suffered density and thickness changes. In some cases the insulation has been lost completely, increasing heat transfer from the pipes to the environment. This paper analyzes the impact of the conditions of thermal insulation on heat losses in the CPGF steam-pipeline network. The heat losses are calculated by applying an iterative method to determine the surface temperature based on a heat balance calculated from the three basic mechanisms of heat transfer: conduction, convection, and radiation. Finally, using length and diameter data corresponding to the condition of the thermal insulation of each pipeline-and field operation data, the overall heat losses are quantified for steam lines throughout the pipeline network in the field. The results allow us to evaluate the magnitude of the heat losses in comparison with the overall energy losses occurring during steam transport from wells to the power plants. [Spanish] En el Campo Geotermico de Cerro Prieto (CGCP), BC, el transporte de vapor desde los pozos hasta las plantas generadoras de electricidad se lleva a cabo mediante un extenso y complejo sistema de tuberias que tipicamente se encuentran aisladas termicamente con una capa de 2 pulgadas de material aislante a base de lana mineral o fibra de vidrio, y una proteccion mecanica de aluminio o hierro galvanizado. Debido a la exposicion a las condiciones meteorologicas a traves del tiempo de operacion del campo, el aislamiento ha experimentado cambios en su densidad y espesor y en ocasiones se ha perdido por completo, lo cual repercute en una mayor transferencia de calor de las tuberias hacia el medio ambiente

  18. Synthesis of the B-seco limonoid core scaffold

    Directory of Open Access Journals (Sweden)

    Hanna Bruss

    2014-01-01

    Full Text Available Synthetic investigations towards the structurally complex and highly decorated framework of B-seco limonoid natural products by means of a [3,3]-sigmatropic rearrangement are described. Detailed model studies reveal, that an Ireland–Claisen rearrangement can be employed to construct the central C9–C10 bond thereby giving access to the B-seco limonoid scaffold. However, application of the developed strategy ended up failing in more complex and sterically demanding systems.

  19. Synthesis of the B-seco limonoid core scaffold

    Science.gov (United States)

    Bruss, Hanna; Schuster, Hannah; Martinez, Rémi; Kaiser, Markus; Antonchick, Andrey P

    2014-01-01

    Summary Synthetic investigations towards the structurally complex and highly decorated framework of B-seco limonoid natural products by means of a [3,3]-sigmatropic rearrangement are described. Detailed model studies reveal, that an Ireland–Claisen rearrangement can be employed to construct the central C9–C10 bond thereby giving access to the B-seco limonoid scaffold. However, application of the developed strategy ended up failing in more complex and sterically demanding systems. PMID:24605139

  20. Heat pumping using the thermal earth gradient to produce air conditioned and hot water with savings of up to 70%; Bombeo de calor utilizando el gradiente termico de la tierra para producir aire acondicionado y agua caliente con ahorros de hasta un 70%

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez Ramirez, Alejandro [Novaenergia de Mexico S.A. de C.V. (Mexico)

    2003-07-01

    The pumping of heat using the Earth heat as partial energy source bases its principle on which the energy of the ground is constant and the energy efficiency to produce air conditioning and hot water simultaneously is important, obtaining savings up to 70%, comparing itself with the traditional equipment and what these operate of separated way to produce each one of them the cold air and the hot water. The use of this technology presents an opportunity to reduce the energy costs of and the demand of the company. [Spanish] El bombeo de calor utilizando el calor de la tierra como fuente parcial de energia basa su principio en que la energia del suelo es constante y el rendimiento energetico para producir simultaneamente aire acondicionado y agua caliente es importante, obteniendose ahorros hasta de un 70%, comparandose con los equipos tradicionales y que estos operan de manera separada para producir cada uno de ellos el aire frio y el agua caliente. El uso de esta tecnologia presenta una oportunidad para reducir los costos de energia y demanda de la empresa.

  1. Hombre, calor y aislamiento

    Directory of Open Access Journals (Sweden)

    Neutra, Richard J.

    1961-11-01

    Full Text Available Con los nuevos tipos estructurales y con los adelantos de las ciencias biológicas en lo que se refiere a los procesos orgánicos, mis ideas sobre aislamiento, y las de casi todos los demás arquitectos y constructores, han sufrido una evolución interesantísima en los últimos veinticinco años. Y me complace subrayar que los que, como yo, estudiamos el decorado humano, podemos hacer mucho en beneficio de nuestros clientes. No hace aún mucho tiempo toda la protección de una casa contra el peligro de transferencia térmica se confiaba exclusivamente a muros y cubiertas no aislantes. Los propietarios se limitaban a culpar al tiempo de su falta de confort. Pero esta falta de comodidad en cuanto a calefacción no era la única consecuencia; tras ella aparecían daños de efectos duraderos y patológicos.

  2. Incremento de la productividad por recuperación de calor en gases de chimenea de un horno de cubilote

    OpenAIRE

    Mejía Arango, Héctor Daniel; Silva, Claudia; Aristizábal Sierra, Ricardo Emilio

    2003-01-01

    Sobre la base de la primera ley de la termodinámica se realiza el balance de calor para dos cubilotes típicos y para el cubilote de la Universidad de Antioquia, en este último, antes y después de ser instalado y puesto a punto el sistema de recuperación de calor, que opera con dos regeneradores de lecho empacado. Con los resultados obtenidos en el prototipo eco-eficiente se demuestran las ventajas de trabajar un cubilote con sistemas que recuperen calor de los gases de chimenea, resaltando en...

  3. Elementi di trasmissione del calore

    CERN Document Server

    Guglielmini, Giovanni

    1990-01-01

    Introduzione ; concetti fondamentali di conduzione termica ; conduzione termica in regime stazionario ; conduzione termica in regime variabile ; analisi numerica nei problemi do conduzione ; concetti fondamentali di convezione termica ; convezione forzata ; convezione naturale ; scambio termico in ebollizione e condensazione ; concetti fondamentali di radiazione termica ; scambio termico per radiazione ; scambiatori di calore ; problemi termici negli edifici.

  4. Creación de instrucciones de trabajo para mantenimiento de líneas propulsoras en dique seco en un astillero de súper yates.

    OpenAIRE

    Ros Almirall, José María

    2014-01-01

    El objetivo de este proyecto final de carrera es poder hacer unas instrucciones de trabajo para realización de trabajos de dique seco en un astillero de yates de grande eslora. Dentro de toda la diversidad de trabajos que se pueden realizar en dique seco, nos centraremos en la línea propulsora, desde el acople con el volante de la reductora hasta la hélice de propulsión. Mediante el uso de estas instrucciones los operarios y los jefes de buque o directores de proyecto, encargados del segui...

  5. Evaluación del rendimiento de grano seco en accesiones promisorias de Plukenetia volubilis “sacha inchi” en Loreto

    Directory of Open Access Journals (Sweden)

    Andrés Fernández-Sandoval

    2013-06-01

    Full Text Available El sacha inchi es una especie vegetal oleaginosa que se encuentra al estado silvestre en selva alta, baja y ceja de selva del Perú. Es importante por su alto contenido de ácidos grasos insaturados (aceites omegas y proteínas que contienen las semillas que lo hace ideal para mejorar la dieta alimenticia humana. El Gobierno Regional ha priorizado el cultivo de sacha inchi para impulsar el desarrollo económico y social de sus productores. Los trabajos de evaluación de rendimiento de grano seco de sacha inchi bajo condiciones de selva baja, se realizaron en el Campo Experimental El Dorado de la EEA. San Roque- INIA; con 9 accesiones provenientes del banco de germoplasma de la EEA. El Porvenir, Tarapoto. El objetivo de esta investigación fue evaluar el rendimiento de grano seco y validar y adaptar la tecnología de producción de esta especie en condiciones de selva baja. Las accesiones que sobresalieron fueron Barranquita y Cumbaza, con rendimientos de 1863 y 1809 kg/ha de grano seco por hectárea. La accesión Tambo Yaguas, obtuvo el rendimiento más bajo con 631 kg/ha de grano seco por hectárea, debido principalmente a su susceptibilidad a Rhizoctonia sp. “Mustia hilachoza”.

  6. The seco-iridoid pathway from Catharanthus roseus.

    Science.gov (United States)

    Miettinen, Karel; Dong, Lemeng; Navrot, Nicolas; Schneider, Thomas; Burlat, Vincent; Pollier, Jacob; Woittiez, Lotte; van der Krol, Sander; Lugan, Raphaël; Ilc, Tina; Verpoorte, Robert; Oksman-Caldentey, Kirsi-Marja; Martinoia, Enrico; Bouwmeester, Harro; Goossens, Alain; Memelink, Johan; Werck-Reichhart, Danièle

    2014-04-07

    The (seco)iridoids and their derivatives, the monoterpenoid indole alkaloids (MIAs), form two large families of plant-derived bioactive compounds with a wide spectrum of high-value pharmacological and insect-repellent activities. Vinblastine and vincristine, MIAs used as anticancer drugs, are produced by Catharanthus roseus in extremely low levels, leading to high market prices and poor availability. Their biotechnological production is hampered by the fragmentary knowledge of their biosynthesis. Here we report the discovery of the last four missing steps of the (seco)iridoid biosynthesis pathway. Expression of the eight genes encoding this pathway, together with two genes boosting precursor formation and two downstream alkaloid biosynthesis genes, in an alternative plant host, allows the heterologous production of the complex MIA strictosidine. This confirms the functionality of all enzymes of the pathway and highlights their utility for synthetic biology programmes towards a sustainable biotechnological production of valuable (seco)iridoids and alkaloids with pharmaceutical and agricultural applications.

  7. Reparación de un dique seco en el Ferrol/España

    Directory of Open Access Journals (Sweden)

    Navas Gutiérrez, Mariano

    1981-06-01

    Full Text Available El dique seco de El Ferrol, construido como dique de gravedad según la técnica de la época (1913, ha sufrido una serie de averías como consecuencia de su envejecimiento, que ha obligado a emprender una obra de reparación según las modernas técnicas de soleras ancladas y drenadas, y pantallas de bentonita-cemento. Se ha construido una losa de 30 cm en el antedique, anclada con armaduras activas, formado cada anclaje por diez cables según una malla de 3 x 3 m. Para aliviar la subpresión se ha colocado un dren entre la solera permeable actualmente existente y la losa. Con la pantalla de bentonita-cemento se pretende cerrar la entrada de agua por el relleno permeable del antiguo dique. El terreno natural es prácticamente impermeable.

  8. Tratamiento terapéutico térmico en el Síndrome de Ojo Seco

    OpenAIRE

    Osuna Montes, Virginia María

    2017-01-01

    El Síndrome de Ojos Secos (SOS) es una enfermedad multifactorial, su principal motivo es la Disfunción de la Glándula de Meibomio (DGM), siendo la causa más frecuente de consulta oftalmológica. Con las últimas innovaciones de tratamiento se ha visto que puede mejorar la calidad de vida de estos pacientes. Nuestro objetivo es identificar la efectividad de los tratamientos terapéuticos térmicos en pacientes con SOS. Hacemos una revisión bibliográfica de artículos científicos obtenidos en las si...

  9. Capacidad productiva de praderas mono-específica, asociada y silvopastoril en un ambiente tropical seco.

    OpenAIRE

    Jiménez Guillén, Régulo

    2012-01-01

    Esta investigación tuvo como objetivo describir las características edáficas, del forraje y la respuesta productiva de bovinos, en tres tipos de pradera para un ambiente tropical seco. Los tratamientos fueron praderas con: A) Andropogon gayanus; A+C) A. gayanus y Clitoria ternatea y A+C+M) A. gayanus, C. ternatea y Morus alba. En la época de lluvias el forraje ofrecido, residual y desaparecido, fue diferente (P0.05) entre los tres tratamientos. Con relación a la respuesta animal en la época ...

  10. Propiedades antioxidantes de los frutos secos y la disminución del colesterol total y LDL- colesterol

    OpenAIRE

    Raquel López León; Jessica Ureña Solís

    2012-01-01

    Objetivo: Disminuir el colesterol total y el LDL colesterol mediante el consumo de frutos secos (maní, nuez y almendras) con propiedades antioxidantes para reducir el riesgo de enfermedades cardiovasculares. Método: El presente trabajo es cuantitativo transversal, cuasi-experimental. Se tomó una muestra de 45 participantes del Instituto Interamericano de Cooperación para la Agricultura (IICA), ambos sexos, entre 18 y 65 años de edad, con hipercolesterolemia total mayor a 200 mg/dL y LDL-coles...

  11. Modelado matemático de la transferencia de calor y materia y de la presión durante la deshidratación con microondas de alimentos como medios porosos

    OpenAIRE

    Arballo, Javier Ramiro; Campañone, Laura Analia; Mascheroni, Rodolfo Horacio

    2016-01-01

    Estudios recientes han sido dedicados al desarrollo de modelos matemáticos para simular el procesamiento de alimentos utilizando el enfoque de medios porosos (enfoque mecanístico). El objetivo de este estudio es simular la deshidratación con microondas por medio del modelado de la transferencia de materia y energía usando el enfoque mecanístico. La deshidratación con microondas involucra mecanismos físicos complejos que deben ser considerados en la formulación del modelo matemático completo. ...

  12. DESHIDRATACION Y SOBREHIDRATACION VOLUNTARIAS DURANTE EL EJERCICIO EN EL CALOR: POSIBLES FACTORES RELACIONADOS

    Directory of Open Access Journals (Sweden)

    Andrea Solera Herrera

    2006-12-01

    Full Text Available Los efectos negativos de la deshidratación sobre la salud y el rendimiento han sido bien documentados. Recientemente, también se han documentado problemas por sobrehidratación. La presente investigación se hizo para estudiar los posibles factores que influyen sobre la ingesta voluntaria de líquido durante el ejercicio y determinar si existe relación entre el grado de deshidratación voluntaria y la creencia de que la ingesta de líquido provoca cólico. Para ello, se contó con 94 estudiantes universitarios jóvenes, varones, quienes se ejercitaron a un 60% de su FCmáx durante una hora, alternando cada 10 min. entre bicicleta estacionaria, subir y bajar un escalón, y una máquina simuladora de esquí. Esto se realizó en un laboratorio de ambiente controlado a 30úC, 70% humedad relativa. Durante el ejercicio se midió la ingesta voluntaria de una bebida deportiva, así como también las percepciones de calor ambiental, llenura estomacal, malestar gastrointestinal y palatabilidad de la bebida. Los sujetos fueron pesados desnudos y secos antes y después del ejercicio. Al final se les aplicó un cuestionario sobre la importancia de la hidratación, y sus creencias sobre el cólico. El equilibrio hídrico promedio fue de 0.14 ± 0.98% del peso corporal, con un rango entre -2.38% y 2.84%. La tasa de sudoración promedio fue de 1208.3 ± 381.7ml·h-1; y la ingesta de 1132 ± 610ml·h-1. Dos análisis de regresión múltiple determinaron que: (a los predictores más fuertes de la ingesta voluntaria de líquido fueron la importancia asignada a la hidratación durante el ejercicio (R2 = 0.13; p < 0.0005 y la percepción de llenura estomacal al minuto 25 (R2 = 0.08; p = 0.005; (b los predictores más fuertes del equilibrio hídrico fueron la ingesta voluntaria por kg de peso (R2 = 0.73; p < 0.0005, y la tasa de sudoración (R2 = 0.08; p = 0.006. No obstante, el equilibrio hídrico no estuvo asociado con ninguna de las percepciones, ni con las

  13. Prácticas de Física: Equivalente en agua de un calorímetro

    OpenAIRE

    Beléndez,Augusto; Bernabeu, Guillermo; Vera Guarinos, Jenaro; Pastor Antón, Carlos; Martín García, Agapito

    1988-01-01

    Esta práctica de laboratorio tiene como objetivo el cálculo del equivalente en agua de un calorímetro con su error, familiarizarse con el uso del mismo y del termómetro. Para el desarrollo de esta práctica se dispone de un calorímetro lleno de agua en el que se ha colocado una resistencia interna. Se hace circular una corriente por la resistencia, de manera que la potencia que disipa la resistencia se convierte en potencia calorífica, por efecto Joule, calentando por un lado el agua en el int...

  14. The seco-iridoid pathway from Catharanthus roseus

    NARCIS (Netherlands)

    Miettinen, K.; Dong, L.; Navrot, N.; Burlat, V.; Schneider, T.; Pollier, J.; Woittiez, L.S.; Krol, van der A.R.; Lugan, R.; Llc, T.; Verpoorte, R.; Oksman-Caldentey, K.M.; Martinoia, E.; Bouwmeester, H.J.

    2014-01-01

    The (seco)iridoids and their derivatives, the monoterpenoid indole alkaloids (MIAs), form two large families of plant-derived bioactive compounds with a wide spectrum of high-value pharmacological and insect-repellent activities. Vinblastine and vincristine, MIAs used as anticancer drugs, are

  15. Caracterización de las Diatomitas de Río Seco (Piura, Perú

    Directory of Open Access Journals (Sweden)

    Rodríguez Lichtenheldt, J.

    1998-10-01

    Full Text Available The occurrence of diatomites on the area of Rio Seco (Piura, Peru, has led the authors to study their physical, chemical and mineralogical properties with the aim to determinate their principal uses and applications. Conventional methods were applied besides of optical and electronical microscopy, difraction of X rays and thermal differential and gravimetric analysis. It is a medium quality material because of their silica and alumina contents, then the applications should be limited to fabrication of puzzolanic and ceramic materials for construction.

    La existencia de diatomita en la zona de Río Seco (Piura, Perú, ha llevado a los autores a realizar un estudio de sus propiedades físicas, químicas y mineralógicas, con el objeto de determinar sus principales usos y aplicaciones. Para ello se han utilizado las técnicas de análisis convencional, así como microscopia óptica y electrónica, difracción de rayos X y análisis térmico diferencial y gravimétrico. Tratándose de un material de calidad media, por los contenidos en sílice y alúmina que presenta, su aplicación quedaría restringida a la fabricación de materiales puzolánicos y cerámicos para la construcción.

  16. DESARROLLOS INSTRUMENTALES EN MICROCALORIMETRIA DE CONDUCCIÓN DE CALOR

    Directory of Open Access Journals (Sweden)

    Liliana Giraldo G.

    2010-09-01

    Full Text Available Se presentan aspectos generales de la microcalorimetría de conducción de calor. Se describe el diseño y la operación de microcalorímetros de conducción de calor estático y de flujo construidos en este laboratorio, los cuales fueron calibrados eléctrica y químicamente. Estos equipos se emplean en la caracterización de sólidos porosos por la técnica de calorimetría de inmersión y en la determinación de entalpias de transferencia de solutos; su uso se ilustra con algunos resultados típicos. Se mencionan además otras aplicaciones que se dan actualmente a estos aparatos.

  17. Diversidad, composición y estructura de un hábitat altamente amenazado: los bosques estacionalmente secos de Tarapoto, Perú

    Directory of Open Access Journals (Sweden)

    Roosevelt García-Villacorta

    2011-07-01

    Full Text Available Entre marzo y abril de 2006, la flora de los bosques estacionalmente secos en Tarapoto, San Martín fue estudiada en diez localidades. En cada una de estas localidades se estableció una parcela de 0,1 ha; cada tallo mayor de 2,5 cm de diámetro fue medido, contado e identificado a especie. Se encontraron 146 especies en 2814 individuos. En toda la zona de estudio, Myrtaceae fue la familia más diversa con 14 especies, seguida por Leguminosae con 12 especies. Igualmente, Annonaceae y Myrtaceae fueron las familias más abundantes en numero de tallos en toda la zona de estudio (461, y 412 tallos totales, mientras que Sapotaceae, con sólo 160 tallos totales, tuvo el valor más alto en área basal, debido a la Quinilla, Manilkara bidentata (A. DC. A. Chev., el árbol más importante en la estructura de los bosques estacionalmente secos de Tarapoto. Dos especies estuvieron presentes en todos los sitios de estudio: Coccoloba sp. 1, (Polygonaceae y Oxandra espintana (Spruce ex Benth. Baill. (Annonaceae, mientras que 53 especies ocurrieron en un solo sitio. Los bosques estacionalmente secos de Tarapoto presentan una diversidad intermedia comparada con otros bosques secos del Neotrópico y similar diversidad a los bosques secos del Pacífico Peruano. La comunidad de árboles en estos bosques pertenece a especies de amplia distribución comparada con las especies de arbustos que tienen distribución restringida a los hábitats de bosques secos. En términos generales las áreas localizadas cerca de la carretera Tarapoto-Juanjui tienen el grado más alto de amenaza y perturbación debido a la extracción maderera y destrucción de hábitat para la creación de campos de cultivos agrícolas. Los bosques más representativos y mejor conservados de esta región se encuentran al Oeste y Sur de Picota, en el Área de Conservación Municipal El Quinillal, y en la cuenca del Río Bombonajillo y Ponasillo. Estos resultados resaltan la urgencia de conservar estos

  18. Carnot to Clausius: Caloric to Entropy

    Science.gov (United States)

    Newburgh, Ronald

    2009-01-01

    This paper discusses how the Carnot engine led to the formulation of the second law of thermodynamics and entropy. The operation of the engine is analysed both in terms of heat as the caloric fluid and heat as a form of energy. A keystone of Carnot's thinking was the absolute conservation of caloric. Although the Carnot analysis was partly…

  19. Higher Unsaturation and Peroxidizability Indices in Caloric ...

    African Journals Online (AJOL)

    In this report, Drosophila melanogaster were maintained on caloric restricted and normal diets for varying periods, mitochondrial phospholipid fatty acids were extracted and analyzed. Whilst 10 days and 20 days of caloric restriction did not cause any significant change in mitochondrial phospholipid fatty acid composition, ...

  20. Vulnerabilidad geotécnica de las quebradas Arroyo Seco y Puca Puca en la ciudad de Ayacucho

    OpenAIRE

    Narváez López, Roberto

    2012-01-01

    En este trabajo se realizó mapas de vulnerabilidad para la cuenca de la Quebrada arroyo seco y sus aportantes Puca Puca, Islachayocc, Pilacucho, que forma parte de la cuenca del Río alameda. Las altas precipitaciones, la topografía y la sismicidad constituyen los principales factores que conducen a la constante ocurrencia de colapsos del terreno que afectan a los habitantes y la infraestructura de la región. Con el fin de controlar, corregir y preservar la estabilidad de la cuenca, la inform...

  1. Enfriamiento de café pergamino seco a granel utilizando aireación mecánica controlada

    OpenAIRE

    Julio E. Ospina M.; Mery Cecilia Cruz; Ricardo A. Trejos

    2011-01-01

    Con el fin de garantizar que el café almacenado a granel conserve su calidad durante el tiempo necesario de almacenamiento, se estudió el enfriamiento del café pergamino seco en silos experimentales de dimensiones: 0.5m x 0.5m y 2.8 m de altura, utilizando aire enfriado mecánicamente. Los rangos estudiados fueron: temperatura de 10 a 220C humedad relativa de 66 a 98%y contenido de humedad del grano de 8 a 13.57% b.h. Durante la etapa de almacenamiento se evaluó la variación de la calidad del ...

  2. Uso y verificación con indicadores biológicos en esterilizadores de cirujanos dentistas de San Luis Potosí, México

    Directory of Open Access Journals (Sweden)

    Patiño-Marín Nuria

    2001-01-01

    Full Text Available Objetivo. Conocer el uso y verificar los ciclos de esterilización con indicadores biológicos en los equipos utilizados por cirujanos dentistas de la Facultad de Estomatología de la Universidad Autónoma de San Luis Potosí (UASLP y del Colegio Dental Potosino. Material y métodos. Estudio transversal hecho en 1999-2000. El 65% (n=130 de los odontólogos participaron con un esterilizador, la verificación se realizó por indicadores que contenían esporas de Bacillus subtilis y de Bacillus stearothermophilus. Resultados. Participaron 30 autoclaves y 100 esterilizadores de calor seco, 23 de ellos (17.7% presentaron crecimiento bacteriano; el 16.1% (n=21 de los participantes utilizan los indicadores biológicos como verificador. Los dos métodos de esterilización presentaron crecimiento bacteriano con frecuencias similares (p=>0.66. Conclusiones. Pocos cirujanos dentistas verifican su esterilizador con indicadores biológicos en los equipos que presentaron crecimiento bacteriano, sus fallas se encontraron en el proceso de esterilización. El texto completo en inglés de este artículo está disponible en: http://www.insp.mx/salud/index.html

  3. Caloric beverage consumption patterns in Mexican children

    Directory of Open Access Journals (Sweden)

    Rivera Juan A

    2010-10-01

    Full Text Available Abstract Background Mexico has seen a very steep increase in child obesity level. Little is known about caloric beverage intake in this country as well as all other countries outside a few high income countries. This study examines overall patterns and trends in all caloric beverages from two nationally representative surveys from Mexico. Methods The two nationally representative dietary intake surveys (1999 and 2006 from Mexico are used to study caloric beverage intake in 17, 215 children. The volume (ml and caloric energy (kcal contributed by all beverages consumed by the sample subjects were measured. Results are weighted to be nationally representative. Results The trends from the dietary intake surveys showed very large increases in caloric beverages among pre-school and school children. The contribution of whole milk and sugar-sweetened juices was an important finding. Mexican pre-school children consumed 27.8% of their energy from caloric beverages in 2006 and school children consumed 20.7% of their energy from caloric beverages during the same time. The three major categories of beverage intake are whole milk, fruit juice with various sugar and water combinations and carbonated and noncarbonated sugared-beverages. Conclusion The Mexican government, greatly concerned about obesity, has identified the large increase in caloric beverages from whole milk, juices and soft drinks as a key target and is initiating major changes to address this problem. They have already used the data to shift 20 million persons in their welfare and feeding programs from whole to 1.5% fat milk and in a year will shift to nonfat milk. They are using these data to revise school beverage policies and national regulations and taxation policies related to an array of less healthful caloric beverages.

  4. Colapso pelo calor esforço induzido: reconhecimento para salvar vidas e tratamento imediato em instalações atléticas Choque térmico relacionado con el ejercício: reconocimiento y tratamiento locales para salvar vidas Exertional heat stroke: life-saving recognition and onsite treatment in athletic settings

    Directory of Open Access Journals (Sweden)

    2005-12-01

    Full Text Available O prognóstico do colapso pelo calor esforço induzido depende do produto do tempo de duração em que a temperatura central ficou elevada e do grau da elevação. O atleta com EHS que tem pronta descoberta e que é resfriado de maneira eficiente, muito provavelmente irá sobreviver ao episódio com pouco ou nenhum efeito residual. Em contraste, o atleta com apresentação atrasada para o tratamento, especialmente se a área sob a curva de resfriamento for > 60 graus-minuto (centígrados terá um curso complicado e geralmente fatal. Os métodos de condução do resfriamento com imersão em gelo ou água gelada ou envolvimento em toalhas com água gelada proporcionarão uma rápida e consistente redução da temperatura de todo o corpo, que irá salvar tanto os órgãos quanto a vida. O reconhecimento depende em alto grau da suspeita por parte dos próprios atletas, treinadores e pessoal médico local. Em condições de alto risco, os atletas devem se supervisionar, procurando por mudanças sutis que podem ser sinais de EHS.El pronóstico del choque térmico (CT relacionado con el ejercicio depende del producto del periodo de tiempo en que la temperatura central se mantenga elevada y de la magnitud de esta elevación. El atleta con CT que sea diagnosticado y sea rápida y eficientemente refrescado probablemente sobrevivirá al episodio con ninguna o pocas complicaciones. Por otra parte aquel atleta que halla tenido un inicio tardío en el tratamiento con una área por debajo de la curva mayor de 60 grados-minuto (centigrados tendrá complicaciones y de seguro una evolución fatal. Los métodos de enfriamiento con hielo o inmersión en agua fría o toallas con agua helada en rotación permiten una reducción consistente y rápida de la temperatura corporal capaz de preservar los órganos y la vida. El reconocimiento depende del elevado grado de sospecha por parte de los atletas, técnicos y personal de apoyo médico. En condiciones de alto riesgo

  5. Abundancia, diversidad y categoría ecológica de los peces en estero damas y estero palo seco, Costa Rica

    Directory of Open Access Journals (Sweden)

    Hubert Araya

    2016-03-01

    Full Text Available Se trabajó de junio de 1986 a febrero de 1987 en una estación de muestreo en el estero Palo Seco y en dos en el estero Damas (Damas y San Bosco, Pacífico Central, Costa Rica. La temperatura del agua no presentó diferencias significativas entre las estaciones Damas y San Bosco, pero sí entre Damas-Palo Seco y San Bosco-Palo Seco. La salinidad varió significativamente entre las tres estaciones y el pH no mostró diferencias significativas. Se recolectaron representantes de 25 familias, 39 géneros y 54 especies. De las especies, 18 comparten los tres sitios de muestreo, siete se hallaron únicamente en Palo Seco, cinco en Damas y seis en San Bosco. De las especies recolectadas, el 7,41% es compartido entre Palo Seco y Damas; el 3,70% entre Palo Seco y San Bosco y el 22,22% entre Damas y San Bosco. El análisis de similitud determinó que las estaciones Damas y San Bosco comparten un 41,40% de las especies; mientras que Palo Seco solamente presento un 9,9% de especies comunes con el grupo Damas-San Bosco. La mayoría de las especies encontradas fueron de origen marino que utilizan estos dos esteros como área de crianza (42,59% y alimentación (40,74%; mientras que las de agua dulce, estuarinas y visitantes ocasionales están poco representadas. La mayor diversidad se encontró en San Bosco y se detectaron diferencias estadísticamente significativas en los valores de H' entre las estaciones. La mayor similitud de especies se presentó entre las estaciones Damas y San Bosco, lo que sugiere que estas áreas están bajo una mayor influencia de aguas continentales; lo que propicia que los peces estén más ampliamente distribuidos. Se deduce que la ictiofauna de los esteros estudiados es transitoria en los sitios de muestreo y que la misma se distribuye heterogéneamente.

  6. Oxytocin reduces caloric intake in men

    National Research Council Canada - National Science Library

    Lawson, Elizabeth A; Marengi, Dean A; DeSanti, Rebecca L; Holmes, Tara M; Schoenfeld, David A; Tolley, Christiane J

    2015-01-01

    .... Oxytocin effects on nutrition and metabolism in humans are not well defined. It was hypothesized that oxytocin would reduce caloric intake and appetite and alter levels of appetite-regulating hormones...

  7. Epigenetic regulation of caloric restriction in aging

    National Research Council Canada - National Science Library

    Li, Yuanyuan; Daniel, Michael; Tollefsbol, Trygve O

    2011-01-01

    .... The aging process is frequently affected by environmental factors, and caloric restriction is by far the most effective and established environmental manipulation for extending lifespan in various animal models...

  8. Olho seco: etiopatogenia e tratamento Dry eye: etiopathogenesis and treatment

    Directory of Open Access Journals (Sweden)

    Ellen Carrara Fonseca

    2010-04-01

    Full Text Available Olho seco é uma doença multifatorial das lágrimas e da superfície ocular que resulta em desconforto, distúrbios visuais e instabilidade do filme lacrimal. É uma desordem comum que afeta principalmente adultos e mulheres e que pode causar impacto na qualidade de vida comparável a enxaqueca, dispnéia e insuficiência renal crônica, dependendo dos sintomas ou complicações que a acompanham. Novos conceitos com relação à fisiopatologia, classificação e tratamento têm sido apresentados e devem ser conhecidos pelos oftalmologistas pela sua larga aplicação no dia-a-dia. Estima-se que haja 100 medicações diferentes em uso para olho seco atualmente, além de outros métodos de tratamento, sendo necessário se estabelecer o que é realmente seguro e eficaz. Este texto faz uma revisão sobre etiopatogênese e tratamento da síndrome do Olho Seco.Dry eye is a multifactorial disease of tears and ocular surface that causes discomfort, visual disturbance and tear film instability. It is a common disorder that affects specially adults and women and can cause quality of life impairment comparable to migraine, shortness of breath and chronic renal insufficiency, depending on its symptoms or complications. New concepts regarding physiopathology, classification and treatment have been presented and should be known by ophthalmologists because of their relevance on day-by-day application. There are about 100 different medications currently in use for dry eye besides other methods of treatment, so it is necessary to establish what is really safe and effective for dry eye. This paper presents a review about Dry Eye Syndrome etiopathogenesis and treatment.

  9. Fasting or caloric restriction for healthy aging.

    Science.gov (United States)

    Anton, Stephen; Leeuwenburgh, Christiaan

    2013-10-01

    Aging is associated with a host of biological changes that contribute to a progressive decline in cognitive and physical function, ultimately leading to a loss of independence, and increased risk of mortality. To date, prolonged caloric restriction (i.e., a reduction in caloric intake without malnutrition) is the only non-genetic intervention that has consistently been found to extend both mean and maximal life span across a variety of species. Most individuals have difficulty sustaining prolonged caloric restriction, which has led to a search for alternative approaches that can produce similar to benefits as caloric restriction. A growing body of evidence indicates that fasting periods and intermittent fasting regimens in particular can trigger similar biological pathways as caloric restriction. For this reason, there is increasing scientific interest in further exploring the biological and metabolic effects of intermittent fasting periods, as well as whether long-term compliance may be improved by this type of dietary approach. This special will highlight the latest scientific findings related to the effects of both caloric restriction and intermittent fasting across various species including yeast, fruit flies, worms, rodents, primates, and humans. A specific emphasis is placed on translational research with findings from basic bench to bedside reviewed and practical clinical implications discussed. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Los árboles en la ganadería del trópico seco

    Directory of Open Access Journals (Sweden)

    J. M. Palma

    2005-01-01

    Full Text Available En el presente trabajo se resalta la presencia de árboles en los sistemas ganaderos del estado de Colima, México; lugar en donde las características climáticas predominantes son de trópico seco. Se enfatiza la importancia de la vegetación arbórea nativa, tanto de especies leguminosas como no leguminosas, manejadas ya sea en forma empírica como científica de algunos sistemas silvopastoriles (SSP presentes en la región. Destacan las características nutricionales tanto del follaje como de los frutos, con la descripción de algunos SSP; entre ellos, el manejo del cocotero en la región costera, los árboles en los potreros, experiencias con el manejo de los bancos de proteína, la utilización de cercas vivas y algunas asociaciones forrajeras. Destaca la diversidad de árboles susceptibles de ser incorporados en el desarrollo de sistemas silvopastoriles, así como la necesidad de generar una cultura para la conservación y multiplicación de estas especies, sobre todo en ambientes en donde la deforestación y la erosión son una amenaza.

  11. Aislamiento térmico producido a partir de cascarilla de arroz aglomerada utilizando almidón producido con saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Jaime Gutiérrez M.D.

    2014-01-01

    Full Text Available Se aglomeró cascarilla de arroz usando almidones con el fin de obtener un material con estabilidad física adecuada, sin afectar su capacidad aislante. Para esto, se desarrolló un proceso que integró Saccharomyces Cerevisiae (SC como elemento productor de porosidades en el material. Posteriormente se sometieron las probetas a pruebas de resistencia al calor, flexión y finalmente a la norma ASTM C 177, para evaluar su conductividad térmica. De esta forma, se encontró que el aglomerado al ser sometido a fuego directo no produce llama (ignifugo, tiene una resistencia a la rotura entre 80 – 120 kPa al ser sometido a temperaturas entre 150 y 200 °C, la conductividad térmica del aglomerado se encuentra alrededor de 0,09 W/m.K. El aglomerado se dejó a la intemperie (Temperatura de bulbo seco: 30°C ± 5°C, Humedad relativa: 80% ± 15%, donde su estabilidad química se aprecia al no ser atacado por hongos, y su biodegradabilidad se manifiesta al ser disuelto por agua. Estos valores muestran que el aglomerado a base de cascarilla de arroz es un aislante térmico eficiente, con una estabilidad física y química adecuada para aplicaciones civiles.

  12. REPTILES DEL VALLE SECO DEL RÍO MAGDALENA (HUILA, COLOMBIA

    Directory of Open Access Journals (Sweden)

    RAFAEL MORENO-ARIAS

    2015-06-01

    Full Text Available Se presenta una caracterización de la fauna de reptiles del valle seco del río Magdalena en el departamento del Huila, así como la comparación faunística entre unidades de cobertura vegetal y épocas climáticas. Se registraron 31 especies pertenecientes a 30 géneros, 17 familias y dos órdenes. En el orden Squamata, la familia más diversa fue Teiidae (lagartijas con tres especies y Colubridae (serpientes con nueve. Para el orden Testudines se registró una especie. Con base en curvas de acumulación de especies y los estimadores no paramétricos Jackknife 2 y Bootstrap, para las lagartijas se obtuvo una alta representatividad en el muestreo (83% y 92% respectivamente, mientras que para las serpientes fue menor (75% y 82% respectivamente. La estructura y composición de los ensambles de reptiles en cada unidad de cobertura vegetal no fue significativamente diferente, en general se caracterizaron por presentar pocas especies con muchos individuos y numerosas especies raras. El arbustal presentó la mayor riqueza de especies seguido del bosque de ribera y los cultivos de cacao. En general la abundancia de reptiles fue mayor en la época de lluvias que en la época seca, sin embargo la manera en que responden las especies a las épocas climáticas está dada por sus características ecológicas, fisiológicas y comportamentales.

  13. CRECIMIENTO Y DESARROLLO DE LA LIMA ÁCIDA (Citrus latifolia Tanaka, cv. Tahití, EN SUELOS CON LIMITACIONES POR PROFUNDIDAD EFECTIVA, EN UN BOSQUE SECO TROPICAL GROWTH AND DEVELOPMENT OF LIME (Citrus latifolia Tanaka, cv. Tahiti, IN SOILS WITH LIMITATIONS BY EFFECTIVE DEPTH IN A TROPICAL DRY FOREST

    Directory of Open Access Journals (Sweden)

    Gabriel Fernando Ochoa Agudelo

    2012-06-01

    Full Text Available Resumen. Se evaluó la evolución de la biomasa, la distribución diferencial de ésta entre los órganos y algunos parámetros del crecimiento y desarrollo, de la lima ácida (Citrus latifolia Tanaka, cv. Tahití, injertada sobre Carrizo y Kryder. El cultivo se estableció en suelos con limitaciones por profundidad efectiva (PE entre 10 y 20 cm; las evaluaciones se realizaron a los 24, 32 y 39 meses después del trasplante. Se debe tener presente que el crecimiento de las raíces está condicionado a los atributos edáficos en donde se establecen los cultivos, en especial los perennes, en cuyo caso existen requerimientos mínimos de PE para el adecuado desarrollo de los árboles; se establecieron diferencias entre la biomasa acumulada, como consecuencia de ésta limitación. Al comparar el crecimiento de las plantas con la PE se evidenció que los individuos que crecieron en suelos con PE de 20 cm, presentaron un desarrollo relativamente semejante a plantaciones sin limitaciones de este tipo; mientras que, en suelos con PE inferior a 10 cm, la respuesta fue 3 a 5 veces menor.Abstract. It was evaluated the evolution of biomass, its differential distribution among the organs and some parameters of growth and development of acid lime (Citrus latifolia Tanaka, cv. Tahiti, grafted on Carrizo and Kryder patterns. The plants were established in soils with limitations by its effective depth (ED, which ranged between 10 and 20 cm. Assessments were effectuated at 24, 32 and 39 months after transplantation. It is must to keep in mind that root growth is conditioned to the soil attributes of the site where the crops are established, especially in the case of perennials, which have requirements of minimum PE in order to achieve an adequate development. Differences were established between biomass accumulated as a result of the limitation in effective depth. When comparing the growth of plants with ED, we found that the individuals that grew up in soils with

  14. Isla de calor en Toluca, México

    Directory of Open Access Journals (Sweden)

    Carlos Constantino Morales Méndez

    2007-01-01

    Full Text Available El clima de la ciudad de Toluca y del mundo ha sido modificado como consecuencia del crecimiento de su población y el aumento de las dimensiones de su distribución territorial. Las variaciones atmosféricas son más acusadas entre los espacios urbanos y rurales a medida que las ciudades son más grandes y su mancha urbana es más extensa,así como de la reducción de la vegetación, el aumento en la calefacción en casas y edificios y por la contaminación del aire. Para identificar los espacios con calor más intenso por la infraestructura urbana, se propone una metodología que consiste en la determinación de los valores de temperatura que se registraron en dos días típicos de invierno y verano, durante el día y la noche,mostrando la distribución de la isla de calor en la zona de estudio, a partir de los datos delas estaciones de la Red Automática de Monitoreo Ambiental (RAMA. Asimismo, se considera el comportamiento y variación de algunas variables atmosféricas como humedad relativa, precipitación y viento, para mostrar su comportamiento relativamente anómalo en la zona urbana.

  15. Diversidad de árboles y arbustos en fragmentos de bosque seco tropical en río Hato, Panamá

    Directory of Open Access Journals (Sweden)

    Omar R Lopez

    2015-01-01

    Full Text Available En fragmentos de bosque seco tropical en Río Hato, Panamá, estudiamos la composición florística según los árboles y arbustos. Establecimos 61 parcelas de 100 m2 distribuidas de forma aleatoria, totalizando 0.61 hectáreas. En cada unidad de muestreo medimos todos los individuos presentes con un DAP >5.0 cm. Encontramos un total de 52 especies de árboles representadas en veinticinco familias, de las cuales Fabaceae, Burseraceae, Myrtaceae y Rubiaceae aportan mayor número de especies (~35%. La especie Sloanea terniflora (Sessé & Moç. ex DC. Standl se encontró en más del 60.6% de los cuadrantes estudiados y resultó además ser la especie con mayor dominancia relativa (23%, seguida de Anacardium excelsum (Bertero & Balb. ex Kunth Skeels, que con solo quince individuos de grandes diámetros presentó una dominancia relativa del 10%. La diversidad promedio reveló índices intermedios (3.13 índice de Shannon. A pesar del bajo número de especies en comparación con otros BS-T de la región, los fragmentos en Río Hato conservan elementos florísticos de importancia ecológica y para la conservación de los bosques secos. Garcinia madruno (Kunth Hammel, una de las especies más abundante es clave en la producción de frutos para la fauna. Otras especies de importancia son Manilkara sapota (L. P. Royen y Copaifera aromatica Dwyer, las cuales aún son utilizadas como recurso maderero. Es prioritario para Panamá establecer estrategias de conservación que salvaguarden estos fragmentos como fuente de especies del bosque seco tropical y refugio para la vida silvestre.

  16. Oxytocin reduces caloric intake in men.

    Science.gov (United States)

    Lawson, Elizabeth A; Marengi, Dean A; DeSanti, Rebecca L; Holmes, Tara M; Schoenfeld, David A; Tolley, Christiane J

    2015-05-01

    Preclinical studies indicate that oxytocin is anorexigenic and has beneficial metabolic effects. Oxytocin effects on nutrition and metabolism in humans are not well defined. It was hypothesized that oxytocin would reduce caloric intake and appetite and alter levels of appetite-regulating hormones. Metabolic effects of oxytocin were also explored. A randomized, placebo-controlled crossover study of single-dose intranasal oxytocin (24 IU) in 25 fasting healthy men was performed. After oxytocin/placebo, subjects selected breakfast from a menu and were given double portions. Caloric content of food consumed was measured. Visual analog scales were used to assess appetite, and blood was drawn for appetite-regulating hormones, insulin, and glucose before and after oxytocin/placebo. Indirect calorimetry assessed resting energy expenditure (REE) and substrate utilization. Oxytocin reduced caloric intake with a preferential effect on fat intake and increased levels of the anorexigenic hormone cholecystokinin without affecting appetite or other appetite-regulating hormones. There was no effect of oxytocin on REE. Oxytocin resulted in a shift from carbohydrate to fat utilization and improved insulin sensitivity. Intranasal oxytocin reduces caloric intake and has beneficial metabolic effects in men without concerning side effects. The efficacy and safety of sustained oxytocin administration in the treatment of obesity warrants investigation. © 2014 The Obesity Society.

  17. Higher Unsaturation and Peroxidizability Indices in Caloric ...

    African Journals Online (AJOL)

    The biochemical processes involved in ageing are poorly understood. One of the general approaches to understanding the mechanism of ageing is to study the effect of experimental manipulations on life-span and the properties that are affected by them. Some of these experimental manipulations are caloric restriction and ...

  18. Epigenetic regulation of caloric restriction in aging

    Directory of Open Access Journals (Sweden)

    Daniel Michael

    2011-08-01

    Full Text Available Abstract The molecular mechanisms of aging are the subject of much research and have facilitated potential interventions to delay aging and aging-related degenerative diseases in humans. The aging process is frequently affected by environmental factors, and caloric restriction is by far the most effective and established environmental manipulation for extending lifespan in various animal models. However, the precise mechanisms by which caloric restriction affects lifespan are still not clear. Epigenetic mechanisms have recently been recognized as major contributors to nutrition-related longevity and aging control. Two primary epigenetic codes, DNA methylation and histone modification, are believed to dynamically influence chromatin structure, resulting in expression changes of relevant genes. In this review, we assess the current advances in epigenetic regulation in response to caloric restriction and how this affects cellular senescence, aging and potential extension of a healthy lifespan in humans. Enhanced understanding of the important role of epigenetics in the control of the aging process through caloric restriction may lead to clinical advances in the prevention and therapy of human aging-associated diseases.

  19. Coeficientes de transferencia de calor y pérdida de eficiencia en intercambiadores de calor de placas durante el enfriamiento del licor amoniacal

    Directory of Open Access Journals (Sweden)

    Enrique Torres-Tamayo

    2011-10-01

    Full Text Available En la planta de Recuperación de Amoniaco de la empresa niquelera Ernesto Che Guevara la pérdida de eficiencia del proceso de enfriamiento del licor amoniacal, mediante el uso de intercambiadores de calor de placas, se asocia a la incorrecta estimación de los coeficientes de transferencia de calor y la acumulación de incrustaciones en la superficie de intercambio; lo anterior incrementa el consumo de agua, la energía disponible en el sistema y los costos de mantenimiento. Se realizó una investigación en un intercambiador de calor de placas, con el objetivo de determinar los coeficientes de transferencia y la influencia de las incrustaciones en la pérdida de eficiencia de la instalación. Mediante un procedimiento iterativo se determinó la ecuación del número de Nusselt y su dependencia con el Reynolds y Prandtl, para ello se utilizó un diseño experimental multifactorial y mediciones de los parámetros de trabajo de la instalación en función del tiempo. Los resultados predicen el conocimiento de los coeficientes para el cálculo del número de Nusselt, con los valores de Reynolds y Prandtl, para ambos fluidos (licor amoniacal y agua. Los valores de los coeficientes del licor son inferiores, ello se debe a la presencia de componentes gaseosos. La comparación con resultados de otros autores muestra correspondencia con los de Thonon. Se recomienda la limpieza y mantenimiento de la instalación en un período de 27 días debido a la reducción de la eficiencia térmica hasta valores inferiores al 70 %.

  20. Diversidad de ácaros del orden prostigmata asociados al suelo de la Reserva Natural de Yotoco y del enclave seco del rio Dagua

    OpenAIRE

    Álvarez Ríos, Leonardo

    2012-01-01

    Las reservas naturales son lugares que albergan gran diversidad de flora y fauna, las cuales son protegidas por el hombre con fines de conservación. La Reserva Natural de Yotoco se encuentra ubicada en la vía que conduce de Buga a Loboguerrero entre los kilómetros 17 y 18 dentro del Departamento del Valle del Cauca y se caracteriza por ser un bosque húmedo premontano. Por su parte el enclave Seco del Río Dagua se encuentra ubicado al occidente de Colombia, sobre la vertiente oriental de la co...

  1. Análisis comparativo de la situación actual de los puertos secos en tres contextos diferentes: Colombia, México, España

    OpenAIRE

    Rozo Alvarado, Jonathan Efrain

    2013-01-01

    El presente trabajo tiene como finalidad analizar y comparar Puertos Secos en tres países diferentes: Colombia, México y España; y con ello determinar las claves o herramientas para el éxito de estos. Para esto, la investigación se llevó a cabo a nivel documental y teórico, abarcando desde documentos de investigación académicos y de entidades supranacionales, hasta documentos de carácter legislativo de diferente orden, para los tres países de estudio, incluyendo estudios privados y herramient...

  2. Estudios de bioprospección del coral blando Pseudopterogorgia elisabethae como fuente de sustancias con actividad biológica Fase IV

    OpenAIRE

    Correa Velandia, Hebelin

    2012-01-01

    Con el fin de ampliar el potencial de aplicación del octocoral Pseudopterogorgia elisabethae de la Isla de Providencia (Caribe Sur Occidental), se aislaron e identificaron nueve compuestos: las pseudopterosinas PsG, PsP, PsQ, PsS, PsT, PsU y 3-O-acetil- PsU y las seco-pseudopterosinas: seco-PsJ y seco-PsK, a los cuales junto con la mezcla en equilibrio de diterpenos no glicosidados (MEDNG aislada de P. elisabethae de la Isla de San Andrés) se les determinó un perfil citotóxico mas completo...

  3. Aplicação da Cadeia de Markov para Dias Secos e Chuvosos

    Directory of Open Access Journals (Sweden)

    André Luiz de Carvalho

    Full Text Available Resumo A precipitação é um fenômeno meteorológico importante na região Tropical, caracterizada por sua variabilidade espacial-temporal e eventos extremos associados. Assim, a informação prévia da ocorrência de um dia ser seco ou chuvoso é de extrema importância para diversas atividades humanas, em especial a agricultura. O objetivo desse trabalho foi analisar a ocorrência de dias secos e chuvosos na região de Rio Largo–Alagoas, por meio da Cadeia de Markov. Dados diários de precipitação entre 1973 e 2008 foram utilizados. Na definição de dias secos e chuvosos consideraram-se seis limites de precipitação e, aplicou-se a Cadeia de Markov, para identificar as probabilidades de ocorrências condicionais de dias secos e chuvosos. A região de estudo apresentou estações seca (setembro a março e chuvosa (abril a agosto melhor definidas, considerados valores limites de precipitação entre 0 e 2 mm. Maior ocorrência de dias secos e chuvosos ocorreu de novembro a dezembro (94% e junho a julho (84%, respectivamente. A Cadeia de Markov permitiu concluir que a transição entre dias secos e chuvosos é baixa ao longo do ano.

  4. Intake of calorically sweetened beverages and obesity

    DEFF Research Database (Denmark)

    Olsen, N J; Heitmann, B L

    2009-01-01

    The prevalence of obesity has increased in the past 30 years, and at the same time a steep increase in consumption of soft drinks has been seen. This paper reviews the literature for studies on associations between intake of calorically sweetened beverages and obesity, relative to adjustment...... for energy intake. Conclusions from previous reviews have been inconsistent, but some included many cross-sectional studies or studies supported by sugar industry. A literature search was performed for prospective and experimental studies using Medline and Scirus. Fourteen prospective and five experimental...... not find effects. Eight prospective studies adjusted for energy intake. Seven of these studies reported associations that were essentially similar before and after energy adjustment. In conclusion, a high intake of calorically sweetened beverages can be regarded as a determinant for obesity. However...

  5. Transferencia de calor a lechos empacados

    OpenAIRE

    Beltrán Feged, Alvaro; Bonilla Melendez, Alberto; Cancelado Arias, Miguel

    2012-01-01

    Consideremos el lecho de solidos granulados de la figura 1.El lecho esta a una temperatura u (z,t), y tiene un calor especifico  cs, que se toma constante. z es la altura del lecho, y t es el tiempo. A este lecho entran G unidades de masa de fluido por unidad de tiempo y de área de sección de lecho(1)(2)

  6. Transferencia molecular de calor, masa y/o cantidad de movimiento

    OpenAIRE

    Betancourt Grajales, Ramiro

    2008-01-01

    Este texto fue diseñado para proveer un tratamiento integrado de las tres áreas del transporte: impulso, calor y masa. Las similitudes entre las leyes de flujo permiten aplicar directamente analogías en el cálculo del transporte haciendo una economía en el esfuerzo docente–discente acorde con las pedagogías intensivas. Muchas de las ecuaciones básicas son matemáticamente idénticas cuando se expresan en términos de las variables y densidades de flujo generalizadas. El texto comienza con tra...

  7. Transferencia de calor en el secado solar a la intemperie de menas lateríticas ferroniquelíferas

    OpenAIRE

    Yoalbys Retirado-Mediaceja; Marbelis Lamorú-Urgelles; Ever Góngora-Leyva; Enrique Torres-Tamayo; Benigno Leyva-de la Cruz; Daynelis García-Batista

    2011-01-01

    En Moa, las menas lateríticas son sometidas a secado solar a la intemperie para reducirles el contenido de humedad antes de incorporarlas al proceso de secado térmico convencional. Este artículo evalúa los procesos de transferencia de calor fundamentales que tienen lugar durante el secado natural con el propósito de determinar el modo predominante de transferencia de calor. En dos pilas de menas lateríticas expuestas a secado solar natural se midieron las variables climatológicas y termodinám...

  8. SELECCIÓN DE “CABEZAS DE CLON” EN CAFÉ ROBUSTA (Coffea canephora EN EL TRÓPICO SECO, ECUADOR

    Directory of Open Access Journals (Sweden)

    Luis Alberto Duicela Guambi

    2016-06-01

    Full Text Available La investigación se ejecutó de junio 2007 a diciembre 2012, en el Centro Experimental de café robusta ubicado en el Recinto Las Mercedes, cantón Isidro Ayora, provincia del Guayas, donde prevalece la zona de vida “Bosque muy seco tropical”. El objetivo fue seleccionar árboles “Cabezas de clon” de alto valor genético para impulsar la caficultura en el trópico seco del litoral ecuatoriano. Se evaluaron 32 accesiones de distinto origen, cada una conformada de 20 cafetos. En una primera etapa, se evaluaron los caracteres morfológicos y productivos de las accesiones y en una segunda etapa se incluyeron los atributos organolépticos e industriales de los árboles promisorios. El análisis estadístico incluyó el cálculo de estadígrafos, análisis de varianza, componentes principales y conglomerados jerárquicos. Los resultados permitieron identificar y seleccionar dos accesiones tipo conilón y siete tipo robusta. Las “cabezas de clon” seleccionadas fueron: CONERB-01-Planta 13-14-17-20, CON-ETP-01-Planta 11, COF-01-Plantas 02 y 04, COF-02-Plantas 15 y 17, COF-04-Planta 18, COF-05-Planta 2, COF-06-Plantas 3-15-17, NP-4024-Planta 15 y NP-2024-Planta 10. El potencial productivo de los árboles seleccionados varía de 2,5 a 3,9 t ha-1, por tanto, se infiere que existen genotipos de alta productividad, adaptados al trópico seco y al manejo intensivo con riego.

  9. Estudio y optimización de los sistemas de intercambio de calor en generación termoeléctrica aplicada al aprovechamiento del calor residual

    OpenAIRE

    Aranguren Garacochea, Patricia

    2015-01-01

    La presente tesis doctoral estudia el aprovechamiento del calor residual mediante generación termoeléctrica para la obtención de potencia eléctrica generada gracias al efecto Seebeck. Dos son las aproximaciones empleadas, la simulación computacional, empleando variables obtenidas experimentalmente y la experimentación de escenarios reales. Ambas dos han obtenido valores muy prometedores para la generación eléctrica a través de los gases residuales. Con el desarrollo de esta tesis doctoral,...

  10. Use of non-caloric edulcorants in children

    OpenAIRE

    Calzada León Raúl; Altamirano Bustamante Nelly

    2014-01-01

    We analyze the health normativity for the denomination of non caloric edulcorants in Mexico, and the authorization for the use of natural and synthetic non caloric edulcorants in newborn and until puberty. Special emphasis was given to the consecutive points of safety required in order to assure that they are free of secondary effects. For each non caloric edulcorant available in Mexico, we looked into the studies which mention their side effects in terms of growth and overall.

  11. Use of non-caloric edulcorants in children

    Directory of Open Access Journals (Sweden)

    Calzada León Raúl

    2014-07-01

    Full Text Available We analyze the health normativity for the denomination of non caloric edulcorants in Mexico, and the authorization for the use of natural and synthetic non caloric edulcorants in newborn and until puberty. Special emphasis was given to the consecutive points of safety required in order to assure that they are free of secondary effects. For each non caloric edulcorant available in Mexico, we looked into the studies which mention their side effects in terms of growth and overall.

  12. Absorption heat pump integrated in an effluent purification system; Bomba de calor por absorcion integrada a un sistema de purificacion de efluentes

    Energy Technology Data Exchange (ETDEWEB)

    Santoyo, Socrates; Siqueiros, Javier; Heard, Christopher; Santoyo, Edgar [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1996-12-31

    The results derived of the integration of an absorption heat pump to an industrial effluents purification system, are presented. The advantages of these heat pumps with respect to heat pumps by mechanical compression of vapor, as well as the advantages in using absorption heat pumps in simple distillation systems, are mentioned. Finally, a description is made of the equipment designed and built, as well as the results obtained in a preliminary test. [Espanol] Se presentan los resultados derivados de la integracion de una bomba de calor por absorcion a un sistema de purificacion de efluentes industriales. Se mencionan las ventajas de este tipo de bombas de calor con respecto a las de calor por compresion mecanica de vapor, asi como las ventajas de usar bombas de calor en sistemas de destilacion simple. Finalmente, se describe el equipo disenado y construido, asi como los resultados obtenidos de una prueba preliminar.

  13. Diseño experimental, construcción y calibración de un sensor de flujo de calor para aplicaciones HVAC/R

    OpenAIRE

    Fonseca Díaz, Néstor; Burbano Jaramillo, Juan Carlos

    2007-01-01

    Este artículo presenta los resultados del estudio para el diseño experimental, construcción y calibración de un sensor de flujo de calor de utilidad en la detección de flujos de calor muy pequeños en Calefacción, Ventilación, Acondicionamiento de aire y Refrigeración (HVAC/R). Se propone el diseño de un sensor para medir flujos de calor en paredes de edificios y cuartos fríos del orden de 2 a 30 W/(m2K) con una incertidumbre total máxima de 5 % del flujo de calor medido. Actualmente, para ot...

  14. Modeling microscale heat transfer using Calore.

    Energy Technology Data Exchange (ETDEWEB)

    Gallis, Michail A.; Rader, Daniel John; Wong, Chung-Nin Channy; Bainbridge, Bruce L.; Torczynski, John Robert; Piekos, Edward Stanley

    2005-09-01

    Modeling microscale heat transfer with the computational-heat-transfer code Calore is discussed. Microscale heat transfer problems differ from their macroscopic counterparts in that conductive heat transfer in both solid and gaseous materials may have important noncontinuum effects. In a solid material, three noncontinuum effects are considered: ballistic transport of phonons across a thin film, scattering of phonons from surface roughness at a gas-solid interface, and scattering of phonons from grain boundaries within the solid material. These processes are modeled for polycrystalline silicon, and the thermal-conductivity values predicted by these models are compared to experimental data. In a gaseous material, two noncontinuum effects are considered: ballistic transport of gas molecules across a thin gap and accommodation of gas molecules to solid conditions when reflecting from a solid surface. These processes are modeled for arbitrary gases by allowing the gas and solid temperatures across a gas-solid interface to differ: a finite heat transfer coefficient (contact conductance) is imposed at the gas-solid interface so that the temperature difference is proportional to the normal heat flux. In this approach, the behavior of gas in the bulk is not changed from behavior observed under macroscopic conditions. These models are implemented in Calore as user subroutines. The user subroutines reside within Sandia's Source Forge server, where they undergo version control and regression testing and are available to analysts needing these capabilities. A Calore simulation is presented that exercises these models for a heated microbeam separated from an ambient-temperature substrate by a thin gas-filled gap. Failure to use the noncontinuum heat transfer models for the solid and the gas causes the maximum temperature of the microbeam to be significantly underpredicted.

  15. El contacto piel con piel : beneficios y limitaciones

    OpenAIRE

    Mateo Sota, Sonia

    2014-01-01

    El contacto precoz piel con piel tras el parto es una práctica beneficiosa tanto para el recién nacido como para los padres, contribuyendo al establecimiento del vínculo y la adaptación postnatal. El contacto piel con piel consiste en colocar al recién nacido boca abajo, desnudo, en contacto piel con piel sobre el abdomen o pecho de la madre durante los 120 minutos tras el nacimiento, taparle con una manta precalentada y cubrirle con un gorro seco. Es necesario la supervisión del recién nacid...

  16. A Dissociation between Recognition and Hedonic Value in Caloric and Non-caloric Carbonated Soft Drinks

    Directory of Open Access Journals (Sweden)

    Franco eDelogu

    2016-01-01

    Full Text Available Consumption of sugar-sweetened beverages (SSBs is considered to be a contributor to diabetes and the epidemic of obesity in many countries. The popularity of non-caloric carbonated soft drinks as an alternative to SSBs may be a factor in reducing the health risks associated with SSBs consumption. This study focuses on the perceptual discrimination of SSBs from artificially sweetened beverages (ASBs. 55 college students rated 14 commercially available carbonated soft drinks in terms of sweetness and likeability. They were also asked to recognize if the drinks contained sugar or a non-caloric artificial sweetener. Overall, participants showed poor accuracy in discriminating drinks’ sweeteners, with significantly lower accuracy for SSBs than ASBs. Interestingly, we found a dissociation between sweetener recognition and drink pleasantness. In fact, in spite of a chance-level discrimination accuracy of SSBs, their taste was systematically preferred to the taste of non-caloric beverages. Our findings support the idea that hedonic value of carbonated soft drinks is dissociable from its identification and that the activation of the pleasure system seems not to require explicit recognition of the sweetener contained in the soft drink. We hypothesize that preference for carbonated soft drinks containing sugar over non-caloric alternatives might be modulated by metabolic factors that are independent from conscious and rational consumers’ choices.

  17. Caloric versus low-caloric sweeteners: Can the body be fooled?

    NARCIS (Netherlands)

    Smeets, P.A.M.

    2010-01-01

    Low-caloric artificial sweeteners have been around for several decades now. Still, the debate over their usefulness in decreasing energy intake is ongoing. In principle, replacing sugar-containing foods with 'light' versions will lead to decreased energy intake. However, the reality of food intake

  18. Temperatura y rangos de confort térmico en viviendas de bajo costo en clima árido seco

    Directory of Open Access Journals (Sweden)

    Luis Herrera Sosa

    2015-03-01

    Full Text Available Este documento presenta los resultados de un estudio de campo para determinar la temperatura de confort de habitantes de viviendas de bajo costo en dos ciudades de clima cálido-seco al norte de México: Chihuahua (28º LN, 106º LO y Ciudad Juárez (31ºLN, 106ºLO. El estudio de campo se realizó con el enfoque adaptativo de confort térmico y de acuerdo con los requerimientos de la ISO 10551. El estudio fue aplicado a 531 habitantes de viviendas construidas por el Instituto de Vivienda de Chihuahua, durante dos periodos: temporada de invierno (febrero y temporada de verano (julio. Como el clima de la región tiene características de climas "asimétricos", llamado así por Nicol (1993, los datos obtenidos en el estudio de campo se analizaron mediante el Método Intervalos de los Promedios de Sensación Térmica (IPST (Gómez-Azpeitia, et. al, 2009. La investigación tiene como objetivos evaluar este tipo de viviendas que ofrece el gobierno local y proponer recomendaciones para el diseño de nuevas viviendas.

  19. Nutrigenetics and nutrigenomics of caloric restriction.

    Science.gov (United States)

    Abete, Itziar; Navas-Carretero, Santiago; Marti, Amelia; Martinez, J Alfredo

    2012-01-01

    Obesity is a complex disease resulting from a chronic and long-term positive energy balance in which both genetic and environmental factors are involved. Weight-reduction methods are mainly focused on dietary changes and increased physical activity. However, responses to nutritional intervention programs show a wide range of interindividual variation, which is importantly influenced by genetic determinants. In this sense, subjects carrying several obesity-related single-nucleotide polymorphisms (SNPs) show differences in the response to calorie-restriction programs. Furthermore, there is evidence indicating that dietary components not only fuel the body but also participate in the modulation of gene expression. Thus, the expression pattern and nutritional regulation of several obesity-related genes have been studied, as well as those that are differentially expressed by caloric restriction. The responses to caloric restriction linked to the presence of SNPs in obesity-related genes are reviewed in this chapter. Also, the influence of energy restriction on gene expression pattern in different tissues is addressed. Copyright © 2012 Elsevier Inc. All rights reserved.

  20. Caloric testing by continuous automatic alternating irrigation.

    Science.gov (United States)

    Reker, U

    1980-01-01

    Quantitative caloric test results show a high variability. They were described as questionable by Frenzel (1955) and a review of the test was recommended by Hood (1973). Thus, we developed a new method: continuous automatic alternating irrigation. An irrigator is connected to two water-baths of 30 degrees C and 44 degrees C. A time-relays switches over from one bath to the other every 60 s. The continuous, but alternating, irrigations produce subsequently alternating exponential temperature waves in the temporal bone. The mathematical model shows a quasi-periodicity and sufficient symmetry of the alternating thermal gradient across the canal, except for the first stimulus. After 11 irrigations of 60 s, a short (20 s) "washout" irrigation terminates the sequence. By the five repetitions of each stimulus and the additional possibility of correlating the response to the paper-marked stimulus periodicity the judgement is far more reliable and therefore, in doubtful cases, despite the five-fold data, quicker. The technical device is simple enough for routine use and inexpensive. The results of the caloric test are now much more clear-cut and the correlation to a known clinical pathology is remarkably high.

  1. Transferencia de calor durante la congelación, el almacenamiento y la descongelación de alimentos

    OpenAIRE

    Salvadori, Viviana Olga

    1994-01-01

    En el presente trabajo se estudian distintos aspectos relacionados con la congelación y el almacenamiento de productos congelados, con los siguientes objetivos: - Optimizar el diseño de sistemas para la congelación o almacenamiento de alimentos a través de un mejor conocimiento de los fenómenos de transferencia de calor que tienen lugar en los mismos. Esto involucra un adecuado dimensionamiento de los equipos con el consiguiente ahorro en los costos de inversión. - Desar...

  2. The reno-protective effects of dietary caloric restriction against ...

    African Journals Online (AJOL)

    This study has demonstrated that these pathophysiological alterations caused by disturbed glucose homeostasis are reversed by caloric restriction and thus CR may have therapeutic/preventive potential towards the development of diabetic nephropathy. Keywords: dietary caloric restriction; lipid peroxidation; oxidative ...

  3. Estimación del agua corporal total y del peso seco, usando impedancia bioeléctrica tetrapolar de multifrecuencia (BIA-4 en pacientes en hemodiálisis

    Directory of Open Access Journals (Sweden)

    Doris Ramírez de Peña

    2015-01-01

    Full Text Available Antecedentes. La medición del "peso seco" en pacientes renales se ha tornado difícil por el sinnúmero de variables que en él intervienen, dada la importancia de conocerlo por cuanto con él se determina el tratamiento diálitico, farmacólogico y nutricional se ha trabajado en diferentes ecuaciones y métodos para obtenerlo. Objetivo. Describir la composición corporal, el agua corporal total y el peso seco de pacientes con enfermedad renal en Hemodiálisis Materiales y Métodos. Se realizó un estudio descriptivo transversal en seis fases, desde el año 2001 al 2010. Con el método de BIA-1 Y BIA-4 (bioimpedancia de unifrecuencia y tetrapolar y la ecuación Ramírez-Almanza. Para la determinación del peso seco se utilizaron los valores de normovolemia e hipervolemia y se utilizó un nuevo instrumento para diagnóstico nutricional VGS-MIS. Resultados. El 50% de los pacientes estudiados tenían un diagnóstico de Diabetes e Hipertensión, el 87% con riesgo leve de desnutrición, solo el 3% sin riesgo de desnutrición. El punto de cohorte de la Resistencia dada por la bioimpedancia de 550 permite determinar que pacientes con valores por debajo de éste son sintomáticos con una alta sensibilidad 73% y una especificidad de 50%. Para el agua total corporal es posible utilizar la ecuación Ramirez-Almanza pues tiene una buena correlacion mediana (0.76con el índice de impedancia de Kushner. La VGS-MIS es el mejor método de valoración encontrada hasta ahora para paciente renal porque involucra diferentes parámetros físicos, nutricionales, clìnicos y bioquímicos. Conclusión. El uso de la Bioimpedancia en paciente en hemodiálisis ha permitido una mayor exactitud en el cálculo del agua corporal total, peso seco y estado nutricional de los pacientes en hemodiálisis.

  4. Transferencia de calor en el secado solar a la intemperie de menas lateríticas ferroniquelíferas

    Directory of Open Access Journals (Sweden)

    Yoalbys Retirado-Mediaceja

    2011-03-01

    Full Text Available En Moa, las menas lateríticas son sometidas a secado solar a la intemperie para reducirles el contenido de humedad antes de incorporarlas al proceso de secado térmico convencional. Este artículo evalúa los procesos de transferencia de calor fundamentales que tienen lugar durante el secado natural con el propósito de determinar el modo predominante de transferencia de calor. En dos pilas de menas lateríticas expuestas a secado solar natural se midieron las variables climatológicas y termodinámicas que influyen en la transferencia de calor por convección y radiación durante el secado y se calcularon, además, los criterios adimensionales para determinar el tipo predominante de convección. Se comprobó que durante el secado solar a la intemperie predomina la convección y que en las condiciones de experimentación analizadas la radiación tuvo una incidencia secundaria. Los resultados evidenciaron que el calor se transfiere por convección libre, forzada y mixta, predominando la forzada, para la cual los coeficientes de transferencia de calor mínimos y máximos mostraron pequeñas variaciones entre ambas pilas. Los flujos de calor por convección promedios fueron 978,74 y 1 156,58 W/m2 , mientras que los flujos por radiación ascendieron a 324,71 y 355,36 W/m2 para las pilas #1 y #2, respectivamente.

  5. Diseño de una máquina de rotomoldeo sin aporte de calor

    OpenAIRE

    Montes Cale, Pablo

    2016-01-01

    El presente proyecto consiste en el diseño de una máquina de rotomoldeo sin aporte de calor con la que se puedan generar piezas huecas de plástico de resina autocurable detallando los tipos de estas resinas utilizadas en este sistema al principio. La máquina está construida mediante un sistema modular para facilitar la reparación o el cambio de piezas ante posible rotura. El movimiento de la máquina está gobernado mediante un variador de frecuencia acoplado a un motorreducto...

  6. Coeficientes de transferencia de calor en enfriadores de mineral laterítico a escala piloto

    OpenAIRE

    Ángel Legrá-Legrá; Yudmila Spencer-Rodríguez; Yoalbys Retirado-Mediaceja; Ángel O. Columbié-Navarro; Marbelis Lamorú-Urgellés; Ever Góngora-Leyva

    2009-01-01

    En la Planta de Hornos de Reducción de la empresa niquelera Ernesto Guevara las elevadas temperaturas del mineral reducido a la salida de los enfriadores (coolers) afectan el desarrollo eficiente del proceso de lixiviación. Se realizó una investigación, a escala piloto, en los enfriadores de mineral reducido con el fin de evaluar el comportamiento de los parámetros de transferencia de calor que caracterizan el proceso; para ello se registraron los valores de temperatura del agua y del flujo y...

  7. Efecto del calor aportado en recargues nanoestructurados base hierro

    Directory of Open Access Journals (Sweden)

    Agustín Gualco

    2013-12-01

    Full Text Available En los últimos años se han desarrollado consumibles de soldadura que depositan recubrimientos duros de aleaciones base hierro nanoestructuradas de gran resistencia al desgaste abrasivo. Las resistencias al desgaste erosivo y abrasivo están controladas principalmente por la composición química y la microestructura. A su vez, la microestructura del metal depositado puede presentar variaciones con el procedimiento de soldadura empleado, especialmente en relación al aporte térmico. Los parámetros operativos que definen el aporte térmico (tensión, corriente y velocidad de soldadura afectan aspectos como la geometría del cordón (ancho, penetración y sobremonta y la dilución con el material base. El propósito de este trabajo fue estudiar el efecto del calor aportado sobre las características geométricas del cordón, la dilución y la evolución microestructural de una aleación nanoestructurada base hierro, depositada por FCAW. Se soldaron muestras con aportes térmicos de entre 0,5 y 3,5 kJ/mm. Sobre cada cupón soldado se realizó un relevamiento dimensional, se analizó la composición química y se caracterizó la microestructura usando microscopías óptica y electrónica de barrido y difracción de rayos X. También se midieron la microdureza del depósito, el tamaño de cristalita y el grado de dilución. Se observó una gran influencia de las condiciones de proceso sobre la geometría del cordón. La dilución varió entre un 30 y un 40%, la microdureza del depósito se encontró entre 800 y 870 HV1 y el tamaño de cristalita osciló entre 105 y 130 nm, en función de las variables de proceso empleadas. Las mayores durezas y los menores tamaños de cristalita se obtuvieron con el menor aporte térmico, asociado a una menor dilución.

  8. Heat pump for purification of geothermal brines; Bomba de calor para purificacion de salmuera geotermica

    Energy Technology Data Exchange (ETDEWEB)

    Santoyo-Gutierrez, S; Barragan-Reyes, R.M; Holland, F.A [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)]. E-mail: rmb@iie.org.mx

    2007-01-15

    Integrated use of geothermal resources is one of the most important goals for the future. Presently geothermal heat pumps offer two benefits: using heat from residual brines and converting these brines into very pure water. Designs and descriptions are presented of an experimental system to purify geothermal brines integrated to an adsorption heat-pump. The system was constructed and tested in the IIE (Institute for Electrical Research) facilities. During the experimental stage, pure water was obtained. Maximum capacity for pure water was 4.3 kg per hour, presenting an Actual Coefficient of Performance (COP)A of 1.4. The results are encouraging to project units at an industrial level for operating with geothermal and/or solar heat. [Spanish] El aprovechamiento integral de los recursos geotermicos en todas sus formas es una de las metas importantes a lograr en los proximos anos. Hoy en dia, el uso de las bombas de calor en la geotermia ofrece un doble beneficio: aprovechan el calor de los fluidos de desecho y tienen la capacidad de transformar la salmuera geotermica en agua de alta pureza. Se presenta el diseno y descripcion de un sistema experimental para purificacion de salmuera geotermica integrado a una bomba de calor por absorcion, el cual fue construido y probado en el Instituto de Investigaciones Electricas. En toda la etapa de experimentacion se obtuvo agua pura. La capacidad maxima alcanzada de produccion de agua pura de este sistema fue de 4.3 kg por hora, mostrando un rendimiento en terminos del Coeficiente Real de Rendimiento (COP)A de 1.4. Estos resultados se consideran alentadores para la proyeccion de unidades a escala industrial que puedan ser operadas con calor geotermico y/o solar.

  9. ESTRUCTURA POBLACIONAL Y ETOLOGÍA DE Bradypus variegatus EN FRAGMENTO DE BOSQUE SECO TROPICAL, CÓRDOBA - COLOMBIA

    Directory of Open Access Journals (Sweden)

    Jesús Ballesteros C, M.Sc

    2009-12-01

    Full Text Available Objetivo. Contribuir al conocimiento de la composición poblacional y etología del oso perezoso (Bradypus variegatus en la reserva natural viento solar, un fragmento de bosque seco tropical (bs-T del municipio de Moñitos, departamento de Córdoba. Materiales y métodos. Durante octubre 2004 a mayo 2005, se realizaron conteos directos con observación visual en el sendero principal de la reserva, haciendo transectos de un kilómetro de largo x 100 m de ancho. Se registró el número de animales observados, hábitos alimenticios, estructura poblacional según sexo mediante marcado natural. Se realizaron observaciones sobre comportamiento animal y actividades de desplazamiento diurno, con anotaciones sobre su ecología, y aspectos importantes para la conservación. Resultados. En enero del 2005 se registraron 70 individuos, con una composición de 31% machos, 53% hembras y 16% crías. Durante la época seca del año, (enero-abril la mayoría de la vegetación arbórea es caducifolia, disminuyendo en forma importante el follaje de los árboles, lo cual facilitó el conteo de la población. La vegetación de bs-T está dominada por Pseudobombax septenatum, cuyo follaje es muy apetecido por el oso perezoso. Conclusiones. Los datos indican que la composición poblacional del oso perezoso en la reserva natural viento solar, está conformada principalmente por individuos adultos, encontrándose una baja proporción de crías; lo que podría estar reflejando problemas de crecimiento poblacional por efecto de baja disponibilidad y baja calidad del hábitat.

  10. Estudio de la influencia del número de módulos termoeléctricos en la potencia calorífica disipada por un sistema de auto-refrigeración termoeléctrica

    OpenAIRE

    Conde Olazábal, Igor

    2014-01-01

    En el desarrollo del presente trabajo de fin de grado se expone un estudio sobre una de las múltiples aplicaciones de aprovechamiento de calor residual mediante termoelectricidad. Se trata de una aplicación novedosa y de creciente interés conocida por el nombre de “autorrefrigeración termoeléctrica” (ARTE). Dado un dispositivo cualquiera que genera calor, bien puedan ser transistores IGBT para el caso de electrónica de potencia o cualquier otra aplicación con generación de calor en el proceso...

  11. Analysis of caloric test responses in sudden hearing loss.

    Science.gov (United States)

    Shih, Cheng-Ping; Chou, Yu-Ching; Chen, Hsin-Chien; Lee, Jih-Chin; Chu, Yueng-Hsiang; Wang, Chih-Hung

    2017-02-01

    Sudden sensorineural hearing loss is characterized by a rapid-onset hearing loss that develops within 3 days. Vertigo may also be present. We conducted a retrospective study to investigate whether the severity of a loss of caloric function is associated with the initial hearing loss and with hearing recovery. Our study population was made up of 135 patients-67 men and 68 women, aged 25 to 71 years (mean: 50.9)-with sudden sensorineural hearing loss who had undergone bithermal caloric testing. We compared various patient factors according to patients' hearing level and their response to caloric testing. We also analyzed the canal paresis (CP) value in patients with an abnormal caloric response according to three factors: disease severity, vertigo, and hearing recovery, and we evaluated the correlation between the loss of caloric function and hearing outcomes. We found that an abnormal caloric response was significantly associated with a profound hearing loss at presentation, the presence of vertigo, and poor hearing recovery. Among patients with an abnormal caloric response, the CP value was significantly correlated with hearing recovery (r = 0.503, p = 0.001). Poor hearing recovery was seen in 80% of patients with a CP value of ≥40% but in only 25% of patients with a value of hearing recovery was worse in the patients with a CP value of ≥40% (p = 0.002). We conclude that a CP value of ≥40% is a significant prognostic factor for an unfavorable treatment outcome.

  12. AVIFAUNA DEL BOSQUE SECO TROPICAL EN EL DEPARTAMENTO DEL TOLIMA (COLOMBIA: ANÁLISIS DE LA COMUNIDAD

    Directory of Open Access Journals (Sweden)

    Lozada Sergio

    2011-06-01

    Full Text Available RESUMENLa zona de vida Bosque Seco Tropical (bs-T en el Alto Valle del Magdalena (AVM,departamentos del Tolima, Cundinamarca y Huila, no cuenta con información detalladasobre el estado de su avifauna, por lo que se requieren estudios que profundicen yllenen este vacío. Nuestro objetivo fue analizar la comunidad de aves del bs-T en 37localidades del departamento del Tolima, Colombia, a través de revisiones de artículospublicados, documentos técnicos y listados de expertos no publicados. Registramos297 especies de aves y la tasa de registro de especies fue considerada como unavariable independiente que permitió comparaciones entre localidades con diferentesesfuerzos de muestreo; así, las localidades San Pablo y Corinto, con valores altospara esta variable, se convierten en localidades importantes para la conservación. Lalocalidad con el mayor número de especies registradas (162 fue la Laguna El Toro,probablemente porque se han realizado más estudios en dicha localidad. Las especiesen las categorías ecológicas II (de amplia tolerancia y III (de áreas abiertas registraronel mayor número de especies, 126 y 91 respectivamente; mientras que en la categoríaecológica I (especies asociadas bosque solo se registraron 35 especies. Con baseen curvas de rarefacción y el modelo de Clench estimamos entre el 92-93% de lasespecies esperadas para la región (ca. 322. Nosotros concluimos que el alto númerode especies de aves registradas en el bs-T del Tolima, se encuentra en las categoríasecológicas II y III, y estaría relacionada con la heterogeneidad vegetal y las diferentesunidades de paisaje en la región. Adicionalmente, el número de especies del bs-T en eldepartamento del Tolima supera los registros para la costa norte colombiana, y paísescomo Nicaragua, Costa Rica y México, en esa misma zona de vida.

  13. Enfriamiento de café pergamino seco a granel utilizando aireación mecánica controlada

    Directory of Open Access Journals (Sweden)

    Julio E. Ospina M.

    2011-01-01

    Full Text Available Con el fin de garantizar que el café almacenado a granel conserve su calidad durante el tiempo necesario de almacenamiento, se estudió el enfriamiento del café pergamino seco en silos experimentales de dimensiones: 0.5m x 0.5m y 2.8 m de altura, utilizando aire enfriado mecánicamente. Los rangos estudiados fueron: temperatura de 10 a 220C humedad relativa de 66 a 98%y contenido de humedad del grano de 8 a 13.57% b.h. Durante la etapa de almacenamiento se evaluó la variación de la calidad del café según los criterios de coloración de la almendra, población de microorganismos y prueba de taza; paralelamente se dejaron muestras almacenadas en sacosa las condiciones de Chinchiná, como muestra testigo buscando determinar la bondad del almacenamiento a granel, también se dejó un silo sin aireación para determinar el efecto de la aireación controlada en la calidad del café.

  14. [Caloric restriction: about its positive metabolic effects and cellular impact].

    Science.gov (United States)

    Ortiz-Bautista, Raúl Julián; Aguilar-Salinas, Carlos Alberto; Monroy-Guzmán, Adriana

    2013-01-01

    Caloric restriction, as a 30 to 60% decrease of ad libitum balanced caloric intake, without malnutrition, is the non-genetic strategy that has consistently extended the average and maximum lifespan of most living beings, and it has been tested from unicellular organisms like yeast Saccharomyces cerevisiae to Rhesus primates. In addition, various genetic and pharmacological caloric restriction models have shown to protect against cancer, cardiovascular and neurodegenerative diseases. Primate studies suggest that this intervention delays the onset of age-related diseases; in humans, it has physiological, biochemical and metabolic effects decreasing diabetes and cardiovascular disease risk factor. Although currently the mechanism by which caloric restriction has its positive effects at the cellular level is unknown, it has been reported to decrease oxidative stress and increase in mitochondrial biogenesis.

  15. Fenología de árbol Sideroxylon capiri (Sapotaceae en el Bosque Seco Tropical de Costa Rica

    Directory of Open Access Journals (Sweden)

    Elmer G García

    2005-06-01

    Full Text Available Se estudió la fenología del árbol de tempisque Sideroxylon capiri (A.DC. Pittier en el Bosque Seco Tropical del Parque Nacional Barra Honda (Costa Rica, desde marzo de 1996 hasta febrero de 2000. Para ello se tomaron diez árboles escogidos al azar, a los cuales se les evaluó la fenología, una vez al mes durante los dos primeros años y posteriormente cada dos meses. Además, se tomaron datos climatológicos in situ para establecer relaciones con el comportamiento fenológico. Se encontró que los árboles renuevan el follaje cada año, pero la caída ocurre durante el período lluvioso o a inicios del seco, por lo que, contrario a lo que sucede en otras especies nativas de este tipo de bosque, el déficit hídrico del suelo no es el responsable de la caída del follaje, sino que deben haber otros factores ambientales responsables de ello. Entre estos podrían estar el fotoperíodo y la presencia de herbívoros. Durante los meses más secos (marzo y abriltodos los árboles mantienen su follaje al máximo y para que esto ocurra deben existir también mecanismos fisiológicos particulares. Respecto a los procesos de floración y fructificación, estos se presentan todos los años, especialmente en el período de sequía, pero es posible que ocurran en cualquier otra época del año. Existen diferencias en la magnitud de la floración y fructificación, dependiendo de la época y del individuo. Se discuten las posibles causas de este comportamiento fenológico, así como las ventajas ecológicas que podría tenerPhenology of the tree Sideroxylon capiri (Sapotaceae at the tropical dry forest in Costa Rica. From March 1996 until February 2000, an study about the phenology of the Tempisque tree [Sideroxylon capiri (A.DC. Pittier ] was made in the Tropical Dry Forest of the Barra Honda National Park (Costa Rica.Ten trees were choosen at random and their phenology was evaluated monthly during the first two years and every two months afterwards

  16. Characteristics of non caloric dulcorants and their use in children

    OpenAIRE

    Calzada León Raúl; Altamirano Bustamante Nelly

    2014-01-01

    This is a descriptive review of the elaboration routes, the physical and chemical characteristics, metabolism and clearance, sweetener level, residual flavor, maximal recommended ingestion, security levels and the assessment of growth and development problems in children (from newborns, including prematures, to the end of puberty), of the main no caloric edulcorants used in Mexico. The no caloric edulcorants included in this review are: aspartame, acesulfame-K, sucralose, sacarin, ciclamates,...

  17. Characteristics of non caloric dulcorants and their use in children

    Directory of Open Access Journals (Sweden)

    Calzada León Raúl

    2014-07-01

    Full Text Available This is a descriptive review of the elaboration routes, the physical and chemical characteristics, metabolism and clearance, sweetener level, residual flavor, maximal recommended ingestion, security levels and the assessment of growth and development problems in children (from newborns, including prematures, to the end of puberty, of the main no caloric edulcorants used in Mexico. The no caloric edulcorants included in this review are: aspartame, acesulfame-K, sucralose, sacarin, ciclamates, thaumatin, D- tagatose, estevia and alitame.

  18. Adaptación de las TIC al Laboratorio de Transferencia de Calor en el Instituto Minas Fredonia

    OpenAIRE

    Pérez Montes, Ricardo Adolfo

    2014-01-01

    Resumen: Se implementó el laboratorio de Transferencia de Calor con cinco puestos de trabajo computarizado. Cada uno está constituido por un sistema de adquisición utilizando la tarjeta Arduino y sensores de temperatura, sobre el sistema operativo Windows 8. Se probó con una Unidad de Enseñanza Potencialmente Significativa-UEPS para los grados Noveno, décimo y once en la Institución Educativa de Minas Fredonia, institución de media técnica agropecuaria. Para comparar las bondades en la enseña...

  19. La ola de calor de 2003 en España, entre la realidad biofísica y el reconocimiento mediático

    OpenAIRE

    Fernández Reyes, Rogelio

    2012-01-01

    Globalización Media permite medios de comunicación para cubrir desastres naturales en una forma mucho más eficaz. Hoy, muchos de esos desastres están relacionados con el cambio climático. Sin embargo, en agosto de 2003, mientras que la ola de calor se estaba produciendo en España apenas existen voces conectadas al cambio climático. Algunos científicos argumentan que no podemos afirmar la ola de calor en 2003 fue causado por el cambio climático. Pero también hay investigaciones y referencias q...

  20. Estudio sobre los efectos de campo acústico en la transmisión de calor de un calentador de aire de admisión

    OpenAIRE

    RAMÍREZ CARDONA, MARÍA ISABEL

    2015-01-01

    Se ha documentado que la presencia de ondas acústicas puede influir sobre la transferencia de calor, a través de las modificaciones producidas por las ondas en la capa límite. Esta opción presenta a priori ventajas sobre otras formas de mejora de la transferencia de calor, como la corrugación de superficies, ya que su influencia sobre la pérdida de carga es menor y el requerimiento energético es marginal comparado con el del calentador mismo. Se pretende por ello estudiar el potencial de mejo...

  1. Role of caloric homeostasis and reward in alcohol intake in Syrian golden hamsters

    OpenAIRE

    Gulick, Danielle; Green, Alan I.

    2010-01-01

    The Syrian golden hamster drinks alcohol readily, but only achieves moderate blood alcohol levels, and does not go through withdrawal from alcohol. Because the hamster is a model of caloric homeostasis, both caloric content and reward value may contribute to the hamster’s alcohol consumption. The current study examines alcohol consumption in the hamster when a caloric or non-caloric sweet solution is concurrently available and caloric intake in the hamster before, during, and after exposure t...

  2. Síndrome seco - Síndrome de Sjögren

    OpenAIRE

    Cañas Dávila, Carlos Alberto

    2002-01-01

    ¿Qué es el "síndrome seco"?/ ¿Qué es el síndrome Sjögren?/ ¿Qué es un síndrome de Sjögren primario y qué es un síndrome de Sjögren secundario?/ ¿Cuáles son las causas del síndrome de Sjögren?/ ¿Qué otras manifestaciones distintas a los síntomas secos puede ocasionar el síndrome de Sjögren?/ ¿Cómo se diagnostica un síndrome de Sjögren?/ ¿Cuál es el tratamiento del síndrome de Sjögren?/ ¿Qué tan frecuente es el síndrome de Sjögren?

  3. Sistemas de transmisión de calor para hornos de vía seca en la fabricación de cemento

    Directory of Open Access Journals (Sweden)

    Tonry, J. Richard

    1961-12-01

    Full Text Available Not availableEn los últimos años se han puesto en marcha numerosos sistemas para mejorar la transmisión de calor en los hornos de vía seca y, en consecuencia, el consumo de combustible en la industria del cemento. El objetivo principal ha sido el ahorro de combustible y la obtención de mayores velocidades de producción en comparación con los hornos horizontales normales. Estos sistemas pueden dividirse en dos grupos: (1 externos, donde fluyen en contracorriente sólidos y gases calientes, 71 (2 internos, con exposición de superficie y radiación de la misma como medio de transmisión de calor. Esta tendencia a sistemas de este tipo puede compararse a la que hubo hace cuarenta años con las calderas de recuperación de calor en hornos de vía seca. El primer objetivo, tanto entonces como ahora, es la mejor utilización del calor en los gases de escape.

  4. Use of caloric and non-caloric sweeteners in US consumer packaged foods, 2005–9

    Science.gov (United States)

    Ng, Shu Wen; Slining, Meghan M.; Popkin, Barry M.

    2012-01-01

    Our understanding of the use of caloric (CS) and non-caloric sweeteners (NCS) in the US food supply is limited. This study utilizes full ingredient list and nutrition facts panel (NFP) data from Gladson Nutrition Database, and nationally representative purchases of consumer packaged foods from Nielsen Homescan in 2005 through 2009 to understand the use of CS (including FJC) and NCS in CPG foods. Of the 85,451 uniquely formulated foods purchased during 2005–2009, 75% contain sweeteners (68% with CS only, 1% with NCS only, 6% with both CS and NCS). CS are in >95% of cakes/cookies/pies, granola/protein/energy bars, ready-to-eat cereals, sweet snacks, and sugar-sweetened beverages. NCS are in >33% of yogurts and sports/energy drinks, 42% of waters (plain or flavored), and most diet sweetened beverages. Across unique products, corn syrup is the most commonly listed sweetener, followed by sorghum, cane sugar, high fructose corn syrup and FJC. Also, 77% of all calories purchased in the US in 2005–2009 contained CS and 3% contained NCS, while 73% of the volume of foods purchased contained CS and 15% contained NCS. Trends during this period suggest a shift towards the purchase of NCS-containing products.Our study poses a challenge toward monitoring sweetener consumption in the US by discussing the need and options available to improve measures of CS and NCS, and additional requirements on NFPs on CPG foods. PMID:23102182

  5. Análisis temporal y control químico de antracnosis (Colletotrichum gloeosporioides Penz.) y cenicilla (Oidium mangiferae Berthet) en mango (Mangifera indica) cv. Haden en el trópico seco de Guerrero, México.

    OpenAIRE

    Pérez Rodríguez, Amado

    2012-01-01

    Se estudió el desarrollo temporal de epidemias de antracnosis y cenicilla en el huerto experimental de mango Zozontla1 en Arcelia (trópico seco), Guerrero, México; sujetos a un programa de fungicidas que consideró distintos ingredientes activos, así como su combinación y secuencias de aplicación durante el ciclo 2010-11. Los estados fenológicos más susceptibles fueron floración plena (30%), amarre de frutos (3-5 mm Ø) (35%) y frutos de 8-15 mm Ø (35%). El control se obtuvo al iniciar con ingr...

  6. A new bis-seco-abietane diterpenoid from Hyptis crenata Pohl ex Benth.

    Science.gov (United States)

    Yun, Young Sook; Fukaya, Haruhiko; Nakane, Takahisa; Takano, Akihito; Takahashi, Shigeru; Takahashi, Yuji; Inoue, Hideshi

    2014-12-05

    A new, highly oxidized, bis-seco-abietane diterpenoid named hyptisolide A (1) was isolated from Hyptis crenata Pohl ex Benth. Its structure and stereochemistry were elucidated on the basis of data obtained by HRESIMS, NMR, and X-ray diffraction analyses, and its absolute configuration was determined with vibrational circular dichroism spectroscopy. By reporter gene assay, 1 was demonstrated to induce cAMP-responsive element-dependent transcription in Neuro2A cells.

  7. Islas de calor urbano en Tampico, México. Impacto del microclima a la calidad del hábitat

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Fuentes Pérez

    2014-01-01

    Full Text Available De todas las modificaciones climáticas por causa urbana, las térmicas son las más conocidas por los propios ciudadanos. La acción transformadora del espacio natural sobre el que se realiza el emplazamiento de la ciudad, llega a ser productora en gran medida de sus condiciones ambientales, incluida la climatología urbana. Todo proceso de urbanización sustituye los suelos y áreas naturales por superficies construidas, cuyos materiales se caracterizan por una baja reflectividad, con disminución de la capacidad de absorción de agua y un comportamiento térmico propicio para el almacenamiento y la emisión de calor. Estos elementos coadyuvan a realzar la temperatura atmosférica de la ciudad en relación con su entorno menos urbanizado a través de un fenómeno conocido como efecto de islas de calor urbano, produciendo un impacto del microclima a la calidad del hábitat. La presente investigación experimental aplicada tiene como objetivo, demostrar la metodología de investigación adoptada, para realizar las islas de calor urbanas en Tampico, México.

  8. Automobilismo: no calor da competição Automovilismo: en el calor de la competición Car racing: in the heat of competition

    Directory of Open Access Journals (Sweden)

    Luiz Oswaldo Carneiro Rodrigues

    2004-06-01

    ções ambientais do autódromo no dia de sua morte.El presente artículo cuestiona el papel del calor como un factor de riesgo adicional para el accidente que sufrió Ayrton Senna. El automovilismo de competición constituye un desafío biológico, una situación estresante desde el punto de vista mental y físico. El mantenimiento de la performance depende de la disponibilidad de los carbohidratos y del oxígeno, hidratación adecuada y temperatura interna constante entre 37 y 38 grados centígrados. La disipación de calor producido por el metabolismo que ocurre a través del aumento del flujo de sangre para mantener la temperatura cerebral constante constituye un problema permanente. Se ha verificado experimentalmente que la energía requerida para conducir un auto de carrera es similar a la requerida para practicar un deporte como el voleibol. Durante una carrera, el individuo está expuesto a un microambiente caliente dentro de la cabina que puede llegar hasta los 50 grados centígrados generado por fuentes de calor como las mecánicas y las ambientales. El bloque del sudor por el mameluco resulta en humedad y disconfor personal, lo que implica un mayor esfuerzo personal para conducir el auto. Las medidas contra el calor comienzan antes de la carrera, cuidando el estado nutricional, la hidratación y principalmente el acondicionamiento físico a través de ejercicios aeróbicos regulares y adecuados, que permitan aumentar la capacidad de trabajo y la tolerancia al calor, lo que resulta en una menor fatiga durante la carrera. Otro procedimiento importante debería ser la aclimatación de los pilotos en ambientes calientes y húmedos. Se debe realizar lo posible en el acondicionamiento del vehículo para respetar el sistema de banderas de advertencia para los riesgos de hipertermia. En conclusión, si ahora Ayrton Senna fuera un individuo con mayor riesgo de desarrollar hipertermia, independientemente de otras causas, no parece haber habido tiempo suficiente en la carrera para

  9. Modeling and design aspects of active caloric regenerators

    Science.gov (United States)

    Engelbrecht, Kurt

    2015-03-01

    A cooling device based on a solid caloric material using, for example, the elastocaloric, magnetocaloric, barocaloric or electrocaloric effect has the potential to replace vapor-compression based systems for a variety of applications. Any caloric device using a solid refrigerant may benefit from using a regenerative cycle to increase the operating temperature span. This presentation shows how all active caloric regenerators can be modeled using similar techniques and how they are related to passive regenerator performance. The advantages and disadvantages of using a regenerative cycle are also discussed. The issue of hysteresis in caloric materials is investigated from a system/thermodynamic standpoint and the effects on cooling power and efficiency are quantified using a numerical model of an active regenerator using model caloric materials with assumed properties. The implementation in a working device will be discussed for elastocaloric and magnetocaloric cooling devices. It is shown that demagnetization effects for magnetocaloric systems and stress concentration effects in elastocaloric system reduce the overall effect in the regenerator and care must be taken in regenerator design for both technologies. Other loss mechanisms outside the regenerator such as heat leaks are also discussed. Finally, experimental results for active magnetic regenerative cooler are given for a range of operating conditions. The most recently published device uses a regenerator consisting of Gd and three alloys of GdY and has demonstrated a COP over 3.

  10. Variación espacial y estacional de grupos funcionales de bacterias cultivables del suelo de un bosque tropical seco en México

    Directory of Open Access Journals (Sweden)

    Noé Manuel Montaño

    2013-03-01

    Full Text Available Los bosques tropicales secos tienen una amplia heterogeneidad ambiental y por lo tanto se podría esperar una variación temporal y espacial en la abundancia y tipo de grupos bacterianos activos. Se evaluó, durante dos años consecutivos, el efecto de la estacionalidad de la lluvia sobre algunos grupos bacterianos cultivables y nutrimentos del suelo en dos posiciones topográficas (crestas vs laderas en el bosque tropical seco, Chamela Jalisco, México. La hipótesis fue que la variación temporal y espacial de la disponibilidad de recursos afectaría la abundancia de los grupos bacterianos funcionales (heterótrofas totales, celulolíticas, solubilizadores de fosfatos y nitrificantes del suelo. En las crestas, el suelo fue más orgánico y con mayor concentración de nutrimentos totales y C orgánico lábil que en la ladera, registrando más bacterias heterótrofas y solubilizadoras de fosfato. En ambas posiciones topográficas la concentración de C y nutrimentos, así como el número de bacterias heterótrofas y solubilizadoras de P, decrecieron de la estación seca a la lluviosa en ambos años. En contraste, las bacterias nitrificantes fueron mayores en el suelo de la ladera, y al igual que las celulolíticas, tuvieron un patrón estacional opuesto a las bacterias heterótrofas, asociado a la disminución del C lábil y de la calidad de la materia orgánica. En conclusión, se sugiere que el relieve, la estacionalidad y la variación inter-anual de la lluvia regulan interactivamente la relación entre el C disponible y la estructura de las comunidades bacterianas del suelo en el bosque tropical seco de Chamela.

  11. Procedimiento para la extracción de gluten contenido en alimentos, procesados y no procesados por calor, compatible con un ensayo de inmunoabsorción ligado a enzimas, composición y kits que comprenden dicha composición

    OpenAIRE

    López Villar, Elena; Llorente Gómez, María de las Mercedes; Méndez Cormán, Enrique

    2001-01-01

    La presente invención se refiera a, en general, el análisis de alimentos para enfermos celiacos, y, especialmente, se refiere a un procedimiento para la extracción de gluten de alimentos, compatible con un ensayo de inmunoabsorción ligado a enzimas (ELISA), a composiciones adecuadas para la puesta en práctica de dicho procedimiento, a kits que comprenden dichas composiciones y a un procedimiento para la cuantificación por ELISA del gluten presente en los alimentos.

  12. DETERMINATION OF A MATHEMATICAL MODEL TO ESTIMATE THE AREA AND DRY WEIGHT OF THE LEAF LIMBO OF Prunus persica CV. Jarillo DETERMINACIÓN DE UN MODELO MATEMÁTICO PARA LA ESTIMACIÓN DEL ÁREA FOLIAR Y PESO SECO DEL LIMBO DE Prunus persica CV. Jarillo

    Directory of Open Access Journals (Sweden)

    Enrique Quevedo García

    2012-06-01

    Full Text Available Abstract. A study was conducted to determine the variables that estimated the leaf limbo area and the leaf limbo dry weight of peach Prunus persica (L. Batsch cv. Jarillo. Fifty leaves, aged 2.5 months, were selected and measured: leaf limbo length and width, petiole length, leaf length, petiole diameter, leaf limbo fresh weight, petiole fresh weight, leaf fresh weight, leaf limbo dry weight, petiole dry weight, leaf dry weight, length/width limbo, petiole length/limbo length and leaf limbo area. The results allowed to obtain regression equations for estimating the leaf area and the limbo dry weight. Using the lineal models LA = b1 + b2 (LLL x LLW and LA= b1+ b2LLL + b3LLW a leaf area equation was determined. Alternative models to calculate limbo dry weight were evaluated LLDW = -b1+ b2 LLFW and LLDW= - b1 + b2LLL + b3PL. The best equations found with an R2 of 0.99 were LA = 1.572 + 0.65169(LLL x LLW, LA=-23.106+2.8064LLW + 3.6761LLL and LLDW = -0.002+0.401(LLFW.Resumen. Se realizó un estudio para determinar las variables que estimaran el área del limbo foliar y el peso seco del limbo de durazno Prunus persica (L. Batsch cv. Jarillo. Se seleccionaron cincuenta hojas con 2,5 meses de edad, fueron medidos: ancho del limbo, longitud del limbo, longitud del peciolo, longitud hoja, diámetro peciolo, peso fresco del limbo, peso fresco del peciolo, peso fresco de la hoja, peso seco del limbo, peso seco peciolo, peso seco de la hoja, longitud /ancho limbo, longitud del peciolo/longitud del limbo, área foliar del limbo. Los resultados alcanzados permitieron obtener ecuaciones de regresión para estimar el área foliar del limbo y el peso seco del limbo. Se halló una ecuación para la determinación del área foliar del limbo con los modelos lineales LA = b1 + b2 (LLL x LLW y LA= b1 + b2LLL + b3LLW. También se evaluaron modelos alternativas para calcular el peso seco del limbo, LLDW = -b1+ b2LLFW y LLDW= - b1 + b2LLL + b3PL. Las mejores ecuaciones

  13. Caloric restriction and exercise "mimetics'': Ready for prime time?

    Science.gov (United States)

    Handschin, Christoph

    2016-01-01

    Exercise and diet are powerful interventions to prevent and ameliorate various pathologies. The development of pharmacological agents that confer exercise- or caloric restriction-like phenotypic effects is thus an appealing therapeutic strategy in diseases or even when used as life-style and longevity drugs. Such so-called exercise or caloric restriction "mimetics" have so far mostly been described in pre-clinical, experimental settings with limited translation into humans. Interestingly, many of these compounds activate related signaling pathways, most often postulated to act on the common downstream effector peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) in skeletal muscle. In this review, resveratrol and other exercise- and caloric restriction "mimetics" are discussed with a special focus on feasibility, chances and limitations of using such compounds in patients as well as in healthy individuals. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Coeficientes de transferencia de calor en enfriadores de mineral laterítico a escala piloto

    Directory of Open Access Journals (Sweden)

    Ángel Legrá-Legrá

    2009-03-01

    Full Text Available En la Planta de Hornos de Reducción de la empresa niquelera Ernesto Guevara las elevadas temperaturas del mineral reducido a la salida de los enfriadores (coolers afectan el desarrollo eficiente del proceso de lixiviación. Se realizó una investigación, a escala piloto, en los enfriadores de mineral reducido con el fin de evaluar el comportamiento de los parámetros de transferencia de calor que caracterizan el proceso; para ello se registraron los valores de temperatura del agua y del flujo y la temperatura del mineral, tanto a la entrada como a la salida de la instalación, para valores de flujos de 10 y 19 l/min. Como resultado se obtuvo el procedimiento de cálculo para determinar los coeficientes superficiales de transferencia de calor por unidad de longitud. Se encontró que en los enfriadores de mineral reducido predominan la conducción y radiación del mineral a la pared interior del cilindro cubierta por el sólido así como la convección y evaporación del agua al medio que permite dirigir las acciones hacia estos elementos para aumentar la eficiencia de la instalación.

  15. Manejo prehospitalario de las lesiones causadas por el calor

    OpenAIRE

    Gómez Ruano, Juan Carlos

    2017-01-01

    Una de las mayores causas de morbilidad y mortalidad de personas cada verano en nuestro país y en todo el mundo son las enfermedades producidas por el calor, en especial el golpe de calor. Estas enfermedades son ocasionadas por exposiciones prolongadas al sol o a altas temperaturas que junto a otras causas como un consumo disminuido de líquidos, abuso de alcohol, utilización de demasiada ropa o ejercicio físico intenso pueden conducirnos a la muerte. Los primeros signos y síntomas de las e...

  16. Constrained caloric curves and phase transition for hot nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Borderie, B., E-mail: borderie@ipno.in2p3.fr [Institut de Physique Nucléaire, CNRS-IN2P3, Université Paris-Sud 11, F-91406 Orsay Cedex (France); Piantelli, S. [INFN Sezione di Firenze, 50019 Sesto Fiorentino (Italy); Rivet, M.F. [Institut de Physique Nucléaire, CNRS-IN2P3, Université Paris-Sud 11, F-91406 Orsay Cedex (France); Raduta, Ad.R. [National Institute for Physics and Nuclear Engineering, RO-76900 Bucharest-Magurele (Romania); Ademard, G. [Institut de Physique Nucléaire, CNRS-IN2P3, Université Paris-Sud 11, F-91406 Orsay Cedex (France); Bonnet, E. [GANIL, (DSM-CEA/CNRS-IN2P3), F-14076 Caen Cedex (France); Bougault, R. [LPC Caen, ENSICAEN, Université de Caen, CNRS-IN2P3, F-14050 Caen Cedex (France); Chbihi, A.; Frankland, J.D. [GANIL, (DSM-CEA/CNRS-IN2P3), F-14076 Caen Cedex (France); Galichet, E. [Institut de Physique Nucléaire, CNRS-IN2P3, Université Paris-Sud 11, F-91406 Orsay Cedex (France); Conservatoire National des Arts et Métiers, F-75141 Paris Cedex 03 (France); Gruyer, D. [GANIL, (DSM-CEA/CNRS-IN2P3), F-14076 Caen Cedex (France); Guinet, D.; Lautesse, P. [Université Claude Bernard Lyon 1, Institut de Physique Nucléaire, CNRS-IN2P3, F-69622 Villeurbanne Cedex (France); Le Neindre, N.; Lopez, O. [LPC Caen, ENSICAEN, Université de Caen, CNRS-IN2P3, F-14050 Caen Cedex (France); Marini, P. [GANIL, (DSM-CEA/CNRS-IN2P3), F-14076 Caen Cedex (France); and others

    2013-06-10

    Simulations based on experimental data obtained from multifragmenting quasi-fused nuclei produced in central {sup 129}Xe+{sup nat}Sn collisions have been used to deduce event by event freeze-out properties in the thermal excitation energy range 4–12 AMeV [S. Piantelli, et al., INDRA Collaboration, Nucl. Phys. A 809 (2008) 111]. From these properties and the temperatures deduced from proton transverse momentum fluctuations, constrained caloric curves have been built. At constant average volumes caloric curves exhibit a monotonic behaviour whereas for constrained pressures a backbending is observed. Such results support the existence of a first order phase transition for hot nuclei.

  17. DISTRIBUCIÓN ESPACIAL DEL BOSQUE SECO TROPICAL EN EL VALLE DEL CAUCA, COLOMBIA

    Directory of Open Access Journals (Sweden)

    Diana Patricia ALVARADO-SOLANO

    2015-01-01

    Full Text Available En el departamento del Valle del Cauca, la distribución de Bosque Seco Tropical (BsT se ha asociado al valle geográfico del río Cauca ubicado en la zona plana. Actualmente en esta zona, su cobertura se ha reducido a pocos relictos que se encuentran bajo alguna figura de conservación y mantienen áreas representativas de las formaciones vegetales típicas de este bioma. Este trabajo se enfocó en el reconocimiento de la distribución espacial de formaciones vegetales de BsT en el departamento del Valle del Cauca. Se empleó información cartográfica secundaria para reconocer los biomas, ecosistemas y usos del suelo del área de estudio y en zonas adyacentes del piedemonte y montañas. Un modelo digital de elevaciones fue utilizado para realizar análisis altitudinales. En un sistema de información geográfico se aplicaron técnicas de geoprocesamiento y análisis geoespacial entre la información cartográfica y satelital. Los resultados evidencian que pese al avanzado deterioro de las coberturas de bosque seco en la zona plana, alrededor del 80 % se localiza en ecosistemas de montaña, específicamente en zonas de transición hacia bosques húmedos. A futuro, el potencial de estas áreas deberá evaluarse para ser incluidas en estrategias de conservación y restauración del bosque seco así como en el diseño de procesos adaptativos frente al cambio climático.

  18. El trabajo teológico y docente del profesor Lucas F. Mateo-Seco

    OpenAIRE

    Aranda, A. (Antonio); Maspero, G. (Giulio)

    2006-01-01

    Este artículo pone de relieve la singular trayectoria intelectual y académica del Prof. Lucas F. Mateo Seco, analizando en primer lugar las constantes teológicas de su obra investigadora, en la que, sin duda, debe ser destacada su importante producción en torno al pensamiento de S. Gregorio de Nisa. Más tarde, tras hacer referencia a la obra manualística del Autor, cuyo vértice es su imponente tratado: “Dios Uno y Trino”, se pasa revista a los otros campos ...

  19. 4,5-seco-guaiane and a nine-membered sesquiterpene lactone from Holostylis reniformis.

    Science.gov (United States)

    Pereira, Marcos D P; da Silva, Tito; Lopes, Lucia M X; Krettli, Antoniana U; Madureira, Lucas S; Zukerman-Schpector, Julio

    2012-11-27

    Root extracts of Holostylis reniformis (Aristolochiaceae) yielded three new natural sesquiterpenes, a sesquiterpene with an unusual carbon skeleton, 4,5-seco-guaiane (7-epi-11-hydroxychabrolidione A, 1), a nine-membered lactone with new carbon skeleton (holostylactone, 2), and a new megastigmane [(6S,7E)-6,9-dihydroxy-10-(2'-hydroxy-ethoxy)-4,7-megastigmadien-3-one, 3], together with bulnesol and sitosterol-3-O-β-D-glucopyranoside. The structures of these compounds were determined by spectroscopic analyses and B3LYP/STO-3G** theoretical studies.

  20. Prevention of mammary tumorigenesis by intermittent caloric restriction: does caloric intake during refeeding modulate the response?

    Science.gov (United States)

    Cleary, Margot P; Hu, Xin; Grossmann, Michael E; Juneja, Subhash C; Dogan, Soner; Grande, Joseph P; Maihle, Nita J

    2007-01-01

    Chronic caloric restriction (CCR) prevents mammary tumorigenesis in rodents, but a protective effect for intermittent caloric restriction (ICR) is less well documented. We recently reported that ICR reduced mammary tumor (MT) incidence of mouse mammary tumor virus-transforming growth factor (MMTV-TGF)-alpha mice to a greater extent than did CCR. Here, we repeated this protocol and obtained serum and tissue samples. Ad libitum (AL) MMTV-TGF-alpha mice were fed AIN-93M diet. Beginning at 10 weeks of age, ICR mice received isocaloric AIN-93M-mod diet (2-fold increases in protein, fat, vitamins, and minerals) at 50% of ad libitum for 3 weeks followed by 3 weeks refeeding with AIN-93M diet. CCR mice were pair-fed AIN-93M:AIN-93M-mod (2:1) matching intakes for restriction/refeeding cycles. Mice were sacrificed for MT size, at 79 (end of 12th restriction) or at 80 (1 week after 12th refeeding) weeks of age. AL and ICR-80 mice had heavier body weights than ICR-79 and CCR mice (P food intakes of ICR and CCR mice were reduced 12% and 15% versus AL mice (P food than did AL mice during refeeding. MT incidence was 84%, 13%, and 27% for AL, ICR, and CCR mice, respectively. MT weight (P < 0.0011) and number (P < 0.01) were higher for AL mice compared with ICR and CCR mice. AL and ICR-80 mice had similar serum IGF-I levels, but only AL values were higher than those of ICR-79 and CCR mice (P < 0.0017). ICR mice had more MT DNA breaks compared with AL and CCR mice, suggesting enhanced apoptosis (P < 0.02). AL mice had higher mammary fat pad ObR and ObRb leptin receptor mRNA expression than did ICR and CCR mice (P < 0.001), but there was no effect on MTs. These results confirm that ICR prevents development of MTs to a greater extent than does CCR, although "overeating" during refeeding may compromise this protection.

  1. PROCEDIMIENTO DE CALIBRACIÓN EN TEMPERATURA Y FLUJO DE CALOR DE UN CALORÍMETRO DIFERENCIAL DE BARRIDO (DSC

    Directory of Open Access Journals (Sweden)

    Pablo E. Reynoso

    2016-01-01

    Full Text Available El calorímetro diferencial de barrido no es un dispositivo de medición absoluta, por lo que su utilización requiere indispensable mente una calibración. En esta contribución se presenta un procedimiento de calibración para el cual s e consideraron las temperaturas y calores de fusión aceptados en la literatura de 5 materiales puros . S e prepararon 6 muestras de dife rentes masas para cada material y s e sometió cada una de ellas a ci clos de calentamiento , desde temperatura ambiente hasta 50 ºC por encima de las temperaturas de fusión , utilizando 6 velocidades distintas por cada probeta. Luego, p ara determinar una relación de ajuste entre los datos experimentales obtenidos y los valores aceptados , se utilizó un método de regresión no lineal mediante un procedimiento matricial desarrollado en el entorno MATLAB . Los resultados obtenidos muestran una corrección con una desviación estándar de 1,2 ºC para el ajuste en temperatura y 2,1 5 J/g para el flujo de calor.

  2. Dal calore all'entropia una introduzione alla termodinamica

    CERN Document Server

    Vicentini Missoni, Matilde

    1992-01-01

    Panta rei : processi ed equilibrio ; l'universo termodinamico : l'aspetto processuale ; il punto di vista dei processi come bilancio tra proprietà dell'equilibrio ; il fluire dell'energia ; automobili, frigoriferi e pompe di calore : informazioni tecnologiche ; e allora ? l'entropia ; la termostatica come teoria assiomatica ; la termodinamica dei processi.

  3. Modelo matemático de la transferencia de calor para predecir el perfil de durezas en probetas Jominy

    Directory of Open Access Journals (Sweden)

    López, E.

    2013-04-01

    Full Text Available The heat transfer coefficient was estimated at the bottom surface at Jominy bar end quench specimen by solution of the heat inverse conduction problem. A mathematical model based on the finite-difference method was developed to predict thermal paths and volume fraction of transformed phases. The mathematical model was codified in the commercial package Microsoft Visual Basic v. 6. The calculated thermal path and final phase distribution were used to evaluate the hardness distribution along the AISI 4140 Jominy bar.En el presente trabajo se estimó el coeficiente de transferencia de calor en la superficie que se encuentra en contacto con el chorro de agua en la probeta Jominy mediante la solución del problema inverso de conducción de calor. Con el objetivo de predecir los perfiles térmicos y las fracciones de fase transformadas se formuló un modelo matemático con el método de diferencias finitas y se codificó en el software comercial Microsoft Visual Basic v. 6. Los perfiles térmicos y las fracciones de fase calculadas se utilizaron para predecir el perfil de durezas en una probeta Jominy de acero AISI 4140 mediante el uso de correlaciones empíricas.

  4. Isolated directional preponderance of caloric nystagmus: I. Clinical significance.

    Science.gov (United States)

    Halmagyi, G M; Cremer, P D; Anderson, J; Murofushi, T; Curthoys, I S

    2000-07-01

    To determine the clinical significance of an isolated directional preponderance (DP) on bithermal caloric testing. An isolated caloric DP was defined as a DP, calculated according to the standard Jongkees formula, of > or = 40%, with a spontaneous nystagmus (SN) in darkness of or = 40%. This was followed by a review of the clinical data on the 144 patients identified with such a result and then by a telephone or postal follow-up study of these patients. The study group eventually comprised 114 patients; these were patients in whom a clinical diagnosis could be made at the time the caloric test was done, or who responded to requests for follow-up information. The 34 patients in whom a clinical diagnosis could not be made at the time of the caloric test, and who did not respond to requests for follow-up information, were excluded. A balance disorders clinic in a tertiary referral hospital. All patients underwent standard bithermal caloric testing. Some of the patients also underwent rotational testing. A clinical diagnosis for the cause of the isolated DP, made either at the time of the caloric test or on the basis of information supplied at follow-up by the patient or by the referring physician. Of 114 patients, 39 had benign paroxysmal positioning vertigo, 14 had Ménière's disease, and 5 had migrainous vertigo. Five patients had central nervous system (CNS) disorders, and this was clinically apparent at the time of the caloric test in 4, so that only 1 patient with an isolated DP developed evidence of a CNS disorder after the caloric test was done. In the other 54 patients, no definite diagnosis could be made, but 41 of these 54 were either completely well or much better at follow-up. An isolated DP on caloric testing is usually a transient, benign disorder. About half the patients with an isolated DP have either Ménière's disease or benign paroxysmal positioning vertigo; in most of the other half, no definite diagnosis is made but most of these patients will

  5. Análisis de la incertidumbre del poder calorífico en un motor de combustión interna alternativo

    OpenAIRE

    YILMAZ SOÑORA, NARIN

    2017-01-01

    [ES] Dentro del marco del diagnóstico de la combustión, es interesante el análisis de la incertidumbre del poder calorífico en un motor de combustión interna alternativo. Con ello, se pretende conocer con mayor certeza la energía aprovechable de la cual se dispone en un proceso de combustión. El objetivo de este trabajo es observar la influencia del fenómeno de la disociación sobre el poder calorífico en un motor de combustión interna alternativo. Para ello, a través de las herram...

  6. O retorno ao passado em Barco a seco e o jogo de construção e desconstrução narrativa

    Directory of Open Access Journals (Sweden)

    Carlos Palacios

    2016-01-01

    Full Text Available El ensayo analiza el libro Barco a seco (2001, de Rubens Figueiredo, y se centra en el conflicto entre las muchas narrativas que se construyen en la novela a través de la mediación de la protagonista Gaspar Dias. El conflicto se produce en torno a la voluntad de Gaspar de volver al pasado y construir narrativas basadas en preceptos realistas, buscando una verdad única y sólida, mientras que él debe recurrir al acto de la creación, que establece una relación distinta con la idea de la verdad. Para entender esta contradicción, que genera la construcción y deconstrucción del ciclo narrativo, el ensayo centra su análisis en las ideas de Octavio Paz sobre las relaciones de la obra de arte con el tiempo, en la discusión que Andreas Huyssen propone sobre la musealización del pasado y en la teoría de la historia del Bastardo de Marthe Robert.

  7. Estudio comparativo de la determinación del tamaño de partícula por dos métodos : tamizado en seco y disfracción láser

    OpenAIRE

    Diana Míguez Carames; Shirley Cabrera; Ricardo Irigaray

    2011-01-01

    El objetivo de este trabajo fue comparar el desempeño analítico de la tecnología de medición de tamaño de partícula por difracción láser con la técnica clásica de tamizado en seco para partículas superiores a 80 micras. Se utilizó arena como muestra de referencia interna. El procedimiento mecánico se realizó con equipo vibrador de tamices durante 15 minutos y batería de tamices estándar ASTM números 20, 40, 70 y 170. La determinación por difracción tri-laser, que implica hacer incidir tres ha...

  8. A new 3,4-seco-oleanane-type triterpenoid with an unusual enedione moiety from Hypericum ascyron.

    Science.gov (United States)

    Chen, Chunmei; Wei, Guangzheng; Zhu, Hucheng; Guo, Yi; Li, Xiao-Nian; Zhang, Jinwen; Liu, Yanfei; Yao, Guangmin; Luo, Zengwei; Xue, Yongbo; Zhang, Yonghui

    2015-06-01

    A novel 3,4-seco-oleanane-type triterpenoid named 3,4-seco-olean-13(18)-ene-12,19-dione-3-oic acid (1), bearing an unusual enedione moiety, was isolated from the aerial parts of Hypericum ascyron, together with a known feiedelane-type triterpenoid friedelin (2). The structure of 1 with absolute configuration was elucidated on the basis of spectroscopic methods and a single-crystal X-ray diffraction analysis. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. INTERACCIÓN COLIBRÍ-FLOR EN TRES REMANENTES DE BOSQUE TROPICAL SECO (BST DEL MUNICIPIO DE CHIMICHAGUA (CESAR, COLOMBIA

    Directory of Open Access Journals (Sweden)

    DANIEL LEÓN-CAMARGO

    2015-06-01

    Full Text Available Se caracterizó la interacción colibrí-planta en tres remanentes de bosque tropical seco (BsT, ubicados en el municipio de Chimichagua (Cesar, Colombia con base en la observación de las visitas a los recursos florales y en los análisis de las cargas de polen en el pico y en otras partes del cuerpo de las aves. Se registró la época de floración y la abundancia de flores producidas por las plantas utilizadas por los colibríes y se midió la cantidad y calidad del néctar. En cinco muestreos que cubrieron la variabilidad de la precipitación en la zona de estudio, se capturaron a 17 individuos. Se realizaron 218 observaciones (visitas de dos especies de colibríes Lepidopyga goudoti y Phaethornis anthophilus, los cuales visitaron a 31 especies de plantas. Para el caso de las observaciones sobre visitas de los colibríes a las plantas, Arrabidaea cf. corallina fue la más importante (IVIR=0.14840 en los tres remanentes de vegetación estudiados, seguida por Aphelandra pulcherrima (IVIR=0.05356 y Pogonopus speciosus (IVIR=0.02773. Otra especie importante pero con valores bajos fue Cochlospermum vitifolium. De acuerdo con los análisis de cargas de polen, el recurso más importante fue Pogonopus speciosus con un valor de IVIR=0.29643, seguido por Aphelandra pulcherrima (IVIR=0.09286 y Hemistylus cf. odontophylla (IVIR=0.03294. En el análisis general para los tres sitios (Tabla 3, los recursos más importantes para los colibríes fueron Pogonopus speciosus (IVIR=0.06207, Aphelandra pulcherrima (IVIR=0.06021 y Cochlospermum vitifolium (IVIR=0.01095. Lepidopyga goudoti utiliza 22 especies de plantas, mientras que P. anthophilus solamente utiliza siete. Las flores visitadas fueron en su mayoría tubulares con colores brillantes y contrastantes como el rojo, el morado y el violeta y se encontró buen ajuste entre su tamaño y la longitud y la forma del pico de los colibríes. También se presentaron visitas a flores de color blanco y amarillo como

  10. VARIACIÓN DE LA CONDUCTIVIDAD HIDRÁULICA SATURADA DE ARENAS CON EL CONTENIDO DE FINOS LIMOSOS

    OpenAIRE

    José Alfredo Espinoza Meléndez; Virgilio Rubio Nieblas; Alfredo Francisco Espinoza Mezquita

    2016-01-01

    Este artículo presenta la variación de la conductividad hidráulica saturada de arenas finas con el contenido de finos y con el grado de acomodo, en muestras remoldeadas. Las muestras de suelo se formaron con la humedad óptima y peso volumétrico seco correspondiente a la relación de vacíos del grado de acomodo de la arena fina. La conductividad hidráulica saturada se determinó con el método del permeámetro de carga constante y con el de carga variable. No hubo diferencias significativas entre ...

  11. Dietas a base de forraje tradicional y nopal (Opuntia spp. enriquecido con proteínas para alimentar cabras

    Directory of Open Access Journals (Sweden)

    Arnoldo Flores-Hernández

    2017-01-01

    Full Text Available El objetivo fue determinar la composición química de las dietas y su efecto en la ganancia de peso vivo, consumo y rechazo de alimento. El estudio se realizó mediante un diseño completamente azar con tres repeticiones y como factor principal tres dietas cuyos componentes fueron : dieta 1 40% heno de alfalfa + 60% heno de sorgo, dieta 2 40% nopal seco natural + 60 % heno de sorgo y dieta 3 40% nopal seco enriquecido co n proteínas + 60% heno de sorgo . Los resultados mostraron que la dieta de nopal enriquecido con proteínas y la dieta de nopal seco natural poseen una calidad nutritiva mayor, pero las condiciones de secado y/o almacenamiento tuvieron efecto en la calidad de l os componentes de las dietas evaluadas. La ganancia de peso vivo fue mayor en cabras alimentadas con la dieta de nopal - E , pero el porcentaje de alimento rechazado (menor palatabili dad fue mayor para esta dieta. La ganancia de peso vivo fue menor en alfalfa y nopal seco natural , respectivamente . La ganancia de peso y el tiempo de alimentación mostraron correlación positiva y significativa ; sin embargo, se debe determinar el tiempo óptimo de alimentación y evaluar el costo - beneficio de las dietas utilizadas.

  12. DETERMINACIÓN EXPERIMENTAL DE LA CANTIDAD DE CALOR EMITIDA POR UN CIRCUITO ELECTRÓNICO EXPERIMENTAL MEASUREMENT OF THE AMOUNT OF HEAT GENERATED BY AN ELECTRONIC CIRCUIT

    Directory of Open Access Journals (Sweden)

    Jeison Marín

    2012-06-01

    Full Text Available El presente artículo describe un calorímetro que en la actualidad se utiliza para la determinación experimental de la cantidad de calor generado por circuitos electrónicos con la particularidad de permitir la entrada de potencia eléctrica al circuito electrónico bajo ensayo, para poder hacer seguimiento de su dinámica de generación de calor por efecto Joule. Para ello, se construyeron varios circuitos electrónicos básicos y cuyos resultados se presentan. Se logró de esta manera disponer de un sistema que permite contrastar las predicciones teóricas realizadas por un diseñador en cuanto a la generación de calor, frente a resultados experimentales.This article describes a calorimeter created for the experimental determination of the amount of heat generated by an electronic circuit. It has the particularity of allowing the power input to the electronic circuit under experiment, with the purpose of making possible to follow its dynamic heat flows generation by Joule effect. Several simple electronic circuits were making and their results are presented. In this way, there is now available a system which allows to evaluate the proposed theoretical predictions done by a designer and related to the heat generation, against experimental results.

  13. A Single Oxidosqualene Cyclase Produces theSeco-Triterpenoid α-Onocerin.

    Science.gov (United States)

    Almeida, Aldo; Dong, Lemeng; Khakimov, Bekzod; Bassard, Jean-Etienne; Moses, Tessa; Lota, Frederic; Goossens, Alain; Appendino, Giovanni; Bak, Søren

    2018-02-01

    8,14- seco -Triterpenoids are characterized by their unusual open C-ring. Their distribution in nature is rare and scattered in taxonomically unrelated plants. The 8,14- seco -triterpenoid α-onocerin is only known from the evolutionarily distant clubmoss genus Lycopodium and the leguminous genus Ononis , which makes the biosynthesis of this seco -triterpenoid intriguing from an evolutionary standpoint. In our experiments with Ononis spinosa, α-onocerin was detected only in the roots. Through transcriptome analysis of the roots, an oxidosqualene cyclase, OsONS1, was identified that produces α-onocerin from squalene-2,3;22,23-dioxide when transiently expressed in Nicotiana bethamiana In contrast, in Lycopodium clavatum , two sequential cyclases, LcLCC and LcLCD, are required to produce α-onocerin in the N. benthamiana transient expression system. Expression of OsONS1 in the lanosterol synthase knockout yeast strain GIL77, which accumulates squalene-2,3;22,23-dioxide, verified the α-onocerin production. A phylogenetic analysis predicts that OsONS1 branches off from specific lupeol synthases and does not group with the known L. clavatum α-onocerin cyclases. Both the biochemical and phylogenetic analyses of OsONS1 suggest convergent evolution of the α-onocerin pathways. When OsONS1 was coexpressed in N. benthamiana leaves with either of the two O. spinosa squalene epoxidases, OsSQE1 or OsSQE2 , α-onocerin production was boosted, most likely because the epoxidases produce higher amounts of squalene-2,3;22,23-dioxide. Fluorescence lifetime imaging microscopy analysis demonstrated specific protein-protein interactions between OsONS1 and both O. spinosa squalene epoxidases. Coexpression of OsONS1 with the two OsSQE s suggests that OsSQE2 is the preferred partner of OsONS1 in planta. Our results provide an example of the convergent evolution of plant specialized metabolism. © 2018 American Society of Plant Biologists. All Rights Reserved.

  14. Entrevista con Patricia Ariza

    Directory of Open Access Journals (Sweden)

    Esperanza Londoño La Rotta

    2017-01-01

    Full Text Available Pensamiento, Palabra y Obra entrevista a una artista, feminista y activista política, quien como mujer y artista ha permitido pensar el arte más allá de un simple espectáculo. Toda una vida dedicada al teatro y a darle voz, a través de sus obras, a víctimas del conflicto colombiano, defensora de derechos humanos; además de hacer evidente en su vida y a través de la plataforma “Artistas por la paz”, las múltiples relaciones que se pueden establecer entre el arte, la construcción de paz y la resolución de conflictos. Hablamos en su casa, en medio del calor de la bienvenida con Patricia Ariza, directora del festival alternativo de teatro, de Mujeres en Escena y de la Corporación Colombiana de Teatro, entre otras muchas actividades que voluntariamente su espíritu libertario ha asumido. Esta entrevista se realizó antes del 2 de octubre, pero con la revisión de los acuerdos que propició el plebiscito ganado por una ínfima minoría por el no, sigue siendo vigente este planteamiento.

  15. Growth-inhibiting effects of seco-tanapartholides identified in Artemisia princeps var. orientalis whole plant on human intestinal bacteria.

    Science.gov (United States)

    Cho, S-H; Na, Y-E; Ahn, Y-J

    2003-01-01

    The present work aimed at isolating antibacterial constituents from the whole plant of Artemisia princeps var. orientalis active towards nine human intestinal bacteria. The growth-inhibiting activities of materials derived from the Artemisia whole plant towards test bacteria were examined using an impregnated paper disc method. The biologically active constituents of the Artemisia whole plant were characterized as the sesquiterpene lactones seco-tanapartholides A and B by spectroscopic analysis. In a test using 1 mg per disc, seco-tanapartholides A and B produced a clear inhibitory effect against Clostridium perfringens, Bacteroides fragilis and Staphylococcus aureus. These compounds did not affect the growth of test lactic acid-producing bacteria (Bifidobacterium adolescentis, Bif. breve, Lactobacillus acidophilus and Lact. casei) and Escherichia coli, whereas weak growth inhibition towards Bif. bifidum was observed. At 0.5 mg per disc, seco-tanapartholides A and B exhibited moderate growth inhibition towards Cl. perfringens but weak growth inhibition towards Bact. fragilis and Staph. aureus. Inhibitory action of seco-tanapartholides A and B towards specific bacteria without any adverse effects on lactic acid-producing bacteria may be an indication of at least one of the pharmacological actions of A. princeps var. orientalis whole plant. These naturally occurring Artemisia whole plant-derived materials could be useful as a new preventive agent against various diseases caused by harmful intestinal bacteria such as clostridia.

  16. Perspective food addiction, caloric restriction, and dopaminergic neurotransmission

    DEFF Research Database (Denmark)

    Stankowska, Arwen Urrsula Malgorzata; Gjedde, Albert

    2013-01-01

    for a reduced cognitive reward condition. The combination of caloric restriction and food addiction imparts a high risk of relapse as a result of further reduction of dopaminergic neurotransmission and the subsequent loss of reward. As with drugs of abuse, ingestion of large quantities of sugar in circumstances...... by the relationship between dopamine receptor availability in the striatum and sensation-seeking in the form of an inverted U, suggested by recent findings, consistent with two opposite states of hypodopaminergic and hyperdopaminergic neuromodulation....

  17. Macronutrients and caloric intake in health and longevity

    OpenAIRE

    Solon-Biet, Samantha M.; Mitchell, Sarah J.; de Cabo, Rafael; Raubenheimer, David; Le Couteur, David G.; Simpson, Stephen J.

    2015-01-01

    Both lifespan and healthspan are influenced by nutrition, with nutritional interventions proving to be robust across a wide range of species. However, the relationship between nutrition, health and aging is still not fully understood. Caloric restriction is the most studied dietary intervention known to extend life in many organisms, but recently the balance of macronutrients has been shown to play a critical role. In this review, we discuss the current understanding regarding the impact of c...

  18. Strenuous exercise with caloric restriction: effect on luteinizing hormone secretion.

    Science.gov (United States)

    Williams, N I; Young, J C; McArthur, J W; Bullen, B; Skrinar, G S; Turnbull, B

    1995-10-01

    To test whether strenuous exercise with and without caloric restriction alters LH secretion, and whether these changes are apparent in the immediate post-exercise period, LH pulse parameters were studied in four moderately trained eumenorrheic women over three successive menstrual cycles. Blood samples were obtained 5 h before and 5 h after 90 min of running at 74% VO2max. Each test was preceded by a 7-d treatment of controlled diet and exercise (74% VO2max). During CONTROL, subjects were eucaloric on days 1-7, and performed no exercise on days 5-7. During STTI (short-term training increase), subjects were eucaloric and completed 90 min runs on days 5-7. During DIET/STTI, subjects consumed 60% of the calories necessary to maintain weight on days 1-7, and exercised as in STTI. A significant decrease in overall (0700-1830 h) LH pulse frequency during DIET/STTI compared with CONTROL and STTI treatments was observed. No changes were found in mean serum LH levels or peak amplitude. These results suggest that high-volume training combined with caloric restriction may predispose one to exercise-induced changes in LH pulse frequency, while adequate caloric intake may prevent these changes.

  19. Seco-B-Ring Steroidal Dienynes with Aromatic D Ring: Design, Synthesis and Biological Evaluation

    Directory of Open Access Journals (Sweden)

    Marcin Szybinski

    2017-10-01

    Full Text Available Continuing our structure-activity studies on the vitamin D analogs with the altered intercyclic seco-B-ring fragment, we designed compounds possessing dienyne system conjugated with the benzene D ring. Analysis of the literature data and the docking experiments seemed to indicate that the target compounds could mimic the ligands with a good affinity to the vitamin D receptor (VDR. Multi-step synthesis of the C/D-ring building block of the tetralone structure was achieved and its enol triflate was coupled with the known A-ring fragments, possessing conjugated enyne moiety, using Sonogashira protocol. The structures of the final products were confirmed by NMR, UV and mass spectroscopy. Their binding affinities for the full-length human VDR were determined and it was established that compound substituted at C-2 with exomethylene group showed significant binding to the receptor. This analog was also able to induce monocytic differentiation of HL-60 cells.

  20. Isotermas de adsorção do pedúnculo seco do caju

    OpenAIRE

    Alcântara,Siumara R.; Almeida,Francisco de A. C.; Silva,Flávio L. H. da; Gomes,Josivanda P.

    2009-01-01

    A atividade de água constitui um fator importante no processo de fermentação semi-sólida, haja vista sua relação com a quantidade de água disponível ao microrganismo responsável pelo metabolismo do produto, sendo necessário à obtenção de isotermas de sorção para caracterização do substrato. Ante o exposto, objetivou-se a construção das isotermas de adsorção do pedúnculo seco do caju (Anacardium occidentale L.) nas temperaturas usuais de fermentação (25, 30, 35 e 40 ºC). Ajustaram-se as isoter...

  1. Modelo de transmisión de calor por radiación en una piscina de combustible gastado mediante TRACE

    OpenAIRE

    Sanchez Saez, Francisco; Carlos Alberola, Sofía; Martorell Alsina, Sebastián Salvador; Villanueva López, José Felipe

    2013-01-01

    El trabajo desarrollado consiste en la simulación termohidráulica de una piscina de combustible gastado al producirse un transitorio de pérdida de refrigerante con pérdida de refrigeración a través del canal de transferencia. La simulación se realiza con el código Best Estimate TRACE. Para seguir la evolución del comportamiento de la piscina, una variable importante a seguir es la temperatura de vaina, cuya evolución depende del calor que consiga emitir. En esta simulación se h...

  2. Perfiles de temperatura generados por fuentes esféricas de calor durante el tratamiento del cáncer por hipertermia local

    OpenAIRE

    Giordano, Mauricio A.; Gutiérrez, Gustavo; Massa, Julio C.

    2011-01-01

    En este trabajo se derivan soluciones analíticas para el modelo de Pennes de difusión de calor en medios biológicos usando funciones de Green. El objetivo es predecir los perfiles de temperatura que se pueden obtener en tumores de forma esférica durante el tratamiento del cáncer por hipertermia usando fluidos magnéticos. El dominio matemático consta de dos regiones, la interna se corresponde con el tejido canceroso de dimensión finita; y la externa con tejido sano que se extiende ...

  3. Estudio del desgaste del flanco de carburos recubiertos y cermet durante el torneado de alta velocidad en seco del acero AISI 1045

    Directory of Open Access Journals (Sweden)

    Hernández-González, L. W.

    2011-06-01

    Full Text Available This work deals with the experimental study of the flank wear evolution of two coating carbide inserts and a cermet insert during the dry finishing turning of AISI 1045 steel with 400, 500 and 600 m/min cutting speeds. The results were analyzed using the variance analysis and lineal regression analysis in order to describe the relationship between the flank wear and machining time, obtaining the adjusted model equation. The investigation demonstrated a significant effect of cutting speed and machining time on the flank wear at high speed machining. The three coating layers insert showed the best performance while the two layers insert had the worst behaviour of the cutting tool wear at high cutting speeds.

    El objetivo de este trabajo es el estudio experimental de la evolución del desgaste del flanco respecto al tiempo de dos insertos de carburo recubiertos y un cermet durante el torneado de acabado en seco del acero AISI 1045 con velocidades de corte de 400, 500 y 600 m/min. Los resultados fueron comparados utilizando el análisis de varianza y el análisis de regresión lineal para describir la relación entre el desgaste del flanco y el tiempo de maquinado, obteniéndose la ecuación del modelo ajustado. La investigación demostró un efecto significativo de la velocidad de corte y del tiempo de maquinado en el desgaste del flanco en el maquinado de alta velocidad. El mejor desempeño se obtuvo para el carburo recubierto con tres capas, mientras que el carburo con dos capas sufrió el mayor desgaste a elevadas velocidades de corte.

  4. An In Vivo Magnetic Resonance Spectroscopy Study of the Effects of Caloric and Non-Caloric Sweeteners on Liver Lipid Metabolism in Rats

    NARCIS (Netherlands)

    Janssens, Sharon; Ciapaite, Jolita; Wolters, Justina C.; van Riel, Natal A.; Nicolay, Klaas; Prompers, Jeanine J.

    2017-01-01

    We aimed to elucidate the effects of caloric and non-caloric sweeteners on liver lipid metabolism in rats using in vivo magnetic resonance spectroscopy (MRS) and to determine their roles in the development of liver steatosis. Wistar rats received normal chow and either normal drinking water, or

  5. The urban climate: urban heat island of Salamanca El clima de las ciudades: isla de calor de Salamanca

    Directory of Open Access Journals (Sweden)

    Mª Salud Alonso García

    2004-12-01

    Full Text Available We have determined the existence of the urban heat island (UHI in a medium-sized city, with an extreme climate and few important foci of industrial pollution. It was seen that urban warming can arise in cities of these characteristics, being able to influence in the alive beings of the zone. By comparing the temperature series in an urban area and those from a nearby rural area, we studied the temporal evolution of the intensity of the UHI for the three-year period between 1996 and 1998. We detected two phenomenons: nocturnal heat island, when the difference of temperature between city and rural zone is positive, and diurnal heat island, when is negative. The most intense nocturnal heat island was seen in autumn, and the most intense diurnal heat island was seen in spring. Statistical study of the annual series corresponding to the night-time heat island permits a definition for Salamanca: a weak island, such as the one showing an intensity lower than 2.0 oC, a moderate island, if the intensity lies between 2.0 oC and 4.0 oC, and an intense island when a values greater than 4.0 oC is passed.En este trabajo se ha determinado la existencia de la isla de calor urbana (ICU, en una ciudad de tamaño medio, con un clima extremado y focos industriales de poca actividad. Con lo que se puede comprobar cómo afecta el calentamiento urbano a ciudades de estas características, pudiendo influir en los seres vivos de la zona. La existencia del fenómeno isla de calor, y su evolución en el tiempo, se han observado comparando los datos de temperatura registrados en una estación meteorológica situada en la ciudad, con los de otra estación fuera del radio de acción de la urbe, durante el período 1996-1998. Se han detectado dos fenómenos: la isla de calor nocturna, cuando la diferencia térmica entre la ciudad y la zona rural es positiva, que presenta sus valores más altos en otoño, y la isla de calor diurna, cuando la diferencia es negativa, que

  6. Solar thermal power plants for heat and electricity generation; Presentacion de plantas termosolares para generacion de calor y energia electrica

    Energy Technology Data Exchange (ETDEWEB)

    Estrada Cajigal, V. [Solartronic S. A. de C. V., Cuernavaca (Mexico); Manzini, F.; Sanchez, A. [Laboratorio de Energia Solar (IIM-UNAM), Temixco (Mexico)

    1992-12-31

    Solar thermal technology is presented for concentration into a point for the production of heat and energy in small and large scale, emphasis is made on the capacity for the combination with current technologies using fossil fuels for electricity generation and process steam, increasing the global efficiency of the power plants and notably reducing the pollutants emission to the air during the insolation hours. It is successfully compared with other solar-thermal technologies. [Espanol] Se presenta la tecnologia termosolar de concentracion puntual para produccion de calor y de energia en pequena y gran escala, se enfatiza su capacidad de combinacion con las tecnologias actuales que utilizan combustibles fosiles para produccion de electricidad y vapor de proceso, aumentando la eficiencia global de las plantas y reduciendo notablemente sus emisiones contaminantes a la atmosfera durante las horas de insolacion. Se le compara exitosamente con otras tecnologias termosolares.

  7. Análisis de la dispersión axial de masa y calor en reactores de lecho fijo

    Directory of Open Access Journals (Sweden)

    Rangel Jara Hermes Augusto

    1997-01-01

    Full Text Available Dentro del espíritu investigativo a nivel teórico del estudio de los reactores químicos, el presente trabajo desarrolla e implementa un análisis conceptual y numérico de los fenómenos de dispersión axial de calor y masa en reactores de lecho fijo. Se pretende disponer de una alternativa numérica que permita en una forma rápida y precisa la solución de las ecuaciones diferenciales junto con las respectivas condiciones de frontera del modelo matemático. Para la simulación del reactor de lecho fijo se empleó un modelo unidimensional pseudohomogeneo con parámetros aglomerados.

  8. Análisis de la dispersión axial de masa y calor en reactores de lecho fijo

    Directory of Open Access Journals (Sweden)

    Rangel Jara Hermes Augusto

    2011-06-01

    Full Text Available Dentro del espíritu investigativo a nivel teórico del estudio de los reactores químicos, el presente trabajo desarrolla e implementa un análisis conceptual y numérico de los fenómenos de dispersión axial de calor y masa en reactores de lecho fijo. Se pretende disponer de una alternativa numérica que permita en una forma rápida y precisa la solución de las ecuaciones diferenciales junto con las respectivas condiciones de frontera del modelo matemático. Para la simulación del reactor de lecho fijo se empleó un modelo unidimensional pseudohomogeneo con parámetros aglomerados.

  9. Comportamento higroscópico do resíduo seco de camarão-rosa Hygroscopic behavior of the dry residue of pink shrimp

    Directory of Open Access Journals (Sweden)

    Alan Barros Assunção

    2007-12-01

    Full Text Available Estudou-se o comportamento higroscópico do resíduo seco de camarão-rosa (Peneaus subtilis, o qual foi caracterizado como sendo rico em proteínas totais (42,59% e resíduo mineral fixo (22,01%. Foram construídas isotermas de adsorção e dessorção de umidade a 10, 25, e 40 °C. Determinou-se o valor da monocamada e o calor de dessorção, e testou-se a aplicabilidade de treze modelos matemáticos na predição dos dados de sorção. O produto apresentou isotermas do Tipo II. Os dados de adsorção mostraram que para que o produto apresente estabilidade microbiológica (a w A study was made of the hygroscopic behavior of the dry residue of pink shrimp (Peneaus subtilis, characterized as being rich in total proteins (42.59% and ash (22.01%. Adsorption and desorption isotherms were plotted at 10, 25 and 40 °C. The monolayer and desorption heat values were determined and thirteen mathematical models were fitted to experimental data to predict the sorption data. The product presented Type II isotherms. The adsorption data indicated that the product's microbiological stability (a w < 0.6 would require the dry residue to contain moisture of less than 13.0 g H2O.100 g -1 dry solids in adsorption and 14.0 g H2O.100 g -1 dry solids in desorption. The monolayer's desorption values indicated that, in order to avoid unnecessary loss of energy, the residue should not be dried to a moisture level below 7.29 g H2O.100 g-1 dry solids. The values of desorption heat indicated that large amounts of energy were not required to dry the residue to appropriate levels of moisture to attain microbiological stability (a w < 0.6. The best models for predicting the sorption isotherms of the residue were Oswin and Halsey (biparametric; GAB, modified BET, Hailwood-Horrobin, Anderson, Anderson-Hall and Gascoyne-Pethig (triparametric.

  10. Determinación del requerimiento de frío y de calor en duraznero [Prunus persica (L. Batsch.] mediante un modelo de correlación

    Directory of Open Access Journals (Sweden)

    CHAAR, J

    2012-11-01

    Full Text Available Los árboles frutales de hoja no persistente poseen un período de reposo entre los ciclos vegetativos. Para salir de reposo invernal, las yemas deben acumular primero frío (endodormancia y luego calor (ecodormancia.El objetivo de este trabajo fue determinar el requerimiento de frío y de calor en cinco cultivares de duraznero mediante un método de correlación, con datos de fecha de plena floración y temperatura del aire de siete años, en el este de Mendoza. El requerimiento de frío varió entre 914 y 1262 unidades de frío, mientras que el de calor fluctuó entre 2177 y 6490 horas grado de crecimiento. Excepto en cv. “Prima”, la variabilidad entre años del requerimiento de frío (coeficiente de variación, CV: 18,3 a 18,9% fue mayor que la correspondiente al requerimiento de calor, (CV: 6,9 a 13,9%. Los requerimientos de calor disminuyeron en años de mayor acumulación de frío e indicaron una compensación. El modelo utilizado, permite disponer de información más precisa sobre los requerimientos térmicos de los cultivares, y así poder realizar una zonificación que racionaliceel cultivo y maximice su aprovechamiento, en las áreas agroclimáticamente adecuadas.

  11. Hybrid system: Heat pump-solar air dryer for grains; Sistema hibrido: bomba de calor - calentador solar de aire para el secado de productos agricolas

    Energy Technology Data Exchange (ETDEWEB)

    Soto Gomez, Willfredo [Instituto Tecnologico de Tijuana, Tijuana (Mexico); Ortega Herrera, Jose Angel [Instituto Politecnico Nacional, Mexico, D.F. (Mexico)

    2000-07-01

    Design, building, operation and evaluation energy wise of a hybrid experimental type, with heat pump, that uses no chloride, does not destroy the ozone layer. It is solar air dryer for grains. In this research we dry rice. It has tree systems: 1.- A mechanical compression heat pump, 2.- An air solar heater, and 3.- An agriculture products dryer. The drying capacity is 20 pounds of grain /day, with a median daily solar radiation. The costs is approximately U.S. $ 6 000.00. The heat pump used 22 refrigerant first, and now works with refrigerant SUVA 9000. This refrigerant will be available this year in the I.S., it is one of the ecological class that substitutes the chlorofluorocarbonates. [Spanish] Se disena, construye, opera, y evalua energeticamente, un sistema hibrido tipo experimental, con bomba de calor que utiliza refrigerante que no contiene cloro, y no destruye la capa de ozono y un calentador solar de aire, para secar granos. En este trabajo secamos arroz. Se compone de tres sistemas: 1.- Bomba de calor por compresion mecanica, 2.- Calentador solar de aire, 3.- Secador de productos agricolas. La capacidad de secado es de 10 Kilos de granos/dia promedio. Tiene un costo aproximado de $ 60 000. La bomba de calor utiliza refrigerante 22 en una primera generacion, y actualmente opera con un refrigerante SUVA 9000, en una segunda generacion, este refrigerante se comercializara en este ano, en la Union Americana, pertenece a la familia de los llamados refrigerantes ecologicos, sustitutos de los clorofluorocarbonados.

  12. Efecto del consumo de frutos secos sobre el síndrome metabólico y la mortalidad total en la cohorte sun

    OpenAIRE

    Fernandez-Montero, A. (Alejandro); Martinez-Gonzalez, M. A.

    2013-01-01

    1. OBJETIVO GENERAL El objetivo de nuestro trabajo es estudiar el efecto del consumo de frutos secos sobre el síndrome metabólico y la mortalidad total en la cohorte SUN. 2. OBJETIVOS ESPECÍFICOS 1. Validar los datos autorreferidos sobre los componentes de SM en la cohorte SUN. 2. Estudiar la asociación entre el consumo de frutos secos y la incidencia de SM. 3. Estudiar la asociación entre el consumo de frutos secos y la mortalidad total.

  13. Reaction of (13S)-13-iodo-6beta-methoxy-3alpha,5-cyclo-13,14-seco-5alpha-androstane-14,17-dione with hydroxylamine and its application to the synthesis of new 13,14-seco steroids

    NARCIS (Netherlands)

    Khripach, V.A.; Zhabinskii, V.N.; Kuchto, A.I.; Fando, G.P.; Zhiburtovich, Y.Y.; Lyakhov, A.S.; Govorova, A.A.; Groen, M.B.; Louw, van der J.; Groot, de Æ.

    2004-01-01

    The synthesis of 13,14-seco steroids starting from easily available (13S)-13-iodo-6-methoxy-3,5-cyclo-13,14-seco-5-androsta-14,17-dione is described. The C-17 ketone was converted regioselectively into its oxime with simultaneous stereoselective deiodination at C-13. The remaining C-14 carbonyl

  14. Can we live longer by eating less? A review of caloric restriction and longevity.

    Science.gov (United States)

    Roth, Lauren W; Polotsky, Alex J

    2012-04-01

    Caloric restriction, decreasing caloric intake by 20-30%, was first shown to extend life in rats nearly 80 years ago. Since that time, limiting food intake for longevity has been investigated in species from yeast to humans. In yeast and lower animals, caloric restriction has repeatedly been demonstrated to lengthen the life span. Studies of caloric restriction in non-human primates and in humans are ongoing and initial results suggest prolongation of life as well as prevention of age-related disease. There is also data in rodents suggesting that short term caloric restriction has beneficial effects on fertility. Although caloric restriction has many positive effects on health and longevity, quality of life on a restricted diet as well as the ability to maintain that diet long term are concerns that must be considered in humans. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  15. The Lexicocalorimeter: Gauging public health through caloric input and output on social media

    CERN Document Server

    Alajajian, S E; Reagan, A J; Alajajian, S C; Frank, M R; Mitchell, L; Lahne, J; Danforth, C M; Dodds, P S

    2015-01-01

    We propose and develop a Lexicocalorimeter: an online, interactive instrument for measuring the "caloric content" of social media and other large-scale texts. We do so by constructing extensive yet improvable tables of food and activity related phrases, and respectively assigning them with sourced estimates of caloric intake and expenditure. We show that for Twitter, our naive measures of "caloric input", "caloric output", and the ratio of these measures---"caloric balance"---are all strong correlates with health and well-being demographics for the contiguous United States. Our caloric balance measure outperforms both its constituent quantities, is tunable to specific demographic measures such as diabetes rates, provides a real-time signal reflecting a population's health, and has the potential to be used alongside traditional survey data in the development of public policy and collective self-awareness. Because our Lexicocalorimeter is a linear superposition of principled phrase scores, we also show we can m...

  16. Determinación del calor isostérico para pulpa de plátano (musa paradisiaca) por isotermas de sorción

    OpenAIRE

    CIRO, HÉCTOR; OSORIO, JAIRO ALEXANDER; CORTÉS, ELKIN ALONSO

    2008-01-01

    Las isotermas de sorción para ser usadas en la simulación y diseño de procesos de secado y almacenamiento de alimentos deben ser representadas por modelos válidos dentro de las condiciones encontradas en la práctica industrial. Usando el modelo de Chung–Pfost y ajustado por desorción el calor isostérico neto y total para pulpa de plátano fueron determinados. El calor neto isotérico neto decreció con el contenido de humedad del producto variando desde 1670 kJ/kg (5%.d.b) a 215 kJ/kg (26%.d.b...

  17. Funcionamiento de un termosifón cilíndrico con distintos fluidos de trabajo

    OpenAIRE

    Arcís Tellería, José

    2010-01-01

    Actualmente, las investigaciones llevadas a cabo en el campo de la transmisión de calor mediante termosifón, tratan de conocer el comportamiento de las distintas sustancias, con el fin de optimizar dicha tecnología para la transferencia de calor. En este sentido, en el Área de Máquinas y Motores Térmicos, perteneciente al Departamento de Ingeniería Mecánica, Energética y de Materiales de la Universidad Pública de Navarra, se está llevando a cabo un proyecto de investigación con fluidos de tra...

  18. Macronutrients and caloric intake in health and longevity.

    Science.gov (United States)

    Solon-Biet, Samantha M; Mitchell, Sarah J; de Cabo, Rafael; Raubenheimer, David; Le Couteur, David G; Simpson, Stephen J

    2015-07-01

    Both lifespan and healthspan are influenced by nutrition, with nutritional interventions proving to be robust across a wide range of species. However, the relationship between nutrition, health and aging is still not fully understood. Caloric restriction is the most studied dietary intervention known to extend life in many organisms, but recently the balance of macronutrients has been shown to play a critical role. In this review, we discuss the current understanding regarding the impact of calories and macronutrient balance in mammalian health and longevity, and highlight the key nutrient-sensing pathways that mediate the effects of nutrition on health and ageing. © 2015 Society for Endocrinology.

  19. COMPORTAMIENTO DE LA VEGETACIÓN DE UN HUMEDAL (MALLÍN ENTRE PERÍODOS HÚMEDOS Y SECOS MEDIANTE ANÁLISIS METEOROLÓGICOS Y ESPECTRAL

    Directory of Open Access Journals (Sweden)

    Oscar Peña

    2008-12-01

    Full Text Available En este estudio se analiza el comportamiento meteorológico y espectral de un humedal (mallín localizado en la cuenca media del Río Catan Lil, en la provincia de Neuquén, (Argentina, en una serie de diez años que abarcan períodos hidrológicos secos-medios y húmedos. Los mallines son importantes ecosistemas naturales que históricamente se han utilizado como recurso forrajero para la ganadería extensiva en la Patagonia Argentina y que han sufrido, en la mayoría de los casos, intensos procesos de degradación. . Para evaluar el comportamiento meteorológico, se caracterizaron los años teniendo en cuenta la lluvia y la nieve caída, considerando valores totales mensuales, desde 1996/97 hasta 2005/06. El análisis espectral se realizó mediante el uso de imágenes satelitales de la serie Landsat Tm (path 232 row 087 de las series de años mencionadas. Del análisis resulta que existe una relación bastante directa entre años secos o con adelantamiento de la fusión nival y la disminución de la actividad fotosintética de la vegetación, respecto a períodos medios ó húmedos. Esto queda reflejado en los índices obtenidos mediante el proceso digital de las imágenes. La utilización de información satelital y su correlación con información meteorológica es una buena herramienta para planificar el uso de estos recursos sin causar problemas que afecten la dinámica del mallin.

  20. Relaciones ecológicas entre frutos hospederos, moscas frugívoras y parasitoides en un fragmento de bosque seco tropical

    Directory of Open Access Journals (Sweden)

    Jeferson Saavedra-Díaz

    2017-06-01

    Full Text Available Las moscas de las frutas (Tephritoidea: Tephritidae y Lonchaeidae son una de las principales plagas de la fruticultura a nivel mundial. El conocimiento de las interacciones que presentan las moscas frugívoras con sus plantas hospederas y parasitoides es necesario para el desarrollo de programas de manejo integrado de estas plagas. El objetivo de este trabajo fue describir las relaciones tritróficas (plantas hospederas, moscas frugívoras y parasitoides en un parche de bosque seco tropical en el Centro Universitario Regional del Norte del municipio de Armero-Guayabal, Tolima. Se colectaron frutos de 35 especies de plantas. Los frutos se transportaron al laboratorio y se dispusieron en forma individual para la posterior pupación y emergencia de moscas y/o parasitoides. Se registraron 2.940 larvas en frutos de 15 especies de plantas. De estas larvas se obtuvieron adultos de seis especies de Tephritidae (cinco de Anastrepha y Toxotrypana curvicauda y ocho de Lonchaeidae (seis de Neosilba y dos de Lonchaea. Los tefrítidos fueron los más abundantes y causaron los mayores porcentajes de daño (0-83,31% e índices de infestación (0-10,32 larvas/fruto y 0-463,37 larvas/kg frutos, y los lonquéidos fueron más polífagos con 12 plantas hospederas. Ambas familias compartieron hospederos y se presentaron cohabitando un mismo fruto. Cuando se encuentran en simpatría las especies de Anastrepha tienden a no compartir sus plantas hospederas o un mismo fruto. Las especies de Neosilba si comparten hospederos y frutos. Se encontraron cinco especies de parasitoides. Nuevos registros y asociaciones de plantas hospederas, moscas frugívoras y parasitoides se presentan para Colombia.

  1. Conducción transitoria con generación : simetría plana unidireccional - distribución inicial parabólica

    OpenAIRE

    Betancourt Grajales, Ramiro

    1999-01-01

    Se analiza el caso en el período no estable de una placa plana infinita de espesor 2L que intercambia calor por convección con un medio a T∞. con coeficiente convectivo o pelicular h. Su distribución de temperatura inicial es parabólica y se genera calor en su interior de manera uniforme a razón de ΦΗ W/m3. Se evidencia la rápida convergencia de la serie resultante comparando sus resultados, calculados con solo dos términos, con los obtenidos para condiciones estacionarias extremas

  2. The synthesis and pharmacological evaluation of (±-2,3-seco-fentanyl analogues

    Directory of Open Access Journals (Sweden)

    LJ. DOSEN-MICOVIC

    2004-11-01

    Full Text Available An efficient, five-step synthetic approach to various acyclic 1,3-diamines has been developed and applied to the preparation of a novel class of open-chained fentanyl analogues. The acyclic derivatives 5.1–5.5 (all new compounds were synthesized with the aim of estimating the significance of the piperidine ring for the opioid analgesic activity of anilido-piperidines. The starting b-keto-amide 1.1, prepared by the aminolysis of methyl acetoacetate with methylphenethylamine, (93 % yield, was successively reacted with NaH and BuLi, to form the highly reactive a,g-dienolate anion 1.1a. Regio and chemoselective g-alkylation of the dienolate with various primary and secondary alkyl halides furnished the b-keto-amides 1.2–1.5 (76–91 %. Reductive amination of the keto-amides 1.1–1.5 with aniline and Zn powder in acetic acid, via the enamine intermediates 2.1–2.5, afforded the b-anilino amides 3.1–3.5 (74–85 %. After reductive deoxygenation of the tertiary amide group, using in situ generated diborane, the corresponding 1,3-diamines 4.1–4.5 were obtained (87–97 %. The synthesis of (±-2,3-seco-fentanyls 5.1–5.5 was completed by N-acylation of the diamines 4.1–4.5 with propionyl chloride, followed by precipitation of the monooxalate salts (86–95 %. The parent compound, 2,3-seco-fentanyl 5.1, was found to be a 40 times less potent narcotic analgesic than fentanyl but still 5–6 times more active than morphine in rats, while i-Pr derivative 5.3 was inactive. Apart from the pharmacological significance, the general procedure described herein may afford various functionalized, 1,3-diamines as potential complexing agents and building blocks for the synthesis of aza-crown ethers.

  3. seco-Tiaminic acids B and C: Identification of two novel 3,4-seco-tirucallane triterpenoids isolated from the root of Entandrophragma congoënse (Meliaceae).

    Science.gov (United States)

    Happi, Gervais Mouthé; Talontsi, Ferdinand Mouafo; Laatsch, Hartmut; Zühlke, Sebastian; Ngadjui, Bonaventure Tchaleu; Spiteller, Michael; Kouam, Simeon Fogue

    2018-01-01

    Chemical investigation of the roots of Entandrophragma congoënse (Meliaceae) led to the isolation of two new 3,4-seco-tirucallane triterpenes, namely seco-tiaminic acids B and C (1 and 2) together with nine known compounds: 3,4-secotirucalla-21-formyl-23-oxo-4(28),7,24-trien-3-oic acid (3), methyl angolensate (4), molucensin N (5), molucensin O (6), piscidinol A (7), 7α,20(S)-dihydroxy-4,24(28)-ergostadien-3-one (8), 24-methylene-cholest-5-en-3β,7α-diol (9), entilin A (10), and entilin B (11). Their structures were determined using extensive spectroscopic methods including 1D and 2D NMR, HRMS, and CD analyses; new results were compared to existing data in the literature. The two newly identified seco-tiaminic acids showed moderate antiplasmodial and cytotoxic activities against a chloroquine-sensitive strain of the malaria parasite (Plasmodium falciparum NF54) and were cytotoxic toward an L6 rat skeletal myoblast cell line, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. NOAA TIFF Image - .75m Multibeam Backscatter, US Virgin Islands - Vieques Island (El Seco) - Project NF-09-01 - (2009), UTM 20N WGS 84

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a GeoTIFF with .75x.75 meter cell size representing the backscatter or intensity of sound returned from the seafloor in "El Seco" east of...

  5. NOAA TIFF Image - 1m Multibeam Bathymetry, US Virgin Islands - Vieques Island (El Seco) - Project NF-09-01 - (2009), UTM 20N NAD83

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a unified ESRI Geotiff with 1x1 meter cell size representing the bathymetry of El Seco, a selected portion of seafloor east of Vieques Island,...

  6. NOAA TIFF Image - 1m Multibeam Bathymetry, US Virgin Islands - Vieques Island (El Seco) - Project NF-09-01 - (2009), UTM 20N NAD83 (NCEI Accession 0131857)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset contains a unified ESRI Grid with 1x1 meter cell size representing the bathymetry of El Seco, a selected portion of seafloor east of Vieques Island,...

  7. Seco-limonoid derived from Raputia heptaphylla promotes the control of cutaneous leishmaniasis in hamsters (Mesocricetus auratus).

    Science.gov (United States)

    Granados-Falla, Diana; Gomez-Galindo, Angela; Daza, Alejandro; Robledo, Sara; Coy-Barrera, Carlos; Cuca, Luis; Delgado, Gabriela

    2016-03-01

    The rational search of novel bioactive molecules against pathogens with immunomodulatory activity is presently one of the most significant approaches to discover and design new therapeutic agents for effective control of infectious diseases, such as the infection caused by Leishmania parasites. In the present study, we evaluated the therapeutic efficacy of the recently characterized immunomodulatory compound 11α,19β-dihydroxy-7-acetoxy-7-deoxoichangin, a seco-limonoid derived from the bark of Raputia heptaphylla (Pittier) using: (1) peritoneal macrophages and (2) Mesocricetus auratus hamsters infected with Leishmania (V.) panamensis and Leishmania (L.) amazonensis. We observed the ability of this seco-limonoid to induce the effective control of the parasite either in vitro [determining an effective concentration 50 (EC50) of 59 µ m at the infection model] and in vivo (inducing clinical improvement or even cure in infected animals treated compared with the groups of animals treated with vehicle solution or meglumine antimoniate).

  8. Structural Necessity of Indole C5-O-Substitution of seco-Duocarmycin Analogs for Their Cytotoxic Activity

    Directory of Open Access Journals (Sweden)

    Taeyoung Choi

    2010-11-01

    Full Text Available A series of racemic indole C5-O-substituted seco-cyclopropylindole (seco-CI compounds 1-5 were prepared by coupling in the presence of EDCI of 1-(tert-butyloxycarbonyl-3-(chloromethylindoline (seg-A with 5-hydroxy-, 5-O-methylsulfonyl, 5-O-aminosulfonyl, 5-O-(N,N-dimethylaminosulfonyl- and 5-O-benzyl-1H-indole-2-carboxylic acid as seg-B. Compounds 1-5 were tested for cytotoxic activity against four human cancer cell lines (COLO 205, SK-MEL-2, A549, and JEG-3 using a MTT assay. Compounds 2 and 3 with small sized sulfonyl substituents like 5-O-methylsulfonyl and 5-O-aminosulfonyl exhibit a similar level of activity as doxorubicin against all cell lines tested.

  9. Estudio estructural en instalaciones de bomba de calor : Structural study of heat pump´s installations

    Directory of Open Access Journals (Sweden)

    Oscar M. Cruz Fonticiella

    2013-06-01

    Full Text Available Se investigan las irreversibilidades de una bomba de calor, con análisis exergéticos y estructurales. Se utilizó una instalación experimental de una bomba de calor lográndose datos y cálculos de la eficiencia de la compresión, temperaturas medias de los focos caliente y frío del ciclo, diferencia de temperatura a la salida del condensador, media logarítmica del evaporador, caídas de presiones del condensador y el evaporador y un análisis exergético y estructural con las propiedades termodinámicas en los puntos clave del ciclo, coeficiente de comportamiento del ciclo, balances de masas, energías y entropía, entropía generada en cada componente, balance de exergía con las irreversibilidades en cada componente, eficiencia exergética, defecto de eficiencia y coeficientes de vínculos estructurales Se exploraron las potencialidades de mejora de cada componente para una posterior optimización termoeconómica.The irreversibility of a heat pump with exergy and structural analysis is investigated. An experimental installation of a heat pump and calculations achieving data compression efficiency, the average temperature of hot and cold spots in the cycle was used, The temperature difference output condenser, log mean evaporator , pressures drops condenser and evaporator and structural exergy analysis and thermodynamic properties at key points of the cycle, the cycle coefficient of performance, mass balances, energy and entropy, entropy generated in each component, the availability balance irreversibilities in each component , exergetic efficiency, default coefficients efficiency and structural links were obtained. The potential for improvement for each component for further thermoeconomic optimization were explored

  10. Estudio estructural en instalaciones de bomba de calor; Structural study of heat pump´s installations

    Directory of Open Access Journals (Sweden)

    Oscar M. Cruz Fonticiella

    2013-06-01

    Full Text Available Se investigan las irreversibilidades de una bomba de calor, con análisis exergéticos y estructurales. Se utilizó una instalación experimental de una bomba de calor lográndose datos y cálculos de la eficiencia de la compresión, temperaturas medias de los focos caliente y frío del ciclo, diferencia de temperatura a la salida del condensador, media logarítmica del evaporador, caídas de presiones del condensador y el evaporador y un análisis exergético y estructural con las propiedades termodinámicas en los puntos clave del ciclo, coeficiente de comportamiento del ciclo, balances de masas, energías y entropía, entropía generada en cada componente, balance de exergía con las irreversibilidades en cada componente, eficiencia exergética, defecto de eficiencia y coeficientes de vínculos estructurales Se exploraron las potencialidades de mejora de cada componente para una posterior optimización termoeconómica.  The irreversibility of a heat pump with exergy and structural analysis is investigated. An experimental installation of a heat pump and calculations achieving data compression efficiency, the average temperature of hot and cold spots in the cycle was used, The temperature difference output condenser, log mean evaporator , pressures drops condenser and evaporator and structural exergy analysis and thermodynamic properties at key points of the cycle, the cycle coefficient of performance, mass balances, energy and entropy, entropy generated in each component, the availability balance irreversibilities in each component , exergetic efficiency, default coefficients efficiency and structural links were obtained. The potential for improvement for each component for further thermoeconomic optimization were explored.

  11. Uso y verificación con indicadores biológicos en esterilizadores de cirujanos dentistas de San Luis Potosí, México Verification and utilization of sterilizing equipment by dentists in San Luis Potosi, Mexico

    Directory of Open Access Journals (Sweden)

    Nuria Patiño-Marín

    2001-10-01

    Full Text Available Objetivo. Conocer el uso y verificar los ciclos de esterilización con indicadores biológicos en los equipos utilizados por cirujanos dentistas de la Facultad de Estomatología de la Universidad Autónoma de San Luis Potosí (UASLP y del Colegio Dental Potosino. Material y métodos. Estudio transversal hecho en 1999-2000. El 65% (n=130 de los odontólogos participaron con un esterilizador, la verificación se realizó por indicadores que contenían esporas de Bacillus subtilis y de Bacillus stearothermophilus. Resultados. Participaron 30 autoclaves y 100 esterilizadores de calor seco, 23 de ellos (17.7% presentaron crecimiento bacteriano; el 16.1% (n=21 de los participantes utilizan los indicadores biológicos como verificador. Los dos métodos de esterilización presentaron crecimiento bacteriano con frecuencias similares (p=>0.66. Conclusiones. Pocos cirujanos dentistas verifican su esterilizador con indicadores biológicos en los equipos que presentaron crecimiento bacteriano, sus fallas se encontraron en el proceso de esterilización. El texto completo en inglés de este artículo está disponible en: http://www.insp.mx/salud/index.htmlObjective. To assess the utilization of sterilizing equipment used by dentists, and verification of sterilization using biological indicators. Material and methods. A cross-sectional study was conducted in 1999-2000, among 130 (65% dentists having sterilizing equipment, at Facultad de Estomatología, Universidad Autónoma de San Luis Potosí and Colegio Dental Potosino. Biological indicators for sterilization containing Bacillus subtilis and Bacillus stearothermophilus were used. Results. Thirty autoclaves and 100 dry-heat sterilizers were evaluated: 23 (17.7% of them showed bacterial growth. Twenty-one (16.1% dentists already were using biological indicators to verify their sterilizing equipment. Both sterilization methods were found to allow bacterial growth with similar frequencies (p=>0.66. Conclusions

  12. Material-based figure of merit for caloric materials

    Science.gov (United States)

    Griffith, L. D.; Mudryk, Y.; Slaughter, J.; Pecharsky, V. K.

    2018-01-01

    The efficient use of reversible thermal effects in magnetocaloric, electrocaloric, and elastocaloric materials is a promising avenue that can lead to a substantially increased efficiency of refrigeration and heat pumping devices, most importantly, those used in household and commercial cooling applications near ambient temperature. A proliferation in caloric material research has resulted in a wide array of materials where only the isothermal change in entropy in response to a handful of different field strengths over a limited range of temperatures has been evaluated and reported. Given the abundance of such data, there is a clear need for a simple and reliable figure of merit enabling fast screening and down-selection to justify further detailed characterization of those material systems that hold the greatest promise. Based on the analysis of several well-known materials that exhibit vastly different magnetocaloric effects, the Temperature averaged Entropy Change is introduced as a suitable early indicator of the material's utility for magnetocaloric cooling applications, and its adoption by the caloric community is recommended.

  13. High monetary reward rates and caloric rewards decrease temporal persistence.

    Science.gov (United States)

    Fung, Bowen J; Bode, Stefan; Murawski, Carsten

    2017-02-22

    Temporal persistence refers to an individual's capacity to wait for future rewards, while forgoing possible alternatives. This requires a trade-off between the potential value of delayed rewards and opportunity costs, and is relevant to many real-world decisions, such as dieting. Theoretical models have previously suggested that high monetary reward rates, or positive energy balance, may result in decreased temporal persistence. In our study, 50 fasted participants engaged in a temporal persistence task, incentivised with monetary rewards. In alternating blocks of this task, rewards were delivered at delays drawn randomly from distributions with either a lower or higher maximum reward rate. During some blocks participants received either a caloric drink or water. We used survival analysis to estimate participants' probability of quitting conditional on the delay distribution and the consumed liquid. Participants had a higher probability of quitting in blocks with the higher reward rate. Furthermore, participants who consumed the caloric drink had a higher probability of quitting than those who consumed water. Our results support the predictions from the theoretical models, and importantly, suggest that both higher monetary reward rates and physiologically relevant rewards can decrease temporal persistence, which is a crucial determinant for survival in many species. © 2017 The Authors.

  14. Role of sleep timing in caloric intake and BMI.

    Science.gov (United States)

    Baron, Kelly G; Reid, Kathryn J; Kern, Andrew S; Zee, Phyllis C

    2011-07-01

    Sleep duration has been linked to obesity and there is also an emerging literature in animals demonstrating a relationship between the timing of feeding and weight regulation. However, there is a paucity of research evaluating timing of sleep and feeding on weight regulation in humans. The goal of this study was to evaluate the role of sleep timing in dietary patterns and BMI. Participants included 52 (25 females) volunteers who completed 7 days of wrist actigraphy and food logs. Fifty-six percent were "normal sleepers" (midpoint of sleep ≥5:30 AM). Late sleepers had shorter sleep duration, later sleep onset and sleep offset and meal times. Late sleepers consumed more calories at dinner and after 8:00 PM, had higher fast food, full-calorie soda and lower fruit and vegetable consumption. Higher BMI was associated with shorter sleep duration, later sleep timing, caloric consumption after 8:00 PM, and fast food meals. In multivariate models, sleep timing was independently associated with calories consumed after 8:00 PM and fruit and vegetable consumption but did not predict BMI after controlling for sleep duration. Calories consumed after 8:00 PM predicted BMI after controlling for sleep timing and duration. These findings indicate that caloric intake after 8:00 PM may increase the risk of obesity, independent of sleep timing and duration. Future studies should investigate the biological and social mechanisms linking timing of sleep and feeding in order to develop novel time-based interventions for weight management.

  15. Vegetation and climate history from Laguna de Río Seco, Sierra Nevada, southern Spain

    Science.gov (United States)

    Anderson, R. S.; Jimenez-Moreno, G.

    2010-12-01

    The largest mountain range in southern Spain - the Sierra Nevada - is an immense landscape with a rich biological and cultural heritage. Rising to 3,479 m at the summit of Mulhacén, the range was extensively glaciated during the late Pleistocene. Subsequent melting of cirque glaciers allowed formation of numerous small lakes and wetlands. One south-facing basin contains Laguna de Río Seco, a small lake at ca. 3020 m elevation, presently above potential treeline. Pollen analysis of sediment cores documents over 11,000 calendar years of vegetation change there. The early record, to ca. 5,700 cal yr BP, is dominated by pine pollen, with birch, deciduous oak, and grass, with an understory of shrubs types. Pine trees probably never grew at the elevation of the lake, but aquatic microfossils indicate lake levels were highest prior to ca. 7,800 cal yr BP, perhaps as a result of heavy winter precipitation, and early Holocene expansion of the ITCZ. Drier conditions commenced by 5,700 cal yr BP, shown by declines in wetland pollen, and increases in high elevation steppe shrubs more common today (juniper, sage, and others). The local and regional impact of humans increased substantially after ca. 2700 years ago, with the regional loss of pine forest or woodland, increases in pollen and spore types associated with pasturing, and olive cultivation at lower elevations.

  16. Modelo matemático para la descripción de la transferencia de calor para tierra vertida

    Directory of Open Access Journals (Sweden)

    Edgardo Jonathan Suárez-Domínguez

    2014-01-01

    Full Text Available La arquitectura de tierra implica procesos constructivos sustentables ya que utiliza materiales vernáculos duraderos cuyos residuos son de bajo impacto al ambiente. La tierra vertida es una técnica a partir de la cual pueden tenerse muros resistentes dentro de la edificación de viviendas pero cuyas propiedades han sido poco evaluadas y representadas a partir de modelos. La transferencia de calor es una de las características más importantes cuando se edifica en zonas calurosas pues implica ciertos niveles de confort para los usuarios. El presente trabajo propone un modelo para determinar la difusividad térmica de tierra vertida con uso potencial para otras determinaciones a diversas temperaturas, algunas implicaciones también son presentadas. Se encontró que el coeficiente de difusividad térmica de muestras de tierra vertida fue de   4.319  10 8 m 2 s 1 , mientras que su calor específico es de 1.1030 kJkg-1K 1 .

  17. Efecto de la inoculación con bacterias rizosféricas y Trichoderma en trigo (Triticum aestivum L.

    Directory of Open Access Journals (Sweden)

    C. J. Bécquer

    Full Text Available Se realizó un experimento en invernadero para evaluar en trigo el efecto de la inoculación con las rizobacterias Sinorhizobium meliloti, Azospirillum zeae y Azospirillum canadense, y con el hongo Trichoderma harzianum. El diseño experimental fue completamente aleatorizado, con cuatro réplicas y cinco plantas por tratamiento. Se utilizó un tratamiento fertilizado con NH4NO3 (150 ppm/kg de suelo, un control absoluto y 13 tratamientos inoculados. Se evaluó el peso seco aéreo, el peso seco radical, la longitud del tallo, la germinación y el contenido de clorofila foliar. La aplicación de Trichoderma por separado tuvo un efecto positivo en la longitud del tallo (5,58 cm; pero su presencia directa en algunas combinaciones con las bacterias rizosféricas no fue positiva ni mostró resultados uniformes en las variables en el momento de la siembra, o posterior a esta. Sin embargo, se destacó el tratamiento Trichoderma + NRG34-DS2 5d en el peso seco radical (0,45 g/planta y en el peso seco aéreo (0,58 g/planta; así como el tratamiento A2-N7, en el contenido de clorofila (40,35 spads/planta y la longitud del tallo (5,50 cm. Se concluye que la aplicación simple de Trichoderma no ejerció un efecto positivo en la mayoría de las variables ni los tratamientos influyeron positivamente en la germinación. Se recomienda evaluar Trichoderma + NRG34-DS2 5d y A2-N7 en experimentos de campo.

  18. Transferencia de calor en la colada continua de aceros. II parte. Enfriamiento secundario

    Directory of Open Access Journals (Sweden)

    Cicutti, C.

    1997-12-01

    Full Text Available Once the strand leaves the mold, the solidification of steel progresses due to the heat extracted in the secondary cooling zone of the continuous casting machine. In this zone, heat is extracted mainly by: the incidence of water from sprays, radiation to surroundings contact with rolls and run out water accumulated between rolls and strand. In this work, all these mechanisms are evaluated and, when it is possible, they are quantified. Methods which are usually employed to measure solidification profiles in the continuous casting machine are also reviewed. Finally, the incidence of secondary cooling on the quality of cast products is discussed.

    La solidificación del acero iniciada en el molde continúa en la zona de enfriamiento secundario de la máquina donde el calor es extraído, principalmente por la incidencia del agua de los rociadores, la radiación al medio ambiente, el contacto con los rodillos y el agua acumulada en ellos. En este trabajo se revisa cada uno de estos mecanismos determinando, en los casos en que es posible, valores cuantitativos de los mismos. Además, se analizan los distintos métodos empleados para medir el avance del espesor solidificado en la máquina de colada continua. Por último, se discute la incidencia del enfriamiento secundario en la calidad final de los productos colados.

  19. Sensitivity of caloric test and video head impulse as screening test for chronic vestibular complaints

    Science.gov (United States)

    Mezzalira, Raquel; Bittar, Roseli Saraiva Moreira; do Carmo Bilécki-Stipsky, Marcia Maria; Brugnera, Cibele; Grasel, Signe Schuster

    2017-01-01

    OBJECTIVE: This study compared the results of the caloric test with those of the video head impulse test obtained during the same session and evaluated whether the former can be used to screen for non-acute vestibular dysfunction. METHODS: A total of 157 participants complaining of dizziness with vestibular characteristics of varying durations and clinical courses completed the caloric test and video head impulse test. RESULTS: Significantly more caloric test results than video head impulse test results were abnormal. CONCLUSIONS: The results of the caloric test and video head impulse test are distinct but complement each other. Within our sample, the caloric test was more sensitive for vestibular dysfunction. Therefore, the video head impulse test is not a suitable screening tool of the vestibular system in patients with chronic complaints. PMID:28954005

  20. Fugas de calor y aprovechamiento de efluentes en la optimización de ciclos Brayton totalmente irreversibles

    National Research Council Canada - National Science Library

    Herrera, C. A; Rosillo, M.E; Castaño

    2008-01-01

    ... (maquinas irreversibles, flujos disipativos, consumo de potencia en todo trasiego de fluídos, transmisiones de calor a gradientes de temperatura finitos, fugas de calor, desaprovechamiento de efluentes, restricciones en caídas de presión...

  1. Modelación y simulación de disipadores de calor para procesadores de computadora en COMSOL Multiphysics Modeling and simulation of heat sinks for computer processors in COMSOL Multiphysics

    Directory of Open Access Journals (Sweden)

    Sulin Garro Acón

    2012-11-01

    Full Text Available En este estudio se analizó la transferencia de calor en tres disipadores de calor utilizados para enfriar los procesadores de computadoras de escritorio. El objetivo de estos disipadores es evitar el sobrecalentamiento de la unidad de procesamiento y la consecuente reducción de la vida útil del computador. Los disipadores de calor se modelaron usando COMSOL Multiphysics con las dimensiones reales de los dispositivos y la generación de calor se modeló con una fuente puntual. Luego se modificaron los diseños de los disipadores para lograr una temperatura más baja en la zona más caliente del procesador. El resultado fue una reducción en la temperatura en el rango de 5-78 grados Kelvin, al rediseñarse el disipador de calor con variaciones feasibles como la reducción del grosor de las placas de intercambio de calor y el aumento de su número. Esto demuestra la posibilidad de desarrollar diseños optimizados para disipadores de calor que no requieran más materiales sino una mejor ingeniería. El trabajo se inició como parte del curso CM-4101 Modelización y Simulación.In this study, the heat transfer of three desktop- computer heat sinks was analyzed. The objective of using these heat sinks is to avoid overheating of the computer’s processing unit and in turn reduce the corresponding loss in the unit’s service time. The heat sinks were modeled using COMSOL Multiphysics with the actual dimensions of the devices, and heat generation was modeled with a point source. In the next step, the heat sink designs were modified to achieve a lower temperature in the higher temperature location on the heat sink. The results were temperature reductions in the range of 5-78 degrees Kelvin, by making feasible variations in design such as reducing the thickness of the heat exchanger fins and increasing their number. This paper demonstrates that there is room to develop improved designs that do not require more materials but rather a better engineering

  2. Caloric requirements in patients with inflammatory bowel disease.

    Science.gov (United States)

    Barot, L R; Rombeau, J L; Feurer, I D; Mullen, J L

    1982-01-01

    Measured resting energy expenditure (REE) was compared to predicted basal energy expenditure (BEE) in 35 consecutive patients with nonseptic inflammatory bowel disease (IBD) and 20 healthy volunteers. Patients with IBD were groups greater or less than 90% ideal body weight (IBW). The BEE in kcal/day was found to be equivalent to the measured REE in both patient groups. It is suggested that the BEE be used to determine caloric requirements in nonseptic patients with inflammatory bowel disease. Patients less than 90% IBW had significantly higher measured energy expenditure (26.4 +/- 1.0) per kg body weight than either controls (21.2 +/- 0.7) or patients greater than or equal to 90% IBW (21.2 +/- 0.8), p less than 0.001. It is suggested that this increased expenditure is due to a combined effect of weight loss and intrinsic disease. PMID:7055399

  3. Caloric Restriction Promotes Structural and Metabolic Changes in the Skin

    Directory of Open Access Journals (Sweden)

    Maria Fernanda Forni

    2017-09-01

    Full Text Available Caloric restriction (CR is the most effective intervention known to enhance lifespan, but its effect on the skin is poorly understood. Here, we show that CR mice display fur coat remodeling associated with an expansion of the hair follicle stem cell (HFSC pool. We also find that the dermal adipocyte depot (dWAT is underdeveloped in CR animals. The dermal/vennule annulus vasculature is enlarged, and a vascular endothelial growth factor (VEGF switch and metabolic reprogramming in both the dermis and the epidermis are observed. When the fur coat is removed, CR mice display increased energy expenditure associated with lean weight loss and locomotion impairment. Our findings indicate that CR promotes extensive skin and fur remodeling. These changes are necessary for thermal homeostasis and metabolic fitness under conditions of limited energy intake, suggesting a potential adaptive mechanism.

  4. Caloric restriction and the aging process: a critique.

    Science.gov (United States)

    Sohal, Rajindar S; Forster, Michael J

    2014-08-01

    The main objective of this review is to provide an appraisal of the current status of the relationship between energy intake and the life span of animals. The concept that a reduction in food intake, or caloric restriction (CR), retards the aging process, delays the age-associated decline in physiological fitness, and extends the life span of organisms of diverse phylogenetic groups is one of the leading paradigms in gerontology. However, emerging evidence disputes some of the primary tenets of this conception. One disparity is that the CR-related increase in longevity is not universal and may not even be shared among different strains of the same species. A further misgiving is that the control animals, fed ad libitum (AL), become overweight and prone to early onset of diseases and death, and thus may not be the ideal control animals for studies concerned with comparisons of longevity. Reexamination of body weight and longevity data from a study involving over 60,000 mice and rats, conducted by a National Institute on Aging-sponsored project, suggests that CR-related increase in life span of specific genotypes is directly related to the gain in body weight under the AL feeding regimen. Additionally, CR in mammals and "dietary restriction" in organisms such as Drosophila are dissimilar phenomena, albeit they are often presented to be the very same. The latter involves a reduction in yeast rather than caloric intake, which is inconsistent with the notion of a common, conserved mechanism of CR action in different species. Although specific mechanisms by which CR affects longevity are not well understood, existing evidence supports the view that CR increases the life span of those particular genotypes that develop energy imbalance owing to AL feeding. In such groups, CR lowers body temperature, rate of metabolism, and oxidant production and retards the age-related pro-oxidizing shift in the redox state. Copyright © 2014 The Authors. Published by Elsevier Inc. All

  5. Low Caloric Sweeteners for Diabetes and Obesity Care and Their

    Directory of Open Access Journals (Sweden)

    Mohammad Asif

    2015-10-01

    Full Text Available Diabetes and obesity are two common human disorders that affecting human health and invite various diseases and disorders in normal body functions. These diseases are very common worldwide. Diabetes occurs when high blood sugar levels develop. This happens when body can’t make and use all of the insulin it needs to blood sugar normally to keep blood sugar levels as normal as possible to control diabetes. Diabetic patients will need to follow a diet plan, do exercise and possibly take insulin injections. As part of eating plan, health care provider, and dietitian may ask to limit the amount of carbohydrates eat each day. Low-calorie sweeteners are one easy tool to help for follow eating plan. Obesity is more susceptible and often been associated with frequent ingestion of high energy food in high amount and high intake of sugars such as fermentable sugars such as sucrose, fructose, glucose, and maltose. Both diseases are may be genetically or due to hormonal imbalances. High energy sweeteners may causes caries in the teeth particularly susceptible to the children. Increased calorie intake associated with sugars and carbohydrates, especially when associated with physical inactivity, has been implicated in obesity. Fortunately, low calorie artificial and natural alternatives of sugars have been developed as alternatives to fermentable sugars and have shown promise in these health issues. Although there are only few artificial sweeteners (saccharin, aspartame, acesulfam potassium, sucralose, cyclamate that have been approved as food additives by the Food and Drug Administration and additional other low-caloric sweeteners (sugar alcohols, neotame, stevia, erythritol, xylitol, tagatose that have FDA-generally recognized as safe. Given the health impact of sugars and other carbohydrates, professionals should be aware of the marketed available low caloric sweeteners and both their benefits and potential risks.

  6. Combined Salt and Caloric Restrictions: Potential Adverse Outcomes.

    Science.gov (United States)

    Homma, Tsuyoshi; Homma, Mika; Huang, Yuefei; Mayurasakorn, Korapat; Rodi, Nurul Mahamad; Hamid, Anis Amalina Abdul; Hurwitz, Shelley; Yao, Tham; Adler, Gail K; Pojoga, Luminita H; Williams, Gordon H; Romero, Jose R

    2017-10-11

    We hypothesized that caloric restriction (CR) and salt restriction (ResS) would have similar effects on reducing cardiovascular risk markers and that combining CR and ResS would be synergistic in modulating these markers. To test our hypothesis, rats were randomized into 2 groups: ad libitum liberal salt diet (ad libitum/high-sodium, 1.6% sodium) or ResS diet (ad libitum/ResS, 0.03% sodium). CR was initiated in half of the rats in each group by reducing caloric intake to 60% while maintaining sodium intake constant (CR/high-sodium, 2.7% sodium or CR/ResS, 0.05% sodium) for 4 weeks. CR in rats on a high-sodium diet improved metabolic parameters, renal transforming growth factor-β and collagen-1α1 and increased plasma adiponectin and renal visfatin and NAD+ protein levels. Although CR produced some beneficial cardiovascular effects (increased sodium excretion and reduced blood pressure), it also was associated with potentially adverse cardiovascular effects. Adrenal zona glomerulosa cell responsiveness and aldosterone levels and activation were inappropriately increased for the volume state of the rodent. Like CR on HS, CR on a ResS diet also produced relative increased zona glomerulosa responsiveness and an increased blood pressure with no improvement in metabolic parameters. These results suggest that combining CR and ResS may decrease the beneficial effects of each alone. Furthermore, CR, regardless of dietary salt intake, inappropriately activates aldosterone production. Thus, caution should be used in combining ResS and CR because the combination may lead to increased cardiovascular risk. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

  7. Modelamiento y simulación del efecto de la entrada de calor en la penetración de una junta soldada

    Directory of Open Access Journals (Sweden)

    Lina Gómez

    2003-01-01

    Full Text Available En esta investigación se realizó el simulador SimVol, en el cual se experimentó con el fin de encontrar una relación entre la entrada de calor y la penetración de la junta soldada. SimVol se basó en un modelo en 2D, que describe el flujo de calor y el flujo de metal líquido en el charco de una soldadura realizada con el proceso GTAW (Gas Tungsten Arc Welding. En el modelo matemático se incluyen las ecuaciones de Navier-Stokes y la ecuación de energía, las cuales constituyen un sistema de ecuaciones diferenciales parciales de segundo orden, no-lineales, no homogéneas y transitorias. El modelo numérico se desarrolla en Volúmenes Finitos en un esquema totalmente implícito, con malla regular y escalonada; además, debido al desconocimiento del campo de presión es necesario utilizar el algoritmo SIMPLE (Semi-Implicit Method for Pressure-Linked Equations. La investigación también incluye una serie de experimentos que permitieron validar el modelo planteados.

  8. Heat transfer in simple houses; Transferencia de calor en casas habitacion

    Energy Technology Data Exchange (ETDEWEB)

    Porta, Miguel Angel; Rubio, Eduardo; Fernandez, Jose Luis [Centro de Investigaciones Biologicas del Noroeste, Baja California Sur, (Mexico); Gomez Munoz, Victor [Centro Interdiciplinario de Ciencias Marinas, Baja California Sur (Mexico)

    2000-07-01

    habitacion bajo distintas combinaciones de factores geometricos, incluyendo la orientacion de la vivienda, los parteluces y otros protectores de la fachada, los materiales y los metodos constructivos. El articulo presenta el balance energetico del sistema, que aqui se representa mediante tres ecuaciones de equilibrio energetico, que describen cada una, la ventana, la obra de mamposteria y el aire interior. La solucion simultanea de las ecuaciones diferenciales se obtiene por el metodo de Kutta, de la que se despejan las temperaturas medias representativas de cada uno de los elementos anteriores, y se calcula el flujo de calor entre ellos a lo largo del dia, asi como los flujos de intercambio con el exterior.

  9. Tolerancia al calor y humedad atmosférica de diferentes grupos raciales de ganado bovino

    Directory of Open Access Journals (Sweden)

    Ariel Guillén T

    2011-04-01

    Full Text Available Objetivo. Comparar algunas respuestas fisiológicas al calor y humedad atmosférica entre bovinos Chinampos (Bos taurus; Ch, ½ Charolais ½ Brahman (CB, Holstein (H y Jersey (J. Materiales y métodos. Se realizó un estudio en La Paz, México. Se utilizaron 12 vacas H, 10 J, 15 Ch y 8 CB. Durante el verano se midieron cada semana (a las 0600 y 1600 horas la frecuencia respiratoria (FR y temperatura rectal (TR. Se registraron las variables climáticas para calcular el índice de temperatura-humedad (ITH. Resultados. Durante todo el verano, la FR en los cuatro grupos estuvo por encima de los valores fisiológicos para el ganado bovino, siendo superior en H y J que en Ch y CB (p<0.01. En todos los grupos, la TR estuvo dentro de los límites fisiológicos de la especie estudiada. El grupo racial más afectado fue H (p<0.05. Cuando las constantes fisiológicas fueron analizadas dentro de cada una de tres categorías de ITH (<72, ≥72<78, y ≥78, las vacas H y J mostraron FR superior a las Ch y CB (p<0.01. La TR aumentó conforme se elevó el ITH siendo más marcado en J y H. El incremento de la FR entre la mañana y la tarde de cada día de medición fue mayor en H y J que en Ch y CB (p<0.05. La TR se incrementó más en H que en Ch (p<0.05. Conclusiones. Los grupos raciales más tolerantes al estrés por calor, determinado con base en FR y TR fueron Ch y CB.

  10. Modelado de la transferencia de calor e índices de calidad durante el escaldado convencional y asistido por ultrasonidos de champiñones.

    OpenAIRE

    LESPINARD, ALEJANDRO; Bon Corbín, José; Carcel Carrión, Juan Andrés; Benedito Fort, José Javier; Mascheroni, Rodolfo Horacio

    2013-01-01

    En la industria de los alimentos, el uso de ultrasonidos (US) en combinación con procesos convencionales ofrece nuevas posibilidades para la mejora de los procesos de alimentos, que van desde el ahorro de energía a aumentos en el rendimiento del proceso o la calidad del producto; en este sentido ha demostrado ser una tecnología emergente que permite mejorar la transferencia de calor y materia. No obstante, aún es necesario realizar estudios concretos para los diferentes procesos y/o productos...

  11. El fenómeno de la isla de calor en dos ciudades turísticas. Los casos de Ibiza y Lloret de Mar

    OpenAIRE

    Serra Pardo, Juan

    2016-01-01

    [spa] El estudio del clima urbano ha permitido analizar la modificación que las ciudades ejercen sobre el clima regional a escala local, especialmente la alteración térmica que supone. Esta alteración, conocida con el nombre de isla de calor urbana (ICU), es el elemento más significativo y mejor conocido del clima urbano. De este modo, desde diferentes disciplinas se ha estudiado el fenómeno, estableciendo sus características, causas, impactos y consecuencias, en primer lugar, para luego desa...

  12. Study of the internal heat transfer of the water flow in nucleate boiling; Estudio de la transferencia de calor del flujo interno de agua en ebullicion nucleada

    Energy Technology Data Exchange (ETDEWEB)

    Payan Rodriguez, Luis Alfredo

    2003-09-01

    propuestos se utilizaron en un caso de estudio derivado de un problema real en una planta termoelectrica, donde se requeria simular el proceso de ebullicion en los tubos del hogar del generador de vapor para determinar las causas de las fallas que ocurrieron en un numero considerable de tubos. Con los resultados obtenidos se logro establecer que las fallas en los tubos del generador de vapor analizado se debieron a que la relacion de transferencia de calor en el hogar alcanzo valores criticos que provocaron la desviacion de la ebullicion nucleada a ebullicion pelicular, ocasionando la disminucion del coeficiente de transferencia de calor con el consecuente incremento subito en la temperatura de la pared del tubo.

  13. Análisis exergético comparativo entre intercambiadores de calor // A comparative exergetic analysis of compact heat exchangers

    Directory of Open Access Journals (Sweden)

    Rubén Borrajo-Pérez

    2011-08-01

    Full Text Available Los intercambiadores de calor son equipos de importancia primordial en la industria y enaplicaciones domésticas en general. El trabajo está relacionado con el area de la intensificacion de latransferencia de calor en intercambiadores de calor compactos y la comparación entre diferentestipos de superficies intensificadas. La comparación es realizada a partir del análisis de la exergíadestruída por la superfície de intercambio como resultado de las perdidas por fricción y delintercambio térmico entre cuerpos con diferencia finita de temperaturas. El análisis de Segunda Leyde la Termodinámica permite identificar en que superfície de intercambio se genera mas entropía.Como resultado fundamental se obtiene la dependencia entre la exergía destruída y elespaciamiento transversal para una superfície formada por una fila de tubos elipticos a diferentesvalores del numero de Reynolds. Se identifica al intercambio térmico como la de mayor aporte a laentropía generada. Finalmente se demuestra la viabilidad de la intensificación de la transferencia decalor empleando generadores de vórtices en intercambiadores de calor.Palabras claves: generadores de vórtices, intecambiadores de calor compactos, tubos elípticos, exergía.__________________________________________________________________AbstractThe heat exchangers are important devices in both industry and household applications. This work isabout heat transfer enhancement in heat exchangers surface. Many heat transfer enhancementtechniques can be applied and then a comparative tool is needed to evaluate its performance.Thermodynamics is one of these tools and the exergetic analysis can be applied to heat exchangersurfaces. The exergy destroyed because both of thermal exchange between bodies with differenttemperatures and destroyed by friction drag is calculated. These results are used to compare heatexchanger surfaces. Heat exchanger surfaces in smooth configuration and the same surfaces

  14. Coeficientes de transferencia de calor experimental para el enfriamiento de licor en intercambiadores de placas//Experimental heat transfer coefficients for the liquor cooling in plate heat exchanger

    Directory of Open Access Journals (Sweden)

    Enrique Torres‐Tamayo

    2014-01-01

    Full Text Available La pérdida de eficiencia del proceso de enfriamiento del licor amoniacal, mediante el uso de intercambiadores de calor de placas, está asociada a imprecisiones en la estimación de los coeficientes de transferencia de calor y la acumulación de incrustaciones en la superficie de intercambio. El objetivo de la investigación es determinar los coeficientes de transferencia de calor y la influencia de lasincrustaciones en la pérdida de eficiencia de la instalación. Mediante un procedimiento iterativo se estableció la ecuación del número de Nusselt y su relación con el número de Reynolds y Prandtl. Se utilizó un diseño experimental multifactorial. Los resultados predicen el conocimiento de los coeficientespara el cálculo del número de Nusselt en ambos fluidos. Los valores de los coeficientes del licor amoniacal son inferiores, ello se debe a la presencia de componentes gaseosos. La ecuación obtenida muestra correspondencia con el modelo de Buonapane, el error comparativo es del 3,55 %.Palabras claves: intercambiador de calor de placas, coeficientes de transferencia de calor, eficiencia térmica.______________________________________________________________________________AbstractThe loss of efficiency of the ammonia liquor cooling process, by means of the plate heat exchanger, is associated to the incorrect estimate of the heat transfer coefficients and the accumulation of inlays in the exchange surface. The objective of the investigation is to determine the transfer coefficients and the influence of the inlays in the efficiency loss of the installation. By means of an iterative procedure was obtained the Nusselt number equation and the relationship with the Reynolds and Prandtl number, for it was used it a design experimental multifactorial. The results predict the knowledge of the coefficients forthe calculation of the Nusselt number for both fluids. The ammonia liquor coefficients values are inferior, due to the presence of gassy

  15. Evaluación nutricional de arbóreas y arbustivas de bosque muy seco tropical (bms- T en producción bovina

    Directory of Open Access Journals (Sweden)

    Edmundo Apráez

    2017-06-01

    Full Text Available Se determinó la calidad nutricional de las arbóreas Payandé (Pithecellobium lanceolatum MART., Guácimo (Guazuma ulmifolia LAM., Caña fístula (Cassia fistula L., Chiminango (Pithecellobium dulce MART. y Samán (Samanea saman JACQ. en zona de bosque muy seco tropical (bms-T del Valle del Patía y el efecto como suplemento en la alimentación de bovinos mestizos tipo cebú. Se evaluaron seis tratamientos: T0 (100% pastoreo, T1(90% pastoreo +10% P. lanceolatum; T2 (90% pastoreo +10% P.dulce; T3 (90% pastoreo +10% S.saman; T4 (90% pastoreo +10% C. fistula y T5(90% pastoreo +10% G. ulmifolia, distribuidos en un diseño de Bloques Completos al Azar. Se valoró la fenología, composición nutricional y metabolitos secundarios de las arbóreas. Los mayores contenidos de Materia Seca (47,1%, Proteína Cruda (23,5%, Fibra Detergente Neutro (58% y Energía Bruta (523 Kcal/100g los presentó P. saman. La FDA fue superior (p<0,05 en P. lanceolatum y G. ulmifolia con 39,5%. C. fistula y P. saman presentaron los menores niveles de metabolitos secundarios. Las saponinas se detectaron en P. lanceolatum. P. dulce. P. lanceolatum y G. ulmifolia. Estas reportaron bajos niveles de esteroides y ninguna de las especies presentó alcaloides. El consumo de C. fistula y G. ulmifolia fue bajo, solo 10g/día, las demás especies se consumieron en cantidades superiores a 100g/día. La mayor ganancia de peso se obtuvo con P. saman (560g/día, hubo pérdida de peso con C. fistula (-20g/día. En época lluviosa los pesos más altos fueron: C. fistula (1,7kg, P. saman y G.ulmifolia (1,36kg, P. lanceolatum (0,9kg y P. dulce (0,36kg.

  16. REPTILES DEL BOSQUE SECO ESTACIONAL EN EL CARIBE COLOMBIANO: DISTRIBUCIÓN DE LOS HÁBITATS Y DEL RECURSO ALIMENTARIO

    Directory of Open Access Journals (Sweden)

    Luis Eduardo ROJAS MURCIA

    2016-01-01

    Full Text Available Con el fin de caracterizar la distribución horizontal (repartición de los hábitats y la utilización del recurso alimentario (tipo y tamaño de las presas del ensamblaje de reptiles del bosque seco estacional al norte de la región Caribe de Colombia, en el departamento del Cesar, se realizaron cinco salidas de campo con una duración de doce días cada una. Los muestreos se realizaron en jornadas diurnas y nocturnas, en un diseño de transectos replicados a lo largo de diferentes hábitats que incluyeron: pastizales, bordes e interiores de bosque. Se realizaron análisis descriptivos de uso de hábitat en un perfil de vegetación por cada época climática y análisis de amplitud y sobreposición de nicho. Se registraron 38 especies de 14 familias del orden Squamata . Las especies se distribuyeron de manera homogénea entre zonas abiertas y boscosas. Se encontraron registros de 31 categorías de presa en 109 estómagos de seis especies de serpientes (61 estómagos y siete de lagartos (48 estómagos con un porcentaje de estómagos vacíos de 38 %. Las presas de mayor importancia para los lagartos fueron Coleoptera y Araneae , y para las serpientes fueron los anfibios. La mayoría de las especies presentaron un amplio espectro de dieta y entre especies similares, como entre Anolis auratus y A. gaigei , se presentó uso de recursos similares. En síntesis, el ensamblaje de reptiles presentó una distribución homogénea en los hábitats evaluados (áreas abiertas y boscosas y el recurso alimentario fue variado entre las diferentes especies; la estacionalidad de la zona presenta un papel fundamental en la estructura del ensamblaje de reptiles, presentándose menos abundancia durante la época seca, tanto en las áreas abiertas como en las boscosas.

  17. Inhaladores de polvo seco para el tratamiento de las enfermedades respiratorias: Parte I Dry powder inhalers for the treatment of respiratory diseases: Part I

    Directory of Open Access Journals (Sweden)

    Adriana Muñoz Cernada

    2006-08-01

    Full Text Available Se presenta una revisión acerca de la tecnología de los inhaladores de polvo seco (IPS empleados para el tratamiento de las enfermedades respiratorias entre las que se destaca el asma bronquial y la enfermedad pulmonar obstructiva crónica (EPOC. Los IPS comenzaron su desarrollo en la década de los 70 y se han reactualizado en años recientes como una alternativa de sustitución de los inhaladores de dosis metrada con clorofluocarbono (CFC. Se describen los antecedentes de esta tecnología, se mencionan las características físico-químicas principales de este tipo de formulación, así como los factores que influyen en la desagregación y dispersión de los polvos. Por último, se menciona la técnica empleada actualmente en el desarrollo de un nuevo prototipo de IPS que permite optimizar los mecanismos de fluidización para lograr una dosificación altamente reproducibleA review of the dry powder inhalers (DPI technology used to treat respiratory diseases, such as bronchial asthma and chronic obstructive pulmonary disease (COPD, was made. The DPIs began to be developed in the 70's and they have been reupdated recently as a replacement alternative of metered-dose inhalers with chlorofluorocarbon (CFC. The history of this technology is dealt with, the main physicochemical characteristics of this type of formulation are described, and the factors influencing on the disaggregation and dispersion of the powders are mentioned. Finally, the technique used at present in the development of a new prototype of DPI that allows to optimize the fluidization mechanisms to attain a highly reproducible dosage is approached

  18. Eficacia de la esterilización de instrumental endodóncico estandarizado por diversos métodos

    OpenAIRE

    Pumarola Suñé, José; Espías Gómez, Ángel F. (Ángel Fortunato); Canalda Sahli, Carlos; Brau Aguadé, Esteban

    1990-01-01

    En este estudio se han determinado los valores mínimos de la relación tiempo-temperatura eficaces para la esterilización de limas k contaminadas por Bacillus subtilis, por diferentes métodos de esterilización. La esterilización con calor seco y óxido de etileno fue absoluta, por el contrario se observaron resultados diversos con calor húmedo.

  19. LA CÁTEDRA DE ESTUDIOS AFROCOLOMBIANOS: UNA POSIBILIDAD DE DESCOLONIZACIÓN DEL LENGUAJE EN EL CARIBE SECO COLOMBIANO

    OpenAIRE

    Ernell Villa; Wilmer Villa

    2011-01-01

    En este trabajo se hace un reconocimiento a las apuestas que se desarrollan en una zona silenciada dentro de una región excluida. El Caribe seco es un lugar de la geografía colombiana donde las comunidades negras vienen desarrollando diferentes acciones para afirmar la vida desde la descolonización. El texto aborda el sentido pedagógico de la Cátedra de Estudios Afrocolombianos, a partir de prácticas culturales devaluadas. Inicialmente se hace una contextualización histórica, territorial, jur...

  20. Postglacial history of alpine vegetation, fire, and climate from Laguna de Río Seco, Sierra Nevada, southern Spain

    Science.gov (United States)

    Anderson, R. S.; Jiménez-Moreno, G.; Carrión, J. S.; Pérez-Martínez, C.

    2011-06-01

    The Sierra Nevada of southern Spain is a landscape with a rich biological and cultural heritage. The range was extensively glaciated during the late Pleistocene. However, the postglacial paleoecologic history of the highest range in southern Europe is nearly completely unknown. Here we use sediments from a small lake above present treeline - Laguna de Río Seco at 3020 m elevation - in a paleoecological study documenting over 11,500 calendar years of vegetation, fire and climate change, addressing ecological and paleoclimatic issues unique to this area through comparison with regional paleoecological sequences. The early record is dominated by Pinus pollen, with Betula, deciduous Quercus, and grasses, with an understory of shrubs. It is unlikely that pine trees grew around the lake, and fire was relatively unimportant at this site during this period. Aquatic microfossils indicate that the wettest conditions and highest lake levels at Laguna de Río Seco occurred before 7800 cal yr BP. This is in contrast to lower elevation sites, where wettest conditions occurred after ca 7800. Greater differences in early Holocene seasonal insolation may have translated to greater snowpack and subsequently higher lake levels at higher elevations, but not necessarily at lower elevations, where higher evaporation rates prevailed. With declining seasonality after ca 8000 cal yr BP, but continuing summer precipitation, lake levels at the highest elevation site remained high, but lake levels at lower elevation sites increased as evaporation rates declined. Drier conditions commenced regionally after ca 5700 cal yr BP, shown at Laguna de Río Seco by declines in wetland pollen, and increases in high elevation steppe shrubs common today ( Juniperus, Artemisia, and others). The disappearance or decline of mesophytes, such as Betula from ca 4000 cal yr BP is part of a regional depletion in Mediterranean Spain and elsewhere in Europe from the mid to late Holocene. On the other hand

  1. Laboratório caseiro: calorímetro de baixo custo

    OpenAIRE

    Laburú, Carlos Eduardo; UEL - Párana; Rodrigues, Rogério; UEL - Paraná

    1998-01-01

    Este trabalho propõe a construção de um calorímetro de baixo custo, de montagem simples e com materiais facilmente encontrados. Objetiva- se com o calorímetro proposto substituir os normalmente utilizados nos laboratórios de física do secundário. Examina-se a capacidade térmica e o isolamento térmico do calorímetro proposto, comparando-o com um comercial muito utilizado nas escolas.

  2. Prácticas de Física: Calor de fusión

    OpenAIRE

    Beléndez,Augusto; Bernabeu, Guillermo; Vera Guarinos, Jenaro; Pastor Antón, Carlos; Martín García, Agapito

    1988-01-01

    El objetivo de esta práctica de laboratorio es la determinación del calor latente de fusión del hielo mediante el método de las mezclas así como el aprendizaje del manejo del calorímetro como instrumento de trabajo en experiencias térmicas, fundamentalmente de calorimetría. Para desarrollar la experiencia se introduce en un calorímetro una cierta cantidad de líquido a una temperatura superior a la del ambiente y luego añadir una cantidad de hielo a su temperatura de fusión. Es necesario conoc...

  3. Impacto ecológico de los intercambiadores de calor de tubo y coraza

    OpenAIRE

    Reyes–Rodríguez, Maida Bárbara; Moya Rodríguez, Jorge Laureano; Cruz Fonticiella, Oscar Miguel

    2014-01-01

    Los intercambiadores de calor del tipo de coraza y tubo constituyen uno de los equipos más importantes en las plantas de procesos químicos. El diseño de los intercambiadores de calor desde el punto de vista termodinámico se basa en dos aspectos fundamentales, el coeficiente global de transferencia de calor y la caída de presión total. En el año 2007 el Científico chino Guo estableció una nueva propiedad termodinámica denominada “Entransía”, la cual expresa la capacidad de un cuerpo de transfe...

  4. Diseño, Construcción y Calibración de un calorímetro de solución de precisión media

    Directory of Open Access Journals (Sweden)

    Alfredo Gómez O.

    2009-07-01

    Full Text Available Se descriten los criterios de diseño, la construcción y la calibración de un calorímetro isoperit> ólico de solución de precisión media y de bajo costo. Se miden los cambios térmicos mediante un termistor de 15.000 otimios a 293 K, cuya calibración permite encontrar la expresión AT = -52,495 log,o (Rf/Ri para el cambio de temperatura en función de la resistencia, en el rango de trabajo, 297 a 299 K, La sensibilidad termométríca es 0,00158 K/otimio. El error relativo máximo en las medidas calorimétricas con el sistema de calibración benceno-cíclotiexano es de 3%. el de la capacidad calorífica es de 2,74% y el correspondiente a la diferencia de temperatura es de 1,66%, Se encuentran problemas por la gran pendiente de pérdidas de calor, 0,048 K/mln. (valor máximo observado. El coeficiente de transferencia de calor de las paredes del vaso calorimétrico resultó elevado aunque cumple las especificaciones exigidas.

  5. Caloric intake and Alzheimer's disease. Experimental approaches and therapeutic implications.

    Science.gov (United States)

    Pasinetti, Giulio Maria; Zhao, Zhong; Qin, Weiping; Ho, Lap; Shrishailam, Yemul; Macgrogan, Donal; Ressmann, Wendy; Humala, Nelson; Liu, Xunxian; Romero, Carmen; Stetka, Breton; Chen, Linghong; Ksiezak-Reding, Hanna; Wang, Jun

    2007-01-01

    Alzheimer's disease (AD) is a rapidly growing public health concern with potentially devastating effects. Presently, there are no known cures or effective preventive strategies. While genetic factors are relevant in early-onset cases, they appear to play less of a role in late-onset sporadic AD cases, the most common form of AD. Due to the fact that the disease typically strikes very late in life, delaying symptoms could be as good as a cure for many people. For example, it is now widely accepted that if the onset of the disease could be delayed by even 5 years, the incidence could be cut in half. Both clinical and epidemiological evidence suggests that modification of lifestyle factors such as nutrition may prove crucial to AD management given the mounting experimental evidence suggesting that brain cells are remarkably responsive to "what somebody is doing". Among other nongenetic factors influencing AD, recent studies strongly support the evidence that caloric intake may play a role in the relative risk for AD clinical dementia. Indeed, the effect of diet in AD has been an area of research that has produced promising results, at least experimentally. Most importantly, as mechanistic pathways are defined and their biochemical functions scrutinized, the evidence supporting a direct link between nutrition and AD neuropathology continues to grow. Our work, as well as that of others, has recently resulted in the development of experimental dietary regimens that might promote, attenuate or even reverse features of AD. Most remarkably, while we found that high caloric intake based on saturated fat promotes AD type Beta-amyloidosis, conversely we found that dietary restriction based on reduced carbohydrate intake is able to prevent it. This evidence is very exciting and is, in part, consistent with current epidemiological studies suggesting that obesity and diabetes are associated with a >4-fold increased risk of developing AD. The clarification of the mechanisms

  6. Calores de Solución y Propiedades Termodinámicas Relacionadas: Un método Gráfico General de Cálculo

    Directory of Open Access Journals (Sweden)

    Alfredo Gómez O.

    2009-07-01

    Full Text Available Se presenta un método gráfico de cálculo con el cual es posible evaluar a partir de datos de calor de solución. diferentes propiedades termodinámicas de interés tales como: caloresres diferenciales de solución del soluto y del solvente. A HD,P 2 V ^ HOIF.I • calor de solución a dilución infinita A tH°; entalpias molares parciales relativas del soluto y del solvente. Lj y L,. y la entalpia molar aparente relativa, L^. El método está basado en la representación gráfica del calor integral de solución expresado por mol de soluto, A H||,fr.2 en función de la relación entre el número de moles de solvente y soluto, n^/nj. Cuando k>s datos experimentales de calor de solución son tomados hasta alta dilución, puede obtenerse con precisión el vak>r de A H°, con to cual el diagrama propuesto corresponde también a la representación gráfica de(^L2 en función de n^/nj. Se discute el significado f fsk» de las propiedades consideradas así como las relaciones existentes entre ellas. El diagrama propuesto presenta ventajas ya que además de su carácter más general, resulta más preciso y conveniente que k>s métodos particulares comúnmente empleados, especialmente en la evaluación de las propiedades citadas para el caso del soluto en soluciones muy diluidas. de(^L2 en función de n^/nj. Se discute el signifteado f fsk» de las propiedades conskJeradas asi como las relaciones existentes entre ellas. El diagrama propuesto presenta ventajéis ya que además de su caráctermás general, resulta más preciso y conveniente que k>s métodos particulares comúnmente empleados, especialmente en la evaluackin de las propiedades citadas para el caso del soluto en soluctones muy diluidas.

  7. INDEPENDENCIA DE MALLA EN TUBOS TORSIONADOS PARA INTERCAMBIO DE CALOR: CASO DE ESTUDIO

    Directory of Open Access Journals (Sweden)

    Juan Gonzalo Ardila-Marín

    2016-01-01

    Full Text Available La dinámica de fluidos computacional (Computational Fluids Dynamics – CFD ha sido útil para la predicción del desarrollo dinámico y térmico en intercambiadores de calor de tubos curvados y torsionados, tal como lo hizo Záchar en 2010 cuando investigó la doble mejora del curvado y una vena corrugada helicoidal que simulaba la inserción de un resorte al interior del tubo, pero geometrías comerciales como Turbotec® no han sido investigadas. Además, varias herramientas comerciales para la generación de malla están disponibles, sin embargo, el efecto que la calidad y el número de elementos tienen en la solución y el aumento del costo de cómputo, obliga a equilibrar la precisión con los recursos computacionales disponibles. Esta investigación buscó la discretización del volumen de control de intercambiadores mejorados realistas, para su posterior uso en el desarrollo numérico de correlaciones para dimensionamiento y selección. Luego de una evaluación del estado del arte y del desarrollo geométrico de los volúmenes de control con las herramientas CAD SolidEdge® y DesignModeler®, se empleó la herramienta Meshing® de ANSYS Workbench® para el mallado, evaluando los métodos y las configuraciones globales y locales de malla, para su generación y la verificación de métricas; se desarrollaron estudios de independencia de malla para dos geometrías de intercambiadores, evaluando la incidencia de la calidad y el número de elementos en la convergencia del Número de Nusselt, y se validaron con resultados experimentales disponibles en la literatura. Como resultado principal se seleccionaron las mejores mallas para el estudio numérico de cada geometría y se validó la metodología propuesta. Los resultados de simulación son influenciados por la calidad del mallado, entre otros parámetros; todos deben ser evaluados antes de emplear dichos resultados en la toma de decisiones, y es necesario usar resultados experimentales para

  8. Ciliates (Protozoa from dried sediments of a temporary pond from Argentina Ciliados (Protozoa de sedimentos secos de una charca temporaria de la Argentina

    Directory of Open Access Journals (Sweden)

    Gabriela Cristina Küppers

    2009-12-01

    Full Text Available Temporary ponds represent special environments that are inhabited by organisms adapted to changing environmental conditions. Ciliates are able to survive complete loss of water in these transient habitats through cyst formation. However, ciliates from the Neotropical region in general have been poorly studied with modern techniques. The main goal of this study is to describe the ciliates in dried sediments of a temporary pond from Buenos Aires Province, Argentina, through sampling efforts that were performed 2003-2005. Soil samples were obtained during drought phases and re wetted in laboratory to establish raw and enriched cultures. Ciliates were then studied both in vivo and after impregnation with protargol. In this study, we present 4 new records for Argentina (Gonostomum affine (Stein, 1859 Sterki, 1878, Stylonychia bifaria (Stokes, 1887 Berger, 1999, Pleurotricha lanceolata (Ehrenberg, 1835 Stein, 1859, Meseres corlissi Petz and Foissner, 1992, 1 for South America (Blepharisma americanum (Suzuki, 1954 Hirshfield, Isquith and Bhandary, 1965, and 2 for the Neotropical Realm (Gonostomum strenuum (Engelmann, 1862 Sterki, 1878, Stylonychia lemnae Ammermann and Schlegel, 1983.Los cuerpos de agua temporarios son ambientes particulares que se encuentran habitados por organismos adaptados a condiciones fluctuantes. Los ciliados son capaces de sobrevivir a la pérdida completa de agua del ambiente gracias a la formación de estructuras de resistencia. Por otra parte, los ciliados de la región Neotropical han sido poco investigados con técnicas modernas. El objetivo de este estudio es referir los ciliados que se desarrollaron a partir de los sedimentos secos de una charca temporaria de la provincia de Buenos Aires, Argentina, en la que se realizaron muestreos durante el período 2003-2005. Las muestras de suelo fueron obtenidas durante las fases de sequía y luego resuspendidas en el laboratorio para realizar cultivos naturales y enriquecidos. Los

  9. Is contextual-potentiated eating dependent on caloric density of food?

    Directory of Open Access Journals (Sweden)

    Fernando Fernández-Aranda

    2009-01-01

    Full Text Available One experiment tested whether a specific context could elicit eating in rats as a result of Pavlovian conditioning and whether this effect depended on the caloric density of food. Thirty two deprived rats experienced two contexts. They had access to food in context A, but no food was available in context B. During conditioning, half of the animals received high density caloric food (HD groups whereas the other half, low density caloric food (LD groups. Then, half of the rats in each type of food group was tested in context A and the other half in context B. The results demonstrated an effect of context conditioning only in HD groups. These findings suggest the relevance of both contextual conditioning and caloric density of food in eating behaviour. Implications for the aetiology of binge eating will be discussed.

  10. Relationship between caloric intake and length of hospital stay for infants with bronchiolitis.

    Science.gov (United States)

    Weisgerber, Michael C; Lye, Patricia S; Nugent, Melodee; Li, Shun-Hwa; De Fouw, Kari; Gedeit, Rainer; Simpson, Pippa; Gorelick, Marc H

    2013-01-01

    Poor oral intake is a common presenting symptom among infants hospitalized with bronchiolitis. The prevalence, degree, and duration of iminished caloric intake in these infants have not been studied. Our goal was to determine the daily caloric intake among infants admitted with bronchiolitis and to evaluate the relationship between early hospital caloric intake and length of stay (LOS). We conducted a retrospective chart review of infants aged or =183 days. Caloric intake was diminished in the early course of hospitalization for infants who had bronchiolitis and slowest to normalize in infants with the longest LOS. Interventions aimed at decreasing LOS among infants admitted with bronchiolitis should consider the potential significance of nutrition for severely affected infants with this condition.

  11. Palatable Hyper-Caloric Foods Impact on Neuronal Plasticity.

    Science.gov (United States)

    Morin, Jean-Pascal; Rodríguez-Durán, Luis F; Guzmán-Ramos, Kioko; Perez-Cruz, Claudia; Ferreira, Guillaume; Diaz-Cintra, Sofia; Pacheco-López, Gustavo

    2017-01-01

    Neural plasticity is an intrinsic and essential characteristic of the nervous system that allows animals "self-tuning" to adapt to their environment over their lifetime. Activity-dependent synaptic plasticity in the central nervous system is a form of neural plasticity that underlies learning and memory formation, as well as long-lasting, environmentally-induced maladaptive behaviors, such as drug addiction and overeating of palatable hyper-caloric (PHc) food. In western societies, the abundance of PHc foods has caused a dramatic increase in the incidence of overweight/obesity and related disorders. To this regard, it has been suggested that increased adiposity may be caused at least in part by behavioral changes in the affected individuals that are induced by the chronic consumption of PHc foods; some authors have even drawn attention to the similarity that exists between over-indulgent eating and drug addiction. Long-term misuse of certain dietary components has also been linked to chronic neuroimmune maladaptation that may predispose individuals to neurodegenerative conditions such as Alzheimer's disease. In this review article, we discuss recent evidence that shows how consumption of PHc food can cause maladaptive neural plasticity that converts short-term ingestive drives into compulsive behaviors. We also discuss the neural mechanisms of how chronic consumption of PHc foods may alter brain function and lead to cognitive impairments, focusing on prenatal, childhood and adolescence as vulnerable neurodevelopmental stages to dietary environmental insults. Finally, we outline a societal agenda for harnessing permissive obesogenic environments.

  12. Fasting and Caloric Restriction in Cancer Prevention and Treatment.

    Science.gov (United States)

    Brandhorst, Sebastian; Longo, Valter D

    Cancer is the second leading cause of death in the USA and among the leading major diseases in the world. It is anticipated to continue to increase because of the growth of the aging population and prevalence of risk factors such as obesity, smoking, and/or poor dietary habits. Cancer treatment has remained relatively similar during the past 30 years with chemotherapy and/or radiotherapy in combination with surgery remaining the standard therapies although novel therapies are slowly replacing or complementing the standard ones. According to the American Cancer Society, the dietary recommendation for cancer patients receiving chemotherapy is to increase calorie and protein intake. In addition, there are no clear guidelines on the type of nutrition that could have a major impact on cancer incidence. Yet, various forms of reduced caloric intake such as calorie restriction (CR) or fasting demonstrate a wide range of beneficial effects able to help prevent malignancies and increase the efficacy of cancer therapies. Whereas chronic CR provides both beneficial and detrimental effects as well as major compliance challenges, periodic fasting (PF), fasting-mimicking diets (FMDs), and dietary restriction (DR) without a reduction in calories are emerging as interventions with the potential to be widely used to prevent and treat cancer. Here, we review preclinical and preliminary clinical studies on dietary restriction and fasting and their role in inducing cellular protection and chemotherapy resistance.

  13. Coeficientes de transferencia de calor y pérdida de eficiencia en intercambiadores de calor de placas durante el enfriamiento del licor amoniacal

    OpenAIRE

    Enrique Torres-Tamayo; Luís E. Quintana-Charlot; Orlando Vega-Arias; Yoalbys Retirado-Mediaceja

    2011-01-01

    En la planta de Recuperación de Amoniaco de la empresa niquelera Ernesto Che Guevara la pérdida de eficiencia del proceso de enfriamiento del licor amoniacal, mediante el uso de intercambiadores de calor de placas, se asocia a la incorrecta estimación de los coeficientes de transferencia de calor y la acumulación de incrustaciones en la superficie de intercambio; lo anterior incrementa el consumo de agua, la energía disponible en el sistema y los costos de mantenimiento. Se realizó una invest...

  14. Comportamentos das Famílias Portuguesas em Épocas de Calor e Durante a Onda de Calor de Agosto de 2003

    OpenAIRE

    Nogueira, Paulo; Paixão, Eleonora; Falcão, José Marinho

    2005-01-01

    Este estudo teve como principal objectivo a caracterização das atitudes e da adopção de medidas de protecção em períodos de calor e em particular conhecer aquelas que efectivamente foram adoptadas durante a onda de calor de Agosto de 2003 (29 de Julho a 15 de Agosto). Foi realizado um inquérito por via postal, aplicando um questionário aos indivíduos de 18 e mais anos das unidades de alojamento (UA), que constituem a amostra ECOS (Em Casa Observamos Saúde) do Observatório Nacional de Saúd...

  15. Comportamentos das famílias portuguesas em épocas de calor e durante a onda de calor de Agosto de 2003

    OpenAIRE

    Nogueira, Paulo Jorge; Paixão, Eleonora de Jesus; Falcão, José Marinho

    2005-01-01

    RESUMO - Este estudo teve como principal objectivo a caracterização das atitudes e da adopção de medidas de protecção em períodos de calor e em particular conhecer aquelas que efectivamente foram adoptadas durante a onda de calor de Agosto de 2003 (29 de Julho a 15 de Agosto). Foi realizado um inquérito por via postal, aplicando um questionário aos indivíduos de 18 e mais anos das unidades de alojamento (UA), que constituem a amostra ECOS (Em Casa Observamos Saúde) do ...

  16. MODELADO DE DINÁMICA DE FLUIDOS Y TRANSFERENCIA DE CALOR Y MASA EN PROCESOS AGROALIMENTARIOS POR MÉTODO DE VOLÚMENES FINITOS

    Directory of Open Access Journals (Sweden)

    NELSON O. MORAGA

    2011-01-01

    Full Text Available Se describe la transferencia de momento, calor y masa transitorio bi-dimensional en procesos agroalimentarios. Estos procesos son: la pre-cosecha y la deshidratación por aire caliente de frutas. La metodología incluye modelación matemática y simulación computacional para describir la convección y difusión de calor y masa conjugada que resulta de la interacción entre el alimento y el aire. El modelo matemático emplea las ecuaciones diferenciales parciales no lineales acopladas de continuidad, momento lineal, energía y materia. Se considera que las propiedades físicas de las frutas calculadas mediante correlaciones empíricas, varían con la temperatura y la concentración de humedad. El método de volúmenes finitos junto el algoritmo SIMPLE se utiliza para obtener los resultados de la variación en el tiempo de las distribuciones de velocidades (v, temperaturas (T y concentraciones de humedad (C para los procesos en estudio. Las propiedades termofísicas variables de los alimentos se obtuvieron a partir de modelos empíricos. Los resultados obtenidos incluyen distribuciones de las variables dependientes (v, T, C en el tiempo, los cuales se comparan con resultados experimentales y numéricos de la literatura especializada.

  17. Use of caloric and noncaloric sweeteners in US consumer packaged foods, 2005-2009.

    Science.gov (United States)

    Ng, Shu Wen; Slining, Meghan M; Popkin, Barry M

    2012-11-01

    Our understanding of the use of caloric and noncaloric sweeteners in the US food supply is limited. This study uses full ingredient list and Nutrition Facts label data from Gladson Nutrition Database and nationally representative purchases of consumer packaged foods from Nielsen Homescan in 2005 through 2009 to understand the use of caloric sweeteners (including fruit juice concentrate) and noncaloric sweeteners in consumer packaged foods. Of the 85,451 uniquely formulated foods purchased during 2005 through 2009, 75% contain sweeteners (68% with caloric sweetener only, 1% with noncaloric sweetener only, 6% with both caloric and noncaloric sweeteners). Caloric sweetener are in >95% of cakes/cookies/pies, granola/protein/energy bars, ready-to-eat cereals, sweet snacks, and sugar-sweetened beverages. Noncaloric sweetener are in >33% of yogurts and sport/energy drinks, 42% of waters (plain or flavored), and most dietetic sweetened beverages. Across unique products, corn syrup is the most commonly listed sweetener, followed by sorghum, cane sugar, high-fructose corn syrup, and fruit juice concentrate. Also, 77% of all calories purchased in the United States in 2005-2009 contained caloric sweeteners and 3% contained noncaloric sweeteners, and 73% of the volume of foods purchased contained caloric sweetener and 15% contained noncaloric sweetener. Trends during this period suggest a shift toward the purchase of noncaloric sweetener-containing products. Our study poses a challenge toward monitoring sweetener consumption in the United States by discussing the need and options available to improve measures of caloric sweetener and noncaloric sweetener and additional requirements on Nutrition Facts labels on consumer packaged foods. Copyright © 2012 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

  18. Caloric restriction decreases orthostatic tolerance independently from 6° head-down bedrest.

    Directory of Open Access Journals (Sweden)

    John P Florian

    Full Text Available Astronauts consume fewer calories during spaceflight and return to earth with an increased risk of orthostatic intolerance. Whether a caloric deficiency modifies orthostatic responses is not understood. Thus, we determined the effects of a hypocaloric diet (25% caloric restriction during 6° head down bedrest (an analog of spaceflight on autonomic neural control during lower body negative pressure (LBNP. Nine healthy young men completed a randomized crossover bedrest study, consisting of four (2 weeks each interventions (normocaloric bedrest, normocaloric ambulatory, hypocaloric bedrest, hypocaloric ambulatory, each separated by 5 months. Muscle sympathetic nerve activity (MSNA was recorded at baseline following normocaloric and hypocaloric interventions. Heart rate (HR and arterial pressure were recorded before, during, and after 3 consecutive stages (7 min each of LBNP (-15, -30, -45 mmHg. Caloric and posture effects during LBNP were compared using two-way ANOVA with repeated measures. There was a strong trend toward reduced basal MSNA following caloric restriction alone (normcaloric vs. hypocaloric: 22±3 vs. 14±4 burst/min, p = 0.06. Compared to the normocaloric ambulatory, both bedrest and caloric restriction were associated with lower systolic blood pressure during LBNP (p<0.01; however, HR responses were directionally opposite (i.e., increase with bedrest, decrease with caloric restriction. Survival analysis revealed a significant reduction in orthostatic tolerance following caloric restriction (normocaloric finishers: 12/16; hypocaloric finishers: 6/16; χ2, p = 0.03. Caloric restriction modifies autonomic responses to LBNP, which may decrease orthostatic tolerance after spaceflight.

  19. The comparative effect of fasting with and without caloric restriction in Rat on oxidative stress parameters

    OpenAIRE

    Nurina Tyagita; Taufiqurrachman Nasihun; Titiek Sumarawati

    2016-01-01

    Introduction: Fasting, like Islamic Ramadan Fasting, has been associated with health benefits. Islamic Ramadan fasting, a form of caloric restriction (CR) or alternate day fasting that. Studies suggest a comparable effect of ADF and caloric restriction. Despite the fact that fasting can be considered as a form of dietary restriction, fasters tend to have difficulty to reduce their food intake during non-fasting period by overeating leading to the excessive calorie intake. To compare the effec...

  20. Weight Cycling and Cancer: Weighing the Evidence of Intermittent Caloric Restriction and Cancer Risk

    OpenAIRE

    Henry J. Thompson; McTiernan, Anne

    2011-01-01

    Overweight and obese individuals frequently restrict caloric intake to lose weight. The resultant weight loss, however, typically is followed by an equal or greater weight gain, a phenomenon called weight cycling. Most attention to weight cycling has focused on identifying its detrimental effects, but preclinical experiments indicating that intermittent caloric restriction or fasting can reduce cancer risk have raised interest in potential benefits of weight cycling. Although hypothesized adv...

  1. Postoral Glucose Sensing, Not Caloric Content, Determines Sugar Reward in C57BL/6J Mice

    Science.gov (United States)

    Zukerman, Steven; Ackroff, Karen

    2015-01-01

    Recent studies suggest that because of their energy value, sugars are more rewarding than non-caloric sweeteners. However, intragastric infusion data indicate that sugars differ in their postoral appetite-stimulating effects. We therefore compared the preference for isocaloric 8% sucrose, glucose, and fructose solutions with that of a non-caloric sweetener solution (0.8% sucralose) in C57BL/6J mice. Brief 2-bottle tests indicated that sucralose was isopreferred to sucrose but more preferred than glucose or fructose. Yet, in long-term tests, the mice preferred sucrose and glucose, but not fructose to sucralose. Additional experiments were conducted with a non-caloric 0.1% sucralose + 0.1% saccharin mixture (S + S), which does not have the postoral inhibitory effects of 0.8% sucralose. The S + S was preferred to fructose in brief and long-term choice tests. S + S was also preferred to glucose and sucrose in brief tests, but the sugars were preferred in long-term tests. In progressive ratio tests, non-deprived and food-deprived mice licked more for glucose but not fructose than for S + S. These findings demonstrate that the nutrient-specific postoral actions, not calories per se, determine the avidity for sugar versus non-caloric sweeteners. Furthermore, sweet taste intensity and potential postoral inhibitory actions must be considered in comparing non-caloric and caloric sweeteners. PMID:25715333

  2. Diseño óptimo de un disipador de calor para luminaria LED mediante moderación modelación computacional

    Directory of Open Access Journals (Sweden)

    Daniel Cahue Díaz

    2014-01-01

    Full Text Available En el presente trabajo se desarrolla una selección de materiales y simulación térmica en el diseño de disipadores de calor para sistemas de iluminación de estado sólido (SSL mejor conocidos como luminarias LEDs. Se desarrolló un modelo matemático con la capacidad de predecir el comportamiento térmico de la luminaria cuando se encuentra en operación. El modelo matemático fue resuelto mediante un software de distribución libre el cual permite resolver ecuaciones diferenciales mediante el método de elemento finito. Los resultados obtenidos en el modelo matemático planteado fueron validados con los resultados obtenidos mediante experimentación usando imágenes termográficas.

  3. Cementos con cenizas volantes

    Directory of Open Access Journals (Sweden)

    Ossa M., Mauricio

    1984-03-01

    additions of 20 and 30% .

    Casi la generalidad de los estudios realizados sobre cementos con adición de cenizas volantes se refieren a sus características y comportamiento en pastas, morteros y hormigones, siempre en relación con aquéllos del cemento portland. Esta vez, se desarrolló un trabajo experimental orientado a relacionar entre sí los cementos con adiciones de cenizas volantes y de puzolana natural. Para ello se fabricaron a escala de laboratorio cementos de ambos tipos, empleando como materias primas comunes clinker y yeso y, como variables, diferentes porcentajes de las dos adiciones, que cumplieron previamente los requisitos normalizados en cuanto a sus actividades puzolánicas. La calidad de los cementos fabricados resultó adecuada y concordante con la del cemento portland-puzolánico obtenido a escala industrial con los mismos clinker, yeso y puzolana natural de este estudio. Posteriormente, se determinaron las características de los cementos experimentales y se confeccionaron morteros normales para la realización de ensayos físicos y mecánicos. Los resultados de ensayos indicaron que los cementos con adición de cenizas volantes (CCV requieren menos agua para consistencia normal, presentan tiempos de fraguado mayores y expansiones en autoclave menores que los cementos con adición de puzolana (CP. Los calores de hidratación a 7 y 28 días de edad fueron aproximadamente similares para ambos tipos de cemento. En morteros normales, los cementos CCV mostraron menor retracción de secado, mayor retentividad y mayor fluidez (para igual cantidad de agua que los cementos CP. En los ensayos de exudación se observó que ésta depende más de la finura que el tipo de adición. Finalmente, los ensayos mecánicos señalaron que las resistencias a compresión y flexotracción de los morteros con cementos CCV son menores a edades inferiores que 14 días (del orden de 5 a 10% a un día de edad, pero que a partir de entonces pasan a ser mayores que las de

  4. Effects of seco-steroids purified from Physalis angulata L., Solanaceae, on the viability of Leishmania sp Efeitos de seco-esteróides purificados de Physalis angulata L., Solanaceae na viabilidade de Leishmania sp

    Directory of Open Access Journals (Sweden)

    Elisalva T. Guimarães

    2010-12-01

    Full Text Available Physalis angulata L., Solanaceae, is an annual herb commonly used in popular medicine in many tropical and subtropical countries. P. angulata extracts contain a variety of substances, but little is known about their pharmacological activities. In this work we investigated the in vitro antileishmanial activity of seco-steroids (physalins purified from P. angulata. Addition of physalins B, F, and G caused a concentration-dependent inhibition in the growth of L. amazonensis promastigotes, being the IC50 values were 6.8, 1.4, and 9.2 μM, respectively. Physalin D was less active and had an IC50 value of 30.5 μM. Physalins were also active in cultures of other Leishmania species (L. major, L. braziliensis, and L. chagasi. Our results demonstrate the potent antileishmanial activity of physalins in cultures of Leishmania species of the New and Old Worlds and suggest the therapeutic potential of these seco-steroids in leishmaniasis.Physalis angulata L., Solanaceae, é uma erva anual utilizada na medicina popular em muitos países tropicais e subtropicais. Apesar dos extratos da P. angulata apresentarem uma grande variedade de substâncias, pouco é conhecido sobre a sua atividade farmacológica. Neste trabalho foi investigado a atividade antileishmania in vitro de seco-esteroides (fisalinas purificados da P. angulata. O tratamento com as fisalinas B, F e G causou uma inibição concentração-dependente do crescimento de promastigotas de Leishmania amazonensis em cultura axênica, com valores de IC50 de 6,8, 1,4, e 9,2 μM respectivamente. A fisalina D foi menos ativa, com valores de IC50 de 30,5 μM. Foi também observada uma atividade leishmanicida em culturas de outras espécies de Leishmania (L. major, L. braziliensis e L. chagasi. Nossos resultados demonstram que as fisalinas inibem o crescimento dos promastigotas com o tratamento de espécies de Leishmania do Velho e do Novo Mundos e sugerem o potencial terapêutico destas moléculas na

  5. Transferencia de calor y su efecto en el proceso de prensado de tableros contrachapados

    Directory of Open Access Journals (Sweden)

    D. Zavala Zavala

    2004-01-01

    Full Text Available El proceso de prensado determina la calidad de los contrachapados (triplay a través de la interrelación de las propiedades tecnológicas de la madera, de las características de los adhesivos y de la interacción de la temperatura y presión que se generan en la prensa. Este trabajo se realizó con la finalidad de analizar el efecto de la transferencia de calor en la polimerización de adhesivos preparados con urea y fenol formaldehído, para determinar la secuela optima de prensado de triplay de 6, 9, 12, 15, 18 y 34 mm de espesor; y para evaluar la compactación de los tableros por efecto de la temperatura y presión durante el prensado. Se utilizó chapa de Pinus herrerai Martínez, P. michoacana Martínez y P. pseudostrobus Lindl., a un contenido de humedad de 6 a 8 %, una prensa calentada con vapor, adhesivo de urea formaldehído para tableros para interiores de 6, 9, 12, 15 y 18 mm y fenol formaldehído para triplay para exteriores de 34 mm de espesor. Se utilizaron ciclos de prensado aplicando temperaturas de 115, 130 y 140 °C y presiones de 10.62 kg·cm-2 (151 psi y 8.51 kg·cm-2 (121 psi en triplay para interiores, y para los tableros tipo exterior de 140, 150 y 160 °C de temperatura y 12.23, 13.29 y 14.34 kg·cm-2 (174, 189 y 204 psi de presión. La temperatura de las líneas de pegamento más externas aumenta rápidamente al cerrarse la prensa y manifiesta una diferencia en relación a las más internas, que tiende a reducirse conforme transcurre el tiempo de prensado, igualándose aproximadamente al 73 % del tiempo para cada tipo de tablero. A través de la evaluación de adhesión de los pegamentos de los tableros para interiores con la norma PS1-95, se determinó que todos pasan las especificaciones requeridas para ese uso En los tableros de 34 mm de espesor, con un incremento de la temperatura de 140 a 160 °C, una presión de 12.23 a 14.34 kg·cm-2 (174 a 204 psi y un contenido de sólidos del fenol formaldehído de 29.9 a 32

  6. Palatable Hyper-Caloric Foods Impact on Neuronal Plasticity

    Science.gov (United States)

    Morin, Jean-Pascal; Rodríguez-Durán, Luis F.; Guzmán-Ramos, Kioko; Perez-Cruz, Claudia; Ferreira, Guillaume; Diaz-Cintra, Sofia; Pacheco-López, Gustavo

    2017-01-01

    Neural plasticity is an intrinsic and essential characteristic of the nervous system that allows animals “self-tuning” to adapt to their environment over their lifetime. Activity-dependent synaptic plasticity in the central nervous system is a form of neural plasticity that underlies learning and memory formation, as well as long-lasting, environmentally-induced maladaptive behaviors, such as drug addiction and overeating of palatable hyper-caloric (PHc) food. In western societies, the abundance of PHc foods has caused a dramatic increase in the incidence of overweight/obesity and related disorders. To this regard, it has been suggested that increased adiposity may be caused at least in part by behavioral changes in the affected individuals that are induced by the chronic consumption of PHc foods; some authors have even drawn attention to the similarity that exists between over-indulgent eating and drug addiction. Long-term misuse of certain dietary components has also been linked to chronic neuroimmune maladaptation that may predispose individuals to neurodegenerative conditions such as Alzheimer’s disease. In this review article, we discuss recent evidence that shows how consumption of PHc food can cause maladaptive neural plasticity that converts short-term ingestive drives into compulsive behaviors. We also discuss the neural mechanisms of how chronic consumption of PHc foods may alter brain function and lead to cognitive impairments, focusing on prenatal, childhood and adolescence as vulnerable neurodevelopmental stages to dietary environmental insults. Finally, we outline a societal agenda for harnessing permissive obesogenic environments. PMID:28261067

  7. Cardioprotective Signature of Short-Term Caloric Restriction.

    Directory of Open Access Journals (Sweden)

    Hossein Noyan

    Full Text Available To understand the molecular pathways underlying the cardiac preconditioning effect of short-term caloric restriction (CR.Lifelong CR has been suggested to reduce the incidence of cardiovascular disease through a variety of mechanisms. However, prolonged adherence to a CR life-style is difficult. Here we reveal the pathways that are modulated by short-term CR, which are associated with protection of the mouse heart from ischemia.Male 10-12 wk old C57bl/6 mice were randomly assigned to an ad libitum (AL diet with free access to regular chow, or CR, receiving 30% less food for 7 days (d, prior to myocardial infarction (MI via permanent coronary ligation. At d8, the left ventricles (LV of AL and CR mice were collected for Western blot, mRNA and microRNA (miR analyses to identify cardioprotective gene expression signatures. In separate groups, infarct size, cardiac hemodynamics and protein abundance of caspase 3 was measured at d2 post-MI.This short-term model of CR was associated with cardio-protection, as evidenced by decreased infarct size (18.5±2.4% vs. 26.6±1.7%, N=10/group; P=0.01. mRNA and miR profiles pre-MI (N=5/group identified genes modulated by short-term CR to be associated with circadian clock, oxidative stress, immune function, apoptosis, metabolism, angiogenesis, cytoskeleton and extracellular matrix (ECM. Western blots pre-MI revealed CR-associated increases in phosphorylated Akt and GSK3ß, reduced levels of phosphorylated AMPK and mitochondrial related proteins PGC-1α, cytochrome C and cyclooxygenase (COX IV, with no differences in the levels of phosphorylated eNOS or MAPK (ERK1/2; p38. CR regimen was also associated with reduced protein abundance of cleaved caspase 3 in the infarcted heart and improved cardiac function.

  8. Guaianolides and a seco-Eudesmane from the Resinous Exudates of Cushion Bush (Leucophyta brownii) and Evaluation of Their Cytostatic and Anti-inflammatory Activity

    DEFF Research Database (Denmark)

    Hyldgaard, Mette G; Purup, Stig; Bond, Andrew D

    2015-01-01

    A detailed phytochemical investigation of a dichloromethane extract of the resinous exudates of the cushion bush plant (Leucophyta brownii) resulted in the isolation of the new 8,12-guaianolides leucophytalins A (5) and B (6), the new 1,10-seco-eudesmane leucophytalin C (10), six rare 8...

  9. Replacing sweetened caloric beverages with drinking water is associated with lower energy intake.

    Science.gov (United States)

    Stookey, Jodi D; Constant, Florence; Gardner, Christopher D; Popkin, Barry M

    2007-12-01

    Reduced intake of sweetened caloric beverages (SCBs) is recommended to lower total energy intake. Replacing SCBs with non-caloric diet beverages does not automatically lower energy intake, however. Compensatory increases in other food or beverages reportedly negate benefits of diet beverages. The purpose of this study was to evaluate drinking water as an alternative to SCBs. Secondary analysis of data from the Stanford A TO Z intervention evaluated change in beverage pattern and total energy intake in 118 overweight women (25 to 50 years) who regularly consumed SCBs (>12 ounces/d) at baseline. At baseline and 2, 6, and 12 months, mean daily beverage intake (SCBs, drinking water, non-caloric diet beverages, and nutritious caloric beverages), food composition (macronutrient, water, and fiber content), and total energy intake were estimated using three 24-hour diet recalls. Beverage intake was expressed in relative terms (percentage of beverages). In fixed effects models that controlled for total beverage intake, non-caloric and nutritious caloric beverage intake (percentage of beverages), food composition, and energy expenditure [metabolic equivalent (MET)], replacing SCBs with drinking water was associated with significant decreases in total energy intake that were sustained over time. The caloric deficit attributable to replacing SCBs with water was not negated by compensatory increases in other food or beverages. Replacing all SCBs with drinking water was associated with a predicted mean decrease in total energy of 200 kcal/d over 12 months. The results suggest that replacing SCBs with drinking water can help lower total energy intake in overweight consumers of SCBs motivated to diet.

  10. Computational program to design heat pumps by compression (ciclo 1.0); Programa computacional para diseno de bombas de calor por compresion (ciclo 1.0)

    Energy Technology Data Exchange (ETDEWEB)

    De Alba Rosano, Mauricio [CIE, UNAM, Temixco, Morelos (Mexico)

    2000-07-01

    A new computational program has been developed in order to design single stage compression heat pumps. This software, named CICLO 1.0 allows the design of water-water, water-air, air-water and air-air heat pumps, for industrial and residential applications. CICLO 1.0 simulates three types of compressors: reciprocating, screw and scroll. Also has a data base created with REFPROP software which includes eleven refrigerants. The condenser and evaporator simulation includes global conductance (UA) determination, and when one or both are shell and tube's type, this software shows the even number of tube passes by shell. The software determines the best compressor and refrigerant setup taking the COP as a parameter; in order to obtain this, is necessary to know the inlet/outlet conditions of the fluid to be heated, the inlet conditions of the fluid that gives heat, and the electric motor efficiency that drives the compressor. The afforded results by CICLO 1.0 are: operation conditions from compression cycle, that means, pressures and temperatures at the inlet/outlet from every heat pump component are determined: as well as refrigerant mass flux, COP, power required by compressor, volumetric and isentropic efficiencies, heat exchangers global conductance and more data. CICLO 1.0 has been executed with heat pump data that nowadays are operating, and the results from the simulation have been very similar each other with data reported from operational facilities. [Spanish] Se ha desarrollado un nuevo programa computacional para el diseno de bombas de calor por compresion de vapor de una sola etapa. Este programa, CICLO 1.0, permite el diseno de bombas de calor de tipo: agua-agua, agua-aire, aire-agua y aire-aire, que se utilicen para aplicaciones industriales, de servicios y residenciales. CICLO 1.0 simula tres tipos de compresores: reciprocante, de tornillo y scroll: cuenta con una base de datos de refrigerantes creada con el programa REFPROP la cual incluye once

  11. Estudo do Sujamento da Superfície de Transferência de Calor do Evaporador de uma Bomba de Calor aquecido pelo efluente de uma fábrica de pasta para papel

    OpenAIRE

    Fernandes, Sofia Assunção

    2010-01-01

    O presente trabalho tem como principal objectivo a avaliação do sujamento da superfície de transferência de calor do evaporador de uma bomba de calor, quando se utiliza o efluente da fábrica de pasta e papel da Portucel Soporcel em Cacia como fluido de aquecimento. Para a realização deste estudo montou-se uma instalação, composta por uma bomba de calor, um circuito de água de arrefecimento do condensador da bomba de calor e um circuito de água residual quente para o aquecimento do evaporador ...

  12. Protozoários ruminais de novilhos de corte criados em pastagem tropical durante o período seco

    OpenAIRE

    Kellerson Luiz da Silva; Eduardo Robson Duarte; Claudio Eduardo Silva Freitas; Flávia Oliveira Abrão; Luciana Castro Geraseev

    2014-01-01

    Protozoários do rúmen podem representar 40% do nitrogênio total e 60% do produto final da fermentação e apresentam atividade celulolítica. Neste estudo, objetivou-se quantificar e identificar as populações de protozoários no rúmen de novilhos, criados exclusivamente em pastagem, durante o período seco do ano, no Norte de Minas Gerais. Amostras do suco ruminal de 36 novilhos mestiços Nelore foram coletadas diretamente do rúmen, após o abate, durante o inicio, meio ou fim do período de estiagem...

  13. Estudio comparativo de la determinación del tamaño de partícula por dos métodos : tamizado en seco y disfracción láser

    Directory of Open Access Journals (Sweden)

    Diana Míguez Carames

    2011-05-01

    Full Text Available El objetivo de este trabajo fue comparar el desempeño analítico de la tecnología de medición de tamaño de partícula por difracción láser con la técnica clásica de tamizado en seco para partículas superiores a 80 micras. Se utilizó arena como muestra de referencia interna. El procedimiento mecánico se realizó con equipo vibrador de tamices durante 15 minutos y batería de tamices estándar ASTM números 20, 40, 70 y 170. La determinación por difracción tri-laser, que implica hacer incidir tres haces de luz láser sobre la partícula, permite evaluar las dimensiones y realizar una distribución de tamaños generada por frecuencias de datos dispuestas en rangos. La muestra tamizada se reconstituyó uniendo sus porciones y se cuarteó por separador rotativo de alta exactitud y reproducibilidad. Una muestra representativa se suspendió en agua con agitación mecánica y los datos de las medidas se representaron gráficamente usando el software del equipo. Se realizaron 10 réplicas por cada método para evaluarlos estadísticamente mediante los métodos de los momentos y Falk y Ward. Se concluye que ambos clasifican la muestra de la mismaforma pero existen diferencias en los coeficientes de curtosis para las distribuciones de las poblaciones según una y otra técnicas.

  14. Contribución al conocimiento de las interacciones entre plantas, hormigas y homópteros en bosques secos de Colombia

    Directory of Open Access Journals (Sweden)

    Ramírez Mónica

    2001-12-01

    Full Text Available Las interacciones entre plantas y hormigas y entre plantas, hormigas y homópteros se estudiaron en 248 estaciones de muestreo situadas en nueve fragmentos de bosque seco del valle geográfico del río Cauca, entre enero y junio de 1997. Se registraron 352 interacciones que involucran 91 especies vegetales, hormigas de 67 especies y homópteros pertenecientes a nueve familias. El 4 7% de las asociaciones registradas implica el uso por parte de las hormigas de diferentes estructuras de las plantas (p. e. raíces de las epífitas, domacios en los tallos, hojarasca acumulada entre ramas y hojas, brácteas y peciolos de Heliconia spp. como refugios temporales o sitios de anidamiento. El restante 53% involucra la recolección de miel de homópteros y de sustancias azucaradas en nectarios extraflorales. asmannia auropunctata (17%, Dolichoderus bispinosus (11% Y Brachymyrmex heeri (7% fueron las especies de hormigas registradas con mayor frecuencia. Las plantas más utilizadas fueron Heliconia stricta (8%, Philodendron sp. nov. (7% y Passiflora coriacea (5%. Entre las relaciones observadas, predominan las de tipo generalista, en que las hormigas explotan diferentes recursos aparentemente en forma oportunista y las plantas pueden encontrarse en buen estado a pesar de la ausencia de las hormigas.Interactions between ants and plants and those involving homopterans were studied in 248 sampling points located within nine tropical decidous forest fragments in the Cauca river Valley, between january and june, 1997. A total of 352 interactions were recorded involving 91 plant species, 67 ant species and Homoptera belonging to nine families. 47% ofthe interactions involved ants using different plant structures (such as epiphyte roots, domacia, litter collected in branches and leaves, bracts and petioles of Heliconia spp. as nesting sites or temporary refugia. The remaining 53% involved the collection of homopteran honeydew and sugary substances from extrafloral

  15. The Lexicocalorimeter: Gauging public health through caloric input and output on social media.

    Directory of Open Access Journals (Sweden)

    Sharon E Alajajian

    Full Text Available We propose and develop a Lexicocalorimeter: an online, interactive instrument for measuring the "caloric content" of social media and other large-scale texts. We do so by constructing extensive yet improvable tables of food and activity related phrases, and respectively assigning them with sourced estimates of caloric intake and expenditure. We show that for Twitter, our naive measures of "caloric input", "caloric output", and the ratio of these measures are all strong correlates with health and well-being measures for the contiguous United States. Our caloric balance measure in many cases outperforms both its constituent quantities; is tunable to specific health and well-being measures such as diabetes rates; has the capability of providing a real-time signal reflecting a population's health; and has the potential to be used alongside traditional survey data in the development of public policy and collective self-awareness. Because our Lexicocalorimeter is a linear superposition of principled phrase scores, we also show we can move beyond correlations to explore what people talk about in collective detail, and assist in the understanding and explanation of how population-scale conditions vary, a capacity unavailable to black-box type methods.

  16. Caloric Requirements of Patients With Brain Impairment and Cerebral Palsy Who Are Dependent on Chronic Ventilation.

    Science.gov (United States)

    Gale, Rena; Namestnic, Julia; Singer, Pierre; Kagan, Ilya

    2017-11-01

    Israeli law mandates chronic ventilator support for children and adolescents who are severely brain impaired and show minimal responses. Feeding protocols in these cases have been based on the caloric requirements of healthy children, deducting calories for lack of activity as well as an individual adjustment according to the cerebral palsy growth curves. However, patients are still inclined to gain excessive weight. Our objective was to determine the caloric requirements of these patients. Sixteen patients hospitalized in a dedicated unit who were ventilated through tracheostomies and fed via gastrostomies were included. Patients were aged 3-24 years; duration of ventilation was 1-7.5 years; and diagnoses included congenital genetic or brain malformations (n = 9), hypoxic accidents (n = 4), and postbacterial or postviral encephalitis (n = 3). Resting energy expenditure (REE) was determined by indirect calorimetry. REE values were compared with the caloric requirements of age-comparable healthy children and the calories actually delivered. Data were analyzed with paired t tests, Pearson correlations, and linear regression. The REE of our patients was 46% lower than the estimated caloric requirements of healthy children. In practice, patients received 32% more calories than that measured by REE. These findings were not affected by age, weight, diagnosis, or length of hospitalization. The caloric expenditure of these patients is very low. A diet guided by indirect calorimetry is proposed to aid in providing optimal nutrition support for this unique population to avoid overfeeding and obesity.

  17. Influencia de enmiendas químicas en la recuperación de suelos salinos y sódicos del bosque seco tropical colombiano

    Directory of Open Access Journals (Sweden)

    González M. Adel E.

    1995-06-01

    Full Text Available

    This work was carried out at the greenhouse with de purpose of analyzing the influence of some chemical rectifications on the chemical and agronomic behavior of twelve samples of soils from the Colombian Tropical dry forest; some of these showed high levels of salinity of sodium and magnesium; another organic soil was highley acid-aluminium and magnesium, and other with a very low fertility. The trials were based upon an experimental desing completely at random. Each soil was given three chemical rectifications at two levels or doses, and leaching; a control was just given the leaching. All of the treatments were given two leachings during the essay and two productions of dry matter of sorghum - as the reference plant- were evaluated. At the first essay was proposed to lower until 10 and 5 % of sodium saturation or 20 and 10% of magnesium saturation; in a second essay were applied 50 and 25 t/ha of each chemical rectification; for the third essay the applied doses were 20, 10 and 5 t/ha organic rectifications, such manure and poultry bedding, With the leaching was lowered the salinity in all the soils, below 3 dSm -1; the chemical rectifications, below 4 dS-1; in the majority of the soils. The magnesium and sodium saturation were satisfied in the majority of the treatments using gypsum and sulfuric acid. The pHs were reduced in 95 % in all the soils, but this occurred with most intensity with the sulfuric acid and sulfur than using gypsum. The best physical properties of the soils do not implied that they respond as well in their dry matter productions. Acidic or magnesic soils are best rectified with gypsum. The highest doses of organic rectifications favored the dry matter production.

    El trabajo se realizó en el invernadero de la Facultad de Ciencias Agropecuarias de Palmira, con 12 suelos del Bosque Seco Tropical Colombiano que presentaban problemas de salinidad, sodio y magnesio; un suelo orgánico fuertemente

  18. Aves en ambientes marinos y salinos: viviendo en hábitats secos Birds in marine and saline environments: living in dry habitats

    Directory of Open Access Journals (Sweden)

    PABLO SABAT

    2000-09-01

    Full Text Available Para las aves, ambientes salobres como los marinos y los salares, son en la práctica hábitats secos. Cuando las aves beben agua o consumen presas saladas, sus fluidos corporales aumentan la osmolaridad. Para mantener el equilibrio osmótico, las aves tienen que eliminar el exceso de electrolitos ingerido en los alimentos y el agua. Las estrategias adaptativas utilizadas por las aves marinas incluyen la utilización de la glándula de la sal, la cual produce soluciones de excreción más concentradas que el agua de mar. Tanto la fisiología y la plasticidad de la glándula nasal se correlaciona con las características ecológicas de las especies. Además, las aves pueden minimizar el estrés osmótico escogiendo presas hipo-osmóticas, o con menor contenido de agua, disminuyendo de este modo la ingestión de sales. Aun cuando la capacidad de concentración de la orina del riñón de aves es limitada, existen diferencias interespecíficas en su estructura y fisiología, lo que representa un mecanismo adaptativo para evitar la pérdida de agua. Este órgano es particularmente importante en aquellos taxa que no poseen la glándula de la sal, como paseriformes. Sin embargo, estas aves que aparentemente poseerían una restricción fisiológica para explotar ambientes salobres, incluyen algunas especies que habitan costas oceánicas y de salares. En esta revisión muestro que la interacción funcional del riñón y el intestino grueso en la fisiología osmoregulatoria, junto con la conducta de alimentación juegan un papel crucial en la mantención del balance hídrico y en la adaptación de estas especies a ambientes salobresFor birds, saline environments such as maritime and salt marsh habitats are essentially dry habitats. When birds drink saline water or consume salt-loaded preys, the osmolarity of their body fluids increases. In order to maintain the osmotic equilibrium, they have to eliminate the excess of electrolytes ingested with preys or

  19. REPTILES DEL BOSQUE SECO ESTACIONAL EN EL CARIBE COLOMBIANO: DISTRIBUCIÓN DE LOS HÁBITATS Y DEL RECURSO ALIMENTARIO

    Directory of Open Access Journals (Sweden)

    Luis Eduardo Rojas Murcia

    2016-04-01

    Full Text Available Con el fin de caracterizar la distribución horizontal (repartición de los hábitats y la utilización del recurso alimentario (tipo y tamaño de las presas del ensamblaje de reptiles del bosque seco estacional al norte de la región Caribe de Colombia, en el departamento del Cesar, se realizaron cinco salidas de campo con una duración de doce días cada una. Los muestreos se realizaron en jornadas diurnas y nocturnas, en un diseño de transectos replicados a lo largo de diferentes hábitats que incluyeron: pastizales, bordes e interiores de bosque. Se realizaron análisis descriptivos de uso de hábitat en un perfil de vegetación por cada época climática y análisis de amplitud y sobreposición de nicho. Se registraron 38 especies de 14 familias del orden Squamata. Las especies se distribuyeron de manera homogénea entre zonas abiertas y boscosas. Se encontraron registros de 31 categorías de presa en 109 estómagos de seis especies de serpientes (61 estómagos y siete de lagartos (48 estómagos con un porcentaje de estómagos vacíos de 38 %. Las presas de mayor importancia para los lagartos fueron Coleoptera y Araneae, y para las serpientes fueron los anfibios. La mayoría de las especies presentaron un amplio espectro de dieta y entre especies similares, como entre Anolis auratus y A. gaigei, se presentó uso de recursos similares. En síntesis, el ensamblaje de reptiles presentó una distribución homogénea en los hábitats evaluados (áreas abiertas y boscosas y el recurso alimentario fue variado entre las diferentes especies; la estacionalidad de la zona presenta un papel fundamental en la estructura del ensamblaje de reptiles, presentándose menos abundancia durante la época seca, tanto en las áreas abiertas como en las boscosas.Reptiles from the Seasonal Dry Forest the Caribbean Region: Distribution of Habitat and use of Food ResourceABSTRACTWe assessed the horizontal distribution and use of the food resource of the reptile

  20. Validation of a smooth configuration surface for compact heat exchangers using a numerical method//Validación de la superficie de un intercambiador de calor compacto en configuración lisa utilizando un método numérico

    Directory of Open Access Journals (Sweden)

    José‐L. Leiro‐Garrido

    2014-08-01

    Full Text Available This work determines the thermo hydraulics behavior of smooth configuration surface for a compact heat exchanger by means of numerical simulation. The objective is to use the results as baseline for research in the enhancement of heat transfer and drag reduction, directed to reduce the energy consumption and diminish the environmental impact. The fin tube heat exchanger models described.The constraints used in the implementation of the equation solver are announced. The average heat transfer coefficient and pressure drop obtained from numerical simulation are compare to experimental results presented in literature for models with the same dimensions and configuration. A good agreement between numerical and experimental results is reached. Local mechanisms responsible for the heat transfer and pressure drop are detailed. The study is conducted inside thelaminar regime for frontal velocities ranging between 0.5 and 6 m/s.Key words: compact heat exchanger, heat transfer coefficient, numerical simulation, pressure drop.______________________________________________________________________________ResumenEste trabajo determina el comportamiento termo hidráulico de una superficie perteneciente a un intercambiador de calor compacto en configuración lisa utilizando un método de simulación numérica. El objetivo es caracterizar la superficie para poder utilizarla como una referencia en las comparaciones con superficies de intercambio de calor intensificadas. Los datos obtenidos seutilizaran en la determinación de los valores relativos de intensificación de la transferencia de calor y el arrastre intentando reducir el consumo energético y su impacto ambiental. Se describe el modelo de intercambiador de calor con tubos aletados. Los resultados numéricos obtenidos presentan unbuen ajuste con los valores experimentales. Los resultados del coeficiente de transferencia de calor global y la caída de presión son explicados a partir de las

  1. SirT1 regulates energy metabolism and response to caloric restriction in mice.

    Directory of Open Access Journals (Sweden)

    Gino Boily

    Full Text Available The yeast sir2 gene and its orthologues in Drosophila and C. elegans have well-established roles in lifespan determination and response to caloric restriction. We have studied mice carrying two null alleles for SirT1, the mammalian orthologue of sir2, and found that these animals inefficiently utilize ingested food. These mice are hypermetabolic, contain inefficient liver mitochondria, and have elevated rates of lipid oxidation. When challenged with a 40% reduction in caloric intake, normal mice maintained their metabolic rate and increased their physical activity while the metabolic rate of SirT1-null mice dropped and their activity did not increase. Moreover, CR did not extend lifespan of SirT1-null mice. Thus, SirT1 is an important regulator of energy metabolism and, like its orthologues from simpler eukaryotes, the SirT1 protein appears to be required for a normal response to caloric restriction.

  2. Determinación del calor de fraguado de cemento por icrocalorimetría

    Directory of Open Access Journals (Sweden)

    Liliana Girlado G.

    2010-07-01

    Full Text Available Se determina el calor de fraguado del cemento Río Claro tipo III (Río Claro, Antioquia, Colombia por microcalorimetría de conducción de calor; así como también los efectos de la glucosa y de la sacarosa en el proceso de fraguado de este material. Al emplear 0,15 y 0,05% ( % en peso de estos aditivos en la preparación de las pastas, se observan retardos considerables en el fraguado de las mismas. Los aditivos también modifican el calor de fraguado: la pasta libre de estos presenta un valor de 38,03 J/g en tanto que la adición de glucosa y sacarosa producen valores menores, excepto en el caso de la sacarosa al 0,05% donde se observa un efecto térmico de 55.80 J/s,

  3. Dietary restriction with and without caloric restriction for healthy aging [version 1; referees: 3 approved

    Directory of Open Access Journals (Sweden)

    Changhan Lee

    2016-01-01

    Full Text Available Caloric restriction is the most effective and reproducible dietary intervention known to regulate aging and increase the healthy lifespan in various model organisms, ranging from the unicellular yeast to worms, flies, rodents, and primates. However, caloric restriction, which in most cases entails a 20–40% reduction of food consumption relative to normal intake, is a severe intervention that results in both beneficial and detrimental effects. Specific types of chronic, intermittent, or periodic dietary restrictions without chronic caloric restriction have instead the potential to provide a significant healthspan increase while minimizing adverse effects. Improved periodic or targeted dietary restriction regimens that uncouple the challenge of food deprivation from the beneficial effects will allow a safe intervention feasible for a major portion of the population. Here we focus on healthspan interventions that are not chronic or do not require calorie restriction.

  4. Teoria Construtal e desempenho térmico de Trocadores de Calor Solo-Ar

    OpenAIRE

    Ruth da Silva Brum

    2016-01-01

    Trocadores de Calor Solo-Ar (TCSA) são dispositivos usados para melhorar o condicionamento térmico de ambientes construídos. Eles funcionam através da ventilação do ar por um ou mais dutos enterrados, utilizando o solo como fonte ou sumidouro de calor. Em virtude da defasagem entre as temperaturas do ar e das camadas superficiais da Terra, é possível resfriar o ar no verão e aquecê-lo no inverno. Seus princípios de operação baseiam-se na mecânica dos fluidos e transferência de calor, áreas on...

  5. Sex and race differences in caloric intake during sleep restriction in healthy adults.

    Science.gov (United States)

    Spaeth, Andrea M; Dinges, David F; Goel, Namni

    2014-08-01

    Evidence indicates that men and African Americans may be more susceptible to weight gain resulting from sleep loss than women and whites, respectively. Increased daily caloric intake is a major behavioral mechanism that underlies the relation between sleep loss and weight gain. We sought to assess sex and race differences in caloric intake, macronutrient intake, and meal timing during sleep restriction. Forty-four healthy adults aged 21-50 y (mean ± SD: 32.7 ± 8.7 y; n = 21 women, n = 16 whites) completed an in-laboratory protocol that included 2 consecutive baseline nights [10 or 12 h time in bed (TIB)/night; 2200-0800 or 2200-1000] followed by 5 consecutive sleep-restriction nights (4 h TIB/night; 0400-0800). Caloric intake and meal-timing data were collected during the 2 d after baseline sleep and the first 3 d after sleep restriction. During sleep restriction, subjects increased daily caloric intake (P sleep restriction, exhibited a greater increase in caloric intake during sleep restriction (d = 0.62), and consumed a higher percentage of daily calories during late-night hours (d = 0.78, Ps sleep restriction, or meal timing. However, African Americans consumed more carbohydrates, less protein, and more caffeine-free soda and juice than whites did during the study (Ps sleep loss than women due to a larger increase in daily caloric intake, particularly during late-night hours. These findings are relevant to the promotion of public health awareness by highlighting nutritional risk factors and modifiable behaviors for weight gain related to sleep-wake timing. © 2014 American Society for Nutrition.

  6. Moderate exercise training and chronic caloric restriction modulate redox status in rat hippocampus.

    Science.gov (United States)

    Santin, Katiane; da Rocha, Ricardo Fagundes; Cechetti, Fernanda; Quincozes-Santos, André; de Souza, Daniela Fraga; Nardin, Patrícia; Rodrigues, Letícia; Leite, Marina Concli; Moreira, José Cláudio Fonseca; Salbego, Christianne Gazzana; Gonçalves, Carlos Alberto

    2011-11-03

    Physical activity has been related to antioxidant adaptations, which is associated with health benefits, including those to the nervous system. Additionally, available data suggest exercise and a caloric restriction regimen may reduce both the incidence and severity of neurological disorders. Therefore, our aim was to compare hippocampal redox status and glial parameters among sedentary, trained, caloric-restricted sedentary and caloric-restricted trained rats. Forty male adult rats were divided into 4 groups: ad libitum-fed sedentary (AS), ad libitum-fed exercise training (AE), calorie-restricted sedentary (RS) and calorie-restricted exercise training (RE). The caloric restriction (decrease of 30% in food intake) and exercise training (moderate in a treadmill) were carried out for 3 months. Thereafter hippocampus was surgically removed, and then redox and glial parameters were assessed. Increases in reduced glutathione (GSH) levels and total antioxidant reactivity (TAR) were observed in AE, RS and RE. The nitrite/nitrate levels decreased only in RE. We found a decrease in carbonyl content in AE, RS and RE, while no modifications were detected in thiobarbituric acid reactive substances (TBARS). Total reactive antioxidant potential (TRAP), superoxide dismutase (SOD) activity, S100B and glial fibrilary acid protein (GFAP) content did not change, but caloric restriction was able to increase glutamine synthetase (GS) activity in RS and glutamate uptake in RS and RE. Exercise training, caloric restriction and both combined can decrease oxidative damage in the hippocampus, possibly involving modulation of astroglial function, and could be used as a strategy for the prevention of neurodegenerative diseases. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Postoral glucose sensing, not caloric content, determines sugar reward in C57BL/6J mice.

    Science.gov (United States)

    Sclafani, Anthony; Zukerman, Steven; Ackroff, Karen

    2015-05-01

    Recent studies suggest that because of their energy value, sugars are more rewarding than non-caloric sweeteners. However, intragastric infusion data indicate that sugars differ in their postoral appetite-stimulating effects. We therefore compared the preference for isocaloric 8% sucrose, glucose, and fructose solutions with that of a non-caloric sweetener solution (0.8% sucralose) in C57BL/6J mice. Brief 2-bottle tests indicated that sucralose was isopreferred to sucrose but more preferred than glucose or fructose. Yet, in long-term tests, the mice preferred sucrose and glucose, but not fructose to sucralose. Additional experiments were conducted with a non-caloric 0.1% sucralose + 0.1% saccharin mixture (S + S), which does not have the postoral inhibitory effects of 0.8% sucralose. The S + S was preferred to fructose in brief and long-term choice tests. S + S was also preferred to glucose and sucrose in brief tests, but the sugars were preferred in long-term tests. In progressive ratio tests, non-deprived and food-deprived mice licked more for glucose but not fructose than for S + S. These findings demonstrate that the nutrient-specific postoral actions, not calories per se, determine the avidity for sugar versus non-caloric sweeteners. Furthermore, sweet taste intensity and potential postoral inhibitory actions must be considered in comparing non-caloric and caloric sweeteners. © The Author 2015. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. High-throughput search for caloric materials: the CaloriCool approach

    Science.gov (United States)

    Zarkevich, N. A.; Johnson, D. D.; Pecharsky, V. K.

    2018-01-01

    The high-throughput search paradigm adopted by the newly established caloric materials consortium—CaloriCool®—with the goal to substantially accelerate discovery and design of novel caloric materials is briefly discussed. We begin with describing material selection criteria based on known properties, which are then followed by heuristic fast estimates, ab initio calculations, all of which has been implemented in a set of automated computational tools and measurements. We also demonstrate how theoretical and computational methods serve as a guide for experimental efforts by considering a representative example from the field of magnetocaloric materials.

  9. Effect of consuming different caloric sweeteners on bone health and possible mechanisms.

    Science.gov (United States)

    Tsanzi, Embedzayi; Fitch, Cindy W; Tou, Janet C

    2008-06-01

    Western diets are high in caloric sweeteners and since the 1980s there has been a shift from the use of sucrose as the predominant sweetener to high-fructose corn syrup. This may have important implications for bone, as sugar consumption has been shown to negatively impact mineral balance. This article reviews the existing scientific evidence regarding the effect of caloric sweeteners and the type of sweetener on bone health and the potential mechanisms of action. A better understanding of the role of sugar consumption on mineral balance and bone can contribute to the determination of dietary recommendations to reduce bone loss and the future risk of osteoporosis.

  10. Análisis estructural de un intercambiador de calor de un reactor avanzado

    OpenAIRE

    García Merino, Carlos

    2008-01-01

    El objetivo fundamental de este proyecto consiste en el estudio estructural de un intercambiador de calor de un reactor avanzado de Generación VI. Este intercambiador de calor es el condensador PCCS (Passive Containment Cooling System), sistema de seguridad de una central nuclear ESBWR. El análisis estructural del condensador se ha realizado analítica y numéricamente. El cálculo analítico utiliza expresiones obtenidas del código ASME, para determinar tensiones por presiones internas. Y el cál...

  11. Isotermas e calor isostérico de sementes de Buchenavia capitata (Vahl) Eichler

    OpenAIRE

    Costa,Lílian Moreira; Resende,Osvaldo; Oliveira,Daniel Emanuel Cabral de; Sousa,Kelly Aparecida de

    2015-01-01

    RESUMODiante da importância do conhecimento da higroscopicidade e do calor isostérico para as operações de secagem e armazenamento, objetivou-se neste trabalho determinar as isotermas de dessorção de sementes de Buchenavia capitata (Vahl) Eichler, bem como ajustar diferentes modelos matemáticos aos dados experimentais, selecionando aquele que melhor representa o fenômeno e, assim, utilizá-lo para determinar o calor isostérico de dessorção. Para obtenção do teor de água de equilíbrio higroscóp...

  12. Effects of Experimental Sleep Restriction on Weight Gain, Caloric Intake, and Meal Timing in Healthy Adults.

    Science.gov (United States)

    Spaeth, Andrea M; Dinges, David F; Goel, Namni

    2013-07-01

    Examine sleep restriction's effects on weight gain, daily caloric intake, and meal timing. Repeated-measures experiments assessing body weight at admittance and discharge in all subjects (N = 225) and caloric intake and meal timing across days following 2 baseline nights, 5 sleep restriction nights and 2 recovery nights or across days following control condition nights in a subset of subjects (n = 37). Controlled laboratory environment. Two hundred twenty-five healthy adults aged 22-50 y (n = 198 sleep-restricted subjects; n = 31 with caloric intake data; n = 27 control subjects; n = 6 with caloric intake data). Approximately 8-to-1 randomization to an experimental condition (including five consecutive nights of 4 h time in bed [TIB]/night, 04:00-08:00) or to a control condition (all nights 10 h TIB/night, 22:00-08:00). Sleep-restricted subjects gained more weight (0.97 ± 1.4 kg) than control subjects (0.11 ± 1.9 kg; d = 0.51, P = 0.007). Among sleep-restricted subjects, African Americans gained more weight than Caucasians (d = 0.37, P = 0.003) and males gained more weight than females (d = 0.38, P = 0.004). Sleep-restricted subjects consumed extra calories (130.0 ± 43.0% of daily caloric requirement) during days with a delayed bedtime (04:00) compared with control subjects who did not consume extra calories (100.6 ± 11.4%; d = 0.94, P = 0.003) during corresponding days. In sleep-restricted subjects, increased daily caloric intake was due to more meals and the consumption of 552.9 ± 265.8 additional calories between 22:00-03:59. The percentage of calories derived from fat was greater during late-night hours (22:00-03:59, 33.0 ± 0.08%) compared to daytime (08:00-14:59, 28.2 ± 0.05%) and evening hours (15:00-21:59, 29.4 ± 0.06%; Ps sleep restriction promoted weight gain. Chronically sleep-restricted adults with late bedtimes may be more susceptible to weight gain due to greater daily caloric intake and the consumption of calories during late-night hours

  13. Normal physical activity obliterates the deleterious effects of high-caloric intake

    DEFF Research Database (Denmark)

    Krogh-Madsen, Rikke; Pedersen, Maria; Solomon, Thomas

    2013-01-01

    A high-caloric intake combined with a sedentary lifestyle is an important player in the development of type 2 diabetes mellitus (T2DM). The present study was undertaken to examine if the level of physical activity has impact on the metabolic effects of a high-caloric (+2,000 kcal/day) intake...... function with regard to capacity of attention. In conclusion, we find evidence to support that habitual physical activity may prevent pathophysiological symptoms associated with diet-induced obesity....

  14. Impacto ecológico de los Intercambiadores de calor de tubo y coraza; Ecological impact of Shell and tube heat exchangers

    Directory of Open Access Journals (Sweden)

    Maida Bárbara Reyes Rodríguez

    2015-04-01

    Full Text Available Los intercambiadores de calor de tubo y coraza son de los equipos más importantes en la industria. Su diseño termodinámico se basa en el coeficiente global de transferencia de calor y la caída de presión total. En 2007 se estableció una nueva propiedad termodinámica denominada “Entransía”, que expresa la capacidad de un cuerpo de transferir calor. A la pérdida de esa capacidad se le denomina “Disipación de Entransía”. Para evaluar el impacto ecológico de las máquinas térmicas, Angulo-Brown creó en 1991 la llamada función ecológica. En el presente trabajo se combinó la disipación de entransía con la función ecológica y se creó una nueva expresión para evaluar el impacto ambiental de los intercambiadores de calor. Se realizó además la optimización muti-objetivo de estos equipos. Fueron utilizadas como funciones objetivo la función ecológica y el costo. Para realizar la optimización se utilizó el método de los Algoritmos Genéticos.Shell and tube heat exchangers are ones the most important equipment in the industry. Their thermodynamic design is based on the global heat transference coefficient and the pressure drop. In 2007 was settled a new thermodynamic property denominated “Entransy”, which expresses the capacity of a body to transfer heat. The loss of this capacity is denominated “Entransy Dissipation”. For evaluating the ecological impact of thermal machines, Angulo-Brown created in 1991 the “ecological function”. In this paper the“entransy dissipation” and the ecological function were combined and a new expression for evaluating the ecological impact of shell and tube heat exchangers was created. A multi-objective optimization of this equipment wasalso realized. The ecological function and the cost wereused as objective functions. For carry out the optimization the method of the Genetic Algorithms was used.

  15. Effect of Replacing Sugar with Non-Caloric Sweeteners in Beverages on the Reward Value after Repeated Exposure

    NARCIS (Netherlands)

    Griffioen-Roose, S.; Smeets, P.A.M.; Weijzen, P.L.G.; Rijn, van I.; Bosch, van den I.; Graaf, de C.

    2013-01-01

    Background: The reward value of food is partly dependent on learned associations. It is not yet known whether replacing sugar with non-caloric sweeteners in food is affecting long-term acceptance. Objective: To determine the effect of replacing sugar with non-caloric sweeteners in a nutrient-empty

  16. USO DE PLANTAS EM PÓ SECO COM PROPRIEDADES TERMITICIDA SOBRE A MORTALIDADE DE CUPINS ARBÓREOS

    Directory of Open Access Journals (Sweden)

    Chistopher Stallone Cruz

    2012-09-01

    Full Text Available 1024x768 Normal 0 21 false false false PT-BR X-NONE X-NONE Os térmitas são insetos de grande importância ecológica, com mais de 2.750 espécies catalogadas em todo o mundo. Pequeno número de espécies são conhecidos por provocarem grandes danos econômicos ao homem, sendo considerado como praga urbana ou agrícola, são destruidores de madeira seca, pastagens e outros materiais composto de celulose. A vasta gama de uso indiscriminado de produtos químicos contra o controle deste inseto vem trazendo ao longo do tempo resultados negativos, por apresentarem sérios riscos a saúde humana e dar surgimento a cupins com resistência. Avaliou-se nove espécies vegetais que possivelmente apresentem poder cupinicida em substituição aos tratamentos convencionais, de modo a preservar o meio ambiente. Foram avaliados os seguintes vegetais: caule e folha de Aspidosperma pyrifolium, raiz de Mimosa tenuiflora, raiz de Cnidoscolus urens, gema apical de Syzygium aromaticum, semente de Azadirachta indica, fruto de Piper nigrum, folhas de Eucalyptus sp., raiz de Zingiber officinale e fruto de Punica granatum. Foram coletados 550 espécimes de cupins, 275 operários e 275 soldados, logo em seguida foram distribuídos 10 indivíduos dentro de um cativeiro de polipropileno com capacidade de 250mL, juntamente com 3g do pó seco, 5g de fragmentos de cupinzeiro macerado, verificando a viabilidade dos pós secos durante 5 dias consecutivos, sendo realizado uma leitura de mortalidade a cada 24 horas. O delineamento utilizado foi o inteiramente casualizado e os dados foram avaliados pelos testes Student e Henderson & Tilton. Verificou-se que a utilização dos pós vegetais é  alternativa eficaz e barata no controle de Nasutitermes sp., destacando-se como mais letais folhas e galhos de A. indica,Eucalyptus sp., S. aromaticum, Z. officinale, C. urens e P. nigrum.

  17. Transplante de glândulas salivares labiais no tratamento de olho seco em cães pela autoenxertia

    Directory of Open Access Journals (Sweden)

    Leticia Séra Castanho

    2013-12-01

    Full Text Available OBJETIVO: Avaliar os efeitos clínicos da secreção das glândulas salivares labiais como alternativa de lubrificação ocular para alívio do olho seco, em casos moderados, severos e refratários ao tratamento clínico, através da técnica de transposição de glândulas salivares labiais para o fórnice conjuntival pela autoenxertia. MÉTODOS: Foram selecionados 17 cães os quais apresentavam olho seco autoimune sem reposta satisfatória ao tratamento clínico. O teste lacrimal de Schirmer e o tempo de ruptura do filme lacrimal foram realizados no pré-operatório para avaliar a quantidade e a qualidade da lágrima produzida. Os pacientes foram submetidos aos exames oftálmicos completos no pré-operatório, a cada 15 dias por dois meses e a cada 30 dias por mais dois meses, totalizando seis retornos pós-operatórios. No pré-operatório e em todos os pós-operatórios fotografias digitais foram tiradas para o arquivo fotográfico. Utilizou-se o programa photoshop para avaliação e marcação dos neovasos corneanos em todos os retornos. RESULTADOS: Houve redução em todos os casos da secreção mucopurulenta, hiperemia conjuntival e blefarospasmo, bem como estabilização de lesões pré-existentes e redução importante do número de neovasos corneanos. A transposição resultou na melhora do tempo de ruptura do filme lacrimal, porém sem alterações significativas no teste de Schirmer. CONCLUSÃO: O transplante das glândulas salivares labiais para o fórnice conjuntival é um procedimento de fácil execução, rápido, eficaz, acessível a qualquer cirurgião veterinário oftalmologista e de grande valia para casos moderados e severos de ceratoconjuntivite seca não responsivos às medicações existentes.

  18. Monitoreo de procesos de ecológicos del Bosque Seco Tropical: Aplicaciones de sensores remotos para estimaciones a nivel de paisaje y el cambio global

    OpenAIRE

    Sánchez-Azofeifa, Arturo; Garvin, Theresa; Benoit-Rivard., Benoit; Gamon, John; Schnitzer, Stefan; Lawrence, Deborah; Quesada, Mauricio; Stoner, Kathryn E.; Castillo, Alicia; Rodríguez, Jon Paul; Nassar, Jafet M.; Capote, Rene; Fernandes, Geraldo W.; De Espirito-Santo, Marcos; Menezes, Rómulo

    2014-01-01

    Código VIE: 5402-1401-1012 Este proyecto se encadenó al proyecto ya concluido "Dimensiones humanas, ecológicas y biofísicas de los bosques secos tropicales (código VIE 5402-1401-9001)". Durante su ejecución fue posible dar continuidad al análisis de datos y preparación de publicaciones científicas y académicas pendientes como fenología, dinámica de hojarasca, tasas de crecimiento, mortalidad y reingreso en el bosque seco tropical. También el proyecto trabajo en la preparación de artículos ...

  19. Thermoregulatory, Cardiovascular, and Metabolic Responses to Mild Caloric Restriction in the Brown Norway Rat

    Science.gov (United States)

    Caloric restriction (CR) has been demonstrated to prolong the life span of a variety of species. CR-induced reduction in core temperature (Tc) is considered a key mechanism responsible for prolonging life span in rodents; however, little is known on the regulation of CR-induced h...

  20. Biochemical composition and caloric potential of zooplankton from Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Sreepada, R.A.; Rivonker, C.U.; Parulekar, A.H.

    .62, 4.95, 1.54, 0.43, 4.4 and 4.16 respectively on wet weight basis. A good correlation of caloric potential with protein and lipid indicated to a certain extent that protein and lipid act as metabolic reserves of the zooplankton in the area...

  1. Effects of Caloric Restriction on Cardiac Oxidative Stress and Mitochondrial Bioenergetics: Potential Role of Cardiac Sirtuins

    Directory of Open Access Journals (Sweden)

    Ken Shinmura

    2013-01-01

    Full Text Available The biology of aging has not been fully clarified, but the free radical theory of aging is one of the strongest aging theories proposed to date. The free radical theory has been expanded to the oxidative stress theory, in which mitochondria play a central role in the development of the aging process because of their critical roles in bioenergetics, oxidant production, and regulation of cell death. A decline in cardiac mitochondrial function associated with the accumulation of oxidative damage might be responsible, at least in part, for the decline in cardiac performance with age. In contrast, lifelong caloric restriction can attenuate functional decline with age, delay the onset of morbidity, and extend lifespan in various species. The effect of caloric restriction appears to be related to a reduction in cellular damage induced by reactive oxygen species. There is increasing evidence that sirtuins play an essential role in the reduction of mitochondrial oxidative stress during caloric restriction. We speculate that cardiac sirtuins attenuate the accumulation of oxidative damage associated with age by modifying specific mitochondrial proteins posttranscriptionally. Therefore, the distinct role of each sirtuin in the heart subjected to caloric restriction should be clarified to translate sirtuin biology into clinical practice.

  2. Caloric variability of Corbicula fluminea (Mollusca, Bivalvia in Rosana Reservoir, Brazil

    Directory of Open Access Journals (Sweden)

    Yara Moretto Bagatini

    2007-01-01

    Full Text Available The purpose of the present study was to investigate temporal and longitudinal variation of caloric density of Corbicula fluminea in Rosana Reservoir. Significant differences concerning the caloric density of C. fluminea were observed throughout the year at the three reservoir sites. The caloric density variation during the year was probably related to reproductive activity, which demanded higher allocation of energy in certain period. The food source used by this species might be an important factor in the caloric value temporal and spatial variation of C. fluminea in Rosana Reservoir.O objetivo deste estudo foi investigar a variação temporal e longitudinal da densidade calórica de C. fluminea no reservatório de Rosana. Diferenças significativas na densidade calórica de C. fluminea foram observadas ao longo do ano e nas três estações do reservatório. A variação na densidade calórica de C. fluminea, durante o ano, provavelmente foi relacionada à atividade reprodutiva, que exige uma maior alocação de energia em determinado período. O recurso alimentar utilizado por esta espécie pode ser um importante fator na variação temporal e espacial do valor calórico de C. fluminea no reservatório de Rosana.

  3. Benefits of caloric restriction in the myenteric neuronal plasticity in aging rats

    Directory of Open Access Journals (Sweden)

    JOICE N.B. PEREIRA

    2014-09-01

    Full Text Available Aging is a biologic process characterized by progressive damage of structures and functions of organic systems. In gastrointestinal tract, it can involve enteric nervous system, which plays an important role in digestion and absorption of nutrients, causing hastening of intestinal transit thus reducing its absorptive function. Caloric restriction has been used in several studies with the intention of delaying deleterious effects of aging. This study aimed to evaluate the effects of caloric restriction on myenteric neurons of ileum by aging in rats. 30 Wistar rats were grouped as follows: GI (animals aged 6 months fed with normal diet, GII (animals aged 18 months fed with normal diet and GIII (animals aged 18 months subject to 31% of caloric restriction. The rats of the GI group were euthanized at 6 months of age and after experimental period of 12 months animals of the group GII and GIII were euthanized, the ileum of all groups were collected, measured and processed by NADPH-dp and Acetylcholinesterase. Quantitative analysis of neurons revealed that aging promotes the increasing of myenteric neurons NADPH-dp and reduces Acetylcholinesterase neuronal population. However, in the cellular profile area, were not observed significant differences between the groups. The caloric restriction has been efficient and can be used preventively because it minimizes quantitative changes associated with aging on ileum myenteric plexuses.

  4. Benefits of caloric restriction in the myenteric neuronal plasticity in aging rats.

    Science.gov (United States)

    Pereira, Joice N B; Mari, Renata B; Stabille, Sandra R; de Faria, Haroldo G; Mota, Thais F M; Ferreira, Walter M

    2014-09-01

    Aging is a biologic process characterized by progressive damage of structures and functions of organic systems. In gastrointestinal tract, it can involve enteric nervous system, which plays an important role in digestion and absorption of nutrients, causing hastening of intestinal transit thus reducing its absorptive function. Caloric restriction has been used in several studies with the intention of delaying deleterious effects of aging. This study aimed to evaluate the effects of caloric restriction on myenteric neurons of ileum by aging in rats. 30 Wistar rats were grouped as follows: GI (animals aged 6 months fed with normal diet), GII (animals aged 18 months fed with normal diet) and GIII (animals aged 18 months subject to 31% of caloric restriction). The rats of the GI group were euthanized at 6 months of age and after experimental period of 12 months animals of the group GII and GIII were euthanized, the ileum of all groups were collected, measured and processed by NADPH-dp and Acetylcholinesterase. Quantitative analysis of neurons revealed that aging promotes the increasing of myenteric neurons NADPH-dp and reduces Acetylcholinesterase neuronal population. However, in the cellular profile area, were not observed significant differences between the groups. The caloric restriction has been efficient and can be used preventively because it minimizes quantitative changes associated with aging on ileum myenteric plexuses.

  5. Restauración en el Inmunoblotting de proteínas de Neisseria meningitidis dañadas por calor y agentes reductores

    Directory of Open Access Journals (Sweden)

    Rolando Ochoa

    2015-12-01

    Full Text Available En este trabajo se utilizaron cinco detergentes para restaurar las proteínas de membrana externas (PME del meningococo dañadas por el efecto del calor y de agentes reductores utilizados en el Inmunoblotting. La acción de los detergentes fue evaluada en la solución de lavado, en el diluente de la muestra y del conjugado. Las bandas de proteínas, reconocidas por la IgG del suero, fueron identificadas usando un conjugado anti IgG humana peroxidasa. Los antígenos reconocidos por el control positivo se corresponden con las proteínas P1, P3, P4 y P5 atendiendo a su peso molecular. Además, fueron reconocidas bandas de 80, 70, 24 kDa y otra con peso mayor a 150 kDa. En general el reconocimiento de todas las PME, excepto esta última de alto peso molecular (APM, se vieron favorecidas con la utilización del Tween 20, con el que se logró un incremento del número y la intensidad de las bandas así como la disminución de los fondos con respecto al resto de detergentes evaluados (Empigen BB, Triton X-100, Nonidet NP-40 y CHAPS. El reconocimiento de la proteína de APM (>150 kDa se vio afectado por la presencia de detergente como el Tween 20 y Empigen BB. Los lavados con Tween 20 constituyeron los pasos más importantes en la renaturalización de los sitios de unión de la IgG a las PME

  6. Déficit de polinização da aceroleira no período seco no semiárido paraibano

    Directory of Open Access Journals (Sweden)

    Rozileudo da Silva Guedes

    2011-06-01

    Full Text Available A aceroleira é uma importante frutífera tropical que pode produzir frutos o ano todo na região semiárida do Nordeste do Brasil, caso seja utilizada a irrigação. Como a aceroleira depende da polinização por abelhas coletoras de óleos florais para apresentar uma produção satisfatória de frutos, este trabalho teve como objetivo avaliar a abundância de polinizadores e o sucesso reprodutivo da cultura no período seco, no semiárido paraibano. Foram registradas quatro espécies de abelhas nativas da tribo Centridini, todas consideradas polinizadoras efetivas da aceroleira, pela frequência nas flores e comportamento: Centris aenea Lepeletier, C. tarsata Smith, C. fuscata Lepeletier e C. trigonoides Lepeletier (Apidae, Centridini. A frequência de visitas às flores foi menor no período seco do que no período chuvoso. A polinização cruzada manual complementar resultou em incremento de 61 a 74% na produção de frutos durante o período seco, nos dois anos avaliados, indicando que há um grande déficit de polinização devido à baixa abundância de abelhas Centris. Esse resultado implica a necessidade de manejo dos polinizadores, especialmente em cultivos irrigados durante o período seco, na região semiárida do Nordeste do Brasil.

  7. Proyecto de Docencia y Pedagogía acerca de plantas medicinales presentes en Colombia que se utilizan de manera rutinaria en la Medicina Tradicional China para drenar calor

    OpenAIRE

    Bueno Bedoya, María Amelia

    2014-01-01

    La Medicina Tradicional China (MTCh) tiene varios arsenales terapéuticos, entre ellos está la herbolaria. En el país se encuentran de manera natural algunas de las plantas que utiliza la herbolaria china, entre ellas aquellas que se utilizan para drenar calor. Los médicos que ejercen la MTCh en el país tienen poca información acerca de esta área del conocimiento. Sin embargo es de gran importancia ampliarla y hacerla práctica con el fin de tratar de manera más integral y eficie...

  8. Análisis de aprovechamiento de calores residuales de los gases de escape del motor térmico mediante efecto Seebeck en una unión Cu-Al

    OpenAIRE

    Fernández Juncà, Joan

    2014-01-01

    El presente documento pretende estudiar la posibilidad de recuperar parte de la energía térmica expulsada (calor residual) por un motor térmico, en su paso por el sistema de escape. Analizar la viabilidad de poder cargar baterías y/o alimentar sistemas electrónicos del vehículo, a partir del flujo térmico de los gases de escape. Se pretende analizar con detalle el flujo térmico así como los efectos electromagnéticos asumibles en un transformador de una sola espira de sección gene...

  9. Validación de dos métodos analíticos: calor de combustión y azufre, en materiales combustibles que pueden ser quemados en hornos de clinker

    Directory of Open Access Journals (Sweden)

    Karen Hooker

    2010-10-01

    Full Text Available Se validaron dos métodos para llevar a cabo la evaluación fisicoquímica de materiales de desecho de diferentes empresas interesadas en tratar sus residuos, para utilizarlos como combustible alternativo para un horno de cemento, que calcina estos materiales a una temperatura máxima de 2000°C. Con este fin se optimizaron las figuras de mérito de la determinación del calor de combustión y del porcentaje de azufre.

  10. Analytical model to describe the thermal behavior of a heat discharge system in roofs; Modelo analitico que describe el comportamiento termico de un sistema de descarga de calor en techos

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Gomez, V.H.; Contreras-Espinosa, J.J.; Gonzalez-Ortiz, G.; Morillon-Galvez, D.; Fernandez-Zayas, J.L. [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)]. E-mail: vichugo@servidor.unam.mx; jjuancon2000@yahoo.com.mx; gilberto_gonzalez25@hotmail.com; damg@pumas.iingen.unam.mx; JFernandezZ@iingen.unam.mx

    2012-01-15

    The present study proposes an analytical model which describes the thermal behavior of a heat discharge system in roof, when the surfaces that constitute it are not translucent. Such a model derives from a thermal balance carried out to a heat discharge system in roofs. To validate it, an experimental prototype that allows simulating the thermal behavior of a heat discharge system in wall and roof was used, and the results were compared to those obtained with the proposed analytical model. It was found that the thermal behavior of the analytical model is similar to the thermal behavior of the experimental prototype; a worthless variation was detected among their respective outcome (The difference of temperatures can be caused by the heat transfer coefficient, of which no studies defining its behavior accurately have been found). Therefore, it can be considered that the proposed analytical model can be employed to simulate the thermal behavior of a heat discharge system in roofs when the surfaces that constitute it are opaque. [Spanish] En el presente estudio se propone un modelo analitico que describe el comportamiento termico de un sistema de descarga de calor en techo, cuando las superficies que lo componen no son translucidos. Dicho modelo surge a partir de un balance termico realizado a un sistema de descarga de calor en techos. Para validarlo, se realizaron dos corridas experimentales en un prototipo que permite simular el comportamiento termico de un sistema de descarga de calor en techo y se compararon los resultados medidos con los calculados por el modelo analitico propuesto. Se encontro que, el comportamiento termico del modelo analitico es similar al comportamiento termico del prototipo experimental, se detecto una variacion despreciable entre los valores arrojados por ambos modelos (la diferencia de temperaturas puede estar ocasionada por la obtencion del coeficiente convectivo de transferencia de calor, del cual no se han encontrado estudios que

  11. Variação sazonal do fluxo de calor no solo dentro de um manguezal tropical Seazonal variation of soil heat flux within tropical mangrove

    Directory of Open Access Journals (Sweden)

    Marcos A. L. Moura

    2010-03-01

    Full Text Available Os manguezais são ecossistemas de grande importância em virtude da sua biodiversidade, embora ainda pouco estudados. O fluxo de calor no solo (FCS é uma propriedade que interfere no microclima de um ecossistema e depende de vários fatores. Um estudo experimental foi realizado em um manguezal no município de Marechal Deodoro, Alagoas, no período de outubro/2004 a outubro/2005, com o objetivo de caracterizar a variação sazonal do FCS; para isto, uma estação meteorológica automática foi montada em uma torre micrometeorológica para registrar diferentes elementos do tempo e clima, de forma contínua. Especificamente, para medição do FCS a 10 cm de profundidade utilizou-se uma bateria de três fluxímetros modelo HFT3 (Campbell Scientific, EUA no sentido de que a interferência da não uniformidade do solo nas medições fosse minimizada. Os resultados obtidos demonstraram influência da radiação solar, precipitação e da maré sobre a variação diária e sazonal do FCS, além de grande diferença de amplitude diária do FCS entre os períodos chuvoso (9 W m-2 e seco (36 W m-2.Mangrove swamps are highly important ecosystems due to their biodiversity, but they still are little studied. Soil heat fluxes (SHF is one of the proprieties that interfere in the ecosystem microclimate and depends on lots of factors. An experimental study was carried out in a mangrove forest in the Marechal Deodoro city, in the State of Alagoas, from October/2004 to October/2005, with the aim of describing the SHF seasonal variation. To this end, an automatic weather station was assembled in a micrometeorological tower to register the data continuously. To measure SHF in 10 cm depth one battery with three (3 fluximeter model HFT3 (Campbell Scientific, EUA was used so that the soil uniformity interference in the measurements was reduced. The obtained results showed influence of solar radiation, rainfall and tidal wave in the daily and seasonal SHF variation. A

  12. D-seco-Vitamin D analogs having reversed configurations at C-13 and C-14: Synthesis, docking studies and biological evaluation.

    Science.gov (United States)

    Szybinski, Marcin; Sokolowska, Katarzyna; Sicinski, Rafal R; Plum, Lori A; DeLuca, Hector F

    2017-10-01

    Prompted by results of molecular modeling performed on the seco-d-ring-vitamins D, we turned our attention to such analogs, having reversed configurations at C-13 and C-14, as the next goals of our studies on the structure-activity relationship for vitamin D compounds. First, we developed an efficient total synthesis of the "upper" C/seco-d-ring fragment with a 7-carbon side chain. Then, we coupled it with A-ring fragments using Sonogashira or Wittig-Horner protocol, providing the targeted D-seco analogs of 1α,25-dihydroxyvitamin D 3 and 1α,25-dihydroxy-19-norvitamin D 3 possessing a vinyl substituent at C-14 and a double bond between C-17 and C-20. The affinities of the synthesized vitamin D analogs to the full-length recombinant rat VDR were examined, as well as their differentiating and transcriptional activities. In these in vitro tests, they were significantly less active compared to 1α,25-(OH) 2 D 3 . Moreover, it was established that the analogs tested in vivo in rats showed no calcemic potency. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. The comparative effect of fasting with and without caloric restriction in Rat on oxidative stress parameters

    Directory of Open Access Journals (Sweden)

    Nurina Tyagita

    2016-09-01

    Full Text Available Introduction: Fasting, like Islamic Ramadan Fasting, has been associated with health benefits. Islamic Ramadan fasting, a form of caloric restriction (CR or alternate day fasting that. Studies suggest a comparable effect of ADF and caloric restriction. Despite the fact that fasting can be considered as a form of dietary restriction, fasters tend to have difficulty to reduce their food intake during non-fasting period by overeating leading to the excessive calorie intake. To compare the effect of fasting with and without caloric restriction in Sprague Dawley rats. Methods: The rats were assigned to one of three groups: ADF with 70 % calorie intake (30% CR, ADF with 100 % calorie intake (0% CR, and ADF with 140 % calorie intake (excessive calorie intake and AL (fed ad libitum. All groups were subjected to 6 hour fasting per day (9 a.m. until 3 p.m. or 15 days. The plasma sample was taken for MDA level assessment. Urinary 8-oxodG levels were determined by using ELISA. Results: ADF with 30% calorie restriction (F70 group had the lowest MDA level. Measurement of 8-oxodG level showed that group F70 had the highest production of 8-oxodG. There was an inverse relationship between MDA level and 8-oxodG level meaning the lower MDA level, the lower 8-oxodG levels were produced. Conclusion: ADF fasting with 30% caloric restriction reduce the MDA level but increase 8-oxodG levels. This study suggest the beneficial effect of fasting requires decrease in overall caloric intake.

  14. [Comparison of caloric responses between vestibular migraine and Ménière disease patients].

    Science.gov (United States)

    Yang, Yuechang; Zhuang, Jianhua; Zhou, Lili; Tong, Bei; Zhou, Xiaowen; Gao, Bo

    2016-01-01

    To compare the features of caloric tests in vestibular migraine (VM) and Menière's disease (MD) patients, and provide objective evidence for differentiating the 2 groups of patients. This case-control study included 11 MD patients with left ear involved and mild to moderate impaired hearing, and 18 matched cases with VM. All participants received caloric tests. Maximum slow phase velocities (SPVmax) were used to describe horizontal and vertical nystagmus respectively and were compared between the 2 groups. Horizontal and vertical canal parasis(CP) were calculated according to respective SPVmax. Unilateral (UW-VR) or bilateral (BW-VR) weakness of vestibular response, and positive unilateral (UVR) or bilateral (BVR) vertical response or negative bilateral vertical response (NBVR) were judged by the boundary point of SPVmax of 5°/s respectively. Total left (LV) or right (RV) Vertical reactions were calculated accoeding to vertical SPVmax,and inter ears difference of vertical responses (IED-VR) calculated from LV minus RV. There were no significant differences in age and gender between the 2 groups. Horizontal SPVmax of all of caloric tests of VM group,except the left cold (LC), were statistically larger than that of MD group (P VR and BW-VR in VM group (5.56%, 0) were significantly lower than that in MD group (27.27%, 18.18%) (P VR in VM group (left intenser: 16.67%, right intenser: 83.33%) was statistically different from that in MD group (left intenser: 36.36%, right intenser: 9.09%, both no difference: 54.55%) (P Vestibular responses of caloric test are more sensitive, and vertical reactions are more easily induced in VM patients than in MD. Caloric test can be used to differentiate the 2 groups of diseases.

  15. Focos de Calor na Mata Atlântica do Estado do Rio de Janeiro

    Directory of Open Access Journals (Sweden)

    Sara dos Santos Clemente

    Full Text Available Resumo O estudo avaliou a ocorrência de focos de calor nos remanescentes da Mata Atlântica no estado do Rio de Janeiro, sob o aspecto climático. As informações obtidas da base de dados BDQueimadas, do período de junho de 1998 a dezembro de 2015, sofreram estatística descritiva, exploratória e paramétrica. As maiores ocorrências de focos de calor foram registradas nos meses de agosto, setembro e outubro e, os anos com os maiores registros foram nos ciclos 2010/2011 (16,06% e 2014/2015 (41, 24%, ambos somaram 57,30% da série temporal, referente a La Niña e El Niño nas categorias forte e fraco. O teste paramétrico mostrou uma repetição dos meses de abril e junho nos anos avaliados na série temporal de focos de calor. As regiões de Governo Centro-Sul Fluminense e Médio Paraíba registraram os maiores registros de focos de calor, segundo a avaliação espacial. Nossos resultados demonstram que o acesso a uma base gratuita de dados permite a prevenção de danos causados pelas queimadas e incêndios. Com a evolução dos sensores de temperatura e de algoritmos de tratamento de dados, será possível diferenciar os focos de calor que representam incêndios e queimadas daqueles que indicam, por exemplo, atividade de indústrias.

  16. MORFOGÊNESE DE Trachypogon vestitus SUBMETIDO À QUEIMA, DURANTE O PERÍODO SECO, NOS CERRADOS DE RORAIMA

    Directory of Open Access Journals (Sweden)

    Newton de Lucena Costa

    2012-03-01

    Full Text Available O efeito da idade de rebrota (21, 28, 35, 42, 49, 56, 63 e 70 dias sobre a produção de forragem e características morfogênicas e estruturais de Trachypogon vestitus, submetido à queima, durante o período seco, foram avaliados em condições de campo. O delineamento experimental foi inteiramente casualizado com três repetições. As avaliações foram realizadas no período de dezembro de 2009 a fevereiro de 2010. O aumento da idade de rebrota resultou em maiores rendimentos de matéria seca (MS, taxa absoluta de crescimento (TAC, número de perfilhos/planta (NPP, número de folhas/perfilho (NFP, tamanho médio de folhas (TMF, área foliar e taxas de expansão e senescência foliar (P<0,05. As relações entre idades de rebrota, rendimento de MS, TAC, NPP, NFP e TMF da gramínea foram ajustadas ao modelo quadrático de regressão, sendo os valores máximos registrados aos 64,8; 42,3; 59,6; 61,8 e 59,4 dias de rebrota, respectivamente. As taxas de crescimento da cultura, taxa de crescimento relativo, taxas de aparecimento de perfilhos e de folhas foram inversamente proporcionais às idades das plantas.

  17. El ecoturismo como alternativa sostenible para proteger el bosque seco tropical peruano: El caso de Proyecto Hualtaco, Tumbes

    Directory of Open Access Journals (Sweden)

    Pedro Gonzáles Mantilla

    2015-01-01

    Full Text Available El bosque seco tropical peruano es un ecosistema de alto valor endémico, de riqueza biológico - - cultural y belleza paisajística, que viene siendo amenazado por los conflictos sociales y el manejo irresponsable de sus recursos. Proyecto Hualtaco es una concesión de conservación dentro de este entorno, distinguida por su localización estratégica e importancia científica. Allí se realizó una evaluación del potencial ecoturístico cuyos resultados fueron utilizados para la construcción de una propuesta de desarrollo ecoturístico que permita reconciliar la conservación del patrimonio natural y el desarrollo económico local. Se esbozaron cuatro zonas de uso dentro de la concesión. Se plantearon cinco estrategias para el desarrollo ecoturístico, a través de 33 actividades, programadas en un plazo de dos años. Finalmente, se delinearon diez mecanismos para la generación de ingresos y 28 indicadores de manejo y monitoreo del ecoturismo, elementos claves para el éxito de la propuesta.

  18. Análisis comparativo del aprendizaje de los conceptos de calor y temperatura utilizando una simulación digital interactiva y un texto ilustrado

    Directory of Open Access Journals (Sweden)

    Cimenna Chao Rebolledo

    2014-06-01

    Full Text Available Esta investigación analizó las diferencias que subyacen al aprendizaje de los conceptos de calor y temperatura en relación a los conceptos de energía térmica y energía cinética, a través de dos modalidades instruccionales: mediante la lectura de un texto ilustrado y a través de una simulación digital interactiva. Se trabajó con alumnos de dos grados escolares : 48 alumnos de segundo de secundaria sin instrucción previa sobre dichos fenómenos y 48 alumnos de tercero de secundaria con conocimientos académicos previos sobre los temas revisados. Se observaron diferencias significativas en la resolución de problemas asociados a los conceptos estudiados siendo mejor el desempeño de los participantes que utilizaron la simulación digital interactiva durante el aprendizaje y significativamente mejor en los alumnos con instrucción previa sobre dichos conceptos. El desempeño de los grupos que utilizaron el texto ilustrado fue significativamente mejor que su contraparte en problemas orientados a la definición literal de los fenómenos estudiados.

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

    OpenAIRE

    A. Batista Cabrera; U. Ordoñez Hernández

    1999-01-01

    En el siguiente trabajo se describe una tecnología de desulfuracíon del hierro fundido gris, tomando como base el ya conocidométodo de Volianik (1). En este caso se modificaron algunos parámetros del citado método, adecuándolos a las condicionesexistentes en la Empresa de Fundición de Hierro y Acero de Holguín.( E.F. H. A.)Como agente desulfurante se empleó carburo de calcio empleado por Volianik. Como agente activador del desulfurante seutilizó aire comprimido seco. El desulfurante con la gr...

  20. Beneficial Effects of Caloric Restriction on Chronic Kidney Disease in Rodent Models: A Meta-Analysis and Systematic Review.

    Science.gov (United States)

    Xu, Xiao-Meng; Cai, Guang-Yan; Bu, Ru; Wang, Wen-Juan; Bai, Xue-Yuan; Sun, Xue-Feng; Chen, Xiang-Mei

    2015-01-01

    Numerous studies have demonstrated the life-extending effect of caloric restriction. It is generally accepted that caloric restriction has health benefits, such as prolonging lifespan and delaying the onset and progression of CKD in various species, especially in rodent models. Although many studies have tested the efficacy of caloric restriction, no complete quantitative analysis of the potential beneficial effects of reducing caloric intake on the development and progression of CKD has been published. All studies regarding the relationship between caloric restriction and chronic kidney diseases were searched in electronic databases, including PubMed/MEDLINE, EMBASE, Science Citation Index (SCI), OVID evidence-based medicine, Chinese Bio-medical Literature and Chinese science and technology periodicals (CNKI, VIP, and Wan Fang). The pooled odds ratios (OR) and 95% confidence intervals (95% CI) were calculated by using fixed- or random-effects models. The data from 27 of all the studies mentioned above was used in the Meta analysis. Through the meta-analysis, we found that the parameter of blood urea nitrogen, serum creatinine and urinary protein levels of the AL group was significant higher than that of the CR group, which are 4.11 mg/dl, 0.08mg/dl and 33.20mg/kg/24h, respectively. The incidence of the nephropathy in the caloric restriction (CR) group was significantly lower than that in the ad libitum-fed (AL) group. We further introduced the subgroup analysis and found that the effect of caloric restriction on the occurrence of kidney disease was only significant with prolonged intervention; the beneficial effects of CR on the 60%-caloric-restriction group were greater than on the less-than-60%-caloric-restriction group, and caloric restriction did not show obvious protective effects in genetically modified strains. Moreover, survival rate of the caloric restriction group is much higher than that of the ad libitum-fed (AL) group. Our findings demonstrate for the

  1. Beneficial Effects of Caloric Restriction on Chronic Kidney Disease in Rodent Models: A Meta-Analysis and Systematic Review.

    Directory of Open Access Journals (Sweden)

    Xiao-Meng Xu

    Full Text Available Numerous studies have demonstrated the life-extending effect of caloric restriction. It is generally accepted that caloric restriction has health benefits, such as prolonging lifespan and delaying the onset and progression of CKD in various species, especially in rodent models. Although many studies have tested the efficacy of caloric restriction, no complete quantitative analysis of the potential beneficial effects of reducing caloric intake on the development and progression of CKD has been published.All studies regarding the relationship between caloric restriction and chronic kidney diseases were searched in electronic databases, including PubMed/MEDLINE, EMBASE, Science Citation Index (SCI, OVID evidence-based medicine, Chinese Bio-medical Literature and Chinese science and technology periodicals (CNKI, VIP, and Wan Fang. The pooled odds ratios (OR and 95% confidence intervals (95% CI were calculated by using fixed- or random-effects models.The data from 27 of all the studies mentioned above was used in the Meta analysis. Through the meta-analysis, we found that the parameter of blood urea nitrogen, serum creatinine and urinary protein levels of the AL group was significant higher than that of the CR group, which are 4.11 mg/dl, 0.08mg/dl and 33.20mg/kg/24h, respectively. The incidence of the nephropathy in the caloric restriction (CR group was significantly lower than that in the ad libitum-fed (AL group. We further introduced the subgroup analysis and found that the effect of caloric restriction on the occurrence of kidney disease was only significant with prolonged intervention; the beneficial effects of CR on the 60%-caloric-restriction group were greater than on the less-than-60%-caloric-restriction group, and caloric restriction did not show obvious protective effects in genetically modified strains. Moreover, survival rate of the caloric restriction group is much higher than that of the ad libitum-fed (AL group.Our findings

  2. Video head-impulse test (vHIT) in dizzy children with normal caloric responses.

    Science.gov (United States)

    Khater, Ahmed Mohammed; Afifi, Pretty O

    2016-08-01

    The caloric test and the video head-impulse test are diagnostic tools to examine dizzy patients through assessing the function of the semicircular canals. There are major differences between the two tests as regards stimulus characteristics, methodology, and function examined. The aim of this study is to evaluate the results of vHIT in children and adolescents with normal caloric test. This work was performed on 63 patients, but 14 were excluded because of technical problems in the caloric test. So, this is a prospective work in 49 patients (27 females and 22 males) with different types of vestibular disease seen because of vertigo in which both procedures were performed the same day. The caloric test was performed with air at two different temperatures in which both ears were irrigated alternately. Then, the video head-impulse test was carried out. Main outcome measures were the gain of vestibulo-ocular reflex, gain asymmetry, and refixation saccades in the vHIT. in all studied cases, caloric test was normal. The mean age of patients was 16 years. By vHIT, in 8 patients (16%) no abnormality was detected, while abnormal findings were found in 41 patients. Single canal affection was seen in 29 patients whereas 12 patients had combined canal affection. The right side was affected in 27 and left side in 22 patients. In single canal affection, isolated horizontal canals were affected in 4, anterior canals in 5 and posterior canals in 20 patients. While in combined canal affection, the affection is seen in the same ear. Moreover the most common pattern seen is affection of left anterior and left posterior canals. The caloric and vHIT is very important tests in diagnosis of dizzy patients. The information from both methods is redundant in some cases but complementary in most. vHIT is a "child friendly," relatively easy-to-use, and simple tool to evaluate each of the 6 semicircular canals. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  3. Beneficios de la equinoterapia en niños con TEA

    OpenAIRE

    Prieta Cuervo, Jazmina de la

    2017-01-01

    RESUMEN El propósito fundamental de este trabajo es conocer los beneficios que la equinoterapia aporta a los niños con TEA en lo que a habilidades sociales y comunicativas se refiere, así como al lenguaje y las áreas cognitivas y psicológicas. Todo ello, mediante la realización de actividades con caballos que sirven como herramienta principal, ya que la transmisión de calor corporal, los movimientos tridimensionales y las vibraciones que transmite el caballo al niño van a proporcionar estimul...

  4. Estimación del agua corporal total y del peso seco usando impedancia bioeléctrica tetrapolar de multifrecuencia en pacientes en hemodiálisis. Universidad Nacional de Colombia, Unidad Renal Fundación Hospital San Carlos, Cruz Roja y Centro de Investigación

    Directory of Open Access Journals (Sweden)

    Doris Ramirez de Peña

    2015-01-01

    Full Text Available En la búsqueda de métodos confiables y sencillos para la medición de la composición corporal de los pacientes renales en hemodiálisis (HD y, particularmente, del agua total corporal (TBW, se ha utilizado la bioimpedancia tetrapolar de unifrecuencia (BIA-1 y, más recientemente, la bioimpedancia tetrapolar de multifrecuencia, (BIA-4 como métodos confiables a utilizar en pacientes renales. Es necesario conocer el agua total corporal y el peso seco lo más acertadamente posible, puesto que con ellos se determina el tratamiento dialítico, farmacológico y nutricional de los pacientes renales en hemodiálisis. Por esta razón, se realizó un estudio clínico controlado no aleatorizado en seis fases, desde el año 2001 al 2010, en el que participaron estudiantes de pregrado del Programa de Nutrición y Dietética de la Universidad Nacional de Colombia, profesores de la Facultad de Medicina de la misma Universidad y el equipo de nefrólogos y nutricionistas de las unidades renales de la Fundación Hospital San Carlos, de la Cruz Roja y del Centro de Investigación de Enfermedades Crónicas de Bogotá, con el fin de establecer la confiabilidad del método, determinar una ecuación para conocer el agua total corporal de pacientes renales en HD colombianos, determinar un punto de corte utilizando la resistencia de la BIA para monitorear la cantidad de agua aumentada  interdiálisis de los pacientes, la presencia de síntomas, y conocer la utilidad de la normovolemia en la obtención del peso seco. Se encontró -al igual que en otros estudios- que la BIA-4 multifrecuencia es un método que ofrece enormes posibilidades en el estudio del paciente renal, al ser sensible a los cambios de la composición corporal del individuo, además de ser un método sencillo, indoloro, no invasivo y de fácil ejecución que permite establecer el peso seco, el estado nutricional, el agua extra e intracelular, la masa magra, la masa grasa, etc. También se logr

  5. Is the caloric curve a robust signal of the phase transition in hot nuclei?

    Science.gov (United States)

    Vient, E.

    2017-11-01

    The richness of the data set, collected by the INDRA Collaboration during the last twenty years, enabled us to build a set of caloric curves for nuclei of various sizes, by using, for the first time, a single experimental set-up and a single experimental protocol. We will therefore present the different caloric curves ( E^{\\ast}-T obtained by a new calorimetry, for Quasi-Projectiles produced by symmetric or quasi symmetric reactions at different incident energies (Au + Au, Xe + Sn, Ni + Ni). For all these systems, a clear change of the de-excitation process of hot nuclei is observed but this one is neither a plateau nor a back-bending, but a sudden change of slope.

  6. Transferência de calor no escoamento turbulento em desenvolvimento entre placas planas paralelas

    OpenAIRE

    Marcio Bueno dos Santos

    1991-01-01

    O presente trabalho tem por finalidade a análise experimental do problema de convecção forçada entre placas paralelas no escoamento com transição laminar-turbulento, com condições assimétricas do perfil de temperatura. A determinação dos valores locais dos coeficientes de transferência de calor é obtida aplicando-se a técnica se Sublimação de Naftaleno. De acordo com a analogia entre transferência de calor e transferência de massa as condições experimentais correspondem a situação de transfer...

  7. Caloric Intake From Fast Food Among Children and Adolescents in the United States, 2011-2012.

    Science.gov (United States)

    Vikraman, Sundeep; Fryar, Cheryl D; Ogden, Cynthia L

    2015-09-01

    Consumption of fast food has been linked to weight gain in adults (1). Fast food has also been associated with higher caloric intake and poorer diet quality in children and adolescents (2). From 1994 through 2006, caloric intake from fast food increased from 10% to 13% among children aged 2-18 years (3). This report presents the most recent data on the percentage of calories consumed from fast food among U.S. children by sex, age group, race and Hispanic origin, poverty status, and weight status. All material appearing in this report is in the public domain and may be reproduced or copied without permission; citation as to source, however, is appreciated.

  8. Current and future employment of the heat pumps; Pompe di calore. Presente e futuro

    Energy Technology Data Exchange (ETDEWEB)

    Cassitto, L. [Milan Politecnico, Milan (Italy). Dipt. di Energetica

    2001-12-01

    Heat pumps, mainly the compression type, grant high energy savings together with environment protection because of the free low temperature energy from environment or wasted heat they use. Their large employment depends on the appreciation of the above properties that are will be done. To grant economic savings on using heat pumps, electric energy and natural gas should have fixed and predictable prices. [Italian] Le pompe di calore, in particolare quelle a compressione, hanno elevate prestazioni energetiche e ambientali, grazie all'utilizzo di fonti di calore gratuite a bassa temperatura, naturali o residue di altri processi. La loro diffusione e' legata alla percezione di queste potenzialita' rinunciando alle caldaie tradizionali. Sono indispensabili prezzi dell'energia elettrica e del metano stabili e comunque prevedibili per garantire anche la loro convenienza economica.

  9. Caloric restriction in lean and obese strains of laboratory rat: effects on body composition, metabolism, growth and overall health

    Data.gov (United States)

    U.S. Environmental Protection Agency — Data related to obese and lean strains of rat commonly used in the laboratory that are calorically restricted and its effects on physiologic parameters (Body...

  10. Effects of Moderate Aerobic Exercise Combined With Caloric Restriction on Circulating Estrogens and IGF-I in Premenopausal Women

    National Research Council Canada - National Science Library

    Williams, Nancy I

    2004-01-01

    ... the primary prevention of breast cancer in women. This study has examined the effects of exercise training combined with caloric restriction, resulting in weight loss, on two hormonal biomarkers for breast cancer i.e...

  11. Caloric Vestibular Stimulation Reduces Pain and Somatoparaphrenia in a Severe Chronic Central Post-Stroke Pain Patient: A Case Study

    National Research Council Canada - National Science Library

    Spitoni, Grazia Fernanda; Pireddu, Giorgio; Galati, Gaspare; Sulpizio, Valentina; Paolucci, Stefano; Pizzamiglio, Luigi

    2016-01-01

    .... To date, there is limited evidence for the effective treatments of this disease. Here we used caloric vestibular stimulation to reduce pain and somatoparaphrenia in a 57-year-old woman suffering from central post-stroke pain...

  12. Comportamiento del desgaste del flanco en el torneado en seco de alta velocidad del acero AISI 316L//Flank wear behavior in the dry high‐speed turning of AISI 316L stainless steel

    Directory of Open Access Journals (Sweden)

    Yoandrys Morales-Tamayo

    2013-09-01

    Full Text Available El presente estudio experimental se centra en investigar los efectos de los parámetros corte en el desgaste de flanco con dos insertos recubiertos durante el torneado de acabado en seco a altas velocidades del acero inoxidable AISI 316L. Los efectos de los parámetros de corte fueron determinados utilizando un análisis de varianza y de regresión simple. Como principal resultado se obtuvo el efectosignificativo del avance y del tiempo de maquinado en el desgaste del flanco. El inserto de tres capas no sobrepasó el criterio de fin de vida del desgaste, mientras que el inserto de una capa sufrió un desgaste catastrófico para la mayor velocidad de corte. El desgaste del flanco tuvo mejor comportamiento para el avance de 0,08 mm/rev en todas las velocidades empleadas en este estudio.Palabras claves: torneado de alta velocidad, desgaste de flanco, acero inoxidable AISI 316L, estudio experimental, análisis de varianza y regresión.______________________________________________________________________________AbstractThe current experimental study is focused on investigating the effects of cutting parameters on flank wear in two coated carbide inserts during dry high speed finish turning of AISI 316L stainless steel. The effects of cutting parameters were determinate using analysis of variance and simple regression. As a main resulta significant effect of cutting feed and the machining time on flank wear was found. The three coating layers insert did not exceed the criterion of end of life of wear while the insert with one layer suffered a catastrophic wear at the highest cutting speed. The flank wear showed the best performance for the cuttingfeed of 0,08 mm/rev at all the speeds used in the study.Key words: high speed turning; flank wear; AISI 316L stainless steel, experimental study; analysis of variance and regression.

  13. Análise da transferência de calor em paredes compostas por diferentes materiais

    Directory of Open Access Journals (Sweden)

    Luciano Pivoto Specht

    Full Text Available O projeto de edificações energeticamente eficientes necessita de conhecimentos sobre a transferência de calor proveniente do ambiente externo, a fim de criar soluções que associem diferentes materiais e espessuras às condições desejadas de conforto térmico. O objetivo deste trabalho é avaliar diversos tipos e disposições de materiais em paredes de tijolos maciços, sob a ótica da térmica de edifícios. Para a realização dos experimentos, modelos em escala real foram confeccionados, instrumentados e acoplados a uma câmara térmica, desenvolvida especialmente para esse fim. O problema de transferência de calor foi modelado pela equação da energia, resolvida em Diferenças Finitas Centrais, utilizando-se o Método Implícito. As difusividades térmicas dos materiais foram calculadas resolvendo o Problema Inverso de transferência de calor. Também foi calculado o fluxo de calor e o custo total de cada alternativa, finalizando-se com a obtenção da relação termoeconômica para cada parede. Através da análise termoeconômica pode-se constatar que, apesar de o investimento inicial ser relativamente maior nas paredes mais espessas e/ou com isolamento térmico, estas apresentam um comportamento térmico muito superior às tradicionais. Notadamente, a parede com EPS na face exterior apresentou o melhor desempenho.

  14. Caloric Value of Some Forest Fuels of the Southern United States

    Science.gov (United States)

    Walter A. Hough

    1969-01-01

    The caloric value of a variety of southern forest fuels was determined in an oxygen bomb calorimeter. High heat values ranged between about 3,600 and 5,200 cal./g. for fuels as sampled and between 4,500 and 5,600 cal./g. for fuels on an ash-free basis. Additional tests of forest fuels from the Southern, Eastern, and North Central United States showed a...

  15. Caloric beverages were major sources of energy among children and adults in Mexico, 1999-2012.

    Science.gov (United States)

    Stern, Dalia; Piernas, Carmen; Barquera, Simon; Rivera, Juan A; Popkin, Barry M

    2014-06-01

    Mexico, with 1 of the highest obesity prevalences in the world, instituted a 10% excise tax for any sugar-sweetened beverage (SSB) starting on 1 January 2014. Understanding the recent patterns and trends in beverage intake and sales in Mexico provides both background and baseline data for the importance of SSBs and other beverages in the Mexican diet. We analyzed a single 24-h dietary recall from 2 nationally representative surveys: the Mexican Nutrition Survey 1999 (n = 6049) and the National Health and Nutrition Survey 2012 (n = 10,343). To describe trends and patterns in beverages, we calculated the volume and energy intake per capita and per consumer and the proportion of consumers of each beverage group in each survey. A commercial sales dataset was used to describe beverage sales trends from 1999 to 2012. From 1999 to 2012, total daily energy from beverages increased among children aged 5-11 y (+45.3 kcal), females aged 12-19 y (+57.3 kcal), and adult females aged 20-49 y (+96.4 kcal) (P total daily energy intake per capita in children aged 1-19 y and adults aged ≥20 y, respectively. In 2012, flavored milk beverages, caloric soda, and high-fat milk were the top 3 major contributors to total daily energy intake per capita in all children aged 1-19 y. Caloric soda, caloric coffee/tea, and agua fresca were the top 3 major energy contributors in adults aged ≥20 y. From 1999 to 2012, sales of soda, fruit-flavored drinks, and flavored waters increased. In conclusion, consumption of several beverages with added sugars increased among children and adult females in Mexico. Because caloric soda is currently 1 of the top beverages consumed, a 10% tax on SSBs might help to significantly reduce added sugars intake in Mexico. © 2014 American Society for Nutrition.

  16. Caloric compensation in preschool children: Relationships with body mass and differences by food category.

    Science.gov (United States)

    Carnell, S; Benson, L; Gibson, E L; Mais, L A; Warkentin, S

    2017-09-01

    Maintaining a healthy weight may involve compensating for previously consumed calories at subsequent meals. To test whether heavier children demonstrated poorer caloric compensation across a range of conditions, and to explore whether compensation failure was the result of inadequate adjustment of overall intake or specific over-consumption of highly palatable, high energy-density 'junk' foods, we administered two compensation tests to a sample of 4-5 y olds. For Test A, preloads varied only in carbohydrate content and were organoleptically indistinguishable (200 ml orange-flavored beverage [0 kcal vs. 200 kcal]). For Test B, the preloads varied substantially in both macronutrient composition and learned gustatory cues to caloric content (200 ml water [0 kcal] vs. 200 ml strawberry milkshake [200 kcal]). Each preload was followed 30 min later by a multi-item ad-libitum meal containing junk foods (chocolate cookies, cheese-flavored crackers) and core foods (fruits and vegetables, bread rolls, protein foods). Testing took place at the children's own school under normal lunch-time conditions. Children were weighed and measured. Caloric compensation occurred in both tests, in terms of total, junk and core food intake (RMANOVA, all p junk food intake (RMANOVA preload-by-weight group interaction p effect for core foods. Our results suggest that caloric compensation is consistently poorer in heavier children, and that overweight/obese children's preferences for junk foods may overwhelm intake regulation mechanisms within meals containing those foods. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Influence of Caloric Vestibular Stimulation on Body Experience in Healthy Humans

    OpenAIRE

    Andreas eSchönherr; Christian-Albrecht eMay

    2016-01-01

    The vestibular system has more connections with and influence on higher cortical centers than previously thought. These interactions with higher cortical centers and the phenomena that they elicit require a structural intact cerebral cortex. To date, little is known about the role and influence of the vestibular system on one’s body experience. In this study we show that caloric vestibular stimulation (CVS) in healthy participants has an effect on the perceptive component of one’s body experi...

  18. Shifts in the Distribution of Mass Densities Is a Signature of Caloric Restriction in Caenorhabditis elegans

    OpenAIRE

    Alfonso Reina; Anand Bala Subramaniam; Anna Laromaine; Aravinthan D T Samuel; Whitesides, George M.

    2013-01-01

    Although the starvation response of the model multicellular organism Caenorhabditis elegans is a subject of much research, there is no convenient phenotypic readout of caloric restriction that can be applicable to large numbers of worms. This paper describes the distribution of mass densities of populations of C. elegans, from larval stages up to day one of adulthood, using isopycnic centrifugation, and finds that density is a convenient, if complex, phenotypic readout in C. elegans. The dens...

  19. Comparison of caloric and head-impulse tests during the attacks of Meniere's disease.

    Science.gov (United States)

    Lee, Sun-Uk; Kim, Hyo-Jung; Koo, Ja-Won; Kim, Ji-Soo

    2017-03-01

    To aid in diagnosis of Meniere's disease (MD) during the attacks using caloric and head-impulse tests (HITs). Retrospective case series review. We analyzed the results of bithermal caloric and HITs during the attacks in 16 patients with MD. Quantitative analyses of HITs were conducted using a magnetic search coil technique. In unilateral MD (14 patients, 42 semicircular canals), the head impulse gain of the vestibulo-ocular reflex (VOR) was either normal (28 of 42, 67%), decreased (8 of 42, 19%), or increased (6 of 42, 14%) for each semicircular canal in the affected ear. Likewise, the head impulse VOR gain was either normal (29 of 42, 69%), increased (11 of 42, 26%), or decreased (2 of 42, 5%) in the intact ear. The VOR gain for the horizontal canal was significantly lower on the affected side (P = 0.013). However, the VOR gains for the anterior and posterior canals did not differ between the sides (P = 0.270, P = 0.282). In bilateral MD (two patients, 12 semicircular canals), the VOR gain was either decreased (6 of 12, 50%) or normal (6 of 12, 50%) in either ear. In contrast, the caloric responses were usually decreased in the affected ear (7 of 11, 64%, including one with bilateral MD). During the attacks of MD, HITs showed varied results between the ears and among the canals, although the caloric responses were usually decreased in the involved ear. These dissociations suggest a frequency-dependent impairment of canal function or mechanical property of the endolymphatic hydrops during the attacks of MD. 4. Laryngoscope, 127:702-708, 2017. © 2016 The American Laryngological, Rhinological and Otological Society, Inc.

  20. Adipose-immune interactions during obesity and caloric restriction: reciprocal mechanisms regulating immunity and health span

    OpenAIRE

    Dixit, Vishwa Deep

    2008-01-01

    Increasing evidence suggests a tight coupling of metabolic and immune systems. This cross-talk mediated by neuroendocrine peptides as well as numerous cytokines and chemokines is believed to be responsible for integrating energy balance to immune function. These neuroendocrine-immune interactions are heightened during the state of chronic positive energy balance, as seen during obesity, and negative energy balance caused by caloric restriction (CR). Emerging evidence suggests that obesity may...

  1. Pudrición basal causada por Phytophthora capcisi en plantas de chile tratadas con vermicompost

    Directory of Open Access Journals (Sweden)

    Lidieth Uribe-Lorío

    2014-07-01

    Full Text Available El objetivo de este trabajo fue evaluar a nivel de invernadero el efecto de vermicompost sobre la incidencia y severidad de Phytophthora capcisi en plantas de chile (Capsicum annuum. Esta investigación se realizó entre febrero y marzo del 2012 en el Centro de Investigaciones Agronómicas, Sabanilla, San José, Costa Rica. Se utilizó un diseño completamente al azar con cuatro repeticiones y ocho plantas por unidad experimental en un arreglo factorial con los factores de dosis (0, 25% y 50% v/v vermicompost:suelo e inoculación (0 y 500 zoosporas por gramo de suelo. Se trasplantaron plántulas de 35 días, que fueron inoculadas dos semanas después del trasplante. La aplicación de vermicompost provocó un aumento significativo del peso fresco foliar y del peso seco foliar y radical; a mayor dosis, mayor fue el incremento. Las plantas de todos los tratamientos que incluyeron inoculación con P. capsici presentaron síntomas de la enfermedad en la raíz. Los valores de incidencia y severidad fueron mayores para el tratamiento con 50% de abono. En este tratamiento se presentaron síntomas de marchitez. La ausencia de diferencias en las variables de peso fresco y seco entre los tratamientos inoculados y sin inocular, a los que se adicionó abono al 25%, sugiere que esta dosis podría compensar el daño causado por el patógeno. Se observó una menor concentración de nutrimentos en los tejidos de las plantas inoculadas lo que indica que el daño causado a la raíz pudo haber afectado la adquisición de nutrimentos.

  2. Effects of caloric deprivation and satiety on sensitivity of the gustatory system

    Directory of Open Access Journals (Sweden)

    Zverev Yuriy P

    2004-02-01

    Full Text Available Abstract Background Sensitivity of the gustatory system could be modulated by a number of short-term and long-term factors such as body mass, gender, age, local and systemic diseases and pathological processes, excessive alcohol drinking, drug dependence, smoking, composition of oral fluid, state of oral hygiene, consumption of some foods among many others. A few studies have demonstrated the effects of hunger and caloric satiety on sensitivity of the gustatory system in obese humans and animals. The aim of the present study was to assess the effects of short-term caloric deprivation and satiety on recognition taste thresholds of healthy, non-smoking, non-drinking, non-obese young male subjects. The two-alternative forced-choice technique was used to measure taste threshold. Results Recognition thresholds for sucrose and salt were significantly lower during fasting state than after a meal (t = 2.23, P Conclusions Short-term caloric deprivation in our study model was associated with increased taste sensitivity to sweet and salty substances compared to satiated state while taste sensitivity to bitter substances was not affected by the conditions of measurements. Selective modulation of sensitivity of the gustatory system might reflect the different biological importance of salty, sweet and bitter qualities of taste.

  3. Importance of silvopastoral systems on caloric stress reduction in tropical livestock productions

    Directory of Open Access Journals (Sweden)

    Alexander Navas Panadero

    2010-06-01

    Full Text Available Livestock systems in Colombia have been developed taking concepts and technologies from the green revolution, where gramineous monocrop is privileged over arboreal cover in grazing lands. This model has not taken into account the climatic conditions of the different tropical ecosystems, in which variables as temperature, relative humidity and evaporation can limit the animal´s productive and reproductive efficiency, besides being a risk factor for illness occurrence in the herd. Bos Taurus and Bos Indicus breeds show termoneutral ranges where its genetic potential can be express. However, out of this comfort area animals can enter in caloric stress which in consequence reduces its performance and sometimes can end up causing death. Silvopastoral systems comprise several functions; it contributes to lessen caloric stress since temperature under the tree canopy can reach between 2 and 9°C lower in comparison to open pastures. Differences in temperature reduction have been found among silvopastoral systems and species, being the tree group arrangements and the species with high density canopy, those with superior effect. Interactions among components should be analyzed in order to design systems that incorporate enough arboreal cover to achieve caloric stress reductions, but without affecting forage production in pastures. Silvopastoral systems contribute to improve animal welfare.

  4. CALOR2012 XVth International Conference on Calorimetry in High Energy Physics

    Energy Technology Data Exchange (ETDEWEB)

    Akchurin, Nural .

    2015-05-04

    The International Conferences on Calorimetry in High Energy Physics, or the CALOR series, have always been where the calorimeter experts come together to review the state of calorimetry and bring forth new ideas every two years. The fteenth conference, CALOR2012, in Santa Fe was no exception. Although they were built roughly a decade ago, we are now witnessing the exceptional power of the LHC calorimeters and the crucial role they have been playing in the discovery of the 125 GeV Higgs-like boson. As we ruminate on the coming generation of experiments at the next (linear) collider and on the upgrades at the LHC, we are heartened by the substantial advances we made in calorimetry in the last decade. These advances will certainly help uncover new physics in the years to come, not only at colliders but also in astroparticle experiments that take advantage of natural elements such as air, water, and ice. The proceedings were published by the IOP in Journal of Physics, Vol 404 2011. The conference web site is calor2012.ttu.edu.

  5. Normal physical activity obliterates the deleterious effects of a high-caloric intake.

    Science.gov (United States)

    Krogh-Madsen, Rikke; Pedersen, Maria; Solomon, Thomas P J; Knudsen, Sine Haugaard; Hansen, Louise Seier; Karstoft, Kristian; Lehrskov-Schmidt, Louise; Pedersen, Karin Kaereby; Thomsen, Carsten; Holst, Jens Juul; Pedersen, Bente K

    2014-02-01

    A high-caloric intake combined with a sedentary lifestyle is an important player in the development of type 2 diabetes mellitus (T2DM). The present study was undertaken to examine if the level of physical activity has impact on the metabolic effects of a high-caloric (+2,000 kcal/day) intake. Therefore, healthy individuals on a high-caloric intake were randomized to either 10,000 or 1,500 steps/day for 14 days. Step number, total energy expenditure, dietary records, neuropsychological tests, maximal oxygen uptake (Vo2max), whole body dual-energy X-ray absorptiometry (DXA) and abdominal magnetic resonance imaging (MRI) scans, continuous glucose monitoring (CGM), and oral glucose tolerance tests (OGTT) with stable isotopes were performed before and after the intervention. Both study groups gained the same amount of body weight. However, the inactive group accumulated significantly more visceral fat compared with the active group. Following the 2-wk period, the inactive group also experienced a poorer glycemic control, increased endogenous glucose production, decreased hepatic insulin extraction, increased baseline plasma levels of total cholesterol and LDL, and a decreased cognitive function with regard to capacity of attention. In conclusion, we find evidence to support that habitual physical activity may prevent pathophysiological symptoms associated with diet-induced obesity.

  6. Peripheral ghrelin enhances sweet taste food consumption and preference, regardless of its caloric content.

    Science.gov (United States)

    Disse, Emmanuel; Bussier, Anne-Lise; Veyrat-Durebex, Christelle; Deblon, Nicolas; Pfluger, Paul T; Tschöp, Matthias H; Laville, Martine; Rohner-Jeanrenaud, Françoise

    2010-09-01

    Ghrelin is one of the most potent orexigens known to date. While the prevailing view is that ghrelin participates in the homeostatic control of feeding, the question arose as to whether consummatory responses evoked by this compound could be related to search for reward. We therefore attempted to delineate the involvement of ghrelin in the modulation of non-caloric but highly rewarding consumption. We tested the effect of intraperitoneally injected ghrelin on the acceptance and preference for a 0.3% saccharin solution using single bottle tests and free-choice preference test procedures in C57BL6/J mice, as well as in mice lacking the ghrelin receptor (GHSR1a -/-) and their wild-type (WT) littermates. In the single bottle tests, peripheral ghrelin consistently increased the consumption of saccharin, independently of availability of caloric food. In the free-choice preference test procedures, ghrelin increased the preference for saccharin in WT mice, while it did had not effect in GHSR1a -/-animals, indicating that the ghrelin receptor pathway is necessary to mediate this parameter. Peripheral ghrelin enhances intake and preference for a sweet food, regardless of whether the food has caloric content. This effect, mediated through the ghrelin receptor pathway, may serve as additional enhancers of energy intake. Copyright 2010 Elsevier Inc. All rights reserved.

  7. Weight cycling and cancer: weighing the evidence of intermittent caloric restriction and cancer risk.

    Science.gov (United States)

    Thompson, Henry J; McTiernan, Anne

    2011-11-01

    Overweight and obese individuals frequently restrict caloric intake to lose weight. The resultant weight loss, however, typically is followed by an equal or greater weight gain, a phenomenon called weight cycling. Most attention to weight cycling has focused on identifying its detrimental effects, but preclinical experiments indicating that intermittent caloric restriction or fasting can reduce cancer risk have raised interest in potential benefits of weight cycling. Although hypothesized adverse effects of weight cycling on energy metabolism remain largely unsubstantiated, there is also a lack of epidemiologic evidence that intentional weight loss followed by regain of weight affects chronic-disease risk. In the limited studies of weight cycling and cancer, no independent effect on postmenopausal breast cancer but a modest enhancement of risk for renal cell carcinoma, endometrial cancer, and non-Hodgkin's lymphoma have been reported. An effect of either intermittent caloric restriction or fasting in protecting against cancer is not supported by the majority of rodent carcinogenesis experiments. Collectively, the data argue against weight cycling and indicate that the objective of energy balance-based approaches to reduce cancer risk should be to strive to prevent adult weight gain and maintain body weight within the normal range defined by body mass index.

  8. Temas de Física para Ingeniería: Temperatura y propagación del calor

    OpenAIRE

    Beléndez Vázquez, Augusto

    1992-01-01

    Acústica, fluidos y termodinámica: "Temperatura y propagación del calor". Introducción. Descripciones macroscópica y microscópica de un sistema. Equilibrio térmico y principio cero de la termodinámica. Termómetros y escala de temperaturas del gas ideal. Dilatación térmica. Propagación del calor.

  9. Análisis de la máxima intensidad de la isla de calor urbana nocturna de la ciudad de Rancagua (Chile y sus factores explicativos.

    Directory of Open Access Journals (Sweden)

    Pablo Sarricolea

    2008-12-01

    Full Text Available Las ciudades constituyen el hábitat por excelencia de los seres humanos, y pese a su diversidad presentan características ambientales (clima urbano comunes en muchas partes del mundo, como por ejemplo la presencia de la Isla de Calor Urbana (ICU, que corresponde a un aumento de origen antrópico de las temperaturas de la ciudad en comparación con su entorno inmediato de carácter natural y rural, siendo más intensa dicha diferencia en las noches. Por ello, el propósito de esta investigación es analizar la Máxima Intensidad de la Isla de Calor Urbana (MIICU de Rancagua a partir de mediciones de las temperaturas con transectos móviles y estaciones meteorológicas fijas. Se ha determinado que la máxima intensidad de la isla de calor urbana de Rancagua bordea los 6°C en verano y primavera, y 3°C para invierno y otoño. Los factores que explican las distribuciones de las temperaturas urbanas de Rancagua corresponden a las distancias a fuentes húmedas (río Cachapoal y las densidades poblacionales; y en menor medida las características topográficas del emplazamiento de la ciudad y las áreas verdes urbanas medidas a partir del índice normalizado de diferencias vegetales (NDVI. La principal conclusión de esta investigación indica que la ausencia de parques urbanos en Rancagua explica la distribución de las temperaturas y la elevada intensidad de la isla de calor, y también la no significativa relación entre temperaturas y NDVI. De no revertirse esta situación, la sostenibilidad ambiental futura de la ciudad de Rancagua se verá muy amenazada por el crecimiento urbano.Cities are the environment for excellence in human beings, and despite their diversity, environmental features (urban climate are common in many parts of the world, such as the presence of the Urban Heat Island (UHI. This corresponds to a temperature increase due to human activities in the city compared with its immediate natural and rural surroundings, the difference

  10. Method to allow the estimation of heat transfer coefficients in solar stills; Metodo para determinar coeficientes locales de transferencia de calor en destiladores solares

    Energy Technology Data Exchange (ETDEWEB)

    Rubio Cerda, Eduardo; Porta Gandara, Miguel A [CIBNOR, Mexico D.F (Mexico); Fernandez Zayas, Jose Luis [UNAM Mexico, D.F. (Mexico)

    2000-07-01

    This work reports an experimental method that allows to estimate the heat transfer coefficients in the neighborhood of walls or flat plates subject to convective transport phenomena. This method can be applied to a great variety of thermal systems since it is based on the knowledge of the border condition for the temperature at the surface of the plate, and the temperature profile that characterize the dimensionless coefficient of heat transfer in the fluid, according to its definition given by the Nusselt number. The approach of this work are the foundations of the method and the system that has been developed to apply it, that incorporates automatic acquisition equipment for continuos monitoring of the information and elements to control the parameters of interest. In addition, the experimental cavities on which the method will be evaluated are discussed, considering two different scales, as well as experiments in cavities filled with air, and with a mixture of air and steam water, as is the case for solar distillation. [Spanish] En este trabajo se presenta un metodo que permite determinar de manera experimental coeficientes de transferencia de calor por conveccion. Este metodo puede ser aplicado a una gran variedad de sistemas termicos ya que se fundamenta en el conocimiento de la condicion de frontera para la temperatura en la superficie de la placa, y del perfil de temperaturas que caracteriza el coeficiente adimensional de transferencia de calor en el fluido, de acuerdo a la definicion de este, dada por el numero de Nusselt. El trabajo que aqui se reporta esta enfocado a la fundamentacion del metodo y al equipamiento que se ha desarrollado para instrumentarlo, que incorpora equipos automaticos de adquisicion continua de informacion y elementos de control para los parametros de interes. Se presentan ademas, las cavidades experimentales sobre las que sera evaluado el metodo, que considera dos escalas diferentes, asi como experimentos en cavidades llenas de aire

  11. EVALUACIÓN DE LA PLANTA Lemna minor COMO BIORREMEDIADORA DE AGUAS CONTAMINADAS CON MERCURIO

    Directory of Open Access Journals (Sweden)

    Adolfo D. Arenas

    2011-01-01

    Full Text Available Se evaluó la capacidad biorremediadora de Lemna minor en función del tiempo en aguas contaminadas con mercurio mediante un diseño experimental de 3 bloques al azar con cinco réplicas: un grupo experimental con 100 g de Lemna, 7,5 L de agua contaminada con Hg (0,13 mgL-1 y solución nutritiva; un grupo Testigo con 100 g de Lemna, 7,5 L de agua y solución nutritiva y un grupo control con mercurio al nivel de 0,13 mgL-1 en agua destilada sin plantas. La eficiencia de remoción de mercurio de la Lemna minor, en 22 días, fue de 30%. Las variables peso fresco, peso seco, y nitrógeno y fósforo foliares no presentaron diferencias significativas entre los dos tratamientos. La absorción de potasio, fue afectada por los niveles de mercurio. La planta Lemna minor representa una alternativa para la remoción de mercurio en aguas contaminadas hasta un nivel de 0,13 mg/L.

  12. Rationale for anti-inflammatory therapy in dry eye syndrome Bases da terapia antiinflamatória em síndrome do olho seco

    Directory of Open Access Journals (Sweden)

    CS De Paiva

    2008-12-01

    Full Text Available Dry eye is a multifactorial condition that results in a dysfunctional lacrimal functional unit. Evidence suggests that inflammation is involved in the pathogenesis of the disease. Changes in tear composition including increased cytokines, chemokines, metalloproteinases and the number of T cells in the conjunctiva are found in dry eye patients and in animal models. This inflammation is responsible in part for the irritation symptoms, ocular surface epithelial disease, and altered corneal epithelial barrier function in dry eye. There are several anti-inflammatory therapies for dry eye that target one or more of the inflammatory mediators/pathways that have been identified and are discussed in detail.Olho seco é uma doença multifatorial que resulta em disfunção da unidade lacrimal glandular. Evidências sugerem que inflamação está involvida na patogênese da doença. Mudanças na composição das lágrimas, incluindo aumento de citocinas, quimiocinas, metaloproteinases e o número de células T na conjuntiva são encontrados em pacientes com olho seco e em modelos animais. Esta inflamação é responsável em parte pelos sintomas de irritação, doença epitelial de surperfície ocular e função epitelial de barreira alterada em olho seco. Existem várias terapias antiinflamatórias que se direcionam para um ou mais mediadores/vias que foram identificados e são discutidos em detalhe.

  13. Comportamento higroscópico do extrato seco de urucum (Bixa Orellana L Hygroscopic behavior of annatto (Bixa Orellana L dried extract

    Directory of Open Access Journals (Sweden)

    George Carlos dos Santos Anselmo

    2008-12-01

    Full Text Available Neste trabalho, objetivou-se determinar a higroscopicidade do urucum na forma de extrato seco. Neste estudo foram obtidas as atividades de água do extrato seco de urucum para as temperaturas de 10 a 50ºC e teores de água entre 6 e 22% base úmida. A metodologia empregada para as determinações foi o método dinâmico em que se utilizou o equipamento Thermoconstanter Novasina TH-2. Para os resultados experimentais aplicaram-se as equações propostas por Henderson modificada por Thompson e Henderson modificada por Cavalcanti Mata e Peleg. Por meio das análises dos parâmetros encontrados concluiu-se que a equação que melhor se ajusta aos dados experimentais é a equação de Henderson modificada por Cavalcanti Mata e que as isotermas de adsorção de água do extrato de urucum seco se comportaram sigmoidalmente, sendo consideradas do tipo II.The objective of this work was to verify the higroscopicity of annatto seeds in the dry extract form. The isotherms were determined by the dynamic method with the Thermoconstanter Novasina TH-2 equipment. The equilibrium temperatures were 10, 20, 30, 40 and 50 ºC to range of moisture content between 6 and 22%, wet basis. The equations proposed by Henderson modified by Thompson and Henderson modified by Cavalcanti Mata and Peleg were applied to the experimental data. Through the gotten parameters found concluded that the best equation to represent the experimental data is the Henderson equations modified by Cavalcanti Mata. It was also concluded that hygroscopic equilibrium isotherms of annatto seeds presented sigmoid forms, considered type II.

  14. Two New 3,4;9,10-seco-Cycloartane Type Triterpenoids from Illicium difengpi and Their Anti-Inflammatory Activities

    Directory of Open Access Journals (Sweden)

    Chuntong Li

    2013-01-01

    Full Text Available A pair of new 3,4;9,10-seco-cycloartane type triterpenoid stereoisomerides: 24R,25-dihydroxy-3,4;9,10-seco-4(28-cycloarten-10,3-olide (1 named Illiciumolide A and 24S,25-dihydroxy-3,4;9,10-seco-4(28-cycloarten-10,3-olide (2 named Illiciumolide B were isolated from the stem bark of Illicium difengpi, as well as five known biogenetically related triterpenoids, including sootepin E (3, betulinic acid (4, lupeol (5, (all-Z-1,5,9,13,17,21-hexamethyl-1,5,9,13,17,21-cyclotertracosahexaene (6, and (all-E-2,6,10,15,19,23-hexamethyl-2,6,10,14,18,22-tetracosahexaene (7. The structures of two new compounds were determined on the basis of spectroscopic analysis including 1D-, 2D-NMR, and MS techniques. Two assays were conducted: inhibition of tumor necrosis factor-alpha (TNF-α and inhibition of nuclear factor kappa B (NF-κB in RAW264. 7 cells induced by lipopolysaccharide (LPS. It was observed that compounds 1, 2 and 7 showed significant inhibition of TNF-α production and NF-κB release. The molecule docking results showed that compounds 1 and 2 got high fitness scores with dual specificity mitogen-activated protein kinase kinase 1 (MPKK1, whose activation plays a pivotal role between TNF-α and activation of NF-κB. The anti-HIV-1 potency of compounds 1–5 was also discussed, in addition to the results of computer-aided screening for targets.

  15. Caloric Beverages Were Major Sources of Energy among Children and Adults in Mexico, 1999–2012123

    Science.gov (United States)

    Stern, Dalia; Piernas, Carmen; Barquera, Simon; Rivera, Juan A.; Popkin, Barry M.

    2014-01-01

    Mexico, with 1 of the highest obesity prevalences in the world, instituted a 10% excise tax for any sugar-sweetened beverage (SSB) starting on 1 January 2014. Understanding the recent patterns and trends in beverage intake and sales in Mexico provides both background and baseline data for the importance of SSBs and other beverages in the Mexican diet. We analyzed a single 24-h dietary recall from 2 nationally representative surveys: the Mexican Nutrition Survey 1999 (n = 6049) and the National Health and Nutrition Survey 2012 (n = 10,343). To describe trends and patterns in beverages, we calculated the volume and energy intake per capita and per consumer and the proportion of consumers of each beverage group in each survey. A commercial sales dataset was used to describe beverage sales trends from 1999 to 2012. From 1999 to 2012, total daily energy from beverages increased among children aged 5–11 y (+45.3 kcal), females aged 12–19 y (+57.3 kcal), and adult females aged 20–49 y (+96.4 kcal) (P agua fresca (fruit water made in stalls or at home, usually with added sugars), and fruit drinks among children aged 5–11 y and females aged 12–19 y and caloric coffee/tea, soda, and agua fresca among adult females aged 20–49 y. In 2012, beverages represented 17.5% (325 kcal) and 19.0% (382 kcal) of the total daily energy intake per capita in children aged 1–19 y and adults aged ≥20 y, respectively. In 2012, flavored milk beverages, caloric soda, and high-fat milk were the top 3 major contributors to total daily energy intake per capita in all children aged 1–19 y. Caloric soda, caloric coffee/tea, and agua fresca were the top 3 major energy contributors in adults aged ≥20 y. From 1999 to 2012, sales of soda, fruit-flavored drinks, and flavored waters increased. In conclusion, consumption of several beverages with added sugars increased among children and adult females in Mexico. Because caloric soda is currently 1 of the top beverages consumed, a 10% tax

  16. Procedimiento para la dispersión de nanopartículas en seco y la obtención de estructuras jerárquicas y recubrimientos

    OpenAIRE

    Fernández Lozano, José Francisco; Lorite, Israel; Rubio Marcos, Fernando; Romero Fanego, Juan José; García García-Tuñón, Miguel Ángel; Quesada, Adrián; Martín-González, Marisol S.; Costa Krämer, José Luis

    2008-01-01

    Procedimiento para la dispersión de nanopartículas en seco y la obtención de estructuras jerárquicas y recubrimientos. La presente invención se refiere a un procedimiento para la dispersión de nanopartículas sintéticas o naturales y de materiales nanocompuestos, y sus aplicaciones en diferentes sectores, entre los que destacan los sectores de cerámica, de recubrimientos, de polímeros, de la construcción, de pinturas, de catálisis, farmacéutico o de materiales pulverule...

  17. DIVERSIDAD, COMPOSICIÓN FLORÍSTICA Y ENDEMISMOS EN LOS BOSQUES ESTACIONALMENTE SECOS ALTERADOS DEL DISTRITO DE JAÉN, PERÚ

    OpenAIRE

    Marcelo-Peña, José Luis; Universidad Nacional Agraria La Molina (Perú).; Reynel-Rodríguez, Carlos; Universidad Nacional Agraria La Molina (Perú).; Zevallos-Pollito, Percy; Universidad Nacional Agraria La Molina (Perú).; Bulnes-Soriano, Fernando; Universidad Nacional Agraria La Molina (Perú).; Pérez-Ojeda del Arco, Alonso; Universidad Nacional Agraria La Molina (Perú).

    2007-01-01

    Mediante el establecimiento de 40 transectos siguiendo la metodología de Gentry, se realizó un análisis de la diversidad, endemismos, composición florística y complementariamente la estructura de la vegetación leñosa de bosques estacionalmente secos (BTES) alterados de cuatro sectores del distrito de Jaén. Las familias más abundantes son Boraginaceae, Leguminosae, Malvaceae y Cactaceae; los géneros más abundantes son Cordia, Tetrasida, Esenbeckia y Browningia. Las especies más importantes son...

  18. Evaluación nutricional de arbóreas y arbustivas de bosque muy seco tropical (bms- T) en producción bovina

    OpenAIRE

    Edmundo Apráez; Arturo Leonel Gálvez; Jorge Fernando Navia

    2017-01-01

    Se determinó la calidad nutricional de las arbóreas Payandé (Pithecellobium lanceolatum MART.), Guácimo (Guazuma ulmifolia LAM.), Caña fístula (Cassia fistula L.), Chiminango (Pithecellobium dulce MART.) y Samán (Samanea saman JACQ.) en zona de bosque muy seco tropical (bms-T) del Valle del Patía y el efecto como suplemento en la alimentación de bovinos mestizos tipo cebú. Se evaluaron seis tratamientos: T0 (100% pastoreo), T1(90% pastoreo +10% P. lanceolatum); T2 (90% pastoreo +10% P.dulce);...

  19. INFILTRAÇÃO DE DIFERENTES SUBSTÂNCIAS OU AGULHAMENTO À SECO EM DOR MIOFASCIAL UMA REVISÃO SISTEMÁTICA

    OpenAIRE

    Eduardo Machado

    2015-01-01

    A dor miofascial temporomandibular apresenta um grande desafio diagnóstico dentro das Disfunções Temporomandibulares. Devido às características dessa condição, procedimentos de infiltração intramuscular muitas vezes são necessários para o adequado controle e tratamento dos sintomas. Assim, o objetivo desse estudo é avaliar a efetividade de infiltrações com diferentes substâncias ou agulhamento à seco em dor miofascial temporomandibular. O delineamento do estudo consistiu em ...

  20. Determinación de los costos energéticos y de explotación del sistema de cultivo del arroz en seco

    OpenAIRE

    Pedro Paneque Rondón; Alexander Miranda Caballero; Natali Abraham Ferro; Meibi Suárez Gómez

    2009-01-01

    Como parte de las investigaciones dirigidas al desarrollo sostenible de la agricultura, que se llevan a cabo en el Centro de Mecanización Agropecuaria (CEMA) y a petición de la granja Cubanacán perteneciente al Complejo Agroindustrial (CAI) Arrocero "Los Palacios", en la provincia de Pinar del Río, se plantea el objetivo de este trabajo, que consiste en determinar los costos energético y de explotación del sistema de cultivo del arroz en seco, en las principales operaciones mecanizadas de lab...

  1. Al calor de la masculinidad. Clima, migración y normativas de género en la Costa de Hermosillo, Sonora

    Directory of Open Access Journals (Sweden)

    José Eduardo Calvario Parra

    2017-01-01

    Full Text Available En este estudio sobre migrantes jornaleros(as agrícolas en la Costa de Hermosillo, Sonora, se presenta una primera aproximación analítica y descriptiva respecto a la relación entre clima y masculinidad en el noroeste de México. A través de un enfoque metodológico cualitativo, por medio de entrevistas semiestructuradas y observaciones de campo, se explora el vínculo entre las normativas masculinas y las prácticas o discursos relacionados con el cuidado ante el calor natural excesivo. La conclusión es que las condiciones de vulnerabilidad estructural que viven los/as trabajadores/as agrícolas están acompañadas con ideologías de género, que en situaciones determinadas se vuelven cruciales para tomar la decisión de cuidarse de las temperaturas altas o de no hacerlo.

  2. Simulación numérica en Ingeniería y Ciencias con MATLAB + COMSOL Multiphysics

    OpenAIRE

    Ivorra, Benjamin

    2015-01-01

    En este seminario se tratan las posibles interacciones entre el entorno de programación matricial MATLAB y el software COMSOL Multiphysics, que permite resolver de forma intuitiva sistemas de ecuaciones en derivadas parciales con diversas implementaciones del método de los elementos finitos. Este tipo de ecuaciones modelan los fenómenos correspondientes a los problemas de mecánica de fluidos, transferencia de calor, electromagnetismo, etc. La posibilidad del uso combinado es importante, en pa...

  3. Composição química do óleo fixo obtido dos frutos secos da [Chamomilla recutita (L. Rauschert] produzida no município de Mandirituba, PR.

    Directory of Open Access Journals (Sweden)

    N.P. Pereira

    Full Text Available A camomila [Chamomilla recutita (L. Rauschert], é uma planta empregada na indústria de medicamentos, cosméticos e alimentos. Os frutos secos da camomila conhecidos por "sementes" são provenientes dos capítulos florais, dos quais pode-se extrair um óleo fixo rico em ácidos graxos insaturados. Através da técnica de extração com hexano em dispositivo de soxhlet, foi obtido o óleo bruto dos frutos secos da camomila em 19% de rendimento. O óleo foi caracterizado pela técnica de CG-EM, revelando um elevado teor de ácido linoleico na sua composição. Portanto, o óleo oriundo dos frutos secos da camomila vem a ser uma matéria-prima potencialmente útil na dermo-farmácia.

  4. Extrato seco total de vinhos brasileiros: comparação de métodos analíticos Total dry extract in Brazilian wines: comparison of analytical methods

    Directory of Open Access Journals (Sweden)

    Luiz Antenor Rizzon

    1996-08-01

    Full Text Available A legislação brasileira não estabelece limites para o extrato seco total dos vinhos, mas determina valores máximos para a relação álcool em peso/extrato seco reduzido. Até 1985, o extrato seco total era determinado pela pesagem do resíduo seco (método direto, causando problemas de enquadramento à legislação brasileira, principalmente os vinhos tintos finos. A partir de 1986, o extrato seco total passou a ser feito pelo método indireto. Esta metodologia analítica, acrescida da modificação na legislação, alterando os valores máximos da relação álcool em peso/extrato seco reduzido permitiu que, de um modo geral, os vinhos se enquadrassem à legislação. Face a isso, procurou-se comparar os dois métodos para vinhos finos secos e comuns secos e suaves; tintos, brancos e rosados. Os resultados mostraram que o método indireto originou valores do extrato seco total para os vinhos secos, em média 2,1 g/l significativamente maiores em relação ao método direto. Mas o efeito não foi significativo para os suaves. Tendo em vista os valores de extrato seco total dos vinhos encontrados pelo atual método oficial, não se justificam os atuais limites máximos na legislação da relação álcool em peso/extrato seco reduzido, por serem excessivamente elevados.Brazilian legislation does not establish limits for the total dry extract of wines, but it establishes maximum values for the ratio between weight alcohol and reduced dry extract. Until 1985 the total dry extract was determined by weighting the dry residue (direct method, which caused several problems for the Brazilian legislation mainly for red table wines. From 1986, the total dry extract was measured by indirect method, and the legislation was modifica by increasing the parameters of the ratio between weight alcohol and reduced dry extract. This allowed that the majority of wines were in agreement with the legislation. This work had the objective to compare these two

  5. Diversity of Genetic Resources and Genetic Association Analyses of Green and Dry Chillies of Eastern India Diversidad de Recursos Genéticos y Análisis de Asociación Genética de Ajíes Verdes y Secos del Este de India

    Directory of Open Access Journals (Sweden)

    Arup Chattopadhyay

    2011-09-01

    Full Text Available Chilli (Capsicum annuum L. is regarded as one of the main commercial vegetable and spice crops at the global level. Maximum diversity can be noted among the cultivars/landraces available in India with respect to shape, size, yield, quality, and other traits. The present experiment was conducted to identify the most promising chilli variety suited for green and dry purposes, to study the genetic variability for different traits and to assess the association of different yield attributing traits with the green and dry yield of chilli. Thirty four genotypes were characterized during a 2-yr period. Most of the genotypes possessed the character constellation of C. annuum. Two genotypes, ‘Chaitali Pointed’ and ‘BC CH Sel-4’ were found most promising with respect to green fruit yield (272.79 g, 221.10 g per plant and dry fruit yield (54.56 g, 44.44 g per plant. Phenotypic and Genotypic Coefficient of Variation values for green fruit weight (119.95%, 111.26%, green fruit girth (89.76%, 48.93%, weight of red ripe fruit (112.02%, 111.93%, weight of dry fruit (111.63%, 110.97% and number of fruits per plant (86.05%, 85.02% were recorded to be high. Green fruit yield per plant, ascorbic acid content, and number of fruits per plant also showed very high broad-sense heritability and genetic advance. From the study of correlation and path coefficient analyses, the number of fruits per plant, green fruit length for green chilli, weight of dry fruit and the number of fruits per plant for dry chilli were found to the most important selection indices.El ají (Capsicum annuum L. es considerado como uno de los principales cultivos comerciales de vegetales y especias a nivel mundial. La máxima diversidad puede ser observada entre los cultivares y razas disponibles en India con respecto a forma, tamaño, producción, calidad, y otros rasgos. Este experimento se realizó para identificar la variedad de ají más promisoria y apropiada para fruto verde y seco

  6. Modelación de la transferencia de calor y masa en el absorbedor de una máquina de refrigeración por absorción. // Heat and mass transference modeling in the absorvetor of an absorption cooling device.

    Directory of Open Access Journals (Sweden)

    C. Cisneros Ramírez

    2003-01-01

    Full Text Available En este artículo se dan las expresiones que caracterizan el comportamiento de la temperatura y del producto coeficienteglobal de traspaso de calor (U por el área de traspaso de calor (A , de un absorbedor de una máquina de refrigeración porabsorción que trabaja con la solución amoniaco – agua.Palabras claves: Modelación, absorbedores, refrigeración por absorción.______________________________________________________________________________Abstract.In this article the expressions that characterize the temperature performance and the global heat exchange (U by the heatexchange area (A of the absorvetor of an absorption refrigerating equipment with aqua–ammonia solution are given.Key words: Model, absorber, absorption refrigeration.

  7. Rendimiento y valor nutritivo de forraje de alfalfa (Medicago sativa L. con diferentes dosis de estiércol bovino

    Directory of Open Access Journals (Sweden)

    Cirilo Vázquez-Vázquez

    2010-01-01

    Full Text Available El presente trabajo se realizó en la Comarca Lagunera, estado de Coahuila, México. El objetivo fue evaluar la producción y el valor nutritivo del forraje de tres variedades de alfalfa tratamientos de fertilizado con estiércol de bovino y con riego por goteo subsuperficial. Se determinó la composición del N, P, K, Ca y Mg en el tejido vegetal como un indicador de los volúmenes de extracción para cada nutrimento. Las variedades fueron: CUF 101, Sandor y Altaverde. Se aplicaron cinco tratamientos de estiércol (0, 40, 80, 120, 160 t ha-1 y uno de fertilizante químico (30-100 kg ha-1 de N y P como testigo. Respecto al forraje seco se presentaron diferencias significativas entre los tratamientos de estiércol pero no para variedades. Los valores de producción más altos se observaron en los cortes marzo, abril y junio en los tratamientos de estiércol de 80, 120 y 160 t ha-1 con valores superiores de 4 t ha-1 de forraje seco. En las variables de valor nutritivo del forraje (proteína cruda, fibra acido detergente, fibra neutro detergente y energía, tampoco se detectaron diferencias significativas entre variedades ni entre tratamientos de fertilización. Con respecto a la extracción de N, P, K, Ca y Mg por las plantas, en los cortes 5º al 8º es donde se presentó la mayor extracción de dichos elementos con aproximadamente 160 kg ha-1 de nitrógeno, 12-14 kg ha-1 de fósforo y 125 kg ha-1 de potasio.

  8. Obesity, abdominal obesity, physical activity, and caloric intake in US adults: 1988 to 2010.

    Science.gov (United States)

    Ladabaum, Uri; Mannalithara, Ajitha; Myer, Parvathi A; Singh, Gurkirpal

    2014-08-01

    Obesity and abdominal obesity are associated independently with morbidity and mortality. Physical activity attenuates these risks. We examined trends in obesity, abdominal obesity, physical activity, and caloric intake in US adults from 1988 to 2010. Univariate and multivariate analyses were performed using National Health and Nutrition Examination Survey data. Average body mass index (BMI) increased by 0.37% (95% confidence interval [CI], 0.30-0.44) per year in both women and men. Average waist circumference increased by 0.37% (95% CI, 0.30-0.43) and 0.27% (95% CI, 0.22-0.32) per year in women and men, respectively. The prevalence of obesity and abdominal obesity increased substantially, as did the prevalence of abdominal obesity among overweight adults. Younger women experienced the greatest increases. The proportion of adults who reported no leisure-time physical activity increased from 19.1% (95% CI, 17.3-21.0) to 51.7% (95% CI, 48.9-54.5) in women, and from 11.4% (95% CI, 10.0-12.8) to 43.5% (95% CI, 40.7-46.3) in men. Average daily caloric intake did not change significantly. BMI and waist circumference trends were associated with physical activity level but not caloric intake. The associated changes in adjusted BMIs were 8.3% (95% CI, 6.9-9.6) higher among women and 1.7% (95% CI, 0.68-2.8) higher among men with no leisure-time physical activity compared with those with an ideal level of leisure-time physical activity. Our analyses highlight important dimensions of the public health problem of obesity, including trends in younger women and in abdominal obesity, and lend support to the emphasis placed on physical activity by the Institute of Medicine. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Nutrients, not caloric restriction, extend lifespan in Queensland fruit flies (Bactrocera tryoni).

    Science.gov (United States)

    Fanson, Benjamin G; Weldon, Christopher W; Pérez-Staples, Diana; Simpson, Stephen J; Taylor, Phillip W

    2009-09-01

    Caloric restriction (CR) has been widely accepted as a mechanism explaining increased lifespan (LS) in organisms subjected to dietary restriction (DR), but recent studies investigating the role of nutrients have challenged the role of CR in extending longevity. Fuelling this debate is the difficulty in experimentally disentangling CR and nutrient effects due to compensatory feeding (CF) behaviour. We quantified CF by measuring the volume of solution imbibed and determined how calories and nutrients influenced LS and fecundity in unmated females of the Queensland fruit fly, Bactocera tryoni (Diptera: Tephritidae). We restricted flies to one of 28 diets varying in carbohydrate:protein (C:P) ratios and concentrations. On imbalanced diets, flies overcame dietary dilutions, consuming similar caloric intakes for most dilutions. The response surface for LS revealed that increasing C:P ratio while keeping calories constant extended LS, with the maximum LS along C:P ratio of 21:1. In general, LS was reduced as caloric intake decreased. Lifetime egg production was maximized at a C:P ratio of 3:1. When given a choice of separate sucrose and yeast solutions, each at one of five concentrations (yielding 25 choice treatments), flies regulated their nutrient intake to match C:P ratio of 3:1. Our results (i) demonstrate that CF can overcome dietary dilutions; (ii) reveal difficulties with methods presenting fixed amounts of liquid diet; (iii) illustrate the need to measure intake to account for CF in DR studies and (iv) highlight nutrients rather than CR as a dominant influence on LS.

  10. Effect of solid-meal caloric content on gastric emptying kinetics of solids and liquids.

    Science.gov (United States)

    Urbain, J L; Siegel, J A; Mortelmans, L; van Cutsem, E; van den Maegdenbergh, V; de Roo, M

    1989-08-01

    In this study, we have evaluated the effect of the caloric content of a physiological test meal on the gastric emptying kinetics of solids and liquids. 22 healthy male volunteers were studied in two groups matched for age. After an overnight fast, each volunteer underwent the same test procedure; in the first group (G I), 10 volunteers received a meal consisting of bread, 111In-DTPA water and 1 scrambled egg labeled with 99mTc-labelled sulphur colloid; in the second group (G II) 12 volunteers were given the same meal but with 2 labeled eggs in order to increase the caloric content of the solid phase meal. Simultaneous anterior and posterior images were recorded using a dual-headed gamma camera. Solid and liquid geometric mean data were analyzed to determine the lag phase, the emptying rate and the half-emptying time for both solids and liquids. Solid and liquid gastric half-emptying times were significantly prolonged in G II compared to G I volunteers. For the solid phased, the delay was accounted for by a longer lag phase and a decrease in the equilibrium emptying rate. The emptying rate of the liquid phase was significantly decreased in G II compared to G I. Within each group, no statistically significant difference was observed between solid and liquid emptying rates. We conclude that the caloric content of the solid portion of a meal not only alters the emptying of the solid phase but also affects the emptying of the liquid component of the meal.

  11. [Caloric value and ash content of dominant plants in plantation communities in Heshan of Guangdong, China].

    Science.gov (United States)

    Zeng, Xiao-ping; Cai, Xi-an; Zhao, Ping; Rao, Xing-quan

    2009-03-01

    Different parts of twenty dominant plant species in five plantation communities on the subtropical hilly lands in Heshan of Gunagdong as well as the litters from three of the five plantation communities were sampled, and their gross caloric value (GCV) and ash content were measured by using a PARR-1281 oxygen bomb calorimeter and a muffle furnace. Based on the measurements, the ash-free caloric value (AFCV) of the samples was calculated, and the characteristics of caloric value and ash content of the samples, according to plant part, individual, and plant growth form, were analyzed. The results showed that the GCV and AFCV of leaf, branch, stem wood, stem bark, and root were in the range of 10.7-22.17 kJ x g(-1) and 13.89-23.04 kJ x g(-1), respectively. The GCV and AFCV of leaf were significantly higher than those of other parts (P shrub layer (19.46 kJ x g(-1) > herb layer (18.77 kJ x g(-1)), with indigenous coniferous tree (19.86 kJ x g(-1)) > indigenous broad-leaved tree (19.55 kJ x g(-1)) > exotic eucalyptus (19.18 kJ x g(-1)), while the mean ash content was just the opposite. In Acacia mangium, coniferous, and Schima plantation communities, the GCV and AFCV of litters were higher than those of various plant parts (P mangium and coniferous plantations had higher mean GCV and AFCV than the litters and fresh leaves of tree layer, while the fresh leaves of tree layer in Schima plantation showed higher mean GCV and AFCV.

  12. Lost in processing? Perceived healthfulness, taste and caloric content of whole and processed organic food.

    Science.gov (United States)

    Prada, Marília; Garrido, Margarida V; Rodrigues, David

    2017-07-01

    The "organic" claim explicitly informs consumers about the food production method. Yet, based on this claim, people often infer unrelated food attributes. The current research examined whether the perceived advantage of organic over conventional food generalizes across different organic food types. Compared to whole organic foods, processed organic foods are less available, familiar and prototypical of the organic food category. In two studies (combined N = 258) we investigated how both organic foods types were perceived in healthfulness, taste and caloric content when compared to their conventional alternatives. Participants evaluated images of both whole (e.g., lettuce) and processed organic food exemplars (e.g., pizza), and reported general evaluations of these food types. The association of these evaluations with individual difference variables - self-reported knowledge and consumption of organic food, and environmental concerns - was also examined. Results showed that organically produced whole foods were perceived as more healthful, tastier and less caloric than those produced conventionally, thus replicating the well-established halo effect of the organic claim in food evaluation. The organic advantage was more pronounced among individuals who reported being more knowledgeable about organic food, consumed it more frequently, and were more environmentally concerned. The advantage of the organic claim for processed foods was less clear. Overall, processed organic (vs. conventional) foods were perceived as tastier, more healthful (Study 1) or equally healthful (Study 2), but also as more caloric. We argue that the features of processed food may modulate the impact of the organic claim, and outline possible research directions to test this assumption. Uncovering the specific conditions in which food claims bias consumer's perceptions and behavior may have important implications for marketing, health and public-policy related fields. Copyright © 2017 Elsevier

  13. Olas de calor e influencia urbana en Madrid y su área metropolitana

    Directory of Open Access Journals (Sweden)

    Fernández García, F.

    2008-12-01

    Full Text Available The frequency and duration of the warmest temperature episodes, a common phenomenon under the continental Mediterranean conditions of the Spanish Southern Meseta, has increased in the Madrid area since the 80´s, although their magnitude remains unchanged. The effect of the urban environment on those extreme events has exacerbated the heat load due to the persistence of the high temperatures along the night time hours. Nevertheless, the diversity of the urban morphology introduces a spatial variability on the strength of this nocturnal heat load, aggravating it in the densely urbanized areas and mitigating it in the vicinities of the green areas.

    La frecuencia y duración de los episodios cálidos extremos, un fenómeno habitual en el clima mediterráneo continental de la Meseta Meridional, ha aumentado en el área de Madrid desde los años noventa, aunque su magnitud permanece constante. En el interior de la aglomeración urbana, el efecto general de la ciudad sobre estos eventos climáticos extremos ha supuesto una exacerbación del calor, no tanto por un aumento de la temperatura máxima, como por una persistencia del calor en las horas nocturnas. No obstante, la diversidad de la morfología urbana introduce variaciones espaciales en la intensidad de este calor nocturno, agravando sus efectos en las áreas densamente urbanizadas y mitigándolos en las proximidades de las áreas verdes.

  14. Producto fermentado sin lactosa a partior de batido de frutos secos sin legumbres y/o horchata

    OpenAIRE

    Pérez Martínez, Gaspar; Miralles, María del Carmen; Martí Vidagany, Adolfo; Martínez Ortiz, Isabel

    2004-01-01

    [ES] La invención relaciona a los productos que son fermentado con las bacterias lácticas probiotic de la leche o de una agitación comprendiendo las almendras (Prunus Amygdalus, variedad. los dulcis), las distintas frutas secadas non-vegetable o el orgeat obtuvieron de los tubérculos de la chufa (Cyperus esculentus). Los productos de la invención suministran los beneficios nutritivos de las frutas secadas, el orgeat y las bacterias probiotic añadidas, con un único sabor y una consistencia, un...

  15. Roles of Caloric Restriction, Ketogenic Diet and Intermittent Fasting during Initiation, Progression and Metastasis of Cancer in Animal Models: A Systematic Review and Meta-Analysis: e115147

    National Research Council Canada - National Science Library

    Mengmeng Lv; Xingya Zhu; Hao Wang; Feng Wang; Wenxian Guan

    2014-01-01

      Background The role of dietary restriction regimens such as caloric restriction, ketogenic diet and intermittent fasting in development of cancers has been detected via abundant preclinical experiments...

  16. The late-luteal leptin level, caloric intake and eating behaviors among women with premenstrual dysphoric disorder.

    Science.gov (United States)

    Ko, Chih-Hung; Yen, Cheng-Fang; Long, Cheng-Yu; Kuo, Yu-Ting; Chen, Cheng-Sheng; Yen, Ju-Yu

    2015-06-01

    A marked increased in food intake in the late-luteal phase is a characteristic symptom of premenstrual dysphoric disorder (PMDD). The aim of the study was to evaluate the leptin level, caloric intake, and eating behaviors of women with PMDD across the menstrual cycle among normal-weight and overweight subjects, respectively. A total of 62 women with PMDD and 69 controls were recruited following psychiatric interviewing and underwent prospective investigation. The leptin level, caloric intake, and three factors related to eating behavior were assessed in both the late-luteal and follicular phases. The women with PMDD had greater increases in caloric intake, sweet caloric intake, and uncontrolled eating in the late-luteal phase than the controls. Among the normal-weight women, the leptin level was negatively correlated with caloric intake. The normal-weight women with PMDD had a lower leptin level, a lower leptin/body fat percentage (BFP), a higher caloric intake, and higher uncontrolled eating and emotional eating in the late-luteal phase than the normal-weight controls. Their leptin level was correlated negatively with sweet caloric intake. On the other hand, the overweight women with PMDD had a higher leptin level than the normal-weight women with PMDD and no decline was observed in their leptin level in the late-luteal phase. There were no differences in the leptin level between the overweight women with PMDD and the overweight controls. They also had a higher sweet caloric intake and higher uncontrolled eating and emotional eating than the overweight controls. A decline in the leptin level is associated with late-luteal overeating among normal-weight women with PMDD. Hyperleptinemia and a high sweet caloric intake of overweight women with PMDD should be monitored and addressed in order to attenuate the risk of leptin resistance. The detailed roles of leptin and other psycho-neuro-endocrinology factors in the mechanism of overeating among women with PMDD should

  17. Evaluation of a direct contact heat exchanger; Evaluacion de un intercambiador de calor de contacto directo

    Energy Technology Data Exchange (ETDEWEB)

    Siqueiros, J.; Bonilla, O. [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1997-12-31

    In this paper the application areas of the direct contact heat exchangers is discussed, as well as its main characteristics. A description is made of the experimental equipment designed and built at pilot scale including the instrumentation employed. The methodology employed as well as the analysis and the discussion of the results are also presented. [Espanol] Se mencionan las areas de aplicacion de los intercambiadores de calor de contacto directo, asi como sus caracteristicas principales. Se describe el equipo experimental a nivel piloto disenado y construido incluyendo la instrumentacion utilizada. Se presenta la metodologia empleada asi como el analisis y discusion de los resultados.

  18. Identificación de incrustaciones en ciclones recuperadores de calor de hornos DOPOL

    Directory of Open Access Journals (Sweden)

    Triviño Vázquez, Fernando

    1979-12-01

    Full Text Available Not avaible

    En un ciclón recuperador de calor, situado a la entrada del horno de clinquerización tipo DOPOL, se producían unas incrustaciones sedimentarias que terminaban produciendo la obstrucción del ciclón. Simultáneamente aparecían dificultades de marcha durante el crecimiento, por sedimentación- fusión, de dichas incrustaciones. Finalmente era necesaria la parada del horno para la limpieza del ciclón.

  19. The minimal caloric test asymmetric response in vertigo-free migraine patients

    Directory of Open Access Journals (Sweden)

    Eliana Teixeira Maranhão

    2016-02-01

    Full Text Available ABSTRACT Vertigo symptoms and subclinical vestibular dysfunctions may occur in migraine. The Minimal Caloric Test (MCT, an easy-to-perform, convenient and yet informative procedure was used to test the vestibular function in 30 vertigo-free migraine patients outside attacks and 30 paired controls. Although not statistically significant, a right-to-left nystagmus duration asymmetry greater than 25% was present in both groups. This difference was greater in the patients group, suggesting the presence of subclinical vestibular imbalance in migraine.

  20. Targeting energy metabolism in brain cancer with calorically restricted ketogenic diets.

    Science.gov (United States)

    Seyfried, Thomas N; Kiebish, Michael; Mukherjee, Purna; Marsh, Jeremy

    2008-11-01

    Information is presented on the calorically restricted ketogenic diet (CRKD) as an alternative therapy for brain cancer. In contrast to normal neurons and glia, which evolved to metabolize ketone bodies as an alternative fuel to glucose under energy-restricted conditions, brain tumor cells are largely glycolytic due to mitochondrial defects and have a reduced ability to metabolize ketone bodies. The CRKD is effective in managing brain tumor growth in animal models and in patients, and appears to act through antiangiogenic, anti-inflammatory, and proapoptotic mechanisms.

  1. Mechanism-Based Modeling of Gastric Emptying Rate and Gallbladder Emptying in Response to Caloric Intake

    DEFF Research Database (Denmark)

    Guiastrennec, B; Sonne, David Peick; Hansen, M

    2016-01-01

    concentrations, and GBE was developed on data from 33 patients with type 2 diabetes and 33 matched nondiabetic individuals who were administered various test drinks. A feedback action of the caloric content entering the proximal small intestine was identified for the rate of GE. The cholecystokinin...... concentrations were not predictive of GBE, and an alternative model linking the nutrients amount in the upper intestine to GBE was preferred. Relative to fats, the potency on GBE was 68% for proteins and 2.3% for carbohydrates. The model predictions were robust across a broad range of nutritional content and may...

  2. Relationship of Mediterranean diet and caloric intake to phenoconversion in Huntington disease.

    Science.gov (United States)

    Marder, Karen; Gu, Yian; Eberly, Shirley; Tanner, Caroline M; Scarmeas, Nikolaos; Oakes, David; Shoulson, Ira

    2013-11-01

    Adherence to Mediterranean-type diet (MeDi) may delay onset of Alzheimer and Parkinson diseases. Whether adherence to MeDi affects time to phenoconversion in Huntington disease (HD), a highly penetrant, single-gene disorder, is unknown. To determine if MeDi modifies the time to clinical onset of HD (phenoconversion) in premanifest carriers participating in Prospective Huntington at Risk Observational Study (PHAROS), and to examine the effects of body mass index and caloric intake on time to phenoconversion. A prospective cohort study of 41 Huntington study group sites in the United States and Canada involving 1001 participants enrolled in PHAROS between July 1999 and January 2004 who were followed up every 9 months until 2010. A total of 211 participants aged 26 to 57 years had an expanded CAG repeat length (≥ 37). A semiquantitative food frequency questionnaire was administered 33 months after baseline. We calculated daily gram intake for dairy, meat, fruit, vegetables, legumes, cereals, fish, monounsaturated and saturated fatty acids, and alcohol and constructed MeDi scores (0-9); higher scores indicate higher adherence. Demographics, medical history, body mass index, and Unified Huntington's Disease Rating Scale (UHDRS) score were collected. Cox proportional hazards regression models to determine the association of MeDi and phenoconversion. RESULTS Age, sex, caloric intake, education status, and UHDRS motor scores did not differ among MeDi tertiles (0-3, 4-5, and 6-9). The highest body mass index was associated with the lowest adherence to MeDi. Thirty-one participants phenoconverted. In a model adjusted for age, CAG repeat length, and caloric intake, MeDi was not associated with phenoconversion (P for trend = 0.14 for tertile of MeDi, and P = .22 for continuous MeDi). When individual components of MeDi were analyzed, higher dairy consumption (hazard ratio, 2.36; 95% CI, 1.0-5.57; P = .05) and higher caloric intake (P = .04) were associated with risk of

  3. Efectos no-newtonianos en un cambiador de calor comercial de doble tubo para aplicaciones alimentarias

    OpenAIRE

    Molina Sánchez, Alberto Aurelio

    2006-01-01

    El objetivo del presente proyecto es evaluar la importancia que los efectos no newtonianos de los productos alimentarios ejercen sobre el flujo y la transferencia de calor en procesos industriales. En concreto, el estudio se basa en el comportamiento reológico seudoplástico mostrado por el cremogenado de melocotón durante un proceso de enfriamiento. El proyecto consta de una primera parte de recopilación bibliográfica en la que se exponen los conocimientos necesarios para poder llevar a cabo ...

  4. Tecnologías emergentes para la conservación de alimentos sin calor

    OpenAIRE

    Fernández Molina, Juan José; Barbosa-Cánovas, Gustavo V.; Swanson, Barry G.

    2001-01-01

    Not available

    Se han investigado los principios básicos de tres tecnologías emergentes para pasteurizar y esterilizar alimentos sin empleo del calor Mediante numerosos estudios se ha comprobado la efectividad de los campos eléctricos pulsantes de alta intensidad (CEPAI), los pulsos de luz (PL) y los campos magnéticos oscilantes (CMO) en la destrucción de microorganismos y enzimas de sistemas alimentarios. En la inactivación microbiana por CEPA!, el blanco principal es la me...

  5. Caloric stimulation

    Science.gov (United States)

    ... hearing and balance. The test also checks for damage to the brain stem. ... eye movements do not occur even after ice cold water is given, there may be damage to the: Nerve of the inner ear Balance ...

  6. Fracionamento a seco da gordura de frango em escala piloto Dry fractionation of chicken fat in pilot scale

    Directory of Open Access Journals (Sweden)

    Ming Chih Chiu

    2007-09-01

    Full Text Available O consumo mundial de carne de frango foi de 57,8 milhões de toneladas em 2006, segundo estimativas do United States Department of Agriculture (USDA. A gordura abdominal de frango corresponde a aproximadamente 2 a 2,5% do peso da carcaça. Os objetivos deste trabalho foram fracionar esta gordura e caracterizar as frações obtidas através da análise térmica e das propriedades físico-químicas. A gordura de frango foi submetida ao fracionamento a seco para obter uma fração sólida à temperatura ambiente. As etapas de cristalização e filtração foram realizadas utilizando procedimentos industriais em escala piloto. As amostras foram avaliadas quanto aos pontos de amolecimento e de fusão, consistência, conteúdo de gordura sólida, composição em ácidos graxos e em triacilgliceróis, índices de iodo e saponificação, e comportamento térmico. Os resultados demonstraram que a gordura de frango é composta por 68,7% de ácidos graxos insaturados. Entre os ácidos graxos insaturados, os monoinsaturados, como o ácido oléico, são considerados desejáveis com relação à redução do risco de enfermidades cardiovasculares. O elevado ponto de fusão das estearinas em relação à gordura de frango foi devido aos maiores teores de ácidos graxos saturados nestas frações, principalmente os ácidos palmítico e esteárico. A gordura de frango e a oleína à temperatura de 10 ºC apresentaram-se plásticas e espalháveis. O alto rendimento das oleínas sugere a possibilidade de aplicação destas frações como óleo para frituras e na síntese de lipídios estruturados. As estearinas podem ser utilizadas como componentes na fabricação de gorduras para aplicação em margarinas para pastelaria, massas folhadas e gorduras para bolos e sorvetes.The world consume of chicken meat was 57.8 million tons in 2006, according to the United States Department of Agriculture (USDA estimative. The abdominal chicken fat corresponds to approximately 2

  7. Efecto de la Composición Química del Metal de Aporte y del Calor Aportado Sobre la Microestructura y las Propiedades Mecánicas de Juntas Soldadas de Aceros Inoxidables Dúplex

    Directory of Open Access Journals (Sweden)

    Sebastián Zappa

    Full Text Available Resumen Los aceros inoxidables dúplex poseen una microestructura dual (ferrita y austenita con contenidos aproximadamente iguales y se caracterizan por tener buena soldabilidad, buenas propiedades mecánicas y una alta resistencia a la corrosión generalizada y localizada. Gracias a estas características, estos aceros son los principales materiales a emplear en cañerías con altas exigencias, ampliamente utilizados en varias industrias, principalmente la petroquímica. Dichas propiedades están controladas por la composición química, el equilibrio microestructural y la ausencia de compuestos intermetálicos. El objetivo de este trabajo fue estudiar la influencia de la composición química del metal de aporte y el calor aportado sobre la microestructura y las propiedades mecánicas en juntas soldadas de cañerías de acero inoxidable dúplex. El metal base utilizado fue un acero inoxidable dúplex UNS S31803 de 8” de diámetro y 8,18 mm de espesor y los metales de aporte fueron dos alambres tubulares que depositan aceros inoxidables dúplex y lean dúplex (AWS A5.22: E2209T1-1 y E2209T1-G, mediante el proceso de soldadura semi-automático bajo protección gaseosa, soldados con alto y bajo calor aportado. De cada probeta se extrajeron muestras donde se determinó la composición química, se realizó la caracterización microestructural y se determinaron las propiedades mecánicas (dureza, tracción y Charpy-V.

  8. USO DE BLOQUES NUTRICIONALES COMO COMPLEMENTO PARA OVINOS EN EL TROPICO SECO DEL ALTIPLANO CENTRAL DE MEXICO

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    Paulina Vazquez-Mendoza

    2012-01-01

    Full Text Available El objetivo del estudio fue evaluar el comportamiento productivo de ovinos complementados con bloques nutricionales en confinamiento y pastoreo. Se llevaron a cabo dos experimentos, el Experimento 1 se realizó con ovinos en confinamiento, el Experimento 2 se realizó con ovinos en pastoreo continuo en pastizales nativos. Para ambos experimentos 1 y 2 se utilizaron quince ovinos F1 (Dorper x Pelibuey, con un peso inicial de 17±3 y 26 ± 3 kg respectivamente. Los tratamientos en el experimento 1 fueron: T1= dieta basal + BN1 (conteniendo L. Leucocephala T2= dieta basal + BN2 (conteniendo salvado de trigo y T3= Dieta basal (Testigo. Los tratamientos en el Experimento 2 fueron: T1= Pastoreo + BN1, T2= Pastoreo + BN2 y T3= Pastoreo (control. Las variables respuestas en ambos experimentos fueron: ganancia diaria de peso (GDP, consumo de bloque nutricional (CBN, consumo de dieta basal (CDB consumo total (CT, digestibilidad aparente de la materia seca de bloques nutricionales (DAMSBN, digestibilidad aparente de la materia seca de la dieta basal (DAMSDB. En ambos experimentos los datos se analizaron mediante un diseño completamente al azar. En el Experimento 1 se encontraron diferencias en la GDP (P

  9. Cálculo de la resistencia a la fatiga superficial en superficies con lubricación elastohidrodinámica mediante el criterio de Dang Van

    OpenAIRE

    Guerra Ochoa, Eduardo de la; Chacón Tanarro, Enrique; Lafont Morgado, Pilar; Echávarri Otero, Javier; Muñoz Guijosa, Juan Manuel; Muñoz Sanz, José Luis; Diaz Lantada, Andres

    2010-01-01

    Los fenómenos de fatiga superficial en sus diferentes escalas (micropitting, pitting, spalling), aparecen en multitud de elementos mecánicos en contacto lubricado como pueden ser los engranajes o rodamientos o en elementos con contacto seco como son las ruedas de ferrocarril. Los defectos que aparecen en las superficies en contacto debidos a estos fenómenos empeoran las condiciones de funcionamiento, provocando vibraciones, desgaste prematuro y en los casos más extremos el fallo de la máq...

  10. Uso de transdutores de fluxo de calor no estudo da transferência de calor em alimentos embalados The use of heat flux transducers to study heat transfer in canned foods

    OpenAIRE

    Carciofi, B.; S. Güths; J. B. Laurindo

    2002-01-01

    A densidade de fluxo de calor que atravessa uma superfície é classicamente determinada mediante a medição das temperaturas apropriadas e da aplicação da Lei de Fourier. Uma alternativa a esse procedimento é a utilização de transdutores de fluxo de calor, os quais geram um sinal elétrico proporcional ao fluxo térmico que os atravessa. Neste trabalho, processos de aquecimento e de resfriamento de alimentos foram estudados em laboratório, utilizando-se um recipiente de vidro cilíndrico para simu...

  11. Factores de riesgo ambientales y componentes del síndrome metabólico en adolescentes con exceso de peso

    Directory of Open Access Journals (Sweden)

    Nora Elena Múnera

    2012-03-01

    Conclusiones. Los factores de riesgo ambientales asociados con los componentes del síndrome metabólico en este estudio fueron el mayor consumo de calorías, carbohidratos complejos y simples, todos relacionados directamente con el IMC; por el contrario, el nivel de actividad física, los antecedentes familiares y los personales no mostraron ninguna asociación. El síndrome metabólico sólo se presentó en jóvenes con obesidad.   DOI: http://dx.doi.org/10.7705/biomedica.v32i1.595

  12. Computing simulated endolymphatic flow thermodynamics during the caloric test using normal and hydropic duct models.

    Science.gov (United States)

    Rey-Martinez, Jorge; McGarvie, Leigh; Pérez-Fernández, Nicolás

    2017-03-01

    The obtained simulations support the underlying hypothesis that the hydrostatic caloric drive is dissipated by local convective flow in a hydropic duct. To develop a computerized model to simulate and predict the internal fluid thermodynamic behavior within both normal and hydropic horizontal ducts. This study used a computational fluid dynamics software to simulate the effects of cooling and warming of two geometrical models representing normal and hydropic ducts of one semicircular horizontal canal during 120 s. Temperature maps, vorticity, and velocity fields were successfully obtained to characterize the endolymphatic flow during the caloric test in the developed models. In the normal semicircular canal, a well-defined endolymphatic linear flow was obtained, this flow has an opposite direction depending only on the cooling or warming condition of the simulation. For the hydropic model a non-effective endolymphatic flow was predicted; in this model the velocity and vorticity fields show a non-linear flow, with some vortices formed inside the hydropic duct.

  13. Remission of anosognosia for right hemiplegia and neglect after caloric vestibular stimulation.

    Science.gov (United States)

    Ronchi, Roberta; Rode, Gilles; Cotton, François; Farnè, Alessandro; Rossetti, Yves; Jacquin-Courtois, Sophie

    2013-01-01

    Neglect and related phenomena, as anosognosia for hemiplegia and somatoparaphrenia, are often associated to right-hemisphere lesions. These deficits can be alleviated by caloric vestibular stimulation, but little is known about the efficacy of this physiological intervention on neglect following left-hemisphere lesions. Here we report the case of an ambidextrous left brain-damaged patient with severe right personal and extrapersonal neglect, anosognosia for right hemiplegia and somatoparaphrenia. These symptoms co-occurred with more typical manifestations of left-brain damage, such as aphasia and apraxia. Neurological examination revealed right hemiplegia, hemianesthesia and hemianopia. Visuo-spatial tests for personal and extrapersonal neglect, as well as an anosognosia questionnaire, were submitted before and after caloric vestibular stimulation. Results showed a dramatic improvement of anosognosia for hemiplegia and neglect; no change was observed for the remaining deficits. The results confirm the notion of the selectivity of vestibular stimulation for neglect and related disorders and extend this notion by showing that similar effects can be obtained after lesion of the left hemisphere, suggesting that similar mechanisms are responsible for left- and right-sided neglect. Such a peculiar association of language and visuo-spatial disorders jointly present after a left-sided lesion opens the question of the link between handedness and lateralization of cognitive functions.

  14. Modeling body mass variation: incorporating social influence into calculations of caloric intake and energy expenditure.

    Science.gov (United States)

    Hernández-Hernández, Ana María; Huerta-Quintanilla, Rodrigo

    2014-01-01

    Variations in individual body mass and composition have long been a key focus in the health sciences, particularly now that overweight and obesity are considered as public health problems. We study a mathematical model that describes body mass variations which are determined by the energy balance between caloric intake and total energy expenditure. To calculate the change in caloric intake and energy expenditure over time, we proposed a relationship for each of these quantities, and we used measured values that are reported in the literature for the initial conditions. To account for small variations in the daily energy balance of an individual, we include social interactions as the multiplication of two terms: social proximity and social influence. We observe that social interactions have a considerable effect when the body mass of an individual is quite constant and social interactions take random values. However, when an individual's mass value changes (either increases or decreases), social interactions do not have a notable effect. In our simulation, we tested two different models that describe the body mass composition, and it resulted that one fits better the data.

  15. Caloric vestibular stimulation as a treatment for conversion disorder: A case report and medical hypothesis

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    Michael eNoll-Hussong

    2014-06-01

    Full Text Available Conversion disorder is a medical condition in which a person has paralysis, blindness, or other neurological symptoms that cannot be clearly explained physiologically. To date, there is neither specific nor conclusive treatment. In this paper, we draw together a number of disparate pieces of knowledge to propose a novel intervention to provide transient alleviation for this condition. As caloric vestibular stimulation (CVS has been demonstrated to modulate transiently a variety of cognitive functions associated with brain activations, especially in the temporal-parietal cortex, anterior cingulate cortex, and insular cortex, there is evidence to assume an effect in specific mental disorders. Therefore, we go on to hypothesize that lateralized cold vestibular caloric stimulation will be effective in treating conversion disorder and we present provisional evidence from one patient that supports this conclusion. If our hypothesis is correct, this will be the first time in psychiatry and neurology that a clinically well-known mental disorder, long considered difficult to understand and to treat, is relieved by a simple or common, non-invasive medical procedure.

  16. In-shell pistachio nuts reduce caloric intake compared to shelled nuts.

    Science.gov (United States)

    Honselman, Carla S; Painter, James E; Kennedy-Hagan, Karla J; Halvorson, Amber; Rhodes, Kathy; Brooks, Tamatha L; Skwir, Kaitlin

    2011-10-01

    It was hypothesized that consuming in-shell pistachios, compared to shelled pistachios, causes individuals to consume less. A convenience sample of students at a mid-western university (n=140) was recruited, asking them to evaluate a variety of brands of pistachios. A survey at the end of class determined fullness and satisfaction. Subjects entering the classroom were given a 16-ounce cup and asked to self-select a portion of pistachios. Portion weight was recorded and subjects consumed pistachios at their leisure during class. At class end, pistachios remaining in the cup were weighed and total consumption by weight was determined. The caloric content of each portion was then calculated. In condition one, subjects offered in-shell pistachios consumed an average of 125 calories. In condition two, subjects offered shelled pistachios consumed an average of 211 calories; a difference of 86 calories. Subjects in condition one consumed 41% fewer calories compared to subjects in condition two (p≤.01). Fullness and satisfaction ratings were not significantly different (p≥.01). Caloric intake was influenced by the initial form of the food. The difference in calories consumed may be due to the additional time needed to shell the nuts or the extra volume perceived when consuming in-shell nuts. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Is caloric restriction associated with development of eating-disorder symptoms? Results from the CALERIE trial.

    Science.gov (United States)

    Williamson, Donald A; Martin, Corby K; Anton, Stephen D; York-Crowe, Emily; Han, Hongmei; Redman, Leanne; Ravussin, Eric

    2008-01-01

    This study tested a secondary hypothesis of the CALERIE trial (Heilbronn et al., 2006) that a 12-month period of intentional dietary restriction would be associated with an increase in eating disorder symptoms. To test this hypothesis, 48 overweight adults were randomly assigned to four treatment arms in a 12-month study: (1) 25% calorie restriction, (2) 12.5% calorie restriction and 12.5% increased energy expenditure by structured exercise, (3) low-calorie diet, and (4) healthy diet (no-calorie restriction). Primary outcome measures for the study were changes in: eating disorder symptoms, mood, dietary restraint, body weight, and energy balance. All three dietary restriction arms were associated with increased dietary restraint and negative energy balance, but not with increased ED symptoms or other harmful psychological effects. Participants in the three calorie restriction arms lost significant amounts of body weight. The psychological and behavioral effects were maintained during a 6-month follow-up period. These results did not support the hypothesis that caloric restriction causes increased eating disorder symptoms in overweight adults. In general, caloric restriction had either benign or beneficial psychological and behavioral effects. (Copyright) 2008 APA.

  18. AMP activated protein kinase is indispensable for myocardial adaptation to caloric restriction in mice.

    Directory of Open Access Journals (Sweden)

    Kai Chen

    Full Text Available Caloric restriction (CR is a robust dietary intervention known to enhance cardiovascular health. AMP activated protein kinase (AMPK has been suggested to mediate the cardioprotective effects of CR. However, this hypothesis remains to be tested by using definitive loss-of-function animal models. In the present study, we subjected AMPKα2 knockout (KO mice and their wild type (WT littermates to a CR regimen that reduces caloric intake by 20%-40% for 4 weeks. CR decreased body weight, heart weight and serum levels of insulin in both WT and KO mice to the same degree, indicating the effectiveness of the CR protocol. CR activated cardiac AMPK signaling in WT mice, but not in AMPKα2 KO mice. Correspondingly, AMPKα2 KO mice had markedly reduced cardiac function during CR as determined by echocardiography and hemodynamic measurements. The compromised cardiac function was associated with increased markers of oxidative stress, endoplasmic reticulum stress and myocyte apoptosis. Mechanistically, CR down-regulated the expression of ATP5g2, a subunit of mitochondrial ATP synthase, and reduced ATP content in AMPKα2 KO hearts, but not in WT hearts. In addition, CR accelerated cardiac autophagic flux in WT mice, but failed to do so in AMPKα2 KO mice. These results demonstrated that without AMPK, CR triggers adverse effects that can lead to cardiac dysfunction, suggesting that AMPK signaling pathway is indispensible for energy homeostasis and myocardial adaptation to CR, a dietary intervention that normally produces beneficial cardiac effects.

  19. Transferencia de calor en la colada continua de aceros. I parte. El molde

    Directory of Open Access Journals (Sweden)

    Cicutti, C.

    1997-10-01

    Full Text Available The continuous casting mold plays the important role of receiving the liquid steel and allowing an uniform and defect free solidified skin to be developed. In this work, the different heat transfer mechanisms which are present from the liquid steel to the mold cooling water are reviewed. The effect of operating variables on heat extraction and the relationship between global and distributed heat flux are also analyzed.

    El molde de colada continua cumple la importante función de recibir el acero líquido y permitir que se desarrolle una capa solidificada uniforme y libre de defectos. En este trabajo se revisan los distintos mecanismos implicados en el proceso de transferencia de calor, desde el acero líquido hasta el agua de refrigeración del molde. Se analiza también el efecto de las distintas variables de funcionamiento en la extracción calórica producida y la relación entre el flujo global de calor y su distribución a lo largo del molde.

  20. Patrones de distribución de felinos silvestres (Carnívora: Felidae en el trópico seco del Centro-Occidente de México

    Directory of Open Access Journals (Sweden)

    Juan Felipe Charre-Medellín

    2015-09-01

    Full Text Available El estado de Michoacán se caracteriza por presentar una importante heterogeneidad ambiental, en términos de clima, topografía y tipos de vegetación, que incluyen al bosque tropical seco que se encuentra en peligro de extinción a nivel mundial. Algunos trabajos mencionan la presencia de las seis especies de felinos que habitan en México, para la región; sin embargo, la evidencia para apoyar estos trabajos es escasa, por lo que llenar esta falta de información es especialmente crítico en el caso de especies o hábitats amenazados. El objetivo de este estudio fue sistematizar la información y analizar los patrones de distribución de los felinos en el estado de Michoacán, dentro del centro-occidente de México. Realizamos una revisión de la información bibliográfica y contenida en bases de datos sobre la presencia de felinos en esta región. Asimismo, realizamos trabajo de campo que en el curso de diez años donde se aplicaron distintos métodos para detectar la presencia de especies de felinos (recorrido de senderos para obtener evidencia directa e indirecta de la presencia de las especies, trampas cámara y entrevistas. Localizamos 29 registros de presencia en literatura y bases de datos. Por otra parte acumulamos un total de 1 107.5 km de transectos recorridos y 8 699 días/cámara-trampa. A través de este esfuerzo de muestreo, generamos 672 registros de presencia de las seis especies. Lynx rufusfue la especie con menos registros totales (n = 3 y cuya distribución contrastó más con la del resto de las especies. La especie con más registros fue Leopardus pardalis(n = 343. En general, el 89% de los registros de felinos se obtuvieron por debajo de los 1 000 msnm. En promedio, la temperatura media anual y la precipitación anual donde se ubicaron los registros fue de 24 °C y 1 040 mm respectivamente. La especie que mostro un patrón más claro en términos de temperatura y precipitación fue L. rufus(15.8 ± 1.3°C y 941 ± 171

  1. The calorically restricted ketogenic diet, an effective alternative therapy for malignant brain cancer

    Directory of Open Access Journals (Sweden)

    Zhou Weihua

    2007-02-01

    Full Text Available Abstract Background Malignant brain cancer persists as a major disease of morbidity and mortality in adults and is the second leading cause of cancer death in children. Many current therapies for malignant brain tumors fail to provide long-term management because they ineffectively target tumor cells while negatively impacting the health and vitality of normal brain cells. In contrast to brain tumor cells, which lack metabolic flexibility and are largely dependent on glucose for growth and survival, normal brain cells can metabolize both glucose and ketone bodies for energy. This study evaluated the efficacy of KetoCal®, a new nutritionally balanced high fat/low carbohydrate ketogenic diet for children with epilepsy, on the growth and vascularity of a malignant mouse astrocytoma (CT-2A and a human malignant glioma (U87-MG. Methods Adult mice were implanted orthotopically with the malignant brain tumors and KetoCal® was administered to the mice in either unrestricted amounts or in restricted amounts to reduce total caloric intake according to the manufacturers recommendation for children with refractory epilepsy. The effects KetoCal® on tumor growth, vascularity, and mouse survival were compared with that of an unrestricted high carbohydrate standard diet. Results KetoCal® administered in restricted amounts significantly decreased the intracerebral growth of the CT-2A and U87-MG tumors by about 65% and 35%, respectively, and significantly enhanced health and survival relative to that of the control groups receiving the standard low fat/high carbohydrate diet. The restricted KetoCal® diet reduced plasma glucose levels while elevating plasma ketone body (β-hydroxybutyrate levels. Tumor microvessel density was less in the calorically restricted KetoCal® groups than in the calorically unrestricted control groups. Moreover, gene expression for the mitochondrial enzymes, β-hydroxybutyrate dehydrogenase and succinyl-CoA: 3-ketoacid Co

  2. The calorically restricted ketogenic diet, an effective alternative therapy for malignant brain cancer.

    Science.gov (United States)

    Zhou, Weihua; Mukherjee, Purna; Kiebish, Michael A; Markis, William T; Mantis, John G; Seyfried, Thomas N

    2007-02-21

    Malignant brain cancer persists as a major disease of morbidity and mortality in adults and is the second leading cause of cancer death in children. Many current therapies for malignant brain tumors fail to provide long-term management because they ineffectively target tumor cells while negatively impacting the health and vitality of normal brain cells. In contrast to brain tumor cells, which lack metabolic flexibility and are largely dependent on glucose for growth and survival, normal brain cells can metabolize both glucose and ketone bodies for energy. This study evaluated the efficacy of KetoCal, a new nutritionally balanced high fat/low carbohydrate ketogenic diet for children with epilepsy, on the growth and vascularity of a malignant mouse astrocytoma (CT-2A) and a human malignant glioma (U87-MG). Adult mice were implanted orthotopically with the malignant brain tumors and KetoCal was administered to the mice in either unrestricted amounts or in restricted amounts to reduce total caloric intake according to the manufacturers recommendation for children with refractory epilepsy. The effects KetoCal on tumor growth, vascularity, and mouse survival were compared with that of an unrestricted high carbohydrate standard diet. KetoCal administered in restricted amounts significantly decreased the intracerebral growth of the CT-2A and U87-MG tumors by about 65% and 35%, respectively, and significantly enhanced health and survival relative to that of the control groups receiving the standard low fat/high carbohydrate diet. The restricted KetoCal diet reduced plasma glucose levels while elevating plasma ketone body (beta-hydroxybutyrate) levels. Tumor microvessel density was less in the calorically restricted KetoCal groups than in the calorically unrestricted control groups. Moreover, gene expression for the mitochondrial enzymes, beta-hydroxybutyrate dehydrogenase and succinyl-CoA: 3-ketoacid CoA transferase, was lower in the tumors than in the contralateral normal

  3. General and persistent effects of high-intensity sweeteners on body weight gain and caloric compensation in rats

    Science.gov (United States)

    Swithers, Susan E.; Baker, Chelsea R.; Davidson, T.L.

    2009-01-01

    In four experiments, we assessed the generality of previous findings (Swithers & Davidson, 2008) that increased caloric intake, body weight gain, and reduced caloric compensation are exhibited by rats that consume a diet containing a nonnutritive, high intensity sweetener. In this earlier work, rats consumed a diet in which saccharin was mixed in low-fat yogurt, and animals were provided with a fixed amount of the yogurt. The present experiments showed that the effects of saccharin on energy intake and body weight gain are also obtained when rats were given Acesulfame Potassium (AceK), a nonnutritive high intensity sweetener that is chemically distinct from saccharin. Increased energy intake and body weight gain and impaired caloric compensation were also obtained with a saccharin-sweetened base diet (refried beans) that was calorically similar, but nutritionally distinct from low-fat yogurt. The present studies also extended earlier findings by showing that body weight differences persist after saccharin-sweetened diets are discontinued and following a shift to a diet sweetened with glucose. In addition, rats first exposed to a diet sweetened with glucose still gain additional weight when subsequently exposed to a saccharin sweetened diet. The effect of saccharin on caloric compensation was more complex in that it appeared to depend on the type of diet (yogurt or beans) in which saccharin was consumed prior to testing. The results of these experiments add support to the hypothesis that exposure to weak or non-predictive relationships between sweet tastes and caloric consequences may lead to positive energy balance. PMID:19634935

  4. Overeat today, skip the scale tomorrow: An examination of caloric intake predicting nonadherence to daily self-weighing.

    Science.gov (United States)

    Tanenbaum, Molly L; Ross, Kathryn M; Wing, Rena R

    2016-11-01

    Daily self-weighing is an effective weight loss strategy. Little is known about "micro" factors influencing nonadherence to self-weighing (e.g., daily overeating). It was hypothesized that increased caloric intake on a given day would increase odds of not self-weighing the following day. Daily self-reports of weight and caloric intake were collected from 74 adults with overweight and obesity (mean BMI = 31.2 ± 4.5 kg/m2 , age = 50.6 ± 10 years, 69% female, 87% Caucasian) throughout a 12-week Internet-based weight management intervention. Multilevel logistic regression investigated odds of nonadherence to self-weighing on a given day based on the previous day's caloric intake. Self-monitoring adherence was high (weights: 87%; calories: 85%); adherence was associated with greater 12-week weight loss (weighing: r = -0.24, P = 0.04; calories: r = -0.26, P = 0.04). Increased caloric intake on a given day, relative to the individual's average intake, was associated with increased odds of nonadherence to self-weighing the next day (F(1,5106)  = 12.66, P = 0.0004, β = 0.001). For example, following a day of eating 300 calories more than usual, odds of not self-weighing increased by 1.33. Odds of nonadherence to self-weighing increased following a day with higher-than-usual caloric intake. Weight management interventions collecting daily self-monitoring data could provide support to participants who report increased caloric intake to prevent self-weighing nonadherence. © 2016 The Obesity Society.

  5. Predictive properties of the video head impulse test: measures of caloric symmetry and self-report dizziness handicap.

    Science.gov (United States)

    McCaslin, Devin L; Jacobson, Gary P; Bennett, Marc L; Gruenwald, Jill M; Green, Andrea P

    2014-01-01

    The purpose of this investigation was to determine whether a predictable relationship existed between self-reported dizziness handicap and video Head Impulse Test (vHIT) results in a large sample of patients reporting to a dizziness clinic. Secondary objectives included describing the characteristics of the vHIT ipsilesional and contralesional vestibulo-ocular reflex slow-phase velocity in patients with varying levels of canal paresis. Finally, the authors calculated the sensitivity and specificity of the vHIT for detecting horizontal semicircular canal impairment using the caloric test as the "gold standard." Participants were 115 adults presenting to a tertiary medical care center with symptoms of dizziness. Participants were administered a measure of self-report dizziness handicap (i.e., Dizziness Handicap Inventory) and underwent caloric testing and vHIT at the same appointment. Results showed that (1) there were no significant group differences (i.e., vHIT normal versus vHIT abnormal) in the Dizziness Handicap Inventory total score, (2) both ipsilesional and contralateral velocity gain decreased with increases in caloric paresis, and (3) a caloric asymmetry of 39.5% was determined to be the cutoff that maximized discrimination of vHIT outcome. The level of self-reported dizziness handicap is not predicted by the outcome of the vHIT, which is consistent with the majority of published reports describing the poor relationship between quantitative tests of vestibular function and dizziness handicap. Further, the study findings have demonstrated that vHIT and caloric data are not redundant, and each test provides unique information regarding the functional integrity of the horizontal semicircular canal at different points on the frequency spectrum. The vHIT does offer some advantages over caloric testing, but at the expense of sensitivity. The vHIT can be completed in less time, is not noxious to the patient, and requires very little laboratory space. However, the

  6. Inferior vestibular neuritis: 3 cases with clinical features of acute vestibular neuritis, normal calorics but indications of saccular failure

    Directory of Open Access Journals (Sweden)

    Økstad Siri

    2006-12-01

    Full Text Available Abstract Background Vestibular neuritis (VN is commonly diagnosed by demonstration of unilateral vestibular failure, as unilateral loss of caloric response. As this test reflects the function of the superior part of the vestibular nerve only, cases of pure inferior nerve neuritis will be lost. Case presentations We describe three patients with symptoms suggestive of VN, but normal calorics. All 3 had unilateral loss of vestibular evoked myogenic potential. A slight, asymptomatic position dependent nystagmus, with the pathological ear down, was observed. Conclusion We believe that these patients suffer from pure inferior nerve vestibular neuritis.

  7. Addressing the policy cacophony does not require more evidence: an argument for reframing obesity as caloric overconsumption.

    Science.gov (United States)

    Shelley, Jacob J

    2012-11-30

    Numerous policies have been proposed to address the public health problem of obesity, resulting in a policy cacophony. The noise of so many policy options renders it difficult for policymakers to determine which policies warrant implementation. This has resulted in calls for more and better evidence to support obesity policy. However, it is not clear that evidence is the solution. This paper argues that to address the policy cacophony it is necessary to rethink the problem of obesity, and more specifically, how the problem of obesity is framed. This paper argues that the frame "obesity" be replaced by the frame "caloric overconsumption", concluding that the frame caloric overconsumption can overcome the obesity policy cacophony. Frames are important because they influence public policy. Understood as packages that define issues, frames influence how best to approach a problem. Consequently, debates over public policy are considered battles over framing, with small shifts in how an issue is framed resulting in significant changes to the policy environment. This paper presents a rationale for reframing the problem of obesity as caloric overconsumption. The frame "obesity" contributes to the policy cacophony by including policies aimed at both energy output and energy input. However, research increasingly demonstrates that energy input is the primary cause of obesity, and that increases in energy input are largely attributable to the food environment. By focusing on policies that aim to prevent increases in energy input, the frame caloric overconsumption will reduce the noise of the obesity policy cacophony. While the proposed frame will face some challenges, particularly industry opposition, policies aimed at preventing caloric overconsumption have a clearer focus, and can be more politically palatable if caloric overconsumption is seen as an involuntary risk resulting from the food environment. The paper concludes that policymakers will be able to make better sense

  8. Addressing the policy cacophony does not require more evidence: an argument for reframing obesity as caloric overconsumption

    Directory of Open Access Journals (Sweden)

    Shelley Jacob J

    2012-11-01

    Full Text Available Abstract Background Numerous policies have been proposed to address the public health problem of obesity, resulting in a policy cacophony. The noise of so many policy options renders it difficult for policymakers to determine which policies warrant implementation. This has resulted in calls for more and better evidence to support obesity policy. However, it is not clear that evidence is the solution. This paper argues that to address the policy cacophony it is necessary to rethink the problem of obesity, and more specifically, how the problem of obesity is framed. This paper argues that the frame “obesity” be replaced by the frame “caloric overconsumption”, concluding that the frame caloric overconsumption can overcome the obesity policy cacophony. Discussion Frames are important because they influence public policy. Understood as packages that define issues, frames influence how best to approach a problem. Consequently, debates over public policy are considered battles over framing, with small shifts in how an issue is framed resulting in significant changes to the policy environment. This paper presents a rationale for reframing the problem of obesity as caloric overconsumption. The frame “obesity” contributes to the policy cacophony by including policies aimed at both energy output and energy input. However, research increasingly demonstrates that energy input is the primary cause of obesity, and that increases in energy input are largely attributable to the food environment. By focusing on policies that aim to prevent increases in energy input, the frame caloric overconsumption will reduce the noise of the obesity policy cacophony. While the proposed frame will face some challenges, particularly industry opposition, policies aimed at preventing caloric overconsumption have a clearer focus, and can be more politically palatable if caloric overconsumption is seen as an involuntary risk resulting from the food environment. Summary

  9. Avaliação da atividade anti-séptica de extrato seco de Stryphnodendron adstringens (Mart. Coville e de preparação cosmética contendo este extrato

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    Tatiana M. Souza

    Full Text Available As espécies pertencentes ao gênero Stryphnodendron são conhecidas como "barbatimão" e são nativas do cerrado brasileiro. Possuem taninos como metabólitos secundários primordiais de suas cascas apresentando, entre outras, atividade antimicrobiana e cicatrizante. A concentração bactericida mínima (CBM do extrato seco das cascas de Stryphnodendron adstringens frente a duas bactérias Gram-positivas e uma bactéria Gram-negativa foi determinada pela técnica de diluição em tubos. A atividade antimicrobiana do extrato seco e a atividade anti-séptica de sabonete líquido contendo o extrato seco foram avaliadas pelo método de difusão em ágar. O extrato apresentou valores de concentração bactericida mínima de 50 mg/mL frente a Staphylococcus aureus e 75 mg/mL contra Staphylococcus epidermidis e Escherichia coli e no teste de difusão em ágar, S. aureus apresentou maior sensibilidade ao extrato seco que as outras bactérias. O sabonete líquido mostrou maior eficiência na atividade anti-séptica contra as bactérias testadas na concentração de 100 mg de extrato/mL de sabonete.

  10. EPA se mueve hacia la prohibición de desengrasantes en aerosol y quitamanchas para lavado en seco como una de las primeras acciones reglamentarias conforme a la ley reformada de sustancias químicas

    Science.gov (United States)

    Comunicado de prensa de EPA: EPA se mueve hacia la prohibición de desengrasantes en aerosol y quitamanchas para lavado en seco como una de las primeras acciones reglamentarias conforme a la ley reformada de sustancias químicas

  11. Synthesis and anticancer cell potential of steroidal 16,17-seco-16,17a-dinitriles: identification of a selective inhibitor of hormone-independent breast cancer cells.

    Science.gov (United States)

    Nikolić, Andrea R; Petri, Edward T; Klisurić, Olivera R; Ćelić, Andjelka S; Jakimov, Dimitar S; Djurendić, Evgenija A; Penov Gaši, Katarina M; Sakač, Marija N

    2015-02-15

    We report the synthesis of steroidal 16,17-seco-16,17a-dinitriles and investigate their antitumor cell properties. Compounds were evaluated for anticancer potential by in vitro antiproliferation studies, molecular docking and virtual screening. Several compounds inhibit the growth of breast and prostate cancer cell lines (MCF-7, MDA-MB-231 and PC3), and/or cervical cancer cells (HeLa). Supporting this, molecular docking predicts that steroidal 16,17-seco-16,17a-dinitriles could bind with high affinity to multiple molecular targets of breast and prostate cancer treatment (aromatase, estrogen receptor α, androgen receptor and 17α-hydroxylase) facilitated by D-seco flexibility and nitrile-mediated contacts. Thus, 16,17-seco-16,17a-dinitriles may be useful for the design of inhibitors of multiple steroidogenesis pathways. Strikingly, 10, a 1,4-dien-3-on derivative, displayed selective submicromolar antiproliferative activity against hormone-dependent (MCF-7) and -independent (MDA-MB-231) breast cancer cells (IC50 0.52, 0.11μM, respectively). Ligand-based 3D similarity searches suggest AKR1C, 17β-HSD and/or 3β-HSD subfamilies as responsible for this antiproliferative activity, while fast molecular docking identified AKR1C and ERβ as potential binders-both targets in the treatment of hormone-independent breast cancers. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Geraniol hydroxylase and hydroxygeraniol oxidase activities of the CYP76 family of cytochrome P450 enzymes and potential for engineering the early steps of the (seco)iridoid pathway.

    NARCIS (Netherlands)

    Hofer, R.; Dong, L.; Andre, F.; Ginglinger, J.F.; Lugan, R.; Gavira, C.; Grec, S.; Lang, G.; Memelink, J.; Krol, van der A.R.; Bouwmeester, H.J.; Werck-Reichhart, D.

    2013-01-01

    The geraniol-derived (seco)iridoid skeleton is a precursor for a large group of bioactive compounds with diverse therapeutic applications, including the widely used anticancer molecule vinblastine. Despite of this economic prospect, the pathway leading to iridoid biosynthesis from geraniol is still

  13. La cátedra de estudios afrocolombianos: una posibilidad de descolonización del lenguaje en el Caribe seco colombiano

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    Ernell Villa

    2011-04-01

    Full Text Available En este trabajo se hace un reconocimiento a las apuestas que se desarrollan en una zona silenciada dentro de una región excluida. El Caribe seco es un lugar de la geografía colombiana donde las comunidades negras vienen desarrollando diferentes acciones para afirmar la vida desde la descolonización. El texto aborda el sentido pedagógico de la Cátedra de Estudios Afrocolombianos, a partir de prácticas culturales devaluadas. Inicialmente se hace una contextualización histórica, territorial, jurídica, educativa y organizativa, para insistir luego sobre la necesidad de generar una política de producción cultural desde las realidades de las comunidades negras.

  14. Holophyllane A: A Triterpenoid Possessing an Unprecedented B-nor-3,4-seco-17,14-friedo-lanostane Architecture from Abies holophylla

    Science.gov (United States)

    Kim, Chung Sub; Oh, Joonseok; Subedi, Lalita; Kim, Sun Yeou; Choi, Sang Un; Lee, Kang Ro

    2017-03-01

    A novel triterpenoid, holophyllane A (1), featuring a B-nor-3,4-seco-17,14-friedo-lanostane, along with its putative precursor, compound 2 were isolated from the methanol extract of the trunks of Abies holophylla. The 2D structure and relative configuration of 1 were initially determined via analysis of 1D and 2D NMR spectroscopic data and the assignment was confirmed by quantum mechanics-based NMR chemical shift calculations. The absolute configuration was established by comparison of the experimental and simulated ECD data generated at different theory levels. Compounds 1 and 2 exhibited moderate to weak cytotoxicity and significant inhibitory activity against nitric oxide (NO) production.

  15. Estudio del efecto del proceso de deshidratación osmótica en la obtención de trozos secos de carambola (averroha carambola l.)

    OpenAIRE

    Castillo Ortiz, Maria Eugenia; Cornejo Zuñiga, Fabiola Marcela

    2009-01-01

    En el presente trabajo se estudio el efecto del proceso de Deshidratación Osmótica en la obtención de trozos secos de carambola. Los experimentos realizados sirvieron para establecer la cinética de deshidratación osmótica a 3 concentraciones de sacarosa (40 ºBrix, 50ºBrix y 60ºBrix) y a presión atmosférica. Demostrándose que a 50ºBrix se obtiene el menor coeficiente de difusión de sólidos y una considerable perdida de agua. Por otro lado, que el aplicar deshidratación osmótica produce un aume...

  16. Caracterização físico-química do extrato fluido e seco por nebulização de Symphytum officinale L.

    OpenAIRE

    José Otávio Carréra Silva Júnior; José Luiz Fernandes Vieira; Wagner Luiz Ramos Barbosa; Newton Lindolfo Pereira

    2006-01-01

    O artigo reporta a obtenção do extrato fluido de Symphytum officinale L., e posterior secagem por nebulização, e a caracterização físico-química por técnicas termogravimétricas, espectroscópicas e cromatográficas. O adjuvante de secagem utilizado foi hidroxietilcelulose na concentração de 1,5%. Foi observado que o processo de secagem por nebulização, nas condições operacionais estabelecidas, não influenciou as características dos constituintes do extrato seco em relação ao extrato fluido pela...

  17. Lupin alkaloids. Part II. Some stereochemical aspects of multiflorine and seco(11,12)-12-dehydromultiflorine previously named N-methylalbine

    Science.gov (United States)

    Brukwicki, Tadeusz; Wysocka, Waleria

    1989-05-01

    From the 13C NMR spectra of multiflorine ( I), seco(11,12)-12-dehydromultiflorine ( II) and their monoperchlorates (in DMSO- d6), the conformation of rings B and C was determined. In the free base of I they are, boat-chair, whereas in the monocation of I as well as both in the free base and the monocation of II, they are chair, chair and chair respectively. The difference in conformation of the two free bases, I and II, is probably due to a repulsive interaction between the hydrogen pairs 8β-12β, 12β-17β and 14β-17β in the "chair" conformation in I. In I·H + a weak intramolecular hydrogen bond stabilizes the triple-chair conformation.

  18. Trichiconlides CF, four new limonoids with 1,2-seco phragmalin-type carbon skeleton from the fruits of Trichilia connaroides.

    Science.gov (United States)

    An, Fa-Liang; Sun, Dong-Mei; Wang, Xiao-Bing; Yang, Lei; Yin, Yong; Luo, Jun; Kong, Ling-Yi

    2018-03-01

    Phytochemical investigation of the fruits from Trichilia connaroides led to the isolation of four rare 1,2-seco phragmalin-type limonoids (1-4) with C-7/28 δ-lactone ring along with two known triterpenoids (5-6). An oxygen bridge between C-1 and C-2 formed an rare 9-oxa-tricyclo[3.3.2.1 7,10 ]undecane-2-ene moiety in structure of 1 and 2, and 3-4 possessed a bicyclo[5.2.1 4,10 ]decane skeleton. Their structures were established based on extensive spectroscopic methods and their absolute configurations of 1 were confirmed by TDDFT/ECD calculation and comparative analysis. Compounds 5-6 showed moderate inhibitory effects on Hela tumor cell lines with inhibition ratio values of 83.8% and 87.1% at concentration 40μM, respectively. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Estudio termoeconómico de diferentes configuraciones de ciclo combinado integrado con una planta solar

    Directory of Open Access Journals (Sweden)

    María Dolores Durán García

    2014-01-01

    Full Text Available Se presenta el análisis termoeconómico de una planta de ciclo combinado integrada con una planta solar de canal parabólico, considerada como una sección de la caldera de recuperación de calor, con el objetivo de conseguir un diseño óptimo al determinar los parámetros de diseño optimizados para ambos sistemas. Se aplica una metodología empleada en trabajos previos para la optimización de ciclos combinados, pero ahora con una planta solar. Como resultado, a partir de un análisis de sensibilidad, se obtiene el desempeño de varias configuraciones bajo diferentes condiciones de radiación solar.

  20. One-Year Behavioral Treatment of Obesity: Comparison of Moderate and Severe Caloric Restriction and the Effects of Weight Maintenance Therapy.

    Science.gov (United States)

    Wadden, Thomas A.; And Others

    1994-01-01

    Compared weight losses of 49 obese women assigned to 52-week behavioral program combined with moderate or severe caloric restriction. Those in severe caloric restriction group lost significantly more weight during first 26 weeks but regained some weight. Reports of binge eating declined in both groups, and no relationship was observed between…

  1. Caloric Intake from Fast Food among Children and Adolescents in the United States, 2011-2012. NCHS Data Brief. Number 213

    Science.gov (United States)

    Vikraman, Sundeep; Fryar, Cheryl D.; Ogden, Cynthia L.

    2015-01-01

    Consumption of fast food has been linked to weight gain in adults. Fast food has also been associated with higher caloric intake and poorer diet quality in children and adolescents. From 1994 through 2006, caloric intake from fast food increased from 10% to 13% among children aged 2-18 years. This report presents the most recent data on the…

  2. RELACIÓN ENTRE VARIABLES CLIMÁTICAS CON LA MORFOLOGÍA Y CONTENIDO DE ACEITE DE SEMILLAS DE HIGUERILLA (Ricinus communis L. DE CHIAPAS

    Directory of Open Access Journals (Sweden)

    María Antonieta Goytia-Jiménez

    2011-01-01

    Full Text Available Ciento cincuenta y un accesiones de higuerilla (Ricinus communis L., colectadas en el estado de Chiapas, México, fueron caracterizadas por contenido de aceite, forma, tamaño y peso de la semilla, con el objetivo de generar información que pueda servir de base en un programa de mejoramiento para esta especie, que podría ser una opción rentable para la producción de biodiesel y bioturbosina. De acuerdo con su distribución, se establecieron las cuatro siguientes zonas climáticas: Región 1 clima Lluvioso tropical sin estación seca; Región 2 Sabana tropical con inviernos secos; Región 3 Sabana tropical con inviernos menos secos que la Región 2, y Región 4 Lluvioso Tropical. Se encontró una amplia variación en tamaño (de 0.05 a 2.49 cm2, color, peso (desde 7 hasta 123.9 g por cada 100 semillas y contenido de aceite (desde 12.20 a 64.84 %. Las asociaciones que se establecieron entre el tamaño y peso de 100 semillas con temperatura y precipitación fueron negativas, y significativas sólo en las regiones 3 y 4. No hubo significancia para las asociaciones del contenido de aceite con temperatura y precipitación, pero la tendencia fue a ser positivas en las regiones 1 y 4, las de mayor humedad de las cuatro regiones, y negativas en las regiones 2 y 3. Se concluye que los individuos de esta especie presentan una gran adaptación a diferentes entornos y crean fenotipos especiales para cada lugar en donde se desarrollan.

  3. MICORRIZA ARBUSCULAR Y SU EFECTO EN PLÁNTULAS DE Elaeis guineensis (Palmaceae CON ALTO NIVEL DE FÓSFORO EN EL SUELO

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    Silvia Eugenia Barrera Berdugo

    2010-01-01

    Full Text Available Los hongos micorrizicos arbusculares (HMA facilitan la absorción de nutrientes a las plantas hospederas, por esta razón estos microorganismos cumplen un rol fundamental en el funcionamiento de los agroecosistemas. Con el fin de evaluar el efecto que tienen los HMA nativos y foráneos en Elaeis guineensis se realizó este experimento. Plantas de tres meses de edad fueron sometidas a cuatro tratamientos: IN, IF, Mixto y Testigo. Se evaluó peso seco total de la planta, peso seco raíz, peso seco parte aérea de la planta, altura de la planta, tasa de crecimiento relativo, porcentaje de colonización y número de esporas. Se hicieron tres muestreos, uno inicial, uno a los 45 días y otro a los 90 días. Los datos fueron analizados mediante un ANOVA o Kruskall-Wallis según el comportamiento de los datos, seguido de un test de medias de Duncan o un test modificado de Tuckey para datos no paramétricos. Se presentaron diferencias significativas en el número de esporas entre los tratamientos IN, IF, Mixto y el Testigo y entre IN y Mixto a los 45 días. En el porcentaje de colonización se observaron diferencias entre los tratamientos IF y Testigo a los 45 días. A los 90 días entre todos los tratamientos con respecto al testigo. A pesar de que el nivel de P en el suelo fue alto, también lo fue el porcentaje de colonización en las dos épocas evaluadas. A través del tiempo el tratamiento IN funcionó mejor en las condiciones edáficas del suelo usado en este experimento.

  4. A two year randomized controlled trial of human caloric restriction: feasibility and effects on predictors of health span and longevity

    Science.gov (United States)

    Background: Caloric restriction (CR), energy intake reduced below ad libitum (AL) intake, increases life span in many species. The implications for humans can be clarified by randomized controlled trials of CR. Methods: To determine CRs feasibility, safety, and effects on predictors of longevity, di...

  5. Caloric content of leaves of five tree species from the riparian vegetation in a forest fragment from South Brazil

    Directory of Open Access Journals (Sweden)

    Leandro Fabrício Fiori

    2015-09-01

    Full Text Available Abstract Aim: The measurement of the caloric content evidences the amount of energy that remains in the leaf and that can be released to the aquatic trophic chain. We assessed the energy content of leaves from five riparian tree species of a forest fragment in south Brazil and analyzed whether leaf caloric content varied between leaf species and between seasons (dry and wet. The studied sites are located in Northwest of Paraná State, inside a Semi-Deciduous Forest fragment beside two headwater streams. Methods Sampling sites were located along the riparian vegetation of these two water bodies, and due to its proximity and absence of statistical differences of caloric values, analyzed as one compartment. Results Caloric content varied significantly among species and among all pairs of species, with exception of Nectandra cuspidata Ness and Calophyllum brasiliensis Cambess. Two species presented significant differences between seasons, Sloanea guianensis (Aubl. Ben and Calophyllum brasiliensis Cambess. Conclusions The absence of significant seasonal differences of energy content for some species may be due to the characteristics of the tropical forest, in which temperature did not varied dramatically between seasons. However, the energy differed between species and seasons for some species, emphasizing the necessity of a preliminary inspection of energy content, before tracing energy fluxes instead of using a single value to all species from riparian vegetation.

  6. Short-term caloric restriction normalizes hypothalamic neuronal responsiveness to glucose ingestion in patients with type 2 diabetes

    NARCIS (Netherlands)

    Teeuwisse, W.M.; Widya, R.L.; Paulides, M.; Lamb, H.J.; Smit, J.W.A.; Roos, A. de; Buchem, M.A. van; Pijl, H.; Grond, J. van der

    2012-01-01

    The hypothalamus is critically involved in the regulation of feeding. Previous studies have shown that glucose ingestion inhibits hypothalamic neuronal activity. However, this was not observed in patients with type 2 diabetes. Restoring energy balance by reducing caloric intake and losing weight are

  7. Weight loss in obese men by caloric restriction and high-dose diazoxide-mediated insulin suppression.

    NARCIS (Netherlands)

    Boekel, G.A.J van; Loves, S.; Sorge, A van; Ruinemans-Koerts, J.; Rijnders, T.; Boer, H. de

    2008-01-01

    OBJECTIVE: To examine the concept whether high-dose diazoxide (DZX)-mediated insulin suppression, in combination with moderate caloric restriction and increased physical activity, can establish a weight loss of at least 15% in obese hyperinsulinaemic men. DESIGN: Open, uncontrolled, 6-month pilot

  8. Caloric Restriction in Lean and Obese Strains of Laboratory Rat: Effects on Body Composition, Metabolism, Growth, and Overall Health

    Science.gov (United States)

    NEW FINDINGS: What is the central question of this study? How do lean and obese rats respond physiologically to caloric restriction? What is the main finding and its importance? Obese rats show marked benefits compared with lean animals. Reduced body fat is associated with improv...

  9. Comparison of Vestibular Evoked Myogenic Potential and Caloric Tests Findings in Noise Induced Hearing Loss-Affected and Healthy Individuals

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    Farinoosh Fakharnia

    2010-06-01

    Full Text Available Background and Aim: Balance disturbance is one of the non-auditory effects of noisy industrial environments that is usually neglected. The aim of the current study was to investigate the effect of occupational noise on vestibular system among workers with noise-induced hearing loss (NIHL, based on both vestibular evoked myogenic potentials (VEMP and caloric tests.Methods: Thirty male workers with noise-induced hearing loss and thirty male matched controls were examined by VEMP and caloric tests. Study parameters included unilateral weakness, p13 and n23 latencies, and p13-n23 amplitude. Caloric test was performed only for 20 patients.Results: No significant difference was observed in unilateral weakness between the two groups. On the other hand, the difference in mean latencies of p13 in the right ear (p=0.003 and left ear (p=0.01 was significant between the two groups. However, the difference in n23 latency was significant only in the right ear (p=0.03. There was no significant difference between groups in p13-n23 amplitude.Conclusion: It seems that pars inferior of vestibule is the susceptible part in individuals with NIHL. In general, abnormal findings in both VEMP and caloric tests were more common compared to functional symptoms such as vertigo, which may be due to central compensation and the symmetry of the disorder.

  10. The effect of non-caloric sweeteners on cognition, choice, and post-consumption satisfaction.

    Science.gov (United States)

    Hill, Sarah E; Prokosch, Marjorie L; Morin, Amanda; Rodeheffer, Christopher D

    2014-12-01

    Consumers often turn to non-caloric sweeteners (NCS) as a means of promoting a healthy body weight. However, several studies have now linked their long-term use to increased weight gain, raising the question of whether these products produce unintended psychological, physiological, or behavioral changes that have implications for weight management goals. In the following, we present the results of three experiments bearing on this issue, testing whether NCS-consumption influences how individuals think about and respond to food. Participants in each of our three experiments were randomly assigned to consume a sugar-sweetened beverage, an unsweetened beverage, or a beverage sweetened with NCS. We then measured their cognition (Experiment 1), product choice (Experiment 2), and subjective responses to a sugar-sweetened food (Experiment 3). Results revealed that consuming NCS-sweetened beverages influences psychological processes in ways that - over time - may increase calorie intake. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Tunable magneto-caloric effect in Gd1-xTbx heterostructures thin film

    Science.gov (United States)

    Lambert, C. H.; El Hadri, M. S.; Hamedoun, M.; Benyoussef, A.; Mounkachi, O.; Mangin, S.

    2017-12-01

    The magnetic and magneto-caloric properties of (Gd1-xTbx) alloy thin films and [Gd/Tb] multilayers have been investigated. All the samples had a total thickness of 100 nm and were deposited by DC sputtering. By changing the composition of the system, the ordering temperature (Tc) and the magnetic entropy changes of the compounds could be tuned. The results show that the Tc of the alloy thin films is close to 270 K for x = 0.2. Moreover, creating [Gd/Tb] multilayers with the same thickness and concentration of the studied Gd80Tb20 alloy film enables to strongly increase the relative cooling power, and reach values twice as big as from the corresponding alloys. These results suggest that nanostructuring of [Gd/Tb] multilayers may be a promising route to tailor the magnetocaloric response of materials.

  12. Assessment of potentially harmful elements pollution in the Calore River basin (Southern Italy).

    Science.gov (United States)

    Zuzolo, Daniela; Cicchella, Domenico; Catani, Vittorio; Giaccio, Lucia; Guagliardi, Ilaria; Esposito, Libera; De Vivo, Benedetto

    2017-06-01

    The geographical distribution of concentration values for harmful elements was determined in the Campania region, Italy. The study area consists of the drainage basin of the River Calore, a tributary of the river Volturno, the largest Southern Italian river. The results provide reliable analytical data allowing a quantitative assessment of the trace element pollution threat to the ecosystem and human health. Altogether 562 stream sediment samples were collected at a sampling density of 1 site per 5 km2. All samples were air-dried, sieved to urban settlements and industrial areas. The enrichment factor of these elements is 3-4 times higher than the background values. The southwestern area of the basin is characterized by a moderate/high degree of contamination, just where the two busiest roads of the area run and the highest concentration of industries occurs.

  13. Effects of Caloric Restriction on Cardiovascular Aging in Non-human Primates and Humans

    Science.gov (United States)

    Cruzen, Christina; Colman, Ricki J.

    2009-01-01

    Synopsis Approximately one in three Americans has some form of cardiovascular disease (CVD), accounting for one of every 2.8 deaths in the United States in 2004. Two of the major risk factors for CVD are advancing age and obesity. An intervention able to positively impact both aging and obesity, such as caloric restriction (CR), may prove extremely useful in the fight against CVD. CR is the only environmental or lifestyle intervention that has repeatedly been shown to increase maximum life span and to retard aging in laboratory rodents. In this article, we review evidence that CR in nonhuman primates and humans has a positive effect on risk factors for CVD. PMID:19944270

  14. Aging and Caloric Restriction Research: A Biological Perspective With Translational Potential

    Directory of Open Access Journals (Sweden)

    Priya Balasubramanian

    2017-07-01

    Full Text Available Aging as a research pursuit is fairly new compared with traditional lines of medical research. A growing field of investigators is focused on understanding how changes in tissue biology, physiology, and systemic homeostasis, conspire to create increased vulnerability to disease as a function of age. Aging research as a discipline is necessarily broad; in part because aging itself is multi-faceted and in part because different model systems are employed to define the underlying biology. In this review we outline aspects of aging research that are likely to uncover the pivotal events leading to age-related disease vulnerability. We focus on studies of human aging and discuss the value of research on caloric restriction, an intervention with proven efficacy in delaying aging. We propose that studies such as these will deliver target factors and processes that create vulnerability in human aging, an advance that would potentially be transformative in clinical care.

  15. Caloric Restriction as a Strategy to Improve Vascular Dysfunction in Metabolic Disorders

    Directory of Open Access Journals (Sweden)

    Concha F. García-Prieto

    2016-06-01

    Full Text Available Caloric restriction (CR has proved to be the most effective and reproducible dietary intervention to increase healthy lifespan and aging. A reduction in cardiovascular disease (CVD risk in obese subjects can be already achieved by a moderate and sustainable weight loss. Since pharmacological approaches for body weight reduction have, at present, a poor long-term efficacy, CR is of great interest in the prevention and/or reduction of CVD associated with obesity. Other dietary strategies changing specific macronutrients, such as altering carbohydrates, protein content or diet glycemic index have been also shown to decrease the progression of CVD in obese patients. In this review, we will focus on the positive effects and possible mechanisms of action of these strategies on vascular dysfunction.

  16. Repletion of TNFα or leptin in calorically restricted mice suppresses post-restriction hyperphagia

    Directory of Open Access Journals (Sweden)

    Catherine Hambly

    2012-01-01

    The causes of post-restriction hyperphagia (PRH represent a target for drug-based therapies to prevent obesity. However, the factors causing PRH are poorly understood. We show that, in mice, the extent of PRH was independent of the time under restriction, but depended on its severity, suggesting that PRH was driven by signals from altered body composition. Signals related to fat mass were important drivers. Circulating levels of leptin and TNFα were significantly depleted following caloric restriction (CR. We experimentally repleted their levels to match those of controls, and found that in both treatment groups the level of PRH was significantly blunted. These data establish a role for TNFα and leptin in the non-pathological regulation of energy homeostasis. Signals from adipose tissue, including but not limited to leptin and TNFα, regulate PRH and might be targets for therapies that support people engaged in CR to reduce obesity.

  17. Caloric restriction suppresses apoptotic cell death in the mammalian cochlea and leads to prevention of presbycusis.

    Science.gov (United States)

    Someya, Shinichi; Yamasoba, Tatsuya; Weindruch, Richard; Prolla, Tomas A; Tanokura, Masaru

    2007-10-01

    Presbycusis is characterized by an age-related progressive decline of auditory function, and arises mainly from the degeneration of hair cells or spiral ganglion (SG) cells in the cochlea. Here we show that caloric restriction suppresses apoptotic cell death in the mouse cochlea and prevents late onset of presbycusis. Calorie restricted (CR) mice, which maintained body weight at the same level as that of young control (YC) mice, retained normal hearing and showed no cochlear degeneration. CR mice also showed a significant reduction in the number of TUNEL-positive cells and cleaved caspase-3-positive cells relative to middle-age control (MC) mice. Microarray analysis revealed that CR down-regulated the expression of 24 apoptotic genes, including Bak and Bim. Taken together, our findings suggest that loss of critical cells through apoptosis is an important mechanism of presbycusis in mammals, and that CR can retard this process by suppressing apoptosis in the inner ear tissue.

  18. Adiabatic measurements of magneto-caloric effects in pulsed high magnetic fields up to 55 T

    Science.gov (United States)

    Kihara, T.; Kohama, Y.; Hashimoto, Y.; Katsumoto, S.; Tokunaga, M.

    2013-07-01

    Magneto-caloric effects (MCEs) measurement system in adiabatic condition is proposed to investigate the thermodynamic properties in pulsed magnetic fields up to 55 T. With taking the advantage of the fast field-sweep rate in pulsed field, adiabatic measurements of MCEs were carried out at various temperatures. To obtain the prompt response of the thermometer in the pulsed field, a thin film thermometer is grown directly on the sample surfaces. The validity of the present setup was demonstrated in the wide temperature range through the measurements on Gd at about room temperature and on Gd3Ga5O12 at low temperatures. The both results show reasonable agreement with the data reported earlier. By comparing the MCE data with the specific heat data, we could estimate the entropy as functions of magnetic field and temperature. The results demonstrate the possibility that our approach can trace the change in transition temperature caused by the external field.

  19. Repletion of TNFα or leptin in calorically restricted mice suppresses post-restriction hyperphagia

    Science.gov (United States)

    Hambly, Catherine; Duncan, Jacqueline S.; Archer, Zoë A.; Moar, Kim M.; Mercer, Julian G.; Speakman, John R.

    2012-01-01

    SUMMARY The causes of post-restriction hyperphagia (PRH) represent a target for drug-based therapies to prevent obesity. However, the factors causing PRH are poorly understood. We show that, in mice, the extent of PRH was independent of the time under restriction, but depended on its severity, suggesting that PRH was driven by signals from altered body composition. Signals related to fat mass were important drivers. Circulating levels of leptin and TNFα were significantly depleted following caloric restriction (CR). We experimentally repleted their levels to match those of controls, and found that in both treatment groups the level of PRH was significantly blunted. These data establish a role for TNFα and leptin in the non-pathological regulation of energy homeostasis. Signals from adipose tissue, including but not limited to leptin and TNFα, regulate PRH and might be targets for therapies that support people engaged in CR to reduce obesity. PMID:21954068

  20. Neuroimaging Biomarkers of Caloric Restriction on Brain Metabolic and Vascular Functions.

    Science.gov (United States)

    Lin, Ai-Ling; Parikh, Ishita; Hoffman, Jared D; Ma, David

    2017-03-01

    Non-invasive neuroimaging methods have been developed as powerful tools for identifying in vivo brain functions for studies in humans and animals. Here we review the imaging biomarkers that are being used to determine the changes within brain metabolic and vascular functions induced by caloric restriction (CR), and their potential usefulness for future studies with dietary interventions in humans. CR causes an early shift in brain metabolism of glucose to ketone bodies, and enhances ATP production, neuronal activity and cerebral blood flow (CBF). With age, CR preserves mitochondrial activity, neurotransmission, CBF, and spatial memory. CR also reduces anxiety in aging mice. Neuroimaging studies in humans show that CR restores abnormal brain activity in the amygdala of women with obesity and enhances brain connectivity in old adults. Neuroimaging methods have excellent translational values and can be widely applied in future studies to identify dietary effects on brain functions in humans.

  1. Influencia del Calor Aportado y Metal de Aporte Sobre las Propiedades Mecánicas y la Microestructura de Juntas Soldadas por FCAW de Acero Microaleado de Alta Resistencia

    Directory of Open Access Journals (Sweden)

    César Marconi

    2015-06-01

    Full Text Available ResumenActualmente, los aceros microaleados son ampliamente utilizados en reemplazo de los aceros al C y C-Mn por sus ventajas en cuanto a propiedades mecánicas, resistencia a la corrosión y soldabilidad, permitiendo una reducción de peso de los vehículos y estructuras sin detrimento de su resistencia. Cuando estos aceros son soldados, el ciclo térmico de la soldadura provoca cambios microestructurales que modifican sus propiedades originales. El calor aportado (HI: heat input es una de las principales variables a tener en cuenta cuando se evalúan estas modificaciones. Las propiedades finales de la unión soldada también se definen por el tipo de consumible utilizado. El objetivo de este trabajo es analizar las propiedades mecánicas y la microestructura de juntas soldadas a tope de un acero microaleado con dos grados de metal de aporte y diferentes HI. Como resultado del trabajo se observó un aumento considerable de tamaño de grano en la ZAC adyacente a la línea de fusión para todas las condiciones, siendo este efecto más marcado cuando se soldó con alto HI; y un ablandamiento en la ZAC de grano fino. Prácticamente se mantuvieron los valores de resistencia a la tracción al soldar con ambos consumibles, con un mejor desempeño cuando se soldó con bajo HI. La tenacidad en la ZAC mejoró con la disminución del HI.

  2. Acute caloric restriction counteracts hepatic bile acid and cholesterol deficiency in morbid obesity.

    Science.gov (United States)

    Straniero, S; Rosqvist, F; Edholm, D; Ahlström, H; Kullberg, J; Sundbom, M; Risérus, U; Rudling, M

    2017-05-01

    Bile acid (BA) synthesis is regulated by BA signalling in the liver and by fibroblast growth factor 19 (FGF19), synthesized and released from the intestine. In morbid obesity, faecal excretion and hepatic synthesis of BAs and cholesterol are strongly induced and caloric restriction reduces their faecal excretion considerably. We hypothesized that the high intestinal food mass in morbidly obese subjects promotes faecal excretion of BAs and cholesterol, thereby creating a shortage of both BAs and cholesterol in the liver. Ten morbidly obese women (BMI 42 ± 2.6 kg m-2 ) were monitored on days 0, 3, 7, 14 and 28 after beginning a low-calorie diet (800-1100 kcal day-1 ). Serum was collected and liver size and fat content determined. Synthesis of BAs and cholesterol was evaluated from serum markers, and the serum levels of lipoproteins, BAs, proprotein convertase subtilisin/kexin type 9 (PCSK9), insulin, glucose and FGF19 were monitored. Fifty-four nonobese women (BMI cholesterol and serum levels of BAs and PCSK9 were elevated in the obese group compared to controls. Already after 3 days on a low-calorie diet, BA and cholesterol synthesis and serum BA and PCSK9 levels normalized, whereas LDL cholesterol increased. FGF19 and triglyceride levels were unchanged, and liver volume was reduced by 10%. The results suggest that hepatic BAs and cholesterol are deficient in morbid obesity. Caloric restriction rapidly counteracts these deficiencies, normalizing BA and cholesterol synthesis and circulating PCSK9 levels, indicating that overproduction of cholesterol in enlarged peripheral tissues cannot explain this phenotype. We propose that excessive food intake promotes faecal loss of BAs and cholesterol contributing to their hepatic deficiencies. © 2017 The Authors. Journal of Internal Medicine published by John Wiley & Sons Ltd on behalf of Association for Publication of The Journal of Internal Medicine.

  3. Cognitive performances are selectively enhanced during chronic caloric restriction or resveratrol supplementation in a primate.

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    Alexandre Dal-Pan

    Full Text Available Effects of an 18-month treatment with a moderate, chronic caloric restriction (CR or an oral supplementation with resveratrol (RSV, a potential CR mimetic, on cognitive and motor performances were studied in non-human primates, grey mouse lemurs (Microcebus murinus.Thirty-three adult male mouse lemurs were assigned to three different groups: a control (CTL group fed ad libitum, a CR group fed 70% of the CTL caloric intake, and an RSV group (RSV supplementation of 200 mg.kg(-1.day(-1 fed ad libitum. Three different cognitive tests, two motor tests, one emotional test and an analysis of cortisol level were performed in each group.Compared to CTL animals, CR or RSV animals did not show any change in motor performances evaluated by rotarod and jump tests, but an increase in spontaneous locomotor activity was observed in both groups. Working memory was improved by both treatments in the spontaneous alternation task. Despite a trend for CR group, only RSV supplementation increased spatial memory performances in the circular platform task. Finally, none of these treatments induced additional stress to the animals as reflected by similar results in the open field test and cortisol analyses compared to CTL animals.The present data provided the earliest evidence for a beneficial effect of CR or RSV supplementation on specific cognitive functions in a primate. Taken together, these results suggest that RSV could be a good candidate to mimic long-term CR effects and support the growing evidences that nutritional interventions can have beneficial effects on brain functions even in adults.

  4. Cognitive Performances Are Selectively Enhanced during Chronic Caloric Restriction or Resveratrol Supplementation in a Primate

    Science.gov (United States)

    Marchal, Julia; Picq, Jean-Luc; Aujard, Fabienne

    2011-01-01

    Effects of an 18-month treatment with a moderate, chronic caloric restriction (CR) or an oral supplementation with resveratrol (RSV), a potential CR mimetic, on cognitive and motor performances were studied in non-human primates, grey mouse lemurs (Microcebus murinus). Thirty-three adult male mouse lemurs were assigned to three different groups: a control (CTL) group fed ad libitum, a CR group fed 70% of the CTL caloric intake, and an RSV group (RSV supplementation of 200 mg.kg−1.day−1) fed ad libitum. Three different cognitive tests, two motor tests, one emotional test and an analysis of cortisol level were performed in each group. Compared to CTL animals, CR or RSV animals did not show any change in motor performances evaluated by rotarod and jump tests, but an increase in spontaneous locomotor activity was observed in both groups. Working memory was improved by both treatments in the spontaneous alternation task. Despite a trend for CR group, only RSV supplementation increased spatial memory performances in the circular platform task. Finally, none of these treatments induced additional stress to the animals as reflected by similar results in the open field test and cortisol analyses compared to CTL animals. The present data provided the earliest evidence for a beneficial effect of CR or RSV supplementation on specific cognitive functions in a primate. Taken together, these results suggest that RSV could be a good candidate to mimic long-term CR effects and support the growing evidences that nutritional interventions can have beneficial effects on brain functions even in adults. PMID:21304942

  5. Effects of caloric restriction on nitrogen and carbon stable isotope ratios in adult rat bone.

    Science.gov (United States)

    Robertson, Kimberly L; Rowland, Neil E; Krigbaum, John

    2014-10-15

    Stable isotope analysis is a valuable technique for dietary estimation in ecological and archaeological research, yet many variables can potentially affect tissue stable isotope signatures. Controlled feeding studies across a range of species have consistently demonstrated impacts of caloric restriction on tissue stable isotope ratios, but most have focused on juvenile, fasting, and/or starving individuals, and most have utilized soft tissues despite the importance of bone for paleodietary analyses. The goal of this study was to determine whether temporally defined, moderate food restriction could affect stable carbon and/or nitrogen isotope ratios in adult mammalian bone - a tissue that arguably reflects long-term dietary signals. Adult rats fed a standard laboratory diet were restricted to 45% of ad libitum intakes for 3 or 6 months. Relevant anatomical and physiological parameters were measured to confirm that the restriction protocol resulted in significant nutritional stress and to provide independent data to facilitate interpretation of stable isotope ratios. Femoral bone δ(13)Ccollagen, δ(15)Ncollagen, and δ(13)Capatite values were determined by isotope ratio mass spectrometry. Calorie-restricted animals exhibited a small, yet significant enrichment in (15)Ncollagen compared with control animals, reflecting protein-calorie stress. While the δ(13)Ccollagen values did not differ, the δ(13)Capatite values revealed less enrichment in (13)C than in controls, reflecting catabolism of body fat. Independent anatomical and physiological data from these same individuals support these interpretations. Results indicate that moderate caloric restriction does not appreciably undermine broad interpretations of dietary signals in adult mammalian bone. Significant variability among individuals or groups, however, is best explained by marked differences in energy intake over variable timescales. An inverse relationship between the δ(13)Capatite and δ(15)Ncollagen

  6. Caloric intake during the perioperative period and growth failure in infants with congenital heart disease.

    Science.gov (United States)

    Nicholson, George T; Clabby, Martha L; Kanter, Kirk R; Mahle, William T

    2013-02-01

    Infants with congenital heart disease have impaired weight gain during the first several months of life. Efforts have focused on improving weight gain and nutritional status during the first months of life. Close examination of the data suggests that the immediate postoperative period is problematic. Etiology of this early growth failure should be identified to develop effective interventions. This is a retrospective study of neonates who underwent modified systemic-to-pulmonary artery shunt, including Norwood palliation, at Children's Healthcare of Atlanta between January 2009 and July 2011. We analyzed growth from time of surgical intervention to hospital discharge. Measures of calculated weight-for-age Z-score (WAZ score) were performed using the World Health Organization's Anthro Software (version 3.2.2, January 2011; WHO, Geneva, Switzerland). Seventy-three patients were identified. Eight patients did not meet inclusion criteria. Complete data were collected on the remaining 65 patients. Median caloric intake patients received was 50.4 [interquartile range (IQR) 41.6 to 63.6] calories/kg/day while exclusively on parental nutrition. At hospital discharge, the median WAZ score was -2.0 (IQR -2.7 to -1.2) representing an overall median WAZ score decrease of -1.3 (IQR -1.7 to -0.7) from time of shunt palliation to hospital discharge. Despite studies showing poor weight gain in infants with congenital heart disease after neonatal palliation, this study reports the impact of hospital-based nutritional practices on weight gain in infants during the immediate postoperative period. Our data demonstrate that actual caloric intake during the cardiac intensive care unit stay is substantially below what is recommended.

  7. Effects of caloric restriction and overnight fasting on cycling endurance performance.

    Science.gov (United States)

    Ferguson, Lisa M; Rossi, Kelly A; Ward, Emily; Jadwin, Emily; Miller, Todd A; Miller, Wayne C

    2009-03-01

    In addition to aerobic endurance and anaerobic capacity, high power-to-weight ratio (PWR) is important for cycling performance. Cyclists often try to lose weight before race season to improve body composition and optimize PWR. Research has demonstrated body fat-reducing benefits of exercise after fasting overnight. We hypothesized that fasted-state exercise in calorie-restricted trained cyclists would not result in performance decrements and that their PWR would improve significantly. We also hypothesized that substrate use during fasted-state submaximal endurance cycling would shift to greater reliance on fat. Ten trained, competitive cyclists completed a protocol consisting of baseline testing, 3 weeks of caloric restriction (CR), and post-CR testing. The testing sessions measured pre- and post-CR values for resting metabolic rate (RMR), body composition, VO2, PWR and power-to-lean weight ratio (PLWR), and power output, as well as 2-hour submaximal cycling performance, rating of perceived exertion (RPE), and respiratory exchange ratio (RER). There were no significant differences between baseline and post-CR for submaximal trial RER, power output, VO2, RMR, VO2max, or workload at VO2max. However, RPE was significantly lower, and PWR was significantly higher post-CR, whereas RER did not change. The cyclists' PWR and body composition improved significantly, and their overall weight, fat weight, and body fat percentage decreased. Lean mass was maintained. The cyclists' RPE decreased significantly during 2 hours of submaximal cycling post-CR, and there was no decrement in submaximal or maximal cycling performance after 3 weeks of CR combined with overnight fasting. Caloric restriction (up to 40% for 3 weeks) and exercising after fasting overnight can improve a cyclist's PWR without compromising endurance cycling performance.

  8. Respostas termorregulatórias de crianças no exercício em ambiente de calor Respuestas termorreguladoras de niños en el ejercicio en ambiente de calor Thermoregulatory responses of children exercising in a hot environment

    Directory of Open Access Journals (Sweden)

    Luis Henrique L. S. Gomes

    2013-03-01

    calor. FUENTES DE DATOS: Se realizó una revisión de 47 artículos publicados entre 1960 y 2011 en las bases de datos electrónicas MedLine y SciELO Brasil, con el uso de los siguientes descriptores: "niños", "calor", "sudoración", "termorregulación", "glándula sudorípara" y "ejercicio", siendo usados aisladamente o en combinación, además de una tesis doctoral sobre el tema. SÍNTESIS DE LOS DATOS: En pre-púberes, la tasa de sudoración durante el esfuerzo es menor en comparación a los adultos. Niños poseen características termorreguladoras diferenciadas, presentando un débito de sudor por glándula mucho menor. La mayor razón entre área de superficie y masa corporal hace que los niños absorban más calor durante el ejercicio bajo estrés térmico, elevando el riesgo de presentar síntomas de hipertermia. El mayor flujo de sangre para la piel contribuye con un mejor control de la homeostasis térmica de niños. El menor tamaño de la glándula, la menor sensibilidad colinérgica, los niveles bajos de catecolaminas circulantes durante el esfuerzo y la falta de hormona androgénica explican la ocurrencia de la baja eliminación de sudor en el ejercicio realizado por niños. CONCLUSIONES: Niños exhiben glándulas sudoríparas inmaturas. Así, la práctica de actividad física combinada a altas temperaturas no es bien tolerada por el público infantojuvenil, que presenta mayor vulnerabilidad a las lesiones térmicas. En el calor, se debe tener un control riguroso de la ingestión de líquidos y una monitoración atenta de las condiciones climáticas para mayor seguridad en la práctica de ejercicios.OBJECTIVE: To review possible peculiarities in biological mechanisms related to responses of thermoregulatory and specific sweat glands in exercise performed by children in hot environments. DATA SOURCES: Review of 47 articles published between 1960 and 2011 in the electronic databases MedLine and SciELO Brazil using the following key-words: 'children', 'heat

  9. con turbinas de disco con paletas planas

    Directory of Open Access Journals (Sweden)

    D. García-Cortés

    2006-01-01

    Full Text Available Las turbinas de disco con paletas planas son los impelentes de flujo radial más ampliamente utilizados en la industria por constituir el impelente que forma parte de la configuración geométrica estándar para obtener este patrón de flujo en los tanques agitados. El estudio detallado de la hidrodinámica en este sistema de agitación es fundamental para continuar obteniendo conocimientos básicos imprescindibles para la síntesis y la modelación matemática de diferentes procesos complejos que se llevan a cabo en los tanques agitados, por ejemplo, la cristalización esférica. El propósito de este artículo es hacer una revisión de la información publicada sobre la hidrodinámica y la modelación matemática de la dinámica de fluidos en los tanques agitados con turbinas de disco con paletas planas y señalar los avances logrados en cada uno de los aspectos abordados y aquellos en los cuales es necesario seguir investigando.

  10. CARACTERIZACIÓN DE LA COBERTURA ARBÓREA EN UNA PASTURA DEL TRÓPICO SECO EN TOLIMA, COLOMBIA

    Directory of Open Access Journals (Sweden)

    Jorge Rodrigo Serrano

    2014-01-01

    Full Text Available El obje- tivo de este estudio fue caracterizar la vegetación leñosa perenne de un potrero arbolado del Magdalena Tolimense en Colombia. El inventario forestal se realizó mediante el establecimiento de parcelas temporales de muestreo. La estimación del porcentaje de oclusión de la copa de los árboles se obtuvo mediante fotografías digitales al cenit y su análisis en el software libre Gap Light Analyzer. La radicación fotosintéticamente activa (RAFA transmitida por la copa se midió con un ceptómetro Accupar LP-80. Se encontraron 21 especies leñosas perennes en un área de muestreo de 54 ha. Con menor porcentaje de oclusión fueron: Pseudosamanea guachapele (64% y Prosopis juliflora (63%, lo que sugiere incluirlas en diseños de sistemas silvopastoriles; algunas es pecies poseen potencial maderable como ingreso adicional al ganadero. Se encontró una importante diversidad de especies leñosas para ser introducidas en pasturas, sin perjudicar la producción de materia seca comestible para el ganado.

  11. PUDRICIÓN BASAL CAUSADA POR Phytophthora capsici EN PLANTAS DE CHILE TRATADAS CON VERMICOMPOST

    Directory of Open Access Journals (Sweden)

    Lidieth Uribe-Lor\\u00EDo

    2014-01-01

    Full Text Available Pudrición basal causada por Phytophthora capcisi en plantas de chile tratadas con vermicompost. El objetivo de este trabajo fue evaluar a nivel de invernadero el efecto de vermicompost sobre la incidencia y severidad de Phytophthora capcisi en plantas de chile (Capsicum annuum. Esta investigación se realizó entre febrero y marzo del 2012 en el Centro de Investigaciones Agronómicas, Sabanilla, San José, Costa Rica. Se utilizó un diseño completamente al azar con cuatro repeticiones y ocho plantas por unidad experimental en un arreglo factorial con los factores de dosis (0, 25% y 50% v/v vermicompost:suelo e inoculación (0 y 500 zoosporas por gramo de suelo. Se trasplantaron plántulas de 35 días, que fueron inoculadas dos semanas después del trasplante. La aplicación de vermicompost provocó un aumento significativo del peso fresco foliar y del peso seco foliar y radical; a mayor dosis, mayor fue el incremento. Las plantas de todos los tratamientos que incluyeron inoculación con P. capsici presentaron síntomas de la enfermedad en la raíz. Los valores de incidencia y severidad fueron mayores para el tratamiento con 50% de abono. En este tratamiento se presentaron síntomas de marchitez. La ausencia de diferencias en las variables de peso fresco y seco entre los tratamientos inoculados y sin inocular, a los que se adicionó abono al 25%, sugiere que esta dosis podría compensar el daño causado por el patógeno. Se observó una menor concentración de nutrimentos en los tejidos de las plantas inoculadas lo que indica que el daño causado a la raíz pudo haber afectado la adquisición de nutrimentos.

  12. Low-versus high-glycemic index diets in women: effects on caloric requirement, substrate utilization and insulin sensitivity.

    Science.gov (United States)

    Clapp, James F; Lopez, Beth

    2007-09-01

    Lowering dietary glycemic index appears to have positive health effects in obese and/or insulin resistant individuals. However, detailed studies in lean young men show no effect. This study was designed to test the null hypothesis that a diet rich in low-glycemic carbohydrate has no effect on lipid profile, caloric requirements, fat oxidation, or insulin sensitivity in adult women when compared to one rich in high-glycemic carbohydrate. The metabolic feeding protocol used was conducted in both a free-living and in-patient setting using a randomized crossover design. Seven women were studied on each of 2 diets in which 60% of the calories were from either high- or low-glycemic carbohydrate sources. Each diet lasted 20 days with measurements of caloric requirement, resting metabolic rate, glucose and insulin responses to diet and activity, insulin sensitivity, and lipid profile over the last 7 days. Caloric requirement was determined by bomb calorimetry. Other techniques included indirect calorimetry, hydrodensitometry, stable isotope tracers, and the euglycemic clamp. On the low-glycemic index diet the women's caloric requirements were 11% +/- 1% higher, fat oxidation at fasted rest supplied an average of 45% +/- 4% versus 28% +/- 5% of oxidative requirements, average glucose and insulin levels were approximately 40% lower, low density lipoproteins (LDL) and leptin concentrations were lower, and various indices of insulin sensitivity were > 20% higher. In this group of adult women, a diet that lowered glycemic index well below that typically found in western diets increased both daily caloric requirement and fat oxidation, decreased insulin and glucose concentrations and increased insulin sensitivity.

  13. Etmoiditis complicada con celulitis orbitaria en un lactante

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    Odette Pantoja Pereda

    Full Text Available Se define la etmoiditis como la inflamación e infección de la mucosa de las celdas etmoidales. Se diagnostica clínicamente con la presencia de edema en el ángulo medial del ojo, que se extiende a las estructuras adyacentes. Estudios imagenológicos son necesarios para verificar la presencia de complicaciones, entre las que se citan el absceso orbitario, subperióstico, epidural, subdural, cerebral, tromboflebitis del seno cavernoso, meningoencefalitis y la muerte del paciente. Streptococcus pneumoniae, Staphylococcus aureus y Haemophilus influenzae son microorganismos frecuentemente responsables de este cuadro. Las complicaciones orbitarias en las etmoiditis, necesitan el diagnóstico y tratamiento precoz para evitar secuelas irreversibles. Se presenta el caso de un lactante masculino, de 1 mes y 26 días de nacido, que ingresa con fiebre, rinorrea serosa y rechazo al alimento. Evolutivamente se constata marcada obstrucción nasal, edema periorbitario izquierdo, rubor, calor, protrusión del globo ocular e irritabilidad, y se diagnostica etmoiditis complicada con celulitis orbitaria. Se realiza tomografía axial computarizada que informa seno etmoidal izquierdo ocupado por contenido de densidad líquida con celularidad (15-25 UH, engrosamiento de partes blandas de la pared interna de la órbita que abomba, comprime y desplaza la musculatura orbitaria, y se extiende al párpado y al ala izquierda de la nariz desviando tabique blando; así como ligera proptosis, y disminución de la densidad ósea de la pared interna de la cavidad orbitaria. Se toma muestra para cultivo y se aísla Staphylococcus aureus meticillin resistente. Se comentan los elementos diagnósticos y su tratamiento, con el objetivo de llamar la atención de los pediatras para lograr el diagnóstico y tratamiento oportuno.

  14. Videojuego con Realidad Virtual

    OpenAIRE

    González Mora, César

    2017-01-01

    El objetivo del proyecto es el desarrollo de un videojuego deportivo que utilice realidad mixta. El videojuego se podrá utilizar con dispositivos de tipo cardboard, y utilizará realidad aumentada para la interacción del jugador con el videojuego. En el desarrollo se utilizará el motor Unity para conseguir una aplicación multiplataforma, y la librería Vuforia para implementar realidad mixta.

  15. Sistemas integrados con Arduino

    OpenAIRE

    EL YAKOUTI, MOHAMMED

    2017-01-01

    Design of a robot prototype remotely controllable from Bluetooth using Arduino. Control and testing of sensors and events interacting with Arduino and Bluetooth. Diseño de un prototipo de robot controlable remotamente con Bluetooth utilizando Arduino. Control y verificación de los sensores y eventos que interactúan mediante el Arduino y el Bluetooth. El Yakouti, M. (2017). Sistemas integrados con Arduino. http://hdl.handle.net/10251/89274. TFGM

  16. Variación espacial y estacional de grupos funcionales de bacterias cultivables del suelo de un bosque tropical seco en México Spatial and seasonal variation of soil culturable-bacterial functional groups in a Mexican tropical dry forest

    Directory of Open Access Journals (Sweden)

    Noé Manuel Montaño

    2013-03-01

    Full Text Available Los bosques tropicales secos tienen una amplia heterogeneidad ambiental y por lo tanto se podría esperar una variación temporal y espacial en la abundancia y tipo de grupos bacterianos activos. Se evaluó, durante dos años consecutivos, el efecto de la estacionalidad de la lluvia sobre algunos grupos bacterianos cultivables y nutrimentos del suelo en dos posiciones topográficas (crestas vs laderas en el bosque tropical seco, Chamela Jalisco, México. La hipótesis fue que la variación temporal y espacial de la disponibilidad de recursos afectaría la abundancia de los grupos bacterianos funcionales (heterótrofas totales, celulolíticas, solubilizadores de fosfatos y nitrificantes del suelo. En las crestas, el suelo fue más orgánico y con mayor concentración de nutrimentos totales y C orgánico lábil que en la ladera, registrando más bacterias heterótrofas y solubilizadoras de fosfato. En ambas posiciones topográficas la concentración de C y nutrimentos, así como el número de bacterias heterótrofas y solubilizadoras de P, decrecieron de la estación seca a la lluviosa en ambos años. En contraste, las bacterias nitrificantes fueron mayores en el suelo de la ladera, y al igual que las celulolíticas, tuvieron un patrón estacional opuesto a las bacterias heterótrofas, asociado a la disminución del C lábil y de la calidad de la materia orgánica. En conclusión, se sugiere que el relieve, la estacionalidad y la variación inter-anual de la lluvia regulan interactivamente la relación entre el C disponible y la estructura de las comunidades bacterianas del suelo en el bosque tropical seco de Chamela.Microbial biomass and activity in soils are frequently studied in tropical dry forests, but scarce information is available about the relationships between functional bacterial groups and soil fertility, where relief interacts with rainfall seasonality. The culturable-bacterial groups and nutrients were studied during two consecutive

  17. Investigando con personas con dificultades de aprendizaje

    Directory of Open Access Journals (Sweden)

    Borja González Luna

    2013-12-01

    Full Text Available El artículo muestra los orígenes de lo que Walmsley (2008 denomina «investigación inclusiva». Para comprender qué se entiende por investigación inclusiva tenemos que remontarnos a los debates epistemológicos sobre las metodologías cuantitativas y cualitativas, acontecidos en la década de los 90, en torno a la revista Disability & Society. A partir de una síntesis de dichos debates, focalizados en el ámbito de la «discapacidad intelectual y del desarrollo», se exponen dos estrategias de colaboración con dicha población: a una aproximación etnográfica (de trabajo grupal, y b una aproximación biográfica (de trabajo individual. A continuación se esboza un posible diseño de trabajo de campo que intenta superar el paradigma cualitativo «clásico» con el objetivo de incluir a dicho colectivo más allá del rol de «sujetos de la investigación». Para finalizar se recoge el debate sobre la accesibilidad de los resultados de la investigación a los participantes en dichas investigaciones, y con ello la necesaria innovación en el ámbito de las «devoluciones» de los resultados, cuando se trata de incluir a personas que presentan limitaciones para la comprensión del lenguaje abstracto oral y/o escrito.

  18. Interpretação e utilidade da prova calórica Interpretation and use of caloric testing

    Directory of Open Access Journals (Sweden)

    Denise Utsch Gonçalves

    2008-06-01

    Full Text Available A prova calórica é o teste da avaliação otoneurológica que verifica a integridade do reflexo vestíbulo-ocular e possibilita avaliar cada labirinto separadamente. Os principais aspectos relacionados à realização, interpretação e utilidade da prova calórica foram revistos. MÉTODOS: Realizou-se revisão sistemática sobre as publicações ocorridas nos últimos cem anos sobre o assunto. Incluíram-se artigos originais transversais e longitudinais, de revisão e meta-análise. Excluíram-se revisões de papeleta, relatos de caso e editoriais. Os descritores utilizados foram: prova calórica, nistagmo, sistema vestibular, preponderância direcional, predomínio labiríntico, teste calórico monotermal, teste calórico com água gelada, fenômeno de Bell. Pesquisou-se as bases de dados COCHRAINE, MEDLINE, LILACS, CAPES. RESULTADOS: De 818 resumos de artigos, selecionou-se inicialmente 93 que preenchiam os critérios de inclusão. A leitura dos artigos resultou na seleção final de 55. Na análise dos artigos, enfatizou-se na discussão fundamentos da prova calórica, tipos de estimulação utilizados, prova calórica monotermal e com água gelada, questões relacionadas à interpretação dos resultados, variáveis e artefatos. COMENTÁRIOS FINAIS: os valores de referência utilizados na prova calórica podem variar de serviço para serviço, com ponto de corte definido a partir de estudos locais. Semiotécnica cuidadosa é fundamental para elevar a sensibilidade do exame.Caloric testing is an otoneurologic evaluation of the status of the vestibular-ocular reflex; it allows an evaluation of each labyrinth separately. The main aspects on the use and interpretation of caloric testing are reviewed. METHOD: A systematic review of papers published in the past one hundred years on caloric testing was undertaken. The inclusion criteria were: cross-sectional, longitudinal, original articles, reviews and meta-analyses. Reviews of patient charts

  19. Determinación experimental mediante DSC de las estabilidades térmicas y las capacidades caloríficas: quinua, kiwicha y cañihua

    OpenAIRE

    Romero Carrión, Violeta; Tirado Rengifo, Arminda; Dávalos Prado, Juan

    2015-01-01

    El objetivo fue determinar mediante Calorímetría diferencial de barrido (“Differential Scanning Calorimetry”, DSC) el calor específico y los parámetros termofísicos de la descomposición completa y la gelatinización, de la quinua (Chenopodium quinoa, kiwicha (Amaranthus caudatus) y la cañihua (Chenopodium pallidicaule). Para la determinación del calor específico se usaron cápsulas de aluminio y tomando de referencia el c.e del zafiro, observándose picos en el termograma, entre 50 y 60°C y calo...

  20. Looking at the label and beyond: the effects of calorie labels, health consciousness, and demographics on caloric intake in restaurants

    Science.gov (United States)

    2013-01-01

    Background Recent legislation has required calorie labels on restaurant menus as a means of improving Americans’ health. Despite the growing research in this area, no consensus has been reached on the effectiveness of menu labels. This suggests the possibility of heterogeneity in responses to caloric labels across people with different attitudes and demographics. The purpose of this study was to explore the potential relationships between caloric intake and diners’ socio-economic characteristics and attitudes in a restaurant field experiment that systematically varied the caloric information printed on the menus. Methods We conducted a field experiment in a full service restaurant where patrons were randomly assigned to one of three menu treatments which varied the amount of caloric information printed on the menus (none, numeric, or symbolic calorie label). At the conclusion of their meals, diners were asked to complete a brief survey regarding their socio-economic characteristics, attitudes, and meal selections. Using regression analysis, we estimated the number of entrée and extra calories ordered by diners as a function of demographic and attitudinal variables. Additionally, irrespective of the menu treatment to which a subject was assigned, our study identified which types of people are likely to be low-, medium-, and high-calorie diners. Results Results showed that calorie labels have the greatest impact on those who are least health conscious. Additionally, using a symbolic calorie label can further reduce the caloric intake of even the most health conscious patrons. Finally, calorie labels were more likely to influence the selection of the main entrée as opposed to supplemental items such as drinks and desserts. Conclusions If numeric calorie labels are implemented (as currently proposed), they are most likely to influence consumers who are less health conscious – probably one of the key targets of this legislation. Unfortunately, numeric labels did

  1. High Caloric Diet for ALS Patients: High Fat, High Carbohydrate or High Protein

    Directory of Open Access Journals (Sweden)

    Sarvin Sanaie

    2015-01-01

    . They showed that patients in the highcarbohydrate/high-calorie groups gained 0.39 kg more weight per month, compared with 0.11kg per month in the control group, and there was an average weight loss of 0.46 kg per month in the high-fat/high-calorie group. However, there are some concerns that highcarbohydrate low-fat diets might increase the risk of ALS and these findings should be interpreted with caution (4. Furthermore, according to Wills et al. high fat-high caloric diets could not be ideal regimens for these patients due to the associated gastrointestinal complications (3. Dorst and associates, in their study, showed that high caloric food supplement with high fat is suitable to establish body weight compared to high carbohydrate formula. Hence, it seems that high protein-high caloric diets could be more appropriate options for both improving negative nitrogen balance and decreasing muscle atrophy in patients with ALS based on the pathophysiology of proteinenergy malnutrition and hypermetabolism which is thought to be due to mitochondria problem. The multifactorial pathophysiology of ALS has resulted in hypotheses that there may be subgroups of patients, eventually defined by a specific underlying etiology or clinical presentation, which selectively respond to a particular regimen. Consequently, further RCTs with larger sample size are required to clarify the best regimen for weight gain and improved survival in ALS patients and it seems that personalized nutritional support or combined regimens might be the best way and could improve the quality of life considering the complex pathophysiology of malnutrition.

  2. Inoculación de trigo (Triticum aestivum, L. con rizobios adaptados a ecosistemas ganaderos de Alberta, Canadá Inoculation of wheat (Triticum aestivum, L. with rhizobia adapted to livestock ecosystems of Alberta, Canadá

    Directory of Open Access Journals (Sweden)

    C.J Bécquer

    2007-03-01

    Full Text Available Se efectuó un ensayo en invernadero con el objetivo de seleccionar cepas de rizobio inoculadas en trigo (Triticum aestivum, L., var. CDC Teal. Para ello se utilizaron 16 cepas nativas canadienses pertenecientes a Sinorhizobium medicae, así como 12 cepas comerciales. Los inóculos se confeccionaron en medio CLM y fueron agitados hasta alcanzar un título de 10(6-10(8 cél./mL. Se utilizaron los métodos estándar para la inoculación de cereales. Se construyó un dendrograma mediante el método de Ward (distancia euclidiana al cuadrado. Se evaluaron las variables: peso seco aéreo (PSA, peso seco raíz (PSR, longitud del tallo (LT, peso seco espigas (PSE y número de hijos (NH. Se constató un incremento significativo en todas las variables en los tratamientos inoculados con las cepas nativas y las cepas comerciales de rizobio, comparados con el testigo absoluto. En peso seco aéreo, peso seco espigas y peso seco raíz, la mayor parte de los tratamientos no difirieron significativamente del control fertilizado. En longitud del tallo existieron 17 tratamientos superiores estadísticamente con respecto al control fertilizado. Se seleccionaron 10 cepas del total. Los tratamientos seleccionados en el dendrograma constituyeron el 31% para las cepas nativas y el 42% para las comerciales. Se recomienda efectuar ensayos de campo con las cepas seleccionadas inoculadas en cereales de interés económico para Cuba.A greenhouse experiment was carried out in order to select rhizobium strains inoculated on wheat (Triticum aestivum, L., var. CDC Teal. For that 16 Canadian native strains, belonging to Sinorhizobium medicae, as well as 12 commercial strains, were used. The inocula were prepared in YMB medium and shaken up to obtain a title of 106-108 cells/mL. The standard methods for the inoculation of cereals were used. A dendrogram was constructed by means of the Ward's method (square Euclidian distance. The variables: aerial dry weight (ADW, dry weight of

  3. Hepatic mitochondrial energetics during catch-up fat after caloric restriction.

    Science.gov (United States)

    Crescenzo, Raffaella; Bianco, Francesca; Falcone, Italia; Prisco, Marina; Dulloo, Abdul G; Liverini, Giovanna; Iossa, Susanna

    2010-08-01

    The objective of the study was to investigate whether changes in liver mitochondrial energetics could underlie the enhanced energetic efficiency that drives accelerated body fat recovery (catch-up fat) during refeeding after caloric restriction. Rats were subjected to caloric restriction (50% of ad libitum intake) for 15 days and then refed for 1 or 2 weeks on an amount of chow equal to that of controls matched for weight at the onset of refeeding. Whole-body metabolism was characterized by energy balance and body composition determinations as well as by indirect calorimetric measurements of 24-hour energy expenditure, substrate oxidation, and whole-body de novo lipogenesis estimated from nonprotein respiratory quotient. Hepatic mitochondrial energetics were determined from measurements of liver mitochondrial mass, respiratory capacities, and proton leak (both basal and fatty acid stimulated), whereas hepatic oxidative status was assessed from measurements of hepatic mitochondrial lipid peroxidation, aconitase, and superoxide dismutase activity. Furthermore, hepatic lipogenic capacity was determined from assays of fatty acid synthase activity. Compared with controls, isocalorically refed rats showed an elevated energetic efficiency and body fat gain over both week 1 and week 2 of refeeding, as well as a lower 24-hour energy expenditure and higher rates of whole-body de novo lipogenesis at the end of both week 1 and week 2 of refeeding. Analysis of the liver revealed that after 1 week (but not after 2 weeks) of refeeding, the mitochondrial mass (but not mitochondrial density) was lower in refed rats than in controls, associated with higher state 3 mitochondrial respiratory capacity, increased superoxide dismutase activity, as well as higher fatty acid synthase activity. These results suggest that, although at the whole-body level elevations in energy efficiency and de novo lipogenesis are coordinated toward catch-up fat, the overall hepatic mitochondrial energetic

  4. Accumulation of long-chain glycosphingolipids during aging is prevented by caloric restriction.

    Directory of Open Access Journals (Sweden)

    María José Hernández-Corbacho

    Full Text Available BACKGROUND: Chronic kidney disease and end-stage renal disease are major causes of morbidity and mortality that are seen far more commonly in the aged population. Interestingly, kidney function declines during aging even in the absence of underlying renal disease. Declining renal function has been associated with age-related cellular damage and dysfunction with reports of increased levels of apoptosis, necrosis, and inflammation in the aged kidney. Bioactive sphingolipids have been shown to regulate these same cellular processes, and have also been suggested to play a role in aging and cellular senescence. METHODOLOGY/PRINCIPAL FINDINGS: We hypothesized that alterations in kidney sphingolipids play a role in the declining kidney function that occurs during aging. To begin to address this, the sphingolipid profile was measured in young (3 mo, middle aged (9 mo and old (17 mo C57BL/6 male mice. Interestingly, while modest changes in ceramides and sphingoid bases were evident in kidneys from older mice, the most dramatic elevations were seen in long-chain hexosylceramides (HexCer and lactosylceramides (LacCer, with C14- and C16-lactosylceramides elevated as much as 8 and 12-fold, respectively. Increases in long-chain LacCers during aging are not exclusive to the kidney, as they also occur in the liver and brain. Importantly, caloric restriction, previously shown to prevent the declining kidney function seen in aging, inhibits accumulation of long-chain HexCer/LacCers and prevents the age-associated elevation of enzymes involved in their synthesis. Additionally, long-chain LacCers are also significantly elevated in human fibroblasts isolated from elderly individuals. CONCLUSION/SIGNIFICANCE: This study demonstrates accumulation of the glycosphingolipids HexCer and LacCer in several different organs in rodents and humans during aging. In addition, data demonstrate that HexCer and LacCer metabolism is regulated by caloric restriction. Taken together

  5. EFEITO DAS ONDAS DE CALOR NA AGRICULTURA – SAFRA 2013/2014

    Directory of Open Access Journals (Sweden)

    Melhores Trabalhos .

    2015-02-01

    Full Text Available Ao aquecimento global, considerado decorrência do fenômeno popularmente conhecido como efeito estufa, têm sido atribuidas muitas das anomalias climáticas que ultimamente vêm afetando  municípios, regiões, países e até continentes inteiros. Uma dessas anomalias do clima refere-se às recentes ondas de calor ocorridas no verão de 2013/2014, agora findando, registradas nas estações meteorológicas e no desconforto de pessoas, plantas e animais que habitam a região sul da América do Sul, onde estão situados o Estado do Rio Grande do Sul e, nele,  o Município de Cruz Alta. Diante do exposto, este trabalho, na forma de artigo, tem por objetivo descrever e analisar a ocorrência de alguns desastres naturais, resultantes de fenômenos meteorológicos eventuais ou recorrentemente verificados e registrados no Estado e no Município, todos quase sempre capazes de afetar seu desenvolvimento socioeconômico. Os danos anuais causados por diferentes desastres meteorológicos sobre a agricultura são calculados, em termos globais ou mundiais, na ordem de mais 41 bilhões de dólares. Ao se efetuar uma análise sobre causas e efeitos dos fenômenos meteorológicos que incidem sobre a agricultura, tendo por base parte das informações bibliográficas, documentais e midiáticas consultadas para a elaboração deste artigo, tem-se que levar em consideração que esses fenômenos manifestam-se diferenciadamente quanto à quantização de danos e percentualidade de perdas que podem ocasionar aos cultivos agrícolas. Enquanto que os prejuízos causados por granizos, geadas e secas, por exemplo, podem ser avaliados por sintomas manifestos nas plantas (quebra e ruptura de partes de hastes e colmos, necrose foliar; congelamento de tecidos e de folhas, cobertura de gelo sobre plantas e solo; e murcha de folhas, redução de crescimento, etc. e pela visualização da intensidade de ocorrência (tamanho e número de pedras de granizo, cobertura de gelo e

  6. Study of electro-caloric effect in Ca and Sn co-doped BaTiO3 ceramics

    Science.gov (United States)

    Upadhyay, Sanjay Kumar; Fatima, Iram; Raghavendra Reddy, V.

    2017-04-01

    The present work deals with the study of structural, ferroelectric, dielectric and electro-caloric effects in lead free ferroelectric polycrystalline Ba1-x Ca x Ti0.95Sn0.05O3 (x  =  2, 5 and 10%) i.e. Ca, Sn co-doped BaTiO3 (BTO). Phase purity of the samples is confirmed from x-ray data by using Rietveld refinement. 119Sn Mössbauer reveals homogenous phase as well as iso-valent substitution of Sn at Ti site. Enhancements in ferroelectric and dielectric properties have been observed. Indirect method which is based on Maxwell equation has been used to determine the electro-caloric (EC) effect in the studied ferroelectric ceramics and maximum EC coefficient is observed for Ba0.95Ca0.05Ti0.95Sn0.05O3.

  7. Caloric Intake on the Sabbath: A Pilot Study of Contributing Factors to Obesity in the Orthodox Jewish Community.

    Science.gov (United States)

    Rosenberg, Deborah A; Swencionis, Charles; Segal-Isaacson, C J

    2016-10-01

    The American Orthodox Jewish community has specific cultural factors that may contribute to overweight and obesity. This study aimed to look at caloric intake on the Sabbath and its contribution to overweight and obesity. Twelve married or previously married women who identify themselves as Orthodox Jews were recruited to do 24-h food recalls over the phone. The participants were divided into three weight groups (normal, overweight, and obese) based on their BMI. The overweight and obese participants' data were combined into one group for the purposes of statistical testing. Paired t tests looking at the data for all participants showed significantly great caloric intake during an average Sabbath day than an average weekday [t(4) = 7.58, p Jewish community.

  8. Heat transformers simulation coupled to industrial processes and experimental evaluation of a thermal transformer of two KW power; Simulacion de transformadores de calor acoplados a procesos industriales y evaluacion experimental de un transformador termico de dos kw de potencia

    Energy Technology Data Exchange (ETDEWEB)

    Cerezo Roman, Jesus

    2001-12-15

    recovering temperature and between 42% and 96% at high temperature for the use of this additives. [Spanish] La quema de combustibles primarios en los diferentes sectores industriales y de transporte, han provocado grandes problemas de salud a la humanidad y contaminacion al medio ambiente, debido principalmente a sus altas emisiones de sustancias y gases, ademas de problemas socioeconomicos en muchos paises. Debido a esto, muchos paises estan investigando nuevas tecnologias alternas para su sustitucion. Uno de los principales tecnologias propuestas son los transformadores de calor. Estos equipos son capaces de ahorrar energia calorifica principalmente en procesos industriales. Debido a esto, estas tesis realiza estudios teoricos de transformadores de calor en procesos industriales tipicos de la region como es la destilacion de derivados de petroleo y refinacion de azucar morena, para observar la energia que puede ser ahorrada por el uso de estos equipos. Por otra parte se realizo una evaluacion experimental de un transformador de calor con aditivos debido a que aumentan la absorcion en el absorbedor, mejorando el coeficiente de operacion. En la simulacion de la columna de destilacion de petroleo se utilizo el simulador de procesos quimicos Aspen Plus version 9.3-2, debido a que este tiene modelos termodinamicos muy confiables para estudiar el comportamiento de cada uno de sus componentes. Los resultados mostraron que con el transformador de calor de una etapa operando con la mezcla LiBr-H{sub 2} O se puede ahorrar hasta un 45% de la energia suministra a la caldera y hasta un 32% con el transformador de doble absorcion. Para la modelacion de la refineria del azucar morena se uso el paquete Visual Basic, version 6.2. El paquete fue utilizado debido a que es un lenguaje grafico y de facil manejo. Los resultados mostraron que se puede recuperar hasta un 15% de la energia suministrada a la caldera. En la experimentacion se utilizo la mezcla bromuro de litio-agua y bromuro de

  9. Cytotoxic activity of butane type of 1,7-seco-2,7'-cyclolignanes and apoptosis induction by Caspase 9 and 3.

    Science.gov (United States)

    Wukirsari, Tuti; Nishiwaki, Hisashi; Nishi, Kosuke; Sugahara, Takuya; Akiyama, Koichi; Kishida, Taro; Yamauchi, Satoshi

    2014-09-01

    All stereoisomers of methoxybutane and fluorobutane type of 1,7-seco-2,7'-cyclolignane were synthesized and cytotoxic activities of these compounds were compared with those of all stereoisomers of butane and butanol type compounds. Both enantiomers of butane type secocyclolignane showed higher cytotoxic activity (IC50=16-20 μM) than methoxy type compounds, whereas none was observed for all the stereoisomers of butanol type secocyclolignane, however, (-)-Kadangustin J showed stereospecific cytotoxic activity (IC50=47-67 μM). Since (R)-9'-fluoro derivative 23 was most potent (IC50=19 μM) among the corresponding fluoro stereoisomers, (R)-9'-alkyl derivatives were synthesized, hydrophobic 9'-heptyl derivative 27 showing highest activity (IC50=3.7 μM against HL-60, IC50=3.1 μM against HeLa) in this experiment. Apoptosis induction caused by Caspase 3 and 9 for (R)-9'-heptyl derivative 27 was observed in the research on the mechanism. A degradation of DNA into small fragments was also shown by DNA ladder assay. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Giochiamo con i robot

    Directory of Open Access Journals (Sweden)

    Andrea Bonarini

    2009-01-01

    Full Text Available "Giochiamo con i robot" e' un laboratorio interattivo per grandi e piccini realizzato per l'edizione 2007 del Festival della Scienza di Genova. Lungo un percorso che va dalla telerobotica alla robotica evolutiva, il laboratorio sviluppa il tema di dare intelligenza ai robot. Questo percorso, le cui tappe sono le varie installazioni, si conclude nella "bottega" dove e' possibile costruire e programmare i propri robot o smontare e modificare quelli esposti durante il percorso didattico. I visitatori sono coinvolti in attivita' ludiche grazie alle quali possonoentrare in contatto con alcune delle idee potenti della robotica,

  11. Pensar con las manos

    OpenAIRE

    Campo Baeza, Alberto

    2009-01-01

    Cuántas veces habré repetido este hermoso poema de Blake a mis alumnos tratando de inculcarles cuánto de inefable tiene la mejor Arquitectura. "To see a World in a grain of sand" tiene bastante que ver con lo que es un pequeño dibujo en relación con el proyecto que es capaz de explicarnos. Si el diccionario dice que diagrama es la "figura gráfica que explica un fenómeno determinado", sabiendo que la arquitectura construida es tan compleja, nos sorprende la capacidad de un diagrama, un p...

  12. Caloric Vestibular Stimulation Reduces Pain and Somatoparaphrenia in a Severe Chronic Central Post-Stroke Pain Patient: A Case Study: e0151213

    National Research Council Canada - National Science Library

    Grazia Fernanda Spitoni; Giorgio Pireddu; Gaspare Galati; Valentina Sulpizio; Stefano Paolucci; Luigi Pizzamiglio

    2016-01-01

    .... To date, there is limited evidence for the effective treatments of this disease. Here we used caloric vestibular stimulation to reduce pain and somatoparaphrenia in a 57-year-old woman suffering from central post-stroke pain...

  13. Effect of replacing sugar with non-caloric sweeteners in beverages on the reward value after repeated exposure.

    Science.gov (United States)

    Griffioen-Roose, Sanne; Smeets, Paul A M; Weijzen, Pascalle L G; van Rijn, Inge; van den Bosch, Iris; de Graaf, Cees

    2013-01-01

    The reward value of food is partly dependent on learned associations. It is not yet known whether replacing sugar with non-caloric sweeteners in food is affecting long-term acceptance. To determine the effect of replacing sugar with non-caloric sweeteners in a nutrient-empty drink (soft drink) versus nutrient-rich drink (yoghurt drink) on reward value after repeated exposure. We used a randomized crossover design whereby forty subjects (15 men, 25 women) with a mean ± SD age of 21 ± 2 y and BMI of 21.5 ± 1.7 kg/m(2) consumed a fixed portion of a non-caloric sweetened (NS) and sugar sweetened (SS) versions of either a soft drink or a yoghurt drink (counterbalanced) for breakfast which were distinguishable by means of colored labels. Each version of a drink was offered 10 times in semi-random order. Before and after conditioning the reward value of the drinks was assessed using behavioral tasks on wanting, liking, and expected satiety. In a subgroup (n=18) fMRI was performed to assess brain reward responses to the drinks. Outcomes of both the behavioral tasks and fMRI showed that conditioning did not affect the reward value of the NS and SS versions of the drinks significantly. Overall, subjects preferred the yoghurt drinks to the soft drinks and the ss drinks to the NS drinks. In addition, they expected the yoghurt drinks to be more satiating, they reduced hunger more, and delayed the first eating episode more. Conditioning did not influence these effects. Our study showed that repeated consumption of a non-caloric sweetened beverage, instead of a sugar sweetened version, appears not to result in changes in the reward value. It cannot be ruled out that learned associations between sensory attributes and food satiating capacity which developed preceding the conditioning period, during lifetime, affected the reward value of the drinks.

  14. Effect of replacing sugar with non-caloric sweeteners in beverages on the reward value after repeated exposure.

    Directory of Open Access Journals (Sweden)

    Sanne Griffioen-Roose

    Full Text Available BACKGROUND: The reward value of food is partly dependent on learned associations. It is not yet known whether replacing sugar with non-caloric sweeteners in food is affecting long-term acceptance. OBJECTIVE: To determine the effect of replacing sugar with non-caloric sweeteners in a nutrient-empty drink (soft drink versus nutrient-rich drink (yoghurt drink on reward value after repeated exposure. DESIGN: We used a randomized crossover design whereby forty subjects (15 men, 25 women with a mean ± SD age of 21 ± 2 y and BMI of 21.5 ± 1.7 kg/m(2 consumed a fixed portion of a non-caloric sweetened (NS and sugar sweetened (SS versions of either a soft drink or a yoghurt drink (counterbalanced for breakfast which were distinguishable by means of colored labels. Each version of a drink was offered 10 times in semi-random order. Before and after conditioning the reward value of the drinks was assessed using behavioral tasks on wanting, liking, and expected satiety. In a subgroup (n=18 fMRI was performed to assess brain reward responses to the drinks. RESULTS: Outcomes of both the behavioral tasks and fMRI showed that conditioning did not affect the reward value of the NS and SS versions of the drinks significantly. Overall, subjects preferred the yoghurt drinks to the soft drinks and the ss drinks to the NS drinks. In addition, they expected the yoghurt drinks to be more satiating, they reduced hunger more, and delayed the first eating episode more. Conditioning did not influence these effects. CONCLUSION: Our study showed that repeated consumption of a non-caloric sweetened beverage, instead of a sugar sweetened version, appears not to result in changes in the reward value. It cannot be ruled out that learned associations between sensory attributes and food satiating capacity which developed preceding the conditioning period, during lifetime, affected the reward value of the drinks.

  15. Caloric restriction and intermittent fasting: Two potential diets for successful brain aging

    Science.gov (United States)

    Martin, Bronwen; Mattson, Mark P.; Maudsley, Stuart

    2008-01-01

    The vulnerability of the nervous system to advancing age is all too often manifest in neurodegenerative disorders such as Alzheimer's and Parkinson's diseases. In this review article we describe evidence suggesting that two dietary interventions, caloric restriction (CR) and intermittent fasting (IF), can prolong the health-span of the nervous system by impinging upon fundamental metabolic and cellular signaling pathways that regulate life-span. CR and IF affect energy and oxygen radical metabolism, and cellular stress response systems, in ways that protect neurons against genetic and environmental factors to which they would otherwise succumb during aging. There are multiple interactive pathways and molecular mechanisms by which CR and IF benefit neurons including those involving insulin-like signaling, FoxO transcription factors, sirtuins and peroxisome proliferator-activated receptors. These pathways stimulate the production of protein chaperones, neurotrophic factors and antioxidant enzymes, all of which help cells cope with stress and resist disease. A better understanding of the impact of CR and IF on the aging nervous system will likely lead to novel approaches for preventing and treating neurodegenerative disorders. PMID:16899414

  16. Transport of heat in caloric vestibular stimulation. Conduction, convection or radiation?

    Science.gov (United States)

    Feldmann, H; Hüttenbrink, K B; Delank, K W

    1991-01-01

    Experiments in temporal bone specimens were carried out under strictly controlled conditions: temperature (37 degrees C) and humidity kept constant; standardized irrigation of the external ear canal by an automated system (in 15 s, 50 ml of water, 11 degrees C above temperature of specimen), thermistor probes of 0.2 mm diameter placed in different parts of the specimens. In the intact temporal bone such an irrigation causes a rise in temperature with a gradient from the external ear canal across the bony bridge to the lateral semicircular canal as expected with heat conduction. After removal of the bony bridge, which is the main route for heat conduction, the rise in temperature in the lateral semicircular canal is greater and faster than in the intact specimen. This effect again is drastically reduced by placing a reflecting shield between tympanic membrane and labyrinth. In the intact middle ear inserting a reflecting shield or filling the cavity with gel also reduces the heat transfer to the labyrinth, although the bony routes for heat conduction are left untouched. The experiments prove that radiation plays an important part in heat transfer in caloric stimulation.

  17. Caloric restriction in grouped rats: aggregate influence on behavioural and hormonal data.

    Science.gov (United States)

    Moneo, Mikel; Martín Zúñiga, Jesús; Morón, Ignacio

    2017-10-01

    The majority of studies in short- and middle-term caloric restriction (CR) have been primarily focused on physiological parameters, improvements in aging, modulation of oxidative stress, and long-term negative effects on cognitive functions. However, single-housing associated with CR may pose many logistical problems. Thus, it is necessary to study the effects of CR under conditions in which animals are group-housed. The aims of this study were to (i) observe the possible differences in the proportion of the weights and social behaviour under ad libitum and CR (at 70%) conditions; (ii) examine the eventual inequalities in the proportion of the weights and social behaviour (the time spent eating under the feeder as an indicator of dominance and empathy, and the number of 'pushes' as an indicator of aggressiveness) in sibling and non-sibling rats under CR conditions; and (iii) compare the concentrations of corticosterone (stress biomarker) in serum under ad libitum and CR conditions. The results indicated the effectiveness of CR in different groups independent of the relationship between the rats. No extreme changes in weight were observed in the CR rats. Behavioural observations also indicated the differences in the total time spent under the feeder and in the number of pushes (higher in both cases for the sibling rats). However, no significant differences in corticosterone levels were observed. Our results suggest the viability of group-housing rats during long periods of CR maintenance.

  18. Caloric profile of pasteurized milk in the human milk bank at a university hospital.

    Science.gov (United States)

    de Moraes, Priscila Santa; de Oliveira, Márcia Maria B; Dalmas, José Carlos

    2013-01-01

    To verify the caloric and sanitary profile of human milk stored at the Human Milk Bank at Londrina University Hospital. Cross-sectional study. Data were obtained from the Human Milk Bank registry regarding the source, the amount collected in liters, the amount of calories by liter assessed by crematocrit, and the acidity of human milk determined by titration in degrees Dornic. Between 2006 and 2009, 30,846 samples of human milk were collected from donors coming from different locations and analyzed. A total of 5,869L of milk were collected and distributed. From the total human pasteurized milk, 53,5% was classified as hypocaloric (711kcal/L). Regarding the several locations where the milk was collected, the Human Milk Bank at Londrina University Hospital was the location in which a larger number of donations were observed in the three classifications. The result of the Dornic test for acidity of the collected milk revealed that 60.8% had 4.1º to 8.0º Dornic. A large volume of the collected human milk is hypocaloric and appropriate for human consumption. There is the need to intensify collection procedures in order to meet the demand for hypercaloric milk for preterm newborn infants.

  19. Differential responses of white adipose tissue and brown adipose tissue to caloric restriction in rats.

    Science.gov (United States)

    Okita, Naoyuki; Hayashida, Yusuke; Kojima, Yumiko; Fukushima, Mayumi; Yuguchi, Keiko; Mikami, Kentaro; Yamauchi, Akiko; Watanabe, Kyoko; Noguchi, Mituru; Nakamura, Megumi; Toda, Toshifusa; Higami, Yoshikazu

    2012-05-01

    Caloric restriction (CR) slows the aging process and extends longevity, but the exact underlying mechanisms remain debatable. It has recently been suggested that the beneficial action of CR may be mediated in part by adipose tissue remodeling. Mammals have two types of adipose tissue: white adipose tissue (WAT) and brown adipose tissue (BAT). In this study, proteome analysis using two-dimensional gel electrophoresis combined with MALDI-TOF MS, and subsequent analyses were performed on both WAT and BAT from 9-month-old male rats fed ad libitum or subjected to CR for 6 months. Our findings suggest that CR activates mitochondrial energy metabolism and fatty acid biosynthesis in WAT. It is likely that in CR animals WAT functions as an energy transducer from glucose to energy-dense lipid. In contrast, in BAT CR either had no effect on, or down-regulated, the mitochondrial electron transport chain, but enhanced fatty acid biosynthesis. This suggests that in CR animals BAT may change its function from an energy consuming system to an energy reservoir system. Based on our findings, we conclude that WAT and BAT cooperate to use energy effectively via a differential response of mitochondrial function to CR. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  20. Evaluation of dysphagia risk, nutritional status and caloric intake in elderly patients with Alzheimer's

    Directory of Open Access Journals (Sweden)

    Vanessa Fernanda Goes

    2014-04-01

    Full Text Available OBJECTIVE: to evaluate the risk of dysphagia and its relationship with the stage of Alzheimer's Disease, as well as the relationship between the risk of dysphagia and nutritional status and caloric intake in elderly people with Alzheimer's disease.METHODS: the sample consisted of 30 subjects of both genders with probable Alzheimer's disease. The stage of the disease, nutritional status, energy intake, and risk of dysphagia were assessed.RESULTS: it was found that increased risk of dysphagia is associated with the advance in the stages of Alzheimer's disease and that even patients in the early stages of disease have a slight risk of developing dysphagia. No association was found between nutritional status and the risk of dysphagia. High levels of inadequate intake of micronutrients were also verified in the patients.CONCLUSION: an association between dysphagia and the development of Alzheimer's disease was found. The results indicate the need to monitor the presence of dysphagia and the micronutrient intake in patients with Alzheimer's disease.

  1. Krebs cycle enzymes from livers of old mice are differentially regulated by caloric restriction.

    Science.gov (United States)

    Hagopian, Kevork; Ramsey, Jon J; Weindruch, Richard

    2004-08-01

    Krebs cycle enzyme activities and levels of five metabolites were determined from livers of old mice (30 months) maintained either on control or on long-term caloric restriction (CR) diets (28 months). In CR mice, the cycle was divided into two major blocks, the first containing citrate synthase, aconitase and NAD-dependent isocitrate dehydrogenase which showed decreased activities, while the second block, containing the remaining enzymes, displayed increased activity (except for fumarase, which was unchanged). CR also resulted in decreased levels of citrate, glutamate and alpha-ketoglutarate, increased levels of malate, and unchanged levels of aspartate. The alpha-ketoglutarate/glutamate and malate/alpha-ketoglutarate ratios were higher in CR, in parallel with previously reported increases with CR in pyruvate carboxylase activity and glucagon levels, respectively. The results indicate that long-term CR induces a differential regulation of Krebs cycle in old mice and this regulation may be the result of changes in gene expression levels, as well as a complex interplay between enzymes, hormones and other effectors. Truncation of Krebs cycle by CR may be an important adaptation to utilize available substrates for the gluconeogenesis necessary to sustain glycolytic tissues, such as brain.

  2. Caloric restriction reveals a metabolomic and lipidomic signature in liver of male mice.

    Science.gov (United States)

    Jové, Mariona; Naudí, Alba; Ramírez-Núñez, Omar; Portero-Otín, Manuel; Selman, Colin; Withers, Dominic J; Pamplona, Reinald

    2014-10-01

    Lipid composition, particularly membrane unsaturation, has been proposed as being a lifespan determinant, but it is currently unknown whether caloric restriction (CR), an accepted life-extending intervention, affects cellular lipid profiles. In this study, we employ a liquid chromatography quadrupole time-of-flight-based methodology to demonstrate that CR in the liver of male C57BL/6 mice: (i) induces marked changes in the cellular lipidome, (ii) specifically reduces levels of a phospholipid peroxidation product, 1-palmitoyl-2-glutaryl-sn-glycero-3-phosphatidylcholine, (iii) alters cellular phosphoethanolamine and triglyceride distributional profiles, (iv) affects mitochondrial electron transport chain complexes, increasing complex II and decreasing complex III and (v) is associated with specific changes in liver metabolic pathways. These data demonstrate that CR induces a specific lipidome and metabolome reprogramming event in mouse liver which is associated with lower protein oxidative damage, as assessed by mass spectrometry-based measurements. Such changes may be critical to the increased lifespan and healthspan observed in C57BL/6 mice following CR. © 2014 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.

  3. Artigos esterilizados em calor úmido: validação do sistema de guarda

    Directory of Open Access Journals (Sweden)

    Zilah Cândida Pereira das Neves

    2004-04-01

    Full Text Available Objetivamos identificar o tempo de validade da esterilização dos artigos processados pelo calor úmido, considerando as condições de esterilização e guarda. A validação deu-se através de testes microbiológicos realizados com instrumentais processados numa mesma carga e avaliados em tempos 0, 7, 10, 15 e 25 dias. Foram analisados 30% do instrumental de cada pacote que foi colocado em caldo Mueller Hinton e incubado a 37ºC por 72 horas. A leitura deu-se pela turvação do caldo. Das amostras avaliadas de nove cargas, em nenhuma houve crescimento microbiológico. Concluiu-se que apesar das condições de esterilização e guarda do material não se adequarem totalmente dentro dos parâmetros recomendados pela literatura, a esterilização ocorreu e manteve-se por um período de 25 dias.

  4. Caloric restriction improves efficiency and capacity of the mitochondrial electron transport chain in Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Joon-Seok; Choi, Kyung-Mi [College of Life Sciences and Biotechnology, Korea University, Seoul 136-701 (Korea, Republic of); Lee, Cheol-Koo, E-mail: cklee2005@korea.ac.kr [College of Life Sciences and Biotechnology, Korea University, Seoul 136-701 (Korea, Republic of)

    2011-06-03

    Highlights: {yields} Calorie restriction (CR) increases electron transport chain (ETC) at both RNA and protein level. {yields} CR enhances mitochondrial membrane potential, and, regardless of ages, reduces reactive oxygen species. {yields} CR increases both efficiency and capacity of the ETC. {yields} CR induces intensive modulation at mitochondrial ETC where might be a major site leading to extension of lifespan. -- Abstract: Caloric restriction (CR) is known to extend lifespan in a variety of species; however, the mechanism remains unclear. In this study, we found that CR potentiated the mitochondrial electron transport chain (ETC) at both the transcriptional and translational levels. Indeed, mitochondrial membrane potential (MMP) was increased by CR, and, regardless of ages, overall reactive oxygen species (ROS) generation was decreased by CR. With these changes, overall growth rate of cells was maintained under various CR conditions, just like cells under a non-restricted condition. All of these data support increased efficiency and capacity of the ETC by CR, and this change might lead to extension of lifespan.

  5. Maintenance of cellular ATP level by caloric restriction correlates chronological survival of budding yeast

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Joon-Seok; Lee, Cheol-Koo, E-mail: cklee2005@korea.ac.kr

    2013-09-13

    Highlights: •CR decreases total ROS and mitochondrial superoxide during the chronological aging. •CR does not affect the levels of oxidative damage on protein and DNA. •CR contributes extension of chronological lifespan by maintenance of ATP level -- Abstract: The free radical theory of aging emphasizes cumulative oxidative damage in the genome and intracellular proteins due to reactive oxygen species (ROS), which is a major cause for aging. Caloric restriction (CR) has been known as a representative treatment that prevents aging; however, its mechanism of action remains elusive. Here, we show that CR extends the chronological lifespan (CLS) of budding yeast by maintaining cellular energy levels. CR reduced the generation of total ROS and mitochondrial superoxide; however, CR did not reduce the oxidative damage in proteins and DNA. Subsequently, calorie-restricted yeast had higher mitochondrial membrane potential (MMP), and it sustained consistent ATP levels during the process of chronological aging. Our results suggest that CR extends the survival of the chronologically aged cells by improving the efficiency of energy metabolism for the maintenance of the ATP level rather than reducing the global oxidative damage of proteins and DNA.

  6. Caloric Restriction Protects against Lactacystin-Induced Degeneration of Dopamine Neurons Independent of the Ghrelin Receptor

    Directory of Open Access Journals (Sweden)

    Jessica Coppens

    2017-03-01

    Full Text Available Parkinson’s disease (PD is a neurodegenerative disorder, characterized by a loss of dopamine (DA neurons in the substantia nigra pars compacta (SNc. Caloric restriction (CR has been shown to exert ghrelin-dependent neuroprotective effects in the 1-methyl-4-phenyl-1,2,3,6-tetrathydropyridine (MPTP-based animal model for PD. We here investigated whether CR is neuroprotective in the lactacystin (LAC mouse model for PD, in which proteasome disruption leads to the destruction of the DA neurons of the SNc, and whether this effect is mediated via the ghrelin receptor. Adult male ghrelin receptor wildtype (WT and knockout (KO mice were maintained on an ad libitum (AL diet or on a 30% CR regimen. After 3 weeks, LAC was injected unilaterally into the SNc, and the degree of DA neuron degeneration was evaluated 1 week later. In AL mice, LAC injection significanty reduced the number of DA neurons and striatal DA concentrations. CR protected against DA neuron degeneration following LAC injection. However, no differences were observed between ghrelin receptor WT and KO mice. These results indicate that CR can protect the nigral DA neurons from toxicity related to proteasome disruption; however, the ghrelin receptor is not involved in this effect.

  7. Effects of Low-Dose Non-Caloric Sweetener Consumption on Gut Microbiota in Mice

    Directory of Open Access Journals (Sweden)

    Takashi Uebanso

    2017-06-01

    Full Text Available Abstract: Non-caloric artificial sweeteners (NASs provide sweet tastes to food without adding calories or glucose. NASs can be used as alternative sweeteners for controlling blood glucose levels and weight gain. Although the consumption of NASs has increased over the past decade in Japan and other countries, whether these sweeteners affect the composition of the gut microbiome is unclear. In the present study, we examined the effects of sucralose or acesulfame-K ingestion (at most the maximum acceptable daily intake (ADI levels, 15 mg/kg body weight on the gut microbiome in mice. Consumption of sucralose, but not acesulfame-K, for 8 weeks reduced the relative amount of Clostridium cluster XIVa in feces. Meanwhile, sucralose and acesulfame-K did not increase food intake, body weight gain or liver weight, or fat in the epididymis or cecum. Only sucralose intake increased the concentration of hepatic cholesterol and cholic acid. Moreover, the relative concentration of butyrate and the ratio of secondary/primary bile acids in luminal metabolites increased with sucralose consumption in a dose-dependent manner. These results suggest that daily intake of maximum ADI levels of sucralose, but not acesulfame-K, affected the relative amount of the Clostridium cluster XIVa in fecal microbiome and cholesterol bile acid metabolism in mice.

  8. Caloric restriction preserves memory and reduces anxiety of aging mice with early enhancement of neurovascular functions.

    Science.gov (United States)

    Parikh, Ishita; Guo, Janet; Chuang, Kai-Hsiang; Zhong, Yu; Rempe, Ralf G; Hoffman, Jared D; Armstrong, Rachel; Bauer, Björn; Hartz, Anika M S; Lin, Ai-Ling

    2016-11-08

    Neurovascular integrity plays an important role in protecting cognitive and mental health in aging. Lifestyle interventions that sustain neurovascular integrity may thus be critical on preserving brain functions in aging and reducing the risk for age-related neurodegenerative disorders. Here we show that caloric restriction (CR) had an early effect on neurovascular enhancements, and played a critical role in preserving vascular, cognitive and mental health in aging. In particular, we found that CR significantly enhanced cerebral blood flow (CBF) and blood-brain barrier function in young mice at 5-6 months of age. The neurovascular enhancements were associated with reduced mammalian target of rapamycin expression, elevated endothelial nitric oxide synthase signaling, and increased ketone bodies utilization. With age, CR decelerated the rate of decline in CBF. The preserved CBF in hippocampus and frontal cortex were highly correlated with preserved memory and learning, and reduced anxiety, of the aging mice treated with CR (18-20 months of age). Our results suggest that dietary intervention started in the early stage (e.g., young adults) may benefit cognitive and mental reserve in aging. Understanding nutritional effects on neurovascular functions may have profound implications in human brain aging and age-related neurodegenerative disorders.

  9. Effects of Caloric Restriction on Age-Related Hearing Loss in Rodents and Rhesus Monkeys

    Science.gov (United States)

    Someya, Shinichi; Tanokura, Masaru; Weindruch, Richard; Prolla, Tomas A.; Yamasoba, Tatsuya

    2014-01-01

    Age-related hearing loss (AHL), also known as presbycusis, is a universal feature of mammalian aging and is the most frequently occurring sensory disorder in the elderly population. AHL is characterized by a decline of auditory function and loss of hair cells and spiral ganglion neurons in the cochlea of the inner ear. It has been postulated that AHL occurs gradually as a result of the cumulative effect with aging of exposure to noise, diet, oxidative damage, and mitochondrial DNA mutations. However, the molecular mechanisms of AHL remain unclear and no preventative or therapeutic interventions have been developed. A growing body of evidence suggests increased oxidative damage with aging to macromolecules such as DNA, proteins, and lipids may play a causal role in aging and age-related diseases. Caloric restriction (CR) extends the lifespan of most mammalian species, delays the onset of multiple age-related diseases, and attenuates both the degree of oxidative damage and the associated decline in physiological function. Here, we review studies on CR’s ability to prevent cochlear pathology and AHL in laboratory animals and discuss potential molecular mechanisms of CR’s actions. PMID:20298166

  10. Entropy Generation and Human Aging: Lifespan Entropy and Effect of Diet Composition and Caloric Restriction Diets

    Directory of Open Access Journals (Sweden)

    Carlos A. Silva

    2009-01-01

    Full Text Available The first and second laws of thermodynamic were applied to statistical databases on nutrition and human growth in order to estimate the entropy generation over the human lifespan. The calculations were performed for the cases of variation in the diet composition and calorie restriction diets; and results were compared to a base case in which lifespan entropy generation was found to be 11 404 kJ/K per kg of body mass, predicting a lifespan of 73.78 and 81.61 years for the average male and female individuals respectively. From the analysis of the results, it was found that changes of diet % of fat and carbohydrates do not have a significant impact on predicted lifespan, while the diet % of proteins has an important effect. Reduction of diet protein % to the minimum recommended in nutrition literature yields an average increase of 3.3 years on the predicted lifespan. Changes in the calorie content of the diet also have an important effect, yielding a % increase in lifespan equal or higher than the % reduction in the diet caloric content. This correlates well experimental data on small mammal and insects, in which lifespan has been increased by diet restriction.

  11. Cardiovascular risk escalation with caloric excess: a prospective demonstration of the mechanics in healthy adults.

    Science.gov (United States)

    Gupta, Alok K; Johnson, William D; Johannsen, Darcy; Ravussin, Eric

    2013-01-24

    The link between weight gain and cardiovascular risk characterized with circadian blood pressure variability [CBPV] and endothelial function [EF] is unexplored. To prospectively demonstrate weight gain in healthy adults, increases body fat [BF], enlarges waist circumference [WC], expands visceral adipose tissue [VAT], exacerbates systemic inflammation [sIF], worsens insulin resistance [IR] and enhances functional cardiovascular disease [CVD] risk. Healthy men [n=11] and women [n=3] provided initial and eight-week post-caloric excess anthropometric and fasting laboratory measures. Functional CVD risk assessments: CBPV and resting EF were also obtained with 7-day automatic ambulatory BP monitoring and increased test finger peripheral arterial tone [PAT] relative to control [reported as relative hyperemia index (RHI)], respectively. After determining individualized mean energy requirements for weight maintenance over 7-days, each participant received a personalized over feeding prescription (1.4 times; 41% carbohydrate, 44% fat, and 15% protein) for 8-weeks. mean (SEM). Participants increased body weight [BW; +7.4(0.1) kg]*, body mass index [BMI; +2.5(0.2) kg/m²]*, BF [+2.0(0.01)%]*, WC [+8.2(1.0) cm]*, and VAT [+0.2(0.03) L]* and intrahepatic lipid [IHL + 0.0004(0.002) L] :*all p risk [measured as abnormal circadian blood pressure variability and impaired resting endothelial function].

  12. Attentional biases to foods: The effects of caloric content and cognitive restraint.

    Science.gov (United States)

    Forestell, Catherine A; Lau, Pia; Gyurovski, Ivo I; Dickter, Cheryl L; Haque, Sabrina S

    2012-12-01

    The goal of the present study was to determine whether female restrained and unrestrained eaters demonstrated differential levels of attentional bias to high calorie foods when they were presented as distractors in a flanker task. This task consisted of four blocks of 68 trials in which three food pictures were briefly presented simultaneously on a computer screen. On each trial a high or low calorie target food was presented in the center of a pair of high or low calorie food flanker pictures and participants' reaction times to answer a basic question about whether they would consume the target food for breakfast were recorded. In Experiment 1, in which all participants were fed a snack prior to engaging in the flanker task, there was no evidence that restrained (n=29) or unrestrained (n=37) eaters had an attentional bias. However, in Experiment 2, when participants completed the flanker task while hungry, restrained eaters (n=27) experienced response conflict only when low calorie targets were flanked by high calorie distractors, whereas unrestrained eaters (n=46) were distracted by high calorie flankers regardless of the caloric content of the target cue. The results from this implicit task indicate that flankers interfere with hungry participants' responses to varying degrees depending on their cognitive restraint. Whether attentional bias to food cues subsequently affects food choices and eating behavior is a topic for further investigation. Published by Elsevier Ltd.

  13. Historical evolution of slope instability in the Calore River Basin, Southern Italy

    Science.gov (United States)

    Diodato, Nazzareno; Soriano, Marcella; Bellocchi, Gianni; Fiorillo, Francesco; Cevasco, Andrea; Revellino, Paola; Guadagno, Francesco Maria

    2017-04-01

    There is interest in knowing historical spatio-temporal patterns of landslide activity. However, this is challenging to reconstruct because it is difficult to obtain detailed records for past landslide activity. Here, we deal with hydro-geomorphological signatures, such as storms, downpours, floods, snowmelt and mass movement, to detect annual slope instability events (ASIEs) over historical times. In order to obtain ASIEs for each year, a monthly Instability Density Index (IDI) was used and then monthly values were summed up to obtain a yearly value. Classes of monthly IDI varying between 0 (no instability) and 4 (highest instability) were determined from historical documents. We present an application for the Calore River Basin, Southern Italy, using data from a 313-year long series (1701-2013 CE). After 1880 CE the information becomes more valuable with directly observed landslide frequency. By this cataloguing, 129 ASIEs were obtained. Their evolution shows slight instability during the 18th century. Uneven and greater slope instability occurred instead across the 19th century, when an important phase of deforestation coincided with intensification of agricultural activities. Slope instability events continued during the 20th century but their causes are mainly related to anthropisation and the effects of recent climate change. It was determined that stormy autumns until the 19th century and successive winter-times with enhanced snowmelt, may have driven the reactivation of widespread instability events. We also found that mountainous and hilly terrains have an acute sensitivity to climate change.

  14. Adipose-immune interactions during obesity and caloric restriction: reciprocal mechanisms regulating immunity and health span.

    Science.gov (United States)

    Dixit, Vishwa Deep

    2008-10-01

    Increasing evidence suggests a tight coupling of metabolic and immune systems. This cross-talk mediated by neuroendocrine peptides as well as numerous cytokines and chemokines is believed to be responsible for integrating energy balance to immune function. These neuroendocrine-immune interactions are heightened during the state of chronic positive energy balance, as seen during obesity, and negative energy balance caused by caloric restriction (CR). Emerging evidence suggests that obesity may be associated with an immunodeficient state and chronic inflammation, which contribute to an increased risk of premature death. The direct interactions between expanded leukocyte populations within the adipose tissue during obesity and an increased number of adipocytes within an aging lymphoid microenvironment may constitute an important adaptive or pathological response as a result of change in energy balance. In stark contrast to obesity, CR causes negative energy balance and robustly prolongs a healthy lifespan in all of the species studied to date. Therefore, the endogenous neuroendocrine-metabolic sensors elevated or suppressed as a result of changes in energy balance may offer an important mechanism in understanding the antiaging and potential immune-enhancing nature of CR. Ghrelin, one such sensor of negative energy balance, is reduced during obesity and increased by CR. Ghrelin also regulates immune function by reducing proinflammatory cytokines and promotes thymopoiesis during aging and thus, may be a new CR mimetic target. The identification of immune effects and molecular pathways used by such orexigenic metabolic factors could offer potentially novel approaches to enhance immunity and increase healthy lifespan.

  15. Molecular simulation of caloric properties of fluids modelled by force fields with intramolecular contributions: Application to heat capacities.

    Science.gov (United States)

    Smith, William R; Jirsák, Jan; Nezbeda, Ivo; Qi, Weikai

    2017-07-21

    The calculation of caloric properties such as heat capacity, Joule-Thomson coefficients, and the speed of sound by classical force-field-based molecular simulation methodology has received scant attention in the literature, particularly for systems composed of complex molecules whose force fields (FFs) are characterized by a combination of intramolecular and intermolecular terms. The calculation of a thermodynamic property for a system whose molecules are described by such a FF involves the calculation of the residual property prior to its addition to the corresponding ideal-gas property, the latter of which is separately calculated, either using thermochemical compilations or nowadays accurate quantum mechanical calculations. Although the simulation of a volumetric residual property proceeds by simply replacing the intermolecular FF in the rigid molecule case by the total (intramolecular plus intermolecular) FF, this is not the case for a caloric property. We describe the correct methodology required to perform such calculations and illustrate it in this paper for the case of the internal energy and the enthalpy and their corresponding molar heat capacities. We provide numerical results for c P , one of the most important caloric properties. We also consider approximations to the correct calculation procedure previously used in the literature and illustrate their consequences for the examples of the relatively simple molecule 2-propanol, CH 3 CH(OH)CH 3 , and for the more complex molecule monoethanolamine, HO(CH 2 ) 2 NH 2 , an important fluid used in carbon capture.

  16. Molecular simulation of caloric properties of fluids modelled by force fields with intramolecular contributions: Application to heat capacities

    Science.gov (United States)

    Smith, William R.; Jirsák, Jan; Nezbeda, Ivo; Qi, Weikai

    2017-07-01

    The calculation of caloric properties such as heat capacity, Joule-Thomson coefficients, and the speed of sound by classical force-field-based molecular simulation methodology has received scant attention in the literature, particularly for systems composed of complex molecules whose force fields (FFs) are characterized by a combination of intramolecular and intermolecular terms. The calculation of a thermodynamic property for a system whose molecules are described by such a FF involves the calculation of the residual property prior to its addition to the corresponding ideal-gas property, the latter of which is separately calculated, either using thermochemical compilations or nowadays accurate quantum mechanical calculations. Although the simulation of a volumetric residual property proceeds by simply replacing the intermolecular FF in the rigid molecule case by the total (intramolecular plus intermolecular) FF, this is not the case for a caloric property. We describe the correct methodology required to perform such calculations and illustrate it in this paper for the case of the internal energy and the enthalpy and their corresponding molar heat capacities. We provide numerical results for cP, one of the most important caloric properties. We also consider approximations to the correct calculation procedure previously used in the literature and illustrate their consequences for the examples of the relatively simple molecule 2-propanol, CH3CH(OH)CH3, and for the more complex molecule monoethanolamine, HO(CH2)2NH2, an important fluid used in carbon capture.

  17. Trombose induzida pelo calor endovenoso: relato de dois casos tratados com rivaroxabana e revisão da literatura

    Directory of Open Access Journals (Sweden)

    Walter Junior Boim de Araujo

    2016-01-01

    Full Text Available Resumo Define-se trombose induzida pelo calor endovenoso como a propagação do trombo a partir de uma veia superficial em direção a uma veia mais profunda. Em geral, é considerada clinicamente insignificante quando não há propagação do trombo para o sistema venoso profundo. Essa condição pode ser tratada com terapia anticoagulante, embora a observação pareça ser suficiente, principalmente para graus menores. Neste estudo, relatamos dois casos de trombose induzida pelo calor endovenoso que teriam indicação de heparina de baixo peso molecular até a resolução do quadro. Porém, optou-se pelo uso da rivaroxabana (15 mg de 12 em 12h, com resolução completa do trombo em 4 semanas (caso 1 e em 7 dias (caso 2. A rivaroxabana pode ser uma alternativa promissora no tratamento da trombose induzida pelo calor endovenoso avançada, pela simplicidade da posologia, sem comprometimento da eficácia ou da segurança. São necessários estudos prospectivos, randomizados e controlados que possibilitem melhor entendimento da condição e o desenvolvimento de recomendações mais definitivas sobre opções de prevenção e tratamento.

  18. Extension of Drosophila Lifespan by Rhodiola rosea Depends on Dietary Carbohydrate and Caloric Content in a Simplified Diet.

    Science.gov (United States)

    Schriner, Samuel E; Coskun, Volkan; Hogan, Sean P; Nguyen, Cindy T; Lopez, Terry E; Jafari, Mahtab

    2016-03-01

    The root and rhizome extract of Rhodiola rosea has been extensively used in traditional medicine to improve physical and mental performance and to protect against stress. We, and others, have reported that R. rosea can extend lifespan in flies, worms, and yeast. We also previously found that the extract can act independently of dietary restriction (DR), a treatment that can extend lifespan in a range of model organisms. In flies, DR is implemented through a reduction in dietary yeast content. Here, we report that the ability of R. rosea extract to extend lifespan in flies is dependent on the carbohydrate and caloric content when supplemented with a simplified diet composed of yeast and sucrose. R. rosea extract elevated the sugar content in flies and down-regulated hexokinase expression, suggesting that it perturbs carbohydrate metabolism in flies. In our previous studies, bananas, barley malt, and corn syrup provided dietary carbohydrates, and R. rosea extract could extend lifespan with a range of caloric levels. We conclude that the lifespan-extending effect of R. rosea extract in flies is dependent on dietary carbohydrate and caloric contents coupled with an interaction with complex dietary components present in bananas, barley, or corn.

  19. [Index of Nutritional Purchasing Power Parity: comparison of caloric costs of a healthy versus an unhealthy diet].

    Science.gov (United States)

    Mendoza Velázquez, Alfonso

    2012-01-01

    Develop the Index of Nutritional Purchasing Power Parity (Nut3-CiO) as an instrument to compare the caloric costs of a healthy versus an unhealthy diet between regions or cities in a country over time. Indices of caloric prices were constructed and the "law of one price" was used to derive the Nut3-CiO index. Caloric inflation rates were obtained using basic descriptive statistics. The Nut3-CiO was applied in the major cities of Mexico during the period from January 1996 to December 2010. The statistical behavior of the Nut3-CiO revealed that, in Mexican cities, products for a typical diet are less expensive than products for a healthy diet. The findings showed a cyclical behavior to the index, a high correlation between inflation for the typical diet and inflation for the market basket, and a high persistence of prices. The Nut3-CiO index makes it possible to periodically compare the price differential of two types of diets-typical and healthy-between cities in a single country. This instrument could help health authorities identify the cities where it is easier or more difficult for consumers to access a typical or healthy diet in terms of cost. Furthermore, it makes it possible to estimate the percentage adjustment necessary in each city to attain levels of nutritional purchasing power parity.

  20. Neuroimaging to detect cortical projection of vestibular response to caloric stimulation in young and older adults using functional near-infrared spectroscopy (fNIRS).

    Science.gov (United States)

    Karim, H T; Fuhrman, S I; Furman, J M; Huppert, T J

    2013-08-01

    Functional near-infrared spectroscopy (fNIRS) is a non-invasive and portable neuroimaging technique. The method uses non-ionizing laser light in the range of red to near-infrared to detect changes in cerebral blood oxygenation. In this study, we used fNIRS to investigate cortical hemodynamic changes in the temporo-parietal and frontal regions during caloric vestibular stimulation. Caloric stimulation has previously been investigated using functional magnetic resonance imaging (fMRI) and positron emission tomography (PET), which serves as a validation of the fNIRS imaging modality toward the measurement of vestibular related brain regions. To date, only a single study has used fNIRS during caloric irrigations, which observed blood volume changes in the temporal-parietal area in healthy younger subjects. In this current study, fNIRS was used to measure cortical vestibular activation in 10 right-handed younger subjects (5 male and 5 female, age 25+/-6 years) and 10 right-handed older subjects (6 male and 4 female, age 74+/-5 years). We investigated both warm (44 °C) and cool (30 °C) unilateral caloric vestibular stimulation. Consistent with previous reports, we found that warm (44 °C) caloric irrigation caused a bilateral activation. In addition, we found that cool (30 °C) caloric irrigation caused contralateral activation of the temporo-parietal area. This study is the first to investigate age effects of the caloric stimulation on brain activity. We found that the older subjects had stronger bilateral effects than the younger subjects. Our results confirm previous fMRI and PET studies that showed cortical activation during caloric vestibular irrigation is dependent on side of irrigation, and temperature of irrigation. Furthermore, our results demonstrate that fNIRS is a viable technique in measuring cortical effects during vestibular tasks. Copyright © 2013 Elsevier Inc. All rights reserved.